Immersion of thousands of Ganesha idols by residents, along with other things, has increased the turbidity levels in prominent lakes in the city, according to an on-site water analysis conducted by the Indian Water Works Association as part of the World Water Quality Monitoring Programme-2012.
The Association took water samples from various water bodies around the city on Wednesday and carried out tests in mobile laboratories to determine its quality and potability.
Accordingly, the Madiwala and Yediyur lakes were found to be the most polluted with low dissolved oxygen levels.
The turbidity levels were two to five times than the permitted values in these tanks. The permissible level of turbidity (muddiness created by suspended foreign particles) is 10. The Madiwala Lake has a turbidity level of 50 and the Yediyur Lake water has 20.
The reason for high turbidity, according to the report, is the high quantity of immersion of Ganesha idols, effluents’ discharge from surrounding areas and raw sewage. Consequently, there is an increase in the pollution levels of these lakes and it may contaminate water in areas located downstream.
Among the many findings, the preliminary study also presented a report which indicated that the levels of Dissolved Oxygen (DO) is also far below the safe limits in both these lakes.
The Yediyur Lake with a DO level of 5.0 and Madiwala Lake with a DO level of 4.0 are far below the allowed range of 6.5-8, the study pointed out.
H K Ramaraju, Joint Director of the Indian Water Works Association (IWWA) who is also the Regional Coordinator (South) of the World Water Quality Monitoring Programme 2012, said that a low DO level would lead to the death of aquatic animals.
Efforts taken to create awareness among public have failed, admitted Dr Vaman Acharya, Chairman, Karnataka State Pollution Control Board (KSPCB).
“Ninety per cent of the Ganesha idols have ended up in our lakes. With the Plaster of Paris, garlands and clay, the water at the surface and bottom levels have to be desilted,” he said. “It is very difficult to actually make a law as there is absolutely no compliance from the people. Desiltation process would take a long time.”
Dr Vijayashree of the Institute of Public Health said, “Turbid water has organic materials which rapidly decompose and they may have effects on skin and when consumed, they lead to gastroenteritis.”
Y N Ashwath, Chairman of the BBMP’s Standing Committee on Horticulture , said that these lakes will be desilted and cleaned within three days.