ETSU undergraduate student, Melissa Magno, receives Martin L. Stout Scholarship

ETSU Geosciences undergraduate student, Melissa Magno, receives Martin L. Stout Scholarship from AEG (Association of Engineering and Environmental Geosciences).

Physicochemical Characteristics and Spatial Distribution of Heavy Metals in Soils Near an Abandoned Mine-Complex in Bumpus Cove, TN 

Magno, Melissa, East Tennessee State University, zmam67@etsu.edu; Arpita Nandi, nandi@etsu.edu; Ingrid Luffman, luffman@etsu.edu 

Generally, mining activities increase heavy metal concentrations in soils by producing waste rock, tailings and slag. Un-reclaimed abandoned mine sites may accumulate heavy metals in soil and threaten environmental and public health. Determination of soil physicochemical properties’ role in the spatial distribution of metals in soil is essential to monitor environmental pollution. Bumpus Cove, once a rich mineralized district of eastern TN, comprises ~47 abandoned, un-reclaimed mines permanently closed in the 1950s. Mineral deposits include primary sulfide deposits, and secondary oxidized deposits within the residual clay. The 0.67 km2 study area encompasses 7 known abandoned Pb, Zn, and Mn mines. This study evaluated the relationships between soil physical (texture, moisture content, bulk density), chemical (cation exchange capacity [TEC], percent base saturation, pH, total carbon content [TOC]), and heavy metal (Cu, Fe, Mn, and Zn) concentrations in 53 soil samples. Heavy metal concentration ranges as follows: 0.34-2.25 mg/kg Cu, 32-727 mg/kg Fe, 2-750 mg/kg Mn, and 1.31-879.1 mg/kg Zn. Of the measured heavy metals, only Zn concentrations exceeded permissible limits, possibly due to the presence of mining sludge or tailings and slag. Spatially weighted multivariate regression models developed for all heavy metals using soil physicochemical properties produced improved results over OLS regression models. For Fe, the spatial error model retained bulk density only (R2=0.67), for Mn the spatial lag model retained moisture content and TEC (R2=0.60), for Cu, the spatial error model retained moisture content, bulk density, TEC, and percent silt (R2=0.51), and for Zn, the spatial lag model retained pH and TEC (R2=0.71). In general, strong positive correlation is expected between the metals and TOC and clay fractions. This was not evident in the present study. This analysis of soil properties will help define heavy metal concentration and transport in Bumpass Cove, TN.