石灰用量对污染红壤和黄泥土中有效态铜锌含量的影响

采用外源加入重金属铜锌硝酸盐的方法,制成铜、锌单一及复合污染的三级污染红壤和黄泥土（Cu 200mg/kg、Zn 400 mg/kg）,稳定一个月,施入低（0.50 g/kg）、中（1.50 g/kg）和高（2.50 g/kg）3种不同用量的石灰,稳定两个月后测定土壤有效态铜、锌含量和pH值,以阐明石灰用量对不同污染土壤中重金属有效态含量的影响。结果表明,随石灰用量的增加,复合污染红壤中有效态铜含量较对照依次降低31%、76%和87%;而石灰用量对黄泥土中有效态铜影响的差异不显著;两种土壤中有效态锌含量均随石灰用量的增加而显著减少;复合污染较单一污染相比,有效态铜及有效态锌的含量差异不显著。在复合污染下,低、中量石灰使黄泥土中有效态铜含量较红壤减少89%和63%,有效态锌减少27%和65%。但加入高量石灰,两种土壤差异不显著。石灰能够降低单一与复合污染铜、锌有效态的含量,但其效果因土壤类型而异,在红壤上选择施用高量石灰而在黄泥土上则适宜施用低中量石灰,以取得最佳的修复效果和效益。

Effects of lime application rate on available copper and zinc content in single and complex polluted red and paddy soils

The effects of lime amendment rate on heavy metals polluted 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 red and paddy soils, respectively and together. Three application rates of lime were added to the soils after incubated for one month. Then they were incubated for two months subsequently. The available Cu/Zn content and pH were determined at the end of the incubation. Results showed that, compared with the control, the available Cu content in complex polluted red soil was significantly decreased by 31%, 76% and 87% for the lime application of 0.5, 1.5 and 2.5 g/kg, respectively. However, there was no significant difference for available Cu in paddy soil. The available Zn content in both the red and paddy soils significantly decreased with increasing application rate of lime. For the both soils, there was no significant difference for available Cu or Zn in complex polluted soil comparing to the single polluted one. The available Cu and Zn content in complex polluted paddy soil was significantly lower than that in red soil with low and mid lime application rates. It was showed that available Cu content in paddy soil was 89% and 63% less than that in red soil, and available Zn content was less by 27% and 65%, respectively. However, there was no significant difference with high application rate between the two soils. It was concluded that lime application could significantly decrease available Cu and Zn content in single and complex polluted soils. The effects of lime amendment varied between the types of soil. It is suggested that high application rate was good for polluted red soil, and low or middle for paddy soil to get the best amendment effects and efficiency.