Shanghai Daily / national / 2007-09-17
The pollution in lakes in southwest China’s Yunnan Province, some of which have already seen several blue algae outbreaks, is actually getting worse, researchers and lake protection experts say.
“Urban population, agriculture and industrial use are guzzling most of the water resources, particularly in the densely-populated central areas of the province. The portion of water that should have been spared to maintain the local ecology has been reduced to the lowest possible amount,” said Ma Hongqi, a veteran expert with the Chinese Academy of Engineering.
Plateau lakes like Dianchi Lake, near Kunming, capital of Yunnan, have been shrinking and are being suffocated by a massive influx of pollutants, he said.
In 1999, about 58 million cubic meters of untreated waste water was poured into the Dianchi. The figure nearly doubled to reach 97 million cubic meters in 2004 and is still rising, said Guo Huiguang, former director of the provincial environmental sciences research institute.
The Dianchi, covering more than 300 square kilometers, started to suffer from blue algae blooms in 1999 and the latest blue algae outbreak this year has forced Kunming to replace the lake with a reservoir as its source of drinking water for its 1.5 million residents.
“We have been seeing a rise in phosphorous substances and chemical oxygen demand (COD), a measure of water pollution, in the lake, and the chances of algae bloom outbreaks are still very high,” Guo said.
Declining water quality is also being seen in Xingyun, Qilu and Yilong lakes, which, combined, cover more than 100 square kilometers.