In spite of ten years of treatment costing billions of yuan, the pollution in Taihu Lake continues to worsen. The 33.5 million people living around Taihu will probably have to wait another decade to drink clean water from the country's third-largest freshwater lake.

Covering an area of 2,400 square kilometers in east China, Taihu Lake is a major source of drinking water for people living in Shanghai and east China's Jiangsu and Zhejiang provinces.

The Taihu Lake basin accounts for about 3 percent of the country's land area and 8 percent of its population. Historically a rich and fertile area, it has become one of the most populous and prosperous regions in the country.

But tremendous economic growth and the huge population of the area are putting the lake under increasing environmental pressure, resulting in deteriorating water quality in recent years.

During the past ten years, a number of projects have been completed to curb the flooding of Taihu Lake, Vice Minister of Water Resources Zhai Haohui said recently at a high-profile seminar in Shanghai. These projects established a framework for flood control and the utilization of water resources.

The Ministry of Water Resources (MWR) reports that the first phase of Taihu Lake projects have produced 15.8 billion yuan (US$1.9 billion) in economic benefits, two-and-a-half times the original investment.

"For example, these projects played an important role in combating the massive flooding of Taihu Lake basin in 1999, saving 9.2 billion yuan (US$1.1 billion)," said Sun Jichang, director of the MWR's Taihu Lake Basin Administration Bureau.

During the Taihu seminar held on December 3, Zhai pledged that people living in the area will be able to drink clean water from the lake by 2015.

However, experts say that the quality of the lake continues to deteriorate despite more than a decade of effort from both the central government and local authorities. Flood control standards are still low and the pollution of the lake remains serious.

The lake's environmental problems include accelerated eutrophication, or aging, caused by nitrogen and phosphorus enrichment. These materials cause an overgrowth of algae and further deterioration, including oxygen depletion. The lake is probably also contaminated with potentially toxic substances originating from increased agricultural, domestic and industrial activities.

The State Environmental Protection Administration (SEPA) has been closely monitoring Taihu's water quality, using 110 manned and three automatic surveillance stations scattered throughout the entire lake area.

One of the basic causes of the pollution lies in sewage treatment measures lagging far behind the rapid social and economic development of the Yangtze River delta.

In the early 1990s, experts estimated that the annual industrial sewage entering the lake would reach 540 million tons and household sewage would reach 320 million tons. Spot checks conducted in 2000 indicated that total sewage surpassed 5.3 billion tons.

According to Sun Jichang, only 30 percent of the household sewage is treated before being dumped into the lake. Gao Erkun of the MWR added that standards and treatment capacity for sewage and wastewater have not been able to meet actual requirements.

SEPA officials said by 2005, plants in the Taihu Lake region will have the capacity to treat 2.2 million tons of sewage per day, nearly 30 percent more than the 1.7 million tons per day required by the 10th Five-Year Plan (2001–05). A total of 243 projects will be constructed to treat wastewater and rubbish, remove silt and reduce contamination from farming and ships. These projects will cost 21.9 billion yuan (US$2.6 billion).

But even if all the wastewater produced in this region is treated in accordance with current standards, it still exceeds the capacity of the basin, Sun said.

The people and enterprises who have benefited from the region's industrialization in the past two decades now have to pay for the treatment of wastewater and rubbish.

Under the auspices of the State Council, some cities in the region have been seeking water resources through cross-regional transmission.

Cities like Suzhou, Changzhou and Wuxi that are neighbors of the Yangtze River have utilized river water to drive their rapid economic development for many years.

During the past three years, the Taihu Lake area borrowed more than 6 billion cubic meters of water from the Yangtze, half of which flowed into the lake itself.

But experts warn that a reasonable and cautious attitude must be adopted with regard to cross-regional water transmission.

"No doubt, the quality of the Yangtze and Qiantang rivers is better than that of Taihu Lake," said Chen Jiyu, an academician with the Chinese Academy of Engineering. "However, it should be noted that these rivers themselves are suffering from increasingly serious pollution."

The fundamental way to improve the quality of the lakes and rivers is to solve the pollution issue as well as adopting measures to save water, Chen stated. 

(China Daily December 17, 2004)