磷肥种类对重金属污染土壤修复效果研究

Study on remediation effect of phosphate fertilizer types on heavy metal contaminated soil

磷肥对被重金属污染的土壤有着一定的修复能力,但不同类型的磷肥由于其含量、成分的不同,对于重金属污染土的修复能力也不尽相同。本文以某地被污染的重金属稻田土为研究对象,借助土培试验以及淋溶试验,评价两种磷肥对重金属污染土壤地修复效果,结果发现:钙镁磷肥与磷酸二氢钾对于不同重金属污染的土壤修复效果不相同,大致表现为,磷酸二氢钾对Pb、Cd含量较高的土壤钝化效果较好,能够显著降低土中的Pb、Cd含量,但对于含Cu、Zn的土壤修复效果不尽人意,用量过多反而会造成上述两种重金属活化的现象。且磷酸二氢钾其对Pb、Cd含量较高的土壤钝化效果好于钙镁磷肥,其原因在于作为水溶性磷肥,磷酸二氢钾更易溶于水,能在土壤中电离更多的磷酸根离子,进而能更快地与土壤中的重金属发生钝化反应,但同样由于此原因,导致其容易更快地渗入地下并积累,容易流失并造成地下水地污染,从而会导致过量地施肥造成Cu、Zn重金属活化。因此选择合适的磷肥种类对重金属污染土壤的修复能力有着事半功倍的效果。

Phosphate fertilizers have a certain ability to repair heavy metal-contaminated soils,but different types of phosphate fertilizers have different repair capabilities for heavy metal-contaminated soils due to their different contents and components.In this paper,taking the heavy metal paddy soil in a polluted area as the research object,with the help of soil culture test and leaching test,the remediation effect of two phosphate fertilizers on heavy metal contaminated soil was evaluated.The soil remediation effect is not the same as the soil remediation effect of different,roughly shown,potassium dihydrogen phosphate has better passivation effect on soil with high content of Pb and Cd,and can significantly reduce the content of Pb and Cd in soil,but for soil remediation containing Cu and Zn The effect is unsatisfactory,and too much dosage will cause the above two heavy metals to activate.And potassium dihydrogen phosphate has a better passivation effect on soils with higher Pb and Cd content than calcium magnesium phosphate fertilizer.The reason is that as a water-soluble phosphate fertilizer,potassium dihydrogen phosphate is more soluble in water and can ionize more phosphoric acid in soil.Root ions can passivate more quickly with heavy metals in the soil,but also for this reason,it is easy to infiltrate into the ground more quickly and accumulate,and it is easy to run off and cause groundwater pollution,which will lead to excessive fertilization.Cu,Zn heavy metal activation.Therefore,choosing the appropriate type of phosphate fertilizer has a multiplier effect on the remediation ability of heavy metal-contaminated soil.