首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 72 毫秒
1.
Agricultural activities act as dominant polluter of groundwater due to increased fertilizers and pesticides usage. Bist-Doab region, Punjab, India, is one such region facing deterioration of groundwater quality due to usage of fertilizers. This study aims in delineating and evaluating the groundwater quality in the region. Water samples are collected from canals, reservoir, and shallow and deep groundwater. Water types in canal and reservoir in Kandi region are Mg2+HCO3 ? and Mg2+Ca2+Na+HCO3 ?, respectively. While water types of shallow and deep groundwaters are found to be of two types: Na+Mg2+Ca2+HCO3 ? and Ca2+Mg2+Na+HCO3 ?. Presence of Mg2+ in groundwater at locations adjoining canals indicates recharge due to canal. The major ion (Na+, Mg2+, Ca2+, HCO3 ?) chemistry of the region is due to weathering of rocks that are rich in sodic minerals and kankar. Deep groundwater quality in the region meets BIS and WHO standards for drinking purpose, unlike shallow groundwater which is of poor quality at many locations. Both shallow and deep groundwater with high sodium concentration (>1.5 meq/l) affect cropping yield and permeability of soil matrix. High concentration of SO4 2? and NO3 2? (>1 meq/l) in shallow groundwater at few locations indicates influence of anthropogenic (fertilizer) activity. Factor analysis indicates that the major cations, bicarbonate and chloride are derived from weathering/dissolution of source rocks. Higher concentration of nitrate and presence of sulphate in shallow groundwater at few locations is due to usage of fertilizers and pesticides.  相似文献   

2.
Groundwater survey has been carried out in the area of Gummanampadu sub-basin located in Guntur District, Andhra Pradesh, India for assessing the factors that are responsible for changing of groundwater chemistry and consequent deterioration of groundwater quality, where the groundwater is a prime source for drinking and irrigation due to non-availability of surface water in time. The area is underlain by the Archaean Gneissic Complex, over which the Proterozoic Cumbhum rocks occur. The results of the plotting of Ca2+ + Mg2+ versus HCO3 ? + CO3 2?, Ca2+ + Mg2+ versus total cations, Na+ + K+ versus total cations, Cl? + SO4 2? versus Na+ + K+, Na+ versus Cl?, Na+ versus HCO3 ? + CO3 2?, Na+ versus Ca2+ and Na+: Cl? versus EC indicate that the rock–water interaction under alkaline condition is the main mechanism in activating mineral dissociation and dissolution, causing the release of Ca2+, Mg2+, Na+, K+, HCO3 ?, CO3 2?, SO4 2? and F? ions into the groundwater. The ionic relations also suggest that the higher concentrations of Na+ and Cl? ions are the results of ion exchange and evaporation. The influences of anthropogenic sources are the other cause for increasing of Mg2+, Na+, Cl?, SO4 2? and NO3 ? ions. Further, the excess alkaline condition in water accelerates more effective dissolution of F?-bearing minerals. Moreover, the chemical data plotted in the Piper’s, Gibbs’s and Langelier–Ludwig’s diagrams, computed for the chloro-alkaline and saturation indices, and analyzed in the principal component analysis, support the above hypothesis. The groundwater quality is, thus, characterized by Na+ > Ca2+ > Mg2+ > K+: HCO3 ? + CO3 2? > Cl? > SO4 2? > NO3 ? > F? facies. On the other hand, majority of groundwater samples are not suitable for drinking with reference to the concentrations of TDS, TH, Mg2+ and F?, while those are not good for irrigation with respect to USSL’s and Wilcox’s diagrams, residual sodium carbonate, and magnesium hazard, but they are safe for irrigation with respect to permeability index. Thus, the study recommends suitable management measures to improve health conditions as well as to increase agricultural output.  相似文献   

3.
The hydrogeochemical study of groundwater in Dumka and Jamtara districts has been carried out to assess the major ion chemistry, hydrogeochemical processes and groundwater quality for domestic and irrigation uses. Thirty groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids (TDS), total hardness, anions (F?, Cl?, NO3 ?, HCO3 ?, SO4 2?) and cations (Ca2+, Mg2+, Na+, K+). The analytical results show the faintly alkaline nature of water and dominance of Mg2+ and Ca2+ in cationic and HCO3 ? and Cl? in anionic abundance. The concentrations of alkaline earth metals (Ca2+?+?Mg2+) exceed the alkali metals (Na+?+?K+) and HCO3 ? dominates over SO4 2??+?Cl? concentrations in the majority of the groundwater samples. Ca?CMg?CHCO3 is the dominant hydrogeochemical facies in 60?% of the groundwater samples, while 33?% samples occur as a mixed chemical character of Ca?CMg?CCl hydrogeochemical facies. The water chemistry is largely controlled by rock weathering and ion exchange processes with secondary contribution from anthropogenic sources. The inter-elemental correlations and factor and cluster analysis of hydro-geochemical database suggest combined influence of carbonate and silicate weathering on solute acquisition processes. For quality assessment, analyzed parameter values were compared with Indian and WHO water quality standards. In majority of the samples, the analyzed parameters are well within the desirable limits and water is potable for drinking purposes. Total hardness and concentrations of TDS, Cl?, NO3 ? , Ca2+ and Mg2+ exceed the desirable limits at a few sites, however, except NO3 ? all these values were below the highest permissible limits. The calculated parameters such as sodium adsorption ratio, percent sodium (%Na) and residual sodium carbonate revealed excellent to good quality of groundwater for agricultural purposes, except at few sites where salinity and magnesium hazard (MH) values exceeds the prescribed limits and demands special management.  相似文献   

4.
As one of the most arid regions in the world, the study area, Zhangye Basin is located in the middle reaches of the Heihe River, northwest China. Besides aridity, rapid social and economic development also stimulates greater demand for water, which is gradually fulfilled by groundwater extraction. In this study, the conventional hydrochemical techniques and statistical analyses were applied to examine the major ions chemistry and hydrochemical processes of groundwater in the Zhangye Basin. The results of chemical analysis indicate that no one pair of cations and anions proportions is more than 50% in the groundwater samples of the study area. High-positive correlations were obtained among the following ions: HCO3 ?–Mg2+, SO4 2?–Mg2+, SO4 2?–Na+ and Cl?–Na+. TDS depends mainly on the concentration of major ions such as HCO3 ?, SO4 2?, Cl?, Mg2+ and Na+. The hydrochemical types in the area can be divided into two major groups: the first group includes Mg2+–Na+–HCO3 ?, Mg2+–Na+–Ca2+–HCO3 ?–SO4 2? and Mg2+–Ca2+–Na+–SO4 2?–HCO3 ? types. The second group comprises Mg2+–Ca2+–SO4 2? type, Mg2+–Ca2+–SO4 2?–Cl? type and Mg2+–Na+–SO4 2?–Cl? type. The ionic ratio plot and saturation index calculation suggests that the silicate weathering, to some extent, and evaporation are dominant factors that determine the major ionic composition in the study area.  相似文献   

5.
Assessment of groundwater quality is essential to ensure sustainable use of it for drinking, agricultural, and industrial purposes. The chemical quality of groundwater of Gaya region has been studied in detail in this work to delineate the potable groundwater zones. A total of 30 groundwater samples and 2 surface water samples were collected in and around Gaya district of Bihar. The major cations follow the trend: Ca2+?>?Mg2+?>?Na+?>?K+. The domination of calcium ions in the groundwater is due to weathering of rocks. The K+ ranged between 0.2 and 47.95 ppm, suggesting its abundance the below desired limit; but some samples were found to be above permissible limit. K+ weathering of potash silicate and the use of potash fertilizer could be the source. The major anions abundance followed the order HCO 3 ? ?>?Cl??>?SO 4 2? ?>?NO 3 ? ?>?PO 4 3? . Dissolution of carbonates and reaction of silicates with carbonic acid accounts for the addition of HCO 3 ? to the groundwater and oxidation of sulphite may be the source of SO 4 2? . Principal component analysis was utilized to reflect those chemical data with the greatest correlation and seven major principal components (PCs) representing >80 % of cumulative variance were able to interpret the most information contained in the data. PC1, PC2 and PC3 reflect the hydrogeochemical processes like mineral dissolution, weathering and anthropogenic sources. PC4, PC5, PC6 and PC7 show monotonic, random and independent relationships.  相似文献   

6.
This paper provides insight into the quality of groundwater used for public water supply on the territory of Kikinda municipality (Vojvodina, Serbia) and main processes which control it. The following parameters were measured: color, turbidity, pH, KMnO4 consumption, TDS, EC, NH4 +, Cl?, NO2 ?, NO3 ?, Fe, Mn, total hardness, Ca2+, Mg2+, SO4 2+, HCO3 ?, K+, Na+, As. The correlations and ratios among parameters that define the chemical composition were determined aiming to identify main processes that control the formation of the chemical composition of the analyzed waters. Groundwater from 11 analyzed sources is Na–HCO3 type. Intense color and elevated organic matter content of these waters originate from humic substances. The importance of organic matter decay is assumed by positive correlation between organic matter content and TDS, HCO3 content. There is no evidence that groundwater chemistry is determined by the depth of captured aquifer interval. The main processes that control the chemistry of all analyzed water are cation exchange and feldspar weathering.  相似文献   

7.
Hydrogeochemistry of groundwater is important for sustainable development and effective management of the groundwater resource. Fifty-six groundwater samples were collected from shallow tube wells of the intensively cultivated southern part of district Bathinda of Punjab, India, during pre- and post-monsoon seasons. Conventional graphical plots were used to define the geochemical evaluation of aquifer system based on the ionic constituents, water types, hydrochemical facies and factors controlling groundwater quality. Negative values of chloroalkaline indices suggest the prevalence of reverse ion exchange process irrespective of the seasons. A significant effect of monsoon is observed in terms chemical facies as a considerable amount of area with temporary hardness of Ca2+–Mg2+–HCO3 ? type in the pre-monsoon switched to Ca2+–Mg2+–Cl? type (18%) followed by Na+–HCO3 ? type (14%) in the post-monsoon. Evaporation is the major geochemical process controlling the chemistry of groundwater process in pre-monsoon; however, in post-monsoon ion exchange reaction dominates over evaporation. Carbonate weathering is the major hydrogeochemical process operating in this part of the district, irrespective of the season. The abundance of Ca2+ + Mg2+ in groundwater of Bathinda can be attributed mainly to gypsum and carbonate weathering. Silicate weathering also occurs in a few samples in the post-monsoon in addition to the carbonate dissolution. Water chemistry is deteriorated by land-use activities, especially irrigation return flow and synthetic fertilisers (urea, gypsum, etc.) as indicted by concentrations of nitrate, sulphate and chlorides. Overall, results indicate that different natural hydrogeochemical processes such as simple dissolution, mixing, weathering of carbonate minerals locally known as ‘‘kankar’’ and silicate weathering are the key factors in both seasons.  相似文献   

8.
Hydogrochemical investigation of groundwater resources of Paragraph district has been carried out to assess the solute acquisition processes and water quality for domestic and irrigation uses. Fifty-five groundwater samples were collected and analyzed for pH, electrical conductivity, total dissolved solids, hardness, major anions (F?, Cl?, NO3, HCO3 ?, SO4 2?) and cations (Ca2+, Mg2+, Na+, K+). Study results reveal that groundwater of the area is alkaline in nature and HCO3 ?, Cl?, Mg2+, Na+ and Ca2+ are the major contributing ions to the dissolved solids. The hydrogeochemical data suggest that weathering of rock forming minerals along with secondary contributions from agricultural and anthropogenic sources are mainly controlling the groundwater composition of Pratapgarh district. Alkaline earth metals (Ca2++Mg2+) exceed alkalis (Na++K+) and weak acid (HCO3 ?) dominate over strong acids (Cl?+SO4 2?) in majority of the groundwater samples. Ca-Mg-HCO3 and Ca-Mg-Cl-HCO3 are the dominant hydrogeochemical facies in the groundwater of the area. The computed saturation indices demonstrate oversaturated condition with respect to dolomite and calcite and undersaturated with gypsum and fluorite. A comparison of groundwater quality parameters in relation to specified limits for drinking water shows that concentrations of TDS, F?, NO3 ? and total hardness exceed the desirable limits in many water samples. Quality assessment for irrigation uses reveal that the groundwater is good for irrigation. However, values of salinity, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), %Na and Kelley index are exceeding the prescribed limit at some sites, demanding adequate drainage and water management plan for the area.  相似文献   

9.
Hydrogeochemical studies have been carried out in a coastal region, using multivariate statistical model, for better understanding the controlling processes that influence the aquifer chemistry. Two principal components (PC1 and PC2) are extracted from the data set of chemical variables (pH, TDS, Ca2+, Mg2+, Na+, K+, HCO 3 ? , Cl?, SO 4 2? , NO 3 ? and F?), which account for 79% of the total variation in the quality of groundwater. The PC1 (salinity controlled process) includes the concentrations of TDS, Mg2+, Na+, K+, Cl?, SO 4 2? and NO 3 ? , while the PC2 (alkalinity controlled process) comprises the concentrations of pH, HCO 3 ? and F?. The spatial distribution of PC scores identifies the locations of high salinity and alkalinity processes. The first process corresponds to the influences of geogenic, anthropogenic and marine sources, and the second one to the influence of water-soil-rock interaction. Thus, the present study shows the usefulness of multivariate statistical model as an effective means of interpretation of spatial controlling processes of groundwater chemistry.  相似文献   

10.
Hydrogeochemical controlling factors for high rate of groundwater contamination in stressed aquifer of fractured, consolidated rocks belonging to semi-arid watershed are examined. The groundwater in mid-eastern part of Prakasam district confining to Musi-Gundlakamma sub-basins is heavily contaminated with nitrate and fluoride. Distinct water chemistry is noticed among each group of samples segregated based on concentration of these contaminants. The nitrate is as high as 594 mg/l and 57 % of the samples have it in toxic level as per BIS drinking water standards, so also the fluoride which has reached a maximum of 8.96 mq/l and 43 % of samples are not fit for human consumption. Nitrate contamination is high in shallow aquifers and granitic terrains, whereas fluoride is in excess concentration in deeper zones and meta-sediments among the tested wells, and 25 % of samples suffer from both NO3 ? and F? contamination. Na+ among cations and HCO3 ? among anions are the dominant species followed by Mg2+ and Cl?. The NO3 ?-rich groundwater is of Ca2+–Mg2+–HCO3 ?, Ca2+–Mg2+–Cl? and Na+–HCO3 ? type. The F?-rich groundwater is dominantly of Na+–HCO3 ? type and few are of Na+–SO4 2? type, whereas the safe waters (without any contaminants) are of Ca2+–Mg2+–HCO3 ?– and Na+–HCO3 ? types. High molecular percentage of Na+, Cl?, SO4 2? and K? in NO3 ? rich groundwater indicates simultaneous contribution of many elements through domestic sewerage and agriculture activity. It is further confirmed by analogous ratios of commonly associated ions viz NO3 ?:Cl?:SO4 2? and NO3 ?:K+:Cl? which are 22:56:22 and 42:10:48, respectively. The F? rich groundwater is unique by having higher content of Na+ (183 %) and HCO3 ? (28 %) than safe waters. The K+:F?:Ca2+ ratio of 10:5:85 and K+:F?: SO4 2? of 16:7:77 support lithological origin of F? facilitated by precipitation of CaCO3 which removes Ca2+ from solution. The high concentrations of Na+, CO3 ? and HCO3 ? in these waters act as catalyst allowing more fluorite to dissolve into the groundwater. The indices, ratios and scatter plots indicate that the NO3 ? rich groundwater has evolved through silicate weathering-anthropogenic activity-evapotranspiration processes, whereas F? rich groundwater attained its unique chemistry from mineral dissolution-water–rock interaction-ion exchange. Both the waters are subjected to external infusion of certain elements such as Na+, Cl?, NO3 ? which are further aggravated by evaporation processes leading to heavy accumulation of contaminants by raising the water density. Presence of NO3 ? rich samples within F? rich groundwater Group and vice versa authenticates the proposed evolution processes.  相似文献   

11.
A base line study involving analysis of groundwater samples from the Jhansi district were carried out to determine the major and trace element chemistry and to assess the hydrogeochemical processes and water quality for domestic and irrigation uses. Study results show that groundwater is mildly acidic to alkaline in nature and HCO3 ?, Cl?, Ca2+, Na+ and Mg2+ are the major contributing ions for the dissolved loads. The data plotted on the Gibbs and Piper diagrams reveal that the groundwater chemistry is mainly controlled by rock weathering with secondary contribution from anthropogenic sources. In a majority of the groundwater samples, alkaline earth metals exceed alkalies and weak acid dominate over strong acids. Ca–Mg–HCO3 is the dominant hydrogeochemical facies in the majority of the groundwater samples. The computed saturation indices demonstrate that groundwater is oversaturated with respect to dolomite and calcite. Kaolinite is the possible mineral that is in equilibrium with the water, implying that the groundwater chemistry favors kaolinite formation. A comparison of groundwater quality parameters in relation to specified limits for drinking water shows that the concentrations of TDS, F?, NO3 ?, total hardness and Fe are exceeding the desirable limits in many water samples. Quality assessment for irrigation uses reveal that the groundwater is of good to suitable category. Higher salinity and residual sodium carbonate values at some sites restrict the suitability of groundwater and need an adequate drainage and water management plan for the area.  相似文献   

12.
The assessment of hydrogeochemical processes that govern the water quality of inland freshwater aquifers in coastal environment, especially in Indian sub-continent, is occasionally attempted. To bridge the gap, a detail hydrochemical evaluation of groundwater occurring in coastal alluvium is attempted. Single set of high-density water sampling is done from a limited area to gain an in-depth knowledge of the processes that govern the water chemistry of the sandy aquifers. The water is of weak alkaline nature and less mineralized, EC being < 1,000 μS/cm in many samples. Major ion composition indicates that water is contaminated with excess concentration of nitrates. Ionic abundance is in the order of Cl? > Na+  > Ca2+ > HCO3 ? > SO4 2? > Mg2+  > NO3 ?. Na+ and Cl? are almost in similar proportions implying the influence of coastal climate on water quality. The water shows modest variation in their ionic assemblage among different sample points as evident from Schoeller scheme. Groundwater can be classified into three distinct facies viz. Cl?–Ca2+–Mg2+, Na+–Cl? and Ca2+–Mg2+–HCO3 ? types. The ionic assemblages, their indices, ratios and cross-plots substantiate that multiple processes were involved in the evolution of the water chemistry. Among them, silicate weathering, halite dissolution, ion exchange and base exchange played prominent role in the ion enrichment of groundwater. The aquatic chemistry is further influenced and modified by marine environment, evapotranspiration and anthropogenic inputs which is authenticated by good correlation (r 2 = 1) among the Na+–Cl?, EC–Mg2+, Na+ and Cl?. Gibbs plots established that evaporation is more responsible for contribution of minerals to the groundwater than aquifer material. Nitrate contamination can be attributed for poor sewerage disposal mechanism which is aggravated by fertilizer inputs, irrigation practices and agriculture activity. A contrasting correlation (r 2 ≥90 to <0.40) among select pairs of ions reassures dissimilar source of those ions, involvement of multiple processes and limited interaction of formation water with aquifer material.  相似文献   

13.
In this study, hydrochemical and isotope investigations were conducted in the Yanqi Basin to determine the chemical composition, and to gain insight into the groundwater recharge process in the Yanqi Basin. It mainly used hydrochemistry, environmental isotopes, and a series of comprehensive data interpretation, e.g., statistics, ionic ratios, and Piper diagram to obtain a better understanding of the functioning of the system. The following hydrochemical processes were identified as the main factors controlling the water quality of the groundwater system: weathering of silicate minerals, dissolution, ion exchange, and to a lesser extent, evaporation, which seemed to be more pronounced down gradient of the flow system. As groundwater flows from the recharge to discharge areas, chemical patterns evolve in the order of Ca2+–HCO3 ?, Ca2+/Mg2+–HCO3 ? to Ca2+–Mg2+–Cl?–SO4 2?, Na+–K+–Cl?–SO4 2? and Na+–Cl? according to lithology. The environmental isotope (δ 18O, δ 2H, 3H) measurements further revealed that precipitation was the main recharge source for the groundwater system; some local values indicated high levels of evaporation. Tritium and CFC analysis were used to estimate the ages of the different groundwater; the tritium values of the groundwater samples varied from 2.82 to 29.7 TU. The age of the groundwater at depths of <120 m is about 30–50 years. CFC values obtained for six samples to determine groundwater age; the age of the groundwater is about 20–50 years.  相似文献   

14.
The study of groundwater hydrogeochemistry of a hard rock aquifer system in Thoothukudi district has resulted in a large geochemical data set. A total of 100 water samples representing various lithologies like Hornblende Biotite Gneiss, Alluvium Marine, alluvium Fluvial, Quartzite, Charnockite, Granite and Sandstone were collected for two different seasons and analyzed for major ions like Ca2+, Mg2+, Na+, K+, HCO3 ?, Cl?, SO4 2?, NO3 ?, PO4 ?, F? and H4SiO4. Statistical analysis of the data has been attempted to unravel the hidden relationship between ions. Correlation analyses and factor analyses were applied to classify the groundwater samples and to identify the geochemical processes controlling groundwater geochemistry. Factor analysis indicates that sea water intrusion followed by leaching of secondary salts, weathering and anthropogenic impacts are the dominant factors controlling hydrogeochemistry of groundwater in the study area. Factor score overlay indicate major active hydrogeochemical regimes are spread throughout the Eastern, Northwestern and Southeastern parts of the study area. The dominant ions controlling the groundwater chemistry irrespective of season are Cl?, Na+, Mg2+, Ca2+, SO4 2?, K+ and NO3 ?. An attempt has also been made to note the seasonal variation of the factor representations in the study area. This study also illustrates the usefulness of statistical analysis to improve the understanding of groundwater systems and estimates of the extent of salinity/salt water intrusion.  相似文献   

15.
This study applied a comprehensive quantitative approach including statistical, principal component and gray relation analyses to assess the groundwater chemistry based on monitored data from 840 samples collected from the lower reaches of Tarim River from 2000 to 2009. The main findings were: (1) there were six types of groundwater chemistry in the lower reaches of Tarim River where Cl·SO4–Na·Mg was the dominant type accounting for 73.57% in all samples. There were linear relationships among chemical parameters, where TDS had significant multiple correlations with Na+, K+, Mg2+, Ca2+ and Cl−, respectively. (2) Three principal components (PC1, PC2 and PC3) were extracted. They included comprehensive measurements for salinization, alkalinity and pH, respectively. Most parameters showed decreasing trends during the period of 2000–2009, as well as the scores on PC1, because the concentrations of various chemical substances were diluted due to the uplift of the groundwater table in the lower reaches and the implementation of the ecological water delivery project in 2000. (3) HCO3 − was the most sensitive chemical parameter affected by the groundwater table followed by TA, Mg2+, TH, SO42−, K+, TDS and TS. PC2 was the most sensitive principal component to the change of the groundwater table followed by PC1 and PC3.  相似文献   

16.
Hydrochemical investigations were carried out in Damagh area, Hamadan, western Iran, to assess chemical composition of groundwater. Forty representative groundwater samples were collected from different wells to monitor the water chemistry of various ions. Chemical analysis of the groundwater showed that the mean concentration of the cations is in the order Na+ > Ca2+ > Mg2+ > K+, while that for anions was HCO3− > Cl− > SO42 − > NO3−. All of the investigated groundwaters present two different chemical facies (Ca–HCO3 and Na–HCO3) which is in relation with their interaction with the geological formations of the basin, cation exchange between groundwater and clay minerals and anthropogenic activities. The principal component analysis (PCA) performed on groundwater identified three principal components controlling their variability in groundwater. Electrical conductivity, Mg2+, Na+, SO42−, and Cl− content were associated in the same component (PC1) (salinity), determined principally by anthropogenic activities. The pH, CO32 −, HCO3−, and Ca2+ (PC2) content were related to the geogenic factor. Finally, the NO3−, Cl− and K+ (PC3) were controlled by anthropogenic activity as a consequence of inorganic fertilizers.  相似文献   

17.
Groundwater of an aquifer located in the vicinity of a large coal washery near Zarand City, Iran consists of two hydrochemically differing facies, which have been informally designated as groundwater (A) and groundwater (B). Groundwater (A) is native, brackish in composition and is characterized by Na+ > Mg2+ > Ca2+ > K+ and SO4 2? > HCO3 ? > Cl? > NO3 ?. Spearman’s rank correlation coefficient matrices, factor analysis data, and values of chloro-alkaline indices, C ratio and Na+/Cl? molar ratio indicate that in the groundwater (A), the ionic load of Ca2+, Mg2+, Na+, K+, SO4 2? and HCO3 ? is derived essentially from weathering of both carbonates and aluminosilicates and direct cation and reverse cation–anion exchange reactions. Groundwater (B) is the polluted variant of the groundwater (A), brackish to saline in composition, and unlike the groundwater (A), consists of HCO3 ? as the dominant anion. In comparison with the groundwater (A), the groundwater (B) contains higher concentrations of all ions, and its average ionic load (av. = 59.74 me/L) is 1.43 times higher than that of the groundwater (A) (av. = 41.54 me/L). Additional concentrations of Ca2+, Mg2+, K+, SO4 2?, Cl? and HCO3 ? in the groundwater (B) are provided mainly by downward infiltrating water from the coal washery tailings pond and reverse cation–anion exchange reaction between tailings pond water and exchanger of the aquifer matrix during non-conservative mixing process of groundwater (A) and tailings pond water. Certain additional concentrations of Na+, K+ and NO3 ? in the groundwater (B) are provided by other anthropogenic sources. Quality wise, both groundwaters are marginally suitable for cultivation of salt-tolerant crops only.  相似文献   

18.
  相似文献   

19.
The hydrogeochemical study of surface and subsurface water of Mahi River basin was undertaken to assess the major ion chemistry, solute acquisition processes and water quality in relation to domestic and irrigation uses. The analytical results show the mildly acidic to alkaline nature of water and dominance of Na+ and Ca2+ in cationic and HCO3 − and Cl− in anionic composition. In general, alkaline-earth elements (Ca2+ + Mg2+) exceed alkalis (Na+ + K+) and weak acids (HCO3 −) dominate over strong acids (SO4 2+ + Cl−) in majority of the surface and groundwater samples. Ca2+–Mg2+–HCO3 − is the dominant hydrochemical facies both in surface and groundwater of the area. The weathering of rock-forming minerals mainly controlled the solute acquisition process with secondary contribution from marine and anthropogenic sources. The higher concentration of sodium and dissolved silica, high equivalent ratios of (Na+ + K+/TZ+), (Na+ + K+/Cl−) and low ratio of (Ca2+ + Mg2+)/(Na+ + K+) suggest that the chemical composition of the water is largely controlled by silicate weathering with limited contribution from carbonate weathering and marine and anthropogenic sources. Kaolinite is the possible mineral that is in equilibrium with the water, implying that the chemistry of river water favors kaolinite formation. Assessment of water samples for drinking purposes suggests that the majority of the water samples are suitable for drinking. At some sites concentrations of TDS, TH, F−, NO3 − and Fe are exceeding the desirable limit of drinking. However, these parameters are well within the maximum permissible limit except for some cases. To assess the suitability for irrigation, parameters like SAR, RSC and %Na were calculated. In general, both surface and groundwater is of good to suitable category for irrigation uses except at some sites where high values of salinity, %Na and RSC restrict its uses.  相似文献   

20.
Detailed hydrogeochemical investigation has provided new information concerning the major factors and mechanisms controlling the groundwater chemistry of Chougafiya basin. The hydrogeochemical characteristics of groundwaters comprise three main types: Cl–SO4–Ca, Cl–SO4–Na and Cl–Na. Hydrochemical characteristics based on the bivariate diagrams of major (Cl?, SO4 2?, NO3 ?, HCO3 ?, Na+, Mg2+, K+ and Ca2+) and some trace (Br? and Sr2+) ions, mineral saturation indices and hierarchical cluster analysis indicate different origins of groundwater mineralization. The water–rock interaction (dissolution of evaporitic minerals), followed by cation exchange reactions with clay minerals, constitute the main processes that control groundwater salinization. However, the chemical composition of brackish groundwater in the central and southern parts of the study area is influenced by a mixing process with Sabkhas salt groundwater. The mixing proportions inferred from chloride mass balance prove that the contribution of Sabkhas groundwater to Quaternary aquifer ranges between 2.7 and 9.1 %. These intrusion rates reflect the progress of the saltwater–freshwater interface, which is mainly controlled by the piezometric level variation and the distance to the Sabkhas.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号