CHENNAI: What used to be a rare phenomenon, has become a regular feature on Chennai beaches. Heavy frothing was witnessed on Wednesday near Foreshore Estate coastline and experts attribute it to sudden influx of untreated sewage and chemical effluents from upstream into the sea through Adyar River.
A thick blanket of white foam is seen for about 2 km along Srinivasapuram and Pattinapakkam coasts. Heavy downpour in Adyar basin has increased the river flow. This, coupled with depression in Bay of Bengal and change in seasonal water current, has created a turbulence off-shore lead to frothing. Express had reported a similar incident in November last year.
Joe K Kizhakudan, a scientist with Central Marine Fisheries Research Institute, told Express, frothing happens due to the presence of non-biodegradable, detergent-like substances coming from municipal wastes and chemical effluents. “From October 27, the reversal of water current from south to north has started. Already, the sea condition is rough due to depression. Now, the stocked up sediment filled with high phosphate in Adyar estuary, will all gush into the sea due to heavy rains. All this makes a perfect recipe for frothing to occur.”
He said this may continue for a few more days till the Adyar river run-off reduces. This may even trigger bacterial bloom and surface bioluminescence organisms. To a query whether frothing is harmful for marine life, Joe said the coastal fishes will stay away but plankton and invertebrates like crabs in intertidal areas would suffer. “Frothing indicates very high alkaline water. All surface organisms will suffocate to death due to a respiratory problem, although it is only a short-time phenomenon. As more seawater exchange takes place, the dilution takes place,” he said. If the bar mouth is kept open continuously and there is constant flushing, this problem won’t arise, Joe said.
Pravakar Mishra of National Centre for Coastal Research, whose team monitored water quality of the coastline, also blamed the untreated sewage and effluents for the problem. “Our team will collect and analyse the water samples.”
When contacted, Tamil Nadu Pollution Control Board officials said they have collected the water samples and sent the same for chemical analysis. “This is clearly due of sudden flow of untreated sewage from Adyar estuary into the sea. There was foul smell.”