[pp.93-100]
Kiyotaka TSUNEMI (National Institute for Advanced Industrial Science and Technology)
Abstract:
The group of polybrominated diphenyl ethers (PBDEs) is a class of flame retardants widely used in electronics, furniture and textiles. The consumption volume of PBDEs is decreasing in Japan, and in the past ten years decaBDE has been produced and used mainly in products. However, monitoring data suggest that decaBDE with low toxicity may be degraded to lower brominated congeners with high toxicity in the environment and in organisms. The risk of decaBDE posed to human health may therefore be underestimated. In this study, cumulative risk assessment of PBDEs as complex mixture was conducted using the component-based relative potency factor (RPF) approach. First, dietary intake was defined as the main exposure route for adults and the mean level of daily intake of PBDEs was estimated. Then, eight scenarios were adopted with different combination with factors of toxic levels of congeners, endpoints and toxicity index. Finally, the exposure for each congener was normalized and summed using the calculated RPFs. As a result, although the risk of whole PBDE mixture is up to three orders magnitude more than the risk of decaBDE, the risk of whole PBDE mixture is very low in all scenarios, therefore, additional risk reduction measures are not needed in the current levels of PBDE contamination.
Key Word:
polybrominated diphenyl ethers, chemical mixture, relative potency factor, margin of exposure