中国环境科学

作者：刘莹, 韩智勇, 冯诗杰, 赵子亮, 常佳丽, 朱浩

单位：1. 成都理工大学生态环境学院, 地质灾害防治与地质环境保护国家重点实验室, 国家环境保护水土污染协同控制与联合修复重点实验室, 四川 成都 610059;2. 四川省林业科学研究院, 四川 成都 610081;3. 乐山师范学院新能源材料与化学学院, 四川 乐山 614004

关键词：氮,铁锰,生物转化,红层,地下水

基金：四川省自然科学基金资助重点项目(24NSFSC007)

The red beds vadose zone acts as a natural barrier against groundwater nitrogen pollution, but the influence of iron and manganese on the biotransformation of nitrogen remain unclear. Therefore, this study investigates the effects of Fe(III) and Mn(II) on the functional enzymes of dominant nitrifying and denitrifying bacterial species, as well as nitrogen conversion, mediated by the red beds vadose zone. The results showed that Acinetobacter and Pseudomonas were the dominant strains with the highest efficiency in nitrification and denitrification processes, respectively, in the vadose zone of the red beds. The optimal efficiency of nitrification and denitrification was observed at Fe(III) and Mn(II) concentrations of 20 and 10mg/L, respectively. However, inhibition of these processes occurred at concentrations around 30mg/L, and significant inhibition was observed at 60mg/L. The addition of sterilized red beds soil in the SFe0 group increased the activities of nitrification enzymes AMO and HAO by 4.69%~107.5% compared to the Fe0 group without red beds soil, promoting the conversion of NH+ 4 to NH2OH in the later stages. The activities of denitrification enzymes NAR, NIR, and NOS were increased by 9.16%~73.36%, facilitating the conversion of NO to N2O in the early stages. In the SMn(0) group, AMO and HAO activities were increased by 22.23%~120.29%, significantly promoting the conversion of NH2OH to NO2- and NO3- in the later stages. Overall, the activity of denitrifying enzymes NAR, NOR, and NOS was enhanced, promoting the conversion of NO2- to NO in the early stages. At optimal concentrations, the SFe20 group were increased in nitrification and denitrification rates of 58.91% and 121.17%, respectively, while the SMn10 group were increased by 42.17% and 55.68%. Under inhibitory concentrations, the SFe60 group showed an increase of 61.79% and 65.91% in nitrification and denitrification rates, respectively, while the SMn60 group increased by 30.26% and 80.03%. The red beds vadose zone effectively promotes nitrification and denitrification processes and alleviates the inhibitory effects of high concentrations of Fe(III) and Mn(II). Key words：nitrogen；iron and manganese；biotransformation；red beds；groundwater

来源：2024年第11期

《中国环境科学》期刊编辑部

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