www.epa.gov
May 2017
EPA 402-RI6-001
Revision 0
Rapid Method for Sodium Hydroxide Fusion
of Asphalt Matrices Prior to Americium,
Plutonium, Strontium, Radium, and Uranium
Analyses
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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Sodium Hydroxide Fusion of Asphalt Matrices
Revision History
Revision 0 Original release. 05-01-2017
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 U.S. Environmental
Protection Agency's (EPA) Office of Research and Development. It was prepared by Environmental
Management Support, Inc., of Silver Spring, Maryland, under contract EP-W-13-016, task order 014,
managed by Dan Askren. This document has been reviewed in accordance with 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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Sodium Hydroxide Fusion of Asphalt Matrices
Rapid Method for Sodium Hydroxide Fusion of Asphalt Matrices Prior
to Americium, Plutonium, Strontium, Radium, and Uranium Analyses
1. Scope and Application
1.1. The method is applicable to the sodium hydroxide fusion of asphalt 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 applies to asphalt samples collected following a radiological or
nuclear incident. The asphalt samples may be received as core samples, crushed
samples or in pieces of various sizes. The term "asphalt" is used in this procedure to
mean asphalt concrete typically used for road, parking lot, and pathway surfaces.
1.3. The rapid fusion method is rapid and rigorous, effectively digesting refractory
radionuclide particles that may be present.
1.4. Asphalt samples should be crushed and pulverized prior to taking a representative
aliquant for furnace heating and fusion. Even asphalt samples containing softer,
stickier tar and bitumin will dry when aggregate particles are pulverized, releasing a
powder that facilitates drying. The asphalt sample should be milled and sieved to
achieve a particle size small enough that representative subsamples can be taken and
representative aliquants analyzed.
1.5. After a homogeneous subsample is obtained, the asphalt aliquant is taken and heated
to destroy organics in the sample matrix. After heating, the sample aliquant is fused to
digest the asphalt sample matrix, and matrix removal steps are employed to collect and
preconcentrate the radionuclides from the alkaline fusion matrix. 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).
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1.6. 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 Radioanalytical Laboratories Participating in Incident Response Activities
(Reference 16.6), or the protocols published by a recognized standards organization
for method validation.
I.6.1. In the absence of project-specific guidance, MQOs for asphalt samples may be
based on the analytical action levels (AALs), the required method uncertainty
(mmr), and the required relative method uncertainty ((pmr) 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 heating a representative, finely milled 1-1,5-g aliquant asphalt
sample to remove organic components present followed by rapid fusion using a
sodium hydroxide process 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 phosphate precipitation, followed by a
calcium fluoride precipitation to remove silicates.
2.4. Ra is separated from the alkaline matrix using a carbonate precipitation.
2.5. The resulting solutions are subsequently processed using the methods referred to in
Steps 1.1.1-1.1.5.
3. Definitions, Abbreviations and Acronyms
3.1. Discrete Radioactive Particles (DRPs or "hot particles"). Particulate matter in a sample
of any matrix where a high concentration of radioactive material is present as a tiny
particle (
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4.2. Information regarding the elemental composition of the sample may be helpful. For
example, asphalt may have native concentrations of uranium, radium, thorium,
strontium, or barium, all of which may have an effect on the chemical separations used
following the fusion of the sample. In some cases (e.g., strontium analysis), elemental
analysis of the digestate prior to chemical separations may be necessary to determine
native concentrations of carrier elements present in the sample. The processing of
additional sample aliquants without Sr carrier added may also be utilized to determine
if a stable Sr carrier correction is needed. In a radiological emergency, this may be a
less disruptive approach than separate digestion of aliquants for elemental Sr assay.
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., Barium [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 asphalt material may be acceptable blank material for Pu, Am, and Sr
analyses, but this material will contain background levels of naturally occurring 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 sample be added as calcium nitrate to the empty
crucible as blank simulant. This step facilitates strontium phosphate and
radium carbonate precipitations from the alkaline fusion matrix.
4.4.2. Tracer yields may be slightly lower for reagent blank matrices, since asphalt
matrix components typically enhance recoveries across the precipitation steps.
4.5. Samples with elevated activity or samples that require multiple analyses from a single
aliquant 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
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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.
4.6. Blank samples, laboratory control samples (LCSs), and duplicates should be created as
early in the process as possible, following the same tracer/carrier additions, digestion
process, and sample splitting used for the field samples. In this method, quality control
(QC) samples should be initiated at the point samples are aliquanted into crucibles for
fusion.
4.7. Zirconium crucibles used in the furnace ashing and fusion process may be reused.
4.7.1. Before reuse, the crucibles should be cleaned very well using soap and water,
followed by warm nitric acid (multiple rinses) and then water. Blank
measurements should be monitored to ensure effective cleaning and control
against cross-contamination.
4.7.2. 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.
4.8. Centrifuge speeds of 3500 rotations per minute (rpm) are recommended but lower rpm
speeds may be used if 3500 rpm is not available.
4.9. Aluminum nitrate reagent typically contains trace levels of uranium contamination. To
achieve the lowest possible blanks for isotopic uranium measurements, some labs have
removed the trace uranium by passing -250 mL of the 2 Molar (M) aluminum nitrate
reagent through ~7 mL TRU Resin or UTEVA Resin, but this will have to be tested
and validated by the laboratory.
4.10. It is very important to achieve as homogeneous and representative a sample aliquant of
the asphalt as possible to allow reliable assessment of radiological contamination of
the asphalt samples taken. The asphalt sample should be milled and sieved to a 50-100
mesh particle size if possible. Radioactivity from a radiological event is deposited on
the surface of the asphalt, not inside the larger aggregate rocks, so removal of the
larger rocks via sieves still results a conservative, reliable assessment of radiological
deposition.
5. Safety
5.1. General
5.1.1. Refer to your laboratory's safety manual for concerns of contamination control,
personal exposure monitoring and radiation safety manual for radiation dose
monitoring.
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
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5.2.1. Discrete Radioactive Particles (DRPs or hot particles)
5.2.1.1. Hot particles will likely be small, on the order of 1 millimeter (mm)
or less. DRPs typically are not evenly distributed in the media and
their radiation emissions are not uniform in all directions
(anisotropic).
5.2.1.2. Asphalt 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 furnace ashing and sodium hydroxide fusion are 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 well-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.
Note: 225-mL centrifuge tubes are specified but 250-mL centrifuge tubes may also be used
instead.
6.5. Centrifuge tubes, 50-mL and 225-mL capacity.
6.6. Crucibles, 250 mL, zirconium, with lids.
6.7. 100-microliter (|xL), 200-[jL, 500-[xL, and 1-mL pipets or equivalent and appropriate
plastic tips.
6.8. 1-10 mL electronic/manual pipet(s).
6.9. Hot water bath or dry bath equivalent.
6.10. Muffle furnace capable of reaching at least 600 °C.
6.11. Tongs for handling crucibles (small and long tongs).
6.12. Tweezers or forceps.
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6.13. Sample size reduction equipment (hydraulic press, milling equipment, hammer, mallet,
etc) and sieves. 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 A for a method for homogenization of asphalt samples.
6.14. 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 and are commercially available.
7.1. Type I reagent water as defined in ASTM Standard D1193 (Reference 16.9).
7.2. Aluminum nitrate solution, 2M (A1(N03)3): Add 750 g of aluminum nitrate
nonahydrate (A1(N03)3' 9H20) to -600 mL of water and dilute with water to 1 L.
Low-levels of uranium are typically present in A1(N03)3 solution.
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 with water to
250 mL.
7.4. Boric Acid, H3BO3.
7.5. Calcium nitrate (1.25M): Dissolve 147 g of calcium nitrate tetrahydrate
(Ca(N03)2'4H20) in 300 mL of water and dilute with water to 500 mL.
7.6. Iron carrier (50 mg/mL): Dissolve 181 g of ferric nitrate (Fe(N03)3 • 9H20) dissolved
in 300 mL water and dilute with water to 500 mL. This carrier does not need to be
standardized.
7.7. Hydrochloric acid (12M): Concentrated HC1.
7.7.1. Hydrochloric acid (0.01M): Add 0.83 mL of concentrated HC1 to 800 mL of
water and dilute with water to 1 L.
7.7.2. 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.
3_i_
7.9. Lanthanum carrier (1.0 mg La /mL): Add 1.56 g lanthanum (III) nitrate hexahydrate
[La(NC>3) 3 • 6H2O] in 300 mL water, dilute with water to 500 mL. This carrier does
not need to be standardized.
7.10. Nitric acid (16M): Concentrated HNO3.
7.1.1. Nitric acid (3M): Add 191 mL of concentrated HNO3 to 700 mL of water and
dilute with water to 1 L.
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7.1.2. Nitric acid (3M)-boric acid (0.25M) solution: Add 15.4 g of boric acid and 190
mL of concentrated HNO3 to 500 mL of water, heat to dissolve, and dilute with
water to 1 L.
7.1.3. Nitric acid (7M): Add 443 mL of concentrated HNO3 to 400 mL of water and
dilute with water to 1 L.
7.1.4. Nitric acid (8M): Add 506 mL of concentrated HNO3 to 400 mL of water and
dilute with water to 1 L.
7.2. Sodium carbonate (2M): Dissolve 212 g anhydrous Na2CC>3 in 800 mL of water, then
dilute with water to 1 L.
7.3. Sodium hydroxide pellets.
7.4. Titanium (III) chloride solution (TiCh), 10 percent by mass (wt%) solution in 20-30
wt% hydrochloric acid. (This reagent is typically available commercially in this
concentration; however, if a different concentration, for example, 20% TiCI 3 is
available it may be used with an appropriate volume adjustment.)
7.5. 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
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 (Ce) 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. Quality control samples are generally specified in the laboratory's quality manual or in
a project's analytical protocol specifications (APS). At the very minimum, the
following are suggested:
9.2.1. A 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
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of samples. The concentration of the LCS should be at or near the action level
or level of interest for the project.
9.2.2. 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).
9.2.3. A sample duplicate that is equal in size to the original aliquant should be
analyzed with each batch of samples. This provides assurance that the
laboratory's sample size reduction and subsampling processes are reproducible.
9.3. Batch quality control results shall be evaluated and meet applicable 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's Quality Manual and procedures shall be used to determine
acceptable performance for this method.
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.
11.1.2.
11.1.3.
11.1.4.
11.1.5.
In accordance with the data quality objectives (DQOs) and sample processing
requirements stated in the project plan documents, remove extraneous
materials from the asphalt sample using a clean forceps or tweezers.
Weigh out a representative, finely milled 1-g aliquant of sample into a 250
mL crucible (1.5-g aliquants for °Sr analysis). See Appendix A for the
asphalt milling procedure.
Notes: For Sr and Ra analyses, a reagent blank of 100-150-mg Ca per gram of sample
(prepared by evaporating 2.5 mL of 1.25M calcium nitrate, Ca(N03)2, for radium and 3
mL of 1.25M calcium nitrate for strontium) should be added to the crucible as a blank
simulate to ensure the blank behaves like the asphalt samples during the precipitation
steps.
It is anticipated that asphalt sample material will be dry enough to aliquant without a
preliminary drying step, although this may be used if needed. Soft asphalt will dry
when aggregate particles are crushed and a white/grey powder is released that changes
the texture and minimizes the sticky nature of the organics.
Add the proper amount of tracer or carrier appropriate for the method being
used and the number of aliquants needed.
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.
Remove crucibles from hot plate and allow to cool.
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11.1.6. Place the crucibles with lids in a furnace at -200 °C using tongs, ramp
furnace to 600 °C and heat for ~1 hour (or until black tar color is gone).
11.1.7. Remove crucibles from furnace using tongs and allow to cool.
Note: If the asphalt sample residue looks like soil with the black tar color gone, it is
ready for the fusion step (11.1.9).
11.1.8. If the black tar color is not removed effectively by furnace heating alone, add
~5 mL 15.8M HNO3 and ~3 mL 30 wt% of H2O2 to each crucible. Allow to
react briefly and then place on hot plate on medium heat and heat to dryness.
Note: If a black tar color is still present, the sample aliquant may be wet-ashed and or
reheated briefly in a furnace at 600 °C as needed to destroy the organics present.
11.1.9. Add the following amounts of sodium hydroxide based on the aliquant
size/analysis required.
1 g for Pu, Am, U: 15gNaOH
1.5gforSr: 15gNaOH
1 g for Ra: lOgNaOH
11.1.10. Place the crucibles with lids in the 600 °C furnace using tongs.
11.1.11. Fuse samples in the crucibles for-15-20 minutes.
Note: Longer times may be needed for larger particles.
11.1.12. Remove hot crucibles from furnace very carefully using tongs, and transfer to
a hood.
11.1.13. 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 and dissolve
solids.
11.1.14. Transfer each fused sample to a 225 mL centrifuge tube, rinse crucibles well
with water, and transfer rinses to each 225 mL tube
11.1.15. If necessary for complete dissolution, add more water, and warm as needed
on a hotplate. Transfer rinses to each 225 mL tube until all solids have been
transferred.
11.1.16. Proceed to Section 11.2 for the actinide preconcentration procedure, 11.3 for
strontium preconcentration, or 11.4 for radium preconcentration steps.
11.2. Preconcentration of Actinides (Pu, U, or Am) from Hydroxide Matrix
Note: The Iron (Fe) and Lanthanum (La) carriers may be added to the 225 mL
centrifuge tubes prior to transferring the dissolved sample to the tubes.
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. Pipet 1 mg La/mL to each tube as follows:
Pu, U: 5-mL 1 mg La/mL
Am: 3-mL 1 mg La/mL
11.2.3. After each fused sample has been transferred to a 225-mL centrifuge tube,
ensure crucibles have been rinsed well with water, and the rinses have been
transferred to each tube.
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11.2.4. Add 10 mL 3 M HNO3 to each crucible and heat crucibles on a hot plate until
hot. Transfer the 3M HNO3 rinse to the 225 mL tube, followed by additional
rinses of water.
11.2.5. Dilute each sample to -180 mL with water.
11.2.6. Cool the 225-mL centrifuge tubes in an ice bath to approximately room
temperature.
11.2.7. Pipet 1.25M Ca(N03)2and 3.2M (NLL^HPC^ into each tube as follows:
Pu, Am: 1-mL 1.25M Ca(N03)2and 3-mL 3.2M (NH4)2HP04
U: 1-mL 1.25M Ca(N03)2 and 5-mL 3.2M (NH4)2HP04
11.2.8. Cap tubes and mix well.
11.2.9. Pipet 7 mL of 10 percent by mass (wt%) TiCh into each tube, and cap and
mix immediately.
Note: Other strengths of TiCl3 may be used, with the volume aliquot adjusted to add
an equivalent amount of TiCl3, for example, 4 mL of 16.9% or 20% TiCl3.
11.2.10. Cool 225 mL centrifuge tubes in an ice bath for-10 minutes.
11.2.11. Centrifuge tubes for -6 minutes at 3500 rpm or more or as needed.
11.2.12. Pour off the supernate and discard to waste.
11.2.13. Add 1.5M HC1 to each tube to redissolve each sample in a total volume of
-80 mL.
Note: The volume of 1.5M HC1 can be increased to reduce the amount of
lanthanum/calcium fluoride precipitate for very high calcium samples. This may help
minimize any undissolved solids in load solution.
11.2.14. Cap and shake each tube to dissolve solids as well as possible.
Note: Typically, there will be undissolved solids at this point, which is acceptable.
11.2.15. Dilute each tube to -170 mL with 0.01M HC1. Cap and mix.
11.2.16. Pipet 1 mL of 1.0 mg La/mL and 1 mL 1.25M Ca into each tube.
11.2.17. Pipet 3 mL of 10 wt% TiCl3 into each tube. Cap and mix.
11.2.18. Add -25 mL of concentrated HF into each tube. Cap and mix well.
11.2.19. Cool 225 mL centrifuge tubes in an ice bath for -10 minutes.
11.2.20. Centrifuge for -5 to 10 minutes at 3500 rpm or more or as needed.
11.2.21. Pour off supernate, and discard to waste.
11.2.22. Pipet 7 mL of 3M HNO3 - 0.25M boric acid into each tube.
11.2.23. Cap, mix and transfer contents of the tube into a labeled 50-mL centrifuge
tube.
11.2.24. Pipet 6 mL of 7M HNO3 and 8 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.
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11.2.25. Pipet 3 mL of 3M HNO3 directly into the 50-mL centrifuge tube. Cap and
mix. Samples may be heated in a water bath or hot block if needed to
dissolve, and then allowed to cool.
11.2.26. Centrifuge the 50-mL centrifuge 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.
11.2.27. Proceed directly to the Am, Pu, or U methods listed in Steps 1.1.1, 1.1.2, or
1.1.5.
11.3. Preconcentration of 90Sr from Hydroxide Matrix
11.3.1. After each fused sample has been transferred to a 225-mL centrifuge tube,
ensure crucibles have been rinsed well with water, and the rinses have been
transferred to each tube.
11.3.2. Dilute each sample to -150 mL with water.
11.3.3. Cool the 225-mL centrifuge tubes in an ice bath to approximately room
temperature.
11.3.4. Pipet 2 mL 1.25M Ca(NC>3 2,1 mL of iron carrier (50 mg/mL), and 5 mL
3.2M (NH4)2HP04 into each tube.
11.3.5. Cap tubes and mix well.
11.3.6. Allow 225-mL centrifuge tubes to sit for -10 minutes.
11.3.7. Centrifuge tubes for -6 minutes at 3500 rpm or more or as needed.
11.3.8. Pour off the supernate and discard to waste.
11.3.9. Add 1.5M HC1 to each tube to redissolve each sample in a total volume of
-60 mL.
11.3.10. Cap and shake each tube to dissolve solids as well as possible.
Note: Typically, there will be undissolved solids, which is acceptable.
11.3.11. Dilute each tube to -170 mL with 0.01M HC1. Cap and mix.
11.3.12. Add -22 mL of concentrated (28M) HF into each tube. Cap and mix well.
11.3.13. Allow 225 mL tubes to sit for -10 minutes.
11.3.14. Centrifuge for -5 tolO minutes at 3500 rpm or more or as needed.
11.3.15. Pour off supernate and discard to waste.
11.3.16. Pipet 5 mL of concentrated HNChand 5 mL of 3M HNO3 - 0.25M boric acid
into each 225-mL centrifuge tube to dissolve precipitate.
11.3.17. Cap and mix well. Transfer contents of the tube into a labeled 50-mL
centrifuge tube.
11.3.18. Pipet 5 mL of 3M HNO3 and 5 mL of 2M aluminum nitrate into each tube,
cap tube and mix.
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11.3.19. Transfer rinse solutions to 50-mL centrifuge tubes and mix well (shake or use
vortex stirrer). Samples may be heated in a water bath or hot block if needed
to dissolve, and then allowed to cool.
11.3.20. Centrifuge the 50-mL tubes at 3500 rpm for 5 minutes to remove any traces
of solids.
11.3.21. Transfer solutions to labeled beakers or new 50-mL centrifuge tubes for
further processing.
11.3.22. If solids remain, add 5 mL 3M HNC^to each tube, cap and mix well,
centrifuge for 5 minutes and add the supernate to the sample solution.
Discard any residual solids.
11.3.23. Proceed directly to the Sr method listed in Step 1.1.4.
11.4. Preconcentration of 226Ra from Hydroxide Matrix
11.4.1. After each fused sample has been transferred to a 225-mL centrifuge tube,
ensure crucibles have been rinsed well with water, and the rinses have been
transferred to each tube.
11.4.2. Dilute to-150 mL with water.
11.4.3. Add 10 mL concentrated HC1 to each tube.
11.4.4. Cap and mix each tube well.
11.4.5. Pipet 1 mL 1.25M Ca(N03)2into each tube.
11.4.6. Add 10 mL 2MNa2C03to each tube.
11.4.7. Cap tubes and mix.
11.4.8. Allow tubes to stand for -10 minutes.
11.4.9. Centrifuge tubes for 6 minutes at 3500 rpm.
11.4.10. Pour off the supernate and discard to waste.
11.4.11. Pipet 10 mL 1,5M HC1 into each tube to dissolve precipitate. Cap and mix.
11.4.12. Transfer sample solution to a 50-mL centrifuge tube.
11.4.13. Pipet 10 mL 1.5M HC1 into each 225-mL centrifuge tube to rinse. Cap and
rinse well.
11.4.14. Centrifuge the 50 mL tubes at 3500 rpm for 5 minutes to remove any traces
of solids.
11.4.15. Transfer rinse solution to 50-mL tube and shake to mix well (or use vortex
stirrer).
Note: Typically, the HC1 added to dissolve the carbonate precipitate is sufficient to
acidify the sample. If the precipitate was unusually large and suspended solids remain,
additional acid may be needed. The pH can be checked to verify it is pH 1 or less. To
acidify the pH <1, add 1 or 2 mL of concentrated hydrochloric acid to the solution and
get it to clear. Tubes may be warmed in a water bath to help dissolve samples.
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11.4.16. If solids remain, add 5-mL 1,5M HC1 to each tube, cap and mix well,
centrifuge for 5 minutes and add the supernate to the sample solution.
Discard any residual solids.
11.4.17. Proceed directly to the Ra method listed in Step 1.1.3.
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.
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 HN03 so that load solution acidity is maintained when
valence adjustment reagents are added.
For a single split, the effective size of sample is calculated:
Wa=Ws^f- (l)
Where:
Ws = original sample size, in the units designated by the project manager (e.g.,
kg, 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, the equation
above (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 asphalt samples by this dissolution
method may be found in the attached appendices.
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13.3. Expected turnaround time per sample
13.3.1. For a representative, finely ground 1-g aliquant of sample, the furnace
heating and fusion steps should add approximately 3.75 hours per batch to
the time specified in the individual chemical separation methods.
13.3.2. The preconcentration steps should add approximately 0.75 to 1 hour per
batch for a total of 4.5 to 4.75 hours.
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 that may be volatile under the fusion
conditions, these constituents will be exhausted through the fume hood system.
15. Waste Management
15.1. Refer to the appropriate chemical separation methods for waste disposal information.
16. References
Cited References
16.1. EPA 2013. Rapid Radiochemical Methodfor Americium-241 in Building Materials for
Environmental Remediation Following Radiological Incidents. Office of Air and
Radiation, Washington, DC. EPA. Available here.
16.2. EPA 2013. Rapid Radiochemical Methodfor Pu-238 and Pu-239/240 in Building
Materials for Environmental Remediation Following Radiological Incidents. Office of
Air and Radiation, Washington, DC. Available here.
16.3. EPA. Improved Rapid Radiochemical Methodfor Radium-226 in Building Materials
for Environmental Remediation Following Radiological Incidents. Office of Air and
Radiation, Washington, DC. Not yet available.
16.4. EPA 2013. Rapid Radiochemical Methodfor Total Radiostrontium (Sr-90) in Building
Materials for Environmental Remediation Following Radiological Incidents. Office of
Air and Radiation, Washington, DC. Available here
16.5. EPA 2013. Rapid Radiochemical Methodfor Isotopic Uranium in Building Materials
for Environmental Remediation Following Radiological Incidents. Office of Air and
Radiation, Washington, DC. Available here.
16.6. 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 here.
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16.7. 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. Available here. EPA 2004.
16.8. EPA 2004. Multi-Agency Radiological Laboratory Analytical Protocols Manual
(MARLAP). Volumes 1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG
1576, NTIS PB2004-105421, July. Available here.
16.9. ASTM D1193, "Standard Specification for Reagent Water" ASTM Book of Standards
11.01, current version, ASTM International, West Conshohocken, PA.
Other References
16.10. Maxwell, S., Culligan, B. andNoyes, G. 2010. Rapid method for actinides in
emergency soil samples, Radiochimica Acta. 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. Maxwell, S., Culligan, B., and Hutchison, J. 2014. "Rapid Determination of Actinides
in Asphalt Samples," J. Radioanalytical and Nuclear Chemistry 299:1891-1901
16.13.EPA 2010. Rapid Radiochemical Methods for Selected Radionuclides in Water for
Environmental Restoration Following Homeland Security Events, Office of Air and
Radiation, (February). EPA 402-R-10-001, February. Revision 0.1 of rapid methods
issued October 2011. Available here.
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17. Tables, Diagrams, and Flow Charts
17.1. Fusion Flow Chart
Timeline for Rapid Fusion and Preparation of Asphalt
Samples for Precipitation and Analysis
Elapsed Time
3 hours
Continued on Appropriate
Procedure Chart
Actinide
Precipitation
Procedure
Carbonate
Precipitation for Ra
Procedure
Phosphate/Fluoride
Precipitations for Sr
Procedure
Prepare for Precipitations (Step 11.1.13)
1. Add ~ 25-50 mL water to each crucible —8-10
minutes after removal from furnace (11.1.13).
2. Warm on hotplate to dissolve/loosen solids (11.1.13).
3. Transfer to 225 mL centrifuge tube. Rinse crucibles
well with water/acid and transferto tubes (11.1.14).
4. Fusion solution is ready foractinide or Ra/Sr
precipitations (Sections 11.2-11.4).
Rapid Fusion (Step 11.1)
1. Add asphalt sample to 250 mL Zr crucible (11.1.2).
2. Add proper amount of tracers/carriers (11.1.3).
3. Dry on hot plate on medium heat (11.1.4).
4. Remove crucibles and allow to cool (11.1.5).
5. Place crucibles with lids in furnace at -200 °C and
ramp immediately to 600 °C (11.1.6).
6. Heat in furnace at 600 °C for 1 hour (11.1.6).
7. Remove crucibles and allow to cool (11.1.7).
8. Add 10-15 g NaOH pellets to crucible (11.1.9).
9. Heat -20 min. at 600 °C (11.1.10-11.1.11).
10. Remove from furnace and allow to cool in hood
(11.1.12).
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17.2. Actinide Precipitation Flow Chart
Actinide Precipitation Procedure
±
Actinide
Precipitation
Procedure
y
Continued from 17.1 Fusion Flow Chart
1. Add Feand La to each tube (11.2.1-11.2.2).
2. Ensure crucibles were rinsed well with water and
rinses were transferred to each tube. (11.2.3).
3. Add 10 mL 3M HN03 and heatuntil hot. Transferto 225-
mL tube, with additional water rinses (11.2.4)
4. Dilute to 180 mL with water (11.2.5).
5. Cool to room temperature in ice bath (11.2.6).
6. Add 1.25M Ca(N03)2 and 3.2M (NH4)2HP04 to each
tube. Cap and mix (11.2.7-11.2.8).
7. Add 7mL 10% TiCI3 to each tube. Cap and mix
(11.2.9).
8. Cool in ice bathfor~10 min (11.2.10).
9. Centrifuge for 6 min and pour off supernate (11.2.11-
11.2.12).
10. Redissolve in 1.5M HCI to a volume of -80 mL. Cap
and shake well (11.2.13-11.2.14).
11. Dilute to 170 mL with 0.01M HCI. Add 1mLLa and 1
mL1.25M Ca (11.2.15-11.2.16).
12. Add 3mL 10% wt TiCI3 and concentrated (28M) HF
and cool in ice bath for10 min (11.2.17-11.2.19).
13. Centrifuge for 5-10 min and pouroff supernate
(11.2.20-11.2.21).
14. Redissolve in 7mL 3M HNO3-0.25M H3BO3+ 6mL
7M HN03 + 8 mL 2M AI(N03)3 + 3mL 3M HN03,
warming to dissolve in 50 mL centrifuge tubes
(11.2.22-11.2.25).
15. Centrifuge for 5 minutes to remove any trace solids
(11.2.26).
16. Transfer sample solutions to newtubes or beakers
and discard any traces of solids (11.2.26).
17. Analyze sample solutions forspecific actinides using
rapid methods forspecific actinides in building
materials.
Elapsed Time
v 43A hours
17.3. Strontium Precipitation Flow Chart
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Strontium Precipitation Procedure
Ca3(P04)2 / CaF2
Precipitation for Sr
Procedure
_y
Continued from 17.1 Fusion Flowchart
I. Dilute to 150 mL with water. Cool in ice bath (11.3.2-
11.3.3).
Add 2 mL 1.25 M Ca(N03)2, 1 mL Fe carrier, and 5
mL3.2M (NH4)2HP04 to each tube. Mix and allow to
sit for ~10 minutes (11.3.4-11.3.6).
Centrifuge for6 min. and pour off supernate (11.3.7-
11.3.8).
Redissolve in -60 mL 1.5M HCI. Cap tubes and mix
well (11.3.9-11.3.10).
Dilute to 170 mL with 0.01 M HCI (11.3.11).
Add 22 mL concentrated (28M) HF and wait 10 min
(11.3.12-11.3.13).
Centrifuge for 5-10 min and pour off supernate
(11.3.14-11.3.15).
Redissolve in 5mL 3M HNO3-0.25M H3B03 + 5mL
concentrated HN03 +5 mL 2M AI(N03)3 + 5mL 3M
HN03 (11.3.16-11.3.18).
Transfer to 50 mL tube Cap and mix using vortex
stirrer (11.3.19).
10. Centrifuge for 5 min and discard trace solids
(11.3.20).
II. Analyze sample solutions for 90Sr using 90Sr method
for building materials.
2.
9.
Elapsed Time
43A hours
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17.4. Radium Precipitation Flow Chart
Carbonate Precipitation for Radium Procedure
\
f
Carbonate
Precipitation for
Radium Procedure
y
Continued from 17.1 Fusion Flowchart
1. Dilute to 150 mL with water. Add 10 mL concentrated
HCI. Cap and mix (11.4.2-11.4.4).
2. Add 1 mL 1.25M Ca(N03)2 and 10 mL 2M Na2C03 to
each tube. Cap and mix (11.4.5-11.4.7).
3. Allowto stand 10min (11.4.8).
4. Centrifuge for 6 min. Pour off supernate and discard
waste(11.4.9-11.4.10).
5. Redissolvein 10 mL1.5 M HCI. Cap and mix
(11.4.11).
6. Transfer to 50 mL centrifuge tubes (11.4.12).
7. Rinse 225 mL tube with 10 mL 1.5M HCI and transfer
to 50 mL tube. Cap and mix (11.4.13).
8. Centrifuge for 5 minutes to remove solids. (11.4.14)
9. Transfer to 50 mL tube. Cap and mix using vortex
stirrer (11.4.15).
10. If solids remain, add 5 mL 1.5M HCI to tube. Cap and
mix well. Centrifuge for5 min and discard trace
solids (11.4.16).
11. Analyze sample solutions for 226Ra using 226Ra
method forbitumin, aggregate, stone orothersolid
samples.
Elapsed Time
v 41/2 hours
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Appendix:
Rapid Technique for Milling and Homogenizing Asphalt Samples
A1. Scope and Application
A1.1. Asphalt samples may be received as core samples, chunks or crushed pieces. The
goal is to obtain representative sample aliquants from homogeneous amounts of
sample. Significant effort should be applied to ensure representative sampling of
the asphalt materials.
A1.2. This method describes one approach for the rapid, gross preparation of asphalt
samples to yield representative 1-1.5-g aliquant for radiochemical analysis of non-
volatile radionuclides. The method addresses steps for splitting, and milling of 50-
1000-g asphalt samples. The sample must be reduced to small non-sticky pieces
prior to using the ball mill. This can be done with a hydraulic press or heavy
hammer.
A1.3. The method is designed to be used as a preparatory step for the attached methods
241 238 239/240
for furnace heating and fusion of asphalt for measurement of Am, Pu, Pu,
U, 90Sr, and 226Ra. It may also be applied to other matrices whose physical form is
amenable to pulverization.
A1.4. If the levels of activity in the sample are low enough to permit safe radiological
operations, up to 1 kg of asphalt can be processed.
A2. Summary of Methods
A2.1. This method uses disposable equipment or materials to contact the sample when
possible, minimizing the risk of contamination and cross-contamination and
eliminating concerns about adequate cleaning of equipment.
A2.2. The entire sample as received (after reducing fragment size by pulverizing and
crumbling into small particles) is split by coning and quartering until -75-250 mL
of the asphalt is available for subsequent processing. If less than -450 mL of
asphalt is received, the entire sample is processed.
Note: Large chunks of asphalt will require initial crushing prior to coning and quartering.
A2.3. The asphalt is transferred to a hydraulic press and crushed. Alternately, the asphalt
may be crushed with a heavy hammer while in plastic bags and enclosed in
aluminum foil loaf or casserole pan. After crushing, the flattened asphalt may be
easily crumbled by hand. A ball mill approach with disposable paint cans is used to
mill the samples into fine particles after crushing and crumbling of the asphalt
pieces, which become drier and non-sticky when pulverized and dust is released.
A2.4. Other milling apparatus, such as lab pulverizers/crushers, also could be used to mill
the asphalt sample to finely ground, well-homogenized, particles, but not
recommended. In this case, effort must be made to ensure no sample carry-over
effects occur between the processing of individual samples. A disposable approach
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without the risk of sample carry-over contamination using a hammer/press is
preferred.
A2.5. Additional replicate analyses may also be performed to provide further assurance
that analytical results are representative of asphalt samples received.
A3. Definitions, Abbreviations, and Acronyms
A3.1. Discrete Radioactive Particles (DRPs or hot particles). Particulate matter in a
sample of any matrix where a high concentration of radioactive material is
contained in a tiny particle (< 1 mm).
A3.2. Multi-Agency Radiological Analytical Laboratory Protocols (MARLAP) Manual
(Reference A16.1) provides guidance for the planning, implementation, and
assessment phases of those projects that require the laboratory analysis of
radionuclides.
A4. Interferences
A4.1. Radiological Interferences
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 sub sampling 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.
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 enough to pass through a 30
mesh sieve (~ 600 [j,m particle size) and must be discarded. Milling to a
smaller particle size facilitates a homogeneous dispersion of particles and
enhances the probability that a 1-1.5 g subsample is representative of the
larger sample received. 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.
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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 DRPs. DRPs may consist of small pieces of the original radioactive
source and thus may have very high specific activity.
A4.1.6. When DRPs are present, this method isolates larger particles by passing
the sample through a disposable 30-mesh sieve 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 laboratory's safety manual for concerns of contamination
control and personal exposure monitoring.
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 and radiation dose monitoring.
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. Discrete Radioactive Particles (DRPs or hot particles)
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).
A5.3. Method-Specific Non-Radiological Hazards
A5.3.1. This method employs a hydraulic press and/or paint can shaker which
should be evaluated for any potential hazards associated with the crushing
process.
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A6. Equipment and supplies
A6.1. Aluminum foil loaf or casserole pans, disposable.
A6.2. Balance, top-loading, range to accommodate sample size encountered, readability
to ±1%.
A6.3. Butcher paper or equivalent.
A6.4. Drying oven, at 110±10 °C.
A6.5. Disposable wire cloth - nominal 48 mesh size (-300 [^m).
A6.6. Disposable or reusable sieves, U.S. Series No. 50 (300 [j,m or 48 mesh) and U.S.
Series No. 100 (150 [j,m or 100 mesh).
A6.7. Heavy ball peen hammer or equivalent
A6.8. Hydraulic press.
A6.9. Disposable scoop, scraper, tongue depressor or equivalent.
A6.10. Red Devil 5400 mechanical paint shaker, or equivalent.
A6.ll. Sieves, 10 mesh and 30 mesh
A6.12. Steel paint cans and lids (pint, quart, 2 quart, 1 gallon, as needed).
A6.13. 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
asphalt pieces, the size of the can, and the volume of asphalt processed.
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. Standard 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 (APSs) 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
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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 or materials come in contact with sample
materials to 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 asphalt 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: Asphalt samples typically do not contain large amounts of moisture. The
determination of moisture through drying can be problematic due to the difficulty of drying
to a constant weight with volatile organics present. Large chunks of asphalt will require
crushing prior to coning and quartering. The next step uses absorbent paper in a different
fashion than for the paper's normal use; it allows for a smooth division of the sample and
control of contamination.
A10.2.1. Spread a large piece of plastic backed absorbent paper, plastic side up
in a hood.
A10.2.2. If the asphalt sample is received with chunks that are too large to cone
and quarter, crush the larger pieces to manageable size using a
hydraulic press or hammer.
A10.2.2.1. Wrap asphalt pieces in butcher paper (or plastic bags) and
place in small disposable aluminum foil pan. Fold over or
place another aluminum foil pan on top of wrapped
asphalt sample.
A10.2.2.2. Crush sample between the aluminum foil pans using a
hydraulic press or heavy hammer.
A10.2.2.3. Break crushed pieces into smaller pieces for coning and
quartering. A hammer can be used to crush further, if
needed.
A10.2.2.4. Unwrap crushed asphalt and break apart into smaller
pieces for coning and quartering, then ball milling.
A10.2.3. If the sample volume is less than -450 mL, there is no benefit to coning
and quartering (Reference A16.1).
A10.2.3.1. Carefully pour the sample onto the paper.
A10.2.4. If the sample volume is greater than -450 mL, carefully pour the entire
sample into a cone onto the paper.
A10.2.5. The sample is split at least twice using the coning and quartering steps
that follow.
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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.
A10.2.5.1. Spread the material into a flat circular cake of asphalt
using a tongue depressor or other suitable disposable
implement. Divide the cake radially and return two
opposing quarters to the original sample container.
A10.2.5.2. Reshape the remaining two quarters into a smaller cone,
and repeat Step A10.2.5.1 until the total volume of the
remaining material is approximately 100-150 mL.
A10.2.6. Transfer the coned and quartered asphalt sample to a tared and labeled
1-pint paint can. If the initial total volume (Step A10.1.3) was less than
-450 mL, transfer the entire sample to a tared and labeled 1-quart paint
can.
A10.3. Place the can (without lid) in an oven at 110±10 °C and dry the asphalt to constant
mass.
Note: Asphalt samples may be dry enough such that heating prior to homogenizing the
sample is not required. Heating to a constant mass may be difficult due to the presence of
volatile organics.
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 two to five 1.5-2.5-centimeter (cm) stainless-steel or ceramic balls to the
can. Replace the lid and seal well.
A10.6. Shake the can and contents for -10 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 subsampling and subsequent
fusion or digestion processes.
A10.7. Following milling, a small fraction of residual larger particles may remain in the
sample.
Note: The following steps offer guidance that may be used if larger-particle DRPs are
encountered. The goal is to crush and mill and homogenize the asphalt samples in a way that
allows representative aliquants to be taken for analysis. This guidance may be modified as
needed with concurrence from the incident commander.
A10.7.1. 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 30 mesh
sieve and checked for radioactivity. DRPs are readily identified by their
very high specific activity which is detectable using hand-held survey
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equipment such as a thin-window G-M probe held within an inch of the
particles.
A10.7.1.1. 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.
A10.7.1.2. If the presence of DRPs is of no concern (no high
activities detected for specific particles), the larger
particles need not be included in subsequent subsamples
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 30 mesh sieve (disposable) prior to
further subsampling for subsequent analyses.
A10.8. Sample fines may be stored in, and aliquanted directly from, the container used
for pulverization, if the paint can ball mill approach was used.
A11. Calibration and Standardization
A11.1. 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
Note: Asphalt samples may be dry enough such that heating prior to homogenizing the sample is not
required. Heating to a constant mass may be difficult due to the presence of volatile organics.
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:
% Solids = Mdry Mfare x 100
M»rec
Where:
Mdry = mass of dry sample + labeled can + lid (g)
Mtare = tare mass of labeled can + lid (g)
Masrec = 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 Sample Equivalent = Mtotal_asrec x———
where:
Mtotai-as rec = total mass of sample, as received (g)
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A12.3. Results Reporting
A12.3.1. The result for percent solids and the approximate total mass of sample
as received should be reported for each result.
A13. Method Performance
A13.1. Expected turnaround time for these sample preparation steps is about 3 hours for
an individual sample and about 4 hours per batch.
A14. Pollution Prevention.
Not applicable.
A15. W aste Management
A15.1. All radioactive and other regulated wastes shall be handled according to
prevailing regulations.
A16. References
A16.1. EPA 2004. Multi-Agency Radiological Laboratory Analytical Protocols Manual
(MARLAP). Volumes 1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG
1576, NTIS PB2004-105421, July. Available here.
A16.2. 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.
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