【作者】 金美玉；

【导师】 李博文；

【作者基本信息】 河北农业大学 ， 土壤学， 2007， 硕士

【摘要】 针对土壤Cd、Pb污染的原位固定修复问题，以钠基膨润土、膨润土、沸石、硅藻土等4种矿物材料为试材、潮褐土添加外源水溶性Cd、Pb化合物模拟土壤Cd、Pb污染、蔬菜为指示植物进行了盆栽试验，比较系统地研究了矿物材料修复土壤Cd、Pb污染的规律。主要研究结论如下：1．钠基膨润土、膨润土、沸石和硅藻土均可用于土壤Cd、Pb复合污染的修复，施用量以30—40g·kg^-1为宜，分别可降低油菜Cd、Pb吸收量的15％和25％以上。其中，沸石降低油菜Cd吸收量的潜力最大；硅藻土降低油菜Pb吸收量的效果最佳。2．钠基膨润土、膨润土和沸石主要靠提高土壤阳离子交换量吸附固定土壤Cd、Pb，潜在“二次污染”的危险较大；而硅藻土并不是靠提高土壤阳离子交换量吸附固定土壤Cd、Pb，潜在“二次污染”的危险较小，可作为土壤Cd、Pb污染原位固定修复的优选矿物。3．膨润土、沸石和硅藻土可通过提高土壤pH降低土壤Cd、Pb活性，抑制油菜对土壤Cd、Pb的吸收，是这些矿物固定修复土壤Cd、Pb污染的一个重要机制。但钠基膨润土通过提高土壤pH，仅能抑制油菜对土壤Cd的吸收，并不显著抑制对土壤Pb的吸收。4．矿物材料修复土壤Cd、Pb污染的过程中，降低土壤速效N、P含量，抑制土壤Cd、Pb被油菜吸收。硅藻土通过降低土壤速效N、P含量，抑制土壤Cd、Pb被油菜吸收，是它修复土壤Cd、Pb污染的一个重要原因；钠基膨润土通过降低土壤速效N含量，抑制土壤Cd、Pb被油菜吸收；沸石通过降低土壤速效P含量，抑制土壤Cd、Pb被油菜吸收；膨润土不具有这种作用。5．在矿物材料修复土壤Cd、Pb污染的过程中，所用4种矿物材料均产生了土壤Cd促进Pb吸收的Cd—Pb复合效应；并且钠基膨润土还产生了土壤Pb促进Cd吸收的Pb—Cd复合效应。不能仅凭矿物材料对土壤有效态Cd、Pb含量的影响，来评价它们对土壤Cd、Pb复合污染的修复效果。更多还原

【Abstract】 Effects of in situ immobilization by applying 4 mineral materials were deeply studiedto remedy Cd-Pb contaminated soil. Experiment of the in situ immobilization was carriedout by means of pot experiment with rape as indicator plant. Na-modified bentonite,bentonite, zeolite and diatomite were used in the experiment as studied mineral materials.Cd-Pb contaminated soil was stimulated by adding water-soluble Cd and Pb compoundreagent. Results of the experiment were summarized as follows:1. Na-modified bentonite, bentonite, zeolite and diatomite can be used to remedyCd-Pb contaminated soil as amendments of the in situ immobilization. Suitable contents ofadded these mineral materials are 30—40g·kg^-1 and able respectively to decrease over 15%and 25% of Cd and Pb contents absorbed by rape, in which zeolite is one of the mostpotential to decrease Cd contents absorbed by rape. Diatomite is one of the most effectivein situ immobilization in the mineral materials to remedy the soil contaminated with Pb.2. Na-modified bentonite, bentonite and zeolite mainly depend on increasing CEC tofix Cd and Pb in the soil, but diatomite does not. Because Cd and Pb fixed by increasingCEC may be released to solution of the soil again and become available Cd and Pb,potentiality of their resulting in contamination again is much more than diatomite.Diatomite has priority to in situ immobilization of remedying Cd-Pb contarninated soil.3. It is an important form of in situ immobilization that bentonite, zeolite and diatomitedecrease bioavailability of Cd and Pb to inhibit rape absorbing these metals by increasingpH in the Cd-Pb contaminated soil. Na-modified bentonite is just able to inhibit rapeabsorbing Cd but Pb by means of increasing pH in the soil.4. Bioavailability of Cd and Pb can be decreased by decreasing contents of rapidlyavailable N and P in the soil for the mineral materials to remedy Cd-Pb contaminated soil.It is an important factor that diatomite is able to decrease contents of rapidly available Nand P in the soil, which results in inhibiting rape to uptake Cd and Pb to remedy the soiltogether. Meanwhile, inhibiting rape to uptake Cd and Pb results from Na-modifiedbentonite’s decreasing contents of rapidly available N and zeolite’s decreasing contents ofrapidly available P in the soil. The effect of bentonite does not come into being in this way.5. Applying the 4 mineral materials to remedy the Cd-Pb contaminated soil, thesemineral materials respectively result in Cd-Pb interaction which Cd promote Pb to beabsorbed in the soil, and Na-modified bentonite else result in Cd-Pb interaction which Pbpromote Cd to be absorbed in the soil. Therefore, It is difficulty to indicate the effectiveness of remedying the Cd-Pb contaminated soil that single content of available Cdor Pb in the soil are used as an indicator to assess effects of in situ immobilization byapplying the mineral materials.更多还原