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1.
Hydrogeochemical investigation of groundwater has been carried out in the coastal aquifers of southern Tamil Nadu, India. Seventy-nine dug well samples were collected and analyzed for various physicochemical parameters. The result of the geochemical analysis indicates the groundwater in the study area is slightly alkaline with moderate saline water. The cation and anion concentrations confirm most of the groundwater samples belong to the order of Na+ > Mg2+ > Ca2+ > K+ and Cl? > SO4 2? > HCO3 ?. Thereby three major hydrochemical facies (Ca–Cl, mixed Ca–Mg–Cl and Na–Cl) were identified. Based on the US Salinity diagram, majority of the samples fall under medium to very high salinity with low to high sodium hazard. The cross plot of Ca2+ + Mg2+ versus chloride shows 61 % of the samples fall under saline water category. Higher EC, TDS and Cl concentrations were observed from Tiruchendur to Koodankulam coastal zone. It indicates that these regions are significantly affected by saltwater contamination due to seawater intrusion, saltpan deposits, and beach placer mining activities.  相似文献   

2.
The present work was carried out in Nalbari district of Assam (India) with an objective to assess the quality of groundwater and to check its suitability for drinking and irrigation purposes. Groundwater samples were collected from 50 different locations during pre- and post-monsoon seasons of 2016. Results of chemical analysis revealed that mean concentration of cations varied in the order Ca2+?>?Na+?>?Mg2+?>?K+, while for anions the order was HCO3 ??>?Cl??>?SO42??>?NO32??>?F? during both pre- and post-monsoon seasons. The suitability of groundwater samples for drinking purpose was assessed by comparing the results of physico-chemical analysis of groundwater with Indian Standards. Further, its suitability for irrigation purpose was assessed by evaluating several parameters like sodium adsorption ratio (SAR), sodium percentage (Na%), magnesium ratio, Kelly’s ratio and residual sodium carbonate (RSC). The SAR values obtained for all the samples were plotted against EC values in the US Salinity Laboratory diagram, and it was revealed that the most of the samples fall under water type C2-S1 indicating medium salinity and low SAR. Further, it was found that the majority of the samples belong to Ca–Mg–HCO3 hydrochemical facies followed by Ca–Mg–Cl–SO4, whereas only a few samples belong to Na–K–HCO3 hydrochemical facies.  相似文献   

3.
The Varahi Irrigation project site is located at 13°39′15″N (latitude) and 74°57′E (longitude) in Hole Shankaranarayana village, approximately 6 km from Siddapura, Kundapura taluk, Udupi district. A total of 59 groundwater samples were collected from dug and tube wells in November 2008 to evaluate hydrochemistry and suitability for drinking and irrigation purposes. The physico-chemical parameters estimated include pH, electrical conductivity (EC), total dissolved solids (TDS), redox potential (Eh), total hardness (TH), total alkalinity (TA), temperature, major cations and anions, besides irrigation quality parameters like boron, sodium absorption ratio (SAR), % Na, residual sodium carbonate (RSC), residual sodium bicarbonate (RSBC), chlorinity index, soluble sodium percentage (SSP), exchangeable sodium ratio (ESR), non-carbonate hardness, potential salinity (PS), permeability index (PI), Kelly index (KI), magnesium hazard (MH), magnesium ratio (MR), index of base exchange. Chloride, sulphate and bicarbonate concentrations classified the groundwater samples into normal chloride, normal sulphate and normal bicarbonate water types, respectively. The Salinity (Class I; 98.3%), Chlorinity (Class I; 100%) and Sodicity (Class 0; 96.6%) indices suggest the suitability of groundwater for irrigation. The Wilcox diagram illustrates that 96.6% of the samples belongs to excellent to good category, while the US Salinity Laboratory (USSL) diagram indicates the low salinity/low sodium content in 86.44% of samples (C1S1). Positive index of base exchange in majority of the samples (91.52%) indicates direct base exchange reaction or chloro-alkaline equilibrium in the study area. The positive value of RSC in majority of samples signifying higher concentrations of HCO3 over alkaline earths indicates that groundwater are base exchange-softened water as there is an exchange of alkaline earths for Na+ ions. Majority of water samples fall in the precipitation dominance field based on Gibbs’ ratio.  相似文献   

4.
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   

5.
Groundwater samples from 62 locations have been collected from Tirupur region viz. Avinashi, Tirupur and Palladam taluks of Coimbatore District. The extensive agricultural industrial activities and urbanization resulted in the contamination of the aquifer. To study the contamination of groundwater, water samples were collected in an area of 180 km2 and analysed for major cations and anions. Most of the locations are contaminated by higher concentration of EC, TDS, K and NO3. Major hydro chemical facies were identified using Piper trilinear diagram. Based on US salinity diagram, most of the samples fall in the field of C3S1, indicating high salinity and low sodium water, which can be used for almost all types of soil with little danger of exchangeable sodium. Majority of the samples are not suitable for domestic purposes and far from drinking water standards. However, PI values indicates that groundwater is suitable for irrigation.  相似文献   

6.
Hydrogeochemical characteristics of groundwater and its suitability for domestic, irrigation, and industrial purposes were evaluated in Nanded Tehsil. A total of 50 representative groundwater samples were collected from dug/bore wells during post monsoon season 2012 and analyzed for major cations and anions. The order of dominance of cation and anions were Na > Ca > Mg > K and HCO3 > Cl > CO3 > SO4 > NO3, respectively. The rock weathering and evaporation processes are dominant in controlling the groundwater quality in the study area. Electrical conductivity (EC) and total dissolved solid (TDS) show high positive correlation with total Hardness (TH), Ca, Na, and Cl. As per the WHO and BIS standards for domestic water purposes, TDS, TH, Ca, Mg, Na, and Cl exceed the safe limits in 16, 22, 6, 18, 12, and 15 %, respectively; therefore, majority of samples show that the groundwater is suitable for drinking. The spatial distribution maps of physicochemical parameters were prepared in ArcGIS. The suitability of groundwater for agriculture purpose was evaluated from EC, TDS, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), and %Na which ranges from excellent to unsuitable, so majority of the groundwater samples are suitable for irrigation. The U.S. Salinity Laboratory (USSL) diagram shows that most of the groundwater samples are characterized as in high salinity-low sodium hazard type water (C3-S1). All the groundwater samples are suitable for industrial use except sample numbers 44 and 48. Thus, most of the groundwater samples from this study confirm the beneficial use of aquifers in the area for domestic, agricultural, and irrigation purposes. However, sample numbers 44 and 48 identify the two aquifers in the study area which are problematic and need particular remedial measures if they are to have beneficial use.  相似文献   

7.
A hydrogeochemical investigation was conducted in a coastal region of Cuddalore district to identify the influence of saltwater intrusion and suitability of groundwater for domestic and agricultural purposes. The geology of the study area comprises of sandstone, clay, alluvium, and laterite soils of Tertiary and Quaternary age. A total of 18 groundwater samples were analyzed for 14 different water quality parameters and the result indicates higher concentrations of ions like Cl (3,509 mg/l), Na (3,123 mg/l), and HCO3 (998 mg/l) when compared with WHO, BIS, and ISI standards. A positive correlation (r 2?=?0.82) was observed between Na and Cl, indicating its sources from salt water intrusion. Three factors were extracted with a total variance of 64% which indicates the sources of salinization, cation exchange, and anthropogenic impact to the groundwater. The Piper trilinear diagram indicates both Na–Cl and mixed Na–HCO3–Cl-type, indicating that groundwater was strongly affected by anthropogenic activities. The plot of (Ca?+?Mg)/(K?+?Na) indicates evidences of cation exchange and salt water intrusion. The (Ca–0.33*HCO3)/ SO4 plot indicates salt water intrusion for elevated SO4 levels rather than gypsum dissolution. The spatial distribution of total dissolved solid indicates the saline water encroachment along the SW part of the study area. As per sodium adsorption ratio (SAR), 50% of the samples with <10 SAR are suitable for irrigation and >10 SAR indicates that water is unsuitable for irrigation purposes. The residual sodium carbonate classification indicates that 50% of the samples fall in safe and 50% of the samples fall in bad zones and prolonged usage of this water will affect the crop yield. The Chloro Alkaline Index of water indicates disequilibrium due to a higher ratio of Cl?>?Na–K, indicating the influence of salt water intrusion. The Permeability Index of the groundwater indicates that the groundwater from the study area is moderate to good for irrigation purposes.  相似文献   

8.
Groundwater in Farashband plain, Southern Iran, is the main source of water for domestic and agricultural uses. This study was carried out to assess the overall water quality and identify major variables affecting the groundwater quality in Farashband plain. The hydrochemical study was undertaken by randomly collecting 84 groundwater samples from observation wells located in 13 different stations covering the entire plain in order to assess the quality of the groundwater through analysis of major ions. The water samples were analyzed for various physicochemical attributes. Groundwater is slightly alkaline and largely varies in chemical composition; e.g., electrical conductivity (EC) ranges from 2314 to 12,678 μS/cm. All the samples have total dissolved solid values above the desirable limit and belong to a very hard type. The abundance of the major ions is as follows: Na+ > Ca2+ > Ma2+ > K+ and Cl? > SO4 2– > HCO3 ?. Interpretation of analytical data shows three major hydrochemical facies (Ca–Cl, Na–Cl, and mixed Ca–Mg–Cl) in the study area. Salinity, total dissolved solids, total hardness, and sodium percentage (Na%) indicate that most of the groundwater samples are not suitable for irrigation as well as for domestic purposes and far from drinking water standard. A comparison of groundwater quality in relation to drinking water standards showed that most of the water samples are not suitable for drinking purposes. Based on the US salinity diagram, most of samples belong to high salinity and low to very high sodium type.  相似文献   

9.
This study was carried out to analyze groundwater quality in selected villages of Nalbari district, Assam, India, where groundwater is the main source of drinking water. 40 groundwater samples collected from hand pumps and analyzed for pH, EC, TDS, Ca2+, Mg2+, Na+, K+, HCO3 −, SO4 2−, Cl− and F−. Chemical analysis of the groundwater showed that mean concentration of cations in (mg/L) is in the order Ca2+ > Mg2+ > Na+ > K+ while for anions it is HCO3 − > Cl− > SO4 2− > F−. Fluoride concentration was recorded in the range of 0.02–1.56 mg/L. As per the desirable and maximum permissible limits for fluoride in drinking water recommended by WHO and by Bureau of Indian Standards (BIS), which is 1.5 mg/L, the groundwater of about 97% of the samples were found to be suitable for drinking purpose. The suitability of the groundwater for irrigation purpose was investigated by some determining factors such as sodium adsorption ratio, soluble sodium percentage, Kelly’s ratio and electrical conductivity. The value of the sodium absorption ratio and electrical conductivity of the groundwater samples were plotted in the US Salinity laboratory diagram for irrigation water. Most of the groundwater samples fall in the field of C2S1 and C3S1 indicating medium to high salinity and low sodium water, which can be used for irrigation on almost all types of soil with little doubt of exchangeable sodium. The hydrochemical facies shows that the groundwater is Ca-HCO3 type.  相似文献   

10.
In the management of water resources, quality of water is just as important as its quantity. In order to know the quality and/or suitability of groundwater for domestic and irrigation in upper Gunjanaeru River basin, 51 water samples in post-monsoon and 46 in pre-monsoon seasons were collected and analyzed for various parameters. Geological units are alluvium, shale and quartzite. Based on the analytical results, chemical indices like percent sodium, sodium adsorption ratio, residual sodium carbonate, permeability index (PI) and chloroalkaline indices were calculated. The pre-monsoon waters have low sodium hazard as compared to post-monsoon season. Residual sodium carbonate values revealed that one sample is not suitable in both the seasons for irrigation purposes due the occurrence of alkaline white patches and low permeability of the soil. PI values of both seasons revealed that the ground waters are generally suitable for irrigation. The positive values of Chloroalkaline indices in post-monsoon (80%) and in pre-monsoon (59%) water samples indicate absence of base-exchange reaction (chloroalkaline disequilibrium), and remaining samples of negative values of the ratios indicate base-exchange reaction (chloroalkaline equilibrium). Chadha rectangular diagram for geochemical classification and hydrochemical processes of groundwater for both seasons indicates that most of waters are Ca–Mg–HCO3 type. Assessment of water samples from various methods indicated that majority of the water samples in both seasons are suitable for different purposes except at Yanadipalle (sample no. 8) that requires precautionary measures. The overall quality of groundwater in post-monsoon season in all chemical constituents is on the higher side due to dissolution of surface pollutants during the infiltration and percolation of rainwater and at few places due to agricultural and domestic activities.  相似文献   

11.
Groundwater is the major source of fresh water in regions where there is inadequate surface water resources. Forty-seven groundwater samples were collected from Lower Ponnaiyar basin, Cuddalore District, south India, during the premonsoon (PRM) and postmonsoon (POM) seasons of 2005. Out of 47 groundwater samples, 15 samples showing higher nitrate concentration were those collected during PRM 2005. Microbial analysis of these samples was carried out by employing 16S rRNA gene sequence tool. Detailed analysis was conducted to determine the hydrogeochemical processes and microbial contamination responsible for deterioration of quality. The abundance of the ions during PRM and POM are in the following order: Na?>?Ca?>?Mg?>?K?=?Cl?>?HCO3?>?SO4?>?CO3. The dominant water types in PRM are in the order of NaCl?>?CaMgCl?>?mixed CaNaHCO3, whereas during POM NaCl?>?CaMgCl?>?mixed CaNaHCO3, and CaHCO3. However, NaCl and CaMgCl are major water types in the study area. The quality of groundwater in the study area is mainly impaired by surface contamination sources, mineral dissolution, ion exchange and evaporation. Groundwater chemistry was used to assess quality to ensure its suitability for drinking and irrigation, based on BIS and WHO standards. Suitability for irrigation was determined on the basis of the diagram of US Salinity Laboratory (USSL), sodium absorption ratio (SAR), residual sodium carbonate (RSC), and Na%. According to SAR and USSL classification, 27.66% (PRM) and 40.43% (POM) of samples fall under C3S2 category, indicating high salinity and medium sodium hazard, which restrict its suitability for irrigation. Microbiological analysis and its effects on the water quality were also addressed. The 16S rRNA gene sequences of 11 bacterial contaminants exhibited five groups with 11 operational taxonomic units with aerobic and facultatively anaerobic organisms. The presence of aerobic organisms in the groundwater samples reflects the active conversion of ammonia to nitrite by Nitrosomonas sp. which is further converted to nitrates by other organisms. Further the presence of nitrate reducers could also play a role in the process of conversion of nitrate to ammonia and nitrate to molecular nitrogen.  相似文献   

12.
Hydrogeochemical investigations are carried out in and around Perumal Lake, Cuddalore district, South India in order to assess its suitability in relation to domestic and agricultural uses. The water samples (surface water = 16; groundwater = 12) were analyzed for various physicochemical attributes like pH, electrical conductivity (EC), sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), chloride (Cl−), bicarbonate (HCO3 −), sulfate (SO4 2−), phosphate (PO4), silica (H4SiO4) and total dissolved solids (TDS). Major hydrochemical facies were identified using Piper trilinear diagram. Hydrogeochemical processes controlling the water chemistry are water–rock interaction rather than evaporation and precipitation. Interpretation of isotopic signatures reveals that groundwater samples recharged by meteoric water with few water–rock interactions. A comparison of water quality in relation to drinking water quality standard proves that the surface water samples are suitable for drinking purpose, whereas groundwater in some areas exceeds the permissible limit. Various determinants such as sodium absorption ratio (SAR), percent sodium (Na%), residual sodium carbonate (RSC) and permeability index (PI) revealed that most of the samples are suitable for irrigation.  相似文献   

13.
The chemical composition of 29 bore well water samples throughout the Kalpakkam region, South India, was determined to identify the major hydrogeochemical processes and the suitability of groundwater for domestic and irrigation purposes. The hydrochemical data were analyzed with reference to World Health Organization (WHO) standards and their hydrochemical facies were determined. The Piper plot shows that most of the groundwater samples fall in the field of mixed calcium–sodium–bicarbonate type followed by sodium–chloride, calcium–bicarbonate and mixed calcium–magnesium–chloride water types. The concentration of total dissolved solids exceeds the desirable limit in about 14% of samples; alkalinity values exceed the desirable limit in about 34% of the samples. The concentration of sulphate is well within the desirable limit at all the locations. The dominance of various heavy metals in the groundwater followed the sequence: Zn > Fe > Mn > Cu > Ni > Pb > Cr > Cd. Among the metal ions, the concentration of chromium and cadmium are within the permissible limit. Data are plotted on the US Salinity Laboratory diagram, which illustrates that most of the samples fall in the field of high salinity and low sodium hazard, which can be used to irrigate salt tolerant and semi-tolerant crops under favorable drainage conditions. Based on the analytical results, chemical indices like sodium adsorption ratio and residual sodium carbonate were calculated which show that most of the samples are good for irrigation.  相似文献   

14.
A total of 129 groundwater samples were collected in the Jangseong region of South Korea to characterize and evaluate groundwater quality and its suitability for irrigation and domestic uses. Samples were chemically analyzed for major ions, pH, electrical conductivity, and total dissolved solids following standard methods. The AquaChem 2014.2 model linked with PHREEQC was used for the statistical analysis and characterization of the hydrochemistry of the groundwater. The analysis showed that in all samples Ca–HCO3 was the leading water type and that the abundance of major cations was in the order Ca > Na > Mg > K, and of anions in the order HCO3 > Cl > SO4 > F. According to the correlation analysis, Ca showed strong interdependence with HCO3, suggesting that these parameters may have originated from common sources. Saturation index calculations indicated that all samples were undersaturated with respect to aragonite, calcite, dolomite, fluorite, gypsum, halite, and siderite, and oversaturated with respect to goethite and hematite. The irrigation suitability analysis revealed that groundwater in the Jangseong area can be used for irrigation without any restrictions based on EC, sodium adsorption ratio, percent sodium, residual sodium carbonate, Kelley ratio, permeability index, and the US Salinity Laboratory diagram analysis. The drinking water suitability analysis made for major parameters by comparison with the WHO guidelines indicates that the groundwater in the area is suitable for drinking except in some samples with high nitrate–N concentrations. The elevated nitrate concentrations in the groundwater are likely an indicator of agricultural pollution.  相似文献   

15.
Investigations were undertaken into the quality of surface water and groundwater bodies within the Upper Tigris Basin in Turkey to determine their suitability for potable and agricultural use. In the study area, the majority of the groundwater and surface water samples belong to the calcium–magnesium–bicarbonate type (Ca–Mg–HCO3) or magnesium–calcium–bicarbonate type (Mg–Ca–HCO3). Chemical analysis of all water samples shows that the mean cation concentrations (in mg/L) were in the order Ca2+ > Mg2+ > Na+ > K+ and that of anions are in the order \( \text{HCO}_{3}^{ - } \) > \( \text{SO}_{4}^{2 - } \) > Cl? > \( \text{CO}_{3}^{ - } \) for all groundwater and surface water samples. The Mg2+/Ca2+ ratio ranges from 0.21 to 1.30 with most of the values greater than 0.5, indicating that weathering of dolomites is dominant in groundwater. The analysis reveals that all of the samples are neutral to slightly alkaline (pH 7.0–8.7). Groundwater and surface water suitability for drinking usage was evaluated according to the World Health Organization and Turkish Standards (TSE-266) and suggests that most of the samples are suitable for drinking. Various determinants such as sodium absorption ratio, percent sodium (Na %), residual sodium carbonate and soluble sodium percentage revealed that most of the samples are suitable for irrigation. According to MH values, all of the well water samples were suitable for irrigation purposes, but 80 and 81.82% of Zillek springs and surface water samples were unsuitable. As per the PI values, the water samples from the study area are classified as Class I and Class II and are considered to be suitable for irrigation.  相似文献   

16.
This paper is an attempt to study the geochemistry of Akra Kaur Dam (AKD) water, north of Gwadar city, southern Balochistan. Representative water samples were collected from AKD reservoir to assess the suitability of water for drinking and agriculture purposes. The major ionic composition is suggestive for freshwater. The average ionic composition demonstrate SO4 > Ca > Na > Cl > HCO3 > Mg > K. The plots on Piper diagram reflected Ca–Mg–SO4 type of water facies. High Ca/SO4 and Ca/Mg ratios revealed that the water has influence of gypsum dissolution. The negative ratio of chloro-alkaline indices indicated reverse exchange between Ca and Mg in water occurred with Na and K in rocks. The pH, electrical conductivity, total dissolved salts, Ca, Mg, Na, K, HCO3, Cl and SO4 concentrations in the dam water were below the permissible limit, however, Na and SO4 were above the desirable limit, set by the World Health Organization. Important parameters such as residue sodium carbonate, sodium percent, sodium adsorption ratio, permeability index, magnesium content and Kelley’s ratio were calculated to evaluate the suitability of water for irrigation purpose. The result were compared with standard permissible limits and found satisfactory. The health and agriculture hazards of sulphate-bearing water were also discussed.  相似文献   

17.
A total of twenty-three water samples were collected in winter 2013 to assess groundwater quality in the Oued Rmel aquifer in the Zaghouan governate in Tunisia. These samples were subject to in-field measurements of some physico-chemical parameters (temperature, pH, and salinity), and laboratory analysis of major elements. Several parameters were used to assess the quality of water destined for irrigation, including electrical conductivity (EC) and sodium adsorption ratio (SAR). As part of this work, GIS was used to study spatial distributions of SAR, EC, residual sodium carbonate, sodium percentage (%Na), Doneen’s permeability index, Kelly’s ratio, and magnesium hazard and, therefore, evaluated the water quality of Oued Rmel (good, fair, or poor) regarding irrigation. The major ions most abundantly found in the waters of Oued Rmel were in the following order: Na+?>?Ca2+?>?Mg2+?>?K+ and Cl??>?SO42??>?HCO3. 56% of water samples from the Oued Rmel aquifer showed a low alkalinization risk, where SAR was lower than 10, 39% have a medium soil destabilization risks (10?<?SAR?<?18), and just 5% indicated high alkalinity hazards (SAR?>?26). Samples of water intended for irrigation showed a medium to high sodicity and alkalinization risk. It is expected that output may help in assessing the impacts of water quality of the Oued Rmel aquifer used for irrigation.  相似文献   

18.
The Kouh-e Zar mining area with iron oxide-rich types of Cu–Au (IOCG)-type gold mineralization is located in a fractured zone between two main “Darouneh” and “Taknar” faults in 35 km northwest of Torbat-e Heydarieh. In this study, the hydrogeochemistry and water quality of groundwater were examined for irrigation uses. Totally, 11 groundwater samples were collected in semi-arid area surrounding the mine. According to the irrigation water quality indices such as sodium absorption ratio, sodium percentage, residual sodium carbonate, residual sodium bicarbonate, potential salinity, salinity index, salinity hazard, permeability index and magnesium hazard, the water resources were appraised suitable to unsuitable. Na+ was a dominant cation and HCO3? was a dominant anion in the water samples. Fortunately, SO42? content is low (<?250 mg/L) in the water samples because of low-sulfide content mineralization in this mine. Water–rock interaction was defined as the controlling process on groundwater chemistry based on the Gibbs diagram. Calculated saturation indices revealed that the anion and cations in groundwater originated from dissolution of minerals and evaporation process. In the case of dominant Ca2+ and Mg2+, they were originated by dissolution of carbonate minerals such as calcite, dolomite and aragonite. Na+ was likely originated by plagioclase weathering in the brecciated volcanic rocks. Though the sulfidic mineralization is not so high in the Kouh-e Zar area, however, considering the existence of metalogenic mineralization in the Kouh-e Zar area, there is also a risk potential of release of toxic elements into the groundwater on which further deep investigation is ongoing in the area.  相似文献   

19.
The lower Varuna River basin in Varanasi district situated in the central Ganga plain is a highly productive agricultural area, and is also one of the fast growing urban areas in India. The agricultural and urbanization activities have a lot of impact on the groundwater quality of the study area. The river basin is underlain by Quaternary alluvial sediments consisting of clay, silt, sand and gravel of various grades. The hydrogeochemical study was undertaken by randomly collecting 75 groundwater samples from dug wells and hand pumps covering the entire basin in order to understand the sources of dissolved ions, and to assess the chemical quality of the groundwater through analysis of major ions. Based on the total dissolved solids, two groundwater samples are considered unsuitable for drinking purpose, but all samples are useful for irrigation. Graphical treatment of major ion chemistry by Piper diagram helps in identifying hydro-geochemical facies of groundwaters and the dominant hydrochemical facies is Ca-Mg-HCO3 with appreciable percentage of the water having mixed facies. As per Wilcox’s diagram and US Salinity laboratory classification, most of the groundwater samples are suitable for irrigation except two samples (No’s 30 and 68) which are unsuitable due to the presence of high salinity and medium sodium hazard. Irrigation waters classified based on residual sodium carbonate, have revealed that all groundwaters are in general safe for irrigation except one sample (No. 27), which needs treatment before use. Permeability index indicates that the groundwater samples are suitable for irrigation purpose. Although the general quality of groundwater of the lower Varuna River basin is suitable for irrigation purpose, fifty seven percent of the samples are found having nitrate content more than permissible limit (>45 mg/l) which is not good for human consumption. Application of N-Fertilizers on agricultural land as crop nutrients along the Varuna River course may be responsible for nitrate pollution in the groundwater due to leaching by applied irrigation water. The other potential sources of high nitrate concentration in extreme northern, southern and southwestern parts of study area are poor sewerage and drainage facilities, leakage of human excreta from very old septic tanks, and sanitary landfills. The high fluoride contamination (>1.5 mg/l) in some of the samples may be due to the dissolution of micaceous content in the alluvium. Nitrate and fluoride contamination of groundwater is a serious problem for its domestic use. Hence an immediate protective measure must be put into action in the study area.  相似文献   

20.
Regional study on the impact of variations in input rainfall over groundwater quality and its suitability for utilitarian purposes is essential for its extraction and management. Water chemistry from 456 observations wells for 2007–2011 period in hard rock Basaltic terrain of Upper Godavari basin is supported with 8 field samples (in 2014) in this analysis. Based on mean annual rainfall (MAR), four narrow climatic zones are identified in the basin, defined as “humid” (MAR > 1600 mm), “sub-humid” (1600–1000 mm), “semi-arid” (1000–600 mm), and “arid” (MAR < 600 mm). NICB ratio (<±10%), and anionic percentages demarcated the polluted areas from rest “good data”, composing of 1818 samples. Hydrochemical facies are studied using Piper diagram, secondary alkalinity exceeded 50% and not one cation–anion pair exceeded 50%, and silicate–carbonate plot, arid zone nearer to silicate pole indicated the dominance of SiO2 in Ca/Na vs Mg/Na plot. These geochemical variations emphasize a detailed study on role of climatic gradient on groundwater suitability for different purposes, for groundwater extraction, and its management. Suitability of groundwater for drinking based on water quality indices (WQI) indicated 98% of the samples as suitable (WQI < 50%). TDS in humid zone is 150–500 and 500–1000 mg/L in rest of the zones with ～68% in permissible range, 15% as hard water (TDS > 600 mg/L) and not acceptable for drinking. Suitability of groundwater for irrigation is studied using sodium percentage (Na %), Wilcox diagram, sodium absorption ratio (SAR), US salinity diagram, residual sodium carbonate (RSC), permeability index (PI), Kelly’s ratio (KR), ancd magnesium absorption ratio (MgAR). Na % in four zones is < 60% and permissible for irrigation. Very few water samples fall in “doubtful to unsuitable” and “unsuitable” category of Wilcox diagram. Region is observed to have SAR < 6, indicating that water would not cause any problem to the soil and crop. Humid and sub-humid zones belonged to C1S1 and C2S1 categories (low and medium sodium), while semi-arid extended to C3S1 category (salinity hazard zone) in US salinity plot. RSC for all the three zones ranged from 1 to 1.5 meq/L, with 90–95% of the area safe for irrigation. Out of 1818 samples, 1129 belonged to class 2 of PI classification (PI ranging from 25 to 75%) while rest 689 samples had PI >75% (class 1). KR varied from 0.05 to 12.81, with 70–80% of the area having KR < 1. MgAR ratio ranged from 67% to 96%, with sub-humid, humid zones having higher Mg concentrations (increased salinity). Thus, 90% of the samples indicated non-alkaline water with 1% of normal alkalinity. Hence, the current study systematically analyzed the effect of precipitation and geology on groundwater quality and on its usability for various purposes. This stepwise procedure categorized the regions, and the same can be adopted for any regional hydrogeochemical studies.  相似文献   

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