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The contamination of groundwater in the aquifer of the La Llagosta basin (Besòs river basin) due to waste disposal in quarries
formerly used for the extraction of dry raw materials has led to the cessation of groundwater extraction for public water
supply. The mobilization of pollutants was largely caused by fluctuations in piezometric levels, which led to the washing
of buried waste. The hydrogeochemical processes associated with uncontrolled waste disposal in these landfilled areas of the
La Llagosta basin aquifer were studied along a flow path that crosses the contaminated area. The PHREEQC code was used to
establish the reactions associated with the different mineral phases through inverse modeling. This transport code, ionic
exchange phenomena, surface reactions and balance (mineral phase) reactions were used to simulate the dilution phenomenon
associated with the pollution after the potential removal of the sources of contamination. One-dimensional advective–dispersive
modeling indicates a substantial reduction in Ca, Mg, Na and SO42− within one year and stabilization within four years. 相似文献
2.
Geochemical study of groundwater from a structurally deformed granitic terrain near Hyderabad (India) was carried out to understand
and evaluate the hydrogeochemical processes and quality of groundwater. Several trace elements (Fe, Mn, Be, Al, V, Cr, Co,
Ni, Cu, Zn, As, Sr, Mo, Cd, Sb, Ba, Pb, U) along with major ions and minor elements were precisely estimated in shallow and
drilled wells to know the suitability of water for drinking and irrigation purposes. Analytical data shows that pH and major
ion chemistry in dug wells and bore wells do not vary significantly, while some trace elements (Fe, Mn, Al, Be, Co, Pb, U
and Zn) vary in dug wells and bore wells, which can be attributed to differential mineral weathering and dissolution/precipitation
reactions along fractures/joints. Although the water is not potable, it was found to be suitable for irrigation with little
danger in the development of harmful level of exchangeable sodium. It is inferred that the chemical composition of the groundwater
in this region is likely to have its origin from silicate weathering reactions and dissolution/precipitation processes supported
by rainfall and groundwater flow. 相似文献
3.
Mukherjee A von Brömssen M Scanlon BR Bhattacharya P Fryar AE Hasan MA Ahmed KM Chatterjee D Jacks G Sracek O 《Journal of contaminant hydrology》2008,99(1-4):31-48
Although arsenic (As) contamination of groundwater in the Bengal Basin has received wide attention over the past decade, comparative studies of hydrogeochemistry in geologically different sub-basins within the basin have been lacking. Groundwater samples were collected from sub-basins in the western margin (River Bhagirathi sub-basin, Nadia, India; 90 samples) and eastern margin (River Meghna sub-basin; Brahmanbaria, Bangladesh; 35 samples) of the Bengal Basin. Groundwater in the western site (Nadia) has mostly Ca-HCO(3) water while that in the eastern site (Brahmanbaria) is much more variable consisting of at least six different facies. The two sites show differences in major and minor solute trends indicating varying pathways of hydrogeochemical evolution However, both sites have similar reducing, postoxic environments (p(e): +5 to -2) with high concentrations of dissolved organic carbon, indicating dominantly metal-reducing processes and similarity in As mobilization mechanism. The trends of various redox-sensitive solutes (e.g. As, CH(4), Fe, Mn, NO(3)(-), NH(4)(+), SO(4)(2-)) indicate overlapping redox zones, leading to partial redox equilibrium conditions where As, once liberated from source minerals, would tend to remain in solution because of the complex interplay among the electron acceptors. 相似文献
4.
The urban groundwater of the central Besòs river basin (the La Llagosta aquifer) has become contaminated due to the infiltration of wastewater from septic tanks and sewage networks, and by industrial activities located in urban areas. The groundwater hydrogeochemistry of the La Llagosta aquifer was characterized using isoconcentration maps, hydrogeochemical diagrams (Piper, Schoeller-Berkaloff) and by analyzing hydrogeochemical changes along a flow-path that crosses an urban and peripheral industrial area in the main alluvial aquifer (the La Llagosta unit). The evolution of cations, anions and heavy metals along the flow path and the use of the PHREEQC numerical code indicate a complex set of geochemical processes, which result from the interaction between the sources of pollution, the groundwater flow and the mineral composition of the aquifer materials. The contaminated groundwater below the urban areas shows high contents of NO(3)(-) (90-100 mg/L) and an increase in the concentrations of Ca(2+) and Mg(2+) which coincides with a decrease in pH. The Eh shows greater variation than the pH along the flow line studied, with values ranging between 56 mV in the industrial area and 370 mV in the urban area. The area with the lowest Eh value coincides with the highest concentrations of dissolved Fe (4.7 mg/L) and Mn (0.22 mg/L). 相似文献
5.
The hydrogeochemical characterization of Coxilha das Lombas Aquifer, Brazil, was studied. Chemical characteristics from 23
groundwater samples and meteoric waters data from public registers were used. The ionic speciation and mineral dissolution/precipitation
was calculated by EQ3/6 package software. The results showed low total dissolved solids (TDS) values and slightly acidic pH.
The concentration of most abundant ions usually followed this trend Cl−>HCO3
+>SO4
2−>Na+. The characteristics of groundwaters and the chemistry similarity with the meteoric waters reflect their short residence
time, due to high hydraulic conductivity, and low degree of water/rock interactions, due to sands composed mainly of quartz. 相似文献
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7.
Hydrogeochemistry and Groundwater Quality Assessment of Lower Part of the Ponnaiyar River Basin, Cuddalore District, South India 总被引:7,自引:0,他引:7
Jeevanandam M Kannan R Srinivasalu S Rammohan V 《Environmental monitoring and assessment》2007,132(1-3):263-274
The Lower Ponnaiyar River Basin forms an important groundwater province in South India constituted by Tertiary formations
dominated by sandstones and overlain by alluvium. The region enjoyed artesian conditions 50 years back but at present frequent
failure of monsoon and over exploitation is threatening the aquifer. Further, extensive agricultural and industrial activities
and urbanization has resulted in the increase in demand and contamination of the aquifer. To identify the sources and quality
of groundwater, water samples from 47 bore wells were collected in an area of 154 km2 and were analysed for major ions and trace metals. The results reveal that the groundwater in many places is contaminated
by higher concentrations of NO3, Cl, PO4 and Fe. Four major hydrochemical facies Ca–Mg–Cl, Na–Cl, Ca–HCO3 and Na–HCO3 were identified using Piper trilinear diagram. Salinity, sodium adsorption ratio, and sodium percentage indicate that most
of the groundwater samples are not suitable for irrigation as well as for domestic purposes and far from drinking water standards.
The most serious pollution threat to groundwater is from nitrate ions, which are associated with sewage and fertilizers application.
The present state of the quality of the lower part of Ponnaiyar River Basin is of great concern and the higher concentration
of toxic metals (Fe and Ni) may entail various health hazards. 相似文献
8.
Hydrogeological and biogeochemical constrains of arsenic mobilization in shallow aquifers from the Hetao basin, Inner Mongolia 总被引:6,自引:0,他引:6
Guo H Zhang B Li Y Berner Z Tang X Norra S Stüben D 《Environmental pollution (Barking, Essex : 1987)》2011,159(4):876-883
Little is known about the importance of drainage/irrigation channels and biogeochemical processes in arsenic distribution of shallow groundwaters from the Hetao basin. This investigation shows that although As concentrations are primarily dependent on reducing conditions, evaporation increases As concentration in the centre of palaeo-lake sedimentation. Near drainage channels, groundwater As concentrations are the lowest in suboxic-weakly reducing conditions. Results demonstrate that both drainage and irrigation channels produce oxygen-rich water that recharges shallow groundwaters and therefore immobilize As. Groundwater As concentration increases with a progressive decrease in redox potential along the flow path in an alluvial fan. A negative correlation between SO42− concentrations and δ34S values indicates that bacterial reduction of SO42− occurs in reducing aquifers. Due to high concentrations of Fe (>0.5 mg L−1), reductive dissolution of Fe oxides is believed to cause As release from aquifer sediments. Target aquifers for safe drinking water resources are available in alluvial fans and near irrigation channels. 相似文献
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