Kochi: After a short gap, river Periyar turned black again near Pathalam regulator cum bridge on Saturday. Fish were also found dead.
"The river was found flowing in different colours from Saturday morning. Pungent odour was also emanating from the river. Fish started to die from the morning which indicates that presence of dissolved oxygen in the river has depleted. It is the discharge of effluents from industrial units which changed the colour of the polluted river," said Sakeer Hussain, activist of Periyar Malineek-arana Virudha Samithi.
Pollution Control Board officials visited the site and took samples. PCB environmental engineer P.B Sree Lakshmi told DC that the river turned black due to some anaerobic action due to depletion of dissolved oxygen level. "Though the river turned black no fish kill was reported. The discolouration and foul smell was due to stagnation of water. The water level receded drastically and the river is not flowing," she said.
The PCB official added that a report has been submitted to the district collector. "A request will be submitted to the collector urging him to instruct Irrigation department to open shutters of the Pathalam regulator cum bridge to reduce the pollution level and to ensure flow of river water," she added.
Discolouration of Periyar and fish kill has been a serious issue for last couple of years. Decrease in dissolved oxygen level has caused fish-kills more than 25 times in the past two years.