[Vertical profile of polybrominated diphenyl ethers (PBDEs) in sediment from an E-waste area in South China]

Polybrominated diphenyl ethers (PBDEs) were determined in a sediment core collected from a reservoir in an electronic waste (e-waste) area of South China. PBDEs were detected throughout the core,with a mean value of 9.26 ng/g dry weight. 0.43 to 141 ng/g PBDEs concentrations were low (0.43-2.30 ng/g) and varied less in the lower layers (below 16 cm) of the core,whereas their concentrations increased remarkably in the upper layers (2.90-141 ng/g). The vertical distribution of PBDEs indicated the influence of local e-waste recycling activities. PBDEs originated from commercial deca-BDE mixture were the dominant congeners, accounting for 79.6% of the total PBDEs, followed by PBDEs from penta-BDEs (14.7%). PBDEs from octa-BDEs contributed only 5.69%. The difference between PBDE congener profiles in the sediment and those in the commercial penta-, octa-, and deca-BDEs suggests the possible degradation of highly brominated PBDEs in the sediment, which was further supported by the occurrence of BDE202 and the vertical variation of the fractions of nona-BDE congeners and ratios of BDE197/BDE201. However, more work is needed regarding PBDE degradation in the environment.