Fly ash devastates fish wealth, public health in Ennore

CHENNAI: There was time when fisherman Marimuthu used to net scores of kilos of in-demand fish varieties teeming in the Kosasthalaiayar river. But then the environment impact of the North Chennai thermal power plant began to show.


Now aged 60 years, Marimuthu could catch just a few kilos of fish and prawns now, after spending over four hours in the waters. The quality of catch has shrunk, too. Fish and prawns are dark as their internal organs are lined with fly ash. His children have moved to gardening and other daily wage jobs, he said.

Though supposed to be used up 100%, presence of heavy fly ash deposits has been documented in a study of the Ennore wetlands and the surrounding areas. About 65 lakh tonnes of fly ash is estimated to be in rivers, backwaters and surrounding areas. Fly ash deposits were found in about 1-8feet. Due to this, heavy sediments of Cadmium, zinc, nickel, sulphur, copper and lead was found in the Buckhingam canal, Ennore Creek, groundwater and river sediment. This has led to the water bodies shrinking from 855 hectares in 1996 to 277 hectares in 2022. Natural drainage patterns have also been altered due to the fly ash pond construction. The adverse impact on aquatic life is the worst -- more than a dozen fish species, including white prawn, black prawn, tiger prawn, green crab, silver biddy, have all vanished.

A National Green Tribunal-appointed expert committee chaired by retired IAS officer Shantha Sheela Nair, reported that out of 3.51sqkm of fly ash prevalent across the Ennore area, about 1.51sqkm was within the waterbodies. “The actual extent could be much larger as the study was not carried out in areas west of the ash pond. In addition to fugitive emissions directly from fly ash pipelines, the natural macro drain for storm water run-off connected to the fly ash pond area also seemed to be a major carrier of fly ash into the Ennore backwaters,” it said.

Shantha Sheela Nair said the Ennore Creek alone, despite this degradation, still provided ecological services worth Rs 12.36 crore a year. This was also substantiated by a recent study by the Madras Institute of Development Studies (MIDS). “If notified and restored, the waterbody can be put to wise use. This is possible only if Tangedco functions with valid licenses, including consent to operate and hazardous waste authorization. And the state government ensures experts are involved to remove all deposits of fly ash from the Kosasthalaiayar river bed and shore, Buckhingam canal shore and bed, and from the estuary,” Nair said.

Jayshree Vencatesan, Balaji Narasimhan and D Balaji, all biodiversity experts who were part of the committee, said each hectare of mangrove produced 1.86 tonnes of yearly marine fish capture in India, which accounts for around 23% of the country's total catch.

“Despite the heavy contamination of water in Ennore estuary, the window pane oyster species, along with other edible oyster species, have shown resilience to the harsh polluted environment. Similarly, several flora and fauna have emerged resilient to the contamination. About 482 species of flora and fauna have been found. Also, the mangrove cover has gone up in the past decade due to plantation activities,” stated Balaji Narasimhan’s report.

Parthasarathy, a local fisherman, says: “If action is not taken to desilt these water bodies and protect them, soon, we fishermen along with these extinct species, would become a museum specimen.”


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