Continuous exposure of chemicals could cause various environmental impacts. Decabromodiphenyl ether (BDE209) and lead (Pb) can co-exist and are discharged simultaneously at e-waste recycling sites (EWRSs). Extensive concerns have been attracted by their toxic effects on soil microorganisms. Thus, by using high-throughput sequencing, this study explored bacterial community responses in a soil system after repeated Pb exposure in the presence of BDE209 in the laboratory during 90-day indoor incubation period. Gene sequencing of 16S rDNA performed on an Illumina MiSeq platform proved that one-off Pb exposure caused higher microbial abundance and community diversity. Additionally, both repetitive Pb treatment and exogenous BDE209 input could change bacterial community composition. Twenty-three different bacterial phyla were detected in the soil samples, while more than 90% of the sequences in each treatment belonged to a narrow variety. The sequence analyses elucidated that Proteobacteria, Acidobacteria, and Bacteroidetes were the top three dominant phyla. Our observations could provide a few insights into the ecological risks of Pb and BDE209 co-existed contamination in soils at EWRSs.
Keywords: BDE209; Bacterial community; Pb; Repeated exposure; Soil microorganism.