Xavier Marc Thevenot, Tomy Roy, Eva Pakostova, Etienne Bélanger, Eric Rosa, Lucie Coudert, Nadia Mykytczuk, Carmen Mihaela Neculita
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Speciation of As revealed depth-dependent redox processes, with As(V) dominating surface layer (0–30 cm), As(III) proportions increased in the middle layer (30–60 cm), while in the deepest layer (60-90 cm), MMA(V) becomes the predominant methylated form. Isotopic analyses (<span><span style=\"\"></span><span style=\"font-size: 90%; display: inline-block;\" tabindex=\"0\"><svg focusable=\"false\" height=\"3.702ex\" role=\"img\" style=\"vertical-align: -1.389ex;\" viewbox=\"0 -995.6 3572.2 1593.7\" width=\"8.297ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><g is=\"true\"><g is=\"true\"><g is=\"true\"><use xlink:href=\"#MJMATHI-3B4\"></use></g></g><g is=\"true\" transform=\"translate(453,444)\"><use transform=\"scale(0.707)\" xlink:href=\"#MJMAIN-33\"></use><use transform=\"scale(0.707)\" x=\"500\" xlink:href=\"#MJMAIN-34\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1261,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-53\"></use></g><g is=\"true\" transform=\"translate(556,-296)\"><g is=\"true\"><use transform=\"scale(0.707)\" xlink:href=\"#MJMAIN-53\"></use><use transform=\"scale(0.707)\" x=\"556\" xlink:href=\"#MJMAIN-4F\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(943,306)\"><g is=\"true\"><use transform=\"scale(0.5)\" xlink:href=\"#MJMAIN-32\"></use></g><g is=\"true\" transform=\"translate(250,0)\"><use transform=\"scale(0.5)\" xlink:href=\"#MJMAIN-2212\"></use></g></g><g is=\"true\" transform=\"translate(943,-202)\"><use transform=\"scale(0.5)\" xlink:href=\"#MJMAIN-34\"></use></g></g></g></g></g></svg></span><script type=\"math/mml\"><math><mrow is=\"true\"><msup is=\"true\"><mrow is=\"true\"><mi is=\"true\">δ</mi></mrow><mn is=\"true\">34</mn></msup><msub is=\"true\"><mi mathvariant=\"normal\" is=\"true\">S</mi><msubsup is=\"true\"><mtext is=\"true\">SO</mtext><mn is=\"true\">4</mn><mrow is=\"true\"><mn is=\"true\">2</mn><mo is=\"true\">−</mo></mrow></msubsup></msub></mrow></math></script></span>) and sulfate concentration profiles suggest localized hotspots of microbial sulfate reduction (MSR) in anoxic layers, associated with higher <span><span style=\"\"></span><span style=\"font-size: 90%; display: inline-block;\" tabindex=\"0\"><svg focusable=\"false\" height=\"3.702ex\" role=\"img\" style=\"vertical-align: -1.389ex;\" viewbox=\"0 -995.6 3572.2 1593.7\" width=\"8.297ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><g is=\"true\"><g is=\"true\"><g is=\"true\"><use xlink:href=\"#MJMATHI-3B4\"></use></g></g><g is=\"true\" transform=\"translate(453,444)\"><use transform=\"scale(0.707)\" xlink:href=\"#MJMAIN-33\"></use><use transform=\"scale(0.707)\" x=\"500\" xlink:href=\"#MJMAIN-34\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1261,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-53\"></use></g><g is=\"true\" transform=\"translate(556,-296)\"><g is=\"true\"><use transform=\"scale(0.707)\" xlink:href=\"#MJMAIN-53\"></use><use transform=\"scale(0.707)\" x=\"556\" xlink:href=\"#MJMAIN-4F\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(943,306)\"><g is=\"true\"><use transform=\"scale(0.5)\" xlink:href=\"#MJMAIN-32\"></use></g><g is=\"true\" transform=\"translate(250,0)\"><use transform=\"scale(0.5)\" xlink:href=\"#MJMAIN-2212\"></use></g></g><g is=\"true\" transform=\"translate(943,-202)\"><use transform=\"scale(0.5)\" xlink:href=\"#MJMAIN-34\"></use></g></g></g></g></g></svg></span><script type=\"math/mml\"><math><mrow is=\"true\"><msup is=\"true\"><mrow is=\"true\"><mi is=\"true\">δ</mi></mrow><mn is=\"true\">34</mn></msup><msub is=\"true\"><mi mathvariant=\"normal\" is=\"true\">S</mi><msubsup is=\"true\"><mtext is=\"true\">SO</mtext><mn is=\"true\">4</mn><mrow is=\"true\"><mn is=\"true\">2</mn><mo is=\"true\">−</mo></mrow></msubsup></msub></mrow></math></script></span> (> 12.0‰) and lower sulfate concentrations (61 to 10 mg/L). These spots aligned with high relative abundances of sulfate-reducing bacteria, suggesting As immobilization via As–S complexes and FeAsS/AsS precipitates. Microbial analyses showed stable α-diversity of prokaryotic communities, but significant variation among fungal populations. β-diversity differed significantly within the vertical profile of the biofilter, suggesting depth-dependent shifts in the composition of both prokaryotic and fungal communities. Functional taxa involved in S, Fe, and As cycling showed depth-dependent distributions, reflecting stratified redox conditions and biogeochemical processes. These findings highlight the role of coupled microbial and geochemical processes in sustaining As immobilization over decades and support the use of engineered organic biofilters as long-term passive treatment systems for As-NMD.","PeriodicalId":443,"journal":{"name":"Water Research","volume":"72 1","pages":""},"PeriodicalIF":12.4000,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Water Research","FirstCategoryId":"93","ListUrlMain":"https://doi.org/10.1016/j.watres.2025.124756","RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, ENVIRONMENTAL","Score":null,"Total":0}
引用次数: 0
Abstract
The long-term performance of a woodchip-based field-scale biofilter (50 m x 57 m x 1 m) treating As-rich neutral mine drainage (As-NMD) at the restored Wood-Cadillac mine site (Québec, Canada) was assessed. Operated for over 22 years, the biofilter showed up to 80% As removal efficiency, decreasing As influent concentration from 0.35 to < 0.1 mg/L, and complying with Canadian regulation. Speciation of As revealed depth-dependent redox processes, with As(V) dominating surface layer (0–30 cm), As(III) proportions increased in the middle layer (30–60 cm), while in the deepest layer (60-90 cm), MMA(V) becomes the predominant methylated form. Isotopic analyses () and sulfate concentration profiles suggest localized hotspots of microbial sulfate reduction (MSR) in anoxic layers, associated with higher (> 12.0‰) and lower sulfate concentrations (61 to 10 mg/L). These spots aligned with high relative abundances of sulfate-reducing bacteria, suggesting As immobilization via As–S complexes and FeAsS/AsS precipitates. Microbial analyses showed stable α-diversity of prokaryotic communities, but significant variation among fungal populations. β-diversity differed significantly within the vertical profile of the biofilter, suggesting depth-dependent shifts in the composition of both prokaryotic and fungal communities. Functional taxa involved in S, Fe, and As cycling showed depth-dependent distributions, reflecting stratified redox conditions and biogeochemical processes. These findings highlight the role of coupled microbial and geochemical processes in sustaining As immobilization over decades and support the use of engineered organic biofilters as long-term passive treatment systems for As-NMD.
期刊介绍:
Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include:
•Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management;
•Urban hydrology including sewer systems, stormwater management, and green infrastructure;
•Drinking water treatment and distribution;
•Potable and non-potable water reuse;
•Sanitation, public health, and risk assessment;
•Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions;
•Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment;
•Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution;
•Environmental restoration, linked to surface water, groundwater and groundwater remediation;
•Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts;
•Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle;
•Socio-economic, policy, and regulations studies.