Mercury from power plants: A probabilistic approach to the evaluation of potential health risks

Estimating the impacts of mercury (Hg) power plant emissions on the environment and human health involves the prediction of chemical concentrations in the different environmental media and the foodchain. As calculations show the ingestion pathway to dominate Hg risk, the reliable characterization of the processes influencing Hg concentrations in environmental media other than air is of particular importance. In this context, we present and implement an approach for the evaluation of Hg multimedia risks associated with power plant emissions. The approach is based on the investigation of four critical components influencing Hg ingestion risk: (1) Hg deposition; (2) hydrologic environment; (3) Hg uptake by fish; and (4) Hg uptake by vegetation. To capture the variability in the conditions affecting Hg risk, the problem is handled in a probabilistic way, where the influential parameters are assigned probability distributions or possible value ranges that cover a wide spectrum of emission possibilities and environmental conditions. Particular emphasis is given to the aquatic environment.