西安市各功能区7月大气降尘中多环芳烃污染特征及风险评价

为了解西安市7月大气降尘中多环芳烃(PAHs)的污染特征,在对西安市各功能区7月大气降尘样品采集的基础上,测定分析了样品中PAHs的含量、组成、来源、生态健康风险及其与总有机碳(TOC)的关系。结果表明:(1)西安市7月大气降尘中PAHs为0.92～20.60μg/g,平均值为8.10μg/g,其中荧蒽、菲、芘、和苯并a]芘含量相对较大。各功能区大气降尘中PAHs主要以4环为主。(2)PAHs与TOC之间存在显著相关性,而各单体PAHs与TOC呈现不同程度的相关性。(3)西安市7月大气降尘中PAHs主要来源于机动车排放、燃煤和低温燃烧。(4)依据终生癌症风险增量(ILCR)模型,大气降尘中PAHs对不同暴露人群的风险值均为10^-6～10^-4,存在人体可耐受致癌风险。生态风险评价显示,大气降尘中PAHs污染存在潜在生态风险。

Pollution characteristics and risk assessment of PAHs in July dustfall from different functional areas in Xi'an

To understand the pollution properties of polycyclic aromatic hydrocarbons(PAHs)in July atmospheric dustfall of Xi’an,the concentration,composition,source,ecological and health risk of PAHs,as well as the relationship between PAHs and total organic carbon(TOC)were analyzed based on the dustfall samples collected from different functional areas of Xi’an in July.The results show that:(1)the content of PAHs in the samples ranged from 0.92 to 20.60μg/g with an average of 8.10μg/g.The contents of fluoranthene,phenanthrene,pyrene,chrysene and benzoa]pyrene were relatively large.PAHs in dustfall from different functional areas mainly composed of 4 rings.(2)There was significant correlation between PAHs and TOC,while the correlations between individual PAHs and TOC were different.(3)Source identification showed that the PAHs in July dustfall from Xi’an mainly originated from motor vehicle exhaust,coal burning and low temperature combusition.(4)The incremental life cancer risk(ILCR)values for different exposure groups ranged from 10^-6 to 10^-4,indicated that people’s health was at tolerable risk from exposer to the PAHs.The ecological risk assessment indicated a potential ecological risk of PAHs pollution dustfall.