Anaerobic Degradation of Decabromodiphenyl Ether

Abstract

The environmental safety of decabromodiphenyl ether (BDE-209), a widely used flame retardant, has been the topic of controversial discussions during the past several years. Degradation of BDE-209 into lower brominated diphenyl ether congeners, exhibiting a higher bioaccumulation potential, has been a critical issue. Here, we report on the degradation of BDE-209 and the formation of octa- and nonabromodiphenyl ether congeners under anaerobic conditions. Sewage sludge collected from a mesophilic digester was used as the inoculum and incubated up to 238 days with and without a set of five primers. Following Soxhlet extraction and a liquid chromatography cleanup procedure, parent compounds and debromination products were analyzed by GC/HRMS. In experiments with primers, concentrations of BDE-209 decreased by 30% within 238 days. This corresponds to a pseudo-first-order degradation rate constant of 1 x 10(-3) d(-1). Without primers, the degradation rate constant was 50% lower. Formation of two nonabromodiphenyl ether and six octabromodiphenyl ether congeners proved that BDE-209 underwent reductive debromination in these experiments. Debromination occurred at the para and the meta positions, whereas debromination at the ortho position was not statistically significant. All three nonabromodiphenyl ether congeners (BDE-206, BDE-207, and BDE-208) were found to undergo reductive debromination as well. No significant change of the BDE-209 concentration and no formation of lower brominated congeners was observed in sterile control experiments. To our knowledge, this is the first report demonstrating microbially mediated reductive debromination of BDE-209 under anaerobic conditions.

Levels and distributions of PBDEs and PCBs in sediments of the Bohai Sea, North China

“…[32][33][34] In this study, the BDE 209 concentration was two orders of magnitude higher than other congeners. Thus the contribution of lower brominated congeners from BDE 209 degradation may not be negligible.…”

Polybrominated diphenyl ethers in surface soils from e‐waste recycling areas and industrial areas in South China: Concentration levels, congener profile, and inventory

“…Previous studies have reported on the photodegradation of BDE-209 to less brominated PBDE congeners in various solid matrices such as sediment, sand, and soil [34,35]. Microbial reductive debromination of BDE-209 and octa-BDEs mixtures under pure culture conditions has also been reported [36,37]. Furthermore, a recent study showed that BDE-209 may be degraded by microorganisms in anaerobic sediment to lessbrominated congeners, such as BDE-99, -47, and -66, and that BDE-99/-47 can also be transformed to BDE-28, BDE-17 by reductive debromination [38].…”

Characterization of polybrominated diphenyl ethers (PBDEs) and hydroxylated and methoxylated PBDEs in soils and plants from an e-waste area, China

“…Lower brominated PBDEs which are not included in the commercial mixtures have been widely detected in the environmental matrices Gerecke et al, 2005;La Guardia et al, 2007;Stapleton et al, 2004;Van den Steen et al, 2007). OH-PBDEs and MeO-PBDEs have been found in marine organisms (algae, mussel and fish), human blood, plants and abiotic samples such as surface water, snow, rain, soils and marine sediments (Bradley et al, 2011;Malmvärn et al, 2005;Sinkkonen et al, 2004;Sun et al, 2013a;Ueno et al, 2008;Verreault et al, 2005;Zhang et al, 2012).…”