Sample records for groundwater contamination sources

  1. Boron isotope application for tracing sources of contamination in groundwater.

    E-print Network

    Kasher, Roni

    Boron isotope application for tracing sources of contamination in groundwater. Abstract: Boron isotope composition and concentration of sewage effluent and pristine and contaminated groundwater from. Anthropogenic boron in wastewater is isotopically distinct from natural boron in groundwater and thus can

  2. Groundwater Contamination

    NSDL National Science Digital Library

    Matthew Babcock

    This site by the Michigan Environmental Education Curriculum presents an interactive module that provides an introduction to groundwater quality issues. The information is presented as a series of slides with text, animations, quiz questions and interactive features. Topics include types of aquifers, groundwater movement, sources of contamination, the concentration and dispersion of contaminants, plumes and remediation.

  3. Groundwater Contamination

    NSDL National Science Digital Library

    The Groundwater Foundation's sources of ground water contamination page discusses common contaminates, how they get to ground water, sources of pollution along with cleanup and prevention practices. The site's focal point is a detailed map of contaminants as they enter the water cycle.

  4. Areal identification of groundwater nitrate contamination sources in periurban areas

    Microsoft Academic Search

    Alfonso Corniello; Daniela Ducci; Giovanni Ruggieri

    2007-01-01

    Background, Aims and Scope  The purpose of this study is to verify a method for groundwater contamination risk assessment in urban and periurban areas\\u000a using Geographic Information Systems (GIS). The method is based on agricultural hazard evaluation. In urban and periurban\\u000a areas, the problem of dealing with NO3 concentrations mainly entails identifying nitrate sources from the excessive use of fertilizers, or

  5. Groundwater Contamination

    NSDL National Science Digital Library

    Christine McLelland

    This lesson addresses groundwater contamination from leakage of underground gasoline, oil, or other hazardous chemical tanks. Students read two short articles and investigate causes, effects, solutions, and prevention measures.

  6. Groundwater Contamination

    NSDL National Science Digital Library

    Carl Van Faasen

    2009-04-01

    This investigation consists of two parts, in which students first model the effects of groundwater contamination and then track the flow of the contamination. However, Part I does not have to be done in order to do Part II. This Teacher Information sectio

  7. Toxic fluoride and arsenic contaminated groundwater in the Lahore and Kasur districts, Punjab, Pakistan and possible contaminant sources

    Microsoft Academic Search

    Abida Farooqi; Harue Masuda; Nousheen Firdous

    2007-01-01

    The present study is the first attempt to put forward possible sources of As, F? and SO42? contaminated groundwater in the Kalalanwala area, Punjab, Pakistan. Five rainwater and 24 groundwater samples from three different depths were analyzed. Shallow groundwater from 24 to 27m depth contained high F? (2.47–21.1mg\\/L), while the groundwater samples from the deeper depth were free from fluoride

  8. Emerging organic contaminants in groundwater: A review of sources, fate and occurrence.

    PubMed

    Lapworth, D J; Baran, N; Stuart, M E; Ward, R S

    2012-04-01

    Emerging organic contaminants (EOCs) detected in groundwater may have adverse effects on human health and aquatic ecosystems. This paper reviews the existing occurrence data in groundwater for a range of EOCs including pharmaceutical, personal care, 'life-style' and selected industrial compounds. The main sources and pathways for organic EOCs in groundwater are reviewed, with occurrence data for EOCs in groundwater included from both targeted studies and broad reconnaissance surveys. Nanogram-microgram per litre concentrations are present in groundwater for a large range of EOCs as well as metabolites and transformation products and under certain conditions may pose a threat to freshwater bodies for decades due to relatively long groundwater residence times. In the coming decades, more of these EOCs are likely to have drinking water standards, environmental quality standards and/or groundwater threshold values defined, and therefore a better understanding of the spatial and temporal variation remains a priority. PMID:22306910

  9. Development of a microbial contamination susceptibility model for private domestic groundwater sources

    NASA Astrophysics Data System (ADS)

    Hynds, Paul D.; Misstear, Bruce D.; Gill, Laurence W.

    2012-12-01

    Groundwater quality analyses were carried out on samples from 262 private sources in the Republic of Ireland during the period from April 2008 to November 2010, with microbial quality assessed by thermotolerant coliform (TTC) presence. Assessment of potential microbial contamination risk factors was undertaken at all sources, and local meteorological data were also acquired. Overall, 28.9% of wells tested positive for TTC, with risk analysis indicating that source type (i.e., borehole or hand-dug well), local bedrock type, local subsoil type, groundwater vulnerability, septic tank setback distance, and 48 h antecedent precipitation were all significantly associated with TTC presence (p < 0.05). A number of source-specific design parameters were also significantly associated with bacterial presence. Hierarchical logistic regression with stepwise parameter entry was used to develop a private well susceptibility model, with the final model exhibiting a mean predictive accuracy of >80% (TTC present or absent) when compared to an independent validation data set. Model hierarchies of primary significance are source design (20%), septic tank location (11%), hydrogeological setting (10%), and antecedent 120 h precipitation (2%). Sensitivity analysis shows that the probability of contamination is highly sensitive to septic tank setback distance, with probability increasing linearly with decreases in setback distance. Likewise, contamination probability was shown to increase with increasing antecedent precipitation. Results show that while groundwater vulnerability category is a useful indicator of aquifer susceptibility to contamination, its suitability with regard to source contamination is less clear. The final model illustrates that both localized (well-specific) and generalized (aquifer-specific) contamination mechanisms are involved in contamination events, with localized bypass mechanisms dominant. The susceptibility model developed here could be employed in the appropriate location, design, construction, and operation of private groundwater wells, thereby decreasing the contamination risk, and hence health risk, associated with these sources.

  10. Ground-water contaminant plume differentiation and source determination using BTEX concentration ratios

    Microsoft Academic Search

    Y. Jeffrey Yang; Rick D. Spencer; Mark A. Mersmann; Todd M. Gates

    1995-01-01

    Concentration ratios of benzene, toluene, ethylbenzene, and xylenes (BTEX) in ground water can be used for ground-water contaminant plume differentiation and source determination. Computer modeling utilizing BTEX soil-water partitioning coefficients and biodegradation rates shows that hydraulic dispersion, retardation, and biodegradation do not significantly modify the BTEX concentration ratios in ground water, particularly those of ethylbenzene and xylenes. Therefore, the BTEX

  11. Fingerprinting groundwater pollution in catchments with contrasting contaminant sources using microorganic compounds.

    PubMed

    Stuart, Marianne E; Lapworth, Dan J; Thomas, Jenny; Edwards, Laura

    2014-01-15

    Evaluating the occurrence of microorganics helps to understand sources and processes which may be controlling the transport and fate of emerging contaminants (ECs). A study was carried out at the contrasting instrumented environmental observatory sites at Oxford, on the peri-urban floodplain gravel aquifer of the River Thames and Boxford, in the rural valley of the River Lambourn on the chalk aquifer, in Southern England to explore the use of ECs to fingerprint contaminant sources and flow pathways in groundwater. At Oxford compounds were typical of a local waste tip plume (not only plasticisers and solvents but also barbiturates and N,N-diethyl-m-toluamide (DEET)) and of the urban area (plasticisers and mood-enhancing drugs such as carbamazepine). At Boxford the results were different with widespread occurrence of agricultural pesticides, their metabolites and the solvent trichloroethene, as well as plasticisers, caffeine, butylated food additives, DEET, parabens and trace polyaromatic hydrocarbons (PAHs). Groups of compounds used in pharmaceuticals and personal care products of different provenance in the environment could be distinguished, i) historical household and medical waste, ii) long-term household usage persistent in groundwater and iii) current usage and contamination from surface water. Co-contaminant and degradation products can also indicate the likely source of contaminants. A cocktail of contaminants can be used as tracers to provide information on catchment pathways and groundwater/surface water interactions. A prominent feature in this study is the attenuation of many EC compounds in the hyporheic zone. PMID:24055671

  12. Groundwater Contamination in Urban Areas

    Microsoft Academic Search

    Keisuke Kuroda; Tetsuo Fukushi

    Groundwater has been used everywhere in the world for a long time because of its easy accessibility and good quality. In urban\\u000a areas, groundwater as a source of domestic, commercial and industrial water has greatly contributed to the development of\\u000a cities. Groundwater in urban areas is sometimes contaminated with multiple contaminants at higher concentrations than in rural\\u000a areas. For example,

  13. The Relationship Between Partial Contaminant Source Zone Remediation and Groundwater Plume Attenuation

    NASA Astrophysics Data System (ADS)

    Falta, R. W.

    2004-05-01

    Analytical solutions are developed that relate changes in the contaminant mass in a source area to the behavior of biologically reactive dissolved contaminant groundwater plumes. Based on data from field experiments, laboratory experiments, numerical streamtube models, and numerical multiphase flow models, the chemical discharge from a source region is assumed to be a nonlinear power function of the fraction of contaminant mass removed from the source zone. This function can approximately represent source zone mass discharge behavior over a wide range of site conditions ranging from simple homogeneous systems, to complex heterogeneous systems. A mass balance on the source zone with advective transport and first order decay leads to a nonlinear differential equation that is solved analytically to provide a prediction of the time-dependent contaminant mass discharge leaving the source zone. The solution for source zone mass discharge is coupled semi-analytically with a modified version of the Domenico (1987) analytical solution for three-dimensional reactive advective and dispersive transport in groundwater. The semi-analytical model then employs the BIOCHLOR (Aziz et al., 2000; Sun et al., 1999) transformations to model sequential first order parent-daughter biological decay reactions of chlorinated ethenes and ethanes in the groundwater plume. The resulting semi-analytic model thus allows for transient simulation of complex source zone behavior that is fully coupled to a dissolved contaminant plume undergoing sequential biological reactions. Analyses of several realistic scenarios show that substantial changes in the ground water plume can result from the partial removal of contaminant mass from the source zone. These results, however, are sensitive to the nature of the source mass reduction-source discharge reduction curve, and to the rates of degradation of the primary contaminant and its daughter products in the ground water plume. Aziz, C.E., C.J. Newell, J.R. Gonzales, P. Haas, T.P. Clement, and Y. Sun, 2000, BIOCHLOR Natural Attenuation Decision Support System User's Manual Version 1.0, US EPA Report EPA/600/R-00/008 Domenico, P.A., 1987, An analytical model for multidimensional transport of a decaying contaminant species, J. Hydrol., 91: 49-58. Sun, Y., J.N. Petersen, T.P. Clement, and R.S. Skeen, 1999, A new analytical solution for multi-species transport equations with serial and parallel reactions, Water Resour. Res., 35(1): 185-190.

  14. A new mathematical technique for identifying potential sources of groundwater contamination

    Microsoft Academic Search

    W. R. Laton; R. J. Whitley; T. V. Hromadka

    2007-01-01

    The observed hydrogeochemical condition of groundwater at a particular well is usually represented as a mixture of various\\u000a sources of pollution and background conditions and is given in terms of measurements of multiple dissolved inorganic water\\u000a contaminants such as total dissolved solids (TDS). Concentrations from a given set of wells can be compared against one another\\u000a in a variety of

  15. A spatial analysis of pit latrine density and groundwater source contamination.

    PubMed

    Wright, Jim A; Cronin, Aidan; Okotto-Okotto, Joseph; Yang, Hong; Pedley, Steve; Gundry, Stephen W

    2013-05-01

    This study aims to assess the relationship between chemical and microbial contamination of groundwater sources and a range of potential hazards in two peri-urban areas of Kisumu, Kenya where shallow wells and pit latrines are widely used. From 1998 to 2004, 263 samples were taken from 61 groundwater sources and tested for thermotolerant coliforms. Eighteen of these sources were also tested for chemical contaminants, including nitrate, chloride and fluoride. The locations of all water sources, buildings and pit latrines in the study area were surveyed. Local pit latrine densities were calculated using a geographic information system. Ten out 18 samples were above the World Health Organization guideline values for nitrate, 236 out of 263 were positive for thermotolerant coliforms, and all were above the guideline values for fluoride. There was neither a relationship between thermotolerant coliform levels and daily rainfall patterns nor with sanitary risk inspection scores for samples from shallow wells (r = 0.01, p = 0.91, n = 191). The density of pit latrines within a 100-m radius was significantly correlated with nitrate and chloride levels (r = 0.64, p = 0.004 and r = 0.46, p = 0.05, respectively) but not with thermotolerant coliforms (r = 0.22, p = 0.11). These results illustrate both the public health risks associated with shallow groundwater sources, on-site sanitation and high population density. These findings have implications for current policies that promote latrine construction, especially in peri-urban areas of high population density. More comprehensive studies of larger communities should be commissioned to extend this analysis of the links between latrine density and groundwater contamination and so identify the contingent policy risks. PMID:22976120

  16. Groundwater nitrate contamination and use of Cl/Br ratio for source appointment.

    PubMed

    Samantara, M K; Padhi, R K; Satpathy, K K; Sowmya, M; Kumaran, P

    2015-02-01

    Source appointment for groundwater nitrate contamination is critical in prioritizing effective strategy for its mitigation. Here, we assessed the use of Cl/Br ratio and statistical correlation of hydro-chemical parameters to identify the nitrate source to the groundwater. A total of 228 samples from 19 domestic wells distributed throughout the study area were collected during June 2011-May 2012 and analyzed for various physicochemical parameters. Study area was divided into three spatial zones based on demographic features, viz., northern, southern, and central part. Nitrate concentration in 57 % of samples exceeded the prescribed safe limit for drinking stipulated by the World Health Organization (WHO) and Bureau of Indian standards (BIS). The central part of the study area showed elevated nitrate concentration ranging from below detection limit (BDL) to 263.5 mg/l as NO3 (-) and demonstrated high attenuation within the immediate vicinity thereby restricting diffusion of the nitrate to the adjacent parts. Resolution of correlation matrix as statistical indicator for nitrate contamination was poor. Seventy-seven percent of samples with high nitrate concentration (>45 mg/l as NO3 (-)) showed strong association with high Cl/Br mass ratio (350-900), indicating mixing of sewage and septic tank effluents with groundwater as a primary source for the nitrate in the studied area. Nitrate level during monsoon (BDL, 229.9 mg/l as NO3 (-)), post-monsoon (BDL, 263.5 mg/l as NO3 (-)), and pre-monsoon (0.5-223.1 mg/l as NO3 (-)) indicated additional contribution of surface leaching to groundwater. PMID:25638054

  17. Cost-benefit analysis of cosolvent flushing to treat groundwater contamination source areas

    SciTech Connect

    Anason, S.L.

    1999-03-01

    Dense non-aqueous phase liquids (DNAPLs) in the zone beneath the water table can be a virtually permanent source of groundwater contamination that cannot be remediated by currently available technologies. Cosolvent flushing is a new technology that has the potential to remediate these sites and could pose a solution to the problem of DNAPL source areas. A computer model was developed to determine the cost and time to remediate an aquifer using cosolvent flushing. Included in the model is a module to calculate the costs of recycling the alcohol that is used as the cosolvent. The model was validated using site conditions to a prior study. It was determined that recycling the cosolvent allows cosolvent flushing to be a cost effective alternative to surfactant flushing, another new technology being considered for DNAPL source remediation. Sensitivity analysis of the model was conducted by varying the saturation percentage of contaminant, percentage and type of alcohol used in the cosolvent mixture, site hydraulic conductivity, and the contaminant. Five alcohols were modeled: methanol, ethanol, 1-isopropanol, 2-isopropanol, and tert-butyl-alcohol (TBA). 1-Isopropanol, 2-isopropanol, and TBA were always more expensive than methanol and ethanol.

  18. Source-identification investigations of petroleum contaminated groundwater in the Missouri Ozarks

    Microsoft Academic Search

    James B. Fels

    1999-01-01

    The growing population in the Missouri Ozarks rely on the abundant supply of potable groundwater found in the fractured bedrock underlying the region. Protection of this valuable resource from surface, or near-surface contamination is essential to the health and safety of the citizens of Missouri. Petroleum products stored in underground storage tanks pose a threat to groundwater if a release

  19. Groundwater contamination from stormwater infiltration

    SciTech Connect

    Pitt, R.; Clark, S.; Parmer, K. [Univ. of Alabama, Birmingham, AL (United States)] [and others

    1995-10-01

    The research summarized here was conducted during the first year of a 3-yr cooperative agreement (CR819573) to identify and control stormwater toxicants, especially those adversely affecting groundwater. The purpose of this research effort was to review the groundwater contamination literature as it relates to stormwater. Prior to urbanization groundwater is recharged by rainfall-runoff and snowmelt infiltrating through pervious surfaces including grasslands and woods. This infiltrating water is relatively uncontaminated. Urbanization, however, reduces the permeable soil surface area through which recharge by infiltration occurs. This results in much less groundwater recharge and greatly increased surface runoff. In addition the waters available for recharge carry increased quantities of pollutants. With urbanization, waters having elevated contaminant concentrations also recharge groundwater including effluent from domestic septic tanks, wastewater from percolation basins and industrial waste injection wells, infiltrating stormwater, and infiltrating water from agricultural irrigation. The areas of main concern that are covered by this paper are: the source of the pollutants, stormwater constituents having a high potential to contaminate groundwater, and the treatment necessary for stormwater.

  20. Bioremediation of contaminated groundwater

    DOEpatents

    Hazen, Terry C. (Augusta, GA); Fliermans, Carl B. (Augusta, GA)

    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.

  1. 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.

  2. Identification of the nitrate contamination sources of the Brusselian sands groundwater body (Belgium) using a dual-isotope approach

    NASA Astrophysics Data System (ADS)

    Mattern, Samuel; Vanclooster, Marnik

    2010-05-01

    Knowledge of the groundwater pollution source is of primary importance to define appropriate remediation strategies. Yet, the identification of the contamination sources remains a complicated task. A dual isotope approach has been used to provide information for tracing sources of nitrate in water. In this study, we used the naturally occurring stable isotopic composition of groundwater nitrate (1) to evaluate the origin of nitrate in the Brussels sands aquifer (Belgium) and (2) to study the temporal dynamics of the isotope signature of groundwater nitrate in this region. Potential N sources sampled in the region, including e.g. ammonium and nitrate mineral fertilizers, sewage and rain, had isotopic signatures that fell within the corresponding typical ranges found in literature. Some of them however deviated from the isotopic ranges corresponding to typical N sources, illustrating the impact of processes affecting the isotopic signature of the nitrate sources. During a pluri-annual sampling campaign, groundwater samples were collected at 10 moments between June 2007 and February of 2009 over 9 monitoring stations located in the western part of the study area. The isotopic data time series suggest that, most of the time, N applied on the soil has been cycled in the soil by micro-organisms before leaching to the groundwater, while the isotopic data and the high nitrate concentrations strongly suggests that nitrate of the groundwater sampled in January 2008 principally originates from mineral fertilizers. The isotopic data measured at some of the 114 monitoring stations across the study area strongly suggests that the sources of nitrate are mineral fertilizers used in agriculture and golf courses, manure leaching from unprotected stockpiles in farms, domestic gardening practices, cesspools and probably cemeteries. Isotopic data are particularly helpful when associated with other information like historical data about monitoring stations, land use, chemical parameters of water or statistical and deterministic models and must therefore be considered as one of the many elements of pollution sources identification.

  3. Sources, pathways, and relative risks of contaminants in surface water and groundwater: a perspective prepared for the Walkerton inquiry.

    PubMed

    Ritter, Len; Solomon, Keith; Sibley, Paul; Hall, Ken; Keen, Patricia; Mattu, Gevan; Linton, Beth

    2002-01-11

    On a global scale, pathogenic contamination of drinking water poses the most significant health risk to humans, and there have been countless numbers of disease outbreaks and poisonings throughout history resulting from exposure to untreated or poorly treated drinking water. However, significant risks to human health may also result from exposure to nonpathogenic, toxic contaminants that are often globally ubiquitous in waters from which drinking water is derived. With this latter point in mind, the objective of this commission paper is to discuss the primary sources of toxic contaminants in surface waters and groundwater, the pathways through which they move in aquatic environments, factors that affect their concentration and structure along the many transport flow paths, and the relative risks that these contaminants pose to human and environmental health. In assessing the relative risk of toxic contaminants in drinking water to humans, we have organized our discussion to follow the classical risk assessment paradigm, with emphasis placed on risk characterization. In doing so, we have focused predominantly on toxic contaminants that have had a demonstrated or potential effect on human health via exposure through drinking water. In the risk assessment process, understanding the sources and pathways for contaminants in the environment is a crucial step in addressing (and reducing) uncertainty associated with estimating the likelihood of exposure to contaminants in drinking water. More importantly, understanding the sources and pathways of contaminants strengthens our ability to quantify effects through accurate measurement and testing, or to predict the likelihood of effects based on empirical models. Understanding the sources, fate, and concentrations of chemicals in water, in conjunction with assessment of effects, not only forms the basis of risk characterization, but also provides critical information required to render decisions regarding regulatory initiatives, remediation, monitoring, and management. Our discussion is divided into two primary themes. First we discuss the major sources of contaminants from anthropogenic activities to aquatic surface and groundwater and the pathways along which these contaminants move to become incorporated into drinking water supplies. Second, we assess the health significance of the contaminants reported and identify uncertainties associated with exposures and potential effects. Loading of contaminants to surface waters, groundwater, sediments, and drinking water occurs via two primary routes: (1) point-source pollution and (2) non-point-source pollution. Point-source pollution originates from discrete sources whose inputs into aquatic systems can often be defined in a spatially explicit manner. Examples of point-source pollution include industrial effluents (pulp and paper mills, steel plants, food processing plants), municipal sewage treatment plants and combined sewage-storm-water overflows, resource extraction (mining), and land disposal sites (landfill sites, industrial impoundments). Non-point-source pollution, in contrast, originates from poorly defined, diffuse sources that typically occur over broad geographical scales. Examples of non-point-source pollution include agricultural runoff (pesticides, pathogens, and fertilizers), storm-water and urban runoff, and atmospheric deposition (wet and dry deposition of persistent organic pollutants such as polychlorinated biphenyls [PCBs] and mercury). Within each source, we identify the most important contaminants that have either been demonstrated to pose significant risks to human health and/or aquatic ecosystem integrity, or which are suspected of posing such risks. Examples include nutrients, metals, pesticides, persistent organic pollutants (POPs), chlorination by-products, and pharmaceuticals. Due to the significant number of toxic contaminants in the environment, we have necessarily restricted our discussion to those chemicals that pose risks to human health via exposure through drinking water. A comprehensive and judicious

  4. Identifying sources of groundwater nitrate contamination in a large alluvial groundwater basin with highly diversified intensive agricultural production.

    PubMed

    Lockhart, K M; King, A M; Harter, T

    2013-08-01

    Groundwater quality is a concern in alluvial aquifers underlying agricultural areas worldwide. Nitrate from land applied fertilizers or from animal waste can leach to groundwater and contaminate drinking water resources. The San Joaquin Valley, California, is an example of an agricultural landscape with a large diversity of field, vegetable, tree, nut, and citrus crops, but also confined animal feeding operations (CAFOs, here mostly dairies) that generate, store, and land apply large amounts of liquid manure. As in other such regions around the world, the rural population in the San Joaquin Valley relies almost exclusively on shallow domestic wells (?150 m deep), of which many have been affected by nitrate. Variability in crops, soil type, and depth to groundwater contribute to large variability in nitrate occurrence across the underlying aquifer system. The role of these factors in controlling groundwater nitrate contamination levels is examined. Two hundred domestic wells were sampled in two sub-regions of the San Joaquin Valley, Stanislaus and Merced (Stan/Mer) and Tulare and Kings (Tul/Kings) Counties. Forty six percent of well water samples in Tul/Kings and 42% of well water samples in Stan/Mer exceeded the MCL for nitrate (10mg/L NO3-N). For statistical analysis of nitrate contamination, 78 crop and landuse types were considered by grouping them into ten categories (CAFO, citrus, deciduous fruits and nuts, field crops, forage, native, pasture, truck crops, urban, and vineyards). Vadose zone thickness, soil type, well construction information, well proximity to dairies, and dominant landuse near the well were considered. In the Stan/Mer area, elevated nitrate levels in domestic wells most strongly correlate with the combination of very shallow (?21 m) water table and the presence of either CAFO derived animal waste applications or deciduous fruit and nut crops (synthetic fertilizer applications). In Tulare County, statistical data indicate that elevated nitrate levels in domestic well water are most strongly associated with citrus orchards when located in areas with a very shallow (?21 m) water table. Kings County had relatively few nitrate MCL exceedances in domestic wells, probably due to the deeper water table in Kings County. PMID:23800783

  5. Identification of sources and behavior of agricultural contaminants in groundwater using nitorgen and sulfur isootope in Haean basin, Korea

    NASA Astrophysics Data System (ADS)

    Kaown, Dugin; Kim, Heejung; Mayer, Bernard; Hyun, Yunjung; Lee, Jin-Yong; Lee, Kang-Kun

    2013-04-01

    The Haean basin shows a bowl-shaped topographic feature and the drainage system shows a dendritic pattern. The study area is consisted of forests (58.0%), vegetable fields (27.6%), rice paddy fields (11.4%) and fruit fields (0.5%). Most of residents in the study area practice agriculture and paddy rice and vegetables (Chinese radish) are the typical crops grown. The concentration of nitrate in groundwater showed 0.8 ~ 67.3 mg/L in June, 2012 and 2.0 ~ 65.7 mg/L in September, 2012. Hydrogeochemical values and stable isotope ratios of dissolved nitrate and sulfate in groundwater were used to identify contamination sources and transformation processes in shallow groundwater. The ?15N-NO3- values in the study area ranged between +5.2 and +16.9‰ in June and between +4.4 and +13.0‰ in September. The sulfate concentration in groundwater samples obtained from the study area varied from 0.8 to 16.5 mg/L in June and 0 to 19.7 mg/L in September. ?34S-SO42- values ranged from +2.9 to +11.7‰ in June and +1.6 to +8.2‰ in September. The values of ?15N-NO3- and ?34S-SO42- in September were slightly decreased than those of values in June. The chemical composition of groundwater in vegetable and fruit fields showed slightly lower values of ?34S-SO42- and ?15N-NO3- indicated that a mixture of synthetic and organic fertilizers is responsible for groundwater contamination with agro-chemicals. Most groundwater from forests and paddy fields showed slightly higher values of ?15N-NO3- suggested that organic fertilizer is introduced into subsurface.

  6. Costs of groundwater contamination

    SciTech Connect

    O'Neil, W.B.; Raucher, R.S. (Environmental Protection Agency, Washington, DC (United States))

    1990-01-01

    Two factors determine the cost of groundwater contamination: (1) the ways in which water was being used or was expected to be used in the future and (2) the physical characteristics of the setting that constrain the responses available to regain lost uses or to prevent related damages to human health and the environment. Most contamination incidents can be managed at a low enough cost that uses will not be foreclosed. It is important to take into account the following when considering costs: (1) natural cleansing through recharge and dilution can take many years; (2) it is difficult and costly to identify the exact area and expected path of a contamination plume; and (3) treatment or replacement of contaminated water often may represent the cost-effective strategy for managing the event. The costs of contamination include adverse health effects, containment and remediation, treatment and replacement costs. In comparing the costs and benefits of prevention programs with those of remediation, replacement or treatment, it is essential to adjust the cost/benefit numbers by the probability of their actual occurrence. Better forecasts of water demand are needed to predict more accurately the scarcity of new supply and the associated cost of replacement. This research should include estimates of the price elasticity of water demand and the possible effect on demand of more rational cost-based pricing structures. Research and development of techniques for in situ remediation should be encouraged.

  7. Solutions Remediate Contaminated Groundwater

    NASA Technical Reports Server (NTRS)

    2010-01-01

    During the Apollo Program, NASA workers used chlorinated solvents to clean rocket engine components at launch sites. These solvents, known as dense non-aqueous phase liquids, had contaminated launch facilities to the point of near-irreparability. Dr. Jacqueline Quinn and Dr. Kathleen Brooks Loftin of Kennedy Space Center partnered with researchers from the University of Central Florida's chemistry and engineering programs to develop technology capable of remediating the area without great cost or further environmental damage. They called the new invention Emulsified Zero-Valent Iron (EZVI). The groundwater remediation compound is cleaning up polluted areas all around the world and is, to date, NASA's most licensed technology.

  8. The oxygen isotope composition of dissolved chromate: a new tool for determining sources of chromium contamination in groundwater

    NASA Astrophysics Data System (ADS)

    Bullen, T.; Widory, D.

    2009-05-01

    Hexavalent chromium (Cr(VI)) is a widespread carcinogen in groundwater, derived from both anthropogenic and natural sources. A large range of chromium isotope composition has been demonstrated for dissolved Cr(VI) in groundwater, resulting from the large isotope fractionation accompanying reduction of Cr(VI) to trivalent chromium (Cr(III)). As a result, the isotopic composition of chromium in dissolved chromate is beginning to prove useful for determining the sources of chromium in contaminated groundwater, but considered alone can likewise be non-diagnostic due to overlapping compositional ranges of potential anthropogenic and natural sources. Based on the strong Cr-O bond in the chromate molecule implied by the large chromium isotope fractionation accompanying Cr(VI) reduction, we have proposed that oxygen will remain closely linked to chromium in the chromate molecule and thus can be used to better constrain chromate sources through a Cr-O "multi-tracer" approach. In a series of laboratory experiments using isotopically "enriched" water and "normal" chromate, we have demonstrated that there is insignificant isotopic exchange between oxygen in chromate and water for residence times as long as one year, and thus chromate will retain the oxygen isotope composition of its source during extended transport in groundwater. We have likewise demonstrated that sufficient chromate for oxygen isotope analysis can be successfully isolated from a chemically complex groundwater sample through a series of precipitation, ion exchange and heating procedures. Although our current approach of measuring 100 micromolar samples of chromate using TCEA- gas mass spectrometry is straightforward and robust, we are also developing a negative-ion thermal ionization mass spectrometry technique in order to greatly reduce the sample size requirement. We are currently applying this novel technique at an electric power facility in California and a metal plating facility in France in order to better determine chromate sources at those sites.

  9. Michalak, A.M., and P.K. Kitanidis, "Application of Geostatistical Inverse Modeling to Contaminant Source Identification at Dover AFB, Delaware," in International Groundwater Symposium: Bridging the Gap between Measurement and Modeling in Heterogeneous Me

    E-print Network

    Michalak, Anna M.

    Source Identification at Dover AFB, Delaware," in International Groundwater Symposium: Bridging the Gap of geostatistical inverse modeling to contaminant source identification at Dover AFB, Delaware Anna M. Michalak

  10. Using groundwater age to understand sources and dynamics of nutrient contamination through the catchment into Lake Rotorua, New Zealand

    NASA Astrophysics Data System (ADS)

    Morgenstern, U.; Daughney, C. J.; Leonard, G.; Gordon, D.; Donath, F. M.; Reeves, R.

    2014-08-01

    The water quality of Lake Rotorua has declined continuously over the past 50 yr despite mitigation efforts over recent decades. Delayed response of the groundwater discharges to historic land-use intensification 50 yr ago was the reason suggested by early tritium measurements, which indicated large transit times through the groundwater system. We use the isotopic and chemistry signature of the groundwater for detailed understanding of the origin, fate, flow pathways, lag times, and future loads of contaminants. A unique set of high-quality tritium data over more than four decades, encompassing the time when the tritium spike from nuclear weapons testing moved through the groundwater system, allows us to determine detailed age distribution parameters of the water discharging into Lake Rotorua. The Rotorua volcanic groundwater system is complicated due to the highly complex geology that has evolved through volcanic activity. Vertical and steeply-inclined geological contacts preclude a simple flow model. The extent of the Lake Rotorua groundwater catchment is difficult to establish due to the deep water table in large areas, combined with inhomogeneous groundwater flow patterns. Hierarchical cluster analysis of the water chemistry parameters provided evidence of the recharge source of the large springs near the lake shore, with discharge from the Mamaku ignimbrite through lake sediment layers. Groundwater chemistry and age data show clearly the source of nutrients that cause lake eutrophication, nitrate from agricultural activities and phosphate from geologic sources. With a naturally high phosphate load reaching the lake continuously via all streams, the only effective way to limit algae blooms and improve lake water quality in such environments is by limiting the nitrate load. The groundwater in the Rotorua catchment, once it has passed through the soil zone, shows no further decrease in dissolved oxygen, indicating absence of electron donors in the aquifer that could facilitate microbial denitrification reactions. Nitrate from land-use activities that leaches out of the root zone of agricultural land into the deeper part of the groundwater system must be expected to travel with the groundwater to the lake. The old age and the highly mixed nature of the water discharges imply a very slow and lagged response of the streams and the lake to anthropogenic contaminants in the catchment, such as nitrate. Using the age distribution as deduced from tritium time series data measured in the stream discharges into the lake allows prediction of future nutrient loads from historic land-use activities 50 yr ago. For Hamurana Stream, the largest stream to Lake Rotorua, it takes more than a hundred years for the groundwater-dominated stream discharge to adjust to changes in land-use activities. These time scales apply to activities that cause contamination, but also to remediation action.

  11. Delineating Fecal Contaminant Sources and Travel Times in a Karst Groundwater Basin, Inner Bluegrass Region, Kentucky

    NASA Astrophysics Data System (ADS)

    Ward, J. W.; Reed, T. M.; Fryar, A. E.; Brion, G. M.

    2006-12-01

    Because of preferential flowpaths via features such as sinkholes and conduits, karst aquifers are susceptible to non-point-source pollution from agricultural and urban drainage. With many karst aquifers being drinking- water sources, pathogens are contaminants of public health concern. Monitoring of microbial parameters (total coliforms [TC], atypical colonies [AC] and fecal coliform bacteria [FC]) transpired biweekly from December 2002 March 2004 and weekly from February October 2005 at Blue Hole Spring, which drains outlying farm lands and the town of Versailles in the Inner Bluegrass Region of Kentucky. Physicochemical parameters (discharge, temperature, specific conductance, and pH) were measured continuously during the entire period. The AC/TC ratio, which had been employed only in surface water-quality studies, was used with FC counts, precipitation and discharge data to determine sources of fecal loading to ground water as result of land-use practices. An AC/TC ratio < 10 demonstrates fresh input of fecal matter, while a larger ratio can represent a variety of occurrences, including aged fecal material input and/or lack of nutrient input into the system. AC/TC ratio data in the 2002 04 dataset behaved similarly to surface waters, with ratios > 10 during dry periods and < 10 during wet periods, while the 2005 data demonstrated a very irregular pattern. The difference in these two data sets indicated a compositional change within the groundwater basin between the two sampling periods, perhaps as a result of construction at a sewage treatment plant adjoining the spring. Solute (rhodamine WT fluorescent dye and bromide) and particle (1-?m diameter fluorescent latex microspheres) tracer tests were conducted during summer 2006 to examine contaminant mobility within the system under base-flow and storm-flow conditions. Rainfall was limited prior to the base-flow trace, totaling 0.025 cm within 2 weeks prior to the slug injection. Base-flow discharge averaged 400 m3/s and solute breakthrough began ~ 7.5 hours post injection and cleared the system after 77 hours. For the storm-flow trace, rainfall totaled 3.12 cm prior to injection, with another 9.35 cm of rainfall occurring over the two week monitoring period. Spring discharge during the storm-flow trace averaged 0.443 m3/s, with a maximum of 0.503 m3/s. Under storm-flow conditions solute breakthrough began ~ 2.33 hours post injection, with particle breakthrough beginning ~ 2.5 hours post injection. Bromide concentrations at the spring were < 0.1 ppm (the detection limit, or DL) 5.5 hours after injection, while rhodamine WT concentrations were < DL (0.1 ppb) 14 hours post injection. Microspheres were detected at the spring until 164 hours after injection. These traces demonstrate that storms in this karst basin can accelerate solute movement, and particles can remain mobile for as long as 1 week after introduction.

  12. Dealing with contaminated groundwater sites

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2012-11-01

    Dealing with contaminated groundwater sites Restoration of about 12,000 “problematic” contaminated groundwater sites across the United States is unlikely to be achieved in the next 50-100 years, according to an 8 November report by a committee of the U.S. National Research Council.

  13. Evaluation for Early Life Stage Fall Chinook Salmon Exposed to Hexavalent Chromium from a Contaminated Groundwater Source

    SciTech Connect

    Patton, Gregory W.; Dauble, Dennis D.; McKinstry, Craig A.

    2007-09-01

    We conducted a laboratory evaluation to assess the risk to early life stage (i.e., eyed egg to swim up) fall Chinook salmon (Oncorhynchus tshawytscha) for exposure to hexavalent chromium from a contaminated groundwater source. Local populations of fall Chinook salmon were exposed to Hanford Site source groundwater that was diluted with Columbia River water. Specific endpoints included survival, development rate, and growth. Tissue burdens of fish were also measured to estimate uptake and elimination rates of chromium. Survival, development, and growth of early life stage fall Chinook salmon were not adversely affected by extended exposures (i.e., 98 day) to hexavalent chromium ranging from 0.79 to 260 ?g/L. Survival for all treatment levels and controls exceeded 98% at termination of the test. In addition, there were no differences among the mean lengths and weights of fish among all treatment groups. Whole-body concentrations of chromium in early life stage fall Chinook salmon had a typical dose-response pattern; i.e., those subjected to highest exposure concentrations and longest exposure intervals had higher tissue concentrations. Given the spatial extent of chromium concentrations at the Hanford Site, and the dynamics of the groundwater - river water interface, the current cleanup criterion of 10 µg/L chromium appear adequate to protect fall Chinook salmon populations.

  14. Long-term Groundwater Contamination after Source Removal: Role of Sorbed Carbon and Nitrogen at Cape Cod, MA

    NASA Astrophysics Data System (ADS)

    Smith, R. L.; Repert, D.; Barber, L. B.; Fairchild, G.; Leblanc, D. R.

    2010-12-01

    The consequences of groundwater contamination can remain long after a contaminant source has been removed. This can be the case even for constituents that are primarily water-soluble, such as treated wastewater. Yet, documentation of natural aquifer recoveries and empirical tools to predict recovery time frames and down-gradient impacts are generally lacking. We have been characterizing the long-term natural attenuation of a groundwater plume in a sand and gravel aquifer after the removal of the treated wastewater source on Cape Cod, Massachusetts. Although dissolved organic carbon (OC) and other soluble constituents have decreased substantially in concentration, after >14 years post source removal, the core of the plume remains anoxic, with extensive redox gradients and persistence of nitrate, ammonium, and phosphorus. Core material was collected from the former disposal site at several points in time and along a 0.4 km transect downgradient from the disposal site and correlated with changes in plume composition. Oxygen consumption capacity for the core material ranged from 12-54 nmol gr-1 day-1 and was positively correlated with both total and water-extractable OC. Total extractable OC ranged up to 2.9 µmol C (gr dry wt)-1. Extraction C/N ratios increased with time from 9 to >90, suggesting that OC degradation and oxygen consumption will become N-limited with time as the sorbed C and N pools separate by differential desorption. There was no quantifiable decrease in sorbed OC along the transect or with time, suggesting that the total sorbed carbon pool is large and will be impacting groundwater geochemistry for many decades. However, there is evidence of increased oxygen concentrations along the plume margins, which can provide upper limit estimates for in situ oxygen consumption kinetics and the relative rate of oxygen entrainment into the anoxic plume core.

  15. 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.

  16. Source and fate of nitrate contamination in the groundwater along its flow in Kumamoto area, Japan using ?15NNO3 and ?18ONO3

    NASA Astrophysics Data System (ADS)

    Tokunaga, T.; Shimada, J.; Hosono, T.; Nakata, H.; Kagabu, M.; Ono, M.; Orishikida, T.; Kumamoto Univ

    2011-12-01

    Kumamoto is a famous city for groundwater in Japan and its drinking water is fully dependent on groundwater. Groundwater nitrate-nitrogen contamination has increasingly been observed in the aquifer system of Kumamoto area. Actually, NO3-N concentrations in some groundwaters have been exceeding 10 mg/L. However, the cause of nitrate pollution has not yet been fully clarified and this issue needs to be addressed for sustainable utilization of groundwater in this region. The purpose of our study is to clarify the source and fate of nitrate contamination in Kumamoto groundwater by using ?15NNO3 and ?18ONO3. The main land-use is consisting of farm land in upland areas, rice paddies in the lowlands, and residential areas in the lowland area of the Kumamoto plain.Water samples for chemical and isotopic characterization were collected in October 2010 and January to March 2011 from 30 production wells. NO3-N concentrations in the groundwater were highest in highland areas where groundwater recharges in the agricultural zone. Dual nitrate isotope ratios clearly support the idea that nitrate contamination was due to the input of agricultural fertilizers applied in this recharge area. On the other hand, in the coastal area, where unoxic environment develops, significant denitrification effect was confirmed from the sample plot signature on concentration-?15NNO3 diagram. Our results should be important information to be used in the program of groundwater resource management of the Kumamoto City.

  17. GROUNDWATER CONTAMINATION FROM STORMWATER INFILTRATION

    Microsoft Academic Search

    Robert Pitt; Shirley Clark; Keith Parmer; Richard Field; Thomas P. O'Connor

    INlRODUCTlON The research summarized here was conducted during the first year of a 3-yr cooperative agreement (CR819573) to identify and control stormwater toxicants, especially those adversely affecting groundwater. The purpose of this research effort was to review the groundwater contamination literature as it relates to stormwater. Prior to urbanization groundwater is recharged by rainfall-runoff and snowmelt infiltrating through pervious surfaces

  18. Groundwater Contamination Potential from Stormwater

    E-print Network

    Clark, Shirley E.

    1 Groundwater Contamination Potential from Stormwater Infiltration Robert Pitt, University Introduction · Infiltration of stormwater has become an increasingly important stormwater management tool stormwater management devices in Florida and Long Island · A number of communities throughout the world

  19. Sources and Transport of Arsenic Contaminating Shallow Groundwater in the Historical Industrial Zone of Monterrey City, Nuevo León, México

    NASA Astrophysics Data System (ADS)

    Romero, F. M.; Gutierrez-Ruiz, M. E.; Villalobos, M.

    2007-05-01

    Arsenic contamination has been detected in a shallow aquifer of the geographical center of Monterrey City, in the Northeast of Mexico, and where the historical industrial zone of the city is located, reaching concentrations of up to 3.1 mg/L. A metallurgical plant that operated more than a 100 years and closed down in 1999 is identified as a possible pollution source because it deposited arsenic-rich wastes in the fields adjoining it, showing total arsenic contents that reach up to 1-2 % As in weight. We deem arsenic transport through the soil profile as highly unlikely based on the following experimental and field evidence: water-soluble arsenic contents in 1:20 soil:water extracts of both surface and subsurface samples is very low, showing values in a majority of samples below 1 mg As/L; the unsatured zone under the inactive plant is characterized by the presence of two impermeable clay layers (hydraulic conductivities of 2.1 x 10-8 cm-1 to 8.4 x 10-8 cm-1), the first one occurring at 0.6 to 1 m below the surface, and the second one at approximately 17 m below the surface; arsenic analyses of several core samples from boreholes 40 m deep show that As released at the soil surface is completely retained in the upper clay layer. Nevertheless, the highest dissolved arsenic concentrations (1.1 to 3.1 mg/L) were found in wells from shallow groundwater from active industries located to the north of the inactive plant. The groundwater flux in the area goes in a direction west to east, therefore, the source of these arsenic levels cannot come from the inactive plant premises and indicates the occurrence of additional sources of arsenic groundwater contamination. The evidence points to the fact that the most likely cause of shallow groundwater contamination inside the inactive plant is via surface runoff of deposited wastes during the rainy season, into drilled boreholes in the area. This is supported by a 10-year semester analysis database. Therefore, the authors recommend a suitable and immediate closure of these boreholes.

  20. Evaluation of ground-water contamination from nonpoint sources: A case study

    Microsoft Academic Search

    C. van den Brink; W. J. Zaadnorrdijk

    1995-01-01

    In many countries a substantial part of the drinking-water supply comes from subsurface-water resources. During the last several decades an increasing extent of diffuse pollution has endangered these water resources. Knowledge of the changes in ground-water quality is necessary in order to known if, and to what extent, ground-water quality is endangered. Changes in ground-water quality can be predicted by

  1. Groundwater recharge and agricultural contamination

    USGS Publications Warehouse

    Böhlke, J.K.

    2002-01-01

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

  2. Use of stable isotopes to differentiate between multiple groundwater contaminant sources

    SciTech Connect

    Kim, P.Y.; Bovitz, P.; VanDerveer, B.; Donohue, M.; Sprenger, M.; Munney, K.

    1994-12-31

    A wildlife kill in a northeastern freshwater pond, downgradient of a municipal landfill, was investigated. Chemical analyses of water, sediment, minnow (Pimephales sp.), and newt (Notophthalmus sp.) tissue was conducted in conjunction with histopathological analyses, toxicity evaluations, and a site reconnaissance. Elevated levels of volatile organic compounds (VOCs), Aroclor 1248, cyanide, and metals in water, sediment, and tissue suggested that contaminants were released into the pond from an upgradient source. In addition, the presence of a floating oil on the pond surface (originating from an upgradient source) exceeded the US EPA Ambient Water Quality Criterion for oil and grease. Bacterial, parasitological, and histopathological tests conducted on minnow tissue did not implicate any pathogenic organism to be associated with mortality. Results of the toxicity evaluation of seep water from the upgradient source revealed a significant (p < 0.05) reduction in survival and growth of fathead minnows (Pimephales promelas) from the control. Water quality parameters measured at the time of the field investigation revealed normal conditions.

  3. GIS Techniques for Mapping Groundwater Contamination Risk

    Microsoft Academic Search

    Daniela Ducci

    1999-01-01

    The groundwater contamination risk map of a samplealluvial area was produced by using the IlwisGeographical Information System (GIS) to construct andto overlay thematic maps. The risk map has beenderived from the vulnerability map, the hazard map,where the potential contaminating sources wereidentified, and the socio-economic value of thegroundwater resource, represented by the wells. Thegroundwater quality map allowed thereliability of hazard and

  4. Arsenic Contamination of Groundwater at Zimapán, Mexiko

    Microsoft Academic Search

    M. A. Armienta; R. Rodriguez; A. Aguayo; N. Ceniceros; G. Villaseñor; O. Cruz

    1997-01-01

    Arsenic contamination of groundwater has been detected in the Zimapán Valley, Mexico. Concentrations as much as 1.097 mg\\/L were observed in water pumped from one of the most productive wells. Three sources of arsenic are known. The natural source is produced by the oxidation of arsenic-bearing minerals; polluted water pumped from the deepest wells is derived from this source and

  5. Arsenic contamination of groundwater: Mitigation strategies and policies

    Microsoft Academic Search

    Guy J. Alaerts; Nadim Khouri

    2004-01-01

    Contamination of groundwater by arsenic from natural geochemical sources is at present a most serious challenge in the planning of large-scale use of groundwater for drinking and other purposes. Recent improvements in detection limits of analytical instruments are allowing the correlation of health impacts such as cancer with large concentrations of arsenic in groundwater. However, there are at present no

  6. Evaluating potential groundwater contamination from contaminated soils

    SciTech Connect

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

    1987-01-01

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

  7. Identifying and Quantifying transient groundwater fluxes and fluxes of contaminated sources of recharge into complex groundwater reservoir by Mixing Cells Modeling approach.

    NASA Astrophysics Data System (ADS)

    Adar, Eilon; Massoth, Sylvie

    2013-04-01

    Groundwater reservoirs are rarely isolated. Usually production aquifers are affected by hydraulically connected to neighboring sub-aquifers units and nearby water baring formations with different water qualities and dissolved mineral contents. These results long term special and temporal variations in groundwater quality of production aquifers. Phreatic aquifers are prone to on-surface anthropogenic activities, although it is clear that even confined aquifers are negatively affected down the years by percolation of contaminants that gradually percolate into groundwater reservoirs over the recharge area. Even massive groundwater abstraction reveals almost a steady flow system after several years. However the differential fluxes from neighboring sub-aquifers attracted into the production aquifer cause long-term temporal distribution of the groundwater quality. The main issue is how to firmly identify the hydraulic connectivity among the various sub aquifers, and to draw the solid pathways among the connected active water bearing units. Beyond that, these processes often prevail under announcing a non-steady aquifers environment as function of massive groundwater abstraction. This results gradual yet substantial spatial and temporal variations in chemical and dissolved minerals distribution, all which suggest on transient flow and mass transport distribution. For such complex aquifers system, where the hydrologic conditions along the boundaries cannot be well-defined, the transient Mixing Cells Modeling approach MCMusf (unsteady flow) is proposed to illuminate on the active flow paths and to assess the transient groundwater fluxes within the aquifer. The presentation will elaborate on the mathematical set up of the newly developed MCMusf code for transient flow system, and on a feasible solution which is based on linear optimization scheme.

  8. Comparing Groundwater Contamination Vulnerability in Large, Urbanized Basins of California

    Microsoft Academic Search

    J. E. Moran; G. B. Hudson; R. Leif; G. F. Eaton

    2002-01-01

    We have sampled over 700 public drinking water wells as part of a study to assess relative contamination susceptibility of the major groundwater basins in California. The parameters used to rank wells according to vulnerability are groundwater age dates (using the tritium-3helium method), stable isotopes of the water molecule (for water source determination), and occurrence of low level Volatile Organic

  9. Recent advances in the bioremediation of arsenic-contaminated groundwaters

    Microsoft Academic Search

    Anastasios I. Zouboulis; Ioannis A. Katsoyiannis

    2005-01-01

    The biological treatment of groundwaters is used primarily to remove electron donors from water sources, providing (biologically) stable drinking water, which preclude bacterial regrowth during subsequent water distribution. To the electron donors belong also the dissolved metal cations of ferrous iron and manganese, which are common contaminants found in most (anaerobic) groundwaters. The removal of iron and manganese is usually

  10. A model for evaluating the three-dimensional groundwater dividing pathline between a contaminant source and a partially penetrating water-supply well

    NASA Astrophysics Data System (ADS)

    Harmsen, Eric W.; Converse, James C.; Anderson, Mary P.; Hoopes, John A.

    1991-09-01

    Effluent from septic tank-drainfields can degrade groundwater quality and contaminate nearby water-supply wells. Such groundwater contamination is a problem in the unsewered subdivisions of the sand plain of central Wisconsin, for example. To help planners minimize the risk of direct contamination of a water-supply well by a septic system, a model was developed to estimate the location of the critical dividing pathline between a rectangular contaminant source (the septic tank drainfield) and a partially penetrating pumping well. The model is capable of handling three-dimensional, transient flow in an unconfined, homogeneous, anisotropic aquifer of infinite areal extent, under a regional horizontal hydraulic gradient. Model results are in very good agreement with several other numerical and analytical models. Examples are given for which the safe, horizontal and vertical separation distances to avoid well water contamination are determined for typical central Wisconsin sand plain conditions. A companion paper (Harmsen et al., 1991) describes the application of this model, using a Monte-Carlo analysis, to study the variation of these separation distances in the Wisconsin sand plain. The model can also be applied to larger scale problems and, therefore, could be useful in implementing the U.S. Environmental Protection Agency's new well head protection program.

  11. Response of the microbial community to seasonal groundwater level fluctuations in petroleum hydrocarbon-contaminated groundwater.

    PubMed

    Zhou, Ai-Xia; Zhang, Yu-Ling; Dong, Tian-Zi; Lin, Xue-Yu; Su, Xiao-Si

    2015-07-01

    The effects of seasonal groundwater level fluctuations on the contamination characteristics of total petroleum hydrocarbons (TPH) in soils, groundwater, and the microbial community were investigated at a typical petrochemical site in northern China. The measurements of groundwater and soil at different depths showed that significant TPH residue was present in the soil in this study area, especially in the vicinity of the pollution source, where TPH concentrations were up to 2600 mg kg(-1). The TPH concentration in the groundwater fluctuated seasonally, and the maximum variation was 0.8 mg L(-1). The highest TPH concentrations were detected in the silty clay layer and lied in the groundwater level fluctuation zones. The groundwater could reach previously contaminated areas in the soil, leading to higher groundwater TPH concentrations as TPH leaches into the groundwater. The coincident variation of the electron acceptors and TPH concentration with groundwater-table fluctuations affected the microbial communities in groundwater. The microbial community structure was significantly different between the wet and dry seasons. The canonical correspondence analysis (CCA) results showed that in the wet season, TPH, NO3 (-), Fe(2+), TMn, S(2-), and HCO3 (-) were the major factors correlating the microbial community. A significant increase in abundance of operational taxonomic unit J1 (97 % similar to Dechloromonas aromatica sp.) was also observed in wet season conditions, indicating an intense denitrifying activity in the wet season environment. In the dry season, due to weak groundwater level fluctuations and low temperature of groundwater, the microbial activity was weak. But iron and sulfate-reducing were also detected in dry season at this site. As a whole, groundwater-table fluctuations would affect the distribution, transport, and biodegradation of the contaminants. These results may be valuable for the control and remediation of soil and groundwater pollution at this site and in other petrochemical-contaminated areas. Furthermore, they are probably helpful for reducing health risks to the general public from contaminated groundwater. PMID:25687607

  12. In situ bioremediation of petrol contaminated groundwater

    E-print Network

    Blouin-Demers, Gabriel

    21/11/08 1 In situ bioremediation of petrol contaminated groundwater Guido Miguel Delgadillo EVS and facts · Likelihood of contamination · Benefits of in situ bioremediation So... Ask not what groundwater · Intrinsic BR vs. Engineered BR Anaerobic Bioremediation (1) Background · Anaerobic conditions most likely

  13. Extent and Severity of Groundwater Arsenic Contamination in Bangladesh

    Microsoft Academic Search

    Toshihiko Kawachi; Eiji Ichion

    2001-01-01

    In Bangladesh, the majority of the irrigation and drinking water is supplied from underground sources due to the limitation of surface water. In recent years, arsenic contamination has emerged as a fresh blow to the country. This paper gives an overview of the extent and severity of groundwater arsenic contamination in Bangladesh, as well as a review of the latest

  14. A stochastic method for characterizing ground-water contamination

    Microsoft Academic Search

    D. McLaughlin; L. B. Reid; Shuguang Li; J. Hyman

    2009-01-01

    It is becoming widely recognized that field-scale ground-water contaminant plumes are irregular and difficult to predict. Factors which complicate the characterization of such plumes include geological variability, data limitations, and uncertainties about the source of contamination. This paper describes a new approach to site characterization which accounts for variability and uncertainty in a systematic way. The site characterization procedure extracts

  15. Implications of uncertainty in exposure assessment for groundwater contamination

    USGS Publications Warehouse

    Reichard, Eric G.; Izbicki, John A.; Martin, Peter

    1995-01-01

    Decision-making on regulation, mitigation, and treatment of drinking water contamination depends, in part, on estimates of human exposure. Assessment of past, present and potential future exposure levels requires quantitative characterization of the contaminant sources, the transport of contaminants and the level of actual human exposure to the contaminated water. Failure to consider the uncertainties in these three components of exposure assessment can lead to poor decisions such as implementing an inappropriate mitigation strategy or failing to regulate an important contaminant. Three examples from US Geological Survey hydrogeologic studies in southern California are presented to illustrate some of the unique uncertainties associated with exposure assessment for groundwater contamination.

  16. Assessing groundwater vulnerability to agrichemical contamination in the Midwest US

    USGS Publications Warehouse

    Burkart, M.R.; Kolpin, D.W.; James, D.E.

    1999-01-01

    Agrichemicals (herbicides and nitrate) are significant sources of diffuse pollution to groundwater. Indirect methods are needed to assess the potential for groundwater contamination by diffuse sources because groundwater monitoring is too costly to adequately define the geographic extent of contamination at a regional or national scale. This paper presents examples of the application of statistical, overlay and index, and process-based modeling methods for groundwater vulnerability assessments to a variety of data from the Midwest U.S. The principles for vulnerability assessment include both intrinsic (pedologic, climatologic, and hydrogeologic factors) and specific (contaminant and other anthropogenic factors) vulnerability of a location. Statistical methods use the frequency of contaminant occurrence, contaminant concentration, or contamination probability as a response variable. Statistical assessments are useful for defining the relations among explanatory and response variables whether they define intrinsic or specific vulnerability. Multivariate statistical analyses are useful for ranking variables critical to estimating water quality responses of interest. Overlay and index methods involve intersecting maps of intrinsic and specific vulnerability properties and indexing the variables by applying appropriate weights. Deterministic models use process-based equations to simulate contaminant transport and are distinguished from the other methods in their potential to predict contaminant transport in both space and time. An example of a one-dimensional leaching model linked to a geographic information system (GIS) to define a regional metamodel for contamination in the Midwest is included.

  17. Groundwater nitrate contamination: Factors and indicators

    PubMed Central

    Wick, Katharina; Heumesser, Christine; Schmid, Erwin

    2012-01-01

    Identifying significant determinants of groundwater nitrate contamination is critical in order to define sensible agri-environmental indicators that support the design, enforcement, and monitoring of regulatory policies. We use data from approximately 1200 Austrian municipalities to provide a detailed statistical analysis of (1) the factors influencing groundwater nitrate contamination and (2) the predictive capacity of the Gross Nitrogen Balance, one of the most commonly used agri-environmental indicators. We find that the percentage of cropland in a given region correlates positively with nitrate concentration in groundwater. Additionally, environmental characteristics such as temperature and precipitation are important co-factors. Higher average temperatures result in lower nitrate contamination of groundwater, possibly due to increased evapotranspiration. Higher average precipitation dilutes nitrates in the soil, further reducing groundwater nitrate concentration. Finally, we assess whether the Gross Nitrogen Balance is a valid predictor of groundwater nitrate contamination. Our regression analysis reveals that the Gross Nitrogen Balance is a statistically significant predictor for nitrate contamination. We also show that its predictive power can be improved if we account for average regional precipitation. The Gross Nitrogen Balance predicts nitrate contamination in groundwater more precisely in regions with higher average precipitation. PMID:22906701

  18. Using cassava distiller's dried grains as carbon and microbe sources to enhance denitrification of nitrate-contaminated groundwater.

    PubMed

    Wan, Rui; Zheng, Xiong; Chen, Yinguang; Wang, Huaichen

    2015-03-01

    Nitrate removal from synthetic and real groundwater was investigated by using cassava distiller's dried grains (CDDG), which served as sole carbon source as well as the only microbe seed. It was found that remarkably higher total nitrogen removal efficiency (96.8 ± 0.6 %) could be reached; the accumulation of nitrite and the releases of organic compounds, meanwhile, were insignificant in the denitrification process. Scanning electron microscope (SEM) analysis showed that CDDG were degraded during the denitrification process. Further investigation showed that CDDG were anaerobically hydrolyzed and acidified to butyric acid, acetic acid, and carbohydrate, which could be utilized directly as the reducing equivalent providers for denitrification by the microorganisms separated from CDDG. Microbial community analysis revealed that the fungi and bacteria present in the original CDDG functioned as the denitrifiers, which mainly consisted of Aspergillus (69.8 %) and Rhizomucor (15.9 %) in the fungi community and Burkholderia (20.6 %) and Rhizobium (15.9 %) in the bacteria community, respectively. Finally, the use of CDDG as both carbon and microbial sources for real groundwater denitrification was testified to be feasible and safe with a total nitrogen removal efficiency of around 100 %. PMID:25343978

  19. Predicting Groundwater Contamination beneath Stormwater Infiltration

    E-print Network

    Clark, Shirley E.

    1 Predicting Groundwater Contamination beneath Stormwater Infiltration Activities Shirley E. Clark, Penn State Harrisburg Robert Pitt, University of Alabama Pollutants of Concern · Classes of stormwaterHighest Observed Concentration Metal Are these waters infiltration quality? Benefits of Urban Stormwater

  20. REMOVAL OF ORGANIC CONTAMINANTS FROM GROUNDWATER.

    EPA Science Inventory

    More are than lOO million Americans depend on groundwater as a source of drinking water. hree quarters of U.S. cities get their water supplies totally or in part from groundwater and one-third of the largest cities rely on groundwater for at least part of their potable water supp...

  1. Impact Of Groundwater Discharge On Contaminant Behavior In Sediments

    EPA Science Inventory

    The discharge of groundwater into surface water may influence the concentrations and availability of contaminants in sediments. There are three predominant pathways by which groundwater may affect the characteristics of contaminated sediments: 1) direct contribution of contamin...

  2. A Contamination Vulnerability Assessment for the Sacramento Area Groundwater Basin

    SciTech Connect

    Moran, J E; Hudson, G B; Eaton, G F; Leif, R

    2004-03-10

    In response to concerns expressed by the California Legislature and the citizenry of the State of California, the State Water Resources Control Board (SWRCB), implemented a program to assess groundwater quality, and provide a predictive capability for identifying areas that are vulnerable to contamination. The program was initiated in response to concern over public supply well closures due to contamination by chemicals such as MtBE from gasoline, and solvents from industrial operations. As a result of this increased awareness regarding groundwater quality, the Supplemental Report of the 1999 Budget Act mandated the SWRCB to develop a comprehensive ambient groundwater-monitoring plan, and led to the initiation of the Ambient Groundwater Monitoring and Assessment (GAMA) Program. The primary objective of the GAMA Program is to assess the water quality and to predict the relative susceptibility to contamination of groundwater resources throughout the state of California. Under the GAMA program, scientists from Lawrence Livermore National Laboratory (LLNL) collaborate with the SWRCB, the U.S. Geological Survey, the California Department of Health Services (DHS), and the California Department of Water Resources (DWR) to implement the groundwater assessment program in cooperation with local water purveyors. In 2001 and 2002, LLNL carried out this vulnerability study in the groundwater basin of Sacramento suburban area, located to the north of the American River and to the east of the Sacramento River. The goal of the study is to provide a probabilistic assessment of the relative vulnerability of groundwater used for the public water supply to contamination from surface sources. This assessment of relative contamination vulnerability is made based on the results of two types of analyses that are not routinely carried out at public water supply wells: ultra low-level measurement of volatile organic compounds (VOCs), and groundwater age dating (using the tritium-helium-3 method). In addition, stable oxygen isotope measurements help determine the recharge water source. Interpreted together, and in the context of existing water quality and hydrogeologic data, these observable parameters help define the flow field of a groundwater basin, and indicate the degree of vertical communication between near-surface sources (or potential sources) of contamination, and deeper groundwater pumped at high capacity production wells.

  3. Enhanced detection of groundwater contamination from a leaking waste disposal site by microbial community profiles

    E-print Network

    Vermont, University of

    Enhanced detection of groundwater contamination from a leaking waste disposal site by microbial in disposal sites cited as a significant source of groundwater contamination in both the United States into the subsurface from leaking landfills. Detecting leachate contamination using statistical techniques

  4. Can antibiotic resistance analysis be a useful tool for tracking population sources of contamination in Yucatan groundwater?

    NASA Astrophysics Data System (ADS)

    McLain, J. E.; Lenczewski, M.; Leal-Bautista, R. M.

    2013-05-01

    Antibiotic resistance patterns have been widely used in scientific studies conducted to identify sources of water contamination. However, the methods of resistance determination have not been standardized; therefore, the data on antibiotic resistance in the environment come from studies that have used a range of media types, antibiotic concentrations, and incubation periods, making it difficult to compare results between environments. Over two years, we assessed antibiotic sensitivity of Gram-positive and Gram-negative bacteria isolated from Yucatan water sources, to identify unique resistance patterns and assess the potential for antibiotic resistance analysis as a tool to discriminate between fecal pollution from two population sources (tourist and local). Though resistance to erythromycin, streptomycin, and ciprofloxacin showed some differences between populations, natural bacterial resistance (in isolates from pristine sources) was very high and confounded the research findings. This study highlights the need among the research community involved in tracking of environmental antibiotic resistance to develop a standardized and rigorously validated suite of methods that address background resistance and that can be used across environments, to accurately inform source tracking studies.

  5. Groundwater pumping effects on contaminant loading management in agricultural regions.

    PubMed

    Park, Dong Kyu; Bae, Gwang-Ok; Kim, Seong-Kyun; Lee, Kang-Kun

    2014-06-15

    Groundwater pumping changes the behavior of subsurface water, including the location of the water table and characteristics of the flow system, and eventually affects the fate of contaminants, such as nitrate from agricultural fertilizers. The objectives of this study were to demonstrate the importance of considering the existing pumping conditions for contaminant loading management and to develop a management model to obtain a contaminant loading design more appropriate and practical for agricultural regions where groundwater pumping is common. Results from this study found that optimal designs for contaminant loading could be determined differently when the existing pumping conditions were considered. This study also showed that prediction of contamination and contaminant loading management without considering pumping activities might be unrealistic. Motivated by these results, a management model optimizing the permissible on-ground contaminant loading mass together with pumping rates was developed and applied to field investigation and monitoring data from Icheon, Korea. The analytical solution for 1-D unsaturated solute transport was integrated with the 3-D saturated solute transport model in order to approximate the fate of contaminants loaded periodically from on-ground sources. This model was further expanded to manage agricultural contaminant loading in regions where groundwater extraction tends to be concentrated in a specific period of time, such as during the rice-growing season, using a method that approximates contaminant leaching to a fluctuating water table. The results illustrated that the simultaneous management of groundwater quantity and quality was effective and appropriate to the agricultural contaminant loading management and the model developed in this study, which can consider time-variant pumping, could be used to accurately estimate and to reasonably manage contaminant loading in agricultural areas. PMID:24681649

  6. Determining sources of water and contaminants to wells in a carbonate aquifer near Martinsburg, Blair County, Pennsylvania, by use of geochemical indicators, analysis of anthropogenic contaminants, and simulation of ground-water flow

    USGS Publications Warehouse

    Lindsey, Bruce D.; Koch, Michele L.

    2004-01-01

    Water supply for the Borough of Martinsburg, Pa., is from two well fields (Wineland and Hershberger) completed in carbonate-bedrock aquifers in the Morrison Cove Valley. Water supply is plentiful; however, waters with high concentrations of nitrate are a concern. This report describes the sources of water and contaminants to the supply wells. A review of previous investigations was used to establish the aquifer framework and estimate aquifer hydraulic properties. Aquifer framework and simulation of ground-water flow in a 25-square-mile area using the MODFLOW model helped to further constrain aquifer hydraulic properties and identify water-source areas in the zone of contribution of ground water to the well fields. Flow simulation identified potential contaminant-source areas. Data on contaminants and geochemical characteristics of ground water at the well fields were compared to the results of flow simulation. The Woodbury Anticline controls the aquifer framework near the well fields and four carbonate-bedrock formations contain the primary aquifers. Three carbonate-bedrock aquifers of Ordovician age overlie the Gatesburg aquifer of Cambrian age on the flanks of the anticline. Fracture, not conduit, permeability was determined to be the dominant water-bearing characteristic of the bedrock. The horizontal hydraulic conductivity of the Gatesburg aquifer is about 36 feet per day. The other carbonate aquifers (Nittany/Stonehenge, Bellefonte/Axemann, and Coburn through Loysburg aquifers) overlying and flanking the Gatesburg aquifer have horizontal hydraulic conductivities of about 1 foot per day. Regional directions of ground-water flow are toward the major streams with Clover Creek as the major discharge point for ground water in the east. Ground-water flow to the well fields is anisotropic with a 5:1 preferential horizontal direction along strike of the axial fold of the anticline. Thus, the zone of contribution of ground water to the well fields is elongate in a north-south direction along the anticline axis, with the majority of the flow to the well fields originating from the south. Human activity in the areal extent of the zone of contribution to the well fields was the source of contaminants. The areal extent of the zone of contribution included both urban areas in the Borough and a large amount of agricultural land. By relating results of flow simulation, natural geochemistry, and analyses of anthropogenic (human-made) contaminants, the source areas for water and contaminants were determined with more confidence than by using only flow simulation. Analysis of natural geochemistry identified water sources from both limestone and dolomite aquifers. Geochemistry results also indicated fractures, not conduits, were the dominant source of water from aquifers; however, quantitative source identification was not possible. Chemical ratios of chloride and bromide were useful to show that all samples of ground water had sources with chemical contributions from land surface. Nitrogen isotope ratio analysis indicated animal manure as the possible primary source of nitrate in most ground water. Some of the nitrate in ground water had chemical fertilizer as a source. At the Wineland well field, chemical fertilizer was likely the source of nitrate. The nitrate in water from the Hershberger well field was from a mixture of fertilizer and animal-manure sources. Human sewage was ruled out as a major source of nitrate in water from the municipal wells by results showing 1) wastewater compounds in sewage were rarely detected and 2) a mass-balance calculation indicating the small contribution of nitrogen that could be attributed to septic systems.

  7. AGRICULTURAL CONTAMINANTS REMOVAL FROM GROUNDWATER BY CARBON AND REVERSE OSMOSIS

    EPA Science Inventory

    The groundwater of Suffolk County, New York, is designated as a sole source aquifer and in recent years there have been increasing concerns about the contamination of this water by agricultural chemicals. Two parallel treatment systems were evaluated for a one-year period: granul...

  8. Probabilistic screening tool for ground-water contamination assessment

    Microsoft Academic Search

    Maged M. Hamed; Joel P. Conte; Philip B. Bedient

    1995-01-01

    This paper presents a methodology for assessing the effects of source-, chemical-, and aquifer-related parameter uncertainty on the response of a semianalytical transport model using first- and second-order reliability methods. A probabilistic model is developed by coupling the deterministic transport model with a general-purpose probability analysis program. Ground-water contamination risk is addressed by evaluating the probability that a given contaminant

  9. Complexity of Groundwater Contaminants at DOE Sites

    SciTech Connect

    Hazen, T.C.; Faybishenko, B.; Jordan, P.

    2010-12-03

    The U.S. Department of Energy (DOE) is responsible for the remediation and long-term stewardship of one of the world's largest groundwater contamination portfolios, with a significant number of plumes containing various contaminants, and considerable total mass and activity. As of 1999, the DOE's Office of Environmental Management was responsible for remediation, waste management, or nuclear materials and facility stabilization at 144 sites in 31 states and one U.S. territory, out of which 109 sites were expected to require long-term stewardship. Currently, 19 DOE sites are on the National Priority List. The total number of contaminated plumes on DOE lands is estimated to be 10,000. However, a significant number of DOE sites have not yet been fully characterized. The most prevalent contaminated media are groundwater and soil, although contaminated sediment, sludge, and surface water also are present. Groundwater, soil, and sediment contamination are present at 72% of all DOE sites. A proper characterization of the contaminant inventory at DOE sites is critical for accomplishing one of the primary DOE missions -- planning basic research to understand the complex physical, chemical, and biological properties of contaminated sites. Note that the definitions of the terms 'site' and 'facility' may differ from one publication to another. In this report, the terms 'site,' 'facility' or 'installation' are used to identify a contiguous land area within the borders of a property, which may contain more than one plume. The term 'plume' is used here to indicate an individual area of contamination, which can be small or large. Even though several publications and databases contain information on groundwater contamination and remediation technologies, no statistical analyses of the contaminant inventory at DOE sites has been prepared since the 1992 report by Riley and Zachara. The DOE Groundwater Data Base (GWD) presents data as of 2003 for 221 groundwater plumes at 60 DOE sites and facilities. Note that Riley and Zachara analyzed the data from only 18 sites/facilities including 91 plumes. In this paper, we present the results of statistical analyses of the data in the GWD as guidance for planning future basic and applied research of groundwater contaminants within the DOE complex. Our analyses include the evaluation of a frequency and ranking of specific contaminants and contaminant groups, contaminant concentrations/activities and total contaminant masses and activities. We also compared the results from analyses of the GWD with those from the 1992 report by Riley and Zachara. The difference between our results and those summarized in the 1992 report by Riley and Zachara could be caused by not only additional releases, but also by the use of modern site characterization methods, which more accurately reveal the extent of groundwater contamination. Contaminated sites within the DOE complex are located in all major geographic regions of the United States, with highly variable geologic, hydrogeologic, soil, and climatic conditions. We assume that the information from the 60 DOE sites included in the GWD are representative for the whole DOE complex. These 60 sites include the major DOE sites and facilities, such as Rocky Flats Environmental Technology Site, Colorado; Idaho National Laboratory, Idaho; Savannah River Site, South Carolina; Oak Ridge Reservation, Tennessee; and Hanford Reservation, Washington. These five sites alone ccount for 71% of the value of the remediation work.

  10. Method to remove uranium/vanadium contamination from groundwater

    DOEpatents

    Metzler, Donald R. (DeBeque, CO); Morrison, Stanley (Grand Junction, CO)

    2004-07-27

    A process for removing uranium/vanadium-based contaminants from groundwater using a primary in-ground treatment media and a pretreatment media that chemically adjusts the groundwater contaminant to provide for optimum treatment by the primary treatment media.

  11. PERFORMANCE MONITORING OF PERMEABLE REACTIVE BARRIERS TO REMEDIATE CONTAMINATED GROUNDWATER

    EPA Science Inventory

    Permeable reactive barriers (PRB's) are an emerging, alternative in-situ approach for remediating groundwater contamination that combine subsurface fluid flow management with a passive chemical treatment zone. Removal of contaminants from the groundwater plume is achieved by alt...

  12. Groundwater Contamination. Instructor Guide. Working for Clean Water: An Information Program for Advisory Groups.

    ERIC Educational Resources Information Center

    Cole, Charles A.

    Described is a presentation and learning session on groundwater, which is intended to educate advisory groups interested in improving water quality decision making. Among the areas addressed are the importance of groundwater, sources of contamination, and groundwater pollution control programs. These materials are part of the Working for Clean…

  13. Methyl Tertiary Butyl Ether (MTBE) Groundwater Contamination

    NSDL National Science Digital Library

    Methyl tertiary-butyl ether (MTBE), a fuel additive, is highly mobile in groundwater, dissolving and traveling faster than the other petroleum constituents which tend to biodegrade and adsorb to soil particles. This unit will introduce the problem of pollutants as they move through the various soil layers and contaminate the groundwater and challenge the students to investigate the effects of MTBE spills in the environment by researching the available literature on fuel oxygenates and learning their mode of transport through the soil. Experimentally determined data, obtained in lab activities, will facilitate building models of the contamination process of the groundwater. Mathematics modeling will involve the use of spreadsheet analysis of real-world-data obtained online.

  14. Organic Contamination of Groundwater: A Learning Experience

    Microsoft Academic Search

    L. Stephen Lau; John F. Mink

    1987-01-01

    The discovery of contamination of the potable groundwater supply on the island of Oahu aroused public concern in the early 1980s. Pesticides used in growing pineapple and pipeline spills of aviation fuels caused several essential wells to be taken out of service. Federal and state officials took immediate action to meet the crisis and developed long-term strategies to address public

  15. Arsenic contamination in groundwater: some analytical considerations

    Microsoft Academic Search

    David G. Kinniburgh; Walter Kosmus

    2002-01-01

    For countries such as Bangladesh with a significant groundwater arsenic problem, there is an urgent need for the arsenic-contaminated wells to be identified as soon as possible and for appropriate action to be taken. This will involve the testing of a large number of wells, potentially up to 11 million in Bangladesh alone. Field-test kits offer the only practical way

  16. Probabilistic screening of ground-water contaminants

    Microsoft Academic Search

    G. M. DelVecchio; D. A. Haith

    2009-01-01

    The research described in this paper extended a deterministic screening model for ground-water contamination to include specification of variability in water flux and soil and chemical properties. Uncertainty in these parameters was characterized by independent log-normal probability distributions and a Monte Carlo simulation process was used to estimate the expected percentages of chemical mass reaching the water table. These Monte

  17. Regional assessment and mapping of groundwater vulnerability to contamination

    Microsoft Academic Search

    I. S. Zektser; A. P. Belousova; V. Yu. Dudov

    1995-01-01

    In many regions the use of groundwater for water supply is limited by the increase in contamination of aquifers. The problem of contamination requires the development of new approaches in assessing areas in which groundwater is vulnerable to contamination. A brief analysis of the present day level of methods for regional evaluation and mapping of areas in which groundwater is

  18. [Risk assessment of quaternary groundwater contamination in Beijing Plain].

    PubMed

    Guo, Gao-Xuan; Li, Yu; Xu, Liang; Li, Zhi-Ping; Yang, Qing; Xu, Miao-Juan

    2014-02-01

    Firstly, advances in investigation and evaluation of groundwater pollution in China in the last decade were presented, and several issues in the field which hinder the development of groundwater environment were pointed out. Then, four key concepts in risk assessment of groundwater pollution were briefly described with more emphasis on the difference between groundwater pollution assessment and groundwater quality assessment in this paper. After that, a method on risk assessment of groundwater pollution which included four indicators, the pollution assessment, the quality assessment, the vulnerability and the pollution load of groundwater, was presented based on the regional characteristics of Beijing Plain. Also, AHP and expert scoring method were applied to determine the weight of the four evaluation factors. Finally, the application of this method in Beijing Plain showed the area with high, relative high, medium, relative low and low risk of groundwater contamination was 1 232.1 km2, 699.3 km2, 1 951.4 km, 2 644 km2, and 133.2 km2, respectively. The study results showed that the higher risk in the western region was likely caused by the higher pollution load and its higher vulnerability, while the relatively high risk in the southeast of Beijing plain area, the Tongzhou District, is mainly caused by historical pollution sources. PMID:24812948

  19. Assessment of groundwater contamination risk using hazard quantification, a modified DRASTIC model and groundwater value, Beijing Plain, China.

    PubMed

    Wang, Junjie; He, Jiangtao; Chen, Honghan

    2012-08-15

    Groundwater contamination risk assessment is an effective tool for groundwater management. Most existing risk assessment methods only consider the basic contamination process based upon evaluations of hazards and aquifer vulnerability. In view of groundwater exploitation potentiality, including the value of contamination-threatened groundwater could provide relatively objective and targeted results to aid in decision making. This study describes a groundwater contamination risk assessment method that integrates hazards, intrinsic vulnerability and groundwater value. The hazard harmfulness was evaluated by quantifying contaminant properties and infiltrating contaminant load, the intrinsic aquifer vulnerability was evaluated using a modified DRASTIC model and the groundwater value was evaluated based on groundwater quality and aquifer storage. Two groundwater contamination risk maps were produced by combining the above factors: a basic risk map and a value-weighted risk map. The basic risk map was produced by overlaying the hazard map and the intrinsic vulnerability map. The value-weighted risk map was produced by overlaying the basic risk map and the groundwater value map. Relevant validation was completed by contaminant distributions and site investigation. Using Beijing Plain, China, as an example, thematic maps of the three factors and the two risks were generated. The thematic maps suggested that landfills, gas stations and oil depots, and industrial areas were the most harmful potential contamination sources. The western and northern parts of the plain were the most vulnerable areas and had the highest groundwater value. Additionally, both the basic and value-weighted risk classes in the western and northern parts of the plain were the highest, indicating that these regions should deserve the priority of concern. Thematic maps should be updated regularly because of the dynamic characteristics of hazards. Subjectivity and validation means in assessing the vulnerability result were also discussed. In addition, GIS technology was essential in completing the assessment work. PMID:22750168

  20. [Quantitative method of representative contaminants in groundwater pollution risk assessment].

    PubMed

    Wang, Jun-Jie; He, Jiang-Tao; Lu, Yan; Liu, Li-Ya; Zhang, Xiao-Liang

    2012-03-01

    In the light of the problem that stress vulnerability assessment in groundwater pollution risk assessment is lack of an effective quantitative system, a new system was proposed based on representative contaminants and corresponding emission quantities through the analysis of groundwater pollution sources. And quantitative method of the representative contaminants in this system was established by analyzing the three properties of representative contaminants and determining the research emphasis using analytic hierarchy process. The method had been applied to the assessment of Beijing groundwater pollution risk. The results demonstrated that the representative contaminants hazards greatly depended on different research emphasizes. There were also differences between the sequence of three representative contaminants hazards and their corresponding properties. It suggested that subjective tendency of the research emphasis had a decisive impact on calculation results. In addition, by the means of sequence to normalize the three properties and to unify the quantified properties results would zoom in or out of the relative properties characteristic of different representative contaminants. PMID:22624367

  1. Dilution and volatilization of groundwater contaminant discharges in streams.

    PubMed

    Aisopou, Angeliki; Bjerg, Poul L; Sonne, Anne T; Balbarini, Nicola; Rosenberg, Louise; Binning, Philip J

    2015-01-01

    An analytical solution to describe dilution and volatilization of a continuous groundwater contaminant plume into streams is developed for risk assessment. The location of groundwater plume discharge into the stream (discharge through the side versus bottom of the stream) and different distributions of the contaminant plume concentration (Gaussian, homogeneous or heterogeneous distribution) are considered. The model considering the plume discharged through the bank of the river, with a uniform concentration distribution was the most appropriate for risk assessment due to its simplicity and limited data requirements. The dilution and volatilization model is able to predict the entire concentration field, and thus the mixing zone, maximum concentration and fully mixed concentration in the stream. It can also be used to identify groundwater discharge zones from in-stream concentration measurement. The solution was successfully applied to published field data obtained in a large and a small Danish stream and provided valuable information on the risk posed by the groundwater contaminant plumes. The results provided by the dilution and volatilization model are very different to those obtained with existing point source models, with a distributed source leading to a larger mixing length and different concentration field. The dilution model can also provide recommendations for sampling locations and the size of impact zones in streams. This is of interest for regulators, for example when developing guidelines for the implementation of the European Water Framework Directive. PMID:25496819

  2. Estimating exposure to groundwater contaminants in karst areas

    NASA Astrophysics Data System (ADS)

    Butscher, C.

    2012-12-01

    Large multidisciplinary projects investigate health effects and environmental impacts of contamination. Such multidisciplinary projects challenge groundwater hydrologist because they demand estimations of human or environmental exposure to groundwater contaminants. But especially in karst regions, groundwater quality is subject to rapid changes resulting from highly dynamic flow systems with rapid groundwater recharge and contaminant transport in karst conduits. There is a strong need for tools that allow the quantification of the risk of contaminant exposure via the karst groundwater and its temporal variation depending on rainfall events and overall hydrological conditions. A fact that makes the assessment of contaminant exposure even more difficult is that many contaminants behave differently in the subsurface than the groundwater, because they do not dissolve and exist as a separate phase. Important examples are particulate contaminants, such as bacteria, and non-aqueous phase liquids (NAPLs), such as many organic compounds. Both are ubiquitous in the environment and have large potential for health impacts. It is known from bacterial contamination of karst springs that such contamination is strongly related to flow conditions. Bacteria, which are present at the land surface, in the soil, rock matrix or the conduit system, are immobile during base flow conditions. During storm events however, they become mobilized and are rapidly transported through the conduit flow system from sources to areas of potential exposure. As a result, bacteria concentrations that most times are low at a spring can show a high peak during storm flow. Conceptual models exist that suggest that the transport of NAPLs in karst aquifers is, just like bacterial contamination, related to flow conditions. Light NAPLs that reach the saturated zone float and accumulate on the water table; and dense NAPLs sink downward in the aquifer until they are trapped in pores, fractures and conduits where they remain stationary under base flow conditions. During storm flows, however, they can be dragged downstream or flushed as suspensions and emulsions. As a result, storm flow can send previously immobilized NAPLs to exposure zones in toxic pulses. An approach is presented to estimate the risk of contaminant exposure by bacteria and NAPLs via the groundwater under variable hydrological conditions (Butscher et al. 2011). The approach uses an indicator that is expressed as the Dynamic Vulnerability Index (DVI). This index is defined as the ratio of conduit to matrix flow contributions to spring discharge, and is calculated based on a numerical model simulating karst groundwater flow. The approach is illustrated at a test site in Switzerland, where calculated DVI was compared to the occurrence of fecal indicators during five storm flow events. Key words: karst hydrogeology; groundwater contamination; fecal indicators; NAPLs; numerical modeling References: Butscher, C. Auckenthaler, A., Scheidler, S., Huggenberger, P. (2011). Validation of a Numerical Indicator of Microbial Contamination for Karst Springs. Ground Water 49 (1), 66-76.

  3. Groundwater contamination downstream of a contaminant penetration site. I. Extension-expansion of the contaminant plume

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    2002-01-01

    This study concerns the possible use of boundary layer (BL) approach for the analysis and evaluation of contaminant transport in groundwater due to contaminant penetration into the groundwater aquifer through a site of limited size. The contaminant penetration may occur through either the upper (surface) or lower (bedrock) boundary of the aquifer. Two general cases of contaminant penetration mechanisms are considered: (1) the contaminant is transferred through an interface between a contaminating and freshwater fluid phases, and (2) the contaminant arrives at groundwater by leakage and percolation. For the purpose of BL evaluation the contaminant plume is divided into three different sections: (1) the penetration section, (2) the extension-expansion section, and (3) the spearhead section. In each section a different BL method approach yields simple analytical expressions for the description of the contaminant plume migration and contaminant transport. Previous studies of the BL method can be directly applied to the evaluation of contaminant transport at the contaminant penetration section. The present study extends those studies and concerns the contaminant transport in the two other sections, which are located downstream of the penetration section. This study shows that the contaminant concentration profiles in sections 2 and 3 incorporate two BLs: (1) an inner BL adjacent to the aquifer bottom or surface boundary, and (2) an outer BL, which develops above or below the inner one. The method developed in the present study has been applied to practical issues concerning salinity penetration into groundwater in south central Kansas.

  4. Hydrocone groundwater study delineates petroleum contamination

    SciTech Connect

    Prochaska, K.; Hartness, J. [Law Environmental, Inc., Kennesaw, GA (United States); Christenson, K. [Army Corps of Engineers, Omaha, NE (United States)

    1994-12-31

    Law Environmental, Inc., (LAW), conducted a groundwater survey at Myrtle Beach Air Force Base, South Carolina, to delineate the horizontal and vertical extent of petroleum contamination at the BX Service station. The survey was performed using the In-Situ Technology Hydrocone in conjunction with a field gas chromatograph. The Hydrocone proved to be a reliable, cost-effective method of extracting multi-depth groundwater samples without incurring the expenses associated with the installation and maintenance of monitoring wells. The process generates virtually no investigation-derived waste. The Hydrocone system consists of an elongated cylindrical steel sampler attached to drill rods on a direct push trailer mounted rig. A gas/electronic cable connects to the sampler, and a computer installed on the rig displays pressure on the tool, sampling time, and groundwater volume collected. A total of 18 groundwater samples were collected from 12 locations around the site at sampling depths of approximately 10, 20, and 30 feet below the ground surface. The Hydrocone/gas chromatograph method produced a large volume of groundwater quality data within a relatively short time interval.

  5. Groundwater contamination in Ibadan, South-West Nigeria.

    PubMed

    Egbinola, Christiana Ndidi; Amanambu, Amobichukwu Chukwudi

    2014-01-01

    Groundwater is the main source of water for domestic use in Nigeria because it is perceived to be clean. The presence of geogenic contaminants (arsenic and fluoride), and the level of awareness of their presence in groundwater in Ibadan, Nigeria was examined in this study. A total of one hundred and twenty groundwater samples were collected from hand dug wells which tap into shallow aquifers and their location taken with the aid of a GPS. The concentration of arsenic was determined by Atomic Absorption Spectrophotometry (AAS) while concentration of fluoride was determined by single beam spectrophotometer. Three hundred and fifty semi structured questionnaires were also administered within the study area to determine the level of awareness of contamination problem. Simple summary statistics including mean (m) standard deviation (s) and minimum-maximum values of the hydro-chemical data was used in the data analyses, while spatial concentrations were mapped using ArcGIS. The results showed arsenic concentration exceeding the WHO (2011) recommended concentration for drinking water in 98% and 100% of the dry and wet season samples. Concentration of Fluoride exceeded the recommended limits in 13% and 100% of the dry and wet season samples. Questionnaire analyses revealed that 85% of respondents have never tested their wells, 55% have no knowledge of geogenic contamination, while 92% never heard of arsenic or fluoride (52%). The study recommends enlightenment on geogenic contamination and testing of wells for remediation purposes. PMID:26034666

  6. Groundwater risk assessment for a Polycyclic Aromatic Hydrocarbons (PAH) contaminated

    E-print Network

    Paris-Sud XI, Université de

    2001-53 Groundwater risk assessment for a Polycyclic Aromatic Hydrocarbons (PAH) contaminated site to simulate a contamination of soils and groundwaters by PAH at a disused coke plant site were compared applying a risk assessment approach to contaminated sites, of primary importance is the evaluation

  7. groundwater nitrogen source identification and remediation

    E-print Network

    groundwater nitrogen source identification and remediation The Seymour Aquifer is a shallow aquifer operations, barnyards, septic tanks and leaking sewer systems. The goal of the Groundwater Nitrogen Source the source of nitrate nitrogen present in area groundwater and evalu- ate and demonstrate strategies

  8. Numerical simulation approaches to evaluate nitrate contamination of groundwater through leakage well in layered aquifer system

    NASA Astrophysics Data System (ADS)

    Koh, E.; Lee, E.; Lee, K.

    2013-12-01

    The layered aquifer system (i.e. perched and regional aquifers) is locally observed in Gosan area of Jeju Island, Korea due to scattered distributions of an impermeable clay layer. In the Gosan area, farming is actively performed and nitrate contamination has been frequently reported in groundwater of regional aquifer which is sole water resource in the island. Water quality of the regional groundwater is impacted by inflows of the nitrate-rich perched groundwater, which is located above the impermeable layer and directly affected by surface contaminants. A poorly grouted well penetrating the impermeable layer provides a passage of contaminated groundwater through the impermeable layer. Such a hydrogeological characteristic consequently induces nitrate contamination of the regional aquifer in this region. To quantify the inflows of the perched groundwater via leakage wells, a numerical model was developed to calculate leakage amounts of the perched groundwater into the regional groundwater. This perched groundwater leakages were applied as point and time-variable contamination sources during the solute transport simulation process for the regional aquifer. This work will provide useful information to suggest effective ways to control nitrate contamination of groundwater in the agricultural field.

  9. Anatomy of a groundwater contamination episode

    SciTech Connect

    Shechter, M.

    1985-03-01

    Using the contamination episode at Price Landfill, New Jersey, as a case study, major analytical and informational issues characterizing groundwater pollution, with special emphasis on uncertainty associated with the environmental medium, especially solute-transport processes, and the valuation of health risks, principally dose-response relationships, are addressed. Alternative approaches to modeling the physical-chemical processes are described and subsequently coupled with mortality risk predictions to derive estimates of expected pollution costs: reduced longevity (pollution damage costs) and cost of control and remedial measures (damage reductions costs.). 29 references, 1 figure, 4 tables.

  10. Hazardous waste source-reduction study with treated groundwater recycling

    SciTech Connect

    Chang, L.Y.; McCoy, B.J. (Univ. of California, Davis, CA (United States))

    1993-08-01

    A feasibility study is presented for modifying electroplating processes for source reduction. Ion exchange and reverse osmosis units are suggested to allow reclaiming and recycling of metal solutions. A particular example of water conservation in an electroplating shop is presented for the treatment and utilization of groundwater contaminated by hydrocarbon chemicals, including volatile organic compounds (VOCs) and gasoline products. Granular carbon adsorption, UV oxidation, and demineralization steps and alkalinity control measures for the groundwater are discussed. Engineering and economic analyses provide a basis for comparing alternative designs. An integrated scheme, including groundwater remediation and source reduction, is feasible for the plating shop. The removal of VOCs and demineralization of the polluted groundwater are important steps. With the integrated plan, 90% removal or recovery of heavy metals can be achieved, and water usage and wastewater can be reduced by 90%. Thus, it is feasible to prevent water pollution at the source and to recycle treated groundwater and wastewater for the manufacturing process.

  11. Groundwater dynamics and arsenic contamination in Bangladesh Charles F. Harvey a,, Khandaker N. Ashfaque a

    E-print Network

    Entekhabi, Dara

    Groundwater dynamics and arsenic contamination in Bangladesh Charles F. Harvey a,, Khandaker N March 2005; accepted 6 November 2005 Abstract Although arsenic contaminated groundwater in Bangladesh Published by Elsevier B.V. Keywords: Arsenic; Groundwater; Bangladesh; Groundwater modeling 1. Introduction

  12. Royal Swedish Academy of Sciences Assessing Groundwater Nitrate Contamination for Resource and Landscape Management

    E-print Network

    Zhang, Minghua

    and Landscape Management Author(s): Minghua Zhang, Shu Geng, K. Shawn Smallwood Reviewed work(s): Source: Ambio, and K.Shawn Smallwood Assessing GroundwaterNitrate Contamination for Resource and Landscape Management Groundwater nitrate concentrations increased and some- times exceeded public health standards during the last

  13. Groundwater contaminant plume ranking. [UMTRA Project

    SciTech Connect

    Not Available

    1988-08-01

    Containment plumes at Uranium Mill Tailings Remedial Action (UMTRA) Project sites were ranked to assist in Subpart B (i.e., restoration requirements of 40 CFR Part 192) compliance strategies for each site, to prioritize aquifer restoration, and to budget future requests and allocations. The rankings roughly estimate hazards to the environment and human health, and thus assist in determining for which sites cleanup, if appropriate, will provide the greatest benefits for funds available. The rankings are based on the scores that were obtained using the US Department of Energy's (DOE) Modified Hazard Ranking System (MHRS). The MHRS and HRS consider and score three hazard modes for a site: migration, fire and explosion, and direct contact. The migration hazard mode score reflects the potential for harm to humans or the environment from migration of a hazardous substance off a site by groundwater, surface water, and air; it is a composite of separate scores for each of these routes. For ranking the containment plumes at UMTRA Project sites, it was assumed that each site had been remediated in compliance with the EPA standards and that relict contaminant plumes were present. Therefore, only the groundwater route was scored, and the surface water and air routes were not considered. Section 2.0 of this document describes the assumptions and procedures used to score the groundwater route, and Section 3.0 provides the resulting scores for each site. 40 tabs.

  14. Potassium ferrate treatment of RFETS` contaminated groundwater

    SciTech Connect

    NONE

    1995-01-01

    The potassium ferrate treatment study of Rocky Flats Environmental Technology Site (RFETS) groundwater was performed under the Sitewide Treatability Studies Program (STSP). This study was undertaken to determine the effectiveness of potassium ferrate in a water treatment system to remove the contaminants of concern (COCS) from groundwater at the RFETS. Potassium ferrate is a simple salt where the iron is in the plus six valence state. It is the iron at the plus six valence state (Fe {sup +6}) that makes it an unique water treatment chemical, especially in waters where the pH is greater than seven. In basic solutions where the solubility of the oxides/hydroxides of many of the COCs is low, solids are formed as the pH is raised. By using ferrate these solids are agglomerated so they can be effectively removed by sedimentation in conventional water treatment equipment. The objective of this study was to determine the quality of water after treatment with potassium ferrate and to determine if the Colorado Water Quality Control Commission (CWQCC) discharge limits for the COCs listed in Table 1.0-1 could be met. Radionuclides in the groundwater were of special concern.

  15. Tracing groundwater recharge in the San Luis Valley, Colorado: Groundwater contamination susceptibility in an agricultural watershed

    NASA Astrophysics Data System (ADS)

    Patel, Tanya; Hindshaw, Ruth; Singer, Michael

    2015-04-01

    Water is a vital resource in any agricultural watershed, yet in the arid western United States farming practices threaten the quality and availability of groundwater. This is a pressing concern in the San Luis Valley, southern Colorado, where agriculture comprises 30% of the local economy, and employs over half the valley population. Although 54 % of the water used for irrigation is surface water, farmers do not usually apply this water directly to their fields. Instead, the water is often diverted into pits which recharge the aquifer, and the water is subsequently pumped during the following irrigation season. The Rio Grande Water Conservation District recognises that recharge to the unconfined aquifer has been outpaced by commercial irrigation for at least four decades, resulting in a decline in groundwater levels. Recycled irrigation water, and leakage from unlined canals now represent the greatest recharge contribution to the unconfined aquifer in this region. This makes the shallow groundwater particularly susceptible to agricultural contamination. The purpose of this study is to assess groundwater contamination in the unconfined and upper confined aquifers of the San Luis Valley, which are the most susceptible to contamination due to their close proximity to the surface. Although concentrations of potentially harmful contaminants from agricultural runoff are regularly monitored, the large spatial and temporal fluctuations in values make it difficult to determine long-term trends. We have analysed ?18O, ?2H and major-ion chemistry of 57 groundwater, stream and precipitation samples, collected in June 2014, and interpreted them alongside regional stream flow data and groundwater levels. This will allow us to study the seasonality and locality of groundwater recharge to provide greater insight into the watershed's potential for pollution. A groundwater vulnerability assessment was performed using the model DRASTIC (Depth to water, Recharge, Aquifer media, Soil media, Topography, Influence of the vadose zone and hydraulic Conductivity). Each variable is assigned a weighting and rating, which provides a quantitative assessment of an area's pollution potential. Using this method of investigation, the groundwater vulnerability map produced classifies 5% of the area as having low pollution potential, 34% as having moderate pollution potential, and 61% as having high pollution potential. The groundwater vulnerability map may be used to predict the variation in agricultural contaminant concentrations in the unconfined aquifer. Major ion analyses revealed that nitrate concentrations are highly variable, varying between 0.435 and 949?M/L, and exceed the EPA maximum contaminant level at four sites. The spatial variability in nitrate concentrations, as well as sulphate and phosphate concentrations, is much greater than the differences predicted by the model. This suggests that this variability is not a result of differences in the hydrogeology between sites, but instead may be related to individual farm practices or a result of point sources such as animal waste, septic tanks and sewage release. Understanding the impact of commercial irrigation on groundwater quality and availability is vital for developing effective strategies to stabilise groundwater levels, and protect the farmers and local population that rely on this water.

  16. Arsenic contaminated groundwater and its treatment options in Bangladesh.

    PubMed

    Jiang, Jia-Qian; Ashekuzzaman, S M; Jiang, Anlun; Sharifuzzaman, S M; Chowdhury, Sayedur Rahman

    2013-01-01

    Arsenic (As) causes health concerns due to its significant toxicity and worldwide presence in drinking water and groundwater. The major sources of As pollution may be natural process such as dissolution of As-containing minerals and anthropogenic activities such as percolation of water from mines, etc. The maximum contaminant level for total As in potable water has been established as 10 µg/L. Among the countries facing As contamination problems, Bangladesh is the most affected. Up to 77 million people in Bangladesh have been exposed to toxic levels of arsenic from drinking water. Therefore, it has become an urgent need to provide As-free drinking water in rural households throughout Bangladesh. This paper provides a comprehensive overview on the recent data on arsenic contamination status, its sources and reasons of mobilization and the exposure pathways in Bangladesh. Very little literature has focused on the removal of As from groundwaters in developing countries and thus this paper aims to review the As removal technologies and be a useful resource for researchers or policy makers to help identify and investigate useful treatment options. While a number of technological developments in arsenic removal have taken place, we must consider variations in sources and quality characteristics of As polluted water and differences in the socio-economic and literacy conditions of people, and then aim at improving effectiveness in arsenic removal, reducing the cost of the system, making the technology user friendly, overcoming maintenance problems and resolving sludge management issues. PMID:23343979

  17. Potential of groundwater contamination by polybrominated diphenyl ethers (PBDEs) in a sensitive bedrock aquifer (Canada)

    NASA Astrophysics Data System (ADS)

    Levison, Jana; Novakowski, Kent; Reiner, Eric J.; Kolic, Terry

    2012-03-01

    It is necessary to understand the presence, movement, and persistence of contaminants in aquifers to develop adequate groundwater protection plans. Fractured bedrock aquifers with thin overburden cover are very sensitive to contamination, and little is known about transport processes from the ground surface to depth in this setting. This study was undertaken to investigate the potential of groundwater contamination by polybrominated diphenyl ethers (PBDEs), which are flame retardants, in a natural fractured bedrock aquifer in Canada proven to be sensitive to contamination. PBDEs, which had not been previously measured in groundwater in detail, were detected in the study aquifer at concentrations greater than those observed in surface-water bodies. Potential sources include manure, septic tanks, and the atmosphere. From this scoping study, it is evident that additional surveys of PBDE concentrations in groundwater are warranted, especially in settings with high potential source concentrations coupled with sensitive aquifers.

  18. Arsenic Contamination of Groundwater in Bangladesh and Its Remedial Measures

    Microsoft Academic Search

    M. Habibur Rahman; M. Mafizur Rahman; Chiho Watanabe; Kazuo Yamamoto

    resently groundwater contamination by arsenic (As) is a major concern in Bangladesh where about 97% of the total rural population depend on tube-wells for drinking water, which is bacteriologically safe to drink. Arsenic was first detected in groundwater in the west of Bangladesh in 1993 following reports of extensive contamination of water supplies in the adjoining areas of India and

  19. Groundwater contamination near the Hoe Creek UCG experiments

    Microsoft Academic Search

    F. T. Wang; S. W. Mead; D. H. Stuermer

    1981-01-01

    It has been shown that underground coal gasification (UCG) may introduce a broad range of residual gasification products into the groundwater of a coal aquifer. Sorption of many contaminants by the coal itself is an important factor in restricting the migration of these contaminants in the groundwater. However, our field studies, conducted at Lawrence Livermore National Laboratory's Hoe Creek site,

  20. Phytoremediation of Arsenic-Contaminated Groundwater by the Arsenic Hyperaccumulating Fern Pteris vittata L

    Microsoft Academic Search

    S. Tu; Lena Q. Ma; Abioye O. Fayiga; Edward J. Zillioux

    2004-01-01

    Arsenic concentrations in a much larger fraction of U.S. groundwater sources will exceed the maximum contaminant limit when the new 10 ?g L EPA standard for drinking water takes effect in 2006. Thus, it is important to develop remediation technologies that can meet this new standard. Phytoremediation of arsenic-contaminated groundwater is a relatively new idea. In this research, an arsenic-hyperaccumulating

  1. Evaluation of intrinsic vulnerability to nitrate contamination of groundwater: appropriate fertilizer application management

    Microsoft Academic Search

    Yoshio Mishima; Masayuki Takada; Rie Kitagawa

    2011-01-01

    In agricultural areas, fertilizer application is the main source of nitrate contamination of groundwater. To develop fertilizer\\u000a management strategies to combat this problem, arable land in Hokkaido, Japan was evaluated using geographic information system\\u000a techniques for intrinsic groundwater vulnerability to nitrate contamination. The DRASTIC method was modified to adapt it to\\u000a the Hokkaido environment and used for the evaluation. Of

  2. Modeling Groundwater-Surface Water Interaction and Contaminant Transport of Chlorinated Solvent Contaminated Site

    NASA Astrophysics Data System (ADS)

    Yimer Ebrahim, Girma; Jonoski, Andreja; van Griensven, Ann; Dujardin, Juliette; Baetelaan, Okke; Bronders, Jan

    2010-05-01

    Chlorinated-solvent form one of the largest groups of environmental chemicals. Their use and misuse in industry have lead to a large entry of these chemicals into the environment, resulting in widespread dissemination and oftentimes environmental contamination. Chlorinated solvent contamination of groundwater resources has been widely reported. For instance, there has been much interest in the assessment of these contaminant levels and their evolutions with time in the groundwater body below the Vilvoorde-Machelen industrial area (Belgium). The long industrial history of the area has lead to complex patterns of pollution from multiple sources and the site has been polluted to the extent that individual plumes are not definable any more. Understanding of groundwater/surface water interaction is a critical component for determining the fate of contaminant both in streams and ground water due to the fact that groundwater and surface water are in continuous dynamic interaction in the hydrologic cycle. The interaction has practical consequences in the quantity and quality of water in either system in the sense that depletion and/or contamination of one of the system will eventually affect the other one. The transition zone between a stream and its adjacent aquifer referred to as the hyporheic zone plays a critical role in governing contaminant exchange and transformation during water exchange between the two water bodies. The hyporheic zone of Zenne River ( the main receptor ) is further complicated due to the fact that the river banks are artificially trained with sheet piles along its reach extending some 12 m below the surface. This study demonstrates the use of MODFLOW, a widely used modular three-dimensional block-centred finite difference, saturated flow model for simulating the flow and direction of movement of groundwater through aquifer and stream-aquifer interaction and the use of transport model RT3D, a three-dimensional multi-species reactive transport model capable of incorporating multiple chemical and biological reactions to model the movement and chemical alteration of chlorinated solvents as they move with groundwater through the subsurface and reach to the surface water of the Zenne River . Keywords: MODFLOW, RT3D, Chlorinated-solvent; groundwater/surface water interaction ACKNOWLEDGEMENT The authors would like to thank the EU/FP7 AQUAREHAB Project for the financial support.

  3. Assessing Groundwater Contamination Vulnerability at Public Water Supply Wells in California

    Microsoft Academic Search

    J. E. Moran; B. Hudson; B. P. Dooher; R. Leif; G. F. Eaton; L. Davisson

    2001-01-01

    The California Aquifer Susceptibility project, sponsored by the California State Water Resources Control Board, uses a probabilistic approach to assess the vulnerability of public water supply wells to contamination by anthropogenic compounds. Sources of contamination to groundwater occur near the earth's surface, and have been present mostly since WWII. Therefore, wells that receive water that has recharged in the recent

  4. Microbiological analysis of multi-level borehole samples from a contaminated groundwater system

    Microsoft Academic Search

    R. W. Pickup; G. Rhodes; M. L. Alamillo; H. E. H. Mallinson; S. F. Thornton; D. N. Lerner

    2001-01-01

    A range of bacteriological, geochemical process-related and molecular techniques have been used to assess the microbial biodegradative potential in groundwater contaminated with phenol and other tar acids. The contaminant plume has travelled 500 m from the pollutant source over several decades. Samples were obtained from the plume using a multi-level sampler (MLS) positioned in two boreholes (boreholes 59 and 60)

  5. Using Pre-Modeled Scenarios to Estimate Groundwater VOC Concentrations Resulting from Vadose Zone Sources

    SciTech Connect

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

    2014-04-28

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

  6. Sources of Water Surface water and groundwater are present throughout

    E-print Network

    MacAdam, Keith

    miles. Surface water occurs as rivers, streams, ponds, lakes, and wetlands. Ground- water occurs public supply systems provide water for 80 percent of the population. Water Contamination SurfaceSources of Water Surface water and groundwater are present throughout Kentucky's 39,486 square

  7. Emerging policies to control nonpoint source pollution of groundwater

    NASA Astrophysics Data System (ADS)

    Harter, T.

    2014-12-01

    Water quality impairment is among the highest ranking public issues of concern in the developed world. While, in Europe and North America, many water quality programs have been put in place over the past half century, regulators difficulties tackling the geographically most widespread water quality degradation in these regions: pollution of groundwater (as opposed to surface water) from diffuse sources (as opposed to point sources), including contamination with nitrate (affecting drinking water supplies in rural areas and at the rural-urban interface) and salinity (affecting irrigation water quality). Other diffuse pollution contaminants include pesticides and emerging contaminants (e.g., antibiotics and pathogens from animal farming). The geographic and hydrologic characteristics of nonpoint source pollution of groundwater are distinctly different from other types of water pollution: individually liable sources are contiguous across the landscape, and internally heterogeneous in space and time. On annually aggregated time scales (most relevant to groundwater), sources are continuously emitting pollution, while pollution levels typically do not exceed MCLs by less than a factor 2. An analysis of key elements of existing water pollution policies to control groundwater pollution from diffuse sources demonstrates the lack of both, science and institutional capacity, while existing point-source approaches cannot be applied toward the control of diffuse pollution to groundwater. For the latter, a key to a successful policy is a tiered, three-way monitoring program based on proxy compliance metrics instead of direct measurement of pollutant discharge, research linking actual pollutant discharges to proxy metrics, and long-term regional groundwater monitoring to establish large scale, long-term trends. Several examples of emerging regulations from California and the EU are given to demonstrate these principles.

  8. Risk Assessment of Groundwater Contamination: A Multilevel Fuzzy Comprehensive Evaluation Approach Based on DRASTIC Model

    PubMed Central

    Zhang, Yan; Zhong, Ming

    2013-01-01

    Groundwater contamination is a serious threat to water supply. Risk assessment of groundwater contamination is an effective way to protect the safety of groundwater resource. Groundwater is a complex and fuzzy system with many uncertainties, which is impacted by different geological and hydrological factors. In order to deal with the uncertainty in the risk assessment of groundwater contamination, we propose an approach with analysis hierarchy process and fuzzy comprehensive evaluation integrated together. Firstly, the risk factors of groundwater contamination are identified by the sources-pathway-receptor-consequence method, and a corresponding index system of risk assessment based on DRASTIC model is established. Due to the complexity in the process of transitions between the possible pollution risks and the uncertainties of factors, the method of analysis hierarchy process is applied to determine the weights of each factor, and the fuzzy sets theory is adopted to calculate the membership degrees of each factor. Finally, a case study is presented to illustrate and test this methodology. It is concluded that the proposed approach integrates the advantages of both analysis hierarchy process and fuzzy comprehensive evaluation, which provides a more flexible and reliable way to deal with the linguistic uncertainty and mechanism uncertainty in groundwater contamination without losing important information. PMID:24453883

  9. Soil and groundwater contamination by oil spills; problems and remedies

    Microsoft Academic Search

    R. Vanloocke; R. De Borger; J. P. Voets; W. Verstraete

    1975-01-01

    Large scale transport and storage of hydrocarbons constitute a threat to the soil ecosystems and to the ground?water reserves. To clean?up oil spilled on soils or polluting groundwaters, one has either to remove mechanically the soil impregnated with oil or to collect and remove by pumping the contaminated groundwater reserves. A third and ultimately more complete clean?up method consists of

  10. APPLICABILITY OF UV/OXIDATION TECHNOLOGIES TO TREAT CONTAMINATED GROUNDWATER

    EPA Science Inventory

    This paper presents information useful in evaluating the applicability of UV/Oxidation treatment technologies for groundwater contaminated with organics. he information presented includes a description of the technologies, factors affecting the technologies, and results from two ...

  11. FEASIBILITY OF USING FIBER OPTICS FOR MONITORING GROUNDWATER CONTAMINANTS

    EPA Science Inventory

    The report contains the results of the initial feasibility study for a research program undertaken to develop the technology needed to use fiber optics for monitoring groundwater contaminants. The technology appears especially well suited to the requirements of detection monitori...

  12. A multilayer groundwater sampler for characterizing contaminant plumes. Final report

    SciTech Connect

    Kaplan, E.; Heiser, J.

    1992-12-18

    This final report describes activities related to the design and initial demonstration of a passive multilayer groundwater sampling system. The apparatus consists of remotely controlled cylinders filled with deionized water which are connected in tandem. Vertical fine structure of contaminants are easily defined. Using the apparatus in several wells may lead to three dimensional depictions of groundwater contamination, thereby providing the information necessary for site characterization and remediation.

  13. A multilayer groundwater sampler for characterizing contaminant plumes

    SciTech Connect

    Kaplan, E.; Heiser, J.

    1992-12-18

    This final report describes activities related to the design and initial demonstration of a passive multilayer groundwater sampling system. The apparatus consists of remotely controlled cylinders filled with deionized water which are connected in tandem. Vertical fine structure of contaminants are easily defined. Using the apparatus in several wells may lead to three dimensional depictions of groundwater contamination, thereby providing the information necessary for site characterization and remediation.

  14. Investigating a Real-Life Groundwater Contamination Event

    NSDL National Science Digital Library

    Peter Riemersma

    This assignment is designed as a final project for students in my undergraduate 3 credit non lab elective geohydrology course. Students work in pairs to analyze an actual, local contaminated site (Delphi) and use raw data from consulting reports (boring logs, water levels, chemical water analyses) to prepare a geologic cross-section, water table map and contaminant plume map. Students are assigned different lines of cross section, water level dates and contaminant types. Students examine the variety of different figures and maps to better characterize hydrogeologic and water quality conditions over the entire site and answer some assigned questions. This project is an opportunity for students to apply skills they learned in the course (contouring, groundwater flow) to investigate an existing groundwater contamination event. It also provides the kind of "practical" experience the students can highlight in a job interview. Key words: Groundwater contamination, case study, TCE

  15. Estimating groundwater vulnerability to nonpoint source pollution from nitrates and pesticides on a regional scale

    Microsoft Academic Search

    BERNARD ENGEL; KUMAR NAVULUR; BRIAN COOPER; LEIGHANNE HAHN

    One of the major sources of groundwater pollution in the midwest United States is nonpoint source (NPS) pollution resulting from agricultural production. GIS-based techniques were developed and tested to provide groundwater vulnerability maps to agricultural NPS pollution (pesticides and nitrate) for regional areas. The results were evaluated within the GIS using nitrate and pesticide contamination in well water data to

  16. Determination of protection zones for Dutch groundwater wells against virus contamination -uncertainty and

    E-print Network

    Hassanizadeh, S. Majid

    Determination of protection zones for Dutch groundwater wells against virus contamination calculated that allow protection against virus contamination to the level that the infection risk of 1024 per unsaturated conditions. Key words | contamination, groundwater, protection, sensitivity, uncertainty, virus

  17. Nitrate contamination of groundwater in the catchment of Gocza?kowice reservoir

    NASA Astrophysics Data System (ADS)

    Czekaj, Joanna; Witkowski, Andrzej J.

    2014-05-01

    Gocza?kowice dammed reservoir (area - 26 km2 , volume - 100 million m3 at a typical water level) is a very important source of drinking water for Upper Silesian agglomeration. At the catchment of the reservoir there are many potential sources of groundwater pollution (agriculture, bad practices in wastewater management, intensive fish farming). Thus local groundwater contamination, mainly by nitrogen compounds. The paper presents groundwater monitoring system and preliminary results of the research carried on at Gocza?kowice reservoir and its catchment in 2010 - 2014 within the project "Integrated system supporting management and protection of dammed reservoir (ZiZoZap)'. The main objective for hydrogeologists in the project is to assess the role of groundwater in total water balance of the reservoir and the influence of groundwater on its water quality. During research temporal variability of groundwater - surface water exchange has been observed. Monitoring Network of groundwater quality consists of 22 observation wells (nested piezometers included) located around the reservoir - 13 piezometers is placed in two transects on northern and southern shore of reservoir. Sampling of groundwater from piezometers was conducted twice - in autumn 2011 and spring 2012. Maximum observed concentrations of nitrate, nitrite and ammonium were 255 mg/L, 0,16 mg/L and 3,48 mg/L, respectively. Surface water in reservoir (8 points) has also been sampled. Concentrations of nitrate in groundwater are higher than in surface water. Nitrate and ammonium concentrations exceeding standards for drinking water were reported in 18% and 50% of monitored piezometers, respectively. High concentration of nitrate (exceeding more than 5 times maximal admissible concentration) have been a significant groundwater contamination problem in the catchment of the reservoir. Periodically decrease of surface water quality is possible. Results of hydrogeological research indicate substantial spatial variability in concentrations of nitrogen compounds in groundwater of the Quaternary aquifer. To determine an origin of nitrate in groundwater the study of isotopic composition of nitrogen and oxygen in nitrate was conducted.

  18. Impacts of arsenic contamination in groundwater: case study of some villages in Bangladesh

    Microsoft Academic Search

    Nurun Nahar

    2009-01-01

    The contamination of groundwater in Bangladesh by arsenic is a widespread and serious environmental problem, affecting mainly\\u000a the rural population who rely extensively on groundwater for drinking and cooking. The study conducted survey work in a few\\u000a affected villages of the Northwest region in Bangladesh. The household survey gathered information on the respondents (affected\\u000a by arsenic) water usage and sources,

  19. Viability of longitudinal trenches for capturing contaminated groundwater.

    PubMed

    Hudak, Paul F

    2010-04-01

    Using a groundwater flow and mass transport model, this study compared the capability of trenches with permeable backfill for capturing hypothetical contaminant plumes in homogeneous and heterogeneous unconfined aquifers. Longitudinal (parallel to groundwater flow), as well as conventional transverse (perpendicular to groundwater flow) trench configurations were considered. Alternate trench configurations intercepted the leading tip of an initial contaminant plume and had identical length, equal to the cross-gradient width of the plume. A longitudinal trench required 31% less time than its transverse counterpart to remediate a homogeneous aquifer. By contrast, in simulated heterogeneous aquifers, longitudinal remediation timeframes ranged from 41% less to 33% more than transverse trenches. Results suggest that longitudinal trenches may be a viable alternative for narrow contaminant plumes under low-groundwater velocity conditions, but may be impractical for plumes with wide leading tips, or in complex heterogeneous aquifers with divergent flow. PMID:20237910

  20. A Contamination Vulnerability Assessment for the Santa Clara and San Mateo County Groundwater Basins

    SciTech Connect

    Moran, J E; Hudson, G B; Eaton, G F; Leif, R

    2004-01-06

    In response to concerns expressed by the California Legislature and the citizenry of the State of California, the State Water Resources Control Board (SWRCB), implemented a program to assess groundwater quality, and provide a predictive capability for identifying areas that are vulnerable to contamination. The program was initiated in response to concern over public supply well closures due to contamination by chemicals such as MtBE from gasoline, and solvents from industrial operations. As a result of this increased awareness regarding groundwater quality, the Supplemental Report of the 1999 Budget Act mandated the SWRCB to develop a comprehensive ambient groundwater-monitoring plan, and led to the initiation of the Ambient Groundwater Monitoring and Assessment (GAMA) Program. The primary objective of the GAMA Program is to assess the water quality and to predict the relative susceptibility to contamination of groundwater resources throughout the state of California. Under the GAMA program, scientists from Lawrence Livermore National Laboratory (LLNL) collaborate with the SWRCB, the U.S. Geological Survey, the California Department of Health Services (DHS), and the California Department of Water Resources (DWR) to implement this groundwater assessment program. In 2001 and 2002, LLNL carried out this vulnerability study in the groundwater basins of Santa Clara County and San Mateo County, located to the south of the city of San Francisco. The goal of the study is to provide a probabilistic assessment of the relative vulnerability of groundwater used for the public water supply to contamination from surface sources. This assessment of relative contamination vulnerability is made based on the results of two types of analyses that are not routinely carried out at public water supply wells: ultra low-level measurement of volatile organic compounds (VOCs), and groundwater age dating (using the tritium-helium-3 method). In addition, stable oxygen isotope measurements help determine the recharge water source location. Interpreted together, and in the context of existing water quality and hydrogeologic data, these observable parameters help define the flow field of a groundwater basin, and indicate the degree of vertical communication between near-surface sources (or potential sources) of contamination, and deeper groundwater pumped at high capacity production wells.

  1. Probabilistic assessment of ground-water contamination. 1: Geostatistical framework

    Microsoft Academic Search

    Christopher A. Rautman; Jonathan D. Istok

    1996-01-01

    Characterizing the extent and severity of ground-water contamination at waste sites is expensive and time-consuming. A probabilistic approach, based on the acceptance of uncertainty and a finite probability of making classification errors (contaminated relative to a regulatory threshold vs. uncontaminated), is presented as an alternative to traditional site characterization methodology. The approach utilizes geostatistical techniques to identify and model the

  2. SUMMARY OF WATERBORNE ILLNESS TRANSMITTED THROUGH CONTAMINATED GROUNDWATER

    EPA Science Inventory

    The use of contaminated, untreated or inadequately treated groundwater was responsible for 51 percent of all waterborne outbreaks and 40 percent of all waterborne illness reported in the United States during the period 1971-82. Contaminated, untreated or inadequately disinfected ...

  3. Environmental contamination of groundwater in the Gaza Strip

    NASA Astrophysics Data System (ADS)

    Al-Agha, M. R.

    1995-03-01

    Environmental problems of groundwater contamination in the Gaza Strip are summarized in this paper. The Gaza Strip is a very narrow and highly populated area along the coast of the Mediterranean Sea (360 km2). Human activities greatly threaten the groundwater resources in the area, while the unconfined nature of some parts of the coastal main aquifer favors groundwater contamination. Recent investigations show contamination of the aquifer with organic substances from detergents, agrochemicals, sewage (cesspools), and waste degradation. These effects enhance each other because there is no recycling industry, sewage system, or any type of environmental protection management at present. Inorganic contamination results from overpumping, which increases the salinity of the groundwater. Seawater intrusion also increases the salinity of the groundwater that are used for drinking and agricultural purposes. Consequently, at present about 80 percent of the groundwater in the Gaza Strip is unfit for both human and animal consumption. Solutions are very urgently needed for these problems in order to prevent the spread of dangerous diseases.

  4. Groundwater contamination. Volume 2: Management, containment, risk assessment and legal issues

    SciTech Connect

    Rail, C.D.

    2000-07-01

    This book explains in a comprehensive way the sources for groundwater contamination, the regulations governing it, and the technologies for abating it. Volume 2 discusses aquifer management, including technologies to control and stabilize multiple influxes into the water table. This volume outlines strategies for stormwater control and groundwater restoration and presents numerous case histories of site analysis and remediation based on DOE and state documents. Among the many new features of this edition are a full discussion of risk assessment, the preparation of groundwater protection plans, and references linking the text to over 2,300 water-related Web sites.

  5. Probabilistic screening tool for ground-water contamination assessment

    SciTech Connect

    Hamed, M.M.; Conte, J.P.; Bedient, P.B. [Rice Univ., Houston, TX (United States)

    1995-11-01

    This paper presents a methodology for assessing the effects of source-, chemical-, and aquifer-related parameter uncertainty on the response of a semianalytical transport model using first- and second-order reliability methods. A probabilistic model is developed by coupling the deterministic transport model with a general-purpose probability analysis program. Ground-water contamination risk is addressed by evaluating the probability that a given contaminant exceeds the regulated standards at a well downgradient from a waste source. The general applicability of the methodology is demonstrated on two simple hypothetical case studies of transport of nonreactive and reactive solutes in the subsurface. Sensitivities of the probabilistic outcome to the basic uncertainties in the input random variables are provided through importance factors. The reliability-method results are checked against those obtained using the classical Monte Carlo--simulation method, and the results are in good agreement except for very low probability events in which the reliability methods provide accurate results much more efficiently than the Monte Carlo method. The need for a careful trade-off analysis between accuracy and computer time is highlighted.

  6. Bioremediation of TCE contaminated groundwater using aerobic bioaugmentation: Field demonstration

    SciTech Connect

    Bourquin, A.W.; Mosteller, D.C.; Olsen, R.L.; Smith, M.J. [Camp Dresser and McKee Inc., Denver, CO (United States); Reardon, K.F. [Colorado State Univ., Fort Collins, CO (United States)

    1996-12-31

    Groundwater throughout the central district of Wichita, Kansas, is contaminated with trichloroethene (TCE) and dichloroethene (DCE). A field study demonstrated the feasibility of aerobic bioremediation using bioaugmentation with Burkholderia cepacia PR1{sub 301} to degrade the chlorinated aliphatic hydrocarbons (CAHs). The CAH biodegradative capabilities of the strain are unique because it is constitutive for toluene ortho-monooxygenase (TOM). Field trials were conducted with PR1 grown to high cell densities and high TOM activity and continuously added to the groundwater with oxygen through an injection well. Monitoring points were installed 5 days hydraulic flow upgradient and 2, 5, 10, and 15 days downgradient from the injection well. A bromide groundwater tracer study was used to determine hydraulic flow, flowpath and retardation of oxygen, contaminants and microorganisms. Oxygen was retarded in the soil formation by 60 days but this could not be attributed to reduced constituents or microbial activity. The field test was amended to determine the feasibility of a biological barrier which would effectively remove all contaminants from the groundwater flowing through it. The injection well simulated the trench with an average 250 ppb total CAHs moving through the system. The microorganisms degraded to non-detect all contaminants in the aerobic system within 24 hours following injection and maintained that level for 4 days. Total mass of contaminants degraded during the test period is estimated at 10.23 mg, or 94.5 {micro}g/L/h. The test system formed an effective removal barrier for contamination allowing clean groundwater to flow downgradient of the injection well. This was the first demonstration that bioaugmentation could effectively degrade CAHs using a laboratory developed strain. CDM is designing an in-ground trench for maintaining a biological barrier to prevent further migration of groundwater contaminates at the Gilbert-Mosley site.

  7. Groundwater contamination downstream of a contaminant penetration site. II. Horizontal penetration of the contaminant plume

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    2002-01-01

    Part I of this study (Rubin, H.; Buddemeier, R.W. Groundwater Contamination Downstream of a Contaminant Penetration Site Part 1: Extension-Expansion of the Contaminant Plume. J. of Environmental Science and Health Part A (in press).) addressed cases, in which a comparatively thin contaminated region represented by boundary layers (BLs) developed within the freshwater aquifer close to contaminant penetration site. However, at some distance downstream from the penetration site, the top of the contaminant plume reaches the top or bottom of the aquifer. This is the location of the "attachment point," which comprises the entrance cross section of the domain evaluated by the present part of the study. It is shown that downstream from the entrance cross section, a set of two BLs develop in the aquifer, termed inner and outer BLs. It is assumed that the evaluated domain, in which the contaminant distribution gradually becomes uniform, can be divided into two sections, designated: (a) the restructuring section, and (b) the establishment section. In the restructuring section, the vertical concentration gradient leads to expansion of the inner BL at the expense of the outer BL, and there is almost no transfer of contaminant mass between the two layers. In the establishment section, each of the BLs occupies half of the aquifer thickness, and the vertical concentration gradient leads to transfer of contaminant mass from the inner to the outer BL. By use of BL approximations, changes of salinity distribution in the aquifer are calculated and evaluated. The establishment section ends at the uniformity point, downstream from which the contaminant concentration profile is practically uniform. The length of the restructuring section, as well as that of the establishment section, is approximately proportional to the aquifer thickness squared, and is inversely proportional to the transverse dispersivity. The study provides a convenient set of definitions and terminology that are helpful in visualizing the gradual development of uniform contaminant concentration distribution in an aquifer subject to contaminant plume penetration. The method developed in this study can be applied to a variety of problems associated with groundwater quality, such as initial evaluation of field data, design of field data collection, the identification of appropriate boundary conditions for numerical models, selection of appropriate numerical modeling approaches, interpretation and evaluation of field monitoring results, etc.

  8. Enhanced detection of groundwater contamination from a leaking waste disposal site by microbial community profiles

    NASA Astrophysics Data System (ADS)

    Mouser, Paula J.; Rizzo, Donna M.; Druschel, Gregory K.; Morales, Sergio E.; Hayden, Nancy; O'Grady, Patrick; Stevens, Lori

    2010-12-01

    Groundwater biogeochemistry is adversely impacted when municipal solid waste leachate, rich in nutrients and anthropogenic compounds, percolates into the subsurface from leaking landfills. Detecting leachate contamination using statistical techniques is challenging because well strategies or analytical techniques may be insufficient for detecting low levels of groundwater contamination. We sampled profiles of the microbial community from monitoring wells surrounding a leaking landfill using terminal restriction fragment length polymorphism (T-RFLP) targeting the 16S rRNA gene. Results show in situ monitoring of bacteria, archaea, and the family Geobacteraceae improves characterization of groundwater quality. Bacterial T-RFLP profiles showed shifts correlated to known gradients of leachate and effectively detected changes along plume fringes that were not detected using hydrochemical data. Experimental sediment microcosms exposed to leachate-contaminated groundwater revealed a shift from a ?-Proteobacteria and Actinobacteria dominated community to one dominated by Firmicutes and ?-Proteobacteria. This shift is consistent with the transition from oxic conditions to an anoxic, iron-reducing environment as a result of landfill leachate-derived contaminants and associated redox conditions. We suggest microbial communities are more sensitive than hydrochemistry data for characterizing low levels of groundwater contamination and thus provide a novel source of information for optimizing detection and long-term monitoring strategies at landfill sites.

  9. The Groundwater Foundation

    NSDL National Science Digital Library

    The Groundwater Foundation is a non-profit organization dedicated to educating and motivating people to care for and about groundwater. The section Groundwater Basics contains numerous information on groundwater issues, including the following subjects: what is groundwater; how much do we depend on groundwater; groundwater protection, hydrologic cycle, contamination and concerns, sources of groundwater contamination, wells and how they work, ten ways to help conserve and protect groundwater, groundwater ABCs - a glossary of groundwater-related terminology, and source water assessment and protection guide and training materials. Also of interest are kids and youth sections with activities and games, as well as a listing of the foundation's publications and events.

  10. REMOVAL OF AGRICULTURAL CONTAMINANTS FROM GROUNDWATER

    EPA Science Inventory

    As analytical testing of community and individual homeowner wells has intensified, more drinking water contamination has been identified. In some instances, this contamination can be attributed to agricultural practices. Of special concern are those locations where no community t...

  11. Assessing Ground-Water Vulnerability to Contamination: Providing Scientifically Defensible Information for Decision Makers

    NSDL National Science Digital Library

    Focazio, Michael J.

    A new report from the US Geological Survey has been made available entitled Assessing Ground-Water Vulnerability to Contamination: Providing Scientifically Defensible Information for Decision Makers. The report provides a look at the common approaches used to scientifically determine the factors controlling the vulnerability of groundwater resources to contamination. The introduction states that it also discusses the strengths and weaknesses of the various approaches as sources of scientifically defensible information for the water-resource management decision-making process. Viewed online or downloadable, the freely accessed publication covers everything from methods and examples to conclusions and references.

  12. Development of Chemical Indicators of Groundwater Contamination Near the Carcass Burial Site

    NASA Astrophysics Data System (ADS)

    Kim, H.; Choi, J.; Kim, M.; Choi, J.; Lee, M.; Lee, H.; Jeon, S.; Bang, S.; Noh, H.; Yoo, J.; Park, S.; Kim, H.; Kim, D.; Lee, Y.; Han, J.

    2011-12-01

    A serious outbreak of foot and mouth disease (FMD) and avian influenza (AI) led to the culling of millions of livestock in South Korea from late 2010 to earlier 2011. Because of the scale of FMD and AI epidemic in Korea and rapid spread of the diseases, mass burial for the disposal of carcass was conducted to halt the outbreak. The improper construction of the burial site or inappropriate management of the carcass burial facility can cause the contamination of groundwater mainly due to the discharges of leachate through the base of disposal pit. The leachate from carcass burial contains by products of carcass decay such as amino acids, nitrate, ammonia and chloride. The presence of these chemical components in groundwater can be used as indicators demonstrating contamination of groundwater with leachate from carcass. The major concern about using these chemical indicators is that other sources including manures, fertilizers and waste waters from human or animal activities already exist in farming area. However, we lack the understanding of how groundwater contamination due to mass burial of carcass can be differentiated from the contamination due to livestock manures which shows similar chemical characteristics. The chemical compositions of the leachate from carcass burial site and the wastewater from livestock manure treatment facilities were compared. The chemical compositions considered include total organic carbon (TOC), total nitrogen (TN), nitrate, organic nitrogen (Organic nitrogen =TN-Ammonium Nitrogen- Nitrate nitrogen), ammonia, chloride, sodium, potassium and amino acids (20 analytes). The ratios of concentrations of the chemical compositions as indicators of contamination were determined to distinguish the sources of contamination in groundwater. Indicators which showed a linear relationship between two factors and revealed a distinct difference between the carcass leachate and livestock manure were chosen. In addition, the background level of the indicators in groundwater which was presumed not to be contaminated with the leachate was also considered. The indicators selected from these step were TN/nitrate nitrogen, organic nitrogen/TN, organic nitrogen/Cl and organic nitrogen/Na. In a similar manner, concentrations and peak pattern of amino acids with LC-MSMS as indicators were also selected. One more step added to identify the source of a contaminant release was the consideration of the transport of 20 amino acids in the subsurface which could significantly change the peak pattern among different amino acids. Six group of amino acid as indicators were chosen and they were Isoleucine/Valine, Leucine/Tryptophane, Valine/Tryptophane, Lysine/Leucine, Lysine/Isoleucine and Methionine/Lysine. The use of chemical indicators was attempted in this study to distinguish the sources of contamination by considering both the concentration of contaminants and the unique patterns of contamination.

  13. Arsenic Contamination in Groundwater of North Eastern India

    Microsoft Academic Search

    A. K. Singh

    Groundwater arsenic contamination and sufferings of people have been reported in 20 countries in different parts of the world. The magnitude is considered highest in five Asian countries and the severity is in order of Bangladesh>India>Mangolia>China>Taiwan. In all these countries, more and more groundwater withdrawal is taking place because of increase in agricultural irrigation. In India after West Bengal and

  14. Identification and Tracing Groundwater Contamination by Livestock Burial Sites

    NASA Astrophysics Data System (ADS)

    Ko, K.; Ha, K.; Park, S.; Kim, Y.; Lee, K.

    2011-12-01

    Foot-and-mouth disease (FMD) or hoof-and-mouth disease is a severe plague for animal farming that affects cloven-hoofed animals such as cattle, pigs, sheep, and goats. Since it is highly infectious and can be easily proliferated by infected animals, contaminated equipments, vehicles, clothing, people, and predators. It is widely known that the virus responsible for FMD is a picornavirus, the prototypic member of the genus Aphthovirus. A serious outbreak of foot-and-mouth disease, leading to the stamping out of 3.53 millions of pigs and cattle and the construction of 4,538 burial sites until 15th March, 2011. The build-up of carcass burial should inevitably produce leachate by the decomposition of buried livestock affecting the surround environment such as air, soil, groundwater, and surface water. The most important issues which are currently raised by scientists are groundwater contamination by leachate from the livestock burial sites. This study examined the current status of FMD outbreak occurred in 2010-2011 and the issues of groundwater contamination by leachate from livestock burial sites. The hydrogeochemical, geophysical, and hydrogeological studies were executed to identify and trace groundwater contamination by leachate from livestock burial sites. Generally livestock mortality leachate contains high concentrations of NH3-N, HCO3-, Cl-, SO42-, K+, Na+, P along with relative lesser amounts of iron, calcium, and magnesium. The groundwater chemical data around four burial sites showed high NH3-N, HCO3-, and K+ suggesting the leachate leakage from burial sites. This is also proved by resistivity monitoring survey and tracer tests. The simulation results of leachate dispersion showed the persistent detrimental impacts for groundwater environment for a long time (~50 years). It is need to remove the leachate of burial sites to prevent the dispersion of leachate from livestock burial to groundwater and to monitor the groundwater quality. The most important forthcoming issues for livestock burial are the treatment of leachate, protection of groundwater contamination by leachate, prevention of land slide, and prevention of rainfall percolation into burial site. It is also needed to develop the remediation, prospecting, and management technologies of groundwater contamination by carcass burial.

  15. Assessment of ground-water contamination in the alluvial aquifer near West Point, Kentucky

    USGS Publications Warehouse

    Lyverse, M.A.; Unthank, M.D.

    1988-01-01

    Well inventories, water level measurements, groundwater quality samples, surface geophysical techniques (specifically, electromagnetic techniques), and test drilling were used to investigate the extent and sources of groundwater contamination in the alluvial aquifer near West Point, Kentucky. This aquifer serves as the principal source of drinking water for over 50,000 people. Groundwater flow in the alluvial aquifer is generally unconfined and moves in a northerly direction toward the Ohio River. Two large public supply well fields and numerous domestic wells are located in this natural flow path. High concentrations of chloride in groundwater have resulted in the abandonment of several public supply wells in the West Point areas. Chloride concentrations in water samples collected for this study were as high as 11,000 mg/L. Electromagnetic techniques indicated and test drilling later confirmed that the source of chloride in well waters was probably improperly plugged or unplugged, abandoned oil and gas exploration wells. The potential for chloride contamination of wells exists in the study area and is related to proximity to improperly abandoned oil and gas exploration wells and to gradients established by drawdowns associated with pumped wells. Periodic use of surface geophysical methods, in combination with added observation wells , could be used to monitor significant changes in groundwater quality related to chloride contamination. (USGS)

  16. 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.

  17. Quantifying Groundwater and Contaminant Flux in Fractured Rock Systems

    NASA Astrophysics Data System (ADS)

    Cho, J.; Newman, M. A.; Klammler, H.; Hatfield, K.; Annable, M. D.; Parker, B. L.; Cherry, J.; Kroeker, R.; Pedler, W. H.

    2011-12-01

    Complex hydrogeologic conditions such as fractured and karst bedrock settings pose substantial economic and technical challenges both to the characterization and remediation of DNAPL source zones. The objective of this project is to demonstrate and validate the fractured rock passive flux meter (FRPFM) as new technology for measuring the magnitudes and directions of cumulative water and contaminant fluxes in fractured rock aquifers. The sensor consists of an inflatable core that compresses a reactive fabric against the wall of a borehole and to any water-filled fractures intersected by a borehole. The reactive fabric is designed to intercept and retain target groundwater contaminants (e.g. TCE, DCE, VC); in addition, the fabric releases non-toxic tracers, some of which visibly indicate active fracture location, aperture, orientation, and direction of fracture flow along a borehole, while others quantify cumulative groundwater discharge within the fractures. Field demonstration tests are ongoing at a site in Guelph, Ontario and at the Naval Air Warfare Center (NAWC) in West Trenton, NJ. The tests are comparing multiple technologies including fractured rock passive flux meters, hydrophysical logging, temperature logging, and borehole dilution tests. The technologies are being evaluated based upon their ability to: identify flowing fractures, determine flow direction, and quantify both water and contaminant mass flux in flowing fractures. Laboratory tests comparing the capabilities of each technology were previously performed in two separate flow simulators representing a range of likely field conditions: a planar single fracture simulator (fracture aperture = 0.5 mm; specific discharge range 25 - 2500 cm/day) and a large-scale three-dimensional aquifer box with layered high contrast flow zones simulating fractured zones (physical flow domain 2 m length, 0.5 m width, and 1 m height; specific discharge range 25 to 4000 cm/day (per layer)). Based upon initial field and laboratory tests sampling procedures have been developed for multiple scenarios depending upon the composition of fractured media and orientation of fractures encountered. These conditions have been found to be both site and sub-site specific depending upon multiple factors such as geology (rock composition) and the amount of weathering. At the Guelph site observed conditions have included discrete fractures, fractured zones exhibiting bulk conductivity, and washout zones more similar to karst dissolution channels. In each case the visual indications of flow intercepting the FRPFM are distinctive and unique, which allows for condition specific sampling of the sorbent for resident tracers and target contaminants.

  18. A case study simulation of DBCP groundwater contamination in Fresno County, California 2. Transport in the saturated subsurface

    Microsoft Academic Search

    Keith Loague; Robert H. Abrams; Stanley N. Davis; Anh Nguyen; Iris T. Stewart

    1998-01-01

    This paper is the second installment of a multipaper series concerned with simulating regional-scale groundwater contamination in Fresno County, CA as the result of long-term nonpoint source applications of 1,2-dibromo-3-chloropropane (DBCP). In the first part of this study [Loague, K., Lloyd, D., Nguyen, A., Davis, S.N., Abrams, R.H., 1997. A case study simulation of DBCP groundwater contamination in Fresno County,

  19. Catalytic destruction of groundwater contaminants in reactive extraction wells

    DOEpatents

    McNab, Jr., Walt W. (Concord, CA); Reinhard, Martin (Stanford, CA)

    2002-01-01

    A system for remediating groundwater contaminated with halogenated solvents, certain metals and other inorganic species based on catalytic reduction reactions within reactive well bores. The groundwater treatment uses dissolved hydrogen as a reducing agent in the presence of a metal catalyst, such a palladium, to reduce halogenated solvents (as well as other substituted organic compounds) to harmless species (e.g., ethane or methane) and immobilize certain metals to low valence states. The reactive wells function by removing water from a contaminated water-bearing zone, treating contaminants with a well bore using catalytic reduction, and then reinjecting the treated effluent into an adjacent water-bearing zone. This system offers the advantages of a compact design with a minimal surface footprint (surface facilities) and the destruction of a broad suite of contaminants without generating secondary waste streams.

  20. Vulnerability of deep groundwater in the Bengal Aquifer System to contamination by arsenic

    USGS Publications Warehouse

    Burgess, W.G.; Hoque, M.A.; Michael, H.A.; Voss, C.I.; Breit, G.N.; Ahmed, K.M.

    2010-01-01

    Shallow groundwater, the primary water source in the Bengal Basin, contains up to 100 times the World Health Organization (WHO) drinking-water guideline of 10g l 1 arsenic (As), threatening the health of 70 million people. Groundwater from a depth greater than 150m, which almost uniformly meets the WHO guideline, has become the preferred alternative source. The vulnerability of deep wells to contamination by As is governed by the geometry of induced groundwater flow paths and the geochemical conditions encountered between the shallow and deep regions of the aquifer. Stratification of flow separates deep groundwater from shallow sources of As in some areas. Oxidized sediments also protect deep groundwater through the ability of ferric oxyhydroxides to adsorb As. Basin-scale groundwater flow modelling suggests that, over large regions, deep hand-pumped wells for domestic supply may be secure against As invasion for hundreds of years. By contrast, widespread deep irrigation pumping might effectively eliminate deep groundwater as an As-free resource within decades. Finer-scale models, incorporating spatial heterogeneity, are needed to investigate the security of deep municipal abstraction at specific urban locations. ?? 2010 Macmillan Publishers Limited. All rights reserved.

  1. Large scale modelling of groundwater contamination from nitrate leaching

    NASA Astrophysics Data System (ADS)

    Refsgaard, J. C.; Thorsen, M.; Jensen, J. B.; Kleeschulte, S.; Hansen, S.

    1999-08-01

    Groundwater pollution from non-point sources, such as nitrate from agricultural activities, is a problem of increasing concern. Comprehensive modelling tools of the physically based type are well proven for small-scale applications with good data availability, such as plots or small experimental catchments. The two key problems related to large-scale simulation are data availability at the large scale and model upscaling/aggregation to represent conditions at larger scale. This paper presents a methodology and two case studies for large-scale simulation of aquifer contamination due to nitrate leaching. Readily available data from standard European level databases such as GISCO, EUROSTAT and the European Environment Agency (EEA) have been used as the basis of modelling. These data were supplemented by selected readily available data from national sources. The model parameters were all assessed from these data by use of various transfer functions, and no model calibration was carried out. The adopted upscaling procedure combines upscaling from point to field scale using effective parameters with a statistically based aggregation procedure from field to catchment scale, preserving the areal distribution of soil types, vegetation types and agricultural practices on a catchment basis. The methodology was tested on two Danish catchments with good simulation results on water balance and nitrate concentration distributions in groundwater. The upscaling/aggregation procedure appears to be applicable in many areas with regard to root zone processes such as runoff generation and nitrate leaching, while it has important limitations with regard to hydrograph shape due to its lack of accounting for scale effects in relation to stream aquifer interaction.

  2. Physical and numerical modeling results for controlling groundwater contaminants following shutdown of underground coal gasification processes

    SciTech Connect

    Boysen, J.E.; Mones, C.G.; Glaser, R.R.; Sullivan, S.

    1987-03-01

    Groundwater contamination has resulted from some of in-situ gasification field tests, and concern over groundwater contamination may hamper commercialization. When UCG recovery operations are terminated, energy remains stored as heat in the adjacent masses of rock and coal ash, and this energy is transferred into the coal seam. Coal continues to pyrolyze as a result of the transferred energy; the products of this coal pyrolysis are a source of groundwater contamination resulting from UCG. A laboratory simulator was developed, and six simulations of UCG postburn coal pyrolysis have been completed. The simulations show that the products of coal pyrolysis are the source of most contaminants associated with UCG operations. Injection of water directly into the UCG cavity can limit postburn coal pyrolysis and reduce the production of contaminants by cooling the masses of rubble and coal ash in the cavity. Water flow through the coal towards the cavity also limits postburn pyrolysis and subsequent contaminant generation; however, steam produced in the heated portions of the coal limits the rate of water flow. Simulation results indicate that UCG field tests should be operated so that the flow of pyrolysis liquids and gases into the formation is prevented and that the natural influx of water into the cavity is allowed. This can be accomplished by minimizing gas leakage to the formation during gasification, venting the cavity after the gasification process is complete, and maintaining low postburn cavity pressures. 11 refs., 17 figs., 17 tabs.

  3. OASIS: A GRAPHICAL DECISION SUPPORT SYSTEM FOR GROUNDWATER CONTAMINANT MODELING

    EPA Science Inventory

    Three new software technologies were applied to develop an efficient and easy to use decision support system far ground-water contaminant modeling. raphical interfaces create a more intuitive and effective form of communication with the computer compared to text-based interfaces....

  4. Persistent and emerging micro-organic contaminants in Chalk groundwater of England and France.

    PubMed

    Lapworth, D J; Baran, N; Stuart, M E; Manamsa, K; Talbot, J

    2015-08-01

    The Chalk aquifer of Northern Europe is an internationally important source of drinking water and sustains baseflow for surface water ecosystems. The areal distribution of microorganic (MO) contaminants, particularly non-regulated emerging MOs, in this aquifer is poorly understood. This study presents results from a reconnaissance survey of MOs in Chalk groundwater, including pharmaceuticals, personal care products and pesticides and their transformation products, conducted across the major Chalk aquifers of England and France. Data from a total of 345 sites collected during 2011 were included in this study to provide a representative baseline assessment of MO occurrence in groundwater. A suite of 42 MOs were analysed for at each site including industrial compounds (n=16), pesticides (n=14) and pharmaceuticals, personal care and lifestyle products (n=12). Occurrence data is evaluated in relation to land use, aquifer exposure, well depth and depth to groundwater to provide an understanding of vulnerable groundwater settings. PMID:25882715

  5. Natural biodegradation of organic contaminants in groundwater

    Microsoft Academic Search

    W W McNab; D W Rice

    1998-01-01

    There has recently been a growing awareness that natural processes are degrading contaminants of concern, and that the contribution these natural processes make to achieving cleanup goals needs to be formally considered during site-specific cleanup. Historical case data from a large number of releases has been used to evaluate the expectation for natural attenuation to contribute to the cleanup of

  6. Passive treatment of wastewater and contaminated groundwater

    DOEpatents

    Phifer, Mark A.; Sappington, Frank C.; Millings, Margaret R.; Turick, Charles E.; McKinsey, Pamela C.

    2006-12-12

    A bioremediation system using inorganic oxide-reducing microbial consortia for the treatment of, inter alia coal mine and coal yard runoff uses a containment vessel for contaminated water and a second, floating phase for nutrients. Biodegradable oils are preferred nutrients.

  7. Passive treatment of wastewater and contaminated groundwater

    DOEpatents

    Phifer, Mark A. (N. Augusta, SC); Sappington, Frank C. (Dahlonega, GA); Millings, Margaret R. (N. Augusta, SC); Turick, Charles E. (Aiken, SC); McKinsey, Pamela C. (Aiken, SC)

    2007-11-06

    A bioremediation system using inorganic oxide-reducing microbial consortia for the treatment of, inter alia coal mine and coal yard runoff uses a containment vessel for contaminated water and a second, floating phase for nutrients. Biodegradable oils are preferred nutrients.

  8. A pilot plant to treat chromium-contaminated groundwater

    SciTech Connect

    El-Shoubary, Y.; Speizer, N.; Seth, S.; Savoia, H. [Merck Mfg. Div., Somerset, NJ (United States)

    1998-12-31

    The groundwater at a site in California is contaminated with hexavalent chromium. Different treatment options were tested. The options tested included: carbon adsorption, ion exchange, chemical treatment, reverse osmosis, and in-place fixation. Electrochemical treatment was the treatment of choice. Treatment operations were designed with turn down flexibility to allow operation at variable flow rates. Metal reduction is the first treatment step after collection of the groundwater and lowering of the pH to 3 in an on-line acid tank. Soluble ferrous ions are produced in an off-line electrochemical cell using sacrificial electrodes.

  9. Acid mine drainage contaminates groundwater of a Tennessee watershed

    NASA Astrophysics Data System (ADS)

    O'Bara, Christopher J.; Don Estes, R.

    1985-09-01

    Water samples were collected from 18 natural springs within the West Fork of the Obey River watershed. Overton County, Tennessee, to determine if groundwater was adversely affected by runoff from abandoned surface coal mines Six springs were found to be affected severely and deemed unfit as a source of potable water Water quality of the remaining springs was essentially unaffected it appeared that proximity to surface mines, elevation at the outflow, and geology of the surrounding strata determined the quality of the groundwater

  10. Groundwater contamination studies - The state-of-the-art

    SciTech Connect

    Khondaker, A.N.; Al-Layla, R.I.; Hussain, T. (Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia))

    1990-01-01

    A systematic study was made of the available theoretical and experimental works. The study of groundwater flow and contaminant transport requires knowledge of many of the basic principles of geology, physics, chemistry, and mathematics; there is a close kinship between groundwater hydrology, soil physics, soil mechanics, rock mechanics, and petroleum engineering. These interdisciplinary studies can be broadly categorized as theory and development of solute-transport phenomena, modeling of solute transport, and studies on model parameters. There are a number of important areas which need further research to predict the fate and the behavior of contaminants in the subsurface system, including: (1) additional work to derive field-scale models; (2) correlation between field and laboratory values of input parameters for solute transport models; (3) continued investigation of the geochemistry of contaminant reactions in both saturated and unsaturated subsurface environments; (4) further study of the chemical and biological reaction on the permeability of aquifer materials; (5) systematic comparison of all existing models and the advanced solution techniques; (6) development of an efficient model including all the biological processes; (7) better understanding of reaction rates in the subsurface environment. The necessity of interdisciplinary cooperation among investigators is essential for the future advancements in the ability to deal with groundwater contamination problems.

  11. Lead Groundwater Contamination of Groundwater in the Northeast of Buenos Aires Province, Argentina.

    E-print Network

    Santos, Juan

    of characteristics combined with a mixed finite element procedure to simulate the plume evolution in time. #12;The by atmospheric deposition, and solid and liquid waste disposal. Groundwater receives lead contamination from. (1995) has presented a coupled transport-chemistry hydrogeochemical model, which can predict

  12. Nebraska's groundwater legacy: Nitrate contamination beneath irrigated cropland

    PubMed Central

    Exner, Mary E; Hirsh, Aaron J; Spalding, Roy F

    2014-01-01

    A 31 year record of ?44,000 nitrate analyses in ?11,500 irrigation wells was utilized to depict the decadal expansion of groundwater nitrate contamination (N???10 mg/L) in the irrigated corn-growing areas of eastern and central Nebraska and analyze long-term nitrate concentration trends in 17 management areas (MAs) subject to N fertilizer and budgeting requirements. The 1.3 M contaminated hectares were characterized by irrigation method, soil drainage, and vadose zone thickness and lithology. The areal extent and growth of contaminated groundwater in two predominately sprinkler-irrigated areas was only ?20% smaller beneath well-drained silt loams with thick clayey-silt unsaturated layers and unsaturated thicknesses >15 m (400,000 ha and 15,000 ha/yr) than beneath well and excessively well-drained soils with very sandy vadose zones (511,000 ha and 18,600 ha/yr). Much slower expansion (3700 ha/yr) occurred in the 220,000 contaminated hectares in the central Platte valley characterized by predominately gravity irrigation on thick, well-drained silt loams above a thin (?5.3 m), sandy unsaturated zone. The only reversals in long-term concentration trends occurred in two MAs (120,500 ha) within this contaminated area. Concentrations declined 0.14 and 0.20 mg N/L/yr (p?20 years of management. Average annual concentrations in 10 MAs are increasing (p?groundwater concentrations have not yet reached steady state. While management practices likely have slowed increases in groundwater nitrate concentrations, irrigation and nutrient applications must be more effectively controlled to retain nitrate in the root zone. PMID:25558112

  13. Groundwater Pollution Source Identification using Linked ANN-Optimization Model

    NASA Astrophysics Data System (ADS)

    Ayaz, Md; Srivastava, Rajesh; Jain, Ashu

    2014-05-01

    Groundwater is the principal source of drinking water in several parts of the world. Contamination of groundwater has become a serious health and environmental problem today. Human activities including industrial and agricultural activities are generally responsible for this contamination. Identification of groundwater pollution source is a major step in groundwater pollution remediation. Complete knowledge of pollution source in terms of its source characteristics is essential to adopt an effective remediation strategy. Groundwater pollution source is said to be identified completely when the source characteristics - location, strength and release period - are known. Identification of unknown groundwater pollution source is an ill-posed inverse problem. It becomes more difficult for real field conditions, when the lag time between the first reading at observation well and the time at which the source becomes active is not known. We developed a linked ANN-Optimization model for complete identification of an unknown groundwater pollution source. The model comprises two parts- an optimization model and an ANN model. Decision variables of linked ANN-Optimization model contain source location and release period of pollution source. An objective function is formulated using the spatial and temporal data of observed and simulated concentrations, and then minimized to identify the pollution source parameters. In the formulation of the objective function, we require the lag time which is not known. An ANN model with one hidden layer is trained using Levenberg-Marquardt algorithm to find the lag time. Different combinations of source locations and release periods are used as inputs and lag time is obtained as the output. Performance of the proposed model is evaluated for two and three dimensional case with error-free and erroneous data. Erroneous data was generated by adding uniformly distributed random error (error level 0-10%) to the analytically computed concentration values. The main advantage of the proposed model is that it requires only upper half of the breakthrough curve and is capable of predicting source parameters when the lag time is not known. Linking of ANN model with proposed optimization model reduces the dimensionality of the decision variables of the optimization model by one and hence complexity of optimization model is reduced. The results show that our proposed linked ANN-Optimization model is able to predict the source parameters for the error-free data accurately. The proposed model was run several times to obtain the mean, standard deviation and interval estimate of the predicted parameters for observations with random measurement errors. It was observed that mean values as predicted by the model were quite close to the exact values. An increasing trend was observed in the standard deviation of the predicted values with increasing level of measurement error. The model appears to be robust and may be efficiently utilized to solve the inverse pollution source identification problem.

  14. Monitoring ecological recovery in a stream impacted by contaminated groundwater

    SciTech Connect

    Southworth, G.R.; Cada, G.F.; Kszos, L.A.; Peterson, M.J.; Smith, J.G. [and others

    1997-11-01

    Past in-ground disposal practices in Bear Creek Valley resulted in contamination of Bear Creek and consequent ecological damage. A biological monitoring program initiated in 1984 has evaluated the effectiveness of the extensive remedial actions undertaken to address contamination sources. Elements of the monitoring program included toxicity testing with fish and invertebrates, bioaccumulation monitoring, and instream monitoring of streambed invertebrate and fish communities. In the mid 1980`s, toxicity tests on stream water indicated that the headwaters of the stream were acutely toxic to fish and aquatic invertebrates as a result of infiltration of a metal-enriched groundwater from ponds used to dispose of acid wastes. Over a twelve year period, measurable toxicity in the headwaters decreased, first becoming non-toxic to larval fish but still toxic to invertebrates, then becoming intermittently toxic to invertebrates. By 1997, episodic toxicity was infrequent at the site that was acutely toxic at the start of the study. Recovery in the fish community followed the pattern of the toxicity tests. Initially, resident fish populations were absent from reaches where toxicity was measured, but as toxicity to fish larvae disappeared, the sites in upper Bear Creek were colonized by fish. The Tennessee dace, an uncommon species receiving special protection by the State of Tennessee, became a numerically important part of the fish population throughout the upper half of the creek, making Bear Creek one of the most significant habitats for this species in the region. Although by 1990 fish populations were comparable to those of similar size reference streams, episodic toxicity in the headwaters coincided with a recruitment failure in 1996. Bioaccumulation monitoring indicated the presence of PCBs and mercury in predatory fish in Bear Creek, and whole forage fish contained elevated levels of cadmium, lead, lithium, nickel, mercury, and uranium.

  15. Groundwater arsenic contamination in Bangladesh-21 Years of research.

    PubMed

    Chakraborti, Dipankar; Rahman, Mohammad Mahmudur; Mukherjee, Amitava; Alauddin, Mohammad; Hassan, Manzurul; Dutta, Rathindra Nath; Pati, Shymapada; Mukherjee, Subhash Chandra; Roy, Shibtosh; Quamruzzman, Quazi; Rahman, Mahmuder; Morshed, Salim; Islam, Tanzima; Sorif, Shaharir; Selim, Md; Islam, Md Razaul; Hossain, Md Monower

    2015-07-01

    Department of Public Health Engineering (DPHE), Bangladesh first identified their groundwater arsenic contamination in 1993. But before the international arsenic conference in Dhaka in February 1998, the problem was not widely accepted. Even in the international arsenic conference in West-Bengal, India in February, 1995, representatives of international agencies in Bangladesh and Bangladesh government attended the conference but they denied the groundwater arsenic contamination in Bangladesh. School of Environmental Studies (SOES), Jadavpur University, Kolkata, India first identified arsenic patient in Bangladesh in 1992 and informed WHO, UNICEF of Bangladesh and Govt. of Bangladesh from April 1994 to August 1995. British Geological Survey (BGS) dug hand tube-wells in Bangladesh in 1980s and early 1990s but they did not test the water for arsenic. Again BGS came back to Bangladesh in 1992 to assess the quality of the water of the tube-wells they installed but they still did not test for arsenic when groundwater arsenic contamination and its health effects in West Bengal in Bengal delta was already published in WHO Bulletin in 1988. From December 1996, SOES in collaboration with Dhaka Community Hospital (DCH), Bangladesh started analyzing hand tube-wells for arsenic from all 64 districts in four geomorphologic regions of Bangladesh. So far over 54,000 tube-well water samples had been analyzed by flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS). From SOES water analysis data at present we could assess status of arsenic groundwater contamination in four geo-morphological regions of Bangladesh and location of possible arsenic safe groundwater. SOES and DCH also made some preliminary work with their medical team to identify patients suffering from arsenic related diseases. SOES further analyzed few thousands biological samples (hair, nail, urine and skin scales) and foodstuffs for arsenic to know arsenic body burden and people sub-clinically affected. SOES and DCH made a few follow-up studies in some districts to know their overall situations after 9 to 18 years of their first exposure. The overall conclusion from these follow-up studies is (a) villagers are now more aware about the danger of drinking arsenic contaminated water (b) villagers are currently drinking less arsenic contaminated water (c) many villagers in affected village died of cancer (d) arsenic contaminated water is in use for agricultural irrigation and arsenic exposure from food chain could be future danger. Since at present more information is coming about health effects from low arsenic exposure, Bangladesh Government should immediately focus on their huge surface water management and reduce their permissible limit of arsenic in drinking water. PMID:25660323

  16. Contamination of groundwater under cultivated fields in an arid environment, central Arava Valley, Israel

    USGS Publications Warehouse

    Oren, O.; Yechieli, Y.; Böhlke, J.K.; Dody, A.

    2004-01-01

    The purpose of this study is to obtain a better understanding of groundwater contamination processes in an arid environment (precipitation of 50 mm/year) due to cultivation. Additional aims were to study the fate of N, K, and other ions along the whole hydrological system including the soil and vadose zone, and to compare groundwater in its natural state with contaminated groundwater (through the drilling of several wells). A combination of physical, chemical, and isotopic analyses was used to describe the hydrogeological system and the recharge trends of water and salts to the aquifers. The results indicate that intensive irrigation and fertilization substantially affected the quantity and quality of groundwater recharge. Low irrigation efficiency of about 50% contributes approximately 3.5-4 millionm3/year to the hydrological system, which corresponds to 0.65 m per year of recharge in the irrigated area, by far the most significant recharge mechanism. Two main contamination processes were identified, both linked to human activity: (1) salinization due to circulation of dissolved salts in the irrigation water itself, mainly chloride, sulfate, sodium and calcium, and (2) direct input of nitrate and potassium mainly from fertilizers. The nitrate concentrations in a local shallow groundwater lens range between 100 and 300 mg/l and in the upper sub-aquifer are over 50 mg/l. A major source of nitrate is fertilizer N in the excess irrigation water. The isotopic compositions of ??15N- NO3 (range of 4.9-14.8???) imply also possible contributions from nearby sewage ponds and/or manure. Other evidence of contamination of the local groundwater lens includes high concentrations of K (20-120 mg/l) and total organic carbon (about 10 mg/l). ?? 2004 Elsevier B.V. All rights reserved.

  17. Evaluation of sustained release polylactate electron donors for removal of hexavalent chromium from contaminated groundwater

    E-print Network

    Brodie, E.L.

    2012-01-01

    www.regenesis.com/contaminated-site-remediation-products/chlorinated solvent contaminated sites, (Koenigsberg, 2001)contaminated groundwater by in-situ cometabolic reduction. Sixth Annual In-Situ and On-Site

  18. Hydraulic Containment of TCE Contaminated Groundwater at the DOE Portsmouth Gaseous Diffusion Plant

    SciTech Connect

    Lewis, A.C.; Rieske, D.P.G.; Baird, D.R.P.E. [CDM, Piketon, OH (United States)

    2008-07-01

    This paper will describe the progress of a groundwater remedial action at the Portsmouth Gaseous Diffusion Plant (PORTS), a Department of Energy (DOE) facility that enriched uranium from the early 1950's until 2000. The X-749 southern boundary hydraulic containment system, combining a four-well extraction system with a previously constructed subsurface barrier wall, has been employed at PORTS. The hydraulic containment project has been implemented as part of containment and remediation of the X-749/X-120 area trichloroethylene (TCE) contaminant. The X-749/X-120 groundwater contaminant plume is located in the south central section (Quadrant I) of the PORTS facility. The plume is associated with the former X-120 Goodyear Training Facility and a landfill known as the X-749 Contaminated Materials Disposal Facility. The principal contaminants of concern are chlorinated solvents (primarily TCE) and technetium-99 (Tc-99). A subsurface barrier wall (X-749 South Barrier Wall) was completed in 1994 at the PORTS southern reservation boundary as an interim remedial measure to slow the advancement of the leading edge of the contaminated groundwater plume or to prevent the plume from migrating off DOE property. Remedial measures identified by Ohio Environmental Protection Agency (Ohio EPA) included installation of a barrier wall around the eastern and southern portions of the X-749 landfill to provide source control and installation of a phyto-remediation system to help contain groundwater flow and remove volatile organic compounds. Previous remedial measures that were implemented as elements of 'closures' on the X-749 landfill included a multimedia cap, barrier walls, and a groundwater collection system. Despite these measures, the X-749/X-120 groundwater plume has migrated beyond the southern DOE property boundary. Current TCE concentrations in off-site groundwater monitoring wells are below the preliminary remediation goal and drinking water maximum contaminant level for TCE of 5 {mu}g/kg, but continue to increase. Hydraulic containment was selected as the method for controlling the plume at the southern DOE property boundary. Recent borings and pumping tests indicate that approximately a 400-foot section of the existing subsurface barrier wall near the DOE property boundary may been improperly keyed into the Sunbury Shale bedrock which underlies the unconsolidated uppermost Gallia sand and gravel aquifer (Gallia). This gap is reported to be as much as 4 vertical feet. In addition, the X-749 groundwater plume is migrating around the western end of the X-749 South Barrier Wall. Four groundwater extraction wells were installed at the DOE property boundary to provide hydraulic control of the plume currently flowing under and around the existing subsurface barrier wall. Placement of the new extraction wells was based on groundwater modeling and data collected from pumping tests in the area. The extracted groundwater is being sent to the on-site X-622 Groundwater Treatment Facility via subsurface piping. The hydraulic containment system began operation in June 2007. The preliminary water elevations from monitoring wells in the vicinity of two of the four extraction wells demonstrate a significant decrease in groundwater potentiometric head in the southern boundary area. The current extraction rates should be adequate to contain the leading edge of the contaminant plume. Monitoring wells in the area will continue to be sampled on a quarterly basis. (authors)

  19. Groundwater contaminations and health perspectives in developing world case study: Gaza Strip

    Microsoft Academic Search

    B. Shomar

    2011-01-01

    Groundwater is the only source of water in the Gaza Strip. The results of a 10-year monitoring program revealed that more\\u000a than 90% of the available water is not suitable for drinking purposes as a result of elevated chemical contaminants as well\\u000a as microbiological organisms. The archives of the local hospitals showed catastrophic records on diseases caused by water\\u000a directly

  20. Y-12 Groundwater Protection Program Extent Of The Primary Groundwater Contaminants At The Y-12 National Security Complex

    SciTech Connect

    none,

    2013-12-01

    This report presents data summary tables and maps used to define and illustrate the approximate lateral extent of groundwater contamination at the U.S. Department of Energy (DOE) Y-12 National Security Complex (Y-12) in Oak Ridge, Tennessee. The data tables and maps address the primary (i.e., most widespread and mobile) organic, inorganic, and radiological contaminants in the groundwater. The sampling locations, calculated contaminant concentrations, plume boundary values, and paired map format used to define, quantify, delineate, and illustrate the approximate extent of the primary organic, inorganic, and radiological contaminants in groundwater at Y-12 are described.

  1. Logistic regression modeling to assess groundwater vulnerability to contamination in Hawaii, USA.

    PubMed

    Mair, Alan; El-Kadi, Aly I

    2013-10-01

    Capture zone analysis combined with a subjective susceptibility index is currently used in Hawaii to assess vulnerability to contamination of drinking water sources derived from groundwater. In this study, we developed an alternative objective approach that combines well capture zones with multiple-variable logistic regression (LR) modeling and applied it to the highly-utilized Pearl Harbor and Honolulu aquifers on the island of Oahu, Hawaii. Input for the LR models utilized explanatory variables based on hydrogeology, land use, and well geometry/location. A suite of 11 target contaminants detected in the region, including elevated nitrate (>1 mg/L), four chlorinated solvents, four agricultural fumigants, and two pesticides, was used to develop the models. We then tested the ability of the new approach to accurately separate groups of wells with low and high vulnerability, and the suitability of nitrate as an indicator of other types of contamination. Our results produced contaminant-specific LR models that accurately identified groups of wells with the lowest/highest reported detections and the lowest/highest nitrate concentrations. Current and former agricultural land uses were identified as significant explanatory variables for eight of the 11 target contaminants, while elevated nitrate was a significant variable for five contaminants. The utility of the combined approach is contingent on the availability of hydrologic and chemical monitoring data for calibrating groundwater and LR models. Application of the approach using a reference site with sufficient data could help identify key variables in areas with similar hydrogeology and land use but limited data. In addition, elevated nitrate may also be a suitable indicator of groundwater contamination in areas with limited data. The objective LR modeling approach developed in this study is flexible enough to address a wide range of contaminants and represents a suitable addition to the current subjective approach. PMID:23948235

  2. Spatial control of groundwater contamination, using principal component analysis

    NASA Astrophysics Data System (ADS)

    Rao, N. Subba

    2014-06-01

    A study on the geochemistry of groundwater was carried out in a river basin of Andhra Pradesh to probe into the spatial controlling processes of groundwater contamination, using principal component analysis (PCA). The PCA transforms the chemical variables, pH, EC, Ca2+, Mg2+, Na+, K+, HCO, Cl-, SO, NO and F-, into two orthogonal principal components (PC1 and PC2), accounting for 75% of the total variance of the data matrix. PC1 has high positive loadings of EC, Na+, Cl-, SO, Mg2+ and Ca2+, representing a salinity controlled process of geogenic (mineral dissolution, ion exchange, and evaporation), anthropogenic (agricultural activities and domestic wastewaters), and marine (marine clay) origin. The PC2 loadings are highly positive for HCO , F-, pH and NO, attributing to the alkalinity and pollution controlled processes of geogenic and anthropogenic origins. The PC scores reflect the change of groundwater quality of geogenic origin from upstream to downstream area with an increase in concentration of chemical variables, which is due to anthropogenic and marine origins with varying topography, soil type, depth of water levels, and water usage. Thus, the groundwater quality shows a variation of chemical facies from Na+ > Ca2+ > Mg2+ > K+: HCO > Cl- > SO NO > F-at high topography to Na+ > Mg2+ > Ca2+ > K+: Cl- > HCO > SO NO > F- at low topography. With PCA, an effective tool for the spatial controlling processes of groundwater contamination, a subset of explored wells is indexed for continuous monitoring to optimize the expensive effort.

  3. Statistical modeling of global geogenic arsenic contamination in groundwater.

    PubMed

    Amini, Manouchehr; Abbaspour, Karim C; Berg, Michael; Winkel, Lenny; Hug, Stephan J; Hoehn, Eduard; Yang, Hong; Johnson, C Annette

    2008-05-15

    Contamination of groundwaters with geogenic arsenic poses a major health risk to millions of people. Although the main geochemical mechanisms of arsenic mobilization are well understood, the worldwide scale of affected regions is still unknown. In this study we used a large database of measured arsenic concentration in groundwaters (around 20,000 data points) from around the world as well as digital maps of physical characteristics such as soil, geology, climate, and elevation to model probability maps of global arsenic contamination. A novel rule-based statistical procedure was used to combine the physical data and expert knowledge to delineate two process regions for arsenic mobilization: "reducing" and "high-pH/ oxidizing". Arsenic concentrations were modeled in each region using regression analysis and adaptive neuro-fuzzy inferencing followed by Latin hypercube sampling for uncertainty propagation to produce probability maps. The derived global arsenic models could benefit from more accurate geologic information and aquifer chemical/physical information. Using some proxy surface information, however, the models explained 77% of arsenic variation in reducing regions and 68% of arsenic variation in high-pH/oxidizing regions. The probability maps based on the above models correspond well with the known contaminated regions around the world and delineate new untested areas that have a high probability of arsenic contamination. Notable among these regions are South East and North West of China in Asia, Central Australia, New Zealand, Northern Afghanistan, and Northern Mali and Zambia in Africa. PMID:18546706

  4. Assessment of groundwater pathways and contaminant transport in Florida and Georgia using multiple chemical and microbiological indicators

    USGS Publications Warehouse

    Mahon, Gary L.

    2011-01-01

    The hydrogeology of Florida, especially in the northern part of the state, and southwestern Georgia is characterized by a predominance of limestone aquifers overlain by varying amounts of sands, silts, and clays. This karstic system of aquifers and their associated springs is particularly vulnerable to contamination from various anthropogenic activities at the land surface. Numerous sinkholes, disappearing streams, and conduit systems or dissolution pathways, often associated with large spring systems, allow rapid movement of contaminants from the land surface to the groundwater system with little or no attenuation or degradation. The fate of contaminants in the groundwater system is not fully understood, but traveltimes from sources are greatly reduced when conduits are intercepted by pumping wells and springs. Contaminant introduction to groundwater systems in Florida and Georgia is not limited to seepage from land surface, but can be associated with passive (drainage wells) and forced subsurface injection (aquifer storage and recovery, waste-water disposal).

  5. Groundwater contamination from well points -- an experience from the Norwegian groundwater monitoring network.

    PubMed

    Jaeger, Øystein; Grimstvedt, Andreas; Frengstad, Bjørn; Reimann, Clemens

    2006-08-15

    Until 2005 the observation wells of the Norwegian Groundwater Monitoring Network in Quaternary aquifers were equipped with metal well points with brass lining. A laboratory leaching test using a new well point demonstrated that the well point material (galvanized iron pipe), the brass lining and the solder used to fix the lining could cause substantial contamination of the collected well water with a long list of chemical elements (Sn, Zn, Pb, Sb, Cd, Fe, Cu, Mn and Al), depending on well capacity, contact time water/well point and pH. Because groundwater chemistry is receiving increased attention in groundwater monitoring all wells were equipped with high density polyethylene (HDPE) points during the years 2004-2005. The HDPE points did not return any values above detection in a similar leaching test, with some minor values of Zn being the only exception. PMID:16580048

  6. Robust decision analysis for environmental management of groundwater contamination sites

    E-print Network

    Vesselinov, Velimir V; Katzman, Danny

    2013-01-01

    In contrast to many other engineering fields, the uncertainties in subsurface processes (e.g., fluid flow and contaminant transport in aquifers) and their parameters are notoriously difficult to observe, measure, and characterize. This causes severe uncertainties that need to be addressed in any decision analysis related to optimal management and remediation of groundwater contamination sites. Furthermore, decision analyses typically rely heavily on complex data analyses and/or model predictions, which are often poorly constrained as well. Recently, we have developed a model-driven decision-support framework (called MADS; http://mads.lanl.gov) for the management and remediation of subsurface contamination sites in which severe uncertainties and complex physics-based models are coupled to perform scientifically defensible decision analyses. The decision analyses are based on Information Gap Decision Theory (IGDT). We demonstrate the MADS capabilities by solving a decision problem related to optimal monitoring ...

  7. Groundwater chemistry in the nitrate contaminated area in Shimabara, Nagasaki Prefecture, Japan

    NASA Astrophysics Data System (ADS)

    Nakagawa, K.

    2014-12-01

    Groundwater contamination by nitrate from agricultural fields is a problem shared by many parts of the world. Shimabara, Nagasaki prefecture, Japan is an important agricultural district experiencing this problem. In Shimabara, drinking water relies on the groundwater. In this study, groundwater samples were collected at 40 locations such as residents and municipal waterworks wells, springs and rivers from August 2011 to November 2013. NO3-N concentration of 15 samples exceeded 10 mg L-1 (drinking water standard in Japan). Maximum NO3-N concentration was 26.6 mg L-1. Correlation coefficients were calculated between ion components of collected samples (n=277). NO3- had the highest positive correlation with Cl-(r =0.956) and had positive correlation with K+(r=0.679), SO42-(r=0.654) and Ca2+(r=0.593), respectively. The results revealed that Cl- and K+ related to livestock wastes, SO42- related to chemical fertilizers and Ca2+ related to calcareous materials. Main source of NO3- is from livestock wastes. To understand groundwater chemistry in detail, principal component analysis (PCA) and cluster analysis were carried out. Result from the PCA, chemical characteristics of groundwater was summarized by the first principal component and the second principal component. Both of two principal components reflected nitrate contamination and ion dissolution from aquifer matrix during groundwater flows. Result from the cluster analysis, chemical characteristics of groundwater was classified into four clusters. Nitrate polluted samples into specific cluster and the rest samples were classified into other clusters depending on the original water quality.

  8. Associations of free-living bacteria and dissolved organic compounds in a plume of contaminated groundwater

    USGS Publications Warehouse

    Harvey, R.W.; Barber, L.B., II

    1992-01-01

    Associations of free-living bacteria (FLB) and dissolved organic contaminants in a 4-km-long plume of sewage-contaminated groundwater were investigated. Abundance of FLB in the core of the plume (as delineated by maximum specific conductance) steadily decreased in the direction of flow from a point 0.25 km downgradient from the source to the toe of the plume. At 0.25 km downgradient, FLB comprised up to 31% of the total bacterial population, but constituted < 7% of the population at 2 km downgradient. Abundance of FLB correlated strongly (r = 0.80 n = 23) with total dissolved organic carbon (DOC) in contaminated groundwater between 0.64 and 2.1 km downgradient, although distributions of individual contaminants such as di-, tri- and tetrachloroethene were highly variable, and their association with FLB less clear. Numbers of FLB in the downgradient portion of the plume which is contaminated with branched-chain alkylbenzenesulfonate (ABS) surfactants were low (< 5??108/L) in spite of relatively high levels of DOC (up to 4 mg/L). However, abundance of FLB correlated strongly with non-surfactant DOC along vertical transects through the plume. The ratio of FLB to DOC and the ratio of FLB to attached bacteria generally decreased in the direction of flow and, consequently, with the age of the organic contaminants.

  9. Herbicide contamination of surficial groundwater in Northern Italy.

    PubMed

    Guzzella, Licia; Pozzoni, Fiorenzo; Giuliano, Giuseppe

    2006-07-01

    Data on herbicide pollution in groundwater are rather scarce; monitoring data are based on single investigation, focussing on limited area and on few compounds of interest. The large number of approved active ingredients (approximately 600 chemicals) makes difficult to obtain an accurate and actual information on herbicide application in different countries, even if herbicides are the second most important class of pesticides used in the European Union. The results of a two-year monitoring campaign undertaken in two areas intensively cultivated at Lombardy, Northern Italy, showed a diffuse groundwater contamination due to active ingredients and their metabolites. More than 50% of samples overcame M.A.C. and the most common herbicides were Atrazine, Terbuthylazine and Metolachlor, while DEA and DET metabolites were often characterized by greater concentrations than their relative active principles. PMID:16413952

  10. Influencing Factors and a Proposed Evaluation Methodology for Predicting Groundwater Contamination Potential from Stormwater Infiltration Activities

    E-print Network

    Clark, Shirley E.

    Contamination Potential from Stormwater Infiltration Activities Shirley E. Clark and Robert Pitt Abstract To offset the detrimental effects of urbanization on groundwater recharge, stormwater managers are focusing

  11. Anthropogenic groundwater contamination by selenium at Suchomasty Village (Prague Basin, Czech Republic)

    NASA Astrophysics Data System (ADS)

    Kadlecova, Renata; Bruthans, Jiri; Buzek, Frantisek; Dousova, Barbora; Konecna, Stanislava; Zeman, Ondrej

    2010-05-01

    The aim of the project is to clarify and characterize the probable sources of increased selenium contamination in groundwater at Suchomasty Village located 35 km SW of Prague. The village is supplied by drinking water from a 25 m deep bore-hole with catchment formed by Ordovician to Devonian mostly sedimentary rocks of the Prague Basin. The selenium concentrations have suddenly exceeded limit 10 ?g/l up to 123 ?g/l since 2007. Several possible selenium sources were predicted in the bore-hole catchment: (i) Paleozoic bedrock, (ii) ash from coal power stations used for arable soil improvement, (iii) selenium-accumulating plants used as manure and (iv) an old rubbish dump. Samples of bedrock, soil and anthropogenic deposits were collected for selenium concentration analyses from five excavated test-holes up to 2.5 m deep. Concentration of selenium was analyzed in month intervals in the water from the bore-hole and from a shallow well. Groundwater residence time was determined using tritium and SF6. Oxygen isotopic composition could help us to better understanding of groundwater dynamics. The AAS and ICP-OES analyses of bedrock and soils revealed no distinct increased selenium concentrations. Devonian limestone contains 5 mg/kg, field soil with ash up to 25 mg/kg and selenium-accumulating plants 6 mg/kg. The highest selenium concentration was found in material from the dump (up to 45 mg/kg) stored in abandoned quarry located 1 km away from the bore-hole. We assume the dump is a main potential source of selenium contamination. Although the average groundwater residence time is up to 20 years, the selenium contamination has reached the bore-hole in 18 month since dump reclamation. It is possible that the fast groundwater circulation has been using more karstified rock. Based on obtained data the selenium is hold in suspension transported by groundwater. Filtration of drinking water should help in a case of continuing long-term increase of selenium contamination. Project is supported by the Ministry of the Environment CR (SP/2e1/153/07).

  12. Numerical model for the uptake of groundwater contaminants by phreatophytes

    USGS Publications Warehouse

    Widdowson, M.A.; El-Sayed, A.; Landmeyer, J.E.

    2008-01-01

    Conventional solute transport models do not adequately account for the effects of phreatophytic plant systems on contaminant concentrations in shallow groundwater systems. A numerical model was developed and tested to simulate threedimensional reactive solute transport in a heterogeneous porous medium. Advective-dispersive transport is coupled to biodegradation, sorption, and plantbased attenuation processes including plant uptake and sorption by plant roots. The latter effects are a function of the physical-chemical properties of the individual solutes and plant species. Models for plant uptake were tested and evaluated using the experimental data collected at a field site comprised of hybrid poplar trees. A non-linear equilibrium isotherm model best represented site conditions.

  13. Simulation of nonpoint source contamination based on adaptive mesh refinement

    NASA Astrophysics Data System (ADS)

    Kourakos, G.; Harter, T.

    2014-12-01

    Contamination of groundwater aquifers from nonpoint sources is a worldwide problem. Typical agricultural groundwater basins receive contamination from a large array (in the order of ~10^5-6) of spatially and temporally heterogeneous sources such as fields, crops, dairies etc, while the received contaminants emerge at significantly uncertain time lags to a large array of discharge surfaces such as public supply, domestic and irrigation wells and streams. To support decision making in such complex regimes several approaches have been developed, which can be grouped into 3 categories: i) Index methods, ii)regression methods and iii) physically based methods. Among the three, physically based methods are considered more accurate, but at the cost of computational demand. In this work we present a physically based simulation framework which exploits the latest hardware and software developments to simulate large (>>1,000 km2) groundwater basins. First we simulate groundwater flow using a sufficiently detailed mesh to capture the spatial heterogeneity. To achieve optimal mesh quality we combine adaptive mesh refinement with the nonlinear solution for unconfined flow. Starting from a coarse grid the mesh is refined iteratively in the parts of the domain where the flow heterogeneity appears higher resulting in optimal grid. Secondly we simulate the nonpoint source pollution based on the detailed velocity field computed from the previous step. In our approach we use the streamline model where the 3D transport problem is decomposed into multiple 1D transport problems. The proposed framework is applied to simulate nonpoint source pollution in the Central Valley aquifer system, California.

  14. Hydrochemical modeling and assessment of groundwater contamination in northwest Sinai, Egypt.

    PubMed

    El Alfy, Mohamed

    2013-03-01

    This study aims to investigate groundwater geochemical characteristics, and to assess the effects of groundwater contamination in northwest Sinai, Egypt. A geographic information system, geochemical modeling, and statistical analyses tools were used. Twenty-five groundwater samples from a Quaternary aquifer were sampled. These water samples were analyzed for major, minor, and trace elements. The results of this study contribute to a better understanding of the hydrochemical characteristic as well as the anthropogenic processes of groundwater pollution. On the basis of these analyses, the geochemical parameters and the anomalous concentration of different elements enable the characterization of salinity sources of the brackish waters and the suspected sources of polluted water. Pollution sources are represented by waste disposal and agricultural activities as well as the probable upward leakage of highly saline water from the deeper aquifers and the saltwater intrusion. Pollution risk is high when the depth of the water table is shallow (0.3 to 15.0 m) and the aquifer has high hydraulic conductivity and poor matrix buffering capacity. PMID:23581236

  15. Vulnerability of recently recharged groundwater in principal [corrected] aquifers of the United States to nitrate contamination.

    PubMed

    Gurdak, Jason J; Qi, Sharon L

    2012-06-01

    Recently recharged water (defined here as <60 years old) is generally the most vulnerable part of a groundwater resource to nonpoint-source nitrate contamination. Understanding at the appropriate scale the interactions of natural and anthropogenic controlling factors that influence nitrate occurrence in recently recharged groundwater is critical to support best management and policy decisions that are often made at the aquifer to subaquifer scale. New logistic regression models were developed using data from the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program and National Water Information System for 17 principal aquifers of the U.S. to identify important source, transport, and attenuation factors that control nonpoint source nitrate concentrations greater than relative background levels in recently recharged groundwater and were used to predict the probability of detecting elevated nitrate in areas beyond the sampling network. Results indicate that dissolved oxygen, crops and irrigated cropland, fertilizer application, seasonally high water table, and soil properties that affect infiltration and denitrification are among the most important factors in predicting elevated nitrate concentrations. Important differences in controlling factors and spatial predictions were identified in the principal aquifer and national-scale models and support the conclusion that similar spatial scales are needed between informed groundwater management and model development. PMID:22582987

  16. Vulnerability of recently recharged groundwater in principal aquifers of the United States to nitrate contamination

    USGS Publications Warehouse

    Gurdak, Jason J.; Qi, Sharon L.

    2012-01-01

    Recently recharged water (defined here as <60 years old) is generally the most vulnerable part of a groundwater resource to nonpoint-source nitrate contamination. Understanding at the appropriate scale the interactions of natural and anthropogenic controlling factors that influence nitrate occurrence in recently recharged groundwater is critical to support best management and policy decisions that are often made at the aquifer to subaquifer scale. New logistic regression models were developed using data from the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program and National Water Information System for 17 principal aquifers of the U.S. to identify important source, transport, and attenuation factors that control nonpoint source nitrate concentrations greater than relative background levels in recently recharged groundwater and were used to predict the probability of detecting elevated nitrate in areas beyond the sampling network. Results indicate that dissolved oxygen, crops and irrigated cropland, fertilizer application, seasonally high water table, and soil properties that affect infiltration and denitrification are among the most important factors in predicting elevated nitrate concentrations. Important differences in controlling factors and spatial predictions were identified in the principal aquifer and national-scale models and support the conclusion that similar spatial scales are needed between informed groundwater management and model development.

  17. Groundwater pollution source characterization of an old landfill

    Microsoft Academic Search

    Peter Kjeldsen

    1993-01-01

    Only a few landfill investigations have focused on both the quantity and the quality of leachate as a source of groundwater pollution. The investigation of Vejen Landfill in Denmark included an introductionary historical survey (old maps, aerial photographs, interviews, etc.), leachate quality analysis, potential mapping of the groundwater surface below the landfill and leachate flow to surface waters and groundwater.

  18. Nonpoint Source Pollution from Animal Farming in Semi-Arid Regions: Spatio-Temporal Variability and Groundwater Monitoring Strategies 1

    Microsoft Academic Search

    T. Harter; R. D. Meyer; M. C. Mathews

    Nitrate contamination remains a ubiquitous groundwater pollution problem worldwide. Animal farming systems are among the major sources of groundwater nitrate. Little is known about the impact of dairy farming practices on water quality in the extensive alluvial aquifers underlying many animal farming regions in the United States and elsewhere. The objective of this work is to characterize and assess nitrate

  19. Nitrate contamination of groundwater in two areas of the Cameroon Volcanic Line (Banana Plain and Mount Cameroon area)

    NASA Astrophysics Data System (ADS)

    Ako, Andrew Ako; Eyong, Gloria Eneke Takem; Shimada, Jun; Koike, Katsuaki; Hosono, Takahiro; Ichiyanagi, Kimpei; Richard, Akoachere; Tandia, Beatrice Ketchemen; Nkeng, George Elambo; Roger, Ntankouo Njila

    2014-06-01

    Water containing high concentrations of nitrate is unfit for human consumption and, if discharging to freshwater or marine habitats, can contribute to algal blooms and eutrophication. The level of nitrate contamination in groundwater of two densely populated, agro-industrial areas of the Cameroon Volcanic Line (CVL) (Banana Plain and Mount Cameroon area) was evaluated. A total of 100 samples from boreholes, open wells and springs (67 from the Banana Plain; 33 from springs only, in the Mount Cameroon area) were collected in April 2009 and January 2010 and analyzed for chemical constituents, including nitrates. The average groundwater nitrate concentrations for the studied areas are: 17.28 mg/l for the Banana Plain and 2.90 mg/l for the Mount Cameroon area. Overall, groundwaters are relatively free from excessive nitrate contamination, with nitrate concentrations in only 6 % of groundwater resources in the Banana Plain exceeding the maximum admissible concentration for drinking water (50 mg/l). Sources of NO3 - in groundwater of this region may be mainly anthropogenic (N-fertilizers, sewerage, animal waste, organic manure, pit latrines, etc.). Multivariate statistical analyses of the hydrochemical data revealed that three factors were responsible for the groundwater chemistry (especially, degree of nitrate contamination): (1) a geogenic factor; (2) nitrate contamination factor; (3) ionic enrichment factor. The impact of anthropogenic activities, especially groundwater nitrate contamination, is more accentuated in the Banana Plain than in the Mount Cameroon area. This study also demonstrates the usefulness of multivariate statistical analysis in groundwater study as a supplementary tool for interpretation of complex hydrochemical data sets.

  20. Prioritization of ground water contaminants and sources

    Microsoft Academic Search

    R. C. Knox; L. W. Canter

    1996-01-01

    The objective of this research was to identify chemical, physical, bacteriological, and viral contaminants, and their sources, which present the greatest health threat in public ground water supplies in the USA; and to classify (prioritize) such contaminants and relative to their health concerns. The developed contaminant prioritization methodology was based on frequency of occurrence and adverse health effects. Adverse health

  1. Screening of French groundwater for regulated and emerging contaminants.

    PubMed

    Lopez, Benjamin; Ollivier, Patrick; Togola, Anne; Baran, Nicole; Ghestem, Jean-Philippe

    2015-06-15

    Nationwide screening of 411 emerging contaminants and other regulated compounds, including parent molecules and transformation products (TPs) having various uses and origins, was done at 494 groundwater sites throughout France during two sampling campaigns in the Spring and the Fall of 2011. One hundred and eighty substances (44% of the targeted compounds) were quantified in at least one sampling point. These included pharmaceuticals, industrial products, pesticides, their transformation products and other emerging compounds. Fifty-five compounds were quantified in more than 1% of the samples. Both regulated and emerging compounds were found. Among the unregulated compounds, acetaminophen, carbamazepine, perfluorinated compounds, dioxins/furans, tolyltriazole, bisphenol A, triazine transformation products, and caffeine were quantified in more than 10% of the samples analyzed. Concentrations exceeding the threshold of toxicological concern of 0.1 ?g/L were found for tolyltriazole, bisphenol A and some of the triazine transformation products (DEDIA). These new results should help the water resource managers and environmental regulators develop sound policies regarding the occurrence and distribution of regulated and emerging contaminants in groundwater. PMID:25782024

  2. Urban groundwater contamination by residues of UV filters.

    PubMed

    Jurado, Anna; Gago-Ferrero, Pablo; Vàzquez-Suñé, Enric; Carrera, Jesus; Pujades, Estanislao; Díaz-Cruz, M Silvia; Barceló, Damià

    2014-04-30

    The occurrence and fate of UV filters (UV F) in an urban aquifer in correlation with (1) the spatial distribution of UV F in Barcelona's groundwater, (2) the depth of the groundwater sample, (3) the physicochemical properties of the target compounds, (4) the recharge sources, and (5) the redox conditions of the Barcelona aquifers, were studied for the first time. The highest groundwater concentrations and the largest number of detected UV F were observed in an aquifer recharged by a polluted river (around 55 ng/L in SAP-4). In contrast, the urbanized areas had lower concentrations (around 20 ng/L in MPSP-1). Two pathways can be identified for UV F to enter the aquifers: (1) leakage of row sewage from the sewage network in urbanized areas and (2) wastewater treatment plant (WWTP) effluents discharged into the river. Measured concentrations of UV F were significantly much lower than those estimated from the waste water proportion in groundwater samples suggesting that UV F might undergo transformation processes in both reducing and oxidizing conditions. PMID:24632366

  3. REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER

    SciTech Connect

    B. STRIETELMEIR; ET AL

    2000-12-01

    A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), and extremely inexpensive and easy to emplace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate and perchlorate in groundwater from Mortandad Canyon at Los Alamos National Laboratory (LANL). This groundwater was obtained from a monitoring well, MCO-5, which is located in the flowpath of the discharge waters from the LANL Radioactive Liquid Waste Treatment Facility (RLWTF). Water with elevated nitrate levels has been discharged from this plant for many years, until recently when the nitrate levels have been brought under the discharge limits. However, the historical discharge has resulted in a nitrate plume in the alluvial groundwater in this canyon. The LANL Multi-Barrier project was initiated this past year to develop a system of barriers that would prevent the transport of radionuclides, metals, colloids and other contaminants, including nitrate and perchlorate, further down the canyon in order to protect populations down-gradient. The biobarrier. will be part of this Multi-Barrier system. We have demonstrated the destruction of nitrate at levels up to 6.5-9.7 mhl nitrate (400-600 mg/L), and that of perchlorate at levels of about 4.3 {micro}M perchlorate (350 ppb). We have quantified the populations of microorganisms present in the biofilm that develops on the biobarrier. The results of this research will be discussed along with other potential applications of this system.

  4. Mechanisms for groundwater contamination by UCG: preliminary conclusions from the Hoe Creek study

    Microsoft Academic Search

    F. T. Wang; S. W. Mead; D. H. Stuermer

    1982-01-01

    We have monitored groundwater quality changes in approximately 60 wells constructed near the 3 underground coal gasification (UCG) experiments carried out at our Hoe Creek site in northeastern Wyoming. A broad range of residual gasification products are introduced into the groundwater system as a result of the UCG process. These groundwater contaminants may be of environmental significance if they find

  5. Development of type transfer functions for regional-scale nonpoint source groundwater vulnerability assessments

    Microsoft Academic Search

    Iris T. Stewart; Keith Loague

    2003-01-01

    Groundwater vulnerability assessments of nonpoint source agrochemical contamination at regional scales are either qualitative in nature or require prohibitively costly computational efforts. By contrast, the type transfer function (TTF) modeling approach for vadose zone pesticide leaching presented here estimates solute concentrations at a depth of interest, only uses available soil survey, climatic, and irrigation information, and requires minimal computational cost

  6. Assessing ground-water vulnerability to contamination: Providing scientifically defensible information for decision makers

    USGS Publications Warehouse

    Focazio, Michael J.; Reilly, Thomas E.; Rupert, Michael G.; Helsel, Dennis R.

    2002-01-01

    Throughout the United States increasing demands for safe drinking water and requirements to maintain healthy ecosystems are leading policy makers to ask complex social and scientific questions about how to assess and manage our water resources. This challenge becomes particularly difficult as policy and management objectives require scientific assessments of the potential for ground-water resources to become contaminated from anthropogenic, as well as natural sources of contamination. Assessments of the vulnerability of ground water to contamination range in scope and complexity from simple, qualitative, and relatively inexpensive approaches to rigorous, quantitative, and costly assessments. Tradeoffs must be carefully considered among the competing influences of the cost of an assessment, the scientific defensibility, and the amount of acceptable uncertainty in meeting the objectives of the water-resource decision maker.

  7. Pathogens in Dairy Farming: Source Characterization and Groundwater Impacts

    NASA Astrophysics Data System (ADS)

    Atwill, E. R.; Watanabe, N.; Li, X.; Hou, L.; Harter, T.; Bergamaschi, B.

    2007-12-01

    Intense animal husbandry is of growing concern as a potential contamination source of enteric pathogens as well as antibiotics. To assess the public health risk from pathogens and their hydrologic pathways, we hypothesize that the animal farm is not a homogeneous diffuse source, but that pathogen loading to the soil and, therefore, to groundwater varies significantly between the various management units of a farm. A dairy farm, for example, may include an area with calf hutches, corrals for heifers of various ages, freestalls and exercise yards for milking cows, separate freestalls for dry cows, a hospital barn, a yard for collection of solid manure, a liquid manure storage lagoon, and fields receiving various amounts of liquid and solid manure. Pathogen shedding and, hence, therapeutic and preventive pharmaceutical treatments vary between these management units. We are implementing a field reconnaissance program to determine the occurrence of three different pathogens ( E. coli, Salmonella, Campylobacter) and one indicator organism ( Enterococcus) at the ground-surface and in shallow groundwater of seven different management units on each of two farms, and in each of four seasons (spring/dry season, summer/irrigation season, fall/dry season, winter/rainy season). Initial results indicate that significant differences exist in the occurrence of these pathogens between management units and between organisms. These differences are weakly reflected in their occurrence in groundwater, despite the similarity of the shallow geologic environment across these sites. Our results indicate the importance of differentiating sources within a dairy farm and the importance of understanding subsurface transport processes for these pathogens.

  8. Efficient Bayesian experimental design for contaminant source identification

    NASA Astrophysics Data System (ADS)

    Zhang, Jiangjiang; Zeng, Lingzao; Chen, Cheng; Chen, Dingjiang; Wu, Laosheng

    2015-01-01

    In this study, an efficient full Bayesian approach is developed for the optimal sampling well location design and source parameters identification of groundwater contaminants. An information measure, i.e., the relative entropy, is employed to quantify the information gain from concentration measurements in identifying unknown parameters. In this approach, the sampling locations that give the maximum expected relative entropy are selected as the optimal design. After the sampling locations are determined, a Bayesian approach based on Markov Chain Monte Carlo (MCMC) is used to estimate unknown parameters. In both the design and estimation, the contaminant transport equation is required to be solved many times to evaluate the likelihood. To reduce the computational burden, an interpolation method based on the adaptive sparse grid is utilized to construct a surrogate for the contaminant transport equation. The approximated likelihood can be evaluated directly from the surrogate, which greatly accelerates the design and estimation process. The accuracy and efficiency of our approach are demonstrated through numerical case studies. It is shown that the methods can be used to assist in both single sampling location and monitoring network design for contaminant source identifications in groundwater.

  9. ASSESSING POTENTIAL EXPOSURES FROM ROUTINE USE OF VOC-CONTAMINATED GROUNDWATER

    EPA Science Inventory

    Three identical experiments were conducted in a single residence to assess potential exposures that may result from the routine household use of VOC-contaminated groundwater. Each experiment was based on a single 20-min shower using contaminated groundwater containing 185-367 ug/...

  10. Estimation of historical groundwater contaminant distribution using the adjoint state method applied to geostatistical inverse modeling

    Microsoft Academic Search

    Anna M. Michalak

    2004-01-01

    (1) As the incidence of groundwater contamination continues to grow, a number of inverse modeling methods have been developed to address forensic groundwater problems. In this work the geostatistical approach to inverse modeling is extended to allow for the recovery of the antecedent distribution of a contaminant at a given point back in time, which is critical to the assessment

  11. Assessment of groundwater contamination by nitrate leaching from intensive vegetable cultivation using geographical information system

    Microsoft Academic Search

    Insaf S. Babiker; Mohamed A. A. Mohamed; H. Terao; Kikuo Kato; Keiichi Ohta

    2004-01-01

    This study employed the Geographical Information System (GIS) technology to investigate nitrate contamination of groundwater by agrochemical fertilizers in the Kakamigahara Heights, Gifu Prefecture, central Japan. Thematic information and chemical data of groundwater from the Heights were analyzed in a GIS environment to study the extent and variation of nitrate contamination and to establish spatial relationships with responsible land use

  12. Arsenic Groundwater Contamination in Middle Ganga Plain, Bihar, India: A Future Danger?

    Microsoft Academic Search

    Dipankar Chakraborti; Subhash C. Mukherjee; Shyamapada Pati; Mrinal K. Sengupta; Mohammad M. Rahman; Uttam K. Chowdhury; Dilip Lodh; Chitta R. Chanda; Anil K. Chakraborti; Gautam K. Basu

    2003-01-01

    The pandemic of arsenic poisoning due to contaminated groundwater in West Bengal, India, and all of Bangladesh has been thought to be limited to the Ganges Delta (the Lower Ganga Plain), despite early survey reports of arsenic contamination in groundwater in the Union Territory of Chandigarh and its surroundings in the northwestern Upper Ganga Plain and recent findings in the

  13. Groundwater surface mapping informs sources of catchment baseflow

    NASA Astrophysics Data System (ADS)

    Costelloe, J. F.; Peterson, T. J.; Halbert, K.; Western, A. W.; McDonnell, J. J.

    2014-11-01

    Groundwater discharge is a major contributor to stream baseflow. Quantifying this flux is difficult, despite its considerable importance to water resource management and evaluation of the effects of groundwater extraction on streamflow. It is important to be able to differentiate between contributions to streamflow from regional groundwater discharge (more susceptible to groundwater extraction) compared to interflow processes (arguably less susceptible to groundwater extraction). Here we explore the use of unconfined groundwater surface mapping as an independent dataset to constrain estimates of groundwater discharge to streamflow using traditional digital filter and tracer techniques. We developed groundwater surfaces from 98 monitoring bores using Kriging with external drift. Baseflow estimates at the catchment outlet were made using the Eckhardt digital filter approach and tracer data mixing analysis using major ion and stable isotope signatures. Our groundwater mapping approach yielded two measures (percentage area intersecting the land surface and monthly change in saturated volume) that indicated that digital filter-derived baseflow significantly exceeded probable groundwater discharge during the high flow period of spring to early summer. Tracer analysis was not able to resolve contributions from ungauged tributary flows (sourced from either shallow flow paths, i.e. interflow and perched aquifer discharge, or regional groundwater discharge) and regional groundwater. Groundwater mapping was able to identify ungauged sub-catchments where regional groundwater discharge was too deep to contribute to tributary flow and thus where shallow flow paths dominated the tributary flow. Our results suggest that kriged unconfined groundwater surfaces provide a useful, empirical and independent dataset for investigating sources of fluxes contributing to baseflow and identifying periods where baseflow analysis may overestimate groundwater discharge to streamflow.

  14. Groundwater contamination by nitrates associated with intensive potato culture in Québec.

    PubMed

    Levallois, P; Thériault, M; Rouffignat, J; Tessier, S; Landry, R; Ayotte, P; Girard, M; Gingras, S; Gauvin, D; Chiasson, C

    1998-06-30

    In rural areas, groundwater contamination by nitrates is a problem related to the spreading of organic and chemical fertilizers by farmers and, to some extent, to effluents from domestic sewage systems. Health effects of groundwater contamination by nitrates have been assessed several times and may lead to important consequences for infants. Following pressures from citizens in 1990, a survey of well water quality around potato fields of the Portneuf county (Québec) found that nitrate contamination was frequently above the 10 mg-N/1 standard. Because this first survey was limited to areas of intensive potato culture, it was not possible to evaluate the real impact on the groundwater quality for the whole county and the subsequent public health intervention was spread over the entire region. A second survey was carried out in 1995 to reevaluate the situation using random sampling methods. This latter study took into account drinking water habits of the population, the relative importance of potato culture as a source of nitrogen loading, the effects of soil types, and waste-water disposal systems as well as land use on nitrate concentration in private well water. The data analysis was carried out by combining GIS and statistical methods to test hypotheses about the spatial relationship linking measured nitrate concentrations with their immediate environment. This paper presents the major findings from this second study which confirm the impact of intensive potato culture on groundwater nitrate concentrations, mainly localized in sandy soil areas within 2 km of fields. Finally, it illustrates the usefulness of GIS to focus public health interventions. PMID:9695174

  15. Wellhead treatment costs for groundwater contaminated with pesticides: A preliminary analysis for pineapple in Hawaii

    NASA Astrophysics Data System (ADS)

    Leon-Guerrero, Ephraim D.; Loague, Keith; Green, Richard E.

    1994-01-01

    In Hawaii, trace concentrations of pesticides used in the production of pineapple were found in the groundwater supplies of Mililani Town in the Pearl Harbor Basin on the island of Oahu. Groundwater serves as the major source of drinking water and residents pay for wellhead treatment of the contaminated water, via their monthly water bill. The agricultural chemical users within the Pearl Harbor Basin do not include these wellhead treatment costs in their production costs. The agricultural industry benefits from using pesticides but does not pay the entire societal cost of using these chemicals. In this study we evaluate the specific financial cost of wellhead treatment, and not the economic value of groundwater. While wellhead treatment costs could conceivably be shared by several parties, this study focuses on the financial impact of the pineapple industry alone. This study factors annual wellhead treatment costs into annual pineapple production costs to measure the effect on annual financial return from pineapple production. Wellhead treatment costs are calculated from the existing granulated activated carbon (GAC) water treatment facility for Millilani Wells I and II. Pineapple production costs are estimated from previous cost of production studies. The inclusion of wellhead treatment costs produces different production-cost results, depending on the scale of analysis. At the local scale, the Mililani wellhead treatment costs can be factored into the production costs of the pineapple fields, which were probably responsible for contamination of the Mililani Wells, without causing a deficit in economic return. At the larger regional scale, however, the return from all of the pineapple grown in the Pearl Harbor Basin can not sustain the cost of wellhead treatmentfor the entire water supply of the basin. Recommendations point to the prevention of groundwater contamination as more cost-effective measure than wellhead treatment.

  16. Different Strategies for Biological Remediation of Perchlorate Contaminated Groundwater

    E-print Network

    Wang, Yue

    2012-01-01

    barrier for the treatment of arsenic in groundwater: Part 1.Arsenic, iron and manganese were present the groundwater atGroundwater Treatment Wall Figure2.2 Schematic of a permeable reactive barrier (PRB) TCE, hexavalent chromium, arsenic

  17. Predicting geogenic arsenic contamination in shallow groundwater of south Louisiana, United States.

    PubMed

    Yang, Ningfang; Winkel, Lenny H E; Johannesson, Karen H

    2014-05-20

    Groundwater contaminated with arsenic (As) threatens the health of more than 140 million people worldwide. Previous studies indicate that geology and sedimentary depositional environments are important factors controlling groundwater As contamination. The Mississippi River delta has broadly similar geology and sedimentary depositional environments to the large deltas in South and Southeast Asia, which are severely affected by geogenic As contamination and therefore may also be vulnerable to groundwater As contamination. In this study, logistic regression is used to develop a probability model based on surface hydrology, soil properties, geology, and sedimentary depositional environments. The model is calibrated using 3286 aggregated and binary-coded groundwater As concentration measurements from Bangladesh and verified using 78 As measurements from south Louisiana. The model's predictions are in good agreement with the known spatial distribution of groundwater As contamination of Bangladesh, and the predictions also indicate high risk of As contamination in shallow groundwater from Holocene sediments of south Louisiana. Furthermore, the model correctly predicted 79% of the existing shallow groundwater As measurements in the study region, indicating good performance of the model in predicting groundwater As contamination in shallow aquifers of south Louisiana. PMID:24779344

  18. Volatilized tritiated water vapor in the vicinity of exposed tritium contaminated groundwater

    SciTech Connect

    Dunn, D.L.; Carlton, B.; Hunter, C.; McAdams, T.

    1994-06-01

    Water vapor tritium concentrations in air above a known source of tritiated water can be estimated. Estimates should account for the mechanisms of evaporation and condensation at the water surface and water species exchange, and are typically applicable under a broad range of wind, temperature and humidity conditions. An estimate of volatilized tritium water vapor was made for a known outcropping of tritium contaminated groundwater at the Savannah River Site (SRS) old F-Area effluent stream. In order to validate this estimate and the associated dose calculation, sampling equipment was fabricated, tested, and installed at the effluent stream. The estimate and the dose calculation were confirmed using data from samples collected.

  19. Ground-water contamination in East Bay Township, Michigan

    USGS Publications Warehouse

    Twenter, F.R.; Cummings, T.R.; Grannemann, N.G.

    1985-01-01

    Glacial deposits, as much as 360 feet thick, underlie the study area. The upper 29 to 118 feet, a sand and gravel unit, is the aquifer tapped by all wells in the area. This unit is underlain by impermeable clay that is at least 100 feet thick. Ground-water flow is northeastward at an estimated rate of 2 to 5 feet per day. Hydraulic conductivities in the aquifer range from 85 to 250 feet per day; 120 feet per day provided the best match of field data in a ground-water flow model. The depth to water ranged from 1 to 20 feet. Chemical analyses indicate that ground water is contaminated with organic chemicals from near the Hangar/Administration building at the U.S. Coast Guard Air Station at East Bay, about 4,300 feet northeast. The plume, which follows ground-water flow lines, ranges from 180 to 400 feet wide. In the upper reach of the plume, hydrocarbons less dense than water occur at the surface of the water table; they move downward in the aquifer as they move toward east Bay. Maximum concentrations of the major organic compounds include: benzene, 3,390 ug/L; toluene, 55,500 ug/L; xylene, 3,900 ug/L, tetrachloroethylene, 3,410 ug/L; amd bis (2-ethyl hexyl) phthalate, 2,100 ug/L. Soils are generally free of these hydrocarbons; however, in the vicinity of past drum storage, aircraft maintenance operations, and fuel storage and dispensing , as much as 1,100 ug/kg of tetrachloroethylene and 1,500 ug/kg of bis (-ethyl hexyl) phthalate were detected. At a few locations higher molecular weight hydrocarbons, characteristic of petroleum distillates were found. (USGS)

  20. Modeling uranium transport in acidic contaminated groundwater with base addition

    SciTech Connect

    Zhang, Fan [Institute of Tibetan Plateau Research, Chinese Academy of Sciences; Luo, Wensui [ORNL; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Brooks, Scott C [ORNL; Watson, David B [ORNL; Jardine, Philip [University of Tennessee, Knoxville (UTK); Gu, Baohua [ORNL

    2011-01-01

    This study investigates reactive transport modeling in a column of uranium(VI)-contaminated sediments with base additions in the circulating influent. The groundwater and sediment exhibit oxic conditions with low pH, high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U and various metal cations. Preliminary batch experiments indicate that additions of strong base induce rapid immobilization of U for this material. In the column experiment that is the focus of the present study, effluent groundwater was titrated with NaOH solution in an inflow reservoir before reinjection to gradually increase the solution pH in the column. An equilibrium hydrolysis, precipitation and ion exchange reaction model developed through simulation of the preliminary batch titration experiments predicted faster reduction of aqueous Al than observed in the column experiment. The model was therefore modified to consider reaction kinetics for the precipitation and dissolution processes which are the major mechanism for Al immobilization. The combined kinetic and equilibrium reaction model adequately described variations in pH, aqueous concentrations of metal cations (Al, Ca, Mg, Sr, Mn, Ni, Co), sulfate and U(VI). The experimental and modeling results indicate that U(VI) can be effectively sequestered with controlled base addition due to sorption by slowly precipitated Al with pH-dependent surface charge. The model may prove useful to predict field-scale U(VI) sequestration and remediation effectiveness.

  1. Baseline risk assessment of groundwater contamination at the Uranium Mill Tailings Site near Gunnison, Colorado

    SciTech Connect

    Not Available

    1993-12-01

    This Baseline Risk Assessment of Groundwater Contamination at the Uranium Mill Tailings Site Near Gunnison, Colorado evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells. This risk assessment evaluates the most contaminated monitor wells at the processing site. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium.

  2. Evaluating a groundwater supply contamination incident attributed to Marcellus Shale gas development.

    PubMed

    Llewellyn, Garth T; Dorman, Frank; Westland, J L; Yoxtheimer, D; Grieve, Paul; Sowers, Todd; Humston-Fulmer, E; Brantley, Susan L

    2015-05-19

    High-volume hydraulic fracturing (HVHF) has revolutionized the oil and gas industry worldwide but has been accompanied by highly controversial incidents of reported water contamination. For example, groundwater contamination by stray natural gas and spillage of brine and other gas drilling-related fluids is known to occur. However, contamination of shallow potable aquifers by HVHF at depth has never been fully documented. We investigated a case where Marcellus Shale gas wells in Pennsylvania caused inundation of natural gas and foam in initially potable groundwater used by several households. With comprehensive 2D gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOFMS), an unresolved complex mixture of organic compounds was identified in the aquifer. Similar signatures were also observed in flowback from Marcellus Shale gas wells. A compound identified in flowback, 2-n-Butoxyethanol, was also positively identified in one of the foaming drinking water wells at nanogram-per-liter concentrations. The most likely explanation of the incident is that stray natural gas and drilling or HF compounds were driven ?1-3 km along shallow to intermediate depth fractures to the aquifer used as a potable water source. Part of the problem may have been wastewaters from a pit leak reported at the nearest gas well pad-the only nearby pad where wells were hydraulically fractured before the contamination incident. If samples of drilling, pit, and HVHF fluids had been available, GCxGC-TOFMS might have fingerprinted the contamination source. Such evaluations would contribute significantly to better management practices as the shale gas industry expands worldwide. PMID:25941400

  3. Prediction of contamination potential of groundwater arsenic in Cambodia, Laos, and Thailand using artificial neural network.

    PubMed

    Cho, Kyung Hwa; Sthiannopkao, Suthipong; Pachepsky, Yakov A; Kim, Kyoung-Woong; Kim, Joon Ha

    2011-11-01

    The arsenic (As) contamination of groundwater has increasingly been recognized as a major global issue of concern. As groundwater resources are one of most important freshwater sources for water supplies in Southeast Asian countries, it is important to investigate the spatial distribution of As contamination and evaluate the health risk of As for these countries. The detection of As contamination in groundwater resources, however, can create a substantial labor and cost burden for Southeast Asian countries. Therefore, modeling approaches for As concentration using conventional on-site measurement data can be an alternative to quantify the As contamination. The objective of this study is to evaluate the predictive performance of four different models; specifically, multiple linear regression (MLR), principal component regression (PCR), artificial neural network (ANN), and the combination of principal components and an artificial neural network (PC-ANN) in the prediction of As concentration, and to provide assessment tools for Southeast Asian countries including Cambodia, Laos, and Thailand. The modeling results show that the prediction accuracy of PC-ANN (Nash-Sutcliffe model efficiency coefficients: 0.98 (traning step) and 0.71 (validation step)) is superior among the four different models. This finding can be explained by the fact that the PC-ANN not only solves the problem of collinearity of input variables, but also reflects the presence of high variability in observed As concentrations. We expect that the model developed in this work can be used to predict As concentrations using conventional water quality data obtained from on-site measurements, and can further provide reliable and predictive information for public health management policies. PMID:21917287

  4. Protection of public water supplies from ground-water contamination. Seminar publication

    Microsoft Academic Search

    L. L. Graham; R. C. Heath; L. Hinkle; O. T. Love; J. F. McNabb

    1985-01-01

    The publication contains material from technology transfer seminars presented for the water-supply community. The document provides utility managers and operators, regulators and technical specialists with guidance for preventing contamination and alternatives for treating public ground-water supplies that are contaminated. An understanding of the processes that affect the movement and degradation of contaminants in the subsurface is essential for effective ground-water

  5. PRIORITIZATION OF GROUND WATER CONTAMINANTS AND SOURCES

    EPA Science Inventory

    The objective of this research was to identify chemical, physical, bacteriological, and viral contaminants, and their sources, which present the greatest health threat in public ground water supplies in the USA; and to classify (prioritize) such contaminants and relative to their...

  6. Characterization of Persistent Volatile Contaminant Sources in the Vadose Zone

    NASA Astrophysics Data System (ADS)

    Carroll, K. C.; Truex, M. J.; Brusseau, M. L.; Parker, K. R.; Mackley, R. D.; Rohay, V. J.

    2012-12-01

    Remediation activities over time will alter the subsurface distribution of contaminants and likely create significant changes in the source-zone architecture. A field method was demonstrated for use of data collected from multiple individual soil vapor extraction (SVE) system well tests to locate and characterize the distribution of persistent VOC sources in the vadose zone. Operational data collected at the Department of Energy's Hanford site were used to examine changes in source zone architecture over time due to SVE operation and to illustrate the source-zone characterization approach. Individual well test results confirmed a heterogeneous distribution of permeability and contaminant mass discharge throughout the vadose zone. The trends in mass discharge and concentration were analyzed to determine the location and extent of the primary source zone within a lower-permeability unit at the site. This information is useful to evaluate the performance of SVE operations, and support decisions concerning system alteration or closure based on risk assessments of the impact of vadose-zone sources on groundwater contamination or vapor intrusion.

  7. Characterization of Persistent Volatile Contaminant Sources in the Vadose Zone

    SciTech Connect

    Carroll, Kenneth C.; Truex, Michael J.; Brusseau, Mark L.; Parker, Kyle R.; Mackley, Rob D.; Rohay, Virginia J.

    2013-05-01

    Remediation activities over time will alter the subsurface distribution of contaminants and likely create significant changes in the source-zone architecture. A field method was demonstrated for use of data collected from multiple individual soil vapor extraction (SVE) system well tests to locate and characterize the distribution of persistent VOC sources in the vadose zone. Operational data collected at the Department of Energy’s Hanford site were used to examine source zone alteration over time due to SVE operation and to illustrate the source-zone characterization approach. Individual well test results confirmed a heterogeneous distribution of permeability and contaminant mass discharge throughout the vadose zone. The trends in mass discharge and concentration were analyzed to determine the location and extent of the primary source zone within a lower-permeability unit at the site. This information is useful to evaluate the performance of SVE operations, and support decisions concerning system alteration or closure based on risk assessments of the impact of vadose-zone sources on groundwater contamination or vapor intrusion.

  8. Geohydrologic reconnaissance of a ground-water contamination problem in the Argonne Road area near Spokane, Washington

    USGS Publications Warehouse

    Dion, N.P.

    1987-01-01

    Three domestic wells that withdraw groundwater from an alluvium-filled trough cut into granite were found to be contaminated with the organic solvents tetrachloroethene, trichloroethene, 1,1,1-trichloroethane, and 1 ,2-trans-dichloroethene. The suspected source of contamination is a nearby septic-tank sludge disposal area. There is concern that the affected aquifer is tributary to the Spokane aquifer, which has been accorded ' sole source ' status by the U.S. Environmental Protection Agency. Preliminary estimates suggest that groundwater in the area is moving toward the Spokane aquifer and that the transit time may range from 2.5 to 25 years. Because of longitudinal dispersion, however, the plume of contaminants may move at a faster rate than the ambient groundwater and may arrive at given destinations more quickly than calculated above. A literature search has indicated that the dissolved solute phase of the contaminants will not be significantly affected by sorption, volatilization, chemical activity, or biodegradation. Because of the preliminary nature of the investigation, many questions relating to the extent of contamination remain unanswered. A list of suggested additional studies to answer those questions and to refine and confirm the findings of this investigation is presented. (Author 's abstract)

  9. Risk-based prioritization methodology for the classification of groundwater pollution sources.

    PubMed

    Pizzol, Lisa; Zabeo, Alex; Critto, Andrea; Giubilato, Elisa; Marcomini, Antonio

    2015-02-15

    Water management is one of the EU environmental priorities and it is one of the most serious challenges that today's major cities are facing. The main European regulation for the protection of water resources is represented by the Water Framework Directive (WFD) and the Groundwater Directive (2006/118/EC) which require the identification, risk-based ranking and management of sources of pollution and the identification of those contamination sources that threaten the achievement of groundwater's good quality status. The aim of this paper is to present a new risk-based prioritization methodology to support the determination of a management strategy for the achievement of the good quality status of groundwater. The proposed methodology encompasses the following steps: 1) hazard analysis, 2) pathway analysis, 3) receptor vulnerability analysis and 4) relative risk estimation. Moreover, by integrating GIS functionalities and Multi Criteria Decision Analysis (MCDA) techniques, it allows to: i) deal with several sources and multiple impacted receptors within the area of concern; ii) identify different receptors' vulnerability levels according to specific groundwater uses; iii) assess the risks posed by all contamination sources in the area; and iv) provide a risk-based ranking of the contamination sources that can threaten the achievement of the groundwater good quality status. The application of the proposed framework to a well-known industrialized area located in the surroundings of Milan (Italy) is illustrated in order to demonstrate the effectiveness of the proposed framework in supporting the identification of intervention priorities. Among the 32 sources analyzed in the case study, three sources received the highest relevance score, due to the medium-high relative risks estimated for Chromium (VI) and Perchloroethylene. The case study application showed that the developed methodology is flexible and easy to adapt to different contexts, thanks to the possibility to introduce specific relevant parameters identified according to expert judgment and data availability. PMID:25437767

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

    NASA Astrophysics Data System (ADS)

    Vroblesky, Don A.; Yanosky, Thomas M.; Siegel, Frederic R.

    1992-03-01

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

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

    USGS Publications Warehouse

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

    1992-01-01

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

  12. 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.

  13. WATER RESOURCES MANAGEMENT IN THE REMEDIATION OF GROUNDWATER ARSENIC CONTAMINATION IN BANGLADESH

    Microsoft Academic Search

    Masud Karim

    Severe arsenic contamination of groundwater in Bangladesh has disrupted the idea of using shallow tube-wells for safe drinking water throughout the country. Millions of tube-wells that had been sunk in various parts of the country are now dispensing arsenic contaminated drinking water. As a result, thousands of people are suffering from arsenic related diseases. The severity of arsenic contamination necessitates

  14. Distribution of terminal electron-accepting processes in an aquifer having multiple contaminant sources

    USGS Publications Warehouse

    McMahon, P.B.; Bruce, B.W.

    1997-01-01

    Concentrations of electron acceptors, electron donors, and H2 in groundwater were measured to determine the distribution of terminal electron-accepting processes (TEAPs) in an alluvial aquifer having multiple contaminant sources. Upgradient contaminant sources included two separate hydrocarbon point sources, one of which contained the fuel oxygenate methyl tertbutyl ether (MTBE). Infiltrating river water was a source of dissolved NO31 SO4 and organic carbon (DOC) to the downgradient part of the aquifer. Groundwater downgradient from the MTBE source had larger concentrations of electron acceptors (dissolved O2 and SO4) and smaller concentrations of TEAP end products (dissolved inorganic C, Fe2+ and CH4) than groundwater downgradient from the other hydrocarbon source, suggesting that MTBE was not as suitable for supporting TEAPs as the other hydrocarbons. Measurements of dissolved H2 indicated that SO4 reduction predominated in the aquifer during a period of high water levels in the aquifer and river. The predominant TEAP shifted to Fe3+ reduction in upgradient areas after water levels receded but remained SO4 reducing downgradient near the river. This distribution of TEAPs is the opposite of what is commonly observed in aquifers having a single contaminant point source and probably reflects the input of Dec and SO4 to the aquifer from the river. Results of this study indicate that the distribution of TEAPs in aquifers having multiple contaminant sources depends on the composition and location of the contaminants and on the availability of electron acceptors.

  15. Human impacts on karst groundwater contamination deduced by coupled nitrogen with strontium isotopes in the Nandong Underground River System in Yunan, China.

    PubMed

    Jiang, Yongjun; Wu, Yuexia; Yuan, Daoxian

    2009-10-15

    With the rapid increase in population and economy, groundwater quality has degraded in the Nandong Underground River System (NURS), a typical karst underground river developed in carbonate rocks (limestone and dolomite), which is located in an agriculture-dominated area in the southeast Yunnan Province, China. Determining sources of contamination in the groundwater is an important first step toward us improving its quality by emission control. It is with this aim that we reviewed here the benefit of using a coupled isotopic approach (delta15N and 87Sr/86Sr) to trace the origin of contamination in groundwater. Thirty-six representative groundwater samples, which were collected at different aquifers and land use types, showed significant disparities for major element concentrations and Sr and N isotopic composition in the NURS. Nitrate, along with Cl- and SO4(2-) and some Na+ and K+, pollution of groundwater is a significant problem in the NURS. The joint use of nitrogen and strontium isotope systematics in each context deciphered the origin of contamination in groundwater in the NURS as agricultural fertilizers and sewage effluents. Therefore, an increase in knowledge of groundwater geochemistry by means of hydrochemical and isotopic data will be helpful for understanding water-rock interactions and the influence of human activities on the hydrogeochemical environment of karst groundwater and provide a scientific basis for protection and rational utilization of groundwater resources in karst regions. PMID:19921878

  16. Aerated treatment pond technology with biofilm promoting mats for the bioremediation of benzene, MTBE and ammonium contaminated groundwater

    Microsoft Academic Search

    Sven Jechalke; Carsten Vogt; Nils Reiche; Alessandro G. Franchini; Helko Borsdorf; Thomas R. Neu; Hans H. Richnow

    2010-01-01

    A novel aerated treatment pond for enhanced biodegradation of groundwater contaminants was tested under field conditions. Coconut fibre and polypropylene textiles were used to encourage the development of contaminant-degrading biofilms. Groundwater contaminants targeted for removal were benzene, methyl tert-butyl ether (MTBE) and ammonium. Here, we present data from the first 14 months of operation and compare contaminant removal rates, volatilization

  17. GWSCREEN: A semi-analytical model for assessment of the groundwater pathway from surface or buried contamination: Version 2.0 theory and user`s manual

    SciTech Connect

    Rood, A.S.

    1993-06-01

    GWSCREEN was developed for assessment of the groundwater pathway from leaching of radioactive and non radioactive substances from surface or buried sources. The code was designed for implementation in the Track I and Track II assessment of CERCLA (Comprehensive Environmental Response, Compensation and Liability Act) sites identified as low probability hazard at the Idaho National Engineering Laboratory (DOE, 1992). The code calculates the limiting soil concentration such that, after leaching and transport to the aquifer, regulatory contaminant levels in groundwater are not exceeded. The code uses a mass conservation approach to model three processes: contaminant release from a source volume, contaminant transport in the unsaturated zone, and contaminant transport in the saturated zone. The source model considers the sorptive properties and solubility of the contaminant. Transport in the unsaturated zone is described by a plug flow model. Transport in the saturated zone is calculated with a semi-analytical solution to the advection dispersion equation in groundwater. In Version 2.0, GWSCREEN has incorporated an additional source model to calculate the impacts to groundwater resulting from the release to percolation ponds. In addition, transport of radioactive progeny has also been incorporated. GWSCREEN has shown comparable results when compared against other codes using similar algorithms and techniques. This code was designed for assessment and screening of the groundwater pathway when field data is limited. It was not intended to be a predictive tool.

  18. Investigation of Contaminated Groundwater at Solid Waste Management Unit 12, Naval Weapons Station Charleston, North Charleston, South Carolina, 2008

    USGS Publications Warehouse

    Vroblesky, Don A.; Petkewich, Matthew D.

    2009-01-01

    The U.S. Geological Survey and the Naval Facilities Engineering Command Southeast investigated natural and engineered remediation of chlorinated volatile organic compound (VOC) groundwater contamination at Solid Waste Management Unit 12 at the Naval Weapons Station Charleston, North Charleston, South Carolina, beginning in 2000. The primary contaminants of interest in the study are tetrachloroethene, 1,1,1-trichloroethane, trichloroethene, cis-1,2-dichloroethene, vinyl chloride, 1,1-dichloroethane, and 1,1-dichloroethene. Engineered remediation aspects at the site consist of a zero-valent-iron permeable reactive barrier (PRB) installed in December 2002 intercepting the contamination plume and a phytoremediation test stand of loblolly pine trees planted in the source area in May 2003. The U.S. Geological Survey planted an additional phytoremediation test stand of loblolly pine trees on the upgradient side of the southern end of the PRB in February 2008. At least once during the summer, however, the trees were inadvertently mowed during lawn cutting activity. The PRB along the main axis of the contaminant plume appears to be actively removing contamination. In contrast to the central area of the PRB, the data from the southern end of the PRB indicate that contaminants are moving around the PRB. Concentrations in wells upgradient from the PRB showed a general decrease in VOC concentrations. VOC concentrations in some wells in the forest downgradient from the PRB showed a sharp increase in 2005, followed by a decrease in 2006. Farther downgradient in the forest, the VOC concentrations began to increase in 2007 and continued to increase into 2008. The VOC-concentration changes in groundwater beneath the forest appear to indicate movement of a groundwater-contaminant pulse through the forest. It also is possible that the data may represent lateral shifting of the plume in response to changes in groundwater-flow direction.

  19. Investigation of Ground-Water Contamination at Solid Waste Management Unit 12, Naval Weapons Station Charleston, North Charleston, South Carolina

    USGS Publications Warehouse

    Vroblesky, Don A.; Casey, Clifton C.; Petkewich, Matthew D.; Lowery, Mark A.; Conlon, Kevin J.; Harrelson, Larry G.

    2007-01-01

    The U.S. Geological Survey and the Naval Facilities Engineering Command Southeast investigated natural and engineered remediation of chlorinated volatile organic compound ground-water contamination at Solid Waste Management Unit 12 at the Naval Weapons Station Charleston, North Charleston, South Carolina. The primary contaminants of interest are tetrachloroethene, 1,1,1-trichloroethane, trichloroethene, cis-1,2-dichloroethene, vinyl chloride, 1,1-dichloroethane, and 1,1-dichloroethene. In general, the hydrogeology of Solid Waste Management Unit 12 consists of a surficial aquifer, composed of sand to clayey sand, overlain by dense clay that extends from about land surface to a depth of about 8 to 10 feet and substantially limits local recharge. During some months in the summer, evapotranspiration and limited local recharge result in ground-water level depressions in the forested area near wells 12MW-12S and 12MW-17S, seasonally reflecting the effects of evapotranspiration. Changes in surface-water levels following Hurricane Gaston in 2004 resulted in a substantial change in the ground-water levels at the site that, in turn, may have caused lateral shifting of the contaminant plume. Hydraulic conductivity, determined by slug tests, is higher along the axis of the plume in the downgradient part of the forests than adjacent to the plume, implying that there is some degree of lithologic control on the plume location. Hydraulic conductivity, hydraulic gradient, sulfur-hexafluoride measurements, and historical data indicate that ground-water flow rates are substantially slower in the forested area relative to upgradient areas. The ground-water contamination, consisting of chlorinated volatile organic compounds, extends eastward in the surficial aquifer from the probable source area near a former underground storage tank. Engineered remediation approaches include a permeable reactive barrier and phytoremediation. The central part of the permeable reactive barrier along the main axis of the contaminant plume appears to be actively removing contamination; however, ground-water contamination is moving around the southern end of the permeable reactive barrier. Changes in the contaminant concentrations along the path of ground-water transport reflect a complex variety of influences. Potential influences include dechlorination, sorption and desorption, transpirative removal by trees, lateral shifting of the plume, and the presence of zones of differing concentrations possibly reflecting one or more pulse releases of contamination from the source area. Near the source area at well 12MW-10S, volatile organic compound concentrations of cis-1,2-dichlorothene, vinyl chloride, 1,1-dichloroethane, and 1,1,1-trichloroethane continued an irregular decline, while tetrachloroethene and 1,1-dichloroethene showed marked fluctuations in concentration during 2005 and 2006. Volatile organic compound concentrations at well 12MW-03S continued to show decreasing concentrations with the June 2006 concentrations being the lowest yet recorded at that well for several volatile organic compounds. Concentration and delta carbon 13 data indicate that in the upgradient part of the plume, tetrachloroethene is being degraded to trichloroethene, which is being degraded to cis-1,2-dichloroethene, and cis-1,2-dichloroethene is accumulating faster than it is being depleted. Ground-water volatile organic compound concentrations also changed in some wells in the forested area in the midpart of the plume. Increasing tetrachloroethene and decreasing trichloroethene and 1,1-dichloroethene concentrations were observed at wells 12MW-05S and 12MW-29S, possibly reflecting a lateral shift in the axis of the contamination plume or an advancing contamination pulse. Substantial decreases in contamination occur in the forested area downgradient from well 12MW-05S. Probable major loss mechanisms in this area include evapotranspiration and sorption.

  20. UQ and Decision Making for Groundwater Contamination: A Measure-Theoretic Approach

    NASA Astrophysics Data System (ADS)

    Mattis, S. A.; Dawson, C.; Butler, T.

    2014-12-01

    The movement of contaminant plumes in underground aquifers is highly dependent on many hydrogeological parameters. We model the transport with an advection, diffusion, reaction system requiring the specification of porosity, flow direction, flow speed, dispersivities, and effects of geochemical reactions. It is often prohibitively expensive or impossible to make accurate and reliable measurements of these parameters in the field. It is also difficult to know the position and shape of a contaminant plume at a given time or the exact details of the source of the contamination, e.g. size, location, origin time, and magnitude. If decisions are to be made regarding contaminant remediation strategies or predictions of future contaminant concentrations in and near water-supply wells, then these uncertain hydrogeological and source parameters need to be analyzed and estimated. We utilize a measure-theoretic framework to formulate and solve the physics-based stochastic inverse problem to quantify the uncertainty for these parameters. We solve the model using both analytical and finite element solutions. We define quantities of interest (QoI) for the groundwater contaminant problem in terms of observable field measurements. We develop adjoint problems to compute accurate and reliable a posteriori error estimates of the QoIs. The adjoint solutions are also useful in the solution of the inverse problem. The measure-theoretic formulation and solution of the inverse problem and modeling framework define a solution as a probability measure on the parameter domain. In the typical case where the number of output quantities is less than the number of parameters, the inverse of the map from parameters to data defines a type of generalized contour map where the geometry plays a pivotal role in determining an optimal set of QoI. We determine and analyze solutions for geometrically distinct QoI defining reduced-dimension set-valued inverses for this measure-theoretic inverse framework.

  1. Impacts on groundwater recharge areas of megacity pumping: analysis of potential contamination of Kolkata, India, water supply

    USGS Publications Warehouse

    Sahu, Paulami; Michael, Holly A.; Voss, Clifford I.; Sikdar, Pradip K.

    2013-01-01

    Water supply to the world's megacities is a problem of quantity and quality that will be a priority in the coming decades. Heavy pumping of groundwater beneath these urban centres, particularly in regions with low natural topographic gradients, such as deltas and floodplains, can fundamentally alter the hydrological system. These changes affect recharge area locations, which may shift closer to the city centre than before development, thereby increasing the potential for contamination. Hydrogeological simulation analysis allows evaluation of the impact on past, present and future pumping for the region of Kolkata, India, on recharge area locations in an aquifer that supplies water to over 13 million people. Relocated recharge areas are compared with known surface contamination sources, with a focus on sustainable management of this urban groundwater resource. The study highlights the impacts of pumping on water sources for long-term development of stressed city aquifers and for future water supply in deltaic and floodplain regions of the world.

  2. Soil Nitrogen Mineralization Potential for Improved Fertilizer Recommendations and Decreased Nitrate Contamination of Groundwater

    E-print Network

    Franzluebbers, Alan; Haney, Richard; Hons, Frank

    In order to prevent overfertilization, which could lead to groundwater contamination, rapid and accurate soil testing procedures are needed to evaluate agricultural surface soils for their potential to mineralize C and N. Our objectives were...

  3. RAPID ASSESSMENT OF POTENTIAL GROUND-WATER CONTAMINATION UNDER EMERGENCY RESPONSE CONDITIONS

    EPA Science Inventory

    Emergency response actions at chemical spills and abandoned hazardous waste sites often require rapid assessment of the potential for groundwater contamination by the chemical or waste compound. This manual provides a rapid assessment methodology for performing such an evaluation...

  4. Soil Nitrogen Mineralization Potential for Improved Fertilizer Recommendations and Decreased Nitrate Contamination of Groundwater 

    E-print Network

    Franzluebbers, Alan; Haney, Richard; Hons, Frank

    1995-01-01

    In order to prevent overfertilization, which could lead to groundwater contamination, rapid and accurate soil testing procedures are needed to evaluate agricultural surface soils for their potential to mineralize C and N. ...

  5. Risk assessment of groundwater contamination from hydraulic fracturing fluid spills in Pennsylvania

    E-print Network

    Fletcher, Sarah Marie

    2012-01-01

    Fast-paced growth in natural gas production in the Marcellus Shale has fueled intense debate over the risk of groundwater contamination from hydraulic fracturing and the shale gas extraction process at large. While several ...

  6. IDENTIFYING AND PREDICTING DIVING PLUME BEHAVIOR AT GROUNDWATER SITES CONTAMINATED WITH MTBE: PART 1

    EPA Science Inventory

    In EPA Region 5, MTBE from leaking underground storage tanks (LUST) has contaminated groundwater. In some cases, drinking water supply wells have been impacted, which forced local communities to adopt expensive alternatives. Traditionally, LUST site characterizations have focus...

  7. BIODEGRADATION OF CREOSOTE AND PCP IN CONTAMINATED GROUNDWATER: CHEMICAL AND BIOLOGICAL ASSESSMENT

    EPA Science Inventory

    Shake flask studies examined rate and extent of biodegradation of pentachlorophenol (PCP) and 42 components of coal-tar creosote present in contaminated groundwater recovered from the American Creosote Works (ACW) superfund site, Pensacola, Florida. he ability of soil microorgani...

  8. PERMEABLE REACTIVE BARRIERS FOR IN-SITU TREATMENT OF ARSENIC-CONTAMINATED GROUNDWATER

    EPA Science Inventory

    Laboratory and field research has shown that permeable reactive barriers (PRBs) containing a variety of materials can treat arsenic (As) contaminated groundwater. Sites where these PRBs are located include a mine tailings facility, fertilizer and chemical manufacturing sites, a...

  9. Preliminary hydrogeologic assessment of a ground-water contamination area in Wolcott, Connecticut

    USGS Publications Warehouse

    Stone, J.R.; Casey, G.D.; Mondazzi, R.A.; Frick, T.W.

    1997-01-01

    Contamination of ground water by volatile organic compounds and inorganic constituents has been identified at a number of industrial sites in the Town of Wolcott, Connecticut. Contamination is also present at a municipal landfill in the City of Waterbury that is upgradient from the industrial sites in the local ground-water-flow system. The study area, which lies in the Western Highlands of Connecticut, is in the Mad River Valley, a tributary to the Naugatuck River. Geohydrologic units (aquifer materials) include unconsolidated glacial sediments (surficial materials) and fractured crystalline (metamorphic) bedrock. Surficial materials include glacial till, coarse-grained andfine-grained glacial stratified deposits, and postglacial floodplain alluvium and swamp deposits. The ground-water-flow system in the surficial aquifer is complex because the hydraulic properties of the surficial materials are highly variable. In the bedrock aquifer, ground water moves exclusively through fractures. Hydrologic characteristics of the crystalline bedrock-degree of confinement, hydraulic conductivity, storativity, and porosity-are poorly defined in the study area. Further study is needed to adequately assess ground-water flow and contaminant migration under current or past hydrologic conditions. All known water-supply wells in the study area obtain water from the bedrock aquifer. Twenty households in a hillside residential area on Tosun Road currently obtain drinking water from private wells tapping the bedrock aquifer. The extent of contamination in the bedrock aquifer and the potential for future contamination from known sources of contamination in the surficial aquifer is of concern to regulatory agencies. Previous investigations have identified ground-water contamination by volatile organic compounds at the Nutmeg Valley Road site area. Contamination has been associated with on-site disposal of heavy metals, chlorinated and non-chlorinated volatile organic compounds, and cyanide. Concentrations of volatile organic compounds detected in water samples collected from bedrock wells during 1981-95 at the Nutmeg Valley Road site area show a general downward trend through time. Water samples collected from wells completed in surficial materials were not collected systematically, and a trend in concentration cannot be identified.

  10. Bioremediation Of Groundwater Contaminated Wtih Gasoline Hydrocarbons And Oxygenates Using A Membrane-Based Reactor

    EPA Science Inventory

    The objective of this study was to operate a novel, field-scale, aerobic bioreactor and assess its performance in the ex situ treatment of groundwater contaminated with gasoline from a leaking underground storage tank in Pascoag, RI. The groundwater contained elevated concentrat...

  11. Tracking the sources of nitrate in groundwater using coupled nitrogen and boron isotopes: a synthesis.

    PubMed

    Widory, David; Petelet-Giraud, Emmanuelle; Négrel, Philippe; Ladouche, Bernard

    2005-01-15

    Nitrate (NO3) is one of the world's major pollutants of drinking water resources. Although recent European Directives have reduced input from intensive agriculture, NO3 levels in groundwater are approaching the drinking water limit of 50 mg L(-1) almost everywhere. Determining the sources of groundwater contamination is an important first step toward improving its quality by emission control. It is with this aim that we review here the benefit of using a coupled isotopic approach (delta15N and delta11B), in addition to conventional hydrogeological analyses, to trace the origin of NO3 in water. The studied watersheds include both fractured bedrock and alluvial (subsurface and deep) hydrogeological contexts. The joint use of nitrogen and boron isotope systematics in each context deciphers the origin of NO3 in the groundwater and allows a semi-quantification of the contributions of the respective pollution sources (mineral fertilizers, wastewater, and animal manure). PMID:15707054

  12. A pragmatic approach for estimation of source-zone emissions at LNAPL contaminated sites

    NASA Astrophysics Data System (ADS)

    Miles, B.; Maji, R.; Sudicky, E. A.; Teutsch, G.; Peter, A.

    2008-02-01

    When considering natural attenuation as a remediation strategy at a site contaminated by a light non-aqueous phase liquid (LNAPL), it is important to consider the emission of contaminants from the source zone. A quantification of source-zone emissions is essential both for comparison with down-gradient mass fluxes to provide an estimate of fractional mass flux reduction, as well as for estimating the source lifetime. Because the spatial distribution of LNAPL at a field site is strongly dependent on both the spill circumstances and the heterogeneity of the geologic materials, which can be problematic for in-situ determination, alternative methods for estimating source-zone emissions are needed. In this work, a three-dimensional multiphase flow and transport modelling approach is used to investigate the relationship between the lateral extent of an LNAPL body and the emission of contaminants to groundwater at a contaminated site. For simulations involving an LNAPL release in an aquifer comprised of heterogeneous porosity and permeability distributions that were generated geostatistically, it is shown that a simple linear relationship exists between the lateral extent of the LNAPL body in the capillary fringe and the emission to the aqueous phase. The parameters describing the relationship are found to be linear functions of the groundwater flow velocity and the vertical infiltration rate. This site-specific relationship provides a simple method to estimate contaminant emissions to groundwater at LNAPL contaminated sites.

  13. Long term (1960-2010) trends in groundwater contamination and salinization in the Ogallala aquifer in Texas

    NASA Astrophysics Data System (ADS)

    Chaudhuri, Sriroop; Ale, Srinivasulu

    2014-05-01

    Although numerous studies have expounded on depletion of the Ogallala aquifer, very few researchers have studied groundwater quality therein which relates to the ‘usability’ of available groundwater resources. The objective of this study was to elucidate regional trends in groundwater quality and salinization in the Ogallala aquifer, underlying 49 counties and two Groundwater Management Areas (GMA 1 and 2) in Texas, on a decadal scale between 1960 and 2010. Contrasting groundwater quality distinguished GMA 1 (northern Ogallala) from GMA 2 (southern Ogallala), and shallow wells (depth <50 m) from deep (>50 m) wells. The GMA 2 was characterized by pronounced groundwater nitrate (NO3-) contamination accompanied by elevated levels of sulfate (SO42-), chloride (Cl-) and salinity (TDS), marked by an abundance of mixed cation SO4-Cl and Na-Cl facies. In contrast, Ca-Mg-HCO3 and Ca-HCO3 facies prevailed in GMA 1 with substantially lower salinization, SO42-, Cl- and NO3 contamination. In shallow wells, more abundant in GMA 2, about 80% and 32% of observations exceeded the United State Environmental Protection Agency’s Secondary Maximum Contaminant Level (SMCL, 500 mg L-1) for total dissolved solids (TDS) and MCL (44 mg L-1) for NO3, respectively in the 2000s (2000-2010), with progressive increases in both parameters since the 1960s (1960-1969). Majority (>60%) of the shallow observations since the 1980s (1980-1989) have exceeded the natural background of 11 mg L-1 of NO3- indicating anthropogenic sources, The NO3- contamination was more apparent in domestic wells indicating substantial human health risk. Groundwater salinization in this aquifer resulted from a combination of natural (e.g. upwelling of highly mineralized groundwater from the underlying formations, seepage from playas and saline plumes, and evaporative enrichment) and anthropogenic processes (irrigated agriculture and hydrocarbon exploration activities). Natural processes were largely aggravated by anthropogenic practices such as lowering of hydraulic heads in the Ogallala aquifer due to prolonged irrigational pumping, inducing cross-formational flow from underlying highly mineralized older formations (Edwards Trinity (High Plains)) which led to groundwater mixing between the formations and rise in salinity levels in the Ogallala aquifer over time.

  14. Predicting long-term contamination potential of perched groundwater in a mine-waste heap using a random-walk method

    Microsoft Academic Search

    Catherine J. Gandy; Paul L. Younger

    2008-01-01

    Mine-waste heaps are potential long-term sources of contamination for surface-water courses and groundwater systems. Application of a novel physically based particle-tracking model to a mine-waste heap in northern England, UK, has enabled predictions to be made of the lifetime of contaminants leaching, revealing a pattern of source-mineral depletion. A mine-waste heap is conceptualised by a series of one-dimensional unsaturated ``columns''

  15. APPLYING MEMBRANE PROCESSES TO GROUNDWATER SOURCES FOR TRIHALOMETHANE PRECURSOR CONTROL

    EPA Science Inventory

    The use of membrane processes for controlling trihalomethanes (THMs) was investigated for Florida groundwater sources and one surface water source. All of the sources were used for public supply and had excessive THMs (>300 micrograms/L) in the finished water. The performance and...

  16. INDEPENDENT TECHNICAL EVALUATION AND RECOMMENDATIONS FOR CONTAMINATED GROUNDWATER AT THE DEPARTMENT OF ENERGY OFFICE OF LEGACY MANAGEMENT RIVERTON PROCESSING SITE

    SciTech Connect

    Looney, B.; Denham, M.; Eddy-Dilek, C.

    2014-05-06

    The U.S. Department of Energy Office of Legacy Management (DOE-LM) manages the legacy contamination at the Riverton, WY, Processing Site – a former uranium milling site that operated from 1958 to 1963. The tailings and associated materials were removed in 1988-1989 and contaminants are currently flushing from the groundwater. DOE-LM commissioned an independent technical team to assess the status of the contaminant flushing, identify any issues or opportunities for DOE-LM, and provide key recommendations. The team applied a range of technical frameworks – spatial, temporal, hydrological and geochemical – in performing the evaluation. In each topic area, an in depth evaluation was performed using DOE-LM site data (e.g., chemical measurements in groundwater, surface water and soil, water levels, and historical records) along with information collected during the December 2013 site visit (e.g., plant type survey, geomorphology, and minerals that were observed, collected and evaluated). A few of the key findings include: ? Physical removal of the tailings and associated materials reduced contaminant discharges to groundwater and reduced contaminant concentrations in the near-field plume. ? In the mid-field and far-field areas, residual contaminants are present in the vadose zone as a result of a variety of factors (e.g., evaporation/evapotranspiration from the capillary fringe and water table, higher water levels during tailings disposal, and geochemical processes). ? Vadose zone contaminants are widely distributed above the plume and are expected to be present as solid phase minerals that can serve as “secondary sources” to the underlying groundwater. The mineral sample collected at the site is consistent with thermodynamic predictions. ? Water table fluctuations, irrigation, infiltration and flooding will episodically solubilize some of the vadose zone secondary source materials and release contaminants to the groundwater for continued down gradient migration – extending the overall timeframe for flushing. ? Vertical contaminant stratification in the vadose zone and surficial aquifer will vary from location to location. Soil and water sampling strategies and monitoring well construction details will influence characterization and monitoring data. ? Water flows from the Wind River, beneath the Riverton Processing Site and through the plume toward the Little Wind River. This base flow pattern is influenced by seasonal irrigation and other anthropogenic activities, and by natural perturbations (e.g., flooding). ? Erosion and reworking of the sediments adjacent to the Little Wind River results in high heterogeneity and complex flow and geochemistry. Water flowing into oxbow lakes (or through areas where oxbow lakes were present in the past) will be exposed to localized geochemical conditions that favor chemical reduction (i.e., “naturally reduced zones”) and other attenuation processes. This attenuation is not sufficient to fully stabilize the plume or to reduce contaminant concentrations in the groundwater to target levels. Consistent with these observations, the team recommended increased emphasis on collecting data in the zones where secondary source minerals are projected to accumulate (e.g., just above the water table) using low cost methods such as x-ray fluorescence. The team also suggested several low cost nontraditional sources of data that have the potential to provide supplemental data (e.g., multispectral satellite imagery) to inform and improve legacy management decisions. There are a range of strategies for management of the legacy contamination in the groundwater and vadose zone near the Riverton Processing Site. These range from the current strategy, natural flushing, to intrusive remedies such as plume scale excavation of the vadose zone and pump & treat. Each option relates to the site specific conditions, issues and opportunities in a unique way. Further, each option has advantages and disadvantages that need to be weighed. Scoping evaluation was performed for three major classes

  17. Conceptual Models for Migration of Key Groundwater Contaminants Through the Vadose Zone and Into the Upper Unconfined Aquifer Below the B-Complex

    SciTech Connect

    Serne, R. Jeffrey; Bjornstad, Bruce N.; Keller, Jason M.; Thorne, Paul D.; Lanigan, David C.; Christensen, J. N.; Thomas, Gregory S.

    2010-07-01

    The B-Complex contains 3 major crib and trench disposal sites and 3 SST farms that have released nearly 346 mega-liters of waste liquids containing the following high groundwater risk drivers: ~14,000 kg of CN, 29,000 kg of Cr, 12,000 kg of U and 145 Ci of Tc-99. After a thorough review of available vadose zone sediment and pore water, groundwater plume, field gamma logging, field electrical resistivity studies, we developed conceptual models for which facilities have been the significant sources of the contaminants in the groundwater and estimated the masses of these contaminants remaining in the vadose zone and currently present in the groundwater in comparison to the totals released. This allowed us to make mass balance calculations on how consistent our knowledge is on the current deep vadose zone and groundwater distribution of contaminants. Strengths and weaknesses of the conceptual models are discussed as well as implications on future groundwater and deep vadose zone remediation alternatives. Our hypothesized conceptual models attribute the source of all of the cyanide and most of the Tc-99 currently in the groundwater to the BY cribs. The source of the uranium is the BX-102 tank overfill event and the source of most of the chromium is the B-7-A&B and B-8 cribs. Our mass balance estimates suggest that there are much larger masses of U, CN, and Tc remaining in the deep vadose zone within ~20 ft of the water table than is currently in the groundwater plumes below the B-Complex. This hypothesis needs to be carefully considered before future remediation efforts are chosen. The masses of these groundwater risk drivers in the the groundwater plumes have been increasing over the last decade and the groundwater plumes are migrating to the northwest towards the Gable Gap. The groundwater flow rate appears to flucuate in response to seasonal changes in hydraulic gradient. The flux of contaminants out of the deep vadose zone from the three proposed sources also appears to be transient such that the evolution of the contaminant plumes is transient.

  18. U.S. Geological Survey toxic Waste-Groundwater Contamination Program, fiscal year 1985

    USGS Publications Warehouse

    Ragone, S.E.

    1986-01-01

    In fiscal year 1982, the U S Geological Survey began an interdisciplinary research thrust entitled Toxic Waste-Groundwater Contamination Program The objective of the thrust was to provide earth sciences information necessary to evaluate and mitigate existing groundwater contamination problems resulting from the planned or inadvertant disposal of wastes and from certain land-use practices, and to improve future waste disposal and land-use practices The program supports process-oriented and interdisciplinary field research, and regional groundwater quality studies This article provides an overview of the current (Fiscal Year 1985) activities of the Toxic Waste Program ?? 1986 Springer-Verlag New York Inc.

  19. Evidence for Legacy Contamination of Nitrate in Groundwater of North Carolina Using Monitoring and Private Well Data Models

    NASA Astrophysics Data System (ADS)

    Messier, K. P.; Kane, E.; Bolich, R.; Serre, M. L.

    2014-12-01

    Nitrate (NO3-) is a widespread contaminant of groundwater and surface water across the United States that has deleterious effects to human and ecological health. Legacy contamination, or past releases of NO3-, is thought to be impacting current groundwater and surface water of North Carolina. This study develops a model for predicting point-level groundwater NO3- at a state scale for monitoring wells and private wells of North Carolina. A land use regression (LUR) model selection procedure known as constrained forward nonlinear regression and hyperparameter optimization (CFN-RHO) is developed for determining nonlinear model explanatory variables when they are known to be correlated. Bayesian Maximum Entropy (BME) is then used to integrate the LUR model to create a LUR-BME model of spatial/temporal varying groundwater NO3- concentrations. LUR-BME results in a leave-one-out cross-validation r2 of 0.74 and 0.33 for monitoring and private wells, effectively predicting within spatial covariance ranges. The major finding regarding legacy sources NO3- in this study is that the LUR-BME models show the geographical extent of low-level contamination of deeper drinking-water aquifers is beyond that of the shallower monitoring well. Groundwater NO3- in monitoring wells is highly variable with many areas predicted above the current Environmental Protection Agency standard of 10 mg/L. Contrarily, the private well results depict widespread, low-level NO3-concentrations. This evidence supports that in addition to downward transport, there is also a significant outward transport of groundwater NO3- in the drinking water aquifer to areas outside the range of sources. Results indicate that the deeper aquifers are potentially acting as a reservoir that is not only deeper, but also covers a larger geographical area, than the reservoir formed by the shallow aquifers. Results are of interest to agencies that regulate surface water and drinking water sources impacted by the effects of legacy NO3- sources. Additionally, the results can provide guidance on factors affecting the point-level variability of groundwater NO3- and areas where monitoring is needed to reduce uncertainty. Lastly, LUR-BME predictions can be integrated into surface water models for more accurate management of non-point sources of nitrogen.

  20. Spreading due to Heterogeneity during Engineering Injection and Extraction for In Situ Remediation of Contaminated Groundwater

    NASA Astrophysics Data System (ADS)

    Piscopo, A. N.; Neupauer, R. M.; Mays, D. C.

    2012-12-01

    During in situ remediation of contaminated groundwater, spreading of the injected treatment solution increases its contact with the groundwater contaminant, leading to more opportunities for degradation reactions. Spreading can result from the heterogeneity of the porous media or from transient flows induced by pumping. Heterogeneity causes spreading by creating variations in fluid velocity that alter the trajectories of groundwater solutes. Transient flow fields can be induced in groundwater systems to stimulate spreading using engineered injection and extraction (EIE) of clean water at wells surrounding the treatment solution and contaminant plumes. Simulations of EIE in homogeneous media have shown that spreading due to EIE can enhance reaction during in situ remediation. This study demonstrates that spreading due to heterogeneity, which we represent as spatially-varying hydraulic conductivity, can augment the amount of reaction that occurs during EIE. Furthermore, we observe that the amount of reaction increases as the degree of heterogeneity increases.

  1. Modeling Three-Dimensional Groundwater Flow and Advective Contaminant Transport at a Heterogeneous Mountainous Site in Support of Remediation Strategy

    SciTech Connect

    Zhou, Quanlin; Birkholzer, Jens T.; Javandel, Iraj; Jordan, Preston D.

    2004-01-14

    A calibrated groundwater flow model for a contaminated site can provide substantial information for assessing and improving hydraulic measures implemented for remediation. A three-dimensional transient groundwater flow model was developed for a contaminated mountainous site, at which interim corrective measures were initiated to limit further spreading of contaminants. This flow model accounts for complex geologic units that vary considerably in thickness, slope, and hydrogeologic properties, as well as large seasonal fluctuations of the groundwater table and flow rates. Other significant factors are local recharge from leaking underground storm drains and recharge from steep uphill areas. The zonation method was employed to account for the clustering of high and low hydraulic conductivities measured in a geologic unit. A composite model was used to represent the bulk effect of thin layers of relatively high hydraulic conductivity found within bedrock of otherwise low conductivity. The inverse simulator ITOUGH2 was used to calibrate the model for the distribution of rock properties. The model was initially calibrated using data collected between 1994 and 1996. To check the validity of the model, it was subsequently applied to predicting groundwater level fluctuation and groundwater flux between 1996 and 1998. Comparison of simulated and measured data demonstrated that the model is capable of predicting the complex flow reasonably well. Advective transport was approximated using pathways of particles originating from source areas of the plumes. The advective transport approximation was in good agreement with the trend of contaminant plumes observed over the years. The validated model was then refined to focus on a subsection of the large system. The refined model was subsequently used to assess the efficiency of hydraulic measures implemented for remediation.

  2. 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 ...

  3. Heavy Metal Contamination of Soil and Groundwater at a Rail Rolling Stock Workshop

    Microsoft Academic Search

    Kwon-Ho Jeon; Jin-Yong Lee; Sang-Il Choi

    2008-01-01

    Soil and groundwater at a rail rolling stock workshop in a metropolitan city were contaminated with heavy metals including Pb, Cu and Cd. Prior to remedial design, a variety of field and laboratory investigations were conducted to characterize hydrogeologic conditions and to examine levels and extents of the contamination. The hydrogeology of the studied site near the Han River is

  4. Beneficial effects of plants in the remediation of soil and groundwater contaminated with organic materials

    Microsoft Academic Search

    J. F. Shimp; J. C. Tracy; L. C. Davis; E. Lee; W. Huang; L. E. Erickson; J. L. Schnoor

    1993-01-01

    The use of plants in remediation of soil and unconfined groundwater contaminated with organic materials is appealing for a variety of reasons: (1) plants provide a remediation strategy that utilizes solar energy; (2) vegetation is aesthetically pleasing; (3) plant samples can be harvested and tested as indicators of the level of remediation; (4) plants help contain the region of contamination

  5. Organic contaminants in groundwater mar an underground coal gasification site in northeastern Wyoming

    Microsoft Academic Search

    Daniel H. Stuermer; Douglas J. Ng; Clarence J. Morris

    1982-01-01

    Three groundwater samples collected near two underground coal gasification (UCG) sites 15 months after the end of gasification were analysed for dissolved organic contaminants. The contaminants consisted of phenols, aromatic carboxylic acids, aromatic hydrocarbons, ketones, aldehydes, pyridines, quinolines, isoquinolines, and aromatic amines. Concentrations ranged up to about 50 ppm with large variations both in the relative concentrations of acidic, neutral,

  6. DEMONSTRATION OF THE HIPOX ADVANCED OXIDATION TECHNOLOGY FOR THE TREATMENT OF MTBE-CONTAMINATED GROUNDWATER

    EPA Science Inventory

    The HiPOx technology is an advanced oxidation process that incorporates high-precision delivery of ozone and hydrogen peroxide to chemically destroy organic contaminants with the promise of minimizing bromate formation. A MTBE-contaminated groundwater from the Ventura County Nava...

  7. DEMONSTRATION OF THE HIPOX ADVANCED OXIDATION TECHNOLOGY FOR THE TREATMENT OF MTBE-CONTAMINATED GROUNDWATER

    EPA Science Inventory

    The HiPOx technology is an advanced oxidation process that incorporates high-precision delivery of ozone and hydrogen peroxide to chemically destroy organic contaminants with the promise of minimizing bromate formation. A MTBE-contaminated groundwater from the Ventura County Nav...

  8. 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...

  9. Probabilistic assessment of ground-water contamination. 2: Results of case study

    Microsoft Academic Search

    Jonathan D. Istok; Christopher A. Rautman

    1996-01-01

    The first paper in this series presented a geostatistical framework for obtaining a probabilistic assessment of ground-water contamination. This paper presents the results of a case study that applies this framework to define the spatial extent and severity of nitrate and Dacthal (dimethyl tetrachloroterephthalate or DCPA, a herbicide) contamination in the unsaturated and saturated zones for a 150 km² site

  10. RESEARCH ON GROUND-WATER CONTAMINATED BY DEPOSITS OF SOLID WASTE

    Microsoft Academic Search

    Arthur GOLWER; Georg MATTHESS

    SUMMARY Field investigations at large waste sites of industrial and municipal origin allow to determine the rules of behaviour of contaminants in the ground more completely than laboratory experiments and small scale field investigations. The difference of the chemical and bacteriological quality of groundwater before and after passing the waste site gives the amount of the contamination. The changes of

  11. Using models to simulate the movement of contaminants through groundwater flow systems

    Microsoft Academic Search

    Mary P. Anderson; John A. Cherry

    1979-01-01

    Prediction of the movement of contaminants in groundwater systems through the use of models has been given increased emphasis in recent years because of the growing trend toward subsurface disposal of wastes. Prediction is especially critical when nuclear wastes are involved. Contaminant transport models which include the effects of dispersion have been applied to several field situations. However, factors that

  12. Surface altered zeolites as permeable barriers for in situ treatment of contaminated groundwater

    SciTech Connect

    NONE

    1996-11-01

    The authors characterized surfactant-modified zeolite (SMZ) for its ability to sorb organic and inorganic contaminants from water. The ultimate objective is to use SMZ as a permeable barrier to prevent migration of contaminants in groundwater. This report summarizes results under Phase 1 of a three-phase project leading to a full-scale field demonstration of SMZ permeable- barrier technology.

  13. Groundwater arsenic contamination affecting different geologic domains in India - a review: influence of geological setting, fluvial geomorphology and Quaternary stratigraphy

    SciTech Connect

    Acharyya, S.K.; Shah, B.A. [Jadavpur University, Calcutta (India). Dept. of Geological Science

    2007-10-15

    Arsenic contamination in groundwater is pervasive within lowland organic-rich Bengal Delta and narrow entrenched channels in the Middle Ganga floodplains. Local areas of Damodar fan-delta and isolated areas within the Dongargarh Proterozoic rift-zone in central India are also contaminated. In this rift-zone, arsenic is enriched in felsic magmatic rocks and weathered rocks and soils from local areas are enriched further in arsenic and iron. Late Quaternary stratigraphy, geomorphology and sedimentation have influenced groundwater arsenic contamination in alluvium that aggraded during the Holocene sea-level rise. No specific source of arsenic could be identified, although Himalaya is the main provenance for the Ganga floodplain and the Bengal Delta. Gondwana coal seams and other Peninsular Indian rocks might be sources for arsenic in the Damodar fan-delta. As-bearing pyrite or any As-mineral is nearly absent in the aquifer sediments. Arsenic mainly occurs adsorbed on hydrated-iron-oxide (HFO), which coat sediment grains and minerals. Arsenic and iron are released to groundwater by bio-mediated reductive dissolution of HFO with corresponding oxidation of organic matter.

  14. Evaluation of the sources of contamination in the suburban area of Koropi-Markopoulo, Athens, Greece.

    PubMed

    Kaitantzian, Agavni; Kelepertzis, Efstratios; Kelepertsis, Akindynos

    2013-07-01

    Heavy metal concentrations were monitored in agricultural soils and irrigation groundwaters of Koropi-Markopoulo area, a representative agricultural suburb in Athens, Greece, aiming at the identification of the sources of contaminants. Multivariate analyses of geochemical data demonstrated that agricultural practices and industrial activities considerably affected the quality of both environmental compartments. The levels of Ni, Cr, Co, Mn and Fe in agricultural soils were associated with geological parent materials whereas Pb, Zn and Cu mainly originated from anthropic activities. Referring to groundwaters, individual major anions and cations (K?, Na?, Ca²?, Mg²?, NO??, SO?²?, Cl?) were influenced by various natural and anthropogenic factors whereas Ni, Cr, Cu and Zn were controlled by industrial and agronomic activities. The identification of the sources of contaminants in soil and groundwater environments is a valuable basis for encouraging mitigation strategies preventing further quality degradation. PMID:23728354

  15. Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

    SciTech Connect

    K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

    2004-03-01

    The purpose of this work is to characterize groundwater flow and contaminant transport at the Shoal underground nuclear test through numerical modeling using site-specific hydrologic data. The ultimate objective is the development of a contaminant boundary, a model-predicted perimeter defining the extent of radionuclide-contaminated groundwater from the underground test throughout 1,000 years at a prescribed level of confidence. This boundary will be developed using the numerical models described here, after they are approved for that purpose by DOE and NDEP.

  16. Sources and impact of sulphate on groundwaters of Triassic carbonate aquifers, Upper Silesia, Poland

    NASA Astrophysics Data System (ADS)

    Samborska, Katarzyna; Halas, Stanislaw; Bottrell, Simon H.

    2013-04-01

    SummaryGroundwater within the unconfined or semi-confined parts of Triassic carbonate aquifers in Upper Silesia (Poland) contains high concentrations of sulphate (up to 290 mg/L), sometimes in excess of drinking water limits (>250 mg/L). To assess the influence of different possible sulphate sources, isotopic analyses of S and O were performed on groundwater sulphate and potential sulphate sources and combined with literature data. Three dominant sources of sulphate were delineated, based on the geological and literature study and supported by the mixing relations between inverse concentration of sulphate and its isotopic compositions. These sources are: (i) sulphate from rainfall; (ii) weathering of sulphide minerals in ore deposits in the aquifer-forming carbonate rocks; (iii) dissolution of sulphate evaporites in the Triassic sequence. Fortunately these three sources have distinctive S and O isotope compositions and thus their contributions to the total dissolved sulphate could be estimated. The application of linear mixing models for three sources in the dual isotope system allowed the impact of the three different sulphate sources on particular parts of the aquifers to be calculated. The average isotopic composition of sulphate in abstracted groundwater indicates that the most important source of sulphate is sulphide weathering, contributing about 50% of total sulphate. The second most significant source of sulphate input is rainfall and it is characterised by a mean contribution of 30%. Application of Monte Carlo analysis that incorporates the full variability in distributions of isotopic compositions for the three sources and all mixing fractions between them gave the most probable ranges of the dissolved in groundwater sulphate. This analysis indicated that the proportion of sulphate derived by sulphide oxidation is comparable with the estimations based on linear models. This study has shown that the water quality of these important groundwater resources is under threat from both natural sources, i.e. metal sulphide oxidation and gypsum dissolution. Analysis of the mathematical models analysis shows that the first process is the predominant source of sulphate in groundwater. However, the highest concentrations of dissolved sulphate are positively correlated with the increasing proportion of sulphate derived from gypsum dissolution. Moreover, one should keep in mind that natural processes might be anthropogenically accelerated due to variable water demands and groundwater abstraction. Eventually, the statistically second-order source of sulphate - rainfall might contain surface-derived contaminants, and its contribution to the total load of sulphate might indirectly indicate the vulnerability of aquifers for the pollution.

  17. Tracing nitrate pollution sources and transformation in surface- and ground-waters using environmental isotopes.

    PubMed

    Zhang, Yan; Li, Fadong; Zhang, Qiuying; Li, Jing; Liu, Qiang

    2014-08-15

    Water pollution in the form of nitrate nitrogen (NO3(-)-N) contamination is a major concern in most agricultural areas in the world. Concentrations and nitrogen and oxygen isotopic compositions of nitrate, as well as oxygen and deuterium isotopic compositions of surface and groundwater from a typical irrigated region in the North China Plain (NCP) collected from May to October in 2012 were analyzed to examine the major nitrate sources and transformations. Concentrations of NO3(-)-N ranged from 0.2 to 29.6 mg/L (mean of 11.2 mg/L) in surface water, and from 0.1 to 19.4 mg/L (mean of 2.8 mg/L) in groundwater. Approximately 46.7% of the surface water samples and 10% of the groundwater samples exceeded the World Health Organization (WHO) drinking water standard for NO3(-)-N. Surface water samples that exceeded the standard were collected mainly in the dry season (May and October), while groundwater samples that exceeded the standard were collected in the wet season (June). Overall, the highest nitrate levels were observed in surface water in May and in groundwater in June, indicating that fertilizer application, precipitation, and irrigation strongly influence the NO3(-)-N concentrations. Analyses of isotopic compositions suggest that the main sources of nitrate are nitrification of fertilizer and sewage in surface water, in contrast, mineralization of soil organic N and sewage is the groundwater sources during the dry season. When fertilizers are applied, nitrate will be transported by precipitation through the soil layers to the groundwater in the wet season (June). Denitrification only occurred in surface water in the wet season. Attempts should be made to minimize overuse of nitrogen fertilizers and to improve nitrogen use efficiency in irrigated agricultural regions. PMID:24858219

  18. Atacama perchlorate as an agricultural contaminant in groundwater: Isotopic and chronologic evidence from Long Island, New York

    USGS Publications Warehouse

    Böhlke, J.K.; Hatzinger, P.B.; Sturchio, N.C.; Gu, B.; Abbene, I.; Mroczkowski, S.J.

    2009-01-01

    Perchlorate (ClO4-) is a common groundwater constituent with both synthetic and natural sources. A potentially important source of ClO4- is past agricultural application of ClO4--bearing natural NO3- fertilizer imported from the Atacama Desert, Chile, but evidence for this hasbeenlargely circumstantial. Here we report ClO4- stable isotope data (??37Cl, ??18O, and ??17O), along with other supporting chemical and isotopic environmental tracer data, to document groundwater ClO4- contamination sources and history in parts of Long Island, New York. Sampled groundwaters were oxic and ClO4- apparently was not affected by biodegradation within the aquifers. Synthetic ClO4- was indicated by the isotopic method in groundwater near a fireworks disposal site at a former missile base. Atacama ClO4- was indicated in agricultural and urbanizing areas in groundwaters with apparent ages >20 years. In an agricultural area, ClO4- concentrations and ClO4-/NO3- ratios increased withgroundwaterage, possiblybecauseof decreasing application rates of Atacama NO3- fertilizers and/or decreasing ClO4- concentrations in Atacama NO 3- fertilizers in recent years. Because ClO 4-/NO3- ratios of Atacama NO 3- fertilizers imported in the past (???2 ?? 10-3 mol mol-1) were much higher than the ClO 4-/NO3- ratio of recommended drinking-water limits (7 ?? 10-5 mol mol-1 in New York), ClO4- could exceed drinkingwater limits even where NO3- does not, and where Atacama NO3- was only a minor source of N. Groundwater ClO4- with distinctive isotopic composition was a sensitive indicator of past Atacama NO3- fertilizer use on Long Island and may be common in other areas that received NO3- fertilizers from the late 19th century through the 20th century. ?? 2009 American Chemical Society.

  19. K{sub d} in screening-level ground-water contaminant-transport model

    Microsoft Academic Search

    M. L. Goyette; B. A. G. Lewis

    1995-01-01

    This paper describes the use of system-specific and literature values for the distribution coefficient (K{sub d}) in a screening-level ground-water contaminant-transport model. A comparison of observed contaminant transport (Cd{sup 2+}) in a laboratory soil column with predicted contaminant transport using a computer model is described and discussed. The results indicate that measured K{sub d} values and K{sub d} values taken

  20. QUALITY ASSURANCE IN COMPUTER SIMULATIONS OF GROUNDWATER CONTAMINATION

    EPA Science Inventory

    In the development of policies and regulations for groundwater protection, in permitting, and in planning monitoring and remedial actions, the role of mathematical models is growing rapidly. Because water-resource management decisions should be based on technically and scientific...

  1. Chemistry and sulfur isotope investigation of industrial wastewater contamination into groundwater aquifers, Piteå County, N. Sweden

    Microsoft Academic Search

    Peter Torssander; Carl-Magnus Mörth; Risto Kumpulainen

    2006-01-01

    The possible contamination of a groundwater system with industrial wastewater originating from a paper mill factory has been investigated in Piteå, N. Sweden. Six samples were collected from the wastewater in the waste dump and twelve samples from the adjacent groundwater were analyzed for chemistry and sulfur isotopes. The industrial wastewater is a saline water consisting mainly of Na–HCO3–SO4, having

  2. Shallow-Probe Soil-Gas Sampling for Indication of Ground-Water Contamination by Chloroform

    Microsoft Academic Search

    Henry B. Kerfoot

    1987-01-01

    Soil-gas sampling and analysis for indication of ground-water contamination by chloroform was field tested. The field testing included evaluation of: The repeatability of results, the correlation of results of soil-gas analyses with ground-water concentrations, the differences in results among closely spaced samples and the depth profile of chloroform concentrations in soil-gas samples. The sampling probe gave good repeatability, although leakage

  3. Ultrasonic process for remediation of organics-contaminated groundwater/wastewater

    SciTech Connect

    Wu, J.M.; Peters, R.W.

    1995-07-01

    A technology is being developed that employs ultrasonic-wave energy for remediation of groundwater/wastewater contaminated with volatile organic compounds such as carbon tetrachloride (CCl{sub 4}) and trichloroethylene (TCE). This paper presents the updated results of a laboratory investigation of ultrasonic groundwater remediation using synthetic groundwaters prepared with laboratory deionized water. Key process parameters investigated included steady-state temperature, contaminant concentration, solution pH, sonication time, and intensity of the applied ultrasonics-wave energy. High destruction efficiencies of the target contaminants were achieved, and the sonication time required for a given degree of destruction decreased with increasing intensity of the applied ultrasonic energy. The sonication time can be further reduced by adding a chemical oxidant such as hydrogen peroxide.

  4. Chromium isotope variation along a contaminated groundwater plume: a coupled Cr(VI)- reduction, advective mixing perspective

    NASA Astrophysics Data System (ADS)

    Bullen, T.; Izbicki, J.

    2007-12-01

    Chromium (Cr) is a common contaminant in groundwater, used in electroplating, leather tanning, wood preservation, and as an anti-corrosion agent. Cr occurs in two oxidation states in groundwater: Cr(VI) is highly soluble and mobile, and is a carcinogen; Cr(III) is generally insoluble, immobile and less toxic than Cr(VI). Reduction of Cr(VI) to Cr(III) is thus a central issue in approaches to Cr(VI) contaminant remediation in aquifers. Aqueous Cr(VI) occurs mainly as the chromate (CrO22-) and bichromate (HCrO2-) oxyanions, while Cr(III) is mainly "hexaquo" Cr(H2O)63+. Cr has four naturally-occurring stable isotopes: 50Cr, 52Cr, 53Cr and 54Cr. When Cr(VI) is reduced to Cr(III), the strong Cr-O bond must be broken, resulting in isotopic selection. Ellis et al. (2002) demonstrated that for reduction of Cr(VI) on magnetite and in natural sediment slurries, the change of isotopic composition of the remnant Cr(VI) pool was described by a Rayleigh fractionation model having fractionation factor ?Cr(VI)-Cr(III) = 3.4‰. We attempted to use Cr isotopes as a monitor of Cr(VI) reduction at a field site in Hinkley, California (USA) where groundwater contaminated with Cr(VI) has been under assessment for remediation. Groundwater containing up to 5 ppm Cr(VI) has migrated down-gradient from the contamination source through the fluvial to alluvial sediments to form a well-defined plume. Uncontaminated groundwater in the aquifer immediately adjacent to the plume has naturally-occurring Cr(VI) of 4 ppb or less (CH2M-Hill). In early 2006, colleagues from CH2M-Hill collected 17 samples of groundwater from within and adjacent to the plume. On a plot of ?53Cr vs. log Cr(VI), the data array is strikingly linear and differs markedly from the trend predicted for reduction of Cr(VI) in the contaminated water. There appear to be two groups of data: four samples with ?53Cr >+2‰ and Cr(VI) <4 ppb, and 13 samples with ?53Cr <+2‰ and Cr(VI) >15 ppb. Simple mixing lines between the groundwater samples having <4 ppb Cr(VI), taken to be representative of regional groundwater, and the contaminated water do not pass through the remainder of the data, discounting a simple advective mixing scenario. We hypothesize a more likely scenario that involves both Cr(VI) reduction and advective mixing. As the plume initially expands downgradient, Cr(VI) in water at the leading edge encounters reductant in the aquifer resulting in limited Cr(VI) reduction. As a result of reduction, ?53Cr of Cr(VI) remaining in solution at the leading edge increases along the "reduction" trend from 0 to ~+2‰. Inevitable mixing of this water at the leading edge with regional groundwater results in a suitable mixing end-member to combine with Cr(VI) within the plume in order to explain the bulk of the remaining data. Neither Cr(VI) reduction nor advective mixing of plume and regional groundwaters can explain the data on their own, implying an interplay of at least these two processes during plume evolution. Ellis, A.S., Johnson, T.M. and Bullen, T.D. 2002, Science, 295, 2060-2062.

  5. Evaluating Chemical Tracers as Indicators of Nitrate-Nitrogen Sources in Groundwater

    NASA Astrophysics Data System (ADS)

    Nitka, A.; DeVita, W.; McGinley, P.

    2014-12-01

    Groundwater nitrate-N concentrations greater than 3 mg/L usually indicate contamination from either agriculture or wastewater disposal. The objective of this study was to use chemical indicators to reliably determine sources of nitrate contamination in private wells. We developed an analytical method for a suite of human waste indicators. The selection of chemical tracers was based on their likely occurrence and mobility in groundwater. The suite included artificial sweeteners, pharmaceuticals and personal care products. Pesticide metabolites were used to identify contamination due to agricultural practices. A densely populated suburban area with adjacent agricultural land was selected. Eighteen private water supply wells and six monitoring wells were analyzed for nitrate-N and contaminant indicators. All of the wells with nitrate concentrations greater than 3 mg/L had at least one chemical indicator. Of these, 90% had two or more human waste contaminants, 40% had pesticide metabolites, and 30% had both. Of the wells with nitrate greater than 10 mg/L, 80% had two or more human waste indicators, 70% had pesticide metabolites, and 50% had both. The results of this research will help direct land management decisions and selection of appropriate water treatment options.

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

    PubMed

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

    2003-01-01

    The only natural freshwater resource of Kuwait occurs as lenses floating on the saline groundwater in the northern part of the country, near to the oil fields. Rainwater is the only means of recharge of this limited groundwater resource. This groundwater is used as bottled drinking water and the fresh groundwater aquifer is considered as a strategic drinking water reserve for Kuwait. As a result of the 1991 Gulf War, the upper soil layer has been widely contaminated with crude oil and crude oil combustion products, which are potential pollutants likely affecting the groundwater resources. Significant efforts have been made to assess this pollution. These included: (a) a soil survey for assessing the soil contamination, and (b) leaching experiments to characterise the mobilization of the soil-associated pollutants. Fluorescence measurement techniques were used during field surveys as well as for laboratory testing. In addition, determination of the total extractable matter (TEM), total petroleum hydrocarbons (TPH), and GC/MS measurement of polyaromatic hydrocarbons (PAHs) were performed for the assessments. The laser induced fluorescence (LIF) measurement, having good correlation with the other laboratory measurements, was proved to provide necessary information for the assessment of the oil-contamination level in the desert soil. The subsequent leaching test with water demonstrated the mobilization of the fluorescing compounds (e.g. PAHs), and the alteration in the leaching characteristics of the contamination during the long-term environmental weathering of the oil. PMID:12793688

  7. Groundwater arsenic contamination on the Ganges Delta: biogeochemistry, hydrology, human perturbations, and human suffering on a large scale

    Microsoft Academic Search

    Charles F. Harvey; Christopher H. Swartz; Abu Bohran M. Badruzzaman; Nicole Keon-Blute; Winston Yu; M. Ashraf Ali; Jenny Jay; Roger Beckie; Volker Niedan; Daniel Brabander; Peter M. Oates; Khandaker N. Ashfaque; Shafiqul Islam; Harold F. Hemond; M. Feroze Ahmed

    2005-01-01

    Over the last several decades, much of population of Bangladesh and West Bengal switched their water supply from surface water to groundwater. Tragically, much of the region's groundwater is dangerously contaminated by arsenic, and consumption of this water has already created severe health effects. Here we consider how groundwater flow may affect arsenic biogeochemistry and we compare the vertical patterns

  8. Modeling to Support Groundwater Contaminant Boundaries for the Shoal Underground Nuclear Test

    SciTech Connect

    K. Pohlmann; G. Pohll; J. Chapman; A. Hassan; R. Carroll; C. Shirley

    2004-03-01

    Groundwater flow and radionuclide transport at the Shoal underground nuclear test are characterized using three-dimensional numerical models, based on site-specific hydrologic data. The objective of this modeling is to provide the flow and transport models needed to develop a contaminant boundary defining the extent of radionuclide-contaminated groundwater at the site throughout 1,000 years at a prescribed level of confidence. This boundary will then be used to manage the Project Shoal Area for the protection of the public and the environment.

  9. In-situ remediation system and method for contaminated groundwater

    DOEpatents

    Corey, John C. (Aiken, SC); Looney, Brian B. (Aiken, SC); Kaback, Dawn S. (Aiken, SC)

    1989-01-01

    A system for removing volatile contaminants from a subsurface plume of contamination comprising two sets of wells, a well for injecting a fluid into a saturated zone on one side of the plume and an extracting well for collecting the fluid together with volatilized contaminants from the plume on the other side of the plume. The fluid enables the volatile contaminants to be volatilized and carried therewith through the ground to the extracting well. Injecting and extracting wells are preferably horizontal wells positioned below the plume in the saturated zone and above the plume in the vadose zone, respectively. The fluid may be air or other gas or a gas and liquid mixture depending on the type of contaminant to be removed and may be preheated to facilitate volatilization. Treatment of the volatilized contamination may be by filtration, incineration, atmospheric dispersion or the like.

  10. GIS techniques applied to non-point contamination predictions in Illinois groundwater

    SciTech Connect

    Schock, S.C. (Environmental Protection Agency, Cincinnati, OH (United States)); Keefer, D.; Mehnert, E. (Illinois State Geological Survey, Champaign, IL (United States)); Ray, C. (Illinois State Water Survey, Champaign, IL (United States))

    1994-03-01

    The Illinois State Water Survey and the Illinois State Geological Survey, parts of the Illinois Department of Energy and Natural Resources, as part of the mandates of the Illinois Groundwater Protection Act, undertook a project to determine the potential for vulnerability to contamination by agricultural chemicals in private domestic wells throughout the State. GIS techniques were heavily relied upon to establish four categories of potential vulnerability to such contamination. Information from several sources, Federal, State and Local, were used to develop the coverages which were finally overlain to create the map. Criteria for the evaluation of the potential for vulnerability included location with respect to agricultural chemical application, storage, and preparation, urban vs. rural setting land use, depth below surface to aquifer materials, and soils information. Illinois has more in-depth information on these kinds of information than many of the States, and still there were problems in accumulating the needed data. These included, lack of availability, poor documentation of data collection and storage protocols, and the lack of adequate detail within datasets. Supplementation of information before the application of GIS techniques was needed.

  11. 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

    Preliminary investigations of the geology, groundwater hydrology , and soil and groundwater chemistry at sites in Pine and St. Louis Counties, Minnesota, have shown that contamination associated with pesticides buried at the sites is not widespread or highly concentrated. None of the pesticides sampled for in soil and in groundwater at the sites exceeded Minnesota soil and drinking water standards. About 1,500 pounds of lead arsenate were buried at the site in St. Louis County. Nearly 10,000 pounds of lead arsenate, as well as smaller quantities of organic pesticides (such as chlorpropham, DDT, endrin, and aldrin), lime sulfur, and magnesium carbonate were buried at the Pine County site. These chemicals were buried in shallow trenches at the sites during the early 1970's. The first wells drilled at each site were located to establish the direction of horizontal groundwater flow in each area. Groundwater flows to the northeast at the St. Louis County site and to the southeast at the Pine County site. Depths to the water table are about 30 ft at the Pine County site and about 25 ft at the St. Louis County site. In addition, groundwater is perched seasonally at about 5 ft below land surface in the immediate vicinity fo the burial site in Pine County. After the direction of flow was determined, additional wells were drilled down-gradient from the disposal areas at both sites to determine whether contaminations were migrating with groundwater away from the sites. 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. (Author 's abstract)

  12. Inorganic contaminants from diffuse pollution in shallow groundwater of the Campanian Plain (Southern Italy). Implications for geochemical survey.

    PubMed

    Cuoco, E; Darrah, T H; Buono, G; Verrengia, G; De Francesco, S; Eymold, W K; Tedesco, D

    2015-02-01

    The Campanian Plain (CP) shallow aquifer (Southern Italy) represents a natural laboratory to validate geochemical methods for differentiating diffuse anthropogenic pollution from natural water-rock interaction processes. The CP is an appropriate study area because of numerous potential anthropogenic pollution vectors including agriculture, animal husbandry, septic/drainage sewage systems, and industry. In order to evaluate the potential for geochemical methods to differentiate various contamination vectors, 538 groundwater wells from the shallow aquifer in Campanian Plain (CP) were sampled. The dataset includes both major and trace elements. Natural water-rock interactions, which primarily depend on local lithology, control the majority of geochemical parameters, including most of the major and trace elements. Using prospective statistical methods in combination with the traditional geochemical techniques, we determined the chemical variables that are enriched by anthropogenic contamination (i.e. NO3, SO4 and U) by using NO3 as the diagnostic variable for detecting polluted groundwater. Synthetic agricultural fertilizers are responsible for the majority of SO4 and U pollution throughout the CP area. Both SO4 and U are present in the groundmass of synthetic fertilizers; the uranium concentration is specifically applicable as a tracer for non-point source agricultural fertilizer contamination. The recognition of non-geological (anthropogenic) inputs of these elements has to be considered in the geochemical investigations of contaminated aquifers. PMID:25638062

  13. Land-use change and costs to rural households: a case study in groundwater nitrate contamination

    NASA Astrophysics Data System (ADS)

    Keeler, Bonnie L.; Polasky, Stephen

    2014-07-01

    Loss of grassland from conversion to agriculture threatens water quality and other valuable ecosystem services. Here we estimate how land-use change affects the probability of groundwater contamination by nitrate in private drinking water wells. We find that conversion of grassland to agriculture from 2007 to 2012 in Southeastern Minnesota is expected to increase the future number of wells exceeding 10 ppm nitrate-nitrogen by 45% (from 888 to 1292 wells). We link outputs of the groundwater well contamination model to cost estimates for well remediation, well replacement, and avoidance behaviors to estimate the potential economic value lost due to nitrate contamination from observed land-use change. We estimate 0.7-12 million in costs (present values over a 20 year horizon) to address the increased risk of nitrate contamination of private wells. Our study demonstrates how biophysical models and economic valuation can be integrated to estimate the welfare consequences of land-use change.

  14. Herbicide contamination of surficial groundwater in Northern Italy

    Microsoft Academic Search

    Licia Guzzella; Fiorenzo Pozzoni; Giuseppe Giuliano

    2006-01-01

    Data on herbicide pollution in groundwater are rather scarce; monitoring data are based on single investigation, focussing on limited area and on few compounds of interest. The large number of approved active ingredients (approximately 600 chemicals) makes difficult to obtain an accurate and actual information on herbicide application in different countries, even if herbicides are the second most important class

  15. Heavy metal contamination from geothermal sources.

    PubMed Central

    Sabadell, J E; Axtmann, R C

    1975-01-01

    Liquid-dominated hydrothermal reservoirs, which contain saline fluids at high temperatures and pressures, have a significant potential for contamination of the environment by heavy metals. The design of the power conversion cycle in a liquid-dominated geothermal plant is a key factor in determining the impact of the installation. Reinjection of the fluid into the reservoir minimizes heavy metal effluents but is routinely practiced at few installations. Binary power cycles with reinjection would provide even cleaner systems but are not yet ready for commercial application. Vapor-dominated systems, which contain superheated steam, have less potential for contamination but are relatively uncommon. Field data on heavy metal effluents from geothermal plants are sparse and confounded by contributions from "natural" sources such as geysers and hot springs which often exist nearby. Insofar as geothermal power supplies are destined to multiply, much work is required on their environmental effects including those caused by heavy metals. PMID:1227849

  16. MONITORED NATURAL ATTENUATION FOR INORGANIC CONTAMINANT REMEDIATION IN GROUNDWATER

    EPA Science Inventory

    Monitored natural attenuation (MNA) has been applied as a knowledge-based remediation technology for organic contaminants in ground water. Development of a site-specific assessment of biotic and abiotic processes that lead to organic contaminant degradation provides the technica...

  17. Remediation of arsenic-contaminated soils and groundwaters

    DOEpatents

    Peters, Robert W. (Naperville, IL); Frank, James R. (Glen Ellyn, IL); Feng, Xiandong (West Richland, WA)

    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.

  18. A multi-level assessment methodology for determining the potential for groundwater contamination by pesticides

    Microsoft Academic Search

    A. S. Crowe; W. G. Booty

    1995-01-01

    A multi-level pesticide assessment methodology has been developed to permit regulatory personnel to undertake a variety of assessments on the potential for pesticide used in agricultural areas to contaminate the groundwater regime at an increasingly detailed geographical scale of investigation. A multi-level approach accounts for a variety of assessment objectives and detail required in the assessment, the restrictions on the

  19. A BIOTIC CONTROL PERSPECTIVE ON NITRATE CONTAMINATION OF GROUNDWATER FROM AGRICULTURAL PRODUCTION

    Microsoft Academic Search

    Jon D. Erickson; Felix Schlapfer

    2001-01-01

    Agronomists consider the continuity and nutrient capturing properties of cover crops as important determinants of nutrient cycling in agricultural systems. Managing for these biotic control functions can help limit nutrient loss and groundwater contamination between main crop harvests. This simulation study highlights the potential role of cover crop management in a welfare economics framework. The objective is to find the

  20. 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 ...

  1. Remediation of Petroleum-Contaminated Groundwater Using High Carbon Content Fly Ash

    E-print Network

    Aydilek, Ahmet

    to coal-burning power plants. Such fly ashes have no value as a concrete additive and require high land in the utilization of recycled materials for remediation of contaminated groundwater as a part of sorptive barrier investigations. Recycled materials, such as tire chips (Kim et al 1997) and foundry sand (Lee et al. 2004) have

  2. Ammonium transport and reaction in contaminated groundwater: Application of isotope tracers and isotope fractionation studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ammonium (NH4 +) is a major constituent of many contaminated groundwaters, but its movement through aquifers is complex and poorly documented. In this study, processes affecting NH4 + movement in a treated wastewater plume were studied by a combination of techniques including large-scale monitoring...

  3. OASIS: A GEOGRAPHICAL DECISION SUPPORT SYSTEM FOR GROUND-WATER CONTAMINANT MODELING

    EPA Science Inventory

    Three new software technologies were applied to develop an efficient and easy to use decision support system for ground-water contaminant modeling. Graphical interfaces create a more intuitive and effective form of communication with the computer compared to text-based interfaces...

  4. EVALUATION OF SULFATE-REDUCING BACTERIA TO PRECIPITATE MERCURY FROM CONTAMINATED GROUNDWATER

    EPA Science Inventory

    Several regions in the Republic of Kazakhstan are contaminated with mercury as a result of releases from industrial plants. Operations at an old chemical plant, "Khimprom", which produced chlorine and alkali in the 1970s - 1990s, resulted in significant pollution of groundwater ...

  5. Testing of a benchscale Reverse Osmosis/Coupled Transport system for treating contaminated groundwater

    SciTech Connect

    Hodgson, K.M.; Lunsford, T.R.; Panjabi, G.

    1994-01-01

    The Reverse Osmosis/Coupled Transport process is a innovative means of removing radionuclides from contaminated groundwater at the Hanford Site. Specifically, groundwater in the 200 West Area of the Hanford Site has been contaminated with uranium, technetium, and nitrate. Investigations are proceeding to determine the most cost effective method to remove these contaminants. The process described in this paper combines three different membrane technologies (reverse osmosis, coupled transport, and nanofiltration to purify the groundwater while extracting and concentrating uranium, technetium, and nitrate into separate solutions. This separation allows for the future use of the radionuclides, if needed, and reduces the amount of waste that will need to be disposed of. This process has the potential to concentrate the contaminants into solutions with volumes in a ratio of 1/10,000 of the feed volume. This compares to traditional volume reductions of 10 to 100 for ion exchange and stand-alone reverse osmosis. The successful demonstration of this technology could result in significant savings in the overall cost of decontaminating the groundwater.

  6. On the performance of computational methods for the assessment of risk from ground-water contamination

    SciTech Connect

    Hamed, M.M.; Bedient, P.B. [Rice Univ., Houston, TX (United States)

    1997-07-01

    The effect of parameter uncertainty and overly conservative measures on risk assessment has been addressed in numerous researches. Most of the work conducted to date is based on the use of the classic Monte Carlo simulation method (MCS) as a probabilistic modeling tool. Although the MCS is robust and asymptotically convergent, it lacks computational efficiency when the simulated probability is small. Furthermore, the sensitivity information can only be obtained with additional computational effort. First- and second-order reliability methods (FORM and SORM) have been developed in the structural analysis field and have been recently applied to ground-water contaminant transport and remediation problems. In this work, the authors extend the application of the reliability methods to the probabilistic assessment of cancer risk due to ground-water contamination. Results of the reliability methods compared well with a published case study of PCE contamination of a ground-water supply in California. The target risk level is extended over a larger range, and the sensitivity of the probability of failure to the relevant random variables is analyzed. The application of the methods to another case study, cancer risk due to the ingestion of benzene contaminated water, further illustrates a systematic way of directly accounting for the intrinsic uncertainty of the transport and fate model parameters involved in the risk assessment procedure. The probability of exceeding the target risk level in this case was found to be most sensitive to the uncertainty in the parameters describing the ground-water transport process.

  7. In Situ Bioremediation of Perchlorate-Contaminated Groundwater using a Multi-Objective Parallel Evolutionary Algorithm

    E-print Network

    Coello, Carlos A. Coello

    In Situ Bioremediation of Perchlorate-Contaminated Groundwater using a Multi-Objective Parallel technology like in situ bioremediation, system optimization is not straightforward. In this study, a general). One such technology, in situ bioremediation, makes use of indigenous microorganisms. Fo

  8. Potential Radiological Doses From Groundwater Contaminated By The Saltstone Disposal Facility

    Microsoft Academic Search

    2005-01-01

    Assessments of radiological dose from usage of groundwater potentially contaminated by the Saltstone Disposal Facility (Z-Area) were made for a hypothetical future resident farmer. These assessments were made using the routine aqueous release model LADTAP XL (C), which is the model used for demonstrating liquid pathway dose compliance at SRS. The dose factors used in LADTAP XL (C) are those

  9. Neuropathy in Arsenic Toxicity from Groundwater Arsenic Contamination in West Bengal, India

    Microsoft Academic Search

    Subhash Chandra Mukherjee; Mohammad Mahmudur Rahman; Uttam Kumar Chowdhury; Mrinal Kumar Sengupta; Dilip Lodh; Chitta Ranjan Chanda; Kshitish Chandra Saha; Dipankar Chakraborti

    2003-01-01

    Large number of people from 9 out of 18 districts of West Bengal, India are endemically exposed to arsenic contaminated groundwater due to drinking of tubewell water containing arsenic level above World Health Organization's maximum permissible limit of 50 µg\\/L. From our ongoing studies on neurological involvement in patients of arsenicosis from different districts of West Bengal, we report our findings

  10. Geological and geochemical examination of arsenic contamination in groundwater in the Holocene Terai Basin, Nepal

    Microsoft Academic Search

    Jaya K. Gurung; Hiroaki Ishiga; Mohan S. Khadka

    2005-01-01

    Geological and geochemical study has been carried out to investigate arsenic contamination in groundwater in Nawalparasi, the western Terai district of Nepal. The work carried out includes analyses of core sediments, provenance study by rare earth elements analyses, 14C dating, and water analyses. Results showed that distribution of the major and trace elements are not homogeneous in different grain size

  11. SURFACE-ALTERED ZEOLITES AS PERMEABLE BARRIERS FOR IN SITU TREATMENT OF CONTAMINATED GROUNDWATER

    SciTech Connect

    Robert S. Bowman; Zhaohui Li; Stephen J. Roy; Todd Burt; Timothy L. Johnson; Richard L. Johnson

    1999-08-30

    The overall objective of this effort is to develop and test a zeolite-based permeable barrier system for containing and remediating contaminated groundwater. The projected product is an engineered and tested permeable barrier system that can be adopted by the commercial sector.

  12. Design of cost-effectiv e programs for monitoring ground-water contamination

    Microsoft Academic Search

    DENNIS B. MCLAUGHLIN; WENDY D. GRAHAM

    1986-01-01

    Ground-water contamination often is first detected from water samples drawn from a few scattered wells. In most cases, additional wells must be drilled and more samples collected before the extent and severity of the problem can be determined with acceptable accuracy. Since sampling programs can be very expensive, monitoring networks should be carefully designed so that the maximum amount of

  13. Appendix H: Past and Current Groundwater Flow and Contamination beneath Shell Tank Waste Management Areas

    SciTech Connect

    Horton, Duane G.

    2008-01-17

    This is being prepared as an appendix for CH2M HILL Hanford Group, Inc. and is part of PNNL support of the RCRA Facility Investigation Report. The document contains a detailed description of groundwater flow and contamination under the Central Plateau, emphasizing the areas around the tank farms.

  14. Past and Current Groundwater Flow and Contaminant Distribution at Single-Shell Tank Waste Management Areas

    SciTech Connect

    Horton, Duane G.

    2008-01-17

    This will be part of a CH2M HILL document. It summarizes important finidings from historic and recent groundwater investigations of the uppermost aquifer beneath the 200 East and 200 West Areas. The document also summarizes ongoing work to further characterize the unconfined aquifer and contaminants in that aquifer.

  15. Assessment of Groundwater Vulnerability to Contamination Using Capture Zone Delineation in Shenzhen City, China

    Microsoft Academic Search

    Chiha Aida; Aiguo Zhou; Jianwei Zhou; Shao-Gang Dong

    2009-01-01

    As a result of the large risk associated with the contamination of aquifers, it becomes imperative to protect groundwater supply areas. One of the practical methods that is projected for the protection of aquifers is to zone a boundary around current production in order to control hazardous industrial practices close to the wells supply. Nanping Highway is proposed to be

  16. Grand challenge problems in environmental modeling and remediation: groundwater contaminant transport

    SciTech Connect

    Todd Arbogast; Steve Bryant; Clint N. Dawson; Mary F. Wheeler

    1998-08-31

    This report describes briefly the work of the Center for Subsurface Modeling (CSM) of the University of Texas at Austin (and Rice University prior to September 1995) on the Partnership in Computational Sciences Consortium (PICS) project entitled Grand Challenge Problems in Environmental Modeling and Remediation: Groundwater Contaminant Transport.

  17. Occurrence and suitability of pharmaceuticals and personal care products as molecular markers for raw wastewater contamination in surface water and groundwater.

    PubMed

    Tran, Ngoc Han; Li, Jinhua; Hu, Jiangyong; Ong, Say Leong

    2014-03-01

    This study aimed to provide the first and comprehensive data on the occurrence of 17 target pharmaceuticals and personal care products (PPCPs) in urban water environment in Singapore. Meanwhile, this study also verified the suitability of these PPCPs as specific markers of raw wastewater contamination in receiving water bodies in highly urbanized areas where both surface water and groundwater are not impacted by the discharge of treated wastewater effluents. Analytical results of wastewater showed that among 17 target PPCPs examined, only 5 PPCPs were detected in 100 % of raw wastewater samples, including acetaminophen (ACT), carbamazepine (CBZ), caffeine (CF), diethyltoluamide (DEET), and salicylic acid (SA). Similarly, these PPCPs were found in most surface water and groundwater. Interestingly, the three PPCPs (ACT, CBZ, and SA) were only detected in surface water and groundwater in the sampling sites close to relatively older sewer systems, while they were absent in background samples that were collected from the catchment with no known wastewater sources. This suggests that ACT, CBZ, and SA can be used as specific molecular markers of raw wastewater in surface water and groundwater. This study also confirmed that CF and DEET were not really associated with wastewater sources, thus cannot serve well as specific molecular markers of wastewater contamination in receiving water bodies. To the best knowledge of the authors, the use of ACT and SA as specific molecular markers of raw wastewater contamination in urban surface waters and groundwater was first reported. Further studies on the use of ACT, CBZ, and SA along with other chemical/microbial markers are recommended to identify and differentiate contamination sources of surface waters/groundwater. PMID:24352549

  18. Delta Chromium-53/52 isotopic composition of native and contaminated groundwater, Mojave Desert, USA

    USGS Publications Warehouse

    Izbicki, John A.; Bullen, Thomas D.; Martin, Peter; Schroth, Brian

    2012-01-01

    Chromium(VI) concentrations in groundwater sampled from three contaminant plumes in aquifers in the Mojave Desert near Hinkley, Topock and El Mirage, California, USA, were as high as 2600, 5800 and 330 ?g/L, respectively. ?53/52Cr compositions from more than 50 samples collected within these plumes ranged from near 0‰ to almost 4‰ near the plume margins. Assuming only reductive fractionation of Cr(VI) to Cr(III) within the plume, apparent fractionation factors for ?53/52Cr isotopes ranged from ?app = 0.3 to 0.4 within the Hinkley and Topock plumes, respectively, and only the El Mirage plume had a fractionation factor similar to the laboratory derived value of ? = 3.5. One possible explanation for the difference between field and laboratory fractionation factors at the Hinkley and Topock sites is localized reductive fractionation of Cr(VI) to Cr(III), with subsequent advective mixing of native and contaminated water near the plume margin. Chromium(VI) concentrations and ?53/52Cr isotopic compositions did not uniquely define the source of Cr near the plume margin, or the extent of reductive fractionation within the plume. However, Cr(VI) and ?53/52Cr data contribute to understanding of the interaction between reductive and mixing processes that occur within and near the margins of Cr contamination plumes. Reductive fractionation of Cr(VI) predominates in plumes having higher ?app, these plumes may be suitable for monitored natural attenuation. In contrast, advective mixing predominates in plumes having lower ?app, the highly dispersed margins of these plumes may be difficult to define and manage.

  19. A top specified boundary layer (TSBL) approximation approach for the simulation of groundwater contamination processes

    USGS Publications Warehouse

    Rubin, H.; Buddemeier, R.W.

    1996-01-01

    This paper presents improvements in the 'classical boundary layer' (CBL) approximation method to obtain simple but robust initial characterization of aquifer contamination processes. Contaminants are considered to penetrate into the groundwater through the free surface of the aquifer. The improved method developed in this study is termed the 'top specified boundary layer' (TSBL) approach. It involves the specification of the contaminant concentration at the top of the contaminated 'region of interest' (ROI), which is simulated as a boundary layer. the TSBL modification significantly improves the ability of the boundary layer method to predict the development of concentration profiles over both space and time. The TSBL method can be useful for the simulation of cases in which the contaminant concentration is prescribed at the aquifer's free surface as well as for cases in which the contaminant mass flux is prescribed at the surface.

  20. Influence Of Groundwater Discharge On Arsenic Contamination In Sediments

    EPA Science Inventory

    A field investigation was conducted to evaluate the impact of a discharging arsenic plume on sediment contaminant characteristics at a site adjacent to a landfill in northeastern Massachusetts. Site characterization included assessment of the hydrologic and chemical samples coll...

  1. Evaluating Ecosystem Services for Reducing Groundwater Nitrate Contamination: Nitrate Attenuation in the Unsaturated and Saturated Zones

    NASA Astrophysics Data System (ADS)

    Wang, J.

    2013-12-01

    Nitrates are the most common type of groundwater contamination in agricultural regions. Environmental policies targeting nitrates have focused on input control (e.g., restricted fertilizer application), intermediate loads control (e.g., reduce nitrate leached from crop fields), and final loads control (e.g., reduce catchment nitrate loads). Nitrate loads can be affected by hydrological processes in both unsaturated and saturated zones. Although many of these processes have been extensively investigated in literature, they are commonly modeled as exogenous to farm management. A couple of recent studies by scientists from the Lawrence Livermore National Laboratory show that in some situations nitrate attenuation processes in the unsaturated/saturated zone, particularly denitrification, can be intensified by certain management practices to mitigate nitrate loads. Therefore, these nitrate attenuation processes can be regarded as a set of ecosystem services that farmers can take advantage of to reduce their cost of complying with environmental policies. In this paper, a representative California dairy farm is used as a case study to show how such ecosystem attenuation services can be framed within the farm owner's decision-making framework as an option for reducing groundwater nitrate contamination. I develop an integrated dynamic model, where the farmer maximizes discounted net farm profit over multiple periods subject to environmental regulations. The model consists of three submodels: animal-waste-crop, hydrologic, and economic model. In addition to common choice variables such as irrigation, fertilization, and waste disposal options, the farmer can also endogenously choose from three water sources: surface water, deep groundwater (old groundwater in the deep aquifer that is not affected by farm effluent in the short term), and shallow groundwater (drainage water that can be recycled via capture wells at the downstream end of the farm). The capture wells not only recycle wastewater, but can also increase the likelihood of denitrification. Thus the farmer essentially can choose whether, and to which extent, to install capture wells and take advantage of the ecosystem attenuation services. Decision rules from the dynamic optimization model demonstrate best management practices for the farm to improve its economic and environmental performance. I further use an economic valuation technique to value these services. Under the Millennium Ecosystem Assessment framework, nitrate attenuation in the unsaturated and saturated zone provides regulatory ecosystem services to humans, mainly nutrient regulation and waste treatment. With the integrated farm model, the production function approach is adopted to get the economic value of these regulatory services. The results highlight the significant role the environment can play in nitrate pollution control and potential benefits from designing policies that acknowledge this role. The most desirable policies are those that create incentive for farmers to use potential ecosystem services, which significantly reduce environmental compliance costs and increase social welfare.

  2. Baseline risk assessment of groundwater contamination at the Uranium Mill Tailings Site near Gunnison, Colorado. Revision 1

    SciTech Connect

    Not Available

    1994-04-01

    This report evaluates potential impacts to public health or the environment resulting from groundwater contamination at the former uranium mill processing site. The tailings and other contaminated material at this site are being placed in an off-site disposal cell by the US Department of Energy`s (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. Currently, the UMTRA Project is evaluating groundwater contamination. This is the second risk assessment of groundwater contamination at this site. The first risk assessment was performed primarily to evaluate existing domestic wells to determine the potential for immediate human health and environmental impacts. This risk assessment evaluates the most contaminated groundwater that flows beneath the processing site towards the Gunnison River. The monitor wells that have consistently shown the highest concentration of most contaminants are used in this risk assessment. This risk assessment will be used in conjunction with additional activities and documents to assist in determining what remedial action is needed for contaminated groundwater at the site after the tailings are relocated. This risk assessment follows an approach outlined by the US Environmental Protection Agency (EPA). The first step is to evaluate groundwater data collected from monitor wells at the site. Evaluation of these data showed that the main contaminants in the groundwater are cadmium, cobalt, iron, manganese, sulfate, uranium, and some of the products of radioactive decay of uranium.

  3. Source and plume investigation of chlorinated compounds in groundwater at a chemical plant

    SciTech Connect

    Trahan, D.B. [PSI, Inc., Baton Rouge, LA (United States)

    1995-10-01

    A site assessment was conducted to determine the distribution of chlorinated compounds in soil and groundwater at a chemical plant in Geismar, Louisiana. The assessment first included an investigation of the source(S) of the contaminants using aerial photos, interviews and plant records. Next, the stratigraphic framework of the site was defined with a hydrogeological investigation using historic borin logs and cone penetrometer testing (CPT). Finally, a plume investigation was performed to determine the horizontal and vertical extent of the contamination using direct-push methods for sampling of soil and groundwater. It was determined that chlorinated compounds originated from leaking drums and cleaning operations prior to 1975. Downward migration of these compounds may have been promoted by the installation of uncased 50-foot wooden pillings. The contamination is limited both vertical and horizontally, to three hydrogeologic zones: (1) the first water-bearing silt zone; (2) an intermediate zone consisting of interlayered silt and clay; and (3) the second water-bearing silt zone. The concentration of chlorinated compounds are greatest in the intermediate zone. There is some evidence of natural degradation of the chlorinated compounds, particularly in the first water-bearing zone.

  4. Atacama perchlorate as an agricultural contaminant in groundwater: isotopic and chronologic evidence from Long Island, New York.

    PubMed

    Böhlke, John Karl; Hatzinger, Paul B; Sturchio, Neil C; Gu, Baohua; Abbene, Irene; Mroczkowski, Stanley J

    2009-08-01

    Perchlorate (ClO4-) is a common groundwater constituent with both synthetic and natural sources. A potentially important source of ClO4- is past agricultural application of ClO4(-)-bearing natural NO3- fertilizer imported from the Atacama Desert, Chile, but evidence for this has been largely circumstantial. Here we report ClO4- stable isotope data (delta37Cl, delta18O, and delta17O), along with other supporting chemical and isotopic environmental tracer data, to document groundwater ClO4 contamination sources and history in parts of Long Island, New York. Sampled groundwaters were oxic and ClO4- apparently was not affected by biodegradation within the aquifers. Synthetic ClO4- was indicated by the isotopic method in groundwater near a fireworks disposal site at a former missile base. Atacama ClO4- was indicated in agricultural and urbanizing areas in groundwaters with apparent ages > 20 years. In an agricultural area, ClO4- concentrations and ClO4-/NO3- ratios increased with groundwater age, possibly because of decreasing application rates of Atacama NO3- fertilizers and/or decreasing ClO4- concentrations in Atacama NO3- fertilizers in recent years. Because ClO4-/NO3- ratios of Atacama NO3- fertilizers imported in the past (approximately 2 x 10(-3) mol mol(-1)) were much higher than the CO4-/NO3- ratio of recommended drinking-water limits (7 x 10(-5) mol mol(-1) in New York), ClO4- could exceed drinking-water limits even where NO3- does not, and where Atacama NO3- was only a minor source of N. Groundwater ClO4- with distinctive isotopic composition was a sensitive indicator of past Atacama NO3- fertilizer use on Long Island and may be common in other areas that received NO3- fertilizers from the late 19th century through the 20th century. PMID:19731653

  5. Development of a screening tool to assess the temporal risk of pesticides leaching to groundwater using the source, target, vector approach. An Irish case study for shallow groundwater.

    PubMed

    Labite, Herve E; Cummins, Enda

    2015-03-01

    During this study, a groundwater screening tool was developed to assess the temporal risk of groundwater contamination from the use of pesticides. It is based on a source, vector, target approach. The method utilised in this study uses a semi-quantitative probabilistic risk assessment where the input parameters were classified and assigned a relative score from 1 to 5 (i.e. 1?=?no risk and 5?=?high risk). The model was parameterised by using national data and calibrated with 2 years of national pesticide groundwater monitoring data. After calibration, two specific sites were selected for model validation. Based on the presence of the source, vector and target, the evaluation indicated that the temporal risk is site specific (i.e. May to December for the country model, June to September for the Oak Park site and September for the Castledockrell site). A sensitivity analysis performed on the national scale revealed that the groundwater vulnerability category (gv), the clay content (cc%), the persistence of pesticides in soil (DT50) and the rainfall represented by wet day (wd) were the most important parameters that affected model predictions (correlation coefficients of 0.54, -0.39, 0.35 and 0.31, respectively), highlighting the importance of soil hydrogeological conditions, soil type and rainfall in influencing water model predictions. The model developed can help to identify the temporal risk from pesticides to groundwater and guide regulators in highlighting at-risk periods, therefore allowing more focused monitoring programmes. PMID:25663403

  6. Modeling the impact of a benzene source zone on the transport behavior of PAHs in groundwater.

    PubMed

    Russold, Sandra; Schirmer, Mario; Piepenbrink, Matthias; Schirmer, Kristin

    2006-06-01

    Aquifers at industrial sites are commonly characterized by a multitude of contaminant source zones. Conceivably, dissolved contaminants originating from an up-gradient residual nonaqueous phase liquid (NAPL) source zone may be transported along the groundwater flow path into another residual NAPL source zone down-gradient. However, if and how contaminants from different zones may affect one another with regard to dissolution and transport has thus far been unknown. To identify and understand such potential interactions, the numerical model BIONAPL3D was applied to simulate the behavior of six dissolved polycyclic aromatic hydrocarbons (PAHs), stemming simultaneously from an up-gradient NAPL source zone, when they encounter a down-gradient NAPL source zone. The down-gradient NAPL source zone was assumed to be a residual benzene phase with a saturation of 10%. When the dissolved PAHs entered the benzene source zone, the aqueous PAH concentrations declined significantly due to their partitioning into the residual benzene phase. As benzene rapidly dissolved intothe aqueous phase,the PAHswere resolubilized with negligible impact due to benzene co-solvency. The degree of resolubilization was much smaller than the initial loss due to partitioning into the benzene phase. Thus, the PAHs formed a new residual NAPL phase that, over time, replaced the original benzene source zone. The new NAPL phase continued to grow even after all of the benzene was dissolved. Our modeling approach is the first theoretical demonstration of a significant interaction of contaminants emanating from multiple source zones. It should be regarded as a starting point to consider source zone interactions at polluted field sites. PMID:16786695

  7. Hydrogeologic controls on ground-water and contaminant discharge to the Columbia River near the Hanford Townsite

    Microsoft Academic Search

    S. P. Luttrell; D. R. Newcomer; S. S. Teel; V. R. Vermeul

    1992-01-01

    The purpose of this study is to quantify ground-water and contaminant discharge to the Columbia River in the Hanford Townsite vicinity. The primary objectives of the work are to: describe the hydrogeologic setting and controls on ground-water movement and contaminant discharge to the Columbia River; understand the river\\/aquifer relationship and its effects on contaminant discharge to the Columbia River; quantify

  8. In situ treatment of mixed contaminants in groundwater: Application of zero-valence iron and palladized iron for treatment of groundwater contaminated with trichloroethene and technetium-99

    SciTech Connect

    Korte, N.E.; Muck, M.T.; Zutman, J.L.; Schlosser, R.M. [Oak Ridge National Lab., Grand Junction, CO (United States); Liang, L.; Gu, B. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Siegrist, R.L. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; [Colorado School of Mines, Golden, CO (United States); Houk, T.C. [Portsmouth Gaseous Diffusion Plant, Piketon, OH (United States); Fernando, Q. [Univ. of Arizona, Tucson, AZ (United States)

    1997-04-01

    The overall goal of this portion of the project was to package one or more unit processes, as modular components in vertical and/or horizontal recirculation wells, for treatment of volatile organic compounds (VOCs) [e.g., trichloroethene (TCE)] and radionuclides [e.g., technetium (Tc){sup 99}] in groundwater. The project was conceived, in part, because the coexistence of chlorinated hydrocarbons and radionuclides has been identified as the predominant combination of groundwater contamination in the US Department of Energy (DOE) complex. Thus, a major component of the project was the development of modules that provide simultaneous treatment of hydrocarbons and radionuclides. The project objectives included: (1) evaluation of horizontal wells for inducing groundwater recirculation, (2) development of below-ground treatment modules for simultaneous removal of VOCs and radionuclides, and (3) demonstration of a coupled system (treatment module with recirculation well) at a DOE field site where both VOCs and radionuclides are present in the groundwater. This report is limited to the innovative treatment aspects of the program. A report on pilot testing of the horizontal recirculation system was the first report of the series (Muck et al. 1996). A comprehensive report that focuses on the engineering, cost and hydrodynamic aspects of the project has also been prepared (Korte et al. 1997a).

  9. Attenuation of groundwater contamination caused by cattle slurry: a plot-scale experimental study.

    PubMed

    López Periago, E; Núñez Delgado, A; Díaz-Fierros, F

    2002-09-01

    Infiltration of contaminants was investigated in a flat pasture plot Lolium perenne L. which received 250 m3/ha of cattle slurry. Lysimeters and piezometers had previously been installed in the plot to sample groundwater at different depths. Water samples were analysed for pH, conductivity, NH4(+), NO3-, orthophosphate, Cl-, Na+, K+, Ca2+, Mg2+ and chemical oxygen demand (COD), and for faecal coliforms and faecal streptococci. Contaminant concentrations in water samples taken in lysimeters at a depth of 5 cm (2 h after slurry application) were already from 22% to 83%, of raw slurry. After slurry application and after 150 mm of rainfall, contaminant concentrations in groundwater were in all depths less than 95% of those initially measured in the slurry. For all contaminants except Cl-, NO3-, K+ and COD, concentrations in groundwater measured before application were reached within 15 days. Mechanical retention was the principal mechanism of attenuation of microorganism and COD levels, whereas cations were attenuated by sorption to soil matrix. Dilution by rain water had less significant effects, accounting for about a tenfold reduction in contaminant levels. PMID:12139326

  10. Development of one-dimensional computational fluid dynamics code 'GFLOW' for groundwater flow and contaminant transport analysis

    SciTech Connect

    Rahatgaonkar, P. S.; Datta, D.; Malhotra, P. K.; Ghadge, S. G. [Nuclear Power Corporation of India Ltd., R-2, Ent. Block, Nabhikiya Urja Bhavan, Anushakti Nagar, Mumbai - 400 094 (India)

    2012-07-01

    Prediction of groundwater movement and contaminant transport in soil is an important problem in many branches of science and engineering. This includes groundwater hydrology, environmental engineering, soil science, agricultural engineering and also nuclear engineering. Specifically, in nuclear engineering it is applicable in the design of spent fuel storage pools and waste management sites in the nuclear power plants. Ground water modeling involves the simulation of flow and contaminant transport by groundwater flow. In the context of contaminated soil and groundwater system, numerical simulations are typically used to demonstrate compliance with regulatory standard. A one-dimensional Computational Fluid Dynamics code GFLOW had been developed based on the Finite Difference Method for simulating groundwater flow and contaminant transport through saturated and unsaturated soil. The code is validated with the analytical model and the benchmarking cases available in the literature. (authors)

  11. Ground-water contamination from lead shot at Prime Hook National Wildlife Refuge, Sussex County, Delaware

    USGS Publications Warehouse

    Soeder, Daniel J.; Miller, Cherie V.

    2003-01-01

    Prime Hook National Wildlife Refuge is located in southeastern Delaware in coastal lowlands along the margin of Delaware Bay. For 37 years, the Broadkiln Sportsman?s Club adjacent to the refuge operated a trap-shooting range, with the clay-target launchers oriented so that the expended lead shot from the range dropped into forested wetland areas on the refuge property. Investigators have estimated that up to 58,000 shotgun pellets per square foot are present in locations on the refuge where the lead shot fell to the ground. As part of the environmental risk assessment for the site, the U.S. Geological Survey (USGS) investigated the potential for lead contamination in ground water. Results from two sampling rounds in 19 shallow wells indicate that elevated levels of dissolved lead are present in ground water at the site. The lead and associated metals, such as antimony and arsenic (common shotgun pellet alloys), are being transported along shallow ground-water flowpaths toward an open-water slough in the forested wetland adjacent to the downrange target area. Water samples from wells located along the bank of the slough contained dissolved lead concentrations higher than 400 micrograms per liter, and as high as 1 milligram per liter. In contrast, a natural background concentration of lead from ground water in a well upgradient from the site is about 1 microgram per liter. Two water samples collected several months apart from the slough directly downgradient of the shooting range contained 24 and 212 micrograms per liter of lead, respectively. The data indicate that lead from a concentrated deposit of shotgun pellets on the refuge has been mobilized through a combination of acidic water conditions and a very sandy, shallow, unconfined aquifer, and is moving along ground-water flowpaths toward the surface-water drainage. Data from this study will be used to help delineate the lead plume, and determine the fate and transport of lead from the source area.

  12. Second moment method for evaluating human health risks from groundwater contaminated by trichloroethylene.

    PubMed Central

    Jacobs, T L; Warmerdam, J M; Medina, M A; Piver, W T

    1996-01-01

    Pollutants in groundwater aquifers may constitute a significant human health risk. A large variation in response may result among human populations experiencing the same level and duration of exposure to pollutants. Variability in response, as a result of exposure to a carcinogenic contaminant such as trichloroethylene (TCE), can be represented by a distribution function of safe doses. Spatial variability in aquifer characteristics and contaminant transport parameters requires the use of stochastic transport models to quantify variability in exposure concentrations. A second moment method is used to evaluate the probability of exceeding safe dose levels for a contaminated aquifer. The name of this method stems from the fact that the formulation is based on the first and second moments of the random variables. With this method, the probability is a function of the variability of contaminant concentration (which incorporates variability in hydrogeologic parameters such as hydraulic conductivity) and the variability in response in the human population. In this manner, the severity of the health risk posed by a contaminated aquifer and the evaluation of appropriate strategies and technologies for aquifer remediation are a function of contaminant concentrations and human health risks. The applicability and limitations of this method are demonstrated with data on groundwater contaminated by TCE at Hill Air Force Base, Utah. Images Figure 1. Figure 2. Figure 3. Figure 4. PMID:8875161

  13. Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies in Indiana

    USGS Publications Warehouse

    Arihood, Leslie D.; Cohen, David A.

    2006-01-01

    The Safe Water Drinking Act of 1974 as amended in 1996 gave each State the responsibility of developing a Source-Water Assessment Plan (SWAP) that is designed to protect public-water supplies from contamination. Each SWAP must include three elements: (1) a delineation of the source-water protection area, (2) an inventory of potential sources of contaminants within the area, and (3) a determination of the susceptibility of the public-water supply to contamination from the inventoried sources. The Indiana Department of Environmental Management (IDEM) was responsible for preparing a SWAP for all public-water supplies in Indiana, including about 2,400 small public ground-water supplies that are designated transient, non-community (TNC) supplies. In cooperation with IDEM, the U.S. Geological Survey compiled information on conditions near the TNC supplies and helped IDEM complete source-water assessments for each TNC supply. The delineation of a source-water protection area (called the assessment area) for each TNC ground-water supply was defined by IDEM as a circular area enclosed by a 300-foot radius centered at the TNC supply well. Contaminants of concern (COCs) were defined by IDEM as any of the 90 contaminants for which the U.S. Environmental Protection Agency has established primary drinking-water standards. Two of these, nitrate as nitrogen and total coliform bacteria, are Indiana State-regulated contaminants for TNC water supplies. IDEM representatives identified potential point and nonpoint sources of COCs within the assessment area, and computer database retrievals were used to identify potential point sources of COCs in the area outside the assessment area. Two types of methods-subjective and subjective hybrid-were used in the SWAP to determine susceptibility to contamination. Subjective methods involve decisions based upon professional judgment, prior experience, and (or) the application of a fundamental understanding of processes without the collection and analysis of data for a specific condition. Subjective hybrid methods combine subjective methods with quantitative hydrologic analyses. The subjective methods included an inventory of potential sources and associated contaminants, and a qualitative description of the inherent susceptibility of the area around the TNC supply. The description relies on a classification of the hydrogeologic and geomorphic characteristics of the general area around the TNC supply in terms of its surficial geology, regional aquifer system, the occurrence of fine- and coarse-grained geologic materials above the screen of the TNC well, and the potential for infiltration of contaminants. The subjective hybrid method combined the results of a logistic regression analysis with a subjective analysis of susceptibility and a subjective set of definitions that classify the thickness of fine-grained geologic materials above the screen of a TNC well in terms of impedance to vertical flow. The logistic regression determined the probability of elevated concentrations of nitrate as nitrogen (greater than or equal to 3 milligrams per liter) in ground water associated with specific thicknesses of fine-grained geologic materials above the screen of a TNC well. In this report, fine-grained geologic materials are referred to as a geologic barrier that generally impedes vertical flow through an aquifer. A geologic barrier was defined to be thin for fine-grained materials between 0 and 45 feet thick, moderate for materials between 45 and 75 feet thick, and thick if the fine-grained materials were greater than 75 feet thick. A flow chart was used to determine the susceptibility rating for each TNC supply. The flow chart indicated a susceptibility rating using (1) concentrations of nitrate as nitrogen and total coliform bacteria reported from routine compliance monitoring of the TNC supply, (2) the presence or absence of potential sources of regulated contaminants (nitrate as nitrogen and coliform bac

  14. Rooftop Runoff as a Source of Contamination: A Review

    EPA Science Inventory

    Scientific reports concerning chemical and microbiological contaminant levels of rainwater runoff from rooftop collection in both urban and rural areas are reviewed. This alternative source of water has been documented to often contain substantial amounts of contaminants. Studi...

  15. Activated Peroxygens for Remediation of Contaminated Soil and Groundwater

    E-print Network

    Hansen, René Rydhof

    or persulfate into the subsurface in order to transform contaminants into less harmful compounds. The use of activated peroxygens (hydrogen peroxide and persulfate) for ISCO holds promise for rapid destruction persulfate (ASP) as the most widely applied. In MFR, decomposition of hydrogen peroxide is catalyzed

  16. Contamination of Groundwater Systems in the US and Canada by Enteric Pathogens, 1990–2013: A Review and Pooled-Analysis

    PubMed Central

    Hynds, Paul Dylan; Thomas, M. Kate; Pintar, Katarina Dorothy Milena

    2014-01-01

    Background Up to 150 million North Americans currently use a groundwater system as their principal drinking water source. These systems are a potential source of exposure to enteric pathogens, contributing to the burden of waterborne disease. Waterborne disease outbreaks have been associated with US and Canadian groundwater systems over the past two decades. However, to date, this literature has not been reviewed in a comprehensive manner. Methods and Principal Findings A combined review and pooled-analysis approach was used to investigate groundwater contamination in Canada and the US from 1990 to 2013; fifty-five studies met eligibility criteria. Four study types were identified. It was found that study location affects study design, sample rate and studied pathogen category. Approximately 15% (316/2210) of samples from Canadian and US groundwater sources were positive for enteric pathogens, with no difference observed based on system type. Knowledge gaps exist, particularly in exposure assessment for attributing disease to groundwater supplies. Furthermore, there is a lack of consistency in risk factor reporting (local hydrogeology, well type, well use, etc). The widespread use of fecal indicator organisms in reported studies does not inform the assessment of human health risks associated with groundwater supplies. Conclusions This review illustrates how groundwater study design and location are critical for subsequent data interpretation and use. Knowledge gaps exist related to data on bacterial, viral and protozoan pathogen prevalence in Canadian and US groundwater systems, as well as a need for standardized approaches for reporting study design and results. Fecal indicators are examined as a surrogate for health risk assessments; caution is advised in their widespread use. Study findings may be useful during suspected waterborne outbreaks linked with a groundwater supply to identify the likely etiological agent and potential transport pathway. PMID:24806545

  17. Evidence for Groundwater Contamination Vulnerability in California?s Central Valley

    SciTech Connect

    Moran, J E; Leif, R; Esser, B K; Singleton, M J

    2005-12-13

    The California Water Resources Control Board, in collaboration with the US Geological Survey and Lawrence Livermore National Laboratory, has implemented a program to assess the susceptibility of groundwater resources. Advanced techniques such as groundwater age dating using the tritium-helium method, extensive use of oxygen isotopes of the water molecule ({delta}{sup 18}O) for recharge water provenance, and analysis of common volatile organic compounds (VOCs) at ultra-low levels are applied with the goal of assessing the contamination vulnerability of deep aquifers, which are frequently used for public drinking water supply. Over 1200 public drinking water wells have been tested to date, resulting in a very large, tightly spaced collection of groundwater ages in some of the heavily exploited groundwater basins of California. Smaller scale field studies that include shallow monitoring wells are aimed at assessing the probability that nitrate will be transported to deep drinking water aquifers. When employed on a basin-scale, groundwater ages are an effective tool for identifying recharge areas, defining flowpaths, and determining the rate of transport of water and entrained contaminants. De-convolution of mixed ages, using ancillary dissolved noble gas data, gives insight into the water age distribution drawn at a well, and into the effective dilution of contaminants such as nitrate at long-screened production wells. In combination with groundwater ages, low-level VOCs are used to assess the impact of vertical transport. Special studies are focused on the fate and transport of nitrate with respect to vulnerability of aquifers in agricultural and formerly agricultural areas.

  18. Groundwater and Air Contamination: Risk, Toxicity, Exposure Assessment, Policy, and Regulation

    NASA Astrophysics Data System (ADS)

    Watts, R. J.; Teel, A. L.

    2003-12-01

    The improper disposal of hazardous wastes and subsequent contamination of surface and groundwaters has exposed the public and ecosystems to toxic chemicals that have detrimental consequences. The cost of cleaning up the thousands of hazardous waste sites throughout the world is daunting, and the effort to do so is economically impractical. As a result, some level of contamination will always remain, both locally and globally. The presence of a residual level of contamination carries with it the probability of negative impacts on the world's population; e.g., enhanced risk of cancer or the onset of neurological disorders. Risk is the probability of such events. Risk assessments are routinely performed at contaminated sites and in areas of widespread environmental contamination, such as an entire aquifer, as a means of quantifying the potential threats to public health and to ecosystems.

  19. Suburban groundwater quality as influenced by turfgrass and septic sources, delmarva peninsula, USA.

    PubMed

    Kasper, Joshua W; Denver, Judith M; York, Joanna K

    2015-03-01

    Suburban land use is expanding in many parts of the United States and there is a need to better understand the potential water-quality impacts of this change. This study characterized groundwater quality in a sandy, water-table aquifer influenced by suburban development and compared the results to known patterns in water chemistry associated with natural, background conditions and agricultural effects. Samples for nutrients, major ions, and isotopes of N and O in NO were collected in 2011 beneath turfgrass from 29 shallow wells (median depth 3.7 m) and from 18 deeper wells (median depth 16.9 m) in a long-term suburban development. Nitrate (as N) concentrations in groundwater beneath turfgrass were highly variable (0.02-22.3 mg L) with a median of 2.7 mg L, which is higher than natural water chemistry (>0.4 mg L; Na-Cl-HCO water type), but significantly lower than concentrations beneath a nearby agricultural area (median 16.9 mg L; < .0001). Dissolved Fe concentrations in shallow suburban groundwater, attributed to chelated Fe in turfgrass fertilizers, were significantly higher ( < .005) than concentrations from the agricultural site, although a Ca-Mg-Cl-NO water type was dominant in both areas. A Na-Cl-NO water type indicated a septic-system source for nitrate in deep suburban groundwater (0.06-6.0 mg L; median 1.5 mg L). Isotopic data indicated denitrification; however, geochemical techniques were more helpful in identifying nitrate sources. Results indicate that suburban expansion into agricultural areas may significantly decrease overall nitrate concentrations in groundwater, but excessive turfgrass fertilization could result in localized contamination. PMID:26023982

  20. Influence of surface water/groundwater interactions on stream and wetland water quality: analytical solutions for coupled contaminant transport equations

    NASA Astrophysics Data System (ADS)

    Melek Kazezyilmaz-Alhan, Cevza

    2014-05-01

    Wetlands are located in transitional zones between uplands and downstream flooded systems and surface water/groundwater interactions are frequently observed especially in riparian wetlands where the water level fluctuates frequently during the rainy season. Moreover, surface water/groundwater interactions also influence the characteristics of contaminant transport in pools and riffles, and in meandering type of streams. Therefore, it is important to investigate and solve these processes accurately to improve the prediction of downstream water quality. Although there are many experimental and numerical studies available in the literature which discuss and model the surface water/ground water interactions in streams and wetlands, very few analytical solutions have been conducted. Analytical solutions are helpful tools for verification of numerical solutions and they provide fast and accurate results for practical problems. Furthermore, they provide an understanding to the influence of each parameter in hydrological and contaminant transport models for streams and wetlands. In order to contribute to the research in understanding the behavior of water quality in streams and wetlands, analytical solutions are developed for the coupled contaminant transport equations of several transient storage and wetland models. Among these models are the wetland model WETland Solute TrANsport Dynamics (WETSAND) developed by Kazezyilmaz-Alhan et al. (2007), the transient storage models developed by Bencala and Walters (1983), and Kazezyilmaz-Alhan and Medina (2006). WETSAND is a general comprehensive wetland model, which has both surface flow and solute transport components. In this wetland model, water quality components are solved by advection-dispersion-reaction equations which incorporate surface water/groundwater interactions by including the incoming/outgoing mass due to the groundwater recharge/discharge. The transient storage model developed by Bencala and Walters (1983) solves the contaminant distribution between main streams and stagnant zones. The transient storage is represented by the mass exchange due to the concentration difference between the stream and the storage zone in this model. The transient storage model developed by Kazezyilmaz-Alhan and Medina (2006) involves several improvements to the transient storage model of Bencala and Walters (1983): advection and dispersion processes are incorporated into the contaminant transport in hyporheic zone and the mass transport between the channel and hyporheic zone is represented by mass flux terms. The solutions of the governing equations are obtained for continuous source type of boundary conditions. Results show that analytical solutions are in good agreement with the numerical solutions.

  1. Predicting long-term contamination potential of perched groundwater in a mine-waste heap using a random-walk method

    Microsoft Academic Search

    Catherine J. Gandy; Paul L. Younger

    2008-01-01

    Mine-waste heaps are potential long-term sources of contamination for surface-water courses and groundwater systems. Application\\u000a of a novel physically based particle-tracking model to a mine-waste heap in northern England, UK, has enabled predictions\\u000a to be made of the lifetime of contaminants leaching, revealing a pattern of source-mineral depletion. A mine-waste heap is\\u000a conceptualised by a series of one-dimensional unsaturated “columns”

  2. Application of synchrotron X-ray fluorescence spectroscopy and energy dispersive X-ray analysis to identify contaminant metals on groundwater colloids

    SciTech Connect

    Kaplan, D.I.; Hunter, D.B.; Bertsch, P.M.; Adrlano, D.C. (Univ. of Georgia, Aiken, SC (United States)); Bajt, S. (Univ. of Chicago, IL (United States) Brookhaven National Lab., Upton, NY (United States))

    1994-06-01

    The objective of this study was to combine the results from SXRF and EDX to provide information about the elemental composition of individual groundwater colloids and about the identity of contaminants associated with these colloids. Because the contaminant metals in the study site came from a point source, their presence on groundwater colloids would provide elemental signatures suggesting that colloids may be important in contaminant transport. SXRF was used to detect low concentrations of contaminant metals associated with surfaces of clusters of groundwater colloids. EDX was used to detect the more abundant elements (including the geochemically important, lower atomic number elements Al and Si that are insensitive to SXRF) associated with surfaces of individual colloids. These techniques were also selected because they require only a small sample mass, about 0.01 g, which may be the total quantity of colloids recovered from 24 h of groundwater sampling. The study site was an aquifer underlying unlined seepage basins that had received wastewater containing sodium hydroxide, nitric acid, radionuclides, and numerous metals from a nuclear materials processing facility on the Savannah River Site near Aiken, SC. 12 refs., 2 figs., 2 tabs.

  3. Groundwater arsenic contamination on the Ganges Delta: biogeochemistry, hydrology, human perturbations, and human suffering on a large scale

    NASA Astrophysics Data System (ADS)

    Harvey, Charles F.; Swartz, Christopher H.; Badruzzaman, Abu Bohran M.; Keon-Blute, Nicole; Yu, Winston; Ali, M. Ashraf; Jay, Jenny; Beckie, Roger; Niedan, Volker; Brabander, Daniel; Oates, Peter M.; Ashfaque, Khandaker N.; Islam, Shafiqul; Hemond, Harold F.; Ahmed, M. Feroze

    2005-02-01

    Over the last several decades, much of population of Bangladesh and West Bengal switched their water supply from surface water to groundwater. Tragically, much of the region's groundwater is dangerously contaminated by arsenic, and consumption of this water has already created severe health effects. Here we consider how groundwater flow may affect arsenic biogeochemistry and we compare the vertical patterns of groundwater chemistry at our intensive study site with the average values across the country. Detailed hydraulic data are presented from our field site that begins to characterize the groundwater flow system. To cite this article: C.F. Harvey et al., C. R. Geoscience 337 (2005).

  4. Structural diversity of organochlorine compounds in groundwater affected by an industrial point source.

    PubMed

    Frische, Kerstin; Schwarzbauer, Jan; Ricking, Mathias

    2010-09-01

    Groundwater samples contaminated by an industrial point source were analysed in order to reveal the structural diversity of halogenated organic contaminants. Particular focus was laid on the metabolites and derivatives related to the pesticides DDT (2,2-bis(chlorophenyl)-1,1,1-trichlorethane) and lindane (?-hexachlorocyclohexane). Additionally, a wide range of chlorinated and brominated xenobiotics were identified. These results represent a high degree of contamination with organochlorine compounds illustrating a considerable structural diversity in groundwater in the vicinity of the industrial plant. The polar DDT-metabolite DDA (2,2-bis(chlorophenyl)acetic acid), which has been neglected in water studies widely, represents the main DDT metabolite analysed in the water samples. Besides DDA, some unknown substances with structural relation to DDA and DDT were detected and identified, in detail 2,2-bis(4-chlorophenyl)acetic acid N-methyl amide (DDAMA) and 2,2-bis(4-chlorophenyl)acetic acid n-butyl ester (DDABE). As an overall implication of this study it has to be demanded that analysis of industrially affected ground waters have to be based on screening analysis for a comprehensive view on the state of pollution. PMID:20810145

  5. Mobilization of arsenic and other naturally occurring contaminants in groundwater of the Main Ethiopian Rift aquifers.

    PubMed

    Rango, Tewodros; Vengosh, Avner; Dwyer, Gary; Bianchini, Gianluca

    2013-10-01

    This study investigates the mechanisms of arsenic (As) and other naturally occurring contaminants (F(-), U, V, B, and Mo) mobilization from Quaternary sedimentary aquifers of the Main Ethiopian Rift (MER) and their enrichment in the local groundwater. The study is based on systematic measurements of major and trace elements as well as stable oxygen and hydrogen isotopes in groundwater, coupled with geochemical and mineralogical analyses of the aquifer rocks. The Rift Valley aquifer is composed of rhyolitic volcanics and Quaternary lacustrine sediments. X-ray fluorescence (XRF) results revealed that MER rhyolites (ash, tuff, pumice and ignimbrite) and sediments contain on average 72 wt. % and 65 wt. % SiO2, respectively. Petrographic studies of the rhyolites indicate predominance of volcanic glass, sanidine, pyroxene, Fe-oxides and plagioclase. The As content in the lacustrine sediments (mean = 6.6 mg/kg) was higher than that of the rhyolites (mean: 2.5 mg/kg). The lacustrine aquifers of the Ziway-Shala basin in the northern part of MER were identified as high As risk zones, where mean As concentration in groundwater was 22.4 ± 33.5 (range of 0.60-190 ?g/L) and 54% of samples had As above the WHO drinking water guideline value of 10 ?g/L. Field As speciation measurements showed that most of the groundwater samples contain predominantly (~80%) arsenate-As(V) over arsenite-As(III) species. The As speciation together with field data of redox potential (mean Eh = +73 ± 65 mV) and dissolved-O2 (6.6 ± 2.2 mg/L) suggest that the aquifer is predominantly oxidative. Water-rock interactions, including the dissolution of volcanic glass produces groundwater with near-neutral to alkaline pH (range 6.9-8.9), predominance of Na-HCO3 ions, and high concentration of SiO2 (mean: 85.8 ± 11.3 mg/L). The groundwater data show high positive correlation of As with Na, HCO3, U, B, V, and Mo (R(2) > 0.5; p < 0.001). Chemical modeling of the groundwater indicates that Fe-oxides and oxyhydroxides minerals were saturated in the groundwater, suggesting that the As reactivity is controlled by adsorption/desorption processes with these minerals. The data show that As and other oxyanion-forming elements such as U, B, Mo, and V had typically higher concentrations at pH > ~8, reflecting the pH-dependence of their mobilization. Based on the geochemical and stable isotope variations we have established a conceptual model for the occurrence of naturally occurring contaminants in MER groundwater: 1) regional groundwater recharge from the Highland, along the Rift margins, followed by lateral flow and water-rock interactions with the aquifer rocks resulted in a gradual increase of the salinity and naturally occurring contaminants towards the center of the valley; and (2) local ?(18)O-rich lake water recharge into adjacent shallow aquifers, followed by additional mobilization of As and other oxyanion-forming elements from the aquifer rocks. We posit that the combined physical-chemical conditions of the aquifers such as oxidizing state, Na-HCO3 composition, and pH>~8 lead to enhanced mobilization of oxyanion-forming elements from Fe-oxides and consequently contamination of local groundwater. These geochemical conditions characterize groundwater resources along the Eastern African Rift and thus constitute a potential threat to the quality of groundwater in larger areas of Eastern Africa. PMID:23899878

  6. HISTORICAL CONTAMINATION OF GROUNDWATER RESOURCES IN THE NORTH COAST KARST AQUIFERS OF PUERTO RICO

    PubMed Central

    Padilla, Ingrid; Irizarry, Celys; Steele, Katherine

    2012-01-01

    The North Coast Karst Aquifer System of Puerto Rico is the island’s most productive aquifer. The characteristics that make it highly productive also make it vulnerable to contamination. This research, which addresses the historical contamination of groundwater resources in the northern karst region was conducted through integration of spatial hydrogeologic and contaminant concentration data in the La Plata-Arecibo area. The study used GIS technologies and focused on phthalates and chlorinated volatile organic compounds (CVOCs) and phthalates due to their ubiquitous presence in the environment as well as their presence in listed and potential superfund sites in Puerto Rico and U.S. and potential for exposure and health impacts. Results show an extensive historical contamination of the groundwater resources in the northern karst aquifers. Long-term contamination indicates the aquifers’ large capacity for storing and releasing contaminants and reflects a long-term potential for exposure. The degradation of this important water resource has resulted in a subsequent reduction of the extraction capacity and an increase in the cost of use. PMID:24772197

  7. Multiple sources of boron in urban surface waters and groundwaters.

    PubMed

    Hasenmueller, Elizabeth A; Criss, Robert E

    2013-03-01

    Previous studies attribute abnormal boron (B) levels in streams and groundwaters to wastewater and fertilizer inputs. This study shows that municipal drinking water used for lawn irrigation contributes substantial non-point loads of B and other chemicals (S-species, Li, and Cu) to surface waters and shallow groundwaters in the St. Louis, Missouri, area. Background levels and potential B sources were characterized by analysis of lawn and street runoff, streams, rivers, springs, local rainfall, wastewater influent and effluent, and fertilizers. Urban surface waters and groundwaters are highly enriched in B (to 250?g/L) compared to background levels found in rain and pristine, carbonate-hosted streams and springs (<25?g/L), but have similar concentrations (150 to 259?g/L) compared to municipal drinking waters derived from the Missouri River. Other data including B/SO4(2-)-S and B/Li ratios confirm major contributions from this source. Moreover, sequential samples of runoff collected during storms show that B concentrations decrease with increased discharge, proving that elevated B levels are not primarily derived from combined sewer overflows (CSOs) during flooding. Instead, non-point source B exhibits complex behavior depending on land use. In urban settings B is rapidly mobilized from lawns during "first flush" events, likely representing surficial salt residues from drinking water used to irrigate lawns, and is also associated with the baseflow fraction, likely derived from the shallow groundwater reservoir that over time accumulates B from drinking water that percolates into the subsurface. The opposite occurs in small rural watersheds, where B is leached from soils by recent rainfall and covaries with the event water fraction. PMID:23384647

  8. Estimation of the time component in the movement of chemicals in contaminated groundwater.

    PubMed Central

    Freni, S C; Phillips, D L

    1987-01-01

    For a proper analysis of the potentially causal relationship between exposure to volatile organic chemicals (VOCs) in drinking water and health events, it is essential to know T1, the time when exposure started, and C = f(T), which is the change of the VOC concentration C as a function of time T and the total accumulated exposure (TAE) to VOCs to which an individual was exposed. In the typical situation of incidentally detected pollution of groundwater, no such information is available. This paper describes the development of a method for estimating T1, C = f(T), and TAE as part of an epidemiologic study of the health effects of VOC contamination of an aquifer serving public and private wells. Pooled test results of city wells, tested periodically since 1981, provided the data base for developing a statistical model for estimating C = f(T). This model was then applied to private wells, for which the data of only one water sample were available, to retrospectively estimate their T1. The best-fitting model was a multiple linear regression equation consisting of the natural logarithm of the VOC concentration as the response variable, with the time of sampling, the distance of the wells from the source (expressed as coordinates), the well depth, and the well capacity as determinants. The TAE was calculated by integrating the area under the time-concentration curve. PMID:3691428

  9. 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.

  10. COMBINATION OF A SOURCE REMOVAL REMEDY AND BIOREMEDIATION FOR THE TREATMENT OF A TCE CONTAMINATED AQUIFER

    EPA Science Inventory

    Historical disposal practices of chlorinated solvents have resulted in the widespread contamination of ground-water resources. These ground-water contaminants exist in the subsurface as free products, residual and vapor phases, and in solution. The remediation of these contamin...

  11. [Spatial and temporal variability of nitrate contaminant in groundwater in Jinfo Mt. area, Chongqing, China].

    PubMed

    Wu, Kun-Yu; Wang, Peng; Shen, Li-Cheng; Xiao, Qiong

    2011-11-01

    The geochemical background of nitrate in groundwater in Jinfo Mt. area was determined, and spatial and temporal variability of nitrate contaminant was analyzed using geochemical, statistical and GIS methods. Twenty-three samples were collected from groundwater discharge points in the study area during 1976-1977, 2004-2006 and 2009, and mass concentration of nitrate in groundwater was tested. The results showed that the geochemical background of nitrate in groundwater in study area was in the range of 0.72-2. 00 mg x L(-1), and the threshold of anomaly was 3.20 mg x L(-1). During 2004-2006 and 2009, the average values of nitrate concentration in groundwater in Jinfo Mt. natural reserve were 2.08, 2.67, 2.59 and 3.92 mg x L(-1); and were 39.08, 25.46, 17.99 and 13.73 mg x L(-1) in the groundwater out of the reserve; the average over-limit rates (standard limit NO3(-) -N < or = 10mg x L(-1)) were 451.64%, 478.61%, 331.85% and 145.67%; the maximum over-limit rates were 1 475.81%, 1 080.39%, 538.20% and 361.78%. Results of interpolation showed that the high value centers of nitrate concentration in groundwater in study area were changing over time, but districts with low nitrate concentration in groundwater in study area were distributed along Jinfo Mt. natural reserve. The application of environmental policy measures and industrial restructuring implemented were reasonable and successful, which had a positive effect to environmental protection. PMID:22295620

  12. Evaluation of the origin of nitrate influencing the Klju? groundwater source, Serbia.

    PubMed

    Miljevi?, Nada; Boreli-Zdravkovi?, Djulija; Obradovi?, Vesna; Golobo?anin, Dušan; Mayer, Bernhard

    2012-01-01

    This paper describes the use of the dual isotope method involving ?(15)N and ?(18)O measurements of dissolved nitrates to assess the origin and fate of groundwater nitrate at the Klju? groundwater source, Serbia. A sampling campaign was conducted in September 2007 during flow conditions obtaining groundwater from observation wells and river water fed by a shallow aquifer hosted in alluvial (sandy-gravel) sediments. Nitrate isotope ratios ranged from +5.3 to +16.9‰ and ?(18)O(NO(3)) values varied from -2.3 to +5.0‰. Two major contamination sources were identified with isotopic compositions characteristic for nitrate derived from nitrification of soil organic nitrogen (+5.3 to +7.8‰ for ?(15)N) resulting in nitrate concentrations of 33.6 and 78.8 mg/L and nitrate derived from animal wastes or human sewage, e.g. via septic systems, yielding ?(15)N values of +9.9 to +11.9‰ and elevated nitrate concentrations of 31.2-245.8 mg/L. The occurrence of nitrification and denitrification was also revealed based on concentration and isotope data for dissolved nitrate. PMID:22744675

  13. Microbial contamination of groundwater at small community water supplies in Finland.

    PubMed

    Pitkänen, Tarja; Karinen, Päivi; Miettinen, Ilkka T; Lettojärvi, Heidi; Heikkilä, Annika; Maunula, Reetta; Aula, Vesa; Kuronen, Henry; Vepsäläinen, Asko; Nousiainen, Liina-Lotta; Pelkonen, Sinikka; Heinonen-Tanski, Helvi

    2011-06-01

    The raw water quality and associations between the factors considered as threats to water safety were studied in 20 groundwater supplies in central Finland in 2002-2004. Faecal contaminations indicated by the appearance of Escherichia coli or intestinal enterococci were present in five small community water supplies, all these managed by local water cooperatives. Elevated concentrations of nutrients in raw water were linked with the presence of faecal bacteria. The presence of on-site technical hazards to water safety, such as inadequate well construction and maintenance enabling surface water to enter into the well and the insufficient depth of protective soil layers above the groundwater table, showed the vulnerability of the quality of groundwater used for drinking purposes. To minimize the risk of waterborne illnesses, the vulnerable water supplies need to be identified and appropriate prevention measures such as disinfection should be applied. PMID:21809781

  14. [Review of dual stable isotope technique for nitrate source identification in surface- and groundwater in China].

    PubMed

    Xu, Zhi-Wei; Zhang, Xin-Yu; Yu, Gui-Rui; Sun, Xiao-Min; Wen, Xue-Fa

    2014-08-01

    Water nitrate (NO3-) contamination is a world-wide environmental problem under the effects of intensive human activities. Sources identification of NO3- contamination in water is important for better management of water quality. Dual stable isotope data of nitrate nitrogen (delta15N) and nitrate oxygen (delta18O) combined with other stable isotopes and chemical analysis data have been frequently used to identify NO3- sources, differentiate percentage of the different NO3- sources and assess the nitrification/denitrification processes of surface water, groundwater and precipitation, respectively. This review summarized the analysis technique of nitrate delta15N and delta18O in domestic and abroad, assessed typical values of delta15N, delta18O from different NO3- sources and evaluated the progress in application of dual stable isotope of delta15N and delta18O technique to trace NO3- sources in surface- and ground-water. Both ion exchange-AgNO3 and bacteria denitrifying methods have been successfully used in tracing water nitrate sources nationwide. The comprehensive metadata analysis of nitrate sources showed that the delta15N values of sewage and manure, soil, precipitation, fertilizer ranged from 3 per thousand to 17 per thousand, 3 per thousand to 8 per thousand, - 9 per thousand to 9 per thousand, -2 per thousand to 4 per thousand, respectively. And the delta15N values of ammonium fertilizer ranged from - 4 per thousand to 2 per thousand. According to the stable isotope technique, sewage and manure were identified as the major nitrate sources of surface- and ground-water in China. This indicated that municipal sewage and aquaculture exerted serious influence on the nitrate pollution of surface water. In the future, long-term monitoring, dual stable isotope fingerprinting and hydro-chemical analysis should be applied together to quantitatively differentiate contribution of nitrate sources, and to assess seasonal dynamic of nitrate sources. It will provide useful scientific basis for water environmental management of China. PMID:25338404

  15. Development of Hydro-Epidemiology Studies to Establish Relationships Between Source-Water Contamination and Preterm Birth

    NASA Astrophysics Data System (ADS)

    Padilla, I. Y.; Meeker, J.; Alshawabkeh, A.; Cordero, J.; Giese, R.; Loch-Caruso, R.

    2010-12-01

    Puerto Rico has the highest rate of preterm birth in United States. Preliminary investigations suggest that the increase in preterm birth rates in Puerto Rico cannot be explained by changes in known factors, and that there is sufficient evidence that exposure to some contaminants contributes to preterm birth. Contamination in Puerto Rico is extensive with more than 150 contaminated sites and a vast contamination of water resources. Of particular concern is the contamination in the north-coast karst aquifer. This aquifer provides important freshwater resources for human consumption. The same characteristics that make karst aquifers highly productive make them highly vulnerable to contamination and impart an enormous capacity to store and convey contaminants from sources to potential exposures zones. As a result, there is an inherent risk of exposure to contamination thorough groundwater. This presentation will address work being conducted to: assess the extent of groundwater contamination in the north coast of Puerto Rico; evaluate potential relationship between exposure to contaminants and preterm birth; develop new technology for discovery, transport characterization, and green remediation of contaminants in karst aquifers.

  16. Boron and selenium contamination in south Texas groundwater.

    PubMed

    Hudak, Paul F

    2004-01-01

    Boron and selenium concentrations from 112 water wells in an irrigated agricultural region of south Texas were compiled, mapped, and statistically analyzed. Wells in the study area produce water from the Gulf Coast Aquifer System, comprising coastward sloping beds of clay, silt, sand, and gravel. Nearly 84 percent of boron observations exceeded the 600 ug/L advisory level for drinking water, 70% exceeded the 1250 ug/L level for sensitive crops, and 24% exceeded the 3750 ug/L level for tolerant crops. Additionally, 21% of selenium observations exceeded the 20 ug/L advisory level for irrigation water, and five percent surpassed the 50 ug/L standard for drinking water. Many wells with high boron concentrations also had high selenium concentrations, and several clusters of high concentrations were in irrigated parts of the study area. However, there was no association between selenium and well depth, and a direct rather than inverse association between boron and well depth. Progressively brackish water in downdip reaches of the aquifer largely controls observed boron patterns. Both irrigation practices and prevailing groundwater chemistry significantly influence selenium concentrations in the study area. PMID:15533007

  17. The role of retail fertilizer dealers in reducing groundwater contamination: A focus on educational needs

    SciTech Connect

    Williams, R.J.; Ransom, J.M.

    1989-06-01

    Retail fertilizer dealers are a critical link in the US agricultural production complex. They are positioned to have major impact on annual fertilizer and pesticide use decisions involving over 44 million tons of fertilizer materials and 470 million pounds of active ingredients of pesticides (USDA, 1989). These inputs are key targets in efforts to reduce agrichemical contamination of groundwater. The purpose of this paper is: to focus on the role of the fertilizer/agrichemical dealer in this effort, to discuss educational needs of the dealer in order to operate his own business in compliance with environmental regulations and, to point out the educational and motivational needs of the dealer in order to assist his farmer-customers to use agrichemicals in ways that will eliminate or reduce groundwater contamination from farming operations.

  18. Baseline risk assessment for groundwater contamination at the uranium mill tailings site near Monument Valley, Arizona. Draft

    SciTech Connect

    Not Available

    1993-09-01

    This baseline risk assessment evaluates potential impact to public health or the environment resulting from groundwater contamination at the former uranium mill processing site near Monument Valley, Arizona. The tailings and other contaminated material at this site are being relocated and stabilized in a disposal cell at Mexican Hat, Utah, through the US Department of Energy (DOE) Uranium Mill Tailings Remedial Action (UMTRA) Project. The tailings removal is planned for completion by spring 1994. After the tailings are removed, groundwater contamination at the site will continue to be evaluated. This risk assessment is the first document specific to this site for the Groundwater Project. It will be used to assist in determining what remedial action is needed for contaminated groundwater at the site.

  19. PILOT STUDIES OF IN-SITU BIO-TRANSFORMATION OF MERCURY-CONTAMINATED GROUNDWATER IN KAZAKHSTAN UTILIZING NATIVE BACTERIA

    EPA Science Inventory

    Several regions in the Republic of Kazakhstan and throughout the former USSR are contaminated with mercury resulting from industrial releases. Our studies directed towards determining the feasibility of developing a biological filter, which when placed into the path the groundwat...

  20. In-situ control of ground-water contaminants by microbiological processes. Final report

    SciTech Connect

    Cunningham, A.B.; Bouwer, E.J.; Characklis, W.G.

    1988-12-20

    Processes governing accumulation in porous media flow are discussed along with their relationship to biotransformation of organic contaminants in ground water. The rates of biofilm accumulation and biotransformation are strongly influenced by transport characteristics that affect the delivery rate of substrate and nutrients to the growing cells. The processes of subsurface mass transport, biotransformation, and biofilm accumulation are highly interrelated. The report demonstrates these interrelationships by discussing fundamental concepts and results from laboratory and field investigations related to analysis and mitigation of porous-media biofouling and biodegradation of organic ground-water contaminants.

  1. A procedure to design a Permeable Adsorptive Barrier (PAB) for contaminated groundwater remediation.

    PubMed

    Erto, A; Lancia, A; Bortone, I; Di Nardo, A; Di Natale, M; Musmarra, D

    2011-01-01

    A procedure to optimize the design of a Permeable Adsorptive Barrier (PAB) for the remediation of a contaminated aquifer is presented in this paper. A computer code, including different routines that describe the groundwater contaminant transport and the pollutant capture by adsorption in unsteady conditions over the barrier solid surface, has been developed. The complete characterization of the chemical-physical interactions between adsorbing solids and the contaminated water, required by the computer code, has been obtained by experimental measurements. A case study in which the procedure developed has been applied to a tetrachloroethylene (PCE)-contaminated aquifer near a solid waste landfill, in the district of Napoli (Italy), is also presented and the main dimensions of the barrier (length and width) have been evaluated. Model results show that PAB is effective for the remediation of a PCE-contaminated aquifer, since the concentration of PCE flowing out of the barrier is everywhere always lower than the concentration limit provided for in the Italian regulations on groundwater quality. PMID:20846781

  2. Lyne and McLachlan (1949): Influence of the First Publication on Groundwater Contamination by Trichloroethene

    Microsoft Academic Search

    Michael O. Rivett; Stanley Feenstra; Lewis Clark

    2006-01-01

    The historical context and influence of the world's first published case of trichloroethene (TCE) contamination of groundwater by Lyne and McLachlan (1949) in The Analyst is established. Archive data and literature review, local reconnaissance, and consultation with relevant professionals were undertaken. Lyne and McLachlan were public analysts, officials authorized to provide certified (chemical) analysis, responsible for several United Kingdom (U.K.)

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  4. Paleocollapse structure as a passageway for groundwater flow and contaminant transport

    Microsoft Academic Search

    Wan Fang Zhou

    1997-01-01

    Paleocollapse structure is a rock collapse, resulting from the failure in the geological history of the bedrock overlying\\u000a karstified limestone. Depending on the present hydrogeological conditions within the area of paleocollapse and the internal\\u000a properties of these structures, they can provide a means to facilitate groundwater flow and contaminant transport. Inactive\\u000a paleocollapse structures can be reactivated by human activities such

  5. Assessing the vulnerability of a karst groundwater system to contamination by pharmaceuticals

    NASA Astrophysics Data System (ADS)

    Einsiedl, Florian; Radke, Michael

    2010-05-01

    Contamination of drinking water supplies is a serious problem and a potential threat to public health. Organic micropollutants such as pharmaceuticals and personal care products are identified as an environmental risk and concern has been raised about their environmental presence and fate. These compounds are present in effluents of wastewater treatment plants (WWTPs) in concentrations of up to several µg/L, and they have frequently been detected in surface waters and groundwater systems. A popular method for wastewater disposal in karst areas is the injection of wastewater into open sinkholes. Subsequently, the wastewater infiltrates rapidly along conduits and through the fractured karst aquifer. This is a major contributing factor to the contamination of karst aquifers. To address the vulnerability of such systems against relatively mobile organic micropollutants, we investigated the occurrence of two pharmaceuticals (diclofenac, ibuprofen) in combination with the groundwater heterogeneity and flow pathways in the aquifer. Groundwater samples and effluents of three WWTPs were repeatedly collected during a field campaign in the Franconian Alb karst system which is located in southern Germany. These results were coupled with hydrogeological investigations such as tracer tests, application of environmental isotopes (3H), and modeling. The results of this study demonstrated that (i) both pharmaceuticals are mobile in the karst aquifer and thus represent a risk for contamination of karst water, (ii) the transport of pharmaceuticals in the fractured system with mean transit times of some years affects the karst groundwater contamination, and (iii) long-term wastewater injection containing organic micropollutants into karst ecosystems may contribute to water quality deterioration over years.

  6. TIME-DEPENDENT HEALTH RISK FROM CONTAMINATED GROUNDWATER INCLUDING USE OF RELIABILITY, RESILIENCE, AND VULNERABILITY AS MEASURES1

    E-print Network

    Bolster, Diogo

    -Dependent Health Risk from Contami- nated Groundwater Including Use of Reliability, Resilience, and VulnerabilityTIME-DEPENDENT HEALTH RISK FROM CONTAMINATED GROUNDWATER INCLUDING USE OF RELIABILITY, RESILIENCE, AND VULNERABILITY AS MEASURES1 Carolyn Rodak, Stephen E. Silliman, and Diogo Bolster2 ABSTRACT: Traditionally

  7. Assessing the impact of VOC-contaminated groundwater on surface water at the city scale.

    PubMed

    Ellis, Paul A; Rivett, Michael O

    2007-04-01

    This study is believed to be one of the first to assess the impact of urban VOC-(volatile organic compound) contaminated groundwater on river-water quality at the city scale. A network of riverbed piezometers was used to study the 7.4-km urbanised reach of the River Tame that flows across the groundwater-effluent unconfined Triassic sandstone aquifer underlying the city of Birmingham (UK). Aquifer groundwater contained significant chlorinated VOC contamination due to the city's industrial heritage. Chlorinated VOC-contaminated baseflow was widespread along the reach with trichloroethene (TCE) dominant. VOC concentrations in riverbed piezometers were in the range 0.1-100 microg/l with typical regulatory limits occasionally exceeded by an order of magnitude. Although anaerobic biodegradation products such as cis-dichloroethene were widespread, they were unlikely to have formed in the generally aerobic riverbed. The lack of anaerobic conditions was ascribed to insufficient accumulation of low-permeability, organic-carbon rich riverbed sediments in this medium-high energy river. Assumptions a priori that natural attenuation of chlorinated VOCs will occur via reductive dechlorination in urban riverbeds are likely in error, particularly where deposits of medium-high permeability exist transmitting much of the baseflow. Surface-water quality impacts were nevertheless still low with in-river TCE increasing by just 2 microg/l over the 7.4-km reach. Agreement of baseflow contaminant flux estimates based on five flow-concentration product methods was achieved to within an order of magnitude with 22-200 kg/yr of TCE estimated to discharge to the 7.4-km reach (equivalent to 0.8-7.5 mg/d/m2 of riverbed). Such uncertainty was not regarded as unreasonable when the large measurement scale and geological and chemical heterogeneities are considered. Improved flux estimation methods and greater monitoring densities are nevertheless warranted. Considering Birmingham's long industrial history and known incidence of VOC-contaminated groundwater, the city-scale impact of VOC-contaminated groundwater upon surface-water quality was judged to be relatively modest. PMID:17182150

  8. HEALTH RISK ASSESSMENT ON RESIDENTS EXPOSED TO CHLORINATED HYDROCARBONS CONTAMINATED IN GROUNDWATER OF A HAZARDOUS WASTE SITE

    Microsoft Academic Search

    Lukas Jyuhn-Hsiarn Lee; Chang-Chuan Chan; Chih-Wen Chung; Yee-Chung Ma; Gan-Shuh Wang; Jung-Der Wang

    2002-01-01

    We conducted this study to estimate residents' chronic hazard and carcinogenic risk in a groundwater-contaminated community after on-site remediation in Taiwan during 1999-2000. We followed guidelines for assessing hazardous waste sites of the U.S. Environmental Protection Agency (EPA) and used empirically measured contaminant levels and exposure parameters to perform health risk assessment on seven chlorinated hydrocarbons. We measured groundwater concentrations

  9. The prediction of the effectiveness of interceptor trenches in the remediation of ground-water contamination by petroleum hydrocarbons 

    E-print Network

    Mast, Mary Katherine

    1991-01-01

    THE PREDICTION OF THE EFFECTIVENESS OF INTERCEPTOR TRENCHES IN THE REMEDIATION OF GROUND-WATER CONTAMINATION BY PETROLEUM HYDROCARBONS A Thesis by MARY KATHERINE MAST Submitted to the Office of Graduate Studies Texas A@M University... in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1991 Major Subject: Geology THE PREDICTION OF THE EFFECTIVENESS OF INTERCEPTOR TRENCHES IN THE REMEDIATION OF GROUND-WATER CONTAMINATION BY PETROLEUM HYDROCARBONS A...

  10. High Energy Electron Injection (E-Beam) Technology for the 'Ex-Situ' Treatment of MtBE-Contaminated Groundwater

    NASA Astrophysics Data System (ADS)

    Venosa, A. D.

    2002-09-01

    This Innovative Technology Evaluation Report documents the results of a demonstration of the high-energy electron injection (E-Beam) technology in application to groundwater contaminated with methyl t-butyl ether (MtBE) and with benzene, toluene, ethylbenzene, and xylenes (BTEX). The E-beam technology destroys organic contaminants in groundwater through irradiation with a beam of high-energy electrons. The demonstration was conducted at the Naval Base Ventura County (NBVC) in Port Hueneme, California.

  11. An inverse analytical technique applied to a chloride contamination of groundwater at Indian School and Levering sites, Michigan 

    E-print Network

    Shumway, Helen

    1992-01-01

    fulfillment of the requirements for the degree of MASTER OF SCIFNCE Decanter "99" Major Subject: Geology AN INVERSE ANALYTICAL TECHNIQUE APPLIED TO A CHLORIDE CONTAMINATION OF GROUNDWATER AT INDIAN SCHOOL AND LEVERING SITES, MICHIGAN A Thesis... to a Chloride Contamination of Groundwater at Indian School and Levering Sites, Michigan. (December 1992l Helen Shumway, B. S. , Texas A&M University Chair of Advisory Committee: Dr. patrick A. Domenico Two locations in Michigan, the Levering Site...

  12. Mechanisms for groundwater contamination by UCG: preliminary conclusions from the Hoe Creek study

    SciTech Connect

    Wang, F.T.; Mead, S.W.; Stuermer, D.H.

    1982-08-03

    We have monitored groundwater quality changes in approximately 60 wells constructed near the 3 underground coal gasification (UCG) experiments carried out at our Hoe Creek site in northeastern Wyoming. A broad range of residual gasification products are introduced into the groundwater system as a result of the UCG process. These groundwater contaminants may be of environmental significance if they find their way, in sufficient concentrations, into surface waters or aquifers from which water is extracted for drinking or agricultural purposes. In seeking to identify effective control technologies or mitigation measures, we have found it important to investigate the mechanisms responsible for the formation and dispersal of the contaminants. For example, an important mechanism for the production of organic contaminants may be pyrolysis reactions along the surfaces of cracks through which hot product gases escape from the cavity during gasification. As gasification continues, these pyrolysis products will be distilled further out in the surrounding coal and deposited on the coal surfaces. Other mechanisms that are believed to be important are post-burn pyrolysis as a result of residual cavity heat and the liberation of minerals from the coal by the action of dissolved CO/sub 2/.

  13. Impacts of antropogenic contaminants on vegetation and groundwater chemistry in a fen complex (IL)

    SciTech Connect

    Nuzzo, V.A.; Hensel, B.; Panno, S.; Cartwright, K.; Krapac, I. (Native Lanscapes, Rockford, IL (United States) Illinois State Geological Survey, Champaign (United States))

    1993-06-01

    Residential development within the watershed of a fen complex has resulted in encroachment of ground-water borne anthropogenic contaminants into 3 high quality fens. Groundwater samples were collected from peat and marl and analyzed for inorganic constituents. Height and density of Typha angustifolia L. and Scirpus acutus Muhl. were recorded in belt transects coincident with ground-water samples. Contaminant plumes from septic systems of houses near the fens had higher Na, Cl, NO[sub 3], and TDS levels than uncontaminated areas of the fens. Typha density increased significantly as Na, Cl, CL/SO[sub 4], and TDS levels increased; Scirpus occurred only where pH [ge] 7.1 (X[sub 2]=11.656, sl=.02). Scirpus density was generally independent of other water chemistry levels. In one fen Scirpus density declined significantly as Typha density increased (r[sub 2]=25.86). Contamination appears to favor Tvpha invasion, which subsequently leads to displacement of Scirpus.

  14. Application of preparative capillary gas chromatography (pcGC), automated structure generation and mutagenicity prediction to improve effect-directed analysis of genotoxicants in a contaminated groundwater

    Microsoft Academic Search

    Cornelia Meinert; Emma Schymanski; Eberhard Küster; Ralph Kühne; Gerrit Schüürmann; Werner Brack

    2010-01-01

    Background, aim and scope  The importance of groundwater for human life cannot be overemphasised. Besides fulfilling essential ecological functions,\\u000a it is a major source of drinking water. However, in the industrial area of Bitterfeld, it is contaminated with a multitude\\u000a of harmful chemicals, including genotoxicants. Therefore, recently developed methodologies including preparative capillary\\u000a gas chromatography (pcGC), MOLGEN-MS structure generation and mutagenicity prediction

  15. California GAMA Program: Sources and transport of nitrate in shallow groundwater in the Llagas Basin of Santa Clara County, California

    SciTech Connect

    Moran, J E; McNab, W; Esser, B; Hudson, G; Carle, S; Beller, H; Kane, S; Tompson, A B; Letain, T; Moore, K; Eaton, G; Leif, R; Moody-Bartel, C; Singleton, M

    2005-06-29

    A critical component of the State Water Resource Control Board's Groundwater Ambient Monitoring and Assessment (GAMA) Program is to assess the major threats to groundwater resources that supply drinking water to Californians (Belitz et al., 2004). Nitrate is the most pervasive and intractable contaminant in California groundwater and is the focus of special studies under the GAMA program. This report presents results of a study of nitrate contamination in the aquifer beneath the cities of Morgan Hill and Gilroy, CA, in the Llagas Subbasin of Santa Clara County, where high nitrate levels affect several hundred private domestic wells. The main objectives of the study are: (1) to identify the main source(s) of nitrate that issue a flux to the shallow regional aquifer (2) to determine whether denitrification plays a role in the fate of nitrate in the subbasin and (3) to assess the impact that a nitrate management plan implemented by the local water agency has had on the flux of nitrate to the regional aquifer. Analyses of 56 well water samples for major anions and cations, nitrogen and oxygen isotopes of nitrate, dissolved excess nitrogen, tritium and groundwater age, and trace organic compounds, show that synthetic fertilizer is the most likely source of nitrate in highly contaminated wells, and that denitrification is not a significant process in the fate of nitrate in the subbasin except in the area of recycled water application. In addition to identifying contaminant sources, these methods offer a deeper understanding of how the severity and extent of contamination are affected by hydrogeology and groundwater management practices. In the Llagas subbasin, the nitrate problem is amplified in the shallow aquifer because it is highly vulnerable with high vertical recharge rates and rapid lateral transport, but the deeper aquifers are relatively more protected by laterally extensive aquitards. Artificial recharge delivers low-nitrate water and provides a means of long-term remediation. Examination of nitrate concentration in relation to groundwater age indicates that the nitrate management plan has not yet resulted in a decrease in the flux of nitrate to the shallow aquifer in the areas tested.

  16. Preliminary evaluation of ground-water contamination by coal-tar derivatives, St. Louis Park area, Minnesota

    USGS Publications Warehouse

    Hult, Marc F.; Schoenberg, Michael

    1981-01-01

    Operation of a coal-tar distillation and wood preserving plant for 1918-72 in St. Louis Park, Minnesota, resulted in ground-water contamination. This report presents the results of the first year (1979) of an ongoing study. By 1932, water in the Prairie du Chien-Jordan aquifer, the region 's major source of ground water, was contaminated 3,500 feet from the plant. The hydraulic characteristics of the Prairie du Chien-Jordan aquifer , its long contamination history, and fluctuating pumpage combine to creat a complex distribution of coal-tar derivatives observed in the aquifer. The Prairie du Chien-Jordan aquifer underlies the area at depths of 250 to 500 feet and is overlain by two bedrock aquifers (Platteville and St. Peter), two confining beds (Glenwood and basal part of St. Peter), and 70 to 100 feet of glacial drift. Multiaquifer wells in the area have permitted contaminated water from near-surface aquifers to flow downward into the Prairie du Chien-Jordan aquifer. Flow rates of 20 to 150 gallons per minute from the shallower aquifers into the Prairie du Chien-Jordan aquifer were observed in five wells. In the drift, a hydrocarbon fluid phase is moving vertically downward relative to the aqueous phase. Dissolved constituents in the drift and Platteville aquifer, the uppermost bedrock unit over most of the area, have moved at least 4,000 feet. Low-molecular-weight compounds are moving preferentially through the drift and Platteville aquifer system. (USGS)

  17. Source, type and extent of inorganic contamination within the Birmingham urban aquifer system, UK

    NASA Astrophysics Data System (ADS)

    Ford, M.; Tellam, J. H.

    1994-04-01

    A survey of the inorganic quality of the groundwater of the Birmingham Triassic sandstone aquifer was carried out by sampling seventy 80-150 m deep industrial abstraction boreholes, 11 shallow monitoring piezometers, two submerged tunnels and two flooded industrial basements, and a set of trial pits. Borehole logging and historical data were also obtained. Given that the city of Birmingham is as long established as most industrial conurbations in the world, the degree of groundwater inorganic contamination as indicated by abstraction well samples is not excessive. Out of the 28 determinands measured, only NO -3 and Ba 2+ consistently approach and exceed their European Community Maximum Admissible Concentrations standards for drinking water and the barium is being supplied by the aquifer rather than having an anthropogenic source. However, a few abstraction boreholes have highly contaminated groundwaters, with for example milligram per litre levels of heavy metals. In addition, there is a correlation between land use and chemistry, with the highest salinity, sulphate, chloride, sodium, boron, and total heavy metal concentrations being associated with metal-working sites. High concentrations of heavy metals (and NH +4 are unexpected in the near-neutral pH Triassic sandstone groundwaters given the high sorption capacity of the sandstone: it is concluded that one reason for the occasionally high concentrations observed is the presence of very locialized high concentration recharge. Data from shallow piezometers confirm the considerable degree of heterogeneity in groundwater quality on a small scale — the pollution is mainly from point sources. Sampling from piezometers, tunnels, and basements demonstrates that the groundwater concentrations at shallow depths are often much higher than the pumped water analyses suggest. However, nitrate groundwaters appear to vary much less with depth than other species, reflecting a longer history of supply and a wider range of sources. Geophysical logging and sampling of well columns, and other observations indicate that the intermittent pumping of abstraction wells results in the pumped water quality being biased towards the shallower, high concentrations groundwaters rather than being a uniform mixture from all screened depths. Historical data show various trends, and these can be related to local hydrogeology, land use, and abstraction history. Comparisons of organic and inorganic pollution show that distributions are very different, reflecting differences in physical transport processes, chemical interactions, and histories of chemical usage.

  18. 3-D Seismic Tomography Survey at a Groundwater Contamination Site

    NASA Astrophysics Data System (ADS)

    Azaria, A.; Zelt, C.; Levander, A.

    2002-12-01

    As part of an ongoing environmental characterization project at Hill Air Force Base near Ogden, Utah, a 3-D seismic survey led by a team from Rice University was performed over a contaminated aquifer in 2000. This site contains significant amounts of dense non-aqueous phase liquids (DNAPLs) in a shallow aquifer less than ~15 m deep. The aquifer is bounded below by a clay aquiclude, in which a paleochannel acts as a trap for the contaminants. The overburden consists of Quaternary sands, gravels and clays. Imaging the structure of the paleochannel at depths up to 15 m is the main target of the survey. The four week experiment included 3-D reflection, 3-D refraction, checkshot surveys and vertical seismic profiles using wells up to 15m deep. Here we present traveltime tomography results from the 3-D refraction survey which consisted of 596 RefTek Texan recorders deployed uniformly in a stationary rectangular grid over an area of 95m by 36m. A shot from a .223 caliber rifle was fired 30cm from each receiver station, yielding a dataset with about 360,000 traces. The arrival times of the refracted waves were used in a 3-D tomographic inversion to image the seismic velocity structure of the study area. The iterative, nonlinear tomographic approach employs regularization to smooth the model perturbations with respect to a simple 1-D starting/reference model. The resulting velocity model shows that the near-surface velocity increases by roughly a factor of 5 in the upper 15m, from about 300m/s to 1500m/s. Cross-sections through the model show a north-south trending low-velocity feature interpreted to be the channel structure. The low-velocity feature is best viewed via depth slices which define an anomaly that roughly outlines the geometry of the buried paleo-channel based on well data. A comparison between the 3-D velocity model and time slices through a brute stack of the 3-D reflection data also show close agreement (see Dana et al. this session). Checkerboard tests applied to the velocity model establishes a 7.5m lateral resolution throughout most of the depth range of interest. While the long wavelength features of the model reveal the paleo-channel, the velocity model is likely a broad and smooth characterization of the true velocity structure.

  19. Evaluation of several biological monitoring techniques for hazard assessment of potentially contaminated wastewater and groundwater. Volume 3. Old O-field groundwater. Final report, July 1990-December 1991

    SciTech Connect

    Burton, D.T.; Turley, S.D.

    1992-03-01

    The toxicity of contaminated Old O-Field (Edgewood Area of Aberdeen Proving Ground) groundwater and the reduction and/or elimination of toxicity by various treatment processes were evaluated. The study was divided into a bench scale and pilot scale study. The bench scale studies consisted of 48-h definitive acute toxicity tests run with daphnid neonates (Daphnia magna) and juvenile fathead minnows (Pimephales promelas) exposed to untreated Old O-Field groundwater and groundwater treated by metals precipitation, UV oxidation (H 2O2 ), carbon adsorption, and carbon adsorption/biological sludge. The pilot scale studies consisted of several 96-h definitive acute toxicity tests run with two freshwater and two saltwater invertebrates and fish and Ames mutagenicity assays. Acute toxicity tests were run on untreated Old O-Field groundwater and groundwater treated by metals precipitation, UV oxidation (H2O2), air stripping, and carbon adsorption during the pilot scale study. The freshwater invertebrate and fish used in the study were daphnid neonates and juvenile fathead minnows, respectively. The saltwater invertebrate and fish were juvenile mysids (Mysidopsis bahia) and juvenile sheepshead minnows (Cyprinodon variegatus). Ames tests were run on untreated groundwater, UV oxidation-treated groundwater, and carbon-treated groundwater.... Groundwater, Aquatic, Toxicity, Daphnia, Daphnia magna, Fathead minnow, Pimephales promelas, Mysid, Mysidopsis bahia, Sheepshead minnow, Cyprinodon variegatus.

  20. Assessing TNT and DNT groundwater contamination by compound-specific isotope analysis and 3H– 3He groundwater dating: A case study in Portugal

    Microsoft Academic Search

    Helena I. F. Amaral; Judite Fernandes; Michael Berg; René P. Schwarzenbach; Rolf Kipfer

    2009-01-01

    Trinitrotoluene (TNT) and dinitrotoluene (DNT) originating from 50years of explosives production have heavily contaminated two stacked aquifers in the vicinity of Lisboa, Portugal. To assess if these poly-nitroaromatic compounds (P-NACs) are being degraded in the subsurface, tracer-based groundwater dating techniques combined with compound-specific isotope analyses (CSIA) were applied.The groundwater residence times were distinctly different in the two aerobic aquifers, as

  1. A new method for stable carbon isotope analysis of chlorofluorocarbons in contaminated groundwater

    NASA Astrophysics Data System (ADS)

    Horst, Axel; Lacrampe-Couloume, Georges; Sherwood Lollar, Barbara

    2015-04-01

    Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) have been widely used as refrigerants, propellants, solvents, foaming agents and are important intermediates in the production of anesthetics and other fluorinated compounds. Due to their ozone depletion potential, production was banned for most uses under the Montreal Protocol (1987) and its amendments and atmospheric mixing ratios have started to decrease. In addition to the atmosphere, CFCs and HCFCs have been detected in groundwater, and emissions from various sources such as landfill sites are still ongoing. Previous studies have shown that both abiotic and biotic transformation of CFCs may occur under certain conditions. To investigate degradation that may take place in soils and groundwaters, a purge and trap method (P&T) has been developed to measure the stable carbon isotopic composition of CFCs and HCFCs extracted from waters. A set of pure phase working standards (HCFC-22, CFC-11, CFC-113) has been prepared offline and characterized by sealed tube combustion dual inlet mass spectrometry. Comparison between isotopic standards and CFCs extracted by our method demonstrates the sample P&T extraction steps do not induce significant ?13C fractionation (lt;0.5 per mill). Standards characterized by continuous flow CSIA (compound specific isotope analysis) after extraction agree with offline characterized values. Evaporation experiments were carried out to investigate any isotope effects due to volatile loss that might occur either due to sampling methods or sample handling in the lab. Monitoring ?13C values during progressive evaporation showed small isotopic fractionation associated with evaporation. Enrichment factors, obtained from Rayleigh plots, showed inverse isotope fractionation i.e depletion in 13C in the remaining compound. Notably, this effect is in the opposite direction to the fractionation (13C enrichment) that is likely to be associated with abiotic or biotic transformation effects. This bodes well for the use of CSIA to identify and monitor transformation in the field as any isotopic effects due to volatile loss would only result in a conservative estimate of transformation but not confuse the degradation signal. As a result, enrichment factors in field samples might be underestimated and lead to a more conservative estimate of degradation at contaminated sites. CFCs from several suppliers were characterized to investigate ?13C variation between sources and between different CFC compounds. Significant differences were observed between all measured compounds. However for each compound, ?13C values determined in this study were similar to ranges reported previously for other pure phase CFCs - suggesting a consistent range of source signatures may exist for each compound. As a last step of method evaluation, water samples from a contaminated industrial site were measured. This first preliminary field data will be discussed in comparison to pure phase compounds and with respect to potential degradation.

  2. Agriculture's Contribution to Nitrate Contamination of Californian Groundwater (1945-2005).

    PubMed

    Rosenstock, Todd S; Liptzin, Daniel; Dzurella, Kristin; Fryjoff-Hung, Anna; Hollander, Allan; Jensen, Vivian; King, Aaron; Kourakos, George; McNally, Alison; Pettygrove, G Stuart; Quinn, Jim; Viers, Joshua H; Tomich, Thomas P; Harter, Thomas

    2014-05-01

    Nitrogen (N) use in intensive agriculture can degrade groundwater resources. However, considerable time lags between groundwater recharge and extraction complicate source attribution and remedial responses. We construct a historic N mass balance of two agricultural regions of California to understand trends and drivers of past and present N loading to groundwater (1945-2005). Changes in groundwater N loading result from historic changes in three factors: the extent of agriculture (cropland area and livestock herd increased 120 and 800%, respectively), the intensity of agriculture (synthetic and manure waste effluent N input rates increased by 525 and 1500%, respectively), and the efficiency of agriculture (crop and milk production per unit of N input increased by 25 and 19%, respectively). The net consequence has been a greater-than-order-of-magnitude increase in nitrate (NO) loading over the time period, with 163 Gg N yr now being leached to groundwater from approximately 1.3 million ha of farmland (not including alfalfa [ L.]). Meeting safe drinking water standards would require NO leaching reductions of over 70% from current levels through reductions in excess manure applications, which accounts for nearly half of all groundwater N loading, and through synthetic N management improvements. This represents a broad challenge given current economic and technical conditions of California farming if farm productivity is to be maintained. The findings illustrate the growing tension-characteristic of agricultural regions globally-between intensifying food, feed, fiber, and biofuel production and preserving clean water. PMID:25602818

  3. [Variation Characteristics and Sources of Heavy Metals in an Urban Karst Groundwater System during Rainfall Event].

    PubMed

    Ren, Kun; Yang, Ping-heng; Jiang, Ze-li; Wang, Zun-bo; Shi, Yang; Wang, Feng-kang; Li, Xiao-chun

    2015-04-01

    The groundwater discharge and heavy metal concentrations (Mn, Pb, Cu and As) at the outlet of Nanshan Laolongdong karst subterranean river, located at the urban region in Chongqing, were observed during the rainfall events. Analysis of flow and concentrations curves was employed to study their responses to the rainfall events and explore the internal structure of karst hydrological system. Principal component analysis (PCA) and measurements were used to identify the sources of heavy metals during rainfall. The result showed that the discharge and concentrations of the heavy metals responded promptly to the rainfall event. The variation characteristics of flow indicated that Laolongdong subterranean river system belonged to a karst hydrological system including fractures together with conduits. Urban surface runoff containing large amounts of Mn, Pb and Cu went directly to subterranean river via sinkholes, shafts and karst windows. As a result, the peak concentrations of contaminants (Mn, Pb and Cu) flowed faster than those of discharge. The major sources of water pollution were derived from urban surface runoff, soil and water loss. Cave dripwater and rainwater could also bring a certain amount of Mn, Pb and As into the subterranean river. Urban construction in karst areas needs scientific and rational design, perfect facilities and well-educated population to prevent groundwater pollution from the source. PMID:26164900

  4. GROUNDWATER QUALITY MONITORING OF WESTERN COAL STRIP MINING: PRELIMINARY DESIGNS FOR ACTIVE MINE SOURCES OF POLLUTION

    EPA Science Inventory

    Three potential pollution source categories have been identified for Western coal strip mines. These sources include mine stockpiles, mine waters, and miscellaneous active mine sources. TEMPO's stepwise monitoring methodology (Todd et al., 1976) is used to develop groundwater qua...

  5. An application of supported liquid membranes for removal of inorganic contaminants from groundwater

    SciTech Connect

    Chiarizia, R. (Argonne National Lab., IL (United States) Westinghouse Hanford Co., Richland, WA (United States)); Horwitz, E.P. (Argonne National Lab., IL (United States)); Hodgson, K.M. (Westinghouse Hanford Co., Richland, WA (United States))

    1991-01-01

    This review paper summarizes the results of an investigation on teh use of supported liquid membranes for the removal of uranium (VI) and some anionic contaminants (technetium(VII), chromium(VI) and nitrates) from the Hanford site groundwater. As a membrane carrier for U(VI), bis(2,4,4-trimethylpentyl)phosphinic acid was selected because of its high selectivity over calcium and magnesium. The water soluble complexing agent 1-hydroxyethane-1,1-diphosphonic acid was used as stripping agent. For the anionic contaminants the long-chain aliphatic amines Primene JM-T (primary)., Amberlite LA-1 (secondary) and trilaurylamine (tertiary) were investigated as membrane carriers. Among these amines, Amberlite LA-2 proved to be the most effective carrier for the simultaneous removal of the investigated anion contaminants. A good long-term stability (at least one month) of the liquid membranes was obtained, especially in the uranium(VI) removal. 8 refs., 4 figs., 4 tabs.

  6. An application of supported liquid membranes for removal of inorganic contaminants from groundwater

    SciTech Connect

    Chiarizia, R. [Argonne National Lab., IL (United States); [Westinghouse Hanford Co., Richland, WA (United States); Horwitz, E.P. [Argonne National Lab., IL (United States); Hodgson, K.M. [Westinghouse Hanford Co., Richland, WA (United States)

    1991-12-31

    This review paper summarizes the results of an investigation on teh use of supported liquid membranes for the removal of uranium (VI) and some anionic contaminants (technetium(VII), chromium(VI) and nitrates) from the Hanford site groundwater. As a membrane carrier for U(VI), bis(2,4,4-trimethylpentyl)phosphinic acid was selected because of its high selectivity over calcium and magnesium. The water soluble complexing agent 1-hydroxyethane-1,1-diphosphonic acid was used as stripping agent. For the anionic contaminants the long-chain aliphatic amines Primene JM-T (primary)., Amberlite LA-1 (secondary) and trilaurylamine (tertiary) were investigated as membrane carriers. Among these amines, Amberlite LA-2 proved to be the most effective carrier for the simultaneous removal of the investigated anion contaminants. A good long-term stability (at least one month) of the liquid membranes was obtained, especially in the uranium(VI) removal. 8 refs., 4 figs., 4 tabs.

  7. Groundwater ecosystem resilience to organic contaminations: microbial and geochemical dynamics throughout the 5-year life cycle of a surrogate ethanol blend fuel plume.

    PubMed

    Ma, Jie; Nossa, Carlos W; Alvarez, Pedro J J

    2015-09-01

    The capacity of groundwater ecosystem to recover from contamination by organic chemicals is a vital concern for environmental scientists. A pilot-scale aquifer system was used to investigate the long-term dynamics of contaminants, groundwater geochemistry, and microbial community structure (by 16S rRNA gene pyrosequencing and quantitative real-time PCR) throughout the 5-year life cycle of a surrogate ethanol blend fuel plume (10% ethanol + 50 mg/L benzene + 50 mg/L toluene). Two-year continuous ethanol-blended release significantly changed the groundwater geochemistry (resulted in anaerobic, low pH, and organotrophic conditions) and increased bacterial and archaeal populations by 82- and 314-fold respectively. Various anaerobic heterotrophs (fermenters, acetogens, methanogens, and hydrocarbon degraders) were enriched. Two years after the release was shut off, all contaminants and their degradation byproducts disappeared and groundwater geochemistry completely restored to the pre-release states (aerobic, neutral pH, and oligotrophic). Bacterial and archaeal populations declined by 18- and 45-fold respectively (relative to the time of shut off). Microbial community structure reverted towards the pre-release states and alpha diversity indices rebounded, suggesting the resilience of microbial community to ethanol blend releases. We also found shifts from O2-sensitive methanogens (e.g., Methanobacterium) to methanogens that are not so sensitive to O2 (e.g., Methanosarcina and Methanocella), which is likely to contribute to the persistence of methanogens and methane generation following the source removal. Overall, the rapid disappearance of contaminants and their metabolites, rebound of geochemical footprints, and resilience of microbial community unequivocally document the natural capacity of groundwater ecosystem to attenuate and recover from a large volume of catastrophic spill of ethanol-based biofuel. PMID:25996759

  8. TECHNICAL BASIS FOR EVALUATING SURFACE BARRIERS TO PROTECT GROUNDWATER FROM DEEP VADOSE ZONE CONTAMINATION

    SciTech Connect

    FAYER JM; FREEDMAN VL; WARD AL; CHRONISTER GB

    2010-02-24

    The U.S. DOE and its predecessors released nearly 2 trillion liters (450 billion gallons) of contaminated liquid into the vadose zone at the Hanford Site. Some of the contaminants currently reside in the deeper parts of the vadose zone where they are much less accessible to characterization, monitoring, and typical remediation activities. The DOE Richland Operations Office (DOE-RL) prepared a treatability test plan in 2008 to examine remediation options for addressing contaminants in the deep vadose zone; one of the technologies identified was surface barriers (also known as engineered barriers, covers, and caps). In the typical configuration, the contaminants are located relatively close to the surface, generally within 15 m, and thus they are close to the base of the surface barrier. The proximity of the surface barrier under these conditions yielded few concerns about the effectiveness of the barrier at depth, particularly for cases in which the contaminants were in a lined facility. At Hanford, however, some unlined sites have contaminants located well below depths of 15 m. The issue raised about these sites is the degree of effectiveness of a surface barrier in isolating contaminants in the deep vadose zone. Previous studies by Hanford Site and PNNL researchers suggest that surface barriers have the potential to provide a significant degree of isolation of deep vadose zone contaminants. The studies show that the actual degree of isolation is site-specific and depends on many factors, including recharge rates, barrier size, depth of contaminants, geohydrologic properties ofthe sediments, and the geochemical interactions between the contaminants and the sediments. After the DOE-RL treatability test plan was published, Pacific Northwest National Laboratory was contracted to review the information available to support surface barrier evaluation for the deep vadose zone, identify gaps in the information and outcomes necessary to fill the data gaps, and outline tasks to achieve those outcomes. Full understanding of contaminant behavior in the deep vadose zone is constrained by four key data gaps: limited access; limited data; limited time; and the lack of an accepted predictive capability for determining whether surface barriers can effectively isolate deep vadose zone contaminants. Activities designed to fill these data gaps need to have these outcomes: (1) common evaluation methodology that provides a clear, consistent, and defensible basis for evaluating groundwater impacts caused by placement of a surface barrier above deep vadose zone contamination; (2) deep vadose zone data that characterize the lithology, the spatial distribution of moisture and contaminants, the physical, chemical, and biological process that affect the mobility of each contaminant, and the impacts to the contaminants following placement of a surface barrier; (3) subsurface monitoring to provide subsurface characterization of initial conditions and changes that occur during and following remediation activities; and (4) field observations that span years to decades to validate the evaluation methodology. A set of six proposed tasks was identified to provide information needed to address the above outcomes. The proposed tasks are: (1) Evaluation Methodology - Develop common evaluation methodology that will provide a clear, consistent, and defensible basis for evaluating groundwater impacts caused by placement of a surface barrier above deep vadose zone contamination. (2) Case Studies - Conduct case studies to demonstrate the applicability ofthe common evaluation methodology and provide templates for subsequent use elsewhere. Three sites expected to have conditions that would yield valuable information and experience pertinent to deep vadose zone contamination were chosen to cover a range of conditions. The sites are BC Cribs and Trenches, U Plant Cribs, and the T Farm Interim Cover. (3) Subsurface Monitoring Technologies - Evaluate minimally invasive geophysical approaches for delineating subsurface plumes and monitoring their migration in the deep

  9. Fate of sulfamethoxazole, 4-nonylphenol, and 17?-estradiol in groundwater contaminated by wastewater treatment plant effluent

    USGS Publications Warehouse

    Barber, Larry B.; Keefe, Steffanie H.; LeBlanc, Denis R.; Bradley, Paul M.; Chapelle, Francis H.; Meyer, Michael T.; Loftin, Keith A.; Koplin, Dana W.; Rubio, Fernando

    2009-01-01

    Organic wastewater contaminants (OWCs) were measured in samples collected from monitoring wells located along a 4.5-km transect of a plume of groundwater contaminated by 60 years of continuous rapid infiltration disposal of wastewater treatment plant effluent. Fifteen percent of the 212 OWCs analyzed were detected, including the antibiotic sulfamethoxazole (SX), the nonionic surfactant degradation product 4-nonylphenol (NP), the solvent tetrachloroethene (PCE), and the disinfectant 1,4-dichlorobenzene (DCB). Comparison of the 2005 sampling results to data collected from the same wells in 1985 indicates that PCE and DCB are transported more rapidly in the aquifer than NP, consistent with predictions based on compound hydrophobicity. Natural gradient in situ tracer experiments were conducted to evaluate the subsurface behavior of SX, NP, and the female sex hormone 17?-estradiol (E2) in two oxic zones in the aquifer: (1) a downgradient transition zone at the interface between the contamination plume and the overlying uncontaminated groundwater and (2) a contaminated zone located beneath the infiltration beds, which have not been loaded for 10 years. In both zones, breakthrough curves for the conservative tracer bromide (Br?) and SX were nearly coincident, whereas NP and E2 were retarded relative to Br? and showed mass loss. Retardation was greater in the contaminated zone than in the transition zone. Attenuation of NP and E2 in the aquifer was attributed to biotransformation, and oxic laboratory microcosm experiments using sediments from the transition and contaminated zones show that uniform-ring-labeled 14C 4-normal-NP was biodegraded more rapidly (30?60% recovered as 14CO2 in 13 days) than 4-14C E2 (20?90% recovered as 14CO2in 54 days). There was little difference in mineralization potential between sites.

  10. BACTERIA USED TO PRECIPITATE MERCURY IN CONTAMINATED GROUNDWATER OF PAVLODAR, KAZAKHSTAN

    EPA Science Inventory

    Abstract for poster presentation: A number of regions in Kazakhstan are contaminated with soluble mercury originating from industrial sources. A chlor-alkali plant that operated from 1970-1990 caused contamination of ground water near a northern suburb of Pavlodar city. The plume...

  11. Field-based detection and monitoring of uranium in contaminated groundwater using two immunosensors

    SciTech Connect

    Melton, S.J.; Yu, H.; Williams, K.H.; Morris, S.A.; Long, P.E.; Blake, D.A.

    2009-05-01

    Field-based monitoring of environmental contaminants has long been a need for environmental scientists. Described herein are two kinetic exclusion-based immunosensors, a field portable sensor (FPS) and an inline senor, that were deployed at the Integrated Field Research Challenge Site of the U.S. Department of Energy in Rifle, CO. Both sensors utilized a monoclonal antibody that binds to a U(VI)-dicarboxyphenanthroline complex (DCP) in a kinetic exclusion immunoassay format. These sensors were able to monitor changes of uranium in groundwater samples from {approx} 1 {micro}M to below the regulated drinking water limit of 126 nM (30 ppb). The FPS is a battery-operated sensor platform that can determine the uranium level in a single sample in 5-10 min, if the instrument has been previously calibrated with standards. The average minimum detection level (MDL) in this assay was 0.33 nM (79 ppt), and the MDL in the sample (based on a 1:200?1:400 dilution) was 66?132 nM (15.7?31.4 ppb). The inline sensor, while requiring a grounded power source, has the ability to autonomously analyze multiple samples in a single experiment. The average MDL in this assay was 0.12 nM (29 ppt), and the MDL in the samples (based on 1:200 or 1:400 dilutions) was 24?48 nM (5.7?11.4 ppb). Both sensor platforms showed an acceptable level of agreement (r{sup 2} = 0.94 and 0.76, for the inline and FPS, respectively) with conventional methods for uranium quantification.

  12. Impact of cemeteries on groundwater contamination by bacteria and viruses - a review.

    PubMed

    ?ychowski, Józef; Bryndal, Tomasz

    2015-06-01

    In the process of decomposition of a human body, 0.4-0.6 litres of leachate is produced per 1 kg of body weight. The leachate contains pathogenic bacteria and viruses that may contaminate the groundwater and cause disease when it is used for drinking. So far, this topic has been investigated in several regions of the world (mainly Brazil, Australia, the Republic of South Africa, Portugal, the United Kingdom and Poland). However, recently more and more attention has been focused on this issue. This study reviews the results of investigations related to the impact of cemeteries on groundwater bacteriology and virology. This topic was mainly discussed in the context of the quantities and qualities of changes in types of microorganisms causing groundwater contamination. In some cases, these changes were related to the environmental setting of a place, where a cemetery was located. The review is completed by a list of recommendations. Their implementation aims to protect the local environment, employees of funeral homes and the residents living in the vicinity of cemeteries. In this form, this review aims to familiarize the reader with the results of this topic, and provide practical guidance for decision-makers in the context of expansion and management of cemeteries, as well as the location of new ones. PMID:26042963

  13. Simulation of phosphate transport in sewage-contaminated groundwater, Cape Cod, Massachusetts

    USGS Publications Warehouse

    Stollenwerk, K.G.

    1996-01-01

    Sewage-contaminated groundwater currently discharges to Ashumet Pond, located on Cape Cod, Massachusetts Phosphate concentrations as high as 60 ??mol l-1 have been measured in groundwater entering Ashumet Pond, and there is concern that the rate of eutrophication could increase. Phosphate in the sewage plume is sorbed by aquifer sediment; the amount is a function of phosphate concentration and pH. A nonelectrostatic surface-complexation model coupled with a one-dimensional solute-transport code was used to simulate sorption and desorption of phosphate in laboratory column experiments. The model simulated sorption of phosphate reasonably well, although the slow rate of approach to complete breakthrough indicated a nonequilibrium process that was not accounted for in the solute-transport model The rate of phosphate desorption in the column experiments was relatively slow Phosphate could still be measured in effluent after 160 pore volumes of uncontaminated groundwater had been flushed through the columns. Desorption was partly a function of the slowly decreasing pH in the columns and could be modeled quantitatively. Disposal of sewage at this site is scheduled to stop in 1995; however, a large reservoir of sorbed phosphate exists on aquifer sediment upgradient from Ashumet Pond. Computer simulations predict that desorption of phosphate could result in contamination of Ashumet Pond for decades.

  14. Inspection and monitoring plan, contaminated groundwater seeps 317/319/ENE Area, Argonne National Laboratory

    SciTech Connect

    NONE

    1996-10-11

    During the course of completing the Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) in the 317/319/East-Northeast (ENE) Area of Argonne National Laboratory-East (ANL-E), groundwater was discovered moving to the surface through a series of groundwater seeps. The seeps are located in a ravine approximately 600 ft south of the ANL-E fence line in Waterfall Glen Forest Preserve. Samples of the seep water were collected and analyzed for selected parameters. Two of the five seeps sampled were found to contain detectable levels of organic contaminants. Three chemical species were identified: chloroform (14--25 {micro}g/L), carbon tetrachloride (56--340 {micro}g/L), and tetrachloroethylene (3--6 {micro}g/L). The other seeps did not contain detectable levels of volatile organics. The nature of the contaminants in the seeps will also be monitored on a regular basis. Samples of surface water flowing through the bottom of the ravine and groundwater emanating from the seeps will be collected and analyzed for chemical and radioactive constituents. The results of the routine sampling will be compared with the concentrations used in the risk assessment. If the concentrations exceed those used in the risk assessment, the risk calculations will be revised by using the higher numbers. This revised analysis will determine if additional actions are warranted.

  15. Coupled Geochemical Impacts of Leaking CO2 and Contaminants from Subsurface Storage Reservoirs on Groundwater Quality.

    PubMed

    Shao, Hongbo; Qafoku, Nikolla P; Lawter, Amanda R; Bowden, Mark E; Brown, Christopher F

    2015-07-01

    The leakage of CO2 and the concomitant brine from deep storage reservoirs to overlying groundwater aquifers is considered one of the major potential risks associated with geologic CO2 sequestration (GCS). In this work both batch and column experiments were conducted to determine the fate of trace metals in groundwater in the scenarios of CO2 and metal-contaminated brine leakage. The sediments for this study were from an unconsolidated sand and gravel aquifer in Kansas, containing 0-4 wt % carbonates. Cd (114 ?g/L) and As (40 ?g/L) were spiked into the reaction system to represent potential contaminants from the reservoir brine. Through this research we demonstrated that Cd and As were adsorbed on the sediments, in spite of the lowered pH due to CO2 dissolution in the groundwater. Cd concentrations in the effluent were below the Cd MCL, even for sediments without detectable carbonate to buffer the pH. Arsenic concentrations in the effluent were also significantly lower than the influent concentration, suggesting that the sediments tested have the capacity to mitigate the coupled adverse effects of CO2 leakage and brine intrusion. The mitigation capacity of sediment is a function of its geochemical properties (e.g., the presence of carbonate minerals, adsorbed As, and phosphate). PMID:26039150

  16. Arsenic contamination of groundwater and prevalence of arsenical dermatosis in the Hetao plain area, Inner Mongolia, China

    Microsoft Academic Search

    Xiaojuan Guo; Yoshihisa Fujino; Satoshi Kaneko; Kegong Wu; Yajuan Xia; Takesumi Yoshimura

    2001-01-01

    An investigation was carried out on arsenic contamination of groundwater and prevalence of arsenical dermatosis in the Hetao plain of Inner Mongolia Autonomous Region, China. Based on the screening of water samples from 96 randomly selected wells in this Region, two areas (Wuyuan and Alashan) were chosen as highly contaminated areas because arsenic in the water samples was higher than

  17. Update on the aquifer/wetlands restoration project at Utica, Nebraska, with recommendations for remapping of the carbon tetrachloride contamination in groundwater.

    SciTech Connect

    LaFreniere, L. M.; Environmental Science Division

    2010-04-20

    In 1992-1993, Argonne National Laboratory investigated potential carbon tetrachloride contamination that might be linked to the former grain storage facility operated by the Commodity Credit Corporation (CCC) of the U.S. Department of Agriculture (USDA) at Utica, Nebraska. These initial studies identified carbon tetrachloride in a plume of contaminated groundwater, extending approximately 3,500 ft southeastward from the former CCC/USDA facility, within a shallow upper aquifer that had been used previously as a municipal water source by the town (Figure 1.1). A deeper aquifer used as the current municipal water source was found to be free of carbon tetrachloride contamination. Although the shallow aquifer was no longer being used as a source of drinking water at Utica, additional studies indicated that the carbon tetrachloride could pose an unacceptable health threat to potential future residents who might install private wells along the expected downgradient migration pathway of the plume. On the basis of these findings, corrective action was recommended to decrease the carbon tetrachloride concentrations in the upper aquifer to acceptable levels (Argonne 1993a,b, 1995). Initial discussions with the Utica village board indicated that any restoration strategies involving nonbeneficial discharge of treated groundwater in the immediate vicinity of Utica would be unacceptable to the town. To address this concern, the CCC/USDA and Argonne, in cooperation with multiple federal and state regulatory and environmental agencies (Table 1.1) proposed a treatment strategy for the Utica groundwater employing groundwater extraction coupled with the seasonal use of agricultural spray irrigation equipment to simultaneously (1) remove carbon tetrachloride from the groundwater (by volatilization to the atmosphere) and (2) discharge the treated groundwater to enhance the development of wetlands in the North Lake Basin Wildlife Management Area, just north of the town (Argonne 2000). To develop this treatment approach, additional groundwater sampling was conducted to update the distribution of carbon tetrachloride in groundwater identified in the preliminary studies in 1992-1993. In March 1998, detailed mapping of the carbon tetrachloride plume was performed by using the Argonne cone penetrometer (CPT) vehicle to collect groundwater samples for analyses for volatile organic compounds (VOCs) at 13 locations (PS01-PS09, PS12, PS16, PS17, PS19; Figure 1.2). The samples were collected in vertical profiles through the aquifer, at 10-ft intervals. The results of this 1998 study (Table 1.2) demonstrated that the three-dimensional distribution of carbon tetrachloride in the aquifer is complex, with multiple 'hot spots' occurring in the plume at various depths and distances along its length (Argonne 2000). In October 2002, the CCC/USDA requested that Argonne perform targeted groundwater sampling at Utica to document the migration of the carbon tetrachloride plume since the 1998 sampling event. In February 2003, vertical-profile groundwater sampling for VOCs analyses was conducted at 8 selected locations (PS01, PS04-PS07, PS12, PS19, PS20; Figure 1.2 and Table 1.3). The lateral and vertical configuration of the carbon tetrachloride plume, as identified in the 2003 study (Argonne 2003), is illustrated in Figures 1.3-1.7. On the basis of the 2003 groundwater sampling results, a remedial system employing four extraction wells (GWEX 1-GWEX 4), with groundwater treatment by spray irrigation and conventional air stripping, was implemented at Utica, with the concurrence of the CCC/USDA and the agencies identified in Table 1.1. The principal components of the Utica system (shown in Figure 1.8) are described briefly in Section 1.2. Operation of well GWEX4 and the associated air stripper began on October 29, 2004, and routine operation of wells GWEX1-GWEX3 and the spray irrigation treatment units began on November 22, 2004.

  18. A new type of environment-friendly material and its removal efficiency for nitrate contaminated groundwater

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Guo, H.

    2014-12-01

    Recently, nitrate contaminated groundwater problem is a growing concern for scholars both at home and abroad. This study developed a new type of environment-friendly material which has the ability to remove nitrate from contaminated groundwater. The material has a certain degree of mechanical strength and uniform sphericity, with waste wood and straw as raw material, to achieve the purpose of using waste treat waste. In this study, the material and fine sand are mixed and filled in glass column, which is wrapped by black tape in order to avoid light, to test the removal ability toward nitrate nitrogen with influent nitrate nitrogen concentration of 50 mg N/L. The material surface is porous, which could facilitate the reaction between the active sites in the material and nitrate in polluted groundwater, and facilitate microbes implanting on the surface. After running for two months, the nitrate nitrogen removal rate is greater than 90%, and the nitrate nitrogen and nitrite nitrogen of effluent are lower than the EPA prescribed maximum limit concentration of nitrate in drinking water?N03--N<10mg N/L, NO2--N<1mg N/L?, while the ammonia nitrogen in the effluent is less than 1 mg N/L, lower than the maximum limit concentration of ammonia nitrogen in drinking water made by WHO(NH4+-N<1.5mg N/L), indicating its effective removal rate for nitrate and the absence of serious nitrite and ammonia accumulation. The developed material will have a good prospect in removing nitrate from polluted groundwater.

  19. Characterization and microbial utilization of dissolved organic carbon in groundwater contaminated with chlorophenols.

    PubMed

    Langwaldt, J H; Münster, U; Puhakka, J A

    2005-05-01

    The aim of this study was to characterize the labile part of dissolved organic carbon (DOC) present in groundwater by identification of natural organic carbon substrates and to assess their microbial utilization during aeration of the groundwater. The studied chlorophenol (CP) contaminated groundwater contained 60-2650 micromoll(-1) of DOC of which up to 98.0% were CPs; 1.7% were low-molecular weight organic acids and 0.2% were dissolved free amino acids. Traces of following natural organic carbon substrates were identified: L-alanine, L-isoleucine, L-leucine, L-serine, L-threonine, L-tyrosine, L-valine, L-aspartic, acetic, citric, formic, lactic, malic and oxalic acid. Dissolved oxygen concentration inside the CP-plume was lower (mean 25 micromoll(-1)) than outside of the plume (mean 102 micromoll(-1)). Over a monitoring period of four years the concentrations of CPs, Fe(II) and NH4+ were higher inside than outside of the CP-plume. Oxygen availability within the CP-plume limits in situ biological oxidation of CPs, DOC, NH4+ and Fe(II). The microbial enzymatic hydrolysis rates of 4-methylumbelliferyl and 7-amino-4-methylcoumarin-linked substrates varied from 0.01 to 52 micromoll(-1)h(-1) and was slightly higher inside than outside the plume. Microbial uptake rates of 14C-acetate, 14C-glucose and 14C-leucine were on average 28, 4 and 4 pmoll(-1)h(-1) outside and 17, 25 and 8 pmoll(-1)h(-1) inside the plume, respectively. The indigenous microorganisms were shown able of hydrolysis of dissolved organic matter, uptake and utilization of natural organic carbon substrates. Therefore, the labile part of DOC serves as a pool of secondary substrates beside the CP-contaminants in the groundwater and possibly help in sustaining the growth of CP-degrading bacteria. PMID:15823332

  20. Evaluation of the atmosphere as a source of volatile organic compounds in shallow groundwater

    USGS Publications Warehouse

    Baehr, A.L.; Stackelberg, P.E.

    1999-01-01

    The atmosphere as a source of volatile organic compounds (VOCs) in shallow groundwater was evaluated over an area in southern New Jersey. Chloroform, methyl tertbutyl ether (MTBE), 1,1,1-trichloroethane, tetrachloroethylene (PCE), and carbon disulfide (not a VOC) were detected frequently at low-level concentrations in a network of 78 shallow wells in the surficial Kirkwood-Cohansey aquifer system. The atmosphere was sampled for these compounds and only MTBE concentrations were high enough to potentially explain frequent detection in shallow groundwater. A mathematical model of reactive transport through the unsaturated zone is presented to explain how variations in unsaturated properties across the study area could explain differences in MTBE concentrations in shallow groundwater given the atmosphere as the source. Even when concentrations of VOCs in groundwater are low compared to regulatory concentration limits, it is critical to know the source. If the VOCs originate from a point source(s), concentrations in groundwater could potentially increase over time to levels of concern as groundwater plumes evolve, whereas if the atmosphere is the source, then groundwater concentrations would be expected to remain at low-level concentrations not exceeding those in equilibrium with atmospheric concentrations. This is the first analysis of VOC occurrence in shallow groundwater involving colocated atmosphere data.The atmosphere as a source of volatile organic compounds (VOCs) in shallow groundwater was evaluated over an area in southern New Jersey. Chloroform, methyl tert-butyl ether (MTBE), 1,1,1-trichloroethane, tetrachloroethylene (PCE), and carbon disulfide (not a VOC) were detected frequently at low-level concentrations in a network of 78 shallow wells in the surficial Kirkwood-Cohansey aquifer system. The atmosphere was sampled for these compounds and only MTBE concentrations were high enough to potentially explain frequent detection in shallow groundwater. A mathematical model of reactive transport through the unsaturated zone is presented to explain how variations in unsaturated properties across the study area could explain differences in MTBE concentrations in shallow groundwater given the atmosphere as the source. Even when concentrations of VOCs in groundwater are low compared to regulatory concentration limits, it is critical to know the source. If the VOCs originate from a point source(s), concentrations in groundwater could potentially increase over time to levels of concern as groundwater plumes evolve, whereas if the atmosphere is the source, then groundwater concentrations would be expected to remain at low-level concentrations not exceeding those in equilibrium with atmospheric concentrations. This is the first analysis of VOC occurrence in shallow groundwater involving collocated atmosphere data.

  1. Alternative Endpoints and Approaches for the Remediation of Contaminated Groundwater at Complex Sites - 13426

    SciTech Connect

    Deeb, Rula A.; Hawley, Elisabeth L. [ARCADIS, U.S., 2000 Powell St., 7th Floor, Emeryville, California 94608 (United States)] [ARCADIS, U.S., 2000 Powell St., 7th Floor, Emeryville, California 94608 (United States)

    2013-07-01

    The goal of United States (U.S.) Department of Energy's (DOE)'s environmental remediation programs is to restore groundwater to beneficial use, similar to many other Federal and state environmental cleanup programs. Based on past experience, groundwater remediation to pre-contamination conditions (i.e., drinking water standards or non-detectable concentrations) can be successfully achieved at many sites. At a subset of the most complex sites, however, complete restoration is not likely achievable within the next 50 to 100 years using today's technology. This presentation describes several approaches used at complex sites in the face of these technical challenges. Many complex sites adopted a long-term management approach, whereby contamination was contained within a specified area using active or passive remediation techniques. Consistent with the requirements of their respective environmental cleanup programs, several complex sites selected land use restrictions and used risk management approaches to accordingly adopt alternative cleanup goals (alternative endpoints). Several sites used long-term management designations and approaches in conjunction with the alternative endpoints. Examples include various state designations for groundwater management zones, technical impracticability (TI) waivers or greater risk waivers at Superfund sites, and the use of Monitored Natural Attenuation (MNA) or other passive long-term management approaches over long time frames. This presentation will focus on findings, statistics, and case studies from a recently-completed report for the Department of Defense's Environmental Security Technology Certification Program (ESTCP) (Project ER-0832) on alternative endpoints and approaches for groundwater remediation at complex sites under a variety of Federal and state cleanup programs. The primary objective of the project was to provide environmental managers and regulators with tools, metrics, and information needed to evaluate alternative endpoints for groundwater remediation at complex sites. A statistical analysis of Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) sites receiving TI waivers will be presented as well as case studies of other types of alternative endpoints and alternative remedial strategies that illustrate the variety of approaches used at complex sites and the technical analyses used to predict and document cost, time frame, and potential remedial effectiveness. This presentation is intended to inform DOE program managers, state regulators, practitioners and other stakeholders who are evaluating technical cleanup challenges within their own programs, and establishing programmatic approaches to evaluating and implementing long-term management approaches. Case studies provide examples of long-term management designations and strategies to manage and remediate groundwater at complex sites. At least 13 states consider some designation for groundwater containment in their corrective action policies, such as groundwater management zones, containment zones, and groundwater classification exemption areas. Long-term management designations are not a way to 'do nothing' or walk away from a site. Instead, soil and groundwater within the zone is managed to be protective of human health and the environment. Understanding when and how to adopt a long-term management approach can lead to cost savings and the more efficient use of resources across DOE and at numerous other industrial and military sites across the U.S. This presentation provides context for assessing the use and appropriate role of alternative endpoints and supporting long-term management designations in final remedies. (authors)

  2. Ground-water contamination at an inactive coal and oil gasification plant site, Gas Works Park, Seattle, Washington

    USGS Publications Warehouse

    Turney, G.L.; Goerlitz, D.F.

    1989-01-01

    Gas Works Park, in Seattle, Washington, is located on the site of a coal and oil gasification plant that ceased operation in 1956. During operation, many types of wastes, including coal, tar, and oil, accumulated on site. The park soil is presently (1986) contaminated with compounds such as polynuclear aromatic hydrocarbons, volatile organic compounds, trace metals, and cyanide. Analyses of water samples from a network of observation wells in the park indicate that these compounds are also present in the groundwater. Polynuclear aromatic hydrocarbons and volatile organic compounds were identified in groundwater samples in concentrations as large as 200 mg/L. Concentrations of organic compounds were largest where groundwater was in contact with a nonaqueous phase liquid in the soil. Concentrations in groundwater were much smaller where no nonaqueous phase liquid was present, even if the groundwater was in contact with contaminated soils. This condition is attributed to weathering processes at the site, such as dissolution, volatilization, and biodegradation. Soluble, volatile, low-molecular-weight organic compounds are preferentially dissolved from the nonaqueous phase liquid into the groundwater. Where no nonaqueous phase liquid is present, only stained soils containing relatively insoluble, high-molecular-weight compounds remain; therefore, contaminant concentrations in the groundwater are much smaller. Concentrations of organic contaminants in the soils may still remain large. Values of specific conductance were as large as 5,280 microsiemens/cm, well above a background of 242 microsiemens/cm, suggesting large concentrations of minerals in the groundwater. Trace metal concentrations, however , were generally < 0.010 mg/L, and below limits of US EPA drinking water standards. Cyanide was present in groundwater samples from throughout the park, ranging in concentration from 0.01 to 8.6 mg/L. (Author 's abstract)

  3. Application of artificial neural networks to assess pesticide contamination in shallow groundwater

    USGS Publications Warehouse

    Sahoo, G.B.; Ray, C.; Mehnert, E.; Keefer, D.A.

    2006-01-01

    In this study, a feed-forward back-propagation neural network (BPNN) was developed and applied to predict pesticide concentrations in groundwater monitoring wells. Pesticide concentration data are challenging to analyze because they tend to be highly censored. Input data to the neural network included the categorical indices of depth to aquifer material, pesticide leaching class, aquifer sensitivity to pesticide contamination, time (month) of sample collection, well depth, depth to water from land surface, and additional travel distance in the saturated zone (i.e., distance from land surface to midpoint of well screen). The output of the neural network was the total pesticide concentration detected in the well. The model prediction results produced good agreements with observed data in terms of correlation coefficient (R = 0.87) and pesticide detection efficiency (E = 89%), as well as good match between the observed and predicted "class" groups. The relative importance of input parameters to pesticide occurrence in groundwater was examined in terms of R, E, mean error (ME), root mean square error (RMSE), and pesticide occurrence "class" groups by eliminating some key input parameters to the model. Well depth and time of sample collection were the most sensitive input parameters for predicting the pesticide contamination potential of a well. This infers that wells tapping shallow aquifers are more vulnerable to pesticide contamination than those wells tapping deeper aquifers. Pesticide occurrences during post-application months (June through October) were found to be 2.5 to 3 times higher than pesticide occurrences during other months (November through April). The BPNN was used to rank the input parameters with highest potential to contaminate groundwater, including two original and five ancillary parameters. The two original parameters are depth to aquifer material and pesticide leaching class. When these two parameters were the only input parameters for the BPNN, they were not able to predict contamination potential. However, when they were used with other parameters, the predictive performance efficiency of the BPNN in terms of R, E, ME, RMSE, and pesticide occurrence "class" groups increased. Ancillary data include data collected during the study such as well depth and time of sample collection. The BPNN indicated that the ancillary data had more predictive power than the original data. The BPNN results will help researchers identify parameters to improve maps of aquifer sensitivity to pesticide contamination. ?? 2006 Elsevier B.V. All rights reserved.

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

    USGS Publications Warehouse

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

    1986-01-01

    Study of ground-water contamination at Wurtsmith Air Force Base, Michigan, defined the movement and distribution of volatile organic compounds in the glacial sand and gravel aquifer at known sites of contamination, and has defined new plumes at two other sites. The Arrow Street purge system, installed in 1982 to remove contaminants from the Building 43 plume, has lowered concentrations of trichloroethylene (TCE) in groundwater in the central part of the most contaminated area from a range of 1,000 to 2,000 microg/L to about 200 microg/L. TCE is not escaping off-Base from this area. In the southern part of the Base a plume containing principally TCE and dichloroethylene (DCE) has been delineated along Mission Drive. Maximum concentrations observed were 3,290 microg/L of TCE and 1,480 microg/L of DCE. Hydrologically suitable sites for purge wells were identified in the southern part of the plume using a new ground-water flow model of the Base. A benzene plume near the bulk-fuel storage area has shifted to a more northerly direction under influence of the Arrow Street purge system. Sites initially identified for purging the benzene plume have been repositioned because of the change in contaminant movement. JP-4 fuel was found to be accumulating in wells near the bulk-fuel storage area, largely in response to seasonal fluctuations in the water-table. It is thought to originate from a spill that occurred several years ago. In general, concentrations found in water do not differ greatly from those observed in 1981. Since 1981, concentrations of TCE have decreased significantly in the Alert Apron plume. Near the origin of the plume, the concentration of TCE has decreased from 1,000 microg/L in 1980 to 50 microg/L in 1984. Water from Van Etten Lake near the termination of the plume had only a trace of TCE at one site. Benzene detected in water from well AF2 seems to originate near the former site of buried fuel tanks west of the operational apron. During periods of normal purge pumping along Arrow Street, contaminants are drawn toward water-supply wells AF2, AF4, and AF5. (Author 's abstract)

  5. Arsenic groundwater contamination in Middle Ganga Plain, Bihar, India: a future danger?

    PubMed Central

    Chakraborti, Dipankar; Mukherjee, Subhash C; Pati, Shyamapada; Sengupta, Mrinal K; Rahman, Mohammad M; Chowdhury, Uttam K; Lodh, Dilip; Chanda, Chitta R; Chakraborti, Anil K; Basu, Gautam K

    2003-01-01

    The pandemic of arsenic poisoning due to contaminated groundwater in West Bengal, India, and all of Bangladesh has been thought to be limited to the Ganges Delta (the Lower Ganga Plain), despite early survey reports of arsenic contamination in groundwater in the Union Territory of Chandigarh and its surroundings in the northwestern Upper Ganga Plain and recent findings in the Terai area of Nepal. Anecdotal reports of arsenical skin lesions in villagers led us to evaluate arsenic exposure and sequelae in the Semria Ojha Patti village in the Middle Ganga Plain, Bihar, where tube wells replaced dug wells about 20 years ago. Analyses of the arsenic content of 206 tube wells (95% of the total) showed that 56.8% exceeded arsenic concentrations of 50 micro g/L, with 19.9% > 300 micro g/L, the concentration predicting overt arsenical skin lesions. On medical examination of a self-selected sample of 550 (390 adults and 160 children), 13% of the adults and 6.3% of the children had typical skin lesions, an unusually high involvement for children, except in extreme exposures combined with malnutrition. The urine, hair, and nail concentrations of arsenic correlated significantly (r = 0.72-0.77) with drinking water arsenic concentrations up to 1,654 micro g/L. On neurologic examination, arsenic-typical neuropathy was diagnosed in 63% of the adults, a prevalence previously seen only in severe, subacute exposures. We also observed an apparent increase in fetal loss and premature delivery in the women with the highest concentrations of arsenic in their drinking water. The possibility of contaminated groundwater at other sites in the Middle and Upper Ganga Plain merits investigation. PMID:12842773

  6. Functional gene array-based analysis of microbial community structure in groundwater with gradient of contaminant levels

    SciTech Connect

    Wu, Liyou [University of Oklahoma, Norman; Van Nostrand, Joy [University of Oklahoma, Norman; Schadt, Christopher Warren [ORNL; Watson, David B [ORNL; Jardine, Philip M [ORNL; Palumbo, Anthony Vito [ORNL; Hazen, Terry [Lawrence Berkeley National Laboratory (LBNL); Zhou, Jizhong [University of Oklahoma, Norman

    2009-04-01

    To understand how contaminants affect microbial community diversity, heterogeneity, and functional structure, six groundwater monitoring wells from the Field Research Center of the U.S. Department of Energy Environmental Remediation Science Program (ERSP; Oak Ridge, TN), with a wide range of pH, nitrate, and heavy metal contamination were investigated. DNA from the groundwater community was analyzed with a functional gene array containing 2006 probes to detect genes involved in metal resistance, sulfate reduction, organic contaminant degradation, and carbon and nitrogen cycling. Microbial diversity decreased in relation to the contamination levels of the wells. Highly contaminated wells had lower gene diversity but greater signal intensity than the pristine well. The microbial composition was heterogeneous, with 17?70% overlap between different wells. Metal-resistant and metal-reducing microorganisms were detected in both contaminated and pristine wells, suggesting the potential for successful bioremediation of metal-contaminated groundwaters. In addition, results of Mantel tests and canonical correspondence analysis indicate that nitrate, sulfate, pH, uranium, and technetium have a significant (p < 0.05) effect on microbial community structure. This study provides an overall picture of microbial community structure in contaminated environments with functional gene arrays by showing that diversity and heterogeneity can vary greatly in relation to contamination.

  7. Functional gene array-based analysis of microbial community structure in groundwaters with a gradient of contaminant levels

    SciTech Connect

    Waldron, P.J.; Wu, L.; Van Nostrand, J.D.; Schadt, C.W.; Watson, D.B.; Jardine, P.M.; Palumbo, A.V.; Hazen, T.C.; Zhou, J.

    2009-06-15

    To understand how contaminants affect microbial community diversity, heterogeneity, and functional structure, six groundwater monitoring wells from the Field Research Center of the U.S. Department of Energy Environmental Remediation Science Program (ERSP; Oak Ridge, TN), with a wide range of pH, nitrate, and heavy metal contamination were investigated. DNA from the groundwater community was analyzed with a functional gene array containing 2006 probes to detect genes involved in metal resistance, sulfate reduction, organic contaminant degradation, and carbon and nitrogen cycling. Microbial diversity decreased in relation to the contamination levels of the wells. Highly contaminated wells had lower gene diversity but greater signal intensity than the pristine well. The microbial composition was heterogeneous, with 17-70% overlap between different wells. Metal-resistant and metal-reducing microorganisms were detected in both contaminated and pristine wells, suggesting the potential for successful bioremediation of metal-contaminated groundwaters. In addition, results of Mantel tests and canonical correspondence analysis indicate that nitrate, sulfate, pH, uranium, and technetium have a significant (p < 0.05) effect on microbial community structure. This study provides an overall picture of microbial community structure in contaminated environments with functional gene arrays by showing that diversity and heterogeneity can vary greatly in relation to contamination.

  8. Dual wall reverse circulation drilling with multi-level groundwater sampling for groundwater contaminant plume delineation at Paducah Gaseous Diffusion Plant, Paducah, Kentucky

    SciTech Connect

    Smuin, D.R.; Morti, E.E.; Zutman, J.L.; Pickering, D.A.

    1995-08-01

    Dual wall reverse circulation (DWRC) drilling was used to drill 48 borings during a groundwater contaminant investigation at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky. This method was selected as an alternative to conventional hollow stem auger drilling for a number of reasons, including the expectation of minimizing waste, increasing the drilling rate, and reducing the potential for cross contamination of aquifers. Groundwater samples were collected from several water-bearing zones during drilling of each borehole. The samples were analyzed for volatile organic compounds using a field gas chromatograph. This approach allowed the investigation to be directed using near-real-time data. Use of downhole geophysical logging, in conjunction with lithologic descriptions of borehole cuttings, resulted in excellent correlation of the geology in the vicinity of the contaminant plume. The total volume of cuttings generated using the DWRC drilling method was less than half of what would have been produced by hollow stem augering; however, the cuttings were recovered in slurry form and had to be dewatered prior to disposal. The drilling rate was very rapid, often approaching 10 ft/min; however, frequent breaks to perform groundwater sampling resulted in an average drilling rate of < 1 ft/min. The time required for groundwater sampling could be shortened by changing the sampling methodology. Analytical results indicated that the drilling method successfully isolated the various water bearing zones and no cross contamination resulted from the investigation.

  9. Addressing Uncertainty in Contaminant Transport in Groundwater Using the Ensemble Kalman Filter

    NASA Astrophysics Data System (ADS)

    Dwivedi, D.; Mohanty, B. P.

    2011-12-01

    Nitrate in groundwater shows significant uncertainty which arises from sparse data and interaction among multiple geophysical factors such as source availability (land use), thickness and composition of the vadose zone, types of aquifers (confined or unconfined), aquifer heterogeneity (geological and alluvial), precipitation characteristics, etc. This work presents the fusion of the ensemble Kalman filter (EnKF) with the numerical groundwater flow model MODFLOW and the solute transport model MT3DMS. The EnKF is a sequential data assimilation approach, which is applied to quantify and reduce the uncertainty of groundwater flow and solute transport models. We conducted numerical simulation experiments for the period January 1990 to December 2005 with MODFLOW and MT3DMS models for variably saturated groundwater flow in various aquifers across Texas. The EnKF was used to update the model parameters, hydraulic conductivity, hydraulic head and solute concentration. Results indicate that the EnKF method notably improves the estimation of the hydraulic conductivity distribution and solute transport prediction by assimilating piezometric head measurements with a known nitrate initial condition. A better estimation of hydraulic conductivity and assimilation of continuous measurements of solute concentrations resulted in reduced uncertainty in MODFLOW and MT3DMS models. It was found that the observation locations and locations in spatial proximity were appropriately corrected by the EnKF. The knowledge of nitrate plume evolution provided an insight into model structure, parameters, and sources of uncertainty.

  10. Effects of land use on ground-water quality in central Florida; preliminary results, US Geological Survey Toxic Waste-Ground Water Contamination Program

    USGS Publications Warehouse

    Rutledge, A.T.

    1987-01-01

    Groundwater is the principal source of drinking water in central Florida. The most important hydrogeologic unit is the Floridan aquifer system, consisting of fractured limestone and dolomite limestone. Activities of man in areas of recharge to the Floridian aquifer system that may be affecting groundwater quality include: (1) the use of drainage wells for stormwater disposal in urban areas, (2) the use of pesticides and fertilizers in citrus groves, and (3) the mining and processing of phosphate ore in mining areas. Preliminary findings about the impacts of these land uses on ground-water quality by comparison with a fourth land use representing the absence of human activity in another area of recharge are presented. Drainage wells convey excess urban stormwater directly to the Upper Floridian aquifer. The volatile organic compounds are the most common contaminants in ground water. Trace elements such as chromium and lead are entering the aquifer but their movement is apparently attenuated by precipitation reactions associated with high pH or by cation-exchange reactions. Among the trace elements and organic chemicals, most ground-water contamination in citrus production areas is caused by pesticides, which include the organic compounds simazine, ametryne, chlordane, DDE , bromacil, aldicarb, EDB, trifluralin, and diazinon, and the trace elements zinc and copper; other contaminants include benzene, toluene, napthalene, and indene compounds. In the phosphate mining area, constituents of concern are arsenic, selenium, and mercury, and secondarily lead, chromium, cadmium, and others. Organic compounds such as fluorene, naphthalene, di-n-butyl phthalate, alkylated benzenes and naphthalenes, and indene compounds also are entering groundwater. (Author 's abstract)

  11. Groundwater Quality, Age, and Probability of Contamination, Eagle River Watershed Valley-Fill Aquifer, North-Central Colorado, 2006-2007

    USGS Publications Warehouse

    Rupert, Michael G.; Plummer, L. Niel

    2009-01-01

    The Eagle River watershed is located near the destination resort town of Vail, Colorado. The area has a fastgrowing permanent population, and the resort industry is rapidly expanding. A large percentage of the land undergoing development to support that growth overlies the Eagle River watershed valley-fill aquifer (ERWVFA), which likely has a high predisposition to groundwater contamination. As development continues, local organizations need tools to evaluate potential land-development effects on ground- and surface-water resources so that informed land-use and water management decisions can be made. To help develop these tools, the U.S. Geological Survey (USGS), in cooperation with Eagle County, the Eagle River Water and Sanitation District, the Town of Eagle, the Town of Gypsum, and the Upper Eagle Regional Water Authority, conducted a study in 2006-2007 of the groundwater quality, age, and probability of contamination in the ERWVFA, north-central Colorado. Ground- and surface-water quality samples were analyzed for major ions, nutrients, stable isotopes of hydrogen and oxygen in water, tritium, dissolved gases, chlorofluorocarbons (CFCs), and volatile organic compounds (VOCs) determined with very low-level laboratory methods. The major-ion data indicate that groundwaters in the ERWVFA can be classified into two major groups: groundwater that was recharged by infiltration of surface water, and groundwater that had less immediate recharge from surface water and had elevated sulfate concentrations. Sulfate concentrations exceeded the USEPA National Secondary Drinking Water Regulations (250 milligrams per liter) in many wells near Eagle, Gypsum, and Dotsero. The predominant source of sulfate to groundwater in the Eagle River watershed is the Eagle Valley Evaporite, which is a gypsum deposit of Pennsylvanian age located predominantly in the western one-half of Eagle County.

  12. Assessing TNT and DNT groundwater contamination by compound-specific isotope analysis and 3H-3He groundwater dating: a case study in Portugal.

    PubMed

    Amaral, Helena I F; Fernandes, Judite; Berg, Michael; Schwarzenbach, René P; Kipfer, Rolf

    2009-10-01

    Trinitrotoluene (TNT) and dinitrotoluene (DNT) originating from 50 years of explosives production have heavily contaminated two stacked aquifers in the vicinity of Lisboa, Portugal. To assess if these poly-nitroaromatic compounds (P-NACs) are being degraded in the subsurface, tracer-based groundwater dating techniques combined with compound-specific isotope analyses (CSIA) were applied. The groundwater residence times were distinctly different in the two aerobic aquifers, as determined by the tritium ((3)H)-(3)He method. In the contaminated zones, the upper aquifer exhibited groundwater ages of 25 years, whereas the lower (presumably confined) aquifer contained hardly any tritium which indicates water ages >55 years. P-NACs-containing waste waters are known to have leaked into the upper, unconfined aquifer. However, P-NACs were present in both aquifers in high concentrations (up to 33000 microg L(-1) TNT), which implies a hydraulic connection, although tritium concentrations and chemical data suggest two separated aquifers. Based on the (3)H-(3)He groundwater dating and the presence of very high P-NAC concentrations, the contamination of the lower aquifer must have happened during the early stage of the explosive production, i.e. >50 years ago. Despite this 'old' contamination, TNT and DNT have not been transformed until to date as is demonstrated by the negligible changes in their carbon isotopic signatures (delta(13)C). Thus, P-NACs are very recalcitrant to degradation at the investigated site. If the aquifers remain aerobic, TNT and DNT are expected to persist in the subsurface for many decades to centuries. The presented approach of assessing time scales of natural attenuation at the field scale by the combination of CSIA and (3)H-(3)He water dating has the potential to be applied to any other groundwater contaminants, such as chlorinated hydrocarbons, gasoline components, heterocyclic carbenes, or polyaromatic hydrocarbons. PMID:19740509

  13. Molybdenum Availability Is Key to Nitrate Removal in Contaminated Groundwater Environments.

    PubMed

    Thorgersen, Michael P; Lancaster, W Andrew; Vaccaro, Brian J; Poole, Farris L; Rocha, Andrea M; Mehlhorn, Tonia; Pettenato, Angelica; Ray, Jayashree; Waters, R Jordan; Melnyk, Ryan A; Chakraborty, Romy; Hazen, Terry C; Deutschbauer, Adam M; Arkin, Adam P; Adams, Michael W W

    2015-08-01

    The concentrations of molybdenum (Mo) and 25 other metals were measured in groundwater samples from 80 wells on the Oak Ridge Reservation (ORR) (Oak Ridge, TN), many of which are contaminated with nitrate, as well as uranium and various other metals. The concentrations of nitrate and uranium were in the ranges of 0.1 ?M to 230 mM and <0.2 nM to 580 ?M, respectively. Almost all metals examined had significantly greater median concentrations in a subset of wells that were highly contaminated with uranium (?126 nM). They included cadmium, manganese, and cobalt, which were 1,300- to 2,700-fold higher. A notable exception, however, was Mo, which had a lower median concentration in the uranium-contaminated wells. This is significant, because Mo is essential in the dissimilatory nitrate reduction branch of the global nitrogen cycle. It is required at the catalytic site of nitrate reductase, the enzyme that reduces nitrate to nitrite. Moreover, more than 85% of the groundwater samples contained less than 10 nM Mo, whereas concentrations of 10 to 100 nM Mo were required for efficient growth by nitrate reduction for two Pseudomonas strains isolated from ORR wells and by a model denitrifier, Pseudomonas stutzeri RCH2. Higher concentrations of Mo tended to inhibit the growth of these strains due to the accumulation of toxic concentrations of nitrite, and this effect was exacerbated at high nitrate concentrations. The relevance of these results to a Mo-based nitrate removal strategy and the potential community-driving role that Mo plays in contaminated environments are discussed. PMID:25979890

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

    PubMed

    Brunsting, Joseph H; McBean, Edward A

    2014-04-01

    Arsenic contamination of groundwater is a major problem in some areas of the world, particularly in West Bengal (India) and Bangladesh where it is caused by reducing conditions in the aquifer. In situ treatment, if it can be proven as operationally feasible, has the potential to capture some advantages over other treatment methods by being fairly simple, not using chemicals, and not necessitating disposal of arsenic-rich wastes. In this study, the potential for in situ treatment by injection of compressed air directly into the aquifer (i.e. air sparging) is assessed. An experimental apparatus was constructed to simulate conditions of arsenic-rich groundwater under anaerobic conditions, and in situ treatment by air sparging was employed. Arsenic (up to 200 ?g/L) was removed to a maximum of 79% (at a local point in the apparatus) using a solution with dissolved iron and arsenic only. A static "jar" test revealed arsenic removal by co-precipitation with iron at a molar ratio of approximately 2 (iron/arsenic). This is encouraging since groundwater with relatively high amounts of dissolved iron (as compared to arsenic) therefore has a large theoretical treatment capacity for arsenic. Iron oxidation was significantly retarded at pH values below neutral. In terms of operation, analysis of experimental results shows that periodic air sparging may be feasible. PMID:24561624

  15. Prediction of uranium and technetium sorption during titration of contaminated acidic groundwater

    SciTech Connect

    Zhang, Fan [ORNL; Parker, Jack C. [University of Tennessee, Knoxville (UTK); Watson, David B [ORNL; Jardine, Philip M [ORNL; Gu, Baohua [ORNL

    2010-01-01

    This study investigates uranium and technetium sorption onto aluminum and iron hydroxides during titration of acidic groundwater. The contaminated groundwater exhibits oxic conditions with high concentrations of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, U, Tc, and various metal cations. More than 90% of U and Tc was removed from the aqueous phase as Al and Fe precipitated above pH 5.5, but was partially resolublized at higher pH values. An equilibrium hydrolysis and precipitation reaction model adequately described variations in aqueous concentrations of metal cations. An anion exchange reaction model was incorporated to simulate sulfate, U and Tc sorption onto variably charged (pH-dependent) Al and Fe hydroxides. Modeling results indicate that competitive sorption/desorption on mixed mineral phases needs to be considered to adequately predict U and Tc mobility. The model could be useful for future studies of the speciation of U, Tc and co-existing ions during pre- and post-groundwater treatment practices.

  16. A compositional multiphase model for groundwater contamination by petroleum products. 2. Numerical solution

    USGS Publications Warehouse

    Baehr, A.L.; Corapcioglu, M.Y.

    1987-01-01

    In this paper we develop a numerical solution to equations developed in part 1 (M.Y. Corapcioglu and A.L. Baehr, this issue) to predict the fate of an immiscible organic contaminant such as gasoline in the unsaturated zone subsequent to plume establishment. This solution, obtained by using a finite difference scheme and a method of forward projection to evaluate nonlinear coefficients, provides estimates of the flux of solubilized hydrocarbon constituents to groundwater from the portion of a spill which remains trapped in a soil after routine remedial efforts to recover the product have ceased. The procedure was used to solve the one-dimensional (vertical) form of the system of nonlinear partial differential equations defining the transport for each constituent of the product. Additionally, a homogeneous, isothermal soil with constant water content was assumed. An equilibrium assumption partitions the constituents between air, water, adsorbed, and immiscible phases. Free oxygen transport in the soil was also simulated to provide an upper bound estimate of aerobic biodegradation rates. Results are presented for a hypothetical gasoline consisting of eight groups of hydrocarbon constituents. Rates at which hydrocarbon mass is removed from the soil, entering either the atmosphere or groundwater, or is biodegraded are presented. A significant sensitivity to model parameters, particularly the parameters characterizing diffusive vapor transport, was discovered. We conclude that hypocarbon solute composition in groundwater beneath a gasoline contaminated soil would be heavily weighted toward aromatic constituents like benzene, toluene, and xylene.In this paper we develop a numerical solution to equations developed in part 1 (M. Y. Corapcioglu and A. L. Baehr, this issue) to predict the fate of an immiscible organic contaminant such as gasoline in the unsaturated zone subsequent to plume establishment. This solution, obtained by using a finite difference scheme and a method of forward projection to evaluate nonlinear coefficients, provides estimates of the flux of solubilized hydrocarbon constituents to groundwater from the portion of a spill which remains trapped in a soil after routine remedial efforts to recover the product have ceased. The procedure was used to solve the one-dimensional (vertical) form of the system of nonlinear partial differential equations defining the transport for each constituent of the product. Additionally, a homogeneous, isothermal soil with constant water content was assumed.

  17. In situ stimulation of groundwater denitrification with formate to remediate nitrate contamination

    USGS Publications Warehouse

    Smith, R.L.; Miller, D.N.; Brooks, M.H.; Widdowson, M.A.; Killingstad, M.W.

    2001-01-01

    In situ stimulation of denitrification has been proposed as a mechanism to remediate groundwater nitrate contamination. In this study, sodium formate was added to a sand and gravel aquifer on Cape Cod, MA, to test whether formate could serve as a potential electron donor for subsurface denitrification. During 16- and 10-day trials, groundwater from an anoxic nitrate-containing zone (0.5-1.5 mM) was continuously withdrawn, amended with formate and bromide, and pumped back into the aquifer. Concentrations of groundwater constituents were monitored in multilevel samplers after up to 15 m of transport by natural gradient flow. Nitrate and formate concentrations were decreased 80-100% and 60-70%, respectively, with time and subsequent travel distance, while nitrite concentrations inversely increased. The field experiment breakthrough curves were simulated with a two-dimensional site-specific model that included transport, denitrification, and microbial growth. Initial values for model parameters were obtained from laboratory incubations with aquifer core material and then refined to fit field breakthrough curves. The model and the lab results indicated that formate-enhanced nitrite reduction was nearly 4-fold slower than nitrate reduction, but in the lab, nitrite was completely consumed with sufficient exposure time. Results of this study suggest that a long-term injection of formate is necessary to test the remediation potential of this approach for nitrate contamination and that adaptation to nitrite accumulation will be a key determinative factor.In situ stimulation of denitrification has been proposed as a mechanism to remediate groundwater nitrate contamination. In this study, sodium formate was added to a sand and gravel aquifer on Cape Cod, MA, to test whether formate could serve as a potential electron donor for subsurface denitrification. During 16- and 10-day trials, groundwater from an anoxic nitrate-containing zone (0.5-1.5 mM) was continuously withdrawn, amended with formate and bromide, and pumped back into the aquifer. Concentrations of groundwater constituents were monitored in multilevel samplers after up to 15 m of transport by natural gradient flow. Nitrate and formate concentrations were decreased 80-100% and 60-70%, respectively, with time and subsequent travel distance, while nitrite concentrations inversely increased. The field experiment breakthrough curves were simulated with a two-dimensional site-specific model that included transport, denitrification, and microbial growth. Initial values for model parameters were obtained from laboratory incubations with aquifer core material and then refined to fit field breakthrough curves. The model and the lab results indicated that formate-enhanced nitrite reduction was nearly 4-fold slower than nitrate reduction, but in the lab, nitrite was completely consumed with sufficient exposure time. Results of this study suggest that a long-term injection of formate is necessary to test the remediation potential of this approach for nitrate contamination and that adaptation to nitrite accumulation will be a key determinative factor.

  18. Biological treatment of groundwater contaminated with mixtures of aromatic compounds. Final report, August-December 1990

    SciTech Connect

    Pettigrew, C.A.; Spain, J.; Vogel, C.M.

    1993-03-01

    This report presents the results of a 3-week preliminary field demonstration using an aboveground fixed-film bioreactor to biodegrade chlorinated aromatic compounds. The site at Kelly AFB, TX is an abandoned waste storage area where the soil and groundwater is contaminated with a mixture of chlorinated solvents. Contaminant removal by a reactor colonized with Pseudomonas sp. JS150 was compared to that of a reactor colonized with indigenous groundwater bacteria. Other process measurements included temperature, pH, dissolved oxygen, and fluctuations in microbial populations. Both biofilm populations degraded the organic compounds when the reactors were operated at a hydraulic residence time of 40 minutes. The concentrations of volatile organic compounds were reduced from the mg/l to the low ug/l range when sufficient dissolved oxygen was maintained. These results indicate that high removal efficiencies for complex mixtures of organic compounds can be achieved by immobilized bacterial populations. Bioremediation, Fixed-film bioreactor, Pseudomonas strain JS150, Chlorinated aromatic compounds.

  19. Treatment of saline, acidic, metal-contaminated groundwater from the Western Australian Wheatbelt.

    PubMed

    Franzmann, P D; Plumb, J J; Wylie, J T; Robertson, W J; Douglas, G B; Bastow, T P; Kaksonen, A H; Puhakka, J A

    2008-01-01

    Managing acidic, metal-containing saline ground and drainage waters in the Wheatbelt of Western Australia is an environmental and economic challenge. Sulfate-reducing fluidised bed bioreactors are shown to be technically capable of treating high salt, low pH, metal containing waters from the town of Narembeen in the Wheatbelt so as to reduce acidity and to remove most of the undesirable metal contaminants. The hydraulic residence time (HRT) limit for a stable process with groundwater from the region of Narembeen was >16 hours. The maximal rate of sulfate reduction in the laboratory system treating Narembeen groundwater was similar to rates observed in comparable applications of the process at other sites, ca. 3 g sulfate (L-reactor)(-1) day(-1). Salts that are relatively free of metal contaminants can be produced from water that has been treated by the sulfate-reducing fluidised bed bioreactor. It is unlikely that metal precipitates, captured from Wheatbelt waters by the process, would be of economic value. If sulfate-reducing fluidised bed reactors were considered technologically appropriate at larger scale, the decision to use them would be based on the necessity to take action, the comparative effectiveness of competing technologies, and the relative costs of competing technologies. PMID:19092214

  20. Waste and cost reduction using dual wall reverse circulation drilling with multi-level groundwater sampling for contaminant plume delineation

    SciTech Connect

    Smuin, D.R.

    1995-12-01

    This paper describes the drilling and sampling methods used to delineate a groundwater contaminant plume at the Paducah Gaseous Diffusion Plant (PGDP) during the Groundwater Monitoring IV characterization. The project was unique in that it relied upon dual wall reverse circulation drilling instead of the traditional hollow stem auger method. The Groundwater Monitoring program sought to characterize the boundaries, both vertically and horizontally, of the northeast plume which contains both {sup 99}Tc and trichloroethene. This paper discusses the strengths and weaknesses of the drilling method used by investigators.

  1. Determination of the sources of nitrate contamination in karst springs using isotopic and chemical indicators

    Microsoft Academic Search

    S. V Panno; K. C Hackley; H. H Hwang; W. R Kelly

    2001-01-01

    The sources of nitrate (NO3?) in groundwater of the shallow karst aquifer in southwestern Illinois' sinkhole plain were investigated using chemical and isotopic techniques. The groundwater in this aquifer is an important source of potable water for about half of the residents of the sinkhole plain area. Previous work has shown that groundwater from approximately 18% of the wells in

  2. Intrinsic bioremediation of MTBE-contaminated groundwater at a petroleum-hydrocarbon spill site

    NASA Astrophysics Data System (ADS)

    Chen, K. F.; Kao, C. M.; Chen, T. Y.; Weng, C. H.; Tsai, C. T.

    2006-06-01

    An oil-refining plant site located in southern Taiwan has been identified as a petroleum-hydrocarbon [mainly methyl tert-butyl ether (MTBE) and benzene, toluene, ethylbenzene, and xylenes (BTEX)] spill site. In this study, groundwater samples collected from the site were analyzed to assess the occurrence of intrinsic MTBE biodegradation. Microcosm experiments were conducted to evaluate the feasibility of biodegrading MTBE by indigenous microorganisms under aerobic, cometabolic, iron reducing, and methanogenic conditions. Results from the field investigation and microbial enumeration indicate that the intrinsic biodegradation of MTBE and BTEX is occurring and causing the decrease in MTBE and BTEX concentrations. Microcosm results show that the indigenous microorganisms were able to biodegrade MTBE under aerobic conditions using MTBE as the sole primary substrate. The detected biodegradation byproduct, tri-butyl alcohol (TBA), can also be biodegraded by the indigenous microorganisms. In addition, microcosms with site groundwater as the medium solution show higher MTBE biodegradation rate. This indicates that the site groundwater might contain some trace minerals or organics, which could enhance the MTBE biodegradation. Results show that the addition of BTEX at low levels could also enhance the MTBE removal. No MTBE removal was detected in iron reducing and methanogenic microcosms. This might be due to the effects of low dissolved oxygen (approximately 0.3 mg/L) within the plume. The low iron reducers and methanogens (<1.8×103 cell/g of soil) observed in the aquifer also indicate that the iron reduction and methanogenesis are not the dominant biodegradation patterns in the contaminant plume. Results from the microcosm study reveal that preliminary laboratory study is required to determine the appropriate substrates and oxidation-reduction conditions to enhance the biodegradation of MTBE. Results suggest that in situ or on-site aerobic bioremediation using indigenous microorganisms would be a feasible technology to clean up this MTBE-contaminated site.

  3. 100-D Area In Situ Redox Treatability Test for Chromate-Contaminated Groundwater

    SciTech Connect

    Williams, Mark D.; Vermeul, Vincent R.; Szecsody, James E.; Fruchter, Jonathan S.

    2000-10-12

    A treatability test was conducted for the In Situ Redox Manipulation (ISRM) technology at the 100 D Area of the U. S. Department of Energy's Hanford Site. The target contaminant was dissolved chromate in groundwater. The ISRM technology creates a permeable subsurface treatment zone to reduce mobile chromate in groundwater to an insoluble form. The ISRM permeable treatment zone is created by reducing ferric iron to ferrous iron within the aquifer sediments, which is accomplished by injecting aqueous sodium dithionite into the aquifer and then withdrawing the reaction products. The goal of the treatability test was to create a linear ISRM barrier by injecting sodium dithionite into five wells. Well installation and site characterization activities began in spring 1997; the first dithionite injection took place in September 1997. The results of this first injection were monitored through the spring of 1998. The remaining four dithionite injections were carried out in May through July of 1998.These five injections created a reduced zone in the Hanford unconfined aquifer approximately 150 feet in length (perpendicular to groundwater flow) and 50 feet wide. The reduced zone extended over the thickness of the unconfined zone. Analysis of post-emplacement groundwater samples showed concentrations of chromate, in the reduced zone decreased from approximately 1.0 mg/L before the tests to below analytical detection limits (<0.007 mg/L). Chromate concentrations also declined in downgradient monitoring wells to as low as 0.020 mg/L. These data, in addition to results from pre-test reducible iron characterization, indicate the barrier should be effective for 20 to 25 years. The 100-D Area ISRM barrier is being expanded to a length of up to 2,300 ft to capture a larger portion of the chromate plume.

  4. Characterization of the methanotrophic bacterial community present in a trichloroethylene-contaminated subsurface groundwater site.

    PubMed Central

    Bowman, J P; Jiménez, L; Rosario, I; Hazen, T C; Sayler, G S

    1993-01-01

    Groundwater, contaminated with trichloroethylene (TCE) and tetrachloroethylene (PCE), was collected from 13 monitoring wells at Area M on the U.S. Department of Energy Savannah River Site near Aiken, S.C. Filtered groundwater samples were enriched with methane, leading to the isolation of 25 methanotrophic isolates. The phospholipid fatty acid profiles of all the isolates were dominated by 18:1 omega 8c (60 to 80%), a signature lipid for group II methanotrophs. Subsequent phenotypic testing showed that most of the strains were members of the genus Methylosinus and one isolate was a member of the genus Methylocystis. Most of the methanotroph isolates exhibited soluble methane monooxygenase (sMMO) activity. This was presumptively indicated by the naphthalene oxidation assay and confirmed by hybridization with a gene probe encoding the mmoB gene and by cell extract assays. TCE was degraded at various rates by most of the sMMO-producing isolates, whereas PCE was not degraded. Savannah River Area M and other groundwaters, pristine and polluted, were found to support sMMO activity when supplemented with nutrients and then inoculated with Methylosinus trichosporium OB3b. The maximal sMMO-specific activity obtained in the various groundwaters ranged from 41 to 67% compared with maximal rates obtained in copper-free nitrate mineral salts media. This study partially supports the hypothesis that stimulation of indigenous methanotrophic communities can be efficacious for removal of chlorinated aliphatic hydrocarbons from subsurface sites and that the removal can be mediated by sMMO. PMID:8368829

  5. Preliminary evaluation of ground-water contamination by coal-tar derivatives, St. Louis Park area, Minnesota

    USGS Publications Warehouse

    Hult, Marc F.; Schoenberg, Michael E.

    1984-01-01

    Operation of a coal-tar distillation and wood-preserving plant from 1918 to 1972 in St. Louis Park, a suburb of Minneapolis, Minn., resulted in ground-water contamination. This preliminary evaluation presents an overview of the problem based on the results of the first year (1979) of an ongoing study. By 1932, water in the Prairie du Chien-Jordan aquifer, the region's major source of ground water, was contaminated 3,500 feet from the plant. It seems that this early contamination of the aquifer resulted in part from the introduction of coal tar directly into a multiaquifer well on the plant site. The Prairie du Chien-Jordan aquifer underlies the area at depths of 250 to 500 feet and is overlain by two bedrock aquifers (Platteville and St. Peter), two confining beds (Glenwood and the basal part of St. Peter), and 70 to 100 feet of drift. The upper part of the aquifer (the Prairie du Chien Group) is carbonate rock having fracture and solution-channel permeability and low effective porosity. Contaminants in the Prairie du Chien Group can move more rapidly than those in drift and sandstone aquifers having intergranular permeability. The aquifer characteristics, the long contamination history, and seasonal potentiometric-surface fluctuations owing to heavy municipal and industrial withdrawals combine to create a complex distribution of coal-tar derivatives in the Prairie du Chien-Jordan aquifer. In addition, at least 25 ungrouted or partly cased wells in the area may permit contaminated water from near-surface aquifers to flow downward into deeper bedrock aquifers along or through the well bores. Where possible, such wells have been geophysically logged and inspected by downhole television. Flow rates of 20 to 150 gallons per minute from the Platteville and St. Peter aquifers to the Prairie du Chien-Jordan aquifer were observed in five of nine wells. The water was contaminated in four of the five wells. Drift materials on and south of the site have been contaminated by surface spills and by infiltration of contaminated process water. Near the contamination source, a hydrocarbon fluid phase is moving vertically downward relative to movement of the aqueous phase. Fluid pumped from an observation well in this area contained 6,000 milligrams per liter total organic carbon. Dissolved coal-tar constituents in the drift and the uppermost bedrock unit over most of the area, the Platteville aquifer, have moved at least 4,000 feet downgradient to a drift-filled bedrock valley. At the valley, it seems that the Platteville aquifer and the Glenwood confining bed have been removed by erosion and that contaminants with a concentration of approximately 2 milligrams per liter dissolved organic carbon are entering the underlying St. Peter aquifer. Chemical analyses of fluid pumped from observation wells suggest that soluble, low-molecular-weight compounds are moving preferentially through the drift and the Platteville aquifer.

  6. Development of HUMASORB{trademark}, a lignite derived humic acid for removal of metals and organic contaminants from groundwater

    SciTech Connect

    Sanjay, H.G.; Srivastava, K.C.; Walia, D.S.

    1995-12-31

    Heavy metal and organic contamination of surface and groundwater systems is a major environmental concern. The contamination is primarily due to improperly disposed industrial wastes. The presence of toxic heavy metal ions, volatile organic compounds (VOCs) and pesticides in water is of great concern and could affect the safety of drinking water. Decontamination of surface and groundwater can be achieved using a broad spectrum of treatment options such as precipitation, ion-exchange, microbial digestion, membrane separation, activated carbon adsorption, etc. The state of the art technologies for treatment of contaminated water however, can in one pass remediate only one class of contaminants, i.e., either VOCs (activated carbon) or heavy metals (ion exchange). This would require the use of at a minimum, two different stepwise processes to remediate a site. The groundwater contamination at different Department of Energy (DOE) sites (e.g., Hanford) is due to the presence of both VOCs and heavy metals. The two-step approach increases the cost of remediation. To overcome the sequential treatment of contaminated streams to remove both organics and metals, a novel material having properties to remove both classes of contaminants in one step is being developed as part of this project.

  7. Evaluation of an intrinsic and a specific vulnerability assessment method in comparison with groundwater salinisation and nitrate contamination levels in two agricultural regions in the south of Portugal

    Microsoft Academic Search

    T. Y. Stigter; L. Ribeiro; A. M. M. Carvalho Dill

    2006-01-01

    The applicability of two vulnerability assessment methods in evaluating the impact of agricultural activities on groundwater quality, is tested in two areas in the south of Portugal with modest results. Intensive citri- and horticulture require large amounts of fertiliser and water supplied by irrigation, which induces groundwater salinisation and contamination by nitrates. The degree of contamination varies highly within and

  8. Receptor Modeling for Contaminant Particle Source Apportionment in Clean Rooms

    Microsoft Academic Search

    Yi Tian; Pratim Biswas; Sotiris E. Pratsinis; Jin Jwang Wu

    1990-01-01

    Receptor modeling is used to apportion the contaminant particle concentrations among their sources in clean rooms through particle number concentration balances at various size intervals. The technique is demonstrated with optical particle counter data from an IBM clean room and a clean room at the University of Cincinnati. Quantitative contributions of two particulate sources to the aerosol concentration near wafer

  9. Application of electromagnetic techniques in survey of contaminated groundwater at an abandoned mine complex in southwestern Indiana, U.S.A.

    USGS Publications Warehouse

    Brooks, G.A.; Olyphant, G.A.; Harper, D.

    1991-01-01

    In part of a large abandoned mining complex, electromagnetic geophysical surveys were used along with data derived from cores and monitoring wells to infer sources of contamination and subsurface hydrologic connections between acidic refuse deposits and adjacent undisturbed geologic materials. Electrical resistivity increases sharply along the boundary of an elevated deposit of pyritic coarse refuse, which is highly contaminated and electrically conductive, indicating poor subsurface hydrologic connections with surrounding deposits of fine refuse and undisturbed glacial material. Groundwater chemistry, as reflected in values of specific conductance, also differs markedly across the deposit's boundary, indicating that a widespread contaminant plume has not developed around the coarse refuse in more than 40 yr since the deposit was created. Most acidic drainage from the coarse refuse is by surface runoff and is concentrated around stream channels. Although most of the contaminated groundwater within the study area is concentrated within the surficial refuse deposits, transects of apparent resistivity and phase angle indicate the existence of an anomalous conductive layer at depth (>4 m) in thick alluvial sediments along the northern boundary of the mining complex. Based on knowledge of local geology, the anomaly is interpreted to represent a subsurface connection between the alluvium and a flooded abandoned underground mine. ?? 1991 Springer-Verlag New York Inc.

  10. Geogenic sources of local arsenic enrichment in groundwater from northwestern Thuringia, Germany

    NASA Astrophysics Data System (ADS)

    Abratis, Michael; Viereck, Lothar

    2014-05-01

    Aqueous fluids migrating in the Earth's crust interact with the host rocks and partially take up their geochemical signatures. Mineralization and sometimes geogenic contamination of the groundwater may be the consequence: The aquifer systems of the Lower Triassic Buntsandstein Formation, an important source of drinking water in north-western Thuringia, and the Rotliegend Formation are locally affected by elevated arsenic concentrations. Data from water wells locally show arsenic concentrations above the limit value for drinking water (10 ?g/L). The regional distribution as well as lack of secondary vein mineralizations or anthropogenic sources within this area point to a geogenic stratibound source of arsenic. The average concentration of the toxic, carcinogenic trace element arsenic in rocks of Phanerozoic rocks in Germany range from 5 to 12 ?g/g for different lithologies, being generally higher in Variscan rocks. However, it can be several times enriched in certain sedimentary lithologies such as pelites and even more so in coal beds. In our present study we investigate all sequences of the Buntsandstein and Rotliegend Formation with their different lithologies in order to identify the relevant carriers of arsenic. Geochemical analyses on samples from selected drill cores and outcrops show arsenic of >50 ?g/g especially in carbonaceous sediment sections as well as in primarily gray-green lacustrine clay stones. Elevated arsenic concentrations seem to be related to lithofacies of lacustrine origin in the Buntsandstein and carbonaceous sediment sections in the Rotliegend. Aim of the current study is now to identify the appropriate synsedimentary mineral phases that incorporate arsenic and to identify the processes and conditions under which arsenic is mobilized from these phases and transferred into the groundwater.

  11. Sources and Relative Timing of Groundwater Recharge in Northwest India Using Environmental Isotopes

    NASA Astrophysics Data System (ADS)

    Rai, S. P.; Joshi, S. K.; Sinha, R.; Gupta, S.; Densmore, A. L.; Rawat, Y. S.; Shekhar, S.

    2014-12-01

    The Indo-Gangetic basin in northwest India is a major hotspot of groundwater depletion over the last four decades, with significant consequences for future agricultural productivity. However, little is known about groundwater dynamics in this region. We use environmental isotope analysis of rainfall, groundwater and surface water to characterize zones and sources of groundwater recharge in the Ghaggar basin lying between the Himalayan-fed Yamuna and Sutlej river systems. Around 700 groundwater samples were collected from 182 locations within the Ghaggar basin during pre- and post-monsoon periods of 2013. The ?18O values of river water vary from -7.3‰ to -5.3‰ and ?2H varies from -50.6‰ to -46.4‰, suggesting source of water from lower altitude. Depleted isotopic values of ?18O between -12.1‰ and -11.5‰, and ?2H between -79.1‰ and -74.9‰, are observed in canal water sourced from the Sutlej. The ?18O values of groundwater vary from -12.6‰ to -3.1‰ and ?2H from -84.8‰ to -28.6‰. Groundwater isotopic values fall on the LMWL, indicating local precipitation as the main recharge source, although a few depleted samples falling above the LMWL suggest local canal recharge. A key point in our data is the marked longitudinal as well as vertical variability in composition of groundwater samples reflecting differences in age and recharge sources. Longitudinal variability in groundwater is reflected from a much larger scatter in both ?18O and ?2H values for the downstream reaches compared to the upstream reaches, suggesting mixing of various sources of recharge. Also, groundwater in downstream reaches is saline or brackish with EC values of >4000 ?S/cm reflecting evaporation of irrigation water. Further, groundwater samples above 60 m bgl show tritium values in range of 1.88-8.0 TU indicating sub-modern to modern recharge whereas those below 60m bgl show a much lower values of 0.3-1.88 TU suggesting groundwater is sub-modern to older than 50 yrs. It indicates that replenishment of groundwater below 60 m bgl is very little. Stable isotope data also show that the shallow aquifers have a larger variability in both ?18O and ?2H values compared to those for the deeper aquifers. Such inhomogeneity in groundwater structure has important implications for sustainable groundwater management in this region

  12. Stimulating the In Situ Activity of Geobacter Species to Remove Uranium from the Groundwater of a Uranium-Contaminated Aquifer

    Microsoft Academic Search

    Robert T. Anderson; Helen A. Vrionis; Irene Ortiz-Bernad; Charles T. Resch; Philip E. Long; Richard Dayvault; Ken Karp; Sammy J. Marutzky; Donald R. Metzler; Aaron D. Peacock; David C. White; Mary Lowe; Derek R. Lovley

    2003-01-01

    The potential for removing uranium from contaminated groundwater by stimulating the in situ activity of dissimilatory metal-reducing microorganisms was evaluated in a uranium-contaminated aquifer located in Rifle, Colo. Acetate (1 to 3 mM) was injected into the subsurface over a 3-month period via an injection gallery composed of 20 injection wells, which was installed upgradient from a series of 15

  13. Permeable Adsorptive Barrier (PAB) for the remediation of groundwater simultaneously contaminated by some chlorinated organic compounds.

    PubMed

    Erto, A; Bortone, I; Di Nardo, A; Di Natale, M; Musmarra, D

    2014-07-01

    In this paper, a Permeable Reactive Barrier (PRB) made with activated carbon, namely a Permeable Adsorptive Barrier (PAB), is put forward as an effective technique for the remediation of aquifers simultaneously contaminated by some chlorinated organic compounds. A design procedure, based on a computer code and including different routines, is presented as a tool to accurately describe mass transport within the aquifer and adsorption/desorption phenomena occurring inside the barrier. The remediation of a contaminated aquifer near a solid waste landfill in the district of Napoli (Italy), where Tetrachloroethylene (PCE) and Trichloroethylene (TCE) are simultaneously present, is considered as a case study. A complete hydrological and geotechnical site characterization, as well as a number of dedicated adsorption laboratory tests for the determination of activated carbon PCE/TCE adsorption capacity in binary systems, are carried out to support the barrier design. By means of a series of numerical simulations it is possible to determine the optimal barrier location, orientation and dimensions. PABs appear to be an effective remediation tool for the in-situ treatment of an aquifer contaminated by PCE and TCE simultaneously, as the concentration of both compounds flowing out of the barrier is everywhere lower than the regulatory limits on groundwater quality. PMID:24747934

  14. Probability of nitrate contamination of recently recharged groundwaters in the conterminous United States.

    PubMed

    Nolan, Bernard T; Hitt, Kerie J; Ruddy, Barbara C

    2002-05-15

    A new logistic regression (LR) model was used to predict the probability of nitrate contamination exceeding 4 mg/L in predominantly shallow, recently recharged groundwaters of the United States. The new model contains variables representing (1) N fertilizer loading (p < 0.001), (2) percent cropland-pasture (p < 0.001), (3) natural log of human population density (p < 0.001), (4) percent well-drained soils (p < 0.001), (5) depth to the seasonally high water table (p < 0.001), and (6) presence or absence of unconsolidated sand and gravel aquifers (p = 0.002). Observed and average predicted probabilities associated with deciles of risk are well correlated (r2 = 0.875), indicating that the LR model fits the data well. The likelihood of nitrate contamination is greater in areas with high N loading and well-drained surficial soils over unconsolidated sand and gravels. The LR model correctly predicted the status of nitrate contamination in 75% of wells in a validation data set. Considering all wells used in both calibration and validation, observed median nitrate concentration increased from 0.24 to 8.30 mg/L as the mapped probability of nitrate exceeding 4 mg/L increased from < or =0.17 to >0.83. PMID:12038822

  15. Inhibition of Acetoclastic Methanogenesis in Crude Oil- and Creosote-Contaminated Groundwater

    USGS Publications Warehouse

    Warren, E.; Bekins, B.A.; Godsy, E.M.; Smith, V.K.

    2003-01-01

    The inhibition of acetoclastic methanogenesis in crude oil- and creosote-contaminated groundwater was studied. The crude oil and water-soluble components of creosote contributed to the inhibition of acetoclastic methanogens. Acetoclastic methanogenesis was much more susceptible to the toxic inhibition of crude oil and creosote than either hydrogen- or formate-utilizing methanogenesis. The effect of this toxic inhibition was apparent in the population of the methanogenic trophic groups near nonaqueous crude oil at the Bemidji, MN, site. At a crude oil-contaminated site, numbers of acetoclastic methanogens found close to crude oil were 100 times fewer than those of hydrogen- and formate-utilizing methanogens. In laboratory toxicity assays, crude oil collected from the site inhibited methane production from acetate but not from formate or hydrogen. Toxicity assays with aqueous creosote extract completely inhibited acetate utilization over the range of tested dilutions but only mildly affected formate and hydrogen utilization. Wastewater reactor studies indicated that this toxicity would result in a decrease in the biodegradation rate of contaminants at sites where toxic compounds are present.

  16. Preliminary Engineering Report contaminated groundwater seeps 317/319/ENE area

    SciTech Connect

    NONE

    1996-10-01

    When the Resource Conservation and Recovery Act Facility Investigation (RFI) in the 317/319/ENE Area of Argonne National Laboratory-East (ANL-E) was being completed, groundwater was discovered moving to the surface through a series of seeps. The seeps are located approximately 600 ft south of the ANL fence line in Waterfall Glen Forest Preserve. Samples of this water were collected and analyzed for selected parameters. Two of five seeps sampled were found to contain detectable levels of organic contaminants. Three chemical species were identified: chloroform (14-25 {mu}g/L), carbon tetrachloride (56-340 {mu}g/L), and tetrachloroethylene (3-6 {mu}g/L). The other seeps did not contain detectable levels of volatile organic compounds (VOCs). The water issuing from these two contaminated seeps flows into a narrow ravine, where it is visible as a trickle of water flowing through sand and gravel deposits on the floor of the ravine. Approximately 100-ft downstream of the seep area, the contaminated water is no longer visible, having drained back into the soil in the bed of the ravine. Figure 1 shows the location of the 317/319/ENE Area in relation to the ANL-E site and the Waterfall Glen Forest Preserve.

  17. Modelling the remediation of contaminated groundwater using zero-valent iron barrier

    SciTech Connect

    Kwong, S.; Small, J.; Tahar, B. [Nexia Solutions Ltd., Hinton House, Risley, Warrington, WA (United Kingdom)

    2007-07-01

    This paper presents results of modelling studies on remediation of groundwater contaminated with uranium using a zero-valent iron permeable reactive barrier (ZVI PRB) at the U.S. Oak Ridge Y-12 site that are used to establish modelling techniques that are of value to other sites such as in the UK. A systematic modelling methodology has been developed to study the problem by using a suite of modelling tools. Firstly a conceptual basis of the main chemical processes representing the remediation of uranium by the ZVI PRB is developed. Two main effects involving reduction and corrosion have been identified as being relevant for the remediation processes. These are then formulated and implemented using the reactive chemical model PHREEQC to provide underpinning chemical input parameters for subsequent reactive solute transport modelling using the TRAFFIC and PHAST codes. Initial results shows that modelling can be a very cost-effective means to study the hydrogeological and geochemical processes involved and to aid understanding of the remediation concept. The modelling approaches presented and lessons learnt are thought to be relevant to other cases of contaminated land study and are likely to be of value to site management concepts which consider on-site disposal of contaminated soils and materials. (authors)

  18. Steroid estrogens, nonylphenol ethoxylate metabolites, and other wastewater contaminants in groundwater affected by a residential septic system on cape cod, MA

    USGS Publications Warehouse

    Swartz, C.H.; Reddy, S.; Benotti, M.J.; Yin, H.; Barber, L.B.; Brownawell, Bruce J.; Rudel, R.A.

    2006-01-01

    Septic systems serve approximately 25% of U.S. households and may be an important source of estrogenic and other organic wastewater contaminants (OWC) to groundwater. We monitored several estrogenic OWC, including nonylphenol (NP), nonylphenol mono- and diethoxycarboxylates (NP1EC and NP2EC), the steroid hormones 17??-estradiol (E2), estrone (E1) and their glucuronide and sulfate conjugates, and other OWC such as methylene blue active substances (MBAS), caffeine and its degradation product paraxanthine, and two fluorescent whitening agents in a residential septic system and in downgradient groundwater. E1 and E2 were present predominantly as free estrogens in groundwater, and near-source groundwater concentrations of all OWC were highest in the suboxic to anoxic portion of the wastewater plume, where concentrations of most OWC were similar to those observed in the septic tank on the same day. NP and NP2EC were up to 6- to 30-fold higher, and caffeine and paraxanthine were each 60-fold lower than septic tank concentrations, suggesting net production and removal, respectively, of these constituents. At the most shallow, oxic depth, concentrations of all OWC except for NP2EC were substantially lower than in the tank and in deeper wells. Yet boron, specific conductance, and the sum of nitrate-and ammonia-nitrogen were highest at this shallow depth, suggesting preferential losses of OWC along the more oxic flow lines. As far as 6.0 m downgradient, concentrations of many OWC were within a factor of 2 of near-source concentrations. The results suggest that there is the potential for migration of these OWC, which are unregulated and not routinely monitored, in groundwater. ?? 2006 American Chemical Society.

  19. Hanford Site groundwater monitoring: Setting, sources and methods

    SciTech Connect

    M.J. Hartman

    2000-04-11

    Groundwater monitoring is conducted on the Hanford Site to meet the requirements of the Resource Conservation and Recovery Act of 1976 (RCRA); Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA); U.S. Department of Energy (DOE) orders; and the Washington Administrative Code. Results of monitoring are published annually (e.g., PNNL-11989). To reduce the redundancy of these annual reports, background information that does not change significantly from year to year has been extracted from the annual report and published in this companion volume. This report includes a description of groundwater monitoring requirements, site hydrogeology, and waste sites that have affected groundwater quality or that require groundwater monitoring. Monitoring networks and methods for sampling, analysis, and interpretation are summarized. Vadose zone monitoring methods and statistical methods also are described. Whenever necessary, updates to information contained in this document will be published in future groundwater annual reports.

  20. Groundwater

    NSDL National Science Digital Library

    Smoothstone

    This interactive Flash exercise explores groundwater and features models and animations for wet years and dry years as well as a diagram for groundwater terminology. This is a suitable overview or review for an introductory level course for high school or undergraduates.

  1. 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. PMID:18395311

  2. NATO/CCMS PILOT STUDY ON DEMONSTRATION OF REMEDIAL ACTIONTECHNOLOGIES FOR CONTAMINATED LAND AND GROUNDWATER - 1988ACTIVITIES

    EPA Science Inventory

    This paper describes the nature, structure and content of the NATOCommittee on the Challenges of Modern Society (CCMS) Pilot Study"Demonstration of Remedial Action Technologies for ContaminatedLand and Groundwater" and the associated CCMS Fellowship programme. To date, twelve pro...

  3. Preliminary conceptual study on impact of land reclamation on groundwater flow and contaminant migration in Penny's Bay

    E-print Network

    Jiao, Jiu Jimmy

    1 Preliminary conceptual study on impact of land reclamation on groundwater flow and contaminant A large-scale land reclamation project is now being carried out at Penny's Bay, Lantau Island, Hong Kong. The completed reclamation will provide 2.8 km2 of land for the construction of the new Hong Kong Disneyland

  4. Coupling 1D Monte-Carlo simulations and geostatistics to assess groundwater vulnerability to pesticide contamination on a regional scale

    Microsoft Academic Search

    Marc Soutter; André Musy

    1998-01-01

    A method to predict groundwater vulnerability to pesticide contamination on a regional scale has been developed and applied to a part of the upper Rhone river valley in Western Switzerland. Stochastic application of deterministic pesticide leaching models (Monte-Carlo), along with geostatistical interpolation techniques, were used to map both vulnerability levels and uncertainties. The various tested leaching models (numerical and analytical

  5. A simplified methodology for mapping groundwater vulnerability and contamination risk, and its first application in a tropical karst area, Vietnam

    Microsoft Academic Search

    Vu Thi Minh Nguyet; Nico Goldscheider

    2006-01-01

    A simplified methodology for mapping groundwater vulnerability and contamination risk is proposed, and the first application of the methodology, in a mountainous tropical karst area, is presented. The test site is the Tam Duong area, one of the poorest and remotest regions in northern Vietnam. The methodology requires a minimum of input data, which makes it particularly useful for developing

  6. Lack of promotional effects of groundwater contaminant mixtures on the induction of preneoplastic foci in rat liver

    Microsoft Academic Search

    Stephen A. Benjamin; Raymond S. H. Yang; John D. Tessari; Laura W. Chubb; Michael D. Brown; Charles E. Dean; Thomas J. Keefe

    1999-01-01

    F344 rats were exposed to drinking water mixtures of seven of the most common groundwater contaminants associated with hazardous waste sites [arsenic, benzene, chloroform, chromium, lead, phenol, and trichloroethylene (TCE)] as the full mixture or submixtures of the organic and\\/or inorganic chemicals. The lowest concentrations (1×) of the individual chemicals were environmentally realistic and below what would be expected to

  7. Ground-water resources and contamination at Kwajalein Island, Republic of the Marshall Islands, 1990-91

    USGS Publications Warehouse

    Hunt, Charles D., Jr.

    1996-01-01

    Kwajalein Island is the largest of the many low, sandy islets that form Kwajalein Atoll in the western North Pacific Ocean. Salinity and water-level surveys at exploratory monitoring wells in 1990 and 1991 delineated a freshwater lens nearly 40 feet thick floating on saltwater within the carbonate sand and gravel aquifer. A transition zone of mixture between the freshwater and saltwater is as thick as 90 feet. Maximum water-table height is only 1.5 feet above sea level. The freshwater lens thinned and thickened by 5 feet during the year-long field study in response to seasonal rainfall and pumping. Freshwater is produced by airstrip rain catchments and shallow, horizontal wells up to 1,400 feet long. Catchment and ground-water yields are roughly equal on average, but catchment is the principal source during the wet season, whereas the dry season requires sustained pumping. The salinity of pumped water has remained below drinking-water standards since wells were installed in 1971, except during the drought of 1983-84, the most severe drought in the rainfall record dating back to 1945. Wet-season rains at the end of the drought reduced salinity to low levels in just a few months. The operating history of the combined catchment/well water supply indicates that it is capable of producing at least 300,000 gallons per day in all but the driest years, and more in wet years. Several sites are contaminated by fuels, solvents, or metals, but most are at the periphery of the freshwater flow system where contaminants are carried toward the shore. However, three interior sites have greater potential to contaminate nearby water-supply wells.

  8. Health and socioeconomic effects of groundwater arsenic contamination in rural Bangladesh: new evidence from field surveys.

    PubMed

    Nahar, Nurun; Hossain, Faisal; Hossain, M Delawer

    2008-05-01

    This report discusses the health and socioeconomic problems that have recently emerged in the Bangladesh countryside because of arsenic contamination of the groundwater. A survey found that men in rural households are generally found to be more susceptible to arsenicosis than women. The survey also indicated that villagers with lower annual income are more likely to experience arsenicosis. About 60 percent of the respondents indicated a willingness to pay up to a dollar of their monthly income for safe water. More than 70 percent of women were found to be willing to walk for five minutes to collect safe water. Awareness campaigns conducted over the last decade seem to have been effective for villagers. Overall, findings from the survey paint a picture of a gradually evolving social and health scenario in rural Bangladesh that health officials must heed to safeguard the public health of the rural public. PMID:18517153

  9. Blast furnace residues for arsenic removal from mining-contaminated groundwater.

    PubMed

    Carrillo-Pedroza, Fco Raúl; Soria-Aguilar, Ma de Jesús; Martínez-Luevanos, Antonia; Narvaez-García, Víctor

    2014-01-01

    In this work, blast furnace (BF) residues were well characterized and then evaluated as an adsorbent material for arsenic removal from a mining-contaminated groundwater. The adsorption process was analysed using the theories of Freundlich and Langmuir. BF residues were found to be an effective sorbent for As (V) ions. The modelling of adsorption isotherms by empirical models shows that arsenate adsorption is fitted by the Langmuir model, suggesting a monolayer adsorption of arsenic onto adsorbents. Arsenate adsorption onto BF residue is explained by the charge density surface affinity and by the formation of Fe (II) and Fe (III) corrosion products onto BF residue particles. The results indicate that BF residues represent an attractive low-cost absorbent option for the removal of arsenic in wastewater treatment. PMID:25189836

  10. Sustainable remediation: electrochemically assisted microbial dechlorination of tetrachloroethene-contaminated groundwater

    PubMed Central

    Patil, Sayali S; Adetutu, Eric M; Rochow, Jacqueline; Mitchell, James G; Ball, Andrew S

    2014-01-01

    Microbial electric systems (MESs) hold significant promise for the sustainable remediation of chlorinated solvents such as tetrachlorethene (perchloroethylene, PCE). Although the bio-electrochemical potential of some specific bacterial species such as Dehalcoccoides and Geobacteraceae have been exploited, this ability in other undefined microorganisms has not been extensively assessed. Hence, the focus of this study was to investigate indigenous and potentially bio-electrochemically active microorganisms in PCE-contaminated groundwater. Lab-scale MESs were fed with acetate and carbon electrode/PCE as electron donors and acceptors, respectively, under biostimulation (BS) and BS-bioaugmentation (BS-BA) regimes. Molecular analysis of the indigenous groundwater community identified mainly Spirochaetes, Firmicutes, Bacteroidetes, and ? and ?-Proteobacteria. Environmental scanning electron photomicrographs of the anode surfaces showed extensive indigenous microbial colonization under both regimes. This colonization and BS resulted in 100% dechlorination in both treatments with complete dechlorination occurring 4 weeks earlier in BS-BA samples and up to 11.5 ?A of current being generated. The indigenous non-Dehalococcoides community was found to contribute significantly to electron transfer with ?61% of the current generated due to their activities. This study therefore shows the potential of the indigenous non-Dehalococcoides bacterial community in bio-electrochemically reducing PCE that could prove to be a cost-effective and sustainable bioremediation practice. PMID:24119162

  11. Risk of diarrhoea from shallow groundwater contaminated with enteropathogens in the Kathmandu Valley, Nepal.

    PubMed

    Shrestha, Sadhana; Haramoto, Eiji; Malla, Rabin; Nishida, Kei

    2015-03-01

    Shallow groundwater is the main water source among many alternatives in the Kathmandu Valley, Nepal, which has a rapidly growing population and intermittent piped water supply. Although human pathogens are detected in groundwater, its health effects are unclear. We estimated risk of diarrhoea from shallow groundwater use using quantitative microbial risk assessment. Escherichia coli, Giardia cyst and Cryptosporidium oocyst levels were analysed in dug and tube wells samples. E. coli concentrations were converted to those of enteropathogenic E. coli (EPEC). Risks from EPEC in dug wells and from Cryptosporidium and Giardia in both dug and tube wells were higher than the acceptable limit (<10?? infections/person-year) for both drinking and bathing exposures. Risk from protozoan enteropathogens increased the total risk 10,000 times, indicating that ignoring protozoans could lead to serious risk underestimation. Bathing exposure considerably increased risk, indicating that it is an important pathway. Point-of-use (POU) water treatment decreased the risk six-fold and decreased risk overestimation. Because removal efficiency of POU water treatment has the largest impact on total risk, increasing the coverage and efficiency of POU water treatment could be a practical risk management strategy in the Kathmandu Valley and similar settings. PMID:25719484

  12. Sources and Movement of Saline Groundwater in a Coastal Aquifer, Southern California, USA

    NASA Astrophysics Data System (ADS)

    Anders, R.; Stolp, B. J.; Danskin, W. R.

    2014-12-01

    Development of local groundwater resources in coastal areas is limited by the presence of saline groundwater. For a study in the San Diego area, a geochemical approach was used to investigate the sources and movement of saline groundwater in the coastal aquifer. Chemical and isotopic data were collected from multiple-depth monitoring-well sites near the San Diego coastline at discrete intervals to depths of more than 650 meters. The groundwater samples were analyzed for major and minor ions, the stable isotopes of hydrogen, oxygen, and strontium, and radioactive isotopes of tritium and carbon-14. Each chemical and isotopic tracer preserves some aspect of the hydrologic history of the groundwater ranging from the chemical characteristics (major and minor ions), to the source of water (stable isotopes of oxygen and hydrogen), to the types of rock encountered in the groundwater flow system (strontium isotopes), to time-since-recharge (tritium and carbon-14). By using sodium-to-calcium mass ratios, in combination with the isotopic data, the occurrence of saline groundwater as a result of seawater intrusion was distinguishable from groundwater in a previously-saline aquifer that has been "flushed" by fresher continental recharge. The systematic analysis of these tracers indicate that the sources and movement of saline groundwater in the coastal San Diego area are dominated by: 1) regional flow of higher-elevation precipitation that recharged many thousands of years ago along deep flowpaths; 2) recharge of local precipitation in relatively shallower portions of the flow system; and 3) intrusion of seawater that primarily entered the aquifer during pre-modern times. Use of multiple chemical and isotopic tracers provides unique insight regarding the processes affecting groundwater quality, enabling local water agencies to assess the groundwater resources in the coastal aquifer and begin to reduce the area's reliance on imported water.

  13. Groundwater quality assessment for the Upper East Fork Poplar Creek Hydrogeologic Regime at the Y-12 Plant. 1991 groundwater quality data and calculated rate of contaminant migration

    SciTech Connect

    Not Available

    1992-02-01

    This report contains groundwater quality data obtained during the 1991 calendar year at several waste management facilities and petroleum fuel underground storage tank (UST) sites associated with the Y-12 Plant. These sites are within the Upper East Fork Poplar Creek Hydrogeologic Regime (UEFPCHR), which is one of three regimes defined for the purposes of groundwater and surface-water quality monitoring and remediation. This report was prepared for informational purposes. Included are the analytical data for groundwater samples collected from selected monitoring wells during 1991 and the results for quality assurance/quality control (QA/QC) samples associated with each groundwater sample. This report also contains summaries of selected data, including ion-charge balances for each groundwater sample, a summary of analytical results for nitrate (a principle contaminant in the UEFPCHR), results of volatile organic compounds (VOCs) analyses validated using the associated QA/QC sample data, a summary of trace metal concentrations which exceeded drinking-water standards, and a summary of radiochemical analyses and associated counting errors.

  14. 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. PMID:22002748

  15. Enrichment of specific protozoan populations during in situ bioremediation of uranium-contaminated groundwater

    SciTech Connect

    Holmes, Dawn; Giloteaux, L.; Williams, Kenneth H.; Wrighton, Kelly C.; Wilkins, Michael J.; Thompson, Courtney A.; Roper, Thomas J.; Long, Philip E.; Lovley, Derek

    2013-07-28

    The importance of bacteria in the anaerobic bioremediation of groundwater polluted with organic and/or metal contaminants is well-recognized and in some instances so well understood that modeling of the in situ metabolic activity of the relevant subsurface microorganisms in response to changes in subsurface geochemistry is feasible. However, a potentially significant factor influencing bacterial growth and activity in the subsurface that has not been adequately addressed is protozoan predation of the microorganisms responsible for bioremediation. In field experiments at a uranium-contaminated aquifer located in Rifle, CO, acetate amendments initially promoted the growth of metal-reducing Geobacter species followed by the growth of sulfate-reducers, as previously observed. Analysis of 18S rRNA gene sequences revealed a broad diversity of sequences closely related to known bacteriovorous protozoa in the groundwater prior to the addition of acetate. The bloom of Geobacter species was accompanied by a specific enrichment of sequences most closely related to the amoeboid flagellate, Breviata anathema, which at their peak accounted for over 80% of the sequences recovered. The abundance of Geobacter species declined following the rapid emergence of B. anathema. The subsequent growth of sulfate-reducing Peptococcaceae was accompanied by another specific enrichment of protozoa, but with sequences most similar to diplomonadid flagellates from the family Hexamitidae, which accounted for up to 100% of the sequences recovered during this phase of the bioremediation. These results suggest a prey-predator response with specific protozoa responding to increased availability of preferred prey bacteria. Thus, quantifying the influence of protozoan predation on the growth, activity, and composition of the subsurface bacterial community is essential for predictive modeling of in situ uranium bioremediation strategies.

  16. Assessment of ground-water contamination near Lantana landfill, Southeast Florida

    USGS Publications Warehouse

    Russell, G.M.; Higer, A.L.

    1988-01-01

    The Lantana landfill located in Palm Beach County rises 40 to 50 feet above normal ground level and consists of about 250 acres of compacted garbage and trash, some below the water table. Surface-resistivity measurements and water-quality analyses indicate a contaminant plume along the eastern perimeter of the landfill that has migrated about 300 feet eastward toward an adjacent lake. Concentrations of chloride, ammonia, and nitrate were elevated within the plume. The surficial aquifer consists primarily of sand from 0 to about 68 feet, and sand interbedded with sandstone and limestone from 68 to 220 feet. A slight hydraulic gradient exists, indicating ground-water movement from the landfill toward a lake to the east. Analyses of geoelectric, lithologic, and water-quality data indicate that surface geophysical techniques were successful in determining the areal and vertical extent of leachate migration at this location.The Lantana landfill located in Palm Beach County rises 40 to 50 feet above normal ground level and consists of about 250 acres of compacted garbage and trash, some below the water table. Surface-resistivity measurements and water-quality analyses indicate a contaminant plume along the eastern perimeter of the landfill that has migrated about 300 feet eastward toward an adjacent lake. Concentrations of chloride, ammonia, and nitrate were elevated within the plume. The surficial aquifer consists primarily of sand from 0 to about 68 feet, and sand interbedded with sandstone and limestone from 68 to 220 feet. A slight hydraulic gradient exists, indicating ground-water movement from the landfill toward a lake to the east. Analyses of geoelectric, lithologic, and water-quality data indicate that surface geophysical techniques were successful in determining the areal and vertical extent of leachate migration at this location.

  17. Hydrogeology, water quality, and potential for contamination of the Upper Floridan aquifer in the Silver Springs ground-water basin, central Marion County, Florida

    USGS Publications Warehouse

    Phelps, G.G.

    1994-01-01

    The Upper Floridan aquifer, composed of a thick sequence of very porous limestone and dolomite, is the principal source of water supply in the Silver Springs ground-water basin of central Marion County, Florida. The karstic nature of the local geology makes the aquifer susceptible to contaminants from the land surface. Contaminants can enter the aquifer by seepage through surficial deposits and through sinkholes and drainage wells. Potential contaminants include agricultural chemicals, landfill leachates and petroleum products from leaking storage tanks and accidental spills. More than 560 sites of potential contamination sources were identified in the basin in 1990. Detailed investigation of four sites were used to define hydrologic conditions at representative sites. Ground-water flow velocities determined from dye trace studies ranged from about 1 foot per hour under natural flow conditions to about 10 feet per hour under pumping conditions, which is considerably higher than velocities estimated using Darcy's equation for steady-state flow in a porous medium. Water entering the aquifer through drainage wells contained bacteria, elevated concentrations of nutrients, manganese and zinc, and in places, low concentrations of organic compounds. On the basis of results from the sampling of 34 wells in 1989 and 1990, and from the sampling of water entering the Upper Floridan aquifer through drainage wells, there has been no widespread degradation of water quality in the study area. In an area of karst, particularly one in which fracture flow is significant, evaluating the effects from contaminants is difficult and special care is required when interpolating hydrogeologic data from regional studies to a specific. (USGS)

  18. Development of two computerized methods to evaluate the certainty and the contamination risk indexes for groundwater vulnerability assessment

    SciTech Connect

    Cremonini, M.G.; Pittaluga, F.; Pedone, R.; Lombardo, P.

    1998-07-01

    Two simple and easily implementable computerized methods have been developed to (1) evaluate the level of certainty connected with the data quality used to prepare groundwater vulnerability maps, and (2) evaluate the derived risk increment due to both the reliability level of the vulnerability assessment and the impact of potential contaminant sources. Two specific criteria have therefore been developed based on the map overlay and index methods: the certainty index and the risk index. Input data for the certainty index are vulnerability assessment data quality (in term of precision, accuracy, completeness and representativeness), quantity and age; such input data are combined to evaluate the certainty index to inform on the reliability level of the produced vulnerability map for a given area. The risk index is based on a real distribution of potential pollution sources; input data are prepared according to a standardized system of classification and a score, derived from the anthropic presence/activities and land use, it obtained for each site. This score, combined with both the vulnerability evaluation and its certainty level, contributes to the computation of a final integrated risk index.

  19. Bacterial source tracking and shellfish contamination in a coastal catchment.

    PubMed

    Geary, P M; Davies, C M

    2003-01-01

    Introduced pathogens from faecal material can make their way into the aquatic environment from a number of catchment sources. These sources typically include sewage outfalls, seepage from septic tanks, and urban and agricultural runoff. Shellfish as filter feeders are particularly susceptible to contamination in faecally contaminated waters and a range of microbiological indicators have been developed to assess the levels of contamination and likely risks to public health (Hackney and Pierson, 1994). This paper outlines the application of bacterial source tracking (BST) in a shellfish growing area in part of the Port Stephens estuary along the NSW north coast. The approach is based on the premise that bacterial isolates from different faecal sources will have significantly different resistance patterns to the battery of antibiotics and concentrations tested. Faecal streptococci (FS) were isolated from several possible faecal sources: beef and dairy cattle, chickens and humans. The resistance patterns of these isolates to four different concentrations of four antibiotics were compared to those of FS isolates obtained from samples collected upstream and in the vicinity of the oyster leases. Discriminant analysis was performed using the patterns from the known source isolates and the rate of correct classification was determined for each source. The predictive function of discriminant analysis was then used to determine the most probable source of each of the unknown isolates from Tilligerry Creek, the drainage channels to the estuary, and the shellfish leases. Preliminary results are presented here and suggest that there is no single significant source of faecal contamination, rather there are contributions from a range of sources. The findings may have implications for the ways in which land use activities and catchments are managed in similar estuarine locations with a shellfish industry. PMID:12793667

  20. Application of geostatistical inverse modeling to contaminant source identification at Dover AFB, Delaware

    Microsoft Academic Search

    Anna M. Michalak; Peter K. Kitanidis

    2004-01-01

    Analysis of subsurface soil cores from the site of a field-scale groundwater remediation experiment at Dover Air Force Base, Delaware, has revealed that tetrachloroethene and trichloroethene contamination extends into an aquitard underlying a groundwater aquifer. Geostatistical inverse modeling is used to make inferences regarding the historical concentration conditions in the overlying aquifer. Because geostatistical inverse modeling is a stochastic approach,

  1. Subsurface characterization of groundwater contaminated by landfill leachate using microbial community profile data and a nonparametric decision-making process

    NASA Astrophysics Data System (ADS)

    Pearce, Andrea R.; Rizzo, Donna M.; Mouser, Paula J.

    2011-06-01

    Microbial biodiversity in groundwater and soil presents a unique opportunity for improving characterization and monitoring at sites with multiple contaminants, yet few computational methods use or incorporate these data because of their high dimensionality and variability. We present a systematic, nonparametric decision-making methodology to help characterize a water quality gradient in leachate-contaminated groundwater using only microbiological data for input. The data-driven methodology is based on clustering a set of molecular genetic-based microbial community profiles. Microbes were sampled from groundwater monitoring wells located within and around an aquifer contaminated with landfill leachate. We modified a self-organizing map (SOM) to weight the input variables by their relative importance and provide statistical guidance for classifying sample similarities. The methodology includes the following steps: (1) preprocessing the microbial data into a smaller number of independent variables using principal component analysis, (2) clustering the resulting principal component (PC) scores using a modified SOM capable of weighting the input PC scores by the percent variance explained by each score, and (3) using a nonparametric statistic to guide selection of appropriate groupings for management purposes. In this landfill leachate application, the weighted SOM assembles the microbial community data from monitoring wells into groupings believed to represent a gradient of site contamination that could aid in characterization and long-term monitoring decisions. Groupings based solely on microbial classifications are consistent with classifications of water quality from hydrochemical information. These microbial community profile data and improved decision-making strategy compliment traditional chemical groundwater analyses for delineating spatial zones of groundwater contamination.

  2. New evaluation scheme for two-dimensional isotope analysis to decipher biodegradation processes: application to groundwater contamination by MTBE.

    PubMed

    Zwank, Luc; Berg, Michael; Elsner, Martin; Schmidt, Torsten C; Schwarzenbach, René P; Haderlein, Stefan B

    2005-02-15

    Compound-specific analysis of stable carbon and hydrogen isotopes was used to assess the fate of the gasoline additive methyl tert-butyl ether (MTBE) and its major degradation product tert-butyl alcohol (TBA) in a groundwater plume at an industrial disposal site. We present a novel approach to evaluate two-dimensional compound-specific isotope data with the potential to identify reaction mechanisms and to quantify the extent of biodegradation at complex field sites. Due to the widespread contaminant plume, multiple MTBE sources, the presence of numerous other organic pollutants, and the complex biogeochemical and hydrological regime atthe site, a traditional mass balance approach was not applicable. The isotopic composition of MTBE steadily changed from the source regions along the major contaminant plume (-26.4% to +40.0% (carbon); -73.1% to +60.3% (hydrogen)) indicating substantial biodegradation. Constant carbon isotopic signatures of TBA suggest the absence of TBA degradation at the site. Published carbon and hydrogen isotope fractionation data for biodegradation of MTBE under oxic and anoxic conditions, respectively, were examined and used to determine both the nature and the extent of in-situ biodegradation along the plume(s). The coupled evaluation of two-dimensional compound-specific isotope data explained both carbon and hydrogen fractionation data in a consistent way and indicate anaerobic biodegradation of MTBE along the entire plume. A novel scheme to reevaluate empiric isotopic enrichment factors (epsilon) in terms of theoretically based intrinsic carbon (12k/13k) and hydrogen (1k/2k) kinetic isotope effects (KIE) is presented. Carbon and hydrogen KIE values, calculated for different potential reaction mechanisms, imply that anaerobic biodegradation of MTBE follows a SN2-type reaction mechanism. Furthermore, our data suggest that additional removal process(es) such as evaporation contributed to the overall MTBE removal along the plume, a phenomenon that might be significant also for other field sites at tropic or subtropic climates with elevated groundwater temperatures (25 degrees C). PMID:15773473

  3. Application of inverse methods to contaminant source identification from aquitard diffusion profiles at Dover AFB, Delaware

    Microsoft Academic Search

    Chongxuan Liu; William P. Ball

    1999-01-01

    This paper presents a refinement and expansion of our previously described efforts to estimate contaminant plume history from observed contaminant concentrations within a low-permeability aquitard at the site of a field-scale groundwater remediation experiment at Dover Air Force Base. At this site, a two-layer aquitard has been contaminated with tetrachloroethene and trichloroethene through diffusive mass transfer from an overlying contaminated

  4. Occurrence of atrazine and degradates as contaminants of subsurface drainage and shallow groundwater

    SciTech Connect

    Jayachandran, K.; Steinheimer, T.R.; Moorman, T.B. [National Soil Tilth Lab., Ames, IA (United States)

    1994-03-01

    Atrazine is a commonly used herbicide in corn (Zea mays L.) growing areas of the USA. Because of its heavy usage, moderate persistence, and mobility in soil, monitoring of atrazine movement under field conditions is essential to assess its potential to contaminate groundwater. Concentrations of atrazine, deisopropylatrazine (DIA), and deethlatraaine (DEA) were measured in subsurface drainage and shallow groundwater beneath continuous, no-till corn. Water samples were collected from the subsurface drain (tile) outlets and suction lysimeters in the growing seasons of 1990 and 1991, and analyzed for atrazine and two principle degradates won solid-phase extraction and HPLC. In 1990, atrazine concentration ranged from 1.3 to 5.1{mu}g L{sup -1} in tile-drain water and from 0.5 to 20.5 {mu}g L{sup -1} in lysimeter water. In general, concentrations of parent and degradates in solution were atrazine > DEA > DIA. Lesser levels of atrazine were measured in 1991 from Plots 2 and 4; however, greater concentrations of atrazine (6.0-8.4 {mu}g L{sup -1}) were measured from plot 5. Throughout the two growing seasons, atrazine concentration in Plot 5 tile-drain water was greater than that of Plots 2 and 4, suggesting a preferential movement of atrazine. Concentrations of DIA and DEA ranged from 0.1 to 2.2 and 0.9 to 3.2 {mu}g L{sup -1} respectively, indicating that the degradation products by themselves or in combination with parent atrazine can exceed the maximum contaminant level (mcl) of 3 {mu}g L{sup -1} even though atrazine by itself may be <3 {mu}g L{sup -1}. The deethylatrazine-to-atrazine ratio (DAR) is an indicator of residence time in soil during transport of atrazine to groundwater. In Plots 2 and 4, DAR values for tile-drain water ranged from 0.43 to 2.70 and 0.50 to 2.66 respectively. By comparison, a DAR of 0.38 to 0.60 was observed in Plot 5, suggesting less residence time in the soil. 38 refs., 5 figs., 4 tabs.

  5. LINEAR MODELS FOR MANAGING SOURCES OF GROUNDWATER POLLUTION.

    USGS Publications Warehouse

    Gorelick, Steven M.; Gustafson, Sven-Ake

    1984-01-01

    Mathematical models for the problem of maintaining a specified groundwater quality while permitting solute waste disposal at various facilities distributed over space are discussed. The pollutants are assumed to be chemically inert and their concentrations in the groundwater are governed by linear equations for advection and diffusion. The aim is to determine a disposal policy which maximises the total amount of pollutants released during a fixed time T while meeting the condition that the concentration everywhere is below prescribed levels.

  6. 1. Layers of soil, sand and rocks that store groundwater. 5. To contaminate, to become unclean.

    E-print Network

    Bashir, Rashid

    for groundwater is ________. 3. The stage of the water cycle when water changes from a liquid to a vapor. 4 of the water cycle when water soaks into the soil. 11. The movement of water underground is called groundwater _________. Water Cycle Crossword From The Groundwater Foundation. Learn more at www.groundwater.org. 1 2 3 4 5 7 10

  7. Comparison of some parallel Krylov solvers for large scale groundwater contaminant transport simulations

    SciTech Connect

    Mahinthakumar, G. [Oak Ridge National Lab., TN (United States). Center for Computational Sciences; Saied, F.; Valocchi, A.J. [Univ. of Illinois, Urbana, IL (United States)

    1997-03-01

    Some popular iterative solvers for non-symmetric systems arising from the finite-element discretization of three-dimensional groundwater contaminant transport problem are implemented and compared on distributed memory parallel platforms. This paper attempts to determine which solvers are most suitable for the contaminant transport problem under varied conditions for large scale simulations on distributed parallel platforms. The original parallel implementation was targeted for the 1024 node Intel paragon platform using explicit message passing with the NX library. This code was then ported to SGI Power Challenge Array, Convex Exemplar, and Origin 2000 machines using an MPI implementation. The performance of these solvers is studied for increasing problem size, roughness of the coefficients, and selected problem scenarios. These conditions affect the properties of the matrix and hence the difficulty level of the solution process. Performance is analyzed in terms of convergence behavior, overall time, parallel efficiency, and scalability. The solvers that are presented are BiCGSTAB, GMRES, ORTHOMIN, and CGS. A simple diagonal preconditioner is used in this parallel implementation for all the methods. The results indicate that all methods are comparable in performance with BiCGSTAB slightly outperforming the other methods for most problems. The authors achieved very good scalability in all the methods up to 1024 processors of the Intel Paragon XPS/150. They demonstrate scalability by solving 100 time steps of a 40 million element problem in about 5 minutes using either BiCGSTAB or GMRES.

  8. Optimization-based multicriteria decision analysis for identification of desired petroleum-contaminated groundwater remediation strategies.

    PubMed

    Lu, Hongwei; Feng, Mao; He, Li; Ren, Lixia

    2015-06-01

    The conventional multicriteria decision analysis (MCDA) methods used for pollution control generally depend on the data currently available. This could limit their real-world applications, especially where the input data (e.g., the most cost-effective remediation cost and eventual contaminant concentration) might vary by scenario. This study proposes an optimization-based MCDA (OMCDA) framework to address such a challenge. It is capable of (1) capturing various preferences of decision-makers, (2) screening and analyzing the performance of various optimized remediation strategies under changeable scenarios, and (3) compromising incongruous decision analysis results. A real-world case study is employed for demonstration, where four scenarios are considered with each one corresponding to a set of weights representative of the preference of the decision-makers. Four criteria are selected, i.e., optimal total pumping rate, remediation cost, contaminant concentration, and fitting error. Their values are determined through running optimization and optimization-based simulation procedures. Four sets of the most desired groundwater remediation strategies are identified, implying specific pumping rates under varied scenarios. Results indicate that the best action lies in groups 32 and 16 for the 5-year, groups 49 and 36 for the 10-year, groups 26 and 13 for the 15-year, and groups 47 and 13 for the 20-year remediation. PMID:25613797

  9. Treatment of low-level explosives and solvents contaminated groundwater using advanced oxidation processes

    SciTech Connect

    Zappi, M.; Toro, E. [USAE Waterways Experiment Station, Vicksburg, MS (United States); Kodukula, P. [Woodward-Cycle, Overland Park, KS (United States)] [and others

    1995-12-31

    This study focused on the evaluation of advanced oxidation processes (AOPs) as treatment for groundwater contaminated with organics at a former US Department of Defense facility. The primary contaminants targeted for treatment were trichloroethene (TCE) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Four candidate AOPs were evaluated: photolysis of hydrogen peroxide (HO) using light emitted by a medium pressure mercury vapor ultraviolet lamp (MPUV-HP), photolysis of ozone with light emitted from a low pressure mercury vapor ultraviolet lamp (LPUV-OZ), photolysis of HO with light emitted from a low pressure mercury vapor ultraviolet lamp (LPUV-HP), and peroxone. The results of the experiments in 1-liter, glass reactors indicated that TCE could be removed to within target goals by all candidate AOPs within 10 minutes of treatment. Peroxone systems had the poorest removal rates. There appears to be a distinct advantage to adding 100 milligram/l of HO rather than 10 milligram/l. The photo-based systems met treatment goals within 20 minutes of treatment; however, there were distinct differences in system performance. The LPUV-HP system had the poorest removal rate due the the narrow ultraviolet spectra emitted and the low adsorption of HO within this band. The MPUV lamp, in comparison, reducted treatment times by over 300 percent.

  10. Autotrophic, hydrogen-oxidizing, denitrifying bacteria in groundwater, potential agents for bioremediation of nitrate contamination

    USGS Publications Warehouse

    Smith, R.L.; Ceazan, M.L.; Brooks, M.H.

    1994-01-01

    Addition of hydrogen or formate significantly enhanced the rate of consumption of nitrate in slurried core samples obtained from an active zone of denitrification in a nitrate-contaminated sand and gravel aquifer (Cape Cod, Mass.). Hydrogen uptake by the core material was immediate and rapid, with an apparent K(m) of 0.45 to 0.60 ??M and a V(max) of 18.7 nmol cm-3 h-1 at 30??C. Nine strains of hydrogen-oxidizing denitrifying bacteria were subsequently isolated from the aquifer. Eight of the strains grew autotrophically on hydrogen with either oxygen or nitrate as the electron acceptor. One strain grew mixotrophically. All of the isolates were capable of heterotrophic growth, but none were similar to Paracoccus denitrificans, a well-characterized hydrogen-oxidizing denitrifier. The kinetics for hydrogen uptake during denitrification were determined for each isolate with substrate depletion progress curves; the K(m)s ranged from 0.30 to 3.32 ??M, with V(max)s of 1.85 to 13.29 fmol cell-1 h-1. Because these organisms appear to be common constituents of the in situ population of the aquifer, produce innocuous end products, and could be manipulated to sequentially consume oxygen and then nitrate when both were present, these results suggest that these organisms may have significant potential for in situ bioremediation of nitrate contamination in groundwater.

  11. Long-Term Fate of Organic Micropollutants in Sewage-Contaminated Groundwater

    USGS Publications Warehouse

    Barber, L.B., II; Schroeder, M.P.; LeBlanc, D.R.

    1988-01-01

    Disposal of secondary sewage effluent by rapid infiltration has produced a plume of contaminated groundwater over 3500 m long near Falmouth, MA. Approximately 50 volatile organic compounds were detected and identified in the plume, at concentrations ranging from 10 ng/L to 500 ??g/L, by closed-loop stripping and purge- and-trap in conjuction with gas chromatography-mass spectrometry. The dominant contaminants were di-, tri- and tetrachloroethene, o- and p-dichlorobenzene, C1 to C6 alkylbenzenes, 2,6-di-tert-butylbenzoquinone, and several isomers of p-nonylphenol. The chloroethenes and chlorobenzenes had the same general distribution as chloride and boron and appear to be transported with little retardation. Less soluble compounds, such as nonylphenol and di-tert-butylbenzoquinone, appear to be retarded during subsurface transport by sorption processes. Although biodegradation of labile organic compounds occurs near the infiltration beds, many trace compounds, including chlorinated benzenes, alkylbenzenes, and aliphatic hydrocarbons, have persisted for more than 30 years in the aquifer.

  12. Rapidly locating sources and predicting contaminant dispersion in buildings

    Microsoft Academic Search

    Michael D. Sohn; Pamela Reynolds; Ashok J. Gadgil; Richard G. Sextro

    2002-01-01

    Contaminant releases in or near a building can lead to significant human exposures unless prompt response measures are taken. However, selecting the proper response depends in part on knowing the source locations, the amounts released, and the dispersion characteristics of the pollutants. We present an approach that estimates this information in real time. It uses Bayesian statistics to interpret measurements

  13. Chemical Fate of Contaminants in the Environment: Chlorinated Hydrocarbons in the Groundwater

    SciTech Connect

    Truhlar, Donald G.; Cramer, Christopher; Gao, Jiali; Garrett, Bruce C.; Dupuis, Michel; Straatsma, TP; Morokuma, Keiji; Dunning, Thomas H.; Borisov, Yurii A.; Arcia, Edgar E.; Thompson, Jacob S.

    2006-09-21

    Chlorinated hydrocarbons (CHCs) are the most common contaminant found at hazardous waste sites and are the most prevalent contaminants on U.S. Department of Energy (DOE) weapons production sites. Many of the CHCs are either known or suspected carcinogens and thus pose health risks to the public and/or site workers. Unlike simple hydrocarbons, CHCs are resistant to biodegradation, but can degrade by abiotic processes such as hydrolysis, nucleophilic substitution, and dehydrochlorination. Unfortunately, few studies of the reactions of chlorinated hydrocarbons have been reported in literature, and disagreement still exists about the mechanisms and rates of many of the key reactions. In this work, we modeled the reactions involved in the degradation of CHCs in the groundwater. The goals of the research proposed are: • development of a computational approach that will allow reaction pathways and rate constants to be accurately calculated • development of more approximate approaches, evaluated against the more accurate approach, which will lay the groundwork for exploratory studies of more complex CHCs • application of these approaches to study the degradation pathways of CHCs in aqueous liquids • application of the more approximate approaches to study the mechanism of forming complex CHC polychlorinated benzene compounds and dioxins. We examined elementary reactions involved in the aqueous-phase chemistry of chlorinated methanes and ethylenes in an attempt to obtain a detailed understanding of the abiotic processes involved in the degradation of this important class of contaminants. We began by studying the reactions of CHnCl(4-n) and C2HnCl(4-n) with OH¯, as these are thought to be the dominant processes involved in the degradation of these chlorinated species. We used state-of-the-art theoretical techniques to model the elementary reactions of CHCs important in the groundwater. We employed high-accuracy electronic structure methods (e.g., perturbation theory and coupled cluster methods with correlation-consistent basis sets) to determine the energies of the various stable species, intermediates, and transition states involved in the elementary reactions of CHCs. Effects of solvation on the reaction energetics were studied by including small numbers of solvent molecules (microsolvation). Our own N-layered molecular orbital + molecular mechanics (ONIOM) method was used because it allows the number of solvent molecules to be increased, and hybrid quantum mechanical/molecular mechanics (QM/MM) methods and continuum solvation models were used to estimate the effects of bulk solvation. Rate constants for the gas-phase, microsolvated, and bulk-phase reactions were computed using variational transition state theory (VTST).

  14. Field scale characterization and modeling of contaminant release from a coal tar source zone

    NASA Astrophysics Data System (ADS)

    D'Affonseca, Fernando M.; Blum, Philipp; Finkel, Michael; Melzer, Reiner; Grathwohl, Peter

    2008-11-01

    A coal tar contaminated site was characterized using traditional and innovative investigation methods. A careful interpretation of hydrogeological and hydrogeochemical data allowed for the conceptualization of the heterogeneous coal tar distribution in the subsurface. Past and future contaminant release from the source zone was calculated using a modeling framework consisting of a three-dimensional steady-state groundwater flow model (MODFLOW) and two hydrogeochemical models (MIN3P). Computational time of long-term simulations was reduced by simplifying the coal tar composition using 3 composite and 2 individual constituents and sequential application of a 2D centerline model (for calibration and predictions) and a 3D model (only for predictions). Predictions were carried out for a period of 1000 years. The results reveal that contaminant mass flux is governed by the geometry of zones containing residual coal tar, amount of coal tar, its composition and the physicochemical properties of the constituents. The long-term predictions made using the 2D model show that even after 1000 years, source depletion will be small with respect to phenanthrene, 89% of initial mass will be still available, and for the moderately and sparingly soluble composite constituents, 60% and 98%, respectively.

  15. Final report : results of the 2005 investigation of contaminant sources at Agra, Kansas.

    SciTech Connect

    LaFreniere, L. M.

    2006-08-24

    The 2005 investigation of contaminant sources at Agra, Kansas, was conducted at the request of the Kansas Department of Health and Environment (KDHE; Gotto 2004). The Environmental Science Division of Argonne National Laboratory implemented the investigation on behalf of the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA). The investigation was designed to (1) update the conceptual site model and (2) investigate sources of previously identified carbon tetrachloride contamination in groundwater. Six technical objectives were proposed in the ''Work Plan'' (Argonne 2005). The ''Work Plan'' was approved by the KDHE on March 28, 2005 (KDHE 2005). The six objectives were as follows: (1) Determine the current configuration of the carbon tetrachloride plume in the investigation area. (2) Delineate contamination detected in 1998-1999 at the former CCC/USDA facility. (3) Investigate the Pro-Ag Co-op property for evidence of releases of carbon tetrachloride. (4) Investigate the area adjacent to the site of the former retail store for evidence of releases of carbon tetrachloride to the subsurface. (5) Collect data to support the analysis of potential remedial alternatives. (6) Update the inventory of private wells to identify potential downgradient receptors. This report details and interprets the data collected during the 2005 investigation at Agra. The investigation met the objectives defined in the ''Work Plan''.

  16. In situ treatment of arsenic contaminated groundwater by aquifer iron coating: Experimental study.

    PubMed

    Xie, Xianjun; Wang, Yanxin; Pi, Kunfu; Liu, Chongxuan; Li, Junxia; Liu, Yaqing; Wang, Zhiqiang; Duan, Mengyu

    2015-09-15

    In situ arsenic removal from groundwater by an aquifer iron coating method has great potential to be a cost effective and simple groundwater remediation technology, especially in rural and remote areas where groundwater is used as the main water source for drinking. The in situ arsenic removal technology was first optimized by simulating arsenic removal in various quartz sand columns under anoxic conditions. The effectiveness was then evaluated in an actual high-arsenic groundwater environment. The arsenic removal mechanism by the coated iron oxide/hydroxide was investigated under different conditions using scanning electron microscopy (SEM)/X-ray absorption spectroscopy, electron probe microanalysis, and Fourier transformation infrared spectroscopy. Aquifer iron coating method was developed via a 4-step alternating injection of oxidant, iron salt and oxygen-free water. A continuous injection of 5.0mmol/L FeSO4 and 2.5mmol/L NaClO for 96h can form a uniform goethite coating on the surface of quartz sand without causing clogging. At a flow rate of 7.2mL/min of the injection reagents, arsenic (as Na2HAsO4) and tracer fluorescein sodium to pass through the iron-coated quartz sand column were approximately at 126 and 7 column pore volumes, respectively. The retardation factor of arsenic was 23.0, and the adsorption capacity was 0.11mol As per mol Fe. In situ arsenic removal from groundwater in an aquifer was achieved by simultaneous injections of As(V) and Fe(II) reagents. Arsenic fixation resulted from a process of adsorption/co-precipitation with fine goethite particles by way of bidentate binuclear complexes. Therefore, the study results indicate that the high arsenic removal efficiency of the in situ aquifer iron coating technology likely resulted from the expanded specific surface area of the small goethite particles, which enhanced arsenic sorption capability and/or from co-precipitation of arsenic on the surface of goethite particles. PMID:25956146

  17. Remediation of the Highland Drive South Ravine, Port Hope, Ontario: Contaminated Groundwater Discharge Management Using Permeable Reactive Barriers and Contaminated Sediment Removal - 13447

    SciTech Connect

    Smyth, David; Roos, Gillian [Golder Associates Ltd., 2390 Argentia Road, Mississauga, ON L5N 5Z7 (Canada)] [Golder Associates Ltd., 2390 Argentia Road, Mississauga, ON L5N 5Z7 (Canada); Ferguson Jones, Andrea [MMM Group Ltd., 100 Commerce Valley Drive West, Thornhill, ON L3T 0A1 (Canada)] [MMM Group Ltd., 100 Commerce Valley Drive West, Thornhill, ON L3T 0A1 (Canada); Case, Glenn [AECL Port Hope Area Initiative Management Office, 115 Toronto Road, Port Hope, ON L1A 3S4 (Canada)] [AECL Port Hope Area Initiative Management Office, 115 Toronto Road, Port Hope, ON L1A 3S4 (Canada); Yule, Adam [Public Works and Government Services Canada, 4900 Yonge Street, 11th Floor, Toronto, ON, M2N 6A6 (Canada)] [Public Works and Government Services Canada, 4900 Yonge Street, 11th Floor, Toronto, ON, M2N 6A6 (Canada)

    2013-07-01

    The Highland Drive South Ravine (HDSR) is the discharge area for groundwater originating from the Highland Drive Landfill, the Pine Street North Extension (PSNE) roadbed parts of the Highland Drive roadbed and the PSNE Consolidation Site that contain historical low-level radioactive waste (LLRW). The contaminant plume from these LLRW sites contains elevated concentrations of uranium and arsenic and discharges with groundwater to shallow soils in a wet discharge area within the ravine, and directly to Hunt's Pond and Highland Drive South Creek, which are immediately to the south of the wet discharge area. Remediation and environmental management plans for HDSR have been developed within the framework of the Port Hope Project and the Port Hope Area Initiative. The LLRW sites will be fully remediated by excavation and relocation to a new Long-Term Waste Management Facility (LTWMF) as part of the Port Hope Project. It is projected, however, that the groundwater contaminant plume between the remediated LLRW sites and HDSR will persist for several hundreds of years. At the HDSR, sediment remediation within Hunt's Ponds and Highland Drive South Creek, excavation of the existing and placement of clean fill will be undertaken to remove current accumulations of solid-phase uranium and arsenic associated with the upper 0.75 m of soil in the wet discharge area, and permeable reactive barriers (PRBs) will be used for in situ treatment of contaminated groundwater to prevent the ongoing discharge of uranium and arsenic to the area in HDSR where shallow soil excavation and replacement has been undertaken. Bench-scale testing using groundwater from HDSR has confirmed excellent treatment characteristics for both uranium and arsenic using permeable reactive mixtures containing granular zero-valent iron (ZVI). A sequence of three PRBs containing ZVI and sand in backfilled trenches has been designed to intercept the groundwater flow system prior to its discharge to the ground surface and the creek and ponds in the HDSR. The first of the PRBs will be installed immediately up-gradient of the wet discharge area approximately 50 m from the creek, the other two will be installed across the area of shallow soil replacement, and all will extend from ground surface to the base of the water table aquifer through which the impacted groundwater flows. The PRBs have been designed to provide the removal of uranium and arsenic for decades, although the capacity of the treatment mixture for contaminant removal suggests that a longer period of treatment may be feasible. The environmental management plan includes an allowance for on-going monitoring, and replacement of a PRB(s) as might be required. (authors)

  18. Stimulating the In Situ Activity of Geobacter Species To Remove Uranium from the Groundwater of a Uranium-Contaminated Aquifer

    PubMed Central

    Anderson, Robert T.; Vrionis, Helen A.; Ortiz-Bernad, Irene; Resch, Charles T.; Long, Philip E.; Dayvault, Richard; Karp, Ken; Marutzky, Sam; Metzler, Donald R.; Peacock, Aaron; White, David C.; Lowe, Mary; Lovley, Derek R.

    2003-01-01

    The potential for removing uranium from contaminated groundwater by stimulating the in situ activity of dissimilatory metal-reducing microorganisms was evaluated in a uranium-contaminated aquifer located in Rifle, Colo. Acetate (1 to 3 mM) was injected into the subsurface over a 3-month period via an injection gallery composed of 20 injection wells, which was installed upgradient from a series of 15 monitoring wells. U(VI) concentrations decreased in as little as 9 days after acetate injection was initiated, and within 50 days uranium had declined below the prescribed treatment level of 0.18 ?M in some of the monitoring wells. Analysis of 16S ribosomal DNA (rDNA) sequences and phospholipid fatty acid profiles demonstrated that the initial loss of uranium from the groundwater was associated with an enrichment of Geobacter species in the treatment zone. Fe(II) in the groundwater also increased during this period, suggesting that U(VI) reduction was coincident with Fe(III) reduction. As the acetate injection continued over 50 days there was a loss of sulfate from the groundwater and an accumulation of sulfide and the composition of the microbial community changed. Organisms with 16S rDNA sequences most closely related to those of sulfate reducers became predominant, and Geobacter species became a minor component of the community. This apparent switch from Fe(III) reduction to sulfate reduction as the terminal electron accepting process for the oxidation of the injected acetate was associated with an increase in uranium concentration in the groundwater. These results demonstrate that in situ bioremediation of uranium-contaminated groundwater is feasible but suggest that the strategy should be optimized to better maintain long-term activity of Geobacter species. PMID:14532040

  19. Two- and Three-Dimensional Depiction of Subsurface Geology Using Commercial Software for Support of Groundwater Contaminant Fate and Transport Analysis - 13345

    SciTech Connect

    Ivarson, Kristine A. [North Wind, Inc. Richland, Washington 99352 (United States)] [North Wind, Inc. Richland, Washington 99352 (United States); Miller, Charles W.; Arola, Craig C. [CH2M HILL Plateau Remediation Company, Richland, Washington 99352 (United States)] [CH2M HILL Plateau Remediation Company, Richland, Washington 99352 (United States)

    2013-07-01

    Groundwater contamination by hexavalent chromium and other nuclear reactor operation-related contaminants has resulted in the need for groundwater remedial actions within the Hanford Site reactor areas (the Hanford Site 100 Area). The large geographic extent of the resultant contaminant plumes requires an extensive level of understanding of the aquifer structure, characteristics, and configuration to support assessment and design of remedial alternatives within the former 100-D, 100-H, and 100-K reactor areas. The authors have prepared two- and three-dimensional depictions of the key subsurface geologic structures at two Hanford Site reactor operable units (100-K and 100-D/H). These depictions, prepared using commercial-off-the-shelf (COTS) visualization software, provide a basis for expanding the understanding of groundwater contaminant migration pathways, including identification of geologically-defined preferential groundwater flow pathways. These identified preferential flow pathways support the conceptual site model and help explain both historical and current contaminant distribution and transport. (authors)

  20. Economical Analysis of a Groundwater Source Heat Pump with Water Thermal Storage System 

    E-print Network

    Zhou, Z.; Xu, W.; Li, J.; Zhao, J.; Niu, L.

    2006-01-01

    The paper is based on a chilled and heat source for the building which has a total area of 140000m2 in the suburb of Beijing. By comparing the groundwater source heat pump of water thermal storage (GHPWTS) with a conventional chilled and heat source...

  1. Sources of nitrate contamination and age of water in large karstic springs of Florida

    USGS Publications Warehouse

    Katz, B.G.

    2004-01-01

    In response to concerns about the steady increase in nitrate concentrations over the past several decades in many of Florida's first magnitude spring waters (discharge ???2.8 m3/s), multiple isotopic and other chemical tracers were analyzed in water samples from 12 large springs to assess sources and timescales of nitrate contamination. Nitrate-N concentrations in spring waters ranged from 0.50 to 4.2 mg/L, and ??15N values of nitrate in spring waters ranged from 2.6 to 7.9 per mil. Most ??15N values were below 6 per mil indicating that inorganic fertilizers were the dominant source of nitrogen in these waters. Apparent ages of groundwater discharging from springs ranged from 5 to about 35 years, based on multi-tracer analyses (CFC-12, CFC-113, SF6, 3H/3He) and a piston flow assumption; however, apparent tracer ages generally were not concordant. The most reliable spring-water ages appear to be based on tritium and 3He data, because concentrations of CFCs and SF6 in several spring waters were much higher than would be expected from equilibration with modern atmospheric concentrations. Data for all tracers were most consistent with output curves for exponential and binary mixing models that represent mixtures of water in the Upper Floridan aquifer recharged since the early 1960s. Given that groundwater transit times are on the order of decades and are related to the prolonged input of nitrogen from multiple sources to the aquifer, nitrate could persist in groundwater that flows toward springs for several decades due to slow transport of solutes through the aquifer matrix.

  2. Identifying Methane Sources in Groundwater; Quantifying Changes in Compositional and Stable Isotope Values during Multiphase Transport

    NASA Astrophysics Data System (ADS)

    Larson, T.; Sathaye, K.

    2014-12-01

    A dramatic expansion of hydraulic fracturing and horizontal drilling for natural gas in unconventional reserves is underway. This expansion is fueling considerable public concern, however, that extracted natural gas, reservoir brines and associated fracking fluids may infiltrate to and contaminate shallower (< 500m depth) groundwater reservoirs, thereby posing a health threat. Attributing methane found in shallow groundwater to either deep thermogenic 'fracking' operations or locally-derived shallow microbial sources utilizes geochemical methods including alkane wetness and stable carbon and hydrogen isotope ratios of short chain (C1-C5) hydrocarbons. Compared to shallow microbial gas, thermogenic gas is wetter and falls within a different range of ?13C and ?D values. What is not clear, however, is how the transport of natural gas through water saturated geological media may affect its compositional and stable isotope values. What is needed is a means to differentiate potential flow paths of natural gas including 'fast paths' along preexisting fractures and drill casings vs. 'slow paths' through low permeability rocks. In this study we attempt quantify transport-related effects using experimental 1-dimensional two-phase column experiments and analytical solutions to multi-phase gas injection equations. Two-phase experimental results for an injection of natural gas into a water saturated column packed with crushed illite show that the natural gas becomes enriched in methane compared to ethane and propane during transport. Carbon isotope measurements are ongoing. Results from the multi-phase gas injection equations that include methane isotopologue solubility and diffusion effects predict the development of a 'bank' of methane depleted in 13C relative to 12C at the front of a plume of fugitive natural gas. These results, therefore, suggest that transport of natural gas through water saturated geological media may complicate attribution methods needed to distinguish thermogenic and microbial methane.

  3. Modeling the impact of the nitrate contamination on groundwater at the groundwater body scale : The Geer basin case study (Invited)

    NASA Astrophysics Data System (ADS)

    Brouyere, S.; Orban, P.; Hérivaux, C.

    2009-12-01

    In the next decades, groundwater managers will have to face regional degradation of the quantity and quality of groundwater under pressure of land-use and socio-economic changes. In this context, the objectives of the European Water Framework Directive require that groundwater be managed at the scale of the groundwater body, taking into account not only all components of the water cycle but also the socio-economic impact of these changes. One of the main challenges remains to develop robust and efficient numerical modeling applications at such a scale and to couple them with economic models, as a support for decision support in groundwater management. An integrated approach between hydrogeologists and economists has been developed by coupling the hydrogeological model SUFT3D and a cost-benefit economic analysis to study the impact of agricultural practices on groundwater quality and to design cost-effective mitigation measures to decrease nitrate pressure on groundwater so as to ensure the highest benefit to the society. A new modeling technique, the ‘Hybrid Finite Element Mixing Cell’ approach has been developed for large scale modeling purposes. The principle of this method is to fully couple different mathematical and numerical approaches to solve groundwater flow and solute transport problems. The mathematical and numerical approaches proposed allows an adaptation to the level of local hydrogeological knowledge and the amount of available data. In combination with long time series of nitrate concentrations and tritium data, the regional scale modelling approach has been used to develop a 3D spatially distributed groundwater flow and solute transport model for the Geer basin (Belgium) of about 480 km2. The model is able to reproduce the spatial patterns of nitrate concentrations together nitrate trends with time. The model has then been used to predict the future evolution of nitrate trends for two types of scenarios: (i) a “business as usual scenario” where current polluting pressures remain the same and (ii) two contrasted scenarios that simulate the implementation of programs of measures aiming at reaching good chemical status. The results of the hydrogeological model under the “business as usual scenario” have been used to assess the cost for the society of the continuous degradation of the groundwater quality. The results of the hydrogeological model under the two contrasted scenarios have been used to assess the economical benefit as avoided damage resulting from the decrease in the nitrate load. A cost-benefit analysis has been thus performed to assess the programme of mitigation measures which provides the largest benefits at the lowest cost.

  4. Hydrological and sedimentary controls leading to arsenic contamination of groundwater in the Hanoi area, Vietnam: The impact of iron-arsenic ratios, peat, river bank deposits, and excessive groundwater abstraction

    Microsoft Academic Search

    Michael Berg; Pham Thi Kim Trang; Caroline Stengel; Johanna Buschmann; Pham Hung Viet; Nguyen Van Dan; Walter Giger; Doris Stüben

    2008-01-01

    Groundwater contamination by arsenic in Vietnam poses a serious health threat to millions of people. In the larger Hanoi area, elevated arsenic levels are present in both, the Holocene and Pleistocene aquifers. Family-based tubewells predominantly tap the Holocene aquifer, while the Hanoi water works extract more than 600,000 m3\\/day of groundwater from the Pleistocene aquifer. Detailed groundwater and sediment investigations were

  5. Assessment of groundwater quality and contamination problems ascribed to an abandoned uranium mine (Cunha Baixa region, Central Portugal)

    Microsoft Academic Search

    O. Neves; M. J. Matias

    2008-01-01

    The assessment of groundwater quality and its environmental implications in the region of the abandoned Cunha Baixa uranium\\u000a mine (Central Portugal) was carried out from 1995 to 2004. Shallow groundwater is the major water supply source for irrigation\\u000a in the neighbourhood of Cunha Baixa village. Water samples from the mine site as well as from private wells were collected\\u000a in

  6. Estimating the effectiveness of health-risk communications with propensity-score matching: application to arsenic groundwater contamination in four US locations.

    PubMed

    Leidner, Andrew J

    2014-01-01

    This paper provides a demonstration of propensity-score matching estimation methods to evaluate the effectiveness of health-risk communication efforts. This study develops a two-stage regression model to investigate household and respondent characteristics as they contribute to aversion behavior to reduce exposure to arsenic-contaminated groundwater. The aversion activity under study is a household-level point-of-use filtration device. Since the acquisition of arsenic contamination information and the engagement in an aversion activity may be codetermined, a two-stage propensity-score model is developed. In the first stage, the propensity for households to acquire arsenic contamination information is estimated. Then, the propensity scores are used to weight observations in a probit regression on the decision to avert the arsenic-related health risk. Of four potential sources of information, utility, media, friend, or others, information received from a friend appears to be the source of information most associated with aversion behavior. Other statistically significant covariates in the household's decision to avert contamination include reported household income, the presence of children in household, and region-level indicator variables. These findings are primarily illustrative and demonstrate the usefulness of propensity-score methods to estimate health-risk communication effectiveness. They may also be suggestive of areas for future research. PMID:25349622

  7. Estimating the Effectiveness of Health-Risk Communications with Propensity-Score Matching: Application to Arsenic Groundwater Contamination in Four US Locations

    PubMed Central

    Leidner, Andrew J.

    2014-01-01

    This paper provides a demonstration of propensity-score matching estimation methods to evaluate the effectiveness of health-risk communication efforts. This study develops a two-stage regression model to investigate household and respondent characteristics as they contribute to aversion behavior to reduce exposure to arsenic-contaminated groundwater. The aversion activity under study is a household-level point-of-use filtration device. Since the acquisition of arsenic contamination information and the engagement in an aversion activity may be codetermined, a two-stage propensity-score model is developed. In the first stage, the propensity for households to acquire arsenic contamination information is estimated. Then, the propensity scores are used to weight observations in a probit regression on the decision to avert the arsenic-related health risk. Of four potential sources of information, utility, media, friend, or others, information received from a friend appears to be the source of information most associated with aversion behavior. Other statistically significant covariates in the household's decision to avert contamination include reported household income, the presence of children in household, and region-level indicator variables. These findings are primarily illustrative and demonstrate the usefulness of propensity-score methods to estimate health-risk communication effectiveness. They may also be suggestive of areas for future research. PMID:25349622

  8. Pyrosequence Analysis of Unamplified and Whole Genome Amplified DNA from Hydrocarbon-Contaminated Groundwater

    Microsoft Academic Search

    Nathlee S. Abbai; Algasan Govender; Rehana Shaik; Balakrishna Pillay

    Pyrosequence data was used to analyze the composition and metabolic potential of a metagenome from a hydrocarbon-contaminated\\u000a site. Unamplified and whole genome amplified (WGA) sequence data was compared from this source. According to MG-RAST, an additional\\u000a 2,742,252 bp of DNA was obtained with the WGA, indicating that WGA has the ability to generate a large amount of DNA from\\u000a a

  9. Epidemiological investigations into the sources of Salmonella contamination of pork.

    PubMed

    Swanenburg, M; Berends, B R; Urlings, H A; Snijders, J M; van Knapen, F

    2001-01-01

    This study was conducted to elucidate which phases of the pork production chain contribute to the Salmonella contamination on pork after slaughter. During 7 sampling days, samples were collected of randomly selected slaughter pigs and of pigs from selected Salmonella-infected and Salmonella-free herds, trucks, lairages, and slaughterlines, in two slaughterhouses. Salmonella genotypes, present on pork after slaughter, were compared with Salmonella types, present on the farm, in the truck, in the lairage, on slaughter equipment, and in pigs from other herds. Results showed that the slaughterline was the most important source of Salmonella contamination of carcasses. The farm was the most important source of contamination of livers, tongues, rectal samples and mesenterial lymphnodes, for pigs originating from sero-positive herds. The lairage was the most important contamination source for pigs originating from sero-negative herds, for all samples, except carcasses. It is recommended to avoid each direct or indirect contact between different herds along the whole pork production chain, especially between Salmonella-infected and Salmonella-free herds. PMID:11570177

  10. Optimal groundwater remediation design: Methodologies and software for contaminated aquifers. Final report

    SciTech Connect

    Dougherty, D.E. [Univ. of Vermont, Burlington, VT (United States). Research Center for Groundwater Remediation Design

    1994-10-31

    This document comprises the final report of work performed under sub-contract B-239648 between the Lawrence Livermore National Laboratory (LLNL) and the University of Vermont (UVM). This contract was subsidiary to one between LLNL and the U.S. Department of Energy (DOE). This project had the goal of developing tools and strategies regarding how and where and when to apply the environmental restoration (ER) technologies that are under development. The development of decision support software for advanced environmental remediation technologies is tentative; many of the ER technologies are poorly understood, the applicability of methods to new untested sites is questionable, the ability to predict the effects of alternative remediation designs is very limited, and there are a large number of uncertainties associated with processes and parameters (physical, chemical, and biological), contaminants (distribution and type), and sociopolitical environment. Nevertheless, the potential for significant savings by using optimal design methods and the need to make decisions regardless of uncertainties has made this project worthy. A stop-work order was received in September 1994. An additional upper limit of $15,000 was provided for project termination activities, including report preparation. One of four deliverables was completed and provided to LLNL. MODLP is a computational tool for use in groundwater remediation design. It is a FORTRAN program that incorporates the well known and widely used MODFLOW simulator to represent flow of water in a saturated natural porous medium. MODLP is designed to allow the user to create and solve optimization problems for hydraulic control in groundwater systems. Inasmuch as environmental restoration costs are very large, savings of on the order of ten percent represent significant amounts, and optimal design has been demonstrated to help produce savings larger than ten percent, these activities have an important role to play within DOE.

  11. Investigation of groundwater flow zones and contaminant transport in Solid Waste Storage Area 5 at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Environmental Restoration Program

    SciTech Connect

    Hicks, D.S.; Solomon, D.K.; Farrow, N.D.

    1992-09-01

    An understanding of subsurface transport processes is essential to produce realistic predictions of future contaminant discharge from Solid Waste Storage Areas (SWSAs) at Oak Ridge National Laboratory (ORNL). Locating groundwater flow zones (permeable pathways) and determining the relative contributions of primary vs secondary contaminant sources are critical to the proper selection and evaluation of remedial actions. Because groundwater discharge from SWSA 5 contributes significant amounts of {sup 3}H and {sup 90}Sr to the White Oak Creek watershed, an area on the southeastern edge of SWSA 5 was chosen for an investigation aimed at understanding and characterizing the subsurface movement of contaminants. Preliminary data collected in 1991 indicated that the vertical distribution of {sup 3}H (0.02 to 279 {mu}Ci/L) observed over the sampled interval (O to 10 ft deep) may be a result of upward diffusion from a hydraulically dominant fracture (or fractured zone) below the sampled interval. The investigation continued this year (1992) with the primary objective of defining where the most permeable zones exist in the subsurface and how they relate to the vertical extent of {sup 3}H. An open borehole was drilled on the southeastern edge of SWSA 5 through the upper zones of soil and saprolite and then through interbedded shales and limestones to a depth of about 26 ft. Two methods were used to determine permeable zones within the borehole. In addition, samples were collected monthly from a nearby well and seep (where tritiated groundwater discharges) to determine seasonal variability in the transport of {sup 3}H and {sup 90}Sr from the study area.

  12. Factors associated with sources, transport, and fate of chloroform and three other trihalomethanes in untreated groundwater used for drinking water

    USGS Publications Warehouse

    Carter, Janet M.; Moran, Michael J.; Zogorski, John S.; Price, Curtis V.

    2012-01-01

    Multiple lines of evidence for indicating factors associated with the sources, transport, and fate of chloroform and three other trihalomethanes (THMs) in untreated groundwater were revealed by evaluating low-level analytical results and logistic regression results for THMs. Samples of untreated groundwater from wells used for drinking water were collected from 1996-2007 from 2492 wells across the United States and analyzed for chloroform, bromodichloromethane, dibromochloromethane, and bromoform by a low-level analytical method implemented in April 1996. Using an assessment level of 0.02 ?g/L, chloroform was detected in 36.5% of public-well samples and 17.6% of domestic-well samples, with most concentrations less than 1 ?g/L. Brominated THMs occurred less frequently than chloroform but more frequently in public-well samples than domestic-well samples. For both public and domestic wells, THMs occurred most frequently in urban areas. Logistic regression analyses showed that the occurrence of THMs was related to nonpoint sources such as urban land use and to point sources like septic systems. The frequent occurrence and concentration distribution pattern of THMs, as well as their frequent co-occurrence with other organic compounds and nitrate, all known to have anthropogenic sources, and the positive associations between THM occurrence and dissolved oxygen and recharge indicate the recycling of water that contains THMs and other anthropogenic contaminants.

  13. Stable isotope fractionation related to microbial nitrogen turnover in constructed wetlands treating contaminated groundwater

    NASA Astrophysics Data System (ADS)

    Voloshchenko, O.; Knoeller, K.

    2013-12-01

    To improve the efficiency of ground- and wastewater treatment in constructed wetlands (CWs), better understanding of the occurring processes is necessary. This research explores N-isotope fractionations associated with the removal of ammonium from contaminated groundwater in pilot-scale CWs downstream of the chemical industrial area Leuna, Germany. The groundwater at the site is contaminated mainly by organic (BTEX, MTBE) and inorganic compounds (ammonium). We assume that the anaerobic ammonium oxidation (ANAMMOX) plays an important role in nitrogen removal in these CWs. However, to date, interactions between processes of aerobic and anaerobic ammonium oxidation in CWs still have not been well explored. Especially, the importance of the ANAMMOX process for the nitrogen removal is generally accepted, but its role in CWs is quite unknown. For this aim, three CWs were chosen: planted horizontal subsurface flow (HSSF); unplanted HSSF, and floating plant root mat (FPRM). Water samples were taken at the inflow and outflow as well as from the pore space at different distances (1, 2.5 and 4 m) from the inlet and at different depths (20, 30 and 40 cm in the HSSF-CWs, 30 cm in the FPRM). Samples were collected in a time interval of 1 to 6 weeks during 1 year with the exception of the winter season. Physicochemical parameters, nitrogen isotope signatures of ammonium, as well as nitrogen and oxygen isotope signatures of nitrate were analysed. Within the CWs, spatial concentration gradients of the nitrogen species (ammonium and nitrate) are observed. N-isotope variations of ammonium and nitrate are interpreted according to the prevailing processes of the N-transformations. Based on isotope mass-balance approach microbial processes such as nitrification, denitrification, and ANAMMOX are quantified. DNA from biofilms at roots and gravel was extracted using FastDNA Spin Kit For Soil (MP Biomedicals). PCR, quantitative PCR, cloning, and sequencing were applied with the purpose of getting information about the abundance and the community of key players of the N-cycle. Pyrosequencing and specific FISH probes in connection with confocal laser scanning microscopy will give information about structure and spatial distribution of the microbial nitrogen transforming community.

  14. Health burden of skin lesions at low arsenic exposure through groundwater in Pakistan. Is river the source?

    SciTech Connect

    Fatmi, Zafar, E-mail: zafar.fatmi@aku.edu [Department of Community Health Sciences, Aga Khan University, Stadium Road, P.O. Box 3500, Karachi (Pakistan)] [Department of Community Health Sciences, Aga Khan University, Stadium Road, P.O. Box 3500, Karachi (Pakistan); Azam, Iqbal; Ahmed, Faiza; Kazi, Ambreen; Gill, Albert Bruce; Kadir, Muhmmad Masood; Ahmed, Mubashir; Ara, Naseem; Janjua, Naveed Zafar [Department of Community Health Sciences, Aga Khan University, Stadium Road, P.O. Box 3500, Karachi (Pakistan)] [Department of Community Health Sciences, Aga Khan University, Stadium Road, P.O. Box 3500, Karachi (Pakistan)

    2009-07-15

    A significant proportion of groundwater in south Asia is contaminated with arsenic. Pakistan has low levels of arsenic in groundwater compared with China, Bangladesh and India. A representative multi-stage cluster survey conducted among 3874 persons {>=}15 years of age to determine the prevalence of arsenic skin lesions, its relation with arsenic levels and cumulative arsenic dose in drinking water in a rural district (population: 1.82 million) in Pakistan. Spot-urine arsenic levels were compared among individuals with and without arsenic skin lesions. In addition, the relation of age, body mass index, smoking status with arsenic skin lesions was determined. The geographical distribution of the skin lesions and arsenic-contaminated wells in the district were ascertained using global positioning system. The total arsenic, inorganic and organic forms, in water and spot-urine samples were determined by atomic absorption spectrophotometry. The prevalence of skin lesions of arsenic was estimated for complex survey design, using surveyfreq and surveylogistic options of SAS 9.1 software.The prevalence of definitive cases i.e. hyperkeratosis of both palms and soles, was 3.4 per 1000 and suspected cases i.e. any sign of arsenic skin lesions (melanosis and/or keratosis), were 13.0 per 1000 among {>=}15-year-old persons in the district. Cumulative arsenic exposure (dose) was calculated from levels of arsenic in water and duration of use of current drinking water source. Prevalence of skin lesions increases with cumulative arsenic exposure (dose) in drinking water and arsenic levels in urine. Skin lesions were 2.5-fold among individuals with BMI <18.5 kg/m{sup 2}. Geographically, more arsenic-contaminated wells and skin lesions were alongside Indus River, suggests a strong link between arsenic contamination of groundwater with proximity to river.This is the first reported epidemiological and clinical evidence of arsenic skin lesions due to groundwater in Pakistan. Further investigations and focal mitigation measures for arsenic may be carried out alongside Indus River.

  15. Arbuscular mycorrhizal fungi in a wetland constructed for benzene-, methyl tert-butyl ether- and ammonia-contaminated groundwater bioremediation.

    PubMed

    Fester, Thomas

    2013-01-01

    Arbuscular mycorrhizal fungi (AMF), which are present in most natural environments, have demonstrated capacity to promote biodegradation of organic pollutants in the greenhouse. However, it is not certain whether AMF can spontaneously establish in phytoremediation systems constructed to decontaminate groundwater, because of the unusual conditions during the construction and operation of such systems. To assess this possibility, root samples from a wetland constructed for th