LEBANON, N.H. -- Dartmouth Medical School (DMS) researchers have discovered industrial pollution sites in northern Mexico that have higher than ever before reported levels of heavy metal contamination. Smelters in Torren and Chihuahua constitute a serious environmental threat to people living near these industries, according to a report in the April issue of Environmental Health Perspectives, the monthly journal of the National Institute of Environmental Health Sciences.
"This is one of the most heavily contaminated residential areas in the Western Hemisphere and it has never been studied," says James Sargent, MD, a principal author of the study, and a pediatrician at Children's Hospital at Dartmouth at Dartmouth-Hitchcock Medical Center and Dartmouth Medical School.
In July 1995, roadside dust samples were collected from residential areas within 2,500 meters of smelters and refineries located in the cities of Torren, Monterrey, and Chihuahua. Smelters and refineries are known to be potential sources of heavy metal contamination such as arsenic, cadmium, and lead. These cities have dry, dusty climates with residential areas lacking any substantial ground cover such as grass or bushes. Without adequate ground cover, heavy metal pollutant-laden dust is more ubiquitous and airborne, increasing the likelihood that it will be ingested or inhaled.
In all three cities, heavy metal concentrations exceeded maximum acceptable levels established by the EPA for cleanup at U.S. Superfund sites. "Previous studies of heavy metal exposure in Mexico have focused primarily on lead in gasoline and household ceramics," said Sargent. "Other environmental contaminants such as cadmium and arsenic have largely been ignored."
Based on data from previous studies, Sargent estimates the average blood
lead levels in children living within 1 mile of the Torren smelter would
Contact: Laura Carter
Dartmouth Medical School