Hydrological Sciences—Journal—des Sciences Hydrologiques, 43(3) June 1998
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Assessment of point and non-point sources of pollution using a chemical mass balance approach
C. K. JAIN, K. K. S. BHATIA & S. M. SETH National Institute of Hydrology, Jalvigyan Bhawan, Roorkee 247667, India e-mail:
[email protected]
Abstract A survey of the River Kali in western Uttar Pradesh (India) has been carried out to assess the contribution of point and non-point sources of pollution to the river. The river shows strong seasonal dependence for various constituents and the water quality deteriorates sharply as it flows through Muzaffarnagar city. The important characteristic associated with the pollution of the river is the depletion of oxygen over a stretch of about 25 km. High values of BOD and COD indicate a high degree of organic pollution in the river. A chemical mass balance approach has been used for measuring changes in the concentration and/or load to the river, which develops an interesting concept to discriminate between point and non-point sources of pollution to the river. The resulting differential loadings, if adjusted for uncharacterized non-point contribution to the load, may represent the total point source load to the river minus any losses due to volatilization, settling, and/or degradation. Mass balance calculations conducted for certain water quality constituents indicated that additional inputs are needed to account for the observed differences in load along the river. The sources may include non-point sources of pollution due to agricultural activities, sediment remobilization or entrainment, groundwater intrusion or a combination of these sources. The difference may also be attributed to some point sources of pollution which could not be identified in the course of these investigations.
Evaluation de sources de pollutions ponctuelles et diffuses par une approche fondée sur un bilan chimique Résumé Un suivi de la Rivière Kali (Uttar Pradesh Occidental, Inde) a été mené en vue d'évaluer les apports à la rivière de sources de pollutions ponctuelles et diffuses. La rivière présente une forte variation saisonnière de certains composants et la qualité de la rivière se détériore brutalement au niveau de la ville de Muzaffarnagar. La caractéristique la plus importante de la pollution de la rivière est le déficit en oxygène le long d'un bief d'environ 25 km de long. Les fortes valeurs de la DBO et de la DCO indiquent une importante pollution organique de la rivière. Une approche fondée sur un bilan chimique en masse a été utilisée afin de mesurer les modifications des concentrations de la rivière et/ou des rejets qu'elle reçoit, ce qui constitue une intéressante possibilité de distinguer les sources de pollution ponctuelles et les sources de pollution diffuses. Les incréments de charge, s'ils résultent d'une source de pollution diffuse inconnue, représentent le rejet à la rivière diminué des pertes dues à l'évaporation, à la sédimentation et/ou à la dégradation. Les bilans chimiques réalisés pour certaines variables de la qualité des eaux ont montré que des apports supplémentaires étaient nécessaires pour rendre compte des différences de charge observées le long de la rivière. Ces apports peuvent être diffus, provenant des activités agricoles, de la remise en suspension des sédiments, de résurgences d'eaux souterraines ou d'une combinaison de tels apports. Les différences observées peuvent également être imputées à des sources ponctuelles qui n'avaient pas pu être identifiées dans le cadre de nos recherches.
Open for discussion until I December 1998
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INTRODUCTION The water of rivers and fresh water lakes plays an important role in overall development programmes of India, as a source of water supply for domestic and industrial purposes and also for agriculture, fishery and power development. However, the same water resources are also utilized for the disposal of industrial wastes and sewage, leading to water pollution. In western Uttar Pradesh most water resources are used for irrigation, fishing, to produce fish seed and fingerlings. These water resources are also utilized for the disposal of industrial wastes of more than 20 different industries (Verma et al., 1974; 1980; Verma & Dalela, 1975). The River Kali in western Uttar Pradesh is a typical receiving water for untreated municipal and industrial effluents. The river receives considerable amounts of waste every day from the industries and municipal area of Muzaffarnagar city. Agricultural waste is another factor contributing to pollution of the river water. The river has a significant socio-economic value to nearby areas, e.g. the river water is used for washing clothes, for recreation of domestic animals, as a carrier of municipal and industrial wastes, and in many cases water is drawn for agricultural uses as well (Ghosh et al., 1993). As such there is no pollution control measure for the river despite of such versatile social importance. The chemical characteristics of this river have been reported earlier with special reference to disposal of municipal and industrial waste (Jain, 1992, 1997). The river system contains many point and non-point sources of pollution. Monitoring of all such sources for all parameters everywhere is not possible. Besides, these are difficult and expensive to monitor and are subject to analytical errors. Indirect monitoring using upstream-downstream sampling sites, for measuring changes in the concentration and/or load to the river, provides an alternative means and is the main focus of this paper. In earlier papers, a mass balance approach (Jain, 1996) and adsorption characteristics of the bed sediments of the River Kali (Jain & Ram, 1997) have been discussed. The present paper describes mass balances of certain water quality constituents, viz., sodium, potassium, calcium, magnesium, chloride, sulphate, and phosphate for a 25 km long stretch of the river to assess the contribution of point and non-point sources of pollution to the river.
DESCRIPTION OF THE AREA The River Kali, in western Uttar Pradesh, is a small perennial river having a basin area of about 750 km2. The area under study is a part of the Indogangetic Plains, composed of Pleistocene and subrecent alluvium and lies between the latitude 29°33'N to 29°21'30"N and the longitude 77°43'E to 77°39'!5"E in the Muzaffarnagar district of Uttar Pradesh (Fig. 1). The climate of the area is characterized by a moderate type of subtropical monsoon. The average annual rainfall in the area is about 1000 mm, out of which the main part is received during the monsoon period. The major land use is agriculture and there is no effective forest cover. The soils of the area are loam to silty loam and are free of carbonates.
Assessment of point and non-point sources of pollution using chemical mass balance approach 381
—P9 25
-429*20
Fig. 1 The River Kali: (a) schematic representation of the system; (b) general plan of sampling locations.
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The river basin contains towns and villages surrounded by agricultural areas. The quantity and quality of river water are affected by discharge from municipal and industrial areas of Muzaffarnagar city as well as runoff from agricultural areas. POLLUTION SOURCES AND SAMPLING STATIONS The River Kali is subjected to a varying degree of pollution, caused by numerous outfalls of municipal and industrial effluents and by other human activities. The main sources which create pollution in the river include municipal waste of Muzaffarnagar city, waste from a variety of industries (such as steel, rubber, ceramic, chemical, plastic, dairy, pulp and paper, and laundries), and Mansurpur sugar mill and distillery waste. The composite waste from a variety of industries is transferred into the river through Muzaffarnagar's main drain. The major portion of the municipal waste water of Muzaffarnagar city flows through a system of open drains and is discharged into the river at two points. One of these points has mean discharge of about 0.3 m3 s"1 near the village of Nayajupura while the other point has almost the same flow downstream of the bridge on Muzaffarnagar-Shamli Road. At both points, numerous people and domestic animals (cows and buffaloes) bathe, and clothes washing activities are common just upstream of the outfalls for the municipal waste. From the point of view of river pollution and deterioration of water quality in the bathing areas, the discharge from these drains is most critical. A general plan of the sampling stations with respect to different outfalls of municipal and industrial wastes into the river is shown in Fig. 1. Six stations were selected for sampling: four close to the outfalls of waste disposals and one each at the upstream and downstream sections of the total reach of 25 km under study. These can be characterized as follows: Station I (upstream site) is located in the relatively unpolluted river water zone near the village of Malira and upstream of the discharge of municipal and industrial wastes into the river. At this point the high banks contain sandy soils. Station a (municipal waste) is located near the village of Nayajupura where a part of the municipal waste water of Muzaffarnagar city is discharged into the river. Station b (municipal waste) is downstream of a bridge over the MuzaffarnagarShamli Road. Station c (industrial drain) is located in the main Muzaffarnagar drain, downstream of the bridge near the village of Begharazpur, through which the mixed waste water from a variety of industries and municipal areas is discharged into the river. Station d (sugar mill drain) is located near the village of Mansurpur on the National Highway. Station II (downstream site) is situated near the village of Pur Balian on the Mansurpur-Shahpur Road about 4 km from the village Mansurpur, downstream of the outfall of sugar mill waste. The colour of the water at this point is black and the soil is sandy mixed with black organic material.
Assessment ofpoint and non-point sources ofpollution using chemical mass balance approach 383
METHODOLOGY Monthly samples of the river water and effluents were collected using a Hydro-Bios standard water sampler over a period of one year (January-December 1992) by the dip/grab sampling method. All the samples were collected from mid-stream at about 15 cm depth, and stored in pre-cleaned polyethylene bottles. Some parameters, such as temperature, pH, electrical conductance and turbidity were measured on the spot by means of portable meters (WTW, Germany). For other parameters, samples were preserved by adding an appropriate reagent (APHA, 1985). The samples so preserved were brought to the laboratory, in sampling kits maintained at 4°C, for detailed chemical analysis. The discharge at all six sampling sites was also determined during each visit using a Seba current meter by the area-velocity method. Physico-chemical analyses were conducted following standard methods (APHA, 1985). Chloride was determined by the argentometric method. Phosphate was estimated by stannous chloride method in the form of molybdenum blue, and sulphate by the turbidimetric method with barium chloride crystals. Sodium and potassium were determined by the flame-emission method using flame photometer model Toshniwal RL 01.02, while calcium and magnesium were determined using a Perkin-Elmer Atomic Absorption Spectrometer Model 3110 using air-acetylene flame.
RESULTS AND DISCUSSION Seasonal variations in the intensity of rainfall cause both quality and quantity of flow of the river to vary widely. During the wet season, the runoff conveys both suspended and dissolved matter into the river. The river has a maximum flow of 6.1 and 7.7 m3 s"1 in the wet season and a minimum flow of 3.3 and 5.0 m3 s"1 for dry weather at upstream and downstream sections, respectively. The increase in discharge between stations I and II (upstream and downstream sections of the reach under study) is due to the outfalls of municipal waste at Muzaffarnagar city, combined industrial waste through Muzaffarnagar main drain and Mansurpur sugar mill and distillery waste, in addition to the normal base flow. Effluent samples, collected from the municipal waste, combined industrial waste and sugar mill waste, were characterized for various water quality parameters and the results are discussed in an earlier paper (Jain, 1997).
Time series of water quality constituents The municipal waste water from Muzaffarnagar city, waste water from industrial complex and Mansurpur sugar mill constitute the major pollution inputs to the river and represent about 25% of the total discharge in the river. Time series of some water quality constituents at the upstream and downstream sections are shown in Fig. 2. It is clearly evident from the figures that there is a strong seasonal dependence among water quality constituents with elevated concentrations during dry summer and lower concentrations in monsoon periods. This is
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Discharge (m 3 s
Ma (mg I"1)
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-
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Fig. 2 Time series of discharge and water quality constituents at upstream and downstream sites.
due to the low flow in the river during dry summer months. During monsoon season, however, considerable dilution of the river water occurs due to runoff from the land as well as through direct channel precipitation. The water in the river is transparent
Assessment ofpoint and non-point sources ofpollution using chemical mass balance approach 385
in the upstream section while it is blackish in the downstream section due to the mixing of industrial waste waters. The sugar mill effluent stagnates in the drain and stream for a long time. Because of this, biological activity starts and obnoxious conditions soon develop in the region. These septic conditions result in the production of hydrogen sulphide gas imparting black colour to the effluent and the streamwater. The annual mean temperature was 23.8 and 25.6°C in the upstream and downstream sections, respectively, with a wide seasonal fluctuation (a difference of approx. 12°C was observed between maximum and minimum values at both places). The pH of the river water at both upstream and downstream sections was always found to be towards the alkaline side. Slightly lower values of pH were observed in the downstream section due to the mixing of sugar mill waste which is acidic in nature. The maximum conductivity values were obtained during pre-monsoon months due to a decrease in freshwater inflows and relatively large contribution from groundwater inflows and waste discharges to the overall flows in the river. However, conductivity values seldom exceeded 1000 /xS off1. The dissolved oxygen condition in the upstream section was quite satisfactory (7.0-7.7 mg l"1), but a critical situation was observed in the downstream section (2.1-3.0 mg l"1). The sudden drop in dissolved oxygen (DO) and abrupt rise in BOD in the downstream section is attributed to the discharge of untreated municipal and industrial wastes in the river. It may be stated that the maximum value of BOD for potable water is 2 mg l"1 and that for bathing it is 3 mg l"1. The higher values of BOD and COD observed both in the upstream and downstream sections indicate a high degree of organic pollution rendering the water unsuitable for domestic purposes. From the general distribution of DO and oxygen consumed from station I (upstream) and station II (downstream), it appears that the wastes discharged into the river are being oxidized and the rate of oxygen replenishment in the water is lower than the oxygen utilization. This is clearly evident from the depletion of oxygen between station I and station II. Deoxygenation generally occurs as a result of breakdown of organic matter by bacterial activity and therefore the discharge of municipal and industrial wastes into the river at regular intervals does not allow any self-purification to occur. The average sulphate concentration of the river water was 18.7 and 31 mg l"1 in the upstream and downstream sections, respectively. The increase in concentration in the downstream section may be due to influx of sewage and waste effluents. Channel precipitation and runoff waters from agricultural lands may also contribute to the overall sulphate content in the river water. The average concentration of phosphate in the river water was found to be 0.22 and 0.51 mg l'1 in the upstream and downstream. sections, respectively and the monthly variations are shown in Fig. 2. The average concentration of sodium in the downstream section was 49.2 mg l"1, with a maximum value of 62 mg Î 1 and a minimum value of 41 mg l"1. The increase in sodium content in the downstream section may be attributed to the contribution from sewage and other waste effluents entering the river. The limit for sodium in potable waters is determined by threshold taste considerations and not due to any toxic effects for normal healthy humans. Waters with Na concentrations of 200 mg l"1
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are quite acceptable (WHO, 1984). The average potassium content in the upstream section was 5.0 mg l"1 while in the downstream section it was 19.8 mg l1. This increase in potassium content may be attributed to contributions of runoff from agricultural lands (potassic fertilizers) and waste effluents. The average calcium and magnesium contents in the upstream and downstream sections of River Kali were within normal ranges. The above observations clearly indicate that the river is severely polluted. The colour of the water is blackish in the downstream section and it emits an unpleasant odour. The lower values of dissolved oxygen and higher values of BOD and COD clearly indicate a high degree of organic pollution in the river.
Indirect measurement of point sources using upstream-downstream river water quality data If one is interested in information on constituents from individual sources, then indirect measurement of the sum of the sources is possible in the receiving water using the following equation:
QDcD - QvCu = i l , where QD and Qv are downstream and upstream flows, CD and Cv are the downI!
stream and upstream concentrations in the river water, and ^jLi is the sum of all individual loadings to the river. This equation represents the mass budget and can be used to determine a much more accurate estimate of 2_,L,- than that likely to be obtained from summing the individual loadings. Here, the /^L,- term is not only the sum of loadings entering the receiving water body, but rather the net effect of the loadings plus any loss or generation within the water body. For any contaminant that undergoes significant volatilization or degradation, this approach will not give an accurate loading summation unless the time of travel between downstream and upstream is small compared to the rate constants for losses. The same is true for substances that settle from the water column. The above mentioned indirect approach has been successfully utilized in the present study to assess the contribution of point and non-point sources of pollution to the river and the results have been presented in Fig. 3. This approach is useful for measuring the changes in the differential concentration and/or load to the river from year to year (Dolan & El-Shaarawi, 1989). The upstream-downstream approach is very useful when the difference in the concentration and/or load is of interest.
Assessment of point and non-point sources of pollution using chemical mass balance approach 387
35 30
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Downstream site Differential loading
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0)
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Municipal waste a 14 4
Municipal waste b Industrial drain
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Ca
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Fig. 4 Point source loadings of various constituents.
Mass balance to upstream-downstream river water quality data The loadings of various constituents for the major outfalls that enter the River Kali are presented in Fig. 4. The estimated differential loadings for the various water
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quality constituents compare favourably with point source loadings of the corresponding constituent, considering that the latter does not take into account uncharacterized non-point sources of pollution. Therefore, it can be argued that the difference in loadings may be due mainly to the contribution of non-point sources of pollution resulting from agricultural activities, groundwater intrusion and/or sediment-water interactions. Similar conclusions were drawn by Latimer et al. (1988) for the increase of some metal ion concentrations in the downstream section of the River Pawtuxet. Berndtsson (1990) also established water budgets and chemical mass balance of some constituents for a small reach of the River Hoje and reported that half of the transported zinc is retained in the stream sediments. The mass balance for various constituents for the River Kali are shown in Fig. 5. It is inferred from the results that additional inputs are needed to account for observed difference in load along the river. The sources may include non-point sources of pollution due to agricultural activities, remobilization from or entrainment of contaminated bottom sediments, groundwater intrusion or a combination of these sources. The difference may also be attributed to some small point sources of pollution which could not be identified in the course of present investigations. The analysis of suspended and bed sediment samples (though not attempted in the present investigations) can provide valuable information regarding the observed differences in the concentration and/or load to the river (Berndtsson, 1990). The analysis of sediments permits us to detect pollution that could escape water analysis, and also provides information about the critical sites of the water system under consideration (Fôrstner & Salomons, 1980). They are the important vectors for the transport of contaminants in river systems (Allen, 1986; Ongley et al., 1988). Sakai et al. (1986) and Tarashima & Tsukamoto (1980) studied the mechanism of
Upstream site Municipal waste a §g; Municipal waste b Industrial drain . Sugar mill drain Downstream site
Na
K Ca Mg CI S04 Fig. 5 Loadings and mass balance for various constituents.
Assessment of point and non-point sources of pollution using chemical mass balance approach 389
distribution and transport of pollutants in aquatic systems. Grain size is often considered to be one of the most important factors in controlling the retention of heavy metals (Horowitz, 1988; Combest, 1991). Recently, Bertin & Bourg (1995) performed a geochemical and granulometric analysis of sediments from the Lot River basin to investigate the factors controlling heavy metal retention in sediments and reported that transport of metal ions takes place mainly in particulate form. Accordingly, further studies have been planned on water and sediment samples of the River Kali to substantiate the findings of the present study.
CONCLUSIONS From the study conducted on the River Kali, it is concluded that the quality of the river deteriorates considerably as a result of pollutants discharged into the river from municipal and industrial activities in the region. The discharge of municipal and industrial wastes into the river at regular intervals does not allow any self purification to occur. The high values of BOD and COD are of main concern and the sources of such pollution need urgent control. Therefore, as a measure of conserving the aquatic life, it is desirable that before discharging wastes into the river, these should be suitably treated either chemically or biologically to an adequate extent. The paper also provides an account of the advantages of using upstreamdownstream river water quality data to estimate the load to the river and to detect changes in water quality constituents within the river system. Comparisons between upstream and downstream monitoring sites reveal changes in the concentration and/or load of pollutants and can be used to discriminate between point and non-point sources of pollution to the river. Indirect monitoring of point sources using upstream-downstream sampling locations provides a better alternative for a systematic study over other conventional techniques.
REFERENCES Allen, R. J. (1986) The role of particulate matter in the fate of contaminants in aquatic ecosystem. Inland Waters Directorate, Scientific Series no. 142, National Water Research Institute, Canada Centre for Inland Waters, Burlington, Ontario, Canada. APHA (American Public Health Association) (1985) Standard Methods for the Examination of Water and Wastewater (sixteenth edn). American Public Health Association, New York. Berndtsson, R. (1990) Transport and sedimentation of pollutants in a river reach: a chemical mass balance approach. Wat. Resour. Res. 26(7), 1549-1558. Bertin, C. & Bourg, A. C. M. (1995) Trends in the heavy metal content (Cd, Pb, Zn) of river sediments in the drainage basin of smelting activities. Wat. Res. 29(7), 1729-1736. Combest, K. B. (1991) Trace metals in sediment: spatial trends and sorption processes. Wat. Resour. Bull. 27, 19-28. Dolan, D. M. & El-Shaarawi, A. H. (1989) Inferences about point source loadings from upstream-downstream river monitoring data. Environ. Monitoring and Assessment 12, 343-357. Forstner, U. & Salomons, W. (1980) Trace metal analysis on polluted sediments. Part I: assessment of sources and intensities. Environ. Technol. Lett. 1, 494-505. Ghosh, N. C , Jain, C. K. & Tyagi, A. (1993) Some issues of water quality monitoring. Asian Environment 15(2), 7891. Horowitz, A. J. (1988) A review of physical and chemical partitioning of inorganic constituents in sediments. In: The Role of Sediments in the Chemistry of Aquatic Systems (Proc. Sediment Chemistry Workshop) (ed. by A. J. Horowitz & W. L. Bradford), 7-22. US Geological Survey Circular no. 969.
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Jain, C. K. (1992) Effect of waste disposals on quality of water of River Kali (Uttar Pradesh). Techn. Report no. TR148, National Institute of Hydrology, Roorkee, India. Jain, C. K. (1996) Application of chemical mass balance approach to upstream-downstream river monitoring data. J. Hydrol. 182, 105-115. Jain, C. K. & Ram, D. (1997) Adsorption of lead and zinc on bed sediments of the River Kali. Wat. Res. 31(1), 154162. Jain, C. K., Bhatia, K. K. S. & Seth, S. M. (1997) Characterization of waste disposals and their impact on water quality of River Kali, Uttar Pradesh. Indian J. Environ. Prot. 17(4), 287-295. Latimer, J. S., Carey, C. G., Hoffman, E. J. & Quinn, J. G. (1988) Water quality in the Pawtuxet River: metal monitoring and geochemistry. Wat. Resour. Bull. 24(4), 791-800. Ongley, E. D., Birkholz, D. A., Carey, J. H. & Samoiloff, M. R. (1988) Is water a relevant sampling medium for toxic chemicals? An alternative environmental sensing strategy. /. Environ. Qual. 17, 391-401. Sakai, H., Kojima, Y. & Saito, K. (1986) Distribution of heavy metals in water and sieved sediments in the Toyohira River. Wat. Res. 20(5), 559-567. Tarashima, Y. & Tsukamoto, M. (1980) Study on the mechanism of distribution and transport of trace adsorptive pollutants in a river, II. concentration changes of dissolved and particulate metal in river flow. Environ. Consent. Engng 9, 435-445. Verma, S. R. & Dalela, R. C. (1975) Studies on the pollution of the Kalinadi by industrial wastes near Mansurpur, Parts I and II. Acta Hydrochim. Hydrobiol. 3(3), 239-274. Verma, S. R., Dalela, R. C , Tyagi, M. P. & Gupta, S. P. (1974) Studies on the characteristics and disposal problems of the industrial effluents with reference to ISI standards: Part I. Indian J. Environ. Health 16, 289-299. Verma, S. R., Shukla, G. R. & Dalela, R. C. (1980) Studies on the pollution of Hindon River in relation to fish and fisheries. Limnologica 12, 33-75. WHO (1984) Guidelines for Drinking Water Quality (vol. 1): Recommendations, 1-130. World Health Organization, Geneva. Received 7 March 1997; accepted 23 September 1997
