Thick layer of froth blankets 1.5km of Chennais southern coast

CHENNAI: A thick layer of white froth covered nearly 1.5km of the citys coastline between Pattinapakkam and Srinivasapuram on Wednesday. Officials said the frothing followed intense rainfall over the Adyar basin, which increased river discharge into the sea. The flow, mixed with untreated sewage rich in phosphates, created a churning effect at the Adyar estuary that resulted in the formation of froth. Despite the government spending hundreds of crores on restoring Chennais waterways, Adyar, Cooum and Buckingham Canal continue to carry untreated sewage, with illegal outfalls still unchecked. Experts warn that the foam poses public health risks, particularly along crowded beaches like Marina, Thiruvanmiyur, and Besant Nagar, where contact with the froth could cause skin irritation, especially in children. Tests conducted by the Tamil Nadu Pollution Control Board (TNPCB) during earlier instances found that while pH and dissolved oxygen levels were within limits, phosphate concentrations were high, possibly triggering frothing. Data from the National Centre for Coastal Research (NCCR) buoy on the Chennai coast also indicated pH and oxygen levels were within normal range. NCCR scientist Pravakar Mishra confirmed phosphates as the cause. There is no real-time sensor to measure phosphate content, but our studies show its the main factor behind frothing. It is toxic and can cause skin problems if exposed for an extended period, for instance, among fishermen, he said.