从沙尘暴降尘中元素的富集因子追踪元素的来源及对环境的影响

Source of elements and its influence on environment from enrich factor of elements in settled dust of dust storm

采用中子活化法和X射线吸收-沉降法对发生在中国甘肃武威地区的一次沙尘暴降尘中的29种元素的含量进行了分析,并分别以此次沙尘暴源区、传输过程中经过地区的不同土壤类型的元素背景值为参考,分别计算了沙尘暴降尘中29种元素的富集因子,研究了不同土壤类型间元素富集因子的相关性,探讨了各元素的主要来源:元素As,Br,Ca,Cr,K,La,Sm,Ta,U,W,Zn的富集因子均大于2,说明它们可能有外来源。外来源主要是由采矿等人类活动造成。过量的这些元素随风迁移并沉积有可能污染环境并产生危害;元素Ce,Co,Cs,Dy,Fe,Mn,Na,Rb,Sc,Tb,Th,Ti,V,Yb的富集因子均接近于1(0.8～2),说明这些元素主要来自自然界本身,而且性质较稳定;元素Eu,Mg,Hf的富集因子均小于0.8,说明这些元素可能随水平移或向土壤深处下移。研究结果可作为沙尘暴对环境的影响的科学依据。

The contents of 29 elements of settled dust of dust storm occurred in Wuwei of Gansu province were measured by method of neutron activation and method of X-ray absorption-settlement.Enrich factors of 29 elements were calculated according to soil background value of elements of different soil classification of source area and passage area of migration of dust storm.Source of elements was discussed：（1）Enrich factors of As,Br,Ca,Cr,K,La,Sm,Ta,U,W,Zn are more than 2,these elements are mainly come from outside source resulted from exploitation.These elements followed by wind migration and sedimentation,and may pollute the environment and result in various harm.（2）Enrich factors of Ce,Co,Cs,Dy,Fe,Mn,Na,Rb,Sc,Tb,Th,Ti,V,Yb are from 0.8 to 2,these elements are mainly come from nature.Their character is stable.（3）Enrich factors of Eu,Mg,Hf are less than 0.8,these elements may be easily migrate followed by water.These conclusions are scientific reference when influence of dust storm on environment is studied.