Spatial and Temporal Distributions of Short-, Medium-, and Long-Chain Chlorinated Paraffins in Sediment Cores from Nine Lakes in China.

The spatial and temporal distributions of short-, medium-, and long-chain chlorinated paraffins (SCCPs, MCCPs, and LCCPs) were studied in sediment cores and surface sediment from nine lakes in China. The highest total CP concentrations in surface sediment were found in the plateau lakes of southwest China, followed by lakes in the northeast, east, and remote northwest. The concentrations of three CP groups in cores showed an increasing trend from the 1970s to 2014, with the most rapid increase occurring from the late 2000s to 2014, consistent with the statistics on historical production of CPs in China. The three CP groups showed site-specific profiles in sediments from the nine lakes, and their percentages changed with sedimentary years. In sediment samples with dated year after 1980, MCCPs were dominant in sediment from Lakes Sihailongwan maar, Taihu, Erhai, and Chenghai, and LCCPs were predominant compounds in the other five lakes. The proportions of LCCPs rapidly increased after 1980, reflecting the increasing production and usage of LCCPs in China. The total burdens of ∑SCCPs, ∑MCCPs, and ∑LCCPs in sediment prior to 2006 were estimated to be 0.26-5100, 0.29-21000, and 0.07-4300 kg, respectively, which were 1.4-440-fold higher than those of ∑PBDEs.