磷酸盐和石灰对污染红壤与黄泥土中重金属铜锌的钝化作用

Effects of phosphate and lime on passivating of Cu and Zn in single and combined contaminated red and paddy soils

采用外源加入重金属铜锌硝酸盐的方法，制成铜、锌单一及复合的三级污染红壤和数泥土（Cu200mg·kg^-1、Zn400mg·kg^-1），平衡2个月；分别施人磷酸盐、石灰，稳定4个月后测定土壤中有效态铜、锌的含量，以阐明磷酸盐和石灰对重金属污染土壤中铜锌的钝化作用。结果表明，施入磷酸盐稳定120d后，两种土壤中有效锌含量都显著降低，红壤中有效铜含量降低了8.3％～11．6％，而黄泥土中有效铜含量变化不明显；施入石灰后，红壤中铜锌有效性含盛降低了87．6％～92．3％，黄泥土中有效锌含量降低了90％，而有效铜含量最大降低幅度为47．4％。由此可见，磷酸盐对红壤中铜锌的钝化作用较强，对黄泥土中铜的钝化作用弱；石灰对两种土壤中铜锌的钝化作用都很强；磷酸盐和石灰对单一污染土壤铜锌的钝化固定作用要强于复合污染。

Effects of phosphate and lime on passivating of heavy metals in contaminated red and paddy soils were studied by incubation experiment. It was simulated for the third national standardization of copper and zinc polluted soils by adding copper and zinc nitrate into the soils, respectively and together. Phosphate and lime were applied to the soils after incubated for two months, and then they were incubated for four months subsequently. The available Cu/Zn content was determined at the cad of the incubation. Results showed that, compared with the control, phosphate could significantly decrease the available Zn content on single and combined polluted red and paddy soils after balance 120 days. Application of phosphate could significantly decrease the available Cu content from 8.3% to 11.6% on single and combined polluted red soil. However, this effect wasn＇t significantly on polluted paddy soil. As for application of lime, it could decrease the available Cu/Zn content in both red and paddy soils significantly. The available Cu/Zn content in red soil decreased from 87.6% to 92.3%. The available Zn content in paddy soil decreased 90% in average, and the maximum decreasing of the available Cu content in paddy soil was only 47.4%. It was suggest that phosphate could reduce the availability of Cu/Zn in red soil significantly, but the effect was not significant for Cu in paddy soil. Application of lime could reduce availability of Cu/Zn in both two soils effectively. The influences of phosphate and lime on passivating of Cu and Zn were greater on single than that of combined metals polluted soils.