Minxia Liu

Concentration, Distribution, Source, and Risk Assessment of PAHs and Heavy Metals in Surface Water from the Three Gorges Reservoir, China

ABSTRACT Fifteen polycyclic aromatic hydrocarbons (PAHs) and heavy metals (Cr, Ni, As, Cd, Pb, and Hg) were quantified in 19 surface water sites of the Three Gorges Reservoir, China. The total concentrations of 15 PAHs and six heavy metals in the 19 sample sites ranged from 130.8 ng L−1 to 227.5 ng L−1 and 3.2 μg L−1 to 6.0 μg L−1, respectively. The mean concentration of As was the highest among the six heavy metals (2.1 ± 0.3 μg L−1), followed by Cr (0.5 ± 0.3 μg L−1), Ni (1.3 ± 0.1 μg L−1), Cd (0.2 ± 0.01 μg L−1), Pb (0.07 ± 0.08 μ g L−1) and Hg (0.05 ± 0.08 μg L−1). The isomer ratio results suggest that PAHs at most sites were mainly from petroleum combustion, while coal and biomass combustion was the main source at sites 1, 2, 6, 7, 9, 14, and 17. Based on principal component analysis, the main source of heavy metals was anthropogenic activities and weathering of bedrocks. Depending on characteristic of RQ(NCs) ≥ 1 and RQ(MPCs) < 1, BaA showed higher potential ecological risk than other PAHs, therefore, all sampling site needed to be paid much more attention, included some remedial actions. Meanwhile, after assessing human health risk of heavy metal, it was unlikely to experience adverse health effects, even exposing through more pathways and six kinds of heavy metals simultaneously.

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.