Perfluorooctanesulfonate and periluorooctanoate in red panda and giant panda from China

High accumulation of perfluorooctane sulfonate (PFOS) in marine tucuxi dolphins (Sotalia guianensis) from the Brazilian coast

Perfluorooctane sulfonate (PFOS) and other perfluoroalkyl compounds (PFCs) were measured in liver samples from 29 marine tucuxi dolphins from Rio de Janeiro state (RJ), Brazil. PFC measurement combined liquid chromatography and mass spectrometry, using a CapLC system connected to a Quadrupole-LIT mass spectrometer. PFOS was the only PFC detected and it was so in all samples. PFOS concentrations (ng x g(-1) dw) of dolphins (n=23) from the highly contaminated Guanabara Bay (in RJ) varied between 43 and 2431 as well as between 76 and 427 from areas of RJ other than the quoted bay (n=6). Concentrations of three fetuses and one neonate varied between 664 and 1590. Fetus/mother ratios were calculated in two situations (2.75 and 2.62). It seems that mother-to-calf transference plays important role for relationships between PFOS and age. When a one-year-old male calf presenting 2431 ng x g(-1) dw was excluded from the test, significant correlations were observed between PFOS concentrations and both age and total length. Despite the placental transference, PFOS concentrations were not significantly lower in females than in males. PFOS levels in marine tucuxi dolphins from Guanabara Bay are among the highest detected to date in cetaceans, and this may represent a threat to the small population concerned.

Molecular characterization of cytochrome P450 1A and 3A and the effects of perfluorooctanoic acid on their mRNA levels in rare minnow (Gobiocypris rarus) gills

Perfluorooctanoic acid (PFOA), a potentially toxic perfluorinated compound (PFC), has been widely disseminated in the environment. In the present study, rare minnows (Gobiocypris rarus) exposed to PFOA exhibited histopathological gill damage, including epithelial hyperplasia of the lamellae, inflammatory cell infiltration, and lamellar fusion. Cytochrome P450s (CYPs) play a central role in the metabolism and biotransformation of a wide range of endogenous substrates and foreign compounds. Thus, we studied the CYPs and the effects of waterborne PFOA on their corresponding mRNA levels in the gills of rare minnows. Two novel CYP cDNAs (CYP1A and CYP3A) were identified in rare minnow and their mRNAs were ubiquitously expressed in all tissues examined. Upregulation of CYP3A mRNA was observed in the gills of male rare minnows exposed to 30mg/L PFOA, while no significant changes occurred in exposed females. In contrast, down regulation of CYP1A mRNA was detected in the gills of male and female minnows exposed to PFOA. However, the effect of PFOA on gill mRNA levels of their potential regulators, aryl hydrocarbon receptor (AhR) for CYP1A, and pregnane X receptor (PXR) for CYP3A, were not consistent with the observed effects of PFOA on the corresponding CYP mRNA concentrations. This suggests a different or more complex transcriptional regulation of CYP expression following PFOA exposure.

Evaluation of estrogenic activities and mechanism of action of perfluorinated chemicals determined by vitellogenin induction in primary cultured tilapia hepatocytes

Perfluorochemicals (PFCs) are emerging persistent organic pollutants (POPs) and are widely present in the environment, wildlife and humans. Recently, reports have suggested that PFCs may have endocrine-disrupting activities. In the present study, we have developed a non-competitive enzyme-linked immunosorbent assay (ELISA) method to investigate estrogenic activities of selected PFCs using vitellogenin (VTG) induction in primary cultured hepatocytes of freshwater male tilapia (Oreochromis niloticus). Cultured hepatocytes were exposed to various concentrations of perfluorooctanyl sulfonate (PFOS), pentadecafluorooctanoic acid (PFOA), 1H, 1H, 2H, 2H-nonafluoro-1-hexanol (4:2 FTOH), 1H, 1H, 2H, 2H-perfluorooctanol (6:2 FTOH) and 1H, 1H, 2H, 2H-perfluoro-1-decanol (8:2 FTOH) for 48 h, while 17beta-estradiol (E2) and 4-nonylphenol (4-NP) were used as positive controls. A dose-dependent induction of VTG was observed in E2-, 4-NP-, PFOS-, PFOA- and 6:2 FTOH-treated cells, whereas VTG levels remained unchanged in the 4:2 FTOH and 8:2 FTOH exposure groups at the concentrations tested. The estimated 48-h EC(50) values for E2, 4-NP, PFOS, PFOA and 6:2 FTOH were 4.7 x 10(-7), 7.1 x 10(-6), 1.5 x 10(-5), 2.9 x 10(-5) and 2.8 x 10(-5)M, respectively. In the time-course study, significant VTG induction took place at 24 h (E2), 6 h (4-NP), 48 h (PFOS), 48 h (PFOA), 72 h (4:2 FTOH), 12 h (6:2 FTOH), 72 h (8:2 FTOH), and increased further after 96 h of exposure. Co-exposure to binary mixtures of individual PFCs and E2 for 48 h significantly inhibited E2-induced hepatocellular VTG production in a dose-dependent manner except for 4:2 FTOH. The estimated 48-h IC(50) (concentration of a compound that elicits 50% inhibition of maximally E2-induced VTG) values for PFOS, PFOA, 6:2 FTOH and 8:2 FTOH were 3.1 x 10(-7), 5.1 x 10(-7), 1.1 x 10(-6) and 7.5 x 10(-7)M, respectively. In order to further investigate the estrogenic mechanism of PFCs, the hepatocytes were co-exposed to binary mixtures of individual chemicals (E2, 4-NP, PFOS, PFOA and 6:2 FTOH) and the known estrogen receptor inhibitor tamoxifen for 48 h; tamoxifen significantly inhibited the ability of these chemicals to stimulate vitellogenesis. The overall results demonstrated that PFOS, PFOA and FTOHs have estrogenic activities and that exposure to a combination of E2 and PFCs produced anti-estrogenic effects. The results of the estrogen receptor inhibition assay further suggested that the estrogenic effect of PFCs may be mediated by the estrogen receptor pathway in primary cultured tilapia hepatocytes.

Historical trends in human serum levels of perfluorooctanoate and perfluorooctane sulfonate in Shenyang, China

Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are widespread contaminants in the environment, as well as in wildlife and in humans. The PFOS and PFOA concentrations were determined in historical human serum samples collected in Shenyang, China, in 1987 (n=15), 1990 (n=33), 1999 (n=68) and 2002 (n=119). The serum donors were students, faculty members and university workers. Since the serum PFOA and PFOS levels did not follow a normal or log-normal distribution, a nonparametric method was applied to analyze the historical trends. For the total male and female subjects, the median level of serum PFOA increased significantly from 0.08 microg/l in 1987 to 4.3 microg/l in 2002 (p<0.05), while the median level of serum PFOS also increased significantly from 0.03 microg/l in 1987 to 22.4 microg/l in 2002 (p<0.05). Both the serum PFOA and PFOS levels continued to increase from 1999 to 2002, with remarkable increases observed in females: 6.3-fold increase for PFOA and 13-fold increase for PFOS. In 2002, serum PFOA and PFOS concentrations of female subjects have increased to 4.9 microg/l and 22.4 microg/l in median, respectively, which are comparable to those in U.S.A. and Japan. For male subjects, serum PFOA and PFOS concentrations (1.6 microg/l and 8.3 microg/l in median, respectively) are comparable to those in Italy. The data from this study indicate that females are likely to experience higher exposure to these chemicals.