WorldWideScience

Sample records for groundwater dissolves salt

  1. Composition of dissolved organic matter in groundwater

    Science.gov (United States)

    Longnecker, Krista; Kujawinski, Elizabeth B.

    2011-05-01

    Groundwater constitutes a globally important source of freshwater for drinking water and other agricultural and industrial purposes, and is a prominent source of freshwater flowing into the coastal ocean. Therefore, understanding the chemical components of groundwater is relevant to both coastal and inland communities. We used electrospray ionization coupled with Fourier-transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to examine dissolved organic compounds in groundwater prior to and after passage through a sediment-filled column containing microorganisms. The data revealed that an unexpectedly high proportion of organic compounds contained nitrogen and sulfur, possibly due to transport of surface waters from septic systems and rain events. We matched 292 chemical features, based on measured mass:charge ( m/z) values, to compounds stored in the Kyoto Encyclopedia of Genes and Genomes (KEGG). A subset of these compounds (88) had only one structural isomer in KEGG, thus supporting tentative identification. Most identified elemental formulas were linked with metabolic pathways that produce polyketides or with secondary metabolites produced by plants. The presence of polyketides in groundwater is notable because of their anti-bacterial and anti-cancer properties. However, their relative abundance must be quantified with appropriate analyses to assess any implications for public health.

  2. Determination of some dissolved trace metals from groundwater in ...

    African Journals Online (AJOL)

    ... of the groundwater at both Flic en Flac and GRNW were not significant in 1998. ... The data demonstrated the potential for concentrations of some dissolved ... 74 of the Environmental Protection Act 1991 and cited as the new Environmental ...

  3. Integrated sampling and analytical approach for common groundwater dissolved gases.

    Science.gov (United States)

    McLeish, Kimberley; Ryan, M Cathryn; Chu, Angus

    2007-12-15

    A novel passive gas diffusion sampler (PGDS) combines sampling, storage and direct injection into a single gas chromatograph (GC). The sampler has a 4.5 mL internal volume when deployed, is easy to operate, and eliminates sample-partitioning. The associated GC method analyzes for a large, dynamic sampling range from a single, small volume injection. Dissolved gases were separated on parallel Rt-Molsieve 5A and Rt-Q-PLOT columns and eluted solutes were quantified using a pulse discharge helium ionization detector (PD-HID). The combined sampling and analytical method appears to be less prone to systematic bias than conventional sampling and headspace partitioning and analysis. Total dissolved gas pressure used in tandem with the PGDS improved the accuracy of dissolved gas concentrations. The incorporation of routine measurements of dissolved biogeochemical and permanent gases into groundwater investigations will provide increased insight into chemical and biological processes in groundwater and improve chemical mass balance accuracy.

  4. Dissolved helium and TDS in groundwater from Bhavnagar in Gujarat: Unrelated to seismic events between August 2000 and January 2001

    Indian Academy of Sciences (India)

    S K Gupta; R D Deshpande

    2003-03-01

    Temporal variations have been observed in both dissolved helium and TDS in the form of increase in basaltic and decrease in alluvial aquifers. The increase in basaltic aquifers has been explained by enhanced pumping of old groundwater with relatively higher concentration of dissolved helium and salt, whereas the decrease in alluvial aquifers has been explained by dilution from the post monsoon groundwater recharge. Therefore, the observed temporal variations cannot be ascribed to the contemporary enhanced seismic activity in this region since August-September 2000.

  5. Assessing dissolved methane patterns in central New York groundwater

    Directory of Open Access Journals (Sweden)

    Lauren E. McPhillips

    2014-07-01

    New hydrological insights for this region: There was no significant difference between methane concentrations in valleys versus upslope locations, in water wells less than or greater than 1 km from a conventional gas well, and across different geohydrologic units. Methane concentrations were significantly higher in groundwater dominated by sodium chloride or sodium bicarbonate compared with groundwater dominated by calcium bicarbonate, indicating bedrock interactions and lengthy residence times as controls. A multivariate regression model of dissolved methane using only three variables (sodium, hardness, and barium explained 77% of methane variability, further emphasizing the dominance of geochemistry and hydrogeology as controls on baseline methane patterns.

  6. Electrodialysis-ion exchange for the separation of dissolved salts

    Energy Technology Data Exchange (ETDEWEB)

    Baroch, C.J. [Wastren, Inc., Westminster, CO (United States); Grant, P.J. [Wastren, Inc., Hummelstown, PA (United States)

    1995-10-01

    The Department of Energy generates and stores a significant quantity of low level, high level, and mixed wastes. As some of the DOE facilities are decontaminated and decommissioned, additional and possibly different forms of wastes will be generated. A significant portion of these wastes are aqueous streams containing acids, bases, and salts, or are wet solids containing inorganic salts. Some of these wastes are quite dilute solutions, whereas others contain large quantities of nitrates either in the form of dissolved salts or acids. Many of the wastes are also contaminated with heavy metals, radioactive products, or organics. Some of these wastes are in storage because a satisfactory treatment and disposal processes have not been developed. There is considerable interest in developing processes that remove or destroy the nitrate wastes. Electrodialysis-Ion Exchange (EDIX) is a possible process that should be more cost effective in treating aqueous waste steams. This report describes the EDIX process.

  7. Stability of salt in the Permian salt basin of Kansas, Oklahoma, Texas and New Mexico, with a section on dissolved salts in surface water

    Science.gov (United States)

    Bachman, George Odell; Johnson, Ross Byron

    1973-01-01

    bedded salt from subsurface dissolution depends chiefly on the isolation of the salt from moving ground water that is not completely saturated with salt. Karst topography is a major criterion for recognizing areas where subsurface dissolution has been active in the past; therefore, the age of the karst development is needed to provide the most accurate estimate of the dissolution rate. The Ogallala Formation-of Pliocene age is probably the most widespread deposit in the Permian salt basin that can be used as a point of reference for dating the development of recent topography. It is estimated that salt has been dissolved laterally in the vicinity of Carlsbad, New Mexico, at an average rate of about 6-8 miles per million years. Estimates of future rates of salt dissolution and the resulting lateral retreat of the underground dissolution front can be projected with reasonable confidence for southeastern New Mexico on the assumption that the climatic changes there in the past 4 million years are representative of climatic changes that may be expected in the near future of geologic time. Large amounts of salt are carried by present-day rivers in the Permian salt basin; some of the salt is derived from subsurface salt beds, but dissolution is relatively slow. Ground-water movement through the Permian salt basin is also relatively slow.

  8. Dissolved Organic Carbon 14C in Southern Nevada Groundwater and Implications for Groundwater Travel Times

    Energy Technology Data Exchange (ETDEWEB)

    Hershey, Ronald L. [Nevada University, Reno, NV (United States). Desert Research Institute; Fereday, Wyall [Nevada University, Reno, NV (United States). Desert Research Institute; Thomas, James M [Nevada University, Reno, NV (United States). Desert Research Institute

    2016-08-01

    Dissolved inorganic carbon (DIC) carbon-14 (14C) ages must be corrected for complex chemical and physical reactions and processes that change the amount of 14C in groundwater as it flows from recharge to downgradient areas. Because of these reactions, DIC 14C can produce unrealistically old ages and long groundwater travel times that may, or may not, agree with travel times estimated by other methods. Dissolved organic carbon (DOC) 14C ages are often younger than DIC 14C ages because there are few chemical reactions or physical processes that change the amount of DOC 14C in groundwater. However, there are several issues that create uncertainty in DOC 14C groundwater ages including limited knowledge of the initial (A0) DOC 14C in groundwater recharge and potential changes in DOC composition as water moves through an aquifer. This study examines these issues by quantifying A0 DOC 14C in recharge areas of southern Nevada groundwater flow systems and by evaluating changes in DOC composition as water flows from recharge areas to downgradient areas. The effect of these processes on DOC 14C groundwater ages is evaluated and DOC and DIC 14C ages are then compared along several southern Nevada groundwater flow paths. Twenty-seven groundwater samples were collected from springs and wells in southern Nevada in upgradient, midgradient, and downgradient locations. DOC 14C for upgradient samples ranged from 96 to 120 percent modern carbon (pmc) with an average of 106 pmc, verifying modern DOC 14C ages in recharge areas, which decreases uncertainty in DOC 14C A0 values, groundwater ages, and travel times. The HPLC spectra of groundwater along a flow path in the Spring Mountains show the same general pattern indicating that the DOC compound composition does not change along this flow path

  9. Removal of both dissolved and particulate iron from groundwater

    NARCIS (Netherlands)

    Teunissen, K.; Abrahamse, A.; Leijssen, H.; Rietveld, L.; Van Dijk, H.

    2008-01-01

    Iron is the primary source for discolouration problems in the drinking water distribution system. The removal of iron from groundwater is a common treatment step in the production of drinking water. Even when clear water meets the drinking water standards, the water quality in the distribution syste

  10. Removal of both dissolved and particulate iron from groundwater

    NARCIS (Netherlands)

    Teunissen, K.; Abrahamse, A.; Leijssen, H.; Rietveld, L.; Van Dijk, H.

    2008-01-01

    Iron is the primary source for discolouration problems in the drinking water distribution system. The removal of iron from groundwater is a common treatment step in the production of drinking water. Even when clear water meets the drinking water standards, the water quality in the distribution

  11. Effect of salt on aerobic biodegradation of petroleum hydrocarbons in contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Foght, J.; Semple, K.; Pooley, K.; Guigard, S.; Biggar, K. [Alberta Univ., Edmonton, AB (Canada)

    2005-07-01

    Biodegradation can be limited by low concentrations of dissolved oxygen and other terminal electron acceptors, low nutrient concentrations, low temperatures and potentially by low numbers of indigenous hydrocarbon-degrading microbes in inhospitable environments. At flare pit sites, salt is a common co-contaminant in subsurface sediments and groundwater contaminated with crude oil. There are few published reports on the effects of salt on hydrocarbon degradation by soil or freshwater microbial communities. In this study, subsurface sediment and groundwater were collected and stored. Five grams of sediment and 50 ml of groundwater were added to flasks, providing replicate indigenous microbial populations. Nutrients were added to certain flasks as autoclaved solutions of ammonium nitrate and potassium phosphate. Positive and negative controls were included in each test series. Flasks were sealed with neoprene stoppers and unsealed briefly to introduce fresh oxygen to maintain aerobic conditions. Results indicate that nutrient addition is required for significant aliphatic but not aromatic hydrocarbon mineralization. Salt was found to be inhibitory to general metabolic activity. Salt concentrations above 1 per cent wt/vol resulted in increased lag times and a lower extent of mineralization. Inhibitory effects observed included increased lag times and decreased rates and extents of mineralization. Low levels of salt were sometimes stimulatory, which may be explained by the salt providing a more ionically balanced medium for the microbes, or by the dispersal of clays to provide a larger surface area for attachment of cells or for access to trace nutrients. It was noted that certain flasks within a replicate set experienced a long lag time before eventually and suddenly beginning to mineralize the substrate at a rate similar to that of less stressed flasks. The lag time may be considered as an adaptation period of the consortium to the stressors, during which there is

  12. Effect of salt on aerobic biodegradation of petroleum hydrocarbons in contaminated groundwater.

    Science.gov (United States)

    Ulrich, Ania C; Guigard, Selma E; Foght, Julia M; Semple, Kathleen M; Pooley, Kathryn; Armstrong, James E; Biggar, Kevin W

    2009-02-01

    Hydrocarbon-contaminated soil and groundwater at oil and gas production sites may be additionally impacted by salts due to release of produced waters. However, little is known about the effect of salt on the in-situ biodegradation of hydrocarbons by terrestrial microbes, especially at low temperatures. To study this effect, we prepared a groundwater-soil slurry from two sites in Canada: a former flare pit site contaminated with flare pit residue (Site A), and a natural gas processing facility contaminated with natural gas condensate (Site B). The slurry with its indigenous microbes was amended with radiolabeled hydrocarbons dissolved in free product plus nutrients and/or NaCl, and incubated in aerobic biometer flasks with gyrotory shaking at either 25 or 10 degrees C for up to 5 weeks. Cumulative production of (14)CO(2) was measured and the lag time, rate and extent of mineralization were calculated. For Site A, concentrations of NaCl >or=1% (w/v) delayed the onset of mineralization of both (14)C-hexadecane and (14)C-phenanthrene under nutrient-amended conditions, but once biodegradation began the degradation rates were similar over the range of salt concentrations tested (0-5% NaCl). For Site B, increasing concentrations of NaCl >or=1% (w/v) increased the lag time and decreased the rate and extent of mineralization of aliphatic and aromatic substrates. Of particular interest is the observation that low concentrations of salt (

  13. Tracing natural gas transport into shallow groundwater using dissolved nitrogen and alkane chemistry in Parker County, Texas

    Science.gov (United States)

    Larson, T.; Nicot, J. P.; Mickler, P. J.; Darvari, R.

    2015-12-01

    Dissolved methane in shallow groundwater drives public concern about the safety of hydraulic fracturing. We report dissolved alkane and nitrogen gas concentrations and their stable isotope values (δ13C and δ15N, respectively) from 208 water wells in Parker county, Texas. These data are used to differentiate 'stray' natural gas and low temperature microbial methane, and (2) estimate the ratio of stray gas to groundwater. The ratio of (gas-phase) stray natural gas to groundwater is estimated by correlating dissolved methane and nitrogen concentrations and dissolved nitrogen δ15N values. Our hypothesis is groundwater exposed to high volumes of stray natural gas have high dissolved methane concentrations and low dissolved nitrogen concentrations and δ15N values. Alternatively, groundwater exposed to low volumes of stray gas-phase natural gas have elevated dissolved methane, but the concentration of dissolved nitrogen and its d15N value is atmospheric. A cluster of samples in Parker county have high concentrations of dissolved methane (>10mg/L) with d13Cmethane and alkane ratios (C1/C2+C3) typical of natural gas from the Barnett Shale and the Strawn Formation. Coupling dissolved nitrogen concentrations and δ15N values with these results, we suggest that few of the wells in this cluster preserve large gas to water ratios. Many samples with high dissolved methane concentrations have atmospheric dissolved nitrogen concentrations and δ15N values, providing evidence against high flux natural gas transport into shallow groundwater. These results demonstrate that dissolved nitrogen chemistry, in addition to dissolved alkane and noble gas measurements, may be useful to discern sources of dissolved methane and estimate ratios of stray natural gas-water ratios.

  14. The removal kinetics of dissolved organic matter and the optical clarity of groundwater

    Science.gov (United States)

    Chapelle, Francis H.; Shen, Yuan; Strom, Eric W.; Benner, Ronald

    2016-09-01

    Concentrations of dissolved organic matter (DOM) and ultraviolet/visible light absorbance decrease systematically as groundwater moves through the unsaturated zones overlying aquifers and along flowpaths within aquifers. These changes occur over distances of tens of meters (m) implying rapid removal kinetics of the chromophoric DOM that imparts color to groundwater. A one-compartment input-output model was used to derive a differential equation describing the removal of DOM from the dissolved phase due to the combined effects of biodegradation and sorption. The general solution to the equation was parameterized using a 2-year record of dissolved organic carbon (DOC) concentration changes in groundwater at a long-term observation well. Estimated rates of DOC loss were rapid and ranged from 0.093 to 0.21 micromoles per liter per day (μM d-1), and rate constants for DOC removal ranged from 0.0021 to 0.011 per day (d-1). Applying these removal rate constants to an advective-dispersion model illustrates substantial depletion of DOC over flow-path distances of 200 m or less and in timeframes of 2 years or less. These results explain the low to moderate DOC concentrations (20-75 μM; 0.26-1 mg L-1) and ultraviolet absorption coefficient values ( a 254 United States. The nearly uniform optical clarity of groundwater, therefore, results from similarly rapid DOM-removal kinetics exhibited by geologically and hydrologically dissimilar aquifers.

  15. In-well degassing issues for measurements of dissolved gases in groundwater.

    Science.gov (United States)

    Roy, J W; Ryan, M C

    2010-01-01

    Measurement of dissolved gases in groundwater is becoming increasingly common and important. Many of these measurements involve monitoring or sampling within wells or from water pumped from wells. We used total dissolved gas pressure (TDGP) sensors placed in the screened section of various wells (4 to 72 m deep) to assess the dissolved gas conditions for open wells compared to the conditions when sealed (i.e., isolated from the atmosphere) with a hydraulic packer (one well) or when pumped. When the packer was installed (non-pumping conditions), TDGP rose from 3.1 atm (314 kPa), with declines noted when the packer was removed or deflated. While pumping, TDGP measured in many of the wells rose to substantially higher levels, up to 4.0 atm (408 kPa) in one case. Thus, when groundwater is gas charged, the background aquifer TDGP, and likewise the dissolved gas concentrations, may be substantially higher than initially measured in open wells, indicating significant in-well degassing. This raises concerns about past and current methods of measuring the dissolved gases in groundwater. Additional procedures that may be required to obtain representative measurements from wells include (1) installing in-well hydraulic packers to seal the well, or (2) pumping to bring in fresh groundwater. However, observed transient decreased TDGPs during pumping, believed to result from gas bubble formation induced by drawdown in the well below a critical pressure (relative to TDGP), may disrupt the measurements made during or after pumping. Thus, monitoring TDGP while pumping gas-charged wells is recommended. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

  16. Numerical Modelling of Dissolving and Driving Exploitation of Potash Salt in the Qarhan Playa——A Coupled Model of Reactive olute Transport and Chemical Equilibrium in a Multi-component Underground Brine System

    Institute of Scientific and Technical Information of China (English)

    LI Wenpeng; LIU Zhenying

    2008-01-01

    Firstly, the macroscopic chemical equilibrium state of a series of chemical reactions between intercrystal brine and its media salt layer (salt deposit) in Qarhan Salt Lake was studied by using the Pitzer theory. The concept of macroscopic solubility product and its relation with accumulated ore dissolving ratio were presented, which are used in the numerical model of dissolving and driving exploitation of potassium salt in Qarhan Salt Lake. And secondly, with a model forming idea oftransport model for reacting solutes in the multi-component fresh groundwater system in porous media being a reference, a two-dimensional transport model coupled with a series of chemical reactions in a multi-component brine porous system (salt deposits) was developed by using the Pitzer theory.Meanwhile, the model was applied to model potassium/magnesium transport in Qarhan Salt Lake in order to study the transfer law of solid and liquid phases in the dissolving and driving process and to design the optimal injection/abstraction strategy for dissolving and capturing maximum Potassium/Magnesium in the mining of salt deposits in Qarhan Salt Lake.

  17. Stochastic modeling of salt accumulation in the root zone due to capillary flux from brackish groundwater

    NARCIS (Netherlands)

    Shah, S.H.H.; Vervoort, R.W.; Suweis, S.; Guswa, A.J.; Rinaldo, A.; Zee, van der S.E.A.T.M.

    2011-01-01

    Groundwater can be a source of both water and salts in semiarid areas, and therefore, capillary pressure–induced upward water flow may cause root zone salinization. To identify which conditions result in hazardous salt concentrations in the root zone, we combined the mass balance equations for salt

  18. Characteristic monitoring of groundwater-salt transportation and input-output in inland arid irrigation area.

    Science.gov (United States)

    Xu, Cundong; Zhang, Hongyang; Han, Liwei; Zhai, Luxin

    2014-11-01

    The rules of microscopic water-salt transportation can be revealed and the impact on the macroscopic water and soil resources can be further predicted by selecting a typical study area and carrying out continuous monitoring. In this paper, Jingtaichuan Electrical Lifting Irrigation District in Gansu Province (hereinafter called as JingDian irrigation district (JID)) located at the inland desert region of northwest China was selected as study area. Based on the groundwater-salt transportation data of representative groundwater monitoring wells in different hydrogeological units, the groundwater-salt evolution and transportation tendency in both closed and unclosed hydrogeological units were analyzed and the quantity relative ratio relationship of regional water-salt input-excretion was calculated. The results showed that the salt brought in by artificial irrigation accounts for the highest proportion of about 63.99% and the salt carried off by the discharge of irrigation water accounts for 66.42%, namely, the water-salt evolution and transportation were mainly controlled by artificial irrigation. As the general features of regional water-salt transportation, groundwater salinity and soil salt content variation were mainly decided by the transportation of soil soluble salt which showed an obvious symbiosis gathering regularity, but the differentiation with insoluble salt components was significant in the transportation process. Besides, groundwater salinity of the unclosed hydrogeological unit presented a periodically fluctuating trend, while the groundwater salinity and soil salt content in water and salt accumulation zone of the closed hydrogeological unit showed an increasing tendency, which formed the main occurrence area of soil secondary salinization.

  19. Gases dissolved in groundwaters: analytical methods and examples of applications in central Italy

    Energy Technology Data Exchange (ETDEWEB)

    Chiodini, G. [Osservatorio Vesuviano, Napoli (Italy)

    1998-12-31

    A quick method to analyse dissolved gases in natural waters is described. First partial results show that useful information on the geochemical processes affecting a variety of hydrogeological systems can be obtained from the study of dissolved gases. The study of the CO{sub 2} dissolved in the groundwaters of Central Italy indicates that one of the main factor controlling the P{sub CO2} values in these groundwaters is the input of a deeply originated gas phase. These leakage processes generally occur in correspondence with buried structural highs of the carbonate basement acting as both traps for the gas produced at depth and sources of high CO{sub 2} fluxes toward the surface. This CO{sub 2} causes significant increases in the P{sub {sub O}2} values of shallow groundwaters. The total carbon balance of two regional aquifers has been used to estimate the production rate of deep CO{sub 2} in Tyrrhenian Central Italy. These average production rates, with 5 X 10{sup 6}mol km{sup -2} y{sup -1} both at Stifone and at Colli Albani, are five times higher than the value assumed as baseline for areas of high heat flow, i.e., 10{sup 6} km{sup -2} y{sup -1}.

  20. Using Dissolved Organic Carbon Isotopes for Groundwater Age Dating in Southern Nevada, USA

    Science.gov (United States)

    Thomas, James; Hershey, Ronald; Fereday, Wyatt

    2016-04-01

    Dissolved organic carbon (DOC) 14C offers a method to calculate groundwater ages that is more straightforward than dissolved inorganic carbon (DIC) 14C. To obtain corrected DIC 14C groundwater ages requires models that account for chemical and physical processes that affect both 13C and 14C. This is especially true in carbonate-rock aquifers where a fair amount of dissolution and precipitation of carbonate minerals can occur. A first important step in calculating 14C DOC groundwater ages is to determine the initial 14C DOC (A0) values of the groundwater recharge. For this study, recharge area groundwater samples of DOC 14C, collected from 14 different sites, were used to determine the recharge DOC 14C values. These values ranged from 96 to 120 percent modern carbon (pmc), with an average value of 106.2 pmc. These 14C A0 values support the use of a 100 pmc 14C A0 pre-bomb value to calculate DOC 14C groundwater ages for southern Nevada. Several conditions to successfully use DOC 14C to date groundwater need to be met. First, soluble organic carbon content of aquifers needs to be low, so that little DOC is added to the groundwater as it flows from recharge areas down gradient in an aquifer. For this study, volcanic and carbonate aquifer outcrop rocks showed that these rocks contained low soluble organic carbon. Second, it is important that the DOC does not change character down a flow path, which could indicate transformation of DOC along a flow path and/or addition of DOC to the groundwater. Although specific DOC compounds could not be identified for samples collected at four sites, all four groundwater sample spectra show the same general shape over the duration of the HPLC run indicating that the DOC compound composition of groundwater does not significantly change from up-gradient to down-gradient. Third, another factor that could greatly affect DOC 14C groundwater age calculations is matrix diffusion/adsorption of DOC 14C. Laboratory experiments showed that

  1. Role of dissolved salts in thermophoresis of DNA: lattice-Boltzmann-based simulations.

    Science.gov (United States)

    Hammack, Audrey; Chen, Yeng-Long; Pearce, Jennifer Kreft

    2011-03-01

    We use a lattice Boltzmann based Brownian dynamics simulation to investigate the dependence of DNA thermophoresis on its interaction with dissolved salts. We find the thermal diffusion coefficient D{T} depends on the molecule size, in contrast with previous simulations without electrostatics. The measured S{T} also depends on the Debye length. This suggests thermophoresis of DNA is influenced by the electrostatic interactions between the polymer beads and the salt ions. However, when electrostatic forces are weak, DNA thermophoresis is not found, suggesting that other repulsive forces such as the excluded volume force prevent thermal migration.

  2. An overview of dissolved organic carbon in groundwater and implications for drinking water safety

    Science.gov (United States)

    Regan, S.; Hynds, P.; Flynn, R.

    2017-06-01

    Dissolved organic carbon (DOC) is composed of a diverse array of compounds, predominantly humic substances, and is a near ubiquitous component of natural groundwater, notwithstanding climatic extremes such as arid and hyper-arid settings. Despite being a frequently measured parameter of groundwater quality, the complexity of DOC composition and reaction behaviour means that links between concentration and human health risk are difficult to quantify and few examples are reported in the literature. Measured concentrations from natural/unpolluted groundwater are typically below 4 mg C/l, whilst concentrations above these levels generally indicate anthropogenic influences and/or contamination issues and can potentially compromise water safety. Treatment processes are effective at reducing DOC concentrations, but refractory humic substance reaction with chlorine during the disinfection process produces suspected carcinogenic disinfectant by-products (DBPs). However, despite engineered artificial recharge systems being commonly used to remove DOC from recycled treated wastewaters, little research has been conducted on the presence of DBPs in potable groundwater systems. In recent years, the capacity to measure the influence of organic matter on colloidal contaminants and its influence on the mobility of pathogenic microorganisms has aided understanding of transport processes in aquifers. Additionally, advances in polymerase chain reaction techniques used for the detection, identification, and quantification of waterborne pathogens, provide a method to confidently investigate the behaviour of DOC and its effect on contaminant transfer in aquifers. This paper provides a summary of DOC occurrence in groundwater bodies and associated issues capable of indirectly affecting human health.

  3. Characteristics and role of groundwater dissolved organic matter on arsenic mobilization and poisoning in Bangladesh

    Science.gov (United States)

    Tareq, Shafi M.; Maruo, Masahiro; Ohta, Keiichi

    The fluorescence and molecular weight characteristics of dissolved organic matter (DOM) in groundwater of Bangladesh were investigated to evaluate its multiple roles on arsenic (As) mobilization and poisoning. Fluorescence properties of DOM were measured in groundwater samples collected from two As contaminated areas of Bangladesh (Faridpur at the Ganges floodplain and Sonargaon at the Meghna floodplain) from different locations and depths. The three dimensional excitation-emission matrix (3DEEM) fluorescence spectra of groundwater samples showed two characteristic peaks around Ex/Em = 335-365 nm/435-480 nm for fulvic-like peaks and peak at around Ex/Em = 275-290 nm/310-335 nm for the protein-like materials. The similarity of fluorescence spectra of groundwater and surface water of both the study areas with high intensity of fluorescence and its strong correlation with DOC reflect the in situ generation of fluorescent DOM from sedimentary organic matter (SOM) and recent recharge of terrestrial labile organic carbon into shallow aquifer. High performance size-exclusion chromatography (HPSEC) analysis of DOM shows positive correlations between fluorescence intensities (FI) of small molecular fractions (0.65 kDa) and As concentrations, with the signatures of protein-like peaks of DOM in groundwater. This result provides new evidence that small molecular weight fraction of DOM in groundwater of Bangladesh can play an important role on As mobilization and toxicity. In addition, high concentration of fluorescence materials in DOM of As contaminated groundwater of Bangladesh may pose a threat to public health.

  4. Dissolved gasesous hydrocarbons in shallow groundwater of Lower Saxony, Germany - Revisited 2016

    Science.gov (United States)

    Schloemer, Stefan; Illing, Christian J.; Blumenberg, Martin; Oest, Johanna; Elbracht, Jörg

    2017-04-01

    Many concerns arise within the public and government/political institutions over potential groundwater contamination from deep drilling operations. For this reason we initiated a baseline study in 2014 on the distribution of dissolved methane, ethane and propane in shallow groundwater ( 1000 groundwater wells, Schloemer et al., 2016) of Lower Saxony, which includes the major petroleum and natural gas provinces in Germany. We observed a variation of dissolved methane concentration over 7 orders of magnitude (20 nl/l to 60 ml/l [v/v]). Methane delta13C compositions ranged from -110‰ to +25‰ vs VPDB, narrowly clustering around -70‰ at high concentrations but being increasingly more variable at lower concentrations (-40‰ to -80‰)). Most of the data are clearly indicative for methanogenic processes, samples unusually enriched in delta13C can best be explained by secondary methane oxidation. Although some general regional trend can be observed, results are highly variable within short lateral distances or within different aquifers/filter depths. Frequently ethane (27% of samples, median 50nl/l) and occasionally propane (8%, median 23nl/l) has been detected. Lacking the carbon isotope composition of these homologues and thus solely based on the extremely low concentrations and atypical ethane/propane ratios, these have been tentatively interpreted as ubiquitous microbial background. From the original 2014 sample set around 100 wells have been selected for consecutive testing through 2015. In spring 2016 a total number of 1100 wells have been sampled, 700 of which had already been part of the initial study, providing us with the unique opportunity to assess long term variations. The overall comparison of these 700 samples revealed only small relative variations in methane concentrations (mostly ± 5‰ in 25% of samples). Minor variations could be related to uncertainties in laboratory analysis (± 10% in concentration, ± 0.5‰ delta13C). To which extent the

  5. Impact of artificial recharge on dissolved noble gases in groundwater in California.

    Science.gov (United States)

    Cey, Bradley D; Hudson, G Bryant; Moran, Jean E; Scanlon, Bridget R

    2008-02-15

    Dissolved noble gas concentrations in groundwater can provide valuable information on recharge temperatures and enable 3H-3He age-dating with the use of physically based interpretive models. This study presents a large (905 samples) data set of dissolved noble gas concentrations from drinking water supply wells throughout California, representing a range of physiographic, climatic, and water management conditions. Three common interpretive models (unfractionated air, UA; partial re-equilibration, PR; and closed system equilibrium, CE) produce systematically different recharge temperatures or ages; however, the ability of the different models to fit measured data within measurement uncertainty indicates that goodness-of-fit is not a robust indicator for model appropriateness. Therefore caution is necessary when interpreting model results. Samples from multiple locations contained significantly higher Ne and excess air concentrations than reported in the literature, with maximum excess air tending toward 0.05 cm3 STP g(-1) (deltaNe approximately 400%). Artificial recharge is the most plausible cause of the high excess air concentrations. The ability of artificial recharge to dissolve greater amounts of atmospheric gases has important implications for oxidation-reduction dependent chemical reactions. Measured gas concentration ratios suggest that diffusive degassing may have occurred. Understanding the physical processes controlling gas dissolution during groundwater recharge is critical for optimal management of artificial recharge and for predicting changes in water quality that can occur following artificial recharge.

  6. THE HYDROLOGIC CYCLE, UNIDIRECTIONAL CHARTER OF THE DISSOLVED SALTS AND SUSPENDED LOAD

    Directory of Open Access Journals (Sweden)

    Nicolae Florea

    2012-12-01

    Full Text Available In this paper it is underlined that the hydrologic cycle in nature, reversible and regenerating of fresh water, carries out also an unidirectional and irreversible circulation – by means of a fragment of the hydrologic cycle – of the dissolved salts and stream’s suspended load, entailed by the water drained from continents to ocean. The trend is to transfer soluble salts from land to ocean in the same time with the running water on land in the portion of the hydrologic cycle which refers to the water transfer from continents to ocean in order to equilibrate the annual water balance of the hydrologic cycle. But, one can realize here and there some local salt accumulations in salt soils or in salt lakes within areas without drainage in arid climate; these salts accumulations are cases of local hydrologic cycles „grafted” along the way of water on land (to ocean. The energy necessary to the hydrologic cycle in nature is delivered by the Sun, and the entropy remains at a low level as a consequence of the elimination in this cycle of water vapors with high entropy, and of the receiving of liquid or solid water with low entropy, so that the annual level of entropy is maintained at a low level.

  7. Mathematical model to predict the transport of dissolved arsenic in groundwater influenced by seepage velocity

    Directory of Open Access Journals (Sweden)

    Solomon Ndubuisi Eluozo

    2012-11-01

    Full Text Available Development of mathematical model to predict the transport of dissolved arsenic in groundwater influenced by seepage velocity has been carried out. This model was developed to monitor the rate of concentration at different period and depths. High and low concentrations were observed at different periods and depth as presented in the figures. These conditions can be attributed to soil stratification deposition in the study location and the influence of man-made activities. Based on these facts, it is recommended that risk assessment should be thoroughly done for soil and water and the predicted model should be applied in design and construction of groundwater system in the study area. 

  8. Comparing Modeled and Measured Mercury Speciation in Contaminated Groundwater: Importance of Dissolved Organic Matter Composition.

    Science.gov (United States)

    Richard, Jan-Helge; Bischoff, Cornelia; Biester, Harald

    2016-07-19

    In addition to analytical speciation, reliable Hg species modeling is crucial for predicting the mobility and toxicity of Hg, but geochemical speciation codes have not yet been tested for their prediction accuracy. Our study compares analyses of Hg species in highly Hg-contaminated groundwater (Hgtot: 0.02-4 μmol·L(-1)) at three sites with predictions of Hg speciation obtained from three geochemical codes (WHAM, Visual MINTEQ, PHREEQC) with and without implementation of Hg complexation by dissolved organic matter (DOM). Samples were analyzed for chemical composition, elemental, inorganic, and DOM-bound Hg (Hg(0), Hginorg, HgDOM). Hg-DOM complexation was modeled using three approaches: binding to humic/fulvic acids, binding to thiol-groups, or a combination of both. Results of Hg(0) modeling were poor in all scenarios. Prediction accuracy for Hginorg and HgDOM strongly depended on the assumed DOM composition. Best results were achieved when weaker binding sites, simulated by WHAMs DOM submodel, were combined with strongly binding thiol groups. Indications were found that thiol-DOM ratios in groundwater are likely to be lower than in surface water, highlighting the need for analytical thiol quantification in groundwater DOM. This study shows that DOM quality is a crucial parameter for prediction of Hg speciation in groundwater by means of geochemical modeling.

  9. The source and behavior of iodine dissolving in groundwater in the Mobara gas field, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, Gento [Japan Nuclear Cycle Development Inst., Tokai, Ibaraki (Japan). Tokai Works

    2002-06-01

    The groundwater of the Mobara gas-field in Boso peninsula, eastern Japan, contains considerable amount, around 100 mg/L, of iodine besides dissolved methane. Twelve groundwater samples from gas-producing wells to the aquifer within the Kazusa Group in Mobara and Naruto districts have been analyzed for iodine, pH, Eh, HCO{sub 3}{sup -}, NH{sub 4}{sup +}, SiO{sub 2}(aq), {delta}D, {delta}{sup 18}O, {delta}{sup 13}C{sub CH4} and seventeen elements. There is a good correlation between the concentrations of the dissolved elements to those in marine algae. The principal source of the iodine is believed to be algae buried in the sediments and the iodine has been discharged to the porefluid during decomposition of the tissue. The molar ratio of I{sup -}/Cl{sup -} in the groundwater increases from 1.0 x 10{sup 3} to 2.2 x 10{sup 3} with changing the depth from 2000 to 1000 meters below the surface and turns to decrease from 2.2 x 10{sup 3} to 1.8 x 10{sup 3} with going up from 1000 to 500 meters. This tendency may be caused by the variation of buried organisms due to changing the sedimentary environment. The observed variation in the ratio indicates that the iodine discharged in the pore fluid did not migrate significantly after the deposition of the formation. This paper can be regarded as an English version of Japanese article written by Kamei, which was published on the 'Shigen Chishitsu (Resource Geology)' 51(2)145-151(2000). (author)

  10. Urban Dissolved Silica: Quantifying the Role of Groundwater and Runoff in Wastewater Influent.

    Science.gov (United States)

    Maguire, Timothy J; Fulweiler, Robinson W

    2016-01-01

    Human impacts on silicon (Si) cycling are just being explored. In particular, we know little about the role of urban environments in altering the flux of Si from land to sea. Here we describe the annual load of dissolved Si (DSi) in the influent of the second largest wastewater treatment plant (by volume) in the United States (Deer Island Wastewater Facility, Boston, MA). We partition the ∼69 500 kmol DSi year(-1) influent load between three sources: runoff (12%), groundwater infiltration (39%), and sewage (49%). Based on these results, we hypothesized that instead of being delivered to local rivers, DSi in groundwater and runoff is redirected to the combined stormwater-sewage overflow system. To test this hypothesis we compared long-term (2007-2012) observations of DSi flux from the three urban rivers surrounding Boston to modeled DSi fluxes based on land use and land cover. As predicted, the modeled fluxes were higher than the measured fluxes indicating that the sewage infrastructure of Boston diverts watershed DSi to the treatment plant. This research increases our understanding of human changes to the Si cycle, demonstrates the potential usefulness of DSi as a groundwater infiltration tracer within sewage treatment systems, and highlights the underappreciated interannual variability of riverine DSi fluxes.

  11. Sources of dissolved ammonia and iron in Borovnica alluvial fan groundwater

    Directory of Open Access Journals (Sweden)

    Janko Urbanc

    2014-07-01

    Full Text Available The article deals with chemical and isotopic properties of Borovnica alluvial fan groundwater. Increased concentrations of ammonium and iron were detected in well VB-3 of the Borovnica alluvial fan pumping station. On the basis of analyses it was found out that increased concentrations of both elements are linked to the hydrogeological conditions in the aquifer area. In the upper part of the Borovnica alluvial fan aquifer, layers of clay prevent the access of oxygen to groundwater. This fact, together with the presence of organic matter in the aquifer, creates reduction conditions causing the mobility of iron and manganese in groundwater and the transformation of nitrogen from nitrate into ammonium form. Water from the lower aquifer contains more dissolved oxygen, and on the basis of tritium presence it can be concluded that the water is old up to 50 years. Wells VB-5 and VB-6 capture water from the lower pleistocene aquifer, while well VB-3 recharges also with water from the upper holocene aquifer.

  12. Tracing solid waste leachate in groundwater using δ13 C from dissolved inorganic carbon.

    Science.gov (United States)

    Haarstad, Ketil; Mæhlum, Trond

    2013-01-01

    Tracers can be used to monitor emissions of leachate from landfills in order to detect hydrological pathways and to evaluate environmental pollution. We investigated the stable carbon isotope ratio (δ(13)C-Σ CO (2)) in dissolved inorganic carbon and tritium ((3)H) in water, in addition to the tracers of pollution commonly found in relatively high concentrations in leachate, such as chloride (Cl), organic matter (COD), nitrogen (total and NH(4)-N), iron (Fe), electrical conductivity (EC) and pH. The sampling was performed at seven landfills in the south-eastern part of Norway during a period of 5 years. The objective was to evaluate the potential for tracing leachate in the environment with emphasis on groundwater pollution. By measuring the δ(13)C-Σ CO (2) in leachates, groundwaters and surface waters, the influence of leachate can be identified. The value of δ(13)C-Σ CO (2) varied from-5.5 to 25.9 ‰ in leachate, from-25.4 to 14.7 ‰ in groundwater and from-19.7 to-13.1 ‰ in creeks. A comparison of the carbon isotope ratio with COD, EC and the concentrations of total and NH (4)-N, Cl and Fe showed that δ(13)C-Σ CO (2) is a good tracer for leachate due to higher sensitivity compared to other parameters. The mean concentrations of all the studied parameters were higher in the leachate samples; however, only the carbon isotope ratio showed significant differences between all the groups with strong and middle pollution and samples with low pollution, showing that it can be used as a convenient tracer for leachate in groundwater and surface water. The carbon isotope ratio showed strong correlation between nitrogen, EC and bicarbonate, but not with pH. Tritium was only sporadically found in measureable concentrations and is not considered as a suitable tracer at the sampled locations.

  13. Pencil lead scratches on steel surfaces as a substrate for LIBS analysis of dissolved salts in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Jijon, D; Costa, C, E-mail: judijival@hotmail.com [Departamento de Fisica, Escuela Politecnica Nacional, Ladron de Guevara E11-256, Apartado 17-12-866, Quito (Ecuador)

    2011-01-01

    A new substrate for the quantitative analysis of salts dissolved in liquids with Laser-induced Breakdown Spectroscopy (LIBS) is introduced for the first time. A steel surface scratched with HB pencil lead is introduced as a very efficient and sensitive substrate for quantitative analysis of dissolved salts in liquids. In this work we demonstrate the analytical quality of this system with the analysis of the crystalline deposits formed by the dried aqueous solutions of salts. We focused on analytical parameters such as sensitivity and linearity for the salt cations in each case. Four salts were studied (Sr(NO{sub 3}){sub 2}, LiSO{sub 4}, RbCl and BaCl), at nine different concentrations each. To improve linearity and lower the overall error in the calibration curves, we introduce a novel outlier removal method that takes into account the homogeneity of the dry deposits on the analytical surface.

  14. Characterization of the dissolved organic carbon in landfill leachate-polluted groundwater

    DEFF Research Database (Denmark)

    Christensen, Jette B.; Jensen, Dorthe Lærke; Grøn, Christian

    1998-01-01

    Samples of dissolved organic carbon (DOG) were obtained from landfill leachate-polluted groundwater at Vejen Landfill, Denmark. The humic acids, fulvic acids and the hydrophilic fraction were isolated and purified. Based on DOC measurements, the fulvic acid fraction predominated, accounting...... for about 60% of the total amount of DOC with an apparent molecular weight of about 1800 Da. The hydrophilic fraction constituted about 30% of the total amount of DOC with an apparent molecular weight of about 2100 Da, and the humic acid fraction made up about 10% of the total amount of DOC with an apparent...... molecular weight of about 2600 Da. The elemental compositions of the humic acids, fulvic acids and the hydrophilic fraction were in the ranges typical for humic substances from other origins. The O/C ratios for humic acids, fulvic acids and the hydrophilic fraction were similar in the leachate...

  15. Influences of groundwater extraction on the distribution of dissolved As in shallow aquifers of West Bengal, India.

    Science.gov (United States)

    Neidhardt, Harald; Berner, Zsolt; Freikowski, Dominik; Biswas, Ashis; Winter, Josef; Chatterjee, Debashis; Norra, Stefan

    2013-11-15

    Here we report temporal changes of As concentrations in shallow groundwater of the Bengal Delta Plain (BDP). Observed fluctuations are primarily induced by seasonally occurring groundwater movement, but can also be connected to anthropogenic groundwater extraction. Between December 2009 and July 2010, pronounced variations in the groundwater hydrochemistry were recorded in groundwater samples of a shallow monitoring well tapping the aquifer in 22-25 m depth, where Astot concentrations increased within weeks from 100 to 315 μg L(-1). These trends are attributed to a vertically shift of the hydrochemically stratified water column at the beginning of the monsoon season. This naturally occurring effect can be additionally superimposed by groundwater extraction, as demonstrated on a local scale by an in situ experiment simulating extensive groundwater withdrawal during the dry post-monsoon season. Results of this experiment suggest that groundwater extraction promoted an enduring change within the distribution of dissolved As in the local aquifer. Presented outcomes contribute to the discussion of anthropogenic pumping influences that endanger the limited and yet arsenic-free groundwater resources of the BDP.

  16. Groundwater nitrate reduction versus dissolved gas production: A tale of two catchments.

    Science.gov (United States)

    McAleer, E B; Coxon, C E; Richards, K G; Jahangir, M M R; Grant, J; Mellander, Per E

    2017-05-15

    At the catchment scale, a complex mosaic of environmental, hydrogeological and physicochemical characteristics combine to regulate the distribution of groundwater and stream nitrate (NO3(-)). The efficiency of NO3(-) removal (via denitrification) versus the ratio of accumulated reaction products, dinitrogen (excess N2) & nitrous oxide (N2O), remains poorly understood. Groundwater was investigated in two well drained agricultural catchments (10km(2)) in Ireland with contrasting subsurface lithologies (sandstone vs. slate) and landuse. Denitrification capacity was assessed by measuring concentration and distribution patterns of nitrogen (N) species, aquifer hydrogeochemistry, stable isotope signatures and aquifer hydraulic properties. A hierarchy of scale whereby physical factors including agronomy, water table elevation and permeability determined the hydrogeochemical signature of the aquifers was observed. This hydrogeochemical signature acted as the dominant control on denitrification reaction progress. High permeability, aerobic conditions and a lack of bacterial energy sources in the slate catchment resulted in low denitrification reaction progress (0-32%), high NO3(-) and comparatively low N2O emission factors (EF5g1). In the sandstone catchment denitrification progress ranged from 4 to 94% and was highly dependent on permeability, water table elevation, dissolved oxygen concentration solid phase bacterial energy sources. Denitrification of NO3- to N2 occurred in anaerobic conditions, while at intermediate dissolved oxygen; N2O was the dominant reaction product. EF5g1 (mean: 0.0018) in the denitrifying sandstone catchment was 32% less than the IPCC default. The denitrification observations across catchments were supported by stable isotope signatures. Stream NO3(-) occurrence was 32% lower in the sandstone catchment even though N loading was substantially higher than the slate catchment.

  17. Characterization of Dissolved Organic Carbon in Deep Groundwater from the Witwatersrand Basin

    Science.gov (United States)

    Pullin, M. J.; Hendrickson, S.; Simon, P.; Sherwood Lollar, B.; Wilkie, K.; Onstott, T. C.; Washton, N.; Clewett, C.

    2013-12-01

    This work describes the isolation, fractionation, and chemical analysis of dissolved organic carbon (DOC) in deep groundwater in the Witwatersrand Basin, South Africa. The groundwater was accessed through mining boreholes in gold and diamond mine shafts. Filtered water samples were collected and preserved for later analysis. In some cases, the organic carbon was also collected on DAX-8 and XAD-4 adsorption resins in situ and then transported to the surface for removal, clean-up, and lyophilization. Solid state C-13 NMR analysis of that organic carbon was conducted. Organic compounds were also isolated from the water using solid phase extraction cartridges for later analysis by GC-MS. Absorbance, fluorescence, and HPLC analyses was were used to analyze the DOC in the filtered water samples. C-14 and C-13 isotopic analysis of the organic carbon was also conducted. Identifiable components of the DOC include both organic acids and amino acids. However, initial results indicate that the majority of the subsurface DOC is a complex heterogeneous mixture with an average molecular weight of approximately 1000 Da, although this DOC is less complex than that found in soils or surface water. Finally, we will discuss possible sources of the organic carbon and its biogeochemical cycling in the subsurface.

  18. Terpenoids as major precursors of dissolved organic matter in landfill leachates, surface water, and groundwater

    Science.gov (United States)

    Leenheer, J.A.; Nanny, M.A.; McIntyre, C.

    2003-01-01

    13C NMR analyses of hydrophobic dissolved organic matter (DOM) fractions isolated from a landfill leachate contaminated groundwater near Norman, OK; the Colorado River aqueduct near Los Angeles, CA; Anaheim Lake, an infiltration basin for the Santa Ana River in Orange County, CA; and groundwater from the Tomago Sand Beds, near Sydney, Australia, found branched methyl groups and quaternary aliphatic carbon structures that are indicative of terpenoid hydrocarbon precursors. Significant amounts of lignin precursors, commonly postulated to be the major source of DOM, were found only in trace quantities by thermochemolysis/gas chromatography/mass spectrometry of the Norman Landfill and Tomago Sand Bed hydrophobic DOM fractions. Electrospray/tandem mass spectrometry of the Tomago Sand Bed hydrophobic acid DOM found an ion series differing by 14 daltons, which is indicative of aliphatic and aryl-aliphatic polycarboxylic acids. The product obtained from ozonation of the resin acid, abietic acid, gave a similar ion series. Terpenoid precursors of DOM are postulated to be derived from resin acid paper sizing agents in the Norman Landfill, algal and bacterial terpenoids in the Colorado River and Anaheim Lake, and terrestrial plant terpenoids in the Tomago Sand Beds.

  19. Accounting for Mass Transfer Kinetics when Modeling the Impact of Low Permeability Layers in a Groundwater Source Zone on Dissolved Contaminant Fate and Transport

    Science.gov (United States)

    2014-03-27

    Web: http://www.epa.gov/superfund/sites/rods/fulltext/e1098040. pdf InsideEPA.com. "EPA Seeks To Ease Groundwater Cleanup Policy Following NAS...PERMEABILITY LAYERS IN A GROUNDWATER SOURCE ZONE ON DISSOLVED CONTAMINANT FATE AND TRANSPORT THESIS James M. Bell, Captain, USAF AFIT-ENV-14-M-08...MODELING THE IMPACT OF LOW PERMEABILITY LAYERS IN A GROUNDWATER SOURCE ZONE ON DISSOLVED CONTAMINANT FATE AND TRANSPORT THESIS Presented

  20. Disentangling dissolved oxygen sources in shallow riparian groundwater by stable isotope analysis

    Science.gov (United States)

    Mader, Michael; Porst, David; Schmidt, Christian; van Geldern, Robert; Barth, Johannes

    2017-04-01

    Dissolved oxygen (DO) is one of the strongest oxidation agents in aquatic environments. Besides gas-water-exchange, mixing and mineral oxidation, it is a key player in fundamental biogeochemical processes such as respiration and photosynthesis. These processes also systematically influence stable isotope ratios of DO and of dissolved inorganic carbon (DIC). Simultaneous measurements of DO and DIC concentrations in conjunction with their stable isotope ratios (δ18ODO and δ13CDIC) can thus provide useful tools to quantify oxygen and carbon sources and sinks in natural waters. This study focused on the Selke River in the Harz Mountains (Germany) with steep DO gradients between the stream water and the shallow, adjacent groundwater and associated stable isotope shifts. δ13CDIC values decreased from -13 ‰ to -18 ‰ versus the Vienna Pee Dee Belemnite standard (VPDB) from May to November 2016 and indicated the dominant influence of microbial respiration on the observed DO gradients. With such respiration dominance, we have expected a simultaneous enrichment of δ18ODOto values higher than the one of atmospheric O2 (+23.9 ‰ versus Vienna Standard Mean Ocean Water standard - VSMOW). However, our measurements revealed anomalously low δ18ODO values between +22 ‰ and +18 ‰ versus VSMOW for the same time period. These δ18ODO values were lower than those found in the river. Latter were close to equilibrium with the atmosphere (24.9 ‰ versus VSMOW). The observed δ18ODO ratios in the shallow groundwater can be explained with DO from the river that is subject to fractionation by microbial respiration with a typical fractionation factor (αr) of 0.995. In addition, mass balances revealed that this oxygen pool receives contributions of up to 25 % by diffused oxygen from the vadose zone. Consequently, isotope shifts by respiration and admixture with surface water are masked by diffusion effects that result in a decoupling of carbon and oxygen isotope systematics in

  1. Carbon dioxide and helium dissolved gases in groundwater at central Tenerife Island, Canary Islands: chemical and isotopic characterization

    Science.gov (United States)

    Marrero-Diaz, Rayco; López, Dina; Perez, Nemesio M.; Custodio, Emilio; Sumino, Hirochika; Melián, Gladys V.; Padrón, Eleazar; Hernandez, Pedro A.; Calvo, David; Barrancos, José; Padilla, Germán; Sortino, Francesco

    2015-10-01

    Seismic-volcanic unrest was detected between 2004 and 2005 in the central and northwest zones of Tenerife Island (Canary Islands, Spain). With the aim of strengthening the program of geochemical and seismic-volcanic surveillance, a study of the origin, characteristics, and spatial distribution of dissolved carbon dioxide (CO2) and helium (He) gases in the volcanic aquifer of central Tenerife Island and around Teide volcano was carried out. This work also improves the hydrogeological and hydrogeochemical conceptual model of groundwater flow. Dissolved CO2 concentrations in sampled groundwater are several orders of magnitude higher than that of air-saturated water (ASW) suggesting a significant contribution of non-atmospheric CO2, mainly magmatic, confirmed through measurement of isotopic compositions (δ13CTDIC) and total dissolved inorganic carbon (TDIC) concentrations. A vertical stratification of dissolved CO2 and δ13CTDIC values was observed in the volcanic aquifer at the eastern region of Las Cañadas Caldera. Stratification seems to be controlled by both degree of magmatic CO2-water interaction and CO2 degassing and the original δ13Cco2(g) isotopic composition. The highest dissolved helium (4He) concentrations in groundwater seem to be related to radiogenic contributions resulting from water-rock interactions, and increase with residence time, instead of with endogenous magmatic inputs. Isotopic systematics show that the dissolved gases in groundwater of central Tenerife are variable mixtures of CO2-3He-rich fluids of volcanic-hydrothermal origin with both organic and atmospheric components. The results suggest that the eastern area of Las Cañadas Caldera, the South Volcanic Ridge, and the Teide summit cone are the areas most affected by degassing of the volcanic-hydrothermal system, and they are therefore the most suitable zones for future geochemical monitoring.

  2. Cryptic flows: using multiple tracers to relate dissolved oxygen to hyporheic and groundwater flowpaths in intermittent salmonid streams

    Science.gov (United States)

    Woelfle-Erskine, C. A.; Larsen, L.; Gomez-Velez, J. D.

    2016-12-01

    Intermittent streams provide important habitat for aquatic species, including endangered salmonid fishes, but during prolonged dry periods may become depleted in dissolved oxygen (DO). The rate of depletion and the consequent length of time a pool remains habitable depend on DO and carbon concentrations in groundwater and hyporheic flow, and within-pool metabolic rates. We performed repeat surveys, habitat characterization, and ecohydrologic sampling on two intermittent tributaries of Salmon Creek (Sonoma Co., CA) to elucidate controls on salmonid over-summer survival at the pool scale. Pools exhibited heterogeneity within and across stream reaches in salmonid recruitment and survival during the summer dry period. In classification tree analysis, high conductivity (>310 mS/cm) and low DO (concentration. To distinguish between surface, hyporheic, and groundwater contributions, we measured dissolved organic carbon (DOC) concentration and fluorescence excitation-emission matrices (EEMs), radon (222Rn), and stable isotopes (18O and D) in pools, hyporheic flow, and wells and springs in local aquifers. Radon concentrations in pools ranged from 1.5-2.3 Bq/l, 3-4 orders of magnitude higher than expected for water in equilibrium with air, suggesting substantial groundwater inflow. We developed a five-component PARAFAC model from the EEMs and used with the isotope data to perform an end-member mixing analysis to track water sources and flowpaths. These analyses suggested high separability among groundwaters from aquifers separated by faults and between groundwater and surface water, with groundwater of different age and flowpath length discharging to different pools. Pools with shallow groundwater or hyporheic flow sustained DO concentrations above the threshold for salmonid survival, with shallow groundwater unexpectedly acting as a source of DO to the stream. These inflows were further essential for inhibiting stagnation and promoting reaeration across the air

  3. Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow.

    Science.gov (United States)

    Chatton, Eliot; Labasque, Thierry; de La Bernardie, Jérôme; Guihéneuf, Nicolas; Bour, Olivier; Aquilina, Luc

    2017-01-17

    In the perspective of a temporal and spatial exploration of aquatic environments (surface and groundwater), we developed a technique for field continuous measurements of dissolved gases with a precision better than 1% for N2, O2, CO2, He, Ar, 2% for Kr, 8% for Xe, and 3% for CH4, N2O and Ne. With a large resolution (from 1 × 10(-9) to 1 × 10(-2) ccSTP/g) and a capability of high frequency analysis (1 measure every 2 s), the CF-MIMS (Continuous Flow Membrane Inlet Mass Spectrometer) is an innovative tool allowing the investigation of a large panel of hydrological and biogeochemical processes in aquatic systems. Based on the available MIMS technology, this study introduces the development of the CF-MIMS (conception for field experiments, membrane choices, ionization) and an original calibration procedure allowing the quantification of mass spectral overlaps and temperature effects on membrane permeability. This study also presents two field applications of the CF-MIMS involving the well-logging of dissolved gases and the implementation of groundwater tracer tests with dissolved (4)He. The results demonstrate the analytical capabilities of the CF-MIMS in the field. Therefore, the CF-MIMS is a valuable tool for the field characterization of biogeochemical reactivity, aquifer transport properties, groundwater recharge, groundwater residence time and aquifer-river exchanges from few hours to several weeks experiments.

  4. Applicability of tetrazolium salts for the measurement of respiratory activity and viability of groundwater bacteria

    Science.gov (United States)

    Hatzinger, P.B.; Palmer, P.; Smith, R.L.; Penarrieta, C.T.; Yoshinari, T.

    2003-01-01

    A study was undertaken to measure aerobic respiration by indigenous bacteria in a sand and gravel aquifer on western Cape Cod, MA using tetrazolium salts and by direct oxygen consumption using gas chromatography (GC). In groundwater and aquifer slurries, the rate of aerobic respiration calculated from the direct GC assay was more than 600 times greater than that using the tetrazolium salt 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl tetrazolium chloride (INT). To explain this discrepancy, the toxicity of INT and two additional tetrazolium salts, sodium 3???-[1-(phenylamino)-carbonyl]-3,4-tetrazolium]-bis(4-methoxy-6-nitro) benzenesulfonic acid hydrate (XTT) and 5-cyano-2,3-ditolyl tetrazolium chloride (CTC), to bacterial isolates from the aquifer was investigated. Each of the three tetrazolium salts was observed to be toxic to some of the groundwater isolates at concentrations normally used in electron transport system (ETS) and viability assays. For example, incubation of cells with XTT (3 mM) caused the density of four of the five groundwater strains tested to decline by more than four orders of magnitude. A reasonable percentage (>57%) of cells killed by CTC and INT contained visible formazan crystals (the insoluble, reduced form of the salts) after 4 h of incubation. Thus, many of the cells reduced enough CTC or INT prior to dying to be considered viable by microscopic evaluation. However, one bacterium (Pseudomonas fluorescens) that remained viable and culturable in the presence of INT and CTC, did not incorporate formazan crystals into more than a few percent of cells, even after 24 h of incubation. This strain would be considered nonviable based on traditional tetrazolium salt reduction assays. The data show that tetrazolium salt assays are likely to dramatically underestimate total ETS activity in groundwater and, although they may provide a reasonable overall estimate of viable cell numbers in a community of groundwater bacteria, some specific strains may

  5. Ecosystem-groundwater interactions under changing land uses: Linking water, salts, and carbon across central Argentina

    Science.gov (United States)

    Jobbagy, E. G.; Nosetto, M. D.; Santoni, C. S.; Jackson, R. B.

    2007-05-01

    Although most ecosystems display a one-way connection with groundwater based on the regulation of deep water drainage (recharge), this link can become reciprocal when the saturated zone is shallow and plants take up groundwater (discharge). In what context is the reciprocal link most likely? How is it affected by land use changes? Has it consequences on salt and carbon cycling? We examine these questions across a precipitation gradient in the Pampas and Espinal of Argentina focusing on three vegetation change situations (mean annual rainfall): afforestation of humid (900-1300 mm) and subhumid grassland (700-900 mm/yr of rainfall), annual cultivation of subhumid grasslands (700-800 mm/yr), and annual cultivation of semiarid forests (500-700 mm). Humid and subhumid grasslands have shallow (salinity of tree species. Cultivation with corn and soybean can lead to groundwater consumption in the driest belt of subhumid grassland. Up to five-fold yield increases in lowlands vs. uplands during the driest years indicate a dramatic impact of groundwater use on carbon uptake and groundwater salinization suggests a recharge-to- discharge switch. In dry forests groundwater is not accessible (> 15 m deep) and recharge under natural conditions is null. The establishment of crops, however, triggers the onset of recharge, as evidenced by vadose zones getting wetter and leached of atmospheric chloride. Cropping may cause water table raises leading to a two-way coupling of ecosystems and groundwater in the future, as it has been documented for similar settings in Australia and the Sahel. In the Pampas land use change interacts with groundwater consumption leading to higher carbon uptake (humid and subhumid grasslands) and salt accumulation (subhumid grasslands). In the Espinal (semiarid forest) land use change currently involves a one-way effect on groundwater recharge that may switch to a reciprocal connection if regional water table raises occur. Neglecting the role of groundwater

  6. Predicting salt advection in groundwater from saline aquaculture ponds

    Science.gov (United States)

    Verrall, D. P.; Read, W. W.; Narayan, K. A.

    2009-01-01

    SummaryThis paper predicts saltwater advection in groundwater from leaky aquaculture ponds. A closed form solution for the potential function, stream function and velocity field is derived via the series solutions method. Numerically integrating along different streamlines gives the location (or advection front) of saltwater throughout the domain for any predefined upper time limit. Extending this process produces a function which predicts advection front location against time. The models considered in this paper are easily modified given knowledge of the required physical parameters.

  7. Under-ice eddy covariance flux measurements of heat, salt, momentum, and dissolved oxygen in an artificial sea ice pool

    DEFF Research Database (Denmark)

    Else, B. G T; Rysgaard, S.; Attard, K.

    2015-01-01

    Turbulent exchanges under sea ice play a controlling role in ice mass balance, ice drift, biogeochemistry, and mixed layer modification. In this study, we examined the potential to measure under-ice turbulent exchanges of heat, salt, momentum, and dissolved oxygen using eddy covariance...... as ice grew from 5 to 25 cm thick. Heat, momentum, and dissolved oxygen fluxes were all successfully derived. Quantification of salt fluxes was unsuccessful due to noise in the conductivity sensor, a problem which appears to be resolved in a subsequent version of the instrument. Heat fluxes during...... initial ice growth were directed upward at 10 to 25 W m−2. Dissolved oxygen fluxes were directed downward at rates of 5 to 50mmolm−2 d−1 throughout the experiment, at times exceeding the expected amount of oxygen rejected with the brine during ice growth. Bubble formation and dissolution was identified...

  8. Monitoring the Remediation of Salt-Affected Soils and Groundwater

    Science.gov (United States)

    Bentley, L. R.; Callaghan, M. V.; Cey, E. E.

    2008-12-01

    Salt-affected soil is one of the most common environmental issues facing the petroleum hydrocarbon industry. Large quantities of brines are often co-produced with gas and oil and have been introduced into the environment through, for example, flare pits, drilling operations and pipe line breaks. Salt must be flushed from the soil and tile drain systems can be used to collect salt water which is then be routed for disposal. A flushing experiment over a 2 m deep tile drain system is being monitored by arrays of tensiometers, repeated soil coring, direct push electrical conductivity profiles (PTC), electromagnetic surveys and electrical resistivity tomography (ERT) surveys. Water table elevation is monitored with pressure transducers. Thermocouple arrays provide temperature profiles that are used to adjust electrical conductivity data to standard temperature equivalents. A 20 m by 20 m plot was deep tilled and treated with soil amendments. Numerous infiltration tests were conducted inside and outside the plot area using both a tension infiltrometer and Guelph permeameter to establish changes in soil hydraulic properties and macroporosity as a result of deep tillage. The results show that till greatly diminished the shallow macroporosity and increased the matrix saturated hydraulic conductivity. A header system is used to evenly flood the plot with 10 m3 of water on each of three consecutive days for an approximate total of 7.5 cm of water. The flood event is being repeated four times over a period of 6 weeks. Baseline PTC and ERT surveys show that the salt is concentrated in the upper 2 to 3 m of soil. Tensiometer data show that the soil at 30 cm depth responds within 2 to 3 hours to flooding events once the soil is wetted and begins to dry again after one week. Soil suction at 1.5 m does not show immediate response to the daily flooding events, but is steadily decreasing in response to the flooding and rainfall events. An ERT survey in October will provide the first

  9. Simulating stable carbon and chlorine isotope ratios in dissolved chlorinated groundwater pollutants with BIOCHLOR-ISO

    Science.gov (United States)

    Höhener, Patrick

    2016-12-01

    BIOCHLOR is a well-known simple tool for evaluating the transport of dissolved chlorinated solvents in groundwater, ideal for rapid screening and teaching. This work extends the BIOCHLOR model for the calculation of stable isotope ratios of carbon and chlorine isotopes in chloroethenes. An exact solution for the three-dimensional reactive transport of a chain of degrading compounds including sorption is provided in a spreadsheet and applied for modeling the transport of individual isotopes 12C, 13C, 35Cl, 37Cl from a constant source. The model can consider secondary isotope effects that can occur in the breaking of Csbnd Cl bonds. The model is correctly reproducing results for δ13C and δ37Cl modeled by a previously published 1-D numerical model without secondary isotope effects, and is also reproducing results from a microcosm experiment with secondary chlorine isotope effects. Two applications of the model using field data from literature are further given and discussed. The new BIOCHLOR-ISO model is distributed as a spreadsheet (MS EXCEL) along with this publication.

  10. Dissolved {sup 210}Po and {sup 210}Pb in Guarani aquifer groundwater, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Bonotto, D.M. [Departamento de Petrologia e Metalogenia, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900 Rio Claro, Sao Paulo (Brazil)], E-mail: danielbonotto@yahoo.com.br; Caprioglio, L.; Bueno, T.O.; Lazarindo, J.R. [Departamento de Petrologia e Metalogenia, Universidade Estadual Paulista (UNESP), Av. 24-A No. 1515, C.P. 178, CEP 13506-900 Rio Claro, Sao Paulo (Brazil)

    2009-03-15

    The huge Guarani aquifer located in the South American continent is a very important resource for the region, and its drinking water quality has been investigated according to international standards, inclusive radiological parameters. This paper describes {sup 210}Po and {sup 210}Pb activity concentration data in groundwater samples collected at the Brazilian portion of Guarani aquifer, that is characterized by a great variability of temperature (18-70 deg. C), pH (4.0-9.9), sodium content (0.3-322 mg/l), bicarbonate content (0.1-318 mg/l), etc. Non-expensive alpha counting following some radiochemical steps for extracting and depositing dissolved {sup 210}Po was used. The results of the measurements for samples collected in duplicate yielded a maximum {sup 210}Po activity concentration of 3.7 mBq/L and a maximum {sup 210}Pb activity concentration of 6.7 mBq/l, that are values greatly lower than the guidance level of 0.1 Bq/l established by the WHO for their presence in drinking water. The high sensitivity of the method allowed its applicability on the identification of complexes geochemical and hydrogeological processes occurring in Guarani aquifer as well on the evaluation of the drinking water quality in terms of dose calculations.

  11. Field continuous measurement of dissolved gases with a CF-MIMS: Applications to the physics and biogeochemistry of groundwater flow

    Science.gov (United States)

    Chatton, Eliot; Labasque, Thierry; de La Bernardie, Jérôme; Guihéneuf, Nicolas; Bour, Olivier; Aquilina, Luc

    2017-04-01

    In the perspective of a temporal and spatial exploration of aquatic environments (surface and ground water), we developed a technique for precise field continuous measurements of dissolved gases (N2, O2, CO2, CH4, N2O, H2, He, Ne, Ar, Kr, Xe). With a large resolution (from 1×10-9 to 1×10-2 ccSTP/g) and a capability of high frequency analysis (1 measure every 2 seconds), the CF-MIMS (Continuous Flow Membrane Inlet Mass Spectrometer) is an innovative tool allowing the investigation of a large panel of hydrological and biogeochemical processes in aquatic systems. Based on the available MIMS technology, this study introduces the development of the CF-MIMS (conception for field experiments, membrane choices, ionisation) and an original calibration procedure allowing the quantification of mass spectral overlaps and temperature effects on membrane permeability. This study also presents two field applications of the CF-MIMS (Chatton et al, 2016) involving the well-logging of dissolved gases and the implementation of groundwater tracer tests with dissolved 4He. The results demonstrate the analytical capabilities of the CF-MIMS in the field. Therefore, the CF-MIMS is a valuable tool for the field characterisation of biogeochemical reactivity, aquifer transport properties, groundwater recharge, groundwater residence time and aquifer-river exchanges from few hours to several weeks experiments. Eliot Chatton, Thierry Labasque, Jérôme de La Bernardie, Nicolas Guihéneuf, Olivier Bour and Luc Aquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016.

  12. Effect of TCE concentration and dissolved groundwater solutes on NZVI-promoted TCE dechlorination and H2 evolution.

    Science.gov (United States)

    Liu, Yueqiang; Phenrat, Tanapon; Lowry, Gregory V

    2007-11-15

    Nanoscale zero-valent iron (NZVI) is used to remediate contaminated groundwater plumes and contaminant source zones. The target contaminant concentration and groundwater solutes (NO3-, Cl-, HCO3-, SO4(2-), and HPO4(2-)) should affect the NZVI longevity and reactivity with target contaminants, but these effects are not well understood. This study evaluates the effect of trichloroethylene (TCE) concentration and common dissolved groundwater solutes on the rates of NZVI-promoted TCE dechlorination and H2 evolution in batch reactors. Both model systems and real groundwater are evaluated. The TCE reaction rate constant was unaffected by TCE concentration for [TCE] TCE concentration up to water saturation (8.4 mM). For [TCE] > or = 0.46 mM, acetylene formation increased, and the total amount of H2 evolved at the end of the particle reactive lifetime decreased with increasing [TCE], indicating a higher Fe0 utilization efficiency for TCE dechlorination. Common groundwater anions (5mN) had a minor effect on H2 evolution but inhibited TCE reduction up to 7-fold in increasing order of Cl- TCE reduction but increased acetylene production and decreased H2 evolution. NO3- present at > 3 mM slowed TCE dechlorination due to surface passivation. NO3- present at 5 mM stopped TCE dechlorination and H2 evolution after 3 days. Dissolved solutes accounted for the observed decrease of NZVI reactivity for TCE dechlorination in natural groundwater when the total organic content was small (< 1 mg/L).

  13. Groundwater Flow and Salt Transport at a Sand Tailings Dam: Field Observations and Modelling Results.

    Science.gov (United States)

    Price, A. C.; Mendoza, C. A.

    2004-05-01

    Large volumes of sand tailings are produced during the extraction of bitumen from the oil sands of Northeastern Alberta. The long-term groundwater response and subsequent movement of water and solutes within the large permeable sand tailings storage areas is uncertain. At the Southwest Sand Storage (SWSS) Facility, located at Syncrude's Mildred Lake operations near Ft. McMurray, there is concern that salts from the tailings water may discharge to newly placed reclamation material that covers the sand tailings. This saline discharge water could destroy the reclamation soil structure and negatively impact vegetation. The steady-state groundwater flow and transient movement of salts at the local (bench and slope) and intermediate (pile) scales in the SWSS are investigated. Water levels, seepage and groundwater quality (including TDS) have been measured for over a year along two transects of piezometers installed in the SWSS. The field data have been used to complete traditional hydrogeological interpretations of the site, and to develop a conceptual model of flow and transport. The local and intermediate flow systems and salt transport in the dam are being evaluated with numerical models. The models will allow possible future hydrogeological behaviour of the structure to be tested. Preliminary results show differences in flow systems and salinity distribution that depend on the deposition of the SWSS. This research will facilitate better long-term environmental management of this and similar sites.

  14. Permeable Asphalt: A New Tool to Reduce Road Salt Contamination of Groundwater in Urban Areas.

    Science.gov (United States)

    Dietz, Michael E; Angel, Derek R; Robbins, Gary A; McNaboe, Lukas A

    2016-08-30

    Chloride contamination of groundwater in urban areas due to deicing is a well-documented phenomenon in northern climates. The objective of this study was to evaluate the effects of permeable pavement on degraded urban groundwater. Although low impact development practices have been shown to improve stormwater quality, no infiltration practice has been found to prevent road salt chlorides from entering groundwater. The few studies that have investigated chlorides in permeable asphalt have involved sampling directly beneath the asphalt; no research has looked more broadly at surrounding groundwater conditions. Monitoring wells were installed upgradient and downgradient of an 860 m(2) permeable asphalt parking lot at the University of Connecticut (Storrs, Connecticut). Water level and specific conductance were measured continuously, and biweekly samples were analyzed for chloride. Samples were also analyzed for sodium (Na), calcium (Ca), and magnesium (Mg). Analysis of variance analysis indicated a significantly (p asphalt in impacted urban environments with high ambient chloride concentrations can be beneficial to shallow groundwater quality, although these results may not be generalizable to areas with low ambient chloride concentrations.

  15. Hyporheic flow and dissolved oxygen distribution in fish nests: The effects of open channel velocity, permeability patterns, and groundwater upwelling

    Science.gov (United States)

    Cardenas, M. Bayani; Ford, Aimee E.; Kaufman, Matthew H.; Kessler, Adam J.; Cook, Perran L. M.

    2016-12-01

    Many fish lay their eggs in nests, or redds, which they construct in sediment. The viability of eggs depends on many factors, particularly their oxygenation. Because dissolved oxygen is typically saturated within the stream channel, the dissolved oxygen distribution within the redd depends on whether or not hyporheic flow and transport occur within the sediment. We conducted a series of flume and numerical flow and age transport modeling experiments with the aim of understanding the effects of salmonid redds on the hyporheic transport of young oxygenated water. Hyporheic flow was visualized directly through dye injections. Dissolved oxygen throughout the fish nest was measured using a planar optode. Experiments were conducted at various open channel flow velocities in order to understand their effect on dissolved oxygen, and computational simulations considered various sediment textures and ambient groundwater upwelling rates to add process-level insight. We found that, as also shown by previous studies, the redd topography induces multiscale hyporheic flow that effectively flushes the egg pocket location with younger presumably oxygenated water; older water upwells and forms anoxic zones. This pattern persists even at the lowest channel flow rates and at small upwelling velocities of older ambient groundwater which splits the multiscale hyporheic flow cells into isolated pockets. Large groundwater upwelling rates can shut down all the hyporheic flushing. The relatively coarse texture of the redd further promotes hyporheic flushing of the redd sediment with oxygenated water. Thus, redd morphology and sediment texture optimally combine to induce hyporheic exchange flow that delivers young oxygenated water to the egg pocket.

  16. Simulation of Saline Groundwater Resources Surrounding Salt Lake in Fars Province of Iran

    Science.gov (United States)

    Khayyat Kholghi, Majid; Bastani, Mehrdad; Rakhshandeoroo, Gholamreza

    2010-05-01

    One of the most salty lakes in Iran is located in North-East of Fars province with Electrical Conductivities (EC) of up to 61420 μmhos/cm where water supply depends severely on groundwater resources. Increasing demand for freshwater and overexploitation of the aquifer has caused a drawdown in groundwater levels followed by a seawater intrusion into the coastal aquifer in the vicinity of salt lake. Because of invalid appropriate groundwater flow and solute transport parameter values of the coastal system, studying and modelling of saltwater intrusion in this region is in some way complicated. These unknown parameters are consisted of hydraulic conductivity, porosity, specific storage coefficient and longitudinal dispersivity. In this research, it is tried to facilitate study this problem by means of SEAWAT code, which is suitable for variable-density groundwater flow modelling. In the process of calibrating the simulation and estimating the required unknown parameters, an attempt at inverse modelling of a seawater intrusion system is made by using genetic algorithm method as the optimization procedure. The auto-calibration objective function is defined with the root mean square errors (RMSE) between the observed and the simulated values. The observed data are consisted of both hydraulic heads and concentrations obtained from observation wells. Firstly, the SEAWAT code has been used for forward solution part of salt water intrusion phenomena and then a program is written in MATLAB for coupling the forward and inverse processes. In the developed code, the flow and transport parameters are estimated simultaneously in steady and transient states. Using these estimated parameters in the structure of the simulation consequences more accurate results and more trustable model for next applications in management of the coastal aquifer. Key words seawater intrusion; saline groundwater resources; SEAWAT; genetic algorithm; Fars province

  17. Determination of the origin of dissolved inorganic carbon in groundwater around a reclaimed landfill in Otwock using stable carbon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Porowska, Dorota, E-mail: dorotap@uw.edu.pl

    2015-05-15

    Highlights: • Research showed the origin of DIC in the groundwater around a reclaimed landfill. • Carbon isotope was used to evaluate the contributions of carbon from different sources. • The leachate-contaminated water was isotopically distinct from the natural groundwater. • DIC in the natural groundwater comes from organic matter and dissolution of carbonates. • In the contaminated water, DIC comes from organic matter in the aquifer and landfill. - Abstract: Chemical and isotopic analyses of groundwater from piezometers located around a reclaimed landfill in Otwock (Poland) were performed in order to trace the origin of dissolved inorganic carbon (DIC) in the groundwater. Due to differences in the isotopic composition of carbon from different sources, an analysis of stable carbon isotopes in the groundwater, together with the Keeling plot approach and a two-component mixing model allow us to evaluate the relative contributions of carbon from these sources in the groundwater. In the natural (background) groundwater, DIC concentrations and the isotopic composition of DIC (δ{sup 13}C{sub DIC}) comes from two sources: decomposition of organic matter and carbonate dissolution within the aquifer sediments, whereas in the leachate-contaminated groundwater, DIC concentrations and δ{sup 13}C{sub DIC} values depend on the degradation of organic matter within the aquifer sediments and biodegradation of organic matter stored in the landfill. From the mixing model, about 4–54% of the DIC pool is derived from organic matter degradation and 96–46% from carbonate dissolution in natural conditions. In the leachate-contaminated groundwater, about 20–53% of the DIC is derived from organic matter degradation of natural origin and 80–47% from biodegradation of organic matter stored in the landfill. Partial pressure of CO{sub 2} (P CO{sub 2}) was generally above the atmospheric, hence atmospheric CO{sub 2} as a source of carbon in DIC pool was negligible in the

  18. The dissolved uranium concentration and (234)U/(238)U activity ratio in groundwaters from spas of southeastern Brazil.

    Science.gov (United States)

    Bonotto, Daniel Marcos

    2017-01-01

    This paper describes the natural radioactivity due to (238)U and (234)U in 75 water sources from spas located in 14 municipalities in São Paulo and Minas Gerais states, Brazil. These waters are extensively utilized for drinking in public places, bottling and bathing purposes, among other uses. The water samples were taken from springs and pumped tubular wells drilled into different aquifer systems in the Paraná and Southeastern Shield hydrogeological provinces. The measurements of alpha-emitting radionuclides were also accompanied by the monitoring of temperature, pH, Eh, electrical conductivity, dissolved gases (O2, CO2, H2S, radon, thoron) and major constituents. The dissolved U concentration data were lognormally distributed. The median and mean values corresponded to 0.02 and 0.09 μg/L, respectively. Significant relationships were found among the (234)U/(238)U activity ratio (AR) of dissolved uranium, the total dissolved solids (TDS) and dissolved bicarbonate contents, and also between the AR and dissolution rate in the monitored sites. The logU versus AR diagram used for the hydrogeochemical prospecting of concealed U deposits indicated that the water sources were mainly from reduced environments. The possibility of using the reciprocal of the dissolved U concentration and AR data to determine mixing volumes of different groundwater masses was demonstrated. The highest dissolved U concentration (4.82 μg/L) was well below the maximum allowed by WHO. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Membrane inlet mass spectrometer for the quasi-continuous on-site analysis of dissolved gases in groundwater.

    Science.gov (United States)

    Mächler, Lars; Brennwald, Matthias S; Kipfer, Rolf

    2012-08-07

    We developed a stand-alone system based on a membrane inlet mass spectrometer (MIMS) for measuring dissolved gas concentrations in groundwater under field conditions. The system permits the concentrations of dissolved gases (He, Ar, Kr, N(2), and O(2)) in groundwater to be determined quasi-continuously (every 12 min) with a precision of better than 4% for He and Kr, and with a precision of 1% for Ar, N(2), and O(2) in air-saturated water. The detection limits are below 3 × 10(-9) cm(3)(STP)(g) for the noble gases and below 400 × 10(-9)cm(3)(STP)(g) for N(2) and O(2). The results of a first deployment of the system in the field indicate that changes in the concentration of Ar that result from diel fluctuations of 3°C in the river water temperature were still able to be resolved in groundwater, although the corresponding temperature signal almost vanished.

  20. Adsorbed poly(aspartate) coating limits the adverse effects of dissolved groundwater solutes on Fe(0) nanoparticle reactivity with trichloroethylene.

    Science.gov (United States)

    Phenrat, Tanapon; Schoenfelder, Daniel; Kirschling, Teresa L; Tilton, Robert D; Lowry, Gregory V

    2015-08-02

    For in situ groundwater remediation, polyelectrolyte-modified nanoscale zerovalent iron particles (NZVIs) have to be delivered into the subsurface, where they degrade pollutants such as trichloroethylene (TCE). The effect of groundwater organic and ionic solutes on TCE dechlorination using polyelectrolyte-modified NZVIs is unexplored, but is required for an effective remediation design. This study evaluates the TCE dechlorination rate and reaction by-products using poly(aspartate) (PAP)-modified and bare NZVIs in groundwater samples from actual TCE-contaminated sites in Florida, South Carolina, and Michigan. The effects of groundwater solutes on short- and intermediate-term dechlorination rates were evaluated. An adsorbed PAP layer on the NZVIs appeared to limit the adverse effect of groundwater solutes on the TCE dechlorination rate in the first TCE dechlorination cycle (short-term effect). Presumably, the pre-adsorption of PAP "trains" and the Donnan potential in the adsorbed PAP layer prevented groundwater solutes from further blocking NZVI reactive sites, which appeared to substantially decrease the TCE dechlorination rate of bare NZVIs. In the second and third TCE dechlorination cycles (intermediate-term effect), TCE dechlorination rates using PAP-modified NZVIs increased substantially (~100 and 200%, respectively, from the rate of the first spike). The desorption of PAP from the surface of NZVIs over time due to salt-induced desorption is hypothesized to restore NZVI reactivity with TCE. This study suggests that NZVI surface modification with small, charged macromolecules, such as PAP, helps to restore NZVI reactivity due to gradual PAP desorption in groundwater.

  1. Augmentation of bacterial homeostasis by regulating in situ buffer capacity: Significance of total dissolved salts over acidogenic metabolism.

    Science.gov (United States)

    Venkata Mohan, S; Srikanth, S; Nikhil, G N

    2017-02-01

    During anaerobic fermentation, consequent accumulation of acidic fermented products leads to the failure of pH homeostasis. The present study aimed to comprehend the changes in buffering capacity with addition of sodium salts of hydroxide, bicarbonate and phosphate. The results showed notable augmentation in buffer capacity and cumulative hydrogen production (CHP) compared to control. The influential factor is the amount of undissociated volatile fatty acids released that affected the cell metabolism and consequently biohydrogen generation. It is inferred that among the tested salts, sodium bicarbonate has substantial buffering capacity (β, 0.035± mol) ensuing maximum CHP (468± mL). Besides, bioelectrochemical analysis revealed variations in redox currents that aligned with biohydrogen production. The study provides valuable information on the role of inorganic dissolved salts that would be required to regulate H2 generation and acidogenesis in the aspects of acid-gas phase system.

  2. Seasonal Variation in the Quality of Dissolved and Particulate Organic Matter Exchanged Between a Salt Marsh and Its Adjacent Estuary

    Science.gov (United States)

    Osburn, C. L.; Mikan, M.; Etheridge, J. R.; Burchell, M. R.; Birgand, F.

    2015-12-01

    Salt marshes are transitional ecosystems between terrestrial and marine environments. Along with mangroves and other vegetated coastal habitats, salt marshes rank among the most productive ecosystems on Earth, with critical global importance for the planet's carbon cycle. Fluorescence was used to examine the quality of dissolved and particulate organic matter (DOM and POM) exchanging between a tidal creek in a created salt marsh and its adjacent estuary in eastern North Carolina, USA. Samples from the creek were collected hourly over four tidal cycles in May, July, August, and October of 2011. Absorbance and fluorescence of chromophoric DOM (CDOM) and of base-extracted POM (BEPOM) served as the tracers for organic matter quality while dissolved organic carbon (DOC) and base-extracted particulate organic carbon (BEPOC) were used to compute fluxes. Fluorescence was modeled using parallel factor analysis (PARAFAC) and principle components analysis (PCA) of the PARAFAC results. Of nine PARAFAC components modeled, we used multiple linear regression to identify tracers for recalcitrant DOM; labile soil-derived source DOM; detrital POM; and planktonic POM. Based on mass balance, recalcitrant DOC export was 86 g C m-2 yr-1 and labile DOC export was 49 g C m-2 yr-1. The marsh also exported 41 g C m-2 yr-1 of detrital terrestrial POC, which likely originated from lands adjacent to the North River estuary. Planktonic POC export from the marsh was 6 g C m-2 yr-1. Using the DOM and POM quality results obtained via fluorescence measurements and scaling up to global salt marsh area, we estimated that the potential release of CO2 from the respiration of salt marsh DOC and POC transported to estuaries could be 11 Tg C yr-1, roughly 4% of the recently estimated CO2 release for marshes and estuaries globally.

  3. Dynamics of submarine groundwater discharge and associated fluxes of dissolved nutrients, carbon, and trace gases to the coastal zone (Okatee River estuary, South Carolina)

    Science.gov (United States)

    Porubsky, W.P.; Weston, N.B.; Moore, W.S.; Ruppel, C.; Joye, S.B.

    2014-01-01

    Multiple techniques, including thermal infrared aerial remote sensing, geophysical and geological data, geochemical characterization and radium isotopes, were used to evaluate the role of groundwater as a source of dissolved nutrients, carbon, and trace gases to the Okatee River estuary, South Carolina. Thermal infrared aerial remote sensing surveys illustrated the presence of multiple submarine groundwater discharge sites in Okatee headwaters. Significant relationships were observed between groundwater geochemical constituents and 226Ra activity in groundwater with higher 226Ra activity correlated to higher concentrations of organics, dissolved inorganic carbon, nutrients, and trace gases to the Okatee system. A system-level radium mass balance confirmed a substantial submarine groundwater discharge contribution of these constituents to the Okatee River. Diffusive benthic flux measurements and potential denitrification rate assays tracked the fate of constituents in creek bank sediments. Diffusive benthic fluxes were substantially lower than calculated radium-based submarine groundwater discharge inputs, showing that advection of groundwater-derived nutrients dominated fluxes in the system. While a considerable potential for denitrification in tidal creek bank sediments was noted, in situ denitrification rates were nitrate-limited, making intertidal sediments an inefficient nitrogen sink in this system. Groundwater geochemical data indicated significant differences in groundwater chemical composition and radium activity ratios between the eastern and western sides of the river; these likely arose from the distinct hydrological regimes observed in each area. Groundwater from the western side of the Okatee headwaters was characterized by higher concentrations of dissolved organic and inorganic carbon, dissolved organic nitrogen, inorganic nutrients and reduced metabolites and trace gases, i.e. methane and nitrous oxide, than groundwater from the eastern side

  4. Association between arsenic and different-sized dissolved organic matter in the groundwater of black-foot disease area, Taiwan.

    Science.gov (United States)

    Chen, Ting-Chien; Hseu, Zeng-Yei; Jean, Jiin-Shuh; Chou, Mon-Lin

    2016-09-01

    The formation of an arsenic (As)-dissolved organic matter (DOM) complex is important in driving the release of arsenic in groundwater. This study collected groundwater samples from a 20 m deep well throughout 2014 and separated each into three subsamples by ultrafiltration: high molecular weight-DOM (HDOM, 0.45 μm-10 kDa), medium molecular weight-DOM (MDOM, 10-1 kDa), and low molecular weight-DOM (LDOM, arsenic and the fractional DOM. Based on the EEM records, three fluorescence indicators were further calculated to characterize the DOM sources, including the fluorescence index (FI), the biological index (BI), and the humification index (HI). The experimental results indicated that arsenic in the groundwater was mainly partitioned into the MDOM and LDOM fractions. All fractional DOMs contained humic acid-like substances and were considered as microbial sources. LDOM had the highest humification degree and aromaticity, followed by MDOM and HDOM. The As and DOM association could be formed by a Fe-bridge, which was demonstrated by the Ks values and fourier transform infrared (FTIR) spectra of the DOM. The formation of AsFe-DOM complex was only significant in the MDOM and LDOM.

  5. Groundwater dependence of coastal lagoons: The case of La Pletera salt marshes (NE Catalonia)

    Science.gov (United States)

    Menció, A.; Casamitjana, X.; Mas-Pla, J.; Coll, N.; Compte, J.; Martinoy, M.; Pascual, J.; Quintana, X. D.

    2017-09-01

    Coastal wetlands are among the most productive ecosystems of the world, playing an important role in coastal defense and wildlife conservation. These ecosystems, however, are usually affected by human activities, which may cause a loss and degradation of their ecological status, a decline of their biodiversity, an alteration of their ecological functioning, and a limitation of their ecosystem services. La Pletera salt marshes (NE Spain) are located in a region mainly dominated by agriculture and tourism activities. Part of these wetlands and lagoons has been affected by an incomplete construction of an urban development and in this moment is the focus of a Life+ project, whose aim is to restore this protected area. Several studies have analyzed the role of hydrological regime in nutrients, phytoplankton and zooplankton in this area, however, the role of groundwater was never considered as a relevant factor in the lagoon dynamics, and its influence is still unknown. In this study, the hydrogeological dynamics in La Pletera salt marshes has been analyzed, as a basis to set sustainable management guidelines for this area. In order to determine their dependence on groundwater resources, monthly hydrochemical (with major ions and nutrients) and isotopic (δ18OH2O and δD) campaigns have been conducted, from November 2014 to October 2015. In particular, groundwater from six wells, surface water from two nearby streams and three permanent lagoons, and sea water was considered in these surveys. Taking into account the meteorological data and the water levels in the lagoons, the General Lake Model has been conducted to determine, not only evaporation and rainfall occurring in the lagoons, but also the total inflows and outflows. In addition, the Gonfiantini isotopic model, together with equilibrium chemical-speciation/mass transfer models, has been used to analyze the evaporation and the physicochemical processes affecting the lagoons. Results show that during the dry

  6. Effect of phytoremediation on concentrations of benzene, toluene, naphthalene, and dissolved oxygen in groundwater at a former manufactured gas plant site, Charleston, South Carolina, USA, 1998–2014

    Science.gov (United States)

    Landmeyer, James E.; Effinger, Thomas N.

    2016-01-01

    Concentrations of benzene, toluene, naphthalene, and dissolved oxygen in groundwater at a former manufactured gas plant site near Charleston, South Carolina, USA, have been monitored since the installation of a phytoremediation system of hybrid poplar trees in 1998. Between 2000 and 2014, the concentrations of benzene, toluene, and naphthalene (BT&N) in groundwater in the planted area have decreased. For example, in the monitoring well containing the highest concentrations of BT&N, benzene concentrations decreased from 10,200 µg/L to less than 4000 µg/L, toluene concentrations decreased from 2420 µg/L to less than 20 µg/L, and naphthalene concentrations decreased from 6840 µg/L to less than 3000 µg/L. Concentrations of BT&N in groundwater in all wells were observed to be lower during the summer months relative to the winter months of a particular year during the first few years after installing the phytoremediation system, most likely due to increased transpiration and contaminant uptake by the hybrid poplar trees during the warm summer months; this pathway of uptake by trees was confirmed by the detection of benzene, toluene, and naphthalene in trees during sampling events in 2002, and later in the study in 2012. These data suggest that the phytoremediation system affects the groundwater contaminants on a seasonal basis and, over multiple years, has resulted in a cumulative decrease in dissolved-phase contaminant concentrations in groundwater. The removal of dissolved organic contaminants from the aquifer has resulted in a lower demand on dissolved oxygen supplied by recharge and, as a result, the redox status of the groundwater has changed from anoxic to oxic conditions. This study provides much needed information for water managers and other scientists on the viability of the long-term effectiveness of phytoremediation in decreasing groundwater contaminants and increasing dissolved oxygen at sites contaminated by benzene, toluene, and naphthalene.

  7. Salt overload: How quickly does road salt move from road to groundwater to stream in Baltimore County, MD and what are the effects on soil, groundwater, and stream chemistry?

    Science.gov (United States)

    Moore, J.; Sandosky, B.; McGuire, M.; Casey, R.; Snodgrass, J.; Lev, S. M.

    2013-12-01

    The portion of the landscape covered by roads and other impervious surfaces has increased over the last 50 years. Concurrently, application of road salt, primarily sodium chloride (NaCl), as a de-icer has increased in areas of North America with regular ice and snowfall events. Over the last 10 - 15 years, numerous investigators reported that decades of road salt application has resulted in growing concentrations of sodium and chloride in groundwater and surface water. These road salt-derived elements are present at elevated levels in the surface and groundwaters of impacted watersheds year round. An understudied aspect of road salt impacts has been the role that stormwater management basins (SMBs) play in altering the timing and location of road salt loading to urban and suburban groundwater-surface water systems. SMBs have become common in construction and development over the last 15-20 years. One of the major goals of SMBs is to decrease direct runoff from impervious surfaces to streams by redirecting that runoff into shallow groundwater and thus reducing the flashiness of streams in urban and suburban areas. An unintended consequence of SMBs is that road salt runoff from impervious surfaces is focused into the SMBs and loaded into the vadose zone and shallow groundwater in the winter and then exported to surface water throughout the year. As part of an onging project in a suburb northwest of Baltimore, MD, water samples were collected several times a year from groundwater below two SMBs, a shallow groundwater aquifer downgradient of the SMBs, and a second-order stream for which the aquifer provides baseflow. The major elemental chemistry of the samples was measured. Conductivity and water level loggers were installed to collect data in wells and surface water between grab sampling events. The logger records will be analyzed using spatio-temporal data mining techniques to extract important patterns in the data and to highlight and understand seasonal trends and

  8. Groundwater and surface-water interaction, water quality, and processes affecting loads of dissolved solids, selenium, and uranium in Fountain Creek near Pueblo, Colorado, 2012–2014

    Science.gov (United States)

    Arnold, L. Rick; Ortiz, Roderick F.; Brown, Christopher R.; Watts, Kenneth R.

    2016-11-28

    In 2012, the U.S. Geological Survey, in cooperation with the Arkansas River Basin Regional Resource Planning Group, initiated a study of groundwater and surface-water interaction, water quality, and loading of dissolved solids, selenium, and uranium to Fountain Creek near Pueblo, Colorado, to improve understanding of sources and processes affecting loading of these constituents to streams in the Arkansas River Basin. Fourteen monitoring wells were installed in a series of three transects across Fountain Creek near Pueblo, and temporary streamgages were established at each transect to facilitate data collection for the study. Groundwater and surface-water interaction was characterized by using hydrogeologic mapping, groundwater and stream-surface levels, groundwater and stream temperatures, vertical hydraulic-head gradients and ratios of oxygen and hydrogen isotopes in the hyporheic zone, and streamflow mass-balance measurements. Water quality was characterized by collecting periodic samples from groundwater, surface water, and the hyporheic zone for analysis of dissolved solids, selenium, uranium, and other selected constituents and by evaluating the oxidation-reduction condition for each groundwater sample under different hydrologic conditions throughout the study period. Groundwater loads to Fountain Creek and in-stream loads were computed for the study area, and processes affecting loads of dissolved solids, selenium, and uranium were evaluated on the basis of geology, geochemical conditions, land and water use, and evapoconcentration.During the study period, the groundwater-flow system generally contributed flow to Fountain Creek and its hyporheic zone (as a single system) except for the reach between the north and middle transects. However, the direction of flow between the stream, the hyporheic zone, and the near-stream aquifer was variable in response to streamflow and stage. During periods of low streamflow, Fountain Creek generally gained flow from

  9. Effects of road salts on groundwater and surface water dynamics of socium and chloride in an urban restored stream

    Science.gov (United States)

    Road salts are a growing environmental concern in urban watersheds. We examined groundwater (GW) and surface water (SW) dynamics of Na+ and Cl− in Minebank Run (MBR), an urban stream in Maryland, USA. We observed an increasing salinity trend in this restored stream. Current basef...

  10. Soil water, salt, and groundwater characteristics in shelterbelts with no irrigation for several years in an extremely arid area.

    Science.gov (United States)

    Zhao, Xinfeng; Xu, Hailiang; Zhang, Peng; Fu, Jinyi; Bai, Yuan

    2013-12-01

    This paper is based on long-term monitoring data for soil water, salt content, and groundwater characteristics taken from shelterbelts where there has been no irrigation for at least 5 years. This study investigated the distribution characteristics of soil water and salt content in soils with different textures. The relationships between soil moisture, soil salinity, and groundwater level were analyzed using 3 years of monitoring data from a typical oasis located in an extremely arid area in northwest China. The results showed that (1) the variation trend in soil moisture with soil depth in the shelterbelts varied depending on soil texture. The soil moisture was lower in sandy and loamy shelterbelts and higher in clay shelterbelts. (2) Salinity was higher (about 3.0 mS cm(-1)) in clay shelterbelts and lower (about 0.8 mS cm(-1)) in sandy shelterbelts. (3) There was a negative correlation between soil moisture in the shelterbelts and groundwater level. Soil moisture decreased gradually as the depth of groundwater table declined. (4) There was a positive correlation between soil salinity in the shelterbelts and the depth of groundwater table. Salinity increased gradually as groundwater levels declined.

  11. Passive sampling and analyses of common dissolved fixed gases in groundwater.

    Science.gov (United States)

    Spalding, Brian P; Watson, David B

    2008-05-15

    An in situ passive sampling and gas chromatographic protocol was developed for analysis of the major and several minor fixed gases (He, Ne, H2, N2, O2, CO, CH4, CO2, and N2O) in groundwater. Using argon carrier gas, a HayeSep DB porous polymer phase, and sequential thermal conductivity and reductive gas detectors, the protocol achieved sufficient separation and sensitivity to measure the mixing ratio of all these gases in a single 0.5 mL gas sample collected in situ, stored, transported, and injected using a gastight syringe. Within 4 days of immersion in groundwater, the simple passive in situ sampler, whether initially filled with He or air, attained an equivalent and constant mixing ratio for five of the seven detected gases. The abundant mixing ratio of N2O, averaging 2.6%, indicated that significant denitrification is likely ongoing within groundwater contaminated with uranium, acidity, nitrate, and organic carbon from a group of four closed radioactive wastewater seepage ponds at the Oak Ridge Field Research Center. Over 1000 passive gas samples from 12 monitoring wells averaged 56% CO2, 32.4% N2, 2.6% O2, 2.6% N2O, 0.21% CH4, 0.093% H2, and 0.025% CO with an average recovery of 95 +/- 14% of the injected gas volume.

  12. The effect of pH on the complexation of Cd, Ni and Zn by dissolved organic carbon from leachate-polluted groundwater

    DEFF Research Database (Denmark)

    Christensen, J. B.; Christensen, Thomas Højlund

    2000-01-01

    Complexation of cadmium (Cd), nickel (Ni) and zinc (Zn) by dissolved organic carbon (DOC) in leachate-polluted groundwater was measured using a resin equilibrium method. Metal-DOC complexation was measured at di€erent DOC concentrations over a range of pH values . The results were compared...

  13. Groundwater dynamics in wetland soils control the production and transfer mechanisms of dissolved reactive phosphorus in an agricultural landscape

    Science.gov (United States)

    Dupas, Rémi; Gu, Sen; Gruau, Gérard; Gascuel-Odoux, Chantal

    2015-04-01

    Because of its high sorption affinity on soils solid phase, mitigation options to reduce diffuse P transfer usually focus on trapping particulate P forms delivered via surface flowpaths. Therefore, vegetated buffer zones placed between croplands and watercourses have been promoted worldwide, sometimes in wetland areas. To investigate the risk of such P trapping riparian wetlands (RWs) releasing dissolved P to rivers, we monitored molybdate reactive P (MRP) in the free soil solution of two RWs in an intensively farmed catchment. Two main mechanisms causing MRP release were identified in light of the geochemical and hydrological conditions in the RWs, controlled by groundwater dynamics. First, soil rewetting after the dry summer was associated with the presence of a pool of mobile P, limited in size. Its mobilization started under conditions of water saturation caused by groundwater uprise in RW organo-mineral soil horizons. Second, the establishment of anoxic conditions in the end of the winter caused reductive solubilization of Fe oxide-hydroxide, along with release of P. Comparison between sites revealed that the first MRP release occurred only in a RW with P enriched soils, whereas the second was recorded even in a RW with a low soil P status. Seasonal variations in MRP concentrations in the stream were synchronized with those in RW soils. Hence, enriched and/or periodically anoxic RWs can act as a key component of the P transfer continuum in agricultural landscapes by converting particulate P from croplands into MRP released to rivers.

  14. Groundwater.

    Science.gov (United States)

    Braids, Olin C.; Gillies, Nola P.

    1978-01-01

    Presents a literature review of groundwater quality covering publications of 1977. This review includes: (1) sources of groundwater contamination; and (2) management of groundwater. A list of 59 references is also presented. (HM)

  15. Use of borehole and surface geophysics to investigate ground-water quality near a road-deicing salt-storage facility, Valparaiso, Indiana

    Science.gov (United States)

    Risch, M.R.; Robinson, B.A.

    2001-01-01

    Borehole and surface geophysics were used to investigate ground-water quality affected by a road-deicing salt-storage facility located near a public water-supply well field. From 1994 through 1998, borehole geophysical logs were made in an existing network of monitoring wells completed near the bottom of a thick sand aquifer. Logs of natural gamma activity indicated a uniform and negligible contribution of clay to the electromagnetic conductivity of the aquifer so that the logs of electromagnetic conductivity primarily measured the amount of dissolved solids in the ground water near the wells. Electromagneticconductivity data indicated the presence of a saltwater plume near the bottom of the aquifer. Increases in electromagnetic conductivity, observed from sequential logging of wells, indicated the saltwater plume had moved north about 60 to 100 feet per year between 1994 and 1998. These rates were consistent with estimates of horizontal ground-water flow based on velocity calculations made with hydrologic data from the study area.

  16. THE IMPACT OF DISSOLVED SALTS ON PASTES CONTAINING FLY ASH, CEMENT AND SLAG

    Energy Technology Data Exchange (ETDEWEB)

    Harbour, J.; Edwards, T.; Williams, V.

    2009-09-21

    The degree of hydration of a mixture of cementitious materials (Class F fly ash, blast furnace slag and portland cement) in highly concentrated alkaline salt solutions is enhanced by the addition of aluminate to the salt solution. This increase in the degree of hydration, as monitored with isothermal calorimetry, leads to higher values of dynamic Young's modulus and compressive strength and lower values of total porosity. This enhancement in performance properties of these cementitious waste forms by increased hydration is beneficial to the retention of the radionuclides that are also present in the salt solution. The aluminate ions in the solution act first to retard the set time of the mix but then enhance the hydration reactions following the induction period. In fact, the aluminate ions increase the degree of hydration by {approx}35% over the degree of hydration for the same mix with a lower aluminate concentration. An increase in the blast furnace slag concentration and a decrease in the water to cementitious materials ratio produced mixes with higher values of Young's modulus and lower values of total porosity. Therefore, these operational factors can be fine tuned to enhance performance properties of cementitious waste form. Empirical models for Young modulus, heat of hydration and total porosity were developed to predict the values of these properties. These linear models used only statistically significant compositional and operational factors and provided insight into those factors that control these properties.

  17. Highway deicing salt dynamic runoff to surface water and subsequent infiltration to groundwater during severe UK winters.

    Science.gov (United States)

    Rivett, Michael O; Cuthbert, Mark O; Gamble, Richard; Connon, Lucy E; Pearson, Andrew; Shepley, Martin G; Davis, John

    2016-09-15

    groundwater resource management, highway salt application practice, surface-water - ecosystem management, and decision making on highway drainage to ground.

  18. Temporal changes in dissolved (137)Cs concentrations in groundwater and stream water in Fukushima after the Fukushima Dai-ichi Nuclear Power Plant accident.

    Science.gov (United States)

    Iwagami, Sho; Tsujimura, Maki; Onda, Yuichi; Nishino, Masataka; Konuma, Ryohei; Abe, Yutaka; Hada, Manami; Pun, Ishwar; Sakaguchi, Aya; Kondo, Hiroaki; Yamamoto, Masayoshi; Miyata, Yoshiki; Igarashi, Yasuhito

    2017-01-01

    The concentration of dissolved (137)Cs in groundwater and stream water in the headwater catchments in Yamakiya district, located ∼35 km north west of Fukushima Dai-ichi Nuclear Power Plant (FDNPP), was monitored from June 2011 to July 2013, after the earthquake and tsunami disaster. Groundwater and stream water were sampled at intervals of approximately 2 months at each site. Intensive sampling was also conducted during rainstorm events. Compared with previous data from the Chernobyl NPP accident, the concentration of dissolved (137)Cs in stream water was low. In the Iboishi-yama catchment, a trend was observed for the concentration of dissolved (137)Cs in stream water to decline, which could be divided into two phases by October 2011 (a fast flush of activity as a result of rapid washoff and a slow decline as a result of soil fixation and redistribution processes). The highest (137)Cs concentration recorded at Iboishi-yama was 1.2 Bq/L on August 6, 2011, which then declined to 0.021-0.049 Bq/L during 2013 (in stream water under normal water-flow conditions). During the rainfall events, the concentration of dissolved (137)Cs in stream water increased temporarily. The concentration of dissolved (137)Cs in groundwater at a depth of 30 m at Iboishi-yama displayed a decreasing trend from 2011 to 2013, with a range from 0.039 Bq/L to 0.0025 Bq/L. The effective half-lives of stream water in the initial fast flush and secondary phases were 0.10-0.21 and 0.69-1.5 y, respectively in the three catchments. The effective half-life of groundwater was 0.46-0.58 y at Koutaishi-yama and 0.50-3.3 y at Iboishi-yama. The trend for the concentration of dissolved (137)Cs to decline in groundwater and stream water was similar throughout 2012-2013, and the concentrations recorded in deeper groundwater were closer to those in stream water. The declining trend of dissolved (137)Cs concentrations in stream water was similar to that of the loss of canopy (137)Cs by throughfall, as

  19. Relationship between precipitation quality, shallow ground-water geochemistry, and dissolved aluminum in eastern Maryland. Final report, November 1983-April 1985

    Energy Technology Data Exchange (ETDEWEB)

    Bachman, L.J.; Katz, B.G.

    1986-04-01

    Precipitation, surface water, and shallow ground-water samples were collected in eastern Maryland to determine if acidic precipitation is affecting the chemical quality of water in the Columbia aquifer--an unconsolidated sand and gravel deposit. Thirty-eight water samples were collected from 11 wells, and 9 samples from 3 stream sites between February and June 1984. Ground-water and surface-water samples contained chemical species with significantly different concentration from those of precipitation. Ground-water samples were enriched with bicarbonate, silica, potassium, chloride, and sulfate and had lower hydrogen-ion concentrations than precipitation. Dissolved aluminum in most of the other ground-water samples was at or near the detection limit of 0.01 mg/l.

  20. Growth and photosynthesis responses of Phaeodactylum tricornutum to dissolved organic matter from salt marsh plant and sediment.

    Science.gov (United States)

    Xiao, Yihua; Huang, Qinghui; Chen, Ling; Li, Penghui

    2010-01-01

    The effects of allochthonous dissolved organic matter (DOM) on the growth and photosynthesis of Phaeodactylum tricornutum were investigated. P. tricornutum incubated in f/2 medium was exposed to DOM additives, which were extracted from the plant and sediment samples of a salt marsh in North Branch of the Yangtze estuary, China. During 12 days incubation, the chlorophyll fluorescence parameters of P tricornutum were measured by a Phyto-PAM phytoplankton analyzer. Spectral properties of DOM in algae filtrates were also observed. The concentrations of chlorophyll a, active chlorophyll a, and the maximum quantum yield of photosystem II significantly decreased after four days of incubation, suggesting that the growth and photosynthetic efficiency of P. tricornutum were inhibited. After adding sediment-DOM extract, both a250/a365 (the ratio of the absorption coefficients at 250 and 365 nm) and S values (spectral slope coefficients) of algae filtrates declined in the first two days, which demonstrated a loss of low molecular weight DOM. Parallel factor analysis of fluorescence spectra of DOM in algae filtrates revealed that DOM could be classified into two humic-like and two protein-like components. The fluorescence intensity of tyrosine-like component originating from algae increased significantly during incubation. This study supports the hypothesis that allochthonous DOM derived from salt marsh plant and sediment have a strong influence on the adjacent aquatic ecosystems.

  1. How significant is submarine groundwater discharge and its associated dissolved inorganic carbon in a river-dominated shelf system?

    Directory of Open Access Journals (Sweden)

    Q. Liu

    2012-05-01

    Full Text Available In order to assess the role of submarine groundwater discharge (SGD and its impact on the carbonate system on the northern South China Sea (NSCS shelf, we measured seawater concentrations of four radium isotopes 223,224,226,228Ra along with carbonate system parameters in June–July, 2008. Complementary groundwater sampling was conducted in coastal areas in December 2008 and October 2010 to constrain the groundwater end-members. The distribution of Ra isotopes in the NSCS was largely controlled by the Pearl River plume and coastal upwelling. Long-lived Ra isotopes (228Ra and 226Ra were enriched in the river plume but low in the offshore surface water and subsurface water/upwelling zone. In contrast, short-lived Ra isotopes (224Ra and 223Ra were elevated in the subsurface water/upwelling zone as well as in the river plume but depleted in the offshore surface water. In order to quantify SGD, we adopted two independent mathematical approaches. Using a three end-member mixing model with total alkalinity (TAlk and Ra isotopes, we derived a SGD flux into the NSCS shelf of 2.3–3.7 × 108 m3 day−1. Our second approach involved a simple mass balance of 228Ra and 226Ra and resulted in a first order but consistent SGD flux estimate of 2.2–3.7 × 108 m3 day−1. These fluxes were equivalent to 12–21 % of the Pearl River discharge, but the source of the SGD was mostly recirculated seawater. Despite the relatively small SGD volume flow compared to the river, the associated material fluxes were substantial given their elevated concentrations of dissolved inorganic solutes. In this case, dissolved inorganic carbon (DIC flux through SGD was 153–347 × 109 mol yr−1, or ~23–53 % of the riverine DIC export flux. Our estimates of the groundwater-derived phosphate flux ranged 3–68 × 10

  2. A review of single-sample-based models and other approaches for radiocarbon dating of dissolved inorganic carbon in groundwater

    Science.gov (United States)

    Han, L. F; Plummer, Niel

    2016-01-01

    Numerous methods have been proposed to estimate the pre-nuclear-detonation 14C content of dissolved inorganic carbon (DIC) recharged to groundwater that has been corrected/adjusted for geochemical processes in the absence of radioactive decay (14C0) - a quantity that is essential for estimation of radiocarbon age of DIC in groundwater. The models/approaches most commonly used are grouped as follows: (1) single-sample-based models, (2) a statistical approach based on the observed (curved) relationship between 14C and δ13C data for the aquifer, and (3) the geochemical mass-balance approach that constructs adjustment models accounting for all the geochemical reactions known to occur along a groundwater flow path. This review discusses first the geochemical processes behind each of the single-sample-based models, followed by discussions of the statistical approach and the geochemical mass-balance approach. Finally, the applications, advantages and limitations of the three groups of models/approaches are discussed.The single-sample-based models constitute the prevailing use of 14C data in hydrogeology and hydrological studies. This is in part because the models are applied to an individual water sample to estimate the 14C age, therefore the measurement data are easily available. These models have been shown to provide realistic radiocarbon ages in many studies. However, they usually are limited to simple carbonate aquifers and selection of model may have significant effects on 14C0 often resulting in a wide range of estimates of 14C ages.Of the single-sample-based models, four are recommended for the estimation of 14C0 of DIC in groundwater: Pearson's model, (Ingerson and Pearson, 1964; Pearson and White, 1967), Han & Plummer's model (Han and Plummer, 2013), the IAEA model (Gonfiantini, 1972; Salem et al., 1980), and Oeschger's model (Geyh, 2000). These four models include all processes considered in single-sample-based models, and can be used in different ranges of

  3. Ground-water quality in the West Salt River Valley, Arizona, 1996-98: relations to hydrogeology, water use, and land use

    Science.gov (United States)

    Edmonds, Robert J.; Gellenbeck, Dorinda J.

    2002-01-01

    The U.S. Geological Survey collected and analyzed ground-water samples in the West Salt River Valley from 64 existing wells selected by a stratified-random procedure. Samples from an areally distributed group of 35 of these wells were used to characterize overall ground-water quality in the basin-fill aquifer. Analytes included the principal inorganic constituents, trace constituents, pesticides, and volatile organic compounds. Additional analytes were tritium, radon, and stable isotopes of hydrogen and oxygen. Analyses of replicate samples and blank samples provided evidence that the analyses of the ground-water samples were adequate for interpretation. The median concentration of dissolved solids in samples from the 35 wells was 560 milligrams per liter, which exceeded the U.S. Environmental Protection Agency Secondary Maximum Contaminant Level for drinking water. Eleven of the 35 samples had a nitrate concentration (as nitrogen) that exceeded the U.S. Environmental Protection Agency Maximum Contaminant Level for drinking water of 10 milligrams per liter. Pesticides were detected in eight samples; concentrations were below the Maximum Contaminant Levels. Deethylatrazine was most commonly detected. The pesticides were detected in samples from wells in agricultural or urban areas that have been irrigated. Concentrations of all trace constituents, except arsenic, were less than the Maximum Contaminant Levels. The concentration of arsenic exceeded the Maximum Contaminant Level of 50 micrograms per liter in two samples. Nine monitoring wells were constructed in an area near Buckeye to assess the effects of agricultural land use on shallow ground water. The median concentration of dissolved solids was 3,340 milligrams per liter in samples collected from these wells in August 1997. The nitrate concentration (as nitrogen) exceeded the Maximum Contaminant Level (10 milligrams per liter) in samples from eight of the nine monitoring wells in August 1997 and again in

  4. Modeling the Impact of Cracking in Low Permeability Layers in a Groundwater Contamination Source Zone on Dissolved Contaminant Fate and Transport

    Science.gov (United States)

    Sievers, K. W.; Goltz, M. N.; Huang, J.; Demond, A. H.

    2011-12-01

    Dense Non-Aqueous Phase Liquids (DNAPLs), which are chemicals and chemical mixtures that are heavier than and only slightly soluble in water, are a significant source of groundwater contamination. Even with the removal or destruction of most DNAPL mass, small amounts of remaining DNAPL can dissolve into flowing groundwater and continue as a contamination source for decades. One category of DNAPLs is the chlorinated aliphatic hydrocarbons (CAHs). CAHs, such as trichloroethylene and carbon tetrachloride, are found to contaminate groundwater at numerous DoD and industrial sites. DNAPLs move through soils and groundwater leaving behind residual separate phase contamination as well as pools sitting atop low permeability layers. Recently developed models are based on the assumption that dissolved CAHs diffuse slowly from pooled DNAPL into the low permeability layers. Subsequently, when the DNAPL pools and residual DNAPL are depleted, perhaps as a result of a remediation effort, the dissolved CAHs in these low permeability layers still remain to serve as long-term sources of contamination, due to so-called "back diffusion." These recently developed models assume that transport in the low permeability zones is strictly diffusive; however field observations suggest that more DNAPL and/or dissolved CAH is stored in the low permeability zones than can be explained on the basis of diffusion alone. One explanation for these field observations is that there is enhanced transport of dissolved CAHs and/or DNAPL into the low permeability layers due to cracking. Cracks may allow for advective flow of water contaminated with dissolved CAHs into the layer as well as possible movement of pure phase DNAPL into the layer. In this study, a multiphase numerical flow and transport model is employed in a dual domain (high and low permeability layers) to investigate the impact of cracking on DNAPL and CAH movement. Using literature values, the crack geometry and spacing was varied to model

  5. Characterization of the structure, clean-sand percentage, dissolved-solids concentrations, and estimated quantity of groundwater in the Upper Cretaceous Nacatoch Sand and Tokio Formation, Arkansas

    Science.gov (United States)

    Gillip, Jonathan A.

    2014-01-01

    The West Gulf Coastal Plain, Mississippi embayment, and underlying Cretaceous aquifers are rich in water resources; however, large parts of the aquifers are largely unusable because of large concentrations of dissolved solids. Cretaceous aquifers are known to have large concentrations of salinity in some parts of Arkansas. The Nacatoch Sand and the Tokio Formation of Upper Cretaceous age were chosen for investigation because these aquifers produce groundwater to wells near their outcrops and have large salinity concentrations away from their outcrop areas. Previous investigations have indicated that dissolved-solids concentrations of groundwater within the Nacatoch Sand, 2–20 miles downdip from the outcrop, render the groundwater as unusable for purposes requiring freshwater. Groundwater within the Tokio Formation also exhibits large concentrations of dissolved solids downdip. Water-quality data showing elevated dissolved-solids concentrations are limited for these Cretaceous aquifers because other shallower aquifers are used for water supply. Although not suitable for many uses, large, unused amounts of saline groundwater are present in these aquifers. Historical borehole geophysical logs were used to determine the geologic and hydrogeologic properties of these Cretaceous aquifers, as well as the quality of the groundwater within the aquifers. Based on the interpretation of borehole geophysical logs, in Arkansas, the altitude of the top of the Nacatoch Sand ranges from more than 200 to less than -4,000 feet; the structural high occurs in the outcrop area and the structural low occurs in southeastern Arkansas near the Desha Basin structural feature. The thickness of the Nacatoch Sand ranges from 0 to over 550 feet. The minimum thickness occurs where the formation pinches out in the outcrop area, and the maximum thickness occurs in the southwestern corner of Arkansas. Other areas of large thickness include the area of the Desha Basin structural feature in

  6. INTEGRATED ASSESSMENTS OF POSSIBLE EFFECTS OF HYDROCARBON AND SALT WATER INTRUSION ON THE GROUNDWATER OF IGANMU AREA OF LAGOSMETROPOLIS, SOUTHWESTERN NIGERIA

    Directory of Open Access Journals (Sweden)

    Adetayo F. Adetayo F.

    2010-06-01

    Full Text Available Vertical electrical sounding (VES and Induced Polarisation (IP methods of geophysical survey were incorporated with  physiochemical analysis of well water samples to determine vertical extent of petroleum-product contamination in subsurface soils and groundwater from bulk-fuel storage and distribution terminals in Iganmu area of Lagos. Interpreted results of VES and IP revealed four geoelectric layers. Clay with resistivity and IP values ranging from 1.5 - 14 m and 50 - 400mV/V respectively was encountered at the last layer penetrated by the survey except in four VES stations where the clay horizon was delineated at the third layer. This implies that subsurface aquifer is sealed by impervious layer which possibly prevents it from being contaminated by hydrocarbon and other refuse materials from the surface. Borehole log and electrical resistivity survey from a control site within the area were also incorporated with the geophysical measurements and these confirm lithologic similarity and the presence of a sealant above the aquifer layer. In addition to this, the results of the physical and geochemical analyses carried out on groundwater samples from shallow wells within the pack show very negligible level of hydrocarbon contamination which has no serious environmental implications on subsurface water in the area. However, electrical conductivity, salinity and TDS values obtained show high level of dissolved minerals (salts making the water highly saline and unsuitable for drinking being far above recommended values for drinking water. We thus inferred that Lagos lagoon must haveinvaded the aquifer in some places leading to high salinity observed.

  7. Dissolved radon and uranium in groundwater in a potential coal seam gas development region (Richmond River Catchment, Australia).

    Science.gov (United States)

    Atkins, Marnie L; Santos, Isaac R; Perkins, Anita; Maher, Damien T

    2016-04-01

    The extraction of unconventional gas resources such as shale and coal seam gas (CSG) is rapidly expanding globally and often prevents the opportunity for comprehensive baseline groundwater investigations prior to drilling. Unconventional gas extraction often targets geological layers with high naturally occurring radioactive materials (NORM) and extraction practices may possibly mobilise radionuclides into regional and local drinking water resources. Here, we establish baseline groundwater radon and uranium levels in shallow aquifers overlying a potential CSG target formation in the Richmond River Catchment, Australia. A total of 91 groundwater samples from six different geological units showed highly variable radon activities (0.14-20.33 Bq/L) and uranium levels (0.001-2.77 μg/L) which were well below the Australian Drinking Water Guideline values (radon; 100 Bq/L and uranium; 17 μg/L). Therefore, from a radon and uranium perspective, the regional groundwater does not pose health risks to consumers. Uranium could not explain the distribution of radon in groundwater. Relatively high radon activities (7.88 ± 0.83 Bq/L) in the fractured Lismore Basalt aquifer coincided with very low uranium concentrations (0.04 ± 0.02 μg/L). In the Quaternary Sediments aquifers, a positive correlation between U and HCO3(-) (r(2) = 0.49, p groundwater investigations.

  8. Geochemical, isotopic, and dissolved gas characteristics of groundwater in a fractured crystalline-rock aquifer, Savage Municipal Well Superfund site, Milford, New Hampshire, 2011

    Science.gov (United States)

    Harte, Philip T.

    2013-01-01

    residential-supply wells (as of 2012). However, part of assessing the potential for PCE transport involves understanding the origin of the groundwater in the monitoring and residential wells. One of the tools in delineating the movement of groundwater to wells, particularly in complex, highly heterogeneous fractured-rock aquifers, is the understanding of the geochemical and isotopic composition of groundwater (Lipfert and Reeve, 2004; Harte and others, 2012). This report summarizes findings from analyses of geochemical, isotopic, and dissolved gas characteristics of groundwater. Samples of groundwater were collected in 2011 from monitoring wells and nearby residential-supply wells in proximity to OU1.

  9. High Frequency Monitoring of the Quantity and Quality of Dissolved Organic Matter Flux Between Salt Marshes and Plum Island Sound, MA

    Science.gov (United States)

    Zhao, Y.; Raymond, P.

    2012-12-01

    Salt marshes are highly productive continental margin ecosystems, due to abundant solar radiation, water, and nutrients provided by tidal water. The unique bi-directional water movement introduced by tidal effect has a major impact on the formation and productivity of salt marsh and the material exchange between salt marsh and adjacent estuary. As a major term in carbon, energy, and nutrient budget for aquatic ecosystem, dissolved organic matter (DOM) has broad impact on food webs, carbon cycle, and nutrient retention/release. The frequency and period of DOM measurement is greatly increased by the use of reagent-free, low-cost, and reliable measurement with fluorescent and UV sensors measuring the chromophoric fraction of total DOM. Although fluorescent sensors can only measure concentration, UV absorbance in a wide spectral range (200nm-380nm) could potentially provide information on DOM composition. With the help of accurate direct real time water flux measurement and lab analysis of lability, DON, and 3D excitation emission matrix spectroscopy (EEMs), a database of DOM quantity and quality exchanged between several comparative salt marshes and Plum Island Sound, MA could be established to study the dynamics of DOM behavior in the salt marsh-estuary system. Understanding DOM source and fate is very important for evaluating the role of salt marsh in the carbon cycle and food web in coastal and global scale because coastal carbon cycling represents up to 21% of the ocean's primary production (Jahnke 2008). In addition, the approaches outlined in this proposal have broad applicability to study DOM quantity and quality in the material exchange theme between systems.

  10. Gradual adaptation to salt and dissolved oxygen: Strategies to minimize adverse effect of salinity on aerobic granular sludge

    KAUST Repository

    Wang, Zhongwei

    2017-08-13

    Salinity can affect the performance of biological wastewater treatment in terms of nutrient removal. The effect of salt on aerobic granular sludge (AGS) process in terms of granulation and nutrient removal was examined in this study. Experiments were conducted to evaluate the effect of salt (15 g/L NaCl) on granule formation and nutrient removal in AGS system started with flocculent sludge and operated at DO of 2.5 mg/L (phase I). In addition, experiments were conducted to evaluate the effect of gradually increasing the salt concentration (2.5 g/L to 15 g/L NaCl) or increasing the DO level (2.5 mg/L to 8 mg/L) on nutrient removal in AGS system started with granular sludge (phase II) taken from an AGS reactor performing well in terms of N and P removal. Although the addition of salt in phase I did not affect the granulation process, it significantly affected nutrient removal due to inhibition of ammonia oxidizing bacteria (AOB) and phosphate accumulating organisms (PAOs). Increasing the DO to 8 mg/L or adapting granules by gradually increasing the salt concentration minimized the adverse effect of salt on nitrification (phase II). However, these strategies were not successful for mitigating the effect of salt on biological phosphorus removal. No nitrite accumulation occurred in all the reactors suggesting that inhibition of biological phosphorus removal was not due to the accumulation of nitrite as previously reported. Also, glycogen accumulating organisms were shown to be more tolerant to salt than PAO II, which was the dominant PAO clade detected in this study. Future studies comparing the salinity tolerance of different PAO clades are needed to further elucidate the effect of salt on PAOs.

  11. Differential effects of dissolved organic carbon upon re-entrainment and surface properties of groundwater bacteria and bacteria-sized microspheres during transport through a contaminated, sandy aquifer

    Science.gov (United States)

    Harvey, R.W.; Metge, D.W.; Mohanram, A.; Gao, X.; Chorover, J.

    2011-01-01

    Injection-and-recovery studies involving a contaminated, sandy aquifer (Cape Cod, Massachusetts) were conducted to assess the relative susceptibility for in situ re-entrainment of attached groundwater bacteria (Pseudomonas stuzeri ML2, and uncultured, native bacteria) and carboxylate-modified microspheres (0.2 and 1.0 ??m diameters). Different patterns of re-entrainment were evident for the two colloids in response to subsequent injections of groundwater (hydrodynamic perturbation), deionized water (ionic strength alteration), 77 ??M linear alkylbenzene sulfonates (LAS, anionic surfactant), and 76 ??M Tween 80 (polyoxyethylene sorbitan monooleate, a very hydrophobic nonionic surfactant). An injection of deionized water was more effective in causing detachment of micrsopheres than were either of the surfactants, consistent with the more electrostatic nature of microsphere's attachment, their extreme hydrophilicity (hydrophilicity index, HI, of 0.99), and negative charge (zeta potentials, ??, of -44 to -49 mv). In contrast, Tween 80 was considerably more effective in re-entraining the more-hydrophobic native bacteria. Both the hydrophilicities and zeta potentials of the native bacteria were highly sensitive to and linearly correlated with levels of groundwater dissolved organic carbon (DOC), which varied modestly from 0.6 to 1.3 mg L-1. The most hydrophilic (0.52 HI) and negatively charged (?? -38.1 mv) indigenous bacteria were associated with the lowest DOC. FTIR spectra indicated the latter community had the highest average density of surface carboxyl groups. In contrast, differences in groundwater (DOC) had no measurable effect on hydrophilicity of the bacteria-sized microspheres and only a minor effect on their ??. These findings suggest that microspheres may not be very good surrogates for bacteria in field-scale transport studies and that adaptive (biological) changes in bacterial surface characteristics may need to be considered where there is longer

  12. Importance of dissolved organic carbon flux through submarine groundwater discharge to the coastal ocean: Results from Masan Bay, the southern coast of Korea

    Science.gov (United States)

    Oh, Yong Hwa; Lee, Yong-Woo; Park, Sang Rul; Kim, Tae-Hoon

    2017-09-01

    In order to estimate the fluxes of dissolved organic carbon (DOC) through submarine groundwater discharge (SGD), salinity and DOC concentrations in groundwater, stream water, and seawater were investigated in May 2006 and 2007 (dry season) and August 2006 (wet season) in Masan Bay, Korea. In both seasons, the average concentrations of DOC in groundwater (139 ± 23 μM in May and 113 ± 18 μM in August) were relatively lower than those in stream water (284 ± 104 μM in May and 150 ± 36 μM in August) but similar to those of the bay water (149 ± 17 μM in May and 117 ± 13 μM in August). The DOC concentrations in groundwater, stream water, and seawater showed negative relationships with salinity, but those in the surface bay water were observed above the theoretical mixing line, indicating that DOC may be produced by in situ primary production in this bay. Based on a simple DOC mass balance model, SGD-derived DOC fluxes in Masan Bay were estimated to be 6.7 × 105 mol d- 1 in the dry season and 6.4 × 105 mol d- 1 in the wet season, showing no remarkable seasonal variation. The DOC fluxes through SGD in Masan Bay accounted for approximately 65% of the total input fluxes. This result suggests that the DOC flux through SGD can be the most important source of DOC in this bay, and SGD may play an important role in carbon budget and biogeochemistry in coastal areas.

  13. Investigating the effect of landfill leachates on the characteristics of dissolved organic matter in groundwater using excitation-emission matrix fluorescence spectra coupled with fluorescence regional integration and self-organizing map.

    Science.gov (United States)

    He, Xiao-Song; Fan, Qin-Dong

    2016-11-01

    For the purpose of investigating the effect of landfill leachate on the characteristics of organic matter in groundwater, groundwater samples were collected near and in a landfill site, and dissolved organic matter (DOM) was extracted from the groundwater samples and characterized by excitation-emission matrix (EEM) fluorescence spectra combined with fluorescence regional integration (FRI) and self-organizing map (SOM). The results showed that the groundwater DOM comprised humic-, fulvic-, and protein-like substances. The concentration of humic-like matter showed no obvious variation for all groundwater except the sample collected in the landfill site. Fulvic-like substance content decreased when the groundwater was polluted by landfill leachates. There were two kinds of protein-like matter in the groundwater. One kind was bound to humic-like substances, and its content did not change along with groundwater pollution. However, the other kind was present as "free" molecules or else bound in proteins, and its concentration increased significantly when the groundwater was polluted by landfill leachates. The FRI and SOM methods both can characterize the composition and evolution of DOM in the groundwater. However, the SOM analysis can identify whether protein-like moieties was bound to humic-like matter.

  14. Field Tests of “In-Situ” Remediation of Groundwater From Dissolved Mercury Utilizing Sulfate Reducing Bacteria

    Science.gov (United States)

    Field tests of biologically active filters have been conducted at groundwater mercury pollution site in Pavlodar, Kazakhstan. The biofilters represented cultures of sulfate-reducing bacteria (SRB) immobilized on claydite imbedded in wells drilled down to basalt clay layer (14-17 ...

  15. Inter-comparison exercises on dissolved gases for groundwater dating (GDAT 2012) : analytical uncertainties, apparent ages and other derived parameters.

    Science.gov (United States)

    Labasque, Thierry; Aquilina, Luc; Visser, Ate; Vergnaud, Virginie

    2014-05-01

    An inter-laboratory comparison exercise dedicated to environmental tracers used for groundwater dating was organized in 2012 in France. The goal was to compare sampling and analytical protocols through results obtained by the community of groundwater dating laboratories. Sampling and analytical protocols were compared through three different exercises on various supports : (1) on groundwater from a homogeneous aquifer, (2) on groundwater from a fractured heterogeneous aquifer and (3) on an air standard. The two tests allowed 31 Laboratories from 14 countries to compare their protocols for both sampling and analyses. It allows discussing the uncertainties related to sampling protocols issuing from each laboratory methods. The results show a good agreement between laboratories on the aquifers and the air standard. The dispersion of SF6 results in air standard is low (rsd 2%) compared to CFCs (rsd 3 to 7%), even if its concentration is two orders of magnitude lower. Results obtained in recent groundwater (recharge after 1980) show that the uncertainty on groundwater dating with SF6 is between 3 and 4 years. This large uncertainty is mainly due to sampling and/or analytical problems. For CFCs, uncertainties obtained over all the laboratories are less than 2 years for groundwater with recharge between 1965 and 1996. The goal of the inter-laboratory comparison exercise was also to quantify the analytical uncertainty of the 3H and noble gas measurements and to assess whether they meet the requirements for 3H/3He dating and noble gas paleotemperature reconstruction. The reproducibility of the tritium measurements was 13.5%. The reproducibility of the 3He/4He ratio and 4He, Ne, Ar, Kr and Xe concentrations was 1.4%, 1.8%, 1.5%, 2.2%, 2.9%, and 2.4%. The propagated uncertainty of the tritium and noble gas measurements meets the desired precision for typical 3H/3He dating applications. However, the measurement uncertainties for the noble gas concentrations are insufficient to

  16. How significant is submarine groundwater discharge and its associated dissolved inorganic carbon in a river-dominated shelf system-the northern South China Sea?

    Directory of Open Access Journals (Sweden)

    Q. Liu

    2011-12-01

    Full Text Available In order to assess the role of submarine groundwater discharge (SGD and its impact on the carbonate system on the northern South China Sea (NSCS shelf, we measured seawater concentrations of four radium isotopes 223,224,226,228Ra along with carbon dioxide parameters in June–July, 2008. Complementary groundwater sampling was conducted in coastal areas in December 2008 and October 2010 to constrain the groundwater end-members. The distribution of Ra isotopes in the NSCS was largely controlled by the Pearl River plume and coastal upwelling. Long-lived Ra isotopes (228Ra and 226Ra were enriched in the river plume but low in the offshore surface water and subsurface water/upwelling zone. In contrast, short-lived Ra isotopes (224Ra and 223Ra were elevated in the subsurface water/upwelling zone as well as the river plume but depleted in the offshore surface water. In order to quantify SGD, we adopted two independent mathematical approaches. Using a three end-member mixing model with total alkalinity (TAlk and Ra isotopes, we derived a SGD flux into the NSCS shelf of 2.3–3.7 ×108 m3 d−1. Our second approach involved a simple mass balance of 228Ra and 226Ra and resulted in a first order but consistent SGD rate estimate of 2.8–4.5 × 108 m3 d−1. These fluxes were equivalent to 13–25 % of the Pearl River discharge, but the source of the SGD is mostly recirculated seawater. Despite the relatively small SGD volume flow compared to the river, the associated material fluxes were substantial given the elevated concentrations of dissolved inorganic solutes. In this case, dissolved inorganic carbon (DIC flux through SGD was 266–520 × 109 mol yr−1, which was ~44–73 % of the riverine DIC export flux. Given our estimates of the groundwater-derived phosphate flux, SGD may be

  17. CONTAMINATION OF GROUNDWATER IN SRIKAKULAM COASTAL BELT DUE TO SALT WATER INTRUSION

    Directory of Open Access Journals (Sweden)

    S. Chandra Mouli

    2011-02-01

    Full Text Available Many urban centers of the country are located on the coastal tract apart from thousands of villages and industrial settlements. Water resources in coastal areas assume a special significance since anydevelopmental activity will largely depend upon availability of fresh water to meet domestic, industrial and agricultural requirements.Thisincreases the dependency upon groundwater for meeting the freshwater demand. As the region is close to the coast, the variations in the levels of water table due to excess withdrawals from wells and bore wells will cause the intrusion of seawater into the groundwater. In the present paper deals with the study of saltwater intrusion in the coastal tract of Srikakulam district, on an areal basis. From the results obtained the variation in the effect of contamination with respect to distance from shore is studied and a comparison of the contamination in open wells and bore wells is also carried out.

  18. Methods for evaluating temporal groundwater quality data and results of decadal-scale changes in chloride, dissolved solids, and nitrate concentrations in groundwater in the United States, 1988-2010

    Science.gov (United States)

    Lindsey, Bruce D.; Rupert, Michael G.

    2012-01-01

    Decadal-scale changes in groundwater quality were evaluated by the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. Samples of groundwater collected from wells during 1988-2000 - a first sampling event representing the decade ending the 20th century - were compared on a pair-wise basis to samples from the same wells collected during 2001-2010 - a second sampling event representing the decade beginning the 21st century. The data set consists of samples from 1,236 wells in 56 well networks, representing major aquifers and urban and agricultural land-use areas, with analytical results for chloride, dissolved solids, and nitrate. Statistical analysis was done on a network basis rather than by individual wells. Although spanning slightly more or less than a 10-year period, the two-sample comparison between the first and second sampling events is referred to as an analysis of decadal-scale change based on a step-trend analysis. The 22 principal aquifers represented by these 56 networks account for nearly 80 percent of the estimated withdrawals of groundwater used for drinking-water supply in the Nation. Well networks where decadal-scale changes in concentrations were statistically significant were identified using the Wilcoxon-Pratt signed-rank test. For the statistical analysis of chloride, dissolved solids, and nitrate concentrations at the network level, more than half revealed no statistically significant change over the decadal period. However, for networks that had statistically significant changes, increased concentrations outnumbered decreased concentrations by a large margin. Statistically significant increases of chloride concentrations were identified for 43 percent of 56 networks. Dissolved solids concentrations increased significantly in 41 percent of the 54 networks with dissolved solids data, and nitrate concentrations increased significantly in 23 percent of 56 networks. At least one of the three - chloride, dissolved solids, or

  19. Measurement of dissolved Cs-137 in stream water, soil water and groundwater at Headwater Forested Catchment in Fukushima after Fukushima Dai-ichi Nuclear Power Plant Accident

    Science.gov (United States)

    Iwagami, Sho; Tsujimura, Maki; Onda, Yuichi; Sakakibara, Koichi; Konuma, Ryohei; Sato, Yutaro

    2016-04-01

    Radiocesium migration from headwater forested catchment is important perception as output from the forest which is also input to the subsequent various land use and downstream rivers after Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. In this study, dissolved Cs-137 concentration of stream water, soil water and groundwater were measured. Observations were conducted at headwater catchment in Yamakiya district, located 35 km northwest of FDNPP from April 2014 to November 2015. Stream water discharge was monitored and stream water samples were taken at main channel and sub channel. Stream water discharge was monitored by combination of parshallflume and v-notch weir. Stream water was sampled manually at steady state condition in 3-4 month interval and also intense few hours interval sampling were conducted during rainfall events using automated water sampler. Around the sub channel, it is found that there is a regularly saturated area at the bottom of the slope, temporary saturated area which saturate during the rainy season in summer and regularly dry area. 6 interval cameras were installed to monitor the changing situation of saturated area. Suction lysimeters were installed at three areas (regularly saturated area, temporary saturated area and dry area) for sampling soil water in depth of 0.1 m and 0.3 m. Boreholes were installed at three points along the sub channel. Three boreholes with depth of 3 m, 5 m and 10 m were installed at temporary saturated area, 20 m upstream of sub channel weir. Another three boreholes with depth of 3 m, 5 m and 10 m were installed at dry area, 40 m upstream of sub channel weir. And a borehole with depth of 20 m was installed at ridge of sub catchment, 52 m upstream of sub channel weir. Groundwater was sampled by electrically powered pump and groundwater level was monitored. Also suction-free lysimeter was installed at temporary saturated area for sampling the near surface subsurface water. Soil water samples were collected

  20. Human health risk assessment of dissolved metals in groundwater and surface waters in the Melen watershed, Turkey.

    Science.gov (United States)

    Çelebi, Ahmet; Sengörür, Bülent; Kløve, Bjørn

    2014-01-01

    Determination of metal risk levels in potable water and their effects on human health are vital in assessment of water resources. Risk assessment of metals to human health in a watershed, which has not been studied before, is the main objective of the present study. Surface and groundwater sampling was carried out between September 2010 and August 2011 in the Melen Watershed, Turkey, an important drinking water resource for millions of people. Metals were analyzed in the laboratory using inductively coupled plasma. Of the 26 different metals monitored, Al, B, Ba, Cr, Cu, Fe, Mn, Mo and V were found in surface water and As, B, Ba, Cr, Cu, Mn, Mo, V and Zn in groundwater. In groundwater, unitless hazard quotient (HQ) values were 6 for As, 2.7 for Mn and 1 for Zn, while in surface water all metals were below the risk level (HQ watersheds can pose a risk to human health and that potential carcinogenic impacts should receive more attention.

  1. Radiocarbon dating of dissolved inorganic carbon in groundwater from confined parts of the Upper Floridan aquifer, Florida, USA

    Science.gov (United States)

    Plummer, Niel; Sprinkle, Craig

    2001-03-01

    Geochemical reaction models were evaluated to improve radiocarbon dating of dissolved inorganic carbon (DIC) in groundwater from confined parts of the Upper Floridan aquifer in central and northeastern Florida, USA. The predominant geochemical reactions affecting the 14C activity of DIC include (1) dissolution of dolomite and anhydrite with calcite precipitation (dedolomitization), (2) sulfate reduction accompanying microbial degradation of organic carbon, (3) recrystallization of calcite (isotopic exchange), and (4) mixing of fresh water with as much as 7% saline water in some coastal areas. The calculated cumulative net mineral transfers are negligibly small in upgradient parts of the aquifer and increase significantly in downgradient parts of the aquifer, reflecting, at least in part, upward leakage from the Lower Floridan aquifer and circulation that contacted middle confining units in the Floridan aquifer system. The adjusted radiocarbon ages are independent of flow path and represent travel times of water from the recharge area to the sample point in the aquifer. Downgradient from Polk City (adjusted age 1.7 ka) and Keystone Heights (adjusted age 0.4 ka), 14 of the 22 waters have adjusted 14C ages of 20-30 ka, indicating that most of the fresh-water resource in the Upper Floridan aquifer today was recharged during the last glacial period. All of the paleowaters are enriched in 18O and 2H relative to modern infiltration, with maximum enrichment in δ18O of approximately 2.0‰. Résumé. Les modèles de réactions géochimiques ont été évalués afin de tester la datation par le radiocarbone du carbone minéral dissous (CMD) des eaux souterraines dans les parties captives de la nappe supérieure de Floride, en Floride centrale et nord-orientale (États-Unis). Les réactions géochimiques prédominantes affectant l'activité en 14C du CMD comprennent (1) la dissolution de la dolomite et de l'anhydrite accompagnée de la précipitation de la calcite (d

  2. Investigation of sulphide in core drilled boreholes KLX06, KAS03 and KAS09 at Laxemar and Aespoe Chemical-, microbiological- and dissolved gas data from groundwater in four borehole sections

    Energy Technology Data Exchange (ETDEWEB)

    Rosdahl, Anette (Geosigma AB (Sweden)); Pedersen, Karsten; Hallbeck, Lotta (Microbial Analytics Sweden AB (Sweden)); Wallin, Bill (Geokema AB (Sweden))

    2011-01-15

    This report describes a study performed during 2009 which focused on the production of sulphide (microbial sulphate reduction) in deep groundwater that was implemented in the core drilled boreholes KLX06, -475 to 482 meter above sea level, m a s l, KAS03,-97 to 241 and -613 to 984 m a s l, and KAS09, -96 to -125 m a s l, at Laxemar and Aspo. The study aimed to increase knowledge of background groundwater levels of sulphide and its variations in time and space through the analysis of sulphide and parameters related to sulphide production. Sampling of groundwater was conducted in three core drilled boreholes of varying age as time series with continuous pumping and as single samples. The analysis program covered chemical parameters (pH, chloride, sulphate, iron, and organic carbon), dissolved gas composition, stable isotopes in groundwater (delta2H, delta18O, delta34S, delta13C), stable isotopes of gaseous compounds (delta2H, delta13C, delta18O), microbiological parameters (sulphate- and iron reducing bacteria, SRB and IRB), phthalates and low molecular mass organic acids (LMMOA). The sampling in KLX06 was carried out as time series with a 9 week pause in pumping. When the water volume discharged was about 150 times that of the packer-isolated borehole section, sulphides decreased from 7 mg L-1 to 0.05 mg L-1 and the salinity increased from 740 to 1,480 mg L-1. After a 9 weeks pause in pumping, the sulphide concentration and salinity again approached the original values, i.e. 7 mg L-1 of sulphide and 450 mg L-1 of chloride. The SRB and IRB showed high concentrations that were reduced during pumping in the borehole. The water in the standpipe which has a different water composition than the groundwater, also showed similar high concentrations of sulphide and SRB. The standpipe is a plastic pipe in the wider upper part of the borehole; connected with the tube from the packer of the borehole section and used to accommodate a filter and a groundwater pump when collecting

  3. Investigation of sulphide in core drilled boreholes KLX06, KAS03 and KAS09 at Laxemar and Aespoe Chemical-, microbiological- and dissolved gas data from groundwater in four borehole sections

    Energy Technology Data Exchange (ETDEWEB)

    Rosdahl, Anette (Geosigma AB (Sweden)); Pedersen, Karsten; Hallbeck, Lotta (Microbial Analytics Sweden AB (Sweden)); Wallin, Bill (Geokema AB (Sweden))

    2011-01-15

    This report describes a study performed during 2009 which focused on the production of sulphide (microbial sulphate reduction) in deep groundwater that was implemented in the core drilled boreholes KLX06, -475 to 482 meter above sea level, m a s l, KAS03,-97 to 241 and -613 to 984 m a s l, and KAS09, -96 to -125 m a s l, at Laxemar and Aspo. The study aimed to increase knowledge of background groundwater levels of sulphide and its variations in time and space through the analysis of sulphide and parameters related to sulphide production. Sampling of groundwater was conducted in three core drilled boreholes of varying age as time series with continuous pumping and as single samples. The analysis program covered chemical parameters (pH, chloride, sulphate, iron, and organic carbon), dissolved gas composition, stable isotopes in groundwater (delta2H, delta18O, delta34S, delta13C), stable isotopes of gaseous compounds (delta2H, delta13C, delta18O), microbiological parameters (sulphate- and iron reducing bacteria, SRB and IRB), phthalates and low molecular mass organic acids (LMMOA). The sampling in KLX06 was carried out as time series with a 9 week pause in pumping. When the water volume discharged was about 150 times that of the packer-isolated borehole section, sulphides decreased from 7 mg L-1 to 0.05 mg L-1 and the salinity increased from 740 to 1,480 mg L-1. After a 9 weeks pause in pumping, the sulphide concentration and salinity again approached the original values, i.e. 7 mg L-1 of sulphide and 450 mg L-1 of chloride. The SRB and IRB showed high concentrations that were reduced during pumping in the borehole. The water in the standpipe which has a different water composition than the groundwater, also showed similar high concentrations of sulphide and SRB. The standpipe is a plastic pipe in the wider upper part of the borehole; connected with the tube from the packer of the borehole section and used to accommodate a filter and a groundwater pump when collecting

  4. Enrichment of fluoride in groundwater under the impact of saline water intrusion at the salt lake area of Yuncheng basin, northern China

    Science.gov (United States)

    Gao, Xubo; Wang, Yanxin; Li, Yilian; Guo, Qinghai

    2007-12-01

    Long-term intake of high-fluoride groundwater causes endemic fluorosis. This study, for the first time, discovered that the salt lake water intrusion into neighboring shallow aquifers might result in elevation of fluoride content of the groundwater. Two cross-sections along the groundwater flow paths were selected to study the geochemical processes controlling fluoride concentration in Yuncheng basin, northern China. There are two major reasons for the observed elevation of fluoride content: one is the direct contribution of the saline water; the other is the undersaturation of the groundwater with respect to fluorite due to salt water intrusion, which appears to be more important reason. The processes of the fluorine activity reduction and the change of Na/Ca ratio in groundwater induced by the intrusion of saline water favor further dissolution of fluorine-bearing mineral, and it was modeled using PHREEQC. With the increase in Na concentration (by adding NaCl or Na2SO4 as Na source, calcium content kept invariable), the increase of NaF concentration was rapid at first and then became slower; and the concentrations of HF, HF{2/-}, CaF+, and MgF+ were continuously decreasing. The geochemical conditions in the study area are advantageous to the complexation of F- with Na+ and the decline of saturation index of CaF2, regardless of the water type (Cl-Na or SO4-Na type water).

  5. Spatial analysis of groundwater electrical conductivity using ordinary kriging and artificial intelligence methods (Case study: Maharlu-Bakhtegan and Tashk salt lakes basin, Iran)

    Science.gov (United States)

    Ghader, Fatemeh; Aljoumani, Basem; Tröger, Uwe

    2017-04-01

    The main resources of fresh water are the groundwater. In Iran, the quality and quantity of groundwater is affected significantly by rapid population growth and unsustainable water management in the agricultural and industrial sectors. in Maharlu-Bakhtegan and Tashk salt lakes basin, the overexploitation of groundwater for irrigation purpose caused the salt water intrusion from the lakes to the area's aquifers, moreover, the basin is located in south of Iran with semiarid climate, faces a significant decline in rainfall. All these reasons cause the degradation of ground water quality. For this study, geographical coordinates of 406 observation wells will be defined as inputs and groundwater electrical conductivities (EC) will be set as output. Ordinary kriging (OK) and artificial neural networks (ANN) will be investigated for modeling groundwater salinity. Eighty percent of data will be randomly selected to train and develop mentioned models and twenty percent of data will be used for testing and validating. Finally, the outputs of models will be compared with the corresponding measured values in observation wells.

  6. [Groundwater].

    Science.gov (United States)

    González De Posada, Francisco

    2012-01-01

    From the perspective of Hydrogeology, the concept and an introductory general typology of groundwater are established. From the perspective of Geotechnical Engineering works, the physical and mathematical equations of the hydraulics of permeable materials, which are implemented, by electric analogical simulation, to two unique cases of global importance, are considered: the bailing during the construction of the dry dock of the "new shipyard of the Bahia de Cádiz" and the waterproofing of the "Hatillo dam" in the Dominican Republic. From a physical fundamental perspective, the theories which are the subset of "analogical physical theories of Fourier type transport" are related, among which the one constituted by the laws of Adolf Fick in physiology occupies a historic role of some relevance. And finally, as a philosophical abstraction of so much useful mathematical process, the one which is called "the Galilean principle of the mathematical design of the Nature" is dealt with.

  7. Evaluation of high-frequency mean streamwater transit-time estimates using groundwater age and dissolved silica concentrations in a small forested watershed

    Science.gov (United States)

    Peters, Norman E.; Burns, Douglas A.; Aulenbach, Brent T.

    2014-01-01

    Many previous investigations of mean streamwater transit times (MTT) have been limited by an inability to quantify the MTT dynamics. Here, we draw on (1) a linear relation (r 2 = 0.97) between groundwater 3H/3He ages and dissolved silica (Si) concentrations, combined with (2) predicted streamwater Si concentrations from a multiple-regression relation (R 2 = 0.87) to estimate MTT at 5-min intervals for a 23-year time series of streamflow [water year (WY) 1986 through 2008] at the Panola Mountain Research Watershed, Georgia. The time-based average MTT derived from the 5-min data was ~8.4 ± 2.9 years and the volume-weighted (VW) MTT was ~4.7 years for the study period, reflecting the importance of younger runoff water during high flow. The 5-min MTTs are normally distributed and ranged from 0 to 15 years. Monthly VW MTTs averaged 7.0 ± 3.3 years and ranged from 4 to 6 years during winter and 8–10 years during summer. The annual VW MTTs averaged 5.6 ± 2.0 years and ranged from ~5 years during wet years (2003 and 2005) to >10 years during dry years (2002 and 2008). Stormflows are composed of much younger water than baseflows, and although stormflow only occurs ~17 % of the time, this runoff fraction contributed 39 % of the runoff during the 23-year study period. Combining the 23-year VW MTT (including stormflow) with the annual average baseflow for the period (~212 mm) indicates that active groundwater storage is ~1,000 mm. However, the groundwater storage ranged from 1,040 to 1,950 mm using WY baseflow and WY VW MTT. The approach described herein may be applicable to other watersheds underlain by granitoid bedrock, where weathering is the dominant control on Si concentrations in soils, groundwater, and streamwater.

  8. Removal of inorganic mercury and methylmercury from surface waters following coagulation of dissolved organic matter with metal-based salts

    Science.gov (United States)

    Henneberry, Y.K.; Kraus, T.E.C.; Fleck, J.A.; Krabbenhoft, D.P.; Bachand, P.M.; Horwath, W.R.

    2011-01-01

    The presence of inorganic mercury (IHg) and methylmercury (MeHg) in surface waters is a health concern worldwide. This study assessed the removal potential use of metal-based coagulants as a means to remove both dissolved IHg and MeHg from natural waters and provides information regarding the importance of Hg associations with the dissolved organic matter (DOM) fraction and metal hydroxides. Previous research indicated coagulants were not effective at removing Hg from solution; however these studies used high concentrations of Hg and did not reflect naturally occurring concentrations of Hg. In this study, water collected from an agricultural drain in the Sacramento-San Joaquin Delta was filtered to isolate the dissolved organic matter (DOM) fraction. The DOM was then treated with a range of coagulant doses to determine the efficacy of removing all forms of Hg from solution. Three industrial-grade coagulants were tested: ferric chloride, ferric sulfate, and polyaluminum chloride. Coagulation removed up to 85% of DOM from solution. In the absence of DOM, all three coagulants released IHg into solution, however in the presence of DOM the coagulants removed up to 97% of IHg and 80% of MeHg. Results suggest that the removal of Hg is mediated by DOM-coagulant interactions. There was a preferential association of IHg with the more aromatic, higher molecular weight fraction of DOM but no such relationship was found for MeHg. This study offers new fundamental insights regarding large-scale removal of Hg at environmentally relevant regarding large-scale removal of Hg at environmentally relevant concentrations.

  9. Attractive forces between hydrophobic solid surfaces measured by AFM on the first approach in salt solutions and in the presence of dissolved gases.

    Science.gov (United States)

    Azadi, Mehdi; Nguyen, Anh V; Yakubov, Gleb E

    2015-02-17

    Interfacial gas enrichment of dissolved gases (IGE) has been shown to cover hydrophobic solid surfaces in water. The atomic force microscopy (AFM) data has recently been supported by molecular dynamics simulation. It was demonstrated that IGE is responsible for the unexpected stability and large contact angle of gaseous nanobubbles at the hydrophobic solid-water interface. Here we provide further evidence of the significant effect of IGE on an attractive force between hydrophobic solid surfaces in water. The force in the presence of dissolved gas, i.e., in aerated and nonaerated NaCl solutions (up to 4 M), was measured by the AFM colloidal probe technique. The effect of nanobubble bridging on the attractive force was minimized or eliminated by measuring forces on the first approach of the AFM probe toward the flat hydrophobic surface and by using high salt concentrations to reduce gas solubility. Our results confirm the presence of three types of forces, two of which are long-range attractive forces of capillary bridging origin as caused by either surface nanobubbles or gap-induced cavitation. The third type is a short-range attractive force observed in the absence of interfacial nanobubbles that is attributed to the IGE in the form of a dense gas layer (DGL) at hydrophobic surfaces. Such a force was found to increase with increasing gas saturation and to decrease with decreasing gas solubility.

  10. Groundwater cleanup by in-situ sparging. XIII. Random air channels for sparing of dissolved and nonaqueous phase volatiles

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, D.J.; Clarke, A.N. [Eckenfelder, Inc., Nashville, TN (United States); Kaminski, K.M.; Chang, E.Y. [Martin Luther King Magnet High School, Nashville, TN (United States)

    1997-12-01

    A mathematical model is developed to simulate the sparging of dissolved volatile organic compounds (VOCs) and nonaqueous phase liquid (NAPL) from contaminated aquifers. The sparging air moves through the aquifer in persistent, random channels, to which VOC must move by diffusion/dispersion to be removed. The dependence of the rate of remediation on the various model parameters is investigated and some practical conclusions are reached regarding the operation of air sparging wells for aquifer remediation. VOCs of low water solubility (such as alkanes) and present as NAPL are found to be removed by air sparging much more slowly than VOCs of higher water solubility (such as benzene, toluene, ethylbenzene and xylenes) and present as NAPL, due to the very small maximum concentration gradients which can be maintained around droplets of the former. These small concentration gradients result in very slow rates of NAPL solution.

  11. Groundwater flow in an `underfit' carbonate aquifer in a semiarid climate: application of environmental tracers to the Salt Basin, New Mexico (USA)

    Science.gov (United States)

    Sigstedt, Sophia C.; Phillips, Fred M.; Ritchie, Andre B. O.

    2016-06-01

    The Salt Basin is a semiarid hydrologically closed drainage basin in southern New Mexico, USA. The aquifers in the basin consist largely of Permian limestone and dolomite. Groundwater flows from the high elevations (˜2,500 m) of the Sacramento Mountains south into the Salt Lakes, which are saline playas. The aquifer is `underfit' in the sense that depths to groundwater are great (˜300 m), implying that the aquifer could transmit much more water than it does. In this study, it is speculated that this characteristic is a result of a geologically recent reduction in recharge due to warming and drying at the end of the last glacial period. Water use is currently limited, but the basin has been proposed for large-scale groundwater extraction and export projects. Wells in the basin are of limited utility for hydraulic testing; therefore, the study focused on environmental tracers (major-ion geochemistry, stable isotopes of O, H, and C, and 14C dating) for basin analysis. The groundwater evolves from a Ca-HCO3 type water into a Ca-Mg (Na) - HCO3-Mg (Cl) water as it flows toward the center of the basin due to dedolomitization driven by gypsum dissolution. Carbon-14 ages corrected for dedolomitization ranged from less than 1,000 years in the recharge area to 19,000 years near the basin center. Stable isotopes are consistent with the presence of glacial-period recharge that is much less evaporated than modern. This supports the hypothesis that the underfit nature of the aquifer is a result of a geologically recent reduction in recharge.

  12. Dissolved inorganic nitrogen pools and surface flux under different brackish marsh vegetation types, common reed (Phragmites australis) and salt hay (Spartina patens)

    Science.gov (United States)

    Windham-Myers, L.

    2005-01-01

    The current expansion of Phragmites australis into the high marsh shortgrass (Spartina patens, Distichlis spicata) communities of eastern U.S. salt marshes provided an opportunity to identify the influence of vegetation types on pools and fluxes of dissolved inorganic nitrogen (DIN). Two brackish tidal marshes of the National Estuarine Research Reserve system were examined, Piermont Marsh of the Hudson River NERR in New York and Hog Island in the Jacques Coustaeu NERR of New Jersey. Pools of DIN in porewater and rates of DIN surface flux were compared in replicated pairs of recently-expanded P. australis and neighboring S. patens-dominated patches on the high marsh surface. Both marshes generally imported nitrate (NO3-) and exported ammonium (NH4+), such that overall DIN was exported. No differences in surface exchange of NO3- or NH4+ were observed between vegetation types. Depth-averaged porewater NH4+ concentrations over the entire growing season were 56% lower under P. australis than under S. patens (average 1.4 vs. 3.2 mg NH4+ L-1) with the most profound differences in November. Porewater profiles showed an accumulation of NH4+ at depth in S. patens and constant low concentrations in P. australis from the soil surface to 50 cm depth, with no significant differences in porewater salinity. Despite these profound differences in porewater, NH 4+ diffusion from soils of P. australis and S. patens were not measurably different, were similar to other published rates, and were well below estimated rates based on passive diffusion alone. Rapid adsorption and uptake by litter and microbes in surface soils of both communities may buffer NH4+ loss to flooding tides in both communities, thereby reducing the impact of P. australis invasion on NH4+ flux to flooding waters. ?? Springer 2005.

  13. Efficacy of controlled-release KMnO4 (CRP) for controlling dissolved TCE plume in groundwater: a large flow-tank study.

    Science.gov (United States)

    Lee, Byung Sun; Kim, Jeong Hee; Lee, Ki Churl; Kim, Yang Bin; Schwartz, Franklin W; Lee, Eung Seok; Woo, Nam Chil; Lee, Myoung Ki

    2009-02-01

    A well-based, reactive barrier system using controlled-release potassium permanganate (CRP system) was recently developed as a long-term treatment option for dilute plumes of chlorinated solvents in groundwater. In this study, we performed large-scale (L x W x D = 8 m x 4 m x 2 m) flow-tank experiments to examine remedial efficacy of the CRP system. A total of 110 CRP rods (OD x L=5 cm x 150 cm) were used to construct a well-based CRP system (L x W x D = 3 m x 4 m x 1.5 m) comprising three discrete barriers installed at 1-m interval downstream. Natural sands having oxidant demand of 3.7 g MnO(4)(-)kg(-1) for 500 mg L(-1)MnO(4)(-) were used as porous media. After MnO(4)(-) concentrations were somewhat stabilized (0.5-6.0 mg L(-1)), trichloroethylene (TCE) plume was flowed through the flow-tank for 53 d by supplying 1.19 m(3)d(-1) of TCE solution. Mean initial TCE concentrations were 87 microg L(-1) for first 20 d and 172 microg L(-1) for the next 33 d. During TCE treatment, flow velocity (0.60md(-1)), pH (7.0-8.2), and concentrations of dissolved metals ([Al]=0.7 mg L(-1), [Fe]=0.01 mg L(-1)) showed little variations. The MnO(2)(s) contents in the sandy media measured after the TCE treatment ranged from 21 to 26 mg kg(-1), slightly increased from mean baseline value of 17 mg kg(-1). Strengths of the TCE plume considerably diminished by the CRP system. For the 87 microg L(-1) plume, TCE concentrations decreased by 38% (53), 67% (29), and 74% (23 microg L(-1)) after 1st, 2nd, and 3rd barriers, respectively. For the 172 microg L(-1) plume, TCE concentrations decreased by 27% (125), 46% (93), and 65% (61 microg L(-1)) after 1st, 2nd, and 3rd barriers, respectively. Incomplete destruction of TCE plume was attributed to the lack of lateral dispersion in the unpumped well-based barrier system. Development of delivery systems that can facilitate lateral spreading and mixing of permanganate with contaminant plume is warranted.

  14. {sup 34}S and {sup 18}O in dissolved sulfate as tracers of hydrogeochemical evolution of the Triassic carbonate aquifer exposed to intense groundwater exploitation (Olkusz-Zawiercie region, southern Poland)

    Energy Technology Data Exchange (ETDEWEB)

    Samborska, Katarzyna, E-mail: samborska@ietu.katowice.pl [Institute for Ecology of Industrial Areas, 6 Kossutha St., 40-844 Katowice (Poland); Halas, Stanislaw [Mass Spectrometry Laboratory, Marie Curie-Sklodowska University, 20-031 Lublin (Poland)

    2010-09-15

    Research highlights: {yields} Groundwater table rebound in aquifer containing sulfide ore. {yields} Degradation of water quality causes by the significant increase in sulfate concentrations. {yields} Isotopic examinations of sulfate and sulfate concentrations along flow path. {yields} Sulfate concentrations as a result of binary mixing of sources (sulfide and evaporate). {yields} Changes in isotopic composition of sulfide in extended vadose zone. - Abstract: The objective of this study was to determine the sources of SO{sub 4}{sup 2-} in groundwater of the Olkusz-Zawiercie Major Groundwater Body. The quality of groundwater was relatively good in the past, but fluctuations of the water table level have caused degradation of water quality. Variations in the water table level and the formation of the depression cone have resulted from both groundwater withdrawal and Zn-Pb mine dewatering. As a result within the extended vadose zone of the aquifer, weathering of pyrite and accompanying sulfides has taken place. Since 1992 the water table has risen and this process has been associated with an increase in concentrations of SO{sub 4}{sup 2-}, Ca and Mg. At the same time, the pH has decreased and periodically high Fe concentrations have been detected. High concentrations of Mg and Sr have been observed and, since gypsum layers are known to be present, a de-dolomitisation process has been hypothesized. The PHREEQC program for Windows was used to estimate saturation indices for calcite, dolomite, gypsum and epsomite. Isotopic data for SO{sub 4}{sup 2-} dissolved in the groundwater and archival data on isotopic composition of ore sulfides were used to solve the isotope balance equation and to estimate the fraction of dissolved SO{sub 4}{sup 2-} that originated from pyrite oxidation and gypsum dissolution. The results have shown that dissolution of pyrite oxidation products has a significant influence on chemical composition of groundwater, especially in the southern part of

  15. Colloid formation in groundwater: effect of phosphate, manganese, silicate and dissolved organic matter on the dynamic heterogeneous oxidation of ferrous iron

    NARCIS (Netherlands)

    Wolthoorn, A.; Temminghoff, E.J.M.; Weng, L.P.; Riemsdijk, van W.H.

    2004-01-01

    Subsurface aeration is the in situ oxidation of Fe from groundwater that is used to make drinking water potable. When subsurface aeration is applied to an anaerobic groundwater system with pH > 7, Fe(II) is oxidised heterogeneously. The heterogeneous oxidation of Fe(II) can result in the in situ

  16. Impact of water table depth and shallow groundwater use on salt leaching cycle in irrigated areas%灌区地下水控制埋深与利用量对洗盐周期的影响

    Institute of Scientific and Technical Information of China (English)

    李山; 罗纨; 贾忠华; 潘延鑫; 武迪

    2014-01-01

    groundwater salinity maintained at 4.43 g/L;when the water table depth is greater than 2 m, the calculated leaching cycle is longer than the growing period. In another case study in an arid irrigation area with saline groundwater buried at 1.5 m deep, the calculated leaching cycle for plastic mulched and drip irrigated cotton is 78 days, applying slightly saline irrigation water with salinity of 2.81 g/L. These results indicate that managing water table depth under con-trolled drainage practice may increase crop use of shallow groundwater that contains dissolved salts, the rate of salinity buildup, however, is relatively slow, leaving a time window for making proper leaching schedule. The results from this study provide theoretical reference for salinity management in irrigated agri-cultural regions that adopt controlled drainage technique.

  17. Sustainable Irrigation with Brackish Groundwater in Heilonggang Region, China

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Saline groundwater is widely distributed in Heilonggang region. While deep confined water is being mined, saline water has not been used in most part of the region. Extension of saline water irrigation is of significance to resolve water shortage, slow down environmental degradation and support the sustainable development of the local agriculture. Four key points are proposed to be managed by comprehensive measures: (1) adapting salt-resistant ability; (2) reducing salt input; (3) decreasing soil surface evaporation and salt accumulation in the root zone, and (4) washing away salt from the root zone. Experiments and farming practices demonstrated that brackish water with TDS (total dissolved solids) of 2-5 g/l can be used for crop irrigation. For example, winter wheat can be sustainably irrigated by brackish water with a water limitation of 120 mm every year. Irrigation in combination with different comprehensive measures can increase the efficiency of saline water irrigation.

  18. Ultraviolet-Visible and Fluorescence Analyses Reveal the Spatial and Seasonal Variability of Dissolved Organic Matter through the Vadose Zone to Groundwater at the Rifle, Colorado River Floodplain Site

    Science.gov (United States)

    Dong, W.; Wan, J.; Tokunaga, T. K.; Gilbert, B.; Kim, Y.; Williams, K. H.

    2014-12-01

    Dissolved organic matter (DOM) is a complex and poorly understood mixture of natural organic compounds that play important roles in terrestrial C transport and biogeochemical cycles, and its reactivity makes it sensitive to seasonal variations and longer term climate change. As a component within the LBNL Science Focus Area 2.0, this study is designed to determine the spatial and temporal variability of DOM concentrations and characteristics throughout the vadose zone and groundwater within a semi-arid floodplain at Rifle, Colorado. Three sets of vertically stratified pore water samplers and wells were installed along a groundwater flow transect. These installations allowed acquisition of vertically- and temporally-resolved pore water samples from the vadose zone, capillary fringe, and saturated zone from April 2013 to May 2014. Ultraviolet-visible absorbance (UVA) and fluorescence excitation-emission matrix (EEM) spectroscopy are being applied to trace the changes in DOM characteristics. Initial results indicate that the aromatic C contents (%) of DOM vary with depth and season and exhibit patterns distinct from groundwater. EEM analysis identified fulvic- and humic-like substances as the major fluorescent components of DOM in pore water samples. The concentrations of fulvic- and humic-like matter decreases with depth within the vadose zone, and increases from Spring and Summer to Fall, then decreases in Winter. The trend is consistent with UVA results. Microbial by-product-like components in DOM show higher concentrations in the vadose zone, and decrease from Spring to Winter. Fulvic- and humic-like substances are the only detectable fluorophore components in the groundwater samples. The results from both UVA and EEM suggest that (1) aromatic C or fulvic- and humic-like matter are preferentially adsorbed within shallower sediments during transport; and (2) microbial transformations of DOM composition may occur in the vadose zone, particularly during late Spring

  19. Seasonal changes in submarine groundwater discharge to coastal salt ponds estimated using 226Ra and 228Ra as tracers

    Science.gov (United States)

    Hougham, A.L.; Moran, S.B.; Masterson, J.P.; Kelly, R.P.

    2008-01-01

    Submarine groundwater discharge (SGD) to coastal southern Rhode Island was estimated from measurements of the naturally-occurring radioisotopes 226Ra (t1/2 = 1600??y) and 228Ra (t1/2 = 5.75??y). Surface water and porewater samples were collected quarterly in Winnapaug, Quonochontaug, Ninigret, Green Hill, and Pt. Judith-Potter Ponds, as well as nearly monthly in the surface water of Rhode Island Sound, from January 2002 to August 2003; additional porewater samples were collected in August 2005. Surface water activities ranged from 12-83??dpm 100??L- 1 (60??dpm = 1??Bq) and 21-256??dpm 100??L- 1 for 226Ra and 228Ra, respectively. Porewater 226Ra activities ranged from 16-736??dpm 100??L- 1 (2002-2003) and 95-815??dpm 100??L- 1 (2005), while porewater 228Ra activities ranged from 23-1265??dpm 100??L- 1. Combining these data with a simple box model provided average 226Ra-based submarine groundwater fluxes ranging from 11-159??L m- 2 d- 1 and average 228Ra-derived fluxes of 15-259??L m- 2 d- 1. Seasonal changes in Ra-derived SGD were apparent in all ponds as well as between ponds, with SGD values of 30-472??L m- 2 d- 1 (Winnapaug Pond), 6-20??L m- 2 d- 1 (Quonochontaug Pond), 36-273??L m- 2 d- 1 (Ninigret Pond), 29-76??L m- 2 d- 1 (Green Hill Pond), and 19-83??L m- 2 d- 1 (Pt. Judith-Potter Pond). These Ra-derived fluxes are up to two orders of magnitude higher than results predicted by a numerical model of groundwater flow, estimates of aquifer recharge for the study period, and values published in previous Ra-based SGD studies in Rhode Island. This disparity may result from differences in the type of flow (recirculated seawater versus fresh groundwater) determined using each technique, as well as variability in porewater Ra activity. ?? 2007 Elsevier B.V. All rights reserved.

  20. Prediction of activity coefficients in liquid aerosol particles containing organic compounds, dissolved inorganic salts, and water—Part 1: Organic compounds and water by consideration of short- and long-range effects using X-UNIFAC.1

    Science.gov (United States)

    Erdakos, Garnet B.; Asher, William E.; Seinfeld, John H.; Pankow, James F.

    The semi-empirical group contribution method (GCM) of Kikic et al. [Chem. Eng. Sci. 46 (1991) 2775-2780] for estimating activity coefficient ( ζ) values of neutral organic compounds and water in solutions composed of organic compounds, dissolved inorganic salts, and water is adapted for application to atmospheric particulate matter (PM). It is assumed that ζ values are determined by a combination of short- and long-range interactions. The ζ expression involves conventional UNIFAC terms and a Debye-Hückel term, with the former computed using group-group interaction parameters. Organic-organic interaction parameters are assigned the values from the UNIFAC-LLE model of Magnussen et al. [Ind. Eng. Chem. Process Design Develop. 20 (1981) 331-339]. Forty interaction parameters (ion-solvent group and anion-cation) were obtained from Kikic et al. [Chem. Eng. Sci. 46 (1991) 2775-2780], Achard et al. [Fluid Phase Equilibria 98 (1994) 71-89], and Ming and Russell [Am. Inst. Chem. Eng. J. 48 (2002) 1331-1348]. Twenty additional interaction parameters (ion-solvent group) are estimated based on 879 UNIQUAC-fitted ζ values for organic compounds and water. The fitted ζ values are based on liquid-liquid equilibrium (LLE) data for a range of ternary and quaternary organic/inorganic salt/water mixtures at 293-308 K. The UNIQUAC fits are analogous to those described by Fredenslund et al. [Vapor-Liquid Equilibria Using UNIFAC: A Group-Contribution Method, Elsevier Scientific Publishing, New York, 1977]. The LLE mixture compositions range from primarily organic solutions to primarily aqueous solutions with maximum ionic strengths of ˜5 mol kg -1. The groups characteristic of organic compounds found in atmospheric PM considered here include: CH 3-, -CH 2-, -CH|-, -C||-, -OH, -CH 2CO-, and -COOH. These are: single bonded carbon with three, two, one, and zero hydrogens, respectively, hydroxyl, -CH 2-carbonyl, and carboxyl, respectively. The inorganic salts represented in the mixture

  1. Trends in concentrations of nitrate and total dissolved solids in public supply wells of the Bunker Hill, Lytle, Rialto, and Colton groundwater subbasins, San Bernardino County, California: Influence of legacy land use

    Science.gov (United States)

    Kent, Robert; Landon, Matthew K.

    2013-01-01

    Concentrations and temporal changes in concentrations of nitrate and total dissolved solids (TDS) in groundwater of the Bunker Hill, Lytle, Rialto, and Colton groundwater subbasins of the Upper Santa Ana Valley Groundwater Basin were evaluated to identify trends and factors that may be affecting trends. One hundred, thirty-one public-supply wells were selected for analysis based on the availability of data spanning at least 11 years between the late 1980s and the 2000s. Forty-one of the 131 wells (31%) had a significant (p < 0.10) increase in nitrate and 14 wells (11%) had a significant decrease in nitrate. For TDS, 46 wells (35%) had a significant increase and 8 wells (6%) had a significant decrease. Slopes for the observed significant trends ranged from − 0.44 to 0.91 mg/L/yr for nitrate (as N) and − 8 to 13 mg/L/yr for TDS. Increasing nitrate trends were associated with greater well depth, higher percentage of agricultural land use, and being closer to the distal end of the flow system. Decreasing nitrate trends were associated with the occurrence of volatile organic compounds (VOCs); VOC occurrence decreases with increasing depth. The relations of nitrate trends to depth, lateral position, and VOCs imply that increasing nitrate concentrations are associated with nitrate loading from historical agricultural land use and that more recent urban land use is generally associated with lower nitrate concentrations and greater VOC occurrence. Increasing TDS trends were associated with relatively greater current nitrate concentrations and relatively greater amounts of urban land. Decreasing TDS trends were associated with relatively greater amounts of natural land use. Trends in TDS concentrations were not related to depth, lateral position, or VOC occurrence, reflecting more complex factors affecting TDS than nitrate in the study area.

  2. Trends in concentrations of nitrate and total dissolved solids in public supply wells of the Bunker Hill, Lytle, Rialto, and Colton groundwater subbasins, San Bernardino County, California: influence of legacy land use.

    Science.gov (United States)

    Kent, Robert; Landon, Matthew K

    2013-05-01

    Concentrations and temporal changes in concentrations of nitrate and total dissolved solids (TDS) in groundwater of the Bunker Hill, Lytle, Rialto, and Colton groundwater subbasins of the Upper Santa Ana Valley Groundwater Basin were evaluated to identify trends and factors that may be affecting trends. One hundred, thirty-one public-supply wells were selected for analysis based on the availability of data spanning at least 11 years between the late 1980s and the 2000s. Forty-one of the 131 wells (31%) had a significant (pwells (11%) had a significant decrease in nitrate. For TDS, 46 wells (35%) had a significant increase and 8 wells (6%) had a significant decrease. Slopes for the observed significant trends ranged from -0.44 to 0.91 mg/L/yr for nitrate (as N) and -8 to 13 mg/L/yr for TDS. Increasing nitrate trends were associated with greater well depth, higher percentage of agricultural land use, and being closer to the distal end of the flow system. Decreasing nitrate trends were associated with the occurrence of volatile organic compounds (VOCs); VOC occurrence decreases with increasing depth. The relations of nitrate trends to depth, lateral position, and VOCs imply that increasing nitrate concentrations are associated with nitrate loading from historical agricultural land use and that more recent urban land use is generally associated with lower nitrate concentrations and greater VOC occurrence. Increasing TDS trends were associated with relatively greater current nitrate concentrations and relatively greater amounts of urban land. Decreasing TDS trends were associated with relatively greater amounts of natural land use. Trends in TDS concentrations were not related to depth, lateral position, or VOC occurrence, reflecting more complex factors affecting TDS than nitrate in the study area.

  3. 不同潜水埋深下土壤水盐运移特征及其交互效应%Migration characteristics of soil water and salt and their interaction under different groundwater levels

    Institute of Scientific and Technical Information of China (English)

    夏江宝; 赵西梅; 赵自国; 陈印平; 刘俊华

    2015-01-01

    为探讨盐水矿化度下土壤水盐分布特征对潜水埋深的响应规律及其水盐交互效应,以黄河三角洲建群种柽柳(Tamarix chinensis Lour)栽植的土壤柱体为研究对象,模拟设置0.3、0.6、0.9、1.2、1.5和1.8 m共6种潜水水位,测定分析各水位处理下不同土壤剖面的相对含水率、含盐量及土壤溶液绝对浓度等水盐参数。结果表明:随潜水水位的增加,整个土柱水分均值显著降低,土壤含盐量和溶液绝对浓度均值先升高后降低,1.2 m水位是土壤水盐变化的转折点,此水位下各土壤剖面的含盐量和土壤溶液绝对浓度均达最高。土柱水分和盐分变化幅度最大的水位分别在中水位0.9~1.2 m,浅水位0.6 m,土壤溶液绝对浓度变化最剧烈的是深水位1.5~1.8 m。随土壤深度的增加,土壤水分显著升高,土壤盐分先降低后升高,表土层盐分均值最高达1.36%,但土壤溶液绝对浓度显著减小。土壤含盐量、土壤相对含水率与潜水水位分别呈极显著(P<0.01)和显著(P<0.05)负相关,土壤相对含水率与盐分呈极显著正相关(P<0.01)。地下盐水矿化度下,柽柳幼苗栽植深度应超过20 cm深,适宜潜水水位在1.5~1.8 m,栽植深度以30~40 cm较好。研究结果可为地下盐水作用条件下土壤次生盐渍化的防治和柽柳栽植管理提供参考。%Soil salt and water closely related to groundwater depth mainly affect vegetation distribution pattern and community succession of the Yellow River Delta. Thus,it is important to explain the changing process of water and salt in groundwater and soil and their effects on the occurrence of the secondary salinization. This study aimed to understand the response of soil water-salt distribution characteristics to groundwater depth and their interactive effects under saline groundwater conditions. To achieve the objective, a laboratory experiment was

  4. Dissolved oxygen

    National Research Council Canada - National Science Library

    1981-01-01

    Dissolved oxygen concentrations in the waters of Botany Bay and Georges and Cooks Rivers vary mainly as a result of tidal water movements, algal and macrophytic growth and decay, and effects of storms...

  5. Simulated flow of groundwater and brine from a flooded salt mine in Livingston County, New York, and effects of remedial pumping on an overlying aquifer

    Science.gov (United States)

    Yager, Richard M.; Miller, Todd S.; Kappel, William M.; Misut, Paul E.; Langevin, Christian D.; Parkhurst, David L.; deVries, M. Peter

    2012-01-01

    Two ceiling collapses in the Retsof salt mine near Geneseo in upstate New York in spring 1994 resulted in the upward propagation of two columns of rubble through 600 feet of overlying shale and carbonate bedrock. This upward propagation formed a hydraulic connection between the lower confined aquifer (LCA) and the mine and allowed water from the aquifer and bedrock fracture zones that intersected the rubble columns to flow into the mine at a rate of 18,000 gallons per minute (gal/min) . All salt mining ceased in September 1995, and the mine was completely flooded by January 1996. The flow of water from the lower confined aquifer into the mine caused widespread drawdowns, and water levels in the aquifer declined by as much as 400 feet near the collapse area and by more than 50 feet at wells 7 miles to the north and south. Within 3 to 4 weeks of the collapses, water levels in about a dozen domestic and industrial wells had declined severely, and some wells went dry. Water levels in at least 58 wells in the lower and middle confined aquifers were affected by mine flooding. Groundwater in the upper unconfined aquifer and surface water in streams were unaffected by water-level drawdown, but channels of the Genesee River and Beards Creek were altered by land subsidence related to the mine collapse. Water levels recovered from 1996 through 2006, but the mine is now filled with about 15 billion gallons of saturated halite brine. The weight of the overlying rock and sediment is expected to cause the salt beds to deform and fill the mine cavity during the next several hundred years; this in turn could displace as much as 80 percent of the brine and cause it to move upward through the rubble chimneys, rendering the LCA unusable as a source of water supply. Saline water was detected in the LCA in 2002 but was found to be derived primarily from fractures in the limestone and shale units between the mine and the LCA, rather than from the mine. In September 2006, the mine company

  6. Hydrology of the Poverty Bay flats aquifers, New Zealand: recharge mechanisms, evolution of the isotopic composition of dissolved inorganic carbon, and ground-water ages

    Science.gov (United States)

    Taylor, C. B.

    1994-06-01

    With the exception of water-bearing remnants of earlier fluvial gravels overlying basement, the sediments of the Poverty Bay flats have accumulated during the postglacial period of the past 14 000 years, and have been tilted and deformed by recent tectonism. A sequence of gravel aquifers, separated by poorly permeable silt layers, lies between surface and basement, which is at depths varying between 50 and 200 m. A shallow sand/silt aquifer is situated near the coast. This study applies evidence of chemical and isotopic properties of river and ground water to clarify the recharge mechanisms, chemical evolution and age of the ground water in the aquifers. Particular attention is paid to the evolution of dissolved inorganic carbon content, applying carbon-14 data measured by accelerator mass spectrometry. Most of the ground water is recharged from the Waipaoa River, which flows across the flats and discharges into Poverty Bay. The two deepest aquifers (Matokitoki and Makauri) are both tritium-free; the deeper Matokitoki Gravels yield water of age about 4300 years since recharge (possibly up to 1300 years greater), but the Makauri water is no older than 100-200 years, discharging slowly through overlying aquitards near the limit of closest approach to the present coast.

  7. Methane bioattenuation and implications for explosion risk reduction along the groundwater to soil surface pathway above a plume of dissolved ethanol.

    Science.gov (United States)

    Ma, Jie; Rixey, William G; DeVaull, George E; Stafford, Brent P; Alvarez, Pedro J J

    2012-06-05

    Fuel ethanol releases can stimulate methanogenesis in impacted aquifers, which could pose an explosion risk if methane migrates into enclosed spaces where ignitable conditions exist. To assess this potential risk, a flux chamber was emplaced on a pilot-scale aquifer exposed to continuous release (21 months) of an ethanol solution (10% v:v) that was introduced 22.5 cm below the water table. Despite methane concentrations within the ethanol plume reaching saturated levels (20-23 mg/L), the maximum methane concentration reaching the chamber (21 ppm(v)) was far below the lower explosion limit in air (50,000 ppm(v)). The low concentrations of methane observed in the chamber are attributed to methanotrophic activity, which was highest in the capillary fringe. This was indicated by methane degradation assays in microcosms prepared with soil samples from different depths, as well as by PCR measurements of pmoA, which is a widely used functional gene biomarker for methanotrophs. Simulations with the analytical vapor intrusion model "Biovapor" corroborated the low explosion risk associated with ethanol fuel releases under more generic conditions. Model simulations also indicated that depending on site-specific conditions, methane oxidation in the unsaturated zone could deplete the available oxygen and hinder aerobic benzene biodegradation, thus increasing benzene vapor intrusion potential. Overall, this study shows the importance of methanotrophic activity near the water table to attenuate methane generated from dissolved ethanol plumes and reduce its potential to migrate and accumulate at the surface.

  8. Environmental consequences of the Retsof Salt Mine roof collapse

    Science.gov (United States)

    Yager, Richard M.

    2013-01-01

    In 1994, the largest salt mine in North America, which had been in operation for more than 100 years, catastrophically flooded when the mine ceiling collapsed. In addition to causing the loss of the mine and the mineral resources it provided, this event formed sinkholes, caused widespread subsidence to land, caused structures to crack and subside, and changed stream flow and erosion patterns. Subsequent flooding of the mine drained overlying aquifers, changed the groundwater salinity distribution (rendering domestic wells unusable), and allowed locally present natural gas to enter dwellings through water wells. Investigations including exploratory drilling, hydrologic and water-quality monitoring, geologic and geophysical studies, and numerical simulation of groundwater flow, salinity, and subsidence have been effective tools in understanding the environmental consequences of the mine collapse and informing decisions about management of those consequences for the future. Salt mines are generally dry, but are susceptible to leaks and can become flooded if groundwater from overlying aquifers or surface water finds a way downward into the mined cavity through hundreds of feet of rock. With its potential to flood the entire mine cavity, groundwater is a constant source of concern for mine operators. The problem is compounded by the viscous nature of salt and the fact that salt mines commonly lie beneath water-bearing aquifers. Salt (for example halite or potash) deforms and “creeps” into the mined openings over time spans that range from years to centuries. This movement of salt can destabilize the overlying rock layers and lead to their eventual sagging and collapse, creating permeable pathways for leakage of water and depressions or openings at land surface, such as sinkholes. Salt is also highly soluble in water; therefore, whenever water begins to flow into a salt mine, the channels through which it flows increase in diameter as the surrounding salt dissolves

  9. Changes between early development (1930–60) and recent (2005–15) groundwater-level altitudes and dissolved-solids and nitrate concentrations In and near Gaines, Terry, and Yoakum Counties, Texas

    Science.gov (United States)

    Thomas, Jonathan V.; Teeple, Andrew; Payne, Jason; Ikard, Scott

    2016-06-21

    Llano Estacado Underground Water Conservation District, Sandy Land Underground Water Conservation District, and South Plains Underground Water Conservation District manage groundwater resources in a part of west Texas near the Texas-New Mexico State line. Declining groundwater levels have raised concerns about the amount of available groundwater in the study area and the potential for water-quality changes resulting from dewatering and increased vertical groundwater movement between adjacent water-bearing units.

  10. Hydrogeochemical studies of groundwater in Salem District, Tamil Nadu (India).

    Science.gov (United States)

    Maheswaran, G; Elangovan, K

    2010-01-01

    Salem is one of the industrial, agricultural and mineral deposit based district in Tamil Nadu. In this paper, an attempt is made to assess the quality of groundwater in this district, during the month of May 2007 (pre-monsoon). The government of Tamil Nadu has divided the district into twenty blocks. Sixty six samples were collected covering all the blocks of the district except Yercaud which is a structural hill. The collected samples were tested for the following parameters: electrical conductivity, turbidity, pH, total hardness, iron, chlorides, total dissolved solids, calcium, magnesium, potassium, manganese, sulphate, nitrate, nitrite and total alkalinity. The test results were interpreted using IS 10500-1991, statistical methods, SAR, USSL classification and Piper's trilinear diagram. Based on the interpretation it is concluded that the study area is mostly influenced by the presence of electrical conductivity, total dissolved solids, total hardness, chloride and total alkalinity whereas the other minerals and salts play a minor role.

  11. Hydrochemical and multivariate analysis of groundwater quality in the northwest of Sinai, Egypt.

    Science.gov (United States)

    El-Shahat, M F; Sadek, M A; Salem, W M; Embaby, A A; Mohamed, F A

    2017-08-01

    The northwestern coast of Sinai is home to many economic activities and development programs, thus evaluation of the potentiality and vulnerability of water resources is important. The present work has been conducted on the groundwater resources of this area for describing the major features of groundwater quality and the principal factors that control salinity evolution. The major ionic content of 39 groundwater samples collected from the Quaternary aquifer shows high coefficients of variation reflecting asymmetry of aquifer recharge. The groundwater samples have been classified into four clusters (using hierarchical cluster analysis), these match the variety of total dissolvable solids, water types and ionic orders. The principal component analysis combined the ionic parameters of the studied groundwater samples into two principal components. The first represents about 56% of the whole sample variance reflecting a salinization due to evaporation, leaching, dissolution of marine salts and/or seawater intrusion. The second represents about 15.8% reflecting dilution with rain water and the El-Salam Canal. Most groundwater samples were not suitable for human consumption and about 41% are suitable for irrigation. However, all groundwater samples are suitable for cattle, about 69% and 15% are suitable for horses and poultry, respectively.

  12. The Slow Moving Threat of Groundwater Salinization: Mechanisms, Costs, and Adaptation Strategies

    Science.gov (United States)

    Pauloo, R.; Guo, Z.; Fogg, G. E.

    2016-12-01

    Population growth, the Green Revolution, and climate uncertainties have accelerated overdraft in groundwater basins worldwide, which in some regions is converting these basins into closed hydrologic systems, where the dominant exits for water are evapotranspiration and pumping. Irrigated agricultural basins are particularly at risk to groundwater salinization, as naturally occurring (i.e., sodium, potassium, chloride) and anthropogenic (i.e., nitrate fertilizers) salts leach back into the water table through the root zone, while a large portion of pumped groundwater leaves the system as it is evapotranspired by crops. Decreasing water quality associated with increases in Total Dissolved Solids (TDS) has been documented in aquifers across the United States in the past half century. This study suggests that the increase in TDS in aquifers can be partially explained by closed basin hydrogeology and rock-water interactions leading to groundwater salinization. This study will present: (1) a report on historical water quality in the Tulare basin, (2) a forward simulation of salt balance in Tulare Basin based on the Department of Water Resources numerical model C2VSim, and a simple mixing model, (3) an economic analysis forecasting the cost of desalination under varying degrees of managed groundwater recharge where the basin is gradually filled, avoiding hydraulic closure.

  13. Natural versus human control on subsurface salt dissolution and development of thousands of sinkholes along the Dead Sea coast

    Science.gov (United States)

    Abelson, Meir; Yechieli, Yoseph; Baer, Gidon; Lapid, Gil; Behar, Nicole; Calvo, Ran; Rosensaft, Marcelo

    2017-06-01

    One of the most hazardous results of the human-induced Dead Sea (DS) shrinkage is the formation of more than 6000 sinkholes over the last 25 years. The DS shrinkage caused eastward retreat of underground brine replaced by fresh groundwater, which in turn dissolved a subsurface salt layer, to generate cavities and collapse sinkholes. The areal growth rate of sinkhole clusters is considered the most pertinent proxy for sinkholes development. Analysis of light detection and ranging, digital elevation models, and interferometric synthetic aperture radar allows translation of the areal growth rate to a salt dissolution rate of the salt layer, revealing two peaks in the history of the salt dissolution rate. These peaks cannot be attributed to the decline of the DS level. Instead, we show that they are related to long-term variations of precipitation in the groundwater source region, the Judea Mountains, and the delayed response of the aquifer system between the mountains and the DS rift. This response is documented by groundwater levels and salinity variations. We thus conclude that while the DS level decline is the major trigger for sinkholes formation, the rainfall variations more than 30 km to the west dominate their evolution rate. The influence of increasing rainfall in the Judea Mountains reaches the DS at a typical time lag of 4 years, and the resulting increase in the salt dissolution rate lags by a total time of 5-6 years.

  14. The influence of marine inflows on the chemical composition of groundwater in small islands: the example of the Cyclades (Greece)

    Energy Technology Data Exchange (ETDEWEB)

    Dazy, J. [Laboratoire d`Hydrogeologie, Universite des Sciences et Techniques, 34 - Montpellier (France); Drogue, C. [Laboratoire d`Hydrogeologie, Universite des Sciences et Techniques, 34 - Montpellier (France); Charmanidis, P. [Institute of Geology and Mining Exploration (I.G.M.E.), Athens (Greece); Darlet, C. [Laboratoire d`Hydrogeologie, Universite des Sciences et Techniques, 34 - Montpellier (France)

    1997-06-01

    Marine contamination of groundwater may be caused by seawater intrusion and by salt spray. The role of both processes was studied in the Cyclades archipelago on four small islands (45-195 km{sup 2}) whose aquifers consist essentially of fractured, weathered metamorphic rocks. Annual rainfall ranges from 400 to 640 mm and precipitation has high total dissolved solids contents of 45-223 mg l{sup -1}. The chemical characteristics of the groundwater, whose salinity is from 0.4 to 22 g l{sup -1}, are strongly influenced by seawater intrusion. However, the effect of atmospheric input is shown in certain water sampling locations on high ground elevation where the dissolved chloride contents may attain 200 mg l{sup -1}. (orig.)

  15. Modeling soil water-salt dynamics and maize yield responses to groundwater depths and irrigations%土壤水盐与玉米产量对地下水埋深及灌溉响应模拟

    Institute of Scientific and Technical Information of China (English)

    郝远远; 徐旭; 黄权中; 黄冠华

    2014-01-01

    引黄水量的削减将进一步加剧宁夏银北灌区农业用水短缺问题,合理应用地下水进行灌溉对保障作物产量具有重要意义。为探究地下水灌溉条件下土壤水盐与作物生长的互馈机制,该研究修正了HYDRUS-1D的土壤蒸发模块,并嵌入可模拟作物生长与产量的 EPIC 模块,以此提高该模型在农田水文过程模拟中的适用性。采用2008年银北灌区不同水质灌水处理的玉米田间试验数据对模型进行了率定与验证。进一步应用该模型探寻地下水灌溉条件下,土壤水盐动态及玉米产量对地下水埋深变动及灌溉的响应规律。结果表明,玉米产量随地下水埋深增大呈现先增后减趋势,为保障玉米产量应将地下水适宜埋深控制在140~155 cm,且灌水量不宜低于现状灌水量,即玉米生育期内灌3水,每次900 m3/hm2。该研究对干旱银北灌区农业生产具有重要意义。%Reduction of water diversion from the Yellow River will intensify water shortage problems in the Yinbei Irrigation District (YID). Reasonable use of groundwater for irrigation is helpful to maintain the agricultural production. Groundwater exploitation may cause groundwater level declines in local areas. This helps to reduce the salinity accumulation in the root zone but decreases the capillary rise. Thus, it is important to figure out the responses of soil water-salt dynamics and crop yields to groundwater table fluctuations for salinity control and stable yields. In this study, HYDRUS-1D model was modified by coupling with the EPIC (erosion-productivity impact calculator) crop growth module for simulating agro-hydrological processes. The new crop module could simulate crop height, leaf area index (LAI), above-ground biomass and crop yield. The information between HYDRUS-1D and EPIC was exchanged by daily step. Root water uptake under water and salt stress was calculated with HYDRUS-1D and imported to EPIC to

  16. Hydrochemical assessment of groundwater used for irrigation in Rumphi and Karonga districts, Northern Malawi

    Science.gov (United States)

    Wanda, Elijah M. M.; Gulula, Lewis C.; Phiri, Ambrose

    Irrigation water quality is an essential component of sustainable agriculture. Irrigation water quality concerns have often been neglected over concerns of quantity in most irrigation projects in Malawi. In this study, a hydrochemical assessment of groundwater was carried out to characterize, classify groundwater and evaluate its suitability for irrigation use in Karonga and Rumphi districts, Northern Malawi. Groundwater samples were collected during wet (January-April 2011) and dry (July-September 2011) seasons from 107 shallow wells and boreholes drilled for rural water supply using standard sampling procedures. The water samples were analysed for pH, major ions, total dissolved solids and electrical conductivity (EC), using standard methods. Multivariate chemometric (such as Kruskal Wallis test), hydrographical methods (i.e. Piper diagram) and PHREEQC geochemical modelling program were used to characterise the groundwater quality. Electrical conductivity, percentage sodium ion (% Na+), residual sodium carbonate (RSC), total dissolved solids (TDS), sodium adsorption ratio (SAR), Kelly’s ratio (KR) and permeability index (PI) were used to evaluate the suitability of water for irrigation. It was established that groundwater is neutral to alkaline and mostly freshwater (TDS RSC (6% from Karonga district), unsuitable PI (5% and 3% from Karonga and Rumphi, respectively) and a high salinity hazard (56.2% and 20.3% from Karonga and Rumphi, respectively) values restrict the suitability of the groundwater for agricultural purposes, and plants with good salt tolerance should be selected for such groundwaters. A detailed hydro-geochemical investigation and integrated water management is suggested for sustainable development of the water resources for better plant growth, long-term as well as maintaining human health in the study area.

  17. Development of a Carbon Isotope-Based Tracer of Groundwater Fluxes into Estuaries and the Coastal Ocean.

    Science.gov (United States)

    McCorkle, D. C.; Gramling, C. M.; Mulligan, A. E.; Woods, T. L.

    2001-05-01

    We will show how the carbon isotopic composition of dissolved inorganic carbon (DIC) - in particular, its radiocarbon content (Δ 14C) - can be used to quantify the contribution of confined groundwater flow to the total land-sea freshwater flux. The key observation underlying this approach is that groundwater in confined aquifers typically has a much lower radiocarbon content than surface fresh water (rivers and streams, and the water table groundwater that feeds them). We illustrate this method using chemical and isotopic data from Pages Creek and Futch Creek, two small estuaries on the Intracoastal Waterway near Wilmington, NC. Isotopic analyses of groundwater in coastal NC, of springs in Pages Creek and Futch Creek, and of the known DIC sources to these tidal creeks (sea water, stream water, and CO2 from salt marsh decomposition processes), show that confined aquifers are the only significant low-Δ 14C DIC source to these estuaries. Salinity data constrain the total freshwater fraction (surface water + artesian groundwater) of each estuarine sample, and the radiocarbon data are then used to estimate the fractional groundwater contribution to the Pages Creek and Futch Creek freshwater budgets. We will also present preliminary carbon isotopic results from a unique set of salty "groundwater" samples from shallow seafloor wells from the South Carolina continental shelf. These data suggest that sub-bottom recirculation of seawater may impart a low-Δ 14C signal to shelf waters in this region.

  18. Dynamical variations in groundwater chemistry influenced by intermittent water delivery at the lower reaches of the Tarim River

    Institute of Scientific and Technical Information of China (English)

    CHENYongjin; CHENYaning; LIUJiazhen; LIWeihong; IJun; XUChangchun

    2005-01-01

    The water of Bosten Lake was released to lower reaches of the Tarim River for 5 times from 2000 to 2002. The changes of total dissolved solid (TDS) and the major ions (SO42-, Cl-, Na-,Ca2+, Mg2- and HCO3- ) were analyzed during this period. It was found out that TDS and the concentrations of the major ions initially and quickly increased and then decreased, but finally increased again. These changes were different at different distances from the river, which indicated that the groundwater changes relied on the distance from the river. In addition, the salt in groundwater was only diluted but not removed by the water. It was suggested that ecological measures should be sought to really promote the quality of the groundwater at the lower reaches of the Tarim River.

  19. Quantity and quality of groundwater discharge in a hypersaline lake environment

    Science.gov (United States)

    Anderson, R.B.; Naftz, D.L.; Day-Lewis, F. D.; Henderson, R.D.; Rosenberry, D.O.; Stolp, B.J.; Jewell, P.

    2014-01-01

    Geophysical and geochemical surveys were conducted to understand groundwater discharge to Great Salt Lake (GSL) and assess the potential significance of groundwater discharge as a source of selenium (Se). Continuous resistivity profiling (CRP) focusing below the sediment/water interface and fiber-optic distributed temperature sensing (FO-DTS) surveys were conducted along the south shore of GSL. FO-DTS surveys identified persistent cold-water temperature anomalies at 10 separate locations. Seepage measurements were conducted at 17 sites (mean seepage rate = 0.8 cm/day). High resistivity anomalies identified by the CRP survey were likely a mirabilite (Na2SO4·10H2O) salt layer acting as a semi-confining layer for the shallow groundwater below the south shore of the lake. Positive seepage rates measured along the near-shore areas of GSL indicate that a ∼1-m thick oolitic sand overlying the mirabilite layer is likely acting as a shallow, unconfined aquifer. Using the average seepage rate of 0.8 cm/day over an area of 1.6 km2, an annual Se mass loading to GSL of 23.5 kg was estimated. Determination of R/Ra values (calculated 3He/4He ratio over the present-day atmospheric 3He/4He ratio) 34S and δ18O isotopic values in samples of dissolved sulfate from the shallow groundwater below the mirabilite are almost identical to the isotopic signature of the mirabilite core material. The saturation index calculated for groundwater samples using PHREEQC indicates the water is at equilibrium with mirabilite. Water samples collected from GSL immediately off shore contained Se concentrations that were 3–4 times higher than other sampling sites >25 km offshore from the study site and may be originating from less saline groundwater seeps mixing with the more saline water from GSL. Additional evidence for mixing with near shore seeps is found in the δD and δ18O isotopic values and Br:Cl ratios. Geochemical modeling for a water sample collected in the vicinity of the study area

  20. Water quality and geochemistry evaluation of groundwater upstream and downstream of the Khirbet Al-Samra wastewater treatment plant/Jordan

    Science.gov (United States)

    Bajjali, William; Al-Hadidi, Kheir; Ismail, Ma'mmon

    2017-03-01

    Groundwater in the northeastern Amman-Zarqa basin is an important source of water for irrigation. The quality and quantity of water has deteriorated due to mismanagement and misunderstanding of the hydrogeological system. Overexploitation of groundwater resources upstream of the Khirbet Al-Samra wastewater treatment plant (KSWTP) has lowered the water table 43 m since the beginning of groundwater development in 1968. Heavy pumping of groundwater downstream of KSWTP has not dropped the water level due to constant recharge from the Zarqa river bed. The water level of groundwater is rising continuously at a rate of 20 cm per year since building the KSWTP in 1985. Groundwater salinity has also shifted the quality of the aquifer from fresh to brackish. Continual irrigation from the groundwater upstream of KSWTP dissolves accumulated salt from the soil formed by evaporation, and the contaminated water infiltrates back to the aquifer, thereby increasing both salt and nitrate concentrations. The intense irrigation from the reclaimed water downstream of KSWTP and leakage of treated wastewater from the Zarqa River to the shallow groundwater is a secondary source of salt and nitrates. The isotopic composition of groundwater varies over a wide range and is associated with the meteoric water line affected by Mediterranean Sea air moisture. The isotopic composition of groundwater is represented by evaporation line (EL) with a low slope of 3.6. The enrichment of groundwater in δ18O and δD is attributed mainly to the two processes of evaporation before infiltration of return flow and mixing of different types of water in KSWTP originating from different aquifers. The EL starts from a location more depleted than the weighted mean value of the Amman rainfall station on the Eastern Meteoric Water Line indicating that the recharge took place under the climate regime prevailing today in Jordan and the recharge of the groundwater originates from a greater elevation than that of the

  1. Characterization of groundwater in the Ejina Basin,northwest China:hydrochemical and environmental isotopes approaches

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    To characterize the groundwater in the Ejina Basin,surface and groundwater samples were collected in May and October of 2002.On-site analyses included temperature,electrical conductance(EC),total alkalinity(as HCO 3) by titration,and pH.Chemical analyses were undertaken at the Geochemistry Laboratory of the Cold and Arid Region Environmental and Engineering Institute,Chinese Academy of Sciences,Lanzhou,China.The pH of the groundwater ranged from 7.18 to 8.90 with an average value of 7.72,indicating an alkaline nature.The total dissolved solids(TDS) of the groundwater ranged from 567.5 to 5,954.4 mg/L with an average of 1,543.1 mg/L and a standard deviation of 1,471.8 mg/L.According to the groundwater salinity classification of Robinove et al.(1958),47.4 percent of the samples were brackish and the remainder were fresh water.The ion concentration of the groundwater along the riverbed and near the southern margin of the basin were lower than those farther away from the riverbed.The groundwater in the study area was of Na +-HCO 3 type near the bank of the Heihe River and in the southern margin of the basin,while Na +-SO 4 2-Cl type samples were observed in the terminal lake region.In the desert area the groundwater reached a TDS of 3,000-6,000 mg/L and was predominantly by a Na +-Cl chemistry.Br/Cl for the water of Ejina Basin indicates an evaporite origin for the groundwater with a strongly depleted Br/Cl ratio(average 0.000484).The surface water was slightly enriched in Br/Cl(average 0.000711) compared with groundwater.The calculated saturation index(SI) for calcite and dolomite of the groundwater samples range from 0.89 to 1.31 and 1.67 to 2.67 with averaged 0.24 and 0.61,respectively.About 97 percent of the groundwater samples were kinetically oversaturated with respect to calcite and dolomite,and all the samples were below the equilibrium state with gypsum.Using isotope and hydrochemical analyses,this study investigated the groundwater evolution and its residence

  2. Environmental isotopic and hydrochemical characteristics of groundwater from the Sandspruit Catchment, Berg River Basin, South Africa.

    Science.gov (United States)

    Naicker, S; Demlie, M

    2014-01-01

    The Sandspruit catchment (a tributary of the Berg River) represents a drainage system, whereby saline groundwater with total dissolved solids (TDS) up to 10,870 mg/l, and electrical conductivity (EC) up to 2,140 mS/m has been documented. The catchment belongs to the winter rainfall region with precipitation seldom exceeding 400 mm/yr, as such, groundwater recharge occurs predominantly from May to August. Recharge estimation using the catchment water-balance method, chloride mass balance method, and qualified guesses produced recharge rates between 8 and 70 mm/yr. To understand the origin, occurrence and dynamics of the saline groundwater, a coupled analysis of major ion hydrochemistry and environmental isotopes (δ(18)O, δ(2)H and (3)H) data supported by conventional hydrogeological information has been undertaken. These spatial and multi-temporal hydrochemical and environmental isotope data provided insight into the origin, mechanisms and spatial evolution of the groundwater salinity. These data also illustrate that the saline groundwater within the catchment can be attributed to the combined effects of evaporation, salt dissolution, and groundwater mixing. The salinity of the groundwater tends to vary seasonally and evolves in the direction of groundwater flow. The stable isotope signatures further indicate two possible mechanisms of recharge; namely, (1) a slow diffuse type modern recharge through a relatively low permeability material as explained by heavy isotope signal and (2) a relatively quick recharge prior to evaporation from a distant high altitude source as explained by the relatively depleted isotopic signal and sub-modern to old tritium values.

  3. Hydrogeochemistry of groundwater in parts of the Ayensu Basin of Ghana

    Directory of Open Access Journals (Sweden)

    Nafisatu Zakaria

    2012-06-01

    Full Text Available Twenty five groundwater samples were collected from parts of the Ayensu Basin in the Central Region of Ghana and were analysed for their physicochemical characteristics. The physicochemical parameters; pH, Conductivity, total dissolved solids (TDS, calcium (Ca 2+, magnesium (Mg 2+, sodium (Na +, potassium (K +, bicarbonate (HCO3 2-, chloride (Cl -, sulphate (SO4 2- and nitrate (NO3 - were analysed to know the present groundwater quality as well as the possible source of ions in the groundwater. The groundwater in the area is fresh and the dominant water types in the study area are Na-Cl and Na-HCO3-Cl: the occurrence of these facies is identified to be probably due to the dissolution of soluble salts in the soil horizon and aerosol spray. The occurrence of Na +, Cl -, K +, Ca 2+, Mg 2+ and SO4 2- in the groundwaters was also found to be probably caused by sea aerosol spray and decay of organic matter.

  4. Chemical Properties of Groundwater in Bhiloda Taluka Region, North Gujarat, India

    Directory of Open Access Journals (Sweden)

    G. D. Acharya

    2008-01-01

    Full Text Available Groundwater is one of the most useful water sources. Contamination of such water source is a big problem creating health hazards. In this present study we have collected groundwater samples from different places of Bhiloda taluka of Sabarkantha district (North Gujarat India. These samples have been assessed on the basis of various qualitative parameters. The results of physico-chemical study of water samples from 13 bore wells in Bhiloda taluka are presented. The water quality parameters such as; pH, electrical conductivity (EC, total dissolved salts (TDS, calcium and magnesium, sodium, potassium, carbonate, bicarbonate, chloride, sulphate, fluoride, sodium adsorption ratio (SAR, residual sodium carbonate (RSC and soluble sodium percentage ( SSP were estimated.

  5. Tehran Groundwater Chemical Pollution

    Directory of Open Access Journals (Sweden)

    M- Shariatpanahi

    1990-06-01

    Full Text Available Seventy eight wells water sample of Tehran plain were examined to determine r its groundwaters chemical pollution. Tehran s groundwaters are slightly acidic and their total dissolved solids are high and are in the hard water category."nThe nitrate concentration of wells water of west region is less than per¬missible level of W.H.O. standard, whereas, the nitrate concentration of some of the other regions wells exceed W.H.O. standard which is indication of pollution"nwith municipal wastewaters. The concentration of toxic elements Cr, Cd, As, Hg and"ni Pb of some of the west, east and south regions wells of Tehran is more than per¬missible level of W.H.O. standard, whereas, the concentration of Cu, Zn,Mn and detergents is below W.H.O. standard."n1"nIn general, the amount of dissolved materials of Tehran s groundwaters and also"ni the potential of their contamination with nitrate is increased as Tehran s ground-"nwaters move further to the south, and even though, Tehran s groundwaters contamination with toxic elements is limited to the industrial west district, industrial-residential east and south districts, but»with regard to the disposal methods of"nt municipal and industrial wastewaters, if Tehran s groundwaters pollution continues,"nlocal contamination of groundwaters is likely to spread. So that finally their quality changes in such a way that this water source may become unfit for most domestic, industrial and agricultural uses. This survey shows the necessity of collection and treatment of Tehran s wastewaters and Prevention of the disposal of untreated wastewaters into the environment.

  6. An Investigation of Quality of Groundwater of Taluka Nawabshah

    Directory of Open Access Journals (Sweden)

    . Khuhawar

    2011-06-01

    Full Text Available Sixty five water samples (four surface water and sixty one groundwater were collected from taluka Nawabshah and were analyzed for physico-chemical parameters; pH, electrical conductivity (EC, total dissolved salts (TDS and heavy metals, Fe, Zn, Cu, Mn, Co, Pb, Ni and Cd. The results were obtained in the ranges; pH 6.95-8.87, EC 239-13170 µS/cm and TDS 153-8429. The concentration of heavy metals was observed in the ranges; Fe 46-1070 µg/L, Zn 0-460 µg/L, Cu 3-311 µg/L, Mn 4-418 µg/L, Co 0-33 µg/L, Pb 6-50 µg/L, Ni 0-37µg/L and Cd 0-18µg/L. The results were compared with world health organization (WHO and local standards set for drinking water. Contamination index of groundwater was observed within 0.2-20.7. Only two water samples (both surface water were observed suitable for drinking purpose, but all the remaining samples were highly contaminated with toxic heavy metals. An elevated level of toxic heavy metals in the groundwater of the area is of great concern.

  7. Improving fresh groundwater supply - problems and solutions

    NARCIS (Netherlands)

    Oude Essink, Gualbert

    2001-01-01

    Many coastal regions in the world experience an intensive salt water intrusion in aquifers due to natural and anthropogenic causes. The salinisation of these groundwater systems can lead to a severe deterioration of the quality of existing fresh groundwater resources. In this paper, the

  8. Erosion patterns on dissolving blocks

    Science.gov (United States)

    Courrech du Pont, Sylvain; Cohen, Caroline; Derr, Julien; Berhanu, Michael

    2016-04-01

    Patterns in nature are shaped under water flows and wind action, and the understanding of their morphodynamics goes through the identification of the physical mechanisms at play. When a dissoluble body is exposed to a water flow, typical patterns with scallop-like shapes may appear [1,2]. These shapes are observed on the walls of underground rivers or icebergs. We experimentally study the erosion of dissolving bodies made of salt, caramel or ice into water solutions without external flow. The dissolving mixture, which is created at the solid/liquid interface, undergoes a buoyancy-driven instability comparable to a Rayleigh-Bénard instability so that the dissolving front destabilizes into filaments. This mechanism yields to spatial variations of solute concentration and to differential dissolution of the dissolving block. We first observe longitudinal stripes with a well defined wavelength, which evolve towards chevrons and scallops that interact and move again the dissolving current. Thanks to a careful analysis of the competing physical mechanisms, we propose scaling laws, which account for the characteristic lengths and times of the early regime in experiments. The long-term evolution of patterns is understood qualitatively. A close related mechanism has been proposed to explain structures observed on the basal boundary of ice cover on brakish lakes [3] and we suggest that our experiments are analogous and explain the scallop-like patterns on iceberg walls. [1] P. Meakin and B. Jamtveit, Geological pattern formation by growth and dissolution in aqueous systems, Proc. R. Soc. A 466, 659-694 (2010). [2] P.N. Blumberg and R.L. Curl, Experimental and theoretical studies of dissolution roughness, J. Fluid Mech. 65, 735-751 (1974). [3] L. Solari and G. Parker, Morphodynamic modelling of the basal boundary of ice cover on brakish lakes, J.G.R. 118, 1432-1442 (2013).

  9. Chemical characteristics of groundwater and assessment of groundwater quality in Varaha River Basin, Visakhapatnam District, Andhra Pradesh, India.

    Science.gov (United States)

    Rao, N Subba; Rao, P Surya; Reddy, G Venktram; Nagamani, M; Vidyasagar, G; Satyanarayana, N L V V

    2012-08-01

    Study on chemical characteristics of groundwater and impacts of groundwater quality on human health, plant growth, and industrial sector is essential to control and improve the water quality in every part of the country. The area of the Varaha River Basin is chosen for the present study, where the Precambrian Eastern Ghats underlain the Recent sediments. Groundwater quality is of mostly brackish and very hard, caused by the sources of geogenic, anthropogenic, and marine origin. The resulting groundwater is characterized by Na(+) > Mg(2+) > Ca(2+) : [Formula: see text] > Cl(-) > [Formula: see text], Na(+) > Mg(2+) > Ca(2+) : [Formula: see text] > Cl(-) > [Formula: see text] > [Formula: see text], Na(+) > Mg(2+) > Ca(2+) : [Formula: see text] > Cl(-), and Na(+) > Mg(2+) > Ca(2+) : Cl(-) > [Formula: see text] > [Formula: see text] facies, following the topographical and water flow-path conditions. The genetic geochemical evolution of groundwater ([Formula: see text] and Cl(-)-[Formula: see text] types under major group of [Formula: see text]) and the hydrogeochemical signatures (Na(+)/Cl(-), >1 and [Formula: see text]/Cl(-), originally fresh quality, but is subsequently modified to brackish by the influences of anthropogenic and marine sources, which also supported by the statistical analysis. The concentrations of total dissolved solids (TDS), TH, Mg(2+), Na(+), K(+), [Formula: see text], Cl(-), [Formula: see text], and F(-) are above the recommended limits prescribed for drinking water in many locations. The quality of groundwater is of mostly moderate in comparison with the salinity hazard versus sodium hazard, the total salt concentration versus percent sodium, the residual sodium carbonate, and the magnesium hazard, but is of mostly suitable with respect to the permeability index for irrigation. The higher concentrations of TDS, TH, [Formula: see text], Cl(-), and [Formula: see text

  10. Hydrogeochemical analysis and evaluation of groundwater quality in the Gadilam river basin, Tamil Nadu, India

    Indian Academy of Sciences (India)

    M V Prasanna; S Chidambaram; A Shahul Hameed; K Srinivasamoorthy

    2011-02-01

    Water samples were collected from different formations of Gadilam river basin and analyzed to assess the major ion chemistry and suitability of water for domestic and drinking purposes. Chemical parameters of groundwater such as pH, electrical conductivity (EC), total dissolved solids (TDS), Sodium (Na+), Potassium (K+), Calcium (Ca+), Magnesium (Mg+), Bicarbonate (HCO$_{3}^{-}$), Sulphate (SO$_{4}^-$), Phosphate (PO$_{4}^{-}$) and Silica (H4SiO4) were determined. The geochemical study of the aquatic systems of the Gadilam river basin show that the groundwater is near-acidic to alkaline and mostly oxidizing in nature. Higher concentration of Sodium and Chloride indicates leaching of secondary salts and anthropogenic impact by industry and salt water intrusion. Spatial distribution of EC indicates anthropogenic impact in the downstream side of the basin. The concentration levels of trace metals such as Iron (Fe), Lead (Pb), Nickel (Ni), Bromide (Br), Iodide (I) and Aluminium (Al) have been compared with the world standard. Interpretation of data shows that some trace metals such as Al, Ni and Pb exceed the acceptable limit of world standard. Geophysical study was carried out to identify the weathered zone in the hard rock and contaminated zone by anthropogenic impact in the downstream of river Gadilam. A few of the groundwater samples in the study area were found to be unsuitable for domestic and drinking purposes.

  11. Contaminated groundwater characterization at the Chalk River Laboratories, Ontario, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Schilk, A.J.; Robertson, D.E.; Thomas, C.W.; Lepel, E.A. [Pacific Northwest National Lab., Richland, WA (United States); Champ, D.R.; Killey, R.W.D.; Young, J.L.; Cooper, E.L. [Chalk River Labs., Chalk River, Ontario (Canada)

    1993-03-01

    The licensing requirements for the disposal of low-level radioactive waste (10 CFR 61) specify the performance objectives and technical requisites for federal and commercial land disposal facilities, the ultimate goal of which is to contain the buried wastes so that the general population is adequately protected from harmful exposure to any released radioactive materials. A major concern in the operation of existing and projected waste disposal sites is subterranean radionuclide transport by saturated or unsaturated flow, which could lead to the contamination of groundwater systems as well as uptake by the surrounding biosphere, thereby directly exposing the general public to such materials. Radionuclide transport in groundwater has been observed at numerous commercial and federal waste disposal sites [including several locations within the waste management area of Chalk River Laboratories (CRL)], yet the physico-chemical processes that lead to such migration are still not completely understood. In an attempt to assist in the characterization of these processes, an intensive study was initiated at CRL to identify and quantify the mobile radionuclide species originating from three separate disposal sites: (a) the Chemical Pit, which has received aqueous wastes containing various radioisotopes, acids, alkalis, complexing agents and salts since 1956, (b) the Reactor Pit, which has received low-level aqueous wastes from a reactor rod storage bay since 1956, and (c) the Waste Management Area C, a thirty-year-old series of trenches that contains contaminated solid wastes from CRL and various regional medical facilities. Water samples were drawn downgradient from each of the above sites and passed through a series of filters and ion-exchange resins to retain any particulate and dissolved or colloidal radionuclide species, which were subsequently identified and quantified via radiochemical separations and gamma spectroscopy. These groundwaters were also analyzed for anions

  12. Effects of hydraulic frac fluids and formation waters on groundwater microbial communities

    Science.gov (United States)

    Krueger, Martin; Jimenez, Nuria

    2017-04-01

    Shale gas is being considered as a complementary energy resource to other fossil fuels. Its exploitation requires using advanced drilling techniques and hydraulic stimulation (fracking). During fracking operations, large amounts of fluids (fresh water, proppants and chemicals) are injected at high pressures into the formations, to create fractures and fissures, and thus to release gas from the source rock into the wellbore. The injected fluid partly remains in the formation, while up to 40% flows back to the surface, together with reservoir waters, sometimes containing dissolved hydrocarbons, high salt concentrations, etc. The aim of our study was to investigate the potential impacts of frac or geogenic chemicals, frac fluid, formation water or flowback on groudnwater microbial communities. Laboratory experiments under in situ conditions (i.e. at in situ temperature, high pressure) were conducted using groundwater samples from three different locations. Series of microcosms containing R2 broth medium or groundwater spiked with either single frac chemicals (including biocides), frac fluids, artificial reservoir water, NaCl, or different mixtures of reservoir water and frac fluid (to simulate flowback) were incubated in the dark. Controls included non-amended and non-inoculated microcosms. Classical microbiological methods and molecular analyses were used to assess changes in the microbial abundance, community structure and function in response to the different treatments. Microbial communities were quite halotolerant and their growth benefited from low concentrations of reservoir waters or salt, but they were negatively affected by higher concentrations of formation waters, salt, biocides or frac fluids. Changes on the microbial community structure could be detected by T-RFLP. Single frac components like guar gum or choline chloride were used as substrates, while others like triethanolamine or light oil distillate hydrogenated prevented microbial growth in

  13. Effects of hydraulic frac fluids and formation waters on groundwater microbial communities

    Science.gov (United States)

    Jiménez, Núria; Krüger, Martin

    2015-04-01

    Shale gas is being considered as a complementary energy resource to other fossil fuels. Its exploitation requires using advanced drilling techniques and hydraulic stimulation (fracking). During fracking operations, large amounts of fluids (fresh water, proppants and chemicals) are injected at high pressures into the formations, to create fractures and fissures, and thus to release gas from the source rock into the wellbore. The injected fluid partly remains in the formation, while up to 40% flows back to the surface, together with reservoir waters, sometimes containing dissolved hydrocarbons, high salt concentrations, etc. The aim of our study was to investigate the potential impacts of frac or geogenic chemicals, frac fluid, formation water or flowback on groudnwater microbial communities. Laboratory experiments under in situ conditions (i.e. at in situ temperatures, with high pressure, etc.) were conducted using groundwater samples from three different locations. Series of microcosms (3 of each kind) containing R2 broth medium or groundwater spiked with either single frac chemicals (including biocides), frac fluids, artificial reservoir water, NaCl, or different mixtures of reservoir water and frac fluid (to simulate flowback) were incubated in the dark. Controls included non-amended and non-inoculated microcosms. Classical microbiological methods and molecular analyses were used to assess changes in the microbial abundance, community structure and function in response to the different treatments. Microbial communities were quite halotolerant and their growth benefited from low concentrations of reservoir waters or salt, but they were negatively affected by higher concentrations of formation waters, salt, biocides, frac fluids or flowback. Changes on the microbial community structure could be detected by T-RFLP. Single frac components like guar gum or choline chloride could be used as substrates, while the effects of others like triethanolamine or light oil

  14. Groundwater Discharge and Salinity Sources to an Impaired Major River in a Semi-Arid Coastal Region: Nueces River, Texas

    Science.gov (United States)

    Murgulet, V.; Murgulet, D.; Hay, R.

    2015-12-01

    Nueces River, an impaired stream located on the South Texas Gulf coast area, has shown water quality degradation due to to increased salinity levels in areas adjacent to the Calallen saltwater reservoir dam. This study investigates the role of submarine groundwater discharge in delivering increased salt contents to the river and how the subsurface hydrology is affected by the presence of a salt barrier (i.e. saltwater dam) which separates the tidal and non-tidal parts of the Nueces river basin. Thus, a combination of resistivity profiling and elemental and stable isotope geochemistry methods has been applied to portions of the river located downstream (tidal) and upstream (non-tidal) of the dam. Preliminary data show that salinity levels gradually increases at the river bank indicating that groundwater is likely a source of solutes to the river in the upper, non-tidal portion. The presence of vertical upwelling of conductive groundwater plumes is also revealed by marine resistivity profiles collected along the river. Different sampling during the spring and summer of 2014 show higher concentration values of major ions (i.e., calcium, magnesium, sodium, potassium, chloride, etc.) and salinity of pore water for the upstream river at several locations while it remains relatively constant for bottom- and surface water. In addition, because the groundwater and porewater have slightly lower pH values, a shift to more acidic surface water accompanied by some increases in dissolved major ion concentrations and salinity suggest that groundwater might represent a source of increased salt content in the upper portion of the river. On the other hand, downstream dissolved major ion concentrations generally decrease in pore- and bottom water from spring to summer and are correlated with decreases in salinity while surface water becomes more saline with an increase in major ions. Therefore, these preliminary data indicate different hydrology systems of the two portions of the

  15. Shallow ground-water quality beneath rice areas in the Sacramento Valley, California, 1997

    Science.gov (United States)

    Dawson, Barbara J.

    2001-01-01

    , and non-agricultural purposes. All pesticide concentrations were below state and federal 2000 drinking-water standards. The relation of the ground-water quality to natural processes and human activities was tested using statistical methods (Spearman rank correlation, Kruskal?Wallis, or rank-sum tests) to determine whether an influence from rice land-use or other human activities on ground-water chemistry could be identified. The detection of pesticides in 89 percent of the wells sampled indicates that human activities have affected shallow ground-water quality. Concentrations of dissolved solids and inorganic constituents that exceeded state or federal 2000 drinking-water standards showed a statistical relation to geomorphic unit. This is interpreted as a relation to natural processes and variations in geology in the Sacramento River Basin; the high concentrations of dissolved solids and most inorganic constituents did not appear to be related to rice land use. No correlation was found between nitrate concentration and pesticide occurrence, indicating that an absence of high nitrate concentrations is not a predictor of an absence of pesticide contamination in areas with reducing ground-water conditions in the Sacramento Valley. Tritium concentrations, pesticide detections, stable isotope data, and dissolved-solids concentrations suggest that shallow ground water in the ricegrowing areas of the Sacramento Valley is a mix of recently recharged ground water containing pesticides, nitrate, and tritium, and unknown sources of water that contains high concentrations of dissolved solids and some inorganic constituents and is enriched in oxygen-18. Evaporation of applied irrigation water, which leaves behind salt, accounts for some of the elevated concentrations of dissolved solids. More work needs to be done to understand the connections between the land surface, shallow ground water, deep ground water, and the drinking-water supplies in the Sacramento Valley.

  16. Thermodynamic properties of gases dissolved in electrolyte solutions.

    Science.gov (United States)

    Tiepel, E. W.; Gubbins, K. E.

    1973-01-01

    A method based on perturbation theory for mixtures is applied to the prediction of thermodynamic properties of gases dissolved in electrolyte solutions. The theory is compared with experimental data for the dependence of the solute activity coefficient on concentration, temperature, and pressure; calculations are included for partial molal enthalpy and volume of the dissolved gas. The theory is also compared with previous theories for salt effects and found to be superior. The calculations are best for salting-out systems. The qualitative feature of salting-in is predicted by the theory, but quantitative predictions are not satisfactory for such systems; this is attributed to approximations made in evaluating the perturbation terms.

  17. Mobilization of arsenic, lead, and mercury under conditions of sea water intrusion and road deicing salt application

    Science.gov (United States)

    Sun, Hongbing; Alexander, John; Gove, Brita; Koch, Manfred

    2015-09-01

    Water geochemistry data from complexly designed salt-solution injection experiments in the laboratory, coastal aquifers of Bangladesh and Italy, taken from the literature, and two salted watersheds of New Jersey, US were collected and analyzed to study the geochemical mechanisms that mobilize As, Pb, and Hg under varied salting conditions. Overall, increased NaCl-concentrations in aquifers and soil are found to increase the release of Pb and Hg into the water. Reducing environments and possible soil dispersion by hydrated Na+ are found to lead to an increase of As-concentration in water. However, the application of a pure NaCl salt solution in the column injection experiment was found to release less As, Pb, and Hg initially from the soil and delay their concentration increase, when compared to the application of CaCl2 and NaCl mixed salts (at 6:4 weight ratio). The concentration correlation dendrogram statistical analyses of the experimental and field data suggest that the release of As, Hg, and Pb into groundwater and the soil solution depends not only on the salt level and content, but also on the redox condition, dissolved organic matter contents, competitiveness of other ions for exchange sites, and source minerals. With the ongoing over-exploration of coastal aquifers from increased pumping, continued sea-level rise, and increased winter deicing salt applications in salted watersheds of many inland regions, the results of this study will help understand the complex relation between the concentrations of As, Pb, and Hg and increased salt level in a coastal aquifer and in soils of a salted watershed.

  18. Fate and Transport of Road Salt During Snowmelt Through a Calcareous Fen: Kampoosa Bog, Stockbridge, Massachusetts

    Science.gov (United States)

    Rhodes, A. L.; Guswa, A. J.; Pufall, A.

    2007-12-01

    Kampoosa Bog is the largest and most ecologically diverse calcareous lake-basin fen in Massachusetts. Situated within a 4.7 km2 drainage basin, the open fen (approx. 20 acres) consists of a floating mat of sedges (incl. Carex aquatilis and Cladium mariscoides) that overlie peat and lake clay deposits. Mineral weathering of marble bedrock within the drainage basin supplies highly alkaline ground and surface waters to the fen basin. The natural chemistry has been greatly altered by road salt runoff from the Massaschusetts Turnpike, and in question is whether disturbance from the Turnpike and a gas pipline has facilitated aggressive growth by the invasive species Phragmites australis. Considered to be one of the most significant rare species habitats in the state, Massachusetts has designated Kampoosa Bog an Area of Critical Environmental Concern, and a committee representing several local, regional, and state agencies, organizations, and citizens manages the wetland. The purpose of this study is to characterize the hydrologic and chemical response of the wetland during snowmelt events to understand the fate and movement of road salt (NaCl). Concentrations of Na and Cl in the fen groundwater are greatest close to the Turnpike. Concentrations decrease with distance downstream but are still greatly elevated relative to sites upstream of the Turnpike. During snowmelt events, the fen's outlet shows a sharp rise in Na and Cl concentrations at the onset of melting that is soon diluted by the added meltwater. The Na and Cl flux, however, is greatest at peak discharge, suggesting that high-flow events are significant periods of export of dissolved salts from the fen. Pure dissolution of rock salt produces an equal molar ratio between Na and Cl, and sodium and chloride imbalances in stream and ground waters suggest that ~20% of the Na is stored on cation exchange sites within the peat. The largest imbalances between Na and Cl occur deeper within the peat, where the peat is

  19. Evidence of the Earliest Salt Production Found in China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Being critical in the development of the human civilization, the ancient salt-making has been an important research issue for both historians and archaeologists. Since salt dissolves in water, it is difficult to tell whether the salt in archaeological samples was caused by human production of salt or underground water. So how to judge the existence of salt production has been a world-wide problem in archaeology and archaeometry.

  20. The Role of Groundwater and Reservoir Interaction in Salinity Distribution in a Saline Area in the Northeastern Part of Thailand

    Science.gov (United States)

    Seeboonruang, U.

    2012-12-01

    Salinity is a process by which the concentration of soluble salt in soil and water increases. Human activities can, however, disrupt this natural equilibrium by changing the distribution of salt in the environment. Reservoirs have played a number of crucial roles in the development of human civilization. The main purposes of reservoirs are to prevent floods, to supply water for domestic consumption, to generate electricity, and to irrigate farmlands. Despite various benefits, reservoirs could bring about adverse environmental and social impacts. Infiltration or leakage from man-made reservoirs or dams could cause the change of the groundwater level, thus forcing the deposited salt onto the soil surface and/or waterways. Until now, it is nevertheless unclear as to how the operation and maintenance of reservoirs could impact in a saline soil area physically, environmentally, and/or socially. The purpose of this research is therefore to assess the impacts of reservoirs on groundwater and salinity levels in a saline soil area in the northeastern part of Thailand. Saline soil can be found in many regions of Thailand, particularly in the northeast of Thailand where the Maha Sarakham Foundation, which is composed of imbedded salt rock layers, is the main source of salinity in the region. The salinity accumulation on the surface soil is influenced by the brackish groundwater upward flow and evaporation processes. The study area is located in Nakhon Panom Province in the northeastern part of Thailand along the Great Mekong River and has a total area of approximately 1,300 km2. The yearly evaporation rate in this region is as high as the annual evaporation rate. A reservoir was constructed in the low-lying floodplain area of the Nam Kam basin and started operation since a few years ago. The reservoir is located right in the middle of the floodplain where flood always occurs every rainy season. Groundwater levels are measured and groundwater samples are collected for p

  1. Controls on selenium distribution and mobilization in an irrigated shallow groundwater system underlain by Mancos Shale, Uncompahgre River Basin, Colorado, USA

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Taylor J.; Mast, M. Alisa; Thomas, Judith; Keith, Gabrielle

    2016-10-01

    Elevated selenium (Se) concentrations in surface water and groundwater have become a concern in areas of the Western United States due to the deleterious effects of Se on aquatic ecosystems. Elevated Se concentrations are most prevalent in irrigated alluvial valleys underlain by Se-bearing marine shales where Se can be leached from geologic materials into the shallow groundwater and surface water systems. This study presents groundwater chemistry and solid-phase geochemical data from the Uncompahgre River Basin in Western Colorado, an irrigated alluvial landscape underlain by Se-rich Cretaceous marine shale. We analyzed Se species, major and trace elements, and stable nitrogen and oxygen isotopes of nitrate in groundwater and aquifer sediments to examine processes governing selenium release and transport in the shallow groundwater system. Groundwater Se concentrations ranged from below detection limit (< 0.5 μg L{sup −1}) to 4070 μg L{sup −1}, and primarily are controlled by high groundwater nitrate concentrations that maintain oxidizing conditions in the aquifer despite low dissolved oxygen concentrations. High nitrate concentrations in non-irrigated soils and nitrate isotopes indicate nitrate is largely derived from natural sources in the Mancos Shale and alluvial material. Thus, in contrast to areas that receive substantial NO{sub 3} inputs through inorganic fertilizer application, Se mitigation efforts that involve limiting NO{sub 3} application might have little impact on groundwater Se concentrations in the study area. Soluble salts are the primary source of Se to the groundwater system in the study area at-present, but they constitute a small percentage of the total Se content of core material. Sequential extraction results indicate insoluble Se is likely composed of reduced Se in recalcitrant organic matter or discrete selenide phases. Oxidation of reduced Se species that constitute the majority of the Se pool in the study area could be a potential

  2. Tracer attenuation in groundwater

    Science.gov (United States)

    Cvetkovic, Vladimir

    2011-12-01

    The self-purifying capacity of aquifers strongly depends on the attenuation of waterborne contaminants, i.e., irreversible loss of contaminant mass on a given scale as a result of coupled transport and transformation processes. A general formulation of tracer attenuation in groundwater is presented. Basic sensitivities of attenuation to macrodispersion and retention are illustrated for a few typical retention mechanisms. Tracer recovery is suggested as an experimental proxy for attenuation. Unique experimental data of tracer recovery in crystalline rock compare favorably with the theoretical model that is based on diffusion-controlled retention. Non-Fickian hydrodynamic transport has potentially a large impact on field-scale attenuation of dissolved contaminants.

  3. Salt minerals and waters from soils in Konya and Kenya

    NARCIS (Netherlands)

    Vergouwen, L.

    1981-01-01

    This study deals with the relation between the mineralogical composition of salt assemblages and the composition of groundwaters from which these salts precipitated. A comparison was made between salts and waters sampled in the Konya Basin in Turkey and waters sampled in three different regions in K

  4. Groundwater recharge and agricultural contamination

    Science.gov (United States)

    Böhlke, J.K.

    2002-01-01

    Agriculture has had direct and indirect effects on the rates and compositions of groundwater recharge and aquifer biogeochemistry. Direct effects include dissolution and transport of excess quantities of fertilizers and associated materials and hydrologic alterations related to irrigation and drainage. Some indirect effects include changes in water-rock reactions in soils and aquifers caused by increased concentrations of dissolved oxidants, protons, and major ions. Agrilcultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO3-, N2, Cl, SO42-, H+, P, C, K, Mg, Ca, Sr, Ba, Ra, and As, as well a wide variety of pesticides and other organic compounds. For reactive contaminants like NO3-, a combination of chemical, isotopic, and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. Groundwater records derived from multi-component hydrostratigraphic data can be used to quantify recharge rates and residence times of water and dissolved contaminants, document past variations in recharging contaminant loads, and identify natural contaminant-remediation processes. These data indicate that many of the world's surficial aquifers contain transient records of changing agricultural contamination from the last half of the 20th century. The transient agricultural groundwater signal has important implications for long-term trends and spatial heterogeneity in discharge.

  5. Soluble salt sources in medieval porous limestone sculptures: A multi-isotope (N, O, S) approach

    Energy Technology Data Exchange (ETDEWEB)

    Kloppmann, W., E-mail: w.kloppmann@brgm.fr [BRGM, Direction des Laboratoires, Unité Isotopes, BP 6009, F-45060 Orléans cedex 2 (France); Rolland, O., E-mail: olivierrolland@wanadoo.fr [Montlouis-sur-Loire (France); Proust, E.; Montech, A.T. [BRGM, Direction des Laboratoires, Unité Isotopes, BP 6009, F-45060 Orléans cedex 2 (France)

    2014-02-01

    The sources and mechanisms of soluble salt uptake by porous limestone and the associated degradation patterns were investigated for the life-sized 15th century “entombment of Christ” sculpture group located in Pont-à-Mousson, France, using a multi-isotope approach on sulphates (δ{sup 34}S and δ{sup 18}O) and nitrates (δ{sup 15}N and δ{sup 18}O). The sculpture group, near the border of the Moselle River, is within the potential reach of capillary rise from the alluvial aquifer. Chemical analyses show a vertical zonation of soluble salts with a predominance of sulphates in the lower parts of the statues where crumbling and blistering prevail, and higher concentrations of nitrates and chloride in the high parts affected by powdering and efflorescence. Isotope fingerprints of sulphates suggest a triple origin: (1) the lower parts are dominated by capillary rise of dissolved sulphate from the Moselle water with characteristic Keuper evaporite signatures that progressively decreases with height; (2) in the higher parts affected by powdering the impact of atmospheric sulphur becomes detectable; and (3) locally, plaster reparations impact the neighbouring limestone through dissolution and re-precipitation of gypsum. Nitrogen and oxygen isotopes suggest an organic origin of nitrates in all samples. N isotope signatures are compatible with those measured in the alluvial aquifer of the Moselle River further downstream. This indicates contamination by sewage or organic fertilisers. Significant isotopic contrasts are observed between the different degradation features depending on the height and suggest historical changes of nitrate sources. - Highlights: • We use S, N and O isotopes to distinguish salt sources in limestone sculptures. • Vertical zonation of degradation is linked to capillary rise and air pollution. • Sulphate salts in lower parts are derived from river/groundwater. • Sulphate salts in higher parts show signature of air pollution. • Nitrates

  6. Characterization of saline groundwater across the coastal aquifer of Israel as resource for desalination

    Science.gov (United States)

    Stein, Shaked; Russak, Amos; Sivan, Orit; Yechieli, Yospeh; Oren, Yoram; Kasher, Roni

    2015-04-01

    In arid countries with access to marine water seawater desalination is becoming an important water source in order to deal with the water scarcity and population growth. Seawater reverse osmosis (RO) facilities use open seawater intake, which requires pretreatment processes to remove particles in order to avoid fouling of the RO membrane. In small and medium size desalination facilities, an alternative water source can be saline groundwater in coastal aquifers. Using saline groundwater from boreholes near the shore as feed water may have the advantage of natural filtration and low organic content. It will also reduce operation costs of pretreatment. Another advantage of using groundwater is its availability in highly populated areas, where planning of large RO desalination plants is difficult and expensive due to real-estate prices. Pumping saline groundwater underneath the freshwater-seawater interface (FSI) might shift the interface towards the sea, thus rehabilitating the fresh water reservoirs in the aquifer. In this research, we tested the potential use of saline groundwater in the coastal aquifer of Israel as feed water for desalination using field work and desalination experiments. Specifically, we sampled the groundwater from a pumping well 100 m from the shore of Tel-Aviv and sea water from the desalination plant in Ashqelon, Israel. We used an RO cross flow system in a pilot plant in order to compare between the two water types in terms of permeate flux, permeate flux decline, salt rejection of the membrane and the fouling on the membrane. The feed, brine and fresh desalinated water from the outlet of the desalination system were chemically analyzed and compared. Field measurements of dissolved oxygen, temperature, pH and salinity were also conducted in situ. Additionally, SDI (silt density index), which is an important index for desalination, and total organic carbon that has a key role in organic fouling and development of biofouling, were measured and

  7. Groundwater arsenic and fluoride in Rajnandgaon District, Chhattisgarh, northeastern India

    Science.gov (United States)

    Patel, Khageshwar Singh; Sahu, Bharat Lal; Dahariya, Nohar Singh; Bhatia, Amarpreet; Patel, Raj Kishore; Matini, Laurent; Sracek, Ondra; Bhattacharya, Prosun

    2017-07-01

    The groundwater of Ambagarh Chouki, Rajnandgaon, India, shows elevated levels of As and F-, frequently above the WHO guidelines. In this work, the concentrations of As, F-, Na+, Mg2+, Ca2+, Cl-, SO4 2-, HCO3 -, Fe, dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in the groundwater of Ambagarh Chouki are described. The sources of dissolved components in the groundwater are investigated using the cluster and factor analysis. Five factors have been identified and linked to processes responsible for the formation of groundwater chemistry. High concentrations of dissolved As seems to be linked to high concentrations of DOC, suggesting reductive dissolution of ferric oxyhydroxides as arsenic mobilization process. Fluoride is found in shallow depth water, presumably as a consequence of evaporation of water and removal of Ca2+ by precipitation of carbonates.

  8. Variability of surface-water quantity and quality and shallow groundwater levels and quality within the Rio Grande Project Area, New Mexico and Texas, 2009–13

    Science.gov (United States)

    Driscoll, Jessica M.; Sherson, Lauren R.

    2016-03-15

    Drought conditions during the study period of January 1, 2009, to September 30, 2013, caused a reduction in surface-water releases from water-supply storage infrastructure of the Rio Grande Project, which led to changes in surface-water and groundwater (conjunctive) use in downstream agricultural alluvial valleys. Surface water and groundwater in the agriculturally dominated alluvial Rincon and Mesilla Valleys were investigated in this study to measure the influence of drought and subsequent change in conjunctive water use on quantity and quality of these water resources. In 2013, the U.S. Geological Survey, in cooperation with the New Mexico Environment Department and the New Mexico Interstate Stream Commission, began a study to (1) calculate dissolved-solids loads over the study period at streamgages in the study area where data are available, (2) assess the temporal variability of dissolved-solids loads at and between each streamgage where data are available, and (3) relate the spatiotemporal variability of shallow groundwater data (groundwater levels and quality) within the alluvial valleys of the study area to spatiotemporal variability of surface-water data over the study period. This assessment included the calculation of surface-water dissolved-solids loads at streamgages as well as a mass-balance approach to measure the change in salt load between these streamgages. Bimodal surface-water discharge data led to a temporally-dynamic volumetric definition of release and nonrelease seasons. Continuous surface-water discharge and water-quality data from three streamgages on the Rio Grande were used to calculate daily dissolved-solids loads over the study period, and the results were aggregated annually and seasonally. Results show the majority of dissolved-solids loading occurs during release season; however, decreased duration of the release season over the 5-year study period has resulted in a decrease of the total annual loads at each streamgage

  9. Modelling electrical conductivity of groundwater using an adaptive neuro-fuzzy inference system

    NARCIS (Netherlands)

    B. Tutmez (Bulent); Z. Hatipoglu (Z.); U. Kaymak (Uzay)

    2006-01-01

    textabstractElectrical conductivity is an important indicator for water quality assessment. Since the composition of mineral salts affects the electrical conductivity of groundwater, it is important to understand the relationships between mineral salt composition and electrical conductivity. In this

  10. Analysing Groundwater Using the 13C Isotope

    Science.gov (United States)

    Awad, Sadek

    The stable isotope of the carbon atom (13C) give information about the type of the mineralisation of the groundwater existing during the water seepage and about the recharge conditions of the groundwater. The concentration of the CO2(aq.) dissolved during the infiltration of the water through the soil's layers has an effect on the mineralisation of this water. The type of the photosynthesis's cycle (C-3 or C-4 carbon cycle) can have a very important role to determine the conditions (closed or open system) of the mineralisation of groundwater. The isotope 13C of the dissolved CO2 in water give us a certain information about the origin and the area of pollution of water. The proportion of the biogenic carbon and its percentage in the mineralisation of groundwater is determined by using the isotope 13C.

  11. Geomorphic aspects of groundwater flow

    Science.gov (United States)

    LaFleur, Robert G.

    The many roles that groundwater plays in landscape evolution are becoming more widely appreciated. In this overview, three major categories of groundwater processes and resulting landforms are considered: (1) Dissolution creates various karst geometries, mainly in carbonate rocks, in response to conditions of recharge, geologic setting, lithology, and groundwater circulation. Denudation and cave formation rates can be estimated from kinetic and hydraulic parameters. (2) Groundwater weathering generates regoliths of residual alteration products at weathering fronts, and subsequent exhumation exposes corestones, flared slopes, balanced rocks, domed inselbergs, and etchplains of regional importance. Groundwater relocation of dissolved salts creates duricrusts of various compositions, which become landforms. (3) Soil and rock erosion by groundwater processes include piping, seepage erosion, and sapping, important agents in slope retreat and headward gully migration. Thresholds and limits are important in many chemical and mechanical groundwater actions. A quantitative, morphometric approach to groundwater landforms and processes is exemplified by selected studies in carbonate and clastic terrains of ancient and recent origins. Résumé Les rôles variés joués par les eaux souterraines dans l'évolution des paysages deviennent nettement mieux connus. La revue faite ici prend en considération trois grandes catégories de processus liés aux eaux souterraines et les formes associées: (1) La dissolution crée des formes karstiques variées, surtout dans les roches carbonatées, en fonction des conditions d'alimentation, du cadre géologique, de la lithologie et de la circulation des eaux souterraines. Les taux d'érosion et de formation des grottes peuvent être estimés à partir de paramètres cinétiques et hydrauliques. (2) L'érosion par les eaux souterraines donne naissance à des régolites, résidus d'altération sur des fronts d'altération, et l'exhumation r

  12. The characteristics of the main dissolved salt and the desalination experiments in Terra-Cotta Warriors and Horses of Emperor Qin Shihuang Mausolesum Site%秦始皇帝陵土遗址可溶盐特征与脱盐试探

    Institute of Scientific and Technical Information of China (English)

    吕功煊; 张尚新; 钱玲; 夏寅; 胡红岩; 容波; 周铁

    2015-01-01

    介绍了秦始皇兵马俑可溶盐赋存特征和主要盐害类型特点。土遗址盐害部位主要存在的可溶盐是Na2SO4和NaCl。除此之外,样品可溶盐中还含有少量钾盐及微量硝酸盐,而微溶盐分主要为CaSO4以及少量镁盐。Na2SO4对土遗址损害的表现形式与NaCl有很大不同,它具有超强的穿透、迁移能力及结晶破坏能力,盐害多表现为酥碱、起甲和块状剥落。硫酸盐的破坏与Na2SO4存赋温度、环境温度及湿度的变化密切相关,易引发盐害区域为32.4℃以下的温度区间的温度变化及40%以上的干湿度循环交变。用模拟试块模拟了盐害发生的现象和可溶盐运移规律,并选取半封闭式博物馆遗址秦始皇兵马俑K9901陪葬坑,应用适用于土遗址本体盐害防治的新型脱盐材料进行了脱盐示范试验,取得了良好的脱盐结果。%Inthis paper, the characteristics of the main dissolved salt elements and their contents in Terra-Cotta Warriors and Horses of Emperor Qin Shihuang Mausoleum Site were presented. Na2SO4 and NaCl are main deterioration salts, in addition, small amount of K and Ca sulfate and nitrate were also found. Amount of Mg sulfate was detected. The demage of Na2SO4 was very different from that of NaCl. Its super penetration, migration and destruction abilities led to much more serious demages, the salt demage styles were commonly salt efflorescence, falking and piece falling. The demage results of Na2SO4 salt were highly dependent on its containing temperature, the variation of environmental temperature and humidity. The easy demage condition regions are 32.4℃ and the humidity variation around 40%. The mimc of salt demage was carried out in the laboratory conditions, and the regualtions of salt migration was presented. The relatively permitted-critical relative temperature and humidity for the protection of the earthen sites are suggested. A starch grafted polyacrylamide

  13. Effects of irrigated agroecosystems: 2. Quality of soil water and groundwater in the southern High Plains, Texas

    Science.gov (United States)

    Scanlon, B. R.; Gates, J. B.; Reedy, R. C.; Jackson, W. A.; Bordovsky, J. P.

    2010-09-01

    Trade-offs between water-resource depletion and salinization need to be understood when promoting water-conservative irrigation practices. This companion paper assesses impacts of groundwater-fed irrigation on soil water and groundwater quality using data from the southern High Plains (SHP). Unsaturated zone soil samples from 13 boreholes beneath irrigated agroecosystems were analyzed for water-extractable anions. Salt accumulation in soils varies with irrigation water quality, which ranges from low salinity in the north (median Cl: 21 mg/L) to higher salinity in the south (median Cl: 180 mg/L). Large Cl bulges under irrigated agroecosystems in the south are similar to those under natural ecosystems, but they accumulated over decades rather than millennia typical of natural ecosystems. Profile peak Cl concentrations (1200-6400 mg/L) correspond to irrigation efficiencies of 92-98% with respect to drainage and are attributed to deficit irrigation with minimal flushing. Perchlorate (ClO4) also accumulates under irrigated agroecosystems, primarily from irrigation water, and behaves similarly to Cl. Most NO3-N accumulation is below the root zone. Groundwater total dissolved solids (TDS) have increased by ≤960 mg/L and NO3-N by ≤9.4 mg/L since the early 1960s. Mobilization of salts that have accumulated under irrigated agroecosystems is projected to degrade groundwater much more in the future because of the essentially closed-basin status of the aquifer, with discharge occurring primarily through irrigation pumpage. TDS are projected to increase by an additional 2200 mg/L (median), ClO4 by 21 μg/L, and NO3-N by 52 mg/L. Water and salt balances should be considered in irrigation management in order to minimize salinization issues.

  14. Fingerprinting groundwater salinity sources in the Gulf Coast Aquifer System, USA

    Science.gov (United States)

    Chowdhury, Ali H.; Scanlon, Bridget R.; Reedy, Robert C.; Young, Steve

    2017-07-01

    Understanding groundwater salinity sources in the Gulf Coast Aquifer System (GCAS) is a critical issue due to depletion of fresh groundwater and concerns for potential seawater intrusion. The study objective was to assess sources of groundwater salinity in the GCAS using ˜1,400 chemical analyses and ˜90 isotopic analyses along nine well transects in the Texas Gulf Coast, USA. Salinity increases from northeast (median total dissolved solids (TDS) 340 mg/L) to southwest (median TDS 1,160 mg/L), which inversely correlates with the precipitation distribution pattern (1,370- 600 mm/yr, respectively). Molar Cl/Br ratios (median 540-600), depleted δ2H and δ18O (-24.7‰, -4.5‰) relative to seawater (Cl/Br ˜655 and δ2H, δ18O 0‰, 0‰, respectively), and elevated 36Cl/Cl ratios (˜100), suggest precipitation enriched with marine aerosols as the dominant salinity source. Mass balance estimates suggest that marine aerosols could adequately explain salt loading over the large expanse of the GCAS. Evapotranspiration enrichment to the southwest is supported by elevated chloride concentrations in soil profiles and higher δ18O. Secondary salinity sources include dissolution of salt domes or upwelling brines from geopressured zones along growth faults, mainly near the coast in the northeast. The regional extent and large quantities of brackish water have the potential to support moderate-sized desalination plants in this location. These results have important implications for groundwater management, suggesting a current lack of regional seawater intrusion and a suitable source of relatively low TDS water for desalination.

  15. An assessment of groundwater quality using water quality index in Chennai, Tamil Nadu, India

    OpenAIRE

    I Nanda Balan; Shivakumar, M.; Madan Kumar, P. D.

    2012-01-01

    Context : Water, the elixir of life, is a prime natural resource. Due to rapid urbanization in India, the availability and quality of groundwater have been affected. According to the Central Groundwater Board, 80% of Chennai′s groundwater has been depleted and any further exploration could lead to salt water ingression. Hence, this study was done to assess the groundwater quality in Chennai city. Aim : To assess the groundwater quality using water quality index in Chennai city. Materials and ...

  16. Brackish groundwater in the United States

    Science.gov (United States)

    Stanton, Jennifer S.; Anning, David W.; Brown, Craig J.; Moore, Richard B.; McGuire, Virginia L.; Qi, Sharon L.; Harris, Alta C.; Dennehy, Kevin F.; McMahon, Peter B.; Degnan, James R.; Böhlke, John Karl

    2017-04-05

    in the United States. Previously published digital data relating to brackish groundwater resources were limited to a small number of State- and regional-level studies. Data sources for this assessment ranged from single publications to large datasets and from local studies to national assessments. Geochemical data included concentrations of dissolved solids, major ions, trace elements, nutrients, and radionuclides as well as physical properties of the water (pH, temperature, and specific conductance). Additionally, the database provides selected well information (location, yield, depth, and contributing aquifer) necessary for evaluating the water resource.The assessment was divided into national-, regional-, and aquifer-scale analyses. National-scale analyses included evaluation of the three-dimensional distribution of observed dissolved-solids concentrations in groundwater, the three-dimensional probability of brackish groundwater occurrence, and the geochemical characteristics of saline (greater than or equal to 1,000 mg/L of dissolved solids) groundwater resources. Regional-scale analyses included a summary of the percentage of observed grid cell volume in the region that was occupied by brackish groundwater within the mixture of air, water, and rock for multiple depth intervals. Aquifer-scale analyses focused primarily on four regions that contained the largest amounts of observed brackish groundwater and included a generalized description of hydrogeologic characteristics from previously published work; the distribution of dissolved-solids concentrations; considerations for developing brackish groundwater resources, including a summary of other chemical characteristics that may limit the use of brackish groundwater and the ability of sampled wells producing brackish groundwater to yield useful amounts of water; and the amount of saline groundwater being used in 2010.

  17. Environmental monitoring final report: groundwater chemical analyses

    Energy Technology Data Exchange (ETDEWEB)

    1984-02-01

    This report presents the results of analyses of groundwater qualtiy at the SRC-I Demonstration Plant site in Newman, Kentucky. Samples were obtained from a network of 23 groundwater observation wells installed during previous studies. The groundwater was well within US EPA Interim Primary Drinking Water Standards for trace metals, radioactivity, and pesticides, but exceeded the standard for coliform bacteria. Several US EPA Secondary Drinking Water Standards were exceeded, namely, manganese, color, iron, and total dissolved solids. Based on the results, Dames and Moore recommend that all wells should be sterilized and those wells built in 1980 should be redeveloped. 1 figure, 6 tables.

  18. Influence of geochemical processes on hydrochemistry and irrigation suitability of groundwater in part of semi-arid Deccan Plateau, India

    Science.gov (United States)

    Vasu, Duraisamy; Singh, Surendra Kumar; Tiwary, Pramod; Sahu, Nisha; Ray, Sanjay Kumar; Butte, Pravin; Duraisami, Veppangadu Perumal

    2017-02-01

    Major ion geochemistry was used to characterise the chemical composition of groundwater in part of semi-arid Deccan plateau region to understand the geochemical evolution and to evaluate the groundwater quality for irrigation. The study area comprises peninsular gneissic complex of Archean age, younger granites and basaltic alluvium. Forty-nine georeferenced groundwater samples were collected and analysed for major ions. The ionic sequence based on relative proportions was Na+ > Mg2+ > Ca2+ > SO4 2- > HCO3 - > Cl- > CO3 2- > BO3 3- > K+. High Na+, Mg2+ and Ca2+ were generally associated with basaltic alluvial formation, whereas pH, electrical conductivity (EC) and total dissolved salts (TDS) were found to be higher in granitic formations. High standard deviation for EC, TDS, Na+, Ca2+ and Mg2+ indicated the dispersion of ionic concentration throughout the study area. Four major hydrochemical facies identified were Na-Mg-HCO3 type; Mg-Na-HCO3 type; Na-Mg-Ca-SO4 and Mg-Na-Ca-SO4 type. The graphical plots indicated that the groundwater chemistry was influenced by rock-water interaction, silicate weathering and reverse ion exchange. Sodium-dominated waters might have impeded the hydraulic properties of soils as a result of long-term irrigation.

  19. Hydrogeochemical modeling of groundwater chemical environmental evolution in Hebei Plain

    Institute of Scientific and Technical Information of China (English)

    郭永海; 沈照理; 钟佐燊

    1997-01-01

    Using the hydrogeochemical modeling method, the groundwater chemical environmental problems of the Hebei Plain which involve increasing of hardness and total dissolved solids in piedmont area and mixing of saline water with fresh water in middle-eastern area are studied. The water-rock interactions and mass transfer along a ground-water flow path and in mixing processes are calculated. Thus the evolution mechanisms of the groundwater chemical environment are brought to light.

  20. Role of the bottom sediments immediately beneath the lake water-groundwater interface in the transport and removal of cyanobacteria, cyanophage, and dissolved organic carbon during natural lake-bank filtration at a kettle pond subject to harmful algal blooms

    Science.gov (United States)

    Harvey, R. W.; Metge, D. W.; LeBlanc, D. R.; Underwood, J. C.; Aiken, G.; McCobb, T. D.; Jasperse, J.

    2015-12-01

    Bank filtration has proven to be a sustainable, cost-effective method of removing cyanobacteria and their harmful toxins from surface water during filtration through bottom and aquifer sediments. The biologically active layer of sediments immediately beneath the sediment-water interface (colmation layer) is believed to be particularly important in this process. An in situ experiment was conducted that involved assessing the transport behaviors of bromide (conservative tracer), Synechococcus sp. IU625 (cyanobacterium, 2.6 ± 0.2 µm), AS-1 (tailed cyanophages, 110 nm long), MS2 (coliphages, 26 nm diameter), and carboxylate-modified microspheres (1.7 µm diameter) introduced to the colmation layer using a bag-and-barrel (Lee-type) seepage meter. The constituents were monitored as they advected through the colmation layer and underlying aquifer sediments at Ashumet Pond in Cape Cod, MA, a mesotrophic kettle pond that recharges a portion of a sole-source, drinking water aquifer. Because the pond DOC includes the various cyanotoxins produced during harmful algal bloom senescence, the DOC and aforementioned colloids were tracked concomitantly. The tracer test constituents were monitored as they advected across the pond water-groundwater interface and through the underlying aquifer sediments under natural-gradient conditions past push-points samplers placed at ~30-cm intervals along a 1.2-m-long, diagonally downward flow path. More than 99% of the microspheres, IU625, MS2, AS-1, and ~42% of the pond DOC were removed in the colmation layer (upper 25 cm of poorly sorted bottom sediments) at two test locations characterized by dissimilar seepage rates (1.7 vs. 0.26 m d-1). Retention profiles in recovered core material indicated that >82% of the attached IU625 were in the top 3 cm of bottom sediments. The colmation layer was also responsible for rapid changes in the character of the DOC and was more effective (by 3 orders of magnitude) at removing microspheres than was the

  1. Impact of landfill leachate on the groundwater quality: A case study in Egypt

    Directory of Open Access Journals (Sweden)

    Magda M. Abd El-Salam

    2015-07-01

    Full Text Available Alexandria Governorate contracted an international company in the field of municipal solid waste management for the collection, transport and disposal of municipal solid waste. Construction and operation of the sanitary landfill sites were also included in the contract for the safe final disposal of solid waste. To evaluate the environmental impacts associated with solid waste landfilling, leachate and groundwater quality near the landfills were analyzed. The results of physico-chemical analyses of leachate confirmed that its characteristics were highly variable with severe contamination of organics, salts and heavy metals. The BOD5/COD ratio (0.69 indicated that the leachate was biodegradable and un-stabilized. It was also found that groundwater in the vicinity of the landfills did not have severe contamination, although certain parameters exceeded the WHO and EPA limits. These parameters included conductivity, total dissolved solids, chlorides, sulfates, Mn and Fe. The results suggested the need for adjusting factors enhancing anaerobic biodegradation that lead to leachate stabilization in addition to continuous monitoring of the groundwater and leachate treatment processes.

  2. Hydrochemical investigations for delineating salt-water intrusion into the coastal aquifer of Maharlou Lake, Iran

    Science.gov (United States)

    Jahanshahi, Reza; Zare, Mohammad

    2016-09-01

    Groundwater quality depends on different factors such as geology, lithology, properties of aquifer, land use, the physical condition of boundaries etc. Studying these factors can help users to manage groundwater quality. This study deals with the groundwater quality of an aquifer located in the southeastern part of Maharlou salt lake, Iran. This lake is located in the southeast of Shiraz and is the outlet of Shiraz sewages. Due to overexploitation of groundwater from the aquifer, the gradient of water table is from the lake towards the aquifer and therefore, saline water migrates to the aquifer. The phenomenon of salt water intrusion contributes to the deterioration of groundwater. In this research, groundwater types, maps of iso EC and iso ions, ion exchange in the mixing of fresh and salt water, salinity variation of the groundwater in the profile of well water column, and the salinity-time variation of the groundwater were studied. The gradual increase of the salinity of groundwater with depth from top to down in the aquifer indicates that salt water is located under fresh water. The time variation of physical and chemical parameters in the groundwater discharged from a well shows that the saline water in the bottom of the aquifer moves upward and destroys the quality of groundwater in the study area. Furthermore, Sachoun geological formation formed by evaporate deposits and evaporation from shallow groundwater are two other factors which decrease the groundwater quality.

  3. Prediction of activity coefficients in liquid aerosol particles containing organic compounds, dissolved inorganic salts, and water—Part 2: Consideration of phase separation effects by an X-UNIFAC model

    Science.gov (United States)

    Chang, Elsa I.; Pankow, James F.

    A thermodynamic model is presented for predicting the formation of particulate matter (PM) within an aerosol that contains organic compounds, inorganic salts, and water. Neutral components are allowed to partition from the gas phase to the PM, with the latter potentially composed of both a primarily aqueous ( α) liquid phase and a primarily organic ( β) liquid phase. Partitioning is allowed to occur without any artificial restraints: when both α and β PM phases are present, ionic constituents are allowed to partition to both. X-UNIFAC.2, an extended UNIFAC method based on Yan et al. (1999. Prediction of vapor-liquid equilibria in mixed-solvent electrolyte systems using the group contribution concept. Fluid Phase Equilibria 162, 97-113), was developed for activity coefficient estimation. X-UNIFAC.2 utilizes the standard UNIFAC terms, a Debye-Hückel term, and a virial equation term that represents the middle-range (MR) contribution to activity coefficient effects. A large number (234) of MR parameters are already available from Yan et al. (1999). Six additional MR parameters were optimized here to enable X-UNIFAC.2 to account for interactions between the carboxylic acid group and Na +, Cl -, and Ca 2+. Predictions of PM formation were made for a hypothetical sabinene/O 3 system with varying amounts of NaCl in the PM. Predictions were also made for the chamber experiments with α-pinene/O 3 (and CaCl 2 seed) carried out by Cocker et al. (2001. The effect of water on gas-particle partitioning of secondary organic aerosol. Part I. α-pinene/ozone system. Atmospheric Environment 35, 6049-6072); good agreement between the predicted and chamber-measured PM mass concentrations was achieved.

  4. The Biogeochemistry of Contaminant Groundwater Plumes Arising from Waste Disposal Facilities

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup; Albrechtsen, Hans-Jørgen; Kjeldsen, Peter;

    2014-01-01

    Landfills with solid waste are abundant sources of groundwater pollution all over the world. Old uncontrolled municipal landfills are often large, heterogeneous sources with demolition waste, minor fractions of commercial or industrial waste, and organic waste from households. Strongly anaerobic...... leachate with a high content of dissolved organic carbon, salts, and ammonium, as well as specific organic compounds and metals is released from the waste for decades or centuries. Landfill leachate plume hosts a variety of biogeochemical processes, which is the key to understand the significant potential...... at landfill sites. Finally, the potential chemical or ecological impact from landfills located in former wetlands or near surface water bodies may deserve attention in future studies....

  5. The Biogeochemistry of Contaminant Groundwater Plumes Arising from Waste Disposal Facilities

    DEFF Research Database (Denmark)

    Bjerg, Poul Løgstrup; Albrechtsen, Hans-Jørgen; Kjeldsen, Peter

    2014-01-01

    and the heterogeneity of the source may create a variable leaching pattern and maybe also multiple plumes; and (4) significant natural attenuation of xenobiotic organic compounds occurs, but the complexity of leachate plumes with respect to compounds (inorganic and xenobiotic organic compounds) and biogeochemical...... leachate with a high content of dissolved organic carbon, salts, and ammonium, as well as specific organic compounds and metals is released from the waste for decades or centuries. Landfill leachate plume hosts a variety of biogeochemical processes, which is the key to understand the significant potential......Landfills with solid waste are abundant sources of groundwater pollution all over the world. Old uncontrolled municipal landfills are often large, heterogeneous sources with demolition waste, minor fractions of commercial or industrial waste, and organic waste from households. Strongly anaerobic...

  6. Will salt repositories be dry?

    Science.gov (United States)

    Bredehoeft, John D.

    The National Academy of Science committee that considered geologic disposal of nuclear waste in the mid-1950s recommended salt as a repository medium, partly because of its high thermal conductivity and because it was believed to be “dry” (perhaps the appropriate thought is “impermeable”). Certainly, the fact that Paleozoic salt deposits exist in many parts of t h e world is evidence for very low rates of dissolution by moving groundwater. The fact that the dissolution rates were so small led many scientists to the conclusion that the salt beds were nearly impermeable. The major source of brine within the salt beds was thought to be fluid inclusions within salt crystals, which could migrate through differential solution toward a source of high heat. The idea that salt was uniformly “dry” was revised when exploratory drilling in the vicinity of the Waste Isolation Pilot Plant (WIPP) in New Mexico encountered brines within the Castile Formation, an evaporite deposit below the Salado Formation. The brine reservoirs were thought to be isolated pockets of brine in an otherwise “impermeable” salt section.

  7. Assessment of ammonium, nitrate, phosphate, and heavy metal pollution in groundwater from Amik Plain, southern Turkey.

    Science.gov (United States)

    Ağca, Necat; Karanlık, Sema; Ödemiş, Berkant

    2014-09-01

    Amik Plain is one of the most important agricultural areas of Turkey. Because the groundwater resources have been used not only for irrigation but also for drinking purpose, groundwater resources play a vital role in this area. However, there exist no or a very limited number of studies on groundwater quality and its physicochemical and heavy metal composition for Amik Plain. This study aimed to assess groundwater of Amik Plain in terms of human health and suitability for irrigation based on physicochemical variables, heavy metals, and their spatial distribution. A total of 92 groundwater samples were collected from wells and were analyzed for temperature (T), salt content (SC), dissolved oxygen (DO), ammonium (NH4(+)), nitrate (NO3(-)), and phosphorus (P) and such heavy metals as cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), and zinc (Zn). The temperature, SC, DO, NH4(+), and NO3(-) parameters were measured in situ immediately with YSI Professional plus instrument (Pro Plus). Water depth was taken from owner of the wells. Heavy metal analyses were carried out in triplicate using inductively coupled atomic emission spectrometer (ICP-AES). The ICP-AES was calibrated for all the metals by running different concentrations of standard solutions. Descriptive statistical analyses were calculated to characterize distribution of physicochemical properties and heavy metal contents of groundwater. Correlation analysis was used to assess the possible relationships among heavy metals and physicochemical properties of the groundwater. Spatial variability in groundwater parameters were determined by geostatistical methods. Result shows that the highest and lowest coefficient of variation occurred for NO3(-) and T, respectively. Mean water table depth was 92.1 m, and only 12 of all the samples exceeded the desirable limit of 50 mg/L for NO3(-) content. The metal concentrations showed a dominance in the order of Fe >

  8. Salt concentrations during water production resulting from CO2 storage

    DEFF Research Database (Denmark)

    Walter, Lena; Class, Holger; Binning, Philip John

    2014-01-01

    present in the saline aquifer. The brine can be displaced over large areas and can reach shallower groundwater resources. High salt concentrations could lead to a degradation of groundwater quality. For water suppliers the most important information is whether and how much salt is produced at a water...... production well. In this approach the salt concentrations at water production wells depending on different parameters are determined for the assumption of a 2D model domain accounting for groundwater flow. Recognized ignorance resulting from grid resolution is qualitatively studied and statistical...... polynomial chaos expansion (aPC) [1]. The aPC is applied in this work to provide probabilities and risk values for salt concentrations at the water production well. Mixing in the aquifer has a key influence on the salt concentration at the well. Dispersion and diffusion are the relevant processes for mixing...

  9. 溶浸作用下难溶盐岩力学特性弱化及细观机制研究%MECHANICAL PROPERTY WEAKENING AND THE MESO-MECHANISM OF HARD DISSOLVED SALT ROCK SOAKED IN BRINE

    Institute of Scientific and Technical Information of China (English)

    杨晓琴; 梁卫国; 于艳梅; 张传达; 于伟东; 赵阳升

    2014-01-01

    leaching mining of salt deposits and salt cavern construction for oil and gas storage and other related engineering practice.%岩石材料的宏观力学特性与其内部细观结构演化有十分密切的关系,对典型难溶盐岩钙芒硝在盐溶液溶浸环境下力学特性弱化和细观结构演化进行研究,初步揭示其力学特性弱化的细观机制。研究发现:在盐溶液溶浸作用下,由于矿体胶结物中亲水性矿物吸水膨胀崩解、钙芒硝中硫酸盐的溶解、化学反应离子交换、氯离子侵蚀损伤等因素的作用,钙芒硝孔隙率随“溶液浓度”和时间的变化而非线性演化,从而导致力学特性严重弱化。在盐溶液中溶浸20 d,钙芒硝强度弱化系数低至0.1~0.2。由于钙芒硝矿体内泥质胶结成分的水理水化作用,泥质部分膨胀或崩解,钙芒硝矿体变形表现出应变软化与韧性破坏特征。细观结构演化结果表明,盐溶液溶浸作用下,难溶钙芒硝孔、裂隙演化缓慢,但在淡水溶液中孔隙演化速度是半饱和与饱和溶液中的数倍甚至数百倍。淡水中溶浸48 h后孔隙率高达16.62%,是原始状态孔隙率的9倍;半饱和盐溶液溶浸48 h后,孔隙率是原始状态的3倍,而饱和溶液溶浸48 h后,孔隙率增幅仅为2.8%。孔隙率变化主要是由于钙芒硝矿体中硫酸盐的溶解和结晶,胶结物成分(主要为伊利石、蒙脱石)的水理、膨胀,这也是钙芒硝力学特性弱化的根本原因。本研究对深入认识可溶岩(包括钙芒硝)物理力学特性弱化,并指导盐类矿床原位溶浸开采及层状盐岩溶腔油气储库建造等相关工程实践,具有重要理论意义与应用价值。

  10. Nitrate in groundwater of the United States, 1991-2003

    Science.gov (United States)

    Burow, Karen R.; Nolan, Bernard T.; Rupert, Michael G.; Dubrovsky, Neil M.

    2010-01-01

    An assessment of nitrate concentrations in groundwater in the United States indicates that concentrations are highest in shallow, oxic groundwater beneath areas with high N inputs. During 1991-2003, 5101 wells were sampled in 51 study areas throughout the U.S. as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) program. The well networks reflect the existing used resource represented by domestic wells in major aquifers (major aquifer studies), and recently recharged groundwater beneath dominant land-surface activities (land-use studies). Nitrate concentrations were highest in shallow groundwater beneath agricultural land use in areas with well-drained soils and oxic geochemical conditions. Nitrate concentrations were lowest in deep groundwater where groundwater is reduced, or where groundwater is older and hence concentrations reflect historically low N application rates. Classification and regression tree analysis was used to identify the relative importance of N inputs, biogeochemical processes, and physical aquifer properties in explaining nitrate concentrations in groundwater. Factors ranked by reduction in sum of squares indicate that dissolved iron concentrations explained most of the variation in groundwater nitrate concentration, followed by manganese, calcium, farm N fertilizer inputs, percent well-drained soils, and dissolved oxygen. Overall, nitrate concentrations in groundwater are most significantly affected by redox conditions, followed by nonpoint-source N inputs. Other water-quality indicators and physical variables had a secondary influence on nitrate concentrations.

  11. Influence of groundwater on the degradation of irrigated soils in a semi-arid region, the inner delta of the Niger River, Mali

    Science.gov (United States)

    Valenza, A.; Grillot, J. C.; Dazy, J.

    2000-08-01

    The problem of soil degradation through alkalinization/salinization in an irrigated area with a semi-arid climate was examined in the inner delta of the Niger River, Mali, by the study of groundwater hydraulics and hydrochemistry in an area recharged by irrigation water. On the basis of data analysis on various scales, it is concluded that the current extent of the surface saline soils is due to a combination of three factors: (1) the existence of ancient saline soils (solonchaks) resulting from the creation of a broad sabkha west of the former course of the Niger River, now called the Fala of Molodo. These saline crusts were gradually deposited during the eastward tilting of the tectonic block that supports the Niger River; (2) the irrigation processes during the recent reflooding of the Fala of Molodo (river diversion in 1950). These used very poorly mineralized surface water but reintroduced into the alluvial groundwater system - generally of a low permeability (K=10-6 m s-1) - salts derived from the ancient solonchaks; and (3) the redeposition of the dissolved salts on the surface due to the intense evapotranspiration linked to the present Sahelian climate. In this context, only efficient artificial draining of subsurface alluvial groundwater can eliminate most of the highly mineralized flow and thus reduce the current saline deposits.

  12. groundwater contribution to crop water requirement groundwater ...

    African Journals Online (AJOL)

    eobe

    Keywords: Groundwater, water table, capillary rise, soil type, waterleaf, ... GROUNDWATER CONTRIBUTION TO WATERLEAF (TALINUM TRIANGULARE) IN OXISOLS, I. J. ... Nutritionally, ... information to facilitate increased crop production,.

  13. Modeling of Groundwater Quantity and Quality Management, Nile Valley, Egypt

    Science.gov (United States)

    Owlia, R.; Fogg, G. E.

    2012-12-01

    Groundwater levels have been rising in the Luxor area of Egypt due to increased agricultural irrigation following the construction of the Aswan High Dam (AHD) in 1970. This has led to soil and groundwater salinity problems caused by increasing evapotranspiration from shallower water table, as well as the degradation of historical monuments whose foundations are weakening by capillary rise of water into the columns and stonework. While similar salinity problems exist elsewhere in the world (e.g., San Joaquin Valley of California), we hypothesize that as long as groundwater discharge to the Nile River continues and serves as a sink for the salt, the regional salt balance will be manageable and will not lead to irreversible salinization of soils. Further, we hypothesize that if a groundwater system such as this one becomes overdrafted, thereby cutting off groundwater discharge to the River, the system salt balance will be less manageable and possibly non-sustainable. With groundwater flow modeling we are investigating approaches for managing the irrigation and groundwater levels so as to eliminate water stresses on Egyptian monuments and antiquities. Consequences of possible actions for managing the water table through groundwater pumping and alternative irrigation practices will be presented. Moreover, through the use of high resolution modeling of system heterogeneity, we will simulate the long term salt balance of the system under various scenarios, including the overdraft case. The salt source will be a function of groundwater discharge to the surface via bare-soil evaporation and crop transpiration. The built-in heterogeneity will account for dispersion, fast transport in connected media and slow mass transfer between aquifer and aquitard materials. Key Words: Groundwater, modeling, water quality, sustainability, salinity, irrigated agriculture, Nile aquifer.

  14. Cultural Meromixis: the Influence of Road Salt Deicers on Two Urban Kettle Lakes

    Science.gov (United States)

    Koretsky, C.; Sibert, R.; Wyman, D. A.; Griffey, D.; Krishnamurthy, R. V.

    2014-12-01

    The increasing global use of road salt deicers has led to an influx of salts, particularly NaCl and CaCl2, into urban surface waters. This influx has led to documented salinization of drinking water supplies, as well as damage to ecosystems. There is an increasing recognition that the influx of road salt deciers may also influence the physical mixing of lakes, with dramatic consequences for lake biogeochemistry. In this study, the water column chemistry of two kettle lakes in urban Kalamazoo, MI, USA was monitored for over a year. Woods Lake, an ~9.7 ha, 14 m max depth lake, receives most water from storm water sewers, whereas nearby Asylum Lake, an ~19.8 ha, 15.8 m max depth lake, is primarily groundwater fed. The water columns of both lakes are strongly redox stratified, but exhibit some significant differences in water chemistry. The input of road salt has caused Woods Lake to transition to meromixis, with permanently anoxic bottom waters and significant accumulations of dissolved Mn(II), Fe(II), NH3, PO4-3 and sometimes HS- in the hypolimnion. In contrast, Asylum Lake appears to be monomictic, with turnover occurring in fall, but not spring. During most seasons, the hypolimnion of Asylum Lake has significant levels of dissolved Mn(II), NH3, PO4-3, and sometimes HS-, but dissolved Fe(II) remains below detection limits. A comparison of δ18O and δD with the local meteoric water line demonstrates that both lakes undergo significant evaporation. Woods Lake is considerably more influenced by evaporation than Asylum Lake, presumably due to the longer residence time of water in Woods Lake. The longer residence time, together with the smaller volume of water in Woods Lake, likely explains the more rapid transition to meromixis compared to Asylum Lake. This study demonstrates that road salt deicers can significantly influence the biogeochemistry and physical function of urban lakes, and in some cases can result in dimictic lakes transitioning to cultural meromixis.

  15. Estimating Groundwater Quality Changes Using Remotely Sensed Groundwater Storage and Multivariate Regression

    Science.gov (United States)

    Gibbons, A.; Thomas, B. F.; Famiglietti, J. S.

    2014-12-01

    Global groundwater dependence is likely to increase with continued population growth and climate-driven freshwater redistribution. Recent groundwater quantity studies have estimated large-scale aquifer depletion rates using monthly water storage variations from NASA's Gravity Recovery and Climate Experiment (GRACE) mission. These innovative approaches currently fail to evaluate groundwater quality, integral to assess the availability of potable groundwater resources. We present multivariate relationships to predict total dissolved solid (TDS) concentrations as a function of GRACE-derived variations in water table depth, dominant land use, and other physical parameters in two important aquifer systems in the United States: the High Plains aquifer and the Central Valley aquifer. Model evaluations were performed using goodness of fit procedures and cross validation to identify general model forms. Results of this work demonstrate the potential to characterize global groundwater potability using remote sensing.

  16. PRIMARY ANALYSIS ON GROUNDWATER, SOIL MOISTURE AND SALINITY IN FUKANG OASIS OF SOUTHERN JUNGGAR BASIN

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Soil salinity is the most important factor affecting vegetation distribution, and the secondary salinizationhas affected the development of oasis agriculture. In arid areas the spatial variation of soil moisture and salt content is marked-ly affected by groundwater, irrational irrigation in artificial oasis. By analyzing the soil moisture, salt content and groundwa-ter table in different areas of old oasis, new oasis and desert in Fukang Oasis, it is shown that topography and land useare main factors affecting the change of groundwater table, the redistribution of soil moisture and salt content. When undis-turbed by human, the groundwater table rises from mountain to belt of ground water spillage, the groundwater table risesmightily in plain because of the artificial irrigation, and the secondary salinization of soil is very serious. In oasis the ground-water table raises compared with that in the natural desert at the same latitude. In old oasis of upper reaches of river salthas not been concentrated too much in rhizosphere because this area is the belt of groundwater drainage, soil texture iscoarse, the groundwater table is very low, and the salt in soil is drained into the groundwater. The new oasis has beenthe areas of salt accumulation because of the artificial irrigation, the salt content in soil is higher than that in old oasis,so some cultivated fields here had to be thrown out because of the serious secondary salinization.

  17. Salt reduction in sheeted dough: A successful technological approach.

    Science.gov (United States)

    Diler, Guénaëlle; Le-Bail, Alain; Chevallier, Sylvie

    2016-10-01

    The challenge of reducing the salt content while maintaining shelf life, stability and acceptability of the products is major for the food industry. In the present study, we implemented processing adjustments to reduce salt content while maintaining the machinability and the saltiness perception of sheeted dough: the homogeneous distribution of a layer of encapsulated salt grains on the dough during the laminating process. During sheeting, for an imposed deformation of 0.67, the final strain remained unchanged around 0.50 for salt reduction below 50%, and then, increased significantly up to 0.53 for a dough without salt. This increase is, in fine, positive regarding the rolling process since the decrease of salt content induces less shrinkage of dough downstream, which is the main feature to be controlled in the process. Moreover, the final strain was negatively correlated to the resistance to extension measured with a texture analyzer, therefore providing a method to evaluate the machinability of the dough. From these results, a salt reduction of 25% was achieved by holding 50% of the salt in the dough recipe to maintain the dough properties and saving 25% as salt grains to create high-salted areas that would enhance the saltiness perception of the dough. The distributor mounted above the rollers of the mill proved to be able to distribute evenly salt grains at a calculated step of the rolling out process. An innovative method based on RX micro-tomography allowed to follow the salt dissolving and to demonstrate the capability of the coatings to delay the salt dissolving and consequently the diffusion of salt within the dough piece. Finally, a ranking test on the salted perception of different samples having either an even distribution of encapsulated salt grains, a single layer of salt grains or a homogeneous distribution of salt, demonstrated that increasing the saltiness perception in salt-reduced food product could be achieved by a technological approach

  18. Cl/Br ratios and chlorine isotope evidences for groundwater salinization and its impact on groundwater arsenic, fluoride and iodine enrichment in the Datong basin, China

    Energy Technology Data Exchange (ETDEWEB)

    Li, Junxia; Wang, Yanxin, E-mail: yx.wang@cug.edu.cn; Xie, Xianjun

    2016-02-15

    In order to identify the salinization processes and its impact on arsenic, fluoride and iodine enrichment in groundwater, hydrogeochemical and environmental isotope studies have been conducted on groundwater from the Datong basin, China. The total dissolved solid (TDS) concentrations in groundwater ranged from 451 to 8250 mg/L, and 41% of all samples were identified as moderately saline groundwater with TDS of 3000–10,000 mg/L. The results of groundwater Cl concentrations, Cl/Br molar ratio and Cl isotope composition suggest that three processes including water-rock interaction, surface saline soil flushing, and evapotranspiration result in the groundwater salinization in the study area. The relatively higher Cl/Br molar ratio in groundwater from multiple screening wells indicates the contribution of halite dissolution from saline soil flushed by vertical infiltration to the groundwater salinization. However, the results of groundwater Cl/Br molar ratio model indicate that the effect of saline soil flushing practice is limited to account for the observed salinity variation in groundwater. The plots of groundwater Cl vs. Cl/Br molar ratio, and Cl vs δ{sup 37}Cl perform the dominant effects of evapotranspiration on groundwater salinization. Inverse geochemical modeling results show that evapotranspiration may cause approximately 66% loss of shallow groundwater to account for the observed hydrochemical pattern. Due to the redox condition fluctuation induced by irrigation activities and evapotranspiration, groundwater salinization processes have negative effects on groundwater arsenic enrichment. For groundwater iodine and fluoride enrichment, evapotranspiration partly accounts for their elevation in slightly saline water. However, too strong evapotranspiration would restrict groundwater fluoride concentration due to the limitation of fluorite solubility. - Highlights: • Natural high arsenic, fluoride and iodine groundwater co-occur with saline water.

  19. Phosphate salts

    Science.gov (United States)

    ... levels that are too high, and for preventing kidney stones. They are also taken for treating osteomalacia (often ... But intravenous phosphate salts should not be used. Kidney stones (nephrolithiasis). Taking potassium phosphate by mouth might help ...

  20. Salt cookbook

    CERN Document Server

    Saha, Anirban

    2015-01-01

    If you are a professional associated with system and infrastructure management, looking at automated infrastructure and deployments, then this book is for you. No prior experience of Salt is required.

  1. Assessment of dissolved-solids loading to the Colorado River in the Paradox Basin between the Dolores River and Gypsum Canyon, Utah

    Science.gov (United States)

    Shope, Christopher L.; Gerner, Steven J.

    2014-01-01

    Salinity loads throughout the Colorado River Basin have been a concern over recent decades due to adverse impacts on population, natural resources, and regional economics. With substantial financial resources and various reclamation projects, the salt loading to Lake Powell and associated total dissolved-solids concentrations in the Lower Colorado River Basin have been substantially reduced. The Colorado River between its confluence with the Dolores River and Lake Powell traverses a physiographic area where saline sedimentary formations and evaporite deposits are prevalent. However, the dissolved-solids loading in this area is poorly understood due to the paucity of water-quality data. From 2003 to 2011, the U.S. Geological Survey in cooperation with the U.S. Bureau of Reclamation conducted four synoptic sampling events to quantify the salinity loading throughout the study reach and evaluate the occurrence and impacts of both natural and anthropogenic sources. The results from this study indicate that under late-summer base-flow conditions, dissolved-solids loading in the reach is negligible with the exception of the Green River, and that variations in calculated loads between synoptic sampling events are within measurement and analytical uncertainties. The Green River contributed approximately 22 percent of the Colorado River dissolved-solids load, based on samples collected at the lower end of the study reach. These conclusions are supported by water-quality analyses for chloride and bromide, and the results of analyses for the stable isotopes of oxygen and deuterium. Overall, no significant sources of dissolved-solids loading from tributaries or directly by groundwater discharge, with the exception of the Green River, were identified in the study area.

  2. Speciation of Dissolved Cadmium

    DEFF Research Database (Denmark)

    Holm, Peter Engelund; Andersen, Sjur; Christensen, Thomas Højlund

    1995-01-01

    Equilibrium dialysis and ion exchange methods, as well as computer calculations (GEOCHEM), were applied for speciation of dissolved cadmium (Cd) in test solutions and leachate samples. The leachate samples originated from soil, compost, landfill waste and industrial waste. The ion exchange (IE...

  3. Geophysical, geochemical and hydrological analyses of water-resource vulnerability to salinization: case of the Uburu-Okposi salt lakes and environs, southeast Nigeria

    Science.gov (United States)

    Ukpai, S. N.; Okogbue, C. O.

    2017-06-01

    Until this study, the location and depth of the saline units in Uburu-Okposi salt lake areas and environs have been unknown. This study aimed at delineating the saline lithofacies and dispersal configurations to water bodies, using electrical geophysical methods such as constant separation traversing (CST) and vertical electrical sounding (VES). Results showed weathered zones that represent aquifers mostly at the fourth geoelectric layer: between upper layered aquitards and underlying aquitards at depths 30-140 m. Lateral distribution of resistivity variance was defined by the CST, whereas the VES tool, targeted at low-resistivity zones, detected isolated saline units with less than 10 ohm-m at depths generally >78 m. The saline lithofacies were suspected to link freshwater zones via shear zones, which steer saline water towards the salt lakes and influence the vulnerability of groundwater to salinization. The level of salinization was verified by water sampling and analysis, and results showed general alkaline water type with a mean pH of 7.66. Water pollution was indicated: mean total dissolved solids (TDS) 550 mg/l, electrical conductivity (EC) 510 μS/cm, salinity 1.1‰, Cl- 200 mg/l, N03 -35.5 mg/l, Na+ 19.6 mg/l and Ca2+ 79.3 mg/l. The salinity is controlled by NaCl salt, as deduced from correlation analysis using the software package Statistical Product for Service Solutions (SPSS). Generally, concentrations of dissolved ions in the water of the area are enhanced via mechanisms such as evaporation, dissociation of salts, precipitation run off and leaching of dissolved rock minerals.

  4. Radioactive content in groundwater in the island of Tenerife (Canary Islands); Contenido radioactivo en aguas en aguas subterraneas de la Isla de Tenerifie (Canarias)

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Perez, M.; Duarte-Rodriguez, X.; Rodriguez-Perestelo, N.; Catalan-Acosta, A.; Fernandez- De Aldecoa, J. C.; Hernandez Armas, J.

    2013-07-01

    At present the groundwater in Tenerife is still the main resource to meet the demands of all kinds. Currently, due to the salt content, groundwater is treated using reversible electrodialysis desalination systems before drinking it. (Author)

  5. Ecology and living conditions of groundwater fauna

    Energy Technology Data Exchange (ETDEWEB)

    Thulin, Barbara (Geo Innova AB (Sweden)); Hahn, Hans Juergen (Arbeitsgruppe Grundwasseroekologie, Univ. of Koblenz-Landau (Germany))

    2008-09-15

    This report presents the current state of ecological knowledge and applied research relating to groundwater. A conceptual picture is given of groundwater fauna occurrence in regard to Swedish environmental conditions. Interpretation features for groundwater fauna and applications are outlined. Groundwater is one of the largest and oldest limnic habitats populated by a rich and diverse fauna. Both very old species and species occurring naturally in brackish or salt water can be found in groundwater. Groundwater ecosystems are heterotrophic; the fauna depends on imports from the surface. Most species are meiofauna, 0.3-1 mm. The food chain of groundwater fauna is the same as for relatives in surface water and salt water. Smaller animals graze biofilms and detritus, larger animals act facutatively as predators. A difference is that stygobiotic fauna has become highly adapted to its living space and tolerates very long periods without food. Oxygen is a limiting factor, but groundwater fauna tolerates periods with low oxygen concentrations, even anoxic conditions. For longer periods of time a minimum oxygen requirement of 1 mg/l should be fulfilled. Geographic features such as Quaternary glaciation and very old Pliocene river systems are important for distribution patterns on a large spatial scale, but aquifer characteristics are important on a landscape scale. Area diversity is often comparable to surface water diversity. However, site diversity is low in groundwater. Site specific hydrological exchange on a geological facies level inside the aquifer, e.g. porous, fractured and karstic aquifers as well as the hyporheic zone, controls distribution patterns of groundwater fauna. For a better understanding of controlling factors indicator values are suggested. Different adequate sampling methods are available. They are representative for the aquifer, but a suitable number of monitoring wells is required. The existence of groundwater fauna in Sweden is considered as very

  6. Study of variation in groundwater quality in a coastal aquifer in north-eastern Tunisia using multivariate factor analysis

    KAUST Repository

    Charfi, Sihem

    2013-07-01

    This work focuses on the Grombalia aquifer which constitutes the main water resource in Northeast Tunisia, Cap Bon Peninsula. The recharge of this aquifer is ensured mainly by direct infiltration of rainwater through permeable layers. Under semi-arid climatic conditions and increasing water demand for irrigation, about 80% of the Grombalia aquifer system shows different vulnerabilities to anthropogenic activities. The total dissolved solids values range from 0.75 to 5.6g/l.Isotopic characterization with stable isotopes (δ2H and δ18O) of Grombalia aquifer system identified geochemistry processes that control water chemistry. In addition, the multivariate statistical technique (Principal Component Analysis) was used to identify the origin, the recharge mode and geochemical processes controlling groundwater quality. The principal reactions responsible for the hydrochemical evolution in the Grombalia groundwater fall into three categories: (1) denitrification process; (2) dissolution of salts; and (3) irrigation return flow process. Tritium data in groundwater from the study area suggest the existence of pre1950 and post1960 recharge. © 2012 Elsevier Ltd and INQUA.

  7. Selenium in groundwater and its contribution towards daily dietary Se intake under different hydrogeological zones of Punjab, India

    Science.gov (United States)

    Dhillon, Karaj S.; Dhillon, Surjit K.

    2016-02-01

    More than 750 groundwater samples collected from different hydrological zones of Punjab state in India were analysed for selenium and some quality parameters to determine suitability of groundwater for irrigation and drinking purpose. Selenium content varied from 0.01 to 35.6 μg L-1. Average Se content in groundwater was the highest in Northeastern Siwalik foothill zone (NSFZ) followed by Central zone (CZ) and Southwestern zone (SWZ). Majority of the water samples contained water contained >20 μg Se L-1 which is considered unsuitable for irrigation of crops. On the basis of pH, 42% of the samples were unfit for drinking in SWZ, 41% in CZ and 6% in NSFZ. Only in SWZ, 24% of the samples with high total dissolved salts were unfit for drinking and 18% unfit for irrigation purpose due to high EC. Selenium content in groundwater was inversely related to depth of water and the degree of relationship was higher for NSFZ (r = -0.342∗∗) followed by CZ (r = -0.157∗) and SWZ (r = -0.126∗). Depending on the amount of water consumed from 2 to 5 L, average Se intake varied from 1.66 to 6.39 μg d-1 and its contribution towards the recommended daily Se allowance ranged from 3.0% to 11.6% for women and 2.4% to 9.1% for men. Among the grain samples, 94% of wheat and 46% of rice contained Se above the deficiency limit of 100 μg kg-1. Thus, the residents in the study area primarily consuming wheat grains and drinking groundwater are getting adequate supply of Se. Among the materials tested for decreasing Se from drinking waters, scrap iron fillings showed potential for commercial use.

  8. Groundwater Waters

    Directory of Open Access Journals (Sweden)

    Ramón Llamas

    1999-10-01

    Full Text Available The groundwaters released through springs constituted a basic element for the survival and progressive development of human beings. Man came to learn how to take better advantage of these waters by digging wells, irrigation channels, and galleries. Nevertheless, these activities do not require cooperation nor the collective agreement of relatively large groups of people, as in the case of creating the necessary structures to take advantage of the resources of surfacewaters. The construction and operation of these structures was a powerful factor in the birth of an urban or civil society – the designated water civilizations. The difference between people taking advantage of groundwater, quasi-individually, and those of surface water, where people work in a group, has continued to the present day. Whereas earlier, this difference did not bring about any special problems, the technological advances of this century, especially theturbine pump, have led to a spectacular increase in the use of roundwater. This advance has significantly contributed to reducing hunger in the world and has provided potable water in developing countries. However, the almost generalized lack of planning and control in the exploitation of these groundwaters reflects that they are little or badly understood by the managers of water policy in almost every country. As such, problems have occurred which have often become exaggerated, giving rise to water-myths. These problems, though, should be addressed if the aim is the sustainable usage of surface water as well as groundwater. To counter any misconceptions and to seek solutions to the problems, distinct plans of action can be highlighted: educating the public; fomenting a system of participative management and decisive support for the communities of users of subterranean waters; integrating a sufficient number of experts in hydrology in the various water management organizations;and assuring transparency of the data on

  9. Speciation of Dissolved Cadmium

    DEFF Research Database (Denmark)

    Holm, Peter Engelund; Andersen, Sjur; Christensen, Thomas Højlund

    1995-01-01

    Equilibrium dialysis and ion exchange methods, as well as computer calculations (GEOCHEM), were applied for speciation of dissolved cadmium (Cd) in test solutions and leachate samples. The leachate samples originated from soil, compost, landfill waste and industrial waste. The ion exchange (IE...... leachates showed different Cd speciation patterns as expected. Some leachates were dominated by free divalent Cd (1-70%), some by inorganic complexes (1-87%), and some by organic complexes (7-98%)....

  10. Groundwater and security

    NARCIS (Netherlands)

    Conti, K.I.; Kukurić, N.; Gupta, J.; Pahl-Wostl, C.; Bhaduri, A.; Gupta, J.

    2016-01-01

    Humans abstract two hundred times more groundwater than oil, annually. Ironically, the role of groundwater in water management and supply is underappreciated, partially due to its invisibility. By conducting a literature survey and investigating groundwater information databases, this chapter answer

  11. Modelling Urban diffuse pollution in groundwater

    Science.gov (United States)

    Jato, Musa; Smith, Martin; Cundy, Andrew

    2017-04-01

    Diffuse urban pollution of surface and ground waters is a growing concern in many cities and towns. Traffic-derived pollutants such as salts, heavy metals and polycyclic aromatic hydrocarbons (PAHs) may wash off road surfaces in soluble or particulate forms which later drain through soils and drainage systems into surface waters and groundwater. In Brighton, about 90% of drinking water supply comes from groundwater (derived from the Brighton Chalk block). In common with many groundwater sources the Chalk aquifer has been relatively extensively monitored and assessed for diffuse rural contaminants such as nitrate, but knowledge on the extent of contamination from road run-off is currently lacking. This project examines the transfer of traffic-derived contaminants from the road surface to the Chalk aquifer, via urban drainage systems. A transect of five boreholes have been sampled on a monthly basis and groundwater samples analysed to examine the concentrations of key, mainly road run-off derived, hydrocarbon and heavy metal contaminants in groundwater across the Brighton area. Trace concentrations of heavy metals and phenols have been observed in groundwater. Electrical conductivity changes in groundwater have also been used to assess local changes in ionic strength which may be associated with road-derived contaminants. This has been supplemented by systematic water and sediment sampling from urban gully pots, with further sampling planned from drainage and settlement ponds adjacent to major roads, to examine initial road to drainage system transport of major contaminants.

  12. Multiphase CFD modelling of water evaporation and salt precipitation in micro-pores

    NARCIS (Netherlands)

    Twerda, A.; O’Mahoney, T.S.D.; Velthuis, J.F.M.

    2014-01-01

    The precipitation of salt in porous reservoir rocks is an impairment to gas production, particularly in mature fields. Mitigation is typically achieved with regular water washes which dissolve the deposited salt and transport it in the water phase. However, since the process of salt precipitation is

  13. Thermochemical investigation of molten fluoride salts for Generation IV nuclear applications - an equilibrium exercise

    NARCIS (Netherlands)

    Meer, J.P.M. van der

    2006-01-01

    The concept of the Molten Salt Reactor, one of the so-called Generation IV future reactors, is that the fuel, a fissile material, which is dissolved in a molten fluoride salt, circulates through a closed circuit. The heat of fission is transferred to a second molten salt coolant loop, the heat of wh

  14. Estimating 14C groundwater ages in a methanogenic aquifer

    Science.gov (United States)

    Aravena, Ramon; Wassenaar, Leonard I; Plummer, L. Niel

    1995-01-01

    This paper addresses the problem of 14C age dating of groundwaters in a confined regional aquifer affected by methanogenesis. Increasing CH4 concentrations along the groundwater flow system and 13C and 14C isotopic data for dissolved inorganic carbon, dissolved organic carbon, and CH4 clearly show the effect of methanogenesis on groundwater chemistry. Inverse reaction path modeling using NETPATH indicates the predominant geochemical reactions controlling the chemical evolution of groundwater in the aquifer are incongruent dissolution of dolomite, ion exchange, methanogenesis, and oxidation of sedimentary organic matter. Modeling of groundwater 14C ages using NETPATH indicates that a significant part of groundwater in the Alliston aquifer is less than 13,000 years old; however, older groundwater in the range of 15,000–23,000 years is also present in the aquifer. This paper demonstrates that 14C ages calculated using NETPATH, incorporating the effects of methanogenesis on the carbon pools, provide reasonable groundwater ages that were not possible by other isotopic methods.

  15. Fluoride and nitrate removal from brackish groundwaters by batch-mode capacitive deionization.

    Science.gov (United States)

    Tang, Wangwang; Kovalsky, Peter; He, Di; Waite, T David

    2015-11-01

    Capacitive deionization (CDI) is an emerging water desalination technology in which pairs of porous electrodes are electrically charged to remove ionic species from water. In this work, the feasibility of fluoride and nitrate removal from brackish groundwaters by batch-mode CDI was investigated. Initially, the effects of flow rate, initial fluoride concentration, and initial coexisting NaCl concentration on fluoride removal were studied. The steady-state fluoride concentration declined as the initial fluoride concentration decreased while initial NaCl concentration remained constant. Due to the competitive electrosorption between fluoride and chloride for limited pore surface sites, a higher initial chloride concentration resulted in a higher equilibrium dissolved fluoride concentration. A simplified one-dimensional transport model for dual anions was developed and found to reliably describe the dynamic process of removal of both fluoride and chloride ions in CDI cells over a range of well-defined operating conditions. Based on the ability of the model to describe fluoride removal, it was extended to description of nitrate removal from brackish groundwaters and also found to perform well. Thus, the approach to description of ion removal, at least in batch studies, appears robust and should assist in optimization of design and operating conditions such that optimal removal of trace ionic species is achieved even when high background concentrations of salt are present.

  16. Linking groundwater pollution to the decay of 15th-century sculptures in Burgos Cathedral (northern Spain).

    Science.gov (United States)

    Gázquez, Fernando; Rull, Fernando; Medina, Jesús; Sanz-Arranz, Aurelio; Sanz, Carlos

    2015-10-01

    Precipitation of salts-mainly hydrated Mg-Na sulfates-in building materials is rated as one of the most severe threats to the preservation of our architectural and cultural heritage. Nevertheless, the origin of this pathology is still unknown in many cases. Proper identification of the cause of damage is crucial for correct planning of future restoration actions. The goal of this study is to identify the source of the degradation compounds that are affecting the 15th-century limestone sculptures that decorate the retro-choir of Burgos Cathedral (northern Spain). To this end, detailed characterization of minerals by in situ (Raman spectroscopy) and laboratory techniques (XRD, Raman and FTIR) was followed by major elements (ICP and IC) and isotopic analysis (δ(34)S and δ(15)N) of both the mineral phases precipitated on the retro-choir and the dissolved salts in groundwater in the vicinity of the cathedral. The results reveal unequivocal connection between the damage observed and capillary rise of salts-bearing water from the subsoil. The multianalytical methodology used is widely applicable to identify the origin of common affections suffered by historical buildings and masterpieces.

  17. Ground-water quality atlas of Wisconsin

    Science.gov (United States)

    Kammerer, Phil A.

    1981-01-01

    This report summarizes data on ground-water quality stored in the U.S. Geological Survey's computer system (WATSTORE). The summary includes water quality data for 2,443 single-aquifer wells, which tap one of the State's three major aquifers (sand and gravel, Silurian dolomite, and sandstone). Data for dissolved solids, hardness, alkalinity, calcium, magnesium, sodium, potassium, iron, manganese, sulfate, chloride, fluoride, and nitrate are summarized by aquifer and by county, and locations of wells for which data are available 1 are shown for each aquifer. Calcium, magnesium, and bicarbonate (the principal component of alkalinity) are the major dissolved constituents in Wisconsin's ground water. High iron concentrations and hardness cause ground-water quality problems in much of the State. Statewide ,summaries of trace constituent (selected trace metals; arsenic, boron, and organic carbon) concentrations show that these constituents impair water quality in only a few isolated wells.

  18. Assessment of quality and geochemical processes occurring in groundwaters near central air conditioning plant site in Trombay, Maharashtra, India.

    Science.gov (United States)

    Tirumalesh, K; Shivanna, K; Sriraman, A K; Tyagi, A K

    2010-04-01

    This paper summarizes the findings obtained in a monitoring study to understand the sources and processes affecting the quality of shallow and deep groundwater near central air conditioning plant site in Trombay region by making use of physicochemical and biological analyses. All the measured parameters of the groundwaters indicate that the groundwater quality is good and within permissible limits set by (Indian Bureau of Standards 1990). Shallow groundwater is dominantly of Na-HCO(3) type whereas deep groundwater is of Ca-Mg-HCO(3) type. The groundwater chemistry is mainly influenced by dissolution of minerals and base exchange processes. High total dissolved solids in shallow groundwater compared to deeper ones indicate faster circulation of groundwater in deep zone preferably through fissures and fractures whereas groundwater flow is sluggish in shallow zone. The characteristic ionic ratio values and absence of bromide point to the fact that seawater has no influence on groundwater system.

  19. The role of groundwater in the origin of the indurated layered deposits of Arabia Terra, Mars

    Science.gov (United States)

    Andrews-Hanna, J. C.; Wiseman, S. M.; Arvidson, R. E.

    2008-12-01

    Indurated layered deposits of likely sedimentary origin are widely distributed across the Arabia Terra region of Mars. In situ observations by the MER Opportunity rover of one such deposit in Meridiani Planum have been interpreted to represent grains composed of dirty evaporites that have been extensively reworked by fluvial and aeolian processes in a playa environment and diagenetically modified by a fluctuating water table. Stratigraphic relationships, morphological similarities, and spectral evidence suggest a related origin for the many layered deposits throughout Arabia Terra. Isolated intra-crater deposits, erosional outliers, and pedestal craters suggest that the Arabia Terra deposits were once thicker and more widespread than their current extent. We investigate the origin of these sedimentary deposits using global and regional hydrological models, in which groundwater flow is driven by evaporation where the water table intersects the surface and redistribution of that water as low-latitude precipitation. These models predict focused groundwater upwelling and evaporation in Arabia Terra during the Late Noachian to Early Hesperian, driven by its unique topography relative to the adjacent southern highlands and northern lowlands. This hydrological cycle would have brought a steady flux of groundwater to the surface, which upon evaporation, would concentrate any dissolved solutes as a cementing salt that would indurate aeolian material and allow buildup of thick sedimentary deposits. Groundwater upwelling would first be limited to the large craters in the region, resulting in rapid sedimentary infilling by a combination of evaporites and evaporite-cemented clastic material. As the craters were filled, groundwater upwelling would spread out over broad regions of Arabia Terra, producing widespread deposits covering much of the inter-crater plains. The observed distribution and thickness of the deposits agrees with the predictions from the hydrological models

  20. Potential corrosivity of untreated groundwater in the United States

    Science.gov (United States)

    Belitz, Kenneth; Jurgens, Bryant C.; Johnson, Tyler D.

    2016-07-12

    Corrosive groundwater, if untreated, can dissolve lead and other metals from pipes and other components in water distribution systems. Two indicators of potential corrosivity—the Langelier Saturation Index (LSI) and the Potential to Promote Galvanic Corrosion (PPGC)—were used to identify which areas in the United States might be more susceptible to elevated concentrations of metals in household drinking water and which areas might be less susceptible. On the basis of the LSI, about one-third of the samples collected from about 21,000 groundwater sites are classified as potentially corrosive. On the basis of the PPGC, about two-thirds of the samples collected from about 27,000 groundwater sites are classified as moderate PPGC, and about one-tenth as high PPGC. Potentially corrosive groundwater occurs in all 50 states and the District of Columbia.National maps have been prepared to identify the occurrence of potentially corrosive groundwater in the 50 states and the District of Columbia. Eleven states and the District of Columbia were classified as having a very high prevalence of potentially corrosive groundwater, 14 states as having a high prevalence of potentially corrosive groundwater, 19 states as having a moderate prevalence of potentially corrosive groundwater, and 6 states as having a low prevalence of potentially corrosive groundwater. These findings have the greatest implication for people dependent on untreated groundwater for drinking water, such as the 44 million people that are self-supplied and depend on domestic wells or springs for their water supply.

  1. Understanding Your Watershed Fact Sheet: Dissolved Oxygen

    OpenAIRE

    Mesner, Nancy; Geiger, John

    2010-01-01

    Dissolved oxygen describes oxygen molecules which have actually dissolved in water. Sometimes people confuse bubbles in water with dissolved oxygen, but in reality the dissolved form of oxygen cannot be seen.

  2. Salt Lakes of Western Australia - Emissions of natural volatile organic compounds

    Science.gov (United States)

    Sattler, Tobias; Krause, Torsten; Schöler, Heinfried; Kamilli, Katharina; Held, Andreas; Zetzsch, Cornelius; Ofner, Johannes; Junkermann, Wolfgang; Atlas, Elliot

    2013-04-01

    Western Australia is a semi-/arid region that is heavily influenced by global climate change and agricultural land use. The area is known for its many saline lakes with a wide range of hydrogeochemical parameters. This area has been repeatedly investigated since 2006 and consists of ephemeral saline and saline groundwater sourced lakes with a pH reaching from 2.5 to 7.1. The semi-/arid region was originally covered by natural eucalyptus forests, but land-use has changed considerably after large scale deforestation from 1950 to 1970. Today the region is mostly used for growing wheat and live stock. The deforestation led to a rising groundwater table, bringing dissolved salts and minerals to the surface. In the last decades, a concurrent alteration of rain periods has been observed. A reason could be the regional formation of ultra-fine particles that were measured with car-based and airborne instruments around the salt lakes in several campaigns between 2006 and 2011. These ultra-fine particles emitted from the lakes and acting as cloud condensation nuclei can modify cloud microphysics and thus suppress rain events [1]. New data from a campaign in 2012 accentuates the importance of these hyper saline environments for the local climate. Ground-based particle measurements around the salt lakes in 2012 were accompanied by novel chamber experiments directly on the lakes. The 1.5 m³ cubic chamber was constructed from transparent PTFE foil permitting photochemistry within while preventing dilution of the air due to lateral wind transport. This experimental setup allows linking the measured data directly to the chemistry of and above the salt lakes. Another advantage of the PTFE chamber is the enrichment of volatile organic compounds (VOC) that are emitted from salt lakes as possible precursors for the ultra-fine particles. Chamber air was sampled using stainless steel canisters. Sediment, crust and water samples were taken for investigation of potential VOC emissions in

  3. Groundwater and solute transport modeling at Hyporheic zone of upper part Citarum River

    Science.gov (United States)

    Iskandar, Irwan; Farazi, Hendy; Fadhilah, Rahmat; Purnandi, Cipto; Notosiswoyo, Sudarto

    2017-06-01

    Groundwater and surface water interaction is an interesting topic to be studied related to the water resources and environmental studies. The study of interaction between groundwater and river water at the Upper Part Citarum River aims to know the contribution of groundwater to the river or reversely and also solute transport of dissolved ions between them. Analysis of drill logs, vertical electrical sounding at the selected sections, measurement of dissolved ions, and groundwater modeling were applied to determine the flow and solute transport phenomena at the hyporheic zone. It showed the hyporheic zone dominated by silt and clay with hydraulic conductivity range from 10-4∼10-8 m/s. The groundwater flowing into the river with very low gradient and it shows that the Citarum River is a gaining stream. The groundwater modeling shows direct seepage of groundwater into the Citarum River is only 186 l/s, very small compared to the total discharge of the river. Total dissolved ions of the groundwater ranged from 200 to 480 ppm while the river water range from 200 to 2,000 ppm. Based on solute transport modeling it indicates dissolved ions dispersion of the Citarum River into groundwater may occur in some areas such as Bojongsoang-Dayeuh Kolot and Nanjung. This situation would increase the dissolved ions in groundwater in the region due to the contribution of the Citarum River. The results of the research can be a reference for further studies related to the mechanism of transport of the pollutants in the groundwater around the Citarum River.

  4. Land Use Change Impacts on Water, Salt, and Nutrient Cycles: Case Study Semiarid Southern High Plains, Texas, USA (Invited)

    Science.gov (United States)

    Scanlon, B. R.; Reedy, R. C.; Gates, J. B.

    2009-12-01

    to inputs, attributed to deficit irrigation and minimal flushing. Perchlorate (ClO4), primarily from irrigation water, behaves similar to chloride (r=0.69-1.0 in profiles). Large nitrate-N inventories below the root zone represent 96% (median) of profile nitrate-N. Salt inventories under irrigated agroecosystems are correlated with salt concentrations in irrigation water (r=0.94 for chloride). Water fluxes under irrigated agroecosystems (18 to 97 mm/yr, median 48 mm/yr) are mobilizing these contaminants into the Ogallala aquifer. Solute hydrographs show large increases in groundwater salinity by factors of ≤3 for chloride and factors of ≤7 for nitrate-N from the 1970s, attributed to mobilization of salts that accumulated under natural and rainfed ecosystems. Groundwater quality is likely to degrade much more in the future with mobilization of inventories under irrigated agroecosystems with projected increases in total dissolved solids from median values of 1,000 to 6,000 mg/L and nitrate-N from 10 to 110 mg/L. Future water resources management should consider tradeoffs between water, salt, and nutrient balances when promoting various irrigation practices.

  5. Natural Biological Attenuation of Benzene in Groundwater

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Benzene has been found in subsurface unsaturated soil and groundwater beneath a petro-chemical plant. Although the groundwater contained several mg/L of benzene in the area immediately beneath the source, benzene was not detected in monitoring wells approximately 800m down stream. All kinds of physical processes such as adsorption and advection/dispersion are considered to account for the observed attenuation. The results indicated that the attenuation was primarily due to natural biological processes occurring within the aquifer. The evidence for the natural bioremediation of benzene from the groundwater included: (1) analysis of groundwater chemistry, (2) laboratory studies demonstrating benzene biodegradation in aquifer samples, and (3) computer simulations examining benzene transport. Laboratory experiments indicated that for conditions similar to those in the plume, the aerobic degradation of benzene by the naturally occurring microorganisms in the polluted groundwater samples was quite rapid with a half-life time of from 5 to 15 days. In situ analyses indicated the level of dissolved oxygen in the groundwater was over 2mg/L. Thus, oxygen should not limit the biodegradation. In fact, the benzene was also shown to degrade under anaerobic conditions. The results from the modeling simulations indicate that biodegradation is the dominant process influencing attenuation of the benzene.

  6. Relevance of water quality index for groundwater quality evaluation: Thoothukudi District, Tamil Nadu, India

    Science.gov (United States)

    Singaraja, C.

    2017-09-01

    The present hydrogeochemical study was confined to the Thoothukudi District in Tamilnadu, India. A total of 100 representative water samples were collected during pre-monsoon and post-monsoon and analyzed for the major cations (sodium, calcium, magnesium and potassium) and anions (chloride, sulfate, bicarbonate, fluoride and nitrate) along with various physical and chemical parameters (pH, total dissolved salts and electrical conductivity). Water quality index rating was calculated to quantify the overall water quality for human consumption. The PRM samples exhibit poor quality in greater percentage when compared with POM due to dilution of ions and agricultural impact. The overlay of WQI with chloride and EC corresponds to the same locations indicating the poor quality of groundwater in the study area. Sodium (Na %), sodium absorption ratio (SAR), residual sodium carbonate (RSC), residual sodium bicarbonate, permeability index (PI), magnesium hazards (MH), Kelly's ratio (KR), potential salinity (PS) and Puri's salt index (PSI) and domestic quality parameters such as total hardness (TH), temporary, permanent hardness and corrosivity ratio (CR) were calculated. The majority of the samples were not suitable for drinking, irrigation and domestic purposes in the study area. In this study, the analysis of salinization/freshening processes was carried out through binary diagrams such as of mole ratios of {SO}_{ 4}^{ 2- } /Cl- and Cl-/EC that clearly classify the sources of seawater intrusion and saltpan contamination. Spatial diagram BEX was used to find whether the aquifer was in the salinization region or in the freshening encroachment region.

  7. Geochemical Investigations of Groundwater Stability

    Energy Technology Data Exchange (ETDEWEB)

    Bath, Adrian [Intellisci Ltd., Loughborough (United Kingdom)

    2006-05-15

    The report describes geochemical parameters and methods that provide information about the hydrodynamic stability of groundwaters in low permeability fractured rocks that are potential hosts for radioactive waste repositories. Hydrodynamic stability describes the propensity for changes in groundwater flows over long timescales, in terms of flow rates and flow directions. Hydrodynamic changes may also cause changes in water compositions, but the related issue of geochemical stability of a potential repository host rock system is outside the scope of this report. The main approaches to assessing groundwater stability are numerical modelling, measurement and interpretation of geochemical indicators in groundwater compositions, and analyses and interpretations of secondary minerals and fluid inclusions in these minerals. This report covers the latter two topics, with emphasis on geochemical indicators. The extent to which palaeohydrogeology and geochemical stability indicators have been used in past safety cases is reviewed. It has been very variable, both in terms of the scenarios considered, the stability indicators considered and the extent to which the information was explicitly or implicitly used in assessing FEPs and scenarios in the safety cases. Geochemical indicators of hydrodynamic stability provide various categories of information that are of hydrogeological relevance. Information about groundwater mixing, flows and water sources is potentially provided by the total salinity of groundwaters, their contents of specific non-reactive solutes (principally chloride) and possibly of other solutes, the stable isotopic ratio of water, and certain characteristics of secondary minerals and fluid inclusions. Information pertaining directly to groundwater ages and the timing of water and solute movements is provided by isotopic systems including tritium, carbon-14, chlorine-36, stable oxygen and hydrogen isotopes, uranium isotopes and dissolved mobile gases in

  8. Situ treatment of contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    McNab, Jr., Walt W. (Concord, CA); Ruiz, Roberto (Tracy, CA); Pico, Tristan M. (Livermore, CA)

    2001-01-01

    A system for treating dissolved halogenated organic compounds in groundwater that relies upon electrolytically-generated hydrogen to chemically reduce the halogenated compounds in the presence of a suitable catalyst. A direct current is placed across at least a pair, or an array, of electrodes which are housed within groundwater wells so that hydrogen is generated at the cathode and oxygen at the anode. A pump is located within the well housing in which the cathode(s) is(are) located and draws in groundwater where it is hydrogenated via electrolysis, passes through a well-bore treatment unit, and then transported to the anode well(s) for reinjection into the ground. The well-bore treatment involves a permeable cylinder located in the well bore and containing a packed bed of catalyst material that facilitates the reductive dehalogenation of the halogenated organic compounds by hydrogen into environmentally benign species such as ethane and methane. Also, electro-osmatic transport of contaminants toward the cathode also contributes to contaminant mass removal. The only above ground equipment required are the transfer pipes and a direct circuit power supply for the electrodes. The electrode wells in an array may be used in pairs or one anode well may be used with a plurality of cathode wells. The DC current flow between electrode wells may be periodically reversed which controls the formation of mineral deposits in the alkaline cathode well-bore water, as well as to help rejuvenate the catalysis.

  9. Streamflow and estimated loads of phosphorus and dissolved and suspended solids from selected tributaries to Lake Ontario, New York, water years 2012–14

    Science.gov (United States)

    Hayhurst, Brett A.; Fisher, Benjamin N.; Reddy, James E.

    2016-07-20

    , respectively) and orthophosphate (0.17 t/mi2, 0.13 t/mi2, and 0.04 t/mi2, respectively) of the study sites. These results were attributed to a combination of sources, including discharges from wastewater treatment plants, diversions from the New York State Barge Canal, and manure and fertilizers applied to agricultural land. Yields of phosphorus also were high in the Genesee River Basin (0.17 t/mi2) and were presumably associated with nutrient and sediment transport from agricultural land and from streambank erosion. The Salmon and Black Rivers, which drain a substantial amount of forested land and are influenced by large groundwater discharges, had the lowest concentrations and yields of phosphorus and orthophosphate of the study sites.Mean annual yields of dissolved solids were the highest in Irondequoit Creek due to a high percentage of urbanized area in the basin and in Oak Orchard Creek at Kenyonville and in Eighteenmile Creek due to groundwater contributions from the Niagara Escarpment. High yields of dissolved solids of 840 t/mi2, 829 t/mi2, and 715 t/mi2, respectively, from these basins can be attributed to seasonal chloride yields associated with use of road deicing salts. The Niagara Escarpment can produce large amounts of dissolved solids from the dissolution of minerals (a continual process reflected in base flow samples). Groundwater inflows in the Salmon River have very low concentrations of dissolved solids due to minimal bedrock interaction along the Tug Hill Plateau and discharge from the Tug Hill sand and gravel aquifer, which has minimal mineralization.

  10. Behavior of dissolved radiocesium in river water in a forested watershed in Fukushima Prefecture

    Science.gov (United States)

    Tsuji, H.; Nishikiori, T.; Yasutaka, T.; Watanabe, M.; Ito, S.; Hayashi, S.

    2016-10-01

    Dissolved radiocesium concentrations in river water in a high-dose-rate forest watershed in Fukushima Prefecture were investigated under base flow and storm flow conditions. Under base flow conditions, dissolved 137Cs concentrations in water (Bq/L) were relatively high in summer, and these levels were higher than particulate 137Cs concentrations (Bq/L). Under storm flow, particulate 137Cs concentration became dominant as the suspended solid concentration increased. Throughout the monitoring period, dissolved 137Cs concentrations in water (Bq/L) were higher under storm flow than base flow conditions and were positively correlated with runoff intensity. Factors influencing changes in dissolved 137Cs concentrations were investigated by measuring the 137Cs concentration of suspended solid (Bq/kg) and dissolved 137Cs of unsaturated soil water, throughfall, and rainfall, together with other main solute concentrations. The 137Cs concentration per unit weight of suspended solids in river water was not strongly correlated with runoff intensity. Additionally, dissolved 137Cs concentrations of soil water, groundwater, and rainfall were not detected, while higher dissolved 137Cs concentrations were detected in throughfall than river water. K+ concentrations were higher under storm flow than base flow, and dissolved organic carbon increased toward the peak flow rate. These findings suggested that one main factor influencing generation of dissolved 137Cs in the river water was leaching from organic material in flooded areas. However, further investigation is needed to clarify the dominant source of dissolved 137Cs in river water.

  11. The Influence of the Earthquakes on the Compositional Change in Basement Groundwater (on the Example of the South Tatarian Arch)

    Science.gov (United States)

    Ibragimov, R.; Plotnikova, I.

    2009-04-01

    The groundwater composition of deconsolidated zones in the Precambrian crystalline basement of the Volga-Ural anteclise's South Tatarstan Arch was monitored during the period from 1998 to 2003. Chemical and gas compositions of basement waters and fluid levels were monitored in five wells. Other monitoring parameters included total dissolved solids, density and acidity of water and the contents of methane, heavy hydrocarbon gases, hydrogen, helium, carbon dioxide, dissolved organic substances (bitumen carbon) and total nitrogen. In order to study the temporal relationship between variations in water composition and seismic activity, sampling was carried out right after seismic events. Earthquake recording in Tatarstan allowed water sampling to be conducted almost immediately after seismic events. Some regularity in the variation of salt and microelement compositions of water has been outlined. Earthquake frequency has been found to be related to salt and microelement compositions of water. Water samples have shown decreased total dissolved solids content. At the same time, the total iron content decreases and the boron content increases. Peaks of tectonic activity have been found to coincide with increased methane contents. Earthquake peaks have also been found to coincide with maximum hydrogen contents over the whole observation period. A similar relationship has been found for nitrogen Archaean/Proterozoic groundwater monitoring shows changes in total salt, trace-component and gas compositions. These can be related to geological processes of various intensities occurring in the Earth's crust. The total hydrocarbon content of groundwaters has been found to depend on the intensity of geological processes, which indicates the possible entry of additional gas amounts from deconsolidated zones of the crystalline basement into the sedimentary Devonian. It has been established that the most informative indicators of the relationship between groundwater parameters and

  12. Assessment on seasonal variation of groundwater quality of phreatic aquifers - A river basin system

    Digital Repository Service at National Institute of Oceanography (India)

    Laluraj, C.M.; Gopinath, G.

    suspended solids (TDS), fluoride and total iron content will help to identify the quality of ground water. Groundwater contamination can often have serious ill ef- fects on human health. Groundwater with low pH values can cause gastrointestinal disorders... is considered as an important parameter for irrigation and industrial purposes. Total dissolved solids help to identify the potability of groundwater. Total iron content may not have direct effects on human health but is of importance due to aesthetic reasons...

  13. Hydrological control of As concentrations in Bangladesh groundwater

    Science.gov (United States)

    Stute, M.; Zheng, Y.; Schlosser, P.; Horneman, A.; Dhar, R. K.; Datta, S.; Hoque, M. A.; Seddique, A. A.; Shamsudduha, M.; Ahmed, K. M.; van Geen, A.

    2007-09-01

    The elevated arsenic (As) content of groundwater from wells across Bangladesh and several other South Asian countries is estimated to slowly poison at least 100 million people. The heterogeneous distribution of dissolved arsenic in the subsurface complicates understanding of its release from the sediment matrix into the groundwater, as well as the design of mitigation strategies. Using the tritium-helium (3H/3He) groundwater dating technique, we show that there is a linear correlation between groundwater age at depths <20 m and dissolved As concentration, with an average slope of 19 μg L-1 yr-1 (monitoring wells only). We propose that either the kinetics of As mobilization or the removal of As by groundwater flushing is the mechanism underlying this relationship. In either case, the spatial variability of As concentrations in the top 20 m of the shallow aquifers can to a large extent be attributed to groundwater age controlled by the hydrogeological heterogeneity in the local groundwater flow system.

  14. Impact of geochemical stressors on shallow groundwater quality

    Science.gov (United States)

    An, Y.-J.; Kampbell, D.H.; Jeong, S.-W.; Jewell, K.P.; Masoner, J.R.

    2005-01-01

    Groundwater monitoring wells (about 70 wells) were extensively installed in 28 sites surrounding Lake Texoma, located on the border of Oklahoma and Texas, to assess the impact of geochemical stressors to shallow groundwater quality. The monitoring wells were classified into three groups (residential area, agricultural area, and oil field area) depending on their land uses. During a 2-year period from 1999 to 2001 the monitoring wells were sampled every 3 months on a seasonal basis. Water quality assay consisted of 25 parameters including field parameters, nutrients, major ions, and trace elements. Occurrence and level of inorganics in groundwater samples were related to the land use and temporal change. Groundwater of the agricultural area showed lower levels of ferrous iron and nitrate than the residential area. The summer season data revealed more distinct differences in inorganic profiles of the two land use groundwater samples. There is a possible trend that nitrate concentrations in groundwater increased as the proportions of cultivated area increased. Water-soluble ferrous iron occurred primarily in water samples with a low dissolved oxygen concentration and/or a negative redox potential. The presence of brine waste in shallow groundwater was detected by chloride and conductivity in oil field area. Dissolved trace metals and volatile organic carbons were not in a form of concentration to be stressors. This study showed that the quality of shallow ground water could be related to regional geochemical stressors surrounding the lake. ?? 2005 Elsevier B.V. All rights reserved.

  15. Groundwater hydrogeochemical characteristics in rehabilitated coalmine spoils

    Science.gov (United States)

    Gomo, M.; Masemola, E.

    2016-04-01

    The investigation aims to identify and describe hydrogeochemical processes controlling the evolution of groundwater chemistry in rehabilitated coalmine spoils and their overall influence on groundwater quality at a study area located in the Karoo basin of South Africa. A good understanding of the processes that controls the evolution of the mine water quality is vital for the planning, application and management of post-mining remedial actions. The study utilises scatter plots, statistical analysis, PHREEQC hydrogeochemical modelling, stoichiometric reaction ratios analysis, and the expanded Durov diagram as complimentary tools to interpret the groundwater chemistry data collected from monitoring boreholes from 1995 to 2014. Measured pH ranging between 6-8 and arithmetic mean of 7.32 shows that the groundwater system is characterised by circumneutral hydrogeochemical conditions period. Comparison of measured groundwater ion concentrations to theoretical reaction stoichiometry identifies Dolomite-Acid Mine Drainage (AMD) neutralisation as the main hydrogeochemical process controlling the evolution of the groundwater chemistry. Hydrogeochemical modelling shows that, the groundwater has temporal variations of calcite and dolomite saturation indices characterised by alternating cycles of over-saturation and under-saturation that is driven by the release of sulphate, calcium and magnesium ions from the carbonate-AMD neutralization process. Arithmetic mean concentrations of sulphate, calcium and magnesium are in the order of 762 mg/L, 141 mg/L and 108 mg/L. Calcium and magnesium ions contribute to very hard groundwater quality conditions. Classification based on total dissolved solids (TDS), shows the circumneutral water is of poor to unacceptable quality for drinking purposes. Despite its ability to prevent AMD formation and leaching of metals, the dolomite-AMD neutralisation process can still lead to problems of elevated TDS and hardness which mines should be aware of

  16. Temporal evolution of depth-stratified groundwater salinity in municipal wells in the major aquifers in Texas, USA.

    Science.gov (United States)

    Chaudhuri, Sriroop; Ale, Srinivasulu

    2014-02-15

    We assessed spatial distribution of total dissolved solids (TDS) in shallow (150 m) municipal (domestic and public supply) wells in nine major aquifers in Texas for the 1960s-1970s and 1990s-2000s periods using geochemical data obtained from the Texas Water Development Board. For both time periods, the highest median groundwater TDS concentrations in shallow wells were found in the Ogallala and Pecos Valley aquifers and that in the deep wells were found in the Trinity aquifer. In the Ogallala, Pecos Valley, Seymour and Gulf Coast aquifers, >60% of observations from shallow wells exceeded the secondary maximum contaminant level (SMCL) for TDS (500 mg L(-1)) in both time periods. In the Trinity aquifer, 72% of deep water quality observations exceeded the SMCL in the 1990s-2000s as compared to 64% observations in the 1960s-1970s. In the Ogallala, Edwards-Trinity (plateau), and Edwards (Balcones Fault Zone) aquifers, extent of salinization decreased significantly (paquifers), north central (Trinity-downdip aquifer) and south (southern Gulf Coast aquifer) Texas. In west Texas, mixed cation SO4-Cl facies led to groundwater salinization, as compared to Na-Cl facies in the southern Gulf Coast, and Ca-Na-HCO3 and Na-HCO3 facies transitioning to Na-Cl facies in the Trinity-downdip regions. Groundwater mixing ensuing from cross-formational flow, seepage from saline plumes and playas, evaporative enrichment, and irrigation return flow had led to progressive groundwater salinization in west Texas, as compared to ion-exchange processes in the north-central Texas, and seawater intrusion coupled with salt dissolution and irrigation return flow in the southern Gulf Coast regions.

  17. Flourescence Humic Substances in Arsenic Contaminated Groundwater of Bangladesh

    Directory of Open Access Journals (Sweden)

    SHAFI M. TAREQ

    2012-06-01

    Full Text Available In the past, only arsenic (As concentrations in groundwater of Bangladesh were considered as having direct effects on the epidemical degrees of different types of diseases including arsenicosis, but the results of the present investigation indicated that fluorescence humic substance (HS is also an important component of dissolved organic matter in groundwater of Bangladesh. Therefore, it is suspected that both fluorescent HS and As in groundwater may have effects on the biological toxicity. The evidence of presence of high fluorescent HS and As in groundwater of Faridpur supports the above synergistic effect. The spatial distribution of fluorescence HS and As in groundwater of Faridpur indicated that the variations may be related to local hydrogeological conditions.

  18. Groundwater quality and hydrogeological characteristics of Malacca state in Malaysia

    Directory of Open Access Journals (Sweden)

    Shirazi Sharif Moniruzzaman

    2015-03-01

    Full Text Available Groundwater quality and aquifer productivity of Malacca catchment in Peninsular Malaysia are presented in this article. Pumping test data were collected from 210 shallow and 17 deep boreholes to get well inventory information. Data analysis confirmed that the aquifers consisting of schist, sand, limestone and volcanic rocks were the most productive aquifers for groundwater in Malacca state. GIS-based aquifer productivity map was generated based on bedrock and discharge capacity of the aquifers. Aquifer productivity map is classified into three classes, namely high, moderate and low based on discharge capacity. Groundwater potential of the study area is 35, 57 and 8% of low, moderate and high class respectively. Fifty two shallow and 14 deep aquifer groundwater samples were analyzed for water quality. In some cases, groundwater quality analysis indicated that the turbidity, total dissolved solids, iron, chloride and cadmium concentrations exceeded the limit of drinking water quality standards.

  19. Influence of groundwater composition on subsurface iron and arsenic removal

    KAUST Repository

    Moed, David H.

    2012-06-01

    Subsurface arsenic and iron removal (SAR/SIR) is a novel technology to remove arsenic, iron and other groundwater components by using the subsoil. This research project investigated the influence of the groundwater composition on subsurface treatment. In anoxic sand column experiments, with synthetic groundwater and virgin sand, it was found that several dissolved substances in groundwater compete for adsorption sites with arsenic and iron. The presence of 0.01 mmol L -1phosphate, 0.2 mmol L -1 silicate, and 1 mmol L -1 nitrate greatly reduced the efficiency of SAR, illustrating the vulnerability of this technology in diverse geochemical settings. SIR was not as sensitive to other inorganic groundwater compounds, though iron retardation was limited by 1.2 mmol L -1 calcium and 0.06 mmol L -1 manganese. © IWA Publishing 2012.

  20. Polyethylene imine-metal salt solid electrolyte

    Science.gov (United States)

    Davis, G. T.; Chiang, C. K.; Takahashi, T.

    1985-02-01

    This research pertains to the development of new solid battery electrolytes. An object of this invention is to provide polymeric electrolytes using a wider variety of metal salts. These and other objects of this invention are accomplished by providing: (1) a solid polymer electrolyte comprising: a matrix of linear poly(ethylene amine) having the formula (-CH2CH2NH-)n; and (2) a metal salt which is LiI, LiClO4, NaI, NaBr, KI, CsSCN, AgNO3, CuCl1, CoCl2, or Mg(ClO4)2, wherein the salt is dissolved in and distributed throughout the poly(ethylene amine) matrix and from more than zero to 0.10 moles of salt are used per mole of monomer repeat unit, (-CH2CH2NH-).

  1. Influence of irrigation on the level, salinity and flow of groundwater at ...

    African Journals Online (AJOL)

    2010-03-31

    Mar 31, 2010 ... Suitable internal subsurface drainage should be cleaned, ... Keywords: Drainage, irrigation and scheduling, soil water quality, water and salt balance ..... groundwater was pumped or bailed out of the piezometers and.

  2. Geochemical and isotopic characteristics of groundwater from Velenje Basin, Slovenia

    Science.gov (United States)

    Kanduč, Tjaša; Grassa, Fausto; Mori, Nataša; Verbovšek, Timotej

    2016-04-01

    The Velenje Basin in Slovenia is one of the largest actively mined coal basins in central Europe, producing around 4 million tons of lignite per year. Large amounts of groundwater are extracted from aquifers to facilitate underground mining of coal, and coal seam gas outbursts are a serious mine safety concern. This study analyses the geochemical and isotopic composition of groundwater to provide a general understanding of hydrogeological and geochemical processes in groundwater. Thirty-eight groundwater samples were taken from dewatering objects in the mine and at the surface in years 2014-2015. Groundwater in the Triassic aquifer is dominated by hydrogen carbonate, calcium, magnesium and isotopic composition of dissolved inorganic carbon in the range from -19.3 to -2.8‰ indicating degradation of soil organic matter and dissolution of carbonate minerals. In contrast, groundwater in the Pliocene aquifers is enriched in magnesium, sodium, calcium, potassium, and silicon, and has high alkalinity, with isotopic composition of dissolved inorganic carbon in the range of -14.4 to +4.6‰ . Based on isotopic composition of dissolved inorganic carbon values in all aquifers (Pliocene and Triassic), influencing processes are the dissolution of carbonate minerals and dissolution of organic matter, and additionally methanogenesis in the Pliocene aquifers. Based on the Principal Component Analysis (PCA) we can conclude that following different types of groundwater in Velenje Basin could be distinguished based on geochemical and isotopic data: Triassic aquifers with higher pH and lower conductivity and chloride, Pliocene, Pliocene 1 and Pliocene 2 aquifers with lower pH and higher conductivity and chloride contents, and Pliocene 3 and Pliocene 2, 3 aquifers with the highest pH and lowest conductivity and chloride contents. Major dissolved gas component in groundwater are carbon dioxide, nitrogen and methane. Concentrations of dissolved gases dewatering Triassic strata are low

  3. 1997 Comprehensive TNX Area Annual Groundwater and Effectiveness Monitoring Report

    Energy Technology Data Exchange (ETDEWEB)

    Chase, J.

    1998-04-01

    Shallow groundwater beneath the TNX Area at the Savannah River Site (SRS) has been contaminated with chlorinated volatile organic compounds (CVOCs) such as trichloroethylene (TCE) and carbon tetrachloride. In November 1994, an Interim Record of Decision (IROD) was agreed to and signed by the U. S. Department of Energy (DOE), the Environmental Protection Agency (EPA), and the South Carolina Department of Health {ampersand} Environmental Control (SCDHEC). The Interim Record of Decision requires the installation of a hybrid groundwater corrective action (HGCA) to stabilize the plume of groundwater contamination and remove CVOCs dissolved in the groundwater. The hybrid groundwater corrective action included a recovery well network, purge water management facility, air stripper, and an airlift recirculation well. The recirculation well was dropped pursuant to a test that indicated it to be ineffective at the TNX Area. Consequently, the groundwater corrective action was changed from a hybrid to a single action, pump-and-treat approach. The Interim Action (IA) T-1 air stripper system began operation on September 16, 1996. a comprehensive groundwater monitoring program was initiated to measure the effectiveness of the system. As of December 31, 1997, the system has treated 32 million gallons of contaminated groundwater removed 32 pounds of TCE. The recovery well network created a `capture zone` that stabilized the plume of contaminated groundwater.

  4. Potential Antifreeze Compounds in Present-Day Martian Seepage Groundwater

    OpenAIRE

    Jiin-Shuh Jean; Chieh-Hou Yang; Ming-Jer Lee; Ming-Kuo Lee; Ming-Hung Chien

    2008-01-01

    Is the recently found seepage groundwater on Mars pure H2O, or mixed with salts and other antifreeze compounds? Given the surface conditions of Mars, it is unlikely that pure water could either exist in its liquid state or have shaped Mars¡¦ fluid erosional landforms (gullies, channels, and valley networks). More likely is that Mars¡¦ seepage groundwater contains antifreeze and salt compounds that resist freezing and suppress evaporation. This model better accounts for Mars¡¦ enigmatic surfac...

  5. Nitrite toxicity of Litopenaeus vannamei in water containing low concentrations of sea salt or mixed salts

    Science.gov (United States)

    Sowers, A.; Young, S.P.; Isely, J.J.; Browdy, C.L.; Tomasso, J.R.

    2004-01-01

    The uptake, depuration and toxicity of environmental nitrite was characterized in Litopenaeus vannamei exposed in water containing low concentrations of artificial sea salt or mixed salts. In 2 g/L artificial sea salts, nitrite was concentrated in the hemolymph in a dose-dependent and rapid manner (steady-state in about 2 d). When exposed to nitrite in 2 g/L artificial sea salts for 4 d and then moved to a similar environment without added nitrite, complete depuration occurred within a day. Increasing salinity up to 10 g/L decreased uptake of environmental nitrite. Nitrite uptake in environments containing 2 g/L mixed salts (combination of sodium, potassium, calcium and magnesium chlorides) was similar to or lower than rates in 2 g/L artificial sea salt. Toxicity was inversely related to total dissolved salt and chloride concentrations and was highest in 2 g/L artificial sea salt (96-h medial lethal concentration = 8.4 mg/L nitrite-N). Animals that molted during the experiments did not appear to be more susceptible to nitrite than animals that did not molt. The shallow slope of the curve describing the relationship between toxicity and salinity suggests that management of nitrite toxicity in low-salinity shrimp ponds by addition of more salts may not be practical. ?? Copyright by the World Aquaculture Society 2004.

  6. Chemistry of groundwater of Al-Ahsa Oasis eastern region Saudi Arabia and its predictive effects on soil properties.

    Science.gov (United States)

    Al-Zarah, Abdullah I

    2008-02-01

    Saudi Arabia is an arid and the largest country in the middle east with a total land area of 2.253 x 10(6) km2. Recent urban and rural expansion has shown manifold increases in water use in various sectors. Water resources are limited and non-renewable coupled with unpredicted scanty rainfall. In order to meet the rising water needs, evaluation of water quality is important for allocation to various uses. A total of 101 well water samples were collected from Al-Ahsa Oasis. Water samples were analyzed for total salt concentration, pH, Ca, Mg, Na, K, HCO3, Cl, SO4, NO3, F and B contents. Soil Salinity Development (SSD), adjusted sodium adsorption ratio (adj.SAR), adjusted sodium adsorption ratio (adj. R(Na)) and Exchangeable Sodium Percentage (ESP) were calculated. The EC of groundwater ranged between 1.23 and 5.05 dS m(-1). Sodium was the most abundant cation followed by Ca, Mg and K in descending order. Chloride was the most abundant anion followed by SO4 and HCO3 in groundwater of Al-Ahsa Oasis. A significant correlation was found between Na and Cl (R2 = 0.936). Thermodynamics calculation revealed that an appreciable amount of Ca and Mg is associated with Cl and SO4 ions. The SAR and ESP values are within the permissible limits according to Ayers and Westcot, 1985. The NO3 concentration is within safe limits for drinking purpose according to WHO (1998) standards. The Saturation Indices (SI) indicated that groundwater is under-saturated (negative SI) with respect to certain minerals (for example: calcite, dolomite, gypsum, anhydrite, halite, pyrite, fluorite and aragonite) and oversaturated (positive SI) with respect to some other minerals (For example: Goethite, Siderite and hematite). The negative saturation index (SI) reveals that most of minerals are in un-saturated state and will dissolve more Ca and Mg into the soil solution after irrigation. A good relationship exists between Cl and other ions (Na, Ca and Mg) as well as between SO4 and Ca and Mg ion of

  7. DISSOLVED OXYGEN AND METHANE IN WATER BY A GC HEADSPACE EQUILIBRATION TECHNIQUE

    Science.gov (United States)

    An analytical procedure is described for the determination of dissolved oxygen and methane in groundwater samples. The method consists of generating a helium gas headspace in a water filled bottle, and analysis of the headspace by gas chromatography. Other permanent gases such as...

  8. Baseline assessment of groundwater quality in Wayne County, Pennsylvania, 2014

    Science.gov (United States)

    Senior, Lisa A.; Cravotta, III, Charles A.; Sloto, Ronald A.

    2016-06-30

    The Devonian-age Marcellus Shale and the Ordovician-age Utica Shale, geologic formations which have potential for natural gas development, underlie Wayne County and neighboring counties in northeastern Pennsylvania. In 2014, the U.S. Geological Survey, in cooperation with the Wayne Conservation District, conducted a study to assess baseline shallow groundwater quality in bedrock aquifers in Wayne County prior to potential extensive shale-gas development. The 2014 study expanded on previous, more limited studies that included sampling of groundwater from 2 wells in 2011 and 32 wells in 2013 in Wayne County. Eighty-nine water wells were sampled in summer 2014 to provide data on the presence of methane and other aspects of existing groundwater quality throughout the county, including concentrations of inorganic constituents commonly present at low levels in shallow, fresh groundwater but elevated in brines associated with fluids extracted from geologic formations during shale-gas development. Depths of sampled wells ranged from 85 to 1,300 feet (ft) with a median of 291 ft. All of the groundwater samples collected in 2014 were analyzed for bacteria, major ions, nutrients, selected inorganic trace constituents (including metals and other elements), radon-222, gross alpha- and gross beta-particle activity, selected man-made organic compounds (including volatile organic compounds and glycols), dissolved gases (methane, ethane, and propane), and, if sufficient methane was present, the isotopic composition of methane.Results of the 2014 study show that groundwater quality generally met most drinking-water standards, but some well-water samples had one or more constituents or properties, including arsenic, iron, pH, bacteria, and radon-222, that exceeded primary or secondary maximum contaminant levels (MCLs). Arsenic concentrations were higher than the MCL of 10 micrograms per liter (µg/L) in 4 of 89 samples (4.5 percent) with concentrations as high as 20 µg/L; arsenic

  9. Eddy correlation measurements of submarine groundwater discharge

    Science.gov (United States)

    Crusius, J.; Berg, P.; Koopmans, D.J.; Erban, L.

    2008-01-01

    This paper presents a new, non-invasive means of quantifying groundwater discharge into marine waters using an eddy correlation approach. The method takes advantage of the fact that, in virtually all aquatic environments, the dominant mode of vertical transport near the sediment-water interface is turbulent mixing. The technique thus relies on measuring simultaneously the fluctuating vertical velocity using an acoustic Doppler velocimeter and the fluctuating salinity and/or temperature using rapid-response conductivity and/or temperature sensors. The measurements are typically done at a height of 5-15??cm above the sediment surface, at a frequency of 16 to 64??Hz, and for a period of 15 to 60??min. If the groundwater salinity and/or temperature differ from that of the water column, the groundwater specific discharge (cm d- 1) can be quantified from either a heat or salt balance. Groundwater discharge was estimated with this new approach in Salt Pond, a small estuary on Cape Cod (MA, USA). Estimates agreed well with previous estimates of discharge measured using seepage meters and 222Rn as a tracer. The eddy correlation technique has several desirable characteristics: 1) discharge is quantified under in-situ hydrodynamic conditions; 2) salinity and temperature can serve as two semi-independent tracers of discharge; 3) discharge can be quantified at high temporal resolution, and 4) long-term records of discharge may be possible, due to the low power requirements of the instrumentation. ?? 2007 Elsevier B.V. All rights reserved.

  10. QUALITY OF GROUNDWATER AND AQUATIC HUMIC SUBSTANCES FROM MAIN RESERVOIRE OF GROUND WATER No. 333

    Directory of Open Access Journals (Sweden)

    Izabella Pisarek

    2015-11-01

    Full Text Available The conducted research included the estimation of the quality of groundwater from the Main Reservoir of Ground Water No. 333 area in Opole District, Poland. The groundwater in the analyzed region shows high diversity in quality. The main threat for the quality of water in this region is the human household activity. The main pollutants of groundwater are: dissolved phosphorus, nitrate and ammonium. The quality and quantity of dissolved humic substances in groundwater were also investigated. The results showed that the contents of water-extractable organic carbon varied. Presently, the analyzed groundwater is characterized by large differences in dissolved forms of organic carbon. During migration of the soil solution through the soil profile to groundwater, dissolved humic substances undergo qualitative and quantitative changes. Correlation analysis between the quantity of carbon in soil and aquatic humic substances, especially fulvic acids, indicates the possibility of their translocation in soil profiles and their transformation and migration to groundwater. This conclusion can be confirmed by FT-IR-analysis.

  11. Multi-Objective Management of Saltwater Intrusion in Groundwater. Optimization under Uncertainty

    NARCIS (Netherlands)

    Tran, T.M.

    2004-01-01

    Coastal aquifers are very vulnerable to seawater intrusion through, for example, the overdraft of groundwater exploitation or insufficient recharge from upstream. Problems of salt-intrusion into groundwater have become a considerable concern in many countries with coastal areas. There have been a nu

  12. Groundwater recharge: Accurately representing evapotranspiration

    CSIR Research Space (South Africa)

    Bugan, Richard DH

    2011-09-01

    Full Text Available Groundwater recharge is the basis for accurate estimation of groundwater resources, for determining the modes of water allocation and groundwater resource susceptibility to climate change. Accurate estimations of groundwater recharge with models...

  13. Multi-Objective Management of Saltwater Intrusion in Groundwater. Optimization under Uncertainty

    OpenAIRE

    2004-01-01

    Coastal aquifers are very vulnerable to seawater intrusion through, for example, the overdraft of groundwater exploitation or insufficient recharge from upstream. Problems of salt-intrusion into groundwater have become a considerable concern in many countries with coastal areas. There have been a number of studies that have tried to simulate groundwater flow system in regions under threat of saltwater intrusion into coastal aquifers. These aquifer systems are characterized by either a single ...

  14. Characteristics of Salt Affected Soil and Its Amelioration by Trees

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Salt-affected soils extensively distribute on the earth.Although the causes are various,generally speaking salinization occurrence results from the accumulation of free salts to an extent that causes degradation of vegetation and soils.Besides,irrational human practices have increased soil salinity by allowing excess recharging of groundwater to change the natural balance of the water cycle in the landscape. This reduces the suitability to plant growth and increases the potential for other forms of land ...

  15. Effects of acidic recharge on groundwater at the St. Kevin Gulch site, Leadville, Colorado

    Science.gov (United States)

    Paschke, S.S.; Harrison, W.J.; Walton-Day, K.

    2001-01-01

    The acid rock drainage-affected stream of St. Kevin Gulch recharges the Quaternary sand and gravel aquifer of Tennessee Park, near Leadville, Colorado, lowering pH and contributing iron, cadmium, copper, zinc and sulphate to the ground-water system. Dissolved metal mobility is controlled by the seasonal spring runoff as well as oxidation/reduction (redox) reactions in the aquifer. Oxidizing conditions occur in the unconfined portions of the aquifer whilst sulphate-reducing conditions are found down gradient where semi-confined groundwater flow occurs beneath a natural wetland. Iron-reducing conditions occur in the transition from unconfined to semi-confined groundwater flow. Dissolved iron concentrations are low to not detectable in the alluvial fan recharge zone and increase in a down gradient direction. The effects of low-pH, metal-rich recharge are pronounced during low-flow in the fall when there is a defined area of low pH groundwater with elevated concentrations of dissolved zinc, cadmium, copper and sulphate adjacent to St. Kevin Gulch. Dissolved metal and sulphate concentrations in the recharge zone are diluted during spring runoff, although the maximum concentrations of dissolved zinc, cadmium, copper and sulphate occur at selected down gradient locations during high flow. Dissolved zinc, cadmium and copper concentrations are low to not detectable, whereas dissolved iron concentrations are greatest, in groundwater samples from the sulphate-reducing zone. Attenuation of zinc, cadmium and copper beneath the wetland suggests sulphide mineral precipitation is occurring in the semi-confined aquifer, in agreement with previous site investigations and saturation index calculations. Adsorption of dissolved zinc, cadmium and copper onto iron hydroxides is a minor attenuation process due to the low pH of the groundwater system.

  16. Groundwater Managment Districts

    Data.gov (United States)

    Kansas Data Access and Support Center — This dataset outlines the location of the five Groundwater Management Districts in Kansas. GMDs are locally formed and elected boards for regional groundwater...

  17. Speciation of selenium in groundwater: Seasonal variations and redox transformations

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A. Ramesh [Chemical Laboratory, Central Groundwater Board, South Eastern Coastal Region, E1, Rajaji Bhavan, Besant Nagar, Chennai 600 090 (India); Riyazuddin, P., E-mail: riyazdr@yahoo.co.uk [Department of Analytical Chemistry, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu (India)

    2011-08-15

    Highlights: {yields} Selenium(VI) was the predominant species of Se present in groundwater. {yields} Groundwater recharge increased Se mobilization. {yields} Dissolved oxygen and redox potential control the mobilization of soil selenium. {yields} Shallow groundwater is susceptible for more selenium enrichment than deeper ones. - Abstract: Speciation of selenium in groundwater is essential from the viewpoint of toxicity to organisms and biogeochemical cycling. Selenium speciation in groundwater is controlled by aquifer redox conditions, microbial transformations, dissolved oxygen (DO) and other redox couples. A suburban area of Chennai city in India, where improper waste disposal measures have been practiced is selected for this study. Se(IV), Se(VI) and other hydrochemical parameters were monitored in shallow ground water during pre- and post-monsoon seasons for a period of three years. The objective of the study was to investigate the effect of groundwater recharge on selenium speciation. The concentration of Se(IV), and Se(VI) ranged between 0.15-0.43 {mu}g L{sup -1} and 0.16-4.73 {mu}g L{sup -1}, respectively. During post-monsoon period the concentration of Se(IV), and Se(VI) ranged between 0.15-1.25 {mu}g L{sup -1} and 0.58-10.37 {mu}g L{sup -1}, respectively. Se(VI) was the dominant species of selenium during the pre- and post-monsoon periods. During the post-monsoon periods, leaching of selenium from soil was more effective due to the increased oxidizing nature of the groundwater as indicated by the DO and redox potential (Eh) measurements. This finding has important implications on the behavior of selenium in groundwater, and also on the health of people consuming groundwater from seleniferous areas.

  18. The Extent of Denitrification in Long Island Groundwater using MIMS

    Science.gov (United States)

    Young, C.; Hanson, G. N.; Kroeger, K. D.

    2009-12-01

    Long Island drinking water is provided by a sole source aquifer with nitrate levels in some North Shore communities approaching or exceeding the drinking water standard of 10 mgL-1. Previous workers, using mass balance approaches, suggested that the primary source of nitrogen is sewage effluent and observed a 50% deficit of nitrate in Long Island’s groundwater system. We analyzed dissolved N2/Ar ratios in groundwater from wells to determine if groundwater denitrification is the cause of the nitrogen deficit at two locations where septic tanks are used for sewage treatment and the effluent leaches to the groundwater; a suburban community on the north shore of Long Island (Northport, NY) and parkland on a barrier island at the south shore of Long Island (Watch Hill, Fire Island National Seashore). In Northport we found 0 to 20 % of the nitrate in groundwater denitrified with excess N-NO3- concentrations ranging from 0 to 1.5 mgL-1. These samples had concentrations high in dissolved oxygen (DO), 6 to 11 mgL-1, and low in dissolved organic carbon (DOC), 0.4 to 2.8 mgL-1. At Watch Hill nitrogen is primarily retained as ammonium or dissolved organic nitrogen. Where nitrate is formed, we found up to 99% denitrification. Excess N-NO3- ranged from 0 to 8 mgL-1 with concentrations low in DO, 0.3 to 3.4 mgL-1, and high in DOC, 5.3 to 18.4 mgL-1. The vadose zone in the Northport area has an average thickness of 10-100 feet whereas at Watch Hill it is 1 - 2 feet thick. We hypothesize that the vadose zone thickness affects the extent of denitrification by controlling the amount of DOC and DO that reaches the groundwater. A thick vadose zone allows for more extensive interaction of infiltrating sewage effluent with atmospheric oxygen in the vadose zone which oxidizes DOC. In Northport groundwater has high DO, low DOC and essentially no denitrification leaving 2 to 11 mgL-1 N-NO3- remaining. At the Watch Hill site a thin vadose zone below the sewage leach field provides

  19. Changes in groundwater chemistry before two consecutive earthquakes in Iceland

    KAUST Repository

    Skelton, Alasdair

    2014-09-21

    Groundwater chemistry has been observed to change before earthquakes and is proposed as a precursor signal. Such changes include variations in radon count rates1, 2, concentrations of dissolved elements3, 4, 5 and stable isotope ratios4, 5. Changes in seismic wave velocities6, water levels in boreholes7, micro-seismicity8 and shear wave splitting9 are also thought to precede earthquakes. Precursor activity has been attributed to expansion of rock volume7, 10, 11. However, most studies of precursory phenomena lack sufficient data to rule out other explanations unrelated to earthquakes12. For example, reproducibility of a precursor signal has seldom been shown and few precursors have been evaluated statistically. Here we analyse the stable isotope ratios and dissolved element concentrations of groundwater taken from a borehole in northern Iceland between 2008 and 2013. We find that the chemistry of the groundwater changed four to six months before two greater than magnitude 5 earthquakes that occurred in October 2012 and April 2013. Statistical analyses indicate that the changes in groundwater chemistry were associated with the earthquakes. We suggest that the changes were caused by crustal dilation associated with stress build-up before each earthquake, which caused different groundwater components to mix. Although the changes we detect are specific for the site in Iceland, we infer that similar processes may be active elsewhere, and that groundwater chemistry is a promising target for future studies on the predictability of earthquakes.

  20. Hydrogeochemical quality and suitability studies of groundwater in northern Bangladesh.

    Science.gov (United States)

    Islam, M J; Hakim, M A; Hanafi, M M; Juraimi, Abdul Shukor; Aktar, Sharmin; Siddiqa, Aysha; Rahman, A K M Shajedur; Islam, M Atikul; Halim, M A

    2014-07-01

    Agriculture, rapid urbanization and geochemical processes have direct or indirect effects on the chemical composition of groundwater and aquifer geochemistry. Hydro-chemical investigations, which are significant for assessment of water quality, were carried out to study the sources of dissolved ions in groundwater of Dinajpur district, northern Bangladesh. The groundwater samplish were analyzed for physico-chemical properties like pH, electrical conductance, hardness, alkalinity, total dissolved solids and Ca2+, Mg2+, Na+, K+, CO3(2-), HCO3(-), SO4(2-) and Cl- ions, respectively. Based on the analyses, certain parameters like sodium adsorption ratio, soluble sodium percentage, potential salinity, residual sodium carbonate, Kelly's ratio, permeability index and Gibbs ratio were also calculated. The results showed that the groundwater of study area was fresh, slightly acidic (pH 5.3-6.4) and low in TDS (35-275 mg I(-1)). Ground water of the study area was found suitable for irrigation, drinking and domestic purposes, since most of the parameters analyzed were within the WHO recommended values for drinking water. High concentration of NO3- and Cl- was reported in areas with extensive agriculture and rapid urbanization. Ion-exchange, weathering, oxidation and dissolution of minerals were major geochemical processes governing the groundwater evolution in study area. Gibb's diagram showed that all the samples fell in the rock dominance field. Based on evaluation, it is clear that groundwater quality of the study area was suitable for both domestic and irrigation purposes.

  1. Hydrogeochemical Characteristics of Fluorine in Shallow Groundwater of Tongshan Area

    Institute of Scientific and Technical Information of China (English)

    ZHOU Lai; FENG Qi-yan; LI Hou-yao

    2005-01-01

    Tongshan area,a part of the floodplain of the abandoned Huanghe River, is one of the popular endemic fluorosis areas in East China. One of the reasons is high concentration of fluorine in shallow groundwater. Test results of 36 groundwater samples show that fluorine concentration in shallow groundwater is 0.18-6.7 mg/L and 50 % of the samples exceed the Chinese drinking water quality standard. There exists a significant negative correlation in content between Ca2+ and F-. The correlations between fluorine concentration and other cations (for example Na+, K+, Mg2+) are not significant. The content of dissolved fluorine from the flooding sediments of the Huanghe River that varying from 5.6 mg/kg to 15.2 mg/kg plays an important role in forming the high fluorine groundwater. Usually, the dissolved fluorine content in silt is much higher than that in silty clay and clay. According to the geological investigation fluorine content in deep groundwater (over 60 m) is less than 1.0 mg/L and suitable for drinking, so it is an effective measure to prevent endemic fluorosis by extracting deep groundwater in disease areas.

  2. Geochemical evolution of lacustrine brines from variable-scale groundwater circulation

    Science.gov (United States)

    Donovan, Joseph J.; Rose, Arthur W.

    1994-02-01

    Evaporative groundwater-fed lakes in the glaciated North American Great Plains vary widely in chemistry. A contributing cause is chemical variability of source groundwater intercepted by specific lakes, caused in part by differing depths of groundwater circulation. Aqueous chemical characteristics of 61 lakes and 160 groundwater samples were compared for an area where such lakes are common in eastern Montana-western North Dakota. Results indicate that groundwater chemistry varies according to depth in a similar fashion within different aquifers. Lake water evaporation from initial groundwater solutions typical of three depths was geochemically modeled using PHRQPITZ, based on a Pitzer treatment of activities and equilibria. Results show that chemistry of most lake waters in the study area may correspond to that predicted from evaporation of shallow- and intermediate-depth groundwater, but not of deep groundwater as postulated in some previous investigations. Lakes in shallow surface depressions receive water primarily from shallow (local) groundwater flow; lakes located in deep or broad topographic depressions may additionally receive groundwater from deeper circulation. In the field area studied, relative dominance of anions (sulfate vs. carbonate) in brines is a signature for inferred depth of source. Also diagnostic is the suite of brine salts formed (NaSO 4Mg salts for shallow flow; these plus NaCO 3 salts for intermediate depth flow). Such source signatures will vary from area to area according to depth variations in groundwater chemistry and in stratigraphy. Chemical evolution of lake water is a two-stage process, with a groundwater path (influenced by residence time, depth of circulation, aquifer mineralogy, and related factors) and a surface path (influenced by evaporation rates, lake-aquifer hydraulics, and lake geochemical reactions). Groundwater flow patterns may affect the former set of factors, thereby indirectly controlling lake water

  3. Groundwater Quality Assessment Based on Geographical Information System and Groundwater Quality Index

    Directory of Open Access Journals (Sweden)

    Zahra Derakhshan

    2015-06-01

    Full Text Available Iran is located in an arid and semi-arid part of the world. Accordingly, the management of the water resources in the country is a priority. In this regard, determining the quality and pollution of surface water and groundwater is very important, especially in areas where groundwater resources are used for drinking. Groundwater quality index (GQI checks the components of the available water with various quality levels. To assess the quality of drinking groundwater of Yazd-Ardakan plain according to GQI in geographical information system (GIS environment, the electrical conductivity, sodium, calcium, magnesium, chlorine, pH, sodium adsorption ratio, bicarbonate, sulfate, potassium, water hardness, and all substances dissolved in the waters of 80 wells were determined. The samples were obtained from Yazd Regional Water Organization from 2005 to 2014. Using this data, the map components were plotted by Kriging geostatistical method. Then, the map of GQI was prepared after normalizing each map component, switching to a rating map, and extracting the weight of each component from the rating map. Based on the GQI index map, the index point which was 87 in 2005 has increased to 81 in 2014. These maps show a decline in groundwater quality from west to the east region. This decline in groundwater quality is due to the existence of Neogene Organizations in the east and geomorphologic unit of the bare epandage pediment in the west. The map removal and single-parameter sensitivity analysis showed that GQI index in Yazd-Ardakan plain is more sensitive to the components of electrical conductivity (EC, total dissolved solids (TDS, and total hardness (TH. Therefore, these components should be monitored more carefully and repeatedly.

  4. The Measurement of Dissolved Oxygen

    Science.gov (United States)

    Thistlethwayte, D.; And Others

    1974-01-01

    Describes an experiment in environmental chemistry which serves to determine the dissolved oxygen concentration in both fresh and saline water. Applications of the method at the undergraduate and secondary school levels are recommended. (CC)

  5. Transport of road salt contamination in karst aquifers and soils over multiple timescales.

    Science.gov (United States)

    Robinson, Heather K; Hasenmueller, Elizabeth A

    2017-12-15

    Road deicing has caused widespread environmental Na(+) and Cl(-) release for decades, yet the transport and retention of these contaminants in karst aquifers and soils are poorly understood. We examined the transport dynamics of Na(+) and Cl(-) from road salt in shallow groundwater during flooding and over seasonal timescales by intensively monitoring an urban and a rural karst spring over approximately 2 years. Furthermore, we used a 20-year dataset for the rural spring to determine how salt retention affected long-term geochemical trends in the shallow groundwater. Salt transport was governed by hydrologic pathways through karst aquifers: during winter and early spring floods, flow through preferential pathways rapidly transported salty meltwater or stormwater over hours to days, while the remaining salt-contaminated water moved diffusely through the rock matrix on timescales of months to years. Flood hydrograph separations revealed that event water constituted 61.2% of stormflow on average at the urban spring, leading to more extreme variability in salt concentrations during flooding and throughout the year. This variability indicates that baseflow contributions to urban streams overlying karst aquifers with preferential flowpaths are likely less effective at buffering salt concentrations. In contrast, salt concentrations were less variable in the baseflow-dominated rural spring (28.7% event water). Furthermore, salt was episodically released from soils to shallow groundwater throughout the year during first flush events. A Cl(-) mass balance indicates that Cl(-) applied during previous winters persists within the springs' recharge basins for more than a year, raising baseline concentrations as road salt is introduced faster than it can be flushed from the basin. Inter-annual salt retention by soils or slow groundwater movement likely caused significant Cl(-) and specific conductivity (SpC) increases at the rural spring from 1996 to 2016. Accumulation of salt in

  6. MOUTH DISSOLVING TABLET: AN OVERVIEW

    Directory of Open Access Journals (Sweden)

    Kulkarni S. D.

    2011-04-01

    Full Text Available Mouth dissolving Tablets disintegrate and/or dissolve rapidly in the saliva without the need for water. Some tablets are designed to dissolve in saliva extremely fast, within a few seconds, and are true fast-dissolving tablets. Others contain agents to enhance the rate of tablet disintegration in the oral cavity, and are more appropriately termed fast-disintegrating tablets, as they may take up to a minute to completely disintegrate. Mouth or Fast dissolving tablets have been formulated for pediatric, geriatric and bedridden patients and in the many elderly persons will have difficulties in taking conventional oral dosage forms because of hand tremors and dysphagia. The technologies used for manufacturing fast-dissolving tablets are freeze-drying, spray-drying, molding, sublimation, sugar-based excipients, compression, and disintegration addition. As a result of increased life expectancy, the elderly constitute a large portion of the worldwide population today. These people eventually will experience deterioration of their physiological and physical abilities.

  7. Classification management plan of groundwater quality in Taiwan

    Science.gov (United States)

    Chen, Chun Ming; Chen, Yu Ying; Pan, Shih Cheng; Li, Hui Jun; Hsiao, Fang Ke

    2017-04-01

    Taiwan Environmental Protection Administration has been monitoring regional water quality for 14 years. Since the beginning of 2002 till now, there are 453 regional groundwater monitoring wells in ten groundwater subregions in Taiwan, and the monitoring of groundwater quality has been carried out for a long time. Currently, water quality monitoring project has reached 50 items, while the number of water quality monitoring data has reached more than 20,000. In order to use the monitoring data efficiently, this study constructed the localized groundwater quality indicators of Taiwan. This indicator takes into account the different users' point of view, incorporating the Taiwan groundwater pollution monitoring standards (Category II), irrigation water quality standard and drinking water source water quality standard. 50 items of water quality monitoring projects were simplified and classified. The groundwater quality parameters were divided into five items, such as potability for drinking water, salting, external influence, health influences and toxicity hazard. The weight of the five items of groundwater was calculated comprehensively, and the groundwater quality of each monitoring well was evaluated with three grades of good, ordinary, and poor. According to the monitoring results of the groundwater monitoring wells in October to December of 2016, about 70% of groundwater quality in Taiwan is in good to ordinary grades. The areas with poor groundwater quality were mostly distributed in coastal, agriculture and part of the urban areas. The conductivity or ammonia nitrogen concentration was higher in those regions, showing that groundwater may be salinized or affected by external influences. Groundwater quality indicators can clearly show the current comprehensive situation of the groundwater environment in Taiwan and can be used as a tool for groundwater quality classification management. The indicators can coordinate with the Taiwan land planning policy in the

  8. COASTAL SALT MARSH COMMUNITY CHANGE IN NARRAGANSETT BAY IN RESPONSE TO CULTURAL EUTROPHICATION

    Science.gov (United States)

    Coastal salt marshes are susceptible to cultural eutrophication, particularly the over-enrichment of nitrogen, because they are often located where surface water and groundwater discharge into estuaries. In this report, the current areal extent of coastal salt marshes in Narrag...

  9. Osmosis in groundwater: chemical and electrical extensions to Darcy's Law

    NARCIS (Netherlands)

    Bader, S.

    2005-01-01

    In problems of groundwater flow and solute transport in clayey soils subject to salt concentration gradients, chemical and electro-osmosis can be too important to disregard, as is commonly done in geohydrology. In this thesis, we consider the quantification of these couple effects to be able to

  10. Osmosis in groundwater: chemical and electrical extensions to Darcy's Law

    NARCIS (Netherlands)

    Bader, S.

    2005-01-01

    In problems of groundwater flow and solute transport in clayey soils subject to salt concentration gradients, chemical and electro-osmosis can be too important to disregard, as is commonly done in geohydrology. In this thesis, we consider the quantification of these couple effects to be able to simu

  11. Groundwater - surface water interactions in the Ayeyarwady river delta, Myanmar

    Science.gov (United States)

    Miyaoka, K.; Haruyama, S.; Kuzuha, Y.; Kay, T.

    2012-12-01

    Groundwater is widely used as a water resource in the Ayeyarwady River delta. But, Groundwater has some chemical problem in part of the area. To use safety groundwater for health, it is important to make clear the actual conditions of physical and chemical characteristics of groundwater in this delta. Besides, Ayeyarwady River delta has remarkable wet and dry season. Surface water - groundwater interaction is also different in each season, and it is concerned that physical and chemical characteristics of groundwater is affected by the flood and high waves through cyclone or monsoon. So, it is necessary to research a good aquifer distribution for sustainable groundwater resource supply. The purposes of this study are evaluate to seasonal change of groundwater - surface water interactions, and to investigate the more safety aquifer to reduce the healthy risk. Water samples are collected at 49 measurement points of river and groundwater, and are analyzed dissolved major ions and oxygen and hydro-stable isotope compositions. There are some groundwater flow systems and these water qualities are different in each depth. These showed that physical and chemical characteristics of groundwater are closely related to climatological, geomorphogical, geological and land use conditions. At the upper Alluvium, groundwater quality changes to lower concentration in wet season, so Ayeyarwady River water is main recharge water at this layer in the wet season. Besides, in the dry season, water quality is high concentration by artificial activities. Shallower groundwater is affected by land surface conditions such as the river water and land use in this layer. At lower Alluvium, Arakan and Pegu mountains are main recharge area of good water quality aquifers. Oxygen18 value showed a little affected by river water infiltration in the wet season, but keep stable good water quality through the both seasons. In the wet season, the same groundwater exists and water quality changes through

  12. Iowa ground-water quality

    Science.gov (United States)

    Buchmiller, R.C.; Squillace, P.J.; Drustrup, R.D.

    1987-01-01

    The population served by ground-water supplies in Iowa (fig. L4) is estimated to be about 2,392,000, or 82 percent of the total population (U.S. Geological Survey, 1985, p. 211). The population of Iowa is distributed fairly uniformly throughout the State (fig. IB), with 59 percent residing in rural areas or towns of less than 10,000 (U.S. Bureau of the Census, 1982). Surficial aquifers, the Jordan aquifer, and aquifers that form the uppermost bedrock aquifer in a particular area are most commonly used for drinking-water supplies and usually provide ample amounts of good quality water. However, naturally occurring properties or substances such as hardness, dissolved solids, and radioactivity limit the use of water for drinking purposes in some areas of each of the five principal aquifers (fig. 2/4). Median concentrations of nitrate in all aquifers and radium-226 in all aquifers except the Jordan are within the primary drinking-water standards established by the U.S. Environmental Protection Agency (1986a). Median concentrations for dissolved solids in the surficial, Dakota, and Jordan aquifers exceed secondary drinking-water standards established by the U.S. Environmental Protection Agency (1986b).

  13. Immobilization of IFR salt wastes in mortar

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, D.F.; Johnson, T.R.

    1988-01-01

    Portland cement-base mortars are being considered for immobilizing chloride salt wastes produced by the fuel cycles of Integral Fast Reactors (IFR). The IFR is a sodium-cooled fast reactor with metal alloy fuels. It has a close-coupled fuel cycle in which fission products are separated from the actinides in an electrochemical cell operating at 500/degree/C. This cell has a liquid cadmium anode in which the fuels are dissolved and a liquid salt electrolyte. The salt will be a mixture of either lithium, potassium, and sodium chlorides or lithium, calcium, barium, and sodium chlorides. One method being considered for immobilizing the treated nontransuranic salt waste is to disperse the salt in a portland cement-base mortar that will be sealed in corrosion-resistant containers. For this application, the grout must be sufficiently fluid that it can be pumped into canister-molds where it will solidify into a strong, leach-resistant material. The set times must be longer than a few hours to allow sufficient time for processing, and the mortar must reach a reasonable compressive strength (/approximately/7 MPa) within three days to permit handling. Because fission product heating will be high, about 0.6 W/kg for a mortar containing 10% waste salt, the effects of elevated temperatures during curing and storage on mortar properties must be considered.

  14. Statistical assessment of groundwater resources in Washim district (India).

    Science.gov (United States)

    Rajankar, P N; Tambekar, D H; Ramteke, D S; Wate, S R

    2011-01-01

    Groundwater quality of Washim district of Maharashtra (India) was assessed using quality parameters and water quality index (WQI). In this study, the WQI was analyzed by using pH, turbidity, temperature, nitrates, total phosphates, dissolved oxygen, biochemical oxygen demand, total solids, total coliforms and faecal coliforms, respectively for residential and commercial uses. All the parameters were analyzed both in pre-monsoon and post-monsoon seasons to assess the groundwater quality and seasonal variations. The parameters like turbidity, solids and coliforms showed the seasonal variations. The WQI varied from 72 to 88 in pre-monsoon season and 64 to 88 in post-monsoon season. The results indicate that all groundwater samples in the study area have good water quality in pre-monsoon season but in post-monsoon season 9 percent samples indicated the change in water quality from good to medium, which reveals seasonal variation and groundwater quality deterioration.

  15. Salt vulnerability assessment methodology for municipal supply wells

    Science.gov (United States)

    Betts, Andrew; Gharabaghi, Bahram; McBean, Ed; Levison, Jana; Parker, Beth

    2015-12-01

    De-icing agents containing chloride ions used for winter road maintenance have the potential to negatively impact groundwater resources for drinking water supplies. A novel methodology using commonly-available geospatial data (land use, well head protection areas) and public accessible data (salt application rates, hydrometric data) to identify salt vulnerable areas (SVAs) for groundwater wells is developed to prioritize implementation of better management practices for road salt applications. The approach uses simple mass-balance terms to collect chloride input from 3 pathways: surface runoff, shallow interflow and baseflow. A risk score is calculated, which depends on the land use within the respective municipal supply well protection area. Therefore, it is plausible to avoid costly and extensive numerical modeling (which also would bear many assumptions, simplifications and uncertainties). The method is applied to perform a vulnerability assessment on twenty municipal water supply wells in the Grand River watershed, Ontario, Canada. The calculated steady-state groundwater recharge chloride concentration for the supply wells is strongly correlated to the measured transient groundwater chloride concentrations in the case study evaluation, with an R2 = 0.84. The new method provides a simple, robust, and practical method for municipalities to assess the long-term risk of chloride contamination of municipal supply wells due to road salt application.

  16. Use of major ions to evaluate the hydrogeochemistry of groundwater influenced by reclamation and seawater intrusion, West Nile Delta, Egypt.

    Science.gov (United States)

    Salem, Zenhom El-Said; Osman, Osman M

    2017-02-01

    The aim of this research is to evaluate the groundwater geochemistry in western Nile Delta area as an example of an aquifer influenced by reclamation and seawater intrusion. To conduct this study, 63 groundwater samples and one surface water sample from El Nubaria Canal were collected. To estimate the origin of dissolved ions and the geochemical processes influencing this groundwater, integration between land use change, pedological, hydrogeological, hydrogeochemical, and statistical approaches was considered. Results suggest that the groundwater flow regime changed from northeast and southwest directions around El Nubaria canal before 1966 to northern and northeastern directions due to newly constructed channel network. Soil salinity and mineral contents, seepage from irrigation canal, and seawater intrusion are the main factors controlling the groundwater chemistry. Statistically, the groundwater samples were classified into eight groups, one to four for the deep groundwater and five to eight for the shallow groundwater. The deep groundwater is characterized by two groups of chemicals (SO4-HCO3-Mg-Ca-K and Cl-Na), while the shallow groundwater groups of chemicals are Na-Cl-SO4 and K-HCO3-Ca-Mg. Both shallow groundwater and deep groundwater are mostly saturated with respect to carbonate minerals and undersaturated with respect to chloride minerals. Sulfate minerals are above the saturation limit in the shallow groundwater, but in the deep samples, these minerals are under the saturation limit. Ion exchange, carbonate production, mineral precipitation, and seawater intrusion are the geochemical processes governing the groundwater chemistry in the study area.

  17. Impact of catastrophic events on small mountainous rivers: Temporal and spatial variations in suspended- and dissolved-solid fluxes along the Choshui River, central western Taiwan, during typhoon Mindulle, July 2-6, 2004

    Science.gov (United States)

    Milliman, J. D.; Lee, T. Y.; Huang, J. C.; Kao, S. J.

    2017-05-01

    Small mountainous rivers deliver disproportionately large quantities of suspended and dissolved solids to the global ocean, often in response to catastrophic events such as earthquakes or floods. Here we report on the impact of a major flood on the Choshui River, central-western Taiwan, generated by typhoon Mindulle, July 2-6, 2004, five years after the nearby Mw 7.6 Chichi earthquake. Water samples taken at 3-h intervals at three stations along main stem, as well as from two downriver tributaries, allow us to delineate the temporal and spatial variability in concentrations and fluxes of suspended and dissolved constituents within the middle and lower portions of the river in response to this flood. High suspended-sediment concentrations, some as high as 200 g/l, reflected the rapid erosion of landslide scars and debris deposits generated by super-typhoon Herb in 1996 and the 1999 Chichi earthquake. Dissolved-solid and suspended-sediment discharges totaled 0.22 and 70 million tons (mt), 50 mt of which were discharged in just two days. Particulate organic carbon (POC) discharge, most of which was pre-modern in age, was 195,000 t. More than half of the discharged water, POC and dissolved solids came from upriver, whereas about 70% of the suspended sediment and 60% of the dissolved nitrate came from two downriver tributaries, the Chenyoulan and Qingshui rivers. Spatial and temporal differences in the character and discharge of suspended and dissolved solids within and between rivers in the Choshui drainage basin reflect different geologies, landslide histories, the effects of human impact, and the abrupt draining of the Tsaoling landslide lake in the Qingshui basin, as well as the possible shifting of importance of groundwater vs. overland flow. Neither wind-blown pollutants nor sea salts appear to have contributed significantly to dissolved solid character or discharge. Sediment contribution from the landslides in the Chenyoulan basin generated by super-typhoon Herb

  18. Groundwater-Quality Assessment, Pike County, Pennsylvania, 2007

    Science.gov (United States)

    Senior, Lisa A.

    2009-01-01

    constituents introduced by human activities that pose a health risk or otherwise were of concern in groundwater in the county. The analyses included major ions, nutrients, selected trace metals, volatile organic compounds (VOCs), selected organic wastewater compounds, gross alpha-particle and gross beta-particle activity, uranium, and radon-222. Analyses of the 20 samples were primarily for dissolved constituents, but six samples were analyzed for both dissolved and total metals. Results of the 2007 sampling indicated few water-quality problems, although concentrations of some constituents indicated influence of human activities on groundwater. No constituent analyzed exceeded any primary drinking-water standard or maximum contaminant level (MCL) established by the U.S. Environmental Protection Agency. Radon-222 levels were greater than, or equal to, the proposed MCL of 300 picocuries per liter (pCi/L) in water from 15 (75 percent) of the 20 wells. Radon-222 levels did not exceed the alternative MCL of 4,000 pCi/L in any groundwater sample. Radon-222 is naturally occurring, and the greatest concentrations (up to 2,650 pCi/L) were in water samples from wells in members of the Catskill Formation, a fractured-rock aquifer. The dissolved arsenic concentration of 3.9 micrograms per liter (ug/L) in one sample was greater than the health-advisory (HA) level of 2 ug/L but less than the MCL of 10 ug/L. Recommended or secondary maximum contaminant levels (SMCLs) were exceeded for pH, dissolved iron, and dissolved manganese. In six samples analyzed for dissolved and total concentrations of selected metals, total concentrations commonly were much greater than dissolved concentrations of iron, and to a lesser degree, for arsenic, lead, copper, and manganese. Concentrations of iron above the SMCL of 300 ug/L may be more widespread in the county for particulate iron than for dissolved iron. The total arsenic concentration in one of the six samples was greater than the HA level of

  19. Use of geochemical, isotopic, and age tracer data to develop models of groundwater flow: A case study of Gafsa mining basin-Southern Tunisia

    Science.gov (United States)

    Hamed, Younes; Ahmadi, Riadh; Demdoum, Abdeslam; Bouri, Salem; Gargouri, Imed; Ben Dhia, Hamed; Al-Gamal, Samir; Laouar, Rabah; Choura, Abedjabar

    2014-12-01

    Hydro-(major and trace elements: Cd, F and Sr), isotope (18O, 2H, 3H and 13C) geochemistry and radiogenic carbon (14C) of dissolved inorganic carbon (DIC) were used to investigate the sources of groundwater contamination and the hydrodynamic functioning of the multilayer aquifer system in the mining Gafsa basin (Southwestern Tunisia). The groundwater of the study area is subject to intense exploitation to accommodate all the water demands of this arid area. The Gafsa basin contains a multi-layered aquifer with four principal levels: Upper Zebbag (Cenomanian-Turonian), Abiod (Campanien-Maastrichian), Beglia (Miocene) and Segui (Plio-Quaternary) Formations. The hydrogeology of this system is largely affected by tectonics (Gafsa-Tebessa, Sehib, Negrine-Tozeur, Tabeddit and Metlaoui faults…). The groundwater of these aquifers undergoes a significant decline in water level (≈0.5 m y-1), increasing salinity (TDS increase from 400 to 800-6000 mg l-1: generally, TDS increases from the mountainous regions towards the discharge area) due to a long time of aridity, irregular rainfall and overexploitation (irrigation and industrial activities). Groundwater pumped from the semi-confined Complex Terminal (C.T) aquifers (Cretaceous and Mio-Plio-Quaternary: MPQ) and from the confined Continental Intercalaire (C.I) aquifers is an important production factor in irrigated oases agriculture and phosphate washing in Southwestern Tunisia. A rise in the groundwater salinity has been observed as a consequence of increasing abstraction from the aquifer during the last few decades. The salinization phenomena in the region are complex. Several possible causes for salinization exist: (1) the upwelling of saline and "fossil" water from the underlying, confined "C.I" aquifer; (2) as well as the backflow of agricultural drainage water; (3) phosphate and domestic wastewater; (4) brine intrusion from the salt lake (Sebkha/Garaat); (5) evaporate meteoric water dams (El Khangua and El Oude

  20. Online dissolved methane and total dissolved sulfide measurement in sewers.

    Science.gov (United States)

    Liu, Yiwen; Sharma, Keshab R; Fluggen, Markus; O'Halloran, Kelly; Murthy, Sudhir; Yuan, Zhiguo

    2015-01-01

    Recent studies using short-term manual sampling of sewage followed by off-line laboratory gas chromatography (GC) measurement have shown that a substantial amount of dissolved methane is produced in sewer systems. However, only limited data has been acquired to date due to the low frequency and short span of this method, which cannot capture the dynamic variations of in-sewer dissolved methane concentrations. In this study, a newly developed online measuring device was used to monitor dissolved methane concentrations at the end of a rising main sewer network, over two periods of three weeks each, in summer and early winter, respectively. This device uses an online gas-phase methane sensor to measure methane under equilibrium conditions after being stripped from the sewage. The data are then converted to liquid-phase methane concentrations according to Henry's Law. The detection limit and range are suitable for sewer application and can be adjusted by varying the ratio of liquid-to-gas phase volume settings. The measurement presented good linearity (R² > 0.95) during field application, when compared to off-line measurements. The overall data set showed a wide variation in dissolved methane concentration of 5-15 mg/L in summer and 3.5-12 mg/L in winter, resulting in a significant average daily production of 24.6 and 19.0 kg-CH₄/d, respectively, from the network with a daily average sewage flow of 2840 m³/day. The dissolved methane concentration demonstrated a clear diurnal pattern coinciding with flow and sulfide fluctuation, implying a relationship with the wastewater hydraulic retention time (HRT). The total dissolved sulfide (TDS) concentration in sewers can be determined simultaneously with the same principle.

  1. Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes.

    Science.gov (United States)

    Herrera, Christian; Custodio, Emilio; Chong, Guillermo; Lambán, Luis Javier; Riquelme, Rodrigo; Wilke, Hans; Jódar, Jorge; Urrutia, Javier; Urqueta, Harry; Sarmiento, Alvaro; Gamboa, Carolina; Lictevout, Elisabeth

    2016-01-15

    Laguna Tuyajto is a small, shallow saline water lake in the Andean Altiplano of northern Chile. In the eastern side it is fed by springs that discharge groundwater of the nearby volcanic aquifers. The area is arid: rainfall does not exceed 200mm/year in the rainiest parts. The stable isotopic content of spring water shows that the recharge is originated mainly from winter rain, snow melt, and to a lesser extent from some short and intense sporadic rainfall events. Most of the spring water outflowing in the northern side of Laguna Tuyajto is recharged in the Tuyajto volcano. Most of the spring water in the eastern side and groundwater are recharged at higher elevations, in the rims of the nearby endorheic basins of Pampa Colorada and Pampa Las Tecas to the East. The presence of tritium in some deep wells in Pampa Colorada and Pampa Las Tecas indicates recent recharge. Gas emission in recent volcanoes increase the sulfate content of atmospheric deposition and this is reflected in local groundwater. The chemical composition and concentration of spring waters are the result of meteoric water evapo-concentration, water-rock interaction, and mainly the dissolution of old and buried evaporitic deposits. Groundwater flow is mostly shallow due to a low permeability ignimbrite layer of regional extent, which also hinders brine spreading below and around the lake. High deep temperatures near the recent Tuyajto volcano explain the high dissolved silica contents and the δ(18)O shift to heavier values found in some of the spring waters. Laguna Tuyajto is a terminal lake where salts cumulate, mostly halite, but some brine transfer to the Salar de Aguas Calientes-3 cannot be excluded. The hydrogeological behavior of Laguna Tuyajto constitutes a model to understand the functioning of many other similar basins in other areas in the Andean Altiplano.

  2. Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, Christian, E-mail: cherrera@ucn.cl [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Custodio, Emilio [Department of Geo-Engineering, Technical University of Catalonia/Barcelona Tech (UPC), Barcelona (Spain); Chong, Guillermo [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Lambán, Luis Javier [Geological Institute of Spain (IGME), Zaragoza (Spain); Riquelme, Rodrigo; Wilke, Hans [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Jódar, Jorge [Department of Geo-Engineering, Technical University of Catalonia/Barcelona Tech (UPC), Barcelona (Spain); Urrutia, Javier; Urqueta, Harry [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Sarmiento, Alvaro [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); and others

    2016-01-15

    Laguna Tuyajto is a small, shallow saline water lake in the Andean Altiplano of northern Chile. In the eastern side it is fed by springs that discharge groundwater of the nearby volcanic aquifers. The area is arid: rainfall does not exceed 200 mm/year in the rainiest parts. The stable isotopic content of spring water shows that the recharge is originated mainly from winter rain, snow melt, and to a lesser extent from some short and intense sporadic rainfall events. Most of the spring water outflowing in the northern side of Laguna Tuyajto is recharged in the Tuyajto volcano. Most of the spring water in the eastern side and groundwater are recharged at higher elevations, in the rims of the nearby endorheic basins of Pampa Colorada and Pampa Las Tecas to the East. The presence of tritium in some deep wells in Pampa Colorada and Pampa Las Tecas indicates recent recharge. Gas emission in recent volcanoes increase the sulfate content of atmospheric deposition and this is reflected in local groundwater. The chemical composition and concentration of spring waters are the result of meteoric water evapo-concentration, water–rock interaction, and mainly the dissolution of old and buried evaporitic deposits. Groundwater flow is mostly shallow due to a low permeability ignimbrite layer of regional extent, which also hinders brine spreading below and around the lake. High deep temperatures near the recent Tuyajto volcano explain the high dissolved silica contents and the δ{sup 18}O shift to heavier values found in some of the spring waters. Laguna Tuyajto is a terminal lake where salts cumulate, mostly halite, but some brine transfer to the Salar de Aguas Calientes-3 cannot be excluded. The hydrogeological behavior of Laguna Tuyajto constitutes a model to understand the functioning of many other similar basins in other areas in the Andean Altiplano. - Highlights: • Recent volcanism formations play a key role in producing recharge. • Groundwater can flow across local

  3. Transport of dissolved gases through unsaturated porous media

    Science.gov (United States)

    Maryshev, B. S.

    2017-06-01

    The natural porous media (e.g. soil, sand, peat etc.) usually are partially saturated by groundwater. The saturation of soil depends on hydrostatic pressure which is linearly increased with depth. Often some gases (e.g. nitrogen, oxygen, carbon dioxide, methane etc.) are dissolved into the groundwater. The solubility of gases is very small because of that two assumptions is applied: I. The concentration of gas is equal to solubility, II. Solubility depends only on pressure (for isothermal systems). In this way some part of dissolved gas transfers from the solution to the bubble phase. The gas bubbles are immovably trapped in a porous matrix by surface-tension forces and the dominant mechanism of transport of gas mass becomes the diffusion of gas molecules through the liquid. If the value of water content is small then the transport of gas becomes slow and gas accumulates into bubble phase. The presence of bubble phase additionally decreases the water content and slows down the transport. As result the significant mass of gas should be accumulated into the massif of porous media. We derive the transport equations and find the solution which is demonstrated the accumulation of gases. The influence of saturation, porosity and filtration velocity to accumulation process is investigated and discussed.

  4. Groundwater-quality characteristics for the Wyoming Groundwater-Quality Monitoring Network, November 2009 through September 2012

    Science.gov (United States)

    Boughton, Gregory K.

    2014-01-01

    Groundwater samples were collected from 146 shallow (less than or equal to 500 feet deep) wells for the Wyoming Groundwater-Quality Monitoring Network, from November 2009 through September 2012. Groundwater samples were analyzed for physical characteristics, major ions and dissolved solids, trace elements, nutrients and dissolved organic carbon, uranium, stable isotopes of hydrogen and oxygen, volatile organic compounds, and coliform bacteria. Selected samples also were analyzed for gross alpha radioactivity, gross beta radioactivity, radon, tritium, gasoline range organics, diesel range organics, dissolved hydrocarbon gases (methane, ethene, and ethane), and wastewater compounds. Water-quality measurements and concentrations in some samples exceeded numerous U.S. Environmental Protection Agency (EPA) drinking water standards. Physical characteristics and constituents that exceeded EPA Maximum Contaminant Levels (MCLs) in some samples were arsenic, selenium, nitrite, nitrate, gross alpha activity, and uranium. Total coliforms and Escherichia coli in some samples exceeded EPA Maximum Contaminant Level Goals. Measurements of pH and turbidity and concentrations of chloride, sulfate, fluoride, dissolved solids, aluminum, iron, and manganese exceeded EPA Secondary Maximum Contaminant Levels in some samples. Radon concentrations in some samples exceeded the alternative MCL proposed by the EPA. Molybdenum and boron concentrations in some samples exceeded EPA Health Advisory Levels. Water-quality measurements and concentrations also exceeded numerous Wyoming Department of Environmental Quality (WDEQ) groundwater standards. Physical characteristics and constituents that exceeded WDEQ Class I domestic groundwater standards in some samples were measurements of pH and concentrations of chloride, sulfate, dissolved solids, iron, manganese, boron, selenium, nitrite, and nitrate. Measurements of pH and concentrations of chloride, sulfate, dissolved solids, aluminum, iron

  5. Survey of chemical constituents of Tehran's groundwater.

    Science.gov (United States)

    Shariatpanahi, M; Anderson, A C

    1987-12-01

    One hundred and forty wells throughout the City of Tehran and its environs were sampled to determine the chemical quality of the groundwater. Total alkalinity, pH, conductivity, total dissolved solids, hardness and detergent concentrations were determined as well as levels of bicarbonate, calcium, magnesium, sulphate, chloride, sodium, potassium, fluoride, iodide and nitrate. Generally, chemical pollution of the water supplies was low. There were, however, regional elevations in nitrate, chloride and fluoride. Elevated fluoride levels were primarily in the northern regions of the city while high nitrates and chlorides were found primariiy in industrial areas. The health implications of chemical constituents in drinking water are discussed.

  6. Distribution of Land Use to Purify Contaminated Groundwater by Nitrate

    Science.gov (United States)

    Iizumi, Y.; Tanaka, T.; Kinouchi, T.; Tase, N.; Fukami, K.

    2006-12-01

    Groundwater contamination by nitrate results from over-fertilizing and/or inadequate disposal of livestock excreta has been large-scale problem in agricultural area. Because nitrate is primarily transported to streams via ground water flow, explaining actual condition of groundwater is needed to propose an effective measure for the conservation and restoration of sound nitrogen cycle in agricultural river catchments. The purpose of this research was to clarify a triangular relationship between the groundwater quality and flow system, river water quality and land use. The experimental field is located on a slope from Tsukuba tableland to bottomland, which is a part of Nishi- Yata River watershed in Ibaraki Prefecture, Japan. The site area is about 0.0675 square kilometers and the altitude varies from 24 m to 19 m. Land use of tableland, bottomland and intermediate between them are forestland, paddy field and cropland, respectively. Groundwater quality and level were monitored for the year 2004. During the study period significant differences were not observed in groundwater ionic concentrations. Relative high concentrations of dissolved nitrate were detected in cropland (3 - 43 mg/l) and forestland (74 - 179 mg/l). It revealed that there was a purification zone in the paddy field and the area around its 2-4m and denitrification eliminates nitrate-nitrogen. The pressure head converted into hydraulics head, and the groundwater flow were calculated. According to the results, it seems that groundwater flow from tableland to the riverbed through bottomland. It is presumed that groundwater cultivated in cropland with chemical fertilizer pass through the purification zone of nitrate. On the other hand, it is assumed that groundwater containing nitrate originated from inadequate disposal of livestock excreta discharge from forestland does not pass through the depth of this spot. It is suggested that considering flow system of groundwater to manage distribution of land use

  7. DYNAMICS OF AGRICULTURAL GROUNDWATER EXTRACTION

    OpenAIRE

    Hellegers, Petra J.G.J.; Zilberman, David; van Ierland, Ekko C.

    2001-01-01

    Agricultural shallow groundwater extraction can result in desiccation of neighbouring nature reserves and degradation of groundwater quality in the Netherlands, whereas both externalities are often not considered when agricultural groundwater extraction patterns are being determined. A model is developed to study socially optimal agricultural shallow groundwater extraction patterns. It shows the importance of stock size to slow down changes in groundwater quality.

  8. DYNAMICS OF AGRICULTURAL GROUNDWATER EXTRACTION

    OpenAIRE

    Hellegers, Petra J.G.J.; Zilberman, David; van Ierland, Ekko C.

    2001-01-01

    Agricultural shallow groundwater extraction can result in desiccation of neighbouring nature reserves and degradation of groundwater quality in the Netherlands, whereas both externalities are often not considered when agricultural groundwater extraction patterns are being determined. A model is developed to study socially optimal agricultural shallow groundwater extraction patterns. It shows the importance of stock size to slow down changes in groundwater quality.

  9. Geochemical controls on shale groundwaters: Results of reaction path modeling

    Energy Technology Data Exchange (ETDEWEB)

    Von Damm, K.L.; VandenBrook, A.J.

    1989-03-01

    The EQ3NR/EQ6 geochemical modeling code was used to simulate the reaction of several shale mineralogies with different groundwater compositions in order to elucidate changes that may occur in both the groundwater compositions, and rock mineralogies and compositions under conditions which may be encountered in a high-level radioactive waste repository. Shales with primarily illitic or smectitic compositions were the focus of this study. The reactions were run at the ambient temperatures of the groundwaters and to temperatures as high as 250/degree/C, the approximate temperature maximum expected in a repository. All modeling assumed that equilibrium was achieved and treated the rock and water assemblage as a closed system. Graphite was used as a proxy mineral for organic matter in the shales. The results show that the presence of even a very small amount of reducing mineral has a large influence on the redox state of the groundwaters, and that either pyrite or graphite provides essentially the same results, with slight differences in dissolved C, Fe and S concentrations. The thermodynamic data base is inadequate at the present time to fully evaluate the speciation of dissolved carbon, due to the paucity of thermodynamic data for organic compounds. In the illitic cases the groundwaters resulting from interaction at elevated temperatures are acid, while the smectitic cases remain alkaline, although the final equilibrium mineral assemblages are quite similar. 10 refs., 8 figs., 15 tabs.

  10. Hydrogen Peroxide in Groundwater at Rifle, Colorado

    Science.gov (United States)

    Yuan, X.; Nico, P. S.; Williams, K. H.; Hobson, C.; Davis, J. A.

    2015-12-01

    Hydrogen peroxide (H2O2), as a reactive transient presenting ubiquitously in natural surface waters, can react with a large suite of biologically important and redox-sensitive trace elements. The dominant source of H2O2 in natural waters has long been thought to be photo-oxidation of chromophoric dissolved organic matter by molecular oxygen to produce superoxide radical, which then proceeds via dismutation to generate H2O2. However, recent studies have indicated that dark production of H2O2 in deep seawater, principally by biological production, is potentially on par with photochemical generation. Here, we present evidence for abiotic dark generation of H2O2 in groundwater in an alluvial aquifer adjacent to the Colorado River near Rifle, CO. Background H2O2 concentrations were determined in situ using a sensitive chemiluminescence-based method. Our results suggest H2O2 concentrations ranged from lower than the detection limit (1 nM) to 54 nM in different monitoring wells at the site, and the concentrations exhibited close correlations with profiles of dissolved oxygen and iron concentrations in the wells, indicating a possible metal redox cycling mechanism. In addition, dissolved natural organic matter, which could potentially coordinate the interconversion of ferric and ferrous species, might also play an important role in H2O2 formation. While biologically mediated activities have been recognized as the major sink of H2O2, the detected H2O2 pattern in groundwater suggests the existence of a balance between H2O2 source and decay, which potentially involves a cascade of biogeochemically significant processes, including the interconversion of ferrous/ferric species, the generation of more reactive oxygen species, such as hydroxyl radical, the depletion of dissolved oxygen and further transformation of natural organic matter and other chemical pollutants.

  11. Tracing organic matter composition and distribution and its role on arsenic release in shallow Cambodian groundwaters

    Science.gov (United States)

    Lawson, Michael; Polya, David A.; Boyce, Adrian J.; Bryant, Charlotte; Ballentine, Christopher J.

    2016-04-01

    Biogeochemical processes that utilize dissolved organic carbon are widely thought to be responsible for the liberation of arsenic from sediments to shallow groundwater in south and southeast Asia. The accumulation of this known carcinogen to hazardously high concentrations has occurred in the primary source of drinking water in large parts of densely populated countries in this region. Both surface and sedimentary sources of organic matter have been suggested to contribute dissolved organic carbon in these aquifers. However, identification of the source of organic carbon responsible for driving arsenic release remains enigmatic and even controversial. Here, we provide the most extensive interrogation to date of the isotopic signature of ground and surface waters at a known arsenic hotspot in Cambodia. We present tritium and radiocarbon data that demonstrates that recharge through ponds and/or clay windows can transport young, surface derived organic matter into groundwater to depths of 44 m under natural flow conditions. Young organic matter dominates the dissolved organic carbon pool in groundwater that is in close proximity to these surface water sources and we suggest this is likely a regional relationship. In locations distal to surface water contact, dissolved organic carbon represents a mixture of both young surface and older sedimentary derived organic matter. Ground-surface water interaction therefore strongly influences the average dissolved organic carbon age and how this is distributed spatially across the field site. Arsenic mobilization rates appear to be controlled by the age of dissolved organic matter present in these groundwaters. Arsenic concentrations in shallow groundwaters (20 m) groundwaters. We suggest that, while the rate of arsenic release is greatest in shallow aquifer sediments, arsenic release also occurs in deeper aquifer sediments and as such remains an important process in controlling the spatial distribution of arsenic in the

  12. Groundwater sustainability strategies

    Science.gov (United States)

    Gleeson, Tom; VanderSteen, Jonathan; Sophocleous, Marios A.; Taniguchi, Makoto; Alley, William M.; Allen, Diana M.; Zhou, Yangxiao

    2010-01-01

    Groundwater extraction has facilitated significant social development and economic growth, enhanced food security and alleviated drought in many farming regions. But groundwater development has also depressed water tables, degraded ecosystems and led to the deterioration of groundwater quality, as well as to conflict among water users. The effects are not evenly spread. In some areas of India, for example, groundwater depletion has preferentially affected the poor. Importantly, groundwater in some aquifers is renewed slowly, over decades to millennia, and coupled climate–aquifer models predict that the flux and/or timing of recharge to many aquifers will change under future climate scenarios. Here we argue that communities need to set multigenerational goals if groundwater is to be managed sustainably.

  13. Shallow ground-water conditions, Tom Green County, Texas

    Science.gov (United States)

    Lee, J.N.

    1986-01-01

    Most of the water needs of Tom Green County, Texas, are supplied by ground water; however, the city of San Angelo is supplied by surface water. Groundwater withdrawals during 1980 (latest year for which data are available) in Tom Green County totaled about 15,300 acre-feet, all derived from shallow aquifers. Shallow aquifers in this report refer to the ground-water system generally less than 400 feet deep that contains water with less than a 10,000 milligrams per liter concentration of dissolved solids; aquifers comprising this system include: The Leona, Comanche Peak, Trinity, Blaine, San Angelo, Choza, Bullwagon, Vale, Standpipe, and Arroyo aquifers.

  14. A CORRELATION AND REGRESSION STUDY ON THE GROUNDWATER QUALITY IN ALIGARH CITY, UTTAR PRADESH

    Directory of Open Access Journals (Sweden)

    Ummatul Fatima

    2015-07-01

    Full Text Available Ground water is the vital source of sustenance and survival of every living organism. The present study aimed at a statistical regression analysis of Groundwater at 16 locations of Aligarh city, Uttar Pradesh. A correlation study has been carried out amongst all possible pairs of 15 physico-chemical parameters viz., pH, total acidity, phenolphthalein alkalinity, total alkalinity, total hardness, calcium, magnesium, dissolved oxygen, chemical oxygen demand, turbidity, electrical conductivity, total solid, total dissolved solid, total suspended solid and chloride to assess groundwater quality. The correlation analysis provides an excellent tool for the prediction of parameter values within reasonable degree of accuracy. The existence of strong correlation between Total Hardness & Magnesium and Total Dissolved Solid & Total Solid are ascertained. The analysis reveals that the groundwater of the area needs some treatment before consumption and it also needs to be protected from the perils of contamination.

  15. Ground-water quality in Bannock, Bear Lake, Caribou, and part of Power counties, southeastern Idaho

    Science.gov (United States)

    Seitz, H.R.; Norvitch, R.F.

    1979-01-01

    The 103 wells sampled during the study establish a quasi-network that could be resampled in the future to document and analyze changes in ground-water quality in the southeastern Idaho study area. The main aquifers are categorized as alluvium of Quaternary age, basalt of Quaternary and (or) Tertiary age, rocks of the Salt Lake Formation of Tertiary age, and undifferentiated bedrock of pre-Tertiary age. Dissolved solids, hardness, nitrite plus nitrate as nitrogen, and chloride concentrations in the ground waters ranged from 165 to 1,690; 78 to 1,700; 0 to 29; and 1.9 to 360 milligrams per liter, respectively. The areal distributions of these constituents are shown on maps. The range and median values of these same constituents are tabulated by aquifer occurrence. Some of the most mineralized and hardest waters occur in the basalt aquifer near travertine deposits (or terraces), which are composed of calcium carbonate precipitates from mineral springs. For irrigation purposes, all the waters are classified as having low-sodium hazard. Most have medium- to high-salinity hazard. (Woodard-USGS)

  16. A universal salt model based on under-ground precipitation of solid salts due to supercritical water `out-salting'

    Science.gov (United States)

    Rueslåtten, H.; Hovland, M. T.

    2010-12-01

    One of the common characteristics of planets Earth and Mars is that both host water (H2O) and large accumulations of salt. Whereas Earth’s surface-environment can be regarded as ‘water-friendly’ and ‘salt hostile’, the reverse can be said for the surface of Mars. This is because liquid water is stable on Earth, and the atmosphere transports humidity around the globe, whereas on planet Mars, liquid water is unstable, rendering the atmosphere dry and, therefore, ‘salt-friendly’. The riddle as to how the salt accumulated in various locations on those two planets, is one of long-lasting and great debate. The salt accumulations on Earth are traditionally termed ‘evaporites’, meaning that they formed as a consequence of the evaporation of large masses of seawater. How the accumulations on Mars formed is much harder to explain, as an ocean only existed briefly. Although water molecules and OH-groups may exist in abundance in bound form (crystal water, adsorbed water, etc.), the only place where free water is expected to be stable on Mars is within underground faults, fractures, and crevices. Here it likely occurs as brine or in the form of ice. Based on these conditions, a key to understanding the accumulation of large deposits of salt on both planets is linked to how brines behave in the subsurface when pressurized and heated beyond their supercritical point. At depths greater than about 3 km (P>300 bars) water will no longer boil in a steam phase. Rather, it becomes supercritical and will attain the phase of supercritical water vapor (SCRIW) with a specific gravity of typically 0.3 g/cm3. An important characteristic of SCRIW is its inability to dissolve the common sea salts. The salt dissolved in the brines will therefore precipitate as solid particles when brines (seawater on the Earth) move into the supercritical P&T-domain (T>400°C, P>300 bars). Numerical modeling of a hydrothermal system in the Atlantis II Deep of the Red Sea indicates that a

  17. Explosives Dissolved from Unexploded Ordnance

    Science.gov (United States)

    2011-10-01

    moisture content) also result in higher corrosion rates especially if the moisture has high dissolved oxygen content ( Manahan 1994). Corrosion of metal is...R. 1993. Handbook of hydrology. New York: McGraw-Hill, Inc. Manahan , S. 1994. Environmental Chemistry. Boca Raton, FL: Lewis Publishers. McCormick

  18. Dissolving pulp from jute stick.

    Science.gov (United States)

    Matin, Mhafuza; Rahaman, M Mostafizur; Nayeem, Jannatun; Sarkar, Mamon; Jahan, M Sarwar

    2015-01-22

    Jute stick is woody portion of jute plant, which remain as leftover after extracting bast fibre. Presently, it is being used for fencing in the rural area. In this investigation, biorefinery concept was initiated in producing dissolving pulp from jute stick by pre-hydrolysis kraft process. At 170°C for 1h of pre-hydrolysis, 70% of hemicelluloses was dissolved with negligible loss of α-cellulose. At this condition, 75% of dissolved sugars in the pre-hydrolysis liquor were in the oligomeric form. The pre-hydrolysed jute stick was subsequently pulped by kraft process with the variation of active alkali. The pulp yield was 36.2% with kappa number 18.5 at the conditions of 16% active alkali for 2h of cooking at 170°C. Final pulp was produced with 92% α-cellulose and 89% brightness after D0EpD1EpD1 bleaching. The produced dissolving pulp can be used in rayon production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Release of dissolved carbohydrates by

    NARCIS (Netherlands)

    Van Oostende, N.; Moerdijk-Poortvliet, T.C.W.; Boschker, H.T.S.; Vyverman, W.; Sabbe, K.

    2013-01-01

    The coccolithophore Emiliania huxleyi plays a pivotal role in the marine carbon cycle. However, we have only limited understanding of how its life cycle and bacterial interactions affect the production and composition of dissolved extracellular organic carbon and its transfer to the particu

  20. The behaviour of salt and salt caverns

    NARCIS (Netherlands)

    Fokker, P.A.

    1995-01-01

    Salts are mined for both storage and extraction purposes, either via dry or solution mining techniques. For operational, environmental and geological purposes, it is important to understand and predict the in situ behaviour of salt, in particular the creep and strength characteristics. A micro-mecha

  1. A daily salt balance model for stream salinity generation processes following partial clearing from forest to pasture

    Directory of Open Access Journals (Sweden)

    M. A. Bari

    2006-01-01

    Full Text Available We developed a coupled salt and water balance model to represent the stream salinity generation process following land use changes. The conceptual model consists of three main components with five stores: (i Dry, Wet and Subsurface Stores, (ii a saturated Groundwater Store and (iii a transient Stream zone Store. The Dry and Wet Stores represent the salt and water movement in the unsaturated zone and also the near-stream dynamic saturated areas, responsible for the generation of salt flux associated with surface runoff and interflow. The unsaturated Subsurface Store represents the salt bulge and the salt fluxes. The Groundwater Store comes into play when the groundwater level is at or above the stream invert and quantifies the salt fluxes to the Stream zone Store. In the stream zone module, we consider a 'free mixing' between the salt brought about by surface runoff, interflow and groundwater flow. Salt accumulation on the surface due to evaporation and its flushing by initial winter flow is also incorporated in the Stream zone Store. The salt balance model was calibrated sequentially following successful application of the water balance model. Initial salt stores were estimated from measured salt profile data. We incorporated two lumped parameters to represent the complex chemical processes like diffusion-dilution-dispersion and salt fluxes due to preferential flow. The model has performed very well in simulating stream salinity generation processes observed at Ernies and Lemon experimental catchments in south west of Western Australia. The simulated and observed stream salinity and salt loads compare very well throughout the study period with NSE of 0.7 and 0.4 for Ernies and Lemon catchment respectively. The model slightly over predicted annual stream salt load by 6.2% and 6.8%.

  2. Dynamics of Agricultural Groundwater Extraction

    NARCIS (Netherlands)

    Hellegers, P.J.G.J.; Zilberman, D.; Ierland, van E.C.

    2001-01-01

    Agricultural shallow groundwater extraction can result in desiccation of neighbouring nature reserves and degradation of groundwater quality in the Netherlands, whereas both externalities are often not considered when agricultural groundwater extraction patterns are being determined. A model is

  3. Hydro-chemical Survey of Groundwater of Delhi, India

    Directory of Open Access Journals (Sweden)

    Masood Alam

    2009-01-01

    Full Text Available The physicochemical parameters and trace metal contents of water samples from Delhi were assessed. A total of 20 water samples were collected from boring, tube well and hand pump and analyzed for the various physicochemical parameters like pH, conductivity, total dissolved solid, total alkalinity, Ca2+ and Mg2+ hardness, chloride ion, dissolved oxygen, biochemical oxygen demand, sulphate and heavy metal contents like Cu, Cr, Cd, Co, Zn and Ni. The results were compared with BIS standards for drinking water. The quality of water samples under study were within the maximum permissible limits. Therefore, the groundwater samples are fit for human consumption without prior treatment.

  4. Geoelectric resistivity sounding for delineating salt water intrusion in the Abu Zenima area, west Sinai, Egypt

    Science.gov (United States)

    Khalil, Mohamed H.

    2006-09-01

    A direct current (dc) resistivity geoelectric technique is applied in the Abu Zenima area, West Sinai, Egypt to delineate salt water intrusion from the Gulf of Suez and evaluate the quality and some of the petrophysical parameters of the aquifer. Sixteen Schlumberger vertical electrical soundings (VES) with maximum AB/2 = 3000 m are conducted. The interpretation of the one-dimensional (1D) inversion of the acquired resistivity data could map the fresh to slightly brackish aquifer (true resistivity = 52-71 Ω m, thickness = 17-66 m), which floats on denser, more saline, deeper water (<5 Ω m). A number of water samples of the fresh aquifer are analysed to determine the total dissolved solids (TDS) concentrations (ppm). A good agreement is observed between the resistivity boundaries and the borehole data. The mutual relations between the aquifer layering, the direction of the groundwater flow and the hydrogeophysical conditions of the aquifer are investigated. The geoelectric (Dar-Zarrouk) parameters are determined and interpreted in terms of the hydraulic conductivity, transimissivity, clay content, grain size distribution and potentiality of the aquifer. The integration of the results indicates a high potentiality and a relatively good quality of the fresh to slightly brackish aquifer in the north-eastern part of the study area.

  5. Salt attack in parking garage in block of flats

    Science.gov (United States)

    Beran, Pavel; Frankeová, Dita; Pavlík, Zbyšek

    2017-07-01

    In recent years many new block of flats with parking garages placed inside the buildings were constructed. This tendency brings beyond question benefits for residents and also for city planning, but it requires new design and structural approaches and advanced material and construction solutions. The analysis of plaster damage on partition wall in parking garage in one of these buildings is presented in the paper. The damage of studied plaster is caused by the salts which are transported together with snow on cars undercarriage into garage area during winter. The snow melts and water with dissolved salts is transported by the capillary suction from concrete floor into the rendered partition wall. Based on the interior temperature, adsorbed water with dissolved chlorides evaporates and from the over saturated pore solution are formed salt crystals that damages the surface plaster layers. This damage would not occur if the partition wall was correctly isolated from the floor finish layer in the parking garage.

  6. [Effects of reclaimed water recharge on groundwater quality: a review].

    Science.gov (United States)

    Chen, Wei-Ping; Lü, Si-Dan; Wang, Mei-E; Jiao, Wen-Tao

    2013-05-01

    Reclaimed water recharge to groundwater is an effective way to relieve water resource crisis. However, reclaimed water contains some pollutants such as nitrate, heavy metals, and new type contaminants, and thus, there exists definite environmental risk in the reclaimed water recharge to groundwater. To promote the development of reclaimed water recharge to groundwater and the safe use of reclaimed water in China, this paper analyzed the relevant literatures and practical experiences around the world, and summarized the effects of different reclaimed water recharge modes on the groundwater quality. Surface recharge makes the salt and nitrate contents in groundwater increased but the risk of heavy metals pollution be smaller, whereas well recharge can induce the arsenic release from sedimentary aquifers, which needs to be paid more attention to. New type contaminants are the hotspots in current researches, and their real risks are unknown. Pathogens have less pollution risks on groundwater, but some virus with strong activity can have the risks. Some suggestions were put forward to reduce the risks associated with the reclaimed water recharge to groundwater in China.

  7. Increased concentrations of potassium in heartwood of trees in response to groundwater contamination

    Science.gov (United States)

    Vroblesky, D.A.; Yanosky, T.M.; Siegel, F.R.

    1992-01-01

    The wood of tuliptrees (Liriodendron tulipifera L.) growing above groundwater contamination from a hazardous-waste landfill in Maryland contained elevated concentrations of potassium (K). The groundwater contamination also contained elevated concentrations of dissolved K, as well as arsenic (As), cadmium (Cd), chloride (Cl), iron (Fe), manganese (Mn), zinc (Zn), and organic solvents. The dissolved K is derived from disposed smoke munitions. The excess K in the tuliptrees is concentrated in the heartwood, the part of the xylem most depleted in K in trees growing outside of the contamination. These data show that the uptake and translocation of K by tuliptrees can be strongly influenced by the availability of K in groundwater contamination and suggest the utility of this species as an areal indicator of groundwater contamination. ?? 1992 Springer-Verlag New York Inc.

  8. Cooking without salt

    Science.gov (United States)

    DASH diet; High blood pressure - DASH; Hypertension - DASH; Low-salt diet - DASH ... Explore cooking with salt substitutes. Add a splash of lemon and other citrus fruits, or wine, to soups and other dishes. Or use them ...

  9. Potential Antifreeze Compounds in Present-Day Martian Seepage Groundwater

    Directory of Open Access Journals (Sweden)

    Jiin-Shuh Jean

    2008-01-01

    Full Text Available Is the recently found seepage groundwater on Mars pure H2O, or mixed with salts and other antifreeze compounds? Given the surface conditions of Mars, it is unlikely that pure water could either exist in its liquid state or have shaped Mars¡¦ fluid erosional landforms (gullies, channels, and valley networks. More likely is that Mars¡¦ seepage groundwater contains antifreeze and salt compounds that resist freezing and suppress evaporation. This model better accounts for Mars¡¦ enigmatic surface erosion. This paper suggests 17 antifreeze compounds potentially present in Martian seepage groundwater. Given their liquid state and physical properties, triethylene glycol, diethylene glycol, ethylene glycol, and 1,3-propylene glycol are advanced as the most likely candidate compounds. This paper also explores how a mixing of glycol or glycerol with salts in the Martian seepage groundwater may have lowered water¡¦s freezing point and raised its boiling point, with consequences that created fluid gully and channel erosion. Ethylene glycol and related hydrocarbon compounds have been identified in Martian and other interstellar meteorites. We suggest that these compounds and their proportions to water be included for detection in future explorations.

  10. Salt—Water Dynamics in Soils:V.Salt Balance in Soil Profiles

    Institute of Scientific and Technical Information of China (English)

    YOUWEN-RUI; MENGFAN-HUA

    1995-01-01

    Salt balance in simulated soil coulumns was calculated on the basis of a large amount of long term observation data.The results showed that under the climate conditions of semi-arid region of the Huang-Huai-Hai Plain,the soils in the columns were under salt accumulation conditions when the groundwater depth was controlled at less than 2.0m,and under desalinization conditions when at larger than 2.5m.In the soil columns with clay soil and silty loam soil intercalated with a clay layer,the amount of salt accumulated was far less than that in the soil column with silty loam soil throughout the whole profile.Under no irriagtion conditions crop planting may increase groundwater evaporation and hence salt accumulation in soil,making the soil columns under desalinization be under salt accumulation conditions.

  11. Numerical model of halite precipitation in porous sedimentary rocks adjacent to salt diapirs

    Science.gov (United States)

    Li, Shiyuan; Wang, Yan; Zhao, Pengyun

    2017-10-01

    Salt diapirs are commonly seen in the North Sea. Below the Zechstein Group exist possibly overpressured salt-anhydrite formations. One explanation as to the salt precipitation in areas with salt diapirs is that salt cementation is thermally driven and occurs strongly in places adjacent to salt diapirs. This paper assumes that the sealing effect of the cap rock above the salt formations is compromised and overpressured fluids, carrying dissolved minerals such as anhydrite (CaSO4) and salt mineral components (NaCl of halite), flow into the porous sedimentary layers above the salt formations. Additionally, a salt-diapir-like structure is assumed to be at one side of the model. The numerical flow and heat transport simulator SHEMAT-Suite was developed and applied to calculating the concentrations of species, and dissolution and precipitation amounts. Results show that the overpressured salt-anhydrite formations have higher pressure heads and the species elements sodium and chlorite are transported into porous sediment rocks through water influx (saturated brine). Halite can precipitate as brine with sodium and chlorite ions flows to the cooler environment. Salt cementation of reservoir rocks leads to decreasing porosity and permeability near salt domes, and cementation of reservoir formations decreases with growing distance to the salt diapir. The proposed approach in this paper can also be used to evaluate precipitation relevant to scaling problems in geothermal engineering.

  12. Groundwater-dependent ecology of the shoreline of the subtropical Lake St Lucia estuary

    Science.gov (United States)

    Taylor, Ricky; Kelbe, Bruce; Haldorsen, Sylvi; Botha, Greg A.; Wejden, Bente; Været, Lars; Simonsen, Marianne B.

    2006-02-01

    The ecology of the St Lucia estuary in South Africa is of unique international importance. During droughts the estuary experiences high salinities, with values above that of seawater. Ion-poor groundwater flowing into the estuary from prominent sand aquifers along its eastern shoreline forms low-salinity habitats for salt-sensitive biota. During droughts, plants and animals can take refuge in the groundwater discharge zone until the condition in the estuary regains tolerable salinity. Simulations of the groundwater discharge indicate that the flow can persist during droughts over at least a decade, and be of great important for the resilience of the estuary. Anthropogenic activities have reduced the river inflow and made the St Lucia estuary more sensitive to droughts. The groundwater has thereby become increasingly important for the estuary’s ecology. Protection of the groundwater discharge along the shoreline itself and actions to increase the groundwater recharge are therefore important management tasks.

  13. Groundwater Quality Deterioration due to Municipal Solid Waste Dumping Practices

    Science.gov (United States)

    Parameswari, Kaliyaperumal; Karunakaran, Krishnasamy

    2011-07-01

    Groundwater is the major source of drinking water in both urban and rural India. The demand for water has increased over the years and this has led to water scarcity. The scarcity situation, especially in urban areas, is aggravated by the problem of water pollution or contamination by solid waste dumping. In many urban centers in India, the quality of groundwater is getting severely affected because of the widespread pollution, due to the discharge of untreated waste water in water bodies and leachate from the unscientific disposal of solid wastes. It is necessary to realize the importance of groundwater and preserve its quality through careful monitoring and remediation. This study focuses on the magnitude of groundwater pollution due to improper solid waste dumping practices prevailing in the southern part of the Chennai Metropolitan Area. The Perungudi dumpsite, a solid waste dumping site in the periphery of Chennai city, India, has been chosen for this study. The chemical characteristic of solid waste and leachate has been studied, and the groundwater samples from various locations around the dumpsite were collected and analyzed. Samples were analyzed for pH, electrical conductivity, total dissolved solids, chlorides, sulfate, calcium, magnesium, total hardness, sodium, potassium, BOD, and COD. Heavy metals such as lead, iron, and zinc have been analyzed. The study reveals that most of the groundwater samples do not conform to drinking water quality standards. The study also indicates that groundwater remediation techniques and proper groundwater quality monitoring on a regular basis are of utmost importance in the study area. A few in-situ groundwater remediation technologies have been suggested to improve the present water quality.

  14. Organic Carbon Fluxes in a Stressed Groundwater System

    Science.gov (United States)

    Baker, A.; Graham, P. W.; Grbich, N.; Chinu, K.; Yu, D.

    2013-12-01

    Dissolved Organic Carbon (DOC) flux in groundwater is poorly understood: influenced by recharge, extraction and surface processes. We reviewed existing datasets for DOC concentration and flux in Australian groundwater systems. In a temperate, semi-arid, Australian research site we measured variations in DOC content during a series of high intensity extraction and recovery events in the surrounding aquifer and abstracted groundwater. Groundwater was abstracted from a fractured basalt / metasediment aquifer overlain by residual soils and flanked by a Quaternary alluvial channel. Groundwater systems included the fractured rock system interconnected with the alluvial aquifer through a leaky aquitard and a perched aquifer held at the soil bedrock interface. Prior to and throughout the test, groundwater samples were collected from wells within the fractured rock, alluvial aquifer and soil bedrock interface and analysed for DOC. Initial DOC concentrations in the upper aquifer were ~2 mg/L, following pumping concentrations increased 36 mg/L (ave) peaking at 72 mg/L. In the lower aquifer initial TOC concentrations were ~1.6 mg/L, during pumping levels increased to 3.98 mg/L (ave) peaking at 14.32 mg/L. Results indicate the fractured rock aquifers ability to recharge was exceeded during intense pumping periods and a larger component of water was drawn from the upper aquifer. This increased the volume of water being drawn through the soil profile and increased DOC content in abstracted groundwater. Hydrological setting, well construction and pumping regime are likely to affect the concentration of DOC within abstracted groundwater. Further attention to abstracted groundwater as a component in terrestrial DOC fluxes is warranted.

  15. Effects of Total Dissolved Solids on Aquatic Organisms: A Review of Literature and Recommendation for Salmonid Species

    OpenAIRE

    P. K. Weber-Scannell; Duffy, L K; Phyllis K. Weber-Scannell; Duffy, Lawrence K.

    2007-01-01

    Total dissolves solids (TDS) are naturally present in water or are the result of mining or some industrial treatment of water. TDS contain minerals and organic molecules that provide benefits such as nutrients or contaminants such as toxic metals and organic pollutants. Current regulations require the periodic monitoring of TDS, which is a measurement of inorganic salts, organic matter and other dissolved materials in water. Measurements of TDS do not differentiate among ions. The amount of T...

  16. Human health and groundwater

    Science.gov (United States)

    The high quality of most groundwaters, consequent upon the self-purification capacity of subsurface strata, has long been a key factor in human health and wellbeing. More than 50% of the world’s population now rely on groundwater for their supply of drinking water – and in most circumstances a prope...

  17. Groundwater and Distribution Workbook.

    Science.gov (United States)

    Ekman, John E.

    Presented is a student manual designed for the Wisconsin Vocational, Technical and Adult Education Groundwater and Distribution Training Course. This program introduces waterworks operators-in-training to basic skills and knowledge required for the operation of a groundwater distribution waterworks facility. Arranged according to the general order…

  18. The salts of Mars

    Science.gov (United States)

    Clark, B. C.; Van Hart, D. C.

    1981-01-01

    Salt compounds are apparently an important component of the fine-grained regolith on Mars. Salt enrichment may be explained either as a secondary concentration of chemical weathering products or as direct incorporation of planetary released volatiles. Geochemical measurements and chemical relationships constrain the salt species and resultant physicochemical consequences. A likely assemblage is dominated by (Mg,Na)SO4, NaCl, and (Mg,Ca)CO3. Formation of brine in equilibrium with such a salt mixture is unlikely under the temperature and water-vapor restrictions prevalent over most, if not all, of the Martian surface. Acidic conditions, accompanying salt formation, favor the preferential destruction of susceptible igneous minerals.

  19. Groundwater or floodwater? Assessing the pathways of metal exports from a coastal acid sulfate soil catchment.

    Science.gov (United States)

    Santos, Isaac R; de Weys, Jason; Eyre, Bradley D

    2011-11-15

    Daily observations of dissolved aluminum, iron, and manganese in an estuary downstream of a coastal acid sulfate soil (CASS) catchment provided insights into how floods and submarine groundwater discharge drive wetland metal exports. Extremely high Al, Fe, and Mn concentrations (up to 40, 374, and 8 mg L(-1), respectively) were found in shallow acidic groundwaters from the Tuckean Swamp, Australia. Significant correlations between radon (a natural groundwater tracer) and metals in surface waters revealed that metal loads were driven primarily by groundwater discharge. Dissolved Fe, Mn, and Al loads during a 16-day flood triggered by a 213 mm rain event were respectively 80, 35, and 14% of the total surface water exports during the four months of observations. Counter clockwise hysteresis was observed for Fe and Mn in surface waters during the flood due to delayed groundwater inputs. Groundwater-derived Fe fluxes into artificial drains were 1 order of magnitude higher than total surface water exports, which is consistent with the known accumulation of monosulfidic black ooze within the wetland drains. Upscaling the Tuckean catchment export estimates yielded dissolved Fe fluxes from global acid sulfate soil catchments on the same order of magnitude of global river inputs into estuaries.

  20. Dissolved Organic Carbon Dynamics Along Terrestrial-aquatic Flowpaths in a Catchment Dominated by Sandy Soils

    Science.gov (United States)

    Wickland, K.; Walker, J. F.; Hood, K.; Butler, K. D.

    2015-12-01

    Aquatic systems receive significant amounts of terrestrially-derived dissolved organic carbon (DOC) from their watersheds. The amount and nature received depends on terrestrial carbon source strength, processing and losses of carbon during transport, and hydrologic connectivity between terrestrial and aquatic systems. While much research has been done on terrestrial DOC dynamics along terrestrial-aquatic flowpaths, there is still considerable uncertainty in many areas including the importance of different carbon sources, microbial metabolism and sorption of DOC, and processing of carbon in groundwater. Here we investigate DOC dynamics in soils, groundwater, and stream waters at the USGS Water, Energy, and Biogeochemical (WEBB) Program research site in northern Wisconsin. This site is well-suited for studying DOC dynamics as soils are sandy and homogenous with small DOC sorption potential, and previous work has characterized the hydrology of the region in detail. We collected water samples over two years from soil pit lysimeters along a series of hillslope transects, from shallow and deep groundwater wells, and from a first-order stream receiving these waters. We measured DOC concentration, DOC optical properties, and biodegradability of DOC. Combined with historical DOC and companion water chemistry data we characterize DOC generation and loss along the following flowpaths: 1) infiltration through the unsaturated zone to the groundwater table, 2) shallow groundwater flow, and 3) long groundwater flowpaths of different origin (lake-derived vs. terrestrial-derived water).

  1. First flush of dissolved compounds

    DEFF Research Database (Denmark)

    Krebs, P.; Holzer, P.; Huisman, J.L.

    1999-01-01

    In a crude conceptual approach it is commonly assumed that in a combined sewer system the concentration of dissolved compounds is diluted by an increasing flow rate due to rainwater inflow. However, theory of hydraulics suggests that these compounds are influenced by hydrodynamic effects....... It is known that since the wave celerity is higher than the flow velocity of the water, the increase of flow rate induced through rain runoff is recognised earlier at a certain downstream section of the combined sewer than the concentration increase of typical rain-water compounds originating from surface...... wash-off. This description implies that the wave front is formed from the fluid that was present in the sewer before the Bow rare increased, that is the sewage! By means of measurements and numerical simulations, it is shown that this effect may cause a significant impact of dissolved compounds...

  2. Trends in groundwater quality in relation to groundwater age

    NARCIS (Netherlands)

    Visser, A.

    2009-01-01

    Groundwater is a valuable natural resource and as such should be protected from chemical pollution. Because of the long travel times of pollutants through groundwater bodies, early detection of groundwater quality deterioration is necessary to efficiently protect groundwater bodies. The aim of this

  3. Trends in groundwater quality in relation to groundwater age

    NARCIS (Netherlands)

    Visser, A.

    2009-01-01

    Groundwater is a valuable natural resource and as such should be protected from chemical pollution. Because of the long travel times of pollutants through groundwater bodies, early detection of groundwater quality deterioration is necessary to efficiently protect groundwater bodies. The aim of this

  4. Nitrate pollution of groundwater; all right…, but nothing else?

    Science.gov (United States)

    Menció, Anna; Mas-Pla, Josep; Otero, Neus; Regàs, Oriol; Boy-Roura, Mercè; Puig, Roger; Bach, Joan; Domènech, Cristina; Zamorano, Manel; Brusi, David; Folch, Albert

    2016-01-01

    Contamination from agricultural sources and, in particular, nitrate pollution, is one of the main concerns in groundwater management. However, this type of pollution entails the entrance of other substances into the aquifer, as well as it may promote other processes. In this study, we deal with hydrochemical and isotopic analysis of groundwater samples from four distinct zones in Catalonia (NE Spain), which include 5 different aquifer types, to investigate the influence of fertilization on the overall hydrochemical composition of groundwater. Results indicate that intense fertilizer application, causing high nitrate pollution in aquifers, also homogenize the contents of the major dissolved ions (i.e.; Cl(-), SO4(2-), Ca(2+), Na(+), K(+), and Mg(2+)). Thus, when groundwater in igneous and sedimentary aquifers is compared, significant differences are observed under natural conditions for Cl(-), Na(+) and Ca(2+) (with p-values ranging from groundwater hydrochemistry (with R(2) values of 0.490, 0.609 and 0.470, for SO4(2-), Ca(2+) and Cl(-), respectively). Nevertheless, the increasing concentration of specific ions is not only attributed to agricultural pollution, but to their enhancing effect upon the biogeochemical processes that control water-rock interactions. Such results raise awareness that these processes should be evaluated in advance in order to assess an adequate groundwater resources management. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Fluoride, Nitrate, and Dissolved-Solids Concentrations in Ground Waters of Washington

    Science.gov (United States)

    Lum, W. E.; Turney, Gary L.

    1984-01-01

    This study provides basic data on ground-water quality throughout the State. It is intended for uses in planning and management by agencies and individuals who have responsibility for or interest in, public health and welfare. It also provides a basis for directing future studies of ground-water quality toward areas where ground-water quality problems may already exist. The information presented is a compilation of existing data from numerous sources including: the Washington Departments of Ecology and Social and Health Services, the Environmental Protection Agency, as well as many other local, county, state and federal agencies and private corporations. Only data on fluoride, nitrate, and dissolved-solids concentrations in ground water are presented, as these constituents are among those commonly used to determine the suitability of water for drinking or other purposes. They also reflect both natural and man-imposed effects on water quality and are the most readily available water-quality data for the State of Washington. The percentage of wells with fluoride, nitrate, or dissolved-solids concentrations exceeding U.S. Environmental Protection Agency Primary and Secondary Drinking Water Regulations were about 1, about 3, and about 3, respectively. Most high concentrations occurred in widely separated wells. Two exceptions were: high concentrations of nitrate and dissolved solids in wells on the Hanford Department of Energy Facility and high concentrations of nitrate in the lower Yakima River basin. (USGS)

  6. Processes and parameters involved in modeling radionuclide transport from bedded salt repositories. Final report. Technical memorandum

    Energy Technology Data Exchange (ETDEWEB)

    Evenson, D.E.; Prickett, T.A.; Showalter, P.A.

    1979-07-01

    The parameters necessary to model radionuclide transport in salt beds are identified and described. A proposed plan for disposal of the radioactive wastes generated by nuclear power plants is to store waste canisters in repository sites contained in stable salt formations approximately 600 meters below the ground surface. Among the principal radioactive wastes contained in these canisters will be radioactive isotopes of neptunium, americium, uranium, and plutonium along with many highly radioactive fission products. A concern with this form of waste disposal is the possibility of ground-water flow occurring in the salt beds and endangering water supplies and the public health. Specifically, the research investigated the processes involved in the movement of radioactive wastes from the repository site by groundwater flow. Since the radioactive waste canisters also generate heat, temperature is an important factor. Among the processes affecting movement of radioactive wastes from a repository site in a salt bed are thermal conduction, groundwater movement, ion exchange, radioactive decay, dissolution and precipitation of salt, dispersion and diffusion, adsorption, and thermomigration. In addition, structural changes in the salt beds as a result of temperature changes are important. Based upon the half-lives of the radioactive wastes, he period of concern is on the order of a million years. As a result, major geologic phenomena that could affect both the salt bed and groundwater flow in the salt beds was considered. These phenomena include items such as volcanism, faulting, erosion, glaciation, and the impact of meteorites. CDM reviewed all of the critical processes involved in regional groundwater movement of radioactive wastes and identified and described the parameters that must be included to mathematically model their behavior. In addition, CDM briefly reviewed available echniques to measure these parameters.

  7. Process for separating dissolved solids from a liquid using an anti-solvent and multiple effect evaporators

    Science.gov (United States)

    Daniels, Edward J.; Jody, Bassam J.; Bonsignore, Patrick V.

    1994-01-01

    A process and system for treating aluminum salt cake containing water soluble halide salts by contacting the salt cake with water to dissolve water soluble halide salts forming a saturated brine solution. Transporting a portion of about 25% of the saturated brine solution to a reactor and introducing into the saturated brine solution at least an equal volume of a water-miscible low-boiling organic material such as acetone to precipitate a portion of the dissolved halide salts forming a three-phase mixture of an aqueous-organic-salt solution phase and a precipitated salt phase and an organic rich phase. The precipitated salt phase is separated from the other phases and the organic rich phase is recycled to the reactor. The remainder of the saturated brine solution is sent to a multiple effect evaporator having a plurality of stages with the last stage thereof producing low grade steam which is used to boil off the organic portion of the solution which is recycled.

  8. Abacus for the determination of the groundwater evaporation in arid areas. Case of the region of Ouargla-Algeria

    Science.gov (United States)

    El Fergougui, Myriam Marie; Boutoutaou, Djamel

    2016-07-01

    One of the possible remedies to control the inputs of salts toward the surface would be by diminishing the groundwater; because areas set on values in arid zones of the region of Ouargla are based upon excessively mineralized groundwater whose level is near the ground surface (0 to 1.5 m). The improvement and stabilization of yields of any cultural practices in these areas can only take place if the salty groundwater is maintained (drained) to a depth of 1.6m. The results of work carried on the determination of the groundwater evaporation in Ouargla show that the evaporation essentially depends on: The climate that reigns above the ground of the groundwater situated on the band from 0 to 0.6 m. The climate and soil texture according the groundwater located in the layer from 0.6 to 1.6 m. The depth of the groundwater when this latter is located beyond 1.6 m.

  9. Dating base flow in streams using dissolved gases and diurnal temperature changes

    Science.gov (United States)

    Sanford, Ward E.; Casile, Gerolamo C.; Haase, Karl B.

    2015-01-01

    A method is presented for using dissolved CFCs or SF6 to estimate the apparent age of stream base flow by indirectly estimating the mean concentration of the tracer in the inflowing groundwater. The mean value is estimated simultaneously with the mean residence times of the gas and water in the stream by sampling the stream for one or both age tracers, along with dissolved nitrogen and argon at a single location over a period of approximately 12–14 h. The data are fitted to an equation representing the temporal in-stream gas exchange as it responds to the diurnal temperature fluctuation. The efficacy of the method is demonstrated by collecting and analyzing samples at six different stream locations across parts of northern Virginia, USA. The studied streams drain watersheds with areas of between 2 and 122 km2 during periods when the diurnal stream temperature ranged between 2 and 5°C. The method has the advantage of estimating the mean groundwater residence time of discharge from the watershed to the stream without the need for the collection of groundwater infiltrating to streambeds or local groundwater sampled from shallow observation wells near the stream.

  10. Contributions of groundwater conditions to soil and water salinization

    Science.gov (United States)

    Salama, Ramsis B.; Otto, Claus J.; Fitzpatrick, Robert W.

    Salinization is the process whereby the concentration of dissolved salts in water and soil is increased due to natural or human-induced processes. Water is lost through one or any combination of four main mechanisms: evaporation, evapotranspiration, hydrolysis, and leakage between aquifers. Salinity increases from catchment divides to the valley floors and in the direction of groundwater flow. Salinization is explained by two main chemical models developed by the authors: weathering and deposition. These models are in agreement with the weathering and depositional geological processes that have formed soils and overburden in the catchments. Five soil-change processes in arid and semi-arid climates are associated with waterlogging and water. In all represented cases, groundwater is the main geological agent for transmitting, accumulating, and discharging salt. At a small catchment scale in South and Western Australia, water is lost through evapotranspiration and hydrolysis. Saline groundwater flows along the beds of the streams and is accumulated in paleochannels, which act as a salt repository, and finally discharges in lakes, where most of the saline groundwater is concentrated. In the hummocky terrains of the Northern Great Plains Region, Canada and USA, the localized recharge and discharge scenarios cause salinization to occur mainly in depressions, in conjunction with the formation of saline soils and seepages. On a regional scale within closed basins, this process can create playas or saline lakes. In the continental aquifers of the rift basins of Sudan, salinity increases along the groundwater flow path and forms a saline zone at the distal end. The saline zone in each rift forms a closed ridge, which coincides with the closed trough of the groundwater-level map. The saline body or bodies were formed by evaporation coupled with alkaline-earth carbonate precipitation and dissolution of capillary salts. Résumé La salinisation est le processus par lequel la

  11. Global depletion of groundwater resources

    NARCIS (Netherlands)

    Wada, Y.; Beek, L.P.H. van; van Kempen, C.M.; Reckman, J.W.T.M.; Vasak, S.; Bierkens, M.F.P.

    2010-01-01

    In regions with frequent water stress and large aquifer systems groundwater is often used as an additional water source. If groundwater abstraction exceeds the natural groundwater recharge for extensive areas and long times, overexploitation or persistent groundwater depletion occurs. Here we provid

  12. Dissolved Mn Speciation and Ligand Characteristics in a Coastal Waterway

    Science.gov (United States)

    Oldham, V.; Jensen, L.; Luther, G. W., III

    2014-12-01

    Soluble manganese speciation (Mn(II) and Mn(III); 0.2 μm filtered) was measured along a salinity gradient in the Broadkill River, a coastal waterway bordered by wetlands and salt marshes in Delaware. We modified an established method of porphyrin (T-4(CP)P) addition, by incorporating a heating step and coupling a 100-cm cell to a UV/Vis detector, to achieve a 4.0 nM sample DL. Surface waters were collected from June to August, 2014 and total dissolved Mn (0.23 - 1.92 μM) first increased then decreased along the salinity gradient (31 ppt to freshwater). However, Mn speciation was highly variable; Mn(III) made up 0-49 % of the total dissolved Mn, where the highest Mn(III) values occurred at sites with high salt-marsh runoff. Mn(III) was not recoverable without the addition of a strong reducing agent, indicating that little or no weak ligand was present, and that a strong ligand was responsible for complexing Mn(III). An assessment of potential strong ligand character was made by precipitating humic matter, by acidifying subsamples to pHyellow color. Upon the addition of 500 μM desferrioxamine-B (DFOB) to the same sample, a peak at 310 nm appeared, indicating the formation of Mn(III)-DFOB. In acidified samples, the Mn(III)-pyrophosphate peak did not change. Humic matter, therefore, may be acting as an Mn(III) binding ligand, outcompeting pyrophosphate for Mn(III), however this natural ligand is outcompeted by a large excess of DFOB. The humic matter and increased Mn likely come from the salt marsh runoff during tidal exchange, and we observed that as salinity increased, the amount of humic binding decreased. These results present the first Mn speciation measurements along a salinity gradient in oxygenated waters.

  13. Tank 29 salt removal method using slurry pump agitation

    Energy Technology Data Exchange (ETDEWEB)

    Parish, W.R.

    1993-11-30

    This report outlines a plan for removing salt from Tank 29. The plan is based, in part, upon the experience gained in the removal of salt from Tank 19 and sludge from Tank 16. Tank 19 was the first tank in which slurry pumps were used during salt dissolution. Salt in Tank 29 will be dissolved to form a nearly saturated salt solution. The goal of Waste Removal is to remove the salt from the tank and deliver it to In-Tank Precipitation (ITP) at a concentration greater than 6.7 molar Na{sup +} (including dilution from transfer steam) to meet ITP requirements. (The amount of wash water used in ITP will be enough to dilute 6.7 molar Na{sup +} salt solution to 5 molar Na{sup +} required for the precipitation step). The solution will be sent to (ITP) for precipitation of soluble cesium and strontium (radioactive elements). The precipitate will be transferred to the Defense Waste Processing Facility (DWPF) for final disposal. A USQD (Unreviewed Safety Question Determination) for criticality safety issue resolution will be completed prior to salt removal.

  14. Ground-water data for the Riley and Andrews Resource Areas, southeastern Oregon

    Science.gov (United States)

    Townley, Paul J.; Soja, Constance M.; Sidle, W.C.

    1980-01-01

    Appraisals of the resources of selected management areas in eastern Oregon are being made by the U.S. Bureau of Land Mangement. To provide needed hydrologic information, the Bureau of Land Management requested the U.S. Geological Survey to inventory ground-water data for the Riley and Andrews Resource Areas. The inventory included field location of selected wells and springs; measurement of ground-water levels, temperatures, specific conductance, and pH; and the collection of ground-water samples from selected sources to determine dissolved chemical constituents.

  15. Groundwater flow system in the valley of Toluca, Mexico: an assay of natural radionuclide specific activities.

    Science.gov (United States)

    Segovia, N; Tamez, E; Peña, P; Carrillo, J; Acosta, E; Armienta, M A; Iturbe, J L

    1999-03-01

    Natural radionuclides and physicochemical parameters have been evaluated in groundwater samples from boreholes belonging to the drinking water supply system of the Toluca City, Mexico. The results obtained for radon and radium, together with the physicochemical parameters of the studied samples, indicate a fast and efficient recharge pattern. The presence of a local and a regional groundwater flows was also observed. The local flow belongs to shallower water, recognized by its low radon content and dissolved ions, as compared with the regional, deeper groundwater flow with a longer residence time.

  16. Groundwater data network interoperability

    Science.gov (United States)

    Brodaric, Boyan; Booth, Nathaniel; Boisvert, Eric; Lucido, Jessica M.

    2016-01-01

    Water data networks are increasingly being integrated to answer complex scientific questions that often span large geographical areas and cross political borders. Data heterogeneity is a major obstacle that impedes interoperability within and between such networks. It is resolved here for groundwater data at five levels of interoperability, within a Spatial Data Infrastructure architecture. The result is a pair of distinct national groundwater data networks for the United States and Canada, and a combined data network in which they are interoperable. This combined data network enables, for the first time, transparent public access to harmonized groundwater data from both sides of the shared international border.

  17. Groundwater contamination in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Tase, Norio [Univ. of Tsukuba, Ibaraki (Japan)

    1992-07-01

    Problems on groundwater contamination in Japan are briefly summarized in this paper. Although normal physical conditions in Japan restrict the possibilities of groundwater contamination, human activities are threatening groundwater resources. A survey by the Environment Agency of Japan showed nationwide spreading of organic substances, such as trichloroethylene as well as nitrogen compounds. Synthetic detergents have also been detected even in rural areas and in deep confined aquifers, although their concentrations are not as high. Public awareness of agrichemical or pesticides abuse, especially from golf courses, is apparent. Other problems such as nitrate-nitrogen, leachate from landfills, and the leaking of underground storage tanks are also discussed. 9 refs., 3 figs., 4 tabs.

  18. Groundwater contamination in Japan

    Science.gov (United States)

    Tase, Norio

    1992-07-01

    Problems on groundwater contamination in Japan are briefly summarized in this paper. Although normal physical conditions in Japan restrict the possibilities of groundwater contamination, human activities are threatening groundwater resources. A survey by the Environment Agency of Japan showed nationwide spreading of organic substances, such as trichloroethylene as well as nitrogen compounds. Synthetic detergents have also been detected even in rural areas and in deep confined aquifers, although their concentrations are not as high. Public awareness of agrichemical or pesticides abuse, especially from golf courses, is apparent. Other problems such as nitrate-nitrogen, leachate from landfills, and the leaking of underground storage tanks are also discussed.

  19. Volatile selenium flux from the great Salt Lake, Utah

    Science.gov (United States)

    Diaz, X.; Johnson, W.P.; Oliver, W.A.; Naftz, D.L.

    2009-01-01

    The removal mechanisms that govern Se concentrations in the Great Salt Lake are unknown despite this terminal lake being an avian habitat of hemispheric importance. However, the volatilization flux of Se from the Great Salt Lake has not been previously measured due to challenges of analysis in this hypersaline environment This paper presents results from recent field studies examining the spatial distribution of dissolved volatile Se (areally and with depth) in the south arm (main body) of the Great Salt Lake. The analyses involved collection of dissolved volatile Se in a cryofocusing trap system via sparging with helium. The cryotrapped volatile Se was digested with nitric acid and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Results show concentrations of dissolved volatile Se that increase with depth in the shallow brine, suggesting that phytoplankton in the open waters and bioherms in shallow sites (transport models corrected to simulate the highly saline environment of the south arm of the Great Salt Lake. The estimated annual flux of volatile Se was 1455 kg/year within a range from 560 to 3780 kg Se/year for the 95% confidence interval and from 970 to 2180 kg Se/year within the 68% confidence interval. ?? 2009 American Chemical Society.

  20. Identification and Evolution of Groundwater Chemistry in the Ejin Sub-Basin of the Heihe River, Northwest China

    Institute of Scientific and Technical Information of China (English)

    SU Yong-Hong; FENG Qi; ZHU Gao-Feng; SI Jian-Hua; ZHANG Yan-Wu

    2007-01-01

    Hydro-chemical characteristics of groundwater and their changes as affected by human activities were studied in the Ejin Sub-Basin of the Inner Mongolia Autonomous Region, China, to understand the groundwater evolution, to identify the predominant geochemical processes taking place along the horizontal groundwater flow path, and to characterize anthropogenic factors affecting the groundwater environment based on previous data. The concentrations of major ions and total dissolved solids (TDS) in the groundwater showed a great variation, with 62.5% of the samples being brackish (TDS ≥ 1000 mg L-1). The groundwater system showed a gradual hydro-chemical zonation composed of Na+-HCO-3, Na+-Mg2+-SO2-4Cl-, and Na+-Cl-. The relationships among the dissolved species allowed identification of the origin of solutes and the processes that generated the observed water compositions. The dissolution of halite, dolomite, and gypsum explained, in part, the presence of Na+, K+, Cl-, SO2-4, and Ca2+, but other processes, such as mixing, Na+ exchange for Ca2+ and Mg2+, and calcite precipitation also contributed to the composition of water. Human activity, in particular large-scale water resources development associated with dramatic population growth in the last 50 years, has led to tremendous changes in the groundwater regime, which reflected in surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality. Solving these largely anthropogenic problems requires concerted, massive and long-term efforts.

  1. Molecular signature of organic nitrogen in septic-impacted groundwater

    Science.gov (United States)

    Arnold, William A.; Longnecker, Krista; Kroeger, Kevin D.; Kujawinski, Elizabeth B.

    2014-01-01

    Dissolved inorganic and organic nitrogen levels are elevated in aquatic systems due to anthropogenic activities. Dissolved organic nitrogen (DON) arises from various sources, and its impact could be more clearly constrained if specific sources were identified and if the molecular-level composition of DON were better understood. In this work, the pharmaceutical carbamazepine was used to identify septic-impacted groundwater in a coastal watershed. Using ultrahigh resolution mass spectrometry data, the nitrogen-containing features of the dissolved organic matter in septic-impacted and non-impacted samples were compared. The septic-impacted groundwater samples have a larger abundance of nitrogen-containing formulas. Impacted samples have additional DON features in the regions ascribed as ‘protein-like’ and ‘lipid-like’ in van Krevelen space and have more intense nitrogen-containing features in a specific region of a carbon versus mass plot. These features are potential indicators of dissolved organic nitrogen arising from septic effluents, and this work suggests that ultrahigh resolution mass spectrometry is a valuable tool to identify and characterize sources of DON.

  2. PFAS - A threat for groundwater and drinking water supply in Sweden?

    Science.gov (United States)

    Lewis, Jeffrey; Banzhaf, Stefan; Ahlkrona, Malva; Arnheimer, Berit; Barthel, Roland; Bergvall, Martin; Blomquist, Niklas; Jacks, Gunnar; Jansson, Cecilia; Lissel, Patrik; Marklund, Lars; Olofsson, Bo; Persson, Kenneth M.; Sjöström, Jan; Sparrenbom, Charlotte

    2015-04-01

    Perfluoroalkyl substances (PFAS) are a group of anthropogenic environmental pollutants that are widely distributed in the global environment. They have multiple industrial uses, including water repellents in clothing, paper coatings and firefighting foam. According to a study released by the Environmental Directorate of the OECD, they are persistent, bioaccumulative and toxic to mammalian species (OECD, 2002). In some municipal drinking water wells in Sweden, measured concentrations of PFAS found to be several hundred times higher than the allowed threshold values. This has created a huge public concern and has recently attracted much media attention in Sweden (e.g. Afzelius et al., 2014; Bergman et al., 2014; Lewis et al., 2014). PFAS findings raised questions such as "What can we do to solve the problem?" When it comes to drinking water, there are a number of techniques that can ensure that PFAS levels are reduced to acceptable levels. This may be a costly challenge, but from a technical point of view it is possible. To ensure the safety of drinking water from a public health perspective is obviously a top priority. However, international experience shows that the cost of cleaning up PFAS in groundwater may be significantly higher than continuously treat drinking water in water works. Approximately fifty percent of Sweden's drinking water comes from groundwater. As a result, there are several ongoing and planned PFAS-related environmental and drinking-water investigations in Sweden. Many aquifers that supply municipal water plants are located in areas of sand and gravel deposits. Such soils have relatively high permeabilities, which permits extraction of large volumes of water. However, the downside to high permeabilities is that they also allow dissolved contaminants as PFAS to spread over large areas. If one disregards the health risks linked to its presence in drinking water, PFAS have an impact on three of Sweden's national environmental quality objectives

  3. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  4. Overview of groundwater management approaches at salinisation risk

    Science.gov (United States)

    Polemio, Maurizio; Zuffianò, Livia Emanuela

    2013-04-01

    All natural waters contain dissolved minerals from interactions with atmospheric and soil gases, mixing with other solutions, and/or interactions with the biosphere and lithosphere. In many cases, these processes result in natural waters containing solute or salinity above concentrations recommended for a specified use, which creates significant social and economic problems. Groundwater salinisation can be caused by natural phenomena and anthropogenic activities. For the former case, we can distinguish terrestrial and marine phenomena. Approximately 16% of the total area of continental earth is potentially involved in groundwater salinisation. Seawater intrusion can be considered to be the primary phenomenon to be studied in terms of groundwater salinisation. Three schematic approaches to the protection of groundwater via salinisation mitigation and/or groundwater salinity improvement are described based on the classifications of the primary salinisation sources and focusing on the effect of seawater intrusion. The complexity of these approaches generally increases due to difficulties caused by groundwater quality and quantity degradation and increased demand for quality water. In order from the lowest to the highest complexity, these approaches are the engineering approach, the discharge management approach, and the water and land management approach. The engineering approach is realised on the local or detailed scale with the purpose of controlling the salinisation, optimising the well discharge with specific technical solutions and/or completing works to improve the quality and/or quantity of the discharged fresh groundwater. The discharge management approach encompasses at least an entire coastal aquifer and defines rules concerning groundwater utilisation and well discharge. The water and land management approach should be applied on the regional scale. Briefly, this approach becomes necessary when one or more need creates an overall framework of high

  5. Fresh groundwater resources in a large sand replenishment

    Science.gov (United States)

    Huizer, Sebastian; Oude Essink, Gualbert H. P.; Bierkens, Marc F. P.

    2016-08-01

    The anticipation of sea-level rise and increases in extreme weather conditions has led to the initiation of an innovative coastal management project called the Sand Engine. In this pilot project a large volume of sand (21.5 million m3) - also called sand replenishment or nourishment - was placed on the Dutch coast. The intention is that the sand is redistributed by wind, current, and tide, reinforcing local coastal defence structures and leading to a unique, dynamic environment. In this study we investigated the potential effect of the long-term morphological evolution of the large sand replenishment and climate change on fresh groundwater resources. The potential effects on the local groundwater system were quantified with a calibrated three-dimensional (3-D) groundwater model, in which both variable-density groundwater flow and salt transport were simulated. Model simulations showed that the long-term morphological evolution of the Sand Engine results in a substantial growth of fresh groundwater resources, in all adopted climate change scenarios. Thus, the application of a local sand replenishment could provide coastal areas the opportunity to combine coastal protection with an increase of the local fresh groundwater availability.

  6. Regional distribution of microbes in groundwater from Haestholmen, Kivetty, Olkiluoto and Romuvaara, Finland

    Energy Technology Data Exchange (ETDEWEB)

    Haveman, S.A.; Nilsson, E.L.; Pedersen, K. [Goeteborg University (Sweden)

    2000-06-01

    Groundwater was sampled with the PAVE groundwater sampling system from eight boreholes at Haestholmen, Kivetty, Olkiluoto and Romuvaara, Finland, in 1998 and 1999, for investigation of microbial populations. The groundwater samples had a wide range of salinity and chemistry and contained 104-105 cells per ml, which is typical for subsurface groundwater. In preparing culture media, two approaches were used and compared. Natural, groundwater-based media were prepared from groundwater from the same section of each borehole tested, and synthetic media were prepared based on groundwater chemistry data. No significant difference was observed between the two types of media for brackish and saline groundwater. The groundwater to a depth of 750 m contained mainly sulphate-reducing bacteria (SRB), ironreducing bacteria (IRB) and heterotrophic acetogenic (HA) bacteria. Autotrophic acetogenic (AA) bacteria and methanogenic archaea were found in some samples. Iron-reducing and HA bacteria predominated in brackish groundwater from Haestholmen, with SRB present in smaller numbers. A different microbial population was found in deep saline groundwater from Haestholmen and Olkiluoto that consists of a large proportion of a saline or brine end member. No SRB or AA bacteria were cultured; instead, the microbial population consisted of HA bacteria and either IRB or methanogens. In Olkiluoto, SRB predominated in the brackish and saline groundwater at depths to about 500 m, while methanogens were found in deeper saline groundwater. Stable isotope data (C-13) indicated that the methanogens are part of an autotrophic population consuming dissolved inorganic carbon (DIC) and hydrogen and producing methane and organic carbon. This deep ecosystem may be independent of surface life processes. A high-level radioactive waste (HLW) repository at 500 m depth in the Fennoscandian Shield will be inhabited by SRB, IRB and acetogens. Methanogens may also be present. These anaerobic micro

  7. Groundwater surface water interaction study using natural isotopes tracer

    Science.gov (United States)

    Yoon, Yoon Yeol; Kim, Yong Chul; Cho, Soo Young; Lee, Kil Yong

    2015-04-01

    Tritium and stable isotopes are a component of the water molecule, they are the most conservative tracer for groundwater study. And also, radon is natural radioactive nuclide and well dissolved in groundwater. Therefore, these isotopes are used natural tracer for the study of surface water and groundwater interaction of water curtain greenhouse area. The study area used groundwater as a water curtain for warming tool of greenhouse during the winter, and is associated with issues of groundwater shortage while being subject to groundwater-river water interaction. During the winter time, these interactions were studied by using Rn-222, stable isotopes and H-3. These interaction was monitored in multi depth well and linear direction well of groundwater flow. And dam effect was also compared. Samples were collected monthly from October 2013 to April 2014. Radon and tritium were analyzed using Quantulus low background liquid scintillation counter and stable isotopes were analyzed using an IRIS (Isotope Ratio Infrared Spectroscopy ; L2120-i, Picarro). During the winter time, radon concentration was varied from 0.07 Bq/L to 8.9 Bq/L and different interaction was showed between dam. Surface water intrusion was severe at February and restored April when greenhouse warming was ended. The stable isotope results showed different trend with depth and ranged from -9.16 ‰ to -7.24 ‰ for δ 18O value, while the δD value was ranged from -57.86 ‰ to -50.98 ‰. The groundwater age as dated by H-3 was ranged 0.23 Bq/L - 0.59 Bq/L with an average value of 0.37 Bq/L.

  8. Anomalous fluoride concentration in groundwater - is it natural or pollution? A stable isotope approach.

    Science.gov (United States)

    Marimon, Maria Paula Casagrande; Knöller, Kay; Roisenberg, Ari

    2007-06-01

    Fluoride anomalies (up to 11 mg/l) have been detected in groundwater of the central region of Rio Grande do Sul State, Southern Brazil, in an area where fluorosis is endemic. Two hypotheses are investigated concerning the fluoride origin: lithochemical affiliation from regional rock or contamination by fertilisers application. These hypotheses are discussed based on the stable isotope data of water, nitrate, and sulphate, which indicates that the local precipitation is the main groundwater recharge source. The isotopic composition of groundwater sulphate is similar to that of fertiliser sulphate. However, a conclusive assignment of groundwater sulphate to fertiliser origin is not indicated because further possible sulphate sources fall into the same isotopic range. In contrast, the isotopic composition of dissolved nitrate suggests that there is no direct relationship to the use of NPK fertilisers. Hence, an origin of the high fluoride content in groundwater related to long-term rock-water interactions seems likely.

  9. Groundwater Quality in Jingyuan County, a Semi-Humid Area in Northwest China

    Directory of Open Access Journals (Sweden)

    Wu Jianhua

    2011-01-01

    Full Text Available Groundwater quality assessment is an essential study which plays an important role in the rational development and utilization of groundwater in any part of the world. In the study, groundwater qualities in Jingyuan County, in Ningxia, China were assessed with entropy weighted water quality index method. In the assessment, 12 hydrochemical parameters including chloride, sulphate, sodium, iron, pH, total dissolved solid (TDS, total hardness (TH, nitrate, ammonia, nitrogen, fluoride, iodine and nitrite were selected. The assessment results show that the concentrations of iodine, TH, iron and TDS are the most influencing parameters affecting the groundwater quality. The assessment results are rational and are in consistency with the results of filed investigation of which both indicates the groundwater in Jingyuan County is fit for drinking.

  10. Acidity and mineral composition of precipitation in Moscow: Influence of deicing salts

    Science.gov (United States)

    Eremina, I. D.; Aloyan, A. E.; Arutyunyan, V. O.; Larin, I. K.; Chubarova, N. E.; Yermakov, A. N.

    2015-11-01

    Monitoring data and analysis of the variation in acidity and mineral composition of atmospheric precipitation in Moscow in 2012 are presented. We have found that the chloride anions in the precipitation are largely caused by chlorides of deicing salts. Here, the chloride anions, along with metal chlorides (components of deicing salts), are partly caused by dissolved hydrogen chloride. The appearance of hydrogen chloride in the atmosphere of Moscow has been shown to result from heterophase chemical reactions involving deicing salts. We have obtained preliminary estimates for the scales of the effect of these salts on the mineral composition and acidity of precipitations in Moscow.

  11. Quantifying shallow and deep groundwater inputs to rivers with groundwater dating in hydrological observatories.

    Science.gov (United States)

    Aquilina, Luc; Marçais, Jean; Gauvain, Alexandre; Kolbe, Tamara; de Dreuzy, Jean-Raynald; Labasque, Thierry; Abbott, Benjamin W.; Vergnaud, Virginie; Chatton, Eliot; Thomas, Zahra; Ruiz, Laurent; Bour, Olivier; Pinay, Gilles

    2017-04-01

    River water derives in part from groundwater—water that has spent some time in the subsurface (e.g. soil, unsaturated zone, saturated zone). However, because groundwater residence times vary from months to millennia, determining the proportion of shallow and deep groundwater contribution can be challenging. Groundwater dating with anthropogenic gases and natural geochemical tracers can decipher the origin of groundwater contribution to rivers, particularly when repeat samplings are carried out in different hydrological conditions. Here, we present two different applications of this approach from three hydrological observatories (H+ hydrogeological network; Aghrys and Armorique observatories) in western France, all these observatories belonging to the OZCAR national network. We carried out a regional investigation of mean groundwater ages in hard rock aquifers in Brittany, using long-term chronicles from hydrological observatories and regional monitoring sites. We determined the mean residence-time (RT) and annual renewal rate (RR) of four compartments of these aquifers: the direct contribution of a very young water component (i.e. RT less than 1-2 yr), the upper variably saturated zone (RR 27-33%), the weathered layer (RR 1.8-2.1%) and the fractured zone (RR 0.1%). From these values and a nitrate chronicle, we were able to determine the respective contributions of each compartment to the largest river in Brittany, the Vilaine, which drains 30% of the region. We found that the deep fractured compartment with very slow renewal times contributed to 25-45% of river water in winter and 30-60% in summer. The very young water which includes direct precipitation and soil fluxes constituted 40-65% of the winter river water (Aquilina et al., 2012). To complement these estimates, we investigated the relationship between dissolved silica and groundwater age in the Armorique hydrological observatory in northern Brittany. We computed the silica concentration expected along the

  12. PROCESS OF DISSOLVING ZIRCONIUM ALLOYS

    Science.gov (United States)

    Shor, R.S.; Vogler, S.

    1958-01-21

    A process is described for dissolving binary zirconium-uranium alloys where the uranium content is about 2%. In prior dissolution procedures for these alloys, an oxidizing agent was added to prevent the precipitation of uranium tetrafluoride. In the present method complete dissolution is accomplished without the use of the oxidizing agent by using only the stoichiometric amount or slight excess of HF required by the zirconium. The concentration of the acid may range from 2M to 10M and the dissolution is advatageously carried out at a temperature of 80 deg C.

  13. Canada's groundwater resources

    National Research Council Canada - National Science Library

    Rivera, Alfonso

    2014-01-01

    Groundwater is essential for life in arid and semiarid region. It is also important in humid regions, and is one of the fundamental requirements for the maintenance of natural landscapes and aquatic ecosystem...

  14. Groundwater Capture Zones

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Source water protection areas are delineated for each groundwater-based public water supply system using available geologic and hydrogeologic information to...

  15. Estimation of Selenium Loads Entering the South Arm of Great Salt Lake, Utah, from May 2006 through March 2008

    Science.gov (United States)

    Naftz, David L.; Johnson, William P.; Freeman, Michael L.; Beisner, Kimberly; Diaz, Ximena; Cross, VeeAnn A.

    2009-01-01

    Discharge and water-quality data collected from six streamflow-gaging stations were used in combination with the LOADEST software to provide an estimate of total (dissolved + particulate) selenium (Se) load to the south arm of Great Salt Lake (GSL) from May 2006 through March 2008. Total estimated Se load to GSL during this time period was 2,370 kilograms (kg). The 12-month estimated Se load to GSL for May 1, 2006, to April 30, 2007, was 1,560 kg. During the 23-month monitoring period, inflows from the Kennecott Utah Copper Corporation (KUCC) Drain and Bear River outflow contributed equally to the largest proportion of total Se load to GSL, accounting for 49 percent of the total Se load. Five instantaneous discharge measurements at three sites along the railroad causeway indicate a consistent net loss of Se mass from the south arm to the north arm of GSL (mean = 2.4 kg/day, n = 5). Application of the average daily loss rate equates to annual Se loss rate to the north arm of 880 kg (56 percent of the annual Se input to the south arm). The majority of Se in water entering GSL is in the dissolved (less than 0.45 micron) state and ranges in concentration from 0.06 to 35.7 micrograms per liter (ug/L). Particulate Se concentration ranged from less than 0.05 to 2.5 ug/L. Except for the KUCC Drain streamflow-gaging station, dissolved (less than 0.45 um) inflow samples contain an average of 21 percent selenite (SeO32-) during two sampling events (May 2006 and 2007). Selenium concentration in water samples collected from four monitoring sites within GSL during May 2006 through August 2007 were used to understand how the cumulative Se load was being processed by various biogeochemical processes within the lake. On the basis of the Mann-Kendall test results, changes in dissolved Se concentration at the four monitoring sites indicate a statistically significant (90-percent confidence interval) upward trend in Se concentration over the 16-month monitoring period. Furthermore

  16. High-fluoride groundwater.

    Science.gov (United States)

    Rao, N Subba

    2011-05-01

    Fluoride (F(-)) is essential for normal bone growth, but its higher concentration in the drinking water poses great health problems and fluorosis is common in many parts of India. The present paper deals with the aim of establishment of facts of the chemical characteristics responsible for the higher concentration of F(-) in the groundwater, after understanding the chemical behavior of F(-) in relation to pH, total alkalinity (TA), total hardness (TH), carbonate hardness (CH), non-carbonate hardness (NCH), and excess alkalinity (EA) in the groundwater observed from the known areas of endemic fluorosis zones of Andhra Pradesh that have abundant sources of F(-)-bearing minerals of the Precambrians. The chemical data of the groundwater shows that the pH increases with increase F(-); the concentration of TH is more than the concentration of TA at low F(-) groundwater, the resulting water is represented by NCH; the TH has less concentration compared to TA at high F(-) groundwater, causing the water that is characterized by EA; and the water of both low and high concentrations of F(-) has CH. As a result, the F(-) has a positive relation with pH and TA, and a negative relation with TH. The operating mechanism derived from these observations is that the F(-) is released from the source into the groundwater by geochemical reactions and that the groundwater in its flowpath is subjected to evapotranspiration due to the influence of dry climate, which accelerates a precipitation of CaCO(3) and a reduction of TH, and thereby a dissolution of F(-). Furthermore, the EA in the water activates the alkalinity in the areas of alkaline soils, leading to enrichment of F(-). Therefore, the alkaline condition, with high pH and EA, and low TH, is a more conducive environment for the higher concentration of F(-) in the groundwater.

  17. Groundwater ages from the freshwater zone of the Edwards aquifer, Uvalde County, Texas—Insights into groundwater flow and recharge

    Science.gov (United States)

    Hunt, Andrew G.; Landis, Gary P.; Faith, Jason R.

    2016-02-23

    Tritium–helium-3 groundwater ages of the Edwards aquifer in south-central Texas were determined as part of a long-term study of groundwater flow and recharge in the Edwards and Trinity aquifers. These ages help to define groundwater residence times and to provide constraints for calibration of groundwater flow models. A suite of 17 samples from public and private supply wells within Uvalde County were collected for active and noble gases, and for tritium–helium-3 analyses from the confined and unconfined parts of the Edwards aquifer. Samples were collected from monitoring wells at discrete depths in open boreholes as well as from integrated pumped well-head samples. The data indicate a fairly uniform groundwater flow system within an otherwise structurally complex geologic environment comprised of regionally and locally faulted rock units, igneous intrusions, and karst features within carbonate rocks. Apparent ages show moderate, downward average, linear velocities in the Uvalde area with increasing age to the east along a regional groundwater flow path. Though the apparent age data show a fairly consistent distribution across the study area, many apparent ages indicate mixing of both modern (less than 60 years) and premodern (greater than 60 years) waters. This mixing is most evident along the “bad water” line, an arbitrary delineation of 1,000 milligrams per liter dissolved solids that separates the freshwater zone of the Edwards aquifer from the downdip saline water zone. Mixing of modern and premodern waters also is indicated within the unconfined zone of the aquifer by high excess helium concentrations in young waters. Excess helium anomalies in the unconfined aquifer are consistent with possible subsurface discharge of premodern groundwater from the underlying Trinity aquifer into the younger groundwater of the Edwards aquifer.

  18. Impacts of Groundwater Recharge from Rubber Dams on the Hydrogeological Environment in Luoyang Basin, China

    Science.gov (United States)

    Dong, Shaogang; Liu, Baiwei; Liu, Huamin; Wang, Shidong; Wang, Lixin

    2014-01-01

    In the rubber dam's impact area, the groundwater total hardness (TH) has declined since 2000, ultimately dropping to 100–300 mg/L in 2012. pH levels have shown no obvious changes. NH4-N concentration in the groundwater remained stable from 2000 to 2006, but it increased from 2007 to 2012, with the largest increase up to 0.2 mg/L. NO3-N concentration in the groundwater generally declined in 2000–2006 and then increased from 2007; the largest increase was to 10 mg/L in 2012. Total dissolved solids (TDS) of the groundwater showed a general trend of decline from 2000 to 2009, but levels increased after 2010, especially along the south bank of the Luohe River where the largest increase recorded was approximately 100 mg/L. This study has shown that the increases in the concentrations of NH4-N and NO3-N were probably caused by changes in groundwater levels. Nitrates adsorbed by the silt clay of aeration zone appear to have entered the groundwater through physical and chemical reactions. TDS increased because of groundwater evaporation and some soluble ions entered the groundwater in the unsaturated zone. The distance of the contaminant to the surface of the aquifer became shorter due to the shallow depth of groundwater, resulting in the observed rise in pollutant concentrations more pronounced. PMID:25126593

  19. Impacts of Groundwater Recharge from Rubber Dams on the Hydrogeological Environment in Luoyang Basin, China

    Directory of Open Access Journals (Sweden)

    Shaogang Dong

    2014-01-01

    Full Text Available In the rubber dam’s impact area, the groundwater total hardness (TH has declined since 2000, ultimately dropping to 100–300 mg/L in 2012. pH levels have shown no obvious changes. NH4-N concentration in the groundwater remained stable from 2000 to 2006, but it increased from 2007 to 2012, with the largest increase up to 0.2 mg/L. NO3-N concentration in the groundwater generally declined in 2000–2006 and then increased from 2007; the largest increase was to 10 mg/L in 2012. Total dissolved solids (TDS of the groundwater showed a general trend of decline from 2000 to 2009, but levels increased after 2010, especially along the south bank of the Luohe River where the largest increase recorded was approximately 100 mg/L. This study has shown that the increases in the concentrations of NH4-N and NO3-N were probably caused by changes in groundwater levels. Nitrates adsorbed by the silt clay of aeration zone appear to have entered the groundwater through physical and chemical reactions. TDS increased because of groundwater evaporation and some soluble ions entered the groundwater in the unsaturated zone. The distance of the contaminant to the surface of the aquifer became shorter due to the shallow depth of groundwater, resulting in the observed rise in pollutant concentrations more pronounced.

  20. Potassium ferrate treatment of RFETS` contaminated groundwater

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-01-01

    The potassium ferrate treatment study of Rocky Flats Environmental Technology Site (RFETS) groundwater was performed under the Sitewide Treatability Studies Program (STSP). This study was undertaken to determine the effectiveness of potassium ferrate in a water treatment system to remove the contaminants of concern (COCS) from groundwater at the RFETS. Potassium ferrate is a simple salt where the iron is in the plus six valence state. It is the iron at the plus six valence state (Fe {sup +6}) that makes it an unique water treatment chemical, especially in waters where the pH is greater than seven. In basic solutions where the solubility of the oxides/hydroxides of many of the COCs is low, solids are formed as the pH is raised. By using ferrate these solids are agglomerated so they can be effectively removed by sedimentation in conventional water treatment equipment. The objective of this study was to determine the quality of water after treatment with potassium ferrate and to determine if the Colorado Water Quality Control Commission (CWQCC) discharge limits for the COCs listed in Table 1.0-1 could be met. Radionuclides in the groundwater were of special concern.

  1. Hydrochemical characteristics of rural community groundwater supply in Blantyre, southern Malawi

    Science.gov (United States)

    Mapoma, Harold Wilson Tumwitike; Xie, Xianjun; Zhang, Liping; Nyirenda, Mathews Tananga; Maliro, Albert; Chimutu, Darlington

    2016-02-01

    The purpose of this research was to characterize the quality of groundwater for drinking and irrigation in Blantyre, Malawi as well as identify some geochemical processes governing mineralization of major and some minor elements. The aquifer studied is part of the extensive crystalline basement complex. The suitability and classification involved confirmatory analysis of the results with World Health Organization and Malawi Standards Board groundwater guideline values. The water samples were analyzed for major descriptors (pH, Temperature, turbidity, major ions, total dissolved solids and electrical conductivity (EC), using standard methods. Besides, arsenic, iron and fluoride were analyzed as well. Multivariate statistics (especially Hierarchical Cluster Analysis and Factor Analysis), hydrographical methods (i.e. Piper diagram) and geochemical modeling programs (AquaChem and PHREEQC) were used to characterize the quality and explain the sources and evolution of groundwater. Suitability of groundwater for irrigation was assessed using Wilcox method which identified BH01, BH16 and BH21 as high salinity areas. Incidentally, the three boreholes had relatively higher sulfate and nitrate concentrations than the rest. Nevertheless, the groundwater was found to be within acceptable limits for drinking quality except elevated concentrations of nitrate, fluoride and iron in some boreholes compared with WHO standards, despite meeting the national standards. Borehole BH01, BH02, BH07, BH13 and BH18 exhibited nitrate concentrations greater than national standards (45 mg/L) an indication of groundwater contamination. Furthermore, the groundwater is slightly acidic to slightly above neutral with total dissolved solids less than 500 mg/l. Generally, groundwater was undersaturated with respect to both calcite and dolomite while oversaturated with respect to halite, goethite and hematite. Silicate and carbonate weathering were identified as main mineral sources for major ions in

  2. Fresh meteoric versus recirculated saline groundwater nutrient inputs into a subtropical estuary

    Energy Technology Data Exchange (ETDEWEB)

    Sadat-Noori, Mahmood, E-mail: mahmood.sadat-noori@scu.edu.au [National Marine Science Centre, School of Environment, Science and Engineering, Southern Cross University, Coffs Harbour, NSW (Australia); School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW (Australia); Santos, Isaac R. [National Marine Science Centre, School of Environment, Science and Engineering, Southern Cross University, Coffs Harbour, NSW (Australia); Tait, Douglas R. [National Marine Science Centre, School of Environment, Science and Engineering, Southern Cross University, Coffs Harbour, NSW (Australia); School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW (Australia); Maher, Damien T. [School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW (Australia)

    2016-10-01

    The role of groundwater in transporting nutrients to coastal aquatic systems has recently received considerable attention. However, the relative importance of fresh versus saline groundwater-derived nutrient inputs to estuaries and how these groundwater pathways may alter surface water N:P ratios remains poorly constrained. We performed detailed time series measurements of nutrients in a tidal estuary (Hat Head, NSW, Australia) and used radium to quantify the contribution of fresh and saline groundwater to total surface water estuarine exports under contrasting hydrological conditions (wet and dry season). Tidally integrated nutrient fluxes showed that the estuary was a source of nutrients to the coastal waters. Dissolved inorganic nitrogen (DIN) export was 7-fold higher than the average global areal flux rate for rivers likely due to the small catchment size, surrounding wetlands and high groundwater inputs. Fresh groundwater discharge was dominant in the wet season accounting for up to 45% of total dissolved nitrogen (TDN) and 48% of total dissolved phosphorus (TDP) estuarine exports. In the dry season, fresh and saline groundwater accounted for 21 and 33% of TDN export, respectively. The combined fresh and saline groundwater fluxes of NO{sub 3}, PO{sub 4}, NH{sub 4}, DON, DOP, TDN and TDP were estimated to account for 66, 58, 55, 31, 21, 53 and 47% of surface water exports, respectively. Groundwater-derived nitrogen inputs to the estuary were responsible for a change in the surface water N:P ratio from typical N-limiting conditions to P-limiting as predicted by previous studies. This shows the importance of both fresh and saline groundwater as a source of nutrients for coastal productivity and nutrient budgets of coastal waters. - Highlights: • Groundwater TDN and TDP fluxes account for 53 and 47% of surface water exports. • The estuary DIN export was 7-fold higher than the average global areal flux. • Fresh GW nutrient input dominated the wet season and

  3. Impact of soil and groundwater corrosion on the Hierakonpolis Temple Town archaeological site, Wadi Abu Sufian, Idfu, Egypt.

    Science.gov (United States)

    El-Shishtawy, A M; Atwia, M G; El-Gohary, A; Parizek, R R

    2013-06-01

    -grained Nile alluvium is characterized by high salinity which varies from 415 to 4,500 mg/L total dissolved solids. In contrast, most of the groundwater samples in the lower zone (Quaternary aquifer) are characterized by a low salinity in the order of 164-792 mg/L. Values of δD and δO(18) obtained from this deep (9-20 m) aquifer ranged from 16.98 to 19.87 ‰ and from 1.67 to 2.99 ‰, respectively. These values indicated that the Quaternary aquifer waters are recharged directly from recent Nile water. Subsoil water is very shallow in the area; it ranged from 0 to 2.6 m with a mean of 1.1 m within the main mound of the Hierakonpolis Temple Town site by 2003, in contrast to its more than 4.5-m depth in 1897. The exposure of subsoil water to increased evaporation is expected, with a consequent increase in the concentrations of dissolved solids and usually large proportions of chloride and sulfate. Artifacts recovered from the Temple Town site are becoming damaged and destroyed by crystallization processes caused by repeated wetting and drying of salt and the accumulation of new salts.

  4. Hydrogeology of the western part of the Salt River Valley area, Maricopa County, Arizona

    Science.gov (United States)

    Brown, James G.; Pool, D.R.

    1989-01-01

    The Salt River Valley is a major population and agricultural center of more than 3,000 mi2 in central Arizona (fig. 1). The western part of the Salt River Valley area (area of this report) covers about 1,500 mi2. The Phoenix metropolitan area with a population of more than 1.6 million in 1985 (Valley National Bank, 1987) is located within the valley. The watersheds of the Salt, Verde, and Agua Fria Rivers provide the valley with a reliable but limited surface-water supply that must be augmented with ground water even in years of plentiful rainfall. Large-scale ground-water withdrawals began in the Salt River Valley in the early part of the 20th century; between 1915 and 1983, the total estimated ground-water pumpage was 81 million acre-ft (U.S. Geological Survey, 1984). Because of the low average annual rainfall and high potential evapotranspiration, the principal sources of ground-water recharge are urban runoff, excess irrigation, canal seepage and surface-water flows during years of higher-than-normal rainfall. Withdrawals greatly exceed recharge and, in some area, ground-water levels have declines as much as 350 ft (Laney and other, 1978; Ross, 1978). In the study area, ground-water declines of more than 300 ft have occurred in Deer Valley and from Luke Air Force Base north to Beardsley. As a result, a large depression of the water table has developed west of Luke Air Force Base (fig. 2). Ground-water use has decreased in recent years because precipitation and surface-water supplies have been greater than normal. Increased precipitation also caused large quantities of runoff to be released into the normally dry Salt and Gila River channels. From February 1978 to June 1980, streamflow losses of at least 90,000 acre-ft occurred between Jointhead Dam near the east boundary of the study area and Gillespie Dam several miles southwest of the west edge of the study area (Mann and Rhone, 1983). Consequently, ground-water declines in a large part of the basin have

  5. Self-accelerated development of salt karst during flash floods along the Dead Sea Coast, Israel

    Science.gov (United States)

    Avni, Yoav; Lensky, Nadav; Dente, Elad; Shviro, Maayan; Arav, Reuma; Gavrieli, Ittai; Yechieli, Yoseph; Abelson, Meir; Lutzky, Hallel; Filin, Sagi; Haviv, Itai; Baer, Gidon

    2016-01-01

    We document and analyze the rapid development of a real-time karst system within the subsurface salt layers of the Ze'elim Fan, Dead Sea, Israel by a multidisciplinary study that combines interferometric synthetic aperture radar and light detection and ranging measurements, sinkhole mapping, time-lapse camera monitoring, groundwater level measurements and chemical and isotopic analyses of surface runoff and groundwater. The >1 m/yr drop of Dead Sea water level and the subsequent change in the adjacent groundwater system since the 1960s resulted in flushing of the coastal aquifer by fresh groundwater, subsurface salt dissolution, gradual land subsidence and formation of sinkholes. Since 2010 this process accelerated dramatically as flash floods at the Ze'elim Fan were drained by newly formed sinkholes. During and immediately after these flood events the dissolution rates of the subsurface salt layer increased dramatically, the overlying ground surface subsided, a large number of sinkholes developed over short time periods (hours to days), and salt-saturated water resurged downstream. Groundwater flow velocities increased by more than 2 orders of magnitudes compared to previously measured velocities along the Dead Sea. The process is self-accelerating as salt dissolution enhances subsidence and sinkhole formation, which in turn increase the ponding areas of flood water and generate additional draining conduits to the subsurface. The rapid terrain response is predominantly due to the highly soluble salt. It is enhanced by the shallow depth of the salt layer, the low competence of the newly exposed unconsolidated overburden and the moderate topographic gradients of the Ze'elim Fan.

  6. Continuous in-situ monitoring of dissolved gases for the characterization of the Critical Zone with a MIMS

    Science.gov (United States)

    Chatton, Eliot; Labasque, Thierry; Aquilina, Luc; de la Bernardie, Jérôme; Guihéneuf, Nicolas

    2016-04-01

    In the perspective of a temporal and spatial exploration of the Critical Zone, we developed an in situ monitoring instrument for continuous dissolved gas analysis (N2, O2, CO2, CH4, He, Ne, Ar, Kr, Xe). With a large resolution (5 orders of magnitude) and a capability of high frequency multi-tracer analysis (1 gas every 1.5 seconds), the MIMS (Membrane Inlet Mass Spectrometer) is an innovative tool allowing the investigation of a large panel of physical and biogeochemical processes. First of all, this study presents the results of groundwater tracer tests using dissolved gases in order to evaluate transport properties of a fractured media in Brittany, France (Ploemeur, ORE H+). The tracer test experiment showed that the MIMS is perfectly suitable for field work. The instrument provides precise measurements accurate enough to produce breakthrough curves during groundwater tracer tests. The results derived from 4He data gives transport parameters in good agreement with the results obtained with a fluorescent tracer. Combined with a pump and a multi-parameter probe, the MIMS is also capable to perform accurate dissolved gases well-logs allowing a real-time estimation of recharge conditions (temperature, excess air), aquifer stratification, redox conditions and groundwater residence time by 4He dating. Therefore, the MIMS is a valuable tool for in situ characterization of biogeochemical reactivity in aquatic systems, the determination of aquifer transport properties, the monitoring of groundwater recharge conditions and the characterization of aquifer-river exchanges.

  7. Evaluation of nitrate source in groundwater of southern part of North China Plain based on multi-isotope

    Institute of Scientific and Technical Information of China (English)

    方晶晶; 周爱国; 马传明; 刘存富; 蔡鹤生; 甘义群; 刘运德

    2015-01-01

    Nitrate pollution in groundwater is a serious water quality problem that increases the risk of developing various cancers. Groundwater is the most important water resource and supports a population of 5 million in Anyang area of the southern part of the North China Plain. Determining the source of nitrate pollution is the challenge in hydrology area due to the complex processes of migration and transformation. A new method is presented to determine the source of nitrogen pollution by combining the composition characteristics of stable carbon isotope in dissolved organic carbon in groundwater. The source of groundwater nitrate is dominated by agricultural fertilizers, as well as manure and wastewater. Mineralization, nitrification and mixing processes occur in the groundwater recharge area, whereas the confined groundwater area is dominated by denitrification processes.

  8. Ground-water hydrology of the Punjab region of West Pakistan, with emphasis on problems caused by canal irrigation

    Science.gov (United States)

    Greenman, D.W.; Swarzenski, W.V.; Bennett, G.D.

    1967-01-01

    Rising water tables and the salinization of land as the result of canal irrigation threaten the agricultural economy of the Punjab. Since 1954 the Water and Soils Investigation Division of the West Pakistan Water and Power Development Authority has inventoried the water and soils resources of the Punjab and investigated the relations between irrigation activities, the natural hydrologic factors, and the incidence of waterlogging and subsurface-drainage problems. This report summarizes the findings of the investigation, which was carried out under a cooperative agreement between the Government of Pakistan and the U.S. Agency for International Development, and its predecessor, the U.S. International Cooperation Administration. Leakage from the canal systems, some of which have been in operation for more than 100 years, is the principal cause of rising water levels and constitutes the major component of ground-water recharge in the Punjab. Geologic studies have shown that virtually the entire Punjab is underlain to depths of 1,000 feet or more by unconsolidated alluvium, which is saturated to within a few feet of land surface. The alluvium varies in texture from medium sand to silty clay, but sandy sediments predominate. Large capacity wells, yielding 4 cfs or more, can be developed almost everywhere. Ground water occurring within a depth of 500 feet below the surface averages less than 1,000 ppm of dissolved solids throughout approximately two-thirds of the Punjab. It is estimated that the volume of usable ground water in storage in this part of the alluvial aquifer is on the order of 2 billion acre-feet. In the other one-third of the Punjab, total dissolved solids range from 1,000 to about 20,000 ppm. In about one-half of this area (one-sixth of the area of the Punjab) some ground water can be utilized by diluting with surface water from canals. The ground-water reservoir underlying the Punjab is an unexploited resource of enormous economic value. It is recognized

  9. Characterization of DOM in landfill leachate polluted groundwater with electrospary LC-MS

    DEFF Research Database (Denmark)

    Persson, L.; Alsberg, T.; Odham, G.

    2001-01-01

    Dissolved organic matter in leachate polluted groundwater, downgradient a landfill, was analysed with electrospray mass spectrometry. The results indicate that the DOM change qualitatively in the gradient, becoming more uniform in functional groups and hydrofobicity. Those changes may affect...... the DOM facilitated transport of pollutants....

  10. Quantification of conservative and reactive transport using a single groundwater tracer test in a fractured media

    Science.gov (United States)

    Chatton, Eliot; Labasque, Thierry; Guillou, Aurélie; Béthencourt, Lorine; de La Bernardie, Jérôme; Boisson, Alexandre; Koch, Florian; Aquilina, Luc

    2017-04-01

    Identification of biogeochemical reactions in aquifers and determining kinetics is important for the prediction of contaminant transport in aquifers and groundwater management. Therefore, experiments accounting for both conservative and reactive transport are essential to understand the biogeochemical reactivity at field scale. This study presents the results of a groundwater tracer test using the combined injection of dissolved conservative and reactive tracers (He, Xe, Ar, Br-, O2 and NO3-) in order to evaluate the transport properties of a fractured media in Brittany, France. Dissolved gas concentrations were continuously monitored in situ with a CF-MIMS (Chatton et al, 2016) allowing a high frequency (1 gas every 2 seconds) multi-tracer analysis (N2, O2, CO2, CH4, N2O, H2, He, Ne, Ar, Kr, Xe) over a large resolution (6 orders of magnitude). Along with dissolved gases, groundwater biogeochemistry was monitored through the sampling of major anions and cations, trace elements and microbiological diversity. The results show breakthrough curves allowing the combined quantification of conservative and reactive transport properties. This ongoing work is an original approach investigating the link between heterogeneity of porous media and biogeochemical reactions at field scale. Eliot Chatton, Thierry Labasque, Jérôme de La Bernardie, Nicolas Guihéneuf, Olivier Bour and Luc Aquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and Biogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016.

  11. Test/QA Plan for Verification of Nitrate Sensors for Groundwater Remediation Monitoring

    Science.gov (United States)

    A submersible nitrate sensor is capable of collecting in-situ measurements of dissolved nitrate concentrations in groundwater. Although several types of nitrate sensors currently exist, this verification test will focus on submersible sensors equipped with a nitrate-specific ion...

  12. Influence of volcanic history on groundwater patterns on the west slope of the Oregon High Cascades.

    Science.gov (United States)

    A. Jefferson; G. Grant; T. Rose

    2006-01-01

    Spring systems on the west slope of the Oregon High Cascades exhibit complex relationships among modern topography, lava flow geometries, and groundwater flow patterns. Seven cold springs were continuously monitored for discharge and temperature in the 2004 water year, and they were periodically sampled for ?18O, ?D, tritium, and dissolved noble gases. Anomalously high...

  13. Geochemical evolution of groundwater in the Culebra dolomite near the Waste Isolation Pilot Plant, southeastern New Mexico, USA

    Science.gov (United States)

    Siegel, M.D.; Anderholm, S.

    1994-01-01

    The Culebra Dolomite Member of the Rustler Formation, a thin (10 m) fractured dolomite aquifer, lies approximately 450 m above the repository horizon of the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico, USA. Salinities of water in the Culebra range roughly from 10,000 to 200,000 mg/L within the WIPP site. A proposed model for the post-Pleistocene hydrochemical evolution of the Culebra tentatively identifies the major sources and sinks for many of the groundwater solutes. Reaction-path simulations with the PHRQPITZ code suggest that the Culebra dolomite is a partial chemical equilibrium system whose composition is controlled by an irreversible process (dissolution of evaporites) and equilibrium with gypsum and calcite. Net geochemical reactions along postulated modern flow paths, calculated with the NETPATH code, include dissolution of halite, carbonate and evaporite salts, and ion exchange. R-mode principal component analysis revealed correlations among the concentrations of Si, Mg, pH, Li, and B that are consistent with several clay-water reactions. The results of the geochemical calculations and mineralogical data are consistent with the following hydrochemical model: 1. (1) solutes are added to the Culebra by dissolution of evaporite minerals 2. (2) the solubilities of gypsum and calcite increase as the salinity increases; these minerals dissolve as chemical equilibrium is maintained between them and the groundwater 3. (3) equilibrium is not maintained between the waters and dolomite; sufficient Mg is added to the waters by dissolution of accessory carnallite or polyhalite such that the degree of dolomite supersaturation increases with ionic strength 4. (4) clays within the fractures and rock matrix exert some control on the distribution of Li, B, Mg, and Si via sorption, ion exchange, and dissolution. ?? 1994.

  14. Limits to global groundwater consumption

    Science.gov (United States)

    de Graaf, I.; Van Beek, L. P.; Sutanudjaja, E.; Wada, Y.; Bierkens, M. F.

    2016-12-01

    Groundwater is the largest accessible freshwater resource worldwide and is of critical importance for irrigation, and so for global food security. For many regions of the world where groundwater abstraction exceeds groundwater recharge, persistent groundwater depletion occurs. A direct consequence of depletion is falling groundwater levels, reducing baseflows to rivers, harming ecosystems. Also, pumping costs increase, wells dry up and land subsidence can occur. Water demands are expected to increase further due to growing population, economic development and climate change, posing the urgent question how sustainable current water abstractions are worldwide and where and when these abstractions approach conceivable limits with all the associated problems. Here, we estimated past and future trends (1960-2050) in groundwater levels resulting from changes in abstractions and climate and predicted when limits of groundwater consumption are reached. We explored these limits by predicting where and when groundwater levels drop that low that groundwater becomes unattainable for abstractions and how river flows are affected. Water availabilities, abstractions, and lateral groundwater flows are simulated (5 arcmin. resolution) using a coupled version of the global hydrological model PCR-GLOBWB and a groundwater model based on MODFLOW. The groundwater model includes a parameterization of the worlds confined and unconfined aquifer systems, needed for a realistic simulation of groundwater head dynamics. Results show that, next to the existing regions experiencing groundwater depletion (like India, Pakistan, Central Valley) new regions will develop, e.g. Southern Europe, the Middle East, and Africa. Using a limit that reflects present-day feasibility of groundwater abstraction, we estimate that in 2050 groundwater becomes unattainable for 20% of the global population, mainly in the developing countries and pumping cost will increase significantly. Largest impacts are found

  15. Volcanic degassing at Somma-Vesuvio (Italy) inferred by chemical and isotopic signatures of groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Caliro, S. [Osservatorio Vesuviano sezione di Napoli dell' Istituto, Nazionale Geofisica Vulcanologia, Via Diocleziano 328, 80124 Naples (Italy)]. E-mail: caliro@ov.ingv.it; Chiodini, G. [Osservatorio Vesuviano sezione di Napoli dell' Istituto, Nazionale Geofisica Vulcanologia, Via Diocleziano 328, 80124 Naples (Italy); Avino, R. [Osservatorio Vesuviano sezione di Napoli dell' Istituto, Nazionale Geofisica Vulcanologia, Via Diocleziano 328, 80124 Naples (Italy); Cardellini, C. [Dipartimento di Scienze della Terra, Universita di Perugia (Italy); Frondini, F. [Dipartimento di Scienze della Terra, Universita di Perugia (Italy)

    2005-06-15

    A geochemical model is proposed for water evolution at Somma-Vesuvio, based on the chemical and isotopic composition of groundwaters, submarine gas emission and chemical composition of the dissolved gases. The active degassing processes, present in the highest part of the volcano edifice, strongly influence the groundwater evolution. The geological-volcanological setting of the volcano forces the waters infiltrating at Somma-Vesuvio caldera, enriched in volcanic gases, to flow towards the southern sector to an area of high pCO{sub 2} groundwaters. Reaction path modelling applied to this conceptual model, involving gas-water-rock interaction, highlights an intense degassing process in the aquifer controlling the chemical and isotopic composition of dissolved gases, total dissolved inorganic C (TDIC) and submarine gas emission. Mapping of TDIC shows a unique area of high values situated SSE of Vesuvio volcano with an average TDIC value of 0.039 mol/L, i.e., one order of magnitude higher than groundwaters from other sectors of the volcano. On the basis of TDIC values, the amount of CO{sub 2} transported by Vesuvio groundwaters was estimated at about 150 t/d. This estimate does not take into account the fraction of gas loss by degassing, however, it represents a relevant part of the CO{sub 2} emitted in this quiescent period by the Vesuvio volcanic system, being of the same order of magnitude as the CO{sub 2} diffusely degassed from the crater area.

  16. Groundwater chemistry of shallow aquifers in the coastal zones of Cochin, India

    Digital Repository Service at National Institute of Oceanography (India)

    Laluraj, C.M.; Gopinath, G.; DineshKumar, P.K.

    chloride was determined by argentometric titration using standard silver nitrate as reagent. Carbonate and bicarbonate concentrations of the groundwater were determined titrimetrically [2, 14]. Sulphate concentration was carried out following turbidity....A.J & Geirnaert, W. (1991): Process accompanying the intrusion of salt water. – In: Breuk, W. de (ed.): Hydogeology of salt water intrusion, a selection of SWIM papers. I.A.H. v. 11/1991, Verlag Heinz Heise. [4] Back, W. (1960): Origin of hydrochemical facies...

  17. SALT for Language Acquisition.

    Science.gov (United States)

    Bancroft, W. Jane

    1996-01-01

    Discusses Schuster's Suggestive-Accelerative Learning Techniques (SALT) Method, which combines Lozanov's Suggestopedia with such American methods as Asher's Total Physical Response and Galyean's Confluent Education. The article argues that students trained with the SALT Method have higher achievement scores and better attitudes than others. (14…

  18. Hydroxycarboxylic acids and salts

    Energy Technology Data Exchange (ETDEWEB)

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  19. SALT for Language Acquisition.

    Science.gov (United States)

    Bancroft, W. Jane

    1996-01-01

    Discusses Schuster's Suggestive-Accelerative Learning Techniques (SALT) Method, which combines Lozanov's Suggestopedia with such American methods as Asher's Total Physical Response and Galyean's Confluent Education. The article argues that students trained with the SALT Method have higher achievement scores and better attitudes than others. (14…

  20. Geological factors controlling radon hazardous concentration in groundwater

    Science.gov (United States)

    Przylibski, T. A.

    2009-04-01

    Radon waters are classified as waters containing more than 100 Bq/L of Rn-222. In many regions radon groundwaters are commonly used as a tap waters. Exploitation of radon groundwater without removing radon out of water in the intake may be hazardous for the consumers. Radon removing is relatively simple and cheap, and may be achieved trough the degassing of tapped water. The following factors are crucial for the genesis of radon (Rn-222) and changes in its concentration in groundwaters: the content of parent Ra-226 in the reservoir rock, the emanation coefficient of the reservoir rock, mixing of various groundwater components. Simplifying the geochemical characterisctics of Ra-226, one can say that the highest radium contents outside uranium deposits could be expected above all in crystalline rocks such as granites, ryolites and gneisses, and among sedimentary rocks - in fine-grained rocks - mudstones and clay rocks. Therefore the highest content of Rn-222 is characteristic of groundwaters flowing through the abovementioned rocks. What is very important for the genesis of groundwater dissolved Rn-222 is not only the total content of Ra-226 in the aquifer, but also the distribution of this isotope's atoms in relation to the surface of mineral grains (crystals) and crack surfaces. Only if Ra-226 atoms lie in the outer zone of grains (crystals), they can be the source of Rn-222 atoms released directly or indirectly into pores and fissures. If the pores and fissures are filled with free groundwater, then the radon dissolved in this water can migrate with it. Therefore particularly high Rn-222 concentration values can be expected in groundwaters circulating in zones of strongly cracked reservoir rocks, i.e. in the weathering zone, reaching the depth of several dozen meters below ground surface, as well as in zones of brittle tectonic deformations. The number of Rn-222 atoms formed in groundwater as a result of the decay of Ra-226 ion (Ra2+) dissolved in this water

  1. Groundwater Resources of Ribeira Paul Basin, Island of Santo Antao, Cape Verde, West Africa

    Science.gov (United States)

    Heilweil, Victor M.; Gingerich, Stephen B.; Verstraeten, Ingrid M.

    2010-01-01

    Groundwater resources in Cape Verde provide water for agriculture, industry, and human consumption. These resources are limited and susceptible to contamination. Additional groundwater resources are needed for continued agricultural development, particularly during times of drought, but increased use and (or) climatic change may have adverse effects on the quantity and quality of freshwater available. In volcanic island aquifers such as those of Cape Verde, a lens of fresh groundwater typically ?floats? upon a layer of brackish water at the freshwater/saltwater boundary, and increased pumping may cause salt water intrusion or other contamination. A recent U.S. Geological Survey study assessed baseline groundwater conditions in watersheds on three islands of Cape Verde to provide the scientific basis for sustainably developing water resources and minimizing future groundwater depletion and contamination.

  2. Groundwater Resources of Ribeira Faja Basin, Island of Sao Nicolau, Cape Verde, West Africa

    Science.gov (United States)

    Heilweil, Victor M.; Gingerich, Stephen B.; Plummer, L. Niel; Verstraeten, Ingrid M.

    2010-01-01

    Groundwater resources in Cape Verde provide water for agriculture, industry, and human consumption. These resources are limited and susceptible to contamination. Additional groundwater resources are needed for continued agricultural development, particularly during times of drought, but increased use and (or) climatic change may have adverse effects on the quantity and quality of freshwater available. In volcanic island aquifers such as those of Cape Verde, a lens of fresh groundwater typically ?floats? upon a layer of brackish water at the freshwater/saltwater boundary, and increased pumping may cause salt water intrusion or other contamination. A recent U.S. Geological Survey study assessed baseline groundwater conditions in watersheds on three islands of Cape Verde to provide the scientific basis for sustainably developing water resources and minimizing future groundwater depletion and contamination.

  3. Groundwater Resources of Mosteiros Basin, Island of Fogo, Cape Verde, West Africa

    Science.gov (United States)

    Heilweil, Victor M.; Gingerich, Stephen B.; Plummer, L. Niel; Verstraeten, Ingrid M.

    2010-01-01

    Groundwater resources in Cape Verde provide water for agriculture, industry, and human consumption. These resources are limited and susceptible to contamination. Additional groundwater resources are needed for continued agricultural development, particularly during times of drought, but increased use and (or) climatic change may have adverse effects on the quantity and quality of freshwater available. In volcanic island aquifers such as those of Cape Verde, a lens of fresh groundwater typically ?floats? upon a layer of brackish water at the freshwater/saltwater boundary, and increased pumping may cause salt water intrusion or other contamination. A recent U.S. Geological Survey study assessed baseline groundwater conditions in watersheds on three islands of Cape Verde to provide the scientific basis for sustainably developing water resources and minimizing future groundwater depletion and contamination.

  4. Factors controlling the evolution of groundwater dynamics and chemistry in the Senegal River Delta

    Directory of Open Access Journals (Sweden)

    Abdoul Aziz Gning

    2017-04-01

    New hydrological insights for the region: Results show that groundwater far away from rivers and outside irrigated plots has evolved from marine water to brines under the influence of evapotranspiration. Near rivers, salinity of groundwater is lower than seawater and groundwater mineralization seems to evolve in the direction of softening through cationic exchanges related to permanent contact with fresh water. Despite large volumes of water used for rice cultivation, groundwater does not show any real softening trend in the cultivated parcels. Results show that the mechanisms that contribute to repel salt water from the sediments correspond to a lateral flush near permanent surface water streams and not to vertical drainage and dilution with rainfall or irrigation water. It is however difficult to estimate the time required to come back to more favorable conditions of groundwater salinity.

  5. Geologic influence on groundwater salinity drives large seawater circulation through the continental shelf

    Science.gov (United States)

    Michael, Holly A.; Scott, Kaileigh C.; Koneshloo, Mohammad; Yu, Xuan; Khan, Mahfuzur R.; Li, Katie

    2016-10-01

    Observations of offshore freshened groundwater and saline groundwater discharge along continental shelves have important implications for water resources, ecosystem function, and the composition of the ocean, but they cannot be explained by basic theory. We show that these independent observations are linked and result from processes that drive variable-density groundwater flow through the spatial heterogeneity that is ubiquitous in geologic formations. We use lithologic data to develop geostatistical models that mimic the architecture of coastal aquifers. Simulation of groundwater flow and salt transport through these random realizations shows that heterogeneity produces spatially complex subsurface salinity distributions that extend tens of kilometers offshore, even at steady state. The associated density gradients drive high saline groundwater circulation rates that cannot be predicted by equivalent homogeneous models. Results suggest that these phenomena may be common along continental shelves, potentially altering estimates of ocean chemical budgets and impacting coastal water management for future generations.

  6. Determinants of Shallow Groundwater As Variability in Bangladesh

    Science.gov (United States)

    Radloff, K. A.; Zheng, Y.; Stute, M.; Rahman, M.; Mihajlov, I.; Siu, H.; Huq, M.; Choudhury, I.; Ahmed, K.; van Geen, A.

    2010-12-01

    Manually operated tube wells that tap into shallow aquifers remain a critical source of untreated drinking water in south Asia and an estimated 37 million people are still exposed to elevated levels of As in Bangladesh(1). This field effort sought to address two questions. What mechanisms control the partitioning of As between groundwater and sediment? How does groundwater transport affect the spatial variability of dissolved As? Understanding the source of groundwater variability is essential for understanding how [As] will change with time, especially as Bangladesh and its water demands develop. Arsenic mobility and transport within the shallow aquifer was investigated at a 0.5 km2 site where [As] increases from 50 μg/L in the village within the next few decades. The rapid economic development of Bangladesh could induce similar changes in groundwater flow, and thus As concentrations, elsewhere. This suggests that periodic monitoring of shallow wells low in As within regions of where the As content of groundwater is variable is particularly important. The size of the pool of As adsorbed on the sediment also indicates that current attempts to flush Bangladeshi aquifers “clean” through increased pumping will likely be ineffective. 1. BBS/UNICEF. Bangladesh: Multiple Indicator Cluster Survey, 2009. (Dhaka, Bangladesh, 2009).

  7. Groundwater Quality Assessment in Jazan Region, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Adel M. Alhababy

    2015-04-01

    Full Text Available Jazan province is an arid area, located at the southwestern part of Saudi Arabia along the Red Sea coast. Groundwater is the only resource of drinking water in this area; thus, its suitability for drinking and domestic uses is of public and scientific concern. In this study, groundwater samples were collected from 23 sites in Jazan area during fall 2014; measurements and analysis of water quality parameters including pH, total dissolved solids TDS, turbidity, hardness, alkalinity, ammonia, nitrite, nitrate, sulfate, calcium, magnesium, chloride, iron and fluoride were carried out with references to WHO and Gulf Standardization Organization GSO. TDS values exceeded the permissible limit of 600 mg/l in 30.4% of samples, total hardness values exceeded the permissible limits of 300 mg/l in 34.8% of samples, and nitrate concentration exceeded the permissible limit of 50 mg/l in only one sample. However, the concentrations of investigated parameters in the groundwater samples were within the permissible limits of WHO. Our results showed that the water quality of groundwater in Jazan area is acceptable and could be used safely for drinking and domestic purposes. However, a special attention should be paid to the concentration of TDS and nitrate in groundwater in future studies.

  8. Groundwater geochemistry of a municipal landfill in Araras, SP

    Directory of Open Access Journals (Sweden)

    Carlos Frederico de Castro Alves 1

    2014-03-01

    Full Text Available A contaminated area associated with a residential unlined landfill, located in Araras, was investigated. The aim of this work was to develop a hydrogeological and geochemical conceptual model in order to identify the redox zones related to the landfill and to explain the main processes resulting from the impact of leachates on the local groundwaters and soil. The work consisted of a surface geological mapping, geophysical survey with electric tomography, logging of subsoil boreholes, an installation of monitoring wells and soil, gas, leachate and groundwater samples analyses. The results show that the Araras landfill is in the methanogenic phase and promotes alterations in local groundwater quality. The main parameters of environmental interest identified in the leachate were total dissolved solids, biochemical oxygen demand, ammonium, methane, Na, Cl, Fe, Mn, Ba, B, Co and Cd. According to criteria specifically developed for this landfill, the following redox zones were identified in the groundwater: (i aerobic, located upgradient from the landfill; (ii methanogenic, downgradient from the landfill; (iii iron and/or manganese reduction, located between the methanogenic zone and the Araras river. Bypassing the iron and/or manganese redox zone, the existence of a denitrification zone was inferred. Besides the redox reactions in these zones, other processes that mitigate the impact of leachate into groundwater were also discovered: dilution, degradation by the action of surface microorganisms, dispersion, ionic exchange, formation of organic and inorganic complexes, dissolution and precipitation.

  9. Impact of groundwater use as heat energy on coastal ecosystem and fisheries

    Science.gov (United States)

    Taniguchi, Makoto

    2016-04-01

    Demands for groundwater as a heat energy source to melt snow is increasing in many coastal snowy areas in Japan because of the lack of laborers for snow removal and the abundance of groundwater resources. The temperature of groundwater is relatively higher in winter than that of the air and river water, therefore it is a useful heat source to melt snow. However, groundwater is also beneficial for the coastal ecosystem and fishery production because of the nutrient discharge by submarine groundwater discharge (SGD), which is one of the water and dissolved material pathways from land to the ocean. Therefore, groundwater is involved in the tradeoff and management conflict existing between energy and food (fisheries). In this study, the impact of groundwater, used as a heat energy source for the melting of snow accumulated on roads, on the coastal ecosystem and fisheries has been analyzed in the snowy areas of Obama City, Fukui Prefecture, Japan. Positive correlation has been found between primary production rates in Obama Bay and radon concentrations which show the magnitude of the submarine groundwater discharge. Therefore, the increase in groundwater pumping on land reduces fishery production in the ocean. Results of 3D numerical simulations of the basin scale groundwater model show a reduction of SGD by 5 percent due to an increase in groundwater pumping by 1.5 times. This reduction of SGD caused a 3.7 ton decrease in fishery production under the aforementioned assumptions. The groundwater-energy-fishery nexus was found in Obama Bay, Japan and the tradeoff between water and food was evaluated.

  10. Groundwater hydrochemistry evolution in cyclone driven hydrological regimes, NW Australia

    Science.gov (United States)

    Skrzypek, G.; Dogramaci, S.; Grierson, P.

    2013-12-01

    Groundwater reserves supply the water needs of many arid regions around the world. Aquifer recharge in these regions is primarily depended on the amount and distribution of rainfall, coupled with exceedingly high rates of evaporation and interactions with both local and regional geomorphology and geology. In semi-arid northwest Australia, the majority of rainfall is delivered by large but infrequent cyclonic events and relatively more frequent but low intensity frontal systems. Changes to rainfall patterns due to global climate change may impact hydrological regimes, recharge rates and groundwater hydrochemistry. These changes may significantly restrict freshwater resources in the future. Between 2008 and 2012, we analysed >400 groundwater, surface and rainwater samples for stable isotope composition (δ2H and δ18O) and major ion chemistry. We then developed conceptual geochemical models of groundwater evolution for the Hamersley Basin (>100,000 km2) and a salt inventory for the Fortescue Marsh (the largest wetland in NW Australia) [1,2]. Fresh groundwater from the alluvium (-8.02 × 0.83‰) and fractured aquifers (-8.22 × 0.70‰) were hydrochemically similar and characterised by a very narrow range of δ18O [1]. In contrast, δ18O of saline and brine groundwater (TDS >10 g L-1) varies in wide range from +2.5 to -7.2‰ [2]. Most of the fresh and brackish groundwater reflects modern recharge and is evaporated by water and older deep groundwater. The Fortescue Marsh primarily acts as a terminal basin for surface water from the upper Fortescue River catchment [2]. The stable isotope composition of the deep brine groundwater under the Marsh suggests a complex evolution, which cannot be explained by evaporation under current climatic conditions. The observed salinity and δ18O values may result from progressive evaporation from highly saline lake that existed in the past, as the dynamic fractionation from brine is much different compared to that in fresh and

  11. Geomechanics of bedded salt

    Energy Technology Data Exchange (ETDEWEB)

    Serata, S.; Milnor, S.W.

    1979-06-08

    Creep data from the literature search is reinterpreted by SGI, resulting in a better understanding of the temperature and stress state dependence of the octahedral creep rate and the octahedral shear strength. The concept of a transition strength between the elastic and the plastic states is in agreement with the data. The elastic and rheological properties of salt are described, and a set of constitutive equations is presented. The dependence of material properties on parameters such as temperature is considered. Findings on the permeability of salt are summarized, and the in-situ behavior of openings in bedded salt is described based on extensive engineering experience. A stress measuring system utilizing a finite element computer code is discussed. Geological factors affecting the stability of salt openings are considered, and the Stress Control Technique for designing stable openings in bedded salt formations is explained.

  12. Salt Tolerance in Soybean

    Institute of Scientific and Technical Information of China (English)

    Tsui-Hung Phang; Guihua Shao; Hon-Ming Lam

    2008-01-01

    Soybean is an Important cash crop and its productivity is significantly hampered by salt stress. High salt Imposes negative impacts on growth, nodulation, agronomy traits, seed quality and quantity, and thus reduces the yield of soybean. To cope with salt stress, soybean has developed several tolerance mechanisms, including: (I) maintenance of ion homeostasis; (ii) adjustment in response to osmotic stress; (iii) restoration of osmotic balance; and (iv) other metabolic and structural adaptations. The regulatory network for abiotic stress responses in higher plants has been studied extensively in model plants such as Arabidopsis thaliana. Some homologous components involved in salt stress responses have been identified in soybean. In this review, we tried to integrate the relevant works on soybean and proposes a working model to descdbe Its salt stress responses at the molecular level.

  13. Salt and nephrolithiasis.

    Science.gov (United States)

    Ticinesi, Andrea; Nouvenne, Antonio; Maalouf, Naim M; Borghi, Loris; Meschi, Tiziana

    2016-01-01

    Dietary sodium chloride intake is nowadays globally known as one of the major threats for cardiovascular health. However, there is also important evidence that it may influence idiopathic calcium nephrolithiasis onset and recurrence. Higher salt intake has been associated with hypercalciuria and hypocitraturia, which are major risk factors for calcium stone formation. Dietary salt restriction can be an effective means for secondary prevention of nephrolithiasis as well. Thus in this paper, we review the complex relationship between salt and nephrolithiasis, pointing out the difference between dietary sodium and salt intake and the best methods to assess them, highlighting the main findings of epidemiologic, laboratory and intervention studies and focusing on open issues such as the role of dietary salt in secondary causes of nephrolithiasis.

  14. Waste-water impacts on groundwater: Cl/Br ratios and implications for arsenic pollution of groundwater in the Bengal Basin and Red River Basin, Vietnam.

    Science.gov (United States)

    McArthur, J M; Sikdar, P K; Hoque, M A; Ghosal, U

    2012-10-15

    Across West Bengal and Bangladesh, concentrations of Cl in much groundwater exceed the natural, upper limit of 10 mg/L. The Cl/Br mass ratios in groundwaters range up to 2500 and scatter along mixing lines between waste-water and dilute groundwater, with many falling near the mean end-member value for waste-water of 1561 at 126 mg/L Cl. Values of Cl/Br exceed the seawater ratio of 288 in uncommon NO(3)-bearing groundwaters, and in those containing measurable amounts of salt-corrected SO(4) (SO(4) corrected for marine salt). The data show that shallow groundwater tapped by tube-wells in the Bengal Basin has been widely contaminated by waste-water derived from pit latrines, septic tanks, and other methods of sanitary disposal, although reducing conditions in the aquifers have removed most evidence of NO(3) additions from these sources, and much evidence of their additions of SO(4). In groundwaters from wells in palaeo-channel settings, end-member modelling shows that >25% of wells yield water that comprises ≥10% of waste-water. In palaeo-interfluvial settings, only wells at the margins of the palaeo-interfluvial sequence contain detectable waste water. Settings are identifiable by well-colour survey, owner information, water composition, and drilling. Values of Cl/Br and faecal coliform counts are both inversely related to concentrations of pollutant As in groundwater, suggesting that waste-water contributions to groundwater in the near-field of septic-tanks and pit-latrines (within 30 m) suppress the mechanism of As-pollution and lessen the prevalence and severity of As pollution. In the far-field of such sources, organic matter in waste-water may increase groundwater pollution by As. Copyright © 2012. Published by Elsevier B.V.

  15. Source water controls on the character and origin of dissolved organic matter in streams of the Yukon River basin, Alaska

    Science.gov (United States)

    O'Donnell, Jonathan A.; Aiken, George R.; Kane, Evan S.; Jones, Jeremy B.

    2010-01-01

    Climate warming and permafrost degradation at high latitudes will likely impact watershed hydrology, and consequently, alter the concentration and character of dissolved organic carbon (DOC) in northern rivers. We examined seasonal variation of DOC chemistry in 16 streams of the Yukon River basin, Alaska. Our primary objective was to evaluate the relationship between source water (shallow versus deep groundwater flow paths) and DOC chemical composition. Using base cation chemistry and principal component analysis, we observed high contributions of deep groundwater to glacial and clearwater streams, whereas blackwater streams received larger contributions from shallow groundwater sources. DOC concentration and specific ultraviolet absorbance peaked during spring snowmelt in all streams, and were consistently higher in blackwater streams than in glacial and clearwater streams. The hydrophobic acid fraction of DOC dominated across all streams and seasons, comprising between 35% and 56% of total DOC. The hydrophilic acid fraction of DOC was more prominent in glacial (23% ± 3%) and clearwater streams (19% ± 1%) than in blackwater streams (16% ± 1%), and was enriched during winter base flow (29% ± 1%) relative to snowmelt and summer base flow. We observed that an increase in the contribution of deep groundwater to streamflow resulted in decreased DOC concentration, aromaticity, and DOC-to-dissolved organic nitrogen ratio, and an increase in the proportion of hydrophilic acids relative to hydrophobic acids. Our findings suggest that future permafrost degradation and higher contributions of groundwater to streamflow may result in a higher fraction of labile DOM in streams of the Yukon basin.

  16. Salt-Water Transport in Unsaturated Soils Under Crop Planting: Dynamics and Numerical Simulation

    Institute of Scientific and Technical Information of China (English)

    XU Li-Gang; YANG Jing-Song; ZHANG Qi; LIU Guang-Ming

    2005-01-01

    A laboratory salt-water dynamics experiment using unsaturated soils in packed silt loam and clay soil columns with different soil texture profiles and groundwater levels under crops were conducted to study the changes of salt-water dynamics induced by water uptake of crops and to propose the theoretical basis for the regulation and control of saltwater dynamics as well as to predict salinity levels. The HYDRUS 1D model was applied to simulate the one-dimensional movement of water and salt transport in the soil columns. The results showed that the salts mainly accumulated in the plow layer in the soil columns under crops. Soil water and salt both moved towards the plow layer due to soil water absorption by the crop root system. The salt contents in the column with lower groundwater were mostly greater than those with high groundwater. The water contents in the soil columns increased from top to the bottom due to plant root water uptake. The changes in groundwater level had little influence on water content of the root zone in the soil columns with crop planting. Comparison between the simulated and the determined values showed that model simulation results were ideal, so it is practicable to do numerical simulation of soil salt and water transport by the HYDRUS 1D model.Furthermore, if the actual movement of salt and water in fields is to be described in detail, much work needs to be done.The most important thing is to refine the parameters and select precise boundary conditions.

  17. Using polymer mats to biodegrade atrazine in groundwater: laboratory column experiments

    Science.gov (United States)

    Patterson, B. M.; Franzmann, P. D.; Davis, G. B.; Elbers, J.; Zappia, L. R.

    2002-02-01

    Large-scale column experiments were undertaken to evaluate the potential of in situ polymer mats to deliver oxygen into groundwater to induce biodegradation of the pesticides atrazine, terbutryn and fenamiphos contaminating groundwater in Perth, Western Australia. The polymer mats, composed of woven silicone (dimethylsiloxane) tubes and purged with air, were installed in 2-m-long flow-through soil columns. The polymer mats proved efficient in delivering dissolved oxygen to anaerobic groundwater. Dissolved oxygen concentrations increased from biodegradation rates, suggesting that organic carbon was not limiting biodegradation. Atrazine degradation rates estimated in the column experiments were similar to rates determined in laboratory culture experiments, using pure cultures of atrazine-mineralising bacteria. No significant degradation of terbutryn or fenamiphos was observed under the experimental conditions within the time frames of the study. Results from these experiments indicate that remediation of atrazine in a contaminated aquifer may be achievable by delivery of oxygen using an in situ polymer mat system.

  18. Dissolved Organic Matter in Freshwaters

    Science.gov (United States)

    Perdue, E. M.; Ritchie, J. D.

    2003-12-01

    Organic matter in freshwaters exists as dissolved molecules, colloids, and particles. It is appropriate to regard these distinctions as dynamic, however, because organic matter can be interconverted readily between these forms by dissolution and precipitation, sorption and desorption, aggregation and disaggregation, etc. Dissolved organic matter (DOM), the subject of this chapter, is defined operationally as the fraction of organic matter in a water sample that passes through a 0.45 μm filter. In the authors' opinion, the scientific literature on organic matter in freshwaters will be better reflected in this review, if data are considered without regard to the manner in which water samples may have been filtered. This more general approach is warranted because: * many submicron colloids and some microorganisms can pass through 0.45 μm filters; * the effective pore size of a 0.45 μm filter is usually unknown, because it is decreased by partial clogging during the filtration of a water sample; * some important studies have been conducted on unfiltered samples or on samples that were filtered through other types of filters; and * some important studies have been conducted on samples that were concentrated with ultrafiltration (UF), nanofiltration (NF), or reverse osmosis (RO) membranes.As methods for fractionation and isolation of organic matter in freshwaters have evolved, and as the intensity of research has waxed and waned in various academic disciplines, a rich and potentially confusing nomenclature has evolved for organic matter in freshwaters. Some of the more commonly encountered descriptors and their associated acronyms, if any, are yellow organic acids (YOAs), aquatic humus, DOM, and natural organic matter (NOM). Regardless of the terminology used in the original literature, the organic matter in freshwaters is referred to as DOM in this review, except when it is necessary to be more specific.

  19. Limits to Global Groundwater Consumption

    Science.gov (United States)

    Graaf, I. D.; Van Beek, R.; Sutanudjaja, E.; Wada, Y.; Bierkens, M. F.

    2015-12-01

    In regions with frequent water stress and large aquifer systems, groundwater is often used as an additional fresh water source. For many regions of the world groundwater abstraction exceeds groundwater recharge and persistent groundwater depletion occurs. The most direct effect of groundwater depletion is declining of water tables, leading to reduced groundwater discharge needed to sustain base-flow to e.g. rivers. Next to that, pumping costs increase, wells dry up and land subsidence occurs. These problems are expected to increase in the near future due to growing population and climate changes. This poses the urgent question of what the limits are of groundwater consumption worldwide. We simulate global water availability (5 arc-minute resolution, for 1960-2050) using the hydrological model PCR-GLOBWB (van Beek et al. 2011), coupled to a groundwater model based on MODFLOW (de Graaf et al. 2015), allowing for groundwater - surface water interactions. The groundwater model includes a parameterization of world's confined and unconfined aquifer systems needed for a realistic simulation of groundwater head dynamics. Water demands are included (from Wada et al. 2014). We study the limits to water consumption, focusing on locally attainable groundwater and groundwater levels critical to rivers to sustain low flows. We show an increasing trend (1960-2050) in groundwater head declines, due to increase in groundwater demand. Also, stream flow will decrease and low flow conditions will occur more frequent and will be longer in duration in the near future, especially for irrigated areas. Next to that, we provide a global overview of the years it takes until groundwater gets unattainable for e.g. a local farmer (100 m below land-surface used as a proxy), and estimate the increase in pumping cost for the near future. The results show where and when limits of groundwater consumption are reached globally.

  20. Hydrogeologic Processes Impacting Storage, Fate, and Transport of Chloride from Road Salt in Urban Riparian Aquifers.

    Science.gov (United States)

    Ledford, Sarah H; Lautz, Laura K; Stella, John C

    2016-05-17

    Detrimental effects of road salt runoff on urban streams are compounded by its facilitated routing via storm drains, ditches, and flood channels. Elevated in-stream salinity may also result from seasonal storage and discharge of chloride in groundwater, and previous work has hypothesized that groundwater discharge to streams may have the effect of diluting stream chloride concentrations in winter and enriching them in summer. However, the hydrogeological processes controlling these patterns have not been thoroughly investigated. Our research focuses on an urban stream and floodplain system in Syracuse, NY, to understand how groundwater and surface water exchange impacts chloride storage, fate, and transport. We created a 3D groundwater flow and solute transport model of the floodplain, calibrated to the distributions of floodplain hydraulic heads and groundwater fluxes to the stream throughout the reach. We used a sensitivity analysis to calibrate and evaluate the influence of model parameters, and compared model outputs to field observations. The main source mechanism of chloride to the floodplain aquifer was high-concentration, overbank flood events in winter that directly recharged groundwater. The modeled residence time and storage capacity of the aquifer indicate that restoration projects designed to promote floodplain reconnection and the frequency of overbank flooding in winter have the potential to temporarily store chloride in groundwater, buffer surface water concentrations, and reduce stream concentrations following periods of road salting.

  1. Dependence of Expansion of a Salt-Saturated Concrete on Temperature and Mixing and Handling Procedures.

    Science.gov (United States)

    1987-07-01

    concrete included: (1) compatibility with the host rock salt, such that it would bond to the rock rather than dissolving it; (2) a slump of more than 203...they were demolded and coated in beeswax twice, with foil between, to minimize gain or loss of moisture, and stored at laboratory ambient...concrete is placed, on or near the surface of the earth, the concrete would break down quickly. Chloride-containing components would be dissolved , altered

  2. Groundwater chemistry of a nuclear waste reposoitory in granite bedrock

    Energy Technology Data Exchange (ETDEWEB)

    Rydberg, J.

    1981-09-01

    This report concerns the prediction of the maximum dissolution rate for nuclear waste stored in the ground. That information is essential in judging the safety of a nuclear waste repository. With a limited groundwater flow, the maximum dissolution rate coincides with the maximum solubility. After considering the formation and composition of deep granite bedrock groundwater, the report discusses the maximum solubility in such groundwater of canister materials, matrix materials and waste elements. The parameters considered are pH, Eh and complex formation. The use of potential-pH (Pourbaix) diagrams is stressed; several appendixes are included to help in analyzing such diagrams. It is repeatedly found that desirable basic information on solution chemistry is lacking, and an international cooperative research effort is recommended. The report particularly stresses the lack of reliable data about complex formation and hydrolysis of the actinides. The Swedish Nuclear Fuel Safety (KBS) study has been used as a reference model. Notwithstanding the lack of reliable chemical data, particularly for the actinides and some fission products, a number of essential conclusions can be drawn about the waste handling model chosen by KBS. (1) Copper seems to be highly resistant to groundwater corrosion. (2) Lead and titanium are also resistant to groundwater, but inferior to copper. (3) Iron is not a suitable canister material. (4) Alumina (Al/sub 2/O/sub 3/) is not a suitable canister material if groundwater pH goes up to or above 10. Alumina is superior to copper at pH < 9, if there is a risk of the groundwater becoming oxidizing. (5) The addition of vivianite (ferrous phosphate) to the clay backfill around the waste canisters improves the corrosion resistance of the metal canisters, and reduces the solubility of many important waste elements. This report does not treat the migration of dissolved species through the rock.

  3. The soil organic carbon content of anthropogenically altered organic soils effects the dissolved organic matter quality, but not the dissolved organic carbon concentrations

    Science.gov (United States)

    Frank, Stefan; Tiemeyer, Bärbel; Bechtold, Michel; Lücke, Andreas; Bol, Roland

    2016-04-01

    Dissolved organic carbon (DOC) is an important link between terrestrial and aquatic ecosystems. This is especially true for peatlands which usually show high concentrations of DOC due to the high stocks of soil organic carbon (SOC). Most previous studies found that DOC concentrations in the soil solution depend on the SOC content. Thus, one would expect low DOC concentrations in peatlands which have anthropogenically been altered by mixing with sand. Here, we want to show the effect of SOC and groundwater level on the quantity and quality of the dissolved organic matter (DOM). Three sampling sites were installed in a strongly disturbed bog. Two sites differ in SOC (Site A: 48%, Site B: 9%) but show the same mean annual groundwater level of 15 and 18 cm below ground, respectively. The SOC content of site C (11%) is similar to Site B, but the groundwater level is much lower (-31 cm) than at the other two sites. All sites have a similar depth of the organic horizon (30 cm) and the same land-use (low-intensity sheep grazing). Over two years, the soil solution was sampled bi-weekly in three depths (15, 30 and 60 cm) and three replicates. All samples were analyzed for DOC and selected samples for dissolved organic nitrogen (DON) and delta-13C and delta-15N. Despite differences in SOC and groundwater level, DOC concentrations did not differ significantly (A: 192 ± 62 mg/L, B: 163 ± 55 mg/L and C: 191 ± 97 mg/L). At all sites, DOC concentrations exceed typical values for peatlands by far and emphasize the relevance even of strongly disturbed organic soils for DOC losses. Individual DOC concentrations were controlled by the temperature and the groundwater level over the preceding weeks. Differences in DOM quality were clearer. At site B with a low SOC content, the DOC:DON ratio of the soil solution equals the soil's C:N ratio, but the DOC:DON ratio is much higher than the C:N ratio at site A. In all cases, the DOC:DON ratio strongly correlates with delta-13C. There is no

  4. Hydrologic and nutrient response of groundwater to flooding of cranberry farms in southeastern Massachusetts, USA

    Science.gov (United States)

    Kennedy, Casey D.

    2015-06-01

    Seasonal flooding of cranberry farms is essential for commercial production of cranberries in southeastern Massachusetts, with close to 90% of growers using a flood for harvesting and winter protection. Although periodic flooding results in increased groundwater recharge, it may also exacerbate subsurface transport of dissolved forms of nitrogen and phosphorus. Given the paucity of information on groundwater exchange with cranberry floodwaters, hydrometric measurements were used to solve for the residual term of groundwater recharge in water budgets for three cranberry farms during the harvest and winter floods. Combined with continuous monitoring of water-table depth and discrete sampling of groundwater for analysis of nitrate (NO3-), ammonium (NH4+), and total dissolved phosphorus (TDP), values of groundwater recharge were used to evaluate the hydrologic and nutrient response of groundwater to flooding of cranberry farms. Mean values of groundwater recharge were 11 (±6) and 47 (±11) cm for the harvest and winter floods, respectively (one standard deviation in parentheses). The factor-of-four difference in ground recharge was related to flood holding times that, on average, were twenty days longer for the winter flood. The total estimated seasonal groundwater recharge of 58 cm was about four times higher than that assigned to cranberry farms in regional groundwater flow models. During the floods, 10 to 20-cm increases in water-table depth were observed for wells within 10 m of the farm, contrasting with decreases (or minimal variation) in water-table depth for wells located 100 m or farther from the farm. These spatial patterns in the hydrologic response of groundwater suggested a zone of influence of approximately 100 m from the flooded edge of the farm. Analysis of 43 groundwater samples collected from 10 wells indicated generally low concentrations of TDP in groundwater (edge of farms). For one groundwater well located in proximity to the farm (∼10 m

  5. The role of dissolved cations in coffee extraction.

    Science.gov (United States)

    Hendon, Christopher H; Colonna-Dashwood, Lesley; Colonna-Dashwood, Maxwell

    2014-05-28

    The flavorsome compounds in coffee beans exist in the form of aprotic charge neutral species, as well as a collection of acids and conjugate salts. The dissolution and extraction of these organic molecules is a process dependent on the dissolved mineral content of the water. It is known that different rates and compositions of coffee extraction are achieved through the control of the water "impurities", Na(+), Mg(2+), and Ca(2+), which coordinate to nucleophilic motifs in coffee. Using density functional theory, we quantify the thermodynamic binding energies of five familiar coffee-contained acids, caffeine, and a representative flavor component, eugenol. From this, we provide insight into the mechanism and ideal mineral composition of water for extraction of flavorsome compounds in coffee.

  6. Groundwater: Quality Levels and Human Exposure, SW Nigeria

    Directory of Open Access Journals (Sweden)

    Olusola Adeyemi

    2017-04-01

    Full Text Available Groundwater serves as a source of freshwater for agricultural, industrial and domestic purposes and it accounts for about 42%, 27% and 36% respectively. As it remains the only source of all-year-round supply of freshwater globally, it is of vital importance as regards water security, human survival and sustainable agriculture. The main goal of this study is to identify the main cause-effect relationship between human activities and the state of groundwater quality using a communication tool (the DPSIR Model; Drivers, Pressures, State, Impact and Response. A total of twenty-one samples were collected from ten peri-urban communities scattered across three conterminous Local Government Areas in Southwestern Nigeria. Each of the groundwater samples was tested for twelve parameters - total dissolved solids, pH, bicarbonate, chloride, lead, electrical conductivity, dissolved oxygen, nitrate, sulphate, magnesium and total suspended solids. The study revealed that the concentrations of DO and Pb were above threshold limits, while pH and N were just below the threshold and others elements were within acceptable limits based on Guidelines for Drinking Water Quality and Nigeria Standard for Drinking Water Quality. The study revealed that groundwater quality levels from the sampled wells are under pressure leading to reduction in the amount of freshwater availability. This is a first-order setback in achieving access to freshwater as a sustainable development goal across Less Developed Communities (LDCs globally. To combat this threat, there is the need for an integrated approach in response towards groundwater conservation and sustainability by all stakeholders.

  7. DS796 California Groundwater Units

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The California Groundwater Units dataset classifies and delineates the State into one of three groundwater based polygon units: (1) those areas defined as alluvial...

  8. Behaviour of boron and strontium isotopes in groundwater-aquifer interactions in the Cornia Plain (Tuscany, Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Pennisi, Maddalena [Istituto di Geoscienze e Georisorse, CNR, Pisa (Italy)]. E-mail: M.Pennisi@igg.cnr.it; Bianchini, Gianluca [Istituto di Geoscienze e Georisorse, CNR, Pisa (Italy); Dipartimento di Scienze della Terra, Universita di Ferrara (Italy); Muti, Antonio [Azienda Servizi Ambientali, Area Val di Cornia, Livorno (Italy); Kloppmann, Wolfram [Bureau des Recherches Geologiques et Minieres, Orleans (France); Gonfiantini, Roberto [Istituto di Geoscienze e Georisorse, CNR, Pisa (Italy)

    2006-07-15

    The Cornia Plain alluvial aquifer, in Tuscany, is exploited intensely to meet the demand for domestic, irrigation and industrial water supplies. The B concentration of groundwater, however, is often above the European limit of 1 mg L{sup -1}, with the result that exploitation of these water resources requires careful management. Boron and Sr isotopes have been used as part of a study on the origin and distribution of B dissolved in groundwater, and indirectly as a contribution to the development of appropriate water management strategies. The geochemistry of the Cornia Plain groundwater changes from a HCO{sub 3} facies in the inland areas to a Cl facies along the coastal belt, where seawater intrusion takes place. The B concentration of groundwater increases towards the coastal areas, while the {sup 11}B/{sup 10}B ratio decreases. This indicates that there is an increasing interaction between dissolved B and the sediments forming the aquifer matrix, whose B content is in the order of 100 mg kg{sup -1}. Adsorption-desorption exchanges take place between water and the sediment fine fraction rich in clay minerals, with a net release of B from the matrix into the groundwater, and a consequent {delta} {sup 11}B shift from positive to negative values. The aquifer matrix sediments therefore seem to be the major source of B dissolved in the groundwater. The groundwater-matrix interactions triggered by the ionic strength increase caused by seawater intrusion can also be detected in the Ca-Na ion exchanges. Dissolved Sr follows a trend similar to that of Ca, while the {sup 87}Sr/{sup 86}Sr ratio is equal to that of the exchangeable Sr of the aquifer matrix and therefore does not change significantly. These results have helped to define a new strategy for groundwater exploitation, with the final objective of reducing B concentration in the water extracted from the aquifer.

  9. Crushed Salt Constitutive Model

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, G.D.

    1999-02-01

    The constitutive model used to describe the deformation of crushed salt is presented in this report. Two mechanisms -- dislocation creep and grain boundary diffusional pressure solution -- are combined to form the basis for the constitutive model governing the deformation of crushed salt. The constitutive model is generalized to represent three-dimensional states of stress. Upon complete consolidation, the crushed-salt model reproduces the Multimechanism Deformation (M-D) model typically used for the Waste Isolation Pilot Plant (WIPP) host geological formation salt. New shear consolidation tests are combined with an existing database that includes hydrostatic consolidation and shear consolidation tests conducted on WIPP and southeastern New Mexico salt. Nonlinear least-squares model fitting to the database produced two sets of material parameter values for the model -- one for the shear consolidation tests and one for a combination of the shear and hydrostatic consolidation tests. Using the parameter values determined from the fitted database, the constitutive model is validated against constant strain-rate tests. Shaft seal problems are analyzed to demonstrate model-predicted consolidation of the shaft seal crushed-salt component. Based on the fitting statistics, the ability of the model to predict the test data, and the ability of the model to predict load paths and test data outside of the fitted database, the model appears to capture the creep consolidation behavior of crushed salt reasonably well.

  10. Hydro-chemical assessment and groundwater recharge mechanism in the humid tropics: a case study.

    Science.gov (United States)

    Hameed, A Shahul; Prasad, N B Narasimha

    2008-10-01

    The study related to assessment of various chemical constituents in the groundwater, their origin and suitability for human use has been carried out in the Chaliyar river basin of Kerala (India). Groundwater samples were collected from 27 open dug wells and 7 bore wells, and analyzed. Piper tri-linear classification was followed in segregating the data with respect to source of dissolved constituents in groundwater. Most of the wells fall within the no dominant ion zone in the piper diagram, indicating the equal distribution of alkalis and alkaline earths. High level of dissolved solids, with the presence of chloride and sulphate, was observed in a few wells in the coastal region, which may be due to the salinity intrusion from the sea. The groundwater quality was found fairly good and potable in the lateritic midland region, except for a few wells, which were having significant level of nitrate and/or chloride. An attempt has been made to understand the source of groundwater recharge in the basin using environmental tritium as a tracer. It has been observed that the groundwater is predominantly recharged through rainfall, as evidenced from the level of tritium close to that of local precipitation.

  11. Environmental impact of municipal dumpsite leachate on ground-water quality in Jawaharnagar, Rangareddy, Telangana, India

    Science.gov (United States)

    Soujanya Kamble, B.; Saxena, Praveen Raj

    2016-10-01

    The aim of the present work was to study the impact of dumpsite leachate on ground-water quality of Jawaharnagar village. Leachate and ground-water samples were investigated for various physico-chemical parameters viz., pH, total dissolved solids (TDS), total hardness (TH), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), chloride (Cl-), carbonates (CO3 2-), bicarbonates (HCO3 -), nitrates (NO3 -), and sulphates (SO4 2-) during dry and wet seasons in 2015 and were reported. The groundwater was hard to very hard in nature, and the concentrations of total dissolved solids, chlorides, and nitrates were found to be exceeding the permissible levels of WHO drinking water quality standards. Piper plots revealed that the dominant hydrochemical facies of the groundwater were of calcium chloride (CaCl2) type and alkaline earths (Ca2+ and Mg2+) exceed the alkali (Na+ and SO4 2-), while the strong acids (Cl- and SO4 2-) exceed the weak acids (CO3 2- and HCO3 -). According to USSL diagram, all the ground-water samples belong to high salinity and low-sodium type (C3S1). Overall, the ground-water samples collected around the dumpsite were found to be polluted and are unfit for human consumption but can be used for irrigation purpose with heavy drainage and irrigation patterns to control the salinity.

  12. Hanford Site ground-water monitoring for July through December 1987

    Energy Technology Data Exchange (ETDEWEB)

    Evans, J.C.; Dennison, D.I.; Bryce, R.W.; Mitchell, P.J.; Sherwood, D.R.; Krupka, K.M.; Hinman, N.W.; Jacobson, E.A.; Freshley, M.D.

    1988-12-01

    The Pacific Northwest Laboratory monitors ground-water quality at the Hanford Site for the US Department of Energy to assess the impact of Site operations on the environment. Work undertaken between July and December 1987 included monitoring ground-water elevations across the Site, monitoring hazardous chemicals and radionuclides in ground water, geochemical evaluations of unconfined ground-water data, and calibration of ground-water flow and transport models. Water levels continued to rise in areas receiving increased recharge (e.g., beneath B Pond) and decline in areas where the release of water to disposal facilities has been terminated (e.g., U Pond). The major areas of ground-water contamination defined by monitoring activities are (1) carbon tetrachloride in the 200-West Area; (2) cyanide in and north of the 200-East and 200-West Areas; (3) hexavalent chromium contamination in the 100-B, 100-D, 100-F, 100-H, 100-K, and 200-West Areas; (4) chlorinated hydrocarbons in the vicinity of the Central Landfill and 300 Area; (5) uranium in the 100-F, 100-H, 200-West, and 300 Areas; and (6) tritium and nitrate across the Site. The MINTEQ geochemical code was used to identify chemical reactions that may be affecting the concentrations of dissolved hazardous chemicals in the unconfined ground water. Results indicate that many cations are present mainly as dissolved carbonate complexes and that a majority of the ground-water samples are in near equilibrium with carbonate minerals (e.g., calcite, dolomite, otavite).

  13. Groundwater circulation and hydrogeochemical evolution in Nomhon of Qaidam Basin, northwest China

    Indian Academy of Sciences (India)

    Yong Xiao; Jingli Shao; Yali Cui; Ge Zhang; Qiulan Zhang

    2017-03-01

    In this study, analysis of hydrogeological conditions, as well as hydrochemistry and isotopic tools were used to get an insight into the processes controlling mineralization, recharge conditions, and flow pattern of groundwater in a typical arid alluvial-lacustrine plain in Qaidam Basin, northwest China. Analysisof the dissolved constituents reveals that groundwater evolves from fresh water (TDS=300–1000 mg/l) to saline water (TDS ≥5000 mg/l) along the flow paths, with the water type transiting from HCO ₃•Cl– Na•Mg to HCO ₃•Cl–Na, and eventually to Cl–Na. Groundwater chemical evolution is mainly controlled by water–rock interaction and the evaporation–crystallization process. Deuterium and oxygen-18 isotopes in groundwater samples indicate that the recharge of groundwater is happened by meteoric water andglacier melt-water in the Kunlun Mountains, and in three different recharge conditions. Groundwater ages, estimated by the radiogenic (³H and ¹⁴C) isotope data, range from present to Holocene (~28ka). Based on groundwater residence time, hydrogeochemical characteristics, field investigation, and geological structure distribution, a conceptual groundwater flow pattern affected by uplift structure is proposed, indicating that shallow phreatic water is blocked by the uplift structure and the flow directionis turned to the northwest, while high pressure artesian water is formed in the confined aquifers at the axis of the uplift structure.

  14. Gases in molten salts

    CERN Document Server

    Tomkins, RPT

    1991-01-01

    This volume contains tabulated collections and critical evaluations of original data for the solubility of gases in molten salts, gathered from chemical literature through to the end of 1989. Within the volume, material is arranged according to the individual gas. The gases include hydrogen halides, inert gases, oxygen, nitrogen, hydrogen, carbon dioxide, water vapor and halogens. The molten salts consist of single salts, binary mixtures and multicomponent systems. Included also, is a special section on the solubility of gases in molten silicate systems, focussing on slags and fluxes.

  15. Status and understanding of groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units, 2006-2007--California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    , and molybdenum) were 41% high, 36% moderate, and 23% low. In the Southern Sierra study unit, 32, 34, and 34% of the primary aquifer had high, moderate, and low RCs of inorganic constituents with health-based benchmarks (primarily arsenic, uranium, fluoride, boron, and nitrate). The high aquifer-scale proportions for inorganic constituents with non-health-based benchmarks were 14, 34, and 24% for the Tahoe-Martis, Central Sierra, and Southern Sierra study units, respectively, and the primary constituent was manganese for all three study units. Organic constituents with health-based benchmarks were not present at high RCs in the primary aquifers of the Central Sierra and Southern Sierra study units, and were present at high RCs in only 1% of the Tahoe-Martis study unit. Moderate aquifer-scale proportions for organic constituents were 10%: the trihalomethane chloroform in the Tahoe-Martis study unit; chloroform and the herbicide simazine in the Central Sierra study unit; and chloroform, simazine, the herbicide atrazine, and the solvent perchloroethene in the Southern Sierra study unit. The second component of this study, the understanding assessment, identified the natural and human factors that may have affected groundwater quality in the three study units by evaluating statistical correlations between water-quality constituents and potential explanatory factors. The potential explanatory factors evaluated were land use, septic tank density, climate, relative position in the regional flow system, aquifer lithology, geographic location, well depth and depth to the top of the screened or open interval in the well, groundwater age distribution, pH, and dissolved oxygen concentration. Results of the statistical evaluations were used to explain the occurrence and distribution of constituents in the study units. Aquifer lithology (granitic, metamorphic, sedimentary, or volcanic rocks), groundwater age distribution [modern (recharged since 1952), pre-modern (recharged before

  16. In situ groundwater bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Hazen, Terry C.

    2009-02-01

    In situ groundwater bioremediation of hydrocarbons has been used for more than 40 years. Most strategies involve biostimulation; however, recently bioaugmentation have been used for dehalorespiration. Aquifer and contaminant profiles are critical to determining the feasibility and strategy for in situ groundwater bioremediation. Hydraulic conductivity and redox conditions, including concentrations of terminal electron acceptors are critical to determine the feasibility and strategy for potential bioremediation applications. Conceptual models followed by characterization and subsequent numerical models are critical for efficient and cost effective bioremediation. Critical research needs in this area include better modeling and integration of remediation strategies with natural attenuation.

  17. Saline Groundwater from Coastal Aquifers As a Source for Desalination.

    Science.gov (United States)

    Stein, Shaked; Russak, Amos; Sivan, Orit; Yechieli, Yoseph; Rahav, Eyal; Oren, Yoram; Kasher, Roni

    2016-02-16

    Reverse osmosis (RO) seawater desalination is currently a widespread means of closing the gap between supply and demand for potable water in arid regions. Currently, one of the main setbacks of RO operation is fouling, which hinders membrane performance and induces pressure loss, thereby reducing system efficiency. An alternative water source is saline groundwater with salinity close to seawater, pumped from beach wells in coastal aquifers which penetrate beneath the freshwater-seawater interface. In this research, we studied the potential use of saline groundwater of the coastal aquifer as feedwater for desalination in comparison to seawater using fieldwork and laboratory approaches. The chemistry, microbiology and physical properties of saline groundwater were characterized and compared with seawater. Additionally, reverse osmosis desalination experiments in a cross-flow system were performed, evaluating the permeate flux, salt rejection and fouling propensities of the different water types. Our results indicated that saline groundwater was significantly favored over seawater as a feed source in terms of chemical composition, microorganism content, silt density, and fouling potential, and exhibited better desalination performance with less flux decline. Saline groundwater may be a better water source for desalination by RO due to lower fouling potential, and reduced pretreatment costs.

  18. Biogeochemistry of dissolved organic matter in an anoxic intertidal creek bank

    Science.gov (United States)

    Seidel, Michael; Beck, Melanie; Riedel, Thomas; Waska, Hannelore; Suryaputra, I. G. N. A.; Schnetger, Bernhard; Niggemann, Jutta; Simon, Meinhard; Dittmar, Thorsten

    2014-09-01

    Seawater circulation in permeable coastal sediments is driven by tidal changes in hydraulic gradients. The resulting submarine groundwater discharge is a source of nutrients and dissolved organic matter (DOM) to the water column. Yet, little is known about the cycling of DOM within tidal sediments, because the molecular DOM characterization remains analytically challenging. One technique that can dissect the multitude of molecules in DOM is ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). To aim at a high resolution DOM analysis we study the seasonal turnover and marine and terrestrial sources of DOM in an intertidal creek bank of the southern North Sea down to 3 m depth and link the biogeochemical processes to FT-ICR-MS data and the analyses of inorganic porewater chemistry, δ13C of solid-phase extracted dissolved organic carbon (SPE-DOC), dissolved black carbon (DBC) and dissolved carbohydrates (DCHO). Increasing concentrations of dissolved Fe, Mn, P, total alkalinity, dissolved nitrogen, DOC and a concomitant decrease of sulfate along the seawater circulation path from the upper tidal flat to the tidal flat margin indicate continuous microbial activity. The relative increase of Si concentrations, unsaturated aliphatics, peptide molecular formulae and isotopically more 13C-enriched SPE-DOC towards the tidal flat margin suggests that remineralization processes mobilize DOM from buried algal (diatoms) and microbial biomass. Porewater in sediments ocean. Porewater DOM accumulating at the low water line is enriched in N and S. We hypothesize that this is partly due to DOM reacting with dissolved sulfide and ammonium which may increase the refractory character of the DOM, hence making it less bioavailable for in situ active microbes.

  19. Groundwater: A Community Action Guide.

    Science.gov (United States)

    Boyd, Susan, Ed.; And Others

    Designed to be a guide for community action, this booklet examines issues and trends related to groundwater contamination. Basic concepts about groundwater and information about problems affecting it are covered under the categories of (1) what is groundwater? (2) availability and depletion; (3) quality and contamination; (4) public health…

  20. Groundwater: A Community Action Guide.

    Science.gov (United States)

    Boyd, Susan, Ed.; And Others

    Designed to be a guide for community action, this booklet examines issues and trends related to groundwater contamination. Basic concepts about groundwater and information about problems affecting it are covered under the categories of (1) what is groundwater? (2) availability and depletion; (3) quality and contamination; (4) public health…

  1. Characterization of TCE DNAPL and Dissolved Phase Transport in Karst Media

    Science.gov (United States)

    Carmona, M.; Padilla, I. Y.

    2015-12-01

    Trichloroethylene (TCE) contaminated sites are a threat to the environment and human health. Of particular concerns is the contamination of karst groundwater systems (KGWSs). Their heterogeneous character, rapid flow through conduits, high permeability zones, and strong storage capacity in the rock porous-matrix pose a high risk of exposure over large areas and temporal scales. To achieve effective remedial actions for TCE removal, it is important to understand and quantify the fate and transport process of trichloroethylene in these systems. This research studies the fate, transport, and distribution of TCE Non-Aqueous Phase Liquids (NAPLs) and associated dissolved species in KGWSs. Experiments are conducted in a karstified limestone physical model, a limestone rock mimicking a saturated confined karst aquifer. After injecting TCE solvent into a steady groundwater flow field, samples are taken spatially and temporally and analyzed for TCE NAPL and dissolved phases. Data analysis shows the rapid detection of TCE NAPL and high aqueous concentrations along preferential pathway, even at distances far away from the injection point. Temporal distribution curves exhibit spatial variations related to the limestone rock heterogeneity. Rapid response to TCE concentrations is associated with preferential flow paths. Slow response with long tailing indicates rate-limited diffusive transport in the rock matrix. Overall, results indicate that karstified limestone has a high capacity to rapidly transport pure and dissolved TCE along preferential flow paths, and to store and slowly release TCE over long periods of time.

  2. High-pressure injection of dissolved oxygen for hydrocarbon remediation in a fractured dolostone aquifer

    Science.gov (United States)

    Greer, K. D.; Molson, J. W.; Barker, J. F.; Thomson, N. R.; Donaldson, C. R.

    2010-10-01

    A field experiment was completed at a fractured dolomite aquifer in southwestern Ontario, Canada, to assess the delivery of supersaturated dissolved oxygen (supersaturated with respect to ambient conditions) for enhanced bioremediation of petroleum hydrocarbons in groundwater. The injection lasted for 1.5 h using iTi's gPro® oxygen injection technology at pressures of up to 450 kPa and at concentrations of up to 34 mg O 2/L. A three-dimensional numerical model for advective-dispersive transport of dissolved oxygen within a discretely-fractured porous medium was calibrated to the observed field conditions under a conservative (no-consumption) scenario. The simulation demonstrated that oxygen rapidly filled the local intersecting fractures as well as the porous matrix surrounding the injection well. Following injection, the local fractures were rapidly flushed by the natural groundwater flow system but slow back-diffusion ensured a relatively longer residence time in the matrix. A sensitivity analysis showed significant changes in behaviour with varying fracture apertures and hydraulic gradients. Applying the calibrated model to a 7-day continuous injection scenario showed oxygen residence times (at the 3 mg/L limit), within a radius of 2-4 m from the injection well, of up to 100 days. This study has demonstrated that supersaturated dissolved oxygen can be effectively delivered to this type of a fractured and porous bedrock system at concentrations and residence times potentially sufficient for enhanced aerobic biodegradation.

  3. Shallow groundwater nitrogen responses to different land use managements in the riparian zone of Yuqiao Reservoir in North China

    Institute of Scientific and Technical Information of China (English)

    LU Haiming; YIN Chengqing

    2008-01-01

    This field study investigated the nitrogen concentrations in the shallow groundwater from an ephemeral stream and four land uses:cropland,two-year restored (2yr) and five-years restored (5yr) woodlands,fishponds,and the nitrogen flux in the riparian zone of Yuqiao Reservoir.The groundwater nitrate-N concentrations in cropland were the highest among the four land uses.Total dissolved nitrogen (TDN) and nitrate-N concentrations in the 2yr woodland were significantly (p<0.05) higher than in 5yr woodland.The lowest nitrogen concentrations were detected in fishponds.Nitrate-N was the main form in cropland and 2yr woodland,whereas both nitrate-N and diSSolved organic nitrogen (DON) were the main species in 5yr woodland and fishponds.But,ammonium-N was the main form in the ephemeral stream.During the rainy season,the groundwater flow wim dissolved nitrogen drains from upland into the reservoir along the hydraulic gradient.The woodland between the cropland and reservoir could act as a buffer to retain shallow groundwater nitrogen.The dominant form of ammonium-N in the groundwater TDN pool in ephemeral stream indicated that nitrogen from the village and orchard in upland flowed into the reservoir via subsurface flow.The fishpond Was not an important pollution source for nitrogen transfer via shallow groundwater.

  4. Nearshore morphology, benthic structure, hydrodynamics, and coastal groundwater discharge near Kahekili Beach Park, Maui, Hawaii

    Science.gov (United States)

    Swarzenski, Peter W.; Storlazzi, Curt D.; Presto, M. Katherine; Gibbs, Ann E.; Smith, Christopher G.; Dimova, Natasha T.; Dailer, Meghan L.; Logan, Joshua B.

    2012-01-01

    This report presents a brief summary of recent fieldwork conducted off Kahekili Beach Park, Maui, Hawaii, the site of the newly established U.S. Coral Reef Task Force priority study area at Kaanapali and the Hawaii Department of Land and Natural Resources, Division of Aquatic Resources, Kahekili Herbivore Fisheries Management Area (HFMA). The goals of this fieldwork are to provide new baseline information to help guide future studies and to provide first insights into rates and drivers of coastal groundwater discharge and associated constituent loadings into the priority study area's coastal waters. This study presents the first swath acoustic mapping information, in situ oceanographic instrument measurements, and coastal groundwater discharge estimates at this site based on the submarine groundwater discharge tracer radon-222 (222Rn). Coastal groundwater discharge rates ranged from about 22 to 50 centimeters per day, depending on proximity of the sampling mooring to the primary discharge vent. The water chemistry of the discharging groundwater was at times dramatically different than ambient seawater. For example, at the primary vent site at Kahekili, the concentrations of total dissolved nitrogen (TDN), dissolved silicate (DSi), and total dissolved phosphorus (TDP) in the discharging groundwater were 43.75 micromolar (μM), 583.49 μM, and 12.04 μM, respectively. These data extend our basic understanding of the morphology, benthic structure, and oceanographic setting of this vent site and provide a first estimate of the magnitude and physical forcings of submarine groundwater discharge and associated trace metals and nutrient loads here.

  5. MOUTH DISSOLVING FILM AND THEIR PATENT: AN OVERVIEW

    OpenAIRE

    2012-01-01

    Now days the researchers are focusing on the fast dissolving dosage form (FDDF’s).The fast dissolving dosage forms includes the mouth dissolving tablets, mouth dissolving thin films .The alternative words used for these dosage forms are fast disintegrating, orodispersible, fast dissolving. The oral thin film technology (OTF’s) is a dissolvable film technology have evolved from a purely confectionery novelty from a drug delivery platform. The OTH dosage form dissolves in the moth without nee...

  6. Dissolved carbohydrate in the central Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Dhople, V.M.; Bhosle, N.B.

    Seawater samples (161), collected from 8 depths (0 to 1000 m) at 21 stations were analysed for total dissolved carbohydrate. Dissolved carbohydrate concentrations varied from 0.072 to 1.15 mg.l-1. Carbohydrate concentrations did not decrease...

  7. Hydrogeochemical assessment of groundwater in Kashmir Valley, India

    Science.gov (United States)

    Jeelani, G. H.; Shah, Rouf Ahmad; Hussain, Aadil

    2014-06-01

    Groundwater samples ( n = 163) were collected across Kashmir Valley in 2010 to assess the hydrogeochemistry of the groundwater in shallow and deep aquifers and its suitability for domestic, agriculture, horticulture, and livestock purposes. The groundwater is generally alkaline in nature. The electrical conductivity (EC) which is an index to represent the total concentration of soluble salts in water was used to measure the salinity hazard to crops as it reflects the TDS in groundwater ranging from 97 to 1385 μS/cm, except one well in Sopore. The average concentration of major ions was higher in shallow aquifers than in deeper aquifers. In general, Ca2+ is the dominant cation and HCO the dominant anion. Ca-HCO3, Mg-HCO3, Ca-Mg-HCO3, Na-HCO3 were the dominant hydrogeochemical facies. High concentration of HCO3 and pH less than 8.8 clearly indicated that intense chemical weathering processes have taken place in the study area. The groundwater flow pattern in the area follows the local surface topography which not only modifies the hydrogeochemical facies but also controls their distribution. The groundwater in valley flows into four directions, i.e., SW-NE, NE-W, SE-NW and SE-NE directions. The results suggest that carbonate dissolution is the dominant source of major ions followed by silicate weathering and ion-exchange processes. The concentrations of all the major ions determined in the present study are within the permissible limits of WHO and BIS standards. The results of Total Hardness, SAR, Na%, Kelly Index, USDA classification, Magnesium absorption ratio, residual sodium carbonate, and PI suggested that groundwater is good for drinking, livestock, and irrigation purposes.

  8. Hydrogeochemical assessment of groundwater in Kashmir Valley, India

    Indian Academy of Sciences (India)

    G H Jeelani; Rouf Ahmad Shah; Aadil Hussain

    2014-07-01

    Groundwater samples ( = 163) were collected across Kashmir Valley in 2010 to assess the hydrogeochemistry of the groundwater in shallow and deep aquifers and its suitability for domestic, agriculture, horticulture, and livestock purposes. The groundwater is generally alkaline in nature. The electrical conductivity (EC) which is an index to represent the total concentration of soluble salts in water was used to measure the salinity hazard to crops as it reflects the TDS in groundwater ranging from 97 to 1385 S/cm, except one well in Sopore. The average concentration of major ions was higher in shallow aquifers than in deeper aquifers. In general, Ca2+ is the dominant cation and HCO$^{−}_{3}$ the dominant anion. Ca–HCO3, Mg–HCO3, Ca–Mg–HCO3, Na–HCO3 were the dominant hydrogeochemical facies. High concentration of HCO3 and pH less than 8.8 clearly indicated that intense chemical weathering processes have taken place in the study area. The groundwater flow pattern in the area follows the local surface topography which not only modifies the hydrogeochemical facies but also controls their distribution. The groundwater in valley flows into four directions, i.e., SW–NE, NE–W, SE–NW and SE–NE directions. The results suggest that carbonate dissolution is the dominant source of major ions followed by silicate weathering and ion-exchange processes. The concentrations of all the major ions determined in the present study are within the permissible limits ofWHO and BIS standards. The results of Total Hardness, SAR, Na%, Kelly Index, USDA classification, Magnesium absorption ratio, residual sodium carbonate, and PI suggested that groundwater is good for drinking, livestock, and irrigation purposes.

  9. Treatment of Organic Compounds in Reclaimed Wastewater for Groundwater Recharge

    Institute of Scientific and Technical Information of China (English)

    皮运正; 胡俊; 云桂春

    2004-01-01

    To study water quality problems associated with groundwater recharge,a tertiary treatment process,consisting of coagulation,sand filtration,and granular activated carbon (GAC) adsorption,was used in combination with a simulated soil aquifer treatment.The process significantly improved secondary effluent quality.GAC adsorption reduced organic substances expressed by UV-254,dissolved organic carbon as well as partially adsorbable organic halogens.The results of the Ames test show that the secondary effluent contains a high concentration of mutagens.GAC filtration removed adsorbable organic bromine slightly whereas GAC adsorption removed mutagens effectively.The simulated soil aquifer treatment was able to further reduce UV-254,dissolved organic carbon,and adsorbable organic halogens through biodegradation.Adsorbable organic bromine levels were also reduced by the soil aquifer treatment process.The given reclamation technology used for groundwater recharge is of benefit to the removal of dissolved organic carbon,UV-254,adsorbable organic halogens,and mutagenicity.

  10. Simulation of groundwater flow and interaction of groundwater and surface water on the Lac du Flambeau Reservation, Wisconsin

    Science.gov (United States)

    Juckem, Paul F.; Fienen, Michael N.; Hunt, Randall J.

    2014-01-01

    The Lac du Flambeau Band of Lake Superior Chippewa and Indian Health Service are interested in improving the understanding of groundwater flow and groundwater/surface-water interaction on the Lac du Flambeau Reservation (Reservation) in southwest Vilas County and southeast Iron County, Wisconsin, with particular interest in an understanding of the potential for contamination of groundwater supply wells and the fate of wastewater that is infiltrated from treatment lagoons on the Reservation. This report describes the construction, calibration, and application of a regional groundwater flow model used to simulate the shallow groundwater flow system of the Reservation and water-quality results for groundwater and surface-water samples collected near a system of waste-water-treatment lagoons. Groundwater flows through a permeable glacial aquifer that ranges in thickness from 60 to more than 200 feet (ft). Seepage and drainage lakes are common in the area and influence groundwater flow patterns on the Reservation. A two-dimensional, steady-state analytic element groundwater flow model was constructed using the program GFLOW. The model was calibrated by matching target water levels and stream base flows through the use of the parameter-estimation program, PEST. Simulated results illustrate that groundwater flow within most of the Reservation is toward the Bear River and the chain of lakes that feed the Bear River. Results of analyses of groundwater and surface-water samples collected downgradient from the wastewater infiltration lagoons show elevated levels of ammonia and dissolved phosphorus. In addition, wastewater indicator chemicals detected in three downgradient wells and a small downgradient stream indicate that infiltrated wastewater is moving southwest of the lagoons toward Moss Lake. Potential effects of extended wet and dry periods (within historical ranges) were evaluated by adjusting precipitation and groundwater recharge in the model and comparing the

  11. Positive and negative impacts of five Austrian gravel pit lakes on groundwater quality.

    Science.gov (United States)

    Muellegger, Christian; Weilhartner, Andreas; Battin, Tom J; Hofmann, Thilo

    2013-01-15

    Groundwater-fed gravel pit lakes (GPLs) affect the biological, organic, and inorganic parameters of inflowing groundwater through combined effects of bank filtration at the inflow, reactions within the lake, and bank filtration at the outflow. GPLs result from wet dredging for sand and gravel and may conflict with groundwater protection programs by removing the protective soil cover and exposing groundwater to the atmosphere. We have investigated the impact on groundwater of five GPLs with different sizes, ages, and mean residence times, and all having low post-excavation anthropogenic usage. The results revealed highly active biological systems within the lake water, in which primary producers significantly reduced inflowing nitrate concentrations. Decalcification also occurred in lake water, reducing water hardness, which could be beneficial for waterworks in hard groundwater areas. Downgradient groundwater nitrate and calcium concentrations were found to be stable, with only minor seasonal variations. Biological degradation of organic material and organic micropollutants was also observed in the GPLs. For young GPLs adequate sediment deposits may not yet have formed and degradation processes at the outflow may consequently not yet be well established. However, our results showed that within 5 years from the cessation of excavation a protective sediment layer is established that is sufficient to prevent the export of dissolved organic carbon to downgradient groundwater. GPLs can improve groundwater quality in anthropogenically (e.g., pesticides and nitrate) or geologically (e.g., hardness) challenging situations. However, post-excavation usage of GPLs is often dominated by human activities such as recreational activities, water sports, or fish farming. These activities will affect lake and groundwater quality and the risks involved are difficult to predict and monitor and can lead to overall negative impacts on groundwater quality. Copyright © 2012 Elsevier B

  12. Dissolved air flotation and me.

    Science.gov (United States)

    Edzwald, James K

    2010-04-01

    This paper is mainly a critical review of the literature and an assessment of what we know about dissolved air flotation (DAF). A few remarks are made at the outset about the author's personal journey in DAF research, his start and its progression. DAF has been used for several decades in drinking water treatment as an alternative clarification method to sedimentation. DAF is particularly effective in treating reservoir water supplies; those supplies containing algae, natural color or natural organic matter; and those with low mineral turbidity. It is more efficient than sedimentation in removing turbidity and particles for these type supplies. Furthermore, it is more efficient in removing Giardia cysts and Cryptosporidium oocysts. In the last 20 years, fundamental models were developed that provide a basis for understanding the process, optimizing it, and integrating it into water treatment plants. The theories were tested through laboratory and pilot-plant studies. Consequently, there have been trends in which DAF pretreatment has been optimized resulting in better coagulation and a decrease in the size of flocculation tanks. In addition, the hydraulic loading rates have increased reducing the size of DAF processes. While DAF has been used mainly in conventional type water plants, there is now interest in the technology as a pretreatment step in ultrafiltration membrane plants and in desalination reverse osmosis plants. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  13. Data from exploratory sampling of groundwater in selected oil and gas areas of coastal Los Angeles County and Kern and Kings Counties in southern San Joaquin Valley, 2014–15: California oil, gas, and groundwater project

    Science.gov (United States)

    Dillon, David B.; Davis, Tracy A.; Landon, Matthew K.; Land, Michael T.; Wright, Michael T.; Kulongoski, Justin T.

    2016-12-09

    Exploratory sampling of groundwater in coastal Los Angeles County and Kern and Kings Counties of the southern San Joaquin Valley was done by the U.S. Geological Survey from September 2014 through January 2015 as part of the California State Water Resources Control Board’s Water Quality in Areas of Oil and Gas Production Regional Groundwater Monitoring Program. The Regional Groundwater Monitoring Program was established in response to the California Senate Bill 4 of 2013 mandating that the California State Water Resources Control Board design and implement a groundwater-monitoring program to assess potential effects of well-stimulation treatments on groundwater resources in California. The U.S. Geological Survey is in cooperation with the California State Water Resources Control Board to collaboratively implement the Regional Groundwater Monitoring Program through the California Oil, Gas, and Groundwater Project.Many researchers have documented the utility of different suites of chemical tracers for evaluating the effects of oil and gas development on groundwater quality. The purpose of this exploratory sampling effort was to determine whether tracers reported in the literature could be used effectively in California. This reconnaissance effort was not designed to assess the effects of oil and gas on groundwater quality in the sampled areas. A suite of water-quality indicators and geochemical tracers were sampled at groundwater sites in selected areas that have extensive oil and gas development. Groundwater samples were collected from a total of 51 wells, including 37 monitoring wells at 17 multiple-well monitoring sites in coastal Los Angeles County and 5 monitoring wells and 9 water-production wells in southern San Joaquin Valley, primarily in Kern and Kings Counties.Groundwater samples were analyzed for field water-quality indicators; organic constituents, including volatile and semi-volatile organic compounds and dissolved organic carbon indicators; naturally

  14. Salt Pomo: An Ethnogeography

    OpenAIRE

    McCarthy, Helen

    1986-01-01

    Recent research in Salt Pomo territory has produced new ethnogeographic data to add to the named villages identified in much earlier studies (Barrett 1904, 1908; Merriam MS, 1966, 1977). This new information is of particular interest because it significantly increases our general knowledge of the Salt Pomo, about whom little is otherwise known, and because it contributes to an understanding of their settlement pattern as well as to broader, regional land-use analyses. In addition, the study a...

  15. PATHS groundwater hydrologic model

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, R.W.; Schur, J.A.

    1980-04-01

    A preliminary evaluation capability for two-dimensional groundwater pollution problems was developed as part of the Transport Modeling Task for the Waste Isolation Safety Assessment Program (WISAP). Our approach was to use the data limitations as a guide in setting the level of modeling detail. PATHS Groundwater Hydrologic Model is the first level (simplest) idealized hybrid analytical/numerical model for two-dimensional, saturated groundwater flow and single component transport; homogeneous geology. This document consists of the description of the PATHS groundwater hydrologic model. The preliminary evaluation capability prepared for WISAP, including the enhancements that were made because of the authors' experience using the earlier capability is described. Appendixes A through D supplement the report as follows: complete derivations of the background equations are provided in Appendix A. Appendix B is a comprehensive set of instructions for users of PATHS. It is written for users who have little or no experience with computers. Appendix C is for the programmer. It contains information on how input parameters are passed between programs in the system. It also contains program listings and test case listing. Appendix D is a definition of terms.

  16. GROUNDWATER RECHARGE AND CHEMICAL ...

    Science.gov (United States)

    The existing knowledge base regarding the presence and significance of chemicals foreign to the subsurface environment is large and growing -the papers in this volume serving as recent testament. But complex questions with few answers surround the unknowns regarding the potential for environmental or human health effects from trace levels of xenobiotics in groundwater, especially groundwater augmented with treated wastewater. Public acceptance for direct or indirect groundwater recharge using treated municipal wastewater ( especially sewage) spans the spectrum from unquestioned embrace to outright rejection. In this article, I detour around the issues most commonly discussed for groundwater recharge and instead focus on some of the less-recognized issues- those that emanate from the mysteries created at the many literal and virtual interfaces involved with the subsurface world. My major objective is to catalyze discussion that advances our understanding of the barriers to public acceptance of wastewater reuse -with its ultimate culmination in direct reuse for drinking. I pose what could be a key question as to whether much of the public's frustration or ambivalence in its decision making process for accepting or rejecting water reuse (for various purposes including personal use) emanates from fundamental inaccuracies, misrepresentation, or oversimplification of what water 'is' and how it functions in the environment -just what exactly is the 'water cyc

  17. Regulating groundwater use

    NARCIS (Netherlands)

    Hoogesteger van Dijk, Jaime; Wester, Flip

    2017-01-01

    Around the world it has proven very difficult to develop policies and interventions that ensure socio-environmentally sustainable groundwater use and exploitation. In the state of Guanajuato, Central Mexico, both the national government and the decentralized state government have pursued to regulate

  18. Hygroscopic Salts on Mars

    Science.gov (United States)

    Melchiorri, R.; Davila, A. F.; Chittenden, J.; Haberle, R. M.

    2008-12-01

    We present preliminary results on the influence of a salt-rich regolith in the water cycle of Mars. Global climate modeling shows that the relative humidity on the Martian surface often reaches values above the deliquescence point of salts that are common components of the regolith. At the deliquescence point, these salts will absorb atmospheric water vapor and form a saturated, transient liquid solution that is stable under a range of temperatures. If atmospheric temperatures fall below the eutectic point of the solution, the later will freeze in the pore space of the regolith, thereby resulting in a net transport of water from the vapor phase in the atmosphere, to the solid state in the regolith. This simple model partially accounts for some the distribution of water on the Martian surface as revealed by Mars Odyssey, in particular, we find that: even though the Cl and surface water distributions detected by HEND/ODYSSEY are highly correlated, salt deliquescence under the the present atmospheric conditions does not explain the overall distribution of water in the near surface regolith. However deliquescence of salt-rich soils could be an important contributor to the distribution of water in the regolith at high obliquity. In that scenario the water in the near-surface regolith would be the remnant of high obliquity conditions salt deliquescence is still active in different regions on Mars today, and it should be introduced as a parameter in the modern GCMs as a new ground/atmosphere interaction

  19. A comparison of forest and agricultural shallow groundwater chemical status a century after land use change

    Energy Technology Data Exchange (ETDEWEB)

    Kellner, Elliott, E-mail: rekfh3@mail.missouri.edu [School of Natural Resources, University of Missouri, Columbia, MO 65211 (United States); Hubbart, Jason A. [Water Resources Program, School of Natural Resources, Department of Forestry, University of Missouri, Columbia, MO 65211 (United States); Ikem, Abua, E-mail: Ikema@lincolnu.edu [Lincoln University, Department of Agriculture and Environmental Sciences, 204 Foster Hall, 904 Chestnut Street, Jefferson City, MO 65101 (United States)

    2015-10-01

    Considering the increasing pace of global land use change and the importance of groundwater quality to humans and aquatic ecosystems, studies are needed that relate land use types to patterns of groundwater chemical composition. Piezometer grids were installed in a remnant bottomland hardwood forest (BHF) and a historic agricultural field (Ag) to compare groundwater chemical composition between sites with contrasting land use histories. Groundwater was sampled monthly from June 2011 to June 2013, and analyzed for 50 physiochemical metrics. Statistical tests indicated significant differences (p < 0.05) between the study sites for 32 out of 50 parameters. Compared to the Ag site, BHF groundwater was characterized by significantly (p < 0.05) lower pH, higher electrical conductivity, and higher concentrations of total dissolved solids and inorganic carbon. BHF groundwater contained significantly (p < 0.05) higher concentrations of all nitrogen species except nitrate, which was higher in Ag groundwater. BHF groundwater contained significantly (p < 0.05) higher concentrations of nutrients such as sulfur, potassium, magnesium, calcium, and sodium, relative to the Ag site. Ag groundwater was characterized by significantly (p < 0.05) higher concentrations of trace elements such as arsenic, cadmium, cobalt, copper, molybdenum, nickel, and titanium. Comparison of shallow groundwater chemical composition with that of nearby receiving water suggests that subsurface concentration patterns are the result of contrasting site hydrology and vegetation. Results detail impacts of surface vegetation alteration on subsurface chemistry and groundwater quality, thereby illustrating land use impacts on the lithosphere and hydrosphere. This study is among the first to comprehensively characterize and compare shallow groundwater chemical composition at sites with contrasting land use histories. - Highlights: • Shallow groundwater chemical composition was compared at floodplain sites.

  20. Analisis Total Zat Padat Terlarut (Total Dissolved Solid) Dan Total Zat Padat Trsuspensi (Total Suspended Solid) Pada Air Badan Air Khususnya Air Sungai

    OpenAIRE

    Saraswaty, Asri

    2015-01-01

    Total dissolved solids ( Total Dissolved Solid ) is a measure of the solute( both organic and inorganic , for example : salt , etc.) contained in the river water. The total suspended solids (Total Suspended Solid) are solids that are in suspension , can be distinguished according to their size as suspended colloidal particles (colloidal particles) and particles suspended regular (suspended particles). The purpose of to determine whether the water meets the river that were analyzed in accordan...

  1. Purple Salt and Tiny Drops of Water in Meteorites

    Science.gov (United States)

    Taylor, G. J.

    1999-12-01

    Some meteorites, especially those called carbonaceous chondrites, have been greatly affected by reaction with water on the asteroids in which they formed. These reactions, which took place during the first 10 million years of the Solar System's history, formed assorted water-bearing minerals, but nobody has found any of the water that caused the alteration. Nobody, that is, until now. Michael Zolensky and team of scientists from the Johnson Space Center in Houston and Virginia Tech (Blacksburg, Virginia) discovered strikingly purple sodium chloride (table salt) crystals in two meteorites. The salt contains tiny droplets of salt water (with some other elements dissolved in it). The salt is as old as the Solar System, so the water trapped inside the salt is also ancient. It might give us clues to the nature of the water that so pervasively altered carbonaceous chondrites and formed oceans on Europa and perhaps other icy satellites. However, how the salt got into the two meteorites and how it trapped the water remains a mystery - at least for now.

  2. Local point sources that affect ground-water quality in the East Meadow area, Long Island, New York

    Science.gov (United States)

    Heisig, Paul M.

    1994-01-01

    The extent and chemical characteristics of ground water affected by three local point sources--a stormwater basin, uncovered road-salt-storage piles, and an abandoned sewage-treatment plant--were delineated during a 3-year study of the chemical characteristics and migration of a body of reclaimed wastewater that was applied to the watertable aquifer during recharge experiments from October 1982 through January 1984 in East Meadow. The timing, magnitude, and chemical quality of recharge from these point sources is highly variable, and all sources have the potential to skew determinations of the quality of ambient ground-water and of the reclaimed-wastewater plume if they are not taken into account. Ground water affected by recharge from the stormwater basin is characterized by low concentrations of nitrate + nitrite (less than 5 mg/L [milligrams per liter] as N) and sulfate (less than 40 mg/L) and is almost entirely within the upper glacial aquifer. The plume derived from road-salt piles is narrow, has high concentrations of chloride (greater than 50 mg/L) and sodium (greater than 75 mg/L), and also is limited to the upper glacial aquifer. The sodium, in high concentrations, could react with aquifer material and exchange for sorbed cations such as calcium, potassium, and magnesium. Water affected by secondary-treated sewage from the abandoned treatment plant extends 152 feet below land surface into the upper part of the Magothy aquifer and longitudinally beyond the southern edge of the study area, 7,750 feet south of the recharge site. Ground water affected by secondary-treated sewage within the study area typically contains elevated concentrations of reactive chemical constituents, such as potassium and ammonium, and low concentrations of dissolved oxygen. Conservative or minimally reactive constituents such as chloride and sodium have been transported out of the study area in the upper glacial aquifer and the intermediate (transitional) zone but remain in the less

  3. Dissolved organic matter composition of winter stream flow in the Yukon River basin

    Science.gov (United States)

    O'Donnell, J.; Aiken, G.; Walvoord, M. A.; Butler, K.

    2011-12-01

    In the Yukon River Basin (YRB), groundwater-to-stream discharge has increased by 0.7-0.9% yr-1 over the last three decades, and is likely in response to regional climate warming and permafrost thaw. This recent shift in watershed hydrology has important implications for the flux of dissolved organic matter (DOM) from terrestrial to freshwater and marine ecosystems and its composition. For instance, it has been hypothesized that permafrost thaw and increased groundwater discharge may account for the long-term decline in discharge-normalized dissolved organic carbon (DOC) export in the main stem of the Yukon River. However, the response of DOC dynamics in YRB subcatchments to recent warming and thaw will likely vary over space and time as a function of vegetation, parent material, ground ice content and disturbance history. To evaluate spatial patterns of groundwater DOM composition, we collected under-ice samples during winter flow from 68 streams in the YRB. Using a suite of conservative tracers (specific conductivity, base cations), we also separated the relative contribution of supra- and sub-permafrost groundwaters to winter flow. In general, DOC concentration in winter stream flow was low relative to summer flow, averaging 3.94 ± 0.46 and 18.39 ± 1.39 mg L-1. However, DOM composition varied widely across the YRB, indicating a broad range of organic matter quality and reactivity present for different groundwater sources. In streams receiving inputs primarily from sub-permafrost groundwater, we observed low specific ultraviolet absorbance (SUVA254) values (0.4-1.1 L mgC-1 m-1), a high proportion of hydrophilic compounds (35-50%), and a large proportion of protein-like compounds (13-35%, as determined by fluorescence spectroscopy). In streams where winter flow was a mixture of supra- and sub-permafrost groundwater sources, we observed higher SUVA254 values (2.0-3.6 L mgC-1 m-1), high hydrophobic acid content (43 ± 1%), and small proportion of protein

  4. Natural radioactivity in groundwater from the south-eastern Arabian Peninsula and environmental implications

    DEFF Research Database (Denmark)

    Murad, A.; Zhou, X. D.; Yi, P.

    2014-01-01

    increase the radioactivity in the groundwater. This conclusion is also supported by the positive correlation between radioactivity and amount of total dissolved solid. Particular water purification technology and environmental impact assessments are essential for sustainable and secure use......Groundwater is the most valuable resource in arid regions, and recognizing radiological criteria among other water quality parameters is essential for sustainable use. In the investigation presented here, gross-α and gross-β were measured in groundwater samples collected in the south...... permissible limits for drinking water in the majority of the investigated samples except those in region 4 (Jabel Hafit and surroundings). No correlation between groundwater pH and the gross-α and gross-β, while high temperatures probably enhance leaching of radionuclides from the aquifer body and thereby...

  5. Sea-water/groundwater interactions along a small catchment of the European Atlantic coast

    DEFF Research Database (Denmark)

    Einsiedl, Florian

    2012-01-01

    The geochemistry and isotopic composition of a karstic coastal aquifer in western Ireland has shed light on the effect of sea-water/groundwater interactions on the water quality of Ireland’s Atlantic coastal zone. The use of stable isotope data from the IAEA precipitation station in Valentia......, located in SW Ireland has facilitated the characterization of groundwater recharge conditions in the western part of Ireland and suggests that groundwater is mostly replenished by the isotopically light winter precipitation. The dissolved SO42- in the karstic groundwater that was collected during baseflow...... conditions with δ34S values between 4.6‰ and 18‰ may be composed of S stemming from three principal sources: SO42- derived from precipitation which is composed of both sea-spray S (δ34S: 20‰) and an isotopically light anthropogenic source (δ34S: 1–5‰), SO42-stemming from animal slurries (δ34S: ∼5...

  6. ASSESSMENT OF WATER QUALITY INDEX FOR GROUNDWATER OF VALSAD DISTRICT OF SOUTH GUJARAT (INDIA

    Directory of Open Access Journals (Sweden)

    P. Shroff

    2015-07-01

    Full Text Available The present study aims the assessment of the water quality index (WQI for the groundwater of Valsad district of South Gujarat. Total fifteen sampling stations from five talukas of Valsad district were selected and groundwater samples were collected for two years (from August 2007 to July 2009. In this present study, WQI created by Canadian Council of Minister of the Environment (CCME was used. For calculating the WQI, groundwater samples were analyzed for seventeen physico-chemical parameters like pH, Colour, Electrical Conductivity (EC, Total Hardness (TH, Calcium (Ca, Magnesium (Mg, Total Alkalinity (TA, Total Dissolved Solids (TDS, Silica, Chloride, Sulphate, Fluoride, Sodium, Chemical Oxygen Demand (COD and metals like Copper (Cu, Lead (Pb and Manganese (Mn.  The WQI for Valsad district suggests that the groundwater quality is marginal.  

  7. ASSESSMENT OF WATER QUALITY INDEX FOR GROUNDWATER OF VALSAD DISTRICT OF SOUTH GUJARAT (INDIA

    Directory of Open Access Journals (Sweden)

    P. Shroff

    2013-12-01

    Full Text Available The present study aims the assessment of the water quality index (WQI for the groundwater of Valsad district of South Gujarat. Total fifteen sampling stations from five talukas of Valsad district were selected and groundwater samples were collected for two years (from August 2007 to July 2009. In this present study, WQI created by Canadian Council of Minister of the Environment (CCME was used. For calculating the WQI, groundwater samples were analyzed for seventeen physico-chemical parameters like pH, Colour, Electrical Conductivity (EC, Total Hardness (TH, Calcium (Ca, Magnesium (Mg, Total Alkalinity (TA, Total Dissolved Solids (TDS, Silica, Chloride, Sulphate, Fluoride, Sodium, Chemical Oxygen Demand (COD and metals like Copper (Cu, Lead (Pb and Manganese (Mn. The WQI for Valsad district suggests that the groundwater quality is marginal.

  8. Oxygen, hydrogen, and helium isotopes for investigating groundwater systems of the Cape Verde Islands, West Africa

    Science.gov (United States)

    Heilweil, V.M.; Solomon, K.D.; Gingerich, S.B.; Verstraeten, Ingrid M.

    2009-01-01

    Stable isotopes (??18O, ??2H), tritium (3H), and helium isotopes (3He, 4He) were used for evaluating groundwater recharge sources, flow paths, and residence times of three watersheds in the Cape Verde Islands (West Africa). Stable isotopes indicate the predominance of high-elevation precipitation that undergoes little evaporation prior to groundwater recharge. In contrast to other active oceanic hotspots, environmental tracers show that deep geothermal circulation does not strongly affect groundwater. Low tritium concentrations at seven groundwater sites indicate groundwater residence times of more than 50 years. Higher tritium values at other sites suggest some recent recharge. High 4He and 3He/4He ratios precluded 3H/3He dating at six sites. These high 3He/4He ratios (R/Ra values of up to 8.3) are consistent with reported mantle derived helium of oceanic island basalts in Cape Verde and provided end-member constraints for improved dating at seven other locations. Tritium and 3H/3He dating shows that S??o Nicolau Island's Ribeira Faj?? Basin has groundwater residence times of more than 50 years, whereas Fogo Island's Mosteiros Basin and Santo Ant??o Island's Ribeira Paul Basin contain a mixture of young and old groundwater. Young ages at selected sites within these two basins indicate local recharge and potential groundwater susceptibility to surface contamination and/or salt-water intrusion. ?? Springer-Verlag 2009.

  9. Mapping Model of Groundwater Catchment Area based on Geological Fault : Case Study in Semarang City

    Directory of Open Access Journals (Sweden)

    Qudus, N.

    2016-04-01

    Full Text Available Groundwater is a naturally renewable resource because groundwater is an integral part of hydrological cycle. However, in reality, there are many limiting factors which influence its usage, in both quality and quantity, the provision ability of groundwater will decrease if its availability is exceeded. The problems of ground water potential in both quantity and quality are always related to its constituents' characteristics or its geological element where the groundwater resides. This present study aims at determining the groundwater catchment area based on the geological condition of an area so that groundwater recharge can be accomplished. In addition, it is necessary for groundwater catchment area to comply with the geological condition. The geologically unfit area will only result in land movement or landslide if it is used as groundwater catchment area. The results of geo-electricity analysis which was conducted in Semarang city showed that there are 3 faults; Sukorejo fault, Tinjomoyo fault and Jangli fault which will be explained in detail in the paper. Those faults intersect the underground water stream in Semarang from south to north towards the Java Sea. The majority of underground water stream in Semarang flows from south to north. In contrary, the results of the analysis showed that there are some points that become local basins such as in the south area and southwest of Semarang where flow direction is on the opposite direction. In addition, the results of the analysis showed that some coastal areas in Semarang have experienced salt water intrusion.

  10. An assessment of groundwater quality using water quality index in Chennai, Tamil Nadu, India

    Directory of Open Access Journals (Sweden)

    I Nanda Balan

    2012-01-01

    Full Text Available Context : Water, the elixir of life, is a prime natural resource. Due to rapid urbanization in India, the availability and quality of groundwater have been affected. According to the Central Groundwater Board, 80% of Chennai′s groundwater has been depleted and any further exploration could lead to salt water ingression. Hence, this study was done to assess the groundwater quality in Chennai city. Aim : To assess the groundwater quality using water quality index in Chennai city. Materials and Methods: Chennai city was divided into three zones based on the legislative constituency and from these three zones three locations were randomly selected and nine groundwater samples were collected and analyzed for physiochemical properties. Results: With the exception of few parameters, most of the water quality assessment parameters showed parameters within the accepted standard values of Bureau of Indian Standards (BIS. Except for pH in a single location of zone 1, none of the parameters exceeded the permissible values for water quality assessment as prescribed by the BIS. Conclusion: This study demonstrated that in general the groundwater quality status of Chennai city ranged from excellent to good and the groundwater is fit for human consumption based on all the nine parameters of water quality index and fluoride content.

  11. A novel approach for direct estimation of fresh groundwater discharge to an estuary

    Science.gov (United States)

    Ganju, Neil K.

    2011-01-01

    Coastal groundwater discharge is an important source of freshwater and nutrients to coastal and estuarine systems. Directly quantifying the spatially integrated discharge of fresh groundwater over a coastline is difficult due to spatial variability and limited observational methods. In this study, I applied a novel approach to estimate net freshwater discharge from a groundwater-fed tidal creek over a spring-neap cycle, with high temporal resolution. Acoustic velocity instruments measured tidal water fluxes while other sensors measured vertical and lateral salinity to estimate cross-sectionally averaged salinity. These measurements were used in a time-dependent version of Knudsen's salt balance calculation to estimate the fresh groundwater contribution to the tidal creek. The time-series of fresh groundwater discharge shows the dependence of fresh groundwater discharge on tidal pumping, and the large difference between monthly mean discharge and instantaneous discharge over shorter timescales. The approach developed here can be implemented over timescales from days to years, in any size estuary with dominant groundwater inputs and well-defined cross-sections. The approach also directly links delivery of groundwater from the watershed with fluxes to the coastal environment. Copyright. Published in 2011 by the American Geophysical Union.

  12. Carbon-14 as a tracer of groundwater discharge to streams

    Science.gov (United States)

    Bourke, Sarah; Harrington, Glenn; Cook, Peter; Post, Vincent; Dogramaci, Shawan

    2014-05-01

    The provenance of groundwater discharge to a stream can be determined by measuring the response of multiple groundwater age tracers within the stream across the discharge zone. The sampling interval required to detect groundwater discharge is limited by the rate of equilibration with the atmosphere downstream of the discharge zone, which is determined by the gas transfer velocity. Carbon-14 (14C) equilibration is driven by CO2 exchange, which is a small component of the dissolved inorganic carbon in most stream systems, and therefore the rate of equilibration is slower than for other gaseous age tracers. In this paper we use a step-wise approach to develop and demonstrate the use of 14C as a tracer in streams receiving groundwater discharge. Excess carbon dioxide (CO2) in the emerging groundwater degasses until equilibrium with atmospheric CO2 is reached; increasing pH and enriching the residual 14C by fractionation. In addition, the 14C gradient between groundwater and the atmosphere drives a slower process of isotopic equilibration. We have measured the rates of this chemical and isotopic equilibration experimentally by exposing 250 L of old groundwater to the atmosphere in an evaporation pan. Chemical equilibrium was achieved within 2 days, during which the 14C increased from 6 to 16 pMC. The influence of fractionation during the initial CO2 degassing on isotopic equilibrium rates was negligible. Isotopic equilibrium took over 2 months, with 14C in the evaporation pan increasing to 108 pMC over 71 days. This increase in 14C was simulated using a mass balance model with an effective 14C gas transfer velocity of 0.013 m d-1. Field testing of the method was conducted at two sites. Firstly, we measured the evolution of 14C in dewatering discharge as it flows along an ephemeral creek channel in the Pilbara, Western Australia. Measured 14C increased from 11 to 31 pMC along the 10km reach, which corresponds to a travel time of about 2 days. The measured increase was

  13. Semivolatile organic (GC-MS) and inorganic analyses of groundwater samples during the hydrous pyrolysis/oxidation (HPO) field test in Visalia, CA, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Chiarappa, M; Knauss, K G; Kumamoto, G; Leif, R N; Newmark, R L

    1998-02-05

    Hydrous pyrolysis/oxidation (HPO) is a novel, in situ, thermal-remediation technology that uses hot, oxygenated groundwater to completely oxidize a wide range of organic pollutants. A field demonstration of HPO was performed during the summer of 1997 at the Southern California Edison Pole Yard in Visalia, California, a site contaminated with creosote. The goal of the field experiment was to confirm the success of HPO under field remediation conditions. The groundwater was heated by steam injections, and oxygen was added by co-injection of compressed air. The progress of the HPO remediation process was evaluated by monitoring groundwater from multiple wells for dissolved oxygen, dissolved inorganic carbon, and dissolved organic contaminant levels. Analyses of groundwater chemistry allowed us to measure the concentrations of creosote components and to identify oxygenated intermediates produced by the HPO treatment. Dissolved organic carbon levels increased in response to steam injections because of the enhanced dissolution and mobilization of the creosote into the heated groundwater. Elevated concentrations of phenols and benzoic acid were measured in wells affected by the steam injections. Concentrations of other oxygenated compounds (i.e., fluorenone, anthrone, and 9,10-anthracenedione) increased in response to the steam injections. The production of these partially oxidized compounds is consistent with the aqueous-phase HPO reactions of creosote. Additional changes in the groundwater in response to steam injection were also consistent with the groundwater HPO chemistry. A drop in dissolved oxygen was observed in the aquifer targeted for the steam injections, and isotope shifts in the dissolved inorganic pool reflected the input of oxidized carbon derived from the creosote carbon.

  14. Assessing Connectivity Between an Overlying Aquifer and a Coal Seam Gas Resource Using Methane Isotopes, Dissolved Organic Carbon and Tritium

    Science.gov (United States)

    Iverach, Charlotte P.; Cendón, Dioni I.; Hankin, Stuart I.; Lowry, David; Fisher, Rebecca E.; France, James L.; Nisbet, Euan G.; Baker, Andy; Kelly, Bryce F. J.

    2015-11-01

    Coal seam gas (CSG) production can have an impact on groundwater quality and quantity in adjacent or overlying aquifers. To assess this impact we need to determine the background groundwater chemistry and to map geological pathways of hydraulic connectivity between aquifers. In south-east Queensland (Qld), Australia, a globally important CSG exploration and production province, we mapped hydraulic connectivity between the Walloon Coal Measures (WCM, the target formation for gas production) and the overlying Condamine River Alluvial Aquifer (CRAA), using groundwater methane (CH4) concentration and isotopic composition (δ13C-CH4), groundwater tritium (3H) and dissolved organic carbon (DOC) concentration. A continuous mobile CH4 survey adjacent to CSG developments was used to determine the source signature of CH4 derived from the WCM. Trends in groundwater δ13C-CH4 versus CH4 concentration, in association with DOC concentration and 3H analysis, identify locations where CH4 in the groundwater of the CRAA most likely originates from the WCM. The methodology is widely applicable in unconventional gas development regions worldwide for providing an early indicator of geological pathways of hydraulic connectivity.

  15. A mechanistic study of nonlinear solute transport in a groundwater-surface water system Under steady state and transient hydraulic conditions

    Science.gov (United States)

    Boufadel, Michel C.

    2000-09-01

    Two laboratory experiments were conducted to investigate the effects of tides and buoyancy on beach hydraulics in the presence of a seaward groundwater flow due to an elevated "regional" water table. In the first experiment, case 1, the difference in concentration between the salt water at sea and the water of the regional aquifer was small, 2.4 g L-1, such that it did not engender density gradients; the salt acts as a tracer in this case. In the second experiment, case 2, the difference was ˜32.0 g L-1, which creates a significant density gradient. This case corresponds to the presence of fresh groundwater in the subsurface of the coasts of the continental United States. The experiments were numerically simulated by the marine unsaturated (MARUN) model, a numerical model for density-and-viscosity-dependent flows in two-dimensional variably saturated media. The long-term experimental and numerical results showed that the seawater plume entered the beach from the sea and occupied most of the intertidal zone. The maximum depth of the seawater plume was near the midsection of the intertidal zone, and it decreased near the low and high tide lines. When viewed in the context of case 2, these results indicate an inverted salinity distribution in beaches subjected to tides with salt water from sea overtopping the freshwater lens. For both cases, water from the regional aquifer moved seaward beneath the seawater in the intertidal zone and pinched out near the low tide mark. We also noted that beach hydraulics are highly two dimensional with water entering the beach at a near-vertical angle and leaving it at a near-horizontal angle, which casts doubts on analyses of beach hydraulics based on the Dupuit assumption. Findings from this work have direct implications within the practice of bioremediation of oil spills on beaches. We found that applying dissolved nutrients on the beach surface at low tide is superior to applying them in a trench landward of the beach. This is

  16. River stage influences on uranium transport in a hydrologically dynamic groundwater-surface water transition zone: U TRANSPORT IN A GROUNDWATER-SURFACE WATER TRANSITION ZONE

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M. [Pacific Northwest National Laboratory, Richland Washington USA; Chen, Xingyuan [Pacific Northwest National Laboratory, Richland Washington USA; Murray, Chris [Pacific Northwest National Laboratory, Richland Washington USA; Hammond, Glenn [Sandia National Laboratories, Albuquerque New Mexico USA

    2016-03-01

    A tightly spaced well-field within a groundwater uranium (U) plume in the groundwater-surface water transition zone was monitored for a three year period for groundwater elevation and dissolved solutes. The plume discharges to the Columbia River, which displays a dramatic spring stage surge resulting from mountain snowmelt. Groundwater exhibits a low hydrologic gradient and chemical differences with river water. River water intrudes the site in spring. Specific aims were to assess the impacts of river intrusion on dissolved uranium (Uaq), specific conductance (SpC), and other solutes, and to discriminate between transport, geochemical, and source term heterogeneity effects. Time series trends for Uaq and SpC were complex and displayed large temporal well-to well variability as a result of water table elevation fluctuations, river water intrusion, and changes in groundwater flow directions. The wells were clustered into subsets exhibiting common temporal behaviors resulting from the intrusion dynamics of river water and the location of source terms. Concentration hot spots were observed in groundwater that varied in location with increasing water table elevation. Heuristic reactive transport modeling with PFLOTRAN demonstrated that mobilized U was transported between wells and source terms in complex trajectories, and was diluted as river water entered and exited the groundwater system. While uranium time-series concentration trends varied significantly from year to year as a result of climate-caused differences in