哈尔滨沙尘暴的化学特征及其物质源探讨

对哈尔滨2002年3月20日的沙尘沉降物进行了收集。地球化学元素分析表明,哈尔滨沙尘暴沉降物化学成分以SiO2、Al2O3和Fe2O3为主,三者之和达77.8%,比兰州沙尘暴沉积物高8.72%,比兰州黄土高7.06%。V、Rb、Nb、Ba等微量元素含量要明显高于兰州沙尘,而Ni、Cu、Pb、Zn、As、Sr则低于兰州沙尘。Ca、Na、Sr元素的富集因子明显小于1,为亏损元素;Mg、K、Si、Fe、Mn、P、Ti、Co、Ni、V等元素的富集因子都在1左右,主要是地壳来源,来源于地表土的风力起尘。Cu、Pb、Zn、Cr、Se等元素有一部分来自于地壳源之外的其他污染源;As、Cd和Sb元素的富集因子大于10,为大气污染来源。沙尘的化学组成及富集因子、判别函数、物源指数、地表土的粘粒率、化学风化指标等分析表明,西北黄土的元素组成非常接近兰州沙尘,而明显不同于哈尔滨沙尘,哈尔滨沙尘源区不同于西北黄土及兰州沙尘,其气候生物状况和化学风化程度要明显好于或高于西北沙尘源区。

Chemical characteristic of duststorm deposits in Harbin and its matter origin

The sand dust precipitation was collectied in Harbin city on Mar.20,2002.The paper deals with chemical composition of Harbin dustfall deposits.The result shows that the major elements of SiO_(2)and Al_(2)O_(3) and Fe_(2)O_(3),predominate the dustfall Harbin,occupied 77.8% altogether.The contents of the trace elements such as V,Rb,Nb and Ba evidently are higher than those in Lanzhou dustfall,and the elements of Ni,Cu,Pb,Zn,As and Sr are lower than Lanzhou dustfall.The enrichment factor of Ca,Na and Sr is below 1 being deficit elements,and that of Mg,K,Si,Fe,Mn,P,Ti,Co,Ni and V elements is around 1,derived mainly from lithosphere.Part of Cu,Pb,Zn,Cr and Se is derived from other pollution sources.The enrichment factor of As,Cd and Sb is above 10,derived from pollution sources.The elemental compositions of Lanzhou dustfalls are closer to Lanzhou Loess than Harbin dustfalls,judged from discriminant function(DF) and PI.The Si/Al and Si/(Al+Fe) ratios of Harbin dustfalls are greater than the Earth's surface soils of Northwest China,and chemical weathering degrees of Harbin dustfalls are obviously higher than Lanzhou Loess and Lanzhou dustfalls.Based on the analysis of the chemical composition,discriminant function,PI,cosmid ratio of surface soils and chemical weathering index,the results indicate that element compositions of Northwest Loess are similar to Lanzhou dustfall deposits,while they are obviously different from Harbin sanddust.The source areas of Harbin sanddust differ from Northwest Loess and Lanzhou sanddust,and the status of climate and biology and the degree of chemcial weathering are much better than sanddust sources in Northwest.