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1.
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
2.
The degradation of groundwater quality, which has been noted in the recent years, is closely connected to the intensification
of agriculture, the unreasonable use of chemical fertilizers and the excess consumption of large volumes of irrigation water.
In the hilly region of central Thessaly in Greece, which suffers the consequences of intense agricultural use, a hydrogeological
study is carried out, taking groundwater samples from springs and boreholes in the Neogene aquifers. The aim of this study
is the investigation of irrigation management, water quality and suitability for various uses (water supply, irrigation),
the degradation degree and the spatial distribution of pollutants using GIS. The following hydrochemical types prevail in
the groundwater of the study area: Ca–Mg–HCO3, Mg–Ca–Na–HCO3 and Na–HCO3. In the above shallow aquifers, especially high values of NO3
− (31.7–299.0), NH4
+ (0.12–1.11), NO2
− (0.018–0.109), PO4
3− (0.07–0.55), SO4
2− (47.5–146.5) and Cl− (24.8–146.5) are found, particularly near inhabited areas (values are in mg L−1). The water of shallow aquifers is considered unsuitable for human use due to their high polluting load, while the water
of the deeper aquifers is suitable for human consumption. Regarding water suitability for irrigation, the evaluation of SAR
(0.153–7.397) and EC (481–1,680 μS cm−1) resulted in classification category ‘C3S1’, indicating high salinity and low sodium water which can be used for irrigation
in most soils and crops with little to medium danger of development of exchangeable sodium and salinity. The statistical data
analysis, the factor analysis and the GIS application have brought out the vulnerable-problematic zones in chemical compounds
of nitrogen and phosphates. The groundwater quality degradation is localized and related exclusively to human activities.
Based on 2005 and 2008 estimates, the annual safe yield of the region’s aquifers were nearly 41.95 MCM. However, the existing
situation is that 6.37 MCM of water is over extracted from these aquifers. 相似文献
3.
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
4.
Bruce Banoeng-Yakubo Sandow Mark Yidana Nti Emmanuel Thomas Akabzaa Daniel Asiedu 《Environmental Earth Sciences》2009,59(4):867-879
Conventional graphical and statistical methods were used with water quality indices to characterize the hydrochemistry of
groundwater from the northern part of the Volta region of Ghana. The objective was to determine the processes that affect
the hydrochemistry and the variation of these processes in space among the three main geological terrains: the Buem formation,
Voltaian System and the Togo series that underlie the area, and to determine the suitability of groundwater from the area
for drinking purposes. The Q-mode cluster analysis reveals three main water groups. The groups established from the Q-mode
HCA appear to indicate different degrees of weathering which could further indicate varying levels of fracturing aquifer hydraulic
properties. R-mode HCA and factor analysis (using varimax rotation and Kaiser Criterion) were then applied to determine the
significant sources of variation in the hydrochemistry. This study finds that groundwater hydrochemistry in the area is controlled
by the weathering of silicate and carbonate minerals, as well as the chemistry of infiltrating precipitation. Mineral activity
diagrams for the CaO–Na2O–Al2O3–SiO2–H2O and CaO–MgO–Al2O3–SiO2–H2O systems plotted for the area indicate stability in the smectite field and attribute hydrochemistry to the weathering of
silicate minerals. Silicate mineral weathering and the effects of precipitation appear to be pervasive among all the three
main geological terrains, whereas carbonate weathering is localized among the Voltaian aquifers. Cation exchange does not
appear to play a significant role in the hydrochemistry but mild Water quality indices (WQI) were calculated for the samples
using the concentrations of Na+, Ca2+, Mg2+, Cl−, NO3
−, F−, and EC at the various sample locations. The WQI values indicate that groundwater from the study area is of excellent quality
for drinking purposes. WQI values from groundwater samples are averagely higher than samples taken from surface water sources
in the area. This implies that geology has had an impact on the WQI of groundwater in the area. 相似文献
5.
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
6.
Study on geochemistry of groundwater occurring at different depths is rarely attempted due to inherent difficulties in sample isolation and lack of significant species variations. Three-dimensional (spatial, temporal and depth-wise) evaluation of water chemistry variations would give holistic picture of aquatic chemistry. In order to fill the knowledge gap the vertical hydrogeochemistry of Penna-Chitravati inter-stream sub-basin is studied.Water samples are segregated into different groups based on water levels of source wells. The group samples pertaining to granite terrain (A to C) does not show much variation for tested parameters as most of the samples fall within 20m water level. In shale aquifers groundwater is progressively less ionized as depth to levels increases (Group D to G). Reduction of EC and Na-Cl along with falling water levels indicates deeper aquifers are free from contamination. Gradual decrease in HCO 3 - with depth substantiates that deeper aquifers are getting less fresh water due to lack of inter connectivity in shale formations. Sodium in groundwater of both the granite and shale aquifers is contributed by weathering of silicate rocks as the Na+/Cl- molar ratio is >1 in many samples. Majority of the samples in both the geological terrains have Ca2+/Mg2+ ratio between 1 to < 2 indicating dolomite dissolution is responsible for Ca2+-Mg2+ contribution. The chemistry of tested water indicate aquifer matrix is responsible for chemical make-up of pore water which was obliterated due to extraneous sources like anthropogenic contamination as Na+, Cl-, NO 3 - and SO 4 2- /HCO 3 - is high in many samples belonging to shallow aquifers. Thermodynamic action in deep aquifers could be responsible for dissimilar water chemistry in aquifers belonging to same geological domain. 相似文献
7.
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
8.
Anuar Sefie Ahmad Zaharin Aris Mohammad Firuz Ramli Tahoora Sheikhy Narany Mohd Khairul Nizar Shamsuddin Syaiful Bahren Saadudin Munirah Abdul Zali 《Environmental Earth Sciences》2018,77(10):397
Continual expansion of population density, urbanization, agriculture, and industry in most parts of the world has increased the generation of pollution, which contributes to the deterioration of surface water quality. This causes the dependence on groundwater sources for their daily needs to accumulate day by day, which raises concerns about their quality and hydrogeochemistry. This study was carried out to increase understanding of the geological setup and assess the groundwater hydrogeochemical characteristics of the multilayered aquifers in Lower Kelantan Basin. Based on lithological data correlation of exploration wells, the study area can be divided into three main aquifers: shallow, intermediate and deep aquifers. From these three aquifers, 101 groundwater samples were collected and analyzed for various parameters. The results showed that pH values in the shallow, intermediate and deep aquifers were generally acidic to slightly alkaline. The sequences of major cations and anions were Na+ > Ca2+ > Mg2+ > K+ and HCO3? > Cl? > SO42? > CO32?, respectively. In the intermediate aquifer, the influence of ancient seawater was the primary factor that contributed to the elevated values of electrical conductivity (EC), Cl? and total dissolved solids (TDS). The main facies in the shallow aquifer were Ca–HCO3 and Na–HCO3 water types. The water types were dominated by Na–Cl and Na–HCO3 in the intermediate aquifer and by Na–HCO3 in the deep aquifer. The Gibbs diagram reveals that the majority of groundwater samples belonged to the deep aquifer and fell in the rock dominance zone. Shallow aquifer samples mostly fell in the rainfall zone, suggesting that this aquifer is affected by anthropogenic activities. In contrast, the results suggest that the deep aquifer is heavily influenced by natural processes. 相似文献
9.
Tracing the sources of nitrate in karstic groundwater in Zunyi,Southwest China: a combined nitrogen isotope and water chemistry approach 总被引:1,自引:0,他引:1
Si-Liang Li Cong-Qiang Liu Yun-Chao Lang Zhi-Qi Zhao Zhi-Hua Zhou 《Environmental Earth Sciences》2010,60(7):1415-1423
Nitrate (NO3
−) is major pollutant in groundwater worldwide. Karst aquifers are particularly vulnerable to nitrate contamination from anthropogenic
sources due to the rapid movement of water in their conduit networks. In this study, the isotopic compositions (δ15N–NO3
−, δ15N–NH4
+) and chemical compositions(e.g., NO3
−, NH4
+, NO2
−, K+) were measured in groundwater in the Zunyi area of Southwest China during summer and winter to identify the primary sources
of contamination and characterize the processes affecting nitrate in the groundwater. It was found that nitrate was the dominant
species of nitrogen in most of the water samples. In addition, the δ15N–NO3
− values of water samples collected in summer were lower than those collected in winter, suggesting that the groundwater received
a significant contribution of NO3
− from agricultural fertilizer during the summer. Furthermore, the spatial variation in the concentration of nitrate and the
δ15N–NO3
− value indicated that some of the urban groundwater was contaminated with pollution from point sources. In addition, the distribution
of δ15N–NO3
− values and the relationship between ions in the groundwater indicated that synthetic and organic fertilizers (cattle manure)
were the two primary sources of nitrate in the study area, except in a few cases where the water had been contaminated by
urban anthropogenic inputs. Finally, the temporal and spatial variation of the water chemistry and isotopic data indicated
that denitrification has no significant effect on the nitrogen isotopic values in Zunyi groundwater. 相似文献
10.
Groundwater salinization processes in shallow coastal aquifer of Djeffara plain of Medenine, Southeastern Tunisia 总被引:3,自引:3,他引:0
Rim Trabelsi Kamel Abid Kamel Zouari Houcine Yahyaoui 《Environmental Earth Sciences》2012,66(2):641-653
Urban and industrial development and the expansion of irrigated agriculture have led to a drastic increase in the exploitation
of groundwater resources. The over-exploitation of coastal aquifers has caused a seawater intrusion and has seriously degraded
groundwater quality. The shallow coastal aquifer of the Djeffara plain, southeastern Tunisia constitutes an example of water
resource suffering an intensive and uncontrolled pumping for irrigation. Intensive exploitation of the aquifer and climate
aridity caused a decrease in piezometric level and an increase in salinity. According to the hydrochemical data (Cl−, SO4
2−, NO3
−, HCO3
−, Br−, Ca2+, Mg2+, Na+, K+) and the stable isotope composition (oxygen-18 and deuterium content), groundwater salinization in the investigated system
is caused by three main processes: (i) salts dissolution especially in the central part of Jerba and around Medenine plain;
(ii) evaporation process; and (iii) seawater intrusion which caused the increase in salinity in the peninsula of El Jorf,
in Jerba and in the North of Ben Gardane. 相似文献
11.
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
12.
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
13.
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
14.
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
15.
Geochemical characterization of groundwater from northeastern part of Nagpur urban,Central India 总被引:2,自引:1,他引:1
Hydrogeochemical investigations are carried out in the northeastern part of Nagpur urban to assess the quality of groundwater
for its suitability for drinking and irrigation purposes. Groundwater samples are collected from both shallow and deep aquifers
to monitor the hydrochemistry of various ions. The groundwater quality of the area is adversely affected by urbanization as
indicated by distribution of EC and nitrate. In the groundwater of study area, Ca2+ is the most dominant cation and Cl− and HCO3
− are the dominant anions. Majority of the samples have total dissolved solids values above desirable limit and most of them
belong to very hard type. As compared to deep aquifers, shallow aquifer groundwaters are more polluted and have high concentration
of NO3
−. The analytical results reveal that most of the samples containing high nitrate also have high chloride. Major hydrochemical
facies were identified using Piper trilinear diagram. Alkaline earth exceeds alkalis and weak acids exceed strong acids. Shoeller
index values reveal that base-exchange reaction exists all over the area. Based on US salinity diagram most of samples belong
to high salinity-low sodium type. A comparison of groundwater quality in relation to drinking water standards showed that
most of the water samples are not suitable for drinking purpose. 相似文献
16.
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
17.
A detailed water quality analysis was carried out in the quaternary aquifer system of the marginal alluvial plain (Ganga Plain)
in Bah Tahsil, Agra district, India. The electrical conductivity of 50 samples each from dug wells, hand pumps and tube wells
was analysed for the study of salinity levels in shallow, intermediate and deep aquifers. Out of 50, 20 samples of each were
also analysed for other chemical constituents such as Na+, K+, Cl−, F− and TDS. The analyses show drastic changes in the salinity levels of shallow, intermediate and deep aquifers. The deep aquifers
are more saline compared to the shallow and intermediate aquifers. On the contrary, the concentration of chemical constituents
such as Na+, K+, Cl− and F− was more in the shallow aquifers compared to the deep aquifers. Moreover, there is an indication that the salinity and concentration
of the above chemical constituents also escalate with time in each aquifer. The chemical constituents such as Na+, K+, Cl−, F− and TDS range from 51 to 165 mg/l, 1 to 14 mg/l, 224 to 1,459 mg/l, 0 to 1.5 mg/l and 750 to 2,650 mg/l, respectively. Over
a 3-year period, the salinity levels have sharply increased and the average F level has increased by 0.1–0.3 mg/l. An attempt
has been made here to discuss the factors causing the variation and escalation of chemical constituents and salinity in the
water of the three aquifers. 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.
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
20.
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