松嫩平原西部碱尘气溶胶的元素特征分析

Study on Element Compositions of Alkaline Dust Aerosols in Western Songnen Plain,China

碱尘暴期间松嫩平原西部碱尘气溶胶的主要元素质量浓度排序为Na、Al、Fe、Ca、Mg、K、Ti、Ba、Zn，与当地盐碱化土壤的元素组成吻合，而与沙尘、城市气溶胶的元素组成有差别。风力对碱尘气溶胶元素组成有明显的影响，当风速在8．0～17．1m／s时，元素组成的质量浓度排序为Na、Ca、Al、Fe、Mg、K、Ba、Ti、Zn。Na元素质量浓度的激增是碱尘暴元素组分的一大特征，明显富集元素为Na和B；相对于当地背景大气气溶胶的富集情况，Zn、Cu、Ba、B的富集因子值在碱尘暴期间明显降低；在各种天气情况下，B、Cu均具有较高的富集因子。碱尘中Ti元素的富集因子值均小于1，而Ca、Fe、K、Mg、Mn、Sr、V的富集因子值为1～4。两个采样点的Ca、Na、Al、Fe、Mg、Ti、Zn的富集因子近似，表明该区碱尘的主要元素具有特定的一致性；而B、Ba、Cu、V的富集因子相差较大，可以作为区分不同碱尘源的标志性元素。

The concentration of the main elements of the alkaline dust storm from Western Songnen Plain follows the decreasing order of Na, A1, Fe, Ca, Mg, K, Ti, Ba and Zn, which is compatible with the element composition of local saline soil but quite different from the normal sand dust and municipal aerosols. The relationship between wind and aerosol composition suggests that at the critical wind speed of alkaline dust storm （ADS） of 8.0～17.1 m/s,the concentration of the main elements follows the decreasing order of Na,Ca,Al,Fe,Mg,K,Ba,Ti and Zn. Enrichment factor （EF） values of element Na increase sharply during ADS, in contrast to the decrease of Zn, B, Cu etc. , which indicates that EF values of most hazardous metals are smaller during ADS periods than no ADS periods. The lower EF values of these hazardous metals during ADS periods can be ascribed to the excessive input of saline components, such as Na, Ca. EF value of Ca, Fe, K, Mg, Mn, Sr, V is around 1～4. As EF values of major elements are almost the same between two sampling sites, while the trace elements, such as B, Ba, Cu and V can be used to distinguish the dust sources because of the considerable differences between the two sampling sites.