Transport of Perfluorochemicals to Surface and Subsurface Soils

Minnesota Department of Transportatio

Transport of Perfluorochemicals to Surface and Subsurface Soils

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), as persistent organic pollutants, are ubiquitously present in the environment, and have been detected in human blood and breast milk at concentrations of concern to health and environmental regulators. This project aims 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 of our surface soils samples (0.2–125.7 ng/g dry soil weight). The results of the surveying and sampling program and subsequently geo-statistical modeling with the aid of a Geographic Information System (GIS) identified two hot spots, and supported wind as the primary transport carrier 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 from contaminated spots. We also studied their 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.Minnesota Department of Transportation (MnDOT

Application of a comprehensive extraction technique for the determination of poly- and perfluoroalkyl substances (PFASs) in Great Lakes Region sediments.

A comprehensive method to extract perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acids (PFCAs), polyfluoroalkyl phosphoric acid diesters (diPAPs), perfluoroalkyl phosphinic acids (PFPiAs) and perfluoroalkyl phosphonic acids (PFPAs) from sediment and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to sediment cores from three small isolated lakes (Plastic Lake, Lake 442, Lake Tettegouche) and Lake Ontario in the Great Lakes Region. Recoveries of the target compounds using the optimized acetonitrile/sodium hydroxide extraction ranged from 73% to 120%. The greatest concentrations of per- and polyfluorinated alkyl substances (PFASs) were recorded in sediment from Lake Ontario (ΣPFASs 13.1 ng/g), where perfluorooctane sulfonic acid (PFOS) contributed over 80% of the total. Concentrations in Lake Ontario were approximately 1-2 orders of magnitude greater than the more remote lakes subject to primarily atmospheric inputs. Whilst the PFAS contribution in Lake Ontario was dominated by PFOS, the more remote lakes contained sediment with higher proportions of PFCAs. Trace amounts of emerging PFASs (diPAPs and PFPiAs) were found in very recent surface Lake Ontario and remote lake sediments

Enhanced Sorption as a Means to Sequester PFAS

Matt Simcik - Associate Professor, Division of Environmental Health Sciences, University of Minnesota. Dr. Simcik, along with his colleagues, have developed an in situ remediation method for PFAS contaminated groundwater. It involves the addition of cationic polymer coagulants and in some cases powdered activated carbon. They also have plans to develop this method for surface water, wastewater treatment, landfill leachate as well as increasing the efficiency of drinking water treatment. Dr. Simcik presented results of our work on developing the method and plans for field implementation.Ope