Soil sampling done by NEERI from the Pambar stream showed mercury levels between 1.5 to 2.4 times higher than what is considered ‘safe’.

Unilever NEERI downplaying high mercury level risks at Kodaikanal site Activists
news Environment Tuesday, October 05, 2021 - 18:36

The Hindustan Unilever and its environment consultant NEERI (National Environmental Engineering Research Institute) have downplayed the exceeding level of mercury found in Pambar stream and the Kodaikanal Wildlife Sanctuary area from an environment sampling test done recently, say activists. Environmental activists from Chennai Solidarity Group, which has been shedding light on HUL issue, now says that data from the environment sampling study done by NEERI showed that mercury levels were exceedingly high in the soil, moss, and sediment samples taken from the Pambar stream. However, the group states that both HUL and NEERI have compared this data to “incorrect standards” to make it seem like the HUL site in Kodaikanal is not a threat to the Pambar Shola ecosystem, a press release by the Chennai Solidarity Group states. 

Explaining the study, activists say that sediment samples taken from the Pambar stream returned with values as high as 0.251, 0.256 and 0.412 mg/kg. According to the Canadian Interim Sediment Quality Guidelines (ISQG), anything above 0.17 mg/kg is considered not safe. ISQG says that 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. 

According to NEERI’s findings, the mercury level in the Pambar sediment is 1.5 to 2.4 times higher than what is considered a ‘safe level’. However, instead of comparing the results with the ISQG, NEERI has compared it with the Probable Effects Level (PEL), which says that of anything that has mercury levels above 0.486 mg/kg the “adverse effects are even higher”. By PEL’s scale for comparison, the findings of mercury levels of 0.251, 0.256 and 0.412 mg/kg would below range, while they are still extremely harmful, activists say.

“The presence of such high levels of mercury in the 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,” the press release added.

Additionally, during the hearing of a suo motu case by the NGT, a joint committee of the Central Pollution Control Board and the Tamil Nadu Pollution Control Board submitted an uncritical report concurring with NEERI’s conclusions without taking any samples of their own from Pambar watershed, the group adds.

Mercury levels in Kodaikanal Wildlife Sanctuary alarming

The press release also highlights that a soil sample taken from within Kodaikanal Wildlife Sanctuary returned with 4.7 mg/kg of mercury. This is 470 times higher than that of samples taken from other parts of the sanctuary, further away from the factory, which were found to have mercury levels of 0.01 mg/kg.

Though 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 was found to have 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.  

The group also adds that the high level of mercury indicates that the stream bed may be an active source of mercury vapour.

In January 2020, Unilever cleared all vegetation including 425 trees from its property in Kodaikanal which had high soil mercury concentration, which has now exposed the toxic soil inside the Unilever premises and potentially allowing it to wash into the Kodaikanal Wildlife Sanctuary and the Pambar-Shola. Following this, 65 artists, educators, ecologists, and environmentalists wrote to Tamil Nadu Chief Minister Stalin urging the state to take action against HUL for cutting down hundreds of trees in Kodaikanal.

“Trees or vegetation provide protection on three levels - the canopy, the undergrowth and the leaf litter. In an area like Kodaikanal, which sees heavy rainfall, these three layers can offer protection from soil erosion. The clearing of over 400 trees from the Kodaikanal site and removal of vegetation has exposed the soil (which is rife with mercury). With rains, more soil is likely to erode, which leads to more mercury eroding into the Pambar stream and the sanctuary,” explains Nityanand Jayaraman, a Chennai based environmentalist who is member of the Chennai Solidarity Group.

Explaining why increase in mercury in soil sediment can be harmful, he adds “Mercury becomes even more lethal underwater as it turns into a chemical called Methylmercury. This enters the aquatic food chain and can spread right up to the big predators in the river and the sanctuary. Therefore, it’s very important to keep mercury levels leaking into the river in check,” he adds

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