Development and Application of a Soil Extraction Method for Perfluoroalkyl Acids

Perfluoroalkyl Acids (PFAAs) have unique properties such as high chemical stability, non-flammability, and water- and oil-repellancy. They are used in many common commercial products; however, due to their unique characteristics they are persistent, bioaccumulative and toxic. Areas close to Union College, such as Bennington, VT, have experienced contamination in their drinking water due to an old chemical plant that resided in the area. There is an approved EPA method for water analysis, but no such method exists for soil samples. Work in this project is focused on developing a soil method to assess the extent of PFAA contamination in the area and how the concentrations vary spatially and temporally. The PFAAs are extracted with basic methanol through an extensive process and then analyzed using liquid chromatography-tandem mass spectrometry. After developing the method to make it more accurate, preliminary results have shown some spatial variation: the further from the old chemical plant, the lesser the contamination. Extraction efficiencies are currently in the 90-100% range, but the method will continue to be optimized in order to obtain as consistent data as possible.