ASTM D6564-00

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:D6564–00
Standard Guide for
Field Filtration of Ground-Water Samples
This standard is issued under the fixed designation D 6564; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 653 Terminology Relating to Soil, Rock, and Contained
Fluids
1.1 This guide covers methods for field filtration of ground-
D 5088 Practice for Decontamination of Field Equipment
water samples collected from ground-water monitoring wells,
Used at Non-Radioactive Waste Sites
excluding samples that contain non-aqueous phase liquids
D 5092 Practice for Design and Installation of Ground-
(either Dense Non-Aqueous Phase Liquids (DNAPLs) or Light
Water Monitoring Wells in Aquifers
Non-Aqueous Phase Liquids (LNAPLs)). Methods of field
D 5903 Guide for Planning and Preparing for a Ground-
filtration described herein could also be applied to samples
Water Sampling Event
collected from wells used for other purposes. Laboratory
D 6089 Guide for Documenting a Ground-Water Sampling
filtration methods are not described in this guide.
Event
1.2 This guide provides procedures available for field filtra-
F 740 Terminology Relating to Filtration
tion of ground-water samples. The need for sample filtration
for specific analytes should be defined prior to the sampling
3. Terminology
event and documented in the site-specific sampling and analy-
3.1 filter, v—to pass a fluid containing particles through a
sis plan in accordance with Guide D 5903.The decision should
filter medium whereby particles are separated from the fluid.
bemadeonaparameter-specificbasiswithconsiderationofthe
(F 740)
dataqualityobjectivesofthesamplingprogram,anyapplicable
3.2 filter, n—a device for carrying out filtration which
regulatory agency guidelines, and analytical method require-
consists of the combination of the filter medium and suitable
ments.
hardware for constraining and supporting it in the path of the
1.3 This guide offers an organized collection of information
fluid. (F 740)
oraseriesofoptionsanddoesnotrecommendaspecificcourse
3.3 filter medium—the permeable material used for a filter
of action. This guide cannot replace education or experience
that separates particles from a fluid passing through it.
and should be used in conjunction with professional judgment.
(F 740)
Not all aspects of this guide may be applicable in all circum-
3.4 filter preconditioning—the process of preparing a filter
stances. This guide is not intended to represent or replace the
medium for filtration
standard of care by which the adequacy of a given professional
3.5 filter system—the combination of one or more filter with
service must be judged, nor should this guide be applied
all the associated process hardware required for filtration.
without consideration of the many unique aspects of a project.
(F 740)
The word “Standard” in the title of this guide means only that
3.6 filtrate—the fluid that has passed through the filter.
the guide has been approved through the ASTM consensus
(F 740)
process.
3.7 filtration—the process by which particles are separated
1.4 This standard does not purport to address all of the
from a fluid by passing the fluid through a permeable material.
safety concerns, if any, associated with its use. It is the
(F 740)
responsibility of the user of this standard to establish appro-
3.8 filtered sample—a ground-water sample which has
priate safety and health practices and determine the applica-
passed through a filter medium.
bility of regulatory limitations prior to use.
3.8.1 Discussion—This type of sample may also be referred
2. Referenced Documents to as a “dissolved” sample. An unfiltered sample containing
dissolved, sorbed, coprecipitated and all suspended particles
2.1 ASTM Standards:
may be referred to as a “total” sample.
This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rock
and is the direct responsibility of Subcommittee D18.21 on Ground Water and Annual Book of ASTM Standards, Vol 04.08.
Vadose Zone Investigations. Annual Book of ASTM Standards, Vol 04.09.
Current edition approved June 10, 2000. Published August 2000. Annual Book of ASTM Standards, Vol 14.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6564–00
TABLE 1 Examples of Equipment Options for Positive and
3.9 particle—a small discrete mass of solid or liquid matter.
Negative Pressure Filtration of Ground Water Samples
(F 740)
Positive Pressure Filtration Equipment:
 In-line capsules
4. Significance and Use
attached directly to a pumping device discharge hose
4.1 A properly designed, installed and developed ground-
attached to a pressurized transfer vessel
attached to a pressurized bailer
water monitoring well, constructed in accordance with Practice
 Free-standing disk filter holders
D 5092, should facilitate collection of samples of ground water
 Syringe filters
that can be analyzed to determine both the physical and
 Zero headspace extraction vessels
Negative Pressure Filtration Equipment:
chemical properties of that sample. Samples collected from
 Glass funnel support assembly
these wells that require analysis for dissolved constituents
shouldbefilteredinthefieldpriortochemicalpreservationand
shipment to the laboratory for analysis.
7.1.2.1 Effect on sample integrity considering the potential
for the following to occur:
5. Purpose of Ground-Water Sample Filtration
7.1.2.2 Sample aeration (Note 2),
5.1 Ground-water samples may be filtered to separate a
7.1.2.3 Sample agitation (Note 2),
defined fraction of the sample for analysis.
NOTE 2—Sample aeration and increased agitation may result in sample
6. Timing of Ground-Water Sample Filtration
chemical alteration.
6.1 Ground-water samples should be filtered immediately
7.1.2.4 Change in partial pressure of sample constituents
upon collection and prior to chemical preservation of the
resulting from application of negative pressure to the sample
sample. (1) Filtration should be completed in as short a time
during filtration,
as possible while minimizing sample aeration, agitation, pres-
7.1.2.5 Sorptive losses of components from the sample onto
sure changes, temperature changes and prolonged contact with
the filter medium or components of the filtration equipment
ambient air.
(for example, flasks, filter holders etc.); and
7.1.2.6 Leaching of components from the filter medium or
NOTE 1—The pressure change that occurs when the sample is brought
to the surface may cause changes in sample chemistry which include
components of the filtration equipment into the sample.
losses of dissolved gases and precipitation of dissolved constituents such
7.1.2.7 Volume of sample to be filtered;
as metals. When handling samples during filtration operations, additional
7.1.2.8 Chemical compatibility of filter medium with
turbulence and mixing of the sample with air can cause aeration and
ground water sample chemistry;
oxidation of dissolved ferrous to ferric iron. Ferric iron rapidly precipi-
7.1.2.9 Anticipated amount of suspended solids and the
tates as amorphous iron hydroxide and can adsorb other dissolved trace
attendant effects of particulate loading (reduction in effective
metals (2).
filter pore size);
7. Ground-Water Sample Filtration Procedures
7.1.2.10 Time required to filter samples (Note 3);
7.1 Preparation for Ground-Water Sample Filtration—The
NOTE 3—Short filtration times are recommended to minimize the time
ground-watersamplefiltrationprocessconsistsofthreephases:
available for chemical changes to occur in the sample.
selection of filtration method; selection and pretreatment of
7.1.2.11 Ease of use;
filter media; and ground-water sample filtration prior to trans-
7.1.2.12 Availability of an appropriate medium in the de-
fer into the sample container.
sired filter pore size
7.1.1 Filtration Method Selection Criteria—A wide variety
7.1.2.13 Filter surface area;
of methods are available for field filtration of ground-water
7.1.2.14 Use of disposable versus non-disposable equip-
samples. In general, filtration equipment can be divided into
ment;
positive pressure filtration and vacuum (negative pressure)
7.1.2.15 Ease of cleaning equipment if not disposable;
filtrationmethods,eachwithseveraldifferentfiltrationmedium
7.1.2.16 Potential for sample bias associated with ambient
configurations. Ground-water samples undergo pressure
air contact during sample filtration; and
changes as they are brought from the saturated zone (where
7.1.2.17 Cost, evaluating the costs associated with: equip-
ground water is under pressure greater than atmospheric) to the
ment purchase price, expendable supplies and their disposal,
surface (where it is under atmospheric pressure), resulting in
time required for filtration, time required for decontamination
changes in sample chemistry. Vacuum filtration methods fur-
of non-disposable equipment and quality control measures.
ther exacerbate pressure changes. For this reason, positive
7.1.2.18 The filtration method used for any given sampling
pressure filtration methods are preferred. Table 1 presents
program should be documented in the site-specific sampling
equipment options available for positive pressure and vacuum
and analysis plan and should be consistent throughout the life
filtration of ground-water samples. Fig. 1 presents examples of
of the sampling program to permit comparison of data gener-
common filter characteristics and applications.
ated. If an improved method of filtration is determined to be
7.1.2 When selecting a filtration method, the following
appropriate for a sampling program, the sampling and analysis
criteria should be evaluated on a site-by-site basis:
plan should be revised and implemented in lieu of continuation
of the existing filtration method. In this event, the effect on
comparability of data needs to be examined and quantified to
The boldface numbers given in parentheses refer to a list of references at the
end of the text. allow proper data analysis and interpretation (Note 4).
D6564–00
FIG. 1 Examples of Common Filter Characteristics and Applications
NOTE 4—Statistical methods may need to be implemented to determine
7.1.5.2 In most cases, filter preconditioning should be done
thesignificanceofanychangesindataresultingfromachangeinfiltration
at the wellhead (Note 5) immediately prior to use. Some
method.
manufacturers prerinse filters prior to sale. These filters are
7.1.3 Filtration Equipment Materials of Construction—
typically marked “prerinsed” on filter packaging and provide
Filtration equipment and filtration media are available in a directions for any additional field preconditioning required
wide variety of materials of construction. Materials of con-
prior to filter use.
struction should be evaluated (e.g. by contacting manufactur-
NOTE 5—Some filters require preconditioning procedures that can only
ers, conducting leach tests or collecting equipment blanks)to
be done in the laboratory (for example, GF/F filters must be baked prior
minimize sample bias:
to use).
7.1.3.1 Potential for negative bias due to adsorption of
7.1.5.3 The procedure used to precondition the filter me-
constituents from the sample (2);
dium is determined by the following: the design of the filter
7.1.3.2 Potential for positive bias due to desorption or
(thatis,filtercapsules,ordisks),thematerialofconstructionof
leaching of constituents into the sample (3-6);
the filter medium, the configuration of the filtration equipment,
7.1.3.3 Reduction of the effective filter pore size caused by
and the parameters of concern for sample analysis. Filtration
clogging when filtering water containing suspended particles;
medium manufacturers’ instructions should be followed prior
(6) and
to implementing any filter preconditioning protocols in the
7.1.3.4 Aeration of the sample leading to precipitation of
field to ensure that proper methods are employed and to
some constituents (for example, ferric hydroxide) (3).
minimize potential bias of samples being filtered.
7.1.4 Selection and Pretreatment of Filter Media—
Filtration media are manufactured with specific pore size 7.1.5.4 The volume of water used in filter preconditioning is
dependent upon the surface area of the filter and the medium’s
diameters designed to permit particles of a selected size to be
retainedbythefiltermedium.Filtrationmediamustbeselected abilitytoabsorbliquid.Manyfiltermediabecomefragilewhen
saturated and are highly subject to damage during handling.
after considering filter pore size, and materials of construction.
Therefore, saturated filter media should be handled carefully
Ground-water samples requiring field filtration must be filtered
using a medium with a pore size that meets the requirements of and are best preconditioned immediately prior to use.
the approved sampling and analysis plan.
7.1.6 Preconditioning of Disk Filters—Disk filters (also
7.1.5 Preconditioning of the Filtration Medium:
known as plate filters) should be preconditioned as follows:
7.1.5.1 Filter media require preconditioning prior to sample
7.1.6.1 Hold the edge of the filter with filter forceps con-
filtration (7). Purposes of filter preconditioning include: to
structed of materials that are appropriate for the analytes of
minimize positive sample bias associated with residues that
interest (Note 6);
may exist on the filter surface or constituents that may leach
NOTE 6—Manufacturers often use colored parchment paper disks (for
from the filter; and to create a uniform wetting front across the
example, yellow or blue) to separate filter disks and these should not be
entire surface of the filter to prevent channel flow through the
confused with the filtration medium.
filter and increase the efficiency of the filter surface area.
Preconditioning the filter medium may not completely prevent 7.1.6.2 Saturate the entire filter disk with water (Note 7)
sorptive losses from the sample as it passes through the filter (while holding the filter over a containment vessel (not the
medium. sample bottle or filter holder) to catch all run-off, then;
D6564–00
NOTE 7—Filter manufacturers should be consulted to determine filter-
7.2.2.9 Decontaminate any equipment used for filtration of
specific volumes of water or medium-specific aqueous solution to be used
the next sample following procedures described in Practice
for optimum filter preconditioning.
D 5088.
7.1.6.3 Place the saturated filter on the appropriate filter 7.2.3 Independent Pressure Filtration Method—Ground-
stand or holder in preparation for sample filtra
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