Response of Surface Water Acidification in Upper Yangtze River to SO2 Emissions Abatement in China

• Published in: Environmental science & technology 2011-04, Vol.45 (8), p.3275-3281
• Main Authors: Duan, Lei, Ma, Xiaoxiao, Larssen, Thorjørn, Mulder, Jan, Hao, Jiming
• Format: Article
• Language: English
• Subjects: Air Pollutants - analysis; Air Pollution - statistics & numerical data; Applied sciences; Characterization of Natural and Affected Environments; China; Continental surface waters; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Monitoring; Environmental Policy; Exact sciences and technology; Hydrogen-Ion Concentration; Natural water pollution; Pollution; Pollution, environment geology; Rivers - chemistry; Sulfur Dioxide - analysis; Water Pollutants, Chemical - analysis; Water Pollution, Chemical - statistics & numerical data; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es1038672

Surface waters in Europe and North America are slowly recovering from acidification following major reductions in emissions of sulfur dioxide (SO2) since the 1980s. In contrast, regions affected by acid rain have been reported to be growing in China. Here we show that the rapid change in surface water chemistry in the 1990s in large areas in Southwestern China, specifically the tributary rivers of the Upper Yangtze River, caused by increasing SO2 emissions, has leveled off. During the 1990s the sulfate (SO4 2−) concentrations in river water increased rapidly and, on average, doubled in only eight years. Simultaneously, calcium (Ca2+) concentrations increased, while pH values decreased. In the following decade (2000s), SO2 emissions stabilized, causing a subsequent stop to the increasing SO4 2− concentrations and pH decline in river water. Although a rapid response to future reduction in SO2 emissions can be expected, a rapid increase of nitrogen (N) emissions could lead to increases in N leaching and delay recovery.