Multi-residues of organic pollutants in surface sediments from littoral areas of the Yellow Sea, China

Concentrations of all studied organic pollutants, except for DDTs, were greatest at sites in Dalian Bay, where surface sediment concentrations of PHCs, PAHs, PCBs and DDTs exceeded the corresponding ERL values. The sum concentration of DDTs was greatest in Haizhou Bay exceeding the related ERM value. In terms of compositions of PAHs and PAEs, the predominant components were the MMW and HMW compounds, DBP and DEHP, respectively. The main degradation product of p,p′-DDT was p,p′-DDD at most sampling sites. The principal sources of PAHs and DDTs involved various pyrolytic processes (i.e., combustion of biomass and vehicle exhaust), and application of technical DDT (in the form of impurity or raw material), and a mixture of technical DDT and technical dicofol. Moreover, the coastal site with greatest potential ecological risk from total PAHs was located in Dalian Bay, while the littoral areas of Dalian Bay, two harbor cities (Yantai-Weihai), Jiaozhou Bay, and Haizhou Bay, had relatively high potential risk from DDTs, especially in Haizhou Bay.