The Dong Nai watershed is on red alert, said an official of the Environmental Protection Department under the Ministry of Natural Resources and Environment.
Be River, Sai Gon River, Vam Co River and Thi Vai River in Dong Nai, Binh Phuoc and Lam Dong Provinces are tributaries of Dong Nai river.
|Dong Nai River (Photo:U.Phuong)|
The surface water of Dong Nai River in the downstream in the section from Thien Tan Water Supplying Plant to Long Dai in the province of Dong Nai has become polluted by organic and suspended solid substances.
The pollution levels exceed the warning level by 3-9 times. Also the lead density over the country’s standard of pollution level. Due to its high salt content, it can not be used as water for domestic purposes or for planting.
High concentration of coliform, which is from 3 to 168 times higher than the permitted standard. More than 10 km long section of Thi Vai River, the most seriously polluted area in the basin, is called the dead river.
The water in the section is polluted with organic substances with blackish brown color and stinking odor during both high and low tide.
Some sections even have dissolved oxygen values of zero, biological are unable to survive.
The mercury concentration in Vedan and My Xuan Port in Thi Vai River is discovered to be 1.5-4 times higher and the zinc value is 3-4 times higher than the permitted standard, according to a survey carried out by an environmental research department.
Many sources cause pollution in Dong Nai River like waste water from industrial zone, mining activities, craft villages, domestic, hospitals and agriculture. Domestic and industrial waste water contribute the biggest share with very high volume of pollutants.
There are around 60 industrial parks in the Dong Nai basin. However, only one third of them have water treatment systems. The rest let out directly into rivers.