Archives

Page No. : 11-15

ABSTRACT

The study was conducted in 80 households with wells in villages of Thrissur district, Kerala during monsoon season. The wells were shallow type and were dug with an average depth of 10 m. Most of the wells lacked an adequate platform, drain or covering. The distance of wells from various pollution sources was measured and analyzed for their contribution to microbial contamination. It was observed that public was aware of water related diseases but disinfection was practiced only in 52.5% of households. Microbiological analyses revealed mean total viable count (TVC) was 3.38 ± 0.073 log10 cfu/ml and coliform count (CC), E. coli counts (ECC), faecal streptococcal count (FSC) and sulphite reducing clostridium counts of 11.57 ± 2.84, 2.01 ± 0.36, 14.56 ± 6.07, 1.64 ± 0.51 cfu/ml, respectively. Contamination of well water with at least one count per ml of indicator organisms like E. coli, faecal streptococcal and sulfite reducing Clostridium were found to be 31.25%, 55%, and 25%, respectively. Only 52.5% and 68.7% samples of well water met the WHO standards for coliforms and E. coli. Multiple linear regression analysis to measure the correlation of various independent variables (probable sources of pollution of wells) on the TVC, CC, ECC, FSC and sulphite reducing Clostridium counts revealed that the type of well was positively correlated with ECC by 0.405 and CC by 0.26. Depth of well was found to influence TVC and CC and a positive correlation of 0.320 and 0.284, respectively, was observed. Presence of human activity near the well was related to E. coli count (r=0.234). Distance of well from polluting sources such as latrines, cattle shed, manure pit, etc., were found to be negatively correlated with all the microbial counts and as the distance increased there was corresponding reduction in counts.

Keywords: Coliforms, E. coli, microbial contamination, sulphite reducing Clostridium