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1.
Fluoride (F?) is the most important element for human health. Hydrogeochemical survey was conducted to probe into the controlling factors of F? in the groundwater of a semi-arid part of South India. The study area comprises of F?-bearing minerals (hornblende, biotite, and apatite) in the Precambrian rocks, sandstones in the Upper Gondwana rocks, and clays in the Quaternary formations. Forty-seven percent of the total groundwater samples have the higher F? content than its permissible limit of 1.50 mg/L prescribed for drinking purpose. The chemical data of the groundwater is analyzed to assess the geochemical processes dominating the F?-bearing groundwater, using Piper and Gibbs diagrams, correlations, saturation indices, ionic ratios, and multivariate analysis. Piper diagram shows that the groundwater quality is characterized by Na+-HCO\( {}_3^{-} \) and Na+-Cl?types, while the Gibbs diagrams suggest that the groundwater chemistry is mainly controlled by water-rock interactions and is subsequently modified by human activities. The F? groundwater is positively correlated with pH, total dissolved solids, Mg2+, Na+, K+, HCO\( {}_3^{-} \), Cl?, SO\( {}_4^{2-} \), and NO\( {}_3^{-} \) and negatively with Ca2+, representing the influences of geogenic and anthropogenic origins on the groundwater system. Geochemical ratios and saturation indices indicate that the processes of mineral dissolution, ion exchange, and evaporation mainly govern the high F? groundwater, while the chemical fertilizers cause for the enrichment of F?in the groundwater. Cluster and principal component analyses further support the above findings.  相似文献   

2.
A survey on quality of groundwater was carried out for assessing the geochemical characteristics and controlling factors of chemical composition of groundwater in a part of Guntur district, Andhra Pradesh, India, where the area is underlain by Peninsular Gneissic Complex. The results of the groundwater chemistry show a variation in pH, EC, TDS, Ca2+, Mg2+, Na+, K+, HCO3 ?, Cl?, SO4 2?, NO3 ? and F?. The chemical composition of groundwater is mainly characterized by Na+?HCO3 ? facies. Hydrogeochemical type transits from Na+–Cl?–HCO3 ? to Na+–HCO3 ?–Cl? along the flow path. Graphical and binary diagrams, correlation coefficients and saturation indices clearly explain that the chemical composition of groundwater is mainly controlled by geogenic processes (rock weathering, mineral dissolution, ion exchange and evaporation) and anthropogenic sources (irrigation return flow, wastewater, agrochemicals and constructional activities). The principal component (PC) analysis transforms the chemical variables into four PCs, which account for 87% of the total variance of the groundwater chemistry. The PC I has high positive loadings of pH, HCO3 ?, NO3 ?, K+, Mg2+ and F?, attributing to mineral weathering and dissolution, and agrochemicals (nitrogen, phosphate and potash fertilizers). The PC II loadings are highly positive for Na+, TDS, Cl? and F?, representing the rock weathering, mineral dissolution, ion exchange, evaporation, irrigation return flow and phosphate fertilizers. The PC III shows high loading of Ca2+, which is caused by mineral weathering and dissolution, and constructional activities. The PC IV has high positive loading of Mg2+ and SO4 2?, measuring the mineral weathering and dissolution, and soil amendments. The spatial distribution of PC scores explains that the geogenic processes are the primary contributors and man-made activities are the secondary factors responsible for modifications of groundwater chemistry. Further, geochemical modeling of groundwater also clearly confirms the water–rock interactions with respect to the phases of calcite, dolomite, fluorite, halite, gypsum, K-feldspar, albite and CO2, which are the prime factors controlling the chemistry of groundwater, while the rate of reaction and intensity are influenced by climate and anthropogenic activities. The study helps as baseline information to assess the sources of factors controlling the chemical composition of groundwater and also in enhancing the groundwater quality management.  相似文献   

3.
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   

4.
The main aims of the present study are to identify the major factors affecting hydrogeochemistry of groundwater resources in the Marand plain, NW Iran and to evaluate the potential sources of major and trace elements using multivariate statistical analysis such as hierarchical clustering analysis (HCA) and factor analysis (FA). To achieve these goals, groundwater samples were collected in three sampling periods in September 2013, May 2014 and September 2014 and analyzed with regard to ions (e.g., Ca2+, Mg2+, Na+ and K+, HCO3 ?, SO4 2?, Cl?, F? and NO3 ?) and trace metals (e.g., Cr, Pb, Cd, Mn, Fe, Al and As). The piper diagrams show that the majority of samples belong to Na–Cl water type and are followed by Ca–HCO3 and mixed Ca–Na–HCO3. Cross-plots show that weathering and dissolution of different rocks and minerals, ion exchange, reverse ion exchange and anthropogenic activities, especially agricultural activities, influence the hydrogeochemistry of the study area. The results of the FA demonstrate that 6 factors with 81.7% of total variance are effective in the overall hydrogeochemistry, which are attributed to geogenic and anthropogenic impacts. The HCA categorizes the samples into two clusters. Samples of cluster C1, which appear to have higher values of some trace metals like Pb and As, are spatially located at the eastern and central parts of the plain, while samples of cluster C2, which express the salinization of the groundwater, are situated mainly westward with few local exceptions.  相似文献   

5.
The hydrogeochemistry of groundwater in rural parts of Birbhum district, West Bengal, India, has been studied to understand the contaminants and prime processes involved in their enrichment with a focus on F? concentration. The lithological units consist of Quaternary alluviums with underlying Rajmahal basaltic rocks of Middle Jurassic age. Groundwater occurs in the alluviums, weathered residuum and fracture zone of Rajmahal rocks. Studies show elevated concentration of Cl?, SiO2, Fe and F?; excess Cl? is attributed to anthropogenic inputs, SiO2 is ascribed to high degree of weathering of silica rich host rocks, and high Fe is due to the interaction of water with Fe-rich sediments under reducing condition. The F? concentration is found high (>1.20 mg/L) mainly in water from Rajmahal rocks revealing a lithological control on F? enrichment. The weathering of silicates and ion exchange are the leading controlling processes for major ions in groundwater. The F? enrichment is due to the dissolution of F?-bearing minerals and perhaps also through anion exchange (OH? for F?) on clay minerals at high alkaline conditions; precipitation of CaCO3 favours CaF2 dissolution leading to elevated F? concentration. CaHCO3, the dominant water type, contains low F? while NaHCO3 and NaCl types exhibit high F? concentrations. Among the three spatial associations, Cluster-1 and Cluster-2 are CaHCO3 type; Cluster-3 shows NaHCO3 and NaCl waters with low Ca2+ and Mg2+ and high Na+ contents. Cluster-1 and Cluster-2 waters are, in general, drinkable barring the elevated Fe content, while Cluster-3 water is unsafe for drinking due to the high F? concentration.  相似文献   

6.
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   

7.
Groundwater is a precious resource for humankind not only in Nepal but also across the globe due to its diverse functions. A total of 48 groundwater samples were collected from three villages of Nawalparasi district, Nepal, during pre-monsoon and monsoon to estimate the overall groundwater quality and to identify the sources of contamination with emphasis on arsenic (As). The average concentrations of all tested groundwater quality parameters (temp., pH, EC, ORP, Ca2+, Mg2+, Na+, K+, Cl?, F?,SO4 2?, PO4 3?, HCO3 ?, NO3 ?, Cu, Ni, Mn, Cd, Pb, Fe, Zn, Cr, and As) were well within permissible limits of WHO for drinking water, except for Ni, Cd, Pb, Cr, and As. Concentration of As ranged from 60 to 3,100 μg L?1 and 155 to 1,338 μg L?1 in pre-monsoon and monsoon, respectively. The Piper diagram of the groundwater chemistry showed groundwater of Nawalparasi belongs to Ca–Mg–HCO3 and Mg–HCO3 water type with HCO3 ? as dominant ions. As content in the study area was negatively correlated with Fe in pre-monsoon, while it was positively correlated in monsoon. Furthermore, As was negatively correlated with oxidation reduction potential suggesting reducing condition of groundwater. Principal component analysis revealed seven major factors that explained 81.996 and 83.763 % of total variance in water quality in pre-monsoon and monsoon, respectively. The variance of water quality was related mainly with the degree of water–rock interaction, mineralization, and anthropogenic inputs.  相似文献   

8.
The accurate information through water quality analysis, scientific study on F ? distribution in groundwater and geochemical knowledge with spatial information on geology and climate are necessary to understand the source/cause, type and level of F ? contamination. The Dindigul district is a hard-rock terrain and marked as one of the fluoride-rich area in Tamilnadu due to occurrence of various rock types including fluoride-bearing minerals. The F ? content of groundwater can thus originate from the dissolution of fluoride-bearing minerals in the bed rock. Eighty-six representative groundwater samples from Dindigul district was collected during two different seasons. Samples were analysed for F ?, other major cations and anions. The study area is chiefly composed of hornblende biotite gneiss and charnockite, apart from this untreated tannery effluents also let from many places in the study area. Geographical Information System technique was adopted to study the sources of F ?, and it was found that F ? in the study is mainly attributed to geogenic source.  相似文献   

9.
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   

10.
Fluoride (F?) has significant impacts on human health. High fluoride groundwater (up to 1.90 mg/L) has been found in upper confined aquifer underlying the first terrace of Weihe River during a hydrogeological investigation for water supply in 2005. To reveal the occurrence and hydrogeochemistry of high F? groundwater, hydrogeochemical tools such as saturation index, ionic ratios and correlation analysis were used in this study. The study shows that the concentrations of most physiochemical parameters from phreatic water, influenced by intensive evaporation and anthropogenic activities such as unregulated sewage and excreta disposal and agricultural practices in the area, are higher than those of confined water. The F? concentration in phreatic water is within the acceptable limits set by China and the World Health Organization (WHO), while that of upper confined water shows a decreasing trend northwestward as the Weihe River approaches, with F? concentration in the first terrace beyond the national and the WHO standards. High F? groundwater is observed in alkaline environment associated with high Na+, pH, HCO3 ? and low Ca2+ and Mg2+. The enrichment of F? is controlled by geologic and hydrogeological conditions, fluorine-bearing minerals presented in alluvial formations and their dissolution/precipitation under the alkaline environment along groundwater flow. Ion exchange, human activities and the mixing of different recharge waters may influence the enrichment of F? as well.  相似文献   

11.
The aim of the present study is to identify the geochemical processes responsible for higher fluoride (F–) content in the groundwater of the Yellareddigudem watershed located in Nalgonda district, Andhra Pradesh. The basement rocks in the study area comprise mainly of granites (pink and grey varieties), which contain F-bearing minerals (fluorite, biotite and hornblende). The results of the study area suggest that the groundwater is characterized by Na+: HCO facies. The F– content varies from 0.42 to 7.50 mg/L. In about 68% of the collected groundwater samples, the concentration of F– exceeds the national drinking water quality limit of 1.5 mg/L. The weathering of the granitic rocks causes the release of Na+ and HCO ions, which increase the solubility of ions. Ion exchange between Na+ and Ca2+, and precipitation of CaCO3 reduce the activity of Ca2+. This favours dissolution of CaF2 from the F-bearing minerals present in the host rocks, leading to a higher concentration of F– in the groundwater. The study further suggests that the spatial variation in the F– content appears to be caused by difference in the relative occurrence of F-bearing minerals, the degree of rockweathering and fracturing, the residence time of water in the aquifer materials and the associated geochemical processes. The study emphasizes the need for appropriate management measures to mitigate the effect of higher F groundwater on human health.  相似文献   

12.
The Louros Basin hosts one of the most important karst systems of Epirus Prefecture (Greece) and plays a key role in supplying three counties with drinking water. Aiming to investigate the origin of groundwater and its flow patterns, a multi-tracer approach was used to describe and evaluate the hydrogeology of the system. Therefore, 271 surface water and groundwater samples were collected and analyzed for physicochemical parameters, major ions, and trace and rare earth elements, as well as stable isotopes (δ18O and δ2H). These data provided meaningful tracing of the water origin, water–rock interaction processes, and relationships among the aquifers. In particular, the elaboration of the major ions supported by the distribution of rare earth elements indicated that there are three aquifers located at different levels hosted in the Senonian and Pantokrator limestone formations. These aquifers are hydraulically interconnected by a cascade and constitute the Louros karst system which is drained by the homonymous river. Hydrochemical and isotopic data revealed that the Louros karst system is isolated from the adjacent northern Ioannina Basin and it is being recharged by precipitation. Higher groundwater salinity, where present, is mainly associated with increased water–rock interaction due to longer and deeper hydrologic flow, favoring the dissolution of evaporitic, carbonate and phosphate minerals.  相似文献   

13.
A total of 194 groundwater samples were collected from wells in hard rock aquifers of the Medak district, South India, to assess the distribution of fluoride in groundwater and to determine whether this chemical constituent was likely to be causing adverse health effects on groundwater user in the region. The study revealed that the fluoride concentration in groundwater ranged between 0.2 and 7.4 mg/L with an average concentration of 2.7 mg/L. About 57% of groundwater tested has fluoride concentrations more than the maximum permissible limit of 1.5 mg/L. The highest concentrations of fluoride were measured in groundwater in the north-eastern part of the Medak region especially in the Siddipeta, Chinnakodur, Nanganoor and Dubhaka regions. The areas are underlain by granites which contain fluoride-bearing minerals like apatite and biotite. Due to water–rock interactions, the fluoride has become enriched in groundwater due to the weathering and leaching of fluoride-bearing minerals. The pH and bicarbonate concentrations of the groundwater are varied from 6.6 to 8.8 and 18 to 527 mg/L, respectively. High fluoride concentration in the groundwater of the study area is observed when pH and the bicarbonate concentration are high. Data plotted in Gibbs diagram show that all groundwater samples fall under rock weathering dominance group with a trend towards the evaporation dominance category. An assessment of the chemical composition of groundwater reveals that most of the groundwater samples have compositions of Ca2+–Mg2+–Cl? > Ca2+–Na+–HCO3 ? > Ca2+–HCO3 ? > Na+–HCO3 ?. This suggests that the characteristics of the groundwater flow regime, long residence time and the extent of groundwater interaction with rocks are the major factors that influence the concentration of fluoride. It is advised not to utilize the groundwater for drinking purpose in the areas delineated, and they should depend on alternate safe source.  相似文献   

14.
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15.
Fluoride (F?) is an indispensable element for the human’s skeletal and dental health at prescribed levels and becomes lethal at higher levels. Spatial–temporal variability of F? and its geochemical control/association with other dissolved ions in groundwater in the Dindigul district of Tamilnadu (India) were conducted to describe the geochemical dynamics of F– in response to seasonal variability. High concentrations of fluoride (≥1.5 mg L?1) were observed in the northern region of the district. High levels of F? were observed in non-monsoon periods and low levels in monsoon, because of dilution by precipitation. Bicarbonate was well correlated with F? which explains that both ions were derived from the weathering. While F? has a very weak correlation with silica, this implies that the silicate weathering does not supply F? to the groundwater system. The F? pollution in Dindigul groundwaters is mainly driven by two factors: (1) the geogenic weathering inputs, the geology of this area mainly comprises fluoride bearing minerals (e.g. hornblende biotite gneiss and charnockite); (2) the anthropogenic inputs (agri-fertilizers and tannery waste). Further, F? in the study area is mainly attributed to geogenic sources during pre and postmonsoons and anthropogenic sources in monsoon periods.  相似文献   

16.
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   

17.
Presence of fluoride in groundwater is a public health problem in the so-called endemic fluorosis belt of the central Iran, where the groundwater is the major source of drinking water in most urban and rural areas. Therefore, an attempt has been made to determine the hydrogeochemical factors controlling fluoride enrichment in the groundwater resources at this belt. Fluoride concentrations ranged from 0.20 to 1.99 mg/L (1.02 ± 0.47) in groundwater samples. The presence of different F-bearing minerals and also clay minerals in the soils and aquifer materials was confirmed using XRD analysis. To identify probable sources of dissolved F? and investigate groundwater quality, multivariate statistical analyses were carried out. Geochemical modeling indicated that all samples were undersaturated with respect to fluorite, halite, gypsum and anhydrite and mostly oversaturated with respect to calcite and dolomite. Contrary to most high-fluoride regions in the World, the high F? content was dominated by Na–Cl- and Ca–SO4-type groundwater in the study area. Besides, fluoride showed negative relationship with pH and HCO3 ? in groundwater. In order to assess the bioavailability of fluoride in soils, a two-step chemical fractionation method was applied. The results showed that fluoride in soils mostly accompanied with the residual and water-soluble fractions and was poorly associated with soil’s bonding sites. Calculated aqueous migration coefficient demonstrated that fluoride in the studied soils was mobile to easily leachable to the groundwater. Finally, the results demonstrated that combination of water–rock interaction and influence of clay minerals is geochemical mechanism responsible for controlling fluoride enrichment in groundwater.  相似文献   

18.
There are 59 springs at the Gevas–Gurp?nar–Güzelsu basins, 38 of these springs emerge from the fractured karst aquifers (recrystallized limestone and travertine) and 21 emerge from the Yuksekova ophiolites, K?rkgeçit formation and alluvium. The groundwater samples collected from 38 out of the total of 59 springs, two streams, one lake and 12 wells were analyzed physico-chemically in the year 2002. EC and TDS values of groundwater increased from the marble (high altitude) to the ophiolites and alluvium (toward Lake Van) as a result of carbonate dissolution and connate seawater. Five chemical types of groundwater are identified: Ca–Mg–HCO3, Mg–Ca–HCO3, Mg–Na–HCO3, Na–Ca–HCO3 and Mg–Ca–Na–HCO3. The calculations and hydrochemical interpretations show that the high concentrations of Ca2+, Mg2+ and HCO3 ? as predominant ions in the waters are mainly attributed to carbonate rocks and high pCO2 in soil. Most of the karst springs are oversaturated in calcite, aragonite and dolomite and undersaturated in gypsum, halite and anhydrite. The water–rock interaction processes that singly or in combination influence the chemical composition of each water type include dissolution of carbonate (calcite and dolomite), calcite precipitation, cation exchange and freshening of connate seawater. These processes contribute considerably to the concentration of major ions in the groundwater. Stable isotope contents of the groundwater suggest mainly direct integrative recharge.  相似文献   

19.
The Narava basin in Visakhapatnam district situated on the east coast is a productive agricultural area, and is also one of the fastest growing urban areas in India. The agricultural and urban-industrialization activities have a lot of impact on this coastal aquifer water quality. The hydrochemistry of the groundwater was analyzed in the basin area with reference to drinking and agricultural purposes. The area is underlain by Precambrian rocks like khondalites, charnockites and migmatites. The water samples were collected from shallow wells for the year 2008. Physical and chemical parameters of groundwater such as pH, total alkalinity (TA), electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), Ca2+, Mg2+, Na+, K+, HCO3 ?, Cl?, SO4 2?, NO3 ?, F? were determined. The analytical results revealed that the most of the groundwater found to be in polluted category. Geographical information system (GIS) was utilized to generate different spatial distribution maps of various chemical constituents in the study area. The analytical data were used to compute certain parameters such as salinity hazard, percent sodium (Na%), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), permeability index (PI), Kelley??s ratio (KR) and corrosivity ratio (CR) to determine the quality of water for agricultural purposes. The abundance of the major ions in the basin area was found to be in the following sequence: Na+?>?Ca2+?>?Mg2+?>?K+:Cl??>?HCO3 ??>?SO4 2??>?NO3 ??>?F?. According to Gibbs?? diagram most of the samples fall under rock dominance. As per Wilcox and USSL classification most of the groundwater samples are suitable for irrigation except few samples which are unsuitable due to the presence of high salinity and high sodium hazard. From the obtained data, it can be concluded that the water quality profile was good and useful for normal irrigation agriculture.  相似文献   

20.
The present paper deals with major and trace elements geochemistry of the groundwater from Nalgonda district, Telangana. The study area is very important in terms of anthropogenic activity like rapid industrial, urban development, pesticides, pharmaceutical, granite polishing and agro based industries. Inductively coupled plasma mass spectrometer (ICPMS) was employed to determine the concentration of trace elements in collected groundwater samples (bore well). These probe elements were further categorized as toxic elements (Pb, As, Cd, and V), alkaline earths (Sr and Ba), alkali metals (Li, Rb), transition metals (Cr, Mo and Ni), metallic elements (Cu, Fe, Zn, Al, Co), and other non-metallic elements (Se and Si). The groundwater quality was examined in perspective of Indian as well as World Health Organization drinking water standards. Based on the analytical results, groundwater in the study area is found to be slightly alkaline in nature and very hard, the average abundance of the major cations and anions is in the order of Ca+<Na+<Mg+<K+ and Cl-<HCO3 ?<CO3 ?<SO4 ?<NO3 ?<F– respectively. The dominant hydro chemical facies of groundwater is Na+ - HCO 3 – – Cl– and Na+ - Cl– – HCO– 3 types.The results of trace elements shows that concentration of Pb, As, Cd, V in collected samples exceeding the desirable limits, and in the case of alkaline, alkali, transition, non-metallic elements, seventy per cent of the samples crossed the desirable limits, but all metallic elements viz. Cu, Fe, Zn, Al, Co is within the limits as per Indian as well as World Health Organizations drinking water standards. Factor analysis results shows that seven factors emerged as a significant contributor to the groundwater contamination is about 65.32 per cent. The spatial variation maps decipher trace elemental concentrations both geogenic and anthropogenic origin, by three zones i.e. ‘low’, ‘moderate’ and ‘high’ of the study area based on environment using Arc-GIS. High concentrations of trace elements are indicative of phenomenal rise in chemical composition and likely to have its origin from silicate weathering reactions and dissolution/precipitation processes supported by rainfall and anthropogenic activities, indiscriminate use of fertilizers/pesticides, and disposal of waste and sewage, release of reactive pollutants into the atmosphere by industries. Hence, this work is of immense societal benefit in terms of prevailing human health hazards in the study area with a direct relevance to such industrially populated regions elsewhere.  相似文献   

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