1、Designation: D6564/D6564M 17Standard Guide forField Filtration of Groundwater Samples1This standard is issued under the fixed designation D6564/D6564M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This guide covers methods for field filtration of ground-water samples collected from groundwater monitoring wells,excluding samples tha
3、t contain non-aqueous phase liquids(either Dense Non-Aqueous Phase Liquids (DNAPLs) or LightNon-Aqueous Phase Liquids (LNAPLs). Methods of fieldfiltration described herein could also be applied to samplescollected from wells used for other purposes. Laboratoryfiltration methods are not described in
4、this guide.1.2 This guide provides procedures available for field filtra-tion of groundwater samples. The need for sample filtration forspecific analytes should be defined prior to the sampling eventand documented in the site-specific sampling and analysis planin accordance with Guide D5903. The dec
5、ision should be madeon a parameter-specific basis with consideration of the dataquality objectives of the sampling program, any applicableregulatory agency guidelines, and analytical method require-ments.1.3 This guide offers an organized collection of informationor a series of options and does not
6、recommend a specific courseof action. This guide cannot replace education or experienceand should be used in conjunction with professional judgment.Not all aspects of this guide may be applicable in all circum-stances. This guide is not intended to represent or replace thestandard of care by which t
7、he adequacy of a given professionalservice to be judged, nor should this guide be applied withoutconsideration of the many unique aspects of a project. Theword “Standard” in the title of this guide means only that theguide has been approved through the ASTM consensus pro-cess.1.4 UnitsThe values sta
8、ted in either SI Units or inch-pound units given in brackets are to be regarded separately asstandard. The values stated in each system may not be exactequivalents; therefore, each system shall be used independentlyof the other. Combining values from the two systems mayresult in non-conformance with
9、 the standard.1.5 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, health, and environmental practices and deter-mine the applicability of regulatory limitation
10、s prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization Techn
11、icalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD5088 Practice for Decontamination of Field EquipmentUsed at Waste SitesD5092 Practice for Design and Installation of GroundwaterMonitoring WellsD5903 Guide fo
12、r Planning and Preparing for a GroundwaterSampling EventD6089 Guide for Documenting a Groundwater SamplingEvent3. Terminology3.1 DefinitionsFor definitions of common technical termsin this standard, refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 filter, vin ground
13、water sampling, to pass a fluidcontaining particles through a filter medium whereby particlesare separated from the fluid.3.2.2 filter, nin groundwater sampling, a device for car-rying out filtration which consists of the combination of thefilter medium and suitable hardware for constraining andsupp
14、orting it in the path of the fluid.3.2.3 filter medium, nin groundwater sampling, the per-meable material used for a filter that separates particles from afluid passing through it.1This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommit
15、tee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved Dec. 15, 2017. Published January 2018. Originallyapproved in 2000. Last previous edition approved in 2012 as D6564 00 (2012)1.DOI: 10.1520/D6564_D6564M-17.2For referenced ASTM standards, visit the ASTM website, www.astm
16、.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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box
17、C700, West Conshohocken, PA 19428-2959. United StatesThis 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
18、 World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.4 filter system, nin groundwater sampling, the combi-nation of one or more filter with all the associated processhardware required for filtration.3.2.5 filtration, vin groundwater sampling, the process bywhich particles are s
19、eparated from a fluid by passing the fluidthrough a permeable material.3.2.6 filtered sample, nin groundwater sampling,agroundwater sample which has passed through a filter medium.3.2.6.1 DiscussionThis type of sample may also be re-ferred to as a “dissolved” sample. An unfiltered samplecontaining d
20、issolved, sorbed, coprecipitated and all suspendedparticles may be referred to as a “total” sample.4. Significance and Use4.1 A correctly designed, installed and developed ground-water monitoring well, constructed in accordance with PracticeD5092, should facilitate collection of samples of groundwat
21、erthat can be analyzed to determine both the physical andchemical properties of that sample. Samples collected fromthese wells that require analysis for dissolved constituentsshould be filtered in the field prior to chemical preservation andshipment to the laboratory for analysis.5. Purpose of Groun
22、dwater Sample Filtration5.1 Groundwater samples may be filtered to separate adefined fraction of the sample for analysis.6. Timing of Groundwater Sample Filtration6.1 Groundwater samples should be filtered immediatelyupon collection and prior to chemical preservation of thesample. Filtration should
23、be completed in as short a time aspracticable while minimizing sample aeration, agitation, pres-sure changes, temperature changes and prolonged contact withambient air.NOTE 1The pressure change that occurs when the sample is broughtto the surface may cause changes in sample chemistry which includelo
24、sses of dissolved gases and precipitation of dissolved constituents suchas metals. When handling samples during filtration operations, additionalturbulence and mixing of the sample with air can cause aeration andoxidation of dissolved ferrous to ferric iron. Ferric iron rapidly precipi-tates as amor
25、phous iron hydroxide and can absorb other dissolved tracemetals (1)3.7. Groundwater Sample Filtration Procedures7.1 Preparation for Groundwater Sample FiltrationThegroundwater sample filtration process consists of three phases:selection of filtration method; selection and pretreatment offilter media
26、; and groundwater sample filtration prior to transferinto the sample container.7.1.1 Filtration Method Selection CriteriaA wide varietyof methods are available for field filtration of groundwatersamples. In general, filtration equipment can be divided intopositive pressure filtration and vacuum (neg
27、ative pressure)filtration methods, each with several different filtration mediumconfigurations. Groundwater samples undergo pressurechanges as they are brought from the saturated zone (wheregroundwater is under pressure greater than atmospheric) to thesurface (where it is under atmospheric pressure)
28、, resulting inchanges in sample chemistry. Vacuum filtration methods fur-ther exacerbate pressure changes. For this reason, positivepressure filtration methods are preferred. Table 1 presentsequipment options available for positive pressure and vacuumfiltration of groundwater samples. Fig. 1 present
29、s examples ofcommon filter characteristics and applications.7.1.2 When selecting a filtration method, the followingcriteria should be evaluated on a site-by-site basis:7.1.2.1 Effect on sample integrity considering the potentialfor the following to occur:7.1.2.2 Sample aeration (Note 2),7.1.2.3 Samp
30、le agitation (Note 2),NOTE 2Sample aeration and increased agitation may result in samplechemical alteration.7.1.2.4 Change in partial pressure of sample constituentsresulting from application of negative pressure to the sampleduring filtration,7.1.2.5 Sorptive losses of components from the sample on
31、tothe filter medium or components of the filtration equipment(for example, flasks, filter holders and the like); and7.1.2.6 Leaching of components from the filter medium orcomponents of the filtration equipment into the sample.7.1.2.7 Volume of sample to be filtered;7.1.2.8 Chemical compatibility of
32、 filter medium withgroundwater sample chemistry;7.1.2.9 Anticipated amount of suspended solids and theattendant effects of particulate loading (reduction in effectivefilter pore size);7.1.2.10 Time required to filter samples (Note 3);NOTE 3Short filtration times are recommended to minimize the timea
33、vailable for chemical changes to occur in the sample.7.1.2.11 Ease of use;7.1.2.12 Availability of an appropriate medium in the de-sired filter pore size7.1.2.13 Filter surface area;7.1.2.14 Use of disposable versus non-disposable equip-ment;7.1.2.15 Ease of cleaning equipment if not disposable;7.1.
34、2.16 Potential for sample bias associated with ambientair contact during sample filtration; and7.1.2.17 Cost, evaluating the costs associated with: equip-ment purchase price, expendable supplies and their disposal,3The boldface numbers given in parentheses refer to a list of references at theend of
35、the text.TABLE 1 Examples of Equipment Options for Positive andNegative Pressure Filtration of Groundwater SamplesPositive Pressure Filtration Equipment:In-line capsulesattached directly to a pumping device discharge hoseattached to a pressurized transfer vesselattached to a pressurized bailerFree-s
36、tanding disk filter holdersSyringe filtersZero headspace extraction vesselsNegative Pressure Filtration Equipment:Glass funnel support assemblyD6564/D6564M 172time needed for filtration, time needed for decontamination ofnon-disposable equipment and quality control measures.7.1.2.18 The filtration m
37、ethod used for any given samplingprogram should be documented in the site-specific samplingand analysis plan and should be consistent throughout the lifeof the sampling program to permit comparison of data gener-ated. If an improved method of filtration is determined to beappropriate for a sampling
38、program, the sampling and analysisplan should be revised and implemented in lieu of continuationof the existing filtration method. In this event, the effect oncomparability of data needs to be examined and quantified toallow proper data analysis and interpretation (Note 4).NOTE 4Statistical methods
39、may need to be implemented to determinethe significance of any changes in data resulting from a change in filtrationmethod.7.1.3 Filtration Equipment Materials of ConstructionFiltration equipment and filtration media are available in awide variety of materials of construction. Materials of con-struc
40、tion should be evaluated (for example, by contactingmanufacturers, conducting leach tests or collecting equipmentblanks) to minimize sample bias:7.1.3.1 Potential for negative bias due to adsorption ofconstituents from the sample (1);7.1.3.2 Potential for positive bias due to desorption orleaching o
41、f constituents into the sample (2-5);7.1.3.3 Reduction of the effective filter pore size caused byclogging when filtering water containing suspended particles;(5) and7.1.3.4 Aeration of the sample leading to precipitation ofsome constituents (for example, ferric hydroxide) (2).7.1.4 Selection and Pr
42、etreatment of Filter MediaFiltrationmedia are manufactured with specific pore size diametersdesigned to permit particles of a selected size to be retained bythe filter medium. Filtration media is to be selected afterconsidering filter pore size, and materials of construction.Groundwater samples requ
43、iring field filtration are to be filteredusing a medium with a pore size that meets the requirements ofthe approved sampling and analysis plan.7.1.5 Preconditioning of the Filtration Medium:7.1.5.1 Filter media require preconditioning prior to samplefiltration (6). Purposes of filter preconditioning
44、 include: tominimize positive sample bias associated with residues thatmay exist on the filter surface or constituents that may leachfrom the filter; and to create a uniform wetting front across theentire surface of the filter to prevent channel flow through thefilter and increase the efficiency of
45、the filter surface area.Preconditioning the filter medium may not completely preventsorptive losses from the sample as it passes through the filtermedium.7.1.5.2 In most cases, filter preconditioning should be doneat the wellhead (Note 5) immediately prior to use. Somemanufacturers prerinse filters
46、prior to sale. These filters aretypically marked “pre-rinsed” on filter packaging and providedirections if additional field preconditioning is needed prior tofilter use.NOTE 5Some filters require preconditioning procedures that can onlybe done in the laboratory (for example, GF/F filters are to be b
47、aked priorto use).7.1.5.3 The procedure used to precondition the filter me-dium is determined by the following: the design of the filter(that is, filter capsules, or disks), the material of construction ofthe filter medium, the configuration of the filtration equipment,and the parameters of concern
48、for sample analysis. Filtrationmedium manufacturers instructions should be followed priorto implementing the filter preconditioning protocols in the fieldto make sure that proper methods are employed and tominimize potential bias of samples being filtered.7.1.5.4 The volume of water used in filter p
49、reconditioning isdependent upon the surface area of the filter and the mediumsability to absorb liquid. Many filter media become fragile whensaturated and are highly subject to damage during handling.FIG. 1 Examples of Common Filter Characteristics and ApplicationsD6564/D6564M 173Therefore, saturated filter media should be handled carefullyand are recommended to be preconditioned immediately priorto use.7.1.6 Preconditioning of Disk FiltersDisk filters (alsoknown as plate filters) should be preconditioned as follows:7.1.6.1 Hold the edge of the filter with f
