No abstract

The Meenachil, the only river that flows through the heart of the Kottayam district of Kerala state, India was selected for the study. The present study has been carried out with an objective to systematically examine the prevalence of indicator and pathogenic microorganisms and to compare the microbiological quality of the river water during the pre-monsoon and post-monsoon seasons. Water samples from 44 different sites during pre-monsoon and post-monsoon seasons were collected for the analysis. During the pre-monsoon period, the faecal coliform count ranged from 230 to 110,000 MPN/100 ml while there was a variation from 200 to 4600 MPN/100 ml during the postmonsoon period. When the faecal streptococci count was analysed, it ranged from 140 to 110,000 MPN/100 ml during the pre-monsoon and 70 to 4600 MPN/100 ml during the post-monsoon seasons, respectively. All the samples collected were found to have total viable count (TVC) higher than those prescribed by Bureau of Indian Standards (ISI 1991). Total viable counts were found in the range of 1.1 9 102 to 32 9 102 cfu/ml in the pre-monsoon and 1.0 9 102 to 26 9 102 cfu/ml in the post-monsoon. The presence of faecal indicator bacteria, Escherichia coli and potentially pathogenic bacteria, Vibrio cholerae, Vibrio parahaemolyticus and Salmonella enterica in the Meenachil River indicates that the bacteriological quality of the Meenachil River is poor. Moreover, it sheds light to the fact that raw sewage is being dumped into the Meenachil River. Urban runoffs and effluents of rubber factories appear to be the important sources of faecal contamination in the river. From this study, we conclude that these water bodies pose significant public health hazards. Adequate sanitary infrastructure will help in preventing source water contamination. Besides this, public health education aimed at improving personal, household and community hygiene is urgent.

The present work aimed to evaluate the riparian species diversity of five subwatersheds of the Meenachil river basin (1208.1 km 2 ) and to compare that with the main river channel. A total of 441 species were recorded belonging to 106 families. The Leguminosae was represented by the highest number of species (39 spp.) followed by Poaceae (25 spp.). The quantitative features such as density and importance value index of species varied greatly. In the present study, the diversity index of shrubs and herbs was found to be higher than the tree species. The concentration of dominance was recorded highest in the tree species. Shannon-Wiener index (H 0 ) ranged from 1.0 to 2.95. The Margalef's species richness index varied from 2.43 to 6.69, equitability or evenness index varied from 0.62 to 1.42, the species heterogeneity index varied from 0.4 to 0.83, and Mc Intosh diversity index varied from 56.57 to 329.27. A greater number of tree species fell in 41-60 cm girth at breast height, but less number of tree individuals is represented in above 100-cm diameter class.