西安市公园土壤多环芳烃污染特征、来源及风险评价

Assessment of Pollution,Sources,and Risks of Polycyclic Aromatic Hydrocarbons in Soil from Urban Parks in Xi'an City,China

应用高效液相色谱仪测定了西安市17个公园土壤样品中16种优控多环芳烃(PAHs)的含量,并分析了PAHs的组成、污染水平、来源、生态与健康风险.结果表明:样品中ΣPAHs含量在0.362~1.336μg·g^(-1)之间,平均值为0.591μg·g^(-1),其中7种致癌多环芳烃(Σ_7CPAHs)的含量范围为0.051~0.528μg·g^(-1),均值为0.181μg·g^(-1).与国内其它城市表层土壤比较发现西安市公园土壤均受到PAHs污染但程度较轻,PAHs主要由2~3环的低环PAHs构成.源解析结果表明,公园土壤中PAHs主要来自于石油燃烧,个别样点来源比较复杂多样,为石油泄漏、石油燃烧、煤和生物质等不完全燃烧的混合源.效应区间低值(ERL)法和效应区间中值(ERM)法评价结果表明,公园土壤存在PAHs污染,但潜在生态风险性较低.终生癌症风险增量(ILCRs)模型评价结果显示,儿童和成人的健康风险都在可允许的范围内,对儿童的健康威胁高于成人,3种暴露途径中皮肤接触土壤PAHs是导致高风险的最主要暴露途径,ILCRs皮肤接触分别占其3种暴露途径的总风险(CR)的63.98%(成人)和55.49%(儿童);其次是误食土壤PAHs暴露途径,分别占CR的36.02%(成人)和44.51%(儿童).

A total of seventeen surface soil samples were collected from urban parks in Xi＇an city.The concentration of sixteen priority polycyclic aromatic hydrocarbons（PAHs） were analyzed by high performance liquid chromatography（HPLC）.In addition,the composition,source,pollution level and a risk assessment of PAHs in surface soil of park were evaluated.The results showed that the total concentrations of sixteen PAHs ranged from 0.362 to 1.336 μg·g^-1,with a mean value of 0.591 μg·g^-1.The concentration of seven carcinogenic PAHs（Σ7CPAHs） ranged from 0.051 to 0.528 μg·g^-1,with a mean value of 0.181 μg·g^-1.Compared to theΣ PAHs levels of other cities of China,the Σ PAHs in park surface soils in Xi＇an are relatively low.PAHs in the soil samples were dominated by low molecular weight PAHs with 2 and 3 rings.The results of source analysis showed that the PAHs in park surface soil mainly originated from the combustion of fossil fuels,however,the source of PAHs in some samples is complex and from mixed sources,such as oil spills,oil burning,and incomplete combustion of coal and biomass.The ecological risks of PAHs in the surface soil were evaluated according to the soil quality guidelines to be ERL（effects range low） and ERM（effects range median）,and these results showed that all samples,in general,were polluted.However,the potential ecological risks of PAHs were at a low level.The incremental life cancer risk（ILCR） assessment indicated that health risks for children and adults were both in a permissible range,however,the risks for children exposed to the soil were considerably higher than for adults.Dermal contact was the main exposure pathway that resulted in the relatively higher risk,followed by ingestion.