ASTM D4646-16(2023)
(Test Method)Standard Test Method for 24 h Batch-Type Measurement of Contaminant Sorption by Soils and Sediments
Standard Test Method for 24 h Batch-Type Measurement of Contaminant Sorption by Soils and Sediments
SIGNIFICANCE AND USE
5.1 This test method is meant to allow for a rapid (24 h) index of a geomedia's sorption affinity for given solutes in environmental waters or leachates. A large number of samples may be run in parallel using this test method to determine a comparative ranking of those samples, based upon the amount of solute sorbed by the geomedia, or by various geomedia or leachate constituents. The 24 h time is used to make the test convenient and also to minimize microbial, light, or hydrolytic degradation which may be a problem in longer timed procedures. While Kd values are directly applicable for screening and comparative ranking purposes, their use in predictive field applications generally requires the assumption that Kd be a fixed value.
5.2 While this test method may be useful in determining 24 h Kd values for nonvolatile organic constituents, interlaboratory testing has been carried out only for the nonvolatile inorganic species arsenic and cadmium (see Section 12). However, the procedure has been tested for single-laboratory precision with polychlorinated biphenyls (PCBs) and is believed to be useful for all stable and nonvolatile inorganic and organic constituents. This test method is not considered appropriate for volatile constituents.
5.3 The 24 h time limit may be sufficient to reach a steady-state Kd; however, the calculated Kd value should be considered a non-equilibrium measurement unless steady-state has been determined. To report this determination as a steady-state Kd, this test method should be conducted for intermediate times (for example, 12, 18, and 22 h) to ensure that the soluble concentrations in the solution have reached a steady state by 24 h. If a test duration of greater than 24 h is required, refer to Test Method D4319 for an alternate procedure of longer duration.
SCOPE
1.1 This test method describes a procedure for determining the sorption affinity of waste solutes by unconsolidated geologic material in aqueous suspension. The waste solute may be derived from a variety of sources such as wells, underdrain systems, or laboratory solutions such as those produced by waste extraction tests like the Practice D3987 shake extraction method.
1.2 This test method is applicable in screening and providing relative rankings of a large number of geomedia samples for their sorption affinity in aqueous leachate/geomedia suspensions. This test method may not simulate sorption characteristics that would occur in unperturbed geologic settings.
1.3 While this procedure may be applicable to both organic and inorganic constituents, care must be taken with respect to the stability of the particular constituents and their possible losses from solution by such processes as degradation by microbes, light, hydrolysis, or sorption to material surfaces. This test method should not be used for volatile chemical constituents (see 6.1).
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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: D4646 − 16 (Reapproved 2023)
Standard Test Method for
24 h Batch-Type Measurement of Contaminant Sorption by
Soils and Sediments
This standard is issued under the fixed designation D4646; 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 2. Referenced Documents
1.1 This test method describes a procedure for determining 2.1 ASTM Standards:
the sorption affinity of waste solutes by unconsolidated geo- D1193 Specification for Reagent Water
logic material in aqueous suspension. The waste solute may be D2216 Test Methods for Laboratory Determination of Water
derived from a variety of sources such as wells, underdrain (Moisture) Content of Soil and Rock by Mass
systems, or laboratory solutions such as those produced by D3987 Practice for Shake Extraction of Solid Waste with
waste extraction tests like the Practice D3987 shake extraction Water
method. D4319 Test Method for Distribution Ratios by the Short-
Term Batch Method (Withdrawn 2007)
1.2 This test method is applicable in screening and provid-
D5681 Terminology for Waste and Waste Management
ing relative rankings of a large number of geomedia samples
E11 Specification for Woven Wire Test Sieve Cloth and Test
for their sorption affinity in aqueous leachate/geomedia sus-
Sieves
pensions. This test method may not simulate sorption charac-
E2551 Test Methods for Humidity Calibration (or Confor-
teristics that would occur in unperturbed geologic settings.
mation) of Humidity Generators for Use with Thermogra-
1.3 While this procedure may be applicable to both organic
vimetric Analyzers
and inorganic constituents, care must be taken with respect to
the stability of the particular constituents and their possible
3. Terminology
losses from solution by such processes as degradation by
3.1 Definitions:
microbes, light, hydrolysis, or sorption to material surfaces.
3.1.1 For definitions of terms used in this test method, refer
This test method should not be used for volatile chemical
to Terminology D5681.
constituents (see 6.1).
3.2 Definitions of Terms Specific to This Standard:
1.4 The values stated in SI units are to be regarded as
3.2.1 distribution coeffıcient, K —the ratio of the concentra-
d
standard. No other units of measurement are included in this
tion of solute sorbed on the soil or other geomedia divided by
standard.
its concentration in solution. A 24 h K is the analogous ratio
d
evaluated after 24 h of contact of the solute with the geomedia.
1.5 This standard does not purport to address all of the
3.2.1.1 Discussion—The dimensions of K reduce to units
safety concerns, if any, associated with its use. It is the d
of volume per mass. It is convenient to express K in units of
responsibility of the user of this standard to establish appro- d
milliliters (or cubic centimeters) of solution per gram of
priate safety, health, and environmental practices and deter-
geomedia. Dissimilar K values may be obtained if different
mine the applicability of regulatory limitations prior to use. d
initial solute concentrations are used, depending on the sorp-
1.6 This international standard was developed in accor-
tion behavior of the solute and the properties of the geomedia
dance with internationally recognized principles on standard-
(that is, nonlinear sorption curve). This concentration depen-
ization established in the Decision on Principles for the
dency may be absent where the solute concentrations are
Development of International Standards, Guides and Recom-
sufficiently low or the characteristics of the particular solute-
mendations issued by the World Trade Organization Technical
sorbent combination yield K values that are independent of the
Barriers to Trade (TBT) Committee. d
concentration of solute (that is, linear sorption curve).
1 2
This test method is under the jurisdiction of ASTM Committee D34 on Waste For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Management and is the direct responsibility of Subcommittee D34.01.04 on Waste contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Leaching Techniques. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Nov. 1, 2023. Published November 2023. Originally the ASTM website.
approved as ES 10 – 85. Last previous edition approved in 2016 as D4646 – 16. The last approved version of this historical standard is referenced on
DOI: 10.1520/D4646-16R23. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4646 − 16 (2023)
3.2.2 solute—a chemical species (for example, ion, times (for example, 12, 18, and 22 h) to ensure that the soluble
molecule, etc.) dissolved in a solution. concentrations in the solution have reached a steady state by
24 h. If a test duration of greater than 24 h is required, refer to
3.2.3 sorbate—a chemical species retained by a sorbent.
Test Method D4319 for an alternate procedure of longer
3.2.4 sorbent—a solid medium (for example, soil, sediment,
duration.
till, etc.) in or upon which solutes are collected by absorption
or adsorption.
6. Interferences
3.2.5 sorption—a physical and chemical process by which a
6.1 When dealing with solutes of unknown stability either in
sorbate is taken up or held (that is, sorbed) to a sorbent by a
contact with the geomedia or when used as blanks, care must
combination of adsorption and absorption.
be taken to determine if volatilization, hydrolysis,
3.2.6 sorption affınity—the relative degree of sorption that
photodegradation, microbial degradation, oxidation-reduction
3+ 6+
occurs between a solute and a sorbent.
(for example, Cr to Cr ), or other physicochemical pro-
cesses are operating at a significant rate within the time frame
3.2.7 unconsolidated geologic material (geomedia)—a
of the procedure. The stability and hence loss from solution
loosely aggregated solid natural material of geologic origin (for
example, soil, sediment, till, etc.). may affect the outcome of this procedure if the aforementioned
reactions are significant.
4. Summary of Test Method
6.2 Although efforts should be taken to find equipment
4.1 Distilled water, natural water, waste leachate, or other
made with contact surface materials compatible with the solute
aqueous solution containing a known concentration of a solute
solution, solute losses may occur due to sorption to material
is mixed with a known amount of unconsolidated geologic
surfaces. Thus, method blanks (that is, solutes carried through
material (geomedia) for 24 h, after which equilibrium between
the process with sorbents) should be conducted.
the sorbent and solution phase is presumed to occur. The
6.3 The compatibility of the method and the solute of
sorbent-to-solution ratio for this test is 1:20 on a mass basis.
interest may be assessed by determining the differences be-
The concentration of solute remaining in solution is measured
tween the initial solute concentration (see 9.8) and the final
and the amount of solute adsorbed is calculated by difference
method blank concentration of the solute (see 9.16). If this
with the known concentration in the initial solute. Given that
difference is greater than the expected precision of the method
the mass of solid phase is known, the distribution coefficient,
(10 %), then the K value generated may be unreliable and
d
K , for the specified experimental conditions can then be
d
must be carefully evaluated.
calculated.
5. Significance and Use 7. Apparatus
5.1 This test method is meant to allow for a rapid (24 h) 7.1 Agitation Equipment—A device of any type that rotates
index of a geomedia’s sorption affinity for given solutes in about a central axis at a rate of 29 6 2 revolutions per minute
environmental waters or leachates. A large number of samples and mixes samples in an end-over-end fashion (see Practice
may be run in parallel using this test method to determine a D3987).
comparative ranking of those samples, based upon the amount
7.2 Phase Separation Equipment—A filtration apparatus
of solute sorbed by the geomedia, or by various geomedia or
made of materials compatible with the solutions being filtered
leachate constituents. The 24 h time is used to make the test
and equipped with a 0.45 μm pore size membrane filter, or a
convenient and also to minimize microbial, light, or hydrolytic
constant-temperature centrifuge capable of separating particles
degradation which may be a problem in longer timed proce-
with diameters greater than 0.1 μm (see Section 9). If organic
dures. While K values are directly applicable for screening
d
compounds are being measured, the filtration apparatus, cen-
and comparative ranking purposes, their use in predictive field
trifuge tubes etc., should be compatible with the compounds
applications generally requires the assumption that K be a
d
being measured (for example, glass or stainless steel). Sorption
fixed value.
of solute onto the filtration membrane may be significant for
5.2 While this test method may be useful in determining some solutes, and must be evaluated by the use of blanks
through all steps of the procedure.
24 h K values for nonvolatile organic constituents, interlabo-
d
ratory testing has been carried out only for the nonvolatile
7.3 Containers—Round, wide-mouth bottles compatible
inorganic species arsenic and cadmium (see Section 12).
with the rotary extractor and of composition suitable to the
However, the procedure has been tested for single-laboratory
nature of the solute(s) under investigation and the analysis to
precision with polychlorinated biphenyls (PCBs) and is be-
be performed will be used. For nonvolatile inorganic
lieved to be useful for all stable and nonvolatile inorganic and
constituents, high-density polyethylene bottles should be used
organic constituents. This test method is not considered appro-
with the size of the bottle dictated by sample size, and the need
priate for volatile constituents.
for the solution to occupy 70 to 80 % of the container volume
5.3 The 24 h time limit may be sufficient to reach a (that is, 125, 250, or 2000 mL bottles for sample sizes of 5, 10,
steady-state K ; however, the calculated K value should be or 70 g respectively). For nonvolatile organic constituents,
d d
considered a non-equilibrium measurement unless steady-state glass bottles or stainless steel containers with watertight
has been determined. To report this determination as a steady- closures made of chemically inert materials should be used
state K , this test method should be conducted for intermediate with size requirements being the
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