EPA-600-R-12-635
www.epa.gov/narel
August 2012
Revision 0
Rapid Method for Radium in Soil Incorporating
the Fusion of Soil and Soil-Related Matrices with
the Radioanalytical Counting Method for
Environmental Remediation Following
Radiological Incidents
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Radiation and Indoor Air
National Air and Radiation Environmental Laboratory
Montgomery, AL 36115
Office of Research and Development
National Homeland Security Research Center
Cincinnati, OH 45268
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
Revision History
Revision 0 I Revision 0 I 08-31-2012
This report was prepared for the National Air and 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 I-
41 and 2-43, both managed by Dan Askren. Mention of trade names or specific applications does not
imply endorsement or acceptance by EPA.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
RAPID METHOD FOR RADiuwi-226 ANALYSES IN SOIL
INCORPORATING THE FUSION OF SOIL AND SOIL-RELATED MATRICES WITH THE
RADIOANALYTICAL COUNTING METHOD
1. Scope and Application
1.1. The method is applicable to the fusion of soil and soil related matrices (e.g.,
sediments, dry deposition samples, loam, etc), prior to the chemical separation of
226Ra. The native concentration of elements such as barium, calcium, and strontium
may be significant in soil samples. This method has been modified from that used in
a pure water matrix due to these elements potentially interfering with final
spectrometric measurements.
1.2. This is a general method for soil samples, dry paniculate deposition samples, and
sediments collected following a radiological or nuclear incident.
1.3. Alternative rapid methods exist for sodium carbonate fusion of americium,
plutonium, or isotopic uranium (see Reference 16.2), and radiostrontium (see
Reference 16.3) in soil matrices. These fusion methods lead into analyses using the
published rapid methods for radionuclides in water (see Reference 16.1).
1.4. The dissolution by fusion of soils, or related matrices, by this method is expected to
take approximately 2-3 hours per batch of 20 samples. This assumes the laboratory
starts with a representative, finely ground, 1-g aliquant of dried sample.1 The
relatively high silica content of most soil samples requires an initial HF digestion.
Following that, sample combustion at 600 °C is necessary for removal of any
organic matter prior to fusion, unless it has been established that the amount of
organic matter present will not interfere with the analytical separations.
1.5. Soil samples must be dried and ground to at least 50-100 mesh size prior to fusion.
A Rapid Technique for Milling and Homogenizing Soil Samples is included as
Appendix A to this method.
1.6. As this method is a gross pre-treatment 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.
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 Radioanalytical Laboratories Participating in Incident Response Activities
(see Reference 16.4), or the protocols published by a recognized standards
organization for method validation.
1.7.1. In the absence of project-specific guidance, measurement quality objectives
(MQOs) for soil samples may be based on the Analytical Action Levels
(AALs) and Required Method Uncertainties (Z/MR and ^MR) found in the
Radiological Sample Analysis Guide for Incident Response — Radionuclides
in Soil (see Reference 16.5).
1 The laboratory should have a separate method for achieving sub-sampling of the sample based on grinding, mixing
and sizing the sample to achieve aliquant uniformity.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
2. Summary of Method
2.1. The method is based on the complete fusion of a representative, finely ground 1-
gram aliquant of dried sample with no insoluble residue remaining after dissolution
of the fused melt in acid.
2.2. For media composed of organic soil matrices, the sample is dry-ashed at 600 °C in
an appropriate vessel prior to fusion.
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 (um range).
3.2. Multi-Agency Radiological Analytical Laboratory Protocol Manual (MARLAP; see
Reference 16.6).
3.3. The use of the term soil throughout this method is not intended to be limiting or
prescriptive, and the method described herein refers to all soil related materials such
as sand, humic/fulvic soils, peat, loam, sediment, etc. 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, plant roots,
etc.) are not generally considered to be part of a soil matrix. When consistent with DQOs, these should
be removed from the sample prior to drying. It is recommended that this be verified with incident
command before discarding any materials.
4.1. Soils with high silica content require initial hydrofluoric acid digestion, or either
additional fusing reagent and boric acid or a longer fusion melt during Step 11.11. A
laboratory-specific validation would also be needed for those other pretreatments.
4.2. Soil and soil-related matrices contain a wide variety of elements in the ppm and
higher concentration range. As much information regarding the elemental
composition of the sample should be obtained as possible. For example, some soils
may have native concentrations of uranium, 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., radium or 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.
4.3. Matrix blanks for these soil and soil-related 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 will serve as process
monitors for the fusion, and as potential monitors for cross contamination during
batch processing.
4.4. Samples with elevated activity or samples that require multiple analyses from a
single soil sample may need to be split after dissolution. In these cases the initial
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
digestate and the split fractions should be carefully measured to ensure that the
sample aliquant for analysis is accurately determined.
4.4.1. 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. The subsequent chemical separation methods for water samples (see the rapid
method for 226Ra in water in Reference 16.1), specify a sample size (in liters), which
is used in the associated calculation of activity, uncertainty, etc. When this fusion
method is employed and samples of a matrix other than water are analyzed, and/or
the sample size is given in units other than liters, consideration must be given to the
sample size and units in order to ensure accurate reporting of the sample activity and
other quality parameters. In the subsequent chemical separation methods, the
appropriate sample size and units should be substituted for the volume of water
sample, in liters, discussed in those methods.
4.5.1. 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 lieu of the water volume in all calculations, with the
final results reported in the units requested by the incident command, rather
than liters.
4.5.2. 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.
4.6. In the preparation of blank samples, LCSs and duplicates, care should be taken to
create these 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. Platinum crucibles are required to withstand the harsh conditions of the digestion
and fusion processes used in this method.
4.8.1. The laboratory must develop effective processes for cleaning crucibles. The
effectiveness of the cleaning process should be demonstrated through
measures such as measurements of fusion blanks.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
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.
4.8.3. If platinum crucibles are not available, an effective, alternate method is
available that uses zirconium crucibles. See Rapid Method for Sodium
Hydroxide Fusion of Concrete Matrices prior to Am, Pu, Sr, Ra, and U
Analyses (see Reference 16.7) and RapidRadiochemicalMethod'for Total
Radiostrontium (Sr-90) in Building Materials for Environmental
Remediation Following Radiological Incidents (see Reference 16.8).
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.
5.1.2. Refer to the laboratory 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 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. Soil media should be individually surveyed using a thickness of
the solid sample that is appropriate for detection of the
radionuclide decay particles.
5.2.2. The sample size initially dried and homogenized should be of adequate size
to conduct all required measurements but not too large as to cause a potential
for generating airborne contamination.
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. This procedure employs molten salts generated at high temperatures
(-1,000 °C) in an open flame. The operator should exercise extreme care
when using the burners and when handling the hot crucibles. Thermal
protection gloves and a face shield are recommended when performing this
part of the procedure. The entire fusion process should be carried out in a
laboratory fume hood.
6. Equipment and Supplies
NOTE: For samples with elevated activity concentrations of these radionuclides, labware should be used
only once due to potential for cross contamination unless the cleaning process is demonstrated to be
effective in removing residual contamination. The laboratory quality manual should provide guidance
for making these decisions.
6.1. Adjustable temperature laboratory hotplates.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
6.2. Balance, top loading or analytical, readout display of at least ± 0.01 g.
6.3. Beakers, 250 mL capacity.
6.4. Crucibles, platinum, minimum capacity, 50 mL.
6.5. Dispensing pipette, 10 mL delivery volume. Alternately, a bottle-top dispenser,
small volume graduated cylinder, or any other device for delivering nominal 10 mL
volumes of reagent into a beaker or disposable cup.
6.6. Fisher blast burner or Meeker burner.
NOTE: Ordinary Bunsen burners will not achieve the high temperatures needed for fusion.
6.7. Ring stand with ceramic triangle (optional).
6.8. Drying oven.
6.9. Programmable muffle furnace capable of reaching at least 600 °C
6.10. Teflon spatula or glass rod.
6.11. Tongs for handling crucibles, platinum tipped.
6.12. Ten (10) mL transfer pipette.
6.13. Tweezers or forceps.
NOTE: See Appendix A for a method for ball-milling and homogenization of soils.
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 dry uniformly ground sample from which to procure an aliquant.
6.15. Ultrasoni c b ath.
6.16. Plastic backed absorbent paper.
7. Reagents and Standards
NOTES: Unless otherwise indicated, all references to water should be understood to mean Type I
Reagent water (ASTM D1193; see Reference 16.9).
All reagents are American Chemical Society (ACS) grade or equivalent unless otherwise
specified.
7.1. Sodium carbonate, Na2CC>3, anhydrous. Note that anhydrous sodium carbonate
should be stored in a desiccator.
7.2. Potassium carbonate, K2CO3, anhydrous. Note that anhydrous potassium carbonate
should be stored in a desiccator.
7.3. Boric acid, H3BO3. Reagent should be stored in a desiccator to minimize and uptake
of moisture.
7.4. Hydrofluoric acid, concentrated (40%), HF.
7.5. Hydrochloric acid (6 M), HC1. Carefully add 500 mL of concentrated hydrochloric
acid to about 500 mL of water and then dilute to 1 L with water.
7.5.1. Hydrochloric acid, 2 M. Add 33 mL of 6 M HC1 to 67 mL of water.
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7.6. Manganous chloride, MnCl2*4H2O.
7.7. Sodium Hydroxide, 10 M. Slowly add 40 g of NaOH pellets to about 50 mL of
water. Add water to make up to 100 mL.
7.8. Hydrogen peroxide, 30%, H2O2. Commercially available.
7.9. Stripping Reagent. Add 2 mL of 30% H2O2 to 98 mL of 2 M HC1.
7.10. Dry flux mix. Dry each reagent separately at 105 °C to remove moisture. Mix equal
weights of sodium carbonate, potassium carbonate, and boric acid and store in a
desiccator.
7.11. Ammonium sulfate,
7.12. Diphonix resin
7.13. Ascorbic acid: (
7.14. Isopropanol and 20% (v to v) Isopropanol with water
7.15. Radioactive tracers/carriers (used as yield monitors) and spiking solutions. 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 for 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., neodymium added for
microprecipitation of plutonium or uranium), should be added where indicated.
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.
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 hydrofluoric acid digestion/fusion procedure (or prior to charring of
organic matter when applicable), unless there is good technical justification for
doing otherwise.
9.2. Batch quality control results shall be evaluated and meet applicable analytical
project 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's Quality Manual
and procedures shall be used to determine acceptable performance for this method.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
9.2.1. An exception to this 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 analytical protocol specifications. 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 reagent 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 provides assurance that the
laboratory's sample size reduction and sub-sampling processes are
reproducible.
9.4. This method was validated at an analytical action level of 5.0 pCi/g of 226Ra and a
required method uncertainty of 0.62 was calculated for this action level. During the
validation process a measurement uncertainty of 0.3 pCi/g or less was achieved for
method validation reference material spiked at and below 5.0 pCi/g. Above 5 pCi/g
the calculated relative required method uncertainty was 13%. During the validation
process a relative measurement uncertainty of 5.3% was achieved between 5 and 15
pCi/g.
10. Calibration and Standardization.
10.1. Set up, operate, calibrate and perform quality control for alpha spectrometry units in
accordance with the laboratory's quality manual and standard operating procedures
and consistent with ASTM Standard Practice D7282, Sections 7-13, 18, and 24 (see
Reference 16.10).
NOTE: The calibrated energy range for the alpha spectrometer for this method should be from
-3.5 to 10 MeV.
10.2. If 225Ra is separated and purified from 229Th for use as a tracer, the activity reference
date established during standardization of the tracer is used as the 225Ra activity
reference date (see Appendix A of "Radium-226 in Water: Rapid Method for High-
Concentration Samples, Revision 0.1, in Reference 16.1).
99Q™, 99S
10.3. When using Th containing an equilibrium concentration of Ra, the time of most
OOP
recent separation/purification of the Th standard solution must be known in order
to determine the extent of secular equilibrium between 229Th and its 225Ra progeny.
Verify the date of purification by examining the Certificate of Analysis, or other
applicable documentation, for the standard.
10.4. When using 229Th containing an equilibrium concentration of 225Ra, 225Ra is
separated from its 229Th parent as the solution passes through the Diphonix® column.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
ooc
This is the beginning of Ra decay and the date and time used for decay correction
of the tracer.
OOP
10.4.1. If the purification date of the Th is not documented, at least 100 days must
97Q
have elapsed between separation and use to ensure that Th, and its progeny
225Ra are in full secular equilibrium (i.e., >99%. See Table 17.3).
11. Procedure
11.1. In accordance with the DQOs and sample processing requirements stated in the
project plan documents remove extraneous materials from the soil using clean
forceps or tweezers.
11.2. Dry samples to constant weight in an oven at 105 °C.
11.3. Homogenize the sample so that a representative finely ground sample aliquant can
be removed.
11.4. Weigh 1-g aliquants into separate crucibles. Add an amount of tracer to each of the
sample aliquants in the batch.
11.5. For samples containing sufficient organic matter to cause concerns with the
subsequent fusion process, the samples should be further heated in a muffle furnace
with temperature programming (using temperature hold points to ensure sample
ignition does not occur) up to 600 °C to ensure combustion of all organic matter.
NOTE: Combustion of the organic matter in the sample can usually be accomplished over the
course of 1-2 hours for 1 gram samples of soil where the material is spread into a thin layer (up
to about 0.4 cm thick).
11.6. Add 15 mL of concentrated HF and evaporate to dryness on a hotplate at medium to
high heat (-300 °C). The evaporation should be complete in approximately 45
minutes.
11.7. Add about 3 g of dry flux mix (Section 7.10).
11.8. Warm the crucible slowly over the low flame of a Meeker or Fisher blast burner. The
initial heating may produce a vigorous reaction, which may last approximately 5
minutes. The crucible may be held over the flame with tongs or supported on a ring
stand with a ceramic triangle.
11.9. After the initial reaction has subsided, increase the heat gradually over 5 minutes
until the burner is at full flame.
11.10. Heat until the crucible glows bright red.
11.11. Continue heating over full flame for 5 minutes until no visible reaction is observed
and the melt is completely liquid and homogeneous.
11.12. Remove the crucible from the flame and swirl the contents so that the melt solidifies
on the sides of the crucible, approximately half-way up the sides. This will facilitate
the rapid dissolution of the cooled melt.
11.13. The crucible should be allowed to cool to the point so that addition of 6 M HC1 will
not create a violent reaction. Usually this is cool enough to touch.
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11.14. When the crucible is moderately cool carefully add approximately 10 mL of 6 M
HC1 by using a clean transfer pipette to wash the solid fusion cake down the inside
walls of the crucible. The reaction of the acid with the fused carbonate material may
be vigorous and care must be taken to avoid frothing the sample over the top of the
crucible. It may be necessary to place a lid on the crucible during the acid reaction to
avoid sample cross-contamination.
11.15. If necessary, heat the crucible gently on a hotplate and occasionally swirl the sample
to facilitate the dissolution of the fusion cake. Ensure that the entire fusion cake is
dissolved and that no solid material remains on the sides of the crucible.
11.16. If necessary, add additional 6 M HC1 in small (~ 1 mL) increments to facilitate the
complete dissolution of the fusion cake.
11.17. Transfer the dissolved sample to an appropriately sized digestion container, rinsing
the crucible with 6 M of HC1 to ensure a quantitative transfer of material. [See Step
12.2 for discussion of sample aliquanting at this point.]
11.18. Determine barium content of a small aliquant of the dissolved flux by ICP-AES. It
may be necessary to account for the aliquant removed when performing final
calculations.
11.19. Based on the barium content of the sample, add sufficient barium to the sample so
that the final mass of barium is not more than 90 jig.
11.19.1. Add 90 |ig of barium to the batch LCS and method blank.
11.20. Add 30 mg of Mn2+ to all samples.
11.21. Add a few drops of phenolphthalein and addlO M of NaOH until just pink.
11.22. Slowly add 0.1 mL to 0.2 mL increments of 30% hydrogen peroxide. The solution
will foam due to the oxidation of Mn2+ to black, insoluble MnO2.
11.23. Allow the sample to mix either on a rotary shaker or using a stirring bar for about 30
minutes.
11.24. Either centrifuge and discard supernatant solution or settle and decant the
supernatant solution. Then rinse the MnO2 precipitate with about 40 mL of ASTM
Type I water
11.25. Dissolve the precipitate in ~5 mL of the MnO2 stripping reagent, and bring to a final
volume of 10 mL with water.
11.26. Add 0.2 g of ascorbic acid to reduce any Fe+3 to Fe+2.
11.27. Actinium and thorium removal using Diphonix resin:
11.27.1. Prepare a Diphonix® resin column for each sample to be processed as
follows:
11.27.2. Slurry -1.0 gram Diphonix® resin per column in water.
11.27.3. Transfer the resin to the 0.8-cm ID. x 4-cm columns to obtain a uniform
resin bed of-1.4-1.6 mL (bed height -26-30 mm). A top column barrier
(e.g., frit, glass wool, beads) may be used to minimize turbulence that may
disrupt the resin bed when adding solution to the column
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11.27.4. Precondition the column by passing 20 mL of 2-M HC1 through the
column discarding the column effluent.
11.28. Place a clean 50-mL centrifuge tube under each Diphonix® column.
11.29. Swirl the solution retained in Step 11.27 to remove bubbles and carefully load onto
the column taking care to minimize disturbing the resin bed. Collect column
effluents in the 50-mL centrifuge tube. Allow the solution to flow by gravity.
11.30. When the load solution has stopped flowing (or is below the top of the resin bed),
rinse the column with two 5-mL volumes of 2 M of HC1. Collect the rinse solutions
in the same 50 mL centrifuge tube (the total volume will be approximately 20 mL).
11.31. Record the date and time of the last rinse (Step 11.31) as the date and time of
separation of radium from parent and progeny. This is also the beginning of
ingrowth of 225At (and 221Fr and 217At).
Notes: If purified 225Ra tracer is added to the sample (see Step 10.2 above and 226Ra in water
method Appendix A of Reference 16.1 [Revision 0.1]), the 225Ra activity was unsupported
before the tracer solution was added to the sample. The activity reference date and time
established during standardization of the 225Ra tracer is used as the reference date for the
225Ra solution.
If 225Ra at some degree of secular equilibrium with 229Th is added as tracer in the initial
step, the activity of 225Ra is dependent upon the total amount of time between the last
229Th purification and Step 11.31. The decay of 225Ra starts at Step 11.31.
The Diphonix® resin contains thorium, actinium and possibly other radionuclides present
in the sample and should be disposed of according to applicable laboratory procedures.
11.32. Barium sulfate micro-precipitation of 226Ra
11.32.1. Add -3.0 g of (NH4)2SO4 to the 20 mL of 2M HC1 solution collected
from the Diphonix® column in Steps 11.29 - 11.31. Mix gently to
completely dissolve the salt (dissolves readily).
11.32.2. Add 5.0 mL of isopropanol and mix gently (to avoid generating bubbles).
11.32.3. Place in an ultrasonic bath filled with cold tap water (ice may be added)
for at least 20 minutes.
11.32.4. Pre-wet a 0.1-micron filter using methanol or ethanol. Filter the
suspension through the filter using vacuum. The precipitate will not be
visually apparent.
11.32.5. Rinse the sample container and filter apparatus with three 2-mL portions
of 20% isopropanol solution to dissolve residual (NH4)2SO4. Allow each
rinse to completely pass through filter before adding the subsequent rinse.
11.32.6. Rinse the filter apparatus with about 2 mL of methanol or ethanol to
facilitate drying. Turn off vacuum.
11.32.7. Carefully remove the filter and place it face-side up in a Petri dish.
Carefully dry under a heating lamp for few minutes. Avoid excessive heat,
which may cause the filter to curl or shrink. Mount the dried filter on a
support appropriate for the counting system to be used.
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917
11.32.8. Store the filter for at least 24 hours to allow sufficient At (third progeny
of 225Ra) to ingrow into the sample test source allowing a measurement
uncertainty for the 217At of < -5%.
11.32.9. Count by alpha spectrometry. The count times should be adjusted to meet
the uncertainties and detection capabilities identified in Step 9.4.
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 RapidRadiochemicalMethodfor
Radium-226 in Water for Environmental Remediation Following Homeland Security
Events, Section 12 (Data Analysis and Calculations) (see Reference 16.1) with the
exception that the sample size is calculated as described below. The units would be
provided by the incident command, likely in either kilograms or grams, rather than
liters of water.
12.2. In cases where samples have elevated activity and multiple radionuclides are to be
analyzed, aliquants should be removed carefully, first measuring the mass or volume
of the entire final digestate. The mass or volume of the aliquants removed must also
be carefully measured to ensure that the sample aliquant size used for analysis is
accurately determined. The creation of multiple aliquants of a sample should be
thoroughly documented and reported in the case narrative.
For a single split the effective size of sample is calculated:
v.-v.D~
a s
Equation 1
Where:
Vs = original sample size, in the units designated by the incident command
(e.g., 1 g, etc.)
Ds = mass or volume of the entire final digestate, created in Step 11.3 of this
procedure (e.g., 100 g, 50 mL, etc.).
Da = mass or volume of the aliquant of digestate used for the individual
analyses, as described in the various parts of Step 11.18 of this procedure
(e.g., 25 g, 5.0 mL, etc.). Note that the values for Da must be in the same
units used in Ds.
Va = sample aliquant size, used for analysis, in the units designated by the
incident command (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.
12.2.1. 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 incident command.
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13. Method Performance
13.1. Method validation results should be archived by the laboratory.
13.2. Expected turnaround time per sample.
13.2.1. For representative, finely ground 1-g aliquant of dried sample where
combustion to remove organic^ is required, combustion of the sample and
the subsequent fusion should add approximately 5 hours per batch to the time
specified in the individual chemical separation methods.
13.2.2. In some cases it may not be necessary to perform combustion to remove
organic matter. For representative, finely ground 1-g aliquant of dried sample
where combustion to remove organics is not required, the fusion should add
approximately 2 hours per batch to the time specified in the individual
chemical separation methods.
NOTE: Turnaround times for the subsequent chemical separation methods are given in those
methods for batch preparations.
14. Pollution Prevention
With the exception of minute quantities of combustion products, 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 fume hood system.
15. Waste Management
15.1. Refer to the appropriate chemical separation methods for waste disposal information.
16. References
16.1. U.S. Environmental Protection Agency (EPA). 2010. RapidRadiochemicalMethods
for Selected Radionuclides in Water for Environmental Restoration Following
Homeland Security Events, Office of Air and Radiation, National Air and Radiation
Environmental Laboratory. EPA 402-R-10-001, February. Revision 0.1 of rapid
methods issued October 2011. Available at:
www.epa.gov/narel/incident guides.html.
16.2. U.S. Environmental Protection Agency (EPA). 2012. Rapid Method for Sodium
Carbonate Fusion of Soil and Soil-Related Matrices Prior to Americium, Plutonium,
and Uranium Analyses for Environmental Remediation Following Radiological
Incidents. Revision 0. Office of Air and Radiation, National Air and Radiation
Environmental Laboratory. Available at: www.epa.gov/narel/incident_guides.html.
16.3. U.S. Environmental Protection Agency (EPA). 2012. Rapid Method for Sodium
Carbonate Fusion of Soil and Soil-Related Matrices Prior to Strontium-90 Analyses
for Environmental Remediation Following Radiological Incidents. Revision 0.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
Office of Air and Radiation, National Air and Radiation Environmental Laboratory.
Available at: www.epa.gov/narel/incident_guides.html.
16.4. 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/incident_guides.html.
16.5. U.S. Environmental Protection Agency (EPA). 2012. Radiological 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 at:
www.epa.gov/narel/incident guides.html.
MARLAP. 2004. Multi-Agency Radiological Laboratory Analytical Protocols
Manual. Volumes 1-3. Washington, DC: EPA 402-B-04-001A-C, NUREG 1576,
NTIS PB2004-105421. July. Available atwww.epa.gov/radiation/marlap/links.html.
16.7. U.S. Environmental Protection Agency (EPA). 2012. "Rapid Method for Sodium
Hydroxide Fusion of Concrete Matrices Prior to Am, Pu, Sr, Ra, and U Analyses."
Revision 0. Office of Air and Radiation, National Air and Radiation Environmental
Laboratory. Available at: www.epa.gov/narel/incident guides.html.
16.8. U.S. Environmental Protection Agency (EPA). 2012. "RapidRadiochemicalMethod
for Total Radiostrontium (Sr-90) in Building Materials for Environmental
Remediation Following Radiological Incidents." Revision 0. Office of Air and
Radiation, National Air and Radiation Environmental Laboratory. Available at:
www.epa.gov/narel/incident_guides.html.
16.9. ASTM Dl 193, "Standard Specification for Reagent Water" ASTM Book of
Standards 11.01, current version, ASTM International, West Conshohocken, PA.
16.10. ASTM D7282 "Standard Practice for Set-up, Calibration, and Quality Control of
Instruments Used for Radioactivity Measurements," ASTM Book of Standards
11.02, current version, ASTM International, West Conshohocken, PA.
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17. Tables, Diagrams, Flow Charts, and Validation Data
17.1. Flow Chart for Separation
Steps 11.1-11.3
Remove detritus, add
tracer, dry,
homogenize and
aliquant
Step 11.4
Digest with HF and
evaporate to dryness
Step 11.5
Muffle combustion
needed?
Steps 11.7-11.14
Fusion using Na2CO3
Steps 11.15-11.20
Dissolve fused cake,
determine inherent
Ba concentration
and add Ba carrier
Steps 11.21-11.27
Ra isolation from
bulk contaminants
using MnO2
Steps 11.28-11.32
Removal of
interfering
radionuclide using
Diphonix
Step 11.33
Ra STS preparation
using
microprecipitation
ofBaSO4
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17.2. Tables [including major radiation emissions from all radionuclides separated]
Table 17.1 Alpha Particle Energies and Abundances of Importance
Energy
(MeV)
4.601
4.784
••:V'"459Sr.';;-
•••-r^msvw;
•):>r4^3.s.:..:;;>
•^4M$-m
?:V;»l>-;>v
''":;.%$$& ;•:;"
^!4$7!S£'^;
•Uv:;5<053-,7
5.434
5.449
5.489
5.540
5.580
5.607
5.609
5.637
5.682
5.685
5.716
5.724
5.732
5.732
5.747
Abundance
(%)
5.6
94.5
•' '/'• •••'•. •/•'I,- "C •- ••••-"•;
,•<;:/-:. -:M3-- ;:•:•:;•;
v;v;::;:9,rj-;;:r:
-^••'•W:' '"•••:•:'
:;'.o; -'56;2; •,;-;;••
:.;:;:vvio^:/-:^
;v-^:;&0^.;
v?:w£'^[?-i
r:;^;-6:C-;;:7
2.2
5.1
99.9
9.0
1.2
25.2
1.1
4.4
1.3
94.9
51.6
3.1
8.0
1.3
9.0
Nuclide
Ra-226
Ra-226
;:Xil;hr22^7
r>Th~229::;:;-
:;7T:h-23f.-;.
y,:.Tn^29--
v:-;T.Hi229:>-
;-:V:Tn-229:;:r
':-7Th-229:-;-;
•:;::;T;h>229v;^
Ra-223
Ra-224
Rn-222
Ra-223
Ac-225
Ra-223
Ac-225
Ac-225
Ac-225
Ra-224
Ra-223
Ac-225
Ac-225
Ac-225
Ra-223
- Analyte
Energy
(MeV)
5.791
5.793
5.830
5.869
6.002
6.051
6.090
6.126
6.243
6.278
6.288
6.341
6.425
6.553
6.623
6.778
6.819
7.067
7.386
7.450
7.687
8.376
8.525
11.660
Abundance
(%)
8.6
18.1
50.7
1.9
100.0
25.1
9.8
15.1
1.3
16.2
99.9
83.4
7.5
12.9
83.5
100.0
79.4
99.9
100.0
98.9
100.0
100.0
2.1
96.8
Nuclide
Ac-225
Ac-225
Ac-225
Bi-213
Po-218
Bi-212
Bi-212
Fr-221
Fr-221
Bi-211
Rn-220
Fr-221
Rn-219
Rn-219
Bi-211
Po-216
Rn-219
At-217
Po-215
Po-211
Po-214
Po-213
Po-212
Po-212
217At (3rd progeny of 225Ra tracer)
Th (Check region of interest [ROI] for indications
of inadequate clean-up)
Includes only alpha particles with abundance > 1%.
Reference: NUDAT'2.4, Radiation Decay National Nuclear Data Center, Brookhaven National
Laboratory; Available at: www.nndc.bnl.gov/nudat2/indx dec.jsp; Queried: November 11, 2007.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
17.3. Decay Scheme
a
164|js
22.2 y
p
226Ra Decay Scheme
Secular equilibrium is
established between 226Ra
and 222Rn in about 18 days.
1 h
3.1 min
a
27 min
1,600y
a
3.8 d
a
It takes about 4 hours for secular
equilibrium to be established
between 222Rn and 214Po after
fresh 222Rn is separated.
17.4. Ingrowth
1000
E
Q.
-a
Ac-225 In-Growth in Ra-225
200
400 600
Time, Hours
800 1000
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
E
Q.
•a
250
200 <>
150
100
Ra-225 In-Growth in Th-229
-Th-229, dpm
-Ra-225, dpm
100 120
Table 17.2 Ingrowth Factors for 217At in 225Ra
Time elapsed between
separation of Ra and
midpoint of count
in hours
Ingrowth Factor*
Time elapsed between
separation of Ra and
midpoint of count
in hours
Ingrowth Factor*
1
0.002881
72
0.1748
2
0.005748
96
0.2200
3
0.008602
120
0.2596
4
0.01144
144
0.2940
5
0.01427
192
0.3494
6
0.01708
240
0.3893
24
0.06542
360
0.4383
48
0.1235
480
0.4391
''ingrowth Factor represents the fraction of 'Ac activity at the midpoint of the sample count
relative to the 225Ra activity present at the date/time ofRa separation. These ingrowth factors
may be closely approximated (within a fraction of a percent) using the expression for At in Step
12.2.2.
Table 17.3 Ingrowth Factors for 225Ra in 229Th
Time elapsed between
purification of the 229Th
standard and date of Ra
separation
in days
Ingrowth Factor*
Time elapsed between
purification of the 229Th
standard and date of Ra
separation
in days
Ingrowth Factor*
1
0.04545
50
0.9023
5
0.2075
55
0.9226
10
0.3720
60
0.9387
12
0.4278
70
0.9615
15
0.5023
80
0.9758
20
0.6056
90
0.9848
25
0.6875
100
0.9905
27
0.7152
130
0.9976
30
0.7523
160
0.9994
40
0.8445
200
0.9999
Ingrowth Factor represents the fraction Ra activity/ Th activity at the time ofRa separation.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
Table 17.4 Decay Factors for Unsupported Ra
Time elapsed
between separation
of229Thand225Ra
in days
Decay Factor*
Time elapsed
between separation
of229Thand225Ra
in days
Decay Factor*
1
0.9545
50
0.09769
5
0.7925
55
0.07741
10
0.6280
60
0.06135
12
0.5722
70
0.03853
15
0.4977
80
0.02420
20
0.3944
90
0.01519
25
0.3125
100
0.00954
27
0.2848
130
0.00236
30
0.2477
160
0.00059
40
0.1555
200
0.00009
Decay Factor represents the fraction Ra activity remaining.
n.i
130 -
120 •
110 •
100 •
90 -
80 -
70 -
60 -
SO -
40 -
30 -
20 -
10 -
0 -
5. Spectrum of Ra and the progeny of the Ra tracer
B.
J
I
frT.
V
\
I
I-
2 Jt
e»
M
M
Ac-
iffc
W-ti*
ȣ
(
t!
t
(
S[j
1
1
(-.,
1
1
1
s
A,l
J
At-2
^
17
304S 3345 3645 4245 4S1G 4C45 5145 544s 574S
Energy (fceV)
6345 6345 72
This spectram is typical of the samples analyzed in this method. The baseline of the two 226Ra peaks is separated by
the 186 keV energy difference between them. The 217At peak is distinct and has a full width at half maximum
(FWHM) of about 55 keV. The range of FWHM for this peak during validation runs was 45 to 74 keV with the
majority of the peaks having a resolution of 50-60 keV.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
Appendix A:
Rapid Technique for Milling and Homogenizing Soil Samples
Al. Scope and Application
ALL The method describes one approach for the rapid, gross preparation of soil samples
to yield dried, 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 soil samples.
Al .2. This rapid milling method is designed to be used as a preparatory step for the
fusion of soils for Am, Pu, U, 90Sr, and 226Ra. It may also be applied to other
matrices whose physical form is amenable to pulverization in the ball mill. It is not
amenable to radionuclides that are volatile at 110 °C or below.
A1.3. The use of the term soil is not intended to be limiting or prescriptive. The method
described applies to soil-related materials such as sand, humic/fulvic soils, peat,
loam, sediment, etc.
Al .4. If the levels of activity in the sample are low enough to permit safe radiological
operations, up to 2 kg of soil can be processed.
A2. Summary of Method
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 vegetation, biota, or 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 soil (e.g., 500 mL).
A2.3. The entire sample as received is split by coning and quartering until -75-150 mL of
soil are available for subsequent processing. If less than -450 mL of soil are
received, the entire sample is processed.
A2.4. The soil is transferred to a paint can and dried. Percent solids are determined, if
required.
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 300 um.
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 drying and pulverization.
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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 (um range).
A3.2. Multi-Agency Radiological Analytical Laboratory Protocol (MARLAP) Manual
(see Reference 16.6).
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 (see Reference A16.3) for an approach for
homogenization and milling of larger soil samples.
A4.2. 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.
A4.3. 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.
A4.4. If the sample was collected near the epicenter of an 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
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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 size reduced to less than 50-100 mesh, these particles may
resist fusion or digestion of the solids into ionic form which can be subjected to
chemical separations.
A4.5. 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.
A4.6. 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.
A5.1.2. Refer to the laboratory chemical hygiene plan for general chemical
safety rules
A5.2. Radiological
A5.2.1. Refer to your radiation safety manual for direct 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 filter or smaller 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.
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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-mm diameter. The size
and number of grinding media used should be optimized to suit the types of sand or
soil, the size of the can, and the volume of soil processed.
A6.5. Wire cloth - nominal 48 mesh size (-300 um).
A6.6. 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 mechanical.
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
Project 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.
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
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 sample cross-contamination and concerns about adequate cleaning of
equipment.
A10.1. Estimate the total volume of sample, as received.
NOTES: 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.
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 0.1.1. Spread a large piece of plastic backed absorbent paper, plastic side up in
a hood.
A10.1.2. If the sample volume is less than -450 mL, there is no benefit to coning
and quartering.
A10.1.2.1. Carefully pour the sample onto the paper.
A10.1.2.2. Remove extraneous material, such as vegetation, biota, or
rocks or debris unless the project requires that such material
be processed as part of the sample. Continue with Step
A10.1.6.
A10.1.2.3. 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 vegetation, biota, or
rocks or debris unless the project requires that such material
be processed as part of the sample.
A10.1.3. 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
volatile components or percent solids are to be determined.
A10.1.4. 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.
See IUPAC Gold Book, Coning and Quartering in Analytical Chemistry, available at:
goldbook.iupac.org/C01265.html
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Rapid Method for 226Ra in Soil Incorporating the Fusion of Soil and Soil Related Matrices
A10.1.5. Reshape the remaining two quarters into a smaller cone, and repeat Step
A10.1.3 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 label
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
A10.1.6. Transfer the coned and quartered sample to a tared and labeled 1-pint
paint can. If the total volume was less than -450 mL, transfer the entire
sample to a tared and 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 may also be achieved operationally by
observing the time needed to ensure that 99% of all samples will obtain constant
mass.
A10.2. Place the can (without lid) in an oven at 110 ± 10 °C and dry the soil to constant
mass.
A10.3. Weigh the combined mass of the can, sample, and lid. If the percent solids are
required see Step A12.1 calculations.
A10.4. Add five 1.5-cm stainless-steel or ceramic balls or rods to the can. Replace the lid
and seal well.
A10.5. Shake the can and contents for 5-15 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.
A10.6. 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.
A10.7. Following milling, a small fraction of residual larger particles may remain in the
sample.
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 48 mesh
screen and checked for radioactivity. DRPs are readily identified by
their very high specific activity which is detectable using hand-held
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survey 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, 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 50
mesh screen (disposable) prior to further subsampling for
subsequent analyses.
A10.8. Sample fines may be stored in, and aliquanted directly from, the container used for
drying and pulverization.
All. Calibration and Standardization
Balances used shall be calibrated using National Institute of Standards and Technology
(NIST)-traceable weight 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:
% Solids = M(fay'Mtare x 100
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 as
follows:
% Solids
Dry SampleEquivalent = Mtotal.asrec x IQQ
Where:
Mtotai-as rec. = total mass of sample, as received (g)
A12.3. Results Reporting
The result for percent solids and the approximate total mass of sample as received
should generally be reported for each result.
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A13. 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.
A15. Waste Management.
All radioactive and other regulated wastes shall be handled according to prevailing
regulations.
A16. References
A16.1. A. D. McNaught and A. Wilkinson, Coning and Quartering in Analytical
Chemistry, IUPAC Compendium of Chemical Terminology, The Gold Book,
Second Edition, Blackwell Science, 1997 (online edition).
A16.2. ALS Environmental, Fort Collins, SOP 736.
A16.3. ASTM C 999-05, Standard Practice for Soil Sample Preparation for the
Determination of Radionuclides, Volume 12.01, ASTM, 2005.
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A17. Tables, Diagrams, and Flow Charts
A17.1. Homogenization
Steps A10.1.1-A10.1.2
Estimate Sample volume,
remove detritus
StepsA10.2-A10.3
Dry at 110 °C to constant
mass
StepAlO.1.3
Cone and quarter, transfer
aliquantto tared container
StepsA10.-A10.5
Add ceramic or steel balls
and mix
Steps 10.6-A10.7 Visual
inspection for homogeneity
and particle size
StepAlO.8
Aliquant sample and store
residual
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