Periodicity of coliform bacteria in an aquatic environment

The present study deals with enumeration and seasonal distribution of total and faecal coliform bacteria, the indicators of microorganisms causing faecal pollution of the aquatic ecosystem by a multiple tube technique. A lake called Upvan lake of Thane city, India was investigated during 1996-97 for the purpose. Bacterial population varied with seasonal variations in the water body. Bacterial counts increased during summer months and lowered during winter months. Highest coliform counts were reported in monsoon and lowest in winter season. Samples collected from different sites of the lake showed wide variations in the counts of bacteria. Positive correlation was established between faecal and total coliform. Bacteriological analysis of lake water indicated that water was polluted by faecal contaminants to the extent that it was unportable for drinking purposes and unsuitable from the recreation point of view and hence needed thorough impoundment. (C) 1999 Published by Elsevier Science Ltd on behalf of the IAWQ. All rights reserved.