4 October, 2021. Chennai — Even as environmental sampling data from Pambar Shola and River clearly indicate mercury exceeding levels of concern in soil, sediment and moss, Unilever’s consultant NEERI has downplayed the dangers by comparing the data with incorrect standards to conclude that the Unilever site is not a threat to the Pambar Shola ecosystem. In NGT’s suo motu case, a joint committee of CPCB and TNPCB too have submitted an uncritical report concurring with NEERI’s conclusions without taking any samples of their own from Pambar watershed.
Sediment samples taken from Pambar Stream returned with values as high as 0.251, 0.256 and 0.412 mg/kg. The Canadian Interim Sediment Quality Guideline (ISQG) for mercury is 0.17 mg/kg. Adverse effects will occur at levels above this threshold. According to the same guideline, the incidence of adverse biological effects is as high as 34% when mercury sediment levels are between 0.17 mg/kg and 0.486 mg/kg. NEERI’s findings are between 1.5 and 2.4 times higher than safe levels. Instead of comparing the sediment results with the ISQG, NEERI has compared it with the “Probable Effects Level” (PEL) of 0.486 mg/kg, which represents a level above which adverse effects are even higher. The presence of such high levels of mercury in sediment 20 years after the factory has closed is a clear indicator that the factory site is continuously leaking mercury into the Pambar watershed – a fact that NEERI and Unilever have consistently suppressed.
A soil sample taken from within the Kodaikanal Wildlife Sanctuary returned with 4.7 mg/kg of mercury. That is 470 times higher than background levels (< 0.01 mg/kg) in the same data set from other parts of the sanctuary. Mercury should be below detectable levels inside the sanctuary. A sample of moss taken from near a stream entering the sanctuary from the factory site had 6.36 mg/kg of mercury. That is 795 times higher than background levels (<0.008 mg/kg) in NEERI’s data set from other parts of the sanctuary. Moss accumulates nutrients from the surrounding air. The high level of mercury suggests that the stream bed may be an active source of mercury vapour.
NEERI’s misleading conclusion and TNPCB, CPCB’s uncritical approval exposes the lack of integrity in scientific and regulatory bodies. The Tamil Nadu Forest Department, whose responsibility it is to protect the sanctuary, must not be lulled into complacency. Far from signalling that there is no risk, NEERI’s study results are a wake-up call for action to protect the sanctuary.
In January 2020, Unilever felled 440 trees bypassing the appropriate authorities. Tree felling within the then 10 km Ecosensitive Zone of wildlife sanctuaries requires permission from the Principal Chief Conservator of Forests. Unilever did not even approach the PCCF. TNPCB has failed to assess the impact of clearfelling on rainwater and mercury runoff from the site to the sanctuary.
This is not the first time that NEERI has misinterpreted data in favour of Unilever. In 2007, it successfully argued for downgrading cleanup standards from 10 mg/kg to 25 mg/kg stating that tighter standards would mean higher expense for clean-up. In 2015, NEERI found sediment mercury levels as high as 0.507 mg/kg in Pambar Shola – well in excess of the 0.486 mg/kg PEL that it has used as a standard in the 2021 report. However, NEERI did not use this value. Instead, it explained away the findings as insignificant by comparing it against a contested soil standard of 20 mg/kg. Mercury in freshwater sediments pose a far higher risk than in soil. “Comparing sediment mercury levels inside a wildlife sanctuary with soil clean-up targets for future residential or industrial use is worse than comparing apples and oranges,” said Nityanand Jayaraman of Chennai Solidarity Group.
For more information, contact: Nityanand Jayaraman: 9444082401. Chennai Solidarity Group
NEERI report: https://kodaimercury.org/ecological-risk-assessment-neeri-2021-as-per-ngt-order/
Canadian Council of Ministers of Environment sediment standards available on request.