Chronic Effects of Waterborne PFOS Exposure on Growth, Development, Reproduction and Hepatotoxicity in Zebrafish

To evaluate the potential effects on growth and reproduction of perfluorinated compounds (PFCs), the zebrafish fry (F0, 14 d post-fertilization, dpf) were chronically exposed to various concentrations of PFOS (0, 10, 50 and 250 μg l–1) until sex mature (70 d) and effects on reproductive capacity and endocrine disrupted potential were assessed. No significant adverse effects on survival were observed in developing zebrafish exposed to PFOS for 70 d under all tested concentrations. Reduction of growth (weight and length) and histological alternations most prominently with lipid droplets accumulation in the liver were only observed in the male fish. Whole body triiodothyronine (T3) levels were not significantly changed in both male and female. Gonadal somatic index (GSI) of the females was significantly reduced in the exposure groups. Despite hepatic vitellogenin (VTG) gene expression was significantly up-regulated, no intersex was found in testes as well as the sex ratio was not changed. After 70 d exposure, remaining fish were placed to clean water for 30 d to assess recovery of hepatotoxicity, but histological alternations in the male fish liver were not reversible. To determine possible developmental effects of PFOS exposure on the F1 generation, a subset of exposed females was paired with unexposed males. The results showed that hatching rates were not affected. However, embryo malformations largely with curved spines were observed in 50 and 250 μg l–1 of PFOS treated groups and resulted in mortality. Taken together, the study suggested that long-term maternal exposure zebrafish to lower concentration of PFOS could impair development in the F1 generation, and the risk assessment of estrogenic endocrine disruption of PFOS in the aquatic environment is likely small.