泉州市大气降尘中金属元素污染特征及来源解析

测定了泉州市不同功能区大气降尘中23种金属元素的含量,采用多种方法对其富集程度、污染水平及生态风险进行评价,并用多元统计分析法结合Pb、Sr同位素示踪对污染来源进行解析.结果表明:泉州市大气降尘中不同金属含量空间分布差异较大;富集因子和地累积指数表明,Cd、Hg、Zn、Ca、Pb、Cu、Ni、Sr的富集程度及污染水平相对较高;生态风险指数显示,所有功能区的多元素综合潜在生态风险程度极高,由高到低顺序为工业区交通繁忙区商业区居住区风景区农业区;Cd和Hg的潜在生态危害程度极高,二者对综合潜在生态风险指数的贡献达95.56%.多元统计分析结果表明,V、Fe、Ba、Bi、Ni、Sr、Pb、Cs、Sc、Zn、Cd主要来源于工业污染和交通排放,Th、U、Rb、Y、Ti主要来源于土壤尘,Li、Mn、Cu、Hg、Cr、Co、Ca主要来源于燃煤.铅同位素三元混合模型计算得到降尘中铅来源主要为土壤母质(29.41%~64.00%)、燃煤尘(22.53%~60.48%)和汽车尾气(3.13%~13.47%);87Sr/86Sr和1/Sr分布图显示降尘中锶来源主要为燃煤尘和汽车尾气.

Characteristics and Source Apportionment of Metals in the Dustfall of Quanzhou City

Concentrations of 23 metal elements in the dustfall collected from different functional areas of Quanzhou City, China, were determined. Several methods were applied to assess the enrichment degree, pollution level and potential ecological risk of the above elements. The sources of the above elements were analyzed based on the multivariate statistical analysis combining Pb and Sr isotopic tracing technology. The results showed that the concentrations of metals in the dustfall presented significant spatial difference. The results of enrichment factor and geo-accumulation index indicated that Cd, Hg, Zn, Ca, Pb, Cu, Ni and Sr showed relatively higher enrichment degree and pollution level. The results of ecological risk index showed that the comprehensive ecological risk of heavy metals was very high in the dustfall of all functional areas with the sequence of industrial area>heavy traffic area >commercial area >residential area >scenic area >agricultural area. Cd and Hg showed extremely high potential ecological risk, and they contributed 95.56% to the comprehensive potential ecological risk index. The multivariate statistical analysis demonstrated that the elements of V, Fe, Ba, Bi, Ni, Sr, Pb, Cs, Sc, Zn, Cd were mainly from industrial and vehicle emissions; Th, U, Rb, Y, Ti were mainly derived from soil dust; Li, Mn, Cu, Hg, Cr, Co, Ca were mainly from coal combustion. The contribution ranges of parent soil, coal combustion and vehicle emission to the Pb in the dustfall were 29.41%-64.00%, 22.53%-60.48% and 3.13%-13.47%, respectively, as calculated by a ternary hybrid model; The plots of ⁸⁷Sr/⁸⁶Sr vs 1/Sr showed that Sr in the dustfall was dominated by coal combustion and vehicle emission.