Fish found dead: Thane lake has zero oxygen to sustain aquatic life
On Thursday evening, thousands of dead fish were found floating in the Pandurang Bhoir lake
A day after thousands of dead fish were found floating in Pandurang Bhoir lake in Hari Om Nagar, samples collected from the lake revealed that dissolved oxygen level in the water is zero. This indicates a dead ecosystem.
Thane Municipal Corporation (TMC) officials said it was unnatural for such a large number of fish to be found in the lake and they will write to Kopri police to investigate illegal fish breeding in the lake.
On Thursday evening, thousands of dead fish were found floating in the lake adjacent to the dumping ground. The corporation removed the dead fish on Friday and initiated potassium permanganate treatment to clean the lake.
Manisha Pradhan, pollution control officer, TMC, said, “The water sampling report revealed that dissolved oxygen level in the lake is 0mg/litre, while the normal level for fish to survive should be 4mg/litre.”
The survey revealed that lake water is contaminated.
“Leaching (liquid that has dissolved or entrained environmentally harmful substances that may then enter the environment) from the adjacent dumping ground is the reason behind contamination,” she said.
Pradhan said there is also a cow shed near the lake.
“Water mixed with cow dung might be entering the lake, killing the eco-system. But despite its proximity to the dumping ground, not a single incident of fish dying was reported in the past three years. It is impossible for such large number of fish to die naturally. It looks like a case of illegal breeding. We’ll be writing to Kopri police to look into the matter,” she said.
She said that the corporation also needs to address seepage of leachate into the lake as the toxins will be harmful to the people who enter the lake for immersions during festivals.
“They can lead to skin irritation and other health problems,” she said.
Locals, however, alleged that the TMC never maintained the lake despite repeated reminders.
Bharat Chavan, local BJP corporator, who lives near the lake, said, “I had written to the corporation several times to maintain the lake. But the only time they act is during Ganeshotsav,” he said.
Admitting that the lake was not maintained, Pradhan said it would be monitored regularly after this incident.
“We are thinking of pumping out contaminated water before the monsoon so that fresh rainwater can revive the lake. Also, weekly sessions of potassium permanganate will help keep the water clean,” she said
