Persistent halogenated compounds in waterbirds from an e-waste recycling region in South China

Persistent halogenated compounds (PHCs), such as dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenylethane (DBDPE), and polybrominated biphenyl 153 (PBB 153), were quantified in muscles of five waterbird species collected from an extensive e-waste recycling region in the Pearl River Delta, South China. PCBs, at concentrations up to 1,400,000 ng/g lipid, were the dominant contaminants contributing to 80%-90% of PHCs. PBDEs and organochlorine pesticides (sum of DDTs and HCHs) contributed approximately equally to total PHCs with median concentrations ranging from 37-2200 and 530-4300 ng/g lipid, respectively. This contaminant distribution pattern was different from those acquired by most studies conducted in other regions. The concentrations of PCBs and PBDEs in Chinese-pond heron from the present study were higher than those from most other previous studies with birds having similar trophic levels. The extensive e-waste recycling activities were probably the cause of the elevated PCB and PBDE levels in the bird samples. The median concentrations of PBB 153 and DBDPE ranged from 3-140 and 10-176 ng/g lipid, respectively. The frequent detection and high concentrations of DBDPE in piscivorous birds implicate a potential environmental concern for this "new" brominated flame retardant. Additionally, the interspecies differences in the levels of contaminants and species-specific PBDE congener patterns were also elucidated in the present study.