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
Concentrations of sixteen rare earth elements（REEs） in PM2.5 and potential-source samples, collected in Nanchang city in mid-September 2013, were determined by inductively coupled plasma mass spectrometry（ICP-MS）....Concentrations of sixteen rare earth elements（REEs） in PM2.5 and potential-source samples, collected in Nanchang city in mid-September 2013, were determined by inductively coupled plasma mass spectrometry（ICP-MS）. The results showed that the concentrations of total REEs（ΣREE） ranged from 78.76 to 1351 ng/mg. The order of REEs in PM2.5 samples showed the anthropogenic effects, Ce and Eu were affected more than the other REEs according to the enrichment factors. The results of chondrite-normalized REEs patterns and characteristic parameters showed evident light REEs fractionation, and positive anomalies of Ce and Eu in PM2.5. The other non-local pollution sources affected the PM2.5 samples, according to the triangular diagram of La, Ce and Sm compositions and plot of ΣREE vs δEu. Moreover, plot of（La/Sm）N vs（Gd/Yb）N revealed the effects of local sources. In conclusion, the REEs in potential-source samples were close to the background of local soil, while the REEs in PM2.5 samples in Nanchang city were jointly affected by the investigated local sources and other non-local sources.展开更多
The objective of this study was to investigate the vertical distribution of rare earth elements （REEs） in a natural wetland soil core to understand the influence of natural and anthropogenic activities on geochemica...The objective of this study was to investigate the vertical distribution of rare earth elements （REEs） in a natural wetland soil core to understand the influence of natural and anthropogenic activities on geochemical behavior of REEs. A natural wetland soil core of 95 cm was collected from the Sanjiang Plain in China and sliced into 5 cm slices for analyses of REEs, Fe, Al, Mn, Sc, Y, and soil organic matter （SOM）. Results indicated that SOM was accumulated in the upper part of the soil core （0 to 20 cm depth）, while Fe and Mn was reductively leached from the upper part of the soil core and accumulated in the low part. The content of total REEs ranged from 137.9 to 225.9 mg/kg in the soil core. Content profiles obtained for all REEs were almost identical except for Ce. The highest contents of REEs generally occurred at about 20 cm depth, but enrichment factor （EF） of REEs except Ce was usually the highest in the surface horizon. Average EF ranged from 1.1 for La to 2.1 for Gd. The pronounced shift in EF occurred at about 40 cm depth and it gradually increased from 40 cm depth to surface （except for Ce）, probably suggesting anthropogenic atmospheric deposition of REEs. In comparison with chondrite, Eu was depleted in all horizons, while Ce was negatively anomalous in the top horizons and positively anomalous in the bottom horizons. This positive anomaly of Ce in the bottom horizons was due to its preferential adsorption on Fe and Mn oxides, relative to other REEs. Although both natural and anthropogenic activi-ties influence the geochemical behaviors of REEs in soils, enrichment or mobility of REEs is low in the natural wetland soil core of the San-jiang Plain.展开更多
Selenium is one of the essential trace elements in human body,however,due to the limitation of geographic factors,the intake of selenium is seriously insufficient in most regions.In this study,selenium-enriched peanut...Selenium is one of the essential trace elements in human body,however,due to the limitation of geographic factors,the intake of selenium is seriously insufficient in most regions.In this study,selenium-enriched peanut sprouts with high selenium content were prepared by soaking peanut seeds in sodium selenite.The content and distribution of selenium in germinated peanuts were investigated.The results showed that 200μmol/L sodium selenite and germination for 6 days resulted in the highest total selenium,organic selenium content,and organic selenium conversion in peanut sprouts.Selenium exists in peanut sprouts mainly in organic selenium form,of which selenoproteins are the most critical organic selenium carriers.ABTS free radical scavenging capacity and reducing power assays showed that alkali-soluble protein had the highest antioxidant activity among the four soluble proteins,attributed to its high selenium binding level.Radicle and cotyledons of peanut seedlings were significantly enriched with selenium compared to hypocotyl.Amino acid analysis and SDS-PAGE results showed that selenium increases significantly after peanut germination and selenium enrichment.This study provides a simple,environmentally friendly,and effective way of selenium enrichment and offers a theoretical basis for applying selenium-enriched foods in food and medicine.展开更多
Considering the problems in the discrimination of fracture penetration and the evaluation of fracturing performance in the stimulation of thin sand-mud interbedded reservoirs in the eighth member of Shihezi Formation ...Considering the problems in the discrimination of fracture penetration and the evaluation of fracturing performance in the stimulation of thin sand-mud interbedded reservoirs in the eighth member of Shihezi Formation of Permian(He-8 Member)in the Sulige gas field,a geomechanical model of thin sand-mud interbedded reservoirs considering interlayer heterogeneity was established.The experiment of hydraulic fracture penetration was performed to reveal the mechanism of initiation–extension–interaction–penetration of hydraulic fractures in the thin sand-mud interbedded reservoirs.The unconventional fracture model was used to clarify the vertical initiation and extension characteristics of fractures in thin interbedded reservoirs through numerical simulation.The fracture penetration discrimination criterion and the fracturing performance evaluation method were developed.The results show that the interlayer stress difference is the main geological factor that directly affects the fracture morphology during hydraulic fracturing.When the interlayer stress difference coefficient is less than 0.4 in the Sulige gas field,the fractures can penetrate the barrier and extend in the target sandstone layer.When the interlayer stress difference coefficient is not less than 0.4 and less than 0.45,the factures can penetrate the barrier but cannot extend in the target sandstone layers.When the interlayer stress difference coefficient is greater than 0.45,the fractures only extend in the perforated reservoir,but not penetrate the layers.Increasing the viscosity and pump rates of the fracturing fluid can compensate for the energy loss and break through the barrier limit.The injection of high viscosity(50–100 mPa·s)fracturing fluid at high pump rates(12–18 m^(3)/min)is conducive to fracture penetration in the thin sand-mud interbedded reservoirs in the Sulige gas field.展开更多
In areas with a high geological background of heavy metals,some edible plants could pose a serious threat to human health.In order to find effective methods to remove heavy metals or reduce their harm,this study inves...In areas with a high geological background of heavy metals,some edible plants could pose a serious threat to human health.In order to find effective methods to remove heavy metals or reduce their harm,this study investigated the enrichment conditions of five soil heavy metals,Cd,Pb,Cu,Zn and Cr,in four edible plants in a mining area,Baoshantao,in eastern China that has a high geological background of metals,and two groups of experiments were designed to investigate the effects of passivators on their enrichment.The results showed that the soil heavy metal content in the study area has a certain degree of spatial variability.The five heavy metal element contaminants in the soil are in the order of Cd>Cu>Zn>Pb>Cr.The enrichment coefficients and the transfer coefficients of different edible plants were different for the different heavy metals.The two groups of passivators showed better passivating effects with an increase in passivating agent dosage.The smaller the enrichment coefficient of water spinach,the lower the bioavailability.The results of this study can provide a scientific basis for the restoration of soil heavy metal pollution and the safe use of land in areas with a high geological background of heavy metals.展开更多
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.
基金Project supported by the National Natural Science Foundation of China(21477042,21377042)the Natural Science Foundation of Fujian Province(2016J01065)
文摘Concentrations of sixteen rare earth elements（REEs） in PM2.5 and potential-source samples, collected in Nanchang city in mid-September 2013, were determined by inductively coupled plasma mass spectrometry（ICP-MS）. The results showed that the concentrations of total REEs（ΣREE） ranged from 78.76 to 1351 ng/mg. The order of REEs in PM2.5 samples showed the anthropogenic effects, Ce and Eu were affected more than the other REEs according to the enrichment factors. The results of chondrite-normalized REEs patterns and characteristic parameters showed evident light REEs fractionation, and positive anomalies of Ce and Eu in PM2.5. The other non-local pollution sources affected the PM2.5 samples, according to the triangular diagram of La, Ce and Sm compositions and plot of ΣREE vs δEu. Moreover, plot of（La/Sm）N vs（Gd/Yb）N revealed the effects of local sources. In conclusion, the REEs in potential-source samples were close to the background of local soil, while the REEs in PM2.5 samples in Nanchang city were jointly affected by the investigated local sources and other non-local sources.
基金Project supported by National Natural Science Foundation of China (40930740)
文摘The objective of this study was to investigate the vertical distribution of rare earth elements （REEs） in a natural wetland soil core to understand the influence of natural and anthropogenic activities on geochemical behavior of REEs. A natural wetland soil core of 95 cm was collected from the Sanjiang Plain in China and sliced into 5 cm slices for analyses of REEs, Fe, Al, Mn, Sc, Y, and soil organic matter （SOM）. Results indicated that SOM was accumulated in the upper part of the soil core （0 to 20 cm depth）, while Fe and Mn was reductively leached from the upper part of the soil core and accumulated in the low part. The content of total REEs ranged from 137.9 to 225.9 mg/kg in the soil core. Content profiles obtained for all REEs were almost identical except for Ce. The highest contents of REEs generally occurred at about 20 cm depth, but enrichment factor （EF） of REEs except Ce was usually the highest in the surface horizon. Average EF ranged from 1.1 for La to 2.1 for Gd. The pronounced shift in EF occurred at about 40 cm depth and it gradually increased from 40 cm depth to surface （except for Ce）, probably suggesting anthropogenic atmospheric deposition of REEs. In comparison with chondrite, Eu was depleted in all horizons, while Ce was negatively anomalous in the top horizons and positively anomalous in the bottom horizons. This positive anomaly of Ce in the bottom horizons was due to its preferential adsorption on Fe and Mn oxides, relative to other REEs. Although both natural and anthropogenic activi-ties influence the geochemical behaviors of REEs in soils, enrichment or mobility of REEs is low in the natural wetland soil core of the San-jiang Plain.
基金supported by the National Natural Science Foundation of China[32172259]Key Research and Development Project of Henan Province[231111111800]+1 种基金Innovative Funds Plan of Henan University of Technology [2021ZKCJ03]The Program for the Top Young Talents of Henan Associate for Science and Technology.
文摘Selenium is one of the essential trace elements in human body,however,due to the limitation of geographic factors,the intake of selenium is seriously insufficient in most regions.In this study,selenium-enriched peanut sprouts with high selenium content were prepared by soaking peanut seeds in sodium selenite.The content and distribution of selenium in germinated peanuts were investigated.The results showed that 200μmol/L sodium selenite and germination for 6 days resulted in the highest total selenium,organic selenium content,and organic selenium conversion in peanut sprouts.Selenium exists in peanut sprouts mainly in organic selenium form,of which selenoproteins are the most critical organic selenium carriers.ABTS free radical scavenging capacity and reducing power assays showed that alkali-soluble protein had the highest antioxidant activity among the four soluble proteins,attributed to its high selenium binding level.Radicle and cotyledons of peanut seedlings were significantly enriched with selenium compared to hypocotyl.Amino acid analysis and SDS-PAGE results showed that selenium increases significantly after peanut germination and selenium enrichment.This study provides a simple,environmentally friendly,and effective way of selenium enrichment and offers a theoretical basis for applying selenium-enriched foods in food and medicine.
基金Supported by the National Key Research and Development Program of China(2022YFE0129800)CNPC and China University of Petroleum(Beijing)Strategic Cooperation Science and Technology Special Project(ZLZX2020-02)。
文摘Considering the problems in the discrimination of fracture penetration and the evaluation of fracturing performance in the stimulation of thin sand-mud interbedded reservoirs in the eighth member of Shihezi Formation of Permian(He-8 Member)in the Sulige gas field,a geomechanical model of thin sand-mud interbedded reservoirs considering interlayer heterogeneity was established.The experiment of hydraulic fracture penetration was performed to reveal the mechanism of initiation–extension–interaction–penetration of hydraulic fractures in the thin sand-mud interbedded reservoirs.The unconventional fracture model was used to clarify the vertical initiation and extension characteristics of fractures in thin interbedded reservoirs through numerical simulation.The fracture penetration discrimination criterion and the fracturing performance evaluation method were developed.The results show that the interlayer stress difference is the main geological factor that directly affects the fracture morphology during hydraulic fracturing.When the interlayer stress difference coefficient is less than 0.4 in the Sulige gas field,the fractures can penetrate the barrier and extend in the target sandstone layer.When the interlayer stress difference coefficient is not less than 0.4 and less than 0.45,the factures can penetrate the barrier but cannot extend in the target sandstone layers.When the interlayer stress difference coefficient is greater than 0.45,the fractures only extend in the perforated reservoir,but not penetrate the layers.Increasing the viscosity and pump rates of the fracturing fluid can compensate for the energy loss and break through the barrier limit.The injection of high viscosity(50–100 mPa·s)fracturing fluid at high pump rates(12–18 m^(3)/min)is conducive to fracture penetration in the thin sand-mud interbedded reservoirs in the Sulige gas field.
基金The National Natural Science Foundation of China(42371185)The Anhui Normal University College Students Innovation and EntrepreneurshipTraining Program(2022056511).
文摘In areas with a high geological background of heavy metals,some edible plants could pose a serious threat to human health.In order to find effective methods to remove heavy metals or reduce their harm,this study investigated the enrichment conditions of five soil heavy metals,Cd,Pb,Cu,Zn and Cr,in four edible plants in a mining area,Baoshantao,in eastern China that has a high geological background of metals,and two groups of experiments were designed to investigate the effects of passivators on their enrichment.The results showed that the soil heavy metal content in the study area has a certain degree of spatial variability.The five heavy metal element contaminants in the soil are in the order of Cd>Cu>Zn>Pb>Cr.The enrichment coefficients and the transfer coefficients of different edible plants were different for the different heavy metals.The two groups of passivators showed better passivating effects with an increase in passivating agent dosage.The smaller the enrichment coefficient of water spinach,the lower the bioavailability.The results of this study can provide a scientific basis for the restoration of soil heavy metal pollution and the safe use of land in areas with a high geological background of heavy metals.
