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1

The photodissociation dynamics of tetrachloroethylene  

SciTech Connect

We present a direct current slice imaging study of tetrachloroethylene (C{sub 2}Cl{sub 4}) photodissociation, probing the resulting ground state Cl ({sup 2}P{sub 3/2}) and spin-orbit excited state Cl* ({sup 2}P{sub 1/2}) products. We report photofragment images, total translational energy distributions and the product branching ratio of Cl*/Cl following dissociation at 235 and 202 nm, obtained using a two-color reduced-Doppler dissociation/probe. Near 235 nm, the Cl translational energy distribution shows a peak at the limit of the available energy, indicating a direct dissociation through a {sigma}*(C-Cl) (leftarrow){pi} (C=C) transition, which is superimposed on a broader underlying distribution. The ground state Cl image and associated translational energy distribution at 202 nm is broad and peaked at lower energy, suggesting either internal conversion to the ground state or a lower excited state prior to dissociation. The Cl* images are similarly broad at both wavelengths. The branching ratio is presented as a function of recoil energy, but after integration shows a near-statistical average of Cl:Cl* as 70:30 at both wavelengths. All the images are largely isotropic, with anisotropy parameters ({beta}) of 0.05 {+-} 0.03.

Herath, Nuradhika; Hause, Michael L.; Suits, Arthur G. [Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States)

2011-04-28

2

Tetrachloroethylene Emissions and Exposure in Dry Cleaning  

Microsoft Academic Search

Tetrachloroethylene (PCE) emissions and the exposure of workers in six commercial and three industrial dry-cleaning establishments that use dry-to-dry machines were determined. The personal samples and area samples [8-hr time-weighted average (TWA) and short-term exposure] were collected with charcoal tubes and passive monitors. The temporal variation of PCE concentration in the workplace air was monitored using a Fourier transform infrared

J. Räisänen; R. Niemelä; C. Rosenberg

2001-01-01

3

Leaching of tetrachloroethylene from vinyl-lined pipe  

Microsoft Academic Search

Tetrachloroethylene has been used in the manufacture of vinyl-lined asbestos cement pipe installed in water distribution systems in certain New England communities. Tetrachloroethylene was used as a solvent for Piccotex, a vinyl-toluene ..cap alpha..-methyl styrene co-polymer, which was then sprayed on the interior of the finished asbestos cement pipe. The migration of tetrachloroethylene through the vinyl lining was modeled as

Avery H. Demond

1985-01-01

4

A freshwater anaerobe coupling acetate oxidation to tetrachloroethylene dehalogenation.  

PubMed Central

Strain TT4B has been isolated from anaerobic sediments known to be contaminated with a variety of organic solvents. It is a gram-negative, rod-shaped bacterium and grew anaerobically with acetate as the electron donor and tetrachloroethylene as the electron acceptor in a mineral medium. cis-Dichloroethylene was the halogenated product. This strain did not grow fermentatively and used only acetate or pyruvate as electron donors. Tetrachloroethylene and trichloroethylene were used as electron acceptors, as were ferric nitriloacetate and fumarate. Nitrogen and sulfur oxyanions were not able to substitute as the electron acceptor for this organism. Modest growth occurred in a two-phase system with 1 ml of hexadecane containing 50 to 200 mM tetrachloroethylene (aqueous concentrations, 25 to 100 microM) and 10 ml of anaerobic mineral solution with Na2S as the reducing agent. Growth was completely inhibited at tetrachloroethylene levels above 100 microM.

Krumholz, L R; Sharp, R; Fishbain, S S

1996-01-01

5

Atmospheric oxidation of tetrachloroethylene: an ab initio study.  

PubMed

A number of experimental studies have been conducted to determine the atmospheric oxidation of tetrachloroethylene, many indicating phosgene as the major product. Although various mechanisms have been suggested, the mechanism of phosgene production is unclear. Additionally, confusion has arisen over the role chlorine atoms may play in the oxidation of tetrachloroethylene and the products produced. To clarify these points, this study presents a comprehensive computational study of both the hydroxyl radical and the chlorine atom initiated atmospheric oxidation mechanism of tetrachloroethylene. The energetics for the oxidation of tetrachloroethylene (C(2)Cl(4)) are computed using ab initio methods. Potential energy surfaces of the reaction pathways are determined from the computations. This study clarifies the involvement of the Cl-initiated reaction pathways in the oxidation of tetrachloroethylene. Results from this work suggest that the final products are primarily from the Cl-initiated oxidation and include: trichloroacetyl chloride [ClC(O)CCl(3)], phosgene [C(O)Cl(2)], and regeneration of the initiating chlorine atom. PMID:20669984

Christiansen, Carrie J; Francisco, Joseph S

2010-09-01

6

SURFACTANT ENHANCED REMEDIATION OF SOIL COLUMNS CONTAMINATED BY RESIDUAL TETRACHLOROETHYLENE  

EPA Science Inventory

The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa and was evaluated in four column experiments. esidual PCE was emplaced by injecting 14 C-labeled PCE into water-saturated soil columns and displacing the free product with water. ...

7

The effect of sulfide on the reductive dehalogenation of tetrachloroethylene  

Microsoft Academic Search

One of the potential variables that appears to play a major role in the development and dehalogenation ability of bacterial cultures is the external reductant employed in the research to reduce the liquid anaerobic medium. In this research, the effect of the addition of the external reductant, sodium sulfide, on the reductive dehalogenation of tetrachloroethylene was examined. Variations in dehalogenation,

Robert Watson Holden

1999-01-01

8

UPDATED CARCINOGENICITY ASSESSMENT FOR TETRACHLOROETHYLENE (PERCHLOROETHYLENE, PERC, PCE): ADDENDUM TO THE HEALTH ASSESSMENT DOCUMENT FOR TETRACHLOROETHYLENE (PERCHLOROETHYLENE). EXTERNAL REVIEW DRAFT  

EPA Science Inventory

The Office of Health and Environmental Assessment has prepared the addendum to serve as a source document for EPA use. The addendum updates EPA's July 1985 Health Assessment Document for Tetrachloroethylene (Perchloroethylene, PERC, PCE) by providing a review of the findings of t...

9

NIOSH (National Institute for Occupational Safety and Health) Criteria for a Recommended Standard: Occupational Exposure to Tetrachloroethylene (Perchloroethylene).  

National Technical Information Service (NTIS)

The report provides relevant data concerning the exposure of humans to tetrachloroethylene within the workplace. Recommendations for a tetrachloroethylene standard are provided based on analysis of data. The document covers the workplace environment, medi...

1976-01-01

10

Systematic Literature Review of Uses and Levels of Occupational Exposure to Tetrachloroethylene  

Microsoft Academic Search

Tetrachloroethylene has been one of the most widely used chlorinated solvents in the United States. This review provides a basis for tetrachloroethylene exposure assessment in population-based case-control studies. We performed literature searches in MEDLINE, TOXLINE, NIOSHTIC, and the NIOSH Health Hazard Evaluation databases using relevant search terms. We calculated weighted arithmetic means from the measurement data and compiled these into

Laura S. Gold; Anneclaire J. De Roos; Martha Waters; Patricia Stewart

2008-01-01

11

Early Lifestage Exposure and Potential Developmental Susceptibility to Tetrachloroethylene [Journal Article  

EPA Science Inventory

Tetrachloroethylene, also known as perchloroethylene or "perc", is a highly volatile and lipophilic solvent widely used in dry cleaning, textile processing, and metal-cleaning operations. The limited epidemiological and toxicological data available for developmental lifestage ex...

12

Tetrachloroethylene leached from lined asbestos-cement pipe into drinking water [with Discussion  

Microsoft Academic Search

Tetrachloroethylene has been detected in concentrations ranging from a few micrograms per litre to several milligrams per litre in dead ends of water distribution systems made of vinyl-toluene-lined asbestos-cement pipe. About 1600 km (1000 mi) of this lined pipe is being used, primarily in New England. Tetrachloroethylene concentrations can be lessened by flushing and installing continuous bleeders, two of the

Charles D. Larson; O. Thomas Love Jr.; Gardiner Reynolds III; S. Wyatt McCallie; R. H. Moser; Edward J. Calabrese

1983-01-01

13

Linking indoor air and pharmacokinetic models to assess tetrachloroethylene risk  

SciTech Connect

Physiologically based pharmacokinetic (PBPK) models describing the uptake, metabolism, and excretion of xenobiotic compounds are now proposed for use in regulatory health-risk assessments. In this study the authors investigate the extent of PCE metabolism arising from domestic respiratory exposure to tetrachloroethylene (PCE) from ground water, as predicted using a PBPK model. Indoor exposure patterns they use as input to the PBPK model are realistic ones generated from a three-compartment model describing volatilization of PCE from domestic water into household air. Values they use for the metabolic parameters of the PBPK model are estimated from data on urinary metabolites in workers exposed to PCE. It is shown that for respiratory PCE exposure due to typical levels of PCE in ground water, use of time-weighted average air concentrations with a steady-state PBPK model yields estimates of total metabolized PCE similar to those obtained using completely dynamic modeling, despite considerable uncertainty in key exposure- and metabolic-model parameters. These findings suggest that, for PCE, risk estimation taking pharmacokinetics into account may be accomplished using a simple analytic approach.

Bogen, K.T.; McKone, T.E.

1988-12-01

14

Indoor tetrachloroethylene levels and determinants in Paris dwellings.  

PubMed

There is growing public health concern about indoor air quality. Tetrachloroethylene (PERC), a chlorinated volatile organic compound widely used as a solvent in dry cleaning facilities, can be a residential indoor air pollutant. As part of an environmental investigation included in the PARIS (Pollution and asthma Risk: an Infant Study) birth cohort, this study firstly aimed to document domestic PERC levels, and then to identify the factors influencing these levels using standardized questionnaires about housing characteristics and living conditions. Air samples were collected in the child's bedroom over one week using passive devices when infants were 1, 6, 9, and 12 months. PERC was identified and quantified by gas chromatography/mass spectrometry. PERC annual domestic level was calculated by averaging seasonal levels. PERC was omnipresent indoors, annual levels ranged from 0.6 to 124.2 ?g/m3. Multivariate linear and logistic regression models showed that proximity to dry cleaning facilities, do-it-yourself activities (e.g.: photographic development, silverware), presence of air vents, and building construction date (<1945) were responsible for higher domestic levels of PERC. This study, conducted in an urban context, provides helpful information on PERC contamination in dwellings, and identifies parameters influencing this contamination. PMID:23127492

Roda, Célina; Kousignian, Isabelle; Ramond, Anna; Momas, Isabelle

2012-11-03

15

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

Microsoft Academic Search

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.;\\u000a;\\u000aThree 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

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

2003-01-01

16

Cosolvent effects of alcohols on the Henry's law constant and aqueous solubility of tetrachloroethylene (PCE)  

Microsoft Academic Search

The effects of selected cosolvents ethyl alcohol (EtOH), isopropyl alcohol (IPA), and tertbutyl alcohol (TBA) on the Henry's law constant (H) of tetrachloroethylene (PCE) in aqueous solutions were investigated using the static headspace method. Alcohols in solution at a concentration around 20% and above acted as cosolvents increasing the aqueous solubility of PCE, which resulted in lower H values for

Tarek I Ladaa; Cindy M Lee; John T Coates; Ronald W Falta

2001-01-01

17

The Removal of Tri (TCE) and Tetrachloroethylene (PCE) from Aqueous Solution using High Energy Electrons  

Microsoft Academic Search

Trichloroethylene (TCE) and tetrachloroethylene (PCE) are common groundwater contaminants that persist inithe environment. An innovative treatment process employing high energy electron beam irradiation has been shown to be an effective process for treating TCE- or PCE-contaminated water, wastewater, and water containing suspended solids.Experiments conducted at the Electron Beam Research Facility, Miami, Florida, have led to a better understanding of the

William J. Cooper; David E. Meacham; Michael G. Nickelsen; Kaijun Lin; David B. Ford; Charles N. Kuruczand; Thomas D. Waite

1993-01-01

18

Continuous Determination of High-Vapor Phase Concentrations of Tetrachloroethylene Using On-Line Mass Spectrometry  

EPA Science Inventory

A method was developed to determine the vapor concentration of tetrachloroethylene (PCE) at and below its equilibrium vapor phase concentration, 168,000 Ī¼g/L (25Ā°C). Vapor samples were drawn by vacuum into a six-port sampling valve and injected through a jet separator into an io...

19

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...

20

Euro Chlor Risk Assessment for the Marine Environment Osparcom Region: North Sea - Tetrachloroethylene  

Microsoft Academic Search

This risk assessment on tetrachloroethylene (PER) was carried out specifically for the marine environment, according to the methodology laid down in the EU risk assessment Regulation (1488\\/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs

Christ De Rooij; Jean Charles Boutonnet; Veronique Garny; Andre Lecloux; Roger Papp; Roy S Thompson; Dolf Van Wijk

1998-01-01

21

Spontaneous abortions and congenital malformations among women exposed to tetrachloroethylene in dry cleaning  

Microsoft Academic Search

STUDY OBJECTIVE: The aim of the study was to determine whether exposure to tetrachloroethylene during the first trimester of pregnancy has harmful effects on pregnancy outcome. DESIGN: The study used record linkage identification of cases and case-control comparison. SETTING: The study involved dry cleaner and laundry workers throughout Finland who had become pregnant during the study period. Controls were age

P. Kyyroenen; H. Taskinen; M. L. Lindbohm; K Hemminki; O P Heinonen

1989-01-01

22

Aerobic degradation of tetrachloroethylene by toluene-o-xylene monooxygenase of Pseudomonas stutzeri OX1  

Microsoft Academic Search

Tetrachloroethylene (PCE) is thought to have no natural source, so it is one of the most difficult contaminants to degrade biologically. This common groundwater pollutant was thought completely nonbiodegradable in the presence of oxygen. Here we report that the wastewater bacterium Pseudomonas stutzeri OX1 degrades aerobically 0.56 ?mol of 2.0 ?mol PCE in 21 h (Vmax ? 2.5 nmol min?1

Doohyun Ryoo; Hojae Shim; Paola Barbieri; Thomas K. Wood

2000-01-01

23

Study of restacked single molecular layer molybdenum disulfide with organic tetrachloroethylene included  

Microsoft Academic Search

The structure of restacked monomolecular layers of MoS2 with organic tetrachloroethylene (TCE) included was studied using X-ray powder diffraction and X-ray diffraction of thin films in reflection and transmission. It was found that the MoS2 host layers are turbostratically stacked, separated by a monolayer of TCE and that the MoS2 is strongly distorted, with the Mo in an octahedral coordination.

X. Zhou; D. Yang; R. F. Frindt

1996-01-01

24

Effects of Tetrachloroethylene on the Viability and Development of Embryos of the Japanese Medaka, Oryzias latipes  

Microsoft Academic Search

We evaluated the acute toxicity of Tetrachloroethylene (C2Cl4), and investigated its sub-chronic effects on the embryonic development of Japanese medaka (Oryzias latipes). One-day-old eggs\\/embryos of this fish species were exposed, under static renewal conditions, to serial concentrations (0,\\u000a 20, 40, 60, and 80 mg\\/L) of C2Cl4 for 96 h (acute) and 10 days (sub-chronic) time periods. The toxic endpoints evaluated

H. B. Spencer; W. R. Hussein; P. B. Tchounwou

2002-01-01

25

Exposure to Tetrachloroethylene-Contaminated Drinking Water and the Risk of Pregnancy Loss  

Microsoft Academic Search

There is little information on the impact of solvent-contaminated drinking water on pregnancy outcomes. This retrospective\\u000a cohort study examined whether maternal exposure to tetrachloroethylene (PCE)-contaminated drinking water in the Cape Cod region\\u000a of Massachusetts influenced the risk of clinically recognized pregnancy loss. The study identified exposed (n=959) and unexposed (1,087) women who completed a questionnaire on their residential and pregnancy

Ann Aschengrau; Janice M. Weinberg; Lisa G. Gallagher; Michael R. Winter; Veronica M. Vieira; Thomas F. Webster; David M. Ozonoff

2009-01-01

26

Spontaneous abortions and congenital malformations among women exposed to tetrachloroethylene in dry cleaning.  

PubMed Central

STUDY OBJECTIVE: The aim of the study was to determine whether exposure to tetrachloroethylene during the first trimester of pregnancy has harmful effects on pregnancy outcome. DESIGN: The study used record linkage identification of cases and case-control comparison. SETTING: The study involved dry cleaner and laundry workers throughout Finland who had become pregnant during the study period. Controls were age matched but otherwise unselected women giving birth to normal babies in the study period. SUBJECTS: Cases were defined as women who had been treated for spontaneous abortion or had delivered a malformed child. Out of 5700 workers nearly half had been pregnant during the study period. One pregnancy only was randomly selected for study per worker, and the final study population was 247 women with spontaneous abortions and 33 with malformed infants. Three age matched controls were selected for each abortion case and five for each malformation case. MEASUREMENTS AND MAIN RESULTS: Three women out of four had worked in early pregnancy. Exposure information was collected from 1108 women by mailed questionnaires, with a 77% response, and was partly confirmed by biological monitoring data. Exposure to tetrachloroethylene was found to be significantly associated with spontaneous abortions (odds ratio 3.6, p less than 0.05). CONCLUSION: The findings, together with other available data, indicate that exposure of pregnant women to tetrachloroethylene needs to be minimised.

Kyyronen, P; Taskinen, H; Lindbohm, M L; Hemminki, K; Heinonen, O P

1989-01-01

27

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

SciTech Connect

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.

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

1986-07-01

28

PBPK modeling of the metabolic interactions of carbon tetrachloride and tetrachloroethylene in B6C3F1 mice  

Microsoft Academic Search

Potential exists for widespread human exposure to low levels of carbon tetrachloride (CT) and tetrachloroethylene (TET). These halocarbons are metabolized by the cytochrome P450 system. CT is known to inhibit its own metabolism (suicide inhibition) and to cause liver injury by generation of metabolically derived free radicals. The objective of this research was to use develop a physiologically based pharmacokinetic

J Fisher; M Lumpkin; J Boyd; D Mahle; J. V Bruckner; H. A El-Masri

2004-01-01

29

Simulation calculations of tetrachloroethylene decomposition in air mixtures under electron beam irradiation  

NASA Astrophysics Data System (ADS)

Theoretical simulation calculations of tetrachloroethylene (PCE) decomposition in air mixtures under electron beam (EB) irradiation have been carried out based on the experimental results. A computer code Kinetic and a Gear method were used and 324 reactions and 76 species were considered. From calculated results, we learn that more than 99% PCE is decomposed at 4.4 kGy dose when the initial concentration of PCE is 322 ppm; concentrations of inorganic carbons (CO+CO2) increases with the dose, and the relative carbon concentration of inorganic carbons is about 17% at 13.1 kGy; phosgene (COCl2) and trichloroacetyl chloride (CCl3COCl) are predicted as main organic products and are confirmed by the experimental results. The good agreement is obtained between the calculated results and the experimental data.

Sun, Y.; Chmielewski, A. G.; Bu?ka, S.; Zimek, Z.; Nichipor, H.

2009-07-01

30

Development of Binary Liquid-Vapor Phase Diagram Laboratory Procedures to Replace the Traditional Tetrachloroethylene\\/Cyclohexanone System  

Microsoft Academic Search

Two chemical systems were investigated and implemented as alternatives to the traditional tetrachloroethylene\\/cyclohexanone system used in the binary liquid-vapor phase diagram physical chemistry laboratory. Both the 2-butanone\\/cyclohexane and the ethyl acetate\\/cyclohexane systems reduce the cost of waste disposal and eliminate the use of chlorinated solvents. Student data showed that the azeotropic composition and temperature could be easily identified from a

Kelly J. Gordon; Laura Kenkel; Stephanie Prescia; Marcy Towns

31

A field experiment to study the behavior of tetrachloroethylene below the water table: Spatial distribution of residual and pooled DNAPL  

Microsoft Academic Search

This paper describes a field experiment involving the release of 230.9 liters of tetrachloroethylene (PCE) below the water table in a naturally occurring, unconfined sand aquifer. The release was executed in a 3m [times] 3m [times] 3.4m deep, sealable-joint steel sheet-pile cell anchored into an underlying clay aquitard. After allowing 28 days for redistribution, excavation of the upper approximately 0.9

B. H. Kueper; M. Mah; D. Redman; R. C. Starr; S. Reitsma

2009-01-01

32

Urinary excretion of total trichloro-compounds, trichloroethanol, and trichloroacetic acid as a measure of exposure to trichloroethylene and tetrachloroethylene  

PubMed Central

Ikeda, M., Ohtsuji, H., Imamura, T., and Komoike, Y. (1972).Brit. J. industr. Med.,29, 328-333. Urinary excretion of total trichloro-compounds, trichloroethanol, and trichloroacetic acid as a measure of exposure to trichloroethylene and tetrachloroethylene. To investigate the relation between trichloroethylene and tetrachloroethylene concentrations in working environments and metabolite concentrations in urine, a series of surveys was conducted at 17 workshops where the vapour concentration in the air of each workshop was relatively constant. Urine samples collected from 85 male workers were analysed for total trichloro-compounds (TTC), and trichloroacetic acid (TCA). Trichloroethanol (TCE) was estimated by difference. Statistical analyses of the data revealed that the urinary concentrations of both TTC and TCE were proportional to the atmospheric concentration of trichloroethylene. The concentration of TCA was also related to the vapour concentration up to 50 p.p.m. but not at higher concentrations. Further calculations suggested that only one-third of the trichloroethylene absorbed through the lungs was excreted in the urine during working time. In tetrachloroethylene exposure, urinary metabolite levels increased until the atmospheric concentration of the solvent reached 50 to 100 p.p.m., but little increase occurred at higher concentration. This observation was further confirmed by experimental exposure of rats. The toxicological significance of changes in the metabolism of the two solvents is discussed in relation to the possible necessity of reducing the threshold limit value from the current value of 100 p.p.m.

Ikeda, Masayuki; Ohtsuji, Hatsue; Imamura, Toshiko; Komoike, Yoshihiko

1972-01-01

33

THE EFFECT OF LOW CONCENTRATIONS OF TETRACHLOROETHYLENE ON THE PERFORMANCE OF PEM FUEL CELLS  

SciTech Connect

Polymer electrolyte membrane (PEM) fuel cells use components that are susceptible to contaminants in the fuel stream. To ensure fuel quality, standards are being set to regulate the amount of impurities allowable in fuel. The present study investigates the effect of chlorinated impurities on fuel cell systems using tetrachloroethylene (PCE) as a model compound for cleaning and degreasing agents. Concentrations between 0.05 parts per million (ppm) and 30 ppm were studied. We show how PCE causes rapid drop in cell performances for all concentrations including 0.05 ppm. At concentrations of 1 and 0.05 ppm, PCE poisoned the cell at a rate dependent on the dosage of the contaminant delivered to the cell. PCE appears to affect the cell when the cell potential was over potentials higher than approximately 0.2 V. No effects were observed at voltages around or below 0.2 V and the cells could be recovered from previous poisoning performed at higher potentials. Recoveries at those low voltages could be induced by changing the operating voltage or by purging the system. Poisoning did not appear to affect the membrane conductivity. Measurements with long-path length IR results suggested catalytic decomposition of the PCE by hydrogen over the anode catalyst.

COLON-MERCHADO, H.; MARTINEZ-RODRIGUEZ, M.; FOX, E.; RHODES, W.; MCWHORTER, C.; GREENWAY, S.

2011-04-18

34

Determination of bioconcentration potential of tetrachloroethylene in marine algae by 13C.  

PubMed

The use of stable isotope of organic-carbon, organic-13C, as a tracer for the determination of the concentration of tetrachloroethylene (PCE), CA, in Heterosigma akashiwo and Skeletonema costatum was examined. CA determined by the 13C and GC methods showed good agreement with each other. This suggests that it is reasonable and reliable to determine the bioconcentration potential of PCE in marine algae. Fitting values of bioconcentration potential parameters, including uptake rate constant k1, elimination rate constant k2 and bioconcentration factor on the basis of dry weight BCFD, were done not only to the time course for PCE uptake by the algae with the bioconcentration model, but also to experimental data for "percent inhibition(%) approximately exposure concentration of PCE approximately time" with the combined bioconcentration and probability model. The values obtained from the bioconcentration model were consistent with those from the combined bioconcentration and probability model. With the parameters (such as k1, k2, growth rate constant kG, critical concentration of HOCs in the organism resulting in growth inhibition CA* and spread factor S) the variability in toxicity (such as EC10, EC50, EC70) can be estimated from the combined bioconcentration and probability model, which fits well with the experimental observations. PMID:8759313

Wang, X; Harada, S; Watanabe, M; Koshikawa, H; Sato, K; Kimura, T

1996-09-01

35

Tetrachloroethylene metabolism resulting from domestic respiratory exposure: Pharmacokinetic considerations relevant to risk assessment  

SciTech Connect

Physiologically based pharmacokinetic (PBPK) models describing the uptake, metabolism, and excretion of xenobiotic compounds are now proposed for use in regulatory health-risk assessments. In this study we compare how different scenarios for domestic respiratory exposure to tetrachloroethylene (PCE) from ground water influence the extent of PCE metabolism predicted using a PBPK model. Indoor exposure patterns we use as input to the PBPK model are realistic ones generated from a three-compartment model describing volatilization of PCE from domestic water into household air. Values we use for the metabolic parameters of the PBPK model are estimated from data on urinary metabolites in workers exposed to PCE. For respiratory PCE exposure due to typical levels of PCE in ground water, use of time-weighted average air concentrations with a steady-state PBPK model yields estimates of total metabolized PCE similar to those obtained using completely dynamic modeling, despite considerable uncertainty in key exposure and metabolic-model parameters. These findings suggest that, in this case, risk estimation taking pharmacokinetics into account may be accomplished using simple analytic methods. 31 refs., 8 figs., 3 tabs.

Bogen, K.T.; McKone, T.E.

1987-10-01

36

Continuous determination of high-vapor-phase concentrations of tetrachloroethylene using on-line mass spectrometry.  

PubMed

A method was developed to determine the vapor concentration of tetrachloroethylene (PCE) at and below its equilibrium vapor-phase concentration, 168 000 microg/L (25 degrees C). Vapor samples were drawn by vacuum into a six-port sampling valve and injected through a jet separator into an ion trap mass spectrometer (MS). This on-line MS can continuously sample a vapor stream and provide vapor concentrations every 30 s. Calibration of the instrument was done by creating a saturated stream of PCE vapor, sampling the vapor with the on-line MS and with thermal desorption tubes, and correlating the peak area response from the MS with the vapor concentration determined by automated thermal desorption gas chromatography mass spectrometry. Dilution of the saturated stream provided lower concentrations of PCE vapor. The method was developed to monitor the vapor concentration of PCE that was sparged from a two-dimensional flow chamber and for determination of the total PCE mass removed during each sparge event. The method has potential application for analysis of gas-phase tracers. PMID:18205332

Fine, Dennis; Brooks, Michael C; Bob, Mustafa; Mravik, Susan; Wood, Lynn

2008-01-19

37

A risk-based cleanup criterion for PCE in soil. [Tetrachloroethylene  

SciTech Connect

The most important attribute of a chemical contaminant at a hazardous-wastes site for decision makers to consider with regard to its cleanup is the potential risk associated with human exposure. For this reason we have developed a strategy for establishing a risk-based cleanup criterion for chemicals in soil. We describe this strategy by presenting a cleanup criterion for tetrachloroethylene (PCE) in soil associated with a representative California landscape. We being by discussing the environmental fate and transport model, developed at the Lawrence Livermore National Laboratory (LLNL), that we used to predict the equilibrium concentration of PCE in five environmental media from a steady-state source in soil. Next, we explain the concept and application of pathway-exposure factors (PEFs), the hazard index, and cancer-potency factors (CPFs) for translating the predicted concentrations of PCE into estimated potential hazard or risk for hypothetically exposed individuals. Finally, the relationship between concentration and an allowable level of risk is defined and the societal and financial implications are discussed. 22 refs., 6 tabs.

Daniels, J.I.; McKone, T.E.; Hall, L.C.

1990-09-26

38

Kinetic and isotope analyses of tetrachloroethylene and trichloroethylene degradation by model Fe(II)-bearing minerals.  

PubMed

The kinetics and in some cases stable carbon isotope fractionation associated with abiotic reductive dechlorination of tetrachloroethylene (PCE) and trichloroethylene (TCE) by model Fe(II)-bearing minerals present in anaerobic soils were measured. The minerals studied were chloride green rust (GR-Cl), sulfate green rust (GR-SO(4)), pyrite, magnetite, and adsorbed Fe(II) or FeS formed at the surface of goethite by treatment with dissolved Fe(II) or S(-II). We observed some abiotic transformation of PCE and TCE in every system studied, as evidenced by the presence of abiotic reaction products. Bulk enrichment factors (epsilon(bulk) values) for TCE transformation by GR-Cl and pyrite were -23.0+/-1.8 per thousand and -21.7+/-1.0 per thousand, respectively, which are more negative than reported values for microbial TCE dechlorination and could provide one means for distinguishing microbial from abiotic dechlorination of TCE in the environment. Considering the time scale of subsurface remediation technologies, including natural attenuation, minerals such as green rusts, pyrite, and magnetite have the potential to contribute to the transformation of PCE and TCE at contaminated sites. PMID:19111888

Liang, Xiaoming; Philp, R Paul; Butler, Elizabeth C

2008-12-27

39

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

PubMed

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

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

2012-04-12

40

Use of mini-sprinklers to strip trichloroethylene and tetrachloroethylene from contaminated ground water.  

PubMed

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 for approximately 1 h at 0.19 to 0.21 MPa (28 to 30 lb in(-2)) through a mini-sprinkler supported on top of a 1.8-m-tall riser. 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, from mean influent dissolved concentrations of 466 to 1675 microg L(-1) TCE and 206 to 940 microg L(-1) PCE. In terms of mass removed, the mini-sprinklers removed TCE and PCE at a rate of approximately 1400 to 1700 and 700 to 900 microg L(-1), respectively, over a 1-h test period. 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 purging 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 evapotranspiration) excess waste water. PMID:12809281

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

41

Kinetics of the transformation of trichloroethylene and tetrachloroethylene by iron sulfide  

SciTech Connect

The transformation of trichloroethylene (TCE), tetrachloroethylene (PCE), and 1,1-dichloroethylene FeS in aqueous solution at pH 8.3 was studied in batch experiments. TCE and PCE were transformed by FeS with pseudo-first-order rate constants, corrected for partitioning to the sample headspace, of (1.49 [+-] 0.14) [times] 10[sup [minus]3] h[sup [minus]1] (TCE) and (5.7 [+-] 1.0) [times] 10[sup [minus]4] h[sup [minus]1] (PCE). A 17% decrease in the concentration of 1,3-DCE was observed over 120 days; however, no reaction products were detected. TCE and PCE transformation data were fit to a rate law assuming transformation of TCE via parallel reaction pathways to acetylene and cis-1,2-dichloroethylene (cis-DCE) and transformation of PCE via parallel reaction pathways to acetylene and TCE. Acetylene was the major reaction product for both TCE and PCE. Determination of rate constants for each reaction pathway indicated that TCE was transformed to acetylene 11.8 [+-] 1.1 times faster than to cis-DCE and that PCE was transformed to acetylene 8.2 [+-] 1.8 times faster than to TCE. Additional minor reaction products were vinyl chloride (VC) for TCE and cis-DCE for PCE. Detection of acetylene as the major product of both TCE and PCE transformation by FeS contrasts with the sequential hydrogenolysis products typically observed in the microbial transformation of these compounds, making acetylene a potential indicator of abiotic transformation of TCE and PCE by FeS in natural systems.

Butler, E.C.; Hayes, K.F. (Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Civil and Environmental Engineering)

1999-06-15

42

Lactate Injection by Electric Currents for Bioremediation of Tetrachloroethylene in Clay.  

PubMed

Biological transformation of tetrachloroethylene (PCE) in silty clay samples by ionic injection of lactate under electric fields is evaluated. To prepare contaminated samples, a silty clay slurry was mixed with PCE, inoculated with KB-1(®) dechlorinators and was consolidated in a 40 cm long cell. A current density between 5.3 and 13.3 A m(-2) was applied across treated soil samples while circulating electrolytes containing 10 mg L(-1) lactate concentration between the anode and cathode compartments to maintain neutral pH and chemically reducing boundary conditions. The total adsorbed and aqueous PCE was degraded in the soil to trichloroethylene (TCE), cis-1,2-dichloroethene (cis-DCE), vinyl chloride (VC) and ethene in 120 d, which is about double the time expected for transformation. Lactate was delivered into the soil by a reactive transport rate of 3.7 cm(2) d(-1) V(-1). PCE degradation in the clay samples followed zero order transformation rates ranging from 1.5 to 5 mg L(-1) d(-1) without any significant formation of TCE. cis-DCE transformation followed first order transformation rates of 0.06 to 0.10 per day. A control experiment conducted with KB-1 and lactate, but without electricity did not show any significant lactate buildup or cis-DCE transformation because the soil was practically impermeable (hydraulic conductivity of 2×10(-7) cm s(-1)). It is concluded that ionic migration will deliver organic additives and induce biological activity and complete PCE transformation in clay, even though the transformation occurs under slower rates compared to ideal conditions. PMID:23264697

Wu, Xingzhi; Gent, David B; Davis, Jeffrey L; Alshawabkeh, Akram N

2012-06-22

43

Isobaric vapor-liquid equilibria of tetrachloroethylene + 1-propanol and + 2-propanol at 20 and 100 kPa  

SciTech Connect

Isobaric vapor-liquid equilibria were obtained for tetrachloroethylene + 1-propanol and +2-propanol systems at 20 and 100 kPa using a dynamic still. The experimental error in temperature was {+-} 0.1 K, in pressure {+-} 0.01 kPa and {+-} 0.1 kPa for the experiments carried out at 20 and 100 kPa, respectively, and in liquid and vapor composition 0.001. The two systems satisfy the point-to-point thermodynamic consistency test. Both systems show a positive deviation from ideality. The data were well correlated with the Wilson equation.

Dejoz, A.; Gonzalez-Alfaro, V.; Miguel, P.J.; Vazquez, M.I. [Univ. de Valencia (Spain). Dept. de Ingenieria Quimica

1996-11-01

44

Apartment residents' and day care workers' exposures to tetrachloroethylene and deficits in visual contrast sensitivity.  

PubMed Central

Tetrachloroethylene (also called perchloroethylene, or perc), a volatile organic compound, has been the predominant solvent used by the dry-cleaning industry for many years. The U.S. Environmental Protection Agency (EPA) classified perc as a hazardous air pollutant because of its potential adverse impact on human health. Several occupational studies have indicated that chronic, airborne perc exposure adversely affects neurobehavioral functions in workers, particularly visual color discrimination and tasks dependent on rapid visual-information processing. A 1995 study by Altmann and colleagues extended these findings, indicating that environmental perc exposure at a mean level of 4,980 microg/m(3) (median=1,360 microg/m(3)) alters neurobehavioral functions in residents living near dry-cleaning facilities. Although the U.S. EPA has not yet set a reference concentration guideline level for environmental exposure to airborne perc, the New York State Department of Health set an air quality guideline of 100 microg/m(3). In the current residential study, we investigated the potential for perc exposure and neurologic effects, using a battery of visual-system function tests, among healthy members of six families living in two apartment buildings in New York City that contained dry-cleaning facilities on the ground floors. In addition, a day care investigation assessed the potential for perc exposure and effects among workers at a day care center located in the same one-story building as a dry-cleaning facility. Results from the residential study showed a mean exposure level of 778 microg/m(3) perc in indoor air for a mean of 5.8 years, and that perc levels in breath, blood, and urine were 1-2 orders of magnitude in excess of background values. Group-mean visual contrast sensitivity (VCS), a measure of the ability to detect visual patterns, was significantly reduced in the 17 exposed study participants relative to unexposed matched-control participants. The groups did not differ in visual acuity, suggesting that the VCS deficit was of neurologic origin. Healthy workers in the day care investigation were chronically exposed to airborne perc at a mean of 2,150 microg/m(3) for a mean of 4.0 years. Again, group-mean VCS, measured 6 weeks after exposure cessation, was significantly reduced in the nine exposed workers relative to matched controls, and the groups did not differ significantly in visual acuity. These results suggested that chronic, environmental exposure to airborne perc adversely affects neurobehavioral function in healthy individuals. Further research is needed to assess the susceptibility of the young and elderly to perc-induced effects, to determine whether persistent solvent-induced VCS deficits are a risk factor for the development of neurologic disease, and to identify the no observable adverse effect level for chronic, environmental, perc exposure in humans.

Schreiber, Judith S; Hudnell, H Kenneth; Geller, Andrew M; House, Dennis E; Aldous, Kenneth M; Force, Michael S; Langguth, Karyn; Prohonic, Elizabeth J; Parker, Jean C

2002-01-01

45

Interfacial Properties of a Hydrophobic Dye in the Tetrachloroethylene-Water-Glass Systems  

SciTech Connect

Interfacial effects play an important role in governing multiphase fluid behavior in porous media. Strongly hydrophobic organic dyes, used in many experimental studies to facilitate visual observation of the phase distributions, have generally been implicitly assumed to have no influence on the interfacial properties of the various phases in porous media. Sudan IV is the most commonly used dye for non-aqueous phase liquids (NAPLs) in laboratory experiments. It has also been used in at least one field experiment. The effects of this dye on the tetrachloroethylene (PCE)-water-glass system were investigated to test the assumption that the dye does not effect the interfacial properties and therefore PCE mobility. The results indicate that the dye does indeed change the interfacial relationships.The effect of the dye on the interfacial relationships is a complex function of the dye concentration, the solid phase composition, and the dynamic rate of new interface formation. The dye caused a slight (<10 percent) increase in interfacial tension at low concentrations (<0.1 g/L) and high rates of new interface formation. The dye reduced interfacial tension between PCE and water at low rates of new interface formation for all dye concentrations tested (0.00508 to 5.08 g/L). At the highest dye concentration, the PCE-water interfacial tension was significantly reduced regardless of the rate of new interface formation. The apparent interfacial tension increase at low dye concentrations is suspected to be an artifact of a low measured IFT value for the undyed PCE caused by leaching of rubber o-rings by the PCE prior to testing in the final drop-volume configuration.In addition to reducing interfacial tension, the dye was found to significantly alter the wetting relationship between PCE and water on a glass surface at and above the range of reported dye concentrations cited in the literature (1.1 to 1.7 g/L). The wetting relationship was rendered neutral from a water-wet initial condition at the highest dye concentration. The contact angle, measured through the aqueous phase, changed from 58 degrees for undyed PCE to 93 degrees at a dye concentration of 5.08 g/L. Complete reversal of the wettability is likely given the short equilibration time used in this study (approximately five minutes) together with literature indications that hundreds to thousands of hours may be required to reach equilibrium during contact angle measurements. Observations suggesting changing wetting relationships were also noted between PCE, water, and the platinum-iridium surface used in the standard du No/374y ring method for measuring interfacial tension.Observations of the dyed-PCE-water interface behavior during du No/374y ring interfacial tension measurements were similar to observations noted previously during measurements of the interfacial tension between the Savannah River Site (SRS) M-Area Settling Basin DNAPL (M-Area DNAPL) and water. This observation suggests that the M-Area DNAPL may contain surface active components. If this proves to be the case, it would have significant implications for how the M-Area DNAPL is distributed and moves in the SRS subsurface.

Tuck, D.M.

1999-02-23

46

Assessing interaction thresholds for trichloroethylene in combination with tetrachloroethylene and 1,1,1-trichloroethane using gas uptake studies and PBPK modeling  

Microsoft Academic Search

The volatile organic solvents trichloroethylene (TCE), tetrachloroethylene (perchloroethylene, PERC), and 1,1,1-trichloroethane (methylchloroform, MC) are widely distributed environmental pollutants and common contaminants of many chemical waste sites. To investigate the mode of pharmacokinetic interactions among TCE, PERC, and MC and to calculate defined \\

Ivan D. Dobrev; Melvin E. Andersen; Raymond S. Yang

2001-01-01

47

Destruction of pollutants in water with ozone in combination with ultraviolet radiation. 1. General principles and oxidation of tetrachloroethylene  

SciTech Connect

Oxidation of organic micropollutants in water is significantly faster with ozone in combination with ultraviolet radiation than one would predict on the basis of the individual processes involved. A formalism for the analysis of O/sub 3//UV kinetics is presented in which substrate decay is represented as a linear combination of terms representing purging, ozonation, photolysis, and photolytic ozonation (O/sub 3//UV). For the substrate tetrachloroethylene (TCE) the process is overall first order in TCE. With a continuously sparged stirred tank reactor, times for the elimination of 63% of the substrate (T/sub 1/) have values of 100, 26, 20, and 7 min for purging, ozonation only, photolysis only, and photolytic ozonation, respectively. Significant retardation of O/sub 3//UV kinetics is observed in a lake-water matrix as opposed to purified water, possible due to a radical intermediate involved in the O/sub 3//UV process.

Peyton, G.R.; Huang, F.Y.; Burleson, J.L.; Glaze, W.H.

1982-08-01

48

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

SciTech Connect

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.

Burris, D.R.; Smith, M.H. [Armstrong Lab., Tyndall Air Force Base, FL (United States); Delcomyn, C.A. [Applied Research Associates, Inc., Tyndall Air Force Base, FL (United States); Roberts, A.L. [Johns Hopkins Univ., Baltimore, MD (United States)

1996-10-01

49

Tetrachloroethylene-contaminated drinking water in Massachusetts and the risk of colon-rectum, lung, and other cancers.  

PubMed Central

We conducted a population-based case-control study to evaluate the relationship between cancer of the colon-rectum (n = 326), lung (n = 252), brain (n = 37), and pancreas (n = 37), and exposure to tetrachloroethylene (PCE) from public drinking water. Subjects were exposed to PCE when it leached from the vinyl lining of drinking-water distribution pipes. Relative delivered dose of PCE was estimated using a model that took into account residential location, years of residence, water flow, and pipe characteristics. Adjusted odds ratios (ORs) for lung cancer were moderately elevated among subjects whose exposure level was above the 90th percentile whether or not a latent period was assumed [ORs and 95% confidence intervals (CIs), 3.7 (1.0-11.7), 3.3 (0.6-13.4), 6.2 (1.1-31.6), and 19.3 (2.5-141.7) for 0, 5, 7, and 9 years of latency, respectively]. The adjusted ORs for colon-rectum cancer were modestly elevated among ever-exposed subjects as more years of latency were assumed [OR and CI, 1.7 (0.8-3.8) and 2.0 (0.6-5.8) for 11 and 13 years of latency, respectively]. These elevated ORs stemmed mainly from associations with rectal cancer. Adjusted ORs for rectal cancer among ever-exposed subjects were more elevated [OR and CI, 2.6 (0. 8-6.7) and 3.1 (0.7-10.9) for 11 and 13 years of latency, respectively] than were corresponding estimates for colon cancer [OR and CI, 1.3 (0.5-3.5) and 1.5 (0.3-5.8) for 11 and 13 years of latency, respectively]. These results provide evidence for an association between PCE-contaminated public drinking water and cancer of the lung and, possibly, cancer of the colon-rectum.

Paulu, C; Aschengrau, A; Ozonoff, D

1999-01-01

50

Prenatal exposure to tetrachloroethylene-contaminated drinking water and the risk of congenital anomalies: a retrospective cohort study  

PubMed Central

Background Prior animal and human studies of prenatal exposure to solvents including tetrachloroethylene (PCE) have shown increases in the risk of certain congenital anomalies among exposed offspring. Objectives This retrospective cohort study examined whether PCE contamination of public drinking water supplies in Massachusetts influenced the occurrence of congenital anomalies among children whose mothers were exposed around the time of conception. Methods The study included 1,658 children whose mothers were exposed to PCE-contaminated drinking water and a comparable group of 2,999 children of unexposed mothers. Mothers completed a self-administered questionnaire to gather information on all of their prior births, including the presence of anomalies, residential histories and confounding variables. PCE exposure was estimated using EPANET water distribution system modeling software that incorporated a fate and transport model. Results Children whose mothers had high exposure levels around the time of conception had an increased risk of congenital anomalies. The adjusted odds ratio of all anomalies combined among children with prenatal exposure in the uppermost quartile was 1.5 (95% CI: 0.9, 2.5). No meaningful increases in the risk were seen for lower exposure levels. Increases were also observed in the risk of neural tube defects (OR: 3.5, 95% CI: 0.8, 14.0) and oral clefts (OR 3.2, 95% CI: 0.7, 15.0) among offspring with any prenatal exposure. Conclusion The results of this study suggest that the risk of certain congenital anomalies is increased among the offspring of women who were exposed to PCE-contaminated drinking water around the time of conception. Because these results are limited by the small number of children with congenital anomalies that were based on maternal reports, a follow-up investigation should be conducted with a larger number of affected children who are identified by independent records.

2009-01-01

51

Neurotoxicologic examination of rats exposed to 1,1,2,2-tetrachloroethylene (perchloroethylene) vapor for 13 weeks.  

PubMed

Large evoked potential and EEG changes occurred in a pilot study in Fischer 344 rats during exposure to 800 ppm of 1,1,2,2-tetrachloroethylene [perchloroethylene (Perc)], a cleaning solvent with anesthetic properties. In the main study, rats were evaluated for persistent nervous system effects the week following exposure to 0, 50, 200, or 800 ppm Perc for 6 h/day, 5 days/week, for 13 weeks. The only effect related to treatment was in the flash evoked potential (FEP-V), recorded from the visual cortex. The longer latency potentials (N3) of the FEP-V had a greater amplitude in the 800 ppm Perc group. The FEP-Vs were of normal shape and latency. Although mild neurotoxicity could not be ruled out completely, amplitude changes in N3 can occur for a variety of psychophysiological reasons other than neurotoxicity. Consequently, as a stand-alone finding, the toxicologic significance of the larger FEP in the 800 ppm exposure group was unknown. Other data did not support a diagnosis of neurotoxicity. No treatment-related alterations were noted in expanded clinical observations, in the FEP recorded from the cerebellum (as opposed to visual cortex FEP-V), or in auditory, somatosensory, or caudal nerve evoked potentials. No treatment-related lesions were noted during histopathologic examination of eyes, optic nerves, optic tract, or multiple sections of brain, spinal cord, peripheral nerves, or limb muscles. The no-observed-effect-level (NOEL) was 200 ppm, based on increased amplitude of the longer latency potentials of the FEP at 800 ppm. PMID:9511173

Mattsson, J L; Albee, R R; Yano, B L; Bradley, G; Spencer, P J

52

HEALTH EFFECTS ASSESSMENT FOR TETRACHLOROETHYLENE  

EPA Science Inventory

The document represents a brief, quantitatively oriented scientific summary of health effects data. It was developed by the Environmental Criteria and Assessment Office to assist the Office of Emergency and Remedial Response in establishing chemical-specific health-related goals ...

53

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...

54

UPDATED HEALTH EFFECTS ASSESSMENT FOR TETRACHLOROETHYLENE  

EPA Science Inventory

This report summarizes and evaluates information relevant to a preliminary interim assessment of adverse health effects associated with specific chemicals or compounds. The Office of Emergency and Remedial Response (Superfund) uses these documents in preparing cost-benefit analys...

55

Arc products of transformer insulating systems containing tetrachloroethylene. Final report  

SciTech Connect

A low current laboratory arc interruption cell was adapted to study the arc products of Wecosol (C/sub 2/Cl/sub 4/) and 75W% C/sub 2/Cl/sub 4/-25W% mineral oil-solid insulation systems for fire resistant transformers to determine the toxicity hazard of arc failures of these transformers. The use of the relatively low current (40 to 50 ampere) arcs was justified on the basis that their maximum temperature was above the chemical reaction temperatures just as in the case of kiloampere arc failures of transformers. Analytical methods were developed to determine arc products, principally for COCl/sub 2/ (phosgene). A relative hazard criterion is presented. The major arc products of the Wecosol systems are Cl/sub 2/, HCl, C/sub 2/Cl/sub 6/ (reaction of Cl/sub 2/ + C/sub 2/Cl/sub 4/) and CCl/sub 4/, and the minor products are COCl/sub 2/, CO and CO/sub 2/. The principal arc failure hazard here would be due to Cl/sub 2/ and HCl, and there is a low probability of COCl/sub 2/ and CO hazards. The major arc products in the 75W% C/sub 2/Cl/sub 4/ + 25W% mineral oil systems are HCl and CCl/sub 4/, and HCl would present the principal arc failure hazard. The minor products include COCl/sub 2/ and H/sub 2/, and COCl/sub 2/ would present a low probability of toxicity hazard. The levels of H/sub 2/ were well below the explosive limits of H/sub 2/ and air. It was concluded that failure arc products from these C/sub 2/Cl/sub 4/ fluid based transformers should not be hazardous in most instances of failure, and that simple precautions would be sufficient to assure safe access and handling. 6 figs., 11 tabs.

Baum, B.; Boshart-Mikes, G.; Mikes, F.; Mulak, M.; Peck, W.R.; Mandelcorn, L.; Jones, E.A.; Marshall, G.R.; Studniartz, S.A.

1986-03-01

56

[Tetrachloroethylene: effect of low concentrations of 1,1,2,2-tetrachloroethylene (perchloroethylene) on the mouse. II. Study of tetrachloroethylene in various organs and demonstration of histological changes in the examined organs].  

PubMed

Perchlorethylene in subacute amounts in form of contaminated drinking-water was given to a group of NMRI-mice (group A = 0,05 mg PER/kg BW/d and group B = 0,1 mg PER/kg BW/d) over a period of seven weeks. The histologic changes of various organs and the perchlorethylene-residues in the examined organs have been determined. We only could establish the light-microscopic perceivable histologic changes in the spleen. Thus the pulpa cords were rich in erythrocytes and the area of the red pulpa contained plenty of blood-formation-centers with megakaryocytes. In the spleens of group B a siderin-storage in the red pulpa in macrophages could be established. These results are indicative for an increased hemolysis. In all of the examined organs, the heaviest accumulation of perchlorethylene we could be established in the spleen, whereby the concentration in the spleen amounted to several times as much as the residue-examinations of the other organs. In the liver for instance an insignificant amount of PER was stored. The erythrocytes and the fragments of them, that have been changed by the storage of PER are being decomposed in the spleen, and perchlorethylene reaches the spleen via the erythrocytes. PMID:4096156

Marth, E; Stünzner, D; Binder, H; Möse, J R

1985-12-01

57

Tetrachloroethylene Metabolism Resulting from Domestic Respiratory Exposure: Pharmacokinetic Considerations Relevant to Risk Assessment.  

National Technical Information Service (NTIS)

Physiologically based pharmacokinetic (PBPK) models describing the uptake, metabolism, and excretion of xenobiotic compounds are now proposed for use in regulatory health-risk assessments. In this study the authors compare how different scenarios for dome...

K. T. Bogen T. E. McKone

1987-01-01

58

INFLUENCE OF VISCOUS AND BUOYANCY FORCES ON THE MOBILIZATION OF RESIDUAL TETRACHLOROETHYLENE DURING SURFACTANT FLUSHING  

EPA Science Inventory

The potential for nonaqueous phase liquid (NAPL) mobilization is one of the most important considerations in the development and implementation of surfactant-based remediation technologies. Column experiments were performed to investigate the onset and extent of tetrachloroethyle...

59

Destruction of pollutants in water with ozone in combination with ultraviolet radiation. 1. General principles and oxidation of tetrachloroethylene  

Microsoft Academic Search

Oxidation of organic micropollutants in water is significantly faster with ozone in combination with ultraviolet radiation than one would predict on the basis of the individual processes involved. A formalism for the analysis of Oā\\/UV kinetics is presented in which substrate decay is represented as a linear combination of terms representing purging, ozonation, photolysis, and photolytic ozonation (Oā\\/UV). For the

Gary R. Peyton; Francis Y. Huang; Jimmie L. Burleson; William H. Glaze

1982-01-01

60

Ultrastructure of a bio-electrolytic methanogenic/methanotrophic granular biofilm for the complete degradation of tetrachloroethylene in contaminated groundwater.  

PubMed

The electrolytical methanogenic/methanotrophic coupling (eMaMoC) process was tested in a laboratory-scale single-stage reactor for the treatment of tetrachloroethene (PCE)-contaminated waters. A water electrolysis cell was placed directly in the effluent recirculation loop for the supply of both O2 and H2 to the system: H2 serving as the electron donor for both carbonate reduction into CH4 and reductive dechlorination. The concurrent presence of O2 and CH4 could be used by the methanotrophs for co-metabolically oxidising the chlorinated intermediates left over by the anaerobic transformation of PCE. At a PCE inlet of 33-52 microM and a hydraulic residence time (HRT) of 5.6 days, PCE reductive dechlorination to dichloroethene (DCE) was over 95% with a maximum DCE mineralisation of 83%. Fluorescence in situ hybridisation with 16S rRNA probes related to type I and type II methanotrophic bacteria were utilised to localise the methanotrophic communities in the anaerobic/aerobic granules. It evidenced that with operational time, along with increasing oxygenation rate, methanotrophic communities were specifically colonising onto the outermost layer of the anaerobic/aerobic granule. PMID:17547018

Guiot, S R; Kuhn, R; Lévesque, M J; Cimpoia, R

2007-01-01

61

SURFACTANT ENHANCED RECOVERY OF TETRACHLOROETHYLENE FROM A POROUS MEDIUM CONTAINING LOW PERMEABILITY LENSES. 2. NUMERICAL SIMULATION. (R825409)  

EPA Science Inventory

Abstract A numerical model of surfactant enhanced solubilization was developed and applied to the simulation of nonaqueous phase liquid recovery in two-dimensional heterogeneous laboratory sand tank systems. Model parameters were derived from independent, small-scale, ...

62

Reductive dechlorination of tetrachloroethylene and trichloroethylene by mackinawite (FeS) in the presence of metals: reaction rates.  

PubMed

Reductive dechlorination by mackinawite (FeS) is an important transformation pathway for chloroethylenes in anoxic environments. Yet, the impact of metals on reductive dechlorination is not well understood, despite their frequent cooccurrence with chloroethylenes. Fe(II), Co(II), Ni(II), and Hg(II) were evaluated for their impact on the dechlorination rates of PCE and TCE by FeS. Compared with unamended FeS batches, the dechlorination rates of both chloroethylenes decreased by addition of 0.01 M Fe(II). Relative to 0.01 M Fe(II)-added FeS batches, the dechlorination rates increased in FeS batches amended with 0.01 M of Co(II) and Hg(II), whereas the rates decreased in 0.01 M Ni(II)-added batches. While significantly impacting the dechlorination rates, the amended metals were quantitatively sequestered by FeS mainly because of formation of metal sulfides. Comparison of the dechlorination rates between metal-added FeS batches and metal sulfide batches suggests that discrete metal sulfides do not form in metal-added FeS batches. The observed exceptionally high reactivity of CoS suggests that it may be useful in reactive permeable barrier applications because of its stability in anoxic waters. The dechlorination rates of PCE and TCE significantly varied with Fe(ll) amendment concentrations (Fe(II)0), indicating the presence of different types of solid-bound Fe phases with Fe(II)o. PMID:17948784

Jeong, Hoon Y; Hayes, Kim F

2007-09-15

63

Volatile halocarbons in butter: elevated tetrachloroethylene levels in samples obtained in close proximity to dry-cleaning establishments  

SciTech Connect

In recent years materials not directly associated with food production, such as polychlorinated and brominated biphenyls, have been found in foods. According to the criteria to evaluate the likelihood for a chemical to contaminate food, the volatile halocarbons (VHCs) were selected as target compounds in an examination for potential contaminants in selected foods. The technique of multiple headspace extraction (MHE) was used in this study to minimize sample handling, and thereby reduce the potential for laboratory contamination and maximize throughput. Recently this laboratory reported findings of several VHCs in margarine, including PCE in four samples at levels above the usual background findings. Those samples had been obtained from a food store located immediately next to a dry-cleaning establishment. Follow-up investigation was conducted to determine the frequency of occurrence and levels of PCE that may be present in fatty foods purchased from stores located both near and distant from dry cleaners. Butter was chosen as a model food because it is a highly uniform product of very high fat content, which would be expected to act as a good absorber of the lipophilic VHCs. This paper presents results of these analyses and correlations between level of VHCs in butter and the proximity to dry cleaners of the food store where the butter was purchased.

Miller, L.J.; Uhler, A.D.

1988-09-01

64

Quantitation of the tetrachloroethylene metabolite N-acetyl-S-(trichlorovinyl)cysteine in rat urine via negative ion chemical ionization gas chromatography/tandem mass spectrometry.  

PubMed

A sensitive and selective negative ion chemical ionization gas chromatographic/tandem mass spectrometric (NICI GC/MS/MS) method was developed for the determination of the tetrachlorethylene metabolite, N-acetyl-S-(trichlorovinyl)cysteine (TCVC), in rat urine. Urine samples were fortified with a 13C,D2-analog of TCVC, acidified and extracted with ethyl acetate. The extract were derivatized with methanolic HCl, and the resulting methyl esters analyzed via NICI GC/MS/MS. Detection of the TCVC analogs was performed by monitoring the Cl- product ion of M-Cl2C2HS-. The limit of detection for TCVC by this method was estimated to be 0.1 ng ml-1 urine (3 x noise). The quantitation limit was determined to be 0.3 ng TCVC per milliliter of urine. The method was found to be linear for TCVC concentrations from 0.3 to 104 ng ml-1 urine. Relative recovery of TCVC from urine ranged from 95.4% to 108.5%. Additional data are given for GC/MS and GC/MS/MS analysis of the pentafluoro-benzyl ester derivative of TCVC. Data are also presented for the isolation and analysis of this compound obtained from dosed rats. PMID:7811758

Bartels, M J

1994-11-01

65

40 CFR 148.10 - Waste specific prohibitions-solvent wastes.  

Code of Federal Regulations, 2013 CFR

...acetate Ethyl benzene Ethyl ether Isobutanol Methanol Methylene chloride Methylene chloride (from the pharmaceutical industry) Methyl ethyl ketone Methyl isobutyl ketone Nitrobenzene Pyridine Tetrachloroethylene Toulene...

2013-07-01

66

40 CFR 148.10 - Waste specific prohibitions-solvent wastes.  

Code of Federal Regulations, 2010 CFR

...acetate Ethyl benzene Ethyl ether Isobutanol Methanol Methylene chloride Methylene chloride (from the pharmaceutical industry) Methyl ethyl ketone Methyl isobutyl ketone Nitrobenzene Pyridine Tetrachloroethylene Toulene...

2010-07-01

67

40 CFR 433.11 - Specialized definitions.  

Code of Federal Regulations, 2011 CFR

...Bis (2-chloroethoxy) methane Methylene chloride (dichloromethane) Methyl chloride (chloromethane) Methyl bromide (bromomethane...Tetrachloroethylene Toluene Trichloroethylene Vinyl chloride (chloroethylene) Aldrin Dieldrin...

2011-07-01

68

Ground-penetrating radar monitoring of a controlled DNAPL release: 200 MHz radar  

Microsoft Academic Search

A controlled release of tetrachloroethylene was performed in a saturated, natural sandy aquifer to evaluate the effectiveness of various geophysical techniques for detecting and monitoring dense nonaqueous phase liquids (DNAPLs) in the subsurface. Tetrachloroethylene, typical of most DNAPLs, has a low relative dielectric permittivity (2.3), which contrasts with the high relative permittivity (80) of the pore water it displaces, making

Michael L. Brewster; A. P. Annan

1994-01-01

69

Mixed Waste Management Facility (MWMF) Groundwater Monitoring Report: Fourth quarter 1991 and 1991 summary.  

National Technical Information Service (NTIS)

During fourth quarter 1991, tritium, trichloroethylene, tetrachloroethylene, chloroethene (vinyl chloride), total radium, mercury, and lead exceeded the US Environmental Protection Agency primary drinking water standards (PDWS) in groundwater samples from...

C. Y. Thompson

1992-01-01

70

The Reactions of Carbon Atoms with Chlorinated Hydrocarbons.  

National Technical Information Service (NTIS)

The reaction of carbon atoms with carbon tetrachloride yields two products, tetrachloroethylene and octachloropropane. Carbon atoms react with chloroform in a similar manner, yielding trichloroethylene (84%) and 1,1,2,2,3,3,-hexachloropropane (16%). The r...

P. S. Skell R. F. Harris

1965-01-01

71

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 ...

72

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...

73

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...

74

IMPACT OF COSOLVENT FLUSHING ON SUBSURFACE MICROBIAL ECOLOGY AT THE FORMER SAGE'S DRY CLEANER SITE  

EPA Science Inventory

The Solvent Extraction Residual Biotreatment (SERB) technology was evaluated at the former Sage's Dry Cleaner site in Jacksonville, FL where an area of tetrachloroethylene (PCE) contamination was identified. The SERB technology is a treatment train approach to complete site rest...

75

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 ...

76

40 CFR Table 5 to Part 455 - BAT and NSPS Effluent Limitations for Priority Pollutants for Direct Discharge Point Sources That...  

Code of Federal Regulations, 2011 CFR

...Dibromochloromethane 794 196 Dichloromethane 170 36 Ethylbenzene 380 142 Lead (Total) 690 320 Naphthalene 47 19 Phenol 47 19 Tetrachloroethylene 164 52 Tetrachloromethane 380 142 Toluene 74 28 Tribromomethane 794...

2011-07-01

77

40 CFR Table 4 to Part 455 - BAT and NSPS Effluent Limitations for Priority Pollutants for Direct Discharge Point Sources That...  

Code of Federal Regulations, 2011 CFR

...Dibromochloromethane 794 196 Dichloromethane 89 40 Ethylbenzene 108 32 Lead (Total) 690 320 Naphthalene 59 22 Phenol 26 15 Tetrachloroethylene 56 22 Tetrachloromethane 38 18 Toluene 80 26 Tribromomethane 794...

2011-07-01

78

40 CFR 469.12 - Specialized definitions.  

Code of Federal Regulations, 2011 CFR

...Dichlorobenzene 1,4, Dichlorobenzene ethylbenzene 1,1,1 Trichloroethane methylene chloride naphthalene 2 Nitrophenol phenol bis (2-ethylhexyl) phthalate tetrachloroethylene toluene trichloroethylene 2 Chlorophenol 2,4 Dichlorophenol...

2011-07-01

79

FIELD EVALUATION OF A SIMPLE MICROCOSM SIMULATING THE BEHAVIOR OF VOLATILE ORGANIC COMPOUNDS IN SUBSURFACE MATERIALS  

EPA Science Inventory

A simple batch microcosm had previously been developed to simulate the behavior of volatile organic compounds in unconsolidated subsurface material. The microcosm was evaluated by comparing the behavior of tetrachloroethylene, bromoform, carbon tetrachloride, 1,2-dichlorobenzene,...

80

FIELD EVALUATION OF THE SOLVENT EXTRACTION RESIDUAL BIOTREATMENT (SERB) TECHNOLOGY  

EPA Science Inventory

The Solvent Extraction Residual Biotreatment (SERB) technology was demonstrated at the former Sage's Dry Cleaner site in Jacksonville, FL where an area of PCE (tetrachloroethylene) contamination was identified. The SERB technology is a treatment train approach to complete site...

81

EMISSIONS OF PERCHLOROETHYLENE FROM DRY CLEANED FABRICS  

EPA Science Inventory

The paper gives results of an evaluation of emissions of perchloroethylene (tetrachloroethylene) from dry cleaned fabrics to determine: how introducing fresh dry cleaning into a home affects the indoor concentration of perchloroethylene, and the effectiveness of "airing out" dry ...

82

CATALYTIC HYDRODEHALOGENATION OF CHLORINATED ETHYLENES USING PALLADIUM AND HYDROGEN FOR THE TREATMENT OF CONTAMINATED WATER. (R825689C054,R825689C060)  

EPA Science Inventory

Abstract A kinetic model is presented for the catalytic hydrodehalogenation of chlorinated ethylenes using Pd and H2 under water treatment conditions. All five chlorinated ethylenes, including tetrachloroethylene (PCE) and vinyl chloride, were completely rem...

83

Hydrogeologic Framework, Ground Water Quality, and Simulation of Ground Water Flow at the Fair Lawn Well Field Superfund Site, Bergen County, New Jersey.  

National Technical Information Service (NTIS)

Production wells in the Westmoreland well field, Fair Lawn, Bergen County, New Jersey (the 'Fair Lawn well field Superfund site'), are contaminated with volatile organic compounds, particularly trichloroethylene, tetrachloroethylene, and 1,1,1-trichloroet...

J. C. Lewis-Brown D. E. Rice R. Rosman N. P. Smith

2004-01-01

84

40 CFR 467.02 - General definitions.  

Code of Federal Regulations, 2013 CFR

...fluoranthene isophorone napthalene N-nitro sodi phenyl amine phenol benzo(a) pyrene benzo(ghi)perylene fluorene phenanthrene dibenzo(a,h) anthracene indeno(1,2,3-c,d)pyrene pyrene tetrachloroethylene...

2013-07-01

85

40 CFR 464.11 - Specialized definitions.  

Code of Federal Regulations, 2013 CFR

...anthracene (1,2-benzanthracene) 73. benzo (a)pyrene (3,4-benzopyrene) 76. chrysene 78. anthracene 80. fluorene 81. phenanthrene 84. pyrene 85. tetrachloroethylene 86. toluene (3) Dust Collection Scrubber (Ā§...

2013-07-01

86

Decomposition of chloroethenes in electron beam irradiation  

Microsoft Academic Search

Decomposition of tetrachloroethylene and other chloroethenes in electron beam irradiation were examined in order to get information on treatment of industrial off-gas. The G-values of decomposition were larger in the order of tetrachloro->trichloro->trans-dichloro->cis-dichloro->monochloro-ethylene. For tetrachloroethylene, the effect of initial concentration on G-value of decomposition was also examined. The G-values of decomposition increased with the initial concentration. Decomposition mechanism and the

Teruyuki Hakoda; Guo Zhang; Shoji Hashimoto

1999-01-01

87

Characterization of Chloroethylene Dehalogenation by Cell Extracts of Desulfomonile tiedjei and Its Relationship to Chlorobenzoate Dehalogenation  

PubMed Central

We characterized the reductive dehalogenation of tetrachloroethylene in cell extracts of Desulfomonile tiedjei and compared it with this organism's 3-chlorobenzoate dehalogenation activity. Tetrachloroethylene was sequentially dehalogenated to trichloro- and dichloroethylene; there was no evidence for dichloroethylene dehalogenation. Like the previously characterized 3-chlorobenzoate dehalogenation activity, tetrachloroethylene dehalogenation was heat sensitive, not oxygen labile, and increased in proportion to the amount of protein in assay mixtures. In addition, both dehalogenation activities were dependent on hydrogen or formate as an electron donor and had an absolute requirement for either methyl viologen or triquat as an electron carrier in vitro. Both activities appear to be catalyzed by integral membrane proteins with similar solubilization characteristics. Dehalogenation of tetrachloroethylene was inhibited by 3-chlorobenzoate but not by the structural isomers 2- and 4-chlorobenzoate. The last two compounds are not substrates for D. tiedjei. These findings lead us to suggest that the dehalogenation of tetrachloroethylene in D. tiedjei is catalyzed by a dehalogenase previously thought to be specific for meta-halobenzoates.

Townsend, G. T.; Suflita, J. M.

1996-01-01

88

Liquid-core optical fibres  

Microsoft Academic Search

The liquid-core fiber consists essentially of a glass tube with a bore diameter in the range from 50 to 100 micrometers and a wall thickness of about the same value. The bore of the tube is filled with a liquid. Liquids which can be used include tetrachloroethylene and hexachlorobutadiene. The cladding of the fiber is usually made of silica glass.

G. P. Kidd; D. R. Nicol; G. J. Ogilvie

1975-01-01

89

Anionic surfactant remediation of soil columns contaminated by nonaqueous phase liquids  

Microsoft Academic Search

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

V. Dwarakanath; K Kostarelos; Gary A Pope; Doug Shotts; William H Wade

1999-01-01

90

Kinetics and modeling of reductive dechlorination at high PCE and TCE concentrations  

Microsoft Academic Search

Two biokinetic models employing the Michaelis- Menten equation for anaerobic reductive dechlorination of tetrachloroethylene (PCE) and trichloroethylene (TCE) were developed. The models were compared with results from batch kinetic tests conducted over a wide range of PCE and TCE concentrations with two different dechlorin- ating cultures. One model applies Michaelis-Menten ki- netics with competitive inhibition among chlorinated aliphatic hydrocarbons (CAHs),

Seungho Yu; Lewis Semprini

2004-01-01

91

Localized Scleroderma after Exposure to Organic Solvents  

Microsoft Academic Search

A 26-year-old female developed plaques characteristic of morphea on the volar surfaces of the forearms and on the dorsal surfaces on the ankles following an exposure to trichloroethylene, tetrachloroethylene and other solvents by inhalation. Exposure to chemicals has been known to be important as a provoking factor of systemic sclerosis. This patient shows that exposure to solvents could provoke localized

L. Czirjįk; E. Pócs; G. Szegedi

1994-01-01

92

Impact of Source Zone Architecture on DNAPL Dissolution in Systems Containing Organic Wet Porous Media  

Microsoft Academic Search

Subsurface wettability is an important property that impacts our ability to accurately characterize DNAPL source zones. Its variability creates uncertainty in predictions of the fate of DNAPLs in the subsurface. The purpose of this study was to explore and quantify the impact of spatial wettability variations on DNAPL migration, entrapment, and dissolution. Tetrachloroethylene (PCE), a representative DNAPL, was injected into

A. J. Oleniuk; D. M. O'Carroll; L. M. Abriola

2008-01-01

93

Infiltration of PCE in a system containing spatial wettability variations  

Microsoft Academic Search

A two-dimensional infiltration experiment was conducted to investigate and quantify the effect of spatial wettability variations on DNAPL migration and entrapment in saturated sands. Experimental observations of tetrachloroethylene (PCE) infiltration showed that organic-wet sand lenses acted as very effective capillary barriers, retaining PCE and inhibiting its downward migration. A multiphase numerical simulator was used to model this sand box experiment.

Denis M. O'Carroll; Scott A. Bradford; Linda M. Abriola

2004-01-01

94

Glycidyl Esters of Aromatic Acids  

Microsoft Academic Search

The reaction of substituted benzoic acids, dicarboxylic acids such as phthalic, terephthalic, and isophthalic acids, and the sodium or potassium salts of these acids with equimolar or excess epichlorohydrin in the presence of benzyltrimethylammonium chloride has been studied using various solvents such as toluene, dioxane, monochlorobenzene, and tetrachloroethylene. Use of the free carboxylic acids gave only fair to low yields

Yoshio Tanaka; Hiroshi Kakiuchi

1967-01-01

95

Chlorination byproducts induce gender specific autistic-like behaviors in CD1 mice  

Microsoft Academic Search

In 2000, the Agency for Toxic Substances and Disease Registry (ATSDR) released a report concerning elevated autism prevalence and the presence water chlorination byproducts in the municipal drinking water supply in Brick Township, New Jersey. The ATSDR concluded that it was unlikely that these chemicals, specifically chloroform, bromoform (Trihalomethanes; THMs) and tetrachloroethylene (Perchloroethylene; PCE) had contributed to the prevalence of

Sara Rose Guariglia; Edmund C. Jenkins; Kathryn K. Chadman; Guang Y. Wen

96

Evaluation of effectiveness of ground water screening with a field GC  

Microsoft Academic Search

During an environmental investigation of a potential tetrachloroethylene (PCE) source at a manufacturing facility in Wisconsin, A geoprobe and mobile gas-chromatography (GC) were utilized to rapidly screen ground water samples, thus identifying locations for monitoring wells and depths at which to install well screens. The results are used to evaluate the benefits for using a geoprobe with mobile GC for

Ziegler

1995-01-01

97

A comparison between sun and wind as energy sources in irrigation plants  

Microsoft Academic Search

The mechanical power needed for irrigation pumps can be obtained from two renewable sources of energy, wind and sun. In order to investigate the construction costs, the engine performance at various loads and the reliability, two prototypes of Rankine cycle engines using tetrachloroethylene as the working fluid were built, having a power output of about 4 kW. Engine data and

M. Gaia; E. Macchi

1978-01-01

98

Halogenated Hydrocarbons in New Orleans Drinking Water and Blood Plasma  

Microsoft Academic Search

Volatile organics from New Orleans drinking water and pooled plasma were collected on a solid phenyl ether polymer and analyzed by gas chromatographic and mass spectrometric techniques. Thirteen halogenated hydrocarbons were identified in the drinking water. Five halogenated compounds were found in the plasma. Tetrachloroethylene and carbon tetrachloride were found in both the plasma and the drinking water. Considerable variation

Betty Dowty; Douglas Carlisle; John L. Laseter; James Storer

1975-01-01

99

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...

100

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 45Ā°C....

101

Anaerobic biotransformations of pollutant chemicals in aquifers  

Microsoft Academic Search

Summary Anaerobic microbial communities sampled from either a methanogenic or sulfate-reducing aquifer site have been tested for their ability to degrade a variety of groundwater pollutants, including halogenated aromatic compounds, simple alkyl phenols and tetrachloroethylene. The haloaromatic chemicals were biodegraded in methanogenic incubations but not under sulfate-reducing conditions. The primary degradative event was typically the reductive removal of the aryl

Joseph M. Suflita; Susan A. Gibson; Ralph E. Beeman

1988-01-01

102

PULSED AIR SPARGING IN AQUIFERS CONTAMINATED WITH DENSE NONAQUEOUS PHASE LIQUIDS  

EPA Science Inventory

Air sparging was evaluated for remediation of tetrachloroethylene (PCE) present as dense nonaqueous phase liquid (DNAPL) in aquifers. A two-dimensional laboratory tank with a transparent front wall allowed for visual observation of DNAPL mobilization. A DNAPL zone 50 cm high was ...

103

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 ā??airing...

104

Volatilization of Binary Nonaqueous Phase Liquid Mixtures in Unsaturated Porous Media  

Microsoft Academic Search

nitude below their volatility and solubility values and, thus, NAPLs are of great environmental concern. This study examines the volatilization behavior of binary nonaque- Soil vapor extraction (SVE) and bioventing (BV) ous phase liquid (NAPL) mixtures consisting of styrene, and toluene have emerged as attractive in situ remediation technolo- or tetrachloroethylene (PCE). Residual NAPL saturations were em- placed in unsaturated

Linda M. Abriola; Scott A. Bradford; John Lang; Charles L. Gaither

2004-01-01

105

In vivo exposure of female rats to toxicants may affect oocyte quality.  

PubMed

A potential endpoint for female reproductive toxicants is fertilizability of the oocytes. This endpoint has not been adequately examined for mammalian females. The objective of these studies was to evaluate fertilizability of rat oocytes following in vivo exposure to known male reproductive toxicants that exert effects via pathways that do not include endocrine disruption and to 4-vinylcyclohexene diepoxide, known to interfere with early follicular development. Oocytes were obtained from females following exposure and quality assessed by in vitro fertilization rate. One study evaluated fertilizability following 2 weeks exposure of females to inhaled tetrachloroethylene (2h/day, 5 days/week). The remaining studies evaluated fertilizability immediately following 2 weeks exposure via drinking water to tetrachloroethylene, trichloroethylene, the fuel oxidants methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), and a metabolite of the first two ethers 2-methyl-1,2-propanediol (2M2P), and to 4-vinylcyclohexene diepoxide. The percentage of oocytes fertilized was reduced following inhalation exposure to tetrachloroethylene, or consumption of trichloroethylene or TAME. Fertilizability was not altered by exposures to the other reproductive toxicants or to the other fuel oxidants. Consistent with the reduced oocyte fertilizability following exposure to trichloroethylene, oocytes from exposed females had a reduced ability to bind sperm plasma membrane proteins. Female reproductive capability assessed by the endpoint, oocyte fertilizability, was reduced by exposure to trichloroethylene and inhaled tetrachloroethylene. PMID:12759095

Berger, Trish; Horner, Catherine M

106

Cocaine detection by a mid-infrared waveguide integrated with a microfluidic chip.  

PubMed

A germanium (Ge) strip waveguide on a silicon (Si) substrate is integrated with a microfluidic chip to detect cocaine in tetrachloroethylene (PCE) solutions. In the evanescent field of the waveguide, cocaine absorbs the light near 5.8 ?m, which is emitted from a quantum cascade laser. This device is ideal for (bio-)chemical sensing applications. PMID:22806146

Chang, Yu-Chi; Wägli, Philip; Paeder, Vincent; Homsy, Alexandra; Hvozdara, Lubos; van der Wal, Peter; Di Francesco, Joab; de Rooij, Nico F; Peter Herzig, Hans

2012-07-18

107

Test plan for single well injection\\/extraction characterization of DNAPL  

Microsoft Academic Search

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

B. B. Looney; K. M. Jerome; S. Burdick; J. Rossabi; T. R. Jarosch; C. A. Eddy-Dilek

1995-01-01

108

Test plan for Geo-Cleanse{reg_sign} demonstration (in situ destruction of dense non-aqueous phase liquid (DNAPL))  

Microsoft Academic Search

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

K. M. Jerome; B. B. Looney; F. Accorsi; M. Dingens; J. T. Wilson

1996-01-01

109

Historical review on development of environmental quality standards and guideline values for air pollutants in Japan  

Microsoft Academic Search

Environmental quality standards (EQSs) have been established as desirable levels to be maintained for protection of human health and the conservation of the living environment by Basic Environment Law. EQSs in ambient air had been set for 10 substances (sulfur dioxide (SO2), carbon monoxide (CO), suspended particulate matter (SPM), nitrogen dioxide (NO2) and photochemical oxidants (Ox), benzene, tetrachloroethylene, trichloroethylene, dioxins

Toshihiro Kawamoto; Thi-Thu-Phuong Pham; Takayuki Matsuda; Tsunehiro Oyama; Masayuki Tanaka; Hsu-Sheng Yu; Iwao Uchiyama

2011-01-01

110

Removal of four kinds of volatile organic compounds mixture in air using silent discharge reactor driven by bipolar pulsed power  

Microsoft Academic Search

A silent discharge reactor initiated by bipolar pulsed power substituting the traditional ac power was used to remove the volatile organic compounds (VOCs) mixture of acetone, benzene, tetrachloroethylene and m-xylene. The results indicated that the silent discharge driven by bipolar pulsed power could effectively input pulsed energy, produce strong instant discharge and energetic particles, and thus enhance the removal efficiency

Hongchang Wang; Duan Li; Yan Wu; Jie Li; Guofeng Li

2009-01-01

111

Volatile chlorinated organic compound levels in rain water from Kobe City in Japan  

Microsoft Academic Search

Water pollution by volatile chlorinated organic compounds has become a serious environmental problem. The Environmental Agency of Japan has defined the regulations on trichloroethylene, tetrachloroethylene, 1,1,1-trichloroethane and carbon tetrachloride in wastewater in 1989. In order to protect against water pollution, it is important to keep concentrations in these compounds in environmental water as low as possible. Therefore, the determination of

Atsuko Adachi; Tadashi Kobayashi

1994-01-01

112

SYNERGISTIC AND ANTAGONISTIC EFFECTS ON GENOTOXICITY OF CHEMICALS COMMONLY FOUND IN HAZARDOUS WASTE SITES  

EPA Science Inventory

Synergistic and antagonistic effects on genotoxicity of mixtures of four chemicals; i.e., lead tetraacetate (LTA), arsenic trioxide (ATO), dieldrin (DED), and tetrachloroethylene (TCE), were evaluated by the Tradescantia-Micronucleus (Trad-MCN) assay. he concentration of stock so...

113

Synthesis and Application of Carbon-Iron Oxide Microspheres' Black Pigments in Electrophoretic Displays  

NASA Astrophysics Data System (ADS)

Carbon-iron oxide microspheres’ black pigments (CIOMBs) had been prepared via ultrasonic spray pyrolysis of aqueous solutions containing ferrous chloride and glucose. Due to the presence of carbon, CIOMBs not only exhibited remarkably acid resistance, but also could be well dispersed in both polar solvents and nonpolar solvent. Finally, dispersions of hollow CIOMBs in tetrachloroethylene had successfully been applied in electrophoretic displays.

Meng, Xianwei; Wen, Ting; Sun, Shiwei; Zheng, Rongbo; Ren, Jun; Tang, Fangqiong

2010-10-01

114

Appraisal of ground-water quality in the Bunker Hill basin of San Bernardino Valley, California  

Microsoft Academic Search

Water samples were collected from 47 wells and analyzed for concentration of major inorganic ions, nitrogen species, and volatile (purgeable) organic priority pollutants to assess groundwater quality in the Bunker Hill basin, California. Data were supplemented with additional analysis of nitrate, tetrachloroethylene, and trichloroethylene made by other agencies. The organic quality of groundwater in the basin generally is suitable for

L. F. W. Duell; R. A. Schroeder

1989-01-01

115

Synthesis and Application of Carbon-Iron Oxide Microspheres' Black Pigments in Electrophoretic Displays  

PubMed Central

Carbon–iron oxide microspheres’ black pigments (CIOMBs) had been prepared via ultrasonic spray pyrolysis of aqueous solutions containing ferrous chloride and glucose. Due to the presence of carbon, CIOMBs not only exhibited remarkably acid resistance, but also could be well dispersed in both polar solvents and nonpolar solvent. Finally, dispersions of hollow CIOMBs in tetrachloroethylene had successfully been applied in electrophoretic displays.

2010-01-01

116

Using vertical circulation wells for partitioning tracer tests and remediation of DNAPLs  

Microsoft Academic Search

Two different vertical circulation well (VCW) systems (Type A and Type B) were used to detect and subsequently remove tetrachloroethylene (PCE) spilled in a three-dimensional sand tank. The Type A system has one injection interval and one extraction interval. The Type B system has two injection intervals separated by an intermediate extraction interval. PCE was detected through partitioning tracer tests

L. Chen; R. C. Knox

1997-01-01

117

Entrapment and dissolution of DNAPLs in heterogeneous porous media  

Microsoft Academic Search

Two-dimensional multiphase flow and transport simulators were refined and used to numerically investigate the entrapment and dissolution behavior of tetrachloroethylene (PCE) in heterogeneous porous media containing spatial variations in wettability. Measured hydraulic properties, residual saturations, and dissolution parameters were employed in these simulations. Entrapment was quantified using experimentally verified hydraulic property and residual saturation models that account for hysteresis and

Scott A Bradford; Klaus M Rathfelder; John Lang; Linda M Abriola

2003-01-01

118

A pore-scale investigation of mass transport from dissolving DNAPL droplets  

Microsoft Academic Search

Spheres and pendular rings of trichloroethylene and tetrachloroethylene are observed dissolving in an artificial porous medium consisting of a single layer of glass beads. Given the simple geometry of the droplets, pore-scale mass transfer coefficients are calculated. For dissolving spheres, mass transfer coefficients are found to be constant over time. However, coefficients for pendular rings are found to decrease as

Christopher A. Kennedy; William C. Lennox

1997-01-01

119

Field demonstration of surfactant-enhanced solubilization of DNAPL at Dover Air Force Base, Delaware  

Microsoft Academic Search

This study reports on a surfactant-based flood for tetrachloroethylene (PCE) removal from a control test cell at the Dover National Test Site. The surfactant formulation (sodium dihexyl sulfosuccinate (Aerosol-MA® or AMA), isopropanol and calcium chloride) was able to achieve a high concentration of PCE in swollen micelles (supersolubilization) without vertical PCE migration. The hydraulic system included eight screened wells that

Jeffrey Childs; Edgar Acosta; Michael D. Annable; Michael C. Brooks; Carl G. Enfield; Jeffrey H. Harwell; Mark Hasegawa; Robert C. Knox; P. Suresh C. Rao; David A. Sabatini; Ben Shiau; Erika Szekeres; A. Lynn Wood

2006-01-01

120

Observed migration of a controlled DNAPL release by geophysical methods  

Microsoft Academic Search

Seven hundred seventy liters of a dense nonaqueous phase liquid (DNAPL), tetrachloroethylene (PCE), were released into an isolated volume of a completely saturated natural sandy aquifer. The release was monitored over a period of 984 hours with a variety of geophysical methods including ground penetrating radar, time domain reflectometry, in situ resistivity, and a neutron soil moisture probe. The PCE

M. L. Brewster; A. P. Annan; J. P. Greenhouse; J. D. Redman; B. H. Kueper; G. R. Olhoeft; K. A. Sander

1995-01-01

121

Influence of viscous, gravitational, and capillary forces on DNAPL saturation  

Microsoft Academic Search

Four dense nonaqueous phase liquids (DNAPLs) -- bromoform, chlorobenzene, tetrachloroethylene, and trichloroethylene -- were used to investigate the influence of viscous, gravitational, and capillary forces on DNAPL saturation in a natural aquifer sand. The relative magnitudes of these forces are expressed in terms of two dimensionless groups, the Capillary Number (N{sub Ca}), defined as the ratio of the viscous force

Helen E. Dawson; Paul V. Roberts

1997-01-01

122

Synthesis of functional microcapsules containing suspensions responsive to electric fields  

Microsoft Academic Search

A sort of functional microcapsules, which contain a suspension responsive to electric fields, is prepared by in situ polymerization of urea and formaldehyde. The suspension is made up of pigment phthalocyanine green (PPG) and tetrachloroethylene. In order to solve the particles' separation from the suspension during the microencapsulation and to obtain microcapsules applying to electronic ink display, the dispersibility of

Huilin Guo; Xiaopeng Zhao; Jianping Wang

2005-01-01

123

Critical contaminant/critical pathway analysis - surface water transport for nonradioactive contaminants  

SciTech Connect

The health risks for an individual exposed to contaminants released from SRS outfalls from 1989 to 1995 were estimated. The exposure pathways studied are ingestion of drinking water, ingestion of contaminated fish and dermal contact with contaminants in water while swimming. The estimated incremental risks for an individual developing cancer vary from 3.E-06 to 1.0E-05. The estimated total exposure chronic noncancer hazard indices vary from 6.E-02 to 1.E-01. The critical contaminants were ranked based on their cancer risks and chronic noncarcinogenic hazard quotients. For cancer risks, the critical contaminants released from SRS outfalls are arsenic, tetrachloroethylene, and benzene. For chronic noncarcinogenic risks, the critical contaminants released from srs outfalls are cadmium, arsenic, silver, chromium, mercury, selenium, nitrate, manganese, zinc, nickel, uranium, barium, copper, tetrachloroethylene, cyanide, and phenol. The critical pathways in decreasing risk order are ingestion of contaminated fish, ingestion of drinking water and dermal contact with contaminants in water while swimming.

Chen, Kuo-Fu

1996-11-01

124

Permanganate oxidation of DNAPL in a large 3-D flow tank  

Microsoft Academic Search

Potassium permanganate (KMnO4), as a metal-oxo reagent, can attack a double carbon-carbon bond and therefore oxidize common chlorinated ethylenes, such as trichloroethylene (TCE) and tetrachloroethylene (PCE). This feature of metal-oxo reagents facilitates the use of permanganate to remediation of chlorinated solvents in soil and groundwater. In this study, we evaluated the efficiency of TCE removal by permanganate oxidation in large

E. Lee; Y. Seol; Y. C. Fang; F. W. Schwartz

2002-01-01

125

Advanced Oxidation Processes for Treating Groundwater Contaminated With TCE and PCE: Laboratory Studies  

Microsoft Academic Search

Oxidation of trichloroethylene (TCE) and tetrachloroethylene (PCE) with various dosages of ozone or ozone plus hydrogen peroxide was studied in laboratory experiments. The results show that hydrogen peroxide accelerates the oxidation of TCE and PCE by ozone. At peroxide-to-ozone dosage ratios of > 0.7 (w\\/w), the process appears to be mass transfer limited. High levels of bicarbonate ion in the

William H. Glaze; Joon-Wun Kang

1988-01-01

126

Localized scleroderma after exposure to organic solvents.  

PubMed

A 26-year-old female developed plaques characteristic of morphea on the volar surfaces of the forearms and on the dorsal surfaces on the ankles following an exposure to trichloroethylene, tetrachloroethylene and other solvents by inhalation. Exposure to chemicals has been known to be important as a provoking factor of systemic sclerosis. This patient shows that exposure to solvents could provoke localized scleroderma. PMID:7873829

Czirjįk, L; Pócs, E; Szegedi, G

1994-01-01

127

Infiltration of PCE in a system containing spatial wettability variations  

Microsoft Academic Search

Abstract A two-dimensional infiltration experiment was conducted to investigate and quantify the effect of spatial wettability variations on DNAPL migration and entrapment in saturated sands. Experimental observations of tetrachloroethylene (PCE) infiltration showed,that organic-wet sand lenses acted as very effective capillary barriers, retaining PCE and inhibiting its downward migration. A multiphase numerical,simulator was,used to model,this sand box,experiment. The simulator incorporates wettability-modified

Denis M. O'Carroll; Scott A. Bradford; Linda M. Abriola

128

Genotoxic effects of chemicals in the single cell gel (SCG) test with human blood cells in relation to the induction of sister-chromatid exchanges (SCE)  

Microsoft Academic Search

In a comparative study, henzo[a]pyrene (BaP), cyclophosphamide (CP), N-methyl-N?-nitro-N-nitrosoguanidine (MNNG) and tetrachloroethylene (PER) were tested for their ability to induce genotoxic effects in the single cell gel (SCG) test and the sister-chromatid exchange (SCE) test with human blood cells. MNNG as well as S9 mix activated BaP- and CP-induced DNA effects in both tests in a dose-dependent manner. While the

Andreas Hartmann; Günter Speit

1995-01-01

129

Aerobic microorganism for the degradation of chlorinated aliphatic hydrocarbons  

DOEpatents

A chlorinated aliphatic hydrocarbon-degrading microorganism, having American Type Culture Collection accession numbers ATCC 53570 and 53571, in a biologically pure culture aseptically collected from a deep subsurface habitat and enhanced, mineralizes trichloroethylene and tetrachloroethylene to HCl, H.sub.2 O and Co.sub.2 under aerobic conditions stimulated by methane, acetate, methanol, tryptone-yeast extract, propane and propane-methane.

Fliermans, Carl B. (Augusta, GA)

1989-01-01

130

Comparing the transport of some organic micro-pollutants in a soil-groundwat er system by means of a mathematical model  

Microsoft Academic Search

A mathematical model is applied to simulate the infiltration-induced vertical transport of organic micro-pollutants (benzo-(a)pyrene, y-hexachlorocyclohexane, tetrachloroethylene) in a soil-groundwater system. The one-dimensional model uses finite element methods to describe the simultaneous transport of water and dissolved species under saturated-unsaturated conditions in nonhomogeneou s soil profiles, including adsorption and decay. Physical and chemical data for three types of soil, as

W. DURNER; R. HERRMANN

1990-01-01

131

EXTRACTION OF AMERICIUM(III) FROM CHLORIDE MEDIA BY OCTYL(PHENYL)-N,N-DIISOBUTYLCARBAMOYLMETHYLPHOSPHINE OXIDE  

Microsoft Academic Search

The extraction of Am(III) from chloride media was studied using octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide, O? D(iB)CMPO or CMPO, dissolved in tetrachloroethylene. Although the extraction of Am(III) by 0?D(iB)CMPO is many orders of magnitude weaker from chloride than nitrate media, the rapid Increase in the mean activity of chloride in HC1 and in most soluble chloride salts with concentration makes extraction from moderate

E. Philip Horwitz; Herbert Diamond; Kathleen A. Martin; Renato Chiarizia

1987-01-01

132

Korean Water Quality Standards for the Protection of Human Health and Aquatic Life  

Microsoft Academic Search

The Korean water quality standards (WQS) for the protection of human health have recently been expanded. The main reason for the expansion was to address the concern of increasing hazardous pollutants in water environments. A risk-based approach was used to derive the WQS for eight toxic substances including antimony, benzene, carbon tetrachloride, chloroform 1,2-dichloroethane, dichlromethane, diethylhexylphtalate, and tetrachloroethylene. Same methodology

Youn-Joo An; Jae-Kwan Lee; Soon Cho

133

Reactive hydro- end chlorocarbons in the troposphere and lower stratosphere : sources, distributions, and chemical impact  

Microsoft Academic Search

The work presented in this thesis focuses on measurements of chemical reactive C2 C7 non-methane hydrocarbons (NMHC) and C1 C2 chlorocarbons with atmospheric lifetimes of a few hours up to about a year. The group of reactive chlorocarbons includes the most abundant atmospheric species with large natural sources, which are chloromethane (CH3Cl), dichloromethane (CH2Cl2), and trichloromethane (CHCl3), and tetrachloroethylene (C2Cl4)

H. A. Scheeren

2003-01-01

134

Systematic selection of off-gas treatment at the Savannah River Site  

Microsoft Academic Search

At the Savannah River Site (SRS), from 1958--1985, effluent waste from the reactor fuel and target rod fabrication area (M-Area) was discharged to a settling basin. In 1981, monitoring wells detected groundwater contamination, specifically trichloroethylene and tetrachloroethylene, in the immediate vicinity of the basin. Under the auspices of Resource Conservation and Recovery Act (RCRA) the M-Area contamination must be addressed

S. T. McKillip; T. E. Rehder

1992-01-01

135

Evaluating an AOP for TCE and PCE removal  

Microsoft Academic Search

A full-scale evaluation of an advanced oxidation process (AOP) involving the use of ozone (O?) and hydrogen peroxide (H?O?) at a 126-L\\/s (2,000-gpm) flow rate was completed in a plug-flow hydraulic regime by the Los Angeles (Calif.) Department of Water and Power. This facility is the first full-scale AOP for trichloroethylene (TCE) and tetrachloroethylene (PCE) treatment in the United States,

Ali A. Karimi; Jeremy A. Redman; William H. Glaze; Gary F. Stolarik

1997-01-01

136

Abiotic reductive dechlorination of chlorinated ethylenes by iron-bearing phyllosilicates  

Microsoft Academic Search

Abiotic reductive dechlorination of chlorinated ethylenes (tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (c-DCE), and vinylchloride (VC)) by iron-bearing phyllosilicates (biotite, vermiculite, and montmorillonite) was characterized to obtain better understanding of the behavior of these contaminants in systems undergoing remediation by natural attenuation and redox manipulation. Batch experiments were conducted to evaluate dechlorination kinetics and some experiments were conducted with addition of

Woojin Lee; Bill Batchelor

2004-01-01

137

Health assessment for Northside Landfill, Spokane, Washington, Region 10. CERCLIS No. WAD980511778. Final report  

SciTech Connect

The North Landfill site is located northwest of Spokane, Washington, approximately one-half mile east of the Spokane River. The contaminants found on the site are tetrachloroethylene, trichloroethylene, 1,1,1-trichloroethane, and 1,1-dichloroethane. The contamination in the ground water is of potential concern if the water from affected wells is used for domestic purposes. All affected residents should be supplied an alternate source of water for all uses including bathing and irrigation of gardens and lawns.

Not Available

1988-04-01

138

Solvent release into a sandy aquifer. 1: Overview of source distribution and dissolution behavior  

Microsoft Academic Search

This paper describes some of the results from a field experiment at the Canadian Forces Base Borden, Ontario, Canada. Five liters of a chlorinated solvent mixture (2.0 L of trichloroethylene, 0.5 L of chloroform, and 2.5 L of tetrachloroethylene) was released into a sandy aquifer to create a heterogeneously distributed source. The dissolution and dissolved-phase plume development from this source

Kim Broholm; Stanley Feenstra; John A. Cherry

1999-01-01

139

Modification of the Standard Neutral Ozone Decomposition Model  

Microsoft Academic Search

The modified Staehelin, Buhler, and Hoigné model for aqueous ozone decomposition was tested over a wide range of hydroxyl radical scavenger concentrations at a pH of 7.1–7.2. Results from these experiments showed that the modified model appeared to underpredict the residual ozone concentration and overpredict the residual hydroxyl radical probe compound, tetrachloroethylene, concentration. The modified Staehelin, Buhler, and Hoigné model

Boijayanta K. Bezbarua; David A. Reckhow

2004-01-01

140

A method for the rapid dechlorination of low molecular weight chlorinated hydrocarbons in water  

Microsoft Academic Search

1,1,2-Trichloroethylene (TCE), 1,1-dichloroethylene, cis and trans-1,2-dichloroethylene and tetrachloroethylene (PCE), at concentrations of 20 ppm in aqueous solutions were rapidly hydrodechlorinated to ethane (in a few minutes), on the surface of palladized iron in batch experiments that were performed in closed vials. No intermediate reaction products such as 1,1-dichloroethylene, 1,2-dichloroethylenes and vinyl chloride were detected at concentrations > 1 ppm either

Rosy Muftikian; Quintus Fernando; Nic Korte

1995-01-01

141

Reductive dechlorination catalyzed by bacterial transition-metal coenzymes  

Microsoft Academic Search

The bacterial transition-metal coenzymes vitamin Bāā (Co), coenzyme Fāāā (ni), and hematin (Fe) catalyzed the reductive dechlorination of polychlorinated ethylenes and benzenes, whereas the electron-transfer proteins four-iron ferredoxin, two-iron ferredoxin, and azurin (Cu) did not. For vitamin Bāā and coenzyme Fāāā, reductive dechlorination rates for different classes of perchlorinated compounds had the following order: carbon tetrachloride > tetrachloroethylene > hexachlorobenzene.

Charles J. Gantzer; Lawrence P. Wackett

1991-01-01

142

Toxicity potential of compounds found in parenteral solutions with rubber stoppers  

Microsoft Academic Search

Leached stopper components found in parenteral solutions produced by several manufacturers were identified and quantitated. Their toxicity potential was determined by comparing the types and quantities of the leached components with known toxicity levels and\\/or harmful effects. Toxicity potentials for benzaldehyde, 2-butoxyethanol, cyclohexanone, ethylbenzene, 1,1,2,2-tetrachloroethane, and tetrachloroethylene are listed. Breakdown products of dextrose (furfural and 5-hydroxymethylfurfural), which may also have

Danielson

1992-01-01

143

Experimental Results on the Destruction of PCE using a PhotoChemical Remediation Reactor  

Microsoft Academic Search

A vapor-phase tetrachloroethylene (PCE) destruction experiment using a newly constructed photo-chemical remediation (PCR) reactor is performed. One of the applications for the PCR reactor is subsurface remediation of volatile organic compounds (VOCs). Ultraviolet (UV) light, when emitted at an effective absorption frequency (primary wavelengths of 185 and 254 nm), cleaves a VOC's carbon-chlorine bond thus reducing harmful contaminants to harmless

J. J. Lee; K. Y. Lee; J. R. Stencel; J. Khinast

2001-01-01

144

Synthesis and Application of Carbon–Iron Oxide Microspheres’ Black Pigments in Electrophoretic Displays  

Microsoft Academic Search

Carbon–iron oxide microspheres’ black pigments (CIOMBs) had been prepared via ultrasonic spray pyrolysis of aqueous solutions\\u000a containing ferrous chloride and glucose. Due to the presence of carbon, CIOMBs not only exhibited remarkably acid resistance,\\u000a but also could be well dispersed in both polar solvents and nonpolar solvent. Finally, dispersions of hollow CIOMBs in tetrachloroethylene\\u000a had successfully been applied in electrophoretic

Xianwei Meng; Ting Wen; Shiwei Sun; Rongbo Zheng; Jun Ren; Fangqiong Tang

2010-01-01

145

H-Area Seepage Basins groundwater monitoring report. Second quarter 1992  

SciTech Connect

During second quarter 1992, tritium, nitrate, nonvolatile beta, total alpha-emitting radium (radium-224 and radium-226), gross alpha, mercury, lead, tetrachloroethylene, arsenic, and cadmium exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the H-Area Seepage Basins (HASB) at the Savannah River Plant. This report gives the results of the analyses of groundwater from the H-Area Seepage Basin.

Not Available

1992-09-01

146

H-Area Seepage Basins groundwater monitoring report  

SciTech Connect

During second quarter 1992, tritium, nitrate, nonvolatile beta, total alpha-emitting radium (radium-224 and radium-226), gross alpha, mercury, lead, tetrachloroethylene, arsenic, and cadmium exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the H-Area Seepage Basins (HASB) at the Savannah River Plant. This report gives the results of the analyses of groundwater from the H-Area Seepage Basin.

Not Available

1992-09-01

147

Toxicity potential of compounds found in parenteral solutions with rubber stoppers  

SciTech Connect

Leached stopper components found in parenteral solutions produced by several manufacturers were identified and quantitated. Their toxicity potential was determined by comparing the types and quantities of the leached components with known toxicity levels and/or harmful effects. Toxicity potentials for benzaldehyde, 2-butoxyethanol, cyclohexanone, ethylbenzene, 1,1,2,2-tetrachloroethane, and tetrachloroethylene are listed. Breakdown products of dextrose (furfural and 5-hydroxymethylfurfural), which may also have harmful effects, were quantitated.

Danielson, J.W. (Sterility Analysis Research Center, Food and Drug Administration, Minneapolis, MI (United States))

1992-03-01

148

Adsorption of Polypropylene and Polyethylene on Liquid Chromatographic Column Packings  

Microsoft Academic Search

A group of zeolites and a 3D nanoporous metal-organic material RPM-1 were tested as column packings for adsorption of isotactic polypropylene and linear polyethylene from dilute solutions. It was found that polyethylene is fully or partially retained from thermodynamically good solvents (1,1,2,2-tetrachloroethylene, 1,4-dimethylbenzene, diphenylether, 1,2-dichlorobenzene and 1,3-dichlorobenzene) at temperatures of 115 °C or 140 °C, when a specific type of

T. Macko; J. F. Denayer; H. Pasch; L. Pan; J. Li; A. Raphael

2004-01-01

149

Catalytic hydrodehalogenation of chlorinated ethylenes using palladium and hydrogen for the treatment of contaminated water  

Microsoft Academic Search

A kinetic model is presented for the catalytic hydrodehalogenation of chlorinated ethylenes using Pd and H2 under water treatment conditions. All five chlorinated ethylenes, including tetrachloroethylene (PCE) and vinyl chloride, were completely removed from tap water within 10 minutes at room temperature by 0.5 g of 0.5% Pd on alumina and 0.1 atm H2. Ethane accounted for 55–85% of the

Cindy G. Schreier; Martin Reinhard

1995-01-01

150

Clastogenicity evaluation of seven chemicals commonly found at hazardous industrial-waste sites  

SciTech Connect

Seven chemicals commonly found at industrial waste sites were tested with the Tradescantia-micronucleus (Trad-MCN) assay to evaluate their clastogenic potential. They were: Aldrin, arsenic trioxide, 1,2-benz(a,h)anthracene, dieldrin, heptachlor, lead tetraacetate, and tetrachloroethylene. Results of repeated tests for clastogenicity yielded the minimum effective dose (MED) of 0.44 ppm for lead tetraacetate, 3.81 ppm for dieldrin, and 1.88 ppm for heptachlor. Arsenic trioxide and 1,2-benz(a,h)anthracene yielded positive responses at the MED of 3.96 ppm and 2.28 ppm, respectively. Aldrin and tetrachloroethylene were considered to be immiscible with water, and the test yielded negative responses. Results of tetrachloroethylene fume treatment yielded a positive response at the MED of 30 ppm/min in 2-hr exposures. Five chemicals determined to be clastogens by the test were ranked according to their MED in the descending order of potency as follows: Lead tetraacetate, heptachlor, 1,2-benz(a,h)anthracene, dieldrin, and arsenic trioxide. Results of the study indicate that Trad-MCN bioassay could be effectively utilized for assessing the genetic hazard from the leachates and volatile compounds emanating from uncontrolled industrial waste sites.

Sandhu, S.S.; Ma, T.H.; Peng, Y.; Zhou, X.

1989-01-01

151

Cytogenetic analysis of an exposed-referent study: perchloroethylene-exposed dry cleaners compared to unexposed laundry workers  

Microsoft Academic Search

Background  Significant numbers of people are exposed to tetrachloroethylene (perchloroethylene, PCE) every year, including workers in\\u000a the dry cleaning industry. Adverse health effects have been associated with PCE exposure. However, investigations of possible\\u000a cumulative cytogenetic damage resulting from PCE exposure are lacking.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Eighteen dry cleaning workers and 18 laundry workers (unexposed controls) provided a peripheral blood sample for cytogenetic\\u000a analysis by

James D Tucker; Karen J Sorensen; Avima M Ruder; Lauralynn Taylor McKernan; Christy L Forrester; Mary Ann Butler

2011-01-01

152

Spectrum of the reductive dehalogenation activity of Desulfitobacterium frappieri PCP-1  

SciTech Connect

Desulfitobacterium frappieri PCP-1 was induced for ortho- and para-dechlorinating activities by different chlorophenols. Dehalogenation rates ranging from 25 to 1,158 nmol/min/mg of cell protein were observed according to the chlorophenol tested and the position of the chlorine removed. D. frappieri shows a broad substrate specificity; in addition to tetrachloroethylene and pentachloropyridine, strain PCP-1 can dehalogenate at ortho, meta, and para positions a large variety of aromatic molecules with substituted hydroxyl or amino groups. Reactions of O demethylation and reduction of nitro to amino substituents on aromatic molecules were also observed.

Dennie, D.; Gladu, I.; Lepine, F.; Villemur, R.; Bisaillon, J.G.; Beaudet, R. [Univ. du Quebec, Ville de Laval, Quebec (Canada). Centre de Recherche en Microbiologie Appliquee

1998-11-01

153

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

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.

Hazen, T.C.

1991-09-18

154

Health assessment for Gentle Cleaners, Inc. /Granite Knitting Mill, Inc. , Souderton, Pennsylvania, Region 3. CERCLIS No. PAD096834494. Preliminary report  

SciTech Connect

The Gentle Cleans, Inc./Granite Knitting Mills, Inc. site is on the National Priorities List. Both facilities are still in operation. A plume of contaminated groundwater has been identified within the general vicinity of the site. The contaminants of concern are those volatile organic compounds typically used in the dry cleaning industries: tetrachloroethylene, 1,1-dichloroethylene, trichloroethylene, 1,2-dichloroethylene, carbon tetrachloride, and chloroform. A municipal well and a domestic well near the site were contaminated with perchloroethylene. The site is considered to be of public health concern because of the risk to human health caused by the likelihood of exposure to hazardous substances via volatile organic compounds in groundwater.

Not Available

1988-06-29

155

Soil Vapor Extraction of PCE/TCE Contaminated Soil  

SciTech Connect

The A/M Area of the Savannah River Site soil and groundwater is contaminated with tetrachloroethylene (PCE) and trichloroethylene (TCE). Contamination is the result of previous waste disposal practices, once considered state-of-the-art. Soil Vapor Extraction (SVE) units have been installed to remediate the A/M Area vadose zone. SVE is a proven in-situ method for removing volatile organics from a soil matrix with minimal site disturbance. SVE alleviates the infiltration of contaminants into the groundwater and reduces the total time required for groundwater remediation. Lessons learned and optimization of the SVE units are also discussed.

Bradley, J.M. [Westinghouse Savannah River Company, AIKEN, SC (United States); Morgenstern, M.R. [Bechtel, , ()

1998-08-01

156

Occupational exposure limits based on biological monitoring: the Japan Society for Occupational Health  

Microsoft Academic Search

The Japan Society for Occupational Health started to recommend an occupational exposure limit based on biological monitoring\\u000a (OEL-B) in 1993. Up to 1998, OEL-Bs for mercury, lead, hexane and 3,3?-dichloro-4,4?-diaminodiphenylmethane had been adopted\\u000a and those for 17 chemical substances (arsenic, cadmium, chromium, nickel, acetone, methanol, benzene, toluene, xylene, styrene,\\u000a tetrachloroethylene, trichloroethylene, N,N-dimethylacetoamide, N,N-dimethylformamide,carbon disulfide, carbon monoxide, and organophospate insecticides) are

K. Omae; T. Takebayashi; H. Sakurai

1999-01-01

157

Evidence for existence in human tissues of monomers for plastics and rubber manufacture.  

PubMed Central

Although exposure to many industrially important monomers is controlled by law, few of these reactive chemicals have been determined in human tissues. Analogy with other fat-soluble organic substances strongly implies that these monomers may be retained in tissue, subject to the usual physiological constraints of metabolism, solubility and volatility. The storage of DDT and PCBs is discussed, as well as tetrachloro-ethylene (PCE) and trichloroethylene (TCE), which are chemically similar to many industrially used monomers. Styrene in blood and breath and its metabolites in urine have been studied in humans. Styrene and vinyl chloride have been measured in fat tissue of polymerization workers.

Wolff, M S

1976-01-01

158

Analysis of C2-C4 peroxyacyl nitrates and C1-C5 alkyl nitrates with a non-polar capillary column.  

PubMed

Analysis of peroxyacetyl nitrate (PAN), peroxypropionyl nitrate, peroxy-n-butyryl nitrate, and peroxyisobutyryl nitrate (PiBN) with a non-polar capillary column indicated PAN not to coelute with PiBN. Isopropyl nitrate coeluted with PAN, n-butyl nitrate with PiBN and ethyl nitrate with chloroform, at oven temperature 30 degrees C. In addition methyl nitrate, n-propyl nitrate, 2-butyl nitrate, 2-methyl-2-butyl nitrate, 3-pentyl nitrate and 2-pentyl nitrate were studied. Their response factors in the electron-capture detector were also determined. Tetrachloroethylene, carbon tetrachloride and chloroform whose vapors occur in the atmosphere were also examined. PMID:11358259

Glavas, S

2001-04-27

159

Supplemental Technical Data Summary M-Area Groundwater Investigation  

SciTech Connect

This supplement to the Preliminary Technical Data Summary (TDS) (Gordon, 1982) presents the state of knowledge on the hydrogeology and contaminant plume characteristics in the vicinity of M Area as of October 1984. As discussed in the previous TDS, the contaminants consist of organic solvents used for metal degreasing, namely trichloroethylene, tetrachloroethylene, and 1,1,1-trichloroethane. Since the issuance of the previous TDS, the groundwater consulting firm of Geraghty & Miller, Inc. has been retained to assist with program strategy, planning, and investigative techniques

Marine, I.W., Bledsoe, H.W. [Westinghouse Savannah River Company, AIKEN, SC (United States)

1995-10-01

160

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

SciTech Connect

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.

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

2006-06-21

161

Mixed Waste Management Facility groundwater monitoring report. Second quarter 1994  

SciTech Connect

Currently, 125 wells monitor groundwater quality in the uppermost aquifer beneath the Mixed Waste Management Facility (MWMF) at the Savannah River Site. Samples from the wells are analyzed for selected heavy metals, indicator parameters, radionuclides, volatile organic compounds, and other constituents. During second quarter 1994, chloroethene (vinyl chloride), 1,1-dichloroethylene, gross alpha, lead, tetrachloroethylene, trichloroethylene, or tritium exceeded final Primary Drinking Water Standards (PDWS) in approximately half of the downgradient wells at the MWMF. Consistent with historical trends, elevated constituent levels were found primarily in Aquifer Zone. As in previous quarters, tritium and trichloroethylene were the most widespread elevated constituents during second quarter 1994. Sixty-two of the 125 monitoring wells contained elevated tritium activities. Trichloroethylene concentrations exceeded the final PDWS in 23 wells. Chloroethene, 1,1-dichloroethylene, lead, and tetrachloroethylene, elevated in one or more wells during second quarter 1994, also occurred in elevated levels during first quarter 1994. These constituents generally were elevated in the same wells during both quarters. Gross alpha, which was not elevated in any well during first quarter 1994, was elevated in one well during second quarter. Copper, mercury, and nonvolatile beta were elevated during first quarter 1994 but not during second quarter.

Chase, J.A.

1994-09-01

162

Mixed Waste Management Facility (MWMF) Groundwater Monitoring Report: Fourth quarter 1991 and 1991 summary  

SciTech Connect

During fourth quarter 1991, tritium, trichloroethylene, tetrachloroethylene, chloroethene (vinyl chloride), total radium, mercury, and lead exceeded the US Environmental Protection Agency primary drinking water standards (PDWS) in groundwater samples from monitoring wells at the Mixed Waste Management Facility (MWMF) and adjacent facilities. Tritium and trichloroethylene were the most widespread contaminants; 55 (49%) wells exhibited elevated tritium activities, and 24 (21%) wells exhibited elevated trichloroethylene concentrations. Tritium and trichloroethylene levels exceeding the PDWS also occurred in several wells in Aquifer Unit IIA (Congaree). Levels of manganese, total organic halogens, nickel, iron, 1,1-dichloroethane, aluminum, nonvolatile beta, and trichlorofluoromethane that exceeded Flag 2 criteria were found in one or more wells beneath the MWMF. Downgradient wells in the three hydrostratigraphic units at the MWMF contained elevated levels of tritium, trichloroethylene, tetrachloroethylene, total radium, chloroethene (vinyl chloride), lead, mercury, manganese, total organic halogens, nickel, iron, 1,1-dichloroethane, aluminum, nonvolatile beta, or trichlorofluoromethane. Groundwater samples from 81 (72%) of the monitoring wells at the MWMF and adjacent facilities contained elevated levels of several contaminants.

Thompson, C.Y.

1992-03-01

163

Partial combustion of electrical insulation fluids: Final report  

SciTech Connect

Recurring fire incidents involving transformers have led to a desire to acquire information about the combustion products that may be generated not only in situations of complete combustion, but also in incidents when limited oxygen is present and combustion is incomplete or partial. This report details some results from investigations designed to identify the products of incomplete combustion of five types of dielectric fluids commonly used in transformers, as alternatives to askarels. These fluids are tetrachloroethylene, trichlorotrifluoroethane, polydimethylsiloxane (silicone fluid), mineral oil, and a high temperature hydrocarbon. The investigation of these fluids was begun with a theoretical study of the thermodynamic equilibrium over a range of temperatures and pressures. The experimental program was carried out in two separate studies, one which involved heating the fluid from room temperature to 1000/sup 0/C and another which used injection into a furnace that was preheated to 1000/sup 0/C. The air level in each chamber was chosen to provide 70% and 30% of the oxygen for stoichiometric total combustion. None of the combustions produced detectable chlorinated or polycyclic aromatic hydrocarbon particulates. Detectable quantities of chlorine and hydrogen chloride were produced from tetrachloroethylene as well as a small amount of dichloroacetylene. Trichlorotrifluoroethane produced a number of fluorocarbon compounds as well as hydrogen fluoride. Silicone fluid produced substantial quantities of a solid material, believed to be silicon dioxide and like the two hydrocarbon fluids, produced several combustible hydrocarbon gases as well as carbon dioxide and carbon monoxide. 9 refs., 19 figs., 12 tabs.

Claiborne, C.C.

1987-07-01

164

Solvent vapour detection with cholesteric liquid crystals--optical and mass-sensitive evaluation of the sensor mechanism.  

PubMed

Cholesteric liquid crystals (CLCs) are used as sensitive coatings for the detection of organic solvent vapours for both polar and non-polar substances. The incorporation of different analyte vapours in the CLC layers disturbs the pitch length which changes the optical properties, i.e., shifting the absorption band. The engulfing of CLCs around non-polar solvent vapours such as tetrahedrofuran (THF), chloroform and tetrachloroethylene is favoured in comparison to polar ones, i.e., methanol and ethanol. Increasing solvent vapour concentrations shift the absorbance maximum to smaller wavelengths, e.g., as observed for THF. Additionally, CLCs have been coated on acoustic devices such as the quartz crystal microbalance (QCM) to measure the frequency shift of analyte samples at similar concentration levels. The mass effect for tetrachloroethylene was about six times higher than chloroform. Thus, optical response can be correlated with intercalation in accordance to mass detection. The mechanical stability was gained by combining CLCs with imprinted polymers. Therefore, pre-concentration of solvent vapours was performed leading to an additional selectivity. PMID:22399912

Mujahid, Adnan; Stathopulos, Helen; Lieberzeit, Peter A; Dickert, Franz L

2010-05-12

165

Use of history science methods in exposure assessment for occupational health studies  

PubMed Central

Aims: To show the power of history science methods for exposure assessment in occupational health studies, using the dry cleaning industry in Denmark around 1970 as the example. Methods: Exposure data and other information on exposure status were searched for in unconventional data sources such as the Danish National Archives, the Danish Royal Library, archives of Statistics Denmark, the National Institute of Occupational Health, Denmark, and the Danish Labor Inspection Agency. Individual census forms were retrieved from the Danish National Archives. Results: It was estimated that in total 3267 persons worked in the dry cleaning industry in Denmark in 1970. They typically worked in small shops with an average size of 3.5 persons. Of these, 2645 persons were considered exposed to solvents as they were dry cleaners or worked very close to the dry cleaning process, while 622 persons were office workers, drivers, etc in shops with 10 or more persons. It was estimated that tetrachloroethylene constituted 85% of the dry cleaning solvent used, and that a shop would normally have two machines using 4.6 tons of tetrachloroethylene annually. Conclusion: The history science methods, including retrieval of material from the Danish National Archives and a thorough search in the Royal Library for publications on dry cleaning, turned out to be a very fruitful approach for collection of exposure data on dry cleaning work in Denmark. The history science methods proved to be a useful supplement to the exposure assessment methods normally applied in epidemiological studies.

Johansen, K; Tinnerberg, H; Lynge, E

2005-01-01

166

Reductive dechlorination catalyzed by bacterial transition-metal coenzymes  

SciTech Connect

The bacterial transition-metal coenzymes vitamin B{sub 12} (Co), coenzyme F{sub 430} (ni), and hematin (Fe) catalyzed the reductive dechlorination of polychlorinated ethylenes and benzenes, whereas the electron-transfer proteins four-iron ferredoxin, two-iron ferredoxin, and azurin (Cu) did not. For vitamin B{sub 12} and coenzyme F{sub 430}, reductive dechlorination rates for different classes of perchlorinated compounds had the following order: carbon tetrachloride > tetrachloroethylene > hexachlorobenzene. For hematin, the order of reductive dechlorination rates was carbon tetrachloride > hexachlorobenzene > tetrachloroethylene. Within each class of compounds, rates of dechlorination decreased with decreasing chlorine content. Regio- and stereospecificity were observed in these reactions. In the reductive dechlorination of trichloroethylene, cis-1,2-dichloroethylene was the predominant product formed with vitamin B{sub 12}, coenzyme F{sub 430}, and hematin. Pentachlorobenzene and pentachlorophenol were each dechlorinated by vitamin B{sub 12} to yield two out of three possible isomeric tetrachlorobenzenes. Similar relative kinetics and dechlorination products have been observed in anaerobic cultures, suggesting a possible role of transition-metal coenzymes in the reductive dechlorination of poly-chlorinated compounds in natural and engineered environments.

Gantzer, C.J.; Wackett, L.P. (Univ. of Minnesota, Navarre (United States))

1991-04-01

167

Henry's law constants and micellar partitioning of volatile organic compounds in surfactant solutions  

SciTech Connect

Partitioning of volatile organic compounds (VOCs) into surfactant micelles affects the apparent vapor-liquid equilibrium of VOCs in surfactant solutions. This partitioning will complicate removal of VOCs from surfactant solutions by standard separation processes. Headspace experiments were performed to quantify the effect of four anionic surfactants and one nonionic surfactant on the Henry's law constants of 1,1,1-trichloroethane, tirchloroethylene, toluene, and tetrachloroethylene at temperatures ranging from 30 to 60 C. Although the Henry's law constant increased markedly with temperature for all solutions, the amount of VOC in micelles relative to that in the extramicellar region was comparatively insensitive to temperature. The effect of adding sodium chloride and isopropyl alcohol as consolutes also was evaluated. Significant partitioning of VOCs into miscelles was observed, with the micellar partitioning coefficient (tendency to partition from water into mecelle) increasing according to the following series: trichloroethane < trichloroethylene < toluene < tetrachloroethylene. The addition of surfactant was capable of reversing the normal sequence observed in Henry's law constants for these four VOCs.

Vane, L.M.; Giroux, E.L.

2000-02-01

168

Impacts of environmental conditions on the sorption of volatile organic compounds onto tire powder.  

PubMed

A series of batch tests were performed and the impacts of environmental conditions and phase change on the sorption of volatile organic compounds (VOCs) were investigated. Benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene were selected as target VOCs. Sorption of VOCs onto tire powder was well demonstrated by a linear-partitioning model. Water-tire partition coefficients of VOCs (not tested in this study) could be estimated using a logarithmic relationship between observed water-tire partition coefficients and octanol-water partition coefficients of the VOCs tested. The target VOCs did not seem to compete with other VOCs significantly when sorbed onto the tire powder for the range of concentrations tested. The influence of environmental conditions, such as pH and ionic strength also did not seem to be significant. Water-tire partition coefficients of benzene, trichloroethylene, tetrachloroethylene, and ethylbenzene decreased as the sorbent dosage increased. However, they showed stable values when the sorbent dosage was greater than 10 g/L. Air-tire partition coefficient could be extrapolated from Henry's law constants and water-tire partition coefficient of VOCs. PMID:17889437

Oh, Dong I; Nam, Kyongphile; Park, Jae W; Khim, Jee H; Kim, Yong K; Kim, Jae Y

2007-08-22

169

Mixed Waste Management Facility (MWMF) groundwater monitoring report, second quarter 1992  

SciTech Connect

During second quarter 1992, tritium, trichloroethylene, tetrachloroethylene, chloroethene, antimony, 1,1-dichloroethylene, lead, nonvolatile beta, radium-228, thorium-228, or total alpha-emitting radium (radium-226 and radium-228) exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the Mixed Waste Management Facility (MWMF) and adjacent facilities. Tritium and trichloroethylene were the most widespread constituents; 55 (48%) of the 115 monitored wells contained elevated tritium activities, and 23 (20%) wells exhibited elevated trichloroethylene concentrations. Sixty-three downgradient wells screened in Aquifer Zone IIB2 (Water Table), Aquifer Zone IIB[sub 2] (Barnwell/McBean), and Aquifer Unit IIA (Congaree) contained concentrations of tritium, trichloroethylene, tetrachloroethylene, chloroethene, antimony, 1,1-dichloroethylene, lead, nonvolatile beta, radium-228, thorium-228, or total alpha-emitting radium that exceeded the PDWS during second quarter 1992. Upgradient wells BGO 1D and 2D and HSB 85A, 85B, and 85C did not contain any constituents that exceeded the PDWS.

Not Available

1992-09-01

170

Mixed Waste Management Facility (MWMF) groundwater monitoring report, second quarter 1992  

SciTech Connect

During second quarter 1992, tritium, trichloroethylene, tetrachloroethylene, chloroethene, antimony, 1,1-dichloroethylene, lead, nonvolatile beta, radium-228, thorium-228, or total alpha-emitting radium (radium-226 and radium-228) exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the Mixed Waste Management Facility (MWMF) and adjacent facilities. Tritium and trichloroethylene were the most widespread constituents; 55 (48%) of the 115 monitored wells contained elevated tritium activities, and 23 (20%) wells exhibited elevated trichloroethylene concentrations. Sixty-three downgradient wells screened in Aquifer Zone IIB2 (Water Table), Aquifer Zone IIB{sub 2} (Barnwell/McBean), and Aquifer Unit IIA (Congaree) contained concentrations of tritium, trichloroethylene, tetrachloroethylene, chloroethene, antimony, 1,1-dichloroethylene, lead, nonvolatile beta, radium-228, thorium-228, or total alpha-emitting radium that exceeded the PDWS during second quarter 1992. Upgradient wells BGO 1D and 2D and HSB 85A, 85B, and 85C did not contain any constituents that exceeded the PDWS.

Not Available

1992-09-01

171

Health risk assessment of exposure to selected volatile organic compounds emitted from an integrated iron and steel plant.  

PubMed

Workplace air samples from sintering, cokemaking, and hot and cold forming processes in the integrated iron and steel industry were analyzed to determine their volatile organic compound (VOC) concentration. Sixteen VOC species including three paraffins (cyclohexane, n-hexane, methylcyclohexane), five chlorinated VOC species (trichloroethylene, 1,1,1-trichloroethane, tetrachloroethylene, chlorobenzene, 1,4-dichlorobenzene), and eight aromatics (benzene, ethylbenzene, styrene, toluene, m,p-xylene, o-xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene) were selected to measure their noncancer risk for workers. Concentrations of toluene, xylene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, dichlorobenzene, and trichloroethylene were high in all four processes. Carbon tetrachloride and tetrachloroethylene concentrations were high in the hot and cold forming processes. The noncancer risk followed the increasing order: cokemaking > sintering > hot forming > cold forming. 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene contributed 44% to 65% and 13% to 20% of noncancer risk, respectively, for the four processes. Benzene accounted for a high portion of the noncancer risk in cokemaking. The hazard index (HI: 17-108) of the average VOC concentrations suggests that health risks can be reduced by improving workplace air quality and protecting workers. PMID:20828338

Chang, E-E; Wei-Chi, Wang; Li-Xuan, Zeng; Hung-Lung, Chiang

2010-09-10

172

Ground-water levels and water-quality data for wells in the Spring Creek area near Arnold Air Force Base, Tennessee, April and May 2000  

USGS Publications Warehouse

Arnold Air Force Base (AAFB) occupies about 40,000 acres in Coffee and Franklin Counties, Tennessee. Numerous site-specific ground-water contamination investigations have been conducted at designated solid waste management units (SWMU?s) at AAFB. Several synthetic volatile organic compounds (VOC?s), primarily chlorinated solvents, have been identified in groundwater samples collected from monitoring wells near SWMU 8 in the Spring Creek area. During April and May 2000, a study of the groundwater resources in the Spring Creek area was conducted to determine if VOC?s from AAFB have affected local private water supplies and to advance understanding of the ground-water-flow system in this area. The study focused on sampling private wells located within the Spring Creek area that are used as a source of drinking water. Ground-water-flow directions were determined by measuring water levels in wells and constructing a potentiometric-surface map of the Manchester aquifer in the study area. Data were collected from a total of 35 private wells and 22 monitoring wells during the period of study. Depths to ground water were determined for 22 of the private wells and all 22 of the monitoring wells. The wells ranged in depth from 21 to 105 feet. Water-level altitudes ranged from 930 to 1,062 feet above sea level. Depths to water ranged from 8 to 83 feet below land surface. Water-quality samples were collected from 29 private wells which draw water from either gravel zones in the upper part of the Manchester aquifer, fractured bedrock in the lower part of the Manchester aquifer, or a combination of these two zones. Concentrations of 50 of the 55 VOC?s analyzed for were less than method detection limits. Chloroform, acetone, chloromethane, 2-butanone, and tetrachloroethylene were detected in concentrations exceeding the method detection limits. Only chloroform and acetone were detected in concentrations equal to or exceeding reporting limits. Chloroform was detected in a sample from one well at a concentration of 1.2 micrograms per liter (?g/L). Acetone was detected in a sample from another well at a concentration of 10 ?g/L. Acetone also was detected in a duplicate sample from the same well at an estimated concentration of 7.2 ?g/L, which is less than the reporting limit for acetone. The only contaminant of concern detected was tetrachloroethylene. Tetrachloroethylene was detected in only one sample, and this detection was at an estimated concentration below the reporting limit. None of the VOC concentrations exceeded drinking water maximum contaminant levels for public water systems.

Williams, Shannon D.; Aycock, Robert A.

2001-01-01

173

Dissolving efficacy of different organic solvents on gutta-percha and resilon root canal obturating materials at different immersion time intervals  

PubMed Central

Background Aim: The purpose of this study was to compare and evaluate the dissolving capability of various endodontic solvents used during endodontic retreatment on resilon and gutta-percha at different immersion time intervals. Materials and Methods: 160 ISO no. 40 cones (0.06 taper), 80 each of resilon and gutta-percha were taken as samples for the study. Both resilon and gutta-percha were divided into eight experimental groups of 20 cones (four groups each of resilon and gutta-percha) for immersion in xylene, tetrachloroethylene, refined orange oil and distilled water. Each group was further divided into two equal subgroups (n=10) for 2- and 5-minute immersion time intervals at room temperature to investigate the potential of these solvents for clinical use in dissolving resilon and gutta-percha. Each sample was weighed initially before immersing in the solvent on a digital analytical scale. Distilled water served as a control. Samples were removed from the respective solvents after the specified immersion period and washed in 100 ml of distilled water and allowed to dry for 24 h at 37°C in a humidifier. The samples were then again weighed after immersion in the specific solvent on a digital analytical scale. The extent of gutta-percha or resilon removed from the specimen was calculated from the difference between the original weight of gutta-percha or resilon sample and its final weight. Means and standard deviations of percentage loss of weight were calculated at each time interval for each group of specimens. The values were compared by statistical parametric tests using SPSS 16.0 Software. The data was subjected to paired ‘t‘ test, independent ‘t’ test, one-way ANOVA test and multiple comparisons with Scheffe's test. Results: There was no significance in the amount of gutta-percha dissolved at 2- and 5-minute immersion time intervals in all groups (P>0.05) except the tetrachloroethylene group (P=0.00). There was a very high significance in the amount of resilon dissolved at 2- and 5-minute immersion time intervals in all groups (P=0.00) except the xylene and distilled water (Control) groups (P>0.05). Conclusion: The results showed that xylene, refined orange oil and tetrachloroethylene can be used for softening gutta-percha/resilon during retreatment with various techniques- xylene being the best solvent both for gutta-percha and resilon.

Mushtaq, Mubashir; Farooq, Riyaz; Ibrahim, Mohammed; Khan, Fayiza Yaqoob

2012-01-01

174

Air stripping of volatile organic chlorocarbons: System development, performance, and lessons learned  

SciTech Connect

The Savannah River Site, which has been in operation since the 1950's, is a 780-square kilometer reservation that produces tritium for the national defense program. As a result of past waste handling practices, the ground water at several locations on the Site has become contaminated with solvents, metals, and radionuclides. In 1981, the ground water located under the Site's fuel and target rod fabrication area (M-Area) was found to be contaminated with degreasing solvents, specifically trichloroethylene (TCE) and tetrachloroethylene (PCE). In 1983, a program was started to evaluate air stripping and determine its applicability to cleanup of M-Area contamination. Lessons learned regarding the efficiency and effectiveness of air stripping technology are presented.

McKillip, S.T.; Sibley, K.L.; Horvath, J.G.

1991-01-01

175

Air stripping of volatile organic chlorocarbons: System development, performance, and lessons learned  

SciTech Connect

The Savannah River Site, which has been in operation since the 1950`s, is a 780-square kilometer reservation that produces tritium for the national defense program. As a result of past waste handling practices, the ground water at several locations on the Site has become contaminated with solvents, metals, and radionuclides. In 1981, the ground water located under the Site`s fuel and target rod fabrication area (M-Area) was found to be contaminated with degreasing solvents, specifically trichloroethylene (TCE) and tetrachloroethylene (PCE). In 1983, a program was started to evaluate air stripping and determine its applicability to cleanup of M-Area contamination. Lessons learned regarding the efficiency and effectiveness of air stripping technology are presented.

McKillip, S.T.; Sibley, K.L.; Horvath, J.G.

1991-12-31

176

Food chain enrichment of organochlorine compounds and mercury in clean and polluted lakes of Finland  

SciTech Connect

Lakes polluted by pulp mill and urban wastes including chlorobleaching of pulp, semipolluted lakes and reference lakes in nearly natural condition in Central Finland were studied for contents of mercury, methyl mercury and organochlorine compounds in sediment, plankton, roach and pike. Chlorobleaching has caused a 30-fold concentration of Hg in botton sediment related to that of the purest reference lake. This was not reflected to the mercury levels in fish which were highest at one natural condition (humic) lake and rather high also at semipolluted lake Paeijaenne. Mercury in fish was shown to be mostly methylated but not completely and its time trends could be estimated. Chloroform did not show, but carbon tetrachloride, tetrachloroethylene and chlorinated cymenes showed significant bioaccumulation in fish. Using fat basis attenuated the power of estimation of food chain enrichment by a three trophic level model for lipohilic biocides and a strong proof was obtained for the enrichment of hexachlorobenzene.

Paasivirta, J.; Saerkkae, J.; Surma-Aho, K.; Humppi, T.; Koukkanen, T.; Marttinen, M.

1983-01-01

177

Metallurgical Laboratory Hazardous Waste Management Facility groundwater monitoring report. First quarter 1995  

SciTech Connect

During first quarter 1995, samples from AMB groundwater monitoring wells at the Metallurgical Laboratory Hazardous Waste Management Facility (Met Lab HWMF) were analyzed for selected heavy metals, field measurements, radionuclides, volatile organic compounds, and other constituents. Six parameters exceeded standards during the quarter. As in previous quarters, tetrachloroethylene and trichloroethylene exceeded final Primary Drinking Water Standards (PDWS). Total organic halogens exceeded its Savannah River Site (SRS) Flag 2 criterion during first quarter 1995 as in fourth quarter 1994. Aluminum, iron, and manganese, which were not analyzed for during fourth quarter 1994, exceeded the Flag 2 criteria in at least two wells each during first quarter 1995. Groundwater flow direction and rate in the M-Area Aquifer Zone were similar to previous quarters. Conditions affecting the determination of groundwater flow directions and rates in the Upper Lost Lake Aquifer Zone, Lower Lost Lake Aquifer Zone, and the Middle Sand Aquifer Zone of the Crouch Branch Confining Unit were also similar to previous quarters.

NONE

1995-06-01

178

Mechanisms and controlling characteristics of the catalytic oxidation of methane  

SciTech Connect

Methane dissociation and oxygen activation have been found to be structure sensitive on different single crystal palladium surfaces. Geometrically restricted surfaces on Pd single crystal and polycrystalline surfaces using tetrachloroethylene and pentamethylcyclopentasiloxane have been formed and compared with surface structures formed using dichloromethane and chlorine. The adsorption and activation of O{sub 2}, CO, and H{sub 2}O on clean Pd surfaces and those containing the surface ensembles have also been investigated. To interpret high-resolution angle-resolved x-ray photoelectron spectra (HR AR-XPS), a new self-modeling method of resolving HR-XPS spectra was developed and applied to the experimental spectra. The effects of electron-accepting Cl, O{sub 2}, and H{sub 2}O adsobated on Cs/MoS{sub 2} were determined.

Klier, Kamil; Simmons, Gary W.; Herman, Richard G.; Park, Kenneth T.; Hess, James S.; Hunsicker, Robert A.

1999-07-01

179

Gas phase photocatalytic degradation on TiO{sub 2} pellets of volatile chlorinated organic compounds from a soil vapor extraction well  

SciTech Connect

The mineralization of trichloroethylene (TCE) and tetrachloroethylene (PCE) in gas stream from a soil vapor extraction (SVE) well was demonstrated with an annular photocatalytic reactor packed with porous TiO{sub 2} pellets in field trials at the Savannah River Site in Aiken, SC. The TiO{sub 2} pellets were prepared using a sol-gel method. The experiments were performed at 55 to 60{degree}C using space times of 10{sup 8} to 10{sup 10} g s/mol for TCE and PCE. Chloroform (CHCl{sub 3}) and carbon tetrachloride (CCl{sub 4}) were detected as minor products from side reactions. On a molar basis, CCl{sub 4} and CHCl{sub 3} produced were about 2% and 0.2 % of the reactants.

Yamazaki-Nishida, S.; Read, H.W.; Nagano, J.K.; Anderson, M.A. [Wisconsin Univ., Madison, WI (United States). Water Chemistry Program; Cervera-March, S. [Barcelona Univ., (Spain). Department of Chemical Engineering; Jarosch, T.R.; Eddy-Dilek, C.A. [Westinghouse Savannah River Co., Aiken, SC (United States)

1993-05-20

180

Organics in soils and groundwater at non-arid sites (A-1) integrated demonstration  

SciTech Connect

One of the most common environmental problems in the United States is soils and groundwater contaminated with volatile chemical solvents classified as Volatile Organic Compounds (VOCs), which were used as degreasers and cleaning agents. Leakage of solvents (trichloroethylene and tetrachloroethylene) from an underground process sewer line has contaminated soils and underlying groundwaters at SRS. This site was chosen for DOE-OTD`s integrated demonstration program to demonstrate innovative technologies for cleanup of soils and groundwater contaminated with VOCs. The Savannah River Site was especially well suited as the test bed for this integrated demonstration project due to the presence of a pre-existing line source of soil and groundwater-based contamination, on-going environmental remediation efforts at the site, and full cooperation from the concerned environmental regulatory agencies. The Integrated Demonstration (ID) at the Savannah River Site has demonstrated systems of technologies and evaluated them with respect to performance, safety and cost effectiveness.

Steele, J.L.; Kaback, D.S.; Looney, B.B.

1994-06-01

181

Health assessment for Aberdeen Proving Grounds, Aberdeen, Maryland, Region 3. CERCLIS Nos. MD3210021355 and MD10020036. Preliminary report  

SciTech Connect

The Aberdeen Proving Grounds site is located in Aberdeen (Harford County) Maryland. Preliminary on-site groundwater and surface water sampling results have identified various metals, phosphorus, and volatile organic compounds. They include: 1,2-dichloroethylene, chloroform, 1,2-dichloroethane, trichloroethylene, benzene, 1,1,2,2-tetrachloroethane, tetrachloroethylene, 1,4-dithiane and 1,2-dichloroethylene. In addition, it has been reported that among the substances disposed of on-site are significant quantities of toxic metals, cyanide compounds, phosphorus, phosgene, napalm, and mustard gas. The site is considered to be of public health concern because of the risk to human health caused by the likelihood of human exposure to hazardous substances. Potential environmental pathways include those related to contaminated groundwater, surface water, on-site soils, and volatilization of contaminants in ambient air.

Not Available

1989-01-19

182

Air pollutants formed in thermal decomposition of folpet fungicide under oxidative conditions.  

PubMed

This contribution studies the decomposition of folpet fungicide under oxidative conditions and compares the product species with those of captan fungicide, which is structurally related to folpet. Toxic products arising from folpet comprised carbon disulfide (highest emission factor of 4.9 mg g(-1) folpet), thiophosgene (14.4), phosgene (34.1), hydrogen cyanide (2.6), tetrachloroethylene (111), hexachloroethane (167), and benzonitrile (4.5). Owing to their related molecular structures, folpet emitted similar products to captan but at different yields, under the same experimental conditions. It appears that the availability of easily abstractable H atoms, in the structure of captan but not in that of folpet, defines the product distribution. In conjunction with the quantum chemical calculations, these experimental measurements afford an enhanced explanation of the formation pathways of hazardous decomposition products of these two structurally related fungicides. PMID:21121660

Chen, Kai; Mackie, John C; Kennedy, Eric M; Dlugogorski, Bogdan Z

2010-12-01

183

Health assessment for Mystery Bridge Road/US Highway 20 Site, Brookhurst Subdivision, Evansville, Natrona County, Wyoming, Region 8. CERCLIS No. WYD981546005. Preliminary report  

SciTech Connect

The Mystery Bridge Road, U.S. Highway 20 site, also known as the Brookhurst Subdivision (BSD), is located adjacent to industrial sites in Wyoming. The sites include a natural gas processing facility, an oil and gas well servicing company, and a railroad siding. Organic chemicals from the industrial sites have contaminated the underlying aquifer and resulted in contamination of downgradient drinking water wells in the BSD. The list of organic contaminants detected on-site include toluene, xylene, benzene, tetrachloroethylene (PCE), 1,1-dichloroethane, trichloroethylene (TCE), and 1,1,1-trichloroethane. An estimated 414 persons in the subdivision rely on groundwater wells for potable water. An alternative supply of potable water has been provided for these residents.

Not Available

1990-04-04

184

Competitive adsorption of VOCcs and BOM: Oxic and anoxic environments  

SciTech Connect

The effect of the presence of molecular oxygen on the adsorption of volatile organic compounds (VOCs) in distilled Milli-Q water and in water supplemented with background organic matter (BOM) is evaluated. Experiments are conducted under conditions where molecular oxygen is present in the test environment (oxic adsorption), and where oxygen is absent from the test environment (anoxic adsorption). Adsorption isotherms for tetrachloroethylene (PCE) and trichloroethylene (TCE) in Milli-Q water showed no impact of the presence of oxygen on their adsorption behavior, while adsorption isotherms for cis-1,2-dichloroethylene (DCE) showed higher capacities under toxic conditions. The Ideal Adsorbed Solution Theory (IAST) successfully predicted the VOCs anoxic adsorption isotherms in BOM. However, the IAST model did not predict the VOCs oxic adsorption isotherms in BOM.

Sorial, G.A.; Papadimas, S.P.; Suidan, M.T.; Speth, T.F.

1994-01-01

185

Transformations of 1- and 2-carbon halogenated aliphatic organic compounds under methanogenic conditions.  

PubMed Central

Several 1- and 2-carbon halogenated aliphatic organic compounds present at low concentrations (less than 100 micrograms/liter) were degraded under methanogenic conditions in batch bacterial cultures and in a continuous-flow methanogenic fixed-film laboratory-scale column. Greater than 90% degradation was observed within a 2-day detention time under continuous-flow methanogenic conditions with acetate as a primary substrate. Carbon-14 measurements indicated that chloroform, carbon tetrachloride, and 1,2-dichloroethane were almost completely oxidized to carbon dioxide, confirming removal by biooxidation. The initial step in the transformations of tetrachloroethylene and 1,1,2,2-tetrachloroethane to nonchlorinated end products appeared to be reductive dechlorination to trichloroethylene and 1,1,2-trichloroethane, respectively. Transformations of the brominated aliphatic compounds appear to be the result of both biological and chemical processes. The data suggest that transformations of halogenated aliphatic compounds can occur under methanogenic conditions in the environment.

Bouwer, E J; McCarty, P L

1983-01-01

186

Volatile chlorinated organic compound levels in rain water from Kobe City in Japan  

SciTech Connect

Water pollution by volatile chlorinated organic compounds has become a serious environmental problem. The Environmental Agency of Japan has defined the regulations on trichloroethylene, tetrachloroethylene, 1,1,1-trichloroethane and carbon tetrachloride in wastewater in 1989. In order to protect against water pollution, it is important to keep concentrations in these compounds in environmental water as low as possible. Therefore, the determination of these compounds in rain water is very important to evaluate the loading amounts of these compounds into environmental water. Since few detailed reports have been made as to the assay of these volatile substances in rain water, we investigated this and compared these compound levels in rain water collected from three different locations in Kobe, Japan. The assayed values were compared to each other. 3 refs., 4 figs., 1 tab.

Adachi, Atsuko; Kobayashi, Tadashi [Kobe Women`s College of Pharmacy (Japan)

1994-01-01

187

Mixed waste management facility groundwater monitoring report. Fourth quarter 1996 and 1996 summary  

SciTech Connect

During fourth quarter 1996, nine constituents exceeded final Primary Drinking Water Standards (PDWS) in groundwater samples from downgradient monitoring wells at the Mixed Waste Management Facility. No constituents exceeded final PDWS in samples from the upgradient monitoring wells. As in previous quarters, tritium and trichloroethylene were the most widespread elevated constituents. Carbon tetrachloride, chloroethene, chloroform, 1,1-dichloroethylene, dichloromethane, gross alpha, and tetrachloroethylene also exceeded final PDWS in one or more wells. Elevated constituents were found in numerous Aquifer Zone llB2 (Water Table) and Aquifer Zone llB1 (Barnwell/McBean) wells and in six Aquifer Unit IIA (Congaree) wells. The groundwater flow directions and rates in the three hydrostratigraphic units were similar to those of previous quarters.

NONE

1997-03-01

188

FY02 Final Report on Phytoremediation of Chlorinated Ethenes in Southern Sector Sediments of the Savannah River Site  

SciTech Connect

This final report details the operations and results of a 3-year Seepline Phytoremediation Project performed adjacent to Tims Branch, which is located in the Southern Sector of the Savannah River Site (SRS) A/M Area. Phytoremediation is a process where interactions between vegetation, associated microorganisms, and the host substrate combine to effectively degrade contaminated soils, sediments, and groundwater. Phytoremediation is a rapidly developing technology that shows promise for the effective and safe cleanup of certain hazardous wastes. It has the potential to remediate numerous volatile organic compounds (VOCs). Extensive characterization work has demonstrated that two VOCs, tetrachloroethylene (PCE) and trichloroethylene (TCE) are the major components of the VOC-contaminated groundwater that is migrating through the Southern Sector and Tims Branch seepline area (WSRC, 1999). The PCE and TCE are chlorinated ethenes (CE), and have been detected in seepline soils and ground water adjacent to the ecologically-sensitive Tims Branch seepline area.

Brigmon, R..L.

2004-01-30

189

Mixed Waste Management Facility (MWMF) groundwater monitoring report  

SciTech Connect

During first quarter 1992, tritium, trichloroethylene, tetrachloroethylene, lead, antimony, I,I-dichloroethylene, 1,2-dichloroethane, gross alpha, mercury, nickel, nitrate, nonvolatile beta, and total alpha-emitting radium (radium-224 and radium-226) exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the Mixed Waste Management Facility (MWMF) and adjacent facilities. Tritium and trichloroethylene were the most widespread constituents; 57 (49%) of the 116 monitored wells contained elevated tritium activities, and 21 (18%) wells exhibited elevated trichloroethylene concentrations Sixty-one downgradient wells screened in Aquifer Zone IIB2 (Water Table), Aquifer Zone IIB[sub 2] (Barnwell/McBean), and Aquifer Unit IIA (Congaree) contained constituents that exceeded the PDWS during first quarter 1992. Upgradient wells BGO 1D and HSB 85A, BC, and 85C did not contain any constituents that exceeded the PDWS. Upgradient well BGO 2D contained elevated tritium.

Thompson, C.Y.

1992-06-01

190

Mixed Waste Management Facility (MWMF) groundwater monitoring report. First quarter 1992  

SciTech Connect

During first quarter 1992, tritium, trichloroethylene, tetrachloroethylene, lead, antimony, I,I-dichloroethylene, 1,2-dichloroethane, gross alpha, mercury, nickel, nitrate, nonvolatile beta, and total alpha-emitting radium (radium-224 and radium-226) exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the Mixed Waste Management Facility (MWMF) and adjacent facilities. Tritium and trichloroethylene were the most widespread constituents; 57 (49%) of the 116 monitored wells contained elevated tritium activities, and 21 (18%) wells exhibited elevated trichloroethylene concentrations Sixty-one downgradient wells screened in Aquifer Zone IIB2 (Water Table), Aquifer Zone IIB{sub 2} (Barnwell/McBean), and Aquifer Unit IIA (Congaree) contained constituents that exceeded the PDWS during first quarter 1992. Upgradient wells BGO 1D and HSB 85A, BC, and 85C did not contain any constituents that exceeded the PDWS. Upgradient well BGO 2D contained elevated tritium.

Thompson, C.Y.

1992-06-01

191

Bias in biologic monitoring caused by concomitant medication  

SciTech Connect

Medication of the worker with pharmacotherapeutic agents and its meaning for individual pharmacokinetics of the agent(s) to which the worker is exposed is a largely unexplored zone, on the border of both occupational and clinical medicine. Medication and exposure to occupational agents can result in pharmacodynamic and/or pharmacokinetic interactions; the latter type of interactions will be discussed in this paper. Using styrene, toluene, tetrachloroethylene, and 1,1,1-trichloroethane as examples of solvents with various kinetic properties, it is demonstrated in what way concomitant therapy can influence the elimination of the solvent. Major emphasis is laid on the effects on conclusions drawn from biomonitoring studies in exhaled air and venous blood. To achieve this purpose, a physiologic simulation model, run on a 640-kilobyte microcomputer, is used. The simulated variation of several parameters is illustrated with examples from pharmacologic practice. 45 references.

Borm, P.J.; de Barbanson, B.

1988-03-01

192

Removal of specific organic contaminants from wastewater by activated carbon adsorption  

SciTech Connect

A two-year study, conducted for the EPA's Industrial Environmental Research Laboratory, on the use of granular activated carbon columns for the treatment of industrial wastewaters involved the removal of dioctyl phthalate from a waste stream of a plant producing mixed phthalate esters; removal of benzene, toluene, and several polynuclear aromatics from a ligh-hydrocarbon-cracking quench water; removal of ethylene dichloride, carbon tetrachloride, trichloroethylene, 1,1,2-trichloroethane, and tetrachloroethylene from a chlorinated solvent plant waste stream; and removal of ethylene dichloride and chloroform from an ethylene dichloride/vinyl chloride plant wastewater. The adsorptive characteristics of each compound with respect to the chemistry of their wastewater matrixes; the observed adsorption characteristics as predicted by modern adsorption theory; and the suitability of Total Organic Carbon as a predictor or surrogate compound to indicate the breakthrough of priority pollutants are discussed.

Beaude, B.A.; Bilello, L.J.; Turner, R.J.; Kellar, E.M.

1980-01-01

193

Thermal degradation of 2-chlorophenol promoted by CuCl2 or CuCl: formation and destruction of PCDD/Fs.  

PubMed

The oxidative degradation of 2-chlorophenol in air (equivalence ratio phi=0.8) was investigated at 350 degrees C by using the sealed tube technique under different conditions: in the gas phase and in the presence of copper chlorides (CuCl2 and CuCl in different proportions). Not only PCDD/Fs but carbon oxides and other organic products such as chlorophenols, chlorobenzenes, tetrachloroethylene and tetrachlorocyclopentenedione were quantified in order to evaluate the relative importance of reaction pathways. Additional experiments were performed to analyse the degradation products of octachlorodibenzodioxin and 2-monochlorodibenzodioxin. Although it was stated that chlorobenzenes could be formation precursors for PCDD/Fs, experimental data obtained in this work show that chlorobenzenes can also be degradation products of PCDD/Fs. PMID:17223176

Visez, Nicolas; Sawerysyn, Jean-Pierre

2007-01-16

194

Current Intelligence Bulletins: summaries, September 1987  

SciTech Connect

Brief summaries of 49 NIOSH Current Intelligence Bulletins were provided in a cumulative listing. Permissible Exposure Limits were included where applicable, and notes were provided with some summaries indicating further action or data since original publication. Topics covered include chloroprene, trichloroethylene, ethylene-dibromide, chrome pigment, asbestos, hexamethylphosphoric-triamide, polychlorinated-biphenyls, 4,4'-diaminodiphenylmethane, chloroform, radon daughters, dimethylcarbamoyl-chloride, diethylcarbamoyl-chloride, explosive azide hazard, arsenic, nitrosamines, metabolic precursors of beta-naphthylamine, 2-nitropropane, acrylonitrile, 2,4-diaminoanisole, tetrachloroethylene, trimellitic-anhydride, ethylene-thiourea, ethylene-dibromide, disulfiram, dyes, ethylene-dichloride, chloroethanes, vinyl halides, glycidyl ethers, epichlorohydrin, smoking, arsine, radiofrequency sealers, formaldehyde, ethylene-oxide, silica flour, vibration syndrome, glycol ethers, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 1,3-butadiene, cadmium, monohalomethanes, dinitrotoluenes, methylene-chloride, 4,4'-methylenedianiline, organic solvents, and injuries and amputations from working with power presses.

Not Available

1987-09-01

195

NIOSH current intelligence bulletins: summaries  

SciTech Connect

Summaries were offered of the current intelligence bulletins issued from January 20, 1975 to August of 1988. They include information on the following topics: chloroprene, trichloroethylene, ethylene dibromide, chrome pigment, asbestos, hexamethylphosphoric triamide, polychlorinated biphenyls, 4,4'-diaminodiphenylmethane, chloroform, radon daughters, dimethylcarbamoyl chloride, diethylcarbamoyl-chloride, explosive azide hazard, inorganic arsenic, nitrosamines in cutting fluids, metabolic precursors of beta-naphthylamine, 2-nitropropane, acrylonitrile, 2,4-diaminoanisole, tetrachloroethylene, trimellitic anhydride, ethylene thiourea, disulfiram, direct-blue-6, direct-black-38, direct-brown-95, benzidine derived dyes, ethylene dichloride, NIAX catalyst ESN, chloroethanes, vinyl halides, glycidyl ethers, epichlorohydrin, smoking, arsine poisoning, radiofrequency sealers and heaters, formaldehyde, ethylene oxide, silica flour, vibration syndrome, glycol ethers, 2,3,7,8-tetrachlorodibenzo-p-dioxin, 1,3-butadiene, cadmium, monohalomethanes, dinitrotoluenes, methylene chloride, 4,4'-methylenedianiline, organic solvent neurotoxicity, mechanical power press injuries, and the carcinogenic effects of diesel exhaust.

Not Available

1988-09-01

196

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

SciTech Connect

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.

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

2004-03-31

197

Solvent release into a sandy aquifer 3: enhanced dissolution by methanol injection.  

PubMed

A field experiment involving a release of 5 litres of a mixture of chlorinated solvents (0.5 l of chloroform, 2.0 l of trichloroethylene, and 2.5 l of tetrachloroethylene) was carried out in a sandy, unconfined, shallow aquifer at Canadian Forces Base Borden, east of Toronto, Ontario, Canada. The dissolution of the chlorinated solvents into the groundwater was studied in detail for 220 days, then a methanol/water mixture was injected to study the possible enhancement of the dissolution. An effect of the methanol injection was only observed at a few sampling points, likely due to the distribution of the solvent as a laterally extensive, thin pool. This investigation shows that it is crucial to know the exact location of the dense nonaqueous phase liquids (DNAPL) in the subsurface when designing and performing remedial techniques at contaminated sites. PMID:17283944

Broholm, K

2007-01-01

198

The temperature dependence of the emission of perchloroethylene from dry cleaned fabrics.  

PubMed

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 degrees C. A linear relation exists between the logarithm of perchloroethylene retention time (tau) and the reciprocal of the absolute temperature (1/T). The temperature dependence of the retention time can be expressed as tau = 2.36 x 10(-16)e13,892/T and 8.38 x 10(-9)e8766/T sec for 100% wool and 55% polyester/45% wool fabrics, respectively. These results indicate that "airing out" freshly dry cleaned fabrics at temperatures near 20 degrees C for short time periods (e.g., 5 hr) will not appreciably reduce the total emissions of perchloroethylene. PMID:2351125

Guo, Z S; Tichenor, B A; Mason, M A; Plunket, C M

1990-06-01

199

Health assessment for American Lake Gardens, Tacoma, Pierce County, Washington, Region 10. CERCLIS No. WAD980833065. Preliminary report  

SciTech Connect

The American Lake Gardens site is on the National Priorities List. Two areas within the site are the areas of primary contamination; the northeast section's contamination is believed to have come from the closed landfill (now a golf course) on McChord AFB, and the southwest section's contamination from Fort Lewis. Both Fort Lewis and McChord AFB are NPL sites. The environmental contamination on-site consists of trans-1,2-dichloroethylene (530 ppb), trichloroethylene (260 ppb), methylene chloride (38 ppb), tetrachloroethylene (52 ppb), benzene (6 ppb), and 1,1,1-trichloroethane (18 ppb) in ground water. The site is considered to be of potential public health concern because of the risk to human health caused by the possibility of exposure to hazardous substances via ground water (from private wells still in use) and surface water.

Not Available

1989-01-19

200

Comparison of temporal trends in VOCs as measured with PDB samplers and low-flow sampling methods  

USGS Publications Warehouse

Analysis of temporal trends in tetrachloroethylene (PCE) concentration determined by two sample techniques showed that passive diffusion bag (pdb) samplers adequately sample the large variation in PCE concentrations at the site. The slopes of the temporal trends in concentrations were comparable between the two techniques, and the pdb sample concentration generally reflected the instantaneous concentration sampled by the low-flow technique. Thus, the pdb samplers provided an appropriate sampling technique for PCE at these wells. One or two wells did not make the case for widespread application of pdb samples at all sites. However, application of pdb samples in some circumstances was appropriate for evaluating temporal and spatial variations in VOC concentrations, thus, should be considered as a useful tool in hydrogeology.

Harte, P. T.

2002-01-01

201

Health assessment for Vega Alta Public Supply Wells Site, Vega Alta, Puerto Rico, Region 2. CERCLIS No. PRS187147. Final report  

SciTech Connect

The Vega Alta Public Supply Wells Site is a public water supply wellfield located in the municipality of Vega Alta, Puerto Rico. Based on data collected from 1983 to 1985, the ground water is contaminated with volatile organic chemicals (VOCs), notably trichloroethylene, tetrachloroethylene, and 1,2-trans-dichloroethylene. A remediation alternative selected in a Record of Decision dated September 29, 1987 calls for treatment of 4 of the more highly contaminated wells and shutting down 2 others. Remediation efforts are to include air stripping and possibly treatment by carbon adsorption. Monitoring of the effectiveness of these efforts will determined their adequacy to bring the quality of the tap water to acceptable levels. It is not known whether the water currently supplied through the municipality has elevated concentrations of VOCs. Therefore, based on the limited information available, ATSDR has concluded that the Vega Alta Wells site is of public health concern.

Not Available

1988-12-02

202

Mixed Waste Management Facility groundwater monitoring report, First quarter 1994  

SciTech Connect

During first quarter 1994, nine constituents exceeded final Primary Drinking Water Standards in groundwater samples from downgradient monitoring wells at the Mixed Waste Management Facility, the Old Burial Ground, the E-Area Vaults, the proposed Hazardous Waste/Mixed Waste Disposal Vaults, and the F-Area Sewage Sludge Application Site. As in previous quarters, tritium and trichloroethylene were the most widespread elevated constituents. Chloroethene (vinyl chloride), copper, 1,1-dichloroethylene, lead, mercury, nonvolatile beta, or tetrachloroethylene also exceeded standards in one or more wells. Elevated constituents were found in numerous Aquifer Zone IIB{sub 2} (Water Table) and Aquifer Zone IIB{sub 1}, (Barnwell/McBean) wells and in one Aquifer Unit IIA (Congaree) well. The groundwater flow directions and rates in the three hydrostratigraphic units were similar to those of previous quarters.

Not Available

1994-06-01

203

Method for detecting toxic gases  

DOEpatents

A method capable of detecting low concentrations of a pollutant or other component in air or other gas, utilizing a combination of a heating filament having a catalytic surface of a noble metal for exposure to the gas and producing a derivative chemical product from the component, and an electrochemical sensor responsive to the derivative chemical product for providing a signal indicative of the product. At concentrations in the order of about 1-100 ppm of tetrachloroethylene, neither the heating filament nor the electrochemical sensor is individually capable of sensing the pollutant. In the combination, the heating filament converts the benzyl chloride to one or more derivative chemical products which may be detected by the electrochemical sensor.

Stetter, Joseph R. (Naperville, IL); Zaromb, Solomon (Hinsdale, IL); Findlay, Jr., Melvin W. (Bolingbrook, IL)

1991-01-01

204

Health assessment for National Presto Industries, Eau Claire, Wisconsin, Region 5. CERCLIS No. WID006196174. Preliminary report  

SciTech Connect

The National Presto Industries, Inc. facility at Eau Claire, Wisconsin included facilities for powder storage and mixing, chemical storage and mixing, and primer manufacture and storage. Major contaminants on-site include VOCs, polychlorinated biphenyls (PCBs), and heavy metals. The highest concentrations of heavy metals are in lagoon water, spent forging compound, and waste drums from the East Disposal Area. Four chemicals, all of which are carcinogenic in laboratory animals, were measured in concentrations exceeding Wisconsin ground water enforcement standards: 1,2-dichloroethane, 1,1-dichloroethylene, tetrachloroethylene, and trichloroethylene. The presence of VOCs in residential wells in the area adjacent to the site is a public health concern. Previous studies indicate that VOCs in residential well water of forty residences near the site exceed Wisconsin ground water enforcement standards.

Not Available

1988-11-09

205

Mixed waste management facility groundwater monitoring report. Fourth quarter 1995 and 1995 summary  

SciTech Connect

During fourth quarter 1995, seven constituents exceeded final Primary Drinking Water Standards (PDWS) in groundwater samples from downgradient monitoring wells at the Mixed Waste Management Facility. No constituents exceeded final PDWS in samples from the upgradient monitoring wells. As in previous quarters, tritium and trichloroethylene were the most widespread elevated constituents. Chloroethene, gross alpha, lead, mercury, and tetrachloroethylene also exceeded final PDWS in one or more wells. Elevated constituents were found in numerous Aquifer Zone IIB{sub 2} (Water Table) and Aquifer Zone IIB{sub 1} (Barnwell/McBean) wells and in three Aquifer Unit IIA (Congaree) wells. The groundwater flow directions and rates in the three hydrostratigraphic units were similar to those of previous quarters.

NONE

1996-03-01

206

Electrochemical Processes for In-situ Treatment of Contaminated Soils  

SciTech Connect

Soils at typical DOE (Department of Energy) waste sites are known to be contaminated by a host of hazardous organic chemicals, heavy metals and radionuclides. Typical hazardous organic contaminants include chlorinated solvents such as trichloroethylene (TCE), tetrachloroethylene (PCE), chloroform, and carbon tetrachloride, and polycyclic aromatic hydrocarbons (PAHs) such as naphthalene, fluorene, phenanthrene, anthracene and pyrene. It is also known that major toxic heavy metals such as Pb, Cr, As, Zn, Cu, Hg, and Cd and major radionuclides such as Tritium, U, Sr90, Pu, Cs137, and Tc are also commonly present at some DOE waste sites. Some of these chemicals are relatively mobile and can migrate down to the vadose zone and/or the aquifer region.

Huang, C.P.; Cha, Daniel

1999-06-01

207

Bioremediation of contaminated groundwater  

DOEpatents

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

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

1994-01-01

208

Sanitary Landfill Groundwater Monitoring Report. Fourth Quarter 1997 and 1997 Summary  

SciTech Connect

A maximum of forty-eight wells of the LFW series monitor groundwater quality in the Steed Pond Aquifer (Water Table) beneath the Sanitary Landfill at the Savannah River Site (SRS). These wells are sampled quarterly to comply with the South Carolina Department of Health and Environmental Control Domestic Water Permit DWP-087A and as part of the SRS Groundwater Monitoring Program. Chloroethene (vinyl chloride) and trichloroethylene were the most widespread constituents exceeding standards during 1997. Lead (total recoverable), 1,4-dichlorobenzene, mercury, benzene, dichloromethane (methylene chloride), a common laboratory contaminant, tetrachloroethylene, 1,2-dichloroethane, gross alpha, tritium, and 1.2-dichloropropane also exceeded standards in one or more wells. The groundwater flow direction in the Steed Pond Aquifer (Water Table) beneath the Sanitary Landfill was to the southeast (universal transverse Mercator coordinates). The flow rate in this unit was approximately 139 ft/year during first quarter 1997 and 132 ft/year during fourth quarter.

Chase, J. [Westinghouse Savannah River Company, AIKEN, SC (United States)

1998-02-01

209

Sanitary Landfill groundwater monitoring report. Fourth quarterly report and summary 1993  

SciTech Connect

Fifty-seven wells of the LFW series monitor groundwater quality in Steed Pond Aquifer (Water Table) beneath the Sanitary Landfill at the Savannah River Site (SRS). These wells are sampled quarterly to comply with the South Carolina Department of Health and Environmental Control Domestic Waste Permit DWP-087A and as part of the SRS Groundwater Monitoring Program. Dichloromethane a common laboratory contaminant, and trichloroethylene were the most widespread constituents exceeding standards during 1993. Benzene, chlorobenzene, chloroethene 1,2 dichloroethane, 1,1-dichloroethylene, 1,2-dichloropropane, gross alpha, lindane, mercury, tetrachloroethylene, and tritium also exceeded standards in one or more wells. No groundwater contaminants were observed in wells screened in the lower section of Steed Pond Aquifer.

Not Available

1994-02-01

210

P-Area Reactor 1993 annual groundwater monitoring report  

SciTech Connect

Groundwater was sampled and analyzed during 1993 from wells monitoring the water table at the following locations in P Area: well P 24A in the eastern section of P Area, the P-Area Acid/Caustic Basin, the P-Area Coal Pile Runoff Containment Basin, the P-Area Disassembly Basin, the P-Area Burning/Rubble Pit, and the P-Area Seepage Basins. During 1993, pH was above its alkaline standard in well P 24A. Specific conductance was above its standard in one well each from the PAC and PCB series. Lead exceeded its 50 {mu}g/L standard in one well of the PDB series during one quarter. Tetrachloroethylene and trichloroethylene were detected above their final primary drinking water standards in one well of the PRP well series. Tritium was consistently above its DWS in the PDB and PSB series. Also during 1993, radium-228 exceeded the DWS for total radium in three wells of the PAC series and one well of the PCB series; total alpha-emitting radium exceeded the same standard in a different PCB well. These results are fairly consistent with those from previous years. Unlike results from past years, however, no halogenated volatiles other than trichloroethylene and tetrachloroethylene exceeded DWS in the PRP well series although gas chromatographic volatile organic analyses were performed throughout the year. Some of the regulated units in P Area appear to need additional monitoring by new wells because there are insufficient downgradient wells, sometimes because the original well network, installed prior to regulation, included sidegradient rather than downgradient wells. No monitoring wells had been installed through 1993 at one of the RCRA/CERCLA units named in the Federal Facilities Agreement, the Bingham Pump Outage Pits.

NONE

1994-11-01

211

Historical review on development of environmental quality standards and guideline values for air pollutants in Japan.  

PubMed

Environmental quality standards (EQSs) have been established as desirable levels to be maintained for protection of human health and the conservation of the living environment by Basic Environment Law. EQSs in ambient air had been set for 10 substances (sulfur dioxide (SO(2)), carbon monoxide (CO), suspended particulate matter (SPM), nitrogen dioxide (NO(2)) and photochemical oxidants (Ox), benzene, tetrachloroethylene, trichloroethylene, dioxins and dichloromethane) and guideline values for 7 (acrylonitorile, vinyl chloride monomer, mercury, nickel compounds, 1,3-butadiene, chloroform and 1,2-dichloromethane) in Japan by 2009. EQSs for the classical (or traditional) air pollutants, SO(2), CO, SPM, NO(2) and Ox, were set according to the minimal requirement to protect human health, based on evidence from epidemiological studies conducted before the 1970s. In 1996, the Central Environment Council designated substances which may be hazardous air pollutants and substances requiring priority action, and adopted the concept of risk assessment to set EQSs and guideline values. A life-long risk level (virtually safe dose) of 10(-5) was used to set EQS for benzene, and guideline values for vinyl chloride monomer, nickel compounds, and 1,3-butadiene. EQSs for trichloroethylene, tetrachloroethylene and dichloromethane, and guideline values for acrylonitorile and mercury were set using uncertain factors and lowest observed adverse effect (LOAEL)/no observed adverse effect level (NOAEL). The results of animal experiments were utilized to set guideline values for chloroform and 1,2-dichloroethane. The benchmark approach and human equivalent concentration (HEC) were adopted for 1,2-dichloroethane. The history of setting EQSs and guideline values for hazardous air pollutants is one of adopting new concepts into risk assessment. PMID:21680244

Kawamoto, Toshihiro; Pham, Thi-Thu-Phuong; Matsuda, Takayuki; Oyama, Tsunehiro; Tanaka, Masayuki; Yu, Hsu-Sheng; Uchiyama, Iwao

2011-06-15

212

The use of Markov chain Monte Carlo uncertainty analysis to support a Public Health Goal for perchloroethylene.  

PubMed

The current Public Health Goal (PHG) for perchloroethylene (PCE) was derived using upper-bound estimates of fractional PCE metabolism in humans. These estimates were in part obtained from a published evaluation of the uncertainty and variability in human PCE metabolism conducted using a physiologically-based pharmacokinetic (PBPK) model in a Markov chain Monte Carlo (MCMC) analysis; however, the data used in that analysis were limited to post-exposure PCE blood and exhaled air concentrations from a single study. A more recent study [Volkel, W., Friedewald, M., Lederer, E., Pahler, A., Parker, J., Dekant, W., 1998. Biotransformation of perchloroethene: dose-dependent excretion of trichloroacetic acid, dichloroacetic acid, and N-acetyl-S-(trichlorovinyl)-l-cysteine in rats and humans after inhalation. Toxicol. Appl. Pharmacol. 153(1), 20-27.] provides data on blood concentrations of PCE and its major metabolite, trichloroacetic acid (TCA), and urinary excretion of TCA following exposure of human subjects to lower concentrations of PCE (10-40ppm) than in previous studies. In the present effort, a new MCMC analysis was performed that focused on data from this study along with two others [Fernandez, J., Guberan, E., Caperos, J., 1976. Experimental human exposures to tetrachloroethylene vapor and elimination in breath after inhalation. Am. Ind. Hyg. Assoc. J. 37, 143-150; Monster, A., Boersma, G., Steenweg, H., 1979. Kinetics of tetrachloroethylene in volunteers; influence of exposure concentration and work load. Int. Arch. Occup. Environ. Health 42, 303-309.] providing data on PCE blood concentrations and urinary excretion of TCA. To provide an accurate prediction of TCA kinetics, the PBPK model used here includes a description of the metabolism of PCE to TCA in both the liver and kidney. The resulting upper 95th percentile estimates of fraction of PCE metabolized by inhalation and oral routes were 2.1 and 5.2%, respectively, compared to 58 and 79% used in the derivation of the PHG. PMID:16901594

Covington, Tammie R; Robinan Gentry, P; Van Landingham, Cynthia B; Andersen, Melvin E; Kester, Janet E; Clewell, Harvey J

2006-08-09

213

Physiological characterization of a broad spectrum reductively dechlorinating consortium  

USGS Publications Warehouse

A wetland sediment-derived microbial consortium (WBC-2) was developed by the US Geological Survey and propagated in vitro to large quantities by SiREM Laboratory for potential use in bioaugmentation applications. On the basis of bench-scale tests, the consortium could completely dechlorinate 1,1,2,2-tetrachloroethylene, tetrachloroethylene, trichloroethylene, 1,1,2-trichloroethane, cis- and trans-1,2-dichoroethylene, 1,1-dichloroethylene, 1,2-dichloroethane, and vinyl chloride in culture medium. Batch microcosms were carried out under anaerobic conditions in culture medium with neutral pH and with pH adjusted from acidic (pH 4, 5, and 6) to alkaline (pH 8 and 9). To evaluate oxygen sensitivity of WBC-2, an aliquot was removed from an anaerobic culture vessel and poured into smaller containers on the bench top where a series of oxygen exposures were applied to the culture by bubbling ambient air through the culture at a rate of ??? 100 mL/min. Chlorinated methanes tended to inhibit activity of a wide range of microorganisms. Although toxicity effects from CT addition were observed with WBC-2 in liquid culture at 3 mg/L concentration, WBC-2 in the columns could maintain degradation of CT and chloroform (CF) and of the chlorinated ethanes and ethylenes at CT and CF concentrations of 10 and 20 mg/L, respectively. This is an abstract of a paper presented at the Proceedings of the 8th International In Situ and On-Site Bioremediation Symposium (Baltimore, MD 6/6-9/2005).

Lorah, M. M.; Majcher, E.; Jones, E.; Driedger, G.; Dworatzek, S.; Graves, D.

2005-01-01

214

Surfactant Behavior and Application with a Brine-Based Remediation Technology  

NASA Astrophysics Data System (ADS)

With the general inability of existing groundwater remediation techniques to efficiently remove dense nonaqueous phase liquids (DNAPLs) from the subsurface, a novel strategy known as the Brine-Based Remediation Technology (BBRT), which relies upon a brine barrier to control downward migration of DNAPL after exposure to an interfacial tension reducing surfactant, has been proposed as a potential alternative to currently used remedial strategies. The choice of surfactants is a challenging problem and much effort has been devoted to screening of surfactants for DNAPL systems. However, due to the sensitivity of many of these surfactant solutions to electrolyte concentrations, they are unsuitable for BBRTs due to the presence of a high concentration brine. Therefore, it is necessary to characterize and evaluate potential surfactant formulations that possess favorable phase behavior, do not precipitate in the presence of high concentration brines, perform favorably in subsurface systems, (i.e., low viscosities and limited losses due to sorption), and effectively reduce interfacial tension to levels required for mobilization. Batch reactor studies were performed that identified surfactant formulations that did not precipitate in solutions containing high concentrations of calcium bromide brine and that possessed favorable phase behavior. The best behaved formulations contained a mixture of a nonionic surfactant, Triton X-100, and an anionic surfactant, Aerosol MA-80. Sorption of one of these mixtures was evaluated in experiments conducted in batch and one-dimensional column reactors. The ability of the mixture to mobilize tetrachloroethylene was evaluated in column experiments. The mixture was used in a BBRT demonstration at the Dover National Test Site in Dover, DE, where a test cell was contaminated with tetrachloroethylene.

Pedit, J. A.; Sanderson, P. M.; Johnson, D. N.; Miller, C. T.

2006-12-01

215

Simultaneous indoor and outdoor on-line hourly monitoring of atmospheric volatile organic compounds in an urban building. The role of inside and outside sources.  

PubMed

Indoor air quality (IAQ) has become a very important issue in recent years. As in developed countries people spend more than 90% of their time indoors, besides outdoor pollution assessment, the indoor one is also required. IAQ is not only affected by indoor sources linked to indoor activities, outdoor sources such as road or street traffic and industrial and commercial activities have their role too. Volatile organic compounds (VOCs) frequently show higher indoor mixing ratios with respect to the outdoor ones, and monitoring is required to report their indoor mixing ratios. Many studies have reported average indoor VOCs' mixing ratios in different environments, but their temporal variability has not been well documented. The main objective of this work was to simultaneously measure VOCs' indoor and outdoor mixing ratios with high time-resolution in order to assess the effect of sources inside and outside the building upon indoor mixing ratios of individual VOCs. Simultaneous hourly, continuous, and on-line measurements of C(2)-C(11) VOCs were performed inside and outside the School of Engineering of Bilbao (ETSI) building, located in the city center of Bilbao, an urban area in Northern Spain. The analysis of simultaneous data allowed the classification of VOCs based on their main sources. Some VOCs were mainly emitted by indoor sources (1-pentene, 2-methylpentane, n-hexane, methylcyclopentane, benzene, 1-heptene+2,2,4-trimethylbenzene, and tetrachloroethylene) or by outdoor sources (n-heptane, C(8) alkanes except trimethylpentanes and C(9) aromatics). Other VOCs, such as toluene, were emitted by both indoor and outdoor sources. The isoprene indoor pattern indicated that its main indoor source could be the air exhaled by people occupying the building. Some halocarbons, such as trichloroethylene, tetrachloroethylene, and carbon tetrachloride may be generated from the use inside the building of chlorine bleach containing products. PMID:22542255

de Blas, Maite; Navazo, Marino; Alonso, Lucio; Durana, Nieves; Gomez, Maria Carmen; Iza, Jon

2012-04-26

216

Evaluation of the atmosphere as a source of volatile organic compounds in shallow groundwater  

USGS Publications Warehouse

The atmosphere as a source of volatile organic compounds (VOCs) in shallow groundwater was evaluated over an area in southern New Jersey. Chloroform, methyl tertbutyl ether (MTBE), 1,1,1-trichloroethane, tetrachloroethylene (PCE), and carbon disulfide (not a VOC) were detected frequently at low-level concentrations in a network of 78 shallow wells in the surficial Kirkwood-Cohansey aquifer system. The atmosphere was sampled for these compounds and only MTBE concentrations were high enough to potentially explain frequent detection in shallow groundwater. A mathematical model of reactive transport through the unsaturated zone is presented to explain how variations in unsaturated properties across the study area could explain differences in MTBE concentrations in shallow groundwater given the atmosphere as the source. Even when concentrations of VOCs in groundwater are low compared to regulatory concentration limits, it is critical to know the source. If the VOCs originate from a point source(s), concentrations in groundwater could potentially increase over time to levels of concern as groundwater plumes evolve, whereas if the atmosphere is the source, then groundwater concentrations would be expected to remain at low-level concentrations not exceeding those in equilibrium with atmospheric concentrations. This is the first analysis of VOC occurrence in shallow groundwater involving colocated atmosphere data.The atmosphere as a source of volatile organic compounds (VOCs) in shallow groundwater was evaluated over an area in southern New Jersey. Chloroform, methyl tert-butyl ether (MTBE), 1,1,1-trichloroethane, tetrachloroethylene (PCE), and carbon disulfide (not a VOC) were detected frequently at low-level concentrations in a network of 78 shallow wells in the surficial Kirkwood-Cohansey aquifer system. The atmosphere was sampled for these compounds and only MTBE concentrations were high enough to potentially explain frequent detection in shallow groundwater. A mathematical model of reactive transport through the unsaturated zone is presented to explain how variations in unsaturated properties across the study area could explain differences in MTBE concentrations in shallow groundwater given the atmosphere as the source. Even when concentrations of VOCs in groundwater are low compared to regulatory concentration limits, it is critical to know the source. If the VOCs originate from a point source(s), concentrations in groundwater could potentially increase over time to levels of concern as groundwater plumes evolve, whereas if the atmosphere is the source, then groundwater concentrations would be expected to remain at low-level concentrations not exceeding those in equilibrium with atmospheric concentrations. This is the first analysis of VOC occurrence in shallow groundwater involving collocated atmosphere data.

Baehr, A. L.; Stackelberg, P. E.

1999-01-01

217

Mixed Waste Management Facility groundwater monitoring report: Third quarter 1994  

SciTech Connect

Currently, 125 wells monitor groundwater quality in the uppermost aquifer beneath the Mixed Waste Management Facility (MWMF) at the Savannah River Site. Samples from the wells are analyzed for selected heavy metals, herbicides/pesticides, indicator parameters, radionuclides, volatile organic compounds, and other constituents. As in previous quarters, tritium and trichloroethylene were the most widespread elevated constituents during third quarter 1994. Sixty-four (51%) of the 125 monitoring wells contained elevated tritium activities. Trichloroethylene concentrations exceeded the final PDWS in 22 (18%) wells. Chloroethene, 1,1-dichloroethylene, and tetrachloroethylene, elevated in one or more wells during third quarter 1994, also occurred in elevated levels during second quarter 1994. These constituents generally were elevated in the same wells during both quarters. Gross alpha, which was elevated in only one well during second quarter 1994, was elevated again during third quarter. Mercury, which was elevated during first quarter 1994, was elevated again in one well. Dichloromethane was elevated in two wells for the first time in several quarters.

Not Available

1994-12-01

218

Health assessment for Wells G and H Site, Woburn, Massachusetts, Region 1. CERCLIS No. MAD980732168. Final report  

SciTech Connect

The National Priority List (NPL) site, Wells G and H, were used from 1964 to 1979 to supplement Woburn drinking water supplies. The ground water extracted from Wells G and H was found to be contaminated with volatile organic compounds in 1979. The predominant ground water contaminants are trichloroethylene, tetrachloroethylene, trans-1,2-dichloroethylene and 1,1,1-trichloroethane. Ground water and both surface and subsurface soil contamination on-site is extensive and results from: liquid-waste spills on the ground, sludge disposal, buried and surface disposal of 55-gallon drums, and leaking tanks. A potential exists for human exposure to contaminants by: (1) inhalation of fugitive dusts and vapors from surface soils, industrial use of contaminated well water, and migration of vapors from contaminated shallow ground water to the inside of buildings; (2) dermal contact with contaminated surface soils and contaminated industrial well water; and (3) ingestion of fugitive dusts, surface soils, and, possibly, contaminated fish and contaminated industrial well water. Contaminated sediments also pose a potential exposure source should direct contact occur. The site is of public health concern.

Not Available

1989-04-25

219

Stress survival of a genetically engineered Pseudomonas in soil slurries: Cytochrome P-450cam-catalyzed dehalogenation of chlorinated hydrocarbons  

SciTech Connect

Biological treatment of hazardous chemical wastes has potential as an effective, practical, and economically viable process in above the ground treatment systems that consist of both genetically engineered microorganisms (GEMs) and bioreactors with process control instruments to create ideal conditions for biodegradation. A strain of Pseudomonas putida coexpressing cytochrome P-450cam and luciferase (lux) that provides both the reductive detoxification potential of the hemoprotein and a mechanism for its reduction to survive and remain metabolically competent under nutrient stress in soil slurry microcosms. More than 74% of the cells of engineered Pseudomonas were culturable after 7 days of multiple nutrient (C,N,P) starvation. The diagnostic luminescence and carbon monoxide-difference spectra for the two engineered traits could be detected in a significant fraction of the surviving population. The GEM could be revived after repeated desiccation and starvation using Luria broth, benzoate, or citrate as nutrients. Soil slurries inoculated with the GEM transformed hexachloroethane (HCE) to tetrachloroethylene (tetraCE) 8--10 fold faster than uninoculated slurries. The GEM also transformed the insecticide, {gamma}-HCH ({gamma}-3,4,5,6-hexachlorocyclhexene), to {gamma}-3,4,5,6-tetrachlorocyclohexene ({gamma}tetraCH) in soil slurries under subatmospheric conditions. These results indicate that GEMs can be constructed with broad substrate range detoxification catalysts such as cytochrome P-450 for remediation.

Rattan, K.; Shanker, R.; Khanna, P.; Atkins, W.M.

1999-10-01

220

Simulation of solute transport across low-permeability barrier walls.  

PubMed

Low-permeability, non-reactive barrier walls are often used to contain contaminants in an aquifer. Rates of solute transport through such barriers are typically many orders of magnitude slower than rates through the aquifer. Nevertheless, the success of remedial actions may be sensitive to these low rates of transport. Two numerical simulation methods for representing low-permeability barriers in a finite-difference groundwater-flow and transport model were tested. In the first method, the hydraulic properties of the barrier were represented directly on grid cells and in the second method, the intercell hydraulic-conductance values were adjusted to approximate the reduction in horizontal flow, allowing use of a coarser and computationally efficient grid. The alternative methods were tested and evaluated on the basis of hypothetical test problems and a field case involving tetrachloroethylene (PCE) contamination at a Superfund site in New Hampshire. For all cases, advective transport across the barrier was negligible, but preexisting numerical approaches to calculate dispersion yielded dispersive fluxes that were greater than expected. A transport model (MODFLOW-GWT) was modified to (1) allow different dispersive and diffusive properties to be assigned to the barrier than the adjacent aquifer and (2) more accurately calculate dispersion from concentration gradients and solute fluxes near barriers. The new approach yields reasonable and accurate concentrations for the test cases. PMID:16600421

Harte, Philip T; Konikow, Leonard F; Hornberger, George Z

2006-04-05

221

Test plan for single well injection/extraction characterization of DNAPL  

SciTech Connect

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.

Looney, B.B.; Jerome, K.M.; Burdick, S.; Rossabi, J.; Jarosch, T.R.; Eddy-Dilek, C.A.

1995-12-01

222

Cytogenetic analysis of an exposed-referent study: perchloroethylene-exposed dry cleaners compared to unexposed laundry workers  

PubMed Central

Background Significant numbers of people are exposed to tetrachloroethylene (perchloroethylene, PCE) every year, including workers in the dry cleaning industry. Adverse health effects have been associated with PCE exposure. However, investigations of possible cumulative cytogenetic damage resulting from PCE exposure are lacking. Methods Eighteen dry cleaning workers and 18 laundry workers (unexposed controls) provided a peripheral blood sample for cytogenetic analysis by whole chromosome painting. Pre-shift exhaled air on these same participants was collected and analyzed for PCE levels. The laundry workers were matched to the dry cleaners on race, age, and smoking status. The relationships between levels of cytological damage and exposures (including PCE levels in the shop and in workers' blood, packyears, cumulative alcohol consumption, and age) were compared with correlation coefficients and t-tests. Multiple linear regressions considered blood PCE, packyears, alcohol, and age. Results There were no significant differences between the PCE-exposed dry cleaners and the laundry workers for chromosome translocation frequencies, but PCE levels were significantly correlated with percentage of cells with acentric fragments (R2 = 0.488, p < 0.026). Conclusions There does not appear to be a strong effect in these dry cleaning workers of PCE exposure on persistent chromosome damage as measured by translocations. However, the correlation between frequencies of acentric fragments and PCE exposure level suggests that recent exposures to PCE may induce transient genetic damage. More heavily exposed participants and a larger sample size will be needed to determine whether PCE exposure induces significant levels of persistent chromosome damage.

2011-01-01

223

Relation of organic contaminant equilibrium sorption and kinetic uptake in plants.  

PubMed

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 orthe 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. PMID:16053085

Li, Hui; Sheng, Guangyao; Chiou, Cary T; Xu, Ouyong

2005-07-01

224

Distribution of volatile organic compounds in Sicilian groundwaters analysed by head space-solid phase micro extraction coupled with gas chromatography mass spectrometry (SPME/GC/MS).  

PubMed

This work presents the results of an assessment of the existence and concentration of 13 volatile organic compounds (VOCs) in groundwaters from 14 hydrological basins in Sicily (25,710km (2)). On the basis of hydrological, hydrogeochemical and geological studies, 324 sampling points were selected. All groundwater sampled were collected twice, from October to December 2004 and from February to May 2005, and were analysed to determine the concentration and spatial distribution of the VOCs in the aquifers. The need to analyze a large number of samples in a short space of time so as to obtain quantitative analyses in trace concentration levels spurred us to create a new analytical method, both simple and sensitive, based on HS-SPME/GC/MS. The concentrations of VOCs measured in industrial and intensive agricultural unconfined aquifers were greater than those found in other aquifers. Tetrachloroethylene, chloroform, trichloroethylene and 1,2-dichloropropane were the most frequently detected VOCs. However, they exceeded the guideline values proposed by the EU in only three aquifers located near to industrial and intense agricultural areas. PMID:18703213

Pecoraino, Giovannella; Scalici, Lea; Avellone, Giuseppe; Ceraulo, Leopoldo; Favara, Rocco; Candela, Esterina Gagliano; Provenzano, Maria Clara; Scaletta, Claudio

2008-07-24

225

Use of fugacity model to analyze temperature-dependent removal of micro-contaminants in sewage treatment plants.  

PubMed

Effluents from sewage treatment plants (STPs) are known to contain residual micro-contaminants including endocrine disrupting chemicals (EDCs) despite the utilization of various removal processes. Temperature alters the efficacy of removal processes; however, experimental measurements of EDC removal at various temperatures are limited. Extrapolation of EDC behavior over a wide temperature range is possible using available physicochemical property data followed by the correction of temperature dependency. A level II fugacity-based STP model was employed by inputting parameters obtained from the literature and estimated by the US EPA's Estimations Programs Interface (EPI) including EPI's BIOWIN for temperature-dependent biodegradation half-lives. EDC removals in a three-stage activated sludge system were modeled under various temperatures and hydraulic retention times (HRTs) for representative compounds of various properties. Sensitivity analysis indicates that temperature plays a significant role in the model outcomes. Increasing temperature considerably enhances the removal of ?-estradiol, ethinyestradiol, bisphenol, phenol, and tetrachloroethylene, but not testosterone with the highest biodegradation rate. The shortcomings of BIOWIN were mitigated by the correction of highly temperature-dependent biodegradation rates using the Arrhenius equation. The model predicts well the effects of operating temperature and HRTs on the removal via volatilization, adsorption, and biodegradation. The model also reveals that an impractically long HRT is needed to achieve a high EDC removal. The STP model along with temperature corrections is able to provide some useful insight into the different patterns of STP performance, and useful operational considerations relevant to EDC removal at winter low temperatures. PMID:21600629

Thompson, Kelly; Zhang, Jianying; Zhang, Chunlong

2011-05-19

226

Symptom clusters in a community with chronic exposure to chemicals in two superfund sites.  

PubMed

Sikes and French, Ltd., two National Priority List sites that are proximal to one another, are located approximately 20 mi (32 km) east of Houston, Texas. Dumping at Sikes occurred during the early 1960s and continued until 1967. Benzene, 1,2-dichloroethane, toluene, 1,1,2-trichloroethane, naphthalene, lead, fluorene, and pyrene are chemicals that pose a particular public health concern. French, Ltd., commenced operations in 1966, and dumping ceased in 1973. Chemicals of potential public health impact at the French, Ltd., site are benzene, benzo(a)anthracene, benzo(a)pyrene, copper, chrysene, chromium, dichlorodiphenyltrichloroethane, heptachlor, lead, nickel, polychlorinated biphenyls, tetrachloroethylene, trichloroethylene, and zinc. During the 1980s, both sites were placed on the National Priority List. Barrett Station is a stable black community located near the two sites. The question of whether levels of exposure to dumpsite chemicals were related to health complaints in the Barrett Station population was examined. The prevalence of 29 symptoms reported by 321 individuals who had been highly exposed was compared with symptoms reported by a group of 351 persons from the same community who had limited exposure. A meaningful difference between the two groups emerged for some of the symptoms, the most notable of which symptoms were neurologic. Almost twice as many subjects in the high-exposure group reported five or more neurologic symptoms, compared with the low-exposure group. This excess of neurological symptoms is consistent with the known toxic properties of the chemicals at the sites. PMID:7786046

Dayal, H; Gupta, S; Trieff, N; Maierson, D; Reich, D

227

Sanitary Landfill 1991 annual groundwater monitoring report  

SciTech Connect

The Savannah River Site (SRS) Sanitary Landfill is an approximately seventy acre site located just south of SRS Road C between the Savannah River Site's B-Area and Upper Three Runs Creek. Results from the first through third quarter 1991 groundwater monitoring date continue to show evidence of elevated levels of several hazardous constituents beneath the Sanitary Landfill: tritium, vinyl chloride, total radium, cadmium, 1,1,1-trichloroethane, 1,2 dichloroethane, 1,4 dichlorobenzene, trichloroethylene (TCE), tetrachloroethylene, and 1,1 dichloroethylene in excess of the primary drinking water standards were observed in at least one well monitoring the Sanitary Landfill during the third quarter of 1991. All of these constituents, except radium, were observed in the lower half of the original thirty-two acre site or the southern expansion site. Trichloroethylene and vinyl chloride are the primary organic contaminants in groundwater beneath the Sanitary Landfill. Vinyl chloride has become the primary contaminant during 1991. Elevated levels of benzene were consistently detected in LFW 7 in the past, but were not present in any LFW wells during the third quarter of 1991. A minor tritium plume is present in the central part of original thirty-two acre landfill. Elevated levels of tritium above the PDWS were consistently present in LFW 10A through 1991. This well has exhibited elevated tritium activities since the second quarter of 1989. Contaminant concentrations in the Sanitary Landfill are presented and discussed in this report.

Thompson, C.Y.; Norrell, G.T.; Bennett, C.B.

1992-02-01

228

Sanitary Landfill 1991 annual groundwater monitoring report  

SciTech Connect

The Savannah River Site (SRS) Sanitary Landfill is an approximately seventy acre site located just south of SRS Road C between the Savannah River Site`s B-Area and Upper Three Runs Creek. Results from the first through third quarter 1991 groundwater monitoring date continue to show evidence of elevated levels of several hazardous constituents beneath the Sanitary Landfill: tritium, vinyl chloride, total radium, cadmium, 1,1,1-trichloroethane, 1,2 dichloroethane, 1,4 dichlorobenzene, trichloroethylene (TCE), tetrachloroethylene, and 1,1 dichloroethylene in excess of the primary drinking water standards were observed in at least one well monitoring the Sanitary Landfill during the third quarter of 1991. All of these constituents, except radium, were observed in the lower half of the original thirty-two acre site or the southern expansion site. Trichloroethylene and vinyl chloride are the primary organic contaminants in groundwater beneath the Sanitary Landfill. Vinyl chloride has become the primary contaminant during 1991. Elevated levels of benzene were consistently detected in LFW 7 in the past, but were not present in any LFW wells during the third quarter of 1991. A minor tritium plume is present in the central part of original thirty-two acre landfill. Elevated levels of tritium above the PDWS were consistently present in LFW 10A through 1991. This well has exhibited elevated tritium activities since the second quarter of 1989. Contaminant concentrations in the Sanitary Landfill are presented and discussed in this report.

Thompson, C.Y.; Norrell, G.T.; Bennett, C.B.

1992-02-01

229

Modeling human exposure to hazardous-waste sites: A question of completeness  

SciTech Connect

In risk analysis, we use human-exposure assessments to translate contaminant sources into quantitative estimates of the amount of contaminant that comes in contact with human-environment boundaries, that is, the lungs, the gastrointestinal tract, and the skin surface of individuals within a specified population. An assessment of intake requires that we determine how much crosses these boundaries. Exposure assessments often rely implicitly on the assumption that exposure can be linked by simple parameters to ambient concentrations in air, water, and soil. However, more realistic exposure models require that we abandon such simple assumptions. To link contaminant concentrations in water, air, or soil with potential human intakes, we construct pathway-exposure factors (PEFs). For each PEF we combine information on environmental partitioning as well as human anatomy, physiology, and behavior patterns into an algebraic term that converts concentrations of contaminants into a daily intake per unit body weight in mg/kg-d for a specific route of exposure such as inhalation, ingestion, or dermal uptake. Using examples involving human exposure to either a radionuclide (tritium, {sup 3}H) or a toxic organic chemical (tetrachloroethylene, PCE) in soil, water, and air, we illustrate the use of PEFs and consider the implications for risk assessment. 12 refs., 4 tabs.

Daniels, J.I.; McKone, T.E.

1991-06-01

230

Health assessment for Lacks Industries, Inc. , Grand Rapids, Kent County, Michigan, Region 5. CERCLIS No. MID006014666. Preliminary report  

SciTech Connect

The Lacks Industries, Inc. site, in Grand Rapids, Michigan, has been delisted from the National Priorities List and is being regulated under the Resource Conservation and Recovery Act. Lacks Industries, Inc. discontinued electroplating operations and die casting for the automobile industry in July 1984 at the plant site. The plant is now used for painting and assembling of plastic parts for automobiles. Previously, plating wastes were discharged to two seepage ponds. It is reported that the prior owner (pre-1960) dumped trichloroethylene (TCE) and tetrachloroethylene (PCE) and metal solutions into a pit in the ground above which was built part of the Lacks Industries building. TCE and PCE were identified in all four downgradient monitoring wells with maximum concentrations of 17 parts per billion (ppb) and 89 ppb, respectively. Toluene (8 ppb), m-xylene (2 ppb) and cis-1,2-dichloroethylene (240 ppb) were each identified in one downgradient well. The two upgradient wells, which are supposed to represent background concentrations, had PCE concentrations of 67 ppb and 74 ppb. Several homes in the area had elevated concentrations of volatile organic compounds (VOCs), nickel, and total chromium. The site is of potential public health concern because of the risk to human health that could result from possible exposure to hazardous substances at levels that may result in adverse health effects over time.

Not Available

1989-04-10

231

Plume and lithologic profiling with surface resistivity and seismic tomography  

SciTech Connect

Improved surface-based geophysical technologies that are commercially available provide a new level of detail that can be used to guide ground water remediation. Surface-based multielectrode resistivity methods and tomographic seismic refraction techniques were used to image to a depth of approximately 30 m below the surface at the Natural and Accelerated Bioremediation Research Field Research Center. The U.S. Department of Energy (DOE) established the research center on the DOE Oak Ridge Reservation in Oak Ridge, Tennessee, to conduct in situ field-scale studies on bioremediation of metals and radionuclides. Bioremediation studies are being conducted on the saprolite, shale bedrock, and ground water at the site that have been contaminated with nitrate, uranium, technetium, tetrachloroethylene, and other contaminants (U.S. DOE 1997). Geophysical methods were effective in imaging the high-ionic strength plume and in defining the transition zone between saprolite and bedrock zones that appears to have a significant influence on contaminant transport. The geophysical data were used to help select the location and depth of investigation for field research plots. Drilling, borehole geophysics, and ground water sampling were used to verify the surface geophysical studies.

Watson, David B [ORNL; Doll, William E. [Battelle; Gamey, Jeff [Battelle; Sheehan, Jacob R [ORNL; Jardine, Philip M [ORNL

2005-03-01

232

Volatile chlorinated hydrocarbons in Antarctic superficial snow sampled during Italian ITASE expeditions.  

PubMed

In order to detect the presence of some volatile chlorinated hydrocarbons (VCHCs) and to understand their transport and deposition mechanism, superficial snow was sampled during two Italian ITASE (International Trans Antarctic Scientific Expedition) expeditions: the first traverse was carried out in 1998/1999 from Terra Nova Bay to Dome Concordia; the second traverse was carried out in 2001/2002 through Adélie, George V, Oates and Northern Victoria Lands. Some VCHCs (chloroform; 1,1,1-trichloroethane; tetrachloromethane; 1,1,2-trichloroethylene; tetrachloroethylene) were analysed using a highly sensitive and selective hyphenated technique composed of a purge-and-trap injector coupled to a gas chromatograph with a mass spectrometric detector (PTI-GC-MS) operating in SIM mode. Investigated VCHCs were present in all analysed snow samples with concentration levels of several units, tens, or sometimes hundreds of ng kg(-1). VCHC snow concentration levels remained approximately constant with changing distance from the coast and the comparison between fresh and aged snow did not show any substantial differences; on the basis of this evidence marine aerosol and dry deposition may be rejected as principal VCHC transport and deposition mechanism hypotheses. VCHC concentration levels in Antarctic snow samples were comparable to or greater than those found in snow from temperate zones. PMID:17287006

Zoccolillo, Lelio; Amendola, Luca; Cafaro, Claudia; Insogna, Susanna

2007-02-06

233

Carbonaceous sorbents for high-temperature interactive liquid chromatography of polyolefins.  

PubMed

The elution behavior of polyethylene (PE) and the three stereoisomers of polypropylene (PP) was studied on porous graphite along with three other carbon-based sorbents, carbon-clad zirconia particles, activated carbon, and exfoliated graphite in a systematic way in this work. Decahydronaphthalene, 1,2,3,4-tetrahydronaphthalene, 1,3,5-trimethylbenzene, tetrachloroethylene, xylene and p-xylene were used as mobile phases. While PE is adsorbed to various extents on all the tested carbonaceous sorbents from the majority of the solvents, PP is fully adsorbed only in selected cases. Testing alcohols (C7-C9) as mobile phase with Hypercarb™ indicates that all stereoisomers of PP are selectively adsorbed and desorbed when a solvent gradient alcohol?1,2,4-trichlorobenzene is used at 160°C. The retention of all stereoisomers of PP increases with the polarity of the alcohol. Linear PE is retained on Hypercarb™ even from 1,2-dichloro- and 1,2,4-trichlorobenzene, when a temperature below 120°C is applied, while it is not retained from these solvents at higher temperatures. All stereoisomeric forms of PP are not adsorbed under the same conditions. Some of the tested new sorbent/solvent systems have potential to be applied in routine analysis of industrially synthesised polyolefins. PMID:23616412

Chitta, Rajesh; Macko, Tibor; Brüll, Robert; Miller, Matthew; Cong, Rongjuan; deGroot, Willem

2013-07-01

234

D-area oil seepage basin bioventing optimization test plan  

SciTech Connect

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.

Berry, C.J.; Radway, J.C.; Alman, D.; Hazen, T.C.

1998-12-31

235

Isolation and properties of a 2-chlorovinylarsonic acid-degrading microorganism.  

PubMed

2-Chlorovinylarsonic acid (CVAOA) is a stable abiotic metabolite of lewisite 1 that has been identified in lewisite dumps. There have been no reports of microbial degradation of CVAOA, so we isolated and examined CVAOA-degrading microorganisms. CVAOA contains arsine, which is toxic to microbial growth. We therefore used the simple organic chemical, ethylene, as a sole carbon source in initial screening for suitable microbes. We isolated several microorganisms from sewage sludge and soil. Two strains, NK0505 and NK0506, could be grown on CVAOA as the sole carbon source and were identified by 16S rRNA sequencing as Nocardia carnea NK0505 and Rhodococcus opacus NK0506. Because N. carnea NK0505 was slightly more active in degrading CVAOA, we used it for further degradation studies. Strain NK0505 utilized about 90% of CVAOA (50 ppm) within 5 days; at higher concentrations of CVAOA no degradation occurred over a 10-day period. We identified 1-chloro-1,2-dihydroxyethane, ethylene glycol, glycolic acid, and arsenic acid as degradation products of CVAOA. Epoxy formation on alkylarsine was not confirmed. CVAOA is probably further metabolized via these compounds in the tricarboxylic acid cycle. Strain NK0505 could also degrade but-3-enylarsonic acid, trichloroethylene, isoprene, and 1,3-butadiene, but utilization of tetrachloroethylene and acetylene did not occur. PMID:19022568

Nakamiya, Kunichika; Nakayama, Takashi; Ito, Hiroyasu; Shibata, Yasuyuki; Morita, Masatoshi

2008-10-15

236

Savannah River Site A/M Area Southern Sector Characterization Cone Penetrometer Report  

SciTech Connect

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.

Raabe, B.A. [Westinghouse Savannah River Company, Aiken, SC (United States)

1993-05-01

237

A pilot study for delineation of areas contributing water to wellfields at Jackson, Tennessee  

USGS Publications Warehouse

The U.S. Geological Survey, in cooperation with the Tennessee Department of Health and Environment, Division of Groundwater Protection, and the Jackson Utility Division, conducted a pilot study to determine data needs and the applicability of four methods for the delineation of wellhead protection areas. Jackson Utility Division in Jackson, Madison County, Tennessee, pumps about 9 million gallons of ground water daily from two municipal wellfields that tap an unconfined sand aquifer. Under natural hydraulic gradients, ground waterflows southward toward the South Wellfield at approximately 2 to 3 feet per day; natural flow toward the North Wellfield from the east at 1 to 2 feet per day. Water quality generally is suitable for most uses. Concentrations of dissolved solids are low, and excessive iron is the only significant naturally occurring water-quality problem. However, trace concentrations of volatile organic compounds have been detected in water pumps from the South Wellfield; the highest concentration of a single compound has been 23 micrograms per liter of tetrachloroethylene. Potential sources of ground-water contamination in the Jackson area include a hazardous-waste site, municipal and industrial landfill, and underground-storage tanks. Some of the four method for delineating wellhead protection areas did not adequately describe zones contributing flow to the wellfields. Calculations based on a uniform flow equation provided a preliminary delineation of zones of contribution for the wellfields and ground-water time-of-travel contours. Limitations of the applied methods motivated the design of a more rigorous hydrogeologic investigation.

Broshears, R. E.; Connell, J. F.; Short, N. C.

1991-01-01

238

Chlorination byproducts induce gender specific autistic-like behaviors in CD-1 mice.  

PubMed

In 2000, the Agency for Toxic Substances and Disease Registry (ATSDR) released a report concerning elevated autism prevalence and the presence water chlorination byproducts in the municipal drinking water supply in Brick Township, New Jersey. The ATSDR concluded that it was unlikely that these chemicals, specifically chloroform, bromoform (Trihalomethanes; THMs) and tetrachloroethylene (Perchloroethylene; PCE) had contributed to the prevalence of autism in this community based upon correlations between timing of exposure and/or concentration of exposure. The ATSDR conclusion may have been premature, as there is no conclusive data evidencing a correlation between a particular developmental time point that would render an individual most susceptible to toxicological insult with the development of autism. Therefore, it was our aim to determine if these chemicals could contribute to autistic like behaviors. We found that males treated with THMs and PCE have a significant reduction in the number of ultrasonic vocalizations (USVs) emitted in response to maternal separation, which are not attributed to deficits in vocal ability to or to lesser maternal care. These same males also show significantly elevated anxiety, an increase in perseverance behavior and a significant reduction in sociability. The sum of our data suggests that male, but not female mice, develop autistic like behaviors after gestational and postnatal exposure to the aforementioned chemical triad via drinking water. We believe development of such aberrant behaviors likely involves GABAergic system development. PMID:21740927

Guariglia, Sara Rose; Jenkins, Edmund C; Chadman, Kathryn K; Wen, Guang Y

2011-06-29

239

Analytical Modeling of Contaminant Transport with Convergent Reactions  

NASA Astrophysics Data System (ADS)

In this presentation, we provide analytical solutions for reactive transport with convergent reactions using the singular value decomposition approach. We consider a reaction network in which a compound reacts to form multiple daughter products, which further react to a single granddaughter. This reaction scheme is illustrated by the dechlorination of tetrachloroethylene (PCE) and trichloroethylene (TCE). PCE reacts to produce TCE and TCE reacts to form three daughter products, cis-1,2-dichloroethylene (cis-1,2-DCE), trans-1,2-dichloroethylene (trans-1,2-DCE), and 1,1-dichloroethylene (1,1-DCE). Three DCEs will further react to form the same product, vinyl chloride (VC). Finally, VC reacts to produce ethene (ETH). In achieving the analytical solution, all reactions are assumed to be first-order. Because the partial differential equation describing the reactive transport of a compound may be coupled by multiple reactant concentrations, currently the problem must be solved numerically. We analytically conduct the singular value decomposition and decouple the system of transport equations with convergent reactions into orthogonal (independent) subsystems. Previously published analytical solutions become the basic solutions in the transformed domain for each independent subsystem. The solutions in real concentration domain are obtained using the inverse transform.

Sun, Y.; Buscheck, T. A.; Lu, X.

2002-12-01

240

Risk communication: Health risks associated with environmentally contaminated private wells versus chloroform in a public water supply  

SciTech Connect

During March 1988, 16 private wells in Sault St. Marie, Michigan, were found to be contaminated with one or more environmental contaminants. Risk assessments for carcinogens (benzene, 1,2-dichloroethane, dichloromethane, trichloroethylene, and tetrachloroethylene) were formulated. The maximum concentration of chloroform in the city public water supply was 26 [mu]g/L. The relative health risk from the consumption of chlorinated surface water from the public water supply system would be approximately 4.3 times greater compared to that of consuming groundwater from the contaminated private wells. The affected residents were given three options: (a) continue consumption of bottled water; (b) connection to the existing public water supply system; or (c) construction of deep water wells. The citizens voted for the second option of connecting to the public water supply system and voluntarily accepted the relatively higher health risk. The State of Michigan later proposed to further improve the water purity by upgrading the public water supply system by the incorporation of a filtration plant. The project was completed in August 1993.

Sidhu, K.S.; Chadzynski, L. (Michigan Dept. of Public Health, Lansing, MI (United States))

1994-06-01

241

FIELD SCREENING FOR HALOGENATED VOLATILE ORGANIC COMPOUNDS  

SciTech Connect

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.

John F. Schabron; Joseph F. Rovani Jr.; Theresa M. Bomstad

2002-06-01

242

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

SciTech Connect

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.

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

1993-04-01

243

Evaluation of a passive sampler for volatile organic compounds at ppb concentrations, varying temperatures, and humidities with 24-h exposures. 2. Sampler performance  

SciTech Connect

The performance of the 3M 3520 organic vapor monitor (OVM) as a tool for monitoring inhalation exposures to volatile organic compounds (VOCs) in nonoccupational community environments was evaluated by using combined controlled test atmospheres of benzene, 1,3-butadiene, carbon tetrachloride, chloroform, 1,4-dichlorobenzene, methylene chloride, styrene, tetrachloroethylene, and toluene. Eight OVMs were simultaneously exposed to concentrations of 10,20, and 200 {micro}g/m{sup 3} in combination with temperatures of 10, 25, and 40 C and relative humidities of 12, 50, and 90% for 24 H. The results of this study indicate that the performance of the 3520 OVM is compound-specific and depends on concentration, temperature, and humidity. With the exception of 1,3-butadiene under most conditions and styrene and methylene chloride at very high relative humidities, recoveries showed a negative bias as compared to calculated chamber concentrations but were generally within {+-}25% of theory, indicating that the 3520 OVM can be effectively used over the range of concentrations and environmental conditions tested with a 24-h sampling period. Increasing humidities resulted in increasing negative bias from full recovery. Reverse diffusion experiments conducted at 200 {micro}g/m{sup 3} and five temperature/humidity combinations indicated diffusion losses only for 1,3-butadiene, methylene chloride, and styrene under increased humidity conditions. The recovery rates reported in this study can be used for estimating measurement biases when using OVMs for indoor, outdoor, and personal air monitoring of VOCs in community environments.

Chung, C.W.; Morandi, M.T.; Stock, T.H.; Afshar, M.

1999-10-15

244

Evaluation of a passive sampler for volatile organic compounds at ppb concentrations, varying temperatures, and humidities with 24-h exposures. 1. Description and characterization of exposure chamber system  

SciTech Connect

A dynamic exposure chamber was constructed to evaluate the performance of the 3M 3520 organic vapor monitor when exposed during 24 h to combined test atmospheres of benzene, 1,3-butadiene, carbon tetrachloride, chloroform, 1,3-dichlorobenzene, methylene chloride, styrene, tetrachloroethylene, and toluene at target concentrations of 10, 20, and 200 {micro}g/m{sup 3} in combination with temperatures of 10, 25, and 40 C and relative humidities of 12, 50, and 90%. These conditions are generally representative of the range of community air environments, both indoor and outdoor. The system consists of five distinct units: (1) dilution air delivery, (2) humidification, (3) VOC generation and delivery, (4) mixing chamber, and (5) exposure chamber. High-emission permeation tubes were utilized to generate the target VOCs. Both the target temperatures and humidities were achieved and maintained for multiple consecutive days. The variation of the temperature in the exposure chamber was controlled within {+-}1 C, while relative humidity was controlled within {+-}1.5% at 12% RH, {+-}2% at 50% RH, and {+-}3% at 90% RH. Under constant preset temperatures and stable nitrogen flow through the VOC generation unit, various temporal patterns of permeation rates were observed over time. The lifetimes and permeation rates of the tubes differed by compound, length of the tube, and manufacturer.

Chung, C.W.; Morandi, M.T.; Stock, T.H.; Afshar, M.

1999-10-15

245

Sources and sinks of acetone, methanol, and acetaldehyde in North Atlantic marine air  

NASA Astrophysics Data System (ADS)

Measurements of acetone, methanol, acetaldehyde and a range of non-methane hydrocarbons have been made in North Atlantic marine air at the Mace Head observatory. Under maritime conditions the combination of OVOCs (acetone, methanol and acetaldehyde) contributed up to 85% of the total mass of measured non methane organics in air and up to 80% of the OH radical organic sink, when compared with the sum of all other organic compounds including non-methane hydrocarbons, DMS and OH-reactive halocarbons (trichloromethane and tetrachloroethylene). The observations showed anomalies in the variance and abundance of acetaldehyde and acetone over that expected for species with a remote terrestrial emission source and OH controlled chemical lifetime. A detailed model incorporating an explicit chemical degradation mechanism indicated in situ formation during air mass transport was on timescales longer than the atmospheric lifetime of precursor hydrocarbons or primary emission. The period over which this process was significant was similar to that of airmass motion on intercontinental scales, and formation via this route may reproduce that of a widespread diffuse source. The model indicates that continued short chain OVOC formation occurs many days from the point of emission, via longer lived intermediates of oxidation such as organic peroxides and long chain alcohols.

Lewis, A. C.; Hopkins, J. R.; Carpenter, L. J.; Stanton, J.; Read, K. A.; Pilling, M. J.

2005-08-01

246

Sources and sinks of acetone, methanol, and acetaldehyde in North Atlantic air  

NASA Astrophysics Data System (ADS)

Measurements of acetone, methanol, acetaldehyde and a range of non-methane hydrocarbons have been made in North Atlantic marine air at the Mace Head observatory. Under maritime conditions the combination of OVOCs (acetone, methanol and 5 acetaldehyde) contributed up to 85% of the total mass of measured non methane organics in air and up to 80% of the OH radical organic sink, when compared with the sum of all other organic compounds including non-methane hydrocarbons, DMS and OH-reactive halocarbons (trichloromethane and tetrachloroethylene). The observations showed anomalies in the variance and abundance of acetaldehyde and acetone 10 over that expected for species with a remote terrestrial emission source and OH controlled chemical lifetime. A detailed model incorporating an explicit chemical degradation mechanism indicated in situ formation during air mass transport was on timescales longer than the atmospheric lifetime of precursor hydrocarbons or primary emission. The period over which this process was significant was similar to that of airmass mo15 tion on intercontinental scales, and formation via this route may reproduce that of a widespread diffuse source. The model indicates that continued short chain OVOC formation occurs many days from the point of emission, via longer lived intermediates of oxidation such as organic peroxides and long chain alcohols.

Lewis, A. C.; Hopkins, J. R.; Carpenter, L. J.; Stanton, J.; Read, K. A.; Pilling, M. J.

2005-03-01

247

Preliminary Engineering Report contaminated groundwater seeps 317/319/ENE area  

SciTech Connect

When the Resource Conservation and Recovery Act Facility Investigation (RFI) in the 317/319/ENE Area of Argonne National Laboratory-East (ANL-E) was being completed, groundwater was discovered moving to the surface through a series of seeps. The seeps are located approximately 600 ft south of the ANL fence line in Waterfall Glen Forest Preserve. Samples of this water were collected and analyzed for selected parameters. Two of five seeps sampled were found to contain detectable levels of organic contaminants. Three chemical species were identified: chloroform (14-25 {mu}g/L), carbon tetrachloride (56-340 {mu}g/L), and tetrachloroethylene (3-6 {mu}g/L). The other seeps did not contain detectable levels of volatile organic compounds (VOCs). The water issuing from these two contaminated seeps flows into a narrow ravine, where it is visible as a trickle of water flowing through sand and gravel deposits on the floor of the ravine. Approximately 100-ft downstream of the seep area, the contaminated water is no longer visible, having drained back into the soil in the bed of the ravine. Figure 1 shows the location of the 317/319/ENE Area in relation to the ANL-E site and the Waterfall Glen Forest Preserve.

NONE

1996-10-01

248

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

SciTech Connect

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

McKone, T.E.; Daniels, J.I. (Lawrence Livermore National Laboratory, Livermore (USA))

1991-02-01

249

Quantifying volatile organic compounds in porous media: effects of sampling method attributes, contaminant characteristics and environmental conditions.  

PubMed

Understanding how sampling methods can impact the accuracy of volatile organic compound (VOC) measurements in samples of soil and subsurface porous media is often critical to sound decision making during characterization and remediation of VOC contaminated sites. In this study, the accuracy of VOC measurements was investigated using an experimental apparatus packed with sandy porous media and contaminated with known levels of VOCs, which could be sampled using different methods under variable, but controlled, conditions. Five sampling methods were examined representing different degrees of porous media disaggregation and duration of atmospheric exposure (MDE) that can occur during sample acquisition and preservation in the field. Three pervasive VOCs were studied (1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene) at low and high concentration levels. Five porous media temperatures were examined ranging from 5 to 80 degrees C to represent ambient or thermal remediation conditions and two water saturation levels were used to mimic vadose zone and groundwater zone conditions. The results of this research demonstrated that sampling method attributes can impact the accuracy of VOC measurements in porous media by causing negative bias in VOC concentration data ranging from near 0 to 90% or more. The magnitude of the negative bias is dependent on the attributes of the sampling method used (i.e., level of MDE) and interactions with key contaminant properties and environmental conditions (i.e., VOC KH, porous media temperature, water saturation level). PMID:19475967

Oesterreich, Ryan C; Siegrist, Robert L

2009-04-15

250

Membrane-extraction ion mobility spectrometry for in situ detection of chlorinated hydrocarbons in water.  

PubMed

Membrane-extraction ion mobility spectrometry (ME-IMS) has been developed for in situ sampling and analysis of trace chlorinated hydrocarbons in water in a single procedure. The sampling is configured so that aqueous contaminants permeate through a spiral hollow poly(dimethylsiloxane) (PDMS) membrane and are carried away by a vapor flow through the membrane tube. The extracted analyte flows into an atmospheric-pressure chemical-ionization (APCI) chamber and is analyzed in a specially made IMS analyzer. The PDMS membrane was found to effectively extract chlorinated hydrocarbon solvents from the liquid phase to vapor. The specialized IMS analyzer has measured resolutions of R = 33 and 41, respectively, for negative- and positive-modes and is capable of detecting aqueous tetrachloroethylene (PCE) and trichloroethylene (TCE) as low as 80 and 74 microg/L in the negative ion mode, respectively. The time-dependent characteristics of sampling and detection of TCE are both experimentally and theoretically studied for various concentrations, membrane lengths, and flow rates. These characteristics demonstrate that membrane-extraction IMS is feasible for the continuous monitoring of chlorinated hydrocarbons in water. PMID:20334385

Du, Yongzhai; Zhang, Wei; Whitten, William; Li, Haiyang; Watson, David B; Xu, Jun

2010-05-15

251

[Preparation of a novel activated carbon coating fiber for solid phase micro-extraction and its application for halocarbon compound analysis in water].  

PubMed

A novel activated carbon coating fiber used for solid phase micro-extraction (SPME) was prepared using activated carbon powder and silica resin adhesive. The extraction properties of the novel activated carbon coating fiber were investigated. The results indicate that this coating fiber has high concentration ability, with enrichment factors for chloroform, carbon tetrachloride, trichloroethylene and tetrachloroethylene in the range of 13.8 to 18.7. The fiber is stable at temperature as high as 290 degrees C and it can be used for over 140 times at 250 degrees C. The activated carbon coating fiber was then applied to the analysis of the four halocarbon compounds mentioned above. A linear correlation with correlation coefficients between 0.995 2 and 0.999 4 and the detection limits between 0.008 and 0.05 microg/L were observed. The method was also applied to a real water sample analysis and the recoveries of these halocarbon compounds were from 95.5% to 104.6%. PMID:15706948

Wang, Shutao; Wang, Yan; You, Hong; Liang, Zhihua

2004-09-01

252

Time scales of DNAPL migration in sandy aquifers examined via numerical simulation  

SciTech Connect

The time required for dense nonaqueous phase liquid (DNAPL) to cease migrating following release to the subsurface is a valuable component of a site conceptual model. This study uses numerical simulation to investigate the migration of six different DNAPLs in sandy aquifers. The most influential parameters governing migration cessation time are the density and viscosity of the DNAPL and the mean hydraulic conductivity of the aquifer. Releases of between 1 and 40 drums of chlorinated solvent DNAPLs, characterized by relatively high density and low viscosity, require on the order of months to a few years to cease migrating in a heterogeneous medium sand aquifer having an average hydraulic conductivity of 7.4 x 10{sup -3} cm/s. In contrast to this, the release of 20 drums of coal tar {rho}{sub D} = 1061 kg/m{sup 3}, {mu}{sub D} = 0.161 Pa(.)s) requires more than 100 years to cease migrating in the same aquifer. Altering the mean hydraulic conductivity of the aquifer results in a proportional change in cessation times. Parameters that exhibit relatively little influence on migration time scales are the DNAPL-water interfacial tension, release volume, source capillary pressure, mean aquifer porosity, and ambient ground water hydraulic gradient. This study also demonstrates that low-density DNAPLs (e.g., coal tar) give rise to greater amounts of lateral spreading and greater amounts of pooling on capillary barriers than high-density DNAPLs such as trichloroethylene or tetrachloroethylene.

Gerhard, J.I.; Pang, T.; Kueper, B.H. [University of Edinburgh, Edinburgh (United Kingdom). Inst. of Infrastructure & Environmental

2007-03-15

253

Aerobic/anaerobic/aerobic sequenced biodegradation of a mixture of chlorinated ethenes, ethanes and methanes in batch bioreactors.  

PubMed

A novel aerobic/anaerobic/aerobic treatment was implemented in batch reactors containing aquifer materials from a site contaminated by tetrachloroethylene (PCE), trichloroethylene (TCE), vinyl chloride (VC), 1,1,2-trichloroethane (1,1,2-TCA) and chloroform (CF). Consortia grown aerobically on methane, propane, n-pentane and n-hexane completely biodegraded the chlorinated solvent mixture, via aerobic cometabolism of VC, CF, TCE and 1,1,2-TCA, followed by PCE reductive dechlorination (RD) to 1,2-cis-dichlorothylene (cis-DCE) or TCE, and cis-DCE/TCE cometabolism in a further aerobic phase. n-Hexane was the best substrate. No electron donor was supplied for RD, which likely utilized cellular material produced during the aerobic phase. Chloride release was stoichiometric with chlorinated solvent biodegradation. According to the Lepidium sativum ecotoxicity test, a decreased toxicity was observed with propane, n-pentane and n-hexane, but not methane. A kinetic study of PCE RD allowed to estimate the PCE maximum specific rate (0.57 ± 0.07 mg mg(protein)(-1) day(-1)) and half-saturation constant (6.7 ± 1.5 mg L(-1)). PMID:23201903

Frascari, Dario; Fraraccio, Serena; Nocentini, Massimo; Pinelli, Davide

2012-10-17

254

An evaluation of employee exposure to volatile organic compounds in three photocopy centers.  

PubMed

Personal and area samples from three copy centres were collected in thermal desorption tubes and analyzed using gas chromatography-mass spectrometry. Real-time personal total volatile organic compounds (TVOC) were measured using a data-logging photoionization detector. Fifty-four different VOCs were detected in the area samples. The maximum concentration measured was 1132.0 ppb (toluene, copy center 3, day 1). Thirty-eight VOCs were detected in the personal samples and concentrations ranged from 0.1 ppb (1,1-biphenyl, p-dichlorobenzene, propylbenzene, styrene, and tetrachloroethylene) to 689.6 ppb (toluene). Real-time TVOC measurements indicated daily fluctuations in exposure, ranging from <71 to 21,300 ppb. The time-weighted average exposures for the photocopier operators on days 1 and 2 were 235 and 266 ppb and 6155 and 3683 ppb, in copy centers 2 and 3, respectively. Personal exposure measurements of individual VOCs were below accepted occupational standards and guidelines. For example, the maximum concentration was 0.3% of the permissible exposure limits (toluene, copy center 3). Exposures were highest in copy center 3; this is likely due to the presence of offset printing presses. It is concluded that photocopiers contribute a wide variety of VOCs to the indoor air of photocopy centers; however, exposures are at least 100 times below established standards. PMID:10856189

Stefaniak, A B; Breysse, P N; Murray, M P; Rooney, B C; Schaefer, J

2000-06-01

255

F-Area seepage basins, groundwater quality assessment report, first quarter 1990  

SciTech Connect

During the first quarter of 1990, wells which make up the F-Area Seepage Basins (F-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, gross alpha, and nonvolatile beta. The primary contaminants observed at wells monitoring the F-Area Seepage Basins are tritium, nitrate, cadmium, lead, total radium, gross alpha, and nonvolatile beta. Concentrations of at least one of the following constituents: tritium, nitrate, total radium, gross alpha, cadmium, lead, tetrachloroethylene, nonvolatile beta, endrin, lindane, barium, fluoride, mercury, and trichlorethylene in excess of the primary drinking water standard (PDWS) were observed in at least one well monitoring the F-Area Seepage Basins. Tritium concentrations above the PDWS occur in forty-four of the fifty-nine (75%) groundwater monitoring wells. Nitrate concentrations above the PDWS occur in thirty-four of the fifty-nine (59%) groundwater wells. The radionuclides, total radium, gross alpha, and nonvolatile beta, exceed the PDWS is over twenty-five percent of the groundwater wells. Heavy metals, cadmium and lead in particular, exceed the PDWS in over twelve percent of the wells. Since 1987, tritium and nitrate concentrations have been steadily declining in a majority of the wells. However, tritium concentrations, from fourth quarter 1989 to first quarter 1990, have increased.

Not Available

1990-06-01

256

Superfund Record of Decision (EPA Region 10): Ponders Corner Site, Washington (second remedial action), September 1985. Final report  

SciTech Connect

Ponders Corner, or the Lakewood site as it is identified in the National Priorities List, is located in Pierce County, Washington, south of the city of Tacoma. In July 1981, EPA sampled drinking water wells in the Tacoma, WA area for contamination with purgeable halocarbons. The sampling showed that Lakewood Wells H1 and H2 were contaminated with 1,2-dichloroethylene (1,2 DCE), trichloroethylene (TCE), and tetrachloroethylene. In mid-August 1981 Lakewood water district took wells H1 and H2 out of production. It was determined that the septic tanks and the ground-disposal area of a commercial cleaners were the probable source of well-water contamination. Solvents used in the dry cleaning process were disposed in the septic tank and liquid wastes consisting of solvent-contaminated sludges and water draw-off were disposed on the ground outside the cleaners. Initial Remedial Measures (IRMs) implemented in June 1984 at the site included the construction of air stripping towers for wells H1 and H2. The recommended alternative for this second remedial action are included.

Not Available

1985-09-30

257

Destruction of organic compounds in water using supported photocatalysts  

SciTech Connect

Photocatalytic destruction of organic compounds in water is investigated using tanning lamps and fixed-bed photoreactors. Platinized titanium dioxide (Pt-TiO{sub 2}) supported on silica gel is used as a photocatalyst. Complete mineralization of influent concentrations of 4.98 mg/L tetrachloroethylene and 2.35 mg/L p-dichlorobenzene requires a reactor residence time less than 1.3 minutes. While for influent concentrations of 3.58 mg/L 2-chlorobiphenyl, 2.50 mg/L methyl ethyl ketone and 0.49 mg/L carbon tetrachloride, complete mineralization requires reactor residence times of 1.6, 10.5, and 16.8 minutes, respectively. A reactor model is developed using Langmuir-Hinshelwood kinetics and the model parameters are determined using a reference compound, trichloroethylene. Based on the results of experiments with trichloroethylene, the model predicts the mineralization of the aforementioned compounds from ultraviolet (UV) irradiance, influent concentration, hydroxyl radical rate constants, and the known physical properties of the compounds. The model is also able to predict organic destruction using solar insolation (which has a different spectral distribution from the tanning lamps) based on the UV absorption characteristics of titanium dioxide.

Zhang, Y.; Crittenden, J.C.; Hand, D.W.; Perram, D.L. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Civil and Environmental Engineering

1996-05-01

258

Simulated formation and flow of microemulsions during surfactant flushing of contaminated soil.  

PubMed

Contamination of groundwater resources by non-aqueous phase liquids (NAPLs) has become an issue of increasing environmental concern. This study investigated the formation and flow of microemulsions during surfactant flushing of NAPL-contaminated soil using the finite difference model UTCHEM, which was verified with our laboratory experimental data. Simulation results showed that surfactant flushing of NAPLs (i.e., trichloroethylene and tetrachloroethylene) from the contaminated soils was an emulsion-driven process. Formation of NAPL-in-water microemulsions facilitated the removal of NAPLs from contaminated soils. Changes in soil saturation pressure were used to monitor the mobilization and entrapment of NAPLs during surface flushing process. In general, more NAPLs were clogged in soil pores when the soil saturation pressure increased. Effects of aquifer salinity on the formation and flow of NAPL-in-water microemulsions were significant. This study suggests that the formation and flow of NAPL-in-water microemulsions through aquifer systems are complex physical-chemical phenomena that are critical to effective surfactant flushing of contaminated soils. PMID:11766810

Ouyan, Ying; Cho, Jong Soo; Mansell, Robert S

2002-01-01

259

Sanitary Landfill Groundwater Monitoring Report, Fourth Quarter 1999 and 1999 Summary  

SciTech Connect

A maximum of thirty eight-wells of the LFW series monitor groundwater quality in the Steed Pond Aquifer (Water Table) beneath the Sanitary Landfill Area at the Savannah River Site (SRS). These wells are sampled quarterly to comply with the South Carolina Department of Health and Environmental Control Domestic Water Permit DWP-087A and as part of the SRS Groundwater Monitoring Program. Iron (Total Recoverable), Chloroethene (Vinyl Chloride) and 1,1-Dichloroethane were the most widespread constituents exceeding the Final Primary Drinking Water Standards during 1999. Trichloroethylene, 1,1-Dichloroethylene, 1,2-Dichloroethane, 1,4-Dichlorobenzene, Aluminum (Total Recoverable), Benzene, cis-1,2-Dichloroethylene, Dichlorodifluoromethane, Dichloromethane (Methylene Chloride), Gross Alpha, Mercury (Total Recoverable), Nonvolatile Beta, Tetrachloroethylene, Total Organic Halogens, Trichlorofluoromethane, Tritium also exceeded standards in one or more wells. The groundwater flow direction in the Steed Pond Aquifer (Water Table) beneath the Sanitary Landfill is to the southeast (universal transverse Mercator coordinates). The flow rate in this unit was approximately 144.175 ft/year during first quarter 1999 and 145.27 ft/year during fourth quarter 1999.

Chase, J.

2000-03-13

260

Removal and destruction of organic compounds in water using adsorption, steam regeneration, and photocatalytic oxidation processes  

SciTech Connect

A treatment strategy is examined whereby organic compounds in the aqueous phase are first removed by fixed-bed adsorption, followed by off-line regeneration of spent adsorbent using saturated steam (160 C) and cleanup of steam condensate using fixed-bed photocatalysis. This treatment strategy is examined with the following organic compounds: tetrachloroethylene (PCE), carbon tetrachloride (CCl{sub 4}), p-dichlorobenzene (p-DCB), o-chlorobiphenyl (o-PCB), and methyl ethyl ketone (MEK). For six cycles of adsorption and regeneration, the steaming process is effective to regenerate the adsorbent exhausted with PCE, p-DCB, CCl{sub 4}, or MEK. In the case of o-PCB, there is about 20% loss in adsorbent capacity after the first cycle; however, the adsorption capacity for Cycles 2-6 is almost the same. Fixed-bed photocatalysis is examined for decontamination of steam condensate carrying the desorbed organics, and it is observed to be effective for mineralization of aqueous phase PCE, p-DCB, CCl{sub 4}, and o-PCB. In the case of MEK, although 97% of the compound was removed, only 16% removal of total organic carbon was observed, thereby suggesting that some by-products were produced that were refractory to oxidation.

Suri, R.P.S. [Villanova Univ., PA (United States). Dept. of Civil and Environmental Engineering; Crittenden, J.C.; Hand, D.W. [Michigan Technological Univ., Houghton, MI (United States). Dept. of Civil and Environmental Engineering

1999-10-01

261

Current Intelligence Bulletins: summaries  

SciTech Connect

Summaries are provided for the 47 Current Intelligence Bulletins issued to date by NIOSH; any revisions in NIOSH policy made after a bulletin was issued are included. Subjects of the bulletins include the following: chloroprene; trichloroethylene; ethylene-dibromide; chrome pigment; asbestos exposure; hexamethylphosphoric-triamide; polychlorinated biphenyls; 4,4'-diaminodipheylmethane; chloroform; radon daughters; dimethylcarbamoyl-chloride; diethylcarbamoyl-chloride; explosive azide hazard; inorganic arsenic; nitrosamines; metabolic precursors of beta-naphtylamine; 2-nitropropane; acryonitrile; 2,4-diaminoanisole; tetrachloroethylene; trimellitic-anhydride; ethylene-thiourea; ethylene-dibromide and disulfiram, toxic interaction; direct blue 6, direct black 38, direct brown 95, benzidine derived dyes; ethylene-dichloride; NIAX catalyst ESN; chloroethanes, review of toxicity; vinyl halides, carcinogenicity; glycidyl ethers; epichlorohydrin; smoking and the occupational environment; arsine poisoning in the workplace; radiofrequency sealers and heaters; formaldehyde; ethylene-oxide; silica flour; ethylene-dibromide; vibration syndrome; glycol ethers; 2,3,7,8-tetrachlorodibenzo-p-dioxin; 1,3-butadiene; cadmium; monohalomethanes; dinitrotoluenes; polychlorinated biphenyls in electrical equipment fires or failures; methylene-chloride; and 4,4' methylenedianiline.

Not Available

1986-07-24

262

Test plan for Geo-Cleanse{reg_sign} demonstration (in situ destruction of dense non-aqueous phase liquid (DNAPL))  

SciTech Connect

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.

Jerome, K.M.; Looney, B.B.; Accorsi, F.; Dingens, M.; Wilson, J.T.

1996-09-01

263

Field test of single well DNAPL characterization using alcohol injection/extraction  

SciTech Connect

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.

Jerome, K.M.; Looney, B.B.; Rhoden, M.L.; Riha, B.; Burdick, S. [Westinghouse Savannah River Co., Aiken, SC (United States)

1996-10-29

264

Surface acoustic wave sensors/gas chromatography; and Low quality natural gas sulfur removal and recovery CNG Claus sulfur recovery process  

SciTech Connect

This topical report consists of the two titled projects. Surface Acoustic Wave/Gas Chromatography (SAW/GC) provides a cost-effective system for collecting real-time field screening data for characterization of vapor streams contaminated with volatile organic compounds (VOCs). The Model 4100 can be used in a field screening mode to produce chromatograms in 10 seconds. This capability will allow a project manager to make immediate decisions and to avoid the long delays and high costs associated with analysis by off-site analytical laboratories. The Model 4100 is currently under evaluation by the California Environmental Protection Agency Technology Certification Program. Initial certification focuses upon the following organics: cis-dichloroethylene, chloroform, carbon tetrachloride, trichlorethylene, tetrachloroethylene, tetrachloroethane, benzene, ethylbenzene, toluene, and o-xylene. In the second study the CNG Claus process is being evaluated for conversion and recovery of elemental sulfur from hydrogen sulfide, especially found in low quality natural gas. This report describes the design, construction and operation of a pilot scale plant built to demonstrate the technical feasibility of the integrated CNG Claus process.

Klint, B.W.; Dale, P.R.; Stephenson, C.

1997-12-01

265

Predicting Optimal Resolving Power for Ambient Pressure Ion Mobility Spectrometry (IMS)  

PubMed Central

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.

Kanu, Abu B.; Gribb, Molly M.; Hill, Herbert H

2010-01-01

266

Microwave-swing adsorption to capture and recover vapors from air streams with activated carbon fiber cloth.  

PubMed

Adsorption with regeneration is a desirable means to control the emissions of organic vapors such as hazardous air pollutants (HAPs) and volatile organic compounds (VOCs) from air streams as it allows for capture, recovery, and reuse of those VOCs/HAPS. Integration of activated-carbon fiber-cloth (ACFC) adsorbent with microwave regeneration provides promise as a new adsorption/ regeneration technology. This research investigates the feasibility of using microwaves to regenerate ACFC as part of a process for capture and recovery of organic vapors from gas streams. A bench-scale fixed-bed microwave-swing adsorption (MSA) system was built and tested for adsorption of water vapor, methyl ethyl ketone (MEK), and tetrachloroethylene (PERC) from an airstream and then recovery of those vapors with microwave regeneration. The electromagnetic heating behavior of dry and vapor-saturated ACFC was also characterized. The MSA system successfully adsorbed organic vapors from the airstreams, allowed for rapid regeneration of the ACFC cartridge, and recovered the water and organic vapors as liquids. PMID:16190249

Hashisho, Zaher; Rood, Mark; Botich, Leon

2005-09-01

267

Evaluation of geophysical methods for the detection of subsurfacetetracgloroethyene in controlled spill experiments  

SciTech Connect

A controlled Tetrachloroethylene (PCE) spill experiment was conducted in a multi-layer formation consisting of sand and clayey-sandlayers. The purpose of the work was to determine the detection limits and capability of various geophysical methods. Measurements were made with ten different geophysical techniques before, during, and after the PCE injection. This experiment provided a clear identification of any geophysical anomalies associated with the presence of the PCE. During the injection period all the techniques indicated anomalies associated with the PCE. In order to quantify the results and provide an indication of the PCE detection limits of the various geophysical methods, the tank was subsequently excavated and samples of the various layers were analyzed for residual PCE concentration with gas chromatography (GC). This paper presents some of the results of five of the techniques: cross borehole complex resistivity (CR) also referred to as spectral induced polarization (SIP), cross borehole high resolution seismic (HRS), borehole self potential (SP), surface ground penetration radar (GPR), and borehole video (BV).

Mazzella, Aldo; Majer, Ernest L.

2006-04-10

268

The Site of Oxygen Limitation in Soybean Nodules1  

PubMed Central

In legume nodules the [O2] in the infected cells limits respiration and nitrogenase activity, becoming more severe if nodules are exposed to subambient O2 levels. To identify the site of O2 limitation, adenylate pools were measured in soybean (Glycine max) nodules that were frozen in liquid N2 before being ground, lyophilized, sonicated, and separated on density gradients of nonaqueous solvents (heptane/tetrachloroethylene) to yield fractions enriched in bacteroid or plant components. In nodules maintained in air, the adenylate energy charge (AEC = [ATP + 0.5 ADP]/[ATP + ADP + AMP]) was lower in the plant compartment (0.65 ± 0.04) than in the bacteroids (0.76 ± 0.095), but did not change when the nodulated root system was exposed to 10% O2. In contrast, 10% O2 decreased the bacteroid AEC to 0.56 ± 0.06, leading to the conclusion that they are the primary site of O2 limitation in nodules. To account for the low but unchanged AEC in the plant compartment and for the evidence that mitochondria are localized in O2-enriched microenvironments adjacent to intercellular spaces, we propose that steep adenylate gradients may exist between the site of ATP synthesis (and ADP use) in the mitochondria and the extra-mitochondrial sites of ATP use (and ADP production) throughout the large, infected cells.

Kuzma, Monika M.; Winter, Heike; Storer, Paul; Oresnik, Ivan; Atkins, Craig A.; Layzell, David B.

1999-01-01

269

Evaluation of the atmosphere as a source of volatile organic compounds in shallow groundwater  

NASA Astrophysics Data System (ADS)

The atmosphere as a source of volatile organic compounds (VOCs) in shallow groundwater was evaluated over an area in southern New Jersey. Chloroform, methyl tertbutyl ether (MTBE), 1,1,1-trichloroethane, tetrachloroethylene (PCE), and carbon disulfide (not a VOC) were detected frequently at low-level concentrations in a network of 78 shallow wells in the surficial Kirkwood-Cohansey aquifer system. The atmosphere was sampled for these compounds and only MTBE concentrations were high enough to potentially explain frequent detection in shallow groundwater. A mathematical model of reactive transport through the unsaturated zone is presented to explain how variations in unsaturated properties across the study area could explain differences in MTBE concentrations in shallow groundwater given the atmosphere as the source. Even when concentrations of VOCs in groundwater are low compared to regulatory concentration limits, it is critical to know the source. If the VOCs originate from a point source((), concentrations in groundwater could potentially increase over time to levels of concern as groundwater plumes evolve, whereas if the atmosphere is the source, then groundwater concentrations would be expected to remain at low-level concentrations not exceeding those in equilibrium with atmospheric concentrations. This is the first analysis of VOC occurrence in shallow groundwater involving colocated atmosphere data.

Baehr, Arthur L.; Stackelberg, Paul E.; Baker, Ronald J.

1999-01-01

270

Effects of chlorinated solvents on four species of North American amphibians.  

PubMed

Tetrachloroethylene (PCE), a dry cleaning and degreasing solvent, can enter groundwater through accidental leaks or spills, and concentrations as high as 75 mg/L have been reported in Canadian aquifers. Amphibians in wetlands receiving contaminated groundwater may be exposed to PCE and its degradation products, but little information is available on the impacts of these compounds on indigenous amphibian species. Acute (96-h static renewal) exposures to PCE and its major degradation products, trichloroethylene (TCE) and cisand trans-dichloroethylene, were conducted on embryos of four North American amphibian species: wood frogs (Rana sylvatica), green frogs (R. clamitans), American toads (Bufo americanus), and spotted salamanders (Ambystoma maculatum). Subsequently, chronic exposures to PCE and TCE were conducted with the larvae of American toads. Both PCE and TCE were teratogenic to amphibian embryos; median effective concentrations (EC50s) for developmental deformities produced by PCE and TCE exposure for wood frogs and green frogs were 12 and 40 mg/L, respectively. Embryonic survivorship, however, was not compromised at these concentrations. American toads were less sensitive; the EC50 for developmental abnormalities was not attained at the highest test concentrations, 45 and 85 mg/L PCE and TCE, respectively. These results are pertinent in assessing the impact of groundwater pollution on an aquifer-fed wetland. PMID:15346783

McDaniel, T V; Martin, P A; Ross, N; Brown, S; Lesage, S; Pauli, B D

2004-07-01

271

Analytical Modeling of A By-product Transport in Chain Reactions  

NASA Astrophysics Data System (ADS)

Many chemical reactions of contaminants in the subsurface involve complex reaction pathways and networks. As one of those reaction networks, chain-reactions can be found in radionuclide decay, denitrification, biodegradation of chlorinated solvents, etc. For example, this reaction pattern can be illustrated by the biodegrdation of tetrachloroethylene (PCE) and trichloroethylene (TCE). PCE reacts to produce TCE and TCE reacts to form dichloroethylene (DCE). DCE will further reacts to form vinyl chloride (VC) and finally VC reacts to produce thylene (ETH). During the chain reactions, by-products, such as chloride in PCE reaction chain, can be produced in groundwater. For this reason, by-prodcut concentrations in the contaminant plumes are elevated relatively to ambient concentrations. Because of the neutral chemical behavior of some by-products, they can be treated as indicators to identify the sources of contaminants and to estimate reaction rates. Often, a single by-prodcut is produced from multiple steps in a reaction chain. Then, the partial differential equation for by-product mass balance is coupled by multiple reactants. This makes it difficult, if not impossible, to derive analytical solutions using integral transforms. Instead, we conduct singular value decomposition (SVD) analytically and develop a closed-form solution of a by-product transport in multiple chain reactions. In achieving the analytical solution, all reactions are assumed to be first-order and the system is assumed to be homogeneous and isotropic.

Sun, Y.; Lee, K.; Buscheck, T. A.

2003-12-01

272

Modelling of sequential groundwater treatment with zero valent iron and granular activated carbon  

NASA Astrophysics Data System (ADS)

Multiple contaminant mixtures in groundwater may not efficiently be treated by a single technology if contaminants possess rather different properties with respect to sorptivity, solubility, and degradation potential. An obvious choice is to use sequenced units of the generally accepted treatment materials zero valent iron (ZVI) and granular activated carbon (GAC). However, as the results of this modelling study suggest, the required dimensions of both reactor units may strongly differ from those expected on the grounds of a contaminant-specific design. This is revealed by performing an analysis for a broad spectrum of design alternatives through numerical experiments for selected patterns of contaminant mixtures consisting of monochlorobenzene, tetrachloroethylene, trichloroethylene (TCE), cis-1,2-dichloroethylene (cis-DCE), and vinyl chloride (VC). It is shown that efficient treatment can be achieved only if competitive sorption effects in the GAC unit as well as the formation of intermediate products in the ZVI unit are carefully taken into account. Cost-optimal designs turned out to vary extremely depending on the prevailing conditions concerning contaminant concentrations, branching ratios, and unit costs of both reactor materials. Where VC is the critical contaminant, due to high initial concentration or extensive production as an intermediate, two options are cost-effective: an oversized ZVI unit with an oversized GAC unit or a pure GAC reactor.

Bayer, Peter; Finkel, Michael

2005-06-01

273

Trichloroethylene (TCE) adsorption using sustainable organic mulch.  

PubMed

Soluble substrates (electron donors) have been commonly injected into chlorinated solvent contaminated plume to stimulate reductive dechlorination. Recently, different types of organic mulches with economic advantages and sustainable benefits have received much attention as new supporting materials that can provide long term sources of electron donors for chlorinated solvent bioremediation in engineered biowall systems. However, sorption capacities of organic mulches for chlorinated solvents have not been studied yet. In this study, the physiochemical properties of organic mulches (pine, hardwood and cypress mulches) were measured and their adsorption capacity as a potential media was elucidated. Single, binary and quaternary isotherm tests were conducted with trichloroethylene (TCE), tetrachloroethylene (PCE), trans-dichloroethylene (trans-DCE) and cis-dichloroethylene (cis-DCE). Among the three tested mulches, pine mulch showed the highest sorption capacity for the majority of the tested chemicals in single isotherm test. In binary or quaternary isotherm tests, competition among chemicals appears to diminish the differences in Q(e) for tested mulches. However, pine mulch also showed higher adsorption capacity for most chemicals when compared to hardwood and cypress mulches in the two isotherm tests. Based upon physicochemical properties of the three mulches, higher sorption capacity of pine mulch over hardwood and cypress mulches appears to be attributed to a higher organic carbon content and the lower polarity. PMID:20605328

Wei, Zongsu; Seo, Youngwoo

2010-05-02

274

Development of a headspace-solid phase microextraction-gas chromatography method to determine organohalogen contamination in drinking water.  

PubMed

The formation of organohalogen compounds in waters treated by chlorination has drawn increasing scientific attention due to the potentially hazardous health effects of this class of substances. Today, chlorination is the most widely used technology for civil water disinfection. In this study, headspace-solid phase microextraction coupled with GC-electron capture detector was used to determine organohalogen compounds in drinking water sampled from aqueducts and artesian wells in Italy. Experimental parameters, such as sample volume, stirring, salting out, extraction temperature, and extraction time, were evaluated and optimized. The LODs ranged from 1 to 10 ng/L and LOQs from 5 to 50 ng/L. A linear response was confirmed by correlation coefficients ranging from 0.9443 to 0.9999. Quantifiable organohalogen residues were found in 11 water samples, with concentration up to 11.3 +/- 0.5 microg/L for the sum of all trihalomethanes and 0.66 +/- 0.03 microg/L for the sum of trichloroethylene and tetrachloroethylene. These concentrations are lower than the current regulatory limits in Italy. PMID:22468363

Mariani, Maurizio Boccacci; Giannetti, Vanessa; Testani, Elena; D'Aiuto, Virginia

275

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

PubMed

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

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

2010-09-16

276

Steam reforming of DOE complex waste simulants  

SciTech Connect

Sandia National Laboratories has worked with Synthetica Technologies and Manufacturing and Technology Conversion International (MTCl) to demonstrate the applicability of their commercial steam reforming technologies for treating DOE low-level mixed wastes. Previously, Synthetica successfully demonstrated destruction of a Sandia formulated lab trash simulant. During November 1994 Synthetica did not adequately process the aqueous halogenated organic liquid mixed waste simulant (MWTP-2110) formulated by the DOE Mixed Waste Integrated Program (MWIP). Testing at MTCl is ongoing and initial results appear to be favorable. Approximately 200 lbs each of the MWIP aqueous halogenated organic liquids (MWTP-2110), and absorbed aqueous and organic liquids (MWTP-3113/3114) simulants have been processed. At 1650{degree}F, destruction efficiencies of greater than 99% were obtained for tetrachloroethylene, toluene, and 1,2 dichlorobenzene. Product cases consisted primarily of H{sub 2}, C0{sub 2}, CO, and CH{sub 4} and had higher heating values of up to 355 BTU/SCF. Conclusions concerning the suitability of the MTCI process for treating DOE mixed wastes will be drawn upon the completion of testing.

Miller, J.E.; Kuehne, P.B.

1995-03-01

277

Background concentrations of 18 air toxics for North America.  

PubMed

The U.S. Clean Air Act identifies 188 hazardous air pollutants (HAPs), or "air toxics," associated with adverse human health effects. Of these air toxics, 18 were targeted as the most important in a 10-City Pilot Study conducted in 2001 and 2002 as part of the National Air Toxics Trend Sites Program. In the present analysis, measurements available from monitoring networks in North America were used to estimate boundary layer background concentrations and trends of these 18 HAPs. The background concentrations reported in this study are as much as 85% lower than those reported in recent studies of HAP concentrations. Background concentrations of some volatile organic compounds were analyzed for trends at the 95% confidence level; only carbon tetrachloride (CCI4) and tetrachloroethylene decreased significantly in recent years. Remote background concentrations were compared with the one-in-a-million (i.e., 10(6)) cancer benchmarks to determine the possible causes of health risk in rural and remote areas; benzene, chloroform, formaldehyde, and chromium (Cr) fine particulate were higher than cancer benchmark values. In addition, remote background concentrations were found to contribute between 5% and 99% of median urban concentrations. PMID:16499141

McCarthy, Michael C; Hafner, Hilary R; Montzka, Stephen A

2006-01-01

278

Health assessment for Welsh Road/Barkman Landfill, Honey Brook, Chester County, Pennsylvania, Region 3. CERCLIS No. PAD980829527. Preliminary report  

SciTech Connect

The Welsh Road/Barkman Landfill site in Honey Brook, Pennsylvania was an unpermitted residential and commercial refuse disposal facility that operated from 1963 to sometime in the 1980s. After 1977, the landfill continued to operate in defiance of legal action to support a closure plan. Various investigations conducted in the 1980s revealed that industrial and hazardous waste had been accepted by the site. The environmental contamination on-site consists of copper, lead, 1,2-dichloropropane, toluene, chloroform and methylene chloride in drummed wastes; and mercury, toluene, dichlorofluoromethane, methylene chloride, trichlorofluoromethane, 5-methyl-2-hexanone, trichloroethylene, 1,2-dichloroethane, and 1,3,5-cycloheptatriene in groundwater. One time sampling indicated the presence of volatile compounds in air (hydrogen chloride and chloroform). The environmental contamination off-site consists of cadmium in sediment; and chloromethane, chloroform, xylenes, dichlorofluoromethane, 1,1-dichloroethane, tetrachloroethylene, p-cresol, toluene, methyl isobutyl ketone, di-n-butyl phthalate, lead, mercury, and zinc in residential well water. The site is considered to be of potential public health concern because of the risk to human health caused by the possibility of exposure to hazardous substances via contaminated groundwater, surface water, soil, sediment, and airborne gases, vapors, and particulate.

Not Available

1988-12-02

279

Chlorinated organic compounds in ground water at Roosevelt Field, Nassau County, Long Island, New York  

USGS Publications Warehouse

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)

Eckhardt, D. A.; Pearsall, K. A.

1989-01-01

280

Testing of stack-unit/aquifer sensitivity analysis using contaminant plume distribution in the subsurface of Savannah River Site, South Carolina, USA  

USGS Publications Warehouse

Published information on the correlation and field-testing of the technique of stack-unit/aquifer sensitivity mapping with documented subsurface contaminant plumes is rare. The inherent characteristic of stack-unit mapping, which makes it a superior technique to other analyses that amalgamate data, is the ability to deconstruct the sensitivity analysis on a unit-by-unit basis. An aquifer sensitivity map, delineating the relative sensitivity of the Crouch Branch aquifer of the Administrative/Manufacturing Area (A/M) at the Savannah River Site (SRS) in South Carolina, USA, incorporates six hydrostratigraphic units, surface soil units, and relevant hydrologic data. When this sensitivity map is compared with the distribution of the contaminant tetrachloroethylene (PCE), PCE is present within the Crouch Branch aquifer within an area classified as highly sensitive, even though the PCE was primarily released on the ground surface within areas classified with low aquifer sensitivity. This phenomenon is explained through analysis of the aquifer sensitivity map, the groundwater potentiometric surface maps, and the plume distributions within the area on a unit-by- unit basis. The results of this correlation show how the paths of the PCE plume are influenced by both the geology and the groundwater flow. ?? Springer-Verlag 2006.

Rine, J. M.; Shafer, J. M.; Covington, E.; Berg, R. C.

2006-01-01

281

Separation of volatile organic compounds from dry and humidified nitrogen using polyurethane membranes  

SciTech Connect

Homogeneous polyurethane membranes, containing ether or ester soft segments, were examined for the vapor-phase separation of tetrachloroethylene, carbon tetrachloride, benzene, toluene, p-xylene, hexane, and benzene/toluene/xylene mixtures from nitrogen. Both equilibrium sorption/desorption and organic/N{sub 2} separation experiments were carried out. The membranes performed best with aromatic and chlorine-containing organic compounds, with organic/dry N{sub 2} selectivities ranging from 30 to 210 and pressure-normalized permeabilities as high as 1.25 {times} 10{sup {minus}3} cm{sup 3} (STP)/(cm{sup 2} s cmHg) for saturated organic feeds at 23 C and a downstream pressure of 0.005--0.01 atm. Organic/N{sub 2} selectivities and organic permeabilities were generally higher than those reported in the literature for poly(dimethylsiloxane) and aromatic polyimide membranes. Organic permeabilities in the ether soft segment polyurethane membranes were greater than those measured in the polyester films, due to higher organic solubility coefficients (more polymer swelling). The greater swelling of the polyether membranes increased the nitrogen permeabilities and lowered the organic/N{sub 2} selectivities relative to those for polyester membranes. Water permeabilities in both types of polyurethane membranes were low and independent of the organic feed component. The presence of water vapor in the feed (up to 1.2 vol %) had no effect on transmembrane organic fluxes.

Ponangi, R.P.; Pintauro, P.N. [Tulane Univ., New Orleans, LA (United States). Dept. of Chemical Engineering

1996-08-01

282

Inspection and monitoring plan, contaminated groundwater seeps 317/319/ENE Area, Argonne National Laboratory  

SciTech Connect

During the course of completing the Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI) in the 317/319/East-Northeast (ENE) Area of Argonne National Laboratory-East (ANL-E), groundwater was discovered moving to the surface through a series of groundwater seeps. The seeps are located in a ravine approximately 600 ft south of the ANL-E fence line in Waterfall Glen Forest Preserve. Samples of the seep water were collected and analyzed for selected parameters. Two of the five seeps sampled were found to contain detectable levels of organic contaminants. Three chemical species were identified: chloroform (14--25 {micro}g/L), carbon tetrachloride (56--340 {micro}g/L), and tetrachloroethylene (3--6 {micro}g/L). The other seeps did not contain detectable levels of volatile organics. The nature of the contaminants in the seeps will also be monitored on a regular basis. Samples of surface water flowing through the bottom of the ravine and groundwater emanating from the seeps will be collected and analyzed for chemical and radioactive constituents. The results of the routine sampling will be compared with the concentrations used in the risk assessment. If the concentrations exceed those used in the risk assessment, the risk calculations will be revised by using the higher numbers. This revised analysis will determine if additional actions are warranted.

NONE

1996-10-11

283

Influence of sulfur oxyanions on reductive dehalogenation activities in Desulfomonile tiedjei.  

PubMed Central

The inhibition of aryl reductive dehalogenation reactions by sulfur oxyanions has been demonstrated in environmental samples, dehalogenating enrichments, and the sulfate-reducing bacterium Desulfomonile tiedjei; however, this phenomenon is not well understood. We examined the effects of sulfate, sulfite, and thiosulfate on reductive dehalogenation in the model microorganism D. tiedjei and found separate mechanisms of inhibition due to these oxyanions under growth versus nongrowth conditions. Dehalogenation activity was greatly reduced in extracts of cells grown in the presence of both 3-chlorobenzoate, the substrate or inducer for the aryl dehalogenation activity, and either sulfate, sulfite, or thiosulfate, indicating that sulfur oxyanions repress the requisite enzymes. In extracts of fully induced cells, thiosulfate and sulfite, but not sulfate, were potent inhibitors of aryl dehalogenation activity even in membrane fractions lacking the cytoplasmically located sulfur oxyanion reductase. These results suggest that under growth conditions, sulfur oxyanions serve as preferred electron acceptors and negatively influence dehalogenation activity in D. tiedjei by regulating the amount of active aryl dehalogenase in cells. Additionally, in vitro inhibition by sulfur oxyanions is due to the interaction of the reactive species with enzymes involved in dehalogenation and need not involve competition between two respiratory processes for reducing equivalents. Sulfur oxyanions also inhibited tetrachloroethylene dehalogenation by the same mechanisms, further indicating that chloroethylenes are fortuitously dehalogenated by the aryl dehalogenase. The commonly observed inhibition of reductive dehalogenation reactions under sulfate-reducing conditions may be due to similar regulation mechanisms in other dehalogenating microorganisms that contain multiple respiratory activities.

Townsend, G T; Suflita, J M

1997-01-01

284

Influence of sulfur oxyanions on reductive dehalogenation activities in Desulfomonile tiedjei.  

PubMed

The inhibition of aryl reductive dehalogenation reactions by sulfur oxyanions has been demonstrated in environmental samples, dehalogenating enrichments, and the sulfate-reducing bacterium Desulfomonile tiedjei; however, this phenomenon is not well understood. We examined the effects of sulfate, sulfite, and thiosulfate on reductive dehalogenation in the model microorganism D. tiedjei and found separate mechanisms of inhibition due to these oxyanions under growth versus nongrowth conditions. Dehalogenation activity was greatly reduced in extracts of cells grown in the presence of both 3-chlorobenzoate, the substrate or inducer for the aryl dehalogenation activity, and either sulfate, sulfite, or thiosulfate, indicating that sulfur oxyanions repress the requisite enzymes. In extracts of fully induced cells, thiosulfate and sulfite, but not sulfate, were potent inhibitors of aryl dehalogenation activity even in membrane fractions lacking the cytoplasmically located sulfur oxyanion reductase. These results suggest that under growth conditions, sulfur oxyanions serve as preferred electron acceptors and negatively influence dehalogenation activity in D. tiedjei by regulating the amount of active aryl dehalogenase in cells. Additionally, in vitro inhibition by sulfur oxyanions is due to the interaction of the reactive species with enzymes involved in dehalogenation and need not involve competition between two respiratory processes for reducing equivalents. Sulfur oxyanions also inhibited tetrachloroethylene dehalogenation by the same mechanisms, further indicating that chloroethylenes are fortuitously dehalogenated by the aryl dehalogenase. The commonly observed inhibition of reductive dehalogenation reactions under sulfate-reducing conditions may be due to similar regulation mechanisms in other dehalogenating microorganisms that contain multiple respiratory activities. PMID:9293011

Townsend, G T; Suflita, J M

1997-09-01

285

Synergistic and antagonistic effects on genotoxicity of chemicals commonly found in hazardous waste sites  

SciTech Connect

Synergistic and antagonistic effects on genotoxicity of mixtures of four chemicals; i.e., lead tetraacetate (LTA), arsenic trioxide (ATO), dieldrin (DED), and tetrachloroethylene (TCE), were evaluated by the Tradescantia-micronucleus (Trad-MCN) assay. The chemicals were mixed in ratios of 1:1, 1:2 and 2:1 for mixtures of two chemicals and 1:1:1 each for three chemicals. The concentration of stock solution of these chemicals was around the minimum effective dose (MED) or below the MED for these chemicals as reported by Sandhu et al. (1989). Treatments were applied to plant cuttings by hydroponic uptake of the mixed solutions through the stems of the plant for 30 h followed by fixation of the flower buds in aceto-alcohol (1:3 ratio) without a recovery period. Microslides were prepared for scoring MCN frequencies. Results of two series of repeated experiments indicated that all mixtures of LTA/ATO exhibited antagonistic effects. On the other hand, all mixtures of TCE and DED exhibited synergistic effect. These data indicate that for evaluating biological hazards at chemical waste sites, it is prudent to evaluate the genotoxicity of complex chemical mixtures as these exist in nature because the biological effects based on evaluating individual chemicals may not be true predictors of the interactive effects of the pollutants.

Ma, T.H.; Sandhu, S.S.; Peng, Y.; Chen, T.D.; Kim, T.W.

1992-01-01

286

DESORPTION BEHAVIOR OF TRICHLOROETHENE AND TETRACHLOROETHENE IN U.S. DEPARTMENT OF ENERGY SAVANNAH RIVER SITE UNCONFINED AQUIFER SEDIMENTS  

SciTech Connect

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.

Vangelas, K; Robert G. Riley, R; James E. Szecsody, J; A. V. Mitroshkov, A; C. F. Brown, C; Brian02 Looney, B

2007-01-10

287

Use of sonication for in-well softening of semivolatile organic compounds. 1998 annual progress report  

SciTech Connect

'This project investigates the in-situ degradation of semivolatile organic compounds (SVOCs) and volatile organic compounds (VOCs) using in-well sonication, in-well vapor stripping, and biodegradation. The project has the primary objectives of developing this integrated system for efficient and economical removal and degradation of SVOCs and VOCs from groundwater. The project has as its goal the partial degradation (softening) of the more recalcitrant organic compounds in order to convert them into compounds that are more amenable to both air sparging and biological treatment. By performing the softening in-well, the treated organics can be reinjected and percolated through the subsurface, thereby enhancing biodegradation by generating organics that are more easily biodegraded. This report summarizes work after nearly 2 years of a 3-year project. Argonne National Laboratory is developing a new technology that combines in-well sonication, in-well vapor stripping, and in-situ biodegradation for removal of SVOCs and VOCs from solution. Bench-scale batch experiments have been performed investigating the separate treatment systems involving stripping and sonication of halogenated organics in groundwater, along with the combined sonication/stripping system. Organic contaminants studied include: trichloroethylene (TCE), carbon tetrachloride (CCl4 ), tetrachloroethylene (PCE), trichloroethane (TCA), and ethylene dibromide (EDB). Initial organic concentrations range from {approximately}10 to {approximately}100 mg/L. Results of the sonication and vapor stripping experiments are available upon request.'

Peters, R.W.; Manning, J.F. [Argonne National Lab., IL (US); Hoffmann, M.R. [California Inst. of Tech., Pasadena, CA (US); Gorelick, S. [Stanford Univ., CA (US)

1998-06-01

288

Use of Sonification for In-Well Softening of Semivolatile Organic Compounds  

SciTech Connect

This study examined an integrated sonication/vapor stripping system's ability to remove/destroy chlorinated organics from groundwater. Chlorinated solvents studied included carbon tetrachloride, trichloroethylene, trichloroethane and tetrachloroethylene. Contaminant concentrations ranged from {approx}1 to {approx}100 mg/L. The sonicator had an ultrasonic frequency of 20 kHz; applied power intensities were 12.3-, 25.3- and 35.8-W/cm2. Batch reactions were operated for up to 10 minutes treatment time, with samples drawn for GC analysis every 2 minutes. Batch experimental results were obtained using sonication, vapor stripping and combined sonication/vapor stripping. For the chlorinated solvents, the first order rate constants were in the range of 0.02 to 0.06 min-1, 0.23 to 0.53 min-1 and 0.34 to 0.90 min-1 for sonication, vapor stripping and combined sonication/vapor stripping. For the chlorinated organics (treatment time {approx}10 min.), the fraction remaining after sonication and vapor stripping ranged from 62% to 82%, while less than 3% remained from the combined sonication/vapor stripping system.

Peters, Robert W.; Manning, John L.; Ayyiliz, Onder; Wilkey, Michael L.

2003-03-26

289

Sanitary landfill groundwater monitoring report. Fourth quarter 1996 and 1996 summary  

SciTech Connect

A maximum of eighty-nine wells of the LFW series monitor groundwater quality in the Steed Pond Aquifer (Water Table) beneath the Sanitary Landfill at the Savannah River Site (SRS). These wells are sampled quarterly to comply with the South Carolina Department of Health and Environmental Control Domestic Waste Permit DWP-087A and as part of the SRS Groundwater Monitoring Program. Dichloromethane, a common laboratory contaminant, and chloroethene (vinyl chloride) were the most widespread constituents exceeding standards during 1996. Benzene, trichloroethylene, 1,4-dichlorobenzene, 1,1-dichloroethylene, lead (total recoverable), gross alpha, mercury (total recoverable), tetrachloroethylene, fluoride, thallium, radium-226, radium-228, and tritium also exceeded standards in one or more wells. The groundwater flow direction in the Steed Pond Aquifer (Water Table) beneath the Sanitary Landfill was to the southeast (universal transverse Mercator coordinates). The flow rate in this unit was approximately 141 ft/year during first quarter 1996 and 132 ft/year during fourth quarter 1996

NONE

1997-02-01

290

Analysis of nitrate and volatile organic compound data for ground water in the Great Salt Lake Basins, Utah, Idaho, and Wyoming, 1980-98, National Water-Quality Assessment Program  

USGS Publications Warehouse

In 1995, ground water was the source of drinking water to about 52 percent of the population served by public drinking water systems in the Great Salt Lake Basins study unit, which includes parts of Utah, Idaho, and Wyoming. Existing nitrate and volatile organic compound data for ground water collected in the study unit were compiled and summarized as part of the National Water-Quality Assessment Program?s objective to describe water-quality conditions in the Nation?s aquifers. Prerequisites for the inclusion of nitrate and volatile organic compound data into this retrospective analysis are that the data set is available in electronic form, the data were collected during 1980-98, the data set is somewhat regional in coverage, and the locations of the sampled sites are known. Ground-water data stored in the U.S. Geological Survey?s National Water Information Systemand the Idaho and Utah Public DrinkingWater Systems databases were reviewed. Only the most recent analysis was included in the data sets if more than one analysis was available for a site. The National Water Information System data set contained nitrate analyses for water from 480 wells. The median concentration of nitratewas 1.30 milligrams per liter for the 388 values above minimum reporting limits. The maximum contaminant level for nitrate as established by the U.S. Environmental Protection Agency was exceeded in water from 10 of the 200 wells less than or equal to 150 feet deep and in water from3 of 280 wells greater than 150 feet deep. The Public Drinking Water Systems data set contained nitrate analyses for water from 587 wells. The median concentration of nitrate was 1.12 milligrams per liter for the 548 values above minimum reporting limits. The maximum contaminant level for nitrate was exceeded at 1 site and 22 sites had concentrations equal to or greater than 5 milligrams per liter. The types of land use surrounding a well and the well depth were related to measured nitrate concentrations in the sampled ground water. Overall, water sampled from wells in rangeland areas had a lowermedianmeasured nitrate concentration (0.76 milligrams per liter) than water from areas with an agricultural or urban/residential land use (1.41 and 1.20 milligrams per liter, respectively). In the NationalWater Information System data set, the median measured nitrate concentration in water from urban/residential areas varied from 1.00 milligrams per liter for wells greater than 150 feet deep to 1.84 milligrams per liter for wells less than or equal to 150 feet deep. The Public DrinkingWater Systems and the National Water Information System data sets contained analyses for most of the State and Federally regulated volatile organic compounds in water from about 368 and 74 wells, respectively. Fifteen different volatile organic compounds were detected at least once in ground water sampled from the Great Salt Lake Basins study unit. Water from 21 wells contained at least 1 volatile organiccompound at detectable concentrations. About 68 percent of the volatile organic compounds detected were in water sampled from wells in Salt Lake County, Utah. Tetrachloroethylene was the most commonly detected volatile organic compound in ground water sampled from the study unit, present in 8 out of 442 samples. Maximum contaminant levels for tetrachloroethylene and 1,1-dichloroethylene as established by the U.S. Environmental Protection Agency were exceeded in water from one well each.

Thiros, Susan A.

2000-01-01

291

The Behavior of an Industrial Chlorinated Solvent DNAPL in the Presence of an Alcohol Cosolvent  

NASA Astrophysics Data System (ADS)

Chlorinated dense non-aqueous phase liquids (DNAPLs), such as tetrachloroethylene (PCE), pose a significant challenge to groundwater cleanup. Many chlorinated solvents were used first in industrial and commercial cleaning processes prior to release into the environment. As a result, these DNAPLs can contain greases, oils, and even PCBs. These trace contaminants can have very different properties compared to the chlorinated solvents that make up the bulk of the DNAPL. The use of steam, surfactants, and cosolvents are promising techniques for accelerating the removal of DNAPLs from porous media. Many of these techniques are based on laboratory investigations that utilized reagent grade DNAPL chemicals. A major assumption in DNAPL remediation design and modeling is that minor constituents do not have an effect. However, the role of trace contaminants is not well understood. The presence of trace contaminants (absent from reagent grade chemicals) may reduce the ability of remediation techniques to effectively remove all of the contaminants that pose a risk to human health and the environment. This preliminary research investigates the role of trace contaminants on the behavior of an industrial PCE DNAPL in a porous media in the presence of cosolvents. The DNAPL used in this study was first used as part of an industrial degreasing process, then discharged into the subsurface environment, where it remained for more than 10 years. This study includes the determination of the equilibrium phase behavior and preliminary characterization of the trace contaminants. The ternary system of water/n-propanol/DNAPL was used to compare the behavior of the used industrial PCE DNAPL with a reagent grade PCE DNAPL. Behavior of the bulk DNAPL is similar for both the industrial and reagent grade PCE DNAPLs. The distribution of trace contaminants varies and even formed a third phase in some ternary phase mixtures. The isolation of the trace contaminants has important implications regarding the use of cosolvent flooding for the remediation of used industrial PCE DNAPLs.

Myers, J. L.; Lee, C. M.; Falta, R. W.

2001-12-01

292

Determination of volatile organic hydrocarbons in water samples by solid-phase dynamic extraction.  

PubMed

In the present study a headspace solid-phase dynamic extraction method coupled to gas chromatography-mass spectrometry (HS-SPDE-GC/MS) for the trace determination of volatile halogenated hydrocarbons and benzene from groundwater samples was developed and evaluated. As target compounds, benzene as well as 11 chlorinated and brominated hydrocarbons (vinyl chloride, dichloromethane, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, carbon tetrachloride, chloroform, trichloroethylene, tetrachloroethylene, bromoform) of environmental and toxicological concern were included in this study. The analytes were extracted using a SPDE needle device, coated with a poly(dimethylsiloxane) with 10% embedded activated carbon phase (50-microm film thickness and 56-mm film length) and were analyzed by GC/MS in full-scan mode. Parameters that affect the extraction yield such as extraction and desorption temperature, salting-out, extraction and desorption flow rate, extraction volume and desorption volume, the number of extraction cycles, and the pre-desorption time have been evaluated and optimized. The linearity of the HS-SPDE-GC/MS method was established over several orders of magnitude. Method detection limits (MDLs) for the compounds investigated ranged between 12 ng/L for cis-dichloroethylene and trans-dichloroethylene and 870 ng/L for vinyl chloride. The method was thoroughly validated, and the precision at two concentration levels (0.1 mg/L and a concentration 5 times above the MDL) was between 3.1 and 16% for the analytes investigated. SPDE provides high sensitivity, short sample preparation and extraction times and a high sample throughput because of full automation. Finally, the applicability to real environmental samples is shown exemplarily for various groundwater samples from a former waste-oil recycling facility. Groundwater from the site showed a complex contamination with chlorinated volatile organic compounds and aromatic hydrocarbons. PMID:17242891

Jochmann, Maik A; Yuan, Xue; Schmidt, Torsten C

2007-01-23

293

Exposure to carcinogens for defined job categories in Norway's offshore petroleum industry, 1970 to 2005  

PubMed Central

Objectives To identify and describe the exposure to selected known and suspected carcinogenic agents, mixtures and exposure circumstances for defined job categories in Norway's offshore petroleum industry from 1970 to 2005, in order to provide exposure information for a planned cohort study on cancer. Methods Background information on possible exposure was obtained through company visits, including interviewing key personnel (n?=?83) and collecting monitoring reports (n?=?118) and other relevant documents (n?=?329). On the basis of a previous questionnaire administered to present and former offshore employees in 1998, 27 job categories were defined. Results This study indicated possible exposure to 18 known and suspected carcinogenic agents, mixtures or exposure circumstances. Monitoring reports were obtained on seven agents (benzene, mineral oil mist and vapour, respirable and total dust, asbestos fibres, refractory ceramic fibres, formaldehyde and tetrachloroethylene). The mean exposure level of 367 personal samples of benzene was 0.037?ppm (range: less than the limit of detection to 2.6?ppm). Asbestos fibres were detected (0.03?fibres/cm3) when asbestos?containing brake bands were used in drilling draw work in 1988. Personal samples of formaldehyde in the process area ranged from 0.06 to 0.29?mg/m3. Descriptions of products containing known and suspected carcinogens, exposure sources and processes were extracted from the collected documentation and the interviews of key personnel. Conclusions This study described exposure to 18 known and suspected carcinogenic agents, mixtures and exposure circumstances for 27 job categories in Norway's offshore petroleum industry. For a planned cohort study on cancer, quantitative estimates of exposure to benzene, and mineral oil mist and vapour might be developed. For the other agents, information in the present study can be used for further assessment of exposure, for instance, by expert judgement. More systematic exposure surveillance is needed in this industry. For future studies, new monitoring programmes need to be implemented.

Steinsvag, Kjersti; Bratveit, Magne; Moen, Bente E

2007-01-01

294

Rush-hour aromatic and chlorinated hydrocarbons in selected subway stations of Shanghai, China.  

PubMed

Air samples were collected simultaneously at platform, mezzanine and outdoor in five typical stations of subway system in Shanghai, China using stainless steel canisters and analyzed by gas chromatography-mass selective detector (GC-MSD) after cryogenic preconcentration. Benzene, toluene, ethylbenzene and xylenes (BTEX) at the platforms and mezzanines inside the stations averaged (10.3 +/- 2.1), (38.7 +/- 9.0), (19.4 +/- 10.1) and (30.0 +/- 11.1) microg/m3, respectively; while trichloroethylene (TrCE), tetrachloroethylene (TeCE) and para-dichlorobenzene (pDCB), vinyl chloride and carbon tetrachloride were the most abundant chlorinated hydrocarbons inside the stations with average levels of (3.6 +/- 1.3), (1.3 +/- 0.5), (4.1 +/- 1.1), (2.2 +/- 1.1) and (1.2 +/- 0.3) microg/m3, respectively. Mean levels of major aromatic and chlorinated hydrocarbons were higher indoor (platforms and mezzanines) than outdoor with average indoor/outdoor (I/O) ratios of 1.1-9.5, whereas no significant indoor/outdoor differences were found except for benzene and TrCE. The highly significant mutual correlations (p < 0.01) for BTEX between indoor and outdoor and their significant correlation (p < 0.05) with methyl tert-butyl ether (MTBE), a marker of traffic-related emission without other indoor and outdoor sources, indicated that BTEX were introduced into the subway stations from indoor/outdoor air exchange and traffic emission should be their dominant source. TrCE and pDCB were mainly from indoor emission and TeCE might have both indoor emission sources and contribution from outdoor air, especially in the mezzanines. PMID:22783624

Zhang, Yanli; Li, Chunlei; Wang, Xinming; Guo, Hai; Feng, Yanli; Chen, Jianmin

2012-01-01

295

Perchloroethylene-contaminated drinking water and the risk of breast cancer: additional results from Cape Cod, Massachusetts, USA.  

PubMed Central

In 1998 we published the results of a study suggesting an association between breast cancer and perchloroethylene (PCE; also called tetrachloroethylene) exposure from public drinking water. The present case-control study was undertaken to evaluate this association further. The cases were composed of female residents of eight towns in the Cape Cod region of Massachusetts who had been diagnosed with breast cancer from 1987 through 1993 (n = 672). Controls were composed of demographically similar women from the same towns (n = 616). Women were exposed to PCE when it leached from the vinyl lining of water distribution pipes from the late 1960s through the early 1980s. A relative delivered dose of PCE that entered a home was estimated using an algorithm that took into account residential history, water flow, and pipe characteristics. Small to moderate elevations in risk were seen among women whose exposure levels were above the 75th and 90th percentiles when 0-15 years of latency were considered (adjusted odds ratios, 1.5-1.9 for > 75th percentile, 1.3-2.8 for > 90th percentile). When data from the present and prior studies were combined, small to moderate increases in risk were also seen among women whose exposure levels were above the 75th and 90th percentiles when 0-15 years of latency were considered (adjusted odds ratios, 1.6-1.9 for > 75th percentile, 1.3-1.9 for > 90th percentile). The results of the present study confirm those of the previous one and suggest that women with the highest PCE exposure levels have a small to moderate increased risk of breast cancer.

Aschengrau, Ann; Rogers, Sarah; Ozonoff, David

2003-01-01

296

High-rate continuous biodegradation of concentrated chlorinated aliphatics by a durable enrichment of methanogenic origin under carrier-dependent conditions.  

PubMed

The simultaneous biodegradation of toxic compounds in mixtures is a major current concern. To bioremediate a toxic mixture, we designed a strategy combining an ad-sorbent carrier with an ecological and nutritional system which allowed work close to heavily polluted conditions in nature. Starting from a methanogenic community, we developed a microbial consortium acclimated to a mixture of about 30 chlorinated aliphatics in a fixed-film stationary-bed bioreactor. Prior to the establishment of a durable period of dechlorination, an interval of progressive dechlorination of the toxic mixture was observed during which the excess of the toxic compounds was stored on the carrier. The latter, consisting of activated carbon in a polyurethane foam, allowed us to work at concentrations far above the solubility of the toxic compounds (apparent concentrations of about 10 g/L). The complete disappearance of hexachloroethane as well as its lower homologues, penta-, tetra-, and trichloroethane, present in the toxic mixture, was observed. Additionally, octachlorocyclopentene, carbon tetrachloride, trichloro-ethylene, tetrachloroethylene, and hexachloro-1,3-butadiene also completely disappeared. For the four latter compounds, from mass balances in the bioreactor, degradation rates around 10 mumol/L per day were determined with total dechlorination. The enrichment culture thus developed exhibited high degradation performances similar to those reported in the literature for pure or enriched anaerobic microbial cultures in contact with a single toxic compound. The results demonstrate the possibility of concurrent high-rate degradation of several highly chlorinated toxic compounds, under conditions approximating field situations.(c) 1995 John Wiley & Sons, Inc. PMID:18623405

Boucquey, J B; Renard, P; Amerlynck, P; Filho, P M; Agathos, S N; Naveau, H; Nyns, E J

1995-08-01

297

Application of a new vertical profiling tool (ESASS) for sampling groundwater quality during hollow-stem auger drilling  

USGS Publications Warehouse

A new tool called ESASS (Enhanced Screen Auger Sampling System) was developed by the U.S. Geological Survey. The use of ESASS, because of its unique U.S. patent design (U.S. patent no. 7,631,705 B1), allows for the collection of representative, depth-specific groundwater samples (vertical profiling) in a quick and efficient manner using a 0.305-m long screen auger during hollow-stem auger drilling. With ESASS, the water column in the flights above the screen auger is separated from the water in the screen auger by a specially designed removable plug and collar. The tool fits inside an auger of standard inner diameter (82.55 mm). The novel design of the system constituted by the plug, collar, and A-rod allows the plug to be retrieved using conventional drilling A-rods. After retrieval, standard-diameter (50.8 mm) observation wells can be installed within the hollow-stem augers. Testing of ESASS was conducted at one waste-disposal site with tetrachloroethylene (PCE) contamination and at two reference sites with no known waste-disposal history. All three sites have similar geology and are underlain by glacial, stratified-drift deposits. For the applications tested, ESASS proved to be a useful tool in vertical profiling of groundwater quality. At the waste site, PCE concentrations measured with ESASS profiling at several depths were comparable (relative percent difference <25%) to PCE concentrations sampled from wells. Vertical profiling with ESASS at the reference sites illustrated the vertical resolution achievable in the profile system; shallow groundwater quality varied by a factor of five in concentration of some constituents (nitrate and nitrite) over short (0.61 m) distances.

Harte, Philip T.; Flanagan, Sarah M.

2011-01-01

298

Experimental Results on the Destruction of PCE using a Photo-Chemical Remediation Reactor  

NASA Astrophysics Data System (ADS)

A vapor-phase tetrachloroethylene (PCE) destruction experiment using a newly constructed photo-chemical remediation (PCR) reactor is performed. One of the applications for the PCR reactor is subsurface remediation of volatile organic compounds (VOCs). Ultraviolet (UV) light, when emitted at an effective absorption frequency (primary wavelengths of 185 and 254 nm), cleaves a VOC's carbon-chlorine bond thus reducing harmful contaminants to harmless products. The PCR reactor consists of a stainless steel tubular vessel with internal dimensions 0.32 m in diameter and 1.05 m in length. Sixteen Suprasil glass sleeves (Heraeus Inc.) with external dimensions of 25 mm in diameter and 1.1 m in length are inserted along the length of the reactor. The Suprasil sleeves are positioned in a geometrical pattern to provide maximum UV exposure. An amalgam UV lamp (Heraeus Inc. NIQ 200/110) is placed inside every Suprasil sleeve. Each UV lamp has its own igniter and ballast for versatile power control. The Suprasil sleeves provide barrier protection between the UV lamps and the vapor-phase contaminant, and at the same time allow transmission of UV light to the interior of the PCR reactor. A gas heater is installed to increase the influent vapor-phase temperature and the PCR reactor is insulated to minimize heat loss. However, the PCE destruction experiment is presently being performed without the aid of the gas heater. During the experiment, the PCR reactor temperature reached in excess of 200 degrees Celsius from heat generated from the UV lamps. Vapor-phase samples are collected at the influent and effluent reactor sampling ports prior and after UV lamp ignitions. Preliminary results show good PCE destruction efficiency for the range of influent PCE concentrations considered in this study.

Lee, J. J.; Lee, K. Y.; Stencel, J. R.; Khinast, J.

2001-12-01

299

A Modified Light Transmission Visualization Method for DNAPL Saturation Measurements in 2-D Models  

NASA Astrophysics Data System (ADS)

In this research, a light transmission visualization (LTV) method was used to quantify dense non-aqueous phase liquids (DNAPL) saturation in two-dimensional (2-D), two fluid phase systems. The method is an expansion of earlier LTV methods and takes into account both absorption and refraction light theories. Based on this method, DNAPL and water saturations can rapidly be obtained point wise across sand-packed 2-D flow chambers without the need to develop a calibration curve. The method was applied to measure, for the first time, undyed DNAPL saturation in small 2-D chambers. Known amounts of DNAPL, modeled by tetrachloroethylene (PCE), were added to the chamber and these amounts were compared to results obtained by this LTV method. Strong correlation existed between results obtained based on this method and the known PCE amounts with an R2 value of 0.993. Similar experiments conducted using dyed PCE showed a stronger correlation between results obtained by this LTV method and the known amounts of dyed PCE added to the chamber with an R2 value of 0.999. The method was also used to measure dyed PCE saturation in a large 2-D model following sparging experiments. Results obtained from image analyses following each sparging event were compared to results obtained by two independent techniques, namely gas chromatography-mass spectrometry (GC/MS) analyses and carbon column extraction. There was a good agreement between the results obtained by this LTV method and those obtained by the two independent techniques when experiments were carried out under stable light source conditions, and errors in mass balance were minor. The method presented here can be expanded to measure fluid contents in three fluid phase systems and provide a non-destructive, non-intrusive tool to investigate changes in DNAPL architecture and flow characteristics in laboratory experiments. Disclaimer This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.

Bob, M. M.; Brooks, M. C.; Mravik, S. C.; Wood, L.

2007-12-01

300

Concentrations, loads and yields of selected water-quality constituents during low flow and storm runoff from three watersheds at Fort Leavenworth, Kansas, May 1994 through September 1996  

USGS Publications Warehouse

A study of the effects of storm runoff from urban areas on water quality at Fort Leavenworth, Kansas, was conducted from May 1994 through September 1996. The purpose of this report is to present information to assess the current (1994-96) conditions and possible methods for anticipating future water-quality effects from storm runoff and changes in land use. Three sampling sites were established to monitor streamflow and water quality from three watersheds draining the study area. Streamflow was monitored continuously, and water-quality samples were collected during low-flow (12 samples) and storm-runoff (21 samples) conditions to determine mean annual constituent loads. Constituent concentrations for the most part were smallest during low flow with the exception of major ions, dissolved solids, and some nutrients. Concentrations of suspended solids and total recoverable metals at all three sites were much larger in storm-runoff samples than in low-flow samples--typically an order of magnitude larger than low-flow concentrations. Mean low-flow nutrient concentrations were either larger than or smaller than storm-runoff concentrations depending on the watershed. Total chloroform and total tetrachloroethylene were the only two volatile organic compounds detected, and acid-base/neutral organic compounds were not detected in any of the samples collected. Eight pesticides were detected in low-flow samples, and 15 pesticides were detected in storm-runoff samples. The only mean concentrations of the selected constituents in this study that exceeded either the U.S. Environmental Protection Agency's Maximum Contaminant Level or the Secondary Maximum Contaminant Level were dissolved solids and total recoverable iron and manganese.

Rasmussen, P. P.

1998-01-01

301

Dechlorination of PCBs, CAHs, herbicides and pesticides neat and in soils at 25 degrees C using Na/NH3.  

PubMed

Na/NH3 reductions have been used to dehalogenate polychlorinated biphenyls (PCBs), chlorinated aliphatic hydrocarbons (CAHs) and pesticides at diffusion controlled rates at room temperature in model compound studies in both dry NH3 and when water was added. The rate ratio of dechlorination (aliphatic and aromatic compounds) versus reaction of the solvated electron with water is very large, allowing wet soils or sludges to be remediated without an unreasonable consumption of sodium. Several soils, purposely contaminated with 1,1,1-trichloroethane, 1-chlorooctane and tetrachloroethylene, were remediated by slurring the soils in NH3 followed by addition of sodium. The consumption of sodium per mole of chlorine removed was examined as a function of both the hazardous substrate's concentration in the soil and the amount of water present. The Na consumption per Cl removed increases as the amount of water increases and as the substrate concentration in soil decreases. However, remediation was still readily accomplished from 5000 to 3000ppm to sub ppm levels of RCl in the presence of substantial amounts of water. PCB- and dioxin-contaminated oils were remediated with Na/NH3 as were PCB-contaminated soils and sludges from contaminated sites. Ca/NH3 treatments also successfully remediated PCB-contaminated clay, sandy and organic soils but laboratory studies demonstrated that Ca was less efficient than Na when substantial amounts of water were present. The advantages of solvated electron reductions using Na/NH3 include: (1) very rapid dehalogenation rates at ambient temperature, (2) soils (even clay soils) break down into particles and slurry nicely in NH3, (3) liquid ammonia handling technology is well known and (4) removal from soils, recovery and recycle of ammonia is easy due to its low boiling point. Finally, dechlorination is extremely fast even for the 'corner' chlorines in the substrate Mirex (structure in Eq. (5)). PMID:11975998

Pittman, Charles U; He, Jinbao

2002-05-01

302

Characterisation of VOCs emitted by open cells receiving municipal solid waste.  

PubMed

This study gives relevant information on the variation of concentrations of certain volatile organic compounds (BTEX, alkanes, organochlorides and terpenes) emitted by open cells receiving municipal solid waste. These compounds represent a large fraction of the total trace components present in landfill gas. The VOC measurements were carried out in the atmosphere of an open landfill cell as a function of time and meteorological parameters, but also as a function of the activity of trucks unloading waste and compaction vehicles, in order to identify the factors that influence VOC emissions. Comparisons were performed systematically between the surface of the open cell and the corresponding mechanical activity. The measurements carried out during the course of the day highlighted the influence of air temperature and waste composition on VOC emissions while measurements of activity showed that the activity of fresh waste compaction vehicles is responsible for the highest VOC emissions. Such information is essential since most of the data in the literature relate to analyses of VOC traces in the biogas network and not in the air of the open cells as a function of different parameters (i.e. meteorological parameters, activity on the site). The highest VOC concentrations (in microg/m3) in the area of an open cell were obtained for: tetrachloroethylene (9810), toluene (8230), limonene (4550), m-xylene (3980) and trichloroethylene (3680). The results showed that the TWA values (the time-weighted average concentrations for up to an 8-h workday) established by INRS/France for the personnel in the station were complied with on the site studied. PMID:17826906

Chiriac, Rodica; Carre, Jean; Perrodin, Yves; Fine, Ludovic; Letoffe, Jean-Marie

2007-08-01

303

In-Situ Remediation of Mixed Radioactive Tank Waste, Via Air Sparging and Poly-Acrylate Solidification  

SciTech Connect

This paper describes remediation activities performed in accordance with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) on an underground storage tank (UST) from the Idaho National Laboratory's Test Area North (TAN) complex. The UST had been used to collect radioactive liquid wastes from and for the TAN evaporator. Recent analyses had found that the residual waste in Tank V-14 had contained quantities of tetrachloroethylene (PCE) in excess of F001 treatment standards. In addition, the residual waste in Tank V-14 was not completely solidified. As a result, further remediation and solidification of the waste was required before the tank could be properly disposed of at the Idaho CERCLA Disposal Facility (ICDF). Remediation of the PCE-contaminated waste in Tank V-14 was performed by first adding sufficient water to fluidize the residual waste in the tank. This was followed by high-volume, in-situ air sparging of the fluidized waste, using air lances that were inserted to the bottom of V-14. The high-volume air sparging removed residual PCE from the fluidized waste, collecting it on granular activated carbon filters within the off-gas system. The sparged waste was then solidified by educting large-diameter crystals of an acrylic acrylate resin manufactured by WaterWorks America{sup TM} into the fluidized waste, via the air-sparging lances. To improve solidification, the air-sparging lances were rotated during the eduction step, while continuing to provide high-volume air flow into the waste. Eduction was continued until the waste had solidified sufficiently to not allow for further eduction of WaterWorks{sup TM} crystals into the waste. The tank was then disposed of at the ICDF, with the residual void volume in the tank filled with cement. (authors)

Farnsworth, R.K.; Edgett, S.M.; Eaton, D.L. [CH2M-WG Idaho, LLC, Idaho Cleanup Projecta, Idaho Falls, ID (United States)

2007-07-01

304

Use of nanosized catalysts for transformation of chloro-organic pollutants.  

PubMed

A new method to transform anthropogenic, chloro-organic compounds (COC) by use of nanosized molecular catalysts immobilized in sol-gel matrixes is presented. COC represent a serious threat to soil and groundwater quality. Metalloporphyrinogens are nanometer sized molecules that are known to catalyze degradation of COC by reduction reactions. In the current study, metalloporphyrinogens were immobilized in sol--gel matrixes with pore throat diameters of nanometers. The catalytic activity of the matrix arrays for anaerobic reduction of tetrachloroethylene (PCE), trichloroethylene (TCE), and carbon tetrachloride (CT) was examined. Experiments were performed under conditions pertinent to groundwater systems, with titanium citrate and zero-valent iron as electron donors. All chloroorganic compounds were reduced in the presence of several sol-gel-metalloporphyrinogen hybrids (heterogeneous catalysts). For example, cobalt-5,10,15,20-(4-hydroxyphenyl)-21H,23H-porphine (TP(OH)P-Co) and cyanocobalamin (vitamin B12) reduced CT concentrations to less than 5% of their initial values in a matter of hours. Cyanocobalamin was found to reduce PCE to trace amounts in less than 48 h and TCE to less than 25% of its initial concentration in 144 h. The reactions were compared to their homogeneous (without sol-gel matrix) analogues. The reduction activity of COC for the homogeneous and heterogeneous systems ranged between similar reactivity in some cases to lower reduction rates for the heterogeneous system. These lower rates are, however, compensated by the ability to encapsulate and reuse the catalyst. Experiments with cyanocobalamin showed that the catalyst could be reused over at least 12 successive cycles of 24 h each. PMID:15787368

Dror, Ishai; Baram, Dana; Berkowitz, Brian

2005-03-01

305

Soil vapor survey at the LLNL site 300 general services area, adjacent portions of the Connolly and Gallo Ranches and the site 300 landfill pit 6 area  

SciTech Connect

During October through December 1988, a soil vapor survey was conducted by Weiss Associates at the Lawrence Livermore National Laboratory Site 300 General Services Area (GSA), adjacent portions of the Connolly and Gallo Ranches, and at the Site 300 Landfill Pit 6 area. The purpose of the investigation was to aid in identifying the sources and the extent of trichloroethylene (TCE) previously found in ground water and soil at, or near, these sites. Using a soil vapor probe, samples were collected at 133 locations from depths of 2 to 15 ft below the surface. Analyses were initially done in the field using a Photovac portable gas chromatograph with a photoionization detector calibrated to detect TCE. During the later portion of the study a mobile laboratory was used that had a gas chromatograph equipped with both Hall electroconductivity and photoionization detectors. This permitted identification of the spectrum of EPA Method 601 volatile organic compounds (VOCs) by a modified EPA Method 8010. Extensive quality assurance/quality control (QA/QC) procedures were followed to ensure consistent system performance and no cross-contamination between samples or sites. Soil vapor concentrations were measured in parts per million on a volume to volume basis (ppM/sub v/v/). TCE concentrations detected in the soil vapor ranged from a high of 628 ppM/sub v/v/ to a low of not detected (ND) at less than 0.001--0.005 ppM/sub v/v/. The highest concentration was found next to monitor well W-7F, near a decommissioned drywell (sump) at the southern boundary of the GSA. Several locations exhibited ND concentrations. Fourteen locations analyzed by a mobile laboratory had tetrachloroethylene (PCE), 1,1-dichloroethylene (1,1-DCE) and/or 1,1,1-trichloroethane (1,1,1-TCA) at concentrations considerably lower than the TCE in the same sample. 17 refs., 15 figs., 2 tabs.

Vonder Haar, S.; Pavletich, J.; McIlvride, W.; Taffet, M.

1989-04-04

306

Design of micellar-enhanced ultrafilters  

SciTech Connect

A systematic calculational procedure is developed for the design of micellar-enhanced ultrafilters to treat aqueous streams contaminated with organic pollutants. Flat plate, spiral wound, hollow fiber, and tubular modules are evaluated for performance and cost. Membranes having a 5,000 molecular weight cutoff (MWCO), which reject all micelles, and 50,000 MWCO membranes, which do not, are used as examples. The surfactant considered is hexadecyl(=cetyl)pyridinium chloride (CPC), and the organic pollutants are chlorobenzene, trichloroethylene, tetrachloroethylene, and toluene. A combined osmotic-pressure and fouling-resistance model quantifies the ultrafiltration permeate flux. Also important are the molar solubilization ratios of the respective organics in aqueous CPC solutions, the osmotic pressure of the surfactant as a function of concentration, and the intrinsic rejection behavior of the membranes for surfactant monomers and micelles. For treatment of 2,000 gal/day of wastewater saturated with chlorobenzene, the optimal design consists of a 3 equilibrium stage system using 18 tubular 50,000 MWCO modules in the first stage operating at 207 kPa, 2 spiral wound 50,000 MWCO modules in the second stage operating at 207 kPa, and 2 spiral wound 5,000 MWCO modules operating at 1,034 kPa in the final stage. The optimum volume concentration ratio is 6; the surfactant concentrate leaves the ultrafilter at 17 kg/m{sup 3}, and the crossflow velocity is 2 m/s in each stage. This design eliminates the need for prefiltration of the total feed and minimizes capital and operating costs.

Markels, J.H.; Lynn, S.; Radke, C.J. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering

1995-07-01

307

Semi-analytical Solution of One-dimensional Multispecies Reactive Transport in a Permeable Reactive Barrier-aquifer System  

NASA Astrophysics Data System (ADS)

Permeable reactive barriers (PRBs) have been accepted by the EPA as an effective groundwater remediation technology. Effective implementation of this in-situ technology requires accurate site characterization to identify the chemicals of concern (COCs) present, their interactions (if any), and their required residence time in the PRB to achieve regulatory concentrations at the point of compliance (POC). Therefore, minimizing performance uncertainties in the design phase is key. Among these uncertainties determining the required PRB thickness is the most important and has been examined in other studies. Less attention, however, has been devoted to developing a practical yet rigorous tool for modeling multi-species reactive transport in the barrier-aquifer system. In this study Park and Zhan’s [2009] mass conservative semi-analytical solution - developed to calculate the required PRB thickness based on the decay of one species - is expanded to four reactive species. For example, the expanded solution could be used to model the degradation pathway from tetrachloroethylene (PCE) to vinyl chloride (VC). The solution is presented in two forms: The steady-state solution programmed into Excel can quickly assist designers in determining the required PRB thickness so that all COCs involved in the degradation pathway achieve regulatory limits at the POC. The second form is the transient solution which is solved by numerically inverting the Laplace transform. The semi-analytical solution presented in this study has several advantages over prior solutions. For example, the influent and effluent boundary conditions of the PRB are mass conservative and both dispersion and decay rate differences between the PRB and aquifer are considered. In addition, the transient solution allows for different retardation factors to be considered in both transport media and for each species.

Mieles, J. M.; Zhan, H.

2010-12-01

308

Simultaneous analysis of 28 urinary VOC metabolites using ultra high performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI/MSMS).  

PubMed

Volatile organic compounds (VOCs) are ubiquitous in the environment, originating from many different natural and anthropogenic sources, including tobacco smoke. Long-term exposure to certain VOCs may increase the risk for cancer, birth defects, and neurocognitive impairment. Therefore, VOC exposure is an area of significant public health concern. Urinary VOC metabolites are useful biomarkers for assessing VOC exposure because of non-invasiveness of sampling and longer physiological half-lives of urinary metabolites compared with VOCs in blood and breath. We developed a method using reversed-phase ultra high performance liquid chromatography (UPLC) coupled with electrospray ionization tandem mass spectrometry (ESI/MSMS) to simultaneously quantify 28 urinary VOC metabolites as biomarkers of exposure. We describe a method that monitors metabolites of acrolein, acrylamide, acrylonitrile, benzene, 1-bromopropane, 1,3-butadiene, carbon-disulfide, crotonaldehyde, cyanide, N,N-dimethylformamide, ethylbenzene, ethylene oxide, propylene oxide, styrene, tetrachloroethylene, toluene, trichloroethylene, vinyl chloride and xylene. The method is accurate (mean accuracy for spiked matrix ranged from 84 to 104%), sensitive (limit of detection ranged from 0.5 to 20 ng mL(-1)) and precise (the relative standard deviations ranged from 2.5 to 11%). We applied this method to urine samples collected from 1203 non-smokers and 347 smokers and demonstrated that smokers have significantly elevated levels of tobacco-related biomarkers compared to non-smokers. We found significant (p<0.0001) correlations between serum cotinine and most of the tobacco-related biomarkers measured. These findings confirm that this method can effectively quantify urinary VOC metabolites in a population exposed to volatile organics. PMID:23062436

Alwis, K Udeni; Blount, Benjamin C; Britt, April S; Patel, Dhrusti; Ashley, David L

2012-04-21

309

[Organohalogen contamination of a dialysis-water treatment plant].  

PubMed

On March 2001 the regular quality control test of the water used for dialysis in an urban centre using a reverse osmosis system revealed a high level of organo-halogenated contamination. The compounds implicated were: trichloroethylene (trielene) [M.Wt. 131 D], tetrachloroethylene, trichloromethane (chloroform) [M.Wt. 121 D], chlorodibromomethane. The dialysis unit was closed. Water samples were analysed in duplicate. The table shows the values (in ppm or microgram/l) obtained for chloroform at the given times: March 8th, altered sample; March 12th, confirmation sample; March 16th, after osmosis membranes change; March 22nd, after carbon filtration replacement; March 26th, after softener resins substitution. The AAMI doesn't recommend any value for organo-halogenated compounds in dialysis water. In the past, the European Pharmacopoeia and the Italian Health Ministry released some reference values for tap water, values which were extended to water used for dialysis. The values are 1 ppm as reference value, 30 ppm as maximum accepted value for the sum of all organo-halogenated compounds, and 10 ppm as the recommended value. In conclusion, the problem was solved by progressive replacement of the components of the water treatment system, even though the real cause remained undetermined. No clinical symptom was recorded and no level of chloroform or trielene was detected in patients' sera despite the low molecular weight and low protein binding of the compounds. A strict control of the water quality and a more comprehensive and updated reference guide are needed for better and safer dialysis delivery. PMID:12369053

Formica, M; Vallero, A; Forneris, G; Cesano, G; Pozzato, M; Borca, M; Iadarola, G M; Quarello, F

310

Investigating the role of atomic hydrogen on chloroethene reactions with iron using tafel analysis and electrochemical impedance spectroscopy.  

PubMed

Metallic iron filings are commonly employed as reducing agents in permeable barriers used for remediating groundwater contaminated by chlorinated solvents. Reactions of trichloroethylene (TCE) and tetrachloroethylene (PCE) with zerovalent iron were investigated to determine the role of atomic hydrogen in their reductive dechlorination. Experiments simultaneously measuring dechlorination and iron corrosion rates were performed to determine the fractions of the total current going toward dechlorination and hydrogen evolution. Corrosion rates were determined using Tafel analysis, and dechlorination rates were determined from rates of byproduct generation. Electrochemical impedance spectroscopy (EIS) was used to determine the number of reactions that controlled the observed rates of chlorocarbon disappearance, as well as the role of atomic hydrogen in TCE and PCE reduction. Comparison of iron corrosion rates with those for TCE reaction showed that TCE reduction occurred almost exclusively via atomic hydrogen at low pH values and via atomic hydrogen and direct electron transfer at neutral pH values. In contrast, reduction of PCE occurred primarily via direct electron transfer at both low and neutral pH values. At low pH values and micromolar concentrations, TCE reaction rates were faster than those for PCE due to more rapid reduction of TCE by atomic hydrogen. At neutral pH values and millimolar concentrations, PCE reaction rates were faster than those for TCE. This shift in relative reaction rates was attributed to a decreasing contribution of the atomic hydrogen reaction mechanism with increasing halocarbon concentrations and pH values. The EIS data showed that all the rate limitations for TCE and PCE dechlorination occurred during the transfer of the first two electrons. Results from this study show that differences in relative reaction rates of TCE and PCE with iron are dependent on the significance of the reduction pathway involving atomic hydrogen. PMID:12967110

Wang, Jiankang; Farrell, James

2003-09-01

311

CROWTM PROCESS APPLICATION FOR SITES CONTAMINATED WITH LIGHT NON-AQUEOUS PHASE LIQUIDS AND CHLORINATED HYDROCARBONS  

SciTech Connect

Western Research Institute (WRI) has successfully applied the CROWTM (Contained Recovery of Oily Wastes) process at two former manufactured gas plants (MGPs), and a large wood treatment site. The three CROW process applications have all occurred at sites contaminated with coal tars or fuel oil and pentachlorophenol (PCP) mixtures, which are generally denser than water and are classified as dense non-aqueous phase liquids (DNAPLs). While these types of sites are abundant, there are also many sites contaminated with gasoline, diesel fuel, or fuel oil, which are lighter than water and lie on top of an aquifer. A third site type occurs where chlorinated hydrocarbons have contaminated the aquifer. Unlike the DNAPLs found at MGP and wood treatment sites, chlorinated hydrocarbons are approximately one and a half times more dense than water and have fairly low viscosities. These contaminants tend to accumulate very rapidly at the bottom of an aquifer. Trichloroethylene (TCE) and perchloroethylene, or tetrachloroethylene (PCE), are the major industrial chlorinated solvents that have been found contaminating soils and aquifers. The objective of this program was to demonstrate the effectiveness of applying the CROW process to sites contaminated with light non-aqueous phase liquids (LNAPLs) and chlorinated hydrocarbons. Individual objectives were to determine a range of operating conditions necessary to optimize LNAPL and chlorinated hydrocarbon recovery, to conduct numerical simulations to match the laboratory experiments and determine field-scale recoveries, and determine if chemical addition will increase the process efficiency for LNAPLs. The testing consisted of twelve TCE tests; eight tests with PCE, diesel, and wood treatment waste; and four tests with a fuel oil-diesel blend. Testing was conducted with both vertical and horizontal orientations and with ambient to 211 F (99 C) water or steam. Residual saturations for the horizontal tests ranged from 23.6% PV to 0.3% PV. Also conducted was screening of 13 chemicals to determine their relative effectiveness and the selection of three chemicals for further testing.

L.A. Johnson, Jr.

2003-06-30

312

A national reconnaissance for pharmaceuticals and other organic wastewater contaminants in the United States--II) untreated drinking water sources.  

PubMed

Numerous studies have shown that a variety of manufactured and natural organic compounds such as pharmaceuticals, steroids, surfactants, flame retardants, fragrances, plasticizers and other chemicals often associated with wastewaters have been detected in the vicinity of municipal wastewater discharges and livestock agricultural facilities. To provide new data and insights about the environmental presence of some of these chemicals in untreated sources of drinking water in the United States targeted sites were sampled and analyzed for 100 analytes with sub-parts per billion detection capabilities. The sites included 25 ground- and 49 surface-water sources of drinking water serving populations ranging from one family to over 8 million people. Sixty-three of the 100 targeted chemicals were detected in at least one water sample. Interestingly, in spite of the low detection levels 60% of the 36 pharmaceuticals (including prescription drugs and antibiotics) analyzed were not detected in any water sample. The five most frequently detected chemicals targeted in surface water were: cholesterol (59%, natural sterol), metolachlor (53%, herbicide), cotinine (51%, nicotine metabolite), beta-sitosterol (37%, natural plant sterol), and 1,7-dimethylxanthine (27%, caffeine metabolite); and in ground water: tetrachloroethylene (24%, solvent), carbamazepine (20%, pharmaceutical), bisphenol-A (20%, plasticizer), 1,7-dimethylxanthine (16%, caffeine metabolite), and tri (2-chloroethyl) phosphate (12%, fire retardant). A median of 4 compounds were detected per site indicating that the targeted chemicals generally occur in mixtures (commonly near detection levels) in the environment and likely originate from a variety of animal and human uses and waste sources. These data will help prioritize and determine the need, if any, for future occurrence, fate and transport, and health-effects research for subsets of these chemicals and their degradates most likely to be found in water resources used for drinking water in the United States. PMID:18433838

Focazio, Michael J; Kolpin, Dana W; Barnes, Kimberlee K; Furlong, Edward T; Meyer, Michael T; Zaugg, Steven D; Barber, Larry B; Thurman, Michael E

2008-04-23

313

Alkyl nitrates, nonmethane hydrocarbons, and halocarbon gases over the equatorial Pacific Ocean during SAGA 3  

NASA Astrophysics Data System (ADS)

The third joint Soviet-American Gases and Aerosols (SAGA 3) experiment was a research cruise conducted aboard the Akademik Korolev in February and March 1990. The cruise covered a region of the equatorial Pacific Ocean from 15°N to 10°S latitude and 144° to 165°W longitude. On this cruise we collected samples for the measurement of alkyl nitrates (RONO2), nonmethane hydrocarbons (NMHC) and several halocarbon gases. Though there are few data available for comparison in this region of the marine boundary layer, the mixing ratios of the trace gases we measured are within the range of prior measurements in the remote atmosphere. Latitudinal gradients were found for trace gases with predominantly anthropogenic sources, e.g., methylene chloride, tetrachloroethylene, and acetylene; higher concentrations in the North Pacific atmosphere decreased slowly across the Equator to the South Pacific. More stable gases, e.g. methyl chloride and methyl bromide, had no pronounced variation across the equator. A biogenic source of two organobromine compounds, bromoform and dibromochloromethane, was indicated by maximum mixing ratios of these species over the equator where indicators of biological productivity (e.g., chlorophyll) in the surface ocean water also maximized. Alkyl nitrates were found at levels higher than predicted from steady state calculations based on measured mixing ratios of hydrocarbons and NO. The measured levels of RONO2 suggest long-range transport as one mechanism contributing to elevated concentrations of alkyl nitrates in the remote troposphere. However, the distributions of C2 and C3 alkyl nitrates over the equator were similar to the organobromine gases. This distribution suggests a possible oceanic source for alkyl nitrates to the atmosphere.

Atlas, E.; Pollock, W.; Greenberg, J.; Heidt, L.; Thompson, A. M.

1993-01-01

314

Effect of Clay on DNAPL Mobilization During Alcohol Flushing  

NASA Astrophysics Data System (ADS)

An improved understanding of dense non-aqueous phase liquid (DNAPL) behavior in clay-containing porous media is critical for improving restoration attempts using in-situ remediation techniques such as alcohol flushing. Clay type and clay fraction at the pore scale affect initial DNAPL distribution and potential mobilization during alcohol flushing. Mobilization experiments were performed on columns containing well-sorted Ottawa white sand and columns containing sand with a 10 percent clay fraction. The clays used were Kaolinite and Ca-montmorillonite. The columns were characterized for pore-size distribution using pressure-saturation experiments and brought to a residual tetrachloroethylene (PCE) saturation before flushing. Successive increments of isopropyl alcohol (IPA) were flushed through the columns to determine the alcohol concentration at the onset of mobilization. In columns containing pure sand and 10 percent Kaolinite (K10), PCE mobilized at approximately the same IPA concentration. PCE mobilized with a much lower IPA concentration in columns containing 10 percent Ca-montmorillonite (M10) indicating that Ca-montmorillonite is affecting DNAPL mobilization. The mobilization at lower IPA concentrations may be due to differing pore sizes and pore-size distributions resulting from the clay type, clay colloid detachment during flushing, interfacial interactions between clay, DNAPL and the pore fluid or some combination of these factors. Pressure-saturation relationships show smaller pores and a greater pore size distribution in the M10 columns. Colloids were observed in the effluent in many experiments and a statistically significant decrease in PCE/water interfacial tension was measured in solutions containing Ca-montmorillonite colloids.

Rossman, A. J.; Hayden, N. J.; Matmon, D.

2001-05-01

315

Distribution of volatile organic compounds in a New Jersey coastal plain aquifer system  

USGS Publications Warehouse

Samples for analysis of volatile organic compounds were collected from 315 wells in the Potomac-Raritan-Magothy aquifer system in southwestern New Jersey and a small adjacent area in Pennsylvania during 1980-82. Volatile organic compounds were detected in all three aquifer units of the Potomac-Raritan-Magoth aquifer system in the study area. Most of the contamination appears to be confined to the outcrop area at present. Low levels of contamination, however, were found downdip of the outcrop area in the upper and middle aquifers. Trichloroethylene, tetrachloroethylene, and benzene were the most frequently detected compounds. Differences in the areal distributions of light chlorinated hydrocarbons, such as trichloroethylene, and aromatic hydrocarbons, such as benzene, were noted and are probably due to differences in the uses of the compounds and the distribution patterns of potential contamination sources. The distribution patterns of volatile organic compounds differed greatly among the three aquifer units. The upper aquifer, which crops out mostly in less-developed areas, had the lowest percentage of wells with volatile organic compounds detected (10 percent of wells sampled). The concentrations in most wells in the upper aquifer which had detectable levels were less than 10 ??g/l. In the middle aquifer, which crops out beneath much of the urban and industrial area adjacent to the Delaware River, detectable levels of volatile organic compounds were found in 22 percent of wells sampled, and several wells contained concentrations above 100 ??g/l. The lower aquifer, which is confined beneath much of the outcrop area of the aquifer system, had the highest percentage of wells (28 percent) with detectable levels. This is probably due to (1) vertical leakage of contamination from the middle aquifer, and (2) the high percentage of wells tapping the lower aquifer in the most heavily developed areas of the outcrop.

Fusillo, T. V.; Hochreiter, Jr. , J. J.; Lord, D. G.

1985-01-01

316

Field demonstration of surfactant-enhanced solubilization of DNAPL at Dover Air Force Base, Delaware  

NASA Astrophysics Data System (ADS)

This study reports on a surfactant-based flood for tetrachloroethylene (PCE) removal from a control test cell at the Dover National Test Site. The surfactant formulation (sodium dihexyl sulfosuccinate (Aerosol-MA® or AMA), isopropanol and calcium chloride) was able to achieve a high concentration of PCE in swollen micelles (supersolubilization) without vertical PCE migration. The hydraulic system included eight screened wells that were operated in both vertical circulation and line drive configurations. After 10 pore volumes of flushing, the overall PCE removal was 68% (65% of which corresponded to the surfactant flooding alone). In addition, the residual PCE saturation was reduced from 0.7% to 0.2%, and the concentration of PCE in the groundwater was reduced from 37 190 mg/L before the flushing to 7.3 mg/L after flooding. Recycling the surfactant solution reduced the required surfactant mass (and thus cost, and waste) by 90%. Close to 80% of the total PCE removal was obtained during the first five pore volumes which were operated in an upward vertical circulation flow scheme. No free oil phase was observed during the test. Further analysis of multilevel sampler data suggests that most of the trapped oil remaining in the cell was likely localized in secluded regions of the aquifer, which helps explain the lower PCE groundwater concentration after remedial activities. In summary, this field study demonstrated the feasibility of surfactant-enhanced remediation to reduce the mass in the source zone and significantly reduce the PCE aqueous concentration and therefore the risk associated with the contaminant plume.

Childs, Jeffrey; Acosta, Edgar; Annable, Michael D.; Brooks, Michael C.; Enfield, Carl G.; Harwell, Jeffrey H.; Hasegawa, Mark; Knox, Robert C.; Rao, P. Suresh C.; Sabatini, David A.; Shiau, Ben; Szekeres, Erika; Wood, A. Lynn

2006-01-01

317

Characterization of the Chronic Risk and Hazard of Hazardous Air Pollutants in the United States Using Ambient Monitoring Data  

PubMed Central

Background Ambient measurements of hazardous air pollutants (air toxics) have been used to validate model-predicted concentrations of air toxics but have not been used to perform risk screening at the national level. Objectives We used ambient concentrations of routinely measured air toxics to determine the relative importance of individual air toxics for chronic cancer and noncancer exposures. Methods We compiled 3-year averages for ambient measurement of air toxics collected at monitoring locations in the United States from 2003 through 2005. We then used national distributions of risk-weighted concentrations to identify the air toxics of most concern. Results Concentrations of benzene, carbon tetrachloride, arsenic, 1,3-butadiene, and acetaldehyde were above the 10?6 cancer risk level at most sites nationally with a high degree of confidence. Concentrations of tetrachloroethylene, ethylene oxide, acrylonitrile, and 1,4-dichlorobenzene were also often greater than the 10?6 cancer risk level, but we have less confidence in the estimated risk associated with these pollutants. Formaldehyde and chromium VI concentrations were either above or below the 10?6 cancer risk level, depending on the choice of agency-recommended 10?6 level. The method detection limits of eight additional pollutants were too high to rule out that concentrations were above the 10?6 cancer risk level. Concentrations of 52 compounds compared with chronic noncancer benchmarks indicated that only acrolein concentrations were greater than the noncancer reference concentration at most monitoring sites. Conclusions Most pollutants with national site-level averages greater than health benchmarks were also pollutants of concern identified in modeled national-scale risk assessments. Current monitoring networks need more sensitive ambient measurement techniques to better characterize the air toxics problem in the United States.

McCarthy, Michael C.; O'Brien, Theresa E.; Charrier, Jessica G.; Hafner, Hilary R.

2009-01-01

318

Determinants of personal, indoor and outdoor VOC concentrations: An analysis of the RIOPA data.  

PubMed

Community and environmental exposure to volatile organic compounds (VOCs) has been associated with a number of emission sources and activities, e.g., environmental tobacco smoke and pumping gasoline. Such factors have been identified from mostly small studies with relatively limited information regarding influences on VOC levels. This study uses data from the Relationship of Indoor Outdoor and Personal Air (RIOPA) study to investigate environmental, individual and social determinants of VOC concentrations. RIOPA included outdoor, indoor and personal measurements of 18 VOCs from 310 non-smoking households and adults in three cities and two seasons, and collected a wide range of information pertaining to participants, family members, households, and neighborhoods. Exposure determinants were identified using stepwise regressions and linear mixed-effect models. Most VOC exposure (66 to 78% of the total exposure, depending on VOC) occurred indoors, and outdoor VOC sources accounted for 5 (d-limonene) to 81% (carbon tetrachloride) of the total exposure. Personal exposure and indoor measurements had similar determinants, which depended on the VOC. Gasoline-related VOCs (e.g., benzene, methyl tertiary butyl ether) were associated with city, residences with attached garages, self-pumping of gas, wind speed, and house air exchange rate (AER). Odorant and cleaning-related VOCs (e.g., 1,4-dichlorobenzene and chloroform) also were associated with city and AER, and with house size and family members showering. Dry-cleaning and industry-related VOCs (e.g., tetrachloroethylene and trichloroethylene) were associated with city, residence water supply type, and dry-cleaner visits. These and other relationships were significant, explained from 10 to 40% of the variation, and are consistent with known emission sources and the literature. Outdoor concentrations had only two common determinants: city and wind speed. Overall, personal exposure was dominated by the home setting, although a large fraction of VOC concentrations were due to outdoor sources. City, personal activities, household characteristics and meteorology were significant determinants. PMID:24034784

Su, Feng-Chiao; Mukherjee, Bhramar; Batterman, Stuart

2013-09-10

319

Biodesulfurization techniques: Application of selected microorganisms for organic sulfur removal from coals. Final report  

SciTech Connect

As an alternative to post-combustion desulfurization of coal and pre-combustion desulfurization using physicochemical techniques, the microbial desulfurization of coal may be accomplished through the use of microbial cultures that, in an application of various microbial species, may remove both the pyritic and organic fractions of sulfur found in coal. Organisms have been isolated that readily depyritize coal but often at prohibitively low rates of desulfurization. Microbes have also been isolated that may potentially remove the organic-sulfur fraction present in coal (showing promise when acting on organic sulfur model compounds such as dibenzothiophene). The isolation and study of microorganisms demonstrating a potential for removing organic sulfur from coal has been undertaken in this project. Additionally, the organisms and mechanisms by which coal is microbially depyritized has been investigated. Three cultures were isolated that grew on dibenzothiophene (DBT), a model organic-sulfur compound, as the sole sulfur source. These cultures (UMX3, UMX9, and IGTS8) also grew on coal samples as the sole sulfur source. Numerous techniques for pretreating and ``cotreating`` coal for depyritization were also evaluated for the ability to improve the rate or extent of microbial depyritization. These include prewashing the coal with various solvents and adding surfactants to the culture broth. Using a bituminous coal containing 0.61% (w/w) pyrite washed with organic solvents at low slurry concentrations (2% w/v), the extent of depyritization was increased approximately 25% in two weeks as compared to controls. At slurry concentrations of 20% w/v, a tetrachloroethylene treatment of the coal followed by depyritization with Thiobacillus ferrooxidans increased both the rate and extent of depyritization by approximately 10%.

Elmore, B.B.

1993-08-01

320

Determination of bisphenol A and bisphenol B in canned seafood combining QuEChERS extraction with dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry.  

PubMed

A new simple and reliable method combining an acetonitrile partitioning extractive procedure followed by dispersive solid-phase cleanup (QuEChERS) with dispersive liquid-liquid microextraction (DLLME) and further gas chromatography mass spectrometry analysis was developed for the simultaneous determination of bisphenol A (BPA) and bisphenol B (BPB) in canned seafood samples. Besides the great enrichment factor provided, the final DLLME extractive step was designed in order to allow the simultaneous acetylation of the compounds required for their gas chromatographic analysis. Tetrachloroethylene was used as extractive solvent, while the acetonitrile extract obtained from QuEChERS was used as dispersive solvent, and anhydride acetic as derivatizing reagent. The main factors influencing QuEChERS and DLLME efficiency including nature of QuEChERS dispersive-SPE sorbents, amount of DLLME extractive and dispersive solvents and nature and amount of derivatizing reagent were evaluated. DLLME procedure provides an effective enrichment of the extract, allowing the required sensitivity even using a single quadropole MS as detector. The optimized method showed to be accurate (>68 % recovery), reproducible (<21 % relative standard deviation) and sensitive for the target analytes (method detection limits of 0.2 ?g/kg for BPA and 0.4 ?g/kg for BPB). The screening of several canned seafood samples commercialized in Portugal (total = 47) revealed the presence of BPA in more than 83 % of the samples with levels ranging from 1.0 to 99.9 ?g/kg, while BPB was found in only one sample at a level of 21.8 ?g/kg. PMID:22995997

Cunha, S C; Cunha, C; Ferreira, A R; Fernandes, J O

2012-09-21

321

Reductive capacity of natural reductants.  

PubMed

Reductive capacities of soil minerals and soil for Cr(VI) and chlorinated ethylenes were measured and characterized to provide basic knowledge for in-situ and ex-situ treatment using these natural reductants. The reductive capacities of iron-bearing sulfide (pyrite), hydroxide (green rust; GR(SO4)), and oxide (magnetite) minerals for Cr(VI) and tetrachloroethylene (PCE) were 1-3 orders of magnitude greater than those of iron-bearing phyllosilicates (biotite, vermiculite, and montmorillonite). The reductive capacities of surface soil collected from the plains of central Texas were similar and slightly greater than those of iron-bearing phyllosilicates. The reductive capacity of iron-bearing soil minerals for Cr(VI) was roughly 3-16 times greater than that for PCE, implying that Cr(VI) is more susceptible to being reduced by soil minerals than is PCE. GR(SO4) has the greatest reductive capacity for both Cr(VI) and PCE followed by magnetite, pyrite, biotite, montmorillonite, and vermiculite. This order was the same for both target compounds, which indicates that the relative reductive capacities of soil minerals are consistent. The reductive capacities of pyrite and GR(SO4) for chlorinated ethylenes decreased in the order: trichloroethylene (TCE) > PCE > cis-dichloroethylene (c-DCE) > vinyl chloride (VC). Fe(II) content in soil minerals was directly proportional to the reductive capacity of soil minerals for Cr(VI) and PCE, suggesting that Fe(II) content is an important factor that significantly affects reductive transformations of target contaminants in natural systems. PMID:12630469

Lee, Woojin; Batchelor, Bill

2003-02-01

322

Distributions and sea-to-air fluxes of volatile halocarbons in the East China Sea in early winter.  

PubMed

The concentrations of six volatile halogenated organic compounds (VHOC)-chloroform (CHCl(3)), trichloroethylene (C(2)HCl(3)), tetrachloroethylene (C(2)Cl(4)), carbon tetrachloride (CCl(4)), methylchloroform (CH(3)CCl(3)), and bromoform (CHBr(3)) in the East China Sea (ECS) in November and December 2010 were measured by a purge and trap system coupled to a gas chromatograph with an electron capture detection (ECD). Mean (range) concentrations of CHCl(3), C(2)HCl(3), C(2)Cl(4), CH(3)CCl(3), CCl(4) and CHBr(3) in the surface water were 16.90 (0.40-62.92), 16.27 (2.78-83.33), 2.40 (0.39-9.33), 32.29 (19.72-57.68), 1.70 (0.39-8.73) and 17.11 (4.33-34.46) pM, respectively. With the exception of C(2)HCl(3), the concentrations of other five kinds of VHOC generally exhibited a decreasing trend with distance from the coast, with the low values found in the open sea. The anthropogenic sources contributed to the elevated levels of CCl(4) and CH(3)CCl(3), whereas a combination of the anthropogenic and biogenic sources might be responsible for the elevated levels of CHCl(3), C(2)HCl(3), C(2)Cl(4) and CHBr(3). In the depth profiles, vertical distributions of the six VHOC in the water column were complicated, with the maxima occurring at 0-100 m depths. The mean sea-to-air fluxes of CHCl(3), C(2)HCl(3), C(2)Cl(4) and CHBr(3) were estimated to be 21.08, 29.94, 2.05 and 35.50 nmol m(-2) d(-1), respectively, indicating that the ECS was a source for the four VHOC in the atmosphere. PMID:23102696

He, Zhen; Yang, Gui-Peng; Lu, Xiao-Lan

2012-10-25

323

VOCs in Non-Arid Soils Integrated Demonstration: Technology summary  

SciTech Connect

The Volatile Organic Compounds (VOCs) in Non-Arid Soils Integrated Demonstration (ID) was initiated in 1989. Objectives for the ID were to test the integrated demonstration concept, demonstrate and evaluate innovative technologies/systems for the remediation of VOC contamination in soils and groundwater, and to transfer technologies and systems to internal and external customers for use in fullscale remediation programs. The demonstration brought together technologies from DOE laboratories, other government agencies, and industry for demonstration at a single test bed. The Savannah River Site was chosen as the location for this ID as the result of having soil and groundwater contaminated with VOCS. The primary contaminants, trichlorethylene and tetrachloroethylene, originated from an underground process sewer line servicing a metal fabrication facility at the M-Area. Some of the major technical accomplishments for the ID include the successful demonstration of the following: In situ air stripping coupled with horizontal wells to remediate sites through air injection and vacuum extraction; Crosshole geophysical tomography for mapping moisture content and lithologic properties of the contaminated media; In situ radio frequency and ohmic heating to increase mobility, of the contaminants, thereby speeding recovery and the remedial process; High-energy corona destruction of VOCs in the off-gas of vapor recovery wells; Application of a Brayton cycle heat pump to regenerate carbon adsorption media used to trap VOCs from the offgas of recovery wells; In situ permeable flow sensors and the colloidal borescope to determine groundwater flow; Chemical sensors to rapidly quantify chlorinated solvent contamination in the subsurface; In situ bioremediation through methane/nutrient injection to enhance degradation of contaminants by methanotrophic bateria.

Not Available

1994-02-01

324

Piezo-resistivity electric cone penetration technology investigation of the M-basin at the Savannah River Site, Aiken, South Carolina. Progress report, May 1, 1992--October 31, 1992  

SciTech Connect

This report documents the results of a combined field and laboratory investigation program to: (1) delineate the geologic layering and (2) determine the location of a dense non-aqueous liquid-phase (DNAPL) contaminated plume beneath the M Area Hazardous Waste Management Facility at the Savannah River Plant. During April of 1991, DNAPLs were detected in monitoring well (MSB-3D), located adjacent to the capped M-Area Settling Basin. Solvents in the well consisted mainly of tetrachloroethylene and trichloroethylene, which are also the main solvents found in groundwater in the M Area. In permeable soils, DNAPLs move downward rapidly due to their high density and low viscosity as compared to water. Within the vadose zone, DNAPLs tend to be held by the less permeable clay and silts by capillary force. In the saturated zone, the downward movement is slowed by clays and silts and the DNAPL tends to pool on this layer, then spread laterally. The lateral movement continues until a permeable layer is encountered, which can be a sand lens, fracture or other high conductivity seam. The DNAPL then moves downward, until another low permeability layer is encountered. Applied Research Associates was contracted to conduct a program to: (1) field demonstrate the utility of Cone Penetration Technology to investigate DOE contaminant sites and, (2) conduct a laboratory and field program to evaluate the use of electric resistivity surveys to locate DNAPL contaminated soils. The field program was conducted in the M-Basin and laboratory tests were conducted on samples from the major stratigraphy units as identified in Eddy et. al. Cone Penetration Technology was selected to investigate the M-Basin as it: (1) is minimally invasive, (2) generates minimal waste, (3) is faster and less costly than drilling, (4) provides continuous, detailed in situ characterization data, (5) permits real-time data processing, and (6) can obtain soil, soil gas, and water samples without the need for a boring.

Bowers, B. [Westinghouse Savannah River Co., Aiken, SC (United States); Rossabi, J.; Shinn, J.D. II; Bratton, W.L. [Applied Research Associates, Inc., South Royalton, VT (United States)

1997-05-01

325

Treatment of chlorinated ethenes in groundwater with ozone and hydrogen peroxide  

SciTech Connect

A study was conducted to enhance the performance of an advanced oxidation process in treating chlorinated ethenes in groundwater at IBM`s groundwater treatment system at its Essex Junction, Vermont facility. A model describing the reaction kinetics and mass transfer of a co-current ozone injection process is presented. This model, in conjunction with experiments, demonstrates that the treatment performance of the ozone treatment process at a given ozone/air concentration and ozone mass flowrate cannot be improved by varying process operating parameters such as number of ozone injectors utilized, use of a static mixer, or variation of groundwater flowrate through each injector. This is because dissolved ozone reaches equilibrium with the injected ozone/air mixture within two seconds of initial contact. Also, the Venturi-type ozone injection system presently in use destroys nearly half of the injected ozone. Injection of hydrogen peroxide in conjunction with ozone increases the overall tetrachloroethylene (PCE) treatment efficiency by a factor of four (in comparison to ozone alone) at a H{sub 2}O{sub 2}/O{sub 3} mass ratio of between 1 and 2. Treatment of trichloroethylene (TCE) is enhanced by a factor of two. This enhancement of the oxidative treatment process results in a reduction in solvent mass load to a granular activated carbon (GAC) adsorption system located downstream, thus potentially reducing the usage GAC and regeneration of spent GAC. However, residual hydrogen peroxide and/or hydroxyl free radicals from the oxidation process effluent may interact adversely with certain grades of GAC; the causes of this interaction and methods to attenuate it (i.e., the use of more resistant grades of GAC) are discussed. Overall O{sub 3}/H{sub 2}O{sub 2}/GAC system operating costs can potentially be reduced significantly (up to $20K annually). An economic analysis and system operation/cost optimization study are presented. 8 refs., 7 figs., 1 tab.

Clancy, P.B. [IBM Corp., Essex Junction, VT (United States); Armstrong, J.; Couture, M. [Dartmouth College, Hanover, NH (United States)] [and others

1996-12-31

326

Systematic selection of off-gas treatment at the Savannah River Site  

SciTech Connect

At the Savannah River Site (SRS), from 1958--1985, effluent waste from the reactor fuel and target rod fabrication area (M-Area) was discharged to a settling basin. In 1981, monitoring wells detected groundwater contamination, specifically trichloroethylene and tetrachloroethylene, in the immediate vicinity of the basin. Under the auspices of Resource Conservation and Recovery Act (RCRA) the M-Area contamination must be addressed by a corrective action program until the volatile organic compound (VOC) concentrations reach Drinking Water Standards. This was initiated in 1985 with startup of a full-scale pump-and-treat air stripper system. Recently, remediation efforts have focused on vacuum extraction to treat vadose zone contamination not addressed by the original recovery wells, and additional pump-and-treat systems to achieve hydraulic control of the plume. Regulatory requirements allowed for discharge of VOCs to the atmosphere when the original remediation system was installed; however, 1990 amendments to the Clean Air Act will eventually require treatment of VOC contaminated air prior to discharge. This has ramifications to systems currently being design, as well as the existing systems. In response to the 1990 Clean Air Act amendments, SRS initiated a study to assess commercially available off-gas treatment technologies. These included carbon adsorption, thermal incineration, catalytic oxidation, absorption, condensation, and UV/peroxide destruction, and xenon flashlamp. Criteria used to evaluate the technologies were the thirty (30) year life cycle cost, permitting considerations, and manpower requirements. The study concluded that catalytic oxidation provided the most desirable combination of these elements.

McKillip, S.T.; Rehder, T.E.

1992-01-01

327

Field demonstration of surfactant-enhanced solubilization of DNAPL at Dover Air Force Base, Delaware.  

PubMed

This study reports on a surfactant-based flood for tetrachloroethylene (PCE) removal from a control test cell at the Dover National Test Site. The surfactant formulation (sodium dihexyl sulfosuccinate (Aerosol-MA or AMA), isopropanol and calcium chloride) was able to achieve a high concentration of PCE in swollen micelles (supersolubilization) without vertical PCE migration. The hydraulic system included eight screened wells that were operated in both vertical circulation and line drive configurations. After 10 pore volumes of flushing, the overall PCE removal was 68% (65% of which corresponded to the surfactant flooding alone). In addition, the residual PCE saturation was reduced from 0.7% to 0.2%, and the concentration of PCE in the groundwater was reduced from 37-190 mg/L before the flushing to 7.3 mg/L after flooding. Recycling the surfactant solution reduced the required surfactant mass (and thus cost, and waste) by 90%. Close to 80% of the total PCE removal was obtained during the first five pore volumes which were operated in an upward vertical circulation flow scheme. No free oil phase was observed during the test. Further analysis of multilevel sampler data suggests that most of the trapped oil remaining in the cell was likely localized in secluded regions of the aquifer, which helps explain the lower PCE groundwater concentration after remedial activities. In summary, this field study demonstrated the feasibility of surfactant-enhanced remediation to reduce the mass in the source zone and significantly reduce the PCE aqueous concentration and therefore the risk associated with the contaminant plume. PMID:16233935

Childs, Jeffrey; Acosta, Edgar; Annable, Michael D; Brooks, Michael C; Enfield, Carl G; Harwell, Jeffrey H; Hasegawa, Mark; Knox, Robert C; Rao, P Suresh C; Sabatini, David A; Shiau, Ben; Szekeres, Erika; Wood, A Lynn

2005-10-17

328

Large-scale high-efficiency air stripper and recovery well network for removing volatile organic chlorocarbons from ground water  

SciTech Connect

The Savannah River Plant (SRP) produces special nuclear materials for the US Government. Since 1958, chemical wastes generated by an aluminum forming/metal finishing process used to manufacture fuel and target assemblies were discharged to a settling basin. This process waste stream contained acids, alkalis, metals, and chlorinated degreasing solvents. In 1981, these solvents, specifically trichloroethylene and tetrachloroethylene, were discovered in monitor wells near the settling basin. A monitor well network was installed to define the vertical and horizontal extent of the plume. The current inventory of total chlorocarbons in the saturated zone is approximately 360,000 pounds within the 100 ppB contour interval. During 1983, air stripping technology was evaluated to remove these solvents from the ground water. A 20-gpm ground water pilot air stripper with one recovery well was tested. Performance data from this unit were then used to design a 50-gpm production prototype air stripper. This unit demonstrated that degreaser solvent concentrations in ground water could be reduced from 120,000 ppB to less than the detection limit of 1 ppB. Data from these two units were then used to design an air stripper column that would process contaminated ground water at a rate of 400 gpm. Water is fed to this column from a network of 11 recovery wells. These wells were located in the zone of contamination, as defined by analytical and numerical modeling techniques. This system has been operational since April 1985. To date, over 65,000 pounds of chlorinated degreaser solvents have been removed from an underlying aquifer. The effects of this program on the hydraulic gradient and contamination movement are currently being evaluated. The purpose of this paper is to describe the ground water remediation program at the Savannah River Plant.

Boone, L F; Lorfenz, R; Muska, C F; Steele, J L

1986-05-01

329

Development and Application of a 3-Dimensional Finite Element Model for Remediation Wellfield Management at Lawrence Livermore National Laboratory  

NASA Astrophysics Data System (ADS)

Lawrence Livermore National Laboratory (LLNL), which is on the Superfund National Priorities List, is implementing an extensive ground water remediation program. The environmental investigation covers an area of about 2 square miles, and is underlain by a thick sequence of heterogeneous alluvial sediments. These sediments have been subdivided into hydrostratigraphic units (HSUs) bounded by thin confining layers that were identified using a deterministic approach. LLNL currently operates a large ground water extraction system that includes 80 ground water extraction wells connected to 25 separate treatment facilities. These combined facilities treated about 308 million gallons of ground water at an average combined flow rate of 600 gpm, and removed about 270 kg of volatile organic compounds (VOC's). To better manage this large complex remediation system, a 3-dimensional, finite-element numerical model was developed using FEFLOW. The model simulated a 7 square-mile portion of the large Livermore Valley ground water basin. The quality of the input data varied from highly detailed, in the environmental investigation areas, to sparse, near some of the model domain boundaries. These different data sets had to be integrated to obtain the necessary boundary conditions and input parameters for the model. Hydraulic conductivities were averaged from measured lithologic descriptions and hydraulic test data. Boundary conditions were based on a local and regional assessment of groundwater elevation data representative of observed inflow/outflow boundaries. The model was initially calibrated to a set of 8 distinct hydrologic stress periods over 12 years. Initial flow calibration for the model was achieved using the parameter estimation tool PEST. Through successive data analysis and calibration, optimal parameters were established for each HSU and expanded to 35 hydrologic stress periods covering the entire recorded hydrologic history. VOC transport was calibrated to 9 years of historical data for tetrachloroethylene (PCE) and trichloroethylene (TCE). There is good agreement between observed and calculated PCE and TCE plume migration and response to remediation activities. The calibrated model is currently being applied to optimize groundwater remediation efforts by testing wellfield management strategies and to assist with long term budgeting and planning purposes. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Mansoor, K.; Maley, M. P.; Demir, Z.; Noyes, C.

2001-12-01

330

Asthma symptoms in Hispanic children and daily ambient exposures to toxic and criteria air pollutants.  

PubMed Central

Although acute adverse effects on asthma have been frequently found for the U.S. Environmental Protection Agency's principal criteria air pollutants, there is little epidemiologic information on specific hydrocarbons from toxic emission sources. We conducted a panel study of 22 Hispanic children with asthma who were 10-16 years old and living in a Los Angeles community with high traffic density. Subjects filled out symptom diaries daily for up to 3 months (November 1999 through January 2000). Pollutants included ambient hourly values of ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide and 24-hr values of volatile organic compounds (VOCs), particulate matter with aerodynamic diameter < 10 microm (PM10, and elemental carbon (EC) and organic carbon (OC) PM10 fractions. Asthma symptom severity was regressed on pollutants using generalized estimating equations, and peak expiratory flow (PEF) was regressed on pollutants using mixed models. We found positive associations of symptoms with criteria air pollutants (O3, NO2, SO2, PM10), EC-OC, and VOCs (benzene, ethylbenzene, formaldehyde, acetaldehyde, acetone, 1,3-butadiene, tetrachloroethylene, toluene, m,p-xylene, and o-xylene). Selected adjusted odds ratios for bothersome or more severe asthma symptoms from interquartile range increases in pollutants were, for 1.4 ppb 8-hr NO2, 1.27 [95% confidence interval (CI), 1.05-1.54]; 1.00 ppb benzene, 1.23 (95% CI, 1.02-1.48); 3.16 ppb formaldehyde, 1.37 (95% CI, 1.04-1.80); 37 microg/m3 PM10, 1.45 (95% CI, 1.11-1.90); 2.91 microg/m3 EC, 1.85 (95% CI, 1.11-3.08); and 4.64 microg/m3 OC, 1.88 (95% CI, 1.12-3.17). Two-pollutant models of EC or OC with PM10 showed little change in odds ratios for EC (to 1.83) or OC (to 1.89), but PM10 decreased from 1.45 to 1.0. There were no significant associations with PEF. Findings support the view that air toxins in the pollutant mix from traffic and industrial sources may have adverse effects on asthma in children.

Delfino, Ralph J; Gong, Henry; Linn, William S; Pellizzari, Edo D; Hu, Ye

2003-01-01

331

Bedrock geology and outcrop fracture trends in the vicinity of the Savage Municipal Well Superfund site, Milford, New Hampshire  

USGS Publications Warehouse

The Savage Municipal Well Superfund site consists of an eastward-directed plume of volatile organic compounds, principally tetrachloroethylene (PCE), in alluvium and glacial sand and gravel in the Souhegan River valley, just south of the river and about 4 kilometers west of the town of Milford, New Hampshire. Sampling of monitoring wells at the site has helped delineate the extent of the plume and has determined that some contaminant has migrated into the underlying crystalline bedrock, including bedrock north of the river within 200 meters of a nearby residential development that was constructed in 1999. Borehole geophysical logging has identified a northeast preferential trend for bedrock fractures, which may provide a pathway for the migration of contaminant under and north of the Souhegan River. The current study investigates the bedrock geologic setting for the site, including its position relative to known regional geologic structures, and compiles new strike and dip measurements of joints in exposed bedrock to determine if there are dominant trends in orientation similar to what was found in the boreholes. The site is located on the northwestern limb of a northeast-trending regional anticlinorium that is southeast of the Campbell Hill fault zone. The Campbell Hill fault zone defines the contact between granite and gneiss of the anticlinorium and granite and schist to the northwest and is locally marked by lenses of massive vein quartz, minor faults, and fracture zones that could potentially affect plume migration. The fault zone was apparently not intercepted by any of the boreholes that were drilled to delineate the contaminant plume and therefore passes to the north of the northernmost borehole in the vicinity of the new residential area. Joints measured in surface exposures indicate a strong preferred direction of strike to the north-northeast corroborating the borehole data and previous outcrop and geophysical studies. The north-northeast preferred direction matches the direction of elongation of the cone of depression formed during a pump test of the bedrock wells and could explain a potential pathway for the migration of contaminant north of the river.

Burton, William C.; Harte, Philip T.

2013-01-01

332

In-Situ Anaerobic Biosurfactant Production Process For Remediation Of DNAPL Contamination In Subsurface Aquifers  

NASA Astrophysics Data System (ADS)

Microbial Enhanced Oil Recovery (MEOR) and remediation of aquifers contaminated with hydrophobic contaminants require insitu production of biosurfactants for mobilization of entrapped hydrophobic liquids. Most of the biosurfactant producing microorganisms produce them under aerobic condition and hence surfactant production is limited in subsurface condition due to lack of oxygen. Currently bioremediation involves expensive air sparging or excavation followed by exsitu biodegradation. Use of microorganisms which can produce biosurfactants under anaerobic conditions can cost effectively expedite the process of insitu bioremediation or mobilization. In this work, the feasibility of anaerobic biosurfactant production in three mixed anaerobic cultures prepared from groundwater and soil contaminated with chlorinated compounds and municipal sewage sludge was investigated. The cultures were previously enriched under complete anaerobic conditions in the presence of Tetrachloroethylene (PCE) for more than a year before they were studied for biosurfactant production. Biosurfactant production under anaerobic conditions was simulated using two methods: i) induction of starvation in the microbial cultures and ii) addition of complex fermentable substrates. Positive result for biosurfactant production was not observed when the cultures were induced with starvation by adding PCE as blobs which served as the only terminal electron acceptor. However, slight reduction in interfacial tension was noticed which was caused by the adherence of microbes to water-PCE interface. Biosurfactant production was observed in all the three cultures when they were fed with complex fermentable substrates and surface tension of the liquid medium was lowered below 35 mN/m. Among the fermentable substrates tested, vegetable oil yielded highest amount of biosurfactant in all the cultures. Complete biodegradation of PCE to ethylene at a faster rate was also observed when vegetable oil was amended to the microbial cultures. The microorganisms responsible for biosurfactant production was isolated and identified as Pseudomonas Sp (designated as Pseudomonas Sp ANBIOSURF-1, Gene bank no: FJ930079), Pseudomonas stutzeri (MTCC 10033), Pseudomonas Sp (MTCC 10032) from groundwater, soil and municipal sewage sludge enrichments respectively. This study confirms that biosurfactants can be produced under anaerobic conditions and also in sufficient quantities. The cultures were also able to cometabolically degrade PCE to Ethylene. The isolated microorganisms can be used for remediation of DNAPL contaminated sites by in-situ biosurfactant production.

Albino, J. D.; Nambi, I. M.

2009-12-01

333

Yield and quality of ground water from stratified-drift aquifers, Taunton River basin, Massachusetts : executive summary  

USGS Publications Warehouse

Water shortages are a chronic problem in parts of the Taunton River basin and are caused by a combination of factors. Water use in this part of the Boston metropolitan area is likely to increase during the next decade. The Massachusetts Division of Water Resources projects that about 50% of the cities and towns within and on the perimeter of the basin may have water supply deficits by 1990 if water management projects are not pursued throughout the 1980s. Estimates of the long-term yield of the 26 regional aquifers indicate that the yields of the two most productive aquifers equal or exceed 11.9 and 11.3 cu ft/sec, 90% of the time, respectively, if minimum stream discharge is maintained at 99.5% flow duration. Eighteen of the 26 aquifers were pumped for public water supply during 1983. Further analysis of the yield characteristics of these 18 aquifers indicates that the 1983 pumping rate of each of these 18 aquifers can be sustained at least 70% of the time. Selected physical properties and concentrations of major chemical constituents in groundwater from the stratified-drift aquifers at 80 sampling sites were used to characterize general water quality in aquifers throughout the basin. The pH of the groundwater ranged from 5.4 to 7.0. Natural elevated concentrations of Fe and Mn in water in the stratified-drift aquifers are present locally in the basin. Natural concentrations of these two metals commonly exceed the limits of 0.3 mg/L for Fe and 0.05 mg/L for Mn recommended for drinking water. Fifty-one analyses of selected trace metals in groundwater samples from stratified-drift aquifers throughout the basin were used to characterize trace metal concentrations in the groundwater. Of the 10 constituents sampled that have US EPA limits recommended for drinking water, only the Pb concentration in water at one site (60 micrograms/L) exceeded the recommended limit of 50 micrograms/L. Analyses of selected organic compounds in water in the stratified-drift aquifers at 74 locations revealed that 13 of the sample contained one or more of the following compounds: chloroform; carbon tetrachloride; dichloroethane; dichloroethylene; tetrachloroethylene; and, toluene. (Lantz-PTT)

Lapham, Wayne W.; Olimpio, Julio C.

1989-01-01

334

Ground-Water Levels and Water-Quality Data for Wells in the Crumpton Creek Area near Arnold Air Force Base, Tennessee, November 2001 to January 2002  

USGS Publications Warehouse

From November 2001 to January 2002, a study of the ground-water resources in the Crumpton Creek area of Middle Tennessee was conducted to determine whether volatile organic compounds (VOCs) from Arnold Air Force Base (AAFB) have affected local private water supplies and to advance understanding of the ground-water-flow system in this area. VOC samples were collected from private wells that were not included in previous sampling efforts conducted in the Crumpton Creek area near AAFB. Ground-water-flow directions were investigated by measuring water levels in wells and constructing a potentiometric-surface map of the Manchester aquifer in the study area. Data were collected from a total of 68 private wells, 82 monitoring wells, and 1 cave during the period of study. Ground-water levels were determined for 42 of the private wells and for all 82 monitoring wells. Of the 82 monitoring wells, 81 withdraw water from the Manchester aquifer and 1 well withdraws water from the overlying shallow aquifer. The Manchester aquifer wells range in depth from 20 to 150 feet. Water-level altitudes for the Manchester aquifer ranged from 956 to 1,064 feet above the National Geodetic Vertical Datum of 1929. Water levels ranged from approximately 6 feet above land surface to 94 feet below land surface. Water-quality samples were collected from all 68 private wells, 8 of the monitoring wells, and the 1 cave. Of the 55 VOCs analyzed, 42 were not detected. Thirteen VOCs were detected; however, only tetrachloroethylene (PCE), methylene chloride, and toluene were detected at concentrations equal to or above reporting levels for the analytical method used. PCE was detected in water samples from 15 private wells and was the only VOC that exceeded drinking water maximum contaminant levels for public water systems. PCE concentrations in samples from five of the wells were below the reporting level and ranged from estimated concentrations of 0.46 to 0.80 microgram per liter (?g/L). Samples from 10 wells contained concentrations equal to or greater than the analytical reporting level of 1 ?g/L for PCE. Samples from one of these wells contained PCE concentrations (12 ?g/L and 11 ?g/L) exceeding the drinking water maximum contaminant level of 5 ?g/L for PCE. The spatial distribution of PCE detections and the relative concentrations of PCE and trichloroethylene suggest that the PCE detections are associated with a small and localized ground-water contamination plume unrelated to AAFB ground-water contamination.

Williams, Shannon D.

2003-01-01

335

Interpretation of Borehole Geophysical Logs, Aquifer-Isolation Tests, and Water-Quality Data for Sites 1, 3, and 5 at the Willow Grove Naval Air Station/Joint Reserve Base, Horsham Township, Montgomery County, Pennsylvania: 2005  

USGS Publications Warehouse

Borehole geophysical logging, heatpulse-flowmeter measurements, borehole television surveys, and aquifer-isolation tests were conducted in 2005 at the Willow Grove Naval Air Station/Joint Reserve Base (NAS/JRB) in Horsham Township, Montgomery County, Pa. This study was done by the U.S. Geological Survey (USGS) in cooperation with the U.S. Navy in support of hydrogeological investigations to address ground-water contamination. Data collected for this study are valuable for understanding ground-water flow in the Stockton Formation at the local and regional scale. The Willow Grove NAS/JRB is underlain by the Stockton Formation, which consists of sedimentary rocks of Triassic age. The rocks of the Stockton Formation form a complex, heterogeneous aquifer with partially connected zones of high permeability. Borehole geophysical logs, heatpulse-flowmeter measurements, and borehole television surveys made in seven boreholes ranging from 70 to 350 ft deep were used to identify potential water-producing fractures and fracture zones and to select intervals for aquifer-isolation tests. An upward vertical hydraulic gradient was measured in one borehole, a downward vertical hydraulic gradient was measured in four boreholes, both an upward and a downward vertical hydraulic gradient were measured in one borehole, and no flow was measurable in one borehole. The aquifer-isolation tests isolated 30 discrete fractures in the seven boreholes for collection of depth-discrete hydraulic and water-quality data. Of the 30 fractures identified as potentially water producing, 26 fractures (87 percent) produced more than 1 gallon per minute of water. The specific capacity of the isolated intervals producing more than 1 gallon per minute ranged from 0.02 to 5.2 gallons per minute per foot. There was no relation between specific capacity and depth of the fracture. Samples for analysis for volatile organic compounds were collected from each isolated zone. Tetrachloroethylene (PCE) was the most prevalent compound at Site 1; concentrations were as great as 62 ?g/L (micrograms per liter). 1,1-dichloroethane was the most prevalent compound at Site 3; concentrations were as great as 9.3 ?g/L. Toluene was the most prevalent compound at Site 5; concentrations were as great as 77 ?g/L. For five out of the six wells (83 percent) sampled for field determinations of water-quality constituents, the interval with the lowest dissolved oxygen concentration had the highest total VOC concentration.

Sloto, Ronald A.

2007-01-01

336

Ground-water-quality assessment of shallow aquifers in the Front Range Urban Corridor, Colorado, 1954-98  

USGS Publications Warehouse

Historical (1954-98) water-quality data for major ions, trace elements, major plant nutrients, and organic constituents collected in 3,870 sampling events at 2,138 shallow wells represent ground-water quality in shallow aquifers that underlie the Front Range Urban Corridor in Colorado. Nonparametric summary statistics and maps of concentrations across the study area indicate that ground water in the study area included fresh to saline water. Sulfate concentrations were elevated in the north and northeast parts of the study area, possibly due to Pierre Shale and Laramie Formation shale outcrops in those areas. Apart from isolated areas of known contamination, chloride concentrations were generally less than 100 milligrams per liter across the study area. Wells with elevated nitrate concentrations usually were located near rivers and streams downgradient from metropolitan areas. Elevated nitrate concentrations in wells that were not along the South Platte River were possibly from individual sewage disposal system usage or from fertilizer application to land. Spatial distribution for organic compounds for which more than 40 percent of the data were above the detection limit (atrazine, methyl-tert-butylether, and prometon) is not widespread across the study area, but this may reflect limitations of data availability. Summary statistics calculated or estimated by decade are influenced by the temporal variability of data across the study area. The median values of specific conductance, chloride, and nitrate from the 1970?s are less than values from the 1980?s and 1990?s, which, because most samples from the l970?s were collected in the western part of the study area, indicates that water quality in the western part of the study area is generally different than the rest of the study area. Chloride may be introduced to ground water from runoff of road deicers or chlorinated organics in transportation/transitional areas, where the median concentration is the greatest (85.0 milligrams per liter). Nitrate median concentrations are several times greater where the land is cultivated or used for agricultural business, which may reflect use of nitrogen fertilizers and the presence of animal feeding operations. Most inorganic and organic constituents exceeded drinking-water standards in only a small percentage of samples. Exceptions to this include sulfate; nitrate; trace elements aluminum, cadmium, iron, and manganese; and organic compounds 1,1-dichloroethylene, tetrachloroethylene, trichloroethylene, benzene, and dichloromethane.

Flynn, Jennifer L.

2003-01-01

337

Effect of Clay Fraction on Hydraulic Properties and DNAPL Distribution in Porous Media  

NASA Astrophysics Data System (ADS)

Clays affect the hydraulic properties of natural porous media and commonly occur in all types of sedimentary deposits. Clay minerals and aggregates of clay minerals less than 2 microns in size are unique sediments that have physical and chemical properties much different than their silt and sand-sized counterparts. Even small amounts of clay have been observed to significantly impact the microscopic and macroscopic characteristics of porous media such as the effective porosity, pore-size distribution and permeability. These characteristics are important in determining aqueous and non-aqueous phase contaminant distribution and migration in the subsurface. The objectives of this research were to: determine and compare permeability, porosity and pore-size distribution in sandy porous media with and without clay; investigate the effect of clay on dense non-aqueous phase liquid (DNAPL) / water interfacial tension; and compare the differences in DNAPL distribution and movement within porous media with and without clay. Permeability and pore-size distribution were compared for porous media comprising well-sorted Ottawa white sand without a clay fraction (S), sand with 10 percent kaolinite by dry weight (K10) and sand with 10 percent Ca-montmorillonite by dry weight (M10) packed to the same total porosity. The permeability of K10 was an order-of-magnitude lower than S and the permeability of M10 was nearly three orders-of-magnitude lower than S. Tetrachloroethylene (PCE) / water pressure-saturation relationships were determined using pressure cells and differences in the PCE entry pressure of S and K10 were not statistically significant. Significant differences were measured in M10 as compared to S and K10. The pore-size distribution index, l, was highest in S, lower in K10 and lowest in M10 as expected. S and K10 appeared to reach a residual water saturation at capillary pressures less than 300 mbar while M10 did not. Micromodel visualization of sand-clay mixtures allowed the direct observation of clay distribution within a sand matrix in K10 and M10 porous media. Overall, the results of this research were useful in enhancing our understanding of the effect of clays in porous media.

Rossman, A. J.; Hayden, N. J.; Matmon, D.

2001-12-01

338

Development and reactivity of novel heterogeneous catalysts for hydrocarbon conversions  

SciTech Connect

Preparation of the novel solid acid catalyst AlCl[sub 2](SG)[sub n] has been accomplished in a sealed tube vapor deposition processed. Excessively dry silica is deficient in surface silanol (Si-OH) moieties such that effective reaction of Al[sub 2]Cl[sub 6] is not achieved. Exposure to humic air is sufficient to hydrate the silica to a level where the active catalyst can be prepared. The activity of AlCl[sub 2](SG)[sub n] in a number of acid-catalyzed reactions has been studied. In the alkylation of benzene and toluene, the catalyst was active in batch reactions but gives poor selectivity at elevated temperature in a flow reactor. The isomerization of butane and hexane have been examined. Cracking of hydrocarbon polymers as a possible recycling procedure is promising with AlCl[sub 2](SG)[sub n]. At 100[degrees]C in a batch reactor the activity of the catalyst for cracking polymers is comparable to that observed with n-hexadecane. Catalysts comprised of metal oxides dispersed on porous carbons are very effective in the oxidative decomposition of halogenated hydrocarbons at 250[degrees]C in air. Methylene chloride, 1,2-dichloroethane, 1,2,4-trichlorobenzene, tetrachloroethylene, tetrachloroethane and carbon tetrachloride are decomposed to CO[sub 2], CO and HCl over the carbon catalysts with high selectivity to HCl for the chlorinated products. A determining factor in the activity of the catalysts appears to be the micropore volume of the carbon support. The presence of water in the reaction mixture has no effect on the activity of the carbon catalysts. Reactions comparing CH[sub 2]Cl[sub 2] with CD[sub 2]Cl[sub 2] indicate a rate dependence on cleavage of a carbon-hydrogen bond. Kinetic studies in the methylene chloride experiment show a first order dependence on CH[sub 2]Cl[sub 2] concentration and an activation energy of 11.0 kcal/mol.

Petrosius, S.C.

1992-01-01

339

Induced Polarization with Electromagnetic Coupling: 3D Spectral Imaging Theory, EMSP Project No. 73836  

SciTech Connect

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.

Morgan, F. Dale; Sogade, John

2004-12-14

340

Use of Mathematical Models in the Design and Performance Evaluation of a Surfactant Flushing Demonstration at the Bachman Road Site  

NASA Astrophysics Data System (ADS)

This presentation provides an overview of the design and performance evaluation of a surfactant enhanced remediation pilot demonstration conducted in the summer of 2000 at a former dry cleaning facility in Oscoda, Michigan, USA. The unconfined contaminated formation is composed of relatively homogeneous glacial outwash sands, underlain by a thick clay layer. Core samples have revealed the presence of a reasonably persistent coarse sand and gravel layer at a depth of 11-16 feet and a sand/silt/clay transition zone at the base of the aquifer. A narrow tetrachloroethylene (PCE) plume emanates from the suspected source area, beneath the former dry cleaning building, and discharges into Lake Huron, approximately 700 feet down gradient. There is little evidence of microbial plume attenuation at the site. Aqueous samples from multilevel piezometers installed beneath the building have confirmed the presence of residual PCE within the coarse sand and gravel layer and have detected consistently high PCE concentrations at the base of the aquifer. The actual distribution and volume of entrapped PCE, however, is unknown. A surfactant injection and recovery scheme was designed and implemented to effectively flush the identified source area beneath the building. In this scheme, a line of water injection wells was installed behind the surfactant injection points to control surfactant delivery and maximize solubilized plume capture. Prior to surfactant injection, conservative and partitioning tracer tests were also conducted to confirm sweep and estimate source zone mass. Mass recovery calculations indicate that more than 94% of the injected surfactant and approximately 19 liters of PCE were recovered during the test. This volume of DNAPL is consistent with estimated low saturations within the swept zone. Single and multiphase transport models were employed to aid in remedial design and predict system performance. For the model simulations, input parameters were determined from batch and column experiments conducted with aquifer materials and fluids collected from the site. Model hydraulic conductivity distributions were generated using geostatistical methods, in conjunction with available grain size data from core samples. Model predictions of surfactant breakthrough and PCE solubilization are compared to measurements from the multilevel sampling points within the source zone. Discrepancies between predicted and actual test performance are identified and discussed.

Abriola, L. M.; Drummond, C. D.; Lemke, L. D.; Rathfelder, K. M.; Pennell, K. D.

2001-05-01

341

GE/NOMADICS IN-WELL MONITORING SYSTEM FOR VERTICAL PROFILING OF DNAPL CONTAMINANTS  

SciTech Connect

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.

Ronald E. Shaffer; Radislav Potyralio; Joseph Salvo; Timothy Sivavec; Lloyd Salsman

2003-04-01

342

Simultaneous determination of bisphenol A and bisphenol B in beverages and powdered infant formula by dispersive liquid-liquid micro-extraction and heart-cutting multidimensional gas chromatography-mass spectrometry.  

PubMed

The purpose of this study was to establish a reliable, cost-effective, fast and simple method to quantify simultaneously both bisphenol A (BPA) and bisphenol B (BPB) in liquid food matrixes such as canned beverages (soft drinks and beers) and powdered infant formula using dispersive liquid-liquid micro-extraction (DLLME) with in-situ derivatisation coupled with heart-cutting gas chromatography-mass spectrometry (GC-MS). For the optimisation of the DLLME procedure different amounts of various extractive and dispersive solvents as well as different amounts of the derivative reagent were compared for their effects on extraction efficiency and yields. The optimised procedure consisted of the injection of a mixture containing tetrachloroethylene (extractant), acetonitrile (dispersant) and acetic anhydride (derivatising reagent) directly into an aliquot of beverage samples or into an aqueous extract of powdered milk samples obtained after a pretreatment of the samples. Given the compatibility of the solvents used, and the low volumes involved, the procedure was easily associated with GC-MS end-point determination, which was accomplished by means of an accurate GC dual column (heart-cutting) technique. Careful optimisation of heart-cutting GC-MS conditions, namely pressure of front and auxiliary inlets, have resulted in a good analytical performance. The linearity of the matrix-matched calibration curves was acceptable, with coefficients of determination (r2) always higher than 0.99. Average recoveries of the BPA and BPB spiked at two concentration levels into beverages and powdered infant formula ranged from 68% to 114% and the relative standard deviation (RSD) was <15%. The limits of detection (LOD) in canned beverages were 5.0 and 2.0 ng l(-1) for BPA and BPB, respectively, whereas LOD in powdered infant formula were 60.0 and 30.0 ng l(-1), respectively. The limits of quantification (LOQ) in canned beverages were 10.0 and 7.0 ng l-1 for BPA and BPB, respectively, whereas LOQ in powdered infant formula were 200.0 and 100.0 ng l(-1), respectively. BPA was detected in 21 of 30 canned beverages (ranging from 0.03 to 4.70 µg l(-1)) and in two of seven powdered infant formula samples (0.23 and 0.40 µg l(-1)) collected in Portugal. BPB was only detected in canned beverages being positive in 15 of 30 samples analysed (ranging from 0.06 to 0.17 µg l(-1)). This is the first report about the presence of BPA and BPB in canned beverages and powdered infant formula in the Portuguese market. PMID:21240700

Cunha, S C; Almeida, C; Mendes, E; Fernandes, J O

2011-02-17

343

Hydrogen-bonding induced alternate stacking of donor (D) and acceptor (A) chromophores and their supramolecular switching to segregated states.  

PubMed

This paper reports comprehensive studies on the mixed assembly of bis-(trialkoxybenzamide)-functionalized dialkoxynaphthalene (DAN) donors and naphthalene-diimide (NDI) acceptors due the cooperative effects of hydrogen bonding, charge-transfer (CT) interactions, and solvophobic effects. A series of DAN as well as NDI building blocks have been examined (wherein the relative distance between the two amide groups in a particular chromophore is the variable structural parameter) to understand the structure-dependent variation in mode of supramolecular assembly and morphology (organogel, reverse vesicle, etc.) of the self-assembled material. Interestingly, it was observed that when the amide functionalities are introduced to enhance the self-assembly propensity, the mode of co-assembly among the DAN and NDI chromophores no longer remained trivial and was dictated by a relatively stronger hydrogen-bonding interaction instead of a weak CT interaction. Consequently, in a highly non-polar solvent like methylcyclohexane (MCH), although kinetically controlled CT-gelation was initially noticed, within a few hours the system sacrificed the CT-interaction and switched over to the more stable self-sorted gel to maximize the gain in enthalpy from the hydrogen-bonding interaction. In contrast, in a relatively less non-polar solvent such as tetrachloroethylene (TCE), in which the strength of hydrogen bonding is inherently weak, the contribution of the CT interaction also had to be accounted for along with hydrogen bonding leading to a stable CT-state in the gel or solution phase. The stability and morphology of the CT complex and rate of supramolecular switching (from CT to segregated state) were found to be greatly influenced by subtle structural variation of the building blocks, solvent polarity, and the DAN/NDI ratio. For example, in a given D-A pair, by introducing just one methylene unit in the spacer segment of either of the building blocks a complete change in the mode of co-assembly (CT state or segregated state) and the morphology (1D fiber to 2D reverse vesicle) was observed. The role of solvent polarity, structural variation, and D/A ratio on the nature of co-assembly, morphology, and the unprecedented supramolecular-switching phenomenon have been studied by detail spectroscopic and microscopic experiments in a gel as well as in the solution state and are well supported by DFT calculations. PMID:22782621

Das, Anindita; Molla, Mijanur Rahaman; Maity, Bholanath; Koley, Debasis; Ghosh, Suhrit

2012-07-10

344

Probabilistic performance-assessment modeling of the mixed waste landfill at Sandia National Laboratories.  

SciTech Connect

A probabilistic performance assessment has been conducted to evaluate the fate and transport of radionuclides (americium-241, cesium-137, cobalt-60, plutonium-238, plutonium-239, radium-226, radon-222, strontium-90, thorium-232, tritium, uranium-238), heavy metals (lead and cadmium), and volatile organic compounds (VOCs) at the Mixed Waste Landfill (MWL). Probabilistic analyses were performed to quantify uncertainties inherent in the system and models for a 1,000-year period, and sensitivity analyses were performed to identify parameters and processes that were most important to the simulated performance metrics. Comparisons between simulated results and measured values at the MWL were made to gain confidence in the models and perform calibrations when data were available. In addition, long-term monitoring requirements and triggers were recommended based on the results of the quantified uncertainty and sensitivity analyses. At least one-hundred realizations were simulated for each scenario defined in the performance assessment. Conservative values and assumptions were used to define values and distributions of uncertain input parameters when site data were not available. Results showed that exposure to tritium via the air pathway exceeded the regulatory metric of 10 mrem/year in about 2% of the simulated realizations when the receptor was located at the MWL (continuously exposed to the air directly above the MWL). Simulations showed that peak radon gas fluxes exceeded the design standard of 20 pCi/m{sup 2}/s in about 3% of the realizations if up to 1% of the containers of sealed radium-226 sources were assumed to completely degrade in the future. If up to 100% of the containers of radium-226 sources were assumed to completely degrade, 30% of the realizations yielded radon surface fluxes that exceeded the design standard. For the groundwater pathway, simulations showed that none of the radionuclides or heavy metals (lead and cadmium) reached the groundwater during the 1,000-year evaluation period. Tetrachloroethylene (PCE) was used as a proxy for other VOCs because of its mobility and potential to exceed maximum contaminant levels in the groundwater relative to other VOCs. Simulations showed that PCE reached the groundwater, but only 1% of the realizations yielded aquifer concentrations that exceeded the regulatory metric of 5 {micro}g/L. Based on these results, monitoring triggers have been proposed for the air, surface soil, vadose zone, and groundwater at the MWL. Specific triggers include numerical thresholds for radon concentrations in the air, tritium concentrations in surface soil, infiltration through the vadose zone, and uranium and select VOC concentrations in groundwater. The proposed triggers are based on U.S. Environmental Protection Agency and Department of Energy regulatory standards. If a trigger is exceeded, then a trigger evaluation process will be initiated which will allow sufficient data to be collected to assess trends and recommend corrective actions, if necessary.

Peace, Gerald L.; Goering, Timothy James (GRAM, Inc.); Miller, Mark Laverne; Ho, Clifford Kuofei

2005-11-01

345

Geohydrology and simulation of ground-water flow in the Red Clay Creek Basin, Chester County, Pennsylvania, and New Castle County, Delaware  

USGS Publications Warehouse

The 54-square-mile Red Clay Creek Basin, located in the lower Delaware River Basin, is underlain primarily by metamorphic rocks that range from Precambrian to Lower Paleozoic in age. Ground water flows through secondary openings in fractured crystalline rock and through primary openings below the water table in the overlying saprolite. Secondary porosity and permeability vary with hydrogeologic unit, topographic setting, and depth. Thirty-nine percent of the water-bearing zones are encountered within 100 feet of the land surface, and 79 percent are within 200 feet. The fractured crystalline rock and overlying saprolite act as a single aquifer under unconfined conditions. The water table is a subdued replica of the land surface. Local ground-water flow systems predominate in the basin, and natural ground-water discharge is to streams, comprising 62 to 71 percent of streamflow. Water budgets for 1988-90 for the 45-square-mile effective drainage area above the Woodale, Del., streamflow-measurement station show that annual precipitation ranged from 43.59 to 59.14 inches and averaged 49.81 inches, annual streamflow ranged from 15.35 to 26.33 inches and averaged 20.24 inches, and annual evapotranspiration ranged from 27.87 to 30.43 inches and averaged 28.98 inches. The crystalline rocks of the Red Clay Creek Basin were simulated two-dimensionally as a single aquifer under unconfined conditions. The model was calibrated for short-term steady-state conditions on November 2, 1990. Recharge was 8.32 inches per year. Values of aquifer hydraulic conductivity in hillside topographic settings ranged from 0.07 to 2.60 feet per day. Values of streambed hydraulic conductivity ranged from 0.08 to 26.0 feet per day. Prior to simulations where ground-water development was increased, the calibrated steady-state model was modified to approximate long-term average conditions in the basin. Base flow of 11.98 inches per year and a ground-water evapotranspiration rate of 2.17 inches per year were simulated by the model. Different combinations of ground-water supply and wastewater-disposal plans were simulated to assess their effects on the stream-aquifer system. Six of the simulations represent an increase in population of 14,283 and water use of 1.07 million gallons per day. One simulation represents an increase in population of 28,566 and water use of 2.14 million gallons per day. Reduction of average base flow is greatest for development plans with wastewater removed from the basin through sewers and is proportional to the amount of water removed from the basin. The development plan that had the least effect on water levels and base flow included on-lot wells and on-lot septic systems. Five organochlorine insecticides--lindane, DDT, dieldrin, heptachlor, and methoxychlor--were detected in ground water. Four organophosphorus insecticides--malathion, parathion, diazinon, and phorate--were detected in ground water. Four volatile organic compounds--benzene, toluene, tetrachloroethylene, and trichloroethylene--were detected in ground water. Phenol was detected at concentrations up to 8 micrograms per liter in water from 50 percent of 14 wells sampled. The concentration of dissolved nitrate in water from 18 percent of wells sampled exceeded 10 milligrams per liter as nitrogen; concentration of nitrate were as high as 19 milligrams per liter. PCB was detected in the bottom material of West Branch Red Clay Creek at Kennet Square at concentrations up to 5,600 micrograms per kilogram.

Vogel, K. L.; Reif, A. G.

1993-01-01

346

Quality of shallow ground water in areas of recent residential and commercial development, Wichita, Kansas, 2000  

USGS Publications Warehouse

Water samples from 30 randomly distributed monitoring wells in areas of recent residential and commercial development (1960-96), Wichita, Kansas, were collected in 2000 as part of the High Plains Regional Ground-Water Study conducted by the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. The samples were analyzed for about 170 water-quality constituents that included chlorofluorocarbons, physical properties, dissolved solids and major ions, nutrients and dissolved organic carbon, trace elements, pesticide compounds, and volatile organic compounds. The purpose of this report is to provide an assessment of water quality in recharge to shallow ground water underlying areas of recent residential and commercial development and to determine the relation of ground-water quality to overlying urban land use. Analyses of water from the 30 monitoring wells for chlorofluorocarbons were used to estimate apparent dates of recharge. Water from 18 wells with nondegraded and uncontaminated chlorofluorocarbon concentrations had calculated apparent recharge dates that ranged from 1979 to 1990 with an average date of 1986. Water from 14 monitoring wells (47 percent) exceeded the 500-milligrams-per-liter Secondary Maximum Contaminant Level established by the U.S. Environmental Protection Agency for dissolved solids in drinking water. The Secondary Maximum Contaminant Levels of 250 milligrams per liter for chloride and sulfate were exceeded in water from one well. The source of the largest concentrations of dissolved solids and associated ions, such as chloride and sulfate, in shallow ground water in the study area probably is highly mineralized water moving out of the Arkansas River into the adjacent, unconsolidated deposits and mixing with the dominant calcium bicarbonate water in the deposits. Concentrations of most nutrients in water from the sampled wells were small, with the exception of nitrate. Although water from the sampled wells did not have nitrate concentrations larger than the 10-milligram-per-liter Maximum Contaminant Level for drinking water, water from 50 percent of the sampled wells showed nitrate enrichment (concentrations greater than 2.0 milligrams per liter). Most trace elements in water from the sampled wells were detected only in small concentrations, and few exceeded respective water-quality standards. Twenty percent of iron concentrations, 40 percent of manganese concentrations, 3 percent of arsenic concentrations, and 13 percent of uranium concentrations exceeded respective Maximum Contaminant Levels or Secondary Maximum Contaminant Levels. A total of 47 pesticide compounds were analyzed in ground-water samples during this study. Water from 73 percent of the wells sampled had detectable concentrations of one or more of 8 of these 47 compounds. The herbicide atrazine or its degradation product deethylatrazine were detected most frequently (in water from 70 percent of the sampled wells). Metolachlor was detected in water from 10 percent of the wells, and simazine was detected in water from 30 percent of the wells sampled. Other pesticides detected included dieldrin, pendimethalin, prometon, and tebuthiuron (each in water from 3 percent of the wells). All concentrations of these compounds were less than established Maximum Contaminant Levels. A total of 85 volatile organic compounds (VOCs) were analyzed in ground-water samples during this study. Water from 43 percent of the wells had a detectable concentration of one or more VOCs. Chloroform was the most frequently detected VOC (23 percent of the wells sampled).Seven other VOCs were detected in water at frequencies of 13 percent or less in the wells sampled. Concentrations of VOCs were less than respective Maximum Contaminant Levels, except one sample with a concentration of 9.0 micrograms per liter for tetrachloroethylene (Maximum Contaminant Level of 5.0 micrograms per liter). An analysis of hydraulic gradient, flow velocity

Pope, Larry M.; Bruce, Breton W.; Rasmussen, Patrick P.; Milligan, Chad R.

2002-01-01

347

Water-Quality Conditions of Chester Creek, Anchorage, Alaska, 1998-2001  

USGS Publications Warehouse

Between October 1998 and September 2001, the U.S. Geological Survey's National Water-Quality Assessment Program evaluated the water-quality conditions of Chester Creek, a stream draining forest and urban settings in Anchorage, Alaska. Data collection included water, streambed sediments, lakebed sediments, and aquatic organisms samples from urban sites along the stream. Urban land use ranged from less than 1 percent of the basin above the furthest upstream site to 46 percent above the most downstream site. Findings suggest that water quality of Chester Creek declines in the downstream direction and as urbanization in the watershed increases. Water samples were collected monthly and during storms at a site near the stream's mouth (Chester Creek at Arctic Boulevard) and analyzed for major ions and nutrients. Water samples collected during water year 1999 were analyzed for selected pesticides and volatile organic compounds. Concentrations of fecal-indicator bacteria were determined monthly during calendar year 2000. During winter, spring, and summer, four water samples were collected at a site upstream of urban development (South Branch of South Fork Chester Creek at Tank Trail) and five from an intermediate site (South Branch of South Fork Chester Creek at Boniface Parkway). Concentrations of calcium, magnesium, sodium, chloride, and sulfate in water increased in the downstream direction. Nitrate concentrations were similar at the three sites and all were less than the drinking-water standard. About one-quarter of the samples from the Arctic Boulevard site had concentrations of phosphorus that exceeded the U.S. Environmental Protection Agency (USEPA) guideline for preventing nuisance plant growth. Water samples collected at the Arctic Boulevard site contained concentrations of the insecticide carbaryl that exceeded the guideline for protecting aquatic life. Every water sample revealed a low concentration of volatile organic compounds, including benzene, toluene, tetrachloroethylene, methyl tert-butyl ether, and chloroform. No water samples contained volatile organic compounds concentrations that exceeded any USEPA drinking-water standard or guideline. Fecal-indicator bacteria concentrations in water from the Arctic Boulevard site commonly exceeded Federal and State guidelines for water-contact recreation. Concentrations of cadmium, copper, lead, and zinc in streambed sediments increased in the downstream direction. Some concentrations of arsenic, chromium, lead, and zinc in sediments were at levels that can adversely affect aquatic organisms. Analysis of sediment chemistry in successive lakebed-sediment layers from Westchester Lagoon near the stream's mouth provided a record of water-quality trends since about 1970. Concentrations of lead have decreased from peak levels in the mid-1970s, most likely because of removing lead from gasoline and lower lead content in other products. However, concen-trations in recently-deposited lakebed sediments are still about 10 times greater than measured in streambed sediments at the upstream Tank Trail site. Zinc concentrations in lakebed sediments also increased in the early 1970s to levels that exceeded guidelines to protect aquatic life and have remained at elevated but variable levels. Pyrene, benz[a]anthracene, and phenanthrene in lakebed sediments also have varied in concentrations and have exceeded protection guidelines for aquatic life since the 1970s. Concentrations of dichloro-diphenyl-trichloroethane, polychlorinated biphenyls (PCBs), or their by-products generally were highest in lakebed sediments deposited in the 1970s. More recent sediments have concentrations that vary widely and do not show distinct temporal trends. Tissue samples of whole slimy sculpin (Cottus cognatus), a non-migratory species of fish, showed con-centrations of trace elements and organic contaminants. Of the constituents analyzed, only selenium concentra-tions showed levels of potential concern for

Glass, Roy L.; Ourso, Robert T.

2006-01-01

348

Interpretation of borehole geophysical logs, aquifer-isolation tests, and water quality, supply wells 1 and 2, Willow Grove Naval Air Station/Joint Reserve Base, Horsham Township, Montgomery County, Pennsylvania  

USGS Publications Warehouse

Ground water pumped from supply wells 1 and 2 on the Willow Grove Naval Air Station/Joint Reserve Base (NAS/JRB) provides water for use at the base, including potable water for drinking. The supply wells have been contaminated by volatile organic compounds (VOC?s), particularly trichloroethylene (TCE) and tetrachloroethylene (PCE), and the water is treated to remove the VOC?s. The Willow Grove NAS/JRB and surrounding area are underlain by sedimentary rocks of the Triassic-age Stockton Formation, which form a complex, heterogeneous aquifer. The ground-water-flow system for the supply wells was characterized by use of borehole geophysical logs and heatpulse-flowmeter measurements. The heatpulse-flowmeter measurements showed upward and downward borehole flow under nonpumping conditions in both wells. The hydraulic and chemical properties of discrete water-bearing fractures in the supply wells were characterized by isolating each water-bearing fracture with straddle packers. Eight fractures in supply well 1 and five fractures in supply well 2 were selected for testing on the basis of the borehole geophysical logs and borehole television surveys. Water samples were collected from each isolated fracture and analyzed for VOC?s and inorganic constituents. Fractures at 50?59, 79?80, 196, 124?152, 182, 241, 256, and 350?354 ft btoc (feet below top of casing) were isolated in supply well 1. Specific capacities ranged from 0.26 to 5.7 (gal/min)/ft (gallons per minute per foot) of drawdown. The highest specific capacity was for the fracture isolated at 179.8?188 ft btoc. Specific capacity and depth of fracture were not related in either supply well. The highest concentrations of PCE were in water samples collected from fractures isolated at 236.8?245 and 249.8?258 ft btoc, which are hydraulically connected. The concentration of PCE generally increased with depth to a maximum of 39 mg/L (micrograms per liter) at a depth of 249.8? 258 ft btoc and then decreased to 21 mg/L at a depth of 345.3?389 ft btoc. Fractures at 68?74, 115, 162, 182, 205, and 314 ft btoc were isolated in supply well 2. Specific capacities ranged from 0.08 to less than 2.9 (gal/ min)/ft. The highest specific capacity was for the fracture isolated at 157?165.2 ft btoc. Concentrations of detected VOC?s in water samples were 3.6 mg/L or less. Lithologic units penetrated by both supply wells were determined by correlating naturalgamma and single-point-resistance borehole geophysical logs. All lithologic units are not continuous water-bearing units because water-bearing fractures are not necessarily present in the same lithologic units in each well. Although the wells penetrate the same lithologic units, the lithologic location of only three water-bearing fractures are common to both wells. The same lithologic unit may have different hydraulic properties in each well. A regional ground-water divide is southeast of the supply wells. From this divide, ground water flows northwest toward Park Creek, a tributary to Little Neshaminy Creek. Potentiometric-surface maps were prepared from water levels measured in shallow and deep wells. For both depth intervals, the direction of ground-water flow is toward the northwest. For most well clusters, the vertical head gradient is downward from the shallow to the deeper part of the aquifer. Pumping of the supply wells at times can cause the vertical flow direction to reverse.

Sloto, Ronald A.; Goode, Daniel J.; Frasch, Steven M.

2002-01-01

349

Ground-Water Quality Data in the Monterey Bay and Salinas Valley Basins, California, 2005 - Results from the California GAMA Program  

USGS Publications Warehouse

Ground-water quality in the approximately 1,000-square-mile Monterey Bay and Salinas Valley study unit was investigated from July through October 2005 as part of the California Ground-Water Ambient Monitoring and Assessment (GAMA) program. The study was designed to provide a spatially unbiased assessment of raw ground-water quality, as well as a statistically consistent basis for comparing water quality throughout California. Samples were collected from 94 public-supply wells and 3 monitoring wells in Monterey, Santa Cruz, and San Luis Obispo Counties. Ninety-one of the public-supply wells sampled were selected to provide a spatially distributed, randomized monitoring network for statistical representation of the study area. Six wells were sampled to evaluate changes in water chemistry: three wells along a ground-water flow path were sampled to evaluate lateral changes, and three wells at discrete depths from land surface were sampled to evaluate changes in water chemistry with depth from land surface. The ground-water samples were analyzed for volatile organic compounds (VOCs), pesticides, pesticide degradates, nutrients, major and minor ions, trace elements, radioactivity, microbial indicators, and dissolved noble gases (the last in collaboration with Lawrence Livermore National Laboratory). Naturally occurring isotopes (tritium, carbon-14, helium-4, and the isotopic composition of oxygen and hydrogen) also were measured to help identify the source and age of the sampled ground water. In total, 270 constituents and water-quality indicators were investigated for this study. This study did not attempt to evaluate the quality of water delivered to consumers; after withdrawal from the ground, water typically is treated, disinfected, and (or) blended with other waters to maintain water quality. In addition, regulatory thresholds apply to treated water that is served to the consumer, not to raw ground water. In this study, only six constituents, alpha radioactivity, N-nitrosodimethylamine, 1,2,3-trichloropropane, nitrate, radon-222, and coliform bacteria were detected at concentrations higher than health-based regulatory thresholds. Six constituents, including total dissolved solids, hexavalent chromium, iron, manganese, molybdenum, and sulfate were detected at concentrations above levels set for aesthetic concerns. One-third of the randomized wells sampled for the Monterey Bay and Salinas Valley GAMA study had at least a single detection of a VOC or gasoline additive. Twenty-eight of the 88 VOCs and gasoline additives investigated were found in ground-water samples; however, detected concentrations were one-third to one-sixty-thousandth of their respective regulatory thresholds. Compounds detected in 10 percent or more of the wells sampled include chloroform, a compound resulting from the chlorination of water, and tetrachloroethylene (PCE), a common solvent. Pesticides and pesticide degradates also were detected in one-third of the ground-water samples collected; however, detected concentrations were one-thirtieth to one-fourteen-thousandth of their respective regulatory thresholds. Ten of the 122 pesticides and pesticide degradates investigated were found in ground-water samples. Compounds detected in 10 percent or more of the wells sampled include the herbicide simazine, and the pesticide degradate deethylatrazine. Ground-water samples had a median total dissolved solids (TDS) concentration of 467 milligrams per liter (mg/L), and 16 of the 34 samples had TDS concentrations above the recommended secondary maximum contaminant level (SMCL-a threshold established for aesthetic qualities: taste, odor, and color) of 500 mg/L, while four samples had concentrations above the upper SMCL of 1,000 mg/L. Concentrations of nitrate plus nitrite ranged from 0.04 to 37.8 mg/L (as nitrogen), and two samples had concentrations above the health-based threshold for nitrate of 10 mg/L (as nitrogen). The median sulfate concentration

Kulongoski, Justin T.; Belitz, Kenneth

2007-01-01

350

Modeling of a supersonic DC plasma torch system for carbon nanotube production  

NASA Astrophysics Data System (ADS)

The carbon nanotube (CNT) structure forms a very promising source material. It has unique properties such as high thermal and electrical conductivities, and a very high mechanical strength. In recent years, researchers were able to improve both the quantity and quality of the CNT production. Among the efforts made to scale up the production, Harbec and Meunier designed a new plasma torch process for the industrial production of CNT in bulk powder form. Their process is based on the DC plasma-jet pyrolysis of a carbon-containing gas. Experiments were conducted using either 100 slpm of argon or 225 slpm of helium. Tetrachloroethylene (C2Cl4, or TCE) was selected as the carbon raw material. The present work focuses on the modeling of this CNT synthesis process and aims at an understanding of the physical and chemical phenomena observed in this system. First, a description is made of the temperature and flow fields, as well as the species concentration distribution in the torch nozzle using both possibilities of He or Ar as the plasma gas. This is followed in the second part of the thesis by a model aimed to study the nucleation and evolution of the metal particles acting as catalyst for CNT growth in the nozzle. In the third part, the modeling of the TCE pyrolysis process in the flow was carried out. The fluid dynamics equations are used in this system showing supersonic characteristics. A realizable k-? model is used to address the turbulent effects in the flow fields. The moment method is employed to calculate the formation of the fine catalyst particles from the metal vapor injected. Within the supersonic domain of the flow field, the influence of existing shock waves on the particle nucleation is discussed, as well as the chemical reactions involved. Results show that the supersonic phenomena make it possible for metal particles to nucleate and be maintained in small sizes. This however also causes a backflow in the nozzle, which partially contributes to the experimentally observed soot deposition and CNT growth within the nozzle. The carbon containing gas experiences a fast dissociation process once it enters the nozzle. The produced carbon species are maintained in small clusters of carbon atoms in the high temperature environment within the nozzle. These clusters and atoms serve as the source of CNT growth and form a layer of carbon deposit on the surface of the nozzle. This deposited layer acts as a thermal insulator changing the conditions in the nozzle, particularly on the wall. A modeling of this effect is performed, confirming that the basic requirements for CNT growth are attained within the nozzle itself. A parametric study of the process is carried out and suggestions are made on the geometry of the reactor and the operating parameters for the formation of CNT. These modeling results suggest that the process can be optimized with carefully chosen operating parameters. With the specific design of the nozzle used here, it is recommended to operate at lower pressures in the reactor in order to avoid a backflow in the nozzle. Different kinds of metal catalyst can be used in this system and the reactor length should be adjusted accordingly in order to optimize the outcome of the process.

Guo, Liping

351

Hanford Site Groundwater Monitoring for Fiscal Year 1998  

SciTech Connect

This report presents the results of groundwater and vadose-zone monitoring and remediation for fiscal year (FY) 1998 on the Word Site, Washington. Soil-vapor extraction in the 200-West Area removed 777 kg of carbon tetrachloride in FY 1998, for a total of 75,490 kg removed since remediation began in 1992. Spectral gamma logging and evaluation of historical gross gamma logs near tank farms and liquid-disposal sites in the 200 Areas provided information on movement of contaminants in the vadose zone. Water-level monitoring was performed to evaluate groundwater-flow directions, to track changes in water levels, and to relate such changes to evolving disposal practices. Water levels over most of the Hanford Site continued to decline between June 1997 and June 1998. The most widespread radiological contaminant plumes in groundwater were tritium and iodine-129. Concentrations of technetium-99, uranium, strontium-90, and carbon-14 also exceeded drinking water standards in smaller plumes. Plutonium and cesium-137 exceeded standards only near the 216-B-5 injection well. Derived concentration guide levels specified in U.S. Department of Energy Order 5400.5 were exceeded for tritium, uranium, strontium-90, and plutonium in small plumes or single wells. One well completed in the basalt-confined aquifer beneath the 200-East Area exceeded the drinking water standard for technetium-99. Nitrate is the most extensive chemical contaminant. Carbon tetrachloride, chloroform, chromium, cis-l, Z-dichloroethylene, fluoride, and trichloroethylene also were present in smaller areas at levels above their maximum contaminant levels. Cyanide concentrations were elevated in one area but were below the maximum contaminant level. Tetrachloroethylene exceeded its maximum contaminant level in several wells in the 300 Area for the first time since the 1980s. Metals such as aluminum, cadmium, iron, manganese, and nickel exceeded their maximum contaminant levels in filtered samples from numerous wells; they are believed to represent natural components of groundwater. Resource Conservation and Recovery Act of 1976 groundwater monitoring continued at 25 waste management areas during FY 1998: 17 under detection programs and data indicate that they are not adversely affecting groundwater, 6 under interim-status groundwater-quality-assessment programs to assess possible contamination, and 2 under final-status corrective-action programs. Groundwater remediation in the 100 Areas continued to reduce the amount of strontium-90 (100-N) and chromium (100-K, D, and H) reaching the Columbia River. Two systems in the 200-West Area operated to prevent the spread of carbon tetrachloride and technetide uranium plumes. Groundwater monitoring continued at these sites and at other sites where there is no active remediation. A three-dimensional, numerical groundwater model was applied to simulate radionuclide movement from sources in the 200 Areas following site closure in 2050. Contaminants will continue to move toward the southeast and north (through Gable Gap), but the areas with levels exceeding drinking water standards will diminish.

Hartman, M.J. [and others

1999-03-24

352

ATR-FTIR sensor development for continuous on-line monitoring of chlorinated aliphatic hydrocarbons in a fixed-bed bioreactor.  

PubMed

This article describes the continuous on-line monitoring of a dechlorination process by a novel attenuated total reflection-Fourier transform infrared (ATR-FTIR) sensor. This optical sensor was developed to measure noninvasively part-per-million (ppm) concentrations of trichloroethylene (TCE), tetrachloroethylene (PCE), and carbon tetrachloride (CT) in the aqueous effluent of a fixed-bed dechlorinating bioreactor, without any prior sample preparation. The sensor was based on an ATR internal reflection element (IRE) coated with an extracting hydrophobic polymer, which prevented water molecules from interacting with the infrared (IR) radiation. The selective diffusion of chlorinated compound molecules from aqueous solution into the polymer made possible their detection by the IR beam. With the exclusion of water the detection limits were lowered, and measurements in the low ppm level became possible. The best extracting polymer was polyisobutylene (PIB) in the form of a 5.8-microm thick film, which afforded a detection limit of 2, 3, and 2. 5 mg/L (ppm) for TCE, PCE, and CT, respectively. Values of the enrichment factors between the polymer coating and the water matrix of these chloro-organics were determined experimentally and were compared individually with predictions obtained from the slopes of absorbance/concentration curves for the three analytes. Before coupling the ATR-FTIR sensor to the dechlorinating bioreactor, preliminary spectra of the chlorinated compounds were acquired on a laboratory scale configuration in stop-flow and flow-through closed-loop modes. In this way, it was possible to study the behavior and direct response of the optical sensor to any arbitrary concentration change of the analytes. Subsequently, the bioreactor was monitored with the infrared sensor coupled permanently to it. The sensor tracked the progression of the analytes' spectra over time without perturbing the dechlorinating process. To calibrate the ATR-FTIR sensor, a total of 13 standard mixtures of TCE, PCE and CT at concentrations ranging from 0 to 60 ppm were selected according to a closed symmetrical experimental design derived from a 3(2) full-factorial design. The above range of concentrations chosen for calibration reflected typical values during normal bioreactor operation. Several partial least squares (PLS) calibration models were generated to resolve overlapping absorption bands. The standard error of prediction (SEP) ranged between 0.6 and 1 ppm, with a relative standard error of prediction (RSEP) between 3 and 6% for the three analytes. The accuracy of this ATR-FTIR sensor was checked against gas chromatography (GC) measurements of the chlorocompounds in the bioreactor effluents. The results demonstrate the efficiency of this new sensor for routine continuous on-line monitoring of the dechlorinating bioreactor. This strategy is promising for bioprocess control and optimization. PMID:10797233

Acha, V; Meurens, M; Naveau, H; Agathos, S N

2000-06-01

353

Hydrogeologic Investigation, Water Chemistry Analysis, and Model Delineation of contributing Areas for City of Tallahassee Public-Supply Wells, Tallahassee, Florida  

USGS Publications Warehouse

Ground water from the Upper Floridan aquifer is the sole source of water supply for Tallahassee, Florida, and the surrounding area. The City of Tallahassee (the City) currently operates 28 water-supply wells; 26 wells are distributed throughout the City and 2 are located in Woodville, Florida. Most of these wells yield an ample supply of potable water; however, water from several wells has low levels of tetrachloroethylene (PCE). The City removes the PCE from the water by passing it through granular-activated carbon units before distribution. To ensure that water-supply wells presently free of contamination remain clean, it is necessary to understand the ground-water flow system in sufficient detail to protect the contributing areas. Ground-water samples collected from four public-supply wells were analyzed for tritium (3H), chlorofluorocarbons (CFCs), and sulfur hexafluoride (SF6). Using data for the CFC compounds, apparent ground-water ages ranged from 7 to 31 years. For SF6, the apparent ages tended to be about 5 to 10 years younger than those from CFCs. Apparent ages based on the tritium/tritiogenic helium-3 (3H/3Hetrit) method ranged from 26 to 33 years. The three dating methods indicate that the apparent age of ground water generally decreases from northern to southern Leon County. This southward trend of decreasing ages is consistent with increasing amounts of recharge that occur as ground water moves from north to south. The ground-water age data derived by geochemical and tracer analyses were used in combination with the flow model and particle tracking to determine an effective porosity for the Hawthorn clays and Upper Floridan aquifer. The effective porosities for the Upper Floridan aquifer that resulted in best model matches were averaged to produce an effective porosity of 7 percent, and the effective porosities for the Hawthorn clays that resulted in a match were averaged to produce an effective porosity of 22 percent. Probabilistic contributing areas were determined for 26 City wells using MODFLOW and MODPATH. For each probabilistic contributing area delineated, the model was run 100 times and the results were analyzed statistically. For each of the 100 runs, a different hydraulic conductivity for each of the zones was assigned to the Upper Floridan aquifer. The hydraulic conductivities were generated randomly assuming a lognormal probability distribution; the mean of the distribution was equal to the hydraulic conductivity from the calibrated model. The 5-year time-dependent capture zones (TDCZs), assuming effective porosities of 0.1, 1, and 7 percent for four representative wells, were delineated. The higher probabilities of capture (greater than 40, 60, and 80 percent) were similar for all effective porosities, and the TDCZ delineated using a 7-percent porosity was slightly smaller; the lower probabilities of capture (greater than 10 and 20 percent) showed a large range of variability.

Davis, J. Hal; Katz, Brian G.

2007-01-01

354

Results of the basewide monitoring program at Wright-Patterson Air Force Base, Ohio, 1993-1994  

USGS Publications Warehouse

Geologic and hydrologic data were collected at Wright-Patterson Air Force Base (WPAFB), Ohio, as part of Basewide Monitoring Program (BMP) that began in 1992. The BMP was designed as a long-term project to character ground-water and surface-water quality (including streambed sediments), describe water-quality changes as water enters, flows across, and exits the Base, and investigate the effects of activities at WPAFB on regional water quality. Ground water, surface ware, and streambed sediment were sampled in four rounds between August 1993 and September 1994 to provide the analytical data needed to address the objectives of the BMP. Surface-water-sampling rounds were designed to include most of the seasonal hydrologic conditions encountered in southwestern Ohio, including baseflow conditions and spring runoff. Ground-water-sampling rounds were scheduled for times of recession and recharfe. Ground-water data were used to construct water-table, potentiometric, and vertical gradient maps of the WPAFB area. Water levels have not changed significantly since 1987, but the effects of pumping on and near the Base can have a marked effect on water levels in localized areas. Ground-ware gradients generally were downward throughout Area B (the southwestern third of the Base) and in the eastern third of Areas A and C (the northeastern two-thirds of the Base), and were upward in the vicinity of Mad River. Stream-discharge measurements verified these gradients. Many of the U.S. Environmental Protection Agency maximum contaminant level (MCL) exceedances of inorganic constituents in ground water were associated with water from the bedrock. Exceedances of concentrations of chromium and nickel were found consistently in five wells completed in the glacial aquifer beneath the Base. Five organic compounds [trichloroethylene (TCE), tetrachloroethylene (PCE), vinyl chloride, benzene, and bis(2-ethylhexyl) phthalate] were detected at concentrations that exceeded MCLs; all of the TCE, PCE, and vinyl chloride exceedances were in water from glacial aquifer, whereas the benzene exceedance and most of the bis(2-ethylhexyl) phthalate exceedances were in water from the bedrock. TCE (16 exceedances) and PCE (11 exceedances) most frequently exceeded the MCLs and were detected in the most samples. A decrease in concentrations of inorganic and organic compounds with depth suggest that many constituents detected in ground-water samples are associated partly with human activities, in addition to their natural occurrence. Included in the list of these constituents are nickel, chromium, copper, lead vanadium, zinc, bromide, and nitrate. Many constituents are not found at depths greater than 60 to 80 feet, possibly indicating that human effects on ground-water quality are limited to shallow flow systems. Organic compounds detected in shallow or intermediate-depth wells were aligned mostly with flowpaths that pass through or near identified hazardous-waste sites. Few organic contaminants were detected in surface water. The only organic compound to exceed MCLs for drinking water was bis(2-ethylhexyl) phthalate, but it was detected at concentrations just above the MCL. Inorganic constituents detected at concentration exceeding MCLs include beryllium (twice), lead (once), thallium (once), and gross alpha radiation (once). No polycyclic aromatic (PAHs) were detected in surface-water samples. The highest concentrations of contaminants detected during a storm event were in samples from upgradient locations, indicating that off-Base sources may contribute to surface-water contamination. Inorganic and organic contaminants were found in streambed sediments at WPAFB, primarily in Areas A and C. Trace metals such as lead, mercury, arsenic, and cadmium were detected at 16 locations at concentrations considered 'elevated' according to a ranking scheme for sediments. PAHS were the organic compounds detected most frequently and in highest concentrations organo

Schalk, C. W.; Cunningham, W. L.

1996-01-01

355

Groundwater contamination and risk assessment of industrial complex in Busan Metropolitan City, Korea  

NASA Astrophysics Data System (ADS)

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).

Hamm, S.-Y.; Ryu, S. M.; Cheong, J.-Y.; Woo, Y.-J.

2003-04-01

356

Final report on the safety assessment of Trichloroethane.  

PubMed

Trichloroethane functions in cosmetics as a solvent. Although Trichloroethane has been reported to the Food and Drug Administration (FDA) to be used in cosmetic products, an industry survey found that it is not in current use in the cosmetic industry. Trichloroethane is considered a Class I ozone-depleting substance by the Environmental Protection Agency (EPA) and its use is prohibited in the United States, unless considered essential. The FDA has stated that Trichloroethane's use in cosmetics is considered nonessential. Trichloroethane is detected by gas chromatography, gas chromatography-mass spectrometry, and gas-liquid chromatography. In rats, Trichloroethane, whether inhaled or injected, is mostly expelled intact from the body through exhalation. A very small percentage is excreted in the urine. In humans, Trichloroethane is rapidly absorbed through the skin and eliminated in exhaled air and a very small percentage is excreted in urine. Inhaled Trichloroethane is eliminated in exhaled air. Acute oral LD(50) values have been reported as follows: 12.3 g/kg in male rats; 10.3 g/kg in female rats; 11.24 g/kg in female mice; 5.66 g/kg in female rabbits; and 9.47 g/kg in male guinea pigs. Acute toxicity studies using other routes of exposure, including subcutaneous injection and inhalation, produced no evidence of significant toxicity, except at very high exposure levels. Continuous inhalation exposure of rabbits to 750 mg/m(3) for 90 days did not produce any signs of toxicity. Continuous exposure of rats, guinea pigs, rabbits, and monkeys to 500 ppm Trichloroethane for 6 months did not produce any signs of toxicity. Other short-term and subchronic inhalation exposures confirmed acute and short-term exposure findings that the toxic effects of inhalation were a function of both concentration and time. Rats receiving 750 or 1500 mg/kg day(- 1) Trichloroethane in corn oil by oral gavage 5 days per week for 78 weeks had reduced body weights and early mortality. Reduced body weights, decreased survival rates, and early mortality (in females) were found in mice dosed with 3000 or 6000 mg/kg day(- 1) (over the last 58 weeks; lower doses were administered for the first 20 weeks). Mice exposed to prolonged periods of Trichloroethane in an inhalation chamber had increased motor activity at levels up to 5000 ppm. Further increase of concentration of exposure resulted in less of an increase of motor activity until motor activity began to fall below normal at 10,000 ppm. Adverse effects on motor activity in rats were seen at exposures as low as 3000 ppm for 4 h. Rabbits had slight reddening and scaling after 10 24-h applications to abdominal skin of Trichloroethane mixed with 2.4% to 3.0% dioxane, and slight to moderate erythema, slight edema, and slight exfoliation was observed when 75% Trichloroethane and 25% tetrachloroethylene were applied to rabbit ears for 11 days. Undiluted Trichloroethane applied to the clipped backs of guinea pigs produced histopathologic damage in the epidermis. A primary irritation index of 5.22 (out of 8) was reported in rabbits. Trichloroethane applied to the eyes of rabbits resulted in transient irritation and apparent pain, but no corneal damage. There was no effect on gestation, pup survival, or growth in mice given Trichloroethane in drinking water at up to 5.83 mg/ml during mating and/or gestation. Rats exhibited no or minimal effects of ingestion of Trichloroethane up to 30 ppm in drinking water during mating and/or gestation. There was no effect on gestation, pup survival, or growth in mice or rats inhaling 875 ppm Trichloroethane. However, prenatal exposure of rodents to Trichloroethane can produce developmental toxicity in the form of delayed development in the offspring. Trichloroethane has been found to be mutagenic in the Ames assay in some studies and not mutagenic in others. Trichloroethane induced transformations in Fischer rat embryo cell system at 99 mu M, was not mutagenic using the mouse lymphoma assay at up to 0.51 mu g/ml, was equivocal in that assay when tested with S9, and was also

2008-01-01

357

Reactive hydro- end chlorocarbons in the troposphere and lower stratosphere : sources, distributions, and chemical impact  

NASA Astrophysics Data System (ADS)

The work presented in this thesis focuses on measurements of chemical reactive C2 C7 non-methane hydrocarbons (NMHC) and C1 C2 chlorocarbons with atmospheric lifetimes of a few hours up to about a year. The group of reactive chlorocarbons includes the most abundant atmospheric species with large natural sources, which are chloromethane (CH3Cl), dichloromethane (CH2Cl2), and trichloromethane (CHCl3), and tetrachloroethylene (C2Cl4) with mainly anthropogenic sources. The NMHC and chlorocarbons are present at relatively low quantities in our atmosphere (10-12 10-9 mol mol-1 of air). Nevertheless, they play a key role in atmospheric photochemistry. For example, the oxidation of NMHC plays a dominant role in the formation of ozone in the troposphere, while the photolysis of chlorocarbons contributes to enhanced ozone depletion in the stratosphere. In spite of their important role, however, their global source and sinks budgets are still poorly understood. Hence, this study aims at improving our understanding of the sources, distribution, and chemical role of reactive NMHC and chlorocarbons in the troposphere and lower stratosphere. To meet this aim, a comprehensive data set of selected C2 C7 NMHC and chlorocarbons has been analyzed, derived from six aircraft measurement campaigns with two different jet aircrafts (the Dutch TUD/NLR Cessna Citation PH-LAB, and the German DLR Falcon) conducted between 1995 and 2001 (STREAM 1995 and 1997 and 1998, LBA-CLAIRE 1998, INDOEX 1999, MINOS 2001). The NMHC and chlorocarbons have been detected by gas-chromatography (GC-FID/ECD) in pre-concentrated whole air samples collected in stainless steel canister on-board the measurement aircrafts. The measurement locations include tropical (Maldives/Indian Ocean and Surinam), midlatitude (Western Europe and Canada) and polar regions (Lapland/northern Sweden) between the equator to about 70ŗN, covering different seasons and pollution levels in the troposphere and lower stratosphere. Of special interest in this thesis are the tropical regions because they are becoming increasingly important in terms of global anthropogenic pollution and climate change. In addition, natural emissions of hydrocarbons (notably isoprene and terpenes from plants) and reactive chlorocarbons appear to be concentrated in the tropics, where the largest uncertainties exist with respect to source type and source strength. Whenever available, the reactive NMHC and chlorocarbon data have been analyzed with the help of concurrent measurements, which includes ozone (O3), carbon monoxide (CO), nitrogen oxide (NO), total reactive oxidized nitrogen (NOy), nitrous oxide (N2O), carbon dioxide (CO2), methane (CH4), acetone (CH3COCH3), methanol (CH3OH), acetonitrile (CH3CN), the chlorofluorocarbons CFC-11 (CCl3F) and CFC-12 (CCl2F2), the hydrofluorocarbon HFC-134a (CH2FCF3), and the hydrochlorofluorocarbons HCFC-141b (CH3CCl2F) and HCFC-142b (CH3CClF2). These additional measurements provided important information about the air mass origin, pollution sources, and chemical age of the encountered air masses. The STREAM-measurements contribute to the present understanding of the budgets of reactive organic trace species in the mid-latitude lower stratosphere at different seasonal conditions. It was found that during summer and fall, the mean concentrations of reactive NMHC and acetone in the lower stratosphere were a factor of two or more higher than during winter, as a result of more intense and frequent mixing across the tropopause. The role of tropical emissions in the global budget of hydrocarbons and the chlorocarbons CH3Cl, CH2Cl2, CHCl3, and C2Cl4 has been investigated during the LBA/CLAIRE 1998, INDOEX 1999 and MINOS 2001 campaigns. The INDOEX measurements over the Indian Ocean showed that strongly enhanced CH3Cl and related combustion tracers, such as CO, hydrocarbons and CH3CN in polluted air masses from India and Southeast Asia, relate to the extensive use of biofuels (notably the burning of agricultural waste and dung) in households and small industries. During the MINOS campaign

Scheeren, H. A.

2003-09-01