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1.
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
2.
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
3.
Anwar Zahid M. Qumrul Hassan K.-D. Balke Matthias Flegr David W. Clark 《Environmental Geology》2008,54(6):1247-1260
Dissolved major ions and important heavy metals including total arsenic and iron were measured in groundwater from shallow
(25–33 m) and deep (191–318 m) tube-wells in southeastern Bangladesh. These analyses are intended to help describe geochemical
processes active in the aquifers and the source and release mechanism of arsenic in sediments for the Meghna Floodplain aquifer.
The elevated Cl− and higher proportions of Na+ relative to Ca2+, Mg2+, and K+ in groundwater suggest the influence by a source of Na+ and Cl−. Use of chemical fertilizers may cause higher concentrations of NH4+ and PO43− in shallow well samples. In general, most ions are positively correlated with Cl−, with Na+ showing an especially strong correlation with Cl−, indicating that these ions are derived from the same source of saline waters. The relationship between Cl−/HCO3− ratios and Cl− also shows mixing of fresh groundwater and seawater. Concentrations of dissolved HCO3− reflect the degree of water–rock interaction in groundwater systems and integrated microbial degradation of organic matter.
Mn and Fe-oxyhydroxides are prominent in the clayey subsurface sediment and well known to be strong adsorbents of heavy metals
including arsenic. All five shallow well samples had high arsenic concentration that exceeded WHO recommended limit for drinking
water. Very low concentrations of SO42− and NO3− and high concentrations of dissolved Fe and PO43− and NH4+ ions support the reducing condition of subsurface aquifer. Arsenic concentrations demonstrate negative co-relation with the
concentrations of SO42− and NO3− but correlate weakly with Mo, Fe concentrations and positively with those of P, PO43− and NH4+ ions. 相似文献
4.
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
5.
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
6.
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
7.
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
8.
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
9.
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
10.
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
11.
This study assessed the levels of selected inorganic contaminants in streams and stream sediments in the effluent areas relating
to the pyrometallurgical and hydrometallurgical treatment of gold ores in the Obuasi gold mine, Ghana. Water and stream sediment
samples were taken from specific locations during the consecutive rainy and dry seasons, and concentrations of phosphate (PO4
3−), nitrate (NO3
−), chloride (Cl−), sulphate (SO4
2−), sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), arsenic (As), copper (Cu), iron (Fe), zinc (Zn) and lead (Pb), were determined. Alkalinity, pH, temperature and specific
electrical conductivity were also measured. In the water samples, the average pH range for both the seasons is 6.9–7.4, most
anions and metals have relatively higher concentrations in the wet season than in the dry season at both the metallurgical
sites. Trace metals concentrations were comparatively low (<0.01–5.00 mg/l), higher in the dry season at the pyrometallurgical
sites. Irrespective of seasons, SO4
2− (0.80–949.50 mg/l) and PO4
3− (<0.01–6.30 mg/l) were pronounced at the pyrometallurgical sites, while NO3
− (0.01–98.45 mg/l) and Cl− (1.88-49.05 mg/l) were higher at the hydrometallurgical sites. In water samples, Ca2+ and SO4
2+ were the dominant cation and anion, respectively. In the stream sediments, except pH, NO3
−, Cl−, Na+ and Mg2+, all other parameter values were relatively higher at the hydrometallurgical areas. The average concentrations of Ca2+, Mg2+, As and Fe are remarkably high at both metallurgical sites (3,217–46,026 mg/kg). Overall, the level of parameters in the
water samples are pronounced at pyrometallurgical sites, whereas the levels in sediments are higher at the hydrometallurgical
sites. 相似文献
12.
The purpose of this study is to investigate the quality and usage possibility of groundwater in the Çavuşçayı basin and suggest the best water structure for the groundwater use. Results from hydrochemical analyses reveal that groundwater is mostly affected by salty (Na+–Cl−) waters of the Incik Formation and brackish (Ca2+, Mg2+–SO
4
2−
) waters of the Bayındır Formation. The Alibaba saltpan discharged (2 l/s) from the Incik Formation is used for salt production. In the basin, salinity risk increases with depth and along the groundwater flow direction. Therefore, shallow water and trenches opened in the alluvium aquifer at the east of the basin were determined to yield suitable water with no Na+ and Cl− contamination. Following the heavy rainy period, waters of less salinity and conductivity are possibly used for agriculture. 相似文献
13.
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
14.
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
15.
Hydrogeochemical investigations and groundwater provinces of the Friuli Venezia Giulia Plain aquifers,northeastern Italy 总被引:2,自引:0,他引:2
Water resources are a key factor, particularly for the planning of the sustainable regional development of agriculture, as
well as for socio-economic development in general. A hydrochemical investigation was conducted in the Friuli Venezia Giulia
aquifer systems to identify groundwater evolution, recharge and extent of pollution. Temperature, pH, electric conductivity,
total dissolved solids, alkalinity, total hardness, SAR, Ca2+, Na+, K+, Mg2+, Cl−, SO4
2−, NO3
−, HCO3
−
, water quality and type, saturation indexes and the environmental stable isotope δ18O were determined in 149 sampling stations. The pattern of geochemical and oxygen stable isotope variations suggests that
the sub-surface groundwater (from phreatic and shallow confined aquifers) is being recharged by modern precipitations and
local river infiltrations. Four hydrogeological provinces have been recognised and mapped in the Friuli Venezia Giulia Plain
having similar geochemical signatures. These provinces have different degrees of vulnerability to contamination. The deep
confined groundwater samples are significantly less impacted by surface activities; and it appears that these important water
resources have very low recharge rates and would, therefore, be severely impacted by overabstraction. 相似文献
16.
Hydrochemical characteristics and quality assessment of shallow groundwater in a coastal area of Southwest Bangladesh 总被引:4,自引:3,他引:1
In this study, the hydrochemical characteristics of shallow groundwater in a coastal region (Khulna) of southwest Bangladesh
have been evaluated based on different indices for drinking and irrigation uses. Water samples were collected from 26 boreholes
and analyzed for major cations and anions. Other physico-chemical parameters like pH, electrical conductivity (EC), and total
dissolved solids were also measured. Most groundwater is slightly alkaline and largely varies in chemical composition, e.g.
EC ranges from 962 to 9,370 μs/cm. The abundance of the major ions is as follows: Na+ > Ca2+ > Mg2+ > K+ = Cl− > HCO3
− > SO4
2− > NO3
−. Interpretation of analytical data shows two major hydrochemical facies (Na+–K+–Cl−–SO4
2− and Na+–K+–HCO3
−) in the study area. Salinity, total hardness, and sodium percentage (Na%) indicate that most of the groundwater samples are
not suitable for irrigation as well as for domestic purposes and far from drinking water standard. Results suggest that the
brackish nature in most of the groundwaters is due to the seawater influence and hydrogeochemical processes. 相似文献
17.
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
18.
Statistical analysis of groundwater chemistry of the Tarim River lower reaches,Northwest China 总被引:2,自引:2,他引:0
Jianhua Xu Yaning Chen Weihong Li Lijun Zhang Yulian Hong Xueli Bi Yang Yang 《Environmental Earth Sciences》2012,65(6):1807-1820
This study applied a comprehensive quantitative approach including statistical, principal component and gray relation analyses
to assess the groundwater chemistry based on monitored data from 840 samples collected from the lower reaches of Tarim River
from 2000 to 2009. The main findings were: (1) there were six types of groundwater chemistry in the lower reaches of Tarim
River where Cl·SO4–Na·Mg was the dominant type accounting for 73.57% in all samples. There were linear relationships among chemical parameters,
where TDS had significant multiple correlations with Na+, K+, Mg2+, Ca2+ and Cl−, respectively. (2) Three principal components (PC1, PC2 and PC3) were extracted. They included comprehensive measurements
for salinization, alkalinity and pH, respectively. Most parameters showed decreasing trends during the period of 2000–2009,
as well as the scores on PC1, because the concentrations of various chemical substances were diluted due to the uplift of
the groundwater table in the lower reaches and the implementation of the ecological water delivery project in 2000. (3) HCO3
− was the most sensitive chemical parameter affected by the groundwater table followed by TA, Mg2+, TH, SO42−, K+, TDS and TS. PC2 was the most sensitive principal component to the change of the groundwater table followed by PC1 and PC3. 相似文献
19.
A. G. S. Reddy 《Environmental Earth Sciences》2014,71(10):4473-4495
Hydrogeochemical controlling factors for high rate of groundwater contamination in stressed aquifer of fractured, consolidated rocks belonging to semi-arid watershed are examined. The groundwater in mid-eastern part of Prakasam district confining to Musi-Gundlakamma sub-basins is heavily contaminated with nitrate and fluoride. Distinct water chemistry is noticed among each group of samples segregated based on concentration of these contaminants. The nitrate is as high as 594 mg/l and 57 % of the samples have it in toxic level as per BIS drinking water standards, so also the fluoride which has reached a maximum of 8.96 mq/l and 43 % of samples are not fit for human consumption. Nitrate contamination is high in shallow aquifers and granitic terrains, whereas fluoride is in excess concentration in deeper zones and meta-sediments among the tested wells, and 25 % of samples suffer from both NO3 ? and F? contamination. Na+ among cations and HCO3 ? among anions are the dominant species followed by Mg2+ and Cl?. The NO3 ?-rich groundwater is of Ca2+–Mg2+–HCO3 ?, Ca2+–Mg2+–Cl? and Na+–HCO3 ? type. The F?-rich groundwater is dominantly of Na+–HCO3 ? type and few are of Na+–SO4 2? type, whereas the safe waters (without any contaminants) are of Ca2+–Mg2+–HCO3 ?– and Na+–HCO3 ? types. High molecular percentage of Na+, Cl?, SO4 2? and K? in NO3 ? rich groundwater indicates simultaneous contribution of many elements through domestic sewerage and agriculture activity. It is further confirmed by analogous ratios of commonly associated ions viz NO3 ?:Cl?:SO4 2? and NO3 ?:K+:Cl? which are 22:56:22 and 42:10:48, respectively. The F? rich groundwater is unique by having higher content of Na+ (183 %) and HCO3 ? (28 %) than safe waters. The K+:F?:Ca2+ ratio of 10:5:85 and K+:F?: SO4 2? of 16:7:77 support lithological origin of F? facilitated by precipitation of CaCO3 which removes Ca2+ from solution. The high concentrations of Na+, CO3 ? and HCO3 ? in these waters act as catalyst allowing more fluorite to dissolve into the groundwater. The indices, ratios and scatter plots indicate that the NO3 ? rich groundwater has evolved through silicate weathering-anthropogenic activity-evapotranspiration processes, whereas F? rich groundwater attained its unique chemistry from mineral dissolution-water–rock interaction-ion exchange. Both the waters are subjected to external infusion of certain elements such as Na+, Cl?, NO3 ? which are further aggravated by evaporation processes leading to heavy accumulation of contaminants by raising the water density. Presence of NO3 ? rich samples within F? rich groundwater Group and vice versa authenticates the proposed evolution processes. 相似文献
20.
Mingming Jing Wei Chen Tingting Zheng Yuan Liao Julia Ellis Burnet Min Xu Chen Yang Lina Shen Mingzhong Liang 《Environmental Earth Sciences》2011,64(4):1051-1058
This paper reports original data on the physical and chemical parameters of precipitation, river water and groundwater in
and around the Longhushan Nature Reserve Area, located in southwestern China karst region, and provides a preliminary characterization
of the hydrogeochemical process governing the natural water evolution in this area. The rainfall and river water mainly pertain
to the HCO3
−–Ca2+ type and groundwater mainly pertain to the HCO3
−–Ca2+ + Mg2+ type. The HCO3
− was the predominant anion and Ca2+ was the predominant cation in all waters, respectively. The Gibbs Boomerang Envelop model, the 1:1 relationship of Na+ plus K+ versus Cl− as well as the 1:1 relationship of Ca2+ plus Mg2+ versus HCO3
− all suggested geochemical weathering is the main controlling factor for the geochemical compositions of this natural water.
In surface water, the Mg2+/Ca2+ ratios ranged from 0.32 to 0.42 and the Na+/Ca2+ varied between 0.04 and 0.05. In the groundwater, the Mg2+/Ca2+ ratios varied from 0.37 to 0.62 and were below the ideal ratio of 0.8. These ratios showed the presence of a dolomite source.
Analysis of trace elements showed that As, B, Pb, Se, Sr, V and Zn elements were abundant in the natural water during summer
in this region. 相似文献