Perfluorinated compounds in the Great Lakes

Abstract

Perfluoroalkyl acids (PFAs) are released to the environment via their manufacturing processes, their use in commercial products, or indirectly via oxidation of precursor molecules containing perfluoroalkyl chains. PFA precursors are diverse and include poly- and perfluorinated alcohols and perfluoroalkyl sulfonamide derivatives. Products in which PFAs and their precursors have been used include wetting agents, lubricants, stain resistant treatments, and fire-fighting foams. The PFAs in the environment comprise two general classes: perfluoroalkyl carboxylates such as CF3(CF2)yCO2- and perfluoroalkyl sulfonates, such as CF3 (CF2)xSO3-. The predominant PFA in biota samples from the Great Lakes is perfluorooctane sulfonate (PFOS), but a homologous series of perfluoroalkyl carboxylates, where x = 6 - 3, is also detected in most samples at lesser concentrations. The environmental behavior of most PFAs is not well studied, and our knowledge of the physicochemical properties of PFOS and PFOA is limited. Both compounds are persistent in the environment and are not expected to volatilize into the atmosphere to a significant extent, but have much greater water solubilities than similar chlorinated compounds. Concentrations of PFOS in surface waters are usually less than those of perfluorooctanoic acid (PFOA), but PFOS accumulates in aquatic organisms to a greater extent and appears to biomagnify in the food web of the Great Lakes region. PFAs and/or their precursors have been measured in air, surface waters, sediments, aquatic invertebrates, and in the tissues of fish, fish-eating water birds, mink, otter, and other wildlife from in and around the Great Lakes. Although the sources of PFAs to the Great Lakes are not well understood, fluorotelomer alcohols (FTOHs) and perfluorooctylsulfonamides degrade to perfluoroalkyl carboxylates and PFOS, respectively, in laboratory studies. Based on preliminary and incomplete information, current concentrations of PFOS in the Great Lakes environment do not seem to be sufficient to pose a significant risk to most aquatic organisms including fish. However, the margins of safety are less for mammals such as mink and birds and when the concentrations of all PFAs are considered together, current concentrations may pose risk to some sensitive species. © Springer-Verlag Berlin Heidelberg 2006.