黑土重金属元素局地分异及环境风险

选择典型黑土3个基本样区的191个土壤样品,探讨了8种重金属元素的分异状况。结果表明,不同重金属元素,整体上存在区域差异,表层中Cu、Zn、Cr、Hg均为海伦高于其他两地,Pb为公主岭>海伦>北安;亚表层含量略有降低,分异趋同于表层。不同利用黑土的方式Cu、Zn、Cr、Hg大豆土壤高于玉米和荒地,Pb、Ni、As、Cd基本呈现玉米>大豆>荒地,整体上荒地土壤重金属含量低于耕地。与土壤理化性质的关系主要体现在公主岭地区,Cu、Zn、Pb、As与全P、全K呈相反的显性相关趋势。重金属的环境污染及潜在生态风险均为海伦>公主岭>北安,海伦地区已构成轻度污染,公主岭存在较大的潜在污染,北安土壤相对较为清洁,Cd、As、Hg在3地区均存在较大的环境风险。

Local Variation and Environmental Risk of Heavy Metals in Black Soils from the Northeast of China

The levels of 8 heavy metals from 191 soil samples obtained from typical black soils in Northeast of China were analyzed in the present survey. The results showed that the concentrations of Cu, Zn, Cr and Hg in Hailun were higher than that in Gongzhuling and Beian, respectively. The concentrations of Pb showed an order: Gongzhuling>Hailun>Beian. The contents of the heavy metals in subsoil were lower than those in topsoil and varied according with them at different sampling areas. The levels of Cu, Zn, Cr and Hg in bean soil were higher than those in corn soil and fallow, respectively, while the order of Pb, Ni, As and Cd were: corn soil> bean soil> fallow. As a whole, the concentrations in the farmland were higher than in the fallow. In addition, Cu, Zn, As, Pb had the significant positive correlation with total phosphorus and the negative correlation with total potassium in Gongzhuling. The contamination caused by the heavy metals and the potential eco- risk of the regions ranked in the following order: Hailun> Gongzhuling> Beian. There was a light pollution in Hailun, potential pollution in Gongzhuling and the soil in Beian was cleaner than that in other two areas, while a severe environmental risk induced by Cd, As and Hg was found in three sampling areas.