昆明城区大气PM2.5中重金属浓度水平与健康风险研究

为探讨昆明城区大气环境PM_(2.5)中重金属的质量浓度水平和健康风险,于2013年4月、10月和2014年1月、5月在昆明市3个监测点采集PM_(2.5)样品,利用ICP-MS方法检测了8种重金属Cr、Mn、Pb、Ni、Cu、Zn、As和Cd的质量浓度水平。结果表明,昆明工业区监测点大气PM_(2.5)中Mn、Pb、Ni、Cu、Zn、As和Cd的质量浓度高于交通密集区和清洁对照点,冬春季重金属质量浓度高于夏秋季。主成分分析结果表明,昆明城区大气PM_(2.5)重金属主要来源于冶金工业源(49.43%)、地面扬尘和道路交通的混合源(18.73%)和燃煤源(12.61%)。健康风险评价结果表明,昆明城区大气PM_(2.5)中8种重金属对成人和儿童的非致癌风险均小于非致癌风险阈值1,非致癌风险最高的均为Mn,分别为9.21×10~(-3)和3.18×10~(-3);致癌风险最高的是Cr,为1.41×10~(-6),处于致癌风险安全阈值10~(-6)~10~(-4)内。

Specific features of heavy metal pollutant residue in PM2. 5 and analysis of their damage level for human health in the urban air of Kunming

The paper is aimed at making an exploration of the content concentration distributive features of the heavy metal residue in the atmospheric PM2. 5 and their risk liability that tends to be brought to human health in Kunming urban region. In the paper, we have collected PM2. 5 samples from the 3 below-mentioned monitoring sites of the city respectively in April and October (2013) as well as in January and May (2014) with the method of ICP-MS. As a result,we have detected and analyzed 8 types of heavy metal contents in PM2. 5,whose composition is of such kinds of Cr,Mn,Pb,Ni,Cu,Zn,As and Cd. The results of our analysis demonstrate that the concentrations of Mn,Cu,Pb, Zn and Ni in the industrial areas turn out to be higher than those in the comparative sanitarian sites and even traffic crowded areas. It proves consistent for the seasonal distribution of heavy metals from PM2. 5 in the areas with that of the thick transportation and traffic and the more sanitarian sites,in the distribution of Cu, Mn,Pb and As,etc. Seasonally speaking,the concentrations of spring and winter are higher while they are lower in summer and autumn. The results of the principal components analysis show that the heavy metal contents in Kunming mainly come from the three said sources. Furthermore,the labeled factors of the above mentioned sources can be attributed to the metallurgical industry (49. 43％),the mixed sources of the ground dust and the dust of road traffic (18. 73％) with coal-burning sources being of 12. 61％. And,from the point of view of their detriment to the human health,the cancer risk liability of the residue of the 8 above mentioned heavy metals in Kunming urban atmospheric PM2. 5 both on the adults and children seem to be less serious than that of cancer risk likely threshold of 1,among which Mn has the greatest non-carcinogenic risk on the adults and children (8. 71 ×10-3 and 8. 14 × 10-3 ). Nevertheless,the greatest risk of heavy metal carcinogens can be of Cr (1. 41 × 10-6 ),which is below the cancer risk threshold of 10-6-10-4. For more rigorous discussion of such risks of heavy metal exposure to the human health,the paper has made an analysis of the uncertainty of health risks through calculation and evaluation through Monte Carlo simulation.