石家庄市近地表灰尘重金属污染及环境质量评价

Assessment of heavy metal pollution and the environmental quality in the atmosphere near the ground surface of city Shijiazhuang

以石家庄市主城区为研究区,采集252个近地表灰尘样品,研究其重金属污染及环境质量状况。采用单因子指数法和尼梅罗综合指数法对石家庄城市近地表灰尘中重金属污染进行环境质量评价,最后应用ARCGIS的空间分析模块进行空间插值制图。结果表明,研究区近地表灰尘中重金属质量比均超过当地背景值,质量比变异系数较大的为Zn、Cd、Cr、Ni、Cu、Pb、Hg等,As的变异系数最小。重金属单元素污染评价表明,Zn、Cd为严重污染,Cr、Hg、Pb、Cu为潜在污染,Ni、As为清洁。重金属综合评价表明,石家庄市近地表灰尘重金属综合污染严重,重污染以上比例达到30.56%,其严重污染区与工业区域、交通分布发达程度的分布相吻合,重金属污染可能与城市的燃煤、交通等污染源有关。

The paper is to present our assessment results of htavy metal pollution and the environmental quality in the atmosphere near the ground surface of city Shijiazhuang, for which we have collected 252 atmospheric dust samples. For our assessment purpose, we have analyzed the dust samples for tracing the pollution situation by using the singlefactor contaminant index and Nemerow multifactor index method. Our study has been done based on the spatial analysis mod ule by using Aregis with a distribution map. The results of our inves tigation have shown that the actual content of all the heavy metals in the atmosphere near the ground surface of the city was beyond their o riginal background level. The variance indexes of Zn, Cd, Pb, Cu, Hg, Cr, Ni and As in the atmosphere near the ground surface of the city prove to be 382.7%, 282%, 123.9%, 189%, 92.49%, 214 % , 195.8 % , 60.6 % respectively for all the strong variance ele ments. The results of the heavy metal content affecting the environ mental quality with the singlefactor contaminant index indicate that Zn and Cd tends to be the most serious pollutants, followed by Cr, Hg, Pb and Cu as the potential ones, with Ni and As being the clean factors. The results show that the elements, according to the environ mental quality of the heavy metals with singlefactor contaminant in dex, stand in the order from the high level to low as Cd 〉 Zn 〉 Hg 〉 Cr 〉 Ni 〉 Pb 〉 Cu 〉 As. The overall impact shows the heavy metal contamination in the atmospheric dust around Shijiazhuang area is rather serious. Comprehensively speaking, the pollution degrees of the heavy metals can be stated in terms of the degrees of clean or po tentially polluted, slightly polluted, heavily polluted and severepol luted as 3.75%, 21.82%, 44.05%, 21.82%, 8.74%, respec tively. The entire pollution rate of the severe pollution situation has statistically reached 30.56 % . High content of heavy metals in the at mospheric dust has clearly been in accord with the thick distribution of industrial and developed transportation emission in and around the city area, which has close relation with the wide application of coal and petroleum in transportation and communication aspects. Needless to say, further studies are needed for the detailed causes of the con tamination,