作者机构：
[Chen, Shengbin; Fu, Yusong; Liu, Yingjiu; Zeng, Taotao; Deng, Qiqi] Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang, 421001, Hunan, China;[Yang, Min] School of Environment and Civil Engineering, Harbin Institute of Technology (Shenzhen), Shenzheng 518055, China;[Yang, Min] Hunan Vch Environment Technology Co., Ltd, Changsha, 410014, China;[Li, Jun] College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China. Electronic address: jun.li@cqu.edu.cn
通讯机构：
[Jun Li] C;College of Environment and Ecology, Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing, 400045, China
关键词：
Acidic wastewater;Biochar;U(VI) removal;ZVMn
摘要：
The chemical and radiological toxicity of uranium can present a significant risk to both human health and environmental safety. Thus, ZVMn-BC was synthesized through borohydride reduction aimed at investigating its performance in removing U(VI) in acidic environment (pH = 3). Several batch experiments were conducted to assess the sorption capability under various operational conditions and the relevant experimental data were investigated by kinetics, isotherms and thermodynamic equations. ZVMn-BC exhibited excellent resistance to interference and showed a superiority on U(VI) removal over zerovalent manganese (ZVMn) and corn straw biochar (BC). Under condition of pH 3, and ambient temperature of 303 K with 0.4 g/L of adsorbent, ZVMn-BC exhibited a theoretical sorption quantity of 274.78 mg/g. The sorption process was spontaneous and endothermic, primarily relying on chemical adsorption. The interaction mechanism involved electrostatic interaction, hydrolysis precipitation, complexation, and redox reactions. This study verified that ZVMn-BC exhibits effective performance for U(VI) eliminating in acidic wastewater.
The chemical and radiological toxicity of uranium can present a significant risk to both human health and environmental safety. Thus, ZVMn-BC was synthesized through borohydride reduction aimed at investigating its performance in removing U(VI) in acidic environment (pH = 3). Several batch experiments were conducted to assess the sorption capability under various operational conditions and the relevant experimental data were investigated by kinetics, isotherms and thermodynamic equations. ZVMn-BC exhibited excellent resistance to interference and showed a superiority on U(VI) removal over zerovalent manganese (ZVMn) and corn straw biochar (BC). Under condition of pH 3, and ambient temperature of 303 K with 0.4 g/L of adsorbent, ZVMn-BC exhibited a theoretical sorption quantity of 274.78 mg/g. The sorption process was spontaneous and endothermic, primarily relying on chemical adsorption. The interaction mechanism involved electrostatic interaction, hydrolysis precipitation, complexation, and redox reactions. This study verified that ZVMn-BC exhibits effective performance for U(VI) eliminating in acidic wastewater.
作者机构：
[Zhang, Jingwei; Wang, Weinan; Sha, Haichao; Gao, Ji; Ge, Lukun; Li, Xi] Xi'an Key Laboratory of Environmental Simulation and Ecological Health in the Yellow River Basin, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China;[Li, Qi] Xi'an Key Laboratory of Environmental Simulation and Ecological Health in the Yellow River Basin, College of Urban and Environmental Sciences, Northwest University, Xi'an 710127, China. Electronic address: qili726@nwu.edu.cn;[Zeng, Taotao] Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang, Hunan 421001, China
通讯机构：
[Qi Li] X;Xi'an Key Laboratory of Environmental Simulation and Ecological Health in the Yellow River Basin, College of Urban and Environmental Sciences, Northwest University, 710127, Xi'an China
摘要：
Zebrafish, as a model organism, exhibit high sensitivity to environmental pollutants and has been widely used in microplastics (MPs) toxicology studies. However, the mechanisms underlying MPs’ effects on zebrafish have yet to be comprehensively summarized. This review systematically explores the sources, pollution status of freshwater MPs and their biological toxicity mechanisms using zebrafish as a model organism. This analysis reveals that the primary sources of MPs include sediment release, natural degradation of plastic products, and precipitation-mediated transport. Freshwater MPs predominantly comprise of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), and polyvinyl chloride (PVC). These MPs typically appear transparent, white, black, or blue, and predominantly exist as fibers, films, fragments, foams, and particles. The concentration, size, shape, type, aging status, and loading capacity of MPs can induce developmental malformations in zebrafish embryos, including pericardial and yolk sac edema. In adult zebrafish, MPs cause intestinal injuries characterized by increased permeability, impaired barrier function, and microbiota dysbiosis. MPs exposure also induces behavioral abnormalities such as reduced locomotion and anxiety-like responses, while simultaneously provoking oxidative stress and immune-inflammatory reactions. The physical mechanism of MPs-induced toxicity in zebrafish involves particle accumulation and tissue abrasion. In contrast, physiological and molecular mechanisms encompass interactions between MPs’ surface functional groups and biological tissues, alterations in oxidative stress markers, enzymatic activity and cytokine profiles, and modulation of gene expression patterns. This review synthesizes current knowledge on the ecological risks of freshwater MP pollution and its toxicological impacts on zebrafish, thereby providing a comprehensive framework for understanding MP toxicity mechanisms.
Zebrafish, as a model organism, exhibit high sensitivity to environmental pollutants and has been widely used in microplastics (MPs) toxicology studies. However, the mechanisms underlying MPs’ effects on zebrafish have yet to be comprehensively summarized. This review systematically explores the sources, pollution status of freshwater MPs and their biological toxicity mechanisms using zebrafish as a model organism. This analysis reveals that the primary sources of MPs include sediment release, natural degradation of plastic products, and precipitation-mediated transport. Freshwater MPs predominantly comprise of polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), and polyvinyl chloride (PVC). These MPs typically appear transparent, white, black, or blue, and predominantly exist as fibers, films, fragments, foams, and particles. The concentration, size, shape, type, aging status, and loading capacity of MPs can induce developmental malformations in zebrafish embryos, including pericardial and yolk sac edema. In adult zebrafish, MPs cause intestinal injuries characterized by increased permeability, impaired barrier function, and microbiota dysbiosis. MPs exposure also induces behavioral abnormalities such as reduced locomotion and anxiety-like responses, while simultaneously provoking oxidative stress and immune-inflammatory reactions. The physical mechanism of MPs-induced toxicity in zebrafish involves particle accumulation and tissue abrasion. In contrast, physiological and molecular mechanisms encompass interactions between MPs’ surface functional groups and biological tissues, alterations in oxidative stress markers, enzymatic activity and cytokine profiles, and modulation of gene expression patterns. This review synthesizes current knowledge on the ecological risks of freshwater MP pollution and its toxicological impacts on zebrafish, thereby providing a comprehensive framework for understanding MP toxicity mechanisms.
期刊：
Journal of Environmental Radioactivity,2025年285:107675 ISSN：0265-931X
通讯作者：
Xie, D
作者机构：
[Chen, Yuan-Chao] Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Peoples R China.;[Xie, D; Chen, Guo-Jie; Xie, Dong; Jia, Qian-Ran; Zeng, Jun; Yang, Yang] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Chen, Guo-Jie; Xie, Dong; Jia, Qian-Ran; Zeng, Jun; Chen, Yuan-Chao; Yang, Yang] Univ South China, Natl & Local Joint Engn Res Ctr Airborne Pollutant, Hengyang 421001, Peoples R China.
通讯机构：
[Xie, D ] U;Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
关键词：
Building wall;Coupled heat;Moisture and air transfer;Radon exhalation rate
摘要：
Building materials are one of the main sources of indoor radon, study of radon exhalation from building walls is of great reference significance for indoor radiation protection. Radon exhalation from building walls is comprehensively affected by environmental factors. A radon migration and exhalation model of building walls under the influence of coupled heat-moisture-air transfer was established. The radon exhalation mechanism of an aerated concrete wall under the influence of different relative humidity, temperature, relative humidity difference, temperature difference, air pressure difference and solar radiation was studied. The sensitivity of these factors to radon exhalation rate was analyzed. The results showed that the radon exhalation rate was positively correlated with relative humidity, but not with temperature; The radon exhalation rate was positively correlated with the relative humidity difference, and the temperature affected the correlation degree; The radon exhalation rate was positively correlated with the absolute temperature difference, and the relative humidity affected the correlation degree; The exhalation rate of radon was approximately linearly positive correlated with the pressure difference; Under the influence of solar radiation, the radon exhalation rate decreased; Radon parameters of material, relative humidity and solar radiation were more sensitive to radon exhalation rate than temperature, air pressure and radon concentration in air. For reducing radon exhalation rate of building walls and indoor radon concentration, we propose to use building wall materials with low radium content, keep indoor relative humidity and indoor and outdoor temperature difference low, and strengthen indoor ventilation at night, cloudy and rainy days.
Building materials are one of the main sources of indoor radon, study of radon exhalation from building walls is of great reference significance for indoor radiation protection. Radon exhalation from building walls is comprehensively affected by environmental factors. A radon migration and exhalation model of building walls under the influence of coupled heat-moisture-air transfer was established. The radon exhalation mechanism of an aerated concrete wall under the influence of different relative humidity, temperature, relative humidity difference, temperature difference, air pressure difference and solar radiation was studied. The sensitivity of these factors to radon exhalation rate was analyzed. The results showed that the radon exhalation rate was positively correlated with relative humidity, but not with temperature; The radon exhalation rate was positively correlated with the relative humidity difference, and the temperature affected the correlation degree; The radon exhalation rate was positively correlated with the absolute temperature difference, and the relative humidity affected the correlation degree; The exhalation rate of radon was approximately linearly positive correlated with the pressure difference; Under the influence of solar radiation, the radon exhalation rate decreased; Radon parameters of material, relative humidity and solar radiation were more sensitive to radon exhalation rate than temperature, air pressure and radon concentration in air. For reducing radon exhalation rate of building walls and indoor radon concentration, we propose to use building wall materials with low radium content, keep indoor relative humidity and indoor and outdoor temperature difference low, and strengthen indoor ventilation at night, cloudy and rainy days.
摘要：
Sludge is one of the primary reservoirs of microplastics (MPs), and the effects of MPs on subsequent sludge treatment raised attention. Given the entry pathways, MPs would exhibit different properties, but the entry pathway-dependent effect of MPs on sludge treatment performance and the fates of antibiotic resistance genes (ARGs), another high-risk emerging contaminant , were seldom documented. Herein, MPs with two predominant entry pathways, including wastewater-derived (WW-derived) and anaerobic digestion-introduced (AD-introduced), were used to investigate the effects on AD performance and ARGs abundances. The results indicated that WW-derived MPs, namely the MPs accumulated in sludge during the wastewater treatment process, exhibited significant inhibition on methane production by 22.8%–71.6%, while the AD-introduced MPs, being introduced in the sludge AD process, slightly increased the methane yield by 4.7%–17.1%. Meanwhile, MPs were responsible for promoting transmission of target ARGs, and polyethylene terephthalate MPs (PET-MPs) showed a greater promotion effect (0.0154–0.0936) than polyamide MPs (PA-MPs) (0.0013–0.0724). Compared to size, entry pathways and types played more vital roles on MPs influences. Investigation on mechanisms based on microbial community structure revealed characteristics (aging degree and types) of MPs determined the differences of AD performance and ARGs fates. WW-derived MPs with longer aging period and higher aging degree would release toxics and decrease the activities of microorganisms , resulting in the negative impact on AD performance. However, AD-introduced MPs with short aging period exhibited marginal impacts on AD performance. Furthermore, the co-occurrent network analysis suggested that the variations of potential host bacteria induced by MPs with different types and aging degree attributed to the dissemination of ARGs. Distinctively from most previous studies, the MPs with different sizes did not show remarkable effects on AD performance and ARGs fates. Our findings benefited the understanding of realistic environmental behavior and effect of MPs with different sources.
Sludge is one of the primary reservoirs of microplastics (MPs), and the effects of MPs on subsequent sludge treatment raised attention. Given the entry pathways, MPs would exhibit different properties, but the entry pathway-dependent effect of MPs on sludge treatment performance and the fates of antibiotic resistance genes (ARGs), another high-risk emerging contaminant , were seldom documented. Herein, MPs with two predominant entry pathways, including wastewater-derived (WW-derived) and anaerobic digestion-introduced (AD-introduced), were used to investigate the effects on AD performance and ARGs abundances. The results indicated that WW-derived MPs, namely the MPs accumulated in sludge during the wastewater treatment process, exhibited significant inhibition on methane production by 22.8%–71.6%, while the AD-introduced MPs, being introduced in the sludge AD process, slightly increased the methane yield by 4.7%–17.1%. Meanwhile, MPs were responsible for promoting transmission of target ARGs, and polyethylene terephthalate MPs (PET-MPs) showed a greater promotion effect (0.0154–0.0936) than polyamide MPs (PA-MPs) (0.0013–0.0724). Compared to size, entry pathways and types played more vital roles on MPs influences. Investigation on mechanisms based on microbial community structure revealed characteristics (aging degree and types) of MPs determined the differences of AD performance and ARGs fates. WW-derived MPs with longer aging period and higher aging degree would release toxics and decrease the activities of microorganisms , resulting in the negative impact on AD performance. However, AD-introduced MPs with short aging period exhibited marginal impacts on AD performance. Furthermore, the co-occurrent network analysis suggested that the variations of potential host bacteria induced by MPs with different types and aging degree attributed to the dissemination of ARGs. Distinctively from most previous studies, the MPs with different sizes did not show remarkable effects on AD performance and ARGs fates. Our findings benefited the understanding of realistic environmental behavior and effect of MPs with different sources.
作者机构：
[高媛媛; 周帅] Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang 421001, China;[周帅; 陈安琪; 李伦福; 杨锋娟; 黄啊潮; 黄泽枫] School of Civil Engineering, University of South China, Hengyang 421001, China;[高媛媛; 周帅] Hunan Province Key Laboratory of Rare Metal Mineral Exploitation and Geological Disposal of Wastes, Hengyang 421001, China;[修斐晨] Institute of Pathogenic Biology, Hengyang Medical College, University of South China, Hengyang 421001, China
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：
The emergence of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB) in the environment is well established as a human health crisis. The impact of radioactive heavy metals on ecosystems and ultimately on human health has become a global issue, especially for the regions suffering various nuclear activities or accidents. However, whether the radionuclides can affect the fate of antibiotic resistance in bacteria remains poorly understood. Here, the dynamics of ARB, three forms of ARGs-intracellular ARGs (iARGs), adsorbed extracellular ARGs (aeARGs), and free extracellular ARGs (feARGs)-and microbial communities were investigated following exposure to uranium (U), a representative radioactive heavy metal. The results showed that 90-d of U exposure at environmentally relevant concentrations of 0.05mg/L or 5mg/L significantly increased the ARB concentration in activated sludge (p<0.05). Furthermore, 90-d of U exposure slightly elevated the absolute abundance of aeARGs (except tetO) and sulfonamide iARGs, but decreased tetracycline iARGs. Regarding feARGs, the abundance of tetC, tetO, and sul1 decreased after 90-d of U stress, whereas sul2 showed the opposite trend. Partial least-squares path model analysis revealed that the abundance of aeARGs and iARGs under U stress was predominantly driven by increased cell membrane permeability/intI1 abundance and cell membrane permeability/reactive oxygen species concentration, respectively. Conversely, the changes in feARGs abundance depended on the composition of the microbial community and the expression of efflux pumps. Our findings shed light on the variations of ARGs and ARB in activated sludge under U exposure, providing a more comprehensive understanding of antibiotic resistance risks aggravated by radioactive heavy metal-containing wastewater.
摘要：
Levels of cadmium (Cd) and lead (Pb) correspond to common composition in acid mine wastewater of Hunan Province of China. The removal path of Cd and Pb and the structure of microbial community were investigated by developing constructed wetlands (CWs) with different layer positions of biochar. The biochar as a layer at the bottom of CW (BCW) system exhibited maximum Cd and Pb removal efficiencies of 96.6-98.6% and 97.2-98.9%, respectively. Compared with original soil, BCW increased the relative proportions of Proteobacteria, Firmicutes, Acidobacteriota, Verrucomicrobiota, Desulfobacterota, Armatimonadota, Bacteroidota, Patescibacteria, Basidiomycota (phylum level) and Burkholderia-Caballeronia-Paraburkholderia, Citrifermentans, Chthonomonadales, Cellulomonas, Geothrix, Terracidiphilus, Gallionellaceae, Microbacterium, Vanrija, Apiotrichum, Saitozyma, Fusarium (genus level). The concentrations of Cd and Pb were positively correlated with the abundance of Verrucomicrobiota, Basidiomycota (phylum level), and Methylacidiphilaceae, Meyerozyma, Vanrija (genus level). This study demonstrates that BCW system can improve removal performance toward Cd and Pb, as well as alter microbial community.
作者：
Su, Chi;Hua, Yilong;Liu, Yi;Tao, Shu;Jia, Fei;...
期刊：
PLOS ONE,2024年19(3):e0300800 ISSN：1932-6203
通讯作者：
Lin, WY
作者机构：
[Hua, Yilong; Liu, Yi; Su, Chi; Zhao, Wenhui] Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Peoples R China.;[Tao, Shu] Univ South China, Sch Math & Phys, Hengyang, Peoples R China.;[Jia, Fei] Univ South China, Sch Civil Engn, Hengyang, Peoples R China.;[Zhao, Wenhui] Shanxi Prov Changzhi City Wuxiang Cty Jia Huo Town, Changzhi, Peoples R China.;[Lin, WY; Lin, Wangyang] Univ South China, Coll Mech Engn, Hengyang, Peoples R China.
通讯机构：
[Lin, WY ] U;Univ South China, Coll Mech Engn, Hengyang, Peoples R China.
摘要：
Mining wastewater with heavy metals poses a serious threat to the ecological environment. However, the acute single and combined ecological effects of heavy metals, such as chromium (Cr) and nickel (Ni), on freshwater ostracods, and the development of relevant prediction models, remain poorly understood. In this study, Heterocypris sp. was chosen to investigate the single and combined acute toxicity of Cr and Ni. Then, the quantitative structure-activity relationship (QSAR) model was used to predict the combined toxicity of Cr and Ni. The single acute toxicity experiments revealed high toxicity for both Cr and Ni. In addition, Cr exhibited greater toxicity compared to Ni, as evidenced by its lower 96-hour half-lethal concentration (LC50) of 1.07 mg/L compared to 4.7 mg/L for Ni. Furthermore, the combined acute toxicity experiments showed that the toxicity of Cr-Ni was higher than Ni but lower than Cr. Compared with the concentration addition (CA) and independent action (IA) models, the predicted results of the QSAR model were more consistent with the experimental results for the Cr-Ni combined acute toxicity. So, the high accuracy of QSAR model identified its feasibility to predict the toxicity of heavy metal pollutants in mining wastewater.
摘要：
Activated sludge is an important reservoir for the co-occurring emerging contaminants including nanoplastics (NPs) and antibiotic resistance genes (ARGs). However, the impacts and potential mechanisms of NPs on the fate of ARGs in activated sludge are not fully understood. Herein, we used metagenomic approach to investigate the responses of ARGs, host bacteria, mobile genetic elements (MGEs), and functional genes to polystyrene (PS) NPs at environmentally relevant (0.5 mg/L) and high stress concentrations (50 mg/L) in activated sludge. The results showed that 0.5 and 50 mg/L PS NPs increased the relative abundance of ARGs in the activated sludge by 58.68% and 46.52%, respectively ( p < 0.05). Host tracking analysis elucidated that the hosts of ARGs were significantly enriched by PS NPs ( p < 0.05), with Proteobacteria being the predominant host bacteria. Additionally, the occurrence of new ARGs hosts and the enrichment of MGEs and functional genes (i.e., genes related to SOS response, cell membrane permeability, and secretion system, etc.) indicated that PS NPs promoted horizontal gene transfer (HGT) of ARGs. Finally, path modeling analysis revealed that the proliferation of ARGs caused by PS NPs was primarily attributed to the enhancement of HGT and the enrichment of host bacteria. Our findings contribute to a comprehensive understanding of the spread risk of ARGs in activated sludge under NPs pollution.
Activated sludge is an important reservoir for the co-occurring emerging contaminants including nanoplastics (NPs) and antibiotic resistance genes (ARGs). However, the impacts and potential mechanisms of NPs on the fate of ARGs in activated sludge are not fully understood. Herein, we used metagenomic approach to investigate the responses of ARGs, host bacteria, mobile genetic elements (MGEs), and functional genes to polystyrene (PS) NPs at environmentally relevant (0.5 mg/L) and high stress concentrations (50 mg/L) in activated sludge. The results showed that 0.5 and 50 mg/L PS NPs increased the relative abundance of ARGs in the activated sludge by 58.68% and 46.52%, respectively ( p < 0.05). Host tracking analysis elucidated that the hosts of ARGs were significantly enriched by PS NPs ( p < 0.05), with Proteobacteria being the predominant host bacteria. Additionally, the occurrence of new ARGs hosts and the enrichment of MGEs and functional genes (i.e., genes related to SOS response, cell membrane permeability, and secretion system, etc.) indicated that PS NPs promoted horizontal gene transfer (HGT) of ARGs. Finally, path modeling analysis revealed that the proliferation of ARGs caused by PS NPs was primarily attributed to the enhancement of HGT and the enrichment of host bacteria. Our findings contribute to a comprehensive understanding of the spread risk of ARGs in activated sludge under NPs pollution.
摘要：
Transformation represents one of the most important pathways for the horizontal transfer of antibiotic resistance genes (ARGs), which enables competent bacteria to acquire extracellular ARGs from the surrounding environment. Both heavy metals and irradiation have been demonstrated to influence the bacterial transformation process. However, the impact of ubiquitously occurring radioactive heavy metals on the transformation of ARGs remains largely unknown. Here, we showed that a representative radioactive nuclide, uranium (U), at environmental concentrations (0.005-5mg/L), improved the transformation frequency of resistant plasmid pUC19 into Escherichia coli by 0.10-0.85-fold in a concentration-dependent manner. The enhanced ARGs transformation ability under U stress was demonstrated to be associated with reactive oxygen species (ROS) overproduction, membrane damage, and up-regulation of genes related to DNA uptake and recombination. Membrane permeability and ROS production were the predominant direct and indirect factors affecting transformation ability, respectively. Our findings provide valuable insight into the underlying mechanisms of the impacts of U on the ARGs transformation process and highlight concerns about the exacerbated spread of ARGs in radioactive heavy metal-contaminated ecosystems, especially in areas with nuclear activity or accidents.
摘要：
The reduction of soluble U(VI) to insoluble and less toxic U(IV) by photocatalysis is an effective method to control uranium contamination. The graphitic carbon nitride nanosheet (CNN)/UiO-66 composites (CNNU) were prepared by thermal polymerization and solvothermal methods for the removal of U(VI). The morphology, crystal structure and optical properties of composites were analyzed by SEM, XRD, BET, UV-DRS, PL and EIS. The results showed the introduction of UiO-66 increased the specific surface of CNN from 9.07 m(2)/g to 46.24 m(2)/g, and effectively suppressed the recombination of photogenerated electrons and holes and improved the photocatalytic activity. The U(VI) removal capacity by adsorption and photocatalysis of CNNU was reached 779.47mg/g, which significantly higher than that of adsorption (478.38mg/g). The adsorption process was found to conform to the pseudo-second-order kinetic model and the Langmuir isothermal model. Meanwhile, U(VI) adsorbed on the CNNU was reduced to U(IV) via e(-) and ·O(2)(-) generated in the photocatalytic process. Therefore, this outstanding performance of CNNU in U(VI) removal is attributed to the synergistic effect of adsorption and photocatalytic reduction.
摘要：
Antibiotic resistance genes (ARGs) in activated sludge include intracellular ARGs (iARGs) and extracellular ARGs (eARGs), both of which are recognized as emerging pollutants. While the activated sludge process has been commonly considered for treating wastewater contaminated with radionuclide, the effects and mechanisms of radioactive heavy metals on the fate of iARGs and eARGs (i/e-ARGs) in activated sludge are largely elusive. Here, the distribution, mobility, and hosts of i/e-ARGs in activated sludge during environmental concentrations (50 μg/L and 5000 μg/L) of radioactive uranium (U) stress were explored via metagenomics. The results revealed that the total relative abundance of iARGs and eARGs decreased by 11.62% and 10.41%, respectively, after 90 days of 50 μg/L of U treatment. In contrast, both i/e-multi- and tetracycline ARGs remarkably increased after being exposed to 5000 μg/L of U. Additionally, exposure to 5000 μg/L of U triggered notable decrease in i/e-insertion sequences and plasmids abundance, but significantly enriched i/e-integrons ( p < 0.05). Partial least squares pathway modelling indicated that the prevalence of iARGs and eARGs in activated sludge was primarily driven by bacterial hosts and functional genes, respectively. Our findings revealed the dichotomous variation landscape and mechanisms of i/e-ARGs dynamics in activated sludge during U exposure, offering valuable insights for controlling ARGs risk during radioactive wastewater treatment.
Antibiotic resistance genes (ARGs) in activated sludge include intracellular ARGs (iARGs) and extracellular ARGs (eARGs), both of which are recognized as emerging pollutants. While the activated sludge process has been commonly considered for treating wastewater contaminated with radionuclide, the effects and mechanisms of radioactive heavy metals on the fate of iARGs and eARGs (i/e-ARGs) in activated sludge are largely elusive. Here, the distribution, mobility, and hosts of i/e-ARGs in activated sludge during environmental concentrations (50 μg/L and 5000 μg/L) of radioactive uranium (U) stress were explored via metagenomics. The results revealed that the total relative abundance of iARGs and eARGs decreased by 11.62% and 10.41%, respectively, after 90 days of 50 μg/L of U treatment. In contrast, both i/e-multi- and tetracycline ARGs remarkably increased after being exposed to 5000 μg/L of U. Additionally, exposure to 5000 μg/L of U triggered notable decrease in i/e-insertion sequences and plasmids abundance, but significantly enriched i/e-integrons ( p < 0.05). Partial least squares pathway modelling indicated that the prevalence of iARGs and eARGs in activated sludge was primarily driven by bacterial hosts and functional genes, respectively. Our findings revealed the dichotomous variation landscape and mechanisms of i/e-ARGs dynamics in activated sludge during U exposure, offering valuable insights for controlling ARGs risk during radioactive wastewater treatment.
摘要：
Quorum sensing (QS) is prevalent in activated sludge processes; however, its essential role in the treatment of heavy metal wastewater has rarely been studied. Therefore, in this study, acyl homoserine lactone (AHL)-mediated QS was used to regulate the removal performance, enzyme activity , and microbial community of Cd- and Pb-containing wastewater in a sequencing batch reactor (SBR) over 30 cycles. The results showed that exogenous AHL strengthened the removal of Cd(II) and Pb(II) in their coexistence wastewater during the entire period. The removal of NH 4 + -N, total phosphorus, and chemical oxygen demand (COD) was also enhanced by the addition of AHL despite the coexistence of Cd(II) and Pb(II). Meanwhile, the protein content of extracellular polymeric substances was elevated and the microbial metabolism and antioxidative response were stimulated by the addition of AHL, which was beneficial for resistance to heavy metal stress and promoted pollutant removal by activated sludge . Microbial sequencing indicated that AHL optimized the microbial community structure, with the abundance of dominant taxa Proteobacteria and Unclassified_f_Enterobacteriaceae increasing by 73.9% and 59.2% maximally, respectively. This study offers valuable insights into the mechanisms underlying Cd(II) and Pb(II) removal as well as microbial community succession under AHL availability in industrial wastewater .
Quorum sensing (QS) is prevalent in activated sludge processes; however, its essential role in the treatment of heavy metal wastewater has rarely been studied. Therefore, in this study, acyl homoserine lactone (AHL)-mediated QS was used to regulate the removal performance, enzyme activity , and microbial community of Cd- and Pb-containing wastewater in a sequencing batch reactor (SBR) over 30 cycles. The results showed that exogenous AHL strengthened the removal of Cd(II) and Pb(II) in their coexistence wastewater during the entire period. The removal of NH 4 + -N, total phosphorus, and chemical oxygen demand (COD) was also enhanced by the addition of AHL despite the coexistence of Cd(II) and Pb(II). Meanwhile, the protein content of extracellular polymeric substances was elevated and the microbial metabolism and antioxidative response were stimulated by the addition of AHL, which was beneficial for resistance to heavy metal stress and promoted pollutant removal by activated sludge . Microbial sequencing indicated that AHL optimized the microbial community structure, with the abundance of dominant taxa Proteobacteria and Unclassified_f_Enterobacteriaceae increasing by 73.9% and 59.2% maximally, respectively. This study offers valuable insights into the mechanisms underlying Cd(II) and Pb(II) removal as well as microbial community succession under AHL availability in industrial wastewater .
摘要：
In this study, we investigated the effect of detoxifying substances on U(VI) removal by bacteria isolated from mine soil. The results demonstrated that the highest U(VI) removal efficiency (85.6%) was achieved at pH 6.0 and a temperature of 35 °C, with an initial U(VI) concentration of 10 mg/L. For detoxifying substances, signaling molecules acyl homoserine lactone (AHLs, 0.1 µmol/L), anthraquinone-2, 6-disulfonic acid (AQDS, 1 mmol/L), reduced glutathione (GSH, 0.1 mmol/L), selenium (Se, 1 mg/L), montmorillonite (MT, 1 g/L), and ethylenediaminetetraacetic acid (EDTA, 0.1 mmol/L) substantially enhanced the bacterial U(VI) removal by 34.9%, 37.4%, 54.5%, 35.1%, 32.8%, and 47.8% after 12 h, respectively. This was due to the alleviation of U(VI) toxicity in bacteria through detoxifying substances, as evidenced by lower malondialdehyde (MDA) content and higher superoxide dismutase (SOD) and catalase (CAT) activities for bacteria exposed to U(VI) and detoxifying substances, compared to those exposed to U(VI) alone. FTIR results showed that hydroxyl, carboxyl, phosphorus, and amide groups participated in the U(VI) removal. After exposure to U(VI), the relative abundances of Chryseobacterium and Stenotrophomonas increased by 48.5% and 12.5%, respectively, suggesting their tolerance ability to U(VI). Gene function prediction further demonstrated that the detoxifying substances AHLs alleviate U(VI) toxicity by influencing bacterial metabolism. This study suggests the potential application of detoxifying substances in the U(VI)-containing wastewater treatment through bioremediation.
作者机构：
[Zhou, Shuai; Wang, Yayi; Zhang, Yalei] Tongji Univ, Coll Environm Sci & Engn, State Key Lab Pollut Control & Resources Reuse, Siping Rd, Shanghai 200092, Peoples R China.;[Zhou, Shuai; Zhang, Siqi; Duan, Yi; Yang, Zhengqing] Univ South China, Sch Civil Engn, Hunan Prov Key Lab Pollut Control & Resources Reus, Hengyang 421001, Peoples R China.;[Gao, Yuanyuan; Tang, Zhenping] Univ South China, Hunan Prov Key Lab Rare Met Minerals Exploitat & G, Hengyang 421001, Peoples R China.
通讯机构：
[Wang, YY ] T;Tongji Univ, Coll Environm Sci & Engn, State Key Lab Pollut Control & Resources Reuse, Siping Rd, Shanghai 200092, Peoples R China.
关键词：
Activated sludge;Environmental condition;Extracellular antibiotic resistance genes;Metagenomics;Starvation;Substrate type
摘要：
Extracellular antibiotic resistance genes (eARGs) are important emerging environmental pollutants in wastewater treatment plants (WWTPs). Nutritional substrate deficiency (i.e., starvation) frequently occurs in WWTPs owing to annual maintenance, water quality fluctuation, and sludge storage; and it can greatly alter the antibiotic resistance and extracellular DNA content of bacteria. However, the fate and corresponding transmission risk of eARGs in activated sludge under starvation stress remain largely unknown. Herein, we used metagenomic sequencing to explore the effects of starvation scenarios (carbon, nitrogen, and/or phosphorus deficiency) and environmental conditions (alternating anaerobic-aerobic, anaerobic, anoxic, and aerobic) on the distribution, mobility, and hosts of eARGs in activated sludge. The results showed that 30 days of starvation reduced the absolute abundances of eARGs by 40.9%-88.2%, but high-risk dual and multidrug resistance genes persisted. Starvation, particularly the simultaneous lack of carbon, nitrogen, and phosphorus under aerobic conditions, effectively alleviated eARGs by reducing the abundance of extracellular mobile genetic elements (eMGEs). Starvation also altered the profile of bacterial hosts of eARGs and the bacterial community composition, the latter of which had an indirect positive effect on eARGs via changing eMGEs. Our findings shed light on the response patterns and mechanisms of eARGs in activated sludge under starvation conditions and highlight starvation as a potential strategy to mitigate the risk of previously neglected eARGs in WWTPs.
摘要：
Electrocatalytic oxidation is commonly restricted by low degradation efficiency, slow mass transfer, and high energy consumption. Herein, a synergetic electrocatalysis system was developed for removal of various drugs, i.e., atenolol, florfenicol, and diclofenac sodium, as well as actual pharmaceutical wastewater, where the newly-designed single-atom Zr embedded Ti4O7 (Zr/Ti4O7) and hierarchical CuFe2O4 (CFO) microspheres were used as anode and microelectrodes, respectively. In the optimal reaction system, the degradation efficiencies of 40 mg L–1 atenolol, florfenicol, and diclofenac sodium could achieve up to 98.8%, 93.4%, and 85.5% in 120 min with 0.1 g L–1 CFO at current density of 25 mA cm–2. More importantly, in the flow-through reactor, the electrooxidation lasting for 150 min could reduce the COD of actual pharmaceutical wastewater from 432 to 88.6 mg L−1, with a lower energy consumption (25.67 kWh/m3). Meanwhile, the electrooxidation system maintained superior stability and environmental adaptability. DFT theory calculations revealed that the excellent performance of this electrooxidation system could be ascribed to the striking features of the reduced reaction energy barrier by single-atom Zr loading and abundant oxygen vacancies on the Zr/Ti4O7 surface. Moreover, the characterization and experimental results demonstrated that the CFO unique hierarchical structure and synergistic effect between electrodes were also the important factors that could improve the system performance. The findings shed light on the single-atom material design for boosting electrochemical oxidation performance.
Electrocatalytic oxidation is commonly restricted by low degradation efficiency, slow mass transfer, and high energy consumption. Herein, a synergetic electrocatalysis system was developed for removal of various drugs, i.e., atenolol, florfenicol, and diclofenac sodium, as well as actual pharmaceutical wastewater, where the newly-designed single-atom Zr embedded Ti4O7 (Zr/Ti4O7) and hierarchical CuFe2O4 (CFO) microspheres were used as anode and microelectrodes, respectively. In the optimal reaction system, the degradation efficiencies of 40 mg L–1 atenolol, florfenicol, and diclofenac sodium could achieve up to 98.8%, 93.4%, and 85.5% in 120 min with 0.1 g L–1 CFO at current density of 25 mA cm–2. More importantly, in the flow-through reactor, the electrooxidation lasting for 150 min could reduce the COD of actual pharmaceutical wastewater from 432 to 88.6 mg L−1, with a lower energy consumption (25.67 kWh/m3). Meanwhile, the electrooxidation system maintained superior stability and environmental adaptability. DFT theory calculations revealed that the excellent performance of this electrooxidation system could be ascribed to the striking features of the reduced reaction energy barrier by single-atom Zr loading and abundant oxygen vacancies on the Zr/Ti4O7 surface. Moreover, the characterization and experimental results demonstrated that the CFO unique hierarchical structure and synergistic effect between electrodes were also the important factors that could improve the system performance. The findings shed light on the single-atom material design for boosting electrochemical oxidation performance.
通讯机构：
[Taotao Zeng] H;Hunan Province Key Laboratory of Pollution Control and Resources Reuse Technology, University of South China, Hengyang, 421001, Hunan, China
摘要：
The use of modified biochar for the remediation of heavy metal (HM) has received much attention. However, the immobilization mechanism of biochar to multiple HMs and the interaction of different forms of HMs with microorganisms are still unclear. K(2)HPO(4)-modified biochar (PBC) was produced and used in a 90-days immobilization experiment with soil collected from a typic lead-zinc (Pb-Zn) mining soil. Incubation experiments showed that PBC enhanced the transformation of Cd, Pb, Zn and Cu from exchangeable (Ex-) and/or carbonate-bound forms (Car-) to organic matter-bound (Or-) and/or residual forms (Re-). After scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDS), X-ray diffractometry (XRD), fourier transform infrared (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) analysis, the mechanisms of HM immobilization by PBC were proposed as precipitation (PO(4)(3-), HPO(4)(2-), OH(-) and CO(3)(2-)), electrostatic attraction, complexation (-COOH, -OH and R-O-H) and the indirect roles of soil parameter variations (pH, moisture and microbial community). Microbial community analysis through high-throughput sequencing showed that PBC reduced bacterial and fungal abundance. However, addition of PBC increased the relative proportions of Proteobacteria by 15.04%-42.99%, Actinobacteria by 4.74%-22.04%, Firmicutes by 0.76%-23.35%, Bacteroidota by 0.16%-12.34%, Mortierellomycota by 4.00%-9.66% and Chytridiomycota by 0.10%-13.7%. Ex-Cd/Pb/Zn, Car-Cd/Zn and Re-Cd/Pb/As were significantly positively (0.001<P≤0.05) correlated with bacterial phyla of Crenarchaeota and Methylomirabilota, and Re-Cu and Ex-/Car-/Fe-Mn oxide-bound (Fe-Mn-)/Or-As were significantly positively correlated (0.001<P≤0.05) with the bacterial phyla of Proteobacteria and Bacteroidota. While Car-Cd/Zn and Re-Pb/As were positively correlated (0.01<P≤0.05) with fungal phyla of Ascomycota, Glomeromycota, Kickxellomycota, Basidiomycota and Mucoromycota. The bacterial network contained more complex interactions than the fungal network, suggesting that bacteria play a larger role in HMs transformation processes. The results indicate that PBC is an effective agent for the remediation of HMs polluted soil in Pb-Zn mining areas.
