ASTM D6564/D6564M-17(2024)
(Guide)Standard Guide for Field Filtration of Groundwater Samples
Standard Guide for Field Filtration of Groundwater Samples
SIGNIFICANCE AND USE
4.1 A correctly designed, installed and developed groundwater monitoring well, constructed in accordance with Practice D5092/D5092M, should facilitate collection of samples of groundwater that can be analyzed to determine both the physical and chemical properties of that sample. Samples collected from these wells that require analysis for dissolved constituents should be filtered in the field prior to chemical preservation and shipment to the laboratory for analysis.
SCOPE
1.1 This guide covers methods for field filtration of groundwater samples collected from groundwater monitoring wells, excluding samples that contain non-aqueous phase liquids (either Dense Non-Aqueous Phase Liquids (DNAPLs) or Light Non-Aqueous Phase Liquids (LNAPLs)). Methods of field filtration described herein could also be applied to samples collected from wells used for other purposes. Laboratory filtration methods are not described in this guide.
1.2 This guide provides procedures available for field filtration of groundwater samples. The need for sample filtration for specific analytes should be defined prior to the sampling event and documented in the site-specific sampling and analysis plan in accordance with Guide D5903. The decision should be made on a parameter-specific basis with consideration of the data quality objectives of the sampling program, any applicable regulatory agency guidelines, and analytical method requirements.
1.3 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This guide cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This guide is not intended to represent or replace the standard of care by which the adequacy of a given professional service to be judged, nor should this guide be applied without consideration of the many unique aspects of a project. The word “Standard” in the title of this guide means only that the guide has been approved through the ASTM consensus process.
1.4 Units—The values stated in either SI Units or inch-pound units given in brackets are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D6564/D6564M − 17 (Reapproved 2024)
Standard Guide for
Field Filtration of Groundwater Samples
This standard is issued under the fixed designation D6564/D6564M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This guide covers methods for field filtration of ground-
responsibility of the user of this standard to establish appro-
water samples collected from groundwater monitoring wells,
priate safety, health, and environmental practices and deter-
excluding samples that contain non-aqueous phase liquids
mine the applicability of regulatory limitations prior to use.
(either Dense Non-Aqueous Phase Liquids (DNAPLs) or Light
1.6 This international standard was developed in accor-
Non-Aqueous Phase Liquids (LNAPLs)). Methods of field
dance with internationally recognized principles on standard-
filtration described herein could also be applied to samples
ization established in the Decision on Principles for the
collected from wells used for other purposes. Laboratory
Development of International Standards, Guides and Recom-
filtration methods are not described in this guide.
mendations issued by the World Trade Organization Technical
1.2 This guide provides procedures available for field filtra-
Barriers to Trade (TBT) Committee.
tion of groundwater samples. The need for sample filtration for
2. Referenced Documents
specific analytes should be defined prior to the sampling event
and documented in the site-specific sampling and analysis plan
2.1 ASTM Standards:
in accordance with Guide D5903. The decision should be made
D653 Terminology Relating to Soil, Rock, and Contained
on a parameter-specific basis with consideration of the data
Fluids
quality objectives of the sampling program, any applicable
D5088 Practice for Decontamination of Field Equipment
regulatory agency guidelines, and analytical method require-
Used at Waste Sites
ments.
D5092/D5092M Practice for Design and Installation of
Groundwater Monitoring Wells
1.3 This guide offers an organized collection of information
D5903 Guide for Planning and Preparing for a Groundwater
or a series of options and does not recommend a specific course
Sampling Event
of action. This guide cannot replace education or experience
D6089 Guide for Documenting a Groundwater Sampling
and should be used in conjunction with professional judgment.
Not all aspects of this guide may be applicable in all circum- Event
stances. This guide is not intended to represent or replace the
3. Terminology
standard of care by which the adequacy of a given professional
3.1 Definitions—For definitions of common technical terms
service to be judged, nor should this guide be applied without
in this standard, refer to Terminology D653.
consideration of the many unique aspects of a project. The
word “Standard” in the title of this guide means only that the
3.2 Definitions of Terms Specific to This Standard:
guide has been approved through the ASTM consensus pro-
3.2.1 filter, v—in groundwater sampling, to pass a fluid
cess.
containing particles through a filter medium whereby particles
are separated from the fluid.
1.4 Units—The values stated in either SI Units or inch-
pound units given in brackets are to be regarded separately as
3.2.2 filter, n—in groundwater sampling, a device for car-
standard. The values stated in each system may not be exact
rying out filtration which consists of the combination of the
equivalents; therefore, each system shall be used independently
filter medium and suitable hardware for constraining and
of the other. Combining values from the two systems may
supporting it in the path of the fluid.
result in non-conformance with the standard.
3.2.3 filter medium, n—in groundwater sampling, the per-
meable material used for a filter that separates particles from a
fluid passing through it.
This guide is under the jurisdiction of ASTM Committee D18 on Soil and Rock
and is the direct responsibility of Subcommittee D18.21 on Groundwater and
Vadose Zone Investigations. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Feb. 1, 2024. Published February 2024. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2000. Last previous edition approved in 2017 as D6564 – 17. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D6564_D6564M-17R24. the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6564/D6564M − 17 (2024)
3.2.4 filter system, n—in groundwater sampling, the combi- changes as they are brought from the saturated zone (where
nation of one or more filter with all the associated process groundwater is under pressure greater than atmospheric) to the
hardware required for filtration. surface (where it is under atmospheric pressure), resulting in
changes in sample chemistry. Vacuum filtration methods fur-
3.2.5 filtration, v—in groundwater sampling, the process by
ther exacerbate pressure changes. For this reason, positive
which particles are separated from a fluid by passing the fluid
pressure filtration methods are preferred. Table 1 presents
through a permeable material.
equipment options available for positive pressure and vacuum
3.2.6 filtered sample, n—in groundwater sampling, a
filtration of groundwater samples. Fig. 1 presents examples of
groundwater sample which has passed through a filter medium.
common filter characteristics and applications.
3.2.6.1 Discussion—This type of sample may also be re-
7.1.2 When selecting a filtration method, the following
ferred to as a “dissolved” sample. An unfiltered sample
criteria should be evaluated on a site-by-site basis:
containing dissolved, sorbed, coprecipitated and all suspended
7.1.2.1 Effect on sample integrity considering the potential
particles may be referred to as a “total” sample.
for the following to occur:
7.1.2.2 Sample aeration (Note 2),
4. Significance and Use
7.1.2.3 Sample agitation (Note 2),
4.1 A correctly designed, installed and developed ground-
NOTE 2—Sample aeration and increased agitation may result in sample
water monitoring well, constructed in accordance with Practice
chemical alteration.
D5092/D5092M, should facilitate collection of samples of
7.1.2.4 Change in partial pressure of sample constituents
groundwater that can be analyzed to determine both the
resulting from application of negative pressure to the sample
physical and chemical properties of that sample. Samples
during filtration,
collected from these wells that require analysis for dissolved
7.1.2.5 Sorptive losses of components from the sample onto
constituents should be filtered in the field prior to chemical
the filter medium or components of the filtration equipment
preservation and shipment to the laboratory for analysis.
(for example, flasks, filter holders and the like); and
5. Purpose of Groundwater Sample Filtration 7.1.2.6 Leaching of components from the filter medium or
components of the filtration equipment into the sample.
5.1 Groundwater samples may be filtered to separate a
7.1.2.7 Volume of sample to be filtered;
defined fraction of the sample for analysis.
7.1.2.8 Chemical compatibility of filter medium with
groundwater sample chemistry;
6. Timing of Groundwater Sample Filtration
7.1.2.9 Anticipated amount of suspended solids and the
6.1 Groundwater samples should be filtered immediately
attendant effects of particulate loading (reduction in effective
upon collection and prior to chemical preservation of the
filter pore size);
sample. Filtration should be completed in as short a time as
7.1.2.10 Time required to filter samples (Note 3);
practicable while minimizing sample aeration, agitation, pres-
sure changes, temperature changes and prolonged contact with NOTE 3—Short filtration times are recommended to minimize the time
available for chemical changes to occur in the sample.
ambient air.
7.1.2.11 Ease of use;
NOTE 1—The pressure change that occurs when the sample is brought
7.1.2.12 Availability of an appropriate medium in the de-
to the surface may cause changes in sample chemistry which include
sired filter pore size
losses of dissolved gases and precipitation of dissolved constituents such
as metals. When handling samples during filtration operations, additional
7.1.2.13 Filter surface area;
turbulence and mixing of the sample with air can cause aeration and
7.1.2.14 Use of disposable versus non-disposable equip-
oxidation of dissolved ferrous to ferric iron. Ferric iron rapidly precipi-
ment;
tates as amorphous iron hydroxide and can absorb other dissolved trace
7.1.2.15 Ease of cleaning equipment if not disposable;
metals (1) .
7.1.2.16 Potential for sample bias associated with ambient
7. Groundwater Sample Filtration Procedures air contact during sample filtration; and
7.1.2.17 Cost, evaluating the costs associated with: equip-
7.1 Preparation for Groundwater Sample Filtration—The
ment purchase price, expendable supplies and their disposal,
groundwater sample filtration process consists of three phases:
selection of filtration method; selection and pretreatment of
filter media; and groundwater sample filtration prior to transfer
into the sample container.
TABLE 1 Examples of Equipment Options for Positive and
Negative Pressure Filtration of Groundwater Samples
7.1.1 Filtration Method Selection Criteria—A wide variety
of methods are available for field filtration of groundwater Positive Pressure Filtration Equipment:
• In-line capsules
samples. In general, filtration equipment can be divided into
attached directly to a pumping device discharge hose
positive pressure filtration and vacuum (negative pressure)
attached to a pressurized transfer vessel
filtration methods, each with several different filtration medium
attached to a pressurized bailer
• Free-standing disk filter holders
configurations. Groundwater samples undergo pressure
• Syringe filters
• Zero headspace extraction vessels
Negative Pressure Filtration Equipment:
The boldface numbers given in parentheses refer to a list of references at the • Glass funnel support assembly
end of the text.
D6564/D6564M − 17 (2024)
FIG. 1 Examples of Common Filter Characteristics and Applications
time needed for filtration, time needed for decontamination of using a medium with a pore size that meets the requirements of
non-disposable equipment and quality control measures. the approved sampling and analysis plan.
7.1.2.18 The filtration method used for any given sampling
7.1.5 Preconditioning of the Filtration Medium:
program should be documented in the site-specific sampling
7.1.5.1 Filter media require preconditioning prior to sample
and analysis plan and should be consistent throughout the life
filtration (6). Purposes of filter preconditioning include: to
of the sampling program to permit comparison of data gener-
minimize positive sample bias associated with residues that
ated. If an improved method of filtration is determined to be
may exist on the filter surface or constituents that may leach
appropriate for a sampling program, the sampling and analysis
from the filter; and to create a uniform wetting front across the
plan should be revised and implemented in lieu of continuation
entire surface of the filter to prevent channel flow through the
of the existing filtration method. In this event, the effect on
filter and increase the efficiency of the filter surface area.
comparability of data needs to be examined and quantified to
Preconditioning the filter medium may not completely prevent
allow proper data analysis and interpretation (Note 4).
sorptive losses from the sample as it passes through the filter
medium.
NOTE 4—Statistical methods may need to be implemented to determine
the significance of any changes in data resulting from a change in filtration
7.1.5.2 In most cases, filter preconditioning should be done
method.
at the wellhead (Note 5) immediately prior to use. Some
7.1.3 Filtration Equipment Materials of Construction—
manufacturers prerinse filters prior to sale. These filters are
Filtration equipment and filtration media are available in a
typically marked “pre-rinsed” on filter packaging and provide
wide variety of materials of construction. Materials of con-
directions if additional field preconditioning is needed prior to
struction should be evaluated (for example, by contacting
filter use.
manufacturers, conducting leach tests or collecting equipment
NOTE 5—Some filters require preconditioning procedures that can only
blanks) to minimize sample bias:
be done in the laboratory (for example, GF/F filters are to be baked prior
7.1.3.1 Potential for negative bias due to adsorption of
to use).
constituents from the sample (1);
7.1.5.3 The procedure used to precondition the filter me-
7.1.3.2 Potential for positive bias due to desorption or
dium is determined by the following: the design of the filter
leaching of constituents into the sample (2-5);
(that is, filter capsules, or disks), the material of construction of
7.1.3.3 Reduction of the effective filter pore size caused by
the filter medium, the configuration of the filtration equipment,
clogging when filtering water containing suspended particles;
and the parameters of concern for sample analysis. Filtration
(5) and
medium manufacturers’ instructions should be followed prior
7.1.3.4 Aeration of the sample leading to precipitation of
to implementing the filter preconditioning protocols in the field
some constituents (for example, ferric hydroxide) (2).
to make sure that proper methods are employed and to
7.1.4 Selection and Pretreatment of Filter Media—Filtration
minimize potential bias of samples being filtered.
media are manufactured with specific pore size diameters
designed to permit particles of a selected size to be retained by 7.1.5.4 The volume of water used in filter preconditioning is
the filter medium. Filtration media is to be selected after dependent upon the surface area of the filter and the medium’s
considering filter pore size, and materials of construction. ability to absorb liquid. Many filter media become fragile when
Groundwater samples requiring field filtration are to be filtered saturated and
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.