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1

Induction of rat liver drug-metabolizing enzymes by tetrachloroethylene  

Microsoft Academic Search

The effect of tetrachloroethylene on Phase I and II drug-metabolizing enzymes in rat liver was examined. Rats were treated orally with tetrachloroethylene daily for five days, at doses of 125, 250, 500, 1,000 and 2,000 mg\\/kg. The higher doses (>500 mg\\/kg) of tetrachloroethylene induced the hepatic microsomal 7-pentoxyresorufin O-depentylase and 7-benzyloxyresorufin O-debenzylase activities associated with the CYP2B subfamily. 7-ethoxyresorufin O-deethylase

N. Hanioka; H. Jinno; T. Toyo'oka; T. Nishimura; M. Ando

1995-01-01

2

40 CFR 721.3560 - Derivative of tetra-chloro-ethy-lene.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Derivative of tetra-chloro-ethy-lene. ...Chemical Substances § 721.3560 Derivative of tetra-chloro-ethy-lene. ...paragraph (a)(2) of this section: Derivative of tetrachloroethylene,...

2013-07-01

3

40 CFR 721.3560 - Derivative of tetra-chloro-ethy-lene.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Derivative of tetra-chloro-ethy-lene. ...Chemical Substances § 721.3560 Derivative of tetra-chloro-ethy-lene. ...paragraph (a)(2) of this section: Derivative of tetrachloroethylene,...

2012-07-01

4

Surfactant enhanced remediation of soil columns contaminated by residual tetrachloroethylene  

Microsoft Academic Search

The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting (14)C-labeled PCE into water-saturated soil columns and displacing the free product with water. Miscible displacement experiments were conducted before and after PCE entrapment to determine the influence or residual PCE on column dispersivities. The

K. D. Pennell; M. Jin; L. M. Abriola; G. A. Pope

1994-01-01

5

Human Health Effects of Tetrachloroethylene: Key Findings and Scientific Issues  

PubMed Central

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

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

2014-01-01

6

Surfactant enhanced remediation of soil columns contaminated by residual tetrachloroethylene  

SciTech Connect

The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting (14)C-labeled PCE into water-saturated soil columns and displacing the free product with water. Miscible displacement experiments were conducted before and after PCE entrapment to determine the influence or residual PCE on column dispersivities. The first two column studies involved the injection of a 4% solution of polyoxyethylene (POE) (20) sorbitan monooleate, resulting in the removal of 90% and 97% of the residual PCE from 20-30- and 40-120-mesh Ottawa sand, respectively. Although micellar solubilization of PCE was the primary mode of recovery in these experiments, this process was shown to be rate-limited.

Pennell, K.D.; Jin, M.; Abriola, L.M.; Pope, G.A.

1994-01-01

7

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

EPA Science Inventory

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

8

Behavioral effects of trichloroethylene and tetrachloroethylene in mice.  

PubMed

This study was performed to clarify the toxicological profiles of trichloroethylene (TRCE) and tetrachloroethylene (TECE) when they are administered intraperitoneally in mice. The ED50 for loss of righting reflex were 2596 mg/kg in TRCE and 4209 mg/kg in TECE. TRCE and TECE impaired bridge test performance at 500 and 2000 mg/kg, respectively. An operant behavior performance was also inhibited by TRCE at 1000 mg/kg and by TECE at 2000 mg/kg. Both TRCE and TECE exhibited anticonflict effects in a Vogel-type task at 500 mg/kg. This effect was confirmed by the finding that TRCE exhibited anticonflict action in a Geller-type paradigm at 250 mg/kg and more, as did TRCE did at 1000 mg/kg. These results show that TRCE and TECE affect various behaviors in mice and suggest that conflict behaviors are one of the most sensitive behavioral indicators of the effects of these substances. The toxicological profiles of TRCE and TECE with respect to behavioral effects were very similar, and they can be classified in a single category. PMID:9329056

Umezu, T; Yonemoto, J; Soma, Y; Miura, T

1997-11-01

9

Surfactant enhanced remediation of soil columns contaminated by residual tetrachloroethylene  

NASA Astrophysics Data System (ADS)

The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting 14C-labeled PCE into water-saturated soil columns and displacing the free product with water. Miscible displacement experiments were conducted before and after PCE entrapment to determine the influence of residual PCE on column dispersivities. The first two column studies involved the injection of a 4% solution of polyoxyethylene (POE) ( 20) sorbitan monooleate, resulting in the removal of 90% and 97% of the residual PCE from 20-30- and 40-120-mesh Ottawa sand, respectively. Although micellar solubilization of PCE was the primary mode of recovery in these experiments, this process was shown to be rate-limited based on: (a) the disparity between initial steady-state concentrations of PCE in the column effluent and equilibrium values measured in batch experiments; and (b) the increase in effluent concentrations of PCE following periods of flow interruption. In the latter two experiments, surfactant solutions containing mixtures of sodium sulfosuccinates removed >99% of the residual PCE from soil columns packed with 40-270-mesh Ottawa sand. Approximately 80% of the PCE was mobilized as a separate organic liquid after lushing with < 100 mL of these surfactant solutions. This study demonstrates the capacity of surfactant flushing to enhance the recovery of residual PCE from Ottawa sand and indicates that ultra-low interfacial tensins (<0.001 dyn cm -1) are not required to achieve significant PCE mobilization when buoyancy forces are important. The potential for displacement of dense nonaqueousphase liquids as a separate organic phase should, therefore, be evaluated during the selection of surfactant formulations for aquifer remediation.

Pennell, Kurt D.; Jin, Minquan; Abriola, Linda M.; Pope, Gary A.

1994-05-01

10

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

11

Prenatal Exposure to Tetrachloroethylene-Contaminated Drinking Water and the Risk of Adverse Birth Outcomes  

Microsoft Academic Search

Background: Prior studies of prenatal exposure to tetrachloroethylene (PCE) have shown mixed results regarding its effect on birth weight and gestational age. Objectives: In this retrospective cohort study we examined whether PCE contamination of public drinking-water supplies in Massachusetts influenced the birth weight and gestational duration of children whose mothers were exposed before the child's delivery. Methods: The study included

Ann Aschengrau; Janice Weinberg; Sarah Rogers; Lisa Gallagher; Michael Winter; Veronica Vieira; Thomas Webster; David Ozonoff

2008-01-01

12

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

13

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

14

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

SciTech Connect

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

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

2003-01-01

15

SURFACTANT ENHANCED RECOVERY OF TETRACHLOROETHYLENE FROM A POROUS MEDIUM CONTAINING LOW PERMEABILITY LENSES. 1. EXPERIMENTAL STUDIES. (R825409)  

EPA Science Inventory

Abstract A matrix of batch, column and two-dimensional (2-D) box experiments was conducted to investigate the coupled effects of rate-limited solubilization and layering on the entrapment and subsequent recovery of a representative dense NAPL, tetrachloroethylene (PCE)...

16

Reductive degradation of tetrachloroethylene by biogenic and chemogenic carbonate green rust  

NASA Astrophysics Data System (ADS)

Degradation of contaminants with microorganisms and natural soil minerals has been extensively studied for understanding of complex interaction mechanism in bio-geochemical reactions. In this study, we conducted a batch experiment to demonstrate the different degradation mechanism of tetrachloroethylene (PCE) in biogenic and chemogenic carbonate green rust suspensions. Both green rusts were characterized by measurement of Fe(II) content, BET, X-ray diffraction, and transmission electron spectroscopy before and after the reaction. The effects of mineral loading, initial concentration of PCE, and solution pH on the degradation kinetic of PCE were investigated. The concentration profiles of transformation products were also monitored to investigate the different degradation mechanism of PCE by biogenic and chemogenic green rust.

Lee, N.; Bae, S.; Lee, W.

2013-12-01

17

Tetrachloroethylene in Drinking Water and Birth Outcomes at the US Marine Corps Base at Camp Lejeune, North Carolina  

Microsoft Academic Search

A study of mean birth weight, small-for-gestational-age infants, and preterm birth was conducted at the US Marine Corps Base at Camp Lejeune, North Carolina, where drinking water was contaminated with volatile organic compounds. Tetrachloroethylene (PCE) was the predominant contaminant. The authors used multiple linear and logistic regression to analyze 1968-1985 data from 11,798 birth certificates. Overall, at most weak associations

N. Sonnenfeld; I. Hertz-Picciotto; W. E. Kaye

2001-01-01

18

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

19

Biotransformation of tetrachloroethylene to trichloroethylene, dichloroethylene, vinyl chloride, and carbon dioxide under methanogenic conditions.  

PubMed Central

Tetrachloroethylene (PCE) and trichloroethylene (TCE), common industrial solvents, are among the most frequent contaminants found in groundwater supplies. Due to the potential toxicity and carcinogenicity of chlorinated ethylenes, knowledge about their transformation potential is important in evaluating their environmental fate. The results of this study confirm that PCE can be transformed by reductive dehalogenation to TCE, dichloroethylene, and vinyl chloride (VC) under anaerobic conditions. In addition, [14C]PCE was at least partially mineralized to CO2. Mineralization of 24% of the PCE occurred in a continuous-flow fixed-film methanogenic column with a liquid detention time of 4 days. TCE was the major intermediate formed, but traces of dichloroethylene isomers and VC were also found. In other column studies under a different set of methanogenic conditions, nearly quantitative conversion of PCE to VC was found. These studies clearly demonstrate that TCE and VC are major intermediates in PCE biotransformation under anaerobic conditions and suggest that potential exists for the complete mineralization of PCE to CO2 in soil and aquifer systems and in biological treatment processes. PMID:3923927

Vogel, T M; McCarty, P L

1985-01-01

20

Integrating Address Geocoding, Land Use Regression, and Spatiotemporal Geostatistical Estimation for Groundwater Tetrachloroethylene  

PubMed Central

Geographic Information Systems (GIS) based techniques are cost-effective and efficient methods used by state agencies and epidemiology researchers for estimating concentration and exposure. However, budget limitations have made statewide assessments of contamination difficult, especially in groundwater media. Many studies have implemented address geocoding, land use regression, and geostatistics independently, but this is the first to examine the benefits of integrating these GIS techniques to address the need of statewide exposure assessments. A novel framework for concentration exposure is introduced that integrates address geocoding, land use regression (LUR), below detect data modeling, and Bayesian Maximum Entropy (BME). A LUR model was developed for Tetrachloroethylene that accounts for point sources and flow direction. We then integrate the LUR model into the BME method as a mean trend while also modeling below detects data as a truncated Gaussian probability distribution function. We increase available PCE data 4.7 times from previously available databases through multistage geocoding. The LUR model shows significant influence of dry cleaners at short ranges. The integration of the LUR model as mean trend in BME results in a 7.5% decrease in cross validation mean square error compared to BME with a constant mean trend. PMID:22264162

Messier, Kyle P.; Akita, Yasuyuki; Serre, Marc L.

2012-01-01

21

Integrating address geocoding, land use regression, and spatiotemporal geostatistical estimation for groundwater tetrachloroethylene.  

PubMed

Geographic information systems (GIS) based techniques are cost-effective and efficient methods used by state agencies and epidemiology researchers for estimating concentration and exposure. However, budget limitations have made statewide assessments of contamination difficult, especially in groundwater media. Many studies have implemented address geocoding, land use regression, and geostatistics independently, but this is the first to examine the benefits of integrating these GIS techniques to address the need of statewide exposure assessments. A novel framework for concentration exposure is introduced that integrates address geocoding, land use regression (LUR), below detect data modeling, and Bayesian Maximum Entropy (BME). A LUR model was developed for tetrachloroethylene that accounts for point sources and flow direction. We then integrate the LUR model into the BME method as a mean trend while also modeling below detects data as a truncated Gaussian probability distribution function. We increase available PCE data 4.7 times from previously available databases through multistage geocoding. The LUR model shows significant influence of dry cleaners at short ranges. The integration of the LUR model as mean trend in BME results in a 7.5% decrease in cross validation mean square error compared to BME with a constant mean trend. PMID:22264162

Messier, Kyle P; Akita, Yasuyuki; Serre, Marc L

2012-03-01

22

Identification of active agents for tetrachloroethylene degradation in Portland cement slurry containing ferrous iron.  

PubMed

Experimental studies were designed to identify the active agents in Fe(II)-based degradative solidification/stabilization (Fe(II)-DS/S) that are responsible for the degradation of tetrachloroethylene (PCE) as well as the conditions that enhance the formation of these active agents. First, the conditions that lead to maximizing production of the active agents were identified by measuring the ability of various chemical mixtures to degrade PCE. Results showed that Fe(II), Fe(III), and Cl were the elements most closely associated with high degradation rates. In addition to elemental composition, unknown factors associated with the formation of solid phases could also be important in determining the extent of formation of active reducing agents. Second, instrumental analysis techniques (XRD, SEM, SEM-EDS) were used to identify compounds in chemical mixtures that were observed to have high activities for PCE degradation. SEM-EDS analysis indicated that Fe was associated with hexagonal particles, which is the typical shape of several AFm phases in hydrated Portland cement that are composed of calcium, aluminum/iron, hydroxide, and possibly other anions. No Fe-containing solid phases could be identified. Therefore, it appears that AFm phases are the most likely active agents for PCE degradation in mixtures containing Portland cement or its acid extract. Mixtures without cement did not form the same solid phases but were observed to form ferrous hydroxide as a major solid phase. PMID:17874793

Ko, Saebom; Batchelor, Bill

2007-08-15

23

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

24

Kinetics of tetrachloroethylene-reductive dechlorination catalyzed by vitamin B{sub 12}  

SciTech Connect

Reductive dechlorination kinetics of tetrachloroethylene (PCE) to ethylene catalyzed by vitamin B{sub 12} using Ti[III] citrate as the bulk reductant was examined in a vapor-water batch system. A kinetic model incorporating substrate-B{sub 12} electron-transfer complex formation and subsequent product release was developed. The model also accounted for the primary reductive dechlorination pathways (hydrogenolysis and reductive {beta} elimination) and vapor/water-phase partitioning. Reaction rate constants were sequentially determined by fitting the model to experimental kinetic data while moving upward through consecutive reaction pathways. The release of product from the complex was found to be second order with respect to substrate concentration for both PCE and acetylene; all other substrates appeared to release by first order. Reductive {beta} elimination was found to be a significant reaction pathway for trichloroethylene (TCE), and chloroacetylene was observed as a reactive intermediate. Acetylene production appears to be primarily due to the reduction of chloroacetylene derived from TCE. The reduction of cis-dichloroethylene (cis-DCE), the primary DCE isomer formed, was extremely slow, leading to a significant buildup of cis-DCE. The kinetics of acetylene and vinyl chloride reduction appeared to be limited by the formation of relatively stable substrate-B{sub 12} complexes. The relatively simple model examined appears to adequately represent the main features of the experimental data.

Burris, D.R. [AFRL/MLQR, Tyndall AFB, FL (United States); Delcomyn, C.A. [Applied Research Associates, Inc., Tyndall AFB, FL (United States); Deng, B. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Mineral and Environmental Engineering; Buck, L.E. [Polytechnic Univ., Brooklyn, NY (United States). Dept. of Civil and Environmental Engineering; Hatfield, K. [Univ. of Florida, Gainesville, FL (United States). Dept. of Civil Engineering

1998-09-01

25

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

PubMed Central

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

2012-01-01

26

Lactate Injection by Electric Currents for Bioremediation of Tetrachloroethylene in Clay  

PubMed Central

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 cm2 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.

2012-01-01

27

Improving the extraction of tetrachloroethylene from soil columns using surfactant gradient systems  

NASA Astrophysics Data System (ADS)

In this work, we extend the recently developed gradient approach for surfactant-enhanced remediation of dense non-aqueous phase liquid (DNAPL)-impacted sites. The goal of the gradient approach is to maximize the DNAPL solubilization capacity in swollen micelles (Type I aqueous microemulsions) while at the same time minimizing the potential for DNAPL mobilization. In this work, we introduce a modified version of the capillary/trapping curve that we refer to as the gradient curve to help interpret and/or design the gradient approach. The gradient curve presents the residual DNAPL saturation as a function of interfacial tension and microemulsion viscosity. This approach demonstrates that keeping a low viscosity of the microemulsion phase is not only important for keeping a low head loss during surfactant flooding but also to prevent oil mobilization. Eight microemulsion systems were evaluated in this research; these systems were evaluated based on their tetrachloroethylene (PCE) solubilization capacity, interfacial tension (IFT), viscosity, density, and coalescence kinetics. Two of these systems were chosen for evaluation in site-specific column tests using an increasing electrolyte gradient to produce a decreasing IFT/increasing solubilization gradient system. The column studies were conducted with media from Dover Air Force Base in Dover, DE. Both solubilized and mobilized DNAPL were quantified. During the column studies, we observed that substantial PCE was mobilized when the residual level of PCE in the column was significantly higher than the steady-state residual saturation level being approach (as predicted from the gradient curve). Four column studies were performed, three of which were used to asses the validity of the gradient curve in predicting the residual saturation after each gradient step. From these tests we observed that starting IFTs of less than 1 mN/m all produced the same mobilization potential. In the last column, we used an additional gradient step with an initial IFT above 1 mN/m to dramatically reduce the amount of PCE mobilize. Based on the good agreement between column results and projections based on the gradient curve, we propose this as a preferred method for designing gradient surfactant flushing systems.

Childs, Jeffrey D.; Acosta, Edgar; Knox, Robert; Harwell, Jeffrey H.; Sabatini, David A.

2004-07-01

28

CONCENTRATION OF TETRACHLOROETHYLENE IN INDOOR AIR AT A FORMER DRY CLEANER FACILITY AS A FUNCTION OF SUBSURFACE CONTAMINATION: A CASE STUDY  

EPA Science Inventory

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

29

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

PubMed

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. PMID:12117642

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

2002-07-01

30

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

31

Impact of tetrachloroethylene-contaminated drinking water on the risk of breast cancer: Using a dose model to assess exposure in a case-control study  

Microsoft Academic Search

BACKGROUND: A population-based case-control study was undertaken in 1997 to investigate the association between tetrachloroethylene (PCE) exposure from public drinking water and breast cancer among permanent residents of the Cape Cod region of Massachusetts. PCE, a volatile organic chemical, leached from the vinyl lining of certain water distribution pipes into drinking water from the late 1960s through the early 1980s.

Verónica Vieira; Ann Aschengrau; David Ozonoff

2005-01-01

32

Spectroscopic signatures of VOC physisorption on microporous solids. Application for trichloroethylene and tetrachloroethylene adsorption on MFI zeolites.  

PubMed

This paper presents an experimental infrared spectroscopic study of the physisorption of trichloroethylene (TCE) and tetrachloroethylene (PCE) on a self-supported high silica ZSM5 zeolite. The evolution of the shape, area, and location of vibration bands of both the adsorbent and the adsorbate is analyzed with respect to the number of sorbed molecules. The state of the adsorbed phase is characterized upon adsorption by comparing the location of the investigated vibration bands with the location of the corresponding vibration bands of the chloroalkenes in gaseous, liquid, and solid phases. The singular behavior of PCE with respect to TCE is seen from the modification of vibration bands of both the adsorbed phase and the adsorbent upon loading. The adsorption process proceeds by stages for PCE, whereas it appears continuous for TCE. Particular micropore loadings are evidenced at 4 and 6.5 molec.uc(-1) for PCE and at 6 molec.uc(-1) for TCE, in agreement with previous macroscopic and microscopic data. In addition, the presence of admolecules induces at least one emerging vibration band located at around 1715 cm(-1), mainly due to a contribution of the microporous surface of the adsorbent. PMID:16852661

Bertrand, O; Weber, G; Maure, S; Bernardet, V; Bellat, J P; Paulin, C

2005-07-14

33

The effect of low concentrations of tetrachloroethylene on H2 adsorption and activation on Pt in a fuel cell catalyst  

NASA Astrophysics Data System (ADS)

The poisoning effect of tetrachloroethylene (TTCE) on the activity of a Pt fuel cell catalyst for the adsorption and activation of H2 was investigated at 60 °C and 2 atm using hydrogen surface concentration measurements. The impurity was chosen as a model compound for chlorinated cleaning and degreasing agents that may be introduced into a fuel cell as a contaminant at a fueling station and/or during vehicle maintenance. In the presence of only H2, introduction of up to 540 ppm TTCE in H2 to Pt/C resulted in a reduction of available Pt surface atoms (measured by H2 uptake) by ca. 30%, which was not enough to shift the H2-D2 exchange reaction away from being equilibrium limited. Exposure of TTCE to Pt/C in a mixed redox environment (hydrogen + oxygen), similar to that at the cathode of a fuel cell, resulted in a much more significant loss of Pt surface atom availability, suggesting a role in TTCE decomposition and/or Cl poisoning. Regeneration of catalyst activity of poisoned Pt/C showed the highest level of recovery when regenerated in only H2, with much less recovery in H2 + O2 or O2. The results from this study are in good agreement with those found in a fuel cell study by Martínez-Rodríguez et al. [2] and confirm that the majority of the poisoning from TTCE on fuel cell performance is most likely at the cathode, rather than the anode.

Zhang, Jack Z.; Colón-Mercado, Héctor R.; Goodwin, James G.

2011-10-01

34

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

1996-10-01

35

Spatiotemporal variability of tetrachloroethylene in residential indoor air due to vapor intrusion: a longitudinal, community-based study.  

PubMed

The migration of volatile contaminants from groundwater and soil into indoor air is a potential health threat at thousands of contaminated sites across the country. This phenomenon, known as vapor intrusion, is characterized by spatial and temporal heterogeneity. This study examined short-term fluctuations in concentrations of tetrachloroethylene (PCE) in the indoor air of residential homes due to vapor intrusion in a community in San Antonio, Texas, that sits atop an extensive, shallow plume of contaminated groundwater. Using a community-based design, we removed potential indoor sources of PCE and then collected twelve 3-day passive indoor air samples in each of the 20 homes. Results demonstrated a one-order-of-magnitude variability in concentration across both space and time among the study homes, although all measured concentrations were below risk-based screening levels. We found that within any given home, indoor concentrations increase with the magnitude of the barometric pressure drop (P=0.048) and humidity (P<0.001), while concentrations decrease as wind speed increases (P<0.001) and also during winter (P=0.001). In a second analysis to examine sources of spatial variability, we found that indoor air PCE concentrations between homes increase with groundwater concentration (P=0.030) and a slab-on-grade (as compared with a crawl space) foundation (P=0.028), whereas concentrations decrease in homes without air conditioners (P=0.015). This study offers insights into the drivers of temporal and spatial variability in vapor intrusion that can inform decisions regarding monitoring and exposure assessment at affected sites. PMID:23549403

Johnston, Jill E; Gibson, Jacqueline MacDonald

2014-11-01

36

Catalytic dehydrohalogenation and hydrogenation using H{sub 2} and palladium as a method for the removal of tetrachloroethylene from water  

SciTech Connect

The reduction of tetrachloroethylene to ethane in water by hydrogen and supported palladium was rapid at room temperature even at the low hydrogen partial pressure of 0.1 atm. The rate constant for reaction of PCE with 0.05g of 1% Pd on polyethylenimine coated beads was 0.034min{sup -1}. Ethane and ethene production were concomitant with ethane accounting for 65% of the initial PCE and ethene about 2%. When the support was alumina pellets, granular carbon, or activated carbon powder, PCE disappeared within 10 minutes and rate data could not obtained. Ethane was produced in these systems with yields of 65-80% while ethene was a reactive intermediate whose maximum amount was about 5% of the initial PCE. Particle size was important when using a carbon support. If hydrogen was added after PCE sorption onto the activated carbon powder, the amount of ethane formed was the same as when hydrogen was added initially. However, when hydrogen was added after PCE sorption onto granular carbon, less than 10% of the PCE could be accounted for as ethane.

Schreier, C.G.; Reinhard, M. [Stanford Univ., CA (United States)

1995-12-01

37

Risk of breast cancer following exposure to tetrachloroethylene-contaminated drinking water in Cape Cod, Massachusetts: reanalysis of a case-control study using a modified exposure assessment  

PubMed Central

Background Tetrachloroethylene (PCE) is an important occupational chemical used in metal degreasing and drycleaning and a prevalent drinking water contaminant. Exposure often occurs with other chemicals but it occurred alone in a pattern that reduced the likelihood of confounding in a unique scenario on Cape Cod, Massachusetts. We previously found a small to moderate increased risk of breast cancer among women with the highest exposures using a simple exposure model. We have taken advantage of technical improvements in publically available software to incorporate a more sophisticated determination of water flow and direction to see if previous results were robust to more accurate exposure assessment. Methods The current analysis used PCE exposure estimates generated with the addition of water distribution modeling software (EPANET 2.0) to test model assumptions, compare exposure distributions to prior methods, and re-examine the risk of breast cancer. In addition, we applied data smoothing to examine nonlinear relationships between breast cancer and exposure. We also compared a set of measured PCE concentrations in water samples collected in 1980 to modeled estimates. Results Thirty-nine percent of individuals considered unexposed in prior epidemiological analyses were considered exposed using the current method, but mostly at low exposure levels. As a result, the exposure distribution was shifted downward resulting in a lower value for the 90th percentile, the definition of "high exposure" in prior analyses. The current analyses confirmed a modest increase in the risk of breast cancer for women with high PCE exposure levels defined by either the 90th percentile (adjusted ORs 1.0-1.5 for 0-19 year latency assumptions) or smoothing analysis cut point (adjusted ORs 1.3-2.0 for 0-15 year latency assumptions). Current exposure estimates had a higher correlation with PCE concentrations in water samples (Spearman correlation coefficient = 0.65, p < 0.0001) than estimates generated using the prior method (0.54, p < 0.0001). Conclusions The incorporation of sophisticated flow estimates in the exposure assessment method shifted the PCE exposure distribution downward, but did not meaningfully affect the exposure ranking of subjects or the strength of the association with the risk of breast cancer found in earlier analyses. Thus, the current analyses show a slightly elevated breast cancer risk for highly exposed women, with strengthened exposure assessment and minimization of misclassification by using the latest technology. PMID:21600013

2011-01-01

38

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

PubMed Central

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

2012-01-01

39

Tetrachloroethylene Degradation by Dithionite with Ultraviolet Activation  

E-print Network

experiments (blank control, reagent control and UV control) were conducted to prove the feasibility of applying the dithionite/UV ARP to degrade PCE. ARP degradation of PCE was studied under different pH (5, 7, 8, 9) and light intensities (2, 4, 7.3 mW/cm2...

Zhang, Jingyuan

2013-07-30

40

Charge to the Tetrachloroethylene (Perchloroethylene) Neurotoxicity Expert Panel  

EPA Science Inventory

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

41

Hydrodechlorination of tetrachloroethylene over sulfided catalysts: kinetic study  

Microsoft Academic Search

In this work, a commercial sulfided hydrotreatment catalyst (2.8% NiO, 13.5% MoO3, supported on ?-alumina, supplied by Shell) is compared with different iron sulfide based catalysts. These catalysts were prepared from a by-product (called red mud (RM)) of the bauxite leaching in the Bayer process. Two different activation procedures were tested, both based in dissolving the RM in an acid

S. Ordóñez; F. V. D??ez; H. Sastre

2002-01-01

42

EVALUATION OF GEOPHYSICAL METHODS FOR THE DETECTION OF SUBSURFACE TETRACHLOROETHYLENE IN CONTROLLED SPILL EXPERIMENTS  

EPA Science Inventory

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), ...

43

SOLUBILIZATION OF DODECANE, TETRACHLOROETHYLENE, AND 1,2-DICHLOROBENZENE IN MICELLAR SOLUTIONS OF ETHOXYLATED NONIONIC SURFACTANTS  

EPA Science Inventory

Although surfactants have received considerable attention as a potential means for enhancing the recovery of organic compounds from the subsurface, only limited information is available regarding the micellar solubilization of common groundwater contaminants by nonionic surfactan...

44

Identification of active agents for tetrachloroethylene degradation in Portland cement slurry containing ferrous iron  

E-print Network

Fe(II)-based degradative solidification/stabilization (Fe(II)-DS/S) technology is the modification of conventional solidification/stabilization (S/S). Inorganic pollutants are immobilized by Fe(II)-DS/S while organic pollutants are destroyed...

Ko, Sae Bom

2006-08-16

45

A first French assessment of population exposure to tetrachloroethylene from small dry cleaning facilities  

E-print Network

carcinogenicity. In France, dry-cleaning facilities are integrated in urban environments (shopping malls. This exploratory work presents the results from five studies carried out in one shopping mall and four residential Adsorber (CA) and unfitted , with or without Air Exhaust System (AES). Samples were collected

Paris-Sud XI, Université de

46

[The effect of styrene and tetrachloroethylene on electrical activity of the retina].  

PubMed

Clinical investigations of ERG of 202 workers having a contact, during a process of production, with styrole and tetrachlorethylene vapours and of 50 workers having no such a contact as well as experimental investigations of ERG of isolated retina of a guinea-pig (n = 50) subjected to the action of these substances have shown that the action of styrole and tetrachlorethylene leads to a fall of electric activity of the retina. Functional changes develop both in photoreceptors and neuronal elements of the retina. These changes are directly proportional to the degree of styrole and tetrachlorethylene actions and can serve as an early sign of intoxication of the body. PMID:2531356

Mirzoev, T A; Sultanov, M Iu

1989-01-01

47

KINETICS OF THE TRANSFORMATION OF TRICHLOROETHYLENE AND TETRACHLOROETHYLENE BY IRON SULFIDE. (R825958)  

EPA Science Inventory

The transformation of nine halogenated aliphatic compounds by 10 g/L (0.5 m2/L) FeS at pH 8.3 was studied in batch experiments. These compounds were as follows: pentachloroethane (PCA), 1,1,2,2- and 1,1,1,2-tetrachloroethanes (1122-TeCA and 1112-TeCA), 1,1,...

48

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...

49

EVALUATION OF GEOPHYSICAL METHODS FOR THE DETECTION OF SUBSURFACE TETRACHLOROETHYLENE IN CONTROLLED SPILL EXPERIMENTS  

EPA Science Inventory

The purpose of the work was to determine the capability of various geophysical methods to detect PCE in the subsurface. Measurements were made with ten different geophysical techniques before, during, and after the PCE injection. This approach provided a clear identification of a...

50

Abstract Pseudomonas stutzeri OX1 naphthalene-oxi-dation activity is induced 3.0-fold by tetrachloroethylene  

E-print Network

, respectively, com- pared to the direct inducer of the pathway, o-cresol. Using P. putida PaW340 (pPP4062, p for 2-, 3-, and 4-chlorophenol, respec- tively (compared to an 8.8-fold induction with o-cresol

Wood, Thomas K.

51

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, ...

52

Laboratory and field investigation of chlorinated solvents remediation in soil and groundwater.  

E-print Network

??Chlorinated solvents are the second most ubiquitous contaminants, next to petroleum hydrocarbons, and many are carcinogens. Tetrachloroethylene or perchloroethene (PCE) has been employed extensively in… (more)

Santharam, Sathishkumar

2008-01-01

53

40 CFR Table 8 to Subpart Ffff of... - Partially Soluble Hazardous Air Pollutants  

...121697 45. Naphthalene 91203 46. Phosgene 75445 47. Propionaldehyde 123386 48. Propylene oxide 75569 49. Styrene 100425 50. Tetrachloroethylene (perchloroethylene) 127184 51. Tetrachloromethane (carbon tetrachloride)...

2014-07-01

54

40 CFR Table 8 to Subpart Ffff of... - Partially Soluble Hazardous Air Pollutants  

Code of Federal Regulations, 2012 CFR

...121697 45. Naphthalene 91203 46. Phosgene 75445 47. Propionaldehyde 123386 48. Propylene oxide 75569 49. Styrene 100425 50. Tetrachloroethylene (perchloroethylene) 127184 51. Tetrachloromethane (carbon tetrachloride)...

2012-07-01

55

40 CFR Table 7 to Subpart Hhhhh of... - Partially Soluble Hazardous Air Pollutants  

Code of Federal Regulations, 2011 CFR

...121697 46. Naphthalene 91203 47. Phosgene 75445 48. Propionaldehyde 123386 49. Propylene oxide 75569 50. Styrene 100425 51. Tetrachloroethylene (perchloroethylene) 127184 52. Tetrachloromethane (carbon tetrachloride)...

2011-07-01

56

ANAEROBIC BIOTRANSFORMATIONS OF POLLUTANT CHEMICALS IN AQUIFERS (JOURNAL VERSION)  

EPA Science Inventory

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 haloa...

57

EVALUATION OF HAZARDOUS WASTE INCINERATION IN AN AGGREGATE KILN: FLORIDA SOLITE CORPORATION  

EPA Science Inventory

Aggregate kiln incineration of chlorinated liquid organic waste was investigated in a one-week program at Florida Solite Company. POHCs (toluene, tetrachloroethylene, methyl ethyl ketone, and methyl isobutyl ketone) were monitored in waste and stack emissions. In addition, stack ...

58

BIOVENTING OF CHLORINATED SOLVENTS FOR GROUND-WATER CLEANUP THROUGH BIOREMEDIATION  

EPA Science Inventory

Chlorinated solvents such as tetrachloroethylene, trichloroethylene, carbon tetrachloride, chloroform, 1,2-dichloroethane, and dichloromethane (methylene chloride) can exist in contaminated subsurface material as (1) the neat oil, (2) a component of a mixed oily waste, (3) a solu...

59

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,...

60

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...

61

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...

62

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 ...

63

Applications of Monitored Natural Attenuation in the USA (Presentation)  

EPA Science Inventory

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

64

Applications of Monitored Natural Attenuation in the USA (Abstract)  

EPA Science Inventory

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

65

NATURAL GRADIENT EXPERIMENT ON SOLUTE TRANSPORT IN A SAND AQUIFER. 4. SORPTION OF ORGANIC SOLUTES AND ITS INFLUENCE ON MOBILITY  

EPA Science Inventory

Laboratory investigations were conducted to determine whether the observed field retardation of bromoform, carbon tetrachloride, tetrachloroethylene, 1,2-dichlorobenzene, and hexachloroethane at the Borden field site could be explained by the linear, reversible, equilibrium sorpt...

66

Transport in Porous Media 37: 327346, 1999. c 1999 Kluwer Academic Publishers. Printed in the Netherlands.  

E-print Network

reactive species. In recent years, increased interest in the fate and transport of reactive contam- inants. For example, chlorinated solvent contam- inants such as PCE (tetrachloroethylene) and TCE (trichloroethylene

Clement, Prabhakar

67

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

EPA Science Inventory

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

68

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...

69

BIOTRANSFORMATION OF TRICHLOROETHYLENE IN SOIL  

EPA Science Inventory

The organic contaminants that are most commonly detected in groundwater are low-molecular-weight, chlorinated aliphatic hydrocarbons such as trichloroethylene (TCE), tetrachloroethylene (PCE), 1,1,1-trichloroethane, carbon tetrachloride, and chloroform. The authors exposed unsatu...

70

The evolution of chlorine gas during degassing operations of aluminum using hexachloroethane tablets in relation to melt temperature and degasser depth  

E-print Network

. Tetrachloroethylene (C Cl ) has produced 7 signs of liver injury when inhaled by cats. It has a 30 TLV of 100 ppm. Below this concentration, serious effects are unlikely to occur. Carbon tetrachloride and carbon are formed from further decomposition.... Tetrachloroethylene (C Cl ) has produced 7 signs of liver injury when inhaled by cats. It has a 30 TLV of 100 ppm. Below this concentration, serious effects are unlikely to occur. Carbon tetrachloride and carbon are formed from further decomposition...

Kotrla, Claren James

2012-06-07

71

Environmental effects and fate of decontamination agent C-8 in soil  

SciTech Connect

Agent C-8 is a new Army decontamination agent designed to deactivate and remove chemical and biological warfare agents from vehicles and equipment. Its active ingredients are tetrachloroethylene (designated as a priority pollutant by the US Environmental Protection Agency) and calcium hypochlorite (a source of free chlorine). This laboratory study focused on the environmental fate of C-8 constituents in the soil ecosystem; the soil transport characteristics of, and potential for groundwater contamination by, tetrachloroethylene; and the effects of C-8 constituents on soil microorganisms. Four scenarios were developed to simulate most actual C-8 spills in the field. Soil columns in glass cylinders simulated the upper portion of a typical soil profile. Effluents and soils from each column were analyzed by gas chromatography to determine tetrachloroethylene concentrations. An identical set of soil samples was screened for effects on various groups of soil microorganisms. When tetrachloroethylene in C-8 enters the soil, it appears to be sorbed in certain profile regions and its movement is retarded with respect to that of water. This bound tetrachloroethylene appears to leach out of the soil profile over a long time, moving down toward groundwater at concentrations that are low (approx. = 10 ppM) compared with those originally applied to or retained in the soil. Effects on soil biota depend on physiological differences among species. Soil fungi appear to be affected most adversely, while some bacterial groups are unaffected by exposure to C-8 and others are enhanced. 13 refs., 17 figs., 5 tabs.

Zellmer, S.D.; Mego, W.A.; Hinchman, R.R.

1987-12-01

72

Some hepatotoxic actions of hexachloroethane and its metabolites in sheep  

PubMed Central

1. Pentachloroethane and tetrachloroethylene were major metabolites of hexachloroethane in sheep. 2. Concentrations of hexachloroethane, pentachloroethane and tetrachloroethylene were determined by gas-liquid chromatography in blood, bile, faeces, urine and tissues after oral administration of hexachloroethane emulsions to sheep. 3. Increased blood concentrations of sorbitol dehydrogenase, glutamate dehydrogenase, and ornithine carbamoyl transferase were found to follow oral administration of hexachloroethane or pentachloroethane. 4. The rate of bromsulphthalein transfer from liver cells to bile was found to decrease after oral administration of hexachloroethane. PMID:5809742

Fowler, J. S. L.

1969-01-01

73

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 ...

74

OXIDATION OF WATER SUPPLY REFRACTORY SPECIES BY OZONE WITH ULTRAVIOLET RADIATION  

EPA Science Inventory

The use of ozone with ultraviolet radiation was studied as an advanced treatment process for the removal of micropollutants and trihalomethane precursors from drinking water. The model compounds chloroform, bromo-dichloromethane, tetrachloroethylene and 2,2',4,4',6,6'-hexachlorob...

75

Association of biorefractories in drinking water and body burden in people  

Microsoft Academic Search

In New Orleans, Louisiana, where the Mississippi River serves as the water source, halogenated compounds like carbon tetrachloride, chloroform, and tetrachloroethylene were found to occur in both the finished water and blood of local residents. Of particular interest was the fact that blood from newborns was also found to contain several organics found in maternal blood that were also present

John L. Laseter; Betty J. Dowty

1977-01-01

76

pH control with silicates minerals for in situ bioremediation of chlorinated solventsfor in situ bioremediation of chlorinated solvents  

E-print Network

pH control with silicates minerals for in situ bioremediation of chlorinated solventsfor in situ bioremediation of chlorinated solvents Elsa Lacroix(1,2), Alessandro Brovelli(2), D.A. Barry(2), Christof (tetrachloroethylene), TCE 21 In situ bioremediation of chlorinated solvents is an acid-generating process. Acidic

77

Drinking water supply by reverse osmosis plants: three years of experience at El Prat de Llobregat Municipality  

Microsoft Academic Search

Deep coastal aquifer of Llobregat delta constitutes the main source of drinking water supply to El Prat de Llobregat municipality (64,000 inhabitants) near Barcelona (Spain). Since 70s this aquifer initiates a gradual salinization process by seawater intrusion, magnified by an exhaustive and not ordered water extraction. Also, aquifer pollution by volatile organic compounds (trichloroethylene and tetrachloroethylene) appeared in 90s. In

Joan Sanz; Aureliano García; Jordi Miró; Carlos Miguel

2012-01-01

78

Field evaluation of a simple microcosm simulating the behavior of volatile organic compounds in subsurface materials  

Microsoft Academic Search

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, and hexachloroethane in (1) the microcosm, (2) the microcosm constructed with autoclaved material, and (3) an experimental plume constructed in a joint field study conducted by

John T. Wilson; Garmon B. Smith; Jack W. Cochran; James F. Barker; Paul V. Roberts

1987-01-01

79

Influence of Water Content and Plants on the Dissipation of Chlorinated Volatile Organic Compounds in Soil  

Microsoft Academic Search

To devise effective procedures for the remediation of soil contaminated by VOCs, an improved understanding of their fate and transport mechanisms in soil is essential. To show the effect of plants on the dissipation of 1,1,1-trichloroethane (TCA), trichloroethylene (TCE) and tetrachloroethylene (PCE), two types of experiments, vial and column, were conducted. The results suggested that keeping the soil moisture content

Changhwan Cho; Kijune Sung; M. Yavuz Coapcioglu; Malcolm Drew

2005-01-01

80

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

EPA Science Inventory

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

81

Analytical Modeling of A By-product Transport in Chain Reactions  

Microsoft Academic Search

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

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

2003-01-01

82

Environmental effects and fate of decontamination agent C-8 in soil  

Microsoft Academic Search

Agent C-8 is a new Army decontamination agent designed to deactivate and remove chemical and biological warfare agents from vehicles and equipment. Its active ingredients are tetrachloroethylene (designated as a priority pollutant by the US Environmental Protection Agency) and calcium hypochlorite (a source of free chlorine). This laboratory study focused on the environmental fate of C-8 constituents in the soil

S. D. Zellmer; W. A. Mego; R. R. Hinchman

1987-01-01

83

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

Microsoft Academic Search

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

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

2003-01-01

84

Nonaqueous Phase Liquid Dissolution in Porous Media: Multi-Scale Effects of MultiComponent Dissolution Kinetics on Cleanup Time  

Microsoft Academic Search

Industrial organic solvents such as trichloroethylene (TCE) and tetrachloroethylene (PCE) constitute a principal class of groundwater contaminants. Cleanup of groundwater plume source areas associated with these compounds is problematic, in part, because the compounds often exist in the subsurface as dense nonaqueous phase liquids (DNAPLs). Ganglia (or 'blobs') of DNAPL serve as persistent sources of contaminants that are difficult to

W McNab; S Ezzedine; R Detwiler

2007-01-01

85

Effect of biosurfactants on the aqueous solubility of PCE and TCE  

Microsoft Academic Search

The effect of biosurfactants on the solubility of tetrachloroethylene (PCE) and trichloroethylene (TCE) was studied in batch experiments pertaining to their use for solubilization and mobilization of such contaminants in surfactant enhanced aquifer remediation. Biosurfactants, rhamnolipid and surfactin used in solubility studies were synthesized in our laboratory by Pseudomonas aeruginosa (MTCC 2297) and Bacillus subtilis (MTCC 2423), respectively. The efficiency

John D. Albino; Indumathi M. Nambi

2009-01-01

86

Reductive dechlorination of trichloroethylene in anoxic aquifer material from Picatinny Arsenal, New Jersey. Water Resources Investigation  

SciTech Connect

Ground water at Picatinny Arsenal, New Jersey, has been contaminated with chlorinated solvents released from the waste water-treatment system of a metal-plating shop and from overflow from a degreasing vat. Trichloroethylene is the major contaminant, but 1,1,1-trichloroethane and tetrachloroethylene are also present. Cis-1,2-dichloroethylene and vinyl chloride were not original contaminants, but their accumulation in the ground water indicates reductive dechlorination of the trichloroethylene and tetrachloroethylene released to the aquifer. Laboratory microcosms were used to estimate the kinetics of reductive dechlorination at field scale. The microcosms were constructed with aquifer material collected from locations along the longitudinal extent of the plume and from outside the area of contamination. To determine whether supplementary electron donors would enhance reductive dechlorination, three suites of electron donors were added to aquifer material: (1) butyrate, propionate, toluene, and p-cresol; (2) butyrate, propionate, formate, methanol, toluene, and p-cresol; or (3) formate and methanol.

Wilson, B.H.; Ehlke, T.A.; Imbrigiotta, T.E.; Wilson, J.T.

1991-01-01

87

Health assessment for Keystone Sanitation Landfill, Union Township, Adams County, Pennsylvania, Region 3. CERCLIS No. PAD054142781. Preliminary report  

SciTech Connect

The Keystone Sanitation Landfill site is a former farm which began receiving municipal waste and industrial construction debris in September 1966. The still active site is situated on a ridge, and runoff leaves the site from all directions. The environmental contamination on-site consists of 1,1,1-trichloroethane, trichloroethylene, vinyl chloride, benzene, 1,1-dichloroethane, 1,1-dichloroethylene, tetrachloroethylene, trans-1,2-dichloroethylene, chromium, lead, and N-nitrosodiphenylamine in groundwater. The environmental contamination off-site consists of tetrachloroethylene, 1,1,1-trichloroethane, 1,1-dichloroethylene, 1,1-dichloroethane, trichloroethylene in surface water; and lead, vinyl chloride, and 1,2-dichloroethylene in private wells. 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 groundwater, soil, and surface water.

Not Available

1988-10-11

88

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

89

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

90

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

91

Gas phase photocatalytic degradation on TiOâ pellets of volatile chlorinated organic compounds from a soil vapor extraction well  

Microsoft Academic Search

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 TiOâ pellets in field trials at the Savannah River Site in Aiken, SC. The TiOâ pellets were prepared using a sol-gel method. The experiments were performed at 55 to 60°C using space

S. Yamazaki-Nishida; H. W. Read; J. K. Nagano; M. A. Anderson; S. Cervera-March; T. R. Jarosch; C. A. Eddy-Dilek

1993-01-01

92

Gas phase photocatalytic degradation on TIO2 pellets of volatile chlorinated organic compounds from a soil vapor extraction well  

Microsoft Academic Search

The degradation of trichloroethylene (TCE, Cl2C=CHCl) and tetrachloroethylene (PCE, Cl2C=CCI2) in a gas stream from a soil vapor extraction (SVE) well was demonstrated with an annular photocatalytic reactor packed with porous TiO2 pellets in a field trial at the Savannah River Site in Aiken, SC. The TiO2 pellets were prepared using a sol?gel method. The experiments were performed at 55

Harry W. Read; Joyce K. Nagano; Tim Jarosch; Carol Eddy; Marc A. Anderson

1994-01-01

93

Biodegradation of chlorinated aliphatic hydrocarbon mixtures in a single-pass packed-bed reactor  

Microsoft Academic Search

Aliphatic chlorinated compounds, such as trichloroethylene (TCE) and tetrachloroethylene (PCE), are major contaminants of\\u000a ground water. A single-pass packed-bed bioreactor was utilized to study the biodegradation of organic waste mixtures consisting\\u000a of PCE, TCE, and other short-chain chlorinated organics. The bioreactor consisted of two 1960-mL glass columns joined in a\\u000a series. One column was packed with sand containing a microbial

L. W. Lackey; T. J. Phelps; P. R. Bienkowski; D. C. White

1993-01-01

94

H-Area Seepage Basins groundwater monitoring report  

SciTech Connect

During first quarter 1992, tritium, nitrate, nonvolatile beta, total alpha-emitting radium (radium-224 and radium-226), gross alpha, antimony, 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 Site. This report presents and discusses the groundwater monitoring results in the H-Area for first quarter 1992.

Thompson, C.Y.

1992-06-01

95

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

SciTech Connect

During first quarter 1992, tritium, nitrate, nonvolatile beta, total alpha-emitting radium (radium-224 and radium-226), gross alpha, antimony, 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 Site. This report presents and discusses the groundwater monitoring results in the H-Area for first quarter 1992.

Thompson, C.Y.

1992-06-01

96

Surface changes in well-casing pipe exposed to high concentrations of organics in aqueous solution. Special report  

Microsoft Academic Search

This preliminary study was undertaken to assess how the surface structural characteristics of four common well casing materials-polyvinyl chloride (PVC), Teflon (polytetrafluoroethylene, PTFE), stainless steel 304 (SS304) and stainless steel 316 (SS316)-are affected by exposure to an aqueous solution containing tetrachloroethylene, toluene, p-dichlorobenzene and 0-dichlorobenzene in concentrations near their solubility. Casing samples that had been exposed to a test solution

S. Taylor; L. Parker

1990-01-01

97

Reductive dechlorination catalyzed by bacterial transition-metal coenzymes  

Microsoft Academic Search

The bacterial transition-metal coenzymes vitamin Bââ (Co), coenzyme Fâââ (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 Bââ and coenzyme Fâââ, 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

98

Ligandless-ultrasound-assisted emulsification microextraction followed by inductively coupled plasma-optical emission spectrometry for simultaneous determination of heavy metals in water samples  

Microsoft Academic Search

In this study, a simple and efficient method of ligandless-ultrasound-assisted emulsification microextraction (LL-USAEME) followed by inductively coupled plasma-optical emission spectrometry (ICP-OES) has been developed for simultaneous extraction, preconcentration and determination of manganese, cadmium, cobalt and nickel in water samples. In the proposed approach, tetrachloroethylene was selected as extraction solvent. The effect of important experimental factors such as volume of extraction

Maryam Karimi; Hassan Sereshti; Vahid Khojeh; Soheila Samadi

2012-01-01

99

Evaluacion experimental del factor de estabilidad en nanoemulsiones dodecano/agua  

E-print Network

The turbidity of four different oil/water (o/w) ionic nanoemulsions is studied as a function of time. The emulsions are stabilized with sodium dodecyl sulphate, and are composed of pure dodecane, and mixtures of dodecane, squalene and tetrachloroethylene. For each system plots of the stability factor as a function of the ionic strength of the solution are reported. The results allow establishing the relative importance of buoyancy and Ostwald ripening on the aggregation rates.

Yorlis Mendoza; Kareem Rahn-Chique; German Urbina-Villalba

2013-03-08

100

Distribution of selected volatile organic compounds determined with water-to-vapor diffusion samplers at the interface between ground water and surface water, Centredale Manor site, North Providence, Rhode Island, September 1999  

USGS Publications Warehouse

Volatile organic compounds are present in soils and ground water at the Centredale Manor Superfund Site in North Providence, Rhode Island. In September 1999, water-to-vapor diffusion samplers were placed in the bottom sediments of waterways adjacent to the site to identify possible contaminated ground-water discharge areas. The approximate12-acre site is a narrow stretch of land between the eastern bank of the Woonasquatucket River, downstream from the U.S. Route 44 bridge and a former mill raceway. The samplers were placed along a 2,250-foot reach of the Woonasquatucket River, in the former mill raceway several hundred feet to the east and parallel to the river, and in a cross channel between the river and former mill raceway. Volatile organic compounds were detected in 84 of the 104 water-to-vapor diffusion samplers retrieved. Trichloroethylene and tetrachloro-ethylene were the principal volatile organic compounds detected. The highest vapor concentrations measured for these two chemicals were from diffusion samplers located along an approximate 100-foot reach of the Woonasquatucket River about 500 feet downstream of the bridge; here trichloroethylene and tetrachloroethylene vapor concentrations ranged from about 2,000 to 180,000 and 1,600 to 1,400,000 parts per billion by volume, respectively. Upstream and downstream from this reach and along the former mill raceway, trichloroethylene and tetrachloroethylene vapor concentrations from the diffusion samples were generally less than 100 parts per billion by volume. Along the lower reaches of the river and mill raceway, however, and in the cross channel, vapor concentrations of trichloroethylene exceeded 100 parts per billion by volume and tetrachloroethylene exceeded 1,000 parts per billion by volume in several diffusion samples. Although diffusion sample vapor concentrations are higher than water concentrations in surface waters and in ground water, and they should only be interpreted qualitatively as relative values, these values provide important information as to potential discharge areas of contaminants.

Church, Peter E.; Lyford, Forest P.; Clifford, Scott

2000-01-01

101

Contamination of shallow ground water in the area of building 95, Picatinny Arsenal, New Jersey, 1985-90  

USGS Publications Warehouse

A zone of contaminated ground water at Picatinny Arsenal has resulted from the operation of a metal- plating facility in building 95 during 1960-81, and the wastewater-treatment system that is in and adjacent to the building. Thirty-two monitoring wells were installed in 1989 to supplement 12 previously installed wells. All wells were sampled in 1989 and 1990 for analysis of ground water for inorganic constituents, trace elements, volatile organic compounds, and nutrients. Four wells also were sampled for analysis for base/neutral- and acid-extractable compounds and pesticides, and soil gas from the unsaturated zone at eight sites was analyzed for volatile organic compounds. Concentrations of dissolved solids and sulfate in the study area were consistently above the U.S. Environmental Protection Agency's secondary drinking-water regulations. The areal distribution of sulfate differed from that of the volatile organic compounds. Concentrations of trace elements were not elevated downgradient from the source. The estimated average velocity of contaminant movement is 0.1 to 1.1 feet per day. The major organic contaminants identified in the study area are trichloroethylene, tetrachloroethylene, and 1,1,1-trichloroethane. Trichloroethylene was detected in wells upgradient from the wastewater- treatment site. Tetrachloroethylene and 1,1,1-trichloroethane might originate at tanks in the basement of building 95 rather than at the adjacent wastewater-treatment system. The pre- dominant gas-phase contaminant, 1,1,1- trichloroethane, was detected at a maximum con- centration of 15.7 micrograms per liter. Both trichoroethylene and tetrachloroethylene were detected in concentrations greater than 0.10 micrograms per liter in five of the eight soil- gas samples, indicating that volatilization and diffusion through the unsaturated zone could be a significant mechanism of contaminant loss from the aquifer.

Sargent, B. P.; Storck, D. A.

1994-01-01

102

Children's Exposure to Volatile Organic Compounds as Determined by Longitudinal Measurements in Blood  

PubMed Central

Blood concentrations of 11 volatile organic compounds (VOCs) were measured up to four times over 2 years in a probability sample of more than 150 children from two poor, minority neighborhoods in Minneapolis, Minnesota. Blood levels of benzene, carbon tetrachloride, trichloroethene, and m-/p-xylene were comparable with those measured in selected adults from the Third National Health and Nutrition Examination Survey (NHANES III), whereas concentrations of ethylbenzene, tetrachloroethylene, toluene, 1,1,1-trichloroethane, and o-xylene were two or more times lower in the children. Blood levels of styrene were more than twice as high, and for about 10% of the children 1,4-dichlorobenzene levels were ?10 times higher compared with NHANES III subjects. We observed strong statistical associations between numerous pairwise combinations of individual VOCs in blood (e.g., benzene and m-/p-xylene, m-/p-xylene and o-xylene, 1,1,1-trichloroethane and m-/p-xylene, and 1,1,1-trichloroethane and trichloroethene). Between-child variability was higher than within-child variability for 1,4-dichlorobenzene and tetrachloroethylene. Between- and within-child variability were approximately the same for ethylbenzene and 1,1,1-trichloroethane, and between-child was lower than within-child variability for the other seven compounds. Two-day, integrated personal air measurements explained almost 79% of the variance in blood levels for 1,4-dichlorobenzene and approximately 20% for tetrachloroethylene, toluene, m-/p-xylene, and o-xylene. Personal air measurements explained much less of the variance (between 0.5 and 8%) for trichloroethene, styrene, benzene, and ethylbenzene. We observed no significant statistical associations between total urinary cotinine (a biomarker for exposure to environmental tobacco smoke) and blood VOC concentrations. For siblings living in the same household, we found strong statistical associations between measured blood VOC concentrations. PMID:15743726

Sexton, Ken; Adgate, John L.; Church, Timothy R.; Ashley, David L.; Needham, Larry L.; Ramachandran, Gurumurthy; Fredrickson, Ann L.; Ryan, Andrew D.

2005-01-01

103

Intermedia transfer factors for fifteen toxic pollutants released to air basins in California  

SciTech Connect

This report provides a summary definition of the intermedia-transfer factors (ITFs). Methods are discussed for estimating these parameters in the absence of measured values, and the estimation errors inherent in these estimation methods are considered. A detailed summary is provided of measured and estimated ITF values for fifteen air contaminants. They include: 1,3 butadiene; cadmium; cellosolve; cellosolve acetate; chloroform; di-2-ethylhexylphthalate; 1,4-dioxame; hexachlorobenzene; inorganic arsenic; inorganic lead; nickel; tetrachloroethylene; toluene; toluene-2,4-diisocyanate; and 1,3-xylene. Recommendations are made regarding the expected value and variance in these values for use in exposure models.

McKone, T.E.; Daniels, J.I. [Lawrence Livermore National Lab., CA (United States); Chiao, F.F.; Hsieh, D.P.H. [Univ. of California, Davis, CA (United States)

1993-10-01

104

H-Area Seepage Basins. Third quarter 1990 groundwater quality assessment report  

SciTech Connect

During the third quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium.

Stejskal, G.

1990-12-01

105

H-Area Seepage Basins  

SciTech Connect

During the third quarter of 1990 the wells which make up the H-Area Seepage Basins (H-HWMF) monitoring network were sampled. Laboratory analyses were performed to measure levels of hazardous constituents, indicator parameters, tritium, nonvolatile beta, and gross alpha. A Gas Chromatograph Mass Spectrometer (GCMS) scan was performed on all wells sampled to determine any hazardous organic constituents present in the groundwater. The primary contaminants observed at wells monitoring the H-Area Seepage Basins are tritium, nitrate, mercury, gross alpha, nonvolatile beta, trichloroethylene (TCE), tetrachloroethylene, lead, cadmium, arsenic, and total radium.

Stejskal, G.

1990-12-01

106

Intelligent Unmanned Monitoring of Remediated Sites  

SciTech Connect

During this Phase I project, IOS demonstrated the feasibility of combining digital signal processing and neural network analysis to analyze spectral signals from pure samples of several typical contaminants. We fabricated and tested a prototype system by automatically analyzing Raman spectral data taken in the Vadose zone at the 321 M site in the M area of DOE's Savannah River Site in South Carolina. This test demonstration proved the ability of IOS's technology to detect the target contaminants, tetrachloroethylene (PCE) and trichloroethylene (TCE), in isolation, and to detect the spectra of these contaminants in real-world noisy samples taken from a mixture of materials obtained from this typical remediation target site.

Emile Fiesler, Ph.D.

2001-06-01

107

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

108

Metallurgical Laboratory Hazardous Waste Management Facility groundwater monitoring report: Third quarter 1993  

SciTech Connect

During third quarter 1993, samples from AMB groundwater monitoring wells at the Metallurgical Laboratory Hazardous Waste Management Facility were analyzed for certain heavy metals, indicator parameters, radionuclides, volatile organic compounds, and other constituents. Eight parameters exceeded standards during the quarter. As in previous quarters, tetrachloroethylene and trichloroethylene exceeded final Primary Drinking Water Standards; and aluminum, iron, lead, manganese, pH, and total organic halogens exceeded the Savannah River Site Flag 2 criteria in one or more of the wells. Groundwater flow direction and rate in the water-table unit were similar to previous quarters.

Not Available

1993-12-01

109

High charged red pigment nanoparticles for electrophoretic displays  

NASA Astrophysics Data System (ADS)

Organic pigment permanent red F2R nanoparticles were prepared via surface modification to improve the surface charge and dispersion ability in organic medium. Their large surface chargeability is confirmed by ?-potential value of -49.8 mV. The prepared particles exhibited average size of 105 nm and showed very narrow distribution with polydispersity index of 0.068. The sedimentation ratio of the prepared particles in tetrachloroethylene was less than 5% within 12 days. The electrophoretic inks consisting of the prepared red particles with white particles as contrast showed good electrophoretic display, its refresh time was 200 ms.

Hou, Xin-Yan; Bian, Shu-Guang; Chen, Jian-Feng; Le, Yuan

2012-12-01

110

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

111

Evaluation of internal standards for the analysis of ignitable liquids in fire debris.  

PubMed

An evaluation of eight compounds for use as an internal standard in fire debris analysis was conducted. Tests were conducted on tetrachloroethylene, chlorobenzene, n-octylbenzene, 3-phenyltolune, and deuterated compounds toluene-d8, styrene-d8, naphthalene-d8, and diphenyl-d10 to measure the extraction efficiency of each compound in the presence of an interfering volatile compound (carbon disulfide). Other tests were conducted to evaluate whether or not the presence of an ignitable liquid or pyrolysis/combustion products from fire debris would interfere with the identification of these compounds when used as an internal standard. The results showed that while any of the eight compounds could be used as an internal standard in fire debris analysis, the more volatile compounds (toluene-d8, tetrachloroethylene, chlorobenzene, and styrene-d8) showed better extraction efficiencies at room temperature than when heated to 60 degrees C. Each of the less volatile compounds (naphthalene-d8, diphenyl-d10, n-octylbenzene, and 3-phenyltolune) performed well during extraction at 60 degrees C, while naphthalene-d8 showed better extraction efficiency in the presence of competing volatiles when extracted at room temperature. PMID:19175707

Locke, Amanda K; Basara, Gene J; Sandercock, P Mark L

2009-03-01

112

Solvent Vapour Detection with Cholesteric Liquid Crystals--Optical and Mass-Sensitive Evaluation of the Sensor Mechanism†  

PubMed Central

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.

2010-01-01

113

A comparative study of the excretion of Fujiwara reaction-positive substances in urine of humans and rodents given trichloro- or tetrachloro-derivatives of ethane and ethylene  

PubMed Central

Ikeda, M., and Ohtsuji, H. (1972).Brit. J. industr. Med.,29, 99-104. A comparative study or the excretion of Fujiwara reaction-positive substances in urine of humans and rodents given trichloro- or tetrachloro-derivatives of ethane and ethylene. 1,1,1-Trichloroethane, 1,1,2- trichloroethane, 1,1,1,2-tetrachloroethane, 1,1,2,2-tetrachloroethane, trichloroethylene, and tetrachloroethylene were administered to rats and mice as vapours at 200 p.p.m. for 8 hours and urine was collected for 48 hours. The urine was analysed by the Fujiwara reaction for total trichlorocompounds (TTC), trichloroacetic acid (TCA), and trichloroethanol (TCE). All compounds except 1,1,2-trichloroethane yielded substantial TCA and TCE but 1,1,1,2-tetrachloroethane and trichloroethylene much more than the rest. The results obtained during two periods of 48 hours after intraperitoneal injection were similar. The variations in the amounts of metabolites are shown to be consistent with the vapour pressures of the solvents (compounds with high vapour pressures are lost from the lungs before being metabolized) and with their known chemical properties, according to which 1,1,1-trichlorocompounds should yield TCE and TCA readily, whereas 1,1,2-chlorocompounds should not. Excretion of metabolites from men exposed intermittently to vapours of tetrachloroethylene and trichloroethylene were also studied. Both gave enough TCE and TCA, but trichloroethylene gave considerably more, in accordance with its relative instability to oxidation. PMID:5060252

Ikeda, Masayuki; Ohtsuji, Hatsue

1972-01-01

114

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

115

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

116

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

SciTech Connect

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 it a potential target for detection by ground-penetrating radar (GPR). GPR data were acquired using 200 MHz antennas. Radar sections collected at different times over the same spatial location clearly show the changes induced by the movement of DNAPL in the subsurface. Temporal changes can be examined through the evolution of a radar data trace collected at a single spatial location. Normal moveout analysis of common-midpoint (CMP) data demonstrates induced changes in electromagnetic (EM) wave velocities of up to 30% caused by the presence of DNAPL. The distribution of DNAPL can be mapped in three dimensions at different times using a network of 16 radar lines. The 200 MHz GPR proved to be an effective technique for monitoring the movement of DNAPL in the subsurface. Direct detection of DNAPLs by radar is also feasible in this simple environment.

Brewster, M.L. (Komex International Ltd., Calgary, Alberta (Canada) Univ. of Waterloo, Ontario (Canada). Waterloo Centre for Groundwater Research); Annan, A.P. (Sensors and Software, Inc., Mississauga, Ontario (Canada) Univ. of Waterloo, Ontario (Canada). Waterloo Centre for Groundwater Research)

1994-08-01

117

Health assessment for PSC Resources, Inc. , Palmer, Massachusetts, Region 1. CERCLIS No. MAD980731483. Final report  

SciTech Connect

The PSC Resources, Inc. site is listed by the U.S. Environmental Protection Agency (EPA) on the National Priorities List (NPL). The 3.6-acre PSC Resources, Inc. site is located at 10 Water Street, Palmer, Massachusetts. A waste oil refinery and solvent recovery plant operated on-site until the facility was abandoned by the owner in 1978. Millions of gallons of waste were left behind in tanks and lagoons. Contamination of soil, surface water and ground water occurs on-site. Soil contamination includes polychlorinated biphenyls at concentrations up to 30 ppm and lead. Surface water present in dikes contained lead and benzene. Oil sampled in the dikes contained cadmium, lead, benzene and PCBs. Oil found in a rainwater catchbasin contained Aroclor-1242 and tetrachloroethylene. Shallow ground water contamination consisted mostly of volatile organic compounds including 1,1,1-trichloroethane (40 ppm), trichloroethylene, benzene, methylene chloride, trans-1,2-dichloroethylene and tetrachloroethylene. Off-site contamination data is scant, as the Remedial Investigation has not been completed. 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 significant levels of hazardous substances via the interception of contaminated ground water by private residential wells, the possible transport of contaminants off-site during flood events, and the recreational use of the nearby wetland and Quaboag River.

Not Available

1989-04-18

118

Adsorption of low molecular weight halocarbons by montmorillonite  

SciTech Connect

Montmorillonite clay from Clay Spur, WY, was found to adsorb several low molecular weight, hydrophobic halocarbons from aqueous solution at sub-parts-per-million levels. The halocarbons studied were trichloroethylene, tetrachloroethylene, hexachloroethane, and dibromochloropropane. When the montmorillonite was treated with sodium citrate-bicarbonate-dithionite (CBD), it adsorbed higher levels of halocarbons than the untreated clay. In addition, the CBD-treated clay exhibited a maximum in halocarbon adsorption around pH 4, while untreated clay showed little variation in adsorption over the pH range 2-10. Adsorption of trichloroethylene was inhibited by low concentrations of sodium chloride (0.01 M or greater) in solution. Aging the CBD-treated clay in water decreased its capacity to adsorb trichloroethylene. Desorption studies showed that the sorption of tetrachloroethylene to CBD-treated clay is an irreversible process when compared to sorption by fumed silica. The ability of montmorillonite to adsorb halocarbons and the instability of the clay in water are postulated to involve changes in the oxide surface coating on the clay.

Estes, T.J.; Shah, R.V.; Vilker, V.L. (Univ. of California, Los Angeles (USA))

1988-04-01

119

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. PMID:22557812

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

2012-01-01

120

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

121

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

122

Vapor vacuum extraction treatability study at the Idaho National Engineering Laboratory  

SciTech Connect

During the 1960s and early 1970s, barreled mixed waste containing volatile organic compounds (VOCS) and radioactive waste was buried at the Subsurface Disposal Area (SDA) at the Idaho National Engineering Laboratory (INEL) Radioactive Waste Management Complex (RWMC). Over time, some of the barrels have deteriorated allowing, VOC vapors to be released into the vadose zone. The primary VOC contaminates of concern are CCl{sub 4} and trichloroethylene; however, chloroform, tetrachloroethylene, and 1,1,1-trichloroethane have also been detected. Vapor Vacuum Extraction (VVE) is one alternative being considered for remediation of the RWMC SDA vadose zone. A proposed pilot-scale treatability study (TS) will provide operation and maintenance costs for the design of the potential scale-up of the system.

Herd, M.D.; Matthern, G.; Michael, D.L.; Spang, N.; Downs, W.; Weidner, J. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Cleary, P. [USDOE Idaho Field Office, Idaho Falls, ID (United States)

1993-05-01

123

Analysis and evaluation of VOC removal technologies demonstrated at Savannah River  

SciTech Connect

Volatile Organic Compounds, or VOCs, are ubiquitous subsurface contaminants at industrial as well as DOE sites. At the Savannah River Plant, the principles VOCs contaminating the subsurface below A-Area and M-Area are Trichloroethylene (C{sub 2}HCl{sub 3}, or TCE) and Tetrachloroethylene (C{sub 2}Cl{sub 4}, or PCE). These compounds were used extensively as degreasing solvents from 1952 until 1979, and the waste solvent which did not evaporate (on the order of 2{times}10{sup 6} pounds) was discharged to a process sewer line leading to the M-Area Seepage Basin (Figure I.2). These compounds infiltrated into the soil and underlying sediments from leaks in the sewer line and elsewhere thereby contaminating the vadose zone between the surface and the water table as well as the aquifer.

Chesnut, D.A.; Wagoner, J.; Nitao, J.J.; Boyd, S.; Shaffer, R.J.; Kansa, E.J.; Buscheck, T.A. [Lawrence Livermore National Lab., CA (United States); Pruess, K. [Lawrence Berkeley Lab., CA (United States); Falta, R.W. [Clemson Univ., SC (United States)

1993-09-01

124

FTIR investigation of adsorption and chemical decomposition of CCl4 by high surface-area aluminum oxide.  

PubMed

Chlorinated hydrocarbons are among the most recalcitrant pollutants for control by sorption or catalytic destruction. High surface-area alumina holds promise as a catalytic media as well as a component of other binary catalyst systems. We have prepared an alumina catalyst using the aerogel technique that has a very high surface area of 550 m2/g. This catalyst destroys carbon tetrachloride with an efficiency >99% at 400 degrees C. Its reactivity toward carbon tetrachloride is remarkably higher than that of commercial alumina, which has a surface area of 155 m2/g. Carbon dioxide is the major product. Minor products include hydrogen chloride and tetrachloroethylene along with traces of phosgene. Some of the carbon tetrachloride reacts with the alumina to form aluminum chloride, which vaporizes to reveal a fresh catalytic surface. A mechanism for adsorption and destruction has been developed that involves chemisorption followed by surface to adsorbate oxygen transfer and adsorbate to surface chlorine transfer. PMID:11999074

Khaleel, Abbas; Dellinger, Barry

2002-04-01

125

Risk assessment of seeps from the 317 Area of Argonne National Laboratory  

SciTech Connect

Chlorinated hydrocarbon contaminants have recently been detected in groundwater seeps on forest preserve property south of the 317 Area at ANL. The 317 Area is near ANL`s southern boundary and is considered the source of the contamination. Five seeps are about 200 m south of the ANL property line and about same distance from the nearest developed trails in the forest preserve. Conservative assumptions were used to assess the possibility of adverse health effects associated with forest preserve seeps impacted by the 317 Area. Results indicate that neither cancer risks nor noncarcinogenic effects associated with exposures to seep contaminants are a concern; thus, the area is safe for all visitors. The ecological impact study found that the presence of the three contaminants (CCl{sub 4}, CHCl{sub 3}, tetrachloroethylene) in the seep water does not pose a risk to biota in the area.

NONE

1996-09-17

126

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

127

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

128

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

129

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

130

Different behavioral effect dose-response profiles in mice exposed to two-carbon chlorinated hydrocarbons: influence of structural and physical properties.  

PubMed

The present study aimed to clarify whether dose-response profiles of acute behavioral effects of 1,2-dichloroethane (DCE), 1,1,1-trichloroethane (TCE), trichloroethylene (TRIC), and tetrachloroethylene (PERC) differ. A test battery involving 6 behavioral endpoints was applied to evaluate the effects of DCE, TCE, TRIC, and PERC in male ICR strain mice under the same experimental conditions. The behavioral effect dose-response profiles of these compounds differed. Regression analysis was used to evaluate the relationship between the dose-response profiles and structural and physical properties of the compounds. Dose-response profile differences correlated significantly with differences in specific structural and physical properties. These results suggest that differences in specific structural and physical properties of DCE, TCE, TRIC, and PERC are responsible for differences in behavioral effects that lead to a variety of dose-response profiles. PMID:24910396

Umezu, Toyoshi; Shibata, Yasuyuki

2014-09-01

131

Metallurgical Laboratory Hazardous Waste Management Facility groundwater monitoring report. Second quarter 1994  

SciTech Connect

During second quarter 1994, samples from AMB groundwater monitoring wells at the Metallurgical Laboratory Hazardous Waste Management Facility were analyzed for selected heavy metals, indicator parameters, radionuclides, volatile organic compounds, and other constituents. Three parameters exceeded standards during the quarter. As in previous quarters, tetrachloroethylene and trichloroethylene exceeded final Primary Drinking Water Standards. Total organic halogens exceeded the Savannah River Site (SRS) Flag 2 criteria in two of the wells. Groundwater flow direction and rate in the M-Area Aquifer Zone were similar to previous quarters. Conditions affecting 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. During second quarter 1994, SRS received SCDHEC approval for five point-of-compliance wells and two plume definition wells near the Met Lab HWMF. Field work has begun on this project.

Not Available

1994-09-01

132

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

133

Superfund Record of Decision (EPA Region 2): Katonah Municipal Well, Bedford, New York (first remedial action), September 1987. Final report  

SciTech Connect

The Katonah Municipal Well site is located in the Village of Katonah in the Town of Bedford, Westchester County, New York. The well is situated on a peninsula owned by the City of New York that extends into the Muscoot Reservoir. In 1978 the Westchester County Department of Health (WCDH), acting on Putnam County Health Department findings, sampled the Katonah well and other local wells for contamination. These samples revealed the presence of tetrachloroethylene (PCE) and other VOCs in the well water. These contaminants were traced to a local septic waste collector who was disposing of wastes taken from several Katonah dry-cleaning establishments. In 1978 the Katonah well was closed and source-control measures were initiated requiring dry cleaning establishments to pump out their septic systems and modify solvent-disposal techniques. Initial attempts by WCDH and the Town of Bedford to remove contamination from the affected aquifer failed. The primary contaminant of concern affecting the ground water is PCE.

Not Available

1987-09-25

134

Solubility of liquid organics of environmental interest in subcritical (hot/liquid) water from 298 K to 473 K  

SciTech Connect

The solubilities of benzene, toluene, m-xylene, p-cymene, octane, 2,2,4-trimethylpentane (isooctane), tetrachloroethylene, 1,2-dichlorobenzene, and tetraethyltin were determined at temperatures ranging from 298 K to 473 K. Increasing the temperature up to 473 K increased the solubilities by a factor of {approximately}10--250. For example, increasing the temperature from 298 K to 473 K increased the mole fraction solubility of tetraethyltin from (0.03 {+-} 0.002) x 10{sup {minus}7} to (8.8 {+-} 0.6) x 10{sup {minus}7} but only increased the solubility of benzene from (4.0 {+-} 0.1) x 10{sup {minus}4} to (41 {+-} 3) x 10{sup {minus}4}. Pressure had a minimal effect; for example, increasing the pressure from 65 to 400 bar at either 298 K or 473 K reduced the solubility of benzene by only {approximately}20%.

Miller, D.J.; Hawthorne, S.B.

2000-02-01

135

In situ bioremediation using the UVB{trademark} technology: Description and case study  

SciTech Connect

Under a Multi-Vendor Biotreatability Demonstration Program, SBP Technologies, Inc. (SBP) conducted a field demonstration of a microbiologically enhanced in situ groundwater and soil treatment technology at the Sweden-3 Chapman Superfund Site, Brockport, New York. The Sweden-3 Chapman site is an inactive landfill used to dispose of construction/demolition debris and hazardous wastes between the years of 1970 and 1978. Site investigations conducted in 1985 by NYSDEC indicated that drums were buried throughout the landfill. These drums and on-site soils were sampled in 1987, indicating elevated levels of trichloroethylene (TCE), methylene chloride, tetrachloroethylene (PCE), and acetone among other volatile organics (VOCs) and semi-volatile organics (SVOCs). In 1992, a remedial investigation identifies source areas and determined the extent of vertical and horizontal migration of contaminants at the site. Information and data generated during these investigations set the foundation for conducting the multi-vendor biotreatability demonstration.

Mueller, J.G.; Desrosiers, R.J.; Lakhwala, F.S.; Borchert, S. [SBP Technologies, Inc., Gulf Breeze, FL (United States)

1996-12-31

136

Analysis of organic compounds (VOC) in the forest air of the Southern Black Forest  

SciTech Connect

The volatile organic compounds of forest air (Kaelbelescheuer, Southern Black Forest) and, for comparison, suburban air (Tuebingen) were qualitatively analyzed by gas chromatographic and mass spectrometric methods. 94 Individual compounds were identified, 6 of them belonged to biogenic monoterpenes (..cap alpha..-pinene, ..delta..3-carene, myrcene, limonene, eucalyptol, camphene). While the monoterpenes were enriched in forest air, a similar collection of the pollution products was observed in both locations. Predominant substances were aromatic compounds (toluene, ethylbenzene, benzene, xylenes, ethyltoluenes, pseudocumene and naphthalene) which can be regarded as constituents of vehicle exhaust fumes and incineration processes. Other important substances in forest air were various solvents, of which butyl acetate, isobutyl acetate, tetrachloroethylene and trichloroethylene, butanol-1, and several ketones were prominent species.

Juettner, F.

1986-01-01

137

Public health assessment for petitioned public health assessment, Falls Township groundwater contamination (a/k/a Corco Chemical, Parascientific, Meenan Oil), Falls Township, Bucks County, Pennsylvania, Region 3. Final report  

SciTech Connect

The Falls Township Groundwater Contamination site, Bucks County, Pennsylvania, has been evaluated for public health issues at the request of citizens in the community. Portions of the groundwater in an area of the township have been sampled and found to be adversely affected by releases of chemicals; potential sources of contaminants may include both industrial and non-industrial activities. The principal compounds are trichloroethylene, tetrachloroethylene, and chloroform. ATSDR's review of human activities and the limited sampling information also suggests that some persons in the study area potentially may be exposed to hazardous substances by inhaling affected ambient air, or by intermittent soil ingestion, or possibly, through intermittent recreational activities at local surface water bodies or intermittent consumption of fish from surface waters.

Not Available

1994-01-10

138

Brine shrimp (Artemia salina) nauplii as a teratogen test system.  

PubMed

Brine shrimp increase in length rapidly after hatching. A teratogen test system is based on disruption of elongation between 24 and 48 hr after wetting of the cysts. Teratogenicity of substances dissolved in the medium is assayed by comparison of average lengths of animals raised for the test period in suspect solution with average lengths of controls. The system is fast, inexpensive, and requires little skill. Brine shrimp are suited to testing industrial wastes, chemical formulations, drugs, and food additives that can be dissolved in water at 25 degrees C. The method appears unsuited to testing the teratogenicity of gases, particulates, very dilute wastes, or natural waters. Cadmium, mercury, lead, zinc, bromoform, n-butylphthalate, 1,2-dichloroethane, nitrobenzene, tetrachloroethylene, toluene, 1,2,4-trichlorobenzene, and 1,1,3-trichloroethane were found teratogenic. Chromium (III), chromium (VI), copper, chlorobenzene, chloroform, dimethyl sulfoxide (DMSO), and phenol were found not teratogenic. Other aquatic organism teratogen test systems are surveyed. PMID:6872918

Kerster, H W; Schaeffer, D J

1983-06-01

139

Investigation of the behavior of VOCs in ground water across fine- and coarse-grained geological contacts using a medium-scale physical model  

SciTech Connect

One of the serious impediments to the remediation of ground water contaminated with volatile organic compounds (VOCs) is that the VOCs are retarded with respect to the movement of the ground water. Although the processes that result in VOC retardation are poorly understood, we have developed a conceptual model that includes several retarding mechanisms. These include adsorption to inorganic surfaces, absorption to organic carbon, and diffusion into areas of immobile waters. This project was designed to evaluate the relative contributions of these mechanisms; by improving our understanding, we hope to inspire new remediation technologies or approaches. Our project consisted of a series of column experiments designed to measure the retardation, in different geological media, of four common ground water VOCs (chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene) which have differing physical and chemical characteristics. It also included a series of diffusion parameters that constrain the model, we compared the data from these experiments to the output of a computational model.

Hoffman, F.; Chiarappa, M.L.

1998-03-01

140

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

141

Enhanced formation of dioxins and furans from combustion devices by addition of trace quantities of bromine  

SciTech Connect

Past pilot-scale experimental studies have shown a dramatic increase in the formation of certain chlorinated products of incomplete combustion (PICs) caused by the addition of trace amounts of bromine (Br). Emissions of trichloroethylene and tetrachloroethylene, generated as PICs from the fuel-lean combustion of methylene chloride, were enhanced by up to 3 orders of magnitude by introducing Br in the form of methylene bromide at a constant halogen molar input rate with a 1:10 Br/chlorine (Cl) molar ratio. The two chlorinated PICs in question are both potential ring growth precursors, which could lead to enhanced formation of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs). The experiments described in this paper expand on this earlier work by examining the effect of trace amounts of Br on the formation of PCDDs/PCDFs, in addition to other chlorinated, brominated, and mixed bromo-chloro organic PICs.

Lemieux, P.M.; Ryan, J.V. [Environmental Protection Agency, Research Triangle Park, NC (United States). Air Pollution Prevention and Control Div.] [Environmental Protection Agency, Research Triangle Park, NC (United States). Air Pollution Prevention and Control Div.

1998-12-31

142

Bioremediation of contaminated groundwater  

DOEpatents

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

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

1995-01-01

143

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

144

Method for detecting toxic gases  

DOEpatents

A method is disclosed which is capable of detecting low concentrations of a pollutant or other component in air or other gas. This method utilizes 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. An electrochemical sensor responds 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. 6 figures.

Stetter, J.R.; Zaromb, S.; Findlay, M.W. Jr.

1991-10-08

145

Bioremediation of contaminated groundwater  

DOEpatents

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

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

1995-01-24

146

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

147

Quarterly sampling of the wetlands along the old F-Area effluent ditch: March 1994  

SciTech Connect

In March 1994, well point water and near surface water (bucket) samples were collected to further characterize tritium and volatile organic compounds (VOC) in the wetlands along the old F-Area effluent ditch south of 643-E (old burial ground). Groundwater flow paths suggest that compounds detected in water table wells around 643-E would migrate towards the old F-Area effluent ditch and Fourmile Branch. Recent analytical results from near surface water sampling in the wetlands that comprise the old F-Area effluent ditch have shown that tritium and small quantities of VOCs are outcropping in the area. Results of the March 1994 sampling event further support findings that tritium and volatile organic compounds originating from 643-E are outcropping in the wetlands near the old F-Area effluent ditch. Six different analytes were detected in the well points at least once at concentrations greater than the method detection limit: d 1,2-dichloroethylene, acetone, methyl ethyl ketone, tetrachloroethylene, trichloroethylene, and tritium. 1,2-dichloroethylene, tetrachloroethylene, trichloroethylene, and tritium were detected at levels above Primary Drinking Water Standards or Maximum Contaminant Levels list. Four analytes, 1,2-dichloroethylene, trichloroethylene, tritium, and vinyl chloride, were detected at least once at concentrations greater than the method detection limit and least once at concentrations above the PDWS or the MCL. Based on differences in tritium concentrations at each location, it was determined that the sampling devices intercepted different groundwater flow paths. This negated direct comparison of analytical results between devices. However, when VOC concentrations measured at each well point and bucket location were normalized, resulting well point and bucket VOC concentrations were comparable in most cases. These results suggest that volatilization losses of VOCs from the buckets were negligible.

Dixon, K.L.; Cummins, C.L.; Rogers, V.A.

1994-05-01

148

Evaluation of exposure to contaminated drinking water and specific birth defects and childhood cancers at Marine Corps Base Camp Lejeune, North Carolina: a case-control study  

PubMed Central

Background Drinking water supplies at Marine Corps Base Camp Lejeune were contaminated with trichloroethylene, tetrachloroethylene, benzene, vinyl chloride and trans-1,2-dichloroethylene during 1968 through 1985. Methods We conducted a case control study to determine if children born during 1968–1985 to mothers with residential exposure to contaminated drinking water at Camp Lejeune during pregnancy were more likely to have childhood hematopoietic cancers, neural tube defects (NTDs), or oral clefts. For cancers, exposures during the first year of life were also evaluated. Cases and controls were identified through a survey of parents residing on base during pregnancy and confirmed by medical records. Controls were randomly sampled from surveyed participants who had a live birth without a major birth defect or childhood cancer. Groundwater contaminant fate and transport and distribution system models provided estimates of monthly levels of drinking water contaminants at mothers’ residences. Magnitude of odds ratios (ORs) was used to assess associations. Confidence intervals (CIs) were used to indicate precision of ORs. We evaluated parental characteristics and pregnancy history to assess potential confounding. Results Confounding was negligible so unadjusted results were presented. For NTDs and average 1st trimester exposures, ORs for any benzene exposure and for trichloroethylene above 5 parts per billion were 4.1 (95% CI: 1.4-12.0) and 2.4 (95% CI: 0.6-9.6), respectively. For trichloroethylene, a monotonic exposure response relationship was observed. For childhood cancers and average 1st trimester exposures, ORs for any tetrachloroethylene exposure and any vinyl chloride exposure were 1.6 (95% CI: 0.5-4.8), and 1.6 (95% CI: 0.5-4.7), respectively. The study found no evidence suggesting any other associations between outcomes and exposures. Conclusion Although CIs were wide, ORs suggested associations between drinking water contaminants and NTDs. ORs suggested weaker associations with childhood hematopoietic cancers. PMID:24304547

2013-01-01

149

Volatile organic compounds detected in vapor-diffusion samplers placed in sediments along and near the shoreline at Allen Harbor Landfill and Calf Pasture Point, Davisville, Rhode Island, March-April 1998  

USGS Publications Warehouse

Volatile organic compounds are present in ground water at the Allen Harbor Landfill and the Calf Pasture Point sites on the former Naval Construction Battalion Center in Davisville, R.I. Vapor-diffusion samplers were used at the two sites during March-April 1998 to identify possible discharge points for contaminants along the shore of Allen Harbor and in two wetland areas near the shore. Results from vapor-diffusion samplers will be used in conjunction with other site information to evaluate proposed ground-water monitoring programs. Volatile organic compounds were detected in 41 of 115 samplers placed along the shoreline at the Allen Harbor Landfill. Trichloroethylene was the principal volatile organic compound detected of eight target compounds. The highest vapor concentration measured exceeded 300,000 parts per billion by volume in an area where TCE was detected in groundwater from nearby monitoring wells. Other chemicals detected in vapor-diffusion samplers included tetrachloroethylene, toluene, and benzene. Concentrations of individual volatile organic compounds were less than 100 parts per billion by volume in most samplers. Volatile organic compounds, principally trichloroethylene, were detected in 7 of 30 samplers placed along the shoreline at Calf Pasture Point; the highest trichloroethylene concentration was 1,900 parts per billion by volume. A trace concentration of tetrachloroethylene was detected in one of the samplers. One of 24 samplers placed in two wetland areas near the shore (suspected discharge areas for ground-water containing volatile organic compounds) detected trichloroethylene at a vapor concentration of 14 parts per billion by volume.

Lyford, F. P.; Kliever, J. D.; Scott, Clifford

1999-01-01

150

A survey of household products for volatile organic compounds  

NASA Astrophysics Data System (ADS)

A total of 1159 common household products were analysed for 31 volatile organic compounds as potential sources of indoor air pollution. The products were distributed among 65 product categories within 8 category classes: automotive products (14.4% of the products); household cleaners/polishes (9.6%); paint-related products (39.9%); fabric and leather treatments (7.9%); cleaners for electronic equipment (6.0%); oils, greases and lubricants (9.6%); adhesive-related products (6.6%); and miscellaneous products (6.1%). The study was conducted in two parts. In the first part, or the original study, the products were reanalysed for methylene chloride and five other chlorocarbons using purge-and-trap gas chromatography/mass spectrometry (GC/MS), and a data base containing the analytical results was developed. Because full mass spectra were taken, the original set of GC/MS data also contained information regarding other volatile chemicals in the products. However, this additional data was not reported at that time. In the second part of the study, the GC/MS data were reanalysed to determine the presence and concentrations of an additional 25 volatile chemicals. The 31 chemicals included in both parts of this study were: carbon tetrachloride; methylene chloride; tetrachloroethylene; 1,1,1-trichloroethane; trichlorethylene; 1,1,2-tricholorotrifluoroethane; acetone; benzene; 2-butanone; chlorobenzene; chloroform; cyclohexane; 1,2-dichloroethane; 1,4-dioxane; ethylbenzene; n-hexane; d-limonene; methylcyclohexane; methylcyclopentane; methyl isobutyl ketone; n-nonane; n-octane; ?-pinene; propylene oxide; styrene; 1,1,2,2-tetrachloroethane; tetrahydrofuran; toluene; m-mxylene; o-xylene; and p-xylene. Of the 31 chemicals, toluene, the xylenes and methylene chloride were found to occur most frequently—in over 40% of the products tested. Chemicals that were typically found in relatively high concentrations in the samples (i.e. greater than 20% w/w) included acetone, 2-butanone, hexane, methylene chloride, tetrachloroethylene, toluene, 1,1,1-trichloroethane, trichloroethylene, 1,1,2-trichlorotrifluoroethane and the xylenes. Chlorobenzene, d-limonene, 1,1,2,2-tetrachloroethane, n-nonane and styrene were not found in any of the products at or above the 0.1% level. In all, 935 of the products contained one or more of the target solvents at levels greater than 0.1%. The resulting data base contains information regarding the 1159 products, such as origin, cost, container type, lot number, etc., as well as quantitative information for each of the 31 chemicals. The frequency of occurrence and average concentrations for the target chemicals are summarized for each of the product classes.

Sack, Thomas M.; Steele, David H.; Hammerstrom, Karen; Remmers, Janet

151

Dodecyl sulfate-hydrotalcite nanocomposites for trapping chlorinated organic pollutants in water.  

PubMed

A series of hybrid organic-inorganic nanocomposite materials was synthesized by three different procedures using sodium dodecyl sulfate (DDS) and magnesium-aluminum layered double hydroxide (Mg/Al LDH with a Mg/Al molar ratio of 2 to 5). Both the pH of the exchange medium (6.5 to 10) and the Mg/Al molar ratio of the LDH affected the basal spacing, the content of DDS retained and the orientation of the DDS chains within the interlamellar space. For LDH with higher charge density (Mg/Al=2 and 3), DDS molecules likely formed a perpendicular monolayer within the LDH interlayer and the solution pH had little effect on the basal spacing, with a mean and standard deviation of 25.5+/-0.4 A. However, for LDH with lower charge density (Mg/Al=4 and 5), DDS molecules more likely formed an interpenetrating bilayer, and the basal spacing significantly increased with increasing pH, with a mean and standard deviation of 32.7+/-5.2 A. Sorption of trichloroethylene and tetrachloroethylene by DDS-LDH varied with synthesis conditions, LDH type and DDS configuration in the interlayer. DDS-Mg(3)Al-LDH had the highest affinity for both trichloroethylene and tetrachloroethylene in water, either comparable to or as much as four times higher than other clay-derived sorbents, followed by DDS-Mg(4)Al-LDH and DDS-Mg(5)Al-LDH. DDS-Mg(2)Al-LDH had the lowest sorption affinity although the highest amount of DDS. The pH of the exchange solution also affected the amount of DDS retained by the LDH as well as the sorption efficiency. Mg(3)Al-LDH has a charge equivalent area of 32.2 A(2)/charge, which allows the formation of optimal DDS configuration within its interlayer, thus resulting in the highest affinity for the chlorinated compounds. The DDS-Mg/Al-LDHs can be easily synthesized either ex situ or in situ at low temperature, indicating the feasibility of practical applications. The results obtained by controlling the synthesis procedure suggest that different arrangements of DDS molecules in the LDH interlayers can be obtained and optimized for the sorption of specific sorbates. PMID:15144837

Zhao, Hongting; Nagy, Kathryn L

2004-06-15

152

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

153

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

154

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

155

Characterization and simulation of fate and transport of selected volatile organic compounds in the vicinities of the Hadnot Point Industrial Area and landfill: Chapter A Supplement 6 in Analyses and historical reconstruction of groundwater flow, contaminant fate and transport, and distribution of drinking water within the service areas of the Hadnot Point and Holcomb Boulevard Water Treatment Plants and vicinities, U.S. Marine Corps Base Camp Lejeune, North Carolina  

USGS Publications Warehouse

This supplement of Chapter A (Supplement 6) describes the reconstruction (i.e. simulation) of historical concentrations of tetrachloroethylene (PCE), trichloroethylene (TCE), and benzene3 in production wells supplying water to the Hadnot Base (USMCB) Camp Lejeune, North Carolina (Figure S6.1). A fate and transport model (i.e., MT3DMS [Zheng and Wang 1999]) was used to simulate contaminant migration from source locations through the groundwater system and to estimate mean contaminant concentrations in water withdrawn from water-supply wells in the vicinity of the Hadnot Point Industrial Area (HPIA) and the Hadnot Point landfill (HPLF) area.4 The reconstructed contaminant concentrations were subsequently input into a flow-weighted, materials mass balance (mixing) model (Masters 1998) to estimate monthly mean concentrations of the contaminant in finished water 5 at the HPWTP (Maslia et al. 2013). The calibrated fate and transport models described herein were based on and used groundwater velocities derived from groundwater-flow models that are described in Suárez-Soto et al. (2013). Information data pertinent to historical operations of water-supply wells are described in Sautner et al. (2013) and Telci et al. (2013).

Jones, L. Elliott; Suárez-Soto, René J.; Anderson, Barbara A.; Maslia, Morris L.

2013-01-01

156

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

2011-01-01

157

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

158

Ranking the carcinogenic hazards of occupational exposures: Exposure-Potency Index (EPI) values for nine volatile industrial chemicals  

SciTech Connect

Employers, employees, and occupational health professionals need a simple index to rank carcinogens according to their potential danger at exposure levels which are commonly encountered in workplaces. We describe such an index, the Exposure-Potency Index (EPI). This simple proportion, dose level (mg/kg body weight/day) to which workers are permitted to be exposed/cancer-causing dose (mg/kg body weight/day) in test animals, permits comparisons among carcinogens. We have calculated this index for inhalation exposures to 1,3-butadiene, 1,2-dibromo-3-chloropropane (DBCP), 1,2-dibromoethane (EDB), ethylene oxide, formaldehyde, methylene chloride, propylene oxide, tetrachloroethylene (perchloroethylene), and trichloroethylene (TCE). The permitted worker exposure levels have frequently been close to the levels which induce tumors in laboratory animals. More recently, Permissible Exposure Limits (PEL's) for for some chemicals have been markedly reduced, and this is reflected in lowered EPI values. Combining EPI values with information on the numbers of exposed workers provides a simple means of identifying and ranking dangers to populations of workers.

Hooper, K.; Gold, L.S.

1986-01-01

159

Analysis of BTEX and chlorinated solvents in meconium by headspace-solid-phase microextraction gas chromatography coupled with mass spectrometry.  

PubMed

Meconium is the earliest stool of newborns, and is a complex matrix that reflects the degree of exposure of the fetus to xenobiotics. To investigate fetal exposure to volatile organic compounds, an analytical method was developed to identify and quantify BTEX (benzene, toluene, ethylbenzene, and o,m,p-xylene) and two chlorinated solvents (trichloroethylene and tetrachloroethylene) in meconium. Headspace-solid-phase microextraction coupled with gas chromatography-mass spectrometry was selected because it is simple, sensitive, can be automated, and requires no extensive sample preparation. Several extraction variables were optimized (fiber type, incubation time, temperature of fiber, and use of salt). Because meconium is a complex matrix, quantification by SPME was considered carefully because of potential interference, for example competitive adsorption. Calibration in water was compared with calibration in meconium using external and internal methods (with isotope-labeled compounds). In meconium, limits of quantification were determined to be in the range 0.064-0.096 ng g(-1) for the investigated compounds. All target compounds were determined in "real-case" meconium samples. PMID:24838489

Meyer-Monath, Marie; Beaumont, Jérôme; Morel, Isabelle; Rouget, Florence; Tack, Karine; Lestremau, Francois

2014-07-01

160

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

161

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] [Tulane Univ., New Orleans, LA (United States). Dept. of Chemical Engineering

1996-08-01

162

In planta passive sampling devices for assessing subsurface chlorinated solvents.  

PubMed

Contaminant concentrations in trees have been used to delineate groundwater contaminant plumes (i.e., phytoscreening); however, variability in tree composition hinders accurate measurement of contaminant concentrations in planta, particularly for long-term monitoring. This study investigated in planta passive sampling devices (PSDs), termed solid phase samplers (SPSs) to be used as a surrogate tree core. Characteristics studied for five materials included material-air partitioning coefficients (Kma) for chlorinated solvents, sampler equilibration time and field suitability. The materials investigated were polydimethylsiloxane (PDMS), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyoxymethylene (POM) and plasticized polyvinyl chloride (PVC). Both PDMS and LLDPE samplers demonstrated high partitioning coefficients and diffusivities and were further tested in greenhouse experiments and field trials. While most of the materials could be used for passive sampling, the PDMS SPSs performed best as an in planta sampler. Such a sampler was able to accurately measure trichloroethylene (TCE) and tetrachloroethylene (PCE) concentrations while simultaneously incorporating simple operation and minimal impact to the surrounding property and environment. PMID:24268175

Shetty, Mikhil K; Limmer, Matt A; Waltermire, Kendra; Morrison, Glenn C; Burken, Joel G

2014-06-01

163

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

164

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

165

Uptake and fate of organohalogens from contaminated groundwater in woody plants  

SciTech Connect

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

Sytsma, L.; Mulder, J.; Schneider, J. [Argonne National Lab., IL (United States)] [and others

1997-12-31

166

Spatial distribution characteristics of volatile halogenated hydrocarbons in unsaturated zone of Xiaodian sewage irrigation area, Taiyuan, China.  

PubMed

Sewage irrigation is one of the best options to reduce the stress on limited fresh water and to meet the nutrient requirement of crops. Environment pollution caused by volatile halogenated hydrocarbons (VHCs) associated with sewage irrigation has received increasing attention due to the toxicological importance in ecosystem. The aim of this study was to discuss the spatial distribution characteristics of VHCs in unsaturated zone under sewage irrigation and their migration in the environment. Soil samples were collected from XiaoDian district of TaiYuan city and measured for the major VHCs including of chloroform (CHCl3), tetrachloromethane (CCl4), trichloroethylene (C2HCl3), tetrachloroethylene(C2Cl4), pentachlorobenzene (C6HCl5), hexachlorobenzene (C6Cl6). Results showed that VHCs were accumulated in the unsaturated zone with long-term sewage irrigation. The contents of VHCs in the unsaturated zone of the study area were 34, 2, 3, 1.5, 8.3, 4.8 times higher than the background value respectively. Soils with long-term irrigation of sewage showed higher contents of VHCs than that with short-term irrigation of sewage. Not only the irrigation time, soil physical properties (e.g. soil texture) also played an important role on VHCs accumulation in soil. PMID:25193606

Liao, Yuan; Ma, Teng; Cui, Yahui; Qi, Zhichong

2014-12-01

167

Near-Infrared (NIR) Study of Hydrogen Bonding of Methanol Molecules in Polar and Nonpolar Solvents: An Approach from Concentration-Dependent Molar Absorptivity.  

PubMed

Differences in the hydrogen-bonding states of methanol in polar and nonpolar solvents were studied by using the first overtone of O-H stretching vibrations observed in the near-infrared (NIR) band ranging from 7500 to 6000 cm(-1). To eliminate the absorption of solvents, NIR-inactive nonpolar solvents carbon tetrachloride (CCl4) and tetrachloroethylene (C2Cl4) were chosen, along with deuterium-substituted polar solvents acetone-d6, acetonitrile-d3, 1,4-dioxane-d8, and tetrahydrofuran (THF)-d8. The changes in the hydrogen-bonding states of methanol during mixing with the solvents were estimated using the extended molar absorption spectrum, which was defined as the concentration difference. The extended molar absorption spectra in different concentrations were decomposed into a finite number of independent factors using a multivariate curve resolution-alternating least squares calculation. Two and three such factors were sufficient to reproduce the extended molar absorption spectra for the nonpolar and polar solvents, respectively. The detailed assignments of each factor were estimated using the calculated loadings and scores. A similarity analysis was also applied to the extended molar absorption spectra of methanol and effectively quantified the deviation from the spectrum of pure methanol. The methanol and solvent affinities were also compared. PMID:25198653

Mikami, Yuho; Ikehata, Akifumi; Hashimoto, Chihiro; Ozaki, Yukihiro

2014-10-01

168

Development of a method for assessing the toxicity of volatile organic contaminants (VOCs) to soil biota  

SciTech Connect

A method was developed to assess the toxicity of VOCs to plants and earthworms (survival of Eisenia foetida). The procedures followed were based on Greene et al. Gas samples for head space analyses were removed, at test initiation a termination, through a bulkhead fitting in the lid equipped with septa. Treatment levels were prepared, at low temperature to minimize volatilization, by spiking a soil sample with the compound of interest and then serially diluting it with clean soil. Root elongation tests were conducted on filter paper supported by 70 mesh silica sand spiked with the volatile of interest. Soils were then inundated with water, shaken with heating, and the headspace reanalyzed for the total contaminant concentration in the test system (total equals headspace plus adsorbed). Enclosing the seeds and worms in containers did not appear to have detrimental effects. VOCs tested included benzene, xylene, toluene, ethylbenzene, tetrachloroethylene, and 1,1,2-trichloroethylene. Each test was repeated three times with different batches of soil, seed lots and worms from different colonies. Endpoints derived based on nominal and measured concentrations included: NOEC, LOEC, LC{sub 50} and LC{sub 25} for earthworm mortality and EC{sub 50} and EC{sub 25} for emergence and root elongation.

Cureton, P.M. [Environment Canada, Ottawa, Ontario (Canada). Evaluation and Interpretation Branch; Lintott, D.; Balch, G.; Goudey, S. [HydroQual Labs. Ltd., Calgary, Alberta (Canada)

1994-12-31

169

Plume and lithologic profiling with surface resistivity and seismic tomography.  

PubMed

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. PMID:15819938

Watson, David B; Doll, William E; Gamey, T Jeffrey; Sheehan, Jacob R; Jardine, Philip M

2005-01-01

170

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

171

Development of CFC-Free Cleaning Processes at the NASA White Sands Test Facility  

NASA Technical Reports Server (NTRS)

The NASA White Sands Test Facility (WSTF) is developing cleaning and verification processes to replace currently used chlorofluorocarbon-113- (CFC-113-) based processes. The processes being evaluated include both aqueous- and solvent-based techniques. The presentation will include the findings of investigations of aqueous cleaning and verification processes that are based on a draft of a proposed NASA Kennedy Space Center (KSC) cleaning procedure. Verification testing with known contaminants, such as hydraulic fluid and commonly used oils, established correlations between nonvolatile residue and CFC-113. Recoveries ranged from 35 to 60 percent of theoretical. WSTF is also investigating enhancements to aqueous sampling for organics and particulates. Although aqueous alternatives have been identified for several processes, a need still exists for nonaqueous solvent cleaning, such as the cleaning and cleanliness verification of gauges used for oxygen service. The cleaning effectiveness of tetrachloroethylene (PCE), trichloroethylene (TCE), ethanol, hydrochlorofluorocarbon-225 (HCFC-225), tert-butylmethylether, and n-Hexane was evaluated using aerospace gauges and precision instruments and then compared to the cleaning effectiveness of CFC-113. Solvents considered for use in oxygen systems were also tested for oxygen compatibility using high-pressure oxygen autoignition and liquid oxygen mechanical impact testing.

Beeson, Harold; Kirsch, Mike; Hornung, Steven; Biesinger, Paul

1995-01-01

172

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

2008-08-01

173

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

174

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

SciTech Connect

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 using ethanol and 2,2-dimethyl-3-pentanol as the non-partitioning and partitioning tracers, respectively. The concentration breakthrough curves for the tracers exhibited significant chromatographic separation due to partitioning of the 2,2-dimethyl-3-pentanol into the PCE. Because of the unique streamline distribution generated by the VCW systems, injected solutions did not sweep through the entire contaminated pore volume, which resulted in less than 100% detection of the spilled PCE. However, multiple tests along the borehole of the well were used to delineate the vertical profile of PCE residual saturation. Three food-grade surfactants were used to remediate the spilled PCE.

Chen, L.; Knox, R.C.

1997-12-01

175

Monitoring polycyclic aromatic hydrocarbons in seawaters and wastewaters using a dispersive liquid-liquid microextraction method.  

PubMed

An evaluation has been made of a dispersive liquid-liquid microextraction (DLLME) procedure for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in different environmental waters including seawaters and wastewaters, using gas-chromatography (GC) with flame-ionization detection (FID). The optimized method requires 18 microL of the extractant solvent tetrachloroethylene (C2Cl4), 1 mL of acetonitrile as dispersive solvent, and 5 mL of aqueous sample. After centrifugation (5 min), 2 microL of the obtained micro-droplet containing the extracted PAHs, which varied from - 15 microL for seawaters to - 9 microL for wastewaters, is directly injected in the GC-FID. The performance of the method is characterized for average extraction efficiencies of 99.0% and 98.1% when analysing real seawaters and wastewaters, respectively, at low spiked levels (3 ng x mL(-1)); and average precision values of 8.4% as relative standard deviation. The performance of the method was also compared with conventional liquid-liquid extraction. The DLLME calibrations have been obtained in different aqueous matrices to thoroughly evaluate the matrix effect. The application of the joint-confidence ellipse F-test showed that seawaters can be simply analysed using DLLME calibrations obtained in the laboratory using deionized water. However, important caution must be taken into account when dealing with wastewater, because of matrix effects. PMID:23837310

Ramos-Dorta, Carmen V; Pino, Verónica; Afonso, Ana M

2013-01-01

176

East Traffic Circle Landfill closure report  

SciTech Connect

This report presents the results of the investigation and cleanup of the East Traffic Circle Landfill (ETCL), an inactive landfill located in the east-central portion of the main site of Lawrence Livermore National Laboratory. The old landfill site was uncovered by construction workers during utility-line trenching on July 19, 1984. The uncovered debris was surveyed with radiation detection instruments, showed no radioactivity, and was found to consist primarily of metal shavings and broken bottles. An initial soil sample was taken and analyzed for metals and volatile organic compounds. Only copper, lead, and zinc were detected in some samples at levels exceeding the state hazardous waste designations. Shallow soils generally showed little (less than 0.1 ppM) volatile halogenated and non-halogenated volatile organic chemical contamination; however, a sample collected beneath 20 partially crushed metal drums showed 11 ppM of trichloroethylene (TCE) and 50 ppM of tetrachloroethylene (PCE). Soils from 21 to 51 feet beneath the drums showed TCE and PCE concentrations approaching 1 ppM each. The East Traffic Circle Landfill area was generally excavated to a depth of 5 to 7 feet below grade and to 10 or more feet in the vicinity of 160-plus capacitors. The 13,971 cubic yards of excavated soil and debris were hauled from the LLNL site by registered haulers and disposed of at state-permitted hazardous waste disposal sites. Construction activities resumed in the area after the landfill was backfilled.

McConachie, W.A.; Como, J.P.; Carpenter, D.W.; Ragaini, R.C.

1986-01-31

177

Metallurgical Laboratory Hazardous Waste Management Facility groundwater monitoring report: First quarter 1992  

SciTech Connect

During first quarter 1992, 18 groundwater monitoring wells of the AMB series at the Metallurgical Laboratory Hazardous Waste Management Facility (Metlab HWMF) at Savannah River Plant were visited for sampling. Groundwater samples were analyzed for certain heavy metals, indicator parameters, radionuclides, volatile organic compounds, and other constituents. This report describes the results that exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) and the Savannah River Site flagging criteria during the quarter. Tetrachloroethylene exceeded the PDWS in wells AMB 4A, 5, and 7A; trichloroethylene exceeded the PDWS in wells AMB 4A, 4B, 4D, 5, and 7A; and total alpha-emitting radium (radium-224 and radium-226) exceeded the PDWS in well AMB 5. Total organic halogens exceeded the Flag 2 criterion in wells AMB 4A, 5, 6, 7A, 7B, and IODD; manganese was elevated in wells AMB 4D and TODD; iron was elevated in well AMB TODD; and pH was elevated in well AMB 10A.

Thompson, C.Y.

1992-06-01

178

Well venting and application of passive soil vapor extraction at Hanford and Savannah River  

SciTech Connect

At the Hanford and Savannah River Sites, wells with open intervals in the unsaturated zone have been observed to {open_quotes}breathe{close_quotes}, i.e., to inhale ambient air from the surface and to exhale soil gas to the atmosphere. This breathing results primarily from the difference in pressure that develops between the soil pressure near the open interval of a well and the barometric pressure. Volatile organic compounds (VOC) have been identified at both Hanford (carbon tetrachloride) and Savannah River (trichloroethylene and tetrachloroethylene). Passive vapor extraction (PVE) refers to the enhancement and application of this natural breathing phenomenon as a remediation method for increased VOC removal rates from the unsaturated zone. Passive vapor extraction is proposed as a complementary technology to be used with active vapor extraction (AVE). The AVE system would be used to extract soil gas from the high VOC concentration, highly permeable zones. The enhanced PVE would be used to address those zones of lower VOC concentration and those zones where extraction is limited by mass transfer and diffusion. The primary advantages of PVE application are low capital costs and minimal operating costs. This combination allows for many small PVE systems to be placed on individual wells and for the systems to operate for the extended periods of time associated with remediation of sites in which soil-gas transport is diffusion limited.

Rohay, V.J. [Westinghouse Hanford Co., Richland, WA (United States); Rossabi, J.; Looney, B. [Westinghouse Savannah River Co., Aiken, SC (United States); Cameron, R.; Peters, B. [Ebasco Services, Inc., New York, NY (United States)

1993-09-01

179

Ranking the potential carcinogenic hazards to workers from exposures to chemicals that are tumorigenic in rodents.  

PubMed Central

For 41 chemicals there exist both reasonable data on carcinogenic potency in experimental animals and also a defined Permissible Exposure Level (PEL), which is the upper limit of legally permissible chronic occupational exposure for U.S. workers. These 41 agents are ranked by an index that compares the permitted chronic human exposure to the chronic dose rate that induces tumors in 50% of laboratory animals. This index, the Permitted Exposure/Rodent Potency index, or PERP, does not estimate absolute risks directly, but rather suggests the relative hazards that such substances may pose. The PERP values for these 41 substances differ by more than 100,000-fold from each other. The PERP does not take into account the actual level of exposure or the number of exposed workers. Nevertheless, it might be reasonable to give priority attention to the reduction of allowable worker exposures to substances that appear most hazardous by this index and that some workers may be exposed to full-time near the PEL. Ranked by PERP, these chemicals are: ethylene dibromide, ethylene dichloride, 1,3-butadiene, tetrachloroethylene, propylene oxide, chloroform, formaldehyde, methylene chloride, dioxane, and benzene. PMID:3447901

Gold, L S; Backman, G M; Hooper, N K; Peto, R

1987-01-01

180

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

181

Recovery of some common solvents from protective clothing breakthrough indicator pads by microwave-solvent extraction and gas chromatography.  

PubMed

The efficiency of solvent adsorption using Permea-Tec general solvent pads, used for the detection of chemical breakthrough of protective clothing, was determined for methanol, acetone, ethyl methyl ketone, trichloroethylene (TriCE), tetrachloroethylene (TetCE), toluene, m-xylene, and D-limonene. Known volumes of single or mixed solvents were added to pads in the range 0.2-5.0 microliters (0.16-8.13 micrograms). After microwave-solvent extraction (ME) into hexan-1-ol, the samples (0.5-3.0 microliters) of the filtered and extracted solutions were analyzed by gas chromatography. All solvents exhibited > 97% adsorption on the pads at spiking levels of 0.48-0.98 microgram for each solvent. The solvent recovery for the system was calculated for each solvent, with solvents with boiling points below 110 degrees C showing recoveries of > 90%, and with solvents with boiling points above 110 degrees C showing recoveries from 80 to 90%. The recovery precision was good (RSD < or = 4%) for all solvents over the range 1.0-2.5 microliters of applied solvents to pads for ME and 1.0 microliter of extracted solutions for GC analysis. PMID:10736878

Vo, E; Berardinelli, S P; Hall, R C

1999-06-01

182

Site characterization program at the radioactive waste management complex of the Idaho National Engineering Laboratory  

SciTech Connect

The Radioactive Waste Management Complex (RWMC) Site Characterization Program is a continuation of the Subsurface Investigation Program (SIP). The scope of the SIP has broadened in response to the results of past work that identified hazardous as well as radionuclide contaminants in the subsurface environment and in response to the need to meet regulatory requirements. Two deep boreholes were cored at the RWMC during FY-1988. Selected sediment samples were submitted for Appendix IX of 40 CFR Part 264 and radionuclide analyses. Detailed geologic logging of archived core was initiated. Stratigraphic studies of the unsaturated zone were conducted. Studies to determine hydrologic properties of sediments and basalts were conducted. Geochemical studies and analyses were initiated to evaluate contaminant and radionuclide speciation and migration in the Subsurface Disposal Area (SDA) geochemical environment. Analyses of interbed sediments in boreholes D15 and 8801D did not confirm the presence of radionuclide contamination in the 240-ft interbed. Analyses of subsurface air and groundwater samples identified five volatile organic compounds of concern: carbon tetrachloride, trichloroethylene, 1,1,1-trichloroethane, chloroform, and tetrachloroethylene. 33 refs., 5 figs., 2 tabs.

McElroy, D.L.; Rawson, S.A.; Hubbell, J.M.; Minkin, S.C.; Baca, R.G.; Vigil, M.J.; Bonzon, C.J.; Landon, J.L.; Laney, P.T.

1989-07-01

183

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

PubMed

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

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

2012-05-01

184

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

185

Surface changes in well-casing pipe exposed to high concentrations of organics in aqueous solution. Special report  

SciTech Connect

This preliminary study was undertaken to assess how the surface structural characteristics of four common well casing materials-polyvinyl chloride (PVC), Teflon (polytetrafluoroethylene, PTFE), stainless steel 304 (SS304) and stainless steel 316 (SS316)-are affected by exposure to an aqueous solution containing tetrachloroethylene, toluene, p-dichlorobenzene and 0-dichlorobenzene in concentrations near their solubility. Casing samples that had been exposed to a test solution for 1 week, 1 month and 6 months were examined with a scanning electron microscope (SEM) and compared with control samples placed in well water for an equivalent time period. Pieces of casing that had not been placed in any aqueous solution were also examined and are assumed to be representative of the initial structure of the casing's surface. These organics are of concern at hazardous waste sites, where they often occur in ground water. The observations indicate that the surface characteristics of PVC, SS316 and SS304 did not change when exposed to the organic aqueous solution. The surface variability and lack of distinguishing features at high magnification made it difficult to tell if the PTFE surface had changed. However, no obvious changes (swelling, pitting etc.) were seen.

Taylor, S.; Parker, L.

1990-03-01

186

Adapting the Bruel and Kjaer Multi-gas Monitor Type 1302 to measure selected volatile organic chemicals (VOCs) in soil  

SciTech Connect

The Bruel and Kjaer Multi-gas Monitor Type 1302 can simultaneously measure up to five different volatile organic chemicals (VOCS) in a single air sample by using optical filters combined with a photo acoustic detection method. The monitor has previously been validated to measure VOCs in water, by purging aqueous samples into Tedlar{trademark} bags. The method used to measure VOCs in water has been adapted for use with soil. Soil samples are diluted with water and VOCs are purged with air from the resulting slurry into a Tedlar{trademark} bag. The contents of the Tedlar{trademark} bag are then analyzed with the multi-gas monitor. Data have been generated for the measurement of chloroform, trichloroethylene, tetrachloroethylene, carbon tetrachloride, and acetone. The method is linear for these VOCs from approximately 1 to at least 128 {mu}g/g of soil (ppM). There is no measurable cross interference of these VOCs with each other when more than one is present in a single soil sample. Contaminants other than those being measured may interfere with detection of these VOCS, so some prior site characterization is required. The method is easy to perform, rapid, reproducible, and sensitive enough for field screening applications.

Palausky, M.A.; Waters, L.C.; Counts, R.W.; Jenkins, R.A.

1995-04-01

187

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

188

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

189

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

190

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

191

Modeling acute and chronic toxicity of nonpolar narcotic chemicals and mixtures to Ceriodaphnia dubia.  

PubMed

The response of the daphnid Ceriodaphnia dubia to six widely used industrial chemicals acting through nonpolar narcosis and a mixture was determined. Toxicological effect levels were based on reasonably steady-state, measured concentrations. Reproductive IC50S were 149 microM benzene, 82 microM trichloroethylene, 35 microM toluene, 31 microM ethylbenzene, 26 microM m-xylene, and 4 microM tetrachloroethylene. A QSAR describing 2-day LC50S as a function of log Kow accounted for 90.97% of the variation in response across chemical. A similar QSAR for chronic effects on reproduction accounted for 78.92%. Mixtures of benzene, trichloroethylene, and toluene had effects at concentrations below their individual LOELs. Observed effects of 20/24 mixtures tested fell within the 95% prediction interval for a concentration-addition model of joint action derived from tests with individual components. However, the observed response differed significantly from the predictive relationship. In general, the predictive relationship overestimated mixture toxicity. Fitted relationships reduced observed error by as much as 82% compared to the predictive model. PMID:9515086

Niederlehner, B R; Cairns, J; Smith, E P

1998-02-01

192

Seed germination and root elongation as indicators of exposure of wetland seedlings to metals  

SciTech Connect

Wetland ecosystems have often been impacted by the addition of hazardous waste materials. Methods are needed to evaluate the effect of these substances on wetland ecosystems and the organisms within them. This study evaluates the response of various wetland plant species to representative contaminants (cadmium, nickel, atrazine, anthracene, and tetrachloroethylene). Species tested include Caphalanthus occidentalis (buttonbush), Saururus cernuus (lizard`s tail), Liquidambar styraciflua (sweetgum), Sparganium americanum (bur-reed), and Fraxinus pennsylvanica (green ash). To the authors` knowledge these species have rarely if ever been used in toxicological assays. The endpoints used are germination and root elongation. Preliminary studies using a petri dish system have shown decreased germination at the highest metal concentration (50mg/L) and decreased root elongation in the higher metal concentrations (10, 25, and 50mg/L). Interference from the carrier was observed in the organic tests. Root elongation studies using the metals are being continued using tubes with various sand and vermiculite mixes into which freshly germinated seeds are placed. Species with the best responses will be tested in the field at the Savannah River Site, SC, and also with fuel oil. Lettuce (Lactuca saliva) and radish (Raphanus sativus) are being tested alongside the wetland species as reference organisms for which tests are well established.

Sutton, H.D.; Stokes, S.L.; Hook, D.D.; Klaine, S.J. [Clemson Univ., Pendleton, SC (United States)

1995-12-31

193

Gas-solid alkali destruction of volatile chlorocarbons  

SciTech Connect

Many chlorocarbons are environmental dangers and health hazards. The simplest perchlorinated hydrocarbon, carbon tetrachloride, is near the top of the list of hazardous compounds. Carbon tetrachloride was used as a cleaning fluid, solvent, and fire-extinguishing agent. The nuclear and defense complexes also employed great quantities of carbon tetrachloride and other chlorocarbons as cleaning and degreasing agents. Many sites nationwide have underground chlorocarbon contamination plumes. Bulk chlorocarbon inventories at many locations await treatment and disposal. Often the problem is compounded by the chlorocarbon being radioactively contaminated. Waste inventory and groundwater contamination problems exist for many other chlorocarbons, especially methylene chloride, chloroform, and tri- and tetrachloroethylene. In this work solid soda lime (a fused mixture of approximately 95% CaO and 5% NaOH in a coarse, granulated form) at 350 C to 400 C acts as the hydrolyzing degradation, and off-gas scrubbing medium. Within soda lime CO{sub 2} and HCl from hydrolysis and degradation convert immediately to calcium and sodium chlorides and carbonates, with water vapor as a volatile byproduct.

Foropoulos, J. Jr.

1995-12-01

194

A paired comparison between human skin and hairless guinea pig skin in vitro permeability and lag time measurements for 6 industrial chemicals.  

PubMed

The purpose of the present study was to measure and compare permeability coefficients (k(p)) and lag times (tau) in human skin and hairless guinea pig (HGP) skin. Paired experiments employed heat-separated epidermal membranes from human and HGP sources mounted on static in vitro diffusion cells. Infinite-dose, saturated aqueous solutions of 6 industrial chemicals were used as donors: aniline, benzene, 1,2- dichloroethane, diethyl phthalate, naphthalene, and tetrachloroethylene. No significant differences were found between human and HGP skin for either k(p) or tau for any of these chemicals (p >or= .24). HGP vs. human k(p) measurements, and HGP vs. human tau measurements, were highly correlated. For k(p), the slope of the linear correlation was close to unity (1.080 +/- 0.182) and the intercept close to 0 (0.015 +/- 0. 029 cm/h), with a correlation coefficient (r(2)) = 0.898. For tau, the slope was also close to unity (0.818 +/- 0.030) and the intercept close to 0 (-0.014 +/- 0.023 h), with r(2) = 0.994. These results suggest that HGP skin may serve as an excellent surrogate for human skin in in vitro dermal penetration studies. PMID:19552540

Frasch, H Frederick; Barbero, Ana M

2009-01-01

195

Health assessment for the Transicoil, Inc. (Zone 12) North Penn Area Site, Worchester, Pennsylvania, Region 3. CERCLIS No. PAD057152365. Preliminary report  

SciTech Connect

The Transicoil Inc. (Zone 12) North Penn Area Site consists of a manufacturing site for DC and synchro electric motors for commercial and defense uses. An on-site underground storage tank was used for waste oil and hazardous substances. On-site cesspools were used for sanitary waste disposal. Identified contaminants of concern to data include trichloroethylene (TCE), 1,1,1-trichloroethane, tetrachloroethylene (PCE), cis-1,2-dichloroethylene, 1,1-dichloroethane, and 1,1-dichloroethylene in well water and TCE, PCE, and 1,1,1-trichloroethane in soil. 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 ingestion of contaminated groundwater, surface water, or other materials or of plants or animals which have accumulated contaminants from the site; contaminated soil ingestion by children; inhalation of compounds volatilized from contaminated groundwater during household uses, of contaminants volatilized from the site, or of contaminants carried in reentrained dust; and dermal contact with contaminated groundwater, surface water, soil, or other materials.

Not Available

1988-09-29

196

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

USGS Publications Warehouse

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

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

2012-01-01

197

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

2011-10-01

198

Effect of geochemical conditions on fate of organic compounds in groundwater  

NASA Astrophysics Data System (ADS)

In situ microcosms were successfully used to study the degradation of a range of organic compounds in two pristine aquifers, one aerobic (Vejen) and one anaerobic (Villa Farm). Degradation and sorption behavior in the laboratory column microcosms packed with Villa Farm sediment was very similar to that in the in situ microcosms. However, when the columns were packed with quartz and equilibrated with aerated Villa Farm groundwater, behavior mirrored that at Vejen, indicating that oxygen rather than sediment or groundwater composition was the critical parameter. The aromatic and polyaromatic compounds (benzene, toluene, o-xylene, naphthalene) degraded under aerobic conditions only. The organochlorine compounds (trichloroethylene, tetrachloroethylene, 1,1,1-trichloroethane, 1,4-dichlorobenzene and 1,2-dichlorobenzene) showed little or no sign of degradation either aerobically or anaerobically. Interpretation of the data was complicated by strong sorption to the Villa Farm sediment but tetrachloromethane, nitrobenzene, and o-nitrophenol appeared to degrade under anaerobic conditions only. Phenol degraded rapidly under both sets of conditions.

Higgo, J. J. W.; Nielsen, P. H.; Bannon, M. P.; Harrison, I.; Christensen, T. H.

1996-06-01

199

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

PubMed

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(-3) cm/s. In contrast to this, the release of 20 drums of coal tar (rho(D)= 1061 kg/m(3), micro(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. PMID:17335479

Gerhard, Jason I; Pang, TiWee; Kueper, Bernard H

2007-01-01

200

Final disposal of VOCs from industrial wastewaters  

SciTech Connect

Vapor phase carbon adsorption followed by spent carbon regeneration and catalytic oxidation were evaluated as methods for disposal of volatile organic compounds (VOCs) released from industrial wastewaters during treatment operations such as aeration, air-stripping and aerobic biodegradation. Adsorptive capacities and breakthrough characteristics for eight VOCs found in many hazardous landfill leachates and contaminated groundwater were compared for selection of the best adsorbent and optimum treatment conditions. Coconut shell-based activated carbons exhibited higher VOC loading capacities than coal-based carbons, fiber carbon, molecular sieve and zeolite. Steam and hot nitrogen were both effective for regeneration of the spent carbon. A small quantity of adsorbates left in the regenerated carbon did not result in immediate VOC breakthrough in the next cycle adsorption treatment. Catalytic oxidation was found to be an attractive alternative for VOC disposal. Using a new commercial catalyst developed for destruction of halogenated organic compounds, even stable VOCs such as trichloroethylene and tetrachloroethylene were completely destroyed at <350[degrees]C when oxidation was conducted at a space velocity of 17000/hr. 25 refs., 10 figs., 10 tabs.

Ying, W.; Bonk, R.R.; Hannam, S.C. (Occidential Chemical Corp., Grand Island, NY (United States)); Qi-dong Li (Fudan Univ., Shanghai (China))

1994-08-01

201

Research to Support the Determination of Spacecraft Maximum Acceptable Concentrations of Potential Atmospheric Contaminants  

NASA Technical Reports Server (NTRS)

In many ways, the typical approach to the handling of bibliographic material for generating review articles and similar manuscripts has changed little since the use of xerographic reproduction has become widespread. The basic approach is to collect reprints of the relevant material and place it in folders or stacks based on its dominant content. As the amount of information available increases with the passage of time, the viability of this mechanical approach to bibliographic management decreases. The personal computer revolution has changed the way we deal with many familiar tasks. For example, word processing on personal computers has supplanted the typewriter for many applications. Similarly, spreadsheets have not only replaced many routine uses of calculators but have also made possible new applications because the cost of calculation is extremely low. Objective The objective of this research was to use personal computer bibliographic software technology to support the determination of spacecraft maximum acceptable concentration (SMAC) values. Specific Aims The specific aims were to produce draft SMAC documents for hydrogen sulfide and tetrachloroethylene taking maximum advantage of the bibliographic software.

Orr, John L.

1997-01-01

202

VOCs in fixed film processes. I: Pilot studies  

SciTech Connect

Stripping of volatile organic contaminants (VOCs) during wastewater treatment is of concern due to the potential of these compounds to contribute to stratospheric ozone depletion, ground-level smog formation, chronic toxicity to exposed workers, and odors. A study of the fate of volatile organic contaminants (VOCs) in trickling filters (TF) and rotating biological contactors (RBC) was performed. Of the target compounds investigated, tetrachloroethylene was volatilized to the greatest extent, while 1,1,2,2-tetrachloroethane was the least volatilized in the TF and bromoform was least volatilized in the RBC. Toulene, o-xylene and 1,3,5-trimethylbenzene were biodegraded to the greatest extent and 1,1,2,2-tetrachloroethane was least biodegraded. Increasing the hydraulic loading tended to increase the proportion of influent VOCs found in the TF effluent. Imposing effluent recycle on the TF increased the fraction of influent VOCs found in the effluent, but also decreased the fraction stripped and increased the fraction that was biodegraded. Increasing hydraulic loading to the RBC tended to increase the proportion of influent VOCs found in the effluent and off-gas. Increasing the RBC disc rotational speed increased the fraction that was biodegraded and decreased the fraction of VOCs found in the effluent and off-gas streams. The TF tended to have greater losses to volatilization than the RBC while the RBC maintained a greater fraction of the candidate VOCs in the process effluent than the TF. Differences between the processes with respect to biodegradation could not be inferred.

Parker, W.J. [Carleton Univ., Ottawa, Ontario (Canada). Dept. of Civil and Environmental Engineering; Monteith, H.D. [Enviromega Ltd., Hamilton, Ontario (Canada); Melcer, H. [Brown and Caldwell Consultants, Seattle, WA (United States)

1996-07-01

203

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

204

Photochemical pollution at two southern California smog receptor sites  

SciTech Connect

A one-year survey of air quality has been carried out at two southern California inland locations, Perris and Palm Springs to evaluate transport of photochemical smog from the Los Angeles area and to assess population exposure to toxic air pollutants in the Coachella Valley and eastern Riverside County. Air pollutants measured included formaldehyde, acetaldehyde, nitric acid, and peroxyacetyl nitrate (PAN). Acetic acid was also measured as part of the time-integrated method employed to measure PAN. In addition, intensive studies were carried out at both locations and included measurements of aldehydes, nitric acid, PAN, peroxypropionyl nitrate (PPN), methylchloroform and tetrachloroethylene. Maximum concentrations of HCHO, CH{sub 3}CHO, HNO{sub 3}, PAN, PPN, CH{sub 3}COOH and C{sub 2}Cl{sub 4} were 26, 21, 4.5, 7.6, 0.42, 6.6 and 0.29 ppb in Palm Springs and 15, 30, 6.3, 9.1, 0.73, 7.8 and 0.43 ppb in Perris. Pollutant concentrations measured in Palm Springs and Perris are compared to those measured in the Los Angeles area, and are discussed in terms of formation and removal during transport.

Grosjean, D.; Williams, E.L. II. (DGA, Inc., Ventura, CA (United States))

1992-06-01

205

Air purification from TCE and PCE contamination in a hybrid bioreactors and biofilter integrated system.  

PubMed

A two-stage waste air treatment system, consisting of hybrid bioreactors (modified bioscrubbers) and a biofilter, was used to treat waste air containing chlorinated ethenes - trichloroethylene (TCE) and tetrachloroethylene (PCE). The bioreactor was operated with loadings in the range 0.46-5.50gm(-3)h(-1) for TCE and 2.16-9.02gm(-3)h(-1) for PCE. The biofilter loadings were in the range 0.1-0.97gm(-3)h(-1) for TCE and 0.2-2.12gm(-3)h(-1) for PCE. Under low pollutant loadings, the efficiency of TCE elimination was 23-25% in the bioreactor and 54-70% in the biofilter. The efficiency of PCE elimination was 44-60% in the bioreactor and 50-75% in the biofilter. The best results for the bioreactor were observed one week after the pollutant loading was increased. However, the process did not stabilize. In the next seven days contaminant removal efficiency, enzymatic activity and biomass content were all diminished. PMID:24316808

Tabernacka, Agnieszka; Zborowska, Ewa; Lebkowska, Maria; Borawski, Maciej

2014-01-15

206

Chemical oxidation of volatile and semi-volatile organic compounds in soil  

SciTech Connect

Subsurface contamination with fuel hydrocarbons or chlorinated hydrocarbons is prevalent throughout the Department of Energy (DOE) complex and in many sites managed by the Environmental Protection Agency (EPA) Superfund program. The most commonly reported chlorinated hydrocarbons (occurring > 50% of DOE contaminated sites) were trichloroethylene (TCE), 1, 1, 1,-trichloroethane (TCA), and tetrachloroethylene (PCE) with concentrations in the range of 0.2 {mu}g/kg to 12,000 mg/kg. The fuel hydrocarbons most frequently reported as being present at DOE sites include aromatic compounds and polyaromatic compounds such as phenanthrene, pyrene, and naphthalene. The primary sources of these semi-volatile organic compounds (SVOCs) are coal waste from coal fired electric power plants used at many of these facilities in the past and gasoline spills and leaks. Dense non-aqueous phase liquids (DNAPLs) can migrate within the subsurface for long periods of time along a variety of pathways including fractures, macropores, and micropores. Diffusion of contaminants in the non-aqueous, aqueous, and vapor phase can occur from the fractures and macropores into the matrix of fine-textured media. As a result of these contamination processes, removal of contaminants from the subsurface and the delivery of treatment agents into and throughout contaminated regions are often hindered, making rapid and extensive remediation difficult.

Gates, D.D.; Siegrist, R.L.; Cline, S.R.

1995-06-01

207

Cometabolic degradation of chlorinated alkenes by alkene monooxygenase in a propylene-grown Xanthobacter strain.  

PubMed Central

Propylene-grown Xanthobacter cells (strain Py2) degraded several chlorinated alkenes of environmental concern, including trichloroethylene, 1-chloroethylene (vinyl chloride), cis- and trans-1,2-dichloroethylene, 1,3-dichloropropylene, and 2,3-dichloropropylene. 1,1-Dichloroethylene was not degraded efficiently, while tetrachloroethylene was not degraded. The role of alkene monooxygenase in catalyzing chlorinated alkene degradations was established by demonstrating that glucose-grown cells which lack alkene monooxygenase and propylene-grown cells in which alkene monooxygenase was selectively inactivated by propyne were unable to degrade the compounds. C2 and C3 chlorinated alkanes were not oxidized by alkene monooxygenase, but a number of these compounds were inhibitors of propylene and ethylene oxidation, suggesting that they compete for binding to the enzyme. A number of metabolites enhanced the rate of degradation of chlorinated alkenes, including propylene oxide, propionaldehyde, and glucose. Propylene stimulated chlorinated alkene oxidation slightly when present at a low concentration but became inhibitory at higher concentrations. Toxic effects associated with chlorinated alkene oxidations were determined by measuring the propylene oxidation and propylene oxide-dependent O2 uptake rates of cells previously incubated with chlorinated alkenes. Compounds which were substrates for alkene monooxygenase exhibited various levels of toxicity, with 1,1-dichloroethylene and trichloroethylene being the most potent inactivators of propylene oxidation and 1,3- and 2,3-dichloropropylene being the most potent inactivators of propylene oxide-dependent O2 uptake. No toxic effects were seen when cells were incubated with chlorinated alkenes anaerobically, indicating that the product(s) of chlorinated alkene oxidation mediates toxicity. PMID:1444418

Ensign, S A; Hyman, M R; Arp, D J

1992-01-01

208

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, J.J., Jr.; Lord, D.G.

1985-01-01

209

Effects of Daily Precipitation and Evapotranspiration Patterns on Flow and VOC Transport to Groundwater along a Watershed Flow Path  

USGS Publications Warehouse

MTBE and other volatile organic compounds (VOCs) are widely observed in shallow groundwater in the United States, especially in urban areas. Previous studies suggest that the atmosphere and/or nonpoint surficial sources could be responsible for some of those VOCs, especially in areas where there is net recharge to groundwater. However, in semiarid locations where annual potential evapotranspiration can exceed annual precipitation, VOC detections in groundwater can be frequent. VOC transport to groundwater under net discharge conditions has not previously been examined. A numerical model is used here to demonstrate that daily precipitation and evapotranspiration (ET) patterns can have a significant effect on recharge to groundwater, water table elevations, and VOC transport. Ten-year precipitation/ET scenarios from six sites in the United States are examined using both actual daily observed values and "average" pulsed precipitation. MTBE and tetrachloroethylene transport, including gas-phase diffusion, are considered. The effects of the precipitation/ET scenarios on net recharge and groundwater flow are significant and complicated, especially under low-precipitation conditions when pulsed precipitation can significantly underestimate transport to groundwater. In addition to precipitation and evapotranspiration effects, location of VOC entry into the subsurface within the watershed is important for transport in groundwater. This is caused by groundwater hydraulics at the watershed scale as well as variations in ET within the watershed. The model results indicate that it is important to consider both daily precipitation/ET patterns and location within the watershed in order to interpret VOC occurrence in groundwater, especially in low-precipitation settings.

Johnson, R.L.; Thoms, R.B.; Zogorski, J.S.

2003-01-01

210

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. PMID:21392400

2011-01-01

211

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

2008-09-01

212

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

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

213

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

214

Risk assessment of exposure to volatile organic compounds in groundwater in Taiwan.  

PubMed

The purpose of this study is to assess the risks from exposure to 14 volatile organic compounds (VOCs) in selected groundwater sites in Taiwan. The study employs the multimedia environment pollutant assessment system (MEPAS) model to calculate the specific non-cancer and cancer risks at an exposure level of 1 microg/L of each VOC for a variety of exposure pathways. The results show that the highest specific non-cancer risk is associated with water ingestion of vinyl chloride (VC) and that the highest specific cancer risk is associated with indoor breathing of VC. The three most important exposure pathways for risk assessment for both non-cancer and cancer risks are identified as water ingestion, dermal absorption when showering, and indoor breathing. Excess tetrachloroethylene (PCE), trichloroethylene (TCE), dichloroethylene (DCE), and VC are detected in the groundwater aquifers of one dump site and one factory. However, the study suggests that the pollutants in the contaminated groundwater aquifers do not travel extensively with groundwater flow and that the resulting VOC concentrations are below detectable levels for most of the sampled drinking-water treatment plants. Nevertheless, the non-cancer and cancer risks resulting from use of the contaminated groundwater are found to be hundred times higher than the general risk guidance values. To ensure safe groundwater utilisation, remediation initiatives for soil and groundwater are required. Finally, the study suggests that the current criteria for VOCs in drinking water might not be capable of ensuring public safety when groundwater is used as the primary water supply; more stringent quality criteria for drinking water are proposed for selected VOCs. PMID:19167026

Fan, Chihhao; Wang, Gen-Shuh; Chen, Yen-Chuan; Ko, Chun-Han

2009-03-15

215

Limited representation of drinking-water contaminants in pregnancy-birth cohorts.  

PubMed

Water contamination and noise have been consistently the least assessed environmental/lifestyle exposures in pregnancy-birth cohorts (PBC). Water quality surveillance data collected during the past decade within urban drinking-water distribution systems call for re-evaluation of water and health issues in the developed world. The objectives of this scientific commentary were to (i) highlight the extent of appraisal of water contamination in exposure assessment studies of PBC, worldwide, and (ii) propose recommendations to increase awareness of emerging water-related risks through their improved representation into PBC study designs in urban centers. Three scientific literature databases (Scopus, PubMed, and Web of Science) were used for a systematic search on worldwide PBC and their publications that considered water contamination and health outcomes. Publicly-available e-databases (ENRIECO, BIRTHCOHORTS, and CHICOS) were also employed for detailed exploration of existing European Union (EU)-based PBC. Out of the 76 PBC identified in the EU territory, only 12 of them incorporated water contamination into their study designs. Among which only 6 PBC published scientific articles that either included data on water contamination and/or water intake estimates. Trihalomethanes but not other disinfection by-products were mostly studied in the PBC around the globe, while fluoride, atrazine, perfluorinated compounds, tetrachloroethylene, and lead were studied to a lesser extent as water contaminants. It appears that chemical-based water contamination and corresponding human exposures represent a largely underappreciated niche of exposure science pertaining to pregnant mother and children's health in PBC. Future PBC studies should grasp this opportunity to substantially reform elements of water contamination in their exposure assessment protocols and effectively combine them with their epidemiological study designs. PMID:24013514

Makris, Konstantinos C; Andra, Syam S

2014-01-15

216

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

217

Aromatic hydrocarbons as ozone precursors before and after outbreak of the 2008 financial crisis in the Pearl River Delta region, south China  

NASA Astrophysics Data System (ADS)

In the second half of 2008 China's highly industrialized Pearl River Delta (PRD) region was hard-hit by the financial crisis (FC). This study reports volatile organic compounds measured in the PRD during November-December in both 2007 before the FC and 2008 after the FC. While total mixing ratios of non-methane hydrocarbons (NMHCs) on average were only about 7% lower from 40.2 ppbv in 2007 to 37.5 ppbv in 2008, their ozone formation potentials (OFPs) dropped about 30%, resulting from about 55% plummet of aromatic hydrocarbons (AHs) against a greater than 20% increase of total alkanes/alkenes. The elevated alkanes and alkenes in 2008 could be explained by greater emissions from vehicle exhausts and LPG combustion due to rapid increase of vehicle numbers and LPG consumption; the drop of AHs could be explained by reduced emissions from industries using AH-containing solvents due to the influence of the FC, as indicated by much lower ratios of toluene to benzene and of xylenes/trichloroethylene/tetrachloroethylene to carbon monoxide (CO) in 2008. Source apportionment by positive matrix factorization (PMF) also revealed much less contribution of industry solvents to total anthropogenic NMHCs and particularly to toluene and xylenes in 2008 than in 2007. Based on PMF reconstructed source contributions, calculated OFPs by industrial emissions were responsible for 40.8% in 2007 in contrast to 18.4% in 2008. Further investigation into local industry output statistics suggested that the plummet of AHs in 2008 should be attributed to small enterprises, which contributed largely to ambient AHs due to their huge numbers and non-existent emission treatment, but were much more influenced by the FC.

Zhang, Yanli; Wang, Xinming; Blake, Donald R.; Li, Longfeng; Zhang, Zhou; Wang, Shaoyi; Guo, Hai; Lee, Frank S. C.; Gao, Bo; Chan, Loyin; Wu, Dui; Rowland, F. Sherwood

2012-08-01

218

Field-scale prediction of enhanced DNAPL dissolution based on partitioning tracers  

NASA Astrophysics Data System (ADS)

The equilibrium streamtube model (EST) has demonstrated the ability to accurately predict dense nonaqueous phase liquid (DNAPL) dissolution in laboratory experiments and numerical simulations. Here the model is applied to predict DNAPL dissolution at a tetrachloroethylene (PCE)-contaminated dry cleaner site, located in Jacksonville, Florida. The EST model is an analytical solution with field-measurable input parameters. Measured data from a field-scale partitioning tracer test were used to parameterize the EST model and the predicted PCE dissolution was compared to measured data from an in-situ ethanol flood. In addition, a simulated partitioning tracer test from a calibrated, three-dimensional, spatially explicit multiphase flow model (UTCHEM) was also used to parameterize the EST analytical solution. The EST ethanol prediction based on both the field partitioning tracer test and the simulation closely matched the total recovery well field ethanol data with Nash-Sutcliffe efficiency E = 0.96 and 0.90, respectively. The EST PCE predictions showed a peak shift to earlier arrival times for models based on either field-measured or simulated partitioning tracer tests, resulting in poorer matches to the field PCE data in both cases. The peak shifts were concluded to be caused by well screen interval differences between the field tracer test and ethanol flood. Both the EST model and UTCHEM were also used to predict PCE aqueous dissolution under natural gradient conditions, which has a much less complex flow pattern than the forced-gradient double five spot used for the ethanol flood. The natural gradient EST predictions based on parameters determined from tracer tests conducted with a complex flow pattern underestimated the UTCHEM-simulated natural gradient total mass removal by 12% after 170 pore volumes of water flushing indicating that some mass was not detected by the tracers likely due to stagnation zones in the flow field. These findings highlight the important influence of well configuration and the associated flow patterns on dissolution.

Wang, Fang; Annable, Michael D.; Jawitz, James W.

2013-09-01

219

Field-scale prediction of enhanced DNAPL dissolution based on partitioning tracers.  

PubMed

The equilibrium streamtube model (EST) has demonstrated the ability to accurately predict dense nonaqueous phase liquid (DNAPL) dissolution in laboratory experiments and numerical simulations. Here the model is applied to predict DNAPL dissolution at a tetrachloroethylene (PCE)-contaminated dry cleaner site, located in Jacksonville, Florida. The EST model is an analytical solution with field-measurable input parameters. Measured data from a field-scale partitioning tracer test were used to parameterize the EST model and the predicted PCE dissolution was compared to measured data from an in-situ ethanol flood. In addition, a simulated partitioning tracer test from a calibrated, three-dimensional, spatially explicit multiphase flow model (UTCHEM) was also used to parameterize the EST analytical solution. The EST ethanol prediction based on both the field partitioning tracer test and the simulation closely matched the total recovery well field ethanol data with Nash-Sutcliffe efficiency E=0.96 and 0.90, respectively. The EST PCE predictions showed a peak shift to earlier arrival times for models based on either field-measured or simulated partitioning tracer tests, resulting in poorer matches to the field PCE data in both cases. The peak shifts were concluded to be caused by well screen interval differences between the field tracer test and ethanol flood. Both the EST model and UTCHEM were also used to predict PCE aqueous dissolution under natural gradient conditions, which has a much less complex flow pattern than the forced-gradient double five spot used for the ethanol flood. The natural gradient EST predictions based on parameters determined from tracer tests conducted with a complex flow pattern underestimated the UTCHEM-simulated natural gradient total mass removal by 12% after 170 pore volumes of water flushing indicating that some mass was not detected by the tracers likely due to stagnation zones in the flow field. These findings highlight the important influence of well configuration and the associated flow patterns on dissolution. PMID:23911784

Wang, Fang; Annable, Michael D; Jawitz, James W

2013-09-01

220

Occupational cancer burden in Great Britain.  

PubMed

A sound knowledge base is required to target resources to reduce workplace exposure to carcinogens. This project aimed to provide an objective estimate of the burden of cancer in Britain due to occupation. This volume presents extensive analyses for all carcinogens and occupational circumstances defined as definite or probable human occupational carcinogens by the International Agency for Research on Cancer. This article outlines the structure of the supplement - two methodological papers (statistical approach and exposure assessment), eight papers presenting the cancer-specific results grouped by broad anatomical site, a paper giving industry sector results and one discussing work-related cancer-prevention strategies. A brief summary of the methods and an overview of the updated overall results are given in this introductory paper. A general discussion of the overall strengths and limitations of the study is also presented. Overall, 8010 (5.3%) total cancer deaths in Britain and 13,598 cancer registrations were attributable to occupation in 2005 and 2004, respectively. The importance of cancer sites such as mesothelioma, sinonasal, lung, nasopharynx, breast, non-melanoma skin cancer, bladder, oesophagus, soft tissue sarcoma and stomach cancers are highlighted, as are carcinogens such as asbestos, mineral oils, solar radiation, silica, diesel engine exhaust, coal tars and pitches, dioxins, environmental tobacco smoke, radon, tetrachloroethylene, arsenic and strong inorganic mists, as well as occupational circumstances such as shift work and occupation as a painter or welder. The methods developed for this project are being adapted by other countries and extended to include social and economic impact evaluation. PMID:22710676

Rushton, Lesley; Hutchings, Sally J; Fortunato, Lea; Young, Charlotte; Evans, Gareth S; Brown, Terry; Bevan, Ruth; Slack, Rebecca; Holmes, Phillip; Bagga, Sanjeev; Cherrie, John W; Van Tongeren, Martie

2012-06-19

221

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

222

Reconnaissance of volatile organic compounds in the subsurface at Rutgers University, Busch Campus, Piscataway Township, New Jersey  

USGS Publications Warehouse

During 1991-92, the U.S. Geological Survey conducted a hydrogeologic reconnaissance at a site near the Rutgers University, Busch Campus, Chemical Engineering building, C-Wing. Results of analyses of the soil-gas samples, which were collected at 43 locations, indicated the presence of volatile organic compounds, primarily carbon tetrachloride, near the C-Wing building and about 550 feet downgradient from and southwest of the C-Wing building. Concentrations of the compound in soil-gas samples were highest (2.1 ug/L (micrograms per liter)) along the southwestern wall of the C-Wing building. Ground-water samples were collected at depths as great as 55 feet from five wells and piezometers near the C-Wing building. Samples collected along the southwestern wall of the building also contained the highest concentrations of volatile organic compounds. Concentrations of carbon tetrachloride in the ground-water samples ranged from < 0.35 ug/L to 3,400 ug/L, and concentrations of tetrachloro- ethylene ranged from < 0.28 ug/L to 85 ug/L. Ground-water samples collected at depths of 55 feet or more from two wells located on the Rutgers University Golf Course about 2,400 feet down- gradient from the C-Wing building contained concentrations of tetrachloroethylene as great as 17.7 ug/L. Water levels measured in six wells and six piezometers indicated that the general flow direction in the shallow part of the aquifer is to the southwest of the C-Wing building. An electrical-resistivity survey was conducted by azimuthal resistivity techniques. The results of the survey were consistent with field measurements, and the dominant vertical fractures near the Busch Campus trend northeast. An electromagnetic survey was ineffective as a result of cultural interferences and could not be used to determine the hydrogeologic characteristics of the site.

dePaul, V. T.

1996-01-01

223

Valiant 'Zero-Valent' Effort Restores Contaminated Grounds  

NASA Technical Reports Server (NTRS)

Dense non-aqueous phase liquids (DNAPLs) are chemical compounds that can contaminate soil and groundwater to the point of irreparability. These substances are only slightly soluble in water, and are much denser than water. Because of their solubility, DNAPLs form separate liquid phases in groundwater, and because of their density, DNAPLs sink in aquifers instead of floating at the water table, making it extremely difficult to detect their presence. If left untreated in the ground, they can taint fresh water sources. Common DNAPLs include chlorinated hydrocarbon compounds such as carbon tetrachloride, chloroform, tetrachloroethylene, and trichloroethylene. Trichloroethylene was used during the early days of the Space Program, as a solvent for flushing rocket engines, and for metal cleaning and degreasing of equipment, electronics, and heavy machinery. As a result, areas of Cape Canaveral s Launch Complex 34, the site of several historic Saturn rocket launches occurring from 1959 to 1968, were polluted with chlorinated DNAPLs. Through the direction and guidance of Dr. Jacqueline Quinn, an environmental engineer in the Spaceport Engineering and Technology Directorate at NASA s Kennedy Space Center, a biodegradable environmental cleanup technology was developed to reductively dechlorinate DNAPL sources in polluted water at Launch Complex 34. It was important for Kennedy to nip this problem in the bud, in light of the fact that the Space Center is also a National Wildlife Refuge, home to thousands of shorebirds, endangered sea turtles and eagles, manatees, alligators, and diverse habitats that include brackish marshes and salt water estuaries. The success in remediating this historic launch site has led to numerous commercial applications that are restoring the health of our environmental surroundings.

2005-01-01

224

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

PubMed Central

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

2014-01-01

225

Partitioning of non-ionic surfactants between water and non-aqueous phase liquids (NAPLs) of chlorinated organics  

NASA Astrophysics Data System (ADS)

Due to the hydrophobic nature, chlorinated organic compounds penetrate soil and groundwater to form non-aqueous phase liquids (NAPLs). At the sites contaminated with such NAPLs, thus, surfactants are applied to increase the aqueous solubility of chlorinated organics via micellar solubilization. However, a portion of surfactants can be partitioned into NAPL phases by forming reverse micelles within them. Consequently, lesser amounts of surfactants are available for the micellar solubilization of chlorinated organics in the aqueous phase. In this study, we investigated the partitioning behavior of non-ionic surfactants (Tween 20, Tween 40, Tween 80, and Triton X-100) between water and a NAPL phase consisting of tetrachloroethylene (PCE), trichloroethylene (TCE), or chloroform (CF). According to the experimental results, the partitioning of surfactants in the water-NAPL systems was found to follow linear or Langmuir-type isotherms. Regardless of type of surfactants, the partitioning loss of surfactants into NAPLs became greater with the more hydrophilic (i.e., the lower water-NAPL interfacial tension) chlorinated organics: PCE < TCE < CF. Notably, the partitioning of all Tween surfactants into the NAPLs consisting of the least hydrophilic PCE was minimal. The partitioning behavior among different surfactants was somewhat complicated. The partitioning extent into CF-NAPLs increased in the order of Tween 20 < Tween 40 < Tween 80 << Triton X-100, suggesting that the greater partitioning occurred with the more hydrophobic (i.e., the lower hydrophilic-lipophilic balance, HLB) surfactant. Consistent with this postulation, the surfactant partitioning into PCE-NAPLs showed the similar trend. In case of TCE-NAPLs, however, the more hydrophobic Tween 40 was partitioned to a less extent than Tween 20. Therefore, the specific interaction of a NAPL-surfactant pair as well as their individual properties should be considered when selecting an effective surfactant for the remediation of a NAPL-contaminated site.

KANG, S.; Jeong, H. Y.

2013-12-01

226

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. PMID:12573900

Aschengrau, Ann; Rogers, Sarah; Ozonoff, David

2003-01-01

227

Adhesion of biodegradative anaerobic bacteria to solid surfaces  

SciTech Connect

In order to exploit the ability of anaerobic bacteria to degrade certain contaminants for bioremediation of polluted subsurface environments, the authors need to understand the mechanisms by which such bacteria partition between aqueous and solid phases, as well as the environmental conditions that influence partitioning. They studied four strictly anaerobic bacteria, Desulfomonile tiedjei, Syntrophomonas wolfei, Syntrophobacter wolinii, and Desulfovibrio sp. strain G11, which theoretically together can constitute a tetrachloroethylene- and trichloroethylene-dechlorinating consortium. Adhesion of these organisms was evaluated by microscopic determination of the numbers of cells that attached to glass coverslips exposed to cell suspensions under anaerobic conditions. The authors studied the effects of the growth phase of the organisms on adhesion, as well as the influence of electrostatic and hydrophobic properties of the substratum. Results indicate that S. wolfei adheres in considerably higher numbers to glass surfaces than the other three organisms. Starvation greatly decreases adhesion of S. wolfei and Desulfovibrio sp. strain G11 but seems to have less of an effect on the adhesion of the other bacteria. The presence of Fe{sup 3+} on the substratum, which would be electropositive, significantly increased the adhesion of S. wolfei, whereas the presence of silicon hydrophobic groups decreased the numbers of attached cells of all species. Measurements of transport of cells through hydrophobic-interaction and electro-static-interaction columns indicated that all four species had negatively charged cell surfaces and that D. tiedjei and Desulfovibrio sp. strain G11 possessed some hydrophobic cell surface properties. These findings are an early step toward understanding the dynamic attachment of anaerobic bacteria in anoxic environments.

Schie, P.M. van; Fletcher, M.

1999-11-01

228

[Solute transport modeling application in groundwater organic contaminant source identification].  

PubMed

Investigation and numerical simulation, based on RT3D (reactive transport in 3-dimensions)were used to identify the source of tetrachloroethylene (PCE) and trichloroethylene (TCE) in the groundwater of a city in the north of China and reverse the input intensity. Multiple regressions were applied to analyze the influenced factors of input intensity of PCE and TCE using Stepwise function in Matlab. The results indicate that the factories and industries are the source of the PCE and TCE in groundwater. Natural attenuation was identified and the natural attenuation rates are 93.15%, 61.70% and 61.00% for PCE, and 70.05%, 73.66% and 63.66% for TCE in 173 days. The 4 source points identified by the simulation have released 0.910 6 kg PCE and 95.693 8 kg TCE during the simulation period. The regression analysis results indicate that local precipitation and the thickness of vadose zone are the main factors influencing organic solution transporting from surface to groundwater. The PCE and TCE concentration are found to be 0 and 5 mg x kg(-1) from surface to 35 cm in vadose zone. All above results suggest that PCE and TCE in groundwater are from the source in the surface. Natural attenuation occurred when PCE and TCE transporting from the surface to groundwater, and the rest was transported to groundwater through vadose zone. Local precipitation was one of the critical factors influencing the transportation of PCE and TCE to aquifer through sand, pebble and gravel of the Quaternary. PMID:22624366

Wang, Shu-Fang; Wang, Li-Ya; Wang, Xiao-Hong; Lin, Pei; Liu, Jiu-Rong; Xin, Bao-Dong; He, Guo-Ping

2012-03-01

229

Occupation and cancer in Britain  

PubMed Central

Background: Prioritising control measures for occupationally related cancers should be evidence based. We estimated the current burden of cancer in Britain attributable to past occupational exposures for International Agency for Research on Cancer (IARC) group 1 (established) and 2A (probable) carcinogens. Methods: We calculated attributable fractions and numbers for cancer mortality and incidence using risk estimates from the literature and national data sources to estimate proportions exposed. Results: 5.3% (8019) cancer deaths were attributable to occupation in 2005 (men, 8.2% (6362); women, 2.3% (1657)). Attributable incidence estimates are 13?679 (4.0%) cancer registrations (men, 10?063 (5.7%); women, 3616 (2.2%)). Occupational attributable fractions are over 2% for mesothelioma, sinonasal, lung, nasopharynx, breast, non-melanoma skin cancer, bladder, oesophagus, soft tissue sarcoma, larynx and stomach cancers. Asbestos, shift work, mineral oils, solar radiation, silica, diesel engine exhaust, coal tars and pitches, occupation as a painter or welder, dioxins, environmental tobacco smoke, radon, tetrachloroethylene, arsenic and strong inorganic mists each contribute 100 or more registrations. Industries and occupations with high cancer registrations include construction, metal working, personal and household services, mining, land transport, printing/publishing, retail/hotels/restaurants, public administration/defence, farming and several manufacturing sectors. 56% of cancer registrations in men are attributable to work in the construction industry (mainly mesotheliomas, lung, stomach, bladder and non-melanoma skin cancers) and 54% of cancer registrations in women are attributable to shift work (breast cancer). Conclusion: This project is the first to quantify in detail the burden of cancer and mortality due to occupation specifically for Britain. It highlights the impact of occupational exposures, together with the occupational circumstances and industrial areas where exposures to carcinogenic agents occurred in the past, on population cancer morbidity and mortality; this can be compared with the impact of other causes of cancer. Risk reduction strategies should focus on those workplaces where such exposures are still occurring. PMID:20424618

Rushton, L; Bagga, S; Bevan, R; Brown, T P; Cherrie, J W; Holmes, P; Fortunato, L; Slack, R; Van Tongeren, M; Young, C; Hutchings, S J

2010-01-01

230

Characterization Report to Support the Phytoremediation Efforts for Southern Sector, Savannah River Site, Aiken, South Carolina  

SciTech Connect

In February, 1999, we conducted a small-scale characterization effort to support future remediation decisions for the Southern Sector of the upper Three Runs watershed. The study concentrated on groundwater adjacent to the seepline at Tim's Branch above and below Steed's Pond. the primary compounds of interest were the volatile organic contaminants (VOCs), trichlorethylene (TCE) and tetrachloroethylene (PCE). Due to the site topography and hydrogeology, samples collected north of Steed's Pond were from the M-Area (water table) aquifer; while those locations south of Steed's Pond provided samples from the Lost Lake aquifer. Results of the study suggest that the leading edge of the A/M Area plume in the Lost Lake aquifer may be approaching the seepline at Tim's Branch below Steed's Pond, south of Road 2. Neither TCE nor PCE were detected int he samples targeting the seepline of the water table aquifer. The concentrations found for both TCE and PCE associated with the Lost Lake aquifer outcrop region were slightly above the detection limit of the analytical instrument used. The findings of this study are consistent with the conceptual model for the organic contaminant plume in the A/M Area of the Savannah River Site (SRS) -- the plume in the Southern Sector is known to be depth discrete and primarily in the Lost lake Aquifer. The sites with detected VOCs are in the most upstream accessible reaches of Tim's Branch where water from the Lost Lake Aquifer crops out. Additional characterization efforts should be directed near this region to confirm the results and to support future planning for the dilute-distal portions of the A/M Area plume. These data, combined with existing groundwater plume data and future characterization results will provide key information to estimate potential contaminant flux to the seepline and to assess the effectiveness of potential clean-up activities such as phytoremediation.

Jerome, K.M.

1999-06-08

231

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

232

Characterization of anaerobic chloroethene-dehalogenating activity in several subsurface sediments  

SciTech Connect

Anaerobic microcosms of subsurface soils from four locations were used to investigate the separate effects of several electron donors on tetrachloroethylene (PCE) dechlorination activity. The substrates tested were methanol, formate, lactate, acetate, and sucrose. Various levels of sulfate-reducing, acetogenic, fermentative, and methanogenic activity were observed in all sediments. PCE dechlorination was detected in all microcosms, but the amount of dehalogenation varied by several orders of magnitude. Trichloroethylene was the primary dehalogenation product; however, small amounts of cis-1,2-dichloroethylene, 1,1-dichloroethylene, and vinyl chloride were also detected in several microcosms. Lactate-amended microcosms showed large amounts of dehalogenation. in three of the four sediments. One of the two sediments which showed positive activity with lactate also had large amounts of delialogenation with methanol. Sucrose, formate, and acetate also stimulated large amounts of delialogenation in one sediment that showed activity with lactate. These results suggest that lactate may be an appropriate substrate for screening sediments for PCE or TCE delialogenation activity, but that the microbial response is not sufficient for complete in situ bioremediation. A detailed study of the Victoria activity revealed that delialogenation rates were more similar to the Cornell culture than to rates measured for methanogens, or a methanol-enriched sediment culture. This may suggest that these sediments contain a highly efficient delialogenation activity similar to the Cornell culture. This assertion is supported further by the fact that an average of 3% of added reducing equivalents could be diverted to dehalogenation in tests which were conducted using PCE-saturated hexadecane as a constant source of PCE during incubation. Further evidence is needed to confirm this premise. The application of these results to in situ bioremediation of highly contaminated areas are discussed.

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

1996-11-01

233

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

234

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

PubMed

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

Parshetti, Ganesh K; Doong, Ruey-an

2012-01-01

235

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

236

Assessment of soil-gas contamination at three former fuel-dispensing sites, Fort Gordon, Georgia, 2010—2011  

USGS Publications Warehouse

Soil gas was assessed for contaminants at three former fuel-dispensing sites at Fort Gordon, Georgia, from October 2010 to September 2011. The assessment included delineation of organic contaminants using soil-gas samplers collected from the former fuel-dispensing sites at 8th Street, Chamberlain Avenue, and 12th Street. This assessment was conducted to provide environmental contamination data to Fort Gordon personnel pursuant to requirements for the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Soil-gas samplers installed and retrieved during June and August 2011 at the 8th Street site had detections above the method detection level (MDL) for the mass of total petroleum hydrocarbons (TPH), benzene, toluene, ortho-xylene, undecane, tridecane, pentadecane, and chloroform. Total petroleum hydrocarbons soil-gas mass exceeded the MDL of 0.02 microgram in 54 of the 55 soil-gas samplers. The highest detection of TPH soil-gas mass was 146.10 micrograms, located in the central part of the site. Benzene mass exceeded the MDL of 0.01 microgram in 23 soil-gas samplers, whereas toluene was detected in only 10 soil-gas samplers. Ortho-xylene was detected above the MDL in only one soil-gas sampler. The highest soil-gas mass detected for undecane, tridecane, and pentadecane was located in the northeastern corner of the 8th Street site. Chloroform mass greater than the MDL of 0.01 microgram was detected in less than one-third of the soil-gas samplers. Soil-gas masses above the MDL were identified for TPH, gasoline-related compounds, diesel-range alkanes, trimethylbenzenes, naphthalene, 2-methyl-napthalene, octane, and tetrachloroethylene for the July 2011 soil-gas survey at the Chamberlain Avenue site. All 30 of the soil-gas samplers contained TPH mass above the MDL. The highest detection of TPH mass, 426.36 micrograms, was for a soil-gas sampler located near the northern boundary of the site. Gasoline-related compounds and diesel-range alkanes were detected in multiple soil-gas samplers, and the highest detections of these compounds were located near the central part of the site near existing, nonoperational, fuel-dispensing pumps. Trimethylbenzenes were detected in less than half of the soil-gas samplers. Naphthalene soil-gas mass was detected above the MDL in 10 soil-gas samplers, whereas 2-methyl-napthalene was detected above the MDL in half of the soil-gas samplers. Octane mass was detected above the MDL in one soil-gas sampler located near the central part of the site. Tetrachloroethylene soil-gas mass was detected above the MDL in more than half of the soil-gas samplers, and the highest tetrachloroethylene soil-gas mass of 0.90 microgram was located in the northeastern part of the site. Soil-gas samplers collected at the 12th Street site during July 2011 contained soil-gas mass above the MDL for TPH, toluene, undecane, tridecane, and pentadecane (diesel-range alkanes), trichloroethylene, 1,4-dichlorobenzene, chloroform, and 1,2,4-trimethylbenzene. The highest detected TPH mass was 24.37 micrograms in a soil-gas sampler located in the northern part of the site. The highest detection of toluene soil-gas mass was from a soil-gas sampler located near the southern boundary of the site. The diesel-range alkanes were detected above the MDL in five soil-gas samplers; the highest detection of soil-gas diesel mass, 0.65 microgram, was located in the southern part of the site. Trichloroethylene and 1,4-dichlorobenzene were detected above the MDL in the northern part of the site in one soil-gas sampler that also had one of the highest detections of TPH. Chloroform was detected above the MDL in three soil-gas samplers, whereas 1,2,4-trimethylbenzene soil-gas mass was detected above the MDL in two soil-gas samplers.

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

2012-01-01

237

Design and Operation of a Borehole Straddle Packer for Ground-Water Sampling and Hydraulic Testing of Discrete Intervals at U.S. Air Force Plant 6, Marietta, Georgia  

USGS Publications Warehouse

A borehole straddle packer was developed and tested by the U.S. Geological Survey to characterize the vertical distribution of contaminants, head, and hydraulic properties in open-borehole wells as part of an ongoing investigation of ground-water contamination at U.S. Air Force Plant 6 (AFP6) in Marietta, Georgia. To better understand contaminant fate and transport in a crystalline bedrock setting and to support remedial activities at AFP6, numerous wells have been constructed that include long open-hole intervals in the crystalline bedrock. These wells can include several discontinuities that produce water, which may contain contaminants. Because of the complexity of ground-water flow and contaminant movement in the crystalline bedrock, it is important to characterize the hydraulic and water-quality characteristics of discrete intervals in these wells. The straddle packer facilitates ground-water sampling and hydraulic testing of discrete intervals, and delivery of fluids including tracer suites and remedial agents into these discontinuities. The straddle packer consists of two inflatable packers, a dual-pump system, a pressure-sensing system, and an aqueous injection system. Tests were conducted to assess the accuracy of the pressure-sensing systems, and water samples were collected for analysis of volatile organic compound (VOCs) concentrations. Pressure-transducer readings matched computed water-column height, with a coefficient of determination of greater than 0.99. The straddle packer incorporates both an air-driven piston pump and a variable-frequency, electronic, submersible pump. Only slight differences were observed between VOC concentrations in samples collected using the two different types of sampling pumps during two sampling events in July and August 2005. A test conducted to assess the effect of stagnation on VOC concentrations in water trapped in the system's pump-tubing reel showed that concentrations were not affected. A comparison was conducted to assess differences between three water-sampling methods - collecting samples from the well by pumping a packer-isolated zone using a submersible pump, by using a grab sampler, and by using a passive diffusion sampler. Concentrations of tetrachloroethylene, trichloroethylene and 1,2-dichloropropane were greatest for samples collected using the submersible pump in the packed-isolated interval, suggesting that the straddle packer yielded the least dilute sample.

Holloway, Owen G.; Waddell, Jonathan P.

2008-01-01

238

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

239

Sorption of chlorinated solvents and degradation products on natural clayey tills.  

PubMed

The sorption of chlorinated solvents and degradation products on seven natural clayey till samples from three contaminated sites was investigated by laboratory batch experiments in order to obtain reliable sorption coefficients (K(d) values). The sorption isotherms for all compounds were nearly linear, but fitted by Freundlich isotherms slightly better over the entire concentration range. For chloroethylenes, tetrachloroethylene (PCE) was most strongly sorbed to the clayey till samples (K(d)=0.84-2.45Lkg(-1)), followed by trichloroethylene (TCE, K(d)=0.62-0.96Lkg(-1)), cis-dichloroethylene (cis-DCE, K(d)=0.17-0.82Lkg(-1)) and vinyl chloride (VC, K(d)=0.12-0.36Lkg(-1)). For chloroethanes, 1,1,1-trichloroethane (1,1,1-TCA) was most strongly sorbed (K(d)=0.2-0.45Lkg(-1)), followed by 1,1-dichloroethane (1,1-DCA, K(d)=0.16-0.24Lkg(-1)) and chloroethane (CA, K(d)=0.12-0.18Lkg(-1)). This is consistent with the order of hydrophobicity of the compounds. The octanol-water coefficient (logK(ow)) correlated slightly better with logK(d) values than logK(oc) values indicating that the K(d) values may be independent of the actual organic carbon content (f(oc)). The estimated logK(oc) or logK(d) for chlorinated solvents and degradation products determined by regression of data in this study were significantly higher than values determined by previously published empirical relationships. The site specific K(d) values as well as the new empirical relationship compared well with calculations on water and soil core concentration for cis-DCE and VC from the Rugårdsvej site. In conclusion, this study with a wide range of chlorinated ethenes and ethanes--in line with previous studies on PCE and TCE--suggest that sorption in clayey tills could be higher than typically expected. PMID:21459403

Lu, Cong; Bjerg, Poul L; Zhang, Fengjun; Broholm, Mette M

2011-06-01

240

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

2011-04-01

241

DUS II SOIL GAS SAMPLING AND AIR INJECTION TEST RESULTS  

SciTech Connect

Soil vapor extraction (SVE) and air injection well testing was performed at the Dynamic Underground Stripping (DUS) site located near the M-Area Settling Basin (referred to as DUS II in this report). The objective of this testing was to determine the effectiveness of continued operation of these systems. Steam injection ended on September 19, 2009 and since this time the extraction operations have utilized residual heat that is present in the subsurface. The well testing campaign began on June 5, 2012 and was completed on June 25, 2012. Thirty-two (32) SVE wells were purged for 24 hours or longer using the active soil vapor extraction (ASVE) system at the DUS II site. During each test five or more soil gas samples were collected from each well and analyzed for target volatile organic compounds (VOCs). The DUS II site is divided into four parcels (see Figure 1) and soil gas sample results show the majority of residual VOC contamination remains in Parcel 1 with lesser amounts in the other three parcels. Several VOCs, including tetrachloroethylene (PCE) and trichloroethylene (TCE), were detected. PCE was the major VOC with lesser amounts of TCE. Most soil gas concentrations of PCE ranged from 0 to 60 ppmv with one well (VEW-22A) as high as 200 ppmv. Air sparging (AS) generally involves the injection of air into the aquifer through either vertical or horizontal wells. AS is coupled with SVE systems when contaminant recovery is necessary. While traditional air sparging (AS) is not a primary component of the DUS process, following the cessation of steam injection, eight (8) of the sixty-three (63) steam injection wells were used to inject air. These wells were previously used for hydrous pyrolysis oxidation (HPO) as part of the DUS process. Air sparging is different from the HPO operations in that the air was injected at a higher rate (20 to 50 scfm) versus HPO (1 to 2 scfm). . At the DUS II site the air injection wells were tested to determine if air sparging affected VOC soil gas concentrations during ASVE. Five (5) SVE wells that were located closest to the air injection wells were used as monitoring points during the air sparging tests. The air sparging tests lasted 48 hours. Soil gas sample results indicate that sparging did not affect VOC concentrations in four of the five sparging wells, while results from one test did show an increase in soil gas concentrations.

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

2012-09-20

242

Cracking of Clay Due to Contact with Waste Chlorinated Solvents  

NASA Astrophysics Data System (ADS)

Clays are known to crack upon desiccation. Desiccation cracks of up to 3 cm wide have been reported in natural soils. This raises the question if a similar behavior is seen when a dense non-aqueous phase liquids (DNAPL) waste is in contact with clay. The contact with organic liquids causes the clay structure to shrink, leading to the formation of cracks. Moreover, DNAPL waste not only contains the organic liquid solvent but also includes surface-active solutes or surfactants. Such solutes can enhance the interaction of the organic solvents with the clay. This research will assess whether or not contact with chlorinated organic waste causes cracking. In order to evaluate the possibility of cracking in the clay, microcosms have been constructed that mimic aquifer systems, consisting of a saturated layer of sand, a saturated layer of bentonite clay and a 2.5 cm layer of either pure chlorinated solvents or DNAPL waste. The onset of cracking for the microcosm with tetrachloroethylene (PCE) waste as the DNAPL layer occurred after ten days of contact. Similarly, at eight days, cracks were observed in a microcosm containing trichloroethylene (TCE) waste . Forty-four days later, the length and number of cracks have grown considerably; with a total crack length of 50 cm on a surface of 80 cm2 in the microcosm containing PCE waste. On the other hand it took approximately 161 days for the clay layer in the microcosm containing pure PCE to crack. To quantity the degree of cracking, crack maps were developed using the image software, Image J. Characteristics like crack length, crack aperture, and the percentage of total length for a range of apertures were calculated using this software. For example, for the PCE waste microcosm, it was calculated that 3.7% of the crack length had an aperture of 100-300 microns, 15.1% of the crack length had an aperture of 300-500 microns, 29.7% of the crack length had an aperture of 500-700 microns, 40.1% of the crack length had an aperture of 700-900 microns, 6.3% had an aperture of 900-1,100 microns and 5.1% had an aperture of over 1,100 microns. These data suggest that aquitards in the field might crack when in contact with the DNAPL waste. Moreover, it is apparent that the waste contains solutes that accelerate the cracking of the clay layer. Thus, models examining the impact of storage in low permeability layers need to consider the possible impact of cracking.

Otero, M.; Ayral, D.; Shipan, J.; Goltz, M. N.; Huang, J.; Demond, A. H.

2012-12-01

243

Underestimated public health risks caused by overestimated VOC removal in wastewater treatment processes.  

PubMed

The uncontrolled release of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs) and the adverse health effects on the public have been of increasing concern. In this study, a lab-scale bioreactor was prepared to analyze the mass distribution of three aromatic (benzene, toluene, and xylenes) and four chlorinated VOCs (chloroform, carbon tetrachloride, trichloroethylene, and tetrachloroethylene) among the air, water and sludge phases in wastewater treatment processes. The VOC distribution through a full-scale WWTP in northern China was further investigated with respect to the effects of seasonal temperature variations and treatment technologies, followed by the cancer risk assessment using a steady-state Gaussian plume model (Industrial Source Complex) to simulate the atmospheric behaviors of the VOCs emitted from the WWTP. It was found that three aromatic hydrocarbons, notably benzene, were more readily released from the wastewater into the atmosphere, whereas the chlorinated compounds except chloroform were mainly present in the water phase through the treatment processes. The primary clarifier was the technology releasing high levels of VOCs into the atmosphere from the wastewater. The extents of volatilization or biodegradation, two important mechanisms to remove VOCs from wastewater, appeared to be determined by the physicochemical characteristics of the compounds, as the influence of treatment technologies (e.g., aeration) and seasonal temperature variations was rather limited. More importantly, the people living in the areas even more than 4 km away from the WWTP were still potentially exposed to cancer risks exceeding the regulatory threshold limit. The findings described the complex nature of VOC emissions from WWTPs and quantitatively indicated that the associated health impacts on the public near the WWTPs could be severely underestimated, whereas their treatment efficiencies by wastewater treatment technologies were overestimated. Instead of fully controlling the VOC release from WWTPs, the identification and abatement of important VOC species with regard to the atmospheric emission and health concerns is one possible alternative approach to effectively minimize the environmental and public health impacts by VOCs released from this particular source. PMID:24337048

Yang, Junchen; Wang, Kun; Zhao, Qingliang; Huang, Likun; Yuan, Chung-Shin; Chen, Wei-Hsiang; Yang, Wen-Bin

2014-02-01

244

Sub-ppb, Autonomous, Real-time Detection of VOCs with iCRDS  

NASA Astrophysics Data System (ADS)

The continuous, real-time detection of sub-parts-per-billion (ppb) concentrations of volatile organic compounds (VOCs) such as trichloroethylene (TCE) and tetrachloroethylene (PCE) remains difficult, time consuming and expensive. In particular, short term exposure spikes and diurnal variations are difficult or impossible to detect with traditional TO-15 measurements. We present laboratory and field performance data from an instrument based on incoherent cavity ringdown spectroscopy (iCRDS) that operates in the mid-infrared (bands from 860-1060 cm-1 or 970-1280 cm-1) and is capable of detecting a broad range of VOCs, in situ, continuously and autonomously. We have demonstrated the measurement of TCE in zero air with a precision of 0.17 ppb (1? in 4 minutes). PCE was measured with a precision of 0.15 ppb (1? in 4 minutes). Both of these measured precisions exceed the EPA's commercial building action limit, which for TCE is 0.92 ppb (5 ?g/m3) and for PCE is 0.29 ppb (2 ?g/m3). Additionally, the instrument is capable of precisely measuring and quantifying BTEX compounds (benzene, toluene, ethylbenzene, xylene), including differentiation of xylene isomers. We have demonstrated the accurate, interference free measurement of Mountain View, California air doped with TCE concentrations ranging from 4.22 ppb (22.8 ?g/m3) to 17.74 ppb (96 ?g/m3) with a precision of 1.42 ppb (1? in 4 minutes). Mountain View, California air doped with 10.83 ppb of PCE (74.0 ?g/m3) was measured with a precision of 0.54 ppb (1? in 4 minutes). Finally, the instrument was deployed to the Superfund site at Moffett Naval Air Station in Mountain View, California where contaminated ground water results in vapor intrusion of TCE and PCE. For two weeks, the instrument operated continuously and autonomously, successfully measuring TCE and PCE concentrations in both the breathing zone and steam tunnel air. TCE concentrations in the breathing zone averaged 0.186 × 0.669 ppb while tunnel air averaged 17.38 × 4.96 ppb, in excellent agreement with previous TO-15 8 hr averages. PCE concentrations in the breathing zone averaged 0.063 × 0.270 ppb while tunnel air averaged 0.755 × 0.359 ppb, again, in excellent agreement with previous TO-15 8 hr averages. The iCRDS instrument has shown the ability to continuously and autonomously measure sub-ppb levels of toxic VOCs in the field, offering an unprecedented picture of the short term dynamics associated with vapor intrusion and ground water pollution.

Leen, J.; Gupta, M.; Baer, D. S.

2013-12-01

245

Long-term ground penetrating radar monitoring of a small volume DNAPL release in a natural groundwater flow field.  

PubMed

An earlier field experiment at Canadian Forces Base Borden by Brewster and Annan [Geophysics 59 (1994) 1211] clearly demonstrated the capability of ground penetrating radar (GPR) reflection profiling to detect and monitor the formation of DNAPL layers in the subsurface. Their experiment involved a large volume release (770 L) of tetrachloroethylene into a portion of the sand aquifer that was hydraulically isolated from groundwater flow by sheet pile walls. In this study, we evaluated the ability of GPR profiling to detect and monitor much smaller volume releases (50 L). No subsurface confining structure was used in this experiment; hence, the DNAPL impacted zone was subjected to the natural groundwater flow regime. This condition allowed us to geophysically monitor the DNAPL mass loss over a 66 month period. Reflectivity variations on the GPR profiles were used to infer the presence and evolution of the solvent layers. GPR imaging found significant reflectivity increases due to solvent layer formation during the two week period immediately after the release. These results demonstrated the capacity of GPR profiling for the detection and monitoring of lesser volume DNAPL releases that are more representative of small-scale industrial spills. The GPR imaged solvent layers subsequently reduced in both areal extent and reflectivity after 29 months and almost completely disappeared by the end of the 66 month monitoring period. Total DNAPL mass estimates based on GPR profiling data indicated that the solvent mass was reduced to 34%-36% of its maximum value after 29 months; only 4%-9% of the solvent mass remained in the study area after 66 months. These results are consistent with independent hydrogeological estimates of remaining DNAPL mass based on the downgradient monitoring of the dissolved solvent phase. Hence, we have concluded that the long-term GPR reflectivity changes of the DNAPL layers are likely the result from the dissolution of chlorinated solvents residing in those layers. The long-term monitoring results demonstrated that GPR profiling is a promising non-invasive method for use at DNAPL contaminated sites in sandy aquifers where temporal information about immiscible contaminant mass depletion due to either natural flow or remediation is needed. However, our results also indicated that the GPR signature of older DNAPL impacted zones may not differ greatly from the uncontaminated background if significant mass reduction due to dissolution has occurred. PMID:18258330

Hwang, Yong Keun; Endres, Anthony L; Piggott, Scott D; Parker, Beth L

2008-04-01

246

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

247

Geochemical, isotopic, and dissolved gas characteristics of groundwater in a fractured crystalline-rock aquifer, Savage Municipal Well Superfund site, Milford, New Hampshire, 2011  

USGS Publications Warehouse

Tetrachloroethylene (PCE), a volatile organic compound, was detected in groundwater from deep (more than (>) 300 feet (ft) below land surface) fractures in monitoring wells tapping a crystalline-rock aquifer beneath operable unit 1 (OU1) of the Savage Municipal Well Superfund site (Weston, Inc., 2010). Operable units define remedial areas of contaminant concern. PCE contamination within the fractured-rock aquifer has been designated as a separate operable unit, operable unit 3 (OU3; Weston, Inc., 2010). PCE contamination was previously detected in the overlying glacial sand and gravel deposits and basal till, hereafter termed the Milford-Souhegan glacial-drift (MSGD) aquifer (Harte, 2004, 2006). Operable units 1 and 2 encompass areas within the MSGD aquifer, whereas the extent of the underlying OU3 has yet to be defined. The primary original source of contamination has been identified as a former manufacturing facility—the OK Tool manufacturing facility; hence OU1 sometimes has been referred to as the OK Tool Source Area (New Hampshire Department of Environmental Services, undated). A residential neighborhood of 30 to 40 houses is located in close proximity (one-quarter of a mile) from the PCE-contaminated monitoring wells. Each house has its own water-supply well installed in similar rocks as those of the monitoring wells, as indicated by the New Hampshire State geologic map (Lyons and others, 1997). An investigation was initiated in 2010 by the U.S. Environmental Protection Agency (USEPA) region 1, and the New Hampshire Department of Environmental Services (NHDES) to assess the potential for PCE transport from known contaminant locations (monitoring wells) to the residential wells. The U.S. Geological Survey (USGS) and the NHDES entered into a cooperative agreement in 2011 to assist in the evaluation of PCE transport in the fractured-rock aquifer. Periodic sampling over the last decade by the USEPA and NHDES has yet to detect PCE in groundwater from the residential-supply wells (as of 2012). However, part of assessing the potential for PCE transport involves understanding the origin of the groundwater in the monitoring and residential wells. One of the tools in delineating the movement of groundwater to wells, particularly in complex, highly heterogeneous fractured-rock aquifers, is the understanding of the geochemical and isotopic composition of groundwater (Lipfert and Reeve, 2004; Harte and others, 2012). This report summarizes findings from analyses of geochemical, isotopic, and dissolved gas characteristics of groundwater. Samples of groundwater were collected in 2011 from monitoring wells and nearby residential-supply wells in proximity to OU1.

Harte, Philip T.

2013-01-01

248

Dissolution Coupled Biodegradation of Pce by Inducing In-Situ Biosurfactant Production Under Anaerobic Conditions  

NASA Astrophysics Data System (ADS)

Biosurfactants have proven to enhance the bioavailability and thereby elevate the rate of degradation of Light Non Aqueous Phase Liquids (LNAPLs) such as crude oil and petroleum derivatives. In spite of their superior characteristics, use of these biomolecules for remediation of Dense Non Aqueous Phase Liquids (DNAPLs) such as chlorinated solvents is still not clearly understood. In this present study, we have investigated the fate of tetrachloroethylene (PCE) by inducing in-situ biosurfactants production, a sustainable option which hypothesizes increase in bioavailability of LNAPLs. In order to understand the effect of biosurfactants on dissolution and biodegradation under the inducement of in-situ biosurfactant production, batch experiments were conducted in pure liquid media. The individual influence of each process such as biosurfactant production, dissolution of PCE and biodegradation of PCE were studied separately for getting insights on the synergistic effect of each process on the fate of PCE. Finally the dissolution coupled biodegradation of non aqueous phase PCE was studied in conditions where biosurfactant production was induced by nitrate limitation. The effect of biosurfactants was differentiated by repeating the same experiments were the biosurfactant production was retarded. The overall effect of in-situ biosurfactant production process was evaluated by use of a mathematical model. The process of microbial growth, biosurfactant production, dissolution and biodegradation of PCE were translated as ordinary differential equations. The modelling exercise was mainly performed to get insight on the combined effects of various processes that determine the concentration of PCE in its aqueous and non-aqueous phases. Model simulated profiles of PCE with the kinetic coefficients evaluated earlier from individual experiments were compared with parameters fitted for observations in experiments with dissolution coupled biodegradation process using optimization routines. Complete disappearance of PCE from DNAPL and aqueous phase was observed in a span of 14 days in systems triggered with biosurfactant production through enhanced dissolution and biodegradation. Synergistic effect of dissolution process towards biodegradation was observed as bioavailability of PCE was increased by 3.1 times in systems with biosurfactant production. Modelling studies illustrate that biodegradation on the other hand synergistically enhanced dissolution by elevating the dissolution rates by 1.4 times. This study also suggests a mass transfer phenomenon is greatly influenced not only by surface active molecules but by microbes as well.

Dominic, J.; Nambi, I. M.

2013-12-01

249

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

250

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

251

Iron-carbon composites for the remediation of chlorinated hydrocarbons  

NASA Astrophysics Data System (ADS)

This research is focused on engineering submicron spherical carbon particles as effective carriers/supports for nanoscale zerovalent iron (NZVI) particles to address the in situ remediation of soil and groundwater chlorinated contaminants. Chlorinated hydrocarbons such as trichloroethylene (TCE) and tetrachloroethylene (PCE) form a class of dense non-aqueous phase liquid (DNAPL) toxic contaminants in soil and groundwater. The in situ injection of NZVI particles to reduce DNAPLs is a potentially simple, cost-effective, and environmentally benign technology that has become a preferred method in the remediation of these compounds. However, unsupported NZVI particles exhibit ferromagnetism leading to particle aggregation and loss in mobility through the subsurface. This work demonstrates two approaches to prepare carbon supported NZVI (iron-carbon composites) particles. The objective is to establish these iron-carbon composites as extremely useful materials for the environmental remediation of chlorinated hydrocarbons and suitable materials for the in situ injection technology. This research also demonstrates that it is possible to vary the placement of iron nanoparticles either on the external surface or within the interior of carbon microspheres using a one-step aerosol-based process. The simple process of modifying iron placement has significant potential applications in heterogeneous catalysis as both the iron and carbon are widely used catalysts and catalyst supports. Furthermore, the aerosol-based process is applied to prepare new class of supported catalytic materials such as carbon-supported palladium nanoparticles for ex situ remediation of contaminated water. The iron-carbon composites developed in this research have multiple functionalities (a) they are reactive and function effectively in reductive dehalogenation (b) they are highly adsorptive thereby bringing the chlorinated compound to the proximity of the reactive sites and also serving as adsorption materials for decontamination (c) they are of the optimal size for transport through sediments (d) they have amphiphilic chemical functionalities that help stabilize them when they reach the DNAPL target zones. Finally, the iron-carbon composite microspheres prepared through aerosol-based process can used for in situ injection technology as the process is conductive to scale-up and the materials are environmentally benign.

Sunkara, Bhanu Kiran

252

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

253

Ground-water quality in the Santa Ana Watershed, California : overview and data summary  

USGS Publications Warehouse

Water-quality samples were collected from 207 wells in the Santa Ana Basin in the Coastal Range Province of southern California to assess the occurrence and distribution of dissolved constituents in ground water as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program. These wells were sampled during eight studies from 1999 to 2001 that were designed to sample the used water resource at different scales: (1) three studies characterized water quality at a regional scale; (2) two studies focused on spatial and temporal variations in water quality along flow paths; (3) a land-use study focused on evaluation of water quality in shallow ground water; and (4) two studies assessed aquifer susceptibility to contamination. The Santa Ana Basin is divided into the Coastal Basin, the Inland Basin, and the San Jacinto Basin. The Coastal Basin includes a relatively small unconfined recharge area and a relatively large confined area where ground-water pumping is the primary source of discharge. Land use is almost entirely urban. The Inland Basin is predominantly unconfined and land use is urban and agricultural. The San Jacinto Basin is largely unconfined and land use is mostly agricultural. Water-quality data discussed in this report are compared with U.S. Environmental Protection Agency (EPA) drinking-water standards, both primary and secondary. Most exceedances of maximum contaminant levels (MCLs) occurred in the shallow, coastal monitoring wells that tap ground water not used for water supply. Water from several irrigation wells in the Inland and San Jacinto basins exceeded the 10 mg/L (milligrams per liter) MCL for nitrate. Water from some wells exceeded secondary MCLs for manganese (50 ?g/L [micrograms per liter]) and iron (300 ?g/L) and (or) proposed MCLs for arsenic (10 ?g/L) and uranium (30 ?g/L). Of the 94 production wells sampled for trace elements, 3 irrigation wells in the Coastal Basin produced water that exceeded the secondary MCL for manganese. Water from production wells sampled in all three subbasins exceeded the proposed MCL for radon (300 pCi/L [picocuries per liter]). Pesticides were detected above the laboratory reporting limit (LRL) in 50 percent of the production and monitoring wells sampled in the Santa Ana Basin. Deethylatrazine, simazine, atrazine, tebuthiuron, and prometon were the five most commonly detected pesticides in the current USGS studies. All pesticide concentrations detected in these studies were below MCLs established by the EPA. Volatile organic compounds (VOCs) were detected in 115 wells (56 percent) of the 207 wells sampled. Of the 38 VOCs detected, only 13 were detected in more than five wells. The most commonly detected VOCs, in order of detection frequency, were chloroform; trichloroethlyene, TCE; 1,1,1-trichloroethane, TCA; trichlorofluoromethane, CFC 11; 1,1,2-trichloro-1,2,2-trifluoroethane, CFC 113; tetrachloroethylene, PCE; bromodichloromethane; methyl tert-butyl ether, MTBE; 1,1-dichloroethene, 1-1-DCE; and 1,2- dichloroethene, 1,2-DCE. The only exceedances of EPA MCLs for VOCs occurred in six irrigation wells and in two deep monitoring wells sampled in the Inland Basin.

Hamlin, Scott N.; Belitz, Kenneth; Kraja, Sarah; Dawson, Barbara

2002-01-01

254

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

255

Evaluation of volatile organic compounds in two Mojave Desert basins-Mojave River and Antelope Valley-in San Bernardino, Los Angeles, and Kern Counties, California, June-October 2002  

USGS Publications Warehouse

The California Aquifer Susceptibility Assessment of the Ground-Water Ambient Monitoring and Assessment Program was developed to assess water quality and susceptibility of ground-water resources to contamination from surficial sources. This study focuses on the Mojave River and the Antelope Valley ground-water basins in southern California. Volatile organic compound (VOC) data were evaluated in conjunction with tritium data to determine a potential correlation with aquifer type, depth to top of perforations, and land use to VOC distribution and occurrence in the Mojave River and the Antelope Valley Basins. Detection frequencies for VOCs were compiled and compared to assess the distribution in each area. Explanatory variables were evaluated by comparing detection frequencies for VOCs and tritium and the number of compounds detected. Thirty-three wells were sampled in the Mojave River Basin (9 in the floodplain aquifer, 15 in the regional aquifer, and 9 in the sewered subset of the regional aquifer). Thirty-two wells were sampled in the Antelope Valley Basin. Quality-control samples also were collected to identify, quantify, and document bias and variability in the data. Results show that VOCs generally were detected slightly more often in the Antelope Valley Basin samples than in the Mojave River Basin samples. VOCs were detected more frequently in the floodplain aquifer than in the regional aquifer and the sewered subset. Tritium was detected more frequently in the Mojave River Basin samples than in the Antelope Valley Basin samples, and it was detected more frequently in the floodplain aquifer than in the regional aquifer and the sewered subset. Most of the samples collected in both basins for this study contained old water (water recharged prior to 1952). In general, in these desert basins, tritium need not be present for VOCs to be present. When VOCs were detected, young water (water recharge after 1952) was slightly more likely to be contaminated than old water. Trihalomethanes (THMs) were detected less frequently in the Mojave River Basin samples than in the Antelope Valley Basin samples. The THMs that were detected in the Mojave River Basin were detected more frequently in the floodplain aquifer than in the regional aquifer and sewered subset. Solvents were detected more frequently in the Mojave River samples than in the Antelope Valley samples. In the Mojave River Basin samples, solvents were detected less frequently in the floodplain aquifer than in the regional aquifer and the sewered subset. Benzene, toluene, ethylbenzene and xylene (BTEX) were not detected in either study area. Methyl tert-butyl ether (MTBE) was detected in one sample from both the Mojave River and Antelope Valley Basins. The most frequently detected compound (detected in more than 10 percent of the wells) in the Mojave River Basin was chloroform. The two most frequently detected compounds in the Antelope Valley Basin were chloroform and tetrachloroethylene (PCE). In the Mojave River Basin, aquifer type and land use within 1,640 ft (500 m) of the well head were not statistically correlated with the number of VOCs detected, although VOCs were detected more frequently in the floodplain aquifer than in the regional aquifer and the sewered subset. Depth to the top of the perforations was an explanatory factor for the number of VOCs detected in the Mojave River Basin; the detection frequency was greater for shallow wells than for deep wells. In the Antelope Valley Basin, neither aquifer type, depth to the top of the perforations, nor land use within 1,640 ft of the well head were explanatory factors for the number of VOCs detected. Although aquifer type and depth to top of the perforations did explain the presence of tritium in the Mojave River Basin, land use within 1,640 ft of the well head was not a statistically significant explanatory factor for the presence of tritium in this basin. Aquifer type, depth to the top of the perfora

Densmore, Jill N.; Belitz, Kenneth; Wright, Michael T.; Dawson, Barbara J.; Johnson, Tyler

2005-01-01

256

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

257

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

258

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

USGS Publications Warehouse

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

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

1998-01-01

259

Assessing the susceptibility to contamination of two aquifer systems used for public water supply in the Modesto and Fresno metropolitan areas, California, 2001 and 2002  

USGS Publications Warehouse

Ground-water samples were collected from 90 active public supply wells in the Fresno and Modesto metropolitan areas as part of the California Aquifer Susceptibility (CAS) program. The CAS program was formed to examine the susceptibility to contamination of aquifers that are tapped by public supply wells to serve the citizens of California. The objectives of the program are twofold: (1) to evaluate the quality of ground water used for public supply using volatile organic compound (VOC) concentrations in ground-water samples and (2) to determine if the occurrence and distribution of low level VOCs in ground water and characteristics, such as land use, can be used to predict aquifer susceptibility to contamination from anthropogenic activities occurring at, or near, land surface. An evaluation was made of the relation between VOC occurrence and the explanatory variables: depth to the top of the uppermost well perforation, land use, relative ground-water age, high nitrate concentrations, density of leaking underground fuel tanks (LUFT), and source of recharge water. VOCs were detected in 92 percent of the wells sampled in Modesto and in 72 percent of the wells sampled in Fresno. Trihalomethanes (THM) and solvents were frequently detected in both study areas. Conversely, the gasoline components?benzene, toluene ethylbenzene, and xylenes (BTEX)?were rarely, if at all, detected, even though LUFTs were scattered throughout both study areas. The rare occurrence of BTEX compounds may be the result of their low solubility and labile nature in the subsurface environment. Samples were analyzed for 85 VOCs; 25 were detected in at least one sample. The concentrations of nearly all VOCs detected were at least an order of magnitude below action levels set by drinking water standards. Concentrations of four VOCs exceeded federal and state maximum contaminant levels (MCL): the solvent trichloroethylene (TCE) and the fumigant 1, 2-dibromo-3-chloropropane (DBCP) in Fresno, and the solvents TCE and tetrachloroethylene (PCE) in Modesto. Chloroform, which is a by product of water disinfection and a constituent used in industrial processes since the 1920s, was the most frequently detected compound, whereas the gasoline oxygenate methyl tert-butyl ether (MTBE), which has been in widespread production and use only since the 1990s, was detected in only 2 percent of the samples. Downward migration of contaminants appears to be a viable pathway of contamination in the unconfined and semi-confined aquifers underlying the Fresno and Modesto study areas. Within the individual study areas, VOCs were detected more frequently and in greater numbers in shallower wells than in deeper wells. Additionally, VOCs were detected more frequently and in greater numbers in Modesto than in Fresno. Wells sampled in Modesto were significantly shallower than the wells sampled in Fresno; the other explanatory variables examined in this report were not significantly different between the two study areas. VOCs occurred more frequently in younger ground water (water recharged after 1952) than in older ground water (water recharged prior to 1952). Additionally, wells withdrawing younger ground water had a higher number of VOCs detected per well than did wells withdrawing older ground water. Younger ground water was at or near the land surface during a period when VOCs came into widespread production and use. Therefore, wells from which younger ground water is withdrawn may be more susceptible to contamination. Of the explanatory variables examined in this study, land use was the best predictor of aquifer susceptibility in the Fresno and Modesto study areas. VOCs were detected more frequently in wells located in heavily urbanized areas. The number of VOCs detected in ground water was positively correlated to the degree of urbanization. VOCs are produced and used primarily in urban land use settings; therefore, aquifers underlying urban areas may be more susceptible to

Wright, Michael T.; Belitz, Kenneth; Johnson, Tyler

2004-01-01

260

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

261

Final Technical Report: Effects of Impurities on Fuel Cell Performance and Durability  

SciTech Connect

The main objectives of this project were to investigate the effect of a series of potential impurities on fuel cell operation and on the particular components of the fuel cell MEA, to propose (where possible) mechanism(s) by which these impurities affected fuel cell performance, and to suggest strategies for minimizing these impurity effects. The negative effect on Pt/C was to decrease hydrogen surface coverage and hydrogen activation at fuel cell conditions. The negative effect on Nafion components was to decrease proton conductivity, primarily by replacing/reacting with the protons on the Bronsted acid sites of the Nafion. Even though already well known as fuel cell poisons, the effects of CO and NH3 were studied in great detail early on in the project in order to develop methodology for evaluating poisoning effects in general, to help establish reproducibility of results among a number of laboratories in the U.S. investigating impurity effects, and to help establish lower limit standards for impurities during hydrogen production for fuel cell utilization. New methodologies developed included (1) a means to measure hydrogen surface concentration on the Pt catalyst (HDSAP) before and after exposure to impurities, (2) a way to predict conductivity of a Nafion membranes exposed to impurities using a characteristic acid catalyzed reaction (methanol esterification of acetic acid), and, more importantly, (3) application of the latter technique to predict conductivity on Nafion in the catalyst layer of the MEA. H2-D2 exchange was found to be suitable for predicting hydrogen activation of Pt catalysts. The Nafion (ca. 30 wt%) on the Pt/C catalyst resides primarily on the external surface of the C support where it blocks significant numbers of micropores, but only partially blocks the pore openings of the meso- and macro-pores wherein lie the small Pt particles (crystallites). For this reason, even with 30 wt% Nafion on the Pt/C, few Pt sites are blocked and, hence, are accessible for hydrogen activation. Of the impurities studied, CO, NH3, perchloroethylene (also known as tetrachloroethylene), tetrahydrofuran, diborane, and metal cations had significant negative effects on the components in a fuel cell. While CO has no effect on the Nafion, it significantly poisons the Pt catalyst by adsorbing and blocking hydrogen activation. The effect can be reversed with time once the flow of CO is stopped. NH3 has no effect on the Pt catalyst at fuel cell conditions; it poisons the proton sites on Nafion (by forming NH4+ cations), decreasing drastically the proton conductivity of Nafion. This poisoning can slowly be reversed once the flow of NH3 is stopped. Perchloroethylene has a major effect on fuel cell performance. Since it has little/no effect on Nafion conductivity, its poisoning effect is on the Pt catalyst. However, this effect takes place primarily for the Pt catalyst at the cathode, since the presence of oxygen is very important for this poisoning effect. Tetrahydrofuran was shown not to impact Nafion conductivity; however, it does affect fuel cell performance. Therefore, its primary effect is on the Pt catalyst. The effect of THF on fuel cell performance is reversible. Diborane also can significant affect fuel cell performance. This effect is reversible once diborane is removed from the inlet streams. H2O2 is not an impurity usually present in the hydrogen or oxygen streams to a fuel cell. However, it is generated during fuel cell operation. The presence of Fe cations in the Nafion due to system corrosion and/or arising from MEA production act to catalyze the severe degradation of the Nafion by H2O2. Finally, the presence of metal cation impurities (Na+, Ca 2+, Fe3+) in Nafion from MEA preparation or from corrosion significantly impacts its proton conductivity due to replacement of proton sites. This effect is not reversible. Hydrocarbons, such as ethylene, might be expected to affect Pt or Nafion but do not at a typical fuel cell temperature of 80oC. In the presence of large quantities of hydrogen on the anode side, ethylene i

James G. Goodwin, Jr.; Hector Colon-Mercado; Kitiya Hongsirikarn; and Jack Z. Zhang

2011-11-11

262

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

263

California GAMA program: ground-water quality data in the San Diego drainages hydrogeologic province, California, 2004  

USGS Publications Warehouse

Because of concerns over ground-water quality, the California State Water Resources Control Board (SWRCB), in collaboration with the U.S. Geological Survey and Lawrence Livermore National Laboratory, has implemented the Ground-Water Ambient Monitoring and Assessment (GAMA) Program. A primary objective of the program is to provide a current assessment of ground-water quality in areas where public supply wells are an important source of drinking water. The San Diego GAMA study unit was the first region of the state where an assessment of ground-water quality was implemented under the GAMA program. The San Diego GAMA study unit covers the entire San Diego Drainages hydrogeologic province, and is broken down into four distinct hydrogeologic study areas: the Temecula Valley study area, the Warner Valley study area, the Alluvial Basins study area, and the Hard Rock study area. A total of 58 ground-water samples were collected from public supply wells in the San Diego GAMA study unit: 19 wells were sampled in the Temecula Valley study area, 9 in the Warner Valley study area, 17 in the Alluvial Basins study area, and 13 in the Hard Rock study area. Over 350 chemical and microbial constituents and water-quality indicators were analyzed for in this study. However, only select wells were measured for all constituents and water-quality indicators. Results of analyses were calculated as detection frequencies by constituent classification and by individual constituents for the entire San Diego GAMA study unit and for the individual study areas. Additionally, concentrations of constituents that are routinely monitored were compared to maximum contaminant levels (MCL) and secondary maximum contaminant levels (SMCL). Concentrations of constituents classified as 'unregulated chemicals for which monitoring is required' (UCMR) were compared to the 'detection level for the purposes of reporting' (DLR). Eighteen of the 88 volatile organic compounds (VOCs) and gasoline oxygenates analyzed for were detected in ground-water samples. Twenty-eight wells sampled in the San Diego GAMA study had at least a single detection of VOCs or gasoline oxygenates. These constituents were most frequently detected in the Alluvial Basin study area (11 of 17 wells), and least frequently detected in the Warner Valley study area (one of nine wells). Trihalomethanes (THMs) were the most frequently detected class of VOCs (18 of 58 wells). The most frequently detected VOCs were chloroform (18 of 58 wells), bromodichloromethane (8 of 58 wells), and methyl tert-butyl ether (MTBE) (7 of 58 wells). Three VOCs were detected at concentrations greater than their MCLs. Tetrachloroethylene (PCE) and trichloroethylene (TCE) were detected in one well in the Hard Rock study area at concentrations of 9.75 and 7.27 micrograms per liter (?g/L), respectively; the MCL for these compounds is 5 ?g/L. MTBE was detected in one well in the Alluvial Basins study area at a concentration of 28.3 ?g/L; the MCL for MTBE is 13 ?g/L. Twenty-one of the 122 pesticides and pesticide degradates analyzed for were detected in ground-water samples. Pesticide or pesticide degradates were detected in 33 of 58 wells sampled, and were most frequently detected in the Temecula Valley study area wells (9 of 14 wells), and least frequently in the Warner Valley study area wells (3 of 9 wells). Herbicides were the most frequently detected class of pesticides (31 of 58 wells), and simazine was the most frequently detected compound (27 of 58 wells), followed by deethylatrazine (14 of 58 wells), prometon (10 of 58 wells), and atrazine (9 of 58 wells). None of the pesticides detected in ground-water samples had concentrations that exceeded MCLs. Eight waste-water indicator compounds were detected in ground-water samples. Twenty-one of 47 wells sampled for waste-water indicator compounds had at least a single detection. Waste-water indicator compounds were detected most frequently in the Allu

Wright, Michael T.; Belitz, Kenneth; Burton, Carmen A.

2005-01-01

264

Changes in Groundwater Flow and Volatile Organic Compound Concentrations at the Fischer and Porter Superfund Site, Warminster Township, Bucks County, Pennsylvania, 1993-2009  

USGS Publications Warehouse

The 38-acre Fischer and Porter Company Superfund Site is in Warminster Township, Bucks County, Pa. Historically, as part of the manufacturing process, trichloroethylene (TCE) degreasers were used for parts cleaning. In 1979, the Bucks County Health Department detected TCE and other volatile organic compounds (VOCs) in water from the Fischer and Porter on-site supply wells and nearby public-supply wells. The Fischer and Porter Site was designated as a Superfund Site and placed on the National Priorities List in September 1983. A 1984 Record of Decision for the site required the Fischer and Porter Company to pump and treat groundwater contaminated by VOCs from three on-site wells at a combined rate of 75 gallons per minute to contain groundwater contamination on the property. Additionally, the Record of Decision recognized the need for treatment of the water from two nearby privately owned supply wells operated by the Warminster Heights Home Ownership Association. In 2004, the Warminster Heights Home Ownership Association sold its water distribution system, and both wells were taken out of service. The report describes changes in groundwater levels and contaminant concentrations and migration caused by the shutdown of the Warminster Heights supply wells and presents a delineation of the off-site groundwater-contamination plume. The U.S. Geological Survey (USGS) conducted this study (2006-09) in cooperation with the U.S. Environmental Protection Agency (USEPA). The Fischer and Porter Site and surrounding area are underlain by sedimentary rocks of the Stockton Formation of Late Triassic age. The rocks are chiefly interbedded arkosic sandstone and siltstone. The Stockton aquifer system is comprised of a series of gently dipping lithologic units with different hydraulic properties. A three-dimensional lithostratigraphic model was developed for the site on the basis of rock cores and borehole geophysical logs. The model was simplified by combining individual lithologic units into generalized units representing upward fining sedimentary cycles capped by a siltstone bed. These cycles were labeled units 1 through 8 and are called stratigraphic units in this report. Groundwater in the unweathered zone mainly moves through a network of interconnecting secondary openings--bedding-plane fractures and joints. Groundwater generally is unconfined in the shallower part of the aquifer and confined or semiconfined in the deeper part of the aquifer. The migration of VOCs from the Fischer and Porter Site source area is influenced by geologic and hydrologic controls. The hydrologic controls have changed with time. Stratigraphic units 2 and 3 crop out beneath the former Fischer and Porter plant. VOCs originating at the plant source area entered these stratigraphic units and moved downdip to the northwest. When the wells at and in the vicinity of the site were initially sampled in 1979-80, three public-supply wells (BK-366, BK-367, MG-946) and three industrial-supply wells (BK-368, BK-370, and BK-371) were pumping. Groundwater contaminated with VOCs flowed downdip and then northeast along strike toward well BK-366, downdip toward well BK-368, and downdip and then west along strike toward well MG-946. The long axis of the TCE plume is oriented about N. 18? W. in the direction of dip. In 1979-80, the leading edge of the plume was about 3,500 feet wide. With the cessation of pumping of the supply wells in 2004, the size of the plume has decreased. In 2007-09, the plume was approximately 2,000 feet long and 2,000 feet wide at the leading edge. On the western side of the site, TCE and tetrachloroethylene (PCE) appear to be moving downdip though stratigraphic unit 3. The downdip extent of TCE and PCE migration extended approximately 550 feet off-site to the northwest and 750 feet off-site to the north. TCE concentrations in water samples from wells at the western site boundary increased from 1996 to 2007. On the northern side of the site, TCE and P

Sloto, Ronald A.

2010-01-01

265

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 70ºN, 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