By Cao Li (China Daily)
Updated: 2007-09-06 09:15

SHANGHAI: Chaohu Lake, one of the city's major water sources, has become highly polluted after torrential rain in eastern Anhui Province.

Three of the nine rivers that border the lake were reportedly heavily contaminated, while the water quality of the other six was described as mildly polluted or intermediate.

An official with the water environment protection office under Anhui Province, who only gave his surname Lu, said flooding caused the contamination.

"Floods that swept the area in August have caused fertilizers that were not absorbed in nearby fields to enter the lake and thereby increased phosphorous levels in the water," he said.

"Chaohu Lake has low motility and has not been able to sufficiently dilute (the chemical)."

Lu said the city of Chaohu, which is on the east side of the lake, was not affected by the pollution. Although it depends on the lake for its water supply, he said the intake point for the city's water supply was far away from the worst of the contamination.

He said local government officials haven't found an effective measure so far to solve the problem.

"The lake is not deep and mostly enclosed, making dilution more difficult," he said. "And we have not invested enough money (to deal with the situation)."

Duan Liping, from Chaohu, said tap water had a bad smell about two or three weeks ago but improved after it was treated with chemicals.

"We've got used to pollution," she said.

The lake became polluted in the 1980s when nearby cities began to develop, Lu said.

"Factories were established and waste was not properly handled before releasing it into the lake."

"It was only after 1995 the city began to process domestic sewage."

Lu said the provincial capital Hefei changed its water supply from the lake to the Yangtze River because of pollution.

He said there had been efforts to clean the river and there had been improvements, "but there is still much to be done."