Determination of environmentally relevant exposure concentrations of polybrominated diphenyl ethers for in vitro toxicological studies.

Toxicological studies at environmentally relevant concentrations are essential for understanding ecotoxic and health risks of pollutants such as polybrominated diphenyl ethers (PBDEs). However, no information is available on what exposure levels of PBDEs in vitro studies are environmentally relevant. We exposed MCF-7, HepG2, H295R and PC12 cells to BDE-47, and measured BDE-47 concentrations in the cells after exposure. We also used the percentile method to summarize literature data on environmental exposure levels of biotic tissues to PBDEs. The exposure concentration that resulted in a BDE-47 burden in cells close to the 90th percentile of PBDEs levels in tissues was assigned as the upper limit for the environmentally relevant concentration. Exposure to 1nM BDE-47 resulted in PBDEs burdens in MCF-7, HepG2 and H295R cells close to the 90th percentile but PBDEs burdens in PC12 cells were higher than the 90th percentile. In consideration of the high exposure levels in PBDE-polluted areas, we concluded that the highest environmentally relevant exposure concentration of PBDEs in culture media should be approximately 10nM for MCF-7, HepG2 and H295R cells, and<10nM for PC12 cells. These results provide an approximate reference for setting environmentally relevant exposure concentrations of PBDEs for studies in vitro.