Many of the lakes in Hà Nội have been cleaned up, but the water is still contaminated with organic pollutants, the municipal Department of Construction has said. Ba Mau Lake, Đống Đa District, Hà Nội. — Photo infonet.vn

HÀ NỘI — Many of the lakes in Hà Nội have been cleaned up, but the water is still contaminated with organic pollutants, the municipal Department of Construction has said.

Director of the department, Lê Văn Dục said that among 120 lakes in the city, 84 had been completedly cleaned up and 10 others were being cleaned.

Despite being cleaned, a large amount of rain and waste water from residential areas had been flowing into them. Some lakes were equipped with built waste blocking systems and the water quality improved, but they were contaminated with organic waste. Among them are West Lake, Trúc Bạch, Thanh Nhàn, Linh Đàm, Nghĩa Tân and Kim Liên lakes.

Speaking at a conference on Tuesday, Dục said another 26 lakes which were seriously downgraded had not been cleaned up. Linh Quang, Tứ Liên, Đại Kim, Tân Thụy and Phùng Khoang were among the most polluted lakes, with construction waste and garbage around the embarkments.

To improve the ecological system of the lakes, the city People’s Committee had established a steering committee for environmental pollution of lakes, led by the committee’s chairman Nguyễn Đức Chung.

Initially, the Hà Nội Water Drainage Company, in collaboration with institutes, applied new technology – Redoxy 3C from Germany – to clean the lakes of Hố Mẻ, Giáp Bát and Ba Mẫu in a September pilot project.

The company would submit a plan to clean other lakes next year if the trial shows positive results, it said.

In reply to massive fish deaths in the city’s lakes, Dục said that a shift in the weather, leading to the sudden decrease of oxygen, was likely to be the cause of the fish deaths in Linh Đàm Lake in Hà Nội’s Hoàng Mai District.

He said the final conclusion would be announced by the Department of Natural Resources and Environment, but affirmed that the lake was among the less polluted in Hà Nội.

On October 26, a large number of fish were found dead in Linh Đàm Lake, with residents claiming polluted water was the main reason.

Thousands of fish, including tench, carp and plaice, weighing 5-6 kilogrammes each, were found dead along a one-km-long lake dyke area. Many of the fish were badly decomposed, exuding a bad odour. — VNS