Lead challenges China's children. (Lead).

A recent study in the Chinese city of Shenzhen has revealed excessive blood lead levels in two-thirds of the city's children, reflecting what many believe is a problem throughout Chinas industrialized cities. Researchers with the Chinese Medical Association found that 65% of the 11,348 schoolchildren they tested had concentrations above the safe limit of 10 [micro]g/dL set by the World Health Organization, according to an article in the 19 June 2002 Los Angeles limes on the unpublished study.

According to Anne Platt McGinn, a senior researcher with the Worldwatch Institute who specializes in environmental health, the problem in China is especially acute in the rapidly developing urban areas. Studies support her claim. One, published in the January 2002 China Medical Journal, showed that 18% of children immigrating from mainland China to Hong Kong had blood lead levels greater than 10 [micro]g/dL. Another study, published in the 1 September 2001 issue of Environmental Research, found concentrations over 10 [micro]g/dL in 27% of children aged 1-5 years in Wuxi City.

Excessive blood lead is associated with nervous system impairment, including cognitive difficulties and behavioral problems. At high enough exposures, lead can stunt children's growth and cause permanent brain damage and mental retardation. Children are more vulnerable to lead poisoning than adults because they breathe air closer to the ground, where lead concentrates. Very young children also are more likely to put lead-contaminated objects in their mouths.

Throughout most of the last half-century, environmental protection in China was overlooked as the country focused on industrialization. In the last decade, though, the consequences of uncontrolled growth have become impossible to ignore as pollution has fouled Chinas water and air.

McGinn and others believe that Chinese children's blood lead levels are near their peak and should soon drop as China continues to clean up its polluted environment. "Certainly I think over time lead will decrease," says Xiaobin Wang, an associate professor of pediatrics and maternal and child health at Boston University Medical Center, and a native of China. "There is increasing public awareness to improve the environment."

One measure China is taking to protect children from lead is a phaseout of leaded gasoline. Chinas adoption of unleaded gas has been spotty, according to the Times article. "My understanding is that leaded gas is not being produced in China," says James Rochow, director of international programs for the Washington, D.C.--based Alliance to End Childhood Lead Poisoning. "But it seems leaded gas is available, especially in the far western provinces." Government officials say the country is working to eliminate it altogether. "I think it's been phased out in many big cities," says press secretary Sun Weide of the Chinese embassy in Washington, D.C. Removing lead from gasoline drastically reduced lead exposure in the United States. Since the 1970s, American children's blood lead levels have dropped 80%, to a geometric mean of 2.0 [micro]g/dL.

In China, though, it might take more than a switch to unleaded. A report from the Shanghai Second Medical University published in the October 1999 issue of the China Medical Journal showed that the blood lead of children living in Shanghai did not drop as much as expected after the city phased out leaded gas. The authors suggest that exposure continued from industrial emissions. Another lead source cited by McGinn is computer and electronic waste imported from North America for dismantling in China [see "e-Junk Explosion," EHP 110:A188-A194 (2002)]. The equipment is broken down with few health or environmental protections, says McGinn.

Whatever the source, the Chinese government appears serious about reducing children's risk. Government officials, alarmed by results of the Shenzhen and other studies, plan to launch a nationwide lead survey of 8-10 million children, according to the Times article. "People are making great efforts to improve the environment," Wang says. "There'll be tremendous changes."