To Örebro University

Perfluoroalkyl acids (PFAAs) are persistent organic pollutants that can commonly be found in environmental matrixes and wildlife from all over the globe. The PFAAs have been used in applications such as water and dirt repelling treatments for textiles, oil-resistant paper coatings and fire-fighting foams. Four studies were designed to evaluate the occurrence of PFAAs in Swedish populations of birds, the developmental toxicity of different PFAAs and species sensitivity differences as well as possible modes of action for the toxicity. The studied species were domestic chicken, and the wild species great cormorant and herring gull. Cormorant and gull eggs were collected from bird colonies in Lake Vänern, Sweden. Chemical analyses were performed on some of the eggs to determine the occurrence of 15 PFAAs in the eggs. The other eggs and eggs of domestic chicken were incubated and injected with solutions of the PFAAs PFOS, PFOA, PFBS and PFUnDA. The eggs were candled every 1-3 days to determine viability. High levels of PFAAs, mainly PFOS followed by PFUnDA, were found in the herring gull and great cormorant eggs. PFOS was found at concentrations up to 1163 ng/g and 771 ng/g in cormorant and herring gull, respectively. In the toxicity tests, chicken was found to be more sensitive than the wild species and cormorant was in general the least sensitive species. PFOA was found to be the most toxic of the chemicals followed by PFOS, PFBS and PFUnDA in decreasing order. Comparing these results with the levels of these chemicals found in the eggs of herring gull and great cormorant, PFOS is the chemical of most concern. Although PFOA had the highest toxicity, the levels found in the eggs were very low. In an additional study, the hepatic β-oxidation in developing chicken embryos after in ovo exposure to PFOS was studied with a tritium release assay. PFOS was found to increase the β-oxidation of palmitic acid at PFOS concentrations 3-7 times lower than the average egg levels in cormorant and herring gull. Therefore the occurrence of effects on the fatty acid metabolism cannot be ruled out. The doses of effect on embryo survival in the toxicity and the levels found in the herring gulls and cormorants gives a small margin of safety for the wild populations. Continued environmental monitoring and further studies on the toxicity of PFAAs that occur at high environmental concentrations is important.