Persistence and bioaccumulation potential of alternative brominated flame retardants

Various alternative brominated flame retardants (BFRs) are currently being used as a replacement for polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). In this chapter, recent studies on the evaluation of persistence, long-range transport potential (LRTP) and bioaccumulation potential of alternative BFRs are reviewed focusing on their physicochemical properties and model evaluations, recent field monitoring studies reporting BFR concentrations in remote regions, biomonitoring studies, and mechanistic laboratory studies to assess bioaccumulation. Several alternative BFRs have physicochemical properties similar to those of persistent organic pollutants and model simulations showed that they are likely to be persistent and to travel long-range. A few field monitoring studies also reported finding them in the Arctic regions and oceans, where there are no emission sources of alternative BFRs. Bioaccumulation potential of alternative BFRs has been evaluated using their partition coefficients and biotransformation rate constants obtained in laboratory studies. Biomonitoring studies partly agree with those assessments, although they are not sufficient to conclude that alternative BFRs are highly bioaccumulative. Thus, the evaluation of LRTP and bioaccumulation potential based on prediction models with experimentally determined key parameters is essential especially for newly developed chemicals and for alternatives to regulated chemicals.