西沙永兴岛土壤中多环芳烃的分布特征及来源

Distribution and sources of polycyclic aromatic hydrocarbons in soils from Yongxing Island,Xisha Archipelago

通过采集西沙永兴岛表层土壤和土柱样品,研究了21种多环芳烃(PAHs)在永兴岛土壤中的浓度和组成特征,对土壤中PAHs的来源进行解析,并对生态风险进行了评估。结果表明,永兴岛表层土壤中PAHs的浓度范围为38.9—176.4 ng·g^(-1),16种优控PAHs的浓度为36.7—155.6 ng·g^(-1),跟其它类似环境相比,永兴岛土壤中PAHs污染相对较轻。芘、荧蒽、菲、苯并[b]荧蒽、[艹屈]、苯并[a]芘、茚并[1,2,3-cd]芘和苯并[e]芘是永兴岛表层土壤中最主要的PAHs。永兴岛土柱中总PAHs与2—3环PAHs浓度分布特征相似,表层和底层浓度较高,2—3环PAHs在土柱中占比为74%—96%。来源解析表明永兴岛土壤中PAHs主要以石油、木材或煤等燃烧源为主。16种PAHs的等效致癌风险浓度显示永兴岛土壤中PAHs生态风险较低。

Surface soil and soil column samples were collected from Yongxing Island, Xisha Archipelago to investigate the concentration and composition of 21 polycyclic aromatic hydrocarbons (PAHs). Their source was analyzed and ecological risk of PAHs was assessed. The results showed that the concentrations of the 21 PAHs in the surface soils from Yongxing Island ranged from 38.9 to 176.4 ng·g^(-1) and the concentrations of 16 priority controlled PAHs were in the range of 36.7-155.6 ng·g^(-1). Compared with other studies, the concentrations of soils from Yongxing Island were relatively less-polluted. The major PAHs in the surface soils from Yongxing Island were PYR, FLA, PHE, B[b]F, CHR, B[a]P, I[1,2,3-cd]P and B[e]P. The concentrations of total PAHs and 2-3 rings PAHs in the soil column had a similar distribution pattern and their concentrations in the top and bottom layers were relatively higher. Soil column was predominated by 2-3 rings PAHs, accounting for 74%-96% of the total PAHs. The result of PAHs source analysis indicated that PAHs mainly came from combustion of oil, wood and coal. The Bap toxicity equivalent quantity for the 16 PAHs showed that the ecological risk of PAHs in soils from Yongxing Island was relatively low.