CHINA:China's mighty Yangtze River has been irreversibly polluted, a new report by top Chinese and foreign scientists has shown. More than 600km of China's longest river is critically polluted and sections such as the Three Gorges Dam reservoir have been irretrievably poisoned by pesticides and sewage.
The study, by the Chinese Academy of Sciences, WWF and the Yangtze River Water Resources Commission, paints a grim picture of the Yangtze, which accounts for 35 per cent of China's total freshwater resources.
Pollution, damming and too many boats have caused a dramatic decline in its aquatic life.
Last December scientists said they feared the white-fin dolphin, or baiji, which swam in the river for 20 million years, had become extinct. But the situation is so bad that it's not just rare species that are struggling - even common species such as carp are in peril.
"The impact of human activities on the Yangtze water ecology is largely irreversible," said Yang Guishan, a Chinese Academy of Sciences researcher and one of the report's editors.
"It's a pressing job to regulate such activities in all the Yangtze drainage areas and promote harmonious development of man and nature." Cities along the river, including giant conurbations like Shanghai and Chongqing, discharge at least 14.2 billion tonnes of polluted water every year, 42 per cent of China's total.
It's hard to overstate the importance of the Yangtze to the Chinese national psyche - the Chinese call it simply chang jiang, or long river - as well as its economic importance as a water supply and a shipping route. It runs 6,300km through nine provinces from western China's Qinghai-Tibet plateau to the East China Sea.
The report says that nearly 30 per cent of the river's major tributaries, including the Minjiang, Tuojiang, Xiangjiang and Huangpu rivers, are now seriously polluted.
Pollution is playing havoc with fishing. The Yangtze's annual harvest of aquatic products dropped from 427,000 tonnes in the 1950s to about 100,000 tonnes in the 1990s, the study says.
The river regularly bursts its banks and floods surrounding areas with spectacular results. One of the main reasons for building the Three Gorges Dam, the world's largest water storage facility, was to regulate the river's level. However, flooding is liable to get worse. "Flood control remains an arduous task along the Yangtze, given the rising temperature and frequent occurrences of extreme weather over the last 50 years," said Mr Yang.
Although the dam has reduced flood risks in the middle reaches, the risk of flooding remains high in the lower reaches, he said.
It is only in the past couple of years that China has started to pay attention to the environmental downside of its breakneck economic growth of the past quarter century.
Premier Wen Jiabao told the National People's Congress last month that economic growth had to be balanced with environmental protection. People are unhappy about the filthy air in the cities and the damage wrought by pollution, and there are fears it could prove politically destabilising.
At a forum on protecting the river, minister Wang Shucheng, China's top official on water resources, proposed limiting the development of the Yangtze and Dongting Lake to a sustainable level of around 60 per cent of the catchment area, compared to more than 90 per cent now.