Download or read book Estimation of Volatile Organic Compound Concentrations in the Vadose Zone written by RK. Sextro and published by . This book was released on 1996 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Obtaining defensible and conservative estimates of the nature, extent and concentration of volatile organic compounds (VOCs) in the vadose zone is extremely important when formulating the conceptual model of the site, when performing risk assessments, for estimating contaminant mass, for assessing remedial alternatives, for selecting target areas for cleanup, and/or for making no further action/investigation decisions. Studies have shown that soil gas analytical results provide both a more complete indication of the VOCs present and a higher estimate of their respective concentrations in the vadose zone than the analysis of soil samples alone. For the past several years deep downhole (to 30+ meters) soil gas sampling and analysis has been performed by various consultants during remedial investigations (RIs) and remedial actions (RAs) of the vadose zone at McClellan Air Force Base. A number of these soil gas results have been confirmed by the concurrent collection and analysis (for VOCs) of soil samples (preserved by either refrigeration to 4 degrees centigrade or refrigeration combined with methanol preservation). The use of this VOC sampling and analysis strategy has resulted in the optimization of VOC sampling and analysis procedures, in a better understanding of the relationship between the concentration of VOCs in soil gas and in the soil, and in a more accurate and comprehensive conceptual model for VOC contamination in the vadose zone. The paper will present the methodologies used by the various consultants for sample collection, preservation, and in the analysis of soil gas and soil samples, present the results of a focused QC study on soil gas sampling and analysis, and discuss the correlation between the soil gas and soil matrix analytical results. The current and future strategies for the sampling, analysis, and estimation of VOCs in the vadose zone during RIs and RAs will also be presented.
Download or read book Estimating the Total Concentration of Volatile Organic Compounds in Soil written by Alan Dole Hewitt and published by . This book was released on 1997 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Volatile Organic Compounds in the Environment written by Wun-cheng Wang and published by ASTM International. This book was released on 1996 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: Papers delivered at the symposium of the same name, April 1994, by speakers from seven nations. Twenty presentations are arranged under six topics: regulation and assessment, air quality, environmental fate, environmental measurement, environmental monitoring, and control and remediation. A sampling
Download or read book Evaluation of a Diffusion Sampling Method for Determining Concentrations of Volatile Organic Compounds in Ground Water Hanscom Air Force Base Bedford Massachusetts written by Peter Eaton Church and published by . This book was released on 2000 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Evaluation of Vapor Extraction of Vadose Zone Contamination written by and published by . This book was released on 1992 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: An in-depth analysis of vapor extraction for remediation of soils contaminated with volatile organic compounds (VOCS) was conducted at 13 sites. The effectiveness of vapor extraction systems (VES) was evaluated on the basis of soil concentrations of VOCs and soil-gas concentrations of VOC's. The range of effectiveness was found to be 64%--99% effective in removing organic contaminants from soil. At nine of the 13 sites studied in this report, vapor extraction was found to be effective in reducing VOC cooncentrations by at least 90%. At the remaining four sites studied, vapor extraction was found to reduce VOC concentrations by less than 90%. Vapor extraction is ongoing at two of these sites. At a third, the ineffectiveness of the vapor extraction is attributed to the presence of hot spots'' of contamination. At the fourth site, where performance was found to be relatively poor, the presence of geological tar deposits at the site is thought to be a major factor in the ineffectiveness.
Download or read book Mass Transport of Volatile Organic Compounds Between the Saturated and Vadose Zones written by Monte S. Harner and published by . This book was released on 1996-12-01 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volatile organic compounds (VOCs) dissolved in the saturated zone are transported into the vadose zone primarily by gaseous phase diffusion. If the saturated zone is remediated, VOCs present in the vadose zone may become a secondary source of contamination for the groundwater The amount of VOCs that remain in the vadose zone is dependent on site hydrology, soil properties, and the chemical properties of the contaminants. The purpose of this study was to determine what conditions caused VOC concentrations in the vadose zone to significantly recontaminate the saturated zone. A one-dimensional numerical model was developed to investigate the transport of a VOC, trichioroethylene, between the saturated and vadose zones under a variety of conditions. The model featured steady-state unsaturated water flow and transient contaminant transport Transport mechanisms included aqueous phase advection-dispersion and gaseous phase diffusion. Partitioning between the water, gas, and soil compartments were modeled as equilibrium processes. Sensitivity analyses were performed on several variables including soil type (homogeneous and heterogeneous profiles), water infiltration rate and vadose zone depth. Results indicated that recontamination was most significant rate, and vadose zone depth. Results indicated that recontamination was most significant in the presence of heterogeneous soils, low infiltration rates and deep vadose zones.
Download or read book Behavior and Determination of Volatile Organic Compunds in Soil written by Marti Minnich and published by . This book was released on 1993 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vapor fortified QA QC Samples for the Analysis of Volatile Organic Compounds written by Alan D. Hewitt and published by . This book was released on 1994 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Vadose Zone Characterization Monitoring written by L. Gray Wilson and published by CRC Press. This book was released on 2018-05-02 with total page 752 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is written in a simple, straightforward manner without complicated mathematical derivatives. Compiled by experienced practitioners, this guide covers topics such as basic principles of vadose zone hydrology and prevalent monitoring techniques. Case studies present actual field experiences for the benefit of the reader. The Handbook provides practitioners with the information they need to fully understand the principles, advantages, and limitations of the monitoring techniques that are available. The Handbook of Vadose Zone Characterization & Monitoring expands and consolidates the useful and succint information contained in various ASTM documents, EPA manuals, and other similar texts on the subject, making it an invaluable aid to new practioners and a useful reference for seasoned veterans in the field.
Download or read book Handbook of Vadose Zone Characterization Monitoring written by L. Gray Wilson and published by CRC Press. This book was released on 1994-12-20 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is written in a simple, straightforward manner without complicated mathematical derivatives. Compiled by experienced practitioners, this guide covers topics such as basic principles of vadose zone hydrology and prevalent monitoring techniques. Case studies present actual field experiences for the benefit of the reader. The Handbook provides practitioners with the information they need to fully understand the principles, advantages, and limitations of the monitoring techniques that are available. The Handbook of Vadose Zone Characterization & Monitoring expands and consolidates the useful and succint information contained in various ASTM documents, EPA manuals, and other similar texts on the subject, making it an invaluable aid to new practioners and a useful reference for seasoned veterans in the field.
Download or read book Laboratory Study of Volatile Organic Compound Partitioning Vapor aqueous soil written by Alan Dole Hewitt and published by . This book was released on 1998 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation Of Volatile Organic Compound Voc Blank Data And Application Of Study Reporting Levels To Groundwater Data Collected For The California Gama Priority Basin Project May 2004 Through September 2010 written by Miranda S. Fram and published by CreateSpace. This book was released on 2014-07-11 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volatile organic compounds (VOCs) were analyzed in quality-control samples collected for the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project. From May 2004 through September 2010, a total of 2,026 groundwater samples, 211 field blanks, and 109 source-solution blanks were collected and analyzed for concentrations of 85 VOCs. Results from analyses of these field and source-solution blanks and of 2,411 laboratory instrument blanks during the same time period were used to assess the quality of data for the 2,026 groundwater samples. Eighteen VOCs were detected in field blanks or source-solution blanks: acetone, benzene, bromodichloromethane, 2-butanone, carbon disulfide, chloroform, 1,1-dichloroethene, dichloromethane, ethylbenzene, tetrachloroethene, styrene, tetrahydrofuran, toluene, trichloroethene, trichlorofluoromethane, 1,2,4-trimethylbenzene, m- and p-xylenes, and o-xylene.
Download or read book Special Report written by and published by . This book was released on 1993 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spatial and Temporal Variation in the Concentration of Volatile Organic Compounds in the Vadose Zone and the Water Table Region at Magen Nahalat Itzhak Tel Aviv written by Hagit Lev-Wiener and published by . This book was released on 2006 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Laboratory Study of Volatile Organic Compound Partitioning written by Alan Dole Hewitt and published by . This book was released on 1998 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: A laboratory experiment measured the concentrations of volatile organic compounds (VOCs) existing in a vapor, water, and bulk soil media after several weeks of exposure to a contaminant source. The experimental design included quiescent conditions, hydrated mineral surfaces, and a constant temperature of 11 +/- 1 deg C. The findings show that similar to Henry's law, fairly constant ratios are likely to exist between soil vapor and bulk soil VOC concentrations. These results are encouraging for those attempting to use active soil gas measurements to predict bulk VOC concentrations in the vadose zone.
Download or read book Natural Attenuation Assessment of Multiple VOCs in a Deep Vadose Zone written by and published by . This book was released on 2000 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fate of six volatile organic compounds (VOC) in a 150-meter deep vadose zone was examined in support of a RCRA Corrective Measures Study of the Chemical Waste Landfill at Sandia National Laboratories, Albuquerque, New Mexico. The study focused on the modeling of potential future transport of the VOCs to exposure media upon the completion of two separate voluntary corrective measures--soil vapor extraction and landfill excavation--designed to significantly reduce contaminant levels in subsurface soils. modeling was performed with R-UNSAT, a finite-difference simulator that was developed by the U.S. Geological Survey. R-UNSAT facilitated a relatively unique and comprehensive assessment of vapor transport because it (1) simulated the simultaneous movement of all six VOCs, taking into account each constituent's diffusion coefficient as affected by its mole fraction within a mixture of chemicals, and (2) permitted simultaneous assessment of risk to human health via volatilization (air) and drinking water (groundwater) pathways. Modeling results suggested that monitored natural attenuation would represent a viable remedial alternative at the landfill after both voluntary corrective measures were completed.
Download or read book VADOSE ZONE MODELING OF ORGANIC POLLUTANTS written by S. C. Hern and published by Springer. This book was released on 1986-10 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of chemical fate and transport modeling in the vadose zone. Chemical processes, parameter estimation, and variability in the vadose zone. Mathematical derivation of chemical transport equations.
