Residents in Eloor municipality and Kadungalloor panchayat living close to the Periyar are an anxious lot once again with the colour of the river changing to a thick black, and later white on Saturday morning and fishes appearing to be affected by the depletion of dissolved oxygen and coming up to the surface in distress.
A large number of kites and other birds of prey were seen hovering over the area near the Pathalam regulator-cum-bridge from about 9.30 a.m. as fishes were floating almost lifeless on the surface. However, Adam Kutty, an environmental activist living in Eloor, said there was no noticeable kill though fishes were seriously affected by the changes in the river.
Mahesh Kumar, another resident of Eloor, said that people noticed the colour change in the late morning hours and the local office of the Kerala State Pollution Control Board (PCB) was informed. An official said that samples had been collected for testing and that a report would be submitted to the District Collector on Saturday.
The PCB official said that sewage water and solid waste discharge from neighbouring municipalities and other local bodies is still continuing and the change in colour and depletion of dissolved oxygen were common occurrences. However, residents in the area and environmental workers have blamed the industrial units along the Periyar for the pollution.
A statement issued by the PCB said it was continuously monitoring the industries on the river banks and that action would be taken against erring units.
The statement said that a green coloured layer was found at the downstream of the river on Friday. The green colour indicates the growth of algae. Algae use up oxygen in water and it results in the depletion of oxygen during night hours. On Saturday morning, the river was found to be black in colour and oxygen level appeared to be very low.
Fishes were seen coming to the surface due to oxygen depletion. Oxygen level is minimum during early morning and gradually increases during during day time. At present, the quantity of water in the river is very low. The dissolved oxygen level in the morning was reported as one mg/lit which is less than required for aquatic life. The obstruction of river flow and low level of water are major factors that cause depletion of oxygen.
