大气中痕量持久性有机污染物年均值的测定

Determination of Annual Average of Trace Persistent Organic Pollutants in Air

采用以XAD-2树脂为吸附介质的大气被动采样器,在四川卧龙自然保护区设置6个采样点,进行了为期2年(2005年—2007年)的环境大气样品采集。用气相色谱-高分辨质谱方法对HCB,HCHs,DDTs和PCBs测定。结果表明,平行样品的重现性良好,平均相对偏差为9%。POPs检测下限的范围为1.0 pg/m3～5.9 pg/m3。2年的年均值数据表现出较好的一致性和规律性。以XAD-2树脂为吸附介质的大气被动采样器能够便利地采集进而测定半年或一年污染物的平均浓度,可以经济、有效地获得大气中痕量POPs的年均值。ρ(α-HCH)/ρ(γ-HCH)从成都到卧龙的上升的趋势反映的是传输过程中HCH的降解;而卧龙地区跨年度数据所反映出的ρ(α-HCH)/ρ(γ-HCH)下降趋势,可以归因于林丹的使用。

In this paper using XAD-2 resin based passive air samplers （PAS）, we installed six sampling sites in Wolong Natural Reserve. Annual averages of persistent organic pollutants in air were determined in 2005--2007. Organochlorine compounds such as HCB, HCHs, DDTs and PCBs were determined by the gas chromatography-high resolution mass spectrometry method. The relative difference between PAS duplicates was usually less than 9% and acceptable. The detection limits for POPs fell in the range of 1.0 pg/m^3 to 5.9 pg/m^3. Annual averages of two consecutive years show good consistence and regularity. With the XAD-2 resin based passive air samplers; it is feasible to determine cost-effectively the average concentrations of POPs fur one year or half a year. The increasing trend of ρ（α-HCH）/ρ（γ-HCH） ratio, from Chengdu plain to Wolong mountain, reflects the degradation of HCH in transport; and the decline of ρ（α-HCH）/ρ（γ-HCH） ratio over two consecutive years could be attributed to the use of lindane in Chengdu plain.