National Engineering Research Center for Efficient Utilization of Soil and Fertilizer Resources, College of Resources and Environment, Shandong Agricultural University, Daizong Road, Tai'an City, Shandong 271018, PR China.
Observation and Research Station of Land Use Security in the Yellow River Delta, Ministry of Natural Resources (NMR), Shandong Provincial Territorial Spatial Ecological Restoration Center, PR China.
J Hazard Mater. 2024 Sep 15;477:135377. doi: 10.1016/j.jhazmat.2024.135377. Epub 2024 Jul 29.
The excessive accumulation of Cd and Zn in soil poisons crops and threatens food safety. In this study, KMnO-hematite modified biochar (MnFeB) was developed and applied to remediate weakly alkaline Cd-Zn contaminated soil, and the heavy metal immobilization effect, plant growth, and metal ion uptake of foxtail millet were studied. MnFeB application reduced the phytotoxicity of soil heavy metals; bioavailable acid-soluble Cd and Zn were reduced by 57.79% and 35.64%, respectively, whereas stable, non-bioavailable, residual Cd and Zn increased by 96.44% and 32.08%, respectively. The chlorophyll and total protein contents and the superoxide dismutase (SOD)activity were enhanced, whereas proline, malondialdehyde, the HO content, glutathione reductase (GR), ascorbate peroxidase (APX) and catalase (CAT) activities were reduced. Accordingly, the expressions of GR, APX, and CAT were downregulated, whereas the expression of MnSOD was upregulated. In addition, MnFeB promoted the net photosynthetic rate and growth of foxtail millet plants. Furthermore, MnFeB reduced the levels of Cd and Zn in the stems, leaves, and grains, decreased the bioconcentration factor of Cd and Zn in shoots, and weakened the translocation of Cd and Zn from roots to shoots. Precipitation, complexation, oxidation-reduction, ion exchange, and π-π stacking interaction were the main Cd and Zn immobilization mechanisms, and MnFeB reduced the soil bacterial community diversity and the relative abundance of Proteobacteria and Planctomycetota. This study provides a feasible and effective remediation material for Cd- and Zn-contaminated soils.
土壤中过量的 Cd 和 Zn 积累会毒害作物并威胁食品安全。在本研究中，开发并应用了 KMnO-赤铁矿改性生物炭（MnFeB）来修复弱碱性 Cd-Zn 污染土壤，并研究了重金属固定效果、谷子的生长和金属离子吸收。MnFeB 的应用降低了土壤重金属的植物毒性；生物可利用的酸溶性 Cd 和 Zn 分别减少了 57.79%和 35.64%，而稳定的、非生物可利用的残留 Cd 和 Zn 分别增加了 96.44%和 32.08%。叶绿素和总蛋白含量以及超氧化物歧化酶（SOD）活性增强，而脯氨酸、丙二醛、HO 含量、谷胱甘肽还原酶（GR）、抗坏血酸过氧化物酶（APX）和过氧化氢酶（CAT）活性降低。因此，GR、APX 和 CAT 的表达下调，而 MnSOD 的表达上调。此外，MnFeB 促进了谷子植物的净光合速率和生长。此外，MnFeB 降低了茎、叶和谷物中的 Cd 和 Zn 含量，降低了 Cd 和 Zn 在地上部分的生物浓缩系数，减弱了 Cd 和 Zn 从根部向地上部分的转运。沉淀、络合、氧化还原、离子交换和π-π 堆积相互作用是 Cd 和 Zn 固定的主要机制，MnFeB 降低了土壤细菌群落多样性和变形菌门和浮霉菌门的相对丰度。本研究为 Cd 和 Zn 污染土壤提供了一种可行有效的修复材料。
