in Iraq. I would like to thank Basra Water Office staff for their great help. ...... K, Na,Ba,. 9- Oven. Memmert Germany. 10- Water bath. Memmert Germany ...... Fabricius, K, De'ath, G, McCook, L, Turak, E & Williams, DMB 2005, 'Changes in algal ...
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Dedication 7RKXPDQLW\¶VPHVVHQJHU0XKDPPDG SHDFHEHXSRQKLP DQGWRDOOKRQHVW people on the planet« 7RP\GHDUPRWKHUDQGIDWKHU« 7RP\EURWKHUVDQGVLVWHUV« To my lovely wife and my gorgeous sons Ahmed, Zainab, Ali, Hussein, Eman DQG7DEDUDN +DONRPD « I dedicate my work with my love.
Jassim 2012
iii
Acknowledgement Praise be to God who helped me complete this thesis. First and foremost, I would like to express my gratitude to my supervisor, Dr Ann Peterson, whose encouragement, guidance and support from the outset and throughout enabled me to develop my understanding, execute my research, and compile this final piece of work. I would also like to thank my second supervisor Dr Wesal Hassan for her valued support from beginning to end. Thanks must also go to my third supervisor Dr Nick Callow for his support with my technical work. I am indebted to the Australian and Iraqi governments who gave me this opportunity to complete my Masters degree. I also wish to express my great thanks to AusAid organization staff, especially those who work at The University of Queensland, for their support and encouragement: Laura Anderson, Sue Quarton, Claudia Morales, Darren Wise, Michael Biscak and others. Special thanks to Dr Mahdi Al-Kasey, the technical deputy of the agriculture ministry for his support. This thesis would not have been possible without the support of Dr Malik Hassan, Head of the Marine Science Centre at Basra University ± he has my respect and thanks. And special thanks to Dr Abdul Al- Kareem for his support and kindness. 0U 0LFKDHO 7REH¶V VXSSRUW NLQGQHVV DQG KHOS WKURXJKRXW DUH JUHDWO\ appreciated, and my thanks also go to Mr Abdullah for his support in relation to the technical parts of my research. Without the following people, this thesis would not have been possible ± thanks must go to: the Marine Sciences Centre staff who supported me throughout the
iv
practical parts in Iraq: Dr Hammed Al-Saad, Dr Abdul Al-Zahra Al-hello, Mr.QassimM.Al-Aesawi, Mr.Wala'a, M.Al-Musawi, Mr.WissamR.Mutasher, Mr.Meelad A. Hussein, Ms. Dunia K. Al-Kazahy, Ms. Zuhair A. Abdulnabi, Ms.Yussra J. Alawy, Ms. Nadia K. Mehsen, Ms. Rehab Salim, Ms. Methak Abrahem Abod, Mr. Ahmed Yousif Hamood, and Mr.FarsHameed. Aside from personal effort, the success of any project is largely dependent on the encouragement and guidance of many others. I take this opportunity to express my gratitude to the School of Geography, Planning and Environmental Management (GPEM) staff and Students Services staff, with special thanks to Dr David Rowland and Ms Jacqui Harding. I also want to extend my thanks to the IT staff, librarians and endnote specialists for their support. Special thanks also to the Director of Studies at ICTE, Mr. Stephen Heap, and all the teachers who helped me learn English. I wish to avail myself of this opportunity to express a sense of gratitude, love and thankfulness to my mother and father, my brothers and sisters, and all my relatives and friends for their support, help and encouragement. Special thanks to my brother Qassim for his patience and support to my family throughout my entire period of study. I am indebted to my many colleagues at the Basra Agriculture Directorate who have supported me. I also owe my friends Leftah, 1DGHUDQG0RD¶G great thanks for the role they played in supporting me during the practical parts of my thesis in Iraq. I would like to thank Basra Water Office staff for their great help. There are many others who supported me in a variety of ways throughout this project. To all of them I offer my sincere regards and blessings.
v
Table of Contents Table of Contents ................................................................................................ vi List of Figures ................................................................................................... viii List of Abbreviations .......................................................................................... xi Chapter One : Introduction ...................................................................................1 1.1
Introduction ..............................................................................................1
1.2
Problem statement ....................................................................................2
1.3
Research question.....................................................................................3
1.4
Research aim ............................................................................................3
1.5
Research objectives ..................................................................................4
1.6
The importance of the research ................................................................4
1.7
Research outline .......................................................................................5
Chapter Two : Literature review...........................................................................6 2.1
Introduction ..............................................................................................6
2.2
Water quality ............................................................................................6
2.2.1
Chemical characteristics of water quality ..........................................6
2.2.2
Physical characteristics of water quality .........................................8
2.3
Factors that can affect river water quality..............................................10
2.3.1
Discharge and river water quality ....................................................10
2.3.2
Sources of pollution in river catchments .........................................12
2.3.3
Tidal flow of salt water ....................................................................16
2.4
International standard for water quality ..............................................16
2.5
Conclusion..............................................................................................18
Chapter Three : Study area and methodology ................................................... 20 3.1
Introduction ............................................................................................20
3.2
Study site................................................................................................20
vi
3.2.1
Hydrology........................................................................................21
3.2.2
Climate.............................................................................................22
3.2.3
Water management practices .........................................................22
3.3
Methodology ..........................................................................................24
3.3.1
Sample stations and data collection .................................................24
3.3.2
Equipment........................................................................................30
3.3.3
Data collection ................................................................................31
3.4
Statistical analysis ..................................................................................39
3.5
Conclusion..............................................................................................40
Chapter Four : Results and discussion ............................................................... 41 4.1
Introduction ............................................................................................41
4.2
Water quality field measurement results................................................41
4.2.1
pH.....................................................................................................41
4.2.2
Dissolved oxygen (DO) ...................................................................44
4.2.3
Water temperature TºC ....................................................................46
4.2.4
Salinity .............................................................................................48
4.2.5
Electricity conductivity (EC) ...........................................................49
4.3
Water type analysis ................................................................................52
4.3.1
Hydro-chemical formula and water type .........................................52
4.3.2
Classification of water quality .........................................................56
4.4
Identification of the salt wedge arrival point .........................................58
4.5
Water discharge, water elevation and EC ..............................................59
4.5.1
Water discharge and water elevation ...............................................59
4.5.2
Water elevation and EC ...................................................................61
4.5.3
Water discharge and EC...................................................................64
4.6
Conclusion..............................................................................................67
vii
Chapter Five : Conclusions and recommendations............................................ 68 5.1
Introduction ............................................................................................68
5.2
Research statement and key findings .....................................................68
5.3
The study scope limitations....................................................................70
5.4
Recommendations ..................................................................................71
5.5
References ..............................................................................................73
5.6
Appendices .............................................................................................81
List of Figures Figure 1.1The location of Shatt Al-Arab River in South of Iraq...............................2 Figure 2.1 Rating of water samples in relation to salinity and sodium hazard. ......18 Figure 3.1 Water allocation in Iraq. .........................................................................24 Figure 3.2 Location of the Shatt Al-Arab River and the water monitoring stations......................................................................................................................25 Figure 3.3 Station 1 Al-Sindibad .............................................................................28 Figure 3.4 Station 2 Mhelah.....................................................................................28 Figure 3.5 Station 3 Al-Seebh..................................................................................28 Figure 3.6 Station 4 Al-Fadaghia.............................................................................29 Figure 3.7 Station 5 South Al-Fadaghia ..................................................................29 Figure 3.8 Station 6 Al-Fao .....................................................................................29 Figure 3.9 Lamotte JT-1 Water samples collector, Field measurements. ..............31 Figure 3.10 Aqua Read GPS Aqua meter ................................................................32 Figure 3.11 WTW multi-meter ................................................................................32 Figure 3.12 Field parameter measurements .............................................................33 Figure 3.13 Water discharge equipment (ADCP)....................................................37 Figure 3.14 Water discharge field work ..................................................................38 Figure 3.15 Water elevation instrument (Rugged Troll and Wine ±Situ Sync) ......39 Figure 3.16 Loggers cover ......................................................................................39 Figure 4.1 pH values in stage one (September, 2011) in the Shatt Al-Arab River. 42 Figure 4.2 pH value in stage four (January, 2012) in the Shatt Al-Arab River.......43 Figure 4.3The average pH values in all stages of measurement..............................44 Figure 4.4 DO in stage two (December, 2011) in the Shatt Al-Arab River. ...........44 Figure 4.5 DO in stage four (End of January 2012) in the Shatt Al-Arab River.....45 viii
Figure 4.6 DO average values during the three stages (December, early Janaury and end of January). .................................................................................................46 Figure 4.7 Water temperature in stage one (September, 2011) in the Shatt AlArab River................................................................................................................46 Figure 4.8 Water temperature in stage four (end of January, 2012) in the Shatt Al-Arab River. .........................................................................................................47 Figure 4.9 Average temperatures during the four stages (September, December, early January and end of January). ..........................................................................47 Figure 4.10 SAL. in stage two (December, 2011) in the Shatt Al-Arab River. ......48 Figure 4.11 SAL. in stage four (end of January) in the Shatt Al-Arab River. ........48 Figure 4.12 The average salinity value during the three stages (December, early January and end of January) ....................................................................................49 Figure 4.13 EC at stage one (September 2011) in the Shatt Al-Arab River. ..........50 Figure 4.14 EC at stage four (end of January 2012) in the Shatt Al-Arab River. ...50 Figure 4.15 The average EC values during the four stages (September, December, early January and end of January). ........................................................50 Figure 4.16 Salt map (stations and distance from the Gulf of Arabia )..................59 Figure 4.17 The relationship between water elevation and water discharge at AlSindibad station (St. 1) in December in the Shatt Al-Arab River. ..........................60 Figure 4.18 The relationship between water elevation and water discharge at Mhelah station (St. 2) in December in the Shatt Al-Arab River. ............................60 Figure 4.19 The relationship between water elevation and water discharge at AlSeebh station (St.3) in December 2011 in the Shatt Al-Arab River........................60 Figure 4.20 The relationship between water elevation and water discharge at AlFao station (St. 6) in December 2011 in the Shatt Al-Arab River...........................61 Figure 4.21 Water elevation and EC at Al-Sidibad station (St.1) in December, 2011. .........................................................................................................................62 Figure 4.22 Water elevation and EC at Mhelah station (St. 2) in December, 2011. .........................................................................................................................63 Figure 4.23Water elevation and EC at Al-Seebh station (St.3) in December, 2011. .........................................................................................................................63 Figure 4.24 Water elevation and EC at Al- Fao station (St.6) in December, 2011. .........................................................................................................................64 Figure 4.25 Water discharge and EC at Al-Sindibad station (St.1) in September, 2011. .........................................................................................................................65 Figure 4.26 Water discharge and EC at Mhelah station (St.2) in September, 2011. .........................................................................................................................65
ix
Figure 4.27 Water discharge and EC at Al-Seebh station (St.3) in September, 2011. .........................................................................................................................66 Figure 4.28 Water discharge and EC at Al-Fao station (St.6) in (September, 2011). .......................................................................................................................66
List of Tables Table 2.1 The U.S. Salinity Laboratory water evaluation criteria...........................17 Table 3.1Sample stations .........................................................................................26 Table 3.2. Instruments used in field and lab work...................................................30 Table 3.3 Field parameter measurements ................................................................33 Table 3.4 Illustration of some parameters which were measured in the lab. ..........35 Table 4.1Maximum& Minimum values of cations and anions (mg/L)...................54 Table 4.2 Cations and Anions expressed as meq percentage contribution and dominance and the hydro chemical formula of water in the Shat Al-Arab River...55 Table 4.3 The Shatt Al-Arab water classification for irrigation purposes according to US-Salinity lab criteria. ......................................................................56 Table 4.4 Evaluation of the water quality according to the (WHO 2004) drinking water standard............................................................................................57
x
List of Abbreviations Symbol
Meaning
St. 1
Station 1 (Al-Sindibad)
St. 2
Station 2 (Mhelah)
St. 3
Station 3 ( Al-Seebh)
St. 4
Station 4 (Al-Fadaghia)
St. 5
Station 5 (South Al-Fadaghia)
St. 6
Station 6 (Al-Fao)
EC
Electricity conductivity
pH
Acidity
SAL
Salinity
DO
Dissolved Oxygen
Tº
Temperature
Cl
Chloride
SO4
Sulphate
Ca
Calcium
Mg
Magnesium
HCO3
Bicarbonate
K
Potassium
Na
Sodium
TDS
Total dissolve solid
WHO
World Health Organisation
SAR
Sodium absorption ratio
xi
Abstract This study was conducted from September 2011 to January 2012 to evaluate the water quality of the Shatt Al-Arab River based on some chemical and physical parameters, and to investigate the impact of water river discharge and water elevation on electrical conductivity (EC). It also attempted to identify the extent of the impact of the Arabian Gulf salt wedge on the Shatt Al-Arab River. Water samples were collected from six stations along the final 127km of the river to its mouth in the Gulf. The stations were: Al-Sindibad (St.1), Mhelah (St.2) AlSeebh (St.3) Al-Fadaghia (St.4), South Al-Fadaghia (St.5) and Al-Fao (St.6). The parameters investigated were: EC, salinity (SAL), acidity (pH), dissolved oxygen (DO) and water temperature (Tº). The lab measurements were conducted to investigate the levels of chloride (Cl), potassium (K), sulphate (SO4), sodium (Na), calcium (Ca), magnesium (Mg), and bicarbonate (HCO3). Standard lab methods were used to measure these cations and anions. The results indicated that the pH value was between 7.03 and 8.99, which can be considered normal for Iraqi water as it tends to be alkaline. However, there was a slight increase in winter pH levels when compared to the first stage in September. There was also a slight decrease in the value at St. 6 compared with other stations, which is abnormal and needs to be studied in more detail. Although the results showed that the Shatt Al-$UDE 5LYHU¶V ZDWHU LV ZHOO oxygenated at all stations, averaging about 9 mg/L, there was some decline in that value recorded at St 6, which averaged about 7mg/L- due to the impact of salt water from the Arabian Gulf. It is also important to mention that the DO lowest value (4.73) was recorded at St. 6 which was under the normal range of those parameters. The water temperature showed seasonal variations with a maximum of 32.10ºC in September and a minimum of 10.40ºC in winter, all of which can be considered normal by Iraqi standards. SAL and EC values were higher towards the Arabian Gulf and decreased further away. SAL values
xii
ranged between 1.07 and 20.12 ppt and EC had the same trend with the highest value being48.40mS/cm at Al-Fao station (St.6) in September, while the lowest value was 1.67mS/cm at Al-Sindibad (St.1) in December. Generally all the above parameter measurements saw significant differences based on the station, the month the measurements were taken, and the time of day at which those measurements were taken. There were no significant differences observed in relation to water depth. Regarding the salt wedge impact, the results showed that the salt wedge entered the river stream at a point somewhere between Mhelah station (St.2) and AlSindibad station (St.1) in September, and returned somewhere between AlSeebh station (St.3) and Al-Fadaghia station(St.4) in December and January. Water discharge and the impact of tidal movement from the Gulf had a direct impact on changing almost all of the parameters, with a very clear impact on EC levels found particularly at those stations closest to the Gulf. Water elevation was also affected by the amount of water discharge and the tidal movement. The lab investigations showed that the Shatt Al-$UDE 5LYHU¶V ZDWHU ZDV dominated by sodium and chloride ions as a result of the Gulf impact and through other sources of pollutants. The cations and anions can be arranged: Camg-sodium ±So4 Chloride at all stations in January, while a different pattern was evident in winter: St.1 Mg-Ca-Sodium ±So4-Hco3-Chloride; St.2 Mg-NaCalcium-So4-Cholride; St.3 Ca-Mg-Sodium-Chloride; St. 6 Ca-Na-MgnisumSo4-Cl. Finally, the water quality of the Shatt Al-Arab River can be evaluated according to the irrigation standard (US-Salinity Lab) as C4S1 which was saline to extremely saline with low Sodicity hazard. According to World Health Organisation standard of drinking water (WHO, 2003), the water is unsuitable for drinking.
xiii
Chapter One: Introduction 1.1 Introduction Fresh water is a fundamental resource, important to all ecological and socioeconomic activities, including food and energy production, transportation, waste disposal, industrial development, and human health, yet fresh water resources are unequally and irregularly distributed, and some regions of the world are extremely water short. Water and water supply systems are increasingly likely to be objectives of military action and instruments of war and will be increasingly impacted by global climate change, which makes water supply and demand more problematic and uncertain (Gleick 1993; Khublaryan & Moiseenko 2009). The quality and quantity of water are FUXFLDO IDFWRUV IRU PDLQWDLQLQJ DQG SURWHFWLQJ SHRSOH¶V KHDOWK FRQVHUYLQJ biodiversity, enhancing the aesthetic and recreational values of nature, ensuring the supply of food and for manufacturing and other industrial production (Khublaryan & Moiseenko 2009). A significant water shortage problem, predicted to occur in the near future, has raised concern among Middle Eastern nations (Turan 1993). Like many other parts of the world, Iraq has also suffered from the impacts of water shortages due to the decline in the discharge of water from its neighbouring countries (Turkey, Syria and Iran) (Janabi 2007; Al-Mahmood 2008; Janabi n.d.).It has been estimated that the discharge of the Tigris and Euphrates Rivers in the 1970s was about 48 billion m3 and 28 billion m3 per year respectively, yet this amount of water has declined to just 20.90 and 19.7 billion m3 per year (Janabi 2007).This decrease occurred as a result of the construction of dams in neighbouring countries, especially in Turkey and Syria. The Shatt Al-Arab River, which is the focus of this study (Figure 1.1), is at the confluence of the Tigris and Euphrates Rivers in the south of Iraq, and extends about 190 km before its water empties into the Arabian Gulf (Saad 1980; Abdullah 1990; Hussein et al. 1991). Its water discharge depends primarily on the discharge of the Tigris and Euphrates Rivers and other important tributaries such as Al-Karun and AlSweeb (Abdullah 1990). 1
The water quality of this river has worsened as a result of a significant decline in water discharge affecting Iraqi rivers in recent years (Al-Mahmood, Al-Shawi & AlImarah 2008; Hassan et al. 2011). In 2009, it was recorded that the level of electrical conductivity increased to about 15.65 mS/cm in the Shatt Al-Arab River at Al-Fao city, which is located at the southern point of Iraq (Hassan et al. 2011). Because of this and the huge damage which could possibly occur as a result of the salt level increases, wide concern has been raised about this issue among Iraqi people, especially those who are living in the south of Iraq(Basra Province Council 2011).
Figure 1.1The location of Shatt Al-Arab River in South of Iraq (Google map,2012)
1.2 Problem statement The Shatt Al-AraE5LYHULVDQLPSRUWDQWZDWHUUHVRXUFHIRU%DVUDFLW\,UDT¶VVHFRQG largest city, with many household, agricultural and industrial activities reliant on its waters. However, the water quality of this river is essentially affected by the water quality and quantity of the Euphrates and Tigris Rivers (Jawad 1994). The salinity of the Shatt Al-Arab River has been influenced by many factors, including the size, quantity and freshness of water received by this river; the variability of the water 2
discharged into it; the impact of temperature and sunshine; the amount of rainfall and evaporation rates; and the impact of the type of land areas that this river crosses (Hussein et al. 1991). These factors have impacted on water quality, especially the salt level, which has continually increased in the Shatt Al-Arab River over recent years. The problem of impaired water quality has affected many people who live around the Shatt Al-Arab River. It has caused damage to agricultural land, crops, date palm trees and livestock. The issue of salt water pollution is also of concern to many Iraqi local people, scientists and politicians (Janabi 2007). The first symptoms of pollutants and lack of discharge appeared in the Shatt Al-Arab River due to its location in the downstream paUWRI ,UDT¶V ZDWHUV\VWHP %\ XQGHUVWDQGLQJ WKH PDLQ FDXVHV RI WKLV LVVXH WKH ULYHU¶V ZDWHU PDQDJHPHQW VWUDWHJ\ FDQ EH LPSURYHG WR include workable solutions that address the root causes or at least tackle the side effects of the negative change in the riYHU¶VZDWHUTXDOLW\ There are several different opinions as to the main causes of salt water pollution of the Shatt Al-Arab River. The present study will focus on water quality in the Shatt Al-Arab River in terms of salt contamination by looking at the main causes and possible factors which could contribute to this situation.
1.3 Research question The specific question that this research addresses is: What is the level of salt contamination in the Shatt Al-Arab River and is it affected by tidal influences from the Gulf of Arabia?
1.4 Research aim The main aim of this research is to investigate water quality in the Shatt Al-Arab River and in particular to analyse the nature of tidal flows of the Arabian Gulf and their impacts on salinity levels in the Shatt Al-Arab River, and to analyse what the possible impact of the decline of river water discharge is on the water quality. This information will enhance the ability of decision makers to improve water quality in this river. 3
1.5 Research objectives The objectives that this research addresses are to: 1- Analyse trends in the water quality of the Shatt Al-Arab River during recent GHFDGHV DQG WR HYDOXDWH WKH ULYHU¶V ZDWHU TXDOLW\ DFFRUGLQJ WR D VWDQGDUG international water model of assessing water quality. 2- Identify and analyse the extent of salt contamination from sea water in the Shatt Al-Arab River and the key factors responsible for this. 3- Identify key recommendations which can be implemented to address the findings of this research.
1.6 The importance of the research The Shatt Al-Arab River is very important for a variety of social, economic and environmental reasons. Firstly, the river, until the 1980s, was the main source of fresh water in Basra province (which has the second largest provincial population in Iraq) and the people depend upon it daily for their water use. However, saline contamination has been noticed since the 1980s (Al-Mahmood, Al-Shawi & AlImarah 2008). Water is also used in the irrigation of orchards, agricultural fields, animal breeding and fish farms. The deteriorating water quality in the river will inevitably lead to direct negative effects on human health as well as to negative effects on the most vital sectors such as agriculture, both animal and plant (Hassan et al. 2011). Also, this would increase the cost associated with providing clean water for drinking and agricultural irrigation projects. Secondly, in the province of Basra, many important industries rely on river water. These include paper production, fertilizer, petrochemical and power plants, and the oil industry. The deterioration of water quality and quantity negatively affects these industries and will result in increased costs to provide a suitable quality of water for such industries. Thirdly, from an environmental perspective, despite the lack of scientific studies on the aquatic environment and its vulnerability to change, there is clear evidence that 4
WKHDTXDWLFHFRV\VWHPVKDYHEHHQQHJDWLYHO\DQGVLJQLILFDQWO\DIIHFWHGE\WKLVULYHU¶V increasing levels of salt contamination which, in turn, exposes many organisms (e.g. Barbus sharpie, B. xanhoptherus and B. grypus) to the threat of extinction (Al-noor 1998). This is especially true in the downstream reaches, particularly at the confluence of the Shatt Al-Arab River (freshwater) with the Arabian Gulf (salt water), which is a unique environment for many organisms that live in this area. Fourthly, by knowing the extent of deterioration in the Shatt Al-Arab River and by identifying the main causes accurately, policy makers will be more able to successfully find cost effective and sustainable solutions to minimize the effects of this serious problem.
1.7 Research outline The first chapter of this thesis is the introductory chapter. In the second chapter the previous studies relating to water quality and salinity increase in rivers will be reviewed to understand the main aspects of this issue and to choose the appropriate methodology to conduct this research. In the third chapter the study area, materials and methodology which were used in this work will be explained as well as the sample collection method and data analysis. The results and data analysis will be discussed in detail in the fourth chapter. Finally, the conclusion, with some valid recommendations, will be given at the end of this study in Chapter Five.
5
Chapter Two: Literature review 2.1 Introduction The overall purpose of this chapter is to review the literature to identify the main factors which impact on river water quality and to ascertain which chemical and physical parameters can be measured in order to assess the quantity and quality of water in the Shatt Al-Arab River. A further aim is to choose the appropriate methodology to conduct this research.
2.2 Water quality Globally, river water has been used for many purposes such as domestic, agricultural and industrial activities. As well, it has been considered the main factor which can determine the ground water level in some regions. Water demand has been increasing due to exponential population growth, and the development of agricultural and industrial sectors. Meanwhile, water quality has deteriorated as a result of these activities. Concern has been raised about the quality and quantity of water, and management programs for water quality are needed to control water degradation (Samuel 2012).A river can be considered to be a system comprised of both the main watercourse and its tributaries, in which there is a one-way flow of dissolved matter, DVZHOODVSDUWLFOHVRIPDWWHUDULVLQJIURPERWKKXPDQDQGQDWXUDORULJLQV$ULYHU¶V quality at any stage is influenced by several main factors, which include the lithology of the surrounding basin, and inputs from the atmosphere, climatic conditions, and human activity (Bricker & Jones 1995 cited in Shrestha & Kazama 2007).
2.2.1 Chemical characteristics of water quality Since the interaction between an organism and its environment is a fundamental principle in the science of the aquatic environment, chemical measurements are needed to assess water quality and clarify the impact of these factors on aquatic life (Hussein et al. 1991). There are many aspects which could affect the chemical characteristics of water in the Shatt Al-Arab River, such as the nature of the region 6
through which the river passes, the quality of ground water in the region, the impact of salt water from the Arabian Gulf, which mixes with the Shatt Al-Arab in tidal movements, and in addition, the impact of high temperatures during the long summer which increases the evaporation rates and acceleration or deceleration of biological processes(Al-Asadi 1983
; Glaim 1997; Al-Maliky 2002; Atta 2004; Mossa 2006;
Al-Mahmood, Al-Shawi & Al-Imarah 2008).
a.
Electricity conductivity (EC)
EC level is one of the important factors which has been taken into consideration in a range research conducted on the Shatt Al-Arab River (Al-Moussawi 1992; Glaim 1997; Al-Maliky 2002; Hassan et al. 2011). In general the previous studies have shown high concentrations of salt in the river, especially in the summer, as opposed to the winter season. This has been attributed mainly to the high temperatures and evaporation rates in summer, which reduce the water level and increase the salinity, compared with the low temperatures and higher rainfall during the winter seasons (Al-Moussawi 1992; Al-Hajjaj 1997; Al-Maliky 2002; Atta 2004). Al-Moussawi (1992) also indicated that the EC level of the Shatt Al-Arab River has increased over time. There has also been an increase in the chlorine, calcium and magnesium concentrations over time and this has been attributed to high evaporation rates, combined with an increase in the amount of pollutants such as human waste, sewage and hospital waste entering the river from different sources (Abdullah et al. 2001; AlAmarah et al. 2001; Hussein et al. 2002; Al-Mahmood, Al-Shawi & Al-Imarah 2008).
b.
Acidity (pH)
The level of acidity in the water is mainly based on dissolved gases, cations and anions (Hussein et al. 1991). Generally, the pH value of IraT¶V water is alkaline (between 7.17 and 8.38) (Glaim 1997). These recordings are similar to the values identified for the Shatt Al-Arab River (Al-Suwaij 1999; Al-Essa 2004; Atta 2004; Mossa 2006). This alkalinity has been attributed to the high level of carbonate and 7
bicarbonate in this river (Al-Zubaidi 1985 ; Ghanie 1996) and also the high temperatures, which cause increases in the level of evaporation and hence a rise in calcium salt concentrations (Abdullah 1989).
c.
Dissolved oxygen (DO)
A high level of dissolved oxygen is a good indicator of a healthy aquatic environment for living organisms (Hussein et al. 1991). In many studies which have measured the biological oxygen dissolved (BOD) in the Shatt Al-Arab River, dissolved oxygen concentrations did not fall to critical values (i.e.
