Brominated flame retardants (BFRs) in sediment from a typical e-waste dismantling region in Southern China: Occurrence, spatial distribution, composition profiles, and ecological risks

Our study evaluated the current occurrence, composition, and spatial distribution of eight congeners of polybrominated diphenyl ethers (PBDEs) and seven novel brominated flame retardants (NBFRs) in sediment from Guiyu, a typical e-waste dismantling region in China. PBDEs levels ranged from 0.345 to 401,000 ng/g dw and NBFRs levels ranged from 0.581 to 73,100 ng/g dw. Almost all sediment samples contained high levels of BDE-209 and DBDPE, and the ratio of DBDPE/BDE-209 in sediments ranged from 0.0814 to 2.80 (mean: 0.879). The concentration and composition profiles for BFRs in sediments from both mainstream and tributaries of two major rivers in Guiyu reach (and adjacent downstream locations) differed significantly from those far from Guiyu town. Whereas the high presence of BFRs in Guiyu reflected the historical crude e-waste dismantling activities in the region; the locations far from Guiyu town were likely to receive BFRs from atmospheric deposition, not originated from the region, as BFRs in water-sediment are known to be able to migrate a limited distance along the river. Ecological risk assessment revealed that the low brominated congeners of PBDEs and BDE-209 posed an unacceptable risk to the sedimentary life at multiple locations. Our results updated our knowledge of BFRs contamination in Guiyu, suggesting the necessity of continuous source monitoring, control procedures, and sediment cleanup for BFRs.