MICROBIAL POLLUTION STUDIES OF RIVER YAMUNA AT DELHI

Abstract

This study addresses to the microbiological pollution of river Yamuna in Delhi Segment flow. The river Yamuna is a large Himalayan river, with total length of 1376 km, from Yamunotri to Sangam at Allahabad. It travels through historic cities of northern India where this river is polluted by point sources of discharges, mainly domestic sewage and mixed sewage (industrial + domestic) discharges in some places. Delhi, the capital of India, alone contributes around 3296 MLD of sewage by virtue of drains ouffalling in Yamuna. This is more than all the class 11 cities of India put together. The river Yamuna, through Delhi segment, has a lean discharge of 600 MLD and maximum discharge of 23,350 MLD, providing dilution ratio of 0.18 and 7.08 respectively. On the basis of Hydrological, geological, ecological characteristics and presence of three barrages, the river can be divided into five different segments viz. i) Himalayan segment, from origin to the Tajewala barrage (172 km), ii) Upper segment, from the Tajewala barrage to the Wazirabad barrage (224 km), iii) The Delhi segment, from the Wazirabad barrage to the Okhala barrage (22 km), Iv) Eutrophicated segment, from the Okhla barrage to the confluence of the river Chambal (490 km), v) Diluted segment, from confluence of the Chambal to the confluence with the river Ganges (468 km). The river Yamuna is extensively used for abstractive and instream purposes. Traditionally, the pollution content of river Yamuna at Delhi has been extensively studied with regard to physical and chemical characteristics. However, lately microbiological quality of the Yamuna river has come under greater focus as it is a direct measurement of deleterious effects of pollution on human health. Further, the maximum affects come up during lean seasons, when the dilution capacities are lowest during the year. The pollutional aspects of river Yamuna at Delhi during lean period were studied through significant contaminating indicators viz. Heterotrophic plate count (Total plate count, CFU per ml), Total coliform (MPN / 100m1), Fecal coliform (MPN / 100m1), Helminths (eggs! liter), Coliphages per 100m1, and also related parameters viz Dissolved Oxygen (ppm), Biochemical Oxygen iii Demand (ppm), Chemical Oxygen Demand (ppm), pH, Temperature (C), Total Dissolved Solids (ppm) and Turbidity (NTU) as per standard methods. Six sampling locations (Bridge Sites) were selected and Four set of samples were collected over a period of Four months from March 2004 to June 2004. Results obtained showed that the minimum and maximum values with regard to all the sampling points investigated were 2.4E +03 CFU/mI and 1.5E +06 CFU/ml for Total Plate Count, 2.1E +04 MPN/100m1 and 4.3E +07 MPN/100m1 for Total coliforms, 2.1E +03 MPN/100m1 and 3.9E +07 MPN/100m1 for Fecal Coliforms, 5.28E +03 per ml and 9.0E +08 per ml for Coliphages, 5 Eggs/1 and 38 Eggs/I for Helminths, 0.0 mg/I and 8.0 mg/I for Dissolved oxygen, 3 mg/I and 52 mg/I for Biochemical oxygen demand and 6 mg/I and 120 mg/I for Chemical oxygen demand. The observed values indicate that the water is not suitable even for the lowest quality DBU with respect to the microbial quality, without minor or major treatment. Also the BOD values in river Yamuna Delhi segment are also found frequently exceeding the permissible limit of '3 mg/I or less' for DBU class B and class C i.e. for outdoor bathing and for Drinking water source after conventional treatment and disinfection respectively. This study has carried out detailed microbial quality estimation with the aims to investigate the inter relationship between various microbial indicators viz. HPC and TC versus FC values in river Yamuna Delhi segment. The relationships found are: (i) FC, MPN /100m1 = 0.0232 X (TC, MPN/100m1) 1.1697 (ii) FC, MPN /100m1 = 0.0326 X (HPC /ml) 1.4742 The relationships have been found with high degree of Correlation. Thus the results of Fecal coliform, MPN/ 100m1, obtained by laboratory analysis, can be verified by the above equations. The inter relationship between BOD and COD values in river stretch, under study, was also evaluated. Also COD test gives a relatively quicker estimation of the carbonaceous contents of the sample compared to the BOD test. Relationship investigated BOD = 0.454 X COD will be useful for approximate rapid water quality estimations. This rapid system of measurement of Yamuna water quality through FC and COD will go a long way in handling water treatment efficiency at the water treatment plant as well as Sewage Treatment Plants installed in Delhi.