葫芦岛市土壤、蔬菜重金属污染空间变化规律

Spatial Variation of Heavy Metals Contamination in the Soil and Vegetables of Huludao City

采用Krige插值法分析葫芦岛市土壤重金属的空间变化规律,测定葫芦岛市土壤、蔬菜、粮食中Hg、Pb、Cd、Zn、Cu的含量,应用指数方程和幂指数方程描述重金属与污染源的关系,分析土壤重金属的来源,并通过对当地种植和市售蔬菜、粮食重金属的比较,研究冶炼-氯碱工业对土壤与农作物生态系统的影响.结果发现葫芦岛市土壤受到重金属污染严重,Hg、Pb、Cd、Zn、Cu的平均含量分别是1.422、443.1、60.94、4084、247.8mg·kg-1,最大值分别达到6.092、3195、341.7、35157、1557mg·kg-1,Cd、Zn污染属于重污染,Hg、Pb、Cu属于中度污染.土壤中Hg、Pb、Cd、Zn、Cu的污染主要呈现以葫芦岛锌厂为中心,向外围辐散降低的规律,其中Hg还受到氯碱工业的影响.葫芦岛市土壤重金属主要来源于大气沉降,指数方程和幂指数方程均能很好地描述Pb、Cd、Zn、Cu在土壤中随距离的变化趋势.地产农作物的重金属含量远高于市售农作物,则进一步说明了重金属对葫芦岛市土壤生态系统带来了严重影响.

Hg, Pb, Cd, Zn, and Cu concentrations in the soil, vegetables and crop of Huludao city were investigated. The Hg, Pb, Cd, Zn, and Cu concentrations in soils of the smelting areas are 1.422, 443.1, 60.94, 4084, and 247.8 mg·kg^-1, thus 6.092, 3 195, 341.7, 35 157, and 1 557 mg^kg^-1 for the maximal concentrations, respectively. Spatial distribution maps of heavy metals concentrations in top soils in Huludao City were separately laid out by using Kriging. Heavy metals spatial distribution patterns in soils show that Pb, Cd, Zn, Cu emissions from Huludao Zinc Plant are the main pollution sources of heavy metals to the top soils in Huludao City, but Hg emission from Huludao Zinc Plant and chlor-alkali industry is the main pollution source of mercury to the top soils. Heavy metals concentrations in top soils decrease exponentially with distance from the zinc smelting area. Except Hg, the exponential equation could be better to fit the variety for other heavy metals. Heavy metals in vegetable and crop cultivated around Huludao Zinc Plant are higher than from markets, suggests that heavy metals affect the local soil and crops seriously.