The gas well blowout in Assam’s Tinsukia district has polluted the Lohit river and adjoining eco-sensitive Maguri-Motapung wetland and toxic pollutants may have killed fish, insects as well as pose risk to endangered Gangetic dolphins in the region, a preliminary Wildlife Institute of India (WII) survey report has said. It has cited interviews with locals and said the Oil India Limited (OIL) did not have a mitigation plan for such accidents. WII has hence suggested a comprehensive impact assessment of entire OIL field operations in the biodiversity-rich area. The well caught fire on Tuesday days after the blowout, or leakage of gas and condensate, began on May 27. Dibru-Saikhowa Biosphere Reserve (DSBR) located nearby is home to endangered hoolock gibbons.

The Union environment ministry gave the environmental clearance to OIL on May 11 for extension drilling and testing of hydrocarbons at seven locations under Dibru Saikhowa National Park. The report said the fumes and oil coating has affected flora and fauna.

“The contaminants and oil are continuing to be released in surrounding areas and immediate steps are needed to contain this spillover. The toxins released are known to have long-term persistence in soils and sediments, which will not only affect current life conditions but due to sustained release over a long period, pose a serious health risk for a longer-term,” said the report, a copy of which HT has seen, submitted to the ministry.

WII scientist Qamar Qureshi said the region’s lowland forests are unique and they have found other wells are also leaking which can have long term impacts. “We have recommended a thorough assessment of disaster mitigation possibilities before implementing any more exploration projects,” he said.

Soumitra Dasgupta, additional director-general (wildlife), environment ministry, said the wetland is affected and so are the aquatic species.

“The national park is slightly away from the accident site. We will wait for the detailed WII study and response from the Assam forest department. We have written to them.”

An OIL spokesperson did not comment on the report saying they are unaware of it. “Whatever condensed oil had been released earlier has been burnt off. There is no contamination from it anymore. We are trying to contain the gas which is releasing within four weeks.”

WII, which carried the survey from May 29 to June 4, has recommended that the approved new wells and further exploration in the area be put on hold until OIL has disaster handling capabilities. It found the presence of at least five Gangetic dolphins in the 20 km stretch of the Lohit river it surveyed and indicated that they will be at grave risk from the ongoing spill.

The team has collected samples of tissue and blubber from a dolphin carcass, which is being analysed for the presence of various contaminants. WII said new wells and explorations in this area should be initiated only after a thorough evaluation.

It will come out with a detailed report on the impact on the region’s biodiversity by the month-end. WII has also flagged the long term environmental impacts of the spill as a blowout spews hundreds of chemicals in the air, water, and soil.

Residents of the area reported severe breathing difficulty, headaches, and nausea to WII. Even the WII survey team experienced similar symptoms due to the heavy presence of oil. The entire landscape, including the wetland, is coated in layers of oil, WII said.

The biodiversity-rich area is one of the important remaining habitats of several endangered and range-restricted species, according to WII. DSBR is also home to tigers, elephants, wild buffalos, leopards, capped langurs, slow loris, as well as critically endangered bird species such as the Bengal florican, white-winged wood duck, greater adjutant stork, white-rumped vulture, slender-billed vulture. The rare and endemic black-breasted parrotbill is found there.