Temporal trends of polybrominated diphenyl ethers in the sediment cores from different areas in China.

This paper presented the historical data on the temporal trends of polybrominated diphenyl ethers (PBDEs) in the sediment cores collected from the Huaihe River, Yellow River and Chaohu Lake, China. Among the 40 targeted PBDE congeners, only 10, 6, and 9 of them were detected respectively in the samples from the Huaihe River, Yellow River and Chaohu Lake. On average, the total PBDEs concentrations in sediments were highest in Chaohu Lake followed by the Huaihe River and the Yellow River. As compared to other PBDE congeners, BDE-209 had higher concentrations and detection rates. The similar down core variation between PBDEs and total organic carbon (TOC) suggests that TOC is an important factor influencing PBDEs distribution in the sediments. The total PBDEs concentrations showed an increasing trend from bottom to upper sediments before a decreasing trend in the topmost sediments. The rapid urbanization and industrialization of these regions in recent decades may cause the historically increasing concentrations of sedimentary PBDEs, especially BDE-209. The decreasing PBDEs concentrations in topmost sediments was probably related to the strict environmental policies at present.