绿化植物废弃物对土壤中Cu Zn Pb和Cd形态的影响

利用自制的Cu、Zn、Pb和Cd污染的灰潮土和黄泥土,通过室内培养实验研究了不同绿化植物废弃物添加量和不同培养时间对这两种污染土壤中这4种重金属形态的影响。结果表明,绿化植物废弃物的加入抑制了Cu的活化,且添加60%绿化植物废弃物时有机结合态Cu的含量最高;绿化植物废弃物与污染土培养2～3个月时,残余态Zn的含量最高,对植物的毒害最小;绿化植物废弃物添加量为60%时灰潮土中有效态Pb含量较低,而添加量为30%时黄泥土中有效态Pb含量最低;绿化植物废弃物添加量的多少对灰潮土Cd形态的影响较小,但黄泥土中的Cd则随绿化植物废弃物量的增加活性逐渐减弱,且两种土壤均在培养2～3个月时可交换态Cd的含量最低。

Effect of Greenery Waste Incorporation on the Speciation of Cu, Zn, Pb and Cd in the Soils

The transformation of the speciation of Cu, Zn, Pb and Cd in Calcareous Chao Soil and Yellow Clay Soil was studied with incubation experiments. The results showed that the available type of Cu was decreased when the soils incubated with greenery waste, and the content of organic-Cu complexes increased with the increase in greenery waste added and reached the maximum value at the greenery waste/soil mass ratio of 3/2. The soils had the highest content of residual Zn after incubation with greenery waste incorporated for 2 to 3 months, which suggested that the toxicity of Zn to plants was the smallest under this condition. The lowest availability of Pb was observed at the greenery waste/soil mass ratio of 3/2 for the Calcareous Chao Soil and the greenery waste/soil mass ratio of 3/7 for the Yellow Clay Soil. The incorporation of greenery waste had an unconspicuous effect on Cd speciation in the Calcareous Chao Soil. However, Cd activity in the Yellow Clay Soil decreased with the increase in greenery waste added, and the two soils had the lowest content of exchangeable Cd after incubated with greenery waste for 2 to 3 months.