The alarming number of times that Kerala’s Periyar River has changed colour has caught the attention of a panel set up by the National Green Tribunal (NGT) in the state. Retired Justice AV Ramakrishna Pillai, the chairman of State Level Monitoring Committee formed by NGT visited the river on Sunday to investigate the causes. The stretch of the Periyar River near Eloor industrial belt in Ernakulam district had recently changed colour from green to black.
After conducting an inspection in the area, Justice Ramakrishna Pillai told TNM about his observations over the issue. “The main reason which contributes to the present issues of the river is stagnation of water. The green colouration of the river was due to the algal bloom which probably would be because of increase in nutrient levels of the river due to stagnation,” said the retired judge.
“The algal bloom also indicates that there is an inflow of organic materials, probably sewage into the river. Increasing algal population contributes to oxygen depletion in the river that can also lead to fish death,” he said.
On Friday, a green layer was found downstream of the Periyar river which turned black in colour on Saturday morning. Kerala State Pollution Control Board’s (KSPCB) Chief Environmental Engineer at the surveillance centre PB Sreelakshmi attributed the river turning black to the waterbody’s anaerobic condition (without oxygen). The dissolved oxygen level on Sunday was reported to be 1 mg/litre which is very much less than what is required for aquatic life.
This had created panic among environmentalists as fishes were also seen coming to the surface of water for oxygen.
Fishes seen surfacing on the river on Sunday because of low oxygen level
However, Justice Ramakrishna Pillai also pinned the blame on industries that were dumping effluents into the river and on the KSPCB which was lax in monitoring the area. Pulling up KSPCB, Justice Ramakrishna Pillai said, “Though the Kerala State Pollution Control Board has a surveillance centre in Eloor which monitors the industrial discharge into the river, they have to function more effectively.”
According to him, though KSPCB has installed surveillance cameras in the area to check industrial effluents, this was not being done effectively. “There are thick outgrowths of grass in some areas. This will give a chance for the factories to release effluents through storm water outlets without the knowledge of KSPCB. When something like this happen, the result will be only visible when either the colour of the river changes or when fish death occurs,” he said.
However, KSPCB attributed the change in the colour of the river to the fact that the Irrigation Department has closed all the shutters of Pathalam regulator-cum-bridge which regulates the flow of river. The decrease in water lever in the river has been cited as the reason for closing down the shutters.
KSPCB’s Chief Environmental Engineer at the surveillance centre PB Sreelakshmi told TNM that Irrigation Department should operate the Pathalam regulator regularly according to daily tidal effect. “Irrigation Department only operate the shutters of the regulator cum bridge just one or two times in a week. This has an important role in lowering oxygen levels in the river,” said Sreelakshmi. KSPCB will also give a written request to Irrigation Department on Monday to take into consideration these matters.