TRACE ELEMENT ANALYSIS OF SOILS SURROUNDING A COAL FIRED POWER PLANT IN SOUTHWESTERN INDIANA

Soils were sampled at 12 sites at various distances and directions from a relatively modern coal fired power plant near the University of Southern Indiana in Evansville, IN. Local wind patterns were analyzed to see which areas were likely to contain aerosols and/or particulate matter from the power plant. The sample sites were chosen to limit the potential of other sources of trace elements, namely agricultural herbicides and pesticides. Once upwind and downwind soil sites were determined, samples were collected, then tested for As, Pb, and Se using graphite furnace Atomic Absorption spectroscopy. Se, a trace element that is found in Illinois basin coal, but is rare in local unconsolidated strata served as the test to proceed with other elemental analysis. Values of Se ranged from 9 ppb to 58 ppb with a strong spatial distribution downwind from the power plant, warranting further investigation. Pb exhibited slightly lower values than Se with minimum and maximum concentrations of 0.6 and 13 ppb respectively. As showed the greatest variability and highest values, with concentrations ranging from 1 to 345 ppb. Samples from sites downwind from the power plant contained higher concentrations of Se, As and Pb, with maximum values of each element occurring a horizontal distance of 5 km downwind from the power plant smokestacks. Most sites show increasing concentration with depth suggesting translocation of clay sized particles and downward movement of water are contributing to mobilization and accumulation of these hazardous elements.