Oil contamination, oxygen depletion behind mass fish deaths in Gorakhpur pond

Gorakhpur, Nov 6 (PTI) The mass fish deaths in Surajkund pond here last month were caused by oil contamination and severe oxygen depletion in the water after festivals, an analysis has revealed.

According to a water sample analysis conducted by Narayan Laboratory and Consultancy in the Gorakhpur Industrial Development Authority (GIDA) area, the pond water showed abnormally high levels of oil and organic pollution in the days following Diwali and Chhath.

The tests were ordered by Anita Agarwal, patron of the Heritage Foundation, after residents reported the sudden death of fish in the pond.

Lab engineer Saurabh Dubey, who collected samples on October 31, said the water had a pH level of 7.61 and a dissolved oxygen concentration of 5.6 mg per litre, which is within the acceptable range, suggesting partial recovery.

However, the biochemical oxygen demand (BOD) was recorded at 4.5 mg per litre, and the chemical oxygen demand (COD) at 120 mg per litre, indicating high organic and chemical pollution.

Oil and grease levels were found to be nearly four times the permissible limit.

Experts said during the festivals, oil, ghee, flowers, and other offerings were released into the pond that formed a thin layer on the surface that blocked the transfer of oxygen.

"Small fish would have suffocated first, while larger ones likely died later after consuming contaminated water or prey," said Sahil Mahfuz of Deen Dayal Upadhyay University's Industrial Microbiology department, who examined the findings along with Dubey.

The experts described the episode as a case of "oxygen shock and oil poisoning", noting that dissolved oxygen levels might have dipped below 2 surface on October 29, before the rain and inflow of fresh water improved the conditions slightly.

Following the report, the Heritage Foundation urged local authorities to enforce ecological safeguards and restrict the dumping of ritual offerings and waste into public water bodies. PTI COR KIS ARB VN VN