贵阳市不同粒级地表灰尘中As、Ni水平及权重

根据贵阳市城区土地利用的情况,在不同功能区地表采集灰尘样品,分析As、Ni含量及变异规律。结果表明:贵阳市地表灰尘As、Ni含量分别为17.4mg/kg和50.0mg/kg。工业区地表灰尘中As、Ni含量最高,商贸区和校园等区域As、Ni水平较低。贵阳市地表灰尘中不同颗粒物的质量百分比大小为细颗粒(<105μm)>中等颗粒(105～250μm)>粗颗粒(250～425μm)。As在不同粒径灰尘中含量差别不大,Ni在不同粒径灰尘中含量随粒径增加而降低。细颗粒对灰尘As、Ni的贡献分别为42%和47%。除垃圾站外,贵阳市各功能区地表灰尘不同粒径颗粒物百分比随粒径增大而减小,其中交通区地表灰尘细颗粒所占比例最大。垃圾站地表灰尘中不同粒径颗粒百分比则随粒径增大而增大,As、Ni在垃圾站地表灰尘中颗粒物贡献为中等颗粒>粗颗粒>细颗粒,其余功能区不同粒径颗粒物的贡献基本为细颗粒大于粗颗粒。

The Level of As and Ni in Street Dust Fractions of Different Sizes and Its Contributions in Guiyang

Based on the land use status in Guiyang,a total of 66 dust samples from industrial area(IA),residential area(RA),traffic area(TA),city square(CS),school area(SA),commercial area(CA) and garbage stations(GS) were collected within the central urban area of Guiyang for assessing the distribution of As and Ni and its difference.The results showed that the industrial area represented the highest mean level of As and Ni,and the commercial area and school area had relatively low mean level of As and Ni.The mass percentage of street dust fractions of different sizes follows the order of fine fraction(<105 μm)> medium fraction(105～250 μm)> coarse fraction(250～425 μm).Differences in the distribution of As in street dust fractions of different sizes in Guiyang are not significant,while Ni in street dust fractions of different sizes in Guiyang decreases with increasing particle size.Street dust of Guiyang shows a relatively high mass percentage of As(42%) and Ni(47%) in fine fractions(<105 μm).Except garbage stations,the mass percentage of street dust fractions of different sizes in other function areas decreases with increasing particle size,and the traffic area has the highest value of mass percentage in fine fractions.The mass percentage of street dust fractions of different sizes in garbage stations increases with increasing particle size.The contributions to As and Ni in street dust fractions of different sizes in garbage stations follows the increasing order of e medium fraction> coarse fraction>fine fraction.In the other function areas,the contributions to As and Ni from fine fractions of dust in Guiyang are higher than those from the medium and coarse fractions.