DOCSLIB.ORG

Linear Model to Predict Soil-Gas Diffusivity from Two Soil-Water Retention Points in Unsaturated Volcanic Ash Soils

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Linear Model to Predict Soil-Gas Diffusivity from Two Soil-Water Retention Points in Unsaturated Volcanic Ash Soils SOILS AND FOUNDATIONS Vol. 48, No. 3, 397–406, June 2008 Japanese Geotechnical Society LINEAR MODEL TO PREDICT SOIL-GAS DIFFUSIVITY FROM TWO SOIL-WATER RETENTION POINTS IN UNSATURATED VOLCANIC ASH SOILS AUGUSTUS C. RESURRECCIONi),TOSHIKO KOMATSUii),KEN KAWAMOTOii), MASANOBU ODAii),SEIKO YOSHIKAWAiii) and PER MOLDRUPiv) ABSTRACT Risk assessment and design of remediation methods at soil sites polluted with gaseous phase contaminant require an accurate description of soil-gas diŠusion coe‹cient (Dp) which is typically governed by the variations in soil air-ˆlled porosity (va). For undisturbed volcanic ash soils, recent studies have shown that a linear Dp(va) model, taking into ac- count inactive air-ˆlled pore space (threshold soil-air content, va, th), captured the Dp data across the total soil moisture range from wet to completely dry conditions. In this study, we developed a simple, easy to apply, and still accurate linear Dp(va) model for undisturbed volcanic ash soils. The model slope C and intercept (interpreted as va, th) were der- X ived using the classical Buckingham (1904) Dp(va) power-law model, va ,attwosoil-watermatricpotentialsofpF2 (near ˆeld capacity condition) and pF 4.1 (near wilting point condition), and assuming the same value for the Buckin- gham exponent (X＝2.3) in agreement with measured data. This linear Dp(va) prediction model performed better than the traditionally-used non-linear Dp(va) models, especially at dry soil conditions, when tested against several indepen- dent data sets from literature. Model parameter sensitivity analysis on soil compaction eŠects showed that a decrease in slope C and va, th due to uniaxial reduction of air-ˆlled pore space in between aggregates markedly aŠects the magnitude of soil-gas diŠusivity. We recommend the new Dp(va) model using only the soil-air contents at two soil-water matric potential conditions (ˆeld capacity and wilting point) for a rapid assessment of the entire Dp-va function. Key words: air-ˆlled porosity, soil-gas diŠusion coe‹cient, soil-gas diŠusivity, soil-water retention, volcanic ash soil (IGC: D4/E14) Several predictive models for soil-gas diŠusivity, INTRODUCTION Dp/Do (where Do is the gas diŠusion coe‹cient in free 3 －3 The movement of gaseous phase contaminants in soil air), as a function of soil-air content (va,m soil-air m (e.g., volatile organic chemicals as a result of spills or soil) have been proposed. These include both empirical, leaks from underground tanks) is generally controlled by soil-type independent models and some recent and more gas diŠusion through tortuous air-ˆlled pathways in be- conceptual soil-water retention (pore-size distribution) tween soil particle-water complexes (Hers et al., 2002). dependent models. The early Dp/Do models of Buckin- An accurate prediction of the soil-gas diŠusion coe‹cient gham (1904) and Penman (1940) require only va to esti- (Dp) and its dependency on the soil moisture conditions in mate Dp, whereas the later Millington and Quirk (1960, the unsaturated zone are, therefore, essential to realisti- 1961) Dp/Do models also include the soil total porosity cally simulate the migration of soil-gaseous contaminants (F,m3 pore space m－3 soil). These soil-type independent and to quantify the associated risk from soil contamina- Dp/Do models performed poorly when tested against Dp tion(Petersenetal.,1996).Thisisespeciallythecasefor measurements on soils with diŠerent texture (including soils in urban areas where the degree of soil compaction volcanic ash soils) and across a wide interval of soil below buildings will additionally in‰uence the magnitude moisture conditions (Moldrup et al., 1999, 2000, 2003). of Dp. Since measurements of Dp are highly time consum- However, the Millington and Quirk (1961) Dp/Do model ing and require specialized measurement apparatus (Rol- is still today the most widely used model when investigat- ston and Moldrup, 2002) that is not available in most ing the diŠusion of gaseous phase contaminants in soil soils and geotechnical laboratories, a prediction model (e.g., Jury et al., 1983; H äohener and Surbeck, 2004). for Dp requiring easily obtainable input parameters To take into account the eŠect of soil type on Dp,Mol- without sacriˆcing prediction accuracy is needed. drup et al. (1996, 1999, 2000) developed the soil-water i) Dept. of Engineering Sciences, University of the Philippines-Diliman, Philippines (acresurrecci＠up.edu.ph). ii) Graduate School of Science and Engineering, Saitama University, Japan. iii) Department of Hilly Land Agriculture, National Agricultural Research Center for Western Region, Kagawa, Japan. iv) Environmental Engineering Section, Dept. of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Denmark. The manuscript for this paper was received for review on May 25, 2007; approved on February 5, 2008. Written discussions on this paper should be submitted before January 1, 2009 to the Japanese Geotechnical Society, 4-38-2, Sengoku, Bunkyo-ku, Tokyo 112-0011, Japan. Upon request the closing date may be extended one month. 397 398 RESURRECCION ET AL. characteristic (SWC)-based Dp/Do models. These SWC- MATERIALS AND METHODS based Dp/Do models performed superior to the soil-type independent models when estimating Dp for diŠerent soil Data from Literature types (Moldrup et al., 1999, 2000, 2004). For well-ag- We considered 24 Dp/Do data sets for undisturbed vol- gregated volcanic ash soils, however, the SWC-based canic ash soils from Osozawa (1998) and Resurreccion et 3 Dp/Do models had a tendency to underestimate Dp at in- al. (2007a, b) where Dp wasmeasuredon100cm core termediate soil moisture conditions (soil-water matric samples. Each undisturbed (intact) soil sample was col- potentials between pF 2 and pF 4.2; where pF＝log (－c, lected by inserting a 100-cm3 core into the soil. The soil soil-water matric potential in cm H2O)) and largely sample was removed using a hand shovel, trimmed, overestimated Dp at air- and oven-dry conditions (Mol- sealed with a vinyl tape, and stored at 2¿59Cbefore drup et al., 2003; Resurreccion et al., 2007a, b). laboratory analyses. Measurements of Dp were conducted The SWC-based Dp/Do models do not consider the at a wide range of soil moisture conditions and with a eŠect of isolated air-ˆlled pore space entrapped by inter- number of intact samples measured for Dp at air- and connected water ˆlms in between soil aggregates. This in- oven-dry conditions. Some of the data sets from Osoza- active air-ˆlled pore space governs the magnitude of Dp at wa (1998) in this study were also used by Moldrup et al. very high soil-water content, as reported by several (2003) in testing the performance of SWC-based Dp/Do authors (Call 1957; Troeh et al., 1982; Freijer, 1994). models. Resurreccion et al. (2007a, b) showed that a linear Dp/Do The undisturbed volcanic ash soils were taken from model, proposed by Moldrup et al. (2005a) and taking diŠerent locations in Japan, and are labeled according to into account the inactive pore space (threshold soil-air the sampling location (name of the local area). The data content, va, th) well captured the observed linear Dp(va)be- from Osozawa (1998) consist of 20 soils collected from havior of undisturbed, unsaturated volcanic ash soils. Tsumagoi (10 soils), Kyushu (5 soils), and Miura (5 soils). The two model parameters (slope C and intercept va, th), Measurements of Dp and soil-water retention at soil- however, have yet to be linked to measurable soil physical water matric potential intervals between pF 1 and 4.2 characteristics (e.g., soil-water retention). were conducted on triplicate samples and the mean value Alternatively, Moldrup et al. (2005b) revisited the was used in the analysis. Tsumagoi and Kyushu soils were X Buckingham (1904) power-law model (va )andsuggested characterized as humic to highly humic volcanic ash soils the possibility of linking the exponent X with soil from agricultural and grass lands, respectively; while moisture condition in terms of the soil-water matric Miura soils were characterized as light clay volcanic ash potential c or pF. Moldrup et al. (2005b) showed that X soil. Two Tsumagoi soils were also measured for Dp at is expected to vary between 2 for drier soil and gradually air-dry condition. increases to 2.5 or more for wetter soil, based on data for The remaining four volcanic ash soils are from Resur- 44 diŠerently textured undisturbed soils. In this study, we reccion et al. (2007a, b) and were sampled from Nishi- will combine the approaches of Moldrup et al. (2005a, b) Tokyo (1 soil) and Fukushima (3 soils). Nishi-Tokyo soil to arrive at a simple and easy applicable model for soil- data represent 12 intact soil samples collected along a gas diŠusivity taking into account both inactive air-ˆlled transect in a pasture ˆeld and characterized as highly or- pore space and soil-water retention. ganic loam with approximately 11z organic matter con- Volcanic ash soil diŠers from normal mineral soils be- tent, while 36 intact soil samples from Fukushima were cause this soil usually possesses dual porosity aggregated taken from a forest site at three depths (12 intact soil sam- structure including high amounts of Allophane, a clay ples per depth) with a steep organic matter gradient. Mea- mineral with a hollow particle structure. These allophanic surements of Dp and soil-water retention were done at the volcanic ash soils have unique physical and chemical soil-water matric potential intervals between pF 1 and properties, including high water retention, good 4.1. Dp was measured for 19 samples at air-dry condition drainage, and high nutrient availability that make them and for 10 samples at oven-dry condition out of the 48 suitable for agricultural production (Shoji et al., 1993).
Load more

Recommended publications
  • User''s Guide for Evaluating Subsurface Vapor Intrusion Into Buildings
    USER'S GUIDE FOR EVALUATING SUBSURFACE VAPOR INTRUSION INTO BUILDINGS Prepared By Environmental Quality Management, Inc. Cedar Terrace Office Park, Suite 250 3325 Durham-Chapel Hill Boulevard Durham, North Carolina 27707-2646 Prepared For Industrial Economics Incorporated 2667 Massachusetts Avenue Cambridge, Massachusetts 02140 EPA Contract Number: 68-W-02-33 Work Assignment No. 004 PN 030224.0002 For Submittal to Janine Dinan, Work Assignment Manager U.S. ENVIRONMENTAL PROTECTION AGENCY OFFICE OF EMERGENCY AND REMEDIAL RESPONSE ARIEL RIOS BUILDING, 5202G 1200 PENNSYLVANIA AVENUE, NW WASHINGTON, D.C. 20460 Revised February 22, 2004 DISCLAIMER This document presents technical and policy recommendations based on current understanding of the phenomenon of subsurface vapor intrusion. This guidance does not impose any requirements or obligations on the U.S. Environmental Protection Agency (EPA) or on the owner/operators of sites that may be contaminated with volatile and toxic compounds. The sources of authority and requirements for addressing subsurface vapor intrusion are the applicable and relevants statutes and regulations.. This guidance addresses the assumptions and limitations that need to be considered in the evaluation of the vapor intrusion pathway. This guidance provides instructions on the use of the vapor transport model that originally was developed by P. Johnson and R. Ettinger in 1991 and subsequently modified by EPA in 1998, 2001, and again in November 2002. On November 29, 2002 EPA published Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils (Federal Register: November 29, 2002 Volume 67, Number 230 Page 71169-71172). This document is intended to be a companion for that guidance.
    [Show full text]
  • Greenhouse Gas Fluxes from Soils of Different Land-Use Types in a Hilly
    Available online at www.sciencedirect.com Agriculture, Ecosystems and Environment 124 (2008) 125–135 www.elsevier.com/locate/agee Greenhouse gas fluxes from soils of different land-use types in a hilly area of South China Hui Liu a,b, Ping Zhao a,*, Ping Lu c, Yue-Si Wang d, Yong-Biao Lin a, Xing-Quan Rao a a South China Botanic Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China b School of Tourism and Environment, Guangdong University of Business Studies, Guangzhou 510320, PR China c EWL Sciences, P.O. Box 39443, Winnellie, Northern Territory 0821, Australia d Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, PR China Received 15 October 2006; received in revised form 3 September 2007; accepted 11 September 2007 Available online 24 October 2007 Abstract The magnitude, temporal, and spatial patterns of greenhouse gas (hereafter referred to as GHG) fluxes from soils of plantation in the subtropical area of China are still highly uncertain. To contribute towards an improvement of actual estimates, soil CO2,CH4, and N2O fluxes were measured in two different land-use types in a hilly area of South China. This study showed 2 years continuous measurements (twice a week) of GHG fluxes from soils of a pine plantation and a longan orchard system. Impacts of environmental drivers (soil temperature and soil moisture), litter exclusion and land-use (vegetation versus orchard) were presented. Our results suggested that the plantation and orchard soils were weak sinks of atmospheric CH4 and significant sources of atmospheric CO2 and N2O. Annual mean GHG fluxes from soils of plantation À1 À1 À1 À1 and orchard were: CO2 fluxes of 4.70 and 14.72 Mg CO2–C ha year ,CH4 fluxes of À2.57 and À2.61 kg CH4–C ha year ,N2O fluxes À1 À1 of 3.03 and 8.64 kg N2O–N ha year , respectively.
    [Show full text]
  • Using Respiration Quotients to Track Changing Sources of Soil Respiration Seasonally and with Experimental Warming
    Biogeosciences, 17, 3045–3055, 2020 https://doi.org/10.5194/bg-17-3045-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Using respiration quotients to track changing sources of soil respiration seasonally and with experimental warming Caitlin Hicks Pries1,2, Alon Angert3, Cristina Castanha2, Boaz Hilman3,a, and Margaret S. Torn2 1Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA 2Climate and Ecosystem Science Division, Earth and Environmental Science Area, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA 3Institute of Earth Sciences, the Hebrew University of Jerusalem, Givat Ram, Jerusalem 91904, Israel acurrently at: Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena 07745, Germany Correspondence: Caitlin Hicks Pries ([email protected]) Received: 7 June 2019 – Discussion started: 28 June 2019 Revised: 9 March 2020 – Accepted: 28 April 2020 – Published: 17 June 2020 Abstract. Developing a more mechanistic understanding of activity that may have utilized oxidized carbon substrates, soil respiration is hampered by the difficulty in determin- while growing-season values were lower in heated plots. Ex- ing the contribution of different organic substrates to respi- perimental warming and phenology change the sources of ration and in disentangling autotrophic-versus-heterotrophic soil respiration throughout the soil profile. The sensitivity of and aerobic-versus-anaerobic processes. Here, we use a rel- ARQ to these changes demonstrates its potential as a tool atively novel tool for better understanding soil respiration: for disentangling the biological sources contributing to soil the apparent respiration quotient (ARQ). The ARQ is the respiration. amount of CO2 produced in the soil divided by the amount of O2 consumed, and it changes according to which or- ganic substrates are being consumed and whether oxygen is being used as an electron acceptor.
    [Show full text]
  • An Investigation of a Soil Gas Sampling Technique and Its Applicability for Detecting Gaseous PCE and TCA Over an Unconfined Granular Aquifer
    Western Michigan University ScholarWorks at WMU Master's Theses Graduate College 6-1988 An Investigation of a Soil Gas Sampling Technique and Its Applicability for Detecting Gaseous PCE and TCA Over an Unconfined Granular Aquifer Timothy J. Mayotte Follow this and additional works at: https://scholarworks.wmich.edu/masters_theses Part of the Geology Commons, and the Hydrology Commons Recommended Citation Mayotte, Timothy J., "An Investigation of a Soil Gas Sampling Technique and Its Applicability for Detecting Gaseous PCE and TCA Over an Unconfined Granular Aquifer" (1988). Master's Theses. 1201. https://scholarworks.wmich.edu/masters_theses/1201 This Masters Thesis-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Master's Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. AN INVESTIGATION OF A SOIL GAS SAMPLING TECHNIQUE AND ITS APPLICABILITY FOR DETECTING GASEOUS PCE AND TCA OVER AN UNCONFINED GRANULAR AQUIFER by Timothy J. Mayotte A Thesis Submitted to the Faculty of The Graduate College in partial fulfillment of the requirements for the Degree of Master of Science Department of Geology Western Michigan University Kalamazoo, Michigan June 1983 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. AN INVESTIGATION OF A SOIL GAS SAMPLING TECHNIQUE AND ITS APPLICABILITY FOR DETECTING GASEOUS PCE AND TCA OVER AN UNCONFINED GRANULAR AQUIFER Timothy J. Mayotte, M.S. Western Michigan University, 1988 A soil gas sampling and analytical technique was investigated to evaluate its ability and versatility for detecting chlorinated hydrocarbons in unconfined aquifers.
    [Show full text]
  • Estimation of Soil Respiration: Techniques for Measurement of Soil Gas
    Estimation of soil respiration: Techniques for measurement of soil gas Mark Blonquist Apogee Instruments Bruce Bugbee Utah State University Scott Jones Utah State University Two methods for soil respiration measurement Soil surface flux Gradient flux (chambers): (buried sensors): • widely used • not commercially available • commercially available ($3,000-$15,000) ($15,000-60,000) • provides subsurface data • must account for altered boundary • requires diffusion coefficient layer • challenging to measure sub- • doesn’t need diffusion coefficient surface gas concentration Photo from LI-COR Biosciences Photo from Turcu et al. (2003) Respiration: CH2O + O2 CO2 + H2O 20.95% 0.04% Advantage of O2 = 20.95% = 520 x CO = 0.04% measuring CO2 2 Advantage of 1 – No bicarbonate effects measuring O2 2 – Low cost (approx. $300 vs. $900) Once physical effects are accounted for, relationship between C flux and C metabolized (respiration) is 1:1 Respiratory quotient: CO2 / O2 Carbohydrate RQ = 1.0 Protein RQ = 0.8 Fat RQ = 0.6 Lignin RQ = 0.2 Nitrification: RQ = 0.0 + NH4 + 2O2 NO3 + 2H + H2O Two ways to express gas concentration Absolute Units Relative Units • partial pressure • percent gas in air [kPa] [%] • moles of gas per unit volume • mole fraction [mol m-3] [kPa kPa-1 air] • mass of gas per unit volume • parts per million [g m-3] [ppm] Gas sensors respond to absolute concentration, but are generally calibrated to read relative units Factors affecting gas concentration in soil • Barometric Pressure Factors affecting gas concentration in soil • Barometric
    [Show full text]
  • CONTAMINATION of SOIL, SOIL GAS, and GROUND WATER by HYDROCARBON COMPOUNDS NEAR GREEAR, MORGAN COUNTY, KENTUCKY by A. Gilliam Al
    CONTAMINATION OF SOIL, SOIL GAS, AND GROUND WATER BY HYDROCARBON COMPOUNDS NEAR GREEAR, MORGAN COUNTY, KENTUCKY By A. Gilliam Alexander, Douglas D. Zettwoch, and Michael D. Unthank, U.S. Geological Survey, and Robert B. Burns, Kentucky Natural Resources and Environmental Protection Cabinet, Division of Waste Management U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 92-4138 Prepared in cooperation with the KENTUCKY NATURAL RESOURCES AND ENVIRONMENTAL PROTECTION CABINET, DIVISION OF WASTE MANAGEMENT Louisville, Kentucky 1992 U.S. DEPARTMENT OF THE INTERIOR MANUEL LUJAN, JR., Secretary U.S. Geological Survey Dallas L. Peck, Director For additional information Copies of this report can be write to: purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Books and Open-File Reports Section 2301 Bradley Avenue Federal Center, Box 25425 Louisville, KY 40217 Denver, CO 80225 CONTENTS Abstract............................................................ 1 Introduction........................................................ 1 Purpose and scope.............................................. 3 Description of the study area.................................. 3 History of ground-water contamination.......................... 4 Hydrogeologic framework............................................. 5 Alluvium....................................................... 5 Breathitt Formation............................................ 7 Lee Formation.................................................. 7 Study Approach.....................................................
    [Show full text]
  • In-Situ Measurement of Forrest Soil Gases Using Quadrupole Mass Spectrometry Timothy L
    Porter et al. Int J Earth Environ Sci 2018, 3: 149 https://doi.org/10.15344/2456-351X/2018/149 International Journal of Earth & Environmental Sciences Original Article Open Access In-Situ Measurement of Forrest Soil Gases using Quadrupole Mass Spectrometry Timothy L. Porter1* and T. Randall Dillingham2 1University of Nevada Las Vegas, Department of Physics and Astronomy, Las Vegas, NV, 89154, USA 2Northern Arizona University, Department of Physics and Astronomy, Flagstaff, AZ, 86001, USA Abstract Publication History: The net effect of forest soils on the overall atmospheric concentration of methane and carbon dioxide is Received: January 10, 2018 complex and relies upon many different factors. The flux of these gases from the soils may vary significantly Accepted: March 03, 2018 depending upon temperature, water content, soil compaction, soil composition, root structure within Published: March 05, 2018 the soil, decaying forest components within the soil, and other factors. We have developed and tested a portable, battery powered quadrupole mass spectrometer that allows for in-situ, real time measurement of Keywords: the concentration of gases in soils. This instrument allows for rapid, simultaneous quantification of methane, carbon dioxide, water vapor and other gases in the near surface region of the soils. Here, we have measured the concentrations of methane and carbon dioxide in the soils of the Coconino National Forest, comparing Carbon Dioxide, Methane, gas levels in regions of the forest that have been mechanically thinned vs. nearby regions that have been Greenhouse gas, Methane, Forest undisturbed. ecosystem Introduction region of the soils. Here, we have measured the concentrations of methane and carbon dioxide in the soils of the Coconino National Methane is a potent greenhouse gas with an effect on greenhouse Forest, comparing gas levels in regions of the forest that have been warming approximately 30 times greater than that of carbon dioxide mechanically thinned or logged vs.
    [Show full text]
  • International Soil Radiocarbon Database (Israd) Version 1.0
    Earth Syst. Sci. Data, 12, 61–76, 2020 https://doi.org/10.5194/essd-12-61-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. An open-source database for the synthesis of soil radiocarbon data: International Soil Radiocarbon Database (ISRaD) version 1.0 Corey R. Lawrence1, Jeffrey Beem-Miller2, Alison M. Hoyt2,3, Grey Monroe4, Carlos A. Sierra2, Shane Stoner2, Katherine Heckman5, Joseph C. Blankinship6, Susan E. Crow7, Gavin McNicol8, Susan Trumbore2, Paul A. Levine9, Olga Vindušková8, Katherine Todd-Brown10, Craig Rasmussen6, Caitlin E. Hicks Pries11, Christina Schädel12, Karis McFarlane13, Sebastian Doetterl14, Christine Hatté15, Yujie He9, Claire Treat16, Jennifer W. Harden7,17, Margaret S. Torn3, Cristian Estop-Aragonés18, Asmeret Asefaw Berhe19, Marco Keiluweit20, Ágatha Della Rosa Kuhnen2, Erika Marin-Spiotta21, Alain F. Plante22, Aaron Thompson23, Zheng Shi24, Joshua P. Schimel25, Lydia J. S. Vaughn3,26, Sophie F. von Fromm2, and Rota Wagai27 1US Geological Survey, Geosciences and Environmental Change Science Center, Denver, CO, USA 2Max Planck Institute for Biogeochemistry, Jena, Germany 3Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA 4Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, USA 5US Forest Service Northern Research Station, Houghton, MI, USA 6Department of Environmental Science, University of Arizona, Tucson, AZ, USA 7Department of Natural Resources and Environmental Management, University
    [Show full text]
  • Procedures for Active Soil Gas Sampling Using Direct-Push Systems FSOP 2.4.1 (March 9, 2017) Ohio EPA Division of Environmental Response and Revitalization
    Procedures for Active Soil Gas Sampling Using Direct-Push Systems FSOP 2.4.1 (March 9, 2017) Ohio EPA Division of Environmental Response and Revitalization 1.0 Scope and Applicability 1.1 Vapor intrusion is defined as vapor phase migration of volatile organic compounds (VOCs) into occupied buildings from underlying contaminated ground water and/or soil. Soil gas surveys provide information on the soil atmosphere in the vadose zone that can aid in assessing the presence, composition, source, and distribution of contaminants. The purpose of this document is to provide guidance for conducting soil gas sampling, and shall pertain to active soil gas surveys, whereby a volume of soil gas is pumped out of the vadose zone into a sample collection device for analysis. 1.2 Detection of individual constituents by active soil gas sampling is limited by the physical and chemical properties of individual contaminants of concern* and the soil characteristics of the site. In general, chemical parameters or criteria to be considered prior to selecting soil gas sampling activities are as follows: Vapor Pressure > 0.1 mm Hg Henry’s Law Constant > 0.1 Degree of soil saturation (chemical and/or water) < 80% Sampling zone is permeable and permits vapor migration Please refer to Appendix A (Chemicals of Concern for Vapor Intrusion) of the Sample Collection and Evaluation of Vapor Intrusion to Indoor Air, Guidance for Ohio EPA’S Remedial Response and Voluntary Action Programs (Ohio EPA DERR, May 2010) for a complete list of the volatile chemicals which can be detected using soil gas sampling techniques. 1.3 Results from soil gas surveys are used in both qualitative and quantitative evaluations.
    [Show full text]
  • Kowler, Andrew L. 2007. the Stable Carbon and Oxygen Isotopic Composition of Pedogenic Carbonate And
    The Stable Carbon and Oxygen Isotopic Composition of Pedogenic Carbonate and its Relationship to Climate and Ecology in Southeastern Arizona By Andrew L. Kowler December 17, 2007 ABSTRACT 18 The stable carbon (δ13C) and oxygen (δ O) isotopic composition of terrestrial carbonate has been used to reconstruct late Quaternary paleoecological and paleoclimatic conditions, respectively, for many different regions of the world. Quantitative reconstructions of past variability in climate and the distribution of C3/CAM/C4 vegetation from carbonate in soils and speleothems depend upon a rigorous examination of the modern soil isotopic system. To 18 accomplish this, we examined changes in the δ13C and δ O in relation to modern climatic and ecological conditions along an elevation gradient in southeastern Arizona. Five sites were 18 selected for study, spanning 1,170 m of elevation. Along this gradient, δ13C and δ O values from ≥50 cm soil depth range from -9.9 to -0.6‰ and from -9.4 to -1.3‰, respectively. Modeling results suggest that δ13C values were determined by soil respiration rates and the 13 proportion of C3/CAM/C4 biomass. For sites with low respiration, δ C values from >50 cm reflected an atmospheric contribution of up to 55% compared to <20% for sites with much higher respiration rates. At the lowest respiration sites, maximum observed δ18O values from >50 cm diverge from minimum (winter) predicted values by +4.3 to +7.1‰, reflecting the influence of evaporation. In contrast, values for the highest respiration rate site fell entirely between those predicted from winter and summer rainfall.
    [Show full text]
  • Vapor Intrusion Assessments Performed During Site Investigations Petroleum Remediation Program I
    www.pca.state.mn.us Vapor intrusion assessments performed during site investigations Petroleum Remediation Program I. Introduction This document describes the methodology for completing a vapor intrusion (VI) assessment at a site in the Minnesota Pollution Control Agency’s (MPCA) Petroleum Remediation Program (PRP). Vapor intrusion is the migration of volatile organic compounds (VOCs) from an underground source through soil or other pathways into buildings. A VI assessment is required when completing a site investigation within PRP. The goal of a VI assessment is to evaluate the VI pathway associated with a petroleum release. The VI pathway has three elements: receptor, vapor source, and subsurface migration route. A receptor is a person potentially affected by VI, generally an occupant of a building. A vapor source is the supply of VOCs, such as contaminated soil or groundwater or light non-aqueous phase liquids (LNAPL). A subsurface migration route is the path that vapors travel through soil or other pathways in the unsaturated zone. The VI assessment uses field-based methods to evaluate the VI pathway, including a receptor survey, soil gas sampling, sub-slab sampling, and indoor air sampling. For additional background information, see Technical Guide For Addressing Petroleum Vapor Intrusion At Leaking Underground Storage Tank Sites (EPA 2015) and Petroleum Vapor Intrusion Fundamentals of Screening, Investigation, and Management (ITRC 2014). II. Step 1 - Soil gas assessment Complete a soil gas assessment while defining the extent and magnitude of soil and groundwater impacts. There are limited situations in which the MPCA may preapprove a different scope of work than what is described here.
    [Show full text]
  • Paleoclimatic Implications of Crayfish-Mediated Prismatic Structures in Paleosols of the Paleogene Willwood Formation, Bighorn Basin, Wyoming, U.S.A
    Journal of Sedimentary Research, 2008, v. 78, 323–334 Research Article DOI: 10.2110/jsr.2008.040 PALEOCLIMATIC IMPLICATIONS OF CRAYFISH-MEDIATED PRISMATIC STRUCTURES IN PALEOSOLS OF THE PALEOGENE WILLWOOD FORMATION, BIGHORN BASIN, WYOMING, U.S.A. 1 1,2 3 3 JON J. SMITH, STEPHEN T. HASIOTIS, DANIEL T. WOODY, AND MARY J. KRAUS 1The University of Kansas, Department of Geology, Lawrence, Kansas 66045-7613, U.S.A., 2Natural History Museum and Biodiversity Research Center, Lawrence, Kansas 66045-7613, U.S.A. 3University of Colorado, Department of Geological Sciences, Boulder, Colorado 80309, U.S.A. ABSTRACT: Paleosols at Polecat Bench, northern Bighorn Basin, Wyoming, show prismatic structures not previously described in the Paleogene Willwood Formation. Prisms are densely spaced 15–50 mm diameter cylinders with vertical to slightly sinuous paths up to 400 mm long, subangular to rounded vertical faces, and slightly concave to convex tops. Prism exteriors are coated commonly by , 1-mm-thick clay films; exteriors also commonly show knobby and striated surficial morphologies. Prismatic structures are nearly exclusive to thin-bedded (, 1 m thick) compound paleosols composed of red to red-purple sandy mudrock overlying gray to green-gray heterolithic units composed chiefly of fine-grained sandstone. In addition to prismatic structures, these paleosols are characterized by large gray mottles, slickensides, and calcareous rhizocretions which crosscut or more typically follow prism exteriors. The architectural and surficial morphology of the soil prisms suggest strongly that these are pedogenically modified freshwater crayfish burrows of the ichnospecies Camborygma litonomos. At Polecat Bench, an , 40 m interval of the Willwood Formation records a transient episode of global warming known as the Paleocene–Eocene Thermal Maximum (PETM).
    [Show full text]