太原市干沉降中PAHs污染特征及生态风险研究

Study on the Pollution and Ecological Risk of Polycyclic Aromatic Hydrocarbons Based on the PCA Model in Dry Deposition

研究使用大气干湿沉降自动采样仪于2013年8月至2014年10月采集了太原市30个大气干沉降样品,并对15种USEPA优控多环芳烃(PAHs)的污染特征和来源及生态风险进行了研究。结果表明太原市干沉降中∑15-PAHs的水平为(8.19~62.31)μg/g,均值为24.37μg/g,污染水平较高;PAHs主要组成成分为Phe、Fla、Pyr和chr,环数以3、4环为主。特征比值法和主成分分析结果显示太原市干沉降中PAHs的三大主要来源为燃煤、机动车和焦化产业。干沉降通量和∑15-PAHs的干沉降通量范围分别为(157.44~358.17)mg/(m^(2)·d)和(2436.20~13616.80)ng/(m^(2)·d),太原市全年颗粒物和∑15-PAHs沉降量为6.89×10^(5)t和18.18 t.干沉降中PAHs的毒性当量浓度范围为(0.67~2.94)μg/g,均值为1.55μg/g.生态效应区间法评价结果显示82.76%的干沉降样品所含PAHs生态风险水平较高,应引起高度重视。

In this study,thirty atmospheric dry settlement samples were collected in Taiyuan city from August 2013 to October 2014 with the automatic sampling instrument for atmospheric dry settlement,and the pollution characteristics,sources and ecological risks of fifteen USEPA optimized polycyclic aromatic hydrocarbons(PAHs)were studied.The results showed that the∑15-PAHs level in dry deposition in Taiyuan city was(8.19~62.31)μg/g,with the mean of 24.37μg/g,the pollution level was higher comparing with other studies.The PAHs were composed of 3-and 4-rings PAHs,and the dominant components were Phe,Fla,Pyr and Chr.Fluxes of particulate matter and PAHs in dry deposition were(157.44~358.17)mg/(m^(2)·d)and(2436.20~13616.80)ng/(m^(2)·d),respectively.The annual estimated results showed that about 6.89×10^(5)tparticles and 18.18 t∑15-PAHs reached the surface by dry deposition in Taiyuan city.The isomeric ratios and principal component analysis indicated that PAHs in dry deposition were derived primarily from the coal combustion,motor vehicle emissions and coking emissions.The toxic equivalent concentrations of PAHs in dry deposition ranged from(0.67~2.94)μg/g,with a mean of 1.55μg/g.It was found that PAHs in 82.76%of the dry deposition were at moderate ecological risk using the ecological effect interval method,which should be paid more attention to.