Attenuation of contaminants of coal pile leachate by interaction with subsoil

Increased use of coal as energy source has resulted in its greater outdoor storage at electrical generation sites. Coal pile runoff (CPR) with its high concentrations of Fe, Al and sulfate leaches into subsoil and may adversely affect the quality of groundwater. During the summer, 1995, this study was conducted to determine the removal of CPR contaminants by subsoil around D-area electric plant at Savannah River Site (SRS). Groundwater samples from five monitoring wells were analyzed for physical and chemical parameters. Hydrolab Surveyor, TOC Analyzer, Dionex Ion Chromatograph and ICP-ES instruments were used for analysis. Results showed appreciable removal of CPR contaminants, sulfate, Fe, Al, Cr, Mn and Ni by the upper subsoil near the pile. The reductions in the concentrations of major contaminants in the distant wells relative to the near wells were from 12,947 to 1293 mg/L for sulfate, from 3.138 to 42 mg/L for Fe, and from 593 to 119 mg/L for Al. The study revealed the capacity of soil system to retain toxic elements of CPR leachate, which may lead to remedial actions.