硅硫材料对复合污染土壤镉砷赋存形态的影响

Effects of silicon-and sulfur-containing materials on the dynamics of cadmium and arsenic species in compound polluted soil

为探究含硅含硫材料对极重度(矿区)镉砷复合污染土壤镉、砷形态动态变化的影响,以及轻、重度镉砷复合污染耕地土壤与淹水条件下含硅含硫材料对土壤镉、砷形态变化的影响,本试验采集三种不同污染程度土壤(极重度矿区污染土壤、重度污染耕地土壤、轻度污染耕地土壤),通过室内土壤培养的方法模拟施用含硅含硫材料,研究单一施用(G、S)、混合施用(G S)和混合施用结合淹水处理(G SI)对轻、重度耕地土壤镉砷赋存形态的影响,单一施用(G 1、G2、S1、S2)、混合施用(G S1、GS2)以及不同施用浓度处理对极重度矿区污染土壤镉砷赋存形态的影响。结果表明:含硅、含硫材料均能降低矿区镉砷复合污染土壤中弱酸可溶态镉含量,降低幅度为6.42%~13.46%,残渣态含量上升幅度为89.84%~248.57%,显著降低土壤中镉的有效性,其中施用量高的含硅含硫材料处理(G S2)效果最为明显。硅硫材料各处理使土壤中残渣态砷上升了4.74%~13.98%,降低了土壤中砷的有效性,其中施用量低的含硅含硫材料处理(G S1)效果最为明显。硅硫材料对轻、重度污染土壤中弱酸可溶态镉含量均有降低,降低幅度为10.14%~29.93%,残渣态含量上升幅度为21.89%~60.8%,所有处理中含硅含硫材料结合淹水处理(G SI)效果最好,但砷在淹水处理下反而使残渣态分别下降了16.51%~23.96%。含硅含硫材料可降低三种类型土壤镉、砷生物有效性,含硅含硫材料混合处理优于单一处理,耕地土壤GSI处理降低土壤镉砷有效性效果最好。

Dynamic changes in cadmium and arsenic species in soils polluted by silicon-and sulfur-containing materials under extremely severe cadmium and arsenic contamination(such as in mines)were investigated.This experiment collected three kinds of soils with differ⁃ent pollution levels(extremely severely polluted soils,severely polluted soils,and mildly polluted soils).The indoor soil cultivation method was used to simulate the application of silicon and sulfur-containing materials to research the effect of the single application(G,S)and mixed application(GS)and mixed application combined with flooding treatment(GSI)on cadmium and arsenic occurrence patterns in light and severe farmland soils.And also the experiment studied the effect of single application(G1,G2,S1,S2),mixed application(GS1,GS2)and different application concentration treatments on the cadmium and arsenic occurrence forms in the polluted soils of extremely severe mining areas.The results showed that the content of weak acid soluble cadmium in the cadmium-arsenic compound contaminated soil in the mining area could be reduced by 6.42%~13.46%,and the residual content was 89.84%~248.57%.The effectiveness of cadmium in the soil was significantly reduced,indicating that the application of high contents of silicon-and sulfur-containing materials(GS2)was effective.The treatment increased the residual arsenic in the soil by 4.74%~13.98%,reducing its availability;treatment with the silicon-and sulfurcontaining materials at low application rate(GS1)was the most obvious.The content of weak acid soluble cadmium in the mildly and heavi⁃ly polluted soils of arable land decreased in the range of 10.14%~29.93%,and the residual content increased by 21.89%~60.8%.Com⁃bined with flooding treatment(GSI),the effect was the best;arsenic in the residual state decreased by 16.51%~23.96%.Under the flooding treatment alone,residual arsenic decreased by 16.51%~23.96%.Silicon-and sulfur-containing materials reduced the bioavailability of cadmium and arsenic in the three types of soils studied.The treatment soils with a mixture of silicon-and sulfur-containing materials was better than treatment with individual materials.The GSI treatment on soil cadmium and arsenic showed the best performance.