State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.
Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.
J Environ Sci (China). 2024 Mar;137:515-526. doi: 10.1016/j.jes.2023.02.023. Epub 2023 Feb 24.
Arsenic (As) fate in paddy fields has been one of the most significant current issues due to the strong As accumulation potential of rice plants under flooded conditions. However, no attempt was done to explore As methylation and volatilization under non-flooded conditions. Herein, we investigated the effects of water management on As methylation and volatilization in three arsenic-contaminated soils enhanced by biostimulation with straw-derived organic matter and bioaugmentation with genetic engineered Pseudomonas putida KT2440 (GE P. putida). Under flooded conditions, the application of biochar (BC), rice straw (RS) and their combination (BC+RS) increased total As in porewater. However, these effects were greatly attenuated under non-flooded conditions. Compared with RS amendment alone, the combination of GE P. putida and RS further promoted the As methylation and volatilization, and the promotion percentage under non-flooded conditions were significantly higher than that under flooded conditions. The combined GE P. putida and RS showed the highest efficiency in As methylation (88 µg/L) and volatilization (415.4 µg/(kg·year)) in the non-flooded soil with moderate As contamination. Finally, stepwise multiple linear regression analysis presented that methylated As, DOC and pH in porewater were the most important factors contributing to As volatilization. Overall, our findings suggest that combination of bioaugmentation with GE P. putida and biostimulation with RS/BC+RS is a potential strategy for bioremediation of arsenic-contaminated soils by enhancing As methylation and volatilization under non-flooded conditions.
砷（As）在稻田中的命运是当前最受关注的问题之一，这是由于在淹水条件下，水稻植物具有很强的砷积累潜力。然而，目前还没有人试图探索非淹水条件下砷的甲基化和挥发作用。在此，我们研究了水分管理对生物刺激用秸秆衍生有机物和基因工程假单胞菌 KT2440（GE P. putida）生物强化增强的三种砷污染土壤中砷甲基化和挥发作用的影响。在淹水条件下，生物炭（BC）、稻草（RS）及其组合（BC+RS）的应用增加了孔隙水中的总砷。然而，在非淹水条件下，这些影响大大减弱。与单独添加 RS 相比，GE P. putida 和 RS 的组合进一步促进了砷的甲基化和挥发，并且非淹水条件下的促进百分比明显高于淹水条件下的促进百分比。在中度砷污染的非淹水土壤中，组合使用 GE P. putida 和 RS 表现出最高的砷甲基化效率（88 µg/L）和挥发效率（415.4 µg/（kg·年））。最后，逐步多元线性回归分析表明，孔隙水中的甲基化砷、DOC 和 pH 是促进砷挥发的最重要因素。总的来说，我们的研究结果表明，GE P. putida 生物强化与 RS/BC+RS 生物刺激相结合是通过增强非淹水条件下砷的甲基化和挥发作用来修复砷污染土壤的一种潜在策略。
