1、Designation: D7663 12 (Reapproved 2018)1Standard Practice forActive Soil Gas Sampling in the Vadose Zone for VaporIntrusion Evaluations1This standard is issued under the fixed designation D7663; the number immediately following the designation indicates the year oforiginal adoption or, in the case o
2、f 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.1NOTEReapproved with editorial change in February 2018.1. Scope1.1 PurposeThis practice covers standardize
3、d techniquesfor actively collecting soil gas samples from the vadose zonebeneath or near dwellings and other buildings.1.2 ObjectivesObjectives guiding the development of thispractice are: (1) to synthesize and put in writing good com-mercial and customary practice for active soil gas sampling, (2)t
4、o provide an industry standard for soil gas sampling performedin support of vapor intrusion evaluations that is practical andreasonable.1.3 This practice allows a variety of techniques to be usedfor collecting soil gas samples because different techniquesmay offer certain advantages for specific app
5、lications. Threetechniques are presented: sampling at discrete depths, samplingover a small screened interval, and sampling using permanentvapor monitoring wells.1.4 Some of the recommendations require knowledge ofpressure differential and tracer gas concentration measure-ments.1.5 The values stated
6、 in SI units shall be regarded asstandard. Other units are shown for information only.1.6 This practice does not address requirements of any local,regional, state, provincial, or national regulations or guidance,or both, with respect to soil gas sampling. Users are cautionedthat local, regional, sta
7、te, provincial, or national guidance mayimpose specific requirements that differ from those of thispractice.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety,
8、 health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.8 This practice offers a set of instructions for performingone or more specific operations. This document cannot replaceeducation or experience and should be used in conjunction withprofess
9、ional judgment. Not all aspects of this practice may beapplicable in all circumstances. This ASTM practice is notintended to represent or replace the standard of care by whichthe adequacy of a given professional service must be judged,nor should this document be applied without consideration ofa pro
10、jects many unique aspects. The word “Standard” in thetitle means only that the document has been approved throughthe ASTM consensus process.1.9 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Princ
11、iples for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD854 Test Methods for Specific Gra
12、vity of Soil Solids byWater PycnometerD1356 Terminology Relating to Sampling and Analysis ofAtmospheresD1946 Practice for Analysis of Reformed Gas by GasChromatographyD2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by MassD2487 Practice for Classification
13、of Soils for EngineeringPurposes (Unified Soil Classification System)D3404 Guide for Measuring Matric Potential in VadoseZone Using TensiometersD4696 Guide for Pore-Liquid Sampling from the Vadose1This practice is under the jurisdiction of ASTM Committee D18 on Soil andRock and is the direct respons
14、ibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved Feb. 15, 2018. Published July 2018. Originallyapproved in 2011. Last previous edition approved in 2011 as D766311. DOI:10.1520/D7663-12R18E01.2For referenced ASTM standards, visit the ASTM website, w
15、ww.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis
16、international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT
17、) Committee.1Zone (Withdrawn 2017)3D4700 Guide for Soil Sampling from the Vadose ZoneD5088 Practice for Decontamination of Field EquipmentUsed at Waste SitesD5092 Practice for Design and Installation of GroundwaterMonitoring WellsD5314 Guide for Soil Gas Monitoring in the Vadose Zone(Withdrawn 2015)
18、3D5466 Test Method for Determination of Volatile OrganicCompounds in Atmospheres (Canister Sampling Method-ology)D5504 Test Method for Determination of Sulfur Compoundsin Natural Gas and Gaseous Fuels by Gas Chromatogra-phy and ChemiluminescenceD6196 Practice for Choosing Sorbents, Sampling Param-et
19、ers and Thermal Desorption Analytical Conditions forMonitoring Volatile Organic Chemicals in AirD6725 Practice for Direct Push Installation of PrepackedScreen Monitoring Wells in Unconsolidated AquifersE741 Test Method for Determining Air Change in a SingleZone by Means of a Tracer Gas DilutionE2024
20、 Test Methods for Atmospheric Leaks Using a Ther-mal Conductivity Leak DetectorF1815 Test Methods for Saturated Hydraulic Conductivity,Water Retention, Porosity, and Bulk Density of AthleticField Rootzones3. Terminology3.1 This section provides definitions and descriptions ofterms used in or related
21、 to this practice. A list of acronyms anda list of symbols also are included. The terms are an integralpart of this practice and are critical to an understanding of thepractice and its use.3.2 Definitions:3.2.1 For definitions of common technical terms in thisstandard, refer to Terminology D653.3.3
22、Definitions of Terms Specific to This Standard:3.3.1 active sampling, na means of collecting a gas-phasesubstance that employs a mechanical device such as a pump orvacuum assisted critical orifice to draw air into or through asampling device.3.3.2 adsorption, na physical process in which moleculesor
23、 gas, of dissolved substances, or of liquids adhere in anextremely thin layer to the surfaces of solid bodies with whichthey are in contact.3.3.3 ambient air, nany unconfined portion of the atmo-sphere; open air.3.3.4 attenuation factor (), nratio of indoor air concen-tration to soil-gas concentrati
24、on for a given compound.3.3.5 background level, nthe concentration of a substancethat is typically found in ambient air (for example, due toindustrial or automobile emissions), indoor air (for example,from building materials or indoor activities) or the naturalgeology of an area.3.3.6 blank sample,
25、na sample that is intended to containnone of the analytes of interest and which is subjected to theusual analytical or measurement process to establish a zerobaseline or background value; blank samples are namedaccording to their type and use (for example, field blank, tripblank, equipment blank, re
26、agent blank).3.3.7 contaminant, nsubstances not normally found in anenvironment at the observed concentration.3.3.8 dead volume, nthe total air-filled internal volume ofthe sampling system.3.3.9 duplicate samples, ntwo samples taken from andrepresentative of the same population and carried through a
27、llsteps of the sampling and analytical procedures in an identicalmanner.3.3.10 effective porosity, nthe amount of interconnectedvoid space (within intergranular pores, fractures, openings, andthe like) available for fluid movement: generally less than totalporosity.3.3.11 equipment blank, na sample
28、of the gas which isused to purge the sampling equipment between uses; samplingequipment blanks are used to check the cleanliness of samplingdevices and the thoroughness of the cleaning procedure.3.3.12 field blank, nunused media carried to the samplingsite, exposed to sampling conditions (for exampl
29、e, connectedto the sampling lines) and returned to the laboratory and treatedas an environmental sample; field blanks are used to check foranalytical artifacts or background contaminants or both intro-duced by sampling and analytical procedures.3.3.13 fracture, na break in the mechanical continuity
30、ofa body of rock or soil caused by stress exceeding the strengthof the rock or soil. Includes joints and faults.3.3.14 free product, norganic contaminants in the liquid(“free” or non-aqueous) phase.3.3.15 ground water, nthe part of the subsurface water thatis in the saturated zone.3.3.16 liquid phas
31、e, ncontaminant residing as a liquid invadose zone pore space, often referred to as “free product.”3.3.17 moisture content, nthe amount of water lost from asoil upon drying to a constant weight, expressed as the weightper unit weight of dry soil or as the volume of water per unitbulk volume of the s
32、oil.3.3.18 passive sampling, na means of collecting an air-borne substance that depends on gaseous diffusion, gravity, orother unassisted means to bring the sample to the collectionsurface of sorbent.3.3.19 partitioning, nthe act or process of distributing achemical among different phases or compart
33、ments.3.3.20 perched aquifer, na lens of saturated soil above themain water table that forms on top of an isolated geologic layerof low permeability.3.3.21 permeability, nthe ease with which a porous me-dium can transmit a fluid under a potential gradient.3.3.22 preferential pathway, na migration ro
34、ute forchemicals of concern that has less constraint on gas transport3The last approved version of this historical standard is referenced onwww.astm.org.D7663 12 (2018)12than the surrounding soil; preferential pathways may be natural(for example, vertically fractured bedrock where the fracturesare i
35、nterconnected) or man-made (for example, utility conduits,sewers, dry wells).3.3.23 porosity, nthe volume fraction of a rock or uncon-solidated sediment not occupied by solid material but usuallyoccupied by liquids, vapor, or air, or combinations thereof.Porosity is the void volume of soil divided b
36、y the total volumeof soil.3.3.24 purge volume, nthe amount of air removed fromthe sampling system prior to the start of sample collection. Thisis usually referred to in number of dead volumes.3.3.25 reagent blank, nsample of one or more reagentsused in a given analysis.3.3.26 saturated zone, nthe zo
37、ne in which all of the voidsin the rock or soil are filled with water at a pressure that isgreater than atmospheric; the water table is the top of thesaturated zone in an unconfined aquifer.3.3.27 semi-volatile organic compound (SVOC), norganiccompounds with boiling points typically in the range 240
38、-260to 380-400 C with polar compounds in the higher range.3.3.28 soil gas, nvadose zone atmosphere. Soil gas is theair existing in void spaces in the soil between the groundwatertable and the ground surface.3.3.29 soil moisture, nthe water contained in the porespaces in the vadose zone.3.3.30 sorben
39、t sampling, nthe collection of an air samplevia removal of chemicals from a gas by passing the gas throughor allowing it to come in contact with a sorptive medium; thechemicals are subsequently desorbed for analysis.3.3.31 sub-slab vapor sampling, nthe collection of vaporfrom the zone just beneath t
40、he lowest floor slab of a building.3.3.32 tracer, na material that can be easily identified anddetermined even at very low concentrations and that may beadded to other substances to enable their movements to befollowed or their presence to be detected.3.3.33 tracer gas, na gas used with a detection
41、device todetermine the rate of air interchange within a space, or betweenspaces.3.3.34 trip blank, nclean, unused sampling media that iscarried to the sampling site and transported to the laboratoryfor analysis without having been exposed to sampling proce-dures.3.3.35 vadose zone, nhydrogeological
42、region extendingfrom the soil surface to the top of the principal water table.Perched ground water may exist within this zone.3.3.36 vapor intrusion, nthe migration of a volatilechemical(s) from subsurface soil or water into an overlying ornearby building.3.3.37 volatile organic compound (VOC), norg
43、anic com-pounds with boiling points typically ranging from a lower limitbetween 50 C and 100 C, and an upper limit between 240 Cand 260 C, where the upper limits represent mostly polarcompounds.3.3.38 water table, nthe top of the saturated zone in anunconfined aquifer.3.4 Acronyms and Abbreviations:
44、3.4.1 BLSBelow Land Surface (also known as belowground surface bgs)3.4.2 HDPEHigh density polyethylene tubing3.4.3 ODOuter Diameter3.4.4 PEEKPolyetheretherketone3.4.5 PTFEPolytetrafluoroethylene3.4.6 ppbvpart-per-billion on a volume basis3.4.7 PRTpost-run tubing3.4.8 QCQuality Control3.4.9 SVOCSemi-
45、Volatile Organic Compound3.4.10 TOToxic Organic3.4.11 USEPAUnited States Environmental ProtectionAgency3.4.12 VOCVolatile Organic Compound3.5 Symbols3.5.1 Variables (typical units)3.5.1.1 C = concentration (ppbv, g/m3,%)3.5.1.2 CDL= detection limit concentration (g/m3)3.5.1.3 d = diameter (cm)3.5.1.
46、4 L = length (cm)3.5.1.5 M = mass (g)3.5.1.6 n = number of data points3.5.1.7 Q = flow rate (cm3/min)3.5.1.8 t = time (min)3.5.1.9 V = volume (cm3)3.5.1.10 XMW= molecular weight of compound X (g/mol)3.5.1.11 = attenuation coefficient or factor (dimensionless)3.5.1.12 P = change in pressure (Pa)3.5.1
47、.13 = residence time (min)3.6 Superscripts3.6.1 = mean value3.7 Subscripts3.7.1 i = pertaining to compound, time, or location i4. Summary of Practice4.1 This practice describes the active collection of soil gassamples from soil pore spaces in the vadose zone or in fillmaterial directly under buildin
48、g slabs to determine the concen-tration of volatile organic compounds (VOCs). Three tech-niques are presented: (1) sampling at discrete depths, (2)sampling over a small screened interval, or (3) sampling usingpermanent vapor monitoring wells with one or more screenedintervals. For sampling at a give
49、n depth, options include (i) ashort stainless steel probe installed in a small diameter holedrilled through building slab, (ii) disposable drive tips andpost-run tubing (PRT), or (iii) installation of sampling pointsusing tubing placed into a borehole and sealed in place withclay or other packing material. Several different combinationsof equipment and materials can be used to actively collect soilgas samples, and this practice is intended to allow all methodsthat typically result in representative and reprodu
