TNPCB report shows high level of mercury contamination in water sources near NLCIL

TNPCB study shows high mercury levels in water near NLCIL, prompting NGT intervention and calls for immediate action.

A study conducted by the Tamil Nadu Pollution Control Board (TNPCB) on the directions of the National Green Tribunal (NGT), Southern Zone, has shown elevated levels of mercury in waterbodies located near Mines I, 1 A and II and Thermal Power Station II of NLC India Limited (NLCIL).

The TNPCB study, with water samples collected on December 17, 2024, was undertaken following the intervention of the NGT. The report was submitted before the tribunal on Wednesday.

The NGT had suo motu taken up the case following the publication of the report ‘Powering Pollution’ by NGO Poovulagin Nanbargal in association with Mandan Athayayan Kendra, on the environmental and health degradation caused in areas adjacent to thermal power plants in Neyveli and the location of mining operation in Parangipettai of Cuddalore district. 

The NGT had directed the TNPCB on August 10, 2023 to inspect the area, collect water and soil samples and ascertain the quality of the waterbodies near NLCIL.

According to the 14-page report, 32 samples of surface water, groundwater and soil had been collected from a wide area, including the Paravanar river, Walajah lake, Iyyan lake, Buckingham canal near the Thermal Power Plant, Mine I outlet at Veenageni, Vadakkuvellur pond near Sivankovil, Muappaneri village, NLCIL supplied water at U. Mangalam tank, Block-22 powerhouse (Jawahar college), Pudhukuppam and Karikuppam village.

Of these, the concentration of total mercury was found to be above the permissible limits of drinking water standards in the range of 0.0012 mg/l to 0.115 mg/l in 15 out of 17 surface water samples. In Buckingham canal, one of the sites where water samples were collected, the concentration of mercury was found to be 115 times more than the permissible limit.

The water samples taken from the canal showed total concentration of mercury of 0.115 mg/l as against the permissible limits. Though the results show high levels of mercury, the TNPCB in its report said that as per Surface Water Standard IS 2296 Class E (not fit for drinking), there is no limit for mercury.