Seasonal and Temporal Variations in Physico-chemical and Bacteriological Characteristics of River Ganga in Varanasi

Various physico chemical characteristics of the river Ganga in Varanasi were studied in the Oct 2005 to Nov 2006. Ecological parameters like dissolved oxygen(DO), pH, nitrate(NO₃^-),PO₄^3- and bacterial population were analyzed and compared with standard permissible limits to assess the best designated use of the river water for various purposes. Study revealed that the water quality at Varanasi was not safe for human use. Result shows that Fecal coliform (20.9×10³/ 100mL), Fecal streptococci (93/100mL), Total bacterial density (1.43×10³/L), Total coliform (25.4×10³/100mL) Escherichia coli (6.9×10³/100mL) and Clostridium perfringens (396/100mL ) were substantially high and much beyond the permissible limit of ISI and WHO. There were a marked correlation observed between physico-chemical quality of water and bacterial density. Some pathogenic bacteria Actinomyces sp., Aerobacter aerogenes, A. Cloacae, Micrococcus sp., Salmonella sp., Staphylococcus aureus, Bacillus sp. and Shigella sp., that indicate the higher level of fecal contamination in water. These untreated water sources are used for drinking and domestic purposes and pose a serious threat to the health of the consumers and therefore calls for urgent intervention by government.