Dynamic imaging of metallic contamination plume based on self-potential data

A dynamic imaging method for monitoring self-potential data was proposed.Based on the Darcy’s law and Archie’sformulas,a dynamic model was built as a state model to simulate the transportation of metallic ions in porous medium,and theNernst equation was used to calculate the redox potential of metallic ions for observation modeling.Then,the state model andobservation model form an extended Kalman filter cycle to perform dynamic imaging.The noise added synthetic data imaging testshows that the extended Kalman filter can effectively fuse the model evolution and observed self-potential data.The further sandboxmonitoring experiment also demonstrates that the self-potential can be used to monitor the activities of metallic ions and exactlyretrieve the dynamic process of metallic contamination.

Assessment of Heavy Metals Contamination of Topsoil and Street Dust around Cement Factory in Southern Jordan

Evaluation of assessment of the metal processes governing the metals distribution in soil and dust samples is very significant and protects the health of human and ecological system. Recently, special attention has given to the assessment of metals pollution impact on soil and dust within industrial areas. This study aims to assess the metal contamination levels in the topsoil and street dust around the cement factory in Qadissiya area, southern Jordan. The levels of seven metals (namely Fe, Zn, Cu, Pb, Cr, Cd, and Mn) were analyzed using Flame Atomic Absorption Spec-trophotometer (FAAS) to monitor, evaluate, and to compare topsoil and road dust pollution values of metals of the different types of urban area. The physicochemical parameters which believed to affect the mobility of metals in the soil of the study area were determined such as pH, EC, TOM, CaCO3 and CEC. The levels of metal in soil samples are greater on the surface but decrease in the lower part as a result of the basic nature of soil. The mean values of the metals in soil can be arranged in the following order: Zn > Pb > Mn > Fe > Cu > Cr > Cd. The relatively high concentration of metals in the soil sample was attributed to anthropogenic activities such as traffic emissions, cement factory and agricultural activities. Correlation coefficient analysis and the spatial distribution of indices and the results of statistical analysis indicate three groups of metals: Fe and Mn result by natural origin, Zn, Pb, Cu and Zn result by anthropogenic origin (mainly motor vehicle traffic and abrasion of tires) while Cd is mixed origin. The higher content level values of metals of anthropogenic source in soil samples indicate that it is a source of contamination of air in the studied area. .

Metal Contamination in Field Grown Rice

[Objective] Detecting the concentration of metals （lead, cadmium and arsenic） in the rice from one test field was to provide a snapshot of the current status of metal contamination in rice, coming up with a scientific basis for further research. [Method] The research divided 15 adjacent fields into five groups. Two samples were randomly selected from each field. Metal contamination was evaluated based on GB standards and the overall pollution score （OPS）. [Result] The percentages of samples with above-standard levels of the three metals are 83.3%, 100% and 36.7%, respectively. The values of OPSs are ranged from five to seven, with Pb＇s pollution index constituting the most percentage between three metals in OPS. [Conclusion] A metal contamination in the grown rice of this test field is observed, in which Pb may be the most important factor, and Cd contents in all of the samples exceed the safety value.

Distributions and risk assessment of heavy metals in solid waste in lead-zinc mining areas and across the soil, water body, sediment and agricultural product ecosystem in their surrounding areas

To identify the root causes of heavy metal contamination in soils as well as prevent and control such contamination from its sources,this study explored the accumulation patterns and ecological risks of heavy metals like Cd and Pb in solid waste in mining areas and across the water body,sediment,soil and agricultural product ecosystem surrounding the mining areas.Focusing on the residual solid waste samples in lead-zinc deposits in a certain area of Guizhou Province,along with samples of topsoils,irrigation water,river sediments,and crops from surrounding areas.This study analyzed the distributions of eight heavy metals,i.e.,Cd,As,Cr,Hg,Pb,Zn,Cu,and Ni,in the samples through field surveys and sample tests.Furthermore,this study assessed the contamination levels and ecological risks of heavy metals in soils,sediments,and agricultural products using methods such as the single-factor index,Nemerow composite index,and potential ecological risk assessment.The results indicate that heavy metals in the solid waste samples all exhibited concentrations exceeding their risk screening values,with 60%greater than their risk intervention values.The soils and sediments demonstrate slight and moderate comprehensive ecological risks of heavy metals.The single-factor potential ecological risks of heavy metals in both the soil and sediment samples decreased in the order of Hg,Cd,Pb,As,Cu,Zn,Cr,and Ni,suggesting the same sources of heavy metals in the soils and sediments.Most of the agricultural product samples exhibited over-limit concentrations of heavy metals dominated by Cd,Pb,Ni,and Cr,excluding Hg and As.The agricultural product assessment using the Nemerow composite index reveals that 35%of the agricultural product samples reached the heavy metal contamination level,implying that the agricultural products from farmland around the solid waste dumps have been contaminated with heavy metals.The eight heavy metals in the soil,sediment,and agricultural product samples manifested high coefficients of variation(CVs),indicating pronounced spatial variability.This suggests that their concentrations in soils,sediments,and agricultural products are significantly influenced by human mining activities.Additionally,the agricultural products exhibit strong transport and accumulation capacities for Cd,Cu,and Zn.

Effect of Metal Contamination on Characteristics of Ultra-Thin Gate Oxide

The purpose of this work relates to study on the characteristics of ultra thin gate oxide (2 5nm thickness) and the effect of metal Al,Zr,and Ta contamination on GOI.The controlled metallic contamination experiments are carried out by depositing a few ppm contaminated metal and low pH solutions on the wafers.The maximum metal surface concentration is controlled at about 10 12 cm -2 level in order to simulate metal contamination during ultra clean processing.A ramped current stress for intrinsic charge to breakdown measurements with gate injection mode is used to examine the characteristics of these ultra thin gate oxides and the effect of metal contamination on GOI.It is the first time to investigate the influence of metal Zr and Ta contamination on 2 5nm ultra thin gate oxide.It is demonstrated that there is little effect of Al contamination on GOI,while Zr contamination is the most detrimental to GOI,and early breakdown has happened to wafers contaminated by Ta.

Effect of Metal Contamination on the Performance of Catalyst for Deep Catalytic Cracking Process

The effect of different metal contamination levels of catalysts for Deep Catalytic Cracking(DCC) on the distribution and selectivity of DCC products was investigated in a FCC pilot unit. The pilot test results showed that the effects of the metal contamination level of catalyst on the propylene yield,the coke yield,the LPG yield,the gasoline yield,the selectivity of low carbon olefins,and coke selectivity was significant,and that the influence of metal contamination level on the conversion and dry gas yield was minor.

Effect of loess for preventing contamination of acid mine drainage from coal waste

Acid mine drainage （AMD） that releases highly acidic, sulfate and metals-rich drainage is a serious environmental problem in coal mining areas in China. In order to study the effect of using loess for preventing AMD and controlling heavy metals contamination from coal waste, the column leaching tests were conducted. The results come from experiment data analyses show that the loess can effectively immobilize cadmium, copper, iron, lead and zinc in AMD from coal waste, increase pH value, and decrease Eh, EC, and 8024- concentrations of AMD from coal waste. The oxidation of sulfide in coal waste is prevented by addition of the loess, which favors the generation and adsorption of the alkalinity, the decrease of the population of Thiobacillusferrooxidans, the heavy metals immobilization by precipitation of sulfide and carbonate through biological sul- fate reduction inside the column, and the halt of the oxidation process of sulfide through iron coating on the surface of sulfide in coal waste. The loess can effectively prevent AMD and heavy metals contamination from coal waste in in-situ treatment systems.

Spatial Distribution and Seasonal Variations of Heavy Metal Contamination in Surface Waters of Liaohe River, Northeast China

Heavy metal pollutants are a worldwide concern due to slow decomposition, biocondensation, and negative effects on human health. We investigated seasonal and spatial variations of the five heavy metals and evaluated their health risk in the Liaohe River, Northeast China. A total of 324 surface water samples collected from 2009 to 2010 were analyzed. Levels(high to low) of heavy metals in the Liaohe River were: zinc(Zn) > chromium(Cr) > copper(Cu) > cadmium(Cd) > mercury(Hg). Spatial and seasonal changes impacting concentrations of Cu and Zn were significant, but not significant for Cr, Cd and Hg. The highest concentrations of heavy metals were: Hg at Liuheqiao, Cu at Fudedian, Zn at Tongjiangkou, Cr at Mahushan, and Cd at Shenglitang. The highest concentrations of Hg and Cr were found in the wet period, Cu and Cd in the level period, and Zn in the dry period. The surface water of a tributary was an important accumulation site for heavy metals. Health risks from carcinogens and non-carcinogens increased from upstream to downstream in the mainstream of the Liaohe River. The total health risk for one person in the Liaohe River exceeded acceptable levels. The total health risk was the greatest during the wet period and least in the dry period. Among the five heavy metals in the Liaohe River, Cr posed the greatest single health risk.

Trace Metal Contamination of Water in the Lubumbashi River Basin, Kafubu, Kimilolo and Kinkalabwamba Rivers in Lubumbashi City, Democratic Republic of Congo

Concentrations of fifteen trace metals including Aluminum （Al）, Vanadium （V）, Chromium （Cr）, Manganese （Mn）, Iron （Fe）, Strontium （Sr）, Molybdenum （Mo）, Silver （Ag）, Cadmium （Cd）, Tin （Sn）, Caesium （Cs）, Barium （Ba）, Lead （Pb）, Bismuth （Bi） and Uranium （U） were investigated in water samples collected from sixteen sampling locations in the Lubumbashi river basin and five locations in Kafubu, Kimilolo and Kinkalabwamba rivers during February, March and April 2016. Chemical analyses of the samples were carried out using ICP-MS （Inductively Coupled Plasma-Mass Spectrometer）. Water pH was determined using a pH-meter and pH values ranged from 4.2 to 7.8. The highest mean trace metal levels of water were 5,515.816 ）μg·L^-1, 166.925μg·L^-1, 3.898μg·L^-1 and 1.879μg·L^-1 for Al, Ba, Cr and U, respectively in Kashobwe river, 2,419.522 μg·L^-1 and 17.994 μg·L^-1 for Fe and Cd, respectively in Kafubu river at its confluence with Lubumbashi rivers, 1,408.136μg·L^-1 for Mn in Kafubu river 1.36 kilometer downward its confluence with Naviundu river, 222.406 μg·L^-1 and 0.092 μg·L^-1 for Sr and Cs, respectively in Kamalondo river 60 meters from the GCM-Lubumbashi （General of Quarries and Mines-Lubumbashi） smelter, 140.294μg·L^-1, 12.063 μg·L^-1 and 0.008μg·L^-1 for Pb, V and Bi, respectively in Munua river, 3.544 μg·L^-1 for Ag in Kabulameshi river, 1.49 μg·L^-1 for Mo in Kafubu river and 0.081μg·L^-1 for Sn in Tshondo river. The mean concentrations of Al, Cd, Fe, Mn and Pb in water of many rivers and the channel exceeded the maximum admissible limits of the WHO （World Health Organization）, USEPA （United States Environmental Protection Agency） and EU （European Union） drinking-water standards. Trace metal contamination of water of the studied rivers, channel and springs might be partially attributed to natural processes, unplanned urbanization, poor waste management and mostly to abandoned and ongoing mining and ore processing activities in Lubumbashi city.

Trace Metal Contamination of Water in Naviundu River Basin, Luano and Ruashi Rivers and Luwowoshi Spring in Lubumbashi City, Democratic Republic of Congo

Aluminum （AI）, Vanadium （V）, Chromium （Cr）, Manganese （Mn）, Iron （Fe）, Strontium （Sr）, Molybdenum （Mo）, Silver （Ag）, Cadmium （Cd）, Tin （Sn）, Caesium （Cs）, Barium （Ba）, Lead （Pb）, Bismuth （Bi） and Uranium （U） concentrations were investigated in water samples from fifteen sampling locations in Naviundu river basin, Luano and Ruashi rivers and Luwowoshi spring in Lubumbashi city during February, March and April 2016. Chemical analyses of the samples were carried out using Inductively Coupled Plasma-Mass Spectrometer. Water pH was determined using a pH-meter and mean pH values ranged from 4.2 to 5.8. The highest mean levels of Al （5,961.954 μg·L^-1）, Pb （472.287 μg·L^-1）, V （21.014 μg·L^-1）, Cr （8.185μg·L^-1）, U （4.163μg·L^-1） and Bi （0.012 μg·L^-1） were recorded in Chemaf （Chemicals of Africa） hydrometallurgical plant effluent, those of Mn （29,714.593 μg·L^-1）, Sr （374.377μg·L^-1）, Cd （11.358μg·L^-1） and Cs （0.107μg·L^-1） in Naviundu river at Cimenkat （Katanga＇s Cement Factory） exit, those of Fe （14,258.9 μg·L^-1） and Ba （307.641μg·L^-1） in Luano river and those of Ag （2.669 μg·L^-1）, Mo （0.559 μg·L^-1） and Sn （0.325 μg·L^-1） were respectively noted in Foire channel, Naviundu river under bridge on Kasenga road and Kalulako river. The concentrations of Cd in Naviundu river at Cimenkat exit （11.358 μg·L^-1）, Chemaf bydrometallurgical plant effluent （9.697μg·L^-1）, Naviundu river under bridge on De Plaines Avenue （6.95 μg·L^-1） and Kalulako river （3.229 μg·L^-1）, Pb concentrations in Chemaf hydrometallurgical plant effluent （472.287 μg·L^-1） as well as the AI, Fe and Mn concentrations recorded in most waters in this study exceeded the WHO （World Health Organization） maximum permissible limits for drinking water. The metal contamination of waters of the studied rivers, channel and spring might be partially attributed to natural processes, unplanned urbanization and poor waste management, and mostly to abandoned and ongoing mining and ore processing activities in Lubumbashi city.

Assessment of Cu, Pb and Hg Contamination in Bottom Sediments Of Surface Water in XuZhou

Pollution of heavy metals Cu,Pb and Hg is assessed using geo-accumulation index in this paper. The result shows that the bottom sediments of surface water in Xuzhou is polluted by these heavy metals to deferent degrees, of which the Jinma River is the most serious, and then the Kuihe River, the abandoned Yellow River, and the Jinghang Canal. The Yunlong Lake has also been polluted by Hg. The three kinds of heavy metals in the order of concentration is Hg>Cu>Pb. The pollution degree and the type of element is closely related with industrial structure in Xuzhou.

Comparative Study of the Efficacy of Metal Removal from Contaminated Aqueous Solutions by Solid Bidentate Ligands&Liquid Plant Materials

Heavy metal contaminated water sources pose serious health risks for humans,animals,and plants.Exposure to and ingestion of heavy metals have been associated to liver,kidney,and brain function.Objective:The aim of this research is to comparatively examine the metal removal efficacy of three solid bidentate chemicals and four plant materials.Study Design&Methods:Standard solutions of zinc(II)and lead(II)ions with concentrations of 1,000 ppm were respectively treated with OA(Oxalic Acid),dibasic bidentate ligands(sodium hydrogen phosphate and sodium carbonate).Then,the solutions were placed on a shaker for 15 h,centrifuged,and the supernatant was analyzed using ICP-AES(Inductively Coupled Plasma-Atomic Emission Spectrometry).Results:All the solid bidentate adsorbents were very effective in removing zinc and lead(>90%).However,more lead than zinc was removed across all adsorbents except for lemon where equal percent of zinc and lead(49%)were removed.OA and Na2HPO4 removed about equal amount of lead(>99%).The plant materials(SP(Spinach),bell pepper and GBP(Green Bell Pepper)),respectively and preferentially removed more lead(98.9%,98.3%,81.5%)than zinc(91.7%,46%,46%).Conclusion:Although plant materials have gained attraction for the remediation of heavy metal,however,some bidentate chemical ligands such as OA,sodium carbonate and sodium hydrogen phosphates are even more effective in removing these metals from contaminated water.Furthermore,heavier metals are preferentially removed than lighter metals.

Effect of amendments on growth and metal uptake of giant reed(Arundo donax L.) grown on soil contaminated by arsenic,cadmium and lead

The effects of five amendments such as acetic acid（AA）, citric acid （CA）, ethylenediamine tetraacetic acid （EDTA）, sepiolite and phosphogypsum on growth and metal uptake of giant reed （Arundo donax L.） grown on soil contaminated by arsenic （As）, cadmium （Cd） and lead （Pb） were studied. The results showed that the shoot biomass of giant reed was enhanced by 24.8% and 15.0%, while superoxide mutase and catalase activities slightly varied when adding 5.0 mmol/kg CA and 2.5 mol/kg EDTA to soil as compared to the control, respectively. The concentrations of As, Cd and Pb in shoots were remarkably increased by the addition of 2.5 mmol/kg AA and CA, 5.0 mmol/kg EDTA, and 4.0 g/kg sepiolite as compared to the control. The accumulations of As and Cd were also significantly enhanced in the above condition, while the shoot Pb accumulation was noticeably enhanced by amending with 4.0 g/kg sepiolite and 8.0 g/kg phosphogysum, respectively. The results suggested that AA, CA and sepiolite could be used as optimum soil amendments for giant reed remediation system.

Effects of Red Mud on the Remediation of Pb, Zn and Cd in Heavy Metal Contaminated Paddy Soil

[Objective] To study the remediation efficiency of red mud on Pb, Zn and Cd in the heavy metal contaminated paddy soil of mine area, to clarify its remediation mechanism and fertilizer efficiency on heavy metal contaminated soil. [Method] The soil incubation experiment was conducted to study the effect of red mud on the pH values and electrical conductivity （EC）, and the remediation efficiency of red mud on lead （Pb）, zinc （Zn） and cadmium （Cd） in heavy metal contaminated soil. [Result] Red mud addition reduced the content of exchangeable Pb, Zn and Cd in the soil significantly. Compared with the control, when incubated for 30, 60 and 90 d with the red mud dosage of 4% （W/W）, the exchangeable Pb content was decreased by 39.25%, 41.38% and 50.19%; exchangeable Zn content was decreased by 49.26%, 57.32% and 47.16%; and exchangeable Cd content was decreased by 19.53%, 24.06% and 25.70%, respectively. The application of red mud had significant impact on the share of Pb, Zn and Cd contents in five forms, and different amounts of red mud application all reduced the proportion of exchangeable Pb, Zn and Cd to the total Pb, Zn and Cd. In addition, the proportion of exchangeable Pb, Zn and Cd to total Pb, Zn and Cd decreased with the increasing amount of red mud addition. [Conclusion] The study provided references for reasonable application of red mud and reduction of heavy metal pollution in paddy soil.

Study Progress in Remediation of Soil Contaminated by Heavy Metals and Its Application Prospect

Flax is an ideal crop for remedying soil contaminated by heavy metals. It has high tolerance to heavy metals and strong adsorption to heavy metals. Through properly using or adjusting external conditions such as regulator, moisture, fertilizer, microorganisms, and pH value, it is able to improve ability of flax to absorb, trans- fer, and accumulate heavy metals. To improve the ability of flax in remediating heavy metal contaminated soil, it is recommended to strengthen cultivation of flax varieties and screening of germplasm resources, actively carry out studies on tech- nologies of fax remedying heavy metal contaminated soil, implement large-scale and mechanized planting of flax, and promote control of heavy metal contaminated soil.

Mechanical properties of anti-seepage grouting materials for heavy metal contaminated soil

Cement-based composite grouting materials were used to construct grouting cutoff wall for heavy metal contaminated soil in non-ferrous metal mining areas. Cement, fly ash, and slag as principal ingredients were mixed with water glass in different ways to produce three composite grouting materials. In order to investigate the effect of water glass mixing ratio, Baume degree, fly ash and slag contents on the mechanical properties of the composite grouting materials, particularly their gel time and compressive strength, the beaker-to-beaker method of gel time test and unconfined compressive strength test were conducted. In addition, the phase composition and microstructure of the composite grouting materials were analyzed by the X-ray diffraction（XRD） and scanning electron microscope（SEM） techniques. The test results show that their gel time increases when water glass mixing ratio and Baume degree increase. The gel time increases dramatically when fly ash is added, but decreases slightly if fly ash is partly replaced by slag. When the mixing ratio of water glass is below 20%, their compressive strength increases with the increases of the ratio; when the ratio is above 20%, it significantly decreases. The compressive strength also tends to increase as Baume degree increases, and improves if fly ash and slag are added.

Human Health Risks from Exposure to Heavy Metals of Suspended Particulate Matter around the Tongon Gold Mine, Côte d’Ivoire

The Tongon mine, the largest gold mine in C?te d’Ivoire, has been in operation since April 2010. However, to our knowledge to date, no study has been conducted on metallic contamination in suspended particulate matter (PM10 and PM2.5) where there is a lack of information on the carcinogenic and non-carcinogenic risk to human health associated with the exposure of populations in the Tongon area to these pollutants. The general objective of this study is to evaluate the level of contamination of PM10;PM2.5 by heavy metals and their impact on the health of populations exposed to these pollutants in the Tongon gold mine area. The sampling and measurement of suspended particulate matter (PM10 and PM2.5) were done using a MiniVol TAS passive air sampler. Heavy metal concentrations were determined by inductively coupled plasma mass spectroscopy (Nex ION 2000 ICP-MS, USA). The results indicate that the average concentrations of suspended particles (PM2.5 and PM10) obtained are all above the recommended exposure limits. In addition, among the heavy metals contained in the suspended particles, the concentrations of arsenic and nickel are high and all above the standard limit values. The assessment of the health risks related to the inhalation of PM10 particles reveals that their inhalation over a long period could cause a carcinogenic risk.

Effects of Glomus mosseae on the toxicity of heavy metals to Vicia faba

A glasshouse pot experiment was conducted to investigate effects of the arbuscular mycorrhizal fungus Glomus mosseae on the growth of Vicia faba and toxicity induced by heavy metals （HMs） （Cu, Zn, Pb and Cd） in a field soil contaminated by a mixture of these metals. There was also uninoculation treatment （NM） simultaneously. Mycorrhizal （GM） plants have significantly increased growth and tolerance to toxicity induced by heavy metals compared with NM plants. P uptake was significantly increased in GM plants. Mycorrhizal symbiosis reduced the transportation of HMs fi＇om root to shoot by immobilizing HMs in the mycorrhizal, shown by increasing the ratios of HMs from root to shoot. Oxidative stress, which can induce DNA damage, is an important mechanism of heavy metal toxicity. GM treatment decreased oxidative stress by intricating antioxidative systems such as peroxidases and non-enzymic systems including soluble protein. The DNA damage induced by heavy metals was detected using comet assay, which showed DNA damage in the plants was decreased by the GM treatment.

Mechanical properties of fiber and cement reinforced heavy metal-contaminated soils as roadbed filling

The treatment of contaminated soil is a crucial issue in geotechnical and environmental engineering.This study proposes to incorporate appropriate polypropylene fibers and cements as an effective method to treat heavy metal contaminated soil(HMCS).The objective of this paper is to investigate the effects of fiber content,fiber length,cement content,curing time,heavy metal types and concentration on the mechanical properties of soils.To this end,a series of direct shear test,unconfined compression strength(UCS)test,dry-wet cycle and freeze-thaw cycle test are performed.The results confirm that the appropriate reinforcement of polypropylene fibers and cement is an effective way to recycle HMCS as substitutable fillers in roadbed,which exhibits benefits in environment and economy development.

Leaching potential and changes in components of metals in two acidic ferrisols

Two acidic ferrisols, i.e., red soil （RS） and yellow red soil （YRS）, from the vicinity regions of non-ferrous ores in Hunan province of China, were leached with simulated acid rain through artificial column experiments. The results show that the total leaching mass of metals are m（Zn）〉m（Cu）〉m（Cd） from the original soils and m（Cd）〉m（Zn）〉〉 m（Cu） from the contaminated soils with external metals after leaching for 60 d continuously, leaching quantities of Cd and Zn from the contaminated red soil （CRS） are more than that from the contaminated yellow red soil （CYRS）, but for Cu, it is almost the same. The preferential fractions for leaching are mainly in exchangeable forms, and content of exchangeable forms decreases significantly in the contaminated soil profiles. The unstable fractions of Cd, Cu and Zn in the RS and YRS increase significantly with the decrease of pH value of simulated acid rain. Changes of fi, actions of external Cd, Cu, and Zn in the residual CRS and CYRS profiles are significantly affected by the acidity of acid rain, too. After leaching for 60 d continuously, Cd exists mostly in exchangeable form, Cu exists mainly in exchangeable, manganese oxide-occluded and organically bounding forms, and Zn exists in residual in CRS and CYRS profiles. Most of exchangeable Cd and Zn exist only small in surface layer （0-20 cm） and are transferred to the sub-layers, contrarily, Cu accumulates mostly in the topsoil （0-20 cm） with low translocation.