Partition and source identification of organophosphate esters in the water and sediment of Taihu Lake, China

Taihu Lake is the third largest freshwater lake in China, and has been heavily polluted by surrounding industrial activities. This study aimed to investigate the sources of organophosphate esters (OPEs) in Taihu Lake, and their partitioning behaviors between sediment and water. The total concentrations of the eleven target OPEs (∑OPEs) in the water and sediment of Taihu Lake were 166-1530 ng/L and 2.82-47.5 ng/g dw, respectively. The ∑OPEs in both water and sediment generally decreased from northwest to southeast. Extremely high level of ∑OPEs (1410-15,300 ng/L) was found in the flow-in rivers passing through the OPE manufacturing regions in Yixing. In both water and sediment, tris(2-chloroisopropyl) phosphate and tris(chloroethyl) phosphate were the predominant OPEs. The sediment-water partitioning coefficients, log K_oc, of OPEs were calculated based on paired sediment and water samples, and they displayed strong correlation with their log K_ow (octanol-water), suggesting that their partition was dominated by hydrophobic interaction. Principle component analysis indicated that OPE manufacturing in Yixing was an important point source of OPEs, especially of TCIPP in Taihu Lake. Many OPE-related industries, such as electronic, textile, machine and plastic industries around Taihu Lake also made contributions to OPEs in the Lake.