Mercury concentrations in wetlands associated with coal-fired power plants in Illinois.

摘要

Burning of fossil fuels by coal-fired power plants (CFPPs) is one of the largest sources of environmental mercury in the United States and there have been conflicting reports of local impacts due to CFPPs in the US. Illinois has 23 coal-fired electrical generating plants that may be contributing to elevated environmental mercury concentrations that have contributed to mercury advisories for 13 bodies of water located throughout the state. The objective of the current study is to determine if there is a pattern of total mercury concentrations in sediment and tadpoles collected from ponds located upwind and downwind of 4 coal-fired electrical generating plants in Illinois. Baldwin, Joppa, Newton, and Southern Illinois Power Cooperative (SIPC) coal-fired power plants were chosen for study. Three sediment samples were collected from ponds located 3-5, 8-10, and 13-15 km downwind and from ponds located 3-5 km upwind of each power plant and analyzed for total mercury concentration. Temperature of overlying water (°C), pH, oxidation-reduction potential (mV), and texture were determined for each sediment sample. Bullfrog (Lithobates catesbeiana ) or Green frog (Lithobates clamitans) tadpoles were collected opportunistically from 29 of the 44 ponds chosen for study. Each tadpole was identified to species and Gosner stage, and then weighed (+/- 0.1 g) and measured for total length (+/- 0.1 mm) prior to total mercury analysis. For Baldwin, Joppa, and SIPC power plants, no significant pattern of total mercury could be determined from either sediment or tadpole data. For Newton power plant, total mercury concentrations were significantly greater 3-5 km downwind for sediment, and 8-15 km downwind for tadpoles compared to concentrations at upwind locations. Sediment total mercury concentrations were not significantly correlated with any of the characteristic variables (e.g. pH). Tadpole total mercury was significantly negatively correlated with length and weight, but not significantly correlated with any of the sediment variables. Sediment and tadpole concentrations were not significantly correlated.