Investigations by the State Pollution Control Board (PCB) have revealed heavy pollution of wells at select locations in Ernakulam district.

The monitoring agency found that the total coliform (bacteria) count exceeded the permissible limits at various sites. The wells identified for the water quality monitoring programme were located at Vyttila, Edayar, Brahmapuram, Eloor and Kalamassery.

Tests showed that the well located near the solid waste treatment plant of the Kochi Corporation at Brahmapuram was heavily polluted. Continuous monitoring from January to December 2010 found that the maximum total coliform count recorded was 500 per 100 ml against the permissible limit of 50. The faecal count was 130 per 100 ml. Total coliform count is a general indicator of the water quality level.

According to the Pollution Control Board, the well at Brahmapuram is under class ‘A' (drinking water source without any conventional treatment but after disinfection) where the maximum total coliform count should be 50. The total coliform level at Eloor was 100 times beyond the permissible limit. Tests found that the maximum count was 5,000 per 100 ml at the well located near Eloor panchayat. The faecal coliform count here was 2,200. The total coliform count in the wells located at Edayar near the industrial area in Kadungalloor panchayat and Vyttila was 500 per 100 ml respectively against the prescribed limit of 50. The faecal coliform count was 280 per 100 ml in both the wells.

The maximum level of biochemical oxygen demand in the well located at Kalamassery near the NH 47 was 2.3 mg/litre against the prescribed limit of 2. Experts said that faulty septic systems and entry of surface water resulted in the contamination of the wells. Studies have found that leakage of leachate (black-coloured liquid) from the solid waste treatment plant at Brahmapuram had triggered the pollution of water bodies in Brahmapuram. The board has urged the residents to conduct regular tests of samples drawn from wells to ensure quality of the water used for various purposes. Proper maintenance of the septic system should also be carried out to check pollution.

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