02.11.2007 - Press release
Swiss and Chinese scientists give voice to the Yangtze River
On Friday, 2 November, the Swiss Agency for Development and Cooperation (SDC) played host to an unprecedented event: Swiss and Chinese scientists jointly presented the results of their water quality survey of the world’s third largest river. The water quality survey was part of the Yangtze Freshwater Dolphin Expedition conducted under the auspices of the baiji.org Foundation. The scientists’ diagnosis dispels a major fear: the Yangtze River is not dead, – at least not in terms of the water’s chemical composition. Less fortunate was the goddess of the river, the freshwater Baiji Yangtze dolphin. This twenty million year-old species is now extinct.It is a colossus, a colossus with feet of mud. It is 6,300 km long. 400 million people live along its banks. It has over 700 tributaries. It is the source of water for 40% of Chinese territory and 70% of the country's rice fields. 25 billion tonnes of waste are poured into it each year. This is the Yangtze River, the “Long River”, one of the world’s longest rivers and also considered to be one of its most polluted. Is there any hope remaining along this immense river? The response from researchers is mixed. A year after exploring the waters of the Yangtze, the joint Swiss-Chinese scientific expedition delivered the final results of its study at a conference held at the SDC’s offices in Bern.
Outcome less alarming than expected
Under the patronage of the Chinese Ministry of Agriculture and with the support of the Société générale de Surveillance (SGS), Pictet Bank and the SDC, the Zurich-based baiji.org Foundation conducted a unique expedition. For the first time, researchers from the Swiss Federal Institute of Aquatic Science and Technology (Eawag) and the Wuhan Institute of Hydrobiology worked together to examine the waters of the Yangtze River. Their diagnosis is less alarming than expected. While the pollution level is enormous, the concentration of pollutants remains comparable with that of other rivers given the dilution effect caused by the enormous rate of water flow. August Pfluger, expedition organiser and Director of the baiji.org Foundation, summed up the situation in this way: "The ecosystem of the Yangtze can be saved if China intensifies its activities in water protection now."
Agriculture, the main culprit
In the 1,750 km-long stretch between the Three Gorges Dam – currently under construction – and Shanghai, Swiss and Chinese scientists collected hundreds of water and sediment samples for analysis in the laboratories of Eawag in Switzerland and SGS in China and Australia. First major observation: one of the main sources of pollution in the river is agriculture, which uses an excessive amount of mineral fertilizers that have found their way into the river. This explains why the quantity of nitrogen in the Yangtze has doubled over the past twenty years. In contrast, the phosphate concentration remains low.
Heavy metal concentrations lower than in the Rhine thirty years ago
“The water quality of the Yangtze is comparable to that of other large rivers in the world,” explains our geochemist Beat Müller, who is in charge of the study at Eawag. “The current heavy metal concentrations in the Yangtze remain about two to eight times smaller than in the Rhine 30 years ago, at the peak of its pollution.”
This does not mean that the situation is not dire. The average heavy metal concentration may be low, but this is mainly due to the enormous flow of water in the Yangtze river system – the world’s third largest after the Amazon and the Congo. 31,900 m3 of water per second pour from the Yangtze River into the East China Sea, and concentrations of pollution have reached dramatic proportions in this delta. Each day, 1,500 tonnes of nitrogen and 4.6 tonnes of arsenic wash along the coastal waters. “The more nitrate enters the sea, the more the blue-green algae grow, mainly at lower sea levels, and the oxygen becomes scarce,” said Beat Müller
The heavy metals also find their way into the water consumed by hundreds of millions of people, into rice and corn fields irrigated by the river and into two-thirds of the fish that the Chinese place on their dinner table.
A goddess that succumbed to modernisation
Despite this, no link could be established between the quality of water of the Yangtze and the extinction of the freshwater river dolphins, the baiji, nor the rapid decline in the finless porpoise population from several thousand at the turn of the century to a few hundred today. The disappearance of the dolphins and the threat of extinction faced by these finless porpoises can be traced to a combination of factors – pollution is only one of the causes of the rapid and widespread degradation of these animals’ natural habitat. Industry, agriculture, growing waterway traffic, noise pollution and fishing methods are all responsible for the death of the baiji which, for twenty million years, was the goddess of the Yangtze.
What does the future hold for the Yangtze River?
Pressures on the Yangtze will continue to intensify with the growth of industry in China, a rising standard of living, irrigation systems, the production of electricity and the diversion of enormous quantities of water towards the Yellow River basin to the north. To reverse this trend, China needs to urgently adopt similar rehabilitation and development programmes that were used to improve the quality of rivers in Europe only a short time ago. While it is too late to save the baiji, other species such as the finless porpoise and the Chinese sturgeon still have a chance to survive – provided we give them this chance.