硅酸钾及其与锰硫配施防控水稻复合重金属污染的效果

由于不同重金属的土壤化学性质迥异，同步钝化土壤复合重金属成为土壤污染修复亟待解决的瓶颈问题. 采用土壤盆栽试验，以自然Cd、Pb、Cu、As复合污染土壤为研究材料，设置空白对照(CK)和调理剂对照(石灰石)两个对照，研究了3种硅基调理剂〔(硅酸钾、锰-硅酸钾(氯化锰10%+硅酸钾90%)、硫-硅酸钾(硫氢化钠2.5%配施+硅酸钾97.5%)〕对土壤重金属形态转化，水稻吸收Cd、Pb、Cu、As和养分元素，以及水稻生长和抗氧化胁迫反应的影响. 结果表明:3种硅基土壤调理剂的降Cd效果均显著高于调理剂对照(石灰石). 与空白对照(CK)相比，硅酸钾、锰-硅酸钾和硫-硅酸钾3种硅基调理剂糙米Cd含量分别显著(P<0.05)降低30.0%、45.5%和35.7%，糙米Pb含量分别显著(P<0.05)降低56.6%、62.6%和37.1%，其中锰-硅酸钾配施降Cd、降Pb效果最佳，但3种调理剂降Cu和降As效果不显著. 各调理剂均能促进水稻的生长、养分吸收和抗氧化能力，提高土壤pH，降低土壤可交换态Cd、Pb比例. 研究显示，硅酸钾及与锰、硫配施均能显著降低糙米中的Cd、Pb含量并促进作物生长，可用于水稻Cd、Pb复合污染防控. 

Control Effects of Combined Heavy Metal Pollution in Rice by Using Silicate and Its Mixing of Mn/S

Different heavy metals have different soil chemical properties. Simultaneous treatment of the different heavy metals in the soil has become a bottleneck problem to be solved in soil pollution remediation. The natural Cd, Pb, Cu, As compound polluted soil was used as the research material, CK (blank) and limestone (conditioner control) were used as two controls, and soil pot experiments were performed to explore the effects of three silicon-based conditioners (potassium silicate, manganese-potassium silicate (manganese chloride 10% + potassium silicate 90%), sulfur-potassium silicate (sodium hydrosulfide 2.5% + potassium silicate 97.5%)) on the transformation of heavy metals in soil, the accumulation of Cd, Pb, Cu, As and nutrient elements in rice, and the rice growth and antioxidant stress response. The results showed that all the three silicon-based conditioners had significantly higher Cd-reducing capability than the conditioner control (limestone). Compared with CK, the three Si-containing passivators reduced the content of Cd and Pb in brown rice by 30.0%, 45.5%, 35.7% and 56.6%, 62.6%, 37.1%, respectively, and manganese-potassium silicate had the best effect. However, none of the passivators significantly reduced Cu and As in rice. Each conditioner could promote rice nutrient absorption and antioxidant capability, increase soil pH, and reduce the proportion of exchangeable Cd and Pb in soil. In conclusion, the application of silicate and its Mn and S modified mixture significantly reduces the content of Cd and Pb in brown rice, which can be used for the remediation of rice Cd/Pb compound pollution.