This thesis focuses Arsenic(As) distribution and occurrence in groundwater of Yangtze River Delta economic region, East China. 2019 groundwater samples were collected to analyze 26 chemical compositions, including As....This thesis focuses Arsenic(As) distribution and occurrence in groundwater of Yangtze River Delta economic region, East China. 2019 groundwater samples were collected to analyze 26 chemical compositions, including As. The Principal Component Analysis(PCA) was used to find out As source in groundwater. The results show that average As concentration in groundwater of this study is 9.33 μg/l, and maximum As concentration is up to 510 μg/l. The variation coefficient is 314.34%. High arsenic phreatic water(>10 μg/l) distributes along the Yangtze River and its estuary. Weak hydrodynamic conditions, wide p H value variation range and deteriorating environment are dominating factors, especially in Yangtze River Delta. The PCA suggests that arsenic in phreatic water is mainly of natural origin. Part of arsenic may directly originate from sediment organics and be related to organics decomposition.展开更多
The relevance of groundwater hydrogeochemistry to explain the occurrence and distribution of arsenic in groundwater is of great interest.The insightful discussions on the control of shallow groundwater(<50 m)hydrog...The relevance of groundwater hydrogeochemistry to explain the occurrence and distribution of arsenic in groundwater is of great interest.The insightful discussions on the control of shallow groundwater(<50 m)hydrogeochemistry in arsenic mobilization are known to be a viable tool to explain the arsenic menace in shallow groundwater.The present investigation emphasizes the hydrogeochemical driver and/or control over the reductive dissolution of Fe-bearing host minerals and thereby releasing arsenic into the shallow groundwater of the study area.The study suggests that hydrogeochemical evolution is mainly governed by carbonate minerals dissolution,silicate weathering,and competitive ion-exchange processes in the shallow aquifers(<50 m).The present study also indicates the prevalence of carbonate minerals dissolution over silicate weathering.The emergence of Cl^(-)concentration in the shallow groundwater founds the possibilities of anthropogenic inputs into the shallow aquifers(<50 m).The reducing environment in shallow aquifers(<50 m)of the study area is evident in the reductive dissolution of Febearing shallow aquifer minerals which absorb arsenic in the solid phase and mobilize arsenic onto shallow groundwater.The study opted for many statistical approaches to delineate the correlation among major and minor ionic constituents of the groundwater which are very helpful to understand the comprehensive mechanism of arsenic mobilization into shallow groundwater.展开更多
Groundwater with high arsenic(As) content seriously threatens human life and health. Drinking high-As groundwater for a long time will lead to various pathological changes such as skin cancer, liver cancer,and kidney ...Groundwater with high arsenic(As) content seriously threatens human life and health. Drinking high-As groundwater for a long time will lead to various pathological changes such as skin cancer, liver cancer,and kidney cancer. High-As groundwater has become one of the most serious environmental geological problems in China and even internationally. This paper aims to systematically summarize the sources,migration, distribution, toxicological effects, and treatment techniques of As in natural groundwater in China based on a large number of literature surveys. High-As groundwater in China is mainly distributed in the inland basins in arid and semi-arid environments and the alluvial and lacustrine aquifers in river deltas in humid environments, which are in neutral to weakly alkaline and strongly reducing environments.The content of As in groundwater varies widely, and As(Ⅲ) is the main form. The main mechanism of the formation of high-As groundwater in China is the reduced dissolution of Fe and Mn oxides under the action of organic matter and primary microorganisms, alkaline environment, intense evaporation and concentration, long-term water-rock interaction, and slow groundwater velocity, which promote the continuous migration and enrichment of As in groundwater. There are obvious differences in the toxicity of different forms of As. The toxic of As(Ⅲ) is far more than As(V), which is considered to be more toxic than methyl arsenate(MMA) and dimethyl arsenate(DMA). Inorganic As entering the body is metabolized through a combination of methylation(detoxification) and reduction(activation) and catalyzed by a series of methyltransferases and reductases. At present, remediation methods for high-As groundwater mainly include ion exchange technology, membrane filtration technology, biological treatment technology, nanocomposite adsorption technology, electrochemical technology, and so on. All the above remediation methods still have certain limitations, and it is urgent to develop treatment materials and technical means with stronger As removal performance and sustainability. With the joint efforts of scientists and governments of various countries in the future, this worldwide problem of drinking-water As poisoning will be solved as soon as possible. This paper systematically summarizes and discusses the hot research results of natural high-As groundwater, which could provide a reference for the related research of high-As groundwater in China and even the world.展开更多
Sixteen samples of surface and groundwater from the most southern part of the Hanoi city (Vietnam) has been taken and analyzed for the soluble major ions, namely Na+, K+, , Ca2+, Mg2+, Cl-, , and arsenic as well as mo...Sixteen samples of surface and groundwater from the most southern part of the Hanoi city (Vietnam) has been taken and analyzed for the soluble major ions, namely Na+, K+, , Ca2+, Mg2+, Cl-, , and arsenic as well as molybdenum content along with isotopic composition of deuterium and oxygen (δ2H and δ18O), tritium activity, and δ13C in DIC. The stable isotopic composition of groundwater indicates the water in that area is recharged from the local meteoric and theRed River’s water sources. The mean residence time of the groundwater should be before 60-ies of the past century as its 3H activity ranged from LOD of the analytical technique (0.4 TU) to 2.1 TU only implying that As would not be related to its recent application. The concentrations of As in the water samples is weakly correlated with those of Fe2+ (R2 = 0.08) but it strongly did with the concentrations of bicarbonate (R2 = 0.80). Thus, bicarbonate seems to liberate As adsorbed on hydrous ferric oxides (Hfo) into water through the displacement mechanism. The surface adsorption-desorption of As could be proven by a strong correlation between As and Mo concentrations (R2 = 0.77). The bicarbonate formation in groundwater was thought to be, partly, due to the bio-mineralization of natural organic matter (NOM) by bacteria followed by the dissolution of calcite and/or dolomite present in the sediments. Evidence for the NOM bio-mineralization was found in the close relationship between δ13C and the concentration of bicarbonate in water. Therefore, the mobilization of As in groundwater of bicarbonate type in the southern part of Hanoi city seems to be not only due to the reductive dissolution of the Hfo but the bicarbonate displacement also should be considered.展开更多
The arsenic(As)release from sediments in great lakes is affected by various factors.In this study,the characteristics of As release fromsediments was investigated,and the As sources and sinks with the strengths in sed...The arsenic(As)release from sediments in great lakes is affected by various factors.In this study,the characteristics of As release fromsediments was investigated,and the As sources and sinks with the strengths in sediments from different areas(grass-type,algae-type,and grass-algae alternation areas)in great shallow lakes(Taihu Lake,China)were analyzed,and the influence of P competition in the process of As release was also studied.The results showed that changing trend of the values of equilibrium As concentration in sediments were consistent with the regional changes(0 to 28.12μg/L),and the sediments from algaetype areas had the higher values.The sediments from western lake and northwest lake bay were a strong As and a weak P source,and the north lake bay had the opposite trend of these two regions.Intense P source competition with As from the sediments occurred in algae-type areas.The grass-type areas had strong As and P retention capacities,indicating a sink role of sediment with high As and P sorption capacities.The degree of As and P saturation had similar trend in sediments,and the grass-type areas had the higher values,18.3%-21.4%and 15.31%-20.34%,respectively.Contribution analysis results showed that most of As release contribution was from the bottom(30-50 cm)sediments,and the surface(0-10 cm)sediments from algae-type areas contributed more to the overlying water than other region.展开更多
The problem of arsenic(As)poisoning in the upper deltaic plains of the Ganges-Bhagirathi river system of West Bengal(WB),India,is terrifying. Elevated As(】50 ppb)in well water was observed within a depth range of 10-...The problem of arsenic(As)poisoning in the upper deltaic plains of the Ganges-Bhagirathi river system of West Bengal(WB),India,is terrifying. Elevated As(】50 ppb)in well water was observed within a depth range of 10-30 m in older grey terraces of abandoned fluvial channel deposits in the Murshidabad and Malda districts in WB.Both surface and cored(2-20 m)sediment samples from banks of the river Ganges and along a north-south transect of the main tributary Bhagirathi-Hooghly river展开更多
A simple negative ion mobility spectrometer （IMS） is designed and used to investi- gate the factors that influence the number and efficiency of electrons generated by the needle-ring pulsed corona discharge electron...A simple negative ion mobility spectrometer （IMS） is designed and used to investi- gate the factors that influence the number and efficiency of electrons generated by the needle-ring pulsed corona discharge electron source. Simulation with Ansoft Maxwell 12 is carried out to analyze the electric field distribution within the IMS, and to offer the basis and foundation for analyzing the measurement results. The measurement results of the quantities of electrons show that when the drift electric field strength and the ring inner diameter rise, both the number of ef- fective electrons and the effective electron rate are increased. When the discharge voltage becomes stronger, the number of effective electrons goes up while the effective electron rate goes down. In light of the simulation results, mechanisms underlying the effects of drift electric field strength, ring inner diameter, and discharge voltage on the effective electron number and effective electron rate are discussed. These will make great sense for designing negative ion mode IMS using the needle-ring pulsed corona discharge as the electron source.展开更多
Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Seco...Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Secondary precipitates that form from the dissolution of the primary sulfides exert a greater influence on arsenic mobility in the geothermal environment. Fe-hydroxides have very good affinity with dissolved arsenate and are stable under most surface oxidizing conditions. Both amorphous silica directly precipitated from geothermal fluids and possibly a kaolinite alteration can host a small significant amount of arsenic. These silicates are also more stable under a wide range ofpH and redox conditions.展开更多
We propose an on-demand multipath routing algorithm in a mobile ad hoc network for video transmission and evaluate its real world performance in video streaming application. There have been a number of multipath routi...We propose an on-demand multipath routing algorithm in a mobile ad hoc network for video transmission and evaluate its real world performance in video streaming application. There have been a number of multipath routing protocols extended from AODV which is a well-known single path routing protocol. Multipath routing protocols indicate good performance in the reduction of route discovery latency and unnecessary routing packets in simulations. We show that the route establishment using source route lists provided by us (Hu and Johnson, 2002) can reduce the route discovery latency, select stable routes automatically, and work well for live video streaming without limitation of the hop count based approaches. We evaluate this proposed method compared with the original AODV by using eight laptop PCs and demonstrate live streaming experiments.展开更多
In an integrated energy system(IES) composed of multiple subsystems, energy coupling causes an energy supply blockage or shutdown in one subsystem, thereby affecting the energy flow distribution optimization of other ...In an integrated energy system(IES) composed of multiple subsystems, energy coupling causes an energy supply blockage or shutdown in one subsystem, thereby affecting the energy flow distribution optimization of other subsystems.The energy supply should be globally optimized during the IES energy supply restoration process to produce the highest restoration net income. Mobile emergency sources can be quickly and flexibly connected to supply energy after an energy outage to ensure a reliable supply to the system, which adds complexity to the decision. This study focuses on a powergas IES with mobile emergency sources and analyzes the coupling relationship between the gas distribution system and the power distribution system in terms of sources, networks, and loads, and the influence of mobile emergency source transportation. The influence of the transient process caused by the restoration operation of the gas distribution system on the power distribution system is also discussed. An optimization model for power-gas IES restoration was established with the objective of maximizing the net income. The coordinated restoration optimization decision-making process was also built to realize the decoupling iteration of the power-gas IES, including system status recognition, mobile emergency source dispatching optimization, gas-to-power gas flow optimization, and parallel intra-partition restoration scheme optimization for both the power and gas distribution systems. A simulation test power-gas IES consisting of an 81-node medium-voltage power distribution network, an 89-node medium-pressure gas distribution network, and four mobile emergency sources was constructed. The simulation analysis verified the efficiency of the proposed coordinated restoration optimization method.展开更多
With the increasing severity of arsenic(As)pollution,quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the pr...With the increasing severity of arsenic(As)pollution,quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the precise control strategies.Taking the industrialintensive Jinsha River Basin as typical area,a two-dimensional hydrodynamic water quality model coupled with Soil andWater Assessment Tool(SWAT)model was developed to accurately simulate the watershed-scale distribution and transport of As in the terrestrial and aquatic environment at high spatial and temporal resolution.The effects of hydro-climate change,hydropower station construction and non-point source emissions on Aswere quantified based on the coupled model.The result indicated that higher As concentration areas mainly centralized in urban districts and concentration slowly decreased from upstream to downstream.Due to the enhanced rainfall,the As concentration was significantly higher during the rainy season than the dry season.Hydro-climate change and the construction of hydropower station not only affected the dissolved As concentration,but also affected the adsorption and desorption of As in sediment.Furthermore,As concentration increased with the input of non-point source pollution,with the maximum increase about 30%,resulting that non-point sources contributed important pollutant impacts to waterways.The coupled model used in pollutant behavior analysis is generalwith high potential application to predict and mitigate water pollution.展开更多
The goal of this study is to analyze the relative contribution of different emission source categories to ozone in the Houston-Galveston-Brazoria (HGB) area of Texas. Emission Processing System (EPS3) is used to prepa...The goal of this study is to analyze the relative contribution of different emission source categories to ozone in the Houston-Galveston-Brazoria (HGB) area of Texas. Emission Processing System (EPS3) is used to prepare the emission files for five different source combination cases (Base case, Biogenic, Area + Biogenic, Mobile + Biogenic, Low-level Point + Biogenic). These emission files are used to perform photochemical modeling with Comprehensive Air Quality Model with Extensions (CAMx), and the results are analyzed with Visual Environment for Rich Data Interpretation (VERDI) tool. The daily maximum ozone concentrations and individual contributions of the source categories were analyzed over a 15-day study period between June 1-15, 2012, at three locations (University of Houston-Sugarland, Bayland Park and Conroe). Biogenic sources contributed an average of 49.7% ± 12.8%, 43.1% ± 12.0%, and 39.9% ± 9.28% at Sugarland, Bayland Park and Conroe sites respectively, indicating the significance of isoprene emissions from the vegetation in northeast Houston. On peak ozone days, contribution of Mobile + Biogenic source category averages about 80.1% ± 12.6%, 79.9% ± 6.50%, and 75.9% ± 10.9% at Sugarland, Bayland Park and Conroe sites respectively, indicating the dominance of mobile source NOX emissions and the necessity for regulatory focus on mobile source emissions control.展开更多
There exists a lack of detailed empirical studies to assess the relevance of WebMapping applications. Despite this fact, it is quite common to note that importance and influence of WebMapping applications have increas...There exists a lack of detailed empirical studies to assess the relevance of WebMapping applications. Despite this fact, it is quite common to note that importance and influence of WebMapping applications have increased over the last years. This paper presents the result of an empirical study to analyze the importance of a Desktop-WebMapping application for a gastronomic web 2.0 portal for the city of Osnabrück. An exploratory focus is to evaluate how often geospatial information (in a broader information context) from this web portal is used and how important the WebMapping applications are for the users of the web portal. Furthermore, it is evaluated which WebMapping functions (e.g. routing, queries, printing) are of relevance to the users and what the order of importance is for the provided functions. To-date, just a few mobile WebMapping applications for handheld devices exist. Consequently, for OsnaGo we developed a mobile WebMapping component that can be used with mobile phones, PDAs and other handheld devices to access the web portal (http://www.osnago-mobil.de). Development and user based evaluation is presented in this paper.展开更多
During a routine inspection in a petroleum product terminal, hydrocarbon staining was found in soil along the perimeter of a diesel fuel tank. As the observation was made a few days after a magnitude 5.1 earthquake in...During a routine inspection in a petroleum product terminal, hydrocarbon staining was found in soil along the perimeter of a diesel fuel tank. As the observation was made a few days after a magnitude 5.1 earthquake in the general area of the terminal, the hydrocarbon staining in the soil was suspected to be a result of a leak from the tank. The observation triggered an immediate tank inspection, which included examination of tank exterior, piping and connections;pressure testing;wall thickness gauging;and an inventory check. Results of the initial inspection suggested that there were no integrity issues with the tank. Before more vigorous and more disruptive inspections were conducted, chemical fingerprinting was conducted to assess the nature of soil staining and potential connection with the “suspected” tank leak. Samples were collected from the site, including a diesel fuel sample from the tank, a light non-aqueous phase liquid (LNAPL) sample from the monitoring well in the immediate vicinity, and representative soil samples from the perimeter of, and beneath, the tank. A tiered laboratory analytical approach was taken, which included initial gas chromatography-flame ionization detector carbon chain analysis and final gas chromatography-mass spectrometry or detailed fingerprint analyses. Based on the results of initial inspection, knowledge of LNAPL mobility in response to earthquake seismic waves, and chemical fingerprints of representative samples, it was determined that the soil staining was not a result of suspected tank release but remobilization of hydrocarbons from the historically impacted soil beneath the tank to the soil along the perimeter of the tank.展开更多
Arsenic(As),fluoride(F^(−))are both ubiquitous in groundwater,and co-exposure to these elements through contaminated drinking water may cause detrimental effects on human health more in comparison with individual expo...Arsenic(As),fluoride(F^(−))are both ubiquitous in groundwater,and co-exposure to these elements through contaminated drinking water may cause detrimental effects on human health more in comparison with individual exposure.As,F^(−)co-occurrence in groundwater of the inland plain in Huaihe River Basin,China is a major concern,where inhabitants are rely on groundwater as the leading water source for drinking to date.This work employs an approach of hydrochemical analysis and modelling to identify the possible origin of As and F^(−),to analyze co-enrichment mechanism,and to estimate the associated exposure risk.The results shows presence of elevated As and F^(−)concentrations is an important factor affecting groundwater quality from 62 groundwater samples.The recorded As concentrations vary from 0.23 to 20.40μg/L,with a mean of 5.95μg/L,F^(−)concentrations vary from 0.54 to 2.60μg/L,with a mean of 1.29 mg/L,and 8%of samples are simultaneously above their permissible limits in drinking water by the WHO.Groundwater with As,F^(−)co-contamination is occurred within reducing and alkaline aquifers,and its chemical type is HCO_(3)–Na.The hydrochemical processes involved in the co-contamination are reductive desorption,evaporation,and ion exchange,which are controlled by local geology,geomorphology,and hydrochemistry.Groundwater As is derived and released by reductive desorption and F^(−)is mainly originated by fluorite dissolution.Groundwater As,F^(−)are geogenic sources,and the mechanisms for co-contamination are associated with high elemental abundance,flat terrain,alkaline and reductive groundwater conditions.The research provides a case study about groundwater As,F^(−)co-contamination,which may be enhance understanding the co-enrichment mechanism in semi-humid areas.展开更多
The paper investigated a new method of analyzing perfume odors.The study adopted IMS with glow dischargeas ion source and with positive ion mode.We got the quality characteristics of perfume odors in this way without ...The paper investigated a new method of analyzing perfume odors.The study adopted IMS with glow dischargeas ion source and with positive ion mode.We got the quality characteristics of perfume odors in this way without any collection and concentration process.The quality of perfume odors can be identified by IMS peak characteristics,and the characteristics of different quality of perfume also can be identified.In summary,the IMS is an effective technique in the perfume odor detection,it is also a new way of gas sample analysis.展开更多
A number of natural experiments have recently found that COVID-19 restrictions imposed in nations worldwide are correlated with short-term reductions—in some cases dramatic reductions—in mobile-source air pollutants...A number of natural experiments have recently found that COVID-19 restrictions imposed in nations worldwide are correlated with short-term reductions—in some cases dramatic reductions—in mobile-source air pollutants. Noticeably absent from these studies are estimates of the social net benefits associated with the changes in human behavior underlying the pandemic-induced effects. Using readily available data provided by the state of Utah and the U.S. Environmental Protection Agency’s Co-Benefits Risk Assessment Health Impacts Screening and Mapping Tool (COBRA), we find that daily social net benefit was positive during a pandemic-induced shutdown from March to April, 2020 in Utah’s Wasatch Front region solely when COBRA’s “high” health benefit estimate from combined reductions in PM<sub>2.5</sub> and NO<sub>x</sub> concentrations are weighed against the region’s “low” vehicle-trip cost estimate. All other scenarios correspond with negative net benefit estimates, <i>i.e.</i>, when high and low benefit estimates of reductions solely in PM<sub>2.5</sub> concentrations as well as for combined reductions in PM<sub>2.5</sub> and NO<sub>x</sub> concentrations are weighed against the region’s high vehicle-trip cost estimate. Generally speaking, social net benefits are higher for two of the Wasatch Front’s four counties.展开更多
Antibiotic resistance genes(ARGs)might have great effect on ecological security and human health.Oceans are important reservoirs that receive tremendous amounts of pollutants globally.However,information on the prolif...Antibiotic resistance genes(ARGs)might have great effect on ecological security and human health.Oceans are important reservoirs that receive tremendous amounts of pollutants globally.However,information on the proliferation of ARGs in seawater is still limited.This study performed field sampling to investigate the occurrence and distribution of ARGs in seawater of the South China Sea,which is the deepest and largest sea in China.The results showed that the total absolute abundances of ARGs in seawater samples ranged from 2.1×10^(3)to 2.3×10^(4)copies/mL,with an of 5.0×10^(3)copies/mL and a range of 2.2×10^(3)–1.8×10^(4)copies/mL for those with mobile genetic elements(MGEs).Genes resistant to multidrug,aminoglycoside,tetracycline,and fluoroquinolone antibiotics accounted for 77.3%–88.6%of total ARGs in seawater.Proteobacteria and Cyanobacteria represented 32.1%–56.2%and 30.4%–49.5%of microbial community,respectively.Prochlorococcus_MIT9313 and Clade_la were the prevalent genera in seawater of the South China Sea.Complex co-occurrence relationship existed among ARGs,MGEs,and bacteria.Anthropogenic activities had critical influence on ARGs and MGEs.Hospital wastewater,wastewater treatment plant effluent,sewage,aquaculture tailwater,and runoff were determined as the important sources of ARGs in seawater of the South China Sea based on positive matrix factorization analysis.展开更多
This research investigates the arsenic concentrations in 96 soil samples from a regency in Indonesia using a statistical approach.Soil samples were collected from three depth layers(topsoil[10e20 cm],subsoil[50e60 cm]...This research investigates the arsenic concentrations in 96 soil samples from a regency in Indonesia using a statistical approach.Soil samples were collected from three depth layers(topsoil[10e20 cm],subsoil[50e60 cm],and deep soil[90e100 cm]),with each layer consisting of 32 samples.Statistical analysis using SPSS was employed to analyze potential arsenic sources based on the proximity of study locations to geothermal system areas,land use,distance from industry,and the presence of study locations on fault lines.The findings indicate that the potential source of arsenic contamination in the soil are suspected to be associated with geothermal system activities and the presence of soil samples on fault lines.The arsenic concentration in locations near to the geothermal system(5-10 km)was 45 times higher(OR=45,95%CI=45e362.57,p<0.01).Arsenic was found to be 3.828 times higher in study areas situated on fault zones(OR=3.828,95%CI=1.507e9.719,p<0.01).Additionally,the research suggests that arsenic in the soil may also originate from anthropogenic activities,such as agriculture and industry,as the highest concentrations were found in subsoil or topsoil layers compared to deep soil.The variation in arsenic concentration from highest to lowest in agricultural soil layers was subsoil>topsoil>deep soil,whereas in residential soil,it was subsoil>deep soil>topsoil.The arsenic concentration variation at near distances from industrial areas was topsoil>subsoil>deep soil,contrasting with medium to far distances from industry(subsoil>deep soil>topsoil).Therefore,these findings can be utilized to prioritize remediation efforts and provide input for future research on arsenic contamination in the region.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 41302209)the National groundwater investigation project (Grant No.1212011121169)
文摘This thesis focuses Arsenic(As) distribution and occurrence in groundwater of Yangtze River Delta economic region, East China. 2019 groundwater samples were collected to analyze 26 chemical compositions, including As. The Principal Component Analysis(PCA) was used to find out As source in groundwater. The results show that average As concentration in groundwater of this study is 9.33 μg/l, and maximum As concentration is up to 510 μg/l. The variation coefficient is 314.34%. High arsenic phreatic water(>10 μg/l) distributes along the Yangtze River and its estuary. Weak hydrodynamic conditions, wide p H value variation range and deteriorating environment are dominating factors, especially in Yangtze River Delta. The PCA suggests that arsenic in phreatic water is mainly of natural origin. Part of arsenic may directly originate from sediment organics and be related to organics decomposition.
文摘The relevance of groundwater hydrogeochemistry to explain the occurrence and distribution of arsenic in groundwater is of great interest.The insightful discussions on the control of shallow groundwater(<50 m)hydrogeochemistry in arsenic mobilization are known to be a viable tool to explain the arsenic menace in shallow groundwater.The present investigation emphasizes the hydrogeochemical driver and/or control over the reductive dissolution of Fe-bearing host minerals and thereby releasing arsenic into the shallow groundwater of the study area.The study suggests that hydrogeochemical evolution is mainly governed by carbonate minerals dissolution,silicate weathering,and competitive ion-exchange processes in the shallow aquifers(<50 m).The present study also indicates the prevalence of carbonate minerals dissolution over silicate weathering.The emergence of Cl^(-)concentration in the shallow groundwater founds the possibilities of anthropogenic inputs into the shallow aquifers(<50 m).The reducing environment in shallow aquifers(<50 m)of the study area is evident in the reductive dissolution of Febearing shallow aquifer minerals which absorb arsenic in the solid phase and mobilize arsenic onto shallow groundwater.The study opted for many statistical approaches to delineate the correlation among major and minor ionic constituents of the groundwater which are very helpful to understand the comprehensive mechanism of arsenic mobilization into shallow groundwater.
基金The study was funded by the National Natural Science Foundation of China(41672225 and 41902243)the Natural Science Foundation of Jiangxi Province(20202BABL211018)the East China University of Technology Research Foundation for Advanced Talents(DHBK2019098).
文摘Groundwater with high arsenic(As) content seriously threatens human life and health. Drinking high-As groundwater for a long time will lead to various pathological changes such as skin cancer, liver cancer,and kidney cancer. High-As groundwater has become one of the most serious environmental geological problems in China and even internationally. This paper aims to systematically summarize the sources,migration, distribution, toxicological effects, and treatment techniques of As in natural groundwater in China based on a large number of literature surveys. High-As groundwater in China is mainly distributed in the inland basins in arid and semi-arid environments and the alluvial and lacustrine aquifers in river deltas in humid environments, which are in neutral to weakly alkaline and strongly reducing environments.The content of As in groundwater varies widely, and As(Ⅲ) is the main form. The main mechanism of the formation of high-As groundwater in China is the reduced dissolution of Fe and Mn oxides under the action of organic matter and primary microorganisms, alkaline environment, intense evaporation and concentration, long-term water-rock interaction, and slow groundwater velocity, which promote the continuous migration and enrichment of As in groundwater. There are obvious differences in the toxicity of different forms of As. The toxic of As(Ⅲ) is far more than As(V), which is considered to be more toxic than methyl arsenate(MMA) and dimethyl arsenate(DMA). Inorganic As entering the body is metabolized through a combination of methylation(detoxification) and reduction(activation) and catalyzed by a series of methyltransferases and reductases. At present, remediation methods for high-As groundwater mainly include ion exchange technology, membrane filtration technology, biological treatment technology, nanocomposite adsorption technology, electrochemical technology, and so on. All the above remediation methods still have certain limitations, and it is urgent to develop treatment materials and technical means with stronger As removal performance and sustainability. With the joint efforts of scientists and governments of various countries in the future, this worldwide problem of drinking-water As poisoning will be solved as soon as possible. This paper systematically summarizes and discusses the hot research results of natural high-As groundwater, which could provide a reference for the related research of high-As groundwater in China and even the world.
文摘Sixteen samples of surface and groundwater from the most southern part of the Hanoi city (Vietnam) has been taken and analyzed for the soluble major ions, namely Na+, K+, , Ca2+, Mg2+, Cl-, , and arsenic as well as molybdenum content along with isotopic composition of deuterium and oxygen (δ2H and δ18O), tritium activity, and δ13C in DIC. The stable isotopic composition of groundwater indicates the water in that area is recharged from the local meteoric and theRed River’s water sources. The mean residence time of the groundwater should be before 60-ies of the past century as its 3H activity ranged from LOD of the analytical technique (0.4 TU) to 2.1 TU only implying that As would not be related to its recent application. The concentrations of As in the water samples is weakly correlated with those of Fe2+ (R2 = 0.08) but it strongly did with the concentrations of bicarbonate (R2 = 0.80). Thus, bicarbonate seems to liberate As adsorbed on hydrous ferric oxides (Hfo) into water through the displacement mechanism. The surface adsorption-desorption of As could be proven by a strong correlation between As and Mo concentrations (R2 = 0.77). The bicarbonate formation in groundwater was thought to be, partly, due to the bio-mineralization of natural organic matter (NOM) by bacteria followed by the dissolution of calcite and/or dolomite present in the sediments. Evidence for the NOM bio-mineralization was found in the close relationship between δ13C and the concentration of bicarbonate in water. Therefore, the mobilization of As in groundwater of bicarbonate type in the southern part of Hanoi city seems to be not only due to the reductive dissolution of the Hfo but the bicarbonate displacement also should be considered.
基金supported by the National Natural Science Foundation(Nos.52000024 and 41907335)the Natural Science Foundation of Shanghai(No.23ZR1400700).
文摘The arsenic(As)release from sediments in great lakes is affected by various factors.In this study,the characteristics of As release fromsediments was investigated,and the As sources and sinks with the strengths in sediments from different areas(grass-type,algae-type,and grass-algae alternation areas)in great shallow lakes(Taihu Lake,China)were analyzed,and the influence of P competition in the process of As release was also studied.The results showed that changing trend of the values of equilibrium As concentration in sediments were consistent with the regional changes(0 to 28.12μg/L),and the sediments from algaetype areas had the higher values.The sediments from western lake and northwest lake bay were a strong As and a weak P source,and the north lake bay had the opposite trend of these two regions.Intense P source competition with As from the sediments occurred in algae-type areas.The grass-type areas had strong As and P retention capacities,indicating a sink role of sediment with high As and P sorption capacities.The degree of As and P saturation had similar trend in sediments,and the grass-type areas had the higher values,18.3%-21.4%and 15.31%-20.34%,respectively.Contribution analysis results showed that most of As release contribution was from the bottom(30-50 cm)sediments,and the surface(0-10 cm)sediments from algae-type areas contributed more to the overlying water than other region.
文摘The problem of arsenic(As)poisoning in the upper deltaic plains of the Ganges-Bhagirathi river system of West Bengal(WB),India,is terrifying. Elevated As(】50 ppb)in well water was observed within a depth range of 10-30 m in older grey terraces of abandoned fluvial channel deposits in the Murshidabad and Malda districts in WB.Both surface and cored(2-20 m)sediment samples from banks of the river Ganges and along a north-south transect of the main tributary Bhagirathi-Hooghly river
基金supported by National Natural Science Foundation of China(No.51077062)
文摘A simple negative ion mobility spectrometer （IMS） is designed and used to investi- gate the factors that influence the number and efficiency of electrons generated by the needle-ring pulsed corona discharge electron source. Simulation with Ansoft Maxwell 12 is carried out to analyze the electric field distribution within the IMS, and to offer the basis and foundation for analyzing the measurement results. The measurement results of the quantities of electrons show that when the drift electric field strength and the ring inner diameter rise, both the number of ef- fective electrons and the effective electron rate are increased. When the discharge voltage becomes stronger, the number of effective electrons goes up while the effective electron rate goes down. In light of the simulation results, mechanisms underlying the effects of drift electric field strength, ring inner diameter, and discharge voltage on the effective electron number and effective electron rate are discussed. These will make great sense for designing negative ion mode IMS using the needle-ring pulsed corona discharge as the electron source.
文摘Arsenic is usually associated with sulphide minerals formed in the geothermal environment. However, sulphide minerals are prone to dissolution after contact with meteoric water under surface oxidizing conditions. Secondary precipitates that form from the dissolution of the primary sulfides exert a greater influence on arsenic mobility in the geothermal environment. Fe-hydroxides have very good affinity with dissolved arsenate and are stable under most surface oxidizing conditions. Both amorphous silica directly precipitated from geothermal fluids and possibly a kaolinite alteration can host a small significant amount of arsenic. These silicates are also more stable under a wide range ofpH and redox conditions.
文摘We propose an on-demand multipath routing algorithm in a mobile ad hoc network for video transmission and evaluate its real world performance in video streaming application. There have been a number of multipath routing protocols extended from AODV which is a well-known single path routing protocol. Multipath routing protocols indicate good performance in the reduction of route discovery latency and unnecessary routing packets in simulations. We show that the route establishment using source route lists provided by us (Hu and Johnson, 2002) can reduce the route discovery latency, select stable routes automatically, and work well for live video streaming without limitation of the hop count based approaches. We evaluate this proposed method compared with the original AODV by using eight laptop PCs and demonstrate live streaming experiments.
基金supported by the Open Research Fund of Jiangsu Collaborative Innovation Center for Smart Distribution Network (XTCX202001)National Natural Science Foundation of China (52077061)。
文摘In an integrated energy system(IES) composed of multiple subsystems, energy coupling causes an energy supply blockage or shutdown in one subsystem, thereby affecting the energy flow distribution optimization of other subsystems.The energy supply should be globally optimized during the IES energy supply restoration process to produce the highest restoration net income. Mobile emergency sources can be quickly and flexibly connected to supply energy after an energy outage to ensure a reliable supply to the system, which adds complexity to the decision. This study focuses on a powergas IES with mobile emergency sources and analyzes the coupling relationship between the gas distribution system and the power distribution system in terms of sources, networks, and loads, and the influence of mobile emergency source transportation. The influence of the transient process caused by the restoration operation of the gas distribution system on the power distribution system is also discussed. An optimization model for power-gas IES restoration was established with the objective of maximizing the net income. The coordinated restoration optimization decision-making process was also built to realize the decoupling iteration of the power-gas IES, including system status recognition, mobile emergency source dispatching optimization, gas-to-power gas flow optimization, and parallel intra-partition restoration scheme optimization for both the power and gas distribution systems. A simulation test power-gas IES consisting of an 81-node medium-voltage power distribution network, an 89-node medium-pressure gas distribution network, and four mobile emergency sources was constructed. The simulation analysis verified the efficiency of the proposed coordinated restoration optimization method.
基金supported by the National Key Research and Development Program of China(No.2017YFC1502504)the National Natural Science Foundation of China(No.41877531).
文摘With the increasing severity of arsenic(As)pollution,quantifying the environmental behavior of pollutant based on numerical model has become an important approach to determine the potential impacts and finalize the precise control strategies.Taking the industrialintensive Jinsha River Basin as typical area,a two-dimensional hydrodynamic water quality model coupled with Soil andWater Assessment Tool(SWAT)model was developed to accurately simulate the watershed-scale distribution and transport of As in the terrestrial and aquatic environment at high spatial and temporal resolution.The effects of hydro-climate change,hydropower station construction and non-point source emissions on Aswere quantified based on the coupled model.The result indicated that higher As concentration areas mainly centralized in urban districts and concentration slowly decreased from upstream to downstream.Due to the enhanced rainfall,the As concentration was significantly higher during the rainy season than the dry season.Hydro-climate change and the construction of hydropower station not only affected the dissolved As concentration,but also affected the adsorption and desorption of As in sediment.Furthermore,As concentration increased with the input of non-point source pollution,with the maximum increase about 30%,resulting that non-point sources contributed important pollutant impacts to waterways.The coupled model used in pollutant behavior analysis is generalwith high potential application to predict and mitigate water pollution.
文摘The goal of this study is to analyze the relative contribution of different emission source categories to ozone in the Houston-Galveston-Brazoria (HGB) area of Texas. Emission Processing System (EPS3) is used to prepare the emission files for five different source combination cases (Base case, Biogenic, Area + Biogenic, Mobile + Biogenic, Low-level Point + Biogenic). These emission files are used to perform photochemical modeling with Comprehensive Air Quality Model with Extensions (CAMx), and the results are analyzed with Visual Environment for Rich Data Interpretation (VERDI) tool. The daily maximum ozone concentrations and individual contributions of the source categories were analyzed over a 15-day study period between June 1-15, 2012, at three locations (University of Houston-Sugarland, Bayland Park and Conroe). Biogenic sources contributed an average of 49.7% ± 12.8%, 43.1% ± 12.0%, and 39.9% ± 9.28% at Sugarland, Bayland Park and Conroe sites respectively, indicating the significance of isoprene emissions from the vegetation in northeast Houston. On peak ozone days, contribution of Mobile + Biogenic source category averages about 80.1% ± 12.6%, 79.9% ± 6.50%, and 75.9% ± 10.9% at Sugarland, Bayland Park and Conroe sites respectively, indicating the dominance of mobile source NOX emissions and the necessity for regulatory focus on mobile source emissions control.
文摘There exists a lack of detailed empirical studies to assess the relevance of WebMapping applications. Despite this fact, it is quite common to note that importance and influence of WebMapping applications have increased over the last years. This paper presents the result of an empirical study to analyze the importance of a Desktop-WebMapping application for a gastronomic web 2.0 portal for the city of Osnabrück. An exploratory focus is to evaluate how often geospatial information (in a broader information context) from this web portal is used and how important the WebMapping applications are for the users of the web portal. Furthermore, it is evaluated which WebMapping functions (e.g. routing, queries, printing) are of relevance to the users and what the order of importance is for the provided functions. To-date, just a few mobile WebMapping applications for handheld devices exist. Consequently, for OsnaGo we developed a mobile WebMapping component that can be used with mobile phones, PDAs and other handheld devices to access the web portal (http://www.osnago-mobil.de). Development and user based evaluation is presented in this paper.
文摘During a routine inspection in a petroleum product terminal, hydrocarbon staining was found in soil along the perimeter of a diesel fuel tank. As the observation was made a few days after a magnitude 5.1 earthquake in the general area of the terminal, the hydrocarbon staining in the soil was suspected to be a result of a leak from the tank. The observation triggered an immediate tank inspection, which included examination of tank exterior, piping and connections;pressure testing;wall thickness gauging;and an inventory check. Results of the initial inspection suggested that there were no integrity issues with the tank. Before more vigorous and more disruptive inspections were conducted, chemical fingerprinting was conducted to assess the nature of soil staining and potential connection with the “suspected” tank leak. Samples were collected from the site, including a diesel fuel sample from the tank, a light non-aqueous phase liquid (LNAPL) sample from the monitoring well in the immediate vicinity, and representative soil samples from the perimeter of, and beneath, the tank. A tiered laboratory analytical approach was taken, which included initial gas chromatography-flame ionization detector carbon chain analysis and final gas chromatography-mass spectrometry or detailed fingerprint analyses. Based on the results of initial inspection, knowledge of LNAPL mobility in response to earthquake seismic waves, and chemical fingerprints of representative samples, it was determined that the soil staining was not a result of suspected tank release but remobilization of hydrocarbons from the historically impacted soil beneath the tank to the soil along the perimeter of the tank.
基金The work was financially supported by China Geological Survey(Grant No.DD202201756,DD20230428).
文摘Arsenic(As),fluoride(F^(−))are both ubiquitous in groundwater,and co-exposure to these elements through contaminated drinking water may cause detrimental effects on human health more in comparison with individual exposure.As,F^(−)co-occurrence in groundwater of the inland plain in Huaihe River Basin,China is a major concern,where inhabitants are rely on groundwater as the leading water source for drinking to date.This work employs an approach of hydrochemical analysis and modelling to identify the possible origin of As and F^(−),to analyze co-enrichment mechanism,and to estimate the associated exposure risk.The results shows presence of elevated As and F^(−)concentrations is an important factor affecting groundwater quality from 62 groundwater samples.The recorded As concentrations vary from 0.23 to 20.40μg/L,with a mean of 5.95μg/L,F^(−)concentrations vary from 0.54 to 2.60μg/L,with a mean of 1.29 mg/L,and 8%of samples are simultaneously above their permissible limits in drinking water by the WHO.Groundwater with As,F^(−)co-contamination is occurred within reducing and alkaline aquifers,and its chemical type is HCO_(3)–Na.The hydrochemical processes involved in the co-contamination are reductive desorption,evaporation,and ion exchange,which are controlled by local geology,geomorphology,and hydrochemistry.Groundwater As is derived and released by reductive desorption and F^(−)is mainly originated by fluorite dissolution.Groundwater As,F^(−)are geogenic sources,and the mechanisms for co-contamination are associated with high elemental abundance,flat terrain,alkaline and reductive groundwater conditions.The research provides a case study about groundwater As,F^(−)co-contamination,which may be enhance understanding the co-enrichment mechanism in semi-humid areas.
文摘The paper investigated a new method of analyzing perfume odors.The study adopted IMS with glow dischargeas ion source and with positive ion mode.We got the quality characteristics of perfume odors in this way without any collection and concentration process.The quality of perfume odors can be identified by IMS peak characteristics,and the characteristics of different quality of perfume also can be identified.In summary,the IMS is an effective technique in the perfume odor detection,it is also a new way of gas sample analysis.
文摘A number of natural experiments have recently found that COVID-19 restrictions imposed in nations worldwide are correlated with short-term reductions—in some cases dramatic reductions—in mobile-source air pollutants. Noticeably absent from these studies are estimates of the social net benefits associated with the changes in human behavior underlying the pandemic-induced effects. Using readily available data provided by the state of Utah and the U.S. Environmental Protection Agency’s Co-Benefits Risk Assessment Health Impacts Screening and Mapping Tool (COBRA), we find that daily social net benefit was positive during a pandemic-induced shutdown from March to April, 2020 in Utah’s Wasatch Front region solely when COBRA’s “high” health benefit estimate from combined reductions in PM<sub>2.5</sub> and NO<sub>x</sub> concentrations are weighed against the region’s “low” vehicle-trip cost estimate. All other scenarios correspond with negative net benefit estimates, <i>i.e.</i>, when high and low benefit estimates of reductions solely in PM<sub>2.5</sub> concentrations as well as for combined reductions in PM<sub>2.5</sub> and NO<sub>x</sub> concentrations are weighed against the region’s high vehicle-trip cost estimate. Generally speaking, social net benefits are higher for two of the Wasatch Front’s four counties.
基金supported by the National Natural Science Foundation of China(No.42276155)the Taishan Scholars Program,Shandong Provincial Natural Science Foundation(No.ZR2020QD131)+1 种基金the Research Program of CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation(No.1189010002)the Key R&D Program of Shandong Province,China(No.2022CXPT019).
文摘Antibiotic resistance genes(ARGs)might have great effect on ecological security and human health.Oceans are important reservoirs that receive tremendous amounts of pollutants globally.However,information on the proliferation of ARGs in seawater is still limited.This study performed field sampling to investigate the occurrence and distribution of ARGs in seawater of the South China Sea,which is the deepest and largest sea in China.The results showed that the total absolute abundances of ARGs in seawater samples ranged from 2.1×10^(3)to 2.3×10^(4)copies/mL,with an of 5.0×10^(3)copies/mL and a range of 2.2×10^(3)–1.8×10^(4)copies/mL for those with mobile genetic elements(MGEs).Genes resistant to multidrug,aminoglycoside,tetracycline,and fluoroquinolone antibiotics accounted for 77.3%–88.6%of total ARGs in seawater.Proteobacteria and Cyanobacteria represented 32.1%–56.2%and 30.4%–49.5%of microbial community,respectively.Prochlorococcus_MIT9313 and Clade_la were the prevalent genera in seawater of the South China Sea.Complex co-occurrence relationship existed among ARGs,MGEs,and bacteria.Anthropogenic activities had critical influence on ARGs and MGEs.Hospital wastewater,wastewater treatment plant effluent,sewage,aquaculture tailwater,and runoff were determined as the important sources of ARGs in seawater of the South China Sea based on positive matrix factorization analysis.
基金funded by the Research and Community Service Institute(LPPM),Institut Teknologi Bandung,Indonesia through the“Riset Unggulan”Program for the year 2023.
文摘This research investigates the arsenic concentrations in 96 soil samples from a regency in Indonesia using a statistical approach.Soil samples were collected from three depth layers(topsoil[10e20 cm],subsoil[50e60 cm],and deep soil[90e100 cm]),with each layer consisting of 32 samples.Statistical analysis using SPSS was employed to analyze potential arsenic sources based on the proximity of study locations to geothermal system areas,land use,distance from industry,and the presence of study locations on fault lines.The findings indicate that the potential source of arsenic contamination in the soil are suspected to be associated with geothermal system activities and the presence of soil samples on fault lines.The arsenic concentration in locations near to the geothermal system(5-10 km)was 45 times higher(OR=45,95%CI=45e362.57,p<0.01).Arsenic was found to be 3.828 times higher in study areas situated on fault zones(OR=3.828,95%CI=1.507e9.719,p<0.01).Additionally,the research suggests that arsenic in the soil may also originate from anthropogenic activities,such as agriculture and industry,as the highest concentrations were found in subsoil or topsoil layers compared to deep soil.The variation in arsenic concentration from highest to lowest in agricultural soil layers was subsoil>topsoil>deep soil,whereas in residential soil,it was subsoil>deep soil>topsoil.The arsenic concentration variation at near distances from industrial areas was topsoil>subsoil>deep soil,contrasting with medium to far distances from industry(subsoil>deep soil>topsoil).Therefore,these findings can be utilized to prioritize remediation efforts and provide input for future research on arsenic contamination in the region.
