Concentrations, distribution and sources of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls in coastal sediments from Xiamen, China

•Levels of PCDD/Fs and DL-PCBs were investigated to evaluate organic contaminations due to high-speed economic development in southeastern coastal China.•TEQ values in most samples were higher than the guideline, which means their toxicity and ecological effects cannot be ignored in densely populated estuarine environments.•PCDD/Fs may have originated from usage of pesticides and from atmospheric deposition during the shift period from agriculture to industry.

Xiamen and its surroundings are representative areas suffering from intense anthropogenic turbulence and contamination in southeast coast of China during rapid industrialization and urbanization period, thus relevant organic pollutants research is necessary to assess the coastal environmental quality and generate management strategy. Contamination status of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) was investigated for 7 surface sediment samples collected in these areas in January 2007. The given data were used to evaluate the contamination and their potential risks of the pollutants. Concentrations of PCDD/Fs were in the range of 60 to 4089 pg g− 1 (dry weight) with an average of 1706 pg g− 1 and DL-PCBs in the range of 3 to 76 pg g− 1 with an average of 28 pg g− 1. Octa-chlorinated dibenzo-p-dioxin (OCDD) and PCBs 105 and 118 were the main congeners of the PCDD/F and DL-PCB, respectively. The toxicity equivalent concentrations (TEQs) were in the range of 0.15 to 5.2 pg g− 1 (average: 3.0 pg g− 1) for PCDD/Fs, while in the range of < limit of quantitation (LOQ) to 0.09 pg g− 1 (average: 0.05 pg g− 1) for DL-PCBs. Congener pattern analysis showed a dominance of OCDD, suggesting main sources were current or historical use of chlorophenol, current use of dioxin contaminated pesticides or atmospheric deposition. Due to the current levels of PCDD/Fs and DL-PCBs in this area, it is necessary to further research their biogeochemical processes and ecological influences in the future.