Selected Water Quality Attribute Analyses of Infiltrated Waters from Reforested Loose-Graded Mine Spoils in Eastern Kentucky

A study of various types of loose-graded mine spoils with regards to water quality and forest establishment at the Bent Mountain surface mine, Pike County, Kentucky, has been ongoing since 2005.  Six research plots consist of two replicates of brown weathered sandstone, gray unweathered sandstone, and mixed brown sandstone, gray sandstone, and shale. The spoils were “end dumped” in large, parallel rows 2-3 meters deep and are one acre in area.  Each plot is isolated by a 2.5 meter buffer zone and drains into its own sample monitoring station by means of lysimeters and PVC pipes.  Water-quality measurements (electrical conductivity, pH, chloride, sulfate, magnesium, calcium, potassium, sodium, nitrate, ammonium, total organic carbon, and dissolved organic carbon) have been collected for the past three growing seasons. Recently, tests on two significant water quality attributes of spoil waters have involved analyzing source of elevated sulfate concentrations (and elevated pH) in brown sandstone spoil waters and detection of Phytophthora cinnamomi, an exotic forest pathogen that causes dieback and may affect success of founder species of hybrid American Chestnut (Castanea dentata).PHREEQC geochemical modeling will be used to analyze aqueous speciation of sulfur with respect to time, tailing media, and vegetation. Variance of δ³⁴S ratios between plots will be analyzed to possibly determine source of sulfate minerals of mine spoils. To detect Phytophthora cinnamomi in spoil waters, infiltrated waters will be analyzed by exclusion on a filter membrane for Phytophthora-sized particles such as mycelial fragments or reproductive structures. The membranes will be plated on Phytophthora-selective growth medium and duplicates will be subjected to DNA extraction and PCR.  Further analyses of selected water quality attributes by geochemical modeling and filtration methods may provide further evidence as to the most appropriate mine spoil type for reforestation of surface mines in Appalachia.