"Tracing Mercury's Transit to Coastal Environments"

On a global average, the amount of mercury falling out of the sky has tripled since the Industrial Revolution, primarily because of the burning of fossil fuels. Although this atmospheric deposition has long been considered the key vector for the widespread contamination of freshwater and coastal ecosystems, some scientists are focusing on another potential source: subterranean flows of terrestrial groundwater. A report published in ES&T found that groundwater entering the ocean at two sites on the central California coast injects substantially more mercury, including surprisingly large amounts of methylmercury (MeHg), into coastal waters than local airborne deposition does. Noreen Parks reports for ES&T in the June 17, 2009 issue.