【摘要】 采用温室盆栽实验,研究了模拟酸雨条件下铁硅材料、鸡粪及其高温裂解生物炭单施或复配对土壤Cd、As形态及生物有效性的影响。结果表明:酸雨导致土壤p H值显著降低,并提高土壤有效态Cd、As含量,几种钝化剂的添加能提高土壤p H值0.41~1.34个单位,铁硅材料与生物炭组合能显著降低土壤Cd、As有效态含量。酸雨对蔬菜的生长有显著抑制作用,并促进重金属在蔬菜体内积累,且显著增加铁硅材料和生物炭单一处理蔬菜对Cd、As的吸收,而铁硅材料与生物炭复合处理可以有效抵御酸雨的不良影响。土壤重金属的化学形态分析显示,酸雨处理显著提高土壤中水溶交换态Cd(1 mol·L-1Mg Cl2提取)比例,降低有机硫化物态和残渣态Cd比例。铁硅材料与生物炭复合处理(IS+BC700)土壤中水溶交换态Cd显著降低,土壤中Cd形态主要向铁-锰氧化物结合态和有机硫化物结合态转化且土壤中残渣态Cd比例升高,从而显著降低其生物有效性。IS+BC350组合处理显著降低土壤中非专性吸附态As比例。本研究表明铁硅材料与生物炭的组合可以有效缓解酸化条件下镉砷复合污染农田土壤重金属对作物的毒害作用。更多还原

【Abstract】 A greenhouse pot experiment was conducted to study the effects of individual or combined treatments of iron-silicon material(IS), chicken manure(CM)and its biochar pyrolyzed at 350 ℃(B350)and 700 ℃(B700)on the soil Cd and As speciation and vegetableuptake under simulated acid rain condition. The results showed that the simulated acid rain led to a significant decrease in soil p H and in-crease in bioavailable Cd and As content in soil. The addition of amendments increased soil p H of 0.41~1.34 unit. Combined treatments ofIS and biochar decreased soil bioavailable Cd and As contents significantly. The simulated acid rain significantly inhibited the growth of veg-etable and promoted the accumulation of As and Cd in the edible parts of the vegetable. The simulated acid rain also caused adverse effecton the remediation of individual IS, CM and biochar, while combined treatments of IS and biochar could effectively resist the adverse effect of acid rain. Chemical speciation analysis of heavy metals in soil showed that acid rain treatment significantly increased the water solubleand exchangeable Cd, reduced the organic-bound/sulfide Cd and residual Cd. With the addition of combined treatment of IS and BC700,the soil water soluble and exchangeable Cd decreased significantly, while the iron-manganese oxide-bound, organic sulfide-bound Cd andthe residual Cd increased, resulting in a significant decrease in Cd bioavailability. Combined treatment of IS and BC350 can significantly re-duce the proportion of non-specifically adsorbed As in soil. The combined treatments of iron-silicon and biochar can effectively mitigatethe toxic effects of As and Cd in farmland soils under acid rain or acidified conditions.更多还原