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Mercury in leaf litter in typical suburban and urban broadleaf forests in China

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Journal of Environmental Sciences 2011年第12期23卷 2042-2048页

作者： Zhenchuan Niu Xiaoshan Zhang zhangwei wang Zhijia Ci Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

To study the role of leaf litter in the mercury （Hg） cycle in suburban broadleaf forests and the distribution of Hg in urban forests, we collected leaf litter and soil from suburban evergreen and deciduous broadleaf forests and from urban forests in Beijing. The Hg concentrations in leaf litter from the suburban forests varied from 8.3 to 205.0 ng/g, with an average （avg） of （49.7 ± 36.9） ng/g. The average Hg concentration in evergreen broadleaf forest leaf litter （50.8 ± 39.4） ng/g was higher than that in deciduous broadleaf forest leaf litter （25.8 ± 10.1） ng/g. The estimated Hg fluxes of leaf litter in suburban evergreen and deciduous broadleaf forests were 179.0 and 83.7 mg/（ha·yr）, respectively. The Hg concentration in organic horizons （O horizons）（（263.1 ± 237.2） ng/g） was higher than that in eluvial horizons （A horizons）（（83.9 ± 52.0） ng/g）. These results indicated that leaf litterfall plays an important role in transporting atmospheric mercury to soil in suburban forests. For urban forests in Beijing, the Hg concentrations in leaf litter ranged from 8.8–119.0 （avg 28.1 ± 16.6） ng/g, with higher concentrations at urban sites than at suburban sites for each tree. The Hg concentrations in surface soil in Beijing were 32.0–25300.0 ng/g and increased from suburban sites to urban sites, with the highest value from Jingshan （JS） Park at the centre of Beijing. Therefore, the distribution of Hg in Beijing urban forests appeared to be strongly influenced by anthropogenic activities.

关键词： mercury broadleaf forests leaf litter soil flux

Distribution of eight heavy metals in the inner shelf sediments of East China Sea:Risk assessments and sources analysis

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Ecosystem Health and Sustainability 2021年第1期7卷 87-101页

作者： Chunjie wang zhangwei wang Xiaoshan Zhang State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijingChina College of Resources and Environment University of Chinese Academy of SciencesBeijingChina

Although numerous studies on heavy metals(HMs)in sediments have been carried out in the East China Sea(ECS),the knowledge on the recent pollution levels of HMs in coastal region remains not well understood due to the rapid developments of urbanization in eastern *** this study,23 surface samples and 4 core samples are collected in the inner shelf of the *** average dry-weight concentrations follow the descending order of Zn,Cr,Ni,Pb,Cu,As,Cd,and Hg(103.6±26.0,42.8±12.4,37.0±9.1,34.7±11.1,19.5±10.3,15.7±11.6,0.056±0.017,and 0.041±0.017μg g^(−1),respectively).HMs concentrations share a similar spatial distribution pattern of TOC content with a decreasing trend from coastline to outer ***,HMs concentrations exhibit a decreasing trend from top to bottom sediments,especially for Hg at the open sites due to the wet and dry deposition of atmospheric Hg besides the riverine *** potential ecological risk indices(PERI)values in coastal sediments were about 2-4 times higher than those in open *** the Hg and Cd concentrations were lower by 2-3 orders of magnitude than those of other six metals,the PERI values of Hg(65.5)and Cd(52.1)were 3-40 times higher than those of *** hierarchical cluster result is consistent with the PCA result,suggesting that Hg,Cd,and As have similar sources and probably mainly originated from anthropogenic emissions.

关键词： Heavy metals spatial distribution cores environmental risk east China Sea

The soil displacement measurement of mercury emission flux of the sewage irrigation farmlands in Northern China

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Ecosystem Health and Sustainability 2019年第1期5卷 169-180,I0021页

作者： Yu Gao zhangwei wang Chunjie wang Xiaoshan Zhang Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijingChina College of Resources and Environment University of Chinese Academy of SciencesBeijingChina

Mercury fate of sewage irrigation in farmlands deserves attention with increasing scarcity of freshwater resources for agriculture in the ***-air total gaseous mercury(TGM)fluxes from four-sewage and one-fresh water irrigated farmlands were determined *** maize-wheat rotation,soil-air TGM fluxes showed patterns of both emission and deposition during different growth *** enhanced one-order of magnitude emission with increased Hg contamination from historical sewage irrigation.A linear response relationship of TGM fluxes with soil Hg concentration was found,which showed greater TGM emission potential comparing with those from forest and urban ***,the ratio of soil-air TGM flux in daytime to nighttime were 3.94 in maize-season and 3.41 in wheat-season,respectively,which were little related to the change in soil Hg ***,soil temperature and moisture,ambient-air TGM concentration all effected TGM evasion from sewage-irrigated *** data presented here suggest that evasion of TGMfromhistorical sewage irrigation farmlands with high Hg concentrations may be potential hotspots for Hg emission in atmosphere,and it was likely to underestimate Hg emissions from farmlands in existing emissions *** regionalinvestigations and process-level researches are needed to better understand role of sewage irrigation farmlands in local-global Hg-biogeochemical-cycles.

关键词： Soil-air mercury exchange flux sewage irrigation farmland maize-wheat rotation soil displacement environmental factors

Dissolved organic sulfur in streams draining forested catchments in southern China

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Journal of Environmental Sciences 2012年第4期24卷 704-710页

作者： Zhanyi wang Xiaoshan Zhang zhangwei wang Yi Zhang Bingwen Li Rolf Vogt Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China College of Ecology and Environmental Science Inner Mongolia Agricultural UniversityHohhot 010018China Department of Chemistry University of OsloP.O.BOX 1033BlindernN-0315 OsloNorway

Dissolved organic sulfur （DOS） is an important fraction for sulfur mobilization in ecosystem. In this work stream waters were sampled in 25 forested sites in southern China to study the dissolved sulfur fractions. Dissolved sulfur was fractionated into dissolved organic sulfur （DOS） and inorganic sulfate （SO]-） for 95 stream water samples. The results showed that the concentration of DOS ranged from 0 to 13.1 mg/L （average 1,3 mg/L） in all the streams, High concentrations of DOS in stream waters were found in the sites with high concentrations of sulfate. DOS constituted less than 60.1% of dissolved sulfur （average 17.9%）. Statistical analysis showed that DOS concentration was correlated with SO42- in streams waters and total sulfur in surface layer soils. The results also showed that DOS concentration in stream waters had a seasonal variation, but no trends were found with it. The implication was that the long term sulfur deposition had led the increase of the concentration and fraction of DOS in stream waters in acid rain prevailing regions

关键词： dissolved organic sulfur stream water Chinese forests sulfur deposition

Species profile and reactivity of volatile organic compounds emission in solvent uses,industry activities and from vehicular tunnels

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Journal of Environmental Sciences 2024年第1期135卷 546-559页

作者： Haimei Huang zhangwei wang Chunhao Dai Hai Wu Jia Guo Chunjie wang Xiaoshan Zhang State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Hunan Agricultural University Changsha 430106China National Institute of Metrology Beijing 100029China

A survey was conducted of the volatile organic compounds(VOCs)released from sources of solvent use,industry activities and vehicle emissions in Guiyang,a capital city of *** were collected by canisters and analyzed by *** species profiles of VOCs emitted from sources were *** showed that xylenes,ethylbenzene,acetone and dichloromethane were the characteristics species for painting,2-propanol and ethyl acetate for printing,α-pinene for solid wood furniture manufacturing,and 2-butanone for biscuit *** characteristics species could be as tracers for the sources *** most of samples from the solvent use,the benzene/toluene(B/T)ratio was less than 0.3,indicating that the ratio could be as the indicator for tracing the solvent use related *** results also suggested that the toluene/xylene(T/X)ratio be as the indicator to distinguish the VOCs sources of painting(2).Aromatics contributed the most to ozone formation potential(OFP)of most painting and non-paper printing sources,and oxygen-containing VOCs(OVOCs)were major species contributing to OFP of the sources from food production and paper *** OFP of the VOCs emissions from vehicle in tunnels and from other manufactures were dominated by both aromatics and ***α-pinene could explain 56.94%and 32.54%of total OFP of the VOCs sources from filing cabinet and solid wood furniture manufacturing,which was rarely been involved in previous studies of VOCs source profiles,indicating that the species of concern for VOCs sources are still insufficient at present.

关键词： Volatile organic compounds(VOCs) Species profile BTEX ratio Source reactivity

Thermal Stability and Strengthening Effect of Coherent Precipitates in a (FeCoNi)_(92)Al_(2.5)Ti_(5.5) High Entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1491-1500页

作者： Yuqi Liu Feng wang Songyang Chen Hui wang Zhiping Xiong Khurram Yaqoob zhangwei wang Min Song tate Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China State Key Laboratory for Advance Metals and Materials University of Science and Technology BeijingBeijing100083China National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing100081China School of Chemical and Materials Engineering National University of Sciences and TechnologyH-12Islamabad44000Pakistan

The coarsening behavior and strengthening effect of L1_(2)-Ni_(3)(Ti,Al)precipitates in a face-centered-cubic(FCC)(FeCoNi)_(92)Al_(2.5)Ti_(5.5) high entropy alloy have been systematically *** coherent L1_(2) precipitates,uniformly distributed throughout the FCC matrix,consistently retain a spherical *** coarsening rate coefficient of precipitate is determined by employing the Philippe-Voorhees(PV)model,suggesting excellent thermal ***,the elemental partitioning and compositional evolution of the L1_(2) precipitates is analyzed by atom probe tomography,which identify aluminum(Al)as the slowest diffusion species during the coarsening *** addition,the precipitation strengthening effect is quantified to ascertain the optimal size of the *** study enhances the understanding of precipitate coarsening in high entropy alloys,presenting valuable insights into their thermal stability and mechanical properties.

关键词： High entropy alloy L1_(2)precipitates Coarsening kinetics Precipitation hardening

Mercury enrichment in Brassica napus in response to elevated atmospheric mercury concentrations

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Frontiers of Environmental Science & Engineering 2017年第1期11卷 45-52页

作者： Chunhao Dai Pufeng Qin zhangwei wang Jian Chen Xianshan Zhang Si Luo College of Resources & Environment Hunan Agricultural University Changsha 410128 China Department of Atmospheric Environment Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

Mercury enrichment in response to elevated atmospheric mercury concentrations in the organs of rape （Brassica napus） was investigated using an open top chamber fumigation experiment and a soil mercury enriched cultivation experiment. Results indicate that the mercury concentration in leaves and stems showed a significant variation under different concentrations of mercury in atmospheric and soil experiments while the concentration of mercury in roots, seeds and seed coats showed no significant variation under different atmospheric mercury concentrations. Using the function relation established by the experiment, results for atmospheric mercury sources in -rape field biomass showed that atmospheric sources accounted for at least 81.81% of mercury in rape leaves and 32.29% of mercury in the stems. Therefore, mercury in the aboveground biomass predominantly derives from the absorption of atmospheric mercury.

关键词： Open top chamber Gaseous elemental mercury (GEM) Soil Mercury Brassica napus

The tension-compression asymmetry of martensite phase transformation in a metastable Fe40Co20Cr20Mn10Ni10 high-entropy alloy

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Science China Materials 2020年第9期63卷 1797-1807页

作者： Xinglong An zhangwei wang Song Ni Min Song State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Max-Planck-Institut für Eisenforschung Max-Planck-Str.1Düsseldorf 40237Germany

The microstructural evolution of a metastable face centered cubic(FCC)Fe40Co20Cr20Mn10Ni10high-entropy alloy(HEA)under both tension and compression is systemically *** results show much higher level of martensite phase transformation from FCC structure to hexagonal closed packed(HCP)structure under compression than tension,indicating a distinct tension-compression *** compressive tests underwent higher true stresses,which further provided stronger driving forces to trigger the phase transformation than those in tensile *** for the martensite phase transformation,dislocation planar slip prevails in both tension and compression,along with the occasional formation of mechanical *** slip dominates the whole tensile deformation,while both dislocation motions and martensite phase transformation play critical roles in the compressive *** martensite phase transformation is preferred to nucleate at grain or subgrain boundaries due to a medium stacking fault energy(SFE)of^20 m J m^-*** formation of HCP phase via partial dislocation emission from low-angle grain boundaries offers additional pathways for martensite phase *** study thus remarkably benefits the understanding of the deformation mechanisms of metastable HEAs.

关键词： high-entropy alloy tension-compression martensite phase transformation stacking fault energy

Effect of sterilization on barrier property of BOPET used in film-laminated steel

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Baosteel Technical Research 2017年第2期11卷 6-10页

作者： wang zhangwei XIE Long CHEN Hongxing Research Institute Baoshan Iron & Steel Co.Ltd.

High-temperature sterilization is applied when film-laminated steel is used as food-can packaging material. To study the effect of this sterilization on the barrier property of biaxially oriented polyester （BOPET） film,the water vapor transmission, thermal properties, and microstructure of BOPET that had undergone different sterilization time were analyzed. Results show that water vapor transmission is decreased by sterilization, and that with increased sterilization treatment time,the melting point and melting enthalpy of BOPET increases. Moreover, the microstructure of BOPET film also can be improved by sterilization ,in which the quantity of crystal nuclei and the crystallization density increase to form a network-like structure, which is beneficial to the barrier property of BOPET film.

关键词： film-laminated steel BOPET film sterilization barrier property crystallization