铁锰双金属材料对As和重金属复合污染土壤钝化修复及其生态效应的影响

通过室内模拟培养实验,研究了铁锰双金属材料(FMBO)对3种As和重金属复合污染土壤钝化修复及其生态效应的影响。结果表明,在0%~5%范围内,随着FMBO添加量的增加,污染土壤中As和重金属的有效态含量逐渐降低,相比于对照,在5%添加量条件下,As、Pb、Cd、Zn和Cu的有效态浓度分别下降了93.7%~100%、30.8%~57.8%、81.3%~95.0%、66.7%~95.3%、55.8%~100%。由种子发芽实验结果可知,当FMBO添加量≤2.5%时,FMBO能够对污染土壤中植物的生长发育起到减毒作用;在添加量为2.5%时,污染土壤浸出液培养的小麦种子生长情况最优,种子发芽率、根长和株高能分别达到86%~92%、7.25~9.09 cm和8.62~9.91cm;而当FMBO添加量达到5%时,其对种子的萌发及生长产生抑制作用。由土壤微生物多样性分析结果可知,FMBO材料会使土壤微生物的香农-威纳多样性指数降低,群落组成发生变化。因此,在重金属污染土壤钝化修复前,需要从钝化效果和生态效应影响两方面进行考虑,确定修复材料的最佳添加量。

Stabilization effects and ecological impacts on As and heavy metal co-contaminated soils stabilized by Fe-Mn binary oxides

In this article, laboratory culture experiments were carried out to investigate the stabilization effects and ecological impacts on three As and heavy metal co-contaminated soils stabilized by Fe-Mn binary oxides(FMBO). In the extraction experiments, the results showed that FMBO could reduce the concentration of available As and heavy metals in the soils, which could decrease 93.7%~100%, 30.8%~57.8%,81.3%~95.0%,66.7%~95.3%,55.8%~100% of available As, Pb, Cd, Zn, Cu after adding FMBO under 5% mass percentage dosage. In the seed germination experiments, the results showed that under 0%~2.5% mass percentage dosage, FMBO could reduce the toxic effects of As and heavy metals on the growth and development of plants in the soils.Under 2.5% mass percentage dosage, the seed germination rate, root length, seedling length could reach 86%~92%, 7.25~9.09 cm, 8.62~9.91 cm respectively, which were the best of all treatments. But when the FMBO addition reached 5%, it could inhabit the germination and growth of the wheat seeds due to Mn²⁺ releasing. In addition, FMBO could reduce the soil microbial diversity slightly and change the microbial community composition of the three contaminated soils. In conclusion, stabilization effectiveness and ecological impacts should be considered simultaneously before field trials to determine the optimal addition of the remediation materials.