不同钝化材料对农田土壤中砷的钝化效果研究

笔者探究不同添加比例钝化材料对贵州喀斯特岩溶地区农田土壤中有效态As钝化特征,旨在为砷污染土壤修复提供参考。试验通过向砷污染土壤中分别添加生石灰等12种不同比例钝化剂,分析不同钝化剂对土壤pH、有效As和钝化率的影响。6种无机钝化材料中铁矿粉、钢渣和煤渣均能有效降低农田土壤中As有效态含量,以施用煤渣效果最佳,使土壤pH降低0.01~0.16个单位,不同添加量的钝化率为34.58%~56.33%;6种有机钝化材料中添加腐殖质的土壤中As有效态含量呈现先升高后降低的趋势,土壤pH变化不显著,不同添加量的钝化率为40.96%~44.08%。铁矿粉、钢渣、煤渣和腐殖质能稳定土壤中As的活性。考虑到材料投入成本,钢渣、煤渣更适合广泛应用于重金属污染土壤修复。

Effect of Different Passivation Materials on Arsenic in Farmland Soil

Different ratios of passivation materials were added to the arsenic contaminated farmland soil in Karst area of Guizhou to evaluate their effectiveness of immobilizing arsenic, aiming to provide references for the remediation of contaminated farmland soil. The effects of passivation agents on soil pH, effective As and passivation rate were analyzed by adding 12 passivation agents of different proportions. Iron ore powder, steel slag and coal cinder in the 6 inorganic passivation materials could effectively reduce the content of effective state As in the farmland soil. Applying coal cinder had the best effect and could reduce the soil pH by 0.01-0.16 units. The passivation rate of different additions was 34.58%-56.33%. Among the 6 organic materials, the content of As in the soil with humus increased first and then decreased, and the soil pH did not change significantly. The passivation rate of different additions reached 40.96%-44.08%. Thus, iron ore powder, steel slag, coal slag and humus could reduce the soil pH and stabilize the bioavailability of As in the farmland soil, considering the material input cost, steel slag and coal slag are more suitable for remediation of heavy metal contaminated farmland soil.