1、Designation: D7758 11 (Reapproved 2016)D7758 17Standard Practice forPassive Soil Gas Sampling in the Vadose Zone for SourceIdentification, Spatial Variability Assessment, Monitoring,and Vapor Intrusion Evaluations1This standard is issued under the fixed designation D7758; the number immediately foll
2、owing the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 PurposeTh
3、is practice covers standardized techniques for passively collecting soil gas samples from the vadose zone andis to be used in conjunction with Guide D5314.1.2 ObjectivesObjectives guiding the development of this practice are: (1) to synthesize and put in writing good commercialand customary practice
4、 for conducting passive soil gas sampling, (2) to ensure that the process for collecting and analyzing passivesoil gas samples is practical and reasonable, and (3) to provide standard guidance for passive soil gas sampling performed insupport of source identification, spatial variability/extent dete
5、rminations, site assessment, site monitoring, and vapor intrusioninvestigations.1.3 This practice does not address requirements of any federal, state, or local regulations or guidance or both with respect tosoil gas sampling. Users are cautioned that federal, state, and local guidance may impose spe
6、cific requirements that differ fromthose of this practice.1.4 UnitsThe values stated in SI units are to be regarded as standard. No other units of measurement are included in thisstandard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is
7、 the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.6 This practice offers a set of instructions for performing one or more specific operations. This
8、document cannot replaceeducation or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may beapplicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which theadequacy of a given profess
9、ional service must be judged, nor should this document be applied without consideration of a projectsmany unique aspects. The word “Standard” in the title means only that the document has been approved through the ASTMconsensus process.1.7 This international standard was developed in accordance with
10、 internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D
11、653 Terminology Relating to Soil, Rock, and Contained FluidsD1356 Terminology Relating to Sampling and Analysis of AtmospheresD2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD2487 Practice for Classification of Soils for Engineering Purposes (Unifi
12、ed Soil Classification System)D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and Construction1 This practice is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of S
13、ubcommittee D18.21 on Groundwater and VadoseZone Investigations.Current edition approved Oct. 1, 2016June 1, 2017. Published October 2016July 2017. Originally approved in 2011. Last previous edition approved in 20112016 asD7758D775811(2016).11. DOI: 10.1520/D7758-11R16.10.1520/D7758-17.2 For referen
14、cedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the
15、user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard
16、 as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D4597 Practice for Sampling Workplace Atmospheres to Coll
17、ect Gases or Vapors with Solid Sorbent Diffusive SamplersD5088 Practice for Decontamination of Field Equipment Used at Waste SitesD5314 Guide for Soil Gas Monitoring in the Vadose Zone (Withdrawn 2015)3D5792 Practice for Generation of Environmental Data Related to Waste Management Activities: Develo
18、pment of Data QualityObjectivesD6196 Practice for Choosing Sorbents, Sampling Parameters and Thermal Desorption Analytical Conditions for MonitoringVolatile Organic Chemicals in AirD6311 Guide for Generation of Environmental Data Related to Waste Management Activities: Selection and Optimization ofS
19、ampling DesignE2600 Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions2.2 U.S. EPA Methods4Method 8260C Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS)Method 8270C Semivolatile Organic Compounds by Gas Chromatography/Mass SpectrometryMe
20、thod TO-17 Determination of Volatile Organic Compounds in Ambient Air Using Active Sampling Onto Sorbent Tubes3. Terminology3.1 Definitions:3.1.1 For common definitions of terms in this standard, refer to Terminology D653 and D1356.3.2 Definitions of Terms Specific to This Standard:3.1.1 This sectio
21、n provides definitions and descriptions of terms used in or related to this practice. A list of acronyms and a listof symbols are also included. The terms are an integral part of this practice and are critical to an understanding of the practice andits use. Also see Terminology D653 and D1356.3.2.1
22、absorption, nthe penetration of one substance into the inner structure of another.3.1.3 active sampling, vmeans of collecting a gas-phase substance that uses a mechanical device such as a pump orvacuum-assisted critical orifice to draw air into or through a sampling device.3.2.2 adsorption, nadheren
23、ce of the atoms, ions, or molecules of a gas or liquid to the surface of another substance(chemisorption).3.2.3 ambient air, nany unconfined portion of the atmosphere; open air.3.1.6 background level, nconcentration of a substance that is typically found in ambient air (for example, as a result ofin
24、dustrial or automobile emissions), indoor air (for example, from building materials or indoor activities), or the natural geologyof an area.3.2.4 blank sample, nclean sample or a sample of matrix processed to measure artifacts in the measurement process.3.2.4.1 DiscussionBlank samples are named acco
25、rding to their type and use (for example, method blank, trip blank, field blank, and preparation ormanufacturing blank).3.1.8 contaminant, nsubstances not normally found in an environment at the observed concentration.3.2.5 desorption, nthe process of freeing from a sorbed state.3.2.6 duplicate samp
26、les, ntwo samples taken from and representative of the same population that are carried through all stepsof the sampling and analytical procedures in an identical manner.3.2.7 field blank, nclean sampling media that is carried to the sampling site, exposed to ambient air during field samplingprocedu
27、res, and transported to the laboratory for analysis (also referred to as an ambient air control sample).3.1.12 groundwater, npart of the subsurface water that is in the saturated zone.3.2.8 method blank, nquality control check to measure laboratory contamination during sample analysis.3.2.9 moisture
28、 content, nthe moisture present in a material, as determined by definite prescribed methods, expressed as apercentage of the mass of the sample on either of the following bases: (1) original mass ; (2) moisture-free (oven dried) mass (seeTest Method D2216).3.1.15 passive sampling, vmeans of collecti
29、ng a gas-phase substance that uses sorbent materials in a sampling device exposedfor a finite duration in the medium being sampled.3 The last approved version of this historical standard is referenced on www.astm.org.4 Available from United States Environmental Protection Agency (EPA), Ariel Rios Bl
30、dg., 1200 Pennsylvania Ave., NW, Washington, DC 20004, http:/www.epa.gov.D7758 1723.2.10 preparation blank, nquality control check to define the efficiency of conditioning a batch of sorbent samplers at thelaboratory for sample collection (also referred to as manufacturing blanks).3.1.17 porosity, n
31、volume fraction of rock or soil not occupied by solid material but usually occupied by liquids, vapor, or air,or combinations thereof.3.1.17.1 DiscussionPorosity is the void volume of soil or rock or both divided by the total volume of soil or rock or both.3.2.11 sampling rate, nthe ratio of mass of
32、 a given compound collected by a diffusive sampler per unit time of exposure tothe concentration of that compound in the atmosphere being sampled. The sampling rate is sometimes referred to as the uptakerate.3.1.19 saturated zone, nzone in which all of the voids in the rock or soil are filled with w
33、ater at a pressure that is greater thanatmospheric.3.1.19.1 DiscussionThe water table is the top of the saturated zone in an unconfined aquifer.3.2.12 soil gas, nvadose zone atmosphere; soil gas is the air existing in void spaces in the soil between the groundwater tableand the ground surface.3.2.13
34、 soil moisture, nwater contained in the pore spaces in the vadose zone.3.2.14 sorbent, na solid or liquid medium in or upon which materials are collected by adsorption, absorption, orchemisorption.3.2.15 sorbent sampling, vthe collection of chemicals from an air or emission sample by allowing the ai
35、r or emissions tocontact a sorbent.3.1.24 sorption, na process by which one material (the sorbent) takes up and retains another material (the sorbate) by theprocesses of adsorption or absorption.3.2.16 source, narea(s) at a site where releases have occurred that are emanating vapors from either the
36、vadose zone orgroundwater.3.2.16.1 DiscussionThere may be multiple sources at a site and the area over which any one source is defined is subject to interpretation from multipledata sets.3.2.17 spatial variability, nrelationship of organic compound mass from one location to many others at a site as
37、a functionof distance.3.2.18 starvation effect, nwhen the analyte uptake rate of a passive sorbent sampler is greater than the replenishment rate ofthe analyte around the sampler, which results in a low bias measurement.3.2.19 trip blank, nclean, unused sampling media that is carried to the sampling
38、 site and transported to the laboratory foranalysis without having been exposed to field sampling procedures.3.1.29 vadose zone, nhydrogeological region extending from the soil surface to the top of the principal water table.3.1.29.1 DiscussionPerched groundwater may exist within this zone.3.2.20 va
39、por intrusion, nmigration of a volatile chemical(s) from subsurface soil or water into an overlying or nearbybuilding.3.1.31 water table, ntop of the saturated zone in an unconfined aquifer.3.3 Acronyms:3.3.1 BLSBelow land surface (also know as below ground surface (bgs)3.2.2 COCCompound of concern3
40、.2.3 EPAEnvironmental Protection Agency3.2.4 IDIdentificationD7758 1733.2.5 MDLMethod detection limit3.3.2 QA/QCQuality assurance and quality control3.3.3 PSGPassive soil gas3.3.4 SVOCSemivolatile organic compound3.2.9 TD-GC/MSThermal desorption-gas chromato-graphy/mass spectrometry3.2.10 U.S.United
41、 States3.3.5 VOCVolatile organic compound3.3 Symbols:3.3.1 cmcentimeter3.3.2 mmeter3.3.3 mmmillimeter3.3.4 minminute3.3.5 ngmass in nanograms or 10-9 g3.3.6 sseconds3.3.7 gmass in micrograms or 10-6 g4. Summary of Practice4.1 This practice describes the passive collection and subsequent analysis of
42、soil gas samples, using sorbent samplers to trapVOCs and SVOCs in soil vapor by placing samplers in the subsurface for a period of time at multiple locations across a site.Placement of the sampler can be in open soils (i.e., (that is, not covered by a surface such as asphalt or concrete), or advance
43、dthrough slab surfaces (e.g., (for example, parking lots, streets, sidewalks, building slabs, and basement floors) to allow for subslabsoil gas sampling. This practice provides standard guidance for passive soil gas (PSG) sampling and analysis performed in supportof, but not limited to, site assessm
44、ent, site monitoring, and vapor intrusion investigations. While several different types andcombinations of sorbent materials can be used to trap VOCs and SVOCs in soil gas, this practice is intended to achieverepresentative and reproducible samples of known quality. The design of PSG surveys (for ex
45、ample, sampler design, samplespacing, the sampler exposure period, and analytical methods) is within the scope of this practice.These guidelines are not intendedto restrict the sampler design or its application in regards to spacing, sampler distribution, or time of exposure; however, theseguideline
46、s are meant to provide a general idea of common practice at the time this standard was prepared.5. Significance and Use5.1 Passive soil gas samplers are a minimally invasive, easy-to-use technique in the field for identifying VOCs and SVOCs inthe vadose zone. Similar to active soil gas and other fie
47、ld screening techniques, the simplicity and low cost of passive samplersenables them to be applied in large numbers, facilitating detailed mapping of contamination across a site, for the purpose ofidentifying source areas and release locations, focusing subsequent soil and groundwater sampling locat
48、ions, focusing remediationplans, identifying vapor intrusion pathways, tracking groundwater plumes, and monitoring remediation progress. Data generatedfrom passive soil gas sampling are semi-quantitative and are dependent on numerous factors both within and outside the controlof the sampling personn
49、el. Key variables are identified and briefly discussed in the following sections.NOTE 1Additional non-mandatory information on these factors or variables are covered in the applicable standards referenced in Section 2, and thefootnotes and Bibliography presented herewith.5.2 ApplicationThe techniques described in this practice are suitable for sampling soil gas with sorbent samplers in a widevariety of geological settings for subsequent analysis for VOCs and SVOCs. The techniques also may prove useful for speciesother
