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Sample records for air soil groundwater

  1. In situ air sparging for bioremediation of groundwater and soils

    SciTech Connect

    Lord, D.; Lei, J.; Chapdelaine, M.C.; Sansregret, J.L.; Cyr, B.

    1995-12-31

    Activities at a former petroleum products depot resulted in the hydrocarbon contamination of soil and groundwater over a 30,000-m{sup 2} area. Site remediation activities consisted of three phases: site-specific characterization and treatability study, pilot-scale testing, and full-scale bioremediation. During Phase 1, a series of site/soil/waste characterizations was undertaken to ascertain the degree of site contamination and to determine soil physical/chemical and microbiological characteristics. Treatability studies were carried out to simulate an air sparging process in laboratory-scale columns. Results indicated 42% mineral oil and grease removal and 94% benzene, toluene, ethylbenzene, and xylenes (BTEX) removal over an 8-week period. The removal rate was higher in the unsaturated zone than in the saturated zone. Phase 2 involved pilot-scale testing over a 550-m{sup 2} area. The radius of influence of the air sparge points was evaluated through measurements of dissolved oxygen concentrations in the groundwater and of groundwater mounding. A full-scale air sparging system (Phase 3) was installed on site and has been operational since early 1994. Physical/chemical and microbiological parameters, and contaminants were analyzed to evaluate the system performance.

  2. 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.

  3. 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

  4. Optimized air sparging coupled with soil vapor extraction to remediate groundwater

    SciTech Connect

    Martinson, M.; Linck, J.; Manz, C.; Petrofske, T.

    1995-12-31

    Air sparging coupled with soil vapor extraction (AS/SVE) has obvious benefits for groundwater contamination consisting of volatile organic compounds, particularly benzene, ethylbenzene, toluene, and xylenes (BTEX). Although AS/SVE is easily employed given suitable site conditions, optimized AS/SVE system operation and monitoring (O/M) are often overlooked once treatment is initiated. Site O/M typically is conducted with on-site field staff, or as an alternative, by remotely connecting to the site via modem and programmable logic controller (PLC). Two AS/SVE sites located in Wisconsin have used either traditional on-site O/M or the remote modem/PLC option to evaluate and optimize system operation. System on-time efficiency using remote telemetry was improved compared to traditional O/M and system operations.

  5. Superfund record of decison (EPA Region 2): Naval Air Engineering Center, Area C soil and groundwater, Lakehurst, NJ, February 20, 1996

    SciTech Connect

    1996-08-01

    The decision document presents the selected alternative to address Area C soil and groundwater at the Naval Air Engineering Station in Lakehurst, New Jersey. The selected alternative to address groundwater at Area C is continued operation of the existing groundwater treatment facility with modifications to enhance system performance. For soil, the selected alternative for Site 10 is no further action. For Site 16 soil, the selected alternative is continued operation of the bioventing system with potential modifications to enhance system performance. For Site 17 soil, the selected alternative is continued operation of the soil vapor extraction and bioventing system with potential modifications to enhance system performance.

  6. 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.

  7. 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.

  8. 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.

  9. Viruses in soil and groundwater

    SciTech Connect

    Vaughn, J.M.; Landry, E.F.

    1981-01-01

    Human viruses usually gain access to soil systems through intentional or unintentional discharges of domestic wastewater. Intentional land treatment/disposal systems represent an attractive alternative to surface water discharges, providing both economic and environmental advantages. Major concerns over the possible threat to human health as a result of the large-scale use of such systems are as yet unresolved. One such concern involves the potential for viral contamination of groundwater systems which currently supply the drinking-water needs of half the United States population. While no groundwater-borne disease outbreaks of viral etiology have as yet been associated with land treatment use, the potential for their occurrence has been clearly indicated by epidemiological studies of outbreaks associated with groundwater pollution from unintentional modes of soil application. Epidemiological evidence has been supported by an increasing number of field studies which have demonstrated viral contamination of shallow aquifers resulting from the use of various land treatment modes, such as rapid infiltration/recharge systems. More recent studies have indicated that soil-associated microbial pollution of groundwater may be abated by the use of systems management practices based upon an understanding of the physical and chemical factors which influence viral retention in soil including: temperature; pH; moisture, clay and ion content; depth to groundwater; infiltration rate; and soil continuity. The proper manipulation of these principles in the operation of land treatment schemes which utilize high-quality wastewater effluents should provide the means for significantly diminishing the likelihood of viral movement to groundwater systems.

  10. 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.

  11. Integrated technologies for expedited soil and groundwater remediation

    SciTech Connect

    Lewis, R.; Wellman, D.

    1996-12-01

    A fast-track and economic approach was necessary to meet the needs of a property transfer agreement and to minimize impact to future usage of a site in the Los Angeles Basin. Woodward-Clyde responded by implementing site investigation, remedial action plan preparation for soil and groundwater, and selection and installation of remedial alternatives in an aggressive schedule of overlapped tasks. Assessment of soil and groundwater was conducted at the site, followed by design and construction of remediation systems. This phase of activity was completed within 2 years. Soil and groundwater were found to be impacted by chlorinated solvents and petroleum hydrocarbons. A vapor extraction system (2,000 scfm capacity) was installed for soil remediation, and an innovative air sparging system was installed for cost effective groundwater cleanup. A bioventing system was also applied in selected areas. The vapor extraction wellfield consists of 26 extraction and monitoring well points, with multiple screened casings. The air sparging wellfield consists of 32 sparging wells with a designed maximum flow of 400 scfm. The systems began operation in 1993, and have resulted in the estimated removal of approximately 30,000 pounds of contaminants, or about 90% of the estimated mass in place. The combined vapor extraction/air sparging system is expected to reduce the time for on-site groundwater remediation from 1/3 to 1/6 the time when compared to the conventional pump and treat method for groundwater remediation.

  12. 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.

  13. 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 ...

  14. 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.

  15. 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.

  16. In situ groundwater remediation using air sparging, vapor extraction and bioventing

    SciTech Connect

    Stumpf, P.; Cotton, D.W.; Bayliss, R.

    1994-12-31

    Over 60 years of refining operations have resulted in petroleum hydrocarbon contamination of soil and groundwater at the 74-acre former Golden Eagle Refinery in Carson, California. Successful negotiations with the California Regional Water Quality Control Board (RWQCB)-Los Angeles Region, and the California Department of Toxic Substances Control (DTSC) resulted in the use of a phased approach, separating the soil and groundwater remediation activities. Based on the findings of site assessments conducted to define and characterize the soil and groundwater contamination at the site, remediation of the soil was initiated first. By obtaining agency approval on the soil cleanup, the site could proceed with development during the groundwater remediation activities. Prior to groundwater remediation, an air sparging pilot test was performed at the site on a highly heterogeneous site consisting of mostly low permeability soils in southern California. This paper how the pilot test was performed, the test results and the accuracy of the results when scaled up to the full operating system.

  17. Frequently Asked Questions Regarding Management of Chlorinated Solvents in Soils and Groundwater

    DTIC Science & Technology

    2008-07-01

    groundwater systems Many are nonflammable Typically not a fire or explosion hazard Stable under natural aerobic conditions Slightly soluble in...Other established technologies include in situ vapor extraction, in situ air sparging, multi-phase extraction, surfactant flushing, and steam ...Soil mixing reduces or eliminates concerns about delivery of treatment material to affected zones. Combined with steam injection during auger mixing

  18. 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 ...

  19. 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

  20. Daytime and nighttime groundwater contributions to soils with different surface conditions

    NASA Astrophysics Data System (ADS)

    Xing, Xuguang; Ma, Xiaoyi; Shi, Wenjuan

    2015-12-01

    Contributions of groundwater to the soil-water balance play an important role in areas with shallow water tables. The characteristics of daytime and nighttime water flux using non-weighing lysimeters were studied from June to September 2012 and 2013 in the extremely arid Xinjiang Uyghur Autonomous Region in northwestern China. The study consisted of nine treatments: three surface conditions, bare soil and cotton plants, each with water tables at depths of 1.0, 1.5, and 2.0 m; and plastic mulch with a water table at 1.5 m but with three percentages of open areas (POAs) in the plastic. The groundwater supply coefficient (SC) and the groundwater contribution (GC) generally varied with surface conditions. Both SC and GC decreased in the bare-soil and cotton treatments with increasing depth of the groundwater. Both SC and GC increased in the plastic-mulch treatment with increasing POA. Average nighttime GCs in the bare-soil treatments in July and August (the midsummer months) were 50.8-60.8 and 53.2-65.3 %, respectively, of the total daily contributions. Average nighttime GCs in the cotton treatments in July and August were 51.4-60.2 and 51.5-58.1 %, respectively, of the total daily contributions. The average GCs in June and September, however, were lower at night than during the daytime. Soil temperature may thus play a more important role than air temperature in the upflow of groundwater.

  1. 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.

  2. 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.

  3. Soil and groundwater remediation: Asia, Oceania, and Africa

    SciTech Connect

    Huang, P.M.; Islandar, I.K.

    1999-11-01

    This book covers information on metals, radionuclides, other inorganics, pesticides, and other anthropogenic organic compounds in soil environments in Asia, Oceania, and Africa. It addresses the current status and future prospects on soil and groundwater pollution and the remediation strategies for years to come.

  4. 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).

  5. 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.

  6. 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.

  7. 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.

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

    PubMed

    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 Ca(2+), Mg(2+), 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.

  9. Groundwater and soil chemical changes under phreatophytic tree plantations

    NASA Astrophysics Data System (ADS)

    JobbáGy, Esteban G.; Jackson, Robert B.

    2007-06-01

    The onset of groundwater consumption by plants can initiate a pathway of chemical inputs from aquifers to ecosystems, typically absent in groundwater recharge areas. We explored this biogeochemical transfer and its influence on soils in phreatophytic eucalypt plantations and native grasslands of the Pampas (Argentina). Groundwater and soil chemical observations at three grassland/plantation pairs were complemented with more detailed analyses along a 400-m-long grassland-plantation transect. Although tree plantations showed a widespread and homogeneous salinization of groundwater and soils at all study sites, chemical contrasts between the plantation edge and core were evident along the study transect. Nonsalty, slightly acidic, bicarbonate-dominated waters in the grassland changed sharply within the plantation, with dissolved chloride, sulfate, calcium, and magnesium peaking at the plantation core (200 m away from the grassland) and dissolved sodium, carbonate, bicarbonate, and pH peaking toward the edge (0-50 m away from the grassland) and declining toward the core. In agreement with these differences, soil alkalinization was the strongest at the plantation edge but absent in the core. Groundwater flow simulations using FLOWNET suggested trajectories of increasing length and depth and older groundwater ages (confirmed by tritium analyses) toward the plantation core, explaining the hydrochemical contrasts within the plantation. Flow simulations and chloride mass balances suggested discharges of 250-500 mm yr-1 to the plantations. In our sites phreatophytic discharge controlled solute transfers from groundwater through (1) altered flow within the aquifer, affecting solute transport to the rooting zone, and (2) water uptake plus solute exclusion, concentrating solutes in the rooting zone. While the first mechanism may be restricted to the core of large phreatophytic areas, the second is likely to occur more generally in phreatophytic ecosystems.

  10. Chemical-specific representation of air--soil exchange and soil penetration in regional multimedia models.

    PubMed

    McKone, T E; Bennett, D H

    2003-07-15

    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 layers with different properties but a fixed boundary condition at the air-soil surface. The soil compartment algorithms can be dynamically linked to other compartments (air, vegetation, groundwater, 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.

  11. 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...

  12. 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.

  13. 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.

  14. Chemistry of trace elements in soils and groundwater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We present information about sources of processes that affect trace elements in soils and groundwater; precipitation and dissolution, surface interactions and absorption and oxidation-reduction reactions. For each element or group of elements, we provide a review of mode of occurrence, sources and ...

  15. 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.

  16. 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.

  17. 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

  18. Impact of recharge variations on water quality as indicated by excess air in groundwater of the Kalahari, Botswana

    NASA Astrophysics Data System (ADS)

    Osenbrück, Karsten; Stadler, Susanne; Sültenfuß, Jürgen; Suckow, Axel O.; Weise, Stephan M.

    2009-02-01

    Groundwater is an important and often exclusive water resource in arid and semi-arid regions. The aim of the present paper was to gain insight into the processes and conditions that control the deterioration of groundwater quality in the semi-arid Kalahari of Botswana. Measurements of 3He, 4He, 20Ne, 22Ne, and of 14C of dissolved inorganic carbon (DIC) were combined with existing isotopic and hydrochemical data to investigate groundwater from the Ntane Sandstone Aquifer, which is affected by high nitrate concentrations of non-anthropogenic origin. All groundwater samples revealed neon concentrations in excess to air-saturated water, which we attributed to the addition of excess air during recharge. Neon concentrations ranged from values close to air saturation for 14C DIC rich samples (up to 80.5%MC) up to values of 90% in excess to air-saturated water for lower 14C DIC contents (2.6-61.3%MC). A strong linear correlation of excess Ne with nitrate concentrations suggests an intimate connection between groundwater quality and the processes and conditions during groundwater recharge. Low groundwater recharge rates under present-day semi-arid conditions are associated with low amounts of excess Ne and elevated nitrate concentrations. In contrast to this, higher excess Ne values in groundwater of lower 14C DIC and nitrate contents indicate that the high quality groundwater end-member presumably is related to higher groundwater table fluctuations during wetter climatic conditions in the past. We attribute the decline in groundwater quality with respect to nitrate to a decreasing rate and temporal variability of groundwater recharge, and to concurrent changes in biogeochemical activities following a transition to a drier climate during the Holocene. Under such conditions, a much stronger decrease in groundwater recharge compared to the release of nitrate from soil organic matter may result in elevated nitrate concentrations in the vadose zone and groundwater. This implies

  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. Organochlorine pesticides in air and soil and estimated air-soil exchange in Punjab, Pakistan.

    PubMed

    Syed, Jabir Hussain; Malik, Riffat Naseem; Liu, Di; Xu, Yue; Wang, Yan; Li, Jun; Zhang, Gan; Jones, Kevin C

    2013-02-01

    This study provides the first systematic data on the distribution of organochlorine pesticides (OCPs) in the soils and atmosphere of the Punjab province, Pakistan. Atmospheric concentrations of OCPs were estimated by using the polyurethane foam passive air sampling (PUF-PAS) technique. DDTs (dichlorodiphenyltrichloroethane), HCHs (hexachlorocyclohexane) and chlordane were the dominant OCPs found in both soil and air samples. The average concentrations of DDTs, HCHs and chlordane were 350, 55 and 99 pg m(-3) in air and 40, 7.8 and 3.8 ng g(-1) in soils, respectively. Air-soil exchange of OCPs was estimated by calculating the fugacities in soil and air. Fugacity fraction (ff) values indicate that soils are acting as a secondary source to contaminate the atmosphere at certain sampling stations.

  1. 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.

  2. Groundwater decline, vegetation change, and surface soil stability in a semi-arid environment

    NASA Astrophysics Data System (ADS)

    Elmore, A. J.; Kaste, J. M.; Vest, K. R.

    2008-12-01

    Groundwater resources provide water to human populations within arid and semi-arid environments globally. In many regions, shallow groundwater has been overexploited, breaking a poorly understood link between above- and belowground processes in ecosystems dominated by groundwater dependent vegetation. Of particular importance are connections between groundwater and vegetation cover, soil resources, and surface soil stability. Although groundwater is thought to increase the risk of dust emissions from non- vegetated playas (a process that characterizes many of the dustiest places on earth) little is known regarding dust emissions from terrain covered by groundwater dependent vegetation. In a multi-year study of these effects in Owens Valley California, we are integrating field measurements of plant community composition, soil stability, and groundwater depth with remotely sensed measurements of vegetation cover with the goal of elucidating the processes behind ecosystem change in a groundwater dependent ecosystem. We have identified a strong non-linear response between vegetation cover from remote sensing and groundwater decline. This response includes a threshold in groundwater depth, which separates groundwater and precipitation driven vegetation dynamics. At sites where groundwater went below this threshold, a shift towards dominance by more deeply rooted shrub vegetation and unstable surface soils is qualitatively evident. Quantitative evidence from fallout radionuclide concentrations suggests that surface soil stability is lower in regions of groundwater decline, but there is significant within-site variability. Although fine sediments might be winnowed away, groundwater affected sites appear to be characterized by a reorganization of sediments from the inter-canopy zone, where more shallowly rooted grasses were once dominant, to the canopy zones surrounding deeper-rooted shrubs. Therefore, our preliminary finding is that the resource island desertification

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. Ground-water contamination at Wurtsmith Air Force Base, Michigan

    USGS Publications Warehouse

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

    1983-01-01

    A sand and gravel aquifer of glacial origin underlies Wurtsmith Air Force Base in northeastern lower Michigan. The aquifer overlies a thick clay layer at an average depth of 65 feet. The water table is about 10 feet below land surface in the western part of the Base and about 25 feet below land surface in the eastern part. A ground-water divide cuts diagonally across the Base from northwest to southeast. South of the divide, ground water flows to the Au Sable River; north of the divide, it flows to Van Etten Creek and Van Etten Lake. Mathematical models were used to aid in calculating rates of groundwater flow. Rates range from about 0.8 feet per day in the eastern part of the Base to about 0.3 feet per day in the western part. Models also were used as an aid in making decisions regarding purging of contaminated water from the aquifer. In 1977, trichloroethylene was detected in the Air Force Base water-supply system. It had leaked from a buried storage tank near Building 43 in the southeastern part of the Base and moved northeastward under the influence of the natural ground-water gradient and the pumping of Base water-supply wells. In the most highly contaminated part of the plume, concentrations are greater than 1,000 micrograms per liter. Current purge pumping is removing some of the trichloroethylene, and seems to have arrested its eastward movement. Pumping of additional purge wells could increase the rate of removal. Trichloroethylene has also been detected in ground water in the vicinity of the Base alert apron, where a plume from an unknown source extends northeastward off Base. A smaller, less well-defined area of contamination also occurs just north of the larger plume. Trichloroethylene, identified near the waste-treatment plant, seepage lagoons, and the northern landfill area, is related to activities and operations in these areas. Dichloroethylene and trichloroethylene occur in significant quantities westward of Building 43, upgradient from the major

  9. 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.

  10. [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.

  11. Soil Profile Sulfate in Irrigated Southern High Plains Cotton Fields and Ogallala Groundwater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil Profile Sulfate in Irrigated Southern High Plains Cotton Fields and Ogallala Groundwater Abstract: Sulfate (SO4) is one of the most important anions in soils and groundwater in semiarid regions, including West Texas. Crops’ sulfur (S) requirement is about 10 to 20 % of the nitrogen (N) require...

  12. Flooding forested groundwater recharge areas modifies microbial communities from top soil to groundwater table.

    PubMed

    Schütz, Kirsten; Nagel, Peter; Vetter, Walter; Kandeler, Ellen; Ruess, Liliane

    2009-01-01

    Subsurface microorganisms are crucial for contaminant degradation and maintenance of groundwater quality. This study investigates the microbial biomass and community composition [by phospholipid fatty acids (PLFAs)], as well as physical and chemical soil characteristics at woodland flooding sites of an artificial groundwater recharge system used for drinking water production. Vertical soil profiles to c. 4 m at two watered and one nonwatered site were analyzed. The microbial biomass was equal in watered and nonwatered sites, and considerable fractions (25-42%) were located in 40-340 cm depth. The microbial community structure differed significantly between watered and nonwatered sites, predominantly below 100 cm depth. Proportions of the bacterial PLFAs 16:1omega5, 16:1omega7, cy17:0 and 18:1omega9t, and the long-chained PLFAs 22:1omega9 and 24:1omega9 were more prominent at the watered sites, whereas branched, saturated PLFAs (iso/anteiso) dominated at the nonwatered site. PLFA community indices indicated stress response (trans/cis ratio), higher nutrient availability (unsaturation index) and changes in membrane fluidity (iso/anteiso ratio) due to flooding. In conclusion, water recharge processes led to nutrient input and altered environmental conditions, which resulted in a highly active and adapted microbial community residing in the vadose zone that effectively degraded organic compounds.

  13. 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.

  14. 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.

  15. Modeling the air-soil transport pathway of perfluorooctanoic acid in the mid-Ohio Valley using linked air dispersion and vadose zone models

    NASA Astrophysics Data System (ADS)

    Shin, Hyeong-Moo; Ryan, P. Barry; Vieira, Verónica M.; Bartell, Scott M.

    2012-05-01

    As part of an extensive modeling effort on the air-soil-groundwater transport pathway of perfluorooctanoic acid (PFOA), this study was designed to compare the performance of different air dispersion modeling systems (AERMOD vs. ISCST3), and different approaches to handling incomplete meteorological data using a data set with substantial soil measurements and a well characterized point source for air emissions. Two of the most commonly used EPA air dispersion models, AERMOD and ISCST3, were linked with the EPA vadose zone model PRZM-3. Predicted deposition rates from the air dispersion model were used as input values for the vadose zone model to estimate soil concentrations of PFOA at different depths. We applied 34 years of meteorological data including hourly surface measurements from Parkersburg Airport and 5 years of onsite wind direction and speed to the air dispersion models. We compared offsite measured soil concentrations to predictions made for the corresponding sampling depths, focusing on soil rather than air measurements because the offsite soil samples were less likely to be influenced by short-term variability in emission rates and meteorological conditions. PFOA concentrations in surface soil (0-30 cm depth) were under-predicted and those in subsurface soil (>30 cm depth) were over-predicted compared to observed concentrations by both linked air and vadose zone model. Overall, the simulated values from the linked modeling system were positively correlated with those observed in surface soil (Spearman's rho, Rsp = 0.59-0.70) and subsurface soil (Rsp = 0.46-0.48). This approach provides a useful modeling scheme for similar exposure and risk analyses where the air-soil-groundwater transport is a primary contamination pathway.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 40 CFR 280.65 - Investigations for soil and ground-water cleanup.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 28 2012-07-01 2012-07-01 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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).

  7. Conceptual Model for the Transport of Energetic Residues from Surface Soil to Groundwater by Range Activities

    DTIC Science & Technology

    2006-11-01

    ER D C/ CR R EL T R -0 6 - 1 8 Conceptual Model for the Transport of Energetic Residues from Surface Soil to Groundwater by Range...compounds potentially migrating to groundwater. The goals of the report are to 1 ) review and summarize previous work; 2) identify data gaps; 3) provide...Nomenclature.......................................................................................................................................viii 1

  8. 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...

  9. 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.

  10. 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.

  11. [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.

  12. 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.

  13. 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.

  14. 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

  15. 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)

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. U.S. Department of Energy/Environmental Management's Office of Groundwater and Soil Remediation Strategy

    SciTech Connect

    Magnuson, C.

    2007-07-01

    The vision for the Office of Groundwater and Soil Remediation is to focus and place high visibility on program achievements and broad-based remediation challenges and uncertainties facing the Office of Environmental Management. These include, but are not limited to, the development of contract performance measures; monitoring and controlling the cleanup investments for remediating groundwater and soil; finding and implementing interim and permanent cleanup remedies for technetium-99, strontium-90, chromium, uranium, and trichloroethylene; the development and use of sophisticated groundwater and fate and transport models; presenting the best science and engineering principles and practices for remediating groundwater and soil to environmental regulators and other key stakeholders; and ensuring that all source terms of contamination are fully identified and all sites are appropriately characterized. (authors)

  2. 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.

  3. 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...

  4. 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...

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Measurement and Modeling of Isotopomer Signatures of Nitrous Oxide from Soils and Groundwater

    NASA Astrophysics Data System (ADS)

    Well, R.; Flessa, H.; Jaradat, F.; Kurganova, I.; Lopes, V.

    2004-12-01

    18O and average 15N signatures of N2O have contributed to a better understanding of global N2O fluxes and of N2O source processes in aquatic and terrestric environments. Recently, new methods have been developed to analyze site-specific 15N abundance in order to further improve isotopic characterization of N2O. The aim of our study is to evaluate isotopomer signatures of N2O (i) as a tool to identify N2O production processes in soils and groundwater and (ii) to constrain the isotopic fingerprint of soil-derived N2O. A microcosm study was conducted with arable loess soil incubated at varying oxygen and moisture levels in order establish different levels of process rates. Analysis of soil extracts and emitted gases was conducted in order to quantify gross rates and N2O production of nitrification and denitrification, respectively, N2O reduction of denitrification and the isotopic fingerprint of emitted N2O. N2O production and reduction during denitrification and the isotopic fingerprint of groundwater N2O was investigated in sandy aquifers using in situ and laboratory techniques and simulations. 18O and site specific 15N-signatures of N2O produced in the soil and in the groundwater study were analyzed by isotope ratio mass spectrometry after cryo-focussing and GC-separation of the gas phase. The average delta 15N was related to soil moisture and denitrification in the soil microcosm study and to the reduction of groundwater dissolved nitrate by denitrification. The difference in delta 15N between the central and terminal N-position within the N2O molecule ("site preference") as well as delta 18O increased with soil moisture and with increasing nitrate reduction of groundwater nitrate. For the groundwater study, a simulated time course of isotopic signatures could be fitted to the measurements. The isotopic fingerprints of N2O derived from wet and dry soil and from the groundwater were clearly distinct. It is concluded that isotopomer signatures of N2O from soils and

  13. Shallow groundwater effect on land surface temperature and surface energy balance under bare soil conditions: modeling and description

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Appreciating when and how groundwater affects surface temperature and energy fluxes is important for utilizing remote sensing in groundwater studies and for integrating aquifers within land surface models. To explore the shallow groundwater effect, we numerically exposed two soil profiles – one havi...

  14. 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.

  15. 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

  16. Natural Attenuation of Hexavalent Chromium in Groundwater and Soils

    EPA Pesticide Factsheets

    Concerns about the impact of chromium on human health and the environment require an evaluation of the potential risk of chromium entering the groundwater flow system and being transported beyond compliance boundaries.

  17. 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.

  18. Experimental study of the effect of shallow groundwater table on soil thermal properties

    NASA Astrophysics Data System (ADS)

    Jiang, Jianmei; Zhao, Lin; Zeng, Yijian; Zhai, Zhe

    2016-03-01

    In plains areas with semi-arid climates, shallow groundwater is one of the important factors affecting soil thermal properties. In this study, soil temperature and water content were measured when groundwater tables reached 10 cm, 30 cm, and 60 cm depths (Experiment I, II, and III) by using sensors embedded at depths of 5 cm, 10 cm, 20 cm, and 30 cm for 5 days. Soil thermal properties were analyzed based on the experimental data using the simplified de Vries model. Results show that soil water content and temperature have fluctuations that coincide with the 24 h diurnal cycle, and the amplitude of these fluctuations decreased with the increase in groundwater table depth. The amplitude of soil water content at 5 cm depth decreased from 0.025 m3·m-3 in Experiment II to 0.01 m3·m-3 in Experiment III. Moreover, it should be noted that the soil temperature in Experiment III gradually went up with the lowest value increasing from 26.0°C to 28.8°C. By contrast, the trends were not evident in Experiments I and II. Results indicate that shallow groundwater has a "cooling" effect on soil in the capillary zone. In addition, calculated values of thermal conductivity and heat capacity declined with the increasing depth of the groundwater table, which is consistent with experimental results. The thermal conductivity was stable at a value of 2.3W·cm-1·K-1 in Experiment I. The average values of thermal conductivity at different soil depths in Experiment II were 1.82W·cm-1·K-1, 2.15W·cm-1·K-1, and 2.21W·cm-1·K-1, which were always higher than that in Experiment III.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  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. 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.

  7. 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.

  8. Characteristics and controls of variability in soil moisture and groundwater in a headwater catchment

    NASA Astrophysics Data System (ADS)

    McMillan, H. K.; Srinivasan, M. S.

    2015-04-01

    Hydrological processes, including runoff generation, depend on the distribution of water in a catchment, which varies in space and time. This paper presents experimental results from a headwater research catchment in New Zealand, where we made distributed measurements of streamflow, soil moisture and groundwater levels, sampling across a range of aspects, hillslope positions, distances from stream and depths. Our aim was to assess the controls, types and implications of spatial and temporal variability in soil moisture and groundwater tables. We found that temporal variability in soil moisture and water table is strongly controlled by the seasonal cycle in potential evapotranspiration, for both the mean and extremes of their distributions. Groundwater is a larger water storage component than soil moisture, and this general difference increases even more with increasing catchment wetness. The spatial standard deviation of both soil moisture and groundwater is larger in winter than in summer. It peaks during rainfall events due to partial saturation of the catchment, and also rises in spring as different locations dry out at different rates. The most important controls on spatial variability in storage are aspect and distance from the stream. South-facing and near-stream locations have higher water tables and showed soil moisture responses for more events. Typical hydrological models do not explicitly account for aspect, but our results suggest that it is an important factor in hillslope runoff generation. Co-measurement of soil moisture and water table level allowed us to identify relationships between the two. Locations where water tables peaked closer to the surface had consistently wetter soils and higher water tables. These wetter sites were the same across seasons. However, patterns of strong soil moisture responses to summer storms did not correspond to the wetter sites. Total catchment spatial variability is composed of multiple variability sources, and the

  9. 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...

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

    PubMed Central

    Khublarian, M G

    1989-01-01

    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. PMID:2559843

  11. 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.

  12. Use of arsenic contaminated irrigation water for lettuce cropping: effects on soil, groundwater, and vegetal.

    PubMed

    Beni, Claudio; Marconi, Simona; Boccia, Priscilla; Ciampa, Alessandra; Diana, Giampietro; Aromolo, Rita; Sturchio, Elena; Neri, Ulderico; Sequi, Paolo; Valentini, Massimiliano

    2011-10-01

    The present study investigated the effects of using arsenic (As) contaminated irrigation water in Lactuca sativa L. cropping. Two different arsenic concentrations, i.e., 25 and 85 μg L(-1) and two different soils, i.e., sandy and clay loam, were taken into account. We determined the arsenic mobility in the different soil fractions, its amount in groundwater, and the phytotoxicity and genotoxicity. Nuclear magnetic resonance (NMR) and inductively coupled plasma (ICP) were used to assess the lettuce metabolic profile changes and the arsenic uptake by the plant, respectively, as a function of the various conditions studied, i.e., As content and type of soil. Data indicated that at both concentrations in sandy soil, arsenic is in part quickly leached and thus present in groundwater and in part absorbed by the vegetable, being therefore readily available for assimilation by consumption. NMR results reported a large modification of the metabolic pattern, which was depending on the pollutant amount. In clay loam soil, the groundwater had a low As content with respect to sandy soil, and NMR and ICP performed on the lettuce did not reveal severe changes related to As, most likely because the metalloid is bound to the colloidal fraction.

  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. 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...

  15. Chemical contaminant reactions and assessment of soil cleanup levels for protection of groundwater

    NASA Astrophysics Data System (ADS)

    Kargbo, D. M.

    1994-03-01

    About 70 percent of hazardous waste sites listed in the National Priority List (NPL) have some groundwater contamination that may require remediation. Such remediation is inadequate if the unsaturated soils above will continue to act as a source of groundwater contamination. Consequently, for most of these sites, it becomes necessary to determine what the cleanup levels for contaminants in soils should be so that subsequent contribution of contaminants from these soils to groundwater would not exceed groundwater protection levels. Representation of the dynamics of interactions between contaminants and soils is very complex, requiring among others, a thorough understanding of the chemical processes that influence the behavior of the contaminant once it enters the subsurface. Because of such complexities, environmental professionals frequently utilize methods with very simple assumptions that tend to err on the conservative side. While the public may feel protected, the needless spending of dollars could be avoided if attempts are made to incorporate, where possible, such complexities in the modeling efforts so that the system is represented as accurately as possible.

  16. Estimating groundwater evapotranspiration from irrigated cropland incorporating root zone soil texture and moisture dynamics

    NASA Astrophysics Data System (ADS)

    Wang, Xingwang; Huo, Zailin; Feng, Shaoyuan; Guo, Ping; Guan, Huade

    2016-12-01

    Estimating evapotranspiration from groundwater (ETg) is of importance to understanding water cycle and agricultural water management. Traditional ETg estimation was developed for regional steady condition and is difficult to be used for cropland where ETg changes with crop growth and irrigation schemes. In the present study, a new method estimating daily ETg during the crop growing season was developed. In this model, the effects of crop growth stage, climate condition, groundwater depth and soil moisture are considered. The method was tested with controlled lysimeter experiments of winter wheat including five controlled water table depths and four soil profiles of different textures. The simulated ETg is in good agreement with the measured data for four soil profiles and different depths to groundwater table. Coefficient of determination (R2) and coefficient of efficiency (NSE) are mostly larger than 0.85 and 0.70, respectively. This result suggests that the new method incorporating both soil texture and moisture dynamics can be used to estimate average daily groundwater evapotranspiration in cropland and contribute to quantifying the field water cycle.

  17. 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 ...

  18. 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...

  19. 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 ...

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Evaluation of groundwater and soil pollution in a landfill area using electrical resistivity imaging survey.

    PubMed

    Ahmed, A M; Sulaiman, W N

    2001-11-01

    Landfills are sources of groundwater and soil pollution due to the production of leachate and its migration through refuse. This study was conducted in order to determine the extent of groundwater and soil pollution within and around the landfill of Seri Petaling located in the State of Selangor, Malaysia. The condition of nearby surface water was also determined. An electrical resistivity imaging survey was used to investigate the leachate production within the landfill. Groundwater geochemistry was carried out and chemical analysis of water samples was conducted upstream and downstream of the landfill. Surface water was also analyzed in order to determine its quality. Soil chemical analysis was performed on soil samples taken from different locations within and around the landfill in the vadose zone (unsaturated zone) and below the water table (in the soil saturated zone). The resistivity image along line L-L1 indicated the presence of large zones of decomposed waste bodies saturated with highly conducting leachate. Analysis of trace elements indicated their presence in very low concentrations and did not reflect any sign of heavy metal pollution of ground and surface water or of soil. Major ions represented by Na, K, and Cl were found in anomalous concentrations in the groundwater of the downstream bore hole, where they are 99.1%, 99.2%, and 99.4%, respectively, higher compared to the upstream bore hole. Electrical conductivity (EC) was also found in anomalous concentration downstream. Ca and Mg ions represent the water hardness (which is comparatively high downstream). There is a general trend of pollution towards the downstream area. Sulfates (SO4) and nitrates (NO3) are found in the area in low concentrations, even below the WHO standards for drinking water, but are significantly higher in the surface water compared to the groundwater. Phosphate (PO4) and nitrite (NO2), although present in low levels, are significantly higher at the downstream. There is no

  5. Levels and distributions of organochlorine pesticides in the soil-groundwater system of vegetable planting area in Tianjin City, Northern China.

    PubMed

    Pan, Hong-Wei; Lei, Hong-Jun; He, Xiao-Song; Xi, Bei-Dou; Han, Yu-Ping; Xu, Qi-Gong

    2017-04-01

    To study the influence of long-term pesticide application on the distribution of organochlorine pesticides (OCPs) in the soil-groundwater system, 19 soil samples and 19 groundwater samples were collected from agricultural area with long-term pesticide application history in Northern China. Results showed that the composition of OCPs changed significantly from soil to groundwater. For example, ∑DDT, ∑HCH, and ∑heptachlor had high levels in the soil and low levels in the groundwater; in contrast, endrin had low level in the soil and high level in the groundwater. Further study showed that OCP distribution in the soil was significantly influenced by its residue time, soil organic carbon level, and small soil particle contents (i.d. <0.0002 mm). Correlation analysis also indicates that the distribution of OCPs in the groundwater was closely related to the levels of OCPs in the soil layer, which may act as a pollution source.

  6. 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.

  7. State Summary of Soil and Groundwater Cleanup Standards for Hydrocarbons

    DTIC Science & Technology

    2007-11-02

    821096-01 November 15, 1993 19970425 057 !DISTfRIBUTI STýA-TEM,_ Approved for public release; Distribution Unlbfited Product - Paranmeter/ Lab Test...Env-mmenal Mantagemen, 20-270-5613 Product Parameter/ Lab Test Protocol Detection Notification Action Clean-up Level Constituent & Number Level Level...Envi-mnentai Managament, 205-270-.5613 Su m r of Alsk Clanu Sadr s fo Hyrcro Cotmiae Groundwater Product- - Parameter/ Lab Test Protocol ’Detection

  8. Reductive immobilization of pertechnetate in soil and groundwater using synthetic pyrite nanoparticles.

    PubMed

    Huo, Lijuan; Xie, Wenbo; Qian, Tianwei; Guan, Xiaohong; Zhao, Dongye

    2017-05-01

    Radioactive technetium ((99)Tc) is of intense concern because of its toxicity and high mobility in the environment. Reduction of Tc(VII) to Tc(IV) decreases the mobility and availability of technetium in soil and groundwater. In this study, pyrite nanoparticles (FeS2) were synthesized, characterized and tested for immobilizing/removing (99)Tc(VII) in soil and groundwater through batch and column experiments. Influences of particle dosage, dissolved organic matter (DOM), and pH on the reductive immobilization kinetics were examined. At a dosage of 0.28 g/L as Fe, the pyrite nanoparticles were able to rapidly and completely remove 4.88 × 10(-7) M of Tc(VII) by converting it to insoluble Tc(IV), with a retarded first-order rate constant of 0.30 h(-1). The presence of high concentrations of DOM only moderately inhibited the reduction effectiveness, and acidic pH was more favorable for Tc(VII) reduction. Column experiments showed that embedding a 0.8 cm pyrite layer of the material in a soil bed, simulating a permeable reactive barrier, was able to retard technetium transport 710 times more than a model sandy soil. The results demonstrated that the pyrite particles may serve as a long-lasting reactive material to remediate Tc-contaminated soil, groundwater and solid wastes.

  9. 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.

  10. Isotopic mixing model for quantifying contributions of soil water and groundwater in subsurface ('tile') drainage

    NASA Astrophysics Data System (ADS)

    Kennedy, C. D.; Gall, H.; Jafvert, C. T.; Bowen, G. J.

    2010-12-01

    Subsurface (‘tile’) drainage, consisting of buried grids of perforated pipe, has provided a means of converting millions of acres of poorly drained soils in the Midwestern U.S. into fertile cropland. However, by altering pathways and rates of soil water and groundwater movement through agricultural lands, this practice may accelerate the loss of nitrate and other agrochemicals. To better understand the hydrological controls on nitrogen dynamics in artificially drained agricultural watersheds, a field sampling program has been established at the Animal Science Research and Education Center (ASREC) at Purdue University (West Lafayette, Indiana) to (1) measure precipitation amount, tile flow, and water-table elevation, and (2) collect water samples for analysis of nitrate, major ions, and oxygen isotope ratios in precipitation, tile drainage, shallow (1 m) and deep (3 m) groundwater, and soil water during storm events. Preliminary physical, chemical, and isotopic data collected at the ASREC show a coincident timing of peak storm ‘event water’ and peak nitrate flux in tile drainage, suggesting significant routing of infiltrating event water. In this work, we aim to refine our understanding of tile drainage at the ASREC by developing a mixing model for partitioning contributions of soil water and groundwater in tile drainage during several storm runoff events ranging in precipitation intensity and coinciding with varying antecedent soil moisture conditions. The results of our model will describe tile drainage in terms of its hydrological components, soil water and groundwater, which in turn will provide a means of incorporating the effects of tile drainage in surface/subsurface hydrological transport models.

  11. Coupling approaches for groundwater-soil-atmosphere interaction in a pre-Alpine environment

    NASA Astrophysics Data System (ADS)

    Fersch, B.; Wagner, S.; Rummler, T.; Gochis, D. J.; Kunstmann, H.

    2012-12-01

    The interaction between groundwater and soil-moisture and its implications for the exchange of water and energy with the atmosphere has recently gained increasing attention, especially when groundwater levels are shallow. Most of the current land-surface-models (LSMs) like the Noah-LSM of the WRF-ARW model neglect processes of interaction among groundwater, soil-moisture and atmosphere. Therefore, the complex, nonlinear exchange processes and the feedback between these compartments cannot be sufficiently captured. Historically, hydrological and atmospheric (including LSM) models were developed by separate research communities. Their unification should enable the analysis of complex cross-compartment interaction among groundwater, soil-moisture, and atmosphere, capturing also the lateral water transport within the saturated zone. However, it is of crucial importance how the interface between saturated zone (groundwater model) and the soil layers of the LSM is specified. We present a comparison of different approaches for a two-way coupled representation of the water transport between saturated zone and soil moisture in a groundwater/Noah-LSM type modeling system that enhances the NCAR Distributed Hydrological Modeling System (NDHMS). The applied approaches range from straightforward methods (e.g. assuming a linear gradient in the deep unsaturated zone) to more sophisticated ones assuming quasi-equilibrium conditions (modified Zeng and Decker, 2008) or the Darcy equation-based flux parameterization of Bogaart et al. (2008). The sensitivity and impact of the different coupling approaches is tested and evaluated in a single-column study using extensive observations from the TERENO pre-Alpine observatory (http://tereno.net). Furthermore, the sensitivity of the coupling is examined in a 2D application of the NDHMS model for the Ammer/Rott catchment in Southern Germany. Bogaart P., Teuling A., Troch P. (2008): A state-dependent parametrization of saturated

  12. Quantifying effects of soil heterogeneity on groundwater pollution at four sites in USA.

    PubMed

    Vuurens, Saskia; Stagnitti, Frank; de Rooij, Gerrit; Boll, Jan; Li, Ling; LeBlanc, Marc; Ierodiaconou, Daniel; Versace, Vince; Salzman, Scott

    2005-05-01

    Four sites located in the north-eastern region of the United States of America have been chosen to investigate the impacts of soil heterogeneity in the transport of solutes (bromide and chloride) through the vadose zone (the zone in the soil that lies below the root zone and above the permanent saturated groundwater). A recently proposed mathematical model based on the cumulative beta distribution has been deployed to compare and contrast the regions' heterogeneity from multiple sample percolation experiments. Significant differences in patterns of solute leaching were observed even over a small spatial scale, indicating that traditional sampling methods for solute transport, for example the gravity pan or suction lysimeters, or more recent inventions such as the multiple sample percolation systems may not be effective in estimating solute fluxes in soils when a significant degree of soil heterogeneity is present. Consequently, ignoring soil heterogeneity in solute transport studies will likely result in under- or overprediction of leached fluxes and potentially lead to serious pollution of soils and/or groundwater. The cumulative beta distribution technique is found to be a versatile and simple technique of gaining valuable information regarding soil heterogeneity effects on solute transport. It is also an excellent tool for guiding future decisions of experimental designs particularly in regard to the number of samples within one site and the number of sampling locations between sites required to obtain a representative estimate of field solute or drainage flux.

  13. 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.

  14. Characterization of the shallow groundwater system in an area with thin soils and sinkholes

    NASA Astrophysics Data System (ADS)

    Wiersma, James H.; Stieglitz, Ronald D.; Cecil, Dewayne L.; Metzler, Glenn M.

    1986-03-01

    Door County, Wisconsin, is a region of karst topography underlain by Silurian dolomite bedrock. Numerous sinkholes intercept much of the surface runoff and act as sites for direct groundwater recharge. The clay-rich and impermeable Upper Ordovician Maquoketa formation separates the dolomite aquifer from the deeper aquifers and appears to be a factor in groundwater circulation and karst formation Thin glacial drift and Quaternary materials overlie the dolomite and are hydrologically connected with it The interactions of surface and groundwater, and the role of solution features in water interchange were studied in a small drainage basin. This basin contains several large sinkholes and a nearby spring complex Mapping identified many additional sinks and swallets in surface drainage routes Water flowing into two sinks was traced and found to have a residence time of several hours. Water flowing into sinkholes and from the spring was sampled to identify the quality and seasonal trends in composition of the shallow groundwater Water quality parameters monitored include magnesium, sodium, potassium, chloride, phosphorous, nitrate and ammonia, nitrogen, alkalinity, pH, turbidity, and specific conductance. Nitrate levels were found to increase 5 to 6 times during periods when there was zero input through sinkhole recharge sites. Nitrate levels approached the 10 mg/l NO3 --N limit set by the U.S. Public Health Service for drinking water In this basin sandy soils are most susceptible to sink development, whereas clay-rich soils have a lesser number of sinks. It appears, however, that a network of bedrock solution features exists under all soils The loss of soil into sinkholes has impacted groundwater quality and reduced agricultural productivity through a reduction in tillable acreage and water retention capacity.

  15. PIMS:Remediation of Soil and Groundwater Contaminated With Metals

    DTIC Science & Technology

    2006-06-01

    covering the amended soils with a layer of uncontaminated surface soil, and seeding with native grasses and wildflowers . Shallow lysimeter monitoring... wildflowers and grasses. Shallow lysimeter wells were installed at three positions around the site to collect leachate leaving the treatment zone...Priority Pollutants Laboratory, Inc. (APPL) in Fresno, California . This page left blank intentionally. 17 4.0 PERFORMANCE ASSESSMENT 4.1

  16. Identifying anthropogenic anomalies in air, surface and groundwater temperatures in Germany.

    PubMed

    Benz, Susanne A; Bayer, Peter; Blum, Philipp

    2017-04-15

    Human activity directly influences ambient air, surface and groundwater temperatures. The most prominent phenomenon is the urban heat island effect, which has been investigated particularly in large and densely populated cities. This study explores the anthropogenic impact on the thermal regime not only in selected urban areas, but on a countrywide scale for mean annual temperature datasets in Germany in three different compartments: measured surface air temperature, measured groundwater temperature, and satellite-derived land surface temperature. Taking nighttime lights as an indicator of rural areas, the anthropogenic heat intensity is introduced. It is applicable to each data set and provides the difference between measured local temperature and median rural background temperature. This concept is analogous to the well-established urban heat island intensity, but applicable to each measurement point or pixel of a large, even global, study area. For all three analyzed temperature datasets, anthropogenic heat intensity grows with increasing nighttime lights and declines with increasing vegetation, whereas population density has only minor effects. While surface anthropogenic heat intensity cannot be linked to specific land cover types in the studied resolution (1km×1km) and classification system, both air and groundwater show increased heat intensities for artificial surfaces. Overall, groundwater temperature appears most vulnerable to human activity, albeit the different compartments are partially influenced through unrelated processes; unlike land surface temperature and surface air temperature, groundwater temperatures are elevated in cultivated areas as well. At the surface of Germany, the highest anthropogenic heat intensity with 4.5K is found at an open-pit lignite mine near Jülich, followed by three large cities (Munich, Düsseldorf and Nuremberg) with annual mean anthropogenic heat intensities >4K. Overall, surface anthropogenic heat intensities >0K and

  17. Water dynamics and groundwater contributions in a young mountain soil under different meteorological conditions

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Groundwater contribution to the soil-water content and to the evapotranspiration is a major uncertainty to assess the water balance. Particularly in mountain environments, where the soil and the depth of the water table are shallow, both percolation and water rise from the water table can happen. Aiming at better understanding these processes at the local scale, a micrometeorological station, equipped with both traditional sensors, an eddy covariance (EC) apparatus with a 20Hz sonic anemometer and infrared CO2 and H2O gas analyser, and four multiplexed TDR probes, was installed at Cividate Camuno (Oglio river basin, Central Italian Alps, Italy, 274ma.s.l.), in a mountain environment with complex topography and Alpine sublitoranean climate. The young, anthropised, soil upper layers are about 40cm deep and mainly covered by alfalfa (Medicago sativa), wild carrot (Daucus carota) and yarrow (Achillea millefolium). Field and laboratory tests were performed to characterise the soil hydraulic properties. Particularly the soil-water retention relationships were measured by means of a low- and a high-pressure Richards' apparatus, and the hydraulic conductivity at saturation of each soil layer was estimated by 2-dimensional, axis-symmetrical, inverse modelling of field infiltration tests from single ring infiltrometer. The measurements were performed during Summer 2012 and Summer 2013. The groundwater exchange was numerically estimated both in wet (Summer 2012) and in dry meteorlogical conditions (Summer 2013). Evapotranspiration was assessed by means of Penman-Monteith method, which was found to be in the range between EC-estimated fluxes and an indirect estimate based on the Bowen ratio correction for Summer 2012. The two seasons are meteorologically very different and it results also in the soil-water regime. During Summer 2012, the weather was relatively wet, the soil did not reach very small water contents, so that precipitation was able to percolate towards the

  18. 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

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  20. PAHs in soils and estimated air-soil exchange in the Pearl River Delta, South China.

    PubMed

    Liu, Guoqing; Yu, Lili; Li, Jun; Liu, Xiang; Zhang, Gan

    2011-02-01

    In this study, 74 soil samples collected from the Pearl River Delta were analyzed for polycyclic aromatic hydrocarbons (PAHs). The PAH mixture in the soils is mainly of low molecular weight compounds, with naphthalene (21.4%) and phenanthrene (21.8%) being dominant. Soil PAH levels from the Pearl River Delta are relatively low (28-711 ng/g, averaged 192 ng/g) compared to those from urban soils in temperate regions. The mean concentration of ΣPAHs generally decrease with increasing distance from the city center, with ΣPAHs of paddy soils>crop soil>natural soil. PAHs in the air were measured during a year-round sampling campaign using semipermeable membrane devices, and the transfer of chemicals between the soil and air compartments were estimated. Soil-air fugacity quotient calculations showed a highly uncertain equilibrium position of PAHs, with net volatilization of naphthalene and fluorene, whereas net deposition of phenanthrene, fluoranthene, and pyrene, indicating a capacity for the air to supply the soil with more substances.

  1. Phytoremediation of Groundwater at Air Force Plant 4, Carswell, Texas

    DTIC Science & Technology

    2003-09-01

    swings in soil water potential through transpiration and by the continual addition of water-retentive organic matter. In essence , the 6 plant-microbe...ability of trees to act as pumps was noted in the late 19th century when Eucalyptus trees were planted in Italy and Algeria to dry up marshes. The...development of short rotation crops such as cottonwoods, hybrid poplar, willow, eucalyptus , or other energy crops, requires consideration of operational

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Long-Term Groundwater Monitoring Optimization, Clare Water Supply Superfund Site, Permeable Reactive Barrier and Soil Remedy Areas, Clare, Michigan

    EPA Pesticide Factsheets

    This report contains a review of the long-term groundwater monitoring network for the Permeable Reactive Barrier (PRB) and Soil Remedy Areas at the Clare Water Supply Superfund Site in Clare, Michigan.

  7. 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

  8. 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...

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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...

  14. Soil temperature prediction from air temperature for alluvial soils in lower Indo-Gangetic plain

    NASA Astrophysics Data System (ADS)

    Barman, D.; Kundu, D. K.; Pal, Soumen; Pal, Susanto; Chakraborty, A. K.; Jha, A. K.; Mazumdar, S. P.; Saha, R.; Bhattacharyya, P.

    2017-01-01

    Soil temperature is an important factor in biogeochemical processes. On-site monitoring of soil temperature is limited in spatiotemporal scale as compared to air temperature data inventories due to various management difficulties. Therefore, empirical models were developed by taking 30-year long-term (1985-2014) air and soil temperature data for prediction of soil temperatures at three depths (5, 15, 30 cm) in morning (0636 Indian standard time) and afternoon (1336 Indian standard time) for alluvial soils in lower Indo-Gangetic plain. At 5 cm depth, power and exponential regression models were best fitted for daily data in morning and afternoon, respectively, but it was reverse at 15 cm. However, at 30 cm, exponential models were best fitted for both the times. Regression analysis revealed that in morning for all three depths and in afternoon for 30 cm depth, soil temperatures (daily, weekly, and monthly) could be predicted more efficiently with the help of corresponding mean air temperature than that of maximum and minimum. However, in afternoon, prediction of soil temperature at 5 and 15 cm depths were more precised for all the time intervals when maximum air temperature was used, except for weekly soil temperature at 15 cm, where the use of mean air temperature gave better prediction.

  15. 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

  16. 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.

  17. 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...

  18. Nitrate retention as it affects groundwater pollution in Mid-Atlantic soils. Completion report

    SciTech Connect

    Sparks, D.L.

    1987-09-14

    Nitrate retention (NO/sub 3/) as it affects groundwater pollution was investigated on nine major Mid-Atlantic soil types. Objectives of the study were to determine the magnitude and rate of NO/sub 3/ retention and the effect of anion competition on NO/sub 3/ retention. The soils had a wide range in organic matter, clay and oxide content. Charge properties including anion exchange capacity (AEC) and point of zero salt effect (PZSE) were determined. The PZSE values were low indicating little anion-adsorption capacity, while AEC values often significant and increased with profile depth as oxide and clay contents increased.

  19. 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.

  20. 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

  1. 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.

  2. [Phenols pollutants in soil and shallow groundwater of a retired refinery site].

    PubMed

    Pei, Fang; Luo, Ze-Jiao; Peng, Jin-Jin; Qi, Shi-Hua

    2012-12-01

    To study the distribution of phenol compounds in a retired refinery site, 21 soil sampling sites and 8 shallow groundwater wells were investigated. The results showed, shallow unconfined groundwater of the site was in a serious pollution situation and the phenols concentration was much higher than quality standard for ground water. Confined water sample was slightly contaminated by phenols and the total quality was good. Approximately half of the area was heavily polluted by phenol compounds. According to the retired refinery layout, the phenols pollution distribution in shallow groundwater and soil exhibited the regional similarity. The highly contaminated area was production workshop, oil tank and plant storage. Horizontal diffusion of pollutants was not serious. Vertical diffusion of pollutants was different, and a site with pollutant diffusion was deeper than ten meters. The 2-chlorophenol, 2-nitrophenol, 2,4-xylenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol, 2,4-dinitrophenol and 2-methyl-4,6-dinitrophenol in typical soils were analyzed by GC/MS. It showed that concentrations of seven phenol compounds were 0.01-232.96 mg x kg(-1), and the concentrations of 2,4-dinitrophenol and 2-methyl-4,6-dinitrophenol were high.

  3. Organochlorine pesticides in soils and air of southern Mexico: Chemical profiles and potential for soil emissions

    NASA Astrophysics Data System (ADS)

    Wong, Fiona; Alegria, Henry A.; Jantunen, Liisa M.; Bidleman, Terry F.; Salvador-Figueroa, Miguel; Gold-Bouchot, Gerardo; Ceja-Moreno, Victor; Waliszewski, Stefan M.; Infanzon, Raul

    The extent of organochlorine pesticides (OCs) contamination in southern Mexico was investigated in this study. Biweekly air samplings were carried out in two sites in the state of Chiapas (during 2002-2003), and one in each state of Veracruz and Tabasco (during 2003-2004). Corresponding to the air sampling locations, soil samples were also collected to gauge the soil-air exchange of OCs in the region. ∑DDTs in soils ranged from 0.057 to 360 ng g -1 whereas those in air ranged from 240 to 2400 pg m -3. DDT and metabolite DDE were expressed as fractional values, FDDTe = p, p'-DDT/( p, p'-DDT + p, p'-DDE) and FDDTo = p,p'-DDT/( p,p'-DDT + o,p'-DDT). FDDTe in soils ranged from 0.30 to 0.69 while those in air ranged from 0.45 to 0.84. FDDTe in air at a farm in Chiapas (0.84) was closer to that of technical DDT (0.95) which is suggestive of fresh DDT input. Enantiomer fractions (EF) of o,p'-DDT in air were racemic at all locations (0.500-0.504). However, nonracemic o,p'-DDT was seen in the soils (EFs = 0.456-0.647). Fugacities of OCs in soil ( fs) and air ( fa) were calculated, and the fugacity fraction, ff = fs/( fs + fa) of DDTs ranged from 0.013 to 0.97 which indicated a mix of net deposition ( ff < 0.5) and volatilization ( ff > 0.5) from soil among the sites. It is suggested that DDTs in Mexico air are due to a combination of ongoing regional usage and re-emission of old DDT residues from soils. Total toxaphene in soils ranged from 0.066 to 69 ng g -1 while levels in air ranged from 6.2 to 230 pg m -3. Chromatographic profiles of toxaphenes in both air and soil showed depletion of Parlar congeners 39 and 42. Fugacity fractions of toxaphene were within the equilibrium range or above the upper equilibrium threshold boundary. These findings suggested that soil emission of old residues is the main source of toxaphenes to the atmosphere. Results from this study provide baseline data for establishing a long-term OC monitoring program in Mexico.

  4. 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

  5. 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

  6. Simulating an exclusion zone for vapour intrusion of TCE from groundwater into indoor air.

    PubMed

    Wang, Xiaomin; Unger, Andre J A; Parker, Beth L

    2012-10-01

    This paper is an extension of the work by Yu et al. (2009) to examine exposure pathways of volatile organic compounds (VOCs) originating from a NAPL source zone located below the water table, and their potential impact on multiple residential dwellings down-gradient of the source zone. The three-dimensional problem geometry is based on the Rivett (1995) field experiment in the Borden aquifer, and contains houses located both above and adjacent to the groundwater plume in order to define an exclusion zone. Simulation results using the numerical model CompFlow Bio indicate that houses which are laterally offset from the groundwater plume are less affected by vapour intrusion than those located directly above the plume due to limited transverse horizontal flux of TCE within the groundwater plume, in agreement with the ASTM (2008) guidance. Uncertainty in the simulated indoor air concentration is sensitive to heterogeneity in the permeability structure of a stratigraphically continuous aquifer, with uncertainty defined as the probability of simulated indoor air concentrations exceeding the NYSDOH (2005) regulatory limit. Within this uncertainty framework, this work shows that the Johnson and Ettinger (1991), ASTM (2008) and CompFlow Bio models all delineate an identical exclusion zone at a 99.9% confidence interval of indoor air concentrations based on the probability of exceedence.

  7. Simulating an exclusion zone for vapour intrusion of TCE from groundwater into indoor air

    NASA Astrophysics Data System (ADS)

    Wang, Xiaomin; Unger, Andre J. A.; Parker, Beth L.

    2012-10-01

    This paper is an extension of the work by Yu et al. (2009) to examine exposure pathways of volatile organic compounds (VOCs) originating from a NAPL source zone located below the water table, and their potential impact on multiple residential dwellings down-gradient of the source zone. The three-dimensional problem geometry is based on the Rivett (1995) field experiment in the Borden aquifer, and contains houses located both above and adjacent to the groundwater plume in order to define an exclusion zone. Simulation results using the numerical model CompFlow Bio indicate that houses which are laterally offset from the groundwater plume are less affected by vapour intrusion than those located directly above the plume due to limited transverse horizontal flux of TCE within the groundwater plume, in agreement with the ASTM (2008) guidance. Uncertainty in the simulated indoor air concentration is sensitive to heterogeneity in the permeability structure of a stratigraphically continuous aquifer, with uncertainty defined as the probability of simulated indoor air concentrations exceeding the NYSDOH (2005) regulatory limit. Within this uncertainty framework, this work shows that the Johnson and Ettinger (1991), ASTM (2008) and CompFlow Bio models all delineate an identical exclusion zone at a 99.9% confidence interval of indoor air concentrations based on the probability of exceedence.

  8. 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.

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

    ScienceCinema

    Moore, Robert; Szecsody, Jim; Thompson, Mike

    2016-07-12

    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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. Control of aromatic waste air streams by soil bioreactors

    SciTech Connect

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

    1991-11-01

    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 from Ada, Oklahoma, and Dougherty Sand from Stratford, Oklahoma. Soil columns were used to examine the effects of soil type, air flow rate and inlet vapor concentrations. Adjustment of the hydrocarbon loading rate produced removals which corresponded to first-order removal kinetics. Estimated residence times of 10 to 20 minutes produced removals of the individual inlet BTEX compounds which ranged from 8 to 39%. Increasing the residence time produced increased removals corresponding to first-order removal rates. Further increases in the residence time revealed transport limitations which restricted additional removals. Soil which had moisture less than 50% of saturation displayed preferential utilization of benzene followed in order by ethylbenzene, toluene, and o-xylene.

  17. 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

  18. 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...

  19. Groundwater-Driven Chemical Weathering of Young Granitic Soils in the San Joaquin Valley, California

    NASA Astrophysics Data System (ADS)

    Balan, S. A.; Amundson, R.

    2008-12-01

    Sierran rivers that drain into the eastern San Joaquin Valley have deposited large alluvial fans of granitic glacial outwash of latest Pleistocene age. From the well-drained apex, to the poorly drained distal margins of these fans, soils change from slightly acidic and relatively salt free to highly alkaline and saline due to differential interactions with shallow aquifers. Here, we examined three soils representing the gradation from salt free to highly saline (Hanford, Hesperia and Fresno), focusing on major and minor element chemistry. The applicability of a mass-balance approach for quantifying net chemical gains and losses was tested. The Hanford soil has a relatively uncomplicated weathering history and elemental depth profiles are governed by downward aqueous transport and biological cycling. The elemental depth profiles of the Hesperia and Fresno soils are determined by the combination of downward transport by rainfall and upward transport by groundwater through capillary action. The Hesperia soil, which is in the intermediate elevation position, has only minor evidence of gleying but has experienced considerable accumulations of both Ca and Na carbonates. In contrast, the Fresno soil has abundant redoximorphic features and significant accumulations of secondary phyllosilicates (and zeolite) and secondary opal due to weathering processes enhanced by the longer duration of water in the soil and the extremely high pH. Despite the chemical heterogeneity of the alluvium from which the soil formed, mass balance analyses provided useful information. Bulk average transport functions combined with depth trends of immobile elements like Zr and the rare earths revealed that the effects of the groundwater on the soils consist of net additions, mostly of Ca, Sr and Mg carbonates and phosphates. The mass balance also suggests that the processes that formed the secondary clay and opal were largely conservative, and only a small loss of Si is likely. The soils reveal the

  20. 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).

  1. In-situ bioremediation of groundwater using a horizontal injection well in clay soil, Madisonville, TN

    SciTech Connect

    Miller, M.B.; Clark, D.A.; Handler, M.; Zhing-Ming Huang

    1996-09-01

    Tennessee`s first horizontal groundwater remediation well was installed at Madisonville located in the eastern Valley and Ridge Province. The open-ended well, drilled through clay soil, is constructed of 280 feet HDPE pipe, 2 inches in diameter, with a screen length of 100 feet at 18 feet below ground surface. The purpose of the well is to remediate gasoline contaminated groundwater that resulted from a leaking underground storage tank (UST) system. The groundwater benzene and TPH plumes covered an area of one-half acre and extended beneath a rural grocery store. Remediation is achieved by injecting aerated water, nutrients and microbes to reduce contaminant levels to drinking water standards. MODFLOW was utilized to computer-model the development of the groundwater mound that would result from injection. It was calculated that one horizontal injection well would equal the efficiency of 80 vertical injection wells. Benzene and TPH masses have been reduced by 92% and 95% respectively. BIOTRANS calculated the bio-decay rate to determine remediation time. This system will reduce project life and eliminate additional costs associated with: operations and maintenance (versus vertical pump and treat), water disposal, emissions controls, well installations, and site disturbance. A {open_quotes}Minimum Economic Plume Size{close_quotes}, the minimum plume volume required to support a horizontal system has been developed. Although costs per foot are greater for horizontal drilling than vertical drilling, project costs savings are realized later in the project.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Amoco-US Environmental Protection Agency, pollution prevention project, Yorktown, Virginia: Groundwater and soil data

    SciTech Connect

    Cozens-Roberts, C.; Kremesec, V.J.; Hockman, E.L.

    1991-03-01

    At the Amoco Company refinery in Yorktown, Virginia, potential sources and sinks of groundwater contamination were evaluated to determine the affects of the plant on the subsurface. Subsurface characterization of the refinery included an extensive subsurface sampling program that included 39 soil borings, 181 monitoring wells, and 23 surface water sampling points. Groundwater flow was modeled using FTWORK, a modification of MODFLOW. Results showed that, due to above ground process piping, contamination at the Yorktown refinery was significantly less than that observed at other refineries. Free-phase hydrocarbons were only detected in one monitoring well. Metals contamination was limited to monitoring wells associated with historic waste management activities at the east end of the refinery. Contamination was detected in monitoring wells located adjacent to process units but affects were limited due to the process sewer acting as a collection point.

  7. 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.

  8. 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.

  9. 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.

  10. Estimation of Soil Moisture Content Using Air-Launched GPR Techniques in Variable Soil Conditions

    NASA Astrophysics Data System (ADS)

    Hardel, B.; Kelly, B.

    2008-12-01

    Air-launched Ground Penetrating Radar (GPR) techniques have most frequently been used for infrastructure characterization, but these techniques show promise for soil moisture estimation in the near subsurface. Air- launched GPR data can be acquired very quickly, and data processing can be easily automated, so these techniques have potential for efficient estimation of water content in the shallow subsurface over large areas. In this experiment, we investigate the efficacy of air-launched GPR techniques for estimating soil water content under saturated and dry conditions in both sandy and organic-rich soils. Data were also acquired to investigate the depth of penetration of air-launched data in these soils using multiple GPR frequencies. The experiment was performed in a large tank under controlled climatic conditions. Initially, the tank was filled with wet sand to a depth of 24-cm, and GPR data were acquired over the sand using 250-, 500-, and 1000-MHz antennas. Then, a thin plastic tarp was placed on the wet sand, a 3-cm layer of dry sand was placed on the tarp, and data collection was repeated. Additional 3-cm layers of dry sand were placed in the tank, with data acquisition after each layer, until the dry sand layer was 15-cm thick. The tank was then excavated, and a basal layer of dry sand was added. Data were again acquired over the dry sand, and the incremental filling of the tank and data acquisition were repeated using 3-cm layers of wet sand. Finally, the entire process was repeated using a basal layer of wet organic soil overlain by dry organic soil and using a basal layer of dry organic soil overlain by wet organic soil. For all air-launch data, the dielectric constant was determined using the amplitudes of the reflection from the soil surface, and Topp's equation was used to convert the dielectric constant to water content. Data analysis is ongoing, but preliminary results indicate that water content can be estimated with reasonable accuracy in both

  11. 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.

  12. 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.

  13. Analysis of modified wet-air oxidation for soil detoxification

    SciTech Connect

    Unterberg, W.; Willms, R.S.; Balinsky, A.M.; Reible, D.D.; Wetzel, D.M.

    1987-09-01

    This report presents the results of research on wet-air oxidation as a method for the destruction of hazardous wastes. For organics in the presence of large amounts of water, the water need not be vaporized during wet-air oxidation, an attractive characteristic for energy conservation. The feasibility of using wet-air oxidation was investigated in terms of the effects of temperature, pressure, and the presence or absence of soil on the oxidation rate of three model compounds. Wet-air oxidation is a semi-commercial process that has been used to treat a variety of weakly toxic chemical wastes and for the regeneration of activated carbon. In the study, wet-air oxidation research was carried out in a 1-liter batch reactor at temperatures from 130 to 275/sup 0/C and pressures from 703-1760 x 10/sup 3/ kg/sq m on three substances: m-xylene, tetrachloroethylene (TCE), and malathion, both with and without addition of soil. Any attempt to balance the effect of residence time and the cost of energy requires an accurate description of the oxidation kinetics for the compound or waste stream in question. Due to the sampling technique used during the investigation and the inherent nature of the wet-air oxidation process, a variety of potential problems with the interpretation and analysis of the raw concentration-time data were encountered during the study.

  14. 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.

  15. 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.

  16. 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.

  17. Comparative study of urban development and groundwater condition in coastal areas of Buenos Aires, Argentina

    NASA Astrophysics Data System (ADS)

    Rodrigues Capítulo, Leandro; Carretero, Silvina C.; Kruse, Eduardo E.

    2017-02-01

    The geomorphological evolution of a sand-dune barrier in Buenos Aires, Argentina, is analyzed as a factor regulating the fresh groundwater reserves available. The impact of geomorphological evolution and the consequences for the social and economic development of two coastal areas are assessed. This is one of the most important tourist destinations in the country; for study purposes, it was divided into a northern sector and a southern sector. In the southern sector, the exploitable groundwater is associated with the Holocene and upper Pleistocene geomorphological evolution, which generated three interrelated aquifer units, constituting a system whose useful thickness reaches at least 45 m. In contrast, the northern sector is restricted to two Holocene aquifer units, whose total thickness is on the order of 12 m. The morphological characteristics and the occurrence of the largest fresh groundwater reserves in the southern sector are indicators of better conditions for economic growth, which is mainly reflected on the expansion of real estate ventures. The relationships of transmissivity vs area of real estate ventures (Arev), and total water consumption vs Arev, are indicators for the sustainable management of the water resources. The approach chosen may be used by decision makers in other regions to assess the feasibility of future tourism projects on the basis of the availability of water resources associated with geomorphological features.

  18. [Groundwater].

    PubMed

    González De Posada, Francisco

    2012-01-01

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

  19. 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.

  20. 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).

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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

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

    USGS Publications Warehouse

    Battaglin, William A.; Meyer, Michael T.; Kuivila, Kathryn; 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

  13. 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.

  14. [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

  15. 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

  16. 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

  17. 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.

  18. 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...

  19. 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

  20. 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

  1. Uranium geochemistry in soil and groundwater at the F and H seepage basins

    SciTech Connect

    Serkiz, S.M.; Johnson, W.H.

    1994-09-01

    For 33 years, low activity liquid wastes from the chemical separation areas at the U.S. Department of Energy`s Savannah River Site were disposed of in unlined seepage basins. Soil and associated pore water samples of widely varying groundwater chemistries and contaminant concentrations were collected from the region downgradient of these basins using cone penetrometer technology. Analysis of samples using inductively coupled plasma - mass spectrometry has allowed the investigation of uranium partitioning between the aqueous phase and soil surfaces at this site. The distribution of uranium was examined with respect to the solution and soil chemistry (e.g., pH, redox potential, cation and contaminant concentration) and aqueous-phase chemical speciation modeling. The uranium soil source term at the F- and H-Area Seepage Basins (FHSB) is much smaller than has been used in previous modeling efforts. This should result in a much shorter remediation time and a greater effectiveness of a pump-and-treat design than previously predicted. Distribution coefficients at the (FHSB) were found to vary between 1.2 to 34,000 1 kg{sup {minus}1} for uranium. Differences in sorption of these elements can be explained primarily by changes in aqueous pH and the associated change in soil surface charge. Sorption models were fit directly to sorption isotherms from field samples. All models underestimated the fraction of uranium bound at low aqueous uranium concentrations. Linear models overestimated bound uranium at locations where the aqueous concentration was greater than 500 ppb. Mechanistic models provided a much better estimate of the bound uranium concentrations, especially at high aqueous concentrations. Since a large fraction of the uranium at the site is associated with the low-pH portion of the plume, consideration should be given to pumping water from the lowest pH portions of the plume in the F-Area.

  2. 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

  3. 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

  4. Penetration of herbicides to groundwater in an unconfined chalk aquifer following normal soil applications.

    PubMed

    Johnson, A C; Besien, T J; Bhardwaj, C L; Dixon, A; Gooddy, D C; Haria, A H; White, C

    2001-12-01

    The persistence and penetration of the herbicides isoproturon and chlorotoluron in an unconfined chalk aquifer has been monitored over a 4-year period through soil sampling, shallow coring and groundwater monitoring. Chlorotoluron was applied on plots as a marker compound, having never been used previously on that, or surrounding fields. The fieldsite had a 5 degree slope with soil depths of 0.5 to 1.5 m and a water table between 20 and 5 m from the soil surface. Where the water table was deepest (9-20 m below surface (mbs)) little or no positive herbicide detections were made. However, where the water table was at only 4-5 mbs, a regular pesticide signal of around 0.1 microg/l for isoproturon and chlorotoluron could be distinguished. Over the winter recharge period automatic borehole samplers revealed a series of short-lived peaks of isoproturon and chlorotoluron reaching up to 0.8 microg/l. This is consistent with a preferential flow mechanism operating at this particular part of the field. Such peaks were occurring over 2 years after the last application of these compounds. Shallow coring failed to uncover any significant pesticide pulse moving through the deep unsaturated zone matrix at the fieldsite.

  5. Groundwater flow and contaminant transport modelling at an air weapons range

    NASA Astrophysics Data System (ADS)

    Bordeleau, Geneviève; Martel, Richard; Schäfer, Dirk; Ampleman, Guy; Thiboutot, Sonia

    2008-07-01

    Numerical modelling was done at the Cold Lake Air Weapons Range, Canada, to test whether the dissolved RDX and nitrate detected in groundwater come from the same sources, and to predict whether contamination poses a threat to the surface water receptors near the site. Military live fire training activities may indeed pose a risk of contamination to groundwater resources, however field investigations on military bases are quite recent, and little information is available on the long-term behaviour of munition residues related contaminants. Very limited information was available about the contaminant source zones, which were assigned based on our knowledge of current training activities. The RDX plume was well represented with the model, but the heterogeneous distribution of nitrate concentrations was more difficult to reproduce. It was nonetheless determined that both contaminants originate from the same areas. According to the model, both contaminants should reach the nearby river, but concentrations in the river should remain very low if the source zone concentration does not change. Finally, the model allowed the recommendation of a new location for the main bombing target, which would offer added protection to the river and the lake into which it flows.

  6. 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)

  7. Surface and groundwater quality in the northeastern region of Buenos Aires Province, Argentina

    NASA Astrophysics Data System (ADS)

    Galindo, G.; Sainato, C.; Dapeña, C.; Fernández-Turiel, J. L.; Gimeno, D.; Pomposiello, M. C.; Panarello, H. O.

    2007-04-01

    This work studies the water quality of the Pergamino-Arrecifes River zone in the Rolling Pampa, northeast Buenos Aires Province, Argentina. Temperature, pH, specific conductivity, Na, K, Mg, Ca, SO42-, Cl -, HCO3-, NO3-, Si, Ag, Al, As, B, Ba, Be, Br, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, P, Pb, Se, Tl, U, V, Zn, and the environmental stable δ18O and δ2H isotope ratios were determined in 18 sampling stations. Natural and anthropogenic features influence surface and groundwater quality. Point pollution sources (septic wells and other domestic and farming effluents) increase the nitrate concentration. The values of pH, NO3-, Al, As, B, Fe, and Mn exceed the respective Argentine reference thresholds in different sampling stations for human drinking water; B, Mo, U, and V for irrigation; and V and Zn for cattle consumption.

  8. 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.

  9. 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.

  10. Genesis of hexavalent chromium from natural sources in soil and groundwater

    PubMed Central

    Oze, Christopher; Bird, Dennis K.; Fendorf, Scott

    2007-01-01

    Naturally occurring Cr(VI) has recently been reported in ground and surface waters. Rock strata rich in Cr(III)-bearing minerals, in particular chromite, are universally found in these areas that occur near convergent plate margins. Here we report experiments demonstrating accelerated dissolution of chromite and subsequent oxidation of Cr(III) to aqueous Cr(VI) in the presence of birnessite, a common manganese mineral, explaining the generation of Cr(VI) by a Cr(III)-bearing mineral considered geochemically inert. Our results demonstrate that Cr(III) within ultramafic- and serpentinite-derived soils/sediments can be oxidized and dissolved through natural processes, leading to hazardous levels of aqueous Cr(VI) in surface and groundwater. PMID:17420454

  11. 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.

  12. 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.

  13. Screening-level risk assessment for styrene-acrylonitrile (SAN) trimer detected in soil and groundwater.

    PubMed

    Kirman, C R; Gargas, M L; Collins, J J; Rowlands, J C

    2012-01-01

    A screening-level risk assessment was conducted for styrene-acrylonitrile (SAN) Trimer detected at the Reich Farm Superfund site in Toms River, NJ. Consistent with a screening-level approach, on-site and off-site exposure scenarios were evaluated using assumptions that are expected to overestimate actual exposures and hazards at the site. Environmental sampling data collected for soil and groundwater were used to estimate exposure point concentrations. Several exposure scenarios were evaluated to assess potential on-site and off-site exposures, using parameter values for exposures to soil (oral, inhalation of particulates, and dermal contact) and groundwater (oral, dermal contact) to reflect central tendency exposure (CTE) and reasonable maximum exposure (RME) conditions. Three reference dose (RfD) values were derived for SAN Trimer for short-term, subchronic, and chronic exposures, based upon its effects on the liver in exposed rats. Benchmark (BMD) methods were used to assess the relationship between exposure and response, and to characterize appropriate points of departure (POD) for each RfD. An uncertainty factor of 300 was applied to each POD to yield RfD values of 0.1, 0.04, and 0.03 mg/kg-d for short-term, subchronic, and chronic exposures, respectively. Because a chronic cancer bioassay for SAN Trimer in rats (NTP 2011a) does not provide evidence of carcinogenicity, a cancer risk assessment is not appropriate for this chemical. Potential health hazards to human health were assessed using a hazard index (HI) approach, which considers the ratio of exposure dose (i.e., average daily dose, mg/kg-d) to toxicity dose (RfD, mg/kg-d) for each scenario. All CTE and RME HI values are well below 1 (where the average daily dose is equivalent to the RfD), indicating that there is no concern for potential noncancer effects in exposed populations even under the conservative assumptions of this screening-level assessment.

  14. Nitrogen responses in groundwater, surface water and air following nitrate action plans in the Netherlands and Denmark

    NASA Astrophysics Data System (ADS)

    Broers, H.; Rozemeijer, J.; Visser, A.; Kronvang, B.; Erisman, J. W.; Refsgaard, J.; Thorling, L.; Slomp, C. P.; Prommer, H.

    2012-12-01

    The emissions of nutrients to air and water tend to increase worldwide. Both The Netherlands and Denmark are notorious for large inputs of nutrients in intensive agricultural practice in the previous 60 years. However, both countries have established legislation and action programs to reduce the supply and impacts of nutrients to air, groundwater and surface waters since 1985. This presentation analyses the response of nitrogen in air, surface water and groundwater following these action programs over the period 1985-2010. Responses of agriculturally derived N in air show a significant and rapid decrease since the beginning of these programs. Responses of N concentrations in many Dutch and Danish agriculturally dominated watersheds are also rapid. A clear response of nitrate-N in groundwater was revealed by age dating the water and simulations show that this also leads to a quick response of N outflow to surface waters. The rapid response of surface water is contra dictionary to the generally accepted idea that the slow transport of the groundwater N pool tends to lengthen the time scales necessary for the full recovery of N concentrations in surface waters. We stipulate that the young and shallow component of groundwater flow can discharge previously applied N effectively which causes the improvement of shallow groundwater quality to be reflected in the quick surface water response. While delay of N discharge may be true for areas with thick unsaturated zones and very limited agricultural use close to water courses, this is clearly not the case for areas with pronounced groundwater-surface water interaction such as the Netherlands delta setting or the Danish estuarine setting. The Dutch and Danish results show that N fluxes towards air and water can be managed and effectively monitored, which may help to counteract the increasing nutrient emissions in other densely populated and intensively used parts of the world. In order to predict time scales for recovery, it

  15. 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.

  16. 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...

  17. 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.

  18. Phytoremediation: Using green plants to clean up contaminated soil, groundwater, and wastewater

    SciTech Connect

    Negri, M.C.; Hinchman, R.R.

    1996-05-01

    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 ({open_quotes}organics{close_quotes}), and radioactive compounds in soil or water. Current research at Argonne National Laboratory 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 from Applied Natural Sciences, Inc. (our CRADA partner), 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 {open_quotes}hyperaccumulator{close_quotes} 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.

  19. 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

  20. 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.

  1. 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.

  2. Integrating Raster Based GIS with Land Use, Surface Soil and Rainfall Records for the Estimation of Groundwater Recharge

    NASA Astrophysics Data System (ADS)

    Yu, C. H.; Chen, Y. W.; Chang, L. C.

    2015-12-01

    In Taiwan, groundwater resource plays a vital role in regional water supply because the quantity of groundwater pumpage has exceeded 1/3 of the total quantity of water supply. However, without proper management of groundwater usage, series environmental impacts such as land subsidence and seawater intrusions have occurred. To achieve the goal of sustainable management of groundwater resource, an accurate estimation of groundwater recharge is required. This study proposes to integrate PCRaster with maps of land use and surface soil and rainfall records to determine the spatial and temporal variations of groundwater recharge. PCRaster is a kind of raster based GIS software and its scripting interface is easy to create a spatio-temporal recharge estimation model. In the first step, the map of land use is re-grouped into three categories, impermeable zones, permeable zones and water bodies. For impermeable zones, the recharge quantities are assumed as zeros. Two kinds of estimating equations, a rainfall-infiltration equation and a saturated recharge equation, are respectively used to calculate the recharges of permeable zones and water bodies. The map of surface soil is used to define the spatial distribution of soil parameters in two equations. The temporal records of rainfall define the temporal variable in the rainfall-infiltration equation. The study area is Pingtung Plain which is 1,229 km2 in southern of Taiwan. In the process of estimation, the size of cells is 20 meters by 20 meters. The horizontal of estimation is during 1999 to 2010. The accumulated recharge is about 20.11 billion m3. (1.67 m3/yr). The annual recharge in 2008 is 1.89 billion m3. The annual recharges vary from 1.3 to 2.1 billion m3 because of different hydrological conditions. The infiltrated recharge in May and November in 2008 respectively are 430 (22.73%) and 67 (3.53%) million m3.

  3. 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

  4. 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.

  5. 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.

  6. United States Air Force Environmental Restoration Program. Guidance on Soil Vapor Extraction Optimization

    DTIC Science & Technology

    2001-06-01

    DoD Department of Defense DNAPL Dense non-aqueous phase liquid DPE dual-phase extraction DQO Data quality objective ECD electron capture device...EPA Environmental Protection Agency ER electrical resistance FID flame ionization detector Hg Mercury MCL maximum contaminant level MCLG Maximum...Well Ground Surface Soil (Advection) V a d o s e Z o n e (Diffusion) Massive Clay Sand Sand Vadose Zone Groundwater Zone LNAPL DNAPL Groundwater Table

  7. Rainfall Prediction using Soil and Air Temperature in a Tropical Station

    NASA Astrophysics Data System (ADS)

    Chacko, Tessy P.; Renuka, G.

    2007-07-01

    An attempt is made to establish a linkage between soil and air temperature and south-west monsoon rainfall at Pillicode (12°12'N,75°10'E) a tropical station in north Kerala. The dependence of monsoon rainfall on pre-monsoon soil temperature decreases as the depth of the soil increases. A regression equation has been developed for the estimation of monsoon rainfall using pre-monsoon soil and air temperature. The results show that sub soil temperature along with air temperature can be used for forecasting the monsoon level.

  8. 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.

  9. Improved slant drilling well for in situ remediation of groundwater and soil at contaminated sites.

    PubMed

    Furukawa, Yasuhide; Mukai, Kazuhiro; Ohmura, Keisuke; Kobayashi, Takeshi

    2017-03-01

    Soil contamination has become a crucial issue in urban redevelopment. Japan has many contaminated sites on which manufacturing has been conducted over several decades. Site holders are now under pressure to manage chemical contamination; however, the use of heavy machinery is difficult in remedial operations on restricted sites, especially where there are still working factories. The slant well is a potentially useful technique in such settings, but its use is technically challenging because of the need for high drilling accuracy and the difficulty in sealing the slanted bores. In this study, we investigated an improved technique for slant drilling that can be used around existing structures to treat contaminated soil and groundwater. A key to this novel approach was the use of water-swelling materials as sealants. Research at a test site investigated the accuracy of drilling. Tracer tests were also conducted using sodium chloride and urea. The improved slant borings showed a deviation of less than 2% from the target bore. The spread of the two tracers at different depths was demonstrated. The proposed technique provides a useful approach to the treatment of brownfield sites in countries where in situ remediation has not yet been undertaken.

  10. 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).

  11. 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.

  12. 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.

  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. Untangling the effects of shallow groundwater and soil texture as drivers of subfield-scale yield variability

    NASA Astrophysics Data System (ADS)

    Zipper, Samuel C.; Soylu, Mehmet Evren; Booth, Eric G.; Loheide, Steven P.

    2015-08-01

    Water table depth (WTD), soil texture, and growing season weather conditions all play critical roles in determining agricultural yield; however, the interactions among these three variables have never been explored in a systematic way. Using a combination of field observations and biophysical modeling, we answer two questions: (1) under what conditions can a shallow water table provide a groundwater yield subsidy and/or penalty to corn production?; and (2) how do soil texture and growing season weather conditions influence the relationship between WTD and corn yield?. Subfield-scale yield patterns during a dry (2012) and wet (2013) growing season are used to identify sensitivity to weather. Areas of the field that are negatively impacted by wet growing seasons have the shallowest observed WTD (<1 m), while areas with consistently strong yield have intermediate WTD (1-3 m). Parts of the field that perform consistently poorly are characterized by deep WTD (>3 m) and coarse soil textures. Modeling results find that beneficial impacts of shallow groundwater are more common than negative impacts under the conditions studied, and that the optimum WTD is shallower in coarser soils. While groundwater yield subsidies have a higher frequency and magnitude in coarse-grained soils, the optimum WTD responds to growing season weather at a relatively constant rate across soil types. We conclude that soil texture defines a baseline upon which WTD and weather interact to determine overall yield. Our work has implications for water resource management, climate/land use change impacts on agricultural production, and precision agriculture.

  15. Integrated Field-Scale, Lab-Scale, and Modeling Studies for Improving the Ability to Assess the Groundwater to Indoor Air Pathway at Chlorinated Solvent-Impacted Groundwater Sites

    DTIC Science & Technology

    2012-08-01

    Monitoring of Indoor Air Radon Concentrations with Time .................................14 Radon Concentrations in Soil Gas... Radon soil gas concentration contours [pCi/L] ...........................................................15 Figure 13. SF6 in indoor air with a constant...calibrations ect. August 2010- present* *SF6 started in December 2010, Radon started in February 2011 All available soil gas and

  16. 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.

  17. 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.

  18. 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

  19. Petroleum mass removal from low permeability sediment using air sparging/soil vapor extraction: impact of continuous or pulsed operation

    NASA Astrophysics Data System (ADS)

    Kirtland, Brian C.; Aelion, C. Marjorie

    2000-02-01

    Air sparging and soil vapor extraction (AS/SVE) are innovative remediation techniques that utilize volatilization and microbial degradation to remediate petroleum spills from soils and groundwater. This in situ study investigated the use of AS/SVE to remediate a gasoline spill from a leaking underground storage tank (UST) in the low permeability, clayey soil of the Appalachian Piedmont. The objectives of this study were to evaluate AS/SVE in low permeability soils by quantifying petroleum mass removal rates, monitoring vadose zone contaminant levels, and comparing the mass extraction rates of continuous AS/SVE to 8 and 24 h pulsed operation. The objectives were met by collecting AS/SVE exhaust gas samples and vadose zone air from multi-depth soil vapor probes. Samples were analyzed for O 2, CO 2, BTEX (benzene, toluene, ethylbenzene, xylene), and total combustible hydrocarbon (TCH) concentrations using portable hand meters and gas chromatography. Continuous AS/SVE was effective in removing 608 kg of petroleum hydrocarbons from low permeability soil in 44 days (14.3 kg day -1). Mass removal rates ranged from 2.6 times higher to 5.1 times lower than other AS/SVE studies performed in sandy sediments. BTEX levels in the vadose zone were reduced from about 5 ppm to 1 ppm. Ten pulsed AS/SVE tests removed 78 kg in 23 days and the mean mass removal rate (17.6 kg day -1) was significantly higher than the last 15 days of continuous extraction. Pulsed operation may be preferable to continuous operation because of increased mass removal and decreased energy consumption.

  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. 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.

  2. Diurnal radon variations in the upper soil layers and at the soil-air interface related to meteorological parameters.

    PubMed

    Schubert, M; Schulz, H

    2002-07-01

    Measurements of the radon concentration in a column (1 m2 x 2 m) consisting of a homogeneous mixture of dry sand and uranium tailings have been performed to obtain information on the radon transport under well defined conditions. The dependence of the radon concentration has been exclusively studied on the soil/air temperature gradient and on the wind speed. The soil moisture content has been kept constant. Significant diurnal variations of the radon concentration were detected in the uppermost soil layer and at the soil/air interface. Such a behavior was not found in 30 cm and deeper soil layers. It is argued that the diurnal radon variation in the uppermost soil layer is mainly associated with the diurnal inversion of the soil/air temperature gradient giving rise to a convective soil gas migration additional to the common upward diffusion processes, whereas the diurnal variation of the radon concentration at the soil/air interface is caused by the interplay of the temperature gradient and the wind speed. No impact of atmospheric pressure variations on the radon migration has been observed.

  3. 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.

  4. Thermal separation of soil particles from thermal conductivity measurement under various air pressures

    NASA Astrophysics Data System (ADS)

    Lu, Sen; Ren, Tusheng; Lu, Yili; Meng, Ping; Zhang, Jinsong

    2017-01-01

    The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation.

  5. Thermal separation of soil particles from thermal conductivity measurement under various air pressures.

    PubMed

    Lu, Sen; Ren, Tusheng; Lu, Yili; Meng, Ping; Zhang, Jinsong

    2017-01-05

    The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation.

  6. Thermal separation of soil particles from thermal conductivity measurement under various air pressures

    PubMed Central

    Lu, Sen; Ren, Tusheng; Lu, Yili; Meng, Ping; Zhang, Jinsong

    2017-01-01

    The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation. PMID:28054663

  7. Screening-Level Risk Assessment for Styrene-Acrylonitrile (SAN) Trimer Detected in Soil and Groundwater

    PubMed Central

    Kirman, C. R.; Gargas, M. L.; Collins, J. J.; Rowlands, J. C.

    2012-01-01

    A screening-level risk assessment was conducted for styrene-acrylonitrile (SAN) Trimer detected at the Reich Farm Superfund site in Toms River, NJ. Consistent with a screening-level approach, on-site and off-site exposure scenarios were evaluated using assumptions that are expected to overestimate actual exposures and hazards at the site. Environmental sampling data collected for soil and groundwater were used to estimate exposure point concentrations. Several exposure scenarios were evaluated to assess potential on-site and off-site exposures, using parameter values for exposures to soil (oral, inhalation of particulates, and dermal contact) and groundwater (oral, dermal contact) to reflect central tendency exposure (CTE) and reasonable maximum exposure (RME) conditions. Three reference dose (RfD) values were derived for SAN Trimer for short-term, subchronic, and chronic exposures, based upon its effects on the liver in exposed rats. Benchmark (BMD) methods were used to assess the relationship between exposure and response, and to characterize appropriate points of departure (POD) for each RfD. An uncertainty factor of 300 was applied to each POD to yield RfD values of 0.1, 0.04, and 0.03 mg/kg-d for short-term, subchronic, and chronic exposures, respectively. Because a chronic cancer bioassay for SAN Trimer in rats (NTP 2011a) does not provide evidence of carcinogenicity, a cancer risk assessment is not appropriate for this chemical. Potential health hazards to human health were assessed using a hazard index (HI) approach, which considers the ratio of exposure dose (i.e., average daily dose, mg/kg-d) to toxicity dose (RfD, mg/kg-d) for each scenario. All CTE and RME HI values are well below 1 (where the average daily dose is equivalent to the RfD), indicating that there is no concern for potential noncancer effects in exposed populations even under the conservative assumptions of this screening-level assessment. PMID:23030654

  8. 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.

  9. 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.

  10. 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...

  11. Potential for coal-related groundwater contamination in the Atlantic coastal plain soils of maryland. Final report

    SciTech Connect

    Jennings, A.A.; Kirkner, D.J.; Theis, T.L.

    1984-11-01

    Energy-related wastes such as coal-derived leachates are potential sources of groundwater contamination. These are often relatively high-strength solutions containing trace amounts of environmentally sensitive anions and cations. Recent research has indicated that when solutions of this type are released to soil systems, chemical interactions among solution components can lead to unexpected transport consequences. The research reported on here was designed to evaluate the potential for this type of multicomponent interaction in soils typical of Maryland's Atlantic coastal plain. To accomplish this research, samples from five soils typical of the coastal plain surface deposits, and one sample from the deep Aquia Greensand aquifer were acquired and analyzed. The results of these studies indicated that the surface soils have substantial capacities to attenuate the environmentally sensitive ions typical of coal-derived leachates.

  12. Air and groundwater flow at the interface between fractured host rock and a bentonite buffer

    NASA Astrophysics Data System (ADS)

    Dessirier, B.; Jarsjo, J.; Frampton, A.

    2014-12-01

    Designs of deep geological repositories for spent nuclear fuel include several levels of confinement. The Swedish and Finnish concept KBS-3 targets for example sparsely fractured crystalline bedrock as host formation and would have the waste canisters embedded in an engineered buffer of compacted MX-80 bentonite. The host rock is a highly heterogeneous dual porosity material containing fractures and a rock matrix. Bentonite is a complex expansive porous material. Its water content and mechanical properties are interdependent. Beyond the specific physics of unsaturated flow and transport in each medium, the interface between them is critical. Detailed knowledge of the transitory two-phase flow regime, induced by the insertion of the unsaturated buffer in a saturated rock environment, is necessary to assess the performance of planned KBS-3 deposition holes. A set of numerical simulations based on the equations of two-phase flow for water and air in porous media were conducted to investigate the dynamics of air and groundwater flow near the rock/bentonite interface in the period following installation of the unsaturated bentonite buffer. We assume state of the two-phase flow parameter values for bentonite from laboratory water uptake tests and typical fracture and rock properties from the Äspö Hard rock laboratory (Sweden) gathered under several field characterization campaigns. The results point to desaturation of the rock domain as far as 10 cm away from the interface into matrix-dominated regions for up to 160 days. Similar observations were made during the Bentonite Rock Interaction Experiment (BRIE) at the Äspö HRL, with a desaturation sustained for even longer times. More than the mere time to mechanical and hydraulic equilibrium, the occurrence of sustained unsaturated conditions opens the possibility for biogeochemical processes that could be critical in the safety assessment of the planned repository.

  13. Soil Moisture, Salinity, and Nitrate Control for Soil and Groundwater Protection in Support of Wireless Sensor Networks and Optimal Irrigation Strategy

    NASA Astrophysics Data System (ADS)

    Park, Y.; Harmon, T. C.

    2007-12-01

    Over-irrigation with reclaimed water may cause crop yield reduction and groundwater quality degradation. Continuous and automatic monitoring strategies are desirable as a means of guiding management schemes to avoid these problems. In this work, an optimal irrigation management scheme known as Receding Horizon Control (RHC) is proposed to balance water reuse and soil/groundwater quality. In this scheme, a wireless networked sensor array is deployed to provide on-line feedback to the simulators on which the management algorithm depends. A simulation model including a one- (vertical) dimensional form of the Richards equation coupled to energy and solute transport equations is automatically updated with real-time soil moisture, temperature, nitrate, and salinity sensor data on a regular basis. A genetic algorithm-based control scheme determines the optimal irrigation rate using current observations which continuously maximizes the reclaimed water usage while maintaining salinity and nitrate in soils at a certain level. Results from simulated soil moisture/nitrate control where maximum soil moisture/nitrate level throughout the soil depth is maintained are presented. On-site soil moisture control in Palmdale, CA, where reclaimed water is irrigated with center-pivot irrigation system at an agricultural site, is also demonstrated. An on-going field experiment in Merced, CA where automatic irrigation system is set up to control salinity level in soils is presented as well. The results demonstrate that coupling in situ observations with RHC process control algorithm is a viable strategy for achieving water reuse and agricultural objectives while minimizing negative impacts on environmental quality.

  14. 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...

  15. 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

  16. 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.

  17. 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.

  18. Soil-air exchange model of persistent pesticides in the United States cotton belt.

    PubMed

    Harner, T; Bidleman, T F; Jantunen, L M; Mackay, D

    2001-07-01

    Measurements of organochlorine pesticides (lindane, cis-chlordane [CC], trans-chlordane [TC], trans-nonachlor [TN]), dieldrin, p,p'-dichlorodiphenyldichloroethylene [DDE], and toxaphene) in Alabama, USA, air and soil were used to assess the soil-air equilibrium status and to identify compounds with significant contributions to observed air burdens. Of the compounds tested, p,p'-DDE and toxaphene showed a significant potential for outgasing, followed by dieldrin and trans-nonachlor, which showed moderate outgasing potentials. Lindane, cis-chlordane, and trans-chlordane were near soil-air equilibrium. A fugacity-based, multilayered soil-air exchange model was used to predict temporal trends of chemical in air and soil resulting from reemission of soil residues to a presumed clean atmosphere (maximum emission scenario). Results showed that p,p'-DDE and toxaphene accounted for up to 50% of the observed air burden and that approximately 200 to 600 kg of p,p'-DDE and 3,000 to 11,000 kg to toxaphene are released to the atmosphere each year by soils in Alabama (area = 1.23 x 10(11) m2). High annual net fluxes were also predicted for dieldrin and trans-nonachlor (300-1,100 kg and 150-500 kg, respectively), but these only account for up to approximately 20% of their observed air burdens.

  19. 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

  20. 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

    2008-06-06

    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.

  1. Comparison of field soil vapor results with laboratory ground water and soil results at a former air force rocket engine test cell, Chanute Air Force Base, IL

    SciTech Connect

    Thies, G.J. ); Bailey, W.M.; Madaj, A.J. III

    1993-10-01

    A soil vapor survey utilizing 276 survey points was performed at the site to help determine the areal extent of soil and ground-water contamination. Survey results indicated a VOC anomaly approximately four acres in size present at the eastern end of the site. Historical information supported the soil vapor results in that the eastern portion of the site was the most active during engine testing activities. The most common and abundant VOC identified was TCE. The highest TCE concentration detected was 12.8 ppm. Forty subsurface soil samples were collected from the anomaly area. The most common VOC detected was again TCE at a maximum concentration of 84 [mu]g/kg. Fourteen temporary monitoring wells and 13 permanent wells were installed and sampled to determine the horizontal and vertical extent of contamination. One well was installed in the source area to determine the maximum contaminant concentrations. TCE was again the most common VOC detected with a maximum concentration of 4000 [mu]g/1. Isoconcentration maps for VOCs in the three media (soil vapor, ground water, and soil) all overlay very closely indicating a distinct anomaly at the eastern end of the site. Field soil vapor results are supported by laboratory analytical results for soil and ground water in terms of compounds detected and location of anomaly.

  2. 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...

  3. Preliminary development of a GIS-tool to assess threats to shallow groundwater quality from soil pollutants in Glasgow, UK (GRASP).

    NASA Astrophysics Data System (ADS)

    Dochartaigh, B. É. Ó.; Fordyce, F. M.; Ander, E. L.; Bonsor, H. C.

    2009-04-01

    The protection of groundwater and related surface water quality is a key aspect of the European Union Water Framework Directive and environmental legislation in many countries worldwide. Globally, the protection of urban groundwater resources and related ecosystem services is of growing concern as urbanisation increases. Although urban areas are often where groundwater resources are most in need of protection, there is frequently a lack of information about threats to groundwater quality. Most studies of soil and groundwater contamination, although detailed, are site-specific, and city-wide overviews are generally lacking. The British Geological Survey (BGS) is currently undertaking the Clyde Urban Super-Project (CUSP), delivering multi-disciplinary geoscience products for the Glasgow conurbation. Under this project, a GIS-based prioritisation tool known as GRASP (GRoundwater And Soil Pollutants) has been trialled to aid urban planning and sustainable development by providing a broad-scale assessment of threats to groundwater quality across the conurbation. GRASP identifies areas where shallow groundwater quality is at greatest threat from the leaching and downward movement of potentially harmful metals in the soil. Metal contamination is a known problem in many urban centres including Glasgow, which has a long industrial heritage and associated contamination legacy, notably with respect to Cr. GRASP is based primarily upon an existing British Standard - International Standards Organisation methodology to determine the leaching potential of metals from soils, which has been validated for 11 metals: Al, Fe, Cd, Co, Cr, Cu, Hg, Ni, Mn, Pb and Zn (BS-ISO 15175:2004). However, the GRASP tool is innovative as it combines assessments of soil leaching potential with soil metal content data to highlight threats to shallow groundwater quality. The input parameters required for GRASP (soil pH, clay, organic matter, sesquioxide and metal content) are based upon a systematic

  4. 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.

  5. Expedited soil remediation employing soil vapor extraction and bioventing at Castle Air Force Base

    SciTech Connect

    Hoge, J.

    1996-12-31

    Soil vapor extraction (SVE) involves in-situ removal and treatment of volatile organic compounds (VOCs) from the vadose zone. An SVE system includes vent wells screened in the areas of highest contamination, a piping network connecting the vent wells to a SVE treatment unit, blower(s), and a treatment unit. Typical treatment units include granular activated carbon, catalytic oxidation (catox), thermal oxidation and internal combustion (IC) engines. The type of treatment unit selected is a function of the characteristics of the incoming vapor stream. The blower(s) apply vacuum to selected vent wells, resulting in propagation of a pressure gradient some distance from the wells. This is known as the radius of influence. The zone of remediation within this radius of influence is the distance from the well where sufficient flow velocity exists such that timely clean up of VOCs from the vadose zone can occur. Bioventing is most effective in removing petroleum hydrocarbons with less than 10 carbon chains (C10+). Bioventing involves passive or active injection of air into the subsurface, thus promoting the natural biodegradation of residual petroleum hydrocarbons. Passive injection involves opening vent wells to the atmosphere. Active injection is performed by connecting blowers to vent wells, or the existing piping manifold, and injecting air. Bioventing is most effective in promoting natural biodegradation of residual hydrocarbons in compounds with more than C10+ carbon chains. Factors effecting bioventing performance include: (1) Microorganisms (capable of producing enzymes that can degrade the contamination), (2) Energy source (carbon), (3) Electron acceptor (oxygen), (4) Soil moisture, (5) pH, (6) Nutrients, (7) Soil temperature, and (8) Absence of compounds toxic to microorganisms.

  6. 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.

  7. 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.

  8. 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.

  9. Seasonal Exposure to Drought and Air Warming Affects Soil Collembola and Mites

    PubMed Central

    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. PMID:22905210

  10. 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.

  11. Using the natural biodegradation potential of shallow soils for in-situ remediation of deep vadose zone and groundwater.

    PubMed

    Avishai, Lior; Siebner, Hagar; Dahan, Ofer; Ronen, Zeev

    2017-02-15

    In this study, we examined the ability of top soil to degrade perchlorate from infiltrating polluted groundwater under unsaturated conditions. Column experiments designed to simulate typical remediation operation of daily wetting and draining cycles of contaminated water amended with an electron donor. Covering the infiltration area with bentonite ensured anaerobic conditions. The soil remained unsaturated, and redox potential dropped to less than -200mV. Perchlorate was reduced continuously from ∼1150mg/L at the inlet to ∼300mg/L at the outlet in daily cycles. Removal efficiency was between 60 and 84%. No signs of bioclogging were observed during three operation months although occasional iron reduction observed due to excess electron donor. Changes in perchlorate reducing bacteria numbers were inferred from an increased in pcrA gene abundances from ∼10(5) to 10(7) copied per gram at the end of the experiment indicating the growth of perchlorate-reducing bacteria. We proposed that the topsoil may serve as a bioreactor to treat high concentrations of perchlorate from the contaminated groundwater. The treated water that infiltrates from the topsoil through the vadose zone could be used to flush perchlorate from the deep vadose zone into the groundwater where it is retrieved again for treatment in the topsoil.

  12. 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

  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. Evaluating the Effects of Horizontal Spatial Discretization on Interflow in the Soil Zone Using the Richards and Groundwater Flow Equations

    NASA Astrophysics Data System (ADS)

    Henson, W.; Niswonger, R. G.

    2011-12-01

    In many mountainous regions, a large proportion of streamflow originates as shallow subsurface storm flow (interflow) within the shallow soils of hillslopes. Infiltration can accumulate to form perched groundwater within the upper few meters of the soil horizon that drains to streams through both macropores and soil-matrix. Richards Equation has become a commonly used governing equation for simulating interflow in regional-scale models. Recent research has shown that optimal vertical discretization for Richards Equation near land surface and the water table is much smaller than the discretization typically used in basin-scale hydrologic models, yet little is known about optimal horizontal discretization or potential effects of horizontal discretization on interflow solutions. Most of the work related to the effects of discretization on the solution of Richards Equation has focused on the vertical infiltration problem. This study evaluates horizontal spatial discretization effects on interflow predictions using 1) a modified version of GSFLOW and 2) VS2DT. The modified GSFLOW couples Smith-Parlange 1-D infiltration equations with 3-D unconfined groundwater flow equation, whereas VS2DT uses Richards Equation to represent infiltration and variably saturated flow. Interflow solutions and breakthrough at the stream were compared using a model domain similar to Vauclin and others (1979) with horizontal grid resolutions ranging from 0.05-5m and vertical resolutions ranging between 0.05-1m, with horizontal flow path lengths of 25m to the stream. Variable horizontal spatial resolutions affected VS2DT interflow solutions (RMSE up to 0.12) and interflow breakthrough at the stream, whereas GSFLOW solutions were well correlated (RMSE <0.052). Interflow breakthrough was delayed by up to 10 days with increasing resolution in VS2DT, whereas GSFLOW breakthrough was consistently the same day. Results indicate that the solution of Richards Equation for soil-zone interflow is much

  15. Soil column experiments used as a means to assess transport, sorption, and biodegradation of pesticides in groundwater.

    PubMed

    Magga, Zoi; Tzovolou, Dimitra N; Theodoropoulou, Maria A; Dalkarani, Theodora; Pikios, Konstantinos; Tsakiroglou, Christos D

    2008-11-01

    Soil column experiments are used to investigate the fate of three pesticides of high, intermediate, and low solubility in groundwater: N- phosphonomethyl glycine (glyphosate); O,O-diethyl-S-[(ethylthio)methyl]phosphorodithioate (phorate); (2,4-dichlorophenoxy)acetic acid (2,4-D). Feed solutions are prepared by adding each pesticide (100 mg/L glyphosate, 50 micro g/L phorate, 50 mg/L 2,4-D) along with conservative tracer, KBr, in synthetic groundwater. The concentration of the pesticides in effluents is detected by ion chromatography (glyphosate, 2,4-D) and GC-FID (phorate). The Br(-) breakthrough curves are employed to estimate the dispersion coefficient and mean pore velocity in each column. Solute transport and reactive models accounting for equilibrium/non-equilibrium sorption and biodegradation are coupled with inverse modeling numerical codes to estimate the kinetic parameters for all pesticides.

  16. 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.

  17. 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.

  18. Does shift in oxygen level in soil air affect the trace gases emissions?

    NASA Astrophysics Data System (ADS)

    malghani, S.; Gleixner, G.; Trumbore, S.

    2013-12-01

    Biogenic processes in soil such as, trace gasses emissions are influenced by presence or absence of oxygen as it is a dominant final acceptor of electrons for number of biochemical processes. However, it is unknown that trace gases emissions from soil are influenced by the level of oxygen or not. To understand the impact of oxygen level on CO2, CH4 and N2O emissions, five contrasting soils which differ in land use and other properties, were incubated at constant temperature and moisture in an automated chamber measurement system. Automated system continuously (30 mL/min) flushed the chambers holding soil samples with inlet air of known composition and the outlet air, sampling the headspace of the column, was connected to an automated multiport stream selection valve (Valco) that directed the air stream from different columns sequentially to instrumental part (LiCOR6262,PICARRO2101i and PICCARO2301). Other greenhouse gases and isotopes (δ13C & D) of CH4 were sampled weekly using 2L flasks. Oxygen levels in inlet air were switched weekly, started from 20% followed by 10, 5, 2.5, 1, 0%, and all levels were repeated in reverse fashion (from 1 to 20%).The results showed that soil respiration was higher in soils that were rich in soil organic matter with higher microbial biomass. Three out of five soils exhibited a gradual decrease in soil respiration while shifting higher to lower O2 levels but no such impact was recorded during gradual increase in O2 level. The lowest respiration rates in all soil types were recorded under anaerobic conditions. Forest soils were rich in soil organic carbon and respired more CO2 than grassland or cropland soils. All soils oxidized CH4, except one grassland soil which was acidic in nature (pH=4.1), in the presence of O2 at all levels. Amount of CH4 oxidized varied among soil types and was highest in forest soils. Under anaerobic condition CH4 oxidation was not observed in any soil, while two soils (cropland and one grassland) emitted

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Green Remediation Best Management Practices: Soil Vapor Extraction & Air Sparging

    EPA Pesticide Factsheets

    Historically, approximately one-quarter of Superfund source control projects have involved soil vapor extraction (SVE) to remove volatile organic compounds (VOCs) sorbed to soil in the unsaturated (vadose) zone.

  8. 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

  9. Air sparging: Effects of VOCs and soil properties on VOC volatilization

    SciTech Connect

    Chao, K.P.; Ong, S.K.

    1995-12-31

    The effect of the physical-chemical properties of volatile organic compounds (VOCs) and soil on the volatilization of VOCs during air sparging was investigated using a laboratory-scale air sparging system. The variables studied included two types of soils, three different VOCs, and various air flowrates. VOCs used were chloroform, trichloroethylene (TCE), and carbon tetrachloride. As expected, the percent removal efficiencies of VOCs over a 24-h period were proportional to the injected air flowrate and Henry`s law constant. Experimental results also indicated that beyond a certain air flowrate, the mass of TCE removed was similar for the two porous media used in the experiments. The VOCs volatilized from the porous media appeared to be limited by the interfacial surface area of the water-air interface of the air channels. However, other physical processes, such as diffusion, may also be limiting.

  10. Soil-air relationships for toxaphene in the southern United States.

    PubMed

    Bidleman, Terry E; Leone, Andi

    2004-10-01

    Volatilization of toxaphene residues from agricultural soil was investigated at farms in the southern United States by collecting air samples 40 cm above the soil. The concentration of total toxaphene ranged over several orders of magnitude, from <3 to 6,500 ng g(-1) dry weight in soil, and <0.3 to 42 ng m(-3) in air. A log-log plot of total toxaphene concentrations in soil and overlying air showed a significant (p < 0.001) positive relationship, with r2 = 0.73. The soil/air fugacity ratio (FR) for 26 events ranged from 0.4 to 238, exceeded FR = 1.0 (soil/air equilibrium) in 24 events, and exceeded FR = 10 in 17 events. This indicates that toxaphene in air sampled at 40 cm generally was not at equilibrium but undersaturated with respect to the soil. Compared to a technical toxaphene standard, chromatographic profiles of toxaphene residues in soil and air showed alterations due to preferential degradation and volatilization of the components. Peaks matching the retention times of labile octachlorobornanes B8-531 and B8-806 + B8-809 were depleted in both soil and air relative to the more recalcitrant B8-1413 + B8-1945 and B8-2229. For each event, log-log plots were made of the dimensionless soil/air concentration quotient (Q) versus liquid-phase vapor pressure (PL, Pa) for 10 toxaphene components (peaks containing coeluting congeners) that spanned the volatility range of hepta- to nonachlorobornanes. Statistically significant linear relationships were obtained with r2 values for most events ranging from 0.54 to 0.96. Slopes for all but one event ranged from -1.01 to -1.53 and averaged -1.28 +/- 0.20. When regressions were carried out for only components one to nine, which cover the vapor pressure range of most components reported in ambient air, the average slope was reduced to -1.02 +/- 0.15. Previous models of toxaphene emission, transport, and deposition have considered only total toxaphene. These results provide a basis for modeling soil/air exchange on the basis

  11. 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.

  12. 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

  13. Application of a 2D air flow model to soil vapor extraction and bioventing case studies

    SciTech Connect

    Mohr, D.H.; Merz, P.H.

    1995-05-01

    Soil vapor extraction (SVE) is frequently the technology of choice to clean up hydrocarbon contamination in unsaturated soil. A two-dimensional air flow model provides a practical tool to evaluate pilot test data and estimate remediation rates for soil vapor extraction systems. The model predictions of soil vacuum versus distance are statistically compared to pilot test data for 65 SVE wells at 44 sites. For 17 of 21 sites where there was asphalt paving, the best agreement was obtained for boundary conditions with no barrier to air flow at the surface. The model predictions of air flow rates and stream lines around the well allow an estimate of the gasoline removal rates by both evaporation and bioremediation. The model can be used to quickly estimate the effective radius of influence, defined here as the maximum distance from the well where there is enough air flow to remove the contaminant present within the allowable time. The effective radius of influence is smaller than a radius of influence defined by soil vacuum only. For a case study, in situ bioremediation rates were estimated using the air flow model and compared to independent estimates based on changes in soil temperature. These estimate bioremediation rates for heavy fuel oil ranged from 2.5 to 11 mg oil degraded per kg soil per day, in agreement with values in the literature.

  14. PRELIMINARY ASSESSMENT OF WORKER AND AMBIENT AIR EXPOSURES DURING SOIL REMEDIATION TECHNOLOGY DEMONSTRATIONS

    EPA Science Inventory

    Hazardous waste site remediation workers or neighboring residents may be exposed to particulates during the remediation of lead contaminated soil sites. An industrial hygiene survey and air monitoring program for both lead and dust were performed during initial soil sampling acti...

  15. Evaluation of Phytoremediation for Management of Chlorinated Solvents in Soil and Groundwater

    EPA Pesticide Factsheets

    This document is intended to aid regulators, site owners, consultants, neighbors, and other stakeholders in understanding the proper application of planted systems to remediate groundwater contaminated with halogenated solvents.

  16. 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.

  17. 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

  18. CO2 CH4 flux Air temperature Soil temperature and Soil moisture, Barrow, Alaska 2013 ver. 1

    DOE Data Explorer

    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.

  19. 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.

  20. Monitoring and remediating groundwater

    SciTech Connect

    Vedder, M.

    1995-03-01

    Choosing the optimum groundwater remediation process is a site-specific task. A variety of factors--including soil type, water type, water flow, water table levels and contaminant type--influence sampling and treatment techniques. Because underground contaminant plumes must first be characterized and mapped, initial sampling often is a hit or miss proposition. Historical geophysical data can be obtained from many local water boards to supplement the process. Equipment used in sampling includes drilling rigs, depth probes, bailers, sample tubing and well pumps. Once samples are collected, they are preserved with ice and transported to an environmental laboratory for analysis. Common groundwater contaminants include hydrocarbons, solvents, metals and volatile organic compounds. Typical lab analysis methods include gas chromatography and spectrometry. Remediation options include air stripping, carbon adsorption, the use of bacterial cultures, chemical precipitation, ion exchange, reverse osmosis and ultrafiltration.

  1. Analysis of Selected Enhancements for Soil Vapor Extraction

    DTIC Science & Technology

    1997-09-01

    VOCs or semivolatile organic compounds (SVOC) to enhance their removal via SVE or (2) dry soil to increase air permeability. Thermal enhancement ...Air sparging also oxygenates the groundwater and soils , thereby enhancing the potential for biodegradation at sites with contaminants that degrade...the soil , thus volatilizing organics in the soil . The blanket also acts as a surface seal. Down-the-hole heaters have also been used to enhance oil

  2. 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.

  3. 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...

  4. "Death in soil" or what can we learn from groundwater for the genesis of soil organic matter

    NASA Astrophysics Data System (ADS)

    Kaestner, M.; Miltner, A.; Bombach, P.; Schmidt-Brücken, B.

    2009-04-01

    Soil microorganisms do not only catalyze the transformation of plant residues to soil organic matter, but also serve as considerable carbon source for the formation of refractory soil organic matter by providing cell fragments as structural interfacial surfaces in soil systems. After incubation of 13C-labeled Gram negative bacteria in soil for 224 days, we could show that 44% of the bulk carbon remained in soil. 30 - 35 % of the remaining bulk C from Gram negative microbial biomass was stabilized in non-living soil organic matter (SOM). Surprisingly, the added labeled biomass proteins remained in soil almost completely which clearly indicates the stabilization of proteins in cell aggregations being more resistant to biodegradation than free proteins and amino acids. Scanning electron micrographs of the soil showed very rarely intact cells but highly abundant patchy organic cover material of 20 to 50 nm2 size on the mineral surfaces. A possible mechanism for this stabilization and the observed material could be found by analyses of microbial communities and biofilms developing on Biosep? beads within in situ microcosms exposed to contaminated aquifers. Scanning electron micrographs of the developing biofilms on the beads showed the formation of such patchy material found in the soil by fragmentation of empty bacterial cell envelopes (cell walls) and all stages of decay. The fragmentation of these cell walls provided a mechanistic explanation for the observed stabilisation, the genesis of SOM derived from dead bacterial cells, and the enzyme activity always found associated to SOM.

  5. Variation of radon concentrations in soil and groundwater and its correlation with radon exhalation rate from soil in Budhakedar, Garhwal Himalaya

    NASA Astrophysics Data System (ADS)

    Prasad, Ganesh; Prasad, Yogesh; Gusain, G. S.; Badoni, Manjari; Rana, J. M. S.; Ramola, R. C.

    2009-06-01

    Radon was measured in soil-gas and groundwater in the Budhakedar area of Tehri Garhwal, India in summer and winter to obtain the seasonal variation and its correlation with radon exhalation rate. The environmental surface gamma dose rate was also measured in the same area. The radon exhalation rate in the soil sample collected from different geological unit of Budhakedar area was measured using plastic track detector (LR-115 type II) technique. The variation in the radon concentration in soil-gas was found to vary from 1098 to 31,776 Bq.m-3 with an average of 7456 Bq.m-3 in summer season and 3501 to 42883 Bq.m-3 with an average of 17148 Bq.m-3 in winter season. In groundwater, it was found to vary from 8 to 3047 Bq.l-1 with an average value 510 Bq.l-1 in summer and 26 to 2311 Bq.l-1 with an average value 433 Bq.L-1 in winter. Surface gamma dose rate in the study area varied from 32.4 to 83.6 μR.h-1 with an overall mean of 58.7 μ-R.h-1 in summer and 34.6 to 79.3 μR.h-1 with an average value 58.2 μR.h-1 in winter. Radon exhalation rate from collected soil samples was found to vary from 0.1 × 10-5 to 5.7 × 10-5 Bq.kg-1.h-1 with an average of 1.5 × 10-5 Bq.kg-1.h-1 in summer season and 1.7 × 10-5 to 9.6 × 10-5 Bq.kg-1.h-1 with an average of 5.5 × 10-5 Bq.kg-1.h-1. A weak negative correlation was observed between radon exhalation rate from soil and radon concentration in the soil. Radon exhalation rate from the soil was also not found to be correlated with the gamma dose rate, while it shows a positive correlation with radon concentration in water in summer season. Inter-correlations among various parameters are discussed in detail.

  6. 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

  7. Irrigated greywater in an urban sub-division as a potential source of metals to soil, groundwater and surface water.

    PubMed

    Turner, Ryan D R; Warne, Michael St J; Dawes, Les A; Vardy, Suzanne; Will, Geoffrey D

    2016-12-01

    Increased water demands in dry countries such as Australia, have led to increased adoption of various water reuse practices. Irrigation of greywater (all water discharged from the bathrooms, laundry and kitchen apart from toilet waste) is seen as a potential means of easing water demands; however, there is limited knowledge of how greywater irrigation impacts terrestrial and aquatic environments. This study compared four greywater irrigated residential lots to adjacent non-irrigated lots that acted as controls. Accumulation and potential impacts of metals in soil, groundwater and surface water, as a result of greywater irrigation, were assessed by comparing measured concentrations to national and international guidelines. Greywater increased concentrations of some metals in irrigated soil and resulted in As, B, Cr and Cu exceeding guidelines after only four years of irrigation. Movement of metals from the irrigation areas resulted in metal concentrations in groundwater (Al, As, Cr, Cu, Fe, Mn, Ni and Zn) and surface water (Cu, Fe and Zn) exceeding environmental quality guidelines again within four years. These results are unlikely to be universally applicable but indicate the need to consider metals in greywater in order to minimize potential adverse environmental effects from greywater irrigation.

  8. 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.

  9. 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

    2016-11-01

    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.

  10. 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.

  11. 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.

  12. Scale Dependence of Soil Permeability to Air: Measurement Method and Field Investigation

    NASA Astrophysics Data System (ADS)

    Garbesi, Karina; Sextro, Richard G.; Robinson, Allen L.; Wooley, John D.; Owens, Jonathan A.; Nazaroff, William W.

    1996-03-01

    This work investigates the dependence of soil permeability to air 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.

  13. Research on chemical characteristics of soil salt crusts with saline groundwater drip-irrigation in the Tarim Desert Highway Shelterbelt.

    PubMed

    Zhang, Jianguo; Xu, Xinwen; Lei, Jiaqiang; Li, Shengyu

    2013-01-01

    Soil salt crusts are special layers at soil surface which are widely distributed in the Trim Desert Highway Shelterbelt under drip-irrigation with high salinity groundwater. In order to reveal annual variation of their chemical characteristics, soil salt crusts in shelterbelt of different ages in hinterland of the Taklimakan Desert were sampled. SOM, total salt, inions and pH were analyzed. Following results were obtained. SOM of salt crusts increased with the shelterbelt ages, but increasing trend became lower gradually. Total salt, ions, and pH of salt crusts reduced gradually with the shelterbelt ages. Total salt of salt crusts in shelterbelt of different ages was much higher than shifting sandy land. Ions were higher than shifting sandy land, Cl(-), Na(+), and SO4 (2-) increased more obvious, then Mg(2+), K(+), Ca(2+) and HCO3 (-), CO3 (2-) was little and nearly had no change. pH was all alkaline, pH of salt crusts in shelterbelt of 11 years was even lower than shifting sandy land. We can include that the quality of shallow soil (0~30 cm) in the Trim Desert Highway Shelterbelt becomes better gradually.

  14. 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.

  15. 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.

  16. Water-air and soil-air exchange rate of total gaseous mercury measured at background sites

    NASA Astrophysics Data System (ADS)

    Poissant, Laurier; Casimir, Alain

    In order to evaluate and understand the processes of water-air and soil-air exchanges involved at background sites, an intensive field measurement campaign has been achieved during the summer of 1995 using high-time resolution techniques (10 min) at two sites (land and water) in southern Québec (Canada). Mercury flux was measured using a dynamic flux chamber technique coupled with an automatic mercury vapour-phase analyser (namely, Tekran®). The flux chamber shows that the rural grassy site acted primarily as a source of atmospheric mercury, its flux mimicked the solar radiation, with a maximum daytime value of ˜ 8.3 ng m -2 h -1 of TGM. The water surface location (St. Lawrence River site located about 3 km from the land site) shows deposition and evasion fluxes almost in the same order of magnitude (-0.5 vs 1.0 ng m -2 h -1).The latter is influenced to some extent by solar radiation but primarily by the formation of a layer of stable air over the water surface in which some redox reactions might promote evasion processes over the water surface. This process does not appear over the soil surface. As a whole, soil-air exchange rate is about 6-8 fold greater than the water-air exchange.

  17. Evolution of HTO concentrations in soil, vegetation and air during an experimental chronic HT release

    SciTech Connect

    Davis, P.A.; Galeriu, D.C.; Spencer, F.S.; Amiro, B.D.

    1995-10-01

    A small experimental plot was continuously exposed to elevated levels of HT in air over a 12-day period to study the build up and steady-state concentrations of HTO in the environment. HTO concentrations in soil, vegetation and air all showed similar dynamics, increasing gradually over time with temporary decreases during and following rainfall. The relative magnitudes of the soil, vegetation and air concentrations depended on the height at which the air and vegetation were sampled, the depth at which the soil sample was taken and the soil depth over which the plants drew their transpiration water. The system was at or near steady-state in the last two or three days of the release. When averaged over an eight day interval that included periods of rain, the ratios of HTO concentration in soil, foliage and air moisture to HT concentration in air (measured 20 cm above the ground) were typically 0.0014, 0.0010 and 0.0011 (Bq/mL)/(Bq/m{sup 3}) for a cultivated field. 10 refs., 7 figs.

  18. Prediction of soil frost penetration depth in northwest of Iran using air freezing indices

    NASA Astrophysics Data System (ADS)

    Mohammadi, H.; Moghbel, M.; Ranjbar, F.

    2016-11-01

    Information about soil frost penetration depth can be effective in finding appropriate solutions to reduce the agricultural crop damage, transportations, and building facilities. Amongst proper methods to achieve this information are the statistical and empirical models capable of estimating soil frost penetration depth. Therefore, the main objective of this research is to calculate soil frost penetration depth in northwest of Iran during the year 2007-2008 to validate two different models accuracy. To do so, the relationship between air and soil temperature in different depths (5-10-20-30-50-100 cm) at three times of the day (3, 9, and 15 GMT) for 14 weather stations over 7 provinces was analyzed using linear regression. Then, two different air freezing indices (AFIs) including Norwegian and Finn AFI was implemented. Finally, the frost penetration depth was calculated by McKeown method and the accuracy of models determined by actual soil frost penetration depth. The results demonstrated that there is a significant correlation between air and soil depth temperature in all studied stations up to the 30 cm under the surface. Also, according to the results, Norwegian index can be effectively used for determination of soil frost depth penetration and the correlation coefficient between actual and estimated soil frost penetration depth is r = 0.92 while the Finn index overestimates the frost depth in all stations with correlation coefficient r = 0.70.

  19. 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...

  20. Electrical conductivity and depth of groundwater at the Pergamino zone (Buenos Aires Province, Argentina) through vertical electrical soundings and geostatistical analysis

    NASA Astrophysics Data System (ADS)

    Sainato, Claudia; Galindo, Griselda; Pomposiello, Cristina; Malleville, Horacio; de Abelleyra, Diego; Losinno, B.

    2003-06-01

    In the humid Pampean region of Argentina, a rich agricultural zone, the periodic occurrence of droughts of different intensity is one of the most important factors in the variability of crop yield. Because complementary irrigation is a highly efficient resource to increase such yields, an understanding of groundwater resources is important. This knowledge is limited in topographically smooth zones by the absence of outcroppings and observation boreholes. Water conductivity is another limitation factor if the goal is to avoid soil degradation by irrigation and negative effects for animal and human consumption. The aquifers of the northeastern zone of the Buenos Aires province have been studied regionally, but information at the local scale is limited to sparse boreholes. In this work, a survey using vertical electrical soundings was carried out to determine the depth, thickness, and continuity of shallower aquifers. Both a mapping of the water table and the electrical conductivity distribution of free aquifers were achieved from well data and geophysical results using geostatistical techniques. Recharge areas of the aquifer were recognized as those areas with low conductivity and topographic highs. The discharge areas, mainly at the bed of the Pergamino River, have higher values of conductivity; two zones north and south of the city of Pergamino have conductivities greater than 2000 μS cm -1. Isolines of depth to the fresh-salty water interface showed different values over the Pergamino River, with some local maxima at the swamp zone and near Pergamino.

  1. 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

  2. Air-soil exchange of organochlorine pesticides in a sealed chamber.

    PubMed

    Yang, Bing; Han, Baolu; Xue, Nandong; Zhou, Lingli; Li, Fasheng

    2015-01-01

    So far little is known about air-soil exchange under any sealed circumstances (e.g., in plastic and glass sheds), which however has huge implications for the soil-air-plant pathways of persistent organic pollutants including organochlorine pesticides (OCPs). A newly designed passive air sampler was tested in a sealed chamber for measuring the vertical concentration profiles of gaseous phase OCPs (hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs)). Air was sampled at 5, 15, and 30 cm above ground level every 10th day during a 60-day period by deploying polyurethane foam cylinders housed in acrylonitrile butadiene styrene-covered cartridges. Concentrations and compositions of OCPs along the vertical sections indicated a clear relationship with proximity to the mixture of HCHs and DDTs which escapes from the soils. In addition, significant positive correlations were found between air temperatures and concentrations of HCHs and DDTs. These results indicated revolatilization and re-deposition being at or close to dynamic pseudo-equilibrium with the overlying air. The sampler used for addressing air-soil exchange of persistent organic pollutants in any sealed conditions is discussed.

  3. 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.

  4. 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…

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Effect of air sparging on fate and transport of trichloroethylene in chambers with alfalfa plants

    SciTech Connect

    Zhang, Q.; Hu, J.; Erickson, L.E.; Davis, L.C.

    1997-12-31

    To study the effect of air sparging in soil with trichloroethylene present as a dense nonaqueous phase, air was supplied through pipes installed at the bottom of two chambers planted with alfalfa. Air input rate was 2.14 L/m{sup 2}/day. The fate of trichloroethylene (TCE) was investigated by monitoring TCE concentration in both outflow groundwater and soil gas. Comparison of these results with those of the previous study without air sparging indicates that air sparging appreciably increases the groundwater concentration of TCE. The soil gas at the surface shows even greater concentration difference. The flux of TCE to the atmosphere is increased significantly by air input. Accordingly, the authors can conclude that air sparging improved mass transfer of TCE from the nonaqueous phase to groundwater phase. Air sparging appeared to negatively impact the health of the alfalfa because of the elevated TCE present in the vadose zone of the chamber.

  10. Estimating human exposure through multiple pathways from air, water, and soil.

    PubMed

    McKone, T E; Daniels, J I

    1991-02-01

    This paper describes a set of multipathway, multimedia models for estimating potential human exposure to environmental contaminants. The models link concentrations of an environmental contaminant in air, water, and soil to human exposure through inhalation, ingestion, and dermal-contact routes. The relationship between concentration of a contaminant in an environmental medium and human exposure is determined with pathway exposure factors (PEFs). A PEF is an algebraic expression that incorporates information on human physiology and lifestyle together with models of environmental partitioning and translates a concentration (i.e., mg/m3 in air, mg/liter in water, or mg/kg in soil) into a lifetime-equivalent chronic daily intake (CDI) in mg/kg-day. Human, animal, and environmental data used in calculating PEFs are presented and discussed. Generalized PEFs are derived for air----inhalation, air----ingestion, water----inhalation, water----ingestion, water----dermal uptake, soil----inhalation, soil----ingestion, and soil----dermal uptake pathways. To illustrate the application of the PEF expressions, we apply them to soil-based contamination of multiple environmental media by arsenic, tetrachloroethylene (PCE), and trinitrotoluene (TNT).

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. [Fungal biomass estimation in soils from southwestern Buenos Aires province (Argentina) using calcofluor white stain].

    PubMed

    Vázquez, María B; Amodeo, Martín R; Bianchinotti, María V

    Soil microorganisms are vital for ecosystem functioning because of the role they play in soil nutrient cycling. Agricultural practices and the intensification of land use have a negative effect on microbial activities and fungal biomass has been widely used as an indicator of soil health. The aim of this study was to analyze fungal biomass in soils from southwestern Buenos Aires province using direct fluorescent staining and to contribute to its use as an indicator of environmental changes in the ecosystem as well as to define its sensitivity to weather conditions. Soil samples were collected during two consecutive years. Soil smears were prepared and stained with two different concentrations of calcofluor, and the fungal biomass was estimated under an epifluorescence microscope. Soil fungal biomass varied between 2.23 and 26.89μg fungal C/g soil, being these values in the range expected for the studied soil type. The fungal biomass was positively related to temperature and precipitations. The methodology used was reliable, standardized and sensitive to weather conditions. The results of this study contribute information to evaluate fungal biomass in different soil types and support its use as an indicator of soil health for analyzing the impact of different agricultural practices.

  16. 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

  17. Denitrification in Aquifer Soil and Nearshore Marine Sediments Influenced by Groundwater Nitrate

    PubMed Central

    Slater, Jennifer M.; Capone, Douglas G.

    1987-01-01

    We estimated rates of denitrification at various depths in sediments known to be affected by submarine discharge of groundwater, and also in the parent aquifer. Surface denitrification was only measured in the autumn; at 40-cm depth, where groundwater-imported nitrate has been measured, denitrification occurred consistently throughout the year, at rates from 0.14 to 2.8 ng-atom of N g−1 day−1. Denitrification consistently occurred below the zone of sulfate reduction and was sometimes comparable to it in magnitude. Denitrification occurred deep (14 to 40 cm) in the sediments along 30 km of shoreline, with highest rates occurring where groundwater input was greatest. Denitrification rates decreased with distance offshore, as does groundwater influx. Added glucose greatly stimulated denitrification at depth, but added nitrate did not. High rates of denitrification were measured in the aquifer (17 ng-atom of N g−1 day−1), and added nitrate did stimulate denitrification there. The denitrification measured was enough to remove 46% of the nitrate decrease observed between 40- and 14-cm depth in the sediment. PMID:16347361

  18. 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...

  19. 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

  20. 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.

  1. 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.

  2. Threshold velocities for input of soil particles into the air by desert soils

    NASA Astrophysics Data System (ADS)

    Gillette, Dale A.; Adams, John; Endo, Albert; Smith, Dudley; Kihl, Rolf

    1980-10-01

    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: distrubed soils (except disturbed heavy clay soils), sand dunes, alluvial and aeolian sand deposits, disturbed playa soils, skirts of playas, playa centers, and desert pavements (alluvial deposits).

  3. Contact angles at the water-air interface of hydrocarbon-contaminated soils and clay minerals

    NASA Astrophysics Data System (ADS)

    Sofinskaya, O. A.; Kosterin, A. V.; Kosterina, E. A.

    2016-12-01

    Contact angles at the water-air interface have been measured for triturated preparations of clays and soils in order to assess changes in their hydrophobic properties under the effect of oil hydrocarbons. Tasks have been to determine the dynamics of contact angle under soil wetting conditions and to reveal the effect of chemical removal of organic matter from soils on the hydrophilicity of preparations. The potentialities of static and dynamic drop tests for assessing the hydrophilic-hydrophobic properties of soils have been estimated. Clays (kaolinite, gumbrine, and argillite) have been investigated, as well as plow horizons of soils from the Republic of Tatarstan: heavy loamy leached chernozem, medium loamy dark gray forest soil, and light loamy soddy-calcareous soil. The soils have been contaminated with raw oil and kerosene at rates of 0.1-3 wt %. In the uncontaminated and contaminated chernozem, capillary water capacity has been maintained for 250 days. The contact angles have been found to depend on the degree of dispersion of powdered preparation, the main type of clay minerals in the soil, the presence and amount of oxidation-resistant soil organic matter, and the soil-water contact time. Characteristic parameters of mathematical models for drop behavior on triturated preparations have been calculated. Contamination with hydrocarbons has resulted in a reliable increase in the contact angles of soil preparations. The hydrophobization of soil surface in chernozem is more active than in soils poorer in organic matter. The complete restoration of the hydrophilic properties of soils after hydrocarbon contamination is due to the oxidation of easily oxidizable organic matter at the low content of humus, or to wetting during several months in the absence of the mazut fraction.

  4. Ecotoxicological assessment of the potential impact on soil porewater, surface and groundwater from the use of organic wastes as soil amendments.

    PubMed

    Alvarenga, Paula; Mourinha, Clarisse; Farto, Márcia; Palma, Patrícia; Sengo, Joana; Morais, Marie-Christine; Cunha-Queda, Cristina

    2016-04-01

    This study aimed to assess the potential impact on soil porewater, surface and groundwater from the beneficial application of organic wastes to soil, using their eluates and acute bioassays with aquatic organisms and plants: luminescence inhibition of Vibrio fischeri (15 and 30 min), Daphnia magna immobilization (48 h), Thamnocephalus platyurus survival (24 h), and seed germination of Lolium perenne (7 d) and Lactuca sativa (5 d). Some organic wastes' eluates promoted high toxic responses, but that toxicity could not be predicted by their chemical characterization, which is compulsory by regulatory documents. In fact, when organisms were exposed to the water-extractable chemical compounds of the organic wastes, the toxic responses were more connected to the degree of stabilization of the organic wastes, or to the treatment used to achieve that stabilization, than to their contaminant load. That is why the environmental risk assessment of the use of organic wastes as soil amendments should integrate bioassays with eluates, in order to correctly evaluate the effects of the most bioavailable fraction of all the chemical compounds, which can be difficult to predict from the characterization required in regulatory documents. According to our results, some rapid and standardized acute bioassays can be suggested to integrate a Tier 1 ecotoxicological evaluation of organic wastes with potential to be land applied, namely luminescence inhibition of V. fischeri, D. magna immobilization, and the germination of L. perenne and L. sativa.

  5. 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.

  6. Preliminary assessment of worker and ambient air exposures during soil remediation technology demonstration.

    PubMed

    Romine, James D; Barth, Edwin F

    2002-01-01

    Hazardous waste site remediation workers or neighboring residents may be exposed to particulates during the remediation of lead-contaminated soil sites. Industrial hygiene surveys and air monitoring programs for both lead and dust were performed during initial soil sampling activities and during pilot scale technology demonstration activities at two lead-contaminated soil sites to assess whether worker protection or temporary resident relocation would be suggested during any subsequent remediation technology activities. The concentrations of lead and dust in the air during pilot scale technology demonstration studies were within applicable exposure guidelines, including Occupational Health and Safety Administration permissible exposure limits, National Institute for Occupational Safety and Health recommended exposure limits, American Conference of Governmental Industrial Hygiene threshold limit values, and the United States Environmental Protection Agency's National Ambient Air Quality Standards program limits.

  7. Assessment of soil and groundwater impacts by treated urban wastewater reuse. A case study: application in a golf course (Girona, Spain).

    PubMed

    Candela, Lucila; Fabregat, Salvador; Josa, Alejandro; Suriol, Josep; Vigués, Núria; Mas, Jordi

    2007-03-01

    Starting in July 2000, treated wastewater of urban origin has been used for the "Serres de Pals" golf course irrigation (Girona, Spain). To evaluate if the soil and the aquifer underneath are affected by the utilization of this type of water, samples have been taken along a period of several months from the wastewater treatment plant, the stabilization lagoon, groundwater and soil profiles. Analyses have been performed for total coliforms and aerobic bacteria, soil water pressure and soil water content as well as chemical analyses of the irrigation water, aquifer and water of the vadose zone. Soil profiles taken at several times during the study indicate the absence of coliforms except for a short period during summer. In the vadose zone an increase of more than 1000 mg kg(-1) of NaO(2) in the top 60 cm of soil was observed while Cl(-) concentration in the aquifer reached up to 1200 mg l(-1) ten months after starting the irrigation.

  8. 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.

  9. In situ bioremediation of nitrate and perchlorate in vadose zone soil for groundwater protection using gaseous electron donor injection technology.

    PubMed

    Evans, Patrick J; Trute, Mary M

    2006-12-01

    When present in the vadose zone, potentially toxic nitrate and perchlorate anions can be persistent sources of groundwater contamination. Gaseous electron donor injection technology (GEDIT), an anaerobic variation of petroleum hydrocarbon bioventing, involves injecting electron donor gases, such as hydrogen or ethyl acetate, into the vadose zone, to stimulate biodegradation of nitrate and perchlorate. Laboratory microcosm studies demonstrated that hydrogen and ethanol promoted nitrate and perchlorate reduction in vadose zone soil and that moisture content was an important factor. Column studies demonstrated that transport of particular electron donors varied significantly; ethyl acetate and butyraldehyde were transported more rapidly than butyl acetate and ethanol. Nitrate removal in the column studies, up to 100%, was best promoted by ethyl acetate. Up to 39% perchlorate removal was achieved with ethanol and was limited by insufficient incubation time. The results demonstrate that GEDIT is a promising remediation technology warranting further validation.

  10. 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.

  11. 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...

  12. Modelling pesticide volatilization after soil application using the mechanistic model Volt'Air

    NASA Astrophysics Data System (ADS)

    Bedos, Carole; Génermont, Sophie; Le Cadre, Edith; Garcia, Lucas; Barriuso, Enrique; Cellier, Pierre

    Volatilization of pesticides participates in atmospheric contamination and affects environmental ecosystems including human welfare. Modelling at relevant time and spatial scales is needed to better understand the complex processes involved in pesticide volatilization. Volt'Air-Pesticides has been developed following a two-step procedure to study pesticide volatilization at the field scale and at a quarter time step. Firstly, Volt'Air-NH 3 was adapted by extending the initial transfer of solutes to pesticides and by adding specific calculations for physico-chemical equilibriums as well as for the degradation of pesticides in soil. Secondly, the model was evaluated in terms of 3 pesticides applied on bare soil (atrazine, alachlor, and trifluralin) which display a wide range of volatilization rates. A sensitivity analysis confirmed the relevance of tuning to K h. Then, using Volt'Air-Pesticides, environmental conditions and emission fluxes of the pesticides were compared to fluxes measured under 2 environmental conditions. The model fairly well described water temporal dynamics, soil surface temperature, and energy budget. Overall, Volt'Air-Pesticides estimates of the order of magnitude of the volatilization flux of all three compounds were in good agreement with the field measurements. The model also satisfactorily simulated the decrease in the volatilization rate of the three pesticides during night-time as well as the decrease in the soil surface residue of trifluralin before and after incorporation. However, the timing of the maximum flux rate during the day was not correctly described, thought to be linked to an increased adsorption under dry soil conditions. Thanks to Volt'Air's capacity to deal with pedo-climatic conditions, several existing parameterizations describing adsorption as a function of soil water content could be tested. However, this point requires further investigation. Practically speaking, Volt'Air-Pesticides can be a useful tool to make

  13. 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

  14. Virus removal during groundwater recharge: effects of infiltration rate on adsorption of poliovirus to soil

    SciTech Connect

    Vaughn, J.M.; Landry, E.F.; Beckwith, C.A.; Thomas, M.Z.

    1981-01-01

    Studies were conducted to determine the influence of infiltration rate on poliovirus removal during groundwater recharge with tertiary-treated wastewater effluents. Experiments were conducted at a uniquely designed, field-situated test recharge basin facility through which some 62,000 m/sup 3/ of sewage had been previously applied. Recharge at high infiltration rates (75 to 100 cm/h) resulted in the movement of considerable numbers of seeded poliovirus to the groundwater. Moderately reduced infiltration rates (6 cm/h) affected significantly improved virus removal. Very low infiltration rates (0.5 to 1.0 cm/h), achieved by partial clogging of the test basin, yielded the greatest virus removal efficiencies.

  15. An Improved GRACE Terrestrial Water Storage Assimilation System For Estimating Large-Scale Soil Moisture and Shallow Groundwater

    NASA Astrophysics Data System (ADS)

    Girotto, M.; De Lannoy, G. J. M.; Reichle, R. H.; Rodell, M.

    2015-12-01

    The Gravity Recovery And Climate Experiment (GRACE) mission is unique because it provides highly accurate column integrated estimates of terrestrial water storage (TWS) variations. Major limitations of GRACE-based TWS observations are related to their monthly temporal and coarse spatial resolution (around 330 km at the equator), and to the vertical integration of the water storage components. These challenges can be addressed through data assimilation. To date, it is still not obvious how best to assimilate GRACE-TWS observations into a land surface model, in order to improve hydrological variables, and many details have yet to be worked out. This presentation discusses specific recent features of the assimilation of gridded GRACE-TWS data into the NASA Goddard Earth Observing System (GEOS-5) Catchment land surface model to improve soil moisture and shallow groundwater estimates at the continental scale. The major recent advancements introduced by the presented work with respect to earlier systems include: 1) the assimilation of gridded GRACE-TWS data product with scaling factors that are specifically derived for data assimilation purposes only; 2) the assimilation is performed through a 3D assimilation scheme, in which reasonable spatial and temporal error standard deviations and correlations are exploited; 3) the analysis step uses an optimized calculation and application of the analysis increments; 4) a poor-man's adaptive estimation of a spatially variable measurement error. This work shows that even if they are characterized by a coarse spatial and temporal resolution, the observed column integrated GRACE-TWS data have potential for improving our understanding of soil moisture and shallow groundwater variations.

  16. Temporal variations of radon concentration in the saturated soil of Alpine grassland: the role of groundwater flow.

    PubMed

    Perrier, Frédéric; Richon, Patrick; Sabroux, Jean-Christophe

    2009-03-15

    Radon concentration has been monitored from 1995 to 1999 in the soil of the Sur-Frêtes ridge (French Alps), covered with snow from November to April. Measurements were performed at 70 cm depth, with a sampling time of 1 h, at two points: the summit of the ridge, at an altitude of 1792 m, and the bottom of the ridge, at an altitude of 1590 m. On the summit, radon concentration shows a moderate seasonal variation, with a high value from October to April (winter), and a low value from May to September (summer). At the bottom of the ridge, a large and opposite seasonal variation is observed, with a low value in winter and a high value in summer. Fluctuations of the radon concentration seem to be associated with temperature variations, an effect which is largely delusory. Indeed, these variations are actually due to water infiltration. A simplified mixing model is used to show that, at the summit of the ridge, two effects compete in the radon response: a slow infiltration response, rich in radon, with a typical time scale of days, and a fast infiltration of radon-poor rainwater. At the bottom of the ridge, similarly, two groundwater contributions compete: one slow infiltration response, similar to the response seen at the summit, and an additional slower response, with a typical time scale of about a month. This second slower response can be interpreted as the aquifer discharge in response to snow melt. This study shows that, while caution is necessary to properly interpret the various effects, the temporal variations of the radon concentration in soil can be understood reasonably well, and appear to be a sensitive tool to study the subtle interplay of near surface transfer processes of groundwater with different transit times.

  17. United States Air Force Soil Stabilization Index System - A Validation

    DTIC Science & Technology

    1975-01-01

    Tests Results of Strength Tests Results of Freeze-Ihaw Test Results of Wet- Dry Test Long-Term Immersion Test Effect of Sulface on Cement... Dry Test Results of Soil-Cement Mixtures 120 12 Summary of Immersion Test Results of Soil-Cement Mixtures 131 13 Seven-Day St engths and Durabilities...much higher than the strengths after 12 freeze-thaw cycles. The high temperature (160oF) during the drying phase of the wet- dry test may have

  18. 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

  19. Evaluation of available data on the geohydrology, soil chemistry, and ground-water chemistry of Gas Works Park and surrounding region, Seattle, Washington

    USGS Publications Warehouse

    Sabol, M.A.; Turney, G.L.; Ryals, G.N.

    1988-01-01

    Gas Works Park, in Seattle, Washington, is located at the site of an abandon gasification plant on Lake Union. Wastes deposited during 50 years of plant operations (1906-1956) have extended the shore line 100 ft and left the park soil contaminated with a number of hazardous material. Soil contaminants include polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls, pesticides, volatile organic compounds, cyanide, and metals. PAHs and metals have been detected in Lake Union sediments. Maximum total PAH concentrations exceeded 100 million micrograms/kilogram in some places in the soils of the park at 6-inch depths and in some lake sediments. Other contaminants present are much lower in concentrations. The park is on glacial drift overlain by gasification waste materials and clean fill. Waste materials include sand and gravels, mixed with lampblack, oil, bricks, and other industrial wastes. Groundwater flows through the soils and waste toward Lake Union. Vertical groundwater movement is uncertain, but is assumed to be upward near Lake Union. Concentrations of most soil contaminants are probably low in the groundwater and in Lake Union due to the low solubilities and high sorptive characteristics of these contaminants. However, no water quality data are available to confirm this premise. (USGS)

  20. 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.)

  1. Laboratory simulation of recent NAPL spills to investigate radon partition among NAPL vapours and soil air.

    PubMed

    De Simone, Gabriele; Lucchetti, Carlo; Pompilj, Francesca; Galli, Gianfranco; Tuccimei, Paola

    2017-02-01

    Soil radon is employed to trace residual NAPL (Non-Aqueous Phase Liquid) contamination because it is very soluble in these substances and is strongly depleted over polluted volumes of the subsoil. The solubility of radon into NAPL vapors, generally poorly considered, is investigated here, either as growth of radon exhalation from a material contaminated with increasing volumes of kerosene, or as radon partition between liquid kerosene, water and total air, considered ad the sum of kerosene vapors plus air.

  2. 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.

  3. Impact of soil and groundwater corrosion on the Hierakonpolis Temple Town archaeological site, Wadi Abu Sufian, Idfu, Egypt.

    PubMed

    El-Shishtawy, A M; Atwia, M G; El-Gohary, A; Parizek, R R

    2013-06-01

    Hierakonpolis, Greek for City of the Hawk, nearly 25 km NW of Idfu (Egypt), is an important and extensive archaeological discovery covering a large area. Its richness in archaeological artifacts makes it a valuable site. It has a valid claim to be the first nation state, as indicated by the Palette of Narmer discovered in its main mound. Geological and hydrogeological investigations at the Hierakonpolis Temple Town site documented nearly a 4.0-m water table rise from as early as 1892 to the present. In addition to the rising water levels, the increase of both subsoil water salinity and humidity threatens and damages fragile carvings and paintings within tombs in Kingdom Hill, the foundation stability of the site, and the known and still to be discovered artifact that recent pottery finds dates at least 4,000 BCE. Representative rock and soil samples obtained from drilled cores in the study area were chosen for conducting detailed grain size and X-ray analysis, light and heavy mineral occurrences, distribution of moisture and total organic matter, and scanning electron microscopy investigations. Mineralogical analysis of clays indicated that the soil samples are composed of smectite/illite mixed layers with varying proportions of smectite to illite. Kaolinite is the second dominant clay constituent, besides occasional chlorite. Swelling of the clay portion of the soil, due to the presence of capillary groundwater, in contact with buried mudbrick walls expands and causes severe damage to important exposed and buried mudbrick structures, including the massive ancient "fort" believed to date from the Second Dynasty (from 2,890 to 2,686 BC). The "fort" is 1.0 km south of the Temple Town mounds near to confluence of Wadi Abu Sufian. Groundwater samples from the shallow aquifer close by the intersection of Wadi Abu Sufian and the Nile flood plain were analyzed for chemical composition and stable isotope ratios. The groundwater in the upper zone (subsoil water) within fine

  4. Cone Penetration Test and Soil Boring at the Bayside Groundwater Project Site in San Lorenzo, Alameda County, California

    USGS Publications Warehouse

    Bennett, Michael J.; Sneed, Michelle; Noce, Thomas E.; Tinsley, John C.

    2009-01-01

    Aquifer-system deformation associated with ground-water-level changes is being investigated cooperatively by the U.S. Geological Survey (USGS) and the East Bay Municipal Utility District (EBMUD) at the Bayside Groundwater Project (BGP) near the modern San Francisco Bay shore in San Lorenzo, California. As a part of this project, EBMUD has proposed an aquifer storage and recovery (ASR) program to store and recover as much as 3.78x104 m3/d of water. Water will be stored in a 30-m sequence of coarse-grained sediment (the 'Deep Aquifer') underlying the east bay alluvium and the adjacent ground-water basin. Storing and recovering water could cause subsidence and uplift at the ASR site and adjacent areas because the land surface will deform as aquifers and confining units elastically expand and contract with ASR cycles. The Deep Aquifer is overlain by more than 150 m of clayey fine-grained sediments and underlain by comparable units. These sediments are similar to the clayey sediments found in the nearby Santa Clara Valley, where inelastic compaction resulted in about 4.3 m of subsidence near San Jose from 1910 to 1995 due to overdraft of the aquifer. The Deep Aquifer is an important regional resource, and EBMUD is required to demonstrate that ASR activities will not affect nearby ground-water management, salinity levels, or cause permanent land subsidence. Subsidence in the east bay area could induce coastal flooding and create difficulty conveying winter storm runoff from urbanized areas. The objective of the cooperative investigation is to monitor and analyze aquifer-system compaction and expansion, as well as consequent land subsidence and uplift resulting from natural causes and any anthropogenic causes related to ground-water development and ASR activities at the BGP. Therefore, soil properties related to compressibility (and the potential for deformation associated with ground-water-level changes) are of the most concern. To achieve this objective, 3 boreholes

  5. MICROBIOLOGICAL FIELD SAMPLING AND INSTRUMENTATION IN THE ASSESSMENT OF SOIL AND GROUND-WATER POLLUTION

    EPA Science Inventory

    This chapter emphasizes the importance of microbiological sampling of soil and ground water with respect to human heath risks, laws and regulations dealing with safe drinking water, and more prevalent subsurface monitoring activities associated with chlorinated organic compounds,...

  6. Investigation of Chromium and Nickel mobility in serpentinite soils and rocks: Impact into groundwaters and influences of carbonation.

    NASA Astrophysics Data System (ADS)

    Baneschi, Ilaria; Natali, Claudio; Boschi, Chiara; Chiarantini, Laura; Guidi, Massimo

    2013-04-01

    Potentially harmful elements such as Cr and Ni in soils are increasingly drawing the attention of scientists and authorities due to their potential toxicity to humans and ecosystems. In the Tuscany region high levels of Cr in Ni have been reported in ultramafic rocks and soils. Furthermore, concentrations of Cr in groundwater of several aquifer systems of this area can approach the maximum contamination level of 50 µg/l, mainly in the form of Cr (VI). The main mechanism for mobilization Cr (VI) at these sites is the weathering of Cr (III) from ultramafic rock with subsequent oxidation. To characterize the effects of weathering and the accessibility of geologically sourced and potentially toxic Cr and Ni in coastal Tuscany EU and Regione Toscana financed a multidisciplinary project, named RESPIRA. The study of waters, rocks and soils was conducted in the some sites of the coastal area of Tuscany, where concentrations of Cr (VI) in springwaters are around 50 µg/l (like in Querceto and Montecastelli) or below the detection limit, such as in Santa Luce. It has to be noted that at the site of Montecastelli and Querceto carbonation of serpentinite outcrops has been revealed (Boschi, 2011), together with iron rich brucite. Chemical and mineralogical analyses were conducted on rock and soil samples by scanning electron microscopy (SEM), electron microprobe (EMP), X-Ray Fluorescence (XRF) and seven-steps sequential extraction. Extraction analyses were performed to obtain quantitative information on the distribution of trace metals in different mineralogical phases (clay minerals, carbonates, amorphous Fe, Mn oxides, organic matter and other silicates and oxides). The results show that the residual fraction was the predominant form of Cr and Ni in soil and rock samples. However, the concentrations of Ni associated to exchangeable, carbonates, Mn oxides and non cristalline fractions were higher than those of Cr, indicating that Ni was more available than Cr in all samples

  7. 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).

  8. Shallow groundwater and soil chemistry response to 3 years of subsurface drip irrigation using coalbed-methane-produced water

    SciTech Connect

    Bern, C. R.; Boehlke, A. R.; Engle, M. A.; Geboy, N. J.; Schroeder, K. T.; Zupancic, J. W.

    2013-10-04

    Disposal of produced waters, pumped to the surface as part of coalbed methane (CBM) development, is a significant environmental issue in the Wyoming portion of the Powder River Basin, USA. High sodium adsorption ratios (SAR) of the waters could degrade agricultural land, especially if directly applied to the soil surface. One method of disposing of CBM water, while deriving beneficial use, is subsurface drip irrigation (SDI), where acidified CBM waters are applied to alfalfa fields year-round via tubing buried 0.92 m deep. Effects of the method were studied on an alluvial terrace with a relatively shallow depth to water table (~3 m). Excess irrigation water caused the water table to rise, even temporarily reaching the depth of drip tubing. The rise corresponded to increased salinity in some monitoring wells. Three factors appeared to drive increased groundwater salinity: (1) CBM solutes, concentrated by evapotranspiration; (2) gypsum dissolution, apparently enhanced by cation exchange; and (3) dissolution of native Na–Mg–SO{sub 4} salts more soluble than gypsum. Irrigation with high SAR (24) water has increased soil saturated paste SAR up to 15 near the drip tubing. Importantly though, little change in SAR has occurred at the surface.

  9. Shallow groundwater and soil chemistry response to 3 years of subsurface drip irrigation using coalbed-methane-produced water

    USGS Publications Warehouse

    Bern, Carleton R.; Boehlke, Adam R.; Engle, Mark A.; Geboy, Nicholas J.; Schroeder, K.T.; Zupancic, J.W.

    2013-01-01

    Disposal of produced waters, pumped to the surface as part of coalbed methane (CBM) development, is a significant environmental issue in the Wyoming portion of the Powder River Basin, USA. High sodium adsorption ratios (SAR) of the waters could degrade agricultural land, especially if directly applied to the soil surface. One method of disposing of CBM water, while deriving beneficial use, is subsurface drip irrigation (SDI), where acidified CBM waters are applied to alfalfa fields year-round via tubing buried 0.92 m deep. Effects of the method were studied on an alluvial terrace with a relatively shallow depth to water table (∼3 m). Excess irrigation water caused the water table to rise, even temporarily reaching the depth of drip tubing. The rise corresponded to increased salinity in some monitoring wells. Three factors appeared to drive increased groundwater salinity: (1) CBM solutes, concentrated by evapotranspiration; (2) gypsum dissolution, apparently enhanced by cation exchange; and (3) dissolution of native Na–Mg–SO4 salts more soluble than gypsum. Irrigation with high SAR (∼24) water has increased soil saturated paste SAR up to 15 near the drip tubing. Importantly though, little change in SAR has occurred at the surface.

  10. Exposure assessment of heavy metals on abandoned metal mine areas by ingestion of soil, crop plant and groundwater

    NASA Astrophysics Data System (ADS)

    Lee, J.-S.; Chon, H.-T.

    2003-05-01

    In order to assess the risk of adverse health effects on human exposure to arsenic and heavy metals influence by past mining activities, environmental geochemical survey was undertaken in the abandoned metal mine areas (Dongil Au-Ag-Cu-Zn mine, Okdong Cu-Pb-Zn mine, Myungbong Au-Ag mine). Arsenic and other heavy metals were highly elevated in the tailings from the Dongil mine (8,720 As mg/kg, 5.9 Cd mg/kg, 3,610 Cu mg/kg, 5,850 Pb mg/kg, 630 Zn mg/kg). Heavy metals except As from the Okdong mine (53.6 Cd mg/kg, 910 Cu mg/kg, 1,590 Pb mg/kg, 5,720 Zn mg/kg) and As from the Myungbong mine (5,810 As mg/kg) were also elevated. Elevated levels of As, Cd and Zn were also found in agricultural soils from these mine areas. The H.I. (hazard index) values of As and Cd from the Dongil, the Okdong and Myungbong mine areas are higher than 1.0. Therefore, toxic risk for As and Cd exist via exposure (ingestion) of contaminated soil, groundwater and rice grain in these mine areas.

  11. Mixed Redox Catalytic Destruction of Chlorinated Solvents in Soils and Groundwater: From the Laboratory to the Field

    PubMed Central

    Gao, Song; Rupp, Erik; Bell, Suzanne; Willinger, Martin; Foley, Theresa; Barbaris, Brian; Sáez, A. Eduardo; Arnold, Robert G.; Betterton, Eric

    2010-01-01

    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 H2/O2 = 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

  12. Shallow groundwater and soil chemistry response to 3 years of subsurface drip irrigation using coalbed-methane-produced water

    NASA Astrophysics Data System (ADS)

    Bern, C. R.; Boehlke, A. R.; Engle, M. A.; Geboy, N. J.; Schroeder, K. T.; Zupancic, J. W.

    2013-12-01

    Disposal of produced waters, pumped to the surface as part of coalbed methane (CBM) development, is a significant environmental issue in the Wyoming portion of the Powder River Basin, USA. High sodium adsorption ratios (SAR) of the waters could degrade agricultural land, especially if directly applied to the soil surface. One method of disposing of CBM water, while deriving beneficial use, is subsurface drip irrigation (SDI), where acidified CBM waters are applied to alfalfa fields year-round via tubing buried 0.92 m deep. Effects of the method were studied on an alluvial terrace with a relatively shallow depth to water table (˜3 m). Excess irrigation water caused the water table to rise, even temporarily reaching the depth of drip tubing. The rise corresponded to increased salinity in some monitoring wells. Three factors appeared to drive increased groundwater salinity: (1) CBM solutes, concentrated by evapotranspiration; (2) gypsum dissolution, apparently enhanced by cation exchange; and (3) dissolution of native Na-Mg-SO4 salts more soluble than gypsum. Irrigation with high SAR (˜24) water has increased soil saturated paste SAR up to 15 near the drip tubing. Importantly though, little change in SAR has occurred at the surface.

  13. An analytical model for solute transport in an infiltration tracer test in soil with a shallow groundwater table

    NASA Astrophysics Data System (ADS)

    Liang, Ching-Ping; Hsu, Shao-Yiu; Chen, Jui-Sheng

    2016-09-01

    It is recommended that an in-situ infiltration tracer test is considered for simultaneously determining the longitudinal and transverse dispersion coefficients in soil. Analytical solutions have been derived for two-dimensional advective-dispersive transport in a radial geometry in the literature which can be used for interpreting the result of such a tracer test. However, these solutions were developed for a transport domain with an unbounded-radial extent and an infinite thickness of vadose zone which might not be realistically manifested in the actual solute transport during a field infiltration tracer test. Especially, the assumption of infinite thickness of vadose zone should be invalid for infiltration tracer tests conducted in soil with a shallow groundwater table. This paper describes an analytical model for interpreting the results of an infiltration tracer test based on improving the transport domain with a bounded-radial extent and a finite thickness of vadose zone. The analytical model is obtained with the successive application of appropriate integral transforms and their corresponding inverse transforms. A comparison of the newly derived analytical solution against the previous analytical solutions in which two distinct sets of radial extent and thickness of vadose zone are considered is conducted to determine the influence of the radial and exit boundary conditions on the solute transport. The results shows that both the radial and exit boundary conditions substantially affect the trailing segment of the breakthrough curves for a soil medium with large dispersion coefficients. Previous solutions derived for a transport domain with an unbounded-radial and an infinite thickness of vadose zone boundary conditions give lower concentration predictions compared with the proposed solution at late times. Moreover, the differences between two solutions are amplified when the observation positions are near the groundwater table. In addition, we compare our

  14. 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.

  15. Fate and transport of trichloroethane and trichloroethylene contaminated groundwater, building 719, Dover Air Force Base, Delaware

    SciTech Connect

    Melchiorre, K.J.

    1996-08-01

    Trichloroethane and trichloroethylene are common chlorinated aliphatic industrial organic solvents used in degreasing operations. Both are typically found in groundwater environments as a result of leaking underground storage tanks, leachate from landfills, and contaminant migration from hazardous waste dump sites. Transformation by-products are also found in association with trichloroethane and trichloroethylene without any known source other than from reductive dechlorination. Dechlorinated by-products include 1,1-dichloroethane; cis and trans 1,2-dichloroethylene, 1,1-dichloroethylene, chloroethane, and vinyl chloride. Trichloroethane and trichloroethylene and their transformation by-products are suspected human health hazards. Vinyl chloride is a known human carcinogen, while trichloroethylene is considered a probable human carcinogen, and 1,1-dichloroethylene and 1,1-dichloroethane possible human carcinogens.

  16. 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.

  17. 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.

  18. Using in-situ hot air/steam stripping (HASS) of hydrocarbons in soils

    SciTech Connect

    La Mori, P.N.

    1994-12-31

    The remediation of soils containing volatile (VOC) and semi-volatile (SVC) hydrocarbons is most desirably accomplished in-situ, i.e., without removal of the contaminated soils from the ground. This approach mitigates the environmental problem, i.e., does not transport it to another location, and when properly applied, does not impact on the local environment during remediation NOVATERRA has demonstrated commercially an in-situ, hot air/steam stripping (HASS) technology to remove VOC and SVC from soils both in the vadose and saturated zones. The technology consists of a drill tower which injects and mixes steam and hot air continuously into the soil below ground and a method to immediately capture all vapors escaping to the surface and remove the vaporized VOC/SVC using condensation and carbon beds. The air can be recompressed and recycled. The condensed liquid containing hydrocarbons is purified by distillation. The recovered hydrocarbons can be destroyed or recycled. The technology has successfully removed various chlorinated aliphatics and aromatics, glycol ethers, phthalates, polyaromatic compounds, ketones, petroleum hydrocarbons and many other compound types from sand to clay soils to risk based standards; e.g. 1 increased cancer risk in 1,000,000 using currently acceptable risk assessment standards.

  19. 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).

  20. 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...

  1. Salinization of the soil solution decreases the further accumulation of salt in the root-zone of the halophyte Atriplex nummularia Lindl. growing above shallow saline groundwater.

    PubMed

    Alharby, Hesham F; Colmer, Timothy D; Barrett-Lennard, Edward G

    2017-03-30

    Water use by plants in landscapes with shallow saline groundwater may lead to the accumulation of salt in the root-zone. We examined the accumulation of Na(+) and Cl(-) around the roots of the halophyte Atriplex nummularia Lindl. and the impacts of this increasing salinity for stomatal conductance, water use and growth. Plants were grown in columns filled with a sand-clay mixture, and connected at the bottom to reservoirs containing 20, 200 or 400 mM NaCl. At 21 days, Na(+) and Cl(-) concentrations in the soil solution were affected by the salinity of the groundwater, height above the water-table and the root fresh mass density at various soil depths (P < 0.001). However, by day 35 the groundwater salinity and height above the water-table remained significant factors, but the root fresh mass density was no longer significant. Regression of data from the 200 and 400 mM NaCl treatments showed that the rate of Na(+) accumulation in the soil increased until the Na(+) concentration reached ~250 mM within the root-zone; subsequent decreases in accumulation were associated with decreases in stomatal conductance. Salinization of the soil solution therefore had a feedback effect on further salinization within the root-zone.

  2. Sorption and mineralization of S-metolachlor and its ionic metabolites in soils and vadose zone solids: consequences on groundwater quality in an alluvial aquifer (Ain Plain, France).

    PubMed

    Baran, Nicole; Gourcy, Laurence

    2013-11-01

    This study characterizes the transfer of S-metolachlor (SMOC) and its metabolites, metolachlor ethane sulfonic acid (MESA) and metolachlor oxanilic acid (MOXA) to the alluvial aquifer. Sorption and mineralization of SMOC and its two ionic metabolites were characterized for cultivated soils and solids from the vadose (unsaturated) zone in the Ain Plain (France). Under sterile soil conditions, the absence of mineralization confirms the importance of biotic processes in SMOC degradation. There is some adsorption and mineralization of the parent molecule and its metabolites in the unsaturated zone, though less than in soils. For soils, the MESA adsorption constant is statistically higher than that of MOXA and the sorption constants of the two metabolites are significantly lower than that of SMOC. After 246 days, for soils, maximums of 26% of the SMOC, 30% of the MESA and 38% of the MOXA were mineralized. This partly explains the presence of these metabolites in the groundwater at concentrations generally higher than those of the parent molecule for MESA, although there is no statistical difference in the mineralization of the 3 molecules. The laboratory results make it possible to explain the field observations made during 27 months of groundwater quality monitoring (monthly sampling frequency). The evolution of both metabolite concentrations in the groundwater is directly related to recharge dynamics; there is a positive correlation between concentrations and the groundwater level. The observed lag of several months between the signals of the parent molecule and those of the metabolites is probably due to greater sorption of the parent molecule than of its metabolites and/or to degradation kinetics.

  3. Hormones, sterols, and fecal indicator bacteria in groundwater, soil, and subsurface drainage following a high single application of municipal biosolids to a field.

    PubMed

    Gottschall, N; Topp, E; Edwards, M; Payne, M; Kleywegt, S; Russell, P; Lapen, D R

    2013-04-01

    A land application of dewatered municipal biosolids (DMB) was conducted on an agricultural field in fall 2008 at a rate of 22Mg dry weight (dw) ha(-1). Pre- and post- application, hormone, sterol and fecal indicator bacteria concentrations were measured in tile drainage water, groundwater (2, 4, 6m depth), surface soil cores, and DMB aggregates incorporated in the soil (∼0.2m depth) for a period of roughly 1year post-application. Hormones and sterols were detected up to 1year post-application in soil and in DMB aggregates. Hormone (androsterone, desogestrel, estrone) contamination was detected briefly in tile water samples (22d and ∼2months post-app), at lowngL(-1) concentrations (2-34ngL(-1)). Hormones were not detected in groundwater. Sterols were detected in tile water throughout the study period post-application, and multiple fecal sterol ratios suggested biosolids as the source. Coprostanol concentrations in tile water peaked at >1000ngL(-1) (22d post-app) and were still >100ngL(-1) at 6months post-application. Fecal indicator bacteria were detected throughout the study period in tile water, groundwater (⩽2m depth), soil and DMB aggregate samples. These bacteria were strongly linearly related to coprostanol in tile water (R(2)>0.92, p<0.05). The limited transport of hormones and sterols to tile drainage networks may be attributed to a combination of the hydrophobicity of these compounds and limited macroporosity of the field soil. This transitory contamination from hormones and sterols is unlikely to result in any significant pulse exposure risk in subsurface drainage and groundwater.

  4. Application of inorganic-contaminated groundwater to surface soils and compliance with toxicity characteristic (TCLP) regulations

    SciTech Connect

    Bergren, C.L.; Flora, M.A. ); Jackson, J.L.; Hicks, E.M. )

    1991-01-01

    The Westinghouse Savannah River Company (WSRC) is currently implementing a Purged Water Management Program (PWMP) at the Savannah River Site (SRS) near Aiken, South Carolina. A variety of constituents and disposal strategies are being considered. Constituents investigated in the PWMP include radionuclides, organics, and inorganics (As, Ba, Cd, Cr, Pb, Hg, Se, and Ag). One practical disposal alternative is to discharge purged water (all constituents below regulatory levels) to the ground surface near the monitoring well that is being purged. The purpose of this investigation is to determine if long-term application of purged water that contains inorganic constituents (below regulatory levels) to surface soils will result in the accumulation of inorganics such that the soil becomes a hazardous waste according to the Toxicity Characteristic regulations (40 CFR Part 261.24). Two study soils were selected that encompass the range of soils found at the SRS: Lakeland and Orangeburg. Laboratory batch equilibrium studies indicate that the soils, although able to retain a large amount of inorganics, will not exceed Toxicity Characteristic concentrations when subjected to the TCLP. Field studies are underway to confirm this.

  5. Application of inorganic-contaminated groundwater to surface soils and compliance with toxicity characteristic (TCLP) regulations

    SciTech Connect

    Bergren, C.L.; Flora, M.A.; Jackson, J.L.; Hicks, E.M.

    1991-12-31

    The Westinghouse Savannah River Company (WSRC) is currently implementing a Purged Water Management Program (PWMP) at the Savannah River Site (SRS) near Aiken, South Carolina. A variety of constituents and disposal strategies are being considered. Constituents investigated in the PWMP include radionuclides, organics, and inorganics (As, Ba, Cd, Cr, Pb, Hg, Se, and Ag). One practical disposal alternative is to discharge purged water (all constituents below regulatory levels) to the ground surface near the monitoring well that is being purged. The purpose of this investigation is to determine if long-term application of purged water that contains inorganic constituents (below regulatory levels) to surface soils will result in the accumulation of inorganics such that the soil becomes a hazardous waste according to the Toxicity Characteristic regulations (40 CFR Part 261.24). Two study soils were selected that encompass the range of soils found at the SRS: Lakeland and Orangeburg. Laboratory batch equilibrium studies indicate that the soils, although able to retain a large amount of inorganics, will not exceed Toxicity Characteristic concentrations when subjected to the TCLP. Field studies are underway to confirm this.

  6. 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.

  7. A laboratory assessment of air sparging performance on oil-contaminated soil

    SciTech Connect

    Harkness, M.R.; Bracco, A.A.; Ciampa, J.D.

    1995-12-31

    The efficacy of air sparging to remediate a subsurface plume of transformer oil is evaluated in a comprehensive laboratory study. Shake flask assays containing contaminated soil indicated the oil was highly (>80%) biodegradable by indigenous bacteria when oxygen, nitrogen, and phosphorous were supplied. From 50 to 60% of the oil was removed from the soil in a 169-day biodegradation rate study performed in laboratory soil columns designed to mimic air sparged conditions. Maximal total petroleum hydrocarbon (TPH) biodegradation rates of {approximately}70 mg/kg per day were observed in nutrient (N and P) amended columns at 23 C, based upon O{sub 2} uptake and CO{sub 2} production. The total TPH biodegraded in these columns was 3-fold higher than in an unamended control column.

  8. Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: a potential source of geogenic Cr(VI) to groundwater

    USGS Publications Warehouse

    Mills, Christopher T.; Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J.

    2011-01-01

    Concentrations of geogenic Cr(VI) in groundwater that exceed the World Health Organization’s maximum contaminant level for drinking water (50 μg L−1) occur in several locations globally. The major mechanism for mobilization of this Cr(VI) at these sites is the weathering of Cr(III) from ultramafic rocks and its subsequent oxidation on Mn oxides. This process may be occurring in the southern Sacramento Valley of California where Cr(VI) concentrations in groundwater can approach or exceed 50 μg L−1. To characterize Cr geochemistry in the area, samples from several soil auger cores (approximately 4 m deep) and drill cores (approximately 25 m deep) were analyzed for total concentrations of 44 major, minor and trace elements, Cr associated with labile Mn and Fe oxides, and Cr(VI). Total concentrations of Cr in these samples ranged from 140 to 2220 mg per kg soil. Between 9 and 70 mg per kg soil was released by selective extractions that target Fe oxides, but essentially no Cr was associated with the abundant reactive Mn oxides (up to ~1000 mg hydroxylamine-reducible Mn per kg soil was present). Both borehole magnetic susceptibility surveys performed at some of the drill core sites and relative differences between Cr released in a 4-acid digestion versus total Cr (lithium metaborate fusion digestion) suggest that the majority of total Cr in the samples is present in refractory chromite minerals transported from ultramafic exposures in the Coast Range Mountains. Chromium(VI) in the samples studied ranged from 0 to 42 μg kg−1, representing a minute fraction of total Cr. Chromium(VI) content was typically below detection in surface soils (top 10 cm) where soil organic matter was high, and increased with increasing depth in the soil auger cores as organic matter decreased. Maximum concentrations of Cr(VI) were up to 3 times greater in the deeper drill core samples than the shallow auger cores. Although Cr(VI) in these vadose zone soils and sediments was only a

  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. 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.

  12. SERDP and ESTCP Workshop on Vapor Intrusion into Indoor Air from Contaminated Groundwater

    DTIC Science & Technology

    2014-03-01

    mitigating radon and volatile organic compound (VOC) subsurface vapor intrusion. These projects have determined that vapor concentrations can be highly...Validation of More Cost-Effective Methods for Mitigating Radon and VOC Subsurface Vapor Intrusion to Indoor Air Todd McAlary Geosyntec 1045 Morning

  13. Predicting soil fumigant air concentrations under regional and diverse agronomic conditions.

    PubMed

    Cryer, Steven A

    2005-01-01

    SOFEA (SOil Fumigant Exposure Assessment system; Dow AgroSciences, Indianapolis, IN) is a new stochastic numerical modeling tool for evaluating and managing human inhalation exposure potential associated with the use of soil fumigants. SOFEA calculates fumigant concentrations in air arising from volatility losses from treated fields for large agricultural regions using multiple transient source terms (treated fields), geographical information systems (GIS) information, agronomic specific variables, user-specified buffer zones, and field reentry intervals. A modified version of the USEPA Industrial Source Complex Short Term model (ISCST3) is used for air dispersion calculations. Weather information, field size, application date, application rate, application type, soil incorporation depth, pesticide degradation rates in air, tarp presence, field retreatment, and other sensitive parameters are varied stochastically using Monte Carlo techniques to mimic region and crop specific agronomic practices. Regional land cover, elevation, and population information can be used to refine source placement (treated fields), dispersion calculations, and risk assessments. This paper describes the technical algorithms of SOFEA and offers comparisons of simulation predictions for the soil fumigant 1,3-dichloropropene (1,3-D) to actual regional air monitoring measurements from Kern, California. Comparison of simulation results to daily air monitoring observations is remarkable over the entire concentration distribution (average percent deviation of 44% and model efficiency of 0.98), especially considering numerous inputs such as meteorological conditions for SOFEA were unavailable and approximated by neighboring regions. Both current and anticipated and/or forecasted fumigant scenarios can be simulated using SOFEA to provide risk managers and product stewards the necessary information to make sound regulatory decisions regarding the use of soil fumigants in agriculture.

  14. United States Air Force Installation Restoration Program (IRP) strategies for Investigating Migrating Contaminated Groundwater

    DTIC Science & Technology

    1988-09-01

    in a suburb of Niagara Falls, New York, known as Love Canal . It was determined that the chemical landfill located there contained hazardous waste that...Flow at Love Canal , New York," James Mercer determined from the geological data that the Love Canal site was composed of several different layers of... Love Canal was likely [12:4223. This hypothesis was borne out by water and soil testing data analyzed for various locations around the contamination

  15. An environmental screening model to assess the consequences to soil and groundwater from railroad-tank-car spills of light non-aqueous phase liquids.

    PubMed

    Yoon, Hongkyu; Werth, Charles J; Barkan, Christopher P L; Schaeffer, David J; Anand, Pooja

    2009-06-15

    North American railroads transport a wide variety of chemicals, chemical mixtures and solutions in railroad tank cars. In the event of an accident, these materials may be spilled and impact the environment. Among the chemicals commonly transported are a number of light non-aqueous phase liquids (LNAPLs). If these are spilled they can contaminate soil and groundwater and result in costly cleanups. Railroads need a means of objectively assessing the relative risk to the environment due to spills of these different materials. Environmental models are often used to determine the extent of contamination, and the associated environmental risks. For LNAPL spills, these models must account for NAPL infiltration and redistribution, NAPL dissolution and volatilization, and remediation systems such as pump and treat. This study presents the development and application of an environmental screening model to assess NAPL infiltration and redistribution in soils and groundwater, and to assess groundwater cleanup time using a pumping system. Model simulations use parameters and conditions representing LNAPL releases from railroad tank cars. To take into account unique features of railroad-tank-car spill sites, the hydrocarbon spill screening model (HSSM), which assumes a circular surface spill area and a circular NAPL lens, was modified to account for a rectangular spill area and corresponding lens shape at the groundwater table, as well as the effects of excavation and NAPL evaporation to the atmosphere. The modified HSSM was first used to simulate NAPL infiltration and redistribution. A NAPL dissolution and groundwater transport module, and a pumping system module were then implemented and used to simulate the effects of chemical properties, excavation, and free NAPL removal on NAPL redistribution and cleanup time. The amount of NAPL that reached the groundwater table was greater in coarse sand with high permeability than in fine sand or silt with lower permeabilities

  16. Preliminary investigation of soil and ground-water contamination at a U.S. Army Petroleum Training Facility, Fort Lee, Virginia, September-October 1989

    USGS Publications Warehouse

    Wright, W.G.; Powell, J.D.

    1990-01-01

    Fuel-oil constituents in the soil and groundwater at the Fort Lee Petroleum Training Facility near Petersburg, Virginia, were studied by the U.S. Geological Survey (USGS) in cooperation with the Department of Defense, U.S. Army. The study included installation of 25 groundwater monitoring wells and description of groundwater flow patterns of the shallow-aquifer system underlying the facility. Soil and groundwater samples were collected to determine the concentrations of fuel-oil constituents and to determine the potential for off-site migration of the constituents. Total petroleum hydrocarbon concentrations up to 18,400 mg/km were reported in soil samples. Concentrations of benzene in water from wells at the facility were up to 130 micrograms per liter (ug/L), and concentrations of ethylbenzene and xylene were up to 54 and 120 ug/L, respectively. Potential exists for off-site migration of the contaminants and migration of contaminants downward to deeper aquifers. Further investigations of these potential contamination-migration pathways are warranted. Risk identification at the Petroleum Training Facility cannot be properly addressed because the distribution of the fuel-oil constituents has not been fully characterized. Preliminary identification of risk, however is presented by an examination of toxicity data for the chemical constituents reported in the groundwater at the facility. Concentrations of constituents were compared to the maximum contaminant levels (MCLs) for drinking water established by the U.S. Environmental Protection Agency (USEPA). Concentrations of benzene in water from wells at the facility exceed the USEPA 's 5 ug/L MCL by as much as 26 times. Sufficient data are not available to fully design the remedial-action plan for the facility; however, general responses to contamination of the type associated with the facility include no-action, monitoring, institutional controls, removal, and treatment. (USGS)

  17. Responses of soil respiration to elevated CO2, air warming, and changing soil water availability in an old-field grassland

    SciTech Connect

    Wan, Shiqiang; Norby, Richard J; Childs, Joanne; Weltzin, Jake

    2007-01-01

    Responses of soil respiration to atmospheric and climatic change will have profound impacts on ecosystem and global C cycling in the future. This study was conducted to examine effects on soil respiration of the concurrent driving factors of elevated atmospheric CO2 concentration, rising temperature, and changing precipitation in a constructed old-field grassland in eastern Tennessee, USA. Model ecosystems of seven old-field species in 12 open-top chambers (4 m in diameter) were treated with two CO2 (ambient and ambient plus 300 ppm) and two temperature (ambient and ambient plus 3 C) levels. Two split plots with each chamber were assigned with high and low soil moisture levels. During the 19-month experimental period from June 2003 to December 2004, higher CO2 concentration and soil water availability significantly increased mean soil respiration by 35.8% and 15.7%, respectively. The effects of air warming on soil respiration varied seasonally from small reductions to significant increases to no response, and there was no significant main effect. In the wet side of elevated CO2 chambers, air warming consistently caused increases in soil respiration, whereas in other three combinations of CO2 and water treatments, warming tended to decrease soil respiration over the growing season but increase it over the winter. There were no interactive effects on soil respiration among any two or three treatment factors irrespective of testing time period. Temperature sensitivity of soil respiration was reduced by air warming, lower in the wet than the dry side, and not affected by CO2 treatment. Variations of soil respiration responses with soil temperature and soil moisture ranges could be primarily attributable to the seasonal dynamics of plant growth and its responses to the three treatments. Using a conceptual model to interpret the significant relationships of treatment-induced changes in soil respiration with changes in soil temperature and moisture observed in this study

  18. Sources of mercury in groundwater and soils of west Gijón (Asturias, NW Spain).

    PubMed

    González-Fernández, B; Menéndez-Casares, E; Meléndez-Asensio, Mónica; Fernández-Menéndez, Susana; Ramos-Muñiz, F; Cruz-Hernández, P; González-Quirós, A

    2014-05-15

    This work aimed to determine the cause of the presence of high concentrations of mercury in several springs that exhibit a low concentration of metals in the bedrocks of their recharge areas in Gijón, NW Spain and the extent of this contamination. On the basis of geological mapping, different lithological substrata were analysed at the regional scale with the objective of establishing the base level of mercury in natural soils. The mercury content was simultaneously analysed in several water samples, and the following parameters were also determined: major anions and cations, As, Pb, δ(34)S, and δ(18)OSO4. The soils of the recharge area of the springs exhibited Hg concentrations that were higher than the base level established for sandstone at the regional level, and four of the total number of springs analysed exhibited Hg concentrations higher than 1 μg/l. In addition, the sulphate concentration exceeded the values that this type of aquifer shows in other parts of the region. A comparison between the regionally geochemical background of soils and mercury concentration in springs and soils of the study area did not exhibit a direct relationship, suggesting an anthropogenic and timely origin (most likely from industrial emissions) for this metal. The δ(34)S and δ(18)OSO4 values of dissolved sulphate from the springs with a higher Hg concentration also indicate an anthropogenic origin.

  19. Assessment of soil-gas and groundwater contamination at the Gibson Road landfill, Fort Gordon, Georgia, 2011

    USGS Publications Warehouse

    Falls, W. Fred; Caldwell, Andral W.; Guimaraes, Wladmir G.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2012-01-01

    Soil-gas and groundwater assessments were conducted at the Gibson Road landfill in 201 to provide screening-level environmental contamination data to supplement the data collected during previous environmental studies at the landfill. Passive samplers were used in both assessments to detect volatile and semivolatile organic compounds and polycyclic aromatic hydrocarbons in soil gas and groundwater. A total of 56 passive samplers were deployed in the soil in late July and early August for the soil-gas assessment. Total petroleum hydrocarbons (TPH) were detected at masses greater than the method detection level of 0.02 microgram in all samplers and masses greater than 2.0 micrograms in 13 samplers. Three samplers located between the landfill and a nearby wetland had TPH masses greater than 20 micrograms. Diesel was detected in 28 of the 56 soil-gas samplers. Undecane, tridecane, and pentadecane were detected, but undecane was the most common diesel compound with 23 detections. Only five detections exceeded a combined diesel mass of 0.10 microgram, including the highest mass of 0.27 microgram near the wetland. Toluene was detected in only five passive samplers, including masses of 0.65 microgram near the wetland and 0.85 microgram on the southwestern side of the landfill. The only other gasoline-related compound detected was octane in two samplers. Naphthalene was detected in two samplers in the gully near the landfill and two samplers along the southwestern side of the landfill, but had masses less than or equal to 0.02 microgram. Six samplers located southeast of the landfill had detections of chlorinated compounds, including one perchloroethene detections (0.04 microgram) and five chloroform detections (0.05 to0.08 microgram). Passive samplers were deployed and recovered on August 8, 2011, in nine monitoring wells along the southwestern, southeastern and northeastern sides of the landfill and down gradient from the eastern corner of the landfill. Six of the nine

  20. Potential Groundwater Recharge and the Effects of Soil Heterogeneity on Flow at Two Radioactive Waste Management Sites at the Nevada Test Site

    SciTech Connect

    V. Yucel; D. G. Levitt

    2001-11-01

    Two low-level Radioactive Waste Management Sites (RWMSs), consisting of shallow land burial disposal units at the Nevada Test Site (NTS), are managed by Bechtel Nevada for the U.S. Department of Energy, National Nuclear Security Administration. The NTS has an arid climate with annual average precipitation of about 17 cm at the Area 3 RWMS and about 13 cm at the Area 5 RWMS. The vadose zone is about 490 m thick at the Area 3 RWMS, and about 235 m thick at the Area 5 RWMS. Numerous studies indicate that under current climatic conditions, there is generally no groundwater recharge at these sites. Groundwater recharge may occur at isolated locations surrounding the RWMSs, such as in large drainage washes. However, groundwater recharge scenarios (and radionuclide transport) at the RWMSs are modeled in support of Performance Assessment (PA) documents required for operation of each RWMS. Recharge scenarios include conditions of massive subsidence and flooding, and recharge resulting from deep infiltration through bare-soil waste covers. This paper summarizes the groundwater recharge scenarios and travel time estimates that have been conducted in support of the PAs, and examines the effects of soil hydraulic property heterogeneity on flow.

  1. Biosolids, soil, crop, ground-water, and streambed-sediment data for a biosolids-application area near Deer Trail, Colorado, 2002-2003

    USGS Publications Warehouse

    Yager, Tracy J.B.; Smith, David B.; Crock, James G.

    2004-01-01

    In January 1999, the U.S. Geological Survey began an expanded monitoring program near Deer Trail, Colorado, in cooperation with the Metro Wastewater Reclamation District and the North Kiowa Bijou Groundwater Management District. Monitoring components were biosolids, soils, crops, ground water, and streambed sediments. The monitoring program addresses concerns from the public about chemical effects from applications of biosolids to farmland in the Deer Trail, Colorado, area. Constituents of primary concern to the public are arsenic, cadmium, copper, lead, mercury, molybdenum, nickel, selenium, zinc, plutonium, and gross alpha and gross beta activity, and they are included for all monitoring components. This report presents chemical data from the fourth and fifth years of the monitoring program, 2002 through 2003, for biosolids, soils, crops, alluvial and bedrock ground water, and streambed sediment. The ground-water section also includes climate data and water levels. The chemical data include the constituents of highest concern to the public in addition to many other constituents.

  2. PREDICTING OF RISKS OF GROUNDWATER AND SURFACE WATER POLLUTION WITH DIFFERENT CLASSES OF HERBICIDES IN SOIL IN EASTERN EUROPE CLIMATE CONDITIONS.

    PubMed

    Korshun, M; Dema, O; Kucherenko, O; Korshun, O; Garkavyi, S; Pelio, I; Antonenko, A; Velikaia, N

    2016-11-01

    Application of pesticides in modern agriculture is a powerful permanent risk factor for public health and the natural environment. The aim of the study was a comparative hygienic assessment of the danger of contamination of ground and surface water sources with most widely used herbicides of different chemical classes (sulfonylureas, imidazolinones, pirimidinilkarboksilovye compounds semicarbazones). Field hygienic experiments for studying of the residues dynamics of studied herbicides concentration in agrocenosis objects were made by us in different types of soils: chernozem, sod-podzolic, podzolized forest. Then the half-life periods (DT50) of the substances in the soil were calculated. It was found that according to GUS index there is a high probability of leaching into groundwater of sulfonylureas and imidazolinones; according to LEACH index all investigated substances have a high risk of run-off into groundwater and surface water.

  3. Impact of irrigation with high arsenic burdened groundwater on the soil-plant system: Results from a case study in the Inner Mongolia, China.

    PubMed

    Neidhardt, H; Norra, S; Tang, X; Guo, H; Stüben, D

    2012-04-01

    Consequences of irrigation by arsenic (As) enriched groundwater were assigned in the Hetao Plain, part of Chinas' Inner Mongolia Autonomous Region. Examinations followed the As flow path from groundwater to soil and finally plants. A sunflower and a maize field were systematically sampled, each irrigated since three years with saline well water, characterized by elevated As concentrations (154 and 238μgL(-1)). The annual As input per m(2) was estimated as 120 and 186mg, respectively. Compared to the geogenic background, As concentrations increased toward the surface with observed enrichments in topsoil being relatively moderate (up to 21.1mgkg(-1)). Arsenic concentrations in plant parts decreased from roots toward leaves, stems and seeds. It is shown that the bioavailability of As is influenced by a complex interplay of partly counteracting processes. To prevent As enrichment and soil salinization, local farmers were recommended to switch to a less problematic water source.

  4. Changes of soil hydraulic properties from long-term irrigation with desalted brackish groundwater

    NASA Astrophysics Data System (ADS)

    Valdes-Abellan, Javier; Jiménez-Martínez, Joaquin; Candela, Lucila

    2014-05-01

    Long term effects on soil from desalted water irrigation have been assessed in an experimental plot (9 x 5 m2) under semi-arid climate located in Alicante (SE Spain). Water flux monitoring, from volumetric water content and soil pressure head, was performed from two different monitoring strategies. Also, field scale dispersivity was estimated through a BrLi tracer test and by inverse modelling with HYDRUS. Finally, a reactive and multicomponent transport model was developed using HP1 software, coupling of HYDRUS with PHREEQC. From soil profile characterization, three layers were identified, being calcite the most important mineral of the soil solid phase in all them, followed by quartz and gypsum, the latest in low concentration. Reactive transport modelling of major ions supply by irrigation water was performed with the HP1 code. Temporal and spatial variability of saturated hydraulic conductivity were included in the computational process. Chemical results for each time step (precipitation/dissolution of minerals) were used to compute changes in soil porosity and consequently in the hydraulic conductivity, which is used in the following computational time step. Simulations were performed along a 30 years period. Results from field data show that an increase in porosity and saturated hydraulic conductivity can be expected due to the slow but continuous dissolution of gypsum. Calcite dissolution is expected at the root zone (where partial pressure of CO2 is higher) and precipitation occurs below the root zone, where CO2 partial pressure decreases due to the reduction of biological activity. From the baseline case, three different scenarios were proposed: (i) gypsum free profile, (ii) rain-fed irrigation, and (iii) lower CO2 partial pressure at the root zone. For the gypsum free soil profile scenario, the important precipitation of calcite produced below the root zone is not counteract by the gypsum dissolution, which may lead to significant reduction of hydraulic

  5. Changes in acidity and metal geochemistry in soils, groundwater, drain and river water in the Lower Murray River after a severe drought.

    PubMed

    Mosley, Luke M; Fitzpatrick, Rob W; Palmer, David; Leyden, Emily; Shand, Paul

    2014-07-01

    Acid sulfate soils with sulfuric material (pH<4) can have significant impacts on surface water quality and aquatic ecosystems due to low pH and high soluble metal concentrations in runoff and drainage discharges. There has been limited research on the complex geochemical transformations that occur along flow pathways from the soil acidity source to receiving waters. We studied the integrated geochemistry of metals in acid sulfate soils with sulfuric material, groundwater, drain and river water in the Lower Murray River (South Australia) over a 2 year period. The oxidation of an estimated 3500 ha of acid sulfate soils with sulfidic material (pH>4) underlying this former floodplain occurred due to falling river and groundwater levels during the 2006-2010 extreme "millennium" drought. A low pH (<4.5) soil layer was found approximately 1-2.5m below ground level with substantial amounts (up to 0.2 mol H(+)/kg dry weight) of available/soluble acidity and retained acidity in the form of the Fe oxyhydroxy sulfate mineral jarosite. The jarosite appears to be dissolving over time and buffering the sub-surface soil layers at pH≈4. Metal (Fe, Al, Mn) and metalloid (As) lability was greatly increased in the acidic soil layer. Highly acidic and metal rich groundwater (median pH 4.3, Fe, Al, Mn of 0.04-0.52 mmol/L) was observed at the same depths as the acidic soil layers. Nearly all of the dissolved Fe in the groundwater was present as Fe(2+). In the drains, increases in pH and redox potential promoted formation of the Fe oxyhydroxysulfate mineral schwertmannite. This mineral precipitation transferred a portion of the dissolved acidity to the drain sediments. Upon discharge to, and dilution of, the acid drainage in the river, pH neutralisation and rapid oxidation, hydrolysis, and precipitation of solid Al and Fe phases occurred in a localised area. Acidity is persisting (>3 years) following a return to pre-drought water levels.

  6. Regional and Detailed Survey for Radon Activities in Soil-Gas and Groundwater in the Okchon Zone, Korea

    NASA Astrophysics Data System (ADS)

    Je, H.-K.; Chon, H.-T.

    2012-04-01

    The Okchon zone in Korea provides a typical example of natural geological materials enriched in potentially toxic elements including uranium which is parent nuclide for radon gas. For the purpose of radon radioactivity risk assessment, making the map of radon risk grade from Okchon zone, regional and detailed field surveys were carried out during 3 years. The study area is located in the central part of Korea, called the Okchon zone (about 5,100 km2), which occur in a 80km wide, northeast-trending belt that extends across the Korean Peninsula. The Okchon zone is underlain by metasedimentary rocks of unknown age that are composed mainly of black slate, phyllite, shale, and limestone. The three research areas (defined as Boeun, Chungju, and Nonsan) for detailed survey were selected from the results of regional survey. Results of detailed radon survey indicated a wide range of radon activities for soil-gases (148-1,843 pCi/L) and ground waters (23-5,540 pCi/L). About 15 percent of soil-gas samples exceeded 1,000 pCi/L and 84 percent of ground water samples exceeded the MCL (maximum contaminant level) of drinking water, 300 pCi/L, which proposed by U.S. Environmental Protection Agency in 1999. For detailed survey, radon activities of soil-gas and ground water were classified as bedrock geology, based on 1/50,000 geological map and field research. For soil-gas measurements, mean values of radon activity from black slate-shale (789 pCi/L) were highest among the other base rocks. And for groundwater measurements, mean value of radon activities were decreased in the order of granite (1,345 pCi/L) > black shale-slate (915 pCi/L) > metasediments (617 pCi/L). Result of indoor radon measurement from detailed survey areas showed that about 50% of houses exceeded the indoor guideline, 4 pCi/L. For the radon risk assessment in indoor environment showed that probability of lung cancer risk from the houses located on the granite base rock (3.0×10-2) was highest among the other

  7. HCMM energy budget data as a model input for assessing regions of high potential groundwater pollution. [South Dakota

    NASA Technical Reports Server (NTRS)

    Moore, D. G. (Principal Investigator); Heilman, J. L.

    1980-01-01

    The author has identified the following significant results. Day thermal data were analyzed to assess depth to groundwater in the test site. HCMM apparent temperature was corrected for atmospheric effects using lake temperature of the Oahe Reservoir in central South Dakota. Soil surface temperatures were estimated using an equation developed for ground studies. A significant relationship was found between surface soil temperature and depth to groundwater, as well as between the surface soil-maximum air temperature differential and soil water content (% of field capacity) in the 0 cm and 4 cm layer of the profile. Land use for the data points consisted of row crops, small grains, stubble, and pasture.

  8. Predicting bioconcentration of chemicals into vegetation from soil or air using the molecular connectivity index

    SciTech Connect

    Dowdy, D.L.; McKone, T.E.; Hsieh, D.P.H.

    1995-12-31

    Bioconcentration factors (BCFs) are the ratio of chemical concentration found in an exposed organism (in this case a plant) to the concentration in an air or soil exposure medium. The authors examine here the use of molecular connectivity indices (MCIs) as quantitative structure-activity relationships (QSARS) for predicting BCFs for organic chemicals between plants and air or soil. The authors compare the reliability of the octanol-air partition coefficient (K{sub oa}) to the MC based prediction method for predicting plant/air partition coefficients. The authors also compare the reliability of the octanol/water partition coefficient (K{sub ow}) to the MC based prediction method for predicting plant/soil partition coefficients. The results here indicate that, relative to the use of K{sub ow} or K{sub oa} as predictors of BCFs the MC can substantially increase the reliability with which BCFs can be estimated. The authors find that the MC provides a relatively precise and accurate method for predicting the potential biotransfer of a chemical from environmental media into plants. In addition, the MC is much faster and more cost effective than direct measurements.

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

    NASA Astrophysics Data System (ADS)

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

    2000-08-01

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

  10. Brominated flame retardants and perfluoroalkyl acids in groundwater, tile drainage, soil, and crop grain following a high application of municipal biosolids to a field.

    PubMed

    Gottschall, N; Topp, E; Edwards, M; Payne, M; Kleywegt, S; Lapen, D R

    2017-01-01

    Dewatered municipal biosolids (DMB) were applied at a rate of 22Mgdwha(-1) to an agricultural field in fall 2008. Concentrations of polybrominated diphenyl ethers (PBDEs; BDE-47, -99, -100, -153, -154, -183, -197, -207, -209), other brominated flame retardants (BFRs; HBB, PBEB, DBDPE, BTBPE) and perfluoroalkyl acids (PFAAs; PFHxS, PFOS, PFDS, PFOSA, PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA, PFTA) were monitored in tile drainage, groundwater (2m, 4m and 6m depth), soil cores (0-0.3m) pre- and post-application, DMB aggregates incorporated into the soil post-application, and in wheat (Triticum spp.) planted post-application. Several compounds were detected in soil and water pre-application and on a reference field plot. PBDEs, other BFRs and PFAAs were detected in tile drainage and 2m groundwater throughout the post-application study period; a few PBDEs were also detected sporadically at lower depths in groundwater. Some of these compounds had not been detected pre-application, while some exceeded reference field plot/pre-application levels (some significantly (p<0.05) in tile drainage); both cases indicating biosolid-based water contamination. In DMB aggregates, several PBDE congeners were found to have dissipated exponentially, with reductions >90% in many of them within 1year post-application. Exponential dissipation of other BFRs and PFAAs in DMB aggregates were not significant. No PBDEs, other BFRs, or PFAAs were detected in wheat grain.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    storm events. A persistent groundwater plume of water with high NaCl concentrations is present below the SMBs and downgradient in the shallow groundwater aquifer. Concentrations vary seasonally with the highest concentrations in the winter and early spring. Na+ clearly interacts with the cation exchange complex (CEC) along a flowpath between the SMB and the stream. As a result, the Na:Cl ratio falls from 1:1 in groundwater below the SMBs to as low as ~1:10 and also seems to vary seasonally along the flowpath. Preliminary measurements of the CEC show that the Ca:Na ratio decreases by a factor of 2 - 5 in soil and aquifer materials affected by road salt. Preliminary strontium (Sr) isotope data indicate that groundwater and CEC within the road salt plumes are similar to Sr isotope values for seawater and are isotopically distinct from the relatively radiogenic natural weathering Sr isotope signal. Our findings indicate that SMBs increase the residence time of road salt in groundwater and stream systems with potential negative implications for ecosystems downgradient of SMBs.

  12. Organochlorine pesticides in surface soils from obsolete pesticide dumping ground in Hyderabad City, Pakistan: contamination levels and their potential for air-soil exchange.

    PubMed

    Alamdar, Ambreen; Syed, Jabir Hussain; Malik, Riffat Naseem; Katsoyiannis, Athanasios; Liu, Junwen; Li, Jun; Zhang, Gan; Jones, Kevin C

    2014-02-01

    This study was conducted to examine organochlorine pesticides (OCPs) contamination levels in the surface soil and air samples together with air-soil exchange fluxes at an obsolete pesticide dumping ground and the associated areas from Hyderabad City, Pakistan. Among all the sampling sites, concentrations of OCPs in the soil and air samples were found highest in obsolete pesticide dumping ground, whereas dominant contaminants were dichlorodiphenyltrichloroethane (DDTs) (soil: 77-212,200 ng g(-1); air: 90,700 pg m(-3)) and hexachlorocyclohexane (HCHs) (soil: 43-4,090 ng g(-1); air: 97,400 pg m(-3)) followed by chlordane, heptachlor and hexachlorobenzene (HCB). OCPs diagnostic indicative ratios reflect historical use as well as fresh input in the study area. Moreover, the air and soil fugacity ratios (0.9-1.0) at the dumping ground reflecting a tendency towards net volatilization of OCPs, while at the other sampling sites, the fugacity ratios indicate in some cases deposition and in other cases volatilization. Elevated concentrations of DDTs and HCHs at pesticide dumping ground and its surroundings pose potential exposure risk to biological organisms, to the safety of agricultural products and to the human health. Our study thus emphasizes the need of spatio-temporal monitoring of OCPs at local and regional scale to assess and remediate the future adverse implications.

  13. Reactive Transport of the Uranyl Ion in Soils, Sediments, and Groundwater Systems

    SciTech Connect

    Zachara, John M.; Ilton, Eugene S.; Liu, Chongxuan

    2013-05-16

    Uranium is a ubiquitous trace component in rocks ranging from 1.2 to 1.3 µg g-1 in sedimentary rocks, 2.2 to 15 µg g-1 in granites, and 20 to 120 µg g-1 in phosphates (Langmuir, 1997; Plant et al., 1999). Uranium (U) is released to natural waters in dilute concentrations (generally < 10-7 mole L-1) from the weathering of these sources, with water concentrations in uraniferous geologic terrains, such as the southwestern U.S. (USGS, 2011), being higher (~ 10-6.5 mol L-1). Elevated water-borne concentrations are associated with the weathering of natural ore bodies [~10-6 mol L-1; e.g, (Payne and Airey, 2006)], the extraction and mining of U for armaments (Jiang and Aschner, 2009; WHO, 2001) and nuclear fuels [10-6 to 10-3 mol L-1; (Abdelouas et al., 1999)], and the disposal of waste solids and liquids from nuclear fuels reprocessing and arms production [~ 10-6 to 10-2 mol L-1; e.g., (Wan et al., 2009; Zachara et al., 2007)]. The form of U present in natural waters at high concentration is generally the uranyl ion [e.g., UO22+] which is quite soluble. Groundwater in many parts of the world contains dissolved U originating from natural and anthropogenic sources (ATSDR, 2011; EFSA, 2009). Low levels of dissolved U in drinking water are considered a health concern, causing renal and other effects (Kurttio et al., 2002; Kurttio et al., 2005; Limson Zamora et al., 1998; Nriagu et al., 2012; Raymond-Whish et al., 2007; Selden et al., 2009). The U.S. Environmental Protection Agency has established a regulatory drinking water standard of 30 µg L-1 (1.26 x 10-7 mol L-1) or 30 pCi L-1, whichever is exceeded first. The World Health Organization has recommended an even lower drinking water standard of 15 µg L-1 [6.3 x 10-8 mol L-1; (WHO, 2005)]. Human exposure to U through drinking water is expected to rise as world-wide reliance on groundwater sources increase (ESS, 2010).

  14. [Dictyostelids (Eumycetozoa) from soils of Punta Lara, Province of Buenos Aires, Argentina].

    PubMed

    Vadell, E M

    2000-01-01

    Five taxa of dictyostelid cellular slime molds were isolated from soil and litter samples of the relictual gallery forest of Punta Lara (34 degrees 47' S, 58 degrees 1' W), Province of Buenos Aires, Argentina. Dictyostelium lavandulum, D. polycephalum, D. purpureum and Polysphondylium violaceum were identified from most samples studied, whereas D. macrocephalum was isolated only once. Strains were lyophilized and kept in the BAFC Ceparium. Two additional isolated strains were related to D. sphaerocephalum, and to D. mucoroides var. stoloniferum. These species were likewise found, among others, in soils of the Iguazú National Park (Misiones, Argentina) in 1995.

  15. Investigating plantation-induced near-surface soil hydrophobicity and its impact on groundwater recharge in the Nebraska Sand Hills, USA

    NASA Astrophysics Data System (ADS)

    Adane, Z. A.; Nasta, P.; Gates, J. B.

    2014-12-01

    Although numerous studies in diverse environmental settings have demonstrated that plantations tend to reduce soil moisture and recharge rates, research on physical mechanisms affecting these linkages tend to focus mainly on the effects of evapotranspiration and interception. This study investigates the extent of soil hydrophobicity resulting from land use changes and its impact on groundwater recharge in a century-old experimental forest surrounded by grassland in the Northern High Plains (Nebraska National Forest). Water Drop Penetration Tests (WDPT) and Nuclear Magnetic Resonance (NMR) spectroscopy were used to investigate soil hydrophobicity on 50 cm soil cores collected from experimental plots beneath 5 land cover types. WDPT analysis indicated that most near-surface soils (0-12.5 and 12.5-25 cm) beneath pine plots were moderately to strongly hydrophobic. NMR spectroscopy analysis comparing ratios of hydrophobic (3.2-0.5 and 8.5-6.5 ppm) to hydrophilic (6.5-3.2 ppm) regions suggests that surface soils beneath the plantations were uniformly more hydrophobic than grasslands (by ~30 to 260%). Unsaturated zone soil cores were collected from beneath each experimental plot for comparison of hydrophobicity with recharge rates based on chloride and sulfate mass balance. Recharge estimates beneath the plantations (4-10 mm yr-1) represent reductions of 86-94% relative to the surrounding native grassland, suggesting a link between soil hydrophobicity and reduced infiltration beneath the plantations.

  16. Ground-water resources of the Holloman Air Force Base well field area, 1967, New Mexico

    USGS Publications Warehouse

    Ballance, W.C.; Mattick, Robert E.

    1976-01-01

    Water consumption at Holloman Air Force Base (HAFB), N. Mex., reached an all time high in 1964 and 1965. Further increases in withdrawal without expansion of pumping facilities will hasten the chemical deterioration of the ground water pumped from the well fields. Saline water in the well-field area is present on the north and west sides of the potable-water area and in a thin shallow zone that overlies the potable-water sands in part of the potable-water area. The latter source is affecting quality of the water produced from most wells. The saturated thickness of material underlying the Boles well field ranges from about 3 ,500 feet in the western part of the field to about 1,200 feet in the eastern part of the field. In the Douglass and San Andres well fields, the saturated thickness ranges from 3,500 feet to about 300 feet. Expansion of the Boles and San Andres well fields to the east and southeast would move the center of pumping away from the highly saline water to the north and west. This would eliminate overpumping of the present wells that has resulted from the expanded facilities at Holloman Air Force Base. (Woodard-USGS)

  17. They all like it hot: faster cleanup of contaminated soil and groundwater

    SciTech Connect

    Newmark, R., LLNL

    1998-03-01

    Clean up a greasy kitchen spill with cold water and the going is slow. Us hot water instead and progress improves markedly. So it makes sense that cleanup of greasy underground contaminants such as gasoline might go faster if hot water or steam were somehow added to the process. The Environmental Protection Agency named hundreds of sites to the Superfund list - sites that have been contaminated with petroleum products or petroleum products or solvents. Elsewhere across the country, thousands of properties not identified on federal cleanup lists are contaminated as well. Given that under current regulations, underground accumulations of solvent and hydrocarbon contaminants (the most serious cause of groundwater pollution) must be cleaned up, finding a rapid and effective method of removing them is imperative. In the early 1990`s, in collaboration with the School of Engineering at the University of California at Berkeley, Lawrence Livermore developed dynamic underground stripping. This method for treating underground contaminants with heat is much faster and more effective than traditional treatment methods.

  18. Stability of isoproturon, bentazone, terbuthylazine and alachlor in natural groundwater, surface water and soil water samples stored under laboratory conditions.

    PubMed

    Mouvet, C; Jeannot, R; Riolland, H; Maciag, C

    1997-09-01

    The stability of isoproturon, bentazone, terbuthylazine and alachlor was investigated in groundwater (GrW), surface water (SuW) and soil water from the unsaturated zone (SoW). Samples fortified with a low spiking level (LSL) of about 0.3-0.5 microgram/L and a high spiking level (HSL) of about 0.9-1.3 micrograms/L were stored for 1, 2, 14 (GrW) and 30 days (SuW and SoW) at 4 degrees C in amber glass bottles without biological inhibition. The initial pesticide concentration played a significant role, the lowest concentrations being the least stable for all pesticides. Nevertheless, after 14 days of storage, no concentration had decreased significantly compared to day 0 values, except for bentazone LSL in the GrW and SuW. Significant losses of alachlor were observed only after 30 days. Terbuthylazine and isoproturon were stable for 30 days, except for a slight loss of terbuthylazine HSL in the SoW. The very poor recovery of bentazone from the SoW gave poor results for interpretation. Overall, the stability of the molecules was highest in the GrW and lowest in the SoW. For SoW, the variability of triplicate determinations at a given storage time was, in some cases, as great as the changes in mean concentrations observed over the total 30 day storage period.

  19. Determination of methyl isocyanate in outdoor residential air near metam-sodium soil fumigations.

    PubMed

    Woodrow, James E; LePage, Jane T; Miller, Glenn C; Hebert, Vincent R

    2014-09-10

    The soil fumigant metam-sodium (CH3NHCS2Na) produces the bioactive respiratory irritant methyl isothiocyanate (MITC). Recent laboratory gas-phase oxidative studies indicate that MITC rapidly transforms to the more toxic methyl isocyanate (MIC) in the lower atmosphere. Inhalation exposure risks from MITC plus MIC may therefore be an occupational worker and/or bystander health concern. To address this concern, MIC was monitored, along with MITC, in outdoor residential air in Washington state during the peak fall metam fumigation season. XAD-7 cartridges, coated with 1-(2-pyridyl)piperazine, were developed to retain MIC as its stable substituted urea derivative. Of the 68 residential air measurements of MIC, 15 (22%) were observed to be above the California Environmental Protection Agency's chronic inhalation reference level of 1 μg/m(3), with an observed maximum MIC air concentration of 4.4 μg/m(3). This study indicates MIC air concentrations can be anticipated along with MITC in residential air where seasonal metam soil fumigant applications occur.

  20. Quantitative Passive Diffusive Sampling for Assessing Soil Vapor Intrusion to Indoor Air

    DTIC Science & Technology

    2012-03-28

    4/11/2012 1 Quantitative Passive Diffusive Sampling for Assessing Soil Vapor Intrusion to Indoor Air Todd McAlary and Hester Groenevelt, Geosyntec... Intrusion to Indoor Air 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK...10-6 risk (ppb) Vapour pressure (atm) Water solubility (g/l) 1,1,1-Trichloroethane 110 400 0.16 1.33 1,2,4-Trimethylbenzene

  1. Processes affecting soil and groundwater contamination by DNAPL in low-permeability media

    SciTech Connect

    McWhorter, D.B.

    1996-08-01

    This paper is one of a set of focus papers intended to document the current knowledge relevant to the contamination and remediation of soils and ground water by dense, nonaqueous phase liquids (DNAPL). The emphasis is on low permeability media such as fractured clay and till and unconsolidated, stratified formations. Basic concepts pertaining to immiscible-fluid mixtures are described and used to discuss such aspects as DNAPL transport, dissolved-phase transport, and equilibrium mass distributions. Several implications for remediation are presented. 27 refs., 8 figs., 4 tabs.

  2. Effects of drying and air-dry storage of soils on their capacity for denitrification of nitrate

    SciTech Connect

    Patten, D.K.; Bremner, J.M.; Blackmer, A.M.

    1980-01-01

    The effects of drying and air-dry storage of soils on their capacity for denitrification of nitrate were studied by determining the influence of these pretreatments on the ability of soils to reduce nitrate to gaseous forms of nitrogen (N/sub 2/, N/sub 2/O, and NO) when incubated anaerobically with nitrate for various times. It was found that drying of soils markedly increases their capacity for denitrification of nitrate under anaerobic conditions and that the effect observed increases as the temperature of drying is increased from 25/sup 0/ to 100/sup 0/C. Partial drying of soils and storage of air-dried soils also lead to a significant increase in their ability to denitrify nitrate under anaerobic conditions. Determination of the CO/sub 2/ produced when field-moist, partly dried, air-dried, and air-dried and stored soils were incubated anaerobically with nitrate showed that production of CO/sub 2/ was very highly correlated with production of (N/sub 2/O + N/sub 2/)-N. This suggests that drying and air-dry storage of soils increase their capacity to denitrify nitrate under anaerobic conditions by increasing the amount of soil organic matter readily utilized by denitrifying microorganisms.

  3. Determining long-term effective groundwater recharge by analyzing vertical soil temperature profiles at meteorological stations

    NASA Astrophysics Data System (ADS)

    Cheviron, Bruno; Guérin, Roger; Tabbagh, Alain; Bendjoudi, Hocine

    2005-09-01

    Vertical water seepage in soils results in convective heat transport that modifies the temperature profiles and their variations with time; consequently, there is a relationship between temperature profile variations with time and the vertical Darcy velocity associated with the seepage. Considering the annual sinusoidal time variation of the temperature at the soil surface, it can be shown that convective heat transport has a significant effect on the amplitude damping with depth and a negligible effect on the phase lag with depth of the temperature time signal. Standard meteorological stations constitute a relatively dense network, and we show that their routinely collected data can be used to determine an average value of the vertical Darcy velocity, uz, representing the effective annual recharge over long time periods (several years). A new procedure for determining uz from these temperature records is presented. First, the layering of the medium is determined by an electrical sounding. Then the thermal properties of each layer are inferred from the phase lag with depth. Finally, uz is calculated from the amplitude damping. After having tested this approach with synthetic data, we used the 1984-2001 Abbeville (Somme, France) data to determine the average recharge over six 3-year periods. The results are in good agreement with classical meteorological recharge estimates and show a significant increase in the recharge during the last 3-year period, consistent with the observed phreatic 2001 flood event. Specific temperature measurements at appropriate depths and time steps could drastically improve the sensitivity of the method.

  4. Bioremediation of contaminated groundwater

    DOEpatents

    Hazen, Terry C.; Fliermans, Carl B.

    1995-01-01

    An apparatus and method for in situ remediation of contaminated subsurface soil or groundwater contaminated by chlorinated hydrocarbons. A nutrient fluid is selected to stimulate the growth and reproduction of indigenous subsurface microorganisms that are capable of degrading the contaminants; an oxygenated fluid is selected to create a generally aerobic environment for these microorganisms to degrade the contaminants, leaving only pockets that are anaerobic. The nutrient fluid is injected periodically while the oxygenated fluid is injected continuously and both are extracted so that both are drawn across the plume. The nutrient fluid stimulates microbial colony growth; withholding it periodicially forces the larger, healthy colony of microbes to degrade the contaminants. Treatment is continued until the subsurface concentration of contaminants is reduced to an acceptable, preselected level. The nutrient fluid can be methane and the oxygenated fluid air for stimulating production of methanotrophs to break down chlorohydrocarbons, especially trichloroethylene (TCE) and tetrachloroethylene.

  5. Bioremediation of contaminated groundwater

    DOEpatents

    Hazen, T.C.; Fliermans, C.B.

    1995-01-24

    An apparatus and method are described for in situ remediation of contaminated subsurface soil or groundwater contaminated by chlorinated hydrocarbons. A nutrient fluid is selected to stimulate the growth and reproduction of indigenous subsurface microorganisms that are capable of degrading the contaminants. An oxygenated fluid is selected to create a generally aerobic environment for these microorganisms to degrade the contaminants, leaving only pockets that are anaerobic. The nutrient fluid is injected periodically while the oxygenated fluid is injected continuously and both are extracted so that both are drawn across the plume. The nutrient fluid stimulates microbial colony growth. Withholding it periodically forces the larger, healthy colony of microbes to degrade the contaminants. Treatment is continued until the subsurface concentration of contaminants is reduced to an acceptable, preselected level. The nutrient fluid can be methane and the oxygenated fluid air for stimulating production of methanotrophs to break down chlorohydrocarbons, especially trichloroethylene (TCE) and tetrachloroethylene. 3 figures.

  6. Bioremediation of contaminated groundwater

    DOEpatents

    Hazen, T.C.; Fliermans, C.B.

    1994-01-01

    Disclosed is an apparatus and method for in situ remediation of contaminated subsurface soil or groundwater contaminated by chlorinated hydrocarbons. A nutrient fluid (NF) is selected to simulated the growth and reproduction of indigenous subsurface microorganisms capable of degrading the contaminants; an oxygenated fluid (OF) is selected to create an aerobic environment with anaerobic pockets. NF is injected periodically while OF is injected continuously and both are extracted so that both are drawn across the plume. NF stimulates microbial colony growth; withholding it periodically forces the larger, healthy colony of microbes to degrade the contaminants. Treatment is continued until the subsurface concentration of contaminants is acceptable. NF can be methane and OF be air, for stimulating production of methanotrophs to break down chlorohydrocarbons, especially TCE and tetrachloroethylene.

  7. Quantification and modelling of water flow in rain-fed paddy fields in NE Thailand: Evidence of soil salinization under submerged conditions by artesian groundwater

    NASA Astrophysics Data System (ADS)

    Hammecker, Claude; Maeght, Jean-Luc; Grünberger, Olivier; Siltacho, Siwaporn; Srisruk, Kriengsak; Noble, Andrew

    2012-08-01

    SummaryWater flow and solute transport in soils forms an essential part in many groundwater hydrology studies. This is especially true for Northeast Thailand, where the agricultural land is affected by the soil salinity, which is a widespread and an increasing phenomenon affecting 25% of the agricultural land. Salinization appears as scattered discrete patches of 10-100 m2 in the lowlands, illustrated by white efflorescences during the dry season and bare soil during the cropping season. A field study was undertaken in farm plots to measure the water flow and solute transport within the soil surface and the vadose zone, both inside and outside a saline patch. The water flow was measured on the soil surface with lysimeters and infiltration rings, and was derived in the soil from the hydraulic gradients measured with tensiometers placed at different depths. The salt transport was evaluated with water traps also placed at different depths, where the soil water's electrical conductivity was measured throughout the rainy season. Field study results demonstrated that the accumulation of saline solutions in rain fed paddy fields, occurred mainly during the rainy season while the soil surface remained flooded. During this period the saline water table rose towards the soil surface independently of infiltration into the soil. It happened in specific places where the compacted soil layer, generally ubiquitous in the area at a depth of 40-50 cm, is interrupted. Therefore salinity appeareds in discret points as patches. Artesian upward flow already described in this area (Haworth et al., 1966; Williamson et al., 1989; Imaizumi et al., 2002) is most probably responsible for this water table rise, thereby affecting crop productivity. Numerical modelling of water flow using HYDRUS-3D further supported these results and showed that managing the depth of flooding within the plot can significantly reduce the outbreak of these saline plumes.

  8. AirMOSS P-Band Radar Retrieval of Subcanopy Soil Moisture Profile

    NASA Astrophysics Data System (ADS)

    Tabatabaeenejad, A.; Burgin, M. S.; Duan, X.; Moghaddam, M.

    2013-12-01

    Knowledge of soil moisture, as a key variable of the Earth system, plays an important role in our under-standing of the global water, energy, and carbon cycles. The importance of such knowledge has led NASA to fund missions such as Soil Moisture Active and Passive (SMAP) and Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS). The AirMOSS mission seeks to improve the estimates of the North American Net Ecosystem Exchange (NEE) by providing high-resolution observations of the root zone soil moisture (RZSM) over regions representative of the major North American biomes. AirMOSS flies a P-band SAR to penetrate vegetation and into the root zone to provide estimates of RZSM. The flights cover areas containing flux tower sites in regions from the boreal forests in Saskatchewan, Canada, to the tropical forests in La Selva, Costa Rica. The radar snapshots are used to generate estimates of RZSM via inversion of a scattering model of vegetation overlying soils with variable moisture profiles. These retrievals will be used to generate a time record of RZSM, which will be integrated with an ecosystem demography model in order to estimate the respiration and photosynthesis carbon fluxes. The aim of this work is the retrieval of the moisture profile over AirMOSS sites using the collected P-band radar data. We have integrated layered-soil scattering models into a forest scattering model; for the backscattering from ground and for the trunk-ground double-bounce mechanism, we have used a layered small perturbation method and a coherent scattering model of layered soil, respectively. To estimate the soil moisture profile, we represent it as a second-order polynomial in the form of az2 + bz + c, where z is the depth and a, b, and c are the coefficients to be retrieved from radar measurements. When retrieved, these coefficients give us the soil moisture up to a prescribed depth of validity. To estimate the unknown coefficients of the polynomial, we use simulated

  9. Groundwater-soil moisture-climate interactions: lessons from idealized model experiments with forced water table depth

    NASA Astrophysics Data System (ADS)

    Ducharne, Agnès; Lo, Min-Hui; Decharme, Bertrand; Wang, Fuxing; Cheruy, Frédérique; Ghattas, Josefine; Chien, Rong-You; lan, Chia-Wei; Colin, Jeanne; Tyteca, Sophie

    2016-04-01

    Groundwater (GW) constitutes by far the largest volume of liquid freshwater on Earth. The most active part is soil moisture (SM), recognized as a key variable of land/atmosphere interactions, especially in so-called transition zones, where/when SM varies between wet and dry values. But GW can also be stored in deeper reservoirs than soils, in particular unconfined aquifer systems, in which the saturated part is called the water table (WT). The latter is characterized by slow and mostly horizontal water flows towards the river network, with well-known buffering effects on streamflow variability. Where/when the WT is shallow enough, it can also sustain SM by means of capillary rise, thus increase evapotranspiration (ET), with potential impact on the climate system (including temperatures and precipitation). The large residence time of GW may also increase the Earth system's memory, with consequences on the persistence of extreme events, hydro-climatic predictability, and anthropogenic climate change, particularly the magnitude of regional warming. Here, our main goal is to explore the potential impacts of the water table depth (WTD) on historical climate through idealized model analyses. To this end, we force three state-of-the art land surface models (LSMs), namely CLM, ORCHIDEE, and SURFEX, with prescribed WTDs ranging from 0.5 to 10 m. The LSMs are run either off-line or coupled to their parent climate model, following LMIP/AMIP-like protocols for intercomparability. Within this framework, we want to assess the sensitivity of ET and the simulated climate to the WTD in a systematic way. In particular, we will identify and compare the patterns of the critical WTD, defined as the deepest one to achieve a significant change in ET. To this end, we estimate derivatives of ET with respect to WTD, which tell how the sensitivity of ET to a unit change in WTD evolves with WTD. In each grid-point, these derivatives can be used to define the critical WTD, given a threshold ET

  10. Groundwater pollution microbiology

    SciTech Connect

    Bitton, G.; Gerba, C.P.

    1984-01-01

    This book provides a survey of available information on groundwater pollution microbiology. It is useful as a starting point for students and professionals investigating this topic. Subjects discussed include bacteria and virus movement through soils, carcinogenicity of some organic chemicals detected in groundwater, sampling techniques, and land treatment systems. Include references to the journal literature and a subject index.

  11. Reliable test methods for the determination of a natural production of chloroform in soils.

    PubMed

    Grøn, Christian; Laturnus, Frank; Jacobsen, Ole Stig

    2012-03-01

    Chloroform is one of the most frequently found anthropogenic groundwater contaminants. Recent investigations, however, suggested that chloroform in groundwater may also originate from a natural production in soils. As societies response to the occurrence of chloroform in groundwater may depend upon its origin as anthropogenic or naturally produced, test methods are needed to measure the potential of natural soil chloroform production. Field measurements of ambient air and soil air, and field and laboratory incubation studies were evaluated for measurement of relative soil chloroform production at a site with four different vegetation types (spruce forest, beech forest, grassland, and grain field) on comparable geological soil. All test methods showed varying soil production of chloroform with spruce forest soil being most productive and grain field soil being least productive. Field measurements of the ratio of soil air to ambient air chloroform concentrations exhibited the smallest difference between high production and low production areas, whereas laboratory incubation studies showed the largest difference. Thus, laboratory incubation studies are suggested as most efficient for estimating relative chloroform production in soil. The study indicated that soil samples should be tested not more than 14 days after sampling. Furthermore, it was found that potentially limiting compounds, such as chloride or nitrate, are not needed to be added in spike experiments to obtain reliable production results. However, it should be recognized that the processes of soil chloroform production are not known yet in all details. Other factors than those studied here may affect the test methods for soil chloroform production too.

  12. Ground-water hydrology and water quality of the southern high plains aquifer, Melrose Air Force Range, Cannon Air Force Base, Curry and Roosevelt Counties, New Mexico, 2002-03

    USGS Publications Warehouse

    Langman, Jeff B.; Gebhardt, Fredrick E.; Falk, Sarah E.

    2004-01-01

    In cooperation with the U.S. Air Force, the U.S. Geological Survey characterized the ground-water hydrology and water quality at Melrose Air Force Range in east-central New Mexico. The purpose of the study was to provide baseline data to Cannon Air Force Base resource managers to make informed decisions concerning actions that may affect the ground-water system. Five periods of water-level measurements and four periods of water-quality sample collection were completed at Melrose Air Force Range during 2002 and 2003. The water-level measurements and water-quality samples were collected from a 29-well monitoring network that included wells in the Impact Area and leased lands of Melrose Air Force Range managed by Cannon Air Force Base personnel. The purpose of this report is to provide a broad overview of ground-water flow and ground-water quality in the Southern High Plains aquifer in the Ogallala Formation at Melrose Air Force Range. Results of the ground-water characterization of the Southern High Plains aquifer indicated a local flow system in the unconfined aquifer flowing northeastward from a topographic high, the Mesa (located in the southwestern part of the Range), toward a regional flow system in the unconfined aquifer that flows sout