US EPA: Mercury Study Report to Congress - Vol. 4 - AN ASSESSMENT OF EXPOSURE TO MERCURY IN THE UNITED STATES
EXECUTIVE SUMMARY Section 112(n)(1)(B) of the Clean Air Act (CAA), as amended in 1990, requires the U.S. Environmental Protection Agency (U.S. EPA) to submit a study on atmospheric mercury emissions to Congress. The sources of emissions that must be studied include electric utility steam generating units, municipal waste combustion units and other sources, including area sources. Congress directed that the Mercury Study evaluate many aspects of mercury emissions, including the rate and mass of emissions, health and environmental effects, technologies to control such emissions, and the costs of such controls. In response to this mandate, U.S. EPA has prepared an eight-volume Mercury Study Report to Congress. This document is the exposure assessment (Volume IV) of the Mercury Study Report to Congress. The exposure assessment is one component of the risk assessment of U.S. anthropogenic mercury emissions. The analysis in this volume builds on the fate and transport data compiled in Volume III of the study. This exposure assessment considers both inhalation and ingestion exposure routes. For mercury emitted to the atmosphere, ingestion is an indirect route of exposure that results from mercury deposition onto soil, water bodies and plants and uptake through the food chain. The analyses in this volume are integrated with information relating to human and wildlife health impacts of mercury in the Risk Characterization Volume (Volume VII) of the Report.