太原市土壤重金属污染空间分布及评价

Spatial distribution and assessment of heavy metals from the soil of different functional areas in Taiyuan City

以太原市土壤作为研究对象,系统研究了太原市城市土壤及工业区土壤中Cr、Ni、Cu、Zn、As、Cd、Pb的污染水平和分布,并对污染状况进行了评价.研究表明,太原市土壤中重金属的含量分别为Cr:35.35—848.80mg·kg-1,Ni:4.00—99.57 mg·kg-1,Cu:4.89—266.99 mg·kg-1,Zn:45.16—677.01 mg·kg-1,As:0.66—35.46 mg·kg-1,Cd:nd—1.00 mg·kg-1,Pb:15.61—1240.41 mg·kg-1.其中城市土壤重金属含量较低,工业区土壤重金属含量较高,受到多种重金属的复合污染.以土壤环境质量国家二级标准值作为评价标准,用单项污染指数和综合污染指数对太原市土壤重金属污染进行评价,结果显示太原市大部分城市土壤未受7种重金属污染,只有6.7%的地区处于轻污染水平;工业区土壤污染严重,污染程度从高至低为化工厂(重污染)>热电厂(重污染)>化肥厂(重污染)>第一电厂(中度污染)>建筑工地(中度污染)>焦化厂(轻污染).7种重金属在太原市土壤中的空间分布规律不同,且均与工业区分布相关,工业区是太原城市土壤重金属污染的重要来源.

This study was conducted to establish the contamination status, identify the spatial distribution, and explore the pollution assessment of Cr, Ni, Cu, Zn, As, Cd and Pb in the soils from different functional areas in Taiyuan City. The concentrations of Cr, Ni, Cu, Zn, As, Cd and Pb in the soil of Taiyuan were 35. 35—848. 80 mg·kg^-1, 4. 00—99. 57 mg·kg^-1, 4. 89—266.99 mg·kg^-1, 45.16—677.01 mg·kg^-1, 0.66—35.46 mg·kg^-1, nd—1.00 mg·kg^-1, 15.61—1240.41 mg·kg^-1 , respectively. Heavy metals were not a severe component of contaminant from the urban soil. However, there was seriously higher contamination of multiple heavy metals from the soil of the industrial areas. Furthermore, the pollution assessment of the heavy metals from the soil was based on the single factor index and Nemerow comprehensive index according to Environmental Quality Standard for Soil of China （2nd level）. The analytic results revealed that there was slight heavy metal pollution in 6.7% of urban area, while there were not any heavy metal pollution in soil of other urban area. On the other hand, the soil from the industrial areas was severely polluted by these heavy metals. Results from the previous pollution assessment indicated that chemical plant, thermoelectric plant and fertilizer plant reached the heavy pollution, No.1 power plant and building site reached the moderate pollution, and coking plant reached the light pollution. The degree pollution were chemical plant 〉thermoelectric plant 〉fertilizer plant 〉No.1 power plant 〉building site 〉 coking plant. Moreover, the spatial distribution characteristics of 7 heavy metals in the soil of Taiyuan were quite different. This might be caused by the distribution of the industrial areas. The results suggested that the industrial areas were an important source of the soil heavy metals in Taiyuan.