Identifying hydrochemical processes in groundwater systems is a critical prerequisite for implementing pollution abatement in high-sulfur nonferrous metal mining areas. However, the sulfate sources and evolution mechanisms remain unclear due to complex hydrogeological conditions and intense anthropogenic disturbances. This study combines self-organizing maps (SOM), MixSIAR modeling, hydrochemical analysis, and multi-isotope tracers to clarify the sources and evolution of sulfate in groundwater from the Tianmashan sulfur-gold mining area. Results reveal a distinct depth-dependent pattern: shallow aquifers are dominated by sulfate derived from skarn sulfide oxidation (e.g., pyrite), enhanced by Fe3+ transport from adjacent closed mines and mining-induced fractures. In contrast, deep aquifers, characterized by sluggish flow and limited connectivity, are governed by gypsum dissolution and cation exchange, with minor contributions from atmospheric precipitation via vertical shafts. A conceptual model highlights the roles of intermine hydraulic connectivity and redox zonation in controlling sulfate evolution. These findings provide a scientific basis for targeted acid mine drainage (AMD) management, advocating a "contain the shallow, utilize the deep" strategy for sustainable groundwater remediation.
{"title":"Geochemical and Isotopic Fingerprint-Based Identification of Sulfate Source Regional Characteristics and Evolution of Groundwater Impacted by Acid Mine Drainage (AMD) from a Nonferrous Metal Mining Area.","authors":"Bing Wang,Lei Ma,Jiazhong Qian,Yunhai Fang,Wei Xie,Dan Ding,Yang Long,Huan Zhou","doi":"10.1021/acs.est.5c09899","DOIUrl":"https://doi.org/10.1021/acs.est.5c09899","url":null,"abstract":"Identifying hydrochemical processes in groundwater systems is a critical prerequisite for implementing pollution abatement in high-sulfur nonferrous metal mining areas. However, the sulfate sources and evolution mechanisms remain unclear due to complex hydrogeological conditions and intense anthropogenic disturbances. This study combines self-organizing maps (SOM), MixSIAR modeling, hydrochemical analysis, and multi-isotope tracers to clarify the sources and evolution of sulfate in groundwater from the Tianmashan sulfur-gold mining area. Results reveal a distinct depth-dependent pattern: shallow aquifers are dominated by sulfate derived from skarn sulfide oxidation (e.g., pyrite), enhanced by Fe3+ transport from adjacent closed mines and mining-induced fractures. In contrast, deep aquifers, characterized by sluggish flow and limited connectivity, are governed by gypsum dissolution and cation exchange, with minor contributions from atmospheric precipitation via vertical shafts. A conceptual model highlights the roles of intermine hydraulic connectivity and redox zonation in controlling sulfate evolution. These findings provide a scientific basis for targeted acid mine drainage (AMD) management, advocating a \"contain the shallow, utilize the deep\" strategy for sustainable groundwater remediation.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"44 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145752497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yihui Zhang,Jinge Zhu,Weiping Hu,Zhaoliang Peng,Hui Chen,Jiancai Deng,Jing Luo,Jian Yang
Based on zonal management and engineering-ecological synergy, this study innovatively designed and constructed a "pollution absorption zone" (PAZ) system to restore shallow eutrophic lakes, in response to excessive external nitrogen and phosphorus loads and the degradation of aquatic vegetation. Using Lake Changdanghu (China's Yangtze River Basin) as a case study, a functionally synergistic PAZ integrating underwater shoals, bottom traps, prereservoirs, and flow-guiding channels was constructed. Three-year monitoring demonstrated that PAZ effectively attenuated wind wave by 72% via the underwater shoals, significantly reducing the concentration of suspended solids and increasing water transparency. The marked increase in transparency has successfully created a still, clear-water environment conducive to the recovery of aquatic vegetation. Simultaneously, the synergistic effect of the PAZ effectively intercepted and slowed polluted inflows, thereby creating favorable conditions for in situ pollutant purification. With the improved habitat conditions, the area, distribution range, biomass, and coverage of aquatic vegetation within the PAZ have all significantly increased, leading to the effective restoration of the ecosystem structure. These outcomes demonstrate PAZ effectively mitigate external nitrogen, phosphorus loads while restoring degraded habitats. This study provides a replicable, large-scale engineering solution for balancing environmental carrying capacity with nutrient pressure through coupled physical-ecological intervention.
{"title":"Restoring Shallow Lakes by Constructing Pollution Absorption Zone: Practices and Insights.","authors":"Yihui Zhang,Jinge Zhu,Weiping Hu,Zhaoliang Peng,Hui Chen,Jiancai Deng,Jing Luo,Jian Yang","doi":"10.1021/acs.est.5c06249","DOIUrl":"https://doi.org/10.1021/acs.est.5c06249","url":null,"abstract":"Based on zonal management and engineering-ecological synergy, this study innovatively designed and constructed a \"pollution absorption zone\" (PAZ) system to restore shallow eutrophic lakes, in response to excessive external nitrogen and phosphorus loads and the degradation of aquatic vegetation. Using Lake Changdanghu (China's Yangtze River Basin) as a case study, a functionally synergistic PAZ integrating underwater shoals, bottom traps, prereservoirs, and flow-guiding channels was constructed. Three-year monitoring demonstrated that PAZ effectively attenuated wind wave by 72% via the underwater shoals, significantly reducing the concentration of suspended solids and increasing water transparency. The marked increase in transparency has successfully created a still, clear-water environment conducive to the recovery of aquatic vegetation. Simultaneously, the synergistic effect of the PAZ effectively intercepted and slowed polluted inflows, thereby creating favorable conditions for in situ pollutant purification. With the improved habitat conditions, the area, distribution range, biomass, and coverage of aquatic vegetation within the PAZ have all significantly increased, leading to the effective restoration of the ecosystem structure. These outcomes demonstrate PAZ effectively mitigate external nitrogen, phosphorus loads while restoring degraded habitats. This study provides a replicable, large-scale engineering solution for balancing environmental carrying capacity with nutrient pressure through coupled physical-ecological intervention.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"1 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145752490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sponges (Porifera) are among the oldest known animal-microbe symbioses and are key players in marine biogeochemical cycles. Ubiquitous across benthic marine habitats, they process dissolved organic matter and participate in chemosynthetic pathways. We quantified, for the first time, volatile organic compounds (VOCs, namely, halomethanes, sulfur-containing compounds, and isoprene) in the inhaled and exhaled water of three Mediterranean sponge species: two high-microbial abundance (HMA), Aplysina aerophoba and Agelas oroides, and one low-microbial abundance (LMA), Dysidea avara. Using the Vacusip-INEX method in aquaria and in situ in a NW Mediterranean marine-protected area, we found that HMA sponges efficiently removed bromomethanes and dimethyl disulfide (DMS) and less clearly iodomethanes, carbon disulfide (CS2), and isoprene, while the LMA species removed methyl iodide (CH3I), DMS, and isoprene depending on the ambient seawater concentration. In preliminary experiments with A. aerophoba specimens, chemical inhibition of nitrification (with nitrapyrin) arrested bromomethane, DMS removal, and nitrate production, consistent with co-metabolic consumption by endosymbiotic nitrifying bacteria. Sponge VOC removal rates exceeded those of bacterioplankton by orders of magnitude. These findings underscore sponges as major sinks for VOCs in sponge-rich littoral ecosystems, with potential for bioremediation and mitigation of coastal VOC emissions, and call for further research into the ecological implications, impact on coastal air quality, and contributions to elemental cycling.
{"title":"Removal of Volatile Organic Compounds by Marine Sponges: Implications for Coastal Bioremediation.","authors":"Rafel Simó,Rafel Coma,Pau Cortés-Greus,Marta Masdeu-Navarro,Teresa Morganti,Marta Ribes","doi":"10.1021/acs.est.5c05458","DOIUrl":"https://doi.org/10.1021/acs.est.5c05458","url":null,"abstract":"Sponges (Porifera) are among the oldest known animal-microbe symbioses and are key players in marine biogeochemical cycles. Ubiquitous across benthic marine habitats, they process dissolved organic matter and participate in chemosynthetic pathways. We quantified, for the first time, volatile organic compounds (VOCs, namely, halomethanes, sulfur-containing compounds, and isoprene) in the inhaled and exhaled water of three Mediterranean sponge species: two high-microbial abundance (HMA), Aplysina aerophoba and Agelas oroides, and one low-microbial abundance (LMA), Dysidea avara. Using the Vacusip-INEX method in aquaria and in situ in a NW Mediterranean marine-protected area, we found that HMA sponges efficiently removed bromomethanes and dimethyl disulfide (DMS) and less clearly iodomethanes, carbon disulfide (CS2), and isoprene, while the LMA species removed methyl iodide (CH3I), DMS, and isoprene depending on the ambient seawater concentration. In preliminary experiments with A. aerophoba specimens, chemical inhibition of nitrification (with nitrapyrin) arrested bromomethane, DMS removal, and nitrate production, consistent with co-metabolic consumption by endosymbiotic nitrifying bacteria. Sponge VOC removal rates exceeded those of bacterioplankton by orders of magnitude. These findings underscore sponges as major sinks for VOCs in sponge-rich littoral ecosystems, with potential for bioremediation and mitigation of coastal VOC emissions, and call for further research into the ecological implications, impact on coastal air quality, and contributions to elemental cycling.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"156 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145759885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mineral-associated organic matter involving iron oxyhydroxide minerals is important to the preservation and transformation of organic matter in soils and sediments. Largely lacking is a quantitative evaluation of different binding mechanisms in relation to the mineral surface charges. Here, with ferrihydrite, we investigated complexes with organic compounds of various charges and structures, including a ribonucleotide, a sugar, a phenolic acid, and amino acids with different side chains. After constructing model ferrihydrite nanoparticles using reported iron-oxygen coordination, we mapped theoretically the spatial distribution of positive and negative charges, corroborated experimentally by atomic force microscopy. With these variable charges due to protonation extent of surface hydroxyls, molecular dynamics simulations revealed binding mechanisms of organic moieties with opposite charges, confirmed experimentally by infrared spectroscopy. For electrostatic interactions, quantum mechanics-calculated energies determined the order of binding strength consistent with our adsorption data: ester-linked phosphate > protonated primary amine ≥ carboxylate attached to phenyl ring = carboxylate attached to alkyl group. Ligand exchange, which was more thermodynamically favorable than electrostatic interactions despite the energy barrier to the transition state, was driven by the stability of the product. We obtained a quantitative rationale for the binding of ribonucleotide phosphate through ligand exchange versus binding of carboxylate and amino groups through electrostatic interactions, thus informing mechanistic frameworks for mineral-organic associations.
{"title":"Surface Charge Heterogeneity and Mechanisms of Organic Binding Modes on an Iron Oxyhydroxide.","authors":"Jiaxing Wang,Benjamin Barrios-Cerda,Ludmilla Aristilde","doi":"10.1021/acs.est.5c10850","DOIUrl":"https://doi.org/10.1021/acs.est.5c10850","url":null,"abstract":"Mineral-associated organic matter involving iron oxyhydroxide minerals is important to the preservation and transformation of organic matter in soils and sediments. Largely lacking is a quantitative evaluation of different binding mechanisms in relation to the mineral surface charges. Here, with ferrihydrite, we investigated complexes with organic compounds of various charges and structures, including a ribonucleotide, a sugar, a phenolic acid, and amino acids with different side chains. After constructing model ferrihydrite nanoparticles using reported iron-oxygen coordination, we mapped theoretically the spatial distribution of positive and negative charges, corroborated experimentally by atomic force microscopy. With these variable charges due to protonation extent of surface hydroxyls, molecular dynamics simulations revealed binding mechanisms of organic moieties with opposite charges, confirmed experimentally by infrared spectroscopy. For electrostatic interactions, quantum mechanics-calculated energies determined the order of binding strength consistent with our adsorption data: ester-linked phosphate > protonated primary amine ≥ carboxylate attached to phenyl ring = carboxylate attached to alkyl group. Ligand exchange, which was more thermodynamically favorable than electrostatic interactions despite the energy barrier to the transition state, was driven by the stability of the product. We obtained a quantitative rationale for the binding of ribonucleotide phosphate through ligand exchange versus binding of carboxylate and amino groups through electrostatic interactions, thus informing mechanistic frameworks for mineral-organic associations.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"68 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145752494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Past studies have found that carbon reduction strategies generally reduce emissions of nitrogen oxides (NOX) and/or volatile organic compounds (VOCs). The reverse is not true, however, as evidenced by over 50 years of air quality improvements in the U.S. with only modest reductions of carbon dioxide (CO2) emissions. This analysis compares energy and emissions pathways to achieve NOX and VOCs targets calculated by the U.S. Environmental Protection Agency (EPA) to meet a hypothetical 65 ppb revision to the National Ambient Air Quality Standard (NAAQS) for ozone. To meet these targets, we model sector-specific reductions over a 15-year horizon with the Multipollutant Emissions Calculator for Air Quality and Climate (MECAQC), considering both conventional emission controls, e.g. technologies, as well as energy system changes, e.g., fuel-switching. Switching away from conventional fuels can achieve the majority of required NOX and VOCs emission reductions, considering maximum decarbonization up to 45% for heavy-duty vehicles, up to 65% for light-duty vehicles, up to 36% for building electrification, and up to 100% for electricity generation. The maximum decarbonization assumptions alone could meet NOX and VOCs targets in the Midwest region and VOCs targets in the Northeast region, reducing NOX emissions in affected areas by 44%, VOCs by 16%, and CO2 by 56%. These carbon-reduction strategies may be supplemented by conventional emission controls to achieve additional VOCs reductions to meet the most targets: reducing NOX emissions in affected areas by 33%, VOCs by 17%, and CO2 by 35%. Conventional controls alone could meet all regional targets except the California NOX target, which cannot be met by any approach evaluated here, reducing NOx emissions in affected areas by 33% and VOCs by 17%, but increasing emissions of CO2 by 1.4%.
{"title":"Emissions Reductions to Meet a Tighter Ozone Standard in the U.S. through Control Technologies versus Clean Energy Transition Scenarios.","authors":"Paul Meier,Tracey Holloway,Xinran Wu,Cecilia Orth","doi":"10.1021/acs.est.5c01588","DOIUrl":"https://doi.org/10.1021/acs.est.5c01588","url":null,"abstract":"Past studies have found that carbon reduction strategies generally reduce emissions of nitrogen oxides (NOX) and/or volatile organic compounds (VOCs). The reverse is not true, however, as evidenced by over 50 years of air quality improvements in the U.S. with only modest reductions of carbon dioxide (CO2) emissions. This analysis compares energy and emissions pathways to achieve NOX and VOCs targets calculated by the U.S. Environmental Protection Agency (EPA) to meet a hypothetical 65 ppb revision to the National Ambient Air Quality Standard (NAAQS) for ozone. To meet these targets, we model sector-specific reductions over a 15-year horizon with the Multipollutant Emissions Calculator for Air Quality and Climate (MECAQC), considering both conventional emission controls, e.g. technologies, as well as energy system changes, e.g., fuel-switching. Switching away from conventional fuels can achieve the majority of required NOX and VOCs emission reductions, considering maximum decarbonization up to 45% for heavy-duty vehicles, up to 65% for light-duty vehicles, up to 36% for building electrification, and up to 100% for electricity generation. The maximum decarbonization assumptions alone could meet NOX and VOCs targets in the Midwest region and VOCs targets in the Northeast region, reducing NOX emissions in affected areas by 44%, VOCs by 16%, and CO2 by 56%. These carbon-reduction strategies may be supplemented by conventional emission controls to achieve additional VOCs reductions to meet the most targets: reducing NOX emissions in affected areas by 33%, VOCs by 17%, and CO2 by 35%. Conventional controls alone could meet all regional targets except the California NOX target, which cannot be met by any approach evaluated here, reducing NOx emissions in affected areas by 33% and VOCs by 17%, but increasing emissions of CO2 by 1.4%.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"166 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145752710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Enhanced rock weathering (ERW) is a promising CO2 removal (CDR) strategy that aims to accelerate the natural process of silicate weathering to increase soil pore water alkalinity and sequester CO2. However, the measurement, reporting, and verification (MRV) of ERW remains challenging due to existing limitations of aqueous-phase sampling methodologies, such as passive and tension lysimeters, which may not fully capture weathering fluxes across varying soil moisture conditions. This study assesses the potential of a centrifugation-based pore water extraction method to improve the accuracy and reliability of ERW measurements. Using a forest ERW trial in Wales, UK, we compared the chemistry of soil pore waters obtained via lysimeters and centrifugation from feedstock-amended and control plots. The centrifugation method detected elevated total alkalinity and Ca concentrations in soil pore waters from feedstock-amended soils, whereas the effect of feedstock amendment was not detectable in pore waters extracted with lysimeters. The high tensions applied during centrifugation likely capture weathering products dissolved in meso- and micropore water, which lysimeters cannot extract. These findings suggest that centrifugation provides a scalable, low-cost approach for ERW monitoring, with implications for improving existing MRV protocols.
{"title":"Utilizing Soil Centrifugation for Accurate Estimates of Carbon Dioxide Removal via Enhanced Rock Weathering.","authors":"Gregory Jones,Ziyan Zhang,Katherine Clayton,Lena Lancastle,Athanasios Paschalis,Bonnie Waring","doi":"10.1021/acs.est.5c03699","DOIUrl":"https://doi.org/10.1021/acs.est.5c03699","url":null,"abstract":"Enhanced rock weathering (ERW) is a promising CO2 removal (CDR) strategy that aims to accelerate the natural process of silicate weathering to increase soil pore water alkalinity and sequester CO2. However, the measurement, reporting, and verification (MRV) of ERW remains challenging due to existing limitations of aqueous-phase sampling methodologies, such as passive and tension lysimeters, which may not fully capture weathering fluxes across varying soil moisture conditions. This study assesses the potential of a centrifugation-based pore water extraction method to improve the accuracy and reliability of ERW measurements. Using a forest ERW trial in Wales, UK, we compared the chemistry of soil pore waters obtained via lysimeters and centrifugation from feedstock-amended and control plots. The centrifugation method detected elevated total alkalinity and Ca concentrations in soil pore waters from feedstock-amended soils, whereas the effect of feedstock amendment was not detectable in pore waters extracted with lysimeters. The high tensions applied during centrifugation likely capture weathering products dissolved in meso- and micropore water, which lysimeters cannot extract. These findings suggest that centrifugation provides a scalable, low-cost approach for ERW monitoring, with implications for improving existing MRV protocols.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"20 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145752493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fire activity, including wildfires and urban fires, is increasing in frequency and severity, significantly impacting soil-borne metals such as chromium (Cr), which can be transformed from benign Cr(III) to toxic Cr(VI) during heating. However, the reaction pathway of Cr(VI) formation during wildfires remains unclear. We investigated the impacts of Fe-bearing minerals on the fire-induced formation of Cr(VI). Magnetite (Fe3O4) synthesized and doped with Cr(III), and Fe and Cr rich soils were heated up to 800 °C to investigate temperature-dependent transformations. For the synthetic system, Cr(III) oxyhydroxide (CrOOH) was oxidized to metastable Cr(VI) trioxide (CrO3) up to 600 °C, which spontaneously converted to Cr(III) oxide (Cr2O3) with increasing temperature to 800 °C. In the soil samples, Fe-bearing minerals reacted with Cr(III) hydroxide [Cr(OH)3] and chromite [FeCr2O4; Cr(III)] to form Cr(VI) and magnetite up to 600 °C, which react with each other with increasing temperature and reduce Cr(VI) to form chromite and hematite (α-Fe2O3). These findings highlight the role of Fe-bearing minerals in controlling the Cr(VI) formation and reduction pathway during fires. Our results have implications for understanding how wildfires contribute to the formation of toxic metals in soils, providing valuable insights for predicting the risks posed by wildfires.
{"title":"Nonlinear Redox Transformations of Chromium in Soil during Wildfire Heating: The Critical Role of Iron Mineralogy.","authors":"Alireza Namayandeh,Charles Lamb,Jose Luiz Sarabia,Mohsen Shakouri,Ethan Lopes,Juan Lezama Pacheco,Alexander Honeyman,AyoOluwateso Coker,Brandy Stewart,Sonia Tikoo,Derek Peak,Scott Fendorf","doi":"10.1021/acs.est.5c10407","DOIUrl":"https://doi.org/10.1021/acs.est.5c10407","url":null,"abstract":"Fire activity, including wildfires and urban fires, is increasing in frequency and severity, significantly impacting soil-borne metals such as chromium (Cr), which can be transformed from benign Cr(III) to toxic Cr(VI) during heating. However, the reaction pathway of Cr(VI) formation during wildfires remains unclear. We investigated the impacts of Fe-bearing minerals on the fire-induced formation of Cr(VI). Magnetite (Fe3O4) synthesized and doped with Cr(III), and Fe and Cr rich soils were heated up to 800 °C to investigate temperature-dependent transformations. For the synthetic system, Cr(III) oxyhydroxide (CrOOH) was oxidized to metastable Cr(VI) trioxide (CrO3) up to 600 °C, which spontaneously converted to Cr(III) oxide (Cr2O3) with increasing temperature to 800 °C. In the soil samples, Fe-bearing minerals reacted with Cr(III) hydroxide [Cr(OH)3] and chromite [FeCr2O4; Cr(III)] to form Cr(VI) and magnetite up to 600 °C, which react with each other with increasing temperature and reduce Cr(VI) to form chromite and hematite (α-Fe2O3). These findings highlight the role of Fe-bearing minerals in controlling the Cr(VI) formation and reduction pathway during fires. Our results have implications for understanding how wildfires contribute to the formation of toxic metals in soils, providing valuable insights for predicting the risks posed by wildfires.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"9 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145752496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Exposure to chemicals is a significant risk factor affecting human health, yet uncovering the risks posed by complex indoor chemical mixtures remains an immense challenge. In this study, we systematically screened 969 semivolatile organic compounds (SVOCs) in 395 indoor dust and silicone passive air samples from 31 Chinese provinces. A total of 216 SVOCs were detected across 201 bedrooms, with 95 compounds codetected in both dust and air samples. We found that SVOC concentrations in indoor air were significantly correlated with indoor temperature (r = 0.19) and relative humidity (r = -0.34) and were also significantly influenced by region, season, ventilation time, and interior finishes. Daily intakes of ΣSVOCs from indoor air were 3.15 to 13.6 times those from indoor dust for infants, toddlers, children, teenagers, and adults. The cumulative noncarcinogenic and carcinogenic risks of indoor SVOC mixtures were non-negligible across five age groups, with 15.9-38.8% and 9.5-50.7% of sites exceeding acceptable levels, respectively. Notably, the risk posed by inhaling gaseous SVOCs accounted for 49.6% to 82.8% of the total risk, surpassing the risk from ingestion and dermal uptake of dust. Overall, this study contributes valuable insights into indoor chemical mixtures and their health risks, informing targeted interventions.
{"title":"Unveiling the Characteristics of Indoor Chemical Mixtures and Their Health Risks across China.","authors":"Chen Yang,Xuemei Wang,Xianbao Dong,Tianxiang Wu,Bole Ma,Jingyan Zhao,Qing Xie,Jingwen Chen,Kiwao Kadokami,Xuehua Li","doi":"10.1021/acs.est.5c06124","DOIUrl":"https://doi.org/10.1021/acs.est.5c06124","url":null,"abstract":"Exposure to chemicals is a significant risk factor affecting human health, yet uncovering the risks posed by complex indoor chemical mixtures remains an immense challenge. In this study, we systematically screened 969 semivolatile organic compounds (SVOCs) in 395 indoor dust and silicone passive air samples from 31 Chinese provinces. A total of 216 SVOCs were detected across 201 bedrooms, with 95 compounds codetected in both dust and air samples. We found that SVOC concentrations in indoor air were significantly correlated with indoor temperature (r = 0.19) and relative humidity (r = -0.34) and were also significantly influenced by region, season, ventilation time, and interior finishes. Daily intakes of ΣSVOCs from indoor air were 3.15 to 13.6 times those from indoor dust for infants, toddlers, children, teenagers, and adults. The cumulative noncarcinogenic and carcinogenic risks of indoor SVOC mixtures were non-negligible across five age groups, with 15.9-38.8% and 9.5-50.7% of sites exceeding acceptable levels, respectively. Notably, the risk posed by inhaling gaseous SVOCs accounted for 49.6% to 82.8% of the total risk, surpassing the risk from ingestion and dermal uptake of dust. Overall, this study contributes valuable insights into indoor chemical mixtures and their health risks, informing targeted interventions.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"230 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145752530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mallory S Ho,Gianni F Vettese,Katherine Morris,Jonathan R Lloyd,Christopher Boothman,Samuel Shaw,Kathy Dardenne,Carolyn Pearce,Gareth T W Law
99Tc is a long-lived radioactive fission product whose subsurface mobility is governed by redox conditions. Under oxic conditions, soluble Tc(VII)O4- is mobile, whereas under reducing conditions, poorly soluble Tc(IV) phases limit transport. Microcosm studies have frequently reported TcO2-like solids and, less consistently, Tc(IV)-sulfides. The stability of Tc(IV)-sulfides under environmentally relevant conditions remains unclear. Here, we used flowing sediment columns representative of the Sellafield subsurface to examine Tc speciation and stability over ∼1 year. Under reducing conditions, >90% of added TcO4- (400 μg) was retained under both Fe(III)- and sulfate-reducing conditions. X-ray absorption spectroscopy showed TcO2-like phases dominated in Fe(III)-reducing columns, while Tc(IV)-sulfides dominated after sustained sulfate reduction. Sequential extractions indicated that Tc in sulfidic sediments was more recalcitrant (≤23% released by weak acids) than in Fe(III)-reducing systems (∼60% released). With oxic groundwater pumping, effluent Tc sourced from the sediments rose rapidly. Over 160 days, the sulfidic columns remobilized ∼25% of their Tc inventory compared to ∼50% in Fe(III)-reducing columns. The Tc(IV)-sulfides also gradually oxidized to form TcO2 phases. While Tc(IV)-sulfides may enhance Tc retention under reducing conditions, TcO2 phases more likely govern 99Tc mobility during long-term redox cycling. Our findings provide new constraints for modeling Tc fate at contaminated sites and in radioactive waste disposal.
{"title":"Technetium Retention and Remobilization Potential after Prolonged Reaction in Fe(III)- and Sulfate-Reducing Model Aquifer Systems.","authors":"Mallory S Ho,Gianni F Vettese,Katherine Morris,Jonathan R Lloyd,Christopher Boothman,Samuel Shaw,Kathy Dardenne,Carolyn Pearce,Gareth T W Law","doi":"10.1021/acs.est.5c12024","DOIUrl":"https://doi.org/10.1021/acs.est.5c12024","url":null,"abstract":"99Tc is a long-lived radioactive fission product whose subsurface mobility is governed by redox conditions. Under oxic conditions, soluble Tc(VII)O4- is mobile, whereas under reducing conditions, poorly soluble Tc(IV) phases limit transport. Microcosm studies have frequently reported TcO2-like solids and, less consistently, Tc(IV)-sulfides. The stability of Tc(IV)-sulfides under environmentally relevant conditions remains unclear. Here, we used flowing sediment columns representative of the Sellafield subsurface to examine Tc speciation and stability over ∼1 year. Under reducing conditions, >90% of added TcO4- (400 μg) was retained under both Fe(III)- and sulfate-reducing conditions. X-ray absorption spectroscopy showed TcO2-like phases dominated in Fe(III)-reducing columns, while Tc(IV)-sulfides dominated after sustained sulfate reduction. Sequential extractions indicated that Tc in sulfidic sediments was more recalcitrant (≤23% released by weak acids) than in Fe(III)-reducing systems (∼60% released). With oxic groundwater pumping, effluent Tc sourced from the sediments rose rapidly. Over 160 days, the sulfidic columns remobilized ∼25% of their Tc inventory compared to ∼50% in Fe(III)-reducing columns. The Tc(IV)-sulfides also gradually oxidized to form TcO2 phases. While Tc(IV)-sulfides may enhance Tc retention under reducing conditions, TcO2 phases more likely govern 99Tc mobility during long-term redox cycling. Our findings provide new constraints for modeling Tc fate at contaminated sites and in radioactive waste disposal.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"4 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145752532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The interaction of copper nanoparticles (CuNPs) from anthropogenic and natural sources in the environment with dissolved organic matter (DOM) governs their occurrence, fate, and transportation. Here, we report that DOM can mediate CuNP transformation into atomically dispersed zerovalent copper single atoms (Cu0-SAs) at water/mineral interfaces. The mechanism proposes that the ortho-phenolic hydroxyl of DOM likely forms the five-membered ring structure with copper atoms on the CuNP surface, inducing inner-sphere electron transfer to weaken Cu–Cu bonds and enabling the liberation of Cu0-SAs and stabilization via Cu–O bonds on natural mineral surfaces, which diverges fundamentally from the conventional dissolution process. Cu0-SAs represent a paradoxical species that exhibit both relatively high environmental toxicity and stability, combining enhanced bactericidal activity, decreased copper ion leaching compared with parent CuNPs, and resistance to aggregation under reducing conditions. This study unveils an unreported CuNP transformation process in the environment, demonstrating Cu0-SAs as an emerging yet significant copper species. Our findings should be helpful for better understanding the fate, migration, and toxicity of copper in the ecosystem by identifying atomic-level copper intermediates.
{"title":"Copper Nanoparticles Atomized into Zerovalent Copper Single Atoms at Water/Mineral Interfaces Mediated by ortho-Phenolic Hydroxyl of Dissolved Organic Matter","authors":"Haibin Li, Yina Guan, Chunguang Liu, Site Han, Yating Zhang, Lingshuai Kong, Jinhua Zhan","doi":"10.1021/acs.est.5c15342","DOIUrl":"https://doi.org/10.1021/acs.est.5c15342","url":null,"abstract":"The interaction of copper nanoparticles (CuNPs) from anthropogenic and natural sources in the environment with dissolved organic matter (DOM) governs their occurrence, fate, and transportation. Here, we report that DOM can mediate CuNP transformation into atomically dispersed zerovalent copper single atoms (Cu<sup>0</sup>-SAs) at water/mineral interfaces. The mechanism proposes that the <i>ortho</i>-phenolic hydroxyl of DOM likely forms the five-membered ring structure with copper atoms on the CuNP surface, inducing inner-sphere electron transfer to weaken Cu–Cu bonds and enabling the liberation of Cu<sup>0</sup>-SAs and stabilization via Cu–O bonds on natural mineral surfaces, which diverges fundamentally from the conventional dissolution process. Cu<sup>0</sup>-SAs represent a paradoxical species that exhibit both relatively high environmental toxicity and stability, combining enhanced bactericidal activity, decreased copper ion leaching compared with parent CuNPs, and resistance to aggregation under reducing conditions. This study unveils an unreported CuNP transformation process in the environment, demonstrating Cu<sup>0</sup>-SAs as an emerging yet significant copper species. Our findings should be helpful for better understanding the fate, migration, and toxicity of copper in the ecosystem by identifying atomic-level copper intermediates.","PeriodicalId":36,"journal":{"name":"环境科学与技术","volume":"75 1","pages":""},"PeriodicalIF":9.028,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145732208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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