北京冬季大气颗粒物中铅的同位素丰度比的测定和来源研究

Determination of Isotope Abundance Ratio of Lead in Beijing Atmospheric Aerosol and Lead Source Study

本文报道了北京市冬季（1998-1999年）大气颗粒物样品的无机多元素和铅同位素丰度比的测定数据。分别采用HR-ICP-MS和TOF-ICP-MS测定铅同位素丰度比,结果表明ICP-MS的测定精度可适用于大气中铅的来源研究。大气颗粒物样品中一些特征无机元素含量,如Br、Ti、Pb、Zn,与铅的同位素丰度比之间存在相关性。在铅含量高的样品中机动车尾气排放的贡献明显,在铅含量低的样品中土壤扬尘和燃煤飞灰的贡献增加;其中部分样品表现出来自西伯利来地区的长距离传输的特征。样品聚类分组结果结合气象信息可以得到合理解释。应用铅的同位素技术来研究北京市大气颗粒物中的铅的来源是可行的。

In addition to the elemental analyses,both TOF-ICP-MS and HR(CP-S were applied to the determination of lead isotope abundance ratio for atmospheric aerosol samples collected in Beijing during the winter of 1998-1999. The results indicate that ICP-MS analysitcal data can be used for the investigation of lead pollution sources. The concentrations of some characteristic elements such as bromine, titanium and lead varied systematically with lead isotope abundance ratios. Samples with higher lead content have higher contirbuiton from leaded-gasoline, while those with lower lead content have higher contribution from soil dust and coal fly ash. Some aerosol samples showed a feature of long-distance transport from Siberia. Taking meteorological conditions into account , a reasonable explanation is presented for the four aerosol sample groups obtained from cluster analysis. It is feasible to apply the lead isotope ratio as a fingerprint technique to the source study of lead pollution in Beiing.