钝化材料复配对土壤Cd生物有效性的影响

Effects of compounds of passivation materials on bioavailability of Cd in soils

为了得到效果好的复配钝化材料,采用正交设计,通过培养实验探讨生物炭、粉煤灰、汉白玉3种钝化材料不同复配方式对土壤pH的影响和对镉(Cd)的钝化效果,从中筛选出6种效果较好的复配方式,并以小白菜为供试植物,通过盆栽实验和大田实验探讨了钝化材料复配对土壤Cd生物有效性的影响。结果表明:3种钝化材料不同复配方式均能显著提高土壤pH,降低土壤有效Cd含量,统计分析发现钝化材料复配过程中对Cd降幅的影响表现为汉白玉>粉煤灰>生物炭。钝化材料添加后,盆栽和大田条件下小白菜可食部位Cd含量均显著降低,综合2种实验条件下小白菜生物量和可食部位Cd含量的变化,1.5%生物炭+1.5%粉煤灰+0.5%汉白玉、1%生物炭+0.5%粉煤灰+1%汉白玉2种复配方式效果最好。

An incubation experiment with orthogonal design was carried out to study the effects of different compounds of the three passivation materials（biochar, fly ash, white marble）on pH and available Cd concentrations of Cd-contaminated soils. Six ideal compounds of the three passivation materials were obtained. Followly, a pot experiment and field experiment were carried out to investigate the effects of the six compounds of the three passivation materials on Cd bioavailability. The different compounds of the three passivation materials increased soil pH and decreased the soil available Cd concentrations significantly. White marble showed the greatest ability to immobilize Cd in soils, followed by fly ash and biochar. Cd concentrations in edible parts of Brassica chinensis L decreased significantly under pot and field experiments. With the evaluation index of plant biomass and Cd concentrations in edible parts of B. chinensis, the combination of 1.5% biochar ＋ 1.5% white marble ＋ 0.5% white marble and 1% biochar ＋0.5% fly ash ＋1% white marble showed the best remediation efficiency.