Tests conducted by the Tamil Nadu Pollution Control Board indicate the presence of raw sewage in the water.

Delve Environment Wednesday, December 11, 2019 - 17:42

On November 29, the city of Chennai woke up to a frothing Marina shoreline, spewing foam onto the city's iconic beach. Communities near the beach initially ignored the steady foam and even let children play in it because it was a sight they witnessed every year.

But within the next three days it became apparent that this was no yearly phenomenon caused merely by the monsoon, as they believed. On December 2, the foam came up to their waistlines and almost entered their homes, alarming the residents in the area.

When TNM visited the spot and later engaged with environmentalists, it became clear that this was the result of a toxic cocktail of raw sewage mixed with sea water. It had been caused the city's unchecked dumping of domestic and industrial effluents in its water bodies.

Coastal Resource Centre's coordinator Sarvanan explained, "Two rivers in Chennai - Cooum and Adyar river - drain into the ocean here. When the river water mixes with the ocean water, if the river water is clean and there are no effluents, then you will not see much foam when the river water mixes with the sea water. However, both these rivers carry Chennai’s untreated sewage water. When this mixes with the rain water and joins the sea, the collision with the high density salt water in the ocean results in foaming. The ocean purifies itself by spitting out all toxins dumped into it, even if it is a plastic cover, it is eventually washed up on the shore. With the industrial and domestic effluents that mixed with the water, the ocean turns it into a foam on the seashore."

Fishermen near the beach told TNM that in the past, marine life has been affected by the foam, and that they fear repercussions this time around too.

Experts meanwhile say that to fix this problem there are four steps to be taken -  a multi-agency effort to plug untreated sewage that is entering Chennai’s rivers, ensuring that all neighbourhoods and settlements have access to the underground sewage connections, having storm water drains only carry storm water and not be allowed to be used as sewage outfalls. And finally, to ensure that all our sewage treatment plants have a capacity to handle more than optimum capacity.

Full Transcript

Instead of waves crashing into the sea, for 3 days the sea regurgitated foam onto the sands of Chennai’s famous Marina beach. November 29 until December 3,  a carped of froth lined the shore of the beach.

For at least a kilometre from the Broken Bridge to the lighthouse, this  foam has been washing up on the shores of Pattinambakkam beach for the last three days. When it first began on Friday, the residents (fisherfolk) on the beach were not alarmed as the foam as a yearly phenomenon. However, on Monday morning, the foam washed up right up to their houses and came up to their waists. This is when they realised that this was not just a yearly phenomenon, and that they had cause to worry.

Thirty six year old Muthumani from Pattinambakkam in Chennai woke up on December 2 morning to discover that the foam had almost entered her residence.

“Usually the foam comes and goes and the children play. Today the foam had increased exceptionally and we got scared. Everyone kept saying that there was going to be another Tsunami. I couldn’t sleep a wink all night. When I woke up this morning, there was foam like a wall in front of my house. It came up to my waist. When I saw the foam, I got scared and woke my family up. I told them that the foam might enter our houses. Everyone came and saw. The government only had to do something about it,” Muthumani tells TNM.

With several children including hers playing in the foam for several hours, Muthumani fears there could be health repercussions.

“We don’t know if this will create any diseases for our kids,” she says.

Sources in the Tamil Nadu Pollution Control Board (TNPCB) attribute the foam to farm fertilisers and pesticides that are being washed into the sea with rain water.

But when TNM accessed a November 29 report of tests done from Pattinambakkam and the Adyar river, there was no data on heavy metals found - a crucial test when looking for remnants of these chemicals.

What the tests did prove however were excess levels of Phosphate and Ammonia in the water.

While Phosphate indicate the presence of detergent, Ammonia hints at the presence of raw sewage. Environmentalists say that it is this toxic cocktail created by the release of sewage into sea water that is causing the foam. While the dumping of sewage happens all through the year, when monsoons arrive the problem is aggravated.

During the monsoon, inflows into Chennai’s sewage treatment plant increase, reducing its efficiency. And this results in more untreated sewage entering the city’s water bodies.

According to Saravanan, a coordinator at Coastal Resource Centre, “Two rivers in Chennai - Cooum and Adyar river - drain into the ocean here. When the river water mixes with the ocean water, if the river water is clean and there are no effluents, then you will not see much foam when the river water mixes with the sea water. However, both these rivers carry Chennai’s untreated sewage water. When this mixes with the rain water and joins the sea, the collision with the high density salt water in the ocean results in foaming. The ocean purifies itself by spitting out all toxins dumped into it, even if it is a plastic cover, it is eventually washed up on the shore. With the industrial and domestic effluents that mixed with the water, the ocean turns it into a foam on the seashore.”

Several fishermen in the area have not gone out to sea due to the rains for a week…And with foam spewing out onto the beach, fishermen say it has not only damaged their nets but they worry over its effect on marine life.

“We haven't gone to the sea for two weeks since the rain began. And now because of the foam which is coming we have stayed away. This is because of sewage water coming from the Kotturpuram area. In the past, fish have died in that area because of this,” says Surendran, a fisherman at Pattinambakkam.

Saravanan says that sewage draining into the water does affect marine life. “ The industrial effluents, heavy metals, plastics and other waste flowing into the ocean kills the oxygen levels in the water. Moreover, these toxins also settle on the ocean bed, affecting the tiny marine life there. The plastic being washed into the ocean is consumed by the big fish, which also die as a consequence. So the foam as such is not dangerous. The real killers are what causes the foam.”

Experts say that the froth is merely a symptom of the larger problem which needs to be addressed...how the city manages its sewage. To begin with, a multi-agency effort would be required to plug untreated sewage that is entering Chennai’s rivers.

“Second thing is to ensure that all neighbourhoods and settlements have access to the underground sewage connections. Third thing is to ensure that all storm water drains only carry storm water and is not used as sewage outfalls because in most neighbourhoods the storm water drains are not connected to any sewage treatment plants (STPs) but have direct outfalls. And the most important thing would be to ensure that all our sewage treatment plants have a capacity to handle more than optimum capacity. So if we are expecting about 300 MLD then to ensure that the STP can handle more than that when it is monsoon and there is excess run off,” Pooja Kumar, researcher, Coastal Resource Centre tells TNM

Only a concerted effort by the government and its agencies will prevent Chennai’s Marina beach from turning into a carpet of foam every year.