Significant contamination detected along Ashtamudi, Vembanad lakes

The Kerala State Pollution Control Board (PCB) has found significant contamination in a total of over 15 monitoring stations and drains along the Ashtamudi and Vembanad lakes.

he testing of water samples from these locations was carried out following an order issued by the Principal Bench of the National Green Tribunal to assess the extent of contamination in the two lakes identified as Ramsar sites of ecological importance.

A report submitted by the board before the tribunal dated January 20, 2026, said that significant contamination was found in a total of nine monitoring stations under the national and State water monitoring programmes in Kollam, Kottayam, Alappuzha and Ernakulam districts.

The sampling points that showed significant contamination in Kollam included Thoppilkadavu, KSRTC bus depot, Perumon, and Mundrothuruth. Four drains leading to the Ashtamudi lake also showed higher levels of contamination. It included Manichithodu, meeting point of Manichithodu and Ashtamudi lake, Kollam Thodu, and the meeting point of Kollam Thodu and Ashtamudi lake. In Kottayam, the affected locations included KV Canal, Anthakarathodu, and AC Canal.

Water samples taken from Kochi lake near Willingdon island and Kochi lake near the Cochin Port Authority showed significant sewage contamination. The canals that were found severely contaminated include Edappally, Mullasserry and Thevara-Perandoor canals. In Alappuzha, significant sewage contamination was detected at the monitoring stations in Chandiroor, Kakkathuruthu and Kayippuram, Muhamma.

The total coliform levels in the monitoring stations and drains ranged from 10,000 MPN (most probable number) per 100 ml to 780,000,000 MPN per 100 ml. The maximum permissible limit of total coliform in bathing water, as prescribed by the Central Pollution Control Board, is less than 2,500 MPN per 100 ml. The biological oxygen demand, a proxy for organic pollution, was above the ideal limit of 3 mg/l at some of the sampling points.