中轻度污染菜地土壤中重金属阻控剂组合优化研究

Optimization of Combined Retarding Agent Amendments for Controlling Heavy Metal Pollution in Moderately Contaminated Vegetable Farmland

为了解阻控剂组合及单一因素对中轻度污染菜地土壤重金属迁移释放的影响,采用模拟培养及L16（44＋32）正交试验法对土壤中重金属阻控剂及其配方参数进行优化,以期筛选出最优阻控剂组合配方.研究结果表明：各阻控剂处理组合对污染土壤Pb、Cu、Zn、Cd阻控效果较好,其对Pb、Cu的阻控效果优于对Zn、Cd的阻控效果.单一影响因素分析表明：硅肥对土壤中Pb和Cu、骨炭对土壤中Cu、羟基磷灰石对土壤中Zn和Cd分别具有较好阻控作用,且在适当延长阻控时间和提高温度下添加中、高水平的阻控剂有利于提高阻控效果;与土壤pH相比,土壤类型对重金属阻控效果的影响相对更大.综合考虑各处理组合对菜地土壤中Cu、Zn、Pb、Cd的阻控效应及影响因素,对中轻度Cu、Zn、Pb、Cd污染土壤的复合阻控剂最优配方参数为：pH 4.5~7.5下施用硅肥2.0~8.0g/Kg、羟基磷灰石6.0~8.0g/Kg及骨炭20.0~40.0g/Kg后于15~35℃下培养8~16d;且较之潮土性菜园土壤,在红壤性菜园土壤中各阻控剂可以就低选择用量.

An experiment was conducted through simulated culture and L16 （44 --32） orthogonal tests aiming to study the effects of combined retarding agent and single factor for controlling Cu, Zn, Pb and Cd pollution in vegetable farmland. The results showed that each combined retarding agent could stabilize Cu, Zn,Pb and Cd in contaminated soil, among which the stabilization effect on Pb and Cu was much better than that of Zn and Cd. The influence of single factor analysis showed that silicon fertilizer had the best controlling effect on Pb and Cu pollution, and bone char had the greatest Cu reduction influence, while hydroxylapatite had the greatest Zn and Cd reduction effect, respectively. Furthermore, extending time and raising temperature could effectively improve the controlling effect of middle and high level combined retarding agent, moreover, soil types affected much more on the heavy metal retardance compared with pH. Comprehensively considering the effect of each combined retarding agent and its factors for Cu, Zn, Pb and Cd controlling in vegetable farmland, it was clear that the optimized parameters to stabilize heavy metal in moderately contaminated vegetable farmland soil was as followed, under the condition of pH 4.5-7.5, with application dosage of silicon fertilizer being 2.0-8.0 g/kg, hydroxylapatite being 2.0-8.0 g/kg and bone char being 20-40 g/kg, then being cultivated for 8-16 d under 15-35 ℃, moreover, much lower dosage of each combined retarding agent could be added into red vegetable farmland originated from red soil other than aqualf soil.