Environment Science Class âIX

Approved by Government of Nepal, MoE, Curriculum Development Center, Sanothimi, Bhaktapur

Environment Science Class –IX

Authors: Prakash Parajuli Bishnu Parajuli MSc MSc

ASIA PUBLICATIONS PVT. LTD. Bagbazar, Kathmandu, Nepal Tel: 4232879, 4239174 Fax.: 4239190

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Title

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Environment Science–IX

Publisher

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ASIA PUBLICATIONS PVT. LTD.

Bagbazar, Kathmandu Author Edition © Computer Setting & Design

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Tel: 4232879, 4239174 Fax. 4239190 Writer First– 2014 A.D. Publisher Asia Desktop

Price : Rs………..0/–

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Preface Present 21st century is an age of science and technology. Every day is a day of new discovery, invention and achievement in the field of science and technology. The achievement of science is great; it changes the life style of a people from ancient Stone Age to this facilitated modern age. But science can’t create new natural aspects over air, water, soil etc. rather it changes condition of them. According to this, in today’s world there has been growing concern about environment and its conservation at all levels local, national and international. It is clear that human activities are the prime factors for this. The balance between the population and natural resources creates the happy, healthy and prosperous life which is the basis of quality of life. In present days the population is increasing in a tremendous rate and produces direct effect on environment. This book Environment Science, Grade IX as an optimal subject has been written according to the curriculum prescribed by curriculum development centre (CDC). It is mainly designed for grade IX students of the English medium and private schools, to fulfill the needs of students and teachers. There is a lack of suitable informative, reliable, complete and useful book of environment science in the market. This creates confusing and problems among the student and teacher within the depth and sequential arrangement of course content. We hope this book will be helpful to overcame all these lacks. Today, students are highly Intelligent and curious about any subjective matter regarding answers to the problems. To fulfill these demands different environmental facts and sufficient knowledge about the course content are presented in a sequential order. Sufficient problems are given as exercise according to the questions pattern designed by the CDC i.e. Very short questions, Short questions, Long questions and practical problems are mentioned in each topic. In this book most of the information is collected from internet, references book, magazines and published article from different individuals and organization. Hope this book will be fruitful and complete for the secondary level students for their upcoming SLC examination and also a basis for the higher study in environment education. This book is a result of long inspiration and moral support of many visible and invisible persons. We are thankful to Mr. Pradip Parajuli for co-operative help during writing book and collecting materials. At last, heartily thanks to Mr. Nabanidhi Pant, Mr. Alok Lamsal of Asia publication for publishing this book and both of Himal G.C, Kumar Dulal for their attractive layout designing of this book. We have tried our best to avoid errors in the presentation of contents, and we are entirely responsible for the errors, if any, found in the book. We will be thankful to all the readers who point out the weakness and provided us with suggestions for the improvement of the book.

Authors

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CONTENTS Page No. Unit –1

1.1 1.2 1.3 1.4

Components of Environment Concept of Environment Environment Education Elements of Environment Need and Importance of Environment Education

1 1 2 5

Unit –2 2.1 2.2

2.3

Ecology and Ecosystem Introduction 2.1.1 Components of the ecosystem Terrestrial Ecosystem 2.2.1 Forest Ecosystem 2.2.2 Tropic Level 2.2.2 Energy Flow in an Ecosystem Mountain Ecosystem

9 9 11 11 12 12 13

Unit –3

3.1 3.2

3.3 3.4

3.5

3.6

Environmental pollution Pollution Water pollution 3.2.1 Sources of water pollution 3.2.2 Water pollutants 3.2.4 Controlling measures of water pollution 3.2.5 Water Purification Quality of Air Air pollution 3.4.1 Sources of air pollution 3.4.2 Effects of Air Pollution 3.4.3 Major Air pollutants 3.4.4 Acid Rain Noise pollution 3.5.1 Causes of Noise Pollution 3.5.2 Effects of noise pollution Industrial Pollution 3.6.1 How do Industries Affect the Environment? 3.6.2 Effects of the industrial pollution 3.6.3 Controlling measures can be summarized in the following headings

15 15 15 17 18 19 20 21 21 22 23 24 26 27 28 29 30 31

Unit –4

4.1

Change in Climate Introduction 4.1.1 Causes of the climate change

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37 37

4.2

4.3 4.4

Global warming 4.2.2 Causes of the global warming 4.2.3 Effects of the global warming Effects of Global Warming in Nepal Controlling measures of the global warming and climate change

39 39 41 42 43

Unit –5 Natural Resources: Water and Soil 5.1

5.2

Water 5.1.2 5.1.3 5.1.4 Soil 5.2.3 5.2.4 5.2.5 5.2.6

Importance of Water Sources of water Measures for the conservation of the water resources Soil Profile Types of the soil of Nepal Soil Erosion Soil conservation

47 47 48 50 51 51 53 54 55

Unit –6

6.1 6.2 6.3 6.4 6.5 6.5 6.5

Natural Resources: Indigenous Plants and Animals Introduction Importance Some important indigenous Plants and animals found in Nepal Endangered / Rare animals of Nepal Causes of extinction of animals Ways of conserving animals and Plants Wild Animal Conservation in Nepal

59 59 60 62 71 73 75

Unit –7

7.1 7.2 7.3 7.4 7.5 7.6 7.7

Energy Energy Sources of energy Conservation of the energy Conservation measure of the renewable natural resources Conservation Measures of Non-Renewable Natural Resources Effects of Non-Conserving Energy in the Environment Energy crisis

79 81 87 89 90 90 91

Unit –8

8.1

8.3 8.4 8.5

Environment and Sustainable development Introduction 8.2.1 Sustainable development 8.2.2 Importance and Need of sustainable Development Role of education in sustainable development Eco- Technology in Development Eco-friendly Lifestyle

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93 93 94 95 95 97

Syllabus 1.

2.

3.

4.

5.

6.

7.

Elements of environment 1.1 Concept of environment 1.2 Elements of environment 1.3 Importance and need of environmental education. Ecology and ecosystem 2.1 Ecology and ecosystem : introduction 2.2 Forest ecosystem 2.3 Trophic level 2.4 Mountainous ecosystem 2.5 Trophic level Environmental pollution 3.1 Environmental pollution : introduction 3.2 Water pollution (Introduction, cause and effect, controlling measures, cause of pollution of surface water (organic, inorganic, chemical) 3.3 Quality air 3.4 Air pollution (introduction, causes and effects, smoke from vehicles, industrial effects, acid rain) 3.5 Noise pollution (introduction, causes and effects, controlling measures) 3.6 Industrial pollution (introduction, causes and effects, controlling measures) Climate change and its effects 4.1 Climate change and its effects (introduction, causes) 4.2 Global warming (causes and effects) 4.3 Effects of the global warming in Nepal (Glacier lake outburst flood, melting of Snow, flood and Landslide, impacts on Plant and Animals) Natural Resources 5.1 Water (Sources, importance, conservation) 5.2 Soil (Importance, types, profile) 5.3 Soil degration and Conservation 5.4 Indigenous Plant and animals (importance, cause of extinction, effects of extinction and conservation ways) Energy 6.1 Energy (Introduction and importance, sources) 6.2 Renewable ( Solar energy, Hydroelectricity, Wind Energy, Biomass, Geothermal) 6.3 Non-Renewable Energy 6.4 Energy conservation Environment and sustainable development 7.1 Introduction and importance 7.2 Role of environment education in sustainable development 7.3 Eco-technology in development

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7.4

Eco-friendly lifestyle

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Specification Grid, 2069 Environmental Science (Optional I) The examination of the environment science is divided into two parts: Theory and Practical. The full marks for the theoretical examination is 75 and that of Practical is 25. The question pattern for theoretical exam is as follows: Types of the Level Numbers Marks of each Total marks question question Very short Knowledge 11 1 11 questions Short questions Understanding 8 5 40 Long questions Higher ability 2 12 24 Total 21 75 The very short and short questions must cover all the units of the course and the long questions may cover one or more than one unit also. For the practical examination one –one project work must be done from each subject area stated below: S.N. Subject area Number Full of the marks work to be done 1  Study of the any one grassland ecosystem 1 5  Study of the any one forest ecosystem 2  Case study of water pollution 1 5  Case study of soil pollution  Case study of industrial pollution 3  Study of the conservation of the source of the water 1 5 in local area  Study of the conservation of the soil in local area 4  Study of the non-renewable energy within the local 1 5 area 5  Study of the any one case study of eco-friendly 1 5 lifestyle in the local area. Evaluation basis: 7.1 Report writing 7.2 Presentation 7.3 Viva

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UNIT Components of Environment 1.1. Concept of Environment The term 'environment' means surroundings which include physical, chemical, biological, cultural and social conditions of nature. Environment can be defined as all external conditions or influences under which an organism lives or develops. Survival, reproduction, growth and development of an organism are determined by the environment. The living organisms, e.g. plants, animals including human beings' and non-living organisms are found on the earth. None of the living organism can survive alone. The living organisms depend on each other and the environment as a whole to survive Environment is a valuable gift of nature as well as a creation of man. It consists of all things that surround us. It is made up of all living organisms and non-living objects. Man, animals, birds, insects, Worms, land water, mountains, seas, rivers, air, minerals, etc. are components of the environment. These things are found in nature. Even the man-made things like settlement, building, factory dam, road, vehicle and others are found in the environment. Social institutions and organizations are also part of the environment. Therefore, the environment is composed of biological, physical, social and cultural factors. Similarly, all stars, planets, satellites, etc. that form solar system are also environmental components. These components of the environment depend on each other, react and interact among themselves in a natural process. Humans are the important part of the environment. They use various components of the environment of their survival and benefits. Hence, it is their duty and responsibility to conserve and promote the environmental resources while using them. The ruthless exploitation of the environmental resources will create an imbalance in the environment.

1.2. Environment Education Environment education teaches us to keep the surrounding clean. Everyone needs neat and clean environment for healthy life. Environment education teaches about the surrounding around us and creates awareness to keep the environment clean. Environment education helps in understanding the surrounding and helps to improve and to keep it in good condition. All the external factors which affect human life and its development is environment. The natural state or situation and the arrangement made by human beings for development create the form of the environment. The environment covers various aspects of human beings, plants, trees and other creatures. Environment education makes us aware of the consequences resulting from the interaction of man with natural and manmade environment. It also makes us aware of the consequences resulting from its interaction with biological, physical, social, economic and cultural traditions. Besides, it provides skill, morality and knowledge to bear the responsibility to solve the environmental problems, to manage and maintain its qualities through various activities. Thus, environment education develops useful knowledge, skill and concept of all natural surroundings, human beings, biological things along with cultural, social, economic and moral aspects. Some well known Definitions on Environment and Environmental Education "Environment is the sum of total of all the external conditions and its influences on the development cycle of biotic elements."

Components of Environment 1

“Environmental Education is a process aimed at developing the world population that is aware of and concerned about the total environment and its associated problems, and which has the knowledge, attitude, motivation, commitments and skill to work individually and collectively towards the solution of current problems as well as the prevention of new one.”

1.3.

Elements of Environment

Different living and non-living things make the environment. All the things found in the earth like land plants and trees, animals etc. are the environment elements. Environment is composed of many elements. Each environment has its own distinct elements or components though all are interrelated and inter dependent and are parts of a complex whole. The environment can be classified in the following ways. Environment

Natural factors

Biological factors

Anthropogenic factors

Physical factors

1.3.1 Natural Environment

Socio-economic factors

Cultural and Religious factors

It consists of all living and non living things such as plants, birds, soil, Air River, mountains etc. which are made by nature. Things which are made by nature are called natural things. The environment which is made by natural things is known as natural environment. The natural environment is classified into two parts. a) b) a)

Biological Environment and Physical environment

Biological Environment

The environment which is formed by the combination of all living things is called the biological environment. The natural vegetation, birds, insects and animals including man come under the biological environment. Biological environment consists of all' living beings of the world. All the biological components are interdependent. None of the living organisms can survive alone in the earth's surface. Man and animals depend upon plants for food. Animals and birds feed meat, milk and eggs to man. Birds and animals survive consuming the grains and fruits of plants and trees' so, all plants depend on man for protection and man depends on plants and animals for food and comforts. The biological environment can be divided into two parts. 1. 2. 1.

Animal group and Vegetation group

Animal Group: The birds, animals and other insects come under the animal group. The animals like cow, goat, horse, buffalo, cat, tiger, lion, bear, elephant, etc. come under this group. The birds like parrot, dove, crow mynah, peacock, hen, etc. also come under this group. Besides these, crocodile, lizard, butterfly, fish, snake and other tiny insects also come under this group. So, the animals of this group can be divided into three categories like water creatures, land creatures and air creatures. i)

Water creatures: The creatures living in the river, well, pond and sea are known as water creatures. For example, fish, snake, frog, crocodile, etc.

Environment Science –IX 2

ii) iii)

2.

Vegetation Group: All kinds of plants found in the world come under the vegetation group. Different kinds of plants like flower and trees are found in the earth's surface, some plants grow on land and some plants grow in water. The plants which grow on the land are called land vegetation and the plants which grow in water are called water vegetation. ii)

ii)

b)

Land creatures: The creatures living on the land are known as land creatures. For example, man, elephant, cow, crow, horse, etc. Air creatures: The creatures found in the air are known as air creatures. There are various microorganisms in air which we cannot see with our naked eyes. The air creatures have their own environment. The source of survival of these creatures is different from those of water and land creatures.

The Land Vegetation: The trees like mango, oak, Sal, Sisam, apple, etc. are found on land. Different plants like banana, paddy, millet, vegetable, etc. are cultivated by men for their use. These vegetation are land vegetation because they grow on the land. The water Vegetation: The lotus (Kama) Jalkumbhi, Scum (Leu), etc. are found on water surface. The plants which are grown in water are grown in water are called water vegetation. Water environment is necessary for the growth and survival of water vegetation.

Physical or Abiotic Environment The most important physical factors are as follows:

1.

Climatic Factors: The climatic factors include light and heat, temperature, water, humidity, and atmosphere. (a)

(b)

(c)

Light and Heat: Light is an abiotic factor which controls the growth and development of an organism. The sun is the main source of energy. The intensity of light reaching the earth's surface is influenced by atmospheric gases (i.e. nitrogen and oxygen), and suspended particles (i.e. dust and smoke). Radiation from the sun produces direct heating effect and photochemical transformation producing heat energy. Light is essential for all plants and animals except for a few species. It also maintains the temperature of soil, water and atmosphere. Light affects the plant life: in chlorophyll production, heating action, function of stomata, rate of transpiration, distribution of plants, vegetative development of plant parts and succession of plants. Similarly, light has far reaching effects on animals too, by affecting activities such as pigmentation, metabolism, reproduction, development, growth, locomotion, migration, vision and photoperiodism. Temperature: Animals and plants are sensitive to changes in temperature. Changes in temperature may bring positive or negative effects in plant and animal life. Unusual change in temperature may affect the development of forests. There is a close relation between temperature of the environment and geographical distribution of organisms. Temperature influences all biochemical processes in the stages of an organism. Plants and animals can flourish to a variable extent under conditions of temperature fluctuation. These can only be maintained efficiently over a narrow temperature range. For this reason, living organisms must avoid extremes of temperature and somehow accommodate themselves. Aves and mammals have also developed a mechanism for maintaining steady body temperature, so they can live in areas with a wide range of temperature change. Water: Water is vital for living beings. Water occupies about 71 percent of the total surface area of the earth. However, only about 3% water is fresh water and, 97% water is sea-water which is salty. It is in the three states - solid, liquid and gas. Components of Environment 3

(d)

(e)

Water is essential in our daily life. It is needed for cooking food, cleaning purposes, and cooling engines in the industries and the vehicles. It is also needed for irrigation in agriculture production, generation of electricity and keeping the environment clean. It also has a great role in maintaining the human body. The underground water that is available to plants and animals is mainly due to rainfall' In other words, precipitation is the chief source of soil water. This occurs as an interchange of water between the earth's surface and the atmosphere, thus, forming the water cycle. Precipitation occurs in various forms such rain, snow, dew, frost and hail. Water is essential for the existence of almost all living beings. Humidity: It is one of the different forms of water in nature. In atmosphere, water vapour remains in the invisible form which is called humidity. It is greatly influenced by intensity of solar radiation, temperature, altitude, wind exposure, water status of the soil. The daily variation in the relative humidity values depends on the types of habitat conditions. In plains and deserts, it may show variations even during the day. Atmosphere: The main part of the atmosphere is the troposphere (about 20 km above the earth's surface). This is the most important part of the atmosphere for living organisms. In this part, different natural phenomena such as cloud formation, lightning, thundering and thunder storm take place. The moving air is called wind. This is an important environmental factor of the atmosphere as it affects plant life mostly on flat plains and at high altitude mountains. It directly affects the rate of transpiration. It helps in spreading pollen' seeds and fruits. It has direct mechanical effects on vegetation, shelter, soil, and sea. on the other hand, it also causes several types of mechanical damages.

2.

Physiographic Factors: The main physiographic factors are altitude latitude and steepness of slope. With increasing altitude there is decrease in temperature and atmospheric pressure. Steepness of slope affects the angle of insulation on a slope as well as the stability of the land surface. Steepness of a slope affects the amount of solar radiation received during the day. Soil characteristics and steepness of a slope also affect the rate of water flow. The differences in solar radiation and consequent temperature values bring about changes in vegetation on two slopes of a mountain.

3.

Edaphic Factors: Like air and water, soil is also an important factor for plants and animals. Abundance of organisms depends on the soil of the area and its environmental condition. It also depends on the chemical composition of the soil. Generally, plants are found in all types of soil other than in the desert. The composition of soil mainly depends on the type of rock from which it originates. Elements or minerals in soil determine its suitability for sustaining vegetation. Humus contained in soil influences the structure and water holding capacity of the soil. The quantity of humus also determines the acidity or alkalinity (pH) of the soil. Humus provides the substratum that supports micro-organisms, fungi and moulds in the soil. The mechanical breakdown of rock materials into smaller pieces is carried out by the agents such as moisture, and temperature. Similarly, plant roots are also important in splitting the rocks. Besides these, the chemical processes of oxidization, reduction, hydration, hydrolysis and carbonation also play vital roles in soil formation.

1.3.2 Anthropogenic (Socio-economic and Cultural) Factors Human attitude to earth and response to environment have changed through time and still vary between religion and culture. Human impact on the earth is unevenly distributed over the earth's surface. They are trying to change the environment at an accelerated rate to adapt to the environment. Socio-cultural environment consists of everything around us developed by human beings through their tools, skills and social institutions. It comprises a complex society and social activities Environment Science –IX 4

originating from culture. All aspects of culture are the parts of anthropogenic environment. Thus, it includes cropland, buildings, roads and transport, cities, villages, factories, bridges, families, marriage, religions, economy, recreations, entertainment and so on. A society is a closely integrated group of organisms of a species exhibiting division of labour and furnishing protections, continuity, security and identity. Human society has grown out of learned behaviour in the form of traditions, values, morals, customs, folkways, and so on. These are transmitted to the progeny through socialization and other forms of cultural communication. In the long run, it gets established and takes the shape of social institutions such as family, religion, culture, education and economy. (a) Family: Family is a unit of a community consisting of individuals produced after marriage. Marriage is a relationship which continues the human race. The system and the norms of marriage may vary from community to community. The size, composition and tradition of a family also affect the environment. (b) Religion: Religion comprises devotional, ritual observances, and a moral code for the conduct of human beings. It also includes institutionalized beliefs and practices. These are generally accepted by a number of persons. It is a force that determines the social attitudes and values. Religions influence people to live in harmony with the environment. (c)

Culture: A society is also shaped by its history. These are the events, achievements and experiences of the past, in regard to the institutions and activities. So, the study of history is also important in understanding the culture of a society and community. The evidences of the achievements and activities of the past are the archaeological objects which form the rich human heritage. Cultural tradition has played its part in determining people's attitudes towards the environment. People have a unique aesthetic sense which gives rise to another dimension of the cultural activity. Through this activity people seek to get mental satisfaction and relief. They have been trying to make environmental settings in keeping with the aesthetic taste and the sense of beauty.

(d) Education: In the broadest sense, education is the strongest means of transmission of cultural heritage. Education not only influences attitudes and values but also sets up powerful instrument of social progress. It is a powerful tool for modifying the environment. (e)

Economy: Humans have developed agricultural and industrial practices. This important social institution relates to the production, distribution and use of commodities, resources, income and wealth.

1.4. Need and Importance of Environment Education Environment education gives spirit to man and the community to create awareness of the environment. It gives the knowledge, idea and skill to man about the environment. It gives an idea of how nature works. It also provides knowledge on biological, physical, social, cultural and economic environment. Besides, people acquire skills of identifying and solving environmental problems. The environmental education helps to develop attitude for active participation in the environmental promotion and conservation. Environmental Education teaches people to make proper use of various things found in the environment. As people become aware of the importance of the environment, they will realize the importance of wildlife and green vegetation; they will also realize the importance of their cultural heritage and the need of family planning for a happy life. Environmental education develops knowledge, skills and attitude of individual for the conservation of various aspects of the environment. It guides us how to manage the environment Components of Environment 5

properly and how to use sustainable environmental resources. It teaches us the basic principles of environmental conservation. Environmental education develops concept of wise-use in individual, which helps in conservation of the environment. It also provides us knowledge of preservation of environmental aspects and also encourages us to take necessary action for their preservation. The importance of environment education can be summarized as follows: 1. Environment education provides knowledge about the relationship between and the nature. 2. It provides the knowledge of natural and artificial things on the earth. 3. It gives the knowledge of family, house, school, town and village along with individual's relationship with them. 4. It denotes exclusive relationship among creatures, vegetation and non-living things. 5. It denotes positive and negative effects of human activities on nature and their mutual dependence. 6. It develops vision of unity and softness to look into the earth from global to local levels 7. It teaches to make the best use of the environment which develops skill in man to pass quality of life. 8. It brings improvement in the behavior of man with natural resources and its management. 9. It enables man to take responsibility to transfer the neat and clean earth for further generation. 10. It provides comprehensive knowledge to know the nature and its proper use. 11. It arouses awareness in people for the preservation of the environment. 12. It imparts knowledge, skills and attitude to conserve the different components of the environment like land, water, forest and wildlife. 13. It emphasizes the protection and conservation of wildlife, natural sites' cultural sites and archaeological places. 14. It teaches us how the preservation of the environment and construction development works can go together. 15. It teaches us to care and respect all the things of the nature that contribute to the conservation of nature. 16. It helps to raise the awareness in wise use of environmental resources, protection and their proper utilization. 17. It encourages us to integrate the conservation efforts into the development activities that help to establish a system of environmental conservation. 18. It teaches us various aspects of environment such as biological, physical, natural and socio-cultural. 19. It develops our knowledge and skill in proper use of the environmental resources such as land, water, Plants and its products that contribute to the conservation of the environment. Hence, Environmental Education teaches people how to make human life healthier and happier by maintaining a clean, green and healthy environmental.

EXERCISE A)

Very short questions: 1) 2) 3) 4) 5)

Define environment? Define environment education. State one element of environment? State one anthropogenic element of environment. What does edaphic factor of environment?


B)

c)

Short questions 1) What is environment? 2) Draw a chart showing elements of environment. 3) Describe briefly the physiographic factors of the environment. 4) Describe the importance of environment education 5) Describe physical components of the environment. Long questions 1) 2) 3) 4)

Define environment. Draw a chart showing components of environment and explain any one of the component in detail. Explain the components of the environments in brief? Describe the components of biological environment? What is environment education? Explain importance of environment education?

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UNIT Ecology and Ecosystem 2.1 Introduction An ecosystem is defined as the interrelationship between living and non-living things of the atmosphere. It is a community of living organisms (plants, animals and microbes) in conjunction with the nonliving components of their environment (things like air, water and mineral soil), interacting as a system. These components are regarded as linked together through nutrient cycles and energy flows. As ecosystems are defined by the network of interactions among organisms, and between organisms and their environment, they can come in any size but usually encompass specific, limited spaces (although it is sometimes said that the entire planet is an ecosystem). Ecosystems are controlled both by external and internal factors. External factors such as climate, the parent material which forms the soil and topography, control the overall structure of an ecosystem and the way things work within it, but are not themselves influenced by the ecosystem. Other external factors include time and potential biota. Ecosystems are dynamic entities—invariably, they are subject to periodic disturbances and are in the process of recovering from some past disturbance. Ecosystems in similar environments that are located in different parts of the world can end up doing things very differently simply because they have different pools of species present. The introduction of non-native species can cause substantial shifts in ecosystem function. Internal factors not only control ecosystem processes but are also controlled by them and are often subject to loops. While the resource inputs are generally controlled by external processes like climate and parent material, the availability of these resources within the ecosystem is controlled by internal factors like decomposition, root competition or shading. Other internal factors include disturbance, succession and the types of species present. Although humans exist and operate within ecosystems, their cumulative effects are large enough to influence external factors like climate. Arthur G. Tansley, a British ecologist, was the first person to use the term "ecosystem" in a published work. Tansley devised the concept to draw attention to the importance of transfers of materials between organisms and their environment. He later refined the term, describing it as "The whole system, including not only the organism-complex, but also the whole complex of physical factors forming what we call the environment". The word ecology is derived from the Greek word ‘oikos’ means house. Ecology is the branch of biology which deals with the study of the relationship between the organisms and the environment. So, ecosystem is the functional unit of the Ecology. Ecology was coined by a German biologist in 1869 AD.

2.1.1 Components of the ecosystem An ecosystem consists of two types of components- abiotic and biotic. The biotic components are living beings; they are often distinguished into autotrophy and heterotrophy. Autotrophy is also called producers. Heterotrophy is of four types- consumers (herbivores and carnivores), parasites, scavengers (detritovores) and decomposers. The abiotic components include non-living inorganic substances, organic substances, etc. Environment Science –IX 9

A.

Abiotic Components

1.

Inorganic Substances: They include water (hydrosphere), minerals (lithosphere) and gases (atmosphere). The inorganic substances required for the synthesis of organic substances are called inorganic nutrients or biogenetic substances. The nutrients keep on circulating in the ecosystem. They are picked up by the producers, passed on to the consumers and are transferred back to physical environment through the activity of detritus feeders.

2.

Organic Substances They are substances dispersed from the dead bodies of organisms or are derived from their excretions. The various organic substances are collectively called organic detritus. The important ones are amino acids, proteins, lipids, carbohydrates, etc. The organic compounds contain mineral nutrients in the bound form. They are acted upon by decomposers to release the minerals. The organic substances link the biotic components of the ecosystem with the abiotic components.

3.

Climate It is a complex term which is derived from the interaction of available solar radiations with rocks water, gases etc. to produce a number of variables like heat, light, rain, wind, dusk, Strom, fire, fog, moist, snow, etc. Climate of an area determines the number of producers it can hold, the number of consumer, the degree of detritus removal and hence circulation of nutrients.

B.

Biotic Components Biotic components are divided into two components from the functional view point: i) Autotrophic components- it consists of green plants which bring about the fixation of solar energy and synthesis of organic compounds (carbohydrates) from the inorganic constituents derived from the soil. ii) Heterotrophic component- it consists of the living organism like decomposers and consumers which are concerned with utilization, rearrangement and degradation of complex food substances produced by autotrophic components. The organisms involved are known as consumers which are further categorized into primary, secondary and tertiary consumers. Thus, from a general view point, the ecosystem has three important components in the biotic environment.

Different biotic Components 1.

Producers These are the autotrophic groups of the ecosystem. They have chlorophyll. In the presence of the sunlight, they can make their food by using inorganic compounds. This process is known as photosynthesis. In an ecosystem, the producers may be represented by small microscopic plants and algae or the rooted or large floating plants generally growing in shallow plants in pond water and lakes, the algae in the ocean are the examples of producers. Since all these plants produce food for all the other organisms, they are known as producers. 2. Consumers Consumers are heterotrophic organisms which consume the food produced by producers. These are chiefly the animal of different kinds found in an ecosystem. These consumers consume different categories such as primary, secondary and tertiary. Herbivores are dependent upon green plants for their food and are known as primary consumers. A deer or rabbit is a primary consumer in a forest and a rat in a garden; protozoan’s, crustaceans and mollusks which feed on floating algae found in ponds Components of Environment 10

or lakes or sea are also primary consumers in their respective habitats. Secondary consumers are those who use the primary consumer for food. They are primary carnivores or omnivores animals such as wolves, dogs, cats, foxes, etc. from the terrestrial environment and large fish and snakes from the aquatic environment. Tertiary consumers are that animals which feed on primary carnivores or they are also known as secondary carnivores. For example- lions, which feed upon the wolves, cattle, deer etc., are secondary carnivores. 3. Decomposers These are also biotic components of the ecosystem and are largely composed of microorganisms such as bacteria, fungi, virus, protozoan which feed upon dead and decaying living organisms both plants and animals and they break them into simple compounds. These are released free in the soil and atmosphere and are utilized by the producers for the synthesis of their food materials.

2.2

Terrestrial Ecosystem:

A terrestrial ecosystem is an ecosystem found only on landforms. Terrestrial ecosystems are distinguished from aquatic ecosystems by the lower availability of water and the consequent importance of water as a limiting factor. Terrestrial ecosystems are characterized by greater temperature fluctuations on both diurnal and seasonal basis, the greater availability of light and different gases than in aquatic ecosystems. Those gases include carbon dioxide that serves as a substrate for photosynthesis, oxygen that serves as a substrate in aerobic respiration, and nitrogen that serves as a substrate for nitrogen fixation. Terrestrial environments are segmented into a subterranean portion from which most water and ions are obtained, and an atmospheric portion from which gases are obtained and where the physical energy of light is transformed into the organic energy of carboncarbon bonds through the process of photosynthesis. Terrestrial ecosystems occupy 144,150,000 km2, or 28.2%, of Earth's surface. Major plants in terrestrial ecosystems are flowering plants, of which there are about 275,000 species, and the division conifers, of which there are about 500 species. Members of the division Bryophyta (mosses and liverworts), of which there are about 24,000 species, are also important in some terrestrial ecosystems. Major animals in terrestrial ecosystems include the classes Insecta (insects) with about 900,000 species, Aves (birds) with 8500 species, and Mammalia (mammals) with approximately 4100 species. Major terrestrial ecosystems are discussed below:

2.2.1 Forest Ecosystem Predominant vegetation of this ecosystem is trees, spread with a large number of species of herbs, shrubs, climbers, lichens, algae and a wide variety of animals. The forest is composed of trees, shrubs or any other woody vegetation. Forest occupies roughly 40% of the land The forest ecosystem is of great concern from the environmental point of view Different components of this ecosystem are as follows: Abiotic Component: These are inorganic as well as organic substances present in the soil. In addition to minerals, some dead organic materials are also present in the soil. Biotic Component: The living organisms present in the food chain occur in the following order: 1.

Producers: They include trees, climbers, epiphytes, shrubs and ground vegetation.

2.

Consumers: (a) Primary Consumers: These are herbivores. They include tree-leaf feeding small animals such as ants, flies, beetles, leaf hoppers, bucks, spiders, and other insects. Similarly, they also include larger grazing animals such as deer, neelgai, elephants, rabbits, monkeys, moles, squirrels, shrews, flying foxes, fruit bats, mongoose, and so on.


3.

(b)

Secondary Consumers: These are carnivores that feed on herbivores. They include animals such as snakes, lizards, foxes, wolves, jackals and birds.

(c)

Tertiary Consumer: These are the top level carnivores that feed on secondary consumers. They include animals such as lions and tigers.

Decomposers: These are also living components of the community. They mostly include microorganisms such as bacteria and fungi. These act on dead bodies of producers and consumers and are responsible for breaking up complex materials into simpler substances.

2.2.2 Tropic Level A source of food in each step of food chain is called tropic level The green plants are the producers, and they constitute the first tropic level. The producers are consumed by the herbivores animals and they constitute the second tropic level. The carnivores forms the third tropic level. The animals that feed upon herbivores are called carnivores. The animals that feed upon small carnivores are called top carnivores. They constitute the 4th tropic level.

Tertiary consumer (Fourth Tropic level) Secondary consumer (Third tropic level)

Primary consumer (Second tropic level) Producer (First tropic level)

2.2.2 Energy Flow in an Ecosystem In a food chain, the energy flows from one trophic level to another in a decreasing trend. It means, each trophic level in a food chain contains a certain amount of biomass i.e. the dry weight of all organic matter contained in organisms. Chemical energy stored in biomass is transferred from one trophic level to another. The percentage of usable energy transferred as biomass from one trophic level to another is called ecological efficiency. It ranges from2% to 40% (it means, there is a loss of 60-98%) depending on the types of species and the ecosystem involved, but 10% is normally typical. Assuming 10% ecological efficiency (i.e. 90% loss) at each trophic level transfer, if green plants in an area manage to capture 10,000 units of energy from the sun, then only about 1,000 units of energy will be available to support herbivores and ultimately only about 100 units of energy will be available to support carnivores. The more the trophic levels or steps in a food web, the greater the cumulative loss of usable energy flows through the various trophic levels. Energy flow pyramids explain why the earth can support more people if they eat at lower trophic levels by consuming grains, vegetables, and fruits directly rather than passing such crops through another trophic level and eating grain eaters such as cattle. Components of Environment 12

Omnivores Omnivores Carnivores Herbivores Producers

A large loss in energy between successive trophic levels also explains why food chains and food webs rarely have more than four or five trophic levels. In most cases, too little energy is left after four or five transfers to support organisms feeding at these high trophic levels. As a result, there are relatively few top carnivores such as eagles, hawks, tigers, and white sharks.

2.3 Mountain Ecosystem High elevation of land is called a mountain. It is normally covered with snow. There also exists a typical terrestrial ecosystem. A mountain region exists at high altitude and can be called an alpine biome. The alpine zone refers to the region of a mountain above the tree line and this zone contains certain plants and animals. The alpine zone includes a sub-snow zone, a meadow zone and a shrub zone. High altitude environment is characterized by low air density and low levels of oxygen and carbon dioxide. The snow cover increases the rate of desiccation and high wind velocity. Alpine zone in the mountains is characterized by a sparseness of animal groups. Mountain ecosystem refers to the ecosystem at high elevations on mountains, above the forest line (tree line) altitude of 3500 m. The disappearance of forest is the main effect of altitude as it is too cold for the growth of trees. High altitude is a region of progressively semi-attenuated air. A11 other environmental conditions which characterize mountain systems are the secondary effects of low atmospheric pressure compared to all other environments. The mountain ecosystem also includes various components which are as follows: Abiotic Component: This includes aerial environment consisting of gases like CO 2, 02, and others like temperature, light, and water. There are also organic and inorganic constituents of the soil which are included in the abiotic component. Similarly, inorganic compounds such as water, calcium, phosphate, and their compounds, nitrates, carbonates, phosphorous, are also available there. Biotic Components 1. Producers: Plants are ecologically highly specialized. They may be dwarf and branched. Perennial herbs include Acoinitum, Amemone, and so on. Cushion plants include Arenalia, Gypsophila, and others. There are also shrubs, some kinds of grass and a few trees in the coniferous forests which adjoin the southern part of the alpine zone (hemlock, pine, fir, etc.). 2. Primary consumers: The most common animals are the Tibetan sheep (Ovis liodgsoni), punir sheep (Ovis poli), Tibetan yak (Bos grunnius) and Persian wild goat (Capra aegagrus), which live in high altitudes. The biotic component also includes a wide range of lower animal species such as protozoa, helminthes, molluscs and arthropods (insects and spiders). 3. Secondary consumers: These include some migrant birds from the lowlands, such as the snow partridge (Lerwa nivicola). Some of the vertebrates are crow (Corvus corax), snow leopard (Felis unica), and so on. Environment Science –IX 13

4.

Decomposers: There are some fungi and bacteria in the forest and desert region connected to the mountain region.

Trophic Levels The trophic levels of the mountain ecosystem are as follows: First trophic level : It includes producers. They are small grasses, other small plants, bacteria, etc. Second trophic level : It includes primary consumers or herbivores. They are sheep, yak, wild goat, etc. Third trophic level : It includes tertiary consumers or omnivores, for example - human beings. Fourth trophic level : It includes decomposers or microorganisms.

EXERCISE A)

Very short questions: 1) 2) 3) 4) 5) 6) 7) 9) 10)

Define ecology. Define ecosystem. Who use the term ecosystem in the first time? What is producer? Give example Give the example of any abiotic component of ecosystem. Give example of any one decomposer. List out the abiotic component of forest ecosystem. Define trophic level. Give example of 2nd trophic level of mountain ecosystem?

B.

Short answer questions. 1) Define ecology and ecosystem with examples. 2) List the different constituents of ecosystem and explain any one of them. 3) Define trophic level. Draw a diagram showing different trophic level. 4) Explain the trophic level of forest ecosystem. 5) Explain the trophic level of mountain ecosystem.

C.

Long answer questions. 1) What is ecosystem? Explain forest ecosystem with its different constituents in detail. 2) What is terrestrial ecosystem? Explain mountain ecosystem with its different constituents in detail. 3) What is trophic level? Describe the energy flow in forest ecosystem.

D.

Practical Problems 1) Visit a forest area and write a report on forest ecosystem. 2) Visit a nearby mountain area and make a report on mountain ecosystem. A report must contain following contents  Introduction to the location and study  Objectives  Methodology  Observation of the subject matter and reasons  Conclusion and recommendations




UNIT Environmental pollution 3.1 Pollution Pollution is the introduction of a contaminant into the environment. It is created mostly by human actions, but can also be a result of natural disasters. Pollution has a detrimental effect on any living organism in an environment, making it virtually impossible to sustain life. Polluted environment consists of solid wastes, polluted water, disease germs, diseased plants and animals, etc. The area covered by the pollution is going on increasing. The polluted environment has been degrading the healthy environment. Such places are not suitable to live in; sometimes people are forced to migrate somewhere. Because humans are at the top the food chain, they are particularly vulnerable to the effects of non-degradable pollutants.

Types of Pollution Generally, the classification of pollution is made on the basis of environment in which it occurs, viz, air water and land pollution. Sometimes it is classified on the basis of pollutants which is the causative agent, viz, sound, thermal, radioactive pollution, etc.

3.2

Water pollution

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater). Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds. It is defined as the addition of any substances to water or changing of water’s physical and chemical characteristics in any way which interferes with its use for legitimate purposes. Normally, water is never pure in a chemical sense. It contains impurities of various kinds-dissolved as well as suspended. These include dissolved gases (H2S, CO2, NH3, N2, dissolved minerals (Ca, Mg, Na, and salts), suspended matter (clay, silt, sand) and even microbes. These are natural impurities derived from atmosphere, catchment areas and the soil. They are in very low amounts and normally do not pollute water and it is potable. Polluted water is however, do turbid unpleasant, bad smell, unfit for drinking, washing or other purposes. It is harmful and is vehicles of many diseases as cholera, dysentery, typhoid etc.

3.2.1 Sources of water pollution Different sources of water pollution are 1.

Petroleum Products Oil and chemicals derived from petroleum substances are used for fuel, lubrication, plastics manufacturing and many other purposes. These petroleum products get into water mainly by means of accidental spills from ships, tankers, trucks, pipelines and leaky underground storage tanks. Many petroleum products are poisonous if ingested by animals. Spilled oil damages the features of birds or fur of animals often causing death. In addition, spilled oil may be contaminated with other harmful substances, such as polychlorinated biphenyls (PCB s). Components of Environment 15

2.

Pesticides and Herbicides

Chemicals used to kill pets and weeds, for instance, in farms or in suburban yards, may be collected by rainwater runoff and carried into streams, especially if these substances are applied too lavishly. Some of these chemicals are biodegradable and quickly decay into harmless or less harmful forms, while others are non-biodegradable and remain dangerous for a long time. When animals consume plants that have been treated with certain non-biodegradable chemicals, such as, chlordane and Dichlorodiphenyl trichloro ethane (DDT), these chemicals are absorbed into the tissue or organs of the animals. When other animals feed on these contaminated animals, the chemicals are passed up the food chain. With each step of the food chain, the concentration of the pollutant increases. In one study, DDT levels in ospreys (a family of fish-eating birds) were found to be ten to fifty times higher than in the fish that they ate, 600 times the level in the plankton that the fish ate, and ten million times higher than in water. Animals at the top of food chains may, as a result of these chemical concentrations, suffer cancers, reproductive problems and death. Many drinking water resources and supplies are contaminated with pesticides from widespread agricultural use. More than fourteen million Americans drink water contaminated with pesticides and the Environmental Protection Agency (EPA) estimates that ten percent of wells contain pesticides. Nitrates, a pollutant often derived from fertilizer runoff, can cause methemoglobinemia in infants, a potentially lethal form of anemia i.e. also called blue body syndrome. 3.

Heavy Metals

Heavy metals, such as copper, lead, mercury and selenium, get into water from many sources including industries, automobile exhaust, mines and even natural soil. Like pesticides, heavy metal become more concentrated as animals feed on plants, which are, in turns, consumed by other animals. When they reach high levels in the body, heavy metals can be immediately poisonous or can result in long-term health problems similar to those caused by pesticides and herbicides. For example, cadmium in fertilizer derived from sewage sludge can be absorbed by crops. If these crops are eaten by humans, the metal can cause diarrhea and vomiting, liver and kidney damage. Lead can get into water from lead pipes and solder in older water pipe systems; children exposed to lead in water can suffer mental retardation. 4.

Hazardous Wastes

Hazardous wastes are chemicals wastes that are toxic, reactive, corrosive or ignitable (flammable). If improperly treated or stored, hazardous wastes can pollute water supplies. In 1969, the Cuyahoga River in Cleveland, Ohio, was so polluted with hazardous wastes that it caught fire and burned. PCBs, a class of chemicals and once widely used in electrical equipment such as transformers can get into the environment through oil spills and can reach toxic levels as organisms eat one another. 5.

Excess Organic Matter

Fertilizers and other nutrients used to promote plant growth on farms and in gardens may find their way into water. At first, these nutrients encourage the growth of plants and algae in water. However, when the plant matter and algae die and settle under water, microorganisms decompose them. In the process of decomposition, these microorganisms consume oxygen that is dissolved in water. Oxygen levels in the water may drop to such dangerously low levels that oxygen-dependent animals in the water, such as fish, may die. This process of depleting oxygen to deadly levels is called eutrophication. 6.

Sediments

Sediments, soil particles carried to a stream bed, lake or ocean can also be pollutants if they are present in a large amount. Soil erosion produced by the removal of soils trapping trees near water ways, or carried by rain water and flood water from crop plantations, strip mines and roads can Components of Environment 16

damage a stream or lake by introducing too much nutrient matter. This leads to eutrophication. Sedimentation can also cover stream bed gravel in which many fishes such as salmon and trout lay their eggs. 7.

Infectious Organisms A 1994 study by the center for disease control prevention (CDC) estimated that about 9, 00,000 people get sick unusually in the United States because of organisms in their drinking water and around 900 people die. Many diseases organisms that are present in small members in most natural water are considered pollutants when found in drinking water. Such parasites as Giardia, lamblia and Cryptosporidium parvum occasionally turn up in urban water supplies. These parasites can cause illness, especially in people who are very old or very young and in people who are already suffering from other diseases. 8.

Thermal Pollution

Water is often drawn from rivers, lakes or oceans for the use as a coolant in factories and power plants. Such water is usually returned to the source warmer than it was taken. Even a small temperature changes in a body of water can drive away the fish and other species that are originally present and attract other species in place of them. Thermal pollution can accelerate biological processes in plants and animals or deplete oxygen level in water. The result may be death of fish and other wildlife near the discharge source. Thermal pollution can also be caused by the removal of trees and vegetation that shade and cool streams.

3.2.2 Water pollutants Pollutants include organic and inorganic substances. Organic water pollutants include           

Detergents Disinfection by-products found in chemically disinfected drinking water, such as chloroform Food processing waste, which can include oxygen-demanding substances, fats and grease Insecticides and herbicides, a huge range of organohalides and other chemical compounds Petroleum hydrocarbons, including fuels (gasoline, diesel fuel, jet fuels, and fuel oil) and lubricants (motor oil), and fuel combustion byproducts, from storm water runoff Volatile organic compounds (VOCs), such as industrial solvents, from improper storage. Chlorinated solvents, which are dense non-aqueous phase liquids (DNAPLs), may fall to the bottom of reservoirs, since they don't mix well with water and are denser. Polychlorinated biphenyl (PCBs) Trichloroethylene Perchlorate Various chemical compounds found in personal hygiene and cosmetic products.

Inorganic water pollutants include      

Acidity caused by industrial discharges (especially sulfur dioxide from power plants) Ammonia from food processing waste Chemical waste as industrial by-products Fertilizers containing nutrients--nitrates and phosphates—which are found in storm water runoff from agriculture, as well as commercial and residential use Heavy metals from motor vehicles (via urban storm water runoff) and acid mine drainage Silt (sediment) in runoff from construction sites, logging, slash and burn practices or land clearing sites. Components of Environment 17

Macroscopic pollutants—large visible items polluting the water—may be termed "floatables" in an urban storm water context, or marine debris when found on the open seas, and can include such items as: 

Trash or garbage (e.g. paper, plastic, or food waste) discarded by people on the ground, along with accidental or intentional dumping of rubbish, that are washed by rainfall into storm drains and eventually discharged into surface waters Small ubiquitous waterborne plastic pellets Shipwrecks, large derelict ships.

 

Effects of Water Pollution 1.

2. 3. 4. 5.

6. 7. 8. 9.

Domestic wastes and sewage contains many micro-organisms or disease causing agents which may cause typhoid, cholera, dysentery, jaundice, itching etc. such organisms also utilize dissolved oxygen of water which directly affects other aquatic animals. Domestic wastes and sewage create foul smell which makes water unfit for many purposes. It also increases algal blooms due to which organic matter is increased. Inorganic compounds of nitrates and phosphates increase the rate of eutrophication. Detergents from washing and bathing are slow degrading substances; hence the effect of which remain for long periods. Thermal pollution increases water temperature and the hot water can hold less oxygen. It changes life in water. While trout eggs cannot produce fingerlings due to failure in hatching, they are reduced. Oil, when spread over surface of water, decreases its oxygenation so that aquatic animals are badly affected. It may catch fire and harm all organisms in water. It kills sea birds. Muddy water caused by run water cut off sunlight for submerged plants. This causes reduction in dissolved oxygen which ultimately leads to the reduction of aquatic organisms. Cadmium obtained by industries causes kidney damage, hypertension, anemia and damage to placenta. Compounds of lead and mercury are slow poisonings which cause skin diseases, anemia, headache, loss of muscular power and irreversible brain damage.

3.2.4 Controlling measures of water pollution Water pollution prevention and control measures are critical to improving water quality and reducing the need for costly wastewater and drinking water treatment. Because water pollution can come from many different sources, a variety of pollution prevention and control measures are needed. Some of the ways to control water pollution are as follows: 1.

2. 3. 4. 5.

Use of pesticides and insecticides should be controlled or reduced. In such chemicals, degradable and less stable materials should be used so that toxic effect would be prevailing. Hot effluents from industries should be controlled before disposing to the hot water body. Domestic wastes should be converted into compost rather than throwing into the sources of water. Toxic substances of sewage pollutants should be converted into non-toxic substances by treatment. Water hyacinth is a biological mean to reduce water pollution. It can also filter out heavy metals like lead, mercury, cadmium and toxic substances. Components of Environment 18

6.

7. 8. 9. 10. 11. 12. 13.

There should be provision of monitoring effluents from industries before mixing them in the water body. Some rules should be created and enforced to treat such wastes to a certain standard before releasing them. Soil erosion, floods and landslides are to be controlled so that sources of water may not be polluted. People’s awareness should be developed regarding polluted water which has adverse effects on the health of the living creatures. Banning or more strictly regulating disposal of hazardous waste in deep injection wells and landfills. Planting buffers zones of vegetation between cultivated fields and nearby surface water. Controlling human pollution. Banning on nuclear test. Managing solid waste and liquid waste properly.

3.2.5 Water Purification Water purification is the process of removing undesirable chemicals, material and biological contaminants from raw water. The goal is to produce water fit for a specific purpose. Water is mostly purified for human consumption (drinking water); however, purification may also be designed for variety of other purposes, including meeting the requirements of medical pharmacology, chemicals and industrial applications. In general, the methods used include physical processes such as filtration and sedimentation, biological processes such as slow sand filters or activated sludge, chemical processes such as flocculation and chlorination and the use of electromagnetic radiation such as ultraviolet light. The purification processes of water may reduce the concentration of particular matter including suspended particles, parasites, bacteria, algae, viruses, fungi and a range of dissolved and particulate materials derived from the surface that the rain water might have come in contact with. 1.

Flocculation Flocculation is a process which clarifies water. Clarifying means removing any turbidity or colour from water. Clarification is done by causing a precipitate to form in the water, which can be removed using simple physical methods. Initially, the precipitate forms a very small particles but as the water is gently stirred, these particles stick together to form bigger particles. This process is sometimes called flocculation.

2.

Sedimentation Water exiting the flocculation basin may enter the sedimentation basin, also called a clarifier or settling basin. It is large tank with slow flow, allowing flock to settle to the bottom. The sedimentation basin is best located close to the flocculation basin so that the transit between does not permit settlement or flock break up. Sedimentation basins can be in the shape of a rectangle where water flows from end to end or circular where flow is from the centre outward. Sedimentation basin outflow is typically over a weir; so, only a thin top layer – furthest from the sediment-exists.

3.

Boiling Boiling kills bacteria as well as other disease-causing microorganisms like Giardia,lamblia and Cryptosporidium parvum which are commonly found in rivers and lakes. Water temperature above 70oC will kill all pathogens within 30 minutes, above 85 0C within a few minutes, and at boiling point (1000C), most pathogens will be killed, excluding certain pathogens and their spores, which must be heated to 118 degree Celsius (e.g.: botulism – Clostridium botulinum). Components of Environment 19

This can be achieved by using a pressure cooker because regular boiling will not heat water past 1000C. 4.

Filtration Portable pump filters are commercially available with ceramic filters that filter 5,000 to 50,000 liters per cartridge, removing pathogens down to the 0.2-0.3 micrometer range. Some also use activated charcoal filtering. Filters of this kind remove most bacteria and protozoa, such as Cryptosporidium parvum and Giardia,lamblia, but not viruses except for the very largest of 0.3 micrometer and largest diameters. So, disinfection by chemicals or ultraviolet light is still required after filtration.

5.

Chlorination The most common disinfection method involves some form of chlorine or its compounds such as chloramines or chlorine dioxide. Chlorine is a strong oxidant that rapidly kills many harmful micro-organisms. Because chlorine is a toxic gas, there is a danger of release associated with its use. This problem is avoided by the use of sodium hypochlorite, which is relatively inexpensive solution that releases free chlorine when dissolved in water. Chlorine solutions can be generated on site by electrolyzing common salt solutions.

6.

Solar water disinfection (SODIS) In solar water disinfection (SODIS), microbes are destroyed by temperature and UVA radiation provided by the sun. Water is placed in a transparent plastic PET bottle, which is first oxygenated by shaking partially-filled capped bottles prior to filling the bottles all the way. The completely water-filled and capped bottles are exposed to sunlight, preferably on a corrugated metal roof, slanted slightly to maximize the exposure to solar radiation. In practice, the waterfilled bottles are placed for six hours in full sun or for two days in partial sunlight for weather conditions involving partially overcast days, which raises the temperature of the water and give an extended dose of solar radiation to the water in the bottles, killing almost all microbes present in it. The combination of the two effects (UVA and heat) provides a simple method of disinfection for use in tropical developing countries, or in survival situations.

3.3 Quality of Air Air without any pollutants cannot be imagined because it means-stopping all kinds of pollutants by pausing industrial and other activities. If the pollution level on other hand becomes too high, then it starts causing harmful effects in humans, other animals and ecosystem as a whole. So, the government establishes a level of pollutants that should prevail in the atmosphere and the level that should not be exceeded. This maximum limit of allowable concentration of pollutants is termed as Air Quality Standards. The constituents of atmosphere by volume are as follows: Gases 1. 2. 3. 4. 5. 6. 7. 8.

Volume % (Dry Air) Nitrogen (N2) Oxygen (O2) Argon (Ar) Carbondioxide (CO2) Neon (Ne) Helium (He) Ozone (O3) Hydrogen (H2)

78.08 20.94 0.93 0.03 0.0018 0.000524 0.000001 0.00005 Components of Environment 20

9. 10. 11.

Krypton (Kr) Methane (CH4) Nitrous Oxide (N2O)

0.000114 0.0002 0.00005

There are two types of standard: ambient standard and emission stand: Ambient standard defines the permissible levels of particular pollutants that exist in the air, and, are usually set so that no harm to human health is expected at those levels. Emission standard is designed to control emissions from specific sources of pollution, with the goal of reducing overall emission to levels such that ambient air quality is below those specified in the ambient standards.

3.4 Air pollution Air pollution is an addition of harmful substances to the atmosphere resulting in damage to the environment, human health, and quality of life. A normal man breathes nearly 22,000 times a day inhaling about 16 kg air. One of many forms of pollutions, air pollution occurs inside offices, in cities, across continents, and even globally. Air pollution makes people sick; it causes breathing problems and promotes cancer and it harms plants, animals and the ecosystem in which they live. Some air pollutants return to earth in the form of acid rain and snow, which corrode statue and buildings, damage crops and forests and make lakes and streams unsuitable for fish and other plants and animal life. Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere.

3.4.1 Sources of air pollution Sources of air pollution refer to the various locations, activities or factors which are responsible for the releasing of pollutants into the atmosphere. Major air pollutants are : Sulphur oxides (SOx) Nitrogen oxides (NOx) Carbon monoxide (CO)-Carbon dioxide (CO2) Volatile organic compounds – like methane (CH4) ,aromatic compounds benzene, toluene and xylene, Toxic metals, such as lead, cadmium and copper, Chlorofluorocarbons (CFCs), Ammonia (NH3) ,Ground level ozone etc. These sources can be classified into two major categories which are: Anthropogenic sources (human activity) : Mostly related to burning different kinds of fuel. They can be summarized as:  "Stationary Sources" include smoke stacks of power plants, manufacturing facilities (factories) and waste incinerators, as well as furnaces and other types of fuel-burning heating devices. In developing and poor countries, traditional biomass burning is the major source of air pollutants; traditional biomass includes wood, crop waste and dung. 

"Mobile Sources" include motor vehicles, marine vessels, aircraft effect of sound etc.



Chemicals, dust and controlled burn practices in agriculture and forestry management. Controlled or prescribed burning is a technique sometimes used in forest management, farming, prairie restoration or greenhouse gas abatement. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for foresters. Controlled burning stimulates the germination of some desirable forest trees, thus renewing the forest.



Fumes from paint, hair spray, varnish, aerosol sprays and other solvents



Waste deposition in landfills, which generate methane. Methane is not toxic; however, it is highly flammable and may form explosive mixtures with air. Methane is also an asphyxiant and may displace oxygen in an enclosed space. Asphyxia or suffocation may result if the oxygen concentration is reduced to below 19.5% by displacement



Military, such as nuclear weapons, toxic gases, germ warfare and rocketry Components of Environment 21

 

Automobile exhausts contains carbon monoxide, oxides of nitrogen, ethylene, benzyrene, etc. These gases are produced due to incomplete combustion of petrol and diesel. Industrial Exhausts: The industries mainly chemical factories, paper and pulp factories, sugar factories, petroleum refineries and steel plants are the chief air polluting agents. They release carbon monoxide (CO), carbon dioxide (CO2), sulphur dioxide (SO2), nitric oxide (NO), nitrous oxide (N2O), chlorine (Cl2), fluorine (F), water vapour, ammonia (NH3), etc. in addition to particulate matter.

Natural sources 

Dust from natural sources, usually large areas of land with little or no vegetation



Methane, emitted by the digestion of food by animals, for example cattle



Radon gas from radioactive decay within the Earth's crust. Radon is a colorless, odorless, naturally occurring, radioactive noble gas that is formed from the decay of radium. It is considered to be a health hazard. Radon gas from natural sources can accumulate in buildings, especially in confined areas such as the basement and it is the second most frequent cause of lung cancer, after cigarette smoking



Smoke and carbon monoxide from wildfires



Vegetation, in some regions, emits environmentally significant amounts of VOCs on warmer days. These VOCs react with primary anthropogenic pollutants—specifically, NOx, SO2, and anthropogenic organic carbon compounds—to produce a seasonal haze of secondary pollutants.



Volcanic activity, which produce sulfur, chlorine, and ash particulates

3.4.2 Effects of Air Pollution It is a known fact that air pollution affects the climate in a major way. It is also reduces visibility causing by traffic hazards. In addition, there are major effects caused by air pollution which will be described in brief: i.

ii.

iii.

Atmospheric particles can scatter and absorb sunlight and reduce the visibility. Reduce visibility is aesthetically undesirable and it is also dangerous for aircrafts and motors. In general, cities receive above 15 to 20% less solar radiations than rural areas and the reduction of sunlight can become as high as one-third in the summer and two-third in winter. The reduction in sunlight is largely due to fuel combination for industrial and household heating purposes. The effects of particulate matter include corrosion of metals, corrosion and soiling of buildings, sculptures and painted surfaces and soiling of clothing and draperies, damage of electric equipment, etc. The toxic effects of particulate matter on animals and human beings can be classified as: a. Intrinsic toxicity due to chemicals or physical properties: carbon monoxide in congested areas removes 5 to 10% of blood from circulation. Although body tissues extract only 20% of oxygen from the blood, the heart needs 75 percent. So, there is little margin for safety. Interference with clearance mechanism in the respiratory tracts. Chronic bronchitis and emphysema have also been found to be caused by SO2. A twenty-four hour exposure to about 0.2 pm of SO2 may cause serious health problems. Lung cancer has also been found to be correlated with air pollution. Polycyclic aromatic hydrocarbons (PAH) are found to be related to the Pathogenesis of lung cancer. b. Toxicity due to absorbed toxic substance: many toxic particles including metal dusts, asbestos, aromatic hydrocarbons have been discovered in a polluted urban Components of Environment 22

iv.

v.

vi.

vii. viii.

atmosphere. Lead from vehicle exhaust, resulting from the use of tetraethyl lead as an anti-knock additive to petrol, many build up to dangerous level in urban areas adjacent to busy road complexes. Lead in high doses kills outright. In lower doses, it shortens life span and causes deterioration of nervous system. Retarded children have a higher lead content in their body than the normal once. Benzpyrenes: Their concentration is extremely small but they play a role in higher cancer rates in urban areas as compared to rural areas. Peroxyacetyl nitrates (PAN) or photochemical smog may constitute a serious problem where high levels of vehicular emissions occur in cities experiencing bright sunlight and ambient temperature above 21 0C. The small solid particles can severe a carriers for microorganisms and other infective agents and thereby spread disease. Large dust particles are trapped in noise and throat and very tiny particles which stay in the lungs may start any ugly chain of events leading to serious illness and deaths. Air pollution causes coughing, sneezing, thickening of secretion of mucus and narrowing or complete closure of glottis due to presence of gases especially, SO2, nitrogen dioxide and oxidants. The silicon particles may cause “silicosis” and fibrous particles causing “fibrosis”. It is suspected that some pollutants can start the growth of lung cancer. Example of short term effects include irrigation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia. Other symptoms can include headache, nausea and alergic reaction. Similarly the long –term effects can include chronic respiratory diseases, hung cancer, heart diseases and event damages to the brain, nerves liver of kidneys. Carbon oxide causes global warming due to the greenhouse effect. Aerosols like chlorofluro carbons (CFCs) and carbon tetrachloride (CCL4) deplete the ozone layer so that radiation reaches defectively to the earth surfaces. Other particles like pollen grains, soil dust, microbes cause several allergic reactions to human beings. Microbes directly affect the health of all the animals. Effects of the air pollution on plants can be summarized as:  SO2, N2O, O3 and proxy acetyl nitrates (PAN) causes direct damage to leaves of crop plants and trees when they enter leaf pones.  Dust particles deposited on the body of plants decreases photosynthesis.  Productivity of plants decreases  Acid rain causes adverse impacts on highly sensitive plants.

3.4.3 Major Air pollutants Air pollution consists of gases and /or particles. These have a distinct physical or chemical structure, or a distinct effect on human health. The main air contaminants are: 1. Sulphur dioxide (SO2): This contaminant is mainly emitted during the combustion of sulphur – containing fossil fuels, such crude oil and coal. Sulphur dioxide concentrations in air have decreased in the past two decades, mainly because we use more non-sulphur containing fuels for the generation of energy. Sulphur dioxide is a stinging gas and as a result in can cause breathing problems in humans. In moist environment, sulphur dioxide is a stinging gas and as a result it can cause breathing problems in humans. In moist environment, sulphur dioxide may be transformed into sulphuric acid. This acid causes acidification and winter smog. 2.

Nitrogen oxides: These contaminants are emitted by traffic, combustion installations, such as power plants, and the industries. Nitrogen oxides are also released from farmland. Using catalyzers in car exhausts can prevent emissions of nitrogen oxides. Nitrogen oxides are gases that react with other air pollutants when they are present in air. For example, nitrogen oxides play an important role in the formation of ozone in the lower atmosphere, and in acidification


and eutrophication processes. They can deeply penetrate the lungs and damage human lung functions. 3.

Ammonia (NH3): Ammonia forms during agricultural activities. Ammonia plays an important role in acidification and eutrophication.

4.

Volatile Organic Compounds (VOC): VOC can be a range of different organic compounds and solvents. These compounds usually derive from petrol and gasoline reservoirs, industrial processes and fuel combustion, paint and cleanser use or agricultural activities. VOC play and import role in ozone shaping in the lower atmoshpheric layer, the main cause of smog.

5.

Methane (CH4): The main source of methane pollution is agriculture. But smaller amounts of methane are also released during waste combustion and natural gas extraction. Methane s a greenhouse gas that contributes the greenhouse effect and ozone layer loss.

6.

Carbon monoxide (CO): This gas is produced during incomplete combustion of fossil fuels. Carbon monoxide contributes to smog and acidification. The gas can bind to hemoglobin in blood, preventing oxygen transport through the body. This results in oxygen depletion in the heart, brains and blood vessels, eventually causing death.

7.

Dust particles: Dust particles form a complex organic compounds and minerals. They are released from natural sources, such as volcanoes, or human activities, such as industrial combustion process or traffic. Particles are categorized according to particle size. The smallest particles have the ability to transport toxic compounds into the respiratory tract. When they are released into the environment, dust particles can cause acidification and winter smog.

8.

Ozone (O3): Ozone is created through photochemical transfer of oxygen. This process takes place under the influence of ultraviolet light (UV), aided by pollutants in the outside air. Ozone cause smog and contributes to acidification and climate change. Ozone is an aggressive gas, which can easily penetrate th respiratory tract deeply. When humans are exposed to ozone, its consequences may be irritation of the eyes and the infection of the respiratory tract.

9.

Radioactive Radiation: Radioactive radiation and radioactive particle are naturally present in environment. During power plant accidents or treatment of nuclear waste or a war where nuclear weapons are used, radioactive radiation can enter the air. When humans are exposed to high levels of radioactive radiation, the chances of serious health hazards are very high. Radioactive radiation can cause DNA alteration and cancer.

3.4.4 Acid Rain Presence of the more green house gases may cause acid rain. This is the result of industrial pollution or air pollution “Acid Rain” or more correctly acid precipitation is term used to describe polluted rainfall. When the water vapour from the oceans and the land enters the atmosphere it is neutral i.e., pH 7, and is almost pure H2O. In the atmosphere it mixes with the variable amounts of naturally occurring carbon dioxide (CO2) and sulphur (S) and forms weak acids. Depending on the amount of CO2 and S present, the pH of the ensuing rainfall can be in the range 4.5 – 5.6. In the industrialized nations of Europe and North America, heavy combustion of fossil fuels (oil and coal) results in the emission of sulphur dioxide (SO2) and nitrogen oxides (NOX) into the atmosphere. Transformation of these gases into sulphuric acid (H2SO4) and nitric acid (HNO3) leads to further acidification of the water vapour. Acid rain is formed when industrial emissions of gases including sulphur dioxide, nitrogen oxides and hydrogen chloride combine with water droplets in the atmosphere. This chemical reaction forms weak sulphuric and nitric acids that cause acid rain. SO2 + H2O

→H2SO3 + O

→H2SO4 Components of Environment 24

2NO + O2 NH3 + H2O 2NH4OH + H2SO4 NH4OH + HNO3

→2NO2 + H2O + O→2HNO3 →NH4OH → (NH4)2SO4+ 2H2O →NH4NO3 + H2O

Thus, all chemical reactions which result in the formation of fog or smog and reducing type of pollution occur higher up in the atmosphere and give rise to rains of acidic nature which may have a pH in the range of 2.5-4.8. Sulphuric acid, various sulphates and nitrates are the main chemical constituents of these rains, through small amount of other acids like hydrochloric acid and their salts may also be present. This artificial acidification of the cloud water results in an increase in acidity of the precipitation, giving rise to regular occurrence of rainfall episodes with a pH less than 4.0 or even less.

Impacts of Acid Rain 1.

Effect on Soil

Soil are naturally alkaline neutralize acidic deposits. Acidic are more sensitive to acidic deposits. Soils, in general, have a greater buffering capacity than aquatic systems. However, excessive amount of acid introduced by acid rains may disturb the entire soil chemistry. The concentration of sulphates and nitrates rises while more phosphates are released in soluble form. Acidity as well as the harmful action of toxic elements damages vegetation, and the susceptible microbial species are also eliminated. The soil loses its normal functions such as decaying and decomposition of organic debris and the capacity of balance regulation of nutrients. Heavy downpours leach away much of the precious minerals nutrients and desertification follows. 2.

Effect on Plants and Animals

Excessive amount of hydrogen ions adversely affect biological membrane, the electron transport system and a number of pH specific biological reactions. High salts precipitation can alter the soil’s chemistry, which in turn alters the plants growing on it. Changes in communities can then affect the wildlife living on them. Acid rain can damage plants and trees. In higher plants, chlorophyll is degraded and leaves lose their green pigmentation which results in drastic reduction in productivity. A weak tree is more likely to suffer from diseases, insect attacks and cold weather. In aquatic environment, the effect of lowering of pH is usually more pronounced. Small plankton, flagellates, algae, crustacean, and fish like trout and salmon may disappear since they are intolerant to pH below 5. Molluscs also suffer because low pH inhibits the formation of calcareous shell which protects them in addition to the diverse affect caused by disruption of enzymes and electron transport system. In higher animals including human beings, the aerosols and water containing sulphuric acid cause irritation in their eyes. When inhaled, such things may also cause a marked degradation of bronchial constriction which results in significant resistance to the flow of gases in and out of the lungs. This make an individual susceptible to other respiratory ailments. 3.

Effect on Rivers and Lakes Increased levels of acidification of freshwaters were first linked to the decline of slamonid and other fish stokes in Norwegian acid-sensitive Rivers about sixty years ago. Subsequent investigations have shown the many aquatic plants and animals are affected by increased acidity. This has led to major changes in the nature of the flora and fauna of the affected streams and lakes. Originally, it was assumed that such changes were a response to the direct effects of the acidity but it was subsequently shown that an indirect effect of low pH, namely, an increase in the concentration of aluminium, is far more significant. This element, one of the commonest in the earth’s crust, is normally not soluble and is bound to silica at pH 7.0. As the acidity of the water increases, aluminium becomes more soluble from which predominates in the pH range 5.0 to 5.5. However, this Components of Environment 25

toxicity is lessened in the presence of organic compounds such as humic acids and if calcium levels exceed 1.0 mg. The toxic action of acidity is most pronounced in its effect on the fish and micro-invertebrate fauna of streams and lakes. Dissolved aluminium concentration may have non-lethal effects such as respiratory difficulty, impaired growth and reproductive ability which, in the long run, may lead to their elimination. Acid rain can acidify the water bodies it falls into. Acidified water releases aluminium from the soil that the lake covers. The released aluminium can be toxic to plants, fish and insects. In Sweden, acid rain made over 18,000 lakes so acidic that all the fish died. Acid rain has affected some salmon and trout fisheries in small headwater rivers in wales. 4. Corrosive Action Due to the corrosive action of the acid, the acid rain damages wood, steel, buildings, and cement concrete structures. It also damages fabric and other fibrous materials. Many of our monuments which are build up steel, stone, cement or concrete are threatened by the corrosive action of acid rains, for example, the corrosive action of acid rains on TajMahal at agra in India. Despite all these negative impacts, may be few posture impacts of global warming may result in lower heating belts in middle and higher latitudes and longer growing seasons in some areas. Crop yield might also increase because more carbon dioxide in the atmosphere Fig. Tajmahal of Agra affected by the acid rain can increase the rate of photosynthesis. If the concentration of greenhouse gases continues in this very speed, all these effects due to climatic changes by global warming are incontrovertible.

3.5 Noise pollution Noise pollution is excessive, displeasing human, animal, or machine-created environmental noise that disrupts the activity or balance of human or animal life. The word noise may be from the Latin word nauseas, which means disgust or discomfort. The source of most outdoor noise worldwide is mainly construction and transportation systems, including motor vehicle noise, aircraft noise, and rail noise. Poor urban planning may give rise to noise pollution, since side-by-side industrial and residential buildings can result in noise pollution in the residential area. High noise levels can contribute to cardiovascular effects in humans, a rise in blood pressure, and an increase in stress and vasoconstriction, and an increased incidence of coronary artery disease. In animals, noise can increase the risk of death by altering predator or prey detection and avoidance, interfere with reproduction and navigation, and contribute to permanent hearing loss.

3.5.1 Causes of Noise Pollution Sound pollution is unwanted, untimely and unpleasant sound. It is the exposure of the people or animals to the levels of sound that are annoying, stressful, damaging to the ears. Some sources of sound pollution are: 1.

Industries A mechanized industry creates serious noise problems. It is responsible for high noise emissions indoors as well as outdoor of its plants. This noise is due to machinery of all kinds which often increase with the power of machines. The characteristics of industrial noise vary considerably, depending on specific equipment. In industrial areas, the noise usually stems from a wide variety of sources, many of which are of complex nature. Machinery should preferably be silenced at the source. Components of Environment 26

Noise from fixed installations such as factories or construction sites, heating pumps and ventilation system plants on roof, can also affect the nearby communities. 2.

Residential Areas In residential areas, noise may stem from mechanical devices (e.g. heat pumps and ventilation systems, traffic) as well as voices, music and other kinds of noise generated by neighbors (e.g. lawn mowers, vivid parties, and other social activities). 3.

Transportation Noise (a) Road traffic The noise of road vehicles is mainly generated from the engine and from frictional contact between the vehicles, the ground and air. The amount of noise generated by road traffic depends on the speed of the vehicles, degree of loading, traffic density, condition of the vehicles and condition of the road. Fig : Vehicles in Kathmandu valley using fuel

(b) Rail traffic Railway noise depends primarily on the speed of the train but it varies depending on the type of engine, wagons and rails. The introduction of highspeed trains has created special noise problems. At speed greater than 250 km / h, the proportion of high frequency sound energy increases and the sound can be perceived as similar to over flying jet aircraft. Fig: Railway service of Nepal

(c)

Air traffic Aircraft take offs are known to produce intense noise including vibration and rattle but landings also cause noise annoyance in general. Larger and heavier aircrafts produce more noise than lighter aircrafts.

Fig: Flying aeroplane

4. Construction noise, Public Workers Noise and Military Noise Building construction and earth works are activities that can cause considerable noise emission. A verity of sounds is produced from cranes, cement mixers, welding, hammering, boring, and other work processes. Construction equipment is often poorly silenced and maintained, and building operations are sometimes carried out without considering the environmental noise consequence. Street services such as garbage disposal and street cleaning can cause considerable disturbance if carried out at sensitive times of the day. In certain instances, military activities may be an important noise source such as noise produced by heavy vehicles (tanks), helicopters, and small and large firearms.


5. Domestic Noise Noise from neighborhood is often one of the main causes of noise complaints. These complaints are largely due to the inconsiderate or thoughtless use of powered domestic appliances (vacuum cleaners, washing machines, lawn mowers, etc.) music system, TV sets or hobby related activities. Substantial societal problems, more infrequent but nonetheless important, are caused by disturbing noise emanating from neighbors and their social activities. 6. Noise from Leisure Activities The possibilities of using powered machines in leisure activities are increasing all the time. For example, car racing, off-road vehicles, motorboats, water skiing, snowmobiles, etc., can all contributes significantly to loud sound pressure levels in previously quite areas. Shooting activities not only have considerable potential for disturbing nearby residents, but can also damage the hearing of those taking part. The general problem of access to leisure activity sites often adds to the road traffic noise problems in particular areas.

3.5.2 Effects of noise pollution The effect of the noise pollution is not direct most of the time. It is related mostly related to the mental health. A. The different effects on human beings are categorized as auditory and non-auditory effects. 1.

Auditory Effects These include auditory fatigue, and deafness. Auditory fatigue appears in the 90 dB and may be associated with side effects as whistling and buzzing in ears. Deafness can be caused due to continuous noise exposure. Temporary deafness occurs at 4000-6000 Hz. Permanent loss of hearing occurs at 100 dB. 2.

Non-auditory Effects a. Interference with speech communication: a noise of 50-60 dB commonly interferes with speech. b. Annoyance: balanced persons express great annoyance at even low levels of noise as crowd, highway, radio, etc. The effects are ill temper, bracketing, etc. c. Loss in working efficiency: There develops tiredness and in doing mental work and it may put to deterioration in their efficiency or even complete loss of ability to work. d. Physiological disorders: There develops a number of physiological disorders due to imbalance in functioning of the body. These are neurosis, anxiety, insomnia, hypertension, hepatic disease, behavioral and emotional stress, increase in sweating, giddiness, nausea, fatigue, etc. Noise also cause visual disturbance and reduces depth and quality of sleep thus affecting overall mental and physical health. Other effects are undesirable changes in respiration, circulation of blood in skin and gastrointestinal activity. Noise pollution also cause incidence of peptic ulcers.

Continuous noise causes increase in cholesterol level resulting in the constriction of blood vessels making you prone to heart attack and strokes. There may be still birth and usually low weight children born, to mothers living near airports. Some of the important health hazards of noise are as follows: S.N 1. 2. 3. 4. 5.

Noise intensity (dB) 80 90 95 110 120

Health hazards Annoyance Hearing damage Very annoying Stimulation of reception in skin Pain threshold Components of Environment 28

6. 7. 8. 9. 10. B.

130-135 140 150 160 180

Nausea, vomiting, dizziness Pain in skin Burning of skin Rupture of tympanic membranes Major permanent damage in short time.

Effects on plants and property

We know that plants are similar to human beings. There should be cool and peaceful environment for better growth. So, Noise pollution causes poor quality of crops than in pleasant atmosphere. Loud noise is very dangerous to buildings, bridges and monuments. It creates waves which strike the walls and put the building in dangerous condition after a long time. It weakens the edifice of buildings. 3.5.3 Controlling measure of sound pollution a) b) c) d) e) f) g) h) i) j) k)

Modifying noisy activities and devices to produce less noise. Shielding noisy devices or processes. Moving noisy operations or things away from people Establishing airport, rail station, bus station, industries far away from residential areas. Using anti-noise, a new technology that cancels out one noise with another. Planting trees along the both sides of the road, around industrial areas. Using acoustic material in cinema halls. Controlling traffic jam. Improving road condition. Making people awareness on effect of noise. Managing legal provision.

3.6 Industrial Pollution Introduction Industrial pollution is pollution which can be directly linked with industry, in contrast to other pollution sources. This form of pollution is one of the leading causes of pollution worldwide; in the United States, for example, the Environmental Protective Agency estimates that up to 50% of the nation's pollution is caused by industry. Because of its size and scope, industrial pollution is a serious problem for the entire planet, especially in nations which are rapidly industrializing, like China. There are a number of forms of industrial pollution. One of the most common is water pollution, caused by dumping of industrial waste into waterways, or improper containment of waste, which causes leakage into groundwater and waterways. Industrial pollution can also impact air quality, and it can enter the soil, causing widespread environmental problems. There are about seventeen varieties of industries which are declared to be the most polluting. These include the caustic soda, cement, distillery, dyes and dye intermediaries, fertilizers, iron and steel, oil refineries, pulp and paper pesticides and pharmaceuticals, sugar, textiles, thermal power plants and tanneries. The wide varieties of pollutants as shown above enter the environment and disturb the natural ecosystem affecting the biota. Due to industrial activities, a variety of poisonous gases like NO, SO 2, NO2, SO3, Cl2, CO, CO2, H2SO4, as well as volatile chemicals and dust etc. are librated into the atmosphere causing acute pollution problems. Besides, the accidental leakage of poisonous gases can cause havoc. For example, methyl isocyanate gas leakage from Union Carbide factory at Bhopal (India) caused mass killing which is still known as Bhopal gas tragedy. In addition to accidents, many of the above poisonous gases induce depletion of ozone layer, creating of ozone hole, green house effect, global warming, acid rain, destruction of monuments and killing of living organisms disturbing the natural ecosystems. Components of Environment 29

3.6.1 How do Industries Affect the Environment? The first and the most obvious ways in which industries affect the environment is the pollution caused by factories. The most visible are the water, solid-waste and air pollution that can be felt and seen. The nature and composition of industrial waste and pollutants vary widely from one industry to another industry and even within the same industry. The waste generated depends on the raw materials, processes, and operating factories. Different industries generate different types of pollutants. For example, food processing industries produce organic wastes that are readily decomposed but have high biological oxygen demand (BOD); pulp and paper mills produce toxic compounds and sludge; the electronic industry produces high level of heavy metals such as copper, lead, manganese, etc. Apart from the pollution that they produce, industries affect the environment in other ways, too. Some of the components and effects are discussed as: 1.

Raw materials The most basic need of any industry, be it the paper industry, the textile industry or the cement industry, is raw materials. A factory can turn out anything i.e. aeroplanes or cloth or paper. But it needs raw materials; for instance, aluminium to make an aeroplane, natural or synthetic fibres to make cloth, wood/grass pulp to turn into paper. The extraction and mining of raw materials, and the processing of the raw materials, e.g., ores into metal, having major environmental impacts. For instance, if limestone is to be mined for cement production, large areas of land may have to be made productive with chemical fertilizers, and heavily sprayed with chemical pesticides, insecticides, herbicides to get a good crop. If wood is to be fed to a paper factory, hectares of trees or bamboo will have to be cut down. 2.

Transport of raw materials Getting the raw materials from the site or field from where it is extracted and other inputs to the factory, involves transportation. This takes its own role on the environment in terms of the fossil fuels consumed and various other types of pollution caused by the transport. 3.

Other inputs In addition to the raw materials, most production needs water and power. They may draw water either from surface water sources (e.g., rivers, lakes, etc.), or they may tap groundwater. In either case, there are serious environmental impacts to be considered, especially if the operation is large scale or water-intensive. For example, if a factory comes up in a semi-arid area where ground-water levels are already low, it may draw so much water that the availability of drinking water for the local communities might reduce. After all, it is the same limited ground water that both would be trying to draw out. The other essential input for any production process is power. Power, whether generated in a hydro plant, thermal plant, nuclear plant, or by other means, has serious impacts on the environment. So, every kilowatt of power that the factory draws has environmental impacts. Increased industrial activity since the Industrial Revolution is one of the main causes of air pollution. With growing populations and industries, the need for energy has increased manifold. To meet this increased power requirement, mega-power projects have come up. The use of coal in thermal power stations has lead to the increase in air pollutants such as various oxides of carbon, sulphur and nitrogen. Apart from these, thermal power stations produce large quantities of fly ash as a by- product, which covers large areas of land with fluffy, sooty layer. The great leaps in industrial production have been achieved by mushrooming of industrial establishments such as steel and chemical plants, paper plants, refineries, petro-chemical plants, power plants, and more. With this has come an increase in the pollutants discharged by industries. The emissions from these contain not only smoke and soot, but also other particulate as well as gaseous pollutants. These pollutants can have serious consequences not only human health, but also on flora and fauna, soil, water and human-made structures. Components of Environment 30

4.

Production processes Of course, the production process itself has impacts on the environment. It may generate pollutants and waste materials in the form of liquids, solids, gases or even noise or heat. Some of this may be toxic or hazardous and long lasting. Some of it may pollute the immediate environment; some may travel hundreds of miles into another state or country. Industries also often contribute to noise pollution through the production process, e.g., from the running of motors. This is also a form of pollution. 5.

Packaging After the production process, the production has to be package and transported. This again impacts the environment. Packaging is getting more and more resource intensive, e.g., biscuits are packed in a whirl of corrugated paper and then in a plastic sheet, which may then put into a carton. Each of these packing materials has gone through their own processing cycles. After packing, the ready product has to be transported to the various, far-flung markets. Transportation also uses up resources and creates pollution. 6.

Environmental impact of use When a product is used, it affects the environment. For instance, when we buy a scooter, we will need a large amount of fossil fuel to run it. Similarly, a washing machine will need water, detergent and electricity to run it. This process will continue throughout the life of product. Thus, a manufacturing industry takes raw materials, processes it, and puts out both the product, and the by-products, which are a necessary but undesired outcome of the production process. In industries, many types of raw materials, chemicals, fuel, etc. are used. The consumption of these contributes to pollution. Pollution affects the physical, chemical, and biological environment.

3.6.2 Effects of the industrial pollution Pollution given off by various industries and factories are often considered to be one of the prime factors contributing to air, water and soil pollution. There are various wide ranging effects as well as serious consequences of industrial pollution on the ecological balance of the atmosphere. According to the Environmental Protection Agency, it has been estimated that industrial pollution is responsible for almost 50 percent of the pollution present in the united state. There are various wideranging effects, as well as serious consequences, of industrial pollution on the ecological balance of the atmosphere. a)

Global Warming and Climate Change Global warming is one of the most common and serious consequences of industrial pollution. The emission of various greenhouse gases such as CO2, methane increases the overall temperature of the earth, resulting in global warming. Global warming has various serious hazards, both on the environment as well as on human health. It results in melting of glaciers and snow-capped mountains, causing of flood. Apart from this, global warming also has numerous health risks on humans, such as increase of diseases like malaria and dengue, cholera etc. b)

Air pollution Coal, diesel, petrol, etc., are used as fuel in most of the industries. Industries produce smoky mixture of carbon monoxide and organic compounds due to incomplete burning of fossil fuels like coal, petrol and diesel. The factories of cement, marble, stones, and bricks produce much more dust particles, which are released into the atmosphere. In the same way, ghee and oil treatment industries produce pollutants like sulphur dioxide, nitrogen oxide, hydrocarbons, carbon monoxide, and ammonia gases. Coal, diesel, kerosene, husk (Bhoos) are used as principal source of heat energy in garment and dying industries. In the combustion of husk, a large amount of dust particles are produced. The waste water produced by soap industry, leather industry, sandal industry, nylon industry, plastic industry, Components of Environment 31

cotton industry, etc. give out quite unpleasant odour to the surroundings. In this way, different gases as well as dust particles released by industries are air pollutants which affect the environmental condition. c)

Water pollution Contamination of streams, lakes, underground water, bays or oceans by substances harmful to living beings is called water pollution. Leather industry, carpet industry, dyeing industry, and others use huge amount of water and they also produce waste water. Such waste water contains lead, cadmium, chromium, benzene, mercury, polychlorinated biphenyl, heavy metals, etc. These chemicals pollute the water resources and the organisms living there are also affected adversely. For example, the waste water from Bhrikuti paper Mill situated in Nawalparasi district is directly released in the Narayani River is decreasing. Water is necessary for life on earth. All organisms contain it, some drink it. Plants and animals require water that is moderately pure and they cannot survive if their water is loaded with toxic chemicals or harmful microorganisms. Severe water pollution can kill a large number of fish, birds and other animals, in some cases killing all members of a species in an affected area. Pollution makes streams, lakes and coastal water unpleasant to look at, to smell and to swim in. fish and shellfish harvested from polluted waters may be unsafe to eat. People who ingest polluted water can become ill and with prolonged exposure, may develop cancers or bear children with birth defects. d)

Land pollution Leather industry, cell-battery, paper industry, dyeing industry, etc., throw their wastes first on the land. The non-degradable materials such as broken glasses, plastics, damaged electrical goods, etc, cause land pollution. The dust particles produced by cement industry, stone industry, brick industry, etc., also pollute land. The collection of biodegradable solid wastes also pollute land. The wastes produced by industries are carried by rainwater and they get mixed with the surface water. Such wastes after mixing with soil also destroy the properties of soil. e)

Sound pollution Unwanted sound is considered as a form of pollution. Noise pollution is at its worst in densely populated areas. The operating industries produce noise in their surroundings. The level of sound, which is difficult to bear with, is known as sound pollution. In industries like cement industry, concrete industry, metal works industry, etc. there are huge machines which produce much noise. These industries, sometimes, produce sound of more than 110 decibel. f)

Solid waste The wastes produced by industries are of two forms, which are solid and liquid. Small pieces of metals and poisonous chemicals are produced by metal industries. Dust particles are produced by cement industries and tobacco dusts and other wastes are produced by cigarette industries. Sometimes, the chemical wastes react with each other and they may produce fire that may also get mixed with water, thus polluting the water resources. g)

Effects on the health of living beings Noise, dust particles, solid wastes, smoke, etc., produced by industries directly affect human health. Noise pollution can cause loss of hearing stress, high blood pressure, loss of sleep, distraction, and lessening of workers’ productivity. The storage, transportation, use and disposal of these substances pose serious environmental and health risks. Even brief exposure to some of these materials can cause cancer, birth defects, nervous systems disorders, and even death. The use of contaminated water may cause skin allergy. The contaminated water may change the habitat of the wildlife. It directly affects the aquatic life. h)

Acid rain “Acid Rain” or more correctly acid precipitation is term used to describe polluted rainfall. This is the direct consequence of industrial pollution. When the water vapour from the oceans and the land enters the atmosphere it is neutral i.e., pH 7, and is almost pure H2O. In the atmosphere it mixes with Components of Environment 32

the variable amounts of naturally occurring carbon dioxide (CO 2) and sulphur (S) and forms weak acids. Depending on the amount of CO2 and S present, the pH of the ensuing rainfall can be in the range 4.5 – 5.6. In the industrialized nations of Europe and North America, heavy combustion of fossil fuels (oil and coal) results in the emission of sulphur dioxide (SO 2) and nitrogen oxides (NOX) into the atmosphere. Transformation of these gases into sulphuric acid (H2SO4) and nitric acid (HNO3) leads to further acidification of the water vapour. During rainfall this acidic water comes to the earth surface which is termed as acid rain.

3.6.3 Controlling measures can be summarized in the following headings a.

Measures to Control Location of Industries

The main object of an industrialist for locating his industry at a particular place is his profit. The town planning authorities should be concerned in location of an industry from the view point of the public interest. The success of measures adopted to control location of industries will depend on the adjustment of these two motives or interests. Following are the three important ways which are adopted for controlling the location of industries; ,

1.

2.

Fig: Emission from the industries By Developing Industrial Townships The favorable sites for industries are set apart and they are then developed as industrial centers or townships. Such townships may be equipped with facilities which attract various industries to settle in them. The requirements of workers as well as economic, social and political needs of the community are accommodated in the design of industrial townships. By Granting Concessions The establishment of industries at certain places in the country may be encouraged by granting concessions in various forms such as giving land at nominal lease rent, extending loans with attractive terms, supplying water and power at concessional rates, reducing railway freight charges, imposing nominal local taxes, etc.

3.

By Imposing Restrictions The development of certain industries is prohibited in particular area by law. If similar industries already exist in that area, a time limit is fixed for vacating or stopping the use of premises to run such industries.

b.

Control and Treatment Methods of the Wastes

Treatment methods for industrial wastes will depend upon their characteristics and various other factors. In general, treatment recommended should be such that it recovers some useful substances from the industrial wastes. This will encourages the industry owner for the suitable treatment to the industrial wastes and it will also reduce the cost of such treatment . Following are the methods adopted for the treatment of industrial wastes i) Aerobic biological oxidation; ii) anaerobic digestion; iii) Chemical coagulation; iv) chemical oxidation; v) Chlorination; vi) deionization; vii) Dewatering and drying; viii) filtration; ix) Incineration; x) lagooning or ponding; xi) Screening; xii) sedimentation; xiii) spray irrigation xiv) vacuum filtration, etc. Components of Environment 33

1.

2.

Control and treatment of solid wastes Solid waste create by industry are collected and managed by appropriate methods. Methods for managing waste material depend on its type. The following are some procedures of solid waste materials management. a) The waste water produced from beverage manufacture industry, leather industry and carpet dyeing industry should be managed by treating it in a waste water treatment plant. b) The pieces of leather may be reused in preparing different types of goods. Later than all, the waste should be disposed in appropriate places. The solid wastes should be reused as far as possible. c) Biodegradable materials should be collected in a dumping spot so that compost fertilizers could be prepared from them. It is also necessary to make people conscious of solid waste management. Control and treatment of waste water It is seen that the majority of the industrial effluents increase either directly or through a canal. Hence, the introduction of an effluent into any natural stream is only through laminar sub-layer, where the flow is nearly longitudinal, which does not allow any axial mixing. This is the only reason why a huge number of fish are found dead with the input of intense quantity of effluent whether it is organic or inorganic. An appropriate arrangement of disposal of effluents could be made away from the riverbank in order to check the possibility of killing of living beings. Even those animals that give milk to us also drink water from greatly polluted laminar zone. Hence, there should be proper disposal of industrial effluents at suitable points in the getting stream so that it can go a long way to completely utilize the absorption capacity.

3.

Control of smoke The smoke created by different industries should be controlled according to the rule in opposition to environment pollution. Plantation of green plants around industrial region absorbs the smoke from the atmosphere. Use of alternative energy should be encouraged instead of using fossil fuel energy continuously.

4.

Control of dust particles There must be plantation of green plants along the roadside which helps to absorb the dust particles evolved due to movement of means of transportation. This helps to decrease the distribution of dust in the atmosphere. Again dust particles are greatly produced from the crusher, cement industry, marble factory, etc. so there should be provision of installing dust absorbers in these industries.

5.

Control of sound pollution Some of the procedures for controlling sound pollution are as follows:  There should be timely servicing of the machinery used in industries. Proper use of lubricants in machines decreases sound pollution.  The wall of the building containing noise-producing machines should be prepared sound proof in order to decrease sound pollution.  Plantation should be done around the industrial area.

EXERCISE A)

Very short questions: 1) 2) 3) 4) 5) 6)

Defined population. Give any tow examples of environmental population? What are pollutants? Give example. State example of Hazardous waste. Define eutrophication. What as thermal pollution?


7) 8) 9) 10) 11) 12) 13)

B.

Short answer type questions: 1) 2) 3) 4) 5) 6) 7) 8) 9)

C.

Define pollution. State different types of environmental pollution and explain any one of them. What is air pollution? State any three causes of air pollution. State different organic and inorganic pollutants of water pollution. Describe briefly the agriculture based pollution. State different ways of water purification and explain any one of them. Describe SODIS method of water purification. What does the air quality standard mean? Explain. What is acid rain? Describe briefly. What is industrial pollution? Industrial pollution is the cause of all other environmental pollution justify.

Long answer questions: 1) 2) 3) 4) 5) 6) 7) 8)

D.

State3 any two methods of water pollution? Write Full form of? DDT,SODIS,CFC,BOD,COD,VOC,PCB,BHC,PAN Which gas is found in the greatest volume in atmosphere and by what percentage? What Magnitude of sound can be heard by human beings? What magnitude of sound causes sound pollution? State any two major air pollutants? What is the range of PH of acid rain?

What is environmental pollution? Introduce different types of environmental pollution in brief. What is water pollution? Explain its sources, effects and preventive measures in brief. What is air pollution? Explain its sources, effects and preventive measures in brief. State any 12 air pollutants with their effects. What is water purification? Explain different methods of water purification in brief. What is noise pollution? Explain its sources, effects and preventive measures in brief. What is industrial pollution? Explain how industries affect environment. Also state ways to minimize this pollution. What is acid rain? Explain. Also describe different impacts of acid rain in brief.

Practical problems: 1) 2) 3) 4)

Visit a nearby polluted river of pond or any water resources and make a report on it. Visit a nearby air polluted area and make report on it. Visit any industry or factory around you and write a report on pollution through it. Write a report on conservation of water resource around you. The report must contents: - Introduction to the location of study. - Objectives. - Observation of the subject matter i.e. sources. - Causes of the subject matter (pollution). - Conclusion and recommendation.

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UNIT Change in climate 4.1 Introduction Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions, or in the distribution of weather around the average conditions (i.e., more or fewer extreme weather events). Climate change is caused by factors that include oceanic processes (such as oceanic circulation), variations in solar radiation received by Earth, plate tectonics and volcanic eruptions, and human-induced alterations of the natural world; these latter effects are currently causing global warming, and "climate change" is often used to describe human-specific impacts. Scientists actively work to understand past and future climate by using observations and theoretical models. Borehole temperature profiles, ice cores, floral and faunal records, glacial and periglacial processes, stable isotope and other sediment analyses, and sea level records serve to provide a climate record that spans the geologic past. More recent data are provided by the instrumental record. Physically based general circulation models are often used in theoretical approaches to match past climate data, make future projections, and link causes and effects in climate change.

4.1.1 Causes of the climate change Major causes of the climate change can be discussed under two groups they are: Natural Causes of Climate Change The earth’s climate is influenced and changed through natural causes like volcanic eruptions, ocean current, the earth’s orbital changes and solar variations. Volcanic eruptions - When a volcano erupts it throws out large volumes of sulphur dioxide (SO 2), water vapour, dust, and ash into the atmosphere. Large volumes of gases and ash can influence climatic patterns for years by increasing planetary reflectivity causing atmospheric cooling. Tiny particles called aerosols are produced by volcanoes. Because they reflect solar energy back into space they have a cooling effect on the world. The greenhouse gas, carbon dioxide is also produced however the CO2 produced is insignificant when compared to emissions created by humans. Ocean current - The oceans are a major component of the climate system. Ocean currents move vast amounts of heat across the planet. Winds push horizontally against the sea surface and drive ocean current patterns. Interactions between the ocean and atmosphere can also produce phenomena such as El Niño which occur every 2 to 6 years. Deep ocean circulation of cold water from the poles towards the equator and movement of warm water from the equator back towards the poles makes the poles colder and the equator warmer. The oceans play an important role in determining the atmospheric concentration of CO2. Changes in ocean circulation may affect the climate through the movement of CO2 into or out of the atmosphere. Components of Environment 37

Earth orbital changes - The earth makes one full orbit around the sun each year. It is tilted at an angle of 23.5° to the perpendicular plane of its orbital path. Changes in the tilt of the earth can lead to small but climatically important changes in the strength of the seasons, more tilt means warmer summers and colder winters; less tilt means cooler summers and milder winters. Slow changes in the Earth’s orbit lead to small but climatically important changes in the strength of the seasons over tens or thousands of years. Climate feedbacks amplify these small changes, thereby producing ice ages. Solar variations - The Sun is the source of energy for the Earth’s climate system. Although the Sun’s energy output appears constant from an everyday point of view, small changes over an extended period of time can lead to climate changes. Some scientists suspect that a portion of the warming in the first half of the 20th century was due to an increase in the output of solar energy. As the sun is the fundamental source of energy that is instrumental in our climate system it would be reasonable to assume that changes in the sun's energy output would cause the climate to change. Scientific studies demonstrate that solar variations have performed a role in past climate changes. Current global warming however cannot be explained by solar variations. Some examples are evidenced such as since 1750, the average amount of energy coming from the Sun either remained constant or increased slightly. If global warming was caused by a more active sun, then scientists would expect to see warmer temperatures in all layers of the atmosphere. They have only observed a cooling in the upper atmosphere, a warming at the surface and in the lower parts of the atmosphere. This is due to greenhouse gasses capturing heat in the lower atmosphere. Also climate models that include solar irradiance changes cannot reproduce last century's observed temperature trend without including a rise in greenhouse gases.

Human influences Human activities that causes climate change includes 1)

Green house effect

The greenhouse effect is an environmental problem. Greenhouse a term used to describe a range of gases, which trap radiation emitted from the earth's surface, and hence keep the planet warmer than it would otherwise be. Carbon dioxide, methane, nitrous oxides and ozone are all greenhouse gases; the order of importance in contributing to human induced global warming is carbon dioxide (10%), methane (20%) and others (10%). 2)

Deforestation

Humans escalate the amount of carbon dioxide released into the atmosphere when they burn fossil fuels, solid wastes, and wood including wood products' to heat buildings, drive vehicles, generate electricity, and for various other purposes. At the same time, the number of trees that absorb carbon dioxide for photosynthesis has been greatly reduced by deforestation. Forests have been destroyed for obtaining timber as well as preparing land for agriculture. Due to deforestation there is decrease in water retaining capacity of the land and the rate of evaporation as well. This ultimately affects the natural condition of the climate. 3)

Visibility of Atmosphere

Urban air pollution is commonly known as smog. Brown Smog over Phoenix and the Arizona Smog are caused by industrial and automobile pollution. The contamination of the earth's atmosphere caused by human beings can take many forms and has existed since humans first began to use fire for agriculture, heating, and cooking purposes. The dark smog is generally a smoky mixture of carbon Components of Environment 38

monoxide and organic compounds formed by the incomplete combustion (burning) of fossil fuels such as coal, and sulphur dioxide formed from the impurities in the fuels. As the smog ages and reacts with oxygen, organic and sulphuric acids, it condenses in the form of droplets, which increases the haze. This disturbs the visibility of atmosphere as well as evaporation rate, which leads to change in temperature of the atmosphere. This subsequently helps in changing the climate of the earth.

4.2 Global warming 4.2.1 Introduction Global warming is the rise in the average temperature of Earth's atmosphere and oceans. Since the early 20th century, Earth's mean surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980.Warming of the climate system is unequivocal, and scientists are more than 90% certain that it is primarily caused by increasing concentrations of greenhouse gases produced by human activities such as the burning of fossil fuels and deforestation. These findings are recognized by the national science academies of all major industrialized nations. Warming and related changes will vary from region to region around the globe. The effects of an increase in global temperature include a rise in sea levels and a change in the amount and pattern of precipitation, as well a probable expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with the continuing retreat of glaciers, permafrost and sea ice. Other likely effects of the warming include a more frequent occurrence of extreme-weather events including heat waves, droughts and heavy rainfall, ocean acidification and species extinctions due to shifting temperature regimes. Effects significant to humans include the threat to food security from decreasing crop yields, the loss of habitat from inundation. If global mean temperature increases to 4 °C (7.2 °F) above preindustrial levels, the limits for human adaptation are likely to be exceeded in many parts of the world and natural systems throughout the world would be largely unable to adapt, resulting in the loss of the benefits (ecosystem services) that those systems provide and upon which human livelihoods depend.

4.2.2 Causes of the global warming Global warming is a result of increasing temperature of earth's atmosphere due to several factors that can be natural or man-made. Whatever may be the factors the effect of global warming is not in favor of mankind and hence need to be controlled. Causes of the global warming can be discussed as: Greenhouse gases The greenhouse effect is the process by which absorption and emission of infrared radiation by gases in the atmosphere warm a planet's lower atmosphere and surface. Naturally occurring amounts of greenhouse gases have a mean warming effect of about 33 °C (59 °F). The major greenhouse gases are water vapor, which causes about 36–70% of the greenhouse effect; carbon dioxide (CO2), which causes 9–26%; methane (CH4), which causes 4–9%; and ozone (O3), which causes 3–7%. Clouds also affect the radiation balance through cloud forcing similar to greenhouse gases. Human activity since the Industrial Revolution has increased the amount of greenhouse gases in the atmosphere, leading to increased radiative forcing from CO 2, methane, tropospheric ozone, CFCs and nitrous oxide. The concentrations of CO2 and methane have increased greatly since 1950. These levels are much higher than at any time during the last 800,000 years, the period for which reliable data has been extracted from ice cores. Less direct geological evidence indicates that CO2 values higher than this were last seen about 20 million years ago. Fossil fuel burning has produced about Components of Environment 39

three-quarters of the increase in CO2 from human activity over the past 20 years. The rest of this increase is caused mostly by changes in land-use, particularly deforestation. Over the last three decades of the 20th century, gross domestic product per capita and population growth were the main drivers of increases in greenhouse gas emissions. CO 2 emissions are continuing to rise due to the burning of fossil fuels and land-use change. Emissions can be attributed to different regions. Particulates and soot Global dimming, a gradual reduction in the amount of global direct irradiance at the Earth's surface, was observed from 1961 until at least 1990. The main cause of this dimming is particulates produced by volcanoes and human made pollutants, which exerts a cooling effect by increasing the reflection of incoming sunlight. The effects of the products of fossil fuel combustion (CO 2 and aerosols) have largely offset one another in recent decades, so that net warming has been due to the increase in non CO2 greenhouse gases such as methane. Radiative forcing due to particulates is temporally limited due to wet deposition which causes them to have an atmospheric lifetime of one week. Carbon dioxide has a lifetime of a century or more, and as such, changes in particulate concentrations will only delay climate changes due to carbon dioxide. In addition to their direct effect by scattering and absorbing solar radiation, particulates have indirect effects on the radiation budget. Sulphates act as cloud condensation nuclei and thus lead to clouds that have more and smaller cloud droplets. These clouds reflect solar radiation more efficiently than clouds with fewer and larger droplets, known as the Twomey effect. This effect also causes droplets to be of more uniform size, which reduces growth of raindrops and makes the cloud more reflective to incoming sunlight, known as the Albrecht effect. Indirect effects are most noticeable in marine strati form clouds, and have very little radiative effect on convective clouds. Indirect effects of particulates represent the largest uncertainty in radiative forcing. Soot may cool or warm the surface, depending on whether it is airborne or deposited. Atmospheric soot directly absorbs solar radiation, which heats the atmosphere and cools the surface. In isolated areas with high soot production, such as rural India, as much as 50% of surface warming due to greenhouse gases may be masked by atmospheric brown clouds. When deposited, especially on glaciers or on ice in arctic regions, the lower surface albedo can also directly heat the surface. The influences of particulates, including black carbon, are most pronounced in the tropics and sub-tropics, particularly in Asia, while the effects of greenhouse gases are dominant in the extra tropics and southern hemisphere. Solar activity Solar variations causing changes in solar radiation energy reaching the Earth have been the cause of past climate changes and global warming. The effect of changes in solar forcing in recent decades is uncertain, but small, with some studies showing a slight cooling effect, while others studies suggest a slight warming effect. Greenhouse gases and solar forcing affect temperatures in different ways. While both increased solar activity and increased greenhouse gases are expected to warm the troposphere, an increase in solar activity should warm the stratosphere while an increase in greenhouse gases should cool the stratosphere. Radiosonde (weather balloon) data show the stratosphere has cooled over the period since observations began (1958), though there is greater uncertainty in the early radiosonde record. Satellite observations, which have been available since 1979, also show cooling. Feedback Feedback is a process in which changing one quantity changes a second quantity, and the change in the second quantity in turn changes the first. Positive feedback increases the change in the


first quantity while negative feedback reduces it. Feedback is important in the study of global warming because it may amplify or diminish the effect of a particular process. The main positive feedback in the climate system is the water vapor feedback. The main negative feedback is radiative cooling through the Stefan–Boltzmann law, which increases as the fourth power of temperature. Positive and negative feedbacks are not imposed as assumptions in the models, but are instead emergent properties that result from the interactions of basic dynamical and thermodynamic processes. Causes can be summarized as:  The main reason behind global warming is the increase in the concentration of greenhouse gases in the atmosphere due to greenhouse effect. Greenhouse effect leads to increase in the temperature of earth by trapping the sun's heat and light in the earth's atmosphere. In this phenomenon the heat and light of sun enters the atmosphere but cannot go out as they are trapped in earth's atmosphere by the greenhouse gases and thus resulting in temperature rise. The greenhouse gases like carbon dioxide, methane, and nitrous oxide plays the major role in greenhouse effect and excessive emission of these gases through various means is a major cause of global warming.  Another important reason for global warming is large amounts of carbon dioxide produced from burning of fossil fuels for the different purposes especially for power generation in various power plants. Due to burning of large amount of coal in power plant excessive amount of carbon dioxide is emitted in different forms in the atmosphere. In addition to that, countless number of vehicles running in the road today is one of the major sources of emission of a large amount of carbon dioxide in the atmosphere leading to increase in the temperature of earth's atmosphere.  Methane is another greenhouse gas that results in global warming to a large extent. Methane can be easily obtained from rice paddies, bovine flatulence, bacteria in bogs and fossil fuel manufacture and hence easily available in abundance. Moreover, it is 20 times as effective as Carbon dioxide at entrapping heat in the atmosphere and is a leading cause of global warming. Similarly, another greenhouse gas called nitrous oxide and chlorofluorocarbons or CFCs is also responsible for the global warming. Nitrous oxide has 300 times more capacity of trapping heat than carbon dioxide while chlorofluorocarbons have heat-trapping potential thousands of times greater than carbon dioxide.  Another major cause of global warming is continuous cutting of a large number of trees across the world that is also referred as deforestation. It is projected that, 34 million acres of trees are cut and burned each year resulting in 25% of all carbon dioxide release entering the atmosphere.  Increasing population is another cause of global warming that cannot be neglected. As human being is known to exhale carbon dioxide means more population will lead to more emission of carbon dioxide in the atmosphere resulting in increase in the level of carbon dioxide in the atmosphere and thus resulting in global warming.

4.2.3 Effects of the global warming This has been the warmest decade since 1880. In 2010, global surface temperatures tied 2005 as the warmest on record, according to the National Oceanic and Atmospheric Administration. Scientists say that the earth could warm by an additional 7.2 degrees Fahrenheit during the 21st century if we fail to reduce emissions from burning fossil fuels, such as coal and oil. This rise in average temperature will have far-reaching effects on the earth's climate patterns and on all living things. Major effect of Global warming are: a)

Ecosystem will be affected adversely because they cannot keep in place with the shifting climate pattern. Components of Environment 41

b) c) d) e) f) g) h) i) j) k) l) m) n) o) p)

The thermal expansion of oceans will submerge many valuable fertile low coastal regions. Coastal islands are under danger. The melting of ice sheet and sliding into the adjacent ocean will cause the sea level rise. The raise in the sea surface temperature will influence the circulation pattern of the ocean current. It causes change in the wind circulation current. Evaporation and transpiration will change from region to region. There will be water shortage in cities. Soil moisture in winter will decrease. Droughts and forest fires will be common. Bleaching of coral reefs occurs. Causes climate change. Causes Acid rain. Northward migration of some warm climate fish and trees. Shift in regional climate would threaten many parks, wildlife reserves and wilderness areas. Trees species whose seeds are spread by wind may not be able to migrate fast enough to keep up with climate shifts and would die out.

4.3 Effects of Global Warming in Nepal 1.

Glacier Lake Outburst Flood (GLOF)

Global climatic change during the first half of the twentieth century has had a significant impact on the high mountainous glacial environment. Many big glaciers melted rapidly forming a large number of glacial lakes. Due to an increase in the rate of ice and snow melt; the accumulation of water in these lakes has been increasing rapidly. Sudden discharge of large volumes of water with debris from these lakes causes glacial lake outburst floods (GLOFs) in the valleys downstream. These result in serious death tolls and destruction of valuable natural resources such as forests, farms, and costly mountain infrastructures. The GLOF event that occurred on 4 August 1985 from Dig Tsho (Langmoche) glacial lake destroyed almost completely the Namche Small Hydropower Plant (estimated cost of US $ one and a half million), 14 bridges, cultivated lands, and so on. Five GLOF events occurred in Nepal from l97l to 1998 according to the records and, based on the study of satellite images, evidence of other occurrences in the past has been found. Six GLOF events (1935 - 1981) originating from Tibet, China, were reported to have damaging effects inside the Koshi River Basin in Nepal. A recent inventory carried out by ICIMOD and UNEP/EAP-AP shows that there are 3,252 glaciers covering a surface area of 5, 323 sq. km and, 2,315 glacial lakes out of which 26 potentially dangerous glacial lakes are in Nepal. Field studies of the six glacial lakes (Tsho Rolpa, Imja, Thulagi, Lower Barun, Dig Tsho, and Tam Pokhari) in Nepal have been carried out by different organizations. Similarly, the inventory shows that in Bhutan there are 677 glaciers covering 1,316 sq. km and 2,674lakes, out of which 22 are potentially dangerous (ICIMOD/UNEP/EAP-AP 2000). 2.

Melting of Snow The evidences of climate change have been all around us, from huge scars gouged in the landscapes by sudden, glacial floods to the lakes swollen by melting glaciers' It is found that quite rapid and significant changes in the ice fields are found accelerating over the past 20 years. Rapid melting of snow has also led to the receding of the snowline and glacial rivers "The Rikhasambha glacier river, located in the north-western Dhaulagiri valley, has receded 100 meters between 1974 and 1994.Every year the number of people dying in floods and landslides has been increasing. Components of Environment 42

3.

Flood and Landslide Floods are common and mostly natural disasters. When rivers overflow their banks, they cause damage to lives, property, infrastructure and crops. Floods usually are local and short-lived events that can happen suddenly and sometimes with little warning or no warning. They usually, are caused by intense storms that produce more runoff than an area can store or a stream can carry within its normal channel. Rivers can also flood its surroundings when the dams fail; when ice or a landslide temporarily blocks the course of the river channel, or when snow melts rapidly. Landslide is the descent of mass of earth and rock down a mountain slope. Landslides may occur when the rain water and melting snow shrink through the earth on top of a slope seep through cracks or porous spaces in underlying sand/stone and encounter a layer of slippery material, such as shale or clay inclined towards the valley. The glaciers would continue shrinking, and that the melt waters would trigger floods sending huge quantities of water, rubble and mud down the valleys, thus resulting in the huge landslides.

4.

Impact on Plants and Animals Many species of plants and animals live in very sensitive ecological niches even small changes in temperature or precipitation may have significant impacts on the organisms' ability to survive. Since all species are linked in complex food webs and habitat, impacts on one species always affect others. It is extremely difficult to predict how those effects will evident themselves. Changing the life cycles of some key species in food chains may well affect the huge circle of living things. Polar bears and other animals in the polar region are especially vulnerable to the effects of global warming. These animals are uniquely adapted to their environment and for them migration to other regions is not possible. Animals in warmer regions may shift their ranges toward the poles and to higher elevations when the global temperature increases. Plants and animals find it difficult to escape from or, adjust to the effects of global warming. Scientists have already observed shifts in the lifecycles of many plants and animals, such as flowers blooming earlier and birds hatching earlier in the spring. Many species have begun shifting from their original places due to warmer temperatures. With further warming, animals will tend to migrate toward the poles and up mountain sides toward higher elevations. Plants will also attempt to shift their ranges, seeking new areas as old habitats grow too warm. In many places, however their development will prevent these shifts. Species that find cities of farmland blocking their way north or south, may become extinct. Species living in unique ecosystems, such as those found in polar and mountaintop region are especially at risk because migration to new habitats is not possible. For example, polar bears and marine mammals in the Arctic are already threatened by dwindling sea ice but have nowhere farther north to go.

4.4 Controlling measures of the global warming and climate change Global warming and climate change is a worldwide problem. International efforts have been made towards reducing the amounts of gas emissions. However, climate changes have already begun, and their impacts will increase significantly over coming decades no matter how successful the efforts will be in reducing emissions. Components of Environment 43

1.

Control of Greenhouse Gas

Temperature increase is symbiotic effects of greenhouse gases. Most of the gases evolve from industrial countries. In order to reduce such gases, the utilization of fuel should be reduced and some other better alternative sources of energy should be developed. Each industry that evolves greenhouse gases should have a treatment plant. Developed countries should assist with developing countries to reduce such gases. 2.

Expansion of Forest Area

Conservation of the existing forest resources as well as plantation on remaining land reduces land erosion. Forest also conserves the water resources and helps to keep ecological balance. They also help to reduce the level of atmospheric carbon dioxide evolved by human activities and equally reduce the rate of temperature growth. Thus they also help to reduce the climate change. 3.

Pollution Control

In order to minimize global warming, there should be initiation of pollution control. Poor sanitation and degraded materials produce carbon dioxide, sulphur dioxide, and ammonia gases. So, there should be proper management of solid wastes as well as other pollutants at the local level, the national level and the international level as well. 4.

Conservation of Water Resources

Water resources play a vital role in balancing temperature. Oceans are enormous resources of water, which absorb a certain amount of CO 2. They reduce the rate of depletion of the ozone layer. Water resources also reduce desertification, which in turn reduces the rate of climate change. So, the conservation of water resources should be initiated from all sectors. 5.

Development of Alternative Energy

Since the fossil fuels produce greenhouse gases, their use should be minimized. In cases of developing countries, most of the rural people use agricultural residues, cow dung, coal, etc., which produce more carbon monoxide gas. Instead of using such fuels, the government should encourage the use of alternative sources of energy like electricity energy, solar energy, etc. It is also important to make people aware of using alternative sources of energy. 6.

Policy Formulation and implementation

In order to reduce the production of greenhouse gases, a policy against greenhouse gases should be formulated and implemented correctly. The conservation of resources is the most important factor in climate change. The International Convention in opposition to climate change and global warming should be followed successfully. 7.

Public Awareness

People of the locality must be made aware about the effect of the climate change and the global warming. All the people must be educated about the ways to minimize the effect of the climate change and global warming by the different ways like media, campaign program etc.

EXERCISE A.

Very short answer question: 1) Define climate change. 2) Define Global warming. 3) State any one natural cause of climate change. 4) State any one greenhouse gas that causes global warning. Components of Environment 44

5) 6)

Define GLOF. Define soot.

B.

Short answer question: 1) Explain the causes of climate change in brief. 2) Describe the causes of global warming in brief. 3) List different effects of the climate change. 4) What are green house gases? Explain how they cause global warming. 5) Define twomey effects and Albrecht effect in global warming.

C.

Long answer question: 1) What is global warming? Explain different causes of global warming. Also List the effect of the global warning. 2) Explain the effects of the global warning in Nepal in detail. Also list different controlling measures for global warming. 3) What is climate change? Explain cause and consequences of climate change.

D.

Practical problems: 1) Write a report on the impact of the climate change around your place, with the help of the elder people or by audio/visual material or field visit. 2) Write a report on the impacts of global warming with the help of the elder people or by audio/visual material or field visit.

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UNIT Natural Resources: Water and Soil 5.1 Water 5.1.1 Introduction Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state (water vapor or steam). Water also exists in a liquid crystal state near hydrophilic surfaces. Water covers 70.9% of the Earth's surface, and is vital for all known forms of life. On Earth, 96.5% of the planet's water is found in oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water bodies, and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air), and precipitation. Only 2.5% of the Earth's water is freshwater, and 98.8% of that water is in ice and groundwater. Less than 0.3% of all freshwater is in rivers, lakes, and the atmosphere, and an even smaller amount of the Earth's freshwater (0.003%) is contained within biological bodies and manufactured products.

5.1.2 Importance of Water Pure water is an odorless, tasteless, clear liquid. Water is one of nature's most important gifts to mankind. Essential to life, a person's survival depends on drinking water. Water is one of the most essential elements to good health -- it is necessary for the digestion and absorption of food; helps to maintain proper muscle tone; supplies oxygen and nutrients to the cells; rids the body of wastes; and serves as a natural air conditioning system. Health officials emphasize the importance of drinking at least eight glasses of clean water each and every day to maintain good health. Water is the major components of living being. Importance of water can be summarized as below: (a)

(b) (c) (d) (e) (f) (g) (h)

About fifty to ninety percent of the weight of living organism consists of water. Protoplasm, the basic material of living cells, consists of a solution of fats, carbohydrates, proteins, salts, and similar chemicals. The function of water is significant in the structure of an animal body. It consists of more than seventy percent of water. In our daily life, water is used for drinking purpose. In lack of drinking water, we cannot live. In dry seasons, we require more water. We need water in household uses such as washing, cooking, cleaning, etc. Water is also important for industries like cotton, garment, paper etc. We need water for irrigation. Water plays a vital role in the production of crops. During the photosynthesis process, green plants absorb water with the help of their roots. Photosynthesis is not feasible without water. Water also acts as a universal solvent. There are a number of things, which are soluble in water. The blood in animals and juice in plants consists of large amount of water. It serves to transport food throughout the body as well as to eliminate the waste materials out of the body. Components of Environment 47

(i) (j) (k) (l) (m)

Water also plays a key role in the metabolic breakdown of essential molecules like proteins and carbohydrates. This process, called hydrolysis, occurs frequently in living cells. Water is used to perform daily activities like washing, cleaning, cooking. Water is used to generate electricity. Water is used for transportation. Water is used for recreational activities.

5.1.3 Sources of water Life is possible on earth due to the presence of water. Nearly three-fourths of the earth's surface is covered with water. Water is also found below the earth's surface. It is present in air in the form of water vapour. About 70 per cent of the human body is water. The bodies of all plants and animals contain water. Major sources of water are discussed below: 1.

2.

Rain water: Rain is the precipitation of liquid drops of water. Raindrops normally have a diameter greater than 0.5 mm. They vary in size up to about three mm in diameter, and there rate of fall increases up to 7.6 mm per second with their size. Larger drops have a tendency to be compressed and broken into smaller drops by rapid fall through the air. The amount of volume of rainfall is expressed as the depth of water that collects on flat surface, and is measured in rain gauge to nearest 0.25 mm. Surface water: When rain falls on the land, two forces take steps on it. One is the earth’s gravity, which pulls the water downwards through any open path. The second force is the attraction between water molecules and other materials.

The surface water is found in different forms such as rivers, lakes, ponds, streams, waterfalls and seas: (a)

River: A river is a natural water course, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. The sources of river are mostly rainwater, melting of snow and underground water. Some major rivers of Nepal are Saptakoshi, Saptagandaki, Mahakali, Karnali, Rapti, Kankai and Bagmati. The water flow in the river is high in the rainy seasons whereas it is less in the winter seasons.

(b)

Lake: Lake is a large, internal body of clean or saline water. Many geological processes, such as buckling of stratified rock into large folds, displacement of large masses of rock by faults, and blocking of valleys by landslides, form lakes. Lakes are also formed by glaciations. Glaciers shape out large basins by measuring up bedrock and redistributing loose material. The supply of the lake water is atmospheric precipitation (rainwater) that reaches the lake directly and by means of springs, rivulets and rivers. Lake form and evaporate over the course of long geological time.

(c)

Pond: Water is stored in a low antidotal area, which may be natural or artificial which is called pond. It may be small or large in area. The source of pond water is atmospheric precipitation (rainwater) that reaches the pond directly and by means of springs.

(d)

Rivulet: Rivulet is produced by rainwater and by melting of the snow. Rivulets may be small or large. Sometimes rivulets run only in the rainy seasons whereas some run frequently. The volume of water is smaller in the spring seasons whereas it is larger in the summer seasons.

(e)

Waterfall: The fall of water from the hill to low altitude due to gravitational force is known as waterfall. Some waterfalls are regular and some are irregular. The volume of water flow varies with season. The waterfall makes the surroundings damp. The Patale Chhango (Davy’s fall) in Pokhara, is an example of waterfall. Components of Environment 48

(f)

3.

Sea: Sea is a general designation for all the salt water in the particular oceans and seas that cover a large area of the surface of the earth. The name is particularly given to bodies of salt water (e.g. the Mediterranean Sea) that are partially surrounded by land and are smaller than ocean to which they are normally associated. The name is also used to choose inland bodies of salt water.

Davis Falls

Ground Water: It makes larger fresh water reservoirs next to glaciers. A Fig :Close view of Davis Falls of Pokhara precipitation infiltrates the ground and fills the pores in soil and rocks. Upper soil layers that hold both air and water are also called the zone of aeration. Moisture for plant growth mainly comes from these layers. This layer may be shallow or quite deep depending on the amount of rainfall, soil type and surface topography. Lower soil layer where all available soil and rock spaces are filled with water is called the “zone of saturation”. The top of this layer is called water table, which is not flat but moves slowly according to surface topography and surface structure. It is also varies through seasons, rising and falling according to precipitation and infiltration rate. Porous, water bearing layer of sand, gravel and rock are called ‘aquifers’. They are always underlined by impermeable layers of rocks or clay that keep water from seeping out at the bottom. Aquifers yield an economically significant amount of water.

4.

Most aquifers are replenished naturally by rainfall which percolates down through soil and rock called natural recharge. Areas in which infiltration into an aquifer occurs are called ‘recharge zone’. Ground water moves from the recharge area through an aquifer and out to a ‘discharge area’ (well, spring, lake, hot spring, stem or ocean) as part of water cycle. The directions of flow of ground water from recharge area depend on flow gravity, pressure and friction. (a) Well: The soil absorbs the rain water, when it is situated to a point; it flows down and collects in a low altitudinal point. It is called well. The water level of the well is high in the rainy season whereas it is low in the winter season. The water in the well is natural, and the freshness of water depends on the surrounding area. (b) Tube-Well: Due to the shortage of surface water in urban area, people pump the ground water. Some pull water automatically and some do by electricity. In Terai region, the water is pumped for irrigation by using tube-wells. Several industries pump the ground water with the help of electric pumps. (c) Wetlands: Bogs, swamps, wet meadows and marshes play an important but ignored role in water cycle. Luxuriant plant growth in these places stabilizes soils and prevents surface run off so that more water infiltrates into aquifer, resulting into year round stream flow. When wetlands are drained, filled or disturbed in any other ways, their natural water absorbing capacity is lost and surface water runs off quickly resulting in flood and erosion during the rainy season and dry or nearly dry during rest of the time of the year. This has a disastrous effect on biological diversity, productivity, as well as on human affairs. The atmosphere It is the smallest of the major water reservoirs of the earth in terms of volume (0.01%) while water makes up only a small amount (four percent maximum at normal temperature) of the total Components of Environment 49

5.

6.

volume of air, movement of the water through the atmosphere provides the mechanisms for distributing fresh water over the land mass and replenishing terrestrial reservoirs. Desalination Desalination is an artificial process by which saline water (generally sea water) is converted to fresh water. The most common desalination processes are distillation and reverse osmosis. Desalination is currently expensive compared to most alternative sources of water, and only a very small fraction of total human use is satisfied by desalination. It is only economically practical for high-valued uses (such as household and industrial uses) in arid areas. The most extensive use is in the Persian Gulf. Frozen water Several schemes have been proposed to make use of icebergs as a water source, however to date this has only been done for novelty purposes. Glacier runoff is considered to be surface water. The Himalayas, which are often called "The Roof of the World", contain some of the most extensive and rough high altitude areas on Earth as well as the greatest area of glaciers and permafrost outside of the poles. Ten of Asia’s largest rivers flow from there and more than a billion people’s livelihoods depends on them. To complicate matters, temperatures are rising more rapidly here than the global average. In Nepal the temperature has risen with 0.6 degree over the last decade, whereas the global warming has been around 0.7 over the last hundred years.

5.1.4 Measures for the conservation of the water resources Sensible and careful use of natural resources by human is called conservation. Hence, conservation of water resources means wise and sensible use of water resource. Water resource must be used in proper way. There is only about 2% fresh water. So, if we want to have drinking water in proper amount, its quality should be maintained and it should not be exploited. Protection of local water sources is very vital for maintain sustainability of future generations. Some ways of protecting local water are treating wastewater (sewage) before disposing into local water bodies and protection of the sources of water. There are various measures of water resources conservation. Development of water resources is not an end by itself. It is a means to end. The end is to alleviate poverty and improve quality of life while protecting crucial ecological services performed by ecosystem. Achieving water security is essential for sustainable development which could be possible only with a radical shift in our thoughts and radically improved governance. Like other natural resources, some reduction, reuse, recycling and regeneration policy could help the conservation of water resource. Water resources can be managed and conserved to a large extent by adopting the following strategies: (i) (ii) (iii)

(iv)

(v)

Proper use of water: Water should be used only in required amount. It should not be wasted. Exploitation of water should be strictly prohibited. Control of water pollution: Water pollution deteriorates quality of water. Polluted water is of no use. So, preventive measures should be applied to control water pollution. Conservation of forest: Forest plays a very important role to control surface runoff. Forest enhances infiltration. It helps to store more water flowing through earth surface and there will be continuous supply of water through different sources. Watershed management: Watershed means the land area that delivers the sediments and dissolves substances through small streams to a major stream. Greenery should be maintained in the watershed. It delete contributes continuous flow of water in the stream. Awareness: People should be made aware about importance of water. They should be informed about the way to conserve water resources.


5.2 Soil 5.2.1 Introduction

Soil is defined as the top layer of the earth’s crust. It is formed by mineral particles, organic matter, water, air and living organisms. It is in fact an extremely complex, variable and living medium. It is a major component of the lithosphere. It is a source of nutrients necessary for living beings. It forms about one-fifth of the earth's surface covering about 13,393 million square hectares. About 36% of the land surface is covered by human dwellings, factories, roads, railways, industries etc. Similarly about 33% of the land mass is covered by forests. About 11% of the remaining land mass is arable. It is estimated that it takes about low years to 400 to from one centimeter of soil. The soil is a complex mixture of weathered mineral roach, partially decomposed organic molecules and a host of living organisms. It can be considered as an ecosystem by itself.

5.2.2 Importance of the land resources Land is obviously important because we would not have anything to stand on without land. Without land, we would not be able to plant trees, food crops and hence, we would not be able to eat or have shelter to rest from the sun. In short, our land is just as important as any other element in our planet, we are all connected in the planet and or land is one of the most basic elements in our lives. Aside from providing for a place for seeds, plants and trees to grow our land is like a measuring device that tells us the overall health of an area or a part of land. Living things like animals, leaves, seeds and other organic matters decompose on the soil providing organic matter that fattens up the soil; these in turn make plant grow healthier which animals that are eaten by human being in turn, eat. The importance of land is discussed below: 1. 2. 3. 4. 5. 6. 7. 8.

Food: We use land for the cultivation of food grains. Water: Land is the source of the ground and underground sources of drinking water. Waste Disposal: On land we can throw the waste matter which helps to recycle the waste matter and make useful product. These matters are used by green plants as food. Living Spaces: On land, different kinds of most important natural resources are found. By using these things, we can survive; so, land is the living spaces. Industrial and Commercial Zones: We can establish the different kinds of industries in different parts of land. It helps in economic development. Electrical Energy: On land, we can establish the Power plants and we can generate the electricity. Recreational and Research Zone: Parks, woodlands, watery ways and mountains are found on different parts of land, which are recreational and research zones. Transportation System: We can make road and other way it helps in the transportation systems.

5.2.3 Soil Profile Soil profile is the term used for the vertical section of earth crust generally up to the depth of six feet or up to the parent materials to show different types of horizons of soil for the study of soil in its undisturbed state. It is made up of a succession of horizontal layers or horizons. Each of which varies in thickness, color, texture, structure, consistency, porosity, acidity and compositions. Soils have four horizons: an organic or O-horizon and three minerals (A, B, and C) horizons: some scientists recognize also D-horizon in which rocks are in an active weathering state in between the C and R-horizons. The R-horizon is the consolidated bedrock on a soil profiles. O horizon The "O" stands for organic. It is a surface layer, dominated by the presence of large amounts of organic material in varying stages of decomposition. The O horizon should be considered distinct from the layer of leaf litter covering many heavily vegetated areas, which contains no weathered mineral particles and is not part of the soil itself. O horizons may be divided into O 1 and O2 categories, Components of Environment 51

whereby O1 horizons contain decomposed matter whose origin can be spotted on sight (for instance, fragments of rotting leaves), and O2 horizons containing only well-decomposed organic matter, the origin of which is not readily visible. P horizon These horizons are also heavily organic, but are distinct from O horizons in that they form under waterlogged conditions. The “P” designation comes from their common name, peats. They may be divided into P1 and P2 in the same way as O Horizons. This layer accumulates iron, clay, aluminium and organic compounds, a process referred to as illuviation. A horizon The A horizon is the top layer of the soil horizons or 'topsoil'. This layer has a layer of dark decomposed organic materials, which is called "humus".The technical definition of an A horizon may vary, but it is most commonly described in terms relative to deeper layers. "A" Horizons may be darker in color than deeper layers and contain more organic material, or they may be lighter but contain less clay or sesquioxides. The A is a surface horizon, and as such is also known as the zone in which most biological activity occurs. Soil organisms such as earthworms, potworms, arthropods, nematodes, fungi, and many species of bacteria and archaea are concentrated here, often in close association with plant roots. Thus the A horizon may be referred to as the biomantle. However, since biological activity extends far deeper into the soil, it cannot be used as a chief distinguishing feature of an A horizon. E horizon “E”, being short for eluviated, is most commonly used to label a horizon that has been significantly leached of its mineral and/or organic content, leaving a pale layer largely composed of silicates. These are present only in older, well-developed soils, and generally occur between the A and B horizons. In regions where this designation is not employed, leached layers are classified firstly as an A or B according to other characteristics, and then appended with the designation “e” (see the section below on horizon suffixes). In soils that contain gravels, due to animal bioturbation, a stonelayer commonly forms near or at the base of the E horizon. The above layers may be referred to collectively as the "solum". The layers below have no collective name but are distinct in that they are noticeably less affected by surface soil-forming processes. B horizon The B horizon is commonly referred to as "subsoil", and consists of mineral layers which may contain concentrations of clay or minerals such as iron or aluminium oxides or organic material moved there by leaching. Accordingly, this layer is also known as the "illuviated" horizon or the "zone of accumulation". In addition it is defined by having a distinctly different structure or consistency to the A horizon above and the horizons below. They may also have stronger colors (is higher chroma) than the A horizon. As with the A horizon, the B horizon may be divided into B 1, B2, and B3 types under the Australian system. B1 is a transitional horizon of the opposite nature to an A3 – dominated by the properties of the B horizons below it, but containing some A-horizon characteristics. B2 horizons have a concentration of clay, minerals, or organics and feature the strongest pedological development within the profile. B3 horizons are transitional between the overlying B layers and the material beneath it, whether C or D horizon. The A3, B1, and B3 horizons are not tightly defined, and their use is generally at the discretion of the individual worker. Plant roots penetrate through this layer, but it has very little humus. It is usually brownish or red because of the clay and iron oxides washed down from A horizon. Components of Environment 52

C horizon The C horizon is simply named so because it comes after A and B within the soil profile. This layer is little affected by soil forming processes (weathering), and the lack of pedological development is one of the defining attributes. The C Horizon may contain lumps or more likely large shelves of unweathered rock, rather than being made up solely of small fragments as in the solum. "Ghost" rock structure may be present within these horizons. The C horizon also contains material. It forms the framework of the soil. The A and B layers are formed by this layer. D horizon D horizons are not universally distinguished, but in the Australian system refer to "any soil material below the solum that is unlike the solum in general character, is not C horizon, and cannot be given reliable designation and may be recognized by the contrast in pedologic organization between it and the overlying horizons." R horizon (bedrock) R horizons denote the layer of partially weathered bedrock at the base of the soil profile. Unlike the above layers, R horizons largely comprise continuous masses (as opposed to boulders) of hard rock that cannot be excavated by hand. Soil texture Soil texture is a qualitative classification tool used in both the field and laboratory to determine classes for agricultural soils based on their physical texture. The classes are distinguished in the field by the 'textural feel' which can be further clarified by separating the relative proportions of sand, silt and clay using grading sieves: Fig: USDA and UK-ADAS textural triangle The Particle Size Distribution (PSD). The class is then used to determine crop suitability and to approximate the soils responses to environmental and management conditions such as drought or calcium (lime) requirements. A qualitative rather than a quantitative tool it is a fast, simple and effective means to assess the soils physical characteristics. Name of soil separate Clay Silt Very fine sand Fine sand Medium sand Coarse sand Very coarse sand

Diameter limits (mm) ( USDA classification) less than 0.002 0.002–0.05 0.05–0.10 0.10–0.25 0.25–0.50 0.50–1.00 1.00–2.00

5.2.4 Types of the soil of Nepal Soil may be defined as a thin layer of earth crust which serves as a natural medium for the growth of plants. It is unconsolidated mineral matter that has been subjected to influence genetic and Components of Environment 53

environmental factors-parent materials; climate organism and topography; all acting over a period of time. Soil differs from the parent material in the physical, chemical and biological properties. Thus, some soils are red, some are black and some are deep and some are shallow. The components of soil are mineral materials, organic matter, water and air. The proportions of these vary and together from a system for plant growth. Soil is formed by the weathering of rocks found in the earth crust and mixed with decayed plant and animal remains. According to the structure of the earth surface, characters of original rocks and climatic differences, the soil of the country also have varied compositions; colour and other features, for convenience, the soils of Nepal are grouped into three types, e.g. Himalayan, Mountain and Terai soil which are given below: 1.

Alluvial soil Soils of Terai region are alluvial soils transported by rivers from the hills. The soils have round, smooth, soil particles and are stratified. Alluvium soils posses’ strata of finely grounded silt, clay or sand. Sometimes alluvium is very deep and has been reported to reach a depth of more than 2000m. The soils are pale yellow or dark grayish brown in colour and vary in texture from sandy loam to sandy clay loam. Terai soils are poor in nitrogen but have adequate amounts of alkalis, potassium and phosphorus. The soil is most fertile in comparisons with other soil. 2.

Sandy boulder soil This kind of soil is found in Bhabar region, mostly gravel and pebbles and hence is highly porous, water of the mountain streams disappears here to reissue again in the form of springs in the Terai. Coarse gravel and boulders mixed with ferrous sand and clay make the soil of this region. Because of the poor quality of the soils, we can hardly grow any crop in this region but it is good for sal (Shorea robusta) forest. 3.

Lacustrine soil Valleys in the mid-mountain have sand and silty alluvial soil over older lake deposits, such soil is called lacustrine soil. This type of soil is of recent origin and in a zonal (without distinct soil profile). It has a lot of organic compound and is black in color (Kalimati). This soil also possesses a considerable amount of potash and also little calcium. It is more clayed than silt in composition. In other valleys, type varies from silt loam to clayed loam. The water table is rather high and soil may be acidic or alkaline, it is good for crops such as Kathmandu valley and Pokhara valley. 4.

Residual soil In most of the parts of Mahabharat region, we can get residual soil which is red or yellow in colour. As the soil is formed from the hard rocks, it contains very little plant nutrients. Crops which can be grown in dry soil as millet, buckwheat, and maize, are suitable for this soil. It contains little organic matter and is formed quite often by the breakdown of limestone, gneiss, quartz etc. The rock pieces are mica, schist and being new, the soils (lithosphere) are generally poor for agriculture. 5.

Glacial soil In some parts of the Bhitri Himalaya, we can get glacial soil, which is very fertile but is most of these parts; we can get only sandy soil. Because of the lack of rain in this region, soil is dry and hard, which is not suitable for cultivation. In the inner Himalayan valleys soils are covered with snow during the winter but warm enough to grow barley and potato during summer months. At still higher altitude there is Perma forest (frozen soil).

5.2.5 Soil Erosion Soil development, soil removal and soil re-generation are normal natural processes. In this section, the process of soil removal will be dealt in some detail. The wearing a way of land surface by running water, wind, waves, moving ice, etc. is a normal geological process called erosion. This natural geological erosion in an environment without disturbance of human activity is known as soil removal. It is a slow process of surface plantation which is a normally known as soil removal. It has Components of Environment 54

given rise to various features of landscape such as valleys, plateaus, plants, deltas, coastal plains etc. Normal erosion assisted by weathering helps soil formation. Normal erosion at a place is at lower rate than at which the new soil is being formed from the parent material lying beneath. In our context, the term soil erosion is referring to the accelerated process of soil removal as a consequence of human interference with normal equilibrium between soil development and soil removal. In this process, such destruction of soil leads to land degradation which ultimately may results in farm abandonment, disintegration of rural communities, increase in relief load and ultimately decline of the nation. But that is not the end of the natural cycle. Once again volunteer vegetation comes back on abandoned areas. Gradually its density increases and the soil building process begin slowly. A depth of six inches to nine inches of the normal top soil gets recreated through nature’s slow but persistent effort. Vegetation too continues to progress slowly, ultimately growing into forest. But this competition of cycle, from a washed out land to regenerated soil and thick forest cover, may involve a long period of time. Problem of soil erosion is serious in the hills. The rock, destruction of forest trees, shrubs, and sal kinds of vegetation leads to the loss of large tracts of fertile land every year during monsoon. Annually, 1.7 mm of fertile top soil gets lost in Nepal. Every year about 240 million tons of soil moves through rivers from Nepal to the bay of Bangal. It leads to desertification and decline in land productivity. The rivers originating from the high Himalayan regions is Tamor 38.0, Sunkoshi 21.0, Saptakoshi 15.0 and Arun 7.6 tons sediments per hector per year. The koshi River carries a load of 9.9 million cubic meter of silt every year. There are two major types of erosion. They are geological erosion and accelerated erosion. Geological Erosion Such erosion is said to be in equilibrium with the soil forming process. It occurs under the protective cover of natural vegetation being completely undisturbed by biotic interference. Such slow eroding process has developed the present topographic features like stream channels, valleys, and canyons, through the effect of water, wind, temperature changes and living organisms. Accelerated Erosion When there are disturbances in the existing equilibrium in nature, accelerated erosion takes place. The agencies responsible for such disturbances are humans or animals. They interfere with natural equilibrium through activities like wrong land management, over exploitation of forests and natural vegetation, over grazing, etc.

5.2.6 Soil conservation Soil conservation is the soil quality maintenance which involves reducing soil, erosion, preventing depletion of soil nutrients and restoring nutrients already lost by erosion, leaching and over cropping. The art of soil conservation is based on certain basic principles which include:  Protection of soil from the impact of water drops.  Prevention of water from collecting and moving down the slope in a narrow path.  To slow down the force of water movements when it flows down the slope.  To make more water to infiltrate into the soil by increasing the size of the components of soil particles.  To reduce the wind velocity near the soil surface by growing plant cover, ridging the soil etc.  By applying conservation tillage farming.  By applying sustainable agricultural practices.

Methods of Soil Conservation Following are some of the common methods: 1.

Contour farming It is the plowing and planting of crops in rows across, rather than up and down the slopped contour of the land. Components of Environment 55

2.

Strip farming In this method a row of crop like corn alternates in stripes with a soil saving cover such as grass of grass-legume combined which completely covers the soil and thus reduces erosion.

3.

Terracing It is used in steeper slopes. The slope is converted into a series of broad, nearly level terraces that run across the land contour, with short vertical drops from one terrace to another. Terracing retains water for crops at all levels and cuts soil erosion by controlling run off. In areas of high rainfall diversion ditches must be built in each terrace to permit adequate drainage. The edges of the terraces are planted with soil binding useful plant species.

4.

Growing perennial plants Tea, coffee or many other crops that do not have to be cultivated every year should be planted to protect certain unstable soil on sloping sites or water courses.

5.

Alley cropping or Agro-forestry It is a form of inter cropping in which crops are planted between hedge rows of trees or bushes that provide fruit or fodder or fuel wood.

6.

Gulley reclamation Gullies created by water runoff in sloping bare land can be restored by this method. Small gullies can be seeded with fast growing plants such as oats, barley and wheat for the first season. While deeper gullies can be dammed to collect silt and litter can also be planted to stabilize the soil and channels can be built to divert water from gully and prevented further erosion.

7.

Stream bank protection To grow vegetation along the side of riverbank, to construct drains, stone concrete pitching etc. to check the cutting and caving of river bank.

8.

Forestation Planting trees are the most effective way of checking soil erosion as well as means to meet the acute shortage of firewood, fodder and green manure. This prevents both water and wind erosion. Any fast growing multipurpose tree species suited to local climatic conditions should be used for this purpose.

9.

Wind breaker shelter belts Long rows of trees are planted to partially-block the wind. These are especially effective if uncultivated land is kept covered with ground vegetation. Wind breaks also provide living place to birds, pollinating insects and other animals.

EXERCISE A.

Very short questions 1) What percentage of the earth surface is covered by the water? 2) State any ore sources of underground water. 3) Define sail profile. 4) Define strip farming. 5) Define terrace farming. Components of Environment 56

B.

Short answer questions 1) Explain the importance of water resources. 2) What are water resources? State different Sources water. 3) Explain different ways of Conservation of water resources. 4) Explain how public could enhance the conservation of water resource. 5) What is underground water? Explain different sources of underground water. 6) What is soil resource? Explain importance of soil resource. 7) Explain soil profile in brief. 8) State different types of the soil found in Nepal and explain any one of them. 9) Planting perennial species of plants helps to check soil erosion. Justify. 10) State different methods of soil conservation.

C.

Long answer questions 1) What is water resource? State and explain different types of the water resource. 2) What is soil consecration? Explain different types of the soil erosion and different ways to conserve soil.

D.

Practical problems 1) Visit a nearby water resource and write a report on conservation of the water resource. 2) Visit an area of the hilly region. Write a report about the condition of the soil and the ways to conserve the soil there.




UNIT Natural Resources: Indigenous Plants and Animals

6.1 Introduction In biogeography, a species is defined as indigenous or native to a given region or ecosystem if its presence in that region is the result of only natural resource, with no human intervention. Every natural organism (as opposed to a domesticated organism has its own natural range of distribution in which it is regarded as native. outside this native range, a species may be introduced by human activity; it is then referred to as an introduced species within the regions where it was anthropogenically introduced. An indigenous species is not necessarily endemic. In biology and ecology, endemic means exclusively native to the biota of a specific place. An indigenous species may occur in more than one locality. Due to its exceptional diversity of topographic, climatic, and agro-ecological conditions, Nepal is considered one of the richest biodiversity hotspots of the world, including about 200 indigenous fruit and nut species. These plants play a significant role, especially for the well-being of rural people by providing nutrition, household income and employment. Often, indigenous fruits and nuts are not domesticated or cultivated, but gathered from natural stands. However, many of these populations are said to be threatened and disappearing, due to deforestation and over-exploitation, among others.

6.2 Importance Indigenous plant and animal species are important natural resources that have been widely used by human beings. They have ethical, cultural, commercial, recreational and environmental values. These are intimately connected with our society, tradition, culture, education, economy, recreation and ecology. 1.

Ethical Importance: Ethically, we have no right to destroy indigenous species. Many followers of Buddhism believe it is wrong to kill animals. Some indigenous fruits and nuts have a high cultural value and are very important for celebrating the traditional religion. For example, fruits of the bel tree ( Aegle marmelos) are of cultural importance for the Newar tribe around Kathmandu Valley and other places in Nepal for 'lhee' or 'Bel Biwaha' (Ihee is the ceremony when young girls are supposed marry to a certain bel fruit.). The bel fruit symbolizes the Hindu God Shiva and this marriage is considered to be everlasting.

2.

Aesthetic Importance: If wildlife had no other value and were an economic detriment, it would still be worth preserving, for many people, for its sheer beauty and appeal to the human spirit. People go to national parks to watch as well as to study wild animals.

3.

Commercial Importance: Indigenous species can be more productive and economically profitable than domestic animal and life would be on the same ground. The areas allocated for the parks can be used commercially to farm fish.

4.

Ecological Importance: Ecology is the relationship between living beings and- their environment. All living things play an important role in maintaining the delicate ecological Components of Environment 59

balance of our earth. Wild animals are as much a part of nature as human beings are and they have a significant role in maintaining the ecosystem. 5.

Ecotourism: Indigenous species provide best means of sport and recreation. A country can earn a good amount of foreign currency by attracting tourists.

6.

Scientific Importance: Indigenous species have immense scientific importance in research. Any medicine or drug is generally first tested on animals. Our knowledge of the adaptation would have been incomplete without the knowledge of indigenous species which are widely used for the practical study by students of zoology, botany and environment. Thus, the indigenous species form an integral part of human life.

6.3 Some important indigenous Plants and animals found in Nepal Geographically, Nepal can be divided into three regions, namely Himalayan Region, Hilly region and Terai Region. The climate, Land, plant diversity etc. are found to be different in these regions. Due to this, our country is rich in bio-diversity. The animals and plants found in these regions are also different. Some important animals and plants found in different regions are as follows: Mountain Belt The Sherpa and Thakali are the chief inhabitants of Mountain belt. About 7.3 percent of the people live there. The vegetation related to agriculture is available in little quantity because this belt is not suitable for agriculture. Yet, the production of barley, potato, buckwheat is done. The people grow potato and green and leafy vegetables. Cultivation of apple is also done in this belt. Alpine type of forest is available in this belt. The coniferous type of plants and trees are available here being wet belt. The vegetation such as fir, Salla, Gobre Salla, Thegurne Salla, rhododendron, Bhojpatra, hyssop, wild garlic, etc. are found in this belt. There are various kinds of red rhododendrons. There are shrubs and trees with sharp points. This belt is supposed to be famous for important herbs like Timur, Panchaunle, Padamchal, Jatamasi, Atis, Bikhama and Yarsagumba. This belt is also famous for different coloured flowering plants. There are grazing and grass fields in different places. The biodiversity of birds and animals is limited due to cold climate of this belt. Musk deer, Himalayan Tahr, Red Panda, Ghoral, wild yak, snow leopard, Black Bear, sirow and other wild animals are found in this belt. Similarly, there are wild boar, leopard, Red deer, etc. also in this belt. The birds like Danphe, Monal, Chilme, Koklas, Kalij, Cheer, etc. are found in this belt. The people of this belt keep sheep, mountain goat, gaur, yak, etc. Plants in the Mountain Belt 1. Fir trees 6. Maple 2. Gobre Salla 3. Rhododendron 8. Bhoj patra 4. Devdar 5. Gurne salla 10. Elma Herbs (Medicinal Plants) in the Mountain Belt

7. Talis patra 9. Sprus

1. Bikhama 5. Jatamasi 2. Panchaunle 6. Timur 3. Atis 7. Yarsagumba 4. Padamchal Animals in the Northern Hilly Belt and Mountainous Belt of Nepal 1. Jharal

8. Munt Juk,

2. Sirow

9. Himalayan sheep

3. Ghoral

10. Wild yak

4. Pika

11. Snow Leopard Components of Environment 60

5. Red Panda

12. Wild dog

7. Musk deer

14. Yak

6. Wild boar

Birds in the Mountain Belt 1. Danphe 2. Monal 5. Cheer Pheasant6. Blood Pheasant 9. Chilme

3. Koklas 7. Kalij

13. Gaur

4. Pheasant 8. Luinche

Hilly Belt The settlement of the people is thin in this belt. There is about 46 percent population in this belt. The tribes as Rai, Limbu, Tamang, Magar, Gurung, Brahmin, Chhetri live here. The biodiversity is found more in this belt in comparison with other belts. There are thick and thin forests in this belt. There are forests of utis, katus and chilaune in this belt. There are cool temperature forests at the altitude ranging from 2000 metres to 3000 metres. Different kinds of plants and trees such as sal, simal, peepal, bar,bamboo, chilaune, katus, salla arc available in this belt according to hill face, altitude and land topography. The rhododendrons, kharsu, Devdar are found in higher altitudes. Similarly, there are also different kinds of plants and trees of fruits and flowers. In the upper part of the hilly belt, the cultivation of maize, barley, buckwheat, millet, soya bean, etc. is done. In the lower and plain part of this belt, the cultivation of paddy, maize, wheat, pulse and vegetables is done. The cultivation of fruits such as mango, pear, orange, lemon, banana is also done. There are different kinds of birds and animals in this belt due to land topography and vegetation diversity. The wild animals such as bear, leopard, panther, deer, monkey, wild cat, tiger, red deer, chital are found here. This belt is rich in different kinds of birds such as kalij, falcon eagle, kite, dove, parrot and others. Important herbs such as chutro, timur, tejpat, sarpagandha, bojho, kalo dhaturo, sugandhawal, etc. are found in this belt. Plants in the Hilly Belt l. Dhale katus 5. Rani Salla

2. Utis 6. Magnolia

3. Chilanue 7. Paiyun

4. Walnut

Herbs (Medicinal plants) in the Hilly Belt 1. Chutro

2.Kalodhaturo

5. Sugandhawal 6. Timur

3. Chitaito

4. Bojho

7. Beladonna

8. Tejpat

Animals in the Hilly Belt 1. Bear 2. Panther

3. Deer

4. Monkey

5. Wild cat

7. Red Deer

8. Chital

6. Leopard

Birds in the Hilly beat 1. Kalij 2. Falcon 5. Parrot 6. Eagle

3. Kite 7. Black Buck

4. Dive

Terai Belt The Terai belt is stretched from the south border to Mahabharat and Chure hills. The eastern part of this belt is wide and the western part is narrow. It is suitable for cultivation and forest due to hot Components of Environment 61

climate and alluvial soil. There are different kinds of vegetation, birds and animals and other creatures in this belt due to the biodiversity.46.7 percent of total population of the country live in this belt. Chaudhari, Rajbanshi, Tharu, Yadav, etc. are the old tribes of this belt. The Brahmin, Chhetri, lama, Tamang, Magar, of different tribes has migrated from Hill to Terai. The Terai belt has mixed settlement. This belt being fertile, the cultivation of paddy, wheat, tobacco, sugarcane, pulses, jute, etc. is done. The Terai belt is the store house of vegetation. The hot evergreen forest is available in the lower plain fields. There are hot deciduous forests in the lower ridge, plateaus, and valleys of Mahabharat hill. Hence, there are mainly sub-tropical deciduous forest and warm evergreen forest in the Terai belt. The plants and trees as sal, sissoo, saj, satisal, khayer, harro, barro, sindhure, simal, tamarind, plas, etc. are spread in different places from east to west. Similarly, grass field, river and rivulets, ponds, tanks at different places add splendour to this belt. Different kinds of birds and animals are found in this belt. This belt is the shelter of large mammals such as tiger, elephant, rhinoceros, wild buffalo, gaur, blue bull, leopard and different kinds of deer. Similarly, there are bear, monkey, wild pig, alligator, crocodile, python, Asiatic Rock python, etc. in this belt. This belt is suitable for peacock, wild fow, crane, falcon, dhanesh and stork. Such birds are in abundance in this belt. Fish is available in the water sources like rivers and rivulets of this belt. Plants in the Terai Belt 1. Sal 2. Sissoo 5. Karma 6. Asna 9. Chilaune 10. Saj

3. Simal 7. Katus 11. Peopal

Herbs in the Terai Belt 1. Harro 2. Barro 5. Asuro 6. Pipal

3. Rajbriksha 4. Amala 7. Sarpaghandha

4. Khayer 8. Utis 12. Jamun

Animals in the Terai Belt Animals in the Terai 1. Elephant 5. Wolf 9. Barking deer 13. Rhinoceros 17. Fox

2. Blackbuck 6. Tiger 10. Jackal 14. Swamp deer 18. Leopard

Birds in the Terai Belt 1. Luinche 3. Pigeon Some Flowers of Nepal 1. Lalupate 2. Asari 3. Laliguras

2. Peacock

3. Common langur 7. Spotted deer 11. Wild boar 15. Wild buffalso 19. Gaur 4. Kalij

4. Sloth bear 8. Crocodile 12. Wild dog 16. Samber deer 20. Porcupine

5. Sparrow

6. Water duck

2. Sun-flower 5. Marigold 6 Makhamali Phul

6.4 Endangered / Rare animals of Nepal An endangered species is a population of organisms which is facing a high risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters. The International Union for Conservation of Nature (IUCN) has calculated the percentage Components of Environment 62

of endangered species as 40% of all organisms based on the sample of species that have been evaluated through 2006. Many nations have laws offering protection to conserve endangered species: for example, forbidding hunting, restricting land development or creating preserves. Only a few of the many species at risk of extinction actually make it to the lists and obtain legal protection like Pandas. Many more species become extinct, or potentially will become extinct, without gaining public notice. Endangered plants species and animals species, are in danger of extinction, the dying off of all individuals of a species- over 34,000 plant species and 5,200 animal species around the globe are threatened with extinction, and many thousands become extinct each year before biologists can identify them. The primary causes of species extinct each year before biologists can identify them. The primary causes of species extinction or being endangered are habitat destruction, commercial exploitations, damage caused by non-native plants and animals introduced into an area, pollution and direct habitat destruction threatens the most species. Some of the animals including birds found in Nepal are endangered. They are listed as protected species and they are conserved. Some main endangered and protected species of animals are as follows: 1. One horned Rhinoceros Kingdom : Animalia Phylum : Chordata Class : Mammalia Scientific name : Rhinocerous unicornis Lifespan : 40 to 70 years Color : Light dark Body structure : Hairless body, folded skin Height : 1 to 2 m Weight : 2000 to 4000 kg Distribution : Chitwan, Bardiya, Shuklaphata National Park Rhinoceros is an endangered species in Nepal. Rhinos live in warm climate, and they are found in terai region only. In Nepal, they are conserved in Chitwan National Park. Some are shifted in Bardia National Park. It is estimated that there are 1735 to 2025 one-horned rhinoceros in the world. There are 466 rhinoceros in Bardia national park. Rhinos live in different habitats and feed in different ways. In Asia, the rhinos live in dense tropical forest, where they feed on leaves, twigs, and fruit. The Nepali rhino also browses on trees and shrubs, but instead of living in forest, it lives in flat, open areas. In rainy season, its main food is swampland grass, which can grow over 5 meter high. The species mainly inhabits in riverine grassland and occasionally utilize some adjacent woodland. Greater one-horned rhinos are grazes, although occasionally they consume browse. Even not grazing on land, animals like immerse them in water, where they also graze on aquatic grass-like plants. This species is the most amphibious of the living rhinos. Gestation lasts approximately 15-16 months, and mothers give birth to one calf every 1-3 years. Females reach sexual maturity between 5 and 7 years of age; males mature at approximately 10 years of age. Greater one-horned rhinos are usually solitary except for females with young. Males maintain loosely-defended territories. Components of Environment 63

2 Bengal Tiger Kingdom Phylum Class

: : :

Animalia Chordata Mammalia

Scientific name

:

Panthera tigris

Lifespan Color

: :

Body structure

:

Height Weight Special characteristic Distribution

: : : :

15 years Light yellow black stripes on golden color Large Head, long tail 0.95 to 1.25 m 180 to 280 kg Found in grassland of Terai / National Animal of India Chitwan, Parsa, Bardiya, Shuklaphata National Park

The tiger is the largest member of the family. Designed predators, tigers possess beauty, grace, and awesome power. Tigers are obligate carnivores. They prefer hunting large ungulates such as chital, samsar, gaur, and to a lesser extent also barasingha, water buffalo, nilgai. Among the mediumsized prey species they frequently killed wild boar, and occasionally hog deer and gray langur. Small prey species such as porcupines, hares and peafowl form a very small part in their diet. Due to the encroachment of humans onto their habitat, they also prey on domestic livestock. The tiger population in the Terai of Nepal is split into three isolated and vulnerable subpopulations-inhabiting Chitwan National Park and adjacent Parsa Wildlife Reserve, Bardia National Park and SuklaPhata Wildlife Reserve. The number of adult tiger has reached 155 after a serious decline. A survey conducted from December 2009 to March 2010 indicates that 125 adult tigers live in Chitwan National Park and its border areas covering 1,261 km2. Tiger fur is short and varies in colour from dark orange to reddish brown, with creamy white on the belly, neck, and inside of limbs. Dark brown or black stripes run vertically across the body. Stripe patterns are unique to individual tigers, and like fingerprints, in humans, stripes can be used to tell tigers apart. Tiger is a carnivore. It feed on wild animals such as spotted deer, wild bear; monkey etc. the incubation period of tiger is 105 days to 112 days and bears two to six cubs. The average life of the tiger is 20 years.

3. Impeyan Pheasant Kingdom Phylum Class

: : :

Animalia Chordata Aves

Scientific name

:

Lophophorus impejanus

Lifespan Color Body structure

: : :

6 to 8 years Covered with shiny colors Males have very long crest Components of Environment 64

Height Special character Weight Distribution

: : : :

0.4 to 0.7 m National bird of Nepal / State bird of Uttarkhanda 2 to 2.4 kg Mountain region

The males are adorned with beautiful metallic colors of green, purple, red and blue. They also have a large white patch on the rump. The breast and under parts are black and the tail is copper. Males also have a very long crest, much like a peacock. The male also have a bare patch of turquoise blue skin around the eye. The hens are attractive. They are basically brown overall, with black, buff and white streaks. Her throat is white and she has a short crest. Hens also have the blue patch around the eyes. First year male resemble the hens, but are larger and have black feathers on the neck and breast. Interesting Facts: The national bird of Nepal, commonly called the Impeyan after lady Impey who first kept them in captivity. Breeding season begins late April, These pheasants breed well in captivity and can be good parents. They start breeding in their second year, and the season usually starts in late April. The will nest on the ground or a hole in a rock face, with an average clutch of 3-5 eggs, and sometime as many as 23. The incubation period is 28 days. The habitat of the pheasant is the forest of Himalayan region. In Nepal, they are conserved in Sagarmatha National Park, Annapurna Conservation Area, Langtang National Park, SheyPhoksundo National Park, Makalu Barun National Park and conservation Area, Rara National Park, and Khaptad National Park.

4 .Golden Monitor Lizard Kingdom Phylum Class

: : :

Animalia Chordata Reptilia

Scientific name

:

Varanus flavescens

Lifespan Color Body structure Length Weight Habitat Special character

: : : : : : :

15 to 20 years Dark brown and little red Long 0.45 m 4 to 5 kg Mountain region Lives in water, pond near forest

Golden monitor lizard is a protected reptile found in Nepal. It is brown in colour. It has a small mouth. Its tail is pressed from left and right. Its head is small and fingers are small as well. Golden monitor lizard lives at branches of trees, dry wood and holes. It also lives under the stones. Wetlands e.g. paddy land, fishing pond, rivers, etc. are also habitat of the golden monitor lizard. Varanus flavescens has sub corneal teeth, scarcely compressed. Its snout is short and convex, measuring a little less than the distance from the anterior border of the orbit to the anterior border of the ear; canthus rostral is distinct. Its nostril an oblique slit, a little nearer to the end of the snout than to the orbit. Digits short, the length of the fourth toe, measured from its articulation with the tarsus to the base of the claw, not exceeding the length of the femur. The tail of the Yellow Monitor feebly compressed, keeled above. Abdominal scales smooth, in 65 to 75 transverse rows. From snout Components of Environment 65

to vent 1 foot 3 inches; tail 1 foot 8 inches. They are found in Flood plains of the Indus, Ganges and Brahmaputra rivers in India, Pakistan, Nepal and Bangladesh. The hatching period of golden monitor lizard is 240 to 270 days. It lays 20 to 30 eggs. Its average life is 15 to 20 years. 5. Musk Deer Kingdom Phylum Class Lifespan Color Height Weight

: : : : : : :

Scientific name

:

Body structure Distribution Special characteristics

: Long ears, short tail, no horn, tusk in male : At the altitude of 2700 to 4500 m in Nepal : Male has musk pouch. A male has 30-40 g musk

Animalia Chordata Mammalia 12 to 15 years Dark brown 0.5 to 0.6 m 10 to 15 kg

Moschus chrysogaster

Musk deer is a small, solitary deer of Nepal. It has no horns. The canine teeth of the male deer projected in the form of long tusk. The male is much hunted for its musk, a substance secreted by a gland located in its abdomen. The musk is used in perfume and in Chinese medicinal preparations. It is protected species in Nepal. Musk deer are found in the forest of Himalayan region. In Nepal, they are conserves in Rara National Park, Sagarmatha National Park, Dhorpatan Hunting Reserve and Makalu Barun National Park and Conservation area. They feed on leaves of plants, grasses, flowers etc. The incubation period of musk deer is 180 days and gives birth to one to two young ones. Its average life is 12 to 15 years. Musk deer is protected mammal and listed as an endangered species by the National Parks and listed by CITES in Appendix I for Afghanistan, India, Nepal and pakisthan, and in Appendix II for Bhutan and china.

5. Snow leopard Kingdom Phylum Class Scientific name Lifespan Body structure Height Weight

: : : : : : : :

Color

:

Special characteristic :

Distribution

:


Uncia uncia 8 to 9 years Long and flexible tail Large head, long tail Male 45 to 55 kg, female 35 to 40 kg. Black spots on light grey color Lives on feeding on wild deer, goat, musk deer, mouse. High Himalayan region

The snow leopard (Panthera uncia or Uncia uncia) is a moderately large cat native to the mountain ranges of Asia. Snow leopards occupy alpine and subalpine areas generally 3,350 and 6,700 Components of Environment 66

meters (10,990 and 22,000 ft.), above sea level in Central Asia. The Snow Leopard Survival Strategy (McCarthy et al. 2003, Table II) compiled national snow leopard population estimates, updating the work of Fox (1994). Many of the estimates are acknowledged to be rough and out of date, but the total estimated population is 4,080-6,590. However, the global snow leopard effective population size (those likely to reproduce) is suspected to be fewer than 2,500 (50% of the total population, or 2,040-3,295). In Nepal, they are conserved in Sagarmatha National Park, Annapurna Conservation Area, Dhorpatan Hunting Reserve, Langtang National Park, SheyPhoksundo National Park, and Makalu Barun National Park and Conservation Area. The body of Snow leopard is soft. It feeds on the wild sheep, rabbit, musk deer, domestic sheep, etc. It usually moves to very long range in search of food. The incubation period of snow leopard is 90 to 110 days. It gives birth to two cubs. Its average life is 8 to 9 years. 7. Gaur Kingdom Phylum Class

: Animalia : Chordata : Mammalia

Scientific name

:

Bos gaurus

Lifespan Color Height Weight Special characteristics Body structure Distribution

: : : : : : :

20 years Black shiny color 1.75 to 2.2 m 600 to 1000 kg Feeds on bark and leaves of trees in Churia range Large head, large and strong body Churia range, Parsa, Chitwan, Trijuga

The gaur is the largest species of wild cattle, bigger than the African buffalo, the extinct aurochs, and wild water buffalo. The domesticated form of the gaur, Bos frontalis, is called gayal or mithun. The gaur is an extremely large mammal. Gaur is the endangered animal found in Nepal. This species is found in India, Myanmmar, Nepal. Gaur is found in Churia region, Bhabar region, PersaChitwa, Trijuga of Nepal. Gaur are said to look like water buffalo at the front and domestic cattle at the back due to their heavily muscled and enlarged forequarters compared to their relatively small hindquarters. They are the heaviest and the most powerful of all wild cattle, and are among the largest living land animals. Gaur historically occurred throughout mainland South and Southeast Asia, including Vietnam, Cambodia, Laos, China, Thailand, Peninsular Malaysia, Myanmar, Bangladesh, Bhutan, Nepal, and India. Today, the species is seriously fragmented within its range, and regionally extinct in Sri Lanka. In Nepal, the gaur population was estimated to be 250–350 in the mid-1990s, with the majority in Chitwan National Park and the adjacent Parsa Wildlife Reserve. Population trends appeared to be relatively stable. The Chitwan population has increased from 188 to 296 animals in the years 1997 to 2007; a census conducted in Parsa Wildlife Reserve confirmed the presence of 37 gaur in May 2008.Wild gaur graze and browse on a wider variety of plants than any other ungulate species of India, with a preference for the upper portions of plants, such as leaf blades, stems, seeds and flowers of grass species, including kadam. Gaur has one calf (or occasionally two) after a gestation period of about 275 days, about nine months, a few days’ less than domestic cattle. Calves are typically weaned after seven to 12 months. Sexual maturity occurs in the gaur's second or third year. Breeding takes


place year-round, but typically peaks between December and June. The lifespan of a gaur in captivity is up to 30 years. 8. Leopard cat Kingdom Phylum Class

: Animalia : Chordata : Mammalia

Scientific name

:

Lifespan Color

: 13 years : Black spots on light yellow : 0.35 m : 3 to 4 kg : Feeds on small mammals and birds : Like small leopard, long legs : Mid hill and Terai region

Height Weight Special characteristics Body structure Distribution

Felis bengalensis

Leopard cats are about the size of a domestic cat, but more slender with longer legs and welldefined webs between the toes. Their small head is marked with two prominent dark stripes, their short and narrow muzzle white. There are two dark stripes running from the eyes to the ears, and smaller white streaks running from the eyes to the nose. The backs of their moderately long and rounded ears are black with a central white spot. Body and limbs are marked with black spots of varying size and color, and along the back are two to four rows of elongated spots. The tail is about half the size of their head-body-length and spotted with a few indistinct rings near the black tip. There is no fixed breeding period in the southern part of its range; in the colder northern range they tend to breed around March or April, when the weather is mild enough to support newborn kittens. The estrus period lasts for 5–9 days. If the kittens do not survive, the female may come into heat again and have another litter that year. After a gestation period of 60–70 days, two to four kittens are born in a den, where they remain until they are a month old. The kittens weigh about 75 to 130 grams at birth and usually double their weight by age of two weeks; at five weeks, they are four times their birth weight. The eyes open at ten days, and the kittens start to eat solid food at 23 days. At the age of four weeks, the permanent canines appear, and the kittens begin to eat solid food. Leopard cats have lived for up to thirteen years in captivity. Leopard cats usually pair for life and raise their kittens together for about 7 to 10 months. Full maturity is reached at 18 months, but in captivity, the male can become ready to breed at 7 months, and the female at 10 months.

9. Black buck Kingdom Phylum Class Scientific name Lifespan Color

: : : : : :

Body structure

:

Height Weight

: :


Antilope capra 15 years Male: Light black color, Female: Light yellow Like deer, male has pointed horn 0.8 to 0.9 m 37 to 40 kg Components of Environment 68

Special characteristics Distribution

: :

Found in open grassland of Terai region Khairapur of Bardiya district

The blackbuck (Antilope cervicapra) is an antelope species native to the Indian Subcontinent that has been classified as endangered by IUCN since 2003, as the blackbuck range has decreased sharply during the 20th century. Males and females have distinctive coloration. Male blackbucks are dark brown, black, and white and have long, twisted horns, while females are fawn-coloured with no horns. Blackbucks originally ranged over large tracts of India except in the northeast of Nepal, the last surviving population of blackbuck is found in the Blackbuck Conservation Area south of the Bardia National Park. In 2008, the population was estimated at 184. Blackbucks generally live on open plains in herds of 15 to 20 animals with one dominant male. They are very fast. Speeds of more than 80 km/h (50 mph) have been recorded. Their chief predator was the now extinct Indian cheetah. They are now sometimes preyed upon by wolves and feral dogs. The diet of the blackbuck consists mostly of grasses, although it will eat pods, flowers and fruits to supplement its diet. The maximum life span recorded is 16 years and the average is 12 years. The main threats to the species are poaching, predation, habitat destruction; overgrazing, diseases, and inbreeding and sanctuary visitors. The incubation period of the black buck is 180 days. It gives birth to one to two young ones. Its average life is 15 years. 10. Grey Wolf Kingdom Phylum Class

: : :


Scientific name

:

Canis lupus

Lifespan Color Height Weight Body structure Special characteristics

: : : : : :

12 to 15 years Reddish brown 0.7 to 0.8 m 18 to 80 kg Long tail, large head, strong teeth Feeds on small mammals and mouse and birds

The gray wolf (Canis lupus) is a species of canid native to the wilderness and remote areas of North America, Eurasia, and North Africa. It is the largest member of its family, with males averaging 95–100 lbs., and females 80–85 lbs. It is similar in general appearance and proportions to a German shepherd, or sled dog, but has a larger head, narrower chest, longer legs, and straighter tail and bigger paws. Its winter fur is long and bushy, and is usually mottled gray in color, though it can range from nearly pure white, red, or brown to black. Wolves are equally at homes on prairies, in forest lands, and on all but the highest mountains. In Nepal, they are conserved in Makalu Barun National Park and Conservation Area, Sagarmatha National Park and Shey Phoksundo National Park. In winter, they travel in groups searching for food. Small animals and birds are the common prey of wolves, but a group sometimes attacks reindeer, caribou, sheep, and other large mammals, usually selecting weak, old or very young animals for easier capture. When no live prey can be found, wolves feed on carrion (decaying flesh of dead animals). They also eat berries. The incubation period of the wolf is 60 days. It gives birth to three to nine young ones. Its average life is 12 to 15 years. The decreasing number of wolves is the result of encroachments on their territory by humans, who have long regarded wolves as competitors for prey and are dangerous to livestock, pets, and people. Components of Environment 69

11. Gharial Kingdom Phylum Class Lifespan Color Weight

: : : : : :

Scientific name

:

Body structure Special characteristics Habitat

: Pointed part in front of nose : Feeds on only fish : Rivers in Chitwan and Bardia

Animalia Chordata Reptilia 50 to 60 years Yellowish green 50 to 70 kg

Gavialis gangeticus

Gharial (Gavialis gangeticus) is a crocodilian of the family Gavialidae that is native to the Indian subcontinent and also called gavial and fish-eating crocodile. As do all large crocodilians, the Gharial starts out life fairly small. In Nepal, small populations are present and slowly recovering in tributaries of the Ganges, such as the Narayani-Rapti river system in Chitwan National Park and the Karnali-Babai river system in Bardia National Park. Young gharials eat insects, larvae, and small frogs. Mature adults feed almost solely on fish, although some individuals have been known to scavenge dead animals. Their snout morphology is ideally suited for preying on fish. Their long, narrow snouts offer very little resistance to water in swiping motions to snap up fish in the water. Their numerous needle-like teeth are ideal for holding on to struggling, slippery fish. Gharials will often use their body to corral fish against the bank where they can be more easily snapped up. The mating season is during November through December and well into January. Between 30 and 50 eggs are deposited into the hole that the female digs up before it is covered over carefully. After about 90 days, the juveniles emerge, although there is no record of the female assisting the juveniles into the water after they hatch (probably because their jaws are not suited for carrying the young due to the needle like teeth). However, the mother does protect the young in the water for a few days until they learn to fend for themselves. Gharial is a rare species found in Nepal. An adult gharial can push itself forward and side on its belly. Its elongation, narrow snout becomes proportionally shorter and thicker as animal ages. Males utilize the structure to modify and amplify hisses snorted through the underlying nostrils. The resultant sound can be heard for nearly a kilometer on a still day. It acts as a visual lure for attracting females, and is also used to making bubbles, which have been associated with the mating rituals of the species. 12. Salak Scientific name Lifespan Color Body Structure Length Special characteristic Distribution

:

Manis spp

: 4 years : light brown : upper part of the body is covered with scales : 0.7 to 1.5 M : Feeds on insects, ants : Mid hill, Makalu Barun & Chitwan Nationla Park Kathmandu Valley


Ant- eaters eat ants termites and soft bodies grubs. Using the long, sharp claws on their forelimbs, they open insect colonies and tree trunks. They then use tongue to collect the eggs, larvae, and adult insects. The salivary glands secrete strictly saliva during feeding that coats the tongue. They only stay at one ant colony for a short period of time to avoid soldier ants, but giant anteaters can consume a few thousand insects in minutes. The tongue is attached to the sternum and moves very quickly. Flicking 150 times per minute. They will eat fruit and birds eggs on occasion. 13.Red –Crowned roofed turtle (Batagurkachuga) Kingdom : Animalia Phylum : Chordata Class : Reptilia Scientific name : Kachuga kachuga Habitat : Flowing Rivers and Lakes Distribution : Nepal (Narayani and Karnali rivers) Size : Carapace length in male 300 and female 500 mm The red-crowned roofed turtle (Batagurkachuga) is a species of turtle found in South Asia. It was the type species of its former genus Kachuga. The head is moderate size with an obtuse and moderately prominent snout. The jaws have denticulate edges with the upper not notched mesially. This reptile was historically widespread in Central Nepal, NE India, Bangladesh, primarily in deep flowing freshwater rivers with terrestrial nest sites in the watershed of the Ganges River and probably NW Burma. The diet of red-crowned roofed turtles consists entirely of water plants. They leave the water to thermo regulate by basking in the sun on rocks, logs, and sandbanks. Adult females lay eggs in March and April. The eggs are 64-75mm (2½-3 inches) long by 3846 mm (1½-1¾ in) wide. Clutch size varies from 11 to 30 eggs. The turtles are probably the most threatened freshwater turtles. Their populations have now been drastically reduced due to poaching for their meat and shells, accidental drowning in fishing gear, water pollution, hydroelectric infrastructure projects, habitat destruction by sand mining and egg predation by jackals.

6.5 Causes of extinction of animals A species becomes extinct when the last existing member dies. Extinction therefore becomes a certainty when there are no surviving individuals that are able to reproduce and create a new generation. A species may become functionally extinct when only a handful of individuals survive, which cannot reproduce due to poor health, age, sparse distribution over a large range, a lack of individuals of both sexes (in sexually reproducing species), or other reasons. In ecology, extinction is often used informally to refer to local extinction, in which a species ceases to exist in the chosen area of study, but still exists elsewhere. This phenomenon is also known as extirpation. Local extinctions may be followed by a replacement of the species taken from other locations; wolf reintroduction is an example of this. Species which are not extinct are termed extant. Those that are extant but threatened by extinction are referred to as threatened or endangered species. Causes of Disappearance of Animals There are several causes for disappearing of animals. However, some main causes are as follows: 1. Natural causes: a) Natural Disaster Natural disasters such as storm, flood, earthquake, volcanic eruption, etc. destroy the natural environment, thus destroying animals’ habitat and their food habits. This affects the living things adversely. b) Scarcity of Food


The sources of food for animals are forest, agricultural land and water resources. The scarcity of food forces birds and other animals to migrate. This may also result the extinction of some species. c)

Habitat Loss and Fragmentation Habitat loss is widely considered to be the most important cause of animal extinction. There is no doubt that habitat loss and fragmentation are the main contributors to animal extinction and animal endangerment.

d)

National and International Wildlife Trade Poaching and (legal and illegal) wildlife trade is another common threat to animals.

e)

Climate Change / Global Warming It has been recently suggested that warmer global temperatures may be affecting animals in different ways. In fact, global warming is predicted to put at least 20-30% of plant and animals species at risk of extinction, and up to 40-70% in worst-case scenarios.

f)

Introduced (invasive) Species Invasive species introduced to biodiversity rich areas damage habitats of native species and destroy their safe existence. During the 20th century, goats introduced to the Galapagas Islands fed on the tortoises, and pigs, dogs and rats ate tortoise eggs. As a result, tortoise numbers went dramatically down.

g)

Farmer / Rancher Shootings Ranchers may shoot wild animals on spot when they feel that they attack domestic sheep and thus destroy ranchers’ livelihoods. The exploitation of natural resources that often leads to animal extinction is closely linked to economic progress of the countries where this process occurs.

2.

Manmade cause of extinction for endangered animals

Man is causing the extinction of endangered animals all over the world. It is estimated that the man-made destruction of the South American rain forests is causing the extinction of approximately 27,000 species each year. This number includes bacteria and micro-organisms as well as larger animals. Human being disturbs the natural environment directly or indirectly. In order to maintain the need of growing human population, the forest is destroyed and the land is used as agricultural land. Buildings have been constructed on the agricultural land. Similarly, other developing activities of humans are increasing the pressure on forest. Due to this, the dense forests are converted to very sparse forests and are converted to dry lands. In this way, the habitat of the animals and birds are degrading. This ultimately causes the population of birds and other animals to become extinct. Such as: a)

Loss of Habitat The habitat has an important role to maintain the quality and quantity of animals and birds. The natural habitat is destroyed due to the human activities such as construction works, extension of agricultural works, excessive use of chemicals, deforestation etc. This damages the habitat, food cycle, climate, and reproductive system of creatures, etc. and there also occurs a competition among animals for food and habitat. As a result, the number of vegetation, birds and other animals goes on diminishing. If such processes continue, some of the creatures will vanish and it will affect the life of the people as well.

b)

Hunting Components of Environment 72

Hunting can be used to control wild animal populations that occur in areas developed by humans. But illegal hunting and poaching threatens wild animal populations, and often goes after species that are already endangered. For example, whaling is supposed to be regulated by the International Whaling Commission. But, according to the World Wildlife Foundation’s website, approximately 1,000 whales are killed illegally every year.

3.

c)

Man-made Migration Man-made migration happens when people introduce an animal to a foreign environment. This may not destroys the species being introduced, but it can destroy the native species. For example, if an aggressive species of fish is bought to a foreign environment, then it can start to feed on smaller native fish to the point where the smaller fish go extinct.

d)

Expansion As humans develop more land for their own use, they are destroying the habitat of the animals that used to live there. Persistent expansion of human civilization destroys the home and food sources for the native animals. If the animals are unable to adopt, then the entire species will go extinct.

e)

Pollution Man-made pollution can destroy animal species in the air, water and on the ground. Smoke stacks and car exhaust fumes that are poured into the air can contaminate entire species of birds until they are extinct. The pollution on small lakes, ponds and rivers can eliminate species of fish, and the land animals that rely on the water and fish for their survival would go extinct as well. Lack of Conservation Programme

The biodiversity conservation programme has been conducted at national, local, community and individuals levels. The establishment of national parks and conservation areas is a step to conserve the biodiversity. However, such programmes are quite limited. Various organizations should also be encouraged in this regard. The biodiversity conservation programme could be conducted in an effective way with the coordination of all sectors. 4.

Lack of Awareness

People should understand the importance of animals. The awareness programme should be conducted through formal as well as non-formal education. The increasing level of understanding of the importance of the biodiversity conservation helps the conservation of animals.

6.5 Ways of conserving animals and Plants Birds and animals are the important parts of biological system. The major conservation measures of them are discussed below: a)

Establishment of national park and reserves

A national park is a reserve of natural or semi-natural land, declared or owned by a government that is restricted from most development and is set aside for human recreation and environmental protection. Wildlife reserve is an area of land that is protected and managed in order to preserve a particular type of habitat and its flora and fauna which are often rare or endangered. These protected areas greatly contribute to conserve biodiversity. National parks  Chitwan National Park – 932 km2  Sagarmatha National Park – 1,148 km2  Langtang National Park – 1,710 km2 Components of Environment 73

 Rara National Park – 106 km2  Khapptad National Park – 225 km2  Shey Phoksundo National Park – 3,555 km2  Bardiya National Park – 968 km2  Makalu Barun National Park – 1,500 km2  Shivapuri Nagarjun National Park – 159 km2  Banke National Park – 550 km2 Wildlife reserves  Koshi Tappu Wildlife Reserve – 175 km2  Parsa Wildlife Reserve – 499 km2  Sukla Phanta Wildlife Reserve – 305 km2 Conservation areas  Annapurna Conservation Area – 7,629 km2  Manaslu Conservation Area – 1,663 km2  Kanchenjunga Conservation Area – 2,035 km2 Hunting Reserve  Dhorpatan Hunting Reserve – 1,3255 km2 Ramsar Sites  Bess hagari Tal – 3,200 ha  Ghodaghodi Tal – 2,563 ha  Jagdishpur Reservoir – 225 ha b)

Conservation of natural habitat

Habitat conservation is a land management practice that seeks to conserve, protect and restore, habitat areas for wild plants and animals, especially conservation reliant species, and prevent their extinction, fragmentation or reduction in range. It is a priority of many groups that cannot be easily characterized in terms of any one ideology. c)

Ex-situ conservation

It is the process of protecting an endangered species of plant or animals outside of its natural habitat; for example, by removing part of the population from a threatened habitat and placing it in a new location, which may be a wild area or within the care of humans. d)

Protection of forest

Forest protection is a general term describing methods purported to preserve or improve a forest threatened or affected by abuse. The types of abuse that forest protections seeks to prevent include:  

Aggressive or unsustainable farming and logging. Expanding city development caused by population explosion and the resulting urban sprawl

As forest is the habitat for large number of different animals and birds, protection of forest contributes to conserve the animals and birds. e)

Human-made Conservation Site (Zoo) The conservation of all kinds of organisms cannot be made in in-situ. The organisms will vanish if suitable natural environment is not given to them. So, people have to create artificial natural environment to conserve the organisms which are rare and which are likely to vanish. The conservation of the creatures made in such a way is called ex-situ conservation. Thus, besides the insitu conservation of organisms, the efforts of conservation at other suitable places are also going on. It is called ex-situ conservation. Components of Environment 74

Gardens and zoos are constructed for the conservation of rare and vanishing vegetation, animals and birds. In the Central Zoo in Jawalakhel of Latitpur district, efforts have been made for conserving birds and animals by creating suitable natural environment. Similarly, a botanical Garden is also established for conserving different kinds of plants and trees. Such conservation works help in conserving biodiversity to great extent. These conservational works also help in protecting the breed of living beings. More conservation measures a) Preserve important breeding sites, especially sensitive habitat, such as wetlands, and colonial nesting sites. b) Preserve critical migratory stop-over sites, especially important wetlands, riparian zones, and open grasslands with high quality forage. c) Reduce habitat loss and fragmentation through planning, good management practices, and acquisition. d) Reduce habitat degradation in sensitive areas, especially by reducing pesticide use, human disturbance, and invasion by destructive species, and incompatible land uses. e) Increase the amount of habitat available through ecological restoration, creation, and enhancement. f) Educate the public about the importance of birds and the need to protect and restore their habitat. g) Work cooperatively with the public and other nations to understand the threats to species and reverse negative effects. h) Support research and monitoring that provides information on the status of species, threats, and potential conservation approaches for reducing threats.

6.5 Wild Animal Conservation in Nepal Recognition of the importance of biological diversity in Nepal dates back about 170 years when Jung Bahadur Rana (during 1840s) placed restriction on the hunting of certain animals. The central zoo was also established during that period. However, the purposeful and active efforts towards the conservation of biodiversity started some 30 years ago. During this period, Nepal join the community in recognizing the global importance of biodiversity and become the partner to a number of international conventions and other agreements to protection and management, and a lot has yet to be done based on the past experience. The importance of conserving wild species of flora and funa in Nepal was first recognized in its Five Year Development Plan (1956-1961) with the establishment of ‘Rhino Patrol’ in 1961, which provide successful in controlling the protection of biodiversity, great dependence is placed on the protected areas system of Nepal. Protected areas (Pas) were initially established in Nepal for the protection of wildlife. However, the objectives have now been broadened to include the preservation of natural, historic, scenic and cultural values. According to the latest estimates, 26,695 km2 (18.32%) of the total area of Nepal, is now declared protected. The National Parks and Wildlife Conservation Act, 1973 provides the legal basis for the management of Pas. The act was later on amended four times in 1974, 1982, 1989 and 1994 and recognizes following six categories of Pas in Nepal. 1.

National Parks The NPWC Act defines a national park as an area set aside for the conservation and management of the natural environment, including ecological, biological and geomorphologic associations of aesthetic importance. To develop the area for eco-tourism is the second objective, provided that it copes with sustainable conservation.

2.

Strict Nature Reserve Components of Environment 75

This is an area of unusual ecological or other significance set-aside for the purpose of scientific study. The inaccessible lower Barun valley, fed by the Salimad River, a glacier-fed tributary of the Arun River, is the most pristine area in the Makalu Barun National Park, and thus has been designated as a strictly first Nature Reserve in Nepal. 3.

Wildlife Reserve A wildlife reserve is an area established for the conservation and management of plants and wildlife and their habitat.

4.

Hunting Reserve It is an area set-aside for the conservation and management of wildlife to provide opportunities for legal recreational hunting.

5.

Conservation Areas This type of protected areas is managed according to an integrated plan for the conservation of the natural environment and the sustainable use of the natural resources contained within it.

6.

Buffer Zone It is the designed area surrounding a national park or a reserve within which the use of forest products by local people is regulated to ensure sustainability.

EXERCISE A.

B.

C.

D.

Very short questions 1) What are indigenous species? Give example. 2) State any two indigenous animals of hilly region. 3) State any two indigenous animals of terai region. 4) Define endangered species? Give example. 5) State scientific name of one horned rhino. 7) State in which part of Nepal Gaur animal is found. Short answer type questions: 1) What are indigenous species? State different indigenous plants and animals of Nepal. 2) Explain the importance of indigenous species of Nepal. 3) What are endangered species? State different causes of extinction of animals and plants from the earth. 4) Write short notes on a) tiger b) One –horned Rhino c) Music deer d) Show-leopard e) Black buck f) Ghanial g) Danfe. Long answer types question 1) What are indigenous species? State two - two indigenous plants and animals of Nepal according to the ecological belt. Also explain the importance of indigenous animals. 2) What are endangered species? Sate different causes of the extinction of the indigenous species and also describe the methods of conservation of the indigenous species. Practical problems 1) Write a report on the conservation of indigenous species of Nepal. 2) Visit a nearby national park and make a report on the different types of the plants and animals found there.




UNIT Energy 7.1

Energy

7.1.1 Introduction Energy is the capacity of a physical system to perform work. Energy exists in different forms like mechanical energy, thermal energy, chemical energy, electrical energy, radiant energy and atomic energy. The total energy contained in an object is identified with its mass, and energy cannot be created or destroyed. When matter (ordinary material particles) is changed into energy (such as energy of motion, or into radiation), the mass of the system does not change through the transformation process. However, there may be mechanistic limits as to how much of the Matter in an object may be changed into other types of energy and thus into work, on other systems. Energy, like mass, is a scalar physical quantity. In the International System of Units (SI), energy is measured in joules. Units of Heat As a form of energy, the SI unit for heat is the joule (J), but in many fields other units, such as kilowatt-hours and kilocalories, ergs etc. are customary. All of these units translate to units of work, which is always defined in terms of forces and the distances that the forces act through. Heat is frequently also measured in the calorie (cal), which is defined as "the amount of heat required raising the temperature of one gram of water from 14.5 degrees Celsius to 15.5 degrees Celsius." Heat is also sometimes measured in "British thermal units" or Btu. The British thermal unit (symbol Btu or sometimes BTU) is a traditional unit of energy equal to about 1.055 KJoules. A Btu is defined as amount of heat required to raise the temperature of one 1 pound (0.454 kg) of liquid water by 1 °F (0.556 °C) at a constant pressure of one atmosphere. 7.1.2 Importance of the energy All life on earth depends in some way upon energy. Most of the earth energy comes from the sun. It travels to the earth in rays or waves. Energy in this form is used by plants to make food. Plant food is needed to sustain life by providing nourishment for our bodies and muscles. The sun's energy is also stored in coal, wood and oil which are also used to produce food and modify matter. Importance of the energy can be explained on the following points: 1.

Heating and lighting purpose: The uses of energy in the form of heat and light can be explained as: (a) Heat Heat energy is another form of energy that is used to heat our homes. Many times this heat energy can be used more efficiently. In some cases, this heat can be used to create more energy. (b) Light Light energy affects eater temperature, biological and plant photosynthesis and growth. Under natural conditions, topography, cloudiness, vegetation cover, and seasonal patterns, like less daylight in winter, control light.

2.

Fuel Fuel is the substance that burns and gives out heat energy. The term “fuel” is the generally limited to those substances that burns readily in air or oxygen emitting heat energy. Some examples of Components of Environment 79

fuel are wood, coal, petroleum etc. In our daily life we use various source of heat energy. In most of rural areas, the people mostly used firewood, agriculture residues, animal dung etc. as sources of energy whereas few people use biogas also. In urban areas people use electricity, coal, gas, petroleum fuels etc., as the main source of energy. The electricity, petrol, diesel, coal and other have been used as fuel for transportation. Similarly, electricity, diesel, coal, rice husk etc. have been used as fuel for industries. The combustion of all ordinary fuels involves the chemical reaction of oxygen with carbon, hydrogen, or sulfur dioxide. Other substances present in fuels are either driven off in the form of vapour or remain in the form of ash after combustion. These days there has been remarkable development of industrial sector as well as transportation sector. There is definitely vital role of energy in the development of these sectors. Fuel is used for domestic and large scale purposes. Following are some areas where the fuels are used in large scale. Industry Generally industry means the production of goods and / or services. Beverage industry, gold industry, textile industry, steel industries, music industry, dairy, sugar mill are some examples of goods producing industry. Some industry produce physical goods, such as lumber,, steel, or textiles. Other industries like airlines, railways, and other transport industries provide services by transporting people or goods from one place to another. Similarly banking and restaurant industries provide financial services and food services respectively. Energy is needed for operating an industry. Based on the nature of industries, some need more energy and some need less energy. The widely used sources of energy are electrical energy and thermal energy. (i)

(ii)

Transportation Transportation provides access to natural resources and contributes the trade promotion. Transportation system and the routes greatly influence the human population. Reliable transportation allows a population to expand throughout the country’s territory and live comfortably in remote areas far from factories and farms. In order to operate the transportation we need petroleum fuels e.g. diesel, petrol, mobil, etc. The petroleum, fuels burn and produce heat energy. In the later 20th century, people become more aware of the effects of transportation system on the environment. For examples, the burning of petroleum fuels in vehicles gives rise to pollution. Other effects of transportation system on environment include impacts on noise levels, water quality, hazardous materials, natural habitats, and wetlands. Fig : Vehicles in Kathmandu valley using fuel The importance of energy in our daily life From the time we wake up to the time we go to sleep at night, energy has affected our life. Energy is important in everyone’s life, whether we notice it or not. Without it we would have a harder time waking up and an even harder time getting anywhere. Energy is important whether its solar energy, mechanical energy, nuclear power, or the energy our body makes that allows us to talk, move, and walk. These are the tasks that we normally do that involve energy, and that we could not do without it.


Energy is important to heat our homes, and most houses have gas, oil or electric heaters. The mechanical energy in a wind up alarm or electric energy in a battery or plug in alarm is important to wake us up. Energy is needed to heat water, which is used when we take a shower or wash our face in the morning. Just imagine washing our face or taking a shower with ice-cold water in the winter. It would be bad. If we brush our teeth with an electric toothbrush, then energy allows our teeth to be clean. Energy even affects when we put on fresh clothes in the morning. Our clothing is probably made in a factory, which is powered by electricity. Now imagine ourselves in a class when someone’s cell phone starts ringing. Energy causes these persons to get in trouble. However, the battery on our cell phone also helps us communicate with people. Next, we go to school, which involves energy getting there. If we get a ride to school in either a school bus or a car, gasoline is used to power the car. We probably pass a traffic light on our way to school and that is powered by electricity. Without energy, cars would be going all over the place and crashing all the time. A traffic light helps to manage the chaos. If we walk to school, we use the energy our body makes from converting calories from food to energy. We may also turn on TV, and energy is needed to bring breaking news to us. It brings pictures and sound to us from the television. All life on earth depends in some way upon energy. Most of the earth energy comes from the sun. It travels to the earth in rays or waves. Plants to make food use energy in this form. Plant food is needed to sustain life by providing nourishment for our bodies and muscles. The sun’s energy is also stored in coal, wood and oil, which is also used to produce food and modify matter. It has been estimated that the amount of energy falling on the earth surface annually is equal to the energy of 250 million tons of coal.

7.2

Sources of energy

We get energy from different sources. A source of energy is the substance which can provide enough useful energy at a steady rate over a long time. A good source of energy has following properties. (a) It is safe and convenient to use. (b) It is ready to store. (c) It is ready to transport. These sources of energy can be categorized into two main types. 1.

Renewable energy sources: Renewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable (naturally replenished). About 16% of global final energy consumption comes from renewable, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from hydroelectricity. These are mostly biomass-based and available in unlimited amounts in nature since these can be renewed over relatively short period of time. These can reproduce themselves in nature and can be produced continuously through a sustained proper planning and management. Main Renewable energy sources are: (a) Biomass energy (b) Solar energy (c) Hydro energy (d) Geothermal energy

a.

Solar Energy Solar energy is produced by nuclear fusion reactions deep in the sun’s core. Solar energy reaches the earth through space in discrete packets of energy called photons. On the side of earth facing the sun, a square kilometer at the outer edge of our atmosphere receives 1,400 megawatts of solar power energy every minute, however only half of the amount, reaches the earth’s surface and the Components of Environment 81

other half is observed or scattered by atmosphere and clouds. The intensity of sunlight that reaches any particular point on the earth’s surface depends on the time of the day, the day of the year, the amount of cloud cover, and the latitude at the point. Solar-generated thermal energy concentrates radiation to a single point using mirrors to produce solar furnace, which has a temperature range up to 3000 oC. This furnace is used for melting of rare metal. Simple versions of solar heaters are also used for cooking. Plants convert solar energy to the chemical energy through photosynthesis. People use such stored solar through fuels like wood, alcohol, and methane that are extracted from the plant biomass. Fossil fuel such as oil and coal are derived from geologically ancient plant life. Animals that feed on plants obtain energy from plant bodies. Solar energy can be obtained continuously. Developing solar power stations, we can store solar energy and use it for various purposes. The devices, which convert solar energy into other forms of energy, are called solar devices. The following are the solar devices that are being used so far. (a) Solar heater (b) Solar cells (c) Solar cooker (d) solar power plants (e) Solar furnace The solar cells are the devices, which converts solar energy directly into electrical energy. A group of cells joined in a particular way is called solar panel. The solar cell produces any quality of electrical energy. It is used in artificial satellites, operating communication devices in the remote areas, operating water pumps etc. In Nepal, the solar cell is being popular for lighting house and running TV, computer etc. in remote areas. Fig: Solar panel Advantages of Solar Energy a) The use of solar energy does not cause any environmental pollution. b) It is the cost free perpetual source of energy. c) It is multi-purpose energy source Limitation of Solar Energy a) It is not available uniformly all the time and all the places. b) It is not available during night, rainy day, cloudy day etc. c) It reaches the earth in diffused form, which is not sufficient enough to generate large amount of energy. b.

Wind energy Wind energy is the energy contained in the force of the winds blowing across the earth’s surface. The differential heating of the earth surface by the sun cause wind. When harnessed, wind energy can be converted into mechanical energy, which could be used for various purposes such as pumping water, grinding grain, milling lumber, etc. By connecting a spinning rotor to an electric generator, modern wind turbines convert wind energy into electrical energy. Our country has also a good potential for windmill electricity in Jumla, Dolpa and Mustang. A 20 Kilo Watt wind energy plant has already been established at Kagbeni, Mustang. Since wind is the clean and renewable source of energy, modern wind turbines are being installed in countries such as Germany, Denmark, India, China, and the United States to supplement more traditional sources of electric power. Components of Environment 82

Advantages of Wind Energy a) It provides energy without depleting the environment. b) It is the cost free perpetual source of energy. c) It can use to operate water-lifting pumps, flourmills and to generate electricity. d) It can be used to propel sailboats. Disadvantages of Wind Energy a) It cannot produce large amount of energy. b) It is not as reliable as hydropower energy. c) It is useless in the areas where strong wind doesn’t blow. c.

Hydroelectricity Water flows towards lower level due to the gravitational force. The flowing water possesses mechanical energy. Mechanical energy of water is used to generate the electrical energy, which is known as hydro-electricity. There are thousands of rivers in our country. They are important resources. Traditionally, water resources have been used for running water mills (ghatta). In modern times electricity is generated from water resources. We can still generate enormous of electricity from our water resources. It has been estimated that we have the potential of generating about 83,000 MW of electrical energy in Nepal but there has been production of about 600 MW of electrical energy only. Electricity produced by falling water is called hydroelectricity. Hydropower supplies more than one fifth of the world’s total electricity, and several countries depend upon hydropower for electricity, such as Brazil (80%), Spain (50%), Italy (40%), Japan (23%) and Canada (16%). Although the production cost for the generation of hydroelectricity is high in the beginning, it is cheaper on long term use. Advantages of Hydropower Energy a) Although the production cost is high, it is cheaper in long term basis. b) It supplies energy without pollution. c) It is a renewable source of energy. d) It is easy to transform to other form of energy. Very small to very high power can be generated as perFig: need. Kaligandaki hydropower Project e) Very small to very high power can be generated as per need. f) It is the only major source of energy for computers, modern electronic devices and means of communication. Disadvantages of Hydroelectric Energy a) The fatal electric shock can take the lives of people and animals. b) The construction of large dams may submerge large area of fertile land. c) The natural flow of water in the water source is affected. Hence, it affects the aquatic lives. d) Settlements of large numbers of families can be affected. Since the construction of power plant needs large area, the settlement of people has to be shifted to other places. e) Running of vehicles by electricity is not convenient. d.

Biomass Energy The energy that can be obtained from biomass like agriculture residue, animal waste, wood, weeds etc. is called biomass energy. Hay, straw, stalks of jute and maize, husk, saw dust, firewood, animal dung etc. are some sources of biomass energy. These fuels can be used instead of coal. In rural areas of Nepal, the dung of cattle is given cylindrical shape and sun-dried to make fuel. It is known as Guintho. Similarly, Briquet Koila (artificial coal) is made by using Banmarajhar, (a kind of Components of Environment 83

useless weed), other weeds and sticky black clay. Briquet Koila is used to have mild heat during winter season. It is also used in cooking. Bio-fuel is any solid, liquid, or gaseous fuel produced from organic matter. Bio-fuel is produced either directly from plants or indirectly from industrial, domestic, or agricultural wastes. There are three main methods for the development of bio-fuels: the burning of dry organic wastes (such as household refuse, industrial and agricultural wastes, straw, wood, and peat); the fermentation of wet waste (such as animal dung) in the absence of oxygen to produce biogas; or the fermentation of sugarcane or corn to produce alcohol and esters; and energy forestry. Advantages of Biomass Energy a) It is cheapest source of energy. b) It is available in local level very easily. c) It is a renewable source of energy.

Fig : Biomass Sources

Disadvantages of Biomass Energy a) It causes air pollution by releasing a lot of smoke. b) It is inconvenient to produce large amount of energy at a time. c) It cannot be used as a fuel of vehicles. e.

Geothermal Energy The inner part of the earth is extremely hot. It is obvious that at the time of volcanic eruption or earthquake, the magma (lava) and other gasses rush out explosively at high temperature. On the average, the temperature rises by 30 per kilometer but by 80 per kilometer in volcanic and earthquake regions. By drilling a hole, if water is allowed to contact to such hot regions, it instantly gets converted into steam. Such generated steam comes out from the hole forcible and rotates the turbine of generator to produces electricity. The energy obtained in such a way is called geothermal energy. Hot springs are also the form of geothermal energy. There are also a number of hot spring in Nepal, Example Dolpa, Humla, Fig : Steam rising from the Nejavellrr Myagdi, Baglung, Dailekh, Gorkha, Bajhang, Geothermal Power Station in Iceland Dhading, Barhabise, etc.

Advantages of Geothermal Energy  Geothermal energy generally involves low running costs since it saves 80% costs over fossil fuels and no fuel is used to generate the power. Since, no fuel is require so costs for purchasing, transporting and cleaning up plants is quite low.  It does not create any pollution and help in creating clean environment. Being the renewable source of energy, geothermal energy has helped in reducing global warming and pollution.  Governments of various countries are investing hugely in creation of geothermal energy which on other hand has created more jobs for the local people.


Disadvantages of Geothermal Energy  Since this type of energy is not widely used therefore the unavailability of equipment, staff, infrastructure, and training pose hindrance to the installation of geothermal plants across the globe.  To get geothermal energy, requires installation of power plants, to get steam from deep within the earth and this require huge one time investment and require hiring a certified installer and skilled staff needs to be recruited and relocated to plant location. Moreover, electricity towers, stations need to set up to move the power from geothermal plant to consumer.  Geothermal sites may contain some poisonous gases and they can escape deep within the earth, through the holes drilled by the constructors. The geothermal plant must therefore be capable enough to contain these harmful and toxic gases. 2.

Non renewable Energy Sources A non-renewable resource is a natural resource which cannot be produced, grown, generated, or used on a scale which can sustain its consumption rate, once used there is no more remaining. These resources often exist in a fixed amount and are consumed much faster than nature can create them. Fossil fuels and nuclear power are examples. In contrast, resources such as timber or metals are considered renewable resources. a.

Fossil Fuel A chemical substance that burns in air to produce heat energy or produces heat due to nuclear processes is called fuel. The fuel can be categorized as fossil fuel, nuclear fuel etc. The fuel which has been obtained from the dead remains of plants and animals of millions of years ago is called fossil fuel. Coal, petroleum etc are the fossil fuels. (i)

Natural Gas Natural gas is a flammable gaseous mixture consisting mostly of hydrocarbons. Along with coal and petroleum, natural gas is a fossil fuel. It may contain about 85 percent methane (CH 4) and about 10 percent ethane (C2H6). Methane is found in underground rock layers as well as above natural deposits of petroleum. Natural gas is the least abundant fuel. It is extracted and refined into fuels that provide approximately 25 percent of the world energy supply. Natural gas is used both as fuel and as a raw material in the manufacturing of chemicals. As a domestic fuel, it is burned in furnaces, water heaters, cooking stoves, and clothes dryers. As an industrial fuel, it is burned in kilns used to bake bricks and ceramic tiles and to produce cement. Natural gas is also used for generating steam in water boilers and as a source of heat in making glass and in processing food. Nowadays, a kind of gas called liquefied petroleum gas (LPG) is prepared artificially from crude oil. This gas is used for cooking, heating, transportation, machinery uses, etc.

(ii)

Mineral Oil The purified residue of petroleum obtained in the form of a yellowish or decolorized semisolid is known as petroleum jelly, and the one obtained in the form of a clear to faintly yellow liquid is known as mineral oil. The mineral oil consists of petrol, diesel, mobil, kerosene etc. The formation of natural gas is the indicator of forming petrol. As a result of various geological processes, plants and animals were dumped and decayed. After a long time, minerals oil is formed from their remains due to heat and pressure inside the earth. The mineral oil is found in the layers of rocks. The well of the oil is generally found at the depth of 1000m to 2000m. Such wells also contain water below the layer of oil. The oil is drawn from the well with the help of pump. Such oil is called crude oil. The refining of crude oil results into petrol, diesel, kerosene, mobil etc. The waste produced during this process is called coal tar. Components of Environment 85

Mineral oil is the source of heat and light. Machineries used in the industries also need lubricants. Various means of transportation such as bus, car, tractor, train, ship, aero plane, etc., also need mineral oil for the operation. Artificial rubber, polish, cosmetics, etc., are produced from mineral oil. There are big reserves of mineral oil in some countries such as the United States of America, Netherlands, Canada, Germany, Iran, Iraq, Venezuela, etc. In Nepal there is possibility of the mineral oil reserve in Mukthinath, Dailekh, Dang, Salyan, Pyuthan, Surkhet, Jhapa, Morong and Chure hills. Important uses of the mineral oil: 1. Petrol is used to run small vehicles such as motorbikes, cars etc. 2. Diesel is used to run heavy vehicles such as buses, trucks, tractor and other diesel engines. 3. Kerosene is used as fuel in stoves, lamps etc. 4. Pure kerosene is used as fuel in aero planes. 5. Lubricating oils is used as a lubricant in the moving parts of machine. 6. Paraffin is used in the manufacture of candles, wax, boot polish etc. (iii)

Coal Coal is a dark-colored solid fuel found in deposits of sedimentary rock. We burn coal to produce energy and use it in factories. It is also an important source of chemicals, which are used to make pharmaceuticals, fertilizers, pesticides, and other products. Coal forms from ancient plants buried over millions of years in the earth’s crust. Coal, petroleum, and natural gas are known as fossil fuels because they formed the fossils of the ancient lives buried deep in the earth. Coal is rich in hydrocarbons. All life forms contain hydrocarbons. Generally hydrocarbons containing material is called an organic material. It is already mentioned that due geological changes the ancient plants were buried under layers of sediment. More and more layers of sediment gradually continued to form over the buried plant parts. Over millions of years, excessive heat and pressure caused coal to form the carbon, hydrogen, oxygen, nitrogen, sulphur, and mineral compounds present in the plant parts. There are four types of coal. They are anthracite, bituminous, lignite and peat. Coal has been widely used as a source of heat energy. It is used at homes, factories, trains, etc. While coal burns, it produces carbon dioxide and carbon mono-oxide. These gases are harmful. In Nepal there is possibility of coal reserve in Dang district. The coal found in Nepal is of somewhat low quality, i.e. Lignite. The extraction of the coal from the coal mines and the resulting rock waste can disrupt the environment. Furthermore, burning coal released environmentally harmful chemicals compounds into the air.

The uses of coal can be summarized as follows a) It is used as fuel in metal industries like iron and steel, brick factories and cement industries. b) It is also used for cooking, heating and steam engines. c) It is essential for the manufacturing of dyes, drugs, fertilizers, plastics etc. d) It is used as the fuel of trains. Advantages of Fossil Fuel 1. It is cheaper and can be easily available. 2. It can be easily transported. 3. It is easy to store and convenient to use. 4. It is a multipurpose fuel that can be used to run different engines and vehicles. 5. It can be used for generating electricity. Components of Environment 86

Disadvantage of Fossil Fuel 1. The burning of fossil fuel produces smoke and other harmful gasses which cause air pollution. 2. These sources have limited stocks. 3. The mineral oils and highly inflammable. Hence, they can cause fire or explosions in case of mishandling. 4. Leakage of mineral oils in to the water sources causes the large damage of aquatic lives. f.

Nuclear energy The energy obtained from the building up or breaking down of a heavy nucleus is called nuclear energy. Nuclear energy is obtained from the nuclear reactions. The reactions leading to the building up or breaking down of a nucleus are called nuclear reactions. The nuclear reactions are of two types: 1. Nuclear fission The process of breaking down of heavier nucleus into smaller fragments with the release of large amount of energy is called nuclear fissions. For examples, when a slow neutron strikes the nucleus of uranium, the uranium nucleus splits into the nuclei of lighter elements and produces large amount of energy. 1 235 0n + 92U

High temp. high pressure 56

Ba141 + 36Kr92 + 30n1 + energy

Nuclear fission reaction takes place in atom bombs. 2.

Nuclear fusion The nuclear reaction in which two or more lighter nuclei fuse together to form a heavy nucleus with the release of large amount of energy is called nuclear fusion. For example, if four hydrogen nuclei are combined, they form a helium nucleus ( 2He4) and two positive (+1e0) with the release of energy. 41H1

High temp. high pressure He4 + 2 e0 + energy 2 1

Fusion reaction occurs at ultra-high frequency (about 108 K) and pressure. Since such amount of temperature can’t be found on earth’s surface, fusion reaction is not possible on the surface of the earth. Since nuclear fusion reaction is not possible in the earth surface nuclear energy is obtained from controlled nuclear fission reaction. 3.

Nuclear energy In nuclear fission, when the nucleus of the radioactive element is bombarded with free neutrons, the nucleus breaks down into new lighter nuclei. In this process some mass is lost and an immense quantity of heat energy is released from the lost mass. The heat thus produced is used to boil water into steam. The steam operates the large steam engines which run generator. Thus electricity is produced by the generator. Thousands of megawatts of electricity can be generated by this means. Advantages of Nuclear energy a) Huge amount of energy can be obtained from a small quatity of fuel. b) A single supply of fuel into nuclear power station produces energy for 2-3 years

Disadvantages a) It contaminates the environment with nuclear radiations, which are dangerous to the organisms. b) Production cost is so high that poor countries cannot afford it. c) The harmful wastes produced by nuclear fission are very difficult to manage. They cannot be stored or dumped in rivers, seas or open fields.


7.3

Conservation of the energy

Energy conservation refers to efforts made to reduce energy consumption. Energy conservation can be achieved through increased efficient energy use, in conjunction with decreased energy consumption and/or reduced consumption from conventional energy sources. An energy conservation act was passed in 2001. Energy conservation can result in increased financial capital, environmental quality, national security, personal security, and human comfort. Individuals and organizations that are direct consumers of energy choose to conserve energy to reduce energy costs and promote economic security. Industrial and commercial users can increase energy use efficiency to maximize profit. We can say that, Energy conservation means using energy in wastefully but more efficiently. Conservation of energy is an important strategy because a unit of energy saved is good as a unit of energy generated. Ways of energy conservation can be discussed as:

7.3.1 At individual efforts of energy conservation Using energy-efficient equipment: Efficiency means getting the greatest possible amount of output with the least amount of inputs resources, effort and cost. Through efficiency, we can use less energy to do the same amount of work and in some cases; we can do even some more work. For example, we may use a pressure cooker or an improved stove, energy-efficient model of refrigerator, a compact fluorescent light bulb, etc. Energy efficient models or products may initially cost more than conventional ones, but save money in long run by having the lower life cycle cost, i.e., initial cost plus lifetime operating costs. The saving in energy is one-time saving because an energy-efficient device goes on saving energy throughout its life. Energy conservation is often the cheapest, and perhaps the largest source of energy available to us. Changing energy wasting habits and lifestyles In our daily life, the switching off a light when it is not needed, walking or riding a bicycle instead of using a two-wheeler or a car for a short distance, regularly defrosting the refrigerator are some examples of energy saving habit. Similarly, turning off the tap while brushing our teeth it helps not only to save water but it also helps to save energy used for pumping the water. Such changes in habit do not cost any money. Equally important is cutting down the unnecessary consumption in our daily life. All commodities require the input of energy at all stages of production, packaging and transportation.

7.3.2 At Sectorial effort of conservation of energy 1.

Industry The largest consumer of the commercial energy in Nepal is industry. Therefore, this sector can make the greatest contribution to energy conservation by using energy saving equipment and adoption more efficient and sustainable processes and practices. Products should be designed and redesigned to use less material or substitute it with new materials, which require relatively less energy in their manufacture. Manufacturing processes should also be made more efficient. 2.

Transport After industry, this sector is the largest consumer of energy. While the entire transport system needs major restructuring to make it more efficient operationally as well as in its use of energy, the focus here is primarily on the urban commuter transport system. Vehicular traffic in cities and towns is the major source of air pollution, noise pollution, light pollution and road congestion. There is a need to develop energy-efficient motorized vehicles and systems for their proper maintenance, to ensure fuel efficiency and less pollution. Improvements in public transportation, besides reducing pollution and saving energy and money, would also reduce the dependence on private vehicles and improve the quality of transportation services available to the average citizen. Components of Environment 88

3.

Power It is the responsibility of power companies and state electricity boards to meet the electricity requirements of their customers. A concept that has great value, especially for the power sector, is demand side management. In relation to this, the power companies should help their customers to adopt the possible ways so as to reduce demands for more power instead of just trying to meet the current shortages and fulfilling increasing demands for more power. A fundamental problem with the energy sector in Nepal is the value of policy. Consumers pay for electricity much less than what it costs to produce and deliver. If consumers were to pay more realistic price, they would use commercial energy less wastefully and more carefully. A more rational energy pricing policy, combined with incentives, would therefore encourage energy conservation. 4.

Uses of solar energy Solar energy does not refer to a single technology but rather covers a diverse set of renewable energy technologies that are powered by the sun’s heat. Some solar energy technologies, such as heating solar panels, utilize sunlight directly. On the other hand, the hydroelectric energy relies on the sun’s ability to evaporate water. Similarly, the fuel from biomass depends on plants and their growth. The common feature of solar energy technologies is that, unlike oil, gas, coal, and present forms of nuclear power, solar energy is inexhaustible. Solar energy can be divided into three main groups heating and cooling applications, electricity generation, and fuels from biomass.

7.4

Conservation measure of the renewable natural resources

Conservation is achieved through measures adopted in favour of the natural resource in order to increase its longevity and improve usage patterns. Some such measures are as follows: a.

Rational use of the resources Rational use of resources is one of the concepts of the conservation of natural resources. Preservation also serves an ecological purpose by maintaining the function of the total environment. It also implies the direct use of resources for their commodity or recreational value. b.

Sustained yield Concept of sustained yield is a conservation measure. This means cropping the annual surplus of individuals so as not to endanger the breeding stock of game animals or fish. Similarly, tree cutting or grazing of grass should remove only the annual increment and no more. c.

Restoration It is a widely familiar conservation measure, which is essentially the correction of past careless activities that have impaired the productivity of the resource base. Depleted animal and plant populations can recover if they are granted protection. This measure is familiar in modern soil and water conservation practices are applied to agricultural land. Restoration is possible only as long as species are applied to agricultural land. Restoration is possible only as long as species are protected and genetic diversity of life is maintained. When species become extinct, the restoration of past conditions becomes impossible. d.

Protection Protection of natural resources is necessary from commercial exploitation to prolong their use for recreation, watershed protection, and scientific study. This is the concept underlying the establishment and protection of parks and reserves of many kinds. e.

Reutilization Reutilization is the reuse of waste materials, as in the use of industrial water after it has been purified and cooled. The same process becomes recycling if the water material requires minor treatment before it can be used, as in the use of scrap iron in steel manufacture. Components of Environment 89

f. (i) (ii)

Substitution Substitution, an important conservation measure, has two aspects: The use of a common resource instead of a rare one when it is for the same purpose. The use of a renewable rather than a non-renewable resource when conditions permit.

g.

Integration Integration in resource management is a conservation measure. This is preferable to maximize certain benefits from a single resource at the expense of other benefits or other resources. Integration is a central objective of planning. The conservation measures can be discussed under following headings:  Development of biological energy: Development of biomass energy.  Save energy from wastage: No use of energy more than needed.  Proper use of energy: Use of energy only in required amount.  Use of efficient equipment: Use of appliances having more output.  Use of solar energy: Promotion on use of alternative source of energy

7.5

Conservation Measures of Non-Renewable Natural Resources

Non-renewable natural resource is the non-renewable resource. It takes thousands of years for the formation and concentration of resource. The rate of formation is much smaller than the rate at which the humans consume it. It is necessary to reduce wastage of it. Non-renewable natural resource can be conserved in by the following measures:  Use of improved technologies to allow use of low grade resource at low costs. 

Using substitutes



Recycling of resource in good way in which the resource can be conserved. They can be used in a judicious manner. Conservation measures of non-renewable natural resources can be discussed under the following headings: 

Proper use of resource: Use of resources only in required amount.



Conservation of reserves: Preservation of the resource for the future use as far as possible.

7.6

Effects of Non-Conserving Energy in the Environment

Energy is necessary in each steps of our life. It is to conserve the existence of life. If energy is not preserved, it may results in following effects: a. Loss of the resource Non-conserving energy is simply means wastage of energy. It is obvious that natural resources are the source of energy. Once we waste the energy, we lose the natural resources. b.

Loss of biodiversity Natural resources comprise a large number and different kinds of plants. When we exploit resources, there is exploitation of natural resources. The over use of plant resource is responsible for the loss of plants and animals. It is because plant resource provides habitat for animals there is loss of animals with the loss of plants.

c.

Change in climate The more use of energy, the more the generation of GHG s such as carbon dioxide, methane, carbon monoxide, CFCs, oxide of nitrogen and so on resulting the change in atmosphere phenomenon for long period. Components of Environment 90

d.

Energy crisis The overuse or misuse of renewable and non-renewable sources of energy may bring crisis in energy. We have been using more and more forest products resulting thereby the decrease in forest area as well as the forest production. It means that the energy from forest is also decreasing. The increasing demands of coal, petrol, and gas also increase their cost. In future, it might be difficult to fulfill energy as per demand. e.

Problems of pollution In early days, the oil industry generated considerable environmental pollution. Through the years, however, under the dual influences of improved technology and more stringent regulations, it has become much cleaner. The effluents from refineries have decreased greatly and, although well blowouts stilloccur, new technology has tended to make them relatively rare. The policing of the oceans, on the other hand, are much more difficult. The ships are still a major source of oil spills. Another source of pollution connected with the oil industry is the sulfur in crude oil. Regulations of national and local governments restrict the amount of sulfur dioxide that can be discharged by factories and utilities burning fuel oil. Because the removing of sulfur is quite expensive, regulations still allow some sulfur dioxide to be discharged into the air. Many scientist believe that another potential environmental problem from refining and burning large amount of oil and other fossil fuels occurs when carbon dioxide (a by-product of refining petroleum), and other by-product gases accumulated in the atmosphere. These gases are known as greenhouse gases. This energy, trapped in form of heat, maintains the earth temperature that is hospitable to life. Certain amounts of greenhouse gases occur naturally in the atmosphere. However, the immense quantities of petroleum, coal, and other fossil fuels burned during the world’s rapid industrialization over the last 200 years are a contributing source of higher levels of carbon dioxide in the atmosphere. During that period, these levels have increased by about 28 percent. The increase in atmospheric carbon dioxide, coupled with the continuing loss of the world’s forests (which absorb carbon dioxide), has led many scientists to predict a rise in global temperature. This increase in global temperature might disrupt weather patterns and ocean currents, lead to more violent storms, and create other environmental problems.

7.7

Energy crisis

Energy crisis is a situation in which the nation suffers from a disruption of energy supplies (in our case, oil) accompanied by rapidly increasing energy prices that threaten economic and national security. The threat to economic security is represented by the possibility of declining economic growth, increasing inflation, rising unemployment, and losing billions of dollars in investment. Due to the rapid increase in population and industrialization, the demand for energy is increasing at alarming rate. Coal, mineral oils, natural gas combine supplies about 80% demand of energy in the world. The demand of energy is increasing at the rate of 2.3% per year. The nonrenewable source will not last forever, because their amount is limited. They have been formed in the earth over millions of years and they cannot be replenished rapidly when exhausted. According to the survey done in 1984 A.D, it was expected that the mineral oil reserves will have been emptied within 25 to 30 years. New oil reserves expected in the countries of Middle East Asia estimate that oil reserves will last for less than fifty years. If the mineral oil deposit is used n present ratio that will last up to 2070 A.D. but, we know that the energy demand is increasing by 2.3% per year. In this way, the mined oil will be last up to 2037. Thus, the world is likely to face a problem of energy scarcity in near future. This is called energy crisis. Thus, the future scarcity of energy sources on the earth due to overpopulation, urbanization and industrialization is called energy crisis. 3.8 Energy Conservation/Energy Saving It is a common saving that “energy saved is energy produced” that is, the solution of energy crisis is energy saving. We should try to prevent energy from being wasted uselessly. Effects on an individual and global level must be made to alert the energy crisis. In the following energy saving can be done. Components of Environment 91

1. 2. 3. 4.

As far as possible renewable energy source should be use more. As far as possible non-renewable energy source should be used less. In this way such energy sources can be preserved for the future. More alternative energy source should be developed and used. Unnecessary use of energy should be avoided.

EXERCISE A.

Very short answer questions. 1) Define energy. 2) Sate different units of heat energy. 3) Give examples of renewable sources of energy. 4) Give examples of non- renewable sources of energy. 5) Define nuclear energy. 6) Define energy crisis.

B.

Short 1) 2) 3) 4) 5) 6) 7) 8) 9) a)

answer questions. What is energy? Mention any four forms of energy with examples. Explain the importance of energy. What is fuel? Mention any three common sources of fuel in rural part of Nepal. What is a renewable sources of energy? State different renewable sources of energy. What are non-renewable sources of energy? State different non-renewable sources of energy. What is bio-fuel? Is it a renewable source of energy? Give reason What is hydroelectricity? Explain why this is called as the best alternative source of energy for renewable energy sources. State different ways of conservation of energy. Write short note on: Solar energy b) mineral c) bio-energy d) Nuclear energy e) Energy crisis d) Nuclear energy e) Energy crisis

C.

Long answer questions. 1. What is energy? Explain different renewable and non- renewable sources of energy in brief. 2. What is energy Conservation? State different ways to conserve renewable and non-renewable sources of energy. Also explain in what way the environment is affected due to the lack of energy conservation.

D.

Practical problems. a) Write a report on the conservation of energy in Nepal. b) Make a report regarding the use of renewable source of energy in your locality.




UNIT Environment and Sustainable Development 8.1 Introduction Development is one of the human activities that are linked to the environment. Development is for people. Population development and environment are three different terms which are interrelated. People role in development is vital. Development has been defined as a process by which the member of the society increase their personal and institutional capabilities to mobilize and manage resources to produce sustainable and justly distributed improvement in their quality of life consistent with their own aspirations.

8.2.1 Sustainable development Sustainable development is such a development that meets the needs of the present generation without compromising the ability of future generation to meet their own needs. The sustainable development can also be said 'Durable Development, and 'Bearable Development'. The sustainable development can be explained as the objective of fulfilling needs of present generation without damaging the resources for the future generation so, the main goal of sustainable development is to bring co-ordination among the population, resources, environment and development. The people attempt to increase the production by utilizing the limited land. The grazing area gets an end by utilizing more. The grazing area turns into desert by excessive use. Excessive use of chemical fertilizer and pesticide in cultivation reduces the fertility of land. The over use of mineral ore, mineral oil and natural gas tends to exhaust these mines. It has affected the present and future generation. So, the sustainable development is taken as the media to execute developmental activities. Without allowing problems to come thus, the proper use of agriculture sector, protection and conservation of natural resources, availability of water, reduction in chemical fertilizer, control of use of pesticide and less use, etc. come under the sustainable development. The sustainable development has emphasized to reduce pollution, develop technology and instruments to make less use of natural resources. The economic benefit is to be achieved by using natural resources wisely and rationally according to the concept of .sustainable development. It helps to raise the standard of living of the present generation. Conservation must be made along with the economic benefits from the natural resources. The important resources should be protected. Their quantitative and qualitative aspects must not be damaged. The works done in the present status, should not damage the future works. So, the emphasis is to be laid on the long run conservation of environmental means and resources. The sustainable development brings improvement in the environmental aspects related to us such as agriculture, health, education, transport tourism, etc. The sustainable development helps in the protection of environment as well.


Concept of Sustainable Development Appropriate use of Agricultural area Availability of water resource

Use of developed technology

Reduction of chemical fertilizer and insecticides

Sustainable Development

Conservation of natural resources and their

The World Commission on Environment and Development in l987 defined sustainable development as: "Sustainable development is a process in which the exploitation of resources' the direction of investment, and the orientation of technological development and institutional change meet the needs of the present generation without compromising the ability of future generation to meet their needs.

8.2.2 Importance and Need of sustainable Development The sustainable development means maintenance of the environment Development works are for human welfare. The economic development is necessary for it. If the damage on the environment due to development works not taken care of, the expected targets from the development will not be effective. Our development efforts win be unsuccessful. The importance of sustainable development are given as under: 1. Proper use of Resources: The sustainable development awakens the concept in general people to make less use of means and resources. The use of minerals, petroleum goods, drinking water, insecticides, chemical fertilizer, forests product etc. should be minimum. The sustainable development learns the concept of not to make waste while using natural resources, it helps the protection and conservation of environment through less use of means and resources of the earth. 2. Realization of Responsibility: The sustainable development brings a change in the knowledge, skill and attitude of a human being. It makes us realise the responsibility of these of the natural resources such as mine, forest, land, seafish, herbs and their protection. It creates the feeling that these resources are common property and the feeling that they cannot be-used according to an individual's will. It creates the feeling in us for the protection and utilization of common natural recourses together. It helps in the conservation of natural and social environment. 3. Development of Basic Aspects: The sustainable development lays emphasis on the development in the field of health, education, agriculture, tourism and social improvements which are most essential for human development. The protection and conservation of environment is to be carried on in integrated form while developing these aspects.


4. Development Based on Public Participation: priority is to be given to public participation in development works for the fulfillment of the goal of sustainable development. It creates interest in local people for development works and conservation of the environment. Thus, the sustainable development increases the participation of all types of people in the protection and conservation of the environment. 5. Determination of the Limit of Development: People need limited and effective means and resources to fulfill their basic needs. Yet people do more development works out of temptation. More use of limited and non-renewable means and resources of the earth will make them exhausted. So, the development works should be done within the bearing capacity of the earth. Hence, the sustainable development creates the concept of how much to develop in policy makers and other persons involved in development. 6. Long Term Vision: The sustainable development had suggested the target of economic and social development without displacing the means and resources of the earth. It makes an effort to develop the concept of maintaining today's work for the future and to preserve natural resources for coming generation. So, the sustainable development helps in developing long term thinking and contributes to the protection and conservation of the environment.

8.3 Role of education in sustainable development There is a great role of education for sustainable development. The main role is to the provide the vision that seeks to an power people to assume responsibility for creating a sustainable future. For the education on sustainable development to be an effective tool for engaging people in negotiating a sustainable future, decision making and acting on them must first address the way we think about sustainable development and about education in general. Generally, the role of education for the sustainable development includes. 1. Envisioning: being able to imagine a better future. The premise is that if we know where we want to go, we will be better able to work out how to get there. 2. Critical thinking and reflection: Learning to question our current belief system and to recognize the assumptions underlying our knowledge, perspective and opinions. Critical thinking skills help people learn to examine economic, environmental, social and cultural structures in the context of sustainable development. 3. Systemic thinking: acknowledging complexities and looking for links and synergies when trying to find solutions to problems. 4.

Building partnerships: promoting dialogue and negotiation, learning to work together.

5.

Participation in decision-makings: empowering people.

8.4 Eco- Technology in Development Eco-technology is an applied science that seeks to fulfill human needs while causing minimal ecological disruption, by harnessing and subtly manipulation natural forces to leverage their beneficial effects. Eco-technology integrates two complementary fields of study: the 'ecology of techniques' and the 'techniques of ecology' requiring a substantial understanding of the structures and processes of ecosystems and societies. All sustainable engineering that can reduce damage to ecosystems, adopt Components of Environment 95

ecology as a fundamental basis, and ensure an orientation of precaution in the implementation of the conservation of biodiversity and sustainable development may be considered as forms of ecotechnology. Eco- technology approaches an issue from a holistic point of view. For example, remediation of rivers should not only consider one single area. Rather, the whole catchment area, which includes the upstream, middle stream and downstream sections,should be included in evaluation for effective remediation. From the viewpoint of ecosystem, activities that are taken for human economic activities should strive to reduce impacts on nature as much as possible. Sustainable development requires the implementation of appropriate environment friendly technologies which are both efficient and adapted to local conditions. Eco-technology allows improvement in economic performance while minimizing harm to the environment by:      

Increasing the efficiency in the selection and use of materials and energy sources, Control of impacts on ecosystems, Development and permanent improvement of cleaner processes and products, Encouraging more environmentally benign (favorable) behavior, Introducing environmental management systems in the production and services sectors, and Developing activities for increasing awareness of the need for environmental protection and promotion of sustainable development by the general public.

Mastering development and application of eco-technology in industry and the service sector is, therefore, a key requirement. The quality of eco-technological knowledge depends on the efficiency of the multidisciplinary synthesis of knowledge and skills in natural sciences and technologies, information and communication sciences, economics, legal and social sciences. Application of Eco-technology in Development Solid waste is one of the major problems in environment. With the increasing population and increasing industrial activity, the generation of solid waste is also increasing manyfold. Due to the unbalanced production in organic/inorganic wastes, it produces negative impact on various ecosystems and human societies. It is the fact that the various sectors also possess pressure to the related institutions to solve this problem.

Non-government Organization Consumers Group

Media

Reduction in Solid waste Other

Laws

Economic


The trend of the solid waste management is as follows:     

In 1960s, the solid wastes from the industries were thrown freely. In 1970s, there was the thought: treatment of effluents before disposal. In 1980s, there was the thought: reduction of effluents. In 1990s, there was the thought: reuse and reduce effluents in the sources. In 2000s, (at present) there has been a thought: eco-friendly production.

8.5 Eco-friendly Lifestyle Have you heard the entire hullabaloo about pollution and its adversity? It's a hot topic these days. Naturally, if the common person is experiencing the tribulations, s/he is bound to get restless. But how much is it affecting? People just talk and then forget about the current issue on pollution. It is not their fault. There are not many ways to curb the problems since we are all at the mercy of the scientific encroachments. But, just by being conscious about the immediate repercussions around us will make no difference. We have to find ways to manage wastes before situation gets unmanageable. 'Go Green'- save Mother Earth! If you have options to replace synthetics with biodegradable materials, implement. Implement, so that you set an example for your spawn that's constantly imitating your actions. Introduce eco-friendly materials to your children; contribute towards restoring balance in nature. They are believed to be very artistic and beautiful. Many of them look simply trendy. You have made your way here because you are a concerned and caring individual looking for ways to help reduce your carbon footprint and live a more eco-friendly lifestyle. There are so many things we can do that will make a small but significant impact on the future health of our planet. 1. Fresh Environment: Uses of ecofriendly materials reduce the pollution to the environment. Huge machines, trucks, and generators have to be used according to the limit of the pollution of the country. Use of public vehicles should be prioritized and they should be timely maintained through servicing as well.

Fig: Public Vehicles

2. Conservation of energy: Energy should be conserved for the future generation. The transportation (which needs fossil fuels, diesel or petrol) should be used only in necessary work. For short distance. Let's not use vehicles. Use bicycles as far as practicable. The vehicles used should be well conditioned which produce very little pollution to the environment. Here are some very simple steps you can take right now to reduce energy consumption around your home:    

Always turn off lights when you leave a room. Don't leave appliances on standby and don't leave laptops/mobile phones on charge unnecessarily. Only boil as much water as you need in your electric kettle. Use your washing machine and tumble dryer efficiently - one full load will use less energy than two half loads. Check your hot water thermostat - make sure it is set no higher that 490C. Components of Environment 97

    

Turn your air conditioner temperature setting up to 25 0C. Close curtains and doors during the heat of the day to reduce the work your air conditioner needs to do. Close curtains and doors in the evening to conserve heat during winter months. Set your hot water system to only heat water once per day rather than all the time. Take shorter showers to save on water heating and water consumption.

3. Green eco-friendly home: The renewable resources should be used in construction materials, decorative materials and other materials which should meet our feeling and eco. friendliness, for example, doors, windows. furniture. carpets, doormats, colours, etc. These things should be green, non-hazardous, re-usable or recyclable. The colours used should be non-hazardous and low-volatile organic compounds. 4. Pollution free eco-friendly kitchen: In developing countries like Nepal, a valuable part of the energy is consumed in cooking purposes. The cooking place should be smoke free with less consumption of energy as well as water. The energy used should be renewable, the tools used in the kitchen should be hazard free and soaps chemical free. The shampoo and cream used should be free from hazardous chemicals. 5. Hazardous chemical free organic cotton: The cotton used should be made of organic cotton as well as silk. Naturally produced cotton should be used other than that which has used pesticides or insecticides. 6. Use of eco-stationery goods: Eco- centric papers, especially recycled ones, are nowadays commonly used for making notebooks, textbooks and binders. Manufacturers in Nepal and around the world are also creating consciousness and distributing earth-friendly books. Eco-friendly stationery, especially handmade paper, faces one drawback. Since the production includes much more skill and artistry than the usual paperFig: Eco-stationary goods making technique, the cost of the end result is a little higher than the regular ones. This eco-stationery goods pinches the pockets of the users and, the handmade paper seems to be more of an expensive stationery item. But depletion of forests is a matter of concern and in midst of this critical phase, the handmade paper and stationery prove to be blissful. 7. Recycling and re-use: In our homes, various wastes (paper, plastics, tins, bottles or organic materials) are produced: First of all, the organic and inorganic materials are separated. Out of these, the inorganic materials are re-used for various purposes and the remaining should be sent for recycling. 8. Reduction of wastes: Estonian clean-up project is really inspiring! To bring the waste issue further we would like to talk about zero waste. It is the concept of re-use of waste; concept where


waste can become resource. How that could be possible, you will ask. But there are existing communities that produce no waste! We recognize that nature is cyclical and has no waste. Our industrial pathways must follow this design set by nature if we are to become a sustainable. Zero Waste (ZW) supports sustainability by reducing extraction from, and eliminating waste to, nature, improving economic efficiency and making more resources available to all. 9. Preparation of compost: The various organic materials separated from waste (vegetable and fruit trimmings) available in households, groceries, and restaurants are rich in nitrogen and other nutrients, including trace elements. If you decide to build your compost heap gradually, kitchen waste can be put in a tight-lid container until enough has been accumulated for a layer. Sawdust placed at the bottom of the container absorbs the juice of the garbage. An occasional sprinkling of limestone or wood ash helps prevent odour, discourages flies from laying their eggs, and neutralizes the acidity of the raw garbage. Manure or rich soil can be added to give the kitchen garbage a good start on composting. 10. Organic farming: Organic farming is the system of agriculture that excludes the use of synthetic pesticides, growth hormones, antibiotics, genetically modified seeds and animal breeds, and irradiation. Organic farmers, instead, rely on ecosystem management, including the use of pesticides and fertilizers derived from plants, animal wastes, and minerals. They incorporate biological methods, such as the use of one organism to suppress another, to help control pests. The methods used in organic farming seek to increase soil fertility, balance insect population, and reduce air, soil, and water pollution. 11. Use of renewable energy: Forms of energy that are renewable are not based on fossil fuels. Examples of alternative energy are Bio-fuel; Geothermal Energy; Solar Energy; Tidal Energy; and Wind Energy. Consumers may also consider environmental measures such as purchasing "green Power" when it is offered by a local utility. "Green power" is usually more expensive but L relies on renewable and environmentally friendly energy sources, such as wind turbines and geothermal power plants. 12. Reduce the production of the greenhouse gases: Temperature increment is an effect of greenhouse gases (carbon dioxide, methane, nitrous oxide, and ozone). Most of the greenhouse gases are evolved from industrial countries. In order to reduce such gases, the consumption of fossil fuels should be reduced. There should be a treatment plant along with the industry. The developed country should co-operate the developing countries to reduce such gases. 13. Green environment: Environment should be green inside and outside our homes. The bare land, hills, free land should be planted by appropriate species of plants. Although

Fig: Green Environment Components of Environment 99

greenery was originally concerned mainly with timber production, it now also involves the management of grazing areas for domestic livestock, the preservation of wildlife habitats, watershed protection, and the development of recreational opportunities.

EXERCISE A.

Very short answer questions 1) Define development. 2) Define sustainable development. 3) What is eco- technology? 4) What is pollution free eco-friendly kitchen? 5) What is organic farming?

B.

Short answer questions 1) What is development? Explain the concept of sustainable development sustainable development. 2) Describe the role of education in sustainable development. 3) What is eco-technology? Explain the importance of eco-technology in development. 4) Describe in brief about eco-friendly life style.

C.

Long Answer questions 1) What is sustainable development? Describe the importance of sustainable development. 2) What is eco- technology in development? Describe the importance of sustainable development. 3) What is eco-friendly life style? Describe.

D.

Practical problem 1) Write a report on eco –friendly life style.




Environment Science Class âIX

Environment Science Class âIX

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