Date of Graduation

Fall 2016

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology, and Planning

Committee Chair

Robert T. Pavlowsky

Abstract

Historical mining for lead (Pb) in the Old Lead Belt District introduced large volumes of tailings into nearby streams resulting in the large-scale contamination of channel bed and bar deposits in Big River which drains the southeastern Missouri Ozarks. Tailings pile sites have been remediated so that present contamination sources to the river are primarily from the remobilization of Pb stored in channel and floodplain deposits. This study examined the channel geomorphology and sediment geochemistry of Flat River Creek (FRC), a major tributary to the Big River which drains an area that includes three of the six major mines in the District. The goal was to determine the volume of contaminated sediment stored within the channel in bed, active bar, and stable bar deposits assuming the associated stored Pb could be a source of future contamination. Channel sediment contamination >1,000 ppm Pb occurs in the lower 9.5 km of FRC with concentrations spiking below mine locations and decreasing in reaches where tributaries from non-mining areas enter and dilute the mining sediment. Zn concentrations are elevated immediately downstream from the Elvins mine and decrease downstream. Approximately 170,000 m³ of contaminated channel deposits are stored in FRC with 42 % in the lower segment below the most downstream tailings pile. About 24 % of contaminated sediment is stored in channel bed deposits, 41 % in active bar deposits, and 35 % in stable bar deposits. Overall, 133 Mg of Pb and 93 Mg of Zn from mining sources are stored in FRC. Therefore, reworked channel deposits will provide a long-term source of metal contamination Big River as well as FRC.

Keywords

lead, mining, contamination, sediment, Missouri

Subject Categories

Sedimentology

Copyright

© Ralph Joseph Hill

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Sedimentology Commons

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