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1.
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   

2.
Submarine groundwater discharge (SGD) was quantified at select sites in San Francisco Bay (SFB) from radium (223Ra and 224Ra) and radon (222Rn) activities measured in groundwater and surface water using simple mass balance box models. Based on these models, discharge rates in South and Central Bays were 0.3?C7.4?m3?day?1?m?1. Although SGD fluxes at the two regions (Central and South Bays) of SFB were of the same order of magnitude, the dissolved inorganic nitrogen (DIN) species associated with SGD were different. In the South Bay, ammonium (NH 4 + ) concentrations in groundwater were three-fold higher than in open bay waters, and NH 4 + was the primary DIN form discharged by SGD. At the Central Bay site, the primary DIN form in groundwater and associated discharge was nitrate (NO 3 ? ). The stable isotope signatures (??15NNO3 and ??18ONO3) of NO 3 ? in the South Bay groundwater and surface waters were both consistent with NO 3 ? derived from NH 4 + that was isotopically enriched in 15N by NH 4 + volatilization. Based on the calculated SGD fluxes and groundwater nutrient concentrations, nutrient fluxes associated with SGD can account for up to 16?% of DIN and 22?% of DIP in South and Central Bays. The form of DIN contributed to surface waters from SGD may impact the ratio of NO 3 ? to NH 4 + available to phytoplankton with implications to bay productivity, phytoplankton species distribution, and nutrient uptake rates. This assessment of nutrient delivery via groundwater discharge in SFB may provide vital information for future bay ecological wellbeing and sensitivity to future environmental stressors.  相似文献   

3.
A study on the geochemistry of groundwater was carried out in a river basin of Andhra Pradesh to probe into the spatial controlling processes of groundwater contamination, using principal component analysis (PCA). The PCA transforms the chemical variables, pH, EC, Ca2+, Mg2+, Na+, K+, HCO \(_3^- \) , Cl?, SO \(_4^{2-} \) , NO \(_3^-\) and F?, into two orthogonal principal components (PC1 and PC2), accounting for 75% of the total variance of the data matrix. PC1 has high positive loadings of EC, Na+, Cl?, SO \(_4^{2-} \) , Mg2+ and Ca2+, representing a salinity controlled process of geogenic (mineral dissolution, ion exchange, and evaporation), anthropogenic (agricultural activities and domestic wastewaters), and marine (marine clay) origin. The PC2 loadings are highly positive for HCO \(_3^- \) , F?, pH and NO \(_3^- \) , attributing to the alkalinity and pollution controlled processes of geogenic and anthropogenic origins. The PC scores reflect the change of groundwater quality of geogenic origin from upstream to downstream area with an increase in concentration of chemical variables, which is due to anthropogenic and marine origins with varying topography, soil type, depth of water levels, and water usage. Thus, the groundwater quality shows a variation of chemical facies from Na+ > Ca2+ > Mg2+ > K+: HCO \(_3^- \) > Cl? > SO \(_4^{2-}>\) NO \(_3^- \) > F?at high topography to Na+ > Mg2+ > Ca2+ > K+: Cl? > HCO \(_3^- \) > SO \(_4^{2-}>\) NO \(_3^- \) > F? at low topography. With PCA, an effective tool for the spatial controlling processes of groundwater contamination, a subset of explored wells is indexed for continuous monitoring to optimize the expensive effort.  相似文献   

4.
In this study, the physicochemical parameters (Conductivity, pH, Cl?, HCO 3 ? , PO 4 3? , SO 4 2? , NO 3 ? , NO 2 ? , F?, TH, Ca2+, K+, Mg2+, Na+, and DS) were determined for 41 samples collected from fourteen places in Algeria. The temperature of the thermal water samples at collection sites varied from 26°C to 86°C. pH values varied from 6.5 to 8.5 (i.e., from slightly acidic to moderately alkaline); 90.24% of the samples exhibited relatively high salinity (DS?=?550–5,500 mg L?1). Total hardness measurements indicated these waters to be moderately hard. Forty-six percent of the samples are Na–Cl in character. The ratios Na+/Ca2+, Na+/Mg2+, and (Na+ + K+)/(Ca2+ + Mg2+) were high in 90.24% of the samples. This indicates the ion exchange process is important, which indicates that most of the Algerian thermal waters had developed over a long period at a depth sufficient to react with the rock. Statistical analyses of the physicochemical data gave positive correlation values, thereby enabling good interpretation of the results and revealing the composition of ions present in the thermal waters, as well as some information about their origin. The therapeutic properties associated with thermal waters encourage people at spas to drink the water they bathe in. Therefore, we examined the drinkability of these thermal waters. World Health Organization (WHO 1993) standards were used to evaluate the thermal water quality for drinking. With respect to hardness, the samples were classified as moderately hard (58.54% of the samples), very hard (36.58% of the samples), and soft (4.88% of the samples). The drinkability study shows that only 16 samples of the investigated waters were drinkable and thus could be consumed without special precaution.  相似文献   

5.
Hydrogeochemical investigations were carried out around Fetzara Lake, Northeast Algeria, to assess the quality of groundwater for its suitability for drinking and irrigation purposes. The groundwater chemistry is mainly controlled by the water?Crock interactions, but also influenced by other processes such as evapotranspiration and ion exchange. Groundwater samples collected, during two periods (1993 and 2007) from wells in the area were analyzed for pH, EC, TDS, Ca2+, Mg2+, Na+, K+, CO 3 2? , HCO 3 ? , Cl?, SO 4 2? , and NO 3 ? . The chemical relationships in Piper??s diagram and Gibbs??s diagram suggest that groundwaters mainly belong to noncarbonate alkali type and Cl? group and are controlled by evaporation dominance, respectively, due to the sluggish drainage conditions, greater water?Crock interaction, and anthropogenic activities. A comparison of the groundwater quality in relation to drinking water quality standards proves that most of the water samples are not suitable for drinking. US Salinity Laboratory??s and Wilcox??s diagrams and %Na+ used for evaluating the water quality for irrigation suggest that the majority of the groundwater samples are not good for irrigation.  相似文献   

6.
One hundred forty-eight groundwater samples were collected from the lower part of Wadi Siham catchment area for hydrogeochemical investigations to understand the hydrogeochemical processes affecting groundwater chemistry and their relation with groundwater quality. Groundwater in the study area is abstracted from different aquifers. The study area is characterized by arid climate and extremely high relative humidity. The results indicate that groundwater in the study area is fresh to brackish in nature. The abundance of the major ions is as follows: Na+1?>?Ca+2?>?Mg+2?≥?K+1 and Cl?1?>?HCO 3 ?1 ?>?SO 4 ?2 ?>?NO 3 ?1 . Various graphical and ionic ration plots, statistical analyses, and saturation indices calculations have been carried out using chemical data to deduce a hydrochemical evaluation of the study area. The prevailing hydrogeochemical processes operating in the study area are dissolution, mixing, evaporation, ion exchange, and weathering of silicate minerals in the eastern part (recharge areas). The reverse ion exchange and seawater intrusion control the groundwater chemistry along the Red Sea coast areas and few parts of the study area. Deterioration in groundwater quality from anthropogenic activities has resulted from saltwater intrusion along the coastal areas due to groundwater overpumping and extensive use of fertilizers and infiltration of sewage water. Salinity and nitrate contamination are the two major problems in the area, which is alarming considering the use of this water for drinking.  相似文献   

7.
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   

8.
Electric dipole polarizabilities have been calculated from first principles of quantum mechanics for the BO 3 3? , CO 3 2? , NO 3 ? series and for NO 2 ? and LiNO3(g). Calculated trends in average polarizability and polarizability anisotropy in the BO 3 3? -NO 3 ? series are in agreement with experiment and can be qualitatively interpreted in terms of the varying energies of the a1′, a2″ and e′ symmetry unoccupied MO's of the oxyanions. Embedding a CO 3 2? ion in a D3h symmetry array of divalent cations reduces both the average polarizability and its anisotropy, particularly when diffuse s and p functions are included in the calculation. Calculations on the gas phase LiNO3 molecule and on the free NO 3 ? ion in the distorted geometry found in LiNO3(g) allow us to separate polarizability contributions internal to the NO 3 ? and Li+ ions from those which arise from the Li+-NO 3 ? interaction. The Li+-NO 3 ? interaction term so obtained is much smaller than the NO 3 ? contribution but is in turn larger than the Li+ contribution, suggesting that the inclusion of this interaction term is essential for obtaining accurate results for ion pairs. Although static polarizabilities are in reasonable agreement with experiment for NO 3 ? the wavelength dispersion of the polarizability is underestimated by about a factor of two, apparently as a result of inadequacies in the quantum mechanical method. Calculated values are also presented for 14N NMR shieldings in the nitrogen oxyanions but these are in only qualitative agreement with the experimental values. Similarly, calculated values of magnetic susceptibility are in only qualitative agreement with experiment although trends along the BO 3 3? -NO 3 ? series are properly reproduced.  相似文献   

9.
An investigation on quality of groundwater has been carried out in the river basin of Varaha located in Visakhapatnam District, Andhra Pradesh to find out the factors that are responsible for spatial variations of water vulnerability. The study area is underlain by the Precambrian rocks of Eastern Ghats over which the Recent Formations occur. Groundwater is a prime source for drinking and irrigation. The quality of groundwater is fresh and brackish with dominance of the latter. Groundwater samples are categorized into two major clusters A and B, using the dendrogram of cluster analyses. Out of these two major clusters, five sub-clusters I to V in the pre-monsoon season and six sub-clusters I to VI in the post-monsoon season are identified. The sub-clusters I to IV of pre-monsoon and I to V of post-monsoon seasons of the cluster A are characterized by less mineralized groundwater compared to those of V of pre-monsoon and VI of post-monsoon seasons of the cluster B, which represent highly mineralized groundwater. The low to high mineral content follows gradually from upstream to the downstream area, being higher in post-monsoon season in both the clusters A and B, depending upon the source, mineral dissolution, and precipitation, solubility and leaching of ions, ion exchange and adsorption processes. Spatial distributions of the sub-clusters give clues to understand the factors that cause variations of groundwater vulnerability at a specific site, vis-a-vis local and regional lithological and non-lithological influences. As a result, the quality of groundwater on a regional scale changes from Na+ > Mg2+ >Ca2+ > K+: HCO 3 ? > Cl? > SO 4 2? > NO 3 ? > F? in the cluster A to Na+ > Mg2+ >Ca2+ > K+: Cl? > HCO 3 ? > SO 4 2? > NO 3 ? > F? in the cluster B, following the topography. The classification of the area into the zones of relative groundwater vulnerability with respect to drinking water quality of the chemical composition of the sub-clusters helps the planners to identify the specific locations, where the inferior quality of groundwater can occur, for taking the remedial measures.  相似文献   

10.
A floodplain aquifer within an agricultural watershed near Madison, Wisconsin (USA), was studied to determine whether denitrification was occurring below the surface organic layer. Groundwater levels and concentrations of O2, Cl?, NO 3 ? , SO 4 2? , dissolved organic carbon (DOC), and major cations were monitored over a 1-year period along a 230-m transect between an agricultural field and a stream discharge point. Seventeen groundwater samples were analyzed for δ15NNO3 and δ18ONO3 composition. Samples in which NO 3 ? was too low for stable isotope analysis were analyzed for excess dissolved N2. Groundwater NO 3 ? concentrations declined between the agricultural field and the discharge point. Chloride and δ15NNO3/δ18ONO3 data indicated that the drop in NO 3 ? was caused primarily by dilution of shallow NO 3 ? -rich water with deeper, NO 3 ? -depleted groundwater. Two localized zones of denitrification were identified in the upland-wetland transition by their δ15NNO3 and δ18ONO3 signatures, and two in the stream hyporheic zone by the presence of excess dissolved N2. The combined stratigraphic, hydrologic, and geochemical data in these locations correspond to groundwater mixing zones where NO 3 ? is delivered to subsurface layers that support denitrification fueled by dissolved (e.g. DOC or dissolved Fe(II)) and/or solid-phase (e.g. particulate organic carbon, solid-associated Fe(II), or pyrite) electron donors.  相似文献   

11.
The groundwater system of the Eva Verda basin (Saint Marcel Valley, southern side of the middle Aosta Valley, Italy) has many springs that can be used as sources for drinking water. This area is near the disused Servette mine, which can be a pollutant source (metals and sulfides) for the springs located downhill. Aquifer characterization was done using a multidisciplinary approach: geostructural, lithological, hydrogeological and geochemical. In particular, the geostructural analysis showed that the preferential water-flow direction is controlled by tectonics and that it has a trend along the slope toward the downhill springs. The mine drainage flow direction is in agreement with this trend and can pollute the springs. Chemical analysis revealed three water groups: (1) SO 4 2- –Ca2+–Mg2+ rich water (mine drainage), (2) HCO 3 - –SO 4 2- –Ca2+ rich water and (3) HCO 3 - –Ca2+ rich water (freshwater). The second group of water results from the different percentage mix between the first and the third waters. The low percentage of mine polluted water demonstrates that there is a high dilution and low pollution of waters that can be exploited for drinking.  相似文献   

12.
Groundwater, surface water, soil and river sediment samples, and information on land use in the Nanfei River basin (NRB) of China have been analyzed to study the geochemistry, distribution, and mobilization of phosphorus. The distribution of phosphate (PO 4 3??/sup> ) and the relationships between PO 4 3??/sup> and several constituents in groundwater were studied. Partial correlation analysis relating PO 4 3??/sup> to types of land use was conducted using the data analyzing tool SPSS 15.0. The processes controlling the transport of PO 4 3??/sup> are discussed. The conclusions from this study are: (1) urban land use has obvious impact on PO 4 3??/sup> in groundwater, the average concentration of PO 4 3??/sup> being 4.37?mg/L, greater than that resulting from farmland and mixed land use, which have average PO 4 3??/sup> concentrations of 0.10 and 0.18?mg/L, respectively; (2) the partial correlation between PO 4 3??/sup> and types of land use is significant with a coefficient of 0.760; (3) the PO 4 3??/sup> concentrations in surface water are generally higher than those in groundwater, and the total phosphorus (TP) concentrations in river sediments are generally higher than those in soil samples; (4) groundwater is a carrier of PO 4 3??/sup> and is likely responsible for the redistribution of PO 4 3??/sup> in different regions of NRB.  相似文献   

13.
An experimental study of the particulars of the solubility and crystallization of brushite Ca(HPO4) · 2H2O from aqueous solution in conditions of a variable pH (6.0–3.0) and the contents of impurity ions (K+, Na+, NH 4 + , Mg2+, SO 4 2? , CO 3 2? ) has been conducted. It is established that brushite solubility markedly rises with a decrease in pH from 6 to 3 and slightly rises with an increase in Mg2+ and SO 4 2? concentrations. The enrichment in K+, Na+, and NH 4 + does not affect brushite solubility. The changeable chemistry of the medium results in variation of the synthetic crystal habit, from rhombic tabular to thickened prismatic crystals.  相似文献   

14.
The chemistry of soil solutions can be altered by human activities, due to the intense agricultural and husbandry, leading to leaching of nutrients and subsequently elevating ground water levels. Multivariate statistical and inverse geochemical modeling techniques were used to determine the main factors controlling soil solution chemistry of calcareous soils. In this research, a total of 21 calcareous soils was characterized and assessed for soil solution using soil column. The major cations in the studied soil solutions were in the decreasing order as Ca2+ > Mg2+ > Na+ > K+. The anions were also arranged in decreasing order as HCO $ _{3}^{ - } $  > Cl $ ^{ - } $  > SO $ _{4}^{2 - } $  > NO $ _{3}^{ - } $ . Concentrations of NO $ _{3}^{ - } $ , P, and K+ in soil solutions were in the range of 6.8–307.5 mg l?1 (mean 63.2 mg l?1), 5.0–10.4 mg l?1 (mean 5.9 mg l?1), and 2.8–54.6 mg l?1 (mean 11.3 mg l?1), respectively. Results suggest that the concentration of P in the soil solutions could be primarily controlled by the solubility of dicalcium phosphate dihydrate and dicalcium phosphate. Interactions between soil properties and observed solubility of nutrients were described, and put into empirical multivariate formulations. Obtained equations contained electrical conductivity (EC) as a key factor in determining nutrients solubility. Inverse geochemical modeling of soil solution using PHREEQC indicates the dissolution of calcite, anhydrite, halite, CO2 (g), N2 (g), and hydroxyapatite, and precipitation of sulfur. Cation exchange between Ca2+, Mg2+, K+ and Na+ occurred with Mg2+ and K+ into the solution, and Ca2+ and Na+ out of the solution. Determination of soil solution will improve soil management in the area, and preventing groundwater deterioration.  相似文献   

15.
Irrigation in semi-arid agricultural regions can have profound effects on recharge rates and the quality of shallow groundwater. This study coupled stable isotopes (2??, 18O), age-tracers (3H, CFCs, 14C), 87Sr/86Sr ratios, and elemental chemistry to determine the sources, residence times, and flowpaths of groundwater and agricultural contaminants (e.g. NO 3 ?C ) in the Saddle Mountains Basalt Aquifer in central Washington, USA, where over 80% of the population depend on groundwater for domestic use. Results demonstrate the presence of two distinct types of water: contaminated irrigation water and pristine regional groundwater. Contaminated irrigation water has high NO 3 ?C concentrations (11?C116? mg/l), 87Sr/86Sr ratios (0.70659?C0.71078) within range of nitrogen-based fertilizers, detectable tritium (2.8?C13.4 TU), CFC ages 20?C40?years, high ??18O values (?16.9 to ?13.5??), and ??100 percent modern 14C. Pristine regional groundwater has low NO 3 ?C concentrations (1?C5? mg/l), no detectable tritium (??0.8 TU), low ??18O values (?18.9 to ?17.3??) and 14C ages from ??15 to 33?ky BP. Nitrogen and oxygen isotopes of NO 3 ?C , combined with high dissolved oxygen values, show that denitrification is not an important process in the organic-poor basalt aquifers resulting in transport of high NO 3 ?C irrigation water to depths greater than 40?m in less than 30? years.  相似文献   

16.
The electron paramagnetic resonance (EPR) spectra of Fe3+ in a well cristallized kaolinite from Decazeville in France are well resolved. It is shown that in this sample there are mainly two slightly different spectra, well separated at low temperature and characterized at -150° C by the constants B 2 0 = 0.112 cm?1, B 2 2 = 0.0688 cm?1 for one and B 2 0 = 0.116 cm?1, B 2 2 = 0.0766 cm?1 for the second. These two spectra arise from Fe3+ substituted for Al3+ at the two octahedral positions in equal amounts. The temperature dependence of EPR spectra was studied and was explained by a modification of the octahedral sites.  相似文献   

17.
The carbonate (CO 3 ?2 ) produced by Sporosarcina pasteurii was injected electrokinetically to enhance the mechanical properties of soft clay soils. In this method the Ca2+ was injected into the anode chamber and moved towards the cathode by electromigration and electroosmotic flow. Then the released CO 3 ?2 from a blend of bacteria and urea was injected into the cathode chamber. The CO 3 ?2 ions were moved from the cathode to the anode under electromigration mechanism. The CaCO3 was precipitated in the presence of calcium in porous medium of the soil, and consequently increased the shear strength of the soil. The polarity reversal was applied to have a homogeneous distribution of CaCO3.  相似文献   

18.
Shallow groundwater (>30 mbgl) is an essential source of drinking water to rural communities in the Ndop plain, northwest Cameroon. As a contribution to water management, the effect of seasonal variation on the groundwater chemistry, hydrochemical controls, drinking quality and recharge were investigated during the peaks of the dry (January) and rainy (September) seasons. Field measurements of physical parameters were preceded by sampling 58 groundwater samples during both seasons for major ions and stable isotope analyses. The groundwater, which was barely acidic (mean pH of 6) and less mineralised (TDS < 272 mg/l), showed no significant seasonal variation in temperature, pH and TDS during the two seasons. The order of cation abundance (meq/l) was Na+ > Ca2+ > Mg2+ > K+ and Na+ > Mg2+ > Ca2+ > K+ in the dry and rainy seasons, respectively, but that of anions ( \( {\text{HCO}}_{3}^{ - } \)  >  \( {\text{NO}}_{3}^{ - } \)  > Cl? >  \( {\text{SO}}_{4}^{2 - } \)  > F?) was similar in both seasons. This suggests a negligible effect of seasonal variations on groundwater chemistry. The groundwater, which was CaMgHCO3 and NaHCO3, is chemically evolved rainfall (CaMgSO4Cl) in the area. Silicate mineral dissolution and cation-exchange were the main controls on groundwater chemistry while there was little anthropogenic influence. The major ions and TDS concentrations classified the water as suitable for human consumption as per WHO guidelines. The narrow cluster of δ18O and δD of same groundwater from both seasons between the δ18O and δD values of May–June precipitation along the Ndop Meteoric Water Line indicates meteoric origin, rapid recharge (after precipitation) and timing of recharge between May and June rainfall. Diffuse groundwater recharge mainly occurs at low altitudes (<1,400 m asl) within the plain. Besides major ions and TDS, the similar δ18O and δD of groundwater from both seasons indicate a consistent groundwater recharge and flow pattern throughout the year and resilience to present day short-term seasonal climatic variations. However, controlled groundwater abstraction is recommended given the increasing demand.  相似文献   

19.
El Shalal-Kema area is located east of Aswan town and Nile River. The Quaternary sediments (unconsolidated material of sands, gravels, and clays intercalation) represent the main aquifer in the studied area. Its water is under unconfined condition, and the water table is shallow (vary from 7.5 to 16.3 m). The concerned aquifer is recharged mainly from Aswan Dam Lake, from the excess irrigation water and from septic tanks, where the area is not served by sewage system. The direction of the groundwater movement is generally from south to north. The transmissivity values of the Quaternary aquifer (from three pumping tests) are relatively high (vary from 1,996 to 3,029 m2/day). The exploitation of groundwater is carried out where there is continuous withdrawal for industrial and domestic uses with a total average quantity of groundwater of 71,304 m3 per day (25.67 million m3 per year). The hydrochemical characteristics of the Quaternary aquifer is studied based on the chemical analysis of 29 groundwater and four surface water samples collected from different sites. The chemical composition of the groundwater is dominated by calcium Ca2+ from the cations and bicarbonate (HCO 3 ? ) from the anions, and the order of cation abundance is Ca2+ > Na+ > Mg2+ > K+ and HCO 3 ? > SO 4 2? > Cl? among the anions. The groundwater types are normal chloride water, normal sulfate water, and normal carbonate water. The hypothetical salt combination revealed the presence of different salts arranged in terms of their predominant as Ca(HCO3)2, Mg(HCO3)2, NaCl, Na2SO4, MgSO4, KCL, NaHCO3, MgCl2, CaSO4, and K2SO4. The analytical measurements to the NO2 and NH3 reveal that their values decrease in summer and increase in winter due to the stoppage of pumping which leads to the increase of the wastewater quantities that reach the groundwater. The chemical and microbiological analyses show that the aquifer in this area is contaminated with fecal and disease-causing bacteria. The main cause of this contamination is the outflow from the septic tanks; therefore, the construction of sewage network is a vital solution. Chlorination is important to disinfect the groundwater at the tanks before its distribution to the houses.  相似文献   

20.
In semi-arid/arid regions, groundwater is the major source of irrigation, drinking and industrial requirements, water salinity and shortage are major problems of concern. North Gujarat, India, is one such area where highly saline groundwater is generally ascribed to rapid increase of population, agriculture and industries induced decline in water table by unplanned abstraction of groundwater. However, no effort has been made to discriminate the natural and anthropogenic influences on groundwater salinity. In this brief background, the present study attempts to identify the factors and processes controlling the groundwater salinity in the area, based on ionic ratios in integration with various graphical methods, saturation indices and geographical information system. Na+/Ca2+ > 1 indicates the deficiency of Ca2+ possibly due to CaCO3 precipitation or ion exchange process. Na+/Cl? > 1 and $ {\text{SO}}_{4}{}^{2 - } /{\text{Cl}}^{ - } \gg 0.05 $ suggest salinization is mainly due to wastewater infiltration and/or due to irrigation water return flow. Sea water intrusion in coastal parts, vertical and lateral mixing of water and anthropogenic inputs are also responsible for salinization of groundwater. USSL diagram, Na%, sodium adsorption ratio, residual sodium carbonate and magnesium hazard indicate unsuitability of groundwater for irrigation purposes. To prevent groundwater salinization, appropriate measures need to be taken to control further indiscriminate exploitation of groundwater for irrigation.  相似文献   

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