CHENNAI: Following the heavy downpour, the waves on the Marina and Pattinapakkam beaches turned black. On Friday, a number of visitors to the beaches were taken aback by the sudden change of colour. The stench emanating from the seawater at the Marina was also unbearable.
“After rains, the colour has changed. It is black and the stench is also strong. This could be due to a lot of sewage mixing with rainwater. This happens after rains. The waves on the Pattinapakkam beach also turned black,” said S Dhanapal, a fisherman in Nochikuppam.
“During rainy days, usually near the shore, water gets polluted and turns black. This is due to a lot of land waste going into the sea. It is also due to turbidity. A few days after the rains stop, the colour will turn back to blue,” said S Felix, vice-chancellor, Tamil Nadu Fisheries University.
“This could be a local phenomenon because of rains. We can’t say it is due to oceanic changes. This local change would become normal after the rains stop. However, we need to test samples before coming to a conclusion,” said a scientist from the Central Marine Fisheries Research Institute.
A senior Metrowater official said that only effluents are let into the sea and there is no chance of sewage getting directly into the sea. “It is true that the volume of sewage at the treatment plant has increased due to the rains as compared to normal days. But we let only effluents into the sea after treatment.
If there is any chance of sewage mixing into the sea via the Buckingham canal or the Adyar river, it should be from the houses constructed on the Cooum beds. That should be only five per cent,” the official added.