Source Apportionment of Perfluorochemicals (PFCs) in Highway Runoff: Are Transportation Activities a Major Source of PFCs?

Project summary:

The persistent organic pollutants perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are ubiquitous in the environment and have been detected in human blood and breast milk at concentrations that concern health and environmental regulators. This project aimed to identify the PFOS/PFOA contamination sources, contaminant release mechanisms, and migration pathways from contaminated soils. Soil samples at different depths along and perpendicular to a U.S. highway were collected, and both compounds were regularly quantified in all surface soils samples (0.2-125.7 ng/g dry soil weight). The results of the surveying and sampling program, and subsequently, of geo-statistical modeling with the aid of a Geographic Information System (GIS), identified two hot spots and supported wind as the primary transport causing the mitigation of contaminated soils from the hot spots to off-site soils. The observations indicate that PFOS and PFOA contamination is not contained to a few hot spots, but is migrating with wind and traffic to other locations. This proposed soil-to-soil migration pathway appears to be an important and heretofore overlooked migration mechanism of PFOS and PFOA. The research also studied the PFOS and PFOA occurrence and fate in subsurface soil samples and found a general increase in concentrations with the depth at which soil samples were collected, indicating that the contamination is also migrating toward the groundwater table.