The water from Nhuệ River passing through Hà Nội's Đông Anh District has been recorded severe polluted. — VNA/VNS Photo Phương Anh

HÀ NỘI — The quality of surface water in many lakes and rivers in the north has improved, but 15 monitoring areas of 185 that have been monitored remain heavily polluted, mainly on the Cầu and Nhuệ-Đáy rivers.

River water in the capital Hà Nội was also seriously polluted.

The water quality monitoring assessment was carried out in May at 185 monitoring points in five river basins by the Centre for Environmental Monitoring in the North.

According to the report, the water quality in the Cầu River has improved compared to the same period of last year.

At the monitoring points in the upstream area in northern Bắc Kạn Province, river water was deemed clean enough for daily use with the water quality index (WQI) in a good range between 89-92.

On the Cầu River running through Bắc Giang and Bắc Ninh provinces, most of the WQI of the monitoring points were at an average of 50-70, except for some points in downstream areas, meaning the water can be used for aquaculture.

On the tributaries of Nghinh Tường, Đu and Thương rivers, the water was at a good to a very good level of between 91-100, making it clean enough for daily use.

The water on the Công River has a moderate level of between 51 and 57, which can only be used for traffic waterway activities due to the discharge of domestic wastewater. Some of the monitoring points have been recorded as qualified for irrigation and aquaculture purposes.

Meanwhile, parts of the water surface in the Cầu River basin in Cầu Đào Xá and Cầu Bóng Tối monitoring points were recorded as polluted and have seen no signs of improvement.

The pollution was blamed on the discharge of domestic wastewater as well as wastewater from craft villages in Bắc Ninh Province and Thái Nguyên City.

In the Nhuệ-Đáy River basin – one of the river basins with the poorest water quality in the north, up to 62 per cent of the monitoring points recorded a WQI of below 50, with almost a third of those below 25.

As for the section of the Nhuệ River passing through Hà Nội, pollution continued to occur from Phúc La to Cống Nhật Tựu with the WQI index of between 10-25 due to the discharge of wastewater from craft villages in the city.

Apart from the Hồng (Red), Thái Bình and Đà rivers, the rivers in the inner city remained seriously polluted with a WQI from 12-28 and showed no signs of improvement compared to the same period last year. The water cannot be used for cooking, drinking or production activities. — VNS