典型工业区周围土壤重金属污染评价及空间分布

Assessment of heavy metal pollution and characteristics of its spatial distribution in soil near the typical industry area

以沈阳冶炼厂厂区及其周围土壤为对象,研究土壤重金属污染状况及其空间分布特征.结果表明,调查区域表层土壤(0-20 cm)中,Cd、Pb、Cu和Zn浓度范围分别在7.25-81.20,562.92-1014.10,289.70-527.93,673.36-1021.60 mg/kg,其平均含量分别为国家土壤质量二级标准(GB15618-1995)的74.92,2.27,4.07和3.15倍,污染程度呈现出Cd>Cu>Zn>Pb的特征.在空间分布方面,受人为与环境气象因子的共同影响,原沈阳冶炼厂厂区周围土壤中Cd、Pb、Cu、Zn 4种重金属污染带的空间分布特征呈西北至东南方向分布,西北方向土壤污染最为严重,东北至西南方向和正东至正西方向较轻.4种重金属中,Zn的污染范围最大,Cd污染在空间分布上主要集中于污染点源附近,Pb和Cu的空间分布介于Cd和Zn之间.

This paper investigated the characteristics of heavy metal concentration and spatial distribution in urban soils by collecting soil samples around Shenyang Metal Smeltery. The ranges of heavy metal concentration in the surface soil （0 -20 cm） were 7.25 -81.20,562. 92 - 1014. 10,289. 70 -527. 93 and 673.36 - 1021.60 mg/kg dry soil for Cd, Pb, Cu and Zn, respectively. The mean contents of Cd, Pb, Cu and Zn in soils were respectively 74. 92,2. 27,4. 07 and 3. 15 times of that of the second grade for heavy metals in Environmental Quality Standards for Soils （GB 15618 - 1995 ） issued by China EPA, which represented the pollu- tion degree as the order of Cd 〉 Cu 〉 Zn 〉 Pb. As regarding the aspect of heavy metal distribution in the studied area, heavy metal concentration was greater in the region from the northwest to the southeast but deceased in the region from the northeast to the southwest, the maximum in the area lying in the northwest. Among the four heavy metals Cd, Pb, Cu and Zn, Zn was distributed in the investigated over the greatest distance, Cd only dispersed near the point resource, while Pb and Cu were in the spatial range between Cd and Zn.