Map of Marion County, Indiana with surface soil Hg concentrations and stream Hg concentrations from the White River. The soil Hg peaks coincide with an area just downwind (dominant wind direction is to the northeast) of multiple Hg emission sources, including the largest Hg point source, the Harding Street Station coal-fired electric utility plant (noted by triangle), which emits approximately 62 kg of Hg/yr. The stream sediment values indicate higher concentrations downstream of the soil Hg peak regions, likely the result of funneling of Hg from the various subwatersheds that transport water and sediments to the south /southwest of the county (e.g., Hatcher and Filippelli, 2010).