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Journal of Environmental Sciences 2024年第4期138卷 266-276页

作者： Xu Liu Xun wang dingyong wang College of Resources and Environment Southwest UniversityChongqing 400715China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

The tree ring has been regarded as an emerging archive to reconstruct historical atmospheric mercury(Hg)trends,but with the large knowledge gaps in the reliability.In this study,we comprehensively evaluated the Hg source,radial translocation and age effect of Masson pine(Pinus massoniana)tree ring at Mt.Jinyun in Chongqing,to assess the suitability of such tree ring as the archive of atmospheric Hg.Results showed that distinct variabilities among Masson pine tree-ring Hg concentration profiles.The Hg concentration significantly increased along with stem height(P<0.05),indicating the Hg in tree rings mainly derived from foliage uptake atmospheric Hg.We found a distinct age effect that the tree ring of young trees had the higher Hg concentration.Besides,we used the advection-diffusion model to demonstrate how Hg concentration shifted by the advection or/and diffusion in tree rings.The modeling results showed that the advection induced radial translocation during the young growth period of tree was a plausible mechanism to result in the tree-ring Hg record largely different from the trend of anthropogenic Hg emissions in Chongqing.We finally suggest that in further Hg dendrochemistry,better discarding the tree-ring Hg profile of the young growth period to reduce impacts of the radial translocation and age effect.

关键词： Masson pine Tree-ring mercury Radial translocation Tree age effect

Mercury accumulation and dynamics in montane forests along an elevation gradient in Southwest China

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Journal of Environmental Sciences 2022年第9期34卷 1-10页

作者： Shufang Zeng Xun wang Wei Yuan Ji Luo dingyong wang College of Resources and Environment Southwest UniversityChongqing 400715China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences&Ministry of Water ConservancyChengdu 610041China

Understanding atmospheric mercury(Hg) accumulation in remote montane forests is critical to assess the Hg ecological risk to wildlife and human health. To quantify impacts of vegetation, climatic and topographic factors on Hg accumulation in montane forests, we assessed the Hg distribution and stoichiometric relations among Hg, carbon(C), and nitrogen(N) in four forest types along the elevation of Mt. Gongga. Our results show that Hg concentration in plant tissues follows the descending order of litter > leaf, bark > root > branch > bole wood, indicating the importance of atmospheric Hg uptake by foliage for Hg accumulation in plants. The foliar Hg/C(from 237.0 ± 171.4 to 56.8 ± 27.7 μg/kg) and Hg/N(from 7.5 ± 3.9 to 2.5 ± 1.2 mg/kg) both decrease along the elevation. These elevation gradients are caused by the heterogeneity of vegetation uptake of atmospheric Hg and the variation of atmospheric Hg ° concentrations at different altitudes. Organic soil Hg accumulation is controlled by forest types, topographic and climatic factors, with the highest concentration in the mixed forest(244.9 ± 55.7 μg/kg) and the lowest value in the alpine forest(151.9 ±44.5 μg/kg). Further analysis suggests that soil Hg is positively correlated to C( r^(2) = 0.66) and N( r^(2) = 0.57), and Hg/C and Hg/N both increase with the soil depth. These stoichiometric relations highlight the combined effects from environmental and climatic factors which mediating legacy Hg accumulation and selective Hg absorption during processes of organic soil mineralization.

关键词： Mercury deposition Montane forest Mercury accumulation Climate impact

Uncovering the magnetic response of open-shell graphene nanostructures on metallic surfaces at different doping levels

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 142-148页

作者： Zengfu Ou Jun wang Jihai Zhang Yukang Ding Shenwei Chen Wenya Zhai Jingcheng Li dingyong Zhong Donghui Guo School of Physics Sun Yat-sen UniversityGuangzhou 510275China Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices School of PhysicsSun Yat-sen UniversityGuangzhou 510275China State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-sen UniversityGuangzhou 510275China College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China

Open-shell graphene nanostructures(GNs)are promising candidates for future spintronics and quantum technologies.Recent progress based on on-surface synthetic approach has successfully created such GNs on metallic surfaces.Meanwhile,the doping effect of metallic surfaces is inevitably present and can significantly tune their electronic and magnetic properties.Here,we investigate the zigzag end states of open-shell 7-armchair graphene nanoribbons(7-AGNRs)on Au(111),Au(100)and Ag(111)surfaces.Combined with the manipulation of a scanning tunneling microscope,we demonstrate that the end states can be tuned from empty states to singly occupied states and to doubly occupied states by substrate doping.Furthermore,the singly occupied states can be finely tuned,with the occupancy number of the states and related magnetic behaviors uncovered by experiments at different temperatures and magnetic fields.Our results provide a comprehensive study of the magnetic response of open-shell GNs on metallic surfaces at different doping levels.

关键词： open-shell graphene nanostructures magnetic response metallic substrate doping Kondo resonance scanning tunneling microscopy/spectroscopy

Distribution of mercury and methylmercury in river water and sediment of typical manganese mining area

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Journal of Environmental Sciences 2022年第9期34卷 11-22页

作者： Yongjiang Zhang Tao Sun Ming Ma Xun wang Qing Xie Cheng Zhang Yongmin wang dingyong wang College of Resources and Environment Southwest UniversityChongqing 400715China Department of Environment and Quality Test Chongqing Chemical Industry Vocational CollegeChongqing 401220China School of Agricultural Sciences Zhengzhou UniversityZhengzhou 450001China

Manganese(Mn) ores contain substantial concentrations of mercury(Hg), and mining and smelting of Mn ores can bring Hg into the surrounding aquatic environment through atmospheric deposition, leaching of electrolytic Mn residue and Mn gangue dump. However, limited is known that how these processes influence the environmental behaviors of Hg in waterbody. Therefore, the seasonal distribution and existing form of Hg in water and sediment in one Mn ore area in Xiushan County, Chongqing were investigated. Our results showed that the mean Hg and methylmercury(Me Hg) concentrations in water( n = 35) were 5.8 ± 4.6 ng/L and 0.22 ± 0.14 ng/L, respectively. The mean Hg concentrations in retained riverbed and fluvial bank sediment( n = 35) were 0.74 ± 0.26 mg/kg and 0.63 ± 0.27 mg/kg, respectively(the mean Me Hg concentrations were 0.64 ± 0.40 μg/kg and 0.51 ± 0.30 μg/kg, respectively). It indicated that the mining and smelting of Mn ores were the main sources of anthropogenic Hg, and Mn may inhibit Hg methylation in rivers in Mn ore areas. Mercury in the bound to iron/Mn(Fe/Mn) oxides of low crystallinity fraction(Hg-OX) accounted for 4.01% and 5.25% of the total Hg concentrations in the retained riverbed and fluvial bank sediment, respectively. The amount of Hg bound to Fe/Mn oxides in sediment increased significantly due to the manganese mining activities in the investigated area. Therefore, it could be hypothesized that high Hg concentrations in river sediment in Mn mining areas are closely related to high Mn concentration in sediment.

关键词： Mn mining area Hg MeHg Distribution characteristics Fractionation of Hg

Role of the rhizosphere of a flooding-tolerant herb in promoting mercury methylation in water-level fluctuation zones

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Journal of Environmental Sciences 2022年第9期34卷 139-151页

作者： Juan wang Yuping Xiang Xiaosong Tian Cheng Zhang Guiqing Gong Jinping Xue Tao Jiang dingyong wang Yongmin wang Interdisciplinary Research Center for Agriculture Green Development in Yangtze River Basin College of Resources and EnvironmentSouthwest UniversityChongqing 400715China Laboratory of Environmental Nanotechnology&Health Effect Chinese Academy of SciencesResearch Center for Eco-Environmental SciencesBeijing 100085China College of Resources and Safety Chongqing Vocational Institute of EngineeringChongqing 402260China Institut des Sciences Analytiques et des Physico-Chimie pour l’Environnement et les Materiaux(IPREM) UMR 5254CNRSUniversitede Pau et des Pays de l’AdourPau 64000France

The water-level fluctuation zone(WLFZ) has been considered as a hotspot for mercury(Hg) methylation. Flooding-tolerant herbs are gradually acclimated to this water-land ecotone, tending to form substantial root systems for improving erosion resistance. Accompanying rhizosphere microzone plays crucial but unclear roles in methylmercury(Me Hg) formation in the WLFZ. Thus, we conducted this study in the WLFZ of the Three Gorges Reservoir, to explore effects of the rhizosphere of a dominant flooding-tolerant herb(bermudagrass) on Me Hg production. The elevated Hg and Me Hg in rhizosphere soils suggest that the rhizosphere environment provides favorable conditions for Hg accumulation and methylation. The increased bioavailable Hg and microbial activity in the rhizosphere probably serve as important factors driving Me Hg formation in the presence of bermudagrass. Simultaneously, the rhizosphere environments changed the richness, diversity, and distribution of hgc A-containing microorganisms. Here, a typical ironreducing bacterium( Geobacteraceae) has been screened, however, the majority of hgc A genes detected in rhizosphere, near-, and non-rhizosphere soils of the WLFZ were unclassified. Collectively, these results provide new insights into the elevated Me Hg production as related to microbial processes in the rhizosphere of perennial herbs in the WLFZ, with general implications for Hg cycling in other ecosystems with water-level fluctuations.

关键词： Three Gorges Reservoir Water-level fluctuation zone Rhizosphere soil Methylmercury Mercury methylator

Biochar affects methylmercury production and bioaccumulation in paddy soils: Insights from soil-derived dissolved organic matter

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Journal of Environmental Sciences 2022年第9期34卷 68-77页

作者： Siqi Zhang Mingxing wang Jiang Liu Shanyi Tian Xueling Yang Guangquan Xiao Guomin Xu Tao Jiang dingyong wang Interdisciplinary Research Centre for Agriculture Green Development in Yangtze River Basin Department of Environmental Sciences and EngineeringCollege of Resources and EnvironmentSouthwest UniversityChongqing 400716China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550002China Soil Ecology Laboratory College of Resources and Environmental SciencesNanjing Agricultural UniversityNanjing 210095China National Engineering Research Center for Compounding and Modification of Polymer Materials Guiyang 550014China Guizhou Material Industrial Technology Institute Guiyang 550014China Institute of Environment and Health Jianghan UniversityWuhan 430056China

Biochar has been used increasingly as a soil additive to control mercury(Hg) pollution in paddy rice fields. As the most active component of soil organic matter, soil dissolved organic matter(DOM) plays a vital role in the environmental fate of contaminants. However, there are very few studies to determine the impact of biochar on the Hg cycle in rice paddies using insights from DOM. This study used original and modified biochar to investigate their effect on DOM dynamics and their potential impact on methylmercury(MeHg) production and bioaccumulation in rice plants. Porewater DOM was collected to analyze the variations in soil-derived DOM in paddy soils. The results showed that the addition of biochar, whether in original or modified form, significantly reduced the bioaccumulation of MeHg in rice plants, especially in hulls and grains( p < 0.05). However, MeHg production in soils was only inhibited by the modified biochar. Biochar addition induced a significant increase in DOM’s aromaticity and molecular weight( p < 0.05), which decreased Hg bioavailability. Furthermore, enhanced microbial activity was also observed in DOM( p < 0.05), further increasing MeHg production in the soil. Thus, the effect of biochar on the fate of Hg cycle involves competition between the two different roles of DOM. This study identified a specific mechanism by which biochar affects Hg behavior in rice paddy soil and contributes to understanding the more general influence of biochar in agriculture and contaminant remediation.

关键词： Dissolved organic matter Mercury Methylmercury Biochar Rice

A simulation study of mercury release fluxes from soils in wet–dry rotation environment

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Journal of Environmental Sciences 2014年第7期26卷 1445-1452页

作者： Peng Liang Cheng Zhang Yongkui Yang dingyong wang College of Resources and Environment Southwest University School of Environmental and Resource Sciences Zhejiang A&F University Chongqing Key Laboratory of Soil Multi-scale Interfacial Process

A simulative mesocosm study was conducted to evaluate the influence of wet-dry rotation on mercury（Hg） flux from soil/water to air and the distribution of Hg species in water as well as Hg chemical fractions in soil. Three types of soil were employed including two kinds of paddy soil, Typic Purpli-Udic Cambosols（TPUC） and Xanthi-Udic Ferralosols（XUF）, as well as the Alluvial Soil（AS） from Three Gorge reservoir area in Chongqing, China. The results showed that Hg fluxes in wetting periods were significantly higher than that in drying periods. It might be due to the formation of a layer of stable air over the water surface in which some redox reactions promote evasion processes over the water surface. This result indicated that more Hg would be evaporated from the Three Gorge reservoir and paddy soil field during the flooding season. Hg fluxes were positively correlated with air temperature and solar irradiation, while negatively correlated with air humidity and the electronic conductivity of water. Hg fluxes from AS and TPUC were significantly higher than that from XUF, which might be due to the higher organic matter（OM） contents in XUF than TPUC and AS. The reduction processes of oxidized Hg were restrained due to the strong binding of Hg to OM, resulting in the decrease in Hg flux from the soil.

关键词： Mercury Flux Dynamic flux chamber Wet-dry rotation

Water level fluctuations influence microbial communities and mercury methylation in soils in the Three Gorges Reservoir,China

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Journal of Environmental Sciences 2018年第6期30卷 206-217页

作者： Yuping Xiang Yongmin wang Cheng Zhang Hong Shen dingyong wang College of Resources and Environment Southwest University Chongqing 400715 China Chongqing Engineering Research Center for Agricultural Non-point Source Pollution Control in the Three Gorges Reservoir Area Chongqing 400715 China Chongqing Key Laboratory of agricultural Resources and Environment Chongqing 400715 China

Reservoirs tend to have enhanced methylmercury（MeHg） concentrations compared to natural lakes and rivers, and water level fluctuations can promote MeHg production. Until now, little research has been conducted on the effects of microorganisms in soils for the formation of MeHg during different drying and flooding alternating conditions in the Three Gorges Reservoir（TGR）. This study aimed to understand how water level fluctuations affect soil microbial composition and mercury concentrations, and if such microbial variations are related to Hg methylation. The results showed that MeHg concentrations and the ratios of MeHg to THg（MeHg%） in soils were higher in the seasonally drying and flooding alternating areas（DFAs, 175–155 m） than those in the non-inundated（NIAs, 〉 175 m） and inundated areas（IAs, 〈 145 m）. However, MeHg% in all samples was less than 1%, indicating that the Hg methylation activity in the soils of the TGR was under a low level. 454 highthroughput sequencing of 16 S rRNA gene amplicons showed that soil bacterial abundance and diversity were relatively higher in DFA compared to those in NIA and IA, and microbial community composition varied in these three areas. At the family level, those groups in Deltaproteobacteria and Methanomicrobia that might have many Hg methylators were also showed a higher relative abundance in DFA, which might be the reason for the higher MeHg production in these areas. Overall, our results suggested that seasonally water level fluctuations can enhance the microbial abundance and diversity, as well as MeHg production in the TGR.

关键词： Water level fluctuation zone Three Gorges Reservoir Soil Microbial communities Methylmercury Methylators

Refining mercury emission estimations to the atmosphere from iron and steel production

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Journal of Environmental Sciences 2016年第5期28卷 1-3页

作者： Yongmin wang Guangliang Liu dingyong wang Yong Cai College of Resource and Environment Southwest University Institute of Environment and Health Jianghan University Department of Chemistry and Biochemistry Southeast Environmental Research Center Florida International University

Due to its long-range transport in the atmosphere,mercury is a pollutant of global concern with health risks to humans and ecosystems worldwide（Li et al.,2012;Lindqvist et al.,1991;Liu et al.,2012a;Tang et al.,2016;wang et al.,2015;Shao et al.,2016）.Atmospheric mercury,mainly from emission from various natural and anthropogenic sources and re-emission of previously released mercury built up in surface soils and oceans,

关键词： Mercury Emission Iron and steel production Anthropogenic sources

选区激光熔化成形NiTi合金工艺参数对表面粗糙度的影响规律

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表面技术 2024年第9期53卷 200-208页

作者：王俊伟贺定勇吴旭王国红北京工业大学材料科学与工程学院北京100124

目的针对选区激光熔化(SLM)制备NiTi形状记忆合金表面粗糙度难以满足实际应用要求,通过优化工艺参数(激光功率、扫描速度、扫描间距)以有效地降低表面粗糙度以及研究各工艺参数对表面粗糙度的影响规律。方法采用L16正交阵列的田口模型... 详细信息

目的针对选区激光熔化(SLM)制备NiTi形状记忆合金表面粗糙度难以满足实际应用要求,通过优化工艺参数(激光功率、扫描速度、扫描间距)以有效地降低表面粗糙度以及研究各工艺参数对表面粗糙度的影响规律。方法采用L16正交阵列的田口模型设计选区激光熔化制备NiTi样品的工艺参数,通过对表面粗糙度信噪比值进行统计方法分析以及样品表面形貌的表征,研究不同工艺参数对表面粗糙度的影响程度以及影响机理,最终优化出制备低表面粗糙度的工艺参数组合。结果在激光功率为20 W和30 W时,NiTi粉末不能够充分熔化造成熔道不连续,使得样品表面起伏增大,粗糙度值最大到7.8μm;增大激光功率到40W和50W时,粉末充分熔化,样品表面形貌明显改善;在相同功率下,扫描速度从200mm/s增加到500mm/s时,样品的粗糙度值也随之增大。结论工艺参数对表面粗糙度影响的重要性顺序依次为激光功率、扫描速度、扫描间距;最终优化出的工艺参数组合为激光功率50W、扫描速度200mm/s、扫描间距0.07mm,并在该工艺参数下制备的样品表面粗糙度值为1.38μm,与模型预测的值1.43μm接近,相差仅为9.97%。

关键词：选区激光熔化 NiTi形状记忆合金田口方法表面粗糙度工艺优化

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