The microbial quality of water from Sasthamcotta Lake in Kollam District is found to be safe and within the limits of drinking water standards set by the Central Pollution Control Board (CPCB), revealed in a study conducted by CIFT scientists in January 2022. The study team was led by Principal Scientist and Head, Microbiology, Fermentation and Biotechnology division, Dr. Toms C Joseph and included scientists Dr. Murugadas S, Dr. V. Visnuvinayagam, and Radhakrishnan Nair V. has carried out the microbiological testing of water samples collected from various places of the lake. Sasthamcotta Lake in Kollam District is the largest freshwater Lake in Kerala State which is spring fed and is also a Ramsar notified site. The Lake is a source of drinking water for more than half a million people in the Kollam District. The study is very encouraging as due to rapid urbanization, industrialization and environmental degradation, the water quality of surface water of most of the freshwater lakes around the world has deteriorated. Moreover, anthropogenic discharges like domestic sewage can make the water unsuitable for drinking.
Microbiological limits are set for water meant for drinking purpose by the Central Pollution Control Board (CPCB) in India. The microbiological quality of water is based on the presence of indicator bacteria. Generally, coliforms and in particular E. coli or thermo tolerant coliforms, found in the human and animal intestine, are considered as indicator organisms. Water is designated for a particular use based on the water quality parameters and are categorised from A to E. Water belonging to category A can be used for drinking without conventional treatment but with disinfection. The study revealed that microbiological water quality for indicator bacteria (coliform bacteria) in Sasthamcotta Lake at all the locations studied were within the limit of ≤50 Most Probable Number (MPN) coliform in 100mL set for class A type of water. As per the European Union (EU) standards, the water can be rated as Excellent Quality (E. coli <500 colony forming unit (cfu)/100mL).
Leela Edwin, Director of ICAR-CIFT opined that even though the survey revealed excellent microbiological quality of water from Sasthamcotta Lake, there is a need for continuous monitoring to initiate remedial measures if there is drop in the quality of water.