作者机构：
[Tan, Wenfa; Ding, DX; Ding, Dexin; Yu, Huang; Hu, Nan] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;[Yan, Qingyun; Zhang, Dandan; Yan, QY; He, Zhili; Yu, Huang; Liu, Huanping; Chen, Pubo] Sun Yat Sen Univ, Marine Synthet Ecol Res Ctr, China ASEAN Belt & Rd Joint Lab Mariculture Techn, Southern Marine Sci & Engn Guangdong Lab Zhuhai,G, Zhuhai 519082, Peoples R China.;[Liu, Shengwei] Univ Warwick, Sch Life Sci, Coventry CV4 7AL, W Midlands, England.;[Hu, Ruiwen] Lawrence Berkeley Natl Lab, Environm Genom & Syst Biol Div, Berkeley, CA 94720 USA.;[Zhou, Qiang] Jishou Univ, Coll Biol & Environm Sci, Jishou 416000, Xiangxi Tujia &, Peoples R China.
通讯机构：
[Yan, QY ] S;[Ding, DX ] U;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Mi, Hengyang 421001, Peoples R China.;Sun Yat Sen Univ, Marine Synthet Ecol Res Ctr, China ASEAN Belt & Rd Joint Lab Mariculture Techn, Southern Marine Sci & Engn Guangdong Lab Zhuhai,G, Zhuhai 519082, Peoples R China.
关键词：
arsenic methylation;dissimilatory nitrate reduction to ammonium;microorganism enrichment;nitrogen fixation;phytoremediation
摘要：
Plants can recruit microorganisms to enhance soil arsenic (As) removal and nitrogen (N) turnover, but how microbial As methylation in the rhizosphere is affected by N biotransformation is not well understood. Here, we used acetylene reduction assay, arsM gene amplicon, and metagenome sequencing to evaluate the influence of N biotransformation on As methylation in the rhizosphere of Vetiveria zizanioides, a potential As hyperaccumulator. V. zizanioides was grown in mining soils (MS) and artificial As-contaminated soils (AS) over two generations in a controlled pot experiment. Results showed that the content of dimethylarsinic acid in the rhizosphere was significantly positively correlated with the rate of N fixation and the activity of nitrite reductase. The As-methylating species (e.g., Flavisolibacter and Paraflavitalea) were significantly enriched in the root-associated compartments in the second generation of MS and AS. Notably, higher abundance of genes involved in N fixation (nifD, nifK) and dissimilatory nitrate reduction to ammonium (narG/H, nirB/D/K/S) was detected in the second generation of MS than in the first generation. The metabolic pathway analysis further demonstrated that N fixing-stimulative and DNRA-stimulative As-methylating species could provide ammonium to enhance the synthesis of S-adenosyl-l-methionine, serving as methyl donors for soil As methylation. This study highlights two important N conversion-stimulative As-methylating pathways and has important implications for enhancing phytoremediation in As-contaminated soils.
摘要：
Mariculture has expanded significantly in recent decades due to rising seafood demand and its contribution to ocean carbon sequestration. While the mechanisms of carbon sequestration in mariculture are well-established, the roles of microorganisms in sedimentary carbon sequestration have rarely been explored. How microorganisms mediate organic carbon metabolism and their effects on coastal carbon pools remain unclear. Here we tested the carbon fraction and contents, as well as extracellular hydrolase activities in macroalgae culture area, fish or abalone culture area, and control area without mariculture. We profiled microbial community composition and carbon metabolism characteristics in sediments through 16S rRNA gene amplicon sequencing and metagenomics. Our findings revealed that macroalgae culture areas exhibited a significantly greater potential for carbon sequestration than the control area, the concentration of TOC in seawater and the contents of SOC, DOC, and ROC in sediments were significantly ( p < 0.05) increased by 18.93 %, 6.98 %, 33.98 %, and 18.30 % respectively. These results can be attributed to decreased activities of extracellular hydrolase and a lower abundance of carbon-degrading genes. Moreover, metabolic profiling identified taxa from families such as Alteromonadaceae , Pseudomonadaceae , Rhodobacteraceae , Enterobacteriaceae , and Flavobacteriaceae , which are highly metabolically flexible in utilizing a wide range of organic and inorganic energy sources, playing crucial roles in carbon formation. Their respiratory metabolism, such as sulfate reduction, thiosulfate oxidation, and denitrification as well as secondary metabolism products could also affect the formation and persistence of sedimentary carbon pools. Specifically, increased total nitrogen (TN) and nitrate-nitrogen (NO 3 − ) could potentially enhance microbial degradation of organic carbon, decreasing carbon stock within coastal sediments. This study enhanced our understanding of microbial regulation of the organic carbon pool in the mariculture ecosystem.
Mariculture has expanded significantly in recent decades due to rising seafood demand and its contribution to ocean carbon sequestration. While the mechanisms of carbon sequestration in mariculture are well-established, the roles of microorganisms in sedimentary carbon sequestration have rarely been explored. How microorganisms mediate organic carbon metabolism and their effects on coastal carbon pools remain unclear. Here we tested the carbon fraction and contents, as well as extracellular hydrolase activities in macroalgae culture area, fish or abalone culture area, and control area without mariculture. We profiled microbial community composition and carbon metabolism characteristics in sediments through 16S rRNA gene amplicon sequencing and metagenomics. Our findings revealed that macroalgae culture areas exhibited a significantly greater potential for carbon sequestration than the control area, the concentration of TOC in seawater and the contents of SOC, DOC, and ROC in sediments were significantly ( p < 0.05) increased by 18.93 %, 6.98 %, 33.98 %, and 18.30 % respectively. These results can be attributed to decreased activities of extracellular hydrolase and a lower abundance of carbon-degrading genes. Moreover, metabolic profiling identified taxa from families such as Alteromonadaceae , Pseudomonadaceae , Rhodobacteraceae , Enterobacteriaceae , and Flavobacteriaceae , which are highly metabolically flexible in utilizing a wide range of organic and inorganic energy sources, playing crucial roles in carbon formation. Their respiratory metabolism, such as sulfate reduction, thiosulfate oxidation, and denitrification as well as secondary metabolism products could also affect the formation and persistence of sedimentary carbon pools. Specifically, increased total nitrogen (TN) and nitrate-nitrogen (NO 3 − ) could potentially enhance microbial degradation of organic carbon, decreasing carbon stock within coastal sediments. This study enhanced our understanding of microbial regulation of the organic carbon pool in the mariculture ecosystem.
期刊：
Journal of Environmental Radioactivity,2025年287:107729 ISSN：0265-931X
通讯作者：
Ye, YJ
作者机构：
[Ye, Yongjun; Yao, Xuanli; Chen, Daijia] Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.;[Ye, Yongjun] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Min, Hengyang 421001, Peoples R China.;[Ye, Yongjun; Hong, Yufei] Univ South China, Natl & Local Joint Engn Res Ctr Airborne Pollutant, Hengyang 421001, Peoples R China.
通讯机构：
[Ye, YJ ] U;Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.
关键词：
Active depressurization;CFD;Covered layer;Fracture;Radon;Radon exhalation rate
摘要：
In underground engineering, a covered layer is usually established to provide certain support and protection for underground tunnels. At the same time, the covered layer can also inhibit radon exhalation from surrounding rock. To study radon exhalation in the covered layer and surrounding rock of a tunnel, and to control radon migration in tunnels with fracture-pore covered layers, a specific underground tunnel was chosen for analysis. A radon migration and dynamics model in the fracture-pore medium was developed, and computational fluid dynamics (CFD) simulations were performed to analyze the radon exhalation from the covered layer and surrounding rock. The impact of factors like pressure difference, diffusion coefficient, and permeability on the radon exhalation rate was examined. The results indicated that adjusting these parameters could effectively manage the radon exhalation rate, with a particular focus on the proposed active depressurization (AD) method, which can significantly reduce the radon exhalation rate and provide scientific basis for radon pollution control in underground engineering.
In underground engineering, a covered layer is usually established to provide certain support and protection for underground tunnels. At the same time, the covered layer can also inhibit radon exhalation from surrounding rock. To study radon exhalation in the covered layer and surrounding rock of a tunnel, and to control radon migration in tunnels with fracture-pore covered layers, a specific underground tunnel was chosen for analysis. A radon migration and dynamics model in the fracture-pore medium was developed, and computational fluid dynamics (CFD) simulations were performed to analyze the radon exhalation from the covered layer and surrounding rock. The impact of factors like pressure difference, diffusion coefficient, and permeability on the radon exhalation rate was examined. The results indicated that adjusting these parameters could effectively manage the radon exhalation rate, with a particular focus on the proposed active depressurization (AD) method, which can significantly reduce the radon exhalation rate and provide scientific basis for radon pollution control in underground engineering.
摘要：
Uranium is the core material for the development of the nuclear industry, but its irreversible radiation damage poses a significant threat to human health. In this context, an innovative dual-mode colorimetric and electrochemical sensor was developed for the detection of uranyl ions (UO(2)(2+)), utilizing a covalent organic framework@gold nanoclusters (AuNCs@COF) composite. The synthesis of AuNCs@COF was simple, and the incorporation of AuNCs imparted the composite with exceptional peroxidase-like catalytic activity and enhanced electrochemical properties. By regulating the adsorption and desorption of aptamers on the AuNCs@COF surface, both peroxidase-like activity and conductivity were modulated, enabling the detection of UO(2)(2+) utilizing colorimetric and electrochemical dual signals. Under optimal conditions, the sensor revealed a broad linear detection range and a low detection limit, with ranges of 1.36 × 10(-10)-1.36 × 10(-5)mol/L for colorimetric detection and 5.0 × 10(-10)-2.5 × 10(-5)mol/L for electrochemical detection, achieving detection limitsfor these two methodsof 107 pmol/L and 347 pmol/L, respectively. Unlike other single-mode sensorsfor UO(2)(2+) detection, this dual-mode sensor demonstrated superior sensitivity, specificity, and repeatability. Furthermore, the results of spiked recovery experiments in real water samples highlight the promising potential of this dual-mode sensor for environmental water monitoring applications.
摘要：
Uranium (U) can impact microbially driven soil phosphorus (P) and carbon (C) cycling. However, the response of microbial P and C turnover to U in different soils is not well understood. Through the quantitative assay of P pools and soil organic C (SOC) quantitative assay and sequencing of 16S rRNA gene amplicons and metagenomes, we investigated the effect of U on P and C biotransformation in grassland (GL), paddy soil (PY), forest soil (FT). U (60 mg kg -1 ) impacted the diversity, interaction and stability of soil bacterial communities, leading to a decrease in available P (AP). Under U stress, organophosphate mineralization substantially contributed to the AP in GL and FT, whereas intracellular P metabolism dominated the AP in PY. Also, the reductive citrate cycle (rTCA cycle) promoted the content of SOC in GL, while the rTCA cycle and complex organic C degradation pathways enhanced the SOC in PY and FT, respectively. Notably, functional bacteria carrying organic C degradation genes could decompose SOC to enhance soil AP. Bacteria developed various resistance strategies to cope with U stress. This study reveals soil-dependent response of microbial P and C cycling and its ecological functions under the influence of radioactive contaminants in different soil systems.
Uranium (U) can impact microbially driven soil phosphorus (P) and carbon (C) cycling. However, the response of microbial P and C turnover to U in different soils is not well understood. Through the quantitative assay of P pools and soil organic C (SOC) quantitative assay and sequencing of 16S rRNA gene amplicons and metagenomes, we investigated the effect of U on P and C biotransformation in grassland (GL), paddy soil (PY), forest soil (FT). U (60 mg kg -1 ) impacted the diversity, interaction and stability of soil bacterial communities, leading to a decrease in available P (AP). Under U stress, organophosphate mineralization substantially contributed to the AP in GL and FT, whereas intracellular P metabolism dominated the AP in PY. Also, the reductive citrate cycle (rTCA cycle) promoted the content of SOC in GL, while the rTCA cycle and complex organic C degradation pathways enhanced the SOC in PY and FT, respectively. Notably, functional bacteria carrying organic C degradation genes could decompose SOC to enhance soil AP. Bacteria developed various resistance strategies to cope with U stress. This study reveals soil-dependent response of microbial P and C cycling and its ecological functions under the influence of radioactive contaminants in different soil systems.
期刊：
Science of The Total Environment,2025年958:177896 ISSN：0048-9697
通讯作者：
Dexin Ding
作者机构：
[Li, Guangyue; Li, Aishu; Yi, Haitao; Wang, Yongdong; Wang, Haonan] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Heng Yang 421001, Hunan, PR China;[Ding, Dexin] Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Heng Yang 421001, Hunan, PR China. Electronic address: Ddingusc@163.com
通讯机构：
[Dexin Ding] K;Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Heng Yang 421001, Hunan, PR China
关键词：
Acidic groundwater;In site bioremediation;Nitrate;Tumebacillus;Uranium
摘要：
In-situ leaching (ISL) is the predominant technology used in uranium mining currently, although it leads to significant environmental challenges. Nitrates, a key component in leaching agents, not only pose a threat to human health but also impede the bioreduction of U(VI) in uranium-contaminated water. In this study, the nitrate reducing bacterial (NRB) communities adapted to acidic uranium-contaminated groundwater from a site in Northwest China were gained by an enrichment micro-model. The effects of the NRB communities on the groundwater parameters and microbial diversity were evaluated using the groundwater-core column leaching system during the in-situ bioremediation of nitrate. The enrichment experiments revealed that NRB communities adapted to acidic uranium-contaminated groundwater were successfully enriched, of which Tumebacillus was the main functional bacterium. The column leaching experiment results showed that adding NRB communities successfully reduced nitrate levels from 100.91 mg/L to 0.7 mg/L in just 8 days, improved groundwater acidity and redox conditions. Additionally, the metagenomic analysis showed that introducing NRB communities increased biomass and indigenous NRB, but decreased microbial diversity. The KEGG enrichment analysis suggested that butanoate metabolism and valine, leucine and isoleucine degradation were promoted by adding enriched NRB communities. This research lays the groundwork for nitrate removal from contaminated groundwater in areas affected by ISL in uranium mines, setting the stage for future in situ bioremediation of U(VI).
In-situ leaching (ISL) is the predominant technology used in uranium mining currently, although it leads to significant environmental challenges. Nitrates, a key component in leaching agents, not only pose a threat to human health but also impede the bioreduction of U(VI) in uranium-contaminated water. In this study, the nitrate reducing bacterial (NRB) communities adapted to acidic uranium-contaminated groundwater from a site in Northwest China were gained by an enrichment micro-model. The effects of the NRB communities on the groundwater parameters and microbial diversity were evaluated using the groundwater-core column leaching system during the in-situ bioremediation of nitrate. The enrichment experiments revealed that NRB communities adapted to acidic uranium-contaminated groundwater were successfully enriched, of which Tumebacillus was the main functional bacterium. The column leaching experiment results showed that adding NRB communities successfully reduced nitrate levels from 100.91 mg/L to 0.7 mg/L in just 8 days, improved groundwater acidity and redox conditions. Additionally, the metagenomic analysis showed that introducing NRB communities increased biomass and indigenous NRB, but decreased microbial diversity. The KEGG enrichment analysis suggested that butanoate metabolism and valine, leucine and isoleucine degradation were promoted by adding enriched NRB communities. This research lays the groundwork for nitrate removal from contaminated groundwater in areas affected by ISL in uranium mines, setting the stage for future in situ bioremediation of U(VI).
摘要：
Mercury (Hg) pollution poses a critical threat to human health and the environment, necessitating urgent control measures. This study introduces a novel modification method for the common zero-valent iron-carbon (ZVI-AC) galvanic cells using a two-step process, nonthermal (NTP) irradiation followed by targeted functionalization, aiming to enhance Hg adsorption potential by adjusting the physicochemical properties of the cells. The NTP irradiated functionalized adsorbent demonstrated superior Hg adsorption performance across various concentrations and pH variations. Multichannel adsorption mechanisms were confirmed by fitting a total of 22 different adsorption isotherm models, indicating the coexistence of monolayer and multilayer adsorption processes. The NTP irradiation modifies the ZVI and AC, inducing nitrogen and oxygen doping on carbon-based surfaces and oxidizing ZVI to Fe(II)-Fe(III) species. The deepened oxidation of Fe in NTP-Fe-C, coupled with Hg 2+ reduction to elemental Hg by raw Fe, contributed to Hg removal. NTP irradiation facilitated electron transfer between Fe and Hg, promoting oxidation of Fe and reduction of Hg 2+ cations. The emergence of diverse Hg species further supported the multichannel adsorption/removal mechanism achieved by NTP-irradiated cells. This method offers a promising solution to Hg pollution and expands the application of the traditional iron-carbon galvanic cells in treating hazardous heavy metal wastes.
Mercury (Hg) pollution poses a critical threat to human health and the environment, necessitating urgent control measures. This study introduces a novel modification method for the common zero-valent iron-carbon (ZVI-AC) galvanic cells using a two-step process, nonthermal (NTP) irradiation followed by targeted functionalization, aiming to enhance Hg adsorption potential by adjusting the physicochemical properties of the cells. The NTP irradiated functionalized adsorbent demonstrated superior Hg adsorption performance across various concentrations and pH variations. Multichannel adsorption mechanisms were confirmed by fitting a total of 22 different adsorption isotherm models, indicating the coexistence of monolayer and multilayer adsorption processes. The NTP irradiation modifies the ZVI and AC, inducing nitrogen and oxygen doping on carbon-based surfaces and oxidizing ZVI to Fe(II)-Fe(III) species. The deepened oxidation of Fe in NTP-Fe-C, coupled with Hg 2+ reduction to elemental Hg by raw Fe, contributed to Hg removal. NTP irradiation facilitated electron transfer between Fe and Hg, promoting oxidation of Fe and reduction of Hg 2+ cations. The emergence of diverse Hg species further supported the multichannel adsorption/removal mechanism achieved by NTP-irradiated cells. This method offers a promising solution to Hg pollution and expands the application of the traditional iron-carbon galvanic cells in treating hazardous heavy metal wastes.
通讯机构：
[Ding, Y ] U;Univ South China, Sch Resource & Environm & Safety Engn, Hengyang 421001, Peoples R China.;Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Min, Hengyang 421001, Peoples R China.
关键词：
DOM oxidation;Dissolved organic matter;Iron (oxyhydr)oxides;Mn oxides;Mn(II) oxidation
摘要：
The abiotic oxidation of divalent manganese (Mn(II)) and the formation of Mn oxides are important geochemical processes, which control the mobility and availability of Mn as well as element cycling and pollutant behavior in soils. It was found that iron (oxyhydr)oxides can catalyze Mn(II) oxidation, but the effects of the coexisting dissolved organic matter (DOM) molecules on the catalysis of different iron (oxyhydr)oxides for Mn(II) oxidation are poorly understood. Herein, we investigated Mn(II) oxidation under the impacts of the interactions between iron (oxyhydr)oxides (i.e., ferrihydrite, goethite and hematite) and DOM molecules. Simultaneously, we elucidated the variations of DOM composition and properties. Our results indicated that the catalysis of iron (oxyhydr)oxides for Mn(II) oxidation was significantly inhibited by DOM. Moreover, DOM had less inhibiting effect on the catalysis of ferrihydrite for Mn(II) oxidation and the formation of Mn oxides (e.g., hausmannite and buserite) relative to goethite and hematite, which was partially because of the higher electron transfer capacities of ferrihydrite. Meanwhile, DOM molecules with high nominal oxidation state of carbon (NOSC), molecular weight, unsaturation and aromaticity were selectively adsorbed and oxidized by Mn oxides, including the oxygenated phenols and polyphenols. The newly formed molecules mainly belonged to phenols depleted of oxygen and aliphatics. Furthermore, NOSC was a key molecular characteristic for controlling DOM composition during DOM adsorption and oxidation by Mn oxides when iron minerals were present. Overall, our research contributes to understanding Mn(II) oxidation mechanisms under heterogeneous systems and behaviors of DOM molecules in the environment.
The abiotic oxidation of divalent manganese (Mn(II)) and the formation of Mn oxides are important geochemical processes, which control the mobility and availability of Mn as well as element cycling and pollutant behavior in soils. It was found that iron (oxyhydr)oxides can catalyze Mn(II) oxidation, but the effects of the coexisting dissolved organic matter (DOM) molecules on the catalysis of different iron (oxyhydr)oxides for Mn(II) oxidation are poorly understood. Herein, we investigated Mn(II) oxidation under the impacts of the interactions between iron (oxyhydr)oxides (i.e., ferrihydrite, goethite and hematite) and DOM molecules. Simultaneously, we elucidated the variations of DOM composition and properties. Our results indicated that the catalysis of iron (oxyhydr)oxides for Mn(II) oxidation was significantly inhibited by DOM. Moreover, DOM had less inhibiting effect on the catalysis of ferrihydrite for Mn(II) oxidation and the formation of Mn oxides (e.g., hausmannite and buserite) relative to goethite and hematite, which was partially because of the higher electron transfer capacities of ferrihydrite. Meanwhile, DOM molecules with high nominal oxidation state of carbon (NOSC), molecular weight, unsaturation and aromaticity were selectively adsorbed and oxidized by Mn oxides, including the oxygenated phenols and polyphenols. The newly formed molecules mainly belonged to phenols depleted of oxygen and aliphatics. Furthermore, NOSC was a key molecular characteristic for controlling DOM composition during DOM adsorption and oxidation by Mn oxides when iron minerals were present. Overall, our research contributes to understanding Mn(II) oxidation mechanisms under heterogeneous systems and behaviors of DOM molecules in the environment.
摘要：
Phosphate-solubilizing bacteria (PSB) are important but often overlooked regulators of uranium (U) cycling in soil. However, the impact of PSB on uranate fixation coupled with the decomposition of recalcitrant phosphorus (P) in mining land remains poorly understood. Here, we combined gene amplicon sequencing, metagenome and metatranscriptome sequencing analysis and strain isolation to explore the effects of PSB on the stabilization of uranate and P availability in U mining areas. We found that the content of available phosphorus (AP), carbonate-U and Fe-Mn-U oxides in tailings was significantly (P < 0.05) higher than their adjacent soils. Also, organic phosphate mineralizing (PhoD) bacteria (e.g., Streptomyces) and inorganic phosphate solubilizing (gcd) bacteria (e.g., Rhodococcus) were enriched in tailings and soils, but only organic phosphate mineralizing-bacteria substantially contributed to the AP. Notably, most genes involved in organophosphorus mineralization and uranate resistance were widely present in tailings rather than soil. Comparative genomics analyses supported that organophosphorus mineralizing-Streptomyces species could increase soil AP content and immobilize U(VI) through organophosphorus mineralization (e.g., PhoD, ugpBAEC) and U resistance related genes (e.g., petA). We further demonstrated that the isolated Streptomyces sp. PSBY1 could enhance the U(VI) immobilization mediated by the NADH-dependent ubiquinol-cytochrome c reductase (petA) through decomposing organophosphorous compounds. This study advances our understanding of the roles of PSB in regulating the fixation of uranate and P availability in U tailings.
作者机构：
[Feng, Yu-Xuan; Huang, Tao] Changshu Inst Technol, Sch Mat Engn, Changshu 215500, Peoples R China.;[Huang, Tao] Changshu Inst Technol, Suzhou Key Lab Funct Ceram Mat, Changshu 215500, Peoples R China.;[Zhou, Lulu] Changzhou Univ, Sch Environm & Safety Engn, 1 Gehu Rd, Changzhou 213164, Peoples R China.;[Zhang, Shu-wen] Univ South China, Nucl Resources Engn Coll, Hengyang 421001, Peoples R China.
通讯机构：
[Huang, T ] C;Changshu Inst Technol, Sch Mat Engn, Changshu 215500, Peoples R China.
关键词：
Self-cementation;Arsenic-contaminated soil;Binary (hydro)oxides of polyvalent ferromanganese;Alkali-composite activation;Geopolymerization kinetics;Geopolymerization kinetics
摘要：
The self-cementation characteristics of arsenic (As)-contaminated soil were comprehensively investigated in this study. Different non-thermal plasma-irradiated binary (hydro)oxides of polyvalent ferromanganese (poly-Fe-Mn) were synthesized and exploratorily dispersed to soil samples to activate solidification and stabilization during the self-cemented process. The maximum compressive strength of 56.35MPa and the lowest leaching toxicity of 0.004mg/L were obtained in the proof test under optimal conditions (i.e., the mass ratio of the poly-Fe-Mn to the soil sample of 0.05; the mass ratio of the composite alkali activator (NaOH+CaO) to the soil sample of 0.25; the mass ratio of CaO to NaOH of 1.5; the mass ratio of the DI water to the binder of 0.515). The composite alkaline activator primarily contributed to the strength formation of the self-cemented matrix while the poly-Fe-Mn significantly influenced the reduction of the As-leaching toxicities. The poly-Fe-Mn maintained diffusion-controlled polycondensation and strengthened the nucleation process during self-cementation. The amount of water and the dosage of poly-Fe-Mn caused an interactive influence on the self-cemented solidification of contaminated soils. The solidified samples with poly-Fe-Mn exhibited better thermal decomposition than their counterparts, reflecting the enhancement of poly-Fe-Mn to the matrix. Some minerals including C-S-H, kaolinite, gehlenite, diopside sodian, augite, and albite were matched in the samples, directly demonstrating the geopolymerization-steered self-cementation of the As soil. The employment of poly-Fe-Mn not only reinforced the immobilization of As pollutants in the matrix but also induced the self-cementation of soils by intensifying the composite alkaline-activated geopolymerization kinetics.
作者机构：
[Liu, Shu Yuan; Ding, Ku Ke] Chinese Ctr Dis Control & Prevent, Natl Inst Radiol Protect, Beijing 100088, Peoples R China.;[Zhang, Li; Ding, Ku Ke] Chinese Ctr Dis Control & Prevent, Off Publ Hlth Management, Beijing 102206, Peoples R China.;[Ye, Yong Jun] Univ South China, Key Discipline Lab Natl Def Biotechnol Uranium Min, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Ding, KK ] C;Chinese Ctr Dis Control & Prevent, Natl Inst Radiol Protect, Beijing 100088, Peoples R China.;Chinese Ctr Dis Control & Prevent, Off Publ Hlth Management, Beijing 102206, Peoples R China.
关键词：
CFD;Coverage experiment;Optimized design;Radon retardation rate;Radon-containing water
摘要：
Objective This study aimed to efficiently reduce the release of radon from water bodies to protect the environment.
This study aimed to efficiently reduce the release of radon from water bodies to protect the environment.
Methods Based on the sizes of the experimental setup and modular float, computational fluid dynamics (CFD) was used to assess the impact of the area coverage rate, immersion depth, diffusion coefficient, and radon transfer velocity at the gas–liquid interface on radon migration and exhalation of radon-containing water. Based on the numerical simulation results, an estimation model for the radon retardation rate was constructed. The effectiveness of the CFD simulation was evaluated by comparing the experimental and simulated variation values of the radon retardation rate with the coverage area rates.
Based on the sizes of the experimental setup and modular float, computational fluid dynamics (CFD) was used to assess the impact of the area coverage rate, immersion depth, diffusion coefficient, and radon transfer velocity at the gas–liquid interface on radon migration and exhalation of radon-containing water. Based on the numerical simulation results, an estimation model for the radon retardation rate was constructed. The effectiveness of the CFD simulation was evaluated by comparing the experimental and simulated variation values of the radon retardation rate with the coverage area rates.
Results The effect of radon transfer velocity on radon retardation in water bodies was minor and insignificant according to the appropriate value; therefore, an estimation model of the radon retardation rate of the coverage of a radon-containing water body was constructed using the synergistic impacts of three factors: area coverage rate, immersion depth, and diffusion coefficient. The deviation between the experimental and simulated results was < 4.3%.
The effect of radon transfer velocity on radon retardation in water bodies was minor and insignificant according to the appropriate value; therefore, an estimation model of the radon retardation rate of the coverage of a radon-containing water body was constructed using the synergistic impacts of three factors: area coverage rate, immersion depth, and diffusion coefficient. The deviation between the experimental and simulated results was < 4.3%.
Conclusion Based on the numerical simulation conditions, an estimation model of the radon retardation rate of covering floats in water bodies under the synergistic effect of multiple factors was obtained, which provides a reference for designing covering floats for radon retardation in radon-containing water.
Based on the numerical simulation conditions, an estimation model of the radon retardation rate of covering floats in water bodies under the synergistic effect of multiple factors was obtained, which provides a reference for designing covering floats for radon retardation in radon-containing water.
关键词：
Efflux pumps;Heavy metal resistance;Secretome
摘要：
Heavy metal-resistant bacteria secrete extracellular proteins (e-PNs). However, the role of e-PNs in heavy metal resistance remains elusive. Here Fourier Transform Infrared Spectroscopy implied that N-H, C=O and NH(2)-R played a crucial role in the adsorption and resistance of Ni(2+) in the model organism Cuprividus pauculus 1490 (C. pauculus). Proteinase K treatment reduced Ni(2+) resistance of C. pauculus underlining the essential role of e-PNs. Further three-dimension excitation-emission matrix fluorescence spectroscopy analysis demonstrated that tryptophan proteins as part of the e-PNs increased significantly with Ni(2+) treatment. Proteomic and quantitative real-time polymerase chain reaction data indicated that major changes were induced in the metabolism of C. pauculus in response to Ni(2+). Among those lipopolysaccharide biosynthesis, general secretion pathways, Ni(2+)-affiliated transporters and multidrug efflux play an essential role in Ni(2+) resistance. Altogether the results provide a conceptual model for comprehending how e-PNs contribute to bacterial resistance and adsorption of Ni(2+).
摘要：
To investigate the strengthening effects and mechanisms of bioaugmentation on the microbial remediation of uranium-contaminated groundwater via bioreduction coupled to biomineralization, two exogenous microbial consortia with reducing and phosphate-solubilizing functions were screened and added to uranium-contaminated groundwater as the experimental groups (group B, reducing consortium added; group C, phosphate-solubilizing consortium added). β-glycerophosphate (GP) was selected to stimulate the microbial community as the sole electron donor and phosphorus source. The results showed that bioaugmentation accelerated the consumption of GP and the proliferation of key functional microbes in groups B and C. In group B, Dysgonomonas, Clostridium_sensu_stricto_11 and Clostridium_sensu_stricto_13 were the main reducing bacteria, and Paenibacillus was the main phosphate-solubilizing bacteria. In group C, the microorganisms that solubilized phosphate were mainly unclassified_f_Enterobacteriaceae. Additionally, bioaugmentation promoted the formation of unattached precipitates and alleviated the inhibitory effect of cell surface precipitation on microbial metabolism. As a result, the formation rate of U-phosphate precipitates and the removal rates of aqueous U(VI) in both groups B and C were elevated significantly after bioaugmentation. The U(VI) removal rate was poor in the control group (group A, with only an indigenous consortium). Propionispora, Sporomusa and Clostridium_sensu_stricto_11 may have played an important role in the removal of uranium in group A. Furthermore, the addition of a reducing consortium promoted the reduction of U(VI) to U(IV), and immobilized uranium existed in the form of U(IV)-phosphate and U(VI)-phosphate precipitates in group B. In contrast, U was present mainly as U(VI)-phosphate precipitates in groups A and C. Overall, bioaugmentation with an exogenous consortium resulted in the rapid removal of uranium from groundwater and the formation of U-phosphate minerals and served as an effective strategy for improving the treatment of uranium-contaminated groundwater in situ.
摘要：
An in vivo model is necessary for toxicology. This review analyzed the uses of zebrafish (Danio rerio) in toxicology based on bibliometrics. Totally 56,816 publications about zebrafish from 2002 to 2023 were found in Web of Science Core Collection, with Toxicology as the top 6 among all disciplines. Accordingly, the bibliometric map reveals that "toxicity" has become a hot keyword. It further reveals that the most common exposure types include acute, chronic, and combined exposure. The toxicological effects include behavioral, intestinal, cardiovascular, hepatic, endocrine toxicity, neurotoxicity, immunotoxicity, genotoxicity, and reproductive and transgenerational toxicity. The mechanisms include oxidative stress, inflammation, autophagy, and dysbiosis of gut microbiota. The toxicants commonly evaluated by using zebrafish model include nanomaterials, arsenic, metals, bisphenol, and dioxin. Overall, zebrafish provide a unique and well-accepted model to investigate the toxicological effects and mechanisms. We also discussed the possible ways to address some of the limitations of zebrafish model, such as the combination of human organoids to avoid species differences.
通讯机构：
[Yan, QY ] S;Sun Yat Sen Univ, Sch Environm Sci & Engn, Southern Marine Sci & Engn Guangdong Lab Zhuhai, State Key Lab Biocontrol,Sch Ecol,Guangdong Prov O, Guangzhou 510006, Peoples R China.
关键词：
Metabolic pathway;Metagenomic analysis;Microbial coupling;Nitrogen and sulfur cycling
摘要：
Microorganisms play important roles in the biogeochemical cycles of lake sediment. However, the integrated metabolic mechanisms governing nitrogen (N) and sulfur (S) cycling in eutrophic lakes remain poorly understood. Here, metagenomic analysis of field and bioreactor enriched sediment samples from a typical eutrophic lake were applied to elucidate the metabolic coupling of N and S cycling. Our results showed significant diverse genes involved in the pathways of dissimilatory sulfur metabolism, denitrification and dissimilatory nitrate reduction to ammonium (DNRA). The N and S associated functional genes and microbial groups generally showed significant correlation with the concentrations of NH(4)(+), NO(2)(-) and SO(4)(2), while with relatively low effects from other environmental factors. The gene-based co-occurrence network indicated clear cooperative interactions between N and S cycling in the sediment. Additionally, our analysis identified key metabolic processes, including the coupled dissimilatory sulfur oxidation (DSO) and DNRA as well as the association of thiosulfate oxidation complex (SOX systems) with denitrification pathway. However, the enriched N removal microorganisms in the bioreactor ecosystem demonstrated an additional electron donor, incorporating both the SOX systems and DSO processes. Metagenome-assembled genomes-based ecological model indicated that carbohydrate metabolism is the key linking factor for the coupling of N and S cycling. Our findings uncover the coupling mechanisms of microbial N and S metabolism, involving both inorganic and organic respiration pathways in lake sediment. This study will enhance our understanding of coupled biogeochemical cycles in lake ecosystems.
作者机构：
[Huang, Tao; Zhou, Lulu; Yang, Chun-Hai] Changshu Inst Technol, Sch Mat Engn, Changshu 215500, Peoples R China.;[Huang, Tao] Changshu Inst Technol, Suzhou Key Lab Funct Ceram Mat, Changshu 215500, Peoples R China.;[Huang, Tao] China Univ Min & Technol, Sch Chem Engn & Technol, Xuzhou 221116, Jiangsu, Peoples R China.;[Zhang, Shu-wen] Univ South China, Nucl Resources Engn Coll, Hengyang 421001, Peoples R China.
通讯机构：
[Tao Huang] S;School of Materials Engineering, Changshu Institute of Technology, 215500, China<&wdkj&>Suzhou Key Laboratory of Functional Ceramic Materials, Changshu Institute of Technology, Changshu, 215500, China<&wdkj&>School of Chemical Engineering & Technology, China University of Mining and Technology, Xuzhou, Jiangsu, 221116, China
