西安市大气悬浮颗粒物致突变性及其金属特征

目的　了解西安市采暖期和非采暖期的大气总悬浮颗粒物 (TSP)浓度、有机提取物的致突变性及无机提取物中Pb、Mn、Cr、Ni、Cd等金属元素特征。方法　根据西安市城市功能分区 ,用网格式布点法选择了 4个大气质量监测点 ,于采暖期和非采暖期共采集大气悬浮颗粒物样品 96份 ,分别采用增重法、Ames试验—平板掺入法和火焰原子吸收法 ,对样品中大气TSP浓度、有机提取物的致突变性及无机提取物中Pb、Mn、Cr、Ni、Cd等金属元素含量进行测定。结果　西安市采暖期大气TSP浓度为 0 .5 865mg·m-3,非采暖期为 0 .3 5 3 5mg·m-3(P <0 .0 5 ) ,且两期TSP浓度均显著高于其各自对照区 (P <0 .0 5 )。各采样点TSP的有机提取物致突变性检测结果显示各功能区均可检出致突变阳性样品 ,同一季节各监测点致突变阳性检出率无显著性差异 (P >0 .0 5 ) ,但采暖期致突变阳性检出率显著高于非采暖期 (P <0 .0 5 )。各采样点TSP无机提取物中 5种金属元素浓度由高到低依次为Pb、Mn、Cr、Ni、Cd。采暖期各金属元素浓度显著高于非采暖期 (P <0 .0 5 )。结论　西安市大气TSP水平与采暖燃煤关系密切 ,燃煤可能是造成西安市大气TSP致突变性增强的主要原因之一

A study on the mutagenicity of organic extracts and metal features of TSP in Xi'an City

Objective To study the concentration, mutagenicity of organic extracts and the Pb, Mn, Cr, Ni and Cd metal element features of total suspended particulates (TSP) in heating and unheating seasons in Xi'an City. Methods According to the distribution of the city functional districts, four surveillance spots were chosen by the method of grid. The concentration, mutagenicity of organic extracts and the Pb, Mn, Cr and Cd metal element features were investigated in 96 TSP samples obtained from two seasons by means of increasing weight, Ames test-planer penetration and atomic absorption spectrophotometry, respectively. Results In heating and unheating seasons, the TSP concentration were 0.5865mg·m -3 and 0.3535mg·m -3, the former significantly higher (P< 0.05), and the TSP concentration in the two seasons was also higher than that of the control group of themselves (P< 0.05). The positive mutagenicity of organic extracts were tested in all functional sampling spots, and the positive rate in heating period was significantly higher than that in unheating season (P< 0.05), but there was no difference among the same season samples (P> 0.05). The concentration level sequence of five metal elements were Pb, Mn, Cr, Ni and Cd from high to low, and the individual concentration in heating season was higher than unheating period (P< 0.05). Conclusion There is a close relationship between the TSP concentration and the coal consumption, and the coal consumption is probably major factor enhancing the mutagenicity of TSP in Xi'an City.