几种典型纳米材料对土壤-植物体系中砷镉积累的阻控效应

Alleviation of arsenic and cadmium accumulation in soil-plant system by typical nanomaterials

纳米材料(NPs)已成为近年来农业领域对污染控制具有较好前景的新兴技术.本研究针对农田蔬菜中砷(As)和镉(Cd)复合污染问题,比较了4种代表性NPs(ZnO、CeO_(2)、SiO_(2)、S)在As/Cd单一和复合污染场景下对小白菜中重金属的富集和毒性效应的抑制效应和机制.结果表明,在Cd环境中,ZnO NPs通过提高土壤pH和Zn2+抑制了植物对Cd的吸收;在As环境中,溶解性有机碳增加导致孔隙水和植物体中As含量下降.此外,ZnO NPs还可以显著促进植物生长,增强地上部SOD、POD抗氧化酶活性,降低MDA水平,提高了植物对重金属的抗性.CeO_(2) NPs同样可以促进植物生长,降低了根部MDA水平,但对植物对As和Cd吸收的抑制能力程度不如ZnO NPs,主要降低了植物根中金属的积累量.SiO_(2) NPs虽然一定程度上抑制了植物根对Cd的吸收,但显著促进了复合污染中地上部分As累积.而S NPs导致土壤明显酸化,抑制了植物地上部的生长,并导致小白菜根中Cd含量显著升高.综合来看,ZnO和CeO_(2)具有较好的阻控效果,SiO_(2)和S纳米材料则需要谨慎使用,结果可以为As-Cd复合污染提供“因土配方”的纳米技术参考.

Nanoparticles(NPs)have emerged as a promising technology for pollution control in agriculture in recent years.This study investigates the mitigation effects and mechanisms of four typical NPs(ZnO,CeO_(2),SiO_(2),and S)on arsenic(As)and cadmium(Cd)accumulation and toxicity in Chinese cabbage under single and combined As/Cd pollution scenarios.The results showed that in Cd-contaminated soil,ZnO NPs effectively reduced plant Cd uptake by elevating soil pH and sequestering Zn2+.Conversely,in As contaminated soil,the increase of dissolved organic carbon led to a decline in both pore water and plant As concentrations.Additionally,ZnO NPs promoted significant plant growth and enhanced the antioxidative enzyme activities of superoxide dismutase(SOD)and peroxidase(POD)in shoot tissues.This is accompanied by a reduction in malondialdehyde(MDA)levels,ultimately enhancing the plants’resistance to heavy metal stressors.Similarly,CeO_(2) NPs promoted plant growth and decreased root MDA levels;however,their ability on inhibition metal uptake is not as pronounced as that of ZnO NPs,primarily reducing the accumulation of metals in plant roots.While SiO_(2) NPs partially inhibited plant root-Cd,they notably promoted the shoot-As in co-contaminated scenarios.Conversely,S NPs induced significant soil acidification,suppressed plant growth,and significantly increased Cd concentration within Chinese cabbage roots.Overall,ZnO and CeO_(2) demonstrate superior mitigation efficacy,while caution is needed in the application of SiO_(2) and S nanomaterials.These findings offer valuable insights into nano-engineering strategies tailored to“soil-adapted”solutions for As-Cd co-contamination.