Occurrence, profiles, and ecological risks of polybrominated diphenyl ethers (PBDEs) in river sediments of Shanghai, China.

Fifty-two PBDE congeners in river sediments from Shanghai were analyzed in the present study. The concentrations of Σ51PBDEs (defined as the sum of 51 BDE congeners except BDE209) and BDE209 ranged from 0.231 to 119 ng g(-1) and from nd to 189 ng g(-1), respectively. The most abundant BDE congeners in surface sediments were BDE118, 207, 208, 99, 49, 75, 47, 71 and 209, with median values of 1.67, 1.81, 1.83, 1.87, 1.98, 2.52, 2.73, 4.62 and 45.7 ng g(-1) dw, respectively. The concentrations of Σ52PBDEs were significantly correlated with total organic carbon (TOC) content in sediments (p < 0.05). Weak correlations between all PBDE homologues and TOC (r < 0.32) suggest that TOC had a little influence on sediment PBDE transport and distribution patterns in river sediments of Shanghai. Correspondence analysis (CA) showed that PBDEs in sediments in the studied area originated from commercial BDE formulations, combustion emission sources, and debromination of highly brominated PBDEs by aerobic/anaerobic microbes or sunlight. Risk assessment based on risk quotients (RQ) showed that PBDEs in all river sediments collected from Shanghai posed a high potential ecological risk (RQ > 1) to the sediment dwelling organisms, and pentaBDE, decaBDE and tetraBDE were the major ecological risk drivers.