Xiaoyan Yun

Occurrence, distribution and seasonal variations of polychlorinated biphenyls and polybrominated diphenyl ethers in surface waters of the East Lake, China.

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the surface water of the East Lake, China were investigated in winter (2012) and summer (2013). A hundred and eight samples were collected from 36 sampling sites and analyzed for the 31 PCB and 10 PBDE congeners. Concentrations of both PCBs and PBDEs showed obvious seasonal variations. The average PCB concentrations in the East Lake ranged from 3.17 to 6.09 ng L(-1) in winter and 0.19 to 0.99 ng L(-1) in summer. CB-44, 105, 118 and 179 were dominant in both winter and summer. The average PBDE concentrations in the East Lake ranged from 2.92 to 5.54 ng L(-1) in winter and 0.67 to 1.51 ng L(-1) in summer. BDE-47 was predominant in both winter and summer, which accounted for more than 37% of the total PBDEs concentration from all sampling sites. Independent-Samples t-test showed statistical significance of ΣPCBs and ΣPBDEs between winter and summer samples. The analysis of distribution, pattern and seasonal variations indicated the different potential sources of PCBs and PBDEs in the East Lake. The potential eco-toxicological risk was also discussed in the study.

Occurrence, sources, and cancer risk of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in agricultural soils from the Three Gorges Dam region, China

Eighty agricultural topsoil samples were collected near the Three Gorges Dam region of Yangtze River, China, to investigate concentrations, distribution patterns, and possible sources and potential cancer risks of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in this area. Total PAHs concentrations in agricultural top-soil ranged from 277.79 to 3,217.20 ng g−1 (ppb) with a mean concentration of 1,023.48 ± 815.31 ng g−1. Total concentrations of seven carcinogenic PAHs (C-PAHs) were between 45.85 ng g−1 and 1,147.45 ng g−1, accounting for 6% to 49% of the total PAHs. Total PCBs concentrations varied from 18.56 to 183.90 ng g−1 with a mean concentration of 35.28 ± 41.01 ng g−1. Positive linear correlations were found between total PAHs and total PCBs, showing these compounds may originate from common sources. Isomer ratios analysis indicated that atmospheric deposition was the main common source for PAHs and PCBs. The incremental lifetime cancer risk (ILCR) of PCBs in agricultural topsoil near the Three Gorges Dam region were all below 10−6, indicating no cancer risk, whereas ILCR of PAHs were between 10−6 and 10−4; special attention needs to be paid to PAHs in the study area.