Dhaka Water Supply and Sewerage Authority (Wasa) has destroyed fishes in four polluted lagoons in the city over a week but another 12 water bodies are yet to be attended to.
The situation poses a potential threat to public health as illegal fishing in the lagoons lead to these harmful fishes ending up in the kitchen markets of the city.
"We have already sent a proposal to the Wasa head office for permission to take up the 12 other lagoons," Wasa Executive Engineer Kamrul Hossain Bhuiyan said.
Wasa destroyed the fishes in two lagoons using poison in two separate drives on August 30 and September 6 at a cost of Tk 60,000 per lagoon.
Though Wasa banned both fishing and fish cultivation in these city lagoons almost 10 years ago, certain illegal activities remain. The lagoons contain human waste and industrial wastes and fishes cultivated in these water bodies have high levels of metal in their system, a Wasa official said.
These include heavy metals like chromium, cadmium, arsenic, lead, nickel and mercury, experts say, which can be very harmful for the human body if these fishes are consumed.