Presenter(s): Rachael Cleveland – Environmental Science
Faculty Mentor(s): Matthew Polizzotto
Poster 66
Research Area: Natural/Physical Science
Funding: UROP mini-grant
The history of mining in Oregon has left a legacy of contaminated and abandoned sites that threatens environmental and human health. The goal of this research is to better understand mercury (Hg) cycling within an Oregon watershed that is being contaminated by an abandoned mine. The chosen site is the Superfund site at Black Butte Mine, where contaminated sediment has washed down a series of streams that drain into Cottage Grove Reservoir. The specific objectives of this work are to determine how Hg sediment concentrations, forms, and reactivity change from the mine site to the reservoir and how these factors change within the different areas of the reservoir. Sediment sampling was conducted at the Black Butte Mine site, along drainage creeks and streams, and throughout the Cottage Grove Reservoir. Sediment composites were collected and used for total Hg and speciation analysis. Based on previous studies about Hg cycling in the environment, the concentrations of mercury are expected to decrease with distance from the mine site until reaching the reservoir, where it will increase due to Hg deposition and accumulation. Mercury in sediment should become progressively more reactive from the mine site to the reservoir. Within the reservoir, reactivity and concentrations of Hg are expected to be higher in the floodplains that experience seasonal variations than the permanently inundated areas. This information, particularly the forms of mercury found, has significant implications for Hg bioaccumulation and the resulting safety of humans and species that live within the watershed.