Abstract-Perfluorooctane sulfonic acid (PFOS) accumulates in the liver and blood of exposed organisms. The potential for these surfactant molecules to interfere with hormone/protein interactions in blood is of concern given the importance of these interactions. The PFOS binding to serum proteins was investigated by assessing its ability to displace a variety of steroid hormones from specific binding proteins in the serum of birds and fishes. Perfluorooctane sulfonic acid had only a weak ability to displace estrogen or testosterone from carp serum steroid binding proteins. Displacement of cortisone in avian sera occurred at relatively low PFOS concentrations. Corticosterone displacement potency increased with chain length, and sulfonic acids were more potent than carboxylic acids. The PFOS concentrations estimated to cause these effects were 320 M or greater, equivalent to serum concentrations greater than 160 mg/L. Using mass spectrometry and direct in vitro binding assays, PFOS was demonstrated to bind strongly to bovine serum albumin (BSA) in a 1:1 stoichiometric ratio. It appears that PFOS in serum is in general bound to albumins. Concentrations of PFOS required to saturate albumin would be in excess of 50 to 100 mg/L. Based on current environmental concentrations, it is unlikely that PFOS would cause displacement of hormones from serum proteins in wildlife.

Perfluorooctane sulfonate (PFOS) is a perfluorinated molecule that has recently been identified in the sera of nonindustrially exposed humans. In this study, 247 tissue samples from 15 species of marine mammals collected from Florida, California, and Alaskan coastal waters; and northern Baltic Sea; the Arctic (Spitsbergen); and Sable Island in Canada were analyzed for PFOS. PFOS was detected in liver and blood of marine mammals from most locations including those from Arctic waters. The greatest concentrations of PFOS found in liver and blood were 1520 ng/g wet wt in a bottlenose dolphin from Sarasota Bay, FL, and 475 ng/mL in a ringed seal from the northern Baltic Sea (Bothnian Sea), respectively. No age-dependent increase in PFOS concentrations in marine mammals was observed in the samples analyzed. The occurrence of PFOS in marine mammals from the Arctic waters suggests widespread global distribution of PFOS including remote locations.

No abstract

Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants. The structurally related hydroxylated PBDEs (OH-PBDEs) and methoxylated PBDEs (MeO-PBDEs) occur in precipitation, surface water, wildlife, and humans. The formation of OH-PBDEs in wildlife and humans is of considerable concern due to their greater toxicities relative to PBDEs and MeO-PBDEs. Research to date suggests that OH-PBDEs are formed by hydroxylation of PBDEs, and MeO-PBDEs are then formed by methylation of the OH-PBDEs. Here we show significant metabolic production of OH-PBDEs from MeO-PBDEs while hydroxylation of synthetic PBDEs to OH-PBDEs was negligible. Concentrations of PBDEs, OH-PBDEs, and MeO-PBDEs were analyzed in tuna, albatross, and polar bears collected from marine environments worldwide, and we found a closer relationship between OH-PBDEs and MeO-PBDEs than had been previously reported. Furthermore, for the first time the metabolic relationships between PBDEs, OH-PBDEs, and MeO-PBDEs were elucidated in vitro using rainbow trout, chicken, and rat microsomes. We propose the production of OH-PBDEs from naturally occurring MeO-PBDEs as a previously unidentified mechanism that could be an important contributor for the occurrence of OH-PBDEs found in wildlife from remote areas. Our results suggest that risk assessment paradigms for PBDEs and their metabolites need reevaluation and that human exposure to MeO-PBDEs that occur naturally in marine organisms should be considered.