Heavy metal concentration in groundwater and soil samples from around NLC India Limited are within permissible limits, says the Tamil Nadu Pollution Control Board (TNPCB) in a report submitted at the National Green Tribunal (NGT).
In a suo motu case taken up by the southern bench of the NGT in August 2023 based on news reports about a report on pollution due to effluents from thermal plants in Neyveli, the TNPCB was directed to file a comparative test report.
As per the report titled ‘POWERing Pollution’, published by non-governmental organisations Poovulagin Nanbargal and Manthan Adhyayan Kendra in August 2023, high levels of mercury, selenium, and fluoride were found in drinking water from as many as 20 locations around NLC India Limited.
“Surface as well as groundwater sources at various places are affected by high levels of turbidity, hardness, total dissolved solids, total suspended solids, oil and grease and high Chemical Oxygen Demand. Equally worrying is the presence of elements like aluminium, boron, fluoride, iron, manganese, magnesium, mercury and selenium found in high concentrations,” the report stated.
The TNPCB, however, has said that groundwater samples reveal the presence of heavy metals within the permissible limit except in Vellankulam, where exceedance of aluminium to 0.139 mg/L as against 0.03mg/L was observed as prescribed by the Bureau of Indian Standards for drinking water.
“Soil samples collected by TNPCB committee for analysis reveals that there is no heavy metal contamination observed and the elements of zinc, cadmium, nickel, lead, arsenic, chromium, mercury and selenium are within the prescribed standard limit except the place of Vadakkuvellur, where some exceeded level was observed with respect to the zinc and nickel concentration. (zinc 492.7 mg/kg as against Canadian standard 250 mg/kg, nickel 99.62mg/kg as against Canadian standard 45 mg/kg),” it said.
