芜湖市交通区表层土壤多环芳烃与黑碳研究

采集芜湖市交通区和对照绿地共40个表层土壤（0~5cm）样品.应用气相色谱-质谱联用仪（GC-MS）测定样品中26种多环芳烃（PAHs）及甲基多环芳烃的浓度，应用化学热氧化法（CTO-375，BC_CTO）、湿化学氧化法（K₂Cr₂O₇/H₂SO₄，BC_Cr）分别测定样品中黑碳（BC）的含量，分析交通区表层土壤PAHs、BC的分布特征、影响区域、相互关系，并利用石油污染指标、多特征比值、正定矩阵因子分解法（PMF）对表层土壤样品中的PAHs进行来源解析.结果表明：表层土壤中PAHs、BC_Cr、BC_CTO的含量均值分别为3.63μg/g，10.23g/kg，2.93g/kg，浓度范围分别为0.075~28.76μg/g，3.78~27.13g/kg，1.07~10.36g/kg.土壤中PAHs、BC的浓度受距路远近影响，距路越近，浓度越高；且呈现出重要交通节点、路口 > 干路、支路 > 绿地的趋势，干支路无显著差异；车流量不是影响交通区土壤PAHs、BC浓度的决定因素，车辆的运行状态是其主导因素.土壤中PAHs以中高环为主.表层土壤中PAHs与两类BC都具有较好的相关性，对照绿地相关性不显著，表明BC对PAHs在土壤中的累积有重要影响，但受其他因素干扰.源解析表明表层土壤样品中PAHs主要来源于交通源.

Polycyclic aromatic hydrocarbons and black carbon in surface soil from traffic areas in Wuhu,China

Concentrations of 26 polycyclic aromatic hydrocarbons(PAHs) including EPA 16 priority PAHs were determined in forty surface soils from traffic areas and control green spaces in Wuhu, China. Black carbon (BC) was also quantified by both methods of chemical oxidation (dichromate, BC_Cr) and chemo-thermal oxidation (CTO-375, BC_CTO). The distribution characteristics, affected areas of, and relationship between PAHs and BC were discussed. Besides, the sources of PAHs in the soil were analyzed by using the compositional analysis positional analysis, methyl phenanthrene index, and positive matrix factorization (PMF) model. The results showed that concentrations of PAHs, BC_Cr and BC_CTOranged from 0.075 to 28.76μg/g, 3.78 to 27.13g/kg, and 1.07 to 10.36g/kg, respectively. Concentrations of PAHs and BCs in the soil decreased with the distance from the road. There existed a clear trend in concentrations of PAHs and BCs:important traffic nodes≈intersections > main roads≈feeder roads > greenbelts. The traffic flow was not the dominated factor for the concentrations in the traffic areas, while the running state of the vehicle was the key factor. 4~6 rings PAHs, as expected, dominated in surface soil of traffic areas. Concentrations of PAHs in the surface soil of traffic area were significantly correlated with BC_Cr and BC_CTO rather than TOC, and those in the surface soil of greenbelts had no significant correlation with TOC, BC_Cr and BC_CTO. It was showed that BC had an important influence on the accumulation of PAHs in the soil, but was interfered by other factors. In addition, the PAHs in the soil samples mainly originated from the transportation source.