The water quality at China's Taihu Lake remained stable and no algae outbreak would happen in the near future, the water resources authority said on Wednesday, one year after the algae-choked lake turned nearly one million residents' tap water undrinkable for about 10 days.

"The water quality at the lake and its source remains stable," said Ye Jianchun, chief of the Taihu Basin Authority of China's Ministry of Water Resources.

The indices of algae-related chemicals, such as ammonia and nitrogen, were decreasing while the water channeled from the Yangtze River helped accelerate the water flow and thus hampered the algae growth, he added.

The lake, China's third largest body of freshwater, suffered from an algae outbreak at the end of May last year, affecting a large number of residents in Wuxi City.

According to the latest statistics, 92 percent of the lake was at a moderate level of nutrient enrichment, which means the algae would not endanger the water quality and no algae outbreak would happen in the near future, Ye said.

Blue-green algae, which exists widely in water bodies and is not harmful itself, grows easily in polluted water with a high concentration of nitrogen and phosphorous and a temperature of around 18 degrees Celsius.

An excess of blue-green algae removes oxygen from the water, killing fish and other aquatic life, which then decay and release toxin.

No large areas of algae had been spotted in the lake and water supply to neighboring cities was normal, Ye said.

About 30 million people in Jiangsu and Zhejiang provinces and Shanghai rely on Taihu Lake as a drinking water source.

(Xinhua News Agency May 29, 2008)