High levels of algae in east China's Taihu Lake are causing increasing concern for experts and residents. 

"The severe eutrophication of the lake is likely to cause a blue-green algae bloom, which will endanger both biodiversity and the health of local residents," Chen Feizhou, a researcher with the Taihu Laboratory for Lake Ecosystem Research under the Nanjing Institute of Geography and Limnology, told China Daily.

Eutrophication is a process whereby water bodies, such as lakes, receive excess nutrients that stimulate excessive plant growth. Statistics released in a recent forum held in Shanghai on Taihu Lake pollution management show that the eutrophication rate of the lake is as high as 70 percent.

According to experts, the eutrophication is caused mainly by untreated industrial, household and agricultural discharges. "These uncontrolled discharges have brought excessive nitrogen, phosphorus, microcystins and other toxic organic materials into the feeder rivers, which is the main reason for the increase of eutrophication," said Chen.

Research by Zhu Songquan, another expert working with the institute, found that the species of fish have decreased from 103 in 1960s to 48 in 2004.

Covering an area of 2,400 square kilometers, Taihu Lake, the third largest freshwater lake in China, currently serves more than 40 million people living in Shanghai and east China's Jiangsu and Zhejiang provinces for drinking water, flood control, shipping, waste disposal, fisheries, and farming.

"We drank the water from Taihu Lake without any purification in the early 1980s. Now, it cannot be drunk even after treatment," sighed Zhang Jiang, a local resident in Wuxi, a city on the northern banks of the lake.

(China Daily November 1, 2005)