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1.
Adsorption of arsenic by natural aquifer material in the San Antonio-El Triunfo mining area, Baja California, Mexico 总被引:1,自引:0,他引:1
Several experiments of arsenic (As) adsorption by aquifer material of the San Antonio-El Triunfo (SA-ET) mining area were
conducted to test the feasibility of this material acting as a natural control for As concentrations in groundwater. This
aquifer material is mineralogically complex, composed of quartz, feldspar, calcite, chlorite, illite, and magnetite/hematite.
The total iron content (Fe2O3) in the fine fraction is ∼12%, whereas Fe2O3 in the coarse fraction is <10 wt%. The experimental percent total As adsorbed vs. pH curves obtained match the topology of
total As adsorbed onto iron oxi-hydroxides surface (arsenate + arsenite; high adsorption at low pH, low adsorption at high
pH). A maximum of about 80% adsorbed in the experiments suggests the presence of arsenite in the experimental solutions. The
experimental adsorption isotherm at pH 7 indicates saturation of surface sites at high solute concentrations. Surface titration
of the aquifer material indicates a point of zero charge (PZC) for the adsorbent of about 8 to 8.5 (PZC for iron oxyhydroxides
=7.9–8.2). Comparison between experimental and modeled results (using the MICROQL and MINTEQA2 geochemical modeling and speciation
computer programs) suggests that As is being adsorbed mostly by oxyhydroxides surfaces in the natural environment. Based on
an estimated retardation factor (R), the travel time of the As plume from the SA-ET area to La Paz and Los Planes is about 700 to 5000 years.
Received: 17 March 1997 · Accepted: 8 September 1997 相似文献
2.
A hydrogeochemical survey was conducted on Pico Island (Azores archipelago) in order to evaluate the groundwater chemistry
patterns and the main mineralization processes. Samples were from cold waters and corresponded mainly to sodium chloride type.
Conductivity measurements were ∼82–9790 μS/cm and suggest the existence of highly mineralized waters. In fact, 18% had a conductivity
>5130 μS/cm and the total dissolved solid (TDS) value for two of the wells was from the brackish water range. The changes
in groundwater composition are because of two main processes: (1) silicate mineral dissolution, especially in a few springs
located at high altitude and (2) water salinization in the coastal area, as a result of saltwater intrusion and sea-salt spraying.
The salinization process corresponds to a binary mixing system, as suggested by the chloride and δ18O data, and explains the sharp concentration increase in major and minor species detected in several wells.
Received: 23 July 1999 · Accepted: 8 December 1999 相似文献
3.
The Jharia coalfield is the most important and active minig region; it experiences groundwater inflow and affects groundwater levels in overlying aquifers, and it provides the basis for a conceptual model of the hydrogeological impacts of coal mining. The several sandstone aquifers of the overburden are separated by aquitards that limit vertical hydraulic connection, but the inflow responds to seasonal events and seems to be linked to shallow groundwater behavior. The mine drainage behavior suggests a hydraulic connection between the mine and the shallower groundwater system. The greatest declines are directly above the panels, with an immediate response to coal mining. The inflow is localized by natural and induced fracture zones and is mostly into recent workings. The groundwater behavior is controlled by hydraulic property changes caused by mine-induced fracturing. The hydrological and chemical qualities of the shallow groundwater regime in 13 mining collieries in Mukunda Block have been investigated. Water samples collected from 30 shallow monitoring dug wells were chosen for the study. Rainfall, runoff, and infiltration rates have been calculated in the area. The water-quality plottings were used to interpret the distribution of individual chemical parameters and in predicting the water quality. The underground mine water has been classified as: (1) unconfined groundwater in the calcareous siltstone and sandstone—its composition is Na, Ca, SO4 and Na-MgHCO3 with moderate total dissolved solids (TDS) 200–1480 ppm; (2) the deep groundwater originating from the coal seams and associated sediments in the near-surface environments—this is a Na-HCO3 water with higher TDS; and (3) spoil dump waters are essentially Na-HCO3 with high TDS. This article presents some hydrologic results and conclusions relating to the hydrogeological and environmental impacts of the coal mining in the Jharia coalfield. 相似文献
4.
Rico, Colorado is a small mountain community that was developed before the turn of the century around and near underground
lead-zinc-silver mines. Today, US regulatory concerns in such communities focus on the metal content, particularly of lead,
in community soils. This study integrates bedrock geology, surficial geology, mineralogy and geochemistry in order to define
the controls on metal distribution in Rico community soils. The principal constituents of concern are As, Pb, and Mn. The
results show that mining-related sources are discrete and localized whereas natural sources, including bedrock (mean Pb content
of 3 500 ppm), colluvium (mean Pb content of 1 410 ppm), and older alluvium (mean Pb content of 744 ppm) are wider spread
and are the principal sources of metals in Rico community soils. Historical mining sites like Rico should be expected to have
significant surficial expressions of mineralized bedrock. In these communities, it is important to accurately define the role
of all metal sources as a foundation for determining environmental liabilities, cleanup guidelines, and health risk assessments.
The application of geology and mineralogy in support of geochemical characterization is necessary to accurately define the
origin and distribution of both anthropogenic and natural metal sources at such sites.
Received: 27 December 1996 · Accepted: 21 February 1997 相似文献
5.
D. S. Leigh 《Environmental Geology》1997,30(3-4):244-251
Gold was discovered in 1829 and mined until about 1940 in north Georgia, particularly within an area known as the Dahlonega
mining district. The mining operations there, which involved mercury amalgamation in stamp mills and sluices, delivered significant
quantities of mercury waste to streams. This paper focuses on the downstream dispersal and storage of mercury in streambank
sediments of two watersheds near Dahlonega, Georgia. Mercury concentrations for individual samples of historical sediment
range from 0.02 to 12.00 ppm, with average values in streambanks near the core of the mining district ranging from 0.2 to
0.6 ppm. Mercury levels rapidly decrease in the downstream direction to concentrations that are slightly above a background
level of 0.04±0.02 ppm. Mercury concentrations also appear to decrease with increasing distance from streambanks. Similar
levels of mercury contamination from former gold mines probably exist in many other parts of the gold-bearing rocks of the
Piedmont of the eastern United States. The bioavailability and environmental hazard posed by the contaminated sediment is
not certain.
Received: 8 January 1996 · Accepted: 29 May 1996 相似文献
6.
The total amount of groundwater resources in the middle and upper Odra River basin is 5200×103 m3/d, or about 7.7% of the disposable groundwater resources of Poland. The average modulus of groundwater resources is about
1.4 L/s/km2. Of the 180 'Major Groundwater Basins' (MGWB) in Poland, 43 are partly or totally located within the study area. The MGWB
in southwestern Poland have an average modulus of groundwater resources about 2.28 L/s/km2 and thus have abundant water resources in comparison to MGWB from other parts of the country.
Several types of mineral waters occur in the middle and upper Odra River basin. These waters are concentrated especially in
the Sudety Mountains. Carbon-dioxide waters, with yields of 414 m3/h, are the most widespread of Sudetic mineral waters.
The fresh waters of the crystalline basement have a low mineralization, commonly less than 100 mg/L; they are a HCO3–Ca–Mg or SO4–Ca–Mg type of water. Various hydrochemical compositions characterize the groundwater in sedimentary rocks. The shallow aquifers
are under risk of atmospheric pollution and anthropogenic effects. To prevent the degradation of groundwater resources in
the middle and upper Odra River basin, Critical Protection Areas have been designated within the MGWB.
Received, January 1995 Revised, May 1996, August 1997 Accepted, August 1997 相似文献
7.
Yvonne S. Anku Bruce Banoeng-Yakubo Daniel K. Asiedu Sandow M. Yidana 《Environmental Geology》2009,58(5):989-997
Hydrochemical data are presented for groundwater samples, collected from fractured aquifers in parts of northern Ghana. The
data was collected to assess the groundwater suitability for domestic and agricultural use. Results of the study reveal that
the pH of the groundwater in the area is slightly acidic to slightly alkaline. The electrical conductivity values, total dissolved
solids (TDS) values and calcium, magnesium and sodium concentrations in the groundwater are generally below the limit set
by the WHO for potable water supply. On the basis of activity diagrams, groundwater from the fractured aquifers appears to
be stable within the montmorillonite field, suggesting weathering of silicate minerals. An inverse distance weighting interpolator
with a power of 2 was applied to the data points to produce prediction maps for nitrate and fluoride. The distribution maps
show the presence of high nitrate concentrations (50–194 mg/l) in some of the boreholes in the western part of the study area
indicating anthropogenic impact on the groundwater. Elevated fluoride level (1.5–4 mg/l), higher than the WHO allowable fluoride
concentration of 1.5, is recorded in the groundwater underlying the northeastern part of the study area, more specifically
Bongo and its surrounding communities of the Upper East region. Results of this study suggest that groundwater from the fractured
aquifers in the area exhibit low sodicity–low salinity (S1–C1), low sodicity–medium salinity (S1–C2) characteristics [United
States Salinity Laboratory (USSL) classification scheme]. All data points from this study plot within the ‘Excellent to good’
category on a Wilcox diagram. Groundwater in this area thus appears to provide irrigation water of excellent quality. The
hydrochemical results indicate that, although nitrate and fluoride concentrations in some boreholes are high, the groundwater
in the study area, based on the parameters analyzed, is chemically potable and suitable for domestic and agricultural purposes. 相似文献
8.
M. Ramakrishna Reddy N. Janardhana Raju Y. Venkatarami Reddy T. V. K. Reddy 《Environmental Geology》2000,39(3-4):342-352
Intensive application of surface water in command areas of irrigation projects is creating water logging problems, and the
increase of groundwater usage in agriculture, industry and domestic purposes (through indiscriminate sinking of wells) is
causing continuous depletion of water levels, drying up of wells and quality problems. Thus the protect aquifers to yield
water continuously at economical cost, the management of water resources is essential. Integrated geological, hydrological
(surface and groundwater) and geochemical aspects have been studied for the development and management of water resources
in drought-prone Cuddapah district. The main lithological units are crystallines, quartzites, shales and limestones. About
91 000 ha of land in the Cuddapah district is irrigated by canal water. A registered ayacut of about 47 000 ha is irrigated
by 1368 minor irrigation tanks. A total of 503 spring channels are identified in the entire district originating from the
rivers/streams, which has the capacity of irrigating about 8700 ha. The average seasonal rise in groundwater level is 7.32 m
in quartzites, 5.35 m in crystallines, 3.82 m in shales, 2.50 m in limestones and 2.11 m in alluvium. Large quantities of
groundwater are available in the mining areas which can be utilised and managed properly by the irrigation department/cultivators
for the irrigation practices. Groundwater assessment studies revealed that 584 million m3 of groundwater is available for future irrigation in the district. From the chemical analysis, the quality of groundwater
in various rock units is within the permissible limits for irrigation and domestic purposes, but at a few places the specific
conductance, chloride and fluoride contents are high. This may be due to untreated effluents, improper drainage system and/or
the application of fertilisers.
Received: 10 June 1998 · Accepted: 15 November 1998 相似文献
9.
Distribution and environmental impact of coal-mining wastes in Upper Silesia, Poland 总被引:8,自引:0,他引:8
About 50 million tonnes/year of waste rock from coal-mining is generated in the limited area of the thickly populated Upper
Silesian Coal Basin (USCB) in Poland. There are 380 coal-mining waste dumps, including 76 active dump sites covering over
2,000 ha. About 15-16 million tonnes/year of waste rock is being reused for civil engineering purposes in the same area. This
brings about a problem of ground water deterioration by constituents leached from waste rock exposed to atmospheric conditions.
The major factors determining the ground water contamination potential from waste rock are chloride salinity, sulfur content
and acid generation potential. The concept behind the presented studies was to provide data for correct evaluation and prediction
of contaminant release from the waste rock, based on the characterization of coal-mining waste properties, as well as on long-term
laboratory, lysimetric and field studies. The results show that coal-mining waste dumps can be a long-term source of ground
water contamination, lasting for decades and increasing with time. Ground water down-gradient from the disused 15–30-years-old
part of the studied dump displays high and increasing acidification, high TDS, SO4, and the highest, still increasing concentrations of Mn, Fe and Zn. Cost-effective and efficient pollution control measures,
similar to the presented design and construction elements of the dump site, can mitigate the negative environmental impacts.
Received: 3 July 1997 · Accepted: 9 September 1998 相似文献
10.
Aquifers above high-extraction underground coal mines are not affected by mine drainage, but they may still exhibit changes
in groundwater chemistry due to alterations in groundwater flow induced by mine subsidence. At two active longwall mine sites
in Illinois, USA, glacial-drift aquifers were largely unaffected by mining, but the geochemistry of the bedrock aquifers changed
during the post-mining water-level recovery. At the Jefferson site, brackish, high-sulfate water present in the upper bedrock
shale briefly had lower values of total dissolved solids (TDS) after mining due to increased recharge from the overlying drift,
whereas TDS and sulfate increased in the sodium-bicarbonate water present in the underlying sandstone due to downward leakage
from the shale and lateral inflow of water through the sandstone. At the Saline site, sandstones contained water ranging from
brackish sodium-chloride to fresh sodium-bicarbonate type. Post-mining recovery of the potentiometric levels was minimal,
and the water had minor quality changes. Longwall mining affects geochemistry due to subsidence-related fracturing, which
increases downward leakage from overlying units, and due to the temporary potentiometric depression and subsequent recovery,
whereby water from surrounding areas of the aquifer recharges the affected zone above and adjacent to the mine.
Received, December 1998 / Revised, August 1999 / Accepted, August 1999 相似文献
11.
The effect of the Ruseifa municipal landfill on the shallow groundwater aquifers in the area was investigated in two separate sites. The first one was not used since 1994, whereas the other is still being used for dumping. Fourteen electrical resistivity soundings were performed to detect the leachate and its effect on the quality of the groundwater. Results indicated that the solid waste thickness of the landfill was ranged from 3 to 20 m with resistivity value less than 10 Ω m. Based on the resistivity decreases of values less than 5 Ω m, the leachate was detected in the landfill sites at depths ranged from 10 to 50 m. However, the flow direction of the leachate at depth ranging 10–20 m in the terminated site was toward north, whereas the flow direction of the leachate in the site still used for dumping was toward east–northeast which causes the major source of groundwater pollution. 相似文献
12.
D. V. Reddy P. Nagabhushanam M. R. Rao D. S. Mitra B. M. Tripati S. K. Sinha B. Bhadu 《Journal of the Geological Society of India》2011,77(3):239-242
The Oil and Natural Gas Corporation Limited (ONGC), India, embarked upon exploration and exploitation of deep groundwater
under the project named as “Saraswati” in arid Thar desert, Rajasthan, with a societal mission of providing water to the local
people and cattle. A 555 m deep well drilled by the ONGC near Jaisalmer town in 2006 encountered a potential aquifer at a
depth of 450–500 m. Radiocarbon dating of this well water indicated paleorecharge to be >40,000 yr BP (uncorrected) (Before
Present with respect to 1950 AD), while the medium depth (∼200 m) well waters around that area showed an age range of ∼9,000
to 17,000 yr BP (uncorrected). These waters represent pre-Saraswati era recharge, because the mighty Saraswati flowed in this
region between 7000–4000 yr BP. The stable isotope (δD and δ18O) and Total Dissolved Solids (TDS) data of these waters clearly indicated absence of communication between the two aquifers
(deep and medium depth). However, the extension of this deep aquifer needs to be determined. 相似文献
13.
Summary Fe-Ti-P-rich rocks (FTP) are unusual with respect to their mineralogy and bulk composition. Varieties of these rocks are mostly
related to Proterozoic massif-type anorthosites and to a lesser extent to the upper parts of mafic-ultramafic intracratonic
layered complexes and other igneous rock suites. We present results on the geology, mineralogy and geochemistry of a new occurrence
of FTP, associated with mafic rocks in the northwestern part of Iran. The Qareaghaj mafic-ultramafic intrusion (QMUI) is a
small igneous body situated between Palaeozoic sedimentary rocks and a Precambrian low grade metamorphic complex. The QMUI
is composed mainly of non-mineralized mafic and apatite- and Fe-Ti oxide-rich ultramafic rocks. The mafic rocks, mainly coarse-grained
gabbro, microgabbro and amphibolite, have a simple mineral assemblage (plagioclase + clinopyroxene + ilmenite) and based on
field observations, mineralogy and chemical composition are comagmatic. The ultramafic rocks with high proportion of olivine
(∼40–66 vol.%), apatite (∼0.1–16 vol.%), ilmenite (∼11–19 vol.%) and magnetite (∼2–13 vol.%), have unusual bulk compositions
(e.g., SiO2 ∼ 21–30 wt.%, total iron expressed as Fe2O3
tot ∼ 26–42 wt.%, TiO2 ∼ 5–11 wt.%, MgO ∼ 9–20 wt.%, P2O5 up to 5.1 wt.%, Cr ∼ 40–160 ppm, Ni ∼ 7–73 ppm). The FTP forms numerous sill-like layers, ranging in thickness from ∼5 cm
to few meters. These rocks, totally enclosed in mafic rocks with sharp and concordant contacts, show a magmatic lamination
and follow the general NW–SE trend of QMUI. The apatite-rich ultramafic rocks makes up 90–95% of the total ultramafic outcrops
and contain Mg-poor olivine (Mg# ∼ 40–58) and low-Mg spinel (Mg# ∼ 30–44) in contrast to apatite-poor ones (∼60–63 and ∼43–46,
respectively). Field relationships, mineral compositions and geochemical data suggested that the FTP are not related to the
mafic host rocks. On the contrary, they intruded latter into the gabbros during plastic, high temperature deformation in local
shear zones. Fractional crystallization of P-rich ferrobasaltic parental magma at depth, probably in an open magmatic system,
not far from the QMUI magma chamber, is considered as responsible for the formation of the evolved FTP in QMUI. 相似文献
14.
D. B. Panaskar V. M. Wagh A. A. Muley S. V. Mukate R. S. Pawar M. L. Aamalawar 《Arabian Journal of Geosciences》2016,9(13):615
Hydrogeochemical characteristics of groundwater and its suitability for domestic, irrigation, and industrial purposes were evaluated in Nanded Tehsil. A total of 50 representative groundwater samples were collected from dug/bore wells during post monsoon season 2012 and analyzed for major cations and anions. The order of dominance of cation and anions were Na > Ca > Mg > K and HCO3 > Cl > CO3 > SO4 > NO3, respectively. The rock weathering and evaporation processes are dominant in controlling the groundwater quality in the study area. Electrical conductivity (EC) and total dissolved solid (TDS) show high positive correlation with total Hardness (TH), Ca, Na, and Cl. As per the WHO and BIS standards for domestic water purposes, TDS, TH, Ca, Mg, Na, and Cl exceed the safe limits in 16, 22, 6, 18, 12, and 15 %, respectively; therefore, majority of samples show that the groundwater is suitable for drinking. The spatial distribution maps of physicochemical parameters were prepared in ArcGIS. The suitability of groundwater for agriculture purpose was evaluated from EC, TDS, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), and %Na which ranges from excellent to unsuitable, so majority of the groundwater samples are suitable for irrigation. The U.S. Salinity Laboratory (USSL) diagram shows that most of the groundwater samples are characterized as in high salinity-low sodium hazard type water (C3-S1). All the groundwater samples are suitable for industrial use except sample numbers 44 and 48. Thus, most of the groundwater samples from this study confirm the beneficial use of aquifers in the area for domestic, agricultural, and irrigation purposes. However, sample numbers 44 and 48 identify the two aquifers in the study area which are problematic and need particular remedial measures if they are to have beneficial use. 相似文献
15.
The aim of this study was to identify the complex hydrogeological and hydrochemistry conditions of Damt region, through determining
hydrochemical properties of groundwater in the study area. According to the results of hydrochemical analyses, sampled waters
can be divided into three groups: cold, thermal, and mixed waters. Thermal waters in the area are characterized by Na–HCO3, while the cold waters by CaHCO3 facies. HCO3 indiscriminate cation and/or Na-indiscriminate anion are present in many places in the region and indicate generally mixing
water. Only three villages with dental fluorosis observed using water elevated in F− for drinking. Agricultural and liquid waste disposal are the main sources of pollution, leads to increase of Na, Cl, NO3, Cd, and Iron. The groundwater flow is from north, northwest, and northeast to the south. Within this regional trend, structural
controlling groundwater flow along Wadis and it flows from upper reaches of tributaries toward the main channel, then downward
to the south of the study area. The similarity of TDS and Cl concentration at Qa’a Al Haql and Al Nadirah between aquifers
indicates hydraulic continuity between alluvial and the underlying volcanic, while at Damt no hydraulic continuity found between
alluvial, volcanic and Sandstone aquifers. The temporal variation shows slight decrease in the concentration of nitrate and
sulfate of thermal water indicating previously high gas content of nitrogen, hydrogen sulfide in the thermal active region.
The developed conceptual model of water circulation indicates flood waters infiltrate slowly through the wadi bottoms in the
East where Sandstone aquifer outcrops. These waters flow westward, following the westerly dip of the Sandstone through the
effects of gravity, gains heat and dissolve materials as it comes in contact with the numerous dykes, which are the feeders
to the overlying volcanoes and sputter cones. All thermal water samples from Damt region fall into immature water field in
NA–K–Mg diagram. Therefore, the results obtained from the cation geothermometers should be taken into account as doubtful. 相似文献
16.
L. A. Shevenell 《Environmental Geology》2000,39(7):807-815
Within the next 10–15 years, over 35 mines in Nevada will have a lake in their open pit mines after dewatering and cessation
of mining. Of the ten past or existing pit lakes at eight different gold mines for which temporal data are available, most
had near neutral pH, yet most had at least one constituent (e.g., As, SO4, TDS) that exceeded drinking water standards for at least one sampling event. Most samples from pit lakes had TDS exceeding
drinking water standards, but lower than that in the natural Pyramid (TDS≈5,500 mg/l) and Walker (TDS≈14,000 mg/l) Lakes.
In the past century, salinity increased in both natural, terminal lakes, in part due to irrigation withdrawals and evapoconcentration.
The salinity in the pit lakes may also increase through time via evapoconcentration. However, water balance models indicate
that up to 132% (Walker Lake) of the total yearly inflow evaporates from the terminal lakes, whereas steady-state may be reached
in the pit lakes modelled, where evaporative losses account for only ≈6% of the total pit lake volume annually and ≈100% of
the net inflow (groundwater inflow minus outflow, precipitation and runoff into the lake). The effects of evapoconcentration
are expected to be less significant at most pit lakes than at the natural, terminal lakes because (1) evaporation rates are
lower at many pit lakes because they are located at higher elevations than the terminal lakes, and (2) the surface area to
depth ratio of the pit lakes is >1000 times smaller than that of the terminal lakes.
Received: 1 March 1999 · Accepted: 13 April 1999 相似文献
17.
Hydrogeologic data of 455 water wells comprising geologic logs, water qualities, and aquifer test results are analyzed to
determine hydrogeological characteristics, water quality, and sustainable yield of the groundwater resources of Cheju volcanic
island. The groundwater of the island occurs in unconsolidated pyroclastic deposits and clinkers interbedded in highly jointed
basaltic and andesitic rocks as high-level, basal, and parabasal groundwater under unconfined conditions. The total storage
of groundwater is estimated at about 44 billion m3. The average transmissivity and specific yield of the aquifer are at about 0.34 m2 s–1(29300 m2 day–1) and 0.12, respectively. The average annual precipitation is about 3.39 billion m3, of which 1.49 billion m3– equivalent to 44.0% of the total annual precipitation – is recharged into aquifers, with 0.638 billion m3 year–1 of runoff and 1.26 billion m3 year–1 of evapotranspiration. Based on a groundwater budget analysis, the sustainable yield is estimated at about 0.62 billion m3 year–1, equivalent to 41.6% of annual recharge. A low-permeability marine sedimentary formation (Sehwari formation), composed of
loosely cemented sandy silt, was recently found to be situated at 120±68 m below mean sea level. If the said marine sediment
is distributed as a basal formation of the freshwater zone of the island, most of its groundwater will be of parabasal type.
So the marine sediment is one of the most important hydrogeological boundaries and groundwater occurrences in the area.
Received: 16 January 1997 / Accepted: 16 June 1997 相似文献
18.
Impact of geohydrology and neotectonic activity on radon concentration in groundwater of intermontane Doon Valley, Outer Himalaya, India 总被引:1,自引:0,他引:1
Radon concentration was measured in 133 water samples from tubewells, handpumps, dug wells and springs of the Doon Valley,
Outer Himalaya, India. The observed radon values were found to vary from 10 to 154 Bq/l whereas radium in selected water samples
varied from 0.11 to 0.75 Bq/l. Three different clusters of high radon values were observed in the north-western, central and
south-eastern parts of the Doon Valley. These clusters were found to be associated with tectonics (thrust/fault) and associated
uranium mineralization in the area. In general, radon concentration in groundwater was found to be positively correlated with
the depth of the wells, whereas no significant correlation was observed between radon concentration in groundwater and the
water temperature, pH value, conductivity and altitude of the water samples. An attempt has also been made to determine the
nature and extent of aquifers in the Doon Valley on radon concentration in groundwater. The variation in radon concentration
within the groundwater of the study area was found to be controlled by the neotectonic activity and geohydrological processes
that occur in the area. The impact of these activities on radon concentration in groundwater are discussed.
Received: 17 September 1999 · Accepted: 11 April 2000 相似文献
19.
M. Thangarajan 《Environmental Geology》1999,38(3):209-222
Palar River Basin, a crystalline rock region in North Arcot District (Tamil Nadu), India, possesses vast groundwater potential
along and near the river course and its lands are fertile. Serious contamination of both surface water and groundwater has
been reported in this basin as a result of uncontrolled discharge of untreated effluents by the tanning industries for the
last three decades. The health of the rural farming community and people working in the tanning industries has been seriously
affected and they are suffering from occupational diseases such as asthma, chromium ulcers and skin diseases. About an 11000
hectares area of fertile land has lost its fertility. Total dissolved solids (TDS) concentration in groundwater at some pockets
varies from 3000 to 10000 mg/l. As the discharge of effluents is continuing, a prognosis of further pollutant migration is
carried out using a mathematical model. A numerical model of the Upper Palar River Basin was developed using the finite difference
technique coupled with method of characteristics and used to predict TDS migration for the next 20 years. Sensitivity analysis
was carried out to identify the parameters which are influencing the contaminant migration. Sensitivity analysis shows that
advection and not dispersion is the predominant mode of solute migration in Palar Basin. Prognosis using the model confirms
that the polluted area zone as well as the concentration of pollutants in the groundwater will continue to increase in future.
The study also indicated that even if the pollutant sources are reduced to 25% of the present level, the TDS concentration
level in the groundwater, even after 20 years, will not be reduced below 50% of its 1992 level.
Received: 20 June 1998 · Accepted: 26 October 1998 相似文献
20.
Hydrogeological and hydrochemical framework of regional aquifer system in Kali-Ganga sub-basin, India 总被引:5,自引:0,他引:5
The central Ganga Basin is one of the major groundwater reservoirs in India. The Kali-Ganga sub-basin is a micro watershed
of the central Ganga Basin, containing a number of productive aquifers. A detailed hydrogeological investigation was carried
out, which reveals the occurrence of a single-tier aquifer system down to 163 m bgl (metres below ground level), but at places
it is interleaved with clay layers; thus imparting it a two-to three-tier aquifer system. These aquifers are unconfined to
confined in disposition. The transmissivity, storage coefficient and hydraulic conductivity are determined as 2178 m2/day, 1.12×10–5 and 120 m/day, respectively. The groundwater of the basin is fresh, of an alkali-bicarbonate type and is suitable for irrigation
and domestic use. However, in certain areas, extensive agricultural activities, and domestic and industrial effluents have
caused some deterioration of groundwater quality. This study contains data of where the concentration of Fe, Pb, Cd, Cr and
Ni are higher than the permissible limits, which may be hazardous to public health.
Received: 2 March 2000 · Accepted: 3 July 2000 相似文献