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Sample records for air soil groundwater

  1. The role of soil air composition for noble gas tracer applications in tropical groundwater

    NASA Astrophysics Data System (ADS)

    Mayer, Simon; Jenner, Florian; Aeschbach, Werner; Weissbach, Therese; Peregovich, Bernhard; Machado, Carlos

    2016-04-01

    Dissolved noble gases (NGs) in groundwater provide a well-established tool for paleo temperature reconstruction. However, reliable noble gas temperature (NGT) determination needs appropriate assumptions or rather an exact knowledge of soil air composition. Deviations of soil air NG partial pressures from atmospheric values have already been found in mid latitudes during summer time as a consequence of subsurface oxygen depletion. This effect depends on ambient temperature and humidity and is thus expected to be especially strong in humid tropical soils, which was not investigated so far. We therefore studied NGs in soil air and shallow groundwater near Santarém (Pará, Brazil) at the end of the rainy and dry seasons, respectively. Soil air data confirms a correlation between NG partial pressures, the sum value of O2+CO2 and soil moisture contents. During the rainy season, we find significant NG enhancements in soil air by up to 7% with respect to the atmosphere. This is twice as much as observed during the dry season. Groundwater samples show neon excess values between 15% and 120%. Nearly all wells show no seasonal variations of excess air, even though the local river level seasonally fluctuates by about 8 m. Assuming atmospheric NG contents in soil air, fitted NGTs underestimate the measured groundwater temperature by about 1-2° C. However, including enhanced soil air NG contents as observed during the rainy season, resulting NGTs are in good agreement with local groundwater temperatures. Our presented data allows for a better understanding of subsurface NG variations. This is essential with regard to NG tracer applications in humid tropical areas, for which reliable paleoclimate data is of major importance for modern climate research.

  2. Evaluation of short-term tracer fluctuations in groundwater and soil air in a two year study

    NASA Astrophysics Data System (ADS)

    Jenner, Florian; Mayer, Simon; Aeschbach, Werner; Weissbach, Therese

    2016-04-01

    The application of gas tracers like noble gases (NGs), SF6 or CFCs in groundwater studies such as paleo temperature determination requires a detailed understanding of the dynamics of reactive and inert gases in the soil air with which the infiltrating water equilibrates. Due to microbial gas consumption and production, NG partial pressures in soil air can deviate from atmospheric air, an effect that could bias noble gas temperatures estimates if not taken into account. So far, such an impact on NG contents in groundwater has not been directly demonstrated. We provide the first long-term study of the above mentioned gas tracers and physical parameters in both the saturated and unsaturated soil zone, sampled continuously for more than two years near Mannheim (Germany). NG partial pressures in soil air correlate with soil moisture and the sum value of O2+CO2, with a maximal significant enhancement of 3-6% with respect to atmospheric air during summer time. Observed seasonal fluctuations result in a mass dependent fractionation of NGs in soil air. Concentrations of SF6 and CFCs in soil air are determined by corresponding fluctuations in local atmospheric air, caused by industrial emissions. Arising concentration peaks are damped with increasing soil depth. Shallow groundwater shows short-term NG fluctuations which are smoothed within a few meters below the water table. A correlation between NG contents of soil air and of groundwater is observable during strong recharge events. However, there is no evidence for a permanent influence of seasonal variations of soil air composition on shallow groundwater. Fluctuating NG contents in shallow groundwater are rather determined by variations of soil temperature and water table level. Our data gives evidence for a further temperature driven equilibration of groundwater with entrapped air bubbles within the topmost saturated zone, which permanently occurs even some years after recharge. Local subsurface temperature fluctuations

  3. Field study of pulsed air sparging for remediation of petroleum hydrocarbon contaminated soil and groundwater.

    PubMed

    Yang, Xiaomin; Beckmann, Dennis; Fiorenza, Stephanie; Niedermeier, Craig

    2005-09-15

    Recent laboratory-scale studies strongly suggested an advantage to operating air-sparging systems in a pulsed mode; however, little definitive field data existed to support the laboratory-scale observations. This study aimed to evaluate the performance of a field-scale pulsed air-sparging system during a short-term pilot test and during long-term system operation. The air-sparging system consisted of 32 sparging points and had been previously operated in a continuous mode for two years before the field study was performed. The field study used instruments with continuous data logging capabilities to monitor the dynamic responses of groundwater and soil vapor parameters to air injection. The optimum pulsing frequency was based on the evidence that the hydrocarbon volatilization and oxygen dissolution rates dramatically dropped after the air-sparging system reached steady state. The short-term pilot test results indicated a substantial increase in hydrocarbon volatilization and biodegradation in pulsed operation. On the basis of the results of the pilottest, the air-sparging system was set to operate in a pulsed mode at an optimum pulsing frequency. Operation parameters were collected 2, 8, and 12 months after the start of the pulsed operation. The long-term monitoring results showed thatthe pulsed operation increased the average hydrocarbon removal rate (kg/day) by a factor of up to 3 as compared to the previous continuous operation. The pulsed air sparging has resulted in higher reduction rates of dissolved benzene, toluene, ethylbenzene, and xylenes (BTEX) than were observed during the continuous operation. Among BTEX, benzene's reduction rate was the highest during the pulsed air-sparging operation. PMID:16201659

  4. Field study of pulsed air sparging for remediation of petroleum hydrocarbon contaminated soil and groundwater.

    PubMed

    Yang, Xiaomin; Beckmann, Dennis; Fiorenza, Stephanie; Niedermeier, Craig

    2005-09-15

    Recent laboratory-scale studies strongly suggested an advantage to operating air-sparging systems in a pulsed mode; however, little definitive field data existed to support the laboratory-scale observations. This study aimed to evaluate the performance of a field-scale pulsed air-sparging system during a short-term pilot test and during long-term system operation. The air-sparging system consisted of 32 sparging points and had been previously operated in a continuous mode for two years before the field study was performed. The field study used instruments with continuous data logging capabilities to monitor the dynamic responses of groundwater and soil vapor parameters to air injection. The optimum pulsing frequency was based on the evidence that the hydrocarbon volatilization and oxygen dissolution rates dramatically dropped after the air-sparging system reached steady state. The short-term pilot test results indicated a substantial increase in hydrocarbon volatilization and biodegradation in pulsed operation. On the basis of the results of the pilottest, the air-sparging system was set to operate in a pulsed mode at an optimum pulsing frequency. Operation parameters were collected 2, 8, and 12 months after the start of the pulsed operation. The long-term monitoring results showed thatthe pulsed operation increased the average hydrocarbon removal rate (kg/day) by a factor of up to 3 as compared to the previous continuous operation. The pulsed air sparging has resulted in higher reduction rates of dissolved benzene, toluene, ethylbenzene, and xylenes (BTEX) than were observed during the continuous operation. Among BTEX, benzene's reduction rate was the highest during the pulsed air-sparging operation.

  5. Air sparging/high vacuum extraction to remove chlorinated solvents in groundwater and soil

    SciTech Connect

    Phelan, J.M.; Gilliat, M.D.

    1998-11-01

    An air sparging and high vacuum extraction was installed as an alternative to a containment pump and treat system to reduce the long-term remediation schedule. The site is located at the DOE Mound facility in Miamisburg, Ohio, just south of Dayton. The air sparging system consists of 23 wells interspersed between 17 soil vapor extraction wells. The SVE system has extracted about 1,500 lbs of VOCs in five months. The air sparging system operated for about 6 weeks before shutdown due to suspected biochemical fouling. Technical data are presented on the operating characteristics of the system.

  6. Screening for volatile organic compounds in soil and groundwater by use of a portable gas chromatograph during field investigations at an Air Force installation in Ohio

    USGS Publications Warehouse

    Parnell, James M.

    1995-01-01

    The use of the portable gas chromatograph for screening of soil and water samples in the field was part of the drilling program for the installation of monitoring wells for a basewide ground-water monitoring program at Wright-Patterson Air Force Base, Ohio. Selected soil and ground-water samples were screened in the field for volatile organic compounds to determine if contamination was present, to define the vertical and lateral extent of contamination, and to aid in the placement of the well screens for optimal interception of contaminants. This report describes the screening methods, sample-collection, quality-assurance/quality-control methods, and data-interpretation procedures necessary for screening of soil and ground-water samples in the field during the water resources investigations.

  7. Air sparging of organic compounds in groundwater

    SciTech Connect

    Hicks, P.M.

    1994-12-31

    Soils and aquifers containing organic compounds have been traditionally treated by excavation and disposal of the soil and/or pumping and treating the groundwater. These remedial options are often not practical or cost effective solutions. A more favorable alternative for removal of the adsorbed/dissolved organic compounds would be an in situ technology. Air sparging will remove volatile organic compounds from both the adsorbed and dissolved phases in the saturated zone. This technology effectively creates a crude air stripper below the aquifer where the soil acts as the ``packing``. The air stream that contacts dissolved/adsorbed phase organics in the aquifer induces volatilization. A case history illustrates the effectiveness of air sparging as a remedial technology for addressing organic compounds in soil and groundwater. The site is an operating heavy equipment manufacturing facility in central Florida. The soil and groundwater below a large building at the facility was found to contain primarily diesel type petroleum hydrocarbons during removal of underground storage tanks. The organic compounds identified in the groundwater were Benzene, Xylenes, Ethylbenzene and Toluenes (BTEX), Methyl tert-Butyl Ether (MTBE) and naphthalenes in concentrations related to diesel fuel.

  8. Use of combined air sparging and soil vacuum extraction (AS/SVE) and groundwater recovery and treatment as remedial alternatives for dissolved DNAPL recovery

    SciTech Connect

    Sturdivant, R. Jr.; Fulton, G.A. Jr.; Bains, F.E.

    1995-10-01

    Corrective action has been implemented to address a dissolved dense non-aqueous phase liquid (DNAPL) plume in the vicinity of a former waste impoundment at the Paxon Polymer Company facility, located north of Baton Rouge, Louisiana. Assessment activities focused on the characterization of the geologic and hydrologic properties of the sediments underlying the area of investigation and the impact of the dissolved DNAPL plume to the soils and groundwater. Geologic characterization revealed that the facility is underlain by Quaternary age sediments consisting of mixtures of fine-grained sands, silt, and clay. Two hydrologic units were identified within the shallow sediments which are referred to as the Upper Permeable Zone and Second Permeable Zone. The investigation focused on the impacted soils and groundwater of the Upper and Second Permeable Zones. The Upper and Second Permeable Zones were characterized hydrologically to determine the most applicable remedial alternative for addressing the dissolved DNAPL plume. Pilot tests consisting of soil vacuum extraction (SVE), combined air sparging with SVE (AS/SVE), and groundwater recovery were performed. Evaluation of these remedial technology alternatives resulted in the selection of the combined AS/SVE system alternative for the Upper Permeable Zone and the groundwater recovery alternative for the Second Permeable Zone. Recovered off-gas from the combined AS/SVE treatment system from the Upper Permeable Zone is treated through use of a granular activated carbon unit, while recovered groundwater form the Second Permeable Zone is treated by use of a low-profile air stripper.

  9. Soil- and groundwater-quality data for petroleum hydrocarbon compounds within Fuels Area C, Ellsworth Air Force Base, South Dakota, 2014

    USGS Publications Warehouse

    Bender, David A.; Rowe, Barbara L.

    2015-01-01

    Ellsworth Air Force Base is an Air Combat Command located approximately 10 miles northeast of Rapid City, South Dakota. Ellsworth Air Force Base occupies about 6,000 acres within Meade and Pennington Counties, and includes runways, airfield operations, industrial areas, housing, and recreational facilities. Fuels Area C within Ellsworth Air Force Base is a fuels storage area that is used to support the mission of the base. In fall of 2013, the U.S. Geological Survey began a study in cooperation with the U.S. Air Force, Ellsworth Air Force Base, to estimate groundwater-flow direction, select locations for permanent monitoring wells, and install and sample monitoring wells for petroleum hydrocarbon compounds within Fuels Area C. Nine monitoring wells were installed for the study within Fuels Area C during November 4–7, 2014. Soil core samples were collected during installation of eight of the monitoring wells and analyzed for benzene, toluene, ethylbenzene, total xylenes, naphthalene,m- and p-xylene, o-xylene, and gasoline- and diesel-range organic compounds. Groundwater samples were collected from seven of the nine wells (two of the monitoring wells did not contain enough water to sample or were dry) during November 19–21, 2014, and analyzed for select physical properties, benzene, toluene, ethylbenzene, total xylenes, naphthalene, m- and p-xylene, o-xylene, and gasoline- and diesel-range organic compounds. This report describes the nine monitoring well locations and presents the soil- and groundwater-quality data collected in 2014 for this study.

  10. Hydrocarbon contaminated soils and groundwater

    SciTech Connect

    Kostecki, P.T.

    1992-01-01

    This book contains the proceedings of hydrocarbon contaminated soils and groundwater. Topics covered include: Perspectives on hydrocarbon contamination; regulations; environmental fate and modeling; sampling and site assessment; remediation assessment and design; and remediation case studies.

  11. Full-scale testing and early production results from horizontal air sparging and soil vapor extraction wells remediating jet fuel in soil and groundwater at JFK International Airport, New York

    SciTech Connect

    Roth, R.J.; Bianco, P.; Kirshner, M.; Pressly, N.C.

    1996-12-31

    Jet fuel contaminated soil and groundwater contaminated at the International Arrivals Building (IAB) of the JFK International Airport in Jamaica, New York, are being remediated using soil vapor extraction (SVE) and air sparging (AS). The areal extent of the contaminated soil is estimated to be 70 acres and the volume of contaminated groundwater is estimated to be 2.3 million gallons. The remediation uses approximately 13,000 feet of horizontal SVE (HSVE) wells and 7,000 feet of horizontal AS (HAS) wells. The design of the HSVE and HAS wells was based on a pilot study followed by a full-scale test. In addition to the horizontal wells, 28 vertical AS wells and 15 vertical SVE wells are used. Three areas are being remediated, thus, three separate treatment systems have been installed. The SVE and AS wells are operated continuously while groundwater will be intermittently extracted at each HAS well, treated by liquid phase activated carbon and discharged into stormwater collection sewerage. Vapors extracted by the SVE wells are treated by vapor phase activated carbon and discharged into ambient air. The duration of the remediation is anticipated to be between two and three years before soil and groundwater are remediated to New York State cleanup criteria for the site. Based on the monitoring data for the first two months of operation, approximately 14,600 lbs. of vapor phase VOCs have been extracted. Analyses show that the majority of the VOCs are branched alkanes, branched alkenes, cyclohexane and methylated cyclohexanes.

  12. Results of soil, ground-water, surface-water, and streambed-sediment sampling at Air Force Plane 85, Columbus, Ohio, 1996

    USGS Publications Warehouse

    Parnell, J.M.

    1997-01-01

    The U.S. Geological Survey (USGS), in cooperation with Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, prepared the Surface- and Ground- Water Monitoring Work Plan for Air Force Plant 85 (AFP 85 or Plant), Columbus, Ohio, under the Air Force Installation Restoration Program to characterize any ground-water, surface-water, and soil contamination that may exist at AFP 85. The USGS began the study in November 1996. The Plant was divided into nine sampling areas, which included some previously investi gated study sites. The investigation activities included the collection and presentation of data taken during drilling and water-quality sampling. Data collection focused on the saturated and unsatur ated zones and surface water. Twenty-three soil borings were completed. Ten monitoring wells (six existing wells and four newly constructed monitoring wells) were selected for water-quality sam pling. Surface-water and streambed-sediment sampling locations were chosen to monitor flow onto and off of the Plant. Seven sites were sampled for both surface-water and streambed-sediment quality. This report presents data on the selected inorganic and organic constituents in soil, ground water, surface water, and streambed sediments at AFP 85. The methods of data collection and anal ysis also are included. Knowledge of the geologic and hydrologic setting could aid Aeronautical Systems Center, Environmental Management Directorate, Restoration Division, and its governing regulatory agencies in future remediation studies.

  13. Groundwater treatment with zero air emissions

    SciTech Connect

    Cheuvront, D.A. ); Giggy, C.L.; Loven, C.G. ); Swett, G.H. )

    1990-08-01

    Air emissions from the treatment of volatile organic compound (VOC) - contaminated groundwater are a growing problem in the US. Historically, air stripping has been used to remove VOCs from contaminated groundwater. Air stripping technology is a cross media treatment technique, i.e., it solves a groundwater problem by transferring contamination to the atmosphere. In response to the air pollution problem created by air stripping, the public, air quality regulatory agencies, the federal government and private industry are exerting pressure to eliminate and/or reduce air emissions from the clean-up of contaminated groundwater. These forces make it desirable to consider alternative and innovative technologies for the treatment of groundwater contaminated with VOCs.

  14. Low maintenance hydrocarbon soil & groundwater

    SciTech Connect

    Seabolt, L.K. Jr.; Ryckman, M.D.

    1995-12-31

    This paper illustrates practical methods to control remedial system life cycle costs for pump and treat and biovent systems through the use of low maintenance treatment systems. Cost control factors will be illustrated through the presentation of three case histories: a groundwater free product recovery system at an Air Force P.O.L. (Petroleum, Oil, and Lubricant) storage area, a free product recovery and bioventing system at a beverage fleet distribution facility, and a free product recovery and ventilation system at a publication facility.

  15. [Study on the groundwater petroleum contaminant remediation by air sparging].

    PubMed

    Wang, Zhi-Qiang; Wu, Qiang; Zou, Zu-Guang; Chen, Hong; Yang, Xun-Chang; Zhao, Ji-Chu

    2007-04-01

    The groundwater petroleum contaminant remediation effect by air sparging was investigated in an oil field. The results show that the soil geological situation has great influence on the air distribution, and the shape of air distribution is not symmetrical to the air sparging (AS) well as axis. The influence distance in the left of AS well is 6 m, and only 4 m in the right. The petroleum removal rate can reach 70% in the zone with higher air saturation, but only 40% in the zone with lower air saturation, and the average petroleum removal rate reaches 60% in the influence zone for 40 days continuous air sparging. The petroleum components in groundwater were analyzed by GC/MS (gas chromatogram-mass spectrograph) before and after experiments, respectively. The results show that the petroleum removal rate has relationship with the components and their properties. The petroleum components with higher volatility are easily removed by volatilization, but those with lower volatility are difficult to remove, so a tailing effect of lingering residual contaminant exists when the air sparging technology is adopted to treat groundwater contaminated by petroleum products.

  16. TECHNOLOGY ASSESSMENT OF SOIL VAPOR EXTRACTION AND AIR SPARGING

    EPA Science Inventory

    Air sparging, also called "in situ air stripping and in situ volatilization" injects air into the saturated zone to strip away volatile organic compounds (VOCs) dissolved in groundwater and adsorbed to soil. hese volatile contaminants transfer in a vapor phase to the unsaturated ...

  17. Evaluating potential groundwater contamination from contaminated soils

    SciTech Connect

    Pratt, J.R.; McCormick, P.V.; Pontasch, K.W.; Cairns, J.

    1987-01-01

    Contamination of soils at toxic and hazardous-waste sites can adversely affect groundwater and surface water. Water-soluble materials can move in soil by leaching and percolation and by runoff. The project evaluated the toxicity of leachable toxicants from seven soils, five of which were obtained from designated toxic or hazardous-waste sites. Acidified, dechlorinated tap water was used to extract toxic materials from surface soils. Extracts were used as complex mixtures in acute-toxicity tests using Daphnia and in chronic-effect tests using microcosms. Three classes of effects were observed. Some leachates (including control soils) showed no toxicity. Some soil leachates had moderate acute toxicity (50-80% diluted leachate) and no chronic toxicity. Very toxic soils showed both acute and chronic toxicity at <3% leachate. Toxicological evaluations of contaminants in waste-site soils can provide information not available from chemical analyses and may be useful in verifying the effectiveness of cleanup effort.

  18. Urban soil moisture affecting local air temperature

    NASA Astrophysics Data System (ADS)

    Wiesner, Sarah; Ament, Felix; Eschenbach, Annette

    2015-04-01

    The climate in cities differs from that in the surrounding area due to modified surfaces. Parameters like surface sealing ratio, vegetation and building material are known to be relevant for the intensity of the microclimatic modification. But what about the influence of soil moisture content and availability at the soil surface? Soil acts as a storage and transmitter for water. In doing so, it may have a differently pronounced impact on local climate through distinct evapotranspiration. The actual evapotranspiration rates are determined by water availability at the surface - dependant from soil physical properties and water refill from above or below - and the presence of evapotranspirators, i.e. plants that transpire water from deeper soil areas. The issue of soil hydrological characteristics and water replenishment limiting the local cooling effect of soils is the topic of this contribution. A long-term record (2010-2014) of ongoing measurements in the city of Hamburg, Germany, is evaluated. The data is provided by atmospheric and pedologic measurement sites of the HUSCO network (Hamburg Urban Soil Climate Observatory). They are located within six urban districts: the city core, four suburban districts, featuring different mean groundwater table depths (> 5 m below surface / < 2.5 m below surface), and one industrial area. The temporal evolutions of water content and soil water tension of the suburban soil profiles are found to be very diverse, related to soil substrate, organic matter content and groundwater table depth. Most distinct variations are observed within the upper horizons of suburban soil. Soil hydrological processes show characteristic patterns at each measurement site, including topsoil water content (Θ) variability. Yet, differences between distinct urban land use types are visible only according to differences in the prevailing soil texture. Impacts of different vegetation types on the soil water dynamics can be identified, while the influence

  19. Soil-aquifer phenomena affecting groundwater under vertisols: a review

    NASA Astrophysics Data System (ADS)

    Kurtzman, D.; Baram, S.; Dahan, O.

    2016-01-01

    Vertisols are cracking clayey soils that (i) usually form in alluvial lowlands where, normally, groundwater pools into aquifers; (ii) have different types of voids (due to cracking), which make flow and transport of water, solutes and gas complex; and (iii) are regarded as fertile soils in many areas. The combination of these characteristics results in the unique soil-aquifer phenomena that are highlighted and summarized in this review. The review is divided into the following four sections: (1) soil cracks as preferential pathways for water and contaminants: in this section lysimeter-to basin-scale observations that show the significance of cracks as preferential-flow paths in vertisols, which bypass matrix blocks in the unsaturated zone, are summarized. Relatively fresh-water recharge and groundwater contamination from these fluxes and their modeling are reviewed; (2) soil cracks as deep evaporators and unsaturated-zone salinity: deep sediment samples under uncultivated vertisols in semiarid regions reveal a dry (immobile), saline matrix, partly due to enhanced evaporation through soil cracks. Observations of this phenomenon are compiled in this section and the mechanism of evapoconcentration due to air flow in the cracks is discussed; (3) impact of cultivation on flushing of the unsaturated zone and aquifer salinization: the third section examines studies reporting that land-use change of vertisols from native land to cropland promotes greater fluxes through the saline unsaturated-zone matrix, eventually flushing salts to the aquifer. Different degrees of salt flushing are assessed as well as aquifer salinization on different scales, and a comparison is made with aquifers under other soils; (4) relatively little nitrate contamination in aquifers under vertisols: in this section we turn the light on observations showing that aquifers under cultivated vertisols are somewhat resistant to groundwater contamination by nitrate (the major agriculturally related

  20. Comparison of groundwater colloids in adjoining soils of Florida flatwoods

    SciTech Connect

    Tan, Z.X.; Harris, W.G.; Ma, L.Q.

    2000-02-01

    Colloids in soil water are a constituent of natural geochemical fluxes and have the potential to facilitate contaminant transport, but few data are available on their composition and concentration. This study addresses how the composition and concentration of groundwater solids relate to hydrological and soil morphological variables of the Florida flatwoods landscape. Groundwater from saturated soil horizons was sampled biweekly for 1 year along an Aquod/Udult boundary using piezometers designed specifically to minimize disturbance and to permit the valid assessment of suspended solids. Readily dispersible clay from core samples of soil horizons was collected and quantified. Groundwater and soil colloids were analyzed physically, chemically, and mineralogically. Aquod groundwater had consistently lower pH, higher electrical conductivity, and more total solids (TS) and organic carbon (OC) than did Udult groundwater. Significant decreases in both TS and OC concentrations in groundwater occurred with depth for both soils. In contrast, the mineralogy of groundwater colloids was insensitive to soil and horizon differences. Quartz dominated inorganic colloid fractions in groundwater samples from all horizons, even in argillic horizons where clay fractions contained little or no quartz. No statistical correlations were found between masses of groundwater colloids and soil water-dispersible clay. However, the proportion of organic carbon was higher in groundwater than in soil matrices. Results are consistent with carbon and colloidal quartz movement in shallow groundwater of the soil studied and document that natural colloid and solute fluxes can be highly soil specific.

  1. Is there a relationship between soil and groundwater toxicity?

    PubMed

    Sheehan, P; Dewhurst, R E; James, S; Callaghan, A; Connon, R; Crane, M

    2003-03-01

    Part IIA of the Environmental Protection Act 1990 requires environmental regulators to assess the risk of contaminants leaching from soils into groundwater (DETR, 1999). This newly introduced legislation assumes a link between soil and groundwater chemistry, in which rainwater leaches contaminants from soil into the saturated zone. As the toxicity of both groundwater and overlying soils is dependent upon the chemicals present, their partitioning and their bioavailability, similar patterns of soil, leachates and groundwater toxicity should be observed at contaminated sites. Soil and groundwater samples were collected from different contaminated land sites in an urban area, and used to determine relationships between soil chemistry and toxicity, mobility of contaminants, and groundwater chemistry and toxicity. Soils were leached using water to mimic rainfall, and both the soils and leachates tested using bioassays. Soil bioassays were carried out using Eisenia fetida, whilst groundwater and leachates were tested using the Microtox test system and Daphnia magna 48 h acute tests. Analysis of the bioassay responses demonstrated that a number of the samples were toxic to test organisms, however, there were no significant statistical relationships between soil, groundwater and leachate toxicity. Nor were there significant correlations between soil, leachates and groundwater chemistry.

  2. Groundwater air stripping: Effect on water toxicity

    SciTech Connect

    Eldridge, R.B.; Simpson, C.W.; Elliott, D.J.

    1995-02-01

    An air stripping unit was designed to reduce groundwater hydrocarbon content and biotoxicity to acceptable levels. A pilot plant study was conducted to determine the water treatability and to optimize the commercial unit design conditions. A measurement of the pilot plant effluent toxicity was obtained from {open_quotes}Microtox{close_quotes} analysis and rigorous bio-assays. These results indicated that reduction of the water hydrocarbon content to permitted discharge limits was accompanied by the elimination of water toxicity. The Onda mass transfer model was used to prepare the commercial unit design. A post-installation evaluation indicated that the model gave a good representation of the commercial unit performance. Toxicity reductions observed in the pilot plant were also observed in the commercial unit. 3 refs., 5 figs., 3 tabs.

  3. Air stripping & photocatalytic oxidation: A winning team for groundwater remediation

    SciTech Connect

    Kittrell, J.R.; Quinlan, C.W.

    1995-09-01

    The Dover AFB Groundwater Reclamation Project demonstrated advanced technologies to control groundwater contamination, including comparisons of traditional countercurrent air atrippers to a crossflow air stripping technology. Another demonstration involved an advanced photocatalytic VOC destruction technology, which operates on the effluent air from the stripper. The combination of air stripping and photocatalytic destruction was shown to be effective for remediation of groundwater contaminated with chlorinated organic compounds, both because of its low cost and its ability to prevent toxic air emissions. A detailed performance comparison of stripper designs shows that the crossflow air stripper design was comparable in effectiveness to the conventional countercurrent air stripper at high air-to-water ratios, but at a substantially lower pressure drop.

  4. In-situ remediation system for groundwater and soils

    DOEpatents

    Corey, J.C.; Kaback, D.S.; Looney, B.B.

    1991-01-01

    The present invention relates to a system for in-situ remediation of contaminated groundwater and soil. In particular the present invention relates to stabilizing toxic metals in groundwater and soil. The United States Government has rights in this invention pursuant to Contract No. DE-AC09-89SR18035 between the US Department of Energy and Westinghouse Savannah River Company.

  5. Fate of synthetic organic chemicals in soil-groundwater systems.

    PubMed

    Pancorbo, O C; Varney, T C

    1986-04-01

    Land disposal of municipal, industrial and agricultural wastes often leads to soil and groundwater contamination with synthetic organic chemicals. In this review, the fate of such organics in soils and the subsurface environment is discussed. In particular, the biodegradation of organic compounds in soils and the subsurface region, as well as the sorption of these compounds to soils is emphasized. Due to the disastrous impact of groundwater contamination on a community and the great cost of restoring a contaminated aquifer, a case is made for concentrating future efforts on isolating potential sources of groundwater contamination and instituting appropriate control measures.

  6. Control of aromatic-waste air streams by soil bioreactors

    SciTech Connect

    Miller, D.E.; Canter, L.W.

    1991-01-01

    Contamination of groundwater resources is a serious environmental problem which is continuing to increase in occurrence in the United States. It has been reported that leaking underground gasoline storage tanks may pose the most serious threat of all sources of groundwater contamination. Gasolines are comprised of a variety of aliphatic and aromatic hydrocarbons. The aromatic portion consists primarily of benzene, toluene, ethylbenzene, and xylenes (BTEX compounds). BTEX compounds are also among the most frequency identified substances at Superfund sites. Pump and treat well systems are the most common and frequently used technique for aquifer restoration. Treatment is often in the form of air stripping to remove the volatile components from the contaminated water. Additionally, soil ventilation processes have been used to remove volatile components from the vadose zone. Both air stripping and soil ventilation produce a waste gas stream containing volatile compounds which is normally treated by carbon adsorption or incineration. Both treatment processes require a substantial capital investment and continual operation and maintenance expenditures. The objective of the study was to examine the potential of using soil bioreactors to treat a waste gas stream produced by air stripping or soil ventilation process. Previous studies have shown that various hydrocarbons can be successfully treated with soils. The study examined the removal of BTEX compounds within soil columns and the influence of soil type, inlet concentration, and inlet flow rate on the removal efficiency.

  7. Hot spot formation of chloroform in forest soils caused pollution of groundwater

    NASA Astrophysics Data System (ADS)

    Jacobsen, Ole S.; Albers, Christian N.; Laier, Troels; Hunkeler, Daniel

    2015-04-01

    High concentration of chloroform in groundwater is usually attributed to anthropogenic input, but we have found that the groundwater beneath some pristine areas contained chloroform from 1 - 10 µg/L. Groundwater containing chloroform that exceeds 1 µg/L could not be used for drinking water according to Danish regulations. The strict demands on groundwater quality may have to be taken into account when decisions are made regarding the change of land use in order to protect major recharge areas from pollution with nitrate and pesticides resulting from high-yield agriculture production. The terrestrial environment and especially hot spots in forest soils seem to be important contributors to apparent pollution of groundwater with chloroform. We performed a field study to investigate concentration and fluxes of chloroform to the groundwater from in four coniferous forests in order to increase knowledge on the hot spot formation and fate of natural chloroform. We investigated four stations over a period of several years in order to measure the net-formation of chloroform. Field measurements soil air concentrations of chloroform were monitored in five soil profiles down to the groundwater table. Meteorological data were recorded at all stations In the hotspots up to 120 ppbv was found in soil air under the spruce forest, to be compared to an ambient atmospheric concentration of 0.02 ppbv. The concentration of chloroform in soil air showed seasonal variation with a maximum in August-September. The chloroform concentration decreased with depth in all profiles during the summer half-year to about 20 % of concentration in the production layer. However, the concentration is still high enough to give an equilibrium concentration in the upper groundwater of 1-10 µg/L. Stable carbon isotopic analyses of chloroform from the uppermost groundwater in different parts of the forests and from soil water showed values from δ13C = -13 ‰ to -27 ‰, corresponding to the ratio in

  8. Use of Additives in Bioremediation of Contaminated Groundwater and Soil

    EPA Science Inventory

    This chapter reviews application of additives used in bioremediation of chlorinated solvents and fuels for groundwater and soil remediation. Soluble carbon substrates are applicable to most site conditions except aquifers with very high or very low groundwater flow. Slow-release ...

  9. Evaluation of soil temperature effect on herbicide leaching potential into groundwater in the Brazilian Cerrado.

    PubMed

    Paraíba, Lourival Costa; Cerdeira, Antonio Luiz; da Silva, Enio Fraga; Martins, João Souza; Coutinho, Heitor Luiz da Costa

    2003-12-01

    The effect of annual variations in the daily average soil temperatures, at different depths, on the calculation of pesticide leaching potential indices is presented. This index can be applied to assess the risk of groundwater contamination by a pesticide. It considers the effects of water table depth, daily recharge net rate, pesticide sorption coefficient, and degradation rate of the pesticide in the soil. The leaching potential index is frequently used as a screening indicator in pesticide groundwater contamination studies, and the temperature effect involved in its calculation is usually not considered. It is well known that soil temperature affects pesticide degradation rates, air-water partition coefficient, and water-soil partition coefficient. These three parameters are components of the attenuation and retardation factors, as well as the leaching potential index, and contribute to determine pesticide behavior in the environment. The Arrhenius, van't Hoff, and Clausius-Clapeyron equations were used in this work to estimate the soil temperature effect on pesticide degradation rate, air-water partition coefficient, and water-soil partition coefficient, respectively. The relationship between leaching potential index and soil temperature at different depths is presented and aids in the understanding of how potential pesticide groundwater contamination varies on different climatic conditions. Numerical results will be presented for 31 herbicides known to be used in corn and soybean crops grown on the municipality of São Gabriel do Oeste, Mato Grosso do Sul State, Brazil.

  10. USEPA'S RESEARCH PROGRAM ON REMEDIATION AND CONTAINMENT OF ARSENIC AND MERCURY IN SOILS, INDUSTRIAL WASTES, AND GROUNDWATER

    EPA Science Inventory

    In the U.S. and around the world, mercury and arsenic contaminated soils, industrial wastes, and groundwater are difficult to effectively and cheaply remediate and contain. Mercury is a serious health concern and has been identified as a contaminant in the air, soil, sediment, su...

  11. Connecting carbon and nitrogen storage in rural wetland soil to groundwater abstraction for urban water supply.

    PubMed

    Lewis, David Bruce; Feit, Sharon J

    2015-04-01

    We investigated whether groundwater abstraction for urban water supply diminishes the storage of carbon (C), nitrogen (N), and organic matter in the soil of rural wetlands. Wetland soil organic matter (SOM) benefits air and water quality by sequestering large masses of C and N. Yet, the accumulation of wetland SOM depends on soil inundation, so we hypothesized that groundwater abstraction would diminish stocks of SOM, C, and N in wetland soils. Predictions of this hypothesis were tested in two types of subtropical, depressional-basin wetland: forested swamps and herbaceous-vegetation marshes. In west-central Florida, >650 ML groundwater day(-1) are abstracted for use primarily in the Tampa Bay metropolis. At higher abstraction volumes, water tables were lower and wetlands had shorter hydroperiods (less time inundated). In turn, wetlands with shorter hydroperiods had 50-60% less SOM, C, and N per kg soil. In swamps, SOM loss caused soil bulk density to double, so areal soil C and N storage per m(2) through 30.5 cm depth was diminished by 25-30% in short-hydroperiod swamps. In herbaceous-vegetation marshes, short hydroperiods caused a sharper decline in N than in C. Soil organic matter, C, and N pools were not correlated with soil texture or with wetland draining-reflooding frequency. Many years of shortened hydroperiod were probably required to diminish soil organic matter, C, and N pools by the magnitudes we observed. This diminution might have occurred decades ago, but could be maintained contemporarily by the failure each year of chronically drained soils to retain new organic matter inputs. In sum, our study attributes the contraction of hydroperiod and loss of soil organic matter, C, and N from rural wetlands to groundwater abstraction performed largely for urban water supply, revealing teleconnections between rural ecosystem change and urban resource demand.

  12. [Assessment of TVOC and odor in the remediation site of contaminated soil and groundwater using electronic nose].

    PubMed

    Tian, Xiu-Ying; Cai, Qiang; Liu, Rui; Zhang, Yong-Ming

    2013-02-01

    According to the conditions of a contaminated soil and groundwater remediation site in Shanghai, the self-built electronic nose was applied to detect VOCs and odor of previously remedied soil and groundwater, remedying soil and groundwater, and the air above and around the site. Combining the formula of TPI and OPI, the value of each point was got and was shown in figures. Results showed: 1. Comparing the determination results of previously remedied with remedying contaminated soil and groundwater, the concentration of TVOC and odor was overall declined. The result was consistent with the fact. The detection result of electronic nose was proved to be right; 2. In the remediation process of soil and groundwater, the volatilization of VOCs and odor was inflected by temperature and works of crushing, adding medicine and turning the soil on time. The concentration showed a trend of overall decline with stage rising, so the electronic noses can be used for dynamic monitoring of the whole remediation process; 3. Combined with the GIS, the electronic noses can preliminary assess space pollution situation caused by the remediation of contaminated soil and groundwater and the influence on the residence in the surrounding region. However, further study on the refined classification of the impact degree is needed.

  13. Flow Of Groundwater From Soil To Crystalline Rock

    NASA Astrophysics Data System (ADS)

    Olofsson, B.

    1994-03-01

    Knowledge of groundwater flow from soil or surface water to crystalline bedrock has usually been derived from indirect studies of drawdown in soil due to underground constructions, as well as from analysis of water chemistry and from tracer experiments. Infiltration into the bedrock occurs at specific sites where suitable combinations of geological and hydrological variables exist. Flow from soil to rock in the saturated zone occurs where conductors in the bedrock, such as fractures and fracture zones, are hydraulically connected to a groundwater reservoir in permeable soil or to horizons of permeable and constructive material in heterogeneous soil. Of particular importance for infiltration are the hydraulic conditions of the contact zone between soil and rock. A thin layer of silt on the bedrock surface often blocks the water flow. The micro-topography of the bedrock surface is important since fracture zones usually give depressions in the surface, in which accumulations of sorted and conductive material often can be found. A strong heterogeneity in the infiltration from soil to rock is evidenced by statistical analyses of the flow related to various geological and hydrogeological variables, as well as from analyses of groundwater chemistry and tracer experiments. In order to estimate the infiltration from soil to rock and to carry out mathematical modelling of the groundwater flow, it is necessary to have a good knowledge of the hydraulic conditions of the superficial rock and soil as well as of the conditions at the soil/bedrock contact zone. Information on the saturated flow from soil to rock is essential for calculation of water budgets, for assessments of spread of pollutants and for estimations of leakage into underground constructions.

  14. Air stripping of organics from groundwater

    SciTech Connect

    Harrison, D.P.; Valsaraj, K.T.; Wetzel, D.M. . Dept. of Chemical Engineering)

    1993-01-01

    As awareness of the problem of contaminated ground water increases, the demand for reliable and cost-effective treatment processes will also increase. Although a number of treatment options exist or are under development, air stripping using counter current flow in packed columns is the current technology of choice in many situations. This paper reviews the basic principles of packed-column design and defines the limits of counter current contacting when applied to situations in which the resistance to mass transfer in the gas phase is important. The cascade crossflow configuration allows water and air flow to be varied independently, providing added design flexibility. Reductions in pressure drop by as much as two orders of magnitude result in stable column operation at air and water flow rates which would cause flooding in a counter current column. Mass transfer efficiencies comparable to, and in some cases greater than, counter current operation have been measured. Experimental results for cascade crossflow air stripping of 1,2-dichloroethane and methyl ethyl ketone are presented. The gas-phase, mass-transfer resistance is important for both compounds due to their small Henry's constants, 1,2-dichloroethane is considered to be difficult to strip using counter current contacting, while high efficiency air stripping of methyl ethyl ketone is impractical at ambient temperature.

  15. Sources of arsenic and fluoride in highly contaminated soils causing groundwater contamination in Punjab, Pakistan.

    PubMed

    Farooqi, Abida; Masuda, Harue; Siddiqui, Rehan; Naseem, Muhammad

    2009-05-01

    Highly contaminated groundwater, with arsenic (As) and fluoride (F(-)) concentrations of up to 2.4 and 22.8 mg/L, respectively, has been traced to anthropogenic inputs to the soil. In the present study, samples collected from the soil surface and sediments from the most heavily polluted area of Punjab were analyzed to determine the F(-) and As distribution in the soil. The surface soils mainly comprise permeable aeolian sediment on a Pleistocene terrace and layers of sand and silt on an alluvial flood plain. Although the alluvial sediments contain low levels of F, the terrace soils contain high concentrations of soluble F(-) (maximum, 16 mg/kg; mean, 4 mg/kg; pH > 8.0). Three anthropogenic sources were identified as fertilizers, combusted coal, and industrial waste, with phosphate fertilizer being the most significance source of F(-) accumulated in the soil. The mean concentration of As in the surface soil samples was 10.2 mg/kg, with the highest concentration being 35 mg/kg. The presence of high levels of As in the surface soil implies the contribution of air pollutants derived from coal combustion and the use of fertilizers. Intensive mineral weathering under oxidizing conditions produces highly alkaline water that dissolves the F(-) and As adsorbed on the soil, thus releasing it into the local groundwater.

  16. Sources of arsenic and fluoride in highly contaminated soils causing groundwater contamination in Punjab, Pakistan

    SciTech Connect

    Farooqi, A.; Masuda, H.; Siddiqui, R.; Naseem, M.

    2009-05-15

    Highly contaminated groundwater, with arsenic (As) and fluoride (F{sup -}) concentrations of up to 2.4 and 22.8 mg/L, respectively, has been traced to anthropogenic inputs to the soil. In the present study, samples collected from the soil surface and sediments from the most heavily polluted area of Punjab were analyzed to determine the F{sup -} and As distribution in the soil. The surface soils mainly comprise permeable aeolian sediment on a Pleistocene terrace and layers of sand and silt on an alluvial flood plain. Although the alluvial sediments contain low levels of F, the terrace soils contain high concentrations of soluble F{sup -} (maximum, 16 mg/kg; mean, 4 mg/kg; pH > 8.0). Three anthropogenic sources were identified as fertilizers, combusted coal, and industrial waste, with phosphate fertilizer being the most significance source of F{sup -} accumulated in the soil. The mean concentration of As in the surface soil samples was 10.2 mg/kg, with the highest concentration being 35 mg/kg. The presence of high levels of As in the surface soil implies the contribution of air pollutants derived from coal combustion and the use of fertilizers. Intensive mineral weathering under oxidizing conditions produces highly alkaline water that dissolves the F{sup -} and As adsorbed on the soil, thus releasing it into the local groundwater.

  17. Lindane biodegradation in groundwater using semi-continuous soil columns

    SciTech Connect

    LaPat-Polasko, L.T.; Lazarr, N.C.; Reker, M.A.

    1995-12-31

    To evaluate the potential for bioremediation of various isomers of benzene hexachloride (BHC) including lindane (gamma BHC)-contaminated groundwater, a bench-scale study was conducted using site groundwater and soil collected from a chemical manufacturing facility located in southwest Missouri. Three soil columns were prepared to evaluate various conditions under which contaminant biodegredation is known to occur: Column 1 (the hydrogen peroxide and nutrient column) received site groundwater, hydrogen peroxide (an oxygen source to promote aerobic conditions) and ammonium polyphosphate (nutrients); Column 2 received site groundwater, nutrients and sodium sulfite (a reductant to promote anaerobic conditions); and Column 3 received the same amendments as Column 1 but under sterile conditions. Column 3 was used to evaluate abiotic losses of contaminants. The indigenous soil and/or groundwater microbial population removed more than 99 percent of the BHC isomers present in the hydrogen peroxide and nutrient column influent in 24 hours. Abiotic losses of contaminants were less than 20 percent after initial column exchanges based on the results of sterile column data. Anaerobic conditions were not as conducive to contaminant degradation. During the 24-hour exchange periods, less than 80 percent BHC removal was observed in the groundwater effluents from the anaerobic column.

  18. Assessing soil and groundwater contamination in a metropolitan redevelopment project.

    PubMed

    Yun, Junki; Lee, Ju Young; Khim, Jeehyeong; Ji, Won Hyun

    2013-08-01

    The purpose of this study was to assess contaminated soil and groundwater for the urban redevelopment of a rapid transit railway and a new mega-shopping area. Contaminated soil and groundwater may interfere with the progress of this project, and residents and shoppers may be exposed to human health risks. The study area has been remediated after application of first remediation technologies. Of the entire area, several sites were still contaminated by waste materials and petroleum. For zinc (Zn) contamination, high Zn concentrations were detected because waste materials were disposed in the entire area. For petroleum contamination, high total petroleum hydrocarbon (TPH) and hydrocarbon degrading microbe concentrations were observed at the depth of 7 m because the underground petroleum storage tank had previously been located at this site. Correlation results suggest that TPH (soil) concentration is still related with TPH (groundwater) concentration. The relationship is taken into account in the Spearman coefficient (α). PMID:23307052

  19. Assessing soil and groundwater contamination in a metropolitan redevelopment project.

    PubMed

    Yun, Junki; Lee, Ju Young; Khim, Jeehyeong; Ji, Won Hyun

    2013-08-01

    The purpose of this study was to assess contaminated soil and groundwater for the urban redevelopment of a rapid transit railway and a new mega-shopping area. Contaminated soil and groundwater may interfere with the progress of this project, and residents and shoppers may be exposed to human health risks. The study area has been remediated after application of first remediation technologies. Of the entire area, several sites were still contaminated by waste materials and petroleum. For zinc (Zn) contamination, high Zn concentrations were detected because waste materials were disposed in the entire area. For petroleum contamination, high total petroleum hydrocarbon (TPH) and hydrocarbon degrading microbe concentrations were observed at the depth of 7 m because the underground petroleum storage tank had previously been located at this site. Correlation results suggest that TPH (soil) concentration is still related with TPH (groundwater) concentration. The relationship is taken into account in the Spearman coefficient (α).

  20. Measurement of helium isotopes in soil gas as an indicator of tritium groundwater contamination.

    PubMed

    Olsen, Khris B; Dresel, P Evan; Evans, John C; McMahon, William J; Poreda, Robert

    2006-05-01

    The focus of this study was to define the shape and extent of tritium groundwater contamination emanating from a legacy burial ground and to identify vadose zone sources of tritium using helium isotopes (3He and 4He) in soil gas. Helium isotopes were measured in soil-gas samples collected from 70 sampling points around the perimeter and downgradient of a burial ground that contains buried radioactive solid waste. The soil-gas samples were analyzed for helium isotopes using rare gas mass spectrometry. 3He/4He ratios, reported as normalized to the air ratio (RA), were used to locate the tritium groundwater plume emanating from the burial ground. The 3He (excess) suggested that the general location of the tritium source is within the burial ground. This study clearly demonstrated the efficacy of the 3He method for application to similar sites elsewhere within the DOE weapons complex.

  1. GROUNDWATER AND SOIL REMEDIATION USING ELECTRICAL FIELD

    EPA Science Inventory

    Enhancements of contaminants removal and degradation in low permeability soils by electrical fields are achieved by the processes of electrical heating, electrokinetics, and electrochemical reactions. Electrical heating increases soil temperature resulting in the increase of cont...

  2. Spatial Variations of Soil Microbial Activities in Saline Groundwater-Irrigated Soil Ecosystem

    NASA Astrophysics Data System (ADS)

    Chen, Li-Juan; Feng, Qi; Li, Chang-Sheng; Song, You-Xi; Liu, Wei; Si, Jian-Hua; Zhang, Bao-Gui

    2016-05-01

    Spatial variations of soil microbial activities and its relationship with environmental factors are very important for estimating regional soil ecosystem function. Based on field samplings in a typical saline groundwater-irrigated region, spatial variations of soil microbial metabolic activities were investigated. Combined with groundwater quality analysis, the relationship between microbial activities and water salinity was also studied. The results demonstrated that moderate spatial heterogeneity of soil microbial activities presented under the total dissolved solids (TDS) of groundwater ranging from 0.23 to 12.24 g L-1. Groundwater salinity and microbial activities had almost opposite distribution characteristics: slight saline water was mainly distributed in west Baqu and south Quanshan, while severe saline and briny water were dominant in east Baqu and west Huqu; however, total AWCD was higher in the east-center and southwest of Baqu and east Huqu, while it was lower in east Baqu and northwest Huqu. The results of correlation analyses demonstrated that high-salinity groundwater irrigation had significantly adverse effects on soil microbial activities. Major ions Ca2+, Mg2+, Cl_, and SO4 2- in groundwater decisively influenced the results. Three carbon sources, carbohydrates, amines, and phenols, which had minor utilization rates in all irrigation districts, were extremely significantly affected by high-salinity groundwater irrigation. The results presented here offer an approach for diagnosing regional soil ecosystem function changes under saline water irrigation.

  3. Evaluation of soil-venting application. Ground-water issue

    SciTech Connect

    DiGiulio, D.C.

    1992-04-01

    The Regional Superfund Ground-Water Forum is a group of scientists, representing EPA's Regional Superfund Offices, organized to exchange up-to-date information related to ground-water remediation at Superfund sites. One of the major issues of concern to the Forum is the transport and fate of contaminants in soil and ground water as related to subsurface remediation. The ability of soil venting to inexpensively remove large amounts of volatile organic compounds (VOCs) from contaminated soils is well established. However, the time required using venting to remediate soils to low contaminant levels often required by state and federal regulators has not been adequately investigated. Discussion is presented to aid in evaluating the feasibility of venting application. Methods to optimize venting application are also discussed.

  4. Biological reduction of uranium in groundwater and subsurface soil.

    PubMed

    Abdelouas, A; Lutze, W; Gong, W; Nuttall, E H; Strietelmeier, B A; Travis, B J

    2000-04-24

    Biological reduction of uranium is one of the techniques currently studied for in situ remediation of groundwater and subsurface soil. We investigated U(VI) reduction in groundwaters and soils of different origin to verify the presence of bacteria capable of U(VI) reduction. The groundwaters originated from mill tailings sites with U concentrations as high as 50 mg/l, and from other sites where uranium is not a contaminant, but was added in the laboratory to reach concentrations up to 11 mg/l. All waters contained nitrate and sulfate. After oxygen and nitrate reduction, U(VI) was reduced by sulfate-reducing bacteria, whose growth was stimulated by ethanol and trimetaphosphate. Uranium precipitated as hydrated uraninite (UO2 x xH2O). In the course of reduction of U(VI), Mn(IV) and Fe(III) from the soil were reduced as well. During uraninite precipitation a comparatively large mass of iron sulfides formed and served as a redox buffer. If the excess of iron sulfide is large enough, uraninite will not be oxidized by oxygenated groundwater. We show that bacteria capable of reducing U(VI) to U(IV) are ubiquitous in nature. The uranium reducers are primarily sulfate reducers and are stimulated by adding nutrients to the groundwater.

  5. Soil, groundwater cleanup takes the gamble out of casino operation

    SciTech Connect

    Not Available

    1993-02-01

    Colorado's rich stores of gold and silver sparked development of towns like Black Hawk and Central City in the 1890s. Today, these communities are the homes of limited-stakes gaming operations. However casino operators are discovering that having gold and silver underground in the form of tailings is not as desirable as collecting it aboveground in slot machines. A unique environmental engineering approach allowed construction of two new casinos and reclamation of the tailings, as well as cleanup of petroleum-saturated soils and groundwater. A treatment system was designed and constructed to treat groundwater at the Black Hawk site. The most economical alternative for disposing treated groundwater was to discharge it into nearby North Clear Creek. An NPDES permit was obtained requiring treatment of the groundwater for petroleum, heavy metals and pH before discharging it.

  6. Record of Decision Tank Farm Soil and INTEC Groundwater

    SciTech Connect

    L. S. Cahn

    2007-05-01

    This decision document presents the selected remedy for Operable Unit (OU) 3-14 tank farm soil and groundwater at the Idaho Nuclear Technology and Engineering Center (INTEC), which is located on the Idaho National Laboratory (INL) Site. The tank farm was initially evaluated in the OU 3-13 Record of Decision (ROD), and it was determined that additional information was needed to make a final decision. Additional information has been obtained on the nature and extent of contamination in the tank farm and on the impact of groundwater. The selected remedy was chosen in accordance with the Comprehensive Environmental Response, Liability and Compensation Act of 1980 (CERCLA) (42 USC 9601 et seq.), as amended by the Superfund Amendments and Reauthorization Act of 1986 (Public Law 99-499) and the National Oil and Hazardous Substances Pollution Contingency Plan (40 CFR 300). The selected remedy is intended to be the final action for tank far soil and groundwater at INTEC.

  7. PRACTICAL DIAGNOSIS OF BIOSTIMULATION FOR VOC CONTAMINATED SOIL AND GROUNDWATER

    NASA Astrophysics Data System (ADS)

    Suzuki, Keiichi; Ando, Takuya; Ito, Yoshitaka; Sato, Takeshi

    Biostimulation has been widely used as a remediation of soil and groundwater contaminated by chlorinated volatile organic compounds (VOC). The chemical and biological systems in actual field are so complicated that it is hard to know the mathematical modeling parameters prior to laboratory tests using contaminated soil and groundwater sampled from specific site. The paper addresses an diagnostic method to evaluate the parameters controlling the lag time an d the chemical reaction rate which are essential to predict efficiency of biostimulation in actual field. In this paper, laboratory test results of thirtyseven sites are stochastically reanalyzed to make clear the dependency of the lag time and the chemical reaction rate on groundwater quality indices, such as DO, ORP, pH, etc.

  8. Soil amendment with olive mill wastes: impact on groundwater.

    PubMed

    Caputo, Maria Clementina; De Girolamo, Anna Maria; Volpe, Angela

    2013-12-15

    Two sets of soil lysimeters were amended with solid and liquid olive mill wastes and the composition of leachate was analysed. Five treatments were carried out using: olive mill wastewater (OMW) at two different rates (80 and 320 m(3)/ha); OMW pre-treated by catalytical digestion with MnO2; compost obtained by exhausted olive pomace; freshwater as the control. Electric conductivity, pH, potassium, total polyphenols and nitrates were monitored in the leachate as indexes of potential groundwater contamination. The study demonstrated that the impact of all the selected amendments on groundwater was the minimum. OMW was safely applied to soil even at four times the rate allowed by the Italian law, and pre-treatment by catalytical digestion was not necessary to further reduce the impact on groundwater. The application of olive pomace compost was equally safe.

  9. Air permeability and trapped-air content in two soils

    USGS Publications Warehouse

    Stonestrom, D.A.; Rubin, J.

    1989-01-01

    To improve understanding of hysteretic air permeability relations, a need exists for data on the water content dependence of air permeability, matric pressure, and air trapping (especially for wetting-drying cycles). To obtain these data, a special instrument was designed. The instrument is a combination of a gas permeameter (for air permeability determination), a suction plate apparatus (for retentivity curve determination), and an air pycnometer (for trapped-air-volume determination). This design allowed values of air permeability, matric pressure, and air trapping to be codetermined, i.e., determined at the same values of water content using the same sample and the same inflow-outflow boundaries. Such data were obtained for two nonswelling soils. -from Authors

  10. A Preliminary Study for Chemical Ranking System in Terms of Soil and Groundwater Contamination by Chemical Accidents

    NASA Astrophysics Data System (ADS)

    Park, J.; Jeong, Y. C.; Kim, K. E.; Lee, D.; Yoo, K.; Kim, J.; Hwang, S.

    2015-12-01

    A variety of chemicals could affect human health and ecosystems by chemical accidents such as fire, explosion, and/or spill. Chemical accidents make chemicals spread to the environment via various routes such as dispersion into ambient air, soil, and surface/ground water media. Especially, soil and groundwater contamination by chemical accidents become a secondary source to have a long term effect on human health and environment. Strength of long term effect by soil and groundwater contamination depends largely on inherent characteristics of a chemical and its fate in soil and groundwater. Therefore, in this study, we developed a framework on how to determine what kind of chemicals is more important in management scheme in terms of soil and groundwater contamination during chemical accidents. We ranked approximately fifty chemicals using this framework which takes into account an exposure into soil and groundwater, toxicity, persistence, and bioaccumulation of a chemical. This framework helps to prepare systematically the management plan for chemical related facilities. Furthermore, results from our study can make a policy maker have interests in highly ranked chemicals and facilities.

  11. A new separation and treatment method for soil and groundwater restoration

    SciTech Connect

    Hitchens, G.D.

    1997-10-01

    Soil and groundwater contamination by organic compounds is a widespread environmental pollution problem. In many cases, contaminated soil is excavated and transported to a landfill or is incinerated to remove contaminants. These remediation practices are expensive, environmentally disruptive, require extensive permitting, and only move contamination from one location to another. Onsite and in situ treatment techniques offer a safer, more cost-effective, and permanent solution. Many soil and groundwater contaminants are highly volatile, enabling the use of methods such as in situ vacuum extraction and air injection for their removal. However, these methods are often difficult to use because of slow volatilization rates and the lack of effective methods to treat the extracted hazardous material. This Phase I Small Business Innovation Research program focuses on developing an in situ soil and groundwater remediation technique that is effective against volatile as well as nonvolatile compounds and that will shorten treatment times. The technique forms the basis of a new catalytic process to degrade extracted contaminants onsite. Key hardware elements on which the new technique is based have been proven in preliminary research. The method has a high potential for public and regulatory acceptance because of its low environment impact.

  12. Groundwater remediation engineering sparging using acetylene--study on the flow distribution of air.

    PubMed

    Zheng, Yan-Mei; Zhang, Ying; Huang, Guo-Qiang; Jiang, Bin; Li, Xin-Gang

    2005-01-01

    Air sparging (AS) is an emerging method to remove VOCs from saturated soils and groundwater. Air sparging performance highly depends on the air distribution resulting in the aquifer. In order to study gas flow characterization, a two-dimensional experimental chamber was designed and installed. In addition, the method by using acetylene as the tracer to directly image the gas distribution results of AS process has been put forward. Experiments were performed with different injected gas flow rates. The gas flow patterns were found to depend significantly on the injected gas flow rate, and the characterization of gas flow distributions in porous media was very different from the acetylene tracing study. Lower and higher gas flow rates generally yield more irregular in shape and less effective gas distributions.

  13. Regional scale assessment of soil predictors of groundwater phosphate (P) levels in acidic sandy agricultural soils

    NASA Astrophysics Data System (ADS)

    Mabilde, Lisa

    2016-04-01

    Possible factors affecting the leaching of P to the groundwater in the Belgian sandy area are examined via regression analysis. The main objective is to investigate the dependency of phreatic groundwater phosphate concentrations (Flemish VMM monitoring net, monitoring period 2010-2013) on soil phosphate saturation degree (PSD) (1994-1997 mapping for Flemish Land Agency) (n = 1032). Additionally explored parameters include: depth distributions of Fe- and Al-oxides, sorbed P and phosphate sorption capacity (PSC) and soil pH. Interpolated data of these soil parameters in 3 depth layers (0-30, 30-60, 60-90 cm) were generated by ordinary kriging. Secondly, we assessed the significance of other edaphic factors potentially controlling the groundwater P: topsoil organic carbon content (OC %), soil clay content and fluctuation of the groundwater table. Overall, the mean PSD halved with each 30 cm depth layer (56 > 24 > 13 %) and was correlated to groundwater PO43‑ level. The statistical significance of the correlation with groundwater PO43‑ concentrations increased with depth layer. The poor correlation (R2 = 0.01) between PSD and groundwater phosphate concentration indicates that many factors, other than soil P status, control the transport of P from soil solution to the groundwater in Belgian sandy soils. A significant (P<0.01) positive non-linear relationship was found between groundwater PO43‑concentration and pHKCl in all three studied depth layers, again increasingly with depth. Within the pH range of the 30-60 cm layer (pHKCl 4.0-5.7) PO4‑ solubility should increase with pH. Elevated soil OC levels surprisingly co-occurred with low groundwater PO43‑ concentrations (r = -0.18, P<0.01, n = 191). Groundwater PO43‑ was furthermore significantly and positively correlated to clay % in both the 0-15 cm (r = 0.15, τ = 0.25, P<0.01, n = 1032) and 60-90 cm (r = 0.13, τ = 0.20, P<0.01, n = 1032) depth increments. These positive correlations were unexpected and

  14. Regional scale assessment of soil predictors of groundwater phosphate (P) levels in acidic sandy agricultural soils

    NASA Astrophysics Data System (ADS)

    Mabilde, Lisa

    2016-04-01

    Possible factors affecting the leaching of P to the groundwater in the Belgian sandy area are examined via regression analysis. The main objective is to investigate the dependency of phreatic groundwater phosphate concentrations (Flemish VMM monitoring net, monitoring period 2010-2013) on soil phosphate saturation degree (PSD) (1994-1997 mapping for Flemish Land Agency) (n = 1032). Additionally explored parameters include: depth distributions of Fe- and Al-oxides, sorbed P and phosphate sorption capacity (PSC) and soil pH. Interpolated data of these soil parameters in 3 depth layers (0-30, 30-60, 60-90 cm) were generated by ordinary kriging. Secondly, we assessed the significance of other edaphic factors potentially controlling the groundwater P: topsoil organic carbon content (OC %), soil clay content and fluctuation of the groundwater table. Overall, the mean PSD halved with each 30 cm depth layer (56 > 24 > 13 %) and was correlated to groundwater PO43- level. The statistical significance of the correlation with groundwater PO43- concentrations increased with depth layer. The poor correlation (R2 = 0.01) between PSD and groundwater phosphate concentration indicates that many factors, other than soil P status, control the transport of P from soil solution to the groundwater in Belgian sandy soils. A significant (P<0.01) positive non-linear relationship was found between groundwater PO43-concentration and pHKCl in all three studied depth layers, again increasingly with depth. Within the pH range of the 30-60 cm layer (pHKCl 4.0-5.7) PO4- solubility should increase with pH. Elevated soil OC levels surprisingly co-occurred with low groundwater PO43- concentrations (r = -0.18, P<0.01, n = 191). Groundwater PO43- was furthermore significantly and positively correlated to clay % in both the 0-15 cm (r = 0.15, τ = 0.25, P<0.01, n = 1032) and 60-90 cm (r = 0.13, τ = 0.20, P<0.01, n = 1032) depth increments. These positive correlations were unexpected and could be

  15. Soil air and soil flux measurements of 222Radon and CO2: A soil flux parametrization at Lutjewad (NL)

    NASA Astrophysics Data System (ADS)

    Neubert, R. E. M.; Kettner, E.; Palstra, S. W. L.; Hoekman, S.; van der Graaf, E. R.

    2009-04-01

    Atmospheric 222Radon concentration measurements are used as a valuable transport tracer verifying the transport part of Carbon Cycle and Greenhouse Gas models. The production rate of the radioactive noble gas 222Radon (T1•2 = 3.8 days) by radioactive decay of 226Radium in the soil is constant, the absolute quantity depending on the local soil Radium concentration. The flux of 222Radon to the atmosphere (the soil exhalation, or effective atmospheric production rate), however, is not constant. It strongly depends on soil texture, soil humidity, precipitation and other parameters, but is nearly constant if these parameters stay unchanged. Recently, an effort has been done to predict this flux rate with widely available γ-dosimetry measurements (Szegvary et al., Predicting terrestrial 222Rn-flux using gamma dose rate as a proxy, ACP 7, 2789-2795, 2007), but real 222Radon-flux measurements are sparse. 222Radon undergoes the same transport processes on the way from soil to atmosphere as any other soil-derived (greenhouse) gas. This makes 222Radon an ideal tracer to separate variations in e.g. soil CO2-production from changes in the soil-atmosphere CO2-transport, both being reflected in the total soil-atmosphere CO2-flux. At the atmospheric measurement site Lutjewad in the north of the Netherlands (53N24'18", 6E21'13", www.rug.nl/ees/onderzoek/cio/projecten/atmosphericgases) we started in 2006 with the measurements of the soil 222Radon and CO2 concentration through soil probes as well as the Radon and CO2 soil fluxes by means of an automatic soil chamber. While there are up to eight soil air measurements per day, the soil chamber is automatically closed twice per day. The station is situated directly on the Waddensea dike at an elevation of 1 m a.s.l. on seaclay soil. The groundwater table shows variations between 0.5 m and 2 m below terrain. From our measurements we find that in the dryer summer season, from April to July, the mean 222Radon-flux can be up to 40

  16. An analysis of trichloroethylene movement in groundwater at castle Air Force Base, California

    USGS Publications Warehouse

    Avon, L.; Bredehoeft, J.D.

    1989-01-01

    A trichloroethylene (TCE) plume has been identified in the groundwater under a U.S. Air Force Base in the Central Valley of California. An areal, two-dimensional numerical solute transport model indicates that the movement of TCE due to advection, dispersion, and linear sorption is simulated over a 25-year historic period. The model is used in several ways: (1) to estimate the extent of the plume; (2) to confirm the likely sources of contamination as suggested by a soil organic vapor survey of the site; and (3) to make predictions about future movement of the plume. Despite the noisy and incomplete data set, the model reproduces the general trends in contamination at a number of observation wells. The analysis indicates that soil organic vapor monitoring is an effective tool for identifying contaminant source locations. Leaky sewer pipes and underground tanks are the indicated pathways for TCE to have entered the groundwater system. The chemical mass balance indicates that a total of about 100 gallons of TCE - a relatively small amount of organic solvent - has created the observed groundwater plume. ?? 1989.

  17. [Simulation on remediation of benzene contaminated groundwater by air sparging].

    PubMed

    Fan, Yan-Ling; Jiang, Lin; Zhang, Dan; Zhong, Mao-Sheng; Jia, Xiao-Yang

    2012-11-01

    Air sparging (AS) is one of the in situ remedial technologies which are used in groundwater remediation for pollutions with volatile organic compounds (VOCs). At present, the field design of air sparging system was mainly based on experience due to the lack of field data. In order to obtain rational design parameters, the TMVOC module in the Petrasim software package, combined with field test results on a coking plant in Beijing, is used to optimize the design parameters and simulate the remediation process. The pilot test showed that the optimal injection rate was 23.2 m3 x h(-1), while the optimal radius of influence (ROI) was 5 m. The simulation results revealed that the pressure response simulated by the model matched well with the field test results, which indicated a good representation of the simulation. The optimization results indicated that the optimal injection location was at the bottom of the aquifer. Furthermore, simulated at the optimized injection location, the optimal injection rate was 20 m3 x h(-1), which was in accordance with the field test result. Besides, 3 m was the optimal ROI, less than the field test results, and the main reason was that field test reflected the flow behavior at the upper space of groundwater and unsaturated area, in which the width of flow increased rapidly, and became bigger than the actual one. With the above optimized operation parameters, in addition to the hydro-geological parameters measured on site, the model simulation result revealed that 90 days were needed to remediate the benzene from 371 000 microg x L(-1) to 1 microg x L(-1) for the site, and that the opeation model in which the injection wells were progressively turned off once the groundwater around them was "clean" was better than the one in which all the wells were kept operating throughout the remediation process.

  18. Air stripping VOCs from groundwater: Process design considerations

    SciTech Connect

    Ball, B.R.; Edwards, M.D. )

    1992-02-01

    Considerations for evaluating and designing the air stripping process are presented by case study. The case study involves the design of an air stripping process to remediate groundwater contaminated with volatile organic compounds (VOCs) at a National Priorities List site in Tacoma, WA. Design objectives included developing a tower with minimum volume and energy requirements while complying with discharge air and water quality standards. A two-phase resistance model using Onda Correlations to determine liquid- and gas-phase mass transfer coefficients was used to assist in the evaluation and design. Considerations for applying the two-phase resistance model to air stripping tower design are presented. The ability of the model to simulate process performance is demonstrated by comparison with actual data for 11 priority pollutant list VOCs evaluated during an onsite pilot study. Design procedures with which to develop a tower with minimum volume and energy requirements are described. Other considerations involving the evaluation of VOC emissions and the precipitation and buildup of inorganic constituents within the internal packing media are described.

  19. Groundwater

    USGS Publications Warehouse

    Stonestrom, David A.; Wohl, Ellen E.

    2016-01-01

    , including nutrients and dissolved oxygen. Groundwater withdrawals can negatively impact riparian habitats by depriving ecosystems of adequate fresh water and fragmenting communities when streams go dry. Biochemical reactions in shallow groundwater can remove anthropogenically elevated nitrogen compounds and reduce—but only to a point—the greening of waterways and shorelines with periphyton and harmful algal blooms. Groundwater extraction for beneficial use is increasingly limited by water-quality constraints imposed by naturally occurring and introduced substances. Overdrafting can cause land-surface subsidence, damaging buildings and roads and disrupting canals, sewers, and other gravity-flow conveyances. Increases in groundwater levels can cause soil salinization in dry regions and erosive sapping and flooding in wet regions. Coastal saltwater intrusion, groundwater flooding, salinization associated with groundwater-irrigated agriculture, induced seismicity from injected wastes, and the detrimental impacts of groundwater depletion are among the major environmental challenges of our time.

  20. Remediation of saturated soil contaminated with petroleum products using air sparging with thermal enhancement.

    PubMed

    Mohamed, A M I; El-menshawy, Nabil; Saif, Amany M

    2007-05-01

    Pollutants in the form of non-aqueous phase liquids (NAPLs), such as petroleum products, pose a serious threat to the soil and groundwater. A mathematical model was derived to study the unsteady pollutant concentrations through water saturated contaminated soil under air sparging conditions for different NAPLs and soil properties. The comparison between the numerical model results and the published experimental results showed acceptable agreement. Furthermore, an experimental study was conducted to remove NAPLs from the contaminated soil using the sparging air technique, considering the sparging air velocity, air temperature, soil grain size and different contaminant properties. This study showed that sparging air at ambient temperature through the contaminated soil can remove NAPLs, however, employing hot air sparging can provide higher contaminant removal efficiency, by about 9%. An empirical correlation for the volatilization mass transfer coefficient was developed from the experimental results. The dimensionless numbers used were Sherwood number (Sh), Peclet number (Pe), Schmidt number (Sc) and several physical-chemical properties of VOCs and porous media. Finally, the estimated volatilization mass transfer coefficient was used for calculation of the influence of heated sparging air on the spreading of the NAPL plume through the contaminated soil.

  1. Simulating the fate and transport of TCE from groundwater to indoor air.

    PubMed

    Yu, Soonyoung; Unger, Andre J A; Parker, Beth

    2009-07-21

    This work provides an exploratory analysis on the relative importance of various factors controlling the fate and transport of volatile organic contaminants (in this case, TCE) from a DNAPL source zone located below the water table and into the indoor air. The analysis is conducted using the multi-phase compositional model CompFlow Bio, with the base scenario problem geometry reminiscent of a field experiment conducted by Rivett [Rivett, M.O., (1995), Soil-gas signatures from volatile chlorinated solvents: Borden field experiments. Groundwater, 33(1), 84-98.] at the Borden aquifer where groundwater was observed to transport a contaminant plume a substantial distance without vertical mass transport of the contaminant across the capillary fringe and into the vadose zone. Results for the base scenario model indicate that the structure of the permeability field was largely responsible for deflecting the groundwater plume upward towards the capillary fringe, permitting aqueous phase diffusion to transport the TCE into the vadose zone. Alternative permeability realizations, generated as part of a Monte Carlo simulation process, at times deflected the groundwater plume downwards causing the extended thickness of the saturated zone to insulate the vadose zone from exposure to the TCE by upward diffusive transport. Comparison of attenuation coefficients calculated using the CompFlow Bio and Johnson and Ettinger [Johnson, P.C. and Ettinger, R.A., (1991), Heuristic model for predicting the intrusion rate of contaminant vapors into buildings. Environmental Science and Technology, 25, 1445-1452.] heuristic model exhibited fortuitous agreement for the base scenario problem geometry, with this agreement diverging for the alternative permeability realizations as well as when parameters such as the foundation slab fracture aperture, the indoor air pressure drop, the capillary fringe thickness, and the infiltration rate were varied over typical ranges. PMID:19525028

  2. Assessment of heavy metals in soils and groundwater in an urban watershed of Yaoundé (Cameroon-West Africa).

    PubMed

    Defo, Célestin; Yerima, Bernard Palmer Kfuban; Noumsi, Ives Magloire Kengne; Bemmo, Nestor

    2015-03-01

    The aim of this study was to investigate the heavy metals concentrations in soils and groundwater within the Ntem watershed in Yaoundé, to prevent the risk on the public health. Soils investigated were sampled in five (05) representative profiles at the surface and the bottom of the unsaturated zone of each profile. Soil samples were air-dried and ground to pass through a 2-mm sieve, and different soil extracts were prepared for chemical analysis (organic matter, cation exchange capacity and pH). By soil digestion method with diacid, total Pb, Cd, Cr and Ni were extracted and determined by atomic absorption spectrophotometry (AAS). Representative groundwater samples were also collected directly from some soil profiles and analysed using AAS instrument after filtration. Average metals concentrations in groundwater were higher than those of the World Health Organisation (WHO) norms. Besides, the geo-accumulation indices (Igeo) were ranged between zero and one (0 < Igeo < 1) for Pb (0.13-0.19), Cr (0.13-0.16) and Ni (0.09-0.11), indicating that the soils are contaminated by these metals, except Cd (Igeo < 0) in the whole watershed. Gleysols (Mollic (Igeo = 0.18) and Plenthic (Igeo = 0.16)) were found more contaminated than Ferralsols (Igeo = 0.15). Regardless of the sampling stations, soils were typified polluted by metals (pollution index (PI) > 1), except Cd (PI < 1). The integrated pollution index (IPI) values were ranged in descending order for soil pollution level as follows: Mollic Gleysols (3.47-4.94) > Plenthic Gleysol (1.89) > Xanthic Ferralsol (1.79) > Rhodic Ferralsol (1.69). The soils and groundwater pollution observed may be a severe threat for the public health in this watershed. PMID:25648762

  3. Assessment of heavy metals in soils and groundwater in an urban watershed of Yaoundé (Cameroon-West Africa).

    PubMed

    Defo, Célestin; Yerima, Bernard Palmer Kfuban; Noumsi, Ives Magloire Kengne; Bemmo, Nestor

    2015-03-01

    The aim of this study was to investigate the heavy metals concentrations in soils and groundwater within the Ntem watershed in Yaoundé, to prevent the risk on the public health. Soils investigated were sampled in five (05) representative profiles at the surface and the bottom of the unsaturated zone of each profile. Soil samples were air-dried and ground to pass through a 2-mm sieve, and different soil extracts were prepared for chemical analysis (organic matter, cation exchange capacity and pH). By soil digestion method with diacid, total Pb, Cd, Cr and Ni were extracted and determined by atomic absorption spectrophotometry (AAS). Representative groundwater samples were also collected directly from some soil profiles and analysed using AAS instrument after filtration. Average metals concentrations in groundwater were higher than those of the World Health Organisation (WHO) norms. Besides, the geo-accumulation indices (Igeo) were ranged between zero and one (0 < Igeo < 1) for Pb (0.13-0.19), Cr (0.13-0.16) and Ni (0.09-0.11), indicating that the soils are contaminated by these metals, except Cd (Igeo < 0) in the whole watershed. Gleysols (Mollic (Igeo = 0.18) and Plenthic (Igeo = 0.16)) were found more contaminated than Ferralsols (Igeo = 0.15). Regardless of the sampling stations, soils were typified polluted by metals (pollution index (PI) > 1), except Cd (PI < 1). The integrated pollution index (IPI) values were ranged in descending order for soil pollution level as follows: Mollic Gleysols (3.47-4.94) > Plenthic Gleysol (1.89) > Xanthic Ferralsol (1.79) > Rhodic Ferralsol (1.69). The soils and groundwater pollution observed may be a severe threat for the public health in this watershed.

  4. In-situ remediation system for groundwater and soils

    DOEpatents

    Corey, J.C.; Kaback, D.S.; Looney, B.B.

    1993-11-23

    A method and system are presented for in-situ remediation of contaminated groundwater and soil where the contaminants, such as toxic metals, are carried in a subsurface plume. The method comprises selection and injection into the soil of a fluid that will cause the contaminants to form stable, non-toxic compounds either directly by combining with the contaminants or indirectly by creating conditions in the soil or changing the conditions of the soil so that the formation of stable, non-toxic compounds between the contaminants and existing substances in the soil are more favorable. In the case of non-toxic metal contaminants, sulfides or sulfates are injected so that metal sulfides or sulfates are formed. Alternatively, an inert gas may be injected to stimulate microorganisms in the soil to produce sulfides which, in turn, react with the metal contaminants. Preferably, two wells are used, one to inject the fluid and one to extract the unused portion of the fluid. The two wells work in combination to create a flow of the fluid across the plume to achieve better, more rapid mixing of the fluid and the contaminants. 4 figures.

  5. In-situ remediation system for groundwater and soils

    DOEpatents

    Corey, John C.; Kaback, Dawn S.; Looney, Brian B.

    1993-01-01

    A method and system for in-situ remediation of contaminated groundwater and soil where the contaminants, such as toxic metals, are carried in a subsurface plume. The method comprises selection and injection into the soil of a fluid that will cause the contaminants to form stable, non-toxic compounds either directly by combining with the contaminants or indirectly by creating conditions in the soil or changing the conditions of the soil so that the formation of stable, non-toxic compounds between the contaminants and existing substances in the soil are more favorable. In the case of non-toxic metal contaminants, sulfides or sulfates are injected so that metal sulfides or sulfates are formed. Alternatively, an inert gas may be injected to stimulate microorganisms in the soil to produce sulfides which, in turn, react with the metal contaminants. Preferably, two wells are used, one to inject the fluid and one to extract the unused portion of the fluid. The two wells work in combination to create a flow of the fluid across the plume to achieve better, more rapid mixing of the fluid and the contaminants.

  6. Chemical-Specific Representation of Air-Soil Exchange and Soil Penetration in Regional Multimedia Models

    SciTech Connect

    McKone, T.E.; Bennett, D.H.

    2002-08-01

    In multimedia mass-balance models, the soil compartment is an important sink as well as a conduit for transfers to vegetation and shallow groundwater. Here a novel approach for constructing soil transport algorithms for multimedia fate models is developed and evaluated. The resulting algorithms account for diffusion in gas and liquid components; advection in gas, liquid, or solid phases; and multiple transformation processes. They also provide an explicit quantification of the characteristic soil penetration depth. We construct a compartment model using three and four soil layers to replicate with high reliability the flux and mass distribution obtained from the exact analytical solution describing the transient dispersion, advection, and transformation of chemicals in soil with fixed properties and boundary conditions. Unlike the analytical solution, which requires fixed boundary conditions, the soil compartment algorithms can be dynamically linked to other compartments (air, vegetation, ground water, surface water) in multimedia fate models. We demonstrate and evaluate the performance of the algorithms in a model with applications to benzene, benzo(a)pyrene, MTBE, TCDD, and tritium.

  7. Thermal Removal of Tritium from Concrete and Soil to Reduce Groundwater Impacts - 13197

    SciTech Connect

    Jackson, Dennis G.; Blount, Gerald C.; Wells, Leslie H.; Cardoso, Joao E.; Kmetz, Thomas F.; Reed, Misty L.

    2013-07-01

    Legacy heavy-water moderator operations at the Savannah River Site (SRS) have resulted in the contamination of equipment pads, building slabs, and surrounding soil with tritium. At the time of discovery the tritium had impacted the shallow (< 3-m) groundwater at the facility. While tritium was present in the groundwater, characterization efforts determined that a significant source remained in a concrete slab at the surface and within the associated vadose zone soils. To prevent continued long-term impacts to the shallow groundwater a CERCLA non-time critical removal action for these source materials was conducted to reduce the leaching of tritium from the vadose zone soils and concrete slabs. In order to minimize transportation and disposal costs, an on-site thermal treatment process was designed, tested, and implemented. The on-site treatment consisted of thermal detritiation of the concrete rubble and soil. During this process concrete rubble was heated to a temperature of 815 deg. C (1,500 deg. F) resulting in the dehydration and removal of water bound tritium. During heating, tritium contaminated soil was used to provide thermal insulation during which it's temperature exceeded 100 deg. C (212 deg. F), causing drying and removal of tritium. The thermal treatment process volatiles the water bound tritium and releases it to the atmosphere. The released tritium was considered insignificant based upon Clean Air Act Compliance Package (CAP88) analysis and did not exceed exposure thresholds. A treatability study evaluated the effectiveness of this thermal configuration and viability as a decontamination method for tritium in concrete and soil materials. Post treatment sampling confirmed the effectiveness at reducing tritium to acceptable waste site specific levels. With American Recovery and Reinvestment Act (ARRA) funding three additional treatment cells were assembled utilizing commercial heating equipment and common construction materials. This provided a total

  8. Thermal Removal Of Tritium From Concrete And Soil To Reduce Groundwater Impacts

    SciTech Connect

    Jackson, Dennis G.; Blount, Gerald C.; Wells, Leslie H.; Cardoso-Neto, Joao E.; Kmetz, Thomas F.; Reed, Misty L.

    2012-12-04

    Legacy heavy-water moderator operations at the Savannah River Site (SRS) have resulted in the contamination of equipment pads, building slabs, and surrounding soil with tritium. At the time of discovery the tritium had impacted the shallow (< 3-m) groundwater at the facility. While tritium was present in the groundwater, characterization efforts determined that a significant source remained in a concrete slab at the surface and within the associated vadose zone soils. To prevent continued long-term impacts to the shallow groundwater a CERCLA non-time critical removal action for these source materials was conducted to reduce the leaching of tritium from the vadose zone soils and concrete slabs. In order to minimize transportation and disposal costs, an on-site thermal treatment process was designed, tested, and implemented. The on-site treatment consisted of thermal detritiation of the concrete rubble and soil. During this process concrete rubble was heated to a temperature of 815 deg C (1,500 deg F) resulting in the dehydration and removal of water bound tritium. During heating, tritium contaminated soil was used to provide thermal insulation during which it's temperature exceeded 100 deg C (212 deg F), causing drying and removal of tritium. The thermal treatment process volatiles the water bound tritium and releases it to the atmosphere. The released tritium was considered insignificant based upon Clean Air Act Compliance Package (CAP88) analysis and did not exceed exposure thresholds. A treatability study evaluated the effectiveness of this thermal configuration and viability as a decontamination method for tritium in concrete and soil materials. Post treatment sampling confirmed the effectiveness at reducing tritium to acceptable waste site specific levels. With American Recovery and Reinvestment Act (ARRA) funding three additional treatment cells were assembled utilizing commercial heating equipment and common construction materials. This provided a total of

  9. Superfund explanation of significant difference for the record of decision (EPA Region 10): Harbor Island, Soil and Groundwater Operable Unit, Seattle, WA, July 26, 1994

    SciTech Connect

    1995-03-01

    One of the components of the selected remedy in the Record of Decision (ROD) for the Soil and Groundwater Unit of the Harbor Island Site (Site) was thermal desorption with condensate collection to treat petroleum contaminated soil. However, after further evaluation of the performance of this technology, it became apparent that it would not meet air emission standards for volatile organic compounds set by the Puget Sound Air Pollution Control Agency (PSAPCA).

  10. Can soil gas VOCs be related to groundwater plumes based on their isotope signature?

    PubMed

    Jeannottat, S; Hunkeler, D

    2013-01-01

    The isotope evolution of tetrachloroethene (PCE) during its transport from groundwater toward the soil surface was investigated using laboratory studies and numerical modeling. During air-water partitioning, carbon and chlorine isotope ratios evolved in opposite directions, with a normal isotope effect for chlorine (ε = -0.20‰) and an inverse effect for carbon (ε = +0.46‰). During the migration of PCE from groundwater to the unsaturated zone in a 2D laboratory system, small shifts of carbon and chlorine isotope ratios (+0.8‰) were observed across the capillary fringe. Numerical modeling showed that these shifts are due to isotope fractionation associated with air-water partitioning and gas-phase diffusion. Carbon and chlorine isotope profiles were constant throughout the unsaturated zone once a steady state was reached. However, depending on the thickness of the unsaturated zone and its lithology, depletion in heavy isotopes may occur with distance during the transient migration of contaminants. Additionally, variations of up to +1.5‰ were observed in the unsaturated zone for chlorine isotopes during water table fluctuations. However, at steady state, it is possible to link a groundwater plume to gas-phase contamination and/or to differentiate sources of contamination based on isotope ratios.

  11. Phase 1 remediation of jet fuel contaminated soil and groundwater at JFK International Airport using dual phase extraction and bioventing

    SciTech Connect

    Roth, R.; Bianco, P. Rizzo, M.; Pressly, N.; Frumer, B.

    1995-12-31

    Soil and groundwater contaminated with jet fuel at Terminal One of the JFK International Airport in New York have been remediated using dual phase extraction (DPE) and bioventing. Two areas were remediated using 51 DPE wells and 20 air sparging/air injection wells. The total area remediated by the DPE wells is estimated to be 4.8 acres. Groundwater was extracted to recover nonaqueous phase and aqueous phase jet fuel from the shallow aquifer and treated above ground by the following processes; oil/water separation, iron-oxidation, flocculation, sedimentation, filtration, air stripping and liquid-phase granular activated carbon (LPGAC) adsorption. The extracted vapors were treated by vapor-phase granular activated carbon (VPGAC) adsorption in one area, and catalytic oxidation and VPGAC adsorption in another area. After 6 months of remediation, approximately 5,490 lbs. of volatile organic compounds (VOCs) were removed by soil vapor extraction (SVE), 109,650 lbs. of petroleum hydrocarbons were removed from the extracted groundwater, and 60,550 lbs. of petroleum hydrocarbons were biologically oxidized by subsurface microorganisms. Of these three mechanisms, the rate of petroleum hydrocarbon removal was the highest for biological oxidation in one area and by groundwater extraction in another area.

  12. Effect of groundwater flow on remediation of dissolved-phase VOC contamination using air sparging.

    PubMed

    Reddy, K R; Adams, J A

    2000-02-25

    This paper presents two-dimensional laboratory experiments performed to study how groundwater flow may affect the injected air zone of influence and remedial performance, and how injected air may alter subsurface groundwater flow and contaminant migration during in situ air sparging. Tests were performed by subjecting uniform sand profiles contaminated with dissolved-phase benzene to a hydraulic gradient and two different air flow rates. The results of the tests were compared to a test subjected to a similar air flow rate but a static groundwater condition. The test results revealed that the size and shape of the zone of influence were negligibly affected by groundwater flow, and as a result, similar rates of contaminant removal were realized within the zone of influence with and without groundwater flow. The air flow, however, reduced the hydraulic conductivity within the zone of influence, reducing groundwater flow and subsequent downgradient contaminant migration. The use of a higher air flow rate further reduced the hydraulic conductivity and decreased groundwater flow and contaminant migration. Overall, this study demonstrated that air sparging may be effectively implemented to intercept and treat a migrating contaminant plume.

  13. Phytoremediation of organic contaminants in soil and groundwater.

    PubMed

    Reichenauer, Thomas G; Germida, James J

    2008-01-01

    Phytoremediation is an emerging technology for the clean-up of sites contaminated with hazardous chemicals. The term phytoremediation refers to a number of technologies that use photoautotrophic vascular plants for the remediation of sites contaminated with inorganic and organic contaminants. Phytoremediation of organic contaminants can be organized by considering 1) the green liver concept, which elucidates the metabolism of contaminants in planta versus that of contaminants ex planta (e.g. rhizosphere), 2) processes that lead to complete degradation (mineralization) of contaminants as opposed to those that only lead to partial degradation or transformation, and 3) active plant uptake versus passive processes (e.g. sorption). Understanding of these processes needs an interdisciplinary approach involving chemists, biologists, soil scientists, and environmentalists. This Review presents the basic concepts of phytoremediation of organic contaminants in soil and groundwater using selected contaminants as examples.

  14. STANDARDS CONTROLLING AIR EMISSIONS FOR THE SOIL DESICCATION PILOT TEST

    SciTech Connect

    BENECKE MW

    2010-09-08

    This air emissions document supports implementation of the Treatability Test Plan for Soil Desiccation as outlined in the Deep Vadose Zone Treatability Test Plan for the Hanford Central Plateau (DOE/RL-2007-56). Treatability testing supports evaluation of remedial technologies for technetium-99 (Tc-99) contamination in the vadose zone at sites such as the BC Cribs and Trenches. Soil desiccation has been selected as the first technology for testing because it has been recommended as a promising technology in previous Hanford Site technology evaluations and because testing of soil desiccation will provide useful information to enhance evaluation of other technologies, in particular gas-phase remediation technologies. A soil desiccation pilot test (SDPT) will evaluate the desiccation process (e.g., how the targeted interval is dried) and the long-term performance for mitigation of contaminant transport. The SDPT will dry out a moist zone contaminated by Tc-99 and nitrate that has been detected at Well 299-E13-62 (Borehole C5923). This air emissions document applies to the activities to be completed to conduct the SDPT in the 200-BC-1 operable unit located in the 200 East Area of the Hanford Site. Well 299-E13-62 is planned to be used as an injection well. This well is located between and approximately equidistant from cribs 216-B-16, 216-B-17, 216-B-18. and 216-B-19. Nitrogen gas will be pumped at approximately 300 ft{sup 3}/min into the 299-EI3-62 injection well, located approximately 12 m (39 ft) away from extraction well 299-EI3-65. The soil gas extraction rate will be approximately 150 ft{sup 3}/min. The SDPT will be conducted continuously over a period of approximately six months. The purpose of the test is to evaluate soil desiccation as a potential remedy for protecting groundwater. A conceptual depiction is provided in Figure 1. The soil desiccation process will physically dry, or evaporate, some of the water from the moist zone of interest. As such, it is

  15. Persistence of perfluoroalkyl acid precursors in AFFF-impacted groundwater and soil.

    PubMed

    Houtz, Erika F; Higgins, Christopher P; Field, Jennifer A; Sedlak, David L

    2013-08-01

    Several classes of polyfluorinated chemicals that are potential precursors to the perfluorinated carboxylates and sulfonates are present in aqueous film-forming foams (AFFF). To assess the persistence of these AFFF-derived precursors, groundwater, soil, and aquifer solids were obtained in 2011 from an unlined firefighter training area at a U.S. Air Force Base where AFFF was regularly used between 1970 and 1990. To measure the total concentration of perfluorinated carboxylate and sulfonate precursors in archived AFFF formulations and AFFF-impacted environmental samples, a previously developed assay that uses hydroxyl radical to oxidize precursors to perfluorinated carboxylates was adapted for these media. This assay was employed along with direct measurement of 22 precursors found in AFFF and a suite of other poly- and perfluoroalkyl substances (PFASs). On a molar basis, precursors accounted for 41-100% of the total concentration of PFASs in archived AFFF formulations. In the training area, precursors measured by the oxidation assay accounted for an average of 23% and 28% of total PFASs (i.e., precursors and perfluorinated carboxylates and sulfonates) in groundwater and solids samples, respectively. One precursor in AFFF, perfluorohexane sulfonamide amine, was observed on several highly contaminated soil and aquifer solids samples, but no other precursors present in AFFF formulations were detected in any samples at this field site. Suspected intermediate transformation products of precursors in AFFF that were directly measured accounted for approximately half of the total precursor concentration in samples from the training site. The fraction of PFASs consisting of perfluorinated carboxylates and sulfonates was greater in groundwater and solid samples than in any archived AFFF formulations, suggesting that much of the mass of precursors released at the site was converted to perfluorinated carboxylates and sulfonates. The precursors that have persisted at this site

  16. Field-scale relationships among soil properties and shallow groundwater quality.

    PubMed

    Derby, Nathan E; Korom, Scott F; Casey, Francis X M

    2013-01-01

    It is important to understand the link between land surface/soil properties and shallow groundwater quality. To that end, soil properties and near-water-table groundwater chemistry of a shallow, unconfined aquifer were measured on a 100-m grid on a 64-ha irrigated field in southeastern North Dakota. Soil properties and hydrochemistry were compared via multivariate analysis that included product-moment correlations and factor analysis/principal component analysis. Topographic low areas where the water table was in close proximity to the soil surface generally had higher apparent electrical conductivity (ECa ) and higher percent silt and clay than higher positions on the landscape. The majority of the groundwater was characterized by Ca- and Mg-HCO3 type water and was associated with topographic high areas with lower ECa and net groundwater recharge. Small topographic depressions were areas of higher ECa (net groundwater discharge) where salts that precipitated via evapotranspiration and evaporative discharge dissolved and leached to the groundwater during short-term depression-focused recharge events. At this site, groundwater quality and soil ECa were related to surface topography. High-resolution topography and EC(a) measurements are necessary to characterize the land surface/soil properties and surficial groundwater quality at the field-scale and to delineate areas where the shallow groundwater is most susceptible to contamination.

  17. Excess air formation as a mechanism for delivering oxygen to groundwater

    NASA Astrophysics Data System (ADS)

    Mächler, L.; Peter, S.; Brennwald, M. S.; Kipfer, R.

    2013-10-01

    The temporal dynamics and spatial distribution of the concentrations of dissolved gases (He, Ar, Kr, N2, O2, and CO2) in an infiltrating groundwater system fed by the peri-alpine river Thur (Switzerland) were analyzed before, during and after a single, well-defined flood event. The analysis was based on measurements taken in five different groundwater observation wells that were located approximately 10 m apart and tapped the same groundwater body, but were situated in three different riparian zones. The input of O2 into the groundwater as a result of the formation of excess air was found to be of the same order of magnitude as that resulting from the advection of river water, although the amount of excess air formed and the amount of O2 delivered varied significantly among the riparian zones. The results suggest that the input of O2 into groundwater as a result of excess air formation is controlled not only by the hydraulic conditions prevailing in the river and the groundwater, but also by the thickness of the confining bed at the top of the aquifer. The sandy gravel aquifer itself is too coarse to trap a significant amount of air during the water level rise. The clay layer confining the aquifer, however, acts as a barrier hindering the escape of air from the subsoil to the surface, and hence is likely to be a key factor controlling the trapping and dissolution of air in groundwater.

  18. Simulating tracer transport in variably saturated soils and shallow groundwater

    NASA Astrophysics Data System (ADS)

    Pan, F.; Yakirevich, A.; Guber, A.; Pachepsky, Y. A.; Gish, T. J.; Nicholson, T. J.; Cady, R.

    2009-12-01

    The objective of this study was to develop a realistic model to simulate the complex processes of flow and tracer transport in variably saturated soils and to compare simulation results with the detailed monitoring observations. The USDA-ARS OPE3 field site was selected for the case study due to availability of the extensive database on geophysical, biophysical, remote sensing, soil water and groundwater monitoring accumulated in past 10 years. High soil spatial heterogeneity and shallow groundwater were encountered at the site. A pulse of KCL solution was applied to the irrigation plot with an area of 13x14m, and then the plot was irrigated twice a day for three months using the tap water. The chloride concentration was measured at three sampling depths of 12 observation wells at 7 m and 14 m distances from the irrigation plot. Two three-dimensional flow and transport models, HYDRUS-3D and TOUGH2 codes, were applied in this study to simulate flow and chloride transport for the tracer experiment. Respectively, these models represent two conceptual approaches for flow and transport: (a) transport through all of the domain (b) preferential transport via a network of well-connected pathways (fractures) that comprise only part of the bulk soil porosity (matrix) at the field scale, assuming mass exchange between fracture and matrix continua. The atmospheric boundary condition was applied at surface of the model domain and no flux boundary was set at the bottom. The spatially variable and temporally constant pressure heads were specified along the lateral boundaries. The trial-and-error calibration based on zonation of the flow and transport domain was reasonably successful. The maximum concentration levels and the 50% concentration arrival times were described satisfactory. However, with HYDRUS3D we could not accurately reproduce the shape of the breakthrough curves, unlike TOUGH2 that better simulated the front and tailing part of observed breakthrough curves. The

  19. Simulation of large-scale soil water systems using groundwater data and satellite based soil moisture

    NASA Astrophysics Data System (ADS)

    Kreye, Phillip; Meon, Günter

    2016-04-01

    Complex concepts for the physically correct depiction of dominant processes in the hydrosphere are increasingly at the forefront of hydrological modelling. Many scientific issues in hydrological modelling demand for additional system variables besides a simulation of runoff only, such as groundwater recharge or soil moisture conditions. Models that include soil water simulations are either very simplified or require a high number of parameters. Against this backdrop there is a heightened demand of observations to be used to calibrate the model. A reasonable integration of groundwater data or remote sensing data in calibration procedures as well as the identifiability of physically plausible sets of parameters is subject to research in the field of hydrology. Since this data is often combined with conceptual models, the given interfaces are not suitable for such demands. Furthermore, the application of automated optimisation procedures is generally associated with conceptual models, whose (fast) computing times allow many iterations of the optimisation in an acceptable time frame. One of the main aims of this study is to reduce the discrepancy between scientific and practical applications in the field of hydrological modelling. Therefore, the soil model DYVESOM (DYnamic VEgetation SOil Model) was developed as one of the primary components of the hydrological modelling system PANTA RHEI. DYVESOMs structure provides the required interfaces for the calibrations made at runoff, satellite based soil moisture and groundwater level. The model considers spatial and temporal differentiated feedback of the development of the vegetation on the soil system. In addition, small scale heterogeneities of soil properties (subgrid-variability) are parameterized by variation of van Genuchten parameters depending on distribution functions. Different sets of parameters are operated simultaneously while interacting with each other. The developed soil model is innovative regarding concept

  20. PHYTOREMEDIATION OF GROUNDWATER AT AIR FORCE PLANT 4, CARSWELL, TEXAS - INNOVATIVE TECHNOLOGY EVALUATION REPORT

    EPA Science Inventory

    Over 600 Cottonwood trees were planted over a shallow groundwater plume in an attempt to detoxify the trichloroethylene (TCE) in a groundwater plume at a former Air Force facility. Two planting techniques were used: rooted stock about two years old, and 18 inch cuttings were inst...

  1. Impacts of Shallow Groundwater and Soil Texture on Agricultural Drought Resistance

    NASA Astrophysics Data System (ADS)

    Zipper, S. C.; Soylu, M. E.; Booth, E.; Steven, L. I.

    2015-12-01

    Meeting increasing global food demands while fostering environmental sustainability requires a detailed understanding of the drivers of yield sensitivity within agroecosystems. In this study, we untangle the roles of soil texture and shallow groundwater as simultaneous drivers of corn yield resistance to excessively wet and dry growing seasons. Specifically, we ask (1) does the presence of groundwater in or near the root zone increase/decrease yield?; and (2) how does yield response to water table depth interact with variability in soil texture and growing season weather conditions? We combine a multi-year field study at a commercial corn field in south-central Wisconsin with ecohydrological modeling using AgroIBIS-VSF to assess the yield response to a broad spectrum of groundwater, soil, and weather conditions. We find that shallow groundwater (<1 m) increases yield sensitivity to overly wet growing season conditions, but acts as a stable reservoir of water to increase drought resistance by providing a groundwater yield subsidy during dry years. Modeling results indicate that coarser soils receive a groundwater yield subsidy at shallower water table depths than finer-grained soils, and that the magnitude of the groundwater yield subsidy tends to be larger. We also find that crops growing on soils with different textures experience a comparable response to changes in growing season precipitation and evapotranspiration demands. Overall, we find that the benefits of shallow groundwater (drought resistance) outweigh the negatives (waterlogging and yield loss) at our study site.

  2. Relative air permeability as function of saturation in soil venting

    SciTech Connect

    Stylianou, C.; DeVantier, B.A.

    1995-04-01

    Traditionally, soil remediation involved soil flushing, or excavation followed by landfilling or treatment. In recent years, recognizing the major environmental problem of soil contamination by VOCs, soil vapor extraction (SVE, also known as soil venting) has been applied as a form of in situ remediation. A key parameter in modeling soil-venting systems is relative air permeability, determined as a function of liquid saturation. The focus of the present study was to characterize the relationship of the relative air permeability as a function of air saturation in soil-venting systems. A new laboratory apparatus was used to simulate the soil venting and measure the air permeability of soil samples. Sand samples wetted with mixtures of water and gasoline at different ratios were used. It was revealed that the prediction of relative air permeability for moist noncohesive soil can be made in terms of intrinsic permeability and air-filled porosity alone, and not the type of liquid present in the pores. Comparisons of measured data with existing relations for relative air permeability as a function of total liquid saturation were made to determine the most accurate and practical forms for engineering applications. For the sand sample used, the evaluation revealed that compared to the existing relations, a derived second-order polynomial expression provides a good estimate of relative air permeability and does not require estimation of soil-water-retention curve parameters.

  3. Fiscal Year 2010 Program of the U.S. DOE Office of Groundwater and Soil Remediation

    SciTech Connect

    Chamberlain, G. M.; Skubal, Karen L.; Wellman, Dawn M.

    2011-03-07

    The mission of the Office of Groundwater and Soil Remediation (EM-32) is to perform assessments, establish technical criteria and promote cross-site integration. The Office provides guidance for the development and implementation of plans for remediation of groundwater and is responsible for development of technologies needed to reduce risk from groundwater contamination. It is also responsible for providing technical direction and/or assistance to sites in resolving difficult technical groundwater and soil remediation problems. This paper discusses the activities funded by EM-32 for FY-2010.

  4. Scientific Opportunity to Reduce Risk in Groundwater and Soil Remediation

    SciTech Connect

    Pierce, Eric M.; Freshley, Mark D.; Hubbard, Susan S.; Looney, Brian B.; Zachara, John M.; Liang, Liyuan; Lesmes, D.; Chamberlain, G. M.; Skubal, Karen L.; Adams, V.; Denham, Miles E.; Wellman, Dawn M.

    2009-08-25

    In this report, we start by examining previous efforts at linking science and DOE EM research with cleanup activities. Many of these efforts were initiated by creating science and technology roadmaps. A recurring feature of successfully implementing these roadmaps into EM applied research efforts and successful cleanup is the focus on integration. Such integration takes many forms, ranging from combining information generated by various scientific disciplines, to providing technical expertise to facilitate successful application of novel technology, to bringing the resources and creativity of many to address the common goal of moving EM cleanup forward. Successful projects identify and focus research efforts on addressing the problems and challenges that are causing “failure” in actual cleanup activities. In this way, basic and applied science resources are used strategically to address the particular unknowns that are barriers to cleanup. The brief descriptions of the Office of Science basic (Environmental Remediation Science Program [ERSP]) and EM’s applied (Groundwater and Soil Remediation Program) research programs in subsurface science provide context to the five “crosscutting” themes that have been developed in this strategic planning effort. To address these challenges and opportunities, a tiered systematic approach is proposed that leverages basic science investments with new applied research investments from the DOE Office of Engineering and Technology within the framework of the identified basic science and applied research crosscutting themes. These themes are evident in the initial portfolio of initiatives in the EM groundwater and soil cleanup multi-year program plan. As stated in a companion document for tank waste processing (Bredt et al. 2008), in addition to achieving its mission, DOE EM is experiencing a fundamental shift in philosophy from driving to closure to enabling the long-term needs of DOE and the nation.

  5. Using radon-222 as indicator for the evaluation of the efficiency of groundwater remediation by in situ air sparging.

    PubMed

    Schubert, Michael; Schmidt, Axel; Müller, Kai; Weiss, Holger

    2011-02-01

    A common approach for remediation of groundwater contamination with volatile organic compounds (VOCs) is contaminant stripping by means of in situ air sparging (IAS). For VOC stripping, pressurized air is injected into the contaminated groundwater volume, followed by the extraction of the contaminant-loaded exhaust gas from the vadose soil zone and its immediate on-site treatment. Progress assessment of such remediation measure necessitates information (i) on the spatial range of the IAS influence and (ii) on temporal variations of the IAS efficiency. In the present study it was shown that the naturally occurring noble gas radon can be used as suitable environmental tracer for achieving the related spatial and temporal information. Due to the distinct water/air partitioning behaviour of radon and due to its straightforward on-site detectability, the radon distribution pattern in the groundwater can be used as appropriate measure for assessing the progression of an IAS measure as a function of space and time. The presented paper discusses both the theoretical background of the approach and the results of an IAS treatment accomplished at a VOC contaminated site lasting six months, during which radon was applied as efficiency indicator.

  6. Effects of changing channel morphology on vegetation, groundwater, and soil moisture regimes in groundwater dependent ecosystems

    NASA Astrophysics Data System (ADS)

    Loheide, S. P.; Booth, E. G.

    2008-12-01

    Channel incision and excessive floodplain sedimentation are major causes of riparian degradation across the country. Though the causes and consequences of these processes vary significantly, the resulting morphology in both cases is steep streambanks and a stream that is less connected with the floodplain. A case study from semi-arid, wet meadows with snow-melt driven hydrology in the Sierra Nevada of CA will be compared with one from a riparian wet prairie in the humid environment of the Driftless Area of southern Wisconsin. In the mountain meadows, 80 years of logging and overgrazing led to more flashy runoff and downcutting of the stream. This led to drainage of groundwater from the meadow and a shift in vegetation composition from sedges and rushes to dryland grasses and sagebrush in this groundwater dependent ecosystem. In the Driftless Area of WI, the introduction of agricultural practices by European settlers in the 1830s resulted in severe erosion from the cropped areas in the uplands. This sediment was transported to the stream valleys where it was deposited on the floodplain, raising this surface relative to the streambed. As a result, the water table is at a greater depth from this elevated land surface. In this ecosystem, the vegetation has shifted from wet prairie and sedge meadow communities to grasses and lowland forests dominated by box elder trees. The geomorphic result at both sites was a channel bounded by tall banks with reduced hydrologic connectivity with the floodplain. In both cases, the slope of the water table towards the stream is greater than the topographic slope across the riparian zone and the greatest depth to the water table is found adjacent to the channel. Transects exhibit a decreasing trend in soil moisture with increasing variability toward the channel. Remotely sensed imagery shows trends of drier vegetation communities adjacent to channels and wetter vegetation communities toward the margin of the riparian zones. Coupled

  7. Contamination valuation of soil and groundwater source at anaerobic municipal solid waste landfill site.

    PubMed

    Aziz, Shuokr Qarani; Maulood, Yousif Ismael

    2015-12-01

    The present work aimed to determine the risks that formed landfill leachate from anaerobic Erbil Landfill Site (ELS) poses on groundwater source and to observe the effects of disposed municipal solid waste (MSW) on soil properties. The study further aims to fill the gap in studies on the effects of disposed MSW and produced leachate on the groundwater characteristics and soil quality at ELS, Iraq. Soil, leachate, and groundwater samples were collected from ELS for use as samples in this study. Unpolluted groundwater samples were collected from an area outside of the landfill. Field and laboratory experiments for the soil samples were conducted. Chemical analyses for the soil samples such as organic matter, total salts, and SO4 (=) were also performed. Raw leachate and groundwater samples were analyzed using physical and chemical experiments. The yields for sorptivity, steady-state infiltration rate, and hydraulic conductivity of the soil samples were 0.0006 m/√s, 0.00004 m/s, and 2.17 × 10(-5) m/s, respectively. The soil at ELS was found to be light brown clayey gravel with sand and light brown gravely lean clay layers with low permeability. Unprocessed leachate analysis identified the leachate as stabilized. Findings showed that the soil and groundwater at the anaerobic ELS were contaminated.

  8. Contamination valuation of soil and groundwater source at anaerobic municipal solid waste landfill site.

    PubMed

    Aziz, Shuokr Qarani; Maulood, Yousif Ismael

    2015-12-01

    The present work aimed to determine the risks that formed landfill leachate from anaerobic Erbil Landfill Site (ELS) poses on groundwater source and to observe the effects of disposed municipal solid waste (MSW) on soil properties. The study further aims to fill the gap in studies on the effects of disposed MSW and produced leachate on the groundwater characteristics and soil quality at ELS, Iraq. Soil, leachate, and groundwater samples were collected from ELS for use as samples in this study. Unpolluted groundwater samples were collected from an area outside of the landfill. Field and laboratory experiments for the soil samples were conducted. Chemical analyses for the soil samples such as organic matter, total salts, and SO4 (=) were also performed. Raw leachate and groundwater samples were analyzed using physical and chemical experiments. The yields for sorptivity, steady-state infiltration rate, and hydraulic conductivity of the soil samples were 0.0006 m/√s, 0.00004 m/s, and 2.17 × 10(-5) m/s, respectively. The soil at ELS was found to be light brown clayey gravel with sand and light brown gravely lean clay layers with low permeability. Unprocessed leachate analysis identified the leachate as stabilized. Findings showed that the soil and groundwater at the anaerobic ELS were contaminated. PMID:26577215

  9. Precipitation and Air Temperature Impact on Seasonal Variations of Groundwater Levels

    NASA Astrophysics Data System (ADS)

    Vitola, Ilva; Vircavs, Valdis; Abramenko, Kaspars; Lauva, Didzis; Veinbergs, Arturs

    2012-12-01

    The aim of this study is to clarify seasonal effects of precipitation and temperature on groundwater level changes in monitoring stations of the Latvia University of Agriculture - Mellupīte, Bērze and Auce. Groundwater regime and level fluctuations depend on climatic conditions such as precipitation intensity, evapotranspiration, surface runoff and drainage, as well as other hydrological factors. The relationship between precipitation, air temperature and groundwater level fluctuations could also lead and give different perspective of possible changes in groundwater quality. Using mathematical statistics and graphic-analytic methods it is concluded that autumn and winter precipitation has the dominant impact on groundwater level fluctuations, whereas spring and summer season fluctuations are more dependent on the air temperature.

  10. 40 CFR 280.65 - Investigations for soil and ground-water cleanup.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Investigations for soil and ground... Containing Petroleum or Hazardous Substances § 280.65 Investigations for soil and ground-water cleanup. (a) In order to determine the full extent and location of soils contaminated by the release and...

  11. 40 CFR 280.65 - Investigations for soil and ground-water cleanup.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Investigations for soil and ground... Containing Petroleum or Hazardous Substances § 280.65 Investigations for soil and ground-water cleanup. (a) In order to determine the full extent and location of soils contaminated by the release and...

  12. 40 CFR 280.65 - Investigations for soil and ground-water cleanup.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Investigations for soil and ground... Containing Petroleum or Hazardous Substances § 280.65 Investigations for soil and ground-water cleanup. (a) In order to determine the full extent and location of soils contaminated by the release and...

  13. 40 CFR 280.65 - Investigations for soil and ground-water cleanup.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Investigations for soil and ground... Containing Petroleum or Hazardous Substances § 280.65 Investigations for soil and ground-water cleanup. (a) In order to determine the full extent and location of soils contaminated by the release and...

  14. Phytoremediation of contaminated soils and groundwater: lessons from the field

    SciTech Connect

    Vangronsveld, J.; van der Lelie, D.; Herzig, R.; Weyens, N.; Boulet, J.; Adriaensen, K.; Ruttens, A.; Thewys, T.; Vassilev, A.; Meers, E.; Nehnevajova, E.; Mench, M.

    2009-11-01

    The use of plants and associated microorganisms to remove, contain, inactivate, or degrade harmful environmental contaminants (generally termed phytoremediation) and to revitalize contaminated sites is gaining more and more attention. In this review, prerequisites for a successful remediation will be discussed. The performance of phytoremediation as an environmental remediation technology indeed depends on several factors including the extent of soil contamination, the availability and accessibility of contaminants for rhizosphere microorganisms and uptake into roots (bioavailability), and the ability of the plant and its associated microorganisms to intercept, absorb, accumulate, and/or degrade the contaminants. The main aim is to provide an overview of existing field experience in Europe concerning the use of plants and their associated microorganisms whether or not combined with amendments for the revitalization or remediation of contaminated soils and undeep groundwater. Contaminations with trace elements (except radionuclides) and organics will be considered. Because remediation with transgenic organisms is largely untested in the field, this topic is not covered in this review. Brief attention will be paid to the economical aspects, use, and processing of the biomass. It is clear that in spite of a growing public and commercial interest and the success of several pilot studies and field scale applications more fundamental research still is needed to better exploit the metabolic diversity of the plants themselves, but also to better understand the complex interactions between contaminants, soil, plant roots, and microorganisms (bacteria and mycorrhiza) in the rhizosphere. Further, more data are still needed to quantify the underlying economics, as a support for public acceptance and last but not least to convince policy makers and stakeholders (who are not very familiar with such techniques).

  15. Heavy metal concentrations in groundwaters and soils of Thane Region of Maharashtra, India.

    PubMed

    Bhagure, Ganesh Ramdas; Mirgane, S R

    2011-02-01

    Thane district is one of the most industrialized districts in Maharashtra. The heavy industrialization and the increasing urbanization are responsible for the rapidly increasing stress on the water and soil environment of the area. Therefore, an attempt has been made through comprehensive study on the groundwater contamination and soil contamination due to heavy metals in Thane region of Maharashtra. The area undertaken for the study was Thane and its suburbans Kalwa, Divajunction, Dombivali, Kalyan, and Ulhasnagar. Industrialization and urbanization lead to generation of large volumes of wastewater from domestic, commercial, industrial, and other sources, which discharged in to natural water bodies like river and creek in this region. Groundwater samples and soil samples were collected from residential, commercial, agriculture, and industrial areas. Groundwater samples were analyzed for various water quality parameters. The analytical data shows very high concentration of total dissolved solids, total hardness, total alkalinity, chemical oxygen demand, chloride etc. Groundwater and soil samples were analyzed for ten heavy metals by inductively coupled plasma (ICPE-9000) atomic emission spectroscopy. The analytical data reveal that, very high concentration level of arsenic, cadmium, mercury, and nickel throughout the industrial area. The random dumping of hazardous waste in the industrial area could be the main cause of the groundwater and soil contamination spreading by rainwater and wind. In the residential areas the local dumping is expected to be the main source for heavy metals. A comparison of the results of groundwater with WHO guidelines show that most of the groundwater sampling station are heavily contaminated with organic matter and heavy metals. Groundwater samples are heavily contaminated by arsenic, cadmium, mercury, and nickel. Similarly, the results of heavy metals in soil compared with Swedish soil guideline values for polluted soil show that soil

  16. The Soils and Groundwater – EM-20 S&T Roadmap Quality Assurance Project Plan

    SciTech Connect

    Fix, N. J.

    2008-02-11

    The Soils and Groundwater – EM-20 Science and Technology Roadmap Project is a U.S. Department of Energy, Office of Environmental Management-funded initiative designed to develop new methods, strategies and technology for characterizing, modeling, remediating, and monitoring soils and groundwater contaminated with metals, radionuclides, and chlorinated organics. This Quality Assurance Project Plan provides the quality assurance requirements and processes that will be followed by EM-20 Roadmap Project staff.

  17. DEPARTMENT OF ENERGY SOIL AND GROUNDWATER SCIENCE AND TECHNOLOGY NEEDS, PLANS AND INITIATIVES

    SciTech Connect

    Aylward, B; V. ADAMS, V; G. M. CHAMBERLAIN, G; T. L. STEWART, T

    2007-12-12

    This paper presents the process used by the Department of Energy (DOE) Environmental Management (EM) Program to collect and prioritize DOE soil and groundwater site science and technology needs, develop and document strategic plans within the EM Engineering and Technology Roadmap, and establish specific program and project initiatives for inclusion in the EM Multi-Year Program Plan. The paper also presents brief summaries of the goals and objectives for the established soil and groundwater initiatives.

  18. China's soil and groundwater management challenges: Lessons from the UK's experience and opportunities for China.

    PubMed

    Coulon, Frédéric; Jones, Kevin; Li, Hong; Hu, Qing; Gao, Jingyang; Li, Fasheng; Chen, Mengfang; Zhu, Yong-Guan; Liu, Rongxia; Liu, Ming; Canning, Kate; Harries, Nicola; Bardos, Paul; Nathanail, Paul; Sweeney, Rob; Middleton, David; Charnley, Maggie; Randall, Jeremy; Richell, Martin; Howard, Trevor; Martin, Ian; Spooner, Simon; Weeks, Jason; Cave, Mark; Yu, Fang; Zhang, Fang; Jiang, Ying; Longhurst, Phil; Prpich, George; Bewley, Richard; Abra, Jonathan; Pollard, Simon

    2016-05-01

    There are a number of specific opportunities for UK and China to work together on contaminated land management issues as China lacks comprehensive and systematic planning for sustainable risk based land management, encompassing both contaminated soil and groundwater and recycling and reuse of soil. It also lacks comprehensive risk assessment systems, structures to support risk management decision making, processes for verification of remediation outcome, systems for record keeping and preservation and integration of contamination issues into land use planning, along with procedures for ensuring effective health and safety considerations during remediation projects, and effective evaluation of costs versus benefits and overall sustainability. A consequence of the absence of these overarching frameworks has been that remediation takes place on an ad hoc basis. At a specific site management level, China lacks capabilities in site investigation and consequent risk assessment systems, in particular related to conceptual modelling and risk evaluation. There is also a lack of shared experience of practical deployment of remediation technologies in China, analogous to the situation before the establishment of the independent, non-profit organisation CL:AIRE (Contaminated Land: Applications In Real Environments) in 1999 in the UK. Many local technology developments are at lab-scale or pilot-scale stage without being widely put into use. Therefore, a shared endeavour is needed to promote the development of technically and scientifically sound land management as well as soil and human health protection to improve the sustainability of the rapid urbanisation in China. PMID:26970591

  19. China's soil and groundwater management challenges: Lessons from the UK's experience and opportunities for China.

    PubMed

    Coulon, Frédéric; Jones, Kevin; Li, Hong; Hu, Qing; Gao, Jingyang; Li, Fasheng; Chen, Mengfang; Zhu, Yong-Guan; Liu, Rongxia; Liu, Ming; Canning, Kate; Harries, Nicola; Bardos, Paul; Nathanail, Paul; Sweeney, Rob; Middleton, David; Charnley, Maggie; Randall, Jeremy; Richell, Martin; Howard, Trevor; Martin, Ian; Spooner, Simon; Weeks, Jason; Cave, Mark; Yu, Fang; Zhang, Fang; Jiang, Ying; Longhurst, Phil; Prpich, George; Bewley, Richard; Abra, Jonathan; Pollard, Simon

    2016-05-01

    There are a number of specific opportunities for UK and China to work together on contaminated land management issues as China lacks comprehensive and systematic planning for sustainable risk based land management, encompassing both contaminated soil and groundwater and recycling and reuse of soil. It also lacks comprehensive risk assessment systems, structures to support risk management decision making, processes for verification of remediation outcome, systems for record keeping and preservation and integration of contamination issues into land use planning, along with procedures for ensuring effective health and safety considerations during remediation projects, and effective evaluation of costs versus benefits and overall sustainability. A consequence of the absence of these overarching frameworks has been that remediation takes place on an ad hoc basis. At a specific site management level, China lacks capabilities in site investigation and consequent risk assessment systems, in particular related to conceptual modelling and risk evaluation. There is also a lack of shared experience of practical deployment of remediation technologies in China, analogous to the situation before the establishment of the independent, non-profit organisation CL:AIRE (Contaminated Land: Applications In Real Environments) in 1999 in the UK. Many local technology developments are at lab-scale or pilot-scale stage without being widely put into use. Therefore, a shared endeavour is needed to promote the development of technically and scientifically sound land management as well as soil and human health protection to improve the sustainability of the rapid urbanisation in China.

  20. [Relationships between typical vegetations, soil salinity, and groundwater depth in the Yellow River Delta of China].

    PubMed

    Ma, Yu-Lei; Wang, De; Liu, Jun-Min; Wen, Xiao-Hu; Gao, Meng; Shao, Hong-Bo

    2013-09-01

    Soil salinity and groundwater depth are the two important factors affecting the vegetation growth and distribution in the Yellow River Delta. Through field investigation and statistical analysis, this paper studied the relationships between the typical vegetations (Suaeda heteroptera-Tamarix chinensis, Robinia pseudoacacia, Phragmites australis, and cotton) , soil salinity, and groundwater depth in the Delta. In the study area, groundwater depth had significant effects on soil salinity, with the average influence coefficient being 0.327. When the groundwater depth was 0.5-1.5 m, soil salinization was most severe. The vegetation growth in the Delta was poorer, with the NDVI in 78% of the total area being less than 0.4. Groundwater depth and soil salinity had significant effects on the vegetation distribution. Soil salinity had significant effects on the NDVI of R. pseudoacacia, S. heteroptera-T. chinensis, P. australis, and cotton, while groundwater depth had significant effects on the NDVI of S. heteroptera - T. chinensis, but lesser effects on the NDVI of P. australis, cotton and R. pseudoacacia.

  1. Groundwater.

    ERIC Educational Resources Information Center

    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)

  2. Monitoring the Perturbation of Soil and Groundwater Microbial Communities Due to Pig Production Activities

    PubMed Central

    Hong, Pei-Ying; Yannarell, Anthony C.; Dai, Qinghua; Ekizoglu, Melike

    2013-01-01

    This study aimed to determine if biotic contaminants originating from pig production farms are disseminated into soil and groundwater microbial communities. A spatial and temporal sampling of soil and groundwater in proximity to pig production farms was conducted, and quantitative PCR (Q-PCR) was utilized to determine the abundances of tetracycline resistance genes (i.e., tetQ and tetZ) and integrase genes (i.e., intI1 and intI2). We observed that the abundances of tetZ, tetQ, intI1, and intI2 in the soils increased at least 6-fold after manure application, and their abundances remained elevated above the background for up to 16 months. Q-PCR further determined total abundances of up to 5.88 × 109 copies/ng DNA for tetZ, tetQ, intI1, and intI2 in some of the groundwater wells that were situated next to the manure lagoon and in the facility well used to supply water for one of the farms. We further utilized 16S rRNA-based pyrosequencing to assess the microbial communities, and our comparative analyses suggest that most of the soil samples collected before and after manure application did not change significantly, sharing a high Bray-Curtis similarity of 78.5%. In contrast, an increase in Bacteroidetes and sulfur-oxidizing bacterial populations was observed in the groundwaters collected from lagoon-associated groundwater wells. Genera associated with opportunistic human and animal pathogens, such as Acinetobacter, Arcobacter, Yersinia, and Coxiella, were detected in some of the manure-treated soils and affected groundwater wells. Feces-associated bacteria such as Streptococcus, Erysipelothrix, and Bacteroides were detected in the manure, soil, and groundwater ecosystems, suggesting a perturbation of the soil and groundwater environments by invader species from pig production activities. PMID:23396341

  3. Monitoring of Nitrate and Pesticide Pollution in Mnasra, Morocco Soil and Groundwater.

    PubMed

    Marouane, Bouchra; Dahchour, Abdelmalek; Dousset, Sylvie; El Hajjaji, Souad

    2015-06-01

    This study evaluates the levels of nitrates and pesticides occurring in groundwater and agricultural soil in the Mnasra, Morocco area, a zone with intensive agricultural activity. A set of 108 water samples and 68 soil samples were collected from ten selected sites in the area during agricultural seasons, from May 2010 to September 2012. The results reveal that 89.7% of water samples exceeded the standard limit of nitrate concentrations for groundwater (50 mg/L). These results can be explained by the prevailing sandy nature of the soil in the area, the frequency of fertilizer usage, and the shallow level of the water table, which favors the leaching of nitrate from field to groundwater. In contrast, the selected pesticide molecules were not detected in the analysed soil and water samples; levels were below the quantification limit in all samples. This situation could be explained by the probable partial or total transformation of the molecules in soil.

  4. Monitoring of Nitrate and Pesticide Pollution in Mnasra, Morocco Soil and Groundwater.

    PubMed

    Marouane, Bouchra; Dahchour, Abdelmalek; Dousset, Sylvie; El Hajjaji, Souad

    2015-06-01

    This study evaluates the levels of nitrates and pesticides occurring in groundwater and agricultural soil in the Mnasra, Morocco area, a zone with intensive agricultural activity. A set of 108 water samples and 68 soil samples were collected from ten selected sites in the area during agricultural seasons, from May 2010 to September 2012. The results reveal that 89.7% of water samples exceeded the standard limit of nitrate concentrations for groundwater (50 mg/L). These results can be explained by the prevailing sandy nature of the soil in the area, the frequency of fertilizer usage, and the shallow level of the water table, which favors the leaching of nitrate from field to groundwater. In contrast, the selected pesticide molecules were not detected in the analysed soil and water samples; levels were below the quantification limit in all samples. This situation could be explained by the probable partial or total transformation of the molecules in soil. PMID:26459825

  5. Impact of long-term land application of biosolids on groundwater quality and surface soils

    SciTech Connect

    Surampalli, R.Y.; Lin, K.L.; Banerji, S.K.

    1995-11-01

    A study was conducted to evaluate the long-term land application of Biosolids and its potential impact on groundwater quality and surface soils. For this study, an existing site, that has been in operation for 8--15 years were selected for sampling and analyses. From this site sludge applied soil samples, background soil samples, and groundwater monitoring samples were obtained. The samples were analyzed for the following: pH, conductivity, total solids, fecal coliform, fecal streptococci, nitrate nitrogen, ammonia nitrogen, TKN, arsenic, cadmium, chromium, copper, nickel, lead, and zinc. The results of this study indicate that groundwater at this biosolids application site was not contaminated with heavy metals or pathogens. The bacteriological soil data also indicated that the levels of fecal coliform and fecal streptococci were close to background level with no evidence of contamination. The results also indicate that there is no heavy metals buildup in biosolids-amended soils.

  6. Developments in in situ biorestoration of contaminated soil and groundwater in the Netherlands.

    PubMed

    Staps, J J

    1989-01-01

    This paper considers the actual state of the art of in-situ biorestoration of contaminated soil and groundwater in the Netherlands. After a description of the relevant research programme, some research projects are described. These concern stimulation of biodegradation by means of venting and circulation of water for addition of oxygen and nutrients. Furthermore, some information about treatment of contaminated soil and groundwater on full scale is given. For groundwater, some activities on research of biological treatment systems for specific pollutants are mentioned. PMID:2658037

  7. Contributions of groundwater conditions to soil and water salinization

    NASA Astrophysics Data System (ADS)

    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

  8. Soil characteristics and agrichemicals in groundwater of the Midwestern United States

    USGS Publications Warehouse

    Burkart, M.; Kolpin, D.W.; Jaquis, R.J.; Cole, K.

    2001-01-01

    A comprehensive set of soil characteristics were examined to determine the effect of soil on the transport of agrichemicals to groundwater. This paper examines the relation of soil characteristics to concentrations and occurrence nitrate, atrazine, and atrazine residue from 99 wells completed in unconsolidated aquifers across the Midwestern United States. Soil characteristics that determine the rate of water movement were directly related to the occurrence and concentrations of nitrate and atrazine in groundwater. The substantial differences in the relations found among soil characteristics and nitrate and atrazine in groundwater suggest that different processes affect the transformation, adsorption, and transport of these contaminants. A multi-variable analysis determined that the soil characteristics examined explained the amount of variability in concentrations for nitrate (19%), atrazine (33%), and atrazine residue (29%). These results document that, although soils do affect the transport of agrichemicals to groundwater, other factors such as hydrology, land use, and climate must also be considered to understand the occurrence of agrichemicals in groundwater.

  9. Pesticides in western Canadian mountain air and soil.

    PubMed

    Daly, Gillian L; Lei, Ying D; Teixeira, Camilla; Muir, Derek C G; Wania, Frank

    2007-09-01

    The distribution of organochlorine pesticides (OCP; in past and current use) in the mountains of western Canada was determined by sampling air, soil, and lichen along three elevational transects in 2003-2004. Two transects west of the Continental Divide were located in Mount Revelstoke and Yoho National Park, while the Observation Peak transect in Banff National Park is east of the divide. XAD-based passive air samplers, yielding annually averaged air concentrations, were deployed, and soils were collected at all 22 sampling sites, whereas lichen were only sampled in Revelstoke. Back trajectory analysis showed limited air mass transport from the Prairies to the east, but a high frequency of air arriving from the southwest, which includes agricultural regions in British Columbia and Washington State. Endosulfan, dieldrin, and a-hexachlorocyclohexane were the most prevalent OCPs in air and soil; hexachlorobenzene was only abundant in air; chlorothalonil, dacthal, and pentachloronitrobenzene were also consistently present. OCP air concentrations were similar across the three transects, suggesting efficient atmospheric mixing on a local and regional scale. Soil concentrations and soil/air concentration ratios of many OCPs were significantly higher west of the Continental Divide. The soil and lichen concentrations of most OCPs increased with altitude in Revelstoke, and displayed maxima at intermediate elevations at Yoho and Observation Peak. These distribution patterns can be understood as being determined by the balance between atmospheric deposition to, and retention within, the soils. Higher deposition, due to more precipitation falling at lower temperatures, likely occurs west of the divide and at higher elevations. Higher retention, due to higher soil organic matter content, is believed to occur in soils below the tree line. Highest pesticide concentrations are thus found intemperate mountain soils that are rich in organic matter and receive large amounts of cold

  10. Relationships between basic soils-engineering equations and basic ground-water flow equations

    USGS Publications Warehouse

    Jorgensen, Donald G.

    1980-01-01

    The many varied though related terms developed by ground-water hydrologists and by soils engineers are useful to each discipline, but their differences in terminology hinder the use of related information in interdisciplinary studies. Equations for the Terzaghi theory of consolidation and equations for ground-water flow are identical under specific conditions. A combination of the two sets of equations relates porosity to void ratio and relates the modulus of elasticity to the coefficient of compressibility, coefficient of volume compressibility, compression index, coefficient of consolidation, specific storage, and ultimate compaction. Also, transient ground-water flow is related to coefficient of consolidation, rate of soil compaction, and hydraulic conductivity. Examples show that soils-engineering data and concepts are useful to solution of problems in ground-water hydrology.

  11. Groundwater recharge assessment at local and episodic scale in a soil mantled perched karst aquifer in southern Italy

    NASA Astrophysics Data System (ADS)

    Allocca, V.; De Vita, P.; Manna, F.; Nimmo, J. R.

    2015-10-01

    Groundwater recharge assessment of karst aquifers, at various spatial and temporal scales, is a major scientific topic of current importance, since these aquifers play an essential role for both socio-economic development and fluvial ecosystems. In this study, groundwater recharge was estimated at local and episodic scales in a representative perched karst aquifer in a region of southern Italy with a Mediterranean climate. The research utilized measurements of precipitation, air temperature, soil water content, and water-table depth, obtained in 2008 at the Acqua della Madonna test area (Terminio Mount karst aquifer, Campania region). At this location the aquifer is overlain by ash-fall pyroclastic soils. The Episodic Master Recession (EMR) method, an improved version of the Water Table Fluctuation (WTF) method, was applied to estimate the amount of recharge generated episodically by individual rainfall events. The method also quantifies the amount of precipitation generating each recharge episode, thus permitting calculation of the Recharge to the Precipitation Ratio (RPR) on a storm-by-storm basis. Depending on the seasonally varying air temperature, evapotranspiration, and precipitation patterns, calculated values of RPR varied between 35% and 97% among the individual episodes. A multiple linear correlation of the RPR with both the average intensity of recharging rainfall events and the antecedent soil water content was calculated. Given the relatively easy measurability of precipitation and soil water content, such an empirical model would have great hydrogeological and practical utility. It would facilitate short-term forecasting of recharge in karst aquifers of the Mediterranean region and other aquifers with similar hydrogeological characteristics. By establishing relationships between the RPR and climate-dependent variables such as average storm intensity, it would facilitate prediction of climate-change effects on groundwater recharge. The EMR methodology

  12. Total petroleum hydrocarbon distribution in soils and groundwater in Songyuan oilfield, Northeast China.

    PubMed

    Teng, Yanguo; Feng, Dan; Song, Liuting; Wang, Jinsheng; Li, Jian

    2013-11-01

    In order to investigate the distribution of the total petroleum hydrocarbons (TPH) in groundwater and soil, a total of 71 groundwater samples (26 unconfined groundwater samples, 37 confined groundwater samples, and 8 deeper confined groundwater samples) and 80 soil samples were collected in the Songyuan oilfield, Northeast China, and the vertical variation and spatial variability of TPH in groundwater and soil were assessed. For the groundwater from the unconfined aquifer, petroleum hydrocarbons were not detected in three samples, and for the other 23 samples, concentrations were in the range 0.01-1.74 mg/l. In the groundwater from the confined aquifer, petroleum hydrocarbons were not detected in two samples, and in the other 35 samples, the concentrations were 0.04-0.82 mg/l. The TPH concentration in unconfined aquifer may be influenced by polluted surface water and polluted soil; for confined aquifer, the injection wells leakage and left open hole wells may be mainly responsible for the pollution. For soils, the concentrations of TPH varied with sampling depth and were 0-15 cm (average concentration, 0.63 mg/g), >40-55 cm (average concentration, 0.36 mg/g), >100-115 cm (average concentration, 0.29 mg/g), and >500-515 cm (average concentration, 0.26 mg/g). The results showed that oil spillage and losses were possibly the main sources of TPH in soil. The consequences concluded here suggested that counter measures such as remediation and long-term monitoring should be commenced in the near future, and effective measures should be taken to assure that the oilfields area would not be a threat to human health.

  13. APPLICATION STRATEGIES AND DESIGN CRITERIA FOR IN SITU BIOREMEDIATION OF SOIL AND GROUNDWATER IMPACTED BY PAHS

    EPA Science Inventory

    Biotreatability studies conducted in our laboratory used soils from two former wood-treatment facilities to evaluate the use of in situ bioventing and biosparging applications for their potential ability to remediate soil and groundwater containing creosote. The combination of ph...

  14. Ground-water and soil contamination near two pesticide-burial sites in Minnesota

    USGS Publications Warehouse

    Stark, J.R.; Strudell, J.D.; Bloomgren, P.A.; Eger, P.

    1987-01-01

    In general, concentrations of lead and arsenic in soil and groundwater were below background concentrations for the areas. Concentrations of organic pesticides generally were below analytical-detection limits. The limited solubility of the chemicals and the tendency of the contaminants to be sorbed on soil particles probably combined to restrict mobilization of the chemicals.

  15. Greenhouse gas emission and groundwater pollution potentials of soils amended with different swine biochars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to study the greenhouse gas emission and groundwater pollution potentials of the soils amended with various biochars using different biomass feedstocks and thermal processing conditions. Triplicate sets of small pots were designed; control soil consisting of Histi...

  16. Greenhouse gas emission and groundwater pollution potentials of soils amended with raw and carbonized swine solids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research is to study the greenhouse gas emission and groundwater pollution potentials of the soils amended with raw swine solids and swine biochars made from different thermochemical conditions. Triplicate sets of small pots were designed: 1) control soil with a 50/50 mixture o...

  17. Dissipation of the herbicide oxyfluorfen in subtropical soils and its potential to contaminate groundwater.

    PubMed

    Yen, Jui-Hung; Sheu, Wey-Shin; Wang, Yei-Shung

    2003-02-01

    The dissipation and mobility of the herbicide oxyfluorfen (2-chloro-alpha,alpha,alpha-trifluoro-p-tolyl 3-ethoxy-4-nitrophenyl ether) in field soil of Taiwan were investigated in the laboratory with six tea garden soils. The dissipation coefficients of oxyfluorfen in soils of different moisture content (30%, 60%, and 90% of soil field capacity) and soil temperature (10 degrees C, 25 degrees C, and 40 degrees C) were studied. Results indicate that the half-life of oxyfluorfen ranged from 72 to 160 days for six tea garden soils. It was found that if the temperature is high, the dissipation rate is rapid, and there is almost no dissipation at 10 degrees C. Possible contamination of groundwater by the herbicide oxyfluorfen was assessed using the behavior assessment model and the groundwater pollution-potential (GWP) model. The results obtained after evaluating the residue and travel time using the GWP model illustrated that oxyfluorfen is not very mobile in soil and may not contaminate groundwater under normal conditions. But in the case of soil of extremely low organic carbon content and coarse texture, oxyfluorfen has the potential to contaminate groundwater less than 3m deep.

  18. Environmental impacts on soil and groundwater at airports: origin, contaminants of concern and environmental risks.

    PubMed

    Nunes, L M; Zhu, Y-G; Stigter, T Y; Monteiro, J P; Teixeira, M R

    2011-11-01

    Environmental impacts of airports are similar to those of many industries, though their operations expand over a very large area. Most international impact assessment studies and environmental management programmes have been giving less focus on the impacts to soil and groundwater than desirable. This may be the result of the large attention given to air and noise pollution, relegating other environmental descriptors to a second role, even when the first are comparatively less relevant. One reason that contributes to such "biased" evaluation is the lack of systematic information about impacts to soil and groundwater from airport activities, something the present study intends to help correct. Results presented here include the review of over seven hundred documents and online databases, with the objective of obtaining the following information to support environmental studies: (i) which operations are responsible for chemical releases?; (ii) where are these releases located?; (iii) which contaminants of concern are released?; (iv) what are the associated environmental risks? Results showed that the main impacts occur as a result of fuel storage, stormwater runoff and drainage systems, fuel hydrant systems, fuel transport and refuelling, atmospheric deposition, rescue and fire fighting training areas, winter operations, electrical substations, storage of chemical products by airport owners or tenants, and maintenance of green areas. A new method for ranking environmental risks of organic substances, based on chemical properties, is proposed and applied. Results show that the contaminants with the highest risks are the perfluorochemicals, benzene, trichloroethylene and CCl(4). The obtained information provides a basis for establishing the planning and checking phases of environmental management systems, and may also help in the best design of pollution prevention measures in order to avoid or reduce significant environmental impacts from airports.

  19. Hazardous concentrations of selenium in soil and groundwater in North-West India.

    PubMed

    Bajaj, Mini; Eiche, Elisabeth; Neumann, Thomas; Winter, Josef; Gallert, Claudia

    2011-05-30

    Soil and groundwater samples were collected for bulk elemental analyses in particular for selenium (Se) concentrations from six agricultural sites located in states of Punjab and Haryana in North-West India. Toxic concentrations of Se (45-341 μg L(-1)) were present in groundwater (76 m deep) of Jainpur and Barwa villages in Punjab. Selenium enrichments were also found in top soil layers (0-15 cm) of Jainpur (2.3-11.6 mg kg(-1)) and Barwa (3.1 mg kg(-1)). Mineralogical analyses confirmed silicates and phyllosilicates as main components of these soils, also reflected by the high content of SiO(2) (40-62 wt.%), Al(2)O(3) (9-21 wt.%) and K(2)O (2.2-3.2 wt.%). Prevailing intensive irrigation practices in Punjab with Se enriched groundwater may be the cause of Se accumulation in soils. Sequential extraction revealed >50% Se bioavailability in Jainpur soils. Appearance of selenite was observed in some of the batch assays with soil slurries under reducing conditions. Although safe Se concentrations were found in Hisar, Haryana, yet high levels of As, Mo and U present in groundwater indicated its unsuitability for drinking purposes. Detailed biogeochemical studies of Se in sediments or groundwater of Punjab are not available so far; intensive investigations should be started for better understanding of the problem of Se toxicity.

  20. SWB-A modified Thornthwaite-Mather Soil-Water-Balance code for estimating groundwater recharge

    USGS Publications Warehouse

    Westenbroek, S.M.; Kelson, V.A.; Dripps, W.R.; Hunt, R.J.; Bradbury, K.R.

    2010-01-01

    A Soil-Water-Balance (SWB) computer code has been developed to calculate spatial and temporal variations in groundwater recharge. The SWB model calculates recharge by use of commonly available geographic information system (GIS) data layers in combination with tabular climatological data. The code is based on a modified Thornthwaite-Mather soil-water-balance approach, with components of the soil-water balance calculated at a daily timestep. Recharge calculations are made on a rectangular grid of computational elements that may be easily imported into a regional groundwater-flow model. Recharge estimates calculated by the code may be output as daily, monthly, or annual values.

  1. Applying membrane technology to air stripping effluent for remediation of groundwater contaminated with volatile organic compounds

    SciTech Connect

    Brown, J.J.; Erickson, M.D.; Beskid, N.J.

    1993-12-31

    Remediation groundwater contaminated by volatile organic compounds (VOCs) requires cost- and technically-effective solutions. This paper reviews the options for VOC removal from remediation air streams, focusing on membrane separation. The basic separation science and technology, results of performance tests, and results of cost studies for membrane separation are presented. Competing technologies are discussed and compared with membrane separation. Membrane separation combined with air stripping will provide an economically and environmentally safe technology for remediation of VOC-contaminated groundwater and, as it matures, may become the preferred method. 9 refs., 6 figs., 2 tabs.

  2. Responses of Water and Salt Parameters to Groundwater Levels for Soil Columns Planted with Tamarix chinensis.

    PubMed

    Xia, Jiangbao; Zhao, Ximei; Chen, Yinping; Fang, Ying; Zhao, Ziguo

    2016-01-01

    Groundwater is the main water resource for plant growth and development in the saline soil of the Yellow River Delta in China. To investigate the variabilities and distributions of soil water and salt contents at various groundwater level (GL), soil columns with planting Tamarix chinensis Lour were established at six different GL. The results demonstrated the following: With increasing GL, the relative soil water content (RWC) declined significantly, whereas the salt content (SC) and absolute soil solution concentration (CS) decreased after the initial increase in the different soil profiles. A GL of 1.2 m was the turning point for variations in the soil water and salt contents, and it represented the highest GL that could maintain the soil surface moist within the soil columns. Both the SC and CS reached the maximum levels in these different soil profiles at a GL of 1.2 m. With the raise of soil depth, the RWC increased significantly, whereas the SC increased after an initial decrease. The mean SC values reached 0.96% in the top soil layer; however, the rates at which the CS and RWC decreased with the GL were significantly reduced. The RWC and SC presented the greatest variations at the medium (0.9-1.2 m) and shallow water levels (0.6 m) respectively, whereas the CS presented the greatest variation at the deep water level (1.5-1.8 m).The RWC, SC and CS in the soil columns were all closely related to the GL. However, the correlations among the parameters varied greatly within different soil profiles, and the most accurate predictions of the GL were derived from the RWC in the shallow soil layer or the SC in the top soil layer. A GL at 1.5-1.8 m was moderate for planting T. chinensis seedlings under saline groundwater conditions.

  3. Responses of Water and Salt Parameters to Groundwater Levels for Soil Columns Planted with Tamarix chinensis

    PubMed Central

    Xia, Jiangbao; Zhao, Ximei; Chen, Yinping; Fang, Ying; Zhao, Ziguo

    2016-01-01

    Groundwater is the main water resource for plant growth and development in the saline soil of the Yellow River Delta in China. To investigate the variabilities and distributions of soil water and salt contents at various groundwater level (GL), soil columns with planting Tamarix chinensis Lour were established at six different GL. The results demonstrated the following: With increasing GL, the relative soil water content (RWC) declined significantly, whereas the salt content (SC) and absolute soil solution concentration (CS) decreased after the initial increase in the different soil profiles. A GL of 1.2 m was the turning point for variations in the soil water and salt contents, and it represented the highest GL that could maintain the soil surface moist within the soil columns. Both the SC and CS reached the maximum levels in these different soil profiles at a GL of 1.2 m. With the raise of soil depth, the RWC increased significantly, whereas the SC increased after an initial decrease. The mean SC values reached 0.96% in the top soil layer; however, the rates at which the CS and RWC decreased with the GL were significantly reduced. The RWC and SC presented the greatest variations at the medium (0.9–1.2 m) and shallow water levels (0.6 m) respectively, whereas the CS presented the greatest variation at the deep water level (1.5–1.8 m).The RWC, SC and CS in the soil columns were all closely related to the GL. However, the correlations among the parameters varied greatly within different soil profiles, and the most accurate predictions of the GL were derived from the RWC in the shallow soil layer or the SC in the top soil layer. A GL at 1.5–1.8 m was moderate for planting T. chinensis seedlings under saline groundwater conditions. PMID:26730602

  4. FIELD TEST OF AIR SPARGING COUPLED WITH SOIL VAPOR EXTRACTION

    EPA Science Inventory

    A controlled field study was designed and conducted to assess the performance of air sparging for remediation of petroleum fuel and solvent contamination in a shallow (3-m deep) groundwater aquifer. Sparging was performed in an insolation test cell (5 m by 3 m by 8-m deep). A soi...

  5. Comparison of soil solution sampling techniques to assess metal fluxes from contaminated soil to groundwater.

    PubMed

    Coutelot, F; Sappin-Didier, V; Keller, C; Atteia, O

    2014-12-01

    The unsaturated zone plays a major role in elemental fluxes in terrestrial ecosystems. A representative chemical analysis of soil pore water is required for the interpretation of soil chemical phenomena and particularly to assess Trace Elements (TEs) mobility. This requires an optimal sampling system to avoid modification of the extracted soil water chemistry and allow for an accurate estimation of solute fluxes. In this paper, the chemical composition of soil solutions sampled by Rhizon® samplers connected to a standard syringe was compared to two other types of suction probes (Rhizon® + vacuum tube and Rhizon® + diverted flow system). We investigated the effects of different vacuum application procedures on concentrations of spiked elements (Cr, As, Zn) mixed as powder into the first 20 cm of 100-cm columns and non-spiked elements (Ca, Na, Mg) concentrations in two types of columns (SiO2 sand and a mixture of kaolinite + SiO2 sand substrates). Rhizon® was installed at different depths. The metals concentrations showed that (i) in sand, peak concentrations cannot be correctly sampled, thus the flux cannot be estimated, and the errors can easily reach a factor 2; (ii) in sand + clay columns, peak concentrations were larger, indicating that they could be sampled but, due to sorption on clay, it was not possible to compare fluxes at different depths. The different samplers tested were not able to reflect the elemental flux to groundwater and, although the Rhizon® + syringe device was more accurate, the best solution remains to be the use of a lysimeter, whose bottom is kept continuously at a suction close to the one existing in the soil. PMID:25277861

  6. Comparison of soil solution sampling techniques to assess metal fluxes from contaminated soil to groundwater.

    PubMed

    Coutelot, F; Sappin-Didier, V; Keller, C; Atteia, O

    2014-12-01

    The unsaturated zone plays a major role in elemental fluxes in terrestrial ecosystems. A representative chemical analysis of soil pore water is required for the interpretation of soil chemical phenomena and particularly to assess Trace Elements (TEs) mobility. This requires an optimal sampling system to avoid modification of the extracted soil water chemistry and allow for an accurate estimation of solute fluxes. In this paper, the chemical composition of soil solutions sampled by Rhizon® samplers connected to a standard syringe was compared to two other types of suction probes (Rhizon® + vacuum tube and Rhizon® + diverted flow system). We investigated the effects of different vacuum application procedures on concentrations of spiked elements (Cr, As, Zn) mixed as powder into the first 20 cm of 100-cm columns and non-spiked elements (Ca, Na, Mg) concentrations in two types of columns (SiO2 sand and a mixture of kaolinite + SiO2 sand substrates). Rhizon® was installed at different depths. The metals concentrations showed that (i) in sand, peak concentrations cannot be correctly sampled, thus the flux cannot be estimated, and the errors can easily reach a factor 2; (ii) in sand + clay columns, peak concentrations were larger, indicating that they could be sampled but, due to sorption on clay, it was not possible to compare fluxes at different depths. The different samplers tested were not able to reflect the elemental flux to groundwater and, although the Rhizon® + syringe device was more accurate, the best solution remains to be the use of a lysimeter, whose bottom is kept continuously at a suction close to the one existing in the soil.

  7. Pollution potential of oil-contaminated soil on groundwater resources in Kuwait.

    PubMed

    Literathy, P; Quinn, M; Al-Rashed, M

    2003-01-01

    The only natural freshwater resource of Kuwait occurs as lenses floating on the saline groundwater in the northern part of the country, near to the oil fields. Rainwater is the only means of recharge of this limited groundwater resource. This groundwater is used as bottled drinking water and the fresh groundwater aquifer is considered as a strategic drinking water reserve for Kuwait. As a result of the 1991 Gulf War, the upper soil layer has been widely contaminated with crude oil and crude oil combustion products, which are potential pollutants likely affecting the groundwater resources. Significant efforts have been made to assess this pollution. These included: (a) a soil survey for assessing the soil contamination, and (b) leaching experiments to characterise the mobilization of the soil-associated pollutants. Fluorescence measurement techniques were used during field surveys as well as for laboratory testing. In addition, determination of the total extractable matter (TEM), total petroleum hydrocarbons (TPH), and GC/MS measurement of polyaromatic hydrocarbons (PAHs) were performed for the assessments. The laser induced fluorescence (LIF) measurement, having good correlation with the other laboratory measurements, was proved to provide necessary information for the assessment of the oil-contamination level in the desert soil. The subsequent leaching test with water demonstrated the mobilization of the fluorescing compounds (e.g. PAHs), and the alteration in the leaching characteristics of the contamination during the long-term environmental weathering of the oil.

  8. 3D modeling of soil structure in urban groundwater areas: case studies in Kolpene, Rovaniemi, Finland

    NASA Astrophysics Data System (ADS)

    Kupila, Juho

    2015-04-01

    3D modeling of groundwater areas is an important research method in groundwater surveys. Model of geological soil structure improves the knowledge of linkage between land use planning and groundwater protection. Results can be used as base information when developing the water supply services and anticipating and performing the measures needed in case of environmental accidents. Also, collected information is utilized when creating the groundwater flow model. In Finland, structure studies have been conducted in cooperation (among others) with the municipalities and local water suppliers and with the authorities from the Centre for Economic Development, Transport and the Environment. Geological Survey of Finland carries out project "Structure studies in Kolpene groundwater area" in Rovaniemi, Finnish Lapland. Study site is located in northern Finland, in the vicinity of the city center of Rovaniemi. Extent of the area is about 13 square kilometers and there are lots of urban residential areas and other human activities. The objective of this project is to determine the geological structure of the Kolpene groundwater area so that the results can be used to estimate the validity of the present exclusion area and possible risks to the groundwater caused by the land use. Soil layers of the groundwater area are studied by means of collecting information by heavy drilling, geophysical surveying (ground penetrating radar and gravimeter measurements) and water sampling from the installed observation pipes. Also the general geological and hydrological mappings are carried out. Main results which will be produced are: 1) the model of the bedrock surface, 2) the model of the surface of the ground water and flow directions, 3) the thickness of ground water saturated soil layers and 4) location and main characteristics of the soil layers which are significant to the ground water conditions. The preparing studies have been started at the end of 2013 and the results will be

  9. Influence of long-term sewage irrigation on the distribution of organochlorine pesticides in soil-groundwater systems.

    PubMed

    Zhang, Caixiang; Liao, Xiaoping; Li, Jiale; Xu, Liang; Liu, Ming; Du, Bin; Wang, Yanxin

    2013-07-01

    Serious shortage of water resources is one of the major factors restricting the sustainable development of cropland and pasture land in northern and northwestern China. Although the reuse of wastewater for agricultural irrigation becomes a well established practice in these regions, many contaminants have been also introduced into the soil-groundwater systems such as persistent organochlorine pesticides (OCPs). To study the influence of long-term sewage irrigation on the distribution of OCPs in soil-groundwater systems, the groundwater flow field was investigated and 31 topsoil samples, 9 boreholes, 11 sewage effluents and 34 groundwater samples were collected in Xiaodian, Taiyuan city, one of the largest sewage irrigation districts, China. During sampling, three representative types of regions were considered including effluent-irrigated area, groundwater-irrigated area served as the control field and no-irrigated area as reference "background". The results showed over-exploitation of groundwater had changed the flow field of groundwater and wherever in soil or in groundwater, the concentration of OCPs in effluent-irrigation area presented the highest value, which indicated that the sewage irrigation had a strong influence on the distribution of OCPs in soil-groundwater systems. Principal component analysis for OCPs content in groundwater showed that the major influence factors on the occurrence and distribution of OCPs in groundwater systems attribute to the flow field of groundwater and to the current pesticide use.

  10. Recovery of soil water, groundwater, and streamwater from acidification at the Swedish integrated monitoring catchments.

    PubMed

    Löfgren, Stefan; Aastrup, Mats; Bringmark, Lage; Hultberg, Hans; Lewin-Pihlblad, Lotta; Lundin, Lars; Karlsson, Gunilla Pihl; Thunholm, Bo

    2011-12-01

    Recovery from anthropogenic acidification in streams and lakes is well documented across the northern hemisphere. In this study, we use 1996-2009 data from the four Swedish Integrated Monitoring catchments to evaluate how the declining sulfur deposition has affected sulfate, pH, acid neutralizing capacity, ionic strength, aluminum, and dissolved organic carbon in soil water, groundwater and runoff. Differences in recovery rates between catchments, between recharge and discharge areas and between soil water and groundwater are assessed. At the IM sites, atmospheric deposition is the main human impact. The chemical trends were weakly correlated to the sulfur deposition decline. Other factors, such as marine influence and catchment features, seem to be as important. Except for pH and DOC, soil water and groundwater showed similar trends. Discharge areas acted as buffers, dampening the trends in streamwater. Further monitoring and modeling of these hydraulically active sites should be encouraged. PMID:22201000

  11. Groundwater control of mangrove surface elevation: shrink and swell varies with soil depth

    USGS Publications Warehouse

    Whelan, K.R.T.; Smith, T. J.; Cahoon, D.R.; Lynch, J.C.; Anderson, G.H.

    2005-01-01

    We measured monthly soil surface elevation change and determined its relationship to groundwater changes at a mangrove forest site along Shark River, Everglades National Park, Florida. We combined the use of an original design, surface elevation table with new rod-surface elevation tables to separately track changes in the mid zone (0?4 m), the shallow root zone (0?0.35 m), and the full sediment profile (0?6 m) in response to site hydrology (daily river stage and groundwater piezometric pressure). We calculated expansion and contraction for each of the four constituent soil zones (surface [accretion and erosion; above 0 m], shallow zone [0?0.35 m], middle zone [0.35?4 m], and bottom zone [4?6 m]) that comprise the entire soil column. Changes in groundwater pressure correlated strongly with changes in soil elevation for the entire profile (Adjusted R2 5 0.90); this relationship was not proportional to the depth of the soil profile sampled. The change in thickness of the bottom soil zone accounted for the majority (R2 5 0.63) of the entire soil profile expansion and contraction. The influence of hydrology on specific soil zones and absolute elevation change must be considered when evaluating the effect of disturbances, sea level rise, and water management decisions on coastal wetland systems.

  12. Soil and groundwater attenuation factors for nitrogen from septic systems in the Chesapeake Bay TMDL

    NASA Astrophysics Data System (ADS)

    Radcliffe, D. E.; Geza, M.; O'Drisoll, M.; Humphrey, C., Jr.

    2015-12-01

    An expert panel was tasked with estimating the percent of the nitrogen (N) load from septic systems that was lost in the flow path from a typical home to third-order streams as part of the Chesapeake Bay Total Maximum Daily Load (TMDL). These losses were referred to as attenuation factors. We developed values for the soil (unsaturated) zone and for the Piedmont and Coastal Plain groundwater zones. For the soil zone, we used the Soil Treatment Unit MODel (STUMOD) to estimate loses due to denitrification for all 12 soil textural classes and then averaged the results over three textural groups. Assuming hydraulic loading at the design rate and a conventional system, the attenuation factors were 16% for sand, loamy sand, sandy loam, and loam soils; 34% for silt loam, clay loam, sandy clay loam, silty clay loam, and silt soils; and 54% for sandy clay, silty clay, and clay soils. Attenuation factors increased in the more clayey soils due to wetter conditions and more losses due to denitrification. Attenuation factors were also developed for reduced hydraulic loading rates and for systems using advanced N pre-treatment. For the Piedmont groundwater zone, we used data from a recent study in Georgia of small suburban streams with high-density septic systems. Stream base-flow load was estimated using simultaneous measurements of total N concentration and discharge and compared to the estimated groundwater input load, resulting in an attenuation factor of 81%. For the Coastal Plain groundwater zone, literature values of groundwater N concentrations within septic system plumes in Virginia, North Carolina, and Florida were used to estimate an attenuation factor of approximately 60% at 100m downgradient from the drainfield. These attenuation factors will be used to estimate the contribution of N to the Chesapeake Bay in the Phase 6 TMDL models.

  13. Assessment of the water exchange between soil and groundwater in an Alpine valley

    NASA Astrophysics Data System (ADS)

    Negm, Amro; Falocchi, Marco; Barontini, Stefano; Ranzi, Roberto; Bacchi, Baldassare

    2013-04-01

    The soil-water balance in temperate climates can be sensitively characterised by the water exchange between soil and groundwater. Particularly in mountain environments, where the soil and the water table depth are shallow, both percolation and water rise from the water table can happen, but these latter extimate is still a major challenge for hydrological applications. Aiming at contributing to better characterise the soil-water balance and the water exchange between soil and groundwater, at the local scale in an Alpine valley, a micrometeorological station was installed during summer 2012 at Cividate Camuno (Oglio river basin, Central Italian Alps, 274ma.s.l.), in a mountain environment with complex orography and Alpine sublitoranean climate. The soil upper layers, lying on an anthropised loose rock, are about 40cm deep and mainly covered by alfalfa (Medicago sativa), wild carrot (Daucus carota) and yarrow (Achillea millefolium). The station is equipped with longwave and shortwave radiometers, a thermo-hygrometer, two rain-gauges, eddy correlation devices (Gill WindMaster sonic anemometer and Licor Li7500 gas analyser, sampling at 20Hz), a TDR with multiplexer apparatus and four probes at different depths, three soil-thermometers and a heat exchanger plate. Field and laboratory tests were performed to characterise the main soil hydraulic properties (i.e. hydraulic conductivity at saturation by means of infiltration tests and falling head permeameter, porosity, residual water content and water content at saturation, soil-water retention relationships, organic matter content and grain size distribution curve). Three different hypothesis to model the water exchange between soil-water and groundwater were introduced. They are (i) a null exchange rate which accounts for a shortage of precipitation and for representing the underlying soil as a capillary barrier, (ii) a pure percolation with unitary gradient of the total hydraulic potential and (iii) a percolation or

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

    PubMed

    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.

  15. Groundwater recharge assessment at local and episodic scale in a soil mantled perched karst aquifer in southern Italy

    USGS Publications Warehouse

    Allocca, V.; De Vita, P.; Manna, F.; Nimmo, John R.

    2015-01-01

    Depending on the seasonally varying air temperature, evapotranspiration, and precipitation patterns, calculated values of RPR varied between 35% and 97% among the individual episodes. A multiple linear correlation of the RPR with both the average intensity of recharging rainfall events and the antecedent soil water content was calculated. Given the relatively easy measurability of precipitation and soil water content, such an empirical model would have great hydrogeological and practical utility. It would facilitate short-term forecasting of recharge in karst aquifers of the Mediterranean region and other aquifers with similar hydrogeological characteristics. By establishing relationships between the RPR and climate-dependent variables such as average storm intensity, it would facilitate prediction of climate-change effects on groundwater recharge. The EMR methodology could further be applied to other aquifers for evaluating the relationship of recharge to various hydrometeorological and hydrogeological processes.

  16. Treatment of TNT contaminated soil and groundwater using plant-based enzyme systems

    SciTech Connect

    Medina, V.F.; Wolfe, L.; McCutcheon, S.C.

    1995-12-31

    Trinitrotoluene (TNT) is considered toxic and a mutagen. For over 100 years, TNT has been widely used in explosives for both military and commercial applications. Soil and groundwater contamination by TNT is prevalent at military bases, manufacturing facilities and at commercial (such as mining) sites were TNT was used or stored. TNT is a difficult compound to treat. It is resistant to complete microbial degradation. Although incineration is feasible, it can be costly. One promising technology is degradation using plant enzyme systems, which has become known as phytoremediation. This paper will highlight bench and field studies of phytoremediation of TNT contaminated soil and groundwater. Parameters for developing a model will be discussed.

  17. Nitrate Distribution in Soil Moisture and Groundwater with Intensive Plantation Management on Abandoned Agricultural Land

    SciTech Connect

    Williams, T.M.

    1998-01-01

    Paper outlines nitrate leaching results of loblolly pine and sweet gum that were grown with irrigation, continuous fertilization and insect pest control on a year old abandoned peanut field. Wells and tension lysimeters were used to measure nitrate in soil moisture and groundwater on three replicate transects for two years. Groundwater nitrate concentration beneath the minimum treatment was much higher than the maximum treatment and old field. All three treatments often exceeded the drinking water standard. Forest and lake edge had low levels while the soil moisture nitrate concentrations in the two plantations treatments were much higher than the old field.

  18. A case study of the natural attenuation of gas condensate hydrocarbons in soil and groundwater.

    PubMed

    Barker, G W; Raterman, K T; Fisher, J B; Corgan, J M; Trent, G L; Brown, D R; Kemp, N; Sublette, K L

    1996-01-01

    Condensate liquids have been found to contaminate soil and groundwater at two gas production sites in the Denver Basin operated by Amoco Production Co. These sites have been closely monitored since July 1993 to determine whether intrinsic aerobic or anaerobic bioremediation of hydrocarbons occurs at a sufficient rate and to an adequate end point to support a no-intervention decision. Groundwater monitoring and analysis of soil cores suggest that intrinsic bioremediation is occurring at these sites by multiple pathways, including aerobic oxidation, Fe(III) reduction, and sulfate reduction.

  19. DUS II SOIL GAS SAMPLING AND AIR INJECTION TEST RESULTS

    SciTech Connect

    Noonkester, J.; Jackson, D.; Jones, W.; Hyde, W.; Kohn, J.; Walker, R.

    2012-09-20

    Soil vapor extraction (SVE) and air injection well testing was performed at the Dynamic Underground Stripping (DUS) site located near the M-Area Settling Basin (referred to as DUS II in this report). The objective of this testing was to determine the effectiveness of continued operation of these systems. Steam injection ended on September 19, 2009 and since this time the extraction operations have utilized residual heat that is present in the subsurface. The well testing campaign began on June 5, 2012 and was completed on June 25, 2012. Thirty-two (32) SVE wells were purged for 24 hours or longer using the active soil vapor extraction (ASVE) system at the DUS II site. During each test five or more soil gas samples were collected from each well and analyzed for target volatile organic compounds (VOCs). The DUS II site is divided into four parcels (see Figure 1) and soil gas sample results show the majority of residual VOC contamination remains in Parcel 1 with lesser amounts in the other three parcels. Several VOCs, including tetrachloroethylene (PCE) and trichloroethylene (TCE), were detected. PCE was the major VOC with lesser amounts of TCE. Most soil gas concentrations of PCE ranged from 0 to 60 ppmv with one well (VEW-22A) as high as 200 ppmv. Air sparging (AS) generally involves the injection of air into the aquifer through either vertical or horizontal wells. AS is coupled with SVE systems when contaminant recovery is necessary. While traditional air sparging (AS) is not a primary component of the DUS process, following the cessation of steam injection, eight (8) of the sixty-three (63) steam injection wells were used to inject air. These wells were previously used for hydrous pyrolysis oxidation (HPO) as part of the DUS process. Air sparging is different from the HPO operations in that the air was injected at a higher rate (20 to 50 scfm) versus HPO (1 to 2 scfm). . At the DUS II site the air injection wells were tested to determine if air sparging affected

  20. Treatment of contaminated groundwaters with granular activated carbon and air stripping

    SciTech Connect

    Stenzel, M.H.; Gupta, U.S.

    1985-01-01

    Over the past several years there have been increasing reports of cases of contaminated groundwater. Many cases were caused by leaking from surface impoundments or landfills, or leakage from underground storage tanks. Treatment of groundwater use, discharge or recharge into the aquifer is becoming a major concern. Two widely used treatment techniques are adsorption with granular activated carbon and packed tower air stripping. Granular activated carbon is often applied when organic contaminants need to be removed to nondetectable levels, and should be a part of the process if nonvolatile contaminants are present. Air stripping is capable of 95-99% reduction of volatile contaminants and can be a cost effective treatment technology if nondetectable contaminant levels are not required and air pollution is not a factor. Should off-gas from an air stripper require treatment for removal of organic contaminants, granular activated carbon adsorption can be effectively applied as it was in the water phase. Selection of a groundwater treatment technology depends on factors such as contaminant type, end use of the water and air pollution concern, and each case requires consideration of these factors to arrive at the most cost effective solution.

  1. Methodology of determining soil structure in important groundwater areas: case studies in Kauvonkangas, Finnish Lapland

    NASA Astrophysics Data System (ADS)

    Kupila, Juho

    2016-04-01

    Finland is fully self-sufficient in clean groundwater and even has a capacity of exportation. There are approx. 6000 groundwater areas with a total yield of 5.4 million m3/day. Currently only 10% of this groundwater resource is in use. For the efficient and safe exploitation of these areas in the future, detailed modeling of soil structure is an important method in groundwater surveys. 3D -models improve the general knowledge of linkage between land use planning and groundwater protection. Results can be used as a base information in water supply service development and when performing the measures needed in case of environmental accidents. Also, when creating the groundwater flow models the collected information is utilized and is usually the main data source. Geological Survey of Finland has carried out soil structure studies in co-operation with authorities, municipalities and the local water suppliers. The main objectives of these projects are to determine the geological structure of groundwater area for estimating the validity of the present exclusion area, the quantity of ground water volume and recharge capability and possible risks to the groundwater. Research areas are usually under an active water supply service. Kauvonkangas groundwater area is located in the municipality of Tervola, in Southern part of Finnish Lapland. Extent of the area is 7.9 km2 and it is an important water source for the local and nearby population centers. There are two active water supply companies in the area. Field studies in the project will include general geological and hydrological mapping, soil drilling with observation pipe installation, test pumping and water sampling. Geophysical measures will play a key-role, including ground penetrating radar (GPR) and gravimetric measurements. Studies will be carried out in spring and summer 2016. The main results will be the models of the bedrock and groundwater level and main characteristics of the soil layers in the area. Results

  2. Assessment of the insecticide carbofuran's potential to contaminate groundwater through soils in the subtropics.

    PubMed

    Yen, J H; Hsiao, F L; Wang, Y S

    1997-12-01

    The possible contamination of groundwater by the insecticide carbofuran was assessed with the behavior assessment model (BAM) and groundwater pollution-potential model (GWP). Dissipation coefficients of this insecticide in two subtropical soils at different moisture contents and soil temperatures were studied by determining the degradation and adsorption of the herbicide in soils. Movement of carbofuran was studied by leaching the insecticide in a soil column in the laboratory. Under 40% field capacity and at 25 degrees C, more than 80% of carbofuran residue was found in both Luchu clay and Yuanlin silty clay loam after incubation for 63 days. The results indicate that the higher the moisture content in the soil, the less the carbofuran residue under the soil moisture below the field capacity. Carbofuran tends to dissipate more easily in Yuanlin soil than in Luchu soil. The distribution coefficient (Kd) with r2 of 0.69 and 0.92 for Luchu and Yuanlin soils, respectively, was found using the first-order kinetics law. In leaching experiment, carbofuran exhibited easier movement in Luchu than in Yuanlin soil.

  3. Compiling a data base of groundwater levels in German organic soils

    NASA Astrophysics Data System (ADS)

    Tiemeyer, Bärbel; Bechtold, Michel; Belting, Susanne; Laggner, Andreas; Freibauer, Annette

    2013-04-01

    Although covering only around 5 % of the country, drained peatlands are the largest single source of greenhouse gas (GHG) emissions besides the energy sector in Germany. GHG emissions from peatlands are very sensitive to changes in the groundwater level, which poses an enormous challenge when upscaling hydrological and gas exchange models to the national scale. However, to compile an improved inventory of GHG emissions from organic soils and to assess the effects of re-wetting measures, upscaling methods for the groundwater level need to be developed. Moreover, to develop robust vegetation indicators for GHG emissions, groundwater level parameters of relevant vegetation types need to be known. Here, we present a unique dataset on groundwater levels in organic soils. Groundwater level data from research and re-wetting projects was collected, checked and harmonised. Presently, our data base contains time series from more than 60 peatlands and 1100 dipwells, resulting in around 8000 annual data sets. Per area, 3 to 91 dipwells have been installed, while the lengths of the time series span from one to 21 years, facilitating the analysis of temporal trends. As groundwater data is generally mainly collected within the frame of re-wetting projects, the majority of the data is from such areas. Thus, the main land use categories for peatlands in Germany, grassland and arable land, are still underrepresented in the data set. At the moment, for all dipwells, land use as taken from official land use statistics (ATKIS), soil type according to the geological map GUEK200 (1:200.000), climatic parameters and the protection status (e.g. nature reserves and NATURA2000) are known. If available, the data base contains more precise site information on vegetation, restoration methods and soils. This dataset will used for both the regionalisation of the groundwater table and and an improvement of vegetation-based proxies for GHG emissions.

  4. Soil, Groundwater, Surface Water, and Sediments of Kennedy Space Center, Florida: Background Chemical and Physical Characteristics

    NASA Technical Reports Server (NTRS)

    Shmalzer, Paul A.; Hensley, Melissa A.; Mota, Mario; Hall, Carlton R.; Dunlevy, Colleen A.

    2000-01-01

    This study documented background chemical composition of soils, groundwater, surface; water, and sediments of Kennedy Space Center. Two hundred soil samples were collected, 20 each in 10 soil classes. Fifty-one groundwater wells were installed in 4 subaquifers of the Surficial Aquifer and sampled; there were 24 shallow, 16 intermediate, and 11 deep wells. Forty surface water and sediment samples were collected in major watershed basins. All samples were away from sites of known contamination. Samples were analyzed for organochlorine pesticides, aroclors, chlorinated herbicides, polycyclic aromatic hydrocarbons (PAH), total metals, and other parameters. All aroclors (6) were below detection in all media. Some organochlorine pesticides were detected at very low frequencies in soil, sediment, and surface water. Chlorinated herbicides were detected at very low frequencies in soil and sediments. PAH occurred in low frequencies in soiL, shallow groundwater, surface water, and sediments. Concentrations of some metals differed among soil classes, with subaquifers and depths, and among watershed basins for surface water but not sediments. Most of the variation in metal concentrations was natural, but agriculture had increased Cr, Cu, Mn, and Zn.

  5. Relations of As concentrations among groundwater, soil, and bedrock in Chungnam, Korea: implications for As mobilization in groundwater according to the As-hosting mineral change.

    PubMed

    Kim, Kangjoo; Kim, Seok-Hwi; Jeong, Gi Young; Kim, Rak-Hyeon

    2012-01-15

    Arsenic (As) concentrations and As-bearing minerals in bedrock and soil, and their relations with groundwater concentrations were investigated in a small agricultural area of Korea. The As concentration of the bedrock shows a wide variation (<0.5-3990 mg/kg) and is well correlated with that in the contacting groundwaters (23-178 μg/L). Soils, the weathering product of bedrock, show the lower and more dispersed As concentrations (8.8-387 mg/kg) than the bedrock. But the soil As concentrations are very high relative to those reported from other areas. The As concentrations in the shallow groundwaters are comparatively low (<20 μg/L) and are independent of the soil concentration. Arsenopyrite is the major As-bearing mineral in the bedrock and its oxidation controls the As levels in deep groundwater. In contrast, As mostly resides in soil as Fe-(hydr)oxide-bound forms. Due to low pH and oxidizing redox condition, the release of As from Fe-(hydr)oxides is largely suppressed, and the shallow groundwater shows low As concentrations generally satisfying the drinking water limit. However, it is suggested that the disturbance of soil geochemical conditions by land use changes would cause a serious As contamination of the shallow groundwaters.

  6. Evaluation of air sparging and vadose zone aeration for remediation of iron and manganese-impacted groundwater at a closed municipal landfill.

    PubMed

    Pleasant, Saraya; O'Donnell, Amanda; Powell, Jon; Jain, Pradeep; Townsend, Timothy

    2014-07-01

    High concentrations of iron (Fe(II)) and manganese (Mn(II)) reductively dissolved from soil minerals have been detected in groundwater monitoring wells near many municipal solid waste landfills. Air sparging and vadose zone aeration (VZA) were evaluated as remedial approaches at a closed, unlined municipal solid waste landfill in Florida, USA. The goal of aeration was to oxidize Fe and Mn to their respective immobile forms. VZA and shallow air sparging using a partially submerged well screen were employed with limited success (Phase 1); decreases in dissolved iron were observed in three of nine monitoring wells during shallow air sparging and in two of 17 wells at VZA locations. During Phase 2, where deeper air sparging was employed, dissolved iron levels decreased in a significantly greater number of monitoring wells surrounding injection points, however no radial pattern was observed. Additionally, in wells affected positively by air sparging (mean total iron (FeTOT) <4.2mg/L, after commencement of air sparging), rising manganese concentrations were observed, indicating that the redox potential of the groundwater moved from an iron-reducing to a manganese-reducing environment. The mean FeTOT concentration observed in affected monitoring wells throughout the study was 1.40 mg/L compared to a background of 15.38 mg/L, while the mean Mn concentration was 0.60 mg/L compared to a background level of 0.27 mg/L. Reference wells located beyond the influence of air sparging areas showed little variation in FeTOT and Mn, indicating the observed effects were the result of air injection activities at study locations and not a natural phenomenon. Air sparging was found effective in intercepting plumes of dissolved Fe surrounding municipal landfills, but the effect on dissolved Mn was contrary to the desired outcome of decreased Mn groundwater concentrations.

  7. A New Screening Method for Methane in Soil Gas Using Existing Groundwater Monitoring Wells

    EPA Science Inventory

    Methane in soil gas may have undesirable consequences. The soil gas may be able to form a flammable mixture with air and present an explosion hazard. Aerobic biodegradation of the methane in soil gas may consume oxygen that would otherwise be available for biodegradation of gasol...

  8. Risk-based assessment of soil and groundwater quality in The Netherlands: standards and remediation urgency.

    PubMed

    Swartjes, F A

    1999-12-01

    To assess soil and groundwater quality two generic (i.e. multifunctional) risk-based standards, Target and Intervention Value, have been developed, in the framework of the Dutch Soil Protection Act. These standards allow soil and groundwater to be classified as clean, slightly contaminated or seriously contaminated. The Target Value is based on potential risks to ecosystems, while the Intervention Value is based on potential risks to humans and ecosystems. In the case of serious soil contamination the site has, in principle, to be remediated, making it necessary to determine the remediation urgency on the basis of actual (i.e. site-specific) risks to humans and ecosystems and, besides, actual risks due to contaminant migration.

  9. Leaching behaviour of pharmaceuticals in soil-testing-systems: a part of an environmental risk assessment for groundwater protection.

    PubMed

    Oppel, J; Broll, G; Löffler, D; Meller, M; Römbke, J; Ternes, Th

    2004-07-26

    The leaching behaviour of six selected pharmaceuticals was tested in different soils. Leaching experiments are a part of environmental risk assessment to estimate the distribution and fate of these pharmaceuticals in the environment. Based on the results of this assessment their mobility in soil and their potential to contaminate groundwater was evaluated. When assessing the leaching behaviour of these compounds, the influence of the properties (e.g. grain size distribution, pH, Corg) of different soils has to be taken into account. The test results indicated that the leaching potential found could be rated as low for diazepam, ibuprofen, ivermectin and carbamazepine. Therefore, contamination of the groundwater with these substances seems to be unlikely if the groundwater level is covered with sufficient layers of the soils investigated. Clofibric acid and iopromide were very mobile under the experimental conditions and thus, groundwater contamination would be possible if the soil is exposed to these pharmaceuticals, i.e. wastewater irrigation. These results are more or less in agreement with groundwater monitoring data found in the literature for ibuprofen and diazepam which were in general not present in groundwater, while clofibric acid and iopromide were frequently detected. However, a discrepancy was found for carbamazepine, since it occurs very often in groundwater. This discrepancy might be explained by the fact that the leaching tests were performed with soil, whereas in reality the groundwater contamination occurs mainly over river sediments and sub soil from receiving waters.

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

    PubMed

    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.

  11. Impact of the December 2004 tsunami on soil, groundwater and vegetation in the Nagapattinam District, India.

    PubMed

    Kume, Takashi; Umetsu, Chieko; Palanisami, K

    2009-07-01

    The tsunami of 26 December 2004 struck the Nagapattinam District, Tamil Nadu, India. Sea water inundation from the tsunami caused salinization problems for soil and groundwater in coastal areas of the district, and also induced salt injuries in crops. To document the recovery of the agricultural environment from the tsunami, we conducted observations of the soil, groundwater, and vegetation. Soil electrical conductivity increased sharply after the tsunami, but returned to pre-tsunami levels the following year. Groundwater salinity returned to pre-tsunami levels by 2006. These rapid rates of recovery were due to the monsoon rainfall leaching salt from the highly permeable soils in the area. MODIS NDVI values measured before and after the tsunami showed that vegetation damaged by the tsunami recovered to its pre-tsunami state by the next rice cropping season, called samba, which starts from August to February. From these results, we conclude that the agricultural environment of the district has now fully recovered from the tsunami. Based on the results, we have also identified important management implications for soil, groundwater, and vegetation as follows: 1) due to the heavy monsoon rainfall and the high permeability of soils in this region, anthropogenic inputs like fertilizers should be applied carefully to minimize pollution, and the use of green manure is recommended; 2) areas that were contaminated by sea water extended up to 1000 m from the sea shore and over pumping of groundwater should be carefully avoided to prevent inducing sea water intrusion; and 3) data from a moderate resolution sensor of 250 m, such as MODIS, can be applied to impact assessment in widespread paddy field areas like the Nagapattinam District.

  12. Air distribution and size changes in the remediated zone after air sparging for soil particle movement.

    PubMed

    Tsai, Yih-Jin

    2008-10-30

    In an unconsolidated porous medium, soil particles can be mobilized by physical perturbation. In model systems of fluids flowing over spherical particles attached to flat surfaces, the hydrodynamic shear force depends on the fluid viscosity, particle radius, and flow velocity. Soil particles can be reasonably expected to be transported by flowing water during air sparging when the particle-size distribution does not fit the densest possible particle arrangement. If soil particles are transported during air sparging, then the distribution of the porosity and reservoir permeability will change. The remediated zone changes because of the changes in soil characteristics. This study applied some mathematical models to elucidate the mobilization process of soil particles during in situ air sparging. The changes in the characteristics of the soil and the swept volume of injected air during air sparging were also investigated. The results demonstrated that particle movement reduced the radius of influence (ROI) and the swept volume of injected air. In this case study, the maximum reducing rates in ROI and the swept volume were 24% and 26% for the zone where the gas saturation exceeded 10%.

  13. Groundwater recharge on east side soils of the Salinas Valley

    Technology Transfer Automated Retrieval System (TEKTRAN)

    After four years of drought, groundwater levels in the Salinas Valley are at historically low levels which threaten to adversely affect farming in the Salinas Valley. Given the prospect of a strong El Niño this coming winter, it seems prudent to plan to capture as much of the rainfall as possible to...

  14. Crossflow air stripping and catalytic oxidation of chlorinated hydrocarbons from groundwater

    SciTech Connect

    Gavaskar, A.R.; Kim, B.C.; Rosansky, S.H.; Ong, S.K.; Marchand, E.G.

    1995-02-01

    This paper describes air stripping of chlorinated hydrocarbon contaminants from groundwater in a crossflow air stripping tower and destruction of the organic compounds by catalytic oxidation. Crossflow stripping has an advantage over conventional countercurrent stripping. In typical stripping operations, the mass transfer coefficient is insensitive to the velocity of the gas stream. The crossflow stripping tower is a geometry that increases the cross section of gas flow while making minimal disturbances to the liquid flow, allowing high gas-liquid ratios without flooding. By increasing the flow cross section for the gas stream, pressure drop (and thus fan power) can be reduced significantly. A field demonstration of the crossflow column was performed at a contaminated groundwater site. The groundwater was pumped out and sent to two 17-ft-high (5.2-m) towers in a parallel arrangement. One tower was a crossflow air stripper and the other a conventional countercurrent design. The performance of the two was compared. The key organic species targeted was dichloroethane, which has a low Henry`s law constant. Three different baffle configurations were tested in the crossflow tower. The results of this demonstration were used to develop design criteria for crossflow air strippers to be used for destruction of halogenated hydrocarbons. 4 refs., 15 figs., 2 tabs.

  15. In situ treatment of arsenic-contaminated groundwater by air sparging.

    PubMed

    Brunsting, Joseph H; McBean, Edward A

    2014-04-01

    Arsenic contamination of groundwater is a major problem in some areas of the world, particularly in West Bengal (India) and Bangladesh where it is caused by reducing conditions in the aquifer. In situ treatment, if it can be proven as operationally feasible, has the potential to capture some advantages over other treatment methods by being fairly simple, not using chemicals, and not necessitating disposal of arsenic-rich wastes. In this study, the potential for in situ treatment by injection of compressed air directly into the aquifer (i.e. air sparging) is assessed. An experimental apparatus was constructed to simulate conditions of arsenic-rich groundwater under anaerobic conditions, and in situ treatment by air sparging was employed. Arsenic (up to 200 μg/L) was removed to a maximum of 79% (at a local point in the apparatus) using a solution with dissolved iron and arsenic only. A static "jar" test revealed arsenic removal by co-precipitation with iron at a molar ratio of approximately 2 (iron/arsenic). This is encouraging since groundwater with relatively high amounts of dissolved iron (as compared to arsenic) therefore has a large theoretical treatment capacity for arsenic. Iron oxidation was significantly retarded at pH values below neutral. In terms of operation, analysis of experimental results shows that periodic air sparging may be feasible.

  16. Immobilization of selenite in soil and groundwater using stabilized Fe-Mn binary oxide nanoparticles.

    PubMed

    Xie, Wenbo; Liang, Qiqi; Qian, Tianwei; Zhao, Dongye

    2015-03-01

    Stabilized Fe-Mn binary oxide nanoparticles were synthesized and tested for removal and in-situ immobilization of Se(IV) in groundwater and soil. A water-soluble starch or food-grade carboxymethyl cellulose (CMC) was used as a stabilizer to facilitate in-situ delivery of the particles into contaminated soil. While bare and stabilized nanoparticles showed rapid sorption kinetics, starch-stabilized Fe-Mn offered the greatest capacity for Se(IV). The Langmuir maximum capacity was determined to be 109 and 95 mg-Se/g-Fe for starch- and CMC-stabilized nanoparticles, respectively, and the high Se(IV) uptake was observed over the typical groundwater pH range of 5-8. Column breakthrough tests indicated that the stabilized nanoparticles were deliverable in a model sandy soil while non-stabilized particles were not. When a Se(IV)-spiked soil was treated in situ with the nanoparticles, >90% water leachable Se(IV) was transferred to the nanoparticle phase, and thereby immobilized as the particles were retained in the downstream soil matrix. The nanoparticle amendment reduced the TCLP (toxicity characteristic leaching procedure) leachability and the California WET (waste extraction test) leachability of Se(IV) by 76% and 71%, respectively. The technology holds the potential to fill a major technology gap in remediation of metals-contaminated soil and groundwater.

  17. Chemical substance transport in soils and its effect on groundwater quality.

    PubMed

    Khublarian, M G

    1989-11-01

    The problems of chemical substance applications in different spheres of industry and agriculture and their effects on groundwater quality and human health are described. Sources of groundwater contamination from industrial and municipal wastes, agricultural pollutants, etc., are listed. The experience in the application of chemical fertilizers and pesticides in the USSR is described. A brief estimation of groundwater salinity is given for various regions of the USSR where irrigation is practiced, as well as the experience in environmental protection. Special attention is given to methods of simulating water seepage and chemical substance transport in soils. Boundary problems for free-surface seepage and dissolved solids transport in porous media are stated, and methods of solution are described in the example of the hydrodynamic theory of seepage and dispersion. Some results of calculations with this method are presented. The influence of groundwater quality on the morbidity of the population is given and the main diseases and associated medical problems are listed.

  18. Simulation of regional-scale groundwater flow in the Azul River basin, Buenos Aires Province, Argentina

    NASA Astrophysics Data System (ADS)

    Varni, Marcelo R.; Usunoff, Eduardo J.

    A three-dimensional modular model (MODFLOW) was used to simulate groundwater flow in the Azul River basin, Buenos Aires Province, Argentina, in order to assess the correctness of the conceptual model of the hydrogeological system. Simulated heads satisfactorily match observed heads in the regional water-table aquifer. Model results indicate that: (1) groundwater recharge is not uniform throughout the region but is best represented by three recharge rates, decreasing downgradient, similar to the distribution of soils and geomorphological characteristics; and (2) evapotranspiration rates are larger than previous estimates, which were made by using the Thornthwaite-Mather method. Evapotranspiration rates estimated by MODFLOW agree with results of independent studies of the region. Model results closely match historical surface-flow records, thereby suggesting that the model description of the aquifer-river relationship is correct. Résumé Un modèle modulaire tridimensionnel (MODFLOW) a été utilisé pour simuler les écoulements souterrains dans le bassin de la rivière Azul (Province de Buenos Aires, Argentine), dans le but d'évaluer la justesse du modèle conceptuel du système hydrogéologique. La piézométrie simulée s'ajuste de façon satisfaisante à celle observée pour l'ensemble de la nappe. Les résultats du modèle indiquent que: (1) la recharge de la nappe n'est pas uniforme sur toute la région, mais qu'elle est mieux approchée par trois valeurs différentes, décroissant vers l'aval-gradient, en suivant la même distribution que les sols et les caractéristiques géomorphologiques et (2) l'évapotranspiration est nettement plus importante que prévu initialement à partir de la méthode de Thornthwaite-Mather. Les valeurs d'évapotranspiration fournies par MODFLOW concordent bien avec les résultats d'autres études portant sur la région. Les résultats du modèle reproduisent convenablement les chroniques de débit des écoulements de surface

  19. 40 CFR 280.65 - Investigations for soil and ground-water cleanup.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-water cleanup. 280.65 Section 280.65 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Containing Petroleum or Hazardous Substances § 280.65 Investigations for soil and ground-water cleanup. (a... presence and concentrations of dissolved product contamination in the ground water, owners and...

  20. Groundwater pollution potential and greenhouse gas emission from soils amended with different swine biochars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although there exist numerous research studies in the literature on greenhouse gas emission and groundwater pollution potentials of soils amended with plant-based biochar made from traditional dry pyrolysis (hereafter referred as pyrochar), a very few such studies exist for hydrochar made from hydro...

  1. PHYTOREMEDIATION: USING PLANTS TO CLEAN UP CONTAMINATED SOIL, GROUNDWATER, AND WASTEWATER

    EPA Science Inventory

    Phytoremediation is an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost. The cleanup technology is defined as the use of green plants to remove, contain, or render harmless such environmental contaminants as heavy ...

  2. IN SITU TREATMENT OF SOIL AND GROUNDWATER CONTAMINATED WITH CHROMIUM - TECHNICAL RESOURCE GUIDE

    EPA Science Inventory

    New information and treatment approaches have been developed for chromium-contaminated soil and groundwater treatment. The prupose of this report is to bring together the most current information pertaining to the science of chromium contamination and the insitu treatment and co...

  3. IN-SITU REDUCTION OF CHROMIUM-CONTAMINATED GROUNDWATER, SOILS, AND SEDIMENTS BY SODIUM DITHIONITE

    EPA Science Inventory

    Laboratory studies were conducted to characterize the extent of chromium contamination in the groundwater and underlying soils and sediments of a chrome-plating shop at the USCG Support Center near Elizabeth City, NC. Most of the mobile Cr(VI) is present in the capillary zone ...

  4. On the potential of biological treatment for arsenic contaminated soils and groundwater.

    PubMed

    Wang, Suiling; Zhao, Xiangyu

    2009-06-01

    Bioremediation of arsenic contaminated soils and groundwater shows a great potential for future development due to its environmental compatibility and possible cost-effectiveness. It relies on microbial activity to remove, mobilize, and contain arsenic through sorption, biomethylation-demethylation, complexation, coprecipitation, and oxidation-reduction processes. This paper gives an evaluation on the feasibility of using biological methods for the remediation of arsenic contaminated soils and groundwater. Ex-situ bioleaching can effectively remove bulk arsenic from contaminated soils. Biostimulation such as addition of carbon sources and mineral nutrients can be applied to promote the leaching rate. Biosorption can be used either ex-situ or in-situ to remove arsenic from groundwater by sorption to biomass and/or coprecipitation with biogenic solids or sulfides. Introduction of proper biosorbents or microorganisms to produce active biosorbents in-situ is the key to the success of this method. Phytoremediation depends on arsenic-hyperaccumulating plants to remove arsenic from soils and shallow groundwater by translocating it into plant tissues. Engineering genetic strategies can be employed to increase the arsenic-hyperaccumulating capacity of the plants. Biovolatilization may be developed potentially as an ex-situ treatment technology. Further efforts are needed to focus on increasing the volatilization rate and the post-treatment of volatilization products.

  5. Hydrogeology, simulated ground-water flow, and ground-water quality, Wright-Patterson Air Force Base, Ohio

    USGS Publications Warehouse

    Dumouchelle, D.H.; Schalk, C.W.; Rowe, G.L.; De Roche, J.T.

    1993-01-01

    Ground water is the primary source of water in the Wright-Patterson Air Force Base area. The aquifer consists of glacial sands and gravels that fill a buried bedrock-valley system. Consolidated rocks in the area consist of poorly permeable Ordovician shale of the Richmondian stage, in the upland areas, the Brassfield Limestone of Silurian age. The valleys are filled with glacial sediments of Wisconsinan age consisting of clay-rich tills and coarse-grained outwash deposits. Estimates of hydraulic conductivity of the shales based on results of displacement/recovery tests range from 0.0016 to 12 feet per day; estimates for the glacial sediments range from less than 1 foot per day to more than 1,000 feet per day. Ground water flow from the uplands towards the valleys and the major rivers in the region, the Great Miami and the Mad Rivers. Hydraulic-head data indicate that ground water flows between the bedrock and unconsolidated deposits. Data from a gain/loss study of the Mad River System and hydrographs from nearby wells reveal that the reach of the river next to Wright-Patterson Air Force Base is a ground-water discharge area. A steady-state, three-dimensional ground-water-flow model was developed to simulate ground-water flow in the region. The model contains three layers and encompasses about 100 square miles centered on Wright-Patterson Air Force Base. Ground water enters the modeled area primarily by river leakage and underflow at the model boundary. Ground water exits the modeled area primarily by flow through the valleys at the model boundaries and through production wells. A model sensitivity analysis involving systematic changes in values of hydrologic parameters in the model indicates that the model is most sensitive to decreases in riverbed conductance and vertical conductance between the upper two layers. The analysis also indicates that the contribution of water to the buried-valley aquifer from the bedrock that forms the valley walls is about 2 to 4

  6. Radon tracing of groundwater discharge into an Australian estuary surrounded by coastal acid sulphate soils

    NASA Astrophysics Data System (ADS)

    Santos, Isaac R.; Eyre, Bradley D.

    2011-01-01

    SummaryWidespread sulphidic deposits have accumulated in tropical coastal floodplains throughout the world. Sulphidic soils oxidize when floodplains are drained for urban and agricultural development. As a result, large amounts of sulphuric acid may be released to nearby waterways. Macropores may create excellent conditions for groundwater flow in coastal acid sulphate soils (CASS). An automated radon ( 222Rn) measurement system was used to quantify groundwater inputs into a tidally-dominated estuary that is known to be influenced by acid discharges from CASS (Richmond River Estuary, Australia). A high resolution radon survey along a 120-km long segment of the tidal river identified two areas of preferential groundwater inputs. Intensive time series measurements in one of those areas (the Tuckean Broadwater) demonstrated that groundwater inputs are highly variable over hourly and seasonal time scales and inversely related to surface water pH. Elevated radon concentrations (up to 12 dpm/L) and low pH (as low as 3.3) were observed in surface waters at low tide a few weeks after a large rain event. These results demonstrate that acidic waters are entering the estuary via tidally-modulated groundwater flow pathways. Groundwater discharge rates into drains in the Tuckean Swamp were estimated from a dual-assumption radon mass balance to be 0.09-0.16 and 0.56-0.89 m 3 s -1 during the dry and wet season, respectively (or 6-10 and 37-59 cm/day if the area is taken into account). While surface runoff increased only 2-fold in the wet season relative to the dry season, groundwater discharge rates increased ˜6-fold. Since groundwater can be a major driver of surface water quality, radon can be useful in CASS monitoring and management efforts.

  7. Geochemical study of groundwater at Sandia National Laboratories/New Mexico and Kirtland Air Force Base

    SciTech Connect

    1995-10-01

    The U.S. Department of Energy (DOE) Grand Junction Projects Office (GJPO) and its contractor, Rust Geotech, support the Kirtland Area Office by assisting Sandia National Laboratories/New Mexico (Sandia/NM) with remedial action, remedial design, and technical support of its Environmental Restoration Program. To aid in determining groundwater origins and flow paths, the GJPO was tasked to provide interpretation of groundwater geochemical data. The purpose of this investigation was to describe and analyze the groundwater geochemistry of the Sandia/NM Kirtland Air Force Base (KAFB). Interpretations of groundwater origins are made by using these data and the results of {open_quotes}mass balance{close_quotes} and {open_quotes}reaction path{close_quote} modeling. Additional maps and plots were compiled to more fully comprehend the geochemical distributions. A more complete set of these data representations are provided in the appendices. Previous interpretations of groundwater-flow paths that were based on well-head, geologic, and geochemical data are presented in various reports and were used as the basis for developing the models presented in this investigation.

  8. Relationships between groundwater, surface water, and soil salinity in Polder 32, Southwest Bangladesh

    NASA Astrophysics Data System (ADS)

    Fry, D. C.; Ayers, J. C.

    2014-12-01

    In the coastal areas of Southwest Bangladesh polders are surrounded by tidal channels filled with brackish water. In the wet season, farmers create openings in the embankments to irrigate rice paddies. In the dry season, farmers do the same to create saline shrimp ponds. Residents on Polder 32, located within the Ganges-Brahmaputra-Meghna delta system, practice these seasonal farming techniques. Soils in the area are entisols, being sediment recently deposited, and contain mostly silt-sized particles. Brackish water in brine shrimp ponds may deposit salt in the soil, causing soil salinization. However, saline connate groundwater could also be contributing to soil salinization. Groundwater, surface water (fresh water pond, rice paddy and tidal channel water) and soil samples have been analyzed via inductively coupled plasma optical emission spectroscopy, inductively coupled plasma mass spectroscopy and ion chromatography in an attempt to correlate salinity measurements with each other in order to determine major sources of soil salinity. Multiple parameters, including distances of samples from tidal channels, inland streams, shrimp ponds and tube wells were measured to see if spatial correlations exist. Similarly, values from wet and dry seasons were compared to quantify temporal variations. Salt content in many soil samples were found to be high enough to significantly decrease rice yields. Continued soil salinization can decrease these yields even more, leading to farmers not producing enough food to sustain their families.

  9. Reactive transport controls on sandy acid sulfate soils and impacts on shallow groundwater quality

    NASA Astrophysics Data System (ADS)

    Salmon, S. Ursula; Rate, Andrew W.; Rengel, Zed; Appleyard, Steven; Prommer, Henning; Hinz, Christoph

    2014-06-01

    Disturbance or drainage of potential acid sulfate soils (PASS) can result in the release of acidity and degradation of infrastructure, water resources, and the environment. Soil processes affecting shallow groundwater quality have been investigated using a numerical code that integrates (bio)geochemical processes with water, solute, and gas transport. The patterns of severe and persistent acidification (pH < 4) in the sandy, carbonate-depleted podzols of a coastal plain could be reproduced without calibration, based on oxidation of microcrystalline pyrite after groundwater level decrease and/or residual groundwater acidity, due to slow vertical solute transport rates. The rate of acidification was limited by gas phase diffusion of oxygen and hence was sensitive to soil water retention properties and in some cases also to oxygen consumption by organic matter mineralization. Despite diffusion limitation, the rate of oxidation in sandy soils was rapid once pyrite-bearing horizons were exposed, even to a depth of 7.5 m. Groundwater level movement was thus identified as an important control on acidification, as well as the initial pyrite content. Increase in the rate of Fe(II) oxidation lead to slightly lower pH and greater accumulation of Fe(III) phases, but had little effect on the overall amount of pyrite oxidized. Aluminosilicate (kaolinite) dissolution had a small pH-buffering effect but lead to the release of Al and associated acidity. Simulated dewatering scenarios highlighted the potential of the model for risk assessment of (bio)geochemical impacts on soil and groundwater over a range of temporal and spatial scales.

  10. Effects of changing channel morphology on vegetation, groundwater, and soil moisture regimes in groundwater-dependent ecosystems

    NASA Astrophysics Data System (ADS)

    Loheide, Steven P.; Booth, Eric G.

    2011-03-01

    Channel incision, channel widening, and excessive floodplain sedimentation are major causes of riparian ecosystem degradation across the country. Although the causes and consequences of these processes vary significantly, the resulting morphology in all cases results in a lower stream stage relative to the floodplain surface for any given discharge. This change in channel morphology alters surface water-groundwater interactions between the stream and the riparian aquifer and affects the soil moisture and groundwater regimes differentially across the floodplain. The distribution of vegetation is altered as the hydrologic regime shifts between the hydrologic niches of potential species. We simulate the hydroecologic response of a groundwater-dependent ecosystem on the floodplain of an archetypical watershed under three scenarios representing changes in channel morphology: a base case, a widened channel case, and an incised channel case. Stochastically-driven synthetic rainfall records are used to drive a rainfall-runoff model of the archetype watershed. The resulting hydrograph is transformed to stage via Manning's equation for the three channel morphologies considered. This stage record is used as a boundary condition for a finite-element model simulating 2-dimensional, variably-saturated groundwater flow in the riparian aquifer. The model predicts soil moisture and groundwater regimes lateral to the channel. The 7-day moving average high water level is determined for ten growing seasons and used to predict the distribution of three species across the floodplain. Plant frequency is predicted for Carex emoryi (an obligate wetland species), Carex crawei (facultative wetland species), and Carex duriuscula (a facultative upland species) for each of the channel morphologies considered. The frequency is predicted using existing nonlinear parametric species response curves determined empirically for these species using direct gradient analysis. Results show the sensitivity

  11. Rapid assessment of soil and groundwater tritium by vegetation sampling

    SciTech Connect

    Murphy, C.E. Jr.

    1995-09-01

    A rapid and relatively inexpensive technique for defining the extent of groundwater contamination by tritium has been investigated. The technique uses existing vegetation to sample the groundwater. Water taken up by deep rooted trees is collected by enclosing tree branches in clear plastic bags. Water evaporated from the leaves condenses on the inner surface of the bag. The water is removed from the bag with a syringe. The bags can be sampled many times. Tritium in the water is detected by liquid scintillation counting. The water collected in the bags has no color and counts as well as distilled water reference samples. The technique was used in an area of known tritium contamination and proved to be useful in defining the extent of tritium contamination.

  12. PHYTOREMEDIATION OF GROUNDWATER AT AIR FORCE PLANT 4, CARSWELL, TEXAS - INNOVATIVE TECHNOLOGY EVALUATION REPORT (CD-ROM)

    EPA Science Inventory

    Over 600 Cottonwood trees were planted over a shallow groundwater plume in an attempt to detoxify the tricWoroethylene (TCE) in a groundwater plume at a former Air Force facility. Two planting techniques were used: rooted stock about two years old, and 18 inch cuttings were insta...

  13. Air sparging in low permeability soils

    SciTech Connect

    Marley, M.C.

    1996-08-01

    Sparging technology is rapidly growing as a preferred, low cost remediation technique of choice at sites across the United States. The technology is considered to be commercially available and relatively mature. However, the maturity is based on the number of applications of the technology as opposed to the degree of understanding of the mechanisms governing the sparging process. Few well documented case studies exist on the long term operation of the technology. Sparging has generally been applied using modified monitoring well designs in uniform, coarse grained soils. The applicability of sparging for the remediation of DNAPLs in low permeability media has not been significantly explored. Models for projecting the performance of sparging systems in either soils condition are generally simplistic but can be used to provide general insight into the effects of significant changes in soil and fluid properties. The most promising sparging approaches for the remediation of DNAPLs in low permeability media are variations or enhancements to the core technology. Recirculatory sparging systems, sparging/biosparging trenches or curtains and heating or induced fracturing techniques appear to be the most promising technology variants for this type of soil. 21 refs., 9 figs.

  14. Harmonization of environmental quality objectives for air, water and soil

    SciTech Connect

    Plassche, E.J. van de

    1994-12-31

    Environmental quality objectives (EQO) are often derived for single compartments only. However, concentrations at or below EQO level for one compartment may lead to exceeding of the EQO in another compartment due to intermedia transport of the chemical. Hence, achieving concentrations lower than the EQO in e.g. air does not necessarily mean that a ``safe`` concentration in soil can be maintained because of deposition from air to soil. This means that EQOs for air, water and soil must be harmonized in such a way that they meet a coherence criterion. This criterion implies that a EQO for one compartment has to be set at a level that full protection to organisms living in other compartments is ensured. In The Netherlands a project has been started to derive harmonized EQOs for a large number of chemicals. First, EQ0s are derived for all compartments based on ecotoxicological data for single species applying extrapolation methods. Secondly, these independently derived EQOs are harmonized. For harmonization of EQOs for water, sediment and soil the equilibrium partitioning method is used. For harmonization of EQOs for water and soil with the E00s for air a procedure is used applying computed steady state concentration ratios rather than equilibrium partitioning. The model SimpleBox is used for these computations. Some results of the project mentioned above will be presented. Attention will be paid to the derivation of independent EQ0s as well as the harmonization procedures applied.

  15. Distribution of volatile organic compounds (VOCs) in surface water, soil, and groundwater within a chemical industry park in Eastern China.

    PubMed

    Liu, Benhua; Chen, Liang; Huang, Linxian; Wang, Yongseng; Li, Yuehua

    2015-01-01

    This paper focuses on the distribution of volatile organic compounds (VOCs) in the surface water, soil, and groundwater within a chemical industry park in Eastern China. At least one VOC was detected in each of the 20 sampling sites, and the maximum number of VOCs detected in the surface water, groundwater, and soil were 13, 16, and 14, respectively. Two of the 10 VOCs with elevated concentrations detected in surface water, groundwater, and soil were chloroform and 1,2-dichloroethane. The characteristics of VOCs, which include volatility, boiling point, and solubility, could significantly affect their distribution in surface water, soil, and groundwater. However, due to the direct discharging of chemical industry wastewater into surface water, higher concentrations of VOCs (except chloroform) were detected in surface water than in soil and groundwater. Fortunately, the higher volatility of VOCs prevents the VOCs from impacting groundwater, which helps to maintain a lower concentration of VOCs in the groundwater than in both surface water and soil. This is because pollutants with relatively higher boiling points and lower solubilities have higher detection frequencies in soil, and contaminants with relatively lower boiling points and higher solubilities have higher detection frequencies in water, notably in surface water. PMID:25633950

  16. Distribution of volatile organic compounds (VOCs) in surface water, soil, and groundwater within a chemical industry park in Eastern China.

    PubMed

    Liu, Benhua; Chen, Liang; Huang, Linxian; Wang, Yongseng; Li, Yuehua

    2015-01-01

    This paper focuses on the distribution of volatile organic compounds (VOCs) in the surface water, soil, and groundwater within a chemical industry park in Eastern China. At least one VOC was detected in each of the 20 sampling sites, and the maximum number of VOCs detected in the surface water, groundwater, and soil were 13, 16, and 14, respectively. Two of the 10 VOCs with elevated concentrations detected in surface water, groundwater, and soil were chloroform and 1,2-dichloroethane. The characteristics of VOCs, which include volatility, boiling point, and solubility, could significantly affect their distribution in surface water, soil, and groundwater. However, due to the direct discharging of chemical industry wastewater into surface water, higher concentrations of VOCs (except chloroform) were detected in surface water than in soil and groundwater. Fortunately, the higher volatility of VOCs prevents the VOCs from impacting groundwater, which helps to maintain a lower concentration of VOCs in the groundwater than in both surface water and soil. This is because pollutants with relatively higher boiling points and lower solubilities have higher detection frequencies in soil, and contaminants with relatively lower boiling points and higher solubilities have higher detection frequencies in water, notably in surface water.

  17. Root-soil air gap and resistance to water flow at the soil-root interface of Robinia pseudoacacia.

    PubMed

    Liu, X P; Zhang, W J; Wang, X Y; Cai, Y J; Chang, J G

    2015-12-01

    During periods of water deficit, growing roots may shrink, retaining only partial contact with the soil. In this study, known mathematical models were used to calculate the root-soil air gap and water flow resistance at the soil-root interface, respectively, of Robinia pseudoacacia L. under different water conditions. Using a digital camera, the root-soil air gap of R. pseudoacacia was investigated in a root growth chamber; this root-soil air gap and the model-inferred water flow resistance at the soil-root interface were compared with predictions based on a separate outdoor experiment. The results indicated progressively greater root shrinkage and loss of root-soil contact with decreasing soil water potential. The average widths of the root-soil air gap for R. pseudoacacia in open fields and in the root growth chamber were 0.24 and 0.39 mm, respectively. The resistance to water flow at the soil-root interface in both environments increased with decreasing soil water potential. Stepwise regression analysis demonstrated that soil water potential and soil temperature were the best predictors of variation in the root-soil air gap. A combination of soil water potential, soil temperature, root-air water potential difference and soil-root water potential difference best predicted the resistance to water flow at the soil-root interface.

  18. Soil Surface Carbon Dioxide Fluxes and Carbon Dioxide Concentrations in Soil Air

    NASA Astrophysics Data System (ADS)

    Arkebauer, T. J.; Billesbach, D.

    2006-12-01

    We have been monitoring soil surface CO2 fluxes at three AmeriFlux sites in eastern Nebraska for several years. Recently, we have installed soil CO2 sensors at the rainfed soybean site in order to obtain profiles of CO2 concentrations in soil air (to 0.8 m depth). Supporting data include profiles of soil water content and soil temperature, aboveground biomass, leaf area index and precipitation. Soil surface fluxes had been rather small for much of the 2006 growing season (e.g., midday values of about 5 umol/m2/s) due, in large part, to the very dry conditions in eastern Nebraska and the consequent low soil water contents. However, copious rainfall in August raised soil water contents to field capacity throughout the profile. Soil air CO2 concentrations during this period also increased and reached peaks near 10% (at 0.4 and 0.8 m depth). Through analyses of relationships between surface CO2 flux and profiles of soil parameters we seek to identify biophysical factors responsible for controlling surface fluxes as well as to begin to quantify sources and sinks of CO2 within the soil profile (e.g., plant-related production of CO2 due to root exudation and respiration). The influence of precipitation events on CO2 profiles and fluxes is of particular interest.

  19. Characterization and assessment of contaminated soil and groundwater at an organic chemical plant site in Chongqing, Southwest China.

    PubMed

    Liu, Geng; Niu, Junjie; Zhang, Chao; Guo, Guanlin

    2016-04-01

    Contamination from organic chemical plants can cause serious pollution of soil and groundwater ecosystems. To characterize soil contamination and to evaluate the health risk posed by groundwater at a typical organic chemical plant site in Chongqing, China, 91 soil samples and seven groundwater samples were collected. The concentrations of different contaminants and their three-dimensional distribution were determined based on the 3D-krige method. Groundwater chemistry risk index (Chem RI) and cancer risk were calculated based on TRIAD and RBCA models. The chemistry risk indices of groundwater points SW5, SW18, SW22, SW39, SW52, SW80, and SW82 were 0.4209, 0.9972, 0.9324, 0.9990, 0.9991, 1.0000, and 1.0000, respectively, indicating that the groundwater has poor environmental status. By contrast, the reference Yangtse River water sample showed no pollution with a Chem RI of 0.1301. Benzene and 1,2-dichloroethane were the main contaminants in the groundwater and were responsible for the elevated cancer risk. The cumulative health risk of groundwater points (except SW5 and SW18) were all higher than the acceptable baselines of 10(-6), which indicates that the groundwater poses high cancer risk. Action is urgently required to control and remediate the risk for human health and groundwater ecosystems.

  20. Impact of irrigation with arsenic-rich groundwater on soils and crops.

    PubMed

    Moyano, A; Garcia-Sanchez, A; Mayorga, P; Anawar, H M; Alvarez-Ayuso, E

    2009-03-01

    The study was carried out in an intensively cultivated agricultural area of central Spain where high arsenic (As) concentrations in groundwater were previously reported. The concentrations and distribution of As in soils and crops (wheat, potato, sugar beet and carrot) were determined to know the effect of irrigation with As-rich groundwater in the agricultural fields, and to estimate its impact on the food chain contamination. Irrigation water shows high As concentrations ranging between 38 and 136 microg/l. Total As contents in the studied agricultural soils are higher than 10 mg/kg exceeding the As content in two control areas and the results of this study reflect that irrigation with As-rich groundwater led to the elevated As levels in the agricultural soils. Total As concentration in soils of a sugar beet plot (36 mg/kg) is higher than that found in soils of the less intensively watered field (11 mg/kg), and more than 3.5 times higher than that in the soils of the control area irrigated with uncontaminated water (<10 mg/kg). Water soluble As in soils ranges between 0.03 and 0.9 mg/kg exceeding the limit of 0.04 mg/kg for agricultural use and shows a significant correlation with total As and organic matter (OM) content in soils. Arsenic contents in potato tuber samples are 35 times higher than that measured in potato tuber of uncontaminated control sites (0.03 mg/kg). Elevated As contents (3.9-5.4 mg/kg DW) were also found in root samples of sugar beet. The As contents in vegetable samples are higher than As content (0.1 mg/kg DW) in plants of uncontaminated control areas, and the limits for foodstuffs (0.5-1 mg/kg DW) set by legislation of many countries reflecting the risk of food chain contamination by As in this study area.

  1. Effects of linking a soil-water-balance model with a groundwater-flow model.

    PubMed

    Stanton, Jennifer S; Ryter, Derek W; Peterson, Steven M

    2013-01-01

    A previously published regional groundwater-flow model in north-central Nebraska was sequentially linked with the recently developed soil-water-balance (SWB) model to analyze effects to groundwater-flow model parameters and calibration results. The linked models provided a more detailed spatial and temporal distribution of simulated recharge based on hydrologic processes, improvement of simulated groundwater-level changes and base flows at specific sites in agricultural areas, and a physically based assessment of the relative magnitude of recharge for grassland, nonirrigated cropland, and irrigated cropland areas. Root-mean-squared (RMS) differences between the simulated and estimated or measured target values for the previously published model and linked models were relatively similar and did not improve for all types of calibration targets. However, without any adjustment to the SWB-generated recharge, the RMS difference between simulated and estimated base-flow target values for the groundwater-flow model was slightly smaller than for the previously published model, possibly indicating that the volume of recharge simulated by the SWB code was closer to actual hydrogeologic conditions than the previously published model provided. Groundwater-level and base-flow hydrographs showed that temporal patterns of simulated groundwater levels and base flows were more accurate for the linked models than for the previously published model at several sites, particularly in agricultural areas.

  2. Effects of linking a soil-water-balance model with a groundwater-flow model

    USGS Publications Warehouse

    Stanton, Jennifer S.; Ryter, Derek W.; Peterson, Steven M.

    2013-01-01

    A previously published regional groundwater-flow model in north-central Nebraska was sequentially linked with the recently developed soil-water-balance (SWB) model to analyze effects to groundwater-flow model parameters and calibration results. The linked models provided a more detailed spatial and temporal distribution of simulated recharge based on hydrologic processes, improvement of simulated groundwater-level changes and base flows at specific sites in agricultural areas, and a physically based assessment of the relative magnitude of recharge for grassland, nonirrigated cropland, and irrigated cropland areas. Root-mean-squared (RMS) differences between the simulated and estimated or measured target values for the previously published model and linked models were relatively similar and did not improve for all types of calibration targets. However, without any adjustment to the SWB-generated recharge, the RMS difference between simulated and estimated base-flow target values for the groundwater-flow model was slightly smaller than for the previously published model, possibly indicating that the volume of recharge simulated by the SWB code was closer to actual hydrogeologic conditions than the previously published model provided. Groundwater-level and base-flow hydrographs showed that temporal patterns of simulated groundwater levels and base flows were more accurate for the linked models than for the previously published model at several sites, particularly in agricultural areas.

  3. Air and groundwater pollution in an agricultural region of the Turkish Mediterranean coast.

    PubMed

    Tuncel, Semra G; Oztas, Nur Banu; Erduran, M Soner

    2008-09-01

    Air pollution and groundwater pollution in conjunction with agricultural activity were investigated in Antayla province on the Turkish Mediterranean coast. The air pollution was investigated in terms of gas-phase nitric acid (HNO3), sulfur dioxide (SO2), ammonia (NH3), and particulate matter for a 6-month period in the atmosphere using a "filter pack" system, which was developed and optimized in our laboratory. Ozone was measured by using an automated analyzer. Among all of the gas-phase pollutants, HNO3 had the lowest concentration (0.42 microg x m(-3)) followed by NH3. Agricultural activities seem to be the major source of observed NH3 in the air. The current state of water pollution was investigated in terms of organochlorine and organophosphorus pesticides around the greenhouses, in which mainly tomato, pepper, and eggplant are cultivated. Water samples were collected from 40 points, 28 of which were wells and 12 of which were surface water. The pesticide concentrations in water samples were determined by means of solid-phase extraction (SPE) followed by a gas chromatography (GC)-electron capture detector (ECD)/nitrogen phosphorus detector (NPD) system. In general, surface water samples were more polluted by the pesticides than groundwater samples. The most frequently observed pesticides were chlorpyriphos (57%) and aldrin (79%) in groundwater, and chlorpyriphos (75%), aldrin, and endosulfan sulfate (83%) in surface water samples. The highest concentrations were observed for fenamiphos (394.8 ng/L) and aldrin (68.51 ng/L) in groundwater, and dichlorvos (322.2 ng/L) and endosulfan sulfate (89.5 ng/L) in surface water samples. At least one pesticide had a concentration above the health limit in 38% of all the water samples analyzed.

  4. External exposure to radionuclides in air, water, and soil

    SciTech Connect

    Eckerman, K.F.; Ryman, J.C.

    1996-05-01

    Federal Guidance Report No. 12 tabulates dose coefficients for external exposure to photons and electrons emitted by radionuclides distributed in air, water, and soil. The dose coefficients are intended for use by Federal Agencies in calculating the dose equivalent to organs and tissues of the body.

  5. Exchange of Groundwater and Surface-Water Mediated by Permafrost Response to Seasonal and Long Term Air Temperature Variation

    USGS Publications Warehouse

    Ge, Shemin; McKenzie, Jeffrey; Voss, Clifford; Wu, Qingbai

    2011-01-01

    Permafrost dynamics impact hydrologic cycle processes by promoting or impeding groundwater and surface water exchange. Under seasonal and decadal air temperature variations, permafrost temperature changes control the exchanges between groundwater and surface water. A coupled heat transport and groundwater flow model, SUTRA, was modified to simulate groundwater flow and heat transport in the subsurface containing permafrost. The northern central Tibet Plateau was used as an example of model application. Modeling results show that in a yearly cycle, groundwater flow occurs in the active layer from May to October. Maximum groundwater discharge to the surface lags the maximum subsurface temperature by two months. Under an increasing air temperature scenario of 3?C per 100 years, over the initial 40-year period, the active layer thickness can increase by three-fold. Annual groundwater discharge to the surface can experience a similar three-fold increase in the same period. An implication of these modeling results is that with increased warming there will be more groundwater flow in the active layer and therefore increased groundwater discharge to rivers. However, this finding only holds if sufficient upgradient water is available to replenish the increased discharge. Otherwise, there will be an overall lowering of the water table in the recharge portion of the catchment.

  6. Exchange of groundwater and surface-water mediated by permafrost response to seasonal and long term air temperature variation

    USGS Publications Warehouse

    Ge, S.; McKenzie, J.; Voss, C.; Wu, Q.

    2011-01-01

    Permafrost dynamics impact hydrologic cycle processes by promoting or impeding groundwater and surface water exchange. Under seasonal and decadal air temperature variations, permafrost temperature changes control the exchanges between groundwater and surface water. A coupled heat transport and groundwater flow model, SUTRA, was modified to simulate groundwater flow and heat transport in the subsurface containing permafrost. The northern central Tibet Plateau was used as an example of model application. Modeling results show that in a yearly cycle, groundwater flow occurs in the active layer from May to October. Maximum groundwater discharge to the surface lags the maximum subsurface temperature by two months. Under an increasing air temperature scenario of 3C per 100 years, over the initial 40-year period, the active layer thickness can increase by three-fold. Annual groundwater discharge to the surface can experience a similar three-fold increase in the same period. An implication of these modeling results is that with increased warming there will be more groundwater flow in the active layer and therefore increased groundwater discharge to rivers. However, this finding only holds if sufficient upgradient water is available to replenish the increased discharge. Otherwise, there will be an overall lowering of the water table in the recharge portion of the catchment. Copyright 2011 by the American Geophysical Union.

  7. Natural attenuation processes for remediation of arsenic contaminated soils and groundwater.

    PubMed

    Wang, Suiling; Mulligan, Catherine N

    2006-12-01

    Arsenic (As) contamination presents a hazard in many countries. Natural attenuation (NA) of As-contaminated soils and groundwater may be a cost-effective in situ remedial option. It relies on the site intrinsic assimilative capacity and allows in-place cleanup. Sorption to solid phases is the principal mechanism immobilizing As in soils and removing it from groundwater. Hydroxides of iron, aluminum and manganese, clay and sulfide minerals, and natural organic matter are commonly associated with soils and aquifer sediments, and have been shown to be significant As adsorbents. The extent of sorption is influenced by As speciation and the site geochemical conditions such as pH, redox potential, and the co-occurring ions. Microbial activity may catalyze the transformation of As species, or mediate redox reactions thus influencing As mobility. Plants that are capable of hyperaccumulating As may translocate As from contaminated soils and groundwater to their tissues, providing the basis for phytoremediation. However, NA is subject to hydrological changes and may take substantial periods of time, thus requiring long-term monitoring. The current understanding of As NA processes remains limited. Sufficient site characterization is critical to the success of NA. Further research is required to develop conceptual and mathematical models to predict the fate and transport of As and to evaluate the site NA capacity. Engineering enhanced NA using environmentally benign products may be an effective alternative.

  8. Soil air CO2 concentration as an integrative parameter of soil structure

    NASA Astrophysics Data System (ADS)

    Ebeling, Corinna; Gaertig, Thorsten; Fründ, Heinz-Christian

    2015-04-01

    The assessment of soil structure is an important but difficult issue and normally takes place in the laboratory. Typical parameters are soil bulk density, porosity, water or air conductivity or gas diffusivity. All methods are time-consuming. The integrative parameter soil air CO2 concentration ([CO2]) can be used to assess soil structure in situ and in a short time. Several studies highlighted that independent of soil respiration, [CO2] in the soil air increases with decreasing soil aeration. Therefore, [CO2] is a useful indicator of soil aeration. Embedded in the German research project RÜWOLA, which focus on soil protection at forest sites, we investigated soil compaction and recovery of soil structure after harvesting. Therefore, we measured soil air CO2 concentrations continuously and in single measurements and compared the results with the measurements of bulk density, porosity and gas diffusivity. Two test areas were investigated: At test area 1 with high natural regeneration potential (clay content approx. 25 % and soil-pH between 5 and 7), solid-state CO2-sensors using NDIR technology were installed in the wheel track of different aged skidding tracks in 5 and 10 cm soil depths. At area 2 (acidic silty loam, soil-pH between 3.5 and 4), CO2-sensors and water-tension sensors (WatermarkR) were installed in 6 cm soil depth. The results show a low variance of [CO2] in the undisturbed soil with a long term mean from May to June 2014 between 0.2 and 0.5 % [CO2] in both areas. In the wheel tracks [CO2] was consistently higher. The long term mean [CO2] in the 8-year-old-wheel track in test area 1 is 5 times higher than in the reference soil and shows a high variation (mean=2.0 %). The 18-year-old wheel track shows a long-term mean of 1.2 % [CO2]. Furthermore, there were strong fluctuations of [CO2] in the wheel tracks corresponding to precipitation and humidity. Similar results were yielded with single measurements during the vegetation period using a portable

  9. A Geochemical Reaction Model for Titration of Contaminated Soil and Groundwater at the Oak Ridge Reservation

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Parker, J. C.; Gu, B.; Luo, W.; Brooks, S. C.; Spalding, B. P.; Jardine, P. M.; Watson, D. B.

    2007-12-01

    This study investigates geochemical reactions during titration of contaminated soil and groundwater at the Oak Ridge Reservation in eastern Tennessee. The soils and groundwater exhibits low pH and high concentrations of aluminum, calcium, magnesium, manganese, various trace metals such as nickel and cobalt, and radionuclides such as uranium and technetium. The mobility of many of the contaminant species diminishes with increasing pH. However, base additions to increase pH are strongly buffered by various precipitation/dissolution and adsorption/desorption reactions. The ability to predict acid-base behavior and associated geochemical effects is thus critical to evaluate remediation performance of pH manipulation strategies. This study was undertaken to develop a practical but generally applicable geochemical model to predict aqueous and solid-phase speciation during soil and groundwater titration. To model titration in the presence of aquifer solids, an approach proposed by Spalding and Spalding (2001) was utilized, which treats aquifer solids as a polyprotic acid. Previous studies have shown that Fe and Al-oxyhydroxides strongly sorb dissolved Ni, U and Tc species. In this study, since the total Fe concentration is much smaller than that of Al, only ion exchange reactions associated with Al hydroxides are considered. An equilibrium reaction model that includes aqueous complexation, precipitation, ion exchange, and soil buffering reactions was developed and implemented in the code HydroGeoChem 5.0 (HGC5). Comparison of model results with experimental titration curves for contaminated groundwater alone and for soil- water systems indicated close agreement. This study is expected to facilitate field-scale modeling of geochemical processes under conditions with highly variable pH to develop practical methods to control contaminant mobility at geochemically complex sites.

  10. Groundwater-soil-crop relationship with respect to arsenic contamination in farming villages of Bangladesh--a preliminary study.

    PubMed

    Kurosawa, Kiyoshi; Egashira, Kazuhiko; Tani, Masakazu; Jahiruddin, M; Moslehuddin, Abu Zofar Md; Rahman, Zulfikar Md

    2008-11-01

    To clarify the groundwater-soil-crop relationship with respect to arsenic (As) contamination, As concentration was measured in tubewell (TW) water, surface soil from farmyards and paddy fields, and fresh taro (Colocasia esculenta) leaves from farmyards in the farming villages of Bangladesh. The As concentration in TW water from farmyards was at least four times higher than the Bangladesh drinking water standard, and the concentration in fresh taro leaves was equal to or higher than those reported previously for leafy vegetables in Bangladesh. As concentration of surface soils in both farmyards and paddy fields was positively correlated with that of the TW water. Further, the concentration in surface soil was positively correlated with levels in fresh taro leaves in the farmyard. This study, therefore, clarified the groundwater-soil-crop relationship in farmyards and the relationship between groundwater-soil in paddy fields to assess the extent of As contamination in Bangladeshi villages.

  11. Groundwater level and nitrate concentration trends on Mountain Home Air Force Base, southwestern Idaho

    USGS Publications Warehouse

    Williams, Marshall L.

    2014-01-01

    Mountain Home Air Force Base in southwestern Idaho draws most of its drinking water from the regional aquifer. The base is located within the State of Idaho's Mountain Home Groundwater Management Area and is adjacent to the State's Cinder Cone Butte Critical Groundwater Area. Both areas were established by the Idaho Department of Water Resources in the early 1980s because of declining water levels in the regional aquifer. The base also is listed by the Idaho Department of Environmental Quality as a nitrate priority area. The U.S. Geological Survey, in cooperation with the U.S. Air Force, began monitoring wells on the base in 1985, and currently monitors 25 wells for water levels and 17 wells for water quality, primarily nutrients. This report provides a summary of water-level and nitrate concentration data collected primarily between 2001 and 2013 and examines trends in those data. A Regional Kendall Test was run to combine results from all wells to determine an overall regional trend in water level. Groundwater levels declined at an average rate of about 1.08 feet per year. Nitrate concentration trends show that 3 wells (18 percent) are increasing in nitrate concentration trend, 3 wells (18 percent) show a decreasing nitrate concentration trend, and 11 wells (64 percent) show no nitrate concentration trend. Six wells (35 percent) currently exceed the U.S. Environmental Protection Agency's maximum contaminant limit of 10 milligrams per liter for nitrate (nitrite plus nitrate, measured as nitrogen).

  12. Remediation of arsenic-contaminated soils and groundwaters

    DOEpatents

    Peters, Robert W.; Frank, James R.; Feng, Xiandong

    1998-01-01

    An in situ method for extraction of arsenic contaminants from a soil medium and remediation of the medium including contacting the medium with an extractant solution, directing the solution within and through the medium, and collecting the solution and contaminants. The method can also be used for arsenate and/or arsenite removal.

  13. Remediation of arsenic-contaminated soils and groundwaters

    DOEpatents

    Peters, R.W.; Frank, J.R.; Feng, X.

    1998-06-23

    An in situ method is described for extraction of arsenic contaminants from a soil medium and remediation of the medium including contacting the medium with an extractant solution, directing the solution within and through the medium, and collecting the solution and contaminants. The method can also be used for arsenate and/or arsenite removal. 8 figs.

  14. MODELS FOR LEACHING OF PESTICIDES IN SOILS AND GROUNDWATER

    EPA Science Inventory

    Models are developed which describe leaching of pesticides in the root zone and the intermediate vadose zone, and flushing of residual solute mass in the aquifer. Pollutants' loss pathways in the soil, such as volatilization, crop uptake, and biochemical decay, are emphasized, a...

  15. Assessing soil and groundwater contamination from biofuel spills.

    PubMed

    Chen, Colin S; Shu, Youn-Yuen; Wu, Suh-Huey; Tien, Chien-Jung

    2015-03-01

    Future modifications of fuels should include evaluation of the proposed constituents for their potential to damage environmental resources such as the subsurface environment. Batch and column experiments were designed to simulate biofuel spills in the subsurface environment and to evaluate the sorption and desorption behavior of target fuel constituents (i.e., monoaromatic and polyaromatic hydrocarbons) in soil. The extent and reversibility of the sorption of aromatic biofuel constituents onto soil were determined. When the ethanol content in ethanol-blended gasoline exceeded 25%, enhanced desorption of the aromatic constituents to water was observed. However, when biodiesel was added to diesel fuel, the sorption of target compounds was not affected. In addition, when the organic carbon content of the soil was higher, the desorption of target compounds into water was lower. The empirical relationships between the organic-carbon normalized sorption coefficient (Koc) and water solubility and between Koc and the octanol-water partition coefficient (Kow) were established. Column experiments were carried out for the comparison of column effluent concentration/mass from biofuel-contaminated soil. The dissolution of target components depended on chemical properties such as the hydrophobicity and total mass of biofuel. This study provides a basis for predicting the fate and transport of hydrophobic organic compounds in the event of a biofuel spill. The spill scenarios generated can assist in the assessment of biofuel-contaminated sites.

  16. Fiscal Year 2009 Annual Report for Operable Unit 3-14, Tank Farm Soil and INTEC Groundwater

    SciTech Connect

    Forsythe, Howard S.

    2010-04-10

    This annual report summarizes maintenance, monitoring, and inspection activities performed to implement the selected remedy for Waste Area Group 3, Operable Unit 3-14, Tank Farm soil and groundwater at the Idaho Nuclear Technology and Engineering Center located within the Idaho National Laboratory Site. Results from monitoring perched water and groundwater at the Idaho Nuclear Technology and Engineering Center are also presented.

  17. Impacts of soil and groundwater salinization on tree crop performance in post-tsunami Aceh Barat, Indonesia

    NASA Astrophysics Data System (ADS)

    Marohn, C.; Distel, A.; Dercon, G.; Wahyunto; Tomlinson, R.; Noordwijk, M. v.; Cadisch, G.

    2012-09-01

    The Indian Ocean tsunami of December 2004 had far reaching consequences for agriculture in Aceh province, Indonesia, and particularly in Aceh Barat district, 150 km from the seaquake epicentre. In this study, the spatial distribution and temporal dynamics of soil and groundwater salinity and their impact on tree crops were monitored in Aceh Barat from 2006 to 2008. On 48 sampling points along ten transects, covering 40 km of coastline, soil and groundwater salinity were measured and related to mortality and yield depression of the locally most important tree crops. Given a yearly rainfall of over 3000 mm, initial groundwater salinity declined rapidly from over 10 to less than 2 mS cm-1 within two years. On the other hand, seasonal dynamics of the groundwater table in combination with intrusion of saline water into the groundwater body led to recurring elevated salinity, sufficient to affect crops. Tree mortality and yield depression in the flooded area varied considerably between tree species. Damage to coconut (65% trees damaged) was related to tsunami run-up height, while rubber (50% trees damaged) was mainly affected by groundwater salinity. Coconut yields (-35% in average) were constrained by groundwater Ca2+ and Mg2+, while rubber yields (-65% on average) were related to groundwater chloride, pH and soil sodium. These findings have implications on planting deep-rooted tree crops as growth will be constrained by ongoing oscillations of the groundwater table and salinity.

  18. VERTICAL PROFILING OF VOCS IN GROUNDWATER AND SOIL VAPORS TO EVALUATE THE RISK OF VAPOR INTRUSION

    EPA Science Inventory

    The Draft EPA Subsurface Vapor Intrusion Guidance Document was established to address the incremental increases in exposures and risks from subsurface contaminants that may be intruding into indoor air@. The document utilizes attenuation factors based on indoor air/soil gas or i...

  19. Effects of Air Drying on Soil Available Phosphorus in Two Grassland Soils

    NASA Astrophysics Data System (ADS)

    Schaerer, M.; Frossard, E.; Sinaj, S.

    2003-04-01

    Mobilization of P from the soil to ground and surface water is principally determined by the amount of P in the soil and physico-chemical as well as biological processes determining the available P-pool that is in equilibrium with soil solution. Soil available P is commonly estimated on air dry soil using a variety of methods (extraction with water, dilute acids and bases, anion exchange resin, isotopic exchange or infinite sinks). Recently, attempts have been made to use these measurements to define the potential for transport of P from soil to water by overland flow or subsurface flow. The effect of air drying on soil properties in general, and plant nutrient status in particular, have been subject of a number of studies. The main objective of this paper was to evaluate the effect of air-drying on soil properties and available P. For this experiment, grassland soils were sampled on two study sites located on slopes in the watershed of Lake Greifensee, 25 km south-east of Zurich. Both soils (0-4 cm depth) are rich in P with 1.7 and 1.3 g kg-1 total P at site I and site II, respectively. The concentrations on isotopically exchangeable P within 1 minute (E1min, readily available P) for the same depth were also very high, 58 and 27 mg P kg soil-1 for the site I and II, respectively. In the present study both field moist and air dried soil samples were analyzed for microbial P (Pmic), resin extractable P (P_r), isotopically exchangeable P (E1min) and amorphous Al and Fe (Alox, Feox). Generally, the microbial P in field moist soils reached values up to 120 mg P/kg soil, whereas after drying they decreased by 73% in average for both soils. On the contrary to Pmic, available P estimated by different methods strongly increased after drying of the soil samples. The concentration of phosphate ions in the soil solution c_p, E1min and P_r were 4.2, 2.2 and 2 times higher in dry soils than in field moist soils. The increase in available P shows significant semilogarithmic

  20. Remediation of nonaqueous phase liquid polluted sites using surfactant-enhanced air sparging and soil vapor extraction.

    PubMed

    Qin, Chuan-Yu; Zhao, Yong-Sheng; Su, Yan; Zheng, Wei

    2013-02-01

    A two-dimensional laboratory sand tank was installed to study the remediation efficiency of surfactant-enhanced air sparging (-SEAS) coupled with soil vapor extraction (SVE) in nonaqueous phase liquid (NAPL) polluted sites. During initial stages of remediation, it was more reasonable to use conventional air sparging coupled with SVE. When most free NAPLs were removed and contaminant removal rate was maintained at a relatively low level, surfactant was added to the groundwater. During enhanced remediation, lower interfacial tension caused residual NAPLs in the porous media to slightly migrate, making the downstream contaminant concentration somewhat higher. The polluted area, however, was not more enlarged than before. The decrease in surface tension resulted in increased air saturation in the groundwater and the extent of the air influence zone. After 310 hours, 78.7% of the initial chlorobenzene mass had volatilized, 3.3% had migrated out of the sand profile, 17.5% was in the vadose zone, and 0.5% remained in the groundwater, thus revealing that SEAS/SVE can effectively improve the remediation of NAPL polluted sites.

  1. Determination of fumaric acid, maleic acid, and phthalic acid in groundwater and soil

    SciTech Connect

    Dietz, E.A.; Singley, K.F. . Technology Center)

    1994-01-01

    When present at > 1 [mu]g/mL, each title compound was determined in groundwater by ion-exclusion chromatography after sample acidification and filtration. For groundwater with one or all analyte concentrations of < 1 [mu]g/mL, the acid anions were first concentrated from a 100-mL sample using a quaternary amine anion-exchange cartridge. The acids were recovered by eluting the cartridge with 1 mL of N H[sub 2]SO[sub 4] and 2-mL deionized water washes; this solution then was examined by anion-exclusion chromatography. Analytes were monitored with a UV detector operated at 200 nm. The analysis procedures for groundwater were validated with solutions which were fortified with from 50 ng/mL to 200 [mu]g/mL of each analyte; recoveries ranged from 90 to 110%. The soil method was validated using fortified samples which contained each acid at concentrations of from 5 to 160 [mu]g/g. Recovery values were between 81 and 120%. For samples exhibiting minimal detector response from compounds other than the acids of interest, 100-[mu]L injection volumes provided an estimated detection limit of 1 [mu]g/g for soil and 10 ng/mL for groundwater.

  2. The Office of Groundwater & Soil Remediation Fiscal Year 2011 Research & Development Program

    SciTech Connect

    Gerdes, Kurt D.; Chamberlain, Grover S.; Aylward, R. S.; Cercy, Mike; Seitz, Roger; Ramirez, Rosa; Skubal, Karen L.; Marble, Justin; Wellman, Dawn M.; Bunn, Amoret L.; Liang, Liyuan; Pierce, Eric M.

    2011-12-02

    The U.S. Department of Energy’s (DOE) Office of Groundwater and Soil Remediation supports applied research and technology development (AR&TD) for remediation of environments contaminated by legacy nuclear waste. The program centers on delivering advanced scientific approaches and technologies from highly-leveraged, strategic investments that maximize impact to reduce risk and life-cycle cleanup costs. The current groundwater and soil remediation program consists of four applied programmatic areas: • Deep Vadose Zone – Applied Field Research Initiative • Attenuation Based Remedies – Applied Field Research Initiative • Remediation of Mercury and Industrial Contaminants – Applied Field Research Initiative • Advanced Simulation Capability for Environmental Management. This paper provides an overview of the applied programmatic areas, fiscal year 11 accomplishments, and their near-term technical direction.

  3. Evidence of terrestrial discharge of deep groundwater on the Canadian Shield from helium in soil gases

    SciTech Connect

    Gascoyne, M.; Sheppard, M.I. )

    1993-11-01

    Assessment of the impact of deep geological disposal of nuclear fuel wastes at a site in the Canadian Shield requires knowledge of the location and size of areas of discharge of deep groundwater from the vicinity of the underground disposal vault. A strong He anomaly has been detected in soil gases in a 10 X 10 m area of wetland on the banks of Boggy Creek, near Lac du Bonnet, Manitoba. The area has He concentrations in near-surface soils as high as 360 nL[center dot]L[sup [minus]1] and is assumed to indicate discharge of He-rich groundwater through a permeable subsurface bedrock fracture. Elevated Cl[sup [minus

  4. [Application of tiered approach to assess the impact of backfilling remediated soil on groundwater].

    PubMed

    Zhong, Mao-Sheng; Jiang, Lin; Yao, Jue-Jun; Fan, Yan-Ling; Xia, Tian-Xiang; Li, Ting-Ting; Tian, Mei-Ying

    2013-03-01

    The tiered approach for assessing the impact of backfilling treated contaminated soil on groundwater was presented in details with a case study. The soil was contaminated by 1,2-dicholorenthane and 9 other organic pollutants and had been remediated before backfilling to meet the pre-set remediation goals based on health risk assessment. The results from tiered I assessment indicate that the concentrations of 8 contaminants in the leachate of the backfilling soil layer would exceed the assessment standards probably leading to groundwater contamination. However, the results from tiered II assessment, in which the adsorption and retardation of vadose zone soil was taken into account and the concentrations of pollutants reaching the groundwater table were predicated, reveal that only the concentrations of 6 contaminants would exceed the assessment standards. Further, taking the dilution and mixing of the groundwater into consideration, tiered III assessment was adopted and the results reveal that only 4 contaminants were beyond the standards. Finally, tiered IV assessment, aiming at predicting the concentration at the target well downstream, was carried out by considering the retardation of contaminants in saturated layer, and the results indicate only 1 pollutant was above the assessment standard. Therefore, it can be seen that the predicted concentrations of the target pollutants at advanced assessment levels will be closer to those at the target drinking water well and the amount of contaminants whose initially-set remediation goals need to be modified will decrease correspondingly, indicating the reduction in pollution prevention cost, although more efforts should be made and more field data should be collected to implement the advance assessment level.

  5. Contamination of soils and groundwater with new organic micropollutants: A review

    NASA Astrophysics Data System (ADS)

    Vodyanitskii, Yu. N.; Yakovlev, A. S.

    2016-05-01

    The input of organic micro- and nanopollutants to the environment has grown in recent years. This vast class of substances is referred to as emerging micropollutants, and includes organic chemicals of industrial, agricultural, and municipal provenance. There are three main sources of emerging pollutants coming to the environment, i.e., (1) upon soil fertilization with sewage and sewage sludge; (2) soil irrigation with reclaimed wastewater and (3) due to filtration from municipal landfills of solid wastes. These pollutants contaminate soil, affect its inhabitants; they are also consumed by plants and penetrate to the groundwater. The pharmaceuticals most strongly affect the biota (microorganisms, earthworms, etc.). The response of microorganisms in the contaminated soil is controlled not only by the composition and the number of emerging pollutants but also by the geochemical environment.

  6. Multivariate analysis of trace metals in textile effluents in relation to soil and groundwater.

    PubMed

    Manzoor, S; Shah, Munir H; Shaheen, N; Khalique, A; Jaffar, M

    2006-09-01

    This paper deals with the multivariate analysis of metal data in effluents, soil and groundwater to find the distribution and source identification of the selected metals in the three media. Samples were collected from three textile industries located in Hattar Industrial Estate, Pakistan. Metals were estimated by flame atomic absorption spectrophotometry. The results showed elevated levels of Cr, Pb, Ni, Co, Fe, Ca, Na, K and Zn in these media, following the order: soil>effluent>water. Principle component analysis (PCA) of the data showed that the textile effluents are contaminating the soil wherein Cr and Pb were dominant toxic metals having concentrations of 5.96 mg/kg and 4.46 mg/kg, respectively. Other toxic metals such as Co, Cd, Zn, Ni, Mn and Fe, were found to have common origin in the textile effluents. The correlation study along with linear regression and PCA, supported the fact that various elevated metal concentrations emerged from the textile industrial effluents ultimately leading to contamination of the soil and groundwater in their proximity. The estimated metal levels in the water/soil system are compared with the safe limits laid down by WHO.

  7. Near-stream soil water groundwater coupling in the headwaters of the Afon Hafren, Wales: Implications for surface water quality

    NASA Astrophysics Data System (ADS)

    Haria, Atul H.; Shand, Paul

    2006-12-01

    SummaryHard-rock acid headwater catchments typically exhibit a rapid streamflow response and concomitant rapid mobilisation of soil-derived solutes, such as aluminium, into the aquatic environment during storm events. The rapid stream responses are paradoxically associated with pre-event water dominating the storm hydrograph, however the sources and mechanisms by which 'old' water enters the stream channel and interacts with the soil horizons are still poorly understood. To investigate these processes a detailed and novel field study was established in the riparian zone and lower hillslopes of the Hafren catchment at Plynlimon, mid-Wales. This study showed that shallow bedrock groundwaters discharge into the stream channel. Pressure wave propagation in response to recharge further upslope caused a rapid displacement of shallow groundwaters up into the soils in the near-stream hillslope. A lateral fast flow horizon transported water down slope as interflow at the soil-bedrock interface such that the upper soil horizons remained largely unsaturated. Only where there was a discontinuity in the lateral fast flow horizon was water forced up as an ephemeral spring discharge at the soil surface. At this site, the major zone of soil water-groundwater coupling was in a narrow (20-25 m) strip next to the stream channel. The zone of soil water-groundwater interaction next to the stream channel is likely to depend on the nature of the lateral flow pathways and the hillslope characteristic. This study has shown the importance of the near-stream environment as a locus for soil waters that are bedrock groundwater derived; these groundwaters dominate processes in the deepest soil horizons from where soil components such as aluminium are sourced. Understanding these physical processes is fundamental for understanding upland catchment functioning and has important implications for solute transport modelling and for the sustainable management of surface water systems and stream

  8. 3-D modeling useful tool for planning. [mapping groundwater and soil pollution and subsurface features

    SciTech Connect

    Calmbacher, C.W. )

    1992-12-01

    Visualizing and delineating subsurface geological features, groundwater contaminant plumes, soil contamination, geological faults, shears and other features can prove invaluable to environmental consultants, engineers, geologists and hydrogeologists. Three-dimensional modeling is useful for a variety of applications from planning remediation to site planning design. The problem often is figuring out how to convert drilling logs, map lists or contaminant levels from soil and groundwater into a 3-D model. Three-dimensional subsurface modeling is not a new requirement, but a flexible, easily applied method of developing such models has not always been readily available. LYNX Geosystems Inc. has developed the Geoscience Modeling System (GMS) in answer to the needs of those regularly having to do three-dimensional geostatistical modeling. The GMS program has been designed to allow analysis, interpretation and visualization of complex geological features and soil and groundwater contamination. This is a powerful program driven by a 30 volume modeling technology engine. Data can be entered, stored, manipulated and analyzed in ways that will present very few limitations to the user. The program has selections for Geoscience Data Management, Geoscience Data Analysis, Geological Modeling (interpretation and analysis), Geostatistical Modeling and an optional engineering component.

  9. Soil zinc content, groundwater usage, and prostate cancer incidence in South Carolina

    PubMed Central

    Burch, James B.; Hussey, Jim; Temples, Tom; Bolick-Aldrich, Susan; Mosley-Broughton, Catishia; Liu, Yuan; Hebert, James R.

    2010-01-01

    Background Prostate cancer (PrCA) incidence in South Carolina (SC) exceeds the national average, particularly among African Americans (AAs). Though data are limited, low environmental zinc exposures and down-regulation of prostatic zinc transporter proteins among AAs may explain, in part, the racial PrCA disparity. Methods Age-adjusted PrCA rates were calculated by census tract. Demographic data were obtained from the 1990 census. Hazardous waste site locations and soil zinc concentrations were obtained from existing federal and state databases. A geographic information system and Poisson regression were used to test the hypothesis that census tracts with reduced soil zinc concentrations, elevated groundwater use, or more agricultural or hazardous waste sites had elevated PrCA risks. Results Census tracts with high groundwater use and low zinc concentrations had higher PrCA rate ratios (RR: 1.270; 95% confidence interval: 1.079, 1.505). This effect was not more apparent in areas populated primarily by AAs. Conclusion Increased PrCA rates were associated with reduced soil zinc concentrations and elevated groundwater use, although this observation is not likely to contribute to SC’s racial PrCA disparity. Statewide mapping and statistical modeling of relationships between environmental factors, demographics, and cancer incidence can be used to screen hypotheses focusing on novel PrCA risk factors. PMID:18949566

  10. Effect of natural organic matter on arsenic release from soils and sediments into groundwater.

    PubMed

    Wang, Suiling; Mulligan, Catherine N

    2006-06-01

    Arsenic (As) contamination in groundwater has received significant attention recently. Natural and anthropogenic sources contribute to the worldwide occurrence of As contamination. As speciation is an important factor related to its toxic and mobile behavior. The release of As from soils and sediments into groundwater is governed by several geophysicochemical processes, of which, As sorption behavior is of principle significance. This review paper summarizes existing information regarding the effects of natural organic matter (NOM) on the fate and mobility of As species in the environment. NOM may enhance the release of As from soils and sediments into the soil solution, thereby facilitating As leaching into the groundwater. The main influencing mechanisms include competition for available adsorption sites, formation of aqueous complexes, and/or changes in the redox potential of site surfaces and As redox speciation. NOM may also serve as binding agents, thereby reducing As mobility. However, comparably little research has been performed on this aspect. Since most investigations have been done on purified minerals under laboratory conditions, further research involving various geological materials under natural environmental conditions is required. Development of proper geochemical conceptual models may provide means of predicting the role of NOM in arsenic leaching and/or immobilization.

  11. Biochar- and phosphate-induced immobilization of heavy metals in contaminated soil and water: implication on simultaneous remediation of contaminated soil and groundwater.

    PubMed

    Liang, Yuan; Cao, Xinde; Zhao, Ling; Arellano, Eduardo

    2014-03-01

    Long-term wastewater irrigation or solid waste disposal has resulted in the heavy metal contamination in both soil and groundwater. It is often separately implemented for remediation of contaminated soil or groundwater at a specific site. The main objective of this study was to demonstrate the hypothesis of simultaneous remediation of both heavy metal contaminated soil and groundwater by integrating the chemical immobilization and pump-and-treat methods. To accomplish the objective, three experiments were conducted, i.e., an incubation experiment was first conducted to determine how dairy-manure-derived biochar and phosphate rock tailing induced immobilization of Cd in the Cd-contaminated soils; second, a batch sorption experiment was carried out to determine whether the pre-amended contaminated soil still had the ability to retain Pb, Zn and Cd from aqueous solution. BCR sequential extraction as well as XRD and SEM analysis were conducted to explore the possible retention mechanism; and last, a laboratory-scale model test was undertaken by leaching the Pb, Zn, and Cd contaminated groundwater through the pre-amended contaminated soils to demonstrate how the heavy metals in both contaminated soil and groundwater were simultaneously retained and immobilized. The incubation experiment showed that the phosphate biochar were effective in immobilizing soil Cd with Cd concentration in TCLP (toxicity characteristics leaching procedure) extract reduced by 19.6 % and 13.7 %, respectively. The batch sorption experiment revealed that the pre-amended soil still had ability to retain Pb, Zn, and Cd from aqueous solution. The phosphate-induced metal retention was mainly due to the metal-phosphate precipitation, while both sorption and precipitation were responsible for the metal stabilization in the biochar amendment. The laboratory-scale test demonstrated that the soil amended with phosphate removed groundwater Pb, Zn, and Cd by 96.4 %, 44.6 %, and 49.2 %, respectively, and the

  12. Biochar- and phosphate-induced immobilization of heavy metals in contaminated soil and water: implication on simultaneous remediation of contaminated soil and groundwater.

    PubMed

    Liang, Yuan; Cao, Xinde; Zhao, Ling; Arellano, Eduardo

    2014-03-01

    Long-term wastewater irrigation or solid waste disposal has resulted in the heavy metal contamination in both soil and groundwater. It is often separately implemented for remediation of contaminated soil or groundwater at a specific site. The main objective of this study was to demonstrate the hypothesis of simultaneous remediation of both heavy metal contaminated soil and groundwater by integrating the chemical immobilization and pump-and-treat methods. To accomplish the objective, three experiments were conducted, i.e., an incubation experiment was first conducted to determine how dairy-manure-derived biochar and phosphate rock tailing induced immobilization of Cd in the Cd-contaminated soils; second, a batch sorption experiment was carried out to determine whether the pre-amended contaminated soil still had the ability to retain Pb, Zn and Cd from aqueous solution. BCR sequential extraction as well as XRD and SEM analysis were conducted to explore the possible retention mechanism; and last, a laboratory-scale model test was undertaken by leaching the Pb, Zn, and Cd contaminated groundwater through the pre-amended contaminated soils to demonstrate how the heavy metals in both contaminated soil and groundwater were simultaneously retained and immobilized. The incubation experiment showed that the phosphate biochar were effective in immobilizing soil Cd with Cd concentration in TCLP (toxicity characteristics leaching procedure) extract reduced by 19.6 % and 13.7 %, respectively. The batch sorption experiment revealed that the pre-amended soil still had ability to retain Pb, Zn, and Cd from aqueous solution. The phosphate-induced metal retention was mainly due to the metal-phosphate precipitation, while both sorption and precipitation were responsible for the metal stabilization in the biochar amendment. The laboratory-scale test demonstrated that the soil amended with phosphate removed groundwater Pb, Zn, and Cd by 96.4 %, 44.6 %, and 49.2 %, respectively, and the

  13. On the air-filled effective porosity parameter of Rogers and Nielson's (1991) bulk radon diffusion coefficient in unsaturated soils.

    PubMed

    Saâdi, Zakaria

    2014-05-01

    The radon exhalation rate at the earth's surface from soil or rock with radium as its source is the main mechanism behind the radon activity concentrations observed in both indoor and outdoor environments. During the last two decades, many subsurface radon transport models have used Rogers and Nielson's formula for modeling the unsaturated soil bulk radon diffusion coefficient. This formula uses an "air-filled effective porosity" to account for radon adsorption and radon dissolution in the groundwater. This formula is reviewed here, and its hypotheses are examined for accuracy in dealing with subsurface radon transport problems. The author shows its limitations by comparing one dimensional steady-state analytical solutions of the two-phase (air/water) transport equation (Fick's law) with Rogers and Nielson's formula. For radon diffusion-dominated transport, the calculated Rogers and Nielson's radon exhalation rate is shown to be unrealistic as it is independent of the values of the radon adsorption and groundwater dissolution coefficients. For convective and diffusive transport, radon exhalation rates calculated using Fick's law and this formula agree only for high values of gas-phase velocity and groundwater saturation. However, these conditions are not usually met in most shallow subsurface environments where radon migration takes place under low gas phase velocities and low water saturation.

  14. On the air-filled effective porosity parameter of Rogers and Nielson's (1991) bulk radon diffusion coefficient in unsaturated soils.

    PubMed

    Saâdi, Zakaria

    2014-05-01

    The radon exhalation rate at the earth's surface from soil or rock with radium as its source is the main mechanism behind the radon activity concentrations observed in both indoor and outdoor environments. During the last two decades, many subsurface radon transport models have used Rogers and Nielson's formula for modeling the unsaturated soil bulk radon diffusion coefficient. This formula uses an "air-filled effective porosity" to account for radon adsorption and radon dissolution in the groundwater. This formula is reviewed here, and its hypotheses are examined for accuracy in dealing with subsurface radon transport problems. The author shows its limitations by comparing one dimensional steady-state analytical solutions of the two-phase (air/water) transport equation (Fick's law) with Rogers and Nielson's formula. For radon diffusion-dominated transport, the calculated Rogers and Nielson's radon exhalation rate is shown to be unrealistic as it is independent of the values of the radon adsorption and groundwater dissolution coefficients. For convective and diffusive transport, radon exhalation rates calculated using Fick's law and this formula agree only for high values of gas-phase velocity and groundwater saturation. However, these conditions are not usually met in most shallow subsurface environments where radon migration takes place under low gas phase velocities and low water saturation. PMID:24670909

  15. Groundwater Availability Alters Soil-plant Nutrient Cycling in a Stand of Invasive, N-fixing Phreatophytes

    NASA Astrophysics Data System (ADS)

    Dudley, B. D.; Miyazawa, Y.; Hughes, F.; Ostertag, R.; Kettwich, S. K.; MacKenzie, R.; Dulaiova, H.; Waters, C. A.; Bishop, J.; Giambelluca, T. W.

    2013-12-01

    N-fixing phreatophytic trees are common in arid and semi-arid regions worldwide, and can play significant roles in modifying hydrology and soil-plant nutrient cycling where they are present. In light of reductions in groundwater levels in many arid regions we estimated annual transpiration rates at a stand level, and alterations to C, N and P accretion in soils as a function of groundwater depth in a ca.120 year old stand of Prosopis pallida along an elevation gradient in coastal leeward Hawaii. We measured sapflow and stand level sapwood area to quantify transpiration, and calculated groundwater transpiration rates using P. pallida stem water δ18O values. By measuring soil resistivity, we were able to compare the volume of groundwater transpired by these trees to groundwater depth across the stand. We examined nutrient deposition and accretion in soils in lowland areas of the stand with accessible shallow groundwater, compared to upland areas with no groundwater access, as indicated by stem water δ18O values. Resistivity results suggested that groundwater was at a height close to sea level throughout the stand. Transpiration was around 1900 m3 ha-1 year-1 in the areas of the stand closest to the sea (where groundwater was at around 1-4 m below ground level) and decreased to around a tenth of that volume where groundwater was not accessible. Litterfall rates over the course of the year studied were 17 times greater at lowland sites, but this litterfall contributed ca. 24 times the N, and 35 times the P of upland sites. Thus, groundwater access contributed to the total mass of nitrogen and phosphorus deposited in the form of litter through higher litter quantity and quality. Total N content of soils was 4.7 times greater and inorganic N pools were eight times higher at lowland plots. These results suggest that groundwater depth can have strong effects on soil-plant nutrient cycling, so that reductions in the availability of shallow groundwater are likely to impact

  16. In Situ Formation of Calcium Apatite in Soil for Sequestering Contaminants in Soil and Groundwater

    SciTech Connect

    Moore, Robert; Szecsody, Jim; Thompson, Mike

    2015-10-20

    A new method for in situ formation of a calcium apatite permeable reactive barrier that is a groundbreaking technology for containing radioactive/heavy metal contaminants threatening groundwater supplies.

  17. Comparing risk assessment at the site and community scales via Monte Carlo simulations with a new coupled groundwater-vapour-indoor air model

    NASA Astrophysics Data System (ADS)

    Mumford, K. G.; Mustafa, N. A.; Gerhard, J.

    2012-12-01

    At many former industrial sites, nonaqueous phase liquid (NAPL) contamination presents a significant limitation to site closure and brownfield redevelopment. Achieving site closure means soil and/or groundwater remediation to a level at which the associated risk is reduced to an acceptable level. In some jurisdictions, this risk is evaluated at the site boundary even if the critical risk receptors are located in the surrounding community; the consequence may be a site left untreated because the remediation target is technically or economically impractical. The goal of this study was to explore the implications of assessing risk at the site boundary versus in the community and the factors that affect the differences between the two. Because the controlling risk pathway for many volatile organic compounds (VOCs) is the contamination of indoor air, risk assessment at the community scale requires simulation tools that can predict the transport of dissolved VOCs in groundwater followed by vapour intrusion into residential houses. Existing tools and research had focused on vapour intrusion only in the near vicinity of the source (i.e., scale of meters) and primarily at steady s tate. Therefore, this work developed a novel numerical simulator that coupled an established groundwater flow and contaminant transport model to a state-of-the-art vapor intrusion model, which enables the prediction of indoor air concentrations in response to an evolving groundwater plume at the community (i.e., kilometre) scale. In the first phase of this work, the extent of source zone remediation required to achieve regulatory compliance at the site boundary was compared to the extent required to achieve compliance at receptors in the community. The sensitivity of this difference to physicochemical properties of the contaminant and whether compliance was based on groundwater or indoor air risk receptors was evaluated. In the second phase of this work, the influence of heterogeneity on the

  18. Helium 4 and radon 222 concentrations in groundwater and soil as indicators of zones of fracture concentration in unexposed rock

    SciTech Connect

    Banwell, G.M.; Parizek, R.R.

    1988-01-10

    The presence of zones of fracture concentration in unexposed rock may be partially assessed by measuring the concentrations of /sup 4/He and /sup 222/Rn in groundwater and soil gas. Helium 4 in groundwater and soil gas and /sup 222/Rn in groundwater were measured in the vicinity of two intersecting linements in Lehigh County, Pennsylvania. The limeaments are thought to mark deep fracture systems which provide conduits for the migration of /sup 4/He and /sup 222/Rn. High groundwater /sup 4/He concentrations revealed the presence of the two lineaments. Low groundwater /sup 222/Rn activities are found near the lineaments and qualitatively support a numerical model which relates low /sup 222/Rn activity to high fracture transmissivity. Radon 222 activity correlates most strongly with the presence of H/sub 2/S in groundwater, implying that geochemical controls or groundwater circulation patterns strongly influence radon concentration. Soil gas concentrations of /sup 4/He barely exceeded background levels and did not reliably indicate the lineament zones. The data show that groundwater /sup 4/He concentrations may be used to identify fracture zones in unexposed bedrock. copyright American Geophysical Union 1988

  19. Fate of Acrylamide in Soil and Groundwater Systems: Microbial Degradation

    NASA Astrophysics Data System (ADS)

    Labahn, S.; Moser, D.; Arrowood, T.; Young, M.; Robleto, E.

    2007-12-01

    Acrylamide monomer (AMD), a suspected human neurotoxin and carcinogen, is present as a contaminant (up to 0.05%) in commercial preparations of polyacrylamide (PAM). PAM is currently being evaluated for wide-spread use as a temporary water-delivery canal sealant across the western United States. To better constrain potential risks associated with PAM applications, we examined the capacity of natural canal microorganisms to degrade AMD in laboratory and field experiments. Dilution cultivation and enrichment approaches were employed to determine the abundance of culturable microorganisms in several canal habitats which can utilize AMD as a sole nitrogen source (typically 104-106/mL) and a collection of isolates was developed. AMD-degrading microorganisms in our collection fell within a limited diversity of genera including Arthrobacter, Xanthomonas, and Pseudomonas; with the latter demonstrating highest capacity for degrading AMD under laboratory conditions. One strain of Pseudomonas fluorescens, isolated from Klamath Irrigation District (Klamath Falls, OR) canal sediment, was chosen for further study in part because this species is well-studied and ubiquitous. The potential for microbial AMD degradation was tested under laboratory conditions using this strain in repacked short (15 cm) column tests with two relevant soil types (sand and loam). Subsequently, the capacity of mixed natural microbial populations to degrade AMD was examined using soil cores collected from the Highline Canal (Rocky Ford, CO), and canal water/sediment slurries with spiked (5 ppm AMD) in situ bottle tests. Degradation of the monomer in the repacked column experiments was evaluated using a step input of 5 ppm AMD and the canal columns were tested with a range of AMD concentrations (1-5 ppm) followed by quantification with an HPLC. The repacked soil columns inoculated with P. fluorescens demonstrated 80-100% AMD degradation within 12 hours. Natural microbial communities in fresh canal sediment

  20. Natural attenuation of chlorinated solvents at Area 6, Dover Air Force Base: Groundwater biogeochemistry

    USGS Publications Warehouse

    Witt, M.E.; Klecka, G.M.; Lutz, E.J.; Ei, T.A.; Grosso, N.R.; Chapelle, F.H.

    2002-01-01

    Monitored natural attenuation (MNA) has recently emerged as a viable groundwater remediation technology in the United States. Area 6 at Dover Air Force Base (Dover, DE) was chosen as a test site to examine the potential for MNA of tetrachloroethene (PCE) and trichloroethene (TCE) in groundwater and aquifer sediments. A "lines of evidence" approach was used to document the occurrence of natural attenuation. Chlorinated hydrocarbon and biogeochemical data were used to develop a site-specific conceptual model where both anaerobic and aerobic biological processes are responsible for the destruction of PCE, TCE, and daughter metabolites. An examination of groundwater biogeochemical data showed a region of depleted dissolved oxygen with elevated dissolved methane and hydrogen concentrations. Reductive dechlorination likely dominated in the anaerobic portion of the aquifer where PCE and TCE levels were observed to decrease with a simultaneous increase in cis-1,2-dichloroethene (cis-DCE), vinyl chloride (VC), ethene, and dissolved chloride. Near the anaerobic/aerobic interface, concentrations of cis-DCE and VC decreased to below detection limits, presumably due to aerobic biotransformation processes. Therefore, the contaminant and daughter product plumes present at the site appear to have been naturally attenuated by a combination of active anaerobic and aerobic biotransformation processes. ?? 2002 Elsevier Science B.V. All rights reserved.

  1. Evaluation of ground-water flow by particle tracking, Wright-Patterson Air Force Base, Ohio

    USGS Publications Warehouse

    Cunningham, W.L.; Sheets, R.A.; Schalk, C.W.

    1994-01-01

    The U.S. Geological Survey (USGS) and Wright-Patterson Air Force Base (WPAFB) began a Basewide Monitoring Program (BMP) in 1992. The purpose of the BMP was to establish a long-term ground-water and surface- water sampling network in order to (1) characterize current ground-water and surface-water quality; (2) describe water-quality changes as water enters, flows across, and exits Base boundaries; (3) conduct statistical analyses of water quality; and (4) estimate the effect of WPAFB on regional water quality. As part of the BMP, the USGS conducted ground-water particle-tracking analyses based on a ground-water-flow model produced during a previous USGS study. This report briefly describes the previous USGS study, the inherent assumptions of particle-tracking analyses, and information on the regional ground-water-flow field as inferred from particle pathlines. Pathlines for particles placed at the Base boundary and particles placed within identified Installation Restoration Program sites are described.

  2. Natural attenuation of chlorinated solvents at Area 6, Dover Air Force Base: groundwater biogeochemistry.

    PubMed

    Witt, Michael E; Klecka, Gary M; Lutz, Edward J; Ei, Tom A; Grosso, Nancy R; Chapelle, Francis H

    2002-07-01

    Monitored natural attenuation (MNA) has recently emerged as a viable groundwater remediation technology in the United States. Area 6 at Dover Air Force Base (Dover, DE) was chosen as a test site to examine the potential for MNA of tetrachloroethene (PCE) and trichloroethene (TCE) in groundwater and aquifer sediments. A "lines of evidence" approach was used to document the occurrence of natural attenuation. Chlorinated hydrocarbon and biogeochemical data were used to develop a site-specific conceptual model where both anaerobic and aerobic biological processes are responsible for the destruction of PCE, TCE, and daughter metabolites. An examination of groundwater biogeochemical data showed a region of depleted dissolved oxygen with elevated dissolved methane and hydrogen concentrations. Reductive dechlorination likely dominated in the anaerobic portion of the aquifer where PCE and TCE levels were observed to decrease with a simultaneous increase in cis-1,2-dichloroethene (cis-DCE), vinyl chloride (VC), ethene, and dissolved chloride. Near the anaerobic/ aerobic interface, concentrations of cis-DCE and VC decreased to below detection limits, presumably due to aerobic biotransformation processes. Therefore, the contaminant and daughter product plumes present at the site appear to have been naturally atteuated by a combination of active anaerobic and aerobic biotransformation processes.

  3. Fate and Transport of Acrylamide in Soil and Groundwater Systems: Sorption, Retardation and Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Arrowood, T.; Young, M.; Yu, Z.; Labahn, S.; Moser, D.

    2007-12-01

    Acrylamide (AMD) is a known animal and suspected human carcinogen and is used to produce polyacrylamide (PAM), which has been proposed as a technology for seepage control in unlined water delivery canals. The fate and transport of AMD in groundwater systems is not well known, and previous studies have not quantified the sorption coefficient (Kd), sorption isotherms, or estimated AMD breakthrough and transport parameters in soil and water systems. In this study, batch experiments and repacked soil column tests were conducted on three soils (a control sand, and field collected sand and loam soils) to determine the Kd, retardation factor and the form of the sorption isotherm. A numerical model (HYDRUS 2D) was used to simulate a canal environment using the fate and transport parameters of AMD obtained in the laboratory. Microbial degradation rates, obtained from a companion study (Labahn et al. 2007) were used in the model. Photodegradation rates for AMD were also considered. Results from batch studies indicate a Freundlich-type sorption isotherm for AMD in the loam soil. Sorption in the sands was not significant. The preliminary results for the soil column tests show that AMD is conservative in all three types of soil tested with retardation (R) values ranging from 0.985-1.072, with most column studies showing 0.99groundwater showed significant impact of canal sealing and biodegradation, but little impact from the modest retardation rates and sorption obtained from the laboratory studies.

  4. SUBSURFACE SOIL CONDITIONS BENEATH AND NEAR BUILDINGS AND THE POTENTIAL EFFECTS ON SOIL VAPOR INTRUSION

    EPA Science Inventory

    Migration of volatile chemicals from the subsurface into overlying buildings is called vapor intrusion. Volatile organic chemicals in contaminated soils or groundwater can emit vapors that may migrate through subsurface soils and enter indoor air spaces of overlying buildings. T...

  5. Biosolids and distillery effluent amendment to Irish Miscanthus ×giganteus plantations: impacts on groundwater and soil.

    PubMed

    Galbally, P; Fagan, C; Ryan, D; Finnan, J; Grant, J; McDonnell, K

    2012-01-01

    It is necessary to determine the risk of water pollution arising from amendment of organic by-products (OBs) to energy crops under Irish conditions. Therefore, the impact of landspreading two OBs on the quality of groundwater underlying plantations of Miscanthus X giganteus was assessed. Municipal biosolids and distillery effluent (DE) were spread annually (for 4 yr) on six 0.117-ha treatment plots at rates of 100, 50, and 0%. The 100% rate represented a maximum P load of 15 t ha(-1) as per Irish EPA regulation. Groundwater was sampled for 25 mo and tested for pH, electrical conductivity, NO(3)(-), orthophosphate (PO(4)(3-)), total soluble P, K(+), Cu, Cd, Cr, Pb, Ni, and Zn. Assessment of quality was based on comparison with Irish groundwater threshold values (GTVs). The study was limited to within-plot using a "well bottom" approach and did not investigate movement of groundwater plumes or vectors of percolation through the soil profile. Mean groundwater concentrations did not exceed GTVs during the sampling period for any species, with the exception of groundwater PO(4)(3-) in the 100% DE plot, which was almost double the GTV of 0.035 mg L(-1). There was no significant build-up of nutrients or heavy metals in groundwater (or soil) for any plot. Excessive PO(4)(3-) in the 100% DE plot groundwater is likely due to high background soil P, soil characteristics, and the occurrence of macropore/soil pore flow. These factors (particularly background soil P) should be assessed when determining suitable sites for land-spreading OBs.

  6. Simulation of bioventing for soil and ground-water remediation

    SciTech Connect

    McClure, P.D.; Sleep, B.E.

    1996-11-01

    A three-dimensional finite difference model for simulation of bioventing is presented. The model incorporates three-phase (gas-water-organic) flow with equilibrium interphase mass transfer and dispersive transport of organic compounds, oxygen, and carbon dioxide. Growth of microorganisms, substrate and oxygen consumption, and carbon dioxide production due to microbial activity are included. Biodegradation limitations due to both substrate and oxygen availability are modeled using the dual Monod formulation. The model is applied to predict the fate of a spill of toluene in the vadose zone under natural conditions and with various configurations of air injection and vapor extraction wells. Configurations of wells are determined that maximize biodegradation and minimize both the amount of toluene withdrawn in extraction wells and the amount lost to the atmosphere.

  7. Hydrogeologic framework and ground-water resources at Seymour Johnson Air Force Base, North Carolina

    USGS Publications Warehouse

    Cardinell, A.P.; Howe, S.S.

    1997-01-01

    A preliminary hydrogeologic framework of the Seymour Johnson Air Force Base was constructed from published data, available well data, and reports from Air Base files, City of Goldsboro and Wayne County records, and North Carolina Geological Survey files. Borehole geophysical logs were run in selected wells; and the surficial, Black Creek, and upper Cape Fear aquifers were mapped. Results indicate that the surficial aquifer appears to have the greatest lateral variability of clay units and aquifer material of the three aquifers. A surficial aquifer water-level surface map, constructed from selected monitoring wells screened exclusively in the surficial aquifer, indicates the general direction of ground-water movement in this mostly unconfined aquifer is toward the Neuse River and Stoney Creek. However, water-level gradient data from a few sites in the surficial aquifer did not reflect this trend, and there are insufficient hydrologic and hydrogeologic data to determine the cause of these few anamalous measurements. The Black Creek aquifer underlies the surficial aquifer and is believed to underlie most of Wayne County, including the Air Base where the aquifer and overlying confining unit are estimated from well log data to be as much as 100 feet thick. The Black Creek confining unit ranges in thickness from less than 8 feet to more than 20 feet. There are currently no accessible wells screened exclusively in the Black Creek aquifer from which to measure water levels. The upper Cape Fear aquifer and confining unit are generally found at depths greater than 80 feet below land surface at the Air Base, and are estimated to be as much as 70 feet thick. Hydrologic and hydrogeologic data are insufficient to determine localized surficial aquifer hydrogeology, ground-water movement at several sites, or hydraulic head differences between the three aquifers.

  8. Greenhouse gas emission and groundwater pollution potential of soils amended with raw swine manure, dry and wet pyrolyzed swine biochars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research is to study the greenhouse gas emission and groundwater pollution potentials of the soils amended with raw swine solid and swine biochars made from different thermochemical conditions. Triplicate sets of small pots were designed: 1) control soil with a 50/50 mixture of...

  9. Factors controlling the concentration of methane and other volatiles in groundwater and soil-gas around a waste site

    NASA Astrophysics Data System (ADS)

    Barber, C.; Davis, G. B.; Briegel, D.; Ward, J. K.

    1990-01-01

    The concentration of methane in groundwater and soil-gas in the vicinity of a waste landfill on an unconfined sand aquifer has been investigated in detail. These data have been used to evaluate techniques which use volatile organic compounds in soil-gas as indicators of groundwater contamination. Simple one-dimensional models of gas advection and diffusion have been adapted for use in the study. Lateral advection of gas in the unsaturated sand was found to be seasonal and was most noticeable in winter when the profile was wet; a mean velocity of 1 m d - was measured from breakthrough of a helium tracer in an injection test. The effects of advection on trace concentrations of methane in soil-gas were limited to within 150-200m from the waste site and resulted from pressure gradients brought about by positive gas pressures in the landfill, and also as a result of ebullition (gas bubbling) from contaminated groundwater. The distribution of methane in soil-gas at shallow (2m) depth gave a general indication of the direction of movement of contaminants with groundwater in close proximity to the landfill. Outside this zone, diffusional transport of methane from groundwater to soil-gas occurred and methane in soil-gas sampled close to the water table was found to be a useful indicator of contaminated groundwater. Modelling the exchange of volatiles between aqueous and gas phases indicates that a wide range of organic compounds, particularly those with Henry's Law constants greater than 2.5 × 10 t-2 kPam 3mol -1, would have potential for use as indicators of pollution, if these were present in groundwater and they behaved relatively conservatively. In general, the principal factors controlling the concentration of these volatiles in soil-gas were the concentration gradient at the water table and capillary fringe and the ratio of diffusion coefficients in the saturated and unsaturated zones.

  10. Hydrogeology and simulation of ground-water flow at Dover Air Force Base, Delaware

    USGS Publications Warehouse

    Hinaman, Kurt C.; Tenbus, Frederick J.

    2000-01-01

    Dover Air Force Base in Kent County, Delaware, has many contaminated sites that are in active remediation. To assist in this remediation, a steady-state model of ground-water flow was developed to aid in understanding the hydrology of the system, and for use as a ground-watermanagement tool. This report describes the hydrology on which the model is based, a description of the model itself, and some applications of the model.Dover Air Force Base is underlain by unconsolidated sediments of the Atlantic Coastal Plain. The primary units that were investigated include the upper Calvert Formation and the overlying Columbia Formation. The uppermost sand unit in the Calvert Formation at Dover Air Force Base is the Frederica aquifer, which is the deepest unit investigated in this report. A confining unit of clayey silt in the upper Calvert Formation separates the Frederica aquifer from the lower surficial aquifer, which is the basal Columbia Formation. North and northwest of Dover Air Force Base, the Frederica aquifer subcrops beneath the Columbia Formation and the upper Calvert Formation confining unit is absent. The Calvert Formation dips to the southeast. The Columbia Formation consists predominately of sands, silts, and gravels, although in places there are clay layers that separate the surficial aquifer into an upper and lower surficial aquifer. The areal extent of these clay layers has been mapped by use of gamma logs. Long-term hydrographs reveal substantial changes in both seasonal and annual ground-water recharge. These variations in recharge are related to temporal changes in evaporation, transpiration, and precipitation. The hydrographs show areas where extensive silts and clays are present in the surficial aquifer. In these areas, the vertical gradient between water levels in wells screened above and below the clays can be as large as several feet, and local ground-water highs typically form during normal recharge conditions. When drought conditions persist

  11. Seasonal variation of polycyclic aromatic hydrocarbons in soil and air of Dalian areas, China: an assessment of soil-air exchange.

    PubMed

    Wang, Degao; Yang, Meng; Jia, Hongliang; Zhou, Lei; Li, Yifan

    2008-09-01

    The seasonal variations of concentrations of PAHs in the soil and the air were measured in urban and rural region of Dalian, China in 2007. In soil, mean concentrations of all PAHs in summer were larger than those in winter, whereas the concentrations of heavier weight PAHs in winter were larger than those in summer. Winter/summer concentration ratios for individual PAHs (R(W/S)) increased with the increase of molecular weight of PAHs in soil, indicating that PAHs with high molecular weight were more easily deposited to soil in winter than summer. In air, mean concentrations of all PAHs in winter were larger than those in summer. In comparison with the R(W/S) in soil, all the values of R(W/S) in air were larger than one indicating that the entire individual PAH concentrations in winter were larger than those in summer. The average concentration composition for each PAH compound in soil and air samples was determined and the seasonal change of PAH profile was very small. It was suggested that PAHs in soils and air had the same or similar sources both in winter and summer. The approach to the soil-air equilibrium was assessed by calculating fugacity quotients between soil and air using the soil and air concentrations. The calculated soil-air fugacity quotients indicated that soil acted as a secondary source to the atmosphere for all lighter weight PAHs (two-three rings) and it will continue to be a sink for heavier weight PAHs (five-six rings) in the Dalian environment, both in winter and summer. Medium weight PAHs (four-five rings) were close to the soil-air equilibrium and the tendency shifted between soil and air when season or function region changed. The fugacity quotients of PAHs in summer (mean temperature 298 K) were larger than those in winter (mean temperature 273 K), indicating a higher tendency in summer than winter for PAHs to move from soil to air. The variation of ambient conditions such as temperature, rainfall, etc. can influence the movement of PAHs

  12. Radon levels in groundwaters and natural radioactivity in soils of the volcanic region of La Garrotxa, Spain.

    PubMed

    Moreno, V; Bach, J; Baixeras, C; Font, Ll

    2014-02-01

    Groundwater radon level and soil radionuclide concentration have been measured in the volcanic region of La Garrotxa (Catalonia, Spain) to further research on the origin and dynamics of high radon levels over volcanic materials found in this region. Water samples from different aquifers have been collected from wells and springs and the water radon levels obtained have been lower than 30 Bq l(-1). Soil samples have been collected from different geological formations (volcanic and non-volcanic), being Quaternary sedimentary deposits those that have presented the highest mean values of (40)K, (226)Ra and (232)Th concentrations (448 ± 70 Bq kg(-1), 35 ± 5 Bq kg(-1) and 38 ± 5 Bq kg(-1), respectively). Additionally, indoor/outdoor terrestrial radiation absorbed dose rate in air have been measured to better characterize the region from the radiological point of view. Terrestrial radiation absorbed dose rates measurement points have been chosen on the basis of geological and demographical considerations and the results obtained, from 27 to 91 nGy h(-1), show a clear relation with geological formation materials. The highest terrestrial gamma absorbed dose rate is observed over Quaternary sedimentary deposits as well. All these results help to better understand previous surveys related with indoor and outdoor radon levels and to reinforce the hypotheses of a radon transport through the fissure network.

  13. Characterization and fingerprinting of soil and groundwater contamination sources around a fuel distribution station in Galicia (NW Spain).

    PubMed

    Balseiro-Romero, María; Macías, Felipe; Monterroso, Carmen

    2016-05-01

    Soil and groundwater contamination around a fuel distribution station in Tomiño (NW Spain) was evaluated. For this purpose, top and subsoil (up to 6.4 m) and groundwater were sampled around the station, approximately in a 60-m radius. Samples were analysed by HS-SPME-GC-MS to identify and quantify volatile fuel organic compounds (VFOC) (MTBE, ETBE and BTEX) and diesel range organics (DRO). Analysis and fingerprinting data suggested that the contamination of soil and groundwater was provoked by a fuel leak from underground storage tanks. This was reflected by hydrocarbon indices and principal component analysis, which discriminated a direct source of contamination of the subsoil samples around the station. The contaminants probably migrated from tank nearby soils to surrounding soils and leached to groundwater, following a SW direction. Irrigation with contaminated groundwater provoked a severe contamination of topsoils, which were enriched with the lightest components of gasoline and diesel. Fingerprinting also revealed the continuity of the leak, reflected by the presence of volatiles in some samples, which principally appeared in fresh leaks. MTBE was detected in a very high concentration in groundwater samples (up to 690 μg L(-1)), but it was not detected in fresh gasoline. This also evidenced an old source of contamination, probably starting in the mid-1990s, when the use of MTBE in gasoline was regulated.

  14. Mercury speciation analyses in HgCl(2)-contaminated soils and groundwater--implications for risk assessment and remediation strategies.

    PubMed

    Bollen, A; Wenke, A; Biester, H

    2008-01-01

    Since the 19th century, mercury(II)chloride (HgCl(2)) has been used on wood impregnation sites to prevent wooden poles from decay, leaving behind a legacy of highly contaminated soil/aquifer systems. Little is known about species transformation and mobility of HgCl(2) in contaminated soils and groundwater. At such a site the behaviour of HgCl(2) in soils and groundwater was investigated to assist in risk assessment and remediation. The soil is low in organic carbon and contains up to 11,000 mg Hg/kg. Mercury (Hg) concentrations in groundwater decrease from 230 to 0.5 microg/l within a distance of 1.3 km. Hg species transformations in soil and aqueous samples were analysed by means of solid-phase Hg pyrolysis and CV-AAS. In aqueous samples, Hg species were distinguished between ionic/reactive Hg and complex-bound Hg. Potential mobility of Hg in soils was studied through batch experiments. Most Hg in the soil is matrix-bound HgCl(2), whereas in the aquifer secondary formation to Hg(0) could be observed. Aqueous Hg speciation in groundwater and soil solutions shows that an average of 84% of soluble Hg exists as easily reducible, inorganic Hg species (mostly HgCl(2)). The proportion of complex-bound Hg increases with distance due to the transformation of inorganic HgCl(2). The frequent occurrence of Hg(0) in the aquifer suggests the formation and degassing of Hg(0), which is, in addition to dilution, an important process, lowering Hg concentrations in the groundwater. High percentage of mobile Hg (3-26%) and low seepage fluxes will result in continuous Hg release over centuries requiring long-term groundwater remediation. Results of soluble Hg speciation suggest that filtering materials should be adapted to ionic Hg species, e.g. specific resins or amalgamating metal alloys.

  15. Evaluation of Trichloroethylene vapour fluxes using measurements at the soil-air interface and in the atmosphere close to the soil surface

    NASA Astrophysics Data System (ADS)

    Cotel, Solenn; Nagel, Vincent; Schäfer, Gerhard; Marzougui, Salsabil; Razakarisoa, Olivier; Millet, Maurice

    2013-04-01

    Industrialization during the 19th and 20th century led to the use of chemical products such as chlorinated solvents, e.g., trichloroethylene (TCE). At locations where volatile organic compounds were accidentally spilled on the soil during transport or leaked from their storage places, they could have migrated vertically through the unsaturated zone towards the underlying groundwater. As a result of their high volatility a large vapour plume is consequently formed. Understanding when, at which concentrations and how long, these pollutants will be present in soil, groundwater, atmosphere or indoor air, still remains a challenge up to date. This study was conducted as part of a broader experiment of TCE multiphase mass transfer in a large (25m×12m×3m) well-instrumented artificial basin. TCE was injected as liquid phase in the vadose zone and experiments were conducted during several months. Firstly, TCE vapour fluxes were experimentally determined in two different ways: (a) direct measurements at the soil-air interface using a flux chamber and (b) evaluations based on measurements of TCE concentrations in the air above the soil surface using a modular experimental flume (5m×1m×1m) with a fixed air flow. Secondly, numerical simulations were conducted to analyse the differences between these two types of fluxes. Several positions of the flume on the soil surface were tested. Based on the TCE concentrations measured in the air, vapour fluxes were determined with the aerodynamic method using the modified Thornthwaite-Holzmann equation. It assumes that the concentrations and velocities are temporally and spatially constant in horizontal planes and requires data on the gradients of concentration, horizontal wind velocity and temperature. TCE vapour fluxes measured at the soil-air interface decrease with distance from the source zone. However, this decrease was either high, at the first stage of experiment (120μg/(m2s) near the source zone compared to 1,1μg/(m2s) 2m

  16. Assessment of metal contamination in groundwater and soils in the Ahangaran mining district, west of Iran.

    PubMed

    Mehrabi, Behzad; Mehrabani, Shiva; Rafiei, Behrouz; Yaghoubi, Behrouz

    2015-12-01

    In this study, 28 groundwater and 13 soil samples from Ahangaran mining district in Hamedan Province, west of Iran were collected to evaluate the level of contamination. Average concentrations of As, Cu, Pb, Zn, Mn, Sb, and Ni in groundwater samples were 1.39, 3.73, 2.18, 9.37, 2.35, 4.44, and 5.50 μg/L (wet season), and 11.64, 4.92, 4.32, 14.77, 5.43, 4.12, and 0.98 μg/L (dry season), respectively. Results of groundwater samples analysis showed that the average of analyzed metals in the wet and dry seasons were below the permissible limits, except As in the dry season which displays concentrations that exceed US EPA water quality criteria recommended for drinking water. Also, the heavy metal pollution index (HPI) values in each sampling station were less than the critical index limit and were suitable for drinking. Factor analysis revealed that variables influential to groundwater quality in one season may not be as important in another season. Average concentrations of Ag, As, Cd, Cu, Pb, Sb, and Zn in soil samples were 2.61, 31.44, 0.51, 55.90, 1284.9, 21.26, and 156.04 mg kg(-1), respectively. The results of the geoaccumulation index (I geo) showed the following decreasing order: Pb > Zn > Cu > As > Sb > Cd > Ag. Potential ecological risk index (RI) suggests that the contamination in the investigated area is moderate to very high risk and the ranking of the contaminants in decreasing order is Ag > Sb > Pb > Cd > As > Cu > Zn.

  17. Thermoelectric Air/Soil Energy-Harvesting Device

    NASA Technical Reports Server (NTRS)

    Snyder, Jeffrey; Fleurial, Jean-Pierre; Lawrence, Eric

    2005-01-01

    A proposed thermoelectric device would exploit natural temperature differences between air and soil to harvest small amounts of electric energy. Because the air/soil temperature difference fluctuates between nighttime and daytime, it is almost never zero, and so there is almost always some energy available for harvesting. Unlike photovoltaic cells, the proposed device could operate in the absence of sunlight. Unlike a Stirling engine, which could be designed to extract energy from the air/soil temperature difference, the proposed device would contain no moving parts. The main attractive feature of the proposed device would be high reliability. In a typical application, this device would be used for low-power charging of a battery that would, in turn, supply high power at brief, infrequent intervals for operating an instrumentation package containing sensors and communication circuits. The device (see figure) would include a heat exchanger buried in soil and connected to a heat pipe extending up to a short distance above the ground surface. A thermoelectric microgenerator (TEMG) would be mounted on top of the heat pipe. The TEMG could be of an advanced type, now under development, that could maintain high (relative to prior thermoelectric generators) power densities at small temperature differentials. A heat exchanger exposed to the air would be mounted on top of the TEMG. It would not matter whether the air was warmer than the soil or the soil warmer than the air: as long as there was a nonzero temperature difference, heat would flow through the device and electricity would be generated. A study of factors that could affect the design and operation of the device has been performed. These factors include the thermal conductances of the soil, the components of the device, the contacts between the components of the device, and the interfaces between the heat exchangers and their environments. The study included experiments that were performed on a model of the device

  18. Application of iron sulfide particles for groundwater and soil remediation: A review.

    PubMed

    Gong, Yanyan; Tang, Jingchun; Zhao, Dongye

    2016-02-01

    Rapid industrialization and urbanization have resulted in elevated concentrations of hazardous inorganic and organic contaminants in groundwater and soil, which has become a paramount concern to the environment and the public health. In recent years, iron sulfide (FeS), a major constituent of acid-volatile sulfides, has elicited extensive interests in environmental remediation due to its ubiquitous presence and high treatment efficiency in anoxic environment. This paper provides a comprehensive review on recent advances in: (1) synthesis of FeS particles (including nanoscale FeS); and (2) reactivity of FeS towards a variety of common environmental contaminants in groundwater and soil over extended periods of time, namely, heavy metals (Hg(II), Cu(II), Pb(II), and Cr(VI)), oxyanions (arsenite, arsenate, selenite, and selenate), radionuclides (e.g., uranium (U) and neptunium (Np)), chlorinated organic compounds (e.g., trichloroethane, trichloroethylene, and p-chloroaniline), nitroaromatic compounds, and polychlorinated biphenyls. Different physiochemical and biological methods for preparing FeS with desired particle size, structure, and surface properties are discussed. Reaction principles and removal effectiveness/constraints are discussed in details. Special attention is placed to the application of nanoscale FeS particles because of their unique properties, such as small particle size, large specific surface area, high surface reactivity, and soil deliverability in the subsurface. Moreover, current knowledge gaps and further research needs are identified. PMID:26707732

  19. Bisphenol A, nonylphenols, benzophenones, and benzotriazoles in soils, groundwater, surface water, sediments, and food: a review.

    PubMed

    Careghini, Alessando; Mastorgio, Andrea Filippo; Saponaro, Sabrina; Sezenna, Elena

    2015-04-01

    Contaminants of emerging concern (CECs) are not commonly monitored in the environment, but they can enter the environment from a variety of sources. The most worrying consequence of their wide use and environmental diffusion is the increase in the possible exposure pathways for humans. Moreover, knowledge of their behavior in the environment, toxicity, and biological effects is limited or not available for most CECs. The aim of this work is to edit the state of the art on few selected CECs having the potential to enter the soil and aquatic systems and cause adverse effects in humans, wildlife, and the environment: bisphenol A (BPA), nonylphenol (NP), benzophenones (BPs), and benzotriazole (BT). Some reviews are already available on BPA and NP, reporting about their behavior in surface water and sediments, but scarce and scattered information is available about their presence in soil and groundwater. Only a few studies are available about BPs and BT in the environment, in particular in soil and groundwater. This work summarizes the information available in the literature about the incidence and behavior of these compounds in the different environmental matrices and food. In particular, the review focuses on the physical-chemical properties, the environmental fate, the major degradation byproducts, and the environmental evidence of the selected CECs.

  20. Application of iron sulfide particles for groundwater and soil remediation: A review.

    PubMed

    Gong, Yanyan; Tang, Jingchun; Zhao, Dongye

    2016-02-01

    Rapid industrialization and urbanization have resulted in elevated concentrations of hazardous inorganic and organic contaminants in groundwater and soil, which has become a paramount concern to the environment and the public health. In recent years, iron sulfide (FeS), a major constituent of acid-volatile sulfides, has elicited extensive interests in environmental remediation due to its ubiquitous presence and high treatment efficiency in anoxic environment. This paper provides a comprehensive review on recent advances in: (1) synthesis of FeS particles (including nanoscale FeS); and (2) reactivity of FeS towards a variety of common environmental contaminants in groundwater and soil over extended periods of time, namely, heavy metals (Hg(II), Cu(II), Pb(II), and Cr(VI)), oxyanions (arsenite, arsenate, selenite, and selenate), radionuclides (e.g., uranium (U) and neptunium (Np)), chlorinated organic compounds (e.g., trichloroethane, trichloroethylene, and p-chloroaniline), nitroaromatic compounds, and polychlorinated biphenyls. Different physiochemical and biological methods for preparing FeS with desired particle size, structure, and surface properties are discussed. Reaction principles and removal effectiveness/constraints are discussed in details. Special attention is placed to the application of nanoscale FeS particles because of their unique properties, such as small particle size, large specific surface area, high surface reactivity, and soil deliverability in the subsurface. Moreover, current knowledge gaps and further research needs are identified.

  1. Field controlled experiments of mercury accumulation in crops from air and soil.

    PubMed

    Niu, Zhenchuan; Zhang, Xiaoshan; Wang, Zhangwei; Ci, Zhijia

    2011-10-01

    Field open top chambers (OTCs) and soil mercury (Hg) enriched experiments were employed to study the influence of Hg concentrations in air and soil on the Hg accumulation in the organs of maize (Zea mays L.) and wheat (Triticum aestivum L.). Results showed that Hg concentrations in foliages were correlated significantly (p < 0.05) with air Hg concentrations but insignificantly correlated with soil Hg concentrations, indicating that Hg in crop foliages was mainly from air. Hg concentrations in roots were generally correlated with soil Hg concentrations (p < 0.05) but insignificantly correlated with air Hg concentrations, indicating that Hg in crop roots was mainly from soil. No significant correlations were found between Hg concentrations in stems and those in air and soil. However, Hg concentrations in upper stems were usually higher than those in bottom stems, implying air Hg might have stronger influence than soil Hg on stem Hg accumulation.

  2. Radioactivity in rocks and soil and interaction with groundwater in an arid region

    NASA Astrophysics Data System (ADS)

    Alshamsi, Dalal; Murad, Ahmed; Aldahan, Ala; Hou, Xiaolin; El Saiy, Ayman

    2014-05-01

    Interaction of groundwater with soil and rocks changes the chemical composition of the water both spatially and temporally. In arid regions, surficial recharge of groundwater is generally limited to sporadic rainfall events which may cause rapid interaction between the recharge water and the aquifers materials. Among the elements that commonly increase in concentration as groundwater interact with the aquifer materials are the radioactive elements such as uranium and thorium and their decay chain products. Here, we present data on 235U, 238U, 232Th as well as 137Cs in some sediments and rock aquifers located in the United Arab Emirates (UAE) in southeastern Arabian Peninsula. The Quaternary sediments are composed of silt, sand and gravel with varying proportions of quartz, carbonates, feldspars, evaporites, while the carbonates are mainly limestones, dolomitic limestones, dolomite and calcareous mudstones. These carbonate rocks cover ages extending from 10-230 Myr. After complete digestion using fluoric and nitric acids and chemical separation, the isotopes were measured using ICP-MS. The 235U, 238U and 232Th concentrations ranges are 2.66-32.5 ng/g, 354.7-4453 ng/g and 13.2-1367 ng/g respectively in the carbonate rocks. In the sediments the concentrations are 4.6-17.5 ng/g for 235U, 631.7-2406 ng/g for 238U and 25.6-799.6 ng/g for 232Th. Although it is difficult to quantify the amounts of uranium isotopes that enter the hydrological system from the aquifers, it seems that in the presence of carboxyl ions, uranium forms highly soluble complexes which can be transported to large distances in groundwater. The variations in 232Th concentrations are probably controlled by the availability of sulfate salt rocks (like gypsum) interacting with thorium and forming soluble thorium compounds which can also explain the highly variable concentrations in groundwater.

  3. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region

    PubMed Central

    Oikawa, P. Y.; Ge, C.; Wang, J.; Eberwein, J. R.; Liang, L. L.; Allsman, L. A.; Grantz, D. A.; Jenerette, G. D.

    2015-01-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

  4. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region.

    PubMed

    Oikawa, P Y; Ge, C; Wang, J; Eberwein, J R; Liang, L L; Allsman, L A; Grantz, D A; Jenerette, G D

    2015-01-01

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality. PMID:26556236

  5. Unusually high soil nitrogen oxide emissions influence air quality in a high-temperature agricultural region.

    PubMed

    Oikawa, P Y; Ge, C; Wang, J; Eberwein, J R; Liang, L L; Allsman, L A; Grantz, D A; Jenerette, G D

    2015-11-10

    Fertilized soils have large potential for production of soil nitrogen oxide (NOx=NO+NO2), however these emissions are difficult to predict in high-temperature environments. Understanding these emissions may improve air quality modelling as NOx contributes to formation of tropospheric ozone (O3), a powerful air pollutant. Here we identify the environmental and management factors that regulate soil NOx emissions in a high-temperature agricultural region of California. We also investigate whether soil NOx emissions are capable of influencing regional air quality. We report some of the highest soil NOx emissions ever observed. Emissions vary nonlinearly with fertilization, temperature and soil moisture. We find that a regional air chemistry model often underestimates soil NOx emissions and NOx at the surface and in the troposphere. Adjusting the model to match NOx observations leads to elevated tropospheric O3. Our results suggest management can greatly reduce soil NOx emissions, thereby improving air quality.

  6. Experimental and numerical investigations of soil water balance at the hinterland of the Badain Jaran Desert for groundwater recharge estimation

    NASA Astrophysics Data System (ADS)

    Hou, Lizhu; Wang, Xu-Sheng; Hu, Bill X.; Shang, Jie; Wan, Li

    2016-09-01

    Quantification of groundwater recharge from precipitation in the huge sand dunes is an issue in accounting for regional water balance in the Badain Jaran Desert (BJD) where about 100 lakes exist between dunes. In this study, field observations were conducted on a sand dune near a large saline lake in the BJD to investigate soil water movement through a thick vadose zone for groundwater estimation. The hydraulic properties of the soils at the site were determined using in situ experiments and laboratory measurements. A HYDRUS-1D model was built up for simulating the coupling processes of vertical water-vapor movement and heat transport in the desert soil. The model was well calibrated and validated using the site measurements of the soil water and temperature at various depths. Then, the model was applied to simulate the vertical flow across a 3-m-depth soil during a 53-year period under variable climate conditions. The simulated flow rate at the depth is an approximate estimation of groundwater recharge from the precipitation in the desert. It was found that the annual groundwater recharge would be 11-30 mm during 1983-2012, while the annual precipitation varied from 68 to 172 mm in the same period. The recharge rates are significantly higher than those estimated from the previous studies using chemical information. The modeling results highlight the role of the local precipitation as an essential source of groundwater in the BJD.

  7. Effect of Harsh or Mild Extraction of Soil on Pesticide Leaching to Groundwater.

    PubMed

    Boesten, Jos J T I

    2016-07-01

    Assessment of leaching to groundwater is an important aspect of pesticide risk assessment. The first leaching tier usually consists of simulations with leaching scenarios based on pesticide-soil properties derived from laboratory studies. Because the extractability of pesticide residues in such studies decreases with time, the harshness of the extraction method influences these pesticide-soil properties. This study investigates the effect of using a mild or harsh extraction method on simulated leaching to groundwater with consideration of substances with a range of half-lives and organic matter sorption coefficient values for selected leaching scenarios. The model for linking the concentrations of the mild and the harsh systems was based on laboratory studies with two pesticides and a Dutch sandy soil and was tested against Canadian field studies with atrazine (6-chloro-2-ethyl-4-isopropyl-1,3,5-triazine-2,4-diamine). The degradation rate and the aged-sorption parameters of each "mild" soil-substance system were derived from a hypothetical laboratory incubation study using prescribed parameter values for the corresponding "harsh" soil-substance system. Simulations were performed for three European leaching scenarios (United Kingdom, France, Portugal). For the best-guess parameter set, the leaching concentrations of the harsh system were approximately equal to those of the mild system at leaching concentrations greater than 1 μg L and were at most approximately a factor of two higher than those of the mild systems at mild leaching concentrations between 0.01 and 0.1 μg L. However, an extreme parameter set led to harsh leaching concentrations that were at most approximately 10 times higher than the mild leaching concentrations at levels between 0.01 and 0.1 μg L. PMID:27380081

  8. Groundwater influence on soil moisture memory, ET fluxes and the seasonal cycle of streamflow in the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Martinez-de la Torre, Alberto; Miguez-Macho, Gonzalo

    2014-05-01

    In this work we investigate the memory induced in soil moisture fields by groundwater long timescales of variation in the Iberian Peninsula with the LEAFHYDRO soil-vegetation-hydrology model, which includes a fully coupled water table to soil moisture and river flow via 2-way fluxes. We select a 10-year period (1989-2000) with transitions from wet to dry to again wet long lasting conditions and we carry out simulations at 2.5 km spatial resolution forced by ERA-Interim and a high-resolution precipitation analysis over Spain and Portugal. The model produces a realistic water table that we validate with hundreds of time series (ranging from 4 to 10 years) of observations over the Iberian Peninsula. Modeled river flow is also compared to observations. Over shallow water table regions, results highlight the groundwater buffering effect on soil moisture fields over dry spells and long-term droughts, as well as the slow recovery of pre-drought soil wetness once climatic conditions turn wetter. Groundwater sustains river flow during the dry summers and in turn, particularly in the south of Spain where the summer drought is more pronounced, river seepage feeds groundwater in wide valleys, keeping the water table shallow. The longer lasting wet conditions in the soil when groundwater is considered increases ET, especially in the summer, when it is mostly water-limited. Our results suggest that groundwater interaction with soil moisture should be considered for climate seasonal forecasting and climate studies in general over water-limited regions where shallow water tables are significantly present.

  9. Engineered passive bioreactive barriers: risk-managing the legacy of industrial soil and groundwater pollution.

    PubMed

    Kalin, Robert M

    2004-06-01

    Permeable reactive barriers are a technology that is one decade old, with most full-scale applications based on abiotic mechanisms. Though there is extensive literature on engineered bioreactors, natural biodegradation potential, and in situ remediation, it is only recently that engineered passive bioreactive barrier technology is being considered at the commercial scale to manage contaminated soil and groundwater risks. Recent full-scale studies are providing the scientific confidence in our understanding of coupled microbial (and genetic), hydrogeologic, and geochemical processes in this approach and have highlighted the need to further integrate engineering and science tools.

  10. Conducting subsurface soil and groundwater radiological investigations: a case study from the University of Rochester.

    PubMed

    Karam, P A

    2001-08-01

    The University of Rochester performed subsurface soil and groundwater radiological assessments in the vicinity of a research building to investigate for contamination from possible past releases of licensed radioactive materials. During the course of this investigation, our contractors developed candidate well drilling and sampling plans. The University of Rochester selected one of these plans, which was subsequently modified due to unexpected costs associated with the local geology. This paper describes the factors that were considered during the development and implementation of the drilling and sampling plan, as well as other considerations and concepts that are inherent in many environmental investigations.

  11. Simulation of future groundwater recharge using a climate model ensemble and SAR-image based soil parameter distributions - A case study in an intensively-used Mediterranean catchment.

    PubMed

    Herrmann, Frank; Baghdadi, Nicolas; Blaschek, Michael; Deidda, Roberto; Duttmann, Rainer; La Jeunesse, Isabelle; Sellami, Haykel; Vereecken, Harry; Wendland, Frank

    2016-02-01

    We used observed climate data, an ensemble of four GCM-RCM combinations (global and regional climate models) and the water balance model mGROWA to estimate present and future groundwater recharge for the intensively-used Thau lagoon catchment in southern France. In addition to a highly resolved soil map, soil moisture distributions obtained from SAR-images (Synthetic Aperture Radar) were used to derive the spatial distribution of soil parameters covering the full simulation domain. Doing so helped us to assess the impact of different soil parameter sources on the modelled groundwater recharge levels. Groundwater recharge was simulated in monthly time steps using the ensemble approach and analysed in its spatial and temporal variability. The soil parameters originating from both sources led to very similar groundwater recharge rates, proving that soil parameters derived from SAR images may replace traditionally used soil maps in regions where soil maps are sparse or missing. Additionally, we showed that the variance in different GCM-RCMs influences the projected magnitude of future groundwater recharge change significantly more than the variance in the soil parameter distributions derived from the two different sources. For the period between 1950 and 2100, climate change impacts based on the climate model ensemble indicated that overall groundwater recharge will possibly show a low to moderate decrease in the Thau catchment. However, as no clear trend resulted from the ensemble simulations, reliable recommendations for adapting the regional groundwater management to changed available groundwater volumes could not be derived.

  12. Simulation of future groundwater recharge using a climate model ensemble and SAR-image based soil parameter distributions - A case study in an intensively-used Mediterranean catchment.

    PubMed

    Herrmann, Frank; Baghdadi, Nicolas; Blaschek, Michael; Deidda, Roberto; Duttmann, Rainer; La Jeunesse, Isabelle; Sellami, Haykel; Vereecken, Harry; Wendland, Frank

    2016-02-01

    We used observed climate data, an ensemble of four GCM-RCM combinations (global and regional climate models) and the water balance model mGROWA to estimate present and future groundwater recharge for the intensively-used Thau lagoon catchment in southern France. In addition to a highly resolved soil map, soil moisture distributions obtained from SAR-images (Synthetic Aperture Radar) were used to derive the spatial distribution of soil parameters covering the full simulation domain. Doing so helped us to assess the impact of different soil parameter sources on the modelled groundwater recharge levels. Groundwater recharge was simulated in monthly time steps using the ensemble approach and analysed in its spatial and temporal variability. The soil parameters originating from both sources led to very similar groundwater recharge rates, proving that soil parameters derived from SAR images may replace traditionally used soil maps in regions where soil maps are sparse or missing. Additionally, we showed that the variance in different GCM-RCMs influences the projected magnitude of future groundwater recharge change significantly more than the variance in the soil parameter distributions derived from the two different sources. For the period between 1950 and 2100, climate change impacts based on the climate model ensemble indicated that overall groundwater recharge will possibly show a low to moderate decrease in the Thau catchment. However, as no clear trend resulted from the ensemble simulations, reliable recommendations for adapting the regional groundwater management to changed available groundwater volumes could not be derived. PMID:26190446

  13. Ground-water conditions at Beale Air Force Base and vicinity, California

    USGS Publications Warehouse

    Page, R.W.

    1980-01-01

    Ground-water conditions were studied in a 168-square-mile area between the Sierra Nevada and the Feather River in Yuba County, Calif. The area is in the eastern part of the Sacramento Valley and includes most of Beale Air Force Base. Source, occurrence, movement, and chemical quality of the ground water were evaluated. Ground water occurs in sedimentary and volcanic rocks of Tertiary and Quaternary age. The base of the freshwater is in the undifferentiated sedimentary rocks of Oligocene and Eocene age, that contain water of high dissolved-solids concentration. The ground water occurs under unconfined and partly confined conditions. At Beale Air Force Base it is at times partly confined. Recharge is principally from the rivers. Pumpage in the study area was estimated to be 129,000 acre-feet in 1975. In the 1960's, water levels in most parts of the study area declined less rapidly than in earlier years or became fairly stable. In the 1970's, water levels at Beale Air Force Base declined only slightly. Spacing of wells on the base and rates of pumping are such that excessive pumping interference is avoided. Water quality at the base and throughout the study area is generally good. Dissolved-solids concentrations are 700 to 900 milligrams per liter in the undifferentiated sedimentary rocks beneath the base well field. (USGS)

  14. Measurements of HFC-134a and HCFC-22 in groundwater and unsaturated-zone air: implications for HFCs and HCFCs as dating tracers

    USGS Publications Warehouse

    Haase, Karl B.; Busenberg, Eurybiades; Plummer, L. Niel; Casile, Gerolamo; Sanford, Ward E.

    2014-01-01

    A new analytical method using gas chromatography with an atomic emission detector (GC–AED) was developed for measurement of ambient concentrations of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) in soil, air, and groundwater, with the goal of determining their utility as groundwater age tracers. The analytical detection limits of HCFC-22 (difluorochloromethane, CHClF2) and HFC-134a (1,2,2,2-tetrafluoroethane, C2H2F4) in 1 L groundwater samples are 4.3 × 10− 1 and 2.1 × 10− 1 pmol kg− 1, respectively, corresponding to equilibrium gas-phase mixing ratios of approximately 5–6 parts per trillion by volume (pptv). Under optimal conditions, post-1960 (HCFC-22) and post-1995 (HFC-134a) recharge could be identified using these tracers in stable, unmixed groundwater samples. Ambient concentrations of HCFC-22 and HFC-134a were measured in 50 groundwater samples from 27 locations in northern and western parts of Virginia, Tennessee, and North Carolina (USA), and 3 unsaturated-zone profiles were collected in northern Virginia. Mixing ratios of both HCFC-22 and HFC-134a decrease with depth in unsaturated-zone gas profiles with an accompanying increase in CO2 and loss of O2. Apparently, ambient concentrations of HCFC-22 and HFC-134a are readily consumed by methanotrophic bacteria under aerobic conditions in the unsaturated zone. The results of this study indicate that soils are a sink for these two greenhouse gases. These observations contradict the previously reported results from microcosm experiments that found that degradation was limited above-ambient HFC-134a. The groundwater HFC and HCFC concentrations were compared with concentrations of chlorofluorocarbons (CFCs, CFC-11, CFC-12, CFC-113) and sulfur hexafluoride (SF6). Nearly all samples had measured HCFC-22 or HFC-134a that were below concentrations predicted by the CFCs and SF6, with many samples showing a complete loss of HCFC-22 and HFC-134a. This study indicates that HCFC-22 and HFC-134

  15. Nitrate in groundwater of the midwestern United States: A regional investigation on relations to land use and soil properties

    USGS Publications Warehouse

    Kolpin, D.; Burkart, M.; Goolsby, D.

    1999-01-01

    The intense application of nitrogen-fertilizer to cropland in the midwestern United States has created concern about nitrate contamination of the region's aquifers. Since 1991, the US Geological Survey has used a network of 303 wells to investigate the regional distribution of nitrate in near-surface aquifers of the midwestern United States. Detailed land use and soil data were compiled within a 2 km radius of 100 unconsolidated wells in the regional network to determine relations to nitrate concentrations in groundwater. For land use, the amount of irrigated land was directly related to nitrate concentrations in groundwater. For soils, the general water table depth and soil factors associated with rates of water movement were directly related to nitrate concentrations in groundwater.

  16. Incidence of metal and antibiotic resistance in Pseudomonas spp. from the river water, agricultural soil irrigated with wastewater and groundwater.

    PubMed

    Malik, Abdul; Aleem, Asma

    2011-07-01

    A total of 144 isolates of Pseudomonas spp. (48 each from the Yamuna River water, wastewater irrigated soil and groundwater irrigated soil) were tested for their resistance against certain heavy metals and antibiotics. Minimum inhibitory concentrations (MICs) of Hg(2+ ), Cd(2+ ), Cu(2+ ), Zn(2+ ), Ni(2+ ), Pb(2+ ), Cr(3+ ) and Cr(6+ ) for each isolate were also determined. A maximum MIC of 200 μg/ml for mercury and 3,200 μg/ml for other metals were observed. The incidences of metal resistance and MICs of metals for Pseudomonas isolates from the Yamuna water and wastewater irrigated soil were significantly different to those of groundwater irrigated soil. A high level of resistance against tetracycline and polymyxin B (81.2%) was observed in river water isolates. However, 87.5% of Pseudomonas isolates from soil irrigated with wastewater showed resistance to sulphadiazine, whereas 79.1% were resistant to both ampicillin and erythromycin. Isolates from soil irrigated with groundwater exhibited less resistance towards heavy metals and antibiotics as compared to those of river water and wastewater irrigated soil. Majority of the Pseudomonas isolates from water and soil exhibited resistance to multiple metals and antibiotics. Resistance was transferable to recipient Escherichia coli AB2200 strains by conjugation. Plasmids were cured with the curing agent ethidium bromide and acridine orange at sub-MIC concentration. PMID:20853188

  17. Incidence of metal and antibiotic resistance in Pseudomonas spp. from the river water, agricultural soil irrigated with wastewater and groundwater.

    PubMed

    Malik, Abdul; Aleem, Asma

    2011-07-01

    A total of 144 isolates of Pseudomonas spp. (48 each from the Yamuna River water, wastewater irrigated soil and groundwater irrigated soil) were tested for their resistance against certain heavy metals and antibiotics. Minimum inhibitory concentrations (MICs) of Hg(2+ ), Cd(2+ ), Cu(2+ ), Zn(2+ ), Ni(2+ ), Pb(2+ ), Cr(3+ ) and Cr(6+ ) for each isolate were also determined. A maximum MIC of 200 μg/ml for mercury and 3,200 μg/ml for other metals were observed. The incidences of metal resistance and MICs of metals for Pseudomonas isolates from the Yamuna water and wastewater irrigated soil were significantly different to those of groundwater irrigated soil. A high level of resistance against tetracycline and polymyxin B (81.2%) was observed in river water isolates. However, 87.5% of Pseudomonas isolates from soil irrigated with wastewater showed resistance to sulphadiazine, whereas 79.1% were resistant to both ampicillin and erythromycin. Isolates from soil irrigated with groundwater exhibited less resistance towards heavy metals and antibiotics as compared to those of river water and wastewater irrigated soil. Majority of the Pseudomonas isolates from water and soil exhibited resistance to multiple metals and antibiotics. Resistance was transferable to recipient Escherichia coli AB2200 strains by conjugation. Plasmids were cured with the curing agent ethidium bromide and acridine orange at sub-MIC concentration.

  18. Promising approaches to the purification of soils and groundwater from hydrocarbons (A Review)

    NASA Astrophysics Data System (ADS)

    Vodyanitskii, Yu. N.; Trofimov, S. Ya.; Shoba, S. A.

    2016-06-01

    Soils and waters are affected by oil spills in the course of oil production and hydrocarbon leakages because of the corrosion of underground reservoirs, as well as the filtration of hydrocarbons from the tailing ponds formed during the extraction of oil from oil sands. The conventional technology for the withdrawal of contaminated water and its purification on the surface is low-efficient and expensive. New approaches are proposed for the in situ purification of soils and groundwater. To accelerate the oxidation, active substances atypical for the supergenesis zone are used: peroxides of metals and hydrogen. The efficiency of hydrogen peroxide significantly increases when the oxidation is catalyzed by Fe2+ or Fe3+ (Fenton reaction). The effects of Fe(III), sulfates, and carbon dioxide as electron acceptors are studied under anaerobic conditions (with oxygen deficit).

  19. Impact of Climate Change on Soil and Groundwater Chemistry Subject to Process Waste Land Application

    NASA Astrophysics Data System (ADS)

    McNab, W. W.

    2013-12-01

    Nonhazardous aqueous process waste streams from food and beverage industry operations are often discharged via managed land application in a manner designed to minimize impacts to underlying groundwater. Process waste streams are typically characterized by elevated concentrations of solutes such as ammonium, organic nitrogen, potassium, sodium, and organic acids. Land application involves the mixing of process waste streams with irrigation water which is subsequently applied to crops. The combination of evapotranspiration and crop salt uptake reduces the downward mass fluxes of percolation water and salts. By carefully managing application schedules in the context of annual climatological cycles, growing seasons, and process requirements, potential adverse environmental impacts to groundwater can be mitigated. However, climate change poses challenges to future process waste land application efforts because the key factors that determine loading rates - temperature, evapotranspiration, seasonal changes in the quality and quantity of applied water, and various crop factors - are all likely to deviate from current averages. To assess the potential impact of future climate change on the practice of land application, coupled process modeling entailing transient unsaturated fluid flow, evapotranspiration, crop salt uptake, and multispecies reactive chemical transport was used to predict changes in salt loading if current practices are maintained in a warmer, drier setting. As a first step, a coupled process model (Hydrus-1D, combined with PHREEQC) was calibrated to existing data sets which summarize land application loading rates, soil water chemistry, and crop salt uptake for land disposal of process wastes from a food industry facility in the northern San Joaquin Valley of California. Model results quantify, for example, the impacts of evapotranspiration on both fluid flow and soil water chemistry at shallow depths, with secondary effects including carbonate mineral

  20. Ground-water data, 1969-77, Vandenberg Air Force Base area, Santa Barbara County, California

    USGS Publications Warehouse

    Lamb, Charles E.

    1980-01-01

    The water supply for Vandenberg Air Force Base is obtained from wells in the Lompoc Plain, San Antonio Valley, and Lompoc Terrace groundwater basins. Metered pumpage during the period 1969-77 from the Lompoc Plain decreased from a high of 3,670 acre-feet in 1969 to a low of 2,441 acre-feet in 1977, while pumpage from the San Antonio Valley increased from a low of 1 ,020 acre-feet in 1969 to a high of 1,829 acre-feet in 1977. Pumpage from the Lompoc Terrace has remained relatively constant and was 187 acre-feet in 1977. In the Barka Slough area of the San Antonio Valley, water levels in four shallow wells declined during 1976 and 1977. Water levels in observation wells in the two aquifers of the Lompoc Terrace ground-water basin fluctuated during the period, but show no long term trends. Chemical analyses or field determinations of temperature and specific conductance were made of 219 water samples collected from 53 wells. In the Lompoc Plain the dissolved-solids concentration in all water samples was more than 625 milligrams per liter, and in most was more than 1,000 milligrams per liter. The manganese concentration in analyzed samples equaled or exceeded the recommended limit of 50 micrograms per liter for public water supplies. Dissolved-solids concentrations increased with time in water samples from two wells east of the Air Force Base in San Antonio Valley. In the base well-field area, concentrations of dissolved solids ranged from 290 to 566 milligrams per liter. Eight analyses show manganese at or above the recommended limit of 50 milligrams per liter. In the Lompoc Terrace area dissolved-solids concentrations ranged from 470 to 824 milligrams per liter. Five new supply wells, nine observation wells, and two exploratory/observation wells were drilled on the base during the period 1972-77. (USGS)

  1. Assessing performance and closure for soil vapor extraction: integrating vapor discharge and impact to groundwater quality.

    PubMed

    Carroll, Kenneth C; Oostrom, Mart; Truex, Michael J; Rohay, Virginia J; Brusseau, Mark L

    2012-02-01

    Soil vapor extraction (SVE) is typically effective for removal of volatile contaminants from higher-permeability portions of the vadose zone. However, contamination in lower-permeability zones can persist due to mass transfer processes that limit the removal effectiveness. After SVE has been operated for a period of time and the remaining contamination is primarily located in lower-permeability zones, the remedy performance needs to be evaluated to determine whether the SVE system should be optimized, terminated, or transitioned to another technology to replace or augment SVE. Numerical modeling of vapor-phase contaminant transport was used to investigate the correlation between measured vapor-phase mass discharge, MF(r), from a persistent, vadose-zone contaminant source and the resulting groundwater contaminant concentrations. This relationship was shown to be linear, and was used to directly assess SVE remediation progress over time and to determine the level of remediation in the vadose zone necessary to protect groundwater. Although site properties and source characteristics must be specified to establish a unique relation between MF(r) and the groundwater contaminant concentration, this correlation provides insight into SVE performance and support for decisions to optimize or terminate the SVE operation or to transition to another type of treatment.

  2. Virus removal by soil passage at field scale and groundwater protection of sandy aquifers.

    PubMed

    Schijven, J F; Hassanizadeh, S M

    2002-01-01

    Virus removal from groundwater by soil passage often appears to be much higher during the first few metres due to the presence of more favorable sites for attachment than thereafter. A model is presented which interprets virus removal as a function of collision efficiencies alpha(beta) and alpha(lambda), inactivation rate coefficient mu(t) and rate parameter gamma. Initial high removal is determined by ab, which decreases exponentially at a rate g to a constant base removal rate that is determined by alpha(lambda) and mu(t). A hypothetical worst case was simulated to calculate the travel distance and time required for 9 log10 protection against virus contamination of groundwater wells in anoxic sandy aquifers. Unfavorable conditions for attachment were assumed. Virus was constantly leaking from a sewage pipe lying at the groundwater table. Mixing reduced virus concentration by 3.1 to 4.0 log10. For an additional 5.0 to 5.9 l log10 protection against virus contamination by attachment and inactivation, residence times of about three to seven times longer than the current guideline of 60 days are needed, depending on abstraction rates, aquifer thickness and grain size of the sand.

  3. Isotopic tracing of landfill leachates and pollutant lead mobility in soil and groundwater.

    PubMed

    Vilomet, J D; Veron, A; Ambrosi, J P; Moustier, S; Bottero, J Y; Chatelet-Snidaro, L

    2003-10-15

    Here we provide evidence of the capability of stable lead isotopes to trace landfill leachate in a shallow groundwater. The municipal landfill we have investigated is located in southeastern France. It has no bottom liner, and wastes are placed directly on the ground. Stable lead isotopes allow the characterization of this landfill leachate signature (206Pb/207Pb = 1.189 +/- 0.004) that is clearly different from that of the local atmosphere (206Pb/207Pb = 1.150 +/- 0.006) and crustal lead (206Pb/207Pb = 1.200 +/- 0.005). Piezometers located in the direct vicinity of the landfill generally display this contaminant imprint. The landfill plume is monitored up to 1000 m downgradient of the landfill, in very good agreement with evaluation from chloride concentration. Meanwhile, 206Pb/207Pb ratios measured at a piezometer located 4600 m downgradient of the landfill suggest a contamination by the landfill plume. This result shows that the complexity of a pollutant plume dispersion in this shallow groundwater system requires several independent tracers to clearly resolve origin and transport pathways for contaminants. Furthermore, seasonal rainfall variation for this Mediterranean mixed Quaternary alluvion reservoir and the use of KCl fertilizers might favor an efficient remobilization of atmospheric lead in plowed soils and its transfer into groundwater as shown by lead isotope systematics.

  4. DEMONSTRATION BULLETIN: IN-SITU STEAM/HOT AIR SOIL STRIPPING TOXIC TREATMENT (USA) INC.

    EPA Science Inventory

    This technology uses steam and hot air to strip volatile organics from contaminated soil. The treatment equipment is mobile and treats the soil in-situ without need for soil excavation or transportation. The organic contaminants volatilized from the soil are condensed and col...

  5. Superfund record of decision (EPA Region 1): New London Submarine Base, Defense Reutilization Marketing Office (contaminated soil and groundwater), Groton, CT, March 31, 1998

    SciTech Connect

    1998-09-01

    The Defense Reutilization and Marketing Office (DRMO) is located on the Naval Submarine Base New London (NSB-NLON), Groton, Connecticut. This Interim Record of Decision (Interim ROD) addresses the contaminated soil and groundwater at this site. This Interim ROD presents the following interim remedy for soil and groundwater at the DRMO: Institutional Controls and Monitoring.

  6. A sitewide approach to the characterization and use of soil and groundwater background at the Hanford Site

    SciTech Connect

    Hoover, J.D.; Ruck, F.A.; LeGore, T.; Thompson, K.M.

    1993-10-01

    A Sitewide approach to the characterization and use of soil and groundwater background has been developed for use in environmental restoration activities on the Hanford Site. Sitewide background more accurately represents the range of background compositions that exist in soil and groundwater at the over 140 Resource Conservation and Recovery Act of 1976 facilities and Comprehensive Environmental Response, Compensation, and Liability Act of 1980 operable units, and provides a more consistent, credible, integrated, and efficient basis for identifying and evaluating contamination in these media than using unit-specific backgrounds.

  7. Acid sulphate soil disturbance and metals in groundwater: implications for human exposure through home grown produce.

    PubMed

    Hinwood, Andrea Lee; Horwitz, Pierre; Appleyard, Steve; Barton, Caroline; Wajrak, Magda

    2006-09-01

    A significant emerging environmental problem is the disturbance and oxidation of soils with high levels of iron sulphide minerals resulting in acidification and causing the mobilization of metals into groundwater. This process is occurring in many parts of the world. In Western Australia, impacted groundwater is extracted by residents for domestic use. We sought to establish domestic use patterns of bore water and the concentration of metals. Sixty-seven domestic bore water samples clearly indicated oxidation of sulphidic materials with heavy metal concentrations ranging for aluminium (soil disturbance in many locations.

  8. Solar Park Impacts on Air and Soil Microclimate

    NASA Astrophysics Data System (ADS)

    Armstrong, A.; Ostle, N. J.; Whitaker, J.

    2015-12-01

    The drive towards low carbon energy sources and increasing energy demand has resulted in a rapid rise in solar photovoltaics across the world. A substantial proportion of photovoltaics are large-scale ground-mounted systems, solar parks, causing a notable land use change. While the impacts of photovoltaic panel production and disposal have been considered, the consequences of the operation of solar parks on the hosting landscape are poorly resolved. Here, we present data which demonstrates that a solar park sited on permanent grassland in the UK significantly impacted the air and soil microclimate. Specifically, we observed (1) cooler soil under the photovoltaic panels during the summer and between the photovoltaic panel rows during the winter; (2) dampening of the diurnal variation in air temperature and absolute humidity from the spring to the autumn; (3) lower photosynthetically active radiation and a lower direct:diffuse under the panels; and (4) reduced wind speed between the panel rows and substantially reduced wind speeds under the panels. Further, there were differences in vegetation type and productivity and greenhouse gas emissions. Given the centrality of climate on ecosystem function, quantifying the microclimatic impacts of this emerging land use change is critical. We anticipate these data will help develop understanding of effects in other climates, under different solar park designs and the implications for the function and service provision of the hosting landscape.

  9. Environmental application of nanotechnology: air, soil, and water.

    PubMed

    Ibrahim, Rusul Khaleel; Hayyan, Maan; AlSaadi, Mohammed Abdulhakim; Hayyan, Adeeb; Ibrahim, Shaliza

    2016-07-01

    Global deterioration of water, soil, and atmosphere by the release of toxic chemicals from the ongoing anthropogenic activities is becoming a serious problem throughout the world. This poses numerous issues relevant to ecosystem and human health that intensify the application challenges of conventional treatment technologies. Therefore, this review sheds the light on the recent progresses in nanotechnology and its vital role to encompass the imperative demand to monitor and treat the emerging hazardous wastes with lower cost, less energy, as well as higher efficiency. Essentially, the key aspects of this account are to briefly outline the advantages of nanotechnology over conventional treatment technologies and to relevantly highlight the treatment applications of some nanomaterials (e.g., carbon-based nanoparticles, antibacterial nanoparticles, and metal oxide nanoparticles) in the following environments: (1) air (treatment of greenhouse gases, volatile organic compounds, and bioaerosols via adsorption, photocatalytic degradation, thermal decomposition, and air filtration processes), (2) soil (application of nanomaterials as amendment agents for phytoremediation processes and utilization of stabilizers to enhance their performance), and (3) water (removal of organic pollutants, heavy metals, pathogens through adsorption, membrane processes, photocatalysis, and disinfection processes).

  10. Arsenic removal from real-life groundwater by adsorption on laterite soil.

    PubMed

    Maji, Sanjoy Kumar; Pal, Anjali; Pal, Tarasankar

    2008-03-01

    The adsorption characteristics of arsenic on laterite soil, a low-cost natural adsorbent, were studied in the laboratory scale using real-life sample. The studies were conducted by both batch and continuous mode. Laterite soil was found to be an efficient adsorbent for arsenic removal from the groundwater collected from arsenic affected area. The initial concentration of arsenic in the sample was 0.33 ppm. Under optimized conditions the laterite soil could remove up to 98% of total arsenic. The optimum adsorbent dose was 20 g/l and the equilibrium time was 30 min. Isotherm studies showed that the process is favorable and spontaneous. The kinetics showed that the removal of arsenic by laterite soil is a pseudo-second-order reaction. In the column study the flow rate was maintained at 1.49 m3/(m2 h). Using 10 cm column depth, the breakthrough and exhaust time found were 6.75 h and 19.0 h, respectively. Height of adsorption zone was 9.85 cm, the rate at which the adsorption zone was moving through the bed was 0.80 cm/h, and the percentage of the total column saturated at breakthrough was 47.12%. The value of adsorption rate coefficient (K) and the adsorption capacity coefficient (N) were 1.21 l/(mgh) and 69.22 mg/l, respectively. Aqueous NaOH (1 M) could regenerate the adsorbent, and the regenerated adsorbent showed higher efficiency. PMID:17658682

  11. Polar metabolites of polycyclic aromatic compounds from fungi are potential soil and groundwater contaminants.

    PubMed

    Boll, Esther S; Johnsen, Anders R; Christensen, Jan H

    2015-01-01

    This study investigated the sorption to soil of water-soluble metabolites from polycyclic aromatic compounds (PACs). The soil fungus Cunninghamella elegans was used to produce PAC metabolites from two un-substituted PACs (phenanthrene, pyrene), three alkyl-substituted PACs (2-methylnaphthalene, 1-methylphenanthrene, 1-methylpyrene), and one sulfur-containing heterocyclic PAC (dibenzothiophene). Fifty-eight metabolites were tentatively identified; metabolites from the un-substituted PACs were hydroxylated and sulfate conjugated, whereas metabolites from alkyl-substituted PACs were sulfate conjugated and either hydroxylated or oxidized to carboxylic acids at the methyl group. The metabolism of the sulfur-containing heterocyclic PAC resulted in sulfate conjugates. The sorption of the PAC metabolites to three soils was determined using a batch equilibrium method, and partition coefficients (Kd's) were calculated for fourteen representative metabolites. Sulfate conjugated metabolites displayed Kd's below 70 whereas the metabolites with both a sulfate and a carboxylic acid group had Kd's below 2.8. The low Kd's of water-soluble PAC metabolites indicate high mobility in soil and a potential for leaching to surface- and groundwaters.

  12. Arsenic removal from real-life groundwater by adsorption on laterite soil.

    PubMed

    Maji, Sanjoy Kumar; Pal, Anjali; Pal, Tarasankar

    2008-03-01

    The adsorption characteristics of arsenic on laterite soil, a low-cost natural adsorbent, were studied in the laboratory scale using real-life sample. The studies were conducted by both batch and continuous mode. Laterite soil was found to be an efficient adsorbent for arsenic removal from the groundwater collected from arsenic affected area. The initial concentration of arsenic in the sample was 0.33 ppm. Under optimized conditions the laterite soil could remove up to 98% of total arsenic. The optimum adsorbent dose was 20 g/l and the equilibrium time was 30 min. Isotherm studies showed that the process is favorable and spontaneous. The kinetics showed that the removal of arsenic by laterite soil is a pseudo-second-order reaction. In the column study the flow rate was maintained at 1.49 m3/(m2 h). Using 10 cm column depth, the breakthrough and exhaust time found were 6.75 h and 19.0 h, respectively. Height of adsorption zone was 9.85 cm, the rate at which the adsorption zone was moving through the bed was 0.80 cm/h, and the percentage of the total column saturated at breakthrough was 47.12%. The value of adsorption rate coefficient (K) and the adsorption capacity coefficient (N) were 1.21 l/(mgh) and 69.22 mg/l, respectively. Aqueous NaOH (1 M) could regenerate the adsorbent, and the regenerated adsorbent showed higher efficiency.

  13. Natural radioactivity content in soil and indoor air of Chellanam.

    PubMed

    Mathew, S; Rajagopalan, M; Abraham, J P; Balakrishnan, D; Umadevi, A G

    2012-11-01

    Contribution of terrestrial radiation due to the presence of naturally occurring radionuclides in soil and air constitutes a significant component of the background radiation exposure to the population. The concentrations of natural radionuclides in the soil and indoor air of Chellanam were investigated with an aim of evaluating the environmental radioactivity level and radiation hazard to the population. Chellanam is in the suburbs of Cochin, with the Arabian Sea in the west and the Cochin backwaters in the east. Chellanam is situated at ∼25 km from the sites of these factories. The data obtained serve as a reference in documenting changes to the environmental radioactivity due to technical activities. Soil samples were collected from 30 locations of the study area. The activity concentrations of (232)Th, (238)U and (40)K in the samples were analysed using gamma spectrometry. The gamma dose rates were calculated using conversion factors recommended by UNSCEAR [United Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation. UNSCEAR (2000)]. The ambient radiation exposure rates measured in the area ranged from 74 to 195 nGy h(-1) with a mean value of 131 nGy h(-1). The significant radionuclides being (232)Th, (238)U and (40)K, their activities were used to arrive at the absorbed gamma dose rate with a mean value of 131 nGy h(-1) and the radium equivalent activity with a mean value of 162 Bq kg(-1). The radon progeny levels varied from 0.21 to 1.4 mWL with a mean value of 0.6 mWL. The thoron progeny varied from 0.34 to 2.9 mWL with a mean value of 0.85 mWL. The ratio between thoron and radon progenies varied from 1.4 to 2.3 with a mean of 1.6. The details of the study, analysis and results are discussed.

  14. Inorganic arsenic speciation in soil and groundwater near in-service chromated copper arsenate-treated wood poles.

    PubMed

    Zagury, Gérald J; Dobran, Simona; Estrela, Sandra; Deschênes, Louise

    2008-04-01

    The environmental impact of chromated copper arsenate (CCA)-treated utility poles is linked to the possible soil and groundwater contamination with arsenic. The objective of the present study was to determine the arsenic speciation in soil and groundwater near in-service CCA-treated poles. Arsenite (As[III]) and arsenate (As[V]) concentrations were determined in 29 surface and subsurface soil samples collected near eight CCA-treated wood poles. Temporal variability of total arsenic concentrations and inorganic arsenic speciation was also assessed in groundwater at two sites through four sampling events over a 19-month period. Arsenic speciation was carried out by a solvent extraction method using ammonium pyrrolidine dithiocarbamate-methyl isobutyl ketone, and total arsenic was quantified by inductively coupled plasma/atomic emission spectrometry/hydride generation. Average arsenic concentrations in surface soils immediately adjacent to utility poles ranged from 153+/-49 to 410+/-150 mg/kg but approached background levels (below 5 mg/kg) within 0.50 m from the poles. A positive correlation was found between surface soil As concentration and total Fe content. In subsurface samples (0.50 m), arsenic levels were generally high in sandy soils (up to 223+/-32 mg/kg), moderate in clayey soils (up to 126+/-26 mg/kg), and relatively lower in organic soils (up to 56+/-24 mg/ kg). Arsenic(V) was the predominant arsenic species in surface (>78%) and subsurface soils (>66%). Total arsenic concentrations in groundwater below the clayey site were high and varied widely over time (79-390 microg/L), with 30 to 68% as As(III). Below the utility pole located on the organic site with a high Fe content, lower total arsenic levels (12-33 microg/L) were found, with As(III) ranging from 0 to 100%.

  15. Estimation of the effect of soil texture on nitrate-nitrogen content in groundwater using optical remote sensing.

    PubMed

    Witheetrirong, Yongyoot; Tripathi, Nitin Kumar; Tipdecho, Taravudh; Parkpian, Preeda

    2011-08-01

    The use of chemical fertilizers in Thailand increased exponentially by more than 100-fold from 1961 to 2004. Intensification of agricultural production causes several potential risks to water supplies, especially nitrate-nitrogen (NO(3) (-)-N) pollution. Nitrate is considered a potential pollutant because its excess application can move into streams by runoff and into groundwater by leaching. The nitrate concentration in groundwater increases more than 3-fold times after fertilization and it contaminates groundwater as a result of the application of excess fertilizers for a long time. Soil texture refers to the relative proportion of particles of various sizes in a given soil and it affects the water permeability or percolation rate of a soil. Coarser soils have less retention than finer soils, which in the case of NO(3) (-)-N allows it to leach into groundwater faster, so there is positive relationship between the percentage of sands and NO(3) (-)-N concentration in groundwater wells. This study aimed to estimate the effect of soil texture on NO(3) (-)-N content in groundwater. Optical reflectance data obtained by remote sensing was used in this study. Our hypothesis was that the quantity of nitrogen leached into groundwater through loam was higher than through clay. Nakhon Pathom province, Thailand, was selected as a study area where the terrain is mostly represented by a flat topography. It was found that classified LANDSAT images delineated paddy fields as covering 29.4% of the study area, while sugarcane covered 10.4%, and 60.2% was represented by "others". The reason for this classified landuse was to determine additional factors, such as vegetation, which might directly affect the quantity of NO(3) (-)-N in soil. Ideally, bare soil would be used as a test site, but in fact, no such places were available in Thailand. This led to an indirect method to estimate NO(3) (-)-N on various soil textures. Through experimentation, it was found that NO(3) (-)-N measured

  16. Estimation of the Effect of Soil Texture on Nitrate-Nitrogen Content in Groundwater Using Optical Remote Sensing

    PubMed Central

    Witheetrirong, Yongyoot; Tripathi, Nitin Kumar; Tipdecho, Taravudh; Parkpian, Preeda

    2011-01-01

    The use of chemical fertilizers in Thailand increased exponentially by more than 100-fold from 1961 to 2004. Intensification of agricultural production causes several potential risks to water supplies, especially nitrate-nitrogen (NO3−-N) pollution. Nitrate is considered a potential pollutant because its excess application can move into streams by runoff and into groundwater by leaching. The nitrate concentration in groundwater increases more than 3-fold times after fertilization and it contaminates groundwater as a result of the application of excess fertilizers for a long time. Soil texture refers to the relative proportion of particles of various sizes in a given soil and it affects the water permeability or percolation rate of a soil. Coarser soils have less retention than finer soils, which in the case of NO3−-N allows it to leach into groundwater faster, so there is positive relationship between the percentage of sands and NO3−-N concentration in groundwater wells. This study aimed to estimate the effect of soil texture on NO3−-N content in groundwater. Optical reflectance data obtained by remote sensing was used in this study. Our hypothesis was that the quantity of nitrogen leached into groundwater through loam was higher than through clay. Nakhon Pathom province, Thailand, was selected as a study area where the terrain is mostly represented by a flat topography. It was found that classified LANDSAT images delineated paddy fields as covering 29.4% of the study area, while sugarcane covered 10.4%, and 60.2% was represented by “others”. The reason for this classified landuse was to determine additional factors, such as vegetation, which might directly affect the quantity of NO3−-N in soil. Ideally, bare soil would be used as a test site, but in fact, no such places were available in Thailand. This led to an indirect method to estimate NO3−-N on various soil textures. Through experimentation, it was found that NO3−-N measured through the loam

  17. Record of Decision for Tank Farm Soil and INTEC Groundwater, Operable Unit 3-14

    SciTech Connect

    L. S. Cahn

    2007-05-16

    This decision document presents the selected remedy for Operable Unit (OU) 3-14 tank farm soil and groundwater at the Idaho Nuclear Technology and Engineering Center (INTEC), which is located on the Idaho National Laboratory (INL) Site. The tank farm was initially evaluated in the OU 3-13 Record of Decision (ROD), and it was determined that additional information was needed to make a final decision. Additional information has been obtained on the nature and extent of contamination in the tank farm and on the impact to groundwater. The selected remedy was chosen in accordance with the Comprehensive Environmental Response, Liability and Compensation Act of 1980 (CERCLA) (42 USC 9601 et seq.), as amended by the Superfund Amendments and Reauthorization Act of 1986 (Public Law 99-499) and the National Oil and Hazardous Substances Pollution Contingency Plan (40 CFR 300). The selected remedy is intended to be the final action for tank farm soil and groundwater at INTEC. The response action selected in this ROD is necessary to protect the public health, welfare, or the environment from actual or threatened releases of hazardous substances into the environment. Such a release or threat of release may present an imminent and substantial endangerment to public health, welfare, or the environment. The remedial actions selected in this ROD are designed to reduce the potential threats to human health and the environment to acceptable levels. In addition, DOE-ID, EPA, and DEQ (the Agencies) have determined that no action is necessary under CERCLA to protect public health, welfare, or the environment at 16 sites located outside the tank farm boundary. The purposes of the selected remedy are to (1) contain contaminated soil as the radionuclides decay in place, (2) isolate current and future workers and biological receptors from contact with contaminated soil, and (3) restore the portion of Snake River Plain Aquifer contaminated by INTEC releases to Idaho Ground Water Quality

  18. Streamflow forecasting and data assimilation: bias in precipitation, soil moisture states, and groundwater fluxes.

    NASA Astrophysics Data System (ADS)

    McCreight, J. L.; Gochis, D. J.; Hoar, T.; Dugger, A. L.; Yu, W.

    2014-12-01

    Uncertainty in precipitation forcing, soil moisture states, and model groundwater fluxes are first-order sources of error in streamflow forecasting. While near-surface estimates of soil moisture are now available from satellite, very few soil moisture observations below 5 cm depth or groundwater discharge estimates are available for operational forecasting. Radar precipitation estimates are subject to large biases, particularly during extreme events (e.g. Steiner et al., 2010) and their correction is not typically available in real-time. Streamflow data, however, are readily available in near-real-time and can be assimilated operationally to help constrain uncertainty in these uncertain states and improve streamflow forecasts. We examine the ability of streamflow observations to diagnose bias in the three most uncertain variables: precipitation forcing, soil moisture states, and groundwater fluxes. We investigate strategies for their subsequent bias correction. These include spinup and calibration strategies with and without the use of data assimilation and the determination of the proper spinup timescales. Global and spatially distributed multipliers on the uncertain states included in the assimilation state vector (e.g. Seo et al., 2003) will also be evaluated. We examine real cases and observing system simulation experiments for both normal and extreme rainfall events. One of our test cases considers the Colorado Front Range flood of September 2013 where the range of disagreement amongst five precipitation estimates spanned a factor of five with only one exhibiting appreciable positive bias (Gochis et al, submitted). Our experiments are conducted using the WRF-Hydro model with the NoahMP land surface component and the data assimilation research testbed (DART). A variety of ensemble data assimilation approaches (filters) are considered. ReferencesGochis, DJ, et al. "The Great Colorado Flood of September 2013" BAMS (Submitted 4-7-14). Seo, DJ, V Koren, and N

  19. Glyphosate and AMPA in U.S. streams, groundwater, precipitation and soils

    USGS Publications Warehouse

    Battaglin, William A.; Meyer, Michael T.; Kuivila, Kathryn M.; Dietze, Julie E.

    2014-01-01

    Herbicides containing glyphosate are used in more than 130 countries on more than 100 crops. In the United States (U.S.), agricultural use of glyphosate [N-(phosphonomethyl)glycine] has increased from less than 10,000 metric tons per year (active ingredient) in 1993 to more than 70,000 metric tons per year in 2006. In 2006, glyphosate accounted for about 20 percent of all herbicide use (by weight of active ingredient). Glyphosate formulations such as Roundup® are used in homes and in agriculture. Part of the reason for the popularity of glyphosate is the perception that it is an “environmentally benign” herbicide that has low toxicity and little mobility or persistence in the environment. The U.S. Geological Survey developed an analytical method using liquid chromatography/tandem mass spectrometry that can detect small amounts of glyphosate and its primary degradation product aminomethylphosphonic acid (AMPA) in water and sediment. Results from more than 2,000 samples collected from locations distributed across the U.S. indicate that glyphosate is more mobile and occurs more widely in the environment than was previously thought. Glyphosate and AMPA were detected (reporting limits between 0.1 and 0.02 micrograms per liter) in samples collected from surface water, groundwater, rainfall, soil water, and soil, at concentrations from less than 0.1 to more than 100 micrograms per liter. Glyphosate was detected more frequently in rain (86%), ditches and drains (71%), and soil (63%); and less frequently in groundwater (3%) and large rivers (18%). AMPA was detected more frequently in rain (86%), soil (82%), and large rivers (78%); and less frequently in groundwater (8%) and wetlands or vernal pools (37%). Most observed concentrations of glyphosate were well below levels of concern for humans or wildlife, and none exceeded the U.S. Environmental Protection Agency’s Maximum Contaminant Level of 700 micrograms per liter. However, the ecosystem effects of chronic low

  20. Delineation of ground-water contamination using soil-gas analyses near Jackson, Tennessee

    USGS Publications Warehouse

    Lee, R.W.

    1991-01-01

    An investigation of the ground-water resources near Jackson, West Tennessee, was conducted during 1988-89. The study included determination of the occurrence of contaminants in the shallow aquifer using soil-gas analyses in the unsaturated zone. Between 1980 and 1988, an underground fuel-storage tank leaked about 3,000 gallons of unleaded fuel to the water table about 4 feet below land surface. A survey of soil gas using a gas chromatograph equipped with a photoionization detector showed concentrations of volatile organic compounds greater than IO, 000 parts per million near the leak These compounds were detected in an area about 240 feet long and 110 feet wide extending west from the point source. The chromatograms provided two distinct 'fingerprints' of volatile organic compounds. The first revealed the presence of benzene, toluene, andxylenes, which are constituents of unleaded fuel, in addition to other volatile compounds, in soil gas in the area near the leak The second did not reveal any detectable benzene, toluene, or xylenes in the soil-gas samples, but showed the presence of other unidentified volatile organic compounds in soil gas north of the storage tank. The distribution of total concentrations of volatile organic compounds in the unsaturated zone indicated that a second plume about 200 feet long and 90 feet wide was present about 100 feet north of the storage tank The second plume could have been the result of previous activities at this site during the 1950's or earlier. Activities at the site are believed to have included storage of solvents used at the nearby railyard and flushing of tanks containing tar onto a gravel-covered parking area. The delineation of these plumes has shown that soil-gas analyses can be a useful technique for identifying areas of contamination with volatile organic compounds in shallow water-table aquifers and may have broad applications in similar situations where the water table is relatively close to the surface.

  1. Mining Environmental Data from a Coupled Modelling System to Examine the Impact of Agricultural Management Practices on Groundwater and Air Quality

    NASA Astrophysics Data System (ADS)

    Garcia, V.; Cooter, E. J.; Hayes, B.; Murphy, M. S.; Bash, J. O.

    2014-12-01

    Excess nitrogen (N) resulting from current agricultural management practices can leach into sources of drinking water as nitrate, increasing human health risks of 'blue baby syndrome', hypertension, and some cancers and birth defects. Nitrogen also enters the atmosphere from land surfaces forming air pollution increasing human health risks of pulmonary and cardio-vascular disease. Characterizing and attributing nitrogen from agricultural management practices is difficult due to the complex and inter-related chemical and biological reactions associated with the nitrogen cascade. Coupled physical process-based models, however, present new opportunities to investigate relationships among environmental variables on new scales; particularly because they link emission sources with meteorology and the pollutant concentration ultimately found in the environment. In this study, we applied a coupled meteorology (NOAA-WRF), agricultural (USDA-EPIC) and air quality modelling system (EPA-CMAQ) to examine the impact of nitrogen inputs from corn production on ecosystem and human health and wellbeing. The coupled system accounts for the nitrogen flux between the land surface and air, and the soil surface and groundwater, providing a unique opportunity to examine the effect of management practices such as type and timing of fertilization, tilling and irrigation on both groundwater and air quality across the conterminous US. In conducting the study, we first determined expected relationships based on literature searches and then identified model variables as direct or surrogate variables. We performed extensive and methodical multi-variate regression modelling and variable selection to examine associations between agricultural management practices and environmental condition. We then applied the regression model to predict and contrast pollution levels between two corn production scenarios (Figure 1). Finally, we applied published health functions (e.g., spina bifida and cardio

  2. Phosphate-Based Mineralization of Arsenic in Contaminated Soil: A Potential Remediation Method for Soil and Groundwater

    NASA Astrophysics Data System (ADS)

    Neupane, G.; Donahoe, R. J.

    2009-12-01

    Soil arsenic contamination resulting from the use of arsenical compounds is a widespread environmental problem. A phosphate-based remediation method which has the potential to immobilize arsenic in both oxidizing and reducing subsurface systems is under laboratory investigation. Although phosphate treatments have been reported to be effective in removal of arsenic from contaminated water, its use in contaminated soils has not been tested. This study aims to (1) determine the competitive adsorption/desorption of arsenate and phosphate at surfaces of ferric hydroxide coated sand in the absence or presence of calcium ions, and (2) develop a method of arsenic fixation which involves phosphoric acid flushing of arsenic from contaminated soil and precipitation of arsenic as apatite-like phases. Ferric hydroxide is a significant arsenic sequestering constituent in soil. Phosphate competes with arsenate for adsorption sites on the ferric hydroxide surface. Batch adsorption experiments conducted using ferric hydroxide coated sand have indicated similar pH-controlled adsorption mechanisms for both arsenate and phosphate. The data obtained from the adsorption experiments is being used to guide the development of a phosphate-based method for soil and groundwater arsenic remediation. Batch experiments were performed using 3g of contaminated soil in contact with 45 ml of treatment fluid (a dilute phosphoric acid and calcium hydroxide solution). Solution samples were collected at 24, 72, 144, 312, and 384 hours, with continuous agitation at 200 rpm. Solution concentrations of phosphorus and calcium generally decreased with time and were primarily controlled by pH. It has been experimentally demonstrated that solution arsenic concentrations can be lowered by maintaining high pH with adequate calcium supply. A batch experiment conducted at pH > 11, using 1 kg of soil in contact with 1 liter of 0.25% H3PO4, precipitated a white material giving an XRD signature indicative of brushite

  3. [Effect of soil texture in unsaturated zone on soil nitrate accumulation and groundwater nitrate contamination in a marginal oasis in the middle of Heihe River basin].

    PubMed

    Su, Yong-Zhong; Yang, Xiao; Yang, Rong

    2014-10-01

    In irrigated agricultural ecosystems, the accumulation, distribution and transfer of nitrate nitrogen (NO(3-)-N) in soil profile and groundwater nitrate pollution were influenced by irrigation and fertilization, and were closely related to soil textural characteristics. In this study, a monitoring section with 10 groundwater observation wells along Heihe River flood land-old oasis croplands-newly cultivated sandy croplands-fixed sandy land outside oasis was established in Pingchuan desert-oasis in Linze county in the middle of Heihe river basin, and groundwater NO(3-)-N concentration was continuously monitored. Soil texture and NO(3-)-N concentration in the unsaturated zone at different landscape locations were determined. The NO(3-)-N transfer change in soil profile, nitrate leaching of soils with different texture and fertility levels in the 0-100 cm layer were analyzed. The results indicated that the vertical distribution of soil texture was sandy loam in the 0-130 cm depth, loam in the 130-190 cm and clay loam in the 190-300 cm for the old oasis croplands. For newly cultivated sandy croplands, sand content was more than 80% in each soil layer of the 0-300 cm profile, although a thin clay layer occurred in the 140-160 cm depth. The clay layer occurred 160 cm below the sand-fixing zone outside oasis. There were significant correlations between soil NO(3-)-N concentration and silt + clay content, and the order of significant degree was the natural soils of sandy lands > the newly cultivated sandy croplands > the old oasis croplands. The loss of N leaching was closely correlated to the silt + caly content in the 0-100 cm soil depth. The groundwater NO(3-)-N concentration varied from 1.01 to 5.17 mg · L(-1), with a mean value of 2.65 mg · L(-1) and from 6.6 to 29.5 mg · L(-1), with an average of 20.8 mg · L(-1) in the area of old oasis croplands and the newly cultivated croplands, respectively. The averaged groundwater NO(3-)-N concentration in the area of newly

  4. [Effect of soil texture in unsaturated zone on soil nitrate accumulation and groundwater nitrate contamination in a marginal oasis in the middle of Heihe River basin].

    PubMed

    Su, Yong-Zhong; Yang, Xiao; Yang, Rong

    2014-10-01

    In irrigated agricultural ecosystems, the accumulation, distribution and transfer of nitrate nitrogen (NO(3-)-N) in soil profile and groundwater nitrate pollution were influenced by irrigation and fertilization, and were closely related to soil textural characteristics. In this study, a monitoring section with 10 groundwater observation wells along Heihe River flood land-old oasis croplands-newly cultivated sandy croplands-fixed sandy land outside oasis was established in Pingchuan desert-oasis in Linze county in the middle of Heihe river basin, and groundwater NO(3-)-N concentration was continuously monitored. Soil texture and NO(3-)-N concentration in the unsaturated zone at different landscape locations were determined. The NO(3-)-N transfer change in soil profile, nitrate leaching of soils with different texture and fertility levels in the 0-100 cm layer were analyzed. The results indicated that the vertical distribution of soil texture was sandy loam in the 0-130 cm depth, loam in the 130-190 cm and clay loam in the 190-300 cm for the old oasis croplands. For newly cultivated sandy croplands, sand content was more than 80% in each soil layer of the 0-300 cm profile, although a thin clay layer occurred in the 140-160 cm depth. The clay layer occurred 160 cm below the sand-fixing zone outside oasis. There were significant correlations between soil NO(3-)-N concentration and silt + clay content, and the order of significant degree was the natural soils of sandy lands > the newly cultivated sandy croplands > the old oasis croplands. The loss of N leaching was closely correlated to the silt + caly content in the 0-100 cm soil depth. The groundwater NO(3-)-N concentration varied from 1.01 to 5.17 mg · L(-1), with a mean value of 2.65 mg · L(-1) and from 6.6 to 29.5 mg · L(-1), with an average of 20.8 mg · L(-1) in the area of old oasis croplands and the newly cultivated croplands, respectively. The averaged groundwater NO(3-)-N concentration in the area of newly

  5. Calculated and Measured Air and Soil Freeze-Thaw Frequencies.

    NASA Astrophysics Data System (ADS)

    Baker, Donald G.; Ruschy, David L.

    1995-10-01

    Freeze-thaw frequencies calculated by eight different counting methods were compared using daily maximum and minimum temperatures from eight north-central United States National Weather Service (NWS) stations. These frequencies were also compared to those obtained using hourly air temperature data from six of the same NWS stations. In addition, the calculated frequencies were compared to measured freeze-thaw frequencies at several depths in a bare soil and a sod-covered soil at the University of Minnesota St. Paul campus climatological observatory.The necessary acceptance of the idealized daily heating cycle when using daily maximum and minimum air temperature data resulted in a higher occurrence of calculated freeze-thaw events than those obtained with hourly data; one method gave 23% more freeze-thaw events with the daily maximum and minimum temperatures.With the freeze-thaw phenomenon centered upon those months in which the mean temperature hovers near O°C, a bimodal frequency occurs at the northern stations (October and April, as at International Falls, Minnesota, and November and March at Fargo, North Dakota), while in warmer climates the bimodal characteristic is replaced by a single-peak frequency in January as at Sedalia and West Plains, Missouri.In the comparison between the calculated freeze-thaw frequencies based on daily maximum and minimum values and the hourly temperature measurements at several heights between the surface and the temperature shelter at the climatological observatory, it was found that the annual total frequencies increased as the height above the surface decreased. For the shallowest height above the surface there was an approximate 13% increase over those measured in the shelter with hourly temperature data.The annual total frequencies of the calculated freeze-thaw events obtained with the daily maximum and minimum temperature measurements in the shelter approximated those actually occurring at the 1-cm depth in a bare soil at the

  6. Geochemical Assessment of Groundwater in the Peri-urban Environment of Buenos Aires, Argentina

    NASA Astrophysics Data System (ADS)

    Gallardo, A.

    2014-12-01

    Groundwater pollution is a major concern in peri-urban environments. Thus, water quality is being investigated at several domestic wells in Brandsen, 70 km south of Buenos Aires, Argentina. To present, about 20 water sources were sampled in orchards and small farms of the area. There is limited data about the wells construction, although collected information suggests that groundwater is derived from the superficial sandy loams of the Pampean Aquifer. Samples were analysed for major inorganic elements using ion chromatography and ICP-MS. Titration was used to estimate alkalinity. Physical characteristics (EC, pH, temperature) were measured on site. Results show that groundwater pH ranges from 6.5 to 7.8, with a specific conductance of 180 to 255 mS/m. A peak of 360 mS/m in one horticultural parcel is associated to local NO3- concentrations up to 140 mg/L. This value exceeds the maximum recommendations set by the WHO (50 mg/L). Considering that fertilizer inputs in that property are negligible, the high levels of NO3- might be attributed to effluents from a neighbour septic tank. An increase in NO3- (>150mg/L) was also detected in two conventional farms. This increase correlates to elevated SO42- concentrations (>300 mg/L) suggesting thus, fertilizers percolation into the saturated zone. The leaching of these fluids might be exacerbated by irrigation during new planting, and accumulations of fertilizer-solids in the root zones from previous seasons. Chloride concentrations average ~90 mg/L and would not pose a threat to health at the moment. Its main origin would be related to connate waters in the loam matrix, although some anthropogenic inputs might occur in the previously described farms. In general, the rest of the analysed elements fall within acceptable levels for drinking purposes as well. Nevertheless, further work is still necessary to better define the fate of the potential harmful elements and assess seasonal variations in water quality.

  7. Assessment of ground-water contamination at Wurtsmith Air Force Base, Michigan, 1982-85

    USGS Publications Warehouse

    Cummings, T.R.; Twenter, F.R.

    1986-01-01

    Study of ground-water contamination at Wurtsmith Air Force Base, Michigan, defined the movement and distribution of volatile organic compounds in the glacial sand and gravel aquifer at known sites of contamination, and has defined new plumes at two other sites. The Arrow Street purge system, installed in 1982 to remove contaminants from the Building 43 plume, has lowered concentrations of trichloroethylene (TCE) in groundwater in the central part of the most contaminated area from a range of 1,000 to 2,000 microg/L to about 200 microg/L. TCE is not escaping off-Base from this area. In the southern part of the Base a plume containing principally TCE and dichloroethylene (DCE) has been delineated along Mission Drive. Maximum concentrations observed were 3,290 microg/L of TCE and 1,480 microg/L of DCE. Hydrologically suitable sites for purge wells were identified in the southern part of the plume using a new ground-water flow model of the Base. A benzene plume near the bulk-fuel storage area has shifted to a more northerly direction under influence of the Arrow Street purge system. Sites initially identified for purging the benzene plume have been repositioned because of the change in contaminant movement. JP-4 fuel was found to be accumulating in wells near the bulk-fuel storage area, largely in response to seasonal fluctuations in the water-table. It is thought to originate from a spill that occurred several years ago. In general, concentrations found in water do not differ greatly from those observed in 1981. Since 1981, concentrations of TCE have decreased significantly in the Alert Apron plume. Near the origin of the plume, the concentration of TCE has decreased from 1,000 microg/L in 1980 to 50 microg/L in 1984. Water from Van Etten Lake near the termination of the plume had only a trace of TCE at one site. Benzene detected in water from well AF2 seems to originate near the former site of buried fuel tanks west of the operational apron. During periods of normal

  8. Estimating the Impact of Vadose Zone Sources on Groundwater to Support Performance Assessment of Soil Vapor Extraction

    SciTech Connect

    Oostrom, Martinus; Truex, Michael J.; Rice, Amy K.; Johnson, Christian D.; Carroll, Kenneth C.; Becker, Dave; Simon, Michelle A.

    2014-03-13

    Soil vapor extraction (SVE) is a prevalent remediation approach for volatile contaminants in the vadose zone. To support selection of an appropriate endpoint for the SVE remedy, an evaluation is needed to determine whether vadose zone contamination has been diminished sufficiently to protect groundwater. When vapor-phase transport is an important component of the overall contaminant fate and transport from a vadose zone source, the contaminant concentration expected in groundwater is controlled by a limited set of parameters, including specific site dimensions, vadose zone properties, and source characteristics. An approach was developed for estimating the contaminant concentration in groundwater resulting from a contaminant source in the vadose zone based on pre-modeling contaminant transport for a matrix of parameter value combinations covering a range of potential site conditions. An interpolation and scaling process are then applied to estimate groundwater impact for site-specific conditions.

  9. Methodology for setting risk-based concentrations of contaminants in soil and groundwater and application to a model contaminated site.

    PubMed

    Fujinaga, Aiichiro; Uchiyama, Iwao; Morisawa, Shinsuke; Yoneda, Minoru; Sasamoto, Yuzuru

    2012-01-01

    In Japan, environmental standards for contaminants in groundwater and in leachate from soil are set with the assumption that they are used for drinking water over a human lifetime. Where there is neither a well nor groundwater used for drinking, the standard is thus too severe. Therefore, remediation based on these standards incurs excessive effort and cost. In contrast, the environmental-assessment procedure used in the United States and the Netherlands considers the site conditions (land use, existing wells, etc.); however, a risk assessment is required for each site. Therefore, this study proposes a new framework for judging contamination in Japan by considering the merits of the environmental standards used and a method for risk assessment. The framework involves setting risk-based concentrations that are attainable remediation goals for contaminants in soil and groundwater. The framework was then applied to a model contaminated site for risk management, and the results are discussed regarding the effectiveness and applicability of the new methodology.

  10. Arsenic behaviour from groundwater and soil to crops: impacts on agriculture and food safety.

    PubMed

    Heikens, Alex; Panaullah, Golam M; Meharg, Andy A

    2007-01-01

    High levels of As in groundwater commonly found in Bangladesh and other parts of Asia not only pose a risk via drinking water consumption but also a risk in agricultural sustainability and food safety. This review attempts to provide an overview of current knowledge and gaps related to the assessment and management of these risks, including the behaviour of As in the soil-plant system, uptake, phytotoxicity, As speciation in foods, dietary habits, and human health risks. Special emphasis has been given to the situation in Bangladesh, where groundwater via shallow tube wells is the most important source of irrigation water in the dry season. Within the soil-plant system, there is a distinct difference in behaviour of As under flooded conditions, where arsenite (AsIII) predominates, and under nonflooded conditions, where arsenate (AsV) predominates. The former is regarded as most toxic to humans and plants. Limited data indicate that As-contaminated irrigation water can result in a slow buildup of As in the topsoil. In some cases the buildup is reflected by the As levels in crops, in others not. It is not yet possible to predict As uptake and toxicity in plants based on soil parameters. It is unknown under what conditions and in what time frame As is building up in the soil. Representative phytotoxicity data necessary to evaluate current and future soil concentrations are not yet available. Although there are no indications that crop production is currently inhibited by As, long-term risks are clearly present. Therefore, with concurrent assessments of the risks, management options to further prevent As accumulation in the topsoil should already have been explored. With regard to human health, data on As speciation in foods in combination with food consumption data are needed to assess dietary exposure, and these data should include spatial and seasonal variability. It is important to control confounding factors in assessing the risks. In a country where malnutrition

  11. In situ denitrification and DNRA rates in soils and underlying groundwater of an integrated constructed wetland

    NASA Astrophysics Data System (ADS)

    Mofizur Rahman Jahangir, Mohammad; Fenton, Owen; McAleer, Eoin; Carroll, Paul; Harrington, Rory; Johnston, Paul; Müller, Christoph; Richards, Karl

    2015-04-01

    Nitrogen (N) removal efficiency in constructed wetlands (CW) is low and again it does not in itself explain whether the removed N species are reactive or benign. Evaluation of environmental benefits of CW necessitates knowing N removal mechanisms and the fate of the removed N in such system. In situ denitrification and DNRA (dissimilatory nitrate reduction to ammonium) rates were measured in an earthen lined 5-cell integrated CW using 15N-enriched nitrate (NO3--N) push-pull method. Measurements were conducted in 2 groundwater depths (shallow- soils in CW bed; and deep- 4 m below CW soils) in 2 contrasting cells (high vs. low nutrient loads) of the CW. Denitrification (N¬2O-N + N2-N) and DNRA were the major NO3--N removal processes accounting together for 54-79% of the total biochemical removal of the applied NO3--N. Of which 14-17 and 40-68% were removed by denitrification and DNRA, respectively. Both the processes significantly differed with CW cells indicating that N transformations depend on the rate of nutrient loads in different cells. They were significantly higher in shallow than deep groundwater. Environmental conditions were favourable for both the processes (i.e. low dissolved oxygen and low redox potential, high dissolved organic carbon, high total carbon and high dissolved organic N) but DNRA rate was favoured over denitrification by high ambient NH4+ concentrations, reduced sulphide and low pH (5.9 - 7.0). Low pH might have limited denitrification to some extent to an incomplete state, being evident by a high N2O-N/(N2O-N+N2-N) ratio (0.35 ± 0.17, SE). Relatively higher N2O-N/(N2O-N+N2-N) ratio and higher DNRA rate over denitrification suggest that the end products of N transformations are reactive. This N2O can be consumed to N2 and/or emit to atmosphere directly and indirectly. The DNRA rate and accumulation of NH4+ indicated that CW is a net source of NH4+ in groundwater. Ammonium produced by DNRA can be fixed in soils and, when exchange sites are

  12. The impact on climate of groundwater induced soil moisture memory : a study with a fully coupled WRF-LEAFHYDRO system

    NASA Astrophysics Data System (ADS)

    Miguez-Macho, Gonzalo; Gómez, Breogán; Martínez-de la Torre, Alberto

    2014-05-01

    Groundwater dynamics and its interactions with the land-atmosphere system are increasingly being taking into consideration in climate and ecosystem modeling studies. A shallow water table slows down drainage and affects soil moisture and potentially evapotranspiration (ET) and climate, particularly in water-limited environments. Our area of interest, the Iberian Peninsula, with a typical Mediterranean climate of dry growing season, is one of such regions where ET is largely constrained by water availability. We investigate how the induced memory on soil moisture by groundwater affects spring precipitation and summer temperatures there using a fully coupled WRF-LEAFHYDRO system. The LEAFHYDRO Land Surface Model includes groundwater dynamics with a realistic water table validated with hundreds of observations over Spain and Portugal. We perform two sets of long-term offline simulations, with and without groundwater forced by ERA-Interim and detailed precipitation analyses for the Iberian Peninsula. The corresponding fully coupled simulations with the Weather Research and Forecasting model (WRF), using exactly the same grid, take initial conditions from the off-line simulations at the end of the winter and are run for spring and summer, when we expect the impact of ET on climate to be largest. After a dry winter, in the run with groundwater soils are considerably wetter in regions with shallow water table and WRF results indicate that during spring the impact on precipitation can be sizeable when synoptic conditions are favorable for convection. Increased ET in the summer due also to more moisture availability in the run with groundwater leads in general to cooler temperatures. These preliminary results highlight the important role of groundwater on climate and the advantages of a fully coupled hydrology-atmospheric modeling system.

  13. Nitrate dynamics in the soil and unconfined aquifer in arid groundwater coupled ecosystems of the Monte desert, Argentina

    NASA Astrophysics Data System (ADS)

    Aranibar, J. N.; Villagra, P. E.; Gomez, M. L.; JobbáGy, E.; Quiroga, M.; Wuilloud, R. G.; Monasterio, R. P.; Guevara, A.

    2011-12-01

    In arid ecosystems, vegetation controls water and nitrate movement in the soil, reducing solute transport to aquifers. Here we analyzed nitrate distribution and transport throughout the soil profile and to the groundwater under different ecologic (vegetation type) and topographic (upland/lowland) situations across sand dune ecosystems with shallow water tables, subject to domestic grazing in the Monte desert. Based on vertical nitrate distributions in deep soil profiles we found that dune uplands (deep groundwater, low productivity) lost relatively more nitrogen than lowlands (shallow groundwater, high productivity), likely reinforcing productivity contrasts along these topographic positions. The traditional practice of nighttime animal concentration in corrals may affect nitrogen transport, with poorly vegetated interdunes at livestock posts showing higher subsoil nitrate concentrations than a well-vegetated nonsettled interdune. Vegetation left its imprint on the vertical distribution of nitrate, as suggested by the presence of a depletion zone that matched the depth of maximum root densities, followed by an underlying zone of accumulation. To explore how nitrogen exports to groundwater could affect water quality and nutrient supply to phreatophyte plants, we characterized groundwater flow patterns based on a potentiometric map and sediment characteristics, and measured groundwater electric conductivity, nitrate and arsenic concentration, and stable isotopes across 29 wells (5.8-12 m deep). Under the present land use and climate conditions, nitrate leaching does not seem to have an important and widespread effect on water quality. Nitrate concentration exceeded established limits for human consumption (45 mg L-1) in only one well, while arsenic concentration exceeded the established limits (10 μg L-1) in all but one well, reaching extreme values of 629 μg L-1. Yet, our analysis suggests that nitrate exports from corrals can reach the aquifer in localized areas

  14. MODELING MICROBIAL TRANSPORT IN SOIL AND GROUNDWATER: MICROBIOLOGISTS CAN ASSIST IN THE DEVELOPMENT OF MODELS OF CONTAMINANT TRANSPORT

    EPA Science Inventory

    A large body of literature describes the processes affecting the fate of microorganisms in the subsurface environment (i.e., soil and groundwater). The fate of microorganisms depends on two main components: survival and transport. other components must be considered when determin...

  15. Semianalytical model predicting transfer of volatile pollutants from groundwater to the soil surface.

    PubMed

    Atteia, Olivier; Höhener, Patrick

    2010-08-15

    Volatilization of toxic organic contaminants from groundwater to the soil surface is often considered an important pathway in risk analysis. Most of the risk models use simplified linear solutions that may overpredict the volatile flux. Although complex numerical models have been developed, their use is restricted to experienced users and for sites where field data are known in great detail. We present here a novel semianalytical model running on a spreadsheet that simulates the volatilization flux and vertical concentration profile in a soil based on the Van Genuchten functions. These widely used functions describe precisely the gas and water saturations and movement in the capillary fringe. The analytical model shows a good accuracy over several orders of magnitude when compared to a numerical model and laboratory data. The effect of barometric pumping is also included in the semianalytical formulation, although the model predicts that barometric pumping is often negligible. A sensitivity study predicts significant fluxes in sandy vadose zones and much smaller fluxes in other soils. Fluxes are linked to the dimensionless Henry's law constant H for H < 0.2 and increase by approximately 20% when temperature increases from 5 to 25 degrees C.

  16. Remediation of groundwater contaminated with MTBE and benzene: the potential of vertical-flow soil filter systems.

    PubMed

    van Afferden, Manfred; Rahman, Khaja Z; Mosig, Peter; De Biase, Cecilia; Thullner, Martin; Oswald, Sascha E; Müller, Roland A

    2011-10-15

    completely diminished (∼100% reduction) after passing through the second filter (PF), with a mean MTBE and benzene concentration of 5±10 and 0.6±0.2 μg L(-1) in the final effluent. The emission rate of volatile organic compounds mass into the air from the systems was less than 1% of the inflow mass loading rate. The results obtained in this study not only demonstrate the feasibility of vertical-flow soil filter systems for treating groundwater contaminated with MTBE and benzene, but can also be considered a major step forward towards their application under full-scale conditions for commercial purposes in the oil and gas industries.

  17. Nitrate Remediation of Soil and Groundwater Using Phytoremediation: Transfer of Nitrogen Containing Compounds from the Subsurface to Surface Vegetation

    NASA Astrophysics Data System (ADS)

    Nelson, Sheldon

    2013-04-01

    Nitrate Remediation of Soil and Groundwater Using Phytoremediation: Transfer of Nitrogen Containing Compounds from the Subsurface to Surface Vegetation Sheldon Nelson Chevron Energy Technology Company 6001 Bollinger Canyon Road San Ramon, California 94583 snne@chevron.com The basic concept of using a plant-based remedial approach (phytoremediation) for nitrogen containing compounds is the incorporation and transformation of the inorganic nitrogen from the soil and/or groundwater (nitrate, ammonium) into plant biomass, thereby removing the constituent from the subsurface. There is a general preference in many plants for the ammonium nitrogen form during the early growth stage, with the uptake and accumulation of nitrate often increasing as the plant matures. The synthesis process refers to the variety of biochemical mechanisms that use ammonium or nitrate compounds to primarily form plant proteins, and to a lesser extent other nitrogen containing organic compounds. The shallow soil at the former warehouse facility test site is impacted primarily by elevated concentrations of nitrate, with a minimal presence of ammonium. Dissolved nitrate (NO3-) is the primary dissolved nitrogen compound in on-site groundwater, historically reaching concentrations of 1000 mg/L. The initial phases of the project consisted of the installation of approximately 1750 trees, planted in 10-foot centers in the areas impacted by nitrate and ammonia in the shallow soil and groundwater. As of the most recent groundwater analytical data, dissolved nitrate reductions of 40% to 96% have been observed in monitor wells located both within, and immediately downgradient of the planted area. In summary, an evaluation of time series groundwater analytical data from the initial planted groves suggests that the trees are an effective means of transfering nitrogen compounds from the subsurface to overlying vegetation. The mechanism of concentration reduction may be the uptake of residual nitrate from the

  18. AIR EMISSIONS FROM THE TREATMENT OF SOILS CONTAMINATED WITH PETROLEUM FUELS AND OTHER SUBSTANCES

    EPA Science Inventory

    The report updates a 1992 report that summarizes available information on air emissions from the treatment of soils contaminated with fuels. Soils contaminated by leaks or spills of fuel products, such as gasoline or jet fuel, are a nationwide concern. Air emissions during remedi...

  19. Analysis of ground-water data for selected wells near Holloman Air Force Base, New Mexico, 1950-95

    USGS Publications Warehouse

    Huff, G.F.

    1996-01-01

    Ground-water-level, ground-water-withdrawal, and ground- water-quality data were evaluated for trends. Holloman Air Force Base is located in the west-central part of Otero County, New Mexico. Ground-water-data analyses include assembly and inspection of U.S. Geological Survey and Holloman Air Force Base data, including ground-water-level data for public-supply and observation wells and withdrawal and water-quality data for public-supply wells in the area. Well Douglas 4 shows a statistically significant decreasing trend in water levels for 1972-86 and a statistically significant increasing trend in water levels for 1986-90. Water levels in wells San Andres 5 and San Andres 6 show statistically significant decreasing trends for 1972-93 and 1981-89, respectively. A mixture of statistically significant increasing trends, statistically significant decreasing trends, and lack of statistically significant trends over periods ranging from the early 1970's to the early 1990's are indicated for the Boles wells and wells near the Boles wells. Well Boles 5 shows a statistically significant increasing trend in water levels for 1981-90. Well Boles 5 and well 17S.09E.25.343 show no statistically significant trends in water levels for 1990-93 and 1988-93, respectively. For 1986-93, well Frenchy 1 shows a statistically significant decreasing trend in water levels. Ground-water withdrawal from the San Andres and Douglas wells regularly exceeded estimated ground-water recharge from San Andres Canyon for 1963-87. For 1951-57 and 1960-86, ground-water withdrawal from the Boles wells regularly exceeded total estimated ground-water recharge from Mule, Arrow, and Lead Canyons. Ground-water withdrawal from the San Andres and Douglas wells and from the Boles wells nearly equaled estimated ground- water recharge for 1989-93 and 1986-93, respectively. For 1987- 93, ground-water withdrawal from the Escondido well regularly exceeded estimated ground-water recharge from Escondido Canyon, and

  20. Hydrogeology and simulation of ground-water flow at Arnold Air Force Base, Coffee and Franklin counties, Tennessee

    USGS Publications Warehouse

    Haugh, C.J.; Mahoney, E.N.

    1994-01-01

    The U.S. Air Force at Arnold Air Force Base (AAFB), in Coffee and Franklin Counties, Tennessee, is investigating ground-water contamination in selected areas of the base. This report documents the results of a comprehensive investigation of the regional hydrogeology of the AAFB area. Three aquifers within the Highland Rim aquifer system, the shallow aquifer, the Manchester aquifer, and the Fort Payne aquifer, have been identified in the study area. Of these, the Manchester aquifer is the primary source of water for domestic use. Drilling and water- quality data indicate that the Chattanooga Shale is an effective confining unit, isolating the Highland Rim aquifer system from the deeper, upper Central Basin aquifer system. A regional ground-water divide, approximately coinciding with the Duck River-Elk River drainage divide, underlies AAFB and runs from southwest to northeast. The general direction of most ground-water flow is to the north- west or to the northwest or to the southeast from the divide towards tributary streams that drain the area. Recharge estimates range from 4 to 11 inches per year. Digital computer modeling was used to simulate and provide a better understanding of the ground-water flow system. The model indicates that most of the ground-water flow occurs in the shallow and Manchester aquifers. The model was most sensitive to increases in hydraulic conductivity and changes in recharge rates. Particle-tracking analysis from selected sites of ground-water contamination indicates a potential for contami- nants to be transported beyond the boundary of AAFB.

  1. Jet grouting for a groundwater cutoff wall in difficult glacial soil deposits

    SciTech Connect

    Flanagan, R.F.; Pepe, F. Jr.

    1997-12-31

    Jet grouting is being used as part of a groundwater cutoff wall system in a major New York City subway construction project to limit drawdowns in an adjacent PCB contamination plume. A circular test shaft of jet grout columns was conducted during the design phase to obtain wall installation parameters. The test program also included shaft wall mapping, and measurements of; inflows, piezometric levels, ground heave and temperature, and jet grout hydraulic conductivity. An axisymmetric finite element method groundwater model was established to back calculate the in-situ hydraulic conductivities of both the surrounding glacial soils and the jet grout walls by matching observed inflows and piezometric levels. The model also verified the use of packer permeability test as a tool in the field to evaluate the hydraulic conductivities of jet grout columns. Both the test program and analytic studies indicated that adjustments to the construction procedures would be required to obtain lower hydraulic conductivities of the jet grout walls for construction. A comparison is made with the conductivities estimated from the test program/analytic studies with those from the present construction.

  2. Soil-Water Balance (SWB) model estimates of soil-moisture variability and groundwater recharge in the South Platte watershed, Colorado

    NASA Astrophysics Data System (ADS)

    Anderson, A. M.; Walker, E. L.; Hogue, T. S.; Ruybal, C. J.

    2015-12-01

    Unconventional energy production in semi-arid regions places additional stress on already over-allocated water systems. Production of shale gas and oil resources in northern Colorado has rapidly increased since 2010, and is expected to continue growing due to advances in horizontal drilling and hydraulic fracturing. This unconventional energy production has implications for the availability of water in the South Platte watershed, where water demand for hydraulic fracturing of unconventional shale resources reached ~16,000 acre-feet in 2014. Groundwater resources are often exploited to meet water demands for unconventional energy production in regions like the South Platte basin, where surface water supply is limited and allocated across multiple uses. Since groundwater is often a supplement to surface water in times of drought and peak demand, variability in modeled recharge estimates can significantly impact projected availability. In the current work we used the Soil-Water Balance Model (SWB) to assess the variability in model estimates of actual evapotranspiration (ET) and soil-moisture conditions utilized to derive estimates of groundwater recharge. Using both point source and spatially distributed data, we compared modeled actual ET and soil-moisture derived from several potential ET methods, such as Thornthwaite-Mather, Jense-Haise, Turc, and Hargreaves-Samani, to historic soil moisture conditions obtained through sources including the Gravity Recovery and Climate Experiment (GRACE). In addition to a basin-scale analysis, we divided the South Platte watershed into sub-basins according to land cover to evaluate model capabilities of estimating soil-moisture parameters with variations in land cover and topography. Results ultimately allow improved prediction of groundwater recharge under future scenarios of climate and land cover change. This work also contributes to complementary subsurface groundwater modeling and decision support modeling in the South Platte.

  3. The Office of Groundwater & Soil Remediation Fiscal Year 2011 Research & Development Program

    SciTech Connect

    Gerdes, Kurt D.; Chamberlain, Skip; Aylward, R. S.; Cercy, Mike; Seitz, Roger; Ramirez, Rosa; Skubal, Karen L.; Marble, Justin; Wellman, Dawn M.; Bunn, Amoret L.; Liang, Liyuan; Pierce, Eric M.

    2011-03-02

    The U.S. Department of Energy's (DOE) Office of Groundwater and Soil Remediation supports technology development and technical assistance for the remediation of environments contaminated by legacy nuclear waste. The core of the program is centered on delivering proactive, responsive expertise and technologies with highly-leveraged, carefully selected investments that maximum impact on life-cycle cleanup costs and risks across the DOE complex. The program currently focuses on four main priorities: improved sampling and characterization strategies, advanced predictive capabilities, enhanced remediation methods, and improved long-term performance evaluation and monitoring. In FY 2010, the program developed a detailed research and development (R and D) plan in support of a larger initiative to integrate R and D efforts across EM. This paper provides an overview of the priority action areas and the program's near-term technical direction.

  4. Design, installation and operational methods of implementing horizontal wells for in situ groundwater and soil remediation

    SciTech Connect

    Larson, R.B.

    1996-12-31

    The design and installation of horizontal wells is the primary factor in the efficiency of the remedial actions. Often, inadequacies in the design and installation of remediation systems are not identified until remedial actions have commenced, at which time, required modifications of operational methods can be costly. The parameters required for designing a horizontal well remediation system include spatial variations in contaminant concentrations and lithology, achievable injection and/or extraction rates, area of influence from injection and/or extraction processes, and limitations of installation methods. As with vertical wells, there are several different methods for the installation of horizontal wells. This paper will summarize four installation methods for horizontal wells, including four sites where horizontal wells have been utilized for in-situ groundwater and soil remediation.

  5. The Office of Groundwater & Soil Remediation Fiscal Year 2011 Research & Development Program

    SciTech Connect

    Pierce, Eric M

    2011-01-01

    The U.S. Department of Energy s (DOE) Office of Groundwater and Soil Remediation supports technology development and technical assistance for the remediation of environments contaminated by legacy nuclear waste. The core of the program is centered on delivering proactive, responsive expertise and technologies with highly-leveraged, carefully selected investments that maximize impact on life-cycle cleanup costs and risks across the DOE complex. The program currently focuses on four main priorities: improved sampling and characterization strategies, advanced predictive capabilities, enhanced remediation methods, and improved long-term performance evaluation and monitoring. In FY 2010, the program developed a detailed research and development (R&D) plan in support of a larger initiative to integrate R&D efforts across EM. This paper provides an overview of the high priority action areas and the program s near-term technical direction.

  6. Development of Enhanced Remedial Techniques for Petroleum Fuel and Related Contaminants in Soil and Groundwater

    SciTech Connect

    Paul Fallgren

    2009-02-10

    Western Research Institute (WRI) in conjunction with Earth Tech and the U.S. Department of Energy (DOE) was to identify proper sites with soils and/or groundwater contaminated by petroleum constituents and MTBE. Biodegradation rates would have been quantitatively assessed in both laboratory and field tests to achieve the optimal destruction of contaminants of concern. WRI and Earth Tech identified a site contaminated with high concentrations of methanol associated with petroleum hydrocarbons. The site was assessed and a remediation project plan was prepared; however, the site was soon acquired by a new company. An agreement between Earth Tech, WRI, and the new site owners could not be reached; therefore, a work was performed to identify a new project site. Task 33 was terminated and the available funding was redeployed to other Tasks after receiving approval from the U.S. DOE task manager.

  7. Groundwater Under Vertisols

    NASA Astrophysics Data System (ADS)

    Kurtzman, D.; Baram, S.; Dahan, O.

    2015-12-01

    Vertisols are cracking clayey soils that: i) usually form in alluvial lowlands where normally, groundwater pools into aquifers; ii) have different types of voids (due to cracking) which make flow and transport of water and gas complex, and iii) are regarded as fertile soils in many areas. The combination of these characteristics results in the unique soil-aquifer phenomena that are highlighted and summarized in this review work. The following four vertisols-aquifer topics will be discussed: 1) Soil cracks as preferential pathways for water and contaminants - Lysimeter to basin-scale observations show the significance of cracks as preferential flow paths in vertisols that bypass matrix blocks in the unsaturated zone. Fresh recharge and groundwater contamination from these fluxes will be reviewed; 2) Soil cracks as deep evaporators and unsaturated-zone salinity - Deep soil samples under uncultivated vertisols in semiarid regions reveal a dry (immobile), saline matrix, partly due to enhanced evaporation through soil cracks. Observations of this phenomenon will be compared and the mechanism of evapoconcentration due to air flow in the cracks is discussed; 3) Impact of cultivation on flushing of the unsaturated zone and aquifer salinization - Land-use change of vertisols from native land to cropland promotes greater fluxes through the saline unsaturated-zone matrix, eventually flushing salts to the aquifer. Different degrees of salt flushing will be presented as well as aquifer salinization on different scales, and a comparison is made with aquifers under other soils; 4) Relatively little nitrate contamination in aquifers under vertisols - A number of observations show that aquifers under cultivated vertisols are somewhat resistant to groundwater contamination by nitrate (the major agriculturally related groundwater problem). Denitrification is probably the main mechanism supporting this resistance, whereas a certain degree of anion-exchange capacity may have a

  8. Survey of hazardous organic compounds in the groundwater, air and wastewater effluents near the Tehran automobile industry.

    PubMed

    Kargar, Mahdi; Nadafi, Kazem; Nabizadeh, Ramin; Nasseri, Simin; Mesdaghinia, Alireza; Mahvi, Amir Hossein; Alimohammadi, Mahmood; Nazmara, Shahrokh; Rastkari, Noushin

    2013-02-01

    Potential of wastewater treatment in car industry and groundwater contamination by volatile organic compounds include perchloroethylene (PCE), trichloroethylene (TCE) and dichloromethane (DCM) near car industry was conducted in this study. Samples were collected in September through December 2011 from automobile industry. Head-space Gas chromatography with FID detector is used for analysis. Mean PCE levels in groundwater ranged from 0 to 63.56 μg L(-1) with maximum level of 89.1 μg L(-1). Mean TCE from 0 to 76.63 μg L(-1) with maximum level of 112 μg L(-1). Due to the data obtained from pre treatment of car staining site and conventional wastewater treatment in car factory, the most of TCE, PCE and DCM removed by pre aeration. Therefor this materials entry from liquid phase to air phase and by precipitation leak out to the groundwater. As a consequence these pollutants have a many negative health effect on the workers by air and groundwater.

  9. Cleaning contaminated soil using electrical heating and air stripping

    SciTech Connect

    Buettner, H.M.; Daily, W.D.

    1995-08-01

    In the summer of 1992, a proof-of-concept demonstration of direct electrical heating and air stripping was conducted for enhancing the removal of a volatile organic contaminant, trichloroethylene (TCSE), from soil. Six electrodes were buried in shallow boreholes so that a target region 6.1 m in diameter and 3.05 m in height was heated by ohmic dissipation of power-line-frequency electrical currents supplied by a diesel generator. Air stripping of TCE contamination from the same region was accomplished from a single well at the center of the heated volume. The electrical energy used during the demonstration was 3.46 {times} 10{sup 10} J (9,600 kW {center_dot} h), and the temperature of the extracted air rose from 16 C to 38 C. An energy balance shows that input energy is consistent with the temperature rise in the target volume and the amount of water vaporized at the electrodes. Prior to heating, the TCE concentration in the vapor decreased from about 80 parts per million by volume (ppm{sub v}) to around 60 ppm{sub v}. As soon as electrical heating started, TCE concentrations began to increase. Some concentration data were lost shortly after electrical heating began. After the system was repaired, the TCE concentration fell rapidly from about 140 ppm{sub v} to 5 ppm{sub v} over a period of about 25 days. A simple two-dimensional model for calculation of heating rates is also presented and verified experimentally. Finally some of the operation and safety issues associated with electrical heating are discussed.

  10. Calcium concentrations in wetland groundwater in relation to water sources and soil conditions in the recharge area

    NASA Astrophysics Data System (ADS)

    Schot, P. P.; Wassen, M. J.

    1993-01-01

    Over the past several decades, vegetation communities in lowland wetlands in Western Europe have changed. Species-rich, low-productivity (i.e. low primary biomass production) communities characteristic of rich fens (fens characterized by microphilous species) have declined and are being replaced by vegetation communities characteristic of high-productivity rich fens, poor fens (fens characterized by ombrophilous species) and bogs. High concentrations of calcium in groundwater are generally believed to be an important controlling factor on the vegetation of rich fens Management for the protection of low-productivity rich fens therefore generally aims at conservation of calcereous groundwater conditions in the root zone of lowland wetlands. This paper relates the occurrence of calcium-rich groundwater in lowland wetlands of the Central Netherlands to water sources and soil conditions in the groundwater recharge area. The chemical composition of the following groundwater types is compared: groundwater recharged at a sandy ridge adjacent to the wetland area (ridge water); groundwater recharged by precipitation within the wetland (peat water); groundwater recharged by surface water in the wetland. Objective hydrological criteria are used to classify groundwater analyses according to recharge area. Oxygen-18 proved an essential criterion for the distinction between genetic groundwater types. It is therefore recommended to make oxygen-18 analysis standard procedure in geohydrological wetland research. Calcium concentrations are generally not suitable as tracers of different types of recharge areas. All groundwater types contain calcium. In contrast to what is generally assumed, lowest concentrations are observed in ridge water. Higher calcium concentrations are found in groundwater recharged in wetlands, especially in infiltrated surface water. Nutrient concentrations in both ridge and peat water are low, while those in infiltrated surface water are significantly higher

  11. Saccharin and other artificial sweeteners in soils: estimated inputs from agriculture and households, degradation, and leaching to groundwater.

    PubMed

    Buerge, Ignaz J; Keller, Martina; Buser, Hans-Rudolf; Müller, Markus D; Poiger, Thomas

    2011-01-15

    Artificial sweeteners are consumed in substantial quantities as sugar substitutes and were previously shown to be ubiquitously present in the aquatic environment. The sweetener saccharin is also registered as additive in piglet feed. Saccharin fed to piglets was largely excreted and, consequently, found in liquid manure at concentrations up to 12 mg/L, where it was stable during 2 months of storage. Saccharin may thus end up in soils in considerable quantities with manure. Furthermore, other studies showed that saccharin is a soil metabolite of certain sulfonylurea herbicides. Sweeteners may also get into soils via irrigation with wastewater-polluted surface water, fertilization with sewage sludge (1-43 μg/L), or through leaky sewers. In soil incubation experiments, cyclamate, saccharin, acesulfame, and sucralose were degraded with half-lives of 0.4-6 d, 3-12 d, 3-49 d, and 8-124 d, respectively. The relative importance of entry pathways to soils was compared and degradation and leaching to groundwater were evaluated with computer simulations. The data suggest that detection of saccharin in groundwater (observed concentrations, up to 0.26 μg/L) is most likely due to application of manure. However, elevated concentrations of acesulfame in groundwater (up to 5 μg/L) may result primarily from infiltration of wastewater-polluted surface water through stream beds.

  12. A THREE-DIMENSIONAL AIR FLOW MODEL FOR SOIL VENTING: SUPERPOSITION OF ANLAYTICAL FUNCTIONS

    EPA Science Inventory

    A three-dimensional computer model was developed for the simulation of the soil-air pressure distribution at steady state and specific discharge vectors during soil venting with multiple wells in unsaturated soil. The Kirchhoff transformation of dependent variables and coordinate...

  13. Phytoremediation: using green plants to clean up contaminate soil, groundwater, and wastewater

    SciTech Connect

    Negri, M.C.; Hinchman, R.R.; Gatliff, E.G.

    1996-07-01

    Phytoremediation, an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost, is defined as the engineered use of green plants (including grasses, forbs, and woody species) to remove, contain, or render harmless such environmental contaminants as heavy metals, trace elements, organic compounds and radioactive compounds in soil or water. Our research includes a successful field demonstration of a plant bioreactor for processing the salty wastewater from petroleum wells; the demonstration is currently under way at a natural gas well site in Oklahoma, in cooperation with Devon Energy Corporation. A greenhouse experiment on zinc uptake in hybrid poplar (Populus sp.) was initiated in 1995. These experiments are being conducted to confirm and extend field data indicating high levels of zinc (4,200 ppm) in leaves of hybrid poplar growing as a cleanup system at a site with zinc contamination in the root zone of some of the trees. Analyses of soil water from experimental pots that had received several doses of zinc indicated that the zinc was totally sequestered by the plants in about 4 hours during a single pass through the root system. The data also showed concentrations of sequestered metal of >38,000 ppm Zn in the dry root tissue. These levels of sequestered zinc exceed the levels found in either roots or tops of many of the known ``hyperaccumulator`` species. Because the roots sequester most of the contaminant taken up in most plants, a major objective of this program is to determine the feasibility of root harvesting as a method to maximize the removal of contaminants from soils. Available techniques and equipment for harvesting plant roots, including young tree roots, are being evaluated and modified as necessary for use with phytoremediation plants.

  14. Removal of volatile organic compounds from groundwater using a rotary air stripper

    SciTech Connect

    Singh, S.P. ); Wilson, J.H.; Counce, R.M.; Villiers-Fisher, J.F.; Jennings, H.L. . Chemical Technology Div.); Lucero, A.J.; Reed, G.D. . Dept. of Chemical Engineering); Ashworth, R.A.; Elliott, M.G. )

    1992-02-01

    In this paper, the performance of a centrifugal vapor-liquid contactor is evaluated for air stripping of jet fuel components from ground water. Hydraulic test data indicated that the Sherwood flooding correlation, which has been proposed for use in designing centrifugal vapor-liquid contactors, overestimates the rotational speeds at which flooding occurs. A concept of the area of a transfer unit (ATU) was introduced in the mass-transfer tests to account for the change in fluid loading with the radius of the packing torus. A new correlation based on the specific surface area of the packing for predicting ATU described the experimental data with a fair degree of accuracy. The power consumed in rotating the packing torus was found to depend mainly on the liquid flow, outer rotor radius, and rotational speed. Previous claims in the literature that the centrifugal vapor-liquid contactor is resistant to fouling because of high shear forces were not found to be valid for groundwater with high iron content.

  15. An Investigation on Soil Chemical Composition and Shallow Groundwater Condition in a Saline Area in Nakhon Panom Province, Thailand

    NASA Astrophysics Data System (ADS)

    Seeboonruang, U.

    2010-12-01

    The Mekong River Basin region is a potential salt-accumulated neighborhood. Several subbasin areas have been reported to have the saline soil problem and these include Lower Songkram River, Nam Oon Brook, Nam Thew Brook, and Namkam Brook. The study area is located on the lower of the Namkam River Basin mainly in 3 districts of the Nakhon Panom Province and these districts are Amphoe That Panom, Amphoe Nakae, and Amphoe Renu Nakhon. Soil salinity is found risen sparsely in some villages of these three districts. Generally, shallow groundwater is known to facilitate the distribution of dissolved salts away from the salinity sources and to pick up the salts to the top soils. Thus, groundwater plays a major role in salinity distribution everywhere. The objective of this research is to investigate the soil chemical composition and shallow groundwater evolution in the study area. Soil samples are analyzed using X-Ray Fluorescence Spectrometer (XRF). The depth to groundwater, groundwater pH, total dissolved solids (TDS), electrical resistivity (EC), and salinity are the parameters and the measurement takes place from October 2007 to present. There are 19 sampling locations distributed in the study area. The depth of the observation wells varies from 4 m to 40 m. Groundwater table is found to be up to 7 m below the groundwater surface and the depth is increasing from December to April. Groundwater pH is constantly less than 7 and greater than 4. Groundwater pH varies significantly between 10 mg/l to 45,000 mg/l and EC also differs between 10 µS/cm to 90,000 µS/cm. Most of groundwater sampled in the study area is slight blackish with salinity measured below 1.00 ppt and these are Ban Don Dang, Ban Wang Yang, Ban Na Khu, Ban Piman Ta, Pan Sala, and Ban Lao Tung. On the other hand, Ban Bo Dong Sorn and Ban Pra Song Noi have very saline shallow groundwater with salinity greater 1ppt. The results from the XRF show that SiO2 and Al2O3 are the main composition and the soil is

  16. Partitioning of arsenic in soil-crop systems irrigated using groundwater: a case study of rice paddy soils in southwestern Taiwan.

    PubMed

    Hsu, Wen-Ming; Hsi, Hsing-Cheng; Huang, You-Tuan; Liao, Chien-Sen; Hseu, Zeng-Yei

    2012-02-01

    The accumulation of As in rice due to groundwater irrigation in paddy fields represents a serious health hazard in South and Southeast Asia. In Taiwan, the fate of As in long-term irrigated paddy fields is poorly understood. Groundwater, surface soil, and rice samples were collected from a paddy field that was irrigated with As-containing groundwater in southwestern Taiwan. The purpose of this study is to elucidate the source and sink of As in the paddy field by comparing the As fractions in the soils that were obtained by a sequential extraction procedure (SEP) with the As uptake of rice. The risks associated with eating rice from the field can thus be better understood. The concentration of As in groundwater varied with time throughout the growing seasons of rice, but always exceeded the permitted maximum (10 μg L(-1)) for drinking water by the WHO. The As concentration increased with the concentration of Fe in the groundwater, supporting the claim that a large amount of As was concentrated in the Fe flocs collected from the internal wall of the groundwater pump. The results of the SEP revealed that As bound with amorphous and crystalline hydrous oxides exhibited high availability in the soils. The root of rice accumulated the largest amount of As, followed by the straw, husk, and grain. Although the As concentration in the rice grain was less than 1.0 mg kg(-1), the estimated intake level was close to the maximum tolerable daily intake of As, as specified by the WHO. PMID:22094052

  17. Processes of bedrock groundwater seepage and their effects on soil water fluxes in a foot slope area

    NASA Astrophysics Data System (ADS)

    Masaoka, Naoya; Kosugi, Ken'ichirou; Yamakawa, Yosuke; Tsutsumi, Daizo

    2016-04-01

    The impact of bedrock groundwater seepage on surface hydrological processes in a foot slope area is an important issue in hillslope hydrology. However, properties of water flux vectors around a seepage area are poorly understood because previous studies have lacked sufficient spatial resolution to capture detailed water movements. Here, we conducted hydrometric observations using unprecedented high-resolution and three-dimensional tensiometer nests in the mountainous foot slope area of the Hirudani experimental basin (Japan). Our findings are summarized as follows: (1) a considerable quantity of groundwater seeped from the bedrock surface in the study site. A groundwater exfiltration flux occurred constantly from a seepage area regardless of rainfall conditions. Saturated lateral flow over the bedrock surface occurred constantly in the region downslope of the seepage area. Groundwater was likely to mixed with soil water infiltration and flowed toward the lower end of the slope. (2) During the wet season, the seepage area expanded ∼3 m in the upslope direction along the bedrock valley in a single season. (3) The pressure head waveform observed in the seepage area showed gradual and significant increases after large rainfall events. However, the seepage pressure propagated within a relatively narrow area: a slope distance of ∼4 m from the seepage point in the downslope direction due to the damping of seepage pressure. (4) Within the whole study area, groundwater seeped from a narrow area located at the bottom of the valley line of the bedrock surface. The shape of the seepage area changed along the valley line in the wet season. Overall, we reveal spatial and temporal variations in bedrock groundwater seepage under the soil mantle and the effects on soil water fluxes. These findings should improve the accuracy of models for predicting surface hydrogeomorphological processes in mountainous hillslopes.

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

    NASA Astrophysics Data System (ADS)

    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.

  19. Investigation of ground-water contamination at a drainage ditch, Installation Restoration Site 4, Naval Air Station Corpus Christi, Corpus Christi, Texas, 2005–06

    USGS Publications Warehouse

    Vroblesky, Don A.; Casey, Clifton C.

    2007-01-01

    The U.S. Geological Survey, in cooperation with the Naval Facilities Engineering Command Southeast, used newly developed sampling methods to investigate ground-water contamination by chlorobenzenes beneath a drainage ditch on the southwestern side of Installation Restoration Site 4, Naval Air Station Corpus Christi, Corpus Christi, Texas, during 2005-06. The drainage ditch, which is a potential receptor for ground-water contaminants from Installation Restoration Site 4, intermittently discharges water to Corpus Christi Bay. This report uses data from a new type of pore-water sampler developed for this investigation and other methods to examine the subsurface contamination beneath the drainage ditch. Analysis of ground water from the samplers indicated that chlorobenzenes (maximum detected concentration of 160 micrograms per liter) are present in the ground water beneath the ditch. The concentrations of dissolved oxygen in the samples (less than 0.05-0.4 milligram per liter) showed that the ground water beneath and near the ditch is anaerobic, indicating that substantial chlorobenzene biodegradation in the aquifer beneath the ditch is unlikely. Probable alternative mechanisms of chlorobenzene removal in the ground water beneath the drainage ditch include sorption onto the organic-rich sediment and contaminant depletion by cattails through uptake, sorption, and localized soil aeration.

  20. When does the fluazifop-P-butyl degradate, TFMP, leach through an agricultural loamy soil to groundwater?

    PubMed

    Vendelboe, Anders L; Norgaard, Trine; Olsen, Preben; de Jonge, Lis W; Rosenbom, Annette E

    2016-08-15

    In intensely cultivated regions, it is crucial to have knowledge of the leaching potential related to pesticides in agricultural production. This is especially true in countries, like Denmark, that base its drinking water supply on untreated groundwater. Since fluazifop-P-butyl (FPB) is applied to control perennial and annual weed grasses in agricultural fields, the objective of this study was to evaluate leaching of its two degradation products - fluazifop-P (FP; free acid; (R)-2-(4-(5-trifluoromethyl-2-pyridyloxy)phenoxy)propionic acid) and TFMP (5-(trifluoromethyl)-2(1H)-pyridinone) - through an agricultural field consisting of loamy soil. Drainage and groundwater samples were collected over a five-year period following four spring/summer applications of FPB, and analysed for both FP and TFMP. FP was only detected once in groundwater, whereas TFMP within the first year after the first and fourth application was detected in concentrations exceeding the value of 0.1μgL(-1) in 100% and 24% of the drainage samples and 9% and 14% of the groundwater samples, respectively. Detections of TFMP up to 18months after application were obtained both in the drainage and groundwater. What differentiated the first and fourth FPB applications from the two others were heavy precipitation events within one week of FPB application, which resulted in rapid transport of TFMP through the discontinuities in the soil and contributed to relatively high TFMP detections in drainage and groundwater. This study indicated that pesticide degradates like TFMP, often being more soluble than the pesticide, have a relatively high leaching potential especially associated with heavy precipitation events shortly after the application. Hence, such pesticide degradates should like in Denmark be considered "relevant" meaning that the EU value for drinking water applies to them, having its leaching potential regulatory assessed based on high quality estimations of their persistence, and be exposed to an

  1. When does the fluazifop-P-butyl degradate, TFMP, leach through an agricultural loamy soil to groundwater?

    PubMed

    Vendelboe, Anders L; Norgaard, Trine; Olsen, Preben; de Jonge, Lis W; Rosenbom, Annette E

    2016-08-15

    In intensely cultivated regions, it is crucial to have knowledge of the leaching potential related to pesticides in agricultural production. This is especially true in countries, like Denmark, that base its drinking water supply on untreated groundwater. Since fluazifop-P-butyl (FPB) is applied to control perennial and annual weed grasses in agricultural fields, the objective of this study was to evaluate leaching of its two degradation products - fluazifop-P (FP; free acid; (R)-2-(4-(5-trifluoromethyl-2-pyridyloxy)phenoxy)propionic acid) and TFMP (5-(trifluoromethyl)-2(1H)-pyridinone) - through an agricultural field consisting of loamy soil. Drainage and groundwater samples were collected over a five-year period following four spring/summer applications of FPB, and analysed for both FP and TFMP. FP was only detected once in groundwater, whereas TFMP within the first year after the first and fourth application was detected in concentrations exceeding the value of 0.1μgL(-1) in 100% and 24% of the drainage samples and 9% and 14% of the groundwater samples, respectively. Detections of TFMP up to 18months after application were obtained both in the drainage and groundwater. What differentiated the first and fourth FPB applications from the two others were heavy precipitation events within one week of FPB application, which resulted in rapid transport of TFMP through the discontinuities in the soil and contributed to relatively high TFMP detections in drainage and groundwater. This study indicated that pesticide degradates like TFMP, often being more soluble than the pesticide, have a relatively high leaching potential especially associated with heavy precipitation events shortly after the application. Hence, such pesticide degradates should like in Denmark be considered "relevant" meaning that the EU value for drinking water applies to them, having its leaching potential regulatory assessed based on high quality estimations of their persistence, and be exposed to an

  2. Estimating the Impact of Vadose Zone Sources on Groundwater to Support Performance Assessment of Soil Vapor Extraction

    SciTech Connect

    Oostrom, Martinus; Truex, Michael J.; Rice, Amy K.; Johnson, Christian D.; Carroll, Kenneth C.; Becker, Dave; Simon, Michelle A.

    2014-03-13

    A generalized conceptual model approach was developed that can be used to estimate the impact of volatile contaminant sources in the vadose zone on groundwater for sites where soil vapor extraction (SVE) operations have diminished source strength. The model has the potential to be broadly applicable for sites where vapor-phase transport dominates. The primary target for this conceptual model and related numerical modeling estimate of groundwater impact is for sites where contaminants have been removed from readily accessible portions of the subsurface, but where contaminants may persist in localized portions of the vadose zone. This paper describes the conceptual model, uses numerical simulations to evaluate the parameters controlling impact to groundwater, and presents estimated results for a range of input conditions. Over the implied ranges, the compliance well concentrations showed (inverse) proportionality with source concentration, Henry’s Law constant, and well screen length. An increase in site recharge caused a linear response in well concentration, with slopes dependent on the groundwater velocity. All other tested parameters resulted in nonlinear responses. The functional relationship between dimensional and transport parameters and resulting groundwater concentrations provide a basis for establishing a structured approach to evaluating the potential risk to groundwater posed by a vadose zone source. This type of evaluation is particularly important to sites where SVE has been applied and reduced contaminant concentrations, but has reached a condition of diminishing returns such that a site must consider whether continuation of SVE, remedy modifications, or closure is warranted.

  3. Assessment of ground-water contamination at Wurtsmith Air Force Base, Michigan, 1982-85

    USGS Publications Warehouse

    Cummings, T.R.; Twenter, F.R.

    1986-01-01

    Continued study of ground-water contamination at Wurtsmith Air Force Base, Michigan, defined the movement and distribution of volatile organic compounds in the glacial sand and gravel aquifer at known sites of contamination, and has defined new plumes at two other sites. The Arrow Street purge system, installed in 1982 to remove contaminants from the Building 43 plume, has lowered concentrations of trichloroethylene in ground water in the central part of the most contaminated area from a range of 1,000 to 2,000 micrograms per liter to about 200 micrograms per liter. Trichloroethylene is not escaping off-Base from this area. In the southern part of the Base a plume containing principally trichloroethylene and dichloroethylene has been delineated along Mission Drive. Maximum concentrations observed were 5,290 micrograms per liter of trichloroethylene and 1,480 micrograms per liter of dichloroethylene. Hydrologically suitable sites for purge wells are identified in the southern part of the plume using a new ground-water flow model of the Base. A benzene plume near the bulk-fuel storage area, delineated in earlier work, lias shifted to a more northerly direction under influence of the Arrow Street purge system. Sites initially identified for purging the benzene plume have been repositioned because of the change in contaminant movement. JP-4 fuel was found to be accumulating in wells near the bulk-fuel storage area, largely in response to seasonal fluctuations in the water table. It is thought to originate from a spill that occurred several years ago. A more thorough definition of contaminants in the northern landfill area has permitted a determination of the most hydrologically suitable sites for purge wells. In general, Concentrations found in water do not differ greatly from those observed in 1981. Since 1981, concentrations of trichloroethylene have decreased significantly in the Alert Apron plume. Near the origin of the plume, the concentration of trichloroethylene

  4. Occurrence and treatment of arsenic in groundwater and soil in northern Mexico and southwestern USA.

    PubMed

    Camacho, Lucy Mar; Gutiérrez, Mélida; Alarcón-Herrera, Maria Teresa; Villalba, Maria de Lourdes; Deng, Shuguang

    2011-04-01

    This review focuses on the occurrence and treatment of arsenic (As) in the arid region of northern Mexico (states of Chihuahua and Coahuila) and bordering states of the southwestern US (New Mexico, Arizona, and Texas), an area known for having high As concentrations. Information assembled and assessed includes the content and probable source of As in water, soil, and sediments and treatment methods that have been applied in the area. High As concentrations were found mainly in groundwater, their source being mostly from natural origin related to volcanic processes with significant anthropogenic contributions near mining and smelting of ores containing arsenic. The affinity of As for solid phases in alkaline conditions common to arid areas precludes it from being present in surface waters, accumulating instead in sediments and shifting its threat to its potential remobilization in reservoir sediments and irrigation waterways. Factors such as oxidation and pH that affect the mobility of As in the subsurface environment are mentioned. Independent of socio-demographic variables, nutritional status, and levels of blood lead, cognitive development in children is being affected when exposed to As. Treatments known to effectively reduce As content to safe drinking water levels as well as those that are capable of reducing As content in soils are discussed. Besides conventional methods, emergent technologies, such as phytoremediation, offer a viable solution to As contamination in drinking water.

  5. Mixed redox catalytic destruction of chlorinated solvents in soils and groundwater.

    PubMed

    Gao, Song; Rupp, Erik; Bell, Suzanne; Willinger, Martin; Foley, Theresa; Barbaris, Brian; Sáez, A Eduardo; Arnold, Robert G; Betterton, Eric

    2008-10-01

    A new thermocatalytic method to destroy chlorinated solvents has been developed in the laboratory and tested in a pilot field study. The method employs a conventional Pt/Rh catalyst on a ceramic honeycomb. Reactions proceed at moderate temperatures in the simultaneous presence of oxygen and a reductant (mixed redox conditions) to minimize catalyst deactivation. In the laboratory, stable operation with high conversions (above 90% at residence times shorter than 1 s) for perchloroethylene (PCE) is achieved using hydrogen as the reductant. A molar ratio of H(2)/O(2)= 2 yields maximum conversions; the temperature required to produce maximum conversions is sensitive to influent PCE concentration. When a homologous series of aliphatic alkanes is used to replace hydrogen as the reductant, the resultant mixed redox conditions also produce high PCE conversions. It appears that the dissociation energy of the C-H bond in the respective alkane molecule is a strong determinant of the activation energy, and therefore the reaction rate, for PCE conversion. This new method was employed in a pilot field study in Tucson, Arizona. The mixed redox system was operated semicontinuously for 240 days with no degradation of catalyst performance and complete destruction of PCE and trichloroethylene in a soil vapor extraction gas stream. Use of propane as the reductant significantly reduced operating costs. Mixed redox destruction of chlorinated solvents provides a potentially viable alternative to current soil and groundwater remediation technologies. PMID:18991945

  6. Mixed redox catalytic destruction of chlorinated solvents in soils and groundwater.

    PubMed

    Gao, Song; Rupp, Erik; Bell, Suzanne; Willinger, Martin; Foley, Theresa; Barbaris, Brian; Sáez, A Eduardo; Arnold, Robert G; Betterton, Eric

    2008-10-01

    A new thermocatalytic method to destroy chlorinated solvents has been developed in the laboratory and tested in a pilot field study. The method employs a conventional Pt/Rh catalyst on a ceramic honeycomb. Reactions proceed at moderate temperatures in the simultaneous presence of oxygen and a reductant (mixed redox conditions) to minimize catalyst deactivation. In the laboratory, stable operation with high conversions (above 90% at residence times shorter than 1 s) for perchloroethylene (PCE) is achieved using hydrogen as the reductant. A molar ratio of H(2)/O(2)= 2 yields maximum conversions; the temperature required to produce maximum conversions is sensitive to influent PCE concentration. When a homologous series of aliphatic alkanes is used to replace hydrogen as the reductant, the resultant mixed redox conditions also produce high PCE conversions. It appears that the dissociation energy of the C-H bond in the respective alkane molecule is a strong determinant of the activation energy, and therefore the reaction rate, for PCE conversion. This new method was employed in a pilot field study in Tucson, Arizona. The mixed redox system was operated semicontinuously for 240 days with no degradation of catalyst performance and complete destruction of PCE and trichloroethylene in a soil vapor extraction gas stream. Use of propane as the reductant significantly reduced operating costs. Mixed redox destruction of chlorinated solvents provides a potentially viable alternative to current soil and groundwater remediation technologies.

  7. Soil treatment with hot air (Cultivit) as alternative to methyl bromide.

    PubMed

    Runia, W T; Molendijk, L P G; Neophytou, G; Greenberger, A

    2006-01-01

    A new development in physical soil treatment is the application of hot air. Hot air treatment is based on blowing extremely hot air into rotavating humid soil. The method has been developed and applied commercially in Israel for the last few years. An increased growth response (IGR) was observed in several crops like potato, cauliflower, kohlrabi and the flower Esclepia, when the soil was treated with hot air prior to planting. Scientific trials were performed in Israel and Cyprus to quantify IGR and to evaluate the efficacy against plant-parasitic nematodes. Squash was grown in tunnels on root-knot nematodes (Meloidogyne javanica and M. incognita) infested fields in sandy (Israel) and clay loam (Cyprus) soils. In Israel hot air treatment was compared with metam sodium and methyl bromide and a cold air treated control. In Cyprus hot air treatment was compared with untreated control. Hot air treatment increased squash yield in Israel with 90 % and in Cyprus with 150%. Root assessments showed that after hot air treatment the root-knot nematodes were still able to infest plants and cause galling damage. Nematode counts were not reduced by hot air treatment. It may be concluded that the general concept of soil disinfestation is not applicable to hot air treatment. Any positive effect in yield could not be explained by reduction in nematode populations in soil. Possible chemical and biological changes in the hot air treated soils need to be identified. Further research will determine the possibilities and limitations of this method in other crops and under various climatic conditions.

  8. Daily and seasonal variations in radon activity concentration in the soil air.

    PubMed

    Műllerová, Monika; Holý, Karol; Bulko, Martin

    2014-07-01

    Radon activity concentration in the soil air in the area of Faculty of Mathematics, Physics and Informatics (FMPI) in Bratislava, Slovak Republic, has been continuously monitored since 1994. Long-term measurements at a depth of 0.8 m and short-term measurements at a depth of 0.4 m show a high variability in radon activity concentrations in the soil. The analysis of the data confirms that regular daily changes in radon activity concentration in the soil air depend on the daily changes in atmospheric pressure. It was also found that the typical annual courses of the radon activity concentration in the soil air (with summer minima and winter maxima) were disturbed by mild winter and heavy summer precipitation. Influence of precipitation on the increase in the radon activity concentration in the soil air was observed at a depth of 0.4 m and subsequently at a depth of 0.8 m.

  9. Column study of Cr(VI) removal by cationic hydrogel for in-situ remediation of contaminated groundwater and soil.

    PubMed

    Tang, Samuel C N; Yin, Ke; Lo, Irene M C

    2011-07-01

    Column experiments were conducted for examining the effectiveness of the cationic hydrogel on Cr(VI) removal from groundwater and soil. For in-situ groundwater remediation, the effects of background anions, humic acid (HA) and pH were studied. Cr(VI) has a higher preference for being adsorbed onto the cationic hydrogel than sulphate, bicarbonate ions and HA. However, the adsorbed HA reduced the Cr(VI) removal capacity of the cationic hydrogel, especially after regeneration of the adsorbents, probably due to the blockage of adsorption sites. The Cr(VI) removal was slightly influenced by the groundwater pH that could be attributed to Cr(VI) speciation. The 6-cycle regeneration and reusability study shows that the effectiveness of the cationic hydrogel remained almost unchanged. On average, 93% of the adsorbed Cr(VI) was recovered in each cycle and concentrated Cr(VI) solution was obtained after regeneration. For in-situ soil remediation, the flushing water pH had an insignificant effect on the release of Cr(VI) from the soils. Multiple-pulse flushing increased the removal of Cr(VI) from the soils. In contrast, more flushing water and longer operation may be required to achieve the same removal level by continuous flushing.

  10. Determination of the origin of groundwater nitrate at an air weapons range using the dual isotope approach.

    PubMed

    Bordeleau, Geneviève; Savard, Martine M; Martel, Richard; Ampleman, Guy; Thiboutot, Sonia

    2008-06-01

    Nitrate is one of the most common contaminants in shallow groundwater, and many sources may contribute to the nitrate load within an aquifer. Groundwater nitrate plumes have been detected at several ammunition production sites. However, the presence of multiple potential sources and the lack of existing isotopic data concerning explosive degradation-induced nitrate constitute a limitation when it comes to linking both types of contaminants. On military training ranges, high nitrate concentrations in groundwater were reported for the first time as part of the hydrogeological characterization of the Cold Lake Air Weapons Range (CLAWR), Alberta, Canada. Explosives degradation is thought to be the main source of nitrate contamination at CLAWR, as no other major source is present. Isotopic analyses of N and O in nitrate were performed on groundwater samples from the unconfined and confined aquifers; the dual isotopic analysis approach was used in order to increase the chances of identifying the source of nitrate. The isotopic ratios for the groundwater samples with low nitrate concentration suggested a natural origin with a strong contribution of anthropogenic atmospheric NOx. For the samples with nitrate concentration above the expected background level the isotopic ratios did not correspond to any source documented in the literature. Dissolved RDX samples were degraded in the laboratory and results showed that all reproduced degradation processes released nitrate with a strong fractionation. Laboratory isotopic values for RDX-derived NO(3)(-) produced a trend of high delta(18)O-low delta(15)N to low delta(18)O-high delta(15)N, and groundwater samples with nitrate concentrations above the expected background level appeared along this trend. Our results thus point toward a characteristic field of isotopic ratios for nitrate being derived from the degradation of RDX.

  11. Seasonal exposure to drought and air warming affects soil Collembola and mites.

    PubMed

    Xu, Guo-Liang; Kuster, Thomas M; Günthardt-Goerg, Madeleine S; Dobbertin, Matthias; Li, Mai-He

    2012-01-01

    Global environmental changes affect not only the aboveground but also the belowground components of ecosystems. The effects of seasonal drought and air warming on the genus level richness of Collembola, and on the abundance and biomass of the community of Collembola and mites were studied in an acidic and a calcareous forest soil in a model oak-ecosystem experiment (the Querco experiment) at the Swiss Federal Research Institute WSL in Birmensdorf. The experiment included four climate treatments: control, drought with a 60% reduction in rainfall, air warming with a seasonal temperature increase of 1.4 °C, and air warming + drought. Soil water content was greatly reduced by drought. Soil surface temperature was slightly increased by both the air warming and the drought treatment. Soil mesofauna samples were taken at the end of the first experimental year. Drought was found to increase the abundance of the microarthropod fauna, but reduce the biomass of the community. The percentage of small mites (body length ≤ 0.20 mm) increased, but the percentage of large mites (body length >0.40 mm) decreased under drought. Air warming had only minor effects on the fauna. All climate treatments significantly reduced the richness of Collembola and the biomass of Collembola and mites in acidic soil, but not in calcareous soil. Drought appeared to have a negative impact on soil microarthropod fauna, but the effects of climate change on soil fauna may vary with the soil type.

  12. INDOOR AIR CONCENTRATION UNIT CONVERSIONS

    EPA Science Inventory

    Migration of volatile chemicals from the subsurface into overlying buildings is called vapor intrusion (VI). Volatile organic chemicals in contaminated soils or groundwater can emit vapors, which can migrate through subsurface soils and may enter the indoor air of overlying buil...

  13. Soil-based filtration technology for air purification: potentials for environmental and space life support application

    NASA Astrophysics Data System (ADS)

    Nelson, Mark; Bohn, Hinrich

    Soil biofiltration, also known as Soil bed reactor (SBR), technology was originally developed in Germany to take advantage of the diversity in microbial mechanisms to control gases producing malodor in industrial processes. The approach has since gained wider international acceptance and seen numerous improvements, for example, by the use of high-organic compost beds to maximize microbial processes. This paper reviews the basic mechanisms which underlay soil processes involved in air purification, advantages and limitations of the technology and the cur-rent research status of the approach. Soil biofiltration has lower capital and operating/energetic costs than conventional technologies and is well adapted to handle contaminants in moderate concentrations. The systems can be engineered to optimize efficiency though manipulation of temperature, pH, moisture content, soil organic matter and airflow rates. SBR technology was modified for application in the Biosphere 2 project, which demonstrated in preparatory research with a number of closed system testbeds that soil could also support crop plants while also serving as soil filters with air pumps to push air through the soil. This Biosphere 2 research demonstrated in several closed system testbeds that a number of important trace gases could be kept under control and led to the engineering of the entire agricultural soil of Biosphere 2 to serve as a soil filtration unit for the facility. Soil biofiltration, coupled with food crop produc-tion, as a component of bioregenerative space life support systems has the advantages of lower energy use and avoidance of the consumables required for other air purification approaches. Expanding use of soil biofiltration can aid a number of environmental applications, from the mitigation of indoor air pollution, improvement of industrial air emissions and prevention of accidental release of toxic gases.

  14. Documentation of input datasets for the soil-water balance groundwater recharge model of the Upper Colorado River Basin

    USGS Publications Warehouse

    Tillman, Fred D

    2015-01-01

    The Colorado River and its tributaries supply water to more than 35 million people in the United States and 3 million people in Mexico, irrigating more than 4.5 million acres of farmland, and generating about 12 billion kilowatt hours of hydroelectric power annually. The Upper Colorado River Basin, encompassing more than 110,000 square miles (mi2), contains the headwaters of the Colorado River (also known as the River) and is an important source of snowmelt runoff to the River. Groundwater discharge also is an important source of water in the River and its tributaries, with estimates ranging from 21 to 58 percent of streamflow in the upper basin. Planning for the sustainable management of the Colorado River in future climates requires an understanding of the Upper Colorado River Basin groundwater system. This report documents input datasets for a Soil-Water Balance groundwater recharge model that was developed for the Upper Colorado River Basin.

  15. New species of ice nucleating fungi in soil and air

    NASA Astrophysics Data System (ADS)

    Fröhlich-Nowoisky, Janine; Hill, Thomas C. J.; Pummer, Bernhard G.; Franc, Gray D.; Pöschl, Ulrich

    2014-05-01

    -8°C. The IN seem not be bound to cells because they can be easily washed off the mycelium. They pass through a 0.1 µm filter and can be inactivated by 60°C treatment. Ongoing investigations of various soil and air samples indicate that diverse ice nucleation active fungi from more than one phylum are not only present in air and soil but can also be abundant components of the cultivable community. A recently discovered group of IN fungi in soil was also found to possess easily suspendable IN smaller than 300 kDa. Ice nucleating fungal mycelium may ramify topsoils and release cell-free IN into it. If some of these IN survive decomposition or are adsorbed onto mineral surfaces this contribution will accumulate over time, perhaps to be transported with soil dust and influencing its ice nucleating properties. Thanks for collaboration and support to M.O. Andreae, B. Baumgartner, I. Germann-Müller, T. Godwill, L.E. Hanson, A.T. Kunert, J. Meeks, T. Pooya, S. Lelieveld, J. Odhiambo Obuya, C. Ruzene-Nespoli, and D. Sebazungu. The Max Planck Society (MPG), Ice Nuclei research UnIT (INUIT), the German Research Foundation (PO1013/5-1), and the National Science Foundation (NSF, grant 0841542) are acknowledged for financial support. 1. Fröhlich-Nowoisky, J., et al. (2009) Proc. Natl Acad. Sci., 106, 12814-12819 2. Després, V. R., et al. (2012) Tellus B, 64, 15598 3. Georgakopoulos, D.G., et al. (2009) Biogeosciences, 6, 721-737 4. Pouleur, S., et al. (1992) Appl. Environ. Microbiol. 58, 2960-2964 5. Burrows, S.M., et al. (2009a) Atmos. Chem. Phys., 9, (23), 9281-9297 6. Burrows, S.M., et al. (2009b) Atmos. Chem. Phys., 9, (23), 9263-9280 7. Fröhlich-Nowoisky, J., et al. (2012) Biogeosciences, 9, 1125-1136 8. Huffman A. J. et al. (2013) Atmos. Chem. Phys., 13, 6151-6164

  16. Environmental monitoring of chromium in air, soil, and water.

    PubMed

    Vitale, R J; Mussoline, G R; Rinehimer, K A

    1997-08-01

    Historical uses of chromium have resulted in its widespread release into the environment. In recent years, a significant amount of research has evaluated the impact of chromium on human health and the environment. Additionally, numerous analytical methods have been developed to identify and quantitate chromium in environmental media in response to various state and federal mandates such as CERCLA, RCRA, CWA, CAA, and SWDA. Due to the significant toxicity differences between trivalent [Cr(III)] and hexavalent [Cr(VI)] chromium, it is essential that chromium be quantified in these two distinct valence states to assess the potential risks to exposure to each in environmental media. Speciation is equally important because of their marked differences in environmental behavior. As the knowledge of risks associated with each valence state has grown and regulatory requirements have evolved, methods to accurately quantitate these species at ever-decreasing concentrations within environmental media have also evolved. This paper addresses the challenges of chromium species quantitation and some of the most relevant current methods used for environmental monitoring, including ASTM Method D5281 for air, SW-846 Methods 3060A, 7196A and 7199 for soils, sediments, and waste, and U.S. EPA Method 218.6 for water.

  17. Environmental monitoring of chromium in air, soil, and water.

    PubMed

    Vitale, R J; Mussoline, G R; Rinehimer, K A

    1997-08-01

    Historical uses of chromium have resulted in its widespread release into the environment. In recent years, a significant amount of research has evaluated the impact of chromium on human health and the environment. Additionally, numerous analytical methods have been developed to identify and quantitate chromium in environmental media in response to various state and federal mandates such as CERCLA, RCRA, CWA, CAA, and SWDA. Due to the significant toxicity differences between trivalent [Cr(III)] and hexavalent [Cr(VI)] chromium, it is essential that chromium be quantified in these two distinct valence states to assess the potential risks to exposure to each in environmental media. Speciation is equally important because of their marked differences in environmental behavior. As the knowledge of risks associated with each valence state has grown and regulatory requirements have evolved, methods to accurately quantitate these species at ever-decreasing concentrations within environmental media have also evolved. This paper addresses the challenges of chromium species quantitation and some of the most relevant current methods used for environmental monitoring, including ASTM Method D5281 for air, SW-846 Methods 3060A, 7196A and 7199 for soils, sediments, and waste, and U.S. EPA Method 218.6 for water. PMID:9380841

  18. N leaching to groundwater from dairy production involving grazing over the winter on a clay-loam soil.

    PubMed

    Necpalova, M; Fenton, O; Casey, I; Humphreys, J

    2012-08-15

    This study investigated concentrations of various N species in shallow groundwater (<2.2m below ground level) and N losses from dairy production involving grazing over the winter period on a clay loam soil with a high natural attenuation capacity in southern Ireland (52°51'N, 08°21'W) over a 2-year period. A dense network of shallow groundwater piezometers was installed to determine groundwater flow direction and N spatial and temporal variation. Estimated vertical travel times through the unsaturated zone (<0.5 yr, time lag) allowed the correlation of management with groundwater N within a short space of time. There was a two way interaction of the system and sampling date (P<0.05) on concentrations of DON, oxidised N and NO(3)(-)-N. In contrast, concentrations of NH(4)(+)-N and NO(2)(-)-N were unaffected by the dairy system. Grazing over the winter had no effect on N losses to groundwater. Mean concentrations of DON, NH(4)(+)-N, NO(2)(-)-N and NO(3)(-)-N were 2.16, 0.35, 0.01 and 0.37 mg L(-1) respectively. Soil attenuation processes such as denitrification and DNRA resulted in increased NH(4)(+)-N levels. For this reason, DON and NH(4)(+)-N represented the highest proportion of N losses from the site. Some of the spatial and temporal variation of N concentrations was explained by correlations with selected chemical and hydro-topographical parameters (NO(3)(-)-N/Cl(-) ratio, distance of the sampling point from the closest receptor, watertable depth, depth of sampling piezometer, DOC concentration). A high explanatory power of NO(3)(-)-N/Cl(-) ratio and the distance of the sampling point from the closest receptor indicated the influence of point sources and groundwater-surface water interactions.

  19. Air stripping. (Latest citations from the NTIS database). Published Search

    SciTech Connect

    Not Available

    1993-04-01

    The bibliography contains citations concerning the application of air stripping techniques to water treatment, including groundwater decontamination and wastewater purification. The advantages and disadvantages of air stripping over other water treatment processes are discussed. Cleanup of the organic emissions generated by air stripping is also considered. The primary applications of air stripping are in groundwater and soil cleanup. (Contains a minimum of 71 citations and includes a subject term index and title list.)

  20. Monitoring of soil and groundwater contamination following a pipeline explosion and petroleum product spillage in Ijegun, Lagos Nigeria.

    PubMed

    Doherty, Victoria Funmilayo; Otitoloju, Adebayo Akeem

    2013-05-01

    In May 2008, an accidental damage of a Nigerian National Petroleum Corporation (NNPC) pipeline occurred in Ijegun area of Lagos, Nigeria, resulting in oil spillage and consequent contamination of the environment. The residual concentration of the total hydrocarbon (THC) and benzene, toluene, ethylbenzene, and xylene (BTEX) in the groundwater and soil was therefore investigated between March 2009 and July 2010. Results showed elevated THC mean levels in groundwater which were above the World Health Organization maximum admissible value of 0.1 mg/l. THC values as high as 757.97 mg/l in groundwater and 402.52 mg/l in soil were observed in March 2009. Pronounced seasonal variation in the concentration of THC in groundwater and soil samples show that there was significant (P < 0.05) difference in the measured concentration of THC between each season (dry and wet), with the highest being in the dry season and between the years 2009 and 2010. Significant hydrocarbon contamination, 500 m beyond the explosion site and 25 months after the incident, was observed revealing the extent of the spillage of petroleum products. The highest concentrations of 16.65 μg/l (benzene), 2.08 μg/l (toluene), and 4864.79 μg/l (xylene) were found in stations within the 100 m buffer zone. Most of the samples of groundwater taken were above the target value of 0.2 μg/l set for BTEX compounds by the Environmental Guidelines and Standards for Petroleum Industry in Nigeria. The level of hydrocarbon in the impacted area calls for concern and remediation of the area is urgently needed to reduce further negative impact on the ecosystem.

  1. Seasonal changes in ground-water quality and ground-water levels and directions of ground-water movement in southern Elmore County, southwestern Idaho, including Mountain Home Air Force Base, 1990-1991

    USGS Publications Warehouse

    Young, H.W.; Parliman, D.J.; Jones, Michael L.

    1992-01-01

    The study area is located in southern Elmore County, southwestern Idaho, and includes the Mountain Home Air Force Base located approximately 10 mi southwest of the city of Mountain Home. Chemical analyzes have been made periodically since the late 1940's on water samples from supply wells on the Air Force Base. These analyses indicate increases in specific conductance and in concentrations of nitrogen compounds, chloride, and sulfate. The purposes of this report, which was prepared in cooperation with the Department of the Air Force, are to describe the seasonal changes in water quality and water levels and to depict the directions of ground-water movement in the regional aquifer system and perched-water zones. Although data presented in this report are from both the regional ground-water system and perched-water zones, the focus is on the regional system. A previous study by the U.S. Geological Survey (Parliman and Young, 1990) describes the areal changes in water quality and water levels during the fall of 1989. During March, July, and October 1990, 141 wells were inventoried and depth to water was measured. Continuous water-level recorders were installed on 5 of the wells and monthly measurements of depth to water were made in 17 of the wells during March 1990 through February 1991. Water samples from 33 wells and 1 spring were collected during the spring and fall of 1990 for chemical analyses. Samples also were collected monthly from 11 of those wells during April to September 1990 (table 1). Selected well-construction and water-use data and measurements of depth to water for 141 wells are given in table 2 (separated sheets in envelope). Directions of ground-water movement and selected hydrographs showing seasonal fluctuations of water levels in the regional ground-water system and perched-water zones are shown on sheet 2. Changes in water levels in the regional ground-water system during March to October 1990 are shown on sheet 2.

  2. Feasibility analysis of using inverse modeling for estimating natural groundwater recharge from a large-scale soil moisture monitoring network

    NASA Astrophysics Data System (ADS)

    Wang, Tiejun; Franz, Trenton E.; Yue, Weifeng; Szilagyi, Jozsef; Zlotnik, Vitaly A.; You, Jinsheng; Chen, Xunhong; Shulski, Martha D.; Young, Aaron

    2016-02-01

    Despite the importance of groundwater recharge (GR), its accurate estimation still remains one of the most challenging tasks in the field of hydrology. In this study, with the help of inverse modeling, long-term (6 years) soil moisture data at 34 sites from the Automated Weather Data Network (AWDN) were used to estimate the spatial distribution of GR across Nebraska, USA, where significant spatial variability exists in soil properties and precipitation (P). To ensure the generality of this study and its potential broad applications, data from public domains and literature were used to parameterize the standard Hydrus-1D model. Although observed soil moisture differed significantly across the AWDN sites mainly due to the variations in P and soil properties, the simulations were able to capture the dynamics of observed soil moisture under different climatic and soil conditions. The inferred mean annual GR from the calibrated models varied over three orders of magnitude across the study area. To assess the uncertainties of the approach, estimates of GR and actual evapotranspiration (ETa) from the calibrated models were compared to the GR and ETa obtained from other techniques in the study area (e.g., remote sensing, tracers, and regional water balance). Comparison clearly demonstrated the feasibility of inverse modeling and large-scale (>104 km2) soil moisture monitoring networks for estimating GR. In addition, the model results were used to further examine the impacts of climate and soil on GR. The data showed that both P and soil properties had significant impacts on GR in the study area with coarser soils generating higher GR; however, different relationships between GR and P emerged at the AWDN sites, defined by local climatic and soil conditions. In general, positive correlations existed between annual GR and P for the sites with coarser-textured soils or under wetter climatic conditions. With the rapidly expanding soil moisture monitoring networks around the

  3. U-ages in soils and groundwater evidencing wet periods 400-600kyr ago in southeast Brazil.

    PubMed

    Bonotto, D M; Jiménez-Rueda, J R

    2007-07-01

    (238)U and its radiogenic daughter (234)U have been utilized for dating soil formation and groundwater residence time during the last 1.5 million years, in this case based on the U-dissolution/precipitation occurring during modifications of the oxidation-reduction conditions. In this paper, we report a 400-600kyr proxy of wet periods from sediments occurring in a soil profile developed over rocks outcropping at the Paraná sedimentary basin in Brazil, and from groundwater exploited of Guarani aquifer at the same basin. The approaches indicated successful use of the U-modeled ages for suggesting wet periods exceeding the past 116-210kyr from previous studies.

  4. Operable Unit 3-14, Tank Farm Soil and INTEC Groundwater Remedial Design/Remedial Action Scope of Work

    SciTech Connect

    D. E. Shanklin

    2007-07-25

    This Remedial Design/Remedial Action (RD/RA) Scope of Work pertains to OU 3-14 Idaho Nuclear Technology and Engineering Center and the Idaho National Laboratory and identifies the remediation strategy, project scope, schedule, and budget that implement the tank farm soil and groundwater remediation, in accordance with the May 2007 Record of Decision. Specifically, this RD/RA Scope of Work identifies and defines the remedial action approach and the plan for preparing the remedial design documents.

  5. Coupling a spatio-temporally distributed soil water budget with stream-depletion functions and a groundwater numerical model to constrain stakeholder-driven management of groundwater-dependent ecosystems

    NASA Astrophysics Data System (ADS)

    Foglia, Laura; McNally, Alison; Harter, Thomas

    2013-04-01

    Excessive groundwater use may significantly impact groundwater dependent ecosystems through increased streamflow depletion, particularly in semi-arid and arid regions. The effects may be seasonal or long-term trends. They may be further exacerbated by climate change. Here, we develop a spatio-temporally distributed soil water budget model and that is coupled with an analytical model for stream depletion from groundwater pumping to assess seasonal impacts of groundwater pumping on streamflow during critical low flow periods. We demonstrate the applicability of the tool for the Scott Valley in Northern California, where protected salmon depend on sufficient summer streamflow, which is impacted by seasonal pumping. In this example, results suggest that increased recharge of snowmelt-driven runoff in the period immediately preceding the critical low streamflow season, and transfer of groundwater pumping during the critical period away from the stream are promising tools to address ecosystem concerns. Comparison to numerical model results suggests that the water mass balance model coupled to an analytical streamflow model provides a potentially powerful tool to build intuitive system knowledge among stakeholders enabling them to creative scenario development. Detailed impacts of management practices are evaluated with fully-three-dimensional groundwater-surface water flow model linked to the soil water budget model. Sensitivity analysis and calibration are performed on the coupled soil water budget - groundwater - surface water model. The results drive data collection efforts and are applied to develop uncertainty analyses for future scenarios.

  6. Removing a small quantity of THT from gas storage groundwater through air stripping and gas-phase carbon adsorption

    SciTech Connect

    Girod, J.F.; Leclerc, J.P.; Muhr, H.

    1996-12-31

    This paper deals with the response to a case of contaminated groundwater located in France. The natural gas is stored during summer in porous underground rocks. When energy requirements increase (particularly in winter), gas is drawn off, but water is also pumped during this operation. The water has a strong characteristic odour of the TetraHydroThiophene (THT), which has been used by Gaz de France as an additive in order to detect gas leakages because of its strong odour. Unfortunately, the presence of THT in medium other than natural gas can be responsible for safety problems. Gas stripping combined with adsorption on granular activated carbon was chosen to obtain removal of THT from the groundwater. The gas to water ratio for stripping column is higher than usual and the gas used for stripping was recycled in order to prevent air pollution. Carbon consumption is approximately 3 tons a year. 8 refs., 5 figs., 2 tabs.

  7. Simulation of picloram, atrazine, and simazine leaching through two New Zealand soils and into groundwater using HYDRUS-2D

    NASA Astrophysics Data System (ADS)

    Pang, Liping; Close, Murray E.; Watt, James P. C.; Vincent, Keith W.

    2000-06-01

    Two 15 m×15 m field plots, a Te Awa silt loam and a Twyford fine sandy loam, located in Hawkes Bay, New Zealand, were applied with bromide, picloram, atrazine, and simazine. The Te Awa subsoil was a heterogeneous coarse sand and sandy gravel, and the Twyford subsoil was a more homogenous fine sandy loam. The underlying aquifers were composed of alluvial gravels at both sites with the water tables generally between 4-5 m below ground level. The sites were monitored for 2.2-3.5 years at approximately monthly intervals using suction cups in the unsaturated zone and monitoring wells in groundwater. HYDRUS-2D was used to simulate water movement and solute transport in soil and groundwater in a domain with a depth of 10 m and length of 68 m, including a 4.5-m unsaturated zone. The model simulated well the general trend of field observations for soil water content ( θ) and potential ( ψs), and the values matched better for the soils with less heterogeneity. For the soils with significant surface cracks, the simulated θ values were overestimated. On the other hand, for the soil layer perching on top of a less permeable layer, the simulated θ values were underestimated. Simulated pesticide concentrations using the "best available literature values" (BALVs) of organic carbon distribution coefficient ( Koc) and half-life ( T1/2) were generally lower than those observed. At early times in the trails, most simulations using BALVs were still within the same order of magnitude as observed concentrations for the shallow depths. However, at greater depths and later times, there were major differences between observed and simulated concentrations. The model was then calibrated for Koc and T1/2 values using observed data with an aid of the PEST optimisation package. Despite higher organic contents found in the topsoil, optimised Koc values for pesticides were consistently lower for the topsoil than for the subsoil, and were also lower than the BALVs except for picloram, possibly

  8. Soil organic matter-hydrogen peroxide dynamics in the treatment of contaminated soils and groundwater using catalyzed H2O2 propagations (modified Fenton's reagent).

    PubMed

    Bissey, Lauren L; Smith, Jeffrey L; Watts, Richard J

    2006-07-01

    The interactions between catalyzed H(2)O(2) propagations (CHP-i.e. modified Fenton's reagent) and soil organic matter (SOM) during the treatment of contaminated soils and groundwater was studied in a well-characterized surface soil. The fate of two fractions of SOM, particulate organic matter (POM) and nonparticulate organic matter (NPOM), during CHP reactions was evaluated using concentrations of hydrogen peroxide from 0.5 to 3M catalyzed by soluble iron (III), an iron (III)-ethylenediamine tetraacetic acid (EDTA) chelate, or naturally-occurring soil minerals. The destruction of total SOM in CHP systems was directly proportional to the hydrogen peroxide dosage, and was significantly greater at pH 3 than at neutral pH; furthermore, SOM destruction occurred predominantly in the NPOM fraction. At pH 3, SOM did not affect hydrogen peroxide decomposition rates or hydroxyl radical activity in CHP reactions. However, at neutral pH, increasing the mass of SOM decreased the hydrogen peroxide decomposition rate and increased the rate of hydroxyl radical generation in CHP systems. These results show that, while CHP reactions destroy some of the organic carbon pools, SOM does not have a significant effect on the CHP treatment of soils and groundwater. PMID:16815526

  9. Organizing groundwater regimes and response thresholds by soils: A framework for understanding runoff generation in a headwater catchment

    NASA Astrophysics Data System (ADS)

    Gannon, John P.; Bailey, Scott W.; McGuire, Kevin J.

    2014-11-01

    A network of shallow groundwater wells in a headwater catchment at the Hubbard Brook Experimental Forest in New Hampshire, U.S. was used to investigate the hydrologic behavior of five distinct soil morphological units. The soil morphological units were hypothesized to be indicative of distinct water table regimes. Water table fluctuations in the wells were characterized by their median and interquartile range of depth, proportion of time water table was present in the solum, and storage-discharge behavior of subsurface flow. Statistically significant differences in median, interquartile range, and presence of water table were detected among soil units. Threshold responses were identified in storage-discharge relationships of subsurface flow, with thresholds varying among soil units. These results suggest that soil horizonation is indicative of distinct groundwater flow regimes. The spatial distribution of water table across the catchment showed variably connected/disconnected active areas of runoff generation in the solum. The spatial distribution of water table and therefore areas contributing to stormflow is complex and changes depending on catchment storage.

  10. New species of ice nucleating fungi in soil and air

    NASA Astrophysics Data System (ADS)

    Froehlich, Janine; Hill, Tom; Franc, Gary; Poeschl, Ulrich

    2013-04-01

    Primary biological aerosol particles (PBAP) are ubiquitous in the atmosphere (1). Several types of PBAP have been identified as ice nuclei (IN) that can initiate the formation of ice at relatively high temperatures (2, 3). The best-known biological IN are common plant-associated bacteria. The IN activity of these bacteria is due to a surface protein on the outer cell membrane that catalyses ice formation, for which the corresponding gene has been identified and detected by DNA analysis (2). Fungal spores or hyphae can also act as IN, but the biological structures responsible for their IN activity have not yet been elucidated. Furthermore, the abundance, diversity, sources, seasonality, properties, and effects of fungal IN in the atmosphere have neither been characterized nor quantified. Recent studies have shown that airborne fungi are highly diverse (1), and that atmospheric transport leads to efficient exchange of species among different ecosystems (4, 5). The results presented in Fröhlich-Nowoisky et al. 2012 (6) clearly demonstrate the presence of geographic boundaries in the global distribution of microbial taxa in air, and indicate that regional differences may be important for the effects of microorganisms on climate and public health. Thus, the objective of this study is the identification and quantification of ice nuclei-active fungi in and above ecosystems, and the unraveling of IN-active structures in fungi. Results obtained from the analysis of various soil and air samples and the presence of new fungal ice active species will be revealed. Thanks for collaboration and support to M.O. Andreae, J.-D. Förster, I. Germann-Müller, L.E. Hanson, S. Lelieveld, J. Odhiambo Obuya, T. Pooya, and C. Ruzene-Nespoli. The Max Planck Society (MPG), Ice Nuclei research UnIT (INUIT), and the German Research Foundation (PO1013/5-1) are acknowledged for financial support. 1. Fröhlich-Nowoisky, J., et al. (2009) Proc. Natl Acad. Sci., 106, 12814-12819 2. Georgakopoulos

  11. Groundwater quality and occurrence and distribution of selected constituents in the Aquia and Upper Patapsco aquifers, Naval Air Station Patuxent River, St. Mary's County, Maryland, July 2008

    USGS Publications Warehouse

    Dieter, Cheryl A.; Campo, Kimberly W.; Baker, Anna C.

    2012-01-01

    The Naval Air Station Patuxent River in southern Maryland has continued to expand in the first decade of the 21st century, contributing to rapid population growth in the surrounding area. The increase in population has caused State and County water managers and others to be concerned about the impact of population growth on the quantity and quality of groundwater supplies. The U.S. Geological Survey has been investigating the groundwater resources of the air station since 1998. As part of that ongoing investigation, groundwater was sampled in 2008 in six wells in the Aquia aquifer and two wells in the Upper Patapsco aquifer in the vicinity of Naval Air Station Patuxent River and Webster Outlying Field. Groundwater samples were analyzed for basic chemistry (field parameters, major ions, and nutrients) as well as several water-quality issues of concern including the occurrence of arsenic and tungsten, and saltwater intrusion. The results of the 2008 groundwater-quality sampling indicate that the overall quality of groundwater in the Aquia aquifer has not changed since 1943; data are too limited to determine if groundwater quality has changed in the Upper Patapsco aquifer. At one well in the Aquia aquifer, the arsenic concentration exceeded the U.S. Environmental Protection Agency standard for drinking water. Arsenic was not detected in samples from the Upper Patapsco aquifer. Tungsten concentrations were detected at low concentrations near the laboratory reporting level in all eight samples. There was no evidence of saltwater intrusion in any of the wells.

  12. Safety Improves Dramatically In Fluor Hanford Soil and Groundwater Remediation Project

    SciTech Connect

    Foster, A.L.; Gerber, M.S.; VonBargen, B.H.

    2008-07-01

    This paper describes dramatic improvements in the safety record of the Soil and Groundwater Remediation Project (SGRP) at the Hanford Site in southeast Washington state over the past four years. During a period of enormous growth in project work and scope, contractor Fluor Hanford reduced injuries, accidents, and other safety-related incidents and enhanced a safety culture that earned the SGRP Star Status in the Department of Energy's (DOE's) Voluntary Protection Program (VPP) in 2007. This paper outlines the complex and multi-faceted work of Fluor Hanford's SGRP and details the steps taken by the project's Field Operations and Safety organizations to improve safety. Holding field safety meetings and walk-downs, broadening safety inspections, organizing employee safety councils, intensively flowing down safety requirements to subcontractors, and adopting other methods to achieve remarkable improvement in safety are discussed. The roles of management, labor and subcontractors are detailed. Finally, SGRP's safety improvements are discussed within the context of overall safety enhancements made by Fluor Hanford in the company's 11 years of managing nuclear waste cleanup at the Hanford Site. (authors)

  13. SAFETY IMPROVES DRAMATICALLY IN FLUOR HANFORD SOIL AND GROUNDWATER REMEDIATION PROJECT

    SciTech Connect

    GERBER MS

    2007-12-05

    This paper describes dramatic improvements in the safety record of the Soil and Groundwater Remediation Project (SGRP) at the Hanford Site in southeast Washington state over the past four years. During a period of enormous growth in project work and scope, contractor Fluor Hanford reduced injuries, accidents, and other safety-related incidents and enhanced a safety culture that earned the SGRP Star Status in the Department of Energy's (DOE's) Voluntary Protection Program (VPP) in 2007. This paper outlines the complex and multi-faceted work of Fluor Hanford's SGRP and details the steps taken by the project's Field Operations and Safety organizations to improve safety. Holding field safety meetings and walkdowns, broadening safety inspections, organizing employee safety councils, intensively flowing down safety requirements to subcontractors, and adopting other methods to achieve remarkable improvement in safety are discussed. The roles of management, labor and subcontractors are detailed. Finally, SGRP's safety improvements are discussed within the context of overall safety enhancements made by Fluor Hanford in the company's 11 years of managing nuclear waste cleanup at the Hanford Site.

  14. Substance-related environmental monitoring strategies regarding soil, groundwater and surface water - an overview.

    PubMed

    Kördel, Werner; Garelick, Hemda; Gawlik, Bernd M; Kandile, Nadia G; Peijnenburg, Willie J G M; Rüdel, Heinz

    2013-05-01

    Substance-related monitoring is an essential tool within environmental risk assessment processes. The soundness of policy decisions including risk management measures is often directly related to the reliability of the environmental monitoring programs. In addition, monitoring programs are required for identifying new and less-investigated pollutants of concern in different environmental media. Scientifically sound and feasible monitoring concepts strongly depend on the aim of the study. The proper definition of questions to be answered is thus of pivotal importance. Decisions on sample handling, storage and the analysis of the samples are important steps for the elaboration of problem-oriented monitoring strategies. The same applies to the selection of the sampling sites as being representative for scenarios to be investigated. These steps may become critical to handle for larger international monitoring programs and thus trigger the quality of their results. This study based on the work of an IUPAC (International Union of Pure and Applied Chemistry) task group addresses different kinds and approaches of substance-related monitoring of different compartments of soil, groundwater and surface water, and discusses their advantages and limitations. Further important aspects are the monitoring across policies and the monitoring data management using information systems.

  15. [Removal mechanism of light non-aqueous phase liquid from soil and groundwater by surfactant].

    PubMed

    Yang, Jian; Chen, Jia-Jun; Lu, Yi

    2009-07-15

    Surfactant increases solubilization of n-hexadecane and reduces interfacial tension between surfactant and n-hexadecane, which are very important for the removal of residual LNAPLs in porous media. After the solubilization of n-hexadecane and interfacial tension between Triton X-100 solution and n-hexadecane were studied through experiments, the forming rule of different states of n-hexadecane were analyzed through equilibrium washing experiment and sand pillar leaching experiment. The experimental results show that: the dissolving ability was proportional to the concentration of Triton X-100 solution, and MSR = 1.680 4 and lgk(mc) = 1.715 8 calculated by solubilization of n-hexadecane when Triton X-100 solution concentration was large than CMC. The interfacial tension was inversely proportional to Triton X-100 solution concentration, and the variation was in accord with Gauss model (R2 = 0.996 4). Dissolved state and free state n-hexadecane had very good corresponding relation with solubilization and reducing interfacial tension respectively. Both solubilization and reducing interfacial tension could remove n-hexadecane from porous media. Reducing interfacial tension increased the flow ability of n-hexadecane effectively, and it removed most of residual n-hexadecane in soil and groundwater remediation.

  16. Coupling ANIMO and MT3DMS for 3D regional-scale modeling of nutrient transport in soil and groundwater

    NASA Astrophysics Data System (ADS)

    Janssen, G.; Del Val Alonso, L.; Groenendijk, P.; Griffioen, J.

    2012-12-01

    We developed an on-line coupling between the 1D/quasi-2D nutrient transport model ANIMO and the 3D groundwater transport model code MT3DMS. ANIMO is a detailed, process-oriented model code for the simulation of nitrate leaching to groundwater, N- and P-loads on surface waters and emissions of greenhouse gasses. It is the leading nutrient fate and transport code in the Netherlands where it is used primarily for the evaluation of fertilization related legislation. In addition, the code is applied frequently in international research projects. MT3DMS is probably the most commonly used groundwater solute transport package worldwide. The on-line model coupling ANIMO-MT3DMS combines the state-of-the-art descriptions of the biogeochemical cycles in ANIMO with the advantages of using a 3D approach for the transport through the saturated domain. These advantages include accounting for regional lateral transport, considering groundwater-surface water interactions more explicitly, and the possibility of using MODFLOW to obtain the flow fields. An additional merit of the on-line coupling concept is that it preserves feedbacks between the saturated and unsaturated zone. We tested ANIMO-MT3DMS by simulating nutrient transport for the period 1970-2007 in a Dutch agricultural polder catchment covering an area of 118 km2. The transient groundwater flow field had a temporal resolution of one day and was calculated with MODFLOW-MetaSWAP. The horizontal resolution of the model grid was 100x100m and consisted of 25 layers of varying thickness. To keep computation times manageable, we prepared MT3DMS for parallel computing, which in itself is a relevant development for a large community of groundwater transport modelers. For the parameterization of the soil, we applied a standard classification approach, representing the area by 60 units with unique combinations of soil type, land use and geohydrological setting. For the geochemical parameterization of the deeper subsurface, however, we

  17. Treatment of Perchlorate-Contaminated Groundwater Using Highly-Selective, Regenerable Anion-Exchange Resins at Edwards Air Force Base

    SciTech Connect

    Gu, B.

    2003-05-30

    Selective ion exchange is one of the most effective treatment technologies for removing low levels of perchlorate (ClO{sub 4}{sup -}) from contaminated water because of its high efficiency without adverse impacts on the water quality caused by adding or removing any chemicals or nutrients. This report summarizes both the laboratory and a field pilot-scale studies to determine the ability and efficiency of the bifunctional synthetic resins to remove ClO{sub 4}{sup -} from the contaminated groundwater at the Edwards Air Force Base in California. Regeneration of the resins after groundwater treatment was also evaluated using the FeCl{sub 3}-HCl regeneration technique recently developed at Oak Ridge National Laboratory. On the basis of this study, the bifunctional resin, D-3696 was found to be highly selective toward ClO{sub 4}{sup -} and performed much better than one of the best commercial nitrate-selective resins (Purolite A-520E) and more than an order of magnitude better than the Purolite A-500 resin (with a relatively low selectivity). At an influent concentration of {approx} 450 {micro}g/L ClO{sub 4}{sup -} in groundwater, the bifunctional resin bed treated {approx} 40,000 empty bed volumes of groundwater before a significant breakthrough of ClO{sub 4}{sup -} occurred. The presence of relatively high concentrations of chloride and sulfate in site groundwater did not appear to affect the ability of the bifunctional resin to remove ClO{sub 4}{sup -}. However, the presence of high iron or iron oxyhydroxides and/or biomass in groundwater caused a significant fouling of the resin beds and greatly influenced the effectiveness in regenerating the resins sorbed with ClO{sub 4}{sup -}. Under such circumstances, a prefilter ({approx} 0.5-1 {micro}m) was found to be necessary to remove these particulates and to reduce the risk of fouling of the resin beds. Without significant fouling, the resin bed could be effectively regenerated by the FeCl{sub 3} displacement technique

  18. Observations on long-term air-soil exchange of organic contaminants.

    PubMed

    Jones, K C

    1994-09-01

    Evidence for long-term changes in the soil composition of selected organic compounds, brought about by exchanges with the atmosphere, is briefly reviewed. In the case of some compounds - such as benzo(a)pyrene and octachlorodibenzo-p-dioxin, soils may be significant long-term environmental sinks for atmospherically-derived material. In other cases - such as phenanthrene and some of the lighter PCBs, de-gassing or volatilisation from soil back to the air can occur under certain conditions. Hence the soil may act as a "short-term" sink, and a potential source to atmosphere. Indeed, for some 'semi-volatile' compounds used in large quantities in the past - such as PCBs, soil outgassing may actually be an extremely important source to contemporary air. Furthermore, soil outgassing from areas of former high use may provide an important driving mechanism for continued "global cycling" of a range of semi-volatile organochlorine compounds.

  19. The groundwater land-surface atmosphere connection: Soil moisture effects on the atmospheric boundary layer in fully-coupled simulations

    NASA Astrophysics Data System (ADS)

    Maxwell, Reed M.; Chow, Fotini Katopodes; Kollet, Stefan J.

    2007-12-01

    This study combines a variably-saturated groundwater flow model and a mesoscale atmospheric model to examine the effects of soil moisture heterogeneity on atmospheric boundary layer processes. This parallel, integrated model can simulate spatial variations in land-surface forcing driven by three-dimensional (3D) atmospheric and subsurface components. The development of atmospheric flow is studied in a series of idealized test cases with different initial soil moisture distributions generated by an offline spin-up procedure or interpolated from a coarse-resolution dataset. These test cases are performed with both the fully-coupled model (which includes 3D groundwater flow and surface water routing) and the uncoupled atmospheric model. The effects of the different soil moisture initializations and lateral subsurface and surface water flow are seen in the differences in atmospheric evolution over a 36-h period. The fully-coupled model maintains a realistic topographically-driven soil moisture distribution, while the uncoupled atmospheric model does not. Furthermore, the coupled model shows spatial and temporal correlations between surface and lower atmospheric variables and water table depth. These correlations are particularly strong during times when the land-surface temperatures trigger shifts in wind behavior, such as during early morning surface heating.

  20. Arsenic contamination of the soil-wheat system irrigated with high arsenic groundwater in the Hetao Basin, Inner Mongolia, China.

    PubMed

    Tong, Junting; Guo, Huaming; Wei, Chao

    2014-10-15

    As one of the most important crop in the world, wheat (Triticum aestivum L.) was irrigated with low As water and high As water. However, little is known about As cycling in the soil-wheat-water system. Two wheat fields (site G and site Y), irrigated with high dissolved As (178 μg L(-1)) groundwater and low dissolved As (8.2 μg L(-1)) surface water, respectively, were systematically sampled in the Hetao Basin, including irrigation water, soils and plants. The annual As (including dissolved As and suspended As) input per m(2) was estimated at 140 and 36.7 mg in site G and site Y, respectively. Topsoils of site G contained relatively higher As content (average 18.8 mg kg(-1)) than those of site Y (13.8 mg kg(-1)). Arsenic content of wheat grains in site G is systematically higher than in the site Y, which were positively correlated with non-specifically sorbed-As and amorphous Fe/Al oxide-bound As in topsoils. Arsenic-contaminated groundwater led to As accumulation in irrigated soils and the increase in As bioavailability, and subsequently resulted in the increase in As content of wheat grain. It suggested that less problematic water resources should be used for wheat irrigation in order to avoid As accumulation in the soil-plant system. PMID:25108250

  1. Arsenic contamination of the soil-wheat system irrigated with high arsenic groundwater in the Hetao Basin, Inner Mongolia, China.

    PubMed

    Tong, Junting; Guo, Huaming; Wei, Chao

    2014-10-15

    As one of the most important crop in the world, wheat (Triticum aestivum L.) was irrigated with low As water and high As water. However, little is known about As cycling in the soil-wheat-water system. Two wheat fields (site G and site Y), irrigated with high dissolved As (178 μg L(-1)) groundwater and low dissolved As (8.2 μg L(-1)) surface water, respectively, were systematically sampled in the Hetao Basin, including irrigation water, soils and plants. The annual As (including dissolved As and suspended As) input per m(2) was estimated at 140 and 36.7 mg in site G and site Y, respectively. Topsoils of site G contained relatively higher As content (average 18.8 mg kg(-1)) than those of site Y (13.8 mg kg(-1)). Arsenic content of wheat grains in site G is systematically higher than in the site Y, which were positively correlated with non-specifically sorbed-As and amorphous Fe/Al oxide-bound As in topsoils. Arsenic-contaminated groundwater led to As accumulation in irrigated soils and the increase in As bioavailability, and subsequently resulted in the increase in As content of wheat grain. It suggested that less problematic water resources should be used for wheat irrigation in order to avoid As accumulation in the soil-plant system.

  2. Studies on the integration of nanofiltration and soil treatment for municipal effluent reclamation as a groundwater supplement.

    PubMed

    Linlin, Wu; Xuan, Zhao; Meng, Zhang

    2010-01-01

    Water shortage leads to increasing attention to artificial groundwater recharge by reclaimed water. An injection well is the most common recharge approach. In this paper, a new kind of integrated technology-short-term vadose soil treatment followed by nanofiltration-is recommended as pretreatment for artificial groundwater recharge by an injection well. Laboratory-scale experiments demonstrate that the short-term vadose soil can remove approximately 30% of the total dissolved organic carbon (DOC) content and 40% of dissolved organic matter with a molecular weight less than 1 kDa. As a compensatory process of soil treatment, nanofiltration offers a favorable desalination and additional organics removal. The removal efficiencies for total dissolved solids and conductivity amount to 45 and 48%, respectively. The residual DOC in the final effluent is below 1.0 mg/L. In addition, short-term vadose soil offers effective elimination of aromatic protein-like and polysaccharide-like substances, which are detected as components of the membrane foulant.

  3. The groundwater-land-surface-atmosphere connection: soil moisture effects on the atmospheric boundary layer in fully-coupled simulations

    SciTech Connect

    Maxwell, R M; Chow, F K; Kollet, S J

    2007-02-02

    This study combines a variably-saturated groundwater flow model and a mesoscale atmospheric model to examine the effects of soil moisture heterogeneity on atmospheric boundary layer processes. This parallel, integrated model can represent spatial variations in land-surface forcing driven by three-dimensional (3D) atmospheric and subsurface components. The development of atmospheric flow is studied in a series of idealized test cases with different initial soil moisture distributions generated by an offline spin-up procedure or interpolated from a coarse-resolution dataset. These test cases are performed with both the fully-coupled model (which includes 3D groundwater flow and surface water routing) and the uncoupled atmospheric model. The effects of the different soil moisture initializations and lateral subsurface and surface water flow are seen in the differences in atmospheric evolution over a 36-hour period. The fully-coupled model maintains a realistic topographically-driven soil moisture distribution, while the uncoupled atmospheric model does not. Furthermore, the coupled model shows spatial and temporal correlations between surface and lower atmospheric variables and water table depth. These correlations are particularly strong during times when the land surface temperatures trigger shifts in wind behavior, such as during early morning surface heating.

  4. Studies on the integration of nanofiltration and soil treatment for municipal effluent reclamation as a groundwater supplement.

    PubMed

    Linlin, Wu; Xuan, Zhao; Meng, Zhang

    2010-01-01

    Water shortage leads to increasing attention to artificial groundwater recharge by reclaimed water. An injection well is the most common recharge approach. In this paper, a new kind of integrated technology-short-term vadose soil treatment followed by nanofiltration-is recommended as pretreatment for artificial groundwater recharge by an injection well. Laboratory-scale experiments demonstrate that the short-term vadose soil can remove approximately 30% of the total dissolved organic carbon (DOC) content and 40% of dissolved organic matter with a molecular weight less than 1 kDa. As a compensatory process of soil treatment, nanofiltration offers a favorable desalination and additional organics removal. The removal efficiencies for total dissolved solids and conductivity amount to 45 and 48%, respectively. The residual DOC in the final effluent is below 1.0 mg/L. In addition, short-term vadose soil offers effective elimination of aromatic protein-like and polysaccharide-like substances, which are detected as components of the membrane foulant. PMID:20112534

  5. Historical changes in air temperature are evident in temperature fluxes measured in the sub-soil.

    NASA Astrophysics Data System (ADS)

    Fraser, Fiona; McCormick, Benjamin; Hallett, Paul; Wookey, Philip; Hopkins, David

    2013-04-01

    Warming trends in soil temperature have implications for a plethora of soil processes, including exacerbated climate change through the net release of greenhouse gases. Whereas long-term datasets of air temperature changes are abundant, a search of scientific literature reveals a lack of information on soil temperature changes and their specific consequences. We analysed five long-term data series collected in the UK (Dundee and Armagh) and Canada (Charlottetown, Ottawa and Swift Current). They show that the temperatures of soils at 5 - 20 cm depth, and sub-soils at 30 - 150 cm depth, increased in line with air temperature changes over the period 1958 - 2003. Differences were found, however, between soil and air temperatures when data were sub-divided into seasons. In spring, soil temperature warming ranged from 0.19°C at 30 cm in Armagh to 4.30°C at 50 cm in Charlottetown. In summer, however, the difference was smaller and ranged from 0.21°C at 10 cm in Ottawa to 3.70°C at 50 cm in Charlottetown. Winter temperatures were warmer in soil and ranged from 0.45°C at 5 cm in Charlottetown to 3.76°C at 150 cm in Charlottetown. There were significant trends in changes to soil temperature over time, whereas air temperature trends tended only to be significant in winter (changes range from 1.27°C in Armagh to 3.35°C in Swift Current). Differences in the seasonal warming patterns between air and soil temperatures have potential implications for the parameterization of models of biogeochemical cycling.

  6. CO2 CH4 flux Air temperature Soil temperature and Soil moisture, Barrow, Alaska 2013 ver. 1

    SciTech Connect

    Margaret Torn

    2015-01-14

    This dataset consists of field measurements of CO2 and CH4 flux, as well as soil properties made during 2013 in Areas A-D of Intensive Site 1 at the Next-Generation Ecosystem Experiments (NGEE) Arctic site near Barrow, Alaska. Included are i) measurements of CO2 and CH4 flux made from June to September (ii) Calculation of corresponding Gross Primary Productivity (GPP) and CH4 exchange (transparent minus opaque) between atmosphere and the ecosystem (ii) Measurements of Los Gatos Research (LGR) chamber air temperature made from June to September (ii) measurements of surface layer depth, type of surface layer, soil temperature and soil moisture from June to September.

  7. Comparison of Groundwater Recharge under Irrigated Cropland versus Natural Land in Clayey Soils under Mediterranean Climate in Israel

    NASA Astrophysics Data System (ADS)

    Kurtzman, D.; Scanlon, B. R.

    2010-12-01

    Land use change from natural ecosystems to cropland influences groundwater recharge, including water quantity and quality. Soil core samples (0-11 m depth) from 6 boreholes beneath irrigated cropland (field crops) and 2 boreholes beneath natural ecosystems, in clayey soils undelain by sands, were analyzed for grain-size distribution, water content, and water-extractable Cl. Chloride mass balance and numerical 1D unsaturated zone flow and transport modeling were used for assessing average and transient recharge fluxes, and for testing matrix versus preferential flow hypotheses. Water contents under irrigated cropland are significantly higher than those found under natural land with similar grain-size distribution. Pore water Cl concentrations in deep unsaturated zone under irrigated cropland (900-2000 mg/L) are similar to recent local groundwater Cl and significantly lower than pore water Cl in deep unsaturated zone under natural ecosystems (3000 and 6000 mg/L, Figure 1). Calibrated models’ recharge rates through the soil matrix are much higher under irrigated cropland (90-230 mm/yr) than under natural ecosystems (0-2 mm/yr) and are consistent with groundwater balance estimates of average recharge (110-160 mm/yr). In contrast, matrix-recharge rates under natural ecosystems are much lower than those based on groundwater balance (50-80 mm/yr). While matrix flow in the unsaturated zone under irrigated cropland explains both groundwater and unsaturated zone observations, under natural land, preferential flow paths are needed for supporting unsaturated zone observations and pre-extensive-cultivation groundwater Cl concentrations. Plowing and irrigation prevent development of crack networks and promote matrix percolation through the clay, which flushes salts from previously immobile unsaturated zone pore-water. After flushing is completed, water recharge fluxes are correlated to precipitation of the recent and previous year, while the salinity of recharging water

  8. Experimental study on evaporation from seasonally frozen soils under various water, solute and groundwater conditions in Inner Mongolia, China

    NASA Astrophysics Data System (ADS)

    Wu, Mousong; Huang, Jiesheng; Wu, Jingwei; Tan, Xiao; Jansson, Per-Erik

    2016-04-01

    Soil freezing and thawing significantly impact water balance in cold regions. To improve estimations of evaporation from seasonally frozen and saline soils, field experiments representing various water and solute conditions were conducted during a 5-month-period in Inner Mongolia, China. A mass balance method was used to estimate evaporation from frost tubes (5.5 × 300 cm) with treatments combining three solute contents (0.2%, 0.4%, and 0.6% g g-1 dry soil) with three initial groundwater table depth (GWTDs) (2.0, 1.5, and 1.0 m). The dynamics of water, heat and solute transport in the frost tubes and in field plots were also investigated. Seasonal changes in evaporation rates were observed during soil freezing/thawing periods. Low evaporation rates were maintained when the soil was deeply frozen (e.g., in P3), and relatively higher values occurred at the beginning and the end of the experiments (e.g., in P1 and P5). The cumulative evaporation amount increased with an increase in initial solute content and declined with a lowering of the initial GWTDs. Solute accumulation with water in the surface layer during freezing decreased the osmotic potential in soil, resulting in obvious freezing point depressions and higher liquid water contents in the uppermost layer of soil. During the soil thawing periods, no evidence of any control of water availability on evaporation was noticed, although the surface soil contained large amounts of water. This study has led to an improved understanding of the coupled effects of water, heat and solute on evaporation from seasonally frozen saline soils and also has important implications for water and energy balance studies in cold regions.

  9. CONTROL OF AROMATIC WASTE AIR STREAMS BY SOIL BIOREACTORS

    EPA Science Inventory

    Three soils were examined for the ability to degrade hydrocarbon vapors of benzene, toluene, ethylbenzene, and o-xylene (BTEX). Each of these compounds are major aromatic constituents of gasolines. The soils examined were Rubicon Sand from Traverse City, Michigan, Durant Loam fro...

  10. Removal of volatile and semivolatile organic contamination from soil by air and steam flushing.

    PubMed

    Sleep, B E; McClure, P D

    2001-07-01

    A soil core, obtained from a contaminated field site, contaminated with a mixture of volatile and semivolatile organic compounds (VOC and SVOC) was subjected to air and steam flushing. Removal rates of volatile and semivolatile organic compounds were monitored during flushing. Air flushing removed a significant portion of the VOC present in the soil, but a significant decline in removal rate occurred due to decreasing VOC concentrations in the soil gas phase. Application of steam flushing after air flushing produced a significant increase in contaminant removal rate for the first 4 to 5 pore volumes of steam condensate. Subsequently, contaminant concentrations decreased slowly with additional pore volumes of steam flushing. The passage of a steam volume corresponding to 11 pore volumes of steam condensate reduced the total VOC concentration in the soil gas (at 20 degrees C) by a factor of 20 to 0.07 mg/l. The corresponding total SVOC concentration in the condensate declined from 11 to 3 mg/l. Declines in contaminant removal rates during both air and steam flushing indicated rate-limited removal consistent with the persistence of a residual organic phase, rate-limited desorption, or channeling. Pressure gradients were much higher for steam flushing than for air flushing. The magnitude of the pressure gradients encountered during steam flushing for this soil indicates that, in addition to rate-limited contaminant removal, the soil permeability (2.1 x 10(-9) cm2) would be a limiting factor in the effectiveness of steam flushing. PMID:11475159

  11. Distribution, correlation, and source apportionment of selected metals in tannery effluents, related soils, and groundwater--a case study from Multan, Pakistan.

    PubMed

    Tariq, Saadia R; Shaheen, N; Khalique, A; Shah, Munir H

    2010-07-01

    In order to study the distribution, correlation, and apportionment of selected metals, the tannery effluent, related soil, and groundwater samples were collected from Multan, Pakistan, and analyzed on flame atomic absorption spectrophotometer. Among the selected metals, Na, Ca, K, Cr, and Mg revealed dominant concentrations with average values of 5,499, 945, 565, 209, and 107 mg/L and 2,634, 330, 484, 14.1, and 60.5 mg/L in the effluents and groundwater, respectively, whereas the mean metal levels in soil samples were 10,026, 6,726, 9,242, 476, and 9,857 mg/kg. Overall, the mean metal concentrations in the tannery effluents, groundwater, and related soils reveal following order, respectively: Na > Ca > K > Cr > Mg > Ni > Fe > Zn > Co > Pb > Mn > Cd; Na > K > Ca > Mg > Cr > Zn > Ni > Pb > Fe > Co > Mn > Cd; Na > Mg > K > Ca > Cr > Co > Ni > Fe > Pb > Mn > Zn > Cd. Generally, the metal distribution in tannery effluents, soils, and groundwater was found to be random as evidenced by large differences between mean and median values as well as considerably higher standard deviation and skewness values. The selected metal data were also subjected to correlation study to investigate the covariation of metal levels in the three media. The source apportionment of the metal data in the effluents, soils, and groundwater was carried out using principal component analysis in addition to basic statistical and correlation analyses. The source apportionment studies evidenced the gross contamination of groundwater and soils in the vicinity of tanning industrial units in Multan. The current mean metal levels in the soil and groundwater were found to be considerably higher compared with the background concentration levels and WHO guideline values.

  12. Linking soil water balance and water age with leaching of nitrate to groundwater in an agricultural setting

    NASA Astrophysics Data System (ADS)

    Sigler, W.; Ewing, S. A.; Payn, R. A.; Jones, C. A.; Weissmann, G. S.

    2013-12-01

    The effects of land management on groundwater chemistry are often poorly understood due to uncertainties about residence times of water and solutes in the unsaturated and the saturated zones. In central Montana, a strath terrace mantled with 20-100 cm of loess-derived clay loam is composed of 5-10 meters of gravel hosting a shallow aquifer overlying shale. The landform is isolated from mountain front stream recharge and drained by springs at the gravel/shale interface surrounding the terrace. Ninety three percent of the terrace surface is cultivated, predominantly for production of small grains. A typical cropping system on the terrace is a three year rotation of winter wheat, spring wheat or barley, and fallow, where each phase represents a different regime of evapotranspiration, recharge, fertilizer application, mineralization and nitrate leaching to groundwater. Age of water in discharge from the perched aquifer in the gravel can potentially be characterized by monitoring springs and streams that are ultimately sourced by infiltration and recharge across the terrace. Work presented here couples a simple daily soil water balance model with ground and surface water chemistry to infer travel times through the unsaturated and saturated zones. These results are evaluated against estimates of groundwater age derived from pool turnover time calculations, finite difference groundwater flow modeling, and use of chemical age tracers.

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

    PubMed

    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

  14. Effects of land cover on water table, soil moisture, evapotranspiration, and groundwater recharge: A Field observation and analysis

    USGS Publications Warehouse

    Zhang, Y.-K.; Schilling, K.E.

    2006-01-01

    The effects of land cover on water table, soil moisture, evapotranspiration, and groundwater recharge were studied with water level measurements collected from two monitoring wells over a period of 122 days. The two wells were installed under similar conditions except that one was drilled on the east side of a creek which was covered with grass, and the other on the west side of the creek which was burned into a bare ground. Substantial differences in water level fluctuations were observed at these two wells. The water level in the east grass (EG) well was generally lower and had much less response to rainfall events than the west no-grass (WNG) well. Grass cover lowered the water table, reduced soil moisture through ET losses, and thus reduced groundwater recharge. The amount of ET by the grass estimated with a water table recession model decreased exponentially from 7.6 mm/day to zero as the water table declined from near the ground surface to 1.42 m below the ground surface in 33 days. More groundwater recharge was received on the WNG side than on the EG side following large rainfall events and by significant slow internal downward drainage which may last many days after rainfall. Because of the decreased ET and increased R, significantly more baseflow and chemical loads may be generated from a bare ground watershed compared to a vegetated watershed. ?? 2005 Elsevier Ltd All rights reserved.

  15. Scale Dependence of Soil Permeability to Air: Measurement Method and Field Investigation

    SciTech Connect

    Garbesi, K.; Sextro, R.G.; Robinson, Arthur L.; Wooley, J.D.; Owens, J.A.; Nazaroff, W.W.

    1995-11-01

    This work investigates the dependence soil air-permeability on sampling scale in near-surface unsaturated soils. A new dual-probe dynamic pressure technique was developed to measure permeability in situ over different length scales and different spatial orientations in the soil. Soils at three sites were studied using the new technique. Each soil was found to have higher horizontal than vertical permeability. Significant scale dependence of permeability was also observed at each site. Permeability increased by a factor of 20 as sampling scale increased from 0.1 to 2 m in a sand soil vegetated with dry grass, and by a factor of 15 as sampling scale increased from 0.1 to 3.5 m in a sandy loam with mature Coast Live Oak trees (Quercus agrifolia). The results indicate that standard methods of permeability assessment can grossly underestimate advective transport of gas-phase contaminants through soils.

  16. Treatment of MTBE by air stripping, carbon adsorption, and advanced oxidation: technical and economic comparison for five groundwaters.

    PubMed

    Sutherland, J; Adams, C; Kekobad, J

    2004-01-01

    An investigation was made of the treatability of methyl tert-butyl ether (MTBE) in five groundwaters with highly varied water quality characteristics. Air stripping, granular activated carbon (GAC) adsorption, and the O(3)/H(2)O(2) and UV/H(2)O(2) advanced oxidation processes were compared in a mobile water treatment pilot plant under a variety of process conditions. Air stripping was shown to have the lower unit treatment costs for higher flowrates (i.e., 3800L/min), although relatively tall towers were required for greater treatment requirements. At low flowrates (i.e., 38L/min), advanced oxidation provided the lowest treatment costs for four of five waters (but was ineffective for a high chemical oxygen demand water). Both the O(3)/H(2)O(2) and UV/H(2)O(2) processes were more efficient at pH 7 versus 9 due in part to increased scavenging at higher pH. GAC was examined using rapid small-scale column tests (RSSCT). GAC was effective at most conditions, although it was also the most costly alternative for most waters. The results of this study can help to provide specific guidance into process selection for treating MTBE in contaminated groundwaters.

  17. Transfers of iodine in the soil-plant-air system: Solid-liquid partitioning, migration, plant uptake adn volatilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Human exposure to soil iodine depends upon the partitioning of the iodine into the, mobile, liquid and gaseous soil phases. From the liquid phase, iodine can be transported into surface- and ground-waters, plant roots, and, consequently, into the human diet. From the gaseous phase, iodine can be tra...

  18. Analysis of the NASA AirMOSS Root Zone Soil Water and Soil Temperature from Three North American Ecosystems

    NASA Astrophysics Data System (ADS)

    Hagimoto, Y.; Cuenca, R. H.

    2015-12-01

    Root zone soil water and temperature are controlling factors for soil organic matter accumulation and decomposition which contribute significantly to the CO2 flux of different ecosystems. An in-situ soil observation protocol developed at Oregon State University has been deployed to observe soil water and temperature dynamics in seven ecological research sites in North America as part of the NASA AirMOSS project. Three instrumented profiles defining a transect of less than 200 m are installed at each site. All three profiles collect data for in-situ water and temperature dynamics employing seven soil water and temperature sensors installed at seven depth levels and one infrared surface temperature sensor monitoring the top of the profile. In addition, two soil heat flux plates and associated thermocouples are installed at one of three profiles at each site. At each profile, a small 80 cm deep access hole is typically made, and all below ground sensors are installed into undisturbed soil on the side of the hole. The hole is carefully refilled and compacted so that root zone soil water and temperature dynamics can be observed with minimum site disturbance. This study focuses on the data collected from three sites: a) Tonzi Ranch, CA; b) Metolius, OR and c) BERMS Old Jack Pine Site, Saskatchewan, Canada. The study describes the significantly different seasonal root zone water and temperature dynamics under the various physical and biological conditions at each site. In addition, this study compares the soil heat flux values estimated by the standard installation using the heat flux plates and thermocouples installed near the surface with those estimated by resolving the soil heat storage based on the soil water and temperature data collected over the total soil profile.

  19. Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Seuntjens, P.; Joris, I.; Boënne, W.; Van Hoey, S.; Campling, P.; Cornelis, W. M.

    2015-07-01

    Monitoring and modeling tools may improve irrigation strategies in precision agriculture. We used non-invasive soil moisture monitoring, a crop growth and a soil hydrological model to predict soil-water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. The sensitivity of the model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed. Free drainage and incremental constant head conditions was implemented in a lower boundary sensitivity analysis. A time-dependent sensitivity analysis showed that changes in soil water content are mainly affected by the soil saturated hydraulic conductivity Ks and the Mualem-van Genuchten retention curve shape parameters n and α. Results further showed that different parameter optimization strategies (two-, three-, four- or six-parameter optimizations) did not affect the calculated water stress and water content as significantly as does the bottom boundary. For this case, a two-parameter scenario, where Ks was optimized for each layer under the condition of a constant groundwater depth at 135-140 cm, performed best. A larger yield reduction, and a larger number and longer duration of stress conditions occurred in the free drainage condition as compared to constant boundary conditions. Numerical results showed that optimal irrigation scheduling using the aforementioned water stress calculations can save up to 12-22 % irrigation water as compared to the current irrigation regime. This resulted in a yield increase of 4.5-6.5 %, simulated by crop growth model.

  20. Using Nitrogen and Oxygen Isotope Compositions of Nitrate to Distinguish Contaminant Sources in Hanford Soil and Groundwater

    SciTech Connect

    Conrad, Mark; Bill, Markus

    2008-08-01

    The nitrogen ({delta}{sup 15}N) and oxygen ({delta}{sup 18}O) isotopic compositions of nitrate in the environment are primarily a function of the source of the nitrate. The ranges of isotopic compositions for nitrate resulting from common sources are outlined in Figure 1 from Kendall (1998). As noted on Figure 1, processes such as microbial metabolism can modify the isotopic compositions of the nitrate, but the effects of these processes are generally predictable. At Hanford, nitrate and other nitrogenous compounds were significant components of most of the chemical processes used at the site. Most of the oxygen in nitrate chemicals (e.g., nitric acid) is derived from atmospheric oxygen, giving it a significantly higher {delta}{sup 18}O value (+23.5{per_thousand}) than naturally occurring nitrate that obtains most of its oxygen from water (the {delta}{sup 18}O of Hanford groundwater ranges from -14{per_thousand} to -18{per_thousand}). This makes it possible to differentiate nitrate from Hanford site activities from background nitrate at the site (including most fertilizers that might have been used prior to the Department of Energy plutonium production activities at the site). In addition, the extreme thermal and chemical conditions that occurred during some of the waste processing procedures and subsequent waste storage in select single-shell tanks resulted in unique nitrate isotopic compositions that can be used to identify those waste streams in soil and groundwater at the site (Singleton et al., 2005; Christensen et al., 2007). This report presents nitrate isotope data for soil and groundwater samples from the Hanford 200 Areas and discusses the implications of that data for potential sources of groundwater contamination.

  1. Perennial filter strips reduce nitrate levels in soil and shallow groundwater after grassland-to-cropland conversion.

    PubMed

    Zhou, Xiaobo; Helmers, Matthew J; Asbjornsen, Heidi; Kolka, Randy; Tomer, Mark D

    2010-01-01

    Many croplands planted to perennial grasses under the Conservation Reserve Program are being returned to crop production, and with potential consequences for water quality. The objective of this study was to quantify the impact of grassland-to-cropland conversion on nitrate-nitrogen (NO3-N) concentrations in soil and shallow groundwater and to assess the potential for perennial filter strips (PFS) to mitigate increases in NO3-N levels. The study, conducted at the Neal Smith National Wildlife Refuge (NSNWR) in central Iowa, consisted of a balanced incomplete block design with 12 watersheds and four watershed-scale treatments having different proportions and topographic positions of PFS planted in native prairie grasses: 100% rowcrop, 10% PFS (toeslope position), 10% PFS (distributed on toe and as contour strips), and 20 PFS (distributed on toe and as contour strips). All treatments were established in fall 2006 on watersheds that were under bromegrass (Bromus L.) cover for at least 10 yr. Nonperennial areas were maintained under a no-till 2-yr corn (Zea mays L.)--soybean [Glycine max. (L.) Merr.] rotation since spring 2007. Suction lysimeter and shallow groundwater wells located at upslope and toeslope positions were sampled monthly during the growing season to determine NO3-N concentration from 2005 to 2008. The results indicated significant increases in NO3-N concentration in soil and groundwater following grassland-to-cropland conversion. Nitrate-nitrogen levels in the vadose zone and groundwater under PFS were lower compared with 100% cropland, with the most significant differences occurring at the toeslope position. During the years following conversion, PFS mitigated increases in subsurface nitrate, but long-term monitoring is needed to observe and understand the full response to land-use conversion.

  2. Perennial filter strips reduce nitrate levels in soil and shallow groundwater after grassland-to-cropland conversion.

    PubMed

    Zhou, Xiaobo; Helmers, Matthew J; Asbjornsen, Heidi; Kolka, Randy; Tomer, Mark D

    2010-01-01

    Many croplands planted to perennial grasses under the Conservation Reserve Program are being returned to crop production, and with potential consequences for water quality. The objective of this study was to quantify the impact of grassland-to-cropland conversion on nitrate-nitrogen (NO3-N) concentrations in soil and shallow groundwater and to assess the potential for perennial filter strips (PFS) to mitigate increases in NO3-N levels. The study, conducted at the Neal Smith National Wildlife Refuge (NSNWR) in central Iowa, consisted of a balanced incomplete block design with 12 watersheds and four watershed-scale treatments having different proportions and topographic positions of PFS planted in native prairie grasses: 100% rowcrop, 10% PFS (toeslope position), 10% PFS (distributed on toe and as contour strips), and 20 PFS (distributed on toe and as contour strips). All treatments were established in fall 2006 on watersheds that were under bromegrass (Bromus L.) cover for at least 10 yr. Nonperennial areas were maintained under a no-till 2-yr corn (Zea mays L.)--soybean [Glycine max. (L.) Merr.] rotation since spring 2007. Suction lysimeter and shallow groundwater wells located at upslope and toeslope positions were sampled monthly during the growing season to determine NO3-N concentration from 2005 to 2008. The results indicated significant increases in NO3-N concentration in soil and groundwater following grassland-to-cropland conversion. Nitrate-nitrogen levels in the vadose zone and groundwater under PFS were lower compared with 100% cropland, with the most significant differences occurring at the toeslope position. During the years following conversion, PFS mitigated increases in subsurface nitrate, but long-term monitoring is needed to observe and understand the full response to land-use conversion. PMID:21284298

  3. Shallow groundwater and cultivated soil suitability assessments with respect to heavy metal content in the Köprübaşi U mineralization area (Manisa, Turkey).

    PubMed

    Kaçmaz, Hülya; Eran Nakoman, M

    2010-07-01

    Shallow groundwater and cultivated soil samples were collected from the area within Köprübaşi U mineralization and analyzed to determine U and selected heavy metals (Fe, Mn, Cu, As, Pb, Zn, Cr, Co and Ba). After this, the suitability of the shallow groundwater and soil samples were evaluated for irrigation, livestock watering and agricultural use, respectively. One groundwater sample (4) showed Mn-concentration of 112.6, exceeding the FAO (Ayers and Westcot 1985) livestock drinking limit (50 microg/l). Nevertheless, the amount of heavy metals including Fe, Cu, As, Pb, Zn, Cr and Co in groundwater is not high for irrigation and livestock drinking water standards cited by the FAO (Ayers and Westcot 1985). On the other hand, all cultivated soil samples have higher uranium concentrations than the typical concentration of natural uranium in soil (ATSDR 1999). The majority of the cultivated soil samples showed higher concentrations than the values for heavy metals (Fe, Mn, Cu, As, Pb, Zn, Cr, Co, Ba) found in normal soils of the world (Connor and Shacklette 1975). However, according to G.L.C guidelines, these soils are classified as uncontaminated with Mn, Cu, Pb, Zn and Cr, slightly contaminated with Ba and As.

  4. Simplified continuous simulation model for investigating effects of controlled drainage on long-term soil moisture dynamics with a shallow groundwater table.

    PubMed

    Sun, Huaiwei; Tong, Juxiu; Luo, Wenbing; Wang, Xiugui; Yang, Jinzhong

    2016-08-01

    Accurate modeling of soil water content is required for a reasonable prediction of crop yield and of agrochemical leaching in the field. However, complex mathematical models faced the difficult-to-calibrate parameters and the distinct knowledge between the developers and users. In this study, a deterministic model is presented and is used to investigate the effects of controlled drainage on soil moisture dynamics in a shallow groundwater area. This simplified one-dimensional model is formulated to simulate soil moisture in the field on a daily basis and takes into account only the vertical hydrological processes. A linear assumption is proposed and is used to calculate the capillary rise from the groundwater. The pipe drainage volume is calculated by using a steady-state approximation method and the leakage rate is calculated as a function of soil moisture. The model is successfully calibrated by using field experiment data from four different pipe drainage treatments with several field observations. The model was validated by comparing the simulations with observed soil water content during the experimental seasons. The comparison results demonstrated the robustness and effectiveness of the model in the prediction of average soil moisture values. The input data required to run the model are widely available and can be measured easily in the field. It is observed that controlled drainage results in lower groundwater contribution to the root zone and lower depth of percolation to the groundwater, thus helping in the maintenance of a low level of soil salinity in the root zone. PMID:27126870

  5. The influence of nitrate leaching through unsaturated soil on groundwater pollution in an agricultural area of the Basque country: a case study.

    PubMed

    Pérez, José Miguel Sánchez; Antiguedad, Iñaki; Arrate, Iñaki; García-Linares, Cristina; Morell, Ignacio

    2003-12-30

    The average nitrate concentration in the groundwater of the Vitoria-Gasteiz (Basque Country) quaternary aquifer rose from 50 mg NO3-/l during 1986 to over 200 mg/l in 1995, which represents an increase of some 20 mg NO3-/l per year. From 1995 to 2002, the nitrate concentration of the groundwater slightly decreased. Nitrate groundwater pollution during the period 1986-1993 was the result of the abusive use of fertilizers and of the modification in the recharge patterns of the aquifer from surface water sources. From 1993 onwards, apart from a possible rationalization in fertilizer use, the change in the origin of water for irrigation and wetland restoration (water is taken now from artificial pools outside the quaternary aquifer) must be explained in order to account for the observed decrease in nitrate concentration in the groundwater. The water of the aquifer and of the unsaturated zone were studied in two experimental plots (one of them cultivated and the other uncultivated) for 18 months (January 1993-June 1994), during the period of maximum contamination, to evaluate the effect of fertilizers on soil water and on the water in the saturated zone. The soil water was sampled using soil lysimeters at various depths. The volumetric water content of the soil was measured at the same depths using time domain reflectrometry (TDR) probes. Samples of groundwater were taken from a network of wells on the aquifer scale, two located close to the two experimental plots. The temporal evolution of nitrate concentrations in soil solutions depends on the addition of fertilizers and on soil nitrate leaching by rain. During episodes of intense rain (>50 mm in a day), the groundwater deposits are recharged with water coming from the leaching of interstitial soil solutions, causing an increase in the groundwater nitrate concentrations. The mass of nitrate leached from the cultivated zone is five times higher than that of the nitrate leached from the uncultivated zone (1147 kg NO3

  6. Natural ³⁷Ar concentrations in soil air: implications for monitoring underground nuclear explosions.

    PubMed

    Riedmann, Robin A; Purtschert, Roland

    2011-10-15

    For on-site inspections (OSI) under the Comprehensive Nuclear-Test-Ban Treaty (CTBT) measurement of the noble gas ³⁷Ar is considered an important technique. ³⁷Ar is produced underground by neutron activation of Calcium by the reaction ⁴⁰Ca(n,α)³⁷Ar. The naturally occurring equilibrium ³⁷Ar concentration balance in soil air is a function of an exponentially decreasing production rate from cosmic ray neutrons with increasing soil depth, diffusive transport in the soil air, and radioactive decay (T(1/2): 35 days). In this paper for the first time, measurements of natural ³⁷Ar activities in soil air are presented. The highest activities of ~100 mBq m⁻³ air are 2 orders of magnitude larger than in the atmosphere and are found in 1.5-2.5 m depth. At depths > 8 m ³⁷Ar activities are < 20 mBq m⁻³ air. After identifying the main ³⁷Ar production and gas transport factors the expected global activity range distribution of ³⁷Ar in shallow subsoil (0.7 m below the surface) was estimated. In high altitude soils, with large amounts of Calcium and with low gas permeability, ³⁷Ar activities may reach values up to 1 Bq m⁻³.

  7. Decomposition Odour Profiling in the Air and Soil Surrounding Vertebrate Carrion

    PubMed Central

    2014-01-01

    Chemical profiling of decomposition odour is conducted in the environmental sciences to detect malodourous target sources in air, water or soil. More recently decomposition odour profiling has been employed in the forensic sciences to generate a profile of the volatile organic compounds (VOCs) produced by decomposed remains. The chemical profile of decomposition odour is still being debated with variations in the VOC profile attributed to the sample collection technique, method of chemical analysis, and environment in which decomposition occurred. To date, little consideration has been given to the partitioning of odour between different matrices and the impact this has on developing an accurate VOC profile. The purpose of this research was to investigate the decomposition odour profile surrounding vertebrate carrion to determine how VOCs partition between soil and air. Four pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their odour profile monitored over a period of two months. Corresponding control sites were also monitored to determine the VOC profile of the surrounding environment. Samples were collected from the soil below and the air (headspace) above the decomposed remains using sorbent tubes and analysed using gas chromatography-mass spectrometry. A total of 249 compounds were identified but only 58 compounds were common to both air and soil samples. This study has demonstrated that soil and air samples produce distinct subsets of VOCs that contribute to the overall decomposition odour. Sample collection from only one matrix will reduce the likelihood of detecting the complete spectrum of VOCs, which further confounds the issue of determining a complete and accurate decomposition odour profile. Confirmation of this profile will enhance the performance of cadaver-detection dogs that are tasked with detecting decomposition odour in both soil and air to locate victim remains. PMID:24740412

  8. Decomposition odour profiling in the air and soil surrounding vertebrate carrion.

    PubMed

    Forbes, Shari L; Perrault, Katelynn A

    2014-01-01

    Chemical profiling of decomposition odour is conducted in the environmental sciences to detect malodourous target sources in air, water or soil. More recently decomposition odour profiling has been employed in the forensic sciences to generate a profile of the volatile organic compounds (VOCs) produced by decomposed remains. The chemical profile of decomposition odour is still being debated with variations in the VOC profile attributed to the sample collection technique, method of chemical analysis, and environment in which decomposition occurred. To date, little consideration has been given to the partitioning of odour between different matrices and the impact this has on developing an accurate VOC profile. The purpose of this research was to investigate the decomposition odour profile surrounding vertebrate carrion to determine how VOCs partition between soil and air. Four pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their odour profile monitored over a period of two months. Corresponding control sites were also monitored to determine the VOC profile of the surrounding environment. Samples were collected from the soil below and the air (headspace) above the decomposed remains using sorbent tubes and analysed using gas chromatography-mass spectrometry. A total of 249 compounds were identified but only 58 compounds were common to both air and soil samples. This study has demonstrated that soil and air samples produce distinct subsets of VOCs that contribute to the overall decomposition odour. Sample collection from only one matrix will reduce the likelihood of detecting the complete spectrum of VOCs, which further confounds the issue of determining a complete and accurate decomposition odour profile. Confirmation of this profile will enhance the performance of cadaver-detection dogs that are tasked with detecting decomposition odour in both soil and air to locate victim remains.

  9. An investigation of groundwater organics, soil minerals, and activated carbon on the complexation, adsorption, and separation of technetium-99

    SciTech Connect

    Gu, B.; Dowlen, K.E.

    1996-01-01

    This report summarizes studies on the interactions of technetium-99 (Tc) with different organic compounds and soil minerals under both oxidizing and reducing conditions. The report is divided into four parts and includes (1) effect of natural organic matter (NOM) on the complexation and solubility of Tc, (2) complexation between Tc and trichloroethylene (TCE) in aqueous solutions, (3) adsorption of Tc on soil samples from Paducah Gaseous Diffusion Plant (PGDP), and (4) adsorption and separation of Tc on activated carbon. Various experimental techniques were applied to characterize and identify Tc complexation with organic compounds and TCE, including liquid-liquid extraction, membrane filtration, size exclusion, and gel chromatography. Results indicate, within the experimental error, Tc (as pertechnetate, TcO{sub 4}) did not appear to form complexes with groundwater or natural organic matter under both atmospheric and reducing conditions. However, Tc can form complexes with certain organic compounds or specific functional groups such as salicylate. Tc did not appear to form complexes with TCE in aqueous solution.Both liquid-liquid extraction and high performance liquid chromatography (HPLC) gave no indication Tc was complexed with TCE. The correlations between Tc and TCE concentrations in monitoring wells at PGDP may be a coincidence because TCE was commonly used as a decontamination reagent. Once TCE and Tc entered the groundwater, they behaved similarly because both TcO{sub 4}{sup {minus}} and TCE are poorly adsorbed by soils. An effective remediation technique to remove TcO{sub 4}{sup {minus}} from PGDP contaminated groundwater is needed. One possibility is the use of an activated carbon adsorption technique developed in this study.

  10. Colonization and community structure of root-associated microorganisms of Sabina vulgaris with soil depth in a semiarid desert ecosystem with shallow groundwater.

    PubMed

    Taniguchi, Takeshi; Usuki, Hiroyuki; Kikuchi, Junichi; Hirobe, Muneto; Miki, Naoko; Fukuda, Kenji; Zhang, Guosheng; Wang, Linhe; Yoshikawa, Ken; Yamanaka, Norikazu

    2012-08-01

    Arbuscular mycorrhizal fungi (AMF) have been observed in deep soil layers in arid lands. However, change in AMF community structure with soil depth and vertical distributions of the other root-associated microorganisms are unclear. Here, we examined colonization by AMF and dark septate fungi (DSF), as well as the community structure of AMF and endophytic fungi (EF) and endophytic bacteria (EB) in association with soil depth in a semiarid desert with shallow groundwater. Roots of Sabina vulgaris and soils were collected from surface to groundwater level at 20-cm intervals. Soil chemistry (water content, total N, and available P) and colonization of AMF and DSF were measured. Community structures of AMF, EF, and EB were examined by terminal restriction fragment length polymorphism analysis. AMF colonization decreased with soil depth, although it was mostly higher than 50%. Number of AMF phylotypes decreased with soil depth, but more than five phylotypes were observed at depths up to 100 cm. Number of AMF phylotypes had a significant and positive relationship with soil moisture level within 0-15% of soil water content. DSF colonization was high but limited to soil surface. Number of phylotypes of EF and EB were diverse even in deep soil layers, and the community composition was associated with the colonization and community composition of AMF. This study indicates that AMF species richness in roots decreases but is maintained in deep soil layers in semiarid regions, and change in AMF colonization and community structure associates with community structure of the other root-associated microorganisms.

  11. Coal mining activities change plant community structure due to air pollution and soil degradation.

    PubMed

    Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth

    2014-10-01

    The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. Air monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient air, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to air pollution and altered soil characteristics.

  12. Assessment of groundwater, soil-gas, and soil contamination at the Vietnam Armor Training Facility, Fort Gordon, Georgia, 2009-2010

    USGS Publications Warehouse

    Guimaraes, Wladmir B.; Falls, W. Fred; Caldwell, Andral W.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2011-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the groundwater, soil gas, and soil for contaminants at the Vietnam Armor Training Facility (VATF) at Fort Gordon, from October 2009 to September 2010. The assessment included the detection of organic compounds in the groundwater and soil gas, and inorganic compounds in the soil. In addition, organic contaminant assessment included organic compounds classified as explosives and chemical agents in selected areas. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Four passive samplers were deployed in groundwater wells at the VATF in Fort Gordon. Total petroleum hydrocarbons were detected above the method detection level at all four wells. The only other volatile organic compounds detected above their method detection level were undecane and pentadecane, which were detected in two of the four wells sampled. Soil-gas samplers were deployed at 72 locations in a grid pattern across the VATF. Total petroleum hydrocarbons were detected in 71 of the 72 samplers (one sampler was destroyed in the field and not analyzed) at levels above the method detection level, and the combined mass of benzene, toluene, ethylbenzene, and total xylene was detected above the detection level in 31 of the 71 samplers that were analyzed. Other volatile organic compounds detected above their respective method detection levels were naphthalene, 2-methyl-naphthalene, tridecane, 1,2,4-trimethylbenzene, and perchloroethene. Subsequent to the soil-gas survey, four areas determined to have elevated contaminant mass were selected and sampled for explosives and chemical agents. No detections of explosives or chemical agents above their

  13. Air-Based Remediation Workshop - Section 2 Soil Vapor Extraction

    EPA Science Inventory

    Pursuant to the EPA-AIT Implementing Arrangement 7 for Technical Environmental Collaboration, Activity 11 "Remediation of Contaminated Sties," the USEPA Office of International Affairs Organized a Forced Air Remediation Workshop in Taipei to deliver expert training to the Environ...

  14. [Vertical Migration Characteristics of Organochlorine Pesticides in Overlying Soil in Karst Terranes and Its Impact on Groundwater].

    PubMed

    Sun, Yu-chuan; Wang, Yong-qi; Liang, Zuo-bing; Yuan, Dao-xian

    2015-05-01

    Five soil profiles and four typical epikarst springs were selected in Nanchuan District, Chongqing Municipality as objects of the study on vertical migration of organochlorine pesticides (OCPs) in the soils and its impact on groundwater. OCPs in soil and epikarst spring water samples were quantitatively analyzed by gas chromatography. The results showed that HCHs and DDTs were detected in all the 5 soil profiles, varying in the range of 0.77-18.3 and 0.34-226 ng · g(-1), and averaging 5.16 and 16 ng · g(-1) in concentration, respectively. The highest concentrations of HCHs and DDTs were found in the subsoil (10-40 cm) in most sampling sites. The detection ratios of HCHs and DDTs in four springs were 100%. The concentrations of HCHs and DDTs fluctuated greatly in epikarst spring water during the one-year observation, and the concentration ranged from 2.09 to 60.1 and from N. D. to 79.8 ng · L(-1), with a mean value of 12 and 9.16 ng · L(-1), respectively. The concentrations of HCHs and DDTs in Hougou, Baishuwan and Lanhuagou spring in rainy season were all. higher than those in dry season in these three epikarst springs. There were no good corresponding relationship between HCHs and DDTs contents in spring water and those in corresponding spring catchment soil. TOC, soil water content, clay content and pH all inhibited the vertical migration of OCPs in Hougou spring catchment, which led to the lowest content of OCPs in spring water, although the OCPs content in Hougou spring catchment soils was the highest in the four spring catchments. However, the four factors didn't inhibit the vertical migration of OCPs in Shuifang spring catchment, which led to higher OCPs content in spring water, although the OCPs content in spring catchment soils was the lowest in the four spring catchments.

  15. Threshold velocities for input of soil particles into the air by desert soils

    SciTech Connect

    Gillette, D.A.; Adams, J.; Endo, A.; Smith, D.; Kihl, R.

    1980-10-20

    Desert soils mostly from the Mojave Desert were tested for threshold friction velocity (the friction velocity above which soil erosion takes place) with an open-bottomed portable wind tunnel. Several geomorphological settings were chosen to be representative of much of the surface of the Mojave Desert, for example, playas, alluvial fans, and aeolian features. Variables which increase threshold velocity are decreasing proportion of sand, increasing size of dry aggregates of the soil, and increasing fraction of the soil mass larger than 1 mm. Threshold velocity increases with different types of soil surfaces in the following order: disturbed soils (except disturbed heavy clay soils), sand dunes, alluvial and aeolian sand deposits, disturbed playa soils, skirts of playas, playa centers, and desert pavement (alluvial deposits). 21 references, 5 figures, 6 tables.

  16. Hot air injection for removal of dense, non-aqueous-phase liquid contaminants from low-permeability soils

    SciTech Connect

    Payne, F.C.

    1996-08-01

    The performance of soil vapor extraction systems for the recovery of volatile and semi-volatile organic compounds is potentially enhanced by the injection of heated air to increase soil temperatures. The soil temperature increase is expected to improve soil vapor extraction (SVE) performance by increasing target compound vapor pressures and by increasing soil permeability through drying. The vapor pressure increase due to temperature rise relieves the vapor pressure limit on the feasibility of soil vapor extraction. However, the system still requires an air flow through the soil system to deliver heat and to recover mobilized contaminants. Although the soil permeability can be increased through drying, very low permeability soils and low permeability soils adjacent to high permeability air flow pathways will be treated slowly, if at all. AR thermal enhancement methods face this limitation. Heated air injection offers advantages relative to other thermal techniques, including low capital and operation costs. Heated air injection is at a disadvantage relative to other thermal techniques due to the low heat capacity of air. To be effective, heated air injection requires that higher air flows be established than for steam injection or radio frequency heating. Heated air injection is not economically feasible for the stratified soil system developed as a standard test for this document. This is due to the inability to restrict heated air flow to the clay stratum when a low-resistance air flow pathway is available in the adjoining sand. However, the technology should be especially attractive, both technically and economically, for low-volatile contaminant recovery from relatively homogeneous soil formations. 16 refs., 2 tabs.

  17. Soil concentrations, occurrence, sources and estimation of air-soil exchange of polychlorinated biphenyls in Indian cities.

    PubMed

    Chakraborty, Paromita; Zhang, Gan; Li, Jun; Selvaraj, Sakthivel; Breivik, Knut; Jones, Kevin C

    2016-08-15

    Past studies have shown potentially increasing levels of polychlorinated biphenyls (PCBs) in the Indian environment. This is the first attempt to investigate the occurrence of PCBs in surface soil and estimate diffusive air-soil exchange, both on a regional scale as well as at local level within the metropolitan environment of India. From the north, New Delhi and Agra, east, Kolkata, west, Mumbai and Goa and Chennai and Bangalore in the southern India were selected for this study. 33 PCB congeners were quantified in surface soil and possible sources were derived using positive matrix factorization model. Net flux directions of PCBs were estimated in seven major metropolitan cities of India along urban-suburban-rural transects. Mean Σ33PCBs concentration in soil (12ng/g dry weight) was nearly twice the concentration found in global background soil, but in line with findings from Pakistan and urban sites of China. Higher abundance of the heavier congeners (6CB-8CB) was prevalent mostly in the urban centers. Cities like Chennai, Mumbai and Kolkata with evidence of ongoing PCB sources did not show significant correlation with soil organic carbon (SOC). This study provides evidence that soil is acting as sink for heavy weight PCB congeners and source for lighter congeners. Atmospheric transport is presumably a controlling factor for occurrence of PCBs in less polluted sites of India.

  18. Air stripping. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1995-02-01

    The bibliography contains citations concerning the application of air stripping techniques to water treatment, including groundwater decontamination and wastewater purification. The advantages and disadvantages of air stripping over other water treatment processes are discussed. Cleanup of the organic emissions generated by air stripping is also considered. The primary applications of air stripping are in groundwater and soil cleanup. (Contains a minimum of 89 citations and includes a subject term index and title list.)

  19. Air stripping. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-02-01

    The bibliography contains citations concerning the application of air stripping techniques to water treatment, including groundwater decontamination and wastewater purification. The advantages and disadvantages of air stripping over other water treatment processes are discussed. Cleanup of the organic emissions generated by air stripping is also considered. The primary applications of air stripping are in groundwater and soil cleanup. (Contains a minimum of 83 citations and includes a subject term index and title list.)

  20. Air stripping. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1995-12-01

    The bibliography contains citations concerning the application of air stripping techniques to water treatment, including groundwater decontamination and wastewater purification. The advantages and disadvantages of air stripping over other water treatment processes are discussed. Cleanup of the organic emissions generated by air stripping is also considered. The primary applications of air stripping are in groundwater and soil cleanup. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  1. Air stripping. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1997-03-01

    The bibliography contains citations concerning the application of air stripping techniques to water treatment, including groundwater decontamination and wastewater purification. The advantages and disadvantages of air stripping over other water treatment processes are discussed. Cleanup of the organic emissions generated by air stripping is also considered. The primary applications of air stripping are in groundwater and soil cleanup. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  2. Health risk estimates for groundwater and soil contamination in the Slovak Republic: a convenient tool for identification and mapping of risk areas.

    PubMed

    Fajčíková, K; Cvečková, V; Stewart, A; Rapant, S

    2014-10-01

    We undertook a quantitative estimation of health risks to residents living in the Slovak Republic and exposed to contaminated groundwater (ingestion by adult population) and/or soils (ingestion by adult and child population). Potential risk areas were mapped to give a visual presentation at basic administrative units of the country (municipalities, districts, regions) for easy discussion with policy and decision-makers. The health risk estimates were calculated by US EPA methods, applying threshold values for chronic risk and non-threshold values for cancer risk. The potential health risk was evaluated for As, Ba, Cd, Cu, F, Hg, Mn, NO3 (-), Pb, Sb, Se and Zn for groundwater and As, B, Ba, Be, Cd, Cu, F, Hg, Mn, Mo, Ni, Pb, Sb, Se and Zn for soils. An increased health risk was identified mainly in historical mining areas highly contaminated by geogenic-anthropogenic sources (ore deposit occurrence, mining, metallurgy). Arsenic and antimony were the most significant elements in relation to health risks from groundwater and soil contamination in the Slovak Republic contributing a significant part of total chronic risk levels. Health risk estimation for soil contamination has highlighted the significance of exposure through soil ingestion in children. Increased cancer risks from groundwater and soil contamination by arsenic were noted in several municipalities and districts throughout the country in areas with significantly high arsenic levels in the environment. This approach to health risk estimations and visualization represents a fast, clear and convenient tool for delineation of risk areas at national and local levels.

  3. Estimation of soil air permeability components at a laboratory-scale pilot.

    PubMed

    Boudouch, Otmane; Esrael, Daoud; Kacem, Mariem; Benadda, Belkacem

    2012-01-01

    Soil air permeability is a key parameter in the design of soil vapour extraction. The purpose of this study is to verify the applicability of different analytical solutions, developed to determine soil characteristics in field conditions, to estimate soil air permeability in a small-scale pilot, since field testing may be expensive. A laboratory tridirectional pilot and a unidirectional column were designed in order to achieve the objectives of this work. Use of a steady-state unconfined analytical solution was found to be an appropriate method to determine soil air permeability components for the pilot conditions. Using pressure data collected under open, steady-state conditions, the average values of radial and vertical permeability were found to be, respectively, 9.97 x 10(-7) and 8.74 x 10(-7) cm2. The use of semi-confined analytical solutions may not be suitable to estimate soil parameters since a significant difference was observed between simulated and observed vacuums. Air permeability was underestimated when transient solutions were used, in comparison with methods based on steady-state solutions. The air radial and vertical permeability was found to be, respectively, 7.06 x 10(-7) and 4.93 x 10(-7) cm2, in the open scenario, and 2.30 x 10(-7) and 1.51 x 10(-7) cm2 in the semi-confined scenario. However, a good estimate of soil porosity was achieved using the two transient methods. The average values were predicted to be 0.482, in the open scenario, and 0.451 in the semi-confined scenario, which was in good agreement with the real value.

  4. Overview of Green and Sustainable Remediation for Soil and Groundwater Remediation - 12545

    SciTech Connect

    Simpkin, Thomas J.; Favara, Paul

    2012-07-01

    Making remediation efforts more 'sustainable' or 'green' is a topic of great interest in the remediation community. It has been spurred on by Executive Orders from the White House, as well as Department of Energy (DOE) sustainability plans. In private industry, it is motivated by corporate sustainability goals and corporate social responsibility. It has spawned new organizations, areas of discussion, tools and practices, and guidance documents around sustainable remediation or green remediation. Green remediation can be thought of as a subset of sustainable remediation and is mostly focused on reducing the environmental footprint of cleanup efforts. Sustainable remediation includes both social and economic considerations, in addition to environmental. Application of both green and sustainable remediation (GSR) may involve two primary activities. The first is to develop technologies and alternatives that are greener or more sustainable. This can also include making existing remediation approaches greener or more sustainable. The second is to include GSR criteria in the evaluation of remediation alternatives and strategies. In other words, to include these GSR criteria in the evaluation of alternatives in a feasibility study. In some cases, regulatory frameworks allow the flexibility to include GSR criteria into the evaluation process (e.g., state cleanup programs). In other cases, regulations allow less flexibility to include the evaluation of GSR criteria (e.g., Comprehensive Environmental Response Compensation, and Liability Act (CERCLA)). New regulatory guidance and tools will be required to include these criteria in typical feasibility studies. GSR provides a number of challenges for remediation professionals performing soil and groundwater remediation projects. Probably the most significant is just trying to stay on top of the ever changing landscape of products, tools, and guidance documents coming out of various groups, the US EPA, and states. However, this

  5. Ground-water hydrology and simulation of ground-water flow at Operable Unit 3 and surrounding region, U.S. Naval Air Station, Jacksonville, Florida

    USGS Publications Warehouse

    Davis, J.H.

    1998-01-01

    The Naval Air Station, Jacksonville (herein referred to as the Station), occupies 3,800 acres adjacent to the St. Johns River in Duval County, Florida. Operable Unit 3 (OU3) occupies 134 acres on the eastern side of the Station and has been used for industrial and commercial purposes since World War II. Ground water contaminated by chlorinated organic compounds has been detected in the surficial aquifer at OU3. The U.S. Navy and U.S. Geological Survey (USGS) conducted a cooperative hydrologic study to evaluate the potential for ground water discharge to the neighboring St. Johns River. A ground-water flow model, previously developed for the area, was recalibrated for use in this study. At the Station, the surficial aquifer is exposed at land surface and forms the uppermost permeable unit. The aquifer ranges in thickness from 30 to 100 feet and consists of unconsolidated silty sands interbedded with local beds of clay. The low-permeability clays of the Hawthorn Group form the base of the aquifer. The USGS previously conducted a ground-water investigation at the Station that included the development and calibration of a 1-layer regional ground-water flow model. For this investigation, the regional model was recalibrated using additional data collected after the original calibration. The recalibrated model was then used to establish the boundaries for a smaller subregional model roughly centered on OU3. Within the subregional model, the surficial aquifer is composed of distinct upper and intermediate layers. The upper layer extends from land surface to a depth of approximately 15 feet below sea level; the intermediate layer extends from the upper layer down to the top of the Hawthorn Group. In the northern and central parts of OU3, the upper and intermediate layers are separated by a low-permeability clay layer. Horizontal hydraulic conductivities in the upper layer, determined from aquifer tests, range from 0.19 to 3.8 feet per day. The horizontal hydraulic

  6. Utilization of air pollution control residues for the stabilization/solidification of trace element contaminated soil.

    PubMed

    Travar, I; Kihl, A; Kumpiene, J

    2015-12-01

    The aim of this study was to evaluate the stabilization/solidification (S/S) of trace element-contaminated soil using air pollution control residues (APCRs) prior to disposal in landfill sites. Two soil samples (with low and moderate concentrations of organic matter) were stabilized using three APCRs that originated from the incineration of municipal solid waste, bio-fuels and a mixture of coal and crushed olive kernels. Two APCR/soil mixtures were tested: 30% APCR/70% soil and 50% APCR/50% soil. A batch leaching test was used to study immobilization of As and co-occurring metals Cr, Cu, Pb and Zn. Solidification was evaluated by measuring the unconfined compression strength (UCS). Leaching of As was reduced by 39-93% in APCR/soil mixtures and decreased with increased amounts of added APCR. Immobilization of As positively correlated with the amount of Ca in the APCR and negatively with the amount of soil organic matter. According to geochemical modelling, the precipitation of calcium arsenate (Ca3(AsO4)2/4H2O) and incorporation of As in ettringite (Ca6Al2(SO4)3(OH)12 · 26H2O) in soil/APCR mixtures might explain the reduced leaching of As. A negative effect of the treatment was an increased leaching of Cu, Cr and dissolved organic carbon. Solidification of APCR/soil was considerably weakened by soil organic matter.

  7. Task summary for cone penetrating testing sounding and soil and groundwater sampling Salmon Site, Lamar County, Mississippi

    SciTech Connect

    Not Available

    1994-10-01

    The Salmon Site (SS), located in Mississippi, was the site of two nuclear and two gas explosion testes conducted deep underground in the Tatum Salt Dome between 1964 and 1970. As a consequence radionuclides generated during the testing were released into the salt dome. During reentry drilling and other site activities, incidental liquid and solid wastes that contained radioactivity were generated, resulting in some soil, ground water and equipment contamination. US DOE is conducting a series of investigations as a part of the Remedial Investigation and Feasibility Study (under CERCLA) This report summarizes the cone penetrometer testing (CPT) and sampling program conducted in fall 1993, providing a description of the activities and a discussion of the results. The objectives of the CPT program were to determine subsurface conditions and stratification; determine the depth to the potentiometric surface; obtain soil samples from predetermined depths; obtain groundwater samples at predetermined depths.

  8. Dynamics of air gap formation around roots with changing soil water content.

    NASA Astrophysics Data System (ADS)

    Vetterlein, D.; Carminati, A.; Weller, U.; Oswald, S.; Vogel, H.-J.

    2009-04-01

    Most models regarding uptake of water and nutrients from soil assume intimate contact between roots and soil. However, it is known for a long time that roots may shrink under drought conditions. Due to the opaque nature of soil this process could not be observed in situ until recently. Combining tomography of the entire sample (field of view of 16 x 16 cm, pixel side 0.32 mm) with local tomography of the soil region around roots (field of view of 5 x 5 cm, pixel side 0.09 mm), the high spatial resolution required to image root shrinkage and formation of air-filled gaps around roots could be achieved. Applying this technique and combining it with microtensiometer measurements, measurements of plant gas exchange and microscopic assessment of root anatomy, a more detailed study was conducted to elucidate at which soil matric potential roots start to shrink in a sandy soil and which are the consequences for plant water relations. For Lupinus albus grown in a sandy soil tomography of the entire root system and of the interface between taproot and soil was conducted from day 11 to day 31 covering two drying cycles. Soil matric potential decreased from -36 hPa at day 11 after planting to -72, -251, -429 hPa, on day 17, 19, 20 after planting. On day 20 an air gap started to occur around the tap root and extended further on day 21 with matric potential below -429 hPa (equivalent to 5 v/v % soil moisture). From day 11 to day 21 stomatal conductivity decreased from 467 to 84 mmol m-2 s-1, likewise transpiration rate decreased and plants showed strong wilting symptoms on day 21. Plants were watered by capillary rise on day 21 and recovered completely within a day with stomatal conductivity increasing to 647 mmol m-2 s-1. During a second drying cycle, which was shorter as plants continuously increased in size, air gap formed again at the same matric potential. Plant stomatal conductance and transpiration decreased in a similar fashion with decreasing matric potential and

  9. Air temperature evolution during dry spells and its relation to prevailing soil moisture regimes

    NASA Astrophysics Data System (ADS)

    Schwingshackl, Clemens; Hirschi, Martin; Seneviratne, Sonia I.

    2015-04-01

    The complex interplay between land and atmosphere makes accurate climate predictions very challenging, in particular with respect to extreme events. More detailed investigations of the underlying dynamics, such as the identification of the drivers regulating the energy exchange at the land surface and the quantification of fluxes between soil and atmosphere over different land types, are thus necessary. The recently started DROUGHT-HEAT project (funded by the European Research Council) aims to provide better understanding of the processes governing the land-atmosphere exchange. In the first phase of the project, different datasets and methods are used to investigate major drivers of land-atmosphere dynamics leading to droughts and heatwaves. In the second phase, these findings will be used for reducing uncertainties and biases in earth system models. Finally, the third part of the project will focus on the application of the previous findings and use them for the attribution of extreme events to land processes and possible mitigation through land geoengineering. One of the major questions in land-atmosphere exchange is the relationship between air temperature and soil moisture. Different studies show that especially during dry spells soil moisture has a strong impact on air temperature and the amplification of hot extremes. Whereas in dry and wet soil moisture regimes variations in latent heat flux during rain-free periods are expected to be small, this is not the case in transitional soil moisture regimes: Due to decreasing soil moisture content latent heat flux reduces with time, which causes in turn an increase in sensible heat flux and, subsequently, higher air temperatures. The investigation of air temperature evolution during dry spells can thus help to detect different soil moisture regimes and to provide insights on the effect of different soil moisture levels on air temperature. Here we assess the underlying relationships using different observational and

  10. Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Seuntjens, P.; Joris, I.; Boënne, W.; Van Hoey, S.; Campling, P.; Cornelis, W. M.

    2016-01-01

    Monitoring and modelling tools may improve irrigation strategies in precision agriculture. We used non-invasive soil moisture monitoring, a crop growth and a soil hydrological model to predict soil water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. The sensitivity of the soil hydrological model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed after integrating models. Free drainage and incremental constant head conditions were implemented in a lower boundary sensitivity analysis. A time-dependent sensitivity analysis of the hydraulic parameters showed that changes in soil water content are mainly affected by the soil saturated hydraulic conductivity Ks and the Mualem-van Genuchten retention curve shape parameters n and α. Results further showed that different parameter optimization strategies (two-, three-, four- or six-parameter optimizations) did not affect the calculated water stress and water content as significantly as does the bottom boundary. In this case, a two-parameter scenario, where Ks was optimized for each layer under the condition of a constant groundwater depth at 135-140 cm, performed best. A larger yield reduction, and a larger number and longer duration of stress conditions occurred in the free drainage condition as compared to constant boundary conditions. Numerical results showed that optimal irrigation scheduling using the aforementioned water stress calculations can save up to 12-22 % irrigation water as compared to the current irrigation regime. This resulted in a yield increase of 4.5-6.5 %, simulated by the crop growth model.

  11. Air stripping of volatile organic compounds from groundwater: An evaluation of a centrifugal vapor-liquid contractor

    SciTech Connect

    Singh, S.P.

    1989-01-01

    The performance of a centrifugal vapor-liquid contactor equipped with high specific surface area packing (>2,000 m{sup 2}/m{sup 3}) was evaluated for air stripping of jet fuel components from groundwater. Hydraulic test data indicated that the Sherwood flooding correlation which has been proposed for use in designing centrifugal vapor-liquid contactors overestimates the rotational speeds at which flooding occurs. For the mass transfer performance, a concept of area of a transfer unit (ATU) was introduced to account for the change in fluid loading with radius of the packing torus. The ATU was found to be a strong function of the specific surface area of the packing and to a lesser extent a function of rotor speed and liquid flow rate. A correlation based on the specific surface area of the packing is proposed for predicting the ATU. A simple empirical model is also proposed for determining the power consumed in turning the packing torus at various operating conditions. Previous claims in the literature that centrifugal vapor-liquid contactor is resistant to fouling because of high shear force were found not to be valid for groundwater with high iron content.

  12. Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) in soils and groundwater of a U.S. metropolitan area: migration and implications for human exposure.

    PubMed

    Xiao, Feng; Simcik, Matt F; Halbach, Thomas R; Gulliver, John S

    2015-04-01

    Perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are emerging anthropogenic compounds that have recently become the target of global concern due to their ubiquitous presence in the environment, persistence, and bioaccumulative properties. This study was carried out to investigate the migration of PFOS and PFOA in soils and groundwater in a U.S. metropolitan area. We observed elevated levels in surface soils (median: 12.2 ng PFOS/g dw and 8.0 ng PFOA/g dw), which were much higher than the soil-screening levels for groundwater protection developed in this study. The measured levels in subsurface soils show a general increase with depth, suggesting a downward movement toward the groundwater table and a potential risk of aquifer contamination. Furthermore, concentrations of PFOS and PFOA in monitoring wells in the source zone varied insignificantly over 5 years (2009-2013), suggesting limited or no change in either the source or the magnitude of the source. The analysis also shows that natural processes of dispersion and dilution can significantly attenuate the groundwater contamination; the adsorption on aquifer solids, on the other hand, appears to have limited effects on the transport of PFOS and PFOA in the aquifer. The probabilistic exposure assessment indicates that ingestion of contaminated groundwater constitutes a much more important exposure route than ingestion of contaminated soil. Overall, the results suggest that (i) the transport of PFOS and PFOA is retarded in the vadose zone, but not in the aquifer; (ii) the groundwater contamination of PFOS and PFOA often follows their release to surface soils by years, if not decades; and (iii) the aquifer can be a major source of exposure for communities living near point sources.

  13. Model for in situ air stripping of contaminated soils: Effects of hydrocarbon adsorption

    SciTech Connect

    Mehrotra, A.K.; Karan, K.; Chakma, A.

    1996-01-01

    Soil contamination due to organic compounds is a widespread problem. The contaminants enter the soil subsurface by a number of routes, such as the disposal of wastes in landfills, spills during transportation of chemicals, plant operation, and leakage from underground storage. Air stripping as a means of soil remediation has gained popularity in recent years. In this in situ process, clean air is injected into the contaminated soil zone to volatilize and strip the contaminants, which are then removed by the carrier gas. The process has been found to be effective especially for treating the vadose zone of the soil contaminated with volatile and semivolatile organics. Nitrogen adsorption/desorption experiments in this study were performed on a soil sample to establish its desorption characteristics. A field-scale model for the air stripping process has been developed to simulate the removal of semivolatile hydrocarbons. The numerical results show that the interphase contaminant transport from the sorbed to the vapor phase plays a dominant role in influencing the process effectiveness.

  14. Global modeling of the fate of nitrogen from point and nonpoint sources in soils, groundwater, and surface water

    NASA Astrophysics Data System (ADS)

    van Drecht, G.; Bouwman, A. F.; Knoop, J. M.; Beusen, A. H. W.; Meinardi, C. R.

    2003-12-01

    We present a global model that describes the fate of nitrogen (N) from point and nonpoint sources in the hydrological system up to the river mouths at the 0.5° by 0.5° spatial and annual temporal resolution. Estimates for point sources are based on population densities, per capita human N emissions, and data on sanitation coverage and wastewater treatment. For nonpoint sources, we use spatial information on land use, climate, hydrology, geology, and soils, combined with data on N inputs (fertilizers and animal manure, biological N fixation, and atmospheric deposition), and outputs (N removal in harvested agricultural products, ammonia emissions). Denitrification in the root zone and nitrate leaching to groundwater are calculated with a model that combines the effect of temperature, crop type, soil properties, and hydrological conditions. The nitrate concentration of the outflow for shallow and deep groundwater layers is based on historical inputs of fertilizer N and the effects of residence time and denitrification. In-stream N retention is based on a global estimate of 30% of the N discharged to surface water. Calculated and reported total N concentrations of discharge near the river outlet agree fairly well. However, our model systematically overestimates total N concentrations for river basins with mean annual temperature >0°C.

  15. Comparative study of multimedia models applied to the risk assessment of soil and groundwater contamination sites in Taiwan.

    PubMed

    Fan, Chihhao; Chen, Yen-chuan; Ma, Hwong-wen; Wang, Gen-shuh

    2010-10-15

    The purpose of this study was to explore the applicability of two popular multimedia risk assessment models to three different soil and groundwater contamination sites in Taiwan. The Multimedia Environmental Pollutant Assessment System (MEPAS) and the Multimedia Contaminant Fate, Transport, and Exposure Model (MMSOILS) were selected because of their wide application and use. Three soil and groundwater contamination sites in Taiwan were employed as illustrative examples in the comparison of these two risk assessment models. Three exposure pathways were investigated, categorized as oral ingestion, dermal absorption, and inhalation. The results show that MEPAS and MMSOILS calculated similar cancer risks and hazard quotients in general, but were different by two orders of magnitude in cancer risk estimates for sites contaminated by volatile organic compounds (VOC). Using MMSOILS may not be appropriate for risk assessment of such sites, as it does not account for indoor inhalation as a potential exposure pathway in its risk calculations. Water ingestion, dermal absorption when showering and indoor inhalation were the three most predominant contributing exposure pathways for risk development among sites contaminated by VOCs. On the other hand, crop and meat ingestion were more important exposure pathways in the context of sites with non-VOC pollutants, because these hydrophobic contaminants may be bio-accumulative in plants and animals, and consequently enter the human body via food chains.

  16. Multivariate curve resolution of organic pollution patterns in the Ebro River surface water-groundwater-sediment-soil system.

    PubMed

    Terrado, Marta; Barceló, Damià; Tauler, Romà

    2010-01-01

    Multivariate curve resolution alternating least squares (MCR-ALS) is shown to be a powerful chemometric method for the analysis of environmental monitoring data sets. It allows for the investigation, resolution, identification, and description of pollution patterns distributed over a particular geographical area, time and environmental compartment. An integrated interpretation of the main features characterizing pollution patterns of organic contaminants affecting the Ebro River basin (Catalonia, NE Spain) is attempted using the results obtained by MCR-ALS analysis of surface water, groundwater, sediment and soil data sets obtained in a 3-year extensive monitoring study. Agricultural practices were identified as the main source of surface and groundwater diffuse pollution, while sediments and soils appeared mostly polluted by a contamination pattern mainly loaded by polycyclic aromatic hydrocarbons (PAHs) of possible pyrolitic origin. Additionally, a third pollution pattern related to past and ongoing industrial activities was detected to be principally stored in the sediment compartment. Geographical and temporal distributions of these pollution sources are given.

  17. Long-term (1930-2010) trends in groundwater levels in Texas: influences of soils, landcover and water use.

    PubMed

    Chaudhuri, Sriroop; Ale, Srinivasulu

    2014-08-15

    Rapid groundwater depletion has raised grave concerns about sustainable development in many parts of Texas, as well as in other parts of the world. Previous hydrologic investigations on groundwater levels in Texas were conducted mostly on aquifer-specific basis, and hence lacked state-wide panoramic view. The aim of this study was to present a qualitative overview of long-term (1930-2010) trends in groundwater levels in Texas and identify spatial patterns by applying different statistical (boxplots, correlation-regression, hierarchical cluster analysis) and geospatial techniques (Moran's I, Local Indicators of Spatial Association) on 136,930 groundwater level observations from Texas Water Development Board's database. State-wide decadal median water-levels declined from about 14 m from land surface in the 1930s to about 36 m in the 2000s. Number of counties with deeper median water-levels (water-level depth>100 m) increased from 2 to 13 between 1930s and 2000s, accompanied by a decrease in number of counties having shallower median water-levels (water-level depth<25 m) from 134 to 113. Water-level declines across Texas, however, mostly followed logarithmic trends marked by leveling-off phenomena in recent times. Assessment of water-levels by Groundwater Management Areas (GMA), management units created to address groundwater depletion issues, indicated hotspots of deep water-levels in Texas Panhandle and GMA 8 since the 1960s. Contrasting patterns in water use, landcover, geology and soil properties distinguished Texas Panhandle from GMA 8. Irrigated agriculture is the major cause of depletion in the Texas Panhandle as compared to increasing urbanization in GMA 8. Overall our study indicated that use of robust spatial and statistical methods can reveal important details about the trends in water-level changes and shed lights on the associated factors. Due to very generic nature, techniques used in this study can also be applied to other areas with similar eco

  18. Long-term (1930-2010) trends in groundwater levels in Texas: influences of soils, landcover and water use.

    PubMed

    Chaudhuri, Sriroop; Ale, Srinivasulu

    2014-08-15

    Rapid groundwater depletion has raised grave concerns about sustainable development in many parts of Texas, as well as in other parts of the world. Previous hydrologic investigations on groundwater levels in Texas were conducted mostly on aquifer-specific basis, and hence lacked state-wide panoramic view. The aim of this study was to present a qualitative overview of long-term (1930-2010) trends in groundwater levels in Texas and identify spatial patterns by applying different statistical (boxplots, correlation-regression, hierarchical cluster analysis) and geospatial techniques (Moran's I, Local Indicators of Spatial Association) on 136,930 groundwater level observations from Texas Water Development Board's database. State-wide decadal median water-levels declined from about 14 m from land surface in the 1930s to about 36 m in the 2000s. Number of counties with deeper median water-levels (water-level depth>100 m) increased from 2 to 13 between 1930s and 2000s, accompanied by a decrease in number of counties having shallower median water-levels (water-level depth<25 m) from 134 to 113. Water-level declines across Texas, however, mostly followed logarithmic trends marked by leveling-off phenomena in recent times. Assessment of water-levels by Groundwater Management Areas (GMA), management units created to address groundwater depletion issues, indicated hotspots of deep water-levels in Texas Panhandle and GMA 8 since the 1960s. Contrasting patterns in water use, landcover, geology and soil properties distinguished Texas Panhandle from GMA 8. Irrigated agriculture is the major cause of depletion in the Texas Panhandle as compared to increasing urbanization in GMA 8. Overall our study indicated that use of robust spatial and statistical methods can reveal important details about the trends in water-level changes and shed lights on the associated factors. Due to very generic nature, techniques used in this study can also be applied to other areas with similar eco

  19. Identifying groundwater recharge connections in the Moscow (USA) sub-basin using isotopic tracers and a soil moisture routing model

    NASA Astrophysics Data System (ADS)

    Candel, Jasper; Brooks, Erin; Sánchez-Murillo, Ricardo; Grader, George; Dijksma, Roel

    2016-06-01

    Globally, aquifers are suffering from large abstractions resulting in groundwater level declines. These declines can be caused by excessive abstraction for drinking water, irrigation purposes or industrial use. Basaltic aquifers also face these conflicts. A large flood basalt area (1.1 × 105 km2) can be found in the Northwest of the USA. This Columbia River Basalt Group (CRBG) consists of a thick series of basalt flows of Miocene age. The two major hydrogeological units (Wanapum and Grand Ronde formations) are widely used for water abstraction. The mean decline over recent decades has been 0.6 m year-1. At present day, abstraction wells are drying up, and base flow of rivers is reduced. At the eastern part of CRBG, the Moscow sub-basin on the Idaho/Washington State border can be found. Although a thick poorly permeable clay layer exists on top of the basalt aquifer, groundwater level dynamics suggest that groundwater recharge occurs at certain locations. A set of wells and springs has been monitored bi-weekly for 9 months for δ18O and δ2H. Large isotopic fluctuations and d-excess values close to the meteoric water line in some wells are indicating that recharge occurs at the granite/basalt interface through lateral flow paths in and below the clay. A soil moisture routing (SMR) model showed that most recharge occurs on the granitic mountains. The basaltic aquifer receives recharge from these sedimentary zones around the granite/basalt interface. The identification of these types of areas is of major importance for future managed-aquifer recharge solutions to solve problems of groundwater depletion.

  20. BOREAS RSS-17 Stem, Soil, and Air Temperature Data

    NASA Technical Reports Server (NTRS)

    Zimmerman, Reiner; McDonald, Kyle C.; Way, JoBea; Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS RSS-17 team collected several data sets in support of its research in monitoring and analyzing environmental and phenological states using radar data. This data set consists of tree bole and soil temperature measurements from various BOREAS flux tower sites. Temperatures were measured with thermistors implanted in the hydroconductive tissue of the trunks of several trees at each site and at various depths in the soil. Data were stored on a data logger at intervals of either 1 or 2 hours. The majority of the data were acquired between early 1994 and early 1995. The primary product of this data set is the diurnal stem temperature measurements acquired for selected trees at five BOREAS tower sites. The data are provided in tabular ASCII format. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  1. Method for in situ or ex situ bioremediation of hexavalent chromium contaminated soils and/or groundwater

    DOEpatents

    Turick, C.E.; Apel, W.W.

    1997-10-28

    A method of reducing the concentration of Cr(VI) in a liquid aqueous residue comprises the steps of providing anaerobic Cr(VI) reducing bacteria, mixing the liquid aqueous residue with a nutrient medium to form a mixture, and contacting the mixture with the anaerobic Cr(VI) reducing bacteria such that Cr(VI) is reduced to Cr(III). The anaerobic Cr(VI) reducing bacteria appear to be ubiquitous in soil and can be selected by collecting a soil sample, diluting the soil sample with a sterile diluent to form a diluted sample, mixing the diluted sample with an effective amount of a nutrient medium and an effective amount of Cr(VI) to form a mixture, and incubating the mixture in the substantial absence of oxygen such that growth of Cr(VI) sensitive microorganisms is inhibited and growth of the anaerobic Cr(VI) reducing bacteria is stimulated. A method of in situ bioremediation of Cr(VI) contaminated soil and/or groundwater is also disclosed. 10 figs.

  2. Method for in situ or ex situ bioremediation of hexavalent chromium contaminated soils and/or groundwater

    DOEpatents

    Turick, Charles E.; Apel, William W.

    1997-10-28

    A method of reducing the concentration of Cr(VI) in a liquid aqueous residue comprises the steps of providing anaerobic Cr(VI) reducing bacteria, mixing the liquid aqueous residue with a nutrient medium to form a mixture, and contacting the mixture with the anaerobic Cr(VI) reducing bacteria such that Cr(VI) is reduced to Cr(III). The anaerobic Cr(VI) reducing bacteria appear to be ubiquitous in soil and can be selected by collecting a soil sample, diluting the soil sample with a sterile diluent to form a diluted sample, mixing the diluted sample with an effective amount of a nutrient medium and an effective amount of Cr(VI) to form a mixture, and incubating the mixture in the substantial absence of oxygen such that growth of Cr(VI) sensitive microorganisms is inhibited and growth of the anaerobic Cr(VI) reducing bacteria is stimulated. A method of in situ bioremediation of Cr(VI) contaminated soil and/or groundwater is also disclosed.

  3. A comparison of the soil migration and plant uptake of radioactive chlorine and iodine from contaminated groundwater.

    PubMed

    Ashworth, D J; Shaw, G

    2006-01-01

    A 6-month soil column experiment was conducted to compare the upward migration and plant uptake of radiochlorine and radioiodine from shallow, near-surface contaminated water tables. Both fixed and fluctuating water tables were studied. After 6 months, (36)Cl activity concentrations were relatively uniform throughout the soil profile apart from an accumulation at the soil surface, which was especially marked under a fluctuating water table scenario. In contrast, (125)I (a surrogate for (129)I) tended to accumulate at the boundary between the anoxic conditions at the base of the column and the oxic conditions above, due to its redox-dependent sorption behaviour. The uptake of (36)Cl by perennial ryegrass was much greater than that of (125)I due to its greater migration into the rooting zone and its ready availability in soil solution. In the context of radioactive waste disposal, where these radionuclides may potentially be released into groundwater, (36)Cl would be expected to present a greater potential for contamination of the biosphere than (129)I.

  4. Extreme environments in the critical zone: Linking acidification hazard of acid sulfate soils in mound spring discharge zones to groundwater evolution and mantle degassing.

    PubMed

    Shand, Paul; Gotch, Travis; Love, Andrew; Raven, Mark; Priestley, Stacey; Grocke, Sonia

    2016-10-15

    A decrease in flow from the iconic travertine mound springs of the Great Artesian Basin in South Australia has led to the oxidation of hypersulfidic soils and extreme soil acidification, impacting their unique groundwater dependent ecosystems. The build-up of pyrite in these systems occurred over millennia by the discharge of deep artesian sulfate-containing groundwaters through organic-rich subaqueous soils. Rare iron and aluminium hydroxysulfate minerals form thick efflorescences due to high evaporation rates in this arid zone environment, and the oxidised soils pose a significant risk to local aquatic and terrestrial ecosystems. The distribution of extreme acidification hazard is controlled by regional variations in the hydrochemistry of groundwater. Geochemical processes fractionate acidity and alkalinity into separate parts of the discharge zone allowing potentially extreme environments to form locally. Differences in groundwater chemistry in the aquifer along flow pathways towards the spring discharge zone are related to a range of processes including mineral dissolution and redox reactions, which in turn are strongly influenced by degassing of the mantle along deep crustal fractures. There is thus a connection between shallow critical zone ecosystems and deep crustal/mantle processes which ultimately control the formation of hypersulfidic soils and the potential for extreme geochemical environments.

  5. Soil salinity evolution and its relationship with dynamics of groundwater in the oasis of inland river basins: case study from the Fubei region of Xinjiang Province, China.

    PubMed

    Wang, Yugang; Xiao, Duning; Li, Yan; Li, Xiaoyu

    2008-05-01

    Soil salinization is an important worldwide environmental problem, especially in arid and semi-arid regions. Knowledge of its temporal and spatial variability is crucial for the management of oasis agriculture. The study area has experienced dramatic change in the shallow groundwater table and soil salinization during the 20th century, especially in the past two decades. Classical statistics, geostatistics and geographic information system (GIS) were applied to estimate the spatial variability of the soil salt content in relation to the shallow groundwater table and land use from 1983 to 2005. Consumption of reservoir water for agricultural irrigation was the main cause of a rise in the shallow groundwater table under intense evapotranspiration conditions, and this led indirectly to soil salinization. The area of soil salt accumulation was greater in irrigated than in non-irrigated landscape types with an increasing of 40.04% from 1983 to 2005 in cropland at approximately 0.43 t ha(-1) year(-1), and an increase at approximately 0.68 t ha(-1) year(-1) in saline alkaline land. Maps of the shallow groundwater table in 1985 and 2000 were used to deduce maps for 1983 and 1999, respectively, and the registration accuracy was 99%.

  6. Extreme environments in the critical zone: Linking acidification hazard of acid sulfate soils in mound spring discharge zones to groundwater evolution and mantle degassing.

    PubMed

    Shand, Paul; Gotch, Travis; Love, Andrew; Raven, Mark; Priestley, Stacey; Grocke, Sonia

    2016-10-15

    A decrease in flow from the iconic travertine mound springs of the Great Artesian Basin in South Australia has led to the oxidation of hypersulfidic soils and extreme soil acidification, impacting their unique groundwater dependent ecosystems. The build-up of pyrite in these systems occurred over millennia by the discharge of deep artesian sulfate-containing groundwaters through organic-rich subaqueous soils. Rare iron and aluminium hydroxysulfate minerals form thick efflorescences due to high evaporation rates in this arid zone environment, and the oxidised soils pose a significant risk to local aquatic and terrestrial ecosystems. The distribution of extreme acidification hazard is controlled by regional variations in the hydrochemistry of groundwater. Geochemical processes fractionate acidity and alkalinity into separate parts of the discharge zone allowing potentially extreme environments to form locally. Differences in groundwater chemistry in the aquifer along flow pathways towards the spring discharge zone are related to a range of processes including mineral dissolution and redox reactions, which in turn are strongly influenced by degassing of the mantle along deep crustal fractures. There is thus a connection between shallow critical zone ecosystems and deep crustal/mantle processes which ultimately control the formation of hypersulfidic soils and the potential for extreme geochemical environments. PMID:27256909

  7. Distinct effects of moisture and air contents on acoustic properties of sandy soil.

    PubMed

    Oshima, Takuya; Hiraguri, Yasuhiro; Okuzono, Takeshi

    2015-09-01

    Knowledge of distinct effects of moisture content and air volume on acoustic properties of soil is sought to predict the influence of human activities such as cultivation on acoustic propagation outdoors. This work used an impedance tube with the two-thickness method to investigate such effects. For a constant moisture weight percentage, the magnitude of the characteristic impedance became smaller and the absorption coefficient became higher with increase of the air space ratio. For a constant air space ratio, the absorption coefficient became larger and the magnitude of the propagation constant became smaller with increasing moisture weight percentage. PMID:26428823

  8. Heat transfer Effect by soil temperature changes under shallow groundwater in the Mu Us desert, Northern China

    NASA Astrophysics Data System (ADS)

    Qiao, X.; Lu, R.; Donghui, C.

    2015-12-01

    Soil temperature change is principle elements to biological growth, soil freeze or thawing process. A situ field was conducted in the Mu Us desert of Wushen Qi County, Inner Mongolia, to mainly monitor soil temperature, moisture content and groundwater level. The unconfined aquifer constituted by Quaternary fine eolian sand, groundwater level is 125cm. This paper, choosing date from May 1, 2013 to April 30, 2014, soil day temperature is conducted by 3:00, 6:00,till 24:00, vertical spacing including 2cm,5 cm、10 cm、15 cm、20 cm, 75cm,125cm,which its symbol is T10, T15, T20, T75, T125 respectively. Here, surface layer temperature TS calculated by soil temperature of 2-5cm depth. Due to only 5 minutes interval, this state was taken as a state one. (1) soil temperature has mixture change on surface layer and its temperature different is over 35 ℃. (2) Surface layer temperature changes of every month have three stages and its conducted heat, which calculated between TS and T10. Since TS exceeds T10 and heat transfer direction is from surface to underground in May, June and July 2013, even heat transfer amounts reduced by participation in July. However, TS is inferior to T10 and conduced heat direction reverse in August till to February 2014.Continually conduced heat start to next circulation and then it's heat direction from surface to underground due to TS exceeds T10 again in March and April 2014. (3) Temperature changes of phreatic water table every month have also three stages and its conducted heat which calculated between T75 and T125, heat transfer direction from unsaturated zone to saturated zone due to T75 exceeds T125 from May till middle September 2013. However, T75 is inferior to T125 and heat direction reverse from late September 2013 till May 2014, but conduced heat direction starts to change from unsaturated zone to saturated zone again in early April 2014.The result can imply shallow gruondwater has some contribution to surface layer temperature in

  9. Influence of Temperature, Relative Humidity, and Soil Properties on the Soil-Air Partitioning of Semivolatile Pesticides: Laboratory Measurements and Predictive Models.

    PubMed

    Davie-Martin, Cleo L; Hageman, Kimberly J; Chin, Yu-Ping; Rougé, Valentin; Fujita, Yuki

    2015-09-01

    Soil-air partition coefficient (Ksoil-air) values are often employed to investigate the fate of organic contaminants in soils; however, these values have not been measured for many compounds of interest, including semivolatile current-use pesticides. Moreover, predictive equations for estimating Ksoil-air values for pesticides (other than the organochlorine pesticides) have not been robustly developed, due to a lack of measured data. In this work, a solid-phase fugacity meter was used to measure the Ksoil-air values of 22 semivolatile current- and historic-use pesticides and their degradation products. Ksoil-air values were determined for two soils (semiarid and volcanic) under a range of environmentally relevant temperature (10-30 °C) and relative humidity (30-100%) conditions, such that 943 Ksoil-air measurements were made. Measured values were used to derive a predictive equation for pesticide Ksoil-air values based on temperature, relative humidity, soil organic carbon content, and pesticide-specific octanol-air partition coefficients. Pesticide volatilization losses from soil, calculated with the newly derived Ksoil-air predictive equation and a previously described pesticide volatilization model, were compared to previous results and showed that the choice of Ksoil-air predictive equation mainly affected the more-volatile pesticides and that the way in which relative humidity was accounted for was the most critical difference.

  10. Influence of Temperature, Relative Humidity, and Soil Properties on the Soil-Air Partitioning of Semivolatile Pesticides: Laboratory Measurements and Predictive Models.

    PubMed

    Davie-Martin, Cleo L; Hageman, Kimberly J; Chin, Yu-Ping; Rougé, Valentin; Fujita, Yuki

    2015-09-01

    Soil-air partition coefficient (Ksoil-air) values are often employed to investigate the fate of organic contaminants in soils; however, these values have not been measured for many compounds of interest, including semivolatile current-use pesticides. Moreover, predictive equations for estimating Ksoil-air values for pesticides (other than the organochlorine pesticides) have not been robustly developed, due to a lack of measured data. In this work, a solid-phase fugacity meter was used to measure the Ksoil-air values of 22 semivolatile current- and historic-use pesticides and their degradation products. Ksoil-air values were determined for two soils (semiarid and volcanic) under a range of environmentally relevant temperature (10-30 °C) and relative humidity (30-100%) conditions, such that 943 Ksoil-air measurements were made. Measured values were used to derive a predictive equation for pesticide Ksoil-air values based on temperature, relative humidity, soil organic carbon content, and pesticide-specific octanol-air partition coefficients. Pesticide volatilization losses from soil, calculated with the newly derived Ksoil-air predictive equation and a previously described pesticide volatilization model, were compared to previous results and showed that the choice of Ksoil-air predictive equation mainly affected the more-volatile pesticides and that the way in which relative humidity was accounted for was the most critical difference. PMID:26258946

  11. Groundwater transit time distribution and transfer of nitrates from soils to river network

    NASA Astrophysics Data System (ADS)

    Michalczyk, Tomasz; Bar-Michalczyk, Dominika; Duliński, Marek; Kania, Jarosław; Malina, Grzegorz; Różański, Kazimierz; Szklarczyk, Tadeusz; Wachniew, Przemysław; Witczak, Stanisław; Zięba, Damian; Żurek, Anna

    2016-04-01

    Measures undertaken to reduce nitrate loadings of agricultural origin to surface waters have to take into account delays associated with pollution transport between the root zone and groundwater abstraction wells or natural discharge zones. Parts of an important fissured-carbonate aquifer (Major Groundwater Basin No. 326) located in southern Poland are polluted, with concentrations of nitrates significantly exceeding the European Union limit of 50 mg/L. The polluted groundwater discharges to the streams of the Kocinka river catchment affecting their water quality. The MODFLOW and MT3DMS codes were used to model flow and transport of contaminants in the aquifer. Transport of conservative solutes was performed in a transient mode, with the steady-state flow field calibrated using present-day distribution of hydraulic heads and discharges of streams draining the aquifer. Time series of tritium data available for 21 production wells and springs, some of them extending over the period of 30 years, were used for calibration of flow and transport model resulting in significant changes in the original conceptual framework of this groundwater system. The regional-scale numerical model of flow and transport allowed for identification of the gaining stream reaches and for estimation of groundwater contributions to streamflow. Observations of in stable isotope composition and stream water chemistry confirmed the results of the numerical model for these particular stream reaches. The numerical model provided also the transit time distribution of groundwater flow through the saturated zone with an average value of 8 years and dominant transit times in the range from 3 to 20 years. Transit times of water through the unsaturated zone are in the range from less than 5 to 25 years with an average value of 10 years. Because of these delays, the results of measures aimed at reducing nitrate loads to the river network will be visible only within the relevant timescales.

  12. Air pollution: Household soiling and consumer welfare losses

    USGS Publications Warehouse

    Watson, W.D.; Jaksch, J.A.

    1982-01-01

    This paper uses demand and supply functions for cleanliness to estimate household benefits from reduced particulate matter soiling. A demand curve for household cleanliness is estimated, based upon the assumption that households prefer more cleanliness to less. Empirical coefficients, related to particulate pollution levels, for shifting the cleanliness supply curve, are taken from available studies. Consumer welfare gains, aggregated across 123 SMSAs, from achieving the Federal primary particulate standard, are estimated to range from $0.9 to $3.2 million per year (1971 dollars). ?? 1982.

  13. MEASUREMENT OF EFFECTIVE AIR DIFFUSION COEFFICIENTS FOR TRICHLOROETHENE IN UNDISTURBED SOIL CORES. (R826162)

    EPA Science Inventory

    Abstract

    In this study, we measure effective diffusion coefficients for trichloroethene in undisturbed soil samples taken from Picatinny Arsenal, New Jersey. The measured effective diffusion coefficients ranged from 0.0053 to 0.0609 cm2/s over a range of air...

  14. Dry deposition and soil-air gas exchange of polychlorinated biphenyls (PCBs) in an industrial area.

    PubMed

    Bozlaker, Ayse; Odabasi, Mustafa; Muezzinoglu, Aysen

    2008-12-01

    Ambient air and dry deposition, and soil samples were collected at the Aliaga industrial site in Izmir, Turkey. Atmospheric total (particle+gas) Sigma(41)-PCB concentrations were higher in summer (3370+/-1617 pg m(-3), average+SD) than in winter (1164+/-618 pg m(-3)), probably due to increased volatilization with temperature. Average particulate Sigma(41)-PCBs dry deposition fluxes were 349+/-183 and 469+/-328 ng m(-2) day(-1) in summer and winter, respectively. Overall average particulate deposition velocity was 5.5+/-3.5 cm s(-1). The spatial distribution of Sigma(41)-PCB soil concentrations (n=48) showed that the iron-steel plants, ship dismantling facilities, refinery and petrochemicals complex are the major sources in the area. Calculated air-soil exchange fluxes indicated that the contaminated soil is a secondary source to the atmosphere for lighter PCBs and as a sink for heavier ones. Comparable magnitude of gas exchange and dry particle deposition fluxes indicated that both mechanisms are equally important for PCB movement between air and soil in Aliaga.

  15. Uptake of polychlorinated biphenyls and organochlorine pesticides from soil and air into radishes (Raphanus sativus).

    PubMed

    Mikes, Ondrej; Cupr, Pavel; Trapp, Stefan; Klanova, Jana

    2009-02-01

    Uptake of organochlorine pesticides and polychlorinated biphenyls from soil and air into radishes was measured at a heavily contaminated field site. The highest contaminant concentrations were found for DDT and its metabolites, and for beta-hexachlorocyclohexane. Bioconcentration factor (BCF, defined as a ratio between the contaminant concentration in the plant tissue and concentration in soil) was determined for roots, edible bulbs and shoots. Root BCF values were constant and not correlated to log K(OW). A negative correlation between BCF and log K(OW) was found for edible bulbs. Shoot BCF values were rather constant and varied between 0.01 and 0.22. Resuspended soil particles may facilitate the transport of chemicals from soil to shoots. Elevated POP concentrations found in shoots of radishes grown in the control plot support the hypothesis that the uptake from air was more significant for shoots than the one from soil. The uptake of POPs from air was within the range of theoretical values predicted from log K(OA).

  16. Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

    NASA Astrophysics Data System (ADS)

    Cuthbert, M. O.; Mackay, R.; Nimmo, J. R.

    2012-07-01

    Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is developed and tested using a range of numerical models, including a modified soil moisture balance model (SMBM) for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via macropore flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in the macropore system due to seasonal ploughing of the topsoil, and a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010) is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

  17. Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

    NASA Astrophysics Data System (ADS)

    Cuthbert, M. O.; Mackay, R.; Nimmo, J. R.

    2013-03-01

    Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is presented and tested using a range of numerical models, including a modified soil moisture balance model (SMBM) for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via preferential flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in preferential flow pathways due to seasonal ploughing of the topsoil and to a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010) is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

  18. An evaluation of remote sensing derived soil pH and average spring groundwater table for ecological assessments

    NASA Astrophysics Data System (ADS)

    Roelofsen, Hans D.; van Bodegom, Peter M.; Kooistra, Lammert; van Amerongen, Jorg J.; Witte, Jan-Philip M.

    2015-12-01

    Ecological assessments such as species distribution modelling and benchmarking site quality towards regulations often rely on full spatial coverage information of site factors such as soil acidity, moisture regime or nutrient availability. To determine if remote sensing (RS) is a viable alternative to traditional data sources of site factor estimates, we analysed the accuracy (using ground truth validation measurements) of traditional and RS sources of pH and mean spring groundwater level (MSL, in m) estimates. Traditional sources were a soil map and hydrological model. RS estimates were obtained using vegetation indicator values (IVs) from a Dutch national system as an intermediate between site factors and spectral response. IVs relate to those site factors that dictate vegetation occurrence, whilst also providing a robust link to canopy spectra. For pH, the soil map and the RS estimate were nearly as accurate. For MSL, the RS estimates were much closer to the observed groundwater levels than the hydrological model, but the error margin of the estimates still exceeded the tolerance range of moisture sensitive vegetation. The relatively high accuracy of the RS estimates was made possible by the availability of local calibration points and large environmental gradients in the study site. In addition, the error composition of the RS estimates could be analysed step-by-step, whereas the traditional sources had to be accepted 'as-is'. Also considering that RS offers high spatial and temporal resolution at low costs, RS offered advantages over traditional sources. This will likely hold true for any other situation where prerequisites of accurate RS estimates have been met.

  19. Linking soil moisture balance and source-responsive models to estimate diffuse and preferential components of groundwater recharge

    USGS Publications Warehouse

    Cuthbert, M.O.; Mackay, R.; Nimmo, J.R.

    2012-01-01

    Results are presented of a detailed study into the vadose zone and shallow water table hydrodynamics of a field site in Shropshire, UK. A conceptual model is developed and tested using a range of numerical models, including a modified soil moisture balance model (SMBM) for estimating groundwater recharge in the presence of both diffuse and preferential flow components. Tensiometry reveals that the loamy sand topsoil wets up via macropore flow and subsequent redistribution of moisture into the soil matrix. Recharge does not occur until near-positive pressures are achieved at the top of the sandy glaciofluvial outwash material that underlies the topsoil, about 1 m above the water table. Once this occurs, very rapid water table rises follow. This threshold behaviour is attributed to the vertical discontinuity in the macropore system due to seasonal ploughing of the topsoil, and a lower permeability plough/iron pan restricting matrix flow between the topsoil and the lower outwash deposits. Although the wetting process in the topsoil is complex, a SMBM is shown to be effective in predicting the initiation of preferential flow from the base of the topsoil into the lower outwash horizon. The rapidity of the response at the water table and a water table rise during the summer period while flow gradients in the unsaturated profile were upward suggest that preferential flow is also occurring within the outwash deposits below the topsoil. A variation of the source-responsive model proposed by Nimmo (2010) is shown to reproduce the observed water table dynamics well in the lower outwash horizon when linked to a SMBM that quantifies the potential recharge from the topsoil. The results reveal new insights into preferential flow processes in cultivated soils and provide a useful and practical approach to accounting for preferential flow in studies of groundwater recharge estimation.

  20. Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site—10281

    SciTech Connect

    Waugh, W.J.; Miller, D.E.; Morris, S.A.; Sheader, L.R.; Glenn, E.P.; Moore, D.; Carroll, K.C.; Benally, L.; Roanhorse, M.; Bush, R.P.; none,

    2010-03-07

    The U.S. Department of Energy (DOE), the Navajo Nation, and the University of Arizona are exploring natural and enhanced attenuation remedies for groundwater contamination at a former uranium-ore processing site near Monument Valley, Arizona. DOE removed radioactive tailings from the Monument Valley site in 1994. Nitrate and ammonium, waste products of the milling process, remain in an alluvial groundwater plume spreading from the soil source where tailings were removed. Planting and irrigating two native shrubs, fourwing saltbush and black greasewood, markedly reduced both nitrate and ammonium in the source area over an 8-year period. Total nitrogen dropped from 350 mg/kg in 2000 to less than 200 mg/kg in 2008. Most of the reduction is attributable to irrigation-enhanced microbial denitrification rather than plant uptake. However, soil moisture and percolation flux monitoring show that the plantings control the soil water balance in the source area, preventing additional leaching of nitrogen compounds. Enhanced denitrification and phytoremediation also look promising for plume remediation. Microcosm experiments, nitrogen isotopic fractionation analysis, and solute transport modeling results suggest that (1) up to 70 percent of nitrate in the plume has been lost through natural denitrification since the mill was closed in 1968, and (2) injection of ethanol may accelerate microbial denitrification in plume hot spots. A field-scale ethanol injection pilot study is underway. Landscape-scale remote sensing methods developed for the project suggest that transpiration from restored native phreatophyte populations rooted in the aquifer could limit further expansion of the plume. An evaluation of landfarm phytoremediation, the irrigation of native shrub plantings with high nitrate water pumped from the alluvial aquifer, is also underway.

  1. Community perspectives on the risk of indoor air pollution arising from contaminated groundwater.

    PubMed

    Johnston, Jill E; Kramer, Amanda J; Gibson, Jacqueline MacDonald

    2015-05-01

    The migration of volatile contaminants into overlying buildings, known as vapor intrusion, is a health concern for people living above contaminated groundwater. As public health and environmental agencies develop protocols to evaluate vapor intrusion exposure, little attention has been paid to the experiences and opinions of communities likely to be affected by vapor intrusion. Using a community-driven research approach and qualitative interviews, we explored community perspectives on the vapor intrusion pathway and the perceived impact on community health and well-being among neighbors living atop a large, shallow-chlorinated solvent plume in San Antonio, TX. Most participants associated vapor intrusion with health risks, expressing concern about the unavoidable and uncontrollable nature of their exposure. Few were satisfied with the responsiveness of public officials. Above all, participants wanted more accurate, transparent information and additional independent scientific investigations.

  2. Community perspectives on the risk of indoor air pollution arising from contaminated groundwater.

    PubMed

    Johnston, Jill E; Kramer, Amanda J; Gibson, Jacqueline MacDonald

    2015-05-01

    The migration of volatile contaminants into overlying buildings, known as vapor intrusion, is a health concern for people living above contaminated groundwater. As public health and environmental agencies develop protocols to evaluate vapor intrusion exposure, little attention has been paid to the experiences and opinions of communities likely to be affected by vapor intrusion. Using a community-driven research approach and qualitative interviews, we explored community perspectives on the vapor intrusion pathway and the perceived impact on community health and well-being among neighbors living atop a large, shallow-chlorinated solvent plume in San Antonio, TX. Most participants associated vapor intrusion with health risks, expressing concern about the unavoidable and uncontrollable nature of their exposure. Few were satisfied with the responsiveness of public officials. Above all, participants wanted more accurate, transparent information and additional independent scientific investigations. PMID:25815742

  3. Mercury in soil gas and air--A potential tool in mineral exploration

    USGS Publications Warehouse

    McCarthy, Joseph Howard; Vaughn, W.W.; Learned, R.E.; Meuschke, J.L.

    1969-01-01

    The mercury content in soil gas and in the atmosphere was measured in several mining districts to test the possibility that the mercury content in the atmosphere is higher over ore deposits than over barren ground. At Cortez, Nev., the distribution of anorhalous amounts of mercury in the air collected at ground level (soil gas) correlates well with the distribution of gold-bearing rocks that are covered by as much as 100 feet of gravel. The mercury content in the atmosphere collected at an altitude of 200 feet by an aircraft was 20 times background over a mercury posit and 10 times background over two porphyry copper deposits. Measurement of mercury in soil gas and air may prove to be a valuable exploration tool.

  4. Screening the environmental fate of organic contaminants in sewage sludges applied to agricultural soils: 1. The potential for downward movement to groundwaters.

    PubMed

    Wilson, S C; Duarte-Davidson, R; Jones, K C

    1996-06-21

    The potential for organic contaminants present in sewage sludge to leach and cause groundwater contamination following sludge application to agricultural land has been assessed. Models used to predict compound mobility in soil on the basis of physico-chemical parameters were applied to a range of contaminants prioritised and/or detected in sludge and a provisional list of potential "leachers' compiled. In addition, theoretical soil water concentrations following sludge application were calculated using mean reported sludge contaminant concentrations and soil/water partition coefficients. These estimated aqueous phase concentrations were compared with Dutch groundwater quality standards in the absence of appropriate UK standards to identify those compounds which could be present in groundwater at levels of concern. The two prioritised lists were used to identify compounds in sludge which could pose a possible threat to groundwater. Appropriate experimental data were not available to qualify model results. However, the screening exercise indicated that under routine operation practice with typical sludge application rates, and the usual range of compound concentrations detected in sludge, groundwater quality standards were unlikely to be exceeded. However, data variability, reliability and scarcity limited the usefulness of this screening approach.

  5. Detection of semi-volatile organic compounds (SVOCs) in surface water, soil, and groundwater in a chemical industrial park in Eastern China.

    PubMed

    Liu, Benhua; Li, Yuehua; Ma, Jianfeng; Huang, Linxian; Chen, Liang

    2016-01-01

    China is suffering from serious water and soil pollution, especially in the North China Plain. This work investigated semi-volatile organic compounds (SVOCs) in surface water, groundwater and soil within a chemical industrial park in Eastern China, for which the volatile organic compound (VOC) results have been previously reported. A total of 20 samples were collected from the field, and analyzed in the laboratory. A 100% detection frequency of SVOCs in samples from this chemical industrial park was observed (same as VOCs). Moreover, the detection frequency of 113 SVOCs in each sample reached 15.93, 12.39 and 20.35% for surface water, groundwater and soil, respectively. The most detected SVOCs in the park included N-containing SVOCs, polycyclic aromatic hydrocarbons, phthalates, organic pesticides and polychlorodiphenyls. The elevated detecting frequencies and concentration levels of SVOCs identified in the groundwater were attributed to the intensive chemical production activities in the park. In addition, the agricultural activities in the area might also have contributed to the SVOCs to the groundwater. The results of VOCs and SVOCs from this and previous studies suggest that the groundwater in this industrial park has been severely contaminated, and the contamination likely spreads beyond the park. Imminent hydrogeological assessments and remedial actions are warranted to eliminate the source and mitigate the potential plume expansion beyond the park boundary.

  6. Reducing compaction effort and incorporating air permeability in Proctor testing for design of urban green spaces on cohesive soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is well established that compaction negatively affects agronomic productivity, that air permeability is a sensitive measure of the degree of soil compaction and therefore a good indicator of soil productivity impairment from compaction. Cohesive soils in urban settings are often heavily compacted...

  7. Evaluating Adult Groundwater Education.

    ERIC Educational Resources Information Center

    Gerakis, Argyrios

    1998-01-01

    One-day groundwater education workshops held to educate soil conservation personnel were assessed for effect on participant knowledge using a quasiexperimental design. Participants were tested on their groundwater knowledge and attitude toward groundwater conservation before and after the training. Participant scores improved significantly in only…

  8. Remediation of arsenic contaminated soil by coupling oxalate washing with subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Ye, Yuanyao; Chen, Jing; Lu, Xiaohua

    2016-02-01

    The application of a novel coupled process with oxalate washing and subsequent zero-valent iron (ZVI)/Air treatment for remediation of arsenic contaminated soil was investigated in the present study. Oxalate is biodegradable and widely present in the environment. With addition of 0.1 mol L(-1) oxalate under circumneutral condition, 83.7% and 52.6% of arsenic could be removed from a spiked kaolin and an actual contaminated soil respectively. Much more oxalate adsorption on the actual soil was attributed to the higher soil organic matter and clay content. Interestingly, oxalate retained in the washing effluent could act as an organic ligand to promote the oxidation efficiency of ZVI/Air at near neutral pH. Compared with the absence of oxalate, much more As(III) was oxidized. Arsenic was effectively adsorbed on iron (hydr)oxides as the consumption of oxalate and the increase of pH value. For the actual soil washing effluent, about 94.9% of total arsenic was removed after 120 min's treatment without pH adjustment. It has been demonstrated that As(V) was the dominant arsenic speciation adsorbed on iron (hydr)oxides. This study provides a promising alternative for remediation of arsenic contaminated soil in view of its low cost and environmental benign. PMID:26476769

  9. Remediation of arsenic contaminated soil by coupling oxalate washing with subsequent ZVI/Air treatment.

    PubMed

    Cao, Menghua; Ye, Yuanyao; Chen, Jing; Lu, Xiaohua

    2016-02-01

    The application of a novel coupled process with oxalate washing and subsequent zero-valent iron (ZVI)/Air treatment for remediation of arsenic contaminated soil was investigated in the present study. Oxalate is biodegradable and widely present in the environment. With addition of 0.1 mol L(-1) oxalate under circumneutral condition, 83.7% and 52.6% of arsenic could be removed from a spiked kaolin and an actual contaminated soil respectively. Much more oxalate adsorption on the actual soil was attributed to the higher soil organic matter and clay content. Interestingly, oxalate retained in the washing effluent could act as an organic ligand to promote the oxidation efficiency of ZVI/Air at near neutral pH. Compared with the absence of oxalate, much more As(III) was oxidized. Arsenic was effectively adsorbed on iron (hydr)oxides as the consumption of oxalate and the increase of pH value. For the actual soil washing effluent, about 94.9% of total arsenic was removed after 120 min's treatment without pH adjustment. It has been demonstrated that As(V) was the dominant arsenic speciation adsorbed on iron (hydr)oxides. This study provides a promising alternative for remediation of arsenic contaminated soil in view of its low cost and environmental benign.

  10. [Effects of air temperature and soil moisture on flavonoids accumulation in Ginkgo biloba leaves].

    PubMed

    Wang, Gui-Bin; Guo, Xu-Qin; Chang, Li; Cao, Fu-Liang

    2013-11-01

    Taking the 2-year old Ginkgo biloba seedlings as test materials, a pot experiment was conducted in an artificial climate chamber to study the effects of air temperature and soil moisture on the flavonoids accumulation in leaves. Three levels of air temperature (15/5 degrees C, 25/15 degrees C, and 35/25 degrees C day/night) and three levels of soil moisture (55%-60%, 40%-45%, and 30%-35% of field capacity) were installed, yielding nine temperature-soil moisture combinations. Under the three levels of soil moisture, the quercetin, kaempferol, isorhamnetin, and total flavonoids contents in the leaves were higher at 15/5 degrees C than at 25/15 degrees C and 35/25 degrees C. Soil moisture had minor effects on the flavonoids accumulation. The leaf kaempferol content was the highest, followed by quercetin and isorhamnetin. The total flavonoids yield per plant at 35/25 degrees C was higher than that at 15/5 degrees C and 25/15 degrees C. It was suggested that to adopt appropriate soil covering and watering before harvesting to decrease the ambient temperature could benefit the enhancement of leaf flavonoids content and the improvement of per unit area flavonoids production in G. biloba leaf-harvesting plantation.

  11. Impacts of Agriculture on Nitrates in Soil and Groundwater in the Southeastern Coastal Plain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen (N) contamination of surface and groundwater is a health concern for both humans and animals. Excess N in surface water bodies may contribute to eutrophication. Elevated nitrate (NO3-N) concentrations in drinking water have caused infant death from the disease methemoglobinemia. Nitrates...

  12. Air stripping. January 1980-February 1992 (Citations from the NTIS Data Base). Rept. for Jan 80-Feb 92

    SciTech Connect

    Not Available

    1992-02-01

    The bibliography contains citations concerning the application of air stripping techniques to water treatment, including groundwater decontamination and wastewater purification. The advantages and disadvantages of air stripping over other water treatment processes are discussed. Cleanup of the organic emissions generated by air stripping is also considered. The primary applications of air stripping are in groundwater and soil cleanup. (Contains 58 citations with title list and subject index.)

  13. Assessment of groundwater, soil-gas, and soil contamination at the Vietnam Armor Training Facility, Fort Gordon, Georgia, 2009-2011

    USGS Publications Warehouse

    Guimaraes, Wladmir B.; Falls, W. Fred; Caldwell, Andral W.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the groundwater, soil gas, and soil for contaminants at the Vietnam Armor Training Facility (VATF) at Fort Gordon, from October 2009 to September 2011. The assessment included the detection of organic compounds in the groundwater and soil gas, and inorganic compounds in the soil. In addition, organic contaminant assessment included organic compounds classified as explosives and chemical agents in selected areas. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. This report is a revision of "Assessment of soil-gas, surface-water, and soil contamination at the Vietnam Armor Training Facility, Fort Gordon, Georgia, 2009-2010," Open-File Report 2011-1200, and supersedes that report to include results of additional samples collected in July 2011. Four passive samplers were deployed in groundwater wells at the VATF in Fort Gordon. Total petroleum hydrocarbons and benzene and octane were detected above the method detection level at all four wells. The only other volatile organic compounds detected above their method detection level were undecane and pentadecane, which were detected in two of the four wells. Soil-gas samplers were deployed at 72 locations in a grid pattern across the VATF on June 3, 2010, and then later retrieved on June 9, 2010. Total petroleum hydrocarbons were detected in 71 of the 72 samplers (one sampler was destroyed in the field and not analyzed) at levels above the method detection level, and the combined mass of benzene, toluene, ethylbenzene, and total xylene (BTEX) was detected above the detection level in 31 of the 71 samplers that were analyzed. Other volatile organic compounds

  14. Assessment of groundwater, soil-gas, and soil contamination at the Vietnam Armor Training Facility, Fort Gordon, Georgia, 2009-2011

    USGS Publications Warehouse

    Guimaraes, Wladmir B.; Falls, W. Fred; Caldwell, Andral W.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2012-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, Georgia, assessed the groundwater, soil gas, and soil for contaminants at the Vietnam Armor Training Facility (VATF) at Fort Gordon, from October 2009 to September 2011. The assessment included the detection of organic compounds in the groundwater and soil gas, and inorganic compounds in the soil. In addition, organic contaminant assessment included organic compounds classified as explosives and chemical agents in selected areas. The assessment was conducted to provide environmental contamination data to the U.S. Army at Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. This report is a revision of "Assessment of soil-gas, surface-water, and soil contamination at the Vietnam Armor Training Facility, Fort Gordon, Georgia, 2009-2010," Open-File Report 2011-1200, and supersedes that report to include results of additional samples collected in July 2011. Four passive samplers were deployed in groundwater wells at the VATF in Fort Gordon. Total petroleum hydrocarbons and benzene and octane were detected above the method detection level at all four wells. The only other volatile organic compounds detected above their method detection level were undecane and pentadecane, which were detected in two of the four wells. Soil-gas samplers were deployed at 72 locations in a grid pattern across the VATF on June 3, 2010, and then later retrieved on June 9, 2010. Total petroleum hydrocarbons were detected in 71 of the 72 samplers (one sampler was destroyed in the field and not analyzed) at levels above the method detection level, and the combined mass of benzene, toluene, ethylbenzene, and total xylene (BTEX) was detected above the detection level in 31 of the 71 samplers that were analyzed. Other volatile organic compounds

  15. Estimation of the release and migration of lead through soils and groundwater at the Hanford Site 218-E-12B Burial Ground. Volume 1, Final report

    SciTech Connect

    Rhoads, K.; Bjornstad, B.N.; Lewis, R.E.; Teel, S.S.; Cantrell, K.J.; Serne, R.J.; Smoot, J.L.; Kincaid, C.T.; Wurstner, S.K.

    1992-10-01

    This study was performed to evaluate the potential for transport of lead from the Hanford Site 218-E-12B Burial Ground to the surrounding surface- and groundwater. Burial of metal components containing nickel alloy steel and lead at this location may eventually result in release of lead to the subsurface environment, including groundwater aquifers that may be used for domestic and agricultural purposes in the future and, ultimately, to the Columbia River. The rate at which lead is transported to downgradient locations depends on a complex set of factors, such as climate, soil and groundwater chemistry, and the geologic and hydrologic configuration of the subsurface region between the burial ground and a potential receptor location. The groundwater transport analysis was conducted using a one-dimensional screening model with a relatively conservative matrix of parameters obtained from the hydrogeologic and geochemical studies.

  16. Estimation of the release and migration of lead through soils and groundwater at the Hanford Site 218-E-12B Burial Ground

    SciTech Connect

    Rhoads, K.; Bjornstad, B.N.; Lewis, R.E.; Teel, S.S.; Cantrell, K.J.; Serne, R.J.; Smoot, J.L.; Kincaid, C.T.; Wurstner, S.K.

    1992-10-01

    This study was performed to evaluate the potential for transport of lead from the Hanford Site 218-E-12B Burial Ground to the surrounding surface- and groundwater. Burial of metal components containing nickel alloy steel and lead at this location may eventually result in release of lead to the subsurface environment, including groundwater aquifers that may be used for domestic and agricultural purposes in the future and, ultimately, to the Columbia River. The rate at which lead is transported to downgradient locations depends on a complex set of factors, such as climate, soil and groundwater chemistry, and the geologic and hydrologic configuration of the subsurface region between the burial ground and a potential receptor location. The groundwater transport analysis was conducted using a one-dimensional screening model with a relatively conservative matrix of parameters obtained from the hydrogeologic and geochemical studies.

  17. Accumulation of Metals in Soils, Groundwater and Edible Parts of Crops Grown Under Long-Term Irrigation with Sewage Mixed Industrial Effluents.

    PubMed

    Yadav, R K; Minhas, P S; Lal, Khajanchi; Chaturvedi, R K; Yadav, Gajender; Verma, T P

    2015-08-01

    Farmers in developing countries irrigate crops using raw urban and industrial effluents with consequent risks from metal contamination. Therefore, soils, crops and groundwater from an effluent irrigation use site were assessed for Cd, Cr, Ni and Pb. Total and available contents of metals in soil followed the order Pb>Ni>Cr>Cd. Crops accumulated more Pb, followed by Cd, Ni and Cr. Pb exceeded the permissible limit with wastewater irrigation only, but Cd exceeded the limit even with combined irrigations of wastewater and groundwater. Among crops, sugar beet assimilated highest Cd (3.14 μg g(-1)) and Pb (6.42 μg g(-1)) concentrations. Legumes accumulated more metals than cereals. Long-term use of wastewater and its conjunctive use with groundwater led to toxic accumulations of Cd, Pb, Ni and Cr. Cd with higher availability and mobility indices and lower toxicity limit, posed the maximum risk of food-chain contamination.

  18. A new approach for the in situ determination of soil water retention characteristics for shallow groundwater systems

    NASA Astrophysics Data System (ADS)

    Dettmann, Ullrich; Bechtold, Michel

    2015-04-01

    Obtaining representative effective hydraulic properties for the pedon to field scale as input for models is a major challenge in hydrology. Hydraulic properties are often determined by laboratory measurements on small soil cores. Due to the high small-scale variability, many samples are needed to obtain representative values, which is time consuming and costly. Here, we present a new approach which is focused on the in situ determination of the soil water retention characteristics that is applicable to shallow groundwater systems. The method integrates over small-scale heterogeneity (appr. several meters) and uses only precipitation and water-level data. Our approach is built on two assumptions: i) for shallow groundwater systems (with water table depths of appr. < 0.5 to 1 m) , e.g. wetlands, with med