Hydrology and Assessment of Lotic Water Quality in Cuttack City, India

HYDROLOGY AND ASSESSMENT OF LOTIC WATER QUALITY IN CUTTACK CITY, INDIA J. DAS and B. C. ACHARYA∗ Mineralogy and Metallography Department, Regional Research Laboratory, Bhubaneswar (CSIR), India ∗ ( author for correspondence, e-mail: [email protected]) (Received 1 February 2002; accepted 6 June 2003) Abstract. A total of 120 water and sewage samples were collected from 20 stations over six con- secutive seasons in two years in order to study the possible impact of domestic sewage on the lotic water in and around Cuttack, India. A majority of samples exceeded the maximum permissible limit + − set by WHO for NH4 and NO3 contents. Total viable count (TVC) and Escherichia coli (E. coli) counts in all the samples were high and the waters were not potable. The nutrient characteristics of the study area exhibited drastic temporal variation indicating highest concentration during the summer season compared to winter and rains. The persistence of dissolved oxygen (DO) deficit and very high biochemical oxygen demands (BOD) all along the water courses suggest that the deoxygenation rate of lotic water was much higher than reoxygenation. Hierarchical cluster analysis of the various physico-chemical and microbial parameters established three different zones and the most contaminated zone was found to be near the domestic sewage mixing points. Keywords: nutrients, pollution, sewage, water 1. Introduction Surface water resources have played an important role throughout history in the development of human civilization. About one third of the drinking water require- ment of the world is obtained from surface sources like rivers, canals and lakes. But, these sources serve as the best sinks for the discharge of domestic as well as industrial wastes. This unscientific disposal of wastes has caused immense prob- lems not only to human beings but also to the aquatic environment world wide. In India, this problem started long back but intensified during the last few decades and now the situation has become alarming. Consequently, studies on the major river ecosystems indicate that the major Indian rivers are grossly polluted, espe- cially beside the cities (Upadhyaya et al., 1982; Srivastava, 1992). Potability of the lotic water bodies in and around Cuttack, a major city in eastern India, has not been established, though huge domestic effluents generated have been discharged untreated over the years. Hence, an investigation was carried out to examine the water quality through various physico-chemical and microbiological parameters, and to determine the Water, Air, and Soil Pollution 150: 163–175, 2003. © 2003 Kluwer Academic Publishers. Printed in the Netherlands. 164 J. DAS AND B. C. ACHARYA Figure 1. Location map showing the sampling stations of the study area. factors contributing to the pollution load of the lotic water bodies in and around Cuttack. 2. Materials and Methods 2.1. STUDY AREA Cuttack city (20◦2602 to 20◦2955N, 85◦4820 to 85◦5630E) is surrounded by river Mahanadi and its tributary Kathajodi and the city is elongated in east-west direction. The annual flow of the Mahanadi is 66 640 × 106 m3, but accounted for about 75% during monsoon period (Das and Sahoo, 1996). The flow of the river Kathajodi also reaches the peak during the rains. The width and volume in the flow decrease to a great extent during rest of the year, particularly during summer months. Besides the rivers, Taladanda canal originating at a barrage on Mahanadi, passes through the city in an east-west direction and serves as a source of water for the residents. The flow of the canal is fully controlled by the barrage, but maximum flow occurs during rainy season. River Kathajodi receives raw domestic sewage from the city, at two points, viz. Khannagar and Mattagajapur. Sometimes during summer, water of the river Kathajodi becomes black near the discharge points. HYDROLOGY AND ASSESSMENT OF LOTIC WATER QUALITY IN INDIA 165 Similarly, the Mahanadi receives a part of the sewage near station 11 (Figure 1), but the volume is much less than the amount of run-off. The Taladanda canal is also not free from pollution load put in by the residents of the city. The danger- ous and infectious wastes produced by the S.C.B. Medical college and hospital, organic garbage from the nearby vegetable godowns and markets find their way to the canal. The presence of a number of dairy farms and high density of human population along the canal add more waste products in the form of animal and human excreta to the water of the canal. 2.2. SAMPLING AND PRESERVATION Water samples were collected from 17 stations located along Mahanadi, Kathajodi rivers and Taladanda canal during different seasons (winter, summer and rainy) over a period of two years from 1996 to 1997. The stations include upstream and downstream of sewage discharge points of the rivers and the canal (Figure 1). Sewage samples were also collected at 3 stations along the sewerage during the time of water sampling. Surface water samples were collected about 10 cm below the water surface using a glass bottle. Standard procedures were followed for the collection of water samples for chemical (Laxen and Harrison, 1981) and biolo- gical (APHA, 1985) analysis. Since the BOD of a number of samples exceeded the concentration of DO, the samples with an expected high BOD were diluted before incubation. The samples for physico-chemical analysis were kept in an ice box and transported to the laboratory for immediate analysis. 2.3. ANALYTICAL METHODS The temperature and pH of water samples were measured in the field. Samples were subjected to filtration prior to chemical analysis. The TDS was determined by a gravimetric process. The determination of sulphate was also done by a gravimetric process as described by Vogel (1968). The argentometric titration method was adopted for the determination of Cl−, while the total hardness was carried out by EDTA complexometric titration method, (APHA, 1976). The Winkler’s method was followed for the analysis of DO and BOD. Nitrate and ammonium were determined by colorimetric procedure. The TVC (total viable count) was determined by pour plate procedure by incubating at 28 ◦C in nutrient agar for 24 hr. The pour plating method using Mac Conkey agar, incubating at 37 ◦C for 24 hr was taken up to check the lactose positive organisms. Plating on Eosin-Methylene-Blue agar at 37 ◦C for 24 hr has given rise to E. coli counts. 166 J. DAS AND B. C. ACHARYA TABLE I Physico-chemical and microbial characteristics of raw sewage (mean values of 3 samples) Parameters Winter S.D.a Summer S.D.a Rainy S.D.a Temperature 24.0 0.5 31.3 0.7 27.1 0.5 pH 7.4 0.1 7.5 0.1 7.0 0.1 DS (mg/L) 1564.0 129.9 1486.0 56.4 1281.0 58.0 + NH4 (mg/L) 5.5 1.1 11.6 1.0 4.4 1.0 − NO3 (mg/L) 173.0 6.1 130.0 5.0 155.0 9.0 2− SO4 (mg/L) 122.0 21.6 103.0 18.9 116.0 11.2 Total hardness (mg/L) 225.0 28.2 207.0 23.5 140.0 8.7 − Cl (mg/L) 294.0 10.5 311.0 19.3 199.0 6.6 D.O. (mg/L) 0.5 0.0 0.1 0.1 1.0 0.1 B.O.D. (mg/L) 357.0 44.1 466.0 26.5 247.0 14.2 T.V.C. (million/100 ml) 954.0 63.5 3320.0 400.0 2246.0 104.1 E. coli (thousands/ml) 0.2 0.1 1.0 0.3 0.7 0.2 a S.D. = standard deviation. 3. Results and Discussion 3.1. RAW SEWAGE The mean values for the physico-chemical and microbial characteristics of the three stations of sewerage are presented seasonally (Table I). This showed very high concentrations of different ions, TDS, TVC and E. coli count. The lowest value was observed in the rainy season as a result of dilution of components by + − − rain water. High concentrations of NH4 ,NO3 ,Cl and heavy depletion of DO with increase in the BOD values (Dhillon et al., 1997) were observed throughout the study period. Some of the parameters like NH+,Cl− and BOD registered 4 − maximum values during summer while minimum values were obtained for NO3 2− and SO4 . Concentration of the ions did not vary much along the length of the sewerage. Presence of biodegradable organic matter and utilization of DO by micro and macro fauna could be the reasons for such low content of DO and very high BOD in the sewerage of Cuttack. − + − 3− Raw sewage contained excess concentrations of Cl ,NH4 ,NO3 ,PO4 ,and 2− SO4 as reported earlier by several authors (Hegde et al., 1992; Behnke, 1975; Tryon, 1976). It has been estimated that human excreta adds about 5 kg of nitrogen per person per annum to the environment (WHO, 1984). Addition of various biolo- gical wastes like septic tank effluent, dung and urine from the dairies to the sewerage may be the major cause of high concentration of the ions observed throughout HYDROLOGY AND ASSESSMENT OF LOTIC WATER QUALITY IN INDIA 167 − + the study period in Cuttack. In the aquatic environment reduction of NO3 to NH4 starts when the DO level goes below 0.4 ppm (Ghose and Sharma, 1992). During summer the reduction of NO− to NH+ under anaerobic condition and decreased 3 4 + − water input could be the reasons for the highest NH4 and lowest NO3 concentra- 2− tions in the sewage. Due to the same anoxic condition, the decomposition of SO4 by anaerobic bacteria might have taken place resulting in minimum values during the summer.

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