AN ASSESSMENT OF MERCURY EMISSIONS AND HEALTH RISKS FROM A COAL-FIRED POWER-PLANT

Title III of the 1990 Clean Air Act Amendments (CAAA) directed the US Environmental Protection Agency (EPA) to evaluate the rate and effect of mercury emissions in the atmosphere and technologies to control such emissions. In response to this and other forthcoming analyses the US DOE sponsored a risk assessment project at Brookhaven (BNL) to evaluate health risks of mercury emissions from coal combustion. Methylmercury (MeHg) is the compound predominantly responsible for human exposures to atmospheric mercury in the United States, through the fish ingestion pathway. In the BNL study, health risks to adults resulting from Hg emissions from a hypothetical coal-fired power plant were estimated using probabilistic risk assessment techniques. This study showed that the effects of emissions of a single large power plant may double the background exposures to MeHg resulting from consuming fish obtained from a localized area near the power plant. Even at these more elevated exposure levels, the attributable incidence in mild neurological symptoms (paresthesia) was estimated to be quite small, especially when compared with the estimated background incidence in the population.