Agro-Environmental Protection Institute, Ministry of Agriculture of China, Tianjin, 300191, China.
Environ Sci Process Impacts. 2020 Apr 29;22(4):1045-1056. doi: 10.1039/c9em00570f.
Arsenic exists ubiquitously in the soil and has been proved to be of significant hazard to human health upon transmission through food chain. Herein, we determined the effects of Fe-Mn-La ternary oxide-biochar composites (FMLBCs) on arsenic (As) fractionation, soil enzyme activities, and microbial communities in arsenic-polluted soils. The results demonstrated that the proportion of non-swappable As fractions reduced and that of the exchangeable As fractions increased with the addition of FMLBCs. Furthermore, the addition of FMLBCs significantly increased the catalase (CAT) activity (P < 0.05), and an increase of 69.2-268% was observed when 2 wt% FMLBCs were added. Supplementation with biochar or FMLBCs increased the relative abundance of Proteobacteria and Acidobacteria and decreased the relative abundance of Firmicutes; moreover, the effect was more obvious as the addition amount of biochar or FMLBCs increased. In addition, the FMLBCs, except for FMLBC3, increased the content of available phosphorus. Moreover, amendments of FMLBCs led to an increase in the available potassium content by an average of 212%, 113%, and 62.1% in highly polluted soil. Therefore, the FMLBCs affected the physical and chemical properties of soil in different manners. The results suggested that the addition of FMLBCs changed the distribution and increased the immobilization of As in the soil; this could indirectly reduce the risk of the transport of As to rice. The amendment mechanism of FMLBCs may include changes to the physicochemical soil properties and consequently, the soil enzyme activities are affected, which can influence the microbial communities in soils.
砷在土壤中普遍存在，通过食物链传递已被证明对人类健康有重大危害。在此，我们研究了铁锰镧三元氧化物-生物炭复合材料（FMLBCs）对砷污染土壤中砷形态、土壤酶活性和微生物群落的影响。结果表明，随着 FMLBCs 的添加，非交换态砷的比例减少，可交换态砷的比例增加。此外，FMLBCs 的添加显著提高了过氧化氢酶（CAT）活性（P<0.05），当添加 2wt% FMLBCs 时，CAT 活性增加了 69.2-268%。生物炭或 FMLBCs 的添加增加了变形菌门和酸杆菌门的相对丰度，降低了厚壁菌门的相对丰度；而且，随着生物炭或 FMLBCs 添加量的增加，这种效果更加明显。此外，除了 FMLBC3，FMLBCs 还增加了有效磷的含量。此外，FMLBCs 的添加使高污染土壤中有效钾的含量平均增加了 212%、113%和 62.1%。因此，FMLBCs 以不同的方式影响土壤的物理和化学性质。研究结果表明，FMLBCs 的添加改变了砷在土壤中的分布并增加了砷的固定化，这可以间接降低砷向水稻迁移的风险。FMLBCs 的改良机制可能包括改变土壤的理化性质，从而影响土壤酶活性，进而影响土壤中的微生物群落。
