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.
Bibliographical noteFunding Information:
We are grateful to Fan Yang (Environment Canada) for dating analysis of Lake Ontario, Plastic Lake, and L442 cores, Daniel Engstrom (St. Croix Watershed Research Station, Science Museum of Minnesota) for core collection and dating from Lake Tettegouche, Ron Ingram and Andrew Paterson (Dorset Environmental Science Center, Ontario Ministry of Environment) for core collection from Plastic Lake, Bernard Lalonde and Bruno Rosenburg (Freshwater Institute, Fisheries & Oceans Canada) for core collection from L442, and technical operations staff from Environment Canada and the crew of the CCGS Limnos for core collection from Lake Ontario. The study was supported in part by the Great Lakes Atmospheric Deposition program through the Great Lakes Commission .