Postmortem of fishes confirms Ambazari lake highly polluted

Nagpur: The post mortem examination of dead fishes and water tests have confirmed Ambazari lake water is highly polluted due to flow of untreated industrial waste and sewage water. However, Nagpur Municipal Corporation (NMC) is yet to initiate any steps to stop the pollution.
TOI had reported on April 13 that fishes were dying in Ambazari lake in large numbers. Nagpur bench of Bombay high court had treated TOI’s report as suo motu public interest litigation (PIL) and issued notices to the respondents, including NMC.
NMC asked Nagpur Veterinary College to conduct post mortem of fishes, and directed state government’s Regional Public Health Laboratory (RPHL) to test the water.
The post mortem report from Nagpur Veterinary College says the fishes died due to septicaemia or toxicity. “Haemorrhagic spots observed on ventral part as well as fins of fishes. Necrotic foci observed on liver and distended bladders,” the report said.
Expert Kaustav Chatterjee said the report means fishes died due to blood poisoning. “It is basically caused due to flow of untreated industrial and sewage waste. It means water contains toxins,” he said.
NMC officials said Neeri has been asked to give a detailed analysis of the cause of fish deaths. “Water samples from various points of the lake have been collected and submitted to Neeri. Also, Neeri will suggest measures to be taken at the water body. Then, we will decide the works to be undertaken at the lake,” they said.
The water test report of RPHL revealed heavy metals, like iron and magnesium, in the water, though within permissible limits. Chatterjee said this indicates flow of industrial waste into the water body.
Also, level of dissolved oxygen (DO) was found to be lower than permissible limit. It also mean high level of pollution. DO was 2.2 mg/l in one spot, 3.6 mg/l at two spots, 4.1 and 4.2 mg/l at two spots. DO should ideally be above 5-6 mg/l.
Chatterjee said DO reduces to a great extent due to flow of untreated industrial waste and sewage. “Value of DO at 2.2 mg/l is alarming. Industrial waste contains elements that cause this condition in water. Sewage contains nitrogen and phosphorous. These two also reduce DO level. Such values of DO level are harmful for fishes, cattle etc,” he said.
Value of turbidity is also very high as compared to permissible limits. Physical appearance of the water was found to be blackish, brownish, yellowish and hazy at different locations.
NMC officials said even oily substance was seen on water’s surface.
TOI has been reporting on death of fishes at Ambazari since 2014, but NMC has taken no steps for last many decades to stop flow of untreated sewage and industrial waste into the lake. Nagpur Improvement Trust (NIT) has started constructing a 5 million litres per day (MLD) sewage treatment plant on Nag river just ahead of Ambazari lake.