BEIJING, Aug. 19 (Xinhuanet) -- China's fresh water lakes have been hit by high levels of pollution, affecting their ecology and water quality.

Eutrophication, which results in excessive algae growth, has become a persistent problem across the country. Our reporter Ning Hong went to Chaohu Lake in east China’s Anhui Province to see what’s being down to clean up the pollution.

Since the 1980s, eutrophication in many of the country’s lakes has been getting worse.

The last field test by Anhui Agriculture University shows that agricultural activity around the lake is the primary cause.

The area around Chaohu Lake is one of China’s major grain production regions. Researchers think the over use of fertilizers has left a lot of phosphorus and nitrogen in the water system. These elements have become the major source of eutrophication.

Researchers from Anhui Agricultural University are trying to find out how fertilizers affect water quality.

It turns out that the level of nitrogen doubled after the use of fertilizer. Through a canal and pumping station, the highly polluted water is directly washed into the lake.

Chemical fertilizers are widely used, which spreads the pollution everywhere. And after decades of accumulation, eutrophication in lakes is no surprise. In order to reverse that tide, farming methods need to be changed.

(Source: cntv.cn)