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    2019, Volume 26 Issue 6
    30 November 2019
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    Determination of tetracyclines and their degradation products in soil using ultra-performance liquid chromatography-tandem mass spectrometry.
    2019, 26(6): 1-6. 
    DOI: 10.13745/j.esf.sf.2019.10.2

    Abstract ( 225 )   PDF (1625KB) ( 144 )  
    We developed a method for simultaneous determination of tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC), doxycycline (DC) and their metabolites in soil by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) detection. The antibiotics were extracted using mixed solvent of acetonitrile and EDTA-Mcllvaine buffer solution and separated and purified by HLB solid phase extraction column. The purified antibiotics were detected by UPLC-MS/MS with ES(+) ionization and quantified in the multiple reaction monitoring (MRM) mode. Within 0.0010.5 mg·kg-1 range, we found a good linear relationship (R2>0.99) between the peak areas and concentrations of TCs and their metabolites, with limits of detection (LOD) and limits of quantification (LOQ) reaching 1.08515.780 and 3.61742.526 μg·kg-1, respectively. At the three addition levels of 0.05, 0.1 and 0.5 mg·kg-1, the average recovery rates for TCs and their metabolites in soil were 62.1%87.6%, with relative standard deviation (RSD) of 2.35%13.42%, except for ATC and EATC (<30%). This method is effective and meets the sensitivity, accuracy and precision demands for detecting residues of TCs and their metabolites in soil.
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    Simultaneous determination of seven fluoroquinolones in sewage sludge by high performance liquid chromatography with fluorescence detection
    CHEN Li,JIA Chunhong,LIU Bingjie,JING Junjie,ZHAO Ercheng,YU Pingzhong,HE Min
    2019, 26(6): 7-12. 
    DOI: 10.13745/j.esf.sf.2019.10.1

    Abstract ( 170 )   PDF (1004KB) ( 88 )  
    We have developed an analytical method for simultaneous determination of seven fluoroquinolones(FQs)in sewage sludge based on solid-phase extraction and high performance liquid chromatography with fluorescence detection (HPLC/FLD) in this study to monitor the FQ contents and levels in sewage sludge. The homogenized sludge sample was subjected to pH 3 phosphate buffer/acetonitrile (1∶1, V∶V) solution treatment, then loaded onto an Oasis HLB solid phase column after vortexing and eluted with methanol solvent. The FQs in the extract were detected by HPLC/FLD with acetonitrile and 0.1% formic acid as the mobile phase, and quantified using external standards. The standard curves for all the compounds were linear over the concentration ranges of 0.005 to 1.0 mg/L with R2 equaling 0.99270.9998. The spiked recoveries at 0.05, 0.5 and 1.0 mg/L levels ranged between 78.3%106.4%, with relatives standard deviations (RSD) ranging between 3.68%12.06%(N=5). The limit of detection (LOD) was between 0.0010.01 mg/kg, and the limit of quantification (LOQ) ranged between 0.00460.0384 mg/kg. We used this method to analyze seven FQs in sewage sludge collected from three sewage treatment plants in Beijing. and found the FQ concentrations to be from ND to 1.09 mg/kg in tested samples.
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    Enantioselective biodegradation and carbon isotope fractionation of myclobutanil in tea orchard soils
    LIU Bingyue,ZHANG Dongdong,HE Ling,ZHU Youfeng
    2019, 26(6): 13-18. 
    DOI: 10.13745/j.esf.sf.2019.2.11

    Abstract ( 180 )   PDF (2696KB) ( 80 )  
    We studied the dissipation of chiral triazole fungicide myclobutanil in four tea orchard soils with different cultivating ages by enantiomeric fractionation analysis(EFA) and compound-specific isotope analysis(CSIA). The dissipation of myclobutanil in soils followed first order kinetics with half-lives ranging from 28.4 to 70.5 days. Enantioselective degradation occurred in all tea orchard soils where(+)myclobutanil was preferentially degraded. The dissipation half-life and enantiomer fraction of myclobutanil were significantly lower in 50year than in 100, 20, and 2year tea orchard soils (P<0.05), while degradation half-life and enatioselectivity were significantly correlated with sand and silt contents (P<0.05), respectively. We used the logarithmic forms of the Rayleigh equation in evaluating the carbon isotope enrichment factors for various soils and established the biodegradation assessment model. The biodegradation rates of myclobutanil evaluated by both enantiomeric and isotopic fractionation analysis were consistent with the observed degradation rates.
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    Characteristic analysis of methyl orange adsorption on microplastics in water
    SONG Huan,LUO Ximing,ZHANG Li,HE Baonan,LI Jiawei,WANG Yipeng
    2019, 26(6): 19-27. 
    DOI: 10.13745/j.esf.sf.2019.7.1

    Abstract ( 415 )   PDF (5080KB) ( 164 )  
    Taking methyl orange (MO) as target pollutant and microplastics as carrier, we compared the adsorptive capacities of four typical plastic materials including common plastic polypropylene (PP), common engineering plastic nylon (PA), polyformaldehyde (POM) and special engineering plastic polytetrafluoroethylene (PTFE) in adsorption kinetics and isothermal adsorption experiments. We characterized PA before and after adsorption by scanning electron microscopy (SEM), specific surface area testing (BET), micro-Raman spectroscopy (Raman), and Zeta potential and attenuated total reflection Fourier transform infrared spectrum (ATR-FTIR). We investigated the effects of plastics materials and PA particle size on MO adsorption to explore likely adsorption mechanisms. The adsorptive capacities of microplastics for MO were obviously different for different plastic materials, among which PA had the largest adsorptive capacity of 7.39 mg/g. The adsorption process for PA included initial fast and subsequent slow reactions following two-stage second order kinetics. The results of isothermal adsorption experiments showed heterogeneous chemical adsorption of MO on PA. For different kinds of microplastics, the adsorptive capacity differences were mainly due to electrostatic effect and formation of intermolecular hydrogen bond. The particle size of microplastics was negatively correlated with the adsorptive capacity for MO (R2=0.995, P<0.05), which was closely related to the effective adsorption sites provided by microplastics. This study provided a basis for the scientific evaluation of the complicated behavior of microplastics and their capabilities, as carriers, of removing pollutants from the environment.
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    Effects of subcellular Cd accumulation in root cell wall on Cd transfer and translocation from soil to tobacco cultivars
    LEI Liping,DUAN Shuhui,ZHOU Zhicheng,WANG Meng,CHEN Shibao
    2019, 26(6): 28-34. 
    DOI: 10.13745/j.esf.sf.2018.12.13

    Abstract ( 172 )   PDF (1140KB) ( 79 )  
    Root cell wall is the first barrier to the transfer and translocation of Cd from soil to plants. To understand the mechanism of Cd transfer and translocation by tobacco cultivars affected by subcellular Cd accumulation and binding forms in root cell walls, we investigated the bioconcentration factor (BCF) and transfer factor (TF) of Cd in roots, shoots and leaves of twelve tobacco cultivar species in pot experiments. We determined the subcellular Cd accumulation characteristics and binding forms in root cell walls using in vivo bioseparation technology. We then studied the relationship between Cd uptake and translocation by tobacco plants and subcellular Cd accumulation and binding forms in root cell walls. The results showed significant difference (P<0.05) in BCFs of Cd in roots, shoots and leaves among the tested tobacco cultivars. For example, the Cd concentrations in roots ranged from 3.13 to 7.10 mg/kg, a maximum 2.27 fold variation; the Cd concentrations in tobacco leaves ranged from 3.29 to 9.93 mg/kg, a maximum 3-fold variation. Similarly, the TFs of Cd from root to leaf varied from 0.50 to 3.17, a maximum 6.34 fold change among cultivars. Our analysis indicated that the insoluble forms of Cd, binding to phosphate (Cd(PO4)n)or hemicellulose (FHAC-Cd), were the main binding forms of Cd in plant roots. The results further showed that Cd concentrations in root cell walls increased significantly after removing pectin while decreased sharply after removing hemicelluloses. We found negative correlation (P<0.05) between root-to-leaf TFs and Cd contents of cell walls after removing pectin; e.g., cultivar K346 had the highest Cd content but lowest root-to-leaf TF among the cultivars. The results implied that hemicelluloses bind most of insoluble forms of Cd in root cell walls, impeding the long distance migration and translocation of Cd from soil through xylem to the above ground parts of tobacco plants.
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    Current status of and discussion on farmland heavy metal pollution prevention in China
    CHEN Shibao,WANG Meng,LI Shanshan,ZHENG Han,LEI Xiaoqin,SUN Xiaoyi,WANG Lifu
    2019, 26(6): 35-41. 
    DOI: 10.13745/j.esf.sf.2019.8.6

    Abstract ( 826 )   PDF (1348KB) ( 575 )  
    Soil is the foundation for sustainable agricultural development. After nearly 40 years of rapid economic expansion and intensive agricultural production, the problems of soil pollution and soil environmental quality deterioration in Chinas farmlands have gradually come into focus. At present, the heavy metal pollution in farmlands has become increasingly serious and poses a potential threat to agricultural product safety. In this paper, we first summarized the current status and characteristics of heavy metal pollution in farmland soils, and sources of heavy metal pollution in farmlands and research advances in soil remediation in China. It showed that (1) in general, the rate of heavy metal contamination exceeding safety standards in farmland soils is relatively high, but contamination is mostly light; (2) among the heavy metals, Cd, As, Hg, Pb and Cr are the five major health risk elements in contaminated farmland soils, especially Cd, while ecologically hazardous elements Ni, Cu and Zn, pose relatively low environmental risk; (3) in general, the characteristics of the pollution distribution indicates pollution is more serious in south than in north and in east than in west; and (4) the pollution trend shows gradual heavy metal transfers from industrial to agricultural sources, from suburbs to rural areas, and from soil contamination to food chain pollution. Next, we did bibliometric analysis of the hotspots and research trend of heavy metal pollution prevention and control of farmland pollution in China during the past 30 years. According to the analysis, researches of pollution prevention and control started around 2000 and entered a rapid development stage after 2009. The research hotspots mainly included heavy metal pollution monitoring, soil environmental quality assessment, heavy metal-contaminated soil remediations etc. And in the last 10 years, remediation technologies have changed from single to multi-technique applications. We then evaluated the general remediation procedures and the techniques for the safe utilization of heavy metal polluted farmland soils at different pollution levels and for the control of high-risk polluted soils. Finally, we discussed the current problems in heavy metal pollution prevention in farmlands in China and prospects for key research fields. We put forward a technical system for farmland heavy metal pollution prevention and control based on combining heavy metal source and environmental risk control measures to provide references for future research planning and technology development for the prevention of heavy metal pollution in China's farmlands.
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    In vitro assessment of the effectiveness and health risks of using different washing reagents in arsenic removal from soil
    YUE Changsheng,DU Huili,PENG Ben,CUI Yanshan
    2019, 26(6): 42-48. 
    DOI: 10.13745/j.esf.sf.2019.11.30

    Abstract ( 179 )   PDF (2845KB) ( 95 )  
    Arsenic (As) pollution in soil has become a serious environmental issue in China. Soil washing is an effective way to remediate soil As pollution. In this paper, we selected three As contaminated soils and two environmentally friendly washing regents (KH2PO4 and oxalic acid) to explore the effectiveness of different washing regents on As contaminated soils. We then conducted two in vitro experiments (by the physiologically based extraction test (PBET) and in vitro gastrointestinal (IVG) methods) to explore soil As bioaccessibility. The results showed that both KH2PO4 and oxalic acid had various soil As removal capacities, and oxalic acid had a higher As removal rate of 54.3% on average. The soil As bioaccessibility determined by PBET was higher than that by the IVG method, and higher after KH2PO4 than oxalic washing. Therefore, compared with oxalic acid, KH2PO4 washing may increase human health risk from As contaminated soil. Our study showed that different in vitro methods can yield different assessments of different washing regents. Therefore, a conservative in vitro method should be selected for each washing regent to evaluate the bioaccessibility of soil As and its associated health risks from washing.
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    Hydrochemical characteristics and salinization causes of shallow groundwater in Caofeidian, Tangshan City
    HOU Guohua,GAO Maosheng,DANG Xianzhang
    2019, 26(6): 49-57. 
    DOI: 10.13745/j.esf.sf.2019.8.10

    Abstract ( 301 )   PDF (3976KB) ( 237 )  
    In order to find out the hydrochemical characteristics and salinization causes of shallow groundwater in Caofeidian area, we collected different types of water samples such as river water, underground fresh water, brackish water, salt water, brine, rainwater and seawater in the study area. We analyzed the chemical composition and ions ratio, Piper diagram, Gibbs diagram, hydrogen and oxygen isotope composition and 14C dating results of water samples. The results showed that the shallow groundwater included the phreatic water in the Holocene sedimentary layer and the faint confined water in the Late Pleistocene sedimentary layer, which were not originally enclosed in the strata but formed in the middle and late Holocene. The results also showed that there were freshwater, brackish water and salt water quality types for the phreatic water from alluvial fan to coastal plain and estuary. The salt water and brine are the main faint confined water quality types. Groundwater hydrochemistry in the frontal alluvial fan, reclamation area, and estuary and coastal plain are mainly controlled by rock weathering, seawater mixing, and evaporation/crystallization respectively. The salinization process of shallow groundwater in Caofeidian is mainly caused by repeated dissolution, by atmospheric precipitation and river water for many periods, of sea salt crystallized during the transgression and retreat period since the late Pleistocene. The salt in phreatic water of the estuary and reclamation area is mainly derived from modern seawater intrusion.
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    An overview of quantification of groundwater recharge in sponge city construction
    KANG Hongzhi,CHEN Liang,GUO Qizhong,LIAN Jijian,HOU Jie
    2019, 26(6): 58-65. 
    DOI: 10.13745/j.esf.sf.2019.8.7

    Abstract ( 232 )   PDF (1207KB) ( 183 )  
    By changing the conditions of underlying surface to delay rainfall convergence rate and accumulate rainwater resources, sponge city construction plays a key role in reducing urban rainwater surface runoff and mitigating urban internal sputum. During sponge city construction, increasing rainwater infiltration volume and using rainwater to replenish groundwater are important methods of improving rainwater resource utilization and mitigating urban water shortage. In view of the problems in quantification of groundwater recharge in sponge city construction, we summarized the quantification methods and introduced the basic principles, advantages, disadvantages and the application of each method to provide a reference for evaluating the effect of groundwater recharge in sponge city construction in China.
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    The indicative effect of soil fractal structure on its hydraulic properties
    WANG Yanyan,HE Yujiang
    2019, 26(6): 66-74. 
    DOI: 10.13745/j.esf.sf.2019.5.38

    Abstract ( 157 )   PDF (1695KB) ( 162 )  
    Understanding the hydraulic properties of soil is key to ecological hydrological simulation, agricultural water management and environmental monitoring. However, soils are extremely complex due to its spatial variability, which makes the determination of its physical properties, specially hydraulic properties very difficult. Often, test results are random and demand substantial manpower and material resources to acquire, yet soil property is difficult to describe accurately. In this report, based on a comprehensive analysis of more than 30 research methods for quantifying soil hydraulic properties, we summarized the advantages and disadvantages of using fractal theory to study soil physical properties, and analyzed the relationship between fractal theory and soil hydraulic properties. We aimed to explore the prospects and advantages of using soil fractal structures in hydraulic property determination. The results show that (1) it is feasible to use fractal analysis to study soil structure quantitatively; (2) fractal structural analysis can reveal hydraulic properties and provide a scientific basis for quick and accurate characterization of water distribution in soils at different scales; and (3) use of known soil hydraulic properties can inversely reveal soil structure effectively.
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    Evaluation of the efficiency of remediation of Cd contaminated soil by earthworm based on the rate of Cd reduction in wheat grain and changes in Cd bioavailability in soil experiment
    LIU Tuo,WANG Meng,CHEN Shibao
    2019, 26(6): 75-81. 
    DOI: 10.13745/j.esf.sf.2019.10.5

    Abstract ( 203 )   PDF (1125KB) ( 114 )  
    In this study, we evaluated the efficiency of remediation of two kinds of Cd contaminated soils (fluvo-agvic soil in Henan Province and cinnamon soil in Hebei Province) by earthworm (Eisenia fetida) in pot experiment, taking into consideration the rate of Cd reduction in wheat grain, bioavailable Cd in DTPA-extracted fraction and rate of Cd removal from soil. The results showed that Cd uptake by wheat was significantly reduced by the application of 0.5% or 1.0% earthworm(live earthworm over dry soil). Compared with control, the addition of earthworm resulted in an increase of wheat yield by 35.5%62.7%, while the rate of Cd reduction in wheat grain ranged between 31.1% and 43.5%. We believe the decreased Cd uptake and re-distribution of Cd in wheat due to earthworm were responsible for decreasing Cd content in wheat grain. The 0.5% and 1.0% earthworm could significantly reduce the soil DTPA-Cd concentration (P<0.05) by 29.1%40.8%, benefiting the transformation of Cd from bioavailable to solid forms. The removal rate of soil Cd (6.05%11.88%) was much higher than that found in the control (P<0.05), indicating earthworm has excellent potential in remediation of Cd contaminated soil. In conclusion, adding low concentration of earthworm to Cd contaminated soil played an important role in lowering Cd soil content and Cd uptake by wheat and wheat grain, which is of great significance for remediating Cd contaminated soil while ensuring the safety of agricultural products.
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    Assessing the efficiencies of remediation of Cd contaminated soil by bone charcoal and seaweed fertilizer in pot and field experiments
    WANG Meng,CHEN Shibao,LI Shanshan,LI Xiaoyue,ZHENG Han,MENG Nan
    2019, 26(6): 82-88. 
    DOI: 10.13745/j.esf.sf.2019.8.5

    Abstract ( 158 )   PDF (1587KB) ( 89 )  
    In this study, we evaluated the efficiencies of remediation of Cd contaminated soil by bone charcoal (BC) and seaweed fertilizer (SF) simultaneously in pot and field experiments by determining the Cd reduction rates (%) for wheat, maize, sorghum grain and tobacco leaves, the DTPA-extracted fraction of Cd in soil and remediation marginal efficiency (ME). The results indicated that Cd uptake by and translocation in different crops were significantly reduced (P<0.05) by the application of soil amendments. In field experiment, compared with control (CK), the Cd reduction rates for crop grain or tobacco leaves were 16.2%39.8%. Amendment application led to increase of crop productivity by 12.3%38.6%. The amount of increase depended on crop species; in this study wheat yield had the largest increase after BC application. Adding biofertilizer promoted the formation of large aggregates with higher Cd load by mass, and increased soil pH by 0.430.77 units compared with control. We believe the re-distribution of Cd in soil aggregates and increased soil pH due to amendments were responsible for immobilizing soil Cd and alleviating its phytotoxicity. The remediation marginal efficiency for the test soil ranged from 3.99% to 14.74%, with the highest ME observed for BC followed by SF treatments. In pot experiment, different amendments had bigger remediation effects than in field validation experiment, which might be due to larger root system in field soil limiting the remediation efficiency of amendments.
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    Molybdenum immobilization efficiency of two kinds of organic waste materials for molybdenum contaminated agricultural soils
    WANG Xiaoqing,QU Yang,WANG Guofeng,TIAN Wenjie
    2019, 26(6): 89-94. 
    DOI: 10.13745/j.esf.sf.2019.10.4

    Abstract ( 147 )   PDF (1561KB) ( 102 )  
    The aim of this study was to find potential ways of immobilization or remediation of molybdenum (Mo) contaminated agricultural soils. We employed industrial by-products including include biosolid and manure as amendments for Mo contaminated soils in the mining area. We evaluated the effectiveness efficiency of the two amendments on Mo immobilization by measuring the amount of extractable Mo in soils and Mo uptake by plants. The results demonstrated that, after 60 days of incubation, both amendments decreased the extractability of Mo in contaminated soils and demonstrated Mo immobilization efficacy. The decrease, however, was not significant compared to the control treatment, with manure performing better than biosolid. Both biosolid and manure could decrease Mo uptake by the shoots of alfalfa and ryegrass while increase their biomass at the same time. Therefore, we recommended that, for Mo contaminated soils remediation, the two by-products used in this study can each be applied alone or used in combination with other inorganic amendments to treat light to moderately Mo-contaminated soils.
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    Effects of root agent and water stress on wheat root elongation and Cd uptake and translocation in heterogeneous Cd contaminated soil
    LEI Xiaoqin,WANG Meng,ZHENG Han,LI Shanshan,CHEN Shibao
    2019, 26(6): 95-102. 
    DOI: 10.13745/j.esf.sf.2019.10.6

    Abstract ( 197 )   PDF (1499KB) ( 83 )  
    We investigated the influence of root agent and water stress on root elongation of wheat, and Cd uptake and translocation by wheat, in heterogeneous Cd-contaminated soil. We prepared heterogeneous Cd contaminated soils at three soil depths (06, 712 and 1318 cm) using rhizobox method. In a whole growth culture experiment, we studied the effect of root agent at three addition levels (0.1%, 0.2% and 0.4%), and the effect of three water stress treatments (60%, 50% and 40% MWHC (maximum water holding capacity)), on Cd uptake and translocation by wheat. The results indicated that root growth of wheat, compared with control, was enhanced by both treatments which significantly increased the total root length (cm) and root surface (cm2). In detail, the total root length in the subsoil (1318 cm depth) increased by 63.2%205.9% and 69.1%91.2% by root agent and water stress treatments, respectively. Root agent application promoted the wheat tillering numbers and increased the biomass of wheat grain by 5.6%50.3%. In terms of Cd uptake by wheat, the result showed that, except the 40% MWHC water stress treatment (WS3), Cd concentrations in shoots and grain of wheat were significantly decreased (P<0.05) by both treatments. Compared with control, the decreases ranged in 24.0%41.5% and 23.0%42.7%, respectively, with the best effect observed at the 0.4% additional level for root agent. The effect of different treatments on the Cd decrement in wheat grain followed the order of RA3≈RA2>WS2≈RA1≈WS1>WS3. Based on the above results, we concluded that root agent and water stress treatments can be recommended for remediation of field soils contaminated by heterogeneous heavy metals.
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    Effects of intercropping ten herbaceous plants on lead uptake by and accumulation in water spinach
    MENG Nan,WANG Meng,LI Shanshan,LI Xiaoyue,ZHENG Han,CHEN Li, CHEN Shibao
    2019, 26(6): 103-111. 
    DOI: 10.13745/j.esf.sf.2019.2.10

    Abstract ( 178 )   PDF (1809KB) ( 104 )  
    In this study, we conducted a pot experiment to investigate the effects of various intercropping patterns on lead (Pb) uptake by and accumulation in water spinach (the major crop) compared with monoculture. We used ten different herbaceous cultivars, including Gaodan Grass, Sultan Grass, Pennisetum, Ryegrass, Lactucaindica, Chicory, Grain Amaranth, Alfalfa, Clover and Vetch, as intercropping plants. The results showed that intercropping Ryegrass, Lactucaindica, Chicory, Grain Amaranth, Alfalfa, Clover and Vetch significantly increased the shoot biomass of water spinach by 15.79%84.75%(P<0.05) compared with monoculture (the control). In water spinach shoot under different intercropping modes, the Pb content was 7.1115.36 mg/kg, Pb bioconcentration factor (BCF) ranged from 0.024 to 0.051, and Pb transfer factor (TF) from root to shoot ranged between 0.240 and 0.470. After intercropping Gaodan Grass, Sultan Grass, Lactucaindica, Chicory and Grain Amaranth, the shoot Pb content and accumulation in water spinach decreased by 24.39%41.46% and 65.36%75.06%, respectively, compared with monoculture. Moreover, the exchangeable Pb content in rhizosphere soil of water spinach significantly decreased by 4.47%9.09%, while the soil pH increased by 0.32%2.74%. The shoot Pb contents of the ten tested intercropping herbs followed the order of Chicory>Ryegrass>Lactucaindica>Gaodan Grass>Sultan Grass>Vetch>Alfalfa>Pennisetum>Clover>Grain Amaranth. The total Pb accumulation in plants per pot under different intercropping modes was 0.5602.108 mg/pot, in which 10 intercropping treatments achieved 1.733.76 fold increase over that of monoculture. The results indicated that intercropping Gaodan Grass, Sultan Grass, Lactucaindica, Chicory and Grain Amaranth and water spinach effectively decreased its Pb uptake and accumulation and simultaneously enhanced the overall Pb accumulation capacity of soil in the whole system, which is an ideal outcome in intercropping remediation.
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    Effects of different agronomic practices on Cd uptake by tobacco plant and on tobacco quality under field conditions
    DUAN Shuhui,CHEN Shibao,LI Xiaoyue,XIAO Yansong,SHAN Xuehua, DENG Xiang,LIAO Yahua,LIU Yongjun,ZHOU Zhicheng
    2019, 26(6): 112-117. 
    DOI: 10.13745/j.esf.sf.2018.12.14

    Abstract ( 125 )   PDF (1123KB) ( 91 )  
    The purpose of this study was to explore the influence of different agronomic practices on Cd uptake by tobacco cultivars and on tobacco growth. We selected two kinds of Cd-polluted soil from southern tobacco planting area (paddy soil and yellow mud) as test objects and Yunyan 87 as test cultivars for this study. We carried out field plot experiment to evaluate the effects of increasing application of potassium dihydrogen phosphate, zinc sulfate, potassium humate and lime on soil available Cd, tobacco leaf Cd, soil fertility index, economic characters and chemical composition of tobacco. The results indicated that this practice significantly decreased both Cd bioeffectiveness and accumulation in soil compared with control. These agronomic measures reduced available Cd in soil and Cd content in tobacco leaves by 10.4%25.5% and 20.39%43.47%, respectively, following the ordered of potassium dihydrogen phosphate>potassium humate>zinc sulfate≈lime in effectiveness. Increasing application of lime improved soil pH by 0.240.51 units but decreased soil fertility and affected tobacco growth. Increasing application of potassium humate, whereas, increased urease and phosphatase activities as well as organic matters, cationic exchange capacity and available nitrogen in soil. It also significantly increased the potassium content in cured tobacco leaf while decreasing its sugar content, resulting in more balanced chemical composition.
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    Study of the effects of intercropping different hyperaccumulator and accumulator plants on Cd uptake and transportation by maize
    HUO Wenmin,ZHAO Zhongqiu,WANG Li,ZOU Rong,FAN Hongli
    2019, 26(6): 118-127. 
    DOI: 10.13745/j.esf.sf.2018.12.15

    Abstract ( 225 )   PDF (1723KB) ( 150 )  
    In order to study the characteristics of heavy metal Cd absorption and transportation due to intercropping maize and Amaranthus mangostanus L., Lolium perenne L. and Solanum nigrum L. under Cd contamination conditions, we selected accumulators suitable for maize intercropping and achieved remediation of heavy metal contaminated soil. In this paper, we used the Cd contaminated brown clay from Henan Province as test soil. In pot experiments, we studied the mechanism of Cd accumulation, absorption and transportation due to intercropping hyperaccumulator S.nigrum and accumulators Lolium perenne L. and Amaranthus mangostanus L., based on the changes of Cd contents in various organs of maize and changes of enrichment coefficient, translocation coefficient, total Cd in soil and available Cd content. The results showed that (1) intercropping significantly decreased Cd contents in above ground parts of maize (P<0.05), with maximum decrease in maize grain, where the Cd contents decreased by 67.6%, 75.7% and 79.9% under intercropping Amaranthus mangostanus L., Lolium perenne L. and S.nigrum, respectively; (2) compared with moncropping, intercropping the three plants decreased the Cd enrichment factor in maize by 49.3%, 39.7% and 68.5%, respectively; and (3) intercropping S.nigrum decreased the Cd transfer factors in maize by 27.5% and 24.2% compared with Amaranthus mangostanus L. and Lolium perenne L., respectively, and the difference reached a significant level. Safety value calculation for daily Cd uptake indicated that after intercropping treatments, the total Cd content should be less than 2.26 mg·kg-1 and effective Cd content lower than 0.88 mg·kg-1. Therefore, intercropping ameliorates Cd exposure risk for maize consumption in the contaminated farmland. In conclusion, intercropping Amaranthus mangostanus L., Lolium perenne L., S.nigrum and maize could inhibit both Cd uptake by maize and Cd transfer from maize roots to shoots or specially roots to grain. This scheme of intercropping not only reduces Cd accumulation in maize and ensures the safety and high quality of maize planting, it also achieves the purpose of soil remediation.
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    Vicennial implementation of geochemical survey of land quality in China
    LI Kuo,PENG Min,ZHAO Chuandong,YANG Ke,ZHOU Yalong,LIU Fei,TANG Shiqi,YANG Fan,HAN Wei,YANG Zheng,CHENG Xiaomeng,XIA Xueqi,GUAN Tao,LUO Jianlan,CHENG Hangxin
    2019, 26(6): 128-158. 
    DOI: 10.13745/j.esf.sf.2019.8.25

    Abstract ( 1278 )   PDF (11721KB) ( 490 )  
    The geochemical survey of land quality project launched in 1999 is a new national geochemical mapping project, succeeding the regional geochemistry-national reconnaissance project in China. The project has since made significant contributions in supporting governmental actions in soil pollution prevention and control, land resource management, major agricultural legislation and precision poverty relief—expanding greatly its role of geological service. We provided here a historical review on the projects background, organization, main progress, survey methodology development, analysis and testing technology improvement and quality control scheme. We made a comprehensive summary of the projects achievements in the overview of the geochemical status of national cultivated land, environmental qualities of soils in provincial capital cities and sediments in nations main freshwater lakes, and changes of soil organic carbon pools in the main agricultural areas of China in the past 20 years. We then gave an all-around introduction of the applications of survey data in land management, soil pollution prevention and control, agricultural planting structural adjustment, poverty relief, endemic disease prevention and control, and explorations for oil & gas and metallic minerals. Finally, we offered a prospective view on the future developmental trend of geochemical survey of land quality regarding innovative survey technology, new evaluation methods and integration of survey and research.
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    Epigenetic geochemical dynamics and driving mechanisms of distribution patterns of chemical elements in soil, Southwest China
    CHENG Hangxin,PENG Min,ZHAO Chuandong,HAN Wei,WANG Huiyan,WANG Qiaolin,YANG Fan,ZHANG Fugui,WANG Chengwen,LIU Fei,ZHOU Yalong,TANG Shiqi,LI Kuo,YANG Ke,YANG Zheng,CHENG Xiaomeng,CHEN Ziwan,ZHANG Hua,M
    2019, 26(6): 159-191. 
    DOI: 10.13745/j.esf.sf.2019.11.28

    Abstract ( 353 )   PDF (21709KB) ( 474 )  

     The surface layer of the Earth is a complex system made of interacting and communicating components such as mountains, rivers, forests, farmlands, lakes, grasses, etc. The interaction and mutual feedback of chemical elements in Earths surface layer can drive changes in their distribution patterns. In this paper, we studied the driving mechanism and process of interaction of the distribution patterns of macroelements, probiotics, halogens, and heavy metals in soils in Southwest China based on a systematic land quality geochemical survey at scale 1∶250000. The results showed that the parent material determines the natural state of chemical elements in land resources; the epigenetic geochemical dynamics process reshapes the distribution patterns of chemical elements in surface soil; biogeochemical processes drive the evolution trends of land quality; and strong human activities, such as mining, disrupts the natural evolution of elemental distribution patterns. By establishing an epigenetic geochemical dynamics theory, one can construction a knowledge system for the Earths surface layer and promote technological innovation in comprehensive geochemical investigation of land resources.

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    Some thoughts on the classification of soil environmental quality for agricultural land: taking risk control of Cd in potato producing area of Guizhou as an example
    SONG Jing,XU Genyan,LUO Yongming,GAO Hui,TANG Wei
    2019, 26(6): 192-198. 
    DOI: 10.13745/j.esf.sf.2019.10.3

    Abstract ( 247 )   PDF (1268KB) ( 239 )  
    By compilation of data from field sampling, pot experiment and literature, we evaluated the suitability of the existing national standards (GB 156182018 and GB/T 367832018) for the classification of soil environmental quality in potato producing areas of Guizhou. The results showed that both soil Cd standards were overly stringent as, for example, these for potatoes grown in mining areas were more likely to exceed food standard. Here, we summarized the inadequacy of the existing sampling methods for soil-crop synchronized monitoring and proposed a sampling theory-based Decision Unit-Multi Increment Sampling method (DUMIS) for soil-crop synchronized monitoring and remediation verification. We proposed that the criteria for safe soil utilization should be derived on a site-specific basis using bioavailable fractions. In order to facilitate the evaluation of soil environmental quality and safety for the agricultural production regions of China, we suggested that further research is needed regarding the use of DUMIS in soil-crop synchronized monitoring and bioavailable fractions based criteria for safe utilization of mild to moderately contaminated soils.
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    Pollution load and health risk assessment of heavy metals in road-deposited sediment in the urban-rural fringe of Beijing
    LI Haiyan,WANG Yaosen,ZHANG Xiaoran,YAN Lei,WU Liyuan,JIN Yi, CUI Ru,YANG Zhichao
    2019, 26(6): 199-206. 
    DOI: 10.13745/j.esf.sf.2019.7.2

    Abstract ( 159 )   PDF (2157KB) ( 149 )  
    Increasing urban development in China has caused increasingly serious heavy metal pollution in urban runoff. Road-deposited sediment (RDS) is an important carrier of heavy metals. In this study, we selected the urban-rural fringe of Beijing as the research area to evaluate the pollution load and assess the health risk of heavy metals (As, Cd, Cr, Cu, Mn, Pb, Zn). The results showed that the average concentrations of As, Cd, Cr, Cu, Pb and Zn, except Mn, had exceeded the background values. The mean concentration of Cd was 3 times the background value, and the mean concentration of Cr was 4 times the background value. Under runoff scouring, the pollution load of Cr was 34 times that of other metals, the highest in all study areas. Exposure model calculation showed that the average daily non-carcinogenic exposure values of heavy metals for three exposure pathways followed the order of ingestion > dermal contact > inhalation. Thus ingestion is the main exposure pathway. We detected non-carcinogenic risk for children in the area around the intersection of Luqiu and Huang Goose Road, and low non-carcinogenic risk for adults in the whole area. We found relatively low carcinogenic risk in each study area, as the areas total carcinogenic risk of heavy metal contamination via respiratory exposure pathways was lower than the environmental safety threshold.
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    Soil quality assessment based on risk control of heavy metal pollution in soil: a case study of an industrial city in China
    LI Yufeng,ZHAO Zhongqiu,ZHU Peitian,CHEN Yong,LI Qian,YUAN Ye,LI Xuezhen
    2019, 26(6): 207-215. 
    DOI: 10.13745/j.esf.sf.2019.8.2

    Abstract ( 251 )   PDF (2464KB) ( 239 )  
    In recent years, social and economic developments in China have caused increasingly serious problems in soil quality in agricultural land affected by heavy metal pollution. However, most soil quality evaluation reports have seldom considered the soil pollution or soil environmental quality issue and largely ignored the effect of soil pollution risk on soil quality evaluation. In this study, we developed a method to introduce soil pollution parameters into the soil quality evaluation system. Taking a typical county-size industrial city as an example, we assessed the soil fertility status based on soil physicochemical properties. We classified the types of risk control of heavy metal pollution in soil in the study area and incorporated the classification into the soil fertility status evaluation system by establishing a piecewise function. Finally, we evaluated the soil quality in agricultural land by our method. The results showed that the coefficient of soil physicochemical property in the study area varied as AP>SEC>TP>SOC>CEC>TN>pH, while soil fertility tended to increase with decreasing terrain and increasing rivers. The high fertility areas were mainly distributed in the plains of the northwest and northeast, whereas low fertility areas, surrounded by fertility transitional areas, were in the southeastern hilly and mountainous areas and the lowland in the west. Classification of the types of risk control of soil pollution in agricultural land showed that, for the 8 heavy metals tested, at least 88.89% samples for Cd and 98.61% for Cr belonged to the priority protection category, and 11.11% samples for Cd and 1.39% for Cr met the safe use standard, indicating heavy metal pollution was dominated by Cd. Soil quality assessment showed that the overall distribution of soil quality was similar to that of soil fertility; however, soil contamination risk evaluation expanded the low-quality soils in the southwestern study area eastwards, resulting in a denser distribution of lower-quality soils in the southeast. The above research results demonstrated that by introducing classification of the soil pollution risk control types, soil fertility correction should generally be reduced, and the spatial distribution of native soil fertility status may also be modified to a certain extent.
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    Supercritical fluid crystals in igneous rocks and the implications
    LUO Zhaohua,YANG Zongfeng,SU Shangguo,LIU Cui,JIANG Xiumin
    2019, 26(6): 216-227. 
    DOI: 10.13745/j.esf.sf.2019.9.16

    Abstract ( 147 )   PDF (3795KB) ( 250 )  
    In the prevailing igneous theory, the term magma is acquiescently considered synonymous to natural melt. Consequently, all mineral crystals in an igneous rock are crystallized from melt and can be named as melt crystals. However, many observations imply that crystals crystallized from supercritical fluid phases also occur in igneous rocks and can be classified as supercritical fluid crystals or simply fluid crystals. In this paper, based on the analysis of three typical instances, we proposed that fluid crystals not only can form directly in a supercritical fluid phase, but also can form in the melt phase generated by the supercritical fluid through concentration. By all accounts, the precondition for fluid crystals is that the magmatic fluid attains to the supersaturation state. In order to satisfy this fundamental condition, the transmagmatic fluid process and/or rapid ascent of the magma are required. Based on previous investigations of melt-fluid equilibrium condition, and considering the dependencies of melt viscosity on volatile content and of magma ascent rate on magma viscosity, we found a coupling relationship between transmagmatic fluid process and magma ascent. This relation can be used to explain the nonlinear behavior of a magma system. Thus, it is very important to study fluid crystals as (1) it provides a new approach to reconstruct the fluid condition of a magma system; (2) it reveals the deviation level of a magma system from the ideal state; (3) it adds a new constraint to the inversion of dynamic processes of a magmatic system; (4) it provides new mineralogical indicators for recognizing ore-causal intrusions and assessing ore producing potentials; and (5) it provides solutions to some long-standing ambiguous issues in the prevailing igneous theory, such as solubility of magmatic volatile components, reactivation of frozen magma and specificity of magmatic metallogenesis.
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    Mineralogical evidence for fluid activities in the metallogeny of the Talnakh magmatic Cu-Ni sulfide deposit in Norilsk, Russia
    JIANG Junyi,SU Shangguo,WANG Jingjiao
    2019, 26(6): 228-243. 
    DOI: 10.13745/j.esf.sf.2019.3.12

    Abstract ( 135 )   PDF (4581KB) ( 115 )  
    The composition and mechanism of intrusion and accumulation of “sulfide slurry” are still under debate in the study of magmatic copper-nickel sulfide deposits. In this report, based on the idea of the newly proposed “magmatic conduit metallogenic system”, we studied the ore-bearing olivine-gabbronorite in the Talnakh Cu-Ni sulfide deposit in Norilsk, Russia. We found two types of main rock-forming minerals that have significantly different trace elemental compositions. Here, we focus on the characteristics of plagioclase. Based on the distribution pattern of trace elements, all plagioclase can be divided into two types. The type I plagioclase consists of albite-bytownite and is highly enriched in LILEs and LREEs and largely depleted in HFSEs. It is assembled as sulfide droplet and obviously altered by the fluid, indicating the sulfide droplets are likely filled with fluid. The type II plagioclase is enriched in LREEs, largely depleted in HFSEs, and consists of andesine-bytownite. It shows weak alteration by fluid, suggesting that it is formed by normal crystallization. Thus, we believe that “sulfide slurry” contained a large amount of fluid during the intrusion process and should be called “melt-fluid”. This study provides new evidence to support the theory that fluid activities played an important role in the enrichment and migration of sulfides in Cu-Ni sulfide deposits.
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    Magnetite characteristics of the Yushiwa iron deposit in Wu‘an, Hebei Province and its indication significance to the genesis of iron deposit
    HOU Xiaoyang,SU Shangguo,YANG Yueyue
    2019, 26(6): 244-256. 
    DOI: 10.13745/j.esf.sf.2019.5.13

    Abstract ( 265 )   PDF (3852KB) ( 119 )  
    The genesis of skarn iron deposit has long been controversial involving mainly the contact metasomatism and ore magma genetic models. The Yushiwa iron deposit is one of the major skarn iron deposits in the Handan-Xingtai area, Hebei Province. It contains three types of magnetite ores in the Jianshan section, on which a detailed study should help to resolve the genetic controversy. Magnetite in the main ore body of the Yushiwa iron deposit in the lower part of the profile is characterized by high Ti content. However, magnetite veins in the upper crystalline limestone have high Si (w(SiO2)>1%) content. And magnetite in monzonite has a transitional composition. Through major and trace elemental analysis of the three types of magnetite, we found gradual decreasing Ti and increasing Si and Mg contents in magnetite in the main ore body in the lower Yushiwa iron deposit to magnetite veins in the upper crystalline limestone. High silicon magnetite forms euhedral crystal and coexists with calcite in equilibrium. Its formation has fluid involvement, making it possible a fluid crystal mineral. The magnetite FeV/Ti discrimination diagram shows a magmatic genesis of the iron ore body of the lower Yushiwa iron deposit, and a hydrothermal genesis of magnetite veins in monzonite and crystalline limestone. The iron deposit experienced a continuous transition from magma genesis of the lower part to hydrothermal genesis of the upper part. According to these characteristics, we believe that the iron ore slurry contains a large amount of fluid to form the “iron bearing melt-fluid”. Under fluid overpressure, the “iron bearing melt-fluid” rises rapidly from the magmatic conduit to arrive at the shallow part of the crust, forming high-temperature high-Ti magnetite in the lower part and transitioning to high-Si magnetite of fluid crystal in the upper part of the deposit. We call this metallogenic model a magmatic conduit metallogenic system.
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    Origin and source of the Hannuoba alkaline basalts
    CUI Xiaoliang,SU Shangguo,SONG Chen,JIANG Junyi,HEI Huixin,WU Yue
    2019, 26(6): 257-270. 
    DOI: 10.13745/j.esf.sf.2019.9.22

    Abstract ( 406 )   PDF (5432KB) ( 287 )  
    The Hannuoba basalts, erupted in the Neogene in northern North China, contain not only complete rock outcrops but also widespread ultramafic xenoliths and a variety of high-pressure megacrysts. The Daihuanggou profile, one of the better exposed profiles of the Hannuoba basalts generation, can be divided into the upper three layers and base from top to bottom. Petrographic observations showed that these basalts contained 1%5% of xenocrysts and trace of phenocrysts. The peridotite xenoliths were spinel-iherzolite. They were slightly depleted in LREE and had no fractionation of LREE and HREE, which is consistent with primary mantle xenoliths after some partial melting. Through mineralogical analysis of phenocrysts and xenocrysts, such as olivine, pyroxene and plagioclase in the Daihuanggou basalt, we concluded that the compositional changes in phenocrysts or xenocrysts are caused by the rapid rising basalt after mixing with the decomposition product of mantle peridotite. Compared to the native melt in equilibrium with lherzolite, the Mg# (52.062.7), CaO (7.3%8.5%), Ni ((82192)×10-6) and Cr ((65192)×10-6) contents were lower. The REE patterns for basalts showed right-wing type enrichment; HFSE (Nb, Ta and Zr) and LILE (Ba and Sr) were also enriched, with δEu=1.011.05 and δCe=0.951.02. Trace elemental ratios Ba/Rb and Rb/Sr showed that magmatic source might have been fluid metasomatism. According to trace elemental compositions, this series of rocks is mainly controlled by partial melting, where large scale fractional crystallization does not occur, and the residual source contains garnet. The analysis suggests that the basalt magma should be a primary rather than an evolved magma. The process that affects the formation of the entire magma may be partial melting rather than fractional crystallization. Based on current published experimental results and theoretical petrology analysis, the Hannuoba basalts are in equilibrium with pyroxenite, and the magma source contains mainly clinopyroxene and garnet and possibility a small amount of olivine.
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    Complexity and dynamics of vesicle shapes of pumices formed in the three Tianchi volcano eruptions
    PENG Nian,ZHU Xiaoyan,LIU Yongshun,NIE Baofeng,LI Su
    2019, 26(6): 271-280. 
    DOI: 10.13745/j.esf.sf.2019.9.18

    Abstract ( 124 )   PDF (2598KB) ( 99 )  
    In the process of an explosive eruption, the vesicles of volcanic pyroclasts record the information of volatile exsolution and bubble expansion and coalescence. The localization characteristics of bubble size, shape, number density and spatial distribution are important to inferring the dynamic conditions of volcanic eruption. On the basis of field geological work on pumices from the three Tianchi volcano eruptions (yellow pumice from the 50000 year BP eruption, gray-white pumice from the millennium eruption, and black pumice from the 1668 Baguamiao Stage eruption), we studied the fluid dynamics of bubble growth in volcanic conduit under non-linear dynamics of volcanic eruption. The result reveals that the combined effects of magmatic viscous force and surface tension controlled magmatic decompression and bubble growth. According to quantitative analysis of vesicle structures of pumices, we further studied the vesicle parameters of the three pumices from Tianchi volcano eruptions. The results show that the capillary number (Ca) of gray-white pumice from the millennium eruption was 253, which is higher than that of yellow pumice from the 50000 year BP eruption (Ca=94) or of black pumice from the Baguamiao Stage eruption (Ca=111), indicating the millennium eruption had obviously undergone compositional change possibly related to the injection of mantle-derived basic magma. The irregular vesicular shape parameter (1-Ω) of yellow pumice from the 50000 year BP eruption was 0.098, which is higher than that of the two pumices from the later two eruptions (0.052 and 0.064, respectively). It means that the relaxation period of dynamic equilibrium decreased in the Tianchi volcanic system, or the growth of pumice bubbles was weakened by dynamic and rheological modifications, either way it provides a reference for further study of eruptive activity in the Tianchi volcano. The magnitudes of the capillary number (102) and vesicle irregular shape parameter (10-1) for the three stages of pumices also confirmed for the first time the Plinian or Ultraplinian eruption of the Tianchi volcano.
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    The formation mechanism of pyroclastic lava and its significance for the identification of volcanic rock faces: a case study from Qingshen gasfield, Songliao Basin
    NIU Huapeng,WANG Guiwen,XIAN Benzhong,FU Jianwei,JIAO Xiaoqin,LI Hongjuan
    2019, 26(6): 281-288. 
    DOI: 10.13745/j.esf.sf.2019.9.21

    Abstract ( 154 )   PDF (4697KB) ( 128 )  
    Based on reservoir closely related with the different lithology and facies, looking for superior volcanic reservoir focuses on the identification of volcanic rock facies and subfacies. In this paper, on the base of geological data accumulated in the study of volcanic rocks basin, the formation mechanism of pyroclastic lava in Qingshen gasfield of Songliao Basin and its significance for the identification of volcanic rock facies and log facies were discussed. Studies have shown that the pyroclastic lava have generally five genetic types such as the pyroclastic flow, the foam lava flow, the stream broken oneself, the near-surface magma cryptoexplosion, and the remelting type which are unique petrology and log response characteristics. According to the formation mechanism, petrology and FMI characteristics, the above different five genetic types respectively belong to the hot pyroclastic flow subfacies of eruption facies, the erupting-flowing facies between explosive facies and effusive facies, effusive facies, cryptoexplosive breccia subfacies of volcanic vent facies, volcanic neck subfacies of volcanic vent facies or facies around crater. The results of the study contribute to the accurate identification of volcanic rock facies and subfacies, and the effective forecast of the high quality reservoirs.
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    An early warning model system for predicting meteorological risk associated with geological disasters in the Longnan area, Gansu Province based on the information value method
    LUO Hongdong,LI Ruidong,ZHANG Bo,CAO Bo
    2019, 26(6): 289-297. 
    DOI: 10.13745/j.esf.sf.2019.11.1

    Abstract ( 237 )   PDF (4627KB) ( 142 )  
    Early warning of meteorological risk associated with geological disasters is difficult and it is presently the focus of geological disaster prevention and management. The Longnan area in Gansu Province is one of the most hazardous areas in China with major casualties and property losses caused by natural disasters. This study is aimed to accurately predict the meteorological risk associated with geological disasters in Longnan. By using ArcGIS software, we divided the research area into 250 m×250 m raster and selected 9 factors to assess the areas susceptibility of geological environment by the information value method. Combining effective precipitation and susceptibility we constructed an early warning model system which was verified and tested by 6 historical rainfall events. The system has a statistical prediction accuracy of 83.42%, which is an improvement for the study area. We show that the geoenvironmental susceptibility division, based on the information value method, is objective and sensible. And a second generation early-warning system that integrates underlying surface and meteorological factors should have higher prediction accuracy and applicability in the study area.
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    Trace element compositions in PM2.5 after the action for comprehensive control of air pollution in Beijing
    SHAO Longyi,CHANG Lingli,ZHANG Mengyuan,LI Jie,LI Yaowei,LI Wenjun,FENG Xiaolei
    2019, 26(6): 298-308. 
    DOI: 10.13745/j.esf.sf.2019.11.31

    Abstract ( 187 )   PDF (1612KB) ( 116 )  
    We investigated by ICP-MS the trace elemental compositions of PM2.5 in Beijing after the implementation of the ‘action plan’ for comprehensive control of air pollution. The results showed that PM2.5 mainly contained 7 trace elements, Zn, Mn, Ba, Pb, Cr, Cu and Ti, with Zn ranked the highest in content. The water-soluble form of Zn, Cd, Tl, Cs or Rb accounted for more than 80% of its total content in PM2.5, revealing that most trace elements occur water-soluble in fine particles. Interestingly, trace elemental contents (10-6) in PM2.5 samples decreased with increasing PM2.5 pollution levels, whereas, mass concentrations (ng·m-3) increased with increasing pollution levels, the same trend as PM2.5 mass concentration. It indicated that the content of trace elements in PM2.5per unit mass is only related to the composition of particles, not the concentration of particles. The trace elements in PM2.5 during the sampling period were mainly from soil dust (48.27%), combustion sources and industrial emissions (16.16%) and vehicle brake and tire wear (10.03%), followed by automobile exhaust (5.84%), construction dust (4.88%) and other sources (3.68%). Compared with the results before the action for comprehensive air pollution control, the mass concentration of trace elements in PM2.5 after the action decreased significantly, with the greatest decrease of 80.3% at high pollution level.
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    Academic controversy on the mechanism and driving forces of plate movement
    WAN Tianfeng,LI Sanzhong,YANG Weiran,LIANG Guanghe,MAO Xiaoping,LIU Yinhe,YU Wenhui,CHEN Zhigeng,DING Weiping,HU Baoqun,FU Hong,et al
    2019, 26(6): 309-319. 
    DOI: 10.13745/j.esf.sf.2019.11.20

    Abstract ( 1302 )   PDF (1745KB) ( 723 )  
    The present day human understanding of the Earth is still superficial, and the issue of geodynamics is still exploratory both foreign or domestically. The 10th major scientific question, out of total of 125, identified by the Science magazine in 2005 was “How does the Earths interior work”, noting that the source of the earths driving force had not yet been resolved. The book, “Chinese disciplinary Developmental strategy-Plate Tectonics and continental Dynamics” published in 2017, believed that although the plate tectonics theory has achieved great success, the theory still has three major inherent problems, namely the plate driving force, plate origin and plate theory when applied to continents. Among them, the driving mechanism of plate motion is the most important and urgent problem to be solved.
    The seminar is divided into two parts: reporting of main views, and discussion of the controversy. In the reporting section, five speakers expound their views on the driving force mechanism. Liang Guanghe puts forward a new theory of continental drift. Through analyses of a wealth of data, he believes that there are many problems in the traditional model of seafloor spreading being the driving force. He cites many geological and geophysical observations that the persistent driving force for continental drift is not the sustained seafloor spreading but continuous magma upwelling behind and beneath the continental plate in a spontaneous chain reaction. Wan Tianfeng proposes a new driving mode based on meteorite impact theory, believing that the traditional seafloor spreading conveyor model cannot explain why the continental drift speed is much larger than the mantle convection velocity. He hypothesizes that the meteorite impact induces mantle diapirs to promote continental plate movement. Tang Chunan puts forth an Earth cracking theory. He believes that the accumulation and release of thermal energy inside the Earth make the lithospheric mantle going through alternating hot and cold cycles in the geological history. According to Mao Xiaopings analysis, only the circumferential-direction stress is strong enough to be the proposed earth driving force that promotes the plate motion, that the circumferential-direction stress is released at the weak point of the lithosphere to promote the relative movement of the crust, and that the long time unexplained “crustal abnormal pressure” is in fact circumferential-direction stress, but the tectonic force and collision force that can be independent of gravity do not exist.
    During discussion and contention, everyone is free to speak on the driving force of crustal movement. Liang Guanghe acknowledges that the meteorite impact proposed by Wan Tianfeng may better explain the initial driving force of the supercontinent break-up, but he does not agree that meteorite impact can provide the driving force for continuous continental drift. Because, he explains, taking the northward drift of the Indian Plate as an example, the huge viscous resistance of the mantle requires numerous meteorites to hit the back of the Indian plate at fixed points before the Indian plate can continue to drift. Tang Chunan points to the Earths pot-cover effect: the upper mantle has a cold and hot period, and the crust will drift on a large scale during the hot period. According to the mechanical mechanism, the mid-ocean ridge and transform fault cannot be caused by seafloor spreading, but should be a fracture system caused by continental drift. Finally, Yang Weiran concludes that meteorite impact is an important factor; tectonic movements on the earth can be attributed to opening-closing movements; and seafloor spreading and continental drift exist, and terrane tectonics is scientific.
    The consensus reached at the seminar is that there are indeed large-scale horizontal movements in the mainland continent, but the traditional mantle convection conveyor belt drive model has many problems in its inconsistency with the observation facts, therefore it is necessary to re-recognize the driving mechanism and the driving force. Most of the seminar participants express doubts or even opposition to the plate subduction argument. They consider the driving force should come from gravity and internal heat of the Earth, and more in-depth researches are required to understand their interactions.
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    Epigenetic geochemical dynamics and driving mechanisms of chemical elemental distribution patterns in soil in Southwest China
    CHENG Hangxin, PENG Min, ZHAO Chuandong, HAN Wei, WANG Huiyan, WANG Qiaolin, YANG Fan, ZHANG Fugui, WANG Chengwen, LIU Fei, ZHOU Yalon
    2019, 26(6): 320-354. 
    DOI: 10.13745/j.esf.sf.2020.2.29

    Abstract ( 206 )   PDF (21709KB) ( 118 )  

     The Earth's surface is a complex system involving mutual interactions of its many components, including mountains, rivers, forests, farmlands, lakes and grasses. The interaction and mutual feedback of chemical elements in Earths surface layer can drive changes in chemical elemental distribution patterns. In this study, we evaluated the mechanisms and interactions driving the distribution patterns of macroelements, probiotics, halogens and heavy metals in soils in Southwest China, based on a systematic geochemical land-quality survey at a scale of 1250000. The results showed that the parent material determines the natural state of chemical elements in land resources. Epigenetic geochemical dynamics reshapes the distribution patterns of chemical elements in top soil; biogeochemical processes drive the evolutionary trends of land quality; and human activities, such as mining, disrupt the natural evolution of chemical elemental distribution patterns. The establishment of an epigenetic geochemical dynamics theory allows the construction of a framework for understanding the Earths surface layer and promoting technological innovations for the comprehensive geochemical investigation of land resources.

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