Quantifying microbial degradation of polybrominated diphenyl ethers by compound-specific isotope analysis

Brominated diphenyl ethers (BDEs) are used at large quantities as flame retardants, e.g. in electronics, plastics and textiles. The BDEs are persistent organic pollutants (POPs) with propensity for long-range transport and, in most cases, bioaccumulation. The levels of BDEs in the environment, as well as in most ecosystems, are significant and increasing exponentially with doubling times of 5-10 years. The ecotoxic potential of BDEs is believed to be analogous to that of the infamous chlorinated POPs, e.g. polychlorinated biphenyls and polychlorinated dibenzo-dioxins. There is a growing body of evidence of BDEs and their hydroxylated metabolites acting as endocrine disruptors. The proposed project aims at the further development of a new tool to study the extent of BDE degradation (and the degradation rate as the next logical step) in the environment. BDEs can be microbially degraded to less brominated congeners in the environment. Novel techniques of compound-specific isotope analysis (CSIA) will be used to quantify the isotope fractionation concomitant to in-vitro microbial degradation. This "calibration" of the CSIA tool is a first step towards the implementation of this technique for BDE fate studies in environmental settings. It represents a significant contribution to the current degradation-monitoring methodologies, and is believed to improve the accuracy and time/cost efficiency of such studies.