Chinese experts have begun to monitor the quality of the Songhua River, which flows into Russia, in line with an international treaty on environmental safety and public health.

The project, officially launched on Monday in Heilongjiang Province in northeast China, will trace 12 persistent organic pollutants (POPs) until July 2009 to determine the sources of pollution and the environmental and human impact, the provincial environment protection administration said.

The results are expected to give local and central authorities better knowledge of the POP situation and develop relevant policies, said Yu Lifeng, an official with the Ministry of Environment Protection.

Local experts will survey all major tributaries of the Songhua River and more than 6,000 lakes and reservoirs along the valley, which covers more than 800,000 ha, according to the administration.

Provincial authorities involved with public security, finance, commerce, science and technology, health, quality inspection, civil affairs and agriculture will work together in the campaign.

The 12 POPs, mainly hazardous pesticides and industrial chemicals such as aldrin, DDT, hexachlorobenzene and dioxins, can damage the nervous and immune systems, cause cancer and other health problems. It takes these chemicals years to degrade.

According to the United Nations Environment Program, everyone on Earth has traces of POPs in their body.

The Songhua River program is China's first POP elimination project in a major river valley since the Stockholm Convention on POPs came into effect in 2004. The convention has 151 signatories.

Many other regions across China, including Guangdong Province and the cities of Shanghai and Chongqing, plan similar projects.

China has a draft plan to phase out POPs by 2016 at an estimated cost of 34 billion yuan (4.97 billion U.S. dollars).

The Songhua River, the largest tributary of the Heilongjiang River, was contaminated after a blast at a chemical plant discharged a spill of about 100 tons of benzene in 2005.

The leak indicated that the toxic chemical could persist in the water.