PCB study to find out reason behind fish kills in Periyar

Focus on Eloor-Edayar industrial stretch; project to start next summer

The Kerala State Pollution Control Board (KSPCB) has decided to carry out a comprehensive scientific study involving multiple agencies to ascertain the exact cause behind the frequent fish kills in the Periyar.

The study will start by the start of the next summer season. It will mainly focus on the Eloor-Edayar industrial stretch along the Periyar, which had witnessed several fish kills in the past.

“We plan to engage various other institutes and agencies to study the reasons behind the fish kills in the Periyar. The board will also collect its own data as part of the process,” said Ajit Haridas, Chairman of the Board.

Stating that it was not merely industrial discharge that was responsible for the fish kills, Dr. Haridas said that eutrophication (excessive richness of nutrients in a waterbody due to run-off from the land, which causes a dense growth of plant life) may have led to fish kills in the region. The waterbody then becomes excessively rich in nutrients leading to depletion of oxygen in the water, he said.

Dr. Haridas said that the flow of water along the Eloor-Edayar stretch was less in the summer months. “We feel that domestic discharge of effluents is creating this issue of nutrients in the waters,” he said.

The board chairman pointed out that pollutants generated on the stretch was accumulating in the area as the shutters of the regulator-cum-bridge at Pathalam remain closed during summer to check saline water intrusion from the sea. “It’s like a dam where pollutants accumulate leading to eutrophication,” he said.

Dr. Haridas said that the lack of sewage treatment plants in local bodies close to the Periyar remains a problem. These plants are required before discharging anything into the waterbody, he said. A study conducted by scientist Bijoy Nandan, professor at the Cochin University of Science and Technology (Cusat), had earlier recommended that the KSPCB and other governmental agencies take ‘immediate action’ to de-silt and de-sludge waste and other matter that had settled on the river bed, both upstream and downstream of the Pathalam regulator-cum-bridge.

Other recommendations included establishing a common industrial effluents treatment facility into which waste from houses, slaughterhouses and other small-scale industries can also be released and then treated water could be used for irrigation purposes.