玉溪市大气颗粒物中PAHs污染特征与健康风险评估

Pollution characteristics and health risk assessment of PAHs in atmospheric particulates in Yuxi City

2014年8月至2015年7月,在玉溪市主城区6个采样点采集了大气颗粒物(PM10)样品,利用高效液相色谱法对颗粒物上载带的16种多环芳烃进行测定.结果表明,玉溪市主城区PM10中的多环芳烃总浓度(∑PAHs)范围为2.83—78.30 ng·m-3,年平均值为(13.92±10.69) ng·m-3,其中工业区代表中的大营街(DY)采样点浓度最高,达到(16.15±11.57) ng·m-3.PAHs浓度的季节变化规律表现为冬季>秋季>春季>夏季.利用特征比值和主成分分析得出,PAHs的污染来源主要包括机动车排放和燃煤源(48.26%—63.66%)、生物质燃烧(16.1%—26.16%)、木材燃烧(16.1%—18.1%)和焦炭燃烧源(9.54%—11.36%).BaP等效毒性当量浓度(BaPeq)在秋冬季超出国家环境空气质量二级标准日均限值2.5 ng·m-3.通过终身致癌风险模型(ILCR)评估PAHs对人群的健康风险,发现玉溪市大气颗粒物PM10中PAHs的儿童吸入风险均处于可接受范围,但在秋季的玉溪一中(YX),冬季的研和工业区(YH)和市监测站(SJ)采样点的成人健康风险水平还需加强防范.

A series of PM10 samples were collected at six sampling sites in Yuxi city from August 2014 to July 2015, and 16 priority controlled PAHs were analyzed by HPLC. The results showed that the total concentrations of PM10-bound PAHs(∑PAHs) in YuXi city ranged from 2.83 to 78.30 ng·m-3, with the annual average of(13.92±10.69) ng·m-3.The concentration in DY(industrial area) was the highest, reaching(16.15±11.57) ng·m-3. The seasonal variation of PAHs concentrations was: winter>autumn>spring>summer. Diagnostic ratios and principal component analysis revealed that the PAHs sources mainly came from the vehicle emissions and coal combustion(48.26%—63.66%), followed by biomass burning(16.1%—26.16%) and wood burning(16.1%—18.1%),while the contribution of coke combustion(9.54%—11.36%) was relatively low. Bap toxicity equivalent(BaPeq) exceeded the daily limit of the national ambient air quality secondary standard(2.5 ng·m-3)in the autumn and winter. Potential health risks of PAHs was characterized by calculating incremental lifetime cancer risk(ILCR) and the result showed that the inhalation risk of PAHs in PM10 was in an acceptable range to children, while the adult health risk needed more attention in the autumn of YX site and the winter of the YH site and SJ site.