Villagers row a boat on the algae-filled Chaohu lake in Hefei, East China's Anhui Province, June 5, 2008. Recently, blue-green algae has been discovered in the west part of Chaohu Lake, which is China's fifth largest body of fresh water and the drinking water source for about 320,000 people. [Xinhua]

A worker uses water pump to clear algae in Chaohu lake in Hefei, East China's Anhui Province, June 5, 2008. Recently, blue-green algae has been discovered in the west part of Chaohu Lake, which is China's fifth largest body of fresh water and the drinking water source for about 320,000 people. [Xinhua]