Debromination of decabromodiphenyl ether (BDE-209) and bacterial community responses in aerobic and anaerobic soil microcosms

Abstract

Polybrominated diphenyl ethers (PBDEs) are a class of persistent organic pollutants that may pose risks to human health and environmental biota, including soil microbial communities. These risks are further affected by a multitude of factors, including environmental conditions encountered in real-world settings. A comprehensive understanding of how PBDEs transform and microbial communities respond to the exposure under varying environmental conditions is paramount for assessing the ecological risks or identifying potential degraders. In this study, soil microcosms spiked with or without 10 mg kg⁻¹ decabromodiphenyl ether (BDE-209) were established and incubated under either aerobic or anaerobic conditions for a duration of up to 180 days. The results demonstrated mono- to nine-brominated PBDE congeners accounted for approximately 4.03 % and 6.18 % of the initial concentration of BDE-209 added to the soil in both aerobic and anaerobic conditions, respectively. Anaerobic microcosms demonstrated faster and deeper debromination compared to the aerobic microcosms. Bacterial communities were monitored during the incubation to evaluate the community succession under the PBDE stress. Oxygen significantly shaped the richness, diversity, composition, and network complexity of soil bacterial community. BDE-209 had profound impacts on the network structure of bacterial communities. Random Forest model identified Desulfosporosinus and Polaromonas that might be related to BDE-209 debromination under anaerobic conditions. Overall, our findings shed light on the bacterial community effects of BDE-209 in aerobic or anaerobic soils, thus providing a theoretical basis for remediation of soil contaminated by PBDEs.