Letters

Soil Pollution: Urban Brownfields

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Science  16 May 2014:
Vol. 344, Issue 6185, pp. 691-692
DOI: 10.1126/science.344.6185.691-b

China's plans to tackle farmland pollution and improve food safety are to be welcomed (“China gets serious about its pollutant-laden soil,” C. Larson, News & Analysis, 28 March, p. 1415). However, the country faces equally serious urban soil and water pollution.

As a result of unparalleled urbanization over recent decades, many polluting and energy-intensive activities, including steel, coke, pesticide, and chemical industries, have relocated from urban areas to peripheral or rural areas (1). The legacy is more than 5000 brownfields—sites polluted, or potentially polluted, by hazardous substances—in China's major cities (2). A recently released ambitious urbanization plan will move more polluting plants from cities, leaving more brownfield sites (3). Brownfields pose health and environmental hazards in densely populated cities and are obstacles to urban and economic development. Soil concentrations of pollutants, including heavy metals, persistent organic pollutants, and benzene, can be hundreds of times the regulated limits (4). Seepage will also result in groundwater contamination.

Many brownfields have been used for housing. Without adequate survey and remediation of toxic brownfields, construction has already resulted in acute poisoning incidents. For example, workers were hospitalized during construction on sites at former pesticide factories in Beijing and Wuhan (4). Residents of newly built houses are often unaware of pollution beneath their properties. The Guangzhou Asia Games Village site was changed due to soil pollution from fertilizer factories, but housing for local people is being built in the area (5).

The Chinese Premier vowed to declare “war on pollution.” However, government spending on environmental protection and energy conservation decreased by 9.7% between 2012 and 2013 (6). Funding and technology may limit remediation of Chinese brownfields, but information should be made publicly available to raise awareness and facilitate wider participation in brownfield management. Experience from elsewhere, such as the U.S. “Brownfield Act” (7), should be deployed to demonstrate commitment to tackling the growing problem of soil pollution.

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