PBDEs in sediments of the Beijiang River, China: levels, distribution, and influence of total organic carbon.

Forty surface and twenty-two deeper sediment samples were collected from the Beijiang River and analyzed to acquire information about the levels, distribution, possible sources and influencing factors of polybrominated diphenyl ethers (PBDEs) in the Beijiang River. Our results showed that the most abundant BDE congeners in surface sediments were BDE47, 99 and 209, with a median value of 0.044, 0.03, and 5.22 ng g(-1), respectively. The levels of BDE209 in our samples were much higher relative to those of the other BDE congeners and made up more than 90% of the PBDEs levels in almost all samples. Disregarding BDE209, of the remaining 9 BDE congeners the most abundant ones were BDE47 and 99, which contributed 35.7% and 24.6%, respectively, to the median of the 9 congeners. The contribution of the Beijiang River to the PBDE pollution burden of the Pearl River Delta (PRD) was small in comparison to that of the Dongjiang River and the Guangzhou section of the Zhujiang River. PBDEs in the Beijiang River mainly came from use of deca-BDE and penta-BDE with a minor contribution of octa-BDE. The poor correlation between PBDE and TOC may indicate that PBDEs concentrations in the sediments of the Beijiang River were controlled not only by TOC contents, but also by a combined effect of transport, mixing, depositional mechanisms associated with PBDEs, uncontaminated sediments, or fresh input of PBDEs.