The United States and the People's Republic of China share a common problem: elevated nitrate concentrations in water supplies used for drinking water, according to a recently released report by the U.S. Geological Survey (USGS). While elevated concentrations of nitrate in water have been known to cause illness in babies, there is also indirect evidence that they can cause cancer. Because of the increased use of fertilizers worldwide since the 1950s, drinking water derived from aquifers in both countries have seen increased levels of nitrate, a plant nutrient regulated by the Safe Drinking Water Act in the U.S. and by the Ministry of Water Resources in China.
?On average, similar levels of nitrate were found in both countries in areas where heavy agricultural use of nitrate fertilizers is common,? said the report's author, Joseph Domagalski, a USGS hydrologist. ?However, the highest concentrations were measured in China.?
The Ministry of Water Resources and the USGS agreed to study the ground water quality of a heavily used agricultural region in northern Hebei Province, located southeast of the city of Beijing, and to compare the quality of that water with similar areas in the U.S. The areas studied in the U.S. included the Central Valley of California and the Delmarva Peninsula of Maryland, Virginia and Delaware.
?Despite the fact that the agricultural land in China has been farmed for a much longer time relative to land farmed in the U.S., the patterns of nitrate contamination are similar,? Domagalski said. The reason for this similarity includes the increasing worldwide availability of nitrogen fertilizer since the 1950s as part of the Green Revolution to increase agricultural production worldwide. Heavier use of nitrate fertilizer in China, and well construction techniques that allow for easy infiltration of rainwater or irrigation water, account for some of the higher concentrations there.
A surprising finding was that pesticides were not detected in any of the wells sampled in China. Although it was assumed that similar types of pesticides would be used in both countries, the lower use of these types of chemicals in China probably accounts for the lack of detections in water.
Copies of U.S. Geological Survey Professional Paper 1647, Comparative Water-Quality Assessment of the Hai He River Basin in the People?s Republic of China and Three Similar Basins in the United States, by Joseph Domagalski, Zhou Xinquan, Lin Chao, Zhi Deguo, Fan Lan Chi, Xu Kaitai, L. Ying, Luo Yang, Liu Shide, Liu Dewen, Guo Yong, Tian Qi, Liu Jing, Yu Weidong, Robert Shedlock and Donna Knifong, is available on the World Wide Web as downloadable files (PDF) at http://water.usgs.gov/pubs/pp/pp1647/ or can be ordered by calling 1-888-ASK-USGS.