The Muck Is Coming.(The World According to Alan Greenspan)(Environment)(algal blooms in China's lakes and rivers)

Byline: Jonathan Adams; With Wang Zhenru in Beijing

Something is out of whack in China's lakes and rivers. Algae blooms are making fresh water undrinkable.

Zhang Zhengxiang jabs his finger angrily over the water, which shimmers a bright, fluorescent green. That's the color of the toxic algae that now clogs large swaths of the high-altitude, freshwater Lake Dianchi for most of the year. The water may be pretty from a distance, but it's a sign that the lake is profoundly sick. Before the early 1980s, says Zhang, this was a swimming area, and shrimp from the lake were a prized delicacy at high-end restaurants in Shanghai, Beijing and elsewhere. Now the lake's shrimp are inedible, and the toxins in the algae make swimming a decidedly unpleasant experience. Zhang yanks up his trouser leg to show the rash left on his ankles from a recent wade into the once pristine waters. "If you go in, your skin will turn red immediately," says a disgusted Zhang.

China's breakneck economic development has resulted in the world's fastest-growing toxic-algae problem. On the coasts, monster blooms of algae -- the "red tides" -- have already made many areas a misery of muck, devastating fisheries and tourism. However, toxic blooms on China's freshwater lakes and reservoirs are even more worrisome, since they can have an impact on critical tap-water supplies. This summer the worst-ever such blooms were a media focus in China, as one lake and reservoir after another fell victim to poisonous goop. In May a blue-green algae bloom on Lake Tai caused mass panic when it contaminated the water supply of 2 million residents of the city of Wuxi, in Jiangsu province. Huge blooms were also reported on Lake Chao, further inland. And in late July, 100,000 residents in the northeast city of Changchun went waterless when a toxic bloom appeared on a key reservoir.

Rogue algae are just one symptom of the environmental price China is paying for its roaring economy. Rapid growth has meant a surge in nitrogen and phosphorus pumped into the nation's waterways, which has fed both ocean and freshwater blooms. China and other developing countries are increasingly dependent on freshwater lakes and reservoirs to supply drinking water to swelling populations. Toxic algae can render water undrinkable, cause lung and liver problems and turn shellfish into a deadly dish for humans.

Of course, most algae are harmless. In fact, they produce much of the oxygen necessary for animal life on earth, absorb carbon dioxide, decompose into critical fossil fuels and are the base of marine food chains. Some algae are naturally toxic to humans and other animals, possibly to ward off predators, scientists speculate. Pollution has fattened the algal blooms to unprecedented proportions. Whereas red algae of the ocean feast on nitrogen, the blue-green algae that inhabit fresh water munch on phosphorus -- plentiful in fertilizer runoff from farms, factory waste and untreated sewage. Both types of algae can also feed on nutrients from the atmosphere -- in acid rain, for example. The link between pollution and algae was speculative until the early 1990s, when the former Soviet Union halted farming subsidies to the Black Sea area. Algae blooms declined dramatically.

The ground zero of China's toxic-algae problem is Lake Dianchi, in the southwestern Yunnan province. The situation is so bad that the nearby city of Kunming is now forced to gets its drinking water from upstream reservoirs instead of the lake. For at least five years ...