Polyfluorinated chemicals in a spatially and temporally integrated food web in the Western Arctic.

This study reports on an investigation of the presence of polyfluorinated chemicals in a spatially and temporally integrated set of biological samples representing an Arctic food web. Zooplankton, Arctic cod, and seal tissues from the western Canadian Arctic were analyzed for perfluoroalkyl sulfonates [PFAS], perfluorocarboxylates [PFCAs], and other polyfluorinated acids. Perfluorooctane sulfonate [PFOS] was found in all samples [0.20-34 ng/g] and in the highest concentrations. PFCAs from nine to 12 carbons were quantified in most of the samples [0.28-6.9 ng/g]. PFCAs with carbon chain lengths of eight or less were not detected. Likewise, 8-2 fluorotelomer acid [8-2 FTA] and 8-2 fluorotelomer unsaturated acid [8-2 FTUA], products of fluorotelomer environmental transformation, were not detected. 2H,2H,3H,3H, heptadecafluoro decanoic acid [7-3 Acid], an additional metabolite from fluorotelomer biological transformation, was detected only in seal liver tissue [0.5-2.5 ng/g]. The ratios of branched to linear PFOS isomers in fish and seal tissue were not similar and did not match that of technical PFOS as manufactured. No branched PFCA isomers were detected in any samples. It is concluded that differing pharmacokinetics complicate the use of branched to linear ratios of PFCAs in attributing their presence to a specific manufacturing process. A statistical analysis of the data revealed significant correlations between PFOS and the PFCAs detected as well as among the PFCAs themselves. The 7-3 Acid was not correlated with either PFCAs or PFAS, which suggests that it may have a different exposure pathway.

Matrix effect-free analytical methods for determination of perfluorinated carboxylic acids in environmental matrixes.

Perfluorocarboxylic acids (PFCAs) are persistent chemicals that have been found widely in the environment. Their accurate determination in environmental matrixes, particularly soil, sediment, and sludge, at low levels presents significant analytical challenges. The commercialization of electrospray interfaces for liquid chromatography-mass spectrometric analysis facilitated analysis of PFCAs at low levels, but issues with quantitative analysis due to matrix suppression or enhancement still persist. The methods described in this study utilize simple and rapid sample purification procedures to remove matrix components sufficiently so that errors due to coeluting matrix peaks are negligible and recoveries of PFCAs are consistently and reproducibly quantitative. Extracts from solid samples (soil and sediment) and liquid bacterial sludge are purified using dispersive solid-phase extraction. Recovery values generally are in the 70-120% range, with limits of quantitation of 1 ppb. The method utilizes an extraction solvent previously shown to release and recover aged residues of PFCAs. A confirmatory method using two precursor to product ions is also provided and demonstrated.