The water from supply companies in east China's Wuxi City was again potable on Sunday afternoon, ending a water crisis caused by the bloom of blue-green algae which polluted the city's water source.

(File photo: Taihu Lake)

The quality of water from all tap water companies in Wuxi of Jiangsu Province is stable and has met the standards for drinking water, said the local health authorities.

But urban residents in Wuxi, with a population of two million, still depend on bottled water for cooking and drinking as certain polluted water still remains in transmission pipes, they said, calling for residents to let the remaining water out for clean tap water.

Tap water supply for the city was halted on May 22, when its major source -- the Taihu Lake, started to stink with a blue-green algae bloom, an increase in the number of algal cells to a point where they discolor the water, form scum, produce unpleasant tastes and odors, affect shellfish and fish populations or otherwise create a nuisance and seriously reduce water quality.

Experts finally succeeded in dispelling the stench produced by the blue-green algae at Taihu Lake with potassium permanganate, an oxidant. Workers also added active carbon powder at treatment plants, and water was diverted from the Yangtze River to dilute the lake water.

The health authorities will continue to monitor the water quality in the next few days to ensure its safety for drinking, according to the Wuxi health bureau.

Taihu Lake, which was once a scenic attraction famous for its aquatic life, including white bait, shrimp, lily, and water chestnuts, has been heavily polluted as a result of industry, agriculture, and domestic waste.

The Wuxi city government said it has decided to strengthen efforts in treating the lake's pollution after the algae-pollution crisis.

(Xinhua News Agency June 4, 2007)