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Polybrominated diphenyl ethers (PBDEs), commonly used as a flame retardants for industrial and commercial products, have a strong tendency to accumulate in the interface of water/soil/sediments and are difficult to biodegrade. An effective biological treatment for PBDE removal is needed. In this study, we investigated the use of 3 organic compost materials (BM-2, BM-6, and BP-2) to remove 20 mg kg −1 decabromodiphenyl ether (BDE-209) from contaminated sediment in anaerobic microcosms for 120 days and detected the bacterial community in samples. Organic substance of compost had sorption and biodegradation ability. BM-6 showed the highest sorption of BDE-209, at 38.95%, and BM-3 the highest biological activity, at 34.90%. Methylophilus spp., Pseudomonas spp., Clostridium spp., and Dehalococcoides sp. were identified in anaerobic microcosms with PBDE biodegradation. The pathway of anaerobic DBDE biodegradation from higher to lower brominated PBDE was identified by the appearance of PBDE biometabolites and functional genes related to reductive debromination. We have identified an effective approach for bioremediating PBDE-contaminated sediment by using organic compost; this approach is highly recommended for practical engineering for off-site remediation. [ABSTRACT FROM AUTHOR]

Abstract: Decabromodiphenyl ether (DBDE) is a brominated flame retardant that is commonly used in many commercial products. Sorption of DBDE within a soil/water system can result in serious bioaccumulation within the ecological system and be a threat to human health. Little is known about aerobic DBDE biodegradation, and the influence of the UV light radiation on DBDE biodegradation has not been considered. This study, for the first time, isolates DBDE biodegrading aerobic mixed bacterial cultures from DBDE-contaminated soil/water systems in Taiwan. The aerobic biodegradation of DBDE as a sole carbon source in the presence of 365 nm UVA irradiation over 10 months was investigated using a clay/water system. The rate constants for DBDE degradation gave values ranging from 0.0121 to 0.0134 day−1 in the presence of UV irradiation, which were significantly higher than the 0.0092–0.0102 day−1 values obtained in complete darkness. The aerobic metabolites: 2′,3′-dihydroxy-4-bromodiphenyl ether and 2′,3′-dihydroxy-diphenyl ether were identified by GC–MS. Debromination was ascribed to UV irradiation and biodegradation by facultative aerobic bacteria in the micro-anaerobic environment of the clay/water system. The products of debromination included 12 PBDE congeners (tri- to hexa-BDEs) and their concentrations ranged from 34.28 to 83.80 mg l−1. Specific bacteria capable of degrading PBDEs and carrying out nitrification/denitrification were identified. The present findings suggest that systems using a novel combination of photolysis and biodegradation could be developed to carry out DBDE remediation in the future. [Copyright &y& Elsevier]