Date of Graduation

Summer 2018

Degree

Master of Science in Geospatial Sciences

Department

Geography, Geology, and Planning

Committee Chair

Robert Pavlowsky

Abstract

Alluvial sediments within the Galena River Watershed were severely contaminated with heavy metals by historical zinc (Zn) and lead (Pb) mining operations during the early 1800s until 1979. Since the mines closed, there have been efforts to remediate on-site mine waste. However, the effectiveness of these efforts to reduce metal concentrations in stream sediments is unknown. This study compares present-day (2017) contamination trends in the Galena River Watershed to trends reported 25 years ago. A total of 415 sediment/soil samples were collected and analyzed using X-ray florescence spectrometry to determine sediment metal concentrations. The highest concentrations of zinc measured were 23,577 ppm in the channel bed, 19,825 ppm in the channel banks, and 51,273 ppm in tailings. Zinc concentrations averaged 198 ppm within the unmined Madden Branch (n=10), 2,057 ppm within the main branch of the Galena (n=31), 9,569 ppm within the heavily mined Diggings Branch (n=11), and 26,158 ppm in tailings (n=16). Present day contamination trends show little difference compared to 25 years ago. However, stream sediments collected downstream of some large-scale remediation projects have shown significant decreases in Zn concentrations. Nevertheless, even with continued efforts to remediate contaminated sediments in the Galena River, high concentrations will probably persist far into the future.

Keywords

sediment contamination, lead, zinc, mining, remediation, Galena River

Subject Categories

Geochemistry | Geomorphology | Hydrology | Water Resource Management

Copyright

© Dylan Alexander King

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