Magnetic Measurements and Heavy Metal Concentrations at Formosa Mine Superfund Site, Douglas County, OR

Abstract:

Advances in the field of environmental magnetism have led to exciting new applications for this field. Magnetic minerals are ubiquitous in the environment and tend to have an affinity for heavy metals. It has been demonstrated that magnetic properties are often significantly related to concentrations of heavy metals and/or pollution loading index (PLI). As a result, magnetic techniques have been used as proxy for determining hot spots of several types of pollution produced from a diversity of anthropogenic sources.

Magnetic measurements are non-destructive and relatively inexpensive compared to geochemical analyses. The utility of environmental magnetic methods varies widely depending on biological, chemical and physical processes that create and transform soils and sediments. Applications in the direction of mapping heavy metals have been studied and shown to be quite useful in countries such as China and India but to date, little research has been done in the US. As such, there is need to expand the scope of research to a wider range of soil types and land uses, especially within the US.

This study investigates the application of environmental magnetic techniques to mapping of heavy metal concentrations and PLI at the Formosa Mine Superfund Site, an abandoned mine about 25 miles southwest of Roseburg, OR. Using hotspot analysis, correlation and cluster analyses, interactions between metals and magnetic parameters are examined in relation to environmental factors such as proximity to seeps and adits. Preliminary results suggest significant correlation of magnetic susceptibility with certain heavy metals, signifying that magnetic methods may be useful in mapping heavy metal hotspots at this site.