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1.
Response of groundwater chemistry to water deliveries in the lower reaches of Tarim River,Northwest China 总被引:2,自引:0,他引:2
Yongjin Chen Kefa Zhou Yaning Chen Weihong Li Jiazhen Liu Tao Wang 《Environmental Geology》2008,53(6):1365-1373
In this paper, we analysed the monitored data from nine groundwater-monitoring transects in the lower reaches of Tarim River
during the five times of stream water deliveries to the river transect where the stream flow ceased. The results showed that
the groundwater depth in the lower reaches of Tarim River rose from −9.30 m before the conveyances to −8.17 and −6.50 m after
the first and second conveyances, −5.81 and −6.00 m after the third and fourth the conveyance, and −4.73 m after the fifth.
The horizontal extent of groundwater recharge was gradually enlarged along both sides of the channel of conveyance, i.e.,
from 250 m in width after the first conveyance to 1,050 m away from the channel after the fourth delivery. With the rising
groundwater level, the concentrations of major anions Cl−, SO42− and cations Ca2+, Mg2+, Na+, as well as total dissolved solids (TDS) in groundwater underwent a significant change. The spatial variations in groundwater
chemistry indicated that the groundwater chemistry at the transect near Daxihaizi Reservoir changed earlier than that farther
from it. In the same transect, the chemical variations were earlier in the monitoring well close to watercourse than that
farther away from the stream. In general, the concentration of the major ions and TDS at each monitoring well increased remarkably
when the water delivery started, and decreased with the continued water delivery, and then increased once again at the end
of the study period. Hence, the whole study period may be divided into three stages: the initial stage, the intermediate stage
and the later stage. According to the three stages of groundwater chemistry reaction to water delivery and the relationships
between groundwater chemical properties and groundwater depths, we educe that under the situation of water delivery, the optimum
groundwater depth in the lower reaches of the Tarim River should be −5 m. 相似文献
2.
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
3.
N. Subba Rao Deepali Marghade A. Dinakar I. Chandana B. Sunitha B. Ravindra T. Balaji 《Environmental Earth Sciences》2017,76(21):747
A survey on quality of groundwater was carried out for assessing the geochemical characteristics and controlling factors of chemical composition of groundwater in a part of Guntur district, Andhra Pradesh, India, where the area is underlain by Peninsular Gneissic Complex. The results of the groundwater chemistry show a variation in pH, EC, TDS, Ca2+, Mg2+, Na+, K+, HCO3 ?, Cl?, SO4 2?, NO3 ? and F?. The chemical composition of groundwater is mainly characterized by Na+?HCO3 ? facies. Hydrogeochemical type transits from Na+–Cl?–HCO3 ? to Na+–HCO3 ?–Cl? along the flow path. Graphical and binary diagrams, correlation coefficients and saturation indices clearly explain that the chemical composition of groundwater is mainly controlled by geogenic processes (rock weathering, mineral dissolution, ion exchange and evaporation) and anthropogenic sources (irrigation return flow, wastewater, agrochemicals and constructional activities). The principal component (PC) analysis transforms the chemical variables into four PCs, which account for 87% of the total variance of the groundwater chemistry. The PC I has high positive loadings of pH, HCO3 ?, NO3 ?, K+, Mg2+ and F?, attributing to mineral weathering and dissolution, and agrochemicals (nitrogen, phosphate and potash fertilizers). The PC II loadings are highly positive for Na+, TDS, Cl? and F?, representing the rock weathering, mineral dissolution, ion exchange, evaporation, irrigation return flow and phosphate fertilizers. The PC III shows high loading of Ca2+, which is caused by mineral weathering and dissolution, and constructional activities. The PC IV has high positive loading of Mg2+ and SO4 2?, measuring the mineral weathering and dissolution, and soil amendments. The spatial distribution of PC scores explains that the geogenic processes are the primary contributors and man-made activities are the secondary factors responsible for modifications of groundwater chemistry. Further, geochemical modeling of groundwater also clearly confirms the water–rock interactions with respect to the phases of calcite, dolomite, fluorite, halite, gypsum, K-feldspar, albite and CO2, which are the prime factors controlling the chemistry of groundwater, while the rate of reaction and intensity are influenced by climate and anthropogenic activities. The study helps as baseline information to assess the sources of factors controlling the chemical composition of groundwater and also in enhancing the groundwater quality management. 相似文献
4.
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
5.
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
6.
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
7.
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
8.
N. Subba Rao G. Vidyasagar P. Surya Rao P. Bhanumurthy 《Journal of the Geological Society of India》2014,84(4):494-500
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
9.
Hydrogeochemical investigations are carried out in the different blocks of Burdwan district, West Bengal, India in order to
assess its suitability for drinking as well as irrigation water purpose. Altogether 49 representative groundwater samples
are collected from bore wells and the water chemistry of various ions viz. Ca2+, Mg2+, Na+, K+, CO32−, HCO3−, Cl−, SO42− and NO3− are carried out. The chemical relationships in Piper and Gibbs diagram suggest that the groundwater mainly belongs to alkali
type and Cl− group and are controlled by rock dominance. A comparison of groundwater quality in relation to drinking water quality standards
proves that most of the water samples are suitable for drinking water purpose whereas groundwater in some areas of the district
has high salinity and high sodium adsorption ratio (SAR), indicating unsuitability for irrigation water and needs adequate
drainage. 相似文献
10.
Geochemistry of groundwater,Markandeya River Basin,Belgaum district,Karnataka State,India 总被引:1,自引:0,他引:1
The Markandeya River Basin stretches geographically from 15o56′ to 16o08′ N latitude and 74o37′ to 74o58′ E longitude, positioned in the midst of Belgaum district, in the northern part of Karnataka. The groundwater quality of 54 pre-monsoon samples in the Markandeya River Basin was evaluated for its suitability for drinking and irrigation purposes by estimating pH, EC, TDS, hardness and alkalinity besides major cations (Na+, K+, Ca2+, Mg2+) and anions (HCO3–, Cl–, SO42–, PO43-, F-, NO3–), boron, SAR, % Na, RSC, RSBC, chlorinity index, SSP, non-carbonate hardness, Potential Salinity, Permeability Index, Kelley’s ratio, Magnesium hazard and Index of Base Exchange. Negative Index of Base Exchange indicates the chloro-alkaline disequilibrium in the study area and the majority of water samples fall in the rock dominance field based on Gibbs’ ratio. Permeability indices of classes I and II suggest suitability of groundwater for irrigation. Based on Cl, SO4, HCO3 concentrations, water samples can be classified as normal chloride (96.3%) and normal sulfate (94.4%) and normal bicarbonate (44.4%) water types. 相似文献
11.
Seasonal variation of groundwater quality in a part of Guntur District, Andhra Pradesh, India 总被引:3,自引:0,他引:3
N. Subba Rao 《Environmental Geology》2006,49(3):413-429
The area in Guntur district, Andhra Pradesh, India, is selected to discuss the impact of seasonal variation of groundwater
quality on irrigation and human health, where the agriculture is the main livelihood of rural people and the groundwater is
the main source for irrigation and drinking. Granite gneisses associated with schists and charnockites of the Precambrian
Eastern Ghats underlie the area. Groundwater samples collected seasonally, pre- and post-monsoons, during three years from
forty wells in the area were analyzed for pH, EC, TDS, TA, TH, Ca2+, Mg2+, Na+, K+, CO32−, HCO3−, Cl−, SO42−, NO3−and F−. The chemical relationships in Piper’s diagram, Chebotarev’s genetic classification and Gibbs’s diagram suggest that the
groundwaters mainly belong to non-carbonate alkali type and Cl− group, and are controlled by evaporation-dominance, respectively, due to the influence of semi-arid climate, gentle slope,
sluggish drainage conditions, greater water–rock 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,
especially in post-monsoon period. 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 in post-monsoon compared to that in pre-monsoon. These conditions are caused due to leaching of salts from the
overlying materials by infiltrating recharge waters. A management plan is suggested for sustainable development of the area. 相似文献
12.
National scale evaluation of groundwater chemistry in Korea coastal aquifers: evidences of seawater intrusion 总被引:3,自引:2,他引:1
Youngyun Park Jin-Yong Lee Jeong-Hee Kim Sung-Ho Song 《Environmental Earth Sciences》2012,66(3):707-718
Pollution of groundwater by seawater intrusion poses a threat to sustainable agriculture in the coastal areas of Korea. Therefore, seawater intrusion monitoring stations were installed in eastern, western, and southern coastal areas and have been operated since 1998. In this study, groundwater chemistry data obtained from the seawater intrusion monitoring stations during the period from 2007 to 2009 were analyzed and evaluated. Groundwater was classified into fresh (<1,500 μS/cm), brackish (1,500–3,000 μS/cm), and saline (>3,000 μS/cm) according to EC levels. Among groundwater samples (n = 233), 56, 7, and 37% were classified as the fresh, brackish, and saline, respectively. The major dissolved components of the brackish and saline groundwaters were enriched compared with those of the fresh groundwater. The enrichment of Na+ and Cl− was especially noticeable due to seawater intrusion. Thus, the brackish and saline groundwaters were classified as Ca–Cl and Na–Cl types, while the fresh groundwater was classified as Na–HCO3 and Ca–HCO3 types. The groundwater included in the Na–Cl types indicated the effects of seawater mixing. Ca2+, Mg2+, Na+, K+, SO4 2−, and Br− showed good correlations with Cl− of over r = 0.624. Of these components, the strong correlations of Mg2+, SO4 2−, and Br− with Cl− (r ≥ 0.823) indicated a distinct mixing between fresh groundwater and seawater. The Ca/Cl and HCO3/Cl ratios of the groundwaters gradually decreased and approached those of seawater. The Mg/Cl, Na/Cl, K/Cl, SO4/Cl, and Br/Cl ratios of the groundwaters gradually decreased, and were similar to or lower than those of seawater, indicating that Mg2+, Na+, K+, SO4 2−, and Br−, as well as Cl− in the saline groundwater can be enriched by seawater mixing, while Ca2+ and HCO3 − are mainly released by weathering processes. The influence of seawater intrusion was evaluated using threshold values of Cl− and Br−, which were estimated as 80.5 and 0.54 mg/L, respectively. According to these criteria, 41–50% of the groundwaters were affected by seawater mixing. 相似文献
13.
Environmental research of groundwater in the urban and suburban areas of Attica region,Greece 总被引:4,自引:0,他引:4
G. D. Bathrellos H. D. Skilodimou A. Kelepertsis D. Alexakis I. Chrisanthaki D. Archonti 《Environmental Geology》2008,56(1):11-18
In this study, 92 groundwater samples were collected from the Attica region (Greece). Moreover, geographical information system
database, geochemistry of groundwater samples and statistics were applied. These were used for studying the chemical parameters
(NO3
−, Mg2+, Ca2+, Cl−, and Na+) and conductivity spatial distribution and for assessing their environmental impact. The ranges of chemical parameters of
the water samples (in mg L−1) are: NO3
− 1–306, Mg2+ 2–293, Ca2+ 3–453, Cl− 5–1,988, and Na+ 4–475. The elevated concentrations of sodium, Mg2+, Cl− are attributed to natural contamination (seawater intrusion). On the other hand, NO3
− elevated concentrations are attributed to anthropogenic contamination (nitrate fertilizers). The results of the GIS analysis
showed that elevated values of Na+, Mg2+, Cl− are related to shrubby and sparsely vegetated areas, while elevated values of NO3
− are connected with urban and agricultural areas. 相似文献
14.
Our ability to adapt to changes in groundwater quality, arising from a changing climate and/or local pressures, is dependent on comprehension of the governing controls of spatial variation in groundwater chemistry. This paper presents results of an assessment of dominant hydro-geochemical processes controlling groundwater chemical composition, using an integrated application of hierarchical cluster analysis (HCA) and principal component analysis (PCA) of a major ion dataset of groundwater from lower Shire River valley, Malawi. The area is in the southernmost part of the western section of the East African Rift System (EARS) and has localised occurrence of saline groundwater. HCA classified samples into three main clusters (C1-C3) according to their dominant chemical composition: C1 (dominant composition: Na-Cl; median TDS: 3436 mg L−1), C2 (dominant composition: Na-HCO3; median TDS: 966 mg L−1) and C3 (dominant composition: alkali earths-HCO3; median TDS: 528 mg L−1). These clusters were in turn described by the principal components PC1, PC3 and PC2, respectively, resulting from the PCA. The results of the PCA and geochemical interpretation suggest that the spatial variation of groundwater quality in the area is influenced by the following processes: C3 samples result mainly from H2CO3 weathering of aluminosilicate minerals by percolating water supersaturated with CO2. In addition to aluminosilicate weathering, C2 samples are influenced by the processes of cation exchange of Ca2+ and Mg2+ in the water for Na+ on clay minerals, and carbonate precipitation. The increase in ionic strength of C2 samples is attributed to mixing with high TDS groundwater in proximity with C2 samples. The saline/brackish C1 groundwater results from the processes of evaporation (for samples with high water table close to the Shire marshes) and dissolution of Cl− and SO4-evaporative salts followed by mineralised seep from sedimentary Karoo and Cretaceous Lupata sandstones. 相似文献
15.
Surface and groundwater quality characterization of Deoria District,Ganga Plain,India 总被引:5,自引:5,他引:0
A water quality investigation was carried out in the Deoria district, Ganga plain, to assess the suitability of surface and
groundwaters for domestic, agricultural, and industrial purposes. As much as 50 representative samples from river and groundwater
were collected from various stations to monitor the water chemistry of various ions, comprising Ca2+, Mg2+, Na+, K+, HCO3
−, SO4
2−, NO3
−, Cl−, F−, and trace metals, such as Fe, Cu, Mn, Zn, Cd, and Pb. The results showed that electrical conductance (EC), total dissolved
solids (TDS), HCO3
−, Mg2+, Na+, and total hardness (TH) are above the maximum desirable limit, and apart from Fe and Mn all other trace metals are within
the maximum permissible limit for drinking water. The calculated values for sodium absorption ratio (SAR), salinity, residual
sodium carbonate (RSC), and permeability index (PI) indicate well to permissible use of water for irrigation. High values
of Na%, RSC, and Mg-hazard (MH) at some stations restrict its use for agricultural purpose. Anthropogenic activities affect
the spatial variation of water quality. Economic and social developments of the study area is closely associated with the
characteristics of the hydrological network. 相似文献
16.
Groundwater depletion and quality deterioration due to environmental impacts in Maheshwaram watershed of R.R. district,AP (India) 总被引:3,自引:2,他引:1
Maheshwaram watershed is situated in Ranga Reddy district of Andhra Pradesh at a distance of about 30 km south of Hyderabad,
capital of Andhra Pradesh. The watershed has an area of 60 km2 and has hard rock aquifers with semi-arid climate. The study area has been expanding at a fast pace and now has the distinction
of being one of the fastest growing urban centers facing the problem of groundwater depletion and quality deterioration due
to the absence of perennial source of surface water and also due to over exploitation. Human activities involving industrial
and agricultural development and the inadequate management of land and water resources have, directly or indirectly resulted
in the degradation of environment viz. water and soil. In the present study chemical analysis of groundwater samples of the
study area, collected during pre- and post-monsoon seasons of 2007–2008 has been carried out. The analyzed data are utilized
to characterize the hydro chemical process dominant in the area. Various classification methods such as Piper, Back and Hanshaw,
Wilcox, USA. Salinity Laboratory are employed to critically study the geochemical characteristics of groundwater of the study
area. Finally, principal component analysis (PCA) is also employed to the chemical variables of groundwater to characterize
the hydro chemical process that is dominant in the area. In the analysis four principal components emerged as significant
contributors to the groundwater quality. The total contribution of these four components is about 85–87%. The contribution
of the first component is about 49–50% and has significant positive loadings of Ca2+, Mg2+, Na+, and Cl− ions. The second, third, and fourth principal components have significant positive loadings of F−, NO3
−, SO4
2+, and HCO3
− ions. 相似文献
17.
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
18.
S. Srinivasa Gowd 《Environmental Geology》2005,48(6):702-712
In India, the quantity and quality of water available for irrigation is variable from place to place. Assessment of water
quality has been carried out to determine the sources of dissolved ions in groundwater. Quality of groundwater in a 398 km2 Peddavanka watershed of a semi-arid region of south India is evaluated for its suitability for drinking and irrigation purposes.
The middle Proterozoic Cuddapah Supergroup and Kurnool Group of rocks underlie most of the watershed. The main lithologic
units consist chiefly of quartzite, limestone, and shale. Seventy-six water samples were collected from open-wells and bore-holes.
Water samples were collected representative of the post-monsoon (winter) and pre-monsoon (summer). The quality assessment
is made through the estimation of Ca2+, Mg2+, Na+, K+, Cl−, SO42−, CO32−, HCO3−, total hardness as CaCO3, TDS, EC, and pH. Based on these analyses, parameters like sodium adsorption ratio, % sodium, residual sodium carbonate,
non-carbonate hardness, potential salinity, Kelley’s ratio, magnesium ratio, index of base exchange and permeability index
were calculated. According to Gibbs‘ ratio samples in both seasons fall in the rock dominance field. The overall quality of
waters in the study area in post-monsoon season is high for all constituents ruling out pollution from extraneous sources. 相似文献
19.
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
20.
Environmental significance of snowpit chemistry in the typical monsoonal temperate glacier region,Baishui glacier no. 1, Mt Yulong,China 总被引:1,自引:0,他引:1
Li Zongxing He Yuanqing Pang Hongxi Wilfred H. Theakstone Zhang Ningning He Xianzhong Wang Shijing Pu Tao Du Jiankuo 《Environmental Geology》2009,58(6):1319-1328
Samples were collected from two snowpits in Baishui glacier no. 1, Mt Yulong, China, in May 2006. Snowpit chemistry was studied,
using ion tracer techniques, HYSPLIT model, factor analysis, correlation and trend analysis. It indicated that total cation
concentration is higher in 4,900-m snowpit than in 4,750-m snowpit, whereas total anion concentration is higher in 4,750-m
snowpit. Cations, especially Ca2+, dominate ionic concentrations in Baishui glacier no. 1. According to correlation analysis and factor analysis, ions can
be categorized as follows: Cl− and NO3
− as Group 1, SO4
2− as Group 2, Mg2+ and Ca2+ as Group 3, Na+ as Group 4, K+ as Group 5. Contribution made by terrestrial dust to ionic concentration accounts for 52.27, 100, 99.36, 98.91, 96.16 and
99.97% of Cl−, NO3
−, SO4
2−, K+, Mg2+ and Ca2+, respectively, in 4,900-m snowpit, and for 64.00, 100, 99.57, 98.63, 96.25 and 99.97% in 4,750-m snowpit. Local dust is the
principal source of snowpit chemical components. Pollutants brought from industrial areas of South Asia, Southeast Asia and
South China by monsoonal circulation also makes some contribution to anion concentrations, but pollution associated with human
activities makes a very slight contribution in study area. The chemical characteristics of two snowpits are different owing
to the difference of deposition mechanism and local environment in different altitudes. 相似文献