Analysis on the Chemical Characteristics of Shallow Groundwater and Causes of Formation in the Area around Poyang Lake

[Objective] The study aimed at analysing the chemical characteristics of shallow groundwater and causes of formation around Poyang Lake area. [Method] The quality of shallow groundwater under seven counties or cities around Poyang Lake was investigated in 2010, and compared different regions from salinity, hardness, conductivity, hydrochemistry types and so forth, so as to reveal the status quo, change characteristics and reasons of shallow groundwater. [Result] Except for pH, other water quality indicators of shallow groundwater around Poyang Lake were better, attaining Class I water quality standards. Among these regions, the salinity, hardness, conductivity, Na+, K+, Ca2+, Mg2+, Cl- and HCO-3 concentration of shallow groundwater in Nanchang city were up to the maximum values, while pH and SO2-4 concentration were the highest in Duchang County; Mg2+ concentration and pH were the lowest in Poyang County, and hardness, K+, Ca2+, SO2-4 and Cl- concentration in Yongxiu County reached the minimum values, while Na+ concentration, salinity and conductivity were the lowest in Jinxian County. In addition, the better quality of groundwater around Poyang Lake was closely related to the low level of economic development in Jiangxi Province. Meanwhile, many water quality indices in Nanchang City reached the maximum values, and even tended to Class Ⅱ water quality standards, which resulted from the high level of economic development and decisive role of human activities. [Conclusion] The research could provide references for the establishment of management strategies for regional shallow groundwater.

Hydrochemical characteristics and geochemistry evolution of groundwater in the plain area of the Lake Baiyangdian watershed,North China Plain

Water cycle and water quality in the Lake Baiyangdian watershed of the North China Plain have undergone great changes due to over-pumping of groundwater and wastewater discharge.In this paper,hydrogeochemical data was collected to analyze the hydrochemical characteristics and geochemistry evolution of groundwater.The study area was divided into two typical parts.One was in the upstream plain area,where over-pumping had resulted in significant decline of groundwater level;the other one was located in the downstream area near the Fu River and Lake Baiyangdian(Lake BYD region).In addition to the natural weathering of minerals,excessive fertilizer was also a main factor of higher ion concentration in groundwater.According to studies,due to good permeability,these regions were easy to be polluted even with deep groundwater depth.However,upstream shallow groundwater and surface water,including lake water,domestic along with industrial wastewater were all sources of present shallow groundwater in the Lake BYD region.Results indicated that anthropogenic activities rather than minerals much matter to the groundwater in these regions.Particularly,wastewater largely decided the groundwater quality,which suggested that the management and restoration of surface water quality was crucial to groundwater protection.

Study on hydrochemical characteristics and formation mechanism of shallow groundwater in eastern Songnen Plain

Under the influence of global climate changes and human activities, the Songnen Plain's groundwater environment is deteriorating, which becomes an important factor restricting the social economic development and ecological balance. As a relatively independent water system in the Songnen Plain, the groundwater system of the Songhua River provides the main water sources for industry, agriculture, life and other aspects. According to the hydrogeological investigation, groundwater sample collection and testing in the eastern Songnen Plain, descriptive statistics analysis, piper diagram, Gibbs diagram and reverse hydrogeochemical simulation were used to analyze the hydrochemical characteristics and evolution laws of regional groundwater. The results of this study show that HCO_3^- and Ca^(2+) are the main anion and cation in the groundwater; the formation of groundwater chemical components are controlled by topographic and geomorphic factors and groundwater occurrence conditions; groundwater subarea of the Lalin-Ashi River is mainly controlled by weathering-dissolution process, and evaporation and ion-exchange reactions are more obvious in groundwater subarea of the Hulan-Tongken River, whose chemical composition also affects the valley plain groundwater subarea in the discharge area; in addition, local high intensity withdrawal causes abnormal hydrochemical evolution processes. The research results can offer scientific basis for rational utilization and protection of groundwater.

Hydrochemical characteristics and water quality evaluation of shallow groundwater in Suxian mining area,Huaibei coalfield,China

The aim of this study is to evaluate the hydrogeochemical characteristics and water environmental quality of shallow groundwater in the Suxian mining area of Huaibei coalfield,China.The natural formation process of shallow groundwater in Suxian is explored using Piper trilinear charts and Gibbs diagrams,and by examining the ratios between the major ions.United States Salinity Laboratory(USSL)charts,Wilcox diagrams,and the water quality index(WQI)are further employed to quantify the differences in water quality.The results reveal that the main hydrochemical facies of groundwater are HC03-Ca,and that silicate dissolution is the main factor controlling the ion content in shallow groundwater.The USSL charts and Wilcox diagrams show that most of the water samples would be acceptable for use in irrigation systems.The WQI results for each water sample are compared and analyzed,and the quality of groundwater samples around collapse ponds is found to be relatively poor.

Analysis on hydrochemical characteristics of groundwater in strongly exploited area in Hutuo River Plain

The Hutuo River alluvial-proluvial fan is located in North China Plain, and groundwater is the main source of water supply for agriculture and domestic water. Shijiazhuang depression funnels due to the long-term excessive exploitation are the bottleneck of the regional economic development. Analyzing the chemical characteristics of groundwater under the condition of strong human activities, can provide a scientific basis for further study of strong groundwater mining area environmental change. 143 groups of shallow groundwater samples are collected during the period of 2007-2008. In this paper, the hydrochemical characteristics of groundwater in the Hutuo River Plain area are analyzed systematically, using hydrogeochemical theory, combined with statistical methods and hydrochemical methods. Results are shown as follows: HCO_3^- and Ca^(2+) are major anion and cation. The variation coefficients of K^+, Ca^(2+), Mg^(2+) and HCO_3^- between 0.25 and 0.52, which means small and stable relatively. The variation coefficient of are Na^+, NO_3^-, Cl-, SO2-4 were large(0.89-1.01). They are sensitive and vulnerable to environmental change affect. Due to the impact of human activities, from the top to the edge of the alluvial-proluvial fan, the hydrochemical types of groundwater change from single to multiple, followed by HCO_3^-Ca·Mg, HCO_3·SO_4-Ca·Mg, HCO_3·SO_4·Cl-Ca·Mg, HCO_3·Cl-Ca·Mg and other types.

Characteristics of the main inorganic nitrogen accumulation in surface water and groundwater of wetland succession zones

Based on the observation of a complete hydrological year from June 2014 to May 2015, the temporal and spatial variations of the main inorganic nitrogen (MIN, referring to NO3^--N, NO2^--N, NH4^+-N) in surface water and groundwater of the Li River and the Yuan River wetland succession zones are analyzed. The Li River and the Yuan River are located in agricultural and non-agricultural areas, and this study focus on the influence of surface water level and groundwater depth and precipitation on nitrogen pollution. The results show that NO3^--N in surface water accounts for 70%-90% of MIN, but it does not exceed the limit of national drinking water surface water standard. Groundwater is seriously polluted by NH4^+-N.Based on the groundwater quality standard of NH4^+-N, the groundwater quality in the Li River exceeds Class III water standard throughout the year, and the exceeding months' proportion of Yuan River reaches 58.3%. Compared with the Yuan River, MIN in groundwater of the Li River shows significant temporal and spatial variations owing to the influence of agricultural fertilization. The correlation between the concentrations of MIN and surface water level is poor, while the fitting effect of quadratic correlation between NH4^+-N concentration and groundwater depth is the best (R^2=0.9384), NO3^--N is the next (R^2=0.5128), NO2^--N is the worst (R^2=0.2798). The equation of meteoric water line is δD =7.83δ^18O+12.21, indicating that both surface water and groundwater come from atmospheric precipitation. Surface infiltration is the main cause of groundwater NH4^+-N pollution. Rainfall infiltration in non-fertilization seasons reduces groundwater nitrogen pollution, while rainfall leaching farming and fertilization aggravate groundwater nitrogen pollution.

Dynamic Characteristics and Influencing Factors of Groundwater Level in Qianyang County

The dynamic characteristics and influencing factors of groundwater level in Qianyang County were analyzed.The results showed that in the south bank of the Qianhe River,the change of groundwater level was mainly affected by precipitation,and the response of the groundwater level to the change of precipitation was one year later.The groundwater level presented a downward trend on the whole.In the north bank of the Qianhe River,the supply source of the groundwater level included precipitation and hydrology,and the groundwater level showed a rising trend on the whole.In the plain area,there was a sudden change in the groundwater level under the control of human activities.In a word,the main factors influencing the groundwater level in various geological conditions were different,so there were great differences between various regions in the dynamic characteristics of the groundwater level in Qianyang County.

Distribution characteristics and source of BTEX in groundwater in Guangzhou,Guangdong Province,P.R.China

In order to find out the distribution characteristics of BTEX in groundwater, which include Benzene, Toluene, Ethylbenzene, p-Xylene, m-Xylene, and o-Xylene, 82 groups of groundwater samples and 10 surface water samples collected from Guangzhou in Guangdong during 2005 to 2008 were tested by gas chromatography and mass spectrum(GC/MS). The result showed that the BTEX concentration in groundwater does not exceed the standard. The detection rate of BTEX is 14.63% in groundwater, and the total BTEX concentration is lower than 9.5 μg/L. Of 6 kinds of BTEX, toluene had the highest detection rate(12.20%) and detection value(9.5 μg/L), which was followed by Benzene, with the detection rate of 3.65%, and detection value of 4.9 μg/L respectively; most of samples with BTEX are distributed in Huangpu district, Baiyun district, Huadu district and other industrialized areas; this spatial distribution and urban distribution have obvious consistency. With economic development, plant expansion and population growth led to a large amount of waste water discharge, and infrastructure construction is lagging behind, indicating that rapid urbanization is a major driving force of BTEX in groundwater, and through the analysis of a typical area, it is found that benzene system surface water infiltration was an important source of BTEX in groundwater of Guangzhou.

Analysis on temporal and spatial variations of groundwater hydrochemical characteristics in the past decade in southern plain of Beijing, China

Groundwater utilization and protection are crucial for sustainable urban development. This is especially true for Beijing, where groundwater is an important source for urban water supply. In this study, statistical methods, including descriptive statistics, correlation analysis, principal component analysis, and Piper-Tri-linear diagram, were used in analyzing the temporal and spatial variations of the hydrochemical characteristics of groundwater based on monitored data from the southern plain of Beijing, China. Results indicated consistent changes of groundwater's hydrochemical characteristics in different aquifers in the study area. The percentage of HCO_3^-in total anion increased significantly in the groundwater, and hydrochemical water type evolved gradually from Ca-Mg-Cl-SO_4 based to Ca-Mg-HCO_3 based from period 2005-2007 to period 2013-2015. In shallow groundwater, the concentration of Na^+, Ca^(2+), SO_4^(2-), HCO_3^-, and total dissolved solids(TDS) increased from period 2005-2007 to period 2013-2015, and the greatest change came from HCO_3^-, rising from 428.93 to 528.96 mgL^(-1). The changes of main ionic concentrations in the deep groundwater were consistent with those in the shallow groundwater for both periods. However, the variations in deep groundwater were less than those in shallow groundwater. The temporal and spatial variations of hydrochemical characteristics reflect the groundwater quality in the study area. This study could facilitate decision-making process on the protection of groundwater resources to ensure its sustainable utilization.

Characteristics of groundwater and urban emergency water sources optimazation in Luoyang,China

The construction of emergency water sources is the material basis for ensuring urban water safety,and it is also an inherent requirement for maintaining social stability and development.The hydrogeological characteristics of groundwater in Luoyang City from the aspects of the division of groundwater aquifer groups,water yield property and groundwater dynamics were described in this paper.Two emergency water sources were selected on basis of comprehensively considering groundwater resources and ecological environmental effects,groundwater quality and exploitation technology,etc.Then it further analysed the aquifer types,water yield properties and groundwater recharge,runoff and discharge conditions of the two emergency water sources,and evaluate the groundwater resources quantity of the water sources.The results are that the shallow underground aquifer in Luoyang City is thick,coarse,and stable in lithology and thickness.The two water sources enjoy good exploitation potential and can be used as backup water sources to supply water in the event of a water source crisis.

Variation characteristics of aquifer parameters induced by groundwater source heat pump operation under variable flow

The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of building air conditioning load were considered.The results,compared with the constant flow operation,indicate that the influence on the variations of porosity,hydraulic conductivity and confined water head is decreased by 48%,51% and 71%,respectively,under variable flow operation.The security of variable flow operation is superior to that of constant flow.It is also concluded that the climate region and function of the buildings are primary factors which affect the suitability of variable flow operation in GWSHP.

Evaluation of hydrogeochemical characteristics of groundwater in parts of the lower Benue Trough,Nigeria

The aim of this work is to evaluate the hydrogeochemical characteristics of groundwater in parts of the lower Benue Through in Nigeria as well as to evaluate the variation in groundwater chemistry data and the suitability of the groundwater for drinking and other domestic purposes.This was based on chemical analyses of 44 water samples from existing wells and boreholes in the study area.From the statistical analysis(wide ranges,median and standard deviation),it is obvious that there are significant variations in the quality/composition of groundwater in the period of sampling.The calculated SAR,Na% and RSC values indicated that the water is of excellent to good quality and is suitable for irrigation.Na and HCO3 are dominant with respect to the chemical composition of the groundwater.On the basis of water chemistry,hydrochemical indices and factor analysis the dominant controls or processes affecting the distribution of geochemical variables in the study area have been shown to be water/rock interaction which is mainly controlled by carbonate and silicate dissolution as well as anthropogenic influence to a lesser extent.Additional processes include cation exchange reactions and reverse ion exchange to a minor extent.

Physico-Chemical and Bacterial Characteristics of Groundwater and Surface Water Quality in the Lagbe Town: Treatment Essays with <i>Moringa oleifera</i>Seeds

The river water and groundwater from Lagbe town in Benin Republic were collected and analyzed for physical, chemical and microbiological parameters. The surface water samples were treated with alum, Moringa oleifera seeds powder and the combination of alum and Moringa oleifera seeds. The jar-test essays were carried out with two water samples at initial turbidities 7.2 NTU and 14.4 NTU. The water samples analyzed are fairly mineralized (conductivity varies between 166 and 687 μS/cm), enough soft and contain the nitrate (104 mg/L for W4 sample). They are greatly polluted by pathogenic microorganisms such as Escherichia coli, Klebsiella, Enterococcus, Vibrio, Serratia. The optimal dosages of Moringa are 96 mg/L and 80 mg/L respectively. We have observed a reduction of 60% of turbidity and a substantial remove of all pathogenic microorganisms after water treatment with Moringa oleifera seeds. For the combination treatment, 93% of initial turbidity and 92% of initial concentration of organic matter in the sample E2 were eliminated. The pH remained almost constant during the treatment.

Statistical characteristics of heavy metals content in groundwater and their interrelationships in a certain antimony mine area

In recent years, most of domestic and foreign researches about heavy metal pollutions of metal mine mainly focus on water, soil and plants on the surface. There is lack of researches about heavy metal pollution in groundwater of metal mine. In this research, a certain antimony mine area is selected as a typical study area. Also, the study about statistical characteristics of heavy metals in groundwater has been carried out. Furthermore, the interrelationships have been preliminarily discussed through related analysis, such as relevant analysis, cluster analysis and principle component analysis. The results show that: the excessive elements in groundwater of study area are Sb, As, Pb, Se, and Ni. The average mass concentration of Sb, As, and Pb is higher than that of drinking water standards(GB5749-2006). The concentration of most heavy metals in dry season is lower than or equal to that in wet season for groundwater. Zn is the only metal in groundwater showing a different pattern, the concentration of which in dry season is higher than that in wet season. Under the impacts of stratum leaching and absorption effect, the concentration of heavy metals(except Pb and Ba) in groundwater are lower than or equal to that in surface water. As and Se, the two heavy metals have a significant positive correlation, which shows the two elements might have gone through similar environmental geochemical effect. Also, the connection among Zn, Hg, Pb, and Mn is not obvious; therefore, the sources of those elements are quite different. In addition, the elements of Se and As have obvious positive interrelationship with elements of CO_3^(2-) and F^-. Also, the Pb has significant positive correlation with PO_4^(3-), H_2SiO_3 and oxygen consumption. The results of cluster analysis show that 9 different heavy metals in the study area can be divided into 3 categories: Zn, Cd, Mn, Hg, Cu, and Cr belong to the first category, Se and As belong to the second one, and the last category is Pb. Also, the principle component analysis divides 6 heavy metals(Zn, As, Hg, Pb, Mn, and Se) into 4 different principle components, which can be utilized to assess heavy metals pollution situations in groundwater. The reliability of this method is higher than 91%. Moreover, the research provides theory basis and models for establishing evaluation index system and exploring the evaluation method of heavy mental pollution in groundwater.

Factors Influencing the Shallow Groundwater Quality in Four Districts with Different Characteristics in Urban Area (Douala, Cameroon)

This study examines groundwater samples from four areas under different conditions. Variations amongst the areas are due to the distinct topography, demographics, and socio-economic activities. A qualification of the groundwater using the following parameters;pH, electric conductivity and nitrate analysis yielded results depicting the deplorable state of the unconfined aquifer;which is even worst in the densely populated and low-lying areas. These unfavorable conditions are present in the older districts (Bependa and Ndogbong) compared to the younger and least populated (urbanized) districts (Ndogpassi and Logpom). The poor quality of groundwater could be due to contamination by sewage from latrines and surface discharges. Nevertheless, nitrate contents (>241 mg/l) in these districts indicate that pollution has not reached the alarming levels observed in other West African cities (nitrates > 400 mg/l). Relatively low concentrations of nitrate in groundwater of the studied areas could be due to volatilization phenomena common in the unconfined aquifers in Douala. We however remarked that most of the studied wells are not used as drinking water, because they present particular health risks to humans.

Evaluation of groundwater geochemical characteristics and quality in the central and Northern Shaanxi Province,China

Groundwater is of vital importance to many aspects of ecosystem services,especially in the central and northern Shaanxi Provence,China,-an area covered by loess deposits and short of water resources.We studied the solute geochemistry and water quality of groundwater in this area to improve the understanding of hydrogeochemical processes in loess deposits area.The results showed that the average pH of groundwaters was 8.03±0.36(1 SD)with large ranges(324-83,379 mg/L)of the total dissolved solids(TDS).The cations and anions followed the order of Na^+>Ca^2+>Mg^2+>K^+>SiO2 and HCO3>Cl^->SO4^2->F^->NO3^-.Most groundwater samples show the HCO3^--Na^+-Ca^2+water type and a small number of samples the Na^+-Cl^-type.Irrigation water quality assessments showed that 40%of the groundwater has good water quality,42%moderate water quality,and 18%(the upper reaches of Wuding River and Wei River)poor water quality with very high salinity.About 40%of groundwater samples were not suitable for drinking due to the high TDS,fluoride,sulfide,and chloride.Gibbs plot and stoichiometry analysis showed that carbonate weathering is the main source of groundwater chemistry in central Shaanxi Province while evaporite dissolution dominates in northern Shaanxi Provence.The loess weathering significantly influences the dissolved solutes of groundwater in the Loess Plateau.The ion-exchange between Mg^2+and Ca^2+in groundwater and Na^+in clay minerals and the deposition of carbonate minerals increased Na^+but decreased the Ca^2+in groundwater.Our research results improve our understanding of hydrogeochemical processes that affect the solutes chemistry of groundwater in the loess area and provide essential data to the global groundwater database.

Characteristics and Methods of Groundwater Environmental Impact Assessment in Mining Areas of Guizhou Province:A Case Study of Zhijin Area of Zhina Mining Area

In Guizhou Province,karst areas and springs are widely distributed,and hydrogeological conditions are complex in mining areas. Usually there are many hydrogeological units in a mining area,and the hydrogeological conditions are very different from that of most northern mining areas in China. In view of the uniqueness of mining areas in Guizhou Province,taking Zhijin area of Zhina mining area as an example,the planning characteristics of mining areas and characteristics of groundwater environment in Guizhou Province were analyzed firstly,and then the characteristics and key considerations of groundwater environmental impact assessment in mining areas of Guizhou Province were studied. For example,when the height of water flowing fractured zone,impact radius,and the amount of water resources affected are calculated,it is necessary to analyze and evaluate as many typical mines as possible. The impact on springs as the sources of residents＇ drinking water should be analyzed one by one.