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1.
Tahir Rafique Shahid Naseem Muhammad I. Bhanger Tanzil H. Usmani 《Environmental Geology》2008,56(2):317-326
Groundwater samples were collected from various localities of Mithi sub-district of the Thar Desert of Pakistan and analysed
for fluoride ion along with other chemical parameters. The area is mainly covered by sand dunes and kaolin/granite at variable
depths. Results showed that collected water samples were severely contaminated by the presence of fluoride ion and most of
the samples have higher concentration than prescribed WHO standards (1.5 mg/l) for drinking water. Fluoride ion concentrations
ranged between 0.09 and 11.63 mg/l with mean and median values of 3.64 and 3.44 mg/l, respectively, in this area whereas,
distribution pattern showed high concentrations in the vicinity of Islamkot and Mithi towns. The content of F− has also been correlated with other major ions found in the groundwater of the study area. The positive correlation of F− with Na+ and HCO3
− showed that the water with high Na+ and HCO3
− stabilizes F− ions in the groundwater of the Thar Desert. The pH versus F− plots signifies high fluoride concentration at higher pH values, implying that alkaline environment favours the replacement
of exchangeable OH− with F− in the groundwater of Mithi area. The saturation indices (SI) of fluorite (CaF2) and calcite (CaCO3) in the groundwater samples showed that most of the samples are oversaturated with respect to calcite whereas majority of
samples have been found under saturated with respect to fluorite. The log TDS and Na/Na+Ca ratio reflected supremacy of weathering
of rocks, which promotes the availability of fluoride ions in the groundwater. Piper diagram has been used to classify the
hydrofacies. In the cation triangle, all samples are Na-type, while the anion triangle reflects major dominance of Cl-type
with a minor influence of HCO3
− and SO4
−. 相似文献
2.
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
3.
The effects of a number of inorganic anions (F−, HCO3
−, B(OH)4−, Cl−, I−) and of the siderophore DFO-B on the release of As from volcanic rocks were investigated in batch experiments. While previously
reported field and laboratory data support a role of inorganic anions on As mobilization into aquifers, the role of siderophores
on As-induced mobilization was less investigated. Fluoride, bicarbonate and DFO-B have shown a significant influence on the
release of As from the rocks. Lava was mostly affected among the investigated rocks at pH 6 and 20°C by releasing 4% of its
initial As content in the presence of 0.01 M F−and 10% in the presence of 500 μM DFO-B. The effect of fluoride was larger at pH 6 than at pH 8.5 for all the rocks. In the
case of DFO-B, there was also a larger effect at pH 6 compared to pH 8 for the various rocks except tuff. Bicarbonate played
a role under alkaline conditions while its effect was negligible at pH 6. Anion exchange processes in the presence of fluoride
and bicarbonate and complexation processes in the presence of the siderophore DFO-B appear to be the major processes responsible
for the release of arsenic from the rocks. The siderophore DFO-B plays mainly an indirect role on the As release by complexing
Al, Fe and Mn, thus favoring the dissolution of the rocks and the consequent release of As bound to surface Al, Fe and Mn
oxy-hydroxides. These findings suggest that ionic interactions with fluoride, bicarbonate and siderophore may be a further
triggering factor in the mobilization of As from aquifer rocks. 相似文献
4.
Influence of hydrogeochemical processes on temporal changes in groundwater quality in a part of Nalgonda district, Andhra Pradesh, India 总被引:4,自引:3,他引:1
Geochemical processes that take place in the aquifer have played a major role in spatial and temporal variations of groundwater
quality. This study was carried out with an objective of identifying the hydrogeochemical processes that controls the groundwater
quality in a weathered hard rock aquifer in a part of Nalgonda district, Andhra Pradesh, India. Groundwater samples were collected
from 45 wells once every 2 months from March 2008 to September 2009. Chemical parameters of groundwater such as groundwater
level, EC and pH were measured insitu. The major ion concentrations such as Ca2+, Mg2+, Na+, K+, Cl−, and SO4
2− were analyzed using ion chromatograph. CO3
− and HCO3
− concentration was determined by acid–base titration. The abundance of major cation concentration in groundwater is as Na+ > Ca2+ > Mg2+ > K+ while that of anions is HCO3
− > SO4
2− > Cl− > CO3
−. Ca–HCO3, Na–Cl, Ca–Na–HCO3 and Ca–Mg–Cl are the dominant groundwater types in this area. Relation between temporal variation in groundwater level and
saturation index of minerals reveals the evaporation process. The ion-exchange process controls the concentration of ions
such as calcium, magnesium and sodium. The ionic ratio of Ca/Mg explains the contribution of calcite and dolomite to groundwater.
In general, the geochemical processes and temporal variation of groundwater in this area are influenced by evaporation processes,
ion exchange and dissolution of minerals. 相似文献
5.
D. John Devadas N. Subba Rao B. Thirupathi Rao K. V. Srinivasa Rao A. Subrahmanyam 《Environmental Geology》2007,52(7):1331-1342
Systematic hydrogeochemical survey has been carried out for understanding the sources of dissolved ions in the groundwaters
of the area occupied by Sarada river basin, Visakhapatnam district, Andhra Pradesh, India. Khondalites, charnockites and granite
gneisses and calc-granulites of Precambrians and alluvial deposits of Quaternaries underlie the study area. Groundwaters are
both fresh and brackish; the latter waters being a dominant. Most groundwaters are characterized by Na+:HCO3− facies due to chemical weathering of the rocks. Enrichment of Na+, K+, Cl−, SO42−, NO3− and F− in some groundwater samples is caused by seawater intrusion, locally accompanied by ion-exchange, and anthropogenic activities,
resulting in an increase of brackish in the groundwaters. Based on the results of this hydrogeochemical study, suitable management
measures are recommended to solve the water quality problems. 相似文献
6.
Water samples collected from dug wells and tube wells from the Kurunegala District of Sri Lanka have been studied for their
major hydrogeochemical parameters to understand the chemical quality of water in the terrain. The region is composed of Precambrian
metamorphic rocks where groundwater is only available in the regolith and along weak structural discontinuities. The study
of the major chemical constituents of groundwater revealed several relationships with the aquifer lithology. Groundwater from
mafic rocks have high dissolved solids, while quartzose metaclastic rocks yield water with low dissolved solids. The study
area displays very low SO4
2− contents of the groundwater. The chloride content is higher in the dry regions and in terrains underlain by pink granite
and marble/calc gneiss while areas with marble, as expected, show high concentrations of Ca and Mg ions. The waters in the
region can be classified into non-dominant cations to Na + K dominant and Cl− and HCO3
− dominant types. Water from charnockite-bearing areas tends to have non-dominant cations and more CO3
2− + HCO3
− types. Effects such as soluble salts in the regolith, fracture intensity and climatic variations play a significant role
in the behavior of the hydrogeochemistry in the area. 相似文献
7.
The groundwaters from Zhongxiang City, Hubei Province of central China, have high fluoride concentration up to 3.67 mg/L,
and cases of dental fluorosis have been found in this region. To delineate the nature and extent of high fluoride groundwaters
and to assess the major geochemical factors controlling the fluoride enrichment in groundwater, 14 groundwater samples and
5 Quaternary sediment samples were collected and their chemistry were determined in this study. Some water samples from fissured
hard rock aquifers and Quaternary aquifers have high fluoride concentrations, whereas all karst water samples contain fluoride
less than 1.5 mg/L due to their high Ca/Na ratios. For the high fluoride groundwaters in the fissured hard rocks, high HCO3
− concentration and alkaline condition favor dissolution of fluorite and anion exchange between OH− in groundwater and exchangeable F− in some fluoride-bearing minerals. For fluoride enrichment in groundwaters of Quaternary aquifers, high contents of fluoride
in the aquifer sediments and evapotranspiration are important controls. 相似文献
8.
Shekhar Gupta P. S. Dandele M. B. Verma P. B. Maithani 《Journal of the Geological Society of India》2009,73(2):202-212
Groundwater in Palnad sub-basin is alkaline in nature and Na+-Cl−-HCO3− type around Macherla-Karempudi area in Guntur district, Andhra Pradesh. Total dissolved solids (TDS) show strong positive
correlation with Cl−, Na+, Ca2+ and Mg2+, and positive correlation with SO42−, K+ and HCO3−. Calcareous Narji Formation is the dominant aquifer lithology, and water-rock interaction controls the groundwater chemistry
of the area. Chloro-alkaline indices (CAI) are positive at Miriyala, Adigopula, Mutukuru, Macherla and Durgi suggesting replacement
of Na+ and K+ ions from water by Mg++ and Ca++ ions from country rock through base exchange reactions. Negative CAI values are recorded at Terala, Rayavaram and Nehrunagar,
which indicate exchange of Na+ and K+ from the rock as cation-anion exchange reaction (chloro-alkaline disequilibrium).
TDS range from 91 to 7100 ppm (Avg. 835 ppm) and exceed the prescribed limit of drinking water around Mutukuru, Durgi, Rayavaram,
Khambampadu and Ammanizamalmadaka areas. Scanty rainfall and insufficient groundwater recharge are the prime factors responsible
for high salinity in the area. Fluoride content ranges from <1 to 3.8 ppm and contaminated areas were identified around Macherla
(1 sq km; 3.8ppm), Mandadi (1 sq km, 2.1ppm) and Adigopula (2 sq km, <1 to 3.7 ppm). The % Na+ content varies from 17 to 85 with the mean value of 57, and eighty (80) samples showed higher %Na+ in comparison to the prescribed limit of 60 for irrigation water. Sodium Adsorption Ratio (SAR) and % Na+ in relation to total salt concentration indicate that groundwater (51%) mostly falls under doubtful to poor quality for irrigation
purpose. Groundwater of Adigopula village is fluoride contaminated and remedial measures are suggested to improve the water
quality. 相似文献
9.
High fluoride groundwater occurs in Maku area, in the north of West Azarbaijan province, northwest of Iran. Groundwater is
the main source of drinking water for the area residents. Groundwater samples were collected from 72 selected points including
40 basaltic and 32 nonbasaltic springs and wells, in two stages, during June and August 2006. The areas with high fluoride
concentrations have been identified, and the possible causes for its variation have been investigated. Regional hydrogeochemical
investigation indicates that water-rock interaction is probably the main reason for the high concentration of ions in groundwater.
The concentration of F− in groundwater is positively correlated with that of HCO3
− and Na+, indicating that groundwater with high HCO3
− and Na+ concentrations help to dissolve some fluoride-rich minerals. All of the water samples, collected from the basaltic areas
do not meet the water quality standards for fluoride concentration and some other parameters. Hence, it is not suitable for
consumption without any prior treatment. Inhabitants of the area that obtain their drinking water supplies from basaltic springs
and wells are suffering from dental fluorosis. The population of the study area is at a high risk due to excessive fluoride
intake especially when they are unaware of the amount of fluoride being ingested due to lack of awareness. 相似文献
10.
A holistic study of the composition of the basalt groundwaters of the Atherton Tablelands region in Queensland, Australia
was undertaken to elucidate possible mechanisms for the evolution of these very low salinity, silica- and bicarbonate-rich
groundwaters. It is proposed that aluminosilicate mineral weathering is the major contributing process to the overall composition
of the basalt groundwaters. The groundwaters approach equilibrium with respect to the primary minerals with increasing pH
and are mostly in equilibrium with the major secondary minerals (kaolinite and smectite), and other secondary phases such
as goethite, hematite, and gibbsite, which are common accessory minerals in the Atherton basalts. The mineralogy of the basalt
rocks, which has been examined using X-ray diffraction and whole rock geochemistry methods, supports the proposed model for
the hydrogeochemical evolution of these groundwaters: precipitation + CO2 (atmospheric + soil) + pyroxene + feldspars + olivine yields H4SiO4, HCO3
−, Mg2+, Na+, Ca2+ + kaolinite and smectite clays + amorphous or crystalline silica + accessory minerals (hematite, goethite, gibbsite, carbonates,
zeolites, and pyrite). The variations in the mineralogical content of these basalts also provide insights into the controls
on groundwater storage and movement in this aquifer system. The fresh and weathered vesicular basalts are considered to be
important in terms of zones of groundwater occurrence, while the fractures in the massive basalt are important pathways for
groundwater movement. 相似文献
11.
Hydrochemical investigations were carried out in Damagh area, Hamadan, western Iran, to assess chemical composition of groundwater.
Forty representative groundwater samples were collected from different wells to monitor the water chemistry of various ions.
Chemical analysis of the groundwater showed that the mean concentration of the cations is in the order Na+ > Ca2+ > Mg2+ > K+, while that for anions was HCO3− > Cl− > SO42 − > NO3−. All of the investigated groundwaters present two different chemical facies (Ca–HCO3 and Na–HCO3) which is in relation with their interaction with the geological formations of the basin, cation exchange between groundwater
and clay minerals and anthropogenic activities. The principal component analysis (PCA) performed on groundwater identified
three principal components controlling their variability in groundwater. Electrical conductivity, Mg2+, Na+, SO42−, and Cl− content were associated in the same component (PC1) (salinity), determined principally by anthropogenic activities. The pH,
CO32 −, HCO3−, and Ca2+ (PC2) content were related to the geogenic factor. Finally, the NO3−, Cl− and K+ (PC3) were controlled by anthropogenic activity as a consequence of inorganic fertilizers. 相似文献
12.
M. A. Halim R. K. Majumder S. A. Nessa K. Oda Y. Hiroshiro B. B. Saha S. M. Hassain Sk. A. Latif M. A. Islam K. Jinno 《Environmental Geology》2009,58(1):73-84
An integrated study has been carried out to elucidate the distribution and occurrence of arsenic in selected groundwater samples
in the area of Sherajdikhan, Bangladesh. Arsenic and other parameters (T, pH, EC, Na+, K+, Ca2+, Mg2+, Cl−, NO3
−, SO4
2−, HCO3
−, PO4
3−, Fe, Mn and DOC) have been measured in groundwater samples collected from shallow/deep tube wells at different depths. Hydrogeochemical
data suggest that the groundwaters are generally Ca–Mg–HCO3 and Mg–Ca–HCO3 types with bicarbonate (HCO3
−) as the dominant anion, though the other type of water has also been observed. Dissolved arsenic in groundwater ranged from
0.006 to 0.461 mg/l, with 69% groundwater samples exceeded the Bangladesh limit for safe drinking water (0.05 mg/l). Correlation
and principal component analysis have been performed to find out possible relationships among the examined parameters in groundwater.
Low concentrations of NO3
− and SO4
2−, and high concentrations of DOC, HCO3
− and PO4
3− indicate the reducing condition of subsurface aquifer where sediments are deposited with abundant organic matter. Distinct
relationship of As with Fe and Mn, and strong correlation with DOC suggests that the biodegradation of organic matter along
with reductive dissolution of Fe–Mn oxyhydroxides has being considered the dominant process to release As in the aquifers
studied herein. 相似文献
13.
Julien Nikiema Mario Schirmer Walter Gläßer Ronald Krieg 《Environmental Earth Sciences》2010,61(1):11-26
About 24 samples from hand-dug wells and boreholes were used to characterize concentrations of the main inorganic ions in
a laterite environment under semi-arid climatic conditions in Tikaré, northern Burkina Faso. It was found that the most represented
groundwater anion in groundwater was HCO3
− with average levels of 49.1 mg/L in the dry season and 33.5 mg/L in the rainy season. The most represented cation was Ca2+ with mean concentrations of 13.7 and 9.5 mg/L, respectively. The main processes, which influence the concentrations of these
ions, are evaporation (dry season), local enrichment of recharge water in some elements, ion exchange and fixation by clay
minerals (in case of K+). The best correlations were found between Ca2+ and Mg2+ (r = 0.95), Cl− and Na+ (r = 0.95), HCO3
− and Mg2+ (r = 0.89), HCO3
− and Ca2+ (r = 0.89), and between HCO3
− and Na+ (r = 0.80). In general, the quality of the groundwater from the different wells sampled for this study was good enough to serve
as drinking water. However, there were situations where the quality of water was polluted because of anthropogenic contaminants
(mainly NO3
−, K+, Cl−) from septic tanks and manure pits located in the vicinity of some sampled wells. In addition, application of fertilizers
also represents a potential anthropogenic contamination source with regard to SO4
2−, Ca2+, K+, Na+, and Mg2+. Considering the high concentrations of SO4
2−, Mg2+, Na+ and Ca2+ found in one borehole, the deeper, fractured aquifers were also likely to be enriched in these elements. In contrast, the
shallow aquifers are likely to be contaminated with Cl−, NO3
− and K+. Cl− and K+ seem to be locally present in recharge water as shown by their relative higher mean concentrations in the rainy season samples. 相似文献
14.
Intrusions of the Irtysh Complex are spatially restricted to the regional Irtysh Shear Zone (ISZ) and are hosted in blocks
of high-grade metamorphic rocks (Kurchum, Predgornenskii, Sogra, and others) in the greenschist matrix of the ISZ. The massifs
consist of contrasting rock series from gabbro to plagiogranite and granite at strongly subordinate amounts of diorite and
the practical absence of rocks of intermediate composition (tonalite and granodiorite). The complex was produced in the Early
Carboniferous, simultaneously with the onset of the origin of the ISZ itself. The granitoids composing the complex affiliate
with diverse petrochemical series (from subaluminous plagiogranite of the andesite series to granite of the calc-alkaline
series) and contain similar REE and HFSE concentrations [total REE = 103–163 ppm (La/Yb)
n
= 3.59–5.44, Zr (200–273 ppm), Nb (7.6–10.6 ppm), Hf (6.1–7.6 ppm), and Ta (0.68–1.19 ppm)] but are different in concentrations
in LILE [Rb (3–9 and 121–221 ppm), Sr (213–375 and 77–148 ppm), and Ba (67–140 and 240–369 ppm)] and isotopic composition
of Nd (ɛNd(T) from +5.3 in the plagiogranite to −1.2 in the granite) and O (δ18O from +9.4 in the plagiogranite to +14.5 in the granite). Data on the geochemistry and isotopic composition of metamorphic
rocks of the Kurchum block and numerical geochemical simulations indicate that the granitoids were generated via the melting
of a heterogeneous crustal source, which consisted of upper crustal metapelites and metabasites of the oceanic basement of
the blocks of high-grade metamorphic rocks. The differences in the chemical and isotopic compositions of the granitoids were
predetermined by the mixing of variable proportions of granitoid magmas derived from metapelite and metabasite sources. 相似文献
15.
Environmental geochemistry and quality assessment of surface and subsurface water of Mahi River basin, western India 总被引:4,自引:3,他引:1
The hydrogeochemical study of surface and subsurface water of Mahi River basin was undertaken to assess the major ion chemistry,
solute acquisition processes and water quality in relation to domestic and irrigation uses. The analytical results show the
mildly acidic to alkaline nature of water and dominance of Na+ and Ca2+ in cationic and HCO3
− and Cl− in anionic composition. In general, alkaline-earth elements (Ca2+ + Mg2+) exceed alkalis (Na+ + K+) and weak acids (HCO3
−) dominate over strong acids (SO4
2+ + Cl−) in majority of the surface and groundwater samples. Ca2+–Mg2+–HCO3
− is the dominant hydrochemical facies both in surface and groundwater of the area. The weathering of rock-forming minerals
mainly controlled the solute acquisition process with secondary contribution from marine and anthropogenic sources. The higher
concentration of sodium and dissolved silica, high equivalent ratios of (Na+ + K+/TZ+), (Na+ + K+/Cl−) and low ratio of (Ca2+ + Mg2+)/(Na+ + K+) suggest that the chemical composition of the water is largely controlled by silicate weathering with limited contribution
from carbonate weathering and marine and anthropogenic sources. Kaolinite is the possible mineral that is in equilibrium with
the water, implying that the chemistry of river water favors kaolinite formation. Assessment of water samples for drinking
purposes suggests that the majority of the water samples are suitable for drinking. At some sites concentrations of TDS, TH,
F−, NO3
− and Fe are exceeding the desirable limit of drinking. However, these parameters are well within the maximum permissible limit
except for some cases. To assess the suitability for irrigation, parameters like SAR, RSC and %Na were calculated. In general,
both surface and groundwater is of good to suitable category for irrigation uses except at some sites where high values of
salinity, %Na and RSC restrict its uses. 相似文献
16.
Mirza A. T. M. Tanvir Rahman Ratan Kumar Majumder Syed Hafizur Rahman Md. Abdul Halim 《Environmental Earth Sciences》2011,63(2):363-373
Twenty groundwater samples were collected from two different areas in Satkhira Sadar Upazila to identify the source of salinity
in deep groundwater aquifer. Most of the analyzed groundwater is of Na–Cl–HCO3 type water. The trends of anion and cation are Cl− > HCO3
− > NO3
− > SO4
2− and Na+ > Ca2+ > Mg2+ > K+, respectively. Groundwater chemistry in the study area is mainly governed by rock dissolution and ion exchange. The dissolved
minerals in groundwater mainly come from silicate weathering. The salinity of groundwater samples varies from ~1 to ~5%, and
its source is possibly the paleo-brackish water which may be entrapped during past geologic periods. 相似文献
17.
Hydrogeochemical processes in the groundwater environment of Heihe River Basin,northwest China 总被引:5,自引:0,他引:5
Zhu Gaofeng Su Yonghong Huang Chunlin Feng Qi Liu Zhiguang 《Environmental Earth Sciences》2010,60(1):139-153
The Heihe River Basin is a typical arid inland river basin for examining stress on groundwater resources in northwest China.
The basin is composed of large volumes of unconsolidated Quaternary sediments of widely differing grain size, and during the
past half century, rapid socio-economic development has created an increased demand for groundwater resources. Understanding
the hydrogeochemical processes of groundwater and water quality is important for sustainable development and effective management
of groundwater resources in the Heihe River basin. To this end, a total of 30 representative groundwater samples were collected
from different wells to monitor the water chemistry of various ions and its quality for irrigation. Chemical analysis shows
that water presents a large spatial variability of chemical facies (SO4
2−–HCO3−, SO4
2−–Cl−, and Cl−–SO4
2−) as groundwater flow from recharge area to discharge area. The ionic ratio indicates positive correlation between the flowing
pairs of parameters: Cl− and Na+(r = 0.95), SO4
2− and Na+ (r = 0.84), HCO3
− and Mg2+(r = 0.86), and SO4
2− and Ca2+ (r = 0.91). Dissolution of minerals, such as halite, gypsum, dolomite, silicate, and Mirabilite (Na2SO4·10H2O) in the sediments results in the Cl−, SO4
2−, HCO3
−, Na+, Ca2+ and Mg2+ content in the groundwater. Other reactions, such as evaporation, ion exchange, and deposition also influence the water composition.
The suitability of the groundwater for irrigation was assessed based on the US Salinity Laboratory salinity classification
and the Wilcox diagram. The results show that most of the groundwater samples are suitable for irrigation uses barring a few
locations in the dessert region in the northern sub-basin. 相似文献
18.
Mohsen Jalali 《Environmental Geology》2009,56(7):1479-1488
This study was conducted to evaluate factors regulating groundwater quality in an area with agriculture as main use. Thirty
groundwater samples have been collected from Razan area (Hamadan, Iran) for hydrochemical investigations to understand the
sources of dissolved ions and assess the chemical quality of the groundwater. The chemical compositions of the groundwater
are dominated by Na+, Ca2+, HCO3
−, Cl− and SO4
2−, which have been derived largely from natural chemical weathering of carbonate, gypsum and anthropogenic activities of fertilizer’s
source. The production of SO4
2− has multiple origins, mainly from dissolution of sulphate minerals, oxidation of sulphide minerals and anthropogenic sources.
The major anthropogenic components in the groundwater include Na+, Cl−, SO4
2− and NO3
−, with Cl− and NO3
− being the main contributors to groundwater pollution in Razan area. 相似文献
19.
Environmental geochemistry and quality assessment of mine water of Jharia coalfield,India 总被引:1,自引:0,他引:1
Abhay Kumar Singh M. K. Mahato B. Neogi B. K. Tewary A. Sinha 《Environmental Earth Sciences》2012,65(1):49-65
A long mining history and unscientific exploitation of Jharia coalfield caused many environmental problems including water
resource depletion and contamination. A geochemical study of mine water in the Jharia coalfield has been undertaken to assess
its quality and suitability for domestic, industrial and irrigation uses. For this purpose, 92 mine water samples collected
from different mining areas of Jharia coalfield were analysed for pH, electrical conductivity (EC), major cations (Ca2+, Mg2+, Na+, K+), anions (F−, Cl−, HCO3
−, SO4
2−, NO3
−), dissolved silica (H4SiO4) and trace metals. The pH of the analysed mine water samples varied from 6.2 to 8.6, indicating mildly acidic to alkaline
nature. Concentration of TDS varied from 437 to 1,593 mg L−1 and spatial differences in TDS values reflect the variation in lithology, surface activities and hydrological regime prevailing
in the region. SO4
2− and HCO3
− are dominant in the anion and Mg2+ and Ca2+ in the cation chemistry of mine water. High concentrations of SO4
2− in the mine water of the area are attributed to the oxidative weathering of pyrites. Ca–Mg–SO4 and Ca–Mg–HCO3 are the dominant hydrochemical facies. The drinking water quality assessment indicates that number of mine water samples
have high TDS, total hardness and SO4
2− concentrations and needs treatment before its utilization. Concentrations of some trace metals (Fe, Mn, Ni, Pb) were also
found to be above the desirable levels recommended for drinking water. The mine water is good to permissible quality and suitable
for irrigation in most cases. However, higher salinity, residual sodium carbonate and Mg-ratio restrict its suitability for
irrigation at some sites. 相似文献
20.
Factors controlling fluoride contents of groundwater in north-central and northwestern Sri Lanka 总被引:1,自引:0,他引:1
Chemical characterization has been made of groundwater bodies at 294 locations in four village districts in north-central
and northwestern Sri Lanka, with special focus on fluorine contamination. High fluoride contents in groundwater are becoming
a major problem in the dry zone of Sri Lanka, and dental fluorosis and renal failures are widespread. Field measurements of
temperature, pH, and electrical conductivity were made during sampling. Chemical analyses of the water samples were later
made using atomic absorption spectroscopy, spectrophotometry, and titration. Fluoride concentrations in the study area vary
from 0.01 to 4.34 mg/l, and depend on pH and the concentrations of Na, Ca, and HCO3
−. Basement rocks including hornblende biotite gneiss, biotite gneiss, and granitic gneiss seem to have contributed to the
anomalous concentrations of fluoride in the groundwater. Longer residence time in aquifers within fractured crystalline bedrocks
may enhance fluoride levels in the groundwater in these areas. In addition, elevated fluoride concentrations in shallow groundwater
in intensive agricultural areas appear to be related to the leaching of fluoride from soils due to successive irrigation. 相似文献