不同剂量外源重金属注入对土壤重金属形态分布的影响

以塿土为研究对象,在添加不同剂量重金属盐的条件下,采用改进后的Tessier法测定了土壤重金属的形态,研究了不同剂量重金属盐注入后土壤重金属形态分布的变化规律。结果表明:外源重金属注入剂量的高低对塿土中Pb、Cd形态、分布影响较大,对Zn影响较小。低剂量处理后Pb形态分布为:残渣态有机结合态≈铁锰氧化物结合态交换态碳酸盐结合态;较低剂量、中剂量及较高剂量处理后形态分布为:残渣态铁锰氧化物结合态有机结合态碳酸盐结合态交换态,而高剂量处理后形态分布变为:铁锰氧化物结合态碳酸盐结合态残渣态有机结合态交换态。Cd盐处理后,低剂量和较低剂量注入后其形态分布为:残渣态铁锰氧化物结合态≈交换态有机结合态碳酸盐结合态,其他剂量注入后各形态分布呈无规律变化。不同剂量Zn盐处理后土壤中Zn形态分布始终为:残渣态铁锰氧化物结合态有机结合态碳酸盐结合态交换态。

Effect of Different Doses of Exogenous Heavy Metals on The Fractionation of Heavy Metals in Soil

TakingSlou soilSforSresearchSobjects, under the condition of adding different doses of heavy metal salts, fractionations of heavy metals were determined using improved Tessier method in soil. The change of fractionation distribution of heavy metals was studied in soil after adding different doses of heavy metals. The results showed that the level of injected dose had a large effect on the fractionation distribution of Pb and Cd in Lou soil, but a small effect on Zn. After treatment with low doses, Pb speciation distribution showed a trend in the order: residue> bound to organic matter >bound to Fe-Mn oxides>exchangeable form>bound to carbonate. After the treatment of the lower dose, middle dose and higher dose, the fractionation distribution of Pb showed a trend in the order: residue>bound to Fe-Mn oxides> bound to organic matter> bound to carbonate>exchangeable form. After the high dose treatment, the fractionation distribution changed to the order: bound to Fe-Mn oxides>bound to carbonate>residue>bound to organic matter>exchangeable form. For Cd salt, after the injection of low dose and lower dose the distribution showed a trend in the order: residue>bound to Fe-Mn oxides>exchangeable form> bound to organic matter>bound to carbonate, However, for the other doses, the forms of distribution showed no regular change. For the Zn salt, the order of fractionation distribution was always residue>bound to Fe-Mn oxides>bound to organic matter>bound to carbonate>exchangeable form after different doses treatment.