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Sample records for tce perchloroethylene pce

  1. Insights into dechlorination of PCE and TCE from carbon isotope fractionation by vitamin B12

    NASA Astrophysics Data System (ADS)

    Slater, G.; Sherwood Lollar, B.; Lesage, S.; Brown, S.

    2003-04-01

    Reductive dechlorination of perchloroethylene (PCE) and trichloroethylene (TCE) by vitamin B12 is both a potential remediation technique and an analogue of the microbial reductive dechlorination reaction. Stable carbon isotopic analysis, an effective and powerful tool for the investigation and monitoring of contaminant remediation, was used to characterize the isotopic effects of reductive dechlorination of PCE and TCE by vitamin B12 in laboratory microcosms. 10 mg/L vitamin B12 degraded greater than 90% of an initial concentration of PCE of 20 mg/L. TCE, the primary product of PCE degradation, accounted for between 64 - 72% of the PCE degraded. In experiments with TCE, 147 mg/L vitamin B12 degraded greater than 90% of an initial concentration of TCE of 20 mg/L. Cis-dichloroethene (cDCE), the primary product of TCE degradation, accounted for between 30 - 35% of the TCE degraded. Degradation of both PCE and TCE exhibited first order kinetics. Strong isotopic fractionation of the reactant PCE and of the reactant TCE was observed over the course of degradation. This fractionation could be described by a Rayleigh model with enrichment factors between -16.5 ppm and -15.8 ppm for PCE, and -17.2 ppm and -16.6 ppm for TCE. Fractionation was similar in all four experiments, with a mean enrichment factor of -16.5 +/- 0.6 ppm. These large enrichment factors indicate that isotopic analysis can be used to assess the occurrence of dechlorination of PCE and TCE by vitamin B12 in remediation situations. Significantly, the Rayleigh model could be used to predict the isotopic compositions of the major products of the reaction as well as the reactant, notwithstanding the lack of complete mass balance observed between product and reactant. This evidence suggests that isotopic fractionation is taking place during complexation of the chlorinated ethenes to vitamin B12, as has been suggested for reductive dechlorination by zero valent iron. The differences between e for this reaction and those observed for microbial biodegradation of the chlorinated ethenes suggest that there may be differences in the rate determining step for these two processes. Determining which steps are rate determining during degradation may allow optimization of contaminant remediation.

  2. PCE/TCE DEGRADATION USING MULCH BIOWALLS

    EPA Science Inventory

    A passive reactive barrier (Biowall) was installed at the OU-1 site at Altus Air Force Base, Oklahoma to treat TCE contamination in ground water from a landfill. Depth to ground water varies from 1.8 to 2.4 meters below land surface. To intercept and treat the plume of contamin...

  3. REPORT ON THE GEOELECTRICAL DETECTION OF SURFACTANT ENHANCED AQUIFER REMEDIATION OF PCE: PROPERTY CHANGES IN AQUEOUS SOLUTIONS DUE TO SURFACTANT TREATMENT OF PERCHLOROETHYLENE: IMPLICATIONS TO GEOPHYSICAL MEASUREMENTS

    EPA Science Inventory

    Select physicochemical properties of nine surfactants which are conventionally used in the remediation of perchloroethylene (PCE, a.k.a. tetrachloroethene) were evaluated with varying concentrations of PCE and indicator dyes in aqueous solutions using a response surface quadrati...

  4. Dechlorination of PCE and TCE to ethene using an anaerobic microbial consortium

    SciTech Connect

    Wu, W.M.; Nye, J.; Jain, M.K.; Zeikus, J.G.; Hickey, R.F.

    1995-12-31

    An anaerobic microbial consortium capable of dechlorinating chlorinated ethenes to ethylene has been developed as anaerobic granules in a laboratory-scale upflow anaerobic reactor (34 L) under ambient temperature conditions. Dechlorination of tetrachloroethene (PCE), trichloroethene (TCE), and dichloroethenes (DCEs) to ethene occurred under a wide temperature range tested. TCE, cis-1,2-DCE, and vinyl chloride (VC) are sequential intermediates of PCE dechlorination. The consortium also dechlorinated trans-1,2-DCE and 1,1-DCE to ethene. Various substrates for methane production can support dechlorination by this consortium. The feasibility of application of the microbial consortium as a microbial inoculum for treatment of groundwater and saturated soils were examined in bench-scale systems. Preliminary results indicate that the consortium can effectively dechlorinate PCE and TCE to ethene in saturated soils.

  5. COMPLETE NATURAL ATTENUATION OF A PCE AND TCE PLUME AFTER SOURCE REMOVAL

    EPA Science Inventory

    Disposal of the chlorinated solvents PCE and TCE at the Twin Cities Army Ammunition Plant (TCAAP) resulted in the contamination of groundwater in a shallow, unconsolidated sand aquifer. The resulting plume had moved over 1000 feet from the disposal source area and had impacted p...

  6. Effects of alcohols, anionic and nonionic surfactants on the reduction of PCE and TCE by zero-valent iron.

    PubMed

    Loraine, G A

    2001-04-01

    The effects of surfactants, sodium dodecyl sulfate (SDS) and Triton X-a00 (TX), and alcohols (methanol, ethanol, and propanol) on the dehalogenation of TCE and PCE by zero-valent iron were examined. Surface concentrations of PCE and TCE on the iron were dependent on aqueous surfactant concentrations. At concentrations above the CMC, sorbed halocarbon concentrations declined and concentrations associated with solution phase micelles increased. The anionic surfactant SDS ([SDS] < CMC) did not affect reduction rates, until the CMC was exceeded after which reactivity decreased, possibly due to sequestering of the TCE and PCE in mobile micelles. The nonionic TX showed a mixed effect on reactivity, increasing the PCE reduction rate, but not affecting TCE removal. Production of TCE from PCE increased in the presence of TX. Similar experiments showed that methanol, ethanol, and propanol inhibited reduction of TCE and PCE by metallic iron. Zero-valent iron may be useful in recycling soil washing effluents contaminated with TCE and PCE. PMID:11317892

  7. Transformation efficiency and formation of transformation products during photochemical degradation of TCE and PCE at micromolar concentrations

    PubMed Central

    2014-01-01

    Background Trichloroethene and tetrachloroethene are the most common pollutants in groundwater and two of the priority pollutants listed by the U.S. Environmental Protection Agency. In previous studies on TCE and PCE photolysis and photochemical degradation, concentration ranges exceeding environmental levels by far with millimolar concentrations of TCE and PCE have been used, and it is not clear if the obtained results can be used to explain the degradation of these contaminants at more realistic environmental concentration levels. Methods Experiments with micromolar concentrations of TCE and PCE in aqueous solution using direct photolysis and UV/H2O2 have been conducted and product formation as well as transformation efficiency have been investigated. SPME/GC/MS, HPLC/UV and ion chromatography with conductivity detection have been used to determine intermediates of degradation. Results The results showed that chloride was a major end product in both TCE and PCE photodegradation. Several intermediates such as formic acid, dichloroacetic acid, dichloroacetaldehyede, chloroform, formaldehyde and glyoxylic acid were formed during both, UV and UV/H2O2 treatment of TCE. However chloroacetaldehyde and chloroacetic acid were only detected during direct UV photolysis of TCE and oxalic acid was only formed during the UV/H2O2 process. For PCE photodegradation, formic acid, di- and trichloroacetic acids were detected in both UV and UV/H2O2 systems, but formaldehyde and glyoxylic acid were only detected during direct UV photolysis. Conclusions For water treatment UV/H2O2 seems to be favorable over direct UV photolysis because of its higher degradation efficiency and lower risk for the formation of harmful intermediates. PMID:24401763

  8. Sulfur removal from high-sulfur Illinois coal by low-temperature perchloroethylene (PCE) extraction. Final technical report, 1 September, 1992--31 August, 1993

    SciTech Connect

    Chou, M.I.M.; Lytle, J.M.; Ruch, R.R.; Kruse, C.W.; Chaven, C.; Hackley, K.C.; Hughes, R.E.; Harvey, R.D.; Frost, J.K.; Buchanan, D.H.; Stucki, J.W.; Huffman, G.P.; Huggins, F.E.

    1993-12-31

    The Midwest Ore Processing Co. (MWOPC) has reported a precombustion coal desulfurization process using perchloroethylene (PCE) at 120 C to remove up to 70% of the organic sulfur. The purposes of this research were to independently confirm and possibly to improve the organic sulfur removal from Illinois coals with the PCE desulfurization and to verify the ASTM forms-of-sulfur determination for evaluation of the process. An additional goal was to develop a dechlorination procedure to remove excess PCE from the PCE-treated coal. A laboratory scale operation of the MWOPC PCE desulfurization process was demonstrated, and a dechlorination procedure to remove excess PCE from the PCE-treated coal was developed. The authors have determined that PCE desulfurization removed mainly elemental sulfur from coal. The higher the level of coal oxidization, the larger the amount of elemental sulfur that is removed by PCE extraction. The increased elemental sulfur during short-term preoxidation is found to be pH dependent and is attributed to coal pyrite oxidation under acidic (pH < 2) conditions. The non-ASTM sulfur analyses confirmed the hypothesis that the elemental sulfur produced by oxidation of pyrite complicates the interpretation of analytical data for PCE process evaluations when only the ASTM forms-of-sulfur is used. When the ASTM method is used alone, the elemental sulfur removed during PCE desulfurization is counted as organic sulfur. A study using model compounds suggests that mild preoxidation treatment of coal described by MWOPC for removal of organic sulfur does not produce enough oxidized organic sulfur to account for the amounts of sulfur removal reported. Furthermore, when oxidation of coal-like organosulfur compounds does occur, the products are inconsistent with production of elemental sulfur, the product reported by MWOPC. Overall, it is demonstrated that the PCE process is not suitable for organic sulfur removal.

  9. Identification of TCE and PCE sorption and biodegradation parameters in a sandy aquifer for fate and transport modelling: batch and column studies.

    PubMed

    Kret, E; Kiecak, A; Malina, G; Nijenhuis, I; Postawa, A

    2015-07-01

    The main aim of this study was to determine the sorption and biodegradation parameters of trichloroethene (TCE) and tetrachloroethene (PCE) as input data required for their fate and transport modelling in a Quaternary sandy aquifer. Sorption was determined based on batch and column experiments, while biodegradation was investigated using the compound-specific isotope analysis (CSIA). The aquifer materials medium (soil 1) to fine (soil 2) sands and groundwater samples came from the representative profile of the contaminated site (south-east Poland). The sorption isotherms were approximately linear (TCE, soil 1, K d?=?0.0016; PCE, soil 1, K d?=?0.0051; PCE, soil 2, K d?=?0.0069) except for one case in which the best fitting was for the Langmuir isotherm (TCE, soil 2, K f?=?0.6493 and S max?=?0.0145). The results indicate low retardation coefficients (R) of TCE and PCE; however, somewhat lower values were obtained in batch compared to column experiments. In the column experiments with the presence of both contaminants, TCE influenced sorption of PCE, so that the R values for both compounds were almost two times higher. Non-significant differences in isotope compositions of TCE and PCE measured in the observation points (?(13)C values within the range of -23.6?÷?-24.3‰ and -26.3?÷-27.7‰, respectively) indicate that biodegradation apparently is not an important process contributing to the natural attenuation of these contaminants in the studied sandy aquifer. PMID:25647491

  10. PHOTOCHEMICAL REACTIVITY OF PERCHLOROETHYLENE

    EPA Science Inventory

    Perchloroethylene (PCE), a solvent used in dry cleaning, has been suspected of contributing significantly to photochemical ozone/oxidant (O3/Ox) problems in urban atmospheres. Past evidence, however, was neither complete nor consistent. To interpret more conclusively the past evi...

  11. Transition Metal Catalyst Assisted Reductive Dechlorination of Perchloroethylene by Anaerobic Aquifer Enrichments

    SciTech Connect

    Lee, Brady Douglas; Schaller, Kastli Dianne; Apel, William Arnold; Watwood, Maribeth E.

    2000-04-01

    Bioremediation of groundwater contaminated with chlorinated solvents, such as perchloroethylene (PCE) or carbon tetrachloride, can be accomplished by adding nutrients to stimulate a microbial community capable of reductive dechlorination. However, biotransformation of these solvents, especially PCE, typically occurs very slowly or not at all. Experiments were conducted to evaluate whether the addition of transition metal tetrapyrrole catalysts would increase the reductive transformation of PCE to trichloroethylene (TCE) by sulfate-reducing enrichment cultures. Batch assays were used to test vitamin B12 and two synthetic sulfonatophenyl porphine catalysts for the stimulation of reductive dechlorination of PCE by sulfate-reducing bacteria (SRB) enriched from aquifer sediments from two locations at Dover Air Force Base. Cells from the enrichments were concentrated and added to batch assay vials. Vials containing SRB cells amended with vitamin B12 exhibited enhanced transformation of PCE to TCE compared with reactors amended with either synthetic catalysts or reactors containing cells alone. Methane production was observed in reactors that exhibited maximum levels of dechlorination. Storage of aquifer sediments between enrichments led to decreased levels of PCE dechlorination in subsequent assays.

  12. Effects of trichloroethylene and perchloroethylene on wild rodents at Edwards Air Force Base, California, USA

    USGS Publications Warehouse

    Spring, S.E.; Miles, A.K.; Anderson, M.J.

    2004-01-01

    Effects of inhalation of volatilized trichloroethylene (TCE) or perchloroethylene (PCE) were assessed based on the health and population size of wild, burrowing mammals at Edwards Air Force Base (CA, USA). Organic soil-vapor concentrations were measured at three sites with aquifer contamination of TCE or PCE of 5.5 to 77 mg/L and at two uncontaminated reference sites. Population estimates of kangaroo rats (Dipodomys merriami and D. panamintinus) as well as hematology, blood chemistry, and histopathology of kangaroo rats and deer mice (Peromyscus maniculatus) were compared between contaminated and uncontaminated populations. Maximum soil-gas concentrations associated with groundwater contamination were less than 1.5 ??l/L of TCE and 0.07 ??l/L of PCE. Population estimates of kangaroo rats were similar at contaminated and reference sites. Hematology, blood chemistry, and histopathology of kangaroo rats and deer mice indicated no evidence of health effects caused by exposure. Trichloroethylene or PCE in groundwater and in related soil gas did not appear to reduce the size of small mammal populations or impair the health of individuals.

  13. Enhanced Perchloroethylene Reduction Using Surfactant-Modified Zeolite/Zero-Valent Iron Pellets

    NASA Astrophysics Data System (ADS)

    Zhang, P.; Tao, X.; Bowman, R. S.

    2001-12-01

    We determined the effect of surfactant modification on perchloroethylene (PCE) reduction by zeolite/zero-valent iron (ZVI) pellets. We packed the pellets into four columns (30-cm long, 4.8-cm diameter) and modified two of the columns by sorbing the cationic surfactant hexadecyltrimethylammonium chloride (HDTMA-Cl) onto the pellets. We then continuously injected 11.0 ? M PCE into the columns and monitored the effluent concentrations of PCE, trichloroethylene (TCE), cis-, trans-, and 1,1-dichloroethylene (DCE), and vinyl chloride. The effluent PCE concentrations for the surfactant-modified columns were significantly lower than those for the unmodified columns (i.e., by factors of 6, 4, and 3 at pore water velocities of 0.5, 1.0, and 2.0 m/day, respectively). PCE reduction rate constants were three times higher for the modified columns relative to the unmodified columns at the three velocities. For a given column, the PCE reduction rate constant did not decrease as the pore water velocity increased from 0.5 m/day to 2.0 m/day. TCE was observed in the effluent of the modified and unmodified columns, with the concentrations for the modified columns (0.2, 0.4, and 0.7 ? M at 0.5, 1.0, and 2.0 m/day, respectively) roughly 10 times higher than those for the unmodified columns. No cis-DCE was detected in the effluent of the unmodified columns, whereas noticeable amounts (0.01-0.03 ? M) of cis-DCE were observed in the effluent of the modified columns. No trans-DCE, 1,1-DCE, or vinyl chloride was detected in the effluents of the modified or unmodified columns. Our results clearly demonstrate that the modification of zeolite/ZVI pellets with HDTMA significantly enhances PCE reduction. The enhanced PCE reduction may be due to an increased local PCE concentration in the vicinity of ZVI surface as a result of PCE sorption by the modified pellets. Our data also suggest that the PCE reduction mechanism for the modified pellets differs from that for the unmodified pellets, as seen by the much higher TCE and cis-DCE generation with the modified pellets.

  14. PHOTOCHEMICAL REACTIVITY OF PERCHLOROETHYLENE: A NEW APPRAISAL

    EPA Science Inventory

    Perchloroethylene (PCE), a solvent used in dry cleaning, has been suspected of contributing significantly to photochemical ozone/oxidant (O3/O(x)) problems in urban atmospheres. Past evidence, however, was neither complete nor consistent. To interpret more conclusively the past e...

  15. Chemical Reduction of PCE by Zero Valent Iron Colloids Batch and Column Experiments

    E-print Network

    Cirpka, Olaf Arie

    [-] PCE - Inflow PCE - Outflow TCE - Inflow TCE - Outflow Chloride - Outflow Blank Value Chloride pH Value 34 39 43 48 Pore-Volume [-] pH[-] PCE - Outflow TCE - Outflow Chloride - Outflow Blank Value Chloride pH Value nZVI-reinjection NAPASAN Particle - nZVI & Ca(OH)2 / PCE-DNAPL 0 20 40 60 80 100 120 140 0

  16. RESPONSE TO ISSUES AND DATA SUBMISSIONS ON THE CARCINOGENICITY OF TETRACHLOROETHYLENE (PERCHLOROETHYLENE)

    EPA Science Inventory

    The scientific debate over the potential carcinogenicity of tetrachloroethylene (perchloroethylene, perc, PCE) spans several years. his document reviews the issues considered by the EPA's Science Advisory Board (SAB) during its review of the Draft Addendum to the Health Assessmen...

  17. PHASE BEHAVIOR OF WATER/PERCHLOROETHYLENE/ANIONIC SURFACTANT SYSTEMS

    EPA Science Inventory

    Winsor Type I (o/w), Type II (w/o), and Type III (middle phase) microemulsions have been generated for water and perchloroethylene (PCE) in combination with anionic surfactants and the appropriate electrolyte concentration. The surfactant formulation was a combination of sodium d...

  18. Visible-light-sensitized dechlorination of perchloroethylene.

    PubMed

    Lin, Chitsan; Jou, Chih-Ju G; Wang, Chih-Lung

    2009-01-01

    An aqueous reaction mixture containing perchloroethylene (PCE), a photosensitizer, and an electron donor was irradiated by visible lamps to facilitate a sunlight-sensitized dechlorination reaction. Various types of lamps, electron donors, and photosensitizers were examined, to compare the rates of dechlorination. Of the six photosensitizers evaluated, methylene blue was the most effective. Electron donors varied in effectiveness, as follows: trimethylamine > triethylamine > tributylamine. The intermediates and reaction products were identified by a purge-and-trap gas chromatography mass spectrometer system. The photosensitized dechlorination method degraded PCE via an electron-transfer-relay mechanism. Degradation products identified were trichloroethylene, dichloroethylenes, and chloroethylene. It seems a sequential dechlorination pathway was followed. The PCE dechlorination in a natural sunlight irradiation test was shown to be more effective than any of the simulated visible light sources. The result supports the feasibility of future development of solar-powered dechlorination remediation systems with the use of sunlight, nontoxic dyes, and electron donors. PMID:19280902

  19. Effect of temperature on perchloroethylene dechlorination by a methanogenic consortium

    SciTech Connect

    Gao, J.; Skeen, R.S.; Hooker, B.S.

    1995-04-01

    The effect of temperature on the kinetics of growth, substrate metabolism, and perchloroethylene (PCE) dechlorination by a methanogenic consortium is reported. In all cases, a simple kinetic model accurately reflected experimental data. Values for the substrate and methane yield coefficients, and the maximum specific growth rate are fairly consistent at each temperature. Also, the substrate and methane yield coefficients show little temperature sensitivity. In contrast, both the maximum specific growth rate and the PCE dechlorination yield coefficient (Y{sub PCE}) are temperature dependent.

  20. Contamination of ground water by PCE - A national perspective

    USGS Publications Warehouse

    Moran, M.J.; Delzer, G.C.

    2006-01-01

    Perchloroethylene (PCE) has physical and chemical properties that make it likely to persist in groundwater if released to the environment. The US Geological Survey has collected or compiled data on the occurrence of PCE in groundwater from major aquifers around the US. These data represent the occurrence of PCE in the groundwater resource as a whole and not occurrence at specific release sites. PCE was detected at measurable concentrations in nearly one in 10 wells in major aquifers throughout the country. Trichloroethylene was found most commonly with PCE and its presence may be due, in part, to reductive dechlorination of PCE. This is an abstract of a paper presented at the Petroleum Hydrocarbons and Organic Chemicals in Ground Water: Prevention, Assessment, and Remediation Conference (Houston, TX 11/6-7/2006).

  1. ACUTE NEUROTOXIC EFFECTS OF INHALED PERCHLOROETHYLENE ON PATTERN VISUAL EVOKED POTENTIALS AS A FUNCTION OF EXPOSURE AND ESTIMATED BLOOD AND BRAIN CONCENTRATION.

    EPA Science Inventory

    Previous experiments have shown the effects of acute inhalation exposure to trichloroethylene (TCE) and toluene are related to the target tissue concentration at the time of testing. The current studies examined exposure to another volatile organic compound, perchloroethylene (P...

  2. Reductive dechlorination of tetrachloroethylene (PCE) catalyzed by cyanocobalamin

    SciTech Connect

    Habeck, B.D.; Sublette, K.L.

    1995-12-31

    A biomimetic system has been developed for the reductive dechlorination of tetrachloroethylene (PCE). PCE was dechlorinated to trichloroethylene (TCE) and 1,2-dichloroethylene (DCE) in the presence of dithiothreitol or Ti (III) citrate and catalytic amounts of cyanocobalamin in both homogeneous reaction mixtures and packed bed reactor systems. In packed bed reactors with Ti (III) citrate as the reductant, PCE (0.18 mM) conversion averaged 55% at residence times of 1.75 and 3.5 h. The product distribution was 94% TCE and 6% DCE at the lower residence time. DCE formation increased to 45% at the higher residence time. No reduction of PCE was observed in the absence of cyanocobalamin. This system may be useful as a means of pretreatment of halogenated aliphatic hydrocarbons in advance of biological treatment.

  3. DEVELOPMENT OF A PHYSIOLOGICALLY BASED PHARMACOKINETIC MODEL FOR PERCHLOROETHYLENE USING TISSUE CONCENTRATION-TIME DATA

    EPA Science Inventory

    The tissue disposition of perchloroethylene (PCE) was characterized experimentally in rats in order to: 1) btain input parameters from in vivo data for the development of a physiologically-based pharmacokinetic (PBPK) model; and 2) use the PBPK model to predict the deposition of ...

  4. PCE treatment in saturated soil columns: Methanogens in sequence with methanotrophs

    SciTech Connect

    Fogel, S.; Findlay, M.; Lewis, R.; Groher, D.

    1995-12-31

    Perchloroethylene (PCE) was reductively dechlorinated under anaerobic conditions in a continuous-flow, saturated soil column. The column was inoculated by a culture known to dechlorinate PCE to ethylene. Methanol was used as the source of carbon and energy. Column conditions were modified to optimize the reaction time and conversion rate of PCE to ethylene. After 200 days of continuous operation, PCE was converted to vinyl chloride (60%) and ethylene (40%) after 2 h of contact time. Sequential treatment by an aerobic, methanotrophic column was used for treatment of vinyl chloride produced during reductive dechlorination of PCE. Field application for the use of this technology for in situ treatment of PCE-contaminated saturated soils and aquifers is discussed.

  5. PROPERTY CHANGES IN AQUEOUS SOLUTIONS DUE TO SURFACTANT TREATMENT OF PCE: IMPLICATIONS TO GEOPHYSICAL MEASUREMENTS

    EPA Science Inventory

    Select physicochemical properties of aqueous solutions composed of surfactants, dye, and

    perchloroethylene (PCE) were evaluated through a response surface quadratic design

    model of experiment. Nine surfactants, which are conventionally used in the

    remediation...

  6. A mass balance study of the phytoremediation of perchloroethylene-contaminated groundwater

    PubMed Central

    James, C. Andrew; Xin, Gang; Doty, Sharon L.; Muiznieks, Indulis; Newman, Lee; Strand, Stuart E.

    2010-01-01

    A mass balance study was performed under controlled field conditions to investigate the phytoremediation of perchloroethylene (PCE) by hybrid poplar trees. Water containing 7–14 mg L?1 PCE was added to the test bed. Perchloroethylene, trichloroethylene, and cis-dichloroethylene were detected in the effluent at an average of 0.12 mg L?1, 3.9 mg L?1, and 1.9 mg L?1, respectively. The total mass of chlorinated ethenes in the water was reduced by 99%. Over 95% of the recovered chlorine was as free chloride in the soil, indicating near-complete dehalogenation of the PCE. Transpiration, volatilization, and accumulation in the trees were all found to be minor loss mechanisms. In contrast, 98% of PCE applied to an unplanted soil chamber was recovered as PCE in the effluent water or volatilized into the air. These results suggest that phytoremediation can be an effective method for treating PCE-contaminated groundwater in field applications. PMID:19345455

  7. Enhanced perchloroethylene reduction in column systems using surfactant-modified zeolite/zero-valent iron pellets.

    PubMed

    Zhang, Pengfei; Tao, Xian; Li, Zhaohui; Bowman, Robert S

    2002-08-15

    Surfactant- (hexadecyltrimethylammonium, HDTMA) modified zeolite (SMZ)/zero-valent iron (ZVI) pellets having high hydraulic conductivity (9.7 cm s(-1)), high surface area (28.2 m2 g(-1)), and excellent mechanical strength were developed. Laboratory column experiments were conducted to evaluate the performance of the pellets for perchloroethylene (PCE) sorption/reduction under dynamic flow-through conditions. PCE reduction rates with the surfactant-modified pellets (SMZ/ZVI) were three times higher than the reduction rates with the unmodified pellets (zeolite/ZVI). We speculate that enhanced sorption of PCE directly onto iron surface by iron-bound HDTMA and/or an increased local PCE concentration in the vicinity of iron surface due to sorption of PCE by SMZ contributed to the enhanced PCE reduction by the SMZ/ZVI pellets. Trichloroethylene and cis-dichloroethylene production during PCE reduction increased with the surfactant-modified pellets, indicating that the surfactant modification may have favored hydrogenolysis over beta-elimination. PCE reduction rate constants increased as the travel velocity increased from 0.5 to 1.9 m d(-1), suggesting that the reduction of PCE in the column systems was mass transfer limited. PMID:12214654

  8. ACUTE BEHAVIORAL EFFECTS OF INHALED PERCHLOROETHYLENE IN RATS ARE DIRECTLY RELATED TO ITS CONCENTRATION IN THE BRAIN.

    EPA Science Inventory

    Perchloroethylene (PCE) is a volatile organic compound (VOC), frequently used in dry cleaning processes, that is currently being assessed by EPA for its risk to human health. Many VOCs are acutely neurotoxic and have been shown to affect attentional processes in humans and animal...

  9. EMISSIONS OF PERCHLOROETHYLENE FROM DRY CLEANED FABRICS

    EPA Science Inventory

    A study was conducted to evaluate the emissions of perchloroethylene (tetrachloroethylene) from dry cleaned fabrics to determine: (a) how the introduction of fresh dry cleaning into a home affects the indoor concentration of perchloroethylene, and (b) the effectiveness of ‘airing...

  10. Studies on the use of perchloroethylene as a heavy medium for the removal of pyrites from coal

    SciTech Connect

    Thome, T.L.; Fullerton, K.L.; Lee, S.

    1996-12-31

    Previous studies have shown that perchloroethylene (PCE) shows promise for use as a heavy medium for the removal of pyrites from fine coal. The studies are continued here, as the coal cleaning effectiveness of mixtures of PCE and kerosene are investigated. Float/sink experiments are run for different medium densities obtained by varying the proportions of PCE and kerosene. The effectiveness of the cleaning process is judged by data taken from a long tube sampling apparatus. Among the variables investigated are medium density, residence time, and solvent-to-coal ratio. The data is used to support scale-up predictions for a plant apparatus.

  11. Assessment of Exposure to Perchloroethylene and its Clinical Repercussions for 50 Dry-Cleaning Employees.

    PubMed

    Lucas, D; Hervé, A; Lucas, R; Cabioch, C; Capellmann, P; Nicolas, A; Bodenes, A; Jegaden, D

    2015-11-01

    The purpose of this article is the assessment of occupational exposure to perchloroethylene (PCE) and its clinical repercussions for dry-cleaning employees. The authors measured atmospheric levels of PCE and blood levels in a population of 50 exposed employees then conducted a study of clinical symptomatology in exposed and non-exposed subjects linked with this solvent. Fifty employees and 95 controls were studied. The median value of atmospheric PCE was 7 ppm (0.22-33), and the median blood level of PCE was 73.6 ?g/l (11.8-144). These levels were correlated statistically to the action of sludge scraping and to the existence of automatic scrapers (p < 0.01). Eight percent of PCE blood levels were higher than the biological levels recently set in France. The exposed population did not show excessive signs of drowsiness nor of pre-narcotic syndrome or other symptoms studied. Dry-cleaning employees were exposed to PCE at atmospheric levels lower than the French and American chronic recommended exposure levels but some results were higher than recommended values. For PCE blood levels for the general working population, results were respectively lower than French and American national recommended levels in 92% and 94% cases. Risk should be considered, however, carefully in women of childbearing age, as 64% exceeded the recommended blood levels for pregnant women. This exposure did not generate any studied neurobehavioral symptomatology. PMID:26011697

  12. Renal function in dry cleaning workers exposed to perchloroethylene

    SciTech Connect

    Solet, D.; Robins, T.G. )

    1991-01-01

    Perchloroethylene (PCE) is a widely used dry cleaning and degreasing solvent. Although there is evidence in animals and humans for renal effects at extremely high doses, there are few studies of its potential renal toxicity at typical occupational concentrations. This study reports on the relationship of PCE in breath and estimates of chronic exposure with the urinary ratios of total urinary protein, albumin, and n-acetyl-glucosaminidase (NAG) to creatinine in dry cleaning workers exposed to PCE. Regression models including one or more exposure variables, demographic variables, mean arterial blood pressure (MAP), and the presence of diseases affecting kidney function were examined. Urine samples, breath samples, exposure histories, and medical histories were obtained from 192 dry cleaning workers. The results failed to demonstrate any consistent relationship between exposure and renal outcome variables. However, protein/creatinine and albumin/creatinine were significantly, although weakly and positively, associated with MAP; NAG/creatinine was weakly but significantly positively associated with age; mean NAG/creatinine was also higher in non-whites. The reasons why an association between exposure and renal outcome was not found are discussed.

  13. Experimental Assessment of Bioenhanced Dissolution and Microbial Distribution During PCE-NAPL Source Zone Bioremediation

    NASA Astrophysics Data System (ADS)

    Amos, B. K.; Suchomel, E. J.; Pennell, K. D.; Loeffler, F. E.

    2006-12-01

    Specialized anaerobic bacteria are capable of detoxifying tetrachloroethene (PCE) and trichloroethene (TCE) as well as enhancing contaminant dissolution from dense nonaqueous phase liquid (DNAPL) source zones. Thus, the microbial reductive dechlorination process has emerged as a promising remedial technology for PCE- and TCE-DNAPL source zones. However, the effects of microbial activity and distribution within DNAPL source zones on dissolution enhancement remain poorly understood. Experiments to evaluate the activity and distribution of dechlorinating populations in the immediate vicinity of a PCE-NAPL source zone were performed in a one-dimensional soil column containing a 10 cm NAPL (0.25 mol/mol PCE in hexadecane) source zone and a 50 cm down-gradient plume region. In one column experiment, Sulfurospirillum multivorans, a PCE-to-cis-DCE dechlorinating isolate, transformed PCE to cis-DCE with an approximate 4-fold cumulative dissolution enhancement. Quantitative real-time PCR (qPCR) correlated activity and distribution of S. multivorans with enhanced PCE dissolution. Similar NAPL dissolution enhancement was observed in another column augmented with a PCE-to-ethene dechlorinating consortium containing Dehalococcoides, Dehalobacter, and Geobacter populations, with PCE dechlorinated primarily to cis-DCE and vinyl chloride. Geobacter and Dehalococcoides populations were detected within the source zone, and increases in the dechlorinator population sizes coincided spatially with increased formation of dechlorination products. Experimental results indicate that mass transfer enhancement by microbial reductive dechlorination within NAPL source zones is possible, and that the distribution of relevant microbial populations directly affects dissolution enhancement. Ongoing work focuses on evaluating the distribution of specific Dehalococcoides strains in the vicinity of PCE-NAPL.

  14. Removal of perchloroethylene from a layered soil system by steam flushing

    SciTech Connect

    She, H.Y.; Sleep, B.E.

    1999-10-01

    Steam flushing experiments were conducted in a two-dimensional chamber containing two layers of F75 silica sand separated by a layer of finer F110 silica sand. Perchloroethylene (PCE), which had spilled into the chamber under water-saturated conditions, formed a pool on the F110 sand layer. Steam was injected above the F110 sand layer. Temperatures, moisture content, and PCE concentrations in the chamber were monitored. Samples, taken from the various locations in the sand chamber, indicated that complete removal of PCE from the steam zone was achieved, with an 84% overall recovery. Some downward displacement of PCE-contaminated water through the F110 sand layer was observed and a small amount of gravity override occurred. Channeling of steam was minimal. The experiment indicates that steam flushing may be used successfully for removal of PCE from relatively homogeneous soils. Issues of gravity override and downward mobilization of contaminants must be considered in applying steam flushing at the field scale.

  15. TRICHLOROETHYLENE (TCE) ISSUE PAPERS

    EPA Science Inventory

    These issue papers are a part of EPA's effort to develop a trichloroethylene (TCE) human health risk assessment. These issue papers were developed by EPA to provide scientific and technical information to the National Academy of Sciences (NAS) for use in developing their advice ...

  16. HORIZONTAL LASAGNA TO BIOREMEDIATE TCE

    EPA Science Inventory

    Removal of TCE from these tight clay soils has been technically difficult and expensive. However, the LASAGNATM technique allows movement of the TCE into treatment zones for biodegradation or dechlorination in place, lessening the costs and exposure to TCE. Electroosmosis was c...

  17. Structure of TCE Pacific Northwest National Laboratory

    E-print Network

    Baumgartner, Gerald

    many-electron theory TCE is written in Python® programming language TCE implements the working Download the latest Python® from www.python.org (free) TCE codes (aee.py, ccc.py, oce.py, tce.py) will run NWChem #12;How TCE can be used ­­­ GUI based #12;How TCE can be used ­­­ text based cf) Auer

  18. MEASUREMENT OF PERCHLOROETHYLENE IN AMBIENT AIR

    EPA Science Inventory

    Perchloroethylene (i.e., tetrachloroethylene) is an organic solvent widely used in dry cleaning and industrial metal degreasing operations. Short-term field studies were conducted in each of three major metropolitan areas which were selected on the basis of the number, density an...

  19. NEUROTOXICITY OF TETRACHLOROETHYLENE (PERCHLOROETHYLENE): DISCUSSION PAPER

    EPA Science Inventory

    This paper is a background document for a meeting of neurotoxicity experts to discuss the central nervous system effects of exposure to perchloroethylene (perc). The document reviews the literature on neurological testing of people exposed to perc occupationally in dry cleanin...

  20. Superfund Record of Decision (EPA Region 7): Des Moines TCE, Des Moines, Polk County, Iowa, July 1986. Final report

    SciTech Connect

    Not Available

    1986-07-21

    The Des Moines TCE site includes the underground infiltration gallery used by the Des Moines Water Works (DMWW) as a source of the public water supply. The site was discovered in 1984 after trichloroethylene (TCE) was detected in the city's public water supply. The Dico Company disposed of an unknown quantity of oily waste sludge containing TCE onto their parking lot for dust control and into a drainage ditch on their property. The primary contaminants of concern include: TCE, PCE, 1,2-dichloroethane, vinyl chloride. The selected remedial action for this site includes: extraction wells to collect the contaminated ground water; isolation of the northern-most section of the north gallery; treatment of the ground water through air stripping to remove 96% of the TCE; discharge of the treated water to the Raccoon River; operation of the west extraction wells until established effluent levels are achieved for four consecutive months.

  1. A study of the effect of perchloroethylene exposure on semen quality in dry cleaning workers

    SciTech Connect

    Eskenazi, B.; Wyrobek, A.J.; Fenster, L.; Katz, D.F.; Sadler, M.; Lee, J.; Hudes, M.; Rempel, D.M. )

    1991-01-01

    The purpose of this investigation was to determine the effects of perchloroethylene (PCE) exposure on human semen quality. We compared the semen quality of 34 dry cleaners with that of 48 laundry workers. We examined the relationships of 17 semen parameters to expired air levels of PCE and to an index of exposure based on job tasks in the last three months. The average sperm concentration was over 80 million for both dry cleaners and laundry workers, but approximately one-quarter of each group was oligospermic. The overall percentage of abnormal forms was similar for the two groups; however, sperm of dry cleaners were significantly more likely to be round (t = -3.29, p = 0.002) and less likely to be narrow (t = 2.35, p = 0.02) than the sperm of laundry workers. These effects were dose-related to expired air levels and to the exposure index after controlling for potential confounders (e.g., heat exposure). The average percent motile sperm for both groups was slightly over 60%; however, sperm of dry cleaners tended to swim with greater amplitude of lateral head displacement (ALH) than those of laundry workers (t = -1.73, p = 0.09), and level of PCE in expired air was a significant predictor of ALH in the multiple regression model (t = 2.00, p = 0.05). In addition, exposure index was a significant negative predictor of the sperm linearity parameter (t = -2.57, p = 0.01). These results suggest that occupational exposures to PCE can have subtle effects on sperm quality. Additional analyses are required to determine whether these effects are associated with changes in fertility.

  2. The PACSAT Communications Experiment (PCE)

    SciTech Connect

    Not Available

    1993-02-12

    While VITA (Volunteers in Technical Assistance) is the recognized world leader in low earth orbiting (LEO) satellite technology (below 1 GHz), its involvement in communications technologies is to facilitate renewable energy technology transfer to developing countries. A communications payload was incorporated into the UoSat 2 satellite (Surrey Univ., UK), launched in 1984; a prototype satellite (PCE) was also launched Jan 1990. US DOE awarded a second grant to VITA to design and test the prototype ground stations (command and field), install field ground stations in several developing country sites, pursue the operational licensing process, and transfer the evaluation results to the design of an operating system. This report covers the principal tasks of this grant.

  3. Effect of dechlorinating bacteria on the longevity and composition of PCE-containing nonaqueous phase liquids under equilibrium dissolution conditions

    SciTech Connect

    Carr, C.S.; Garg, S.; Hughes, J.B.

    2000-03-15

    The influence of dechlorinating microorganisms on PCE and its reduced end products in the presence of a PCE-containing nonaqueous phase liquid (NAPL) was investigated. Experiments were conducted in continuous-flow stirred-tank reactors (CFSTRs) containing a mixed PCE dechlorinating culture and a model NAPL consisting of PCE and tridecane. Comparisons between biotic and abiotic CFSTRs demonstrated that dechlorination resulted in a factor of 14 increase in PCE removal rates from the NAPL. The formation of dechlorination daughter products trichloroethene and cis-dichloroethene were observed, and cis-dichloroethene was not dechlorinated further. Partitioning of daughter products between phases caused temporal changes in the chlorinated ethenes distribution within the NAPL. The combined effects of dissolution and dechlorination on the removal of chlorinated ethenes from the NAPL were described using a mathematical model that approximated dechlorination as a pseudo-first-order process. Pseudo-first-order dechlorination rate coefficients for PCE and TCE were determined and were 0.18 and 0.27 h{sup {minus}1}, respectively. It was determined that total chlorinated ethenes removal from the NAPL would be achieved in 13 days in biotic CFSTRs, as compared to 77 days in the abiotic CFSTRs--corresponding to an 83% reduction in longevity of the chlorinated ethenes component of the NAPL.

  4. PHASE-TRANSFER-CATALYST APPLIED TO THE OXIDATION OF TRICHLOROETHYLENE BY POTASSIUM PERMANGANATE

    EPA Science Inventory

    Chlorinated ethylenes such as trichloroethylene (TCE) and perchloroethylene (PCE) are common contaminants (Plumb 1991; Westrick et al., 1984). They opccur in the subsurface as zones of residual saturation or occasionally as free products. Because of their inherently low solubil...

  5. A convenient method for the quantitative determination of elemental sulfur in coal by HPLC analysis of perchloroethylene extracts

    USGS Publications Warehouse

    Buchanan, D.H.; Coombs, K.J.; Murphy, P.M.; Chaven, C.

    1993-01-01

    A convenient method for the quantitative determination of elemental sulfur in coal is described. Elemental sulfur is extracted from the coal with hot perchloroethylene (PCE) (tetrachloroethene, C2Cl4) and quantitatively determined by HPLC analysis on a C18 reverse-phase column using UV detection. Calibration solutions were prepared from sublimed sulfur. Results of quantitative HPLC analyses agreed with those of a chemical/spectroscopic analysis. The HPLC method was found to be linear over the concentration range of 6 ?? 10-4 to 2 ?? 10-2 g/L. The lower detection limit was 4 ?? 10-4 g/L, which for a coal sample of 20 g is equivalent to 0.0006% by weight of coal. Since elemental sulfur is known to react slowly with hydrocarbons at the temperature of boiling PCE, standard solutions of sulfur in PCE were heated with coals from the Argonne Premium Coal Sample program. Pseudo-first-order uptake of sulfur by the coals was observed over several weeks of heating. For the Illinois No. 6 premium coal, the rate constant for sulfur uptake was 9.7 ?? 10-7 s-1, too small for retrograde reactions between solubilized sulfur and coal to cause a significant loss in elemental sulfur isolated during the analytical extraction. No elemental sulfur was produced when the following pure compounds were heated to reflux in PCE for up to 1 week: benzyl sulfide, octyl sulfide, thiane, thiophene, benzothiophene, dibenzothiophene, sulfuric acid, or ferrous sulfate. A sluury of mineral pyrite in PCE contained elemental sulfur which increased in concentration with heating time. ?? 1993 American Chemical Society.

  6. FTIR quantification of industrial hydraulic fluids in perchloroethylene

    NASA Technical Reports Server (NTRS)

    Mehta, Narinder K.

    1993-01-01

    The purpose of this summer research project was to investigate whether perchloroethylene can be used as a solvent for the quantitative analysis of industrial hydraulic fluids by infrared spectroscopy employing Beer's law. Standard calibration curves using carbon-hydrogen stretching (generic) and ester absorption peaks were prepared for a series of standard dilutions at low ppm levels of concentration of seven hydraulic fluids in perchloroethylene. The absorbance spectras were recorded with 1.5-10 mm fixed and variable path length sample cells made of potassium bromide. The results indicate that using ester infrared spectral peak, it is possible to detect about 20 ppm of the hydraulic fluid in perchloroethylene.

  7. Physical cleaning of coal using perchloroethylene as heavy medium

    SciTech Connect

    Thome, T.L.; Fullerton, K.L.; Lee, S.

    1994-12-31

    Use of perchloroethylene solvent in the physical cleaning of finely crushed coal has been studied in a glass tube batch apparatus. The density of perchloroethylene makes it an ideal heavy medium for float/sink separation processes. Float/sink removal of pyrites and mineral matter has been studied to determine the effect of process variables. The effect of various parameters is studied, such as mean residence time, solvent-to-coal ratio, and heavy medium density. The density of the perchloroethylene solvent is varied using kerosene to study the effects of medium density. The test results are used to assess the effectiveness of perchloroethylene as a heavy medium for the removal of pyritic sulfur from the coal. The data is used to develop a model of the process for use in scale-up and plant studies.

  8. HORIZONTAL LASAGNA^TM TO BIOREMEDIATE TCE

    EPA Science Inventory

    Removal of TCE from these tight clay soils has been technically difficult and expensive. However, the LASAGNA technique allows movement of the TCE into treatment zones for biodegradation or dechlorination in place, lessening the costs and exposure to TCE.

    Electroosmosis wa...

  9. TEMPERATURE DEPENDENCE OF THE EMISSION OF PERCHLOROETHYLENE FROM DRY CLEANED FABRICS

    EPA Science Inventory

    The article discusses an evaluation of the emission of perchloroethylene (tetrachloroethylene) from freshly dry cleaned fabrics using small environment test chambers. he temperature dependence of the release of perchloroethylene was evaluated over a temperature range of 20 to 45 ...

  10. Graphene packed needle trap device as a novel field sampler for determination of perchloroethylene in the air of dry cleaning establishments.

    PubMed

    Heidari, Mahmoud; Bahrami, Abdolrahman; Ghiasvand, Ali Reza; Emam, Maryam Rafiei; Shahna, Farshid Ghorbani; Soltanian, Ali Reza

    2015-01-01

    In this paper we describe the application of a needle trap microextraction device packed with graphene nanoplatelets for the sampling and analysis of perchloroethylene in dry cleaning. The study was carried out in two phases. First the parameters for the sampling and analysis of perchloroethylene by NTD were evaluated and optimized in the laboratory. Then the sampler was used to determine the levels of perchloroethylene in a dry-cleaning shop. In the laboratory phase of the study the performance of the NTD packed with the proposed sorbent was examined in a variety of sampling conditions to evaluate the technique. The technique was also compared with NTDs packed with PDMS as well as SPME with Carboxen/PDMS-coated fibers. Both the NTDs and SPME performed better at lower sampling temperatures and relative humidity levels. The post-sampling storage times for a 95% recovery of the analyte were 5, 5 and 3 days for NTD-graphene, NTD-PDMS and SPME-CAR/PDMS respectively. The optimum desorption time was 3 min for NTDs packed with either graphene or PDMS and 1 min for SPME-CAR/PDMS. The limits of detection for the GC/MS detection system were 0.023 and 0.25 ng mL(-1) for NTDs packed with graphene and PDMS and 0.014 ng mL(-1) for SPME coated with CAR/PDMS. In the second stage of the study the evaluated technique was applied to the sampling and analysis of perchloroethylene in dry cleaning. In this environment the performance of the NTD-graphene as a field sampler for PCE was similar to that of the SPME-CA/PDMS, and better than the NIOSH 1003 method which had greater measurement variations. The results show that a NTD packed with carbonic graphene nanoplatelets and used as an active exhaustive sampling technique is effective for determination of VOC and HVOC occupational/environmental pollutants in air. PMID:25281085

  11. Potential of the TCE-degrading endophyte Pseudomonas putida W619-TCE to improve plant growth and reduce TCE phytotoxicity and evapotranspiration in poplar cuttings

    SciTech Connect

    Weyens, N.; van der Lelie, D.; Truyens, S.; Dupae, J.; Newman, L.; Taghavi, S.; Carleer, R.; Vangronsveld, J.

    2010-09-01

    The TCE-degrading poplar endophyte Pseudomonas putida W619-TCE was inoculated in poplar cuttings, exposed to 0, 200 and 400 mg l{sup -1} TCE, that were grown in two different experimental setups. During a short-term experiment, plants were grown hydroponically in half strength Hoagland nutrient solution and exposed to TCE for 3 days. Inoculation with P. putida W619-TCE promoted plant growth, reduced TCE phytotoxicity and reduced the amount of TCE present in the leaves. During a mid-term experiment, plants were grown in potting soil and exposed to TCE for 3 weeks. Here, inoculation with P. putida W619-TCE had a less pronounced positive effect on plant growth and TCE phytotoxicity, but resulted in strongly reduced amounts of TCE in leaves and roots of plants exposed to 400 mg l{sup -1} TCE, accompanied by a lowered evapotranspiration of TCE. Dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), which are known intermediates of TCE degradation, were not detected. The endophyte P. putida W619-TCE degrades TCE during its transport through the xylem, leading to reduced TCE concentrations in poplar, and decreased TCE evapotranspiration.

  12. IRIS TOXICOLOGICAL REVIEW OF TETRACHLOROETHYLENE (PERCHLOROETHYLENE) (INTERAGENCY SCIENCE DISCUSSION DRAFT)

    EPA Science Inventory

    EPA is releasing the draft report, Toxicological Review of Tetrachloroethylene (Perchloroethylene), that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the IRIS Assessment...

  13. Degradation of Perchloroethylene and Dichlorophenol by Pulsed-Electric

    E-print Network

    Wood, Thomas K.

    -stage sys- tem which dechlorinates the halogenated pollutants, 2,4- dichlorophenol and perchloroethylene, showing that both cell densities and overall dichlorophenol dechlorination were highly dependent upon at 40­45 kV and 1.2 kHz) while P. mendocina KR1 in the second stage increased dechlorination to 90

  14. INHIBITORY EFFECTS OF PERCHLOROETHYLENE ON HUMAN NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS.

    EPA Science Inventory

    Perchloroethylene (PERC) is a volatile organic solvent with a variety of industrial uses. PERC exposure has been shown to cause adverse neurological effects including deficits in vision and memory in exposed individuals. Despite knowledge of these effects, the mechanisms by whi...

  15. REMEDIATION OF SITES CONTAMINATED WITH TCE

    EPA Science Inventory

    Widespread use of trichloroethylene (TCE) in the U.S. has resulted in its frequent detection in soil and groundwater. TCE can become a health hazard after being processed in the human liver; or reductive dehalogenation in the environment may result in production of vinyl chloride...

  16. Phytoremediation of trichloroethene (TCE) using cottonwood trees

    USGS Publications Warehouse

    Jones, S.A.; Lee, R.W.; Kuniansky, E.L.

    1999-01-01

    The ability of cottonwood trees for phytoremediation was studied on aerobic shallow groundwater containing TCE. Cottonwood trees were planted over a 0.2-ha area at the Naval Air Station at Fort Worth, TX, in April 1996. Two years later, groundwater chemistry in the terrace alluvial aquifer was changing locally. Dissolved oxygen (DO) concentrations declined at the southern end of the whip plantings while total iron concentration increased. Groundwater chemistry near a mature cottonwood tree ~ 60 m from the caliper trees was different from that observed elsewhere. Anaerobic conditions near the mature cottonwood tree were evident. Reductive dechlorination of TCE occurred in the aquifer near the mature tree, as demonstrated by very small concentration of TCE in groundwater, a small median ratio of TCE to the degradation product cis-1,2-DCE and the presence of vinyl chloride.

  17. Synthetic adsorbent versus GAC for TCE removal

    SciTech Connect

    Hand, D.W.; Herlevich, J.A. Jr.; Perram, D.L.; Crittenden, J.C. )

    1994-08-01

    The performance of a synthetic adsorbent in removing trichloroethene (TCE) from a groundwater containing natural organic matter (NOM) was compared with that of granular activated carbon (GAC). Adsorption equilibrium, kinetic, and pilot-plant experiments were used to compare the adsorbents. Adsorption isotherm studies showed that the synthetic adsorbent had three to four times more TCE capacity than GAC over a TCE concentration range of 10--2,000 [mu]g/L. When preexposed for 24 weeks to a groundwater containing NOM, the synthetic adsorbent showed an average 12% loss in capacity compared with the single-solute isotherm performed on the virgin adsorbent; GAC showed an average 35% loss in its virgin capacity for a preexposed time of only 10 weeks. Rapid small-scale column tests and model calculations predicted pilot-plant effluent profiles for the synthetic adsorbent. The pilot-plant data confirmed that the synthetic adsorbent is more efficient than GAC in removing TCE.

  18. BIODEGRADATION OF PCE AND TCE IN LANDFILL, LEACHATE PREDICTED FROM CONCENTRATIONS OF MOLECULAR HYDROGEN: A CASE STUDY

    EPA Science Inventory

    The Refuse Hideaway Landfill (23-acre) was designed as a "natural attenuation" landfill and no provision was made to collect and treat contaminated water. Natural biological degradation through sequential reductive dechlorination had been an important mechanism for natural atten...

  19. Exposure assessment to trichloroethylene and perchloroethylene for workers in the dry cleaning industry.

    PubMed

    Rastkari, Noushin; Yunesian, Masud; Ahmadkhaniha, Reza

    2011-04-01

    Perchloroethylene and trichloroethylene are two particular organochloro compounds, are often used for dry-cleaning. In the present study the excretion of urinary Perchloroethylene and trichloroethylene were evaluated as biomarkers of exposure to these compounds. The mean value of Perchloroethylene in breathing zone and the total Perchloroethylene uptake during the work shift of the three groups of dry-cleaning workers according to the capacity of the dry-cleaning machine (8, 12 and 18 kg) were 31.04, 50.87 and 120.99 mg m(-3) and 11.46, 22.6 and 41.6 ?g L(-1), respectively, which were significantly greater than the occupationally nonexposed groups. A good correlation (r = 0.907) between the mean values of Perchloroethylene in breathing zone and the urinary concentrations was observed. PMID:21416139

  20. Sulfur cement production using by products of the perchloroethylene coal cleaning process and the FC4-1 cleaned soil

    SciTech Connect

    Bassam Masri, K.L.; Fullerton, S.L.

    1995-12-31

    An introductory set of experiments to show the feasibility of making sulfur cement were carried out at the University of Akron according to Parrett and Currett`s patent which requires the use of sulfur, a filler, a plasticizer, and a vulcanization accelerator. Small blocks of cement were made using byproducts of the perchloroethylene coal cleaning process. Extracted elemental and organic sulfur, ash and mineral matters from the float sink portion of the PCE process, and FC4-1 cleaned soil were used as substitutes for sulfur and filler needed for the production of sulfur cement. Leaching tests in different solutions and under different conditions were conducted on the sulfur blocks. Other tests such as strength, durability, resistance to high or low temperatures will be conducted in the future. Sulfur cement can be used as a sealing agent at a joint, roofing purposes, forming ornamental figures, and coating of exposed surfaces of iron or steel. When mixed with an aggregate, sulfur concrete is formed. This concrete can be used for structural members, curbings, guthers, slabs, and can be precast or cast at the job site. An advantage of sulfur cement over Portland cement is that it reaches its design strength in two to three hours after processing and it can be remelted and recast.

  1. Health Assessment Document for Tetrachloroethylene (Perchloroethylene) (Final Report)

    EPA Science Inventory

    Tetrachloroethylene (PCE) is a volatile solvent with important commercial applications. It has been detected in the ambient air of a variety of urban and nonurban areas of the United States. It has less frequently been detected in water but has been monitored generally at levels ...

  2. SOURCES, EMISSION AND EXPOSURE TO TRICHLOROETHYLENE (TCE) AND RELATED CHEMICALS

    EPA Science Inventory

    This report documents the sources, emission, environmental fate and exposures for TCE, some of its metabolites, and some other chemicals known to produce identical metabolites. The major findings for TCE are:


    1. The primary sources releasing TCE to the environment ...

    2. Enhanced dissolution of TCE in NAPL by TCE-degrading bacteria in wetland soils.

      PubMed

      Lee, Sangjin

      2007-06-25

      The influence of trichloroethene (TCE) dechlorinating mixed cultures in dissolution of TCE in nonaqueous phase liquid (NAPL) via biodegradation was observed. Experiments were conducted in batch reactor system with and without marsh soils under 10 and 20 degrees C for 2 months. The dissolution phenomenon in biotic reactors containing mixed cultures was showed temporal increases compared to abiotic reactors treated with biocide. Effective NAPL-water transfer rate (K(m)) calculated in this study showed more than four times higher in biotic reactors than that in abiotic reactors. The results might be attributed to the biologically enhanced dissolution process via dechlorination in reactors. Temperature would be a factor to determine the dissolution rate by controlling bacterial activity. The TCE dechlorination occurred even in an interface of TCE-NAPL that demonstrated no previous TCE biodegradation, suggesting that microbes may be useful in developing source-zone bioremediation system. In conclusion, dechlorinating mixed culture could enhance dissolution in NAPL that may be useful in the application of source zone bioremediation. PMID:17126487

    3. PCE solubilization and mobilization by commercial humic acid

      NASA Astrophysics Data System (ADS)

      Johnson, William P.; John, W. Wynn

      1999-01-01

      In this paper, comparison is made of terms describing solubilization of hydrophobic organic compounds (HOC) by dissolved humic substances (DHS) and commercial non-ionic surfactants. This paper examines the ability of a commercial humic acid (Aldrich humic acid) to solubilize and mobilize tetrachlorothene (PCE) residual in porous media. The constant for solubilization of PCE by Aldrich humic acid is shown to be a factor of two to thirty times less than that published for dodecyl alcohol ethoxylate surfactants, showing that Aldrich humic acid is less capable than some non-ionic surfactants at solubilizing residual PCE. The depression of PCE-water interfacial tension in the presence of DHS is shown to be significantly less than published values for a non-ionic surfactant, and surfactant mixtures, indicating that the DHS used in this study is less prone to cause mobilization of non-aqueous phase liquids relative to surfactants. Several possible advantages of DHS use in the remediation of subsurface media contaminated with HOC are described, including the ability of DHS to solubilize HOC irrespective of the DHS concentration, and potential lesser tendency of DHS to depress the interfacial tension between non-aqueous phases and water relative to surfactants (an advantage when mobilization is undesired).

    4. Molecular Biomarker-Based Biokinetic Modeling of a PCE-Dechlorinating and Methanogenic Mixed Culture

      SciTech Connect

      Heavner, Gretchen L.; Rowe, Annette R.; Mansfeldt, Cresten B.; Pan, Ju Khuan; Gossett, James M.; Richardson, Ruth E.

      2013-04-16

      Bioremediation of chlorinated ethenes via anaerobic reductive dechlorination relies upon the activity of specific microbial populations ? most notably Dehalococcoides (DHC) strains. In the lab and field Dehalococcoides grow most robustly in mixed communities which usually contain both fermenters and methanogens. Recently, researchers have been developing quantitative molecular biomarkers to aid in field site diagnostics and it is hoped that these biomarkers could aid in the modeling of anaerobic reductive dechlorination. A comprehensive biokinetic model of a community containing Dehalococcoides mccartyi (formerly D. ethenogenes) was updated to describe continuously fed reactors with specific biomass levels based on quantitative PCR (qPCR)-based population data (DNA and RNA). The model was calibrated and validated with subsets of chemical and molecular biological data from various continuous feed experiments (n = 24) with different loading rates of the electron acceptor (1.5 to 482 ?eeq/L-h), types of electron acceptor (PCE, TCE, cis-DCE) and electron donor to electron acceptor ratios. The resulting model predicted the sum of dechlorination products vinyl chloride (VC) and ethene (ETH) well. However, VC alone was under-predicted and ETH was over predicted. Consequently, competitive inhibition among chlorinated ethenes was examined and then added to the model. Additionally, as 16S rRNA gene copy numbers did not provide accurate model fits in all cases, we examined whether an improved fit could be obtained if mRNA levels for key functional enzymes could be used to infer respiration rates. The resulting empirically derived mRNA “adjustment factors” were added to the model for both DHC and the main methanogen in the culture (a Methanosaeta species) to provide a more nuanced prediction of activity. Results of this study suggest that at higher feeding rates competitive inhibition is important and mRNA provides a more accurate indicator of a population’s instantaneous activity than 16S rRNA gene copies alone as biomass estimates.

    5. Engineering TCE-Degrading Rhizobacteria for Heavy Metal

      E-print Network

      Chen, Wilfred

      to be a suspected carcinogen, and its wide- spread usage has made TCE one of the most common groundwater pollutants are currently co-contami- nated with organic pollutants such as trichloroethene (TCE) and heavy metals that will survive and thrive in soil heavily polluted with heavy metals. In this work, a gene coding for the metal

    6. GASEOUS BEHAVIOR OF TCE (TRICHLOROETHYLENE) OVERLYING A CONTAMINATED AQUIFER

      EPA Science Inventory

      Shallow soil gas (<2 meters deep) was collected and analyzed for trichloroethylene (TCE) to determine the relationship with ground-water contamination directly below. The gaseous TCE plume was mapped with 46 probes and spanned three orders of magnitude in concentration (<0.001 to...

    7. Complex electrical resistance tomography of a subsurface PCE plume

      SciTech Connect

      Ramirez, A.; Daily, W,; LeBrecque, D.

      1996-01-01

      A controlled experiment was conducted to evaluate the performance of complex electrical resistivity tomography (CERT) for detecting and delineating free product dense non-aqueous phase liquid (DNAPL) in the subsurface. One hundred ninety liters of PCE were released at a rate of 2 liters per hour from a point 0.5 m below ground surface. The spill was conducted within a double walled tank where saturated layers of sand, bentonite and a sand/bentonite mixture were installed. Complex electrical resistance measurements were performed. Data were taken before the release, several times during, and then after the PCE was released. Magnitude and phase were measured at 1 and 64 Hz. Data from before the release were compared with those during the release for the purpose of imaging the changes in conductivity resulting from the plume. Conductivity difference tomographs showed a decrease in electrical conductivity as the DNAPL penetrated the soil. A pancake-shaped anomaly developed on the top of a bentonite layer at 2 m depth. The anomaly grew in magnitude and extent during the release and borehole television surveys data confirmed the anomaly to be free-product PCE whose downward migration was stopped by the low permeability clay. The tomographs clearly delineated the plume as a resistive anomaly.

    8. Fate and Transport of TCE Solvents Through Saturated Karst Aquifer

      NASA Astrophysics Data System (ADS)

      Padilla, I. Y.; Carmona, M.; Anaya, A. A.

      2014-12-01

      Dense Nonaqueous-Phase Liquids (DNAPLs) are a group of organic compounds that have been a serious problem for groundwater pollution in karst. The industrial production and utilization of these chemicals spread since 1940, and are present at tens of thousands of contaminated sites worldwide. The physic-chemical properties of DNAPLs in conjunction with the hydraulic properties of the karst systems create the perfect condition for DNAPLs to penetrate the epikarst, reach the groundwater, and more within the karst system to zones of potential exposure, such as wells, streams and wetlands. Trichloroethylene (TCE) is the most common DNPAL found in the subsurface environment. This research studies the fate and transport of TCE DNAPL in a karstified limestone physical model (KLPM). Experiments are carried out in KLPM. The KLPM is an enclosed stainless steel tank packed with a rectangular limestone block (15cm x 15cm x 76cm) that simulates a saturated confine karst aquifer. DNAPL experiment involve the injection of 40 ml of pure TCE into steady groundwater flow at the upstream boundary of the KLPM model, while sampling spatially and temporally along the block. Samples are analyzed for TCE on the pure and dissolved phase. Pure TCE is analyzed volumetrically and dissolved phase concentrations are analyze using a High Performance Liquid Chromatography (HPLC). TCE data is used to construct temporal distributions curves (TDCs) at different spatial locations. Results show that pure TCE volumes are collected at the beginnings of the experiment in sampling ports located near the injection port and along preferential flow paths. TCE concentration TDCs show spatial variations related to the limestone block heterogeneously. Rapid response to TCE concentrations is associated with preferential flow paths. Slow response and long tailing of TCE of TCE concentration are associated with diffusive transport in rock matrix and mass transport rates limitations. Bimodal distributions are associated with multiple flow path connectivity. Overall, results show that karstified limestone has a high capacity to rapidly transport, as well as store and slowly release TCE pure and dissolved phase. Response times to TCE concentrations depend on the mode of transport, and region of flow paths.

    9. PERCHLOROETHYLENE (PERC) INHIBITS FUNCTION OF VOLTAGE-GATED CALCIUM CHANNELS IN PHEOCHROMOCYTOMA CELLS.

      EPA Science Inventory

      The industrial solvent perchloroethylene (PERC) is listed as a hazardous air pollutant in the 1990 Ammendments to Clean Air Act and is a known neurotoxicant. However, the mechanisms by which PERC alters nervous system function are poorly understood. In recent years, it has been d...

    10. AMBIENT PERCHLOROETHYLENE LEVELS INSIDE COIN-OPERATED LAUNDRIES WITH DRYCLEANING MACHINES ON THE PREMISES

      EPA Science Inventory

      In this study, ambient perchloroethylene (PERC) levels were measured inside and in the vicinity of six self serve laundries containing coin-type dry cleaning operations. Inside two of the laundries, evaluations of organic vapor monitoring badges were performed in addition to the ...

    11. CATALYTIC STEAM REFORMING OF CHLOROCARBONS: TRICHLOROETHANE, TRICHLOROETHYLENE AND PERCHLOROETHYLENE. (R826694C633)

      EPA Science Inventory

      The effective destruction of trichloroethane, trichloroethylene and perchloroethylene by steam reforming with a commercial nickel catalyst has been demonstrated. Conversion levels of up to 0.99999 were attained in both laboratory and semi-pilot experiments, with the products c...

    12. IRIS Toxicological Review of Trichloroethylene (TCE) (External Review Draft)

      EPA Science Inventory

      EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of Trichloroethylene (TCE) that when finalized will appear on the Integrated Risk Information System (IRIS) database.

    13. Inter-Domain Redundancy Path Computation Methods Based on PCE

      NASA Astrophysics Data System (ADS)

      Hayashi, Rie; Oki, Eiji; Shiomoto, Kohei

      This paper evaluates three inter-domain redundancy path computation methods based on PCE (Path Computation Element). Some inter-domain paths carry traffic that must be assured of high quality and high reliability transfer such as telephony over IP and premium virtual private networks (VPNs). It is, therefore, important to set inter-domain redundancy paths, i. e. primary and secondary paths. The first scheme utilizes an existing protocol and the basic PCE implementation. It does not need any extension or modification. In the second scheme, PCEs make a virtual shortest path tree (VSPT) considering the candidates of primary paths that have corresponding secondary paths. The goal is to reduce blocking probability; corresponding secondary paths may be found more often after a primary path is decided; no protocol extension is necessary. In the third scheme, PCEs make a VSPT considering all candidates of primary and secondary paths. Blocking probability is further decreased since all possible candidates are located, and the sum of primary and secondary path cost is reduced by choosing the pair with minimum cost among all path pairs. Numerical evaluations show that the second and third schemes offer only a few percent reduction in blocking probability and path pair total cost, while the overheads imposed by protocol revision and increase of the amount of calculation and information to be exchanged are large. This suggests that the first scheme, the most basic and simple one, is the best choice.

    14. CHARACTERIZATION OF THE EFFECTS OF INHALED PERCHLOROETHYLENE ON SUSTAINED ATTENTION IN RATS PERFORMING A VISUAL SIGNAL DETECTION TASK

      EPA Science Inventory

      The aliphatic hydrocarbon perchloroethyelene (PCE) has been associated with neurobehavioral dysfunction including reduced attention in humans. The current study sought to assess the effects of inhaled PCE on sustained attention in rats performing a visual signal detection task (S...

    15. Long-term perchloroethylene exposure: a limited meta-analysis of neurobehavorial deficits in occupationally and residentially exposed groups

      EPA Science Inventory

      The literature concerning the neurobehavioral and neurophysiological effects of long-term exposure to perchloroethylene (PERC) in humans was meta-analyzed to provide a quantitative review and synthesis. The useable data base from this literature comprised studies reporting effec...

    16. Aqueous oxidation of trichloroethene (TCE): a kinetic and thermodynamic analysis

      SciTech Connect

      Knauss, K. G., LLNL

      1998-02-28

      An empirical kinetic rate law was determined for the aqueous oxidation of trichloroethene (TCE). By measuring both the rate of disappearance of TCE and the rate of appearance of carbon dioxide and chloride ion, mass balances were monitored to confirm that `mineralization` was the ultimate reaction. Dilute buffer solutions were used to fix pH and stoichiometrically sufficient amounts of dissolved oxygen were used to make the reactions zero-order in oxygen. Using standard chemical kinetic methods, two orders of magnitude were spanned in initial TCE concentration and used in the resulting double-log plot vs. initial rate (regressed using both linear and polynomial fits) to determine the rate constant and `true` reaction order (i.e., with respect to;concentration, not time). By determining rate constants over the temperature interval 343-373K, an Arrhenius activation energy was determined for the reaction. A study was made of the potential effect of buffer ligand concentration and type (phosphate, borate, acetate, carbonate, sulfate), ionic strength, specific electrolytes, and pH on the rate of TCE. The aqueous oxidation reaction rate was found to be pH dependent over the pH range pH 2 to pH 1O and strongly inhibited by high dissolved bromide concentration. The equilibrium aqueous solubilities of TCE was determined by making reversed measurements from 294-390K. Together with the kinetic rate law, the thermodynamic data are required to develop in situ thermal remedial techniques for TCE and to model the reactive transport behavior of TCE in the subsurface.

    17. Genome sequence of the PCE-dechlorinating bacterium Dehalococcoides ethenogenes.

      PubMed

      Seshadri, Rekha; Adrian, Lorenz; Fouts, Derrick E; Eisen, Jonathan A; Phillippy, Adam M; Methe, Barbara A; Ward, Naomi L; Nelson, William C; Deboy, Robert T; Khouri, Hoda M; Kolonay, James F; Dodson, Robert J; Daugherty, Sean C; Brinkac, Lauren M; Sullivan, Steven A; Madupu, Ramana; Nelson, Karen E; Kang, Katherine H; Impraim, Marjorie; Tran, Kevin; Robinson, Jeffrey M; Forberger, Heather A; Fraser, Claire M; Zinder, Stephen H; Heidelberg, John F

      2005-01-01

      Dehalococcoides ethenogenes is the only bacterium known to reductively dechlorinate the groundwater pollutants, tetrachloroethene (PCE) and trichloroethene, to ethene. Its 1,469,720-base pair chromosome contains large dynamic duplicated regions and integrated elements. Genes encoding 17 putative reductive dehalogenases, nearly all of which were adjacent to genes for transcription regulators, and five hydrogenase complexes were identified. These findings, plus a limited repertoire of other metabolic modes, indicate that D. ethenogenes is highly evolved to utilize halogenated organic compounds and H2. Diversification of reductive dehalogenase functions appears to have been mediated by recent genetic exchange and amplification. Genome analysis provides insights into the organism's complex nutrient requirements and suggests that an ancestor was a nitrogen-fixing autotroph. PMID:15637277

    18. Drip Irrigation Aided Phytoremediation for Removal of TCE from Groundwater

      SciTech Connect

      Wilde, E.W.

      2003-04-24

      Groundwater in D-Area at the Savannah River Site (SRS) is contaminated with trichloroethylene (TCE) and by-products resulting from discharges of this organic solvent during past disposal practices. This contaminated groundwater occurs primarily at depths of 9 meters to 15 meters below ground surface, well below the depths that are typically penetrated by plant roots. The process investigated in this study involved pumping water from the contaminated aquifer and discharging the water into overlying test plots two inches below the surface using drip irrigation. The field treatability study was conducted from 8/31/00 to 4/18/02 using six 0.08 hectare test plots, two each containing pines, cottonwoods, and no vegetation (controls). The primary objective was to determine the overall effectiveness of the process for TCE removal and to determine the principal biotic and abiotic pathways for its removal. Results demonstrated that the process provides a viable method to remove TCE-contaminated groundwater. The data clearly showed that the presence of trees reduced volatilization of TCE from the drip irrigation system to the atmosphere. Influent groundwater TCE concentrations averaging 89 mg/L were reduced to non-detectable levels (less than 5 mg/L) within the upper two feet of soil (rhizosphere).

    19. EVALUATION OF GEOPHYSICAL METHODS FOR THE DETECTION OF SUBSURFACE TETRACHLOROETHYLENE (PCE) IN CONTROLLED SPILL EXPERIMENTS

      EPA Science Inventory

      Tetrachloroethylene (PCE), typically used as a dry cleaning solvent, is a predominant contaminant in the subsurface at Superfund Sites. PCE is a dense non-aqueous phase liquid (DNAPL) that migrates downward into the earth, leaving behind areas of residual saturation and free prod...

  1. Widespread PCE Contamination: Characterization and Source Investigation to Protect Municipal Wells

    NASA Astrophysics Data System (ADS)

    Kropf, C. A.; Benedict, J.; Berg, J. H.

    2003-12-01

    Fifteen years of groundwater quality monitoring of municipal wells in Reno, Nevada have shown increasing levels of PCE (tetrachloroethylene) beyond the U.S. EPA MCL of 5 ug/L. Eleven of the 28 municipal wells have detectable levels of PCE, with five of those wells requiring wellhead treatment. The Central Truckee Meadows Remediation District (CTMRD) was created to provide wellhead treatment of PCE, and evaluate, characterize, and remediate (if possible) the PCE-contaminated groundwater. The CTMRD's first tasks of wellhead treatment, plume characterization, remediation plan development, and source zone identification has been completed. The CTMRD recently completed investigations into the presence of PCE in sanitary sewer systems and their potential as pathways for contaminant migration throughout the Reno/Sparks metropolitan area. The first phase of the sewer investigation considered the possibility that PCE resides in the sanitary sewer system and that it may be actively discharged to the sewer system as well. Results of this investigation revealed that nine sub-regions contained maximum PCE concentrations of that exceeded 100 ug/L, 20 times the U.S. EPA MCL of 5 ug/L. Eight of these nine subregions were located downgradient from active dry-cleaning facilities. One of the sampling locations had a maximum PCE concentration greater than 36,000 ug/L over a 24-hour period. The second phase of the sewer investigation explored for the sanitary sewer system to allow PCE to act as a conduit for contaminant migration. A phased approach was employed to investigate the sewer line leakage and resultant soil and groundwater impact. The investigation found that groundwater beneath most of the targeted sewer line reaches was contaminated. In particular, PCE was detected in 88% of all passive soil gas samples, 71% of all active soil gas samples, 23% of all soil samples, and 73% of all groundwater samples.

  2. Methanotrophs for biological pollution control: TCE removal and nutrient removal with the expanded bed. Annual report, January 1, 1991-December 31, 1992

    SciTech Connect

    Jewell, W.J.; Carter, S.R.; Fennell, D.E.; Hicks, E.E.; Nelson, Y.M.

    1992-12-01

    This project had two separate goals; the development of an innovative high biomass attached microbial film reactor for biodegrading chlorinated ethenes and the removal of macronutrients, nitrogen and phosphorus, from wastewaters. The project was initiated in 1987 to identify new approaches to treat PCE and TCE and their by-products in innovative biological systems at the Department of Agricultural and Biological Engineering at Cornell University. This project was sponsored by the Gas Research Insitute and was part of a national effort to identify new and more cost-effective technologies to purify groundwater and other wastewaters. This is the final report in this four-year effort and covers the last two years of activity.

  3. Coupling Surfactant Flushing and Bioaugmentation for PCE-DNAPL Source Zone Treatment

    NASA Astrophysics Data System (ADS)

    Cápiro, N. L.; Granbery, E. K.; Amos, B. K.; Löffler, F. E.; Pennell, K. D.

    2008-12-01

    Enhanced solubilization flushing using a biodegradable surfactant (Tween 80) was combined with bioaugmentation to initiate microbial reductive dechlorination and detoxify residual tetrachloroethene (PCE)- dense nonaqueous phase liquid (DNAPL). Dechlorination activity, spatial distribution of Dehalococcoides spp., and down-gradient plume development were monitored in a 2-D aquifer cell equipped with eighteen sampling ports. Saturation distributions of the PCE-DNAPL source zone were quantified using a light transmission system to determine the ganglia-to-pool (GTP) volume ratio, which was approximately 1.5 (i.e., 60% ganglia and 40% pools) prior to surfactant flushing. Flushing with three pore volumes (PVs) of 4% (w/w) Tween 80 solution recovered approximately 55% of the original PCE mass and reduced PCE effluent concentration from saturation (200 mg/L) to less than 50 mg/L. Following the introduction of reduced basal salts medium amended with 10 mM lactate, nine side ports located upstream and within the initial PCE- DNAPL source zone were augmented with Bio-Dechlor INOCULUM (BDI), a PCE-to-ethene dechlorinating consortium. Flux-averaged measurements of aqueous effluent samples revealed the conversion of PCE to cis-dichloroethene (DCE) with minimal lag time (7 days, approx. 1 PV), and vinyl chloride and ethene were detected within 10 PVs after bioaugmentation. Quantitative real-time PCR (qPCR) targeting Dehalococcoides spp. demonstrated growth once aqueous PCE concentrations decreased below inhibitory levels (~540 mM), with significant growth (2 to 4-orders of magnitude) near the remaining source zone. These results demonstrate the successful colonization of a pool-dominated (NAPL saturation >0.13) PCE- DNAPL source zone by a dechlorinating consortium following partial mass removal, and the potential for locally bioenhanced DNAPL dissolution.

  4. Impact of FeS Mineralogy on TCE Degradation

    EPA Science Inventory

    Iron- and sulfate-reducing conditions are often encountered in permeable reactive barrier (PRB) systems that are constructed to remove TCE from groundwater, which usually leads to the accumulation of FeS mineral phases in the matrix of the PRB. Poorly crystalline mackinawite (Fe...

  5. The Impact of FeS Mineralogy on TCE Degradation

    EPA Science Inventory

    Iron- and sulfate-reducing conditions are often encountered in permeable reactive barrier (PRB) systems that are constructed to remove TCE from groundwater, which usually leads to the accumulation of FeS mineral phases in the matrix of the PRB. Poorly crystalline mackinawite (Fe...

  6. FRACTIONATION OF STABLE CARBON ISOTOPES DURING ABIOTIC TRANSFORMATION OF TCE

    EPA Science Inventory

    At a Superfund Site in Minnesota, ground water is contaminated with trichloroethylene (TCE) with the contaminant plume stretching over five miles long. The ground water is iron and manganese reducing, and the complete absence of dichloroethylene, vinyl chloride, and ethene in th...

  7. In Situ Dechlorination of TCE During Aquifer Heating

    SciTech Connect

    Truex, Michael J.; Powell, Thomas; Lynch, Kira P.

    2007-04-01

    Laboratory and field efforts were undertaken to examine trichloroethene (TCE) dechlorination as a function of temperature as an aquifer is heated to temperatures approaching boiling. Experiments were conducted using sediment samples during electrical resistance heating (ERH) treatment at the Fort Lewis East Gate Disposal Yard, which contains non-aqueous phase TCE and hydrocarbon contamination. Laboratory microcosms with these sediments showed TCE dechlorination at 70oC with measured products of acetylene, ethene, and ethane, indicating an abiotic component of the degradation. In contrast, TCE was dechlorinated to cis-1,2-dichloroethene in experiments at 10oC, likely by biological reductive dechlorination. The observed products at 70oC suggest dechlorination catalyzed by reduced sediment iron. Indications of in situ dechlorination were observed in periodic groundwater samples collected during field-scale electrical resistance heating from an average ambient temperature of about 19oC to near boiling. Dechlorination indicators included an increase in chloride concentration at the onset of heating and observation of acetylene, ethene, and methane at elevated temperatures. The data collected in this study suggest that dechlorination can occur during ERH. The overall cost-effectiveness of ERH may be enhanced by fortuitous in situ dechlorination and, potentially, can be further enhanced by specifically designing and operating ERH to maximize in situ dechlorination.

  8. TCE TRANSPORT AND DEGRADATION IN SOIL USING ELECTROOSMOSIS

    EPA Science Inventory

    Laboratory experiments were used to characterize the transport and chemical transformation of TCE in undisturbed soil cores. Electroosmotic fluid flow was vertically downwards from anode to cathode. A voltage of 1.4 V/cm was applied to the soil for 4 weeks. More than 95% of the T...

  9. Cometabolic Degradation of TCE Vapors in a Foamed Emulsion

    E-print Network

    Cometabolic Degradation of TCE Vapors in a Foamed Emulsion Bioreactor E U N S U N G K A N A N D M)vaporsinanovelgas-phasebioreactorcalledthefoamed emulsion bioreactor (FEBR) was demonstrated. Toluene vapors were used as the primary growth substrate-phase bioreactor called the foamed emulsion bioreactor (FEBR) was developed (20). The FEBR consists of an emulsion

  10. 77 FR 20695 - Tax Counseling for the Elderly (TCE) Program Availability of Application Packages

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-05

    ...TREASURY Internal Revenue Service Tax Counseling for the Elderly (TCE) Program Availability...Application Packages for the 2013 Tax Counseling for the Elderly (TCE) Program. DATES...application package to the IRS for the Tax Counseling for the Elderly (TCE) Program is...

  11. 76 FR 30243 - Tax Counseling for the Elderly (TCE) Program Availability of Application Packages

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

    ...TREASURY Internal Revenue Service Tax Counseling for the Elderly (TCE) Program Availability...Application Packages for the 2012 Tax Counseling for the Elderly (TCE) Program. DATES...package to the IRS for the 2012 Tax Counseling for the Elderly (TCE) Program is...

  12. 75 FR 25319 - Tax Counseling for the Elderly (TCE) Program Availability of Application Packages; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-07

    ...TREASURY Internal Revenue Service Tax Counseling for the Elderly (TCE) Program Availability...a correction to a notice of the Tax Counseling for the Elderly (TCE) Program Availability...application packages for the 2011 Tax Counseling for the Elderly (TCE) Program....

  13. 78 FR 17777 - Tax Counseling for the Elderly (TCE) Program Availability of Application Packages

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-22

    ...TREASURY Internal Revenue Service Tax Counseling for the Elderly (TCE) Program Availability...Application Packages for the 2014 Tax Counseling for the Elderly (TCE) Program. DATES...application package to the IRS for the Tax Counseling for the Elderly (TCE) Program is...

  14. 75 FR 22437 - Tax Counseling for the Elderly (TCE) Program Availability of Application Packages

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-28

    ...TREASURY Internal Revenue Service Tax Counseling for the Elderly (TCE) Program Availability...Application Packages for the 2011 Tax Counseling for the Elderly (TCE) Program. DATES...package to the IRS for the 2011 Tax Counseling for the Elderly (TCE) Program is...

  15. Socioeconomic disparities in indoor air, breath, and blood perchloroethylene level among adult and child residents of buildings with or without a dry cleaner.

    PubMed

    Storm, Jan E; Mazor, Kimberly A; Shost, Stephen J; Serle, Janet; Aldous, Kenneth M; Blount, Benjamin C

    2013-04-01

    In many cities, dry cleaners using perchloroethylene are frequently located in multifamily residential buildings and often cause elevated indoor air levels of perchloroethylene throughout the building. To assess individual perchloroethylene exposures associated with co-located dry cleaners, we measured perchloroethylene in residential indoor air, and in blood and breath of adults and children residing in buildings with a dry cleaner as part of the New York City (NYC) Perc Project. We also measured perchloroethylene in indoor air, and in blood and breath of residents of buildings without a dry cleaner for comparison. Here, we evaluate whether an environmental disparity in perchloroethylene exposures is present. Study participants are stratified by residential building type (dry cleaner or reference) and socioeconomic characteristics (race/ethnicity and income); measures of perchloroethylene exposure are examined; and, the influence of stratified variables and other factors on perchloroethylene exposure is assessed using multivariate regression. All measures of perchloroethylene exposure for residents of buildings with a dry cleaner indicated a socioeconomic disparity. Mean indoor air perchloroethylene levels were about five times higher in minority (82.5 ug/m(3)) than in non-minority (16.5 ug/m(3)) households, and about six times higher in low-income (105.5 ug/m(3)) than in high income (17.8 ug/m(3)) households. Mean blood perchloroethylene levels in minority children (0.27 ng/mL) and adults (0.46 ng/mL) were about two and three times higher than in non-minority children (0.12 ng/mL) and adults (0.15 ng/mL), respectively. Mean blood perchloroethylene levels in low income children (0.34 ng/mL) and adults (0.62 ng/mL) were about three and four times higher than in high income children (0.11 ng/mL) and adults (0.14 ng/mL), respectively. A less marked socioeconomic disparity was observed in perchloroethylene breath levels with minority and low income residents having slightly higher levels than non-minority and high income residents. Multivariate regression affirmed that indoor air perchloroethylene level in dry cleaner buildings was the single most important factor determining perchloroethylene in blood and breath. Neither age, gender, nor socioeconomic status significantly influenced perchloroethylene levels in breath or blood. We previously reported that increased indoor air, breath, and blood perchloroethylene levels among NYC Perc Project child participants were associated with an increased risk for slightly altered vision. Thus, the disproportionately elevated perchloroethylene exposures of minority and low-income child residents of buildings with a dry cleaner shown here constitutes an environmental exposure disparity with potential public health consequences. Among residents of buildings without a dry cleaner, we observed some small increases in perchloroethylene breath and blood levels among non-minority or high income residents compared to minority or low income residents. These differences were not attributable to differences in indoor air levels of perchloroethylene which did not differ across socioeconomic categories, but appear to be associated with more frequent exposures dry cleaned garments. PMID:23453848

  16. A mass balance study of the phytoremediation of perchloroethylene-contaminated groundwater

    E-print Network

    Doty, Sharon Lafferty

    in the effluent water or volatilized into the air. These results suggest that phytoremediation can be an effective of the most common environmental pollutants found at National Priority List and Superfund sites (United States on a planted test bed with PCE-contaminated water demonstrated VOC mass reduction of 99% and complete

  17. Expert system methodology for evaluating reductive dechlorination at TCE sites

    SciTech Connect

    Stiber, N.A.; Pantazidou, M.; Small, M.J.

    1999-09-01

    An expert knowledge site-screening methodology has been developed to evaluate naturally occurring reductive dechlorination as a remedial option for sites with TCE-contaminated groundwater. This methodology combines a causative model for the reductive dechlorination of TCE and expert knowledge within a Bayesian Belief Network. The knowledge base for this expert system was obtained from 22 experts via an expert elicitation protocol The resulting expert system can be used to aid environmental decision making by evaluating the adequacy of reductive dechlorination at TCE-contaminated sites. Comparisons between this expert system and a commonly used screening tool show that this expert system reproduces predictive models that may better discriminate between locations that were sampled. The 22 elicitations revealed different beliefs and assumptions among experts about the biochemical processes involved in reductive dechlorination. The decision-making value of some types of evidence is a matter of dispute; however, findings about biodegradation daughter and/or end products have high decision-making value for all of the experts. The methodology demonstrated herein can provide insights for other environmental decision-making challenges.

  18. Enhanced Reductive Dechlorination of TCE in a Basalt Aquifer

    SciTech Connect

    K. S. Sorenson; L. N. Peterson; R. Ely

    1999-04-01

    A field evaluation of enhanced reductive dechlorination of trichloroethene (TCE) in groundwater has been in progress since November 1998 to determine whether in situ biodegradation can be significantly enhanced through the addition of an electron donor (lactate). An in situ treatment cell was established in the residual source area of a large TCE plume in a fractured basalt aquifer utilizing continuous ground water extraction approximately 150 meters downgradient of the injection location. After a 1-month tracer test and baseline sampling period, the pulsed injection of lactate was begun. Ground water samples were collected from 11 sampling points on a biweekly basis and in situ water quality parameters were recorded every 4 hours at two locations. Within 2 weeks after the initial lactate injection, dissolved oxygen and redox potential were observed to decrease substantially at all sampling locations within 40 m of the injection well. Decreases in nitrate and sulfate concentrations were also observed. Both quantitative in situ rate estimation methods and qualitative measures such as changes in redox conditions, decreases in chlorine number, and changes in biomass indicator parameters are being used throughout the test to evaluate the extent to which biodegradation of TCE is enhanced.

  19. Enhanced Reductive Dechlorination of TCE in a Basalt Aquifer

    SciTech Connect

    Sorenson, Kent Soren; Peterson, Lance Nutting; Ely, R. L.

    1999-04-01

    A field evaluation of enhanced reductive dechlorination of trichloroethene (TCE) in ground water has been in progress since November 1998 to determine whether in situ biodegradation can be significantly enhanced through the addition of an electron donor (lactate). An in situ treatment cell was established in the residual source area of a large TCE plume in a fractured basalt aquifer utilizing continuous ground water extraction approximately 150 meters downgradient of the injection location. After a 1-month tracer test and baseline sampling period, the pulsed injection of lactate was begun. Ground water samples were collected from 11 sampling points on a biweekly basis and in situ water quality parameters were recorded every 4 hours at two locations. Within 2 weeks after the initial lactate injection, dissolved oxygen and redox potential were observed to decrease substantially at all sampling locations within 40 m of the injection well. Decreases in nitrate and sulfate concentrations were also observed. Both quantitative in situ rate estimation methods and qualitative measures such as changes in redox conditions, decreases in chlorine number, and changes in biomass indicator parameters are being used throughout the test to evaluate the extent to which biodegradation of TCE is enhanced.

  20. A Planet Hunters Search of the Kepler TCE Inventory

    NASA Astrophysics Data System (ADS)

    Schwamb, Meg; Lintott, Chris; Fischer, Debra; Smith, Arfon; Boyajian, Tabetha; Brewer, John; Giguere, Matt; Lynn, Stuart; Schawinski, Kevin; Simpson, Rob; Wang, Ji

    2013-07-01

    NASA's Kepler spacecraft has spent the past 4 years monitoring ~160,000 stars for the signatures of transiting exoplanets. Planet Hunters (http://www.planethunters.org), part of the Zooniverse (http://www.zooniverse.org) collection of citizen science projects, uses the power of human pattern recognition via the World Wide Web to identify transits in the Kepler public data. We have demonstrated the success of a citizen science approach with the project's discoveries including PH1 b, a transiting circumbinary planet in a four star system., and over 20 previously unknown planet candidates. The Kepler team has released the list of 18,406 potential transit signals or threshold-crossing events (TCEs) identified in Quarters 1-12 (~1000 days) by their automated Transit Planet Search (TPS) algorithm. The majority of these detections found by TPS are triggered by transient events and are not valid planet candidates. To identify planetary candidates from the detected TCEs, a human review of the validation reports, generated by the Kepler pipeline for each TCE, is performed by several Kepler team members. We have undertaken an independent crowd-sourced effort to perform a systematic search of the Kepler Q1-12 TCE list. With the Internet we can obtain multiple assessments of each TCE's data validation report. Planet Hunters volunteers evaluate whether a transit is visible in the Kepler light curve folded on the expected period identified by TPS. We present the first results of this analysis.

  1. Bacteria associated with oak and ash on a TCE-contaminated site: Characterization of isolates with potential to avoid evapotranspiration of TCE

    SciTech Connect

    Weyens, N.; van der Lelie, D.; Taghavi, S.; Barac, T.; Boulet, J.; Artois, T.; Carleer, R.; Vangronsveld, J.

    2009-11-01

    Along transects under a mixed woodland of English Oak (Quercus robur) and Common Ash (Fraxinus excelsior) growing on a trichloroethylene (TCE)-contaminated groundwater plume, sharp decreases in TCE concentrations were observed, while transects outside the planted area did not show this remarkable decrease. This suggested a possibly active role of the trees and their associated bacteria in the remediation process. Therefore, the cultivable bacterial communities associated with both tree species growing on this TCE-contaminated groundwater plume were investigated in order to assess the possibilities and practical aspects of using these common native tree species and their associated bacteria for phytoremediation. In this study, only the cultivable bacteria were characterized because the final aim was to isolate TCE-degrading, heavy metal resistant bacteria that might be used as traceable inocula to enhance bioremediation. Cultivable bacteria isolated from bulk soil, rhizosphere, root, stem, and leaf were genotypically characterized by amplified rDNA restriction analysis (ARDRA) of their 16S rRNA gene and identified by 16S rRNA gene sequencing. Bacteria that displayed distinct ARDRA patterns were screened for heavy metal resistance, as well as TCE tolerance and degradation, as preparation for possible future in situ inoculation experiments. Furthermore, in situ evapotranspiration measurements were performed to investigate if the degradation capacity of the associated bacteria is enough to prevent TCE evapotranspiration to the air. Between both tree species, the associated populations of cultivable bacteria clearly differed in composition. In English Oak, more species-specific, most likely obligate endophytes were found. The majority of the isolated bacteria showed increased tolerance to TCE, and TCE degradation capacity was observed in some of the strains. However, in situ evapotranspiration measurements revealed that a significant amount of TCE and its metabolites was evaporating through the leaves to the atmosphere. The characterization of the isolates obtained in this study shows that the bacterial community associated with Oak and Ash on a TCE-contaminated site, was strongly enriched with TCE-tolerant strains. However, this was not sufficient to degrade all TCE before it reaches the leaves. A possible strategy to overcome this evapotranspiration to the atmosphere is to enrich the plant-associated TCE-degrading bacteria by in situ inoculation with endophytic strains capable of degrading TCE.

  2. Abiotic dechlorination in rock matrices impacted by long-term exposure to TCE.

    PubMed

    Schaefer, Charles E; Towne, Rachael M; Lippincott, David R; Lacombe, Pierre J; Bishop, Michael E; Dong, Hailiang

    2015-01-01

    Field and laboratory tests were performed to evaluate the abiotic reaction of trichloroethene (TCE) in sedimentary rock matrices. Hydraulically conductive fractures, and the rock directly adjacent to the hydraulically conductive fractures, within a historically contaminated TCE bedrock aquifer were used as the basis for this study. These results were compared to previous work using rock that had not been exposed to TCE (Schaefer et al., 2013) to assess the impact of long-term TCE exposure on the abiotic dechlorination reaction, as the longevity of these reactions after long-term exposure to TCE was hitherto unknown. Results showed that potential abiotic TCE degradation products, including ethane, ethene, and acetylene, were present in the conductive fractures. Using minimally disturbed slices of rock core at and near the fracture faces, laboratory testing on the rocks confirmed that abiotic dechlorination reactions between the rock matrix and TCE were occurring. Abiotic daughter products measured in the laboratory under controlled conditions were consistent with those measured in the conductive fractures, except that propane also was observed as a daughter product. TCE degradation measured in the laboratory was well described by a first order rate constant through the 118-d study. Observed bulk first-order TCE degradation rate constants within the rock matrix were 1.3×10(-8) s(-1). These results clearly show that abiotic dechlorination of TCE is occurring within the rock matrix, despite decades of exposure to TCE. Furthermore, these observed rates of TCE dechlorination are expected to have a substantial impact on TCE migration and uptake/release from rock matrices. PMID:25192648

  3. The use of micropores for fine bubble creation in the removal of PCE in groundwater

    SciTech Connect

    Kerfoot, W.B.; McCulloch, W.; Connors, J.

    1996-12-01

    The use of microporous Spargepoint{reg_sign} to create fine bubbles, which easily penetrate sandy formations to allow fluid flow, has unexpected benefits when used with multiple gas systems. Microfine bubbles accelerate the transfer rate of PCE from aqueous to gaseous state. The bubble rise transfers the PCE to the vadose zone. The ten-fold difference in surface-to-volume ratio of Spargepoint{reg_sign} microbubbles compared to bubbles from well screens results in a three-fold improvement in transfer rates. To block the gaseous state from reverting to surface dissolved state in the vadose (unsaturated) zone, a microprocessor system shuttles an oxidizing gas through the vadose zone to chemically degrade the transported PCE. Destruction of the PCE and vacuum extraction of gaseous byproducts eliminates reflux of the contaminant under rainfall conditions in the unsaturated zone. Use of a 50 CFM sparge system at the Crossroads Mall site in Carson City, Nevada resulted in extremely rapid removal of PCE.

  4. Field and laboratory evaluation of a diffusive emitter for semipassive release of PCE to an aquifer

    SciTech Connect

    Arildskov, N.P.; Devlin, J.F.

    2000-02-01

    In controlled field experiments or model aquifers, it is sometimes desirable to introduce solutes below the water table without perturbing the flow system. Diffusive emitters offer a means of achieving that goal. In this study, two laboratory experiments were conducted to evaluate nylon tubing as a diffusive emitter for tetrachloroethene (PCE). The initial approach was to pump a saturated aqueous PCE solution through a piece of nylon tubing immersed in a flow-through contractor vessel. Millipore water was pumped through the contractor vessel at a constant rate. Due to PCE diffusion through the nylon, a steady-state concentration in the contractor vessel eventually developed. The process was well described by a computer model that accounted for retarded diffusion through the nylon. In a second experiment, pieces of nylon tubing were exposed to a relatively low concentration of PCE in water for 10 days in gently rotated hypovials. With the aid of a second diffusion model, the bulk diffusion coefficient was obtained from the concentration history of the solution. With the different experimental conditions taken into account, there was reasonably good agreement between the bulk diffusion coefficients in the two experiments. The results were used in the field design of a semipassive release system. Evaluation of this system showed a lower than expected steady-state concentration of PCE inside the releasing wells. The difference is likely due to lower temperature, variable PCE concentrations in the nylon tubing, and nonideal mixing in the wells. The work has shown that laboratory derived diffusion coefficients for polymeric materials are likely to be larger than, but within an order of magnitude of, the effective diffusion coefficients exhibited by emitters in the field. Nevertheless, with temperature corrections taken into account and proper well development, these values could be used to design emitters that would suit most practical applications.

  5. Steam and air co-injection in removing residual TCE in unsaturated layered sandy porous media.

    PubMed

    Peng, Sheng; Wang, Ning; Chen, Jiajun

    2013-10-01

    Steam and air co-injection is a promising technique for volatile and semi-volatile organic contaminant remediation in heterogeneous porous media. In this study, removal of trichloroethene (TCE) with steam-air co-injection was investigated through a series of 2D sandbox experiments with different layered sand structures, and through numerical simulations. The results show that a layered structure with coarse sand, in which steam and air convection are relatively rapid, resulted in a higher removal rate and a larger removal ratio than those observed in an experiment using finer sand; however, the difference was not significant, and the removal ratios from three experiments ranged from 85% to 94%. Slight downward movement of TCE was observed for Experiment 1 (TCE initially in a fine sand zone encased in a coarse sand), while no such movement was observed for Experiment 2 (TCE initially in two fine sand layers encased in a coarse sand) or 3 (TCE initially in a silty sand zone encased in a coarse sand). Simulations show accumulation of TCE at the interface of the layered sands, which indicates a capillary barrier effect in restraining the downward movement of TCE. This effect is illustrated further by a numerical experiment with homogeneous coarse sand, in which continuous downward TCE movement to the bottom of the sandbox was simulated. Another numerical experiment with higher water saturation was also conducted. The results illustrate a complicated influence of water saturation on TCE removal in a layered sand structure. PMID:23962760

  6. Adult neuropsychological performance following prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water.

    PubMed

    Janulewicz, Patricia A; White, Roberta F; Martin, Brett M; Winter, Michael R; Weinberg, Janice M; Vieira, Veronica; Aschengrau, Ann

    2012-01-01

    This population-based retrospective cohort study examined adult performance on a battery of neuropsychological tests in relation to prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using pipe network information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and a Geographic Information System (GIS). Results of crude and multivariate analyses among 35 exposed and 28 unexposed subjects showed no association between prenatal and early postnatal exposure and decrements on tests that assess abilities in the domains of omnibus intelligence, academic achievement or language. The results were suggestive of an association between prenatal and early postnatal PCE exposure and diminished performance on tests that assessed abilities in the domains of visuospatial functioning, learning and memory, motor, attention and mood. Because the sample size was small, most findings were not statistically significant. Future studies with larger sample sizes should be conducted to further define the neuropsychological consequences of early developmental PCE exposure. PMID:22522125

  7. Adult Neuropsychological Performance Following Prenatal and Early Postnatal Exposure to Tetrachloroethylene (PCE)-contaminated Drinking Water

    PubMed Central

    Janulewicz, Patricia A; White, Roberta F; Martin, Brett M; Winter, Michael R; Weinberg, Janice M; Vieira, Veronica; Aschengrau, Ann

    2012-01-01

    This population-based retrospective cohort study examined adult performance on a battery of neuropsychological tests in relation to prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using pipe network information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and a Geographic Information System (GIS). Results of crude and multivariate analyses among 35 exposed and 28 unexposed subjects showed no association between prenatal and early postnatal exposure and decrements on tests that assess abilities in the domains of omnibus intelligence, academic achievement or language. The results were suggestive of an association between prenatal and early postnatal PCE exposure and diminished performance on tests that assessed abilities in the domains of visuospatial functioning, learning and memory, motor, attention and mood. Because the sample size was small, most findings were not statistically significant. Future studies with larger sample sizes should be conducted to further define the neuropsychological consequences of early developmental PCE exposure. PMID:22522125

  8. FIELD MEASUREMENT OF VAPOR INTRUSION RATES AT A PCE SITE (ABSTRACT ONLY)

    EPA Science Inventory

    A field study was performed to evaluate vapor intrusion (VI) of tetrachloroethylene (PCE) and other chlorinated solvents at a commercial retail site in Dallas, TX. The building is approximately 40 years old and once housed a dry cleaning operation. Results from an initial site ch...

  9. Cognitive ATI Research: A Simulated Laboratory Environment in (PCE-)Prolog.

    ERIC Educational Resources Information Center

    Kamsteeg, Paul A.; Bierman, Dick J.

    A study of 228 undergraduate psychology students examined the effectiveness of a prototype of "heatlab," a laboratory simulation written in PCE-PROLOG, intended for remedying misconceptions of the concepts "heat" and "temperature." The effect of varying the amount of structure on students' understanding and the possibility of an interaction…

  10. Sewer Gas: An Indoor Air Source of PCE to Consider During Vapor Intrusion Investigations

    PubMed Central

    Pennell, Kelly G.; Scammell, Madeleine Kangsen; McClean, Michael D.; Ames, Jennifer; Weldon, Brittany; Friguglietti, Leigh; Suuberg, Eric M.; Shen, Rui; Indeglia, Paul A.; Heiger-Bernays, Wendy J.

    2013-01-01

    The United States Environmental Protection Agency (USEPA) is finalizing its vapor intrusion guidelines. One of the important issues related to vapor intrusion is background concentrations of volatile organic chemicals (VOCs) in indoor air, typically attributed to consumer products and building materials. Background concentrations can exist even in the absence of vapor intrusion and are an important consideration when conducting site assessments. In addition, the development of accurate conceptual models that depict pathways for vapor entry into buildings is important during vapor intrusion site assessments. Sewer gas, either as a contributor to background concentrations or as part of the site conceptual model, is not routinely evaluated during vapor intrusion site assessments. The research described herein identifies an instance where vapors emanating directly from a sanitary sewer pipe within a residence were determined to be a source of tetrachloroethylene (PCE) detected in indoor air. Concentrations of PCE in the bathroom range from 2.1 to 190 ug/m3 and exceed typical indoor air concentrations by orders of magnitude resulting in human health risk classified as an “Imminent Hazard” condition. The results suggest that infiltration of sewer gas resulted in PCE concentrations in indoor air that were nearly two-orders of magnitude higher as compared to when infiltration of sewer gas was not known to be occurring. This previously understudied pathway whereby sewers serve as sources of PCE (and potentially other VOC) vapors is highlighted. Implications for vapor intrusion investigations are also discussed. PMID:23950637

  11. The Impact of Composition on the Physical Properties and Evaporative Mass Transfer of a PCE-Diesel Immiscible Liquid

    PubMed Central

    Carroll, Kenneth C.; Taylor, Renee; Gray, Evan; Brusseau, Mark L.

    2010-01-01

    The impact of immiscible-liquid composition on mass transfer between immiscible liquid and vapor was evaluated for a complex mixture of chlorinated solvents and petroleum hydrocarbons. A mixture of PCE (tetrachloroethene) and diesel was discovered at a site in Tucson, Arizona. Partitioning of PCE into a previously spilled diesel free product has been observed, with resultant concentrations of PCE above 15% by weight. The density, viscosity, surface tension, and interfacial tension were measured for PCE-diesel mixtures with PCE fractions from 7 to 32%, and the results indicated that immiscible-liquid composition did impact the physical properties of the PCE-diesel mixture. Comparison of gas and aqueous phase partitioning results to predictions based on Raoult's Law indicated that the immiscible liquid behaved essentially as an ideal mixture. Flow-cell experiments were conducted to characterize PCE removal from the PCE-diesel mixture via vapor extraction. The effluent concentrations for the experiment conducted with free-phase immiscible liquid were comparable to equilibrium values. Conversely, they were significantly lower for the experiment wherein a residual saturation of immiscible liquid was distributed within sand. These results suggest that evaporation for the latter experiment was constrained by rate-limited mass transfer, which was attributed to dilution effects associated with a nonuniform immiscible-liquid distribution. PMID:18926630

  12. Biodegradation of high concentrations of tetrachloroethene in a continuous flow column system

    SciTech Connect

    Isalou, M; Sleep, B.E.; Liss, S.N.

    1998-11-15

    A long-term (2.5 years) study of the anaerobic biodegradation of high concentrations of perchloroethylene (PCE) was carried out in a continuously operated laboratory column filled with sand which was inoculated with biomass from an anaerobic digester. Concentrations of PCE fed to the column were increased from 12 {micro}M to over 600 {micro}M over 21 months, with methanol added as electron donor. Vinyl chloride (VC) was the terminal product of PCE dechlorination for the first 21 months at which point significant conversion of VC to ethylene (ETH) was detected. The onset of ETH production coincided with acetogenesis becoming the primary pathway for methanol metabolism. ETH production occurred in the column in the presence of PCE and TCE. Varying methanol:PCE molar ratios from 1.4 to 7.5 had little effect on the transformation of PCE and TCE to VC. The degradation of VC to ETH was much more sensitive, and VC accumulated when the methanol:PCE molar ratio dropped below 5.0. Withdrawal of PCE from the system for a 5 month period and maintenance of the column on methanol alone did not result in the loss of PCE degradation capability of the consortium.

  13. Functional Analysis of Esterase TCE2 Gene from Tetranychus cinnabarinus (Boisduval) involved in Acaricide Resistance.

    PubMed

    Shi, Li; Wei, Peng; Wang, Xiangzun; Shen, Guangmao; Zhang, Jiao; Xiao, Wei; Xu, Zhifeng; Xu, Qiang; He, Lin

    2016-01-01

    The carmine spider mite, Tetranychus cinnabarinus is an important pest of crops and vegetables worldwide, and it has the ability to develop resistance against acaricides rapidly. Our previous study identified an esterase gene (designated TCE2) over-expressed in resistant mites. To investigate this gene's function in resistance, the expression levels of TCE2 in susceptible, abamectin-, fenpropathrin-, and cyflumetofen-resistant strains were knocked down (65.02%, 63.14%, 57.82%, and 63.99%, respectively) via RNA interference. The bioassay data showed that the resistant levels to three acaricides were significantly decreased after the down-regulation of TCE2, indicating a correlation between the expression of TCE2 and the acaricide-resistance in T. cinnabarinus. TCE2 gene was then re-engineered for heterologous expression in Escherichia coli. The recombinant TCE2 exhibited ?-naphthyl acetate activity (483.3?±?71.8?nmol/mg pro. min(-1)), and the activity of this enzyme could be inhibited by abamectin, fenpropathrin, and cyflumetofen, respectively. HPLC and GC results showed that 10??g of the recombinant TCE2 could effectively decompose 21.23% fenpropathrin and 49.70% cyflumetofen within 2?hours. This is the first report of a successful heterologous expression of an esterase gene from mites. This study provides direct evidence that TCE2 is a functional gene involved in acaricide resistance in T. cinnabarinus. PMID:26725309

  14. MICROFRACTURE SURFACE GEOCHEMISTRY AND ADHERENT MICROBIAL POPULATION METABOLISM IN TCE-CONTAMINATED COMPETENT BEDROCK

    EPA Science Inventory

    A TCE-contaminated competent bedrock site in Portsmouth, NH was used to determine if a relation existed between microfracture (MF) surface geochemistry and the ecology and metabolic activity of attached microbes relative to terminal electron accepting processes (TEAPs) and TCE bi...

  15. Global Gene Expression of Dehalococcoides Within a Robust Dynamic TCE-Dechlorinating

    E-print Network

    Alvarez-Cohen, Lisa

    ARTICLE Global Gene Expression of Dehalococcoides Within a Robust Dynamic TCE was used to analyze gene expression in a robust long-term trichloroethene (TCE)- degrading microbial through regulation in Dhc. Most Dhc genes were significantly down-regulated at T3, responding to a lack

  16. Use of emulsified vegetable oil to support bioremediation of TCE DNAPL in soil columns

    NASA Astrophysics Data System (ADS)

    Harkness, Mark; Fisher, Angela

    2013-08-01

    The interaction between emulsified vegetable oil (EVO) and trichloroethylene (TCE) dense non-aqueous phase liquid (DNAPL) was observed using two soil columns and subsequent reductive dechlorination of TCE was monitored over a three year period. Dyed TCE DNAPL (~ 75 g) was emplaced in one column (DNAPL column), while the second was DNAPL-free (plume column). EVO was added to both columns and partitioning of the EVO into the TCE DNAPL was measured and quantified. TCE (1.9 mM) was added to the influent of the plume column to simulate conditions down gradient of a DNAPL source area and the columns were operated independently for more than one year, after which they were connected in series. Initially limited dechlorination of TCE to cDCE was observed in the DNAPL column, while the plume column supported complete reductive dechlorination of TCE to ethene. Upon connection and reamendment of the plume column with EVO, near saturation levels of TCE from the effluent of the DNAPL column were rapidly dechlorinated to c-DCE and VC in the plume column; however, this high rate dechlorination produced hydrochloric acid which overwhelmed the buffering capacity of the system and caused the pH to drop below 6.0. Dechlorination efficiency in the columns subsequently deteriorated, as measured by the chloride production and Dehalococcoides counts, but was restored by adding sodium bicarbonate buffer to the influent groundwater. Robust dechlorination was eventually observed in the DNAPL column, such that the TCE DNAPL was largely removed by the end of the study. Partitioning of the EVO into the DNAPL provided significant operational benefits to the remediation system both in terms of electron donor placement and longevity.

  17. Use of emulsified vegetable oil to support bioremediation of TCE DNAPL in soil columns.

    PubMed

    Harkness, Mark; Fisher, Angela

    2013-08-01

    The interaction between emulsified vegetable oil (EVO) and trichloroethylene (TCE) dense non-aqueous phase liquid (DNAPL) was observed using two soil columns and subsequent reductive dechlorination of TCE was monitored over a three year period. Dyed TCE DNAPL (~75 g) was emplaced in one column (DNAPL column), while the second was DNAPL-free (plume column). EVO was added to both columns and partitioning of the EVO into the TCE DNAPL was measured and quantified. TCE (1.9 mM) was added to the influent of the plume column to simulate conditions down gradient of a DNAPL source area and the columns were operated independently for more than one year, after which they were connected in series. Initially limited dechlorination of TCE to cDCE was observed in the DNAPL column, while the plume column supported complete reductive dechlorination of TCE to ethene. Upon connection and reamendment of the plume column with EVO, near saturation levels of TCE from the effluent of the DNAPL column were rapidly dechlorinated to c-DCE and VC in the plume column; however, this high rate dechlorination produced hydrochloric acid which overwhelmed the buffering capacity of the system and caused the pH to drop below 6.0. Dechlorination efficiency in the columns subsequently deteriorated, as measured by the chloride production and Dehalococcoides counts, but was restored by adding sodium bicarbonate buffer to the influent groundwater. Robust dechlorination was eventually observed in the DNAPL column, such that the TCE DNAPL was largely removed by the end of the study. Partitioning of the EVO into the DNAPL provided significant operational benefits to the remediation system both in terms of electron donor placement and longevity. PMID:23697993

  18. Solubilities of Toluene, Benzene and TCE in High-Biomass Systems

    SciTech Connect

    Barton, John W.; Vodraska, Christopher D; Flanary, Sandie A.; Davison, Brian H

    2008-01-01

    We report measurements of solubility limits for benzene, toluene, and TCE in systems that contain varying levels of biomass up to 0.13 g/mL. The solubility limit increased from 20 to 48 mM when biomass (in the form of yeast) was added to aqueous batch systems containing benzene. The toluene solubility limit increased from 4.9 to greater than 20 mM. For TCE, the solubility increased from 8 mM to more than 1000 mM. Solubility for TCE was most heavily impacted by biomass levels, changing by two orders of magnitude.

  19. Comparison of TCeMA and TDMA for Inter-Satellite Communications using OPNET Simulation

    NASA Technical Reports Server (NTRS)

    Hain, Regina Rosales; Ramanathan, Ram; Bergamo, Marcos; Wallett, Thomas M.

    2003-01-01

    A robust data link protocol, enabling unique physical and MAC layer technologies and sub-network level protocols, is needed in order to take advantage of the full potential of using both TDMA and CDMA in a satellite communication network. A novel MAC layer protocol, TDMA with CDMA-encoding multiple access (TCeMA) integrated with null-steered digital beam-forming spatial multiplexing, is investigated to support flexible spacecraft communications. Abstract models of the TCeMA and TDMA processes are developed in OPNFiT and a comparison of the performances of TCeMA and TDMA in a satellite network simulation are made. TCeMA provides the better connectivity and capacity with respect to TDMA for satellite communication traffic.

  20. UNCERTAINTY ANALYSIS OF TCE USING THE DOSE EXPOSURE ESTIMATING MODEL (DEEM) IN ACSL

    EPA Science Inventory

    The ACSL-based Dose Exposure Estimating Model(DEEM) under development by EPA is used to perform art uncertainty analysis of a physiologically based pharmacokinetic (PSPK) model of trichloroethylene (TCE). This model involves several circulating metabolites such as trichloroacet...

  1. IDENTIFICATION OF CHLOROMETHANE FORMATION PATHS DURING ELECTROCHEMICAL DECHLORINATION OF TCE USING GRAPHITE ELECTRODES

    EPA Science Inventory

    The purpose of this research is to investigate the formation of chloromethane during TCE dechlorination in a mixed electrochemical reactor using graphite electrodes. Chloromethane was the major chlorinated organic compound detected in previous dechlorination experiments. In order...

  2. IDENTIFICATION OF CHLOROMETHANE FROMATION PATHS DURING ELECTROCHEMICAL DECHLORINATION OF TCE USING GRAPHITE ELECTRODES

    EPA Science Inventory

    The purpose of this research is to investigate the formation of chloromethane during TCE dechlorination in a mixed electrochemical reactor using graphite electrodes. Chloromethane was the major chlorinated organic compound detected in previous dechlorination experiments. In order...

  3. In-situ bioremediation of TCE-contaminated groundwater

    SciTech Connect

    Travis, B.J.; Rosenberg, N.D.

    1998-12-31

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). A barrier to wider use of in situ bioremediation technology is that results are often variable and difficult to predict. In situ bioremediation has shown some very notable and well publicized successes, but implementation of the technology is complex. An incomplete understanding of the effects of variable site characteristics and the lack of adequate tools to predict and measure success have made the design, control and validation of bioremediation more empirical than desired. The long-term objective of this project is to improve computational tools used to assess and optimize the expected performance of bioremediation at a site. An important component of the approach is the explicit inclusion of uncertainties and their effect on the end result. The authors have extended their biokinetics model to include microbial competition and predation processes. Predator species can feed on the microbial species that degrade contaminants, and the simulation studies show that species interactions must be considered when designing in situ bioremediation systems. In particular, the results for TCE indicate that protozoan grazing could reduce the amount of biodegradation by about 20%. These studies also indicate that the behavior of barrier systems can become complex due to predator grazing.

  4. Modeling the uptake and transpiration of TCE using phreatophytic trees. Master`s Thesis

    SciTech Connect

    Wise, D.P.

    1997-12-01

    Phytoremediation is a recent addition to the numerous methods used today to remediate ground water contaminants. It is proving more effective and efficient compared to existing remediation techniques. The use of phreatophytes, or water seeking trees, has great potential for phytoremediation. These trees are fast growing, long lived, grow their roots down to the ground water table, transpire large amounts of water, and are proven to actively remove contaminants from the soil horizon. The purpose of this research is to develop quantitative concepts for understanding the dynamics of TCE uptake and transpiration by phreatophytic trees over a short rotation woody crop time frame. This will he done by constructing a system dynamics model of this process and running it over a wide range of conditions. This research will offer managers a tool to simulate long-term uptake and transpiration of TCE at potential sites. The results of this study indicate that TCE is actively removed from the soil horizon by phreatophytic trees and a significant proportion of this TCE is then transpired. Changes in soil horizon parameters, xylem flow rates, and variables in the uptake equation greatly influence TCE uptake rates as well as transpiration. Also, parameters used in equations representing flows in and out of the leaf greatly influence transpiration. Better understanding of these processes is essential for managers to accurately predict the amount of TCE removed and transpired during potential phytoremediation projects.

  5. Endophytic bacteria improve phytoremediation of Ni and TCE co-contamination

    SciTech Connect

    Weyens, N.; van der Lelie, D.; Croes, S.; Dupae, J.; Newman, L.; Carleer, R.; Vangronsveld, J.

    2010-07-01

    The aim of this work was to investigate if engineered endophytes can improve phytoremediation of co-contaminations by organic pollutants and toxic metals. As a model system, yellow lupine was inoculated with the endophyte Burkholderia cepacia VM1468 possessing (a) the pTOM-Bu61 plasmid, coding for constitutive trichloroethylene (TCE) degradation, and (b) the ncc-nre Ni resistance/sequestration system. Plants were exposed to Ni and TCE and (a) Ni and TCE phytotoxicity, (b) TCE degradation and evapotranspiration, and (c) Ni concentrations in the roots and shoots were determined. Inoculation with B. cepacia VM1468 resulted in decreased Ni and TCE phytotoxicity, as measured by 30% increased root biomass and up to 50% decreased activities of enzymes involved in anti-oxidative defence in the roots. In addition, TCE evapotranspiration showed a decreasing trend and a 5 times higher Ni uptake was observed after inoculation. Engineered endophytes can improve phytoremediation of mixed contaminations via enhanced degradation of organic contaminants and improved metal uptake and translocation.

  6. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Technical Reports Server (NTRS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-01-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  7. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Astrophysics Data System (ADS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-03-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  8. [Steam and air co-injection in removing TCE in 2D-sand box].

    PubMed

    Wang, Ning; Peng, Sheng; Chen, Jia-Jun

    2014-07-01

    Steam and air co-injection is a newly developed and promising soil remediation technique for non-aqueous phase liquids (NAPLs) in vadose zone. In this study, in order to investigate the mechanism of the remediation process, trichloroethylene (TCE) removal using steam and air co-injection was carried out in a 2-dimensional sandbox with different layered sand structures. The results showed that co-injection perfectly improved the "tailing" effect compared to soil vapor extraction (SVE), and the remediation process of steam and air co-injection could be divided into SVE stage, steam strengthening stage and heat penetration stage. Removal ratio of the experiment with scattered contaminant area was higher and removal speed was faster. The removal ratios from the two experiments were 93.5% and 88.2%, and the removal periods were 83.9 min and 90.6 min, respectively. Steam strengthened the heat penetration stage. The temperature transition region was wider in the scattered NAPLs distribution experiment, which reduced the accumulation of TCE. Slight downward movement of TCE was observed in the experiment with TCE initially distributed in a fine sand zone. And such downward movement of TCE reduced the TCE removal ratio. PMID:25244869

  9. Microbial community changes associated with a shift from reductive dechlorination of PCE to reductive dechlorination of cis-DCE and VC

    SciTech Connect

    Flynn, S.J.; Loeffler, F.E.; Tiedje, J.M.

    2000-03-15

    Subcultures that reductively dechlorinate cis-dichloroethene (cis-DCE) or vinyl chloride (VC) were derived from three independent enrichments that completely dechlorinated tetrachloroethene (PCE) to ethene in order to study the reductive dechlorination of the lesser chlorinated ethenes. These subcultures completely dechlorinated cis-DCE and VC and could be transferred indefinitely in basal salts minimal medium with H{sub 2} as the electron donor. After 10 transfers (1% V/V) the cis-DCE and VC-dechlorinating subcultures from two of the PCE enrichments failed to dechlorinate PCE, but the subcultures from the third PCE enrichment maintained the ability to dechlorinate PCE. Analysis of the 16S rRNA genes from these enrichments by terminal restriction fragment length polymorphism (T-RFLP) and denaturing gradient gel electrophoresis (DGGE) demonstrated shifts in the community composition of the subcultures that had lost the PCE-dechlorinating activity but not in the subcultures that maintained the PCE-dechlorinating activity. Analysis of the changes in community composition of the different enrichments suggested that at least two populations were responsible for the sequential dechlorination of PCE to ethene in these cultures and that consortia can cooperate in the complete dechlorination of PCE.

  10. In situ, subsurface monitoring of vapor-phase TCE using fiber optics

    SciTech Connect

    Rossabi, J.; Colston, B. Jr.; Brown, S.; Milanovich, F.; Lee, L.T. Jr.

    1993-03-05

    A vapor-phase, reagent-based, fiber optic trichloroethylene (TCE) sensor developed by Lawrence Livermore National Laboratory (LLNL) was demonstrated at the Savannah River Site (SRS) in two configurations. The first incorporated the sensor into a down-well instrument bounded by two inflatable packers capable of sealing an area for discrete depth analysis. The second involved an integration of the sensor into the probe tip of the Army Corps of Engineers Waterways Experiment Station (WES) cone penetrometry system. Discrete depth measurements of vapor-phase concentrations of TCE in the vadose zone were successfully made using both configurations. These measurements demonstrate the first successful in situ sensing (as opposed to sampling) of TCE at a field site.

  11. Visualization of TCE recovery mechanisms using surfactant polymer solutions in a two-dimensional heterogeneous sand model

    NASA Astrophysics Data System (ADS)

    Robert, Thomas; Martel, Richard; Conrad, Stephen H.; Lefebvre, René; Gabriel, Uta

    2006-06-01

    This research focused on the optimization of TCE dissolution in a physical two-dimensional model providing a realistic representation of a heterogeneous granular aquifer. TCE was infiltrated in the sand pack where it resided both in pools and in zones of residual saturation. Surfactant was initially injected at low concentration to minimize TCE remobilization at first contact but was incrementally increased later during the experiment. Xanthan gum was added to the injected surfactant solution to optimize the sweep efficiency through the heterogeneous medium. Photographs and digital image analysis illustrated the interactions between TCE and the injected fluids. During the polymer flood, the effects of heterogeneities inside the sand pack were greatly reduced by the increased fluid viscosity and the shear-thinning effects of the polymer. The polymer also improved the contact between the TCE ganglia and the surfactant-polymer solution, thereby promoting dissolution. Surfactants interacted with the polymer reducing the overall viscosity of the solution. At first contact with a 0.5% mass surfactant solution, the TCE pools drained and some remobilization occurred. However, no TCE bank was formed and TCE did not penetrate into any previously uncontaminated areas. As a result, TCE surface area was increased. Subsequent surfactant floods at higher surfactant concentrations did not trigger more remobilization. TCE was mainly dissolved by the solution with the highest surfactant concentration. Plugging from bacterial growth or microgel formation associated to the polymer at the inflow screen prevented the full completion of the experiment. However, more than 90% of TCE was recovered with the circulation of less than 6 pore volumes of surfactant-polymer solution.

  12. Hydrodechlorination of TCE in a circulated electrolytic column at high flow rate.

    PubMed

    Fallahpour, Noushin; Yuan, Songhu; Rajic, Ljiljana; Alshawabkeh, Akram N

    2016-02-01

    Palladium-catalytic hydrodechlorination of trichloroethylene (TCE) by cathodic H2 produced from water electrolysis has been tested. For a field in-well application, the flow rate is generally high. In this study, the performance of Pd-catalytic hydrodechlorination of TCE using cathodic H2 is evaluated under high flow rate (1 L min(-1)) in a circulated column system, as expected to occur in practice. An iron anode supports reduction conditions and it is used to enhance TCE hydrodechlorination. However, the precipitation occurs and high flow rate was evaluated to minimize its adverse effects on the process (electrode coverage, clogging, etc.). Under the conditions of 1 L min(-1) flow, 500 mA current, and 5 mg L(-1) initial TCE concentration, removal efficacy using iron anodes (96%) is significantly higher than by mixed metal oxide (MMO) anodes (66%). Two types of cathodes (MMO and copper foam) in the presence of Pd/Al2O3 catalyst under various currents (250, 125, and 62 mA) were used to evaluate the effect of cathode materials on TCE removal efficacy. The similar removal efficiencies were achieved for both cathodes, but more precipitation generated with copper foam cathode (based on the experiments done by authors). In addition to the well-known parameters such as current density, electrode materials, and initial TCE concentration, the high velocities of groundwater flow can have important implications, practically in relation to the flush out of precipitates. For potential field application, a cost-effective and sustainable in situ electrochemical process using a solar panel as power supply is being evaluated. PMID:26344148

  13. System for In-Situ Detection of Plant Exposure to Trichloroethylene (TCE)

    NASA Technical Reports Server (NTRS)

    Lewis, Mark D. (Inventor); Anderson, Daniel J. (Inventor); Newman, Lee A. (Inventor); Keith, Amy G. (Inventor)

    2013-01-01

    A system detects a plant's exposure to trichloroethylene (TCE) through plant leaf imaging. White light impinging upon a plant's leaf interacts therewith to produce interacted light. A detector is positioned to detect at least one spectral band of the interacted light. A processor coupled to the detector performs comparisons between photonic energy of the interacted light at the one or more spectral bands thereof and reference data defining spectral responses indicative of leaf exposure to TCE. An output device coupled to the processor provides indications of the comparisons.

  14. The PACSAT Communications Experiment (PCE). Final report, August 13, 1990--February 12, 1992

    SciTech Connect

    Not Available

    1993-02-12

    While VITA (Volunteers in Technical Assistance) is the recognized world leader in low earth orbiting (LEO) satellite technology (below 1 GHz), its involvement in communications technologies is to facilitate renewable energy technology transfer to developing countries. A communications payload was incorporated into the UoSat 2 satellite (Surrey Univ., UK), launched in 1984; a prototype satellite (PCE) was also launched Jan 1990. US DOE awarded a second grant to VITA to design and test the prototype ground stations (command and field), install field ground stations in several developing country sites, pursue the operational licensing process, and transfer the evaluation results to the design of an operating system. This report covers the principal tasks of this grant.

  15. A study of the effect of perchloroethylene exposure on the reproductive outcomes of wives of dry-cleaning workers

    SciTech Connect

    Eskenazi, B.; Fenster, L.; Hudes, M.; Wyrobek, A.J.; Katz, D.F.; Gerson, J.; Rempel, D.M. )

    1991-01-01

    The purpose of this investigation was to compare the reproductive outcomes of wives of men exposed to perchloroethylene in the dry-cleaning industry compared to those of wives of laundry workers. Seventeen female partners of dry cleaners and 32 partners of laundry workers were interviewed. The number of pregnancies and the standardized fertility ratios were similar between the two groups. Wives of dry cleaners did not have higher rates of spontaneous abortions. However, wives of dry cleaners were more than twice as likely to have a history of attempting to become pregnant for more than 12 months or to have sought care for an infertility problem. Cox proportional hazards models indicated that dry-cleaners' wives had half of the per-cycle pregnancy rate of wives of laundry workers, when controlling for other potential confounders (estimated rate ratio of 0.54, 95% C.I. = 0.23, 1.27).

  16. Characterization of uranium surfaces machined with aqueous propylene glycol-borax or perchloroethylene-mineral oil coolants

    SciTech Connect

    Cristy, S.S.; Bennett, R.K. Jr.; Dillon, J.J.; Richards, H.L.; Seals, R.D.; Byrd, V.R.

    1986-12-31

    The use of perchloroethylene (perc) as an ingredient in coolants for machining enriched uranium at the Oak Ridge Y-12 Plant has been discontinued because of environmental concerns. A new coolant was substituted in December 1985, which consists of an aqueous solution of propylene glycol with borax (sodium tetraborate) added as a nuclear poison and with a nitrite added as a corrosion inhibitor. Uranium surfaces machined using the two coolants were compared with respects to residual contamination, corrosion or corrosion potential, and with the aqueous propylene glycol-borax coolant was found to be better than that of enriched uranium machined with the perc-mineral oil coolant. The boron residues on the final-finished parts machined with the borax-containing coolant were not sufficient to cause problems in further processing. All evidence indicated that the enriched uranium surfaces machined with the borax-containing coolant will be as satisfactory as those machined with the perc coolant.

  17. PD-CATALYZED TCE DECHLORINATION IN GROUNDWATER: SOLUTE EFFECTS, BIOLOGICAL CONTROL, AND OXIDATIVE CATALYST REGENERATION. (R825421)

    EPA Science Inventory

    The performance of a Pd-on-src="/ncer/pubs/images/gamma.gif">-Al2O3 catalyst for
    dechlorination of trichloroethylene (TCE) was evaluated in synthetic and real
    groundwater. Low initial TCE conversions were used to provide maximum ...

  18. Use Of Statistical Tools To Evaluate The Reductive Dechlorination Of High Levels Of TCE In Microcosm Studies

    EPA Science Inventory

    A large, multi-laboratory microcosm study was performed to select amendments for supporting reductive dechlorination of high levels of trichloroethylene (TCE) found at an industrial site in the United Kingdom (UK) containing dense non-aqueous phase liquid (DNAPL) TCE. The study ...

  19. Betula pendula: A Promising Candidate for Phytoremediation of TCE in Northern Climates.

    PubMed

    Lewis, Jeffrey; Qvarfort, Ulf; Sjöström, Jan

    2015-01-01

    Betula pendula (Silver birch) trees growing on two contaminated sites were evaluated to assess their capacity to phytoscreen and phytoremediate chlorinated aliphatic compounds and heavy metals. Both locations are industrially-contaminated properties in central Sweden. The first was the site of a trichloroethylene (TCE) spill in the 1980s while the second was polluted with heavy metals by burning industrial wastes. In both cases, sap and sapwood from Silver birch trees were collected and analyzed for either chlorinated aliphatic compounds or heavy metals. These results were compared to analyses of the surface soil, vadose zone pore air and groundwater. Silver birch demonstrated the potential to phytoscreen and possibly phytoremediate TCE and related compounds, but it did not demonstrate the ability to effectively phytoextract heavy metals when compared with hyperaccumulator plants. The capacity of Silver birch to phytoremediate TCE appears comparable to tree species that have been employed in field-scale TCE phytoremediation efforts, such as Populus spp. and Eucalyptus sideroxylon rosea. PMID:25174420

  20. Formulation design for target delivery of iron nanoparticles to TCE zones

    NASA Astrophysics Data System (ADS)

    Wang, Ziheng; Acosta, Edgar

    2013-12-01

    Nanoparticles of zero-valent iron (NZVI) are effective reducing agents for some dense non-aqueous phase liquid (DNAPL) contaminants such as trichloroethylene (TCE). However, target delivery of iron nanoparticles to DNAPL zones in the aquifer remains an elusive feature for NZVI technologies. This work discusses three strategies to deliver iron nanoparticles to DNAPL zones. To this end, iron oxide nanoparticles coated with oleate (OL) ions were used as stable analogs for NZVI. The OL-coated iron oxide nanoparticles are rendered lipophilic via (a) the addition of CaCl2, (b) acidification, or (c) the addition of a cationic surfactant, benzethonium chloride (BC). Mixtures of OL and BC show promise as a target delivery strategy due to the high stability of the nanoparticles in water, and their preferential partition into TCE in batch experiments. Column tests show that while the OL-BC coated iron oxide nanoparticles remain largely mobile in TCE-free columns, a large fraction of these particles are retained in TCE-contaminated columns, confirming the effectiveness of this target delivery strategy.

  1. EFFECTIVE REMOVAL OF TCE IN A LABORATORY MODEL OF A PRB CONSTRUCTED WITH PLANT MULCH

    EPA Science Inventory

    Ground water contaminated with TCE is commonly treated with a permeable reactive barrier (PRB) constructed with zero-valence iron. The cost of iron as the reactive matrix has driven a search for less costly alternatives, and composted plant mulch has been used as an alternative ...

  2. 77 FR 6863 - Proposed Collection; Comment Request for VITA/TCE Program Forms

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-09

    ... Internal Revenue Service offers free assistance with tax return preparation and tax counseling using... From the Federal Register Online via the Government Printing Office DEPARTMENT OF THE TREASURY Internal Revenue Service Proposed Collection; Comment Request for VITA/TCE Program Forms AGENCY:...

  3. LESSONS LEARNED FROM IN-SITU RESISTIVE HEATING OF TCE AT FORT LEWIS, WASHINGTON

    EPA Science Inventory

    The EGDY is the source of a potentially expanding, three mile long TCE plume in a sole source drinking water aquifer. Thermal remediation is being employed to reduce source mass loading to the dissolved phase aquifer plume and reduce the time to reach site cleanup goals. This i...

  4. RATE OF TCE DEGRADATION IN A PLANT MULCH PASSIVE REACTIVE BARRIER (BIOWALL)

    EPA Science Inventory

    A passive reactive barrier was installed at the OU-1 site at Altus Air Force Base, Oklahoma to treat TCE contamination in ground water from a landfill. Depth to ground water varies from 1.8 to 2.4 meters below land surface. To intercept and treat the plume of contaminated groun...

  5. FIELD SCALE EVALUATION OF TREATMENT OF TCE IN A BIOWALL AT THE OU-1 SITE

    EPA Science Inventory

    A passive reactive barrier (Biowall) was installed at the OU-1 site at Altus Air Force Base, Oklahoma to treat TCE contamination in ground water from a landfill. Depth to ground water varies from 1.8 to 2.4 meters below land surface. To intercept and treat the plume of contamin...

  6. REMEDIATION OF TCE-CONTAMINATED GROUNDWATER BY A PERMEABLE REACTIVE BARRIER FILLED WITH PLANT MULCH (BIOWALL)

    EPA Science Inventory

    A pilot-scale permeable reactive barrier filled with plant mulch was installed at Altus Air Force Base (in Oklahoma, USA) to treat trichloroethylene (TCE) contamination in ground water emanating from a landfill. The barrier was constructed in June 2002. It was 139 meters long, 7 ...

  7. Abiotic and Biotic Transformation of TCE under Sulfate Reducing Conditions: the Role of Spatial Heterogeneity

    EPA Science Inventory

    At a number of sites in the USA, passive reactive barriers built with shredded plant mulch have been constructed to treat ground water contaminated with TCE. These barriers are called biowalls because anaerobic biodegradation of the plant mulch is expected to provide substrates...

  8. A SEARCH FOR RESIDUAL BEHAVIORAL EFFECTS OF TRICHLOROETHYLENE (TCE) IN RATS EXPOSED AS YOUNG ADULTS

    EPA Science Inventory

    Trichloroethylene (TCE) is a solvent of concern to the EPA due to its extensive use in industry, its prevalence in urban air, and its appearance in water supplies. Human clinical studies have associated short and long-termsolvent exposures with cognitive dysfunction including att...

  9. INFLUENCE OF HYDRAULIC RETENTION TIME ON EXTENT OF PCE DECHLORINATION AND PRELIMINARY CHARACTERIZATION OF THE ENRICHMENT CULTURE. (R826694C703)

    EPA Science Inventory

    The extent of tetrachloroethene (PCE) dechlorination in two chemostats was evaluated as a function of hydraulic retention time (HRT). The inoculum of these chemostats was from an upflow anaerobic sludge blanket (UASB) reactor that rapidly converts PCE to vinyl chloride (VC) an...

  10. Fingerprinting TCE in a bedrock aquifer using compound-specific isotope analysis.

    PubMed

    Lojkasek-Lima, Paulo; Aravena, Ramon; Parker, Beth L; Cherry, John A

    2012-01-01

    A dual isotope approach based on compound-specific isotope analysis (CSIA) of carbon (C) and chlorine (Cl) was used to identify sources of persistent trichloroethylene (TCE) that caused the shut-down in 1994 of a municipal well in an extensive fractured dolostone aquifer beneath Guelph, Ontario. Several nearby industrial properties have known subsurface TCE contamination; however, only one has created a comprehensive monitoring network in the bedrock. The impacted municipal well and many monitoring wells were sampled for volatile organic compounds (VOCs), inorganic parameters, and CSIA. A wide range in isotope values was observed at the study site. The TCE varies between -35.6‰ and -21.8‰ and from 1.6‰ to 3.2‰ for ?(13) C and ?(37) Cl, respectively. In case of cis-1,2-dichloroethene, the isotope values range between -36.3‰ and -18.9‰ and from 2.4‰ to 4.7‰ for ?(13) C and ?(37) Cl, respectively. The dual isotope approach represented by a plot of ?(13) C vs. ?(37) Cl shows the municipal well samples grouped in a domain clearly separate from all other samples from the property with the comprehensive well network. The CSIA results collected under non-pumping and short-term pumping conditions thus indicate that this particular property, which has been studied intensively for several years, is not a substantial contributor of the TCE presently in the municipal well under non-pumping conditions. This case study demonstrates that CSIA signatures would have been useful much earlier in the quest to examine sources of the TCE in the municipal well if bedrock monitoring wells had been located at several depths beneath each of the potential TCE-contributing properties. Moreover, the CSIA results show that microbial reductive dechlorination of TCE occurs in some parts of the bedrock aquifer. At this site, the use of CSIA for C and Cl in combination with analyses of VOC and redox parameters proved to be important due to the complexity introduced by biodegradation in the complex fractured rock aquifer. It is highly recommended to revisit the study when the municipal well is back into full operation. PMID:22220911

  11. Preliminary technology report for Southern Sector bioremediation

    SciTech Connect

    Brigmon, R.L.; White, R.; Hazen, T.C.; Jones, D.; Berry, C.

    1997-06-01

    This project was designed to demonstrate the potential of intrinsic bioremediation and phytoremediation in the Southern Sector of the A/M-Area at the Savannah River Site. A subsurface plume of trichloroethylene (TCE) and perchloroethylene (PCE) is present in the Lost Lake aquifer upgradient of the study site and is predicted to impact the area at some point in the future. The surface area along the Lost lake aquifer seep line where the plume is estimated to emerge was identified. Ten sites along the seep line were selected for biological, chemical, and contaminant treatability analyses. A survey was undertaken in this area to to quantify the microbial and plant population known to be capable of remediating TCE and PCE. The current groundwater quality upgradient and downgradient of the zone of influence was determined. No TCE or PCE was found in the soils or surface water from the area tested at this time. A TCE biodegradation treatability test was done on soil from the 10 selected locations. From an initial exposure of 25 ppm of TCE, eight of the samples biodegraded up to 99.9 percent of all the compound within 6 weeks. This biodegradation of TCE appears to be combination of aerobic and anaerobic microbial activity as intermediates that were detected in the treatability test include vinyl chloride (VC) and the dichloroethenes (DCE) 1,2-cis-dichloroethylene and 1,1-dichloroethylene. The TCE biological treatability studies were combines with microbiological and chemical analyses. The soils were found through immunological analysis with direct fluorescent antibodies (DFA) and microbiological analysis with direct fluorescent antibodies (DFA) and microbiological analysis to have a microbial population of methanotrophic bacteria that utilize the enzyme methane monooxygenase (MMO) and cometabolize TCE.

  12. Validation and application of pharmacokinetic models for interspecies extrapolations in toxicity risk assessments of volatile organics. Annual report No. 2, 1 July 1988-30 June 1989

    SciTech Connect

    Dallas, C.E.; Bruckner, J.V.; Gallo, J.; Ramanathan, R.; Muralidhara, S.

    1989-07-21

    In pursuit of the goal of establishing a scientific basis for the interspecies extrapolation of pharmacokinetic data in health-risk assessments, a series of studies were conducted involving pharmacokinetic determinations in rats to several aliphatic halocarbons (with parallel studies initiated in the dog). Direct measurements of the uptake and elimination of halocarbon in rats were completed during the following inhalation exposures and following oral administration of dichloroethylene (DCE) and perchloroethylene (PCE). An assay for the measurement of halocarbons in the tissues of exposed animals has been successfully developed, and tissue-concentration profiles in the liver, kidney, lung, fat, brain, muscle, and heart were completed for oral and intraarterial administrations of PCE. The utility of the physiologically-based pharmacokinetic model for the accurate computer simulations of the pharmacokinetics of three halocarbons with wide variation in physicochemical properties (TRI, TCE, and PCE) has been demonstrated.

  13. Optimizing binary phase and amplitude filters for PCE, SNR, and discrimination

    NASA Technical Reports Server (NTRS)

    Downie, John D.

    1992-01-01

    Binary phase-only filters (BPOFs) have generated much study because of their implementation on currently available spatial light modulator devices. On polarization-rotating devices such as the magneto-optic spatial light modulator (SLM), it is also possible to encode binary amplitude information into two SLM transmission states, in addition to the binary phase information. This is done by varying the rotation angle of the polarization analyzer following the SLM in the optical train. Through this parameter, a continuum of filters may be designed that span the space of binary phase and amplitude filters (BPAFs) between BPOFs and binary amplitude filters. In this study, we investigate the design of optimal BPAFs for the key correlation characteristics of peak sharpness (through the peak-to-correlation energy (PCE) metric), signal-to-noise ratio (SNR), and discrimination between in-class and out-of-class images. We present simulation results illustrating improvements obtained over conventional BPOFs, and trade-offs between the different performance criteria in terms of the filter design parameter.

  14. Radiation induced dechlorination of some chlorinated hydrocarbons in aqueous suspensions of various solid particles

    NASA Astrophysics Data System (ADS)

    Mú?ka, V.; Bu?ata, M.; ?uba, V.; Silber, R.; Juha, L.

    2015-07-01

    Radiation induced dechlorination of trichloroethylene (TCE) and tetrachloroethylene (PCE) in aqueous solutions containing the active carbon (AC) or cupric oxide (CuO) as the modifiers was studied. The obtained results were compared to the previously studied dechlorination of polychlorinated biphenyls (PCBs). Both modifiers were found to decrease the efficiency of dechlorination. The AC modifier acts mainly via adsorption of the aliphatic (unlike the aromatic) hydrocarbons and the CuO oxide mainly inhibits the mineralization of the perchloroethylene. The results presented in this paper will be also helpful for the studies of the impact of chlorinated hydrocarbons on the membrane permeability of living cells.

  15. Retaining and recovering enzyme activity during degradation of TCE by methanotrophs

    SciTech Connect

    Palumbo, A.V.; Strong-Gunderson, J.M.; Carroll, S.

    1997-12-31

    To determine if compounds added during trichloroethylene (TCE) degradation could reduce the loss of enzyme activity or increase enzyme recovery, different compounds serving as energy and carbon sources, pH buffers, or free radical scavengers were tested. Formate and formic acid (reducing power and a carbon source), as well as ascorbic acid and citric acid (free radical scavengers) were added during TCE degradation at a concentration of 2 mM. A saturated solution of calcium carbonate was also tested to address pH concerns. In the presence of formate and methane, only calcium carbonate and formic acid had a beneficial effect on enzyme recovery. The calcium carbonate and formic acid both reduced the loss of enzyme activity and resulted in the highest levels of enzyme activity after recovery. 19 refs., 3 figs.

  16. Case study: In-situ methods for the recovery of dissolved and free-phase TCE

    SciTech Connect

    Lindhult, E.C.; Edelman, M.J.; Buggey, T.R.; Hart, M.A.

    1997-12-31

    Two-phase vacuum extraction (VE) technology, which simultaneously removes groundwater and soil vapor from the subsurface, has been applied at a dense non-aqueous phase liquid (DNAPL) site with promising results. The two-phase VE (a.k.a. dual-phase VE) has been used to enhance groundwater recovery to attain a zone of capture by enhancing groundwater yields from groundwater recovery wells not attainable from pumping alone. Operation of the two-phase VE system has resulted in the recovery of significant quantities of DNAPL, consisting primarily of trichloroethylene (TCE). Controlled pumping has been applied to recover the free-phase TCE. This paper presents a summary of site conditions, description of the two-phase VE and groundwater remediation system, and conclusions from the site remediation.

  17. In Situ Redox Manipulation of Subsurface Sediments from Fort Lewis, Washington: Iron Reduction and TCE Dechlorination Mechanisms

    SciTech Connect

    Szecsody, James E.; Fruchter, Jonathan S.; Sklarew, Deborah S.; Evans, John C.

    2000-03-17

    The feasibility of chemically treating sediments from the Ft. Lewis, Washington, Logistics Center to develop a permeable barrier for dechlorination of TCE was investigated in a series of laboratory experiments.

  18. Electrochemically induced dual reactive barriers for transformation of TCE and mixture of contaminants in groundwater

    PubMed Central

    Mao, Xuhui; Yuan, Songhu; Fallahpour, Noushin; Ciblak, Ali; Howard, Joniqua; Padilla, Ingrid; Loch-Caruso, Rita; Alshawabkeh, Akram N.

    2012-01-01

    A novel reactive electrochemical flow system consisting of iron anode and porous cathode is proposed for the remediation of mixture of contaminants in groundwater. The system consists of a series of sequentially arranged electrodes, a perforated iron anode, a porous copper cathode followed by a mesh-type mixed metal oxide anode. The iron anode generates ferrous species and a chemically reducing environment, the porous cathode provides a reactive electrochemically reducing barrier, and the inert anode provides proton and oxygen to neutralize the system. The redox conditions of the electrolyte flowing through this system can be regulated by controlling the distribution of the electric current. Column experiments are conducted to evaluate the process and study the variables. The electrochemical reduction on a copper foam cathode produced an electrode-based reductive potential capable of reducing TCE and nitrate. Rational electrodes arrangement, longer residence time of electrolytes and higher surface area of foam electrode improve the reductive transformation of TCE. More than 82.2% TCE removal efficiency is achieved for the case of low influent concentration (< 7.5 mg/L) and high current (> 45 mA). The ferrous species produced from the iron anode not only enhance the transformation of TCE on the cathode, but also facilitates transformation of other contaminants including dichromate, selenate and arsenite. Removal efficiencies greater than 80% are achieved for these contaminants from flowing contaminated water. The overall system, comprising the electrode-based and electrolyte-based barriers, can be engineered as a versatile and integrated remedial method for a relatively wide spectrum of contaminants and their mixtures. PMID:23067023

  19. The role of microbial reductive dechlorination of TCE at a phytoremediation site

    USGS Publications Warehouse

    Godsy, E.M.; Warren, E.; Paganelli, V.V.

    2003-01-01

    In April 1996, a phytoremediation field demonstration site at the Naval Air Station, Fort Worth, Texas, was developed to remediate shallow oxic ground water (< 3.7 m deep) contaminated with chlorinated ethenes. Microbial populations were sampled in February and June 1998. The populations under the newly planted cottonwood trees had not yet matured to an anaerobic community that could dechlorinate trichloroethene (TCE) to cis-1,2-dichloroethene (DCE); however, the microbial population under a mature (???22-year-old) cottonwood tree about 30 m southwest of the plantings had a mature anaerobic population capable of dechlorinating TCE to DCE, and DCE to vinyl chloride (VC). Oxygen-free sediment incubations with contaminated groundwater also demonstrated that resident microorganisms were capable of the dechlorination of TCE to DCE. This suggests that a sufficient amount of organic material is present for microbial dechlorination in aquifer microniches where dissolved O2 concentrations are low. Phenol, benzoic acid, acetic acid, and a cyclic hydrocarbon, compounds consistent with the degradation of root exudates and complex aromatic compounds, were identified by gas chromatography/mass spectrometry (GC/MS) in sediment samples under the mature cottonwood tree. Elsewhere at the site, transpiration and degradation by the cottonwood trees appears to be responsible for loss of chlorinated ethenes.

  20. In situ detection of organic molecules: Optrodes for TCE (trichloroethylene) and CHCl sub 3

    SciTech Connect

    Angel, S. M.; Langry, K. C.; Ridley, M. N.

    1990-05-01

    We have developed new absorption-based chemical indicators for detecting chloroform (CHCl{sub 3}) and trichloroethylene (TCE). These indicators were used to make very sensitive optical chemical sensors (optrodes) for each of these two contaminants. Concentrations below 10 ppb can be accurately measured using these sensors. Furthermore, they are selective and do not response to similar contaminants commonly found with TCE and CHCl{sub 3} in contaminated groundwater. In addition, the sensor response is linearly proportional to the chemical concentration. In this report, we describe the details of this optrode and the putative reaction sequences of the indicator chemistries with CHCl{sub 3} and TCE and present an analysis of the spectral data obtained from the reaction products. A key part of the development of this optrode was designing a simple readout device. The readout is a dual-channel fiber-optic fluorimeter modified to measure transmission or absorption of light. The system is controlled by a lap-top microcomputer and is fully field portable. In addition to describing the final absorption optrode, details of the chemical indicator reactions are presented for both absorption- (colorimetric) and fluorescence-based optrodes. Finally, we report on the syntheses of several compounds used to evaluate the indicator chemical reactions that led to the development of the absorption optrode. 23 refs., 26 figs., 1 tab.

  1. Long Term Remote Monitoring of TCE Contaminated Groundwater at Savannah River Site

    SciTech Connect

    Duran, C.; Gudavalli, R.; Lagos, L.; Tansel, B.; Varona, J.; Allen, M.

    2004-10-06

    The purpose of this study was to develop a mobile self powered remote monitoring system enhanced for field deployment at Savannah River Site (SRS). The system used a localized power source with solar recharging and has wireless data collection, analysis, transmission, and data management capabilities. The prototype was equipped with a Hydrolab's DataSonde 4a multi-sensor array package managed by a Supervisory Control and Data Acquisition (SCADA) system, with an adequate pumping capacity of water samples for sampling and analysis of Trichloroethylene (TCE) in contaminated groundwater wells at SRS. This paper focuses on a study and technology development efforts conducted at the Hemispheric Center for Environmental Technology (HCET) at Florida International University (FIU) to automate the sampling of contaminated wells with a multi-sensor array package developed using COTS (Commercial Off The shelf) parts. Bladder pumps will pump water from different wells to the sensors array, water quality TCE indicator parameters are measured (i.e. pH, redox, ORP, DO, NO3 -, Cl-). In order to increase user access and data management, the system was designed to be accessible over the Internet. Remote users can take sample readings and collect data remotely over a web. Results obtained at Florida International University in-house testing and at a field deployment at the Savannah River Site indicate that this long term monitoring technique can be a feasible solution for the sampling of TCE indicator parameters at remote contaminated sites.

  2. Halocarbon adsorption in nanoporous materials: A combined calorimetric and Monte Carlo study of trichloroethylene (TCE) in faujasite-type zeolites

    SciTech Connect

    Mellot, C.F.; Cheetham, A.K.; Harms, S.; Savitz, S.; Gorte, R.J.; Myers, A.L.

    1998-11-10

    Isosteric heats of adsorption of trichloroethylene (TCE) in a series of faujasite-type zeolites, siliceous faujasite, NaY (Si:Al = 2.6), and NaX (Si:Al = 1.2), have been studied by the combination of calorimetry and (N,V,T) Monte Carlo simulations, varying the sorbate loading up to {approximately}35 molecules per unit-cell. Excellent agreement is obtained between observed and calculated heats, confirming the applicability of the force field to the realm of unsaturated halocarbons for a large range of Si:Al ratio, cation content, and sorbate loading. The relative contributions of short-range and long-range interactions to the heat of adsorption are discussed, and the host/guest pair distribution functions (PDFs) from the MC simulations are analyzed in detail. At fixed loading, TCE heats of adsorption increase in the sequence of host basicity and cation content: siliceous faujasite: {approximately}40 kJ/mol < NaY: {approximately}55 kJ/mol < NaX: {approximately}80 kJ/mol (extrapolated to zero loading). Such a correlation is further elucidated from the host/guest PDFs by the enhancement of H{sub TCE}{hor_ellipsis}O{sub ZEO} hydrogen bonding and Cl{sub TCE}{hor_ellipsis}Na{sub ZEO} electrostatic interactions from the siliceous faujasite to NaY and NaX. An increase in TCE loading gives rise to a systematic increase in adsorption heats (>10 kJ/mol); this is identified as of a predominantly dispersive nature arising from Cl{sub TCE}{hor_ellipsis} and H{sub TCE}{hor_ellipsis}Cl{sub TCE} intermolecular interactions.

  3. Toward Distributed Translucent Wavelength Switched Optical Networks under GMPLS/PCE Architecture

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Chap, Tithra; Xu, Sugang; Tanaka, Yoshiaki

    Recently, the GMPLS controlled WSON has emerged as a promising optical transport network. In order to guarantee the optical signal transmission feature without deformation, the optoelectronic 3R regenerators still need to be sparsely placed in the network, termed as translucent networks. The growing size and complexity of the translucent network requires a transition of control plane to move from the traditional centralized model to a fully distributed architecture in the future. However, centrally designed routing, wavelength assignment, and 3R regenerator allocation approaches become unfeasible under the distributed paradigm due to the outdated and inconsistent network state information. A common solution is to accelerate the update frequency of network state, but the fundamental problem remains that the inaccurate state information is still inevitable. Furthermore, it adds a significant increase to the control traffic volume which adversely degrades the performance and scalability of the network control system. In order to mitigate the impact of having inaccurate state information on network performance in the distributed systems, a novel RWA approach is proposed in this paper, termed as routing and distributed wavelength assignment with top ranked probing wavelength set computation. In our proposal, the wavelength assignment is performed by signalling process with a set of carefully preselected probing wavelengths. This set is dynamically computed based on the resource utilization each time the network state is refreshed. The PCE module is adopted in WSON control plane to be responsible for the computation of RWA and 3R allocation. The performance of the proposed approach is studied by extensive simulations. The experiment results reveal that by employing the proposed scheme, without loss on the blocking performance the inaccuracy of the wavelength availability information can be well tolerated, and the set-up delay in lightpath provisioning can be kept at a low level.

  4. Spatial and temporal dynamics of organohalide-respiring bacteria in a heterogeneous PCE-DNAPL source zone

    NASA Astrophysics Data System (ADS)

    Cápiro, Natalie L.; Löffler, Frank E.; Pennell, Kurt D.

    2015-11-01

    Effective treatment of sites contaminated with dense non-aqueous phase liquids (DNAPLs) requires detailed understanding of the microbial community responses to changes in source zone strength and architecture. Changes in the spatial and temporal distributions of the organohalide-respiring Dehalococcoides mccartyi (Dhc) strains and Geobacter lovleyi strain SZ (GeoSZ) were examined in a heterogeneous tetrachloroethene- (PCE-) DNAPL source zone within a two-dimensional laboratory-scale aquifer flow cell. As part of a combined remedy approach, flushing with 2.3 pore volumes (PVs) of 4% (w/w) solution of the nonionic, biodegradable surfactant Tween® 80 removed 55% of the initial contaminant mass, and resulted in a PCE-DNAPL distribution that contained 51% discrete ganglia and 49% pools (ganglia-to-pool ratio of 1.06). Subsequent bioaugmentation with the PCE-to-ethene-dechlorinating consortium BDI-SZ resulted in cis-1,2-dichloroethene (cis-DCE) formation after 1 PV (ca. 7 days), while vinyl chloride (VC) and ethene were detected 10 PVs after bioaugmentation. Maximum ethene yields (ca. 90 ?M) within DNAPL pool and ganglia regions coincided with the detection of the vcrA reductive dehalogenase (RDase) gene that exceeded the Dhc 16S rRNA genes by 2.0 ± 1.3 and 4.0 ± 1.7 fold in the pool and ganglia regions, respectively. Dhc and GeoSZ cell abundance increased by up to 4 orders-of-magnitude after 28 PVs of steady-state operation, with 1 to 2 orders-of-magnitude increases observed in close proximity to residual PCE-DNAPL. These observations suggest the involvement of these dechlorinators the in observed PCE dissolution enhancements of up to 2.3 and 6.0-fold within pool and ganglia regions, respectively. Analysis of the solid and aqueous samples at the conclusion of the experiment revealed that the highest VC (? 155 ?M) and ethene (? 65 ?M) concentrations were measured in zones where Dhc and GeoSZ were predominately attached to the solids. These findings demonstrate dynamic responses of organohalide-respiring bacteria in a heterogeneous DNAPL source zone, and emphasize the influence of source zone architecture on bioremediation performance.

  5. Spatial and temporal dynamics of organohalide-respiring bacteria in a heterogeneous PCE-DNAPL source zone.

    PubMed

    Cápiro, Natalie L; Löffler, Frank E; Pennell, Kurt D

    2015-11-01

    Effective treatment of sites contaminated with dense non-aqueous phase liquids (DNAPLs) requires detailed understanding of the microbial community responses to changes in source zone strength and architecture. Changes in the spatial and temporal distributions of the organohalide-respiring Dehalococcoides mccartyi (Dhc) strains and Geobacter lovleyi strain SZ (GeoSZ) were examined in a heterogeneous tetrachloroethene- (PCE-) DNAPL source zone within a two-dimensional laboratory-scale aquifer flow cell. As part of a combined remedy approach, flushing with 2.3 pore volumes (PVs) of 4% (w/w) solution of the nonionic, biodegradable surfactant Tween® 80 removed 55% of the initial contaminant mass, and resulted in a PCE-DNAPL distribution that contained 51% discrete ganglia and 49% pools (ganglia-to-pool ratio of 1.06). Subsequent bioaugmentation with the PCE-to-ethene-dechlorinating consortium BDI-SZ resulted in cis-1,2-dichloroethene (cis-DCE) formation after 1 PV (ca. 7days), while vinyl chloride (VC) and ethene were detected 10 PVs after bioaugmentation. Maximum ethene yields (ca. 90?M) within DNAPL pool and ganglia regions coincided with the detection of the vcrA reductive dehalogenase (RDase) gene that exceeded the Dhc 16S rRNA genes by 2.0±1.3 and 4.0±1.7 fold in the pool and ganglia regions, respectively. Dhc and GeoSZ cell abundance increased by up to 4 orders-of-magnitude after 28 PVs of steady-state operation, with 1 to 2 orders-of-magnitude increases observed in close proximity to residual PCE-DNAPL. These observations suggest the involvement of these dechlorinators the in observed PCE dissolution enhancements of up to 2.3 and 6.0-fold within pool and ganglia regions, respectively. Analysis of the solid and aqueous samples at the conclusion of the experiment revealed that the highest VC (?155?M) and ethene (?65?M) concentrations were measured in zones where Dhc and GeoSZ were predominately attached to the solids. These findings demonstrate dynamic responses of organohalide-respiring bacteria in a heterogeneous DNAPL source zone, and emphasize the influence of source zone architecture on bioremediation performance. PMID:26348832

  6. Factors Affecting the Reactivity, Efficiency, and Lifetime of Iron Nanoparticles for In Situ Degradation of TCE

    NASA Astrophysics Data System (ADS)

    Lowry, G. V.; Liu, Y.; Majetich, S.

    2003-12-01

    Over the past decade, laboratory and field studies have demonstrated that Fe0 can rapidly transform dissolved chlorinated organic solvents into non-toxic compounds. Using nanoscale Fe0 (\\~100nm particles) offers a host of novel in situ subsurface remediation options because particles can be delivered into the small pores of porous media where residual contamination resides. Using Fe0 nanoparticles for in situ groundwater remediation is a recent nanotechnology application and little is known about the optimal properties for these particles. The objective of this research is to determine the factors controlling reactivity, lifetime, and efficiency of Fe0 nanoparticles so more reactive and efficient Fe0 nanoparticles can be developed. The physical and chemical properties of two types of Fe0 nanoparticles; Fe0 (AR-2, Toda America, Inc.) and Boron-doped Fe0 particles synthesized by NaBH4 reduction of Fe2+(aq) (Fe0/B) were determined before and after reaction with TCE in water using TEM, HRTEM, magnetometry, BET N2 adsorption, electron diffraction, and ICP-AES. The TCE transformation rate and efficiency (% of total Fe oxidized used to dechlorinate TCE) afforded by each type of particle were measured. Under identical reaction conditions, Fe0 nanoparticles (kobs=0.013 Lg-1d-1) are ~2 orders of magnitude less reactive than boron-doped (Fe0/B) particles (kobs=1.3 Lg-1d-1). The oxidized surface of Fe0 nanoparticles prevents them from corroding and limits the rate of TCE dechlorination. The presence of boron appears to mitigate this effect. Although the Fe0/B particles are highly reactive, HRTEM shows a clear core-shell composition of these particles before reaction. Dissolution of the boron-containing oxide layer formed on the Fe0/B particles may be responsible for their higher reactivity. TEM indicates the presence of acicular 200nm by 15nm a-Fe2O3 particles in Fe0/B particles that have been fully reacted with TCE in water, suggesting that the Fe-oxides formed away from the Fe0/B particle surface. The efficiency of completely reacted Fe0/B particles was relatively low at ~10%. This indicates a tradeoff between reaction rate and efficiency, and suggests that optimal Fe0-based nanoparticles may not necessarily be those that afford the fastest dechlorination rates.

  7. Development and evaluation of a harmonized physiologically based pharmacokinetic (PBPK) model for perchloroethylene toxicokinetics in mice, rats, and humans

    SciTech Connect

    Chiu, Weihsueh A.; Ginsberg, Gary L.

    2011-06-15

    This article reports on the development of a 'harmonized' PBPK model for the toxicokinetics of perchloroethylene (tetrachloroethylene or perc) in mice, rats, and humans that includes both oxidation and glutathione (GSH) conjugation of perc, the internal kinetics of the oxidative metabolite trichloroacetic acid (TCA), and the urinary excretion kinetics of the GSH conjugation metabolites N-Acetylated trichlorovinyl cysteine and dichloroacetic acid. The model utilizes a wider range of in vitro and in vivo data than any previous analysis alone, with in vitro data used for initial, or 'baseline,' parameter estimates, and in vivo datasets separated into those used for 'calibration' and those used for 'evaluation.' Parameter calibration utilizes a limited Bayesian analysis involving flat priors and making inferences only using posterior modes obtained via Markov chain Monte Carlo (MCMC). As expected, the major route of elimination of absorbed perc is predicted to be exhalation as parent compound, with metabolism accounting for less than 20% of intake except in the case of mice exposed orally, in which metabolism is predicted to be slightly over 50% at lower exposures. In all three species, the concentration of perc in blood, the extent of perc oxidation, and the amount of TCA production is well-estimated, with residual uncertainties of {approx} 2-fold. However, the resulting range of estimates for the amount of GSH conjugation is quite wide in humans ({approx} 3000-fold) and mice ({approx} 60-fold). While even high-end estimates of GSH conjugation in mice are lower than estimates of oxidation, in humans the estimated rates range from much lower to much higher than rates for perc oxidation. It is unclear to what extent this range reflects uncertainty, variability, or a combination. Importantly, by separating total perc metabolism into separate oxidative and conjugative pathways, an approach also recommended in a recent National Research Council review, this analysis reconciles the disparity between those previously published PBPK models that concluded low perc metabolism in humans and those that predicted high perc metabolism in humans. In essence, both conclusions are consistent with the data if augmented with some additional qualifications: in humans, oxidative metabolism is low, while GSH conjugation metabolism may be high or low, with uncertainty and/or interindividual variability spanning three orders of magnitude. More direct data on the internal kinetics of perc GSH conjugation, such as trichlorovinyl glutathione or tricholorvinyl cysteine in blood and/or tissues, would be needed to better characterize the uncertainty and variability in GSH conjugation in humans. - Research Highlights: >We analyze perchloroethylene (perc) toxicokinetics with a physiological model. >Results from previous analyses lumping metabolic pathways are inconsistent. >Separately tracking oxidation and conjugation pathways reconciles these results. >Available data are adequate for predicting perc blood levels and oxidation by P450. >High uncertainty remains for human conjugation of perc with glutathione.

  8. Use of statistical tools to evaluate the reductive dechlorination of high levels of TCE in microcosm studies

    NASA Astrophysics Data System (ADS)

    Harkness, Mark; Fisher, Angela; Lee, Michael D.; Mack, E. Erin; Payne, Jo Ann; Dworatzek, Sandra; Roberts, Jeff; Acheson, Carolyn; Herrmann, Ronald; Possolo, Antonio

    2012-04-01

    A large, multi-laboratory microcosm study was performed to select amendments for supporting reductive dechlorination of high levels of trichloroethylene (TCE) found at an industrial site in the United Kingdom (UK) containing dense non-aqueous phase liquid (DNAPL) TCE. The study was designed as a fractional factorial experiment involving 177 bottles distributed between four industrial laboratories and was used to assess the impact of six electron donors, bioaugmentation, addition of supplemental nutrients, and two TCE levels (0.57 and 1.90 mM or 75 and 250 mg/L in the aqueous phase) on TCE dechlorination. Performance was assessed based on the concentration changes of TCE and reductive dechlorination degradation products. The chemical data was evaluated using analysis of variance (ANOVA) and survival analysis techniques to determine both main effects and important interactions for all the experimental variables during the 203-day study. The statistically based design and analysis provided powerful tools that aided decision-making for field application of this technology. The analysis showed that emulsified vegetable oil (EVO), lactate, and methanol were the most effective electron donors, promoting rapid and complete dechlorination of TCE to ethene. Bioaugmentation and nutrient addition also had a statistically significant positive impact on TCE dechlorination. In addition, the microbial community was measured using phospholipid fatty acid analysis (PLFA) for quantification of total biomass and characterization of the community structure and quantitative polymerase chain reaction (qPCR) for enumeration of Dehalococcoides organisms (Dhc) and the vinyl chloride reductase (vcrA) gene. The highest increase in levels of total biomass and Dhc was observed in the EVO microcosms, which correlated well with the dechlorination results.

  9. Risk of Learning and Behavioral Disorders Following Prenatal and Early Postnatal Exposure to Tetrachloroethylene (PCE)-contaminated Drinking Water

    PubMed Central

    Janulewicz, Patricia A; White, Roberta F; Winter, Michael R; Weinberg, Janice M; Gallagher, Lisa E; Vieira, Veronica; Webster, Thomas F; Aschengrau, Ann

    2008-01-01

    This population-based retrospective cohort study examined the association between developmental disorders of learning, attention and behavior and prenatal and early postnatal drinking water exposure to tetrachloroethylene (PCE) on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and a Geographic Information System (GIS). Mothers completed a questionnaire on disorders of attention, learning and behavior in their children and on potential confounding variables. The final cohort consisted of 2,086 children. Results of crude and multivariate analyses showed no association between prenatal exposure and receiving tutoring for reading or math, being placed on an Individual Education Plan, or repeating a school grade (adjusted Odds Ratios (OR)=1.0–1.2). There was also no consistent pattern of increased risk for receiving a diagnosis of Attention Deficit Disorder (ADD) or Hyperactive Disorder (HD), special class placement for academic or behavioral problems, or lower educational attainment. Modest associations were observed for the latter outcomes only in the low exposure group (e.g., adjusted ORs for ADD were 1.4 and 1.0 for low and high exposure, respectively). (All ORs are based on an unexposed referent group.) Results for postnatal exposure through age five years were similar to those for prenatal exposure. We conclude that prenatal and early postnatal PCE exposure is not associated with disorders of attention, learning and behavior identified on the basis of questionnaire responses and at the exposure levels experienced by this population. PMID:18353612

  10. Risk of learning and behavioral disorders following prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water.

    PubMed

    Janulewicz, Patricia A; White, Roberta F; Winter, Michael R; Weinberg, Janice M; Gallagher, Lisa E; Vieira, Veronica; Webster, Thomas F; Aschengrau, Ann

    2008-01-01

    This population-based retrospective cohort study examined the association between developmental disorders of learning, attention and behavior and prenatal and early postnatal drinking water exposure to tetrachloroethylene (PCE) on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and a Geographic Information System (GIS). Mothers completed a questionnaire on disorders of attention, learning and behavior in their children and on potential confounding variables. The final cohort consisted of 2086 children. Results of crude and multivariate analyses showed no association between prenatal exposure and receiving tutoring for reading or math, being placed on an Individual Education Plan, or repeating a school grade (adjusted Odds Ratios (OR)=1.0-1.2). There was also no consistent pattern of increased risk for receiving a diagnosis of Attention Deficit Disorder (ADD) or Hyperactive Disorder (HD), special class placement for academic or behavioral problems, or lower educational attainment. Modest associations were observed for the latter outcomes only in the low exposure group (e.g., adjusted ORs for ADD were 1.4 and 1.0 for low and high exposure, respectively). (All ORs are based on an unexposed referent group.) Results for postnatal exposure through age five years were similar to those for prenatal exposure. We conclude that prenatal and early postnatal PCE exposure is not associated with disorders of attention, learning and behavior identified on the basis of questionnaire responses and at the exposure levels experienced by this population. PMID:18353612

  11. The influence of different geotechnically relevant amendments on the reductive degradation of TCE by nZVI

    NASA Astrophysics Data System (ADS)

    Freitag, Peter; Schöftner, Philipp; Waldner, Georg; Reichenauer, Thomas G.; Nickel, Claudia; Spitz, Marcus; Dietzel, Martin

    2014-05-01

    Trichloroethylene (TCE) was widely used as a cleaning and degreasing agent. Companies needing these agents were often situated in or close to built up areas, so spillage led to contaminated sites which now can only be remediated using in situ techniques. The situation is compounded by the fact that TCE tends to seep through ground water bodies forming pools at the bottom of the aquifer. When reacting with TCE, nanoscale zero valent iron (nZVI) is known to reduce it into non-toxic substances. The difficulty is to bring it in contact with the pollutant. Attempts using passive insertion into the groundwater via wells yielded mixed results. Reasons for this are that ZVI tends to coagulate, to sediment and to adsorb on the matrix of the aquifer. Also, in inhomogeneous aquifers a passive application of nZVI can be difficult and might not bring the desired results, due to existence of preferential flow paths. A possible solution to this problem is the physical in situ mixing of ZVI into the contaminant source. This can, in principle, be done by adapting jet grouting - a method that uses a high pressure slurry jet, consisting of water and geotechnical additives ("binders"), to mix and compact zones ("columns") in soil. These columns are commonly used to solve foundation problems but can also be used to solve the problem of delivering nZVI to TCE source zones. This paper examines the influence binders have on the degradation reaction between TCE and nZVI. The necessity of these binders is explained by the fact that the subsoil structure is rearranged during the jetting process leading to subsidence on the surface. These subsidences could result in damage to neighbouring structures. A series of batch experiments was conducted in this study. Contaminated groundwater was brought into contact with samples of slurries commonly used in geotechnical applications. We tested the effects of concresole, bentonite, zeolithe, fly ash, slag sand and cement on the kinetics of TCE degradation by nZVI. The degradation of TCE was measured using GC Headspace samples. Furthermore, additional experiments were conducted to investigate the interaction between binders and TCE as well as binders and nZVI. The results of these experiments led to the conclusion that jet grouting could be well suited for the delivery of nZVI to TCE contaminated source zones. Currently, soil column experiments and large-scale experiments in test facilities are performed to confirm the batch testing results.

  12. Solar light induced degradation of trichloroethylene (TCE) using TiO2: effects of solar light intensity and seasonal variations.

    PubMed

    Park, Jaehong; Choi, Euiso; Cho, Il-Hyoung; Kim, Young-Gyu

    2003-09-01

    The feasibility of the trichloroethylene (TCE) degradation using solar light was investigated. With both solar light and TiO2 present, TCE was more effectively degraded than either with solar light or TiO2 alone. The rate of photocatalytic degradation under a clear sky was about five and 18 times higher than that of photocatalytic degradation under cloudy and thick cloudy skies, respectively. The optimization of the degradation rates was strongly dependent on the solar light intensity. All experimental data were fit to a first-order rate equation. Summer showed faster degradation rate than winter. From the mass balance, this study showed that over 80% of chloride in clear and partly cloudy skies was mineralized from TCE degradation. PMID:12940492

  13. Use of gene probes to assess the impact and effectiveness of aerobic In situ bioremediation of TCE.

    SciTech Connect

    Hazen, Terry C.; Chakraborty, Romy; Fleming, James M.; Gregory, Ingrid R.; Bowman, John P.; Jimenez, Luis; Zhang, Dai; Pfiffner, Susan M.; Brockman, Fred J.; Sayler, Gary S.

    2009-03-01

    Gene probe hybridization was used to determine distribution and expression of co-metabolic genes at a contaminated site as it underwent in situ methanotrophic bioremediation of trichloroethylene (TCE). The bioremediation strategies tested consisted of a series of air, air:methane, and air:methane:nutrient pulses using a horizontal injection well. Sediment core samples (n=367) taken from 0 (surface)-43m depth were probed for genes coding for soluble methane monooxygenase (sMMO) and toluene dioxygenase (TOD), which are known to cometabolize TCE. The same samples were also probed for genes coding for methanol dehydrogenase (MDH) to access changes in methylotrophic bacterial populations. Hybridization results showed that the frequency of detection of sMMO genes were stimulated approximately 250% following 1% methane:air (v/v) injection. Subsequent 4% methane:air (v/v) injection resulted in an 85% decline probably due to nutrient limitations, since subsequent addition of nutrients (gaseous nitrogen and phosphorus) caused an increase in the frequency of detection of sMMO genes. Detection of TOD genes declined during the process becoming non-detectable by the final treatment. These patterns indicate methanotrophs displaced heterotrophs containing TOD genes. Active transcription of sMMO and TOD was evidenced by hybridization to mRNA. These analyses combined with studies showing the concomitant decline in TCE concentrations, increases in methanotroph viable counts, increased mineralization rates of TCE, and increases in chloride inventories provide multiple lines of evidence that TCE remediation was caused specifically by methanotrophs. This work suggests that sMMO genes are responsible for most, if not all, of the biodegradation of TCE observed. This study demonstrated that the use of nucleic acid analytical methods provided a gene specific assessment of the effects of in situ treatment technologies.

  14. Use of gene probes to assess the impact and effectiveness of aerobic in situ bioremediation of TCE

    SciTech Connect

    Hazen, Terry C.; Chakraborty, Romy; Fleming, James M.; Gregory, Ingrid R.; Bowman, John P.; Jimenez, Luis; Zhang, Dai; Pfiffner, Susan M.; Brockman, Fred J.; Sayler, Gary S.

    2009-03-15

    Gene probe hybridization was used to determine distribution and expression of co-metabolic genes at a contaminated site as it underwent in situ methanotrophic bioremediation of trichloroethylene (TCE). The bioremediation strategies tested included a series of air, air:methane, and air:methane:nutrient pulses of the test plot using horizontal injection wells. During the test period, the levels of TCE reduced drastically in almost all test samples. Sediment core samples (n = 367) taken from 0 m (surface)-43 m depth were probed for gene coding for methanotrophic soluble methane monooxygenase (sMMO) and heterotrophic toluene dioxygenase (TOD), which are known to co-metabolize TCE. The same sediment samples were also probed for genes coding for methanol dehydrogenase (MDH) (catalyzing the oxidation of methanol to formaldehyde) to assess specifically changes in methylotrophic bacterial populations in the site. Gene hybridization results showed that the frequency of detection of sMMO genes were stimulated approximately 250% following 1% methane:air (v/v) injection. Subsequent injection of 4% methane:air (v/v) resulted in an 85% decline probably due to nutrient limitations, since addition of nutrients (gaseous nitrogen and phosphorus) thereafter caused an increase in the frequency of detection of sMMO genes. Detection of TOD genes declined during the process, and eventually they were non-detectable by the final treatment, suggesting that methanotrophs displaced the TOD gene containing heterotrophs. Active transcription of sMMO and TOD was evidenced by hybridization to mRNA. These analyses combined with results showing the concomitant decline in TCE concentrations, increases in chloride concentration and increases in methanotroph viable counts, provide multiple lines of evidence that TCE remediation was caused specifically by methanotrophs. Our results suggest that sMMO genes are responsible for most, if not all, of the observed biodegradation of TCE. This study demonstrates that the use of nucleic acid analytical methods provided a gene specific assessment of the effects of in situ treatment technologies.

  15. The in-situ decontamination of sand and gravel aquifers by chemically enhanced solubilization of multiple-compound DNAPLs with surfactant solutions: Phase 1 -- Laboratory and pilot field-scale testing and Phase 2 -- Solubilization test and partitioning and interwell tracer tests. Final report

    SciTech Connect

    1997-10-24

    Laboratory, numerical simulation, and field studies have been conducted to assess the potential use of micellar-surfactant solutions to solubilize chlorinated solvents contaminating sand and gravel aquifers. Ninety-nine surfactants were screened for their ability to solubilize trichloroethene (TCE), perchloroethylene (PCE), and carbon tetrachloride (CTET). The field test was conducted in the alluvial aquifer which is located 20 to 30 meters beneath a vapor degreasing operation at Paducah Gaseous Diffusion Plant. This aquifer has become contaminated with TCE due to leakage of perhaps 40,000 liters of TCE, which has generated a plume of dissolved TCE extending throughout an area of approximately 3 km{sup 2} in the aquifer. Most of the TCE is believed to be present in the overlying lacustrine deposits and in the aquifer itself as a dense, non-aqueous phase liquid, or DNAPL. The objective of the field test was to assess the efficacy of the surfactant for in situ TCE solubilization. Although the test demonstrated that sorbitan monooleate was unsuitable as a solubilizer in this aquifer, the single-well test was demonstrated to be a viable method for the in situ testing of surfactants or cosolvents prior to proceeding to full-scale remediation.

  16. Anaerobic biotransformation of chlorinated aliphatic hydrocarbons: Ugly duckling to beautiful swan

    SciTech Connect

    Parkin, G.F.

    1999-10-01

    For many years anaerobic biological processes were reputed to be more sensitive than aerobic processes to toxic substances such as chlorinated aliphatic hydrocarbons (CAH) and thus a poor choice for treating water containing these compounds. This was especially true for water containing perchloroethylene (PCE) or trichloroethylene (TCE) because vinyl chloride, a human carcinogen, is produced when these two compounds are degraded anaerobically. Aerobic treatment with organisms containing oxygenase enzyme systems, which could fortuitously degrade a wide variety of chlorinated aliphatics (but not PCE), was favored. Recently, however, several enrichments and organisms have been isolated that will convert PCE and TCE into ethene and ethane, as shown by field data. Because of this evidence, anaerobic processes are now considered a significant alternative treatment for CAH contamination. Recent work at the University of Iowa, Iowa City, has focused on the effect of mixtures of CAHs on biotransformation of individual organic compounds and the potential for a combined methanogen-iron (Fe(0)) system to improve CAH bioremediation. At the concentration ranges tested, the presence of a mixture of CAHs seems to decrease rate of transformation of individual organics. However, there are important exceptions; in some cases a mixture of CAHs seems to facilitate transformation of an individual organic compound. Combination of an active methanogenic population with Fe(0) increases the rate and extent of transformation of carbon tetrachloride and chloroform. Results with PCE and 1,1,1-trichloroethane are less clear.

  17. Surfactant properties and tetrachloroethene (PCE) solubilisation ability of humic acid-like substances extracted from maize plant and from organic wastes: a comparative study.

    PubMed

    Adani, Fabrizio; Tambone, Fulvia; Davoli, Enrico; Scaglia, Barbara

    2010-02-01

    Humic acid-like substance (HA-like substance) extracted from maize plant residue at an yield of 81.1+/-4.9gkg(-1) of dry matter (dm) was tested for surfactant properties and ability to solubilise tetrachloroethene (PCE). Critical micelle concentration (CMC) of HA-like substance was detected to be 1986mgL(-1). Both, HA-like substance composition and average molecular weight [MW] affected CMC and a multiple linear regression model was proposed: CMC=12246-56.19 alkyl-C - 0.532MW (R(2)=0.90; P<0.01, n=7) where CMC was given in mgL(-1), alkyl-C was the percentage of total C, and MW was given in Da. Maize-HA-like substance solubilised PCE at the rate of 0.05g of PCE for each gram of maize-HA-like substance, which was 3.6-9.6 times lower than the data obtained in our earlier work using HA extracted from organic wastes, but was higher than that obtained with commercial HA from leonardite. Taking into consideration the two-site model of solubilisation of PCE in surfactant (i.e., solute partitioning into the micellar hydrophobic core and dissolution and/or binding into the hydrophilic non-ionic shell) and macromolecular composition of HA-like substance, the non-ionic hydrophile-alkyl lipophile balance was expected to control PCE solubilisation as the good multiple linear regression indicated: logK(dom)=-1.37+0.062 alkyl-C +0.055 O-alkyl-C (R(2)=0.93, P<0.05, n=6), where logK(dom) represents the micelle-water partitioning of PCE (mLg(-1)) and alkyl-C and O-alkyl-C represent the content of these two kinds of C detected by CP MAS (13)C NMR (as % of the total C). PMID:20044126

  18. Efficient Bayesian updating with PCE-based particle filters based on polynomial chaos expansion and CO2 storage

    NASA Astrophysics Data System (ADS)

    Oladyshkin, S.; Class, H.; Helmig, R.; Nowak, W.

    2011-12-01

    Underground flow systems, such as oil or gas reservoirs and CO2 storage sites, are an important and challenging class of complex dynamic systems. Lacking information about distributed systems properties (such as porosity, permeability,...) leads to model uncertainties up to a level where quantification of uncertainties may become the dominant question in application tasks. History matching to past production data becomes an extremely important issue in order to improve the confidence of prediction. The accuracy of history matching depends on the quality of the established physical model (including, e.g. seismic, geological and hydrodynamic characteristics, fluid properties etc). The history matching procedure itself is very time consuming from the computational point of view. Even one single forward deterministic simulation may require parallel high-performance computing. This fact makes a brute-force non-linear optimization approach not feasible, especially for large-scale simulations. We present a novel framework for history matching which takes into consideration the nonlinearity of the model and of inversion, and provides a cheap but highly accurate tool for reducing prediction uncertainty. We propose an advanced framework for history matching based on the polynomial chaos expansion (PCE). Our framework reduces complex reservoir models and consists of two main steps. In step one, the original model is projected onto a so-called integrative response surface via very recent PCE technique. This projection is totally non-intrusive (following a probabilistic collocation method) and optimally constructed for available reservoir data at the prior stage of Bayesian updating. The integrative response surface keeps the nonlinearity of the initial model at high order and incorporates all suitable parameters, such as uncertain parameters (porosity, permeability etc.) and design or control variables (injection rate, depth etc.). Technically, the computational costs for constructing the response surface depend on the number of parameters and the expansion degree. Step two consists of Bayesian updating in order to match the reduced model to available measurements of state variables or other past or real-time observations of system behavior (e.g. past production data or pressure at monitoring wells during a certain time period). In step 2 we apply particle filtering on the integrative response surface constructed at step one. Particle filtering is a strong technique for Bayesian updating which takes into consideration the nonlinearity of inverse problem in history matching more accurately than Ensemble Kalman filter do. Thanks to the computational efficiency of PCE and integrative response surface, Bayesian updating for history matching becomes an interactive task and can incorporate real time measurements.

  19. Metal mobility during in situ chemical oxidation of TCE by KMnO 4

    NASA Astrophysics Data System (ADS)

    Al, Tom A.; Banks, Vernon; Loomer, Diana; Parker, Beth L.; Ulrich Mayer, K.

    2006-11-01

    The potential for trace-metal contamination of aquifers as a side effect of In Situ Chemical Oxidation (ISCO) of chlorinated solvent contamination by KMnO 4 is investigated with column experiments. The experiments investigate metal mobility during in situ chemical oxidation of TCE by KMnO 4 under conditions where pH, flow rate, KMnO 4, TCE, and trace-metal concentrations were controlled. During ISCO, the injection of MnO 4 creates oxidizing conditions, and acidity released by the reactions causes a tendency toward low pH in aquifers. In order to evaluate the role of pH buffering on metal mobility, duplicate columns were constructed, one packed with pure silica sand, and one with a mixture of silica sand and calcite. Aqueous solutions of TCE and KMnO 4 (with 1 mg/L Cu, Pb, Zn, Mo, Ni, and Cr(VI)) were allowed to mix at the inlet to the columns. After the completion of the experiments, samples of Mn oxide were removed from the columns and analyzed by analytical scanning and transmission electron microscopy. In order to relate the results of the laboratory experiments to field settings, the analyses of Mn-oxide samples from the lab experiments were compared to samples of Mn oxide collected from a field-scale chemical-oxidation experiment that were also analyzed by analytical electron microscopy as well as time-of-flight secondary-ion mass spectroscopy. The pH ranged from 2.40 in the silica sand column to 6.25 in the calcite-containing column. The data indicate that aqueous Mo, Pb, Cu and Ni concentrations are attenuated almost completely within the columns. In contrast, Zn concentrations are not significantly attenuated and Cr(VI) is transported conservatively. The results indicate that within the range 2.40 to 6.25, metal mobility is not affected by pH. Comparison of analyses of Mn-oxide from the lab and field demonstrate that a variety of metals are sequestered from solution by Mn oxide.

  20. Public health assessment for Grand Traverse Overall Supply Company, Greilickville, Leelanau County, Michigan, Region 5. Cerclis No. MID017418559. Final report

    SciTech Connect

    Not Available

    1994-01-21

    The United States Environmental Protection Agency (U.S. EPA) placed the Grand Traverse Overall Supply site on the National Priorities List (NPL) on September 8, 1983. From 1953 through 1977, GTOS disposed of waste water from the process in a dry well and four lagoons on their property. Since 1977, they have used the township sewer system. In 1978, tetrachloroethylene (also known as perchloroethylene or PCE) and trichloroethylene (TCE) were found in the water in wells serving a school adjacent to GTOS and several nearby residences. The soil around the dry well was excavated and taken off-site for disposal. The lagoons were filled in, and covered with gravel or grass. The site currently poses no apparent public health hazard. Trace amounts of PCE in well water have been detected in the most recent testing, however, the amounts are below the level of public health concern.

  1. Effects of pyrolysis temperature on soybean stover- and peanut shell-derived biochar properties and TCE adsorption in water.

    PubMed

    Ahmad, Mahtab; Lee, Sang Soo; Dou, Xiaomin; Mohan, Dinesh; Sung, Jwa-Kyung; Yang, Jae E; Ok, Yong Sik

    2012-08-01

    Conversion of crop residues into biochars (BCs) via pyrolysis is beneficial to environment compared to their direct combustion in agricultural field. Biochars developed from soybean stover at 300 and 700 °C (S-BC300 and S-BC700, respectively) and peanut shells at 300 and 700 °C (P-BC300 and P-BC700, respectively) were used for the removal of trichloroethylene (TCE) from water. Batch adsorption experiments showed that the TCE adsorption was strongly dependent on the BCs properties. Linear relationships were obtained between sorption parameters (K(M) and S(M)) and molar elemental ratios as well as surface area of the BCs. The high adsorption capacity of BCs produced at 700 °C was attributed to their high aromaticity and low polarity. The efficacy of S-BC700 and P-BC700 for removing TCE from water was comparable to that of activated carbon (AC). Pyrolysis temperature influencing the BC properties was a critical factor to assess the removal efficiency of TCE from water. PMID:22721877

  2. Abiotic Removal of TCE and cis-DCE by Magnetite under Aerobic Conditions in Ground Water (Maryland)

    EPA Science Inventory

    The former Twin Cities Army Ammunition Plant (TCAAP) is located just north of St. Paul, Minnesota. Disposal of chlorinated solvents at the Building102 site on the TCAAP contaminated groundwater in the shallow, unconsolidated sand aquifer with TCE and cis-DCE. Concentrations of ...

  3. Abiotic and Biotic Transformation of TCE under Sulfate Reducing Conditions: the Role of Spatial Heterogeneity (Monterey, CA)

    EPA Science Inventory

    At a number of sites in the USA, passive reactive barriers built with shredded plant mulch have been constructed to treat ground water contaminated with TCE. These barriers are called biowalls because anaerobic biodegradation of the plant mulch is expected to provide substrates ...

  4. Application of fluorescent antibody and enzyme-linked immunosorbent assays for TCE and PAH degrading bacteria

    SciTech Connect

    Brigmon, R.L.; Franck, M.; Brey, J.; Scott, D.; Lanclos, K.; Fliermans, C.

    1996-07-01

    Historically, methods used to identify methanotrophic and polyaromatic hydrocarbon-degrading (PAH) bacteria in environmental samples have been inadequate because isolation and identification procedures are time-consuming and often fail to separate specific bacteria from other environmental microorganisms. Methanotrophic bacteria have been isolated and characterized from TCE-contaminated soils (Bowman et al. 1993; Fliermans et al., 1988). Fliermans et al., (1988) and others demonstrated that cultures enriched with methane and propane could cometabolically degrade a wide variety of chlorinated aliphatic hydrocarbons including ethylene; 1,2-cisdichloroethylene (c-DCE); 1,2-trans-dichloroethylene (t-DCE); vinyl chloride (VC); toluene; phenol and cresol. Characterization of select microorganisms in the natural setting is important for the evaluation of bioremediation potential and its effectiveness. This realization has necessitated techniques that are selective, sensitive and easily applicable to soils, sediments, and groundwater (Fliermans, et al., 1994). Additionally these techniques can identify and quantify microbial types in situ in real time

  5. Development of an updated PBPK model for trichloroethylene and metabolites in mice, and its application to discern the role of oxidative metabolism in TCE-induced hepatomegaly

    SciTech Connect

    Evans, M.V. Chiu, W.A.; Okino, M.S.; Caldwell, J.C.

    2009-05-01

    Trichloroethylene (TCE) is a lipophilic solvent rapidly absorbed and metabolized via oxidation and conjugation to a variety of metabolites that cause toxicity to several internal targets. Increases in liver weight (hepatomegaly) have been reported to occur quickly in rodents after TCE exposure, with liver tumor induction reported in mice after long-term exposure. An integrated dataset for gavage and inhalation TCE exposure and oral data for exposure to two of its oxidative metabolites (TCA and DCA) was used, in combination with an updated and more accurate physiologically-based pharmacokinetic (PBPK) model, to examine the question as to whether the presence of TCA in the liver is responsible for TCE-induced hepatomegaly in mice. The updated PBPK model was used to help discern the quantitative contribution of metabolites to this effect. The update of the model was based on a detailed evaluation of predictions from previously published models and additional preliminary analyses based on gas uptake inhalation data in mice. The parameters of the updated model were calibrated using Bayesian methods with an expanded pharmacokinetic database consisting of oral, inhalation, and iv studies of TCE administration as well as studies of TCE metabolites in mice. The dose-response relationships for hepatomegaly derived from the multi-study database showed that the proportionality of dose to response for TCE- and DCA-induced hepatomegaly is not observed for administered doses of TCA in the studied range. The updated PBPK model was used to make a quantitative comparison of internal dose of metabolized and administered TCA. While the internal dose of TCA predicted by modeling of TCE exposure (i.e., mg TCA/kg-d) showed a linear relationship with hepatomegaly, the slope of the relationship was much greater than that for directly administered TCA. Thus, the degree of hepatomegaly induced per unit of TCA produced through TCE oxidation is greater than that expected per unit of TCA administered directly, which is inconsistent with the hypothesis that TCA alone accounts for TCE-induced hepatomegaly. In addition, TCE-induced hepatomegaly showed a much more consistent relationship with PBPK model predictions of total oxidative metabolism than with predictions of TCE area-under-the-curve in blood, consistent with toxicity being induced by oxidative metabolites rather than the parent compound. Therefore, these results strongly suggest that oxidative metabolites in addition to TCA are necessary contributors to TCE-induced liver weight changes in mice.

  6. Analysis of sources of bulk conductivity change in saturated silica sand after unbuffered TCE oxidation by permanganate

    NASA Astrophysics Data System (ADS)

    Hort, Ryan D.; Revil, André; Munakata-Marr, Junko

    2014-09-01

    Time lapse resistivity surveys could potentially improve monitoring of permanganate-based in situ chemical oxidation (ISCO) of organic contaminants such as trichloroethene (TCE) by tracking changes in subsurface conductivity that result from injection of permanganate and oxidation of the contaminant. Bulk conductivity and pore fluid conductivity changes during unbuffered TCE oxidation using permanganate are examined through laboratory measurements and conductivity modeling using PHREEQC in fluid samples and porous media samples containing silica sand. In fluid samples, oxidation of one TCE molecule produces three chloride ions and one proton, resulting in an increase in fluid electrical conductivity despite the loss of two permanganate ions in the reaction. However, in saturated sand samples in which up to 8 mM TCE was oxidized, at least 94% of the fluid conductivity associated with the presence of protons was removed within 3 h of sand contact, most likely through protonation of silanol groups found on the surface of the sand grains. Minor conductivity effects most likely associated with pH-dependent reductive dissolution of manganese dioxide were also observed but not accounted for in pore-fluid conductivity modeling. Unaccounted conductivity effects resulted in an under-calculation of post-reaction pore fluid conductivity of 2.1% to 5.5%. Although small increases in the porous media formation factor resulting from precipitation of manganese dioxide were detected (about 3%), these increases could not be confirmed to be statistically significant. Both injection of permanganate and oxidation of TCE cause increases in bulk conductivity that would be detectable through time-lapse resistivity surveys in field conditions.

  7. Adverse Birth Outcomes and Maternal Exposure to Trichloroethylene and Tetrachloroethylene through Soil Vapor Intrusion in New York State

    PubMed Central

    Lewis-Michl, Elizabeth L.; Gomez, Marta I.

    2011-01-01

    Background: Industrial spills of volatile organic compounds (VOCs) in Endicott, New York (USA), have led to contamination of groundwater, soil, and soil gas. Previous studies have reported an increase in adverse birth outcomes among women exposed to VOCs in drinking water. Objective: We investigated the prevalence of adverse birth outcomes among mothers exposed to trichloroethylene (TCE) and tetrachloroethylene [or perchloroethylene (PCE)] in indoor air contaminated through soil vapor intrusion. Methods: We examined low birth weight (LBW), preterm birth, fetal growth restriction, and birth defects among births to women in Endicott who were exposed to VOCs, compared with births statewide. We used Poisson regression to analyze births and malformations to estimate the association between maternal exposure to VOCs adjusting for sex, mother’s age, race, education, parity, and prenatal care. Two exposure areas were identified based on environmental sampling data: one area was primarily contaminated with TCE, and the other with PCE. Results: In the TCE-contaminated area, adjusted rate ratios (RRs) were significantly elevated for LBW [RR = 1.36; 95% confidence interval (CI): 1.07, 1.73; n = 76], small for gestational age (RR = 1.23; 95% CI: 1.03, 1.48; n = 117), term LBW (RR = 1.68; 95% CI: 1.20, 2.34; n = 37), cardiac defects (RR = 2.15; 95% CI: 1.27, 3.62; n = 15), and conotruncal defects (RR = 4.91; 95% CI: 1.58, 15.24; n = 3). In the PCE-contaminated area, RRs for cardiac defects (five births) were elevated but not significantly. Residual socioeconomic confounding may have contributed to elevations of LBW outcomes. Conclusions: Maternal residence in both areas was associated with cardiac defects. Residence in the TCE area, but not the PCE area, was associated with LBW and fetal growth restriction. PMID:22142966

  8. Electrochemical deposition of green rust on zero-valent iron 

    E-print Network

    Kulkarni, Dhananjay Vijay

    2006-08-16

    Perchloroethylene (PCE) is a toxic contaminant that has been introduced into the environment over many years through industrial and agricultural wastes. Research has been done in the past to investigate PCE degradation by ...

  9. Acute Exposure to Perchlorethylene alters Rat Visual Evoked Potentials in Relation to Brain Concentration

    EPA Science Inventory

    These experiments sought to establish a dose-effect relationship between the concentration of perchloroethylene (PCE) in brain tissue and concurrent changes in visual function. A physiologically-based pharmacokinetic (PBPK) model was implemented to predict concentrations of PCE ...

  10. Affinity for risky behaviors following prenatal and early childhood exposure to tetrachloroethylene (PCE)-contaminated drinking water: a retrospective cohort study

    PubMed Central

    2011-01-01

    Background Many studies of adults with acute and chronic solvent exposure have shown adverse effects on cognition, behavior and mood. No prior study has investigated the long-term impact of prenatal and early childhood exposure to the solvent tetrachloroethylene (PCE) on the affinity for risky behaviors, defined as smoking, drinking or drug use as a teen or adult. Objectives This retrospective cohort study examined whether early life exposure to PCE-contaminated drinking water influenced the occurrence of cigarette smoking, alcohol consumption, and drug use among adults from Cape Cod, Massachusetts. Methods Eight hundred and thirty-one subjects with prenatal and early childhood PCE exposure and 547 unexposed subjects were studied. Participants completed questionnaires to gather information on risky behaviors as a teenager and young adult, demographic characteristics, other sources of solvent exposure, and residences from birth through 1990. PCE exposure was estimated using the U.S. EPA's water distribution system modeling software (EPANET) that was modified to incorporate a leaching and transport model to estimate PCE exposures from pipe linings. Results Individuals who were highly exposed to PCE-contaminated drinking water during gestation and early childhood experienced 50-60% increases in the risk of using two or more major illicit drugs as a teenager or as an adult (Relative Risk (RR) for teen use = 1.6, 95% CI: 1.2-2.2; and RR for adult use = 1.5, 95% CI: 1.2-1.9). Specific drugs for which increased risks were observed included crack/cocaine, psychedelics/hallucinogens, club/designer drugs, Ritalin without a prescription, and heroin (RRs:1.4-2.1). Thirty to 60% increases in the risk of certain smoking and drinking behaviors were also seen among highly exposed subjects. Conclusions The results of this study suggest that risky behaviors, particularly drug use, are more frequent among adults with high PCE exposure levels during gestation and early childhood. These findings should be confirmed in follow-up investigations of other exposed populations. PMID:22136431

  11. Anaerobic dechlorination and redox activities after full-scale Electrical Resistance Heating (ERH) of a TCE-contaminated aquifer

    NASA Astrophysics Data System (ADS)

    Friis, A. K.; Heron, G.; Albrechtsen, H.-J.; Udell, K. S.; Bjerg, P. L.

    2006-12-01

    The effects of Electrical Resistance Heating (ERH) on dechlorination of TCE and redox conditions were investigated in this study. Aquifer and groundwater samples were collected prior to and after ERH treatment, where sediments were heated to approximately 100 °C. Sediment samples were collected from three locations and examined in microcosms for 250 to 400 days of incubation. Redox activities, in terms of consumed electron acceptors, were low in unamended microcosms with field-heated sediments, although they increased upon lactate-amendment. TCE was not dechlorinated or stalled at cDCE with field-heated sediments, which was similar or lower compared to the degree of dechlorination in unheated microcosms. However, in microcosms which were bioaugmented with a mixed anaerobic dechlorinating culture (KB-1™) and lactate, dechlorination past cDCE to ethene was observed in field-heated sediments. Dechlorination and redox activities in microcosms with field-heated sediments were furthermore compared with controlled laboratory-heated microcosms, which were heated to 100 °C for 10 days and then slowly cooled to 10 °C. In laboratory-heated microcosms, TCE was not dechlorinated and redox activities remained low in unamended and lactate-amended sediments, although organic carbon was released to the aqueous phase. In contrast, in field-heated sediments, high aqueous concentrations of organic carbon were not observed in unamended microcosms, and TCE was dechlorinated to cDCE upon lactate amendment. This suggests that dechlorinating microorganisms survived the ERH or that groundwater flow through field-heated sediments carried microorganisms into the treated area and transported dissolved organic carbon downstream.

  12. CuSCN-Based Inverted Planar Perovskite Solar Cell with an Average PCE of 15.6%.

    PubMed

    Ye, Senyun; Sun, Weihai; Li, Yunlong; Yan, Weibo; Peng, Haitao; Bian, Zuqiang; Liu, Zhiwei; Huang, Chunhui

    2015-06-10

    Although inorganic hole-transport materials usually possess high chemical stability, hole mobility, and low cost, the efficiency of most of inorganic hole conductor-based perovskite solar cells is still much lower than that of the traditional organic hole conductor-based cells. Here, we have successfully fabricated high quality CH3NH3PbI3 films on top of a CuSCN layer by utilizing a one-step fast deposition-crystallization method, which have lower surface roughness and smaller interface contact resistance between the perovskite layer and the selective contacts in comparison with the films prepared by a conventional two-step sequential deposition process. The average efficiency of the CuSCN-based inverted planar CH3NH3PbI3 solar cells has been improved to 15.6% with a highest PCE of 16.6%, which is comparable to that of the traditional organic hole conductor-based cells, and may promote wider application of the inexpensive inorganic materials in perovskite solar cells. PMID:25938881

  13. Field performance of air-sparging system for removing TCE from groundwater

    SciTech Connect

    Rabideau, A.J.; Blayden, J.M.; Ganguly, C.

    1999-01-01

    The removal of volatile organic compounds from groundwater by air sparging (AS) is well-established, although reliable methods for predicting the time required to reach site closure have not been established. To develop and improved understanding of mass transfer processes that limit AS performance, two extended controlled shutdowns of an operating AS system were performed. Monitoring of TCE concentrations in source zone groundwater indicated tailing and rebound behavior similar to that observed for pump-and-treat systems. A simple two-compartment model provided a reasonable description of the 3-year AS history, using parameters calibrated from data collected during the first shutdown period. Comparison of the calibrated rate constants with parameters estimated from laboratory soil columns suggest that, for the study site, aqueous diffusion to discrete air channels has a stronger influence on system performance than rate-limited desorption. Predictions based on the calibrated model indicated that restoration of the source zone to drinking water standards would require approximately 1 decade for the current AS system.

  14. Analysis of flow processes during TCE infiltration in heterogeneous soils at the Savannah River Site, Aiken, South Carolina

    SciTech Connect

    Pruess, K.

    1992-06-01

    Contamination of soils and groundwater from volatile organic compounds (VOCs), such as organic solvents and hydrocarbon fuels, is a problem at many industrial facilities. Key to successfully characterizing, containing, and eventually remediating the contamination is a thorough understanding, based on sound scientific principles, of the complex interplay of physical, chemical, and biological processes in geologic media, which affect the migration and distribution of the contaminants, and their response to remediation operations. This report focusses on physical mechanisms that affect contaminant behavior under the conditions encountered at the Savannah River site (SRS). Although other contaminants are present at the site, for the purpose of this discussion we will restrict ourselves to the processes following a spill and infiltration of trichloroethylene (TCE), which is the main contaminant at the location of the Integrated Demonstration Project. We begin by briefly describing the main physical processes following release of TCE into the subsurface. Subsequently we will present simple engineering models that can help to evaluate contaminant migration processes in a semi-quantitative way. Finally, we will discuss results of detailed numerical simulations of TCE infiltration into a heterogeneous medium consisting of sands and clays. These simulations attempt to shed light on the initial distribution of contaminants at the site prior to the start of remediation operations. We also point out limitations of present numerical modeling capabilities, and identify issues that require further research in order that a realistic description of contaminant behavior in the subsurface may be achieved.

  15. Heterogeneous carbonaceous matter in sedimentary rock lithocomponents causes significant trichloroethylene (TCE) sorption in a low organic carbon content aquifer/aquitard system

    NASA Astrophysics Data System (ADS)

    Choung, Sungwook; Zimmerman, Lisa R.; Allen-King, Richelle M.; Ligouis, Bertrand; Feenstra, Stanley

    2014-10-01

    This study evaluated the effects of heterogeneous thermally altered carbonaceous matter (CM) on trichloroethylene (TCE) sorption for a low fraction organic carbon content (foc) alluvial sedimentary aquifer and aquitard system (foc = 0.046-0.105%). The equilibrium TCE sorption isotherms were highly nonlinear with Freundlich exponents of 0.46-0.58. Kerogen + black carbon was the dominant CM fraction extracted from the sediments and accounted for > 60% and 99% of the total in the sands and silt, respectively. Organic petrological examination determined that the kerogen included abundant amorphous organic matter (bituminite), likely of marine origin. The dark calcareous siltstone exhibited the greatest TCE sorption among aquifer lithocomponents and accounted for most sorption in the aquifer. The results suggest that the source of the thermally altered CM, which causes nonlinear sorption, was derived from parent Paleozoic marine carbonate rocks that outcrop throughout much of New York State. A synthetic aquifer-aquitard unit system (10% aquitard) was used to illustrate the effect of the observed nonlinear sorption on mass storage potential at equilibrium. The calculation showed that > 80% of TCE mass contained in the aquifer was sorbed on the aquifer sediment at aqueous concentration < 1000 ?g L- 1. These results show that sorption is likely a significant contributor to the persistence of a TCE groundwater plume in the aquifer studied. It is implied that sorption may similarly contribute to TCE persistence in other glacial alluvial aquifers with similar geologic characteristics, i.e., comprised of sedimentary rock lithocomponents that contain thermally altered CM.

  16. Superfund Record of Decision (EPA Region 5): Charlevoix Site, Michigan (second remedial action), September 1985. Final report

    SciTech Connect

    Not Available

    1985-09-30

    The City of Charlevoix is located on the shores of Lake Michigan in Charlevoix County. The City's single municipal well supplies potable water to a year-round population of 3500 which increases to approximately 5,000 during the summer tourist season. In September 1981, while conducting tests for trihalogenated methane compounds, the Michigan Department of Public Health (MDPH) detected trichloroethylene (TCE) ranging in concentrations from 13 to 30 ppb in the Charlevoix water supply. Data from the monitoring program showed gradually rising levels of TCE and perchloroethylene (PCE) in the raw water. In June 1984, a Record of Decision was signed which approved an initial remedial measure (IRM) for an alternative water supply to replace the contaminated municipal well. The selected IRM consisted of a Lake Michigan water intake structure and a water filtration/flocculation treatment plant. The selected remedial action involves discharging the TCE and PCE plumes, under natural flow conditions, to Lake Michigan. The aquifer would be useable after 50 years. During that 50-year purging period, institutional restrictions on the installation of private wells in the contaminated aquifer will be enforced by local health officials. In addition, long-term monitoring of the plumes will continue. The estimated annual OandM costs for monitoring are $17,000.

  17. Using trees to remediate groundwaters contaminated with chlorinated hydrocarbons. 1997 annual progress report

    SciTech Connect

    Gordon, M.P.; Newman, L.A.; Strand, S.E.

    1997-01-01

    'Metabolism of Chlorinated Hydrocarbons Laboratory and field tests with poplar in tissue culture, bioreactors, and field sites have shown that, unlike bacteria, these plants are able to carry out complete degradation of fully chlorinated alkanes and alkenes to carbon dioxide and chloride. Carbon dioxide was produced as a product of the degradation of trichloroethylene (TCE), carbon tetrachloride (CT), and perchloroethylene (PCE) when axenic tissue cultures of poplar cells were exposed to radiolabelled compounds. The apparent degradation of PCE and CT, fully chlorinated hydrocarbons, in these aerobic plants is remarkable when contrasted to the lack of comparable aerobic degradation by bacteria. Oxidized metabolites, such as trichloroethanol, and di- and trichloroacetic acid, were detected in cell cultures exposed to TCE, suggesting the involvement of cytochrome P450s or other monooxygenase activities. Mass balance experiments with small poplar plants in laboratory reactors showed that significant TCE and CT was volatilized from the leaves, while a similar fraction of radiolabeled carbon from these chlorinated solvents was retained in the plant tissue.'

  18. Biobased surfactant-like molecules from organic wastes: the effect of waste composition and composting process on surfactant properties and on the ability to solubilize Tetrachloroethene (PCE).

    PubMed

    Quadri, Giorgia; Chen, Xiaosong; Jawitz, James W; Tambone, Fulvia; Genevini, Pierluigi; Faoro, Franco; Adani, Fabrizio

    2008-04-01

    In this work, four surfactant-like humic acids (HAs) obtained from garden lignocellulose wastes and kitchen food wastes mixed with garden-lignocellulose wastes, both before and after composting, were tested for surfactant properties and the ability to solubilize tetrachloroethene (PCE). The waste-derived HAs showed good surfactant properties, lowering the water surface tension from 74 mN m(-1) to 45.4 +/- 4.4 mN m(-1), with a critical micelle concentration (CMC) of 1.54 +/- 1.68 g L(-1), which is lower than many synthetic ionic surfactants. CMC was affected by both waste origin and composting processes. The addition of food waste and composting reduced CMC by adding alkyl-C (measured by CP MAS 13C NMR) and N- and S-HA contents (amide molecules), so that a multistep regression was found [CMC = 24.6 - 0.189 alkyl C - 2.64 (N + S); R2 = 0.77, P < 0.10, n = 6]. The four HAs solubilized PCE at the rate of 0.18-0.47 g PCE/g aqueous biosurfactant. These results were much higher than those reported in the literature for a commercial HA (0.026 g/g), but they were in line with those measured in this work for nonionic surfactants such as Tween-80 (0.69 g/g) and Triton X-100 (1.08 g/g). PMID:18505006

  19. Structural Magnetic Resonance Imaging in an adult cohort following prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water.

    PubMed

    Janulewicz, Patricia A; Killiany, Ronald J; White, Roberta F; Martin, Brett M; Winter, Michael R; Weinberg, Janice M; Aschengrau, Ann

    2013-01-01

    This population-based retrospective cohort study examined Structural Magnetic Resonance Imaging (MRI) of the brain in relation to prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using pipe network information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and Geographic Information System (GIS) methodology. Brain imaging was performed on 26 exposed and 16 unexposed subjects. Scans were acquired on a Philips 3T whole body scanner using the ADNI T1-weighted MP-RAGE scan. The scans were processed by FreeSurfer version 4.3.1 software to obtain measurements of specific brain regions. There were no statistically significant differences between exposed and unexposed subjects on the measures of white matter hypointensities (?: 127.5mm(3), 95% CI: -259.1, 1514.0), white matter volumes (e.g. total cerebral white matter: ?: 21230.0mm(3), 95% CI: -4512.6, 46971.7) or gray matter volumes (e.g. total cerebral gray matter: ?: 11976.0mm(3), 95% CI: -13657.2, 37609.3). The results of this study suggest that exposure to PCE during gestation and early childhood, at the levels observed in this population, is not associated with alterations in the brain structures studied. PMID:23571160

  20. Structural Magnetic Resonance Imaging in an Adult Cohort Following Prenatal and Early Postnatal Exposure to Tetrachloroethylene (PCE)-contaminated Drinking Water

    PubMed Central

    Janulewicz, Patricia A; Killiany, Ronald J; White, Roberta F; Martin, Brett M; Winter, Michael R; Weinberg, Janice M; Aschengrau, Ann

    2013-01-01

    This population-based retrospective cohort study examined Structural Magnetic Resonance Imaging (MRI) of the brain in relation to prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using pipe network information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and Geographic Information System (GIS) methodology. Brain imaging was performed on 26 exposed and 16 unexposed subjects. Scans were acquired on a Philips 3T whole body scanner using the ADNI T1-weighted MP-RAGE scan. The scans were processed by FreeSurfer version 4.3.1 software to obtain measurements of specific brain regions. There were no statistically significant differences between exposed and unexposed subjects on measures of white matter hypointensities (?: 127.5 mm3, 95% CI: ?259.1, 1514.0), white matter volumes (e.g. total cerebral white matter: ?: 21230.0 mm3, 95% CI: ?4512.6, 46971.7) or gray matter volumes (e.g. total cerebral gray matter: ?: 11976.0 mm3, 95% CI: ?13657.2, 37609.3). The results of this study suggest that exposure to PCE during gestation and early childhood, at the levels observed in this population, is not associated with alterations in the brain structures studied. PMID:23571160

  1. Heterogeneous hyporheic zone dechlorination of a TCE groundwater plume discharging to an urban river reach.

    PubMed

    Freitas, Juliana G; Rivett, Michael O; Roche, Rachel S; Durrant Neé Cleverly, Megan; Walker, Caroline; Tellam, John H

    2015-02-01

    The typically elevated natural attenuation capacity of riverbed-hyporheic zones is expected to decrease chlorinated hydrocarbon (CHC) groundwater plume discharges to river receptors through dechlorination reactions. The aim of this study was to assess physico-chemical processes controlling field-scale variation in riverbed-hyporheic zone dechlorination of a TCE groundwater plume discharge to an urban river reach. The 50-m long pool-riffle-glide reach of the River Tame in Birmingham (UK) studied is a heterogeneous high energy river environment. The shallow riverbed was instrumented with a detailed network of multilevel samplers. Freeze coring revealed a geologically heterogeneous and poorly sorted riverbed. A chlorine number reduction approach provided a quantitative indicator of CHC dechlorination. Three sub-reaches of contrasting behaviour were identified. Greatest dechlorination occurred in the riffle sub-reach that was characterised by hyporheic zone flows, moderate sulphate concentrations and pH, anaerobic conditions, low iron, but elevated manganese concentrations with evidence of sulphate reduction. Transient hyporheic zone flows allowing input to varying riverbed depths of organic matter are anticipated to be a key control. The glide sub-reach displayed negligible dechlorination attributed to the predominant groundwater baseflow discharge condition, absence of hyporheic zone, transition to more oxic conditions and elevated sulphate concentrations expected to locally inhibit dechlorination. The tail-of-pool-riffle sub-reach exhibited patchy dechlorination that was attributed to sub-reach complexities including significant flow bypass of a low permeability, high organic matter, silty unit of high dechlorination potential. A process-based conceptual model of reach-scale dechlorination variability was developed. Key findings of practitioner relevance were: riverbed-hyporheic zone CHC dechlorination may provide only a partial, somewhat patchy barrier to CHC groundwater plume discharges to a surface water receptor; and, monitoring requirements to assess the variability in CHC attenuation within a reach are expected to be onerous. Further research on transient hyporheic zone dechlorination is recommended. PMID:25461025

  2. Comparison Of A Laboratory Consortium That Dechlorinates TCE To Ethene To The Field Community From Which It Was Derived

    SciTech Connect

    T. Wood; K. S. Sorenson; D. E. Cummings

    2004-12-01

    Sodium lactate additions to a trichloroethene (TCE) residual source area in deep, fractured basalt at a U.S. Department of Energy site have resulted in the enrichment of the indigenous microbial community, the complete dechlorination of nearly all aqueous-phase TCE to ethene, and the continued depletion of the residual source since 1999. The bacterial and archaeal consortia in groundwater obtained from the residual source were assessed by using PCR-amplified 16S rRNA genes. A clone library of bacterial amplicons was predominated by those from members of the class Clostridia (57 of 93 clones), of which a phylotype most similar to that of the homoacetogen Acetobacterium sp. strain HAAP-1 was most abundant (32 of 93 clones). The remaining Bacteria consisted of phylotypes affiliated with Sphingobacteria, Bacteroides, Spirochaetes, Mollicutes, and Proteobacteria and candidate divisions OP11 and OP3. The two proteobacterial phylotypes were most similar to those of the known dechlorinators Trichlorobacter thiogenes and Sulfurospirillum multivorans. Although not represented by the bacterial clones generated with broad-specificity bacterial primers, a Dehalococcoides-like phylotype was identified with genus-specific primers. Only four distinct phylotypes were detected in the groundwater archaeal library, including predominantly a clone affiliated with the strictly acetoclastic methanogen Methanosaeta concilii (24 of 43 clones). A mixed culture that completely dechlorinates TCE to ethene was enriched from this groundwater, and both communities were characterized by terminal restriction fragment length polymorphism (T-RFLP). According to T-RFLP, the laboratory enrichment community was less diverse overall than the groundwater community, with 22 unique phylotypes as opposed to 43 and a higher percentage of Clostridia, including the Acetobacterium population. Bioreactor archaeal structure was very similar to that of the groundwater community, suggesting that methane is generated primarily via the acetoclastic pathway, using acetate generated by lactate fermentation and acetogenesis in both systems.

  3. A Dechlorinating Community Resulting From In Situ Biostimulation of a TCE-contaminated Deep Fracture Basalt Aquifer

    SciTech Connect

    T. Wood; D. E. Cummings

    2004-12-01

    Sodium lactate additions to a trichloroethene (TCE) residual source area in deep, fractured basalt at a U.S. Department of Energy site have resulted in the enrichment of the indigenous microbial community, the complete dechlorination of nearly all aqueous-phase TCE to ethene, and the continued depletion of the residual source since 1999. The bacterial and archaeal consortia in groundwater obtained from the residual source were assessed by using PCR-amplified 16S rRNA genes. A clone library of bacterial amplicons was predominated by those from members of the class Clostridia (57 of 93 clones), of which a phylotype most similar to that of the homoacetogen Acetobacterium sp. strain HAAP-1 was most abundant (32 of 93 clones). The remaining Bacteria consisted of phylotypes affiliated with Sphingobacteria, Bacteroides, Spirochaetes, Mollicutes, and Proteobacteria and candidate divisions OP11 and OP3. The two proteobacterial phylotypes were most similar to those of the known dechlorinators Trichlorobacter thiogenes and Sulfurospirillum multivorans. Although not represented by the bacterial clones generated with broad-specificity bacterial primers, a Dehalococcoides-like phylotype was identified with genus-specific primers. Only four distinct phylotypes were detected in the groundwater archaeal library, including predominantly a clone affiliated with the strictly acetoclastic methanogen Methanosaeta concilii (24 of 43 clones). A mixed culture that completely dechlorinates TCE to ethene was enriched from this groundwater, and both communities were characterized by terminal restriction fragment length polymorphism (T-RFLP). According to T-RFLP, the laboratory enrichment community was less diverse overall than the groundwater community, with 22 unique phylotypes as opposed to 43 and a higher percentage of Clostridia, including the Acetobacterium population. Bioreactor archaeal structure was very similar to that of the groundwater community, suggesting that methane is generated primarily via the acetoclastic pathway, using acetate generated by lactate fermentation and acetogenesis in both systems.

  4. The impact of additives found in industrial formulations of TCE on the wettability of sandstone

    NASA Astrophysics Data System (ADS)

    Harrold, Gavin; Lerner, David N.; Leharne, Stephen A.

    2005-11-01

    The wettability of aquifer rocks is a key physical parameter which exerts an important control on the transport, residual trapping, distribution and eventual fate of chlorinated hydrocarbon solvents (CHSs) released into the subsurface. Typically chlorinated solvents are assumed to be non-wetting in water saturated rocks and unconsolidated sediments. However industrially formulated solvent products are often combined with basic additives such as alkylamines to improve their performance; and the mineral surfaces of aquifer rocks and sediments usually possess a range of acid and hydrogen-bonding adsorption sites. The presence of these sites provides a mechanism whereby the basic additives in CHSs can be adsorbed at the solvent phase/solid phase interface. Given the amphiphilic molecular structure of these additives, this may result in changes in the wetting conditions of the solid phase. The aim of this study was therefore to test this conjecture for two classes of additives (alkylamines and quaternary ammonium salts) that are often encountered in industrial solvent formulations. Wettability assessments were made on sandstone cores by means of measurements of spontaneous and forced water drainage and spontaneous and forced water imbibition and through contact angle measurements on a smooth quartz surface. No solvent/additive combination produced solvent wetting conditions, though dodecylamine and octadecylamine significantly reduced the water wetting preference of sandstone which frequently resulted in neutral wetting conditions. The large volume of spontaneous water drainage observed in wettability experiments involving cetyltrimethylammonium bromide and octadecyltrimethylammonium bromide, suggested that the sandstone cores in these tests remained strongly water wetting. However equilibrium static contact angles of around 60° were measured on quartz suggesting that the sandstone surfaces should be close to neutral wetting conditions. This paradox was finally resolved by noting that contact between the solvent mixture and water in the sandstone core resulted in a final solvent phase which had an extremely low interfacial tension. It is therefore suspected that the observed spontaneous drainage of solvent from the core was driven by gravitational and buoyancy forces rather than strong water wetting conditions. Finally it was noted that the mobilisation of iron oxide coatings from the sandstone surface had a considerable influence in reducing the interfacial tension and in the formation and stabilisation of TCE/water emulsions.

  5. Effect of toluene concentration and hydrogen peroxide on Pseudomonas plecoglossicida cometabolizing mixture of cis-DCE and TCE in soil slurry.

    PubMed

    Li, Junhui; Lu, Qihong; de Toledo, Renata Alves; Lu, Ying; Shim, Hojae

    2015-12-01

    An indigenous Pseudomonas sp., isolated from the regional contaminated soil and identified as P. plecoglossicida, was evaluated for its aerobic cometabolic removal of cis-1,2-dichloroethylene (cis-DCE) and trichloroethylene (TCE) using toluene as growth substrate in a laboratory-scale soil slurry. The aerobic simultaneous bioremoval of the cis-DCE/TCE/toluene mixture was studied under different conditions. Results showed that an increase in toluene concentration level from 300 to 900 mg/kg prolonged the lag phase for the bacterial growth, while the bioremoval extent for cis-DCE, TCE, and toluene declined as the initial toluene concentration increased. In addition, the cometabolic bioremoval of cis-DCE and TCE was inhibited by the presence of hydrogen peroxide as the additional oxygen source, while the bioremoval of toluene (900 mg/kg) was enhanced after 9 days of incubation. The subsequent addition of toluene did not improve the cometabolic bioremoval of cis-DCE and TCE. The obtained results would help to enhance the applicability of bioremediation technology to the mixed waste contaminated sites. PMID:25963576

  6. Determination of rate constants and branching ratios for TCE degradation by zero-valent iron using a chain decay multispecies model.

    PubMed

    Hwang, Hyoun-Tae; Jeen, Sung-Wook; Sudicky, Edward A; Illman, Walter A

    2015-01-01

    The applicability of a newly-developed chain-decay multispecies model (CMM) was validated by obtaining kinetic rate constants and branching ratios along the reaction pathways of trichloroethene (TCE) reduction by zero-valent iron (ZVI) from column experiments. Changes in rate constants and branching ratios for individual reactions for degradation products over time for two columns under different geochemical conditions were examined to provide ranges of those parameters expected over the long-term. As compared to the column receiving deionized water, the column receiving dissolved CaCO3 showed higher mean degradation rates for TCE and all of its degradation products. However, the column experienced faster reactivity loss toward TCE degradation due to precipitation of secondary carbonate minerals, as indicated by a higher value for the ratio of maximum to minimum TCE degradation rate observed over time. From the calculated branching ratios, it was found that TCE and cis-dichloroethene (cis-DCE) were dominantly dechlorinated to chloroacetylene and acetylene, respectively, through reductive elimination for both columns. The CMM model, validated by the column test data in this study, provides a convenient tool to determine simultaneously the critical design parameters for permeable reactive barriers and natural attenuation such as rate constants and branching ratios. PMID:25827100

  7. Determination of rate constants and branching ratios for TCE degradation by zero-valent iron using a chain decay multispecies model

    NASA Astrophysics Data System (ADS)

    Hwang, Hyoun-Tae; Jeen, Sung-Wook; Sudicky, Edward A.; Illman, Walter A.

    2015-06-01

    The applicability of a newly-developed chain-decay multispecies model (CMM) was validated by obtaining kinetic rate constants and branching ratios along the reaction pathways of trichloroethene (TCE) reduction by zero-valent iron (ZVI) from column experiments. Changes in rate constants and branching ratios for individual reactions for degradation products over time for two columns under different geochemical conditions were examined to provide ranges of those parameters expected over the long-term. As compared to the column receiving deionized water, the column receiving dissolved CaCO3 showed higher mean degradation rates for TCE and all of its degradation products. However, the column experienced faster reactivity loss toward TCE degradation due to precipitation of secondary carbonate minerals, as indicated by a higher value for the ratio of maximum to minimum TCE degradation rate observed over time. From the calculated branching ratios, it was found that TCE and cis-dichloroethene (cis-DCE) were dominantly dechlorinated to chloroacetylene and acetylene, respectively, through reductive elimination for both columns. The CMM model, validated by the column test data in this study, provides a convenient tool to determine simultaneously the critical design parameters for permeable reactive barriers and natural attenuation such as rate constants and branching ratios.

  8. Influence of humidity and of the electric and magnetic microwave radiation fields on the remediation of TCE-contaminated natural sandy soils.

    PubMed

    Horikoshi, Satoshi; Muratani, Masaru; Miyabe, Kouta; Ohmura, Keisuke; Hirowatari, Tomoaki; Serpone, Nick; Abe, Masahiko

    2011-01-01

    The influence of moisture content (15% w/w) on the remediation (vaporization) of trichloroethylene (TCE) present in natural sands, chosen as a TCE-polluted model system for soils, was investigated with regard to applied microwave power levels, the depth of the sand sample, and the dielectric factors. The heating process occurring in the sand samples arises through the microwave conduction loss heating and dielectric loss heating mechanisms. The characteristic relevance of the electric and magnetic microwave radiation fields to the heating mechanisms was also examined. Heating by the magnetic microwave radiation field was considerable when magnetite was added to the dry and wet sand samples as the microwave absorber. Optimal microwave conditions are reported for a single-mode microwave applicator. Near-quantitative elimination of the TCE contaminant was achieved for sandy soils within a very short time. PMID:21701102

  9. In situ redox manipulation of subsurface sediments from Fort Lewis, Washington: Iron reduction and TCE dechlorination mechanisms

    SciTech Connect

    JE Szecsody; JS Fruchter; DS Sklarew; JC Evans

    2000-03-21

    Pacific Northwest National Laboratory (PNNL) conducted a bench-scale study to determine how effective chemically treated Ft. Lewis sediments can degrade trichloroethylene (TCE). The objectives of this experimental study were to quantify: (1) sediment reduction and oxidation reactions, (2) TCE degradation reactions, and (3) other significant geochemical changes that occurred. Sediment reduction and oxidation were investigated to determine the mass of reducible iron in the Ft. Lewis sediments and the rate of this reduction and subsequent oxidation at different temperatures. The temperature dependence was needed to be able to predict field-scale reduction in the relatively cold ({approximately}11 C) Ft. Lewis aquifer. Results of these experiments were used in conjunction with other geochemical and hydraulic characterization to design the field-scale injection experiment and predict barrier longevity. For example, the sediment reduction rate controls the amount of time required for the dithionite solution to fully react with sediments. Sediment oxidation experiments were additionally conducted to determine the oxidation rate and provide a separate measure of the mass of reduced iron. Laboratory experiments that were used to meet these objectives included: (1) sediment reduction in batch (static) systems, (2) sediment reduction in 1-D columns, and (3) sediment oxidation in 1-D columns. Multiple reaction modeling was conducted to quantify the reactant masses and reaction rates.

  10. Occurrence of mental illness following prenatal and early childhood exposure to tetrachloroethylene (PCE)-contaminated drinking water: a retrospective cohort study

    PubMed Central

    2012-01-01

    Background While many studies of adults with solvent exposure have shown increased risks of anxiety and depressive disorders, there is little information on the impact of prenatal and early childhood exposure on the subsequent risk of mental illness. This retrospective cohort study examined whether early life exposure to tetrachloroethylene (PCE)-contaminated drinking water influenced the occurrence of depression, bipolar disorder, post-traumatic stress disorder, and schizophrenia among adults from Cape Cod, Massachusetts. Methods A total of 1,512 subjects born between 1969 and 1983 were studied, including 831 subjects with both prenatal and early childhood PCE exposure and 547 unexposed subjects. Participants completed questionnaires to gather information on mental illnesses, demographic and medical characteristics, other sources of solvent exposure, and residences from birth through 1990. PCE exposure originating from the vinyl-liner of water distribution pipes was assessed using water distribution system modeling software that incorporated a leaching and transport algorithm. Results No meaningful increases in risk ratios (RR) for depression were observed among subjects with prenatal and early childhood exposure (RR: 1.1, 95% CI: 0.9-1.4). However, subjects with prenatal and early childhood exposure had a 1.8-fold increased risk of bipolar disorder (N = 36 exposed cases, 95% CI: 0.9-1.4), a 1.5-fold increased risk post-traumatic stress disorder (N = 47 exposed cases, 95% CI: 0.9-2.5), and a 2.1-fold increased risk of schizophrenia (N = 3 exposed cases, 95% CI: 0.2-20.0). Further increases in the risk ratio were observed for bipolar disorder (N = 18 exposed cases, RR; 2.7, 95% CI: 1.3-5.6) and post-traumatic stress disorder (N = 18 exposed cases, RR: 1.7, 95% CI: 0.9-3.2) among subjects with the highest exposure levels. Conclusions The results of this study provide evidence against an impact of early life exposure to PCE on the risk of depression. In contrast, the results provide support for an impact of early life exposure on the risk of bipolar disorder and post-traumatic stress disorder. The number of schizophrenia cases was too small to draw reliable conclusions. These findings should be confirmed in investigations of other similarly exposed populations. PMID:22264316

  11. Heterogeneous carbonaceous matter in sedimentary rock lithocomponents causes significant trichloroethylene (TCE) sorption in a low organic carbon content aquifer/aquitard system.

    PubMed

    Choung, Sungwook; Zimmerman, Lisa R; Allen-King, Richelle M; Ligouis, Bertrand; Feenstra, Stanley

    2014-10-15

    This study evaluated the effects of heterogeneous thermally altered carbonaceous matter (CM) on trichloroethylene (TCE) sorption for a low fraction organic carbon content (foc) alluvial sedimentary aquifer and aquitard system (foc=0.046-0.105%). The equilibrium TCE sorption isotherms were highly nonlinear with Freundlich exponents of 0.46-0.58. Kerogen+black carbon was the dominant CM fraction extracted from the sediments and accounted for >60% and 99% of the total in the sands and silt, respectively. Organic petrological examination determined that the kerogen included abundant amorphous organic matter (bituminite), likely of marine origin. The dark calcareous siltstone exhibited the greatest TCE sorption among aquifer lithocomponents and accounted for most sorption in the aquifer. The results suggest that the source of the thermally altered CM, which causes nonlinear sorption, was derived from parent Paleozoic marine carbonate rocks that outcrop throughout much of New York State. A synthetic aquifer-aquitard unit system (10% aquitard) was used to illustrate the effect of the observed nonlinear sorption on mass storage potential at equilibrium. The calculation showed that >80% of TCE mass contained in the aquifer was sorbed on the aquifer sediment at aqueous concentration <1000 ?gL(-1). These results show that sorption is likely a significant contributor to the persistence of a TCE groundwater plume in the aquifer studied. It is implied that sorption may similarly contribute to TCE persistence in other glacial alluvial aquifers with similar geologic characteristics, i.e., comprised of sedimentary rock lithocomponents that contain thermally altered CM. PMID:25168960

  12. Superfund Record of Decision (EPA Region 7): Des Moines TCE Site, Operable Unit 3, Des Moines, IA. (Second remedial action), September 1992. Final report

    SciTech Connect

    Not Available

    1992-09-18

    The Des Moines TCE site is located southwest of downtown Des Moines, Polk County, Iowa. Land use in the area is predominantly industrial and commercial, and part of the site lies within the floodplain of the Raccoon River. Water from the Des Moines Water Works north infiltration gallery was found to be contaminated with trichloroethylene (TCE), dichloroethylene (DCE), and vinyl chloride at levels above accepted drinking water standards. The ROD addresses OU3, which encompasses potential sources of ground water contamination in an area north of the Raccoon River. The selected remedial action for OU3 includes no action with periodic groundwater monitoring.

  13. Time series geophysical monitoring of permanganate injections and in situ chemical oxidation of PCE, OU1 area, Savage Superfund Site, Milford, NH, USA.

    PubMed

    Harte, Philip T; Smith, Thor E; Williams, John H; Degnan, James R

    2012-05-01

    In situ chemical oxidation (ISCO) treatment with sodium permanganate, an electrically conductive oxidant, provides a strong electrical signal for tracking of injectate transport using time series geophysical surveys including direct current (DC) resistivity and electromagnetic (EM) methods. Effective remediation is dependent upon placing the oxidant in close contact with the contaminated aquifer. Therefore, monitoring tools that provide enhanced tracking capability of the injectate offer considerable benefit to guide subsequent ISCO injections. Time-series geophysical surveys were performed at a superfund site in New Hampshire, USA over a one-year period to identify temporal changes in the bulk electrical conductivity of a tetrachloroethylene (PCE; also called tetrachloroethene) contaminated, glacially deposited aquifer due to the injection of sodium permanganate. The ISCO treatment involved a series of pulse injections of sodium permanganate from multiple injection wells within a contained area of the aquifer. After the initial injection, the permanganate was allowed to disperse under ambient groundwater velocities. Time series geophysical surveys identified the downward sinking and pooling of the sodium permanganate atop of the underlying till or bedrock surface caused by density-driven flow, and the limited horizontal spread of the sodium permanganate in the shallow parts of the aquifer during this injection period. When coupled with conventional monitoring, the surveys allowed for an assessment of ISCO treatment effectiveness in targeting the PCE plume and helped target areas for subsequent treatment. PMID:22459605

  14. Application of a long-lasting colloidal substrate with pH and hydrogen sulfide control capabilities to remediate TCE-contaminated groundwater.

    PubMed

    Sheu, Y T; Chen, S C; Chien, C C; Chen, C C; Kao, C M

    2015-03-01

    A long-lasting emulsified colloidal substrate (LECS) was developed for continuous carbon and nanoscale zero-valent iron (nZVI) release to remediate trichloroethylene (TCE)-contaminated groundwater under reductive dechlorinating conditions. The developed LECS contained nZVI, vegetable oil, surfactants (Simple Green™ and lecithin), molasses, lactate, and minerals. An emulsification study was performed to evaluate the globule droplet size and stability of LECS. The results show that a stable oil-in-water emulsion with uniformly small droplets (0.7 ?m) was produced, which could continuously release the primary substrates. The emulsified solution could serve as the dispensing agent, and nZVI particles (with diameter 100-200 nm) were distributed in the emulsion evenly without aggregation. Microcosm results showed that the LECS caused a rapid increase in the total organic carbon concentration (up to 488 mg/L), and reductive dechlorination of TCE was significantly enhanced. Up to 99% of TCE (with initial concentration of 7.4 mg/L) was removed after 130 days of operation. Acidification was prevented by the production of hydroxide ion by the oxidation of nZVI. The formation of iron sulfide reduced the odor from produced hydrogen sulfide. Microbial analyses reveal that dechlorinating bacteria existed in soils, which might contribute to TCE dechlorination. PMID:25463237

  15. Uncertainties in pharmacokinetic modeling for perchloroethylene. I. Comparison of model structure, parameters, and predictions for low-dose metabolism rates for models derived by different authors.

    PubMed

    Hattis, D; White, P; Marmorstein, L; Koch, P

    1990-09-01

    In recent years physiologically based pharmacokinetic models have come to play an increasingly important role in risk assessment for carcinogens. The hope is that they can help open the black box between external exposure and carcinogenic effects to experimental observations, and improve both high-dose to low-dose and interspecies projections of risk. However, to date, there have been only relatively preliminary efforts to assess the uncertainties in current modeling results. In this paper we compare the physiologically based pharmacokinetic models (and model predictions of risk-related overall metabolism) that have been produced by seven different sets of authors for perchloroethylene (tetrachloroethylene). The most striking conclusion from the data is that most of the differences in risk-related model predictions are attributable to the choice of the data sets used for calibrating the metabolic parameters. Second, it is clear that the bottom-line differences among the model predictions are appreciable. Overall, the ratios of low-dose human to bioassay rodent metabolism spanned a 30-fold range for the six available human/rat comparisons, and the seven predicted ratios of low-dose human to bioassay mouse metabolism spanned a 13-fold range. (The greater range for the rat/human comparison is attributable to a structural assumption by one author group of competing linear and saturable pathways, and their conclusion that the dangerous saturable pathway constitutes a minor fraction of metabolism in rats.) It is clear that there are a number of opportunities for modelers to make different choices of model structure, interpretive assumptions, and calibrating data in the process of constructing pharmacokinetic models for use in estimating "delivered" or "biologically effective" dose for carcinogenesis risk assessments. We believe that in presenting the results of such modeling studies, it is important for researchers to explore the results of alternative, reasonably likely approaches for interpreting the available data--and either show that any conclusions they make are relatively insensitive to particular interpretive choices, or to acknowledge the differences in conclusions that would result from plausible alternative views of the world. PMID:2236748

  16. Six-phase soil heating for enhanced removal of contaminants: Volatile organic compounds in non-arid soils integrated demonstration, Savannah River Site

    SciTech Connect

    Gauglitz, P.A.; Bergsman, T.M.; Caley, S.M.

    1994-10-01

    In November 1993, Pacific Northwest Laboratory (PNL) and Savannah River Site (SRS) personnel conducted a demonstration of six-phase soil heating (SPSH) at the Savannah River Site (SRS) in Aiken, South Carolina. The demonstration was part of the Volatile Organic Compounds in Non-Arid Soils Integrated Demonstration being conducted near the M-Area operations at the SRS, along a corridor that once contained a process sewer leading to the M-Area seepage basin. In the early 1980s, this sewer line was discovered to be leaking process wastes into the subsurface and contributing to groundwater contamination in the vicinity of M-Area seepage basin. Although use of the sewer line has been discontinued, the slow release of chlorinated solvents such as trichloroethylene (TCE) and perchloroethylene (PCE) from the heterogeneous vadose zone soil continues to be a source of potential groundwater contamination. A significant portion of the VOCs at the demonstration site are retained in low-permeability clay zones. Previous studies have shown that the rate of conventional SVE remediation of the SRS clays is quite slow. The permeability of the clay is of order 10{sup {minus}12} cm{sup 2}, which makes this a particularly difficult interval to remediate. Thus, the challenge for SPSH is to effectively remediate this clay zone by accelerating the removal of TCE and PCE.

  17. Final Report on Testing of Off-Gas Treatment Technologies for Abatement of Atmospheric Emissions of Chlorinated Volatile Organic Compounds

    SciTech Connect

    Jarosch, T.R.; Haselow, J.S.; Rossabi, J.; Burdick, S.A.; Raymond, R.; Young, J.E.; Lombard, K.H.

    1995-01-23

    The purpose of this report is to summarize the results of the program for off-gas treatment of atmospheric emissions of chlorinated volatile organic compounds (CVOCs), in particular trichloroethylene (TCE) and perchloroethylene (PCE). This program was funded through the Department of Energy Office of Technology Development`s VOC`s in Non-Arid Soils Integrated Demonstration (VNID). The off-gas treatment program was initiated after testing of in-situ air stripping with horizontal wells was completed (Looney et al., 1991). That successful test expectedly produced atmospheric emissions of CVOCs that were unabated. It was decided after that test that an off-gas treatment is an integral portion of remediation of CVOC contamination in groundwater and soil but also because several technologies were being developed across the United States to mitigate CVOC emissions. A single platform for testing off-gas treatment technologies would facilitate cost effective evaluation of the emerging technologies. Another motivation for the program is that many CVOCs will be regulated under the Clean Air Act Amendments of 1990 and are already regulated by many state regulatory programs. Additionally, compounds such as TCE and PCE are pervasive subsurface environmental contaminants, and, as a result, a small improvement in terms of abatement efficiency or cost will significantly reduce CVOC discharges to the environment as well as costs to United States government and industry.

  18. Kinetics of chlorinated ethylene dehalogenation under methanogenic conditions

    SciTech Connect

    Skeen, R.S.; Gao, J.; Hooker, B.S.

    1995-12-20

    Kinetics were determined for methanogenic activity and chlorinated ethylene dehalogenation by a methanol-enriched, anaerobic sediment consortium. The culture reductively dechlorinated perchloroethylene (PCE) to trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), vinylchloride (VC), and ethylene and ethane. The absence of methanol or the addition of 2-bromoethanesulfonic acid in the presence of methanol suppressed both methanogenic activity and dechlorination. In contrast, acetate production continued in the presence of 2-bromoethanesulfonic acid. These results suggest that dechlorination was strongly linked to methane formation and not to acetate production. A kinetic model, developed to describe both methanogenesis and dechlorination, successfully predicted experimentally measured concentrations of biomass, methane, substrate, and chlorinated ethylenes. The average maximum specific dehalogenation rates for PCE, TCE, 1,1-DCE, and VC were 0.9 {+-} 0.6, 0.4 {+-} 0.1, 12 {+-} 0.1, and 2.5 {+-} 1.7 {micro}mol contaminant/g {center_dot} DW/day, respectively. This pattern for dechlorination rates is distinctly different than that reported for transition metal cofactors, where rates drop by approximately one order of magnitude as each successive chlorine is removed. The experimental results and kinetic analysis suggest that it will be impractical to targeting methanol consuming methanogenic organisms for in-situ groundwater restoration.

  19. Abiotic reductive dechlorination of cis-DCE by ferrous monosulfide mackinawite.

    PubMed

    Hyun, Sung Pil; Hayes, Kim F

    2015-11-01

    Cis-1,2,-dichloroethylene (cis-DCE) is a toxic, persistent contaminant occurring mainly as a daughter product of incomplete degradation of perchloroethylene (PCE) and trichloroethylene (TCE). This paper reports on abiotic reductive dechlorination of cis-DCE by mackinawite (FeS1-x ), a ferrous monosulfide, under variable geochemical conditions. To assess in situ abiotic cis-DCE dechlorination by mackinawite in the field, mackinawite suspensions prepared in a field groundwater sample collected from a cis-DCE contaminated field site were used for dechlorination experiments. The effects of geochemical variables on the dechlorination rates were monitored. A set of dechlorination experiments were also carried out in the presence of aquifer sediment from the site over a range of pH conditions to better simulate the actual field situations. The results showed that the suspensions of freshly prepared mackinawite reductively transformed cis-DCE to acetylene, whereas the conventionally prepared powder form of mackinawite had practically no reactivity with cis-DCE under the same experimental conditions. Significant cis-DCE degradation by mackinawite has not been reported prior to this study, although mackinawite has been shown to reductively transform PCE and TCE. This study suggests feasibility of using mackinawite for in situ remediation of cis-DCE-contaminated sites with high S levels such as estuaries under naturally achieved or stimulated sulfate-reducing conditions. PMID:26278897

  20. Investigation of the potential source area, contamination pathway, and probable release history of chlorinated-solvent-contaminated groundwater at the Capital City Plume Site, Montgomery, Alabama, 2008-2010

    USGS Publications Warehouse

    Landmeyer, James E.; Miller, Scott; Campbell, Bruce G.; Vroblesky, Don A.; Gill, Amy C.; Clark, Athena P.

    2011-01-01

    Detection of the organic solvent perchloroethylene (PCE) in a shallow public-supply well in 1991 and exposure of workers in 1993 to solvent vapors during excavation activities to depths near the water table provided evidence that the shallow aquifer beneath the capital city of Montgomery, Alabama, was contaminated. Investigations conducted from 1993 to 1999 by State and Federal agencies confirmed the detection of PCE in the shallow aquifer, as well as the detection of the organic solvent trichloroethylene (TCE) and various inorganic compounds, but the source of the groundwater contamination was not determined. In May 2000 the U.S. Environmental Protection Agency proposed that the site, called the Capital City Plume (CCP) Site, be a candidate for the National Priorities List. Between 2000 and 2007, numerous site-investigation activities also did not determine the source of the groundwater contamination. In 2008, additional assessments were conducted at the CCP Site to investigate the potential source area, contamination pathway, and the probable release history of the chlorinated-solvent-contaminated groundwater. The assessments included the collection of (1) pore water in 2008 from the hyporheic zone of a creek using passive-diffusion bag samplers; (2) tissue samples in 2008 and 2009 from trees growing in areas of downtown Montgomery characterized by groundwater contamination and from trees growing in riparian zones along the Alabama River and Cypress Creek; and (3) groundwater samples in 2009 and 2010. The data collected were used to investigate the potential source area of contaminants detected in groundwater, the pathway of groundwater contamination, and constraints on the probable contaminant-release history. The data collected between 2008 and 2010 indicate that the PCE and TCE contamination of the shallow aquifer beneath the CCP Site most likely resulted from the past use and disposal of industrial wastewater from printing operations containing chlorinated solvents into the sanitary sewer and (or) stormwater systems of Montgomery. Moreover, chlorinated-solvent use and disposal occurred at least between the 1940s and 1970s at several locations occupied by printing operations. The data also indicate that PCE and TCE contamination continues to occur in the shallow subsurface near potential release areas and that PCE and TCE have been transported to the intermediate part of the shallow aquifer.

  1. The in-situ decontamination of sand and gravel aquifers by chemically enhanced solubilization of multiple-component DNAPLS with surfactant solutions. Topical report

    SciTech Connect

    1995-01-01

    Laboratory, numerical simulation, and field studies have been conducted to assess the potential use of micellar-surfactant solutions to solubilize chlorinated solvents contaminating sand and gravel aquifers. Laboratory studies were conducted at the State University of New York at Buffalo (SUNY) while numerical simulation and field work were undertaken by INTERA Inc. in collaboration with Martin Marietta Energy Systems Inc. at the Paducah Gaseous Diffusion Plant (PGDP) in Kentucky. Ninety-nine surfactants were screened for their ability to solubilize trichloroethene (TCE), perchloroethylene (PCE), and carbon tetrachloride (CTET). Ten of these were capable of solubilizing TCE to concentrations greater than 15,000 mg/L, compared to its aqueous solubility of 1,100 mg/L. Four surfactants were identified as good solubilizers of all three chlorinated solvents. Of these, a secondary alcohol ethoxylate was the first choice for in situ testing because of its excellent solubilizing ability and its low propensity to sorb. However, this surfactant did not meet the Commonwealth of Kentucky`s acceptance criteria. Consequently, it was decided to use a surfactant approved for use by the Food and Drug Administration as a food-grade additive. As a 1% micellar-surfactant solution, this sorbitan monooleate has a solubilization capacity of 16,000 mg TCE/L, but has a higher propensity to sorb to clays than has the alcohol ethoxylate.

  2. Use of poly-beta-hydroxy-butyrate as a slow-release electron donor for the microbial reductive dechlorination of TCE.

    PubMed

    Aulenta, F; Fuoco, M; Canosa, A; Petrangeli Papini, M; Majone, M

    2008-01-01

    In situ anaerobic reductive dechlorination, using slow-release electron donors, is emerging as an effective and sustainable (low-cost and low-maintenance) technology to remediate aquifers contaminated by chloroethenes. In the present study, we investigated the use of poly-beta-hydroxy-butyrate (PHB), a fully biodegradable polymer, as a slow-release source of hydrogen and acetate for the reductive dechlorination of trichloroethene (TCE). Results of this study indicated that TCE dechlorination in PHB-amended microcosms was 2.3-times higher than in non-amended controls. This higher activity was explained by a higher H(2) level in PHB-amended microcosms. As usual, acetate was the major sink (approximately 90%) of reducing equivalents available from PHB degradation, whereas no acetotrophic dechlorination was observed. PMID:18413954

  3. Development of an integrated, in-situ remediation technology. Topical report for task No. 9. Part I. TCE degradation using nonbiological methods, September 26, 1994--May 25, 1996

    SciTech Connect

    Shapiro, A.P.; Sivavec, T.M.; Baghel, S.S.

    1997-04-01

    Contamination in low-permeability soils poses a significant technical challenge for in situ remediation efforts. Poor accessibility to the contaminants and difficulty in delivery of treatment reagents have rendered existing in situ treatments such as bioremediation, vapor extraction, pump and treat rather ineffective when applied to low-permeability soils present at many contaminated sites. The technology is an integrated in situ treatment in which established geotechnical methods are used to install degradation zones directly in the contaminated soil and electro-osmosis is used to move the contaminants back and forth through those zones until the treatment is completed. The present Draft Topical Report for Task No. 9 summarizes laboratory investigations into TCE degradation using nonbiological methods. These studies were conducted by the General Electric Company. The report concentrates on zero valent iron as the reducing agent and presents data on TCE and daughter product degradation rates in batch experiments, column studies, and electroosmotic cells. It is shown that zero valent iron effectively degrades TCE in electroosmotic experiments. Daughter product degradation and gas generation are shown to be important factors in designing field scale treatment zones for the Lasagna{trademark} process.

  4. Efficient Degradation of TCE in Groundwater Using Pd and Electro-generated H2 and O2: A Shift in Pathway from Hydrodechlorination to Oxidation in the Presence of Ferrous Ions

    PubMed Central

    Yuan, Songhu; Mao, Xuhui; Alshawabkeh, Akram N.

    2012-01-01

    Degradation of trichloroethylene (TCE) in simulated groundwater by Pd and electro-generated H2 and O2 is investigated in the absence and presence of Fe(II). In the absence of Fe(II), hydrodechlorination dominates TCE degradation, with accumulation of H2O2 up to 17 mg/L. Under weak acidity, low concentrations of oxidizing •OH radical are detected due to decomposition of H2O2, slightly contributing to TCE degradation via oxidation. In the presence of Fe(II), the degradation efficiency of TCE at 396 ?M improves to 94.9% within 80 min. The product distribution proves that the degradation pathway shifts from 79% hydrodechlorination in the absence of Fe(II) to 84% •OH oxidation in the presence of Fe(II). TCE degradation follows zeroth-order kinetics with rate constants increasing from 2.0 to 4.6 ?M/min with increasing initial Fe(II) concentration from 0 to 27.3 mg/L at pH 4. A good correlation between TCE degradation rate constants and •OH generation rate constants confirms that •OH is the predominant reactive species for TCE oxidation. Presence of 10 mM Na2SO4, NaCl, NaNO3, NaHCO3, K2SO4, CaSO4 and MgSO4 does not significantly influence degradation, but sulfite and sulfide greatly enhance and slightly suppresses degradation, respectively. A novel Pd-based electrochemical process is proposed for groundwater remediation. PMID:22315993

  5. Plume persistence caused by back diffusion from thin clay layers in a sand aquifer following TCE source-zone hydraulic isolation.

    PubMed

    Parker, Beth L; Chapman, Steven W; Guilbeault, Martin A

    2008-11-14

    This paper concludes that back diffusion from one or a few thin clayey beds in a sand aquifer can cause contaminant persistence above MCLs in a sand aquifer long after the source zone initially causing the plume is isolated or removed. This conclusion is based on an intensive case study of a TCE contaminated site in Florida, with the processes evaluated using numerical modeling. At this site, the TCE DNAPL zone formed decades ago, and was hydraulically isolated by means of an innovative system performing groundwater extraction, treatment and re-injection. Treated water is re-injected in a row of injection wells situated a short distance downgradient of the extraction wells, creating a clean-water displacement front to efficiently flush the downgradient plume. This scheme avoids the creation of stagnation zones typical of most groundwater pump-and-treat systems, thereby minimizing the time for aquifer flushing and therefore downgradient cleanup. The system began operation in August 2002 and although the performance monitoring shows substantial declines in concentrations, detectable levels of TCE and degradation products persist downgradient of the re-injection wells, long after the TCE should have disappeared based on calculations assuming a nearly homogenous sand aquifer. Three hypotheses were assessed for this plume persistence: 1) incomplete source-zone capture, 2) DNAPL occurrence downgradient of the re-injection wells, and 3) back diffusion from one or more thin clay beds in the aquifer. After careful consideration, the first two hypotheses were eliminated, leaving back diffusion as the only plausible hypothesis, supported by detailed measurements of VOC concentrations within and near the clay beds and also by numerical model simulations that closely represent the field site hydrogeologic conditions. The model was also used to simulate a more generalized, hypothetical situation where more thin clayey beds occur in a sand aquifer with an underlying aquitard. While there is no doubt that DNAPL source mass reduction can eventually improve downgradient groundwater quality, the magnitude and time scale over which the improvement occurs is the major uncertainty given current characterization approaches. This study shows that even one thin clay bed, less than 0.2 m thick, can cause plume persistence due to back diffusion for several years or even decades after the flux from the source is completely isolated. Thin clay beds, which have a large storage capacity for dissolved and sorbed contaminant mass, are common in many types of sandy aquifers. However, without careful inspection of continuous cores and sampling, such thin clay beds, and their potential for causing long-term back-diffusion effects, can easily go unnoticed during site characterization. PMID:18775583

  6. 1992 toxic hazards research unit annual report. Annual report, 1 October 1991-30 September 1992

    SciTech Connect

    Wall, H.G.; Dodd, D.E.; Vinegar, A.; Schneider, M.G.

    1993-04-01

    This report presents a review of the activities of the Toxic Hazards Research Unit (THRU) for the period 1 October 1991 through 30 September 1992. The THRU conducts descriptive, mechanistic, and predictive toxicology research and toxicological risk assessments to provide data to predict health hazards and to assess health risks associated with human exposure to chemicals and materials associated with military systems and operational environments. The report includes summaries of ongoing or completed research activities for the individual toxicology research requirements of the U.S. Air Force, Army, and Navy; highlights of the research support elements and conference activities of the THRU; and appendices that describe the THRU organization and its publications and presentations. 1,3,3-Trinitroazetidine (TNAZ), 1,3,5-Trinitrobenzene (TNB), Carboxylic acid metabolite, Chlorofluorocarbon, Chloroform, Delayed neurotoxicity, Halon replacement, Hydraulic fluid, Hydrazine, Inhalation, Jet engine oil, Lactational transfer, Methylene chloride, MIL-H-19457C, Neurotoxic Esterase (NTE), OTTO Fuel II, Perchloroethylene (PCE), Physiologically Based Pharmacokinetic (PBPK) modeling, Polychlorotrifluoroethylene (pCTFE), Quantitative Structure-Activity Relationships (QSAR), Reproductive, Risk assessment, Smoke, Tetrachloroethylene (PCE), Toxic dust, Vinyl Chloride (VC) and Trichloroethylene (TCE) mixture.

  7. Airlift recirculation well test results -- Southern sector

    SciTech Connect

    White, R.M.; Hiergesell, R.A.

    1997-08-01

    Chlorinated solvents used in the A and M-Areas at the Savannah River Site (SRS) from 1952--1982 have contaminated the groundwater under the site. A plume of groundwater contaminated with trichloroethylene (TCE) and perchloroethylene (PCE) in the Lost Lake aquifer is moving generally southward with the natural flow of groundwater. To comply with the requirements of the current SCDHEC Part B Permit, a series of wells is being installed to contain and treat the plume. Airlift Recirculation Wells (ARW) are a new and innovative technology with potential for more cost effective implementation than conventional pump and treat systems. Two Airlift Recirculation Wells have been installed and tested to quantify performance parameters needed to locate a line of these wells along the leading edge of the contaminant plume. The wells proved to be very sensitive to proper development, but after this requirement was met, performance was very good. The Zone of Capture has been estimated to be within a radius of 130--160 ft. around the wells. Thus a line of wells spaced at 250 ft. intervals could intercept the contaminant plume. At SSR-012, TCE was stripped from the groundwater at approximately 1.2 lb./day. The longer term effect of the recirculation wells upon the plume and the degree of recirculation within the aquifer itself will require additional data over a longer time period for an accurate review. Data collection is ongoing.

  8. Role of layer packing for the electronic properties of the organic superconductor (BEDT-TTF ) 2Ag (CF3)4(TCE )

    NASA Astrophysics Data System (ADS)

    Altmeyer, Michaela; Valentí, Roser; Jeschke, Harald O.

    2015-06-01

    The charge-transfer compound (BEDT-TTF ) 2Ag (CF3)4(TCE ) crystallizes in three polymorphs with different alternating layers: While a phase with a ? packing motif has a low superconducting transition temperature of Tc=2.6 K , two phases with higher Tc of 9.5 and 11 K are multilayered structures consisting of ?' and ? layers. We investigate these three systems within density functional theory and find that the ?' layer shows different degrees of charge order for the two ? -?' systems and directly influences the electronic behavior of the conducting ? layer. We discuss the origin of the distinct behavior of the three polymorphs and propose a minimal tight-binding Hamiltonian for the description of these systems based on projective molecular Wannier functions.

  9. Competitive Sorption and Desorption of Chlorinated Organic Solvents (DNAPLs) in Engineered Natural Organic Matter

    SciTech Connect

    Tang, Jixin; Weber, Walter J., Jr.

    2004-03-31

    The effects of artificially accelerated geochemical condensation and maturation of natural organic matter on the sorption and desorption of trichloroethylene (TCE) and tetrachloroethylene (PCE) were studied. The sorption and desorption of TCE in the presence and absence of the competing PCE and 1,2-dichlorobenzene (DCB) were also examined. A sphagnum peat comprising geologically young organic matter was artificially ''aged'' using superheated water, thus increasing the aromaticity and the degree of condensation of its associated organic matter. The sorption of all solutes tested were increased remarkably and their respective desorptions reduced, by the aged peat. The sorption capacities and isotherm nonlinearities of the peat for both TCE and PCE were found to increase as treatment temperature increased. In the competitive sorption studies, both PCE and DCB were found to depress TCE sorption, with PCE having greater effects than DCB, presumably because the molecular structure o f the former is more similar to that of TCE.

  10. Development of an integrated in-situ remediation technology. Topical report for task No. 11 entitled: Evaluation of TCE contamination before and after the field experiment, September 26, 1994--May 25, 1996

    SciTech Connect

    Hughes, B.M.; Athmer, C.J.; Sheridan, P.W.

    1997-04-01

    Contamination in low permeability soils poses a significant technical challenge to in-situ remediation efforts. Poor accessibility to the contaminants and difficulty in delivery of treatment reagents have rendered existing in-situ treatments such as bioremediation, vapor extraction, pump and treat rather ineffective when applied to low permeability soils present at many contaminated sites. The technology is an integrated in-situ treatment in which established geotechnical methods are used to install degradation zones directly in the contaminated soil and electro-osmosis is utilized to move the contaminants back and forth through those zones until the treatment is completed. The present Topical Report for Task No. 11 summarizes the results of TCE analysis in soil and carbon before and after conducting the field experiment. In addition, a discussion of the TCE material balance demonstrates that the Lasagna{trademark} process is effective in moving TCE from the contaminated soil into carbon treatment zones in the field experiment at DOE`s Gaseous Diffusion Plant in Paducah, Kentucky.

  11. HEALTH ASSESSMENT DOCUMENT FOR TETRACHLOROETHYLENE (PERCHLOROETHYLENE)

    EPA Science Inventory

    Tetrachloroethylene (PERC) is believed to exert its adverse effects upon humans via metabolism by the liver. Concern that PERC is likely to be a human carcinogen is based upon the evidence of the National Cancer Institute bioassay, in which PERC induced a statistically significan...

  12. Desorption Behavior of Trichloroethene and Tetrachloroethene in U.S. Department of Energy Savannah River Site Unconfined Aquifer Sediments

    SciTech Connect

    Riley, Robert G.; Szecsody, Jim E.; Mitroshkov, Alexandre V.; Brown, Christopher F.

    2006-06-21

    The DOE Savannah River Site (SRS) is evaluating the potential applicability of the monitored natural attenuation (MNA) process as a contributor to the understanding of the restoration of its unconfined groundwater aquifer known to be contaminated with the chlorinated hydrocarbon compounds trichloroethylene (TCE) and tetrachloroethylene (PCE). This report discusses the results from aqueous desorption experiments on SRS aquifer sediments from two different locations at the SRS (A/M Area; P-Area) with the objective of providing technically defensible TCE/PCE distribution coefficient (Kd) data and data on TCE/PCE reversible and irreversible sorption behavior needed for further MNA evaluation.

  13. The state of permanganate with relation to in situ chemical oxidation

    SciTech Connect

    Veronda, Brenda; Dingens, Matthew

    2007-07-01

    In Situ Chemical Oxidation (ISCO) with permanganate had its beginnings over 10 years ago. Since that time, many sites have been successfully treated for organic compounds including chlorinated ethenes (perchloroethylene, trichloroethylene, etc.) phenols, explosives such as RDX, and many other organics. The successful application of ISCO with permanganate requires the integration of many site-specific factors into the remedial design. ISCO with permanganate is an effective technology, not only for its oxidative properties and persistence, but also for its application flexibility to remediate soil and groundwater. The merits of any type of treatment technology can be assessed in terms of effectiveness, ease of use, reaction rate, and cost. The use of permanganate for in situ chemical oxidation results in the complete mineralization of TCE and PCE and can result in treatment levels below detection limits. Permanganate is a single component oxidizer, which is easily handled, mixed and distributed to the subsurface. Permanganate is also inexpensive to design and implement as compared to other technologies. This presentation will provide a general overview of the application and safety aspects of ISCO with permanganate. This paper will discuss the advantages and limitations of this technology, typical cost ranges, site evaluation and application technologies. (authors)

  14. Halocarbons in the environment: estimates of thermodynamic properties for aqueous chloroethylene species and their stabilities in natural settings

    NASA Astrophysics Data System (ADS)

    Haas, Johnson R.; Shock, Everett L.

    1999-10-01

    Standard partial molal thermodynamic parameters for the aqueous chlorinated-ethylene species, perchloroethylene (PCE), trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), cis-1,2-dichloroethylene (cis-1,2-DCE), trans-1,2-dichloroethylene (trans-1,2,-DCE), and vinyl chloride (VC) have been estimated by using experimental gas-solubility data and correlation algorithms. The provided thermodynamic values may be used to calculate properties of reactions involving the aqueous chloroethylene species at a wide range of temperatures and pressures. Estimated values for the chloroethylenes were used, along with published values for minerals, gases, aqueous ions, and aqueous neutral organic species, to calculate the stability of chloroethylene species in equilibrium with the minerals magnetite, hematite, pyrite, and pyrrhotite in the subsurface. Estimated values for the aqueous chloroethylenes were also used to calculate reduction potentials for microbially-mediated reductive dechlorination half-reactions at elevated temperatures. Calculations indicate that all aqueous chloroethylene species are energetically favored to decompose to ethylene(aq) under a wide range of conditions in the subsurface, by both abiotic and biotic pathways. Anaerobic microbially mediated degradation is especially favored under conditions at least sufficiently reducing to promote sulfate-reduction, but not under conditions sufficient for microbial denitrification, pyrolusite reduction, or ferric-iron reduction.

  15. Technology status report: Off-gas treatment technologies for chlorinated volatile organic compound air emissions

    SciTech Connect

    Rossabi, J.; Haselow, J.S.

    1992-04-15

    The purpose of this document is to review technologies for treatment of air streams that contain chlorinated volatile organic compounds (CVOCS) and to describe a Department of Energy Office of Technology Development program that is planned to demonstrate innovative technologies for the abatement of CVOC emissions. This report describes the first phase of testing of off-gas treatment technologies. At least one more phase of testing is planned. Guidance for the preparation of this document was provided by a predecisional draft outline issued by the Department of Energy`s Office of Technology Development. The report is intended to evaluate the technical and regulatory aspects, public acceptance, and estimated costs of technologies selected for development and testing. These technologies are compared to currently practiced or baseline methods for treatment of CVOC-laden airstreams. A brief overview is provided rather than detailed cost and data comparisons because many of these technologies have not yet been field tested. A description of other promising technologies for the treatment of CVOC emissions is also included. Trichloroethylene (TCE) and perchloroethylene (PCE) were used for industrial cleaning and solvent applications for several decades. These chemicals can be classified as CVOCS. As a result of past standard disposal practices, these types of compounds are persistent groundwater and soil contaminants throughout the United States and the Department of Energy Complex.

  16. Technology status report: Off-gas treatment technologies for chlorinated volatile organic compound air emissions

    SciTech Connect

    Rossabi, J.; Haselow, J.S.

    1992-04-15

    The purpose of this document is to review technologies for treatment of air streams that contain chlorinated volatile organic compounds (CVOCS) and to describe a Department of Energy Office of Technology Development program that is planned to demonstrate innovative technologies for the abatement of CVOC emissions. This report describes the first phase of testing of off-gas treatment technologies. At least one more phase of testing is planned. Guidance for the preparation of this document was provided by a predecisional draft outline issued by the Department of Energy's Office of Technology Development. The report is intended to evaluate the technical and regulatory aspects, public acceptance, and estimated costs of technologies selected for development and testing. These technologies are compared to currently practiced or baseline methods for treatment of CVOC-laden airstreams. A brief overview is provided rather than detailed cost and data comparisons because many of these technologies have not yet been field tested. A description of other promising technologies for the treatment of CVOC emissions is also included. Trichloroethylene (TCE) and perchloroethylene (PCE) were used for industrial cleaning and solvent applications for several decades. These chemicals can be classified as CVOCS. As a result of past standard disposal practices, these types of compounds are persistent groundwater and soil contaminants throughout the United States and the Department of Energy Complex.

  17. Innovative Technologies And Vadose Zone Treatment Of Chlorinated Volatile Organic Compounds - Case Study

    SciTech Connect

    NOONKESTER, JAY V.; NICHOLS, RALPH L.; DIXON, KENETH L.

    2005-08-02

    Over the last 10 years a mix of innovative and conventional characterization techniques has been used to assess the contamination of vadose zone sediments beneath the pilot-scale test facility known as TNX at the Savannah River Site (SRS) in South Carolina. Shallow soils and groundwater beneath the TNX facility are contaminated with chlorinated volatile organic compounds (CVOCs), trichloroethylene (TCE), carbon tetrachloride (CCl{sub 4}), perchloroethylene (PCE), and chloroform (CHCl{sub 3}). An interim pump and treat remediation system was placed in operation in 1996 to provide hydraulic containment of groundwater containing greater than 500 ug/L dissolved TCE. In 1994, a vadose zone study was initiated to determine the degree and extent of CVOC contamination above the contaminated groundwater. Headspace sampling and analysis, acoustic infrared spectroscopy, cone penetrometry, and vadose zone pumping tests were used to determine contaminant concentrations and physical properties related to soil vapor extraction. In 2001, soil vapor extraction (SVE), a presumptive remedy for CVOCs in soils similar to those present beneath TNX, was selected to treat the CVOC contamination. Cone Penetrometer Testing (CPT) with soil vapor sampling provided a detailed understanding of the subsurface geology and CVOC distribution which was essential for proper well design and placement. Twelve SVE wells were installed using direct push technology (DPT) and were tested to determine specific capacity and CVOC concentrations. This information was then used to develop a strategy for operating the SVE system. Based on the results of the baseline testing and previous studies, sets of 2 to 3 extraction wells will be treated using SVE at one month intervals. This will allow continuous operation of the SVE system and give individual wells up to 3 months for rebound between treatments. This method of operation is intended to maximize contaminant recovery from individual wells and reduce the overall capital investment and operating cost of the SVE system.

  18. Green remediation: enhanced reductive dechlorination using recycled rinse water as bioremediation substrate

    SciTech Connect

    Dawson, Gaynor; McKeon, Tom

    2007-07-01

    Enhanced reductive dechlorination (ERD) has rapidly become a remedy of choice for use on chlorinated solvent contamination when site conditions allow. With this approach, solutions of an organic substrate are injected into the affected aquifer to stimulate biological growth and the resultant production of reducing conditions in the target zone. Under the reducing conditions, hydrogen is produced and ultimately replaces chlorine atoms on the contaminant molecule causing sequential dechlorination. Under suitable conditions the process continues until the parent hydrocarbon precursor is produced, such as the complete dechlorination of trichloroethylene (TCE) to ethene. The process is optimized by use of a substrate that maximizes hydrogen production per unit cost. When natural biota are not present to promote the desired degradation, inoculates can be added with the substrate. The in-situ method both reduces cost and accelerates cleanup. Successful applications have been extended from the most common chlorinated compounds perchloroethylene (PCE) and TCE and related products of degradation, to perchlorate, and even explosives such as RDX and trinitrotoluene on which nitrates are attacked in lieu of chloride. In recent work, the process has been further improved through use of beverage industry wastewaters that are available at little or no cost. With material cost removed from the equation, applications can maximize the substrate loading without significantly increasing total cost. The extra substrate loading both accelerates reaction rates and extends the period of time over which reducing conditions are maintained. In some cases, the presence of other organic matter in addition to simple sugars provides for longer performance times of individual injections, thereby working in a fashion similar to emulsified vegetable oil. The paper discusses results of applications at three different sites contaminated with chlorinated ethylenes. The applications have included wastewaters of both natural fruit juices and corn syrup solutions from carbonated beverages. Cost implications include both the reduced cost of substrate and the cost avoidance of needing to pay for treatment of the wastewater. (authors)

  19. RHIZOSPHERE MICROBIOLOGY OF CHLORINATED ETHENE CONTAMINATED SOILS: EFFECTS ON PHOSPHOLIPID FATTY ACID CONTENT

    SciTech Connect

    Brigmon, R. L.; Stanhopc, A.; Franck, M. M.; McKinsey, P. C.; Berry, C. J.

    2005-05-26

    Microbial degradation of chlorinated ethenes (CE) in rhizosphere soils was investigated at seepline areas impacted by CE plumes. Successful bioremediation of CE in rhizosphere soils is dependent on microbial activity, soil types, plant species, and groundwater CE concentrations. Seepline soils were exposed to trichloroethylene (TCE) and perchloroethylene (PCE) in the 10-50 ppb range. Greenhouse soils were exposed to 2-10 ppm TCE. Plants at the seepline were poplar and pine while the greenhouse contained sweet gum, willow, pine, and poplar. Phospholipid fatty acid (PLFA) analyses were performed to assess the microbial activity in rhizosphere soils. Biomass content was lowest in the nonvegetated control soil and highest in the Sweet Gum soil. Bacterial rhizhosphere densities, as measured by PLFA, were similar in different vegetated soils while fungi biomass was highly variable. The PLFA soil profiles showed diverse microbial communities primarily composed of Gram-negative bacteria. Adaptation of the microbial community to CE was determined by the ratio of {omega}7t/{omega}7c fatty acids. Ratios (16:1{omega}7v16:1{omega}7c and 18:l{omega}7t/18:1{omega}7c) greater than 0.1 were demonstrated in soils exposed to higher CE concentrations (10-50 ppm), indicating an adaptation to CE resulting in decreased membrane permeability. Ratios of cyclopropyl fatty acids showed that the vegetated control soil sample contained the fastest microbial turnover rate and least amount of environmental stress. PLFA results provide evidence that sulfate reducing bacteria (SRB) are active in these soils. Microcosm studies with these soils showed CE dechlorinating activity was occurring. This study demonstrates microbial adaptation to environmental contamination and supports the application of natural soil rhizosphere activity as a remedial strategy.

  20. DETERMINATION OF CHLOROETHENES IN ENVIRONMENTAL BIOLOGICAL SAMPLES USING GAS CHROMATOGRAPHY COUPLED WITH SOLID PHASE MICRO EXTRACTION

    EPA Science Inventory

    An analytical method has been developed to determine the chloroethene series, tetrachloroethene (PCE), trichloroethene (TCE),cisdichloroethene (cis-DCE) andtransdichloroethene (trans-DCE) in environmental biotreatment studies using gas chromatography coupled with a solid phase mi...

  1. Applications of Monitored Natural Attenuation in the USA (Presentation)

    EPA Science Inventory

    Monitored Natural Attenuation (MNA) is widely applied in the USA to control the risk associated with ground water contamination from chlorinated solvents such a tetrachloroethylene (PCE) and trichloroethylene (TCE). MNA relies on the natural processes of degradation, sorption an...

  2. Applications of Monitored Natural Attenuation in the USA (Abstract)

    EPA Science Inventory

    Monitored Natural Attenuation (MNA) is widely applied in the USA to control the risk associated with ground water contamination from chlorinated solvents such a tetrachloroethylene (PCE) and trichloroethylene (TCE). MNA relies on the natural processes of degradation, sorption an...

  3. DEMONSTRATION BULLETIN: AQUADETOX®/ SVE SYSTEM and AWD Technologies, Inc.

    EPA Science Inventory

    The AWD technology simultaneously treats groundwater and soil-gas contaminated with volatile or ganic compounds (VOC), such as trichloroethylene (TCE) and tetrachloroethylene (PCE). This technology integrates two processes: (1) AquaDetox®, a moderate vacuum (pressure about 50 ...

  4. Contributions of Fe Minerals to Abiotic Dechlorination

    EPA Science Inventory

    Most applications of enhanced in situ bioremediation are based on biological reductive dechlorination. Anaerobic metabolism can also produce reactive minerals that allow for in situ biogeochemical transformation of chlorinated organic contaminants such as PCE, TCE, and cis-DCE. ...

  5. MICROEMULSION OF MIXED CHLORINATED SOLVENTS USING FOOD GRADE (EDIBLE) SURFACTANTS

    EPA Science Inventory

    Ground water contamination frequently consists of mixed chlorinated solvents [e.g., tetrachloroethylene (PCE), trichloroethylene (TCE), and trans-1,2- dichloroethylene (DCE)]. In this research, mixtures of the food grade (edible) surfactants bis(2-ethylhexyl) sodium sulfosuccinat...

  6. BIODEGRADATION OF CHLORINATED SOLVENTS: REACTIONS NEAR DNAPL AND ENZYME FUNCTION

    EPA Science Inventory

    Chlorinated solvents are among the most common organic chemical groundwater contaminants at DOE sites, as well as at DOD and industrial facilities. Included are the solvents trichloroethene (TCE), tetrachloroethene (PCE), and carbon tetrachloride (CT). Commonly these contaminan...

  7. IN-PLACE REGENERATION OF SVE LOADED GAC USING FENTON'S REAGENTS

    EPA Science Inventory

    Ten out of the 25 most frequently detected groundwater contaminants at hazardous waste sites are chlorinated volatile organic compounds (VOCs) 1 . Trichloroethylene (TCE) and tetrachloroethylene (PCE) are among the top three 1 . Granular activated carbon (GAC) adsorption is w...

  8. IN-PLACE REGENERATION OF SVE LOADED GAC USING FENTON'S REAGENTS

    EPA Science Inventory

    Ten out of the 25 most frequently detected groundwater contaminants at hazardous waste sites are chlorinated volatile organic compounds (VOCs) 1. Trichloroethylene (TCE) and tetrachloroethylene (PCE) are among the top three 1. Granular activated carbon (GAC) adsorption is widel...

  9. Promising Emerging Mechanisms

    EPA Science Inventory

    Most applications of enhanced in situ bioremediation are based on biological reductive dechlorination. Anaerobic metabolism can also produce reactive minerals that allow for in situ biogeochemical transformation of chlorinated organic contaminants such as PCE, TCE, and cis-DCE. ...

  10. SURFACTANT-ENHANCED SOLUBILIZATION OF TETRACHLOROETHYLENE AND DEGRADATION PRODUCTS IN PUMP AND TREAT REMEDIATION

    EPA Science Inventory

    Experiments were conducted to investigate the enhanced solubilization of tetrachloroethylene (PCE), trichloroethylene (TCE), and 1,2-dichloroethylene (DCE) in nonionic surfactant solutions of Triton X-100, Brij-30, Igepal CA-720, and Tergitol NP-10 (alkylpolyoxyethylenes). urfact...

  11. EFFECTS OF FOUR TRIHALOMETHANES ON DNA STRAND BREAKS, RENAL HYALINE DROPLET FORMATION AND SERUM TESTOSTERONE IN MALE F-344 RATS

    EPA Science Inventory

    All four possible trihalomethanes (THMs) containing bromine and chlorine, as well as perchloroethylene (PCE), were evaluated for their ability to produce DNA strand breaks, a2u-globulin rich renal deposits, and testosterone changes in male F-344 rats. Rats received daily equimola...

  12. CONTROLLED RELEASE, BLIND TEST OF DNAPL REMEDIATION BY ETHANOL FLUSHING

    EPA Science Inventory

    A dense nonaqueous phase liquid (DNAPL) source zone was established within a sheet-pile
    isolated cell through a controlled release of perchloroethylene (PCE) to evaluate DNAPL
    remediation by in-situ cosolvent flushing. Ethanol was used as the cosolvent, and the main remedia...

  13. Degradation of Environmental Contaminants with Water-Soluble Cobalt Catalysts: An Integrative Inorganic Chemistry Investigation

    ERIC Educational Resources Information Center

    Evans, Alexandra L.; Messersmith, Reid E.; Green, David B.; Fritsch, Joseph M.

    2011-01-01

    We present an integrative laboratory investigation incorporating skills from inorganic chemistry, analytical instrumentation, and physical chemistry applied to a laboratory-scale model of the environmental problem of chlorinated ethylenes in groundwater. Perchloroethylene (C[subscript 2]Cl[subscript 4], PCE) a common dry cleaning solvent,…

  14. Monitoring the decontamination of a site polluted by DNAPLs

    NASA Astrophysics Data System (ADS)

    Audí-Miró, C.; Espinola, R.; Torrentó, C.; Otero, N.; Rossi, A.; Palau, J.; Soler, A.

    2012-04-01

    The aim of this study is to monitor the decontamination of a site polluted by DNAPLs coming from an automotive industry. The contamination was caused by the poor management of the waste generated by the industrial activity, which was discharged into a seepage pit. As a result, soil contamination was produced in the seepage pit area and a plume of DNAPLs-contaminated groundwater was generated. To recover the original environmental quality, a dual action was proposed: in the first place, the removal of the source of contamination and in the second one, the treatment of the DNAPLs plume. The elimination of the source of contamination consisted on a selective excavation of the seepage pit and an offsite management of the contaminated land. To restore the groundwater quality, a passive treatment system using a permeable reactive barrier (PRB) of zero valent iron (ZVI) was implemented. In order to determine the efficiency of the remediation actions, a chemical, isotopic and hydrogeological control of the main solvents detected in groundwater (perchloroethylene -PCE-, trichloroethene -TCE- and cis-dichloroethylene -cis-DCE-) has been established. Results show a decrease in PCE concentration that has been attributed to the removal of the source more than to a degradation process. However, the presence of PCE by-products, TCE and cis-DCE, might indicate a possible PCE biotic degradation. ?13CPCE values analyzed upstream and downstream of the barrier don't show isotopic changes associated to the PRB (values are around -20‰ in all the sampling points). TCE might have experienced a natural advanced degradation process according to the high concentration of cis-DCE found prior the installation of the PRB and the isotopic enrichment in ?13CTCE in some specific areas of the plume (-19.9‰ in the source and -16‰ before the barrier). Slight isotopic changes have been observed in the water flow in a far distance after the barrier (-15.4‰). ?13Ccis-DCE experienced an enrichment upstream to downstream of the barrier (from -15.5‰ to -11.5‰) indicating that a possible abiotic degradation due to the PRB is being produced. However, an enrichment in ?13Ccis-DCE from the focus area to the barrier (from -19.9‰ to -15.5‰) was also detected, suggesting that biotic degradation of cis-DCE is occurring in the field. As a conclusion, preliminary concentration and isotopic results seem to indicate that the PRB does not intercept the whole contaminated plume. The installation of a monitoring system of multilevel piezometers of new construction around the PRB has been proposed in order to study in detail the underground sections most affected by pollution and help to define patterns of migration of DNAPLs in the subsurface, giving the possibility to improve the design of the ZVI-PRB.

  15. COMMUNICATION TO THE EDITOR Aerobic Degradation of Mixtures of

    E-print Network

    Wood, Thomas K.

    (TCE) INTRODUCTION Both tetrachloroethylene (PCE) and trichloroethylene (TCE) are suspected carcinogens carcinogen (McCarty, 1997). Both VC and cis-DCE are U.S. Environmental Protection Agency priority pollut carcinogen (Mc- Clay et al., 1996). Because of this ecological risk posed by soil and water contaminated

  16. Methods for environmental monitoring of DOE waste disposal and storage sites. Semiannual progress report, April 1, 1988--September 30, 1988

    SciTech Connect

    Hadden, C.T.; Benson, S.B.; Osborne, T.R.; Revis, N.W.

    1988-12-31

    Perchloroethylene (PCE) is a persistent environmental contaminant whose chemical stability and hydrophobicity have made it difficult to remove from contaminated groundwater. PCE is also toxic and has been implicated as a carcinogen. This study was aimed at assessing methods for biological degradation of PCE. As a part of the study, the authors have characterized possible products of the degradation of PCE, and have determined the effects of detergents and solvents on the water solubility of PCE and on the toxic effects of PCE on bacteria. The authors have also isolated PCE-resistant microorganisms from monitoring wells at Y-12. To date all of the PCE-resistant bacteria isolated from the monitoring wells have been of the genus Bacillus. One of these isolates appears to be able to degrade PCE, as indicated by the disappearance of PCE from cultures of growing cells. The organism does not grow on PCE as the sole carbon source, so degradation of the solvent must occur by cometabolism.

  17. Resiliency of Stable Isotope Fractionation (?(13)C and ?(37)Cl) of Trichloroethene to Bacterial Growth Physiology and Expression of Key Enzymes.

    PubMed

    Buchner, Daniel; Behrens, Sebastian; Laskov, Christine; Haderlein, Stefan B

    2015-11-17

    Quantification of in situ (bio)degradation using compound-specific isotope analysis requires a known and constant isotope enrichment factor (?). Because reported isotope enrichment factors for microbial dehalogenation of chlorinated ethenes vary considerably we studied the potential effects of metabolic adaptation to TCE respiration on isotope fractionation (?(13)C and ?(37)Cl) using a model organism (Desulfitobacterium hafniesne Y51), which only has one reductive dehalogenase (PceA). Cells grown on TCE for the first time showed exponential growth until 10(9) cells/mL. During exponential growth, the cell-normalized amount of PceA enzyme increased steadily in the presence of TCE (up to 21 pceA transcripts per cell) but not with alternative substrates (<1 pceA transcript per cell). Cultures initially transferred or subcultivated on TCE showed very similar isotope fractionation, both for carbon (?carbon: -8.6‰ ± 0.3‰ or -8.8‰ ± 0.2‰) and chlorine (?chlorine: -2.7‰ ± 0.3‰) with little variation (0.7‰) for the different experimental conditions. Thus, TCE isotope fractionation by D. hafniense strain Y51 was affected by neither growth phase, pceA transcription, or translation, nor by PceA content per cell, suggesting that transport limitations did not affect isotope fractionation. Previously reported variable ? values for other organohalide-respiring bacteria might thus be attributed to different expression levels of their multiple reductive dehalogenases. PMID:26505909

  18. A small amount of tetrachloroethylene ingestion from drinking water accelerates antigen-stimulated allergic responses.

    PubMed

    Seo, Makoto; Yamagiwa, Takeo; Kobayashi, Ryo; Ikeda, Koji; Satoh, Masahiko; Inagaki, Naoki; Nagai, Hiroichi; Nagase, Hisamitsu

    2008-01-01

    Previously, we observed that tetrachloroethylene (perchloroethylene, PCE) increased histamine release and inflammatory mediator production from antigen-stimulated mast cells. In this study, we examined the enhancing effect of low concentrations of PCE in drinking water on antigen-stimulated allergic responses. After exposure of Wistar rats to PCE in drinking water for 2 or 4 weeks, we performed a passive cutaneous anaphylaxis (PCA) reaction. PCE exposure for 4 weeks enhanced PCA reaction in a dose-dependent manner. In pathological studies, PCE exposure for 2 weeks exacerbated inflammation characterized by infiltration of lymphocytes and accumulation of mast cells around the vessel. Non-purified mast cells (NPMCs) from rats treated with 1mg/L PCE in drinking water for 2 weeks increased antigen-stimulated histamine release. Furthermore, the leukocytes of rats treated with PCE in drinking water for 4 weeks showed increased interleukin (IL)-4 expression. The mechanism of enhancing the PCA reaction is assumed to be that PCE increases IL-4 production and PCE causes T helper (Th) 1/Th2-type helper T-cell imbalance and increases histamine release from excessively accumulated mast cells. The results suggest that the intake of PCE in drinking water, even at a low concentration, leads to the initiation and acceleration of allergic diseases. PMID:18950594

  19. Development of an integrated, in-situ remediation technology. Draft topical report for task No. 9. Part II. Entitled: TCE degradation using non-biological methods, September 26, 1994--May 25, 1996

    SciTech Connect

    Orth, R.G.; McKenzie, D.E.

    1997-04-01

    Contamination in low permeability soils poses a significant technical challenge to in-situ remediation efforts. Poor accessibility to the contaminants and difficulty in delivery of treatment reagents have rendered existing in-situ treatments such as bioremediation, vapor extraction, pump and treat rather ineffective when applied to low permeability soils present at many contaminated sites. The technology is an integrated in-situ treatment in which established geotechnical methods are used to install degradation zones directly in the contaminated soil and electro-osmosis is utilized to move the contaminants back and forth through those zones until the treatment is completed. The use of zero valence iron for reductive dechlorination of aliphatic chlorinated hydrocarbons is currently under investigation by a number of research groups as a potential method of in-situ treatment of contaminated ground water. The reaction appears to involve the transfer of electrons to chloro-aliphatic compounds by the oxidation of zero valence iron to ferrous iron (Fe{sup +2}). Our studies have indicated that this reaction is consistent with those of corrosion, and as such, can be influenced or increased by the presence of small amounts of metals (5% by weight) such as copper, tin, silver, gold and palladium coated on the iron surface. Incomplete coverage of the iron surface with a more electropositive metal results in an open galvanic cell, which increases the oxidation of iron and facilitates and increases the concurrent reduction of trichloroethylene and other chlorinated aliphatic compounds to the corresponding alkenes and alkanes. Our results show that plating more electropositive metals onto certain iron surfaces results in approximately a factor of ten increase in the dechlorination rate of small organochlorine compounds such as TCE.

  20. Compound-specific isotope analysis: Questioning the origins of a trichloroethene plume

    USGS Publications Warehouse

    Eberts, S.M.; Braun, C.; Jones, S.

    2008-01-01

    Stable carbon isotope ratios of trichloroethene (TCE), cis-1,2- dichloroethene, and trans-1,2-dichloroethene were determined by use of gas chromatography-combustion-isotope ratio mass spectroscopy to determine whether compound-specific stable carbon isotopes could be used to help understand the origin and history of a TCE groundwater plume in Fort Worth, TX. Calculated ??13C values for total chlorinated ethenes in groundwater samples, which can approximate the ??13C of a spilled solvent if all degradation products are accounted for, were useful for determining whether separate lobes of the plume resulted from different sources. Most notably, values for one lobe, where tetrachloroethene (PCE) has been detected periodically, were outside the range for manufactured TCE but within the range for manufactured PCE, whereas values for a separate lobe, which is downgradient of reported TCE spills, were within the range for manufactured TCE. Copyright ?? Taylor & Francis Group, LLC.

  1. Novel Analytical Techniques Based on a Enhanced Electron Attachment Process - Final Report - 09/15/1996 - 06/15/2001

    SciTech Connect

    Pinnaduwage, Lal A.; Buchanan, Michelle V.

    2001-06-15

    Present analytical methodologies for the detection of chlorinated compounds important to DOE's environmental restoration program, such as DNAPLs [dense non-aqueous phase liquids - such as carbon tetrachloride, trichloroethylene (TCE), perchloroethylene (PCE)], polychlorinated biphenyls (PCB), and others, involve detection by negative-ion-based analytical techniques. These techniques exploit electron attachment to analyte molecules in their ground electronic states, and are limited to particular compounds with appropriate electron capture cross sections. For example, PCB contamination is detected by analysis of mixtures of chlorinated homologues of these biphenyls. Homologues with lower numbers of chlorines do not efficiently attach thermal electrons and thus are not detected by either electron capture chromatographic detectors or by negative ion chemical ionization mass spectrometry. We proposed three novel analytical techniques based on enhanced negative-ion formation via electron attachment to highly-excited electronic states of molecules. In one of the proposed techniques, the excited states of the (analyte) molecules are populated via laser excitation; the resulting negative ions are mass analyzed for identification. The other two proposed techniques utilize a specialized gas discharge for the formation of excited species (and low-energy electrons for attachment), and thus will provide a cost-effective method if successful. In one version, the negative ions will be mass analyzed -as in the laser-based technique- and in the other, the decrease in electron density due to excited state attachment will be monitored (electron capture detector mode). A plasma mixing scheme will be employed to excite the analyte molecules so that the excited states of the analyte molecules will not be destroyed by the discharge.

  2. A theoretical model of air and steam co-injection to prevent the downward migration of DNAPLs during steam-enhanced extraction.

    PubMed

    Kaslusky, Scott F; Udell, Kent S

    2002-04-01

    When steam is injected into soil containing a dense volatile non-aqueous phase liquid contaminant the DNAPL vaporized within the heated soil region condenses and accumulates ahead of the steam condensation front. If enough DNAPL accumulates, gravitational forces can overcome trapping forces allowing the liquid contaminant to flow downward. By injecting air with steam, a portion of the DNAPL vapor remains suspended in equilibrium with the air, decreasing liquid contaminant accumulation ahead of the steam condensation front, and thus reducing the possibility of downward migration. In this work, a one-dimensional theoretical model is developed to predict the injection ratio of air to steam that will prevent the accumulation of volatile DNAPLs. The contaminated region is modeled as a one-dimensional homogeneous porous medium with an initially uniform distribution of a single component contaminant. Mass and energy balances are combined to determine the injection ratio of air to steam that eliminates accumulation of the contaminant ahead of the steam condensation front, and hence reduces the possibility of downward migration. The minimum injection ratio that eliminates accumulation is defined as the optimum injection ratio. Example calculations are presented for three DNAPLs, carbon tetrachloride (CCl4), trichloroethylene (TCE), and perchloroethylene (PCE). The optimum injection ratio of air to steam is shown to depend on the initial saturation and the volatility of the liquid contaminant. Numerical simulation results are presented to validate the model, and to illustrate downward migration for ratios less than optimum. Optimum injection ratios determined from numerical simulations are shown to be in good agreement with the theoretical model. PMID:11999630

  3. DNAPLs at DOE sites: Background and assessment of characterization technologies

    SciTech Connect

    Junk, G.A.; Haas, W.J. Jr.

    1993-12-01

    The Characterization, Monitoring, and Sensor Technology Integrated Program (CMST-IP) within the Office of Technology Development (OTD) has responsibility for identification, evaluation, and delivery of technologies needed for the work of the Department of Energy`s Office of Environmental Restoration and Waste Management. This report addresses part of that responsibility by providing summary information on DNAPL site characterization. A dense nonaqueous phase liquid (DNAPL) is a source of contamination that can persist in the subsurface for decades before dissipating completely into the vapor phase and groundwater. The DNAPL chemicals of particular concern to the DOE are chlorinated volatile organic compounds (Cl VOCS) such as carbon tetrachloride (CCl{sub 4}), trichloroethylene (TCE), and perchloroethylene (PCE). These Cl VOCs were used in multiple ton quantities at DOE sites and were often released to the subsurface. The predicted fate of released Cl VOC liquid is downward movement through the soil under the force of gravity. As it moves, some of the Cl VOC liquid becomes trapped in the soil pores as residual saturation. The liquid also moves rapidly downward if small fractures are present. This migration continues until an impermeable or semi-permeable layer is encountered. Then lateral movement or spreading occurs. The downward and lateral migration in the subsurface leads to DNAPL pools, lenses, and residual saturation that can cause long-term contamination of groundwater at levels well above drinking water standards. Although Cl VOCs have been detected as dissolved components in the groundwater and as vapor in the soil gas at several DOE sites, direct evidence of their presence as DNAPL is sparse and no measurements of the amounts of DNAPL present within a given volume of subsurface have been made. Consequently, unresolved DNAPL issues exist at DOE sites.

  4. IRIS Toxicological Review of Tetrachloroethylene (Perchloroethylene) (External Review Draft)

    EPA Science Inventory

    EPA conducted a peer review of the scientific basis supporting the human health hazard and dose-response assessment of tetrachloroethylene that will appear on the Integrated Risk Information System (IRIS) database. Peer review is meant to ensure that science is used credibly and ...

  5. Charge to the Tetrachloroethylene (Perchloroethylene) Neurotoxicity Expert Panel

    EPA Science Inventory

    Today NCEA is posting the charge which will be discussed at the expert panel meeting on neurotoxicity issues associated with exposure to tetrachlroroethylene. This charge is to be the main agenda topic for the meeting. The time and place of the meeting will be announced in a fu...

  6. Application of a perchloroethylene medium in coal cleaning

    SciTech Connect

    Vivian, T.A.

    1984-02-01

    The use of heavy media organic solvents to recover coal from its attendant gangue is hardly new. DuPont built a pilot plant using pentachloroethane in 1936 at Weston Coal Company, Weston Breaker, Shenandoah, Pennsylvania. That's almost half a century ago. Since that time, it has become common practice to utilize similar classes of chemicals in laboratory separations of coal samples. It is the objective of this paper to discuss some specific separations on both pilot and laboratory scale on samples representing different classifications of coal.

  7. Dechlorination of TCE with palladized iron

    DOEpatents

    Fernando, Quintus (Tucson, AZ); Muftikian, Rosy (Tucson, AZ); Korte, Nic (Grand Junction, CO)

    1997-01-01

    The present invention relates to various methods, such as an above-ground method and an in-ground method, of using a palladized iron bimetallic system for the dechlorination of chlorinated organic compounds from effluents containing the same. The use of palladized iron bimetallic system results in the dechlorination of the chlorinated organic compound into environmentally safe reaction products. The present invention also provides kits, devices, and other instruments that use the above-mentioned palladized iron bimetallic system for the dechlorination of chlorinated organic compounds.

  8. Dechlorination of TCE with palladized iron

    DOEpatents

    Fernando, Quintus (Tucson, AZ); Muftikian, Rosy (Tucson, AZ); Korte, Nic (Grand Junction, CO)

    1998-01-01

    The present invention relates to various methods, such as an above-ground method and an in-ground method, of using a palladized iron bimetallic system for the dechlorination of chlorinated organic compounds from effluents containing the same. The use of palladized iron bimetallic system results in the dechlorination of the chlorinated organic compound into environmentally safe reaction products. The present invention also provides kits, devices, and other instruments that use the above-mentioned palladized iron bimetallic system for the dechlorination of chlorinated organic compounds.

  9. Dechlorination of TCE with palladized iron

    DOEpatents

    Fernando, Q.; Muftikian, R.; Korte, N.

    1998-06-02

    The present invention relates to various methods, such as an above-ground method and an in-ground method, of using a palladized iron bimetallic system for the dechlorination of chlorinated organic compounds from effluents containing the same. The use of palladized iron bimetallic system results in the dechlorination of the chlorinated organic compound into environmentally safe reaction products. The present invention also provides kits, devices, and other instruments that use the above-mentioned palladized iron bimetallic system for the dechlorination of chlorinated organic compounds. 10 figs.

  10. Dechlorination of TCE with palladized iron

    DOEpatents

    Fernando, Quintus (Tucson, AZ); Muftikian, Rosy (Tucson, AZ); Korte, Nic (Grand Junction, CO)

    1997-01-01

    The present invention relates to various methods, such as an above-ground method and an in-ground method, of using a palladized iron bimetallic system for the dechlorination of chlorinated organic compounds from various effluents or contaminated soil containing the same. The use of palladized iron bimetallic system results in the dechlorination of the chlorinated organic compound into environmentally safe reaction products.

  11. The change of microbial community from chlorinated solvent-contaminated groundwater after biostimulation using the metagenome analysis.

    PubMed

    Kao, Chih-Ming; Liao, Hung-Yu; Chien, Chih-Ching; Tseng, Yi-Kuan; Tang, Petrus; Lin, Chih-En; Chen, Ssu-Ching

    2016-01-25

    The compositions of bacterial community in one site contaminated with PCE/TCE after the slow polycolloid-releasing substrate (SPRS) (contained vegetable oil, cane molasses, and surfactants) addition were analyzed. Results show that SPRS caused a rapid enhancement of reductive dechlorination of TCE. The transformation of PCE/TCE into ethene was observed after 20 days of operation. To compare the change of bacterial communities before and after SPRS addition, 16S rRNA amplicon sequencing using the metagenome analysis was performed. Results demonstrated the detection of the increased amounts of Dehalogenimonas by 2.2-fold, Pseudomonas by 3.4-fold and Sulfuricurvum by 4-fold with the analysis of the ribosomal database project (RDP). Metagenomic DNA was extracted from PCE/TCE-contaminated groundwater after SPRS addition, and subjected to sequencing. Results obtained from metagenomic sequencing indicate that genes from Dehalococcoides mccartyi was ranked as the second abundant bacteria among all of the detected bacteria via the analysis of the lowest common ancestor (LCA). Abundance of these bacterial groups, as shown above suggests their role in TCE biodegradation. Functional analysis of the metagenome, with the specific reference to chloroalkane and chloroalkene degradation, revealed the presence of some genes responsible for TCE biodegradation. Overall, results of this study provided new insights for a better understanding of the potential of biostimulation on TCE-contaminated sites. PMID:26474376

  12. Reductive dechlorination of chlorinated ethene DNAPLs by a culture enriched from contaminated groundwater

    SciTech Connect

    Nielsen, R.B.; Keasling, J.D.

    1999-01-20

    A microbial culture enriched from a trichloroethene-contaminated groundwater aquifer reductively dechlorinated trichloroethene (TCE) and tetrachloroethene (PCE) to ethene. Initial PCE dechlorination rate studies indicated a first-order dependence with respect to substrate at low PCE concentrations, and a zero-order dependence at high concentrations. Studies of TCE and vinyl chloride (VC) dechlorination indicated a first-order dependence at all substrate concentrations. VC had little or no effect on the initial rate of TCE dechlorination. With subsaturating concentrations of chlorinated ethenes, nearly stoichiometric amounts of the toxic intermediate vinyl chloride accumulated prior to its dechlorination to ethene. In contrast, under saturating conditions, in which a dense, nonaqueous-phase liquid existed in equilibrium with the aqueous phase, the chlorinated ethene was dechlorinated to ethene, at a rapid rate, with the accumulation of relatively small amounts of chlorinated intermediates.

  13. Human Health Effects of Tetrachloroethylene: Key Findings and Scientific Issues

    PubMed Central

    Hogan, Karen A.; Scott, Cheryl Siegel; Cooper, Glinda S.; Bale, Ambuja S.; Kopylev, Leonid; Barone, Stanley; Makris, Susan L.; Glenn, Barbara; Subramaniam, Ravi P.; Gwinn, Maureen R.; Dzubow, Rebecca C.; Chiu, Weihsueh A.

    2014-01-01

    Background: The U.S. Environmental Protection Agency (EPA) completed a toxicological review of tetrachloroethylene (perchloroethylene, PCE) in February 2012 in support of the Integrated Risk Information System (IRIS). Objectives: We reviewed key findings and scientific issues regarding the human health effects of PCE described in the U.S. EPA’s Toxicological Review of Tetrachloroethylene (Perchloroethylene). Methods: The updated assessment of PCE synthesized and characterized a substantial database of epidemiological, experimental animal, and mechanistic studies. Key scientific issues were addressed through modeling of PCE toxicokinetics, synthesis of evidence from neurological studies, and analyses of toxicokinetic, mechanistic, and other factors (tumor latency, severity, and background rate) in interpreting experimental animal cancer findings. Considerations in evaluating epidemiological studies included the quality (e.g., specificity) of the exposure assessment methods and other essential design features, and the potential for alternative explanations for observed associations (e.g., bias or confounding). Discussion: Toxicokinetic modeling aided in characterizing the complex metabolism and multiple metabolites that contribute to PCE toxicity. The exposure assessment approach—a key evaluation factor for epidemiological studies of bladder cancer, non-Hodgkin lymphoma, and multiple myeloma—provided suggestive evidence of carcinogenicity. Bioassay data provided conclusive evidence of carcinogenicity in experimental animals. Neurotoxicity was identified as a sensitive noncancer health effect, occurring at low exposures: a conclusion supported by multiple studies. Evidence was integrated from human, experimental animal, and mechanistic data sets in assessing adverse health effects of PCE. Conclusions: PCE is likely to be carcinogenic to humans. Neurotoxicity is a sensitive adverse health effect of PCE. Citation: Guyton KZ, Hogan KA, Scott CS, Cooper GS, Bale AS, Kopylev L, Barone S Jr, Makris SL, Glenn B, Subramaniam RP, Gwinn MR, Dzubow RC, Chiu WA. 2014. Human health effects of tetrachloroethylene: key findings and scientific issues. Environ Health Perspect 122:325–334;?http://dx.doi.org/10.1289/ehp.1307359 PMID:24531164

  14. Bubbleless gas transfer technology for the in situ remediation of chlorinated hydrocarbons

    SciTech Connect

    Gallagher, J.R.; Kurz, M.D.

    1999-10-31

    The primary objective of this project is to demonstrate the ability of hydrogen to supply reducing equivalents for the reductive dehalogenation of perchloroethylene (PCE). This objective will be accomplished by two types of activities. First, laboratory experiments will compare the kinetics of hydrogen-mediated dehalogenation with natural routes of loss (hydrolysis and natural attenuation). Secondly, bench-scale column experiments will be performed to demonstrate hydrogen-mediated reductive dehalogenation in aquifer sediments.

  15. Comparison of Chlorinated Ethenes DNAPL Reductive Dechlorination by Indigenous and Evanite culture with Surfactant Tween-80

    NASA Astrophysics Data System (ADS)

    Kwon, S.; Hong, S.; Kim, R.; Kim, N.; Ahn, H.; Lee, S.; Kim, Y.

    2010-12-01

    Although many innovative technologies have been developed to enhance remediation of chlorinated ethenes(e.g. tetrachloroethene[PCE], trichloroethene[TCE])DNAPL source zones, they have been ineffective in reducing contaminant concentration to regulatory end points. Thus, combination of surfactant flushing process that removes significant contaminant mass with microbial reductive dechlorination, posttreatment "polishing step" to control the remaining DNAPL that may serve as a source of reducing equivalents and stimulate the dechlorinating bacterial communities may be an attractive remediation process alternatively. Microcosm studies were conducted to explore chlorinated ethenes, PCE/TCE of 3 ~ 30 mg/L dechlorination by indigenous microbial communities from TCE DNAPL source zones of Korea and Evanite culture in the presence of Tween-80 of 10 ~ 5,000 mg/L. In the microcosms for indigenous microbial communities, by-products(e.g. c-DCE, vinyl chloride) of reductive dechlorination of PCE/TCE were not detected. This results suggest dechlorinating bacteria might be not exist or high concentration of chlorinated ethenes inhibit activity of dechlorinating bacteria in indigenous microbial communities. But VFAs like acetate, methane and hydrogen gas from fermentation of Tween-80 were detected. So Tween-80 might estimated to serve as a source of reducing equivalents. To evaluate the dechlorinating ability of Evanite-culture, we added Evanite-culture to the microcosms for indigenous bacteria and monitored by-products of reductive dechlorination of PCE/TCE and VFAs and hydrogen gas.

  16. CONCURRENT INJECTION OF COSOLVENT AND AIR FOR ENHANCED PCE REMOVAL

    EPA Science Inventory

    The goal of this study was to use preferential flow of air to improve the dynamics of cosolvent displacement in order to enhance DNAPL displacement and dissolution. The concurrent injection of cosolvent and air was evaluated in a glass micromodel for a DNAPL remediation technolog...

  17. Comparative simulation studies of plasma cathode electron (PCE) gun

    NASA Astrophysics Data System (ADS)

    Prajapati, Jitendra; Pal, U. N.; Kumar, Niraj; Verma, D. K.; Prakash, Ram; Srivastava, V.

    2012-05-01

    Pseudospark discharge based plasma cathode has capability to provide high current density electron beam during discharge process. In this paper an effort has been made to simulate the breakdown processes in the pseudospark discharge based plasma cathode electron gun. The two-dimensional plasma simulation codes VORPAL and OOPIC-Pro have been used and results are compared. The peak discharge current in the plasma cathode electron gun is found to be dependent on aperture size, hollow cathode dimensions, anode voltage and seed electrons energy. The effect of these design parameters on the peak anode current has been analysed by both the codes and results matches well within 10% variation. For the seed electron generation an electron beam trigger source is used to control the discharge process in the hollow cathode cavity. The time span of trigger source has been varied from 1-100 ns to analyze the effect on the peak anode current.

  18. Dual carbon-chlorine stable isotope investigation of sources and fate of chlorinated ethenes in contaminated groundwater.

    PubMed

    Wiegert, Charline; Aeppli, Christoph; Knowles, Tim; Holmstrand, Henry; Evershed, Richard; Pancost, Richard D; Machá?ková, Ji?ina; Gustafsson, Örjan

    2012-10-16

    Chlorinated ethenes (CEs) are ubiquitous groundwater contaminants, yet there remains a need for a method to efficiently monitor their in situ degradation. We report here the first field application of combined stable carbon and chlorine isotope analysis of tetrachloroethene (PCE) and trichloroethene (TCE) to investigate their biodegradation in a heavily contaminated aquifer. The two-dimensional Compound Specific Isotope Analysis (2D-CSIA) approach was facilitated by a recently developed gas chromatography-quadrupole mass spectrometry (GCqMS) method for ?(37)Cl determination. Both C and Cl isotopes showed evidence of ongoing PCE transformation. Applying published C isotope enrichment factors (?(C)) enabled evaluation of the extent of in situ PCE degradation (11-78%). We interpreted C and Cl isotopes using a numerical reactive transport model along a 60-m flow path. It revealed that combined PCE and TCE mass load was dechlorinated by less than 10%, and that cis-dichloroethene was not further dechlorinated. Furthermore, the 2D-CSIA approach allowed estimation of Cl isotope enrichment factors ?(Cl) (-7.8 to -0.8‰) and characteristic ?(Cl)/?(C) values (0.42-1.12) for reductive PCE dechlorination at this field site. This investigation demonstrates the benefit of 2D-CSIA to assess in situ degradation of CEs and the applicability of Cl isotope fractionation to evaluate PCE and TCE dechlorination. PMID:22989309

  19. Bio-reduction of tetrachloroethen using a H2-based membrane biofilm reactor and community fingerprinting.

    PubMed

    Karata?, Serdar; Hasar, Halil; Ta?kan, Ergin; Özkaya, Bestamin; ?ahinkaya, Erkan

    2014-07-01

    Chlorinated ethenes in drinking water could be reductively dechlorinated to non-toxic ethene by using a hydrogen based membrane biofilm reactor (H2-MBfR) under denitrifying conditions as it provides an appropriate environment for dechlorinating bacteria in biofilm communities. This study evaluates the reductive dechlorination of perchloroethene (PCE) to non-toxic ethene (ETH) and comparative community analysis of the biofilm grown on the gas permeable membrane fibers. For these purposes, three H2-MBfRs receiving three different chlorinated ethenes (PCE, TCE and DCE) were operated under different hydraulic retention times (HRTs) and H2 pressures. Among these reactors, the H2-MBfR fed with PCE (H2-MBfR 1) accomplished a complete dechlorination, whereas cis-DCE accumulated in the TCE receiving H2-MBfR 2 and no dechlorination was detected in the DCE receiving H2-MBfR 3. The results showed that 95% of PCE dechlorinated to ETH together with over 99.8% dechlorination efficiency. Nitrate was the preferred electron acceptor as the most of electrons generated from H2 oxidation used for denitrification and dechlorination started under nitrate deficient conditions at increased H2 pressures. PCR-DGGE analysis showed that Dehalococcoides were present in autotrophic biofilm community dechlorinating PCE to ethene, and RDase genes analysis revealed that pceA, tceA, bvcA and vcrA, responsible for complete dechlorination step, were available in Dehalococcoides strains. PMID:24731873

  20. RELATIONSHIP BETWEEN GEOCHEMICAL PARAMETERS AND THE OCCURRENCE OF DEHALOCOCCOIDES DNA IN CONTAMINATED AQUIFERS

    EPA Science Inventory

    Stains of Dehalococcoides are the only microbes known that can completely dechlorinate PCE, TCE, cis-DCE and vinyl chloride to ethylene. Either naturally-occurring strains or bioaugmentation cultures of Dehalococcoides are widely used for in situ bioremediation ...

  1. EFFECT OF FENTON'S REAGENT ON SUBSURFACE MICROBIOLOGY AND BIODEGRADATION CAPACITY

    EPA Science Inventory

    Microcosm studies were conducted to determine the effect of Fenton's reagent on subsurface microbiology and biodegradation capacity in a DNAPL (PCE/TCE) contaminated aquifer previously treated with the reagent. Groundwater pH declined from 5 to 2.4 immediately after the treatmen...

  2. Natural Attenuation of Chlorinated Solvents and Fuel Components (BTEX and MTBE) in Ground Water

    EPA Science Inventory

    Monitored Natural Attenuation is widely used in the USA to deal with ground water contamination from fuel components such as the BTEX compounds or MTBE or TBA and from chlorinated solvents such as PCE, TCE, and TCA. This presentation reviews the theory and practice of MNA in the...

  3. DNAPL source control by reductive dechlorination with iron-based degradative solidification/stabilization 

    E-print Network

    Do, Si Hyun

    2009-05-15

    by compounds that are formed by reaction of ferrous iron with components of Portland cement or with defined chemicals (FeCl3 + Ca(OH)2). These dechlorinating agents can effectively degrade chlorinated hydrocarbons (PCE, TCE, and 1,1,1-TCA) that are dissolved...

  4. Reduction of Vinyl Chloride in Metallic Iron-Water Systems

    E-print Network

    Deng, Baolin

    Reduction of Vinyl Chloride in Metallic Iron-Water Systems B A O L I N D E N G * Department metallic iron as the source of electrons for reductive dechlorination has been proposed and successfully- tion of PCE (21), TCE (16, 22-24), and cis- and trans-1,2- dichloroethylenes (25, 26) in metallic iron-water

  5. Hydrodechlorination of Trichloroethylene to Hydrocarbons Using Bimetallic Nickel-Iron

    E-print Network

    tetrachloride), PCE (tetrachloroethylene), and TCE (trichloroethylene), in groundwater and surface waters. A concentration of only a few parts per million (ppm) of these possible carcino- gens in water supplies requires the overall design of metal-based treatment systems.4,7-10,17 Since the dechlorination reaction of halogenated

  6. NGWA.org Ground Water Monitoring & Remediation 00, no. 0/ xxxx 0000/pages 0000 1 2012, The Author(s)

    E-print Network

    Clement, Prabhakar

    NGWA.org Ground Water Monitoring & Remediation 00, no. 0/ xxxx 0000/pages 00­00 1 © 2012, The Author(s) Ground Water Monitoring & Remediation © 2012, National Ground Water Association. doi: 10.1111/j anaerobic degrada- tion, PCE and TCE are reductively dechlorinated to form cis-DCE, VC, and the end product

  7. Chloroethene degradation and expression of Dehalococcoides dehalogenase genes in cultures originating from Yangtze sediments.

    PubMed

    Kranzioch, Irene; Ganz, Selina; Tiehm, Andreas

    2015-02-01

    The anaerobic Dehalococcoides spp. is the only microorganism known to completely dechlorinate the hazardous compounds tetrachloroethene (PCE) or trichloroethene (TCE) via dichloroethene (DCE) and vinyl chloride (VC) to the terminal product, ethene. In this study, growth of Dehalococcoides spp. (DHC) and the expression of DHC dehalogenase genes were demonstrated for Yangtze enrichment cultures. Reductive dechlorination of chloroethenes occurred in Yangtze sediment without the addition of any external auxiliary substrates. All Yangtze enrichment cultures completely dechlorinated PCE and cis-DCE to ethene. To investigate expression of the dehalogenase genes pceA, tceA, vcrA, and bvcA, a protocol for messenger RNA (mRNA) extraction followed by reverse transcription and quantitative PCR analysis was established. During dechlorination, an increase in gene copy numbers of pceA, tceA, and vcrA was observed. However, temporary formation of mRNA was only measured in the case of the dehalogenase genes tceA and vcrA. Comparison of DHC dehalogenase patterns indicated that the Yangtze DHC community does not match any of the previously published enrichment cultures that were obtained from contaminated areas in the USA or Europe. PMID:25233916

  8. 77 FR 40318 - Availability of Addendum to Documentation Supporting the Proposal of the Leeds Metal Site to the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-09

    ... data review by the EPA at the time of proposal (76 FR 57702, September 16, 2011). The targets factor... at proposal (see 76 FR 57702, September 16, 2011). Background on TCE and PCE Benchmarks and Toxicity... the Leeds Metal Site to the National Priorities List AGENCY: Environmental Protection Agency....

  9. Degradation of Perchloroethene by zero-valent iron evaluated by carbon isotope fractionation

    NASA Astrophysics Data System (ADS)

    Leitner, Simon; Watzinger, Andrea; Reichenauer, Thomas G.

    2014-05-01

    Perchloroethene (PCE) is a widely spread groundwater contaminant in formally used industrial sites. Zero valent iron (ZVI) is used for in situ chemical reduction (ISCR) of PCE contaminants in the groundwater. A key factor in the application of in situ remediation technologies is a proper monitoring of contaminant reduction. The measurement of the stable isotope ratio is a promising method that is already used for quantifying microbial degradation of chlorinated contaminants. The carbon isotope ratio of PCE, measured by - isotope ratio mass spectrometry coupled to a gas chromatograph via a combustion interface (GC-C-IRMS), increases during degradation of PCE and can be directly related to the degree of degradation. It can be used to directly quantify chemical degradation and thus serves as a useful monitoring tool for groundwater remediation. An experiment to determine the carbon isotopic fractionation factor was performed as a lab experiment using Nanofer Star (NANOIRON). Two different PCE concentrations (c1: 220mgL-1, c2: 110mgL-1) mixed with 0.5 g of ZVI were sealed under deoxygenated conditions in 250 ml glas bottles locked with mininert caps. The bottles were incubated on a shaker for 865 h. Samples were taken weekly to measure the change in the carbon isotopic ratio of PCE as well as its concentration. Results showed a strong increase in the carbon isotope ratio (?-value) of PCE (start: -27 o end: -4 ), which indicates a significant dechlorination process of PCE. Beside PCE also one degradation product (Trichloroethylene - TCE) was measured. TCE was further dechlorinated as indicated by the ?-value change of TCE from -26 o to -4 oȦn unexpected intermediate value of -45 o for TCE was observed in the experiment. This fluctuation could be induced by the time depending concentration due to degradation and conversation processes. Furthermore, it seems that the progress of the ?-value is affected by the starting concentration of PCE (?-value of c1 < c2) as there is a higher ratio of PCE to ZVI.

  10. Dechlorination of chlorinated hydrocarbons by bimetallic Ni/Fe immobilized on polyethylene glycol-grafted microfiltration membranes under anoxic conditions.

    PubMed

    Parshetti, Ganesh K; Doong, Ruey-an

    2012-01-01

    In this study, the dechlorination of chlorinated hydrocarbons including trichloroethylene (TCE), tetrachloroethylene (PCE) and carbon tetrachloride (CT) by bimetallic Ni/Fe nanoparticles immobilized on four different membranes was investigated under anoxic conditions. Effects of several parameters including the nature of membrane, initial concentration, pH value, and reaction temperature on the dechlorination efficiency were examined. The scanning electron microscopic images showed that the Ni/Fe nanoparticles were successfully immobilized inside the four membranes using polyethylene glycol as the cross-linker. The agglomeration of Ni/Fe were observed in poly(vinylidene fluoride), Millex GS and mixed cellulose ester membranes, while a relatively uniform distribution of Ni/Fe was found in nylon-66 membrane because of its hydrophilic nature. The immobilized Ni/Fe nanoparticles exhibited good reactivity towards the dechlorination of chlorinated hydrocarbons, and the pseudo-first-order rate constant for TCE dechlorination by Ni/Fe in nylon-66 were 3.7-11.7 times higher than those in other membranes. In addition, the dechlorination efficiency of chlorinated hydrocarbons followed the order TCE>PCE>CT. Ethane was the only end product for TCE and PCE dechlorination, while dichloromethane and methane were found to be the major products for CT dechlorination, clearly indicating the involvement of reactive hydrogen species in dechlorination. In addition, the initial rate constant for TCE dechlorination increased upon increasing initial TCE concentrations and the activation energy for TCE dechlorination by immobilized Ni/Fe was 34.9 kJ mol(-1), showing that the dechlorination of TCE by membrane-supported Ni/Fe nanoparticles is a surface-mediated reaction. PMID:22115467

  11. Electrical impedance tomography of the 1995 OGI perchloroethelyne release

    SciTech Connect

    Dailey, W.; Ramirez, A.

    1996-10-01

    Goal is to determine if electrical impedance tomography (EIT) might be useful to map free product DNAPL (dense nonaqueous phase liquids) contamination. EIT was used to image the plume resulting from a release of 189 liters (50 gallons) of perchloroethylene (PCE) into a saturated aquifer constructed of sand with two layers of bentonite. Images were made in 4 planes, before, during, and after the release, to generate a detailed picture of the spatial and temporal development of the plume. Information of the EI (both in phase and out of phase voltages) was used at several different frequencies to produce images. Some frequency dispersion was observed in the images before and after the PCE release. Laboratory measurements of organic contamination in soil indicate detectable dispersion. A search for this effect in EIT images reveals weak evidence, the signal appearing just above the measurement uncertainty, of a change in the reactance in the soil because of the PCE.

  12. Control and remediation of solvent pollution in the dry cleaning industry: A technological assessment

    SciTech Connect

    Johnston, J.R.; Hanna, G.P. Jr.; Tchobanoglous, G.

    1996-11-01

    PCE (perchloroethylene) is classified as a toxic air pollutant and it has been found in groundwater in many locations. Dry cleaning establishments have been identified as a source of fugitive atmospheric emissions and it is thought that dry cleaners are an important contributor to groundwater contamination in many locations. Recognizing the environmental problems associated with the dry cleaning industry, the California legislature enacted Assembly Bill 2370 in 1992, which created the California Dry Cleaning Industry Task Force. A technical background report on the pollution problems of California`s dry cleaning industry was prepared for the Task Force by researchers from California State University Fresno and the University of California, Davis. This paper is extracted from that report. The paper discusses the dry cleaning process and equipment, potential sources of PCE pollution, source controls, remediation of historical pollution, and prevention of future PCE pollution.

  13. Partition behavior of surfactants, butanol, and salt during application of density-modified displacement of dense non-aqueous phase liquids.

    PubMed

    Damrongsiri, S; Tongcumpou, C; Sabatini, D A

    2013-03-15

    Density-modified displacement (DMD) is a recent approach for removal of trapped dense NAPL (DNAPL). In this study, butanol and surfactant are contacted with the DNAPL to both reduce the density as well as release the trapped DNAPL (perchloroethylene: PCE). The objective of the study was to determine the distribution of each component (e.g., butanol, surfactant, water, PCE) between the original aqueous and PCE phases during the application of DMD. The results indicated that the presence of the surfactant increased the amount of n-butanol required to make the NAPL phase reach its desired density. In addition, water and anionic surfactant were found to partition along with the BuOH into the PCE phase. The water also found partitioned to reverse micelles in the modified phase. Addition of salt was seen to increase partitioning of surfactant to BuOH containing PCE phase. Subsequently, a large amount of water was solubilized into reverse micelles which lead to significantly increase in volume of the PCE phase. This work thus demonstrates the role of each component and the implications for the operation design of an aquifer treatment using the DMD technique. PMID:23385206

  14. Removal of DNAPL contamination from the saturated zone by the combined effect of vertical upward flushing and density reduction.

    PubMed

    Hofstee, C; Gutiérrez Ziegler, C; Trötschler, O; Braun, J

    2003-12-01

    A common aspect of innovative remediation techniques is that they tend to reduce the interfacial tension between the aqueous and non-aqueous phase liquids, resulting in mobilization of the organic contaminant. This complicates the remediation of aquifers, contaminated with Dense Non-Aqueous Phase Liquids (DNAPLs), as they are likely to migrate downwards, deeper into the aquifer and into finer layers. A possible solution is the use of swelling alcohols, which tend to reduce the density difference between the aqueous phase and the DNAPL. To avoid premature mobilization upon the initial contact between the DNAPL and the alcohol, several researchers have proposed the use of vertical upward flow of the alcohol. In this paper, we present an equation, which describes the upward mobilization of both continuous and discontinuous DNAPLs and so the important parameters governing the upward controlled mobilization of the DNAPL. The need and required magnitude of this specific discharge was investigated by conducting four column experiments in which the initial density of the DNAPL and the permeability was varied. It was shown that the required flow velocities increase with the permeability of the porous medium and the initial density difference between the aqueous phase and the DNAPL. Whenever the specific discharge falls below the critical value, the DNAPL moves downward. A second set of column experiments looked at the impact of permeability of porous medium on the solubilization and mobilization of DNAPL during alcohol flooding. Columns, packed with coarse or fine sand, containing a residual trichloroethylene (TCE) or perchloroethylene (PCE) saturation were flushed with the alcohol mixture at a fixed specific discharge rate. The induced pressure gradients in the aqueous phase, which were higher in the fine sand, resulted for this porous medium in extensive mobilization of the DNAPL against the direction of the buoyancy force. The density of the first NAPL coming out of the top of the fine sand was close to that of the pure DNAPL. In the coarser sand, the pressure gradients were sufficient to prevent downward migration of the DNAPL, but upward mobilization was minimal. The predominant removal mechanism in this case was the much slower solubilization. PMID:14607470

  15. Interplay between subsurface structural heterogeneity and multi-species reactive transport in human health risk predictions

    NASA Astrophysics Data System (ADS)

    Henri, C.; Fernandez-Garcia, D.; de Barros, F.

    2013-12-01

    The increasing presence of toxic chemicals released in the subsurface has led to a rapid growth of social concerns and to the need to develop and employ models that can predict the impact of groundwater contamination in human health under uncertainty. Monitored natural attenuation is a common remediation action in many contamination cases and represents an attractive decontamination method. However, natural attenuation can lead to the production of subspecies of distinct toxicity that may pose challenges in pollution management strategies. The actual threat that these contaminants pose to human health and ecosystems greatly depends on the interplay between the complexity of the geological system and the toxicity of the pollutants and their byproducts. In this work, we examine the interplay between multispecies reactive transport and the heterogeneous structure of the contaminated aquifer on human health risk predictions. The structure and organization of hydraulic properties of the aquifer can lead to preferential flow channels and fast contamination pathways. Early travel times, associated to channeling effects, are intuitively perceived as an indicator for high risk. However, in the case of multi-species systems, early travel times may also lead a limited production of daughter species that may contain higher toxicity as in the case of chlorinated compounds. In this work, we model a Perchloroethylene (PCE) contamination problem followed by the sequential first-order production/biodegradation of its daughter species Trichloroethylene (TCE), Dichloroethylene (DCE) and Vinyl Chlorine (VC). For this specific case, VC is known to be a highly toxic contaminant. By performing numerical experiments, we evaluate transport for two distinct three-dimensional aquifer structures. First, a multi-Gaussian hydraulic conductivity field and secondly, a geostatistically equivalent connected field. These two heterogeneity structures will provide two distinct ranges of mean travel times and other higher order statistics. Uncertainty on the hydraulic conductivity field is considered through a Monte Carlo scheme, and the total risk (TR) for human health related to the mixtures of the four carcinogenic plumes is evaluated. Results show two distinct spatio-temporal behavior of the TR estimation. At a fixed environmentally sensitive location, aquifers with a high degree of connectivity display a lower TR. On the other hand, at the same environmentally sensitive location, the poorly connected aquifer yields higher TR. Our results reflect the interplay between the characteristic reactive time for each component and the characteristic travel time of the plume since the production of VC depends on these factors.

  16. Reductive dechlorination of tetrachloroethylene and trichloroethylene catalyzed by vitamin B{sub 12} in homogeneous and heterogeneous systems

    SciTech Connect

    Burris, D.R.; Smith, M.H.; Delcomyn, C.A.; Roberts, A.L.

    1996-10-01

    The reduction of tetrachloroethylene (PCE) and trichloroethylene (TCE) catalyzed by vitamin B{sub 12} was examined in homogeneous and heterogeneous (B{sub 12} bound to agarose) batch systems using titanium(III) citrate as the bulk reductant. The solution and surface-mediated reaction rates at similar B{sub 12} loadings were comparable, indicating that binding vitamin B{sub 12} to a surface did not lower catalytic activity. No loss in PCE reducing activity was observed with repeated usage of surface-bound vitamin B{sub 12}. Carbon mass recoveries were 81-84% for PCE reduction and 89% for TCE reduction, relative to controls. In addition to sequential hydrogenolysis, a second competing reaction mechanism for the reduction of PCE and TCE by B{sub 12}, reductive {beta}-elimination, is proposed to account for the observation of acetylene as a significant reaction intermediate. Reductive {beta}-elimination should be considered as a potential pathway in other reactive systems involving the reduction of vicinal polyhaloethenes. Surface-bound catalysts such as vitamin B{sub 12} may have utility in the engineered degradation of aqueous phase chlorinated ethenes. 19 refs., 6 figs., 1 tab.

  17. TCE REMOVAL FROM CONTAMINATED SOIL AND GROUND WATER

    EPA Science Inventory

    Widespread use of trichloroethylene (TEE) in the U.S. has resulted in its frequent detection in soil and groundwater. EE can become a health hazard after being processed in the human liver; or reductive dehalogenation in the environment may result in production of vinyl chloride,...

  18. TRANSPORT OF TRICHLOROETHYLENE (TCE) IN NATURAL SOIL BY ELECTROOSMOSIS

    EPA Science Inventory

    Contamination in low permeability soils poses a significant technical challenge to in-situ remediation, primarily due to low mobilization of the contaminants and difficulty in uniform delivery of treatment reagents. An alternative approach using electroosmosis (EO) is used to mob...

  19. Mixed redox catalytic destruction of chlorinated solvents in soils and groundwater.

    PubMed

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

    2008-10-01

    A new thermocatalytic method to destroy chlorinated solvents has been developed in the laboratory and tested in a pilot field study. The method employs a conventional Pt/Rh catalyst on a ceramic honeycomb. Reactions proceed at moderate temperatures in the simultaneous presence of oxygen and a reductant (mixed redox conditions) to minimize catalyst deactivation. In the laboratory, stable operation with high conversions (above 90% at residence times shorter than 1 s) for perchloroethylene (PCE) is achieved using hydrogen as the reductant. A molar ratio of H(2)/O(2)= 2 yields maximum conversions; the temperature required to produce maximum conversions is sensitive to influent PCE concentration. When a homologous series of aliphatic alkanes is used to replace hydrogen as the reductant, the resultant mixed redox conditions also produce high PCE conversions. It appears that the dissociation energy of the C-H bond in the respective alkane molecule is a strong determinant of the activation energy, and therefore the reaction rate, for PCE conversion. This new method was employed in a pilot field study in Tucson, Arizona. The mixed redox system was operated semicontinuously for 240 days with no degradation of catalyst performance and complete destruction of PCE and trichloroethylene in a soil vapor extraction gas stream. Use of propane as the reductant significantly reduced operating costs. Mixed redox destruction of chlorinated solvents provides a potentially viable alternative to current soil and groundwater remediation technologies. PMID:18991945

  20. Prenatal and Early Childhood Exposure to Tetrachloroethylene and Adult Vision

    PubMed Central

    Getz, Kelly D.; Janulewicz, Patricia A.; Rowe, Susannah; Weinberg, Janice M.; Winter, Michael R.; Martin, Brett R.; Vieira, Veronica M.; White, Roberta F.

    2012-01-01

    Background: Tetrachloroethylene (PCE; or perchloroethylene) has been implicated in visual impairments among adults with occupational and environmental exposures as well as children born to women with occupational exposure during pregnancy. Objectives: Using a population-based retrospective cohort study, we examined the association between prenatal and early childhood exposure to PCE-contaminated drinking water on Cape Cod, Massachusetts, and deficits in adult color vision and contrast sensitivity. Methods: We estimated the amount of PCE that was delivered to the family residence from participants’ gestation through 5 years of age. We administered to this now adult study population vision tests to assess acuity, contrast sensitivity, and color discrimination. Results: Participants exposed to higher PCE levels exhibited lower contrast sensitivity at intermediate and high spatial frequencies compared with unexposed participants, although the differences were generally not statistically significant. Exposed participants also exhibited poorer color discrimination than unexposed participants. The difference in mean color confusion indices (CCI) was statistically significant for the Farnsworth test but not Lanthony’s D-15d test [Farnsworth CCI mean difference = 0.05, 95% confidence interval (CI): 0.003, 0.10; Lanthony CCI mean difference = 0.07, 95% CI: –0.02, 0.15]. Conclusions: Prenatal and early childhood exposure to PCE-contaminated drinking water may be associated with long-term subclinical visual dysfunction in adulthood, particularly with respect to color discrimination. Further investigation of this association in similarly exposed populations is necessary. PMID:22784657

  1. A review of potential neurotoxic mechanisms among three chlorinated organic solvents

    SciTech Connect

    Bale, Ambuja S. Barone, Stan; Scott, Cheryl Siegel; Cooper, Glinda S.

    2011-08-15

    The potential for central nervous system depressant effects from three widely used chlorinated solvents, trichloroethylene (TCE), perchloroethylene (PERC), and dichloromethane (DCM), has been shown in human and animal studies. Commonalities of neurobehavioral and neurophysiological changes for the chlorinated solvents in in vivo studies suggest that there is a common mechanism(s) of action in producing resultant neurotoxicological consequences. The purpose of this review is to examine the mechanistic studies conducted with these chlorinated solvents and to propose potential mechanisms of action for the different neurological effects observed. Mechanistic studies indicate that this solvent class has several molecular targets in the brain. Additionally, there are several pieces of evidence from animal studies indicating this solvent class alters neurochemical functions in the brain. Although earlier evidence indicated that these three chlorinated solvents perturb the lipid bilayer, more recent data suggest an interaction between several specific neuronal receptors produces the resultant neurobehavioral effects. Collectively, TCE, PERC, and DCM have been reported to interact directly with several different classes of neuronal receptors by generally inhibiting excitatory receptors/channels and potentiating the function of inhibitory receptors/channels. Given this mechanistic information and available studies for TCE, DCM, and PERC, we provide hypotheses on primary targets (e.g. ion channel targets) that appear to be most influential in producing the resultant neurological effects. - Research Highlights: > Comparison of neurological effects among TCE, PERC, and DCM. > Correlation of mechanistic findings to neurological effects. > Data support that TCE, PERC, and DCM interact with several ion channels to produce neurological changes.

  2. Plasma remediation of perchloroethylene in humid gas streams Ann C. Gentilea)and Mark J. Kushnerb)

    E-print Network

    Kushner, Mark

    to dispose of since it is nearly insoluble in water, nonflammable, and miscible in alcohol, ether, and other- dependent heavy particle reaction rate coefficients to produce species densities as a function of time

  3. Subchronic toxicity of tetrachloroethylene (perchloroethylene) administered in the drinking water of rats

    SciTech Connect

    Hayes, J.R.; Condie, L.W. Jr.; Borzelleca, J.F.

    1986-07-01

    This study provides data on the effects of tetrachloroethylene in drinking solutions. The acute oral LD50 in male and female Charles River rats was found to be 3835 mg/kg for males and 3005 mg/kg for females. Male and female rats received theoretical daily doses of 14,400, and 1400 mg tetrachloroethylene/kg body wt/day for 90 consecutive days. There were no compound-related deaths. Body weights were significantly lower in male and female rats at the higher doses. There were no consistent dose-related effects on any of the hematological, clinical chemistry, or urinalysis parameters. 5'-Nucleotidase activity was increased in a dose-dependent manner, suggesting possible hepatotoxicity; however, other serum indicators of hepatic function were unaffected by the treatment. There were no gross pathological effects observed. Liver and kidney body weight ratios, but not brain weight ratios, were elevated at the higher doses. There was no other evidence of compound-related toxicity. These data suggest that exposure of humans to reported levels of tetrachloroethylene in drinking water (approximately 1 microgram/liter) does not constitute a serious health hazard.

  4. SUBCHRONIC TOXICITY OF TETRACHLOROETHYLENE (PERCHLOROETHYLENE) ADMINISTERED IN THE DRINKING WATER OF RATS

    EPA Science Inventory

    The study provides data on the effects of tetrachloroethylene in drinking solutions. The acute oral LD(50) was determined in male and female Charles River rats and found to be 3835 mg/kg for males and 3005 mg/kg for females. Male and female rats received theoretical daily doses o...

  5. Degradation of perchloroethylene and nitrate by high-activity modified green rusts 

    E-print Network

    Choi, Jeong Yun

    2006-10-30

    that GRs could reductively degrade a number of organic and inorganic contaminants, including uranate (18), nitrate and nitrite (19-22), selenate (23), chromate (24, 25) and halogenated hydrocarbons (13, 26-29). However, even though degradation.... Nitrate (NO3-) is sequentially reduced to nitrite (NO2-), nitric oxide (NO), nitrous oxide (N2O) and nitrogen gas (N2) as shown by equation 2-6 (58). 22 This process has been observed to occur naturally in suboxic conditions such as can occur...

  6. Survey of subsurface treatment technologies for environmental restoration sites at Sandia National Laboratories, New Mexico.

    SciTech Connect

    McGrath, Lucas K.; Ho, Clifford Kuofei; Wright, Jerome L.

    2003-08-01

    This report provides a survey of remediation and treatment technologies for contaminants of concern at environmental restoration (ER) sites at Sandia National Laboratories, New Mexico. The sites that were evaluated include the Tijeras Arroyo Groundwater, Technical Area V, and Canyons sites. The primary contaminants of concern at these sites include trichloroethylene (TCE), tetrachloroethylene (PCE), and nitrate in groundwater. Due to the low contaminant concentrations (close to regulatory limits) and significant depths to groundwater ({approx}500 feet) at these sites, few in-situ remediation technologies are applicable. The most applicable treatment technologies include monitored natural attenuation and enhanced bioremediation/denitrification to reduce the concentrations of TCE, PCE, and nitrate in the groundwater. Stripping technologies to remove chlorinated solvents and other volatile organic compounds from the vadose zone can also be implemented, if needed.

  7. Microbial based chlorinated ethene destruction

    DOEpatents

    Bagwell, Christopher E. (Aiken, SC); Freedman, David L. (Clemson, SC); Brigmon, Robin L. (North Augusta, SC); Bratt, William B. (Atlanta, GA); Wood, Elizabeth A. (Marietta, GA)

    2009-11-10

    A mixed culture of Dehalococcoides species is provided that has an ability to catalyze the complete dechlorination of polychlorinated ethenes such as PCE, TCE, cDCE, 1,1-DCE and vinyl chloride as well as halogenated ethanes such as 1,2-DCA and EDB. The mixed culture demonstrates the ability to achieve dechlorination even in the presence of high source concentrations of chlorinated ethenes.

  8. Phytoscreening for chlorinated solvents using rapid in vitro SPME sampling: Application to urban plume in Verl, Germany

    USGS Publications Warehouse

    Limmer, M.A.; Balouet, J.-C.; Karg, F.; Vroblesky, D.A.; Burken, J.G.

    2011-01-01

    Rapid detection and delineation of contaminants in urban settings is critically important in protecting human health. Cores from trees growing above a plume of contaminated groundwater in Verl, Germany, were collected in 1 day, with subsequent analysis and plume mapping completed over several days. Solid-phase microextraction (SPME) analysis was applied to detect tetrachloroethene (PCE) and trichloroethene (TCE) to below nanogram/liter levels in the transpiration stream of the trees. The tree core concentrations showed a clear areal correlation to the distribution of PCE and TCE in the groundwater. Concentrations in tree cores were lower than the underlying groundwater, as anticipated; however, the tree core water retained the PCE:TCE signature of the underlying groundwater in the urban, populated area. The PCE:TCE ratio can indicate areas of differing degradation activity. Therefore, the phytoscreening analysis was capable not only of mapping the spatial distribution of groundwater contamination but also of delineating zones of potentially differing contaminant sources and degradation. The simplicity of tree coring and the ability to collect a large number of samples in a day with minimal disruption or property damage in the urban setting demonstrates that phytoscreening can be a powerful tool for gaining reconnaissance-level information on groundwater contaminated by chlorinated solvents. The use of SPME decreases the detection level considerably and increases the sensitivity of phytoscreening as an assessment, monitoring, and phytoforensic tool. With rapid, inexpensive, and noninvasive methods of detecting and delineating contaminants underlying homes, as in this case, human health can be better protected through screening of broader areas and with far faster response times. ?? 2011 American Chemical Society.

  9. Geohydrology and distribution of volatile organic compounds in ground water in the Casey Village area, Bucks County, Pennsylvania

    USGS Publications Warehouse

    Sloto, Ronald A.; Conger, Randall W.; Grazul, Kevin E.

    1998-01-01

    Casey Village and the adjoining part of the U.S. Naval Air Warfare Center (NAWC) are underlain by the Late Triassic-age Stockton Formation, which consists of a dipping series of siltstones and sandstones. The direction of vertical ground-water gradients in the Stockton Formation varies among well locations and sometimes with time. Vertical gradients can be substantial; the difference in water levels at one well pair (two wells screened at different depths) was 7.1 ft (feet) over a 32-ft vertical section of the aquifer. Potentiometric-surface maps show a groundwater divide that bisects the Casey Village area. For wells screened between 18 and 64 ft below land surface (bls), the general ground-water gradient is to the east and northeast on the east side of the divide and to the south and southwest on the west side of the divide. For wells screened between 48 and 106 ft bls, the general ground-water gradient is to the northeast on the east side of the divide and to the southwest and northwest on the west side of the divide. An aquifer test at one well in Casey Village caused drawdown in wells on the opposite side of the ground-water divide on the NAWC and shifted the ground-water divide in the deeper potentiometric surface to the west. Drawdowns formed an elliptical pattern, which indicates anisotropy; however, anisotropy is not aligned with strike or dip. Hydraulic stress caused by pumping crosses stratigraphic boundaries. Between 1993 and 1996, the trichloroethylene (TCE) concentration in water samples collected from wells in Casey Village decreased. The highest concentration of TCE measured in water from one well decreased from 1,200 mg/L (micrograms per liter) in 1993 when domestic wells were pumped in Casey Village to 140 mg/L in 1996, 3 years after the installation of public water and the cessation of domestic pumping. This suggests that pumping of domestic wells may have contributed to TCE migration. Between 1993 and 1996, the tetrachloroethylene (PCE) concentration in water samples collected from wells in Casey Village decreased only slightly. The highest concentration of PCE measured in water from one well decreased from 720 mg/L in 1993 to 630 mg/L in 1996. The distribution of TCE and PCE in ground water indicates the presence of separate PCE and TCE plumes, each with a different source area. The TCE plume appears to be moving in two directions away from the ground-water divide area. The pumping of a domestic well may have caused TCE migration into the ground-water divide area. From the divide area, the TCE plume appears to be moving both to the east and the west under the natural hydraulic gradient. Aquifer-isolation tests conducted in the well with the highest TCE concentrations showed that concentrations of TCE in water samples from the isolated intervals were similar but slightly lower in the deeper isolated zones than in the shallower isolated zones. Upward flow was measured in this well during geophysical logging. If the source of TCE to the well was from shallow fractures, upward flow of less contaminated water could be flushing TCE from the immediate vicinity of this well. This may help explain why the concentration of TCE in water from this well decreased an order of magnitude between 1993 and 1996.

  10. Uptake and fate of organohalogens from contaminated groundwater in woody plants

    SciTech Connect

    Sytsma, L.; Mulder, J.; Schneider, J.

    1997-12-31

    The emerging technology of phytoremediation uses green plants for low-cost, low-tech remediation processes in which selected plants and natural or engineered microorganisms work together to metabolize, convert, absorb, accumulate, sequester, or otherwise render harmless multiple environmental contaminants. For many organic contaminants, such as tricholoroethylene (TCE) and tetrachloroethylene (PCE), there is evidence that plants can degrade a portion of the organohalogen that is taken up to form less volatile compounds, such as trichloroacetic acid (TCAA), which are sequestered in the plant tissue while the remainder is passed out of the leaf tissue with the transpiration stream. Analysis of leaves from trees in uncontaminated areas gives TCAA concentrations that are typically under 100 ng/g TCAA, while in contaminated areas concentrations run as high as 1,000 ng/g. Hybrid poplar plants fed by TCE- and PCE-spiked nutrient solutions in a greenhouse showed elevated TCAA levels in the leaves within a week, as well as evidence for evapotranspiration of the TCE and PCE.

  11. 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

  12. Use of Mini-Sprinklers to Strip Trichloroethylene and Tetrachloroethylene from Contaminated Ground Water.

    SciTech Connect

    Brerisford, Yvette, C.; Bush, Parshall, B.; Blake, John, I.; Bayer, Cassandra L.

    2003-01-01

    Berisford, Y.C., P.B. Bush, J.I. Blake, and C.L. Bayer. 2003. Use of mini-sprinklers to strip trichloroethylene and tetrachloroethylene from contaminated ground water. J. Env. Qual. 32:801-815. Three low-volume mini-sprinklers were tested for their efficacy to strip trichloroethylene (TCE) and tetrachloroethylene (PCE) from water. Deionized water spiked with TCE and PCE was pumped through a mini-sprinkler supported on top of a 1.8-m-tall. Water was collected in collection vessels at 0.61 and 1.22 m above the ground on support columns that were spaced at 0.61-m intervals from the riser base, and samples were composited per height and distance from the riser. Overall, air-stripping reduced dissolved concentrations of TCE and PCE by 99.1 to 100 and 96.9 to 100%, respectively. Mini-sprinklers offer the advantages of (i) easy setup in series that can be used on practically any terrain; (ii) operation over a long period of time that does not threaten aquifer depletion; (iii) use in small or confined aquifers in which the capacity is too low to support large irrigation or pumping systems; and (iv) use in forests in which the small, low-impact droplets of the mini-sprinklers do not damage bark and in which trees can help manage (via evapotransporation) excess waste water.

  13. C, Cl and H compound-specific isotope analysis to assess natural versus Fe(0) barrier-induced degradation of chlorinated ethenes at a contaminated site.

    PubMed

    Audí-Miró, Carme; Cretnik, Stefan; Torrentó, Clara; Rosell, Mònica; Shouakar-Stash, Orfan; Otero, Neus; Palau, Jordi; Elsner, Martin; Soler, Albert

    2015-12-15

    Compound-specific isotopic analysis of multiple elements (C, Cl, H) was tested to better assess the effect of a zero-valent iron-permeable reactive barrier (ZVI-PRB) installation at a site contaminated with tetrachloroethene (PCE) and trichloroethene (TCE). The focus was on (1) using (13)C to evaluate natural chlorinated ethene biodegradation and the ZVI-PRB efficiency; (2) using dual element (13)C-(37)Cl isotopic analysis to distinguish biotic from abiotic degradation of cis-dichloroethene (cis-DCE); and (3) using (13)C-(37)Cl-(2)H isotopic analysis of cis-DCE and TCE to elucidate different contaminant sources. Both biodegradation and degradation by ZVI-PRB were indicated by the metabolites that were detected and the (13)C data, with a quantitative estimate of the ZVI-PRB efficiency of less than 10% for PCE. Dual element (13)C-(37)Cl isotopic plots confirmed that biodegradation was the main process at the site including the ZVI-PRB area. Based on the carbon isotope data, approximately 45% and 71% of PCE and TCE, respectively, were estimated to be removed by biodegradation. (2)H combined with (13)C and (37)Cl seems to have identified two discrete sources contributing to the contaminant plume, indicating the potential of ?(2)H to discriminate whether a compound is of industrial origin, or whether a compound is formed as a daughter product during degradation. PMID:26248540

  14. Reductive dechlorination of tri- and tetrachloroethylenes depends on transition from aerobic to anaerobic conditions

    SciTech Connect

    Kastner, M. )

    1991-07-01

    Aerobic enrichment cultures from contaminated groundwaters dechlorinated trichloroethylene (TCE) (14.6 mg/liter; 111 {mu}mol/liter) and tetrachloroethylene (PCE) (16.2 mg/liter; 98 {mu}mol/liter) reductively within 4 days after the transition from aerobic to anaerobic conditions. The transformation products were equimolar amounts of cis-1,2-dichloroethylene and traces of 1,1-dichloroethylene. No other chlorinated product and no methane were detected. The change was accompanied by the release of sulfide, which caused a decrease in the redox potential from 0 - {minus}150 mV. In sterile control experiments, sulfide led to the abiotic formation of traces of 1,1-dichloroethylene without cis-1,2-dichloroethylene production. The reductive dechlorination of PCE via TCE depended on these specific transition conditions after consumption of the electron acceptor oxygen or nitrate. Repeated feeding of TCE or PCE to cultures after the change to anaerobic conditions yielded no further dechlorination. Only aerobic subcultures with an air/liquid ratio of 1:4 maintained dechlorination activities; anaerobic subcultures showed no transformation. Bacteria from noncontaminated sites showed no reduction under the same conditions.

  15. Biotransformation of chlorinated aliphatic solvents in the presence of aromatic compounds under methanogenic conditions

    SciTech Connect

    Liang, L.N.; Grbic-Galic, D. . Dept. of Civil Engineering)

    1993-08-01

    Transformation of carbon tetrachloride (CT) and tetrachloroethylene (PCE) was studied under methanogenic conditions, in the presence or absence of toluene, ethylbenzene, phenol, and benzoate. Microbial inoculate for the experiments were derived from three groundwater aquifers contaminated by jet fuel or creosote. CT and PCE were reductively dechlorinated in all the examined castes (CT to chloroform [CF]; PCE to trichloroethylene [TCE], trans-1,2-dichloroethylene [DCE], and vinyl chloride [VC]). In the aquifer microcosms, the electron donors used for the reductive transformations were most likely the unidentified organic compounds present on aquifer solids, or storage materials in microorganisms. Alternatively, molecular hydrogen from the anaerobic incubator atmosphere could have been used. The addition of benzoate caused a decrease in rates of dechlorination if benzoate was transformed. Phenol and ethylbenzene were not degraded and did not influence the transformation of CT or PCE. Toluene, in most of the studied cases, had no influence on reductive dechlorination of either CT or PCE. Only in microcosms derived from a JP-4 jet fuel-contaminated aquifer did the anaerobic degradation of toluene occur simultaneously with reductive dechlorination of PCE, suggesting that toluene might possibly have been used as an electron donor for reductive transformation of chlorinated solvents.

  16. 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

  17. Insights into the use of time-lapse GPR data as observations for inverse multiphase flow simulations of DNAPL migration

    USGS Publications Warehouse

    Johnson, R.H.; Poeter, E.P.

    2007-01-01

    Perchloroethylene (PCE) saturations determined from GPR surveys were used as observations for inversion of multiphase flow simulations of a PCE injection experiment (Borden 9??m cell), allowing for the estimation of optimal bulk intrinsic permeability values. The resulting fit statistics and analysis of residuals (observed minus simulated PCE saturations) were used to improve the conceptual model. These improvements included adjustment of the elevation of a permeability contrast, use of the van Genuchten versus Brooks-Corey capillary pressure-saturation curve, and a weighting scheme to account for greater measurement error with larger saturation values. A limitation in determining PCE saturations through one-dimensional GPR modeling is non-uniqueness when multiple GPR parameters are unknown (i.e., permittivity, depth, and gain function). Site knowledge, fixing the gain function, and multiphase flow simulations assisted in evaluating non-unique conceptual models of PCE saturation, where depth and layering were reinterpreted to provide alternate conceptual models. Remaining bias in the residuals is attributed to the violation of assumptions in the one-dimensional GPR interpretation (which assumes flat, infinite, horizontal layering) resulting from multidimensional influences that were not included in the conceptual model. While the limitations and errors in using GPR data as observations for inverse multiphase flow simulations are frustrating and difficult to quantify, simulation results indicate that the error and bias in the PCE saturation values are small enough to still provide reasonable optimal permeability values. The effort to improve model fit and reduce residual bias decreases simulation error even for an inversion based on biased observations and provides insight into alternate GPR data interpretations. Thus, this effort is warranted and provides information on bias in the observation data when this bias is otherwise difficult to assess. ?? 2006 Elsevier B.V. All rights reserved.

  18. Risk-based economic decision analysis of remediation options at a PCE-contaminated site.

    PubMed

    Lemming, Gitte; Friis-Hansen, Peter; Bjerg, Poul L

    2010-05-01

    Remediation methods for contaminated sites cover a wide range of technical solutions with different remedial efficiencies and costs. Additionally, they may vary in their secondary impacts on the environment i.e. the potential impacts generated due to emissions and resource use caused by the remediation activities. More attention is increasingly being given to these secondary environmental impacts when evaluating remediation options. This paper presents a methodology for an integrated economic decision analysis which combines assessments of remediation costs, health risk costs and potential environmental costs. The health risks costs are associated with the residual contamination left at the site and its migration to groundwater used for drinking water. A probabilistic exposure model using first- and second-order reliability methods (FORM/SORM) is used to estimate the contaminant concentrations at a downstream groundwater well. Potential environmental impacts on the local, regional and global scales due to the site remediation activities are evaluated using life cycle assessments (LCA). The potential impacts on health and environment are converted to monetary units using a simplified cost model. A case study based upon the developed methodology is presented in which the following remediation scenarios are analyzed and compared: (a) no action, (b) excavation and off-site treatment of soil, (c) soil vapor extraction and (d) thermally enhanced soil vapor extraction by electrical heating of the soil. Ultimately, the developed methodology facilitates societal cost estimations of remediation scenarios which can be used for internal ranking of the analyzed options. Despite the inherent uncertainties of placing a value on health and environmental impacts, the presented methodology is believed to be valuable in supporting decisions on remedial interventions. PMID:20117877

  19. Introduction Competition for H2 in a PCE-contaminated aquifer

    E-print Network

    Lenstra, Arjen K.

    is a bacterial anaerobic respiration in which CEs are sequentially reduced to harmless ethene. The interestingA detected on the site In presence of Fe(III) organohalide respiring bacteria are outcompeted for H2 (fig.2. Chlorinated ethenes (CEs) belong to the most common groundwater contaminants. Organohalide respiration

  20. Effects of three concentrations of mixed fatty acids on dechlorination of tetrachloroethene in aquifer microcosms

    SciTech Connect

    Gibson, S.A.; Roberson, D.S. ); Russell, H.H. . Robert S. Kerr Environmental Research Lab.)

    1994-03-01

    Chloroethenes are among the most common organic contaminants of ground water. The biotransformation of these compounds by reductive dechlorination is a promising technology for in situ treatment. The effects of three concentrations of a fatty acids mixture on the reductive dehalogenation of tetrachloroethane (PCE) were studied in methanogenic microcosms. These microcosms were constructed with slurries of aquifer solids collected from an area impacted both by aviation gasoline and chlorinated ethanes at Traverse City, Michigan. The microcosms were amended with approximately 30 [mu]M PCE and one of three concentrations of a mixture of low-molecular-weight organic axis, or were part of a control set that received no amendment. The observed lag or adaptation times before the onset of PCE dehalogenation were 51 d, 65 d, 86 d, and > 233 d (no acids). After 233 d of incubation, no PCE was detectable in any of the fatty-acid-supplemented microcosms, but 23 to 27 [mu]M of combined tri- and dichloroethenes (TCEs, DCEs) was detected. PCE was not dechlorinated in microcosms without a fatty acid supplement. Although there were observed differences in the length of the lag time, the amount of ultimately dechlorinated PCE was similar. A zero-order rate constant of 0.3 [mu]M d[sup [minus]1] was calculated for PCE dechlorination and for TCE dechlorination for the two series of microcosms receiving 0.1 and 1.0 mM fatty acid supplements. Of the fatty acids tested in the mixture, butyrate oxidation appeared to be the most probable link to PCE dechlorination.

  1. Time-Dependent Interfacial Properties and DNAPL Mobility

    SciTech Connect

    Tuck, D.M.

    1999-03-10

    Interfacial properties play a major role in governing where and how dense nonaqueous phase liquids (DNAPLs) move in the subsurface. Interfacial tension and contact angle measurements were obtained for a simple, single component DNAPL (tetrachloroethene, PCE), complex laboratory DNAPLs (PCE plus Sudan IV dye), and a field DNAPL from the Savannah River Site (SRS) M-Area DNAPL (PCE, trichloroethene [TCE], and maching oils). Interfacial properties for complex DNAPLs were time-dependent, a phenomenon not observed for PCE alone. Drainage capillary pressure-saturation curves are strongly influenced by interfacial properties. Therefore time-dependence will alter the nature of DNAPL migration and penetration. Results indicate that the time-dependence of PCE with relatively high Sudan IV dye concentrations is comparable to that of the field DNAPL. Previous DNAPL mobility experiments in which the DNAPL was dyed should be reviewed to determine whether time-dependent properties influenced the resutls. Dyes appear to make DNAPL more complex, and therefore a more realistic analog for field DNAPLs than single component DNAPLs.

  2. Natural attenuation of chlorinated ethene compounds: model development and field-scale application at the Dover site

    SciTech Connect

    Clement, T P.; Johnson, Christian D.); Sun, Y; Klecka, Gary M.; Bartlett, Craig

    2000-03-31

    A multi-dimensional, multi-species reactive transport model was developed to aid in the analysis of natural attenuation design at chlorinated solvent sites. The model can simulate several simultaneously occurring attenuation processes including aerobic and anaerobic biological degradation processes. The developed model was applied to analyze field-scale transport and biodegradation processes occurring at the Area-6 site in Dover Air Force Base, Delaware. The model was calibrated to field data collected at this site. The calibrated model reproduced the general groundwater flow patterns, and also successfully recreated the observed distribution of PCE, TCE, DCE, VC and chloride plumes. Field-scale decay rates of these contaminant plumes were also estimated. The decay rates are within the range of values that were previously estimated based on lab-scale microcosm and field-scale transect analyses. Model simulation results indicated that the anaerobic degradation rate of TCE, source loading rate, and groundwater transport rate are the important model parameters. Sensitivity analysis of the model indicated that the shape and extent of the predicted TCE plume is most sensitive to transmissivity values. The total mass of the predicted TCE plume is most sensitive to TCE anaerobic degradation rates. The numerical model developed in this study is a useful engineering tool for integrating field-scale natural attenuation data within a rational modeling framework. The model results can be used for quantifying the relative importance of various simultaneously occurring natural attenuation processes.

  3. ASSESSING AEROBIC NATURAL ATTENUATION OF TRICHLOROETHENE AT FOUR DOE SITES

    SciTech Connect

    Michael C. Koelsch; Robert C. Starr; Kent S. Sorenson, Jr.

    2005-03-01

    A 3-year Department of Energy Environmental Science Management Program (EMSP) project is currently investigating natural attenuation of trichloroethane (TCE) in aerobic groundwater. This presentation summarizes the results of a screening process to identify TCE plumes at DOE facilities that are suitable for assessing the rate of TCE cometabolism under aerobic conditions. In order to estimate aerobic degradation rates, plumes had to meet the following criteria: TCE must be present in aerobic groundwater, a conservative co-contaminant must be present and have approximately the same source as TCE, and the groundwater velocity must be known. A total of 127 TCE plumes were considered across 24 DOE sites. The four sites retained for the assessment were: (1) Brookhaven National Laboratory, OU III; (2) Paducah Gaseous Diffusion Plant, Northwest Plume; (3) Rocky Flats Environmental Technology Site, Industrialized Area--Southwest Plume and 903 Pad South Plume; and (4) Savannah River Site, A/M Area Plume. For each of these sites, a co-contaminant derived from the same source area as TCE was used as a nonbiodegrading tracer. The tracer determined the extent to which concentration decreases in the plume can be accounted for solely by abiotic processes such as dispersion and dilution. Any concentration decreases not accounted for by these processes must be explained by some other natural attenuation mechanism. Thus, ''half-lives'' presented herein are in addition to attenuation that occurs due to hydrologic mechanisms. This ''tracer-corrected method'' has previously been used at the DOE's Idaho National Engineering and Environmental Laboratory in conjunction with other techniques to document the occurrence of intrinsic aerobic cometabolism. Application of this method to other DOE sites is the first step to determining whether this might be a significant natural attenuation mechanism on a broader scale. Application of the tracer-corrected method to data from the Brookhaven National Laboratory site using carbon tetrachloride as the conservative tracer under aerobic conditions showed evidence of TCE attenuation with a range of TCE half-lives from 2 to 9.5 years. At Paducah Gaseous Diffusion Plant's Northwest Plume the assessment was performed using Tc-99 as the conservative tracer. TCE appears to have a half-life of about 7 years in the lower portion of the Northwest Plume regional gravel aquifer. Evidence for TCE attenuation at Rocky Flats Environmental Technology Site was identified in two plumes. PCE was used as the conservative tracer in both plumes. TCE appears to be attenuating with a half-life of 0.85 years in the Industrialized Area--Southwest Plume, and with a half-life of 2.4 years in the 903 Pad South Plume. At the Savannah River Site, A/M Area, PCE was used as the conservative tracer in five different horizons. In four of the five horizons, TCE appears to be degrading with a half-life between 4 and 12 years, while no degradation could be quantified in the fifth horizon. If aerobic TCE degradation can be confirmed at these sites, this attenuation mechanism might be important much more often than previously thought, and might make MNA feasible where it was previously not considered.

  4. Probabilistic Health Risk Assessment of Chemical Mixtures: Importance of Travel Times and Connectivity

    NASA Astrophysics Data System (ADS)

    Henri, Christopher V.; Fernàndez-Garcia, Daniel; de Barros, Felipe P. J.

    2014-05-01

    Subsurface contamination cases giving rise to groundwater pollutions are extensively found in all industrialized countries. Under this pressure, risk assessment methods play an important role in population protection by (1) quantifying the potential impact on human health of an aquifer contamination and (2) helping and driving decisions of groundwater-resource managers. Many reactive components such as chlorinated solvents or nitrates potentially experience attenuation processes under common geochemical conditions. This represents an attractive and extensively used remediation solution but leads often to the production of by-products before to reach a harmless chemical form. This renders mixtures of contaminants a common issue for groundwater resources managers. In this case, the threat posed by these contaminants to human health at a given sensitive location greatly depends on the competition between reactive and advective-dispersive characteristic times. However, hydraulic properties of the aquifer are known to be spatially variable, which can lead to the formation of preferential flow channels and fast contamination pathways. Therefore, the uncertainty on the spatial distribution of the aquifer properties controlling the plume travel time may then play a particular role in the human health risk assessment of chemical mixtures. We investigate here the risk related to a multispecies system in response to different degrees of heterogeneity of the hydraulic conductivity (K or Y =ln(K)). This work focuses on a Perchloroethylene (PCE) contamination problem followed by the sequential first-order production/biodegradation of its daughter species Trichloroethylene (TCE), Dichloroethylene (DCE) and Vinyl Chlorine (VC). For this specific case, VC is known to be a highly toxic contaminant. By performing numerical experiments, we evaluate transport through three-dimensional mildly (?Y 2=1.0) and highly (?Y 2=4.0) heterogeneous aquifers. Uncertainty on the hydraulic conductivity field is considered through a Monte Carlo scheme, and statistics of the total risk for human health (RT) related to the mixtures of the four carcinogenic plumes are evaluated. Results show two distinct spatiotemporal behavior of the RT estimation. Simulations in highly heterogeneous aquifers display a lower mean of RT close to the injection and higher further away. We explain this by the distinct ranges of travel times and connectivity metrics related to the two sets of aquifers. A high ?Y 2 trends to decrease the travel time (and increase the connectivity). Early travel times, associated to channeling effects, are intuitively perceived as an indicator for high risk. However, in our case, early travel times lead a limited production of highly toxic daughter species and a lower total risk. Our results reflect then the interplay between the characteristic reactive time for each component and the characteristic travel time of the plume since the production of VC depends on these factors.

  5. Radon as a Natural Partitioning Tracer for Locating and Quantifying DNAPL Saturation in the Subsurface

    NASA Astrophysics Data System (ADS)

    Davis, B. M.; Istok, J.; Semprini, L.

    2002-12-01

    The inability to locate and quantify dense nonaqueous phase liquid (DNAPL) saturation in the subsurface presents obstacles to site characterization and remediation. The objective of this study is to evaluate the use of naturally occurring radon as an in-situ, partitioning tracer to locate and quantify DNAPL saturation. In the saturated zone, radon emanating from aquifer solids occurs as a dissolved gas and, due to its non-polarity, partitions into DNAPL. Partitioning between the DNAPL and aqueous phases results in retarded radon transport during groundwater flow. The radon retardation factor can be determined using single-well 'push-pull' tracer tests, enabling the calculation of the DNAPL saturation. Radon can also be used as a 'static' partitioning tracer, whereby grab samples of radon from monitoring wells in contaminated and non-contaminated portions of an aquifer are collected and compared to calculate the DNAPL saturation and to monitor saturation changes as remediation proceeds. The utility of these methods was investigated in the laboratory using a physical aquifer model (PAM). Static and push-pull tests were performed before and after contamination of a portion of the PAM sediment pack with trichloroethene (TCE). The PAM was then remediated using alcohol cosolvent and tap water flushes, and static and push-pull tests were performed to assess the efficacy of remediation. Numerical simulations were used to estimate the retardation factor for radon in the push-pull tests. Radon partitioning was observed in static and push-pull tests conducted after TCE contamination. Calculated TCE saturations ranged up to 1.4 % (static test) and 14.1 % (push-pull test), based on the numerical method modeling approach used to analyze the results. Post-remediation tests showed decreases in TCE saturations. The results show that radon is sensitive to changes in DNAPL (e.g., TCE) saturation in space and time. Recent advances in numerical modeling of radon in push-pull tests have shown the influence of TCE saturation distribution and initial radon concentrations on radon breakthrough curves and calculated TCE saturations. These advances have led to more accurate predictions of the TCE saturation in the PAM. The push-pull method was applied at a field site at Dover Air Force Base, Delaware. The site consists of an aquifer 'test cell' 27 ft long and 18 ft wide surrounded by steel pilings to a clay confining unit 40 ft below grade. Push-pull tests were performed before and after contamination of the test cell with perchloroethene (PCE). Push-pull tests performed before contamination showed no evidence of radon retardation, while tests performed after contamination showed evidence of retardation and suggested the presence of PCE.

  6. Assessment of subsurface chlorinated solvent contamination using tree cores at the front street site and a former dry cleaning facility at the Riverfront Superfund site, New Haven, Missouri, 1999-2003

    USGS Publications Warehouse

    Schumacher, John G.; Struckhoff, Garrett C.; Burken, Joel G.

    2004-01-01

    Tree-core sampling has been a reliable and inexpensive tool to quickly assess the presence of shallow (less than about 30 feet deep) tetrachloroethene (PCE) and trichloroethene (TCE) contamination in soils and ground water at the Riverfront Superfund Site. This report presents the results of tree-core sampling that was successfully used to determine the presence and extent of chlorinated solvent contamination at two sites, the Front Street site (operable unit OU1) and the former dry cleaning facility, that are part of the overall Riverfront Superfund Site. Traditional soil and ground-water sampling at these two sites later confirmed the results from the tree-core sampling. Results obtained from the tree-core sampling were used to design and focus subsequent soil and ground-water investigations, resulting in substantial savings in time and site assessment costs. The Front Street site is a small (less than 1-acre) site located on the Missouri River alluvium in downtown New Haven, Missouri, about 500 feet from the south bank of the Missouri River. Tree-core sampling detected the presence of subsurface PCE contamination at the Front Street site and beneath residential property downgradient from the site. Core samples from trees at the site contained PCE concentrations as large as 3,850 mg-h/kg (micrograms in headspace per kilogram of wet core) and TCE concentrations as large as 249 mg-h/kg. Soils at the Front Street site contained PCE concentrations as large as 6,200,000 mg/kg (micrograms per kilogram) and ground-water samples contained PCE concentrations as large as 11,000 mg/L (micrograms per liter). The former dry cleaning facility is located at the base of the upland that forms the south bank of the Missouri River alluvial valley. Tree-core sampling did not indicate the presence of PCE or TCE contamination at the former dry cleaning facility, a finding that was later confirmed by the analyses of soil samples collected from the site. The lateral extent of PCE contamination in trees was in close agreement with the extent of subsurface PCE contamination determined using traditional soil and ground-water sampling methods. Trees growing in soils containing PCE concentrations of 60 to 5,700 mg/kg or larger or overlying ground water containing PCE concentrations from 5 to 11,000 mg/L generally contained detectable concentrations of PCE. The depth to contaminated ground water was about 20 to 25 feet below the land surface. Significant quantitative relations [probability (p) values of less than 0.05 and correlation coefficient (r2) values of 0.88 to 0.90] were found between PCE concentrations in trees and subsurface soils between 4 and 16 feet deep. The relation between PCE concentrations in trees and underlying ground water was less apparent (r2 value of 0.17) and the poor relation is thought to be the result of equilibrium with PCE concentrations in soil and vapor in the unsaturated zone. Based on PCE concentrations detected in trees at the Front Street site and trees growing along contaminated tributaries in other operable units, and from field hydroponic experiments using hybrid poplar cuttings, analysis of tree-core samples appears to be able to detect subsurface PCE contamination in soils at levels of several hundred micrograms per liter or less and PCE concentrations in the range of 8 to 30 mg/L in ground water in direct contact with the roots. Loss of PCE from tree trunks by diffusion resulted in an exponential decrease in PCE concentrations with increasing height above the land surface in most trees. The rate of loss also appeared to be a function of the size and growth characteristics of the tree as some trees exhibited a linear loss with increasing height. Diffusional loss of PCE in small (0.5-inch diameter) trees was observed to occur at a rate more than 10 times larger than in trees 6.5 inches in diameter. Concentrations of PCE also exhibited directional variability around the tree trunks and concentration differe

  7. Probabilistic approach to estimating indoor air concentrations of chlorinated volatile organic compounds from contaminated groundwater: a case study in San Antonio, Texas.

    PubMed

    Johnston, Jill E; Gibson, Jacqueline MacDonald

    2011-02-01

    This paper describes a probabilistic model, based on the Johnson-Ettinger algorithm, developed to characterize the current and historic exposure to tricholorethylene (TCE) and tetrachlorethylene (PCE) in indoor air from plumes of groundwater contamination emanating from the former Kelly Air Force Base in San Antonio, Texas. We estimate indoor air concentration, house by house, in 30?101 homes and compare the estimated concentrations with measured values in a small subset of homes. We also compare two versions of the Johnson-Ettinger model: one used by the Environmental Protection Agency (EPA) and another based on an alternative parametrization. The modeled mean predicted PCE concentration historically exceeded PCE screening levels (0.41 ug/m(3)) in 5.5% of houses, and the 95th percentile of the predicted concentration exceeded screening levels in 85.3% of houses. For TCE, the mean concentration exceeded the screening level (0.25 ug/m(3)) in 49% of homes, and the 95th percentile of the predicted concentration exceeded the screening level in 99% of homes. The EPA model predicts slightly lower indoor concentrations than the alternative parametrization. Comparison with measured samples suggests both models, with the inputs selected, underestimate indoor concentrations and that the 95th percentiles of the predicted concentrations are closer to measured concentrations than predicted mean values. PMID:21162557

  8. Process for removing halogenated aliphatic and aromatic compounds from petroleum products. [Polychlorinated biphenyls; methylene chloride; perchloroethylene; trichlorofluoroethane; trichloroethylene; chlorobenzene

    DOEpatents

    Googin, J.M.; Napier, J.M.; Travaglini, M.A.

    1982-03-31

    A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contracting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible polyhydroxy compound, such as, water, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds in the low polar or nonpolar solvent by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered for recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 2 tables.

  9. 78 FR 15721 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-12

    ...Request; NESHAP for Perchloroethylene Dry Cleaning Facilities (Renewal) AGENCY: Environmental...Title: NESHAP for Perchloroethylene Dry Cleaning Facilities (Renewal). ICR Numbers...or operators of perchloroethylene dry cleaning facilities. Estimated Number of...

  10. Consistency of the interfacial tracer technique: experimental evaluation

    NASA Astrophysics Data System (ADS)

    Kim, Heonki; Rao, P. Suresh C.; Annable, Michael D.

    1999-11-01

    Miscible displacement experiments were conducted using sodium dodecylbenzenesulfonate (SDBS) and cetylpyridinium chloride (CPC) as interfacial tracers to measure non-aqueous phase liquid (NAPL)-water interfacial areas ( anw) in columns packed with silanized glass beads which were coated with either n-decane or perchloroethylene (PCE). The consistency of the interfacial tracer technique was evaluated by showing that: (1) anw values measured with two tracers for two NAPLs were similar; (2) the interfacial adsorption isotherm estimated from the surfactant retardation factors was comparable to that predicted from interfacial tension data and the Gibbs adsorption equation; and (3) the measured anw values were comparable with those estimated from a simple geometrical analysis of the solid surface area of the glass beads of known size and shape.

  11. Pre-oxidation efficiency of BAC treatment for VOC removal

    SciTech Connect

    Yu, M.J.; Ahn, S.K.; Kim, Y.R.; Lee, S.H.

    1996-12-31

    Studies have been conducted to evaluate pretreatment for the removal of trichloroethylene(TCE), tetrachloroethylene(PCE) and 1,1,1-trichloroethane(1,1,1-TCA) using the combination of chemical oxidation and biological system with a selected microbial consortium (SMC). SMC were acclimated with the mixture of three chemicals as the sole carbon and energy source. The microbial species isolated from the soil contaminated by VOCs were gram-negative, rod-shaped bacteria, identified as Pseudomonas aeruginosa and Acinobacter calcoaceticus. The purposes of this research were to investigate pre-treatment efficiency for the removal of VOCs in groundwater and to develop design and operational parameters by using a pilot plant system. Simulated groundwater contaminated by VOCs was used to examine the efficiency of chemical oxidation using O{sub 3} alone, H{sub 2}O{sub 2}/O{sub 3}, following BAC column. The results showed the efficiency of pretreatment to remove VOCs through six processes composed of ozone generator, H{sub 2}O{sub 2}/O{sub 3} reactor and BAC column. Ozone and hydrogen peroxide pretreatment system was more effective to remove VOCs than non-pretreated system and subsequent biodegradation was influenced by pretreatment processes. The mixture of VOCs were removed in the order of TCE, PCE and TCA with H{sub 2}O{sub 2}/O{sub 3} and ozone alone. Results obtained show that chemically oxidized VOC can considerably decrease the adsorption capacity. Biological removal efficiency was in the order of TCE, TCA and PCE.

  12. Permanganate Treatment of DNAPLs in Reactive Barriers and Source Zone Flooding Schemes - Final Report

    SciTech Connect

    Schwartz, F.W.

    2000-10-01

    This study provides a detailed process-level understanding of the oxidative destruction of the organic contaminant emphasizing on reaction pathways and kinetics. A remarkable rise in the MnO{sup {minus}} consumption rate with TCA and PCE mixtures proves that the phase transfer catalysts have the ability to increase oxidation rate of DNAPLs either in pure phase or mixtures and that there is significant potential for testing the catalyzed scheme under field conditions. Secondly, as an attempt to enhance the oxidation of DNAPL, we are trying to exploit cosolvency effects, utilizing various alcohol-water mixtures to increase DNAPL solubilization. Preliminary results of cosolvency experiments indicate the enhancement in the transfer of nonaqueous phase TCE to TBA-water solution and the rate of TCE degradation in aqueous phase.

  13. Refinement of the density-modified displacement method for efficient treatment of tetrachloroethene source zones

    NASA Astrophysics Data System (ADS)

    Ramsburg, C. Andrew; Pennell, Kurt D.; Kibbey, Tohren C. G.; Hayes, Kim F.

    2004-10-01

    A novel method to remediate dense nonaqueous phase liquid (DNAPL) source zones that incorporates in situ density conversion of DNAPL via alcohol partitioning followed by displacement with a low interfacial tension (IFT) surfactant flood has been developed. Previous studies demonstrated the ability of the density-modified displacement (DMD) method to recover chlorobenzene (CB) and trichloroethene (TCE) from heterogeneous porous media without downward migration of the dissolved plume or free product. However, the extent of alcohol (n-butanol) partitioning required for in situ density conversion of high-density NAPLs, such as tetrachloroethene (PCE), could limit the utility of the DMD method. Hence, the objective of this study was to compare the efficacy of two n-butanol delivery approaches: an aqueous solution of 6% (wt) n-butanol and a surfactant-stabilized macroemulsion containing 15% (vol) n-butanol in water, to achieve density reduction of PCE-NAPL in two-dimensional (2-D) aquifer cells. Results of liquid-liquid equilibrium studies indicated that density conversion of PCE relative to water occurred at an n-butanol mole fraction of 0.56, equivalent to approximately 5 ml n-butanol per 1 ml of PCE when in equilibrium with an aqueous solution. In 2-D aquifer cell studies, density conversion of PCE was realized using both n-butanol preflood solutions, with effluent NAPL samples exhibiting density reductions ranging from 0.51 to 0.70 g/ml. Although the overall PCE mass recoveries were similar (91% and 93%) regardless of the n-butanol delivery method, the surfactant-stabilized macroemulsion preflood removed approximately 50% of the PCE mass. In addition, only 1.2 pore volumes of the macroemulsion solution were required to achieve in situ density conversion of PCE, compared to 6.4 pore volumes of the 6% (wt) n-butanol solution. These findings demonstrate that use of the DMD method with a surfactant-stabilized macroemulsion containing n-butanol holds promise as an effective source zone remediation technology, allowing for efficient recovery of PCE-DNAPL while mitigating downward migration of the dissolved plume and free product.

  14. Refinement of the density-modified displacement method for efficient treatment of tetrachloroethene source zones.

    PubMed

    Ramsburg, C Andrew; Pennell, Kurt D; Kibbey, Tohren C G; Hayes, Kim F

    2004-10-01

    A novel method to remediate dense nonaqueous phase liquid (DNAPL) source zones that incorporates in situ density conversion of DNAPL via alcohol partitioning followed by displacement with a low interfacial tension (IFT) surfactant flood has been developed. Previous studies demonstrated the ability of the density-modified displacement (DMD) method to recover chlorobenzene (CB) and trichloroethene (TCE) from heterogeneous porous media without downward migration of the dissolved plume or free product. However, the extent of alcohol (n-butanol) partitioning required for in situ density conversion of high-density NAPLs, such as tetrachloroethene (PCE), could limit the utility of the DMD method. Hence, the objective of this study was to compare the efficacy of two n-butanol delivery approaches: an aqueous solution of 6% (wt) n-butanol and a surfactant-stabilized macroemulsion containing 15% (vol) n-butanol in water, to achieve density reduction of PCE-NAPL in two-dimensional (2-D) aquifer cells. Results of liquid-liquid equilibrium studies indicated that density conversion of PCE relative to water occurred at an n-butanol mole fraction of 0.56, equivalent to approximately 5 ml n-butanol per 1 ml of PCE when in equilibrium with an aqueous solution. In 2-D aquifer cell studies, density conversion of PCE was realized using both n-butanol preflood solutions, with effluent NAPL samples exhibiting density reductions ranging from 0.51 to 0.70 g/ml. Although the overall PCE mass recoveries were similar (91% and 93%) regardless of the n-butanol delivery method, the surfactant-stabilized macroemulsion preflood removed approximately 50% of the PCE mass. In addition, only 1.2 pore volumes of the macroemulsion solution were required to achieve in situ density conversion of PCE, compared to 6.4 pore volumes of the 6% (wt) n-butanol solution. These findings demonstrate that use of the DMD method with a surfactant-stabilized macroemulsion containing n-butanol holds promise as an effective source zone remediation technology, allowing for efficient recovery of PCE-DNAPL while mitigating downward migration of the dissolved plume and free product. PMID:15358489

  15. Effect of vegetation in pilot-scale horizontal subsurface flow constructed wetlands treating sulphate rich groundwater contaminated with a low and high chlorinated hydrocarbon.

    PubMed

    Chen, Zhongbing; Wu, Shubiao; Braeckevelt, Mareike; Paschke, Heidrun; Kästner, Matthias; Köser, Heinz; Kuschk, Peter

    2012-10-01

    In order to characterize the effect of vegetation on performance of constructed wetlands (CWs) treating low and high chlorinated hydrocarbon, two pilot-scale horizontal subsurface flow (HSSF) CWs (planted with Phragmites australis and unplanted) treating sulphate rich groundwater contaminated with MCB (monochlorobenzene, as a low chlorinated hydrocarbon), (about 10 mg L(-1)), and PCE (perchloroethylene, as a high chlorinated hydrocarbon), (about 2 mg L(-1)), were examined. With mean MCB inflow load of 299 mg m(-2) d(-1), the removal rate was 58 and 208 mg m(-2) d(-1) in the unplanted and planted wetland, respectively, after 4 m from the inlet. PCE was almost completely removed in both wetlands with mean inflow load of 49 mg m(-2) d(-1). However, toxic metabolites cis-1,2-DCE (dichloroethene) and VC (vinyl chloride) accumulated in the unplanted wetland; up to 70% and 25% of PCE was dechlorinated to cis-1,2-DCE and VC after 4 m from the inlet, respectively. Because of high sulphate concentration (around 850 mg L(-1)) in the groundwater, the plant derived organic carbon caused sulphide formation (up to 15 mg L(-1)) in the planted wetland, which impaired the MCB removal but not statistically significant. The results showed significant enhancement of vegetation on the removal of the low chlorinated hydrocarbon MCB, which is probably due to the fact that aerobic MCB degraders are benefited from the oxygen released by plant roots. Vegetation also stimulated completely dechlorination of PCE due to plant derived organic carbon, which is potentially to provide electron donor for dechlorination process. The plant derived organic carbon also stimulated dissimilatory sulphate reduction, which subsequently have negative effect on MCB removal. PMID:22832338

  16. Test plan for in situ bioremediation demonstration of the Savannah River Integrated Demonstration Project DOE/OTD TTP No.: SR 0566-01. Revision 3

    SciTech Connect

    Hazen, T.C.

    1991-09-18

    This project is designed to demonstrate in situ bioremediation of groundwater and sediment contaminated with chlorinated solvents. Indigenous microorganisms will be simulated to degrade trichloroethylene (TCE), tetrachloroethylene (PCE) and their daughter products in situ by addition of nutrients to the contaminated zone. in situ biodegradation is a highly attractive technology for remediation because contaminants are destroyed, not simply moved to another location or immobilized, thus decreasing costs, risks, and time, while increasing efficiency and public and regulatory acceptability. Bioremediation has been found to be among the least costly technologies in applications where it will work.

  17. Nonpoint sources of volatile organic compounds in urban areas - Relative importance of land surfaces and air

    USGS Publications Warehouse

    Lopes, T.J.; Bender, D.A.

    1998-01-01

    Volatile organic compounds (VOCs) commonly detected in urban waters across the United States include gasoline-related compounds (e.g. toluene, xylene) and chlorinated compounds (e.g. chloroform, tetrachloroethane [PCE], trichloroethene [TCE]). Statistical analysis of observational data and results of modeling the partitioning of VOCs between air and water suggest that urban land surfaces are the primary nonpoint source of most VOCs. Urban air is a secondary nonpoint source, but could be an important source of the gasoline oxygenate methyl-tert butyl ether (MTBE). Surface waters in urban areas would most effectively be protected by controlling land-surface sources.

  18. Electron donor availability for microbial reductive processes following thermal treatment.

    PubMed

    Fletcher, Kelly E; Costanza, Jed; Pennell, Kurt D; Löffler, Frank E

    2011-12-15

    Thermal treatment is capable of removing significant free-phase chlorinated solvent mass while potentially enhancing bioremediation effectiveness by establishing temperature gradients in the perimeter of the source zone and by increasing electron donor availability. The objectives of this study were to determine the potential for enhanced reductive dechlorination activity at the intermediate temperatures that establish in the perimeter of the heated source zone, and to evaluate the effect of electron donor competition on the performance of the microbial reductive dechlorination process. Microcosms, constructed with tetrachloroethene- (PCE-) and trichloroethene- (TCE-) impacted soils from the Great Lakes, IL, and Ft. Lewis, WA, sites were incubated at temperatures of 24, 35, 50, 70, and 95 °C for 4 months. Reductive dechlorination did not occur in microcosms incubated at temperatures above 24 °C even though mesophilic PCE-to-cis-1,2-dichloroethene dechlorinators were present in Ft. Lewis soil suggesting electron donor limitations. Five days after cooling the microcosms to 24 °C and bioaugmentation with the methanogenic, PCE-to-ethene-dechlorinating consortium OW, at least 85% of the initial PCE and TCE were dechlorinated, but dechlorination ceased prior to complete conversion to ethene. Subsequent biostimulation with hydrogen gas mitigated the dechlorination stall, and conversion to ethene resumed. The results of this study demonstrated that temperatures >35 °C inhibit reductive dechlorination activity at the Great Lakes and Ft. Lewis sites, and that the majority of reducing equivalents released from the soil matrix during heat treatment are consumed in methanogenesis rather than reductive dechlorination. These observations suggest that bioaugmenting thermal treatment sites with cultures that do not contain methanogens may allow practitioners to realize enhanced dechlorination activity, a potential benefit of coupling thermal treatment with bioremediation. PMID:22048015

  19. Are reactive transport models reliable tools for reconstructing historical contamination scenarios?

    NASA Astrophysics Data System (ADS)

    Clement, P.

    2009-12-01

    This presentation will be based on a recent project effort that I completed while serving as a member of National Academy of Sciences and Engineering panel. The primary goal of this congressionally-mandated project effort was to review scientific evidence on the association between adverse health effect s and exposure to a contaminated water supply system at the U.S. Marine Corps Base Camp Lejeune (CLJ) in North Carolina. The detailed NRC study report was released in June 2009, and is available at this NRC weblink: http://www.nap.edu/catalog.php?record_id=12618. Multiple water supply systems at this Marine Base were contaminated with harmful chemicals, such as PCE, TCE and other waste products, since the early 50s. In 1982, a routine water quality survey completed at the site indicated the presence of several volatile organic compounds including PCE and TCE. Further investigations revealed that there are several waste disposal facilities located on-site that have discharged TCE and other waste products into groundwater systems. In addition, there was also an off-site dry cleaning facility located close to the Tarawa Terrace in-take well locations that disposed PCE into the subsurface environment. The dry cleaner has been using PCE since 1953 and disposed various forms of PCE-contaminated wastes in a septic tank and in several shallow pits. Therefore, the residents who lived in Tarawa Terrace on-site family housing units had the potential to be exposed to these harmful environmental contaminants through the drinking water source. In late 1980s, the concerns raised by CLJ public lead to an epidemiological study to evaluate the potential associations of utero and infant exposures to the VOCs and childhood cancers and birth defects. The study included births occurring during the period of 1968-1985 to women who were pregnant while they resided at the base. Since there was no monitoring data available for the study period (1968-1982), researchers used reactive transport models to reconstruct the historical concentration levels. In this presentation, I will first briefly review the details of the contamination problem and the modeling results. Later I will use the field study to answer the following questions: 1) Are reactive transport modeling tools sufficiently reliable for reconstructing historical VOC contamination at field sites? 2) What are the benefits of using reactive transport models for resolving policy problems related to a groundwater risk/exposure assessment problem? Finally, we will use this example to answer a rhetorical question—-how much complexity is too much complexity?

  20. Phreatophyte influence on reductive dechlorination in a shallow aquifer contaminated with trichloroethene (TCE)

    USGS Publications Warehouse

    Lee, R.W.; Jones, S.A.; Kuniansky, E.L.; Harvey, G.; Lollar, B.S.; Slater, G.F.

    2000-01-01

    Phytoremediation uses the natural ability of plants to degrade contaminants in groundwater. A field demonstration designed to remediate aerobic shallow groundwater contaminated with trichloroethene began in April 1996 with the planting of cottonwood trees, a short-rotation woody crop, over an approximately 0.2-ha area at the Naval Air Station, Fort Worth, Texas. The project was developed to demonstrate capture of contaminated groundwater and degradation of contaminants by phreatophytes. Analyses from samples of groundwater collected from July 1997 to June 1998 indicate that tree roots have the potential to create anaerobic conditions in the groundwater that will facilitate degradation of trichloroethene by microbially mediated reductive dechlorination. Organic matter from root exudates and decay of tree roots probably stimulate microbial activity, consuming dissolved oxygen. Dissolved oxygen concentrations, which varied across the site, were smallest near a mature cottonwood tree (about 20 years of age and 60 meters southwest of the cottonwood plantings) where degradation products of trichloroethene were measured. Oxidation of organic matter is the primary microbially mediated reaction occurring in the groundwater beneath the planted trees whereas near the mature cottonwood tree, data indicate that methanogenesis is the most probable reaction occurring. Reductive dechlorination in groundwater either is not occurring or is not a primary process away from the mature tree. Carbon-13 isotope values for trichloroethene are nearly identical at locations away from the mature tree, further confirming that dechlorination is not occurring at the site.

  1. Sorption model of trichloroethylene (TCE) and benezene in municipal landfill materials 

    E-print Network

    Chuang, Yuh-Lin

    1995-01-01

    /C0 = 1) and unsaturated conditions. The sorption rate was found to be proportional to the difference between equilibrium and instantaneous concentration of trace gas on sorbing material. The sorption mechanism predominated at the beginning...

  2. IMPACT OF TURBIDITY ON TCE AND DEGRADATION PRODUCTS IN GROUND WATER

    EPA Science Inventory

    Elevated particulate concentrations in ground water samples can bias contaminant concentration data. This has been particularly problematic for metal analyses where artificially increased turbidity levels can affect metals concentrations and confound interpretation of the data. H...

  3. BIOENHANCED IN-WELL VAPOR STRIPPING TO TREAT TRICHLOROETHYLENE(TCE)

    EPA Science Inventory

    Removal of chlorinated solvent contaminants at their subsurface source is one of the most challenging problems for remediation of these prevalent contaminants. Here, the solvents are generally present as dense non-aqueous phase liquids (DNAPLs). The potential for applicatio...

  4. A Tracer Test to Characterize Treatment of TCE in a Permeable Reactive Barrier

    EPA Science Inventory

    A tracer test was conducted to characterize the flow of ground water surrounding a permeable reactive barrier constructed with plant mulch (a biowall) at the OU-1 site on Altus Air Force Base, Oklahoma. This biowall is intended to intercept and treat ground water contaminated by ...

  5. Spatial And Temporal Distribution Of Microbial Communities In A TCE DNAPL Site: SABRE Field Studies

    EPA Science Inventory

    The SABRE (Source Area BioREmediation) project was conducted to evaluate accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. To study performance of this technology, a test cell was constructed with a longitudi...

  6. RECONSTRUCTING POPULATION EXPOSURES FROM DOSE BIOMARKERS: INHALATION OF TRICHLOROETHYLENE (TCE) AS A CASE STUDY

    EPA Science Inventory

    Physiologically based pharmacokinetic (PBPK) modeling is a well-established toxicological tool designed to relate exposure to a target tissue dose. The emergence of federal and state programs for environmental health tracking and the availability of exposure monitoring through bi...

  7. t--.-----_I__--+ eA Science ServTce Yeature

    E-print Network

    the explorers enjoyed baskin& in the sunshine, a i d even went to s l e q on the o;3en deck. recorded a temperature below freeziw Thou& the thermometer the air was calm and the sunshine f e l t quite hot. While

  8. SABRE MULTI-LAB, STATISTICALLY-BASED MICROCOSM STUDY FOR TCE SOURCE ZONE REMEDIATION (ABSTRACT ONLY)

    EPA Science Inventory

    SABRE (source area bioremediation) is a public/private consortium of twelve companies, two government agencies, and three research institutions whose charter is to determine if enhanced anaerobic bioremediation can result in effective and quantifiable treatment of chlorinated sol...

  9. 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...

  10. BENCH-SCALE PERFORMANCE OF PARTITIONING ELECTRON DONORS FOR TCE DNAPL BIOREMEDIATION

    EPA Science Inventory

    The objective of the Source Area Bioremediation (SABRE) project, an international collaboration of twelve companies, two government agencies and three research institutions, is to evaluate the performance of enhanced anaerobic bioremediation for the treatment of chlorinated ethen...

  11. Characterizing The Microbial Community In A TCE DNAPL Site: SABRE Column And Field Studies

    EPA Science Inventory

    The SABRE (Source Area BioREmediation) project is evaluating accelerated anaerobic bioremediation of chlorinated solvents in areas of high concentration, such as DNAPL source areas. In support of a field scale pilot test, column studies were conducted to design the system and ob...

  12. EFFECTIVE REMOVAL OF TCE IN A LABORATORY MODEL OF A PRB CONSTRUCTED WITH PLANT MULCH

    EPA Science Inventory

    In the past ten years, passive reactive barriers (PRBs) have found widespread application to treat chlorinated solvent contamination in ground water. The traditional PRB commonly uses granular zero-valent iron and/or iron alloys as filling materials for treatment of chlorinated ...

  13. PLANT MULCH TO TREAT TCE IN GROUND WATER IN A PRB (ABSTRACT ONLY)

    EPA Science Inventory

    In the past ten years, passive reactive barriers (PRBs) have found widespread application to treat chlorinated solvent contamination in ground water. The traditional PRB commonly uses granular zero-valent iron and/or iron alloys as filling materials for treatment of chlorinated ...

  14. PLANT MULCH TO TREAT TCE IN GROUND WATER IN A PRB

    EPA Science Inventory

    In the past ten years, passive reactive barriers (PRBs) have found widespread application to treat chlorinated solvent contamination in ground water. The traditional PRB commonly uses granular zero-valent iron and/or iron alloys as filling materials for treatment of chlorinated ...

  15. Chemically enhanced mixed region vapor stripping of TCE-contaminated saturated peat and silty clay soils

    SciTech Connect

    West, O.R.; Cameron, P.A.; Lucero, A.J.; Koran, L.J. Jr.

    1996-01-01

    The objective of this study was to conduct further testing of MRVS, chemically enhanced with calcium oxide conditioning, on field- contaminated soils collected from beneath the NASA Michoud Rinsewater Impoundment. In this study, residual soil VOC levels as a function of vapor stripping time were measured to quantify VOC removal rates. Physical and chemical soil parameters expected to affect MRVS efficiency were measures. The effects of varying the calcium oxide loadings as well as varying the vapor stripping flow rates on VOC removal were also evaluated. The results of this study will be used to determine whether acceptable removals can be achieved within reasonable treatment times, remediation costs being directly proportional to the latter. The purpose of this report is to document the experimental results of this study, as well as to address issues that were raised after completion of the previous Michoud treatability work.

  16. Sustainability of TCE Removal in the Mulch Biowalls at Altus AFB

    EPA Science Inventory

    A permeable mulch biowall was installed in June 2002 at Landfill 3 (LF-03), Operable Unit 1 (OU-1), Altus AFB, Oklahoma. The demonstration was conducted by Parsons for the AFCEE Technology Transfer Outreach Office. The biowall is approximately 455 feet long, by 24 feet deep, by...

  17. The use of biofilters to improve indoor air quality: the removal of toluene, TCE, and formaldehyde.

    PubMed

    Darlington, A; Dixon, M A; Pilger, C

    1998-01-01

    A biofilter composed of a scrubber, a hydroponic planting system, and an aquatic system with green plants as a base maintained air quality within part of a modern office building. The scrubber was composed of five parallel fiberglass modules with external faces of porous lava rock. The face, largely covered with mosses, was wetted by recirculating water. Air was drawn through the scrubber and the immediately adjacent hydroponic region by a dedicated air handling system. The system was challenged for 4 weeks with three common indoor organic pollutants and removed significant amounts of all compounds. A single pass through the scrubber removed 10% of the trichloroethylene and 50% of the toluene. A single pass lowered formaldehyde air concentrations to 13 micrograms m-3 irrespective of influent levels (ranging between 30 and 90 micrograms m-3). The aquatic system accumulated trichloroethylene but neither toluene nor formaldehyde, suggesting the rapid breakdown of these materials. The botanical components removed some pollutants. PMID:11540466

  18. The impact of additives found in industrial formulations of TCE on the wettability of sandstone

    E-print Network

    Sheffield, University of

    of Greenwich, Pembroke, Chatham Maritime, Kent ME4 4TB, UK b Groundwater Protection and Restoration Group.a.leharne@gre.ac.uk (S.A. Leharne). Journal of Contaminant Hydrology 80 (2005) 1­17 www.elsevier.com/locate/jconhyd #12 common and insidious of groundwater contaminants (Lohman, 2002; Mackay and Cherry, 1989). This situation

  19. Treatability of TCE-contaminated clay soils at the Rinsewater Impoundment, Michoud Assembly Facility

    SciTech Connect

    Lucero, A.J.; Gilbert, V.P.; Hewitt, J.D.; Koran, L.J. Jr.; Jennings, H.L.; Donaldson, T.L.; West, O.R.; Cline, S.R.; Marshall, D.S.

    1995-02-01

    The Oak Ridge National Laboratory has conducted treatability studies on clay soils taken from the Rinsewater Impoundment at the National Aeronautics and Space Administration Michoud Assembly Facility. The soils are contaminated with up to 3000 mg/kg of trichloroethylene and cis-1,2-dichloroethylene, less than 10 mg/kg of trans-1,2-DCE, and less than 10 mg/kg of vinyl chloride. The goal of the study described in this report was to identify and test in situ technologies and/or develop a modified treatment regime to remove or destroy volatile organic compounds from the contaminated clay soils. Much of the work was based upon previous experience with mixed-region vapor stepping and mixed-region peroxidation. Laboratory treatments were performed on intact soil cores that were taken from contaminated areas at the Rinsewater Impoundment at MAF. Treatability studies were conducted on soil that was close to in situ conditions in terms of soil structure and contaminant concentrations.

  20. 76 FR 13182 - Settlement Agreement for Recovery of Past Response Costs; 345 North 700 East, Richfield PCE Site...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-10

    ... the Settling Parties have no ability to pay and the Settling Parties (1) agree not to assert any... Agreement should be addressed to Virginia G. Phillips, Enforcement Specialist (8ENF-RC), Technical...: Virginia Phillips, Enforcement Specialist, (8ENF-RC), Technical Enforcement Program, U.S....

  1. Fluid and porous media property effects on dense nonaqueous phase liquid migration and contaminant mass flux.

    PubMed

    Totten, C T; Annable, M D; Jawitz, J W; Delfinot, J J

    2007-03-01

    The effects of fluid and porous media properties on dense nonaqueous phase liquid (DNAPL) migration and associated contaminant mass flux generation were evaluated. Relationships between DNAPL mass and solute mass flux were generated by measuring steady-state mass flux following stepwise injection of perchloroethylene (PCE) into flow chambers packed with homogeneous porous media. The effects of fluid properties including density and interfacial tension (IFT), and media properties including grain size and wettability were evaluated by varying the density contrast and interfacial tension properties between PCE and water, and by varying the porous media mean grain diameter and wettability characteristics. Contaminant mass flux was found to increase as grain size decreased, suggesting enhanced lateral and vertical DNAPL spreading with higher fluid entry pressure. Mass flux showed a slight increase as the DNAPL approached neutral buoyancy, likely due to enhanced vertical spreading above the injection point. DNAPL spatial distribution and contaminant mass flux were only minimally affected by IFT and by intermediate-level wettability changes, but were dramatically affected by wettability reversal. The relationship between DNAPL loading and flux generation became more linear as grain size decreased and density contrast between fluids decreased. These results imply that capillary flow characteristics of the porous media and fluid properties will control mass flux generation from source zones. PMID:17396651

  2. Complete detoxification of short chain chlorinated aliphatic compounds: Isolation of halorespiring organisms and biochemical studies of the dehalogenating enzyme systems. 1998 annual progress report

    SciTech Connect

    Tiedje, J.M.

    1998-06-01

    'Widespread use and careless handling, storage and disposal practices, have lead to the dissemination of chlorinated short chain aliphatics into groundwater systems. These compounds are toxic and the presence of chlorinated ethenes and chlorinated propanes in the environment is of public concern. Halorespiration is a newly recognized anaerobic process by which certain bacteria use chlorinated compounds as terminal electron acceptors in their energy metabolism. In contrast to co-metabolic dechlorination, which is fortuitous, slow, and without benefit to the organisms, halorespiration, characterized by high dechlorination rates, is a specific metabolic process beneficial to the organism. The goals are to isolate and characterize organisms which use chlorinated ethenes (including tetrachloroethene [PCE], trichloroethene [TCE], cis-dichloroethene [cis-DCE], and vinyl chloride [VC], or 1,2-dichloropropane [1,2-D]) as electron acceptors in their energy metabolism. Better understanding of the physiology and phylogeny of the halorespiring organisms as well as the biochemistry of the dehalogenating enzyme systems, will greatly enhance the authors knowledge of how these organisms can successfully be employed in the bioremediation of contaminated sites. This report summarizes the results of 1.5 years of a 2-year project. Anaerobic microcosms were established using a variety of geographically distinct sediments. In several microcosms complete dechlorination of PCE to ethene (ETH), and 1,2-D to propene was observed. Upon subsequent transfers to anaerobic medium, four sediment-free, methanogenic enrichment cultures were obtained that dechlorinated PCE to ETH, and two cultures that dechlorinated 1,2-D to propene. 2-Bromoethanesulfonate (BES), a well known inhibitor of methanogens, did not inhibit the dechlorination of 1,2-D to propene or the dechlorination of PCE to cis-DCE. However, the complete dechlorination of PCE to VC and ETH was severely inhibited. They could also show that BES inhibited the dechlorination of chloroethenes in cultures without methanogens. Therefore, BES should not be used to attribute dechlorination activities to methanogens.'

  3. Characterization of anaerobic chloroethene-dehalogenating activity in several subsurface sediments

    SciTech Connect

    Skeen, R.S.; Gao, J.; Hooker, B.S.; Quesenberry, R.D.

    1996-11-01

    Anaerobic microcosms of subsurface soils from four locations were used to investigate the separate effects of several electron donors on tetrachloroethylene (PCE) dechlorination activity. The substrates tested were methanol, formate, lactate, acetate, and sucrose. Various levels of sulfate-reducing, acetogenic, fermentative, and methanogenic activity were observed in all sediments. PCE dechlorination was detected in all microcosms, but the amount of dehalogenation varied by several orders of magnitude. Trichloroethylene was the primary dehalogenation product; however, small amounts of cis-1,2-dichloroethylene, 1,1-dichloroethylene, and vinyl chloride were also detected in several microcosms. Lactate-amended microcosms showed large amounts of dehalogenation. in three of the four sediments. One of the two sediments which showed positive activity with lactate also had large amounts of delialogenation with methanol. Sucrose, formate, and acetate also stimulated large amounts of delialogenation in one sediment that showed activity with lactate. These results suggest that lactate may be an appropriate substrate for screening sediments for PCE or TCE delialogenation activity, but that the microbial response is not sufficient for complete in situ bioremediation. A detailed study of the Victoria activity revealed that delialogenation rates were more similar to the Cornell culture than to rates measured for methanogens, or a methanol-enriched sediment culture. This may suggest that these sediments contain a highly efficient delialogenation activity similar to the Cornell culture. This assertion is supported further by the fact that an average of 3% of added reducing equivalents could be diverted to dehalogenation in tests which were conducted using PCE-saturated hexadecane as a constant source of PCE during incubation. Further evidence is needed to confirm this premise. The application of these results to in situ bioremediation of highly contaminated areas are discussed.

  4. DESORPTION BEHAVIOR OF TRICHLOROETHENE AND TETRACHLOROETHENE IN U.S. DEPARTMENT OF ENERGY SAVANNAH RIVER SITE UNCONFINED AQUIFER SEDIMENTS

    SciTech Connect

    Vangelas, K; Robert G. Riley, R; James E. Szecsody, J; A. V. Mitroshkov, A; C. F. Brown, C; Brian02 Looney, B

    2007-01-10

    Sorption is governed by the physico-chemical processes that partition solutes between the aqueous and solid phases in aquifers. For environmental systems, a linear equilibrium relationship between the amount of contaminant in the alternative phases is often assumed. In this traditional approach, the distribution coefficient, or K{sub d}, is a ratio of contaminant associated with the solid phase to the contaminant in the water phase. Recent scientific literature has documented time-dependant behaviors in which more contaminant mass is held in the solid phase than predicted by the standard model. Depending on the specific conceptualization, this has been referred to as nonlinear sorption, time-variable sorption, or ''irreversible sorption''. The potential impact of time-variable sorption may be beneficial or detrimental depending on the specific conditions and remediation goals. Researchers at the Pacific Northwest National Laboratory (PNNL) have been studying this process to evaluate how various soil types will affect this process for sites contaminated with chlorinated solvents. The results described in this report evaluate sorption-desorption of trichloroethylene (TCE) and tetrachloroethylene (PCE) in Savannah River Site (SRS) soils. The results of this study will be combined with ongoing PNNL research to provide a more comprehensive look at this process and its impact on contaminant plume stability and sustainability. Importantly, while the results of the study documented differences in sorption properties between two tested SRS soils, the data indicated that ''irreversible sorption'' is not influencing the sorption-desorption behaviors of TCE and PCE for these soils.

  5. Field test of single well DNAPL characterization using alcohol injection/extraction

    SciTech Connect

    Jerome, K.M.; Looney, B.B.; Rhoden, M.L.; Riha, B.; Burdick, S.

    1996-10-29

    Soils and groundwater beneath an abandoned process sewer line in the A/M Area of the Savannah River Site (SRS) contain elevated levels of volatile organic compounds, specifically trichloroethylene (TCE) and tetrachloroethylene (PCE), two common chlorinated solvents. These compounds have low aqueous solubilities, thus when released to the subsurface in sufficient quantity, tend to exist as immiscible fluids or nonaqueous phase liquids (NAPLs). Because chlorinated solvents are also denser than water, they are referred to by the acronym DNAPLs, or dense non-aqueous phase liquids. Technologies targeted at efficient characterization or removal of DNAPL are not currently proven. The authors performed injection/extraction characterization tests in six existing wells in A/M Area. Water concentrations for TCE and/or PCE in these wells ranged from 0% to 100% of solubility. For each test, small amounts of solubilizing solution were used to try to confirm or deny the presence or absence of DNAPL in the immediate vicinity of the well screen.

  6. Phytomonitoring of chlorinated ethenes in trees: a four-year study of seasonal chemodynamics in planta.

    PubMed

    Limmer, Matt A; Holmes, Amanda J; Burken, Joel G

    2014-09-16

    Long-term monitoring (LTM) of groundwater remedial projects is costly and time-consuming, particularly when using phytoremediation, a long-term remedial approach. The use of trees as sensors of groundwater contamination (i.e., phytoscreening) has been widely described, although the use of trees to provide long-term monitoring of such plumes (phytomonitoring) has been more limited due to unexplained variability of contaminant concentrations in trees. To assess this variability, we developed an in planta sampling method to obtain high-frequency measurements of chlorinated ethenes in oak (Quercus rubra) and baldcypress (Taxodium distichum) trees growing above a contaminated plume during a 4-year trial. The data set revealed that contaminant concentrations increased rapidly with transpiration in the spring and decreased in the fall, resulting in perchloroethene (PCE) and trichloroethene (TCE) sapwood concentrations an order of magnitude higher in late summer as compared to winter. Heartwood PCE and TCE concentrations were more buffered against seasonal effects. Rainfall events caused negligible dilution of contaminant concentrations in trees after precipitation events. Modeling evapotranspiration potential from meteorological data and comparing the modeled uptake and transport with the 4 years of high frequency data provides a foundation to advance the implementation of phytomonitoring and improved understanding of plant contaminant interactions. PMID:25140854

  7. Aerobic biodegradation of chlorinated ethenes in a fractured bedrock aquifer: quantitative assessment by compound-specific isotope analysis (CSIA) and reactive transport modeling.

    PubMed

    Pooley, Kathryn E; Blessing, Michaela; Schmidt, Torsten C; Haderlein, Stefan B; Macquarrie, Kerry T B; Prommer, Henning

    2009-10-01

    A model-based analysis of concentration and isotope data was carried out to assess natural attenuation of chlorinated ethenes in an aerobic fractured bedrock aquifer. Tetrachloroethene (PCE) concentrations decreased downgradient of the source, but constant delta13C signatures indicated the absence of PCE degradation. In contrast, geochemical and isotopic data demonstrated degradation of trichloroethene (TCE) and cis-1,2-dichloroethene (DCE) under the prevailing oxic conditions. Numerical modeling was employed to simulate isotopic enrichment of chlorinated ethenes and to evaluate alternative degradation pathway scenarios. Existing field information on groundwater flow, solute transport, geochemistry, and delta13C signatures of the chlorinated ethenes was integrated via reactive transport simulations. The results provided strong evidence for the occurrence of aerobic TCE and DCE degradation. The chlorinated ethene concentrations together with stable carbon isotope data allowed us to reliably constrain the assessment of the extent of biodegradation at the site and plume simulations quantitatively linked aerobic biodegradation with isotope signatures in the field. Our investigation provides the first quantitative assessment of aerobic biodegradation of chlorinated ethenes in a fractured rock aquifer based on compound specific stable isotope measurements and reactive transport modeling. PMID:19848161

  8. Chlorinated solvents in groundwater of the United States

    USGS Publications Warehouse

    Moran, M.J.; Zogorski, J.S.; Squillace, P.J.

    2007-01-01

    Four chlorinated solvents-methylene chloride, perchloroethene (PCE), 1,1,1-trichloroethane, and trichloroethene (TCE)-were analyzed in samples of groundwater taken throughout the conterminous United States by the U.S. Geological Survey. The samples were collected between 1985 and 2002 from more than 5,000 wells. Of 55 volatile organic compounds (VOCs) analyzed in groundwater samples, solvents were among the most frequently detected. Mixtures of solvents in groundwater were common and may be the result of common usage of solvents or degradation of one solvent to another. Relative to other VOCs with Maximum Contaminant Levels (MCLs), PCE and TCE ranked high in terms of the frequencies of concentrations greater than or near MCLs. The probability of occurrence of solvents in groundwater was associated with dissolved oxygen content of groundwater, sources such as urban land use and population density, and hydraulic properties of the aquifer. The results reinforce the importance of understanding the redox conditions of aquifers and the hydraulic properties of the saturated and vadose zones in determining the intrinsic susceptibility of groundwater to contamination by solvents. The results also reinforce the importance of controlling sources of solvents to groundwater. ?? 2007 American Chemical Society.

  9. Carbon isotope fractionation of chlorinated ethenes during oxidation by Fe2+ activated persulfate.

    PubMed

    Marchesi, Massimo; Aravena, Ramon; Sra, Kanwartej S; Thomson, Neil R; Otero, Neus; Soler, Albert; Mancini, Silvia

    2012-09-01

    The increased use of persulfate (S(2)O(8)(2-)) for in situ chemical oxidation to treat groundwater and soils contaminated by chlorinated hydrocarbon compounds (CHCs) requires unbiased methods to assess treatment performance. Stable carbon isotope analysis offers a potential tool for assessing the in situ treatment performance of persulfate at sites contaminated with CHCs. This study investigated the extent of C isotope fractionation during oxidation of tetrachloroethene (PCE), trichloroethene (TCE) and cis-dichloroethene (cis-DCE) by persulfate activated by ferrous ion (Fe(2+)). An average carbon isotope enrichment factor ?(bulk) of -4.9‰ for PCE, -3.6‰ for TCE and -7.6‰ for cis-DCE were obtained in batch experiments. Variations in the initial S(2)O(8)(2-)/Fe(2+)/CHC molar ratios did not result in any significant differences in carbon isotope fractionation. The occurrence of carbon isotope fractionation during oxidation and the lack of dependence of enrichment factors upon the S(2)O(8)(2-)/Fe(2+)/CHC molar ratio demonstrate that carbon isotope analysis can potentially be used at contaminated sites as an additional technique to estimate treatment efficacy during oxidation of CHCs by Fe(2+) activated persulfate. PMID:22814410

  10. Extraction methods for recovery of volatile organic compounds from fortified dry soils

    SciTech Connect

    Minnich, M.M.; Zimmerman, J.H.; Schumacher, B.A.

    1996-09-01

    Recovery of 8 volatile organic compounds (VOCs) from dry soils, each fortified at 800 ng/g soil, was studied in relation to the extraction method and time of extraction. Extraction procedures studied on 2 desiccator-dried soils were modifications of EPA low- and high-level purge-and-trap extractions (SW-846 Method 5030A): treatment 1, unmodified low-level procedure; treatment 2, 18 h water presoak followed by low-level procedure; treatment 3, 24 h methanol extract at room temperature followed by high-level procedure; and treatment 4, 24 h methanol extract at 65{degrees}C followed by high-level procedure. VOC recoveries from replicate soil samples increased in the treatment order 1 through 4. With Charleston soil (8% clay and 3.8% organic carbon), highly significant differences (p {le} 0.001) in recoveries among treatments were observed for trichloroethene (TCE), tetrachloroethene (PCE), toluene, ethylbenzene, and o-xylene, with 2- to 3-fold increased recoveries between treatments 1 and 3. With Hayesville soil (32% clay and 0.2% organic carbon), significant improvements (p{le}0.05) in recoveries of toluene, ethylbenzene, o-oxylene, 1,1,1-trichloroethane, TCE, and PCE were observed for heated methanol (treatment 4) rather than water extraction (treatment 1), but the increases were less than 2-fold. 19 refs., 1 fig., 5 tabs.

  11. Modeling natural attenuation of chlorinated solvent plumes at the Dover Air Force Base Area-6 site

    SciTech Connect

    Clement, P; Johnson, Christian D. ); Sun, Y; Klecka, Gary M.; Bartlett, Craig; B.C. Alleman and A. Leeson

    1999-01-01

    A multi-dimensional, multi-species reactive transport code, RT3D, was used to aid in the analysis of natural attenuation design at the Dover AFB site. The RT3D code is a general-purpose numerical solver that can be used to solve any type of reactive transport systems by specifying a system-specific reaction model (Clement, 1997; Clement et al., 1998). In this study, a detailed biochemical reaction model was developed to simulate all aerobic and anaerobic reactions that occur at the Dover AFB site. The reactions were integrated into RT3D and the resulting numerical code was used to simulate the bioreactive transport occurring at the site. Through a model calibration process, field-scale decay rates of PCE/TCE and their degradation products were estimated. The calibrated model also successfully recreated the observed distribution of PCE, TCE, DCE, VC and chloride plumes. Sensitivity analysis of the calibrated model was performed to quantify the importance of model parameters. The simulation model developed in this work is a useful framework for analyzing chlorinated-solvent natural attenuation data.

  12. Stable Carbon Isotope Evidence and Quantification of Reductive Dechlorination of Chlorinated Ethenes at Kelly AFB, TX

    NASA Astrophysics Data System (ADS)

    Morrill, P.; Lacrampe-Couloume, G.; Slater, G.; Sleep, B.; Edwards, E.; McMaster, M.; Major, D.; Sherwood Lollar, B.

    2002-12-01

    Cis-1, 2-dichloroethene (cDCE) was the primary volatile organic compound (VOC) after biostimulation of a perchloroethene (PCE) plume in a pilot test at Kelly Air Force Base (AFB) in San Antonio Texas. A stable natural microbial consortium, KB-1, shown in laboratory experiments to reduce chlorinated ethenes to non-toxic ethene was added in a pilot test area (PTA). After the addition of KB-1 stable carbon isotope values were measured for each chlorinated ethene to verify the occurrence of reductive dechlorination and quantify the extent of cDCE degradation. After bioaugmentation with KB-1, PCE, TCE and cDCE concentrations declined, while VC concentrations increased and subsequently decreased, as ethene became the dominant transformation product measured. Shifts in carbon isotopic values up to 2.7 permil, 6.4 permil, 10.9 permil and 10.6 permil were observed for PCE, TCE, cDCE and VC respectively. These isotopic shifts are consistent with the effects of biodegradation observed during laboratory and field studies. Most notably, isotopic enrichment trends characteristic of reductive dechlorination were detectable in the parent compounds before measurable concentrations of daughter products VC and ethene were produced. These results illustrate the advantage of using the more sensitive compound specific isotope analysis to confirm degradation in addition to the traditional method of monitoring the appearance of degradation products. Fractionation factors obtained from laboratory studies were used in conjunction with isotope data measured in the field to estimate the extent of cDCE degraded. It is estimated that within a 44 day period, 37 to 48 percent of the cDCE was reductively dechlorinated. Independent biodegradation estimates using data from a bromide tracer test, a groundwater flow model, and concentration analyses were all in good agreement with the isotope degradation estimate.

  13. Multi-isotope (carbon and chlorine) analysis for fingerprinting and site characterization at a fractured bedrock aquifer contaminated by chlorinated ethenes.

    PubMed

    Palau, Jordi; Marchesi, Massimo; Chambon, Julie C C; Aravena, Ramon; Canals, Àngels; Binning, Philip J; Bjerg, Poul L; Otero, Neus; Soler, Albert

    2014-03-15

    The use of compound specific multi-isotope approach (C and Cl) in the characterization of a chlorinated ethenes contaminated fractured aquifer allows the identification of several sources and contaminant plumes, as well as the occurrence of biodegradation and mixing processes. The study site is located in Spain with contamination resulting in groundwater concentrations of up to 50mg/L of trichloroethene (TCE), the most abundant chlorinated ethene, and 7 mg/L of tetrachloroethene (PCE). The potential sources of contamination including abandoned barrels, an underground tank, and a disposal lagoon, showed a wide range in ?(13)C values from -15.6 to -40.5‰ for TCE and from -18.5 to -32.4‰ for PCE, allowing the use of isotope fingerprinting for tracing of the origin and migration of these contaminants in the aquifer. In contrast, there is no difference between the ?(37)Cl values for TCE in the contaminant sources, ranging from +0.53 to +0.66‰. Variations of ?(37)Cl and ?(13)C in the different contaminant plumes were used to investigate the role of biodegradation in groundwater. Moreover, the isotopic data were incorporated into a reactive transport model for determination of whether the isotope pattern observed downstream from the tank's source could be explained by the simultaneous effect of mixing and biodegradation. The results demonstrate that a multi-isotope approach is a valuable tool for characterization of complex sites such as fractured bedrock aquifer contaminated by multiple sources, providing important information which can be used by consultants and site managers to prioritize and design more successful remediation strategies. PMID:24419287

  14. Alternative Methods for Assessing Contaminant Transport from the Vadose Zone to Indoor Air

    NASA Astrophysics Data System (ADS)

    Baylor, K. J.; Lee, A.; Reddy, P.; Plate, M.

    2010-12-01

    Vapor intrusion, which is the transport of contaminant vapors from groundwater and the vadose zone to indoor air, has emerged as a significant human health risk near hazardous waste sites. Volatile organic compounds (VOCs) such as trichloroethylene (TCE) and tetrachloroethylene (PCE) can volatilize from groundwater and from residual sources in the vadose zone and enter homes and commercial buildings through cracks in the slab, plumbing conduits, or other preferential pathways. Assessment of the vapor intrusion pathway typically requires collection of groundwater, soil gas, and indoor air samples, a process which can be expensive and time-consuming. We evaluated three alternative vapor intrusion assessment methods, including 1) use of radon as a surrogate for vapor intrusion, 2) use of pressure differential measurements between indoor/outdoor and indoor/subslab to assess the potential for vapor intrusion, and 3) use of passive, longer-duration sorbent methods to measure indoor air VOC concentrations. The primary test site, located approximately 30 miles south of San Francisco, was selected due to the presence of TCE (10 - 300 ug/L) in shallow groundwater (5 to 10 feet bgs). At this test site, we found that radon was not a suitable surrogate to asses vapor intrusion and that pressure differential measurements are challenging to implement and equipment-intensive. More significantly, we found that the passive, longer-duration sorbent methods are easy to deploy and compared well quantitatively with standard indoor air sampling methods. The sorbent technique is less than half the cost of typical indoor air methods, and also provides a longer duration sample, typically 3 to 14 days rather than 8 to 24 hours for standard methods. The passive sorbent methods can be a reliable, cost-effective, and easy way to sample for TCE, PCE and other VOCs as part of a vapor intrusion investigation.

  15. Chlorinated organic compounds in ground water at Roosevelt Field, Nassau County, Long Island, New York

    USGS Publications Warehouse

    Eckhardt, D.A.; Pearsall, K.A.

    1989-01-01

    Trichloroethylene (TCE), 1,2-dichloroethylene (DCE), and tetrachloroethylene (PCE) have been detected in water from five public-supply wells and six cooling-water wells that tap the Magothy aquifer at Roosevelt Field, a 200-acre area that is now a large shopping mall and office-building complex. The cooling water is discharged after use to the water table (upper glacial) aquifer through a nearby recharge basin and a subsurface drain field. Three plumes of TCE in groundwater have been delineated--the source plume, which has penetrated both aquifers , and two more recent plumes emanating from the two discharge sites in the water-table aquifer. Concentrations of inorganic constituents in the three plumes are the same as those in ambient water in the area. The two secondary plumes discharged cooling water extended at least 1,000 ft south-southeastward in the direction of regional groundwater flow. Pumping at wells screened in the middle and basal sections of the Magothy aquifers, where clay layers are absent and sandy zones provide good vertical hydraulic connection within the aquifer system, has increased the rate of downward contaminant advection. The transient increases in downward movement are cumulative over time and have brought TCE to the bottom of the Magothy aquifer, 500 ft below land surface. (USGS)

  16. Complete detoxification of short chain chlorinated aliphatics: Isolation of halorespiring organisms and biochemical studies of the dehalogenating enzyme systems. 1997 annual progress report

    SciTech Connect

    Loeffler, F.E.; Tiedje, J.M.

    1997-01-01

    'The objectives of the research within this grant are: (1) Isolation and characterization of chlororespiring organisms responsible for the complete dehalogenation of chlorinated ethenes and propanes. (2) Development of conditions that yield high cell densities and induce dechlorinating activity. (3) Development of assay systems to detect the dechlorinating activity in cell-free extracts. (4) Purification and characterization of the dehalogenating enzymes. Anaerobic microcosms were obtained from a variety of geographically different sediment samples. In several microcosms complete dechlorination of tetrachloroethene (PCE) to ethene (ETH), and 1,2-dichloropropane ( 1,2-D) and/or 1,2,3-trichloropropane to propene was observed. Upon subsequent transfers to anaerobic medium, sediment-free, methanogenic enrichment cultures were obtained that dechlorinated PCE to ETH, and 1,2-D to propene, respectively. 2-Bromoethanesulfonate (BES), a well known inhibitor of methanogens, did not inhibit the dechlorination of 1,2-D to propene and the dechlorination of PCE to cis-dichloroethene (cis-DCE). However,-the complete dechlorination of PCE to vinyl chloride (VC) and ETH was severely inhibited. The authors could show that BES inhibited the dechlorination of chloroethenes in cultures not containing methanogens. Previous to this study, BES was believed to be aspecific inhibitor of methanogens and the inhibitory effect of BES on declorination was explained by the involvement of methanogens in the dechlorination process. The non-methanogenic cultures obtained after the BES treatment were subsequently transferred to medium riot containing BES and complete dechlorination of PCE to ETH was observed as was in the original microcosms. Subcultures were further enriched with PCE, cis-DCE, VC, or 1,2-D as the only available electron acceptor and acetate, or acetate plus hydrogen as the only available electron donor(s). To date these cultures have undergone up to 45 transfers. Interestingly, two cultures that originally dechlorinated PCE to ETH, but were then enriched with cis-DCE or VC, lost their ability to-dechlorinate PCE or TCE. This finding indicates that different populations are involved in the complete dechlorination of PCE to ETH in these cultures. In contrast, one culture that was enriched with cis-DCE and VC, respectively, maintained its ability to dechlorinate PCE. Using molecular tools ({sup 16}S rDNA targeted PCR,TA cloning of {sup 1}6S rDNA genes, ARDRA analysis and sequencing) they showed that this culture consisted of three distinct organisms. Two of them could be isolated in pure Culture but neither of them showed any dechlorinating activity, indicating that one organism was responsible for the complete dechlorination of PCE to ETH in the mixed culture. The authors are currently focusing on the isolation and phylogenetic characterization of this organism.'

  17. Relating mRNA and protein biomarker levels in a Dehalococcoides and Methanospirillum-containing community.

    PubMed

    Rowe, Annette R; Mansfeldt, Cresten B; Heavner, Gretchen L; Richardson, Ruth E

    2015-03-01

    To better understand the quantitative relationships between messenger RNA (mRNA) and protein biomarkers relevant to bioremediation, we quantified and compared respiration-associated gene products in an anaerobic syntrophic community. Respiration biomarkers for Dehalococcoides, an organohalide reducer, and Methanospirillum, a hydrogenotrophic methanogen, were quantified via qRT-PCR for mRNA and multiple reaction monitoring (MRM) of proteotypic peptides for protein. mRNA transcripts of the Dehalococcoides reductive dehalogenases PceA, TceA, and DMC1545, and hydrogenase HupL, as well as the Methanospirillum oxidoreductases MvrD and FrcA were shown to be similarly regulated with respect to their temporal responses to substrate addition. However, MvrD was two orders of magnitude lower in mRNA abundance. Per cell, Dehalococcoides protein biomarkers quantified were more abundant than Methanospirillum proteins. Comparing mRNA with protein abundance, poor correlations were observed between mRNA transcript levels and the net protein produced. For example, Dehalococcoides HupL and TceA transcripts were similarly abundant though TceA was far more abundant at the protein level (167?±?121 vs. 1095?±?337 proteins per cell, respectively). In Methanospirillum, MvrD maintained comparable per-cell protein abundance to FrcA (42?±?14 vs. 60?±?1 proteins per cell, respectively) despite the significantly lower transcript levels. Though no variability in protein decay rates was observed, the mRNA translation rate quantified for TceA was greater than the other Dehalococcoides targets monitored. These data suggest that there is considerable variation in the relationship between mRNA abundance and protein production both across transcripts within an organism and across organisms. This highlights the importance of empirically based studies for interpreting biomarker levels in environmentally relevant organisms. PMID:25467924

  18. Feasibility of dibromochloropropane (DBCP) and trichloroethylene (TCE) adsorption onto activated carbons made from nut shells of different almond varieties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Steam-activated carbons were made from shells from five different almond varieties (‘Nonpareil,’ ‘Padre,’ Tuono,’ ‘23-122,’ and ‘Y120-74’) and from a mix of almond types. The purpose of the work was to evaluate if the composition of shells had any effect on the performance of the final product. The ...

  19. Transformation of Reactive Iron Minerals in a Permeable Reactive Barrier (Biowall) Used to Treat TCE in Groundwater

    EPA Science Inventory

    Abstract: Iron and sulfur reducing conditions are generally created in permeable reactive barrier (PRB) systems constructed for groundwater treatment, which usually leads to formation of iron sulfide phases. Iron sulfides have been shown to play an important role in degrading ch...

  20. APPLICATION AND USE OF DOSE ESTIMATING EXPOSURE MODEL (DEEM) FOR DOSE COMPARISONS AFTER EXPOSURE TO TRICHLOROETHYLENE (TCE)

    EPA Science Inventory

    Route-to-route extrapolations are a crucial step in many risk assessments. Often the doses which result In toxicological end points in one route must be compared with doses resulting from typical environmental exposures by another route. In this case we used EPA's Dose Estimati...

  1. APPLICATION AND USE OF DOSE ESTIMATING EXPOSURE MODEL (DEEM) FOR ROUTE TO ROUTE DOSE COMPARISONS AFTER EXPOSURE TO TRICHLOROETHYLENE (TCE)

    EPA Science Inventory

    Route-to-route extrapolations are a crucial step in many risk assessments. Often the doses which result In toxicological end points in one route must be compared with doses resulting from typical environmental exposures by another route. In this case we used EPA's Dose Estimati...

  2. Electron transfer from a solid-state electrode assisted by methyl viologen sustains efficient microbial reductive dechlorination of TCE.

    PubMed

    Aulenta, Federico; Catervi, Alessandro; Majone, Mauro; Panero, Stefania; Reale, Priscilla; Rossetti, Simona

    2007-04-01

    The ability to transfer electrons, via an extracellular path, to solid surfaces is typically exploited by microorganisms which use insoluble electron acceptors, such as iron-or manganese-oxides or inert electrodes in microbial fuel cells. The reverse process, i.e., the use of solid surfaces or electrodes as electron donors in microbial respirations, although largely unexplored, could potentially have important environmental applications, particularly for the removal of oxidized pollutants from contaminated groundwater or waste streams. Here we show, for the first time, that an electrochemical cell with a solid-state electrode polarized at -500 mV (vs standard hydrogen electrode), in combination with a low-potential redox mediator (methyl viologen), can efficiently transfer electrochemical reducing equivalents to microorganisms which respire using chlorinated solvents. By this approach, the reductive transformation of trichloroethene, a toxic yet common groundwater contaminant, to harmless end-products such as ethene and ethane could be performed. Furthermore, using a methyl-viologen-modified electrode we could even demonstrate that dechlorinating bacteria were able to accept reducing equivalents directly from the modified electrode surface. The innovative concept, based on the stimulation of dechlorination reactions through the use of solid-state electrodes (we propose for this process the acronym BEARD: Bio-Electrochemically Assisted Reductive Dechlorination), holds promise for in situ bioremediation of chlorinated-solvent-contaminated groundwater, and has several potential advantages over traditional approaches based on the subsurface injection of organic compounds. The results of this study raise the possibility that immobilization of selected redox mediators may be a general strategy for stimulating and controlling a range of microbial reactions using insoluble electrodes as electron donors. PMID:17438815

  3. Destruction of TCE Using Oxidative and Reductive Pathways as Potential In-Situ Treatments for the Contaminated Paducah Groundwater

    SciTech Connect

    Lewis, S; Li, Y; Xu, J; Tee, Y; Lynch, Andrew

    2007-05-01

    When considering reductive technologies for ground water remediation, it is important to understand the underlying principles that govern kinetics of zero-valent metal dechlorination. Studies involving the use of nanoscale metals (characteristic length <100nm) for chloro-organic degradation have increased reaction rates by 1-2 orders of magnitude with minimal intermediate formation. Typically, these metals are synthesized using modifications of the aqueous phase reduction of metal ions using sodium borohydride presented by Glavee and coworkers. The use of a bimetallic system increases the reactivity of the particle surface by incorporating a second metal that can typically act as a hydrogenation promotor.

  4. EFFECT OF DECHLORINATING BACTERIA ON THE LONGEVITY AND COMPOSITION OF PCE-CONTAINING NONAQUEOUS PHASE LIQUIDS UNDER EQUILIBRIUM DISSOLUTION CONDITIONS. (R826694C703)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. Optimization of ammonium acquisition and metabolism by potassium in rice (Oryza sativa L. cv. IR-72)pce_2046 23..34

    E-print Network

    Kronzucker, Herbert J.

    -words: cereals; channels; glutamine synthetase; influx, efflux; ion transport; nitrogen; phosphoenolpyruvate energy cost of futile NH4 + cycling at the plasma membrane. Activities of the key enzymes glutamine synthetase and phosphoenolpyruvate carboxylase (PEPC) were strongly stimulated by elevated K+ , mirroring

  6. STIMULATION OF REDUCTIVE DECHLORINATION OF TETRA- CHLOROETHENE (PCE) IN ANAEROBIC AQUIFER MICROCOSMS BY ADDITION OF SHORT-CHAIN ORGANIC ACIDS OR ALCOHOLS

    EPA Science Inventory

    The effect of the addition of common fermentation products on the dehalogenation of tetrachloroethene was studied in methanogenic slurries made with aquifer solids. Lactate, propionate, crotonate, butyrate, and ethanol stimulated dehalogenation activity, while acetate, methanol, ...

  7. Groundwater contamination and risk assessment of industrial complex in Busan Metropolitan City, Korea

    NASA Astrophysics Data System (ADS)

    Hamm, S.-Y.; Ryu, S. M.; Cheong, J.-Y.; Woo, Y.-J.

    2003-04-01

    In Korea, the potential of groundwater contamination in urban areas is increasing by industrial and domestic waste waters, leakage from oil storage tanks and sewage drains, leachate from municipal landfill sites and so on. Nowadays, chlorinated organic compounds such as trichloroethylene (TCE) and tetrachloroethylene (PCE), which are driving residential area as well as industrial area, are recognized as major hazardous contaminants. As well known, TCE is wisely used industrial activities such as degreasing, metal stripping, chemical manufacturing, pesticide production, coal gasification plants, creosote operation, and also used in automobile service centers, photo shops and laundries as cleaning solvent. Thus, groundwater protection in urban areas is important issue in Korea This study is to understand groundwater quality and contamination characteristics and to estimate risk assessment in Sasang industrial complex, Busan Metropolitan City. Busan Metropolitan City is located on southeastern coast of the Korean peninsula and is the second largest city in South Korea with a population of 3.8 millions. The geology of the study area is composed of andesite, andesitic tuff, biotite granite and alluvium (Kim et al., 1998). However, geology cannot be identified on the surface due to pavement and buildings. According to drill logs in the study area, the geologic section consists in landfill, fine sand, clay, gravelly clay, and biotite granite from the surface. Biotite granite appears 5.5- 6 m depth. Groundwater samples were collected at twenty sites in Sasang industrial complex. The groundwater samples are plotted on Piper's trilinear diagram, which indicates Ca-Cl2 type. The groundwater may be influenced by salt water because Sasang industrial complex is located near the mouse of Nakdong river that flows to the South Sea. The Ca-Cl2 water type may be partly influenced by anthropogenic contamination in the study area, since water type in granite area generally belongs Ca-HCO3 or Na-HCO3 types. TDS (107-14,500 /L), EC (225-25,500 ?S/cm), salinity (100-15,500 /kg), Na+ (13.39-2,866 /L) and Cl- (15.3-7,066 /L) concentrations are also higher than those of general groundwater. This fact indicates that groundwater in study area was polluted by saline water and/or anthropogenic sources. TCE, PCE, 1.1.1-trichloroethane (TCA) were analyzed by Busan Metropolitan City Institute of Health &Environment. PCE and TCA are not detected most of sites, while TCE is detected most of the sites and exceeds drinking water standard of Korea 0.03 /L. It is considered that TCE was derived from variety contamination sources such as car-washing centers, transportation companies, iron molding factories and waste treating companies. Risk assessment to human health and environmental resources by groundwater contamination was conducted. The RBCA Tool Kit for Chemical Releases can be used for the risk assessment at Tier 1 and Tier 2. The risk assessment determines risk-based concentration of constituents of concerns (COCs) that moves through groundwater, soil and air. It also evaluates carcinogenic risk and toxic effect when receptor exposures to the COCs. Tier 1 analysis determines risk-based screening levels (RBSLs) for one-site exposure. Tier 2 analysis evaluates RBSL and/or site-specific target levels (SSTLs) for both on-site and off-site receptor. RBSLs were calculated as 2.2E-2 /L for TCE and as 4.7E-3 /L for PCE at Tier 1 risk assessment. Average concentrations of TCE and PCE from measuring the groundwater samples were 0.15 mg/L and 0.016 mg/L, respectively. The actual measured values are higher than the RBSLs. Carcinogenic risk of TCE to animals was identified as B2 (inadequate or no human evidence but sufficient animal evidence). From this result, we will conduct the further detail risk assessment at Tier 2 level before conducting groundwater remediation. ACKNOWLEDGEMENT The authors wish to acknowledge the financial support of the Korea Science &Engineering Foundation (KOSEF) under the Basic Research Program (grant no: R02-2001-00249).

  8. THE TEMPERATURE DEPENDENCE OF THE EMISSION OF PERCHLORO- ETHYLENE FROM DRY CLEANED FABRICS

    EPA Science Inventory

    A study was conducted to evaluate the emission of perchloroethylene (tetrachloroethylene) from freshly dry cleaned fabrics using small environmental test chambers. The temperature dependence of the release of perchloroethylene was evaluated over a temperature range of 20 to 45°C....

  9. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...dry cleaning machine in a dry cleaning system including, but not...means any perchloroethylene dry cleaning facility that meets the conditions...perchloroethylene on the carbon. Coin-operated dry cleaning machine means a dry...

  10. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...dry cleaning machine in a dry cleaning system including, but not...means any perchloroethylene dry cleaning facility that meets the conditions...perchloroethylene on the carbon. Coin-operated dry cleaning machine means a dry...

  11. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...dry cleaning machine in a dry cleaning system including, but not...means any perchloroethylene dry cleaning facility that meets the conditions...perchloroethylene on the carbon. Coin-operated dry cleaning machine means a dry...

  12. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...dry cleaning machine in a dry cleaning system including, but not...means any perchloroethylene dry cleaning facility that meets the conditions...perchloroethylene on the carbon. Coin-operated dry cleaning machine means a dry...

  13. 76 FR 30545 - Approval of the Clean Air Act, Section 112(l), Authority for Hazardous Air Pollutants...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-26

    ...Perchloroethylene Air Emission Standards for Dry Cleaning Facilities: State of Maine Department of Environmental...Hazardous Air Pollutants for Perchloroethylene Dry Cleaning Facilities (``Dry Cleaning NESHAP''), as it applies to area...

  14. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...dry cleaning machine in a dry cleaning system including, but not...means any perchloroethylene dry cleaning facility that meets the conditions...perchloroethylene on the carbon. Coin-operated dry cleaning machine means a dry...

  15. 76 FR 30604 - Approval of the Clean Air Act, Section 112(l), Authority for Hazardous Air Pollutants...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-26

    ...Perchloroethylene Air Emission Standards for Dry Cleaning Facilities: State of Maine Department of Environmental...Hazardous Air Pollutants for Perchloroethylene Dry Cleaning Facilities (``Dry Cleaning NESHAP''), as it applies to area...

  16. Superfund record of decision (EPA Region 9): Camp Pendleton Marine Corps Base, Operable Unit 1, CA, December 7, 1995

    SciTech Connect

    1996-06-01

    Marine Corps Base (MCB) Camp Pendleton, California, is located between San Diego and Los Angeles. The purpose of this ROD is to set forth the remedial action for Site 9 groundwater, which is contaminated with the volatile organic compounds (VOCs) trichloroethene (TCE) and tetrachloroethene (PCE). In addition, this ROD sets forth the basis for the no remedial action decision for soil at Sites 9, 4, 4A, and 24 and for groundwater beneath Site 24. Soil at Sites 4, 4A and 9 and soil and groundwater at Site 24 were determined to be in a protective state; that is, the media at these sites pose no current or potential threat to human health or the environment.

  17. Superfund Record of Decision (EPA Region 1): Stamina Mills site, North Smithfield, RI. (First remedial action), September 1990. Final report

    SciTech Connect

    Not Available

    1990-09-28

    The five-acre Stamina Mills site is a former textile weaving and finishing facility in North Smithfield, Providence County, Rhode Island. A portion of the site is within the 100-year floodplain and wetland area of the Branch River. The manufacturing process used cleaning solvents, acids, bases and dyes for coloring, pesticides for moth proofing, and plasticizers to coat fabrics. Mill process wastes were placed in a landfill onsite. EPA initiated three removal actions from 1984 to 1990, including an extension of the municipal water supply to residents obtaining water from the affected aquifer; and treatment of two underground and one above-ground storage tanks, followed by offsite disposal. The Record of Decision (ROD) provides a final remedy and addresses both source control and management of contaminated ground water migration at the site. The primary contaminants of concern affecting the soil, debris, sediment, and ground water are VOCs including TCE and PCE; other organics including pesticides; and metals including chromium.

  18. In situ thermal desorption of soils impacted with chlorinated solvents

    SciTech Connect

    Vinegar, H.J.; Stegemeier, G.L.; Carl, F.G.; Stevenson, J.D.; Dudley, R.J.

    1999-07-01

    In situ thermal desorption (ISTD) has been demonstrated to remove high concentrations of chlorinated solvents such as PCE and TCE even from tight clay soils. ISTD applies heat and vacuum simultaneously to subsurface soils using thermal blankets for shallow contaminants (less than 2 ft depth) and thermal wells for deeper contamination. The ISTD process possesses a high removal efficiency because the narrow range of soil thermal conductivities provides excellent sweep efficiency and because its high operating temperature increases soil permeabilities and achieves complete displacement efficiency of contaminants in the gas phase. The first full scale commercial application of the ISTD well technology is described in detail for a site in Portland, Indiana, where silty clay soil was impacted with chlorinated solvents.

  19. Field experiences VOC and pesticide removal using GAC Suffolk County, New York

    SciTech Connect

    Harris, D.; Andreoli, A.; Baier, J.H.

    1992-01-01

    Over the past eight years, Granular Activated Carbon (GAC) systems have been installed for treatment of VOC and pesticides. Several have seen multiple carbon replacement; changes in water quality; and experienced a variety of operational difficulties. The following GAC systems will be discussed: Village of Greenport - one 20,000 lb. GAC operating from 1980 to present for removal of aldicarb and carbofuran; Southold - use of GAC in series for aldicarb, carbofuran and DCP; Dix Hills Water District - three 20,000 lb. units in parallel for removal of DCP; and Suffolk County Water Authority - 4 separate well fields treating aldicarb, DCP, TCA, TCE, PCE and others, with a variety of operating experiences. Operational problems encountered with each unit will also be discussed.

  20. Superfund Record of Decision (EPA Region 2): Higgins Farm, Franklin Township, Somerset County, NJ. (Second remedial action), September 1992. Final report

    SciTech Connect

    Not Available

    1992-09-30

    The 75-acre Higgins Farm site is a former cattle farm in Franklin Township, Somerset County, New Jersey. During the 1960's, municipal sludge and penicillin waste were used as fertilizers on Higgins Farm. The site also contains three holding tanks and drums containing material removed from previous remedial investigations. In 1986, the owner excavated 50 containers, including drums; however, during excavation activities, some of the containers were punctured and their contents spilled onto the ground. The ROD addresses the final action for ground water to limit future migration of contaminated ground water to offsite areas, as OU2. The primary contaminants of concern affecting the ground water are VOCs, including benzene, PCE, TCE, and xylene.

  1. Analysis and evaluation of VOC removal technologies demonstrated at Savannah River

    SciTech Connect

    Chesnut, D.A.; Wagoner, J.; Nitao, J.J.; Boyd, S.; Shaffer, R.J.; Kansa, E.J.; Buscheck, T.A.; Pruess, K.; Falta, R.W.

    1993-09-01

    Volatile Organic Compounds, or VOCs, are ubiquitous subsurface contaminants at industrial as well as DOE sites. At the Savannah River Plant, the principles VOCs contaminating the subsurface below A-Area and M-Area are Trichloroethylene (C{sub 2}HCl{sub 3}, or TCE) and Tetrachloroethylene (C{sub 2}Cl{sub 4}, or PCE). These compounds were used extensively as degreasing solvents from 1952 until 1979, and the waste solvent which did not evaporate (on the order of 2{times}10{sup 6} pounds) was discharged to a process sewer line leading to the M-Area Seepage Basin (Figure I.2). These compounds infiltrated into the soil and underlying sediments from leaks in the sewer line and elsewhere thereby contaminating the vadose zone between the surface and the water table as well as the aquifer.

  2. Operations Support of Phase 2 Integrated Demonstration In Situ Bioremediation. Volume 1, Final report: Final report text data in tabular form, Disk 1

    SciTech Connect

    Hazen, T.C.

    1993-09-01

    This project was designed to demonstrate in situ bioremediation of ground water and sediment contaminated with chlorinated solvents. Indigenous microorganisms were stimulated to degrade trichlorethylene (TCE), tetrachloroethylene (PCE) and their daughter products in situ by addition of nutrients to the contaminated aquifer and adjacent vadose zone. The principle carbon/energy source nutrient used in this demonstration was methane (natural gas). In situ biodegradation is a highly attractive technology for remediation because contaminants are destroyed, not simply moved to another location or immobilized, thus decreasing costs, risks, and time, while increasing efficiency, safety, and public and regulatory acceptability. This report describes the preliminary results of the demonstration and provides conclusions only for those measures that the Bioremediation Technical Support Group felt were so overwhelmingly convincing that they do not require further analyses. Though this report is necessarily superficial it does intend to provide a basis for further evaluating the technology and for practitioners to immediately apply some parts of the technology.

  3. Superfund Record of Decision (EPA Region 5): National Presto Industries, Eau Claire, WI. (First remedial action), August 1990

    SciTech Connect

    Not Available

    1990-08-01

    The 325-acre National Presto Industries site is a former munitions and metal-working facility in Eau Claire, Chippewa County, Wisconsin, adjacent to the town of Hallie. From 1942 until 1945, the site was government-owned, contractor-operated, and produced gunpowder and small arms. From 1945 to 1980, the site was owned by National Presto, which generated waste streams consisting of metals, oils, grease, and spent solvents. Also, beginning in 1951, artillery shell fuses, aircraft parts, and metal projectiles were produced by NPI under a military contract. The Record of Decision (ROD) provides for a permanent alternate water supply to address the principal threat posed by the ground water contamination at the site. The primary contaminants of concern affecting the ground water include VOCs such as PCE and TCE.

  4. Modeling GPR data to interpret porosity and DNAPL saturations for calibration of a 3-D multiphase flow simulation

    USGS Publications Warehouse

    Sneddon, Kristen W.; Powers, Michael H.; Johnson, Raymond H.; Poeter, Eileen P.

    2002-01-01

    Dense nonaqueous phase liquids (DNAPLs) are a pervasive and persistent category of groundwater contamination. In an effort to better understand their unique subsurface behavior, a controlled and carefully monitored injection of PCE (perchloroethylene), a typical DNAPL, was performed in conjunction with the University of Waterloo at Canadian Forces Base Borden in 1991. Of the various geophysical methods used to monitor the migration of injected PCE, the U.S. Geological Survey collected 500-MHz ground penetrating radar (GPR) data. These data are used in determining calibration parameters for a multiphase flow simulation. GPR data were acquired over time on a fixed two-dimensional surficial grid as the DNAPL was injected into the subsurface. Emphasis is on the method of determining DNAPL saturation values from this time-lapse GPR data set. Interactive full-waveform GPR modeling of regularized field traces resolves relative dielectric permittivity versus depth profiles for pre-injection and later-time data. Modeled values are end members in recursive calculations of the Bruggeman-Hanai-Sen (BHS) mixing formula, yielding interpreted pre-injection porosity and post-injection DNAPL saturation values. The resulting interpreted physical properties of porosity and DNAPL saturation of the Borden test cell, defined on a grid spacing of 50 cm with 1-cm depth resolution, are used as observations for calibration of a 3-D multiphase flow simulation. Calculated values of DNAPL saturation in the subsurface at 14 and 22 hours after the start of injection, from both the GPR and the multiphase flow modeling, are interpolated volumetrically and presented for visual comparison.

  5. Monitoring Abundance and Expression of “Dehalococcoides” Species Chloroethene-Reductive Dehalogenases in a Tetrachloroethene-Dechlorinating Flow Column? †

    PubMed Central

    Behrens, Sebastian; Azizian, Mohammad F.; McMurdie, Paul J.; Sabalowsky, Andrew; Dolan, Mark E.; Semprini, Lew; Spormann, Alfred M.

    2008-01-01

    We investigated the distribution and activity of chloroethene-degrading microorganisms and associated functional genes during reductive dehalogenation of tetrachloroethene to ethene in a laboratory continuous-flow column. Using real-time PCR, we quantified “Dehalococcoides” species 16S rRNA and chloroethene-reductive dehalogenase (RDase) genes (pceA, tceA, vcrA, and bvcA) in nucleic acid extracts from different sections of the column. Dehalococcoides 16S rRNA gene copies were highest at the inflow port [(3.6 ± 0.6) × 106 (mean ± standard deviation) per gram soil] where the electron donor and acceptor were introduced into the column. The highest transcript numbers for tceA, vcrA, and bvcA were detected 5 to 10 cm from the column inflow. bvcA was the most highly expressed of all RDase genes and the only vinyl chloride reductase-encoding transcript detectable close to the column outflow. Interestingly, no expression of pceA was detected in the column, despite the presence of the genes in the microbial community throughout the column. By comparing the 16S rRNA gene copy numbers to the sum of all four RDase genes, we found that 50% of the Dehalococcoides population in the first part of the column did not contain either one of the known chloroethene RDase genes. Analysis of 16S rRNA gene clone libraries from both ends of the flow column revealed a microbial community dominated by members of Firmicutes and Actinobacteria. Higher clone sequence diversity was observed near the column outflow. The results presented have implications for our understanding of the ecophysiology of reductively dehalogenating Dehalococcoides spp. and their role in bioremediation of chloroethenes. PMID:18676701

  6. Anthropogenic Organic Compounds in Source and Finished Water from Community Water System Wells in Western and Central Connecticut, 2002-2004

    USGS Publications Warehouse

    Trombley, Thoams J.; Brown, Craig J.; Delzer, Gregory C.

    2007-01-01

    A water-quality assessment by the U.S. Geological Survey (USGS) determined the occurrence of anthropogenic (manmade) organic compounds (AOCs) in water from 15 community water system (CWS) wells and associated finished drinking water. The study, which focused on water from the unconfined glacial stratified aquifer in western and central Connecticut, was conducted as part of the USGS National Water-Quality Assessment Program (NAWQA) Source Water-Quality Assessment (SWQA) project and included analysis of water samples for 88 volatile organic compounds (VOCs), 120 pesticides, and 50 other anthropogenic organic compounds (OAOCs). During Phase I of the study, 25 AOCs were detected (12 VOCs, 10 pesticides, and 3 OAOCs) in source-water samples collected from 15 CWS wells sampled once from October 2002 to May 2003. Although concentrations generally were low (less than 1 microgram per liter), four compounds were detected at higher concentrations in ground water from four wells. The most frequently occurring AOCs were detected in more than half of the samples and included chloroform (87 percent), methyl tert-butyl ether (MTBE, 80 percent), 1,1,1-trichloroethane (67 percent), atrazine (60 percent), deethylatrazine (60 percent), perchloroethene (PCE, 53 percent), and simazine (53 percent). Trichloroethene (TCE) was detected in 47 percent of samples. Samples generally contained a mixture of compounds ranging from 2 to 19 detected compounds, with an average of 8 detected compounds per sample. During Phase II of the study, 42 AOCs were detected in source-water samples collected from 10 resampled CWS wells or their associated finished water. Trihalomethanes accounted for most of the VOCs detections with all concentrations less than 1 microgram per liter. Chloroform, the most frequently detected VOC, was found in all source-water and all finished-water samples. As with the Phase I samples, other frequently detected VOCs included MTBE, and the solvents 1,1,1-trichloroethane, PCE, and TCE. Triazine herbicides and their degradation products accounted for most of the detected pesticides.

  7. Comparison of diffusion- and pumped-sampling methods to monitor volatile organic compounds in ground water, Massachusetts Military Reservation, Cape Cod, Massachusetts, July 1999-December 2002

    USGS Publications Warehouse

    Archfield, Stacey A.; LeBlanc, Denis R.

    2005-01-01

    To evaluate diffusion sampling as an alternative method to monitor volatile organic compound (VOC) concentrations in ground water, concentrations in samples collected by traditional pumped-sampling methods were compared to concentrations in samples collected by diffusion-sampling methods for 89 monitoring wells at or near the Massachusetts Military Reservation, Cape Cod. Samples were analyzed for 36 VOCs. There was no substantial difference between the utility of diffusion and pumped samples to detect the presence or absence of a VOC. In wells where VOCs were detected, diffusion-sample concentrations of tetrachloroethene (PCE) and trichloroethene (TCE) were significantly lower than pumped-sample concentrations. Because PCE and TCE concentrations detected in the wells dominated the calculation of many of the total VOC concentrations, when VOC concentrations were summed and compared by sampling method, visual inspection also showed a downward concentration bias in the diffusion-sample concentration. The degree to which pumped- and diffusion-sample concentrations agreed was not a result of variability inherent within the sampling methods or the diffusion process itself. A comparison of the degree of agreement in the results from the two methods to 13 quantifiable characteristics external to the sampling methods offered only well-screen length as being related to the degree of agreement between the methods; however, there is also evidence to indicate that the flushing rate of water through the well screen affected the agreement between the sampling methods. Despite poor agreement between the concentrations obtained by the two methods at some wells, the degree to which the concentrations agree at a given well is repeatable. A one-time, well-bywell comparison between diffusion- and pumped-sampling methods could determine which wells are good candidates for the use of diffusion samplers. For wells with good method agreement, the diffusion-sampling method is a time-saving and cost-effective alternative to pumped-sampling methods in a long-term monitoring program, such as at the Massachusetts Military Reservation.

  8. Relation of organic contaminant equilibrium sorption and kinetic uptake in plants

    USGS Publications Warehouse

    Li, H.; Sheng, G.; Chiou, C.T.; Xu, O.

    2005-01-01

    Plant uptake is one of the environmental processes that influence contaminant fate. Understanding the magnitude and rate of plant uptake is critical to assessing potential crop contamination and the development of phytoremediation technologies. We determined (1) the partition-dominated equilibrium sorption of lindane (LDN) and hexachlorobenzene (HCB) by roots and shoots of wheat seedlings, (2) the kinetic uptake of LDN and HCB by roots and shoots of wheat seedlings, (3) the kinetic uptake of HCB, tetrachloroethylene (PCE), and trichloroethylene (TCE) by roots and shoots of ryegrass seedlings, and (4) the lipid, carbohydrate, and water contents of the plants. Although the determined sorption and the plant composition together suggest the predominant role of plant lipids for the sorption of LDN and HCB, the predicted partition with lipids of LDN and HCB using the octanol-water partition coefficients is notably lower than the measured sorption, due presumably to underestimation of the plant lipid contents and to the fact that octanol is less effective as a partition medium than plant lipids. The equilibrium sorption or the estimated partition can be viewed as the kinetic uptake limits. The uptakes of LDN, PCE, and TCE from water at fixed concentrations increased with exposure time in approach to steady states. The uptake of HCB did not reach a plateau within the tested time because of its exceptionally high partition coefficient. In all of the cases, the observed uptakes were lower than their respective limits, due presumably to contaminant dissipation in and limited water transpiration by the plants. ?? 2005 American Chemical Society.

  9. An Overview of In-Stu Treatability Studies at Marshall Space Flight Center, Huntsville, Alabama

    NASA Technical Reports Server (NTRS)

    McElroy, Bill; Keith, Amy; Glasgow, J. K.; Dasappa, Srini; McCaleb, Rebecca (Technical Monitor)

    2001-01-01

    Marshall Space Flight Center (MSFC) is located in Huntsville, Alabama (north-central Alabama), on approximately 1,840 acres near the center of the U.S. Army's Redstone Arsenal (RSA). MSFC is the National Aeronautics and Space Administration's (NASA's) principal propulsion development center. Its scientists, engineers, and support personnel play a major role in the National Space Transportation System by managing space shuttle mission activities, including the microgravity laboratory. In addition, MSFC will be a significant contributor to several of NASA's future programs, including the Reusable Launch Vehicle (X-33), International Space Station, and Advanced X-ray Astrophysics Facility, as well as research on a variety of space science applications. MSFC has been used to develop, test and manufacture space vehicles and components since 1960, when civilian rocketry and missile activities were transferred from RSA to MSFC. In 1994, MSFC was placed on the National Priority List for the management of hazardous waste sites, under the requirements of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). One requirement of the CERCLA program is to evaluate the nature and extent of environmental contamination resulting from identified CERCLA sites, assess the public health and environmental risks associated with the identified contamination, and identify potential remedial actions. A CERCLA remedial investigation (RI) for the groundwater system has identified at least five major plumes of chlorinated volatile organic compounds (CVOCs) in the groundwater beneath the facility. These plumes are believed to be the result of former management practices at 14 main facility locations (termed "source areas") where CVOCs were released to the subsurface. Trichloroethene (TCE) is the predominant CVOC and is common to all the plumes. Perchloroethene (PCE) also exists in two of the plumes. In addition to TCE and PCE, carbon tetrachloride and 1,1,2,2-tetrachloroethane are contained in one of the plumes. The CVOCs are believed to exist as dense non-aqueous phase liquids (DNAPLs) beneath many of the source areas.

  10. Effect of Various Enhanced-Solubilization Agents on Multi-Component Immiscible Liquid Dissolution and Mass Flux in Homogeneous Porous Media

    NASA Astrophysics Data System (ADS)

    Tick, G. R.; Slavic, D.

    2010-12-01

    Complex multi-component immiscible liquid mixtures can significantly limit the effectiveness of groundwater remediation. The use of enhanced-flushing technologies has emerged as a promising technique for the remediation of sites contaminated with immiscible liquids. An important aspect for the effective remediation of these sites depends on the physical heterogeneity of the subsurface, the related distribution of immiscible liquid present within porous media, and the composition of the immiscible liquid mixture. A series of column experiments was conducted to quantify the effectiveness of four different flushing agents on the removal of a uniformly distributed multi-component immiscible liquid consisting of equal mole fractions of tetrachloroethene (PCE), trichloroethene (TCE), and cis-1,2-dichloroethene (DCE) in homogeneous quartz sand. The solubilization agents investigated included: two complexing sugars, hydroxypropyl-?-cyclodextrin (HPCD) and methyl-?-cyclodextrin (MCD); one surfactant, sodium dodecyl sulfate (SDS); and one cosolvent, ethanol (ETOH). The effectiveness of the flushing agents was evaluated by comparing elution profiles, flushing efficiencies, mass flux behavior, and dissolution ideality (i.e. Raoult’s law prediction) of each component. The results of these experiments indicate that the addition of a chemical flushing agent greatly reduces the time needed to remove each component compared to flushing with water alone (i.e. pump and treat). Although the stronger solubilization-power agents (i.e. SDS and ETOH) showed quicker removal in general, each solubilization agent exhibited unique removal limitations based upon different removal efficiency analyses. For instance, TCE and DCE exhibited relatively ideal dissolution while PCE showed significant nonideal dissolution behavior during flushing with MCD. These findings suggest that the selection of a particular flushing agent should be evaluated carefully prior to remediation as the mass flux and removal behavior of each component will significantly vary depending on the flushing agent itself.

  11. Selection of treatment technologies for vapor streams contaminated with chlorinated solvents

    SciTech Connect

    Georgius, C.R.; Hagarty, E.P.

    1995-12-31

    At a dry cleaning facility on the Fort Myer military installation in Virginia, soils became contaminated with perchloroethylene (PCE) as a result of leaking storage containers and improper housekeeping procedures. A soil vapor extraction system was installed to remediate vadose zone soils. The systems included carbon adsorption for treatment of the contaminated vapor stream removed from the soils. As a result of high removal rates, and other operational problems, the carbon use greatly exceeded original estimates. An evaluation of the system was conducted which included an assessment of the most appropriate treatment method for the vapor stream. The evaluation considered several emerging technologies including catalytic oxidation and thermal treatment, as well as continuation of the existing carbon adsorption. Several operational improvements were recommended which make this a useful case study for the future designs of this evolving technology. Technology selection depends on site specific conditions, required remedial time frame, cost effectiveness, and regulatory constraints. The objective of this paper is to describe the evaluation of the soil vapor extraction system including the alternative offgas treatment technologies. The basis for recommendation of the selected alternative is also presented.

  12. FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS

    SciTech Connect

    John F. Schabron; Joseph F. Rovani Jr.; Theresa M. Bomstad

    2002-06-01

    Western Research Institute (WRI) initiated exploratory work towards the development of new field screening methodology and a test kit to measure halogenated volatile organic compounds (VOCs) in the field. Heated diode and corona discharge sensors are commonly used to detect leaks of refrigerants from air conditioners, freezers, and refrigerators. They are both selective to the presence of carbon-halogen bonds. Commercially available heated diode and corona discharge leak detectors were procured and evaluated for halogenated VOC response. The units were modified to provide a digital readout of signal related to VOC concentration. Sensor response was evaluated with carbon tetrachloride and tetrachloroethylene (perchloroethylene, PCE), which represent halogenated VOCs with and without double bonds. The response characteristics were determined for the VOCs directly in headspace in Tedlar bag containers. Quantitation limits in air were estimated. Potential interferences from volatile hydrocarbons, such as toluene and heptane, were evaluated. The effect of humidity was studied also. The performance of the new devices was evaluated in the laboratory by spiking soil samples and monitoring headspace for halogenated VOCs. A draft concept of the steps for a new analytical method was outlined. The results of the first year effort show that both devices show potential utility for future analytical method development work towards the goal of developing a portable test kit for screening halogenated VOCs in the field.

  13. 'Effects of Elevated Temperature on Dehalococcoides Dechlorination Performance and DNA and RNA Biomarker Abundance

    SciTech Connect

    Fletcher, Kelly E; Costanza, Jed; Cruz-Garcia, Claribel; Ramaswamy, Nivedhya; Pennell, Kurt; Loeffler, Frank E

    2011-01-01

    Coupling thermal treatment with microbial reductive dechlorination is a promising remedy for tetrachloroethene (PCE) and trichloroethene (TCE) contaminated source zones. Laboratory experiments evaluated Dehalococcoides (Dhc) dechlorination performance, viability, and biomarker gene (DNA) and transcript (mRNA) abundances during exposure to elevated temperatures. The PCE-dechlorinating consortia BDI and OW produced ethene when incubated at temperatures of 30 C, but vinyl chloride (VC) accumulated when cultures were incubated at 35 or 40 C. Cultures incubated at 40 C for less than 49 days resumed VC dechlorination following cooling; however, incubation at 45 C resulted in complete loss of dechlorination activity. Dhc 16S rRNA, bvcA, and vcrA gene abundances in cultures showing complete dechlorination to ethene at 30 C exceeded those measured in cultures incubated at higher temperatures, consistent with observed dechlorination activities. Conversely, biomarker gene transcript abundances per cell in cultures incubated at 35 and 40 C were generally at least one order-of-magnitude greater than those measured in ethene-producing cultures incubated at 30 C. Even in cultures accumulating VC, transcription of the vcrA gene, which is implicated in VC-to-ethene dechlorination, was up-regulated. Temperature stress caused the up-regulation of Dhc reductive dehalogenase gene expression indicating that Dhc gene expression measurements should be interpreted cautiously as Dhc biomarker gene transcript abundances may not correlate with dechlorination activity.

  14. Mechanisms, Chemistry, and Kinetics of Anaerobic Biodegradation of cis-Dichloroethene and Vinyl Chloride

    SciTech Connect

    McCarty, P.L.; Spormann, A.M.

    2000-12-01

    Anaerobic biological processes can result in PCE and TCE destruction through conversion to cis-dichloroethene (cDCE) then to vinyl chloride (VC), and finally to ethene. Here, the chlorinated aliphatic hydrocarbons (CAHs) serve as electron acceptors in energy metabolism, requiring electron donors such as hydrogen from an external source. The purpose of this study was to learn more about the biochemistry of cDCE and VC conversion to ethene, to better understand the requirements for electron donors, and to determine factors affecting the rates of CAH degradation and organism growth. The biochemistry of reductive dehalogenation of VC was studied with an anaerobic mixed culture enriched on VC. In other studies on electron donor needs for dehalogenation of cDCE and VC, competition for hydrogen was found to occur between the dehalogenators and other microorganisms such as methanogens and homoacetogens in a benzoate-acclimated dehalogenating methanogenic mixed culture. Factors affecting the relative rates of destruction of the solvents and their intermediate products were evaluated. Studies using a mixed PCE-dehalogenating culture as well as the VC enrichment for biochemical studies suggested that the same species was involved in both cDCE and VC dechlorination, and that cDCE and VC competitively inhibited each other's dechlorination rate.

  15. D-area oil seepage basin bioventing optimization test plan

    SciTech Connect

    Berry, C.J.; Radway, J.C.; Alman, D.; Hazen, T.C.

    1998-12-31

    The D Area Oil Seepage Basin (DOSB) was used from 1952 to 1975 for disposal of petroleum-based products (waste oils), general office and cafeteria waste, and apparently some solvents [trichloroethylene (TCE)/tetrachloroethylene (PCE)]. Numerous analytical results have indicated the presence of TCE and its degradation product vinyl chloride in groundwater in and around the unit, and of petroleum hydrocarbons in soils within the unit. The DOSB is slated for additional assessment and perhaps for environmental remediation. In situ bioremediation represents a technology of demonstrated effectiveness in the reclamation of sites contaminated with petroleum hydrocarbons and chlorinated solvents, and has been retained as an alternative for the cleanup of the DOSB. The Savannah River Site is therefore proposing to conduct a field treatability study designed to demonstrate and optimize the effectiveness of in situ microbiological biodegradative processes at the DOSB. The introduction of air and gaseous nutrients via two horizontal injection wells (bioventing) is expected to enhance biodegradation rates of petroleum components and stimulate microbial degradation of chlorinated solvents. The data gathered in this test will allow a determination of the biodegradation rates of contaminants of concern in the soil and groundwater, allow an evaluation of the feasibility of in situ bioremediation of soil and groundwater at the DOSB, and provide data necessary for the functional design criteria for the final remediation system.

  16. A transition in the spatially integrated reaction rate of bimolecular reaction-diffusion systems

    NASA Astrophysics Data System (ADS)

    Arshadi, Masoud; Rajaram, Harihar

    2015-09-01

    Numerical simulations of diffusion with bimolecular reaction demonstrate a transition in the spatially integrated reaction rate—increasing with time initially, and transitioning to a decrease with time. In previous work, this reaction-diffusion problem has been analyzed as a Stefan problem involving a distinct moving boundary (reaction front), leading to predictions that front motion scales as ?t, and correspondingly the spatially integrated reaction rate decreases as the square root of time 1/?t. We present a general nondimensionalization of the problem and a perturbation analysis to show that there is an early time regime where the spatially integrated reaction rate scales as ?t rather than 1/?t. The duration of this early time regime (where the spatially integrated reaction rate is kinetically rather than diffusion controlled) is shown to depend on the kinetic rate parameters, diffusion coefficients, and initial concentrations of the two species. Numerical simulation results confirm the theoretical estimates of the transition time. We present illustrative calculations in the context of in situ chemical oxidation for remediation of fractured rock systems where contaminants are largely dissolved in the rock matrix. We consider different contaminants of concern (COCs), including TCE, PCE, MTBE, and RDX. While the early time regime is very short lived for TCE, it can persist over months to years for MTBE and RDX, due to slow oxidation kinetics.

  17. Superfund Record of Decision (EPA Region 10): American Lake Gardens (McCord AFB - Area D), Pierce County, WA. (First remedial action), September 1991. Final report

    SciTech Connect

    Not Available

    1991-09-19

    The American Lake Gardens (McChord AFB-Area D) site is an active U.S. Air Force base located at McChord Air Force Base, Pierce County, Washington. The site consists of two areas, Area D and American Lake Garden Tract (ALGT). From the mid-1940's to the present, no known industrial activities have occurred in the ALGT area; however, seven waste disposal sites have operated within the Area D portion of the site. Concurrent with DOD investigations, EPA discovered TCE in ground water monitoring wells installed at the ALGT, and in 1984, concluded that waste disposal sites in Area D were the likely source of ground water contamination. The ROD addresses remediation of the contaminated onsite and offsite ground water plume, as a final remedy. The primary contaminants of concern affecting the ground water are VOCs including benzene, PCE, TCE, toluene, and xylenes; other organics; and metals including arsenic, chromium, and lead. The selected remedial action for the site is included.

  18. Induced Polarization with Electromagnetic Coupling: 3D Spectral Imaging Theory, EMSP Project No. 73836

    SciTech Connect

    Morgan, F. Dale; Sogade, John

    2004-12-14

    This project was designed as a broad foundational study of spectral induced polarization (SIP) for characterization of contaminated sites. It encompassed laboratory studies of the effects of chemistry on induced polarization, development of 3D forward modeling and inversion codes, and investigations of inductive and capacitive coupling problems. In the laboratory part of the project a physico-chemical model developed in this project was used to invert laboratory IP spectra for the grain size and the effective grain size distribution of the sedimentary rocks as well as the formation factor, porosity, specific surface area, and the apparent fractal dimension. Furthermore, it was established that the IP response changed with the solution chemistry, the concentration of a given solution chemistry, valence of the constituent ions, and ionic radius. In the field part of the project, a 3D complex forward and inverse model was developed. It was used to process data acquired at two frequencies (1/16 Hz and 1/ 4Hz) in a cross-borehole configuration at the A-14 outfall area of the Savannah River Site (SRS) during March 2003 and June 2004. The chosen SRS site was contaminated with Tetrachloroethylene (TCE) and Trichloroethylene (PCE) that were disposed in this area for several decades till the 1980s. The imaginary conductivity produced from the inverted 2003 data correlated very well with the log10 (PCE) concentration derived from point sampling at 1 ft spacing in five ground-truth boreholes drilled after the data acquisition. The equivalent result for the 2004 data revealed that there were significant contaminant movements during the period March 2003 and June 2004, probably related to ground-truth activities and nearby remediation activities. Therefore SIP was successfully used to develop conceptual models of volume distributions of PCE/TCE contamination. In addition, the project developed non-polarizing electrodes that can be deployed in boreholes for years. A total of 28 of these electrodes were deployed at the SRS site in September of 2002. The project found that (1) currently available field instrumentation need to be faster by an order of magnitude for full SIP to be engaged for broadband characterization in the field, (2) some aspects of the capacitive coupling problem in borehole geometries can be solved by use of a high impedance receiver, (3) a careful investigation of ways to adequately compare inversion results to ground-truth data is warranted, (4) more laboratory studies should be directed to understand the influence of micro-organisms and long residence time of contaminants (aging) on spectral IP properties.

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

    SciTech Connect

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

    2012-09-20

    Soil vapor extraction (SVE) and air injection well testing was performed at the Dynamic Underground Stripping (DUS) site located near the M-Area Settling Basin (referred to as DUS II in this report). The objective of this testing was to determine the effectiveness of continued operation of these systems. Steam injection ended on September 19, 2009 and since this time the extraction operations have utilized residual heat that is present in the subsurface. The well testing campaign began on June 5, 2012 and was completed on June 25, 2012. Thirty-two (32) SVE wells were purged for 24 hours or longer using the active soil vapor extraction (ASVE) system at the DUS II site. During each test five or more soil gas samples were collected from each well and analyzed for target volatile organic compounds (VOCs). The DUS II site is divided into four parcels (see Figure 1) and soil gas sample results show the majority of residual VOC contamination remains in Parcel 1 with lesser amounts in the other three parcels. Several VOCs, including tetrachloroethylene (PCE) and trichloroethylene (TCE), were detected. PCE was the major VOC with lesser amounts of TCE. Most soil gas concentrations of PCE ranged from 0 to 60 ppmv with one well (VEW-22A) as high as 200 ppmv. Air sparging (AS) generally involves the injection of air into the aquifer through either vertical or horizontal wells. AS is coupled with SVE systems when contaminant recovery is necessary. While traditional air sparging (AS) is not a primary component of the DUS process, following the cessation of steam injection, eight (8) of the sixty-three (63) steam injection wells were used to inject air. These wells were previously used for hydrous pyrolysis oxidation (HPO) as part of the DUS process. Air sparging is different from the HPO operations in that the air was injected at a higher rate (20 to 50 scfm) versus HPO (1 to 2 scfm). . At the DUS II site the air injection wells were tested to determine if air sparging affected VOC soil gas concentrations during ASVE. Five (5) SVE wells that were located closest to the air injection wells were used as monitoring points during the air sparging tests. The air sparging tests lasted 48 hours. Soil gas sample results indicate that sparging did not affect VOC concentrations in four of the five sparging wells, while results from one test did show an increase in soil gas concentrations.

  20. Relative contribution of DNAPL dissolution and matrix diffusion to the long-term persistence of chlorinated solvent source zones

    NASA Astrophysics Data System (ADS)

    Seyedabbasi, Mir Ahmad; Newell, Charles J.; Adamson, David T.; Sale, Thomas C.

    2012-06-01

    The relative contribution of dense non-aqueous phase liquid (DNAPL) dissolution versus matrix diffusion processes to the longevity of chlorinated source zones was investigated. Matrix diffusion is being increasingly recognized as an important non-DNAPL component of source behavior over time, and understanding the persistence of contaminants that have diffused into lower permeability units can impact remedial decision-making. In this study, a hypothetical DNAPL source zone architecture consisting of several different sized pools and fingers originally developed by Anderson et al. (1992) was adapted to include defined low permeability layers. A coupled dissolution-diffusion model was developed to allow diffusion into these layers while in contact with DNAPL, followed by diffusion out of these same layers after complete DNAPL dissolution. This exercise was performed for releases of equivalent masses (675 kg) of three different compounds, including chlorinated solvents with solubilities ranging from low (tetrachloroethene (PCE)), moderate (trichloroethene (TCE)) to high (dichloromethane (DCM)). The results of this simple modeling exercise demonstrate that matrix diffusion can be a critical component of source zone longevity and may represent a longer-term contributor to source longevity (i.e., longer time maintaining concentrations above MCLs) than DNAPL dissolution alone at many sites. For the hypothetical TCE release, the simulation indicated that dissolution of DNAPL would take approximately 38 years, while the back diffusion from low permeability zones could maintain the source for an additional 83 years. This effect was even more dramatic for the higher solubility DCM (97% of longevity due to matrix diffusion), while the lower solubility PCE showed a more equal contribution from DNAPL dissolution vs. matrix diffusion. Several methods were used to describe the resulting source attenuation curves, including a first-order decay model which showed that half-life of mass discharge from the matrix-diffusion dominated phase is in the range of 13 to 29 years for TCE. Because the mass discharge rate shifts significantly over time once DNAPL dissolution is complete, a Power-Law model was shown to be useful, especially at later stages when matrix diffusion dominates. An assessment of mass distribution showed that while relatively small percentages of the initial source mass diffused into the low permeability compartment, this mass was sufficient to sustain concentrations above drinking water standards for decades. These data show that relatively typical conditions (e.g., 50-year-old release, moderate to high solubility contaminant) are consistent with late stage sources, where mass in low permeability matrices serves as the primary source, and fit the conceptual model that mass in low permeability zones is important when evaluating source longevity.

  1. Relative contribution of DNAPL dissolution and matrix diffusion to the long-term persistence of chlorinated solvent source zones.

    PubMed

    Seyedabbasi, Mir Ahmad; Newell, Charles J; Adamson, David T; Sale, Thomas C

    2012-06-01

    The relative contribution of dense non-aqueous phase liquid (DNAPL) dissolution versus matrix diffusion processes to the longevity of chlorinated source zones was investigated. Matrix diffusion is being increasingly recognized as an important non-DNAPL component of source behavior over time, and understanding the persistence of contaminants that have diffused into lower permeability units can impact remedial decision-making. In this study, a hypothetical DNAPL source zone architecture consisting of several different sized pools and fingers originally developed by Anderson et al. (1992) was adapted to include defined low permeability layers. A coupled dissolution-diffusion model was developed to allow diffusion into these layers while in contact with DNAPL, followed by diffusion out of these same layers after complete DNAPL dissolution. This exercise was performed for releases of equivalent masses (675 kg) of three different compounds, including chlorinated solvents with solubilities ranging from low (tetrachloroethene (PCE)), moderate (trichloroethene (TCE)) to high (dichloromethane (DCM)). The results of this simple modeling exercise demonstrate that matrix diffusion can be a critical component of source zone longevity and may represent a longer-term contributor to source longevity (i.e., longer time maintaining concentrations above MCLs) than DNAPL dissolution alone at many sites. For the hypothetical TCE release, the simulation indicated that dissolution of DNAPL would take approximately 38 years, while the back diffusion from low permeability zones could maintain the source for an additional 83 years. This effect was even more dramatic for the higher solubility DCM (97% of longevity due to matrix diffusion), while the lower solubility PCE showed a more equal contribution from DNAPL dissolution vs. matrix diffusion. Several methods were used to describe the resulting source attenuation curves, including a first-order decay model which showed that half-life of mass discharge from the matrix-diffusion dominated phase is in the range of 13 to 29 years for TCE. Because the mass discharge rate shifts significantly over time once DNAPL dissolution is complete, a Power-Law model was shown to be useful, especially at later stages when matrix diffusion dominates. An assessment of mass distribution showed that while relatively small percentages of the initial source mass diffused into the low permeability compartment, this mass was sufficient to sustain concentrations above drinking water standards for decades. These data show that relatively typical conditions (e.g., 50-year-old release, moderate to high solubility contaminant) are consistent with late stage sources, where mass in low permeability matrices serves as the primary source, and fit the conceptual model that mass in low permeability zones is important when evaluating source longevity. PMID:22591740

  2. Cracking of Clay Due to Contact with Waste Chlorinated Solvents

    NASA Astrophysics Data System (ADS)

    Otero, M.; Ayral, D.; Shipan, J.; Goltz, M. N.; Huang, J.; Demond, A. H.

    2012-12-01

    Clays are known to crack upon desiccation. Desiccation cracks of up to 3 cm wide have been reported in natural soils. This raises the question if a similar behavior is seen when a dense non-aqueous phase liquids (DNAPL) waste is in contact with clay. The contact with organic liquids causes the clay structure to shrink, leading to the formation of cracks. Moreover, DNAPL waste not only contains the organic liquid solvent but also includes surface-active solutes or surfactants. Such solutes can enhance the interaction of the organic solvents with the clay. This research will assess whether or not contact with chlorinated organic waste causes cracking. In order to evaluate the possibility of cracking in the clay, microcosms have been constructed that mimic aquifer systems, consisting of a saturated layer of sand, a saturated layer of bentonite clay and a 2.5 cm layer of either pure chlorinated solvents or DNAPL waste. The onset of cracking for the microcosm with tetrachloroethylene (PCE) waste as the DNAPL layer occurred after ten days of contact. Similarly, at eight days, cracks were observed in a microcosm containing trichloroethylene (TCE) waste . Forty-four days later, the length and number of cracks have grown considerably; with a total crack length of 50 cm on a surface of 80 cm2 in the microcosm containing PCE waste. On the other hand it took approximately 161 days for the clay layer in the microcosm containing pure PCE to crack. To quantity the degree of cracking, crack maps were developed using the image software, Image J. Characteristics like crack length, crack aperture, and the percentage of total length for a range of apertures were calculated using this software. For example, for the PCE waste microcosm, it was calculated that 3.7% of the crack length had an aperture of 100-300 microns, 15.1% of the crack length had an aperture of 300-500 microns, 29.7% of the crack length had an aperture of 500-700 microns, 40.1% of the crack length had an aperture of 700-900 microns, 6.3% had an aperture of 900-1,100 microns and 5.1% had an aperture of over 1,100 microns. These data suggest that aquitards in the field might crack when in contact with the DNAPL waste. Moreover, it is apparent that the waste contains solutes that accelerate the cracking of the clay layer. Thus, models examining the impact of storage in low permeability layers need to consider the possible impact of cracking.

  3. GE/NOMADICS IN-WELL MONITORING SYSTEM FOR VERTICAL PROFILING OF DNAPL CONTAMINANTS

    SciTech Connect

    Ronald E. Shaffer; Radislav Potyralio; Joseph Salvo; Timothy Sivavec; Lloyd Salsman

    2003-04-01

    This report describes the Phase I effort to develop an Automated In Well Monitoring System (AIMS) for in situ detection of chlorinated volatile organic compounds such as trichloroethylene (TCE) and tetrachloroethylene (PCE) in groundwater. AIMS is composed of 3 primary components: (a) sensor probe, (b) instrument delivery system, and (c) communication/recharging station. The sensor probe utilizes an array of thickness shear mode (TSM) sensors coated with chemically-sensitive polymer films provides a low-cost, highly sensitive microsensor platform for detection and quantification. The instrument delivery system is used to position the sensor probe in 2 inch or larger groundwater monitoring wells. A communication/recharging station provides wireless battery recharging and communication to enable a fully automated system. A calibration curve for TCE in water was built using data collected in the laboratory. The detection limit of the sensor probe was 6.7 ppb ({micro}g/L) for TCE in water. A preliminary field test was conducted at a GE remediation location and a pilot field test was performed at the DOE Savannah River Site (SRS). The AIMS system was demonstrated in an uncontaminated (i.e., ''clean'') 2-inch well and in a 4-inch well containing 163.5 ppb of TCE. Repeat measurements at the two wells indicated excellent day-to-day reproducibility. Significant differences in the sensor responses were noted between the two types of wells but they did not closely match the laboratory calibration data. The robustness of the system presented numerous challenges for field work and limited the scope of the SRS pilot field test. However, the unique combination of trace detection (detection limits near the MCL, minimum concentration level) and size (operations in 2-inch or larger groundwater wells) is demonstration of the promise of this technology for long-term monitoring (LTM) applications or rapid site characterization. Using the lessons learned from the pilot field test, a number of design changes are proposed to increase the robustness of the system for extended field studies and commercialization.

  4. Case Studies of Transcranial Electrical Motor Evoked Potentials (TCeMEP) on Patients with Charcot-Marie-Tooth Disease during Posterior Spinal Instrumentation and Fusion.

    PubMed

    Schmidt, Robert; Mani, Prasitha; Weber, Deborah

    2015-06-01

    Neuromuscular disease can present many challenges to monitoring technologists in the operating room. This became evident when we received a request to monitor a patient with Charcot-Marie-Tooth disease during posterior spinal instrumentation and fusion for scoliosis. It has been well documented that the nerve conduction velocity is delayed with Charcot-Marie-Tooth disease (Pareyson et al. 2006). The latencies we normally encounter for somatosensory and motor evoked potentials for the upper extremity responses are between 15 and 20 msec, and for the lower extremity responses, are usually between 25 and 35 msec. Recording with a sweep of 100 msec, we assumed we could record a response with a significant delay. We never imagined we would need to increase the sweep time to 500 msec or more in order to record the responses from the lower extremities. PMID:26173348

  5. NUMERICAL MODELING AND UNCERTAINTIES IN RATE COEFFICIENTS FOR METHANE UTILIZATION AND TCE COMETABOLISM BY A METHANE OXIDIZING MIXED CULTURE. (R825689C036)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  6. DECHLORINATION OF TRICHLOROETHYLENE USING ELECTROCHEMICAL METHODS

    EPA Science Inventory

    Electrochemical degradation (ECD) is used to decontaminate organic and inorganic contaminants through oxidative or reductive processes. The ECD of Trichloroethylene (TCE) dechlorinates TCE through electric reduction. TCE dechlorination presented in the literature utilized electro...

  7. EFFECTS OF REACTION PARAMETERS ON ELECTROCHEMICAL DECHLORINATION OF TRICHLOROETHYLENE RATE AND BY-PRODUCTS

    EPA Science Inventory

    Trichloroethylene (TCE) was electrochemically dechlorinated in aqueous environments using granular graphite cathode in a mixed reactor. Effects of pH, current, electrolyte type, and flow rate on TCE dechlorination rate were evaluated. TCE dechlorination rate constant and gas prod...

  8. EFFECTS OF REACTOR CONDITIONS ON ELECTROCHEMICAL DECHLORINATION OF TRICHLOROETHYLENE USING GRANULAR-GRAPHITE ELECTRODE.

    EPA Science Inventory

    Trichloroethylene (TCE) was electrochemically dechlorinated in aqueous environments using granular graphite cathode in a mixed reactor. Effects of pH, current, electrolyte type, and flow rate on TCE dechlorination rate were evaluated. TCE dechlorination rate constant and gas pr...

  9. EFFECTS OF REACTOR CONDITIONS ON ELECTROCHEMICAL DECHLORINATION OF TRICHLOROETHYLENE USING GRANULAR-GRAPHITE ELECTRODE

    EPA Science Inventory

    Trichloroethylene (TCE) was electrochemically dechlorinated in aqueous environments using granular graphite cathode in a mixed reactor. Effects of pH, current, electrolyte type, and flow rate on TCE dechlorination rate were evaluated. TCE dechlorination rate constant and gas pr...

  10. Biodegradation of Chlorinated Solvents: Reactions near DNAPL and Enzyme Function

    SciTech Connect

    McCarty, P. L.; Spormann, Alfred M.; Criddle, Craig, S.

    2003-12-11

    Chlorinated solvents are among the most widespread groundwater contaminants in the country, contamination which is also among the most difficult and expensive for remediation. These solvents are biodegradable in the absence of oxygen, but this biodegradation requires both a food source for the organisms (electron donor) and the presence of chlorinated solvent biodegrading organisms. These two requirements are present naturally at some contamination sites, leading to natural attenuation of the solvents. If one or both requirements are absent, then engineered bioremediation either through addition of an external electron donor or through bioaugmentation with appropriate microorganisms, or both, may be used for site remediation. The most difficult case for cleanup is when a large residual of undissolved chlorinated solvents are present, residing as dense -non-aqueous-phase- liquid ( DNAPL). A major focus of this study was on the potential for biodegradation of the solvents when pre sent as DNAPL where concentrations are very high and potential for toxicity to microorganisms exist. Another focus was on a better understanding of the biological mechanisms involved in chlorinated solvent biodegradation . These studies were directed towards the chlorinated solvents, trichloroethene (TCE), tetrachloroethene or perchloroethene (PCE), and carbon tetrachloride (CT). The potential for biodegradation of TCE and PCE DNAPL was clearly demonstrated in this research. From column soil studies and batch studies we found there to be a clear advantage in focusing efforts at bioremediation near the DNAPL. Here, chlorinated solvent concentrations are the highest, both because of more favorable reaction kinetics and because such high solvent concentrations are toxic to microorganisms, such as methanogens, which compete with dehalogenators for the electron donor. Additionally, biodegradation near a PCE DNAPL results in an enhanced dissolution rate for the chlorinated solvent, by factors of three to five times, leading to a more rapid clean-up of the DNAPL zone. The most favored electron donor to add is one which partitions well with the chlorinated solvent or can be concentrated near it. Unfortunately, an ideal electron donor, such as vegetable oil, is difficult to introduce and mix with DNAPL in the ground, doing this properly remains an engineering challenge. Numerical model studies have indicated that several factors may significantly influence the rate and extent of enhancement, including the inhibitory effects of PCE and cDCE, the level of ED concentration, DNAPL configuration, and competition for ED. Such factors need to be considered when contemplating engineered DNAPL bioremediation. Pseudomonas stuzeri KC is an organism that transforms CT to carbon dioxide and chloride without the formation of the hazardous intermediate, chloroform. This is accomplished by production and secretion of a molecule called PDTC. This study was direct ed towards determining how PDTC works. Cu (II) at a ratio of 1:1 Cu to PDTC was found to result in the most rapid CT transformation, confirming that the PDTC-Cu complex is both a reactant and a catalyst in CT transformation. CT degradation requires that the PDTC be in a reduced form, which is generated by contact with cell components. Fe(II) inhibits CT transformation by PDTC. Studies indicated that this inhibition is enhanced by some compound or factor in the supernatant with molecular weight greater than 10,000 Da. We have made progress in determining what this factor might be, but have not yet been able to identify it. In related studies, we found that CT transformation by another organism, Shewanella oneidensis MR1, also involves an excreted factor, but this factor is different from PDTC and results in chloroform transformation as an intermediate. Our studies have indicated that this factor is similar to vitamin K2, and we have also confirmed that vitamin K2 does transform C T into chloroform.

  11. Measurement of air exchange rate of stationary vehicles and estimation of in-vehicle exposure.

    PubMed

    Park, J H; Spengler, J D; Yoon, D W; Dumyahn, T; Lee, K; Ozkaynak, H

    1998-01-01

    The air exchange rates or air changes per hour (ACH) were measured under 4 conditions in 3 stationary automobiles. The ACH ranged between 1.0 and 3.0 h-1 with windows closed and no mechanical ventilation, between 1.8 and 3.7 h-1 for windows closed with fan set on recirculation, between 13.3 and 26.1 h-1 for window open with no mechanical ventilation, and between 36.2 and 47.5 h-1 for window closed with the fan set on fresh air. ACHs for windows closed with no ventilation were higher for the older automobile than for the newer automobiles. With the windows closed and fan turned off, ACH was not influenced by wind speed (p > 0.05). When the window was open, ACH appeared to be greatly affected by wind speed (R2 = 0.86). These measurements are relevant to understanding exposures inside automobiles to sources such as dry-cleaned clothes, cigarettes and airbags. Therefore, to understand the in-vehicle exposure to these internal sources, perchloroethylene (PCE) emitted from dry-cleaned clothes and environmental tobacco smoke (ETS) inside a vehicle were modeled for simulated driving cycles. Airbag deployment was also modeled for estimating exposure level to alkaline particulate and carbon monoxide (CO). Average exposure to PCE inside a vehicle for 30 minutes period was high (approximately 780 micrograms/m3); however, this is only 6% of the two-week exposure that is influenced by the storage of dry cleaned clothing at home. On the other hand, the exposure levels of respirable suspended particulate (RSP) and formaldehyde due to ETS could reach 2.1 mg/m3 and 0.11 ppm, respectively, when a person smokes inside a driving car even with the window open. In modeling the in-vehicle concentrations following airbag deployment, the average CO level over 20 minutes would not appear to present problem (less than 28 ppm). The peak concentration of respirable particulate would have exceeded 140 mg/m3. Since most of the particle mass is composed of alkaline material, these high levels might be expected to cause harmful effects on susceptible people, such as asthmatics. In all modeled cases, ACH would significantly affect build-up and dilution of pollutants originating from internal sources. Frequent stopping in congested urban traffic can greatly increase short-term exposures. PMID:9470106

  12. MODELING VOLATILE ORGANIC COMPOUND PHARMACOKINETICS IN RAT PUPS

    EPA Science Inventory

    PBPK model predictions of internal dosimetry in young rats were compared to adult animals for benzene, chloroform (CHL), methylene chloride, methyl ethly ketone (MEK), perchloroethylene, and trichloroethylene.

  13. 40 CFR Table 4 to Subpart F of... - Organic Hazardous Air Pollutants Subject to Cooling Tower Monitoring Requirements in § 63.104

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Phosgene 75445 Propionaldehyde 123386 Propylene dichloride (1,2-Dichloropropane) 78875 Propylene oxide 75569 Quinone 106514 Styrene 100425 Tetrachloroethane (1,1,2,2-) 79345 Tetrachloroethylene (Perchloroethylene)...

  14. 40 CFR Table 4 to Subpart F of... - Organic Hazardous Air Pollutants Subject to Cooling Tower Monitoring Requirements in § 63.104

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Phosgene 75445 Propionaldehyde 123386 Propylene dichloride (1,2-Dichloropropane) 78875 Propylene oxide 75569 Quinone 106514 Styrene 100425 Tetrachloroethane (1,1,2,2-) 79345 Tetrachloroethylene (Perchloroethylene)...

  15. 40 CFR Table 4 to Subpart F of... - Organic Hazardous Air Pollutants Subject to Cooling Tower Monitoring Requirements in § 63.104

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Phosgene 75445 Propionaldehyde 123386 Propylene dichloride (1,2-Dichloropropane) 78875 Propylene oxide 75569 Quinone 106514 Styrene 100425 Tetrachloroethane (1,1,2,2-) 79345 Tetrachloroethylene (Perchloroethylene)...

  16. 40 CFR Table 4 to Subpart F of... - Organic Hazardous Air Pollutants Subject to Cooling Tower Monitoring Requirements in § 63.104

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Phosgene 75445 Propionaldehyde 123386 Propylene dichloride (1,2-Dichloropropane) 78875 Propylene oxide 75569 Quinone 106514 Styrene 100425 Tetrachloroethane (1,1,2,2-) 79345 Tetrachloroethylene (Perchloroethylene)...

  17. 40 CFR 60.16 - Priority list.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Surface Coating: Paper 5. Dry Cleaning (a) Perchloroethylene (b) Petroleum solvent 6. Graphic Arts 7... Production 30. Secondary Aluminum 31. Potash (Deleted) 32. Lightweight Aggregate Industry: Clay, Shale,...

  18. 40 CFR 60.16 - Priority list.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Surface Coating: Paper 5. Dry Cleaning (a) Perchloroethylene (b) Petroleum solvent 6. Graphic Arts 7... Production 30. Secondary Aluminum 31. Potash (Deleted) 32. Lightweight Aggregate Industry: Clay, Shale,...

  19. 40 CFR 60.16 - Priority list.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Surface Coating: Paper 5. Dry Cleaning (a) Perchloroethylene (b) Petroleum solvent 6. Graphic Arts 7... Production 30. Secondary Aluminum 31. Potash (Deleted) 32. Lightweight Aggregate Industry: Clay, Shale,...

  20. 40 CFR 60.16 - Priority list.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Surface Coating: Paper 5. Dry Cleaning (a) Perchloroethylene (b) Petroleum solvent 6. Graphic Arts 7... Production 30. Secondary Aluminum 31. Potash (Deleted) 32. Lightweight Aggregate Industry: Clay, Shale,...

  1. Assessment of Soil-Gas, Surface-Water, and Soil Contamination at the Installation Railhead, Fort Gordon, Georgia, 2008-2009

    USGS Publications Warehouse

    Landmeyer, James E.; Harrelson, Larry G.; Ratliff, W. Hagan; Wellborn, John B.

    2010-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of the Army Environmental and Natural Resources Management Office of the U.S. Army Signal Center and Fort Gordon, assessed soil gas, surface water, and soil for contaminants at the Installation Railhead (IR) at Fort Gordon, Georgia, from October 2008 to September 2009. The assessment included delineation of organic contaminants present in soil-gas samples beneath the IR, and in a surface-water sample collected from an unnamed tributary to Marcum Branch in the western part of the IR. Inorganic contaminants were determined in a surface-water sample and in soil samples. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samples collected within a localized area on the western part of the IR contained total petroleum hydrocarbons; benzene, toluene, ethylbenzene, and total xylenes (referred to as BTEX); and naphthalene above the method detection level. These soil-gas samples were collected where buildings had previously stood. Soil-gas samples collected within a localized area contained perchloroethylene (PCE). These samples were collected where buildings 2410 and 2405 had been. Chloroform and toluene were detected in a surface-water sample collected from an unnamed tributary to Marcum Branch but at concentrations below the National Primary Drinking Water Standard maximum contaminant level (MCL) for each compound. Iron was detected in the surface-water sample at 686 micrograms per liter (ug/L) and exceeded the National Secondary Drinking Water Standard MCL for iron. Metal concentrations in composite soil samples collected at three locations from land surface to a depth of 6 inches did not exceed the U.S. Environmental Protection Agency Regional Screening Levels for industrial soil.

  2. Modeling the effects of naturally occurring organic carbon on chlorinated ethene transport to a public supply well.

    PubMed

    Chapelle, Francis H; Kauffman, Leon J; Widdowson, Mark A

    2014-09-01

    The vulnerability of public supply wells to chlorinated ethene (CE) contamination in part depends on the availability of naturally occurring organic carbon to consume dissolved oxygen (DO) and initiate reductive dechlorination. This was quantified by building a mass balance model of the Kirkwood-Cohansey aquifer, which is widely used for public water supply in New Jersey. This model was built by telescoping a calibrated regional three-dimensional (3D) MODFLOW model to the approximate capture zone of a single public supply well that has a history of CE contamination. This local model was then used to compute a mass balance between dissolved organic carbon (DOC), particulate organic carbon (POC), and adsorbed organic carbon (AOC) that act as electron donors and DO, CEs, ferric iron, and sulfate that act as electron acceptors (EAs) using the Sequential Electron Acceptor Model in three dimensions (SEAM3D) code. SEAM3D was constrained by varying concentrations of DO and DOC entering the aquifer via recharge, varying the bioavailable fraction of POC in aquifer sediments, and comparing observed and simulated vertical concentration profiles of DO and DOC. This procedure suggests that approximately 15% of the POC present in aquifer materials is readily bioavailable. Model simulations indicate that transport of perchloroethene (PCE) and its daughter products trichloroethene (TCE), cis-dichloroethene (cis-DCE), and vinyl chloride (VC) to the public supply well is highly sensitive to the assumed bioavailable fraction of POC, concentrations of DO entering the aquifer with recharge, and the position of simulated PCE source areas in the flow field. The results are less sensitive to assumed concentrations of DOC in aquifer recharge. The mass balance approach used in this study also indicates that hydrodynamic processes such as advective mixing, dispersion, and sorption account for a significant amount of the observed natural attenuation in this system. PMID:24372440

  3. Modeling the Effects of Naturally Occurring Organic Carbon on Chlorinated Ethene Transport to a Public Supply Well†

    PubMed Central

    Chapelle, Francis H; Kauffman, Leon J; Widdowson, Mark A

    2014-01-01

    The vulnerability of public supply wells to chlorinated ethene (CE) contamination in part depends on the availability of naturally occurring organic carbon to consume dissolved oxygen (DO) and initiate reductive dechlorination. This was quantified by building a mass balance model of the Kirkwood-Cohansey aquifer, which is widely used for public water supply in New Jersey. This model was built by telescoping a calibrated regional three-dimensional (3D) MODFLOW model to the approximate capture zone of a single public supply well that has a history of CE contamination. This local model was then used to compute a mass balance between dissolved organic carbon (DOC), particulate organic carbon (POC), and adsorbed organic carbon (AOC) that act as electron donors and DO, CEs, ferric iron, and sulfate that act as electron acceptors (EAs) using the Sequential Electron Acceptor Model in three dimensions (SEAM3D) code. SEAM3D was constrained by varying concentrations of DO and DOC entering the aquifer via recharge, varying the bioavailable fraction of POC in aquifer sediments, and comparing observed and simulated vertical concentration profiles of DO and DOC. This procedure suggests that approximately 15% of the POC present in aquifer materials is readily bioavailable. Model simulations indicate that transport of perchloroethene (PCE) and its daughter products trichloroethene (TCE), cis-dichloroethene (cis-DCE), and vinyl chloride (VC) to the public supply well is highly sensitive to the assumed bioavailable fraction of POC, concentrations of DO entering the aquifer with recharge, and the position of simulated PCE source areas in the flow field. The results are less sensitive to assumed concentrations of DOC in aquifer recharge. The mass balance approach used in this study also indicates that hydrodynamic processes such as advective mixing, dispersion, and sorption account for a significant amount of the observed natural attenuation in this system. PMID:24372440

  4. Selective Enrichment Yields Robust Ethene-Producing Dechlorinating Cultures from Microcosms Stalled at cis-Dichloroethene

    PubMed Central

    Delgado, Anca G.; Kang, Dae-Wook; Nelson, Katherine G.; Fajardo-Williams, Devyn; Miceli, Joseph F.; Done, Hansa Y.; Popat, Sudeep C.; Krajmalnik-Brown, Rosa

    2014-01-01

    Dehalococcoides mccartyi strains are of particular importance for bioremediation due to their unique capability of transforming perchloroethene (PCE) and trichloroethene (TCE) to non-toxic ethene, through the intermediates cis-dichloroethene (cis-DCE) and vinyl chloride (VC). Despite the widespread environmental distribution of Dehalococcoides, biostimulation sometimes fails to promote dechlorination beyond cis-DCE. In our study, microcosms established with garden soil and mangrove sediment also stalled at cis-DCE, albeit Dehalococcoides mccartyi containing the reductive dehalogenase genes tceA, vcrA and bvcA were detected in the soil/sediment inocula. Reductive dechlorination was not promoted beyond cis-DCE, even after multiple biostimulation events with fermentable substrates and a lengthy incubation. However, transfers from microcosms stalled at cis-DCE yielded dechlorination to ethene with subsequent enrichment cultures containing up to 109 Dehalococcoides mccartyi cells mL?1. Proteobacterial classes which dominated the soil/sediment communities became undetectable in the enrichments, and methanogenic activity drastically decreased after the transfers. We hypothesized that biostimulation of Dehalococcoides in the cis-DCE-stalled microcosms was impeded by other microbes present at higher abundances than Dehalococcoides and utilizing terminal electron acceptors from the soil/sediment, hence, outcompeting Dehalococcoides for H2. In support of this hypothesis, we show that garden soil and mangrove sediment microcosms bioaugmented with their respective cultures containing Dehalococcoides in high abundance were able to compete for H2 for reductive dechlorination from one biostimulation event and produced ethene with no obvious stall. Overall, our results provide an alternate explanation to consolidate conflicting observations on the ubiquity of Dehalococcoides mccartyi and occasional stalling of dechlorination at cis-DCE; thus, bringing a new perspective to better assess biological potential of different environments and to understand microbial interactions governing bioremediation. PMID:24950250

  5. Quantifying urban/industrial emissions of greenhouse and ozone-depleting gases based on atmospheric observations

    NASA Astrophysics Data System (ADS)

    Barnes, Diana Hart

    2000-11-01

    Background and pollution trends and cycles of fourteen trace gases over the Northeastern U.S. are inferred from continuous atmospheric observations at the Harvard Forest research station located in Petersham, Massachusetts. This site receives background `clean' air from the northwest (Canada) and `dirty' polluted air from the southwest (New York City-Washington, D.C. corridor). Mixing ratios of gases regulated by the Montreal Protocol or other policies (CO, PCE, CFC11, CFC12, CFC113, CH 3CCl3, CCl4, and Halon-1211) and of those not subject to restrictions (H2, CH4, CHCl3, TCE, N2O, and SF6) were measured over the three-year period, 1996 to 1998, every 24 minutes by a fully automated gas chromatographic instrument with electron capture detectors. Evidence for polar vortex venting is found consistently in the month of June of the background seasonal cycles. The ratio of CO and PCE enhancements borne on southwesterly winds are in excellent agreement with county-level EPA and sales-based inventories for the New York City-Washington, D.C. region. From this firm footing, we use CO and PCE as reference compounds to determine the urban/industrial source strengths for the other species. A broad historical and geographic study of emissions reveals that the international treaty has by and large been a success. Locally, despite the passing of the 1996 Montreal Protocol ban, only emissions of CFC12 and CH3CCl3 are abating. Though source strengths are waning, the sources are not spent and continued releases to the atmosphere may be expected for some years to come. For CH3CCl3, whose rate of decline is central to our understanding of atmospheric processes, we estimate that absolute concentrations may persist until around the year 2010. The long-term high frequency time series of hydrogen provided here represents the first such data set of its kind. The H2 diurnal cycle is established and explained in terms of its sources and sinks. The ratio of H2 to CO in pollution plumes is found to be a seasonal and unchanged since early automobile exhaust studies of the 1960s, despite the many restrictions placed on car emissions and fuels since that time. Based on this result, a spatial inventory of H2 emissions from fossil fuel combustion is developed at the county level for the entire Northeastern U.S.

  6. Changes in Groundwater Flow and Volatile Organic Compound Concentrations at the Fischer and Porter Superfund Site, Warminster Township, Bucks County, Pennsylvania, 1993-2009

    USGS Publications Warehouse

    Sloto, Ronald A.

    2010-01-01

    The 38-acre Fischer and Porter Company Superfund Site is in Warminster Township, Bucks County, Pa. Historically, as part of the manufacturing process, trichloroethylene (TCE) degreasers were used for parts cleaning. In 1979, the Bucks County Health Department detected TCE and other volatile organic compounds (VOCs) in water from the Fischer and Porter on-site supply wells and nearby public-supply wells. The Fischer and Porter Site was designated as a Superfund Site and placed on the National Priorities List in September 1983. A 1984 Record of Decision for the site required the Fischer and Porter Company to pump and treat groundwater contaminated by VOCs from three on-site wells at a combined rate of 75 gallons per minute to contain groundwater contamination on the property. Additionally, the Record of Decision recognized the need for treatment of the water from two nearby privately owned supply wells operated by the Warminster Heights Home Ownership Association. In 2004, the Warminster Heights Home Ownership Association sold its water distribution system, and both wells were taken out of service. The report describes changes in groundwater levels and contaminant concentrations and migration caused by the shutdown of the Warminster Heights supply wells and presents a delineation of the off-site groundwater-contamination plume. The U.S. Geological Survey (USGS) conducted this study (2006-09) in cooperation with the U.S. Environmental Protection Agency (USEPA). The Fischer and Porter Site and surrounding area are underlain by sedimentary rocks of the Stockton Formation of Late Triassic age. The rocks are chiefly interbedded arkosic sandstone and siltstone. The Stockton aquifer system is comprised of a series of gently dipping lithologic units with different hydraulic properties. A three-dimensional lithostratigraphic model was developed for the site on the basis of rock cores and borehole geophysical logs. The model was simplified by combining individual lithologic units into generalized units representing upward fining sedimentary cycles capped by a siltstone bed. These cycles were labeled units 1 through 8 and are called stratigraphic units in this report. Groundwater in the unweathered zone mainly moves through a network of interconnecting secondary openings--bedding-plane fractures and joints. Groundwater generally is unconfined in the shallower part of the aquifer and confined or semiconfined in the deeper part of the aquifer. The migration of VOCs from the Fischer and Porter Site source area is influenced by geologic and hydrologic controls. The hydrologic controls have changed with time. Stratigraphic units 2 and 3 crop out beneath the former Fischer and Porter plant. VOCs originating at the plant source area entered these stratigraphic units and moved downdip to the northwest. When the wells at and in the vicinity of the site were initially sampled in 1979-80, three public-supply wells (BK-366, BK-367, MG-946) and three industrial-supply wells (BK-368, BK-370, and BK-371) were pumping. Groundwater contaminated with VOCs flowed downdip and then northeast along strike toward well BK-366, downdip toward well BK-368, and downdip and then west along strike toward well MG-946. The long axis of the TCE plume is oriented about N. 18? W. in the direction of dip. In 1979-80, the leading edge of the plume was about 3,500 feet wide. With the cessation of pumping of the supply wells in 2004, the size of the plume has decreased. In 2007-09, the plume was approximately 2,000 feet long and 2,000 feet wide at the leading edge. On the western side of the site, TCE and tetrachloroethylene (PCE) appear to be moving downdip though stratigraphic unit 3. The downdip extent of TCE and PCE migration extended approximately 550 feet off-site to the northwest and 750 feet off-site to the north. TCE concentrations in water samples from wells at the western site boundary increased from 1996 to 2007. On the northern side of the site, TCE and P

  7. 75 FR 61662 - State of California; Request for Approval of Section 112(l) Authority for Hazardous Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-06

    ...EPA is proposing to approve California's Airborne Toxic Control Measure for Emissions of Perchloroethylene from Dry Cleaning and Water-Repelling Operations, Requirements for Perc Manufacturers, and Requirements for Perc Distributors to be implemented and enforced in place of the National Perchloroethylene Air Emission Standards for Dry Cleaning Facilities. EPA is proposing this action under......

  8. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... Biweekly means any 14-day period of time. Carbon adsorber means a bed of activated carbon into which an air-perchloroethylene gas-vapor stream is routed and which adsorbs the perchloroethylene on the carbon. Coin-operated... installation of a dry cleaning system subject to this subpart. Desorption means regeneration of a...

  9. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... Biweekly means any 14-day period of time. Carbon adsorber means a bed of activated carbon into which an air-perchloroethylene gas-vapor stream is routed and which adsorbs the perchloroethylene on the carbon. Coin-operated... installation of a dry cleaning system subject to this subpart. Desorption means regeneration of a...

  10. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... Biweekly means any 14-day period of time. Carbon adsorber means a bed of activated carbon into which an air-perchloroethylene gas-vapor stream is routed and which adsorbs the perchloroethylene on the carbon. Coin-operated... installation of a dry cleaning system subject to this subpart. Desorption means regeneration of a...

  11. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... Biweekly means any 14-day period of time. Carbon adsorber means a bed of activated carbon into which an air-perchloroethylene gas-vapor stream is routed and which adsorbs the perchloroethylene on the carbon. Coin-operated... installation of a dry cleaning system subject to this subpart. Desorption means regeneration of a...

  12. 40 CFR 63.321 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... Biweekly means any 14-day period of time. Carbon adsorber means a bed of activated carbon into which an air-perchloroethylene gas-vapor stream is routed and which adsorbs the perchloroethylene on the carbon. Coin-operated... installation of a dry cleaning system subject to this subpart. Desorption means regeneration of a...

  13. 40 CFR 63.323 - Test methods and monitoring.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Perchloroethylene Air Emission Standards for Dry Cleaning Facilities § 63.323 Test methods and monitoring. (a) When... air-perchloroethylene gas-vapor stream on the outlet side of the refrigerated condenser on a dry-to-dry machine, dryer, or reclaimer with a temperature sensor to determine if it is equal to or less...

  14. Replacement Technologies for Precision Cleaning of Aerospace Hardware for Propellant Service

    NASA Technical Reports Server (NTRS)

    Beeson, Harold; Kirsch, Mike; Hornung, Steven; Biesinger, Paul

    1997-01-01

    The NASA White Sands Test Facility (WSTF) is developing cleaning and verification processes to replace currently used chlorofluorocarbon-l13- (CFC-113-) based processes. The processes being evaluated include both aqueous- and solvent-based techniques. Replacement technologies are being investigated for aerospace hardware and for gauges and instrumentation. This paper includes the findings of investigations of aqueous cleaning and verification of aerospace hardware using known contaminants, such as hydraulic fluid and commonly used oils. The results correlate nonvolatile residue with CFC 113. The studies also include enhancements to aqueous sampling for organic and particulate contamination. Although aqueous alternatives have been identified for several processes, a need still exists for nonaqueous solvent cleaning, such as the cleaning and cleanliness verification of gauges used for oxygen service. The cleaning effectiveness of tetrachloroethylene (PCE), trichloroethylene (TCE), ethanol, hydrochlorofluorocarbon 225 (HCFC 225), HCFC 141b, HFE 7100(R), and Vertrel MCA(R) was evaluated using aerospace gauges and precision instruments and then compared to the cleaning effectiveness of CFC 113. Solvents considered for use in oxygen systems were also tested for oxygen compatibility using high-pressure oxygen autogenous ignition and liquid oxygen mechanical impact testing.

  15. Development of CFC-Free Cleaning Processes at the NASA White Sands Test Facility

    NASA Technical Reports Server (NTRS)

    Beeson, Harold; Kirsch, Mike; Hornung, Steven; Biesinger, Paul

    1995-01-01

    The NASA White Sands Test Facility (WSTF) is developing cleaning and verification processes to replace currently used chlorofluorocarbon-113- (CFC-113-) based processes. The processes being evaluated include both aqueous- and solvent-based techniques. The presentation will include the findings of investigations of aqueous cleaning and verification processes that are based on a draft of a proposed NASA Kennedy Space Center (KSC) cleaning procedure. Verification testing with known contaminants, such as hydraulic fluid and commonly used oils, established correlations between nonvolatile residue and CFC-113. Recoveries ranged from 35 to 60 percent of theoretical. WSTF is also investigating enhancements to aqueous sampling for organics and particulates. Although aqueous alternatives have been identified for several processes, a need still exists for nonaqueous solvent cleaning, such as the cleaning and cleanliness verification of gauges used for oxygen service. The cleaning effectiveness of tetrachloroethylene (PCE), trichloroethylene (TCE), ethanol, hydrochlorofluorocarbon-225 (HCFC-225), tert-butylmethylether, and n-Hexane was evaluated using aerospace gauges and precision instruments and then compared to the cleaning effectiveness of CFC-113. Solvents considered for use in oxygen systems were also tested for oxygen compatibility using high-pressure oxygen autoignition and liquid oxygen mechanical impact testing.

  16. ADVANCEMENT OF NUCLEIC ACID-BASED TOOLS FOR MONITORING IN SITU REDUCTIVE DECHLORINATION

    SciTech Connect

    Vangelas, K; ELIZABETH EDWARDS, E; FRANK LOFFLER, F; Brian02 Looney, B

    2006-11-17

    Regulatory protocols generally recognize that destructive processes are the most effective mechanisms that support natural attenuation of chlorinated solvents. In many cases, these destructive processes will be biological processes and, for chlorinated compounds, will often be reductive processes that occur under anaerobic conditions. The existing EPA guidance (EPA, 1998) provides a list of parameters that provide indirect evidence of reductive dechlorination processes. In an effort to gather direct evidence of these processes, scientists have identified key microorganisms and are currently developing tools to measure the abundance and activity of these organisms in subsurface systems. Drs. Edwards and Luffler are two recognized leaders in this field. The research described herein continues their development efforts to provide a suite of tools to enable direct measures of biological processes related to the reductive dechlorination of TCE and PCE. This study investigated the strengths and weaknesses of the 16S rRNA gene-based approach to characterizing the natural attenuation capabilities in samples. The results suggested that an approach based solely on 16S rRNA may not provide sufficient information to document the natural attenuation capabilities in a system because it does not distinguish between strains of organisms that have different biodegradation capabilities. The results of the investigations provided evidence that tools focusing on relevant enzymes for functionally desired characteristics may be useful adjuncts to the 16SrRNA methods.

  17. Raman probe. Innovative technology summary report

    SciTech Connect

    1999-07-01

    The Raman probe is deployed in high-level waste tanks with the cone penetrometer (CPT). These technologies are engineered and optimized to work together. All of the hardware is radiation hardened, designed for and tested in the high-radiation, highly caustic chemical environment of US Department of Energy`s (DOE`s) waste storage tanks. When deployed in tanks, the system is useful for rapidly assessing the species and concentrations of organic-bearing tank wastes. The CPT was originally developed for geological and groundwater applications, with sensors that measure physical parameters such as soil moisture, temperature, and pH. When deployed, it is hydraulically forced directly into the ground rather than using boring techniques utilized by rotary drilling systems. There is a separate Innovative Technology Summary Report for the CPT, so this report will focus on the changes made specifically to support the Raman probe. The most significant changes involve adapting the Raman probe for in-tank and subsurface field use and developing meaningful real-time data analysis. Testing of the complete LLNL system was conducted in a hot cell in the 222-S Laboratory at the Hanford site in summer 1997. Both instruments were tested in situ on solvent-contaminated soils (TCE and PCE) at the Savannah River Site in February and June 1998. This report describes the technology, its performance, its uses, cost, regulatory and policy issues, and lessons learned.

  18. Savannah River Site A/M Area Southern Sector Characterization Cone Penetrometer Report

    SciTech Connect

    Raabe, B.A.

    1993-05-01

    The Savannah River Site (SRS) is located in the Atlantic Coastal Plaingeologic province. This area is characterized by low relief, predominantly unconsolidated sediments of Cretaceous though Tertiary age. A multiple aquifer system underlies the A/M Area and affects the definition and distribution of a contaminant plume. The water table and uppermost confined aquifer (Steed Pond Aquifer) are contaminated with elevated concentrations of trichloroethylene(TCE) and tetrachloroethylene (PCE) and their associated compounds. The deeper aquifers in this area have less widely spread chlorinated hydrocarbon contamination.Cone penetrometer testing was selected as the method of investigation because it is minimally invasive, offers advanced technological capabilities in gathering lithologic data, and offers groundwater sampling capabilities. CPT testing utilizes a hydraulic push tool system. The probe collects real-time data that is processed by computer into soil/lithology classifications. The system can also be used to collect sediment and soil vapor samples although these features were not utilized during this project. Advantages of the CPT system include a small borehole diameter which minimizes cross-contamination of lithologic units, virtual elimination of drill cuttings and fluids that require disposal, collection of various types of undisturbed sediment and water samples and plotting of hydrostratigraphic and lithologic data while in the field.

  19. Offshore passive soil vapor survey at a contaminated coastal site

    SciTech Connect

    Anderson, M.; Church, G.

    1998-06-01

    A high-resolution passive soil vapor survey was recently conducted at a coastal military base in southern California where a chlorinated and aromatic hydrocarbon plume threatens San Diego Bay. An existing sampling grid was extended offshore the entire length of the contaminated site. PETREX sampling tubes were emplaced conventionally onshore and were emplaced offshore in sandy bay-bottom sediments by divers working in 3 to 17 m (10 to 55 ft) of water. Results of mass spectrometric analysis of passive vapor samples were consistent with submarine ground water discharge measurements made previously with seepage meters, yet also produced one unexpected result: evidence of in situ degradation. Tetrachloroethene (PCE), widespread onshore, was not detected offshore. Trichloroethene (TCE), the primary contaminant onshore, was detected in only three points offshore. Dichloroethene (DCE), present only at trace levels onshore, was the dominant constituent measured in the offshore plume. Results were confirmed by laboratory analyses of sediment samples. The study demonstrated the utility of extending the passive soil vapor technique offshore in up to 17 m (55 ft) of sea water in a heavily trafficked waterway with a strong tidal current.

  20. Test plan for Geo-Cleanse{reg_sign} demonstration (in situ destruction of dense non-aqueous phase liquid (DNAPL))

    SciTech Connect

    Jerome, K.M.; Looney, B.B.; Accorsi, F.; Dingens, M.; Wilson, J.T.

    1996-09-01

    Soils and groundwater beneath an abandoned process sewer line in the A/M Area of the Savannah River Site (SRS) contain elevated levels of volatile organic compounds, specifically trichloroethylene (TCE) and tetrachloroethylene (PCE), two common chlorinated solvents. These compounds have low aqueous solubilities, thus when released to the subsurface in sufficient quantity, tend to exist as immiscible fluids or nonaqueous phase liquids (NAPLs). Because chlorinated solvents are also denser than water, they are referred to by the acronym DNAPLs, or dense non-aqueous phase liquids. Technologies targeted at the efficient characterization or removal of DNAPL are not currently proven. For example, most DNAPL studies rely on traditional soil and water sampling and the fortuitous observation of immiscible solvent. Once DNAPL is identified, soil excavation (which is only applicable to small contained spill sites) is the only proven cleanup method. New cleanup approaches based on destruction of DNAPL either in situ or ex situ have been proposed and tested at the pilot scale. The proposed demonstration, as described in this report will evaluate the applicability to DNAPL plumes of a technology proven for in situ destruction of light non-aqueous phase liquids (LNAPLs) such as oils.

  1. Cometabolic bioremediation

    SciTech Connect

    Hazen, Terry C.

    2009-02-15

    Cometabolic bioremediation is probably the most under appreciated bioremediation strategy currently available. Cometabolism strategies stimulate only indigenous microbes with the ability to degrade the contaminant and cosubstrate e.g. methane, propane, toluene and others. This highly targeted stimulation insures that only those microbes that can degrade the contaminant are targeted, thus reducing amendment costs, well and formation plugging, etc. Cometabolic bioremediation has been used on some of the most recalcitrant contaminants, e.g. PCE, TCE, MTBE, TNT, dioxane, atrazine, etc. Methanotrophs have been demonstrated to produce methane monooxygense, an oxidase that can degrade over 300 compounds. Cometabolic bioremediation also has the advantage of being able to degrade contaminants to trace concentrations, since the biodegrader is not dependent on the contaminant for carbon or energy. Increasingly we are finding that in order to protect human health and the environment that we must remediate to lower and lower concentrations, especially for compounds like endocrine disrupters, thus cometabolism may be the best and maybe the only possibility that we have to bioremediate some contaminants.

  2. Characterization and simulation of fate and transport of selected volatile organic compounds in the vicinities of the Hadnot Point Industrial Area and landfill: Chapter A Supplement 6 in Analyses and historical reconstruction of groundwater flow, contaminant fate and transport, and distribution of drinking water within the service areas of the Hadnot Point and Holcomb Boulevard Water Treatment Plants and vicinities, U.S. Marine Corps Base Camp Lejeune, North Carolina

    USGS Publications Warehouse

    Jones, L. Elliott; Suárez-Soto, René J.; Anderson, Barbara A.; Maslia, Morris L.

    2013-01-01

    This supplement of Chapter A (Supplement 6) describes the reconstruction (i.e. simulation) of historical concentrations of tetrachloroethylene (PCE), trichloroethylene (TCE), and benzene3 in production wells supplying water to the Hadnot Base (USMCB) Camp Lejeune, North Carolina (Figure S6.1). A fate and transport model (i.e., MT3DMS [Zheng and Wang 1999]) was used to simulate contaminant migration from source locations through the groundwater system and to estimate mean contaminant concentrations in water withdrawn from water-supply wells in the vicinity of the Hadnot Point Industrial Area (HPIA) and the Hadnot Point landfill (HPLF) area.4 The reconstructed contaminant concentrations were subsequently input into a flow-weighted, materials mass balance (mixing) model (Masters 1998) to estimate monthly mean concentrations of the contaminant in finished water 5 at the HPWTP (Maslia et al. 2013). The calibrated fate and transport models described herein were based on and used groundwater velocities derived from groundwater-flow models that are described in Suárez-Soto et al. (2013). Information data pertinent to historical operations of water-supply wells are described in Sautner et al. (2013) and Telci et al. (2013).

  3. Superfund Record of Decision (EPA Region 8): Mystery Bridge at Highway 20, Natrona County, WY. (First remedial action), September 1990

    SciTech Connect

    Not Available

    1990-09-24

    The Mystery Bridge at Highway 20 site is an industrial area with two onsite residential subdivisions, in Natrona County, one mile east of Evansville, Wyoming. A portion of the site lies within the 100- and 500-year floodplains of the North Platte River and Elkhorn Creek. Two plants are located at the site: the DOW/DSI facility, an oil and gas production enhancement service facility; and the KN plant, which is a natural gas fractionation, compression, cleaning, odorizing and transmission plant. The site overlies a contaminated alluvial aquifer. In 1965, an underground pipe burst, releasing 5,000 to 10,000 gallons of absorption oil from the KN facility into the soil. From 1965 to 1987, a flare pit was used by KN to collect spent materials and wastes, and an onsite catchment area was used to collect the contaminated surface runoff etc. In 1987, site investigations revealed the presence of aromatic hydrocarbons in the soil in this area. The Record of Decision (ROD) addresses remediation of the onsite ground water emanating from the DOW/DSI and KN facilities; the VHO and BETX plumes respectively. The primary contaminants of concern affecting the ground water are VOCs including benzene, PCE, TCE, toluene, and xylenes.

  4. Numerical Modeling of NAPL Source Zone Treatment

    NASA Astrophysics Data System (ADS)

    Hammond, G. E.; Valocchi, A. J.; Lichtner, P. C.

    2002-12-01

    Experience has demonstrated the poor performance of conventional approaches to remediating NAPL contaminated sites (e.g. pump-and-treat, air sparging, soil vapor extraction, etc.). More recently, researchers have been investigating novel approaches to NAPL source zone treatment such as the HERTZ (Halorespiration Enhancing Redox Transition Zone) technology for bioremediation where carbon sources are injected into the subsurface enhancing in situ reductive dechlorination of halogenated NAPLS (i.e. PCE, TCE). Although this innovative approach has proven effective in controlled small-scale laboratory experiments, this technology still remains relatively unverified at the field scale in a natural subsurface environment. One tool for evaluating the performance of HERTZ in the more complex subsurface is detailed numerical simulation through sophisticated biogeochemical transport modeling. Recent advances in computational science including superior computational hardware, more efficient numerical algorithms and increased understanding of the governing equations describing biogeochemical transport have enabled the use of numerical models to more accurately predict/validate the performance of different remediation strategies. In this presentation we investigate the use of numerical models to describe NAPL source zone treatment using HERTZ. The multicomponent reactive transport model PARTRAN is used in the simulations. This model is capable of tightly coupling three-dimensional transport and geochemical reaction on large, high-resolution grids through the use of parallel high-performance supercomputers. Simulations are carried out to investigate the influence of small-scale heterogeneities on retainment of NAPL contamination during remediation.

  5. Superfund Record of Decision (EPA Region 3): William Dick Lagoons, West Caln Township, Chester County, PA. (First remedial action), June 1991

    SciTech Connect

    Not Available

    1991-09-28

    The 4.4-acre William Dick Lagoons site is a chemical wastewater disposal site in West Caln Township, Chester County, Pennsylvania. An estimated 30 residences located within 1,000 feet of the site use private wells for their drinking water supply. Two other Superfund sites are near the site. From the 1950's to 1970, Mr. William Dick used the lagoons to dispose of wastewater left from cleaning the interiors of chemical and petroleum tank trailers owned primarily by Chemical Leaman Tank Lines, (CLTL), and residual chemical products. Later in 1970, vandalism caused the release of an estimated 300,000 gallons of wastewater into Birch Run, a tributary of the West Branch of Brandywine Creek. As a result of this discharge, more than 2,600 fish died, and water supplies that used Brandywine Creek as a water source were closed. The Record of Decision (ROD) provides an interim remedy and addresses contaminated residential water as Operable Unit 1 (OU1) and ground water as OU2. A future ROD will address source control and will provide a remedy for the cleanup of contaminated soil. The primary contaminants of concern affecting the ground water are VOCs including benzene, PCE, and TCE; other organics including phenols; and metals. The selected remedial action for the site is included.

  6. Superfund Record of Decision (EPA Region 10): Northside Landfill, Washington (First remedial action), September 1989. Final report

    SciTech Connect

    Not Available

    1989-09-30

    The 345-acre Northside Landfill is in a mixed residential and agricultural area, in the northwest corner of the city of Spokane, Spokane County, Washington. The landfill has been used since the 1930s by the city of Spokane and a variety of private and public haulers for disposal of residential and light commercial refuse. The landfill is divided into four disposal units: a refuse unit, a grease skimmings unit, an old open burn unit and a sewage sludge unit. Only the refuse unit is active; however, it is scheduled to close by 1992. The western one-third of the land fill lies over the large Spokane Valley-Rathdrum Prairie Aquifer (SVRPA). The SVRPA was designated as a sole source of water supply for the Spokane-Coeur d'Alene area by EPA in 1978. Investigations conducted in 1981 and 1983 indicated the presence of volatile organic compounds (VOCs) beneath the site and in offsite residential wells located northwest of the landfill. The city immediately supplied the 19 affected residences with bottled water and has since extended municipal water lines to the area. The primary contaminants of concern affecting the ground water are VOCs including PCE, TCA, and TCE. In addition, iron and lead exceed the secondary drinking water standards offsite.

  7. Test plan for single well injection/extraction characterization of DNAPL

    SciTech Connect

    Looney, B.B.; Jerome, K.M.; Burdick, S.; Rossabi, J.; Jarosch, T.R.; Eddy-Dilek, C.A.

    1995-12-01

    Soils and groundwater beneath an abandoned Process sewer line in the A/M Area of the Savannah River Site (SRS) contain elevated levels of volatile organic compounds, specifically trichloroethylene (TCE) and tetrachloroethylene (PCE), two common chlorinated solvents. These compounds have low aqueous solubilities, thus when released to the subsurface in sufficient quantity, tend to exist as immiscible fluids or nonaqueous phase liquids (NAPLs). Because chlorinated solvents are also denser than water, they are referred to by the acronym DNAPLS, or dense non aqueous Phase liquids. Technologies targeted at the efficient characterization or removal of DNAPL are not currently proven. For example, most DNAPL studies rely on traditional soil and water sampling and the fortuitous observation of immiscible solvent. Once DNAPL is identified, soil excavation (which is only applicable to small contained spill sites) is the only ``proven`` cleanup method. New cleanup approaches based on enhanced removal by surfactants and/or alcohols have been proposed and tested at the pilot scale. As described below, carefully designed experiments similar to the enhanced removal methods may provide important characterization information on DNAPLs.

  8. Soil pore-gas sampling by photoacoustic radiometry

    SciTech Connect

    Sollid, J.E.

    1994-11-01

    Concentrations of volatile organics in a soil pore-gas plume were measured using a commercially available multigas monitor. The monitor is a photoacoustic radiometer (PAR) controlled by an on-board, programmable microprocessor. The measurements determine the extent and location of the vapor plume in the subsurface. At least twelve wells surrounding the sources are measured quarterly. The sources are located in former liquid chemical waste disposal pits and shafts at Los Alamos National Laboratory. The primary constituents of the plume are 1,1,1 trichloroethane (TCA), trichloroethene (TCE), and tetrachloroethene or perchloroethene or perchloroethene (PCE). Four quarters of data are presented for TCA. All were used primarily as solvents and degreasers. Previously the composition of the vapor plume was determined by Gas Chromatography Mass Spectrometer GCMS methods. Photoacoustic radiometry and gas chromatography are discussed giving the advantages and disadvantages of each method, although in this program they are basically complementary. Gas chromatography is a more qualitative method to determine which analytes are present and the approximate concentration. Photoacoustic radiometry, to function well, requires foreknowledge of constituents and serves best to determine how much is present. Measurements are quicker and more direct with photoacoustic methods. Once the constituents to be measured are known, the cost to monitor is much less using photoacoustics, and the results are available more quickly.

  9. Predicting Optimal Resolving Power for Ambient Pressure Ion Mobility Spectrometry (IMS)

    PubMed Central

    Kanu, Abu B.; Gribb, Molly M.; Hill, Herbert H

    2010-01-01

    Although diffusion theory predicts that IMS resolving power increases with the square root of the voltage applied across the drift tube, in practice there exists an optimum voltage above which resolving power decreases. This optimum voltage was determined to be both compound and initial ion pulse width-dependent. A “conditional” resolving power equation is introduced that can be used to quickly approximate realistic resolving powers for specific instrumental operating parameters and compounds. Using four common environmental contaminants [trichloroethylene (TCE), tetrachloroethylene (PCE), methyl tert-butyl ether (MTBE) and methyl iso-butyl ketone (MIBK)], diffusion-limited (theoretical), Rd, conditional, Rc, and actual (or measured), Rm, IMS resolving powers were determined and compared for a small IMS instrument designed for subsurface measurements. Detection limits determined at the optimal resolving power for the environmental contaminants ranged from 18 parts per trillion volume-to-volume (pptv) to 80 parts per billion volume-to-volume (ppbv). The maximal measured resolving power for our small, ambient-pressure stand-alone IMS ranged from 42 to 54, yielding an IMS resolving power efficiency, defined as Rm/Rc × 100%, of 56 to 74% of the maximal conditional resolving power possible. PMID:18683951

  10. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    SciTech Connect

    Not Available

    1991-10-01

    In April 1990, Wright-Patterson Air Force Base (WPAFB) initiated an effort for the evaluation of potential removal of ground water contamination at the Base. This report presents a current assessment of the nature and extent of the contamination believed to be migrating across the southwestern boundary of Area C and the northern boundary of Area B based upon analysis of existing environmental data obtained from several sources. The existing data base indicates widespread, low-level contamination moving across Base boundaries at levels that pose no immediate threat to the Mad River Valley well fields. An investigation by the City of Dayton in May and June 1990, however, implies that a more identifiable plume of PCE and TCE may be crossing the southwestern boundary of Area C immediately downgradient of Landfill 5. More data is needed to delineate ground water contamination and to design and implement a suitable control system. This report concludes that although an extensive study of the boundaries in question would be the preferred approach, a limited, focused investigation and subsequent feasibility study can be accomplished with a reasonable certainty of achieving the desired outcome of this project.

  11. [Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio]. Volume 1, Site assessment report

    SciTech Connect

    Not Available

    1991-10-01

    In April 1990, Wright-Patterson Air Force Base (WPAFB) initiated an effort for the evaluation of potential removal of ground water contamination at the Base. This report presents a current assessment of the nature and extent of the contamination believed to be migrating across the southwestern boundary of Area C and the northern boundary of Area B based upon analysis of existing environmental data obtained from several sources. The existing data base indicates widespread, low-level contamination moving across Base boundaries at levels that pose no immediate threat to the Mad River Valley well fields. An investigation by the City of Dayton in May and June 1990, however, implies that a more identifiable plume of PCE and TCE may be crossing the southwestern boundary of Area C immediately downgradient of Landfill 5. More data is needed to delineate ground water contamination and to design and implement a suitable control system. This report concludes that although an extensive study of the boundaries in question would be the preferred approach, a limited, focused investigation and subsequent feasibility study can be accomplished with a reasonable certainty of achieving the desired outcome of this project.

  12. Applications of advanced oxidation processes: present and future.

    PubMed

    Suty, H; De Traversay, C; Cost, M

    2004-01-01

    The use of advanced oxidation processes (AOPs) to remove pollutants in various water treatment applications has been the subject of study for around 30 years. Most of the available processes (Fenton reagent, O3 under basic conditions, O3/H2O2, O3/UV, O3/solid catalyst, H2O2/M(n+), H2O2/UV, photo-assisted Fenton, H2O2/solid catalyst, H2O2/NaClO, TiO2/UV etc.) have been investigated in depth and a considerable body of knowledge has been built up about the reactivity of many pollutants. Various industrial applications have been developed, including ones for ground remediation (TCE, PCE), the removal of pesticides from drinking water, the removal of formaldehyde and phenol from industrial waste water and a reduction in COD from industrial waste water. The development of such AOP applications has been stimulated by increasingly stringent regulations, the pollution of water resources through agricultural and industrial activities and the requirement that industry meet effluent discharge standards. Nevertheless, it is difficult to obtain an accurate picture of the use of AOPs and its exact position in the range of water treatment processes has not been determined to date. The purpose of this overview is to discuss those processes and provide an indication of future trends. PMID:15077976

  13. Anionic surfactant remediation of soil columns contaminated by nonaqueous phase liquids

    NASA Astrophysics Data System (ADS)

    Dwarakanath, V.; Kostarelos, K.; Pope, Gary A.; Shotts, Doug; Wade, William H.

    1999-06-01

    A variety of column experiments have been completed for the purpose of selecting and evaluating suitable surfactants for remediation of nonaqueous phase liquids (NAPLs). The various NAPLs tested in the laboratory experiments were tetrachloroethylene (PCE), trichloroethylene (TCE), jet fuel (JP4) and a dense nonaqueous phase liquid from a site at Hill Air Force Base, UT. Both Ottawa sand and Hill field soil were used in these experiments. Surfactant candidates were first screened using phase behavior experiments and only the best ones were selected for the subsequent column experiments. Surfactants which showed high contaminant solubilization, fast coalescence times, and the absence of liquid crystal phases and gels during the phase behavior experiments were tested in soil column experiments. The primary objective of the soil column experiments was to identify surfactants that recovered at least 99% of the contaminant. The secondary objective was to identify surfactants that show low adsorption and little or no loss of hydraulic conductivity during the column experiments. Results demonstrated that up to 99.9% of the contaminants were removed as a result of surfactant flooding of the soil columns. The addition of xanthan gum polymer to the surfactant solution was shown to increase remediation efficiency as a lower volume of surfactant was required for recovering a given volume of NAPL. Based on these experimental results, guidelines for designing highly efficient and robust surfactant floods have been developed and applied to a field demonstration.

  14. Spatiotemporal changes of CVOC concentrations in karst aquifers: analysis of three decades of data from Puerto Rico.

    PubMed

    Yu, Xue; Ghasemizadeh, Reza; Padilla, Ingrid; Irizarry, Celys; Kaeli, David; Alshawabkeh, Akram

    2015-04-01

    We studied the spatial and temporal distribution patterns of Chlorinated Volatile Organic Compounds (CVOCs) in the karst aquifers in northern Puerto Rico (1982-2013). Seventeen CVOCs were widely detected across the study area, with the most detected and persistent contaminated CVOCs including trichloroethylene (TCE), tetrachloroethylene (PCE), carbon tetrachloride (CT), chloroform (TCM), and methylene chloride (DCM). Historically, 471 (76%) and 319 (52%) of the 615 sampling sites have CVOC concentrations above the detection limit and maximum contamination level (MCL), respectively. The spatiotemporal patterns of the CVOC concentrations showed two clusters of contaminated areas, one near the Superfund site "Upjohn" and another near "Vega Alta Public Supply Wells." Despite a decreasing trend in concentrations, there is a general northward movement and spreading of contaminants even beyond the extent of known sources of the Superfund and landfill sites. Our analyses suggest that, besides the source conditions, karst characteristics (high heterogeneity, complex hydraulic and biochemical environment) are linked to the long-term spatiotemporal patterns of CVOCs in groundwater. PMID:25522355

  15. Superfund record of decision (EPA Region 5): Eau Claire Municipal Well Field, Eau Claire County, Wisconsin. First remedial action, March 1988

    SciTech Connect

    Not Available

    1988-03-31

    The 500-acre Eau Claire Municipal Well Field (ECMWF) supplies drinking water to approximately 57,600 residents and numerous commercial establishments in the city of Eau Claire and Washington Township. Ground water from five municipal wells in the north well field is contaminated with VOCs. The contamination at the ECMWF site has been characterized as two separate plumes with the estimated volume of contamination at Plume 1 and 2 of 1.9 x 10/sup 8/ ft/sup 3/ and 2.6 x 10/sup 8/ ft/sup 3/, respectively. Concerned about the future use of the water supply, additional testing in September 1982 and January 1983 was conducted to identify the source and extent of VOC contamination. Several residential wells reported detectable levels of VOCs including, 1,1-dichloroethene concentrations in excess of the WDNR health advisory. The Eau Claire site was given a high Superfund NPL priority by WDNR due to the nature of the toxicity and persistence of the contaminants and the large population affected. The primary contaminants of concern affecting the ground water are VOCs and include: chloroform, DCE, dichloroethene, PCE, TCE, and trichloroethane. The selected remedial action for the site is proposed in the report. The estimated capital cost for the remedial action is $1,214,200 with annual OandM of $396,700.

  16. Effects of Agriculture and Urbanization on Quality of Shallow Ground Water in the Arid to Semiarid Western United States, 1993-2004

    USGS Publications Warehouse

    Paul, Angela P.; Seiler, Ralph L.; Rowe, Timothy G.; Rosen, Michael R.

    2007-01-01

    Within the Western United States, agricultural and rural lands are being developed into commercial and residential areas. With changes in land use and increasing population, greater demands are placed on water resources for agricultural, industrial, and domestic supplies. Many areas in the Western United States rely exclusively on ground water as their source of drinking water. Areas that use surface-water resources often need to supplement this supply with ground water. Generally, shallow ground water is susceptible to fluctuating water quality within relatively short time scales and therefore can be used as an indicator of land-use stresses that may, in time, affect deep aquifer systems. This regional study examines data on shallow ground-water quality collected from 1993 to 2004 from 273 agricultural and 181 urban wells from 7 U.S. Geological Survey National Water-Quality Assessment study units in Arizona, California, Nevada, New Mexico, south-central Colorado, and Utah. This report determines important influences that land-use practices may have on the quality of recently recharged ground water, which may ultimately affect deep water supplies within the region. The results of this investigation show that nitrate, the principal species of nitrogen present in ground water, exceeds the U.S. Environmental Protection Agency (USEPA) maximum contaminant level (MCL) of 10 milligrams per liter in water from more than 25 percent of agricultural wells and 10 percent of urban wells. In agricultural areas, the probability of exceeding the USEPA MCL for nitrate is influenced primarily by three factors: fertilizer use, irrigation, and aquifer oxidation-reduction (redox) conditions. At the study-unit level, differences in nutrient concentrations between agricultural and urban land use likely are influenced by ground-water redox conditions within respective aquifer systems. The most commonly detected pesticides belonged to the triazine, urea, amide, and carbamate classes. The triazine herbicides were the predominant pesticides present in both agricultural and urban areas. Simazine and diuron were most frequently detected in shallow ground water within agricultural areas, whereas atrazine, prometon, and tebuthiruon were more commonly detected in urban areas. The carbamate pesticides and the amide, metolachlor, were infrequently detected. Pesticide concentrations in shallow ground water within agricultural or urban land-use settings did not exceed established USEPA MCLs for drinking water. Generally, factors that influenced the detection of pesticides in shallow ground water in the regional area were dissolved oxygen, general soil permeability characteristics, temperature, and depth to screened interval. The most commonly detected volatile organic compounds (VOCs) within urban areas were the trihalomethanes (THMs), solvents, and the fuel oxygenate, methyl tert-butyl-ether (MTBE). The most frequently detected THM was chloroform and the primary detected solvents were tetrachloroethene (PCE) and trichloroethene (TCE). Soil fumigants were detected almost entirely within an agricultural area in the Central Valley of California. The predominant fumigant detected was dibromochloropropane (DBCP), and its occurrence may be a result of its persistence and past use as a soil fumigant. THM concentrations did not exceed the USEPA MCL of 80 micrograms per liter (?g/L) for total THMs in any sample. Two ground-water samples collected within urban areas in Nevada exceeded the USEPA MCL for TCE (5 ?g/L) and the drinking-water advisory for MTBE (20-40 ?g/L). The PCE concentration in one sample from the urban area in Utah and five samples from urban areas within Nevada exceeded the 5 ?g/L MCL. An important factor affecting the detection frequencies of VOCs was the ground-water redox condition. Chloroform and PCE were detected more frequently in well-oxygenated ground water, whereas MTBE was detected more frequently in less-oxygenated water. Multivar

  17. In field study research with poplar trees, Dr. Strand learned that the natural TCE uptake by these plants was too weak to significantly reduce the chemical concentration in the soils. Current research in the

    E-print Network

    Doty, Sharon Lafferty

    ? These are chemical compounds that can cause damage to the central nervous system in humans and other animals by these plants was too weak to significantly reduce the chemical concentration in the soils. Current research in the Strand lab involves the development and testing of trans-genic plants that can increase a plant

  18. Corrigendum to “Feasibility of dibromochloropropane (DBCP) and trichloroethylene (TCE) adsorption onto activated carbons made from nut shells of different almond varieties” [Ind. Crops Prod. 31 (2) (2010) 261-265

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The authors would like to make the following correction in the above mentioned published article. In the Experimental Methods section, the original manuscript described an activation strategy for the pyrolyzed materials that was not accurate. The correct condition for activation was 800C for 45 m...

  19. Mass discharge estimation from contaminated sites: Multi-model solutions for assessment of conceptual uncertainty

    NASA Astrophysics Data System (ADS)

    Thomsen, N. I.; Troldborg, M.; McKnight, U. S.; Binning, P. J.; Bjerg, P. L.

    2012-04-01

    Mass discharge estimates are increasingly being used in the management of contaminated sites. Such estimates have proven useful for supporting decisions related to the prioritization of contaminated sites in a groundwater catchment. Potential management options can be categorised as follows: (1) leave as is, (2) clean up, or (3) further investigation needed. However, mass discharge estimates are often very uncertain, which may hamper the management decisions. If option 1 is incorrectly chosen soil and water quality will decrease, threatening or destroying drinking water resources. The risk of choosing option 2 is to spend money on remediating a site that does not pose a problem. Choosing option 3 will often be safest, but may not be the optimal economic solution. Quantification of the uncertainty in mass discharge estimates can therefore greatly improve the foundation for selecting the appropriate management option. The uncertainty of mass discharge estimates depends greatly on the extent of the site characterization. A good approach for uncertainty estimation will be flexible with respect to the investigation level, and account for both parameter and conceptual model uncertainty. We propose a method for quantifying the uncertainty of dynamic mass discharge estimates from contaminant point sources on the local scale. The method considers both parameter and conceptual uncertainty through a multi-model approach. The multi-model approach evaluates multiple conceptual models for the same site. The different conceptual models consider different source characterizations and hydrogeological descriptions. The idea is to include a set of essentially different conceptual models where each model is believed to be realistic representation of the given site, based on the current level of information. Parameter uncertainty is quantified using Monte Carlo simulations. For each conceptual model we calculate a transient mass discharge estimate with uncertainty bounds resulting from the parametric uncertainty. To quantify the conceptual uncertainty from a given site, we combine the outputs from the different conceptual models using Bayesian model averaging. The weight for each model is obtained by integrating available data and expert knowledge using Bayesian belief networks. The multi-model approach is applied to a contaminated site. At the site a DNAPL (dense non aqueous phase liquid) spill consisting of PCE (perchloroethylene) has contaminated a fractured clay till aquitard overlaying a limestone aquifer. The exact shape and nature of the source is unknown and so is the importance of transport in the fractures. The result of the multi-model approach is a visual representation of the uncertainty of the mass discharge estimates for the site which can be used to support the management options.

  20. Dechlorination of commercial PCBs and other multiple halogenated compounds by a sediment-free culture containing Dehalococcoides and Dehalobacter.

    PubMed

    Wang, Shanquan; He, Jianzhong

    2013-09-17

    At the contaminated sites, polychlorinated biphenyls (PCBs) frequently coexist with other halogenated compounds, such as polybrominated diphenyl ethers (PBDEs), chloroethanes, and chloroethenes. The presence of multiple halogenated compounds usually poses toxicity to dehalogenating microbes, because few cultures are capable of detoxifying a broad spectrum of halogenated compounds. In this study, a sediment-free culture, designed as AD14, is able to sequentially remove halogens from PCBs and other cocontaminants. Culture AD14 dechlorinated the commercial PCB mixture-Aroclor 1260-mainly by removing flanked para- and doubly flanked meta-chlorines. It also dehalogenated octa-brominated diphenyl ether mixture predominantly to tetra-BDEs, 2,4,6-trichlorophenol (2,4,6-TCP) to 4-CP, and tetrachloroethene (PCE)/1,2-dichloroethane (1,2-DCA) completely to ethene. When applied to a mixture of the above-mentioned compounds, culture AD14 stepwise removed halogens from 2,4,6-TCP, 1,2-DCA, PCE, PBDEs, and PCBs. Illumina sequencing analysis of 16S rRNA genes showed that only two known dechlorinating genera, Dehalococcoides and Dehalobacter, were present in culture AD14. Quantitative real-time PCR analysis showed that the 16S rRNA gene copies of Dehalococcoides and Dehalobacter increased from 1.14 × 10(5) to 7.04 × 10(6) copies mL(-1) and from 1.15 × 10(5) to 8.20 × 10(6) copies mL(-1) after removing 41.13 ?M of total chlorine from PCBs. The above results suggest that both Dehalobacter and Dehalococcoides could be responsible for PCB dechlorination. Although two Dehalococoides mccartyi strains with identical 16S rRNA genes were isolated from the PCBs-dechlorinating mixed culture using trichloroethene (TCE) and vinyl chloride (VC) as alternatives to PCBs, the two isolates are incapable of dechlorinating PCBs. In all, culture AD14 is promising for bioremediation applications at sites cocontaminated with PCBs and other halogenated compounds. PMID:23964900

  1. Measurement and deduction of emissions of trichloroethene, tetrachloroethene, and trichloromethane (chloroform) in the northeastern United States and southeastern Canada

    NASA Astrophysics Data System (ADS)

    Kleiman, G.; Prinn, R. G.

    2000-12-01

    We present optimal estimates of the emission patterns for trichloroethene (TCE, CHCl = CCl2), tetrachloroethene (perchloroethylene, CCl2 = CCl2), and trichloromethane (chloroform, CHCl3) utilizing hourly gas chromatographie measurements at Nahant, Massachusetts (approximately 10 km northeast of Boston). Our analysis combines the measurements with back trajectory information obtained from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT-4) model (National Oceanic and Atmospheric Administration Air Resources Laboratory, Silver Spring, Maryland). Using a Kaiman filter inverse method and an analytical solution of the continuity equation to estimate the effects of eddy diffusion, we calculate the surface emissions on a 1°×1° grid for the selected species necessary to optimally match the observations. These emissions are compared with the estimates determined by the Reactive Chlorine Emissions Inventory (RCEI) working group of the International Global Atmospheric Chemistry Program Global Emissions Inventory Activity (GEIA). The new emissions scenarios computed here provide an observation-based assessment for comparison with the RCEI emissions inventories for the northeastern United States and southeastern Canada. Results indicate that the RCEI estimates of the anthropogenic emissions of these chemicals in the geographical domain studied differ from our optimal estimates but generally lie within the estimated error of these optimal estimates. Results are sensitive to the assumed vertical distributions and hence to the assumed vertical mixing rates. The current accuracy achievable through this observation-based technique (±45%) is limited in large part by the uncertainty in the vertical distribution of these compounds in the troposphere over highly emitting regions. Within this accuracy the optimal estimates of emissions presented here indicate that the emissions for many grid cells do not need to be corrected significantly from the 1990 estimates presented in the RCEI. However, for trichloroethene and tetrachloroethene we calculate large statistically significant decreases in emissions for some highly populated urban locations on the East Coast and correspondingly large increases for some less populous grid cells in Pennsylvania and New York State. Only anthropogenic sources of trichloromethane (representing roughly 11% of estimated global emissions) were gridded in the RCEI inventory and included in the initial inventory used here. We find that these anthropogenic emissions are, as expected, too low to explain the observations and that most grid cells require small increases and several cells require substantial increases (˜5-10 nmoles m-2 h-1) to produce emissions estimates that are consistent with observations. This is reasonable given current knowledge of natural land sources (e.g., soil emissions) and a large oceanic source for this compound inferred from previous oceanic observations.

  2. Middlesex FUSRAP Site - A Path to Site-Wide Closure - 13416

    SciTech Connect

    Miller, David M.; Edge, Helen

    2013-07-01

    The road-map to obtaining closure of the Middlesex Sampling Plant FUSRAP site in Middlesex, New Jersey (NJ) has required a multi-faceted approach, following the CERCLA Process. Since 1998, the US ACE, ECC, and other contractors have completed much of the work required for regulatory acceptance of site closure with unrestricted use. To date, three buildings have been decontaminated, demolished, and disposed of. Two interim storage piles have been removed and disposed of, followed by the additional removal and disposal of over 87,000 tons of radiologically and chemically-impacted subsurface soils by the summer of 2008. The US ACE received a determination from the EPA for the soils Operable Unit, (OU)-1, in September 2010 that the remedial excavations were acceptable, and meet the criteria for unrestricted use as required by the 2004 Record of Decision (ROD) for OU-1. Following the completion of OU-1, the project delivery team performed additional field investigation of the final Operable Unit for Middlesex, OU-2, Groundwater. As of December 2012, the project delivery team has completed a Supplemental Remedial Investigation, which will be followed with a streamlined Feasibility Study, Proposed Plan, and ROD. Several years of historical groundwater data was available from previous investigations and the FUSRAP Environmental Surveillance Program. Historical data indicated sporadic detections of Volatile Organic Compounds (VOCs), primarily trichloroethylene (TCE), carbon tetrachloride (CT), and methyl tert-butyl ether (MTBE), with no apparent trend or pattern indicating extent or source of the VOC impact. In 2008, the project delivery team initiated efforts to re-assess the Conceptual Site Model (CSM) for groundwater. The bedrock was re-evaluated as a leaky multi-unit aquifer, and a plan was developed for additional investigations for adequate bedrock characterization and delineation of groundwater contaminated primarily by CT, TCE, and tetrachloroethene (PCE). The investigation was designed to accumulate multiple lines of evidence to determine the source and to delineate the extent of contamination, as required to complete the CERCLA Process and gain regulatory acceptance. Investigative techniques included in-well vertical flow tracing, borehole geophysics and packer testing of temporary test holes to characterize contamination in the bedrock fractures beneath the site, and to delineate likely source areas. (authors)

  3. Semi-passive, Chemical Oxidation Schemes for the Long-term Treatment of Contaminants

    SciTech Connect

    Frank W. Schwartz

    2005-12-13

    This research involves a combined experimental and modeling study that builds on our previous DOE-sponsored work in investigating how KMnO{sub 4} can be better used with in situ remediation of groundwater contaminated by chlorinated ethylenes (e.g., PCE, TCE, DCE). This study aims to provide scientific basis for developing a new long-term, semi-passive ISCO scheme that uses controlled release KMnO{sub 4} as a reactive barrier component. Specific objectives of the study are (1) to construct controlled release KMnO{sub 4} as a new reactive barrier component that could deliver permanganate at a controlled rate over long time periods of years, (2) to quantitatively describe release mechanisms associated with the controlled release KMnO{sub 4}, (3) to demonstrate efficacy of the new remediation scheme using proof-of-concept experiments, and (4) to design advanced forms of controlled release systems through numerical optimization. The new scheme operates in a long-term, semi-passive manner to control spreading of a dissolved contaminant plume with periodic replacement of the controlled release KMnO{sub 4} installed in the subsurface. As a first step in developing this remedial concept, we manufactured various prototype controlled release KMnO{sub 4} forms. Then we demonstrated using column experiments that the controlled release KMnO{sub 4} could deliver small amount of permanganate into flowing water at controlled rates over long time periods of years. An analytical model was also used to estimate the diffusivities and durations of the controlled release KMnO{sub 4}. Finally, proof-of-concept flow-tank experiments were performed to demonstrate the efficacy of the controlled release KMnO{sub 4} scheme in controlling dissolved TCE plume in a long-term, semi-passive manner. Another important thrust of our research effort involved numerical optimization of controlled release systems. This study used a numerical model that is capable of describing release patterns of active agent from controlled release systems of varied forms and applications. We manufactured prototype single- and double-layered matrix-type controlled release systems and tested their release patterns using numerical simulations and column experiments. In a series of simulations, we demonstrated that an encapsulated, dispersed-agent polymeric matrix-type controlled release system could deliver active agent at a predetermined constant rate for long time periods of years and decades. Such long-term, constant release system is useful in the construction of fertilizers, herbicides, or implantable drug delivery devices as well as in subsurface treatment. Construction of more advanced forms of controlled release systems is currently under way.

  4. Slow Release of Permanganate from Injectable Fumed Silica Gel: Rheological Properties and Release Dynamics

    NASA Astrophysics Data System (ADS)

    Yang, S.; Zhong, L.; Oostrom, M.; Li, G.

    2014-12-01

    ISCO (In Situ Chemical Oxidation) has been proved to be a useful remediation technology in destroying most prevalent aqueous organic contaminants. For permanganate (MnO4-) in particular, the chemistry of degradative oxidation is well established for cleaning up groundwater containing trichloroethene (TCE) and tetrachloroethene (PCE). However the long-term effectiveness of the application of this oxidant has been questioned due to the observed post remediation rebound of contaminant concentrations. To improve the efficiency of ISCO using MnO4-under specific site conditions, the technology of emplacing slow-releasing permanganate in an aquifer has been studied. We have developed an injectable slow-release permanganate slurry/gel (ISRPG) by mixing KMnO4 with fumed silica in water. Ideally, the slurry/gel forms would release low concentration of MnO4- by diffusion to maintain a desired concentration level of the agent within the chemically active zone. We have investigated the properties and tested the application of this ISRPG in laboratory studies. Rheological study indicated ISRPG has high viscosity and shear thinning property. The viscosity of silica gel could be lowered by mechanical mixing thus making it easy for subsurface injection. Batch tests revealed that MnO4- was diffused from ISRPG and the gel did not disperse but maintained its initial shape. In column experiments we showed that permanganate release covered 6 times more effluent pore volumes when ISRPG was injected compared to MnO4- solution injection. We also observed TCE degradation by released MnO4-, and the remedial performance occurred over a much longer timeframe with ISRPG compared to MnO4- solution injection. In 2-D flow cell tests we demonstrated that water flows around the injected gel, carrying MnO4- diffused out from the gel and forming a downstream oxidant plume, while the gel was stationary. ISRPG slowly released low concentrations of permanganate to maintain a predetermined level of the agent within the chemically active zone.

  5. Jul Aug Nov DecSep Oct Jan Feb May JunMar Apr Foundations

    E-print Network

    Mootha, Vamsi K.

    Experiences & Scholarly Project Transition to the PCE PCE Essentials Homeostasis 1 Homeostasis 2 MBBD Pathways/Population Health Homeostasis 1: CV, Resp, Heme Homeostasis 2: Renal, GI, Endo, Repro Mind, Brain, Behavior

  6. REDUCTIVE BIOTRANSFORMATION OF TETRACHLOROETHENE TO ETHENE DURING ANAEROBIC DEGRADATION OF TOLUENE: EXPERIMENTAL EVIDENCE AND KINETICS

    EPA Science Inventory

    Reductive biotransformation of tetrachloroethene (PCE) to ethene occurred during anaerobic degradation of toluene in an enrichment culture. Ethene was detected as a dominant daughter product of PCE dechlorination with negligible accumulation of other partially chlorinated ethenes...

  7. HAZARDOUS AIR POLLUTANTS: DRY-DEPOSITION PHENOMENA

    EPA Science Inventory

    Dry-deposition rates were evaluated for two hazardous organic air pollutants, nitrobenzene and perchloroethylene, to determine their potential for removal from the atmosphere to three building material surfaces, cement, tar paper, and vinyl asbestos tile. Dry-deposition experimen...

  8. GTE_PEMTB_P3B Parameters 17

    Atmospheric Science Data Center

    2013-02-19

    ... NMHC/Halocarbons/Alkyl Nitrates: Methyl Chloride F-12 F-114 F-11 HCFC-141B HCFC-134a HCFC-22 ... 2,3,4-trimethylpethane Methylene Chloride Chloroform Perchloroethylene HFC-134A HCFC22 HCFC142B ...

  9. GTE_PEMTB_DC8 Parameters 15

    Atmospheric Science Data Center

    2013-02-19

    ... NMHC/Halocarbons/Alkyl Nitrates: Methyl Chloride F-12 F-114 F-11 HCFC-141B HCFC-134a HCFC-22 ... 2,3,4-trimethylpethane Methylene Chloride Chloroform Perchloroethylene HFC-134A HCFC22 HCFC142B ...

  10. SPATIAL AND SOURCE TYPE DISTRIBUTION OF EMISSIONS OF SELECTED TOXIC VOLATILE ORGANIC COMPOUNDS IN THE UNITED STATES IN 1990

    EPA Science Inventory

    The annual anthropogenic emission, principal contributing source types, and spatial distributions for selected toxic volatile organic compounds (VOCS) are presented for the United States. oxic compounds addressed include acrylonitrile, benzene, perchloroethylene, and trichloroeth...

  11. 40 CFR 63.99 - Delegated Federal authorities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...General Provisions 1 XDEarly Reductions...Coke Oven BatteriesM Perc Dry Cleaning...General ProvisionsXD. Early Reductions...Oven Batteries XM. Perchloroethylene...General ProvisionsX DEarly Reductions...Oven...

  12. 77 FR 75447 - Notice of Lodging of Proposed Consent Judgment Under the Resource Conservation and Recovery Act...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-20

    ...violated these regulations in connection with the management at its facility of waste perchloroethylene, used fluorescent light bulbs, and the associated recordkeeping requirements. The Consent Judgment provides for KTN to implement injunctive...

  13. TRICHLOROETHYLENE IHIBITS VOLTAGE-SENSITIVE CALCIUM CURRENTS IN DIFFERENTIATED PC 12 CELLS.

    EPA Science Inventory

    ABSTRACT BODY: It has been demonstrated recently that volatile organic compounds (VOCs)such as toluene, perchloroethylene and trichloroethylene inhibit function of voltage-sensitive calcium channels (VSSC). Such actions are hypothesized to contribute to the acute neurotoxicity of...

  14. EFFECTS OF INHALATION OF ORGANIC CHEMICAL AIR CONTAMINANTS ON MURINE LUNG HOST DEFENSES

    EPA Science Inventory

    The potential health hazards of exposure to threshold limit value (TLV) concentrations of acetaldehyde, acrolein, propylene oxide, chloroform, methyl chloroform, carbon tetrachloride, allyl chloride, methylene chloride, ethylene trichloride, perchloroethylene, benzene, phenol, mo...

  15. EXTRACTION AND QUANTITATIVE ANALYSIS OF ELEMENTAL SULFUR FROM SULFIDE MINERAL SURFACES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY. (R826189)

    EPA Science Inventory

    A simple method for the quantitative determination of elemental sulfur on oxidized sulfide minerals is described. Extraction of elemental sulfur in perchloroethylene and subsequent analysis with high-performance liquid chromatography were used to ascertain the total elemental ...

  16. 40 CFR 63.324 - Reporting and recordkeeping requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Perchloroethylene Air Emission Standards for Dry Cleaning Facilities § 63.324 Reporting...a) Each owner or operator of a dry cleaning facility shall notify the Administrator...that is, physical location) of the dry cleaning facility; (3) A brief...

  17. 40 CFR 63.324 - Reporting and recordkeeping requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Perchloroethylene Air Emission Standards for Dry Cleaning Facilities § 63.324 Reporting...a) Each owner or operator of a dry cleaning facility shall notify the Administrator...that is, physical location) of the dry cleaning facility; (3) A brief...

  18. 40 CFR 63.322 - Standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Perchloroethylene Air Emission Standards for Dry Cleaning Facilities § 63.322 Standards...owner or operator of each existing dry cleaning system and of each new transfer...gas-vapor stream contained within each dry cleaning machine through a refrigerated...

  19. 40 CFR 63.322 - Standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Perchloroethylene Air Emission Standards for Dry Cleaning Facilities § 63.322 Standards...owner or operator of each existing dry cleaning system and of each new transfer...gas-vapor stream contained within each dry cleaning machine through a refrigerated...

  20. 40 CFR 63.322 - Standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Perchloroethylene Air Emission Standards for Dry Cleaning Facilities § 63.322 Standards...owner or operator of each existing dry cleaning system and of each new transfer...gas-vapor stream contained within each dry cleaning machine through a refrigerated...