Download or read book Analysis of Volatile Organic Compounds VOCs in Soil Via Passive Sampling written by and published by . This book was released on 2015 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Passive sampling has been used as a qualitative and semi-quantitative method in detecting volatile organic compound (VOCs) concentrations in soil vapors or water. Passive sampling for soil vapor takes an absorptive material and places it underground for a period of time to allow the VOCs to diffuse into the absorptive materials. In this report, I use low density polyethylene (PE) as the absorptive material and determine two key parameters for passive sampling: the PE-water partition coefficient (Kpew) and diffusion coefficient in PE (Dpe). These two parameters help passive sampling to transition from a qualitative method to a quantitative method. The report describes the steps used to carry out the experiments, gives the results for several specific VOCs, and makes an attempt to draw more general conclusions on how to estimate these two parameters according to some other well-known properties.

Download or read book Quantitative Analysis of Volatile Organic Compounds VOCs in Soil Via Passive Sampling written by David Gannon Jensen and published by . This book was released on 2015 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The potential for the release of volatile organic compounds (VOCs) to our natural environment is pervasive. However, the ability to accurately measure and predict VOC soil vapor concentrations is still limited. A polyethylene (PE) quantitative passive sampler using performance reference compounds and deployed via a hand driven probe is proposed as a solution. Additionally, a 1D diffusion mass transfer model was developed in MATLAB to predict the mass uptake into the PE sampler over time. The model was then implemented to investigate the effects of PE size and deployment time on the detection limit of BTEX compounds. Preliminary testing of the deployment probe indicates that a design to secure the PE around the outside of a driven rod must include a protective cover over the PE during insertion. A perforated pipe design is suggested. After deployment and recovery, the PE is extracted into water. The extraction water is then analyzed by direct aqueous injection to GC/FID. The minimum concentration detectable in soil vapors, by this PE passive sampling method, was determined to be the product of the target compound's air-water partitioning coefficient and the analytical detection limit. Assuming a 5 ng/mL analytical detection limit, the minimum soil vapor detection limit for toluene was approximately 1.25 mg/m 3. This limit would be similar for all BTEX compound and is above sub-slab vapor intrusion screening levels for the more toxic compounds such as benzene. This indicates that direct aqueous injection provides insufficient sensitivity and that purge and trap concentrations of VOCs is likely needed. It was also determined that a PE sampler, with dimensions as small as 5"x5/8"x0.0005", could theoretically reach 10 mg/m 3 sensitivity within a 1 h deployment time. This result suggests potential applications of the sampler for rapid and accurate site characterization of BTEX compounds.

Download or read book Soil Sampling and Analysis for Volatile Organic Compounds written by and published by . This book was released on 1991 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Soil Sampling and Analysis for Volatile Organic Compounds written by and published by . This book was released on 1991 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Benchtop Testing of Polyethylene Passive Sampling Towards a Quantitative Analysis of Volatile Organic Compounds VOCs in Soil Vapours written by Yu Xiang Jaren Soo and published by . This book was released on 2015 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: The feasibility of polyethylene (PE) as a passive sampler for quantitative analysis of volatile organic compounds (VOCs) was analysed in this work by means of a benchtop testing. A benchtop physical model was setup, which consisted of a jar of glass beads or sand, containing a known mass of toluene as the compound of concern (COC). A beaker of water was placed in the physical model as a second form of measurement of toluene concentration in the air. The concentration of toluene in the air of the physical model was measured using the PE passive sampler and compared to results found by measurement toluene in water in the beaker. The PE-inferred vapour concentrations were consistent with the measurements in the water. With benzene, toluene, ethylbenzene and o-xylene (BTEX) selected to be quantified in the actual soil, both the PE passive sampler and the water-based measurement showed inconsistency in contrast to previous experiments with glass beads and sand. This inconsistency could probably be due to the presence of biodegradation. Nonetheless, if proved consistent in future, PE passive sampling can also be used to estimate the concentrations of compounds based on molecular weight in absence of known literature values of required parameters.

Download or read book Establishing a Relationship Between Passive Soil Vapor and Grab Sample Techniques for Determining Volatile Organic Compounds written by Alan Dole Hewitt and published by . This book was released on 1996 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multidepth Soil Gas Analyses Using Passive and Dynamic Sampling Techniques written by Thomas F. Zdeb and published by . This book was released on 1989 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Demonstration and Validation of the Use of Passive Samplers for Monitoring Soil Vapor Intrusion to Indoor Air written by Todd Arthur McAlary and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis documents a demonstration/validation of passive diffusive samplers for assessing soil vapor, indoor air and outdoor air concentrations of volatile organic compounds (VOCs) at sites with potential human health risks attributable to subsurface vapor intrusion to indoor air. The study was funded by the United States (U.S.) Department of Defense (DoD) and the U.S. Department of the Navy (DoN). The passive samplers tested included: SKC Ultra and Ultra II, Radiello®, Waterloo Membrane Sampler (WMS), Automated Thermal Desorption (ATD) tubes, and 3M OVM 3500. The program included laboratory testing under controlled conditions for 10 VOCs (including chlorinated ethenes, ethanes, and methanes, as well as aromatic and aliphatic hydrocarbons), spanning a range of properties and including some compounds expected to pose challenges (naphthalene, methyl ethyl ketone). Laboratory tests were performed under conditions of different temperature (17 to 30 oC), relative humidity (30 to 90 % RH), face velocity (0.014 to 0.41 m/s), concentration (1 to 100 parts per billion by volume [ppbv]) and sample duration (1 to 7 days). These conditions were selected to challenge the samplers across a range of conditions likely to be encountered in indoor and outdoor air field sampling programs. A second set of laboratory tests were also conducted at 1, 10 and 100 parts per million by volume (ppmv) to evaluate concentrations of interest for soil vapor monitoring using the same 10 VOCs and constant conditions (80% RH, 30 min exposure, 22 oC). Inter-laboratory testing was performed to assess the variability attributable to the differences between several laboratories used in this study. The program also included field testing of indoor air, outdoor air, sub-slab vapor and deeper soil vapor at several DoD facilities. Indoor and outdoor air samples were collected over durations of 3 to 7 days, and Summa canister samples were collected over the same durations as the passive samples for comparison. Subslab and soil vapor samples were collected with durations ranging from 10 min to 12 days, at depths of about 15 cm (immediately below floor slabs), 1.2 m and 3.7 m. Passive samplers were employed with uptake rates ranging from about 0.05 to almost 100 mL/min and analysis by both thermal desorption and solvent extraction. Mathematical modeling was performed to provide theoretical insight into the potential behavior of passive samplers in the subsurface, and to help select those with uptake rates that would minimize the risk of a negative bias from the starvation effect (which occurs when a passive sampler with a high uptake rate removes VOC vapors from the surroundings faster than they are replenished, resulting in biased concentrations). A flow-through cell apparatus was tested as an option for sampling existing sub-surface probes that are too small to accommodate a passive sampler or sampling a slip-stream of a high-velocity gas (e.g., vent-pipes of mitigation systems). The results of this demonstration show that all of the passive samplers provided data that met the performance criteria for accuracy and precision (relative percent difference less than 45 % for indoor air or 50% for soil vapor compared to conventional active samples and a coefficient of variation less than 30%) under some or most conditions. Exceptions were generally attributable to one or more of five possible causes: poor retention of analytes by the sorbent in the sampler; poor recovery of the analytes from the sorbent; starvation effects, uncertainty in the uptake rate for the specific combination of sampler/compound/conditions, or blank contamination. High (or positive) biases were less common than low biases, and attributed either to blank contamination, or to uncertainty in the uptake rates. Most of the passive samplers provided highly reproducible results throughout the demonstrations. This is encouraging because the accuracy can be established using occasional inter-method verification samples (e.g., conventional samples collected beside the passive samples for the same duration), and the field-calibrated uptake rates will be appropriate for other passive samples collected under similar conditions. Furthermore, this research demonstrated for the first time that passive samplers can be used to quantify soil vapor concentrations with accuracy and precision comparable to conventional methods. Passive samplers are generally easier to use than conventional methods (Summa canisters and active ATD tubes) and minimal training is required for most applications. A modest increase in effort is needed to select the appropriate sampler, sorbent and sample duration for the site-specific chemicals of concern and desired reporting limits compared to Summa canisters and EPA Method TO-15. As the number of samples in a given program increases, the initial cost of sampling design becomes a smaller fraction of the overall total cost, and the passive samplers gain a significant cost advantage because of the simplicity of the sampling protocols and reduced shipping charges.

Download or read book Validation of a New Soil VOC Sampler written by John F. Schabron and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil sampling and storage practices for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from samples. The En Core{reg_sign} sampler is designed to collect and store soil samples in a manner that minimizes loss of contaminants due to volatilization and/or biodegradation. An American Society for Testing and Materials (ASTM) standard practice, D 6418, Standard Practice for Using the Disposable En Core Sampler for Sampling and Storing Soil for Volatile Organic Analysis, describes use of the En Core sampler to collect and store a soil sample of approximately 5 grams or 25 grams for volatile organic analysis. To support the ASTM practice, a study was performed to estimate the precision of the performance of the 5-gram and 25-gram En Core samplers to store soil samples spiked with low concentrations of VOCs. This report discusses revision of ASTM Practice D 6418 to include information on the precision of the En Core devices and to reference an ASTM research report on the precision study. This report also discusses revision of the ASTM practice to list storage at -12 {+-} 2 C for up to 14 days and at 4 {+-} 2 C for up to 48 hours followed by storage at -12 {+-} 2C for up to 5 days as acceptable conditions for samples stored in the En Core devices. Data supporting use of these storage conditions are given in an appendix to the practice and are presented in the research report referenced for the precision study. Prior to this revision, storage in the device was specified at 4 {+-} 2 C for up to 48 hours. The En Core sampler is designed to collect soil samples for VOC analysis at the soil surface. To date, a sampling tool for collecting and storing subsurface soil samples for VOC analysis does not exist. Development of a subsurface VOC sampling/storage device was initiated in 1999. This device, which is called the Accu Core sampler, is designed so that a soil sample can be collected below the surface using a penetrometer and transported to the laboratory for analysis in the same container. During the past year, prototype devices have been tested for their performance in storing soil samples containing low concentrations of VOCs. The Accu Core sampler testing is also described in this report.

Download or read book Soil Sampling and Analysis For Volatile Organic Compounds written by United States Environmental Protect Epa and published by . This book was released on 2019-07-02 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil Sampling and Analysis For Volatile Organic Compounds

Download or read book Volatile Organic Sample Preservation for a Soil Sediment Or Waste written by RK. Dickinson and published by . This book was released on 1991 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volatile organic compounds (VOCs) are rapidly volatilized from moist soil and sediment. Losses in VOC concentrations can amount to as much as three orders of magnitude during the sampling, transportation, storage, and analytical processes. These losses usually occur during various sample handling procedures. Use of a narrow-mouth sample container such as a 40 mL volatile organic analysis (VOA) vial necessitates breaking up the soil sample, thus increasing surface area and VOC losses.

Download or read book Demonstrating the Feasibility of Polyethylene Passive Samplers for Quantitative Assessment of Volatile Organic Compounds in Soil written by Galym Saparbaiuly and published by . This book was released on 2017 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: A quantitative assessment of the nature and extent of volatile organic compounds (VOCs) in soil vapors is a valuable tool, as these chemicals are pervasive and a health concern at many contaminated sites. Motivated by the successful use of polyethylene (PE) passive samplers in sediments, this research focused on demonstrating the feasibility of PE samplers to accurately assess volatile organic compounds in soil vapors. Experimental values of PE-water partitioning coefficients (Kpew) for benzene, toluene, ethyl benzene, and ortho-xylene (BTEX) were determined. A benchtop experiment in a controlled environment was performed, which consisted of a jar of sand with known amounts of trichloroethylene (TCE) and tetrachloroethylene (PCE). The concentrations of the TCE and PCE were measured using the PE passive sampler and compared to mathematically estimated results. Finally, the PE passive samplers were tested in an actual site at the U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) and showed consistent results with the available data. The results of this thesis demonstrated that the PE passive sampling is a promising technique to measure VOCs in soil vapors.

Download or read book Contaminated Water Supplies at Camp Lejeune written by National Research Council and published by National Academies Press. This book was released on 2009-09-06 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the early 1980s, two water-supply systems on the Marine Corps Base Camp Lejeune in North Carolina were found to be contaminated with the industrial solvents trichloroethylene (TCE) and perchloroethylene (PCE). The water systems were supplied by the Tarawa Terrace and Hadnot Point watertreatment plants, which served enlisted-family housing, barracks for unmarried service personnel, base administrative offices, schools, and recreational areas. The Hadnot Point water system also served the base hospital and an industrial area and supplied water to housing on the Holcomb Boulevard water system (full-time until 1972 and periodically thereafter). This book examines what is known about the contamination of the water supplies at Camp Lejeune and whether the contamination can be linked to any adverse health outcomes in former residents and workers at the base.

Download or read book Validation of a New Soil VOC Sampler written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Soil sampling and storage practices for volatile organic analysis must be designed to minimize loss of volatile organic compounds (VOCs) from samples. The En Core{reg_sign} sampler is designed to collect and store soil samples in a manner that minimizes loss of contaminants due to volatilization and/or biodegradation. An American Society for Testing and Materials (ASTM) standard practice, D 6418, Standard Practice for Using the Disposable En Core Sampler for Sampling and Storing Soil for Volatile Organic Analysis, describes use of the En Core sampler to collect and store a soil sample of approximately 5 grams or 25 grams for volatile organic analysis. To support the ASTM practice, four studies have been performed to evaluate the performance of the En Core sampler for storage of soil samples spiked with VOCs. The first study was conducted to evaluate the performance of the device to store soil samples spiked with VOCs at high-level concentrations of approximately 2,500 [mu]g/Kg under various conditions. This analyte concentration in the soil was selected to limit the influence of the analytical method on the data. A second study was conducted to answer questions on the performance of the En Core sampler for storage of soil samples containing low-level (

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: