自贡市城区大气PM2.5中多环芳烃污染特征及健康风险评价

Characteristics and health risk assessment of polycyclic aromatic hydrocarbons in atmospheric PMin Zigong

目的了解自贡市城区大气PM2.5中多环芳烃(PAHs)污染水平、主要来源及其对人群的健康风险。方法2017年1—12月采集自贡市城区大气PM2.5样品172份,用高效液相色谱法检测PM2.5中16种PAHs浓度,分析其变化规律,用特征比值法探讨PAHs的来源,采用美国EPA推荐的健康风险模型评价人群健康风险。结果大气PM2.5平均浓度为79.3μg/m3,范围为45.9~152.5μg/m3。16种PAHs均有检出,PAHs总浓度的平均值为229.9 ng/m3,范围为36.6~1022.2ng/m3。PM2.5浓度和16种PAHs的总浓度随季节的变化规律一致,均为冬季>秋季>春季>夏季,四季PAHs的组成以4~6环为主。PAHs的主要来源为机动车尾气排放和燃煤。PAHs的总致癌等效浓度和总致突变等效浓度的平均值分别为4.57、3.71 ng/m3,PAHs通过呼吸暴露对成人和儿童造成的预期寿命损失分别为10.19、6.71 min。结论自贡市2017年大气PM2.5中PAHs污染以冬季最为严重,对健康可能有潜在风险。

Objective To investigate the pollution levels and sources of polycycle aromatic hydrocarbons(PAHs)in the atmospheric PM2.5 in urban areas of Zigong,Sichuan province and assess the health risk assessment in population.Methods The PM2.5 samples were collected in Zigong from January to December during 2017,and 16 PAHs in PM2.5 were analyzed by high-performance liquid chromatography,and their variations and sources were investigated,the health risks were evaluated by EPA-recommended model.Results The monthly average concentration of PM2.5 was 79.3μg/m3,with a range of 45.9-152.5μg/m3.A total of 16 PAHs were detected in PM2.5.The contents of total PAHs ranged in 36.6-1022.2 ng/m3 with the average level of 229.9 ng/m3.The contents of PM2.5 and total PAHs had the same change trends with the seasons.The highest level of total PAHs appeared in winter,followed by the order of autumn>spring>summer;The distributions of PAHs were largely composed of 4-6 rings;Characteristic ratios method suggested that the PAHs in PM2.5 were mainly from motor vehicle exhaust and coal burning.The average concentration of toxic equivalent quantity(TEQ)and mutagenic equivalent quantity(MEQ)were4.57 ng/m3 and 3.71 ng/m3 respectively.The loss of expectation of life by PAHs through respiratory exposure for adults and children were 10.19 min and 6.71 min.Conclusion In 2017,the pollution of PAHs in PM2.5 in Zigong is the most serious in winter,and it has potential risk to human health.