Document Type

Thesis

Date of Degree Completion

Spring 2018

Degree Name

Master of Science (MS)

Department

Cultural and Environmental Resource Management

Committee Chair

Dr. Karl Lillquist

Second Committee Member

Dr. Carey Gazis

Third Committee Member

Dr. Clay Arango

Abstract

Effluent from abandoned mine lands (AMLs) in several drainages in Washington’s Eastern Cascades flows into the Yakima River. Similar sites in Idaho and Colorado are known producers of heavy metals and acid mine drainage. I determined the effects of nine AMLs on water quality in four tributaries to the Yakima River. Archival work was conducted to determine sites that were mined and contained a mill. Each site was characterized by physical features. Water and sediment samples were collected above, at, and below each AML. Samples were analyzed for pH and heavy metal content, and evaluated to determine if the AMLs are sources of pollution as defined by EPA drinking water standards. Results show that mill sites in the Cle Elum and Teanaway River drainages are contributing small amounts of heavy metals to their surrounding environment. Analysis using modified USGS mine waste characterization techniques also shows that these sites are among the most likely to contribute these pollutants to fluvial systems. Additionally, due to local geologic influences, arsenic and lead in water samples were elevated above EPA standards throughout the study area, and the effects of acid mine drainage make these metals more bioavailable. These AMLs contribute to low discharge systems and the effluents from these sites will disproportionally impact them compared to larger downstream systems; however, it the effect they will have on either is likely limited. These results may be extrapolated to other, similar small-scale, historical mineral processing sites in the region, indicating that they pose less environmental hazard than larger sites.

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