4种复合钝化剂对水稻重金属镉吸收的影响

Effects of Four Amendments on Heavy Metal Cadmium Pollution in Rice Fields

【目的】不同钝化剂材料组合以及钝化剂的使用含量对土壤重金属和水稻籽粒Cd含量的影响,初步讨论其钝化机理以及对土壤理化性质的影响,为复合钝化剂的土壤重金属修复和对土壤环境的影响提供理论指导和依据。【方法】选用活性氧化镁、钙矿粉、蒙脱石、硅藻土等的天然矿粉化合物,采用多种配比和不同剂量在水稻田中开展试验,探究4种复合钝化剂对水稻籽粒和土壤中镉Cd含量的影响。【结果】钝化剂的施用提高了土壤的pH值,显著降低了水稻籽粒和土壤中Cd的含量。将其和空白对照相比,施用4种复合钝化剂(S、JL、LA、SW)使水稻籽粒Cd含量降低了9.52%~82.9%,SW-3和LA-2(蒙脱石、硅藻土、高剂量添加)对水稻籽粒Cd的降低能力位于4种钝化剂中首位,JL-1(二氧化硅、硫酸亚铁、氧化铝的天然矿粉混合物)次之。4种钝化剂对土壤Cd钝化效果为7.27%~48.2%,JL-2对土壤Cd的降低最为显著,SW-3次之。施用复合钝化剂对土壤理化性质无显著影响。【结论】研究表明,不同钝化剂复合配比和施用剂量对土壤和水稻籽粒Cd的降低效果存在明显差异,且对土壤肥力有一定程度的增加,添加适量的蒙脱石和硅藻土对修复水稻田Cd污染有较好的效果。

[Objective]The effects of different combinations of passivator materials and the amount of passivators used on soil heavy metals and Cd contents in rice seeds are discussed,and the passivation mechanisms and effects on soil physicochemical properties are also initially discussed so as to provide theoretical guidance and basis for the remediation of soil heavy metals and the impact on the soil environment with a combination of passivators.[Method]Natural mineral compounds of active magnesium oxide,calcium mineral powder,montmorillonite and diatomaceous earth were selected to conduct experiments in rice fields by using various ratios and doses to investigate the effects of four compound passivators on Cd contents in rice seeds and soils.[Result]The application of passivators increased the soil pH and significantly reduced the Cd contents in rice seeds and soil.Comparing them with the blank control,the application of four complex passivators(S,JL,LA,and SW)reduced the Cd contents of rice seeds by 9.52%-82.9%,with SW-3 and LA-2(montmorillonite,diatomaceous earth,and high dose addition)ranking the first among the four passivators in their abilities to reduce Cd in rice seeds,and JL-1(a natural mineral powder mixture of silica,ferrous sulfate,and aluminum oxide)was the second.The effects of the four passivators on soil Cd passivation ranged from 7.27%to 48.2%,with JL-2 having the most significant reduction in soil Cd and SW-3 the second.The application of compound passivators had no significant effect on the physicochemical properties of the soil.[Conclusion]The study showed that there were significant differences in the reduction effects of different passivator compound ratios and application doses on soil and rice seed Cd,and there was a certain degree of increase in soil fertility.Besides,the addition of appropriate amounts of montmorillonite and diatomaceous earth had a better effect on the remediation of Cd pollution in rice fields.