The geological characteristics and production practices of the major middle-and high-maturity shale oil exploration areas in China are analyzed.Combined with laboratory results,it is clear that three essential conditi...The geological characteristics and production practices of the major middle-and high-maturity shale oil exploration areas in China are analyzed.Combined with laboratory results,it is clear that three essential conditions,i.e.economic initial production,commercial cumulative oil production of single well,and large-scale recoverable reserves confirmed by the testing production,determine whether the continental shale oil can be put into large-scale commercial development.The quantity and quality of movable hydrocarbons are confirmed to be crucial to economic development of shale oil,and focuses in evaluation of shale oil enrichment area/interval.The evaluation indexes of movable hydrocarbon enrichment include:(1)the material basis for forming retained hydrocarbon,including TOC>2%(preferentially 3%-4%),and typeⅠ-Ⅱkerogens;(2)the mobility of retained hydrocarbon,which is closely related to the hydrocarbon composition and flow behaviors of light/heavy components,and can be evaluated from the perspectives of thermal maturity(Ro),gas-oil ratio(GOR),crude oil density,quality of hydrocarbon components,preservation conditions;and(3)the reservoir characteristics associated with the engineering reconstruction,including the main pore throat distribution zone,reservoir physical properties(including fractures),lamellation feature and diagenetic stage,etc.Accordingly,13 evaluation indexes in three categories and their reference values are established.The evaluation indicates that the light shale oil zones in the Gulong Sag of Songliao Basin have the most favorable enrichment conditions of movable hydrocarbons,followed by light oil and black oil zones,containing 20.8×10^(8) t light oil resources in reservoirs with R_(0)>1.2%,pressure coefficient greater than 1.4,effective porosity greater than 6%,crude oil density less than 0.82 g/cm^(3),and GOR>100 m/m^(3).The shale oil in the Gulong Sag can be explored and developed separately by the categories(resource sweet spot,engineering sweet spot,and tight oil sweet spot)depending on shale oil flowability.The Gulong Sag is the most promising area to achieve large-scale breakthrough and production of continental shale oil in China.展开更多
Based on the combination of core observation,experimental analysis and testingand geological analysis,the main controlling factors of shale oil enrichment in the Lower Permian Fengcheng Formation in the Mahu Sag of th...Based on the combination of core observation,experimental analysis and testingand geological analysis,the main controlling factors of shale oil enrichment in the Lower Permian Fengcheng Formation in the Mahu Sag of the Junggar Basin are clarified,and a shale oil enrichment model is established.The results show that the enrichment of shale oil in the Fengcheng Formation in the Mahu Sag is controlled by the organic abundance,organic type,reservoir capacity and the amount of migration hydrocarbon in shale.The abundance of organic matter provides the material basis for shale oil enrichment,and the shales containing typesⅠandⅡorganic matters have good oil content.The reservoir capacity controls shale oil enrichment.Macropores are the main space for shale oil enrichment in the Fengcheng Formation,and pore size and fracture scale directly control the degree of shale oil enrichment.The migration of hydrocarbons in shale affects shale oil enrichment.The shale that has expelled hydrocarbons has poor oil content,while the shale that has received hydrocarbons migrated from other strata has good oil content.Lithofacies reflect the hydrocarbon generation and storage capacity comprehensively.The laminated felsic shale,laminated lime-dolomitic shale and thick-layered felsic shale have good oil content,and they are favorable lithofacies for shale oil enrichment.Under the control of these factors,relative migration of hydrocarbons occurred within the Fengcheng shale,which leads to the the difference in the enrichment process of shale oil.Accordingly,the enrichment mode of shale oil in Fengcheng Formation is established as"in-situ enrichment"and"migration enrichment".By superimposing favorable lithofacies and main controlling factors of enrichment,the sweet spot of shale oil in the Fengcheng Formation can be selected which has great significance for the exploration and development of shale oil.展开更多
Effective detection of abnormal electricity users and analysis of the spatial distribution and influencing factors of abnormal electricity consumption in urban areas have positive effects on the quality of electricity...Effective detection of abnormal electricity users and analysis of the spatial distribution and influencing factors of abnormal electricity consumption in urban areas have positive effects on the quality of electricity consumption by customers,safe operation of power grids,and sustainable development of cities.However,current abnormal electricity consumption detection models do not consider the time dependence of time-series data and rely on a large number of training samples,and no study has analyzed the spatial distribution and influencing factors of abnormal electricity consumption in urban areas.In this study,we use the Seasonal-Trend decomposition procedure based on Loess(STL)based time series decomposition and outlier detection to detect abnormal electricity consumption in the central city of Pingxiang,and analyze the relationship between spatial variation and urban functions through Geodetector.The results show that the degree of abnormal electricity consumption in urban areas is related to geographic location and has spatial heterogeneity,and the abnormal electricity users are mainly located in areas with highly mixed residential,commercial and entertainment functions in the city.The results obtained from this study can provide a reference basis and a theoretical foundation for the detection of abnormal electricity consumption by users and the arming of electricity theft devices in the power grid.展开更多
This study is performed to know the contamination level of heavy metals on the surrounding agricultural soils at the site of Barapukuria Coal Mine Company Limited (BCMCL). Total concentrations of eight heavy metals (C...This study is performed to know the contamination level of heavy metals on the surrounding agricultural soils at the site of Barapukuria Coal Mine Company Limited (BCMCL). Total concentrations of eight heavy metals (Cu, As, Cd, Zn, Pb, Cr, Ni and Mn) were measured in that soil. To calculate the contamination level, the enrichment factor (EF), geoaccumulation index (I<sub>geo</sub>) and Hakanson potential ecological risk index were done. I<sub>geo</sub> values indicated that the study areas at all stations were suffering from moderate contamination with As. The results of enrichment factor revealed that soils in all stations were in extremely high enrichment condition by As metal. Under Hakanson potential ecological risk index, the contamination coefficient () and potential ecological risk index () were calculated. The degree of contamination at BCMCL area reflects moderate contamination. By considering the ecological risk index of a particular heavy metal, the order is as follows: Cd > As > Cu > Pb > Ni > Cr > Zn and Cd has the highest risk index and poses the greatest damage to the BCMCL area’s soil. EF, I<sub>geo</sub> values and potential ecological risk index indicate that there is considerable As and Cd pollution, mainly caused by coal mine drainage water.展开更多
The Fe, Zn, Mn and Pb concentrations in the seawater dissolved phase were investigated in the sea-surface microlayer (SML), subsurface water (SSW) and bottom water (BW) samples collected at of three mariculture ...The Fe, Zn, Mn and Pb concentrations in the seawater dissolved phase were investigated in the sea-surface microlayer (SML), subsurface water (SSW) and bottom water (BW) samples collected at of three mariculture areas of the Nanao Island ocean zone. The results showed that the SML and the BW were important compartments for these heavy metals in the mariculture areas and the concentrations varied from 23.0 μg/L to 268.0 μg/L(Fe), 11.0 μg/L to 82.2 μg/L(Zn), 1.5 μg/L to 11.0 μg/L(Mn) and 6.0 μg/L to 40.5 μg/L(Pb) in SSW, while a clear enrichment is observed in the SML, where these ranged from 27.5 μg/L to 286.5 μg/L(Fe), 13.5/lg/L to 89.0μg/L(Zn), 3.0μg/L to 12.0 μg/L(Mn) and 7.0 μg/L to 46.0μg/L(Pb). The enrichment factors were in the range of 1.07 - 1.39 which showed a slight enrichment. The average enrichment factors of Fe, Zn, Pb and Mn were 1.18, 1.13, 1.12 and 1.30, respectively. The average enrichment factors in shellfish, fish and gracilaria lemaneaformis farming areas were 1.26, 1.19 and 1.11, respectively, which showed that the surface activity was highest in the shellfish farming area. Furthermore, the heavy metals concentrations were lowest in the gracUaria lemaneaformis farming area. The results of single factor contamination index showed that the investigated areas were slightly contaminated with Zn, while the partial farming areas were seriously contaminated with Pd during a certain period of time.展开更多
PM2.5 aerosols were sampled in urban Chengdu from April 2009 to January 2010, and their chemical compositions were characterized in detail for elements, water soluble inorganic ions, and carbonaceous mat- ter. The ann...PM2.5 aerosols were sampled in urban Chengdu from April 2009 to January 2010, and their chemical compositions were characterized in detail for elements, water soluble inorganic ions, and carbonaceous mat- ter. The annual average of PM2.5 was 165 btg m a, which is generally higher than measurements in other Chinese cities, suggesting serious particulate pollution issues in the city. Water soluble ions contributed 43.5% to the annual total PM2.5 mass, carbonaceous aerosols including elemental carbon and organic car- bon contributed 32.0%, and trace elements contributed 13.8~0. Distinct daily and seasonal variations were observed in the mass concentrations of PM2.5 and its components, reflecting the seasonal variations of dif- ferent anthropogenic and natural sources. Weakly acidic to neutral particles were found for PMz5. Major sources of PM2.u identified from source apportionment analysis included coal combustion, traffic exhaust, biomass burning, soil dust, and construction dust emissions. The low nitrate: sulfate ratio suggested that stationary emissions were more important than vehicle emissions. The reconstructed masses of ammonium sulfate, ammonium nitrate, particulate carbonaceous matter, and fine soil accounted for 79% of the total measured PM2.5 mass; they also accounted for 92% of the total measured particle scattering.展开更多
In the east coast Peninsular Malaysia region,sediments are transported by several rivers from the east Malaysia into the South China Sea estuary.In the vicinity of the five river estuaries core sediments were collecte...In the east coast Peninsular Malaysia region,sediments are transported by several rivers from the east Malaysia into the South China Sea estuary.In the vicinity of the five river estuaries core sediments were collected in order to investigate rare earth elements(REEs) profile.Core sediments were divided into strata of between 2 to 4 cm intervals and prepared for analyzing by ICP-AES.REE concentrations of 54.3 μg/gr at 24–26 cm in EC4 increased to 114.1 μg/gr at 20–22 cm in EC5.The measured concentration of ...展开更多
Total suspended particulates (TSP) samples were collected using low pressure impactors (Andersen Series 20-800, USA) on typical clear, hazy and foggy days in Beijing in order to investigate the characteristics of ...Total suspended particulates (TSP) samples were collected using low pressure impactors (Andersen Series 20-800, USA) on typical clear, hazy and foggy days in Beijing in order to investigate the characteristics of size distributions and elemental compositions of particulate matter (PM) in different weather conditions. The concentrations of sixteen elements, including Na, Mg, Al, K, Ca, Mn, Fe, Ni, Cu, Zn, As, Se, Cd, Ba, T1 and Pb were detected using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that Ca, A1, Fe, Mg and Ba on foggy days were 2.0 2.6 times higher than on clear days, and 2.3-2.9 times higher than on hazy days. Concentrations of Cu, Zn, As, Se and Pb on foggy days were 163.5, 1186.7, 65.9, 32.0 and 708.2 ng m-3, respectively, in fine particles, and 68.1, 289.5, 19.8, 1.6 and 103.8 ng m-3, respectively, in coarse particles. This was 1.0~8.4 times higher and 1.4-7.4 times higher than on clear and hazy days, respectively. It is then shown that Mg, A1, Fe, Ca and Ba were mainly associated with coarse particles, peaking at 4.7~5.8 μm; that Cd, Se, Zn, As, T1 and Pb were most dominant in fine particles, peaking at 0.43-1.1 μm; and that Na, K, Ni, Cu and Mn had a multi-mode distribution, with peaks at 0.43-1.1 μm and 4.7-5.8 μm. The enrichment factors indicated that coal combustion along with vehicle and industry emissions may be the main sources of pollution elements.展开更多
Inductively coupled plasma mass spectrometry(ICP-MS) was used to determine the concentration of Pb in atmospheric particulate samples,and the enrichment factor was calculated.The causes of the results were also discus...Inductively coupled plasma mass spectrometry(ICP-MS) was used to determine the concentration of Pb in atmospheric particulate samples,and the enrichment factor was calculated.The causes of the results were also discussed.展开更多
The investigation of pH variation and the chemical composition of rainwater have been studied from April 2003 to October 2006 at a rural area of Nakorn Pathom Province, western Thailand. The pH value ranged from 4.0 t...The investigation of pH variation and the chemical composition of rainwater have been studied from April 2003 to October 2006 at a rural area of Nakorn Pathom Province, western Thailand. The pH value ranged from 4.0 to 7.8 with an average of 6.1. Out of 319 rain events, 72 events were observed in acidic range (pH 〈 5.6). The pH of rainwater gradually increased over the sampling period. The volume-weighted mean concentrations (ixeq]L) of ion species followed the order: Ca^2+ 〉 NH4^+ 〉 SO4^2- 〉 HCO3^- 〉 NO3^- 〉 Na^+ 〉 Cl^- 〉 CH3COO^- 〉 Mg^2+ 〉 K^+ 〉 H^+ 〉 HCOO^- 〉 PO4^3-. Neutralization factor calculations reveal that Ca^2+ plays a major role in neutralization processes in this area. Enrichment factor calculations indicate that SO4^2-, K^+, Ca^2+ and Mg^2+ were originated from non-marine sources. The statistical measure principle component analysis indicates influence of various local emission sources e.g., soil, limestone mines, biomass burning and agricultural emissions, on the chemical composition of rainwater.展开更多
To investigate the environmental quality of the urban surface soil in Yinchuan City, the capital of Ningxia Hui Autonomous Region (Ningxia), China, we sampled surface soil and measured the concentrations of 8 toxic ...To investigate the environmental quality of the urban surface soil in Yinchuan City, the capital of Ningxia Hui Autonomous Region (Ningxia), China, we sampled surface soil and measured the concentrations of 8 toxic metals (Pb, Cr, Cu, Zn, Co, Bi, Ni and V) using X-ray fluorescence spectrometry. The enrichment characteristics and sources of these toxic metals in the soil were analyzed by the enrichment factor (EF) and multivariate statistical analysis. The results showed that the mean concentrations of these toxic metals in the soil samples were 25.0, 109.1, 16.8, 26.0, 37.2, 2.7, 25.3 and 59.9 mg/kg for Pb, Cr, Cu, Zn, Co, Bi, Ni and V, respectively, which were 1.2, 1.8, 0.8, 0.4, 3.2, 8.7, 0.7 and 0.8 times of the corresponding background values of Ningxia soil, respectively. The variations of Pb, Zn, Co, Bi and Ni concentrations in the surface soil of Yinchuan were larger than those of the other metals. Our results also showed that the toxic metals investigated in the soil had different enrichment levels. Both Co and Bi were significantly enriched, whereas Cr was only moderately enriched in the soil. There was a deficiency or minimal enrichment of the other toxic metals in the soil. Source analysis results based on the concentration, enrichment characteristics and multivariate statistical analysis indicated that Cr, V and Ni originated from a combination of fossil fuel combustion, traffic pollution and natural occurrence. Pb, Cu and Zn were predominantly derived from natural and traffic sources, while Co and Bi primarily originated from construction sources.展开更多
To understand pollution level and possible sources of atmospheric fine particulates in rural areas of southern Jiangsu Province of China, samples of PM2.5 were collected and analyzed in Xueyan Town and Taihu Lake Stat...To understand pollution level and possible sources of atmospheric fine particulates in rural areas of southern Jiangsu Province of China, samples of PM2.5 were collected and analyzed in Xueyan Town and Taihu Lake Station over three seasons from July 2002 to January 2003. The mass concentrations of PM2.5 and 14 principal component elements were obtained. The results showed that pollution of PM2.5 was serious and the concentration levels of S, Zn, Pb and As were similar to city. There are different seasonal distribution laws of pollutant elements in PM2.5 between two sampling sites, probably due to contribution of local sources, medium or long distance transportation of fine particulates and complicated meteorological conditions. The enrichment levels of S, Zn, Pb, As, K were high, reflecting the influence of anthropogenic activities. Particularly enrichment level of S was much higher in summer, which was probably related to meteorological condition. The result of principal components analysis showed major sources of PM2.5 included crustal resuspension, coal burning, metal processing industry or waste incineration, vehicular emission, which suggests anthropogenic activities is of important influence on PM2.5 in rural areas of southern Jiangsu Province.展开更多
Ombrotrophic bogs are faithful archive of atmospheric metal deposition, but the potential for fens to reconstruct environmental change is often underestimated. In this study, some new data on the Pb depositional histo...Ombrotrophic bogs are faithful archive of atmospheric metal deposition, but the potential for fens to reconstruct environmental change is often underestimated. In this study, some new data on the Pb depositional history in northeast China were provided using two ^210Pb-dated peat sequences from a poor fen in the Fenghuang Mountain of Heilongjiang province. Anthropogenic, detritic and atmospheric soil sources were discriminated using a two-step sequential digestion (weak acid leaching to liberate mobile Pb which is often regarded as anthropogenic Pb, especially for recent samples) and a ratio of unsupported ^210Pb and supported ^210Pb with the logic of that the ^214Pb mainly represents the residual detritus (constant throughout the core) and the unsupported ^210Pb arises from atmospheric fallout. A higher ^210Pb/^214Pb suggests more contributions from atmospheric deposition to the Pb content in the peat, and a ratio of 10 was defined to indicate the boundary between detrific input and atmospheric deposition. The detritic Pb was estimated to be 10-13 mg·kg^-1, the anthropogenic Pb ranged from 10-80 mg·kg^-1, and the atmospheric soil-derived Pb ranged from 〈 5 mg·kg^-1 to 30 mg·kg^-1. The history of anthropogenic Pb pollution over the last 150 years was reconstructed, and the calculated Pb deposition rate (AR Pb) ranged from 5 to 56 mg·m^-2·yr^-1. Using Ti as a reliable reference, the enrichment factor of Pb (EF Pb) relative to the upper continental crust was calculated. Both AR Pb and EF Pb increased with time, especially after the foundation of the People's Republic of China. This is consistent with increasing industrialization and coal burning in the last 60 years in northeast China. The present record of anthropogenic Pb deposition was consistent with the previous reports and an increasing trend of environmental pollution due to anthropogenic activities, in contrasts to Europe and North America which have experienced a major environmental cleanup. For the first time, this work estimates atmospheric Pb deposition via a minerotrophic peat core in China. This will enhance the use of peat archives for studies of environmental change.展开更多
A set of shale-dominated source rocks series were deposited during the heyday of lake basin development in the Member 7 of Triassic Yanchang Formation,Ordos Basin,and the thickness is about 110 m.Aimed at whether this...A set of shale-dominated source rocks series were deposited during the heyday of lake basin development in the Member 7 of Triassic Yanchang Formation,Ordos Basin,and the thickness is about 110 m.Aimed at whether this layer can form large-scale oil enrichment of industrial value,comprehensive geological research and exploration practice have been carried out for years and obtained the following important geologic findings.Firstly,widely distributed black shale and dark mudstone with an average organic matter abundance of 13.81%and 3.74%,respectively,lay solid material foundation for the formation of shale oil.Secondly,sandy rocks sandwiched in thick organic-rich shale formations constitute an oil-rich"sweet spot",the average thickness of thin sandstone is 3.5 m.Thirdly,fine-grained sandstone and siltstone reservoirs have mainly small pores of 2–8μm and throats of 20–150 nm in radius,but with a large number of micro-pores and nano-throats,through fracturing,the reservoirs can provide good conductivity for the fluid in it.Fourthly,continued high-intensity hydrocarbon generation led to a pressure difference between the source rock and thin-layer reservoir of up to 8–16 MPa during geological history,driven by the high pressure,the oil charged into the reservoirs in large area,with oil saturation reaching more than 70%.Under the guidance of the above theory,in 2019,the Qingcheng Oilfield with geologic oil reserves of billion ton order was proved in the classⅠmulti-stage superimposed sandstone shale reservoir of Chang 7 Member by the Changqing Oilfield Branch through implementation of overall exploration and horizontal well volume fracturing.Two risk exploration horizontal wells were deployed for the classⅡthick layer mud shale interbedded with thin layers of silt-and fine-sandstones reservoir in the Chang 73 submember,and they were tested high yield oil flows of more than 100 tons per day,marking major breakthroughs in petroleum exploration in classⅠshale reservoirs.The new discoveries have expanded the domain of unconventional petroleum exploration.展开更多
[Objective] The aim was to study the concentration characteristics and sources of chemical elements in atmospheric fine particles (PM2.5) in autumn in Xi’an City. [Method] By means of mini-volume sampler, PM2.5 sampl...[Objective] The aim was to study the concentration characteristics and sources of chemical elements in atmospheric fine particles (PM2.5) in autumn in Xi’an City. [Method] By means of mini-volume sampler, PM2.5 samples in atmosphere in Xi’an were collected in October 2009, and the concentration characteristics and sources of elements in PM2.5 were analyzed. [Result] The average mass concentration of PM2.5 in atmosphere in autumn in Xi’an City was 168.44 μg/m3 which was higher than that of Beijing and Pearl River Delta area, and the minimum and maximum value were 53.29 and 358.16 μg/m3, respectively. The mass concentration of S, Zn, K, Cl, Ca and Fe in PM2.5 was above 1.0 μg/m3, being at high pollution level. In addition, K had obvious correlation with organic carbon (OC) and element carbon (EC), with the correlation coefficients of 0.76 and 0.75 (P<0.000 1), respectively, and it showed that OC and EC had the same source as K, namely biomass burning had certain contribution to OC and EC. Enrichment factors analysis revealed that K, Ca, Fe, Ti, Mn and Cr mainly came from earth crust, rock weathering and other natural sources, while anthropogenic pollution sources had great effects on S, Zn, Cl, Pb, Br, Mo, Cd and As which were affected by soil dust and other natural sources slightly, and Cd had the highest enrichment factor and mainly came from metal smelting. In a word, coal combustion, biomass burning, vehicle emissions, metallurgical, chemical industry and dust were the main sources of PM2.5 in autumn in Xi’an. [Conclusion] The study could provide theoretical foundation for the control of urban environmental pollution.展开更多
The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for...The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for this study. The samples were analyzed using the Atomic Absorption Spectrophotometer (AAS). The mean concentrations of Mn (611.37 mg/kg) and Zn (955.86 mg/kg) in the sediments were very high compared to the standard in unpolluted sediments. The enrichment factor (EF) shows that there is an enrichment of Mn at some sites (EF (Mn) > 2). The presence of As, Mn, and Zn is also highlighted by the geo-accumulation index (I-geo) which shows slight pollution in Mn (0 < I-geo (Mn) < 1) on some sites. Moderate pollution for As (1 < I-geo (As) < 2) was determined at the treatment site and high pollution in Zn at some sites in the area (I-geo (Zn) > 3). This study shows that the presence of Zn in the sediments is linked to artisanal gold mining activities. Indeed, Zn is much used for gold recovery. The statistical analysis (PCA) shows, on the one hand, natural mineralization of the sediments and addition of metals linked to anthropic activities corresponding to the erosion of mining discharges. The surface sediments of the Kokumbo mining sites show pollution in As, Mn, and Zn.展开更多
The Orontes river basin can be considered one of the most polluted areas in the eastern Mediterranean due to the intense urban occupation, intensive agriculture irrigation, and large numbers of different industries ac...The Orontes river basin can be considered one of the most polluted areas in the eastern Mediterranean due to the intense urban occupation, intensive agriculture irrigation, and large numbers of different industries activities. The objective of the study was to assess the extent and severity of heavy metal pollution of arable soils of Hama floodplain, in order to provide a general insight vision of pollution status in this intensive agricultural production area. The present and spatial distribution of four heavy metals (Cd, Cu, Pb, Zn) concentration have been examined in 5 monitoring sites of river’s water along the part of the river passing through the plain of Hama;and also from 93 samples of topsoil from the area surrounding the city of Hama have been examined. The concentrations of heavy metals in both river water and soil were within the international standards. Water analyses indicated pH of moderately alkaline, no irrigation problem related to ammonium nitrogen and phosphate phosphorus, while the Electrical Conductivity (EC) has referred to an increasing problem. Geo-accumulation Index (Igeo) refers to strong building up for Cd, Pb, and very strongly for Cu. Soil analyses refer to clayey, calcareous, and alkaline soil with pH ranges from 7.5 to 8.6, with significantly higher organic matter content especially near sewage plants, attributed to irrigation with untreated sewage sludge water. Geostatistical analysis of data showed up normal spatial distribution related to the high variation between the values of the studied elements;whereas the Cu and Cd concentrations were higher than allowable limit near the steel, rubber wheel factories and reach 127 for Cu and 9.8 μg·g-1 for Cd. Additionally, a high concentration of Cu was significantly associated with organic matter content. The concentration of Pb was within the limits, with the exception of riverbanks where the values of Pb exceed 95 μg·g-1, with (Igeo) of 4.22 refers strongly to very strong accumulation. Total Zn concentration showed higher variability and values ranging from 13 to 760 μg·g-1, with a distribution trend increases from southeast to northwest. However, its environmental risk will be more serious to human and livestock.展开更多
Background: Groundwater is an important source of water. Since the control and removal of pollution are expensive, it is essential to identify the possible sources of contamination and to correctly classify groundwate...Background: Groundwater is an important source of water. Since the control and removal of pollution are expensive, it is essential to identify the possible sources of contamination and to correctly classify groundwater on the basis of its intrinsic and integrated vulnerability. Objectives: To group ground water chemical ions and heavy metals parameters into similar groups. Method: The investigation made use of standard analytical procedures. All sampling, conservation, transportation and analysis followed standard procedures described in APHA (2012). To prevent degradation of the organic substances, all obtained samples were transferred to the laboratory, while kept in an icebox. Results: Sampling records from the same area are generally assigned to the same cluster during hierarchical cluster analysis (HCA). The cluster diagram shows the grouping of the heavy metal in the study area during wet and dry seasons. It reveals that 5 distinct clusters were identified for wet season and 4 clusters were identified during dry season. Also, it reveals that 5 distinct clusters were identified for wet season and for dry season, 4 distinct clusters were identified. Conclusion: The findings of this study are significant for policymakers and agencies in terms of dealing with the issues identified to enhance sustainable livelihood practices in the oil rich Niger Delta region of Nigeria. Therefore, decision-makers should take proper initiatives to get local people aware of the endangered zones before use, as drinking water is key to good health. Similarly, multinational oil companies will find it useful in their quest for viable social corporate responsibility and remediation plans in their respective host communities. The method proved to be a useful and objective tool for environmental planning.展开更多
On Peak Namjagbarwa (Tibet Plateau), Lushan Mountain (Province Jiangxi), Flower Mountain and Shangdianzi (Beijing, near Great Wall) aerosol samples have been collected by cascade samplers. For comparison aerosol sampl...On Peak Namjagbarwa (Tibet Plateau), Lushan Mountain (Province Jiangxi), Flower Mountain and Shangdianzi (Beijing, near Great Wall) aerosol samples have been collected by cascade samplers. For comparison aerosol samples from Beijing City, Pacific Ocean and South Pole also have been collected. Samples were analyzed with PIXE or XFA instruments. Factor analysis and enrichment factor calculation were performed to process the data.展开更多
Geochemical investigation of the soils around quarry and barite mine sites in part of Akamkpa and Biase area of Southeastern Nigeria, was carried out to assess the concentration and enrichment levels of some heavy met...Geochemical investigation of the soils around quarry and barite mine sites in part of Akamkpa and Biase area of Southeastern Nigeria, was carried out to assess the concentration and enrichment levels of some heavy metals and trace elements in the soils. The investigation involved the collection of fifteen (15) soil samples between the depth of 15 - 30 cm. The samples were dried at room temperature, prepared and analyzed for heavy metals using inductively couple plasma mass spectrometer. The result shows that the concentration of Co, Cr, Nb, Pb and Sn were higher than the average shale values around the quarries while Ba, Pb and Sn were higher around the barite mines. The contamination factor indicates low to minimal contamination and low to considerable contamination around the quarries and barite mines respectively. While the Enrichment factor indicates minimal to significant enrichment around the quarries and minimal to extremely high enrichments around the barite mines. The result of the factor analysis and spatial distribution of the heavy metals suggests that the metal concentration and enrichment were controlled by the rock types, weathering and anthropogenic activities around the mine sites.展开更多
基金Supported by the National Natural Science Foundation of China(U22B6004)the PetroChina Research Institute of Petroleum Exploration&Development Project(2022yjcq03).
文摘The geological characteristics and production practices of the major middle-and high-maturity shale oil exploration areas in China are analyzed.Combined with laboratory results,it is clear that three essential conditions,i.e.economic initial production,commercial cumulative oil production of single well,and large-scale recoverable reserves confirmed by the testing production,determine whether the continental shale oil can be put into large-scale commercial development.The quantity and quality of movable hydrocarbons are confirmed to be crucial to economic development of shale oil,and focuses in evaluation of shale oil enrichment area/interval.The evaluation indexes of movable hydrocarbon enrichment include:(1)the material basis for forming retained hydrocarbon,including TOC>2%(preferentially 3%-4%),and typeⅠ-Ⅱkerogens;(2)the mobility of retained hydrocarbon,which is closely related to the hydrocarbon composition and flow behaviors of light/heavy components,and can be evaluated from the perspectives of thermal maturity(Ro),gas-oil ratio(GOR),crude oil density,quality of hydrocarbon components,preservation conditions;and(3)the reservoir characteristics associated with the engineering reconstruction,including the main pore throat distribution zone,reservoir physical properties(including fractures),lamellation feature and diagenetic stage,etc.Accordingly,13 evaluation indexes in three categories and their reference values are established.The evaluation indicates that the light shale oil zones in the Gulong Sag of Songliao Basin have the most favorable enrichment conditions of movable hydrocarbons,followed by light oil and black oil zones,containing 20.8×10^(8) t light oil resources in reservoirs with R_(0)>1.2%,pressure coefficient greater than 1.4,effective porosity greater than 6%,crude oil density less than 0.82 g/cm^(3),and GOR>100 m/m^(3).The shale oil in the Gulong Sag can be explored and developed separately by the categories(resource sweet spot,engineering sweet spot,and tight oil sweet spot)depending on shale oil flowability.The Gulong Sag is the most promising area to achieve large-scale breakthrough and production of continental shale oil in China.
文摘Based on the combination of core observation,experimental analysis and testingand geological analysis,the main controlling factors of shale oil enrichment in the Lower Permian Fengcheng Formation in the Mahu Sag of the Junggar Basin are clarified,and a shale oil enrichment model is established.The results show that the enrichment of shale oil in the Fengcheng Formation in the Mahu Sag is controlled by the organic abundance,organic type,reservoir capacity and the amount of migration hydrocarbon in shale.The abundance of organic matter provides the material basis for shale oil enrichment,and the shales containing typesⅠandⅡorganic matters have good oil content.The reservoir capacity controls shale oil enrichment.Macropores are the main space for shale oil enrichment in the Fengcheng Formation,and pore size and fracture scale directly control the degree of shale oil enrichment.The migration of hydrocarbons in shale affects shale oil enrichment.The shale that has expelled hydrocarbons has poor oil content,while the shale that has received hydrocarbons migrated from other strata has good oil content.Lithofacies reflect the hydrocarbon generation and storage capacity comprehensively.The laminated felsic shale,laminated lime-dolomitic shale and thick-layered felsic shale have good oil content,and they are favorable lithofacies for shale oil enrichment.Under the control of these factors,relative migration of hydrocarbons occurred within the Fengcheng shale,which leads to the the difference in the enrichment process of shale oil.Accordingly,the enrichment mode of shale oil in Fengcheng Formation is established as"in-situ enrichment"and"migration enrichment".By superimposing favorable lithofacies and main controlling factors of enrichment,the sweet spot of shale oil in the Fengcheng Formation can be selected which has great significance for the exploration and development of shale oil.
基金National Natural Science Foundation of China(Nos.4180130642171466)The Scientific Research Program of the Department of Natural Resources of Hubei Province(No.ZRZY2021KJ02)。
文摘Effective detection of abnormal electricity users and analysis of the spatial distribution and influencing factors of abnormal electricity consumption in urban areas have positive effects on the quality of electricity consumption by customers,safe operation of power grids,and sustainable development of cities.However,current abnormal electricity consumption detection models do not consider the time dependence of time-series data and rely on a large number of training samples,and no study has analyzed the spatial distribution and influencing factors of abnormal electricity consumption in urban areas.In this study,we use the Seasonal-Trend decomposition procedure based on Loess(STL)based time series decomposition and outlier detection to detect abnormal electricity consumption in the central city of Pingxiang,and analyze the relationship between spatial variation and urban functions through Geodetector.The results show that the degree of abnormal electricity consumption in urban areas is related to geographic location and has spatial heterogeneity,and the abnormal electricity users are mainly located in areas with highly mixed residential,commercial and entertainment functions in the city.The results obtained from this study can provide a reference basis and a theoretical foundation for the detection of abnormal electricity consumption by users and the arming of electricity theft devices in the power grid.
文摘This study is performed to know the contamination level of heavy metals on the surrounding agricultural soils at the site of Barapukuria Coal Mine Company Limited (BCMCL). Total concentrations of eight heavy metals (Cu, As, Cd, Zn, Pb, Cr, Ni and Mn) were measured in that soil. To calculate the contamination level, the enrichment factor (EF), geoaccumulation index (I<sub>geo</sub>) and Hakanson potential ecological risk index were done. I<sub>geo</sub> values indicated that the study areas at all stations were suffering from moderate contamination with As. The results of enrichment factor revealed that soils in all stations were in extremely high enrichment condition by As metal. Under Hakanson potential ecological risk index, the contamination coefficient () and potential ecological risk index () were calculated. The degree of contamination at BCMCL area reflects moderate contamination. By considering the ecological risk index of a particular heavy metal, the order is as follows: Cd > As > Cu > Pb > Ni > Cr > Zn and Cd has the highest risk index and poses the greatest damage to the BCMCL area’s soil. EF, I<sub>geo</sub> values and potential ecological risk index indicate that there is considerable As and Cd pollution, mainly caused by coal mine drainage water.
基金supported by the National Natural Science Foundation of China (No.40673062)
文摘The Fe, Zn, Mn and Pb concentrations in the seawater dissolved phase were investigated in the sea-surface microlayer (SML), subsurface water (SSW) and bottom water (BW) samples collected at of three mariculture areas of the Nanao Island ocean zone. The results showed that the SML and the BW were important compartments for these heavy metals in the mariculture areas and the concentrations varied from 23.0 μg/L to 268.0 μg/L(Fe), 11.0 μg/L to 82.2 μg/L(Zn), 1.5 μg/L to 11.0 μg/L(Mn) and 6.0 μg/L to 40.5 μg/L(Pb) in SSW, while a clear enrichment is observed in the SML, where these ranged from 27.5 μg/L to 286.5 μg/L(Fe), 13.5/lg/L to 89.0μg/L(Zn), 3.0μg/L to 12.0 μg/L(Mn) and 7.0 μg/L to 46.0μg/L(Pb). The enrichment factors were in the range of 1.07 - 1.39 which showed a slight enrichment. The average enrichment factors of Fe, Zn, Pb and Mn were 1.18, 1.13, 1.12 and 1.30, respectively. The average enrichment factors in shellfish, fish and gracilaria lemaneaformis farming areas were 1.26, 1.19 and 1.11, respectively, which showed that the surface activity was highest in the shellfish farming area. Furthermore, the heavy metals concentrations were lowest in the gracUaria lemaneaformis farming area. The results of single factor contamination index showed that the investigated areas were slightly contaminated with Zn, while the partial farming areas were seriously contaminated with Pd during a certain period of time.
基金supported by the Special Scientific Research Funds for Environment Protection Commonweal Section of China (Grant Nos. 201009001)the National Basic Research Program of China (Grant No. 2010CB428503)+4 种基金the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. IAP09320)the National Natural Science Foundation of China (Grant Nos. 41075096 and 40975076)the Research and Development Special Fund for Public Welfare Industry (Meteorology) of the China Meteorological Administration (Grant No. GYHY201006047)the Ministry of Science and Technology of China (Grant No. 2010DFA22770)the Innovation Method Fund of China (Grant No. 2008IM020500)
文摘PM2.5 aerosols were sampled in urban Chengdu from April 2009 to January 2010, and their chemical compositions were characterized in detail for elements, water soluble inorganic ions, and carbonaceous mat- ter. The annual average of PM2.5 was 165 btg m a, which is generally higher than measurements in other Chinese cities, suggesting serious particulate pollution issues in the city. Water soluble ions contributed 43.5% to the annual total PM2.5 mass, carbonaceous aerosols including elemental carbon and organic car- bon contributed 32.0%, and trace elements contributed 13.8~0. Distinct daily and seasonal variations were observed in the mass concentrations of PM2.5 and its components, reflecting the seasonal variations of dif- ferent anthropogenic and natural sources. Weakly acidic to neutral particles were found for PMz5. Major sources of PM2.u identified from source apportionment analysis included coal combustion, traffic exhaust, biomass burning, soil dust, and construction dust emissions. The low nitrate: sulfate ratio suggested that stationary emissions were more important than vehicle emissions. The reconstructed masses of ammonium sulfate, ammonium nitrate, particulate carbonaceous matter, and fine soil accounted for 79% of the total measured PM2.5 mass; they also accounted for 92% of the total measured particle scattering.
文摘In the east coast Peninsular Malaysia region,sediments are transported by several rivers from the east Malaysia into the South China Sea estuary.In the vicinity of the five river estuaries core sediments were collected in order to investigate rare earth elements(REEs) profile.Core sediments were divided into strata of between 2 to 4 cm intervals and prepared for analyzing by ICP-AES.REE concentrations of 54.3 μg/gr at 24–26 cm in EC4 increased to 114.1 μg/gr at 20–22 cm in EC5.The measured concentration of ...
基金supported financially by the National Natural Science Foundation of China(40525016)the National Basic Research Program(2007CB407303 and 2006CB403702)
文摘Total suspended particulates (TSP) samples were collected using low pressure impactors (Andersen Series 20-800, USA) on typical clear, hazy and foggy days in Beijing in order to investigate the characteristics of size distributions and elemental compositions of particulate matter (PM) in different weather conditions. The concentrations of sixteen elements, including Na, Mg, Al, K, Ca, Mn, Fe, Ni, Cu, Zn, As, Se, Cd, Ba, T1 and Pb were detected using inductively coupled plasma mass spectrometry (ICP-MS). The results showed that Ca, A1, Fe, Mg and Ba on foggy days were 2.0 2.6 times higher than on clear days, and 2.3-2.9 times higher than on hazy days. Concentrations of Cu, Zn, As, Se and Pb on foggy days were 163.5, 1186.7, 65.9, 32.0 and 708.2 ng m-3, respectively, in fine particles, and 68.1, 289.5, 19.8, 1.6 and 103.8 ng m-3, respectively, in coarse particles. This was 1.0~8.4 times higher and 1.4-7.4 times higher than on clear and hazy days, respectively. It is then shown that Mg, A1, Fe, Ca and Ba were mainly associated with coarse particles, peaking at 4.7~5.8 μm; that Cd, Se, Zn, As, T1 and Pb were most dominant in fine particles, peaking at 0.43-1.1 μm; and that Na, K, Ni, Cu and Mn had a multi-mode distribution, with peaks at 0.43-1.1 μm and 4.7-5.8 μm. The enrichment factors indicated that coal combustion along with vehicle and industry emissions may be the main sources of pollution elements.
文摘Inductively coupled plasma mass spectrometry(ICP-MS) was used to determine the concentration of Pb in atmospheric particulate samples,and the enrichment factor was calculated.The causes of the results were also discussed.
文摘The investigation of pH variation and the chemical composition of rainwater have been studied from April 2003 to October 2006 at a rural area of Nakorn Pathom Province, western Thailand. The pH value ranged from 4.0 to 7.8 with an average of 6.1. Out of 319 rain events, 72 events were observed in acidic range (pH 〈 5.6). The pH of rainwater gradually increased over the sampling period. The volume-weighted mean concentrations (ixeq]L) of ion species followed the order: Ca^2+ 〉 NH4^+ 〉 SO4^2- 〉 HCO3^- 〉 NO3^- 〉 Na^+ 〉 Cl^- 〉 CH3COO^- 〉 Mg^2+ 〉 K^+ 〉 H^+ 〉 HCOO^- 〉 PO4^3-. Neutralization factor calculations reveal that Ca^2+ plays a major role in neutralization processes in this area. Enrichment factor calculations indicate that SO4^2-, K^+, Ca^2+ and Mg^2+ were originated from non-marine sources. The statistical measure principle component analysis indicates influence of various local emission sources e.g., soil, limestone mines, biomass burning and agricultural emissions, on the chemical composition of rainwater.
基金supported by the National Natural Science Foundation of China (41271510, 41461098)the Fundamental Research Funds for the Central Universities of China (GK201601009, 2017TS027)
文摘To investigate the environmental quality of the urban surface soil in Yinchuan City, the capital of Ningxia Hui Autonomous Region (Ningxia), China, we sampled surface soil and measured the concentrations of 8 toxic metals (Pb, Cr, Cu, Zn, Co, Bi, Ni and V) using X-ray fluorescence spectrometry. The enrichment characteristics and sources of these toxic metals in the soil were analyzed by the enrichment factor (EF) and multivariate statistical analysis. The results showed that the mean concentrations of these toxic metals in the soil samples were 25.0, 109.1, 16.8, 26.0, 37.2, 2.7, 25.3 and 59.9 mg/kg for Pb, Cr, Cu, Zn, Co, Bi, Ni and V, respectively, which were 1.2, 1.8, 0.8, 0.4, 3.2, 8.7, 0.7 and 0.8 times of the corresponding background values of Ningxia soil, respectively. The variations of Pb, Zn, Co, Bi and Ni concentrations in the surface soil of Yinchuan were larger than those of the other metals. Our results also showed that the toxic metals investigated in the soil had different enrichment levels. Both Co and Bi were significantly enriched, whereas Cr was only moderately enriched in the soil. There was a deficiency or minimal enrichment of the other toxic metals in the soil. Source analysis results based on the concentration, enrichment characteristics and multivariate statistical analysis indicated that Cr, V and Ni originated from a combination of fossil fuel combustion, traffic pollution and natural occurrence. Pb, Cu and Zn were predominantly derived from natural and traffic sources, while Co and Bi primarily originated from construction sources.
文摘To understand pollution level and possible sources of atmospheric fine particulates in rural areas of southern Jiangsu Province of China, samples of PM2.5 were collected and analyzed in Xueyan Town and Taihu Lake Station over three seasons from July 2002 to January 2003. The mass concentrations of PM2.5 and 14 principal component elements were obtained. The results showed that pollution of PM2.5 was serious and the concentration levels of S, Zn, Pb and As were similar to city. There are different seasonal distribution laws of pollutant elements in PM2.5 between two sampling sites, probably due to contribution of local sources, medium or long distance transportation of fine particulates and complicated meteorological conditions. The enrichment levels of S, Zn, Pb, As, K were high, reflecting the influence of anthropogenic activities. Particularly enrichment level of S was much higher in summer, which was probably related to meteorological condition. The result of principal components analysis showed major sources of PM2.5 included crustal resuspension, coal burning, metal processing industry or waste incineration, vehicular emission, which suggests anthropogenic activities is of important influence on PM2.5 in rural areas of southern Jiangsu Province.
基金supported by the National Natural Science Foundation of China (Grant No.41301215)the Natural Science Foundation of Jiangsu Province,China (Grant No.BK20131058)+1 种基金the National Basic Research Program of China(Grant No.2012CB956100)the International Atomic Energy Agency (RC-19018)
文摘Ombrotrophic bogs are faithful archive of atmospheric metal deposition, but the potential for fens to reconstruct environmental change is often underestimated. In this study, some new data on the Pb depositional history in northeast China were provided using two ^210Pb-dated peat sequences from a poor fen in the Fenghuang Mountain of Heilongjiang province. Anthropogenic, detritic and atmospheric soil sources were discriminated using a two-step sequential digestion (weak acid leaching to liberate mobile Pb which is often regarded as anthropogenic Pb, especially for recent samples) and a ratio of unsupported ^210Pb and supported ^210Pb with the logic of that the ^214Pb mainly represents the residual detritus (constant throughout the core) and the unsupported ^210Pb arises from atmospheric fallout. A higher ^210Pb/^214Pb suggests more contributions from atmospheric deposition to the Pb content in the peat, and a ratio of 10 was defined to indicate the boundary between detrific input and atmospheric deposition. The detritic Pb was estimated to be 10-13 mg·kg^-1, the anthropogenic Pb ranged from 10-80 mg·kg^-1, and the atmospheric soil-derived Pb ranged from 〈 5 mg·kg^-1 to 30 mg·kg^-1. The history of anthropogenic Pb pollution over the last 150 years was reconstructed, and the calculated Pb deposition rate (AR Pb) ranged from 5 to 56 mg·m^-2·yr^-1. Using Ti as a reliable reference, the enrichment factor of Pb (EF Pb) relative to the upper continental crust was calculated. Both AR Pb and EF Pb increased with time, especially after the foundation of the People's Republic of China. This is consistent with increasing industrialization and coal burning in the last 60 years in northeast China. The present record of anthropogenic Pb deposition was consistent with the previous reports and an increasing trend of environmental pollution due to anthropogenic activities, in contrasts to Europe and North America which have experienced a major environmental cleanup. For the first time, this work estimates atmospheric Pb deposition via a minerotrophic peat core in China. This will enhance the use of peat archives for studies of environmental change.
基金Supported by the China National Science and Technology Major Project(2016ZX05050)the National Key Basic Research and Development Program(973 Program),China(2014CB239003)
文摘A set of shale-dominated source rocks series were deposited during the heyday of lake basin development in the Member 7 of Triassic Yanchang Formation,Ordos Basin,and the thickness is about 110 m.Aimed at whether this layer can form large-scale oil enrichment of industrial value,comprehensive geological research and exploration practice have been carried out for years and obtained the following important geologic findings.Firstly,widely distributed black shale and dark mudstone with an average organic matter abundance of 13.81%and 3.74%,respectively,lay solid material foundation for the formation of shale oil.Secondly,sandy rocks sandwiched in thick organic-rich shale formations constitute an oil-rich"sweet spot",the average thickness of thin sandstone is 3.5 m.Thirdly,fine-grained sandstone and siltstone reservoirs have mainly small pores of 2–8μm and throats of 20–150 nm in radius,but with a large number of micro-pores and nano-throats,through fracturing,the reservoirs can provide good conductivity for the fluid in it.Fourthly,continued high-intensity hydrocarbon generation led to a pressure difference between the source rock and thin-layer reservoir of up to 8–16 MPa during geological history,driven by the high pressure,the oil charged into the reservoirs in large area,with oil saturation reaching more than 70%.Under the guidance of the above theory,in 2019,the Qingcheng Oilfield with geologic oil reserves of billion ton order was proved in the classⅠmulti-stage superimposed sandstone shale reservoir of Chang 7 Member by the Changqing Oilfield Branch through implementation of overall exploration and horizontal well volume fracturing.Two risk exploration horizontal wells were deployed for the classⅡthick layer mud shale interbedded with thin layers of silt-and fine-sandstones reservoir in the Chang 73 submember,and they were tested high yield oil flows of more than 100 tons per day,marking major breakthroughs in petroleum exploration in classⅠshale reservoirs.The new discoveries have expanded the domain of unconventional petroleum exploration.
基金Supported by West Light Joint Scholar Project of Chinese Academy of Sciences
文摘[Objective] The aim was to study the concentration characteristics and sources of chemical elements in atmospheric fine particles (PM2.5) in autumn in Xi’an City. [Method] By means of mini-volume sampler, PM2.5 samples in atmosphere in Xi’an were collected in October 2009, and the concentration characteristics and sources of elements in PM2.5 were analyzed. [Result] The average mass concentration of PM2.5 in atmosphere in autumn in Xi’an City was 168.44 μg/m3 which was higher than that of Beijing and Pearl River Delta area, and the minimum and maximum value were 53.29 and 358.16 μg/m3, respectively. The mass concentration of S, Zn, K, Cl, Ca and Fe in PM2.5 was above 1.0 μg/m3, being at high pollution level. In addition, K had obvious correlation with organic carbon (OC) and element carbon (EC), with the correlation coefficients of 0.76 and 0.75 (P<0.000 1), respectively, and it showed that OC and EC had the same source as K, namely biomass burning had certain contribution to OC and EC. Enrichment factors analysis revealed that K, Ca, Fe, Ti, Mn and Cr mainly came from earth crust, rock weathering and other natural sources, while anthropogenic pollution sources had great effects on S, Zn, Cl, Pb, Br, Mo, Cd and As which were affected by soil dust and other natural sources slightly, and Cd had the highest enrichment factor and mainly came from metal smelting. In a word, coal combustion, biomass burning, vehicle emissions, metallurgical, chemical industry and dust were the main sources of PM2.5 in autumn in Xi’an. [Conclusion] The study could provide theoretical foundation for the control of urban environmental pollution.
文摘The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for this study. The samples were analyzed using the Atomic Absorption Spectrophotometer (AAS). The mean concentrations of Mn (611.37 mg/kg) and Zn (955.86 mg/kg) in the sediments were very high compared to the standard in unpolluted sediments. The enrichment factor (EF) shows that there is an enrichment of Mn at some sites (EF (Mn) > 2). The presence of As, Mn, and Zn is also highlighted by the geo-accumulation index (I-geo) which shows slight pollution in Mn (0 < I-geo (Mn) < 1) on some sites. Moderate pollution for As (1 < I-geo (As) < 2) was determined at the treatment site and high pollution in Zn at some sites in the area (I-geo (Zn) > 3). This study shows that the presence of Zn in the sediments is linked to artisanal gold mining activities. Indeed, Zn is much used for gold recovery. The statistical analysis (PCA) shows, on the one hand, natural mineralization of the sediments and addition of metals linked to anthropic activities corresponding to the erosion of mining discharges. The surface sediments of the Kokumbo mining sites show pollution in As, Mn, and Zn.
文摘The Orontes river basin can be considered one of the most polluted areas in the eastern Mediterranean due to the intense urban occupation, intensive agriculture irrigation, and large numbers of different industries activities. The objective of the study was to assess the extent and severity of heavy metal pollution of arable soils of Hama floodplain, in order to provide a general insight vision of pollution status in this intensive agricultural production area. The present and spatial distribution of four heavy metals (Cd, Cu, Pb, Zn) concentration have been examined in 5 monitoring sites of river’s water along the part of the river passing through the plain of Hama;and also from 93 samples of topsoil from the area surrounding the city of Hama have been examined. The concentrations of heavy metals in both river water and soil were within the international standards. Water analyses indicated pH of moderately alkaline, no irrigation problem related to ammonium nitrogen and phosphate phosphorus, while the Electrical Conductivity (EC) has referred to an increasing problem. Geo-accumulation Index (Igeo) refers to strong building up for Cd, Pb, and very strongly for Cu. Soil analyses refer to clayey, calcareous, and alkaline soil with pH ranges from 7.5 to 8.6, with significantly higher organic matter content especially near sewage plants, attributed to irrigation with untreated sewage sludge water. Geostatistical analysis of data showed up normal spatial distribution related to the high variation between the values of the studied elements;whereas the Cu and Cd concentrations were higher than allowable limit near the steel, rubber wheel factories and reach 127 for Cu and 9.8 μg·g-1 for Cd. Additionally, a high concentration of Cu was significantly associated with organic matter content. The concentration of Pb was within the limits, with the exception of riverbanks where the values of Pb exceed 95 μg·g-1, with (Igeo) of 4.22 refers strongly to very strong accumulation. Total Zn concentration showed higher variability and values ranging from 13 to 760 μg·g-1, with a distribution trend increases from southeast to northwest. However, its environmental risk will be more serious to human and livestock.
文摘Background: Groundwater is an important source of water. Since the control and removal of pollution are expensive, it is essential to identify the possible sources of contamination and to correctly classify groundwater on the basis of its intrinsic and integrated vulnerability. Objectives: To group ground water chemical ions and heavy metals parameters into similar groups. Method: The investigation made use of standard analytical procedures. All sampling, conservation, transportation and analysis followed standard procedures described in APHA (2012). To prevent degradation of the organic substances, all obtained samples were transferred to the laboratory, while kept in an icebox. Results: Sampling records from the same area are generally assigned to the same cluster during hierarchical cluster analysis (HCA). The cluster diagram shows the grouping of the heavy metal in the study area during wet and dry seasons. It reveals that 5 distinct clusters were identified for wet season and 4 clusters were identified during dry season. Also, it reveals that 5 distinct clusters were identified for wet season and for dry season, 4 distinct clusters were identified. Conclusion: The findings of this study are significant for policymakers and agencies in terms of dealing with the issues identified to enhance sustainable livelihood practices in the oil rich Niger Delta region of Nigeria. Therefore, decision-makers should take proper initiatives to get local people aware of the endangered zones before use, as drinking water is key to good health. Similarly, multinational oil companies will find it useful in their quest for viable social corporate responsibility and remediation plans in their respective host communities. The method proved to be a useful and objective tool for environmental planning.
文摘On Peak Namjagbarwa (Tibet Plateau), Lushan Mountain (Province Jiangxi), Flower Mountain and Shangdianzi (Beijing, near Great Wall) aerosol samples have been collected by cascade samplers. For comparison aerosol samples from Beijing City, Pacific Ocean and South Pole also have been collected. Samples were analyzed with PIXE or XFA instruments. Factor analysis and enrichment factor calculation were performed to process the data.
文摘Geochemical investigation of the soils around quarry and barite mine sites in part of Akamkpa and Biase area of Southeastern Nigeria, was carried out to assess the concentration and enrichment levels of some heavy metals and trace elements in the soils. The investigation involved the collection of fifteen (15) soil samples between the depth of 15 - 30 cm. The samples were dried at room temperature, prepared and analyzed for heavy metals using inductively couple plasma mass spectrometer. The result shows that the concentration of Co, Cr, Nb, Pb and Sn were higher than the average shale values around the quarries while Ba, Pb and Sn were higher around the barite mines. The contamination factor indicates low to minimal contamination and low to considerable contamination around the quarries and barite mines respectively. While the Enrichment factor indicates minimal to significant enrichment around the quarries and minimal to extremely high enrichments around the barite mines. The result of the factor analysis and spatial distribution of the heavy metals suggests that the metal concentration and enrichment were controlled by the rock types, weathering and anthropogenic activities around the mine sites.