河南省高速公路中央分隔带土壤多环芳烃污染特征及风险评价

Pollution and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Central Separate Belt of Expressway in Henan Province

为了解高速公路中央分隔带多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的污染现状和潜在风险,本研究采集了河南省3条高速公路中央分隔带11个样点的土壤,测定了其中16种PAHs的含量,分析了PAHs的污染特征,探讨了PAHs的生态风险。结果表明,高速公路中央分隔带土壤中PAHs总浓度范围为5253.33~65072μg·kg^(-1),平均值为19873.1μg·kg^(-1);其中,低环PAHs占总PAHs的42.46%,高环PAHs占总PAHs的57.54%;此外,2号和7号采样点比其他9个采样点PAHs污染严重。生态风险评价结果显示,高速公路中央分隔带土壤均被PAHs污染,且72.72%的污染土壤属于中等以上生态风险。健康风险评价结果表明,高速公路中央分隔带土壤PAHs对儿童和成人均存在较大的致癌风险,主要暴露途径为皮肤接触和摄食。PAHs组分特征结合来源分析结果表明,低环PAHs主要来源于重型车的柴油燃烧;高环PAHs主要来源于小型轿车的汽油燃烧。相关性分析结果显示,大部分高速公路中央分隔带土壤中的PAHs,尤其是高环PAHs,与有机质(soil organic matter,SOM)呈显著正相关,与阳离子交换量(cation exchange capacity,CEC)、全氮(total nitrogen,TN)和pH呈显著负相关。

In order to analyze the pollution status and potential risk of polycyclic aromatic hydrocarbons(PAHs)in the central separate belt of expressways,11 soil samples were collected from 3 expressways in Henan Province,and the amounts of 16 PAHs were determined.In addition,the pollution characteristics and ecological risk of PAHs were also evaluated.The results showed that the total PAHs content in the central separate belt of expressways soils ranged from 5253.33 to 65072μg·kg^(-1),with a mean value of 19873.1μg·kg^(-1).Among them,low and high-ring PAHs accounted for 42.46%and 57.54%,respectively.In addition,sampling sites 2 and 7 were more polluted by PAHs than the other 9 sampling sites.The ecological risk assessment results indicated that the soils in the central separate belt of expressways are polluted by PAHs,with 72.72%of the polluted soils posing medium or higher ecological risks.The health risk assessment showed that the soil posed a greater risk of carcinogenicity to both children and adults,and the main exposure routes were skin contact and ingestion.The characteristics of PAHs component combined with the source analysis showed that low-ring PAHs are mainly from diesel engine combustion of heavy vehicles,and high-ring PAHs are from gasoline engine combustion of small cars.The correlation analysis indicated that the PAHs,especially high-ring PAHs,were significantly positively correlated with soil organic matter and negatively correlated with cation exchange capacity,total nitrogen,and pH.