Abstract

Total coliform count is commonly used to assess contamination level of drinking and swimming waters, especially with pathogenic bacteria of intestinal origin. The common sources of coliforms in Kashmir Himalayan lakes include point source discharges (raw sewage, combined sewer overflows, effluents from wastewater treatment plants, industrial sources) and non-point source discharges (agriculture, forestry and urban run-off). In the present study, total coliforms were enumerated using a multiple tube fermentation technique with lactose broth as the presumptive medium, eosine-methylene-blue (EMB) agar medium as the confirmatory medium and brilliant green bile broth for completed test. All the samples obtained from the lake were positive with respect to the coliform occurrence, though the count was variable ranging between 4 and 460 MPN/100 ml. Highest proportion of indicator coliforms was found in the water samples collected at the site surrounded by residential hamlets (site II) in comparison to the other three sites. The results allow us to conclude that none of the studied water samples was fit for drinking in view of high coliform count, though most of the water samples (95%) obtained from the lake with a good or fair quality could be used for bathing and swimming. These results have important implications for lake managers and local inhabitants that use the water of this lake for various purposes.

Key words: Total coliform, bacteria, Manasbal Lake, Himalaya.