The fish died due to the low concentration of dissolved oxygen in the water of West Lake, at 1.5 mg/l, while fish need higher concentration of oxygen dissolved in water, minimum 6mg/l.
Weather fluctuations in recent days was also identified as one of the causes of mass fish dead in West Lake.
Mr. Mai Trong Thai, Deputy Manager of the Environmental Protection Branch (Hanoi’s Department of Natural Resources and Environment) has made this preliminary statement on October 2 after his unit has conducted water samplings of West Lake for analysis to find the cause of the incident.
|Dead fishes in West Lake in Hanoi (Photo: VNA)
The water samples will be analyzed carefully and the official result will be released in few days, he added.
According to Mr. Mai Trong Thai, the Hanoi’s Environmental Protection Branch has checked the discharge gates surrounding the West Lake, none of unauthorized has been found.
Earlier, a large number of dead fish were discovered in West Lake. Fish spread all over the lake, focused in downwind areas along Nguyen Dinh Thi and Van Cao streets.
|Workers collect dead fishes floating in the polluted West Lake. (Photo:Reuters)
Many of them have big weight, tench and tilapia of around four kilos each.
The fish had bellied up along the shore of the largest lake in Hanoi, making smelly spots.
Despite the heavy stink, some people are using baskets to collect the rotting fish. They said they are going to use them as fertilizer.
The Tay Ho District People’s Committee has directed local authorities to control all discharge system of restaurants, business locations around West Lake.
Environment workers of the West Lake Environment Company were also asked to clean up the lake. PSN