College of Agriculture and Bioengineering (College of Tree Peony), Heze University, Heze, 274015, China.
Department of Civil and Environmental Engineering, Shantou University, Shantou, 515063, China.
Environ Sci Pollut Res Int. 2021 Sep;28(36):49889-49898. doi: 10.1007/s11356-021-14115-x. Epub 2021 May 4.
As can be volatilized naturally; however, this has adverse environmental effects. In this study, we investigated As volatilization in flooded paddy soil with the addition of biochar (BC) and Fe-Mn-La-modified BC composites (FMLBCs). The addition of BC and FMLBCs caused decreases in total As volatilization in the soil over 7 weeks. Maximum volatilization was achieved in the third week followed by stabilization. Volatilization decreased by 21.9%, 18.8%, 20.8%, and 31.1% with the addition of BC, FMLBC, FMLBC, and FMLBC (BC/Fe/Mn/La weight ratios different), respectively, in lightly contaminated soil, and by 15.2%, 20.5%, 17.6%, and 25.4%, respectively, in highly contaminated soil. The FMLBCs decreased the exchangeable As fractions and increased the non-swappable As in the soil. Furthermore, the addition of FMLBCs significantly reduced the As(III) concentration in a suspended solution (P < 0.05), whereas no significant changes were observed in the As(V) or methyl arsenic acid concentrations. Soil enzyme activity increased and the relative abundances of Proteobacteria and Actinobacteria changed with the addition of FMLBCs. Therefore, the mechanism by which FMLBCs affected As volatilization likely included the following two aspects: (1) FMLBCs affected the transformation and distribution of soil As and decreased As dissolution, crystallization, and methylation; (2) FMLBCs influenced soil properties, which directly affected microorganism activity, thereby affecting As volatilization. FMLBCs therefore can decrease As volatilization properties and be used to control As volatilization in As-contaminated paddy soils.
砷可以自然挥发，但这会对环境产生不利影响。本研究考察了添加生物炭（BC）和 Fe-Mn-La 改性生物炭复合材料（FMLBCs）对淹水稻田中砷挥发的影响。添加 BC 和 FMLBC 导致土壤中总砷挥发在 7 周内减少。第 3 周达到最大挥发量，随后稳定。在轻度污染土壤中，添加 BC、FMLBC、FMLBC 和 FMLBC（BC/Fe/Mn/La 重量比不同）分别使砷挥发减少 21.9%、18.8%、20.8%和 31.1%，在高度污染土壤中分别减少 15.2%、20.5%、17.6%和 25.4%。FMLBC 降低了可交换态砷的分数，增加了土壤中非交换态砷的分数。此外，添加 FMLBC 显著降低了悬浮液中 As(III)的浓度（P < 0.05），而 As(V)或甲基砷酸浓度没有明显变化。添加 FMLBC 增加了土壤酶活性，改变了变形菌门和放线菌门的相对丰度。因此，FMLBC 影响砷挥发的机制可能包括以下两个方面：（1）FMLBC 影响土壤砷的转化和分布，降低砷的溶解、结晶和甲基化；（2）FMLBC 影响土壤性质，直接影响微生物活性，从而影响砷挥发。因此，FMLBC 可以降低砷的挥发性质，用于控制砷污染稻田中的砷挥发。
