Nano zero-valent iron modified biochar (nZVI-BC) is widely regarded as an efficient and environmentally friendly material for stabilising heavy metals in soil. However, the intrinsic relationship among soil microbial community structure, heavy metal speciation, and soil organic carbon (SOC) sequestration remains unclear. This study comprehensively evaluated the influence of nZVI-BC on the stabilisation of heavy metals and variation of SOC fractions, and the associated microbial community structure, along with conducting correlation analyses. Results indicated that following nZVI-BC treatment, the available forms of Cd, Pb, and Zn in soil decreased by 42.7%, 48.0%, and 39.1%, respectively, with greater conversion to Fe-Mn oxide-bound, organically bound, and residual forms. In comparison to pristine biochar, nZVI-BC amendment resulted in a greater increase in mineral-associated organic carbon (MAOC), a reduction in particulate organic carbon (POC) content, a lower POC/MAOC ratio, and decreased soil respiration. Furthermore, nZVI-BC treatment significantly increased the relative abundance of the bacterial genera (Brevundimonas and Noviherbaspirillum) associated with SOC stabilisation. The SOC and MAOC content exhibited a positive correlation with these bacterial abundances. The correlation coefficient between SOC and residual Pb was 0.043, while that between MAOC and Fe-Mn-bound Zn was 0.104. The findings suggests that the combined effect of active carbon sequestration by Brevundimonas and Noviherbaspirillum, along with passive carbon sequestration of residual Pb and Fe-Mn-bound Zn from iron oxides introduced by nZVI-BC, has a positive effect on SOC sequestration. This study provides a novel perspective on the comprehensive evaluation of the environmental benefits of nZVI-BC in soil heavy metal remediation.
{"title":"nZVI-BC strengthens organic carbon sequestration driven by the modulation of soil microbial community and heavy metal speciation","authors":"Chunyun Jia, Xiaoxuan Ding, Xiuyun Han, Changfeng Liu, Xiaojun Li, Xiangfeng Zeng, Chenyang Xue","doi":"10.1016/j.jhazmat.2026.141371","DOIUrl":"https://doi.org/10.1016/j.jhazmat.2026.141371","url":null,"abstract":"Nano zero-valent iron modified biochar (nZVI-BC) is widely regarded as an efficient and environmentally friendly material for stabilising heavy metals in soil. However, the intrinsic relationship among soil microbial community structure, heavy metal speciation, and soil organic carbon (SOC) sequestration remains unclear. This study comprehensively evaluated the influence of nZVI-BC on the stabilisation of heavy metals and variation of SOC fractions, and the associated microbial community structure, along with conducting correlation analyses. Results indicated that following nZVI-BC treatment, the available forms of Cd, Pb, and Zn in soil decreased by 42.7%, 48.0%, and 39.1%, respectively, with greater conversion to Fe-Mn oxide-bound, organically bound, and residual forms. In comparison to pristine biochar, nZVI-BC amendment resulted in a greater increase in mineral-associated organic carbon (MAOC), a reduction in particulate organic carbon (POC) content, a lower POC/MAOC ratio, and decreased soil respiration. Furthermore, nZVI-BC treatment significantly increased the relative abundance of the bacterial genera (<em>Brevundimonas</em> and <em>Noviherbaspirillum</em>) associated with SOC stabilisation. The SOC and MAOC content exhibited a positive correlation with these bacterial abundances. The correlation coefficient between SOC and residual Pb was 0.043, while that between MAOC and Fe-Mn-bound Zn was 0.104. The findings suggests that the combined effect of active carbon sequestration by <em>Brevundimonas</em> and <em>Noviherbaspirillum</em>, along with passive carbon sequestration of residual Pb and Fe-Mn-bound Zn from iron oxides introduced by nZVI-BC, has a positive effect on SOC sequestration. This study provides a novel perspective on the comprehensive evaluation of the environmental benefits of nZVI-BC in soil heavy metal remediation.","PeriodicalId":361,"journal":{"name":"Journal of Hazardous Materials","volume":"16 1","pages":""},"PeriodicalIF":13.6,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101905","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}
Pub Date : 2026-02-03DOI: 10.1016/j.jhazmat.2026.141373
Shaoyang Tao, Jun Gao, Bin He, Tong Zhang, Baowei Chen, Yongguang Yin, Jianbo Shi, Yuxiang Mao, Ligang Hu, Guibin Jiang
Microbial mercury methylation is the key step responsible for the high toxicity and bioaccumulation potential of mercury. Since metabolic pathways serve as a bridge between mercury methylation and microbial activity, studying mercury methylation from the perspective of metabolic pathways will offer valuable insights into its underlying mechanism and integration into microbial metabolism. This review aims to summarize current understanding of the metabolic pathways that supply methyl groups for mercury methylation and to elucidate the relationships between them. The acetyl-coenzyme A pathway is extensively studied and well recognized for its role in methyl group transfer. The Wolfe cycle, representing the methanogenesis pathway in methanogenic archaea, has recently been identified as a distinct source of methyl groups contributing to mercury methylation. In addition, at the chemical level, S-adenosyl-L-methionine from the methionine biosynthesis pathway has been shown to donate a methyl group to mercury via the HgcAB complex, although this process has not yet been validated in vivo. Finally, the dimethylsulfoniopropionate degradation pathway is proposed as a speculative and potential route for mercury methylation. By integrating these pathways, we provide a comprehensive overview of their interconnections, demonstrating that microbial mercury methylation is embedded within the broader framework of one-carbon metabolism. The close association between methylation and one-carbon flux suggests that mercury methylation may function as an interspecies competition strategy that enhances microbial survival in mercury-rich environments. This pathway-centered perspective advances our understanding of the biochemical basis of microbial mercury methylation and may inform future research into its environmental controls and microbial ecology.
{"title":"Understanding Microbial Mercury Methylation via Metabolic Pathways: Processes Associated with One-Carbon Metabolism","authors":"Shaoyang Tao, Jun Gao, Bin He, Tong Zhang, Baowei Chen, Yongguang Yin, Jianbo Shi, Yuxiang Mao, Ligang Hu, Guibin Jiang","doi":"10.1016/j.jhazmat.2026.141373","DOIUrl":"https://doi.org/10.1016/j.jhazmat.2026.141373","url":null,"abstract":"Microbial mercury methylation is the key step responsible for the high toxicity and bioaccumulation potential of mercury. Since metabolic pathways serve as a bridge between mercury methylation and microbial activity, studying mercury methylation from the perspective of metabolic pathways will offer valuable insights into its underlying mechanism and integration into microbial metabolism. This review aims to summarize current understanding of the metabolic pathways that supply methyl groups for mercury methylation and to elucidate the relationships between them. The acetyl-coenzyme A pathway is extensively studied and well recognized for its role in methyl group transfer. The Wolfe cycle, representing the methanogenesis pathway in methanogenic archaea, has recently been identified as a distinct source of methyl groups contributing to mercury methylation. In addition, at the chemical level, S-adenosyl-L-methionine from the methionine biosynthesis pathway has been shown to donate a methyl group to mercury via the HgcAB complex, although this process has not yet been validated in vivo. Finally, the dimethylsulfoniopropionate degradation pathway is proposed as a speculative and potential route for mercury methylation. By integrating these pathways, we provide a comprehensive overview of their interconnections, demonstrating that microbial mercury methylation is embedded within the broader framework of one-carbon metabolism. The close association between methylation and one-carbon flux suggests that mercury methylation may function as an interspecies competition strategy that enhances microbial survival in mercury-rich environments. This pathway-centered perspective advances our understanding of the biochemical basis of microbial mercury methylation and may inform future research into its environmental controls and microbial ecology.","PeriodicalId":361,"journal":{"name":"Journal of Hazardous Materials","volume":"1 1","pages":""},"PeriodicalIF":13.6,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101906","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}
{"title":"Multi-dimensional assessment of metal welding fumes exposure and oxidative stress-driven health risks: Insights from external monitoring, respiratory replica monitoring, and DTT activity","authors":"Yalin Liu, Yifan Qu, Yi Wanga, Ruixin Yang, Yihua Chai, Yanqiu Huang","doi":"10.1016/j.jhazmat.2026.141348","DOIUrl":"https://doi.org/10.1016/j.jhazmat.2026.141348","url":null,"abstract":"","PeriodicalId":361,"journal":{"name":"Journal of Hazardous Materials","volume":"1 1","pages":""},"PeriodicalIF":13.6,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110963","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}
Pub Date : 2026-02-02DOI: 10.1016/j.jhazmat.2026.141337
Yuting Liu, Dou Li, Yan Wang, Yuqing Zhang, Yahui Qiu, Fengzhu Zhou, Yuejiao Li, Ruhai Liu
This study investigates the photochemical reduction of mercury in urban total suspended particulates (TSP) and its key drivers, aiming to elucidate particulate-bound mercury (PHg) transformation under multiple environmental factors. Using year-round Qingdao field samples, the effects of light intensity, UV wavelength, ozone, particle moisture content, and ionic composition were examined through controlled experiments and multivariate analyses. The photoreduction rate of mercury in TSP exhibited pronounced seasonal variability, following the order summer > spring > autumn > winter, closely linked to solar radiation and particle composition. As light intensity increased from 480 W/m2 to 1100 W/m2, elemental mercury (Hg0) release increased by approximately fourfold. UV radiation generally promoted PHg photoreduction, whereas under UVB irradiation, Hg0 oxidation exceeded Hg2+ reduction due to the strong oxidative capacity of UVB. Increasing ozone concentrations from 0 to 100 ppb reduced Hg0 release by up to 30.7%, while increasing particle moisture content from 0% to 100% enhanced the photoreduction ratio from 2.28 ± 0.62% to 12.51 ± 2.16%. Seasonal variations in water-soluble ions exerted complex influences on mercury reduction: low-solubility HgSO4 facilitated PHg photolysis; elevated NO3- promoted Hg0 oxidation through ·OH radical formation, suppressing net release; and Cl- inhibited reduction via forming HgCl42-. Overall, light intensity, UV wavelength, ozone, moisture content, and ionic composition are dominant factors of PHg photoreduction. This study highlights the critical role of photochemically formed secondary aerosols, particularly sulfates, in enhancing mercury reduction in particles, providing new insights into aerosol-driven mercury cycling and supporting improved regional pollution control and global mercury modeling.
{"title":"Photochemical release characteristics of particle-bound mercury in the atmosphere and its influencing factors","authors":"Yuting Liu, Dou Li, Yan Wang, Yuqing Zhang, Yahui Qiu, Fengzhu Zhou, Yuejiao Li, Ruhai Liu","doi":"10.1016/j.jhazmat.2026.141337","DOIUrl":"https://doi.org/10.1016/j.jhazmat.2026.141337","url":null,"abstract":"This study investigates the photochemical reduction of mercury in urban total suspended particulates (TSP) and its key drivers, aiming to elucidate particulate-bound mercury (PHg) transformation under multiple environmental factors. Using year-round Qingdao field samples, the effects of light intensity, UV wavelength, ozone, particle moisture content, and ionic composition were examined through controlled experiments and multivariate analyses. The photoreduction rate of mercury in TSP exhibited pronounced seasonal variability, following the order summer > spring > autumn > winter, closely linked to solar radiation and particle composition. As light intensity increased from 480<!-- --> <!-- -->W/m<sup>2</sup> to 1100<!-- --> <!-- -->W/m<sup>2</sup>, elemental mercury (Hg<sup>0</sup>) release increased by approximately fourfold. UV radiation generally promoted PHg photoreduction, whereas under UVB irradiation, Hg<sup>0</sup> oxidation exceeded Hg<sup>2+</sup> reduction due to the strong oxidative capacity of UVB. Increasing ozone concentrations from 0 to 100 ppb reduced Hg<sup>0</sup> release by up to 30.7%, while increasing particle moisture content from 0% to 100% enhanced the photoreduction ratio from 2.28 ± 0.62% to 12.51 ± 2.16%. Seasonal variations in water-soluble ions exerted complex influences on mercury reduction: low-solubility HgSO<sub>4</sub> facilitated PHg photolysis; elevated NO<sub>3</sub><sup>-</sup> promoted Hg<sup>0</sup> oxidation through <sup>·</sup>OH radical formation, suppressing net release; and Cl<sup>-</sup> inhibited reduction via forming HgCl<sub>4</sub><sup>2-</sup>. Overall, light intensity, UV wavelength, ozone, moisture content, and ionic composition are dominant factors of PHg photoreduction. This study highlights the critical role of photochemically formed secondary aerosols, particularly sulfates, in enhancing mercury reduction in particles, providing new insights into aerosol-driven mercury cycling and supporting improved regional pollution control and global mercury modeling.","PeriodicalId":361,"journal":{"name":"Journal of Hazardous Materials","volume":"19 6 1","pages":""},"PeriodicalIF":13.6,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098427","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}
Pub Date : 2026-02-02DOI: 10.1016/j.jhazmat.2026.141359
Zhen Chen, Xiaodong Ge, Lei Duan
{"title":"Mapping critical loads of cadmium in Chinese soils based on multiple environmental effects","authors":"Zhen Chen, Xiaodong Ge, Lei Duan","doi":"10.1016/j.jhazmat.2026.141359","DOIUrl":"https://doi.org/10.1016/j.jhazmat.2026.141359","url":null,"abstract":"","PeriodicalId":361,"journal":{"name":"Journal of Hazardous Materials","volume":"8 1","pages":""},"PeriodicalIF":13.6,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146110300","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}
In karst regions, soil cadmium (Cd) enrichment is commonly attributed to underlying carbonate bedrock weathering. However, the quantitative contribution of anthropogenic Cd in areas remote from urban and industrial centers is poorly understood, limiting effective pollution management. This study aimed to identify and quantify the sources of Cd in a typical karst region. We investigated Cd pollution and sources in the topsoil of mountainous and farmland areas by integrating high field strength elements (HFSEs), rare earth elements (REEs), the positive matrix factorization (PMF) model, and Cd stable isotope analysis. The median Cd concentration in the studied topsoil was 7.88 mg/kg (average 8.07 mg/kg), which is 13.13 times greater than China’s soil risk control standard (0.60 mg/kg, pH 6.50--7.50), with Cd isotopic compositions (δ114/110Cd) ranging from -0.233‰ to 0.159‰. The HFSEs, REEs and PMF results indicated substantial anthropogenic influence. The Cd isotope results revealed that the Cd in mountain soils mainly originated from bedrock weathering (55.0%), with contributions from metal smelting (19.8%), traffic (18.8%), and coal combustion (6.4%). In agricultural soils, anthropogenic sources dominated (72.9%), primarily comprising emissions from metal smelting and traffic (each 21.3%) and coal combustion (14.0%), followed by fertilizer application (16.3%), with bedrock contributing 27.1%. These findings demonstrate that atmospheric particulate transport efficiently delivers Cd to soils far from pollution centers, highlighting the critical need to include long-range atmospheric transport in the risk assessment and management of Cd pollution in karst regions. The integrated geochemical and isotope approach provides a robust, transferable framework for source apportionment and for developing effective heavy metal pollution control strategies in similar environments worldwide.
{"title":"Analysis of Cadmium Sources in Surface Soil in Typical Karst Regions: Anthropogenic Input Contribution and Atmospheric Transport Impact","authors":"Zhe Liu, Guangyi Sun, Xian Wu, Weihai Yu, Heng Yao, Yu Lin, Chunlin Fu, Jinling Liu, Xinbin Feng","doi":"10.1016/j.jhazmat.2026.141349","DOIUrl":"https://doi.org/10.1016/j.jhazmat.2026.141349","url":null,"abstract":"In karst regions, soil cadmium (Cd) enrichment is commonly attributed to underlying carbonate bedrock weathering. However, the quantitative contribution of anthropogenic Cd in areas remote from urban and industrial centers is poorly understood, limiting effective pollution management. This study aimed to identify and quantify the sources of Cd in a typical karst region. We investigated Cd pollution and sources in the topsoil of mountainous and farmland areas by integrating high field strength elements (HFSEs), rare earth elements (REEs), the positive matrix factorization (PMF) model, and Cd stable isotope analysis. The median Cd concentration in the studied topsoil was 7.88<!-- --> <!-- -->mg/kg (average 8.07<!-- --> <!-- -->mg/kg), which is 13.13 times greater than China’s soil risk control standard (0.60<!-- --> <!-- -->mg/kg, pH 6.50--7.50), with Cd isotopic compositions (δ<sup>114/110</sup>Cd) ranging from -0.233‰ to 0.159‰. The HFSEs, REEs and PMF results indicated substantial anthropogenic influence. The Cd isotope results revealed that the Cd in mountain soils mainly originated from bedrock weathering (55.0%), with contributions from metal smelting (19.8%), traffic (18.8%), and coal combustion (6.4%). In agricultural soils, anthropogenic sources dominated (72.9%), primarily comprising emissions from metal smelting and traffic (each 21.3%) and coal combustion (14.0%), followed by fertilizer application (16.3%), with bedrock contributing 27.1%. These findings demonstrate that atmospheric particulate transport efficiently delivers Cd to soils far from pollution centers, highlighting the critical need to include long-range atmospheric transport in the risk assessment and management of Cd pollution in karst regions. The integrated geochemical and isotope approach provides a robust, transferable framework for source apportionment and for developing effective heavy metal pollution control strategies in similar environments worldwide.","PeriodicalId":361,"journal":{"name":"Journal of Hazardous Materials","volume":"67 1","pages":""},"PeriodicalIF":13.6,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098428","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}
Metallurgical production is a global pillar industry, and poses significant health risks to surrounding residents. Rapid identification of risks is crucial for mitigating the severe impact of metallurgical activities on nearby residents. In this study, a modified CALPUFF model (M-CALPUFF) and a wind-corrected soil heavy metal(loid)s (HMs) prediction model based on Gaussian plume diffusion model (GWS model) were constructed to assess the environmental risks of HMs emissions from metallurgical enterprises. These models can identify high-risk areas using concise computational approach with limited raw data. The M-CALPUFF and the GWS model were used to quantify the concentration and spatial distribution of HMs in dustfall and soil respectively, and the results were consistent with empirical measurement. Validation against 156 dust samples demonstrated that M-CALPUFF achieved ≥70% accuracy at > 60% of sampling points. The GWS model simulation of 21 test sets showed over 95.2% accuracy within a 95% prediction interval for all tests. Finally, the HMs risk of the entire smelting area was evaluated. Spatial risk delineation revealed distinct patterns: children exhibited broader non-carcinogenic risk areas driven by frequent hand-to-mouth soil ingestion, whereas adults faced more extensive carcinogenic risks due to cumulative chronic exposure. This work provides a new method for predicting the HMs concentration in smelting areas and a new framework for identifying high-risk areas.
{"title":"Division Approach of high-risk heavy metal(loid)s areas in metallurgical industrial regions: A practical inversion approach","authors":"Mingyue Li, Chen Zhang, Linling Wang, Jinyang Zhou, Rongbing Fu, Weimin Guo, Zhemin Shen","doi":"10.1016/j.jhazmat.2026.141350","DOIUrl":"https://doi.org/10.1016/j.jhazmat.2026.141350","url":null,"abstract":"Metallurgical production is a global pillar industry, and poses significant health risks to surrounding residents. Rapid identification of risks is crucial for mitigating the severe impact of metallurgical activities on nearby residents. In this study, a modified CALPUFF model (M-CALPUFF) and a wind-corrected soil heavy metal(loid)s (HMs) prediction model based on Gaussian plume diffusion model (GWS model) were constructed to assess the environmental risks of HMs emissions from metallurgical enterprises. These models can identify high-risk areas using concise computational approach with limited raw data. The M-CALPUFF and the GWS model were used to quantify the concentration and spatial distribution of HMs in dustfall and soil respectively, and the results were consistent with empirical measurement. Validation against 156 dust samples demonstrated that M-CALPUFF achieved ≥70% accuracy at > 60% of sampling points. The GWS model simulation of 21 test sets showed over 95.2% accuracy within a 95% prediction interval for all tests. Finally, the HMs risk of the entire smelting area was evaluated. Spatial risk delineation revealed distinct patterns: children exhibited broader non-carcinogenic risk areas driven by frequent hand-to-mouth soil ingestion, whereas adults faced more extensive carcinogenic risks due to cumulative chronic exposure. This work provides a new method for predicting the HMs concentration in smelting areas and a new framework for identifying high-risk areas.","PeriodicalId":361,"journal":{"name":"Journal of Hazardous Materials","volume":"37 1","pages":""},"PeriodicalIF":13.6,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146098429","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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