www.epa.gov
April 2014
EPA 402-R-14-004
Revision 0
Rapid Method for Sodium Hydroxide Fusion
of Concrete and Brick Matrices Prior to
Americium, Plutonium, Strontium, Radium,
and Uranium Analyses for
Environmental Remediation Following
Radiological Incidents
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Radiation and Indoor Air
National Analytical Radiation Environmental Laboratory
Montgomery, AL 36115
Office of Research and Development
National Homeland Security Research Center
Cincinnati, OH 45268
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Revision History
Revision 0 | Original Release | 04-16-2014
This report was prepared for the National Analytical Radiation Environmental Laboratory of the Office of
Radiation and Indoor Air and the National Homeland Security Research Center of the Office of Research
and Development, United States Environmental Protection Agency. It was prepared by Environmental
Management Support, Inc., of Silver Spring, Maryland, under contract EP-W-07-037, work assignments B-
41, 1-41, and 2-43, managed by David Carman and Dan Askren. This document has been reviewed in
accordance with U.S. Environmental Protection Agency (EPA) policy and approved for publication. Note
that approval does not signify that the contents necessarily reflect the views of the Agency. Mention of trade
names, products, or services does not convey EPA approval, endorsement, or recommendation.
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices
Prior to Americium, Plutonium, Strontium, Radium, and Uranium Analyses
for Environmental Remediation Following Radiological Incidents
1. Scope and Application
1.1. The method is applicable to the sodium hydroxide fusion of concrete and brick samples,
prior to the chemical separation procedures described in the following procedures:
1.1.1. Rapid Radiochemical Method for Americium-241 in Building Materials for
Environmental Remediation Following Radiological Incidents (Reference 16.1).
1.1.2. Rapid Radiochemical Method for Plutonium-238 and Plutonium-239/240 in
Building Materials for Environmental Remediation Following Radiological
Incidents (Reference 16.2).
1.1.3. Rapid Radiochemical Method for Radium-226 in Building Materials for
Environmental Remediation Following Radiological Incidents (Reference 16.3).
1.1.4. Rapid Radiochemical Method for Total Radiostrontium (Sr-90) in Building
Materials for Environmental Remediation Following Radiological Incidents
(Reference 16.4).
1.1.5. Rapid Radiochemical Method for Isotopic Uranium in Building Materials for
Environmental Remediation Following Radiological Incidents (Reference 16.5).
1.2. This general method for concrete and brick building material applies to samples
collected following a radiological or nuclear incident. The concrete and brick samples
may be received as core samples, pieces of various sizes, dust or particles (wet or dry)
from scabbling, or powder samples.
1.3. The fusion method is rapid and rigorous, effectively digesting refractory radionuclide
particles that may be present.
1.4. Concrete or brick samples should be ground to at least 50-100 mesh size prior to fusion,
if possible.
1.5. After a homogeneous, finely ground sample is obtained, the dissolution of concrete or
brick matrices by this fusion method is expected to take approximately 1 hour per batch
of 20 samples. This method assumes the laboratory starts with a representative, finely
ground, 1-1.5-g aliquant of sample and employs simultaneous heating in multiple
furnaces. The preconcentration steps to eliminate the alkaline fusion matrix and collect
the radionuclides are expected to take approximately 1 hour.
1.6. As this method is a sample digestion and pretreatment technique, to be used prior to
other separation and analysis methods, the user should refer to those individual methods
and any project-specific requirements for the determination of applicable measurement
quality objectives (MQOs).
1.7. Application of this method by any laboratory should be validated by the laboratory using
the protocols provided in Method Validation Guide for Qualifying Methods Used by
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
Radioanalytical Laboratories Participating in Incident Response Activities (Reference
16.6), or the protocols published by a recognized standards organization for method
validation.
1.7.1. In the absence of project-specific guidance, MQOs for concrete or brick samples
may be based on the Analytical Action Levels (AALs), the Required Method
Uncertainty (WMR) and the Required Relative Method Uncertainty (cpMn) found in
the Radiological Laboratory Sample Analysis Guide for Incident Response —
Radionuclides in Soil (Reference 16.7).
2. Summary of Method
2.1. The method is based on the rapid fusion of a representative, finely ground 1-1.5 g
aliquant using rapid sodium hydroxide fusion at 600 °C.
2.2. Pu, U, and Am are separated from the alkaline matrix using an iron/titanium hydroxide
precipitation (enhanced with calcium phosphate precipitation) followed by a lanthanum
fluoride matrix removal step.
2.3. Sr is separated from the alkaline matrix using a carbonate precipitation, followed by a
calcium fluoride precipitation to remove silicates.
2.4. Ra is separated from the alkaline matrix using a carbonate precipitation.
3. Definitions, Abbreviations and Acronyms
3.1. Discrete Radioactive Particles (DRPs or "hot particles"). Paniculate matter in a sample
of any matrix where a high concentration of radioactive material is present as a tiny
particle (|im range).
3.2. Multi-Agency Radiological Analytical Laboratory Protocols (MARLAP) Manual
(Reference 16.8).
3.3. The use of the term concrete or brick throughout this method is not intended to be
limiting or prescriptive, and the method described herein refers to all concrete or
masonry related materials. In cases where the distinction is important, the specific issues
related to a particular sample type will be discussed.
4. Interferences and Limitations
NOTE: Large amounts of extraneous debris (pebbles larger than Vi", non-soil related debris) are not
generally considered to be part of a concrete or brick matrix. When consistent with data quality
objectives (DQOs), materials should be removed from the sample prior to drying. It is recommended this
step be verified with Incident Command before discarding any materials.
4.1. Concrete or brick samples with larger particle size may require a longer fusion time
during Step 11.1.8.
4.2. As much information regarding the elemental composition of the sample should be
obtained as possible. For example some concrete or brick may have native
concentrations of uranium, radium, thorium, strontium or barium, all of which may have
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Rapid Method for Sodium Hydroxide Fusion of Concrete and Brick Matrices Prior to Am, Pu, Sr, Ra, and U Analyses
an effect on the chemical separations used following the fusion of the sample. In some
cases (e.g., radium or strontium analysis), elemental analysis of the digest prior to
chemical separations may be necessary to determine native concentrations of carrier
elements present in the sample.
NOTE: In those samples where native constituents are present that could interfere with the
determination of the chemical yield (e.g., strontium for 90Sr analysis) or with the creation of a
sample test source (e.g., Ba for 226Ra analysis by alpha spectrometry), it may be necessary to
determine the concentration of these native constituents in advance of chemical separation (using a
separate aliquant of fused material) and make appropriate adjustments to the yield calculations or
amount of carrier added.
4.3. Matrix blanks for these matrices may not be practical to obtain. Efforts should be made
to obtain independent, analyte-free materials that have similar composition as the
samples to be analyzed. These blanks will serve as process monitors for the fusion, and
as potential monitors for cross contamination during batch processing.
4.4. Uncontaminated concrete or brick material may be acceptable blank material for Pu,
Am, and Sr analyses, but these materials will typically contain background levels of U
and Ra isotopes.
4.4.1. If analyte-free blank material is not available and an empty crucible is used to
generate a reagent blank sample, it is recommended that 100-125 milligram (mg)
calcium (Ca) per gram of samples be added as calcium nitrate to the empty
crucible as blank simulant. This step facilitates Sr/Ra carbonate precipitations
from the alkaline fusion matrix.
4.4.2. Tracer yields may be slightly lower for reagent blank matrices, since the concrete
and brick matrix components typically enhance recoveries across the
precipitation steps.
4.5. Samples with elevated activity or samples that require multiple analyses from a single
concrete or brick sample may need to be split after dissolution. In these cases the initial
digestate and the split fractions should be carefully measured to ensure that the sample
aliquant for analysis is accurately determined.
4.5.1. Tracer or carrier amounts (added for yield determination) may be increased
where the split allows for the normal added amount to be present in the
subsequent aliquant. For very high activity samples, the addition of the tracer or
carrier may need to be postponed until following the split, in which case special
care must be taken to ensure that the process is quantitative until isotopic
exchange with the yield monitor is achieved. This deviation from the method
should be thoroughly documented and reported in the case narrative.
4.5.2. When this method is employed and the entire volume of fused sample is
processed in the subsequent chemical separation method, the original sample size
and units are used in all calculations, with the final results reported in the units
requested by the project manager.
4.5.3. In cases where the sample digestate is split prior to analysis, the fractional
aliquant of the sample is used to determine the sample size. The calculation of
the appropriate sample size used for analysis is described in Section 12, below.
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4.6. In the preparation of blank samples, laboratory control samples (LCSs) and duplicates,
care should be taken to create these quality control (QC) samples as early in the process
as possible, and to follow the same tracer/carrier additions, digestion process, and
sample splitting used for the field samples. In the case of this method, QC samples
should be initiated at the point samples are aliquanted into crucibles for the fusion.
4.7. Although this method is applicable to a variety of subsequent chemical separation
procedures, it is not appropriate where the analysis of volatile constituents such as iodine
or polonium is required. The user of this method must ensure that analysis is not
required for any radionuclide that may be volatile under these sample preparation
conditions, prior to performing this procedure.
4.8. Zirconium crucibles used in the fusion process may be reused.
4.8.1. It is very important that the laboratory have a process for cleaning and residual
contamination assessment of the reused zirconium crucibles. The crucibles
should be cleaned very well using soap and water, followed by warm nitric acid
and then water. Blank measurements should be monitored to ensure effective
cleaning.
4.8.2. Segregation of crucibles used for low and high activity samples is recommended
to minimize the risk of cross-contamination while maximizing the efficient use
of crucibles.
4.9. Centrifuge speed of 3500 rpm is prescribed but lower rpm speeds (>2500 rpm) may be
used if 3500 rpm is not available.
4.10. Titanium chloride (TiCb) reductant is used during the co-precipitation step with iron
hydroxide for actinides to ensure tracer equilibrium and reduce uranium from U+6 to
U+4 to enhance chemical yields. This method adds 5 mL of 10 percent by mass (wt%)
along with the Fe. Adding up to 10 mL of 10 wt% TiCb may increase uranium
chemical yields, but this will need to be validated by the laboratory.
4.11. Trace levels of 226Ra may be present in Na2CC>3 used in the 226Ra pre-concentration step
used in this method. Adding less 2M Na2CC>3 (<25 mL used in this method) may reduce
996 996
Ra reagent blank levels, while still effectively pre-concentrating Ra from the
fusion matrix. This will need to be validated by the laboratory.
4. 12. La is used to pre-concentrate actinides along with LaFs in this method to eliminate
matrix interferences, including silica, which can cause column flow problems. La
follows Am in subsequent column separations and must be removed. Less La (2 mg)
was used for brick samples to minimize the chance of La interference on alpha
spectrometry peaks. While this may also be effective for concrete samples, this will
have to be validated by the laboratory.
5. Safety
5.1. General
5.1.1. Refer to your laboratory safety manual for concerns of contamination control,
personal exposure monitoring and radiation dose monitoring.
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5.1.2. Refer to your laboratory's chemical hygiene plan (or equivalent) for general
safety rules regarding chemicals in the workplace.
5.2. Radiological
5.2.1. Discrete Radioactive Particles (DRPs or "hot particles")
5.2.1.1. Hot particles will be small, on the order of 1 millimeter (mm) or less.
DRPs are typically not evenly distributed in the media and their
radiation emissions are not uniform in all directions (anisotropic).
5.2.1.2. Concrete/brick media should be individually surveyed using a thickness
of the solid sample that is appropriate for detection of the radionuclide
decay particles.
NOTE: The information regarding DRPs should accompany the samples during
processing as well as be described in the case narrative that accompanies the
sample results.
5.3. Procedure-Specific Non-Radiological Hazards:
5.3.1. The sodium hydroxide fusion is performed in a furnace at 600 °C. The operator
should exercise extreme care when using the furnace and when handling the hot
crucibles. Long tongs are recommended. Thermal protection gloves are also
recommended when performing this part of the procedure. The fusion furnace
should be used in a ventilated area (hood, trunk exhaust, etc.).
5.3.2. Particular attention should be paid to the use of hydrofluoric acid (HF). HF is an
extremely dangerous chemical used in the preparation of some of the reagents
and in the microprecipitation procedure. Appropriate personal protective
equipment (PPE) must be used in strict accordance with the laboratory safety
program specification.
6. Equipment and Supplies
6.1. Adjustable temperature laboratory hotplates.
6.2. Balance, top loading or analytical, readout display of at least ± 0.01 g.
6.3. Beakers, 100 mL, 150 mL capacity.
6.4. Centrifuge able to accommodate 225 mL tubes.
6.5. Centrifuge tubes, 50 mL and 225 mL capacity.
6.6. Crucibles, 250 mL, zirconium, with lids.
6.7. 100 uL, 200 uL, 500 uL, and 1 mL pipets or equivalent and appropriate plastic tips.
6.8. 1-10 mL electronic/manual pipet(s).
6.9. Drill with masonry bit (H-inch carbide bit recommended).
6.10. Hot water bath or dry bath equivalent.
6.11. Muffle furnace capable of reaching at least 600 °C.
6.12. Tongs for handling crucibles (small and long tongs).
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6.13. Tweezers or forceps.
6.14. Sample size reduction equipment (ball mill, paint shaker, etc.) and screens. The
necessary equipment will be based on a laboratory's specific method for the process of
producing a uniformly ground sample from which to procure an aliquant.
NOTE: See appendix for a method for ball-milling and homogenization of concrete or brick
6.15. Vortex stirrer.
7. Reagents and Standards
NOTES:
Unless otherwise indicated, all references to water should be understood to mean Type I reagent water
(ASTM D1193; Reference 16.9).
All reagents are American Chemical Society (ACS)-grade or equivalent unless otherwise specified.
7.1. Type I reagent water as defined in ASTM Standard Dl 193 (Reference 16.9).
7.2. Aluminum nitrate (A1(NO3)3' 9H2O)
7.2.1. Aluminum nitrate solution (2M): Add 750 g of aluminum nitrate (A1(NO3)3'
9H2O) to -700 mL of water and dilute to 1 L with water. Low-levels of
uranium are typically present in A1(NC>3)3 solution.
NOTE: Aluminum nitrate reagent typically contains trace levels of uranium
concentration. To achieve the lowest possible blanks for isotopic uranium measurements,
some labs have removed the trace uranium by passing ~250 mL of the 2M aluminum
nitrate reagent through ~7 mL TRU® Resin or UTEVA® Resin (Eichrom Technologies),
but this will have to be tested and validated by the laboratory.
7.3. Ammonium hydrogen phosphate (3.2M): Dissolve 106 g of (NH/^HPC^ in 200 mL of
water, heat on low to medium heat on a hot plate to dissolve and dilute to 250 mL with
water.
7.4. Boric Acid, H3BO3.
7.5. Calcium nitrate (1.25M): Dissolve 147 g of calcium nitrate tetrahydrate
(Ca(NO3)2'4H2O) in 300 mL of water and dilute to 500 mL with water.
7.6. Iron carrier (50 mg/mL): Dissolve 181 g of ferric nitrate (Fe(NC>3)3 • 9H2O) in 300 mL
water and dilute to 500 mL with water.
7.7. Hydrochloric acid (12M): Concentrated HC1, available commercially.
7.6.1. Hydrochloric acid (0.01M): Add 0.83 mL of concentrated HC1 to 800 mL of
water and dilute with water to 1 L.
7.6.2. Hydrochloric acid (1.5M): Add 125 mL of concentrated HC1 to 800 mL of
water and dilute with water to 1 L.
7.8. Hydrofluoric acid (28M): Concentrated HF, available commercially.
7.9. Lanthanum carrier (1.0 mg La3+/mL): Add 1.56 g lanthanum (III) nitrate hexahydrate
[La(NO3) 3 . 6H2O] in 300 mL water, diluted to 500 mL with water.
7.10. Nitric acid (16M): Concentrated HNOs, available commercially.
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7.10.1. Nitric acid (3M): Add 191 mL of concentrated HNO3 to 700 mL of water and
dilute to 1 L with water.
7.10.2. Nitric acid-boric acid solution (3M-0.25M): Add 15.4 g of boric acid and 190
mL of concentrated HNOs to 500 mL of water, heat to dissolve, and dilute to 1
liter with water.
7.10.3. Nitric acid (7M): Add 443 mL of concentrated HNO3 to 400 mL of water and
dilute to 1 L with water.
7.10.4. Nitric acid (8M): Add 506 mL of concentrated HNO3 to 400 mL of water and
dilute to 1 L with water.
7.11. Sodium carbonate (2M): Dissolve 212 g anhydrous Na2CC>3 in 800 mL of water, then
dilute to 1 L with water.
7.12. Sodium hydroxide pellets.
7.13. Titanium (III) chloride solution (TiCb), 10 wt% solution in 20-30 wt% hydrochloric
acid.
7.14. Radioactive tracers/carriers (used as yield monitors) and spiking solutions. A
radiotracer is a radioactive isotope of the analyte that is added to the sample to
measure any losses of the analyte. A carrier is a stable isotope form of a radionuclide
(usually the analyte) added to increase the total amount of that element so that a
measureable mass of the element is present. A carrier can be used to determine the
yield of the chemical process and/or to carry the analyte or radiotracer through the
chemical process. Refer to the chemical separation method(s) to be employed upon
completion of this dissolution technique. Tracers/carriers that are used to monitor
radiochemical/chemical yield should be added at the beginning of this procedure. This
timing allows for monitoring and correction of chemical losses in the combined
digestion process, as well as in the chemical separation method. Carriers used to
prepare sample test sources but not used for chemical yield determination (e.g., cerium
added for microprecipitation of plutonium or uranium), should be added where
indicated.
8. Sample Collection, Preservation, and Storage
Not Applicable.
9. Quality Control
9.1. Where the subsequent chemical separation technique requires the addition of carriers
and radioactive tracers for chemical yield determinations, these are to be added prior to
beginning the fusion procedure, unless there is good technical justification for doing
otherwise.
9.2. Batch quality control results shall be evaluated and meet applicable analytical protocol
specifications (APS) prior to release of unqualified data. In the absence of project-
defined APS or a project-specific quality assurance project plan (QAPP), the quality
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control sample acceptance criteria defined in the laboratory's Quality Manual and
procedures shall be used to determine acceptable performance for this method.
9.2.1. An exception to this approach may need to be taken for samples of
exceptionally high activity where human safety may be involved.
9.3. Quality control samples are generally specified in the laboratory's Quality Manual or
in a project's APS. At the very minimum the following are suggested:
9.3.1. A laboratory control sample (LCS), which consists solely of the reagents used
in this procedure and a known quantity of radionuclide spiking solution, shall
be run with each batch of samples. The concentration of the LCS should be at
or near the action level or level of interest for the project
9.3.2. One reagent blank shall be run with each batch of samples. The blank should
consist solely of the reagents used in this procedure (including tracer or carrier
from the analytical method added prior to the fusion process).
9.3.3. A sample duplicate that is equal in size to the original aliquant should be
analyzed with each batch of samples. This approach provides assurance that
the laboratory's sample size reduction and sub-sampling processes are
reproducible.
10. Calibration and Standardization
10.1. Refer to the individual chemical separation and analysis methods for calibration and
standardization protocols.
11. Procedure
11.1. Fusion
11.1.1. In accordance with the DQOs and sample processing requirements stated in
the project plan documents, remove extraneous materials from the concrete
or brick sample using a clean forceps or tweezers.
11.1.2. Weigh out a representative, finely ground 1-g aliquant of sample into a
crucible (1.5-g aliquants for 90Sr analysis).
NOTES:
It is anticipated that concrete or brick powder sample material will be dry enough to
aliquant without a preliminary drying step. In the event samples are received that
contain moisture, the samples may be dried in a drying oven at 105 °C prior to taking
the aliquant.
For Sr and Ra analyses, a reagent blank of 100-150 mg calcium per gram of sample
(prepared by evaporating 2.5 mL of 1.25M calcium nitrate, Ca(NO3)2, for radium and 3
mL of 1.25M Ca(NO3)2 for strontium) should be added to the crucible as a blank
simulant to ensure the blank behaves like the concrete or brick samples during the
precipitation steps.
11.1.3. Add the proper amount of tracer or carrier appropriate for the method being
used and the number of aliquants needed.
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11.1.4. Place crucibles on a hot plate and heat to dryness on medium heat.
NOTE: Heat on medium heat to dry quickly but not so high as to cause splattering.
11.1.5. Remove crucibles from hot plate and allow to cool.
11.1.6. Add the following amounts of sodium hydroxide based on the aliquant
size/analysis required.
1 g for Pu, Am, U: 15 g NaOH
l.SgforSr: 15 g NaOH
IgforRa: 10 g NaOH
11.1.7. Place the crucibles with lids in the 600 °C furnace using tongs.
11.1.8. Fuse samples in the crucibles for-15 minutes.
NOTE: Longer times may be needed for larger particles.
11.1.9. Remove hot crucibles from furnace very carefully using tongs, andtransfer to
hood.
11.1.10. Add -25-50 mL of water to each crucible -8 to 10 minutes (or longer) after
removing crucibles from furnace, and heat on hotplate to loosen/dissolve
solids.
11.1.11. If necessary for dissolution, add more water, and warm as needed on a
hotplate.
11.1.12. Proceed to Section 11.2 for the actinide preconcentration procedure, 11.4 for
Sr preconcentration, or 11.5 for Ra preconcentration steps.
11.2. Preconcentration of Actinides (Pu, U, or Am) from Hydroxide Matrix
11.2.1. Pipet 2.5 mL of iron carrier (50 mg/mL) into a labeled 225-mL centrifuge
tube for each sample.
11.2.2. Add La carrier to each 225-mL tube as follows:
Concrete: 5 mL 1 mg La/mL for Pu, Am, U
Brick: 5 mL 1 mg La/mL for Pu, and U; 2 mL 1 mg La/mL for Am
11.2.3. Transfer each fused sample to a 225 mL centrifuge tube, rinse crucibles well
with water, and transfer rinses to each tube.
11.2.4. Dilute each sample to approximately 180 mL with water.
11.2.5. Cool the 225 mL centrifuge tubes in an ice bath to approximately room
temperature as needed.
11.2.6. Pipet 1.25M Ca(NO3) 2 and 3.2M (NH4)2HPO4 into each tube as follows:
Pu, Am: 2 mL 1.25M Ca(NO3) 2 and 3 mL 3.2M (NH4)2HPO4
U: 3 mL 1.25M Ca(NO3)2 and 5 mL 3.2M (NH4)2HPO4
11.2.7. Cap tubes and mix well.
11.2.8. Pipet 5 mL of 10 wt% TiCb into each tube, and cap and mix immediately.
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11.2.9. Cool 225 mL centrifuge tubes in an ice bath for -10 minutes.
11.2.10. Centrifuge tubes for 6 minutes at 3500 rpm.
11.2.11. Pour off the supernate, and discard to waste.
11.2.12. Add 1.5M HC1 to each tube to redissolve each sample in a total volume of
-60 mL.
11.2.13. Cap and shake each tube to dissolve solids as well as possible.
NOTE: There will typically be undissolved solids, which is acceptable.
11.2.14. Dilute each tube to -170 mL with 0.01M HC1. Cap and mix.
11.2.15. Pipet 1 mL of 1.0 mg La/mL into each tube.
11.2.16. Pipet 3 mL of 10 wt% TiCb into each tube. Cap and mix.
11.2.17. Add 22 mL of concentrated HF into each tube. Cap and mix well.
11.2.18. Place tubes to set in an ice bath for-10 minutes to get the tubes very cold.
11.2.19. Centrifuge for-10 minutes at 3000 rpm or more or as needed.
11.2.20. Pour off supernate, and discard to waste.
11.2.21. Pipet 5 mL of 3M HNCh - 0.25M boric acid into each tube.
11.2.22. Cap, mix and transfer contents of the tube into a labeled 50 mL centrifuge
tube.
11.2.23. Pipet 6 mL of 7M HNOs and 7 mL of 2M aluminum nitrate into each tube,
cap and mix (shake or use a vortex stirrer), and transfer rinse to 50-mL
centrifuge tube.
11.2.24. Pipet 3 ml of 3M HNO3 directly into the 50 mL centrifuge tube.
11.2.25. Warm each 50 mL centrifuge tube in a hot water bath for a few minutes,
swirling to dissolve.
11.2.26. Remove each 50 mL centrifuge tube from the water bath and allow to cool to
room temperature
11.2.27. Centrifuge the 50 ml tubes at 3500 rpm for 5 minutes to remove any traces of
solids (may not be visible prior to centrifuging), and transfer solutions to
labeled beakers or tubes for further processing. Discard any solids.
11.2.28. Proceed directly to any of those methods listed in Sections 1.1.1, 1.1.2, or
1.1.5(forPu, U, or Am).
11.3. Preconcentration of 90Sr from Hydroxide Matrix (Concrete)
NOTE: The preconcentration steps for 90Sr in this section can also be applied to brick samples, but
this will have to be validated by the laboratory. See Section 11.4 for steps validated for 90Sr in
brick samples.
11.3.1. Transfer each fused sample to a 225-mL centrifuge tube, rinse crucibles well
with water, and transfer rinses to each tube.
11.3.2. Dilute to approximately 150 mL with water.
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11.3.3. Add 15-mL concentrated HC1 to each tube.
11.3.4. Cap and mix solution in each tube.
11.3.5. Pipet 1-mL 1.25M Ca(NO3)2into each tube.
11.3.6. Add 2-mL 50-mg/mL iron carrier into each tube.
11.3.7. Add 25-mL 2MNa2CO3to each tube.
11.3.8. Cap tubes and mix well.
11.3.9. Cool 225-mL centrifuge tubes in an ice bath for -10 minutes.
11.3.10. Centrifuge tubes for 5 minutes at 3500 rpm.
11.3.11. Pour off the supernate, and discard to waste.
11.3.12. Add 1.5MHC1 to each tube to redissolve each sample in a total volume of
-50 mL.
11.3.13. Cap and shake each tube to dissolve solids as well as possible.
11.3.14. Dilute each tube to -170 mL with 0.01M HC1. Cap and mix.
11.3.15. Add 22 mL of concentrated HF into each tube. Cap and mix well.
11.3.16. Place tubes to set in an ice bath for-10 minutes to get the tubes very cold.
11.3.17. Centrifuge for-6 minutes at 3500 rpm.
11.3.18. Pour off supernate, and discard to waste.
11.3.19. Pipet 5 mL of concentrated HNO3and 5 mL of 3M HNO3 - 0.25M boric acid
into each 225 mL tube to dissolve precipitate.
11.3.20. Cap and mix well. Transfer contents of the tube into a labeled 50-mL
centrifuge tube.
11.3.21. Pipet 5 mL of 3M HNOs and 5 mL of 2M aluminum nitrate into each tube,
cap tube and mix.
11.3.22. Transfer rinse solutions to 50-mL centrifuge tubes and mix well (shake or use
vortex stirrer).
11.3.23. Centrifuge the 50 mL tubes at 3500 rpm for 5 minutes to remove any traces
of solids.
11.3.24. Transfer solutions to labeled beakers or new 50 mL tubes for further
processing.
11.3.25. If solids remain, add 5 mL 3M HNO3to each tube, cap, and mix well,
centrifuge for 5 minutes and add the supernate to the sample solution.
Discard any residual solids.
11.3.26. Set aside for 90Sr analysis using RapidRadiochemicalMethodfor Total
Radiostrontium (Sr-90) In Building Materials for Environmental
Remediation Following Radiological Incidents (Reference 16.4).
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11.4. Preconcentration of 90Sr from Hydroxide Matrix (Brick)
NOTE: The preconcentration steps for 90Sr in this section, using calcium phosphate instead of
calcium carbonate, can also be applied to concrete samples but this will have to be validated by
the laboratory. See Section 11.3 for steps validated for 90Sr in concrete samples.
11.4.1. Transfer each fused sample to a 225-mL centrifuge tube, rinse crucibles well
with water, and transfer rinses to each tube.
11.4.2. Dilute to approximately 150 mL with water.
11.4.3. Pipet2mL 1.25M Ca(NO3)2 into each tube.
11.4.4. Add 1 mL 50-mg/mL iron carrier into each tube.
11.4.5. Add 5 mL 3.2M (NH4)2HPO4to each tube.
11.4.6. Cap tubes and mix well.
11.4.7. Centrifuge tubes for 5 minutes at 3500 rpm.
11.4.8. Pour off the supernate and discard to waste.
11.4.9. Add 1.5M HC1 to each tube to redissolve each sample in a total volume of
-60 mL.
11.4.10. Cap and shake each tube to dissolve solids as well as possible.
11.4.11. Dilute each tube to -170 mL with 0.01M HC1. Cap and mix.
11.4.12. Add 22 mL of concentrated HF into each tube. Cap and mix well.
11.4.13. Place tubes to set in an ice bath for-10 minutes to get the tubes very cold.
11.4.14. Centrifuge for-6 minutes at 3500 rpm.
11.4.15. Pour off supernate and discard to waste.
11.4.16. Pipet 5 mL of concentrated HNO3 and 5 mL of 3M HNO3 - 0.25M boric acid
into each 225 mL tube to dissolve precipitate.
11.4.17. Cap and mix well. Transfer contents of the tube into a labeled 50-mL
centrifuge tube.
11.4.18. Pipet 5 mL of 3M HNOs and 5 mL of 2M aluminum nitrate into each tube,
cap tube and mix.
11.4.19. Transfer rinse solutions to 50 mL centrifuge tubes and mix well (shake or use
vortex stirrer).
11.4.20. Centrifuge the 50 mL tubes at 3500 rpm for 5 minutes to remove any traces
of solids.
11.4.21. Transfer solutions to labeled beakers or new 50 mL tubes for further
processing.
11.4.22. If solids remain, add 5 mL 3M HNO3 to each tube, cap and mix well,
centrifuge for 5 minutes and add the supernate to the sample solution.
Discard any residual solids.
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11.4.23. Set aside for 90Sr analysis using RapidRadiochemicalMethodfor Total
Radiostrontium (Sr-90) In Building Materials for Environmental
Remediation Following Radiological Incidents (Reference 16.4).
99^
11.5. Preconcentration of Ra from Hydroxide Matrix
11.5.1. Transfer each sample to a 225 mL centrifuge tube, rinse crucibles well with
water, and transfer rinses to each tube.
11.5.2. Dilute to approximately 150 mL with water.
11.5.3. Add 10 mL of concentrated HC1 to each tube.
11.5.4. Cap and mix each tube well.
11.5.5. Pipet 0.5 mL of 1.25M Ca(NO3)2into each tube.
11.5.6. Add 25 mL of 2M Na2CO3 to each tube.
11.5.7. Cap tubes and mix.
11.5.8. Cool 225-mL centrifuge tubes in an ice bath for ~ 5-10 minutes.
11.5.9. Centrifuge tubes for 6 minutes at 3500 rpm.
11.5.10. Pour off the supernate, and discard to waste.
11.5.11. Pipet 10 mL 1.5M HC1 into each tube to dissolve precipitate. Cap and mix.
11.5.12. Transfer sample solution to a 50-mL centrifuge tube.
11.5.13. Pipet lOmL 1.5MHC1 into each 225-mL tube to rinse. Cap and rinse well.
11.5.14. Transfer rinse solution to 50 mL-tube and mix well.
NOTE: Typically the HC1 added to dissolve the carbonate precipitate is sufficient to
acidify the sample. If the precipitate was unusually large and milky suspended solids
remain, indicating additional acid is needed, the pH can be checked to verify it is pH 1
or less. To acidify the pH <1,1 or 2 mL of concentrated hydrochloric acid may be added
to acidify the solution further and get it to clear. Undissolved solids may be more likely
to occur with brick samples. Tubes may be warmed in a water bath to help dissolve
samples.
11.5.15. If solids remain, add 5 mL 1.5MHC1 to each tube, cap and mix well,
centrifuge for 5 minutes and add the supernate to the sample solution.
Discard any residual solids.
99^
11.5.16. Set aside for Ra analysis using Rapid Radiochemical Method for Radium-
226 in Building Materials for Environmental Remediation Following
Radiological Incidents (Reference 16.3).
12. Data Analysis and Calculations
12.1. Equations for determination of final result, combined standard uncertainty, and
radiochemical yield (if required) are found in the corresponding chemical separation
and analysis methods, with the units being provided by the project manager.
12.2. In cases where samples have elevated activity, smaller initial sample aliquants may be
taken from the original sample. Alternately, smaller aliquant volumes may be taken
from the final sample volume containing the dissolved precipitate (digestate).
Aliquants should be removed carefully and accurately from this final sample volume.
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NOTE: Small aliquants taken from the final sample digestate for Sr and Ra analysis may be used
in the respective analytical procedures as is. Smaller aliquants for actinide analysis should be
diluted to a 15 mL total volume with 3M HNO3 so that load solution acidity is maintained when
valence adjustment reagents are added.
For a single split, the effective size of sample is calculated:
w =w —±- (i\
a s j~\ \ /
s
Where:
Ws = original sample size, in the units designated by the project manager (e.g.,
1 g, etc.)
Ds = mass or volume of the entire final digestate, (e.g., 20 mL, etc.).
Da = mass or volume of the aliquant of digestate used for the individual
analyses, (e.g., 5.0 mL, etc.). Note that the values for Da must be in the
same units used in Ds.
Wa = sample aliquant size, used for analysis, in the units designated by the
project manager (e.g., kg, g, etc.).
NOTE: For higher activity samples, additional dilution may be needed. In such cases, Equation 1
should be modified to reflect the number of splits and dilutions performed. It is also important to
measure the masses or volumes, used for aliquanting or dilution, to enough significant figures so
that their uncertainties have an insignificant impact on the final uncertainty budget. In cases
where the sample will not be split prior to analysis, the sample aliquant size is simply equal to the
original sample size, in the same units requested by the project manager.
13. Method Performance
13.1. Method validation results are to be reported.
13.2. The method performance data for the analysis of concrete and brick by this dissolution
method may be found in the attached appendices.
13.3. Expected turnaround time per sample
13.3.1. For a representative, finely ground 1 -g aliquant of sample, the fusion should
add approximately 2 hours per batch to the time specified in the individual
chemical separation methods.
13.3.2. The preconcentration steps should add approximately 2 to 2.5 hours per
batch.
NOTE : Processing times for the subsequent chemical separation methods are given in
those methods for batch preparations.
14. Pollution Prevention
This method inherently produces no significant pollutants. The sample and fusion reagents
are retained in the final product and are carried into the ensuing chemical separation
techniques, which marginally increases the salt content of the effluent waste. It is noted that
if the sampled particulates include radionuclides which may be volatile under the fusion
conditions, these constituents will be exhausted through the fume hood system.
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15. Waste Management
15.1. Refer to the appropriate chemical separation methods for waste disposal information.
16. References
Cited References
16.1. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Americium-241 in Building Materials for Environmental Remediation Following
Radiological Incidents. Revision 0, EPA 402-R14-007. Office of Air and Radiation,
Washington, DC. Available at: www.epa.gov/narel.
16.2. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Pu-238 and Pu-239/240 in Building Materials for Environmental Remediation
Following Radiological Incidents. Revision 0, EPA 402-R14-006. Office of Air and
Radiation, Washington, DC. Available at: www.epa.gov/narel.
16.3. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Radium-226 in Building Materials for Environmental Remediation Following
Radiological Incidents. Revision 0, EPA 402-R14-002. Office of Air and Radiation,
Washington, DC. Available at: www.epa.gov/narel.
16.4. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Total Radiostrontium (Sr-90) in Building Materials for Environmental
Remediation Following Radiological Incidents. Revision 0, EPA 402-R14-001. Office
of Air and Radiation, Washington, DC. Available at: www.epa.gov/narel.
16.5. U.S. Environmental Protection Agency (EPA). 2014. Rapid Radiochemical Method
for Isotopic Uranium in Building Materials for Environmental Remediation Following
Radiological Incidents. Revision 0, EPA 402-R14-005. Office of Air and Radiation,
Washington, DC. Available at: www.epa.gov/narel.
16.6. U.S. Environmental Protection Agency (EPA). 2009. Method Validation Guide for
Qualifying Methods Used by Radiological Laboratories Participating in Incident
Response Activities. Revision 0. Office of Air and Radiation, Washington, DC. EPA
402-R-09-006, June. Available at: www.epa.gov/narel.
16.7. U.S. Environmental Protection Agency (EPA). 2012. Radiological Laboratory Sample
Analysis Guide for Incident Response — Radionuclides in Soil. Revision 0. Office of
Air and Radiation, Washington, DC. EPA 402-R-12-006, September 2012. Available
at: www.epa.gov/narel.
16.8. MARLAP. Multi-Agency Radiological Laboratory Analytical Protocols Manual.
2004. Volumes 1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG 1576, NTIS
PB2004-105421, July. Available at: www.epa.gov/radiation/marlap.
16.9. ASTM Dl 193, "Standard Specification for Reagent Water" ASTM Book of Standards
11.01, current version, ASTM International, West Conshohocken, PA.
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Other References
16.10. Maxwell, S., Culligan, B. and Noyes, G. 2010. Rapid method for actinides in
emergency soil samples, RadiochimicaActa. 98(12): 793-800.
16.11. Maxwell, S., Culligan, B., Kelsey-Wall, A. and Shaw, P. 2011. "Rapid Radiochemical
Method for Actinides in Emergency Concrete and Brick Samples," Analytica Chimica
Acta. 701(1): 112-8.
16.12. U.S. Environmental Protection Agency (EPA). 2010. Rapid Radiochemical Methods
for Selected Radionuclides in Water for Environmental Restoration Following
Homeland Security Events, Office of Air and Radiation. EPA 402-R-10-001, February.
Revision 0.1 of rapid methods issued October 2011. Available at: www.epa.gov/narel/.
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17. Tables, Diagrams, and Flow Charts
17.1. Fusion Flow Chart
Timeline for Rapid Fusion and Preparation of Building
Materials Samples for Precipitation and Analysis
Rapid Fusion (Steps 11.1 - 11.9)
1. Add concrete or brick sample to 250 mL Zr crucible.
2. Add appropriate tracers/carriers.
3. Dry on hot plate.
4. Add 10-15 g NaOH pellets to crucible.
5. Heat -15 min. at 600 °C.
6. Remove from furnace and allow to cool.
V
Prepare for precipitations (Step 11.1.10)
1. Add waterto crucibles to dissolve fused sample as
much as possible and transferto centrifuge tubes.
2. Warm on hotplate to dissolve/loosen solids.
3. Transfer to 225 mL centrifuge tube.
4. Rinse crucibles well with water and transferto tubes.
5. Fusion solution is ready foractinide orRa/Sr
precipitations.
Elapsed Time
45 minutes
11/2 hours
Continued on Appropriate
Procedure Chart
I
Actinide
Precipitation
Procedure
X
/
Carbonate (concrete)
or Phosphate (brick)/
Fluoride
Precipitations for Sr
Procedure
\
/
Carbonate
Precipitation for Ra
Procedure
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17.2. Actinide Precipitation Flow Chart
Actinide Precipitation Procedure
Actinide
Precipitation
Procedure
Continued from 17.1 Fusion Flow Chart
1. Add Fe and La to each tube.
2. Dilute to 180 ml_ with water.
3. Cool to room temperature in ice bath.
4. Add Ca and (NH4)2HPO4 to each tube. Cap and mix.
5. Add TiCI3 to each tube. Cap and mix.
6. Cool in ice bath foMO min.
7. Centrifugefor6 min and pouroff supernate solution.
8. Redissolve in 1.5M HCI.
9. Dilute to 170 mLwith 0.01M HCI.
10. Add La, TiCI3 and HF and cool in ice bath for 10 min.
11. Centrifugefor 10 min and pouroff supernate solution.
12. Redissolve in 5mL 3M HNO3-0.25M H3BO3 + 6 mL
HNO3 +7 mL 2M AI(NO3)3 + 3 mL 3M HNO3, warming
to dissolve in 50 mL centrifuge tubes.
13. Centrifuge to remove any trace solids.
14. Transfer sample solutions to newtubes or beakers
and discard any traces of solids.
15. Allow sample solutions to cool to room temperature.
16. Analyze sample solutions forspecific actinides using
rapid methods forspecific actinides in building
materials.
Elapsed Time
3 hours
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17.3. Strontium Precipitation Flow Chart
Strontium Precipitation Procedure (Concrete)
CaCO3 / CaF2
Precipitation for Sr
in Concrete
Procedure
Elapsed Time
Continued from 17.1 Fusion Flowchart
1. Dilute to 150 ml with water.
2. Add 15 ml of concentrated HCL to each tube.
3. Add 1 ml 1.25M Ca (NO3)2, 100 mg Fe and 25 ml
2M Na2CO3 to each tube.
4. Cool 10 min in ice bath.
5. Centrifuge for 5 min. and pour off supernate solution.
6. Add 1.5M HCI to each tube to redissolve each
sample.
7. Dilute each tube to-170 ml with 0.01 M HCI.
8. Add 22 ml concentrated HF and cool in ice bath for
10 min.
9. Centrifuge for 6 min and pour off supernate solution
10. Redissolve in 5 ml 3MHN03-0.25M H3BO3 + 5mL
concentrated HNO3 +5 ml 2M AI(NO3)3 + 5 ml 3M
HN03.
11. Cap and mix using shaking orvortex stirrer.
12. Centrifuge for 5 min and discard trace solids.
13. Analyze sample solutions for 90Sr using 90Sr method
for building materials.
21/2 hours
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Strontium Precipitation Procedure (Brick)
Ca3(PO4)2 / CaF2
Precipitation for Sr
in Brick Procedure
Continued from 17.1 Fusion Flowchart
1. Dilute to 150 ml with water.
2. Add 2 ml 1.25M Ca(NO3)2, 50 mg Fe, and 5 ml
3.2M (NH4)2HPO4 to each tube.
3. Centrifuge for 5 min and pour off supernate.
4. Redissolve in -60 ml_1.5M HCL
5. Dilute to 170 ml with 0.01M HCI.
6. Add 22 ml Concentrated HF and wait 10 min.
7. Centrifuge for 6 min and pour off supernate.
8. Redissolve in 5 ml 3M HNO3-0.25M H3BO3 + 5 ml
concentrated HNO3 +5 ml 2M AI(NO3)3 + 5 ml 3M
HN03.
9. Cap and mix using vortex stirrer.
10. Centrifuge for 5 min and discard trace solids.
11. Analyze sample solutions for 90Sr using 90Sr method
for building materials.
Elapsed Time
21/2 hours
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17.4. Radium Precipitation Flow Chart
Carbonate Precipitation for Radium Procedure
Carbonate
Precipitation for
Radium Procedure
Continued from 17.1 Fusion Flowchart
1. Dilute to 150 ml with water.
2. Add 10 ml concentrated HCI to each tube.
3. Add 0.5 ml 1.25M Ca(NO3)2 and 2M Na2CO3 to each
tube.
4. Cool 10 min in ice bath.
5. Centrifuge for 6 min and pour off supernate solution.
6. Redissolvein10-ml_ 1.5 M HCL.
7. Transfer to 50 ml centrifuge tubes.
8. Rinse 225-mL tube with 10-mL 1.5M HCL and
transfer to 50-mLtube.
9. Cap and mix by shaking or using vortex stirrer.
10. Centrifuge for 5 min and discard trace solids.
11. Analyze sample solutions for 226Ra using 226Ra
method for building materials.
Elapsed Time
3 hours
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Appendix:
Rapid Technique for Milling and Homogenizing Concrete and Brick Samples
Al. Scope and Application
ALL Concrete or brick samples may be received as powder, core samples or other size
pieces or chunks. The goal is to obtain representative sample aliquants from
homogeneous amounts of sample.
Al .2. The ball mill method describes one approach for the rapid, gross preparation of
concrete or brick samples to yield representative 1-2 g aliquant for radiochemical
analysis of non-volatile radionuclides. The method addresses steps for splitting,
drying, and milling of 50-2,000 g concrete or brick samples. The concrete or brick
sample must be reduced to pieces or fragments less than ~ 25 mm in diameter prior
to using the ball mill. This can be done with a hydraulic press or mallet.
Al .3. The method is designed to be used as a preparatory step for the attached methods
for fusion of concrete or brick for 241Am, 2te/240Pu, U, *Sr, and 226Ra. It may also
be applied to other matrices whose physical form is amenable to pulverization in
the ball mill.
Al .4. If the levels of activity in the sample are low enough to permit safe radiological
operations, up to 2 kg of concrete or brick can be processed.
A1.5. For smaller amounts of concrete or brick samples, a drill with masonry bit can be
used in a lab hood inside a plastic bag to collect the powder that results.
A2. Summary of Methods
A2.1. This method uses only disposable equipment to contact the sample, minimizing the
risk of contamination and cross-contamination and eliminating concerns about
adequate cleaning of equipment.
A2.2. Extraneous material, such as rocks or debris may be removed prior to processing
the sample unless the project requires that they be processed as part of the sample.
NOTE: The sample mass is generally used for measuring the size of solid samples. The initial
process of acquiring a representative aliquant uses the volume of the sample, as the total
sample size is generally based on a certain volume of concrete or brick (e.g., 500 mL).
A2.3. The entire sample as received (after reducing fragment size to less than -25 mm
diameter) is split by coning and quartering until 75-150 mL of concrete or brick are
available for subsequent processing. If less than 450 mL of concrete or brick is
received, the entire sample is processed.
A2.4. The concrete or brick is transferred to a paint can or equivalent. Percent solids are
determined, if required, by drying in a drying oven. A mallet and plastic bag or
hydraulic press may be needed to break up larger pieces.
A2.5. Grinding media (stainless steel or ceramic balls or rods) are added, and the sample
is milled to produce a finely-ground, well-homogenized, powder with predominant
particle size less than 250 micrometers (um).
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NOTE: A mortar and pestle may also be used as needed to grind the sample further.
A2.6. If the sample may contain discreet radioactive particles (DRPs), particles larger
than a nominal size of 150 um are screened for radioactivity, and further milled, or
processed with another appropriate method to ensure that they will be chemically
available for subsequent processing.
A2.7. The resulting milled sample is stored in, and aliquanted directly from, the container
used for pulverization.
A2.8. The drill bit method involves drilling into the sample using a drill bit. The
operation is performed inside a disposable plastic bag in a hood so that the drilled
out sample is caught within the plastic bag (this also minimizes the spread of
contamination). A drill bit such as a H-inch carbide bit is recommended. The holes
should be drilled in such a way as to obtain representative powdered samples. The
drill bit should be cleaned between uses on different samples using soap and water.
A3. Definitions, Abbreviations, and Acronyms
A3.1. Discrete Radioactive Particles (DRPs or "hot particles"). Paniculate matter in a
sample of any matrix where a high concentration of radioactive material is
contained in a tiny particle (um range).
A3.2. Multi-Agency Radiological Analytical Laboratory Protocols (MARLAP) Manual
(Reference A16.3).
A3.3. ASTM C999 Standard Practice for Soil Sample Preparation for the Determination
of Radionuclides (Reference A16.4).
A4. Interferences
A4.1. Radi ol ogi cal Interference s
A4.1.1. Coning and quartering provides a mechanism for rapidly decreasing the
overall size of the sample that must be processed while optimizing the
representativeness of the subsampling process. By decreasing the time and
effort needed to prepare the sample for subsequent processing, sample
throughput can be significantly improved. Openly handling large amounts
of highly contaminated materials, however, even within the containment
provided by a fume hood, may pose an unacceptable risk of inhalation of
airborne contamination and exposure to laboratory personnel from
radioactive or other hazardous materials. Similarly, it may unacceptably
increase the risk of contamination of the laboratory.
A4.1.2. In such cases, coning and quartering process may be eliminated in lieu of
processing the entire sample. The time needed to dry the sample will
increase significantly, and the container size and the number and size of
grinding media used will need to be adjusted to optimize the milling
process. See ASTM C999 for an approach for homogenization and milling
of larger soil samples.
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A4.1.3. The precise particle size of the milled sample is not critical to subsequent
processes. However, milling the sample to smaller particle sizes, and
thorough mixing, both facilitate representative sub-sampling by
minimizing the amount of sample that is not pulverized to fine mesh and
must be discarded. Additionally, subsequent fusion and digestion
processes are more effective when performed on more finely milled
samples.
A4.1.4. This method assumes that radioactivity in the sample is primarily adsorbed
onto the surface of particles, as opposed to being present as a hot particle
(see discussion of DRPs below). Thus, nearly all of the activity in a
sample will be associated with sample fines. By visually comparing the
sample to a qualitative standard of 50-100 mesh size particles, it is
possible to rapidly determine whether the sample is fine enough to
facilitate the subsequent fusion or digestion. This method assumes that
when greater than 95% of the sample is as fine or finer than the 50-100
mesh sample, bias imparted from losses of larger particles will be
minimal.
A4.1.5. If the sample was collected near the epicenter of a radiological dispersal
device (RDD) or improvised nuclear device (IND) explosion, it may
contain millimeter- to micrometer-sized particles of contaminant referred
to as "discrete radioactive particles" or DRPs. DRPs may consist of small
pieces of the original radioactive source and thus may have very high
specific activity. They may also consist of chemically intractable material
and present special challenges in the analytical process. Even when the
size is reduced to less than 50-100 mesh, these particles may resist fusion
or digestion of the solids into ionic form that can be subjected to chemical
separations.
A4.1.6. When DRPs may be present, this method isolates larger particles by
passing the sample through a disposable 50-mesh screen after which they
can be reliably checked for radioactivity. DRPs may reliably be identified
by their very high specific activity, which is readily detectable, since they
show high count rates using hand-held survey equipment such as a thin-
window Geiger-Muller (G-M) probe.
A4.1.7. When present, DRPs may be further milled and then recombined with the
original sample. Alternatively, the particles, or the entire sample may need
to be processed using a different method capable of completely
solubilizing the contaminants such that the radionuclides they contain are
available for subsequent chemical separation.
A5. Safety
A5.1. General
A5.1.1. Refer to your safety manual for concerns of contamination control,
personal exposure monitoring, and radiation dose monitoring.
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A5.1.2. Refer to your laboratory's chemical hygiene plan (or equivalent) for
general safety rules regarding chemicals in the workplace.
A5.2. Radiological
A5.2.1. Refer to your radiation safety manual for direction on working with
known or suspected radioactive materials.
A5.2.2. This method has the potential to generate airborne radioactive
contamination. The process should be carefully evaluated to ensure that
airborne contamination is maintained at acceptable levels. This should
take into account the activity level, and physical and chemical form of
contaminants possibly present, as well as other engineering and
administrative controls available.
A5.2.3. Hot Particles (DRPs)
A5.2.3.1. Hot particles will usually be small, on the order of 1 mm or
less. Typically, DRPs are not evenly distributed in the
media, and their radiation emissions are not uniform in all
directions (anisotropic). Filtration using a 0.45 um or
smaller filter may be needed following subsequent fusion to
identify the presence of smaller DRPs.
A5.2.3.2. Care should be taken to provide suitable containment for
filter media used in the pretreatment of samples that may
have DRPs, because the particles become highly statically
charged as they dry out and will "jump" to other surfaces
potentially creating contamination-control issues.
A5.3. Method-Specific Non-Radiological Hazards
A5.3.1. This method employs a mechanical shaker and should be evaluated for
personnel hazards associated with the high kinetic energy associated with
the milling process.
A5.3.2. This method employs a mechanical shaker and involves vigorous agitation
of steel or ceramic balls inside steel cans. The process should be evaluated
to determine whether hearing protection is needed to protect the hearing of
personnel present in the area in which the apparatus is operated.
A6. Equipment and supplies
A6.1. Balance, top-loading, range to accommodate sample size encountered, readability
to ±1%.
A6.2. Drying oven, at 110±10 °C.
A6.3. Steel paint cans and lids (pint, quart, 2-quart, 1-gallon, as needed).
A6.4. Steel or ceramic grinding balls or rods for ball milling, -15-25 mm diameter. The
size and number of grinding media used should be optimized to suit the types of
concrete or brick, the size of the can, and the volume of soil processed.
A6.5. Disposable wire cloth - nominal 48 mesh size (-300 um).
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A6.6. Disposable sieves, U.S. Series No. 50 (300 um or 48 mesh) and U.S. Series No.
100 (150 um or 100 mesh).
A6.7. Red Devil 5400 mechanical paint shaker or equivalent.
A6.8. Disposable scoop, scraper, tongue depressor or equivalent.
A7. Reagents and Standards
No reagents needed.
A8. Sample Collection, Preservation and Storage
A8.1. Samples should be collected in appropriately sized plastic, metal or glass
containers.
A8.2. No sample preservation is required. If samples are to be held for an extended period
of time, refrigeration may help minimize bacterial growth in the sample.
A8.3. Default sample collection protocols generally provide solid sample volumes
equivalent to approximately 500 mL of sample. Such samples will require two
splits to obtain a -100 mL sample.
A9. Quality Control
A9.1. Batch quality control results shall be evaluated and meet applicable Analytical
Protocol Specifications (APS) prior to release of unqualified data. In the absence of
project-defined APS or a project-specific quality assurance project plan (QAPP),
the quality control sample acceptance criteria defined in the laboratory quality
manual and procedures shall be used to determine acceptable performance for this
method.
A9.2. Quality control samples should be initiated as early in the process as possible.
Since the risk of cross-contamination using this process is relatively low, initiating
blanks and laboratory control samples at the start of the chemical separation
process is acceptable. If sufficient sample is available, a duplicate sample should be
prepared from the two discarded quarters of the final split of the coning and
quartering procedure.
A10. Procedure
NOTE: This method ensures that only disposable equipment comes in contact with sample materials
to greatly minimize the risk of sample cross-contamination and concerns about adequate cleaning of
equipment. Under certain circumstances (disposable sieves are not available, for example), careful,
thorough cleaning of the sieves with water and the ethanol may be an option.
A10.1. If necessary, reduce the concrete or brick particle diameter to less than -25 mm
using a hydraulic press, mallet, or alternate equipment capable or reducing the
fragment size.
A10.2. Estimate the total volume of sample, as received.
NOTE: If the sample is dry, the risk of resuspension and inhalation of the solids may be
determined to be unacceptable. In such cases, the entire sample may be processed in a larger
can. The drying and milling time will be increased, and more grinding media will be
required to obtain a satisfactory result.
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NOTE: The next step uses absorbent paper in the reverse fashion for the normal use of this
type of paper; it allows for a smooth division of the sample and control of contamination.
Al 0.2.1. Spread a large piece of plastic backed absorbent paper, plastic side up
in a hood.
A10.2.2. If the sample volume is less than 450 mL, there is no benefit to coning
and quartering.l
A10.2.2.1. Carefully pour the sample onto the paper.
Al0.2.2.2. Remove extraneous material, such as rocks or debris,
unless the project requires that such material be processed
as part of the sample. Continue with Step A10.2.5.
A10.2.3. If the sample volume is greater than -450 mL, carefully pour the entire
sample into a cone onto the paper.
Remove extraneous material, such as rocks or debris unless the project
requires that such material be processed as part of the sample.
A10.2.4. If levels of gross activity in the sample permit, the sample is split at
least twice using the coning and quartering steps that follow.
NOTE: Unused quarters are considered representative of the original sample and
may be reserved for additional testing. The process should be carried out
expediently to minimize loss of volatile components in the sample, especially if
volatile components or percent solids are to be determined.
A10.2.4.1. Spread the material into a flat circular cake of soil using a
tongue depressor or other suitable disposable implement.
Divide the cake radially and return two opposing quarters
to the original sample container.
Al0.2.4.2. Reshape the remaining two quarters into a smaller cone,
and repeat Step A10.2.2.1 until the total volume of the
remaining material is approximately 100-150 mL.
NOTE: Tare the can and lid together. Do not apply an adhesive
label. Rather, la bel the can with permanent marker since the can
will be placed in a drying oven. The lid should be labeled
separately since it will be removed from the can during drying.
A10.2.5. Transfer the coned and quartered sample to a tared, labeled 1-pint paint
can. If the total volume was less than -450 mL, transfer the entire
sample to a tared, labeled 1-quart paint can.
NOTE: Constant mass may be determined by removing the container from the
oven and weighing repeatedly until the mass remains constant with within 1% of
the starting mass of the sample. This determination may also be achieved
operationally by observing the time needed to ensure that 99% of all samples will
obtain constant mass.
1 International Union of Pure and Applied Chemistry (IUPAC). 1997. Compendium 1675 of Chemical Terminology,
2nd ed. (the "Gold Book"). Compiled by A. D. (Reference A16.1).
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A10.3. Place the can (without lid) in an oven at 110±10 °C and dry the concrete or brick
to constant mass.
NOTE: Concrete or brick samples may be dry enough such that heating prior to
homogenizing the sample is not required.
A10.4. Weigh the combined mass of the can, sample, and lid. If the percent solids are
required see Section A12.1 calculations. Remove can from oven and allow to
cool.
A10.5. Add five 1.5 cm stainless steel or ceramic balls or rods to the can. Replace the lid
and seal well.
A10.6. Shake the can and contents for 5 minutes, or longer, as needed to produce a
finely-milled, well-homogenized, sample.
NOTE: Although the precise particle size of the milled sample is not critical, complete
pulverization and fine particle size facilitates representative sub-sampling and subsequent
fusion or digestion processes. A qualitative standard can be prepared by passing quartz sand
or other milled material through a 50-mesh and then a 100-mesh screen. The portion of the
sample retained in the 100 mesh screen can be used as a qualitative visual standard to
determine if samples have been adequately pulverized.
A10.7. Visually compare the resulting milled sample to a qualitative 50-100 mesh
pulverized sample (-150-300 um or 50-100 mesh using the Tyler screen scale).
The process is complete once 95% of the sample (or greater) is as fine, or finer,
than the qualitative standard. If, by visual estimation, more than -5% of total
volume of the particles in the sample appear to be larger than the particle size in
the standard, return the sample to the shaker and continue milling until the process
is complete.
A10.8. Following milling, a small fraction of residual larger particles may remain in the
sample.
A10.8.1. If the sample was collected close to the epicenter of an RDD or IND
explosion, it may also contain particles of contaminant referred to as
"discrete radioactive particles" or DRPs. In such a case, the larger
particles should be isolated by passing through a disposable 48 mesh
screen and checked for radioactivity. DRPs are readily identified by
their very high specific activity which is detectable using hand-held
survey equipment such as a thin-window G-M probe held within an
inch of the particles.
A10.8.1.1. If radioactivity is clearly detected, the sieved material is
returned to the can and ball milled until the desired mesh
is obtained. In some cases, these materials may be
resistant to further pulverization and may need to be
processed according to a method specially designed to
address highly intractable solids.
A10.8.1.2. If the presence of DRPs is of no concern, the larger
particles need not be included in subsequent subsamples
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taken for analysis. It may be possible to easily avoid
including them during aliquanting with a disposable
scoop. If not, however, they should be removed by sieving
through a nominal 50 mesh screen (disposable) prior to
further subsampling for subsequent analyses.
A10.9. Sample fines may be stored in, and aliquanted directly from, the container used
for drying and pulverization.
Al 1. Calibration and Standardization
Al 1.1. Balances used shall be calibrated using National Institute of Standards and
Technology (NIST)-traceable weights according to the process defined by the
laboratory's quality manual.
A12. Data Analysis and Calculations
A12.1. The percent solids (dry-to-as-received mass ratio) for each sample is calculated
from data obtained during the preparation of the sample as follows:
1VT — 1VT
% Solids = —^- — x 100
Where:
Mdry = mass of dry sample + labeled can + lid (g)
Mtare = tare mass of labeled can + lid (g)
Mas rec = mass of sample as received + labeled can + lid (g)
A12.2. If requested, convert the equivalent mass of sample, as received, to dry mass. Dry
mass is calculated from a measurement of the total as received mass of the sample
received as follows:
_. _ , „ . . -. % Solids
Dry SampleEquivalent = Mtotal.asrec x
Where:
Mtotai-as rec. = total mass of sample, as received (g)
A12.3. Results Reporting
A12.3.1. The result for percent solids and the approximate total mass of sample
as received should generally be reported for each result.
Al3. Method Performance
A13.1. Results of method validation performance are to be archived and available for
reporting purposes.
A13.2. Expected turnaround time is about 3 hours for an individual sample and about 4
hours per batch.
A14. Pollution Prevention.
Not applicable
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A15. Waste Management
Al5.1. All radioactive and other regulated wastes shall be handled according to
prevailing regulations.
A16. References
A16.1. International Union of Pure and Applied Chemistry (IUPAC). 1997. Compendium
of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D.
McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford. XML
on-line corrected version: http://goldbook.iupac.org/C01265.html. (2006) created
by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. Last update: 2010-
12-22.
A16.2. ALS Laboratories, Fort Collins, SOP 736.
A16.3. MARLAP. Multi-Agency Radiological Laboratory Analytical Protocols Manual.
2004. Volumes 1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG 1576,
NTIS PB2004-105421, July. Available at: www.epa.gov/radiation/marlap.
A16.4. ASTM C 999-05, "Standard Practice for Soil Sample Preparation for the
Determination of Radionuclides," Volume 12.01, ASTM, 2005.
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