EPA/600/R-11/181
www.epa.gov/narel
November 2011
Revision 0
Rapid Radiochemical Method for Phosphorus-32
in Water for Environmental Remediation
Following Homeland Security Events
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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Phosphorous-32 in Water: Rapid Method for High Activity Samples
Revision History
Revision 0 | Original release. | 11/17/2011
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 assignment I-
41, managed by David Carman and Dan Askren. Mention of trade names or specific applications does
not imply endorsement or acceptance by EPA.
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Phosphorous-32 in Water: Rapid Method for High Activity Samples
Rapid Radiochemical Method for Phosphorus-32 in Water for Environmental
Remediation Following Homeland Security Events
1. Scope and Application
1.1. The method will be applicable to water samples where radioactive contamination is
either from known or unknown origins. If any filtration of the sample is performed
prior to starting the analysis, those solids should be analyzed separately. The results
from the analysis of these solids should be reported separately (as a suspended activity
concentration for the water volume filtered), but identified with the filtrate results.
1.2. The method is specific for 32P in drinking water and other aqueous samples. 33P, another
long-lived isotope of phosphorous, may be present in the sample. However, since the
beta particle energy is insufficient to generate Cerenkov radiation, it will not interfere
with analysis for P by this method.
1.3. The method uses rapid radiochemical separation techniques for determining 32P in water
samples following a radiological or nuclear incident. Although the method can detect
concentrations of 32P on the same order of magnitude as methods used for the
measurement of gross beta concentration for the Safe Drinking Water Act (SDWA), the
method cannot be used for SDWA applications because no 32P-specific method has
been approved by EPA.
1.4. The method is capable of achieving a relative required method uncertainty for 32P of
13% at an analytical action level (corresponding to a 100-mrem dose rate for 50 years)
of 12,000 pCi/L with 100 mL of sample and a counting time less than 30 minutes (see
Steps 9.2 and 9.3). A larger sample size, followed by concentration and purification of
phosphate, and a longer counting time is necessary to achieve a comparable SDWA
detection level for gross beta concentration of 3 pCi/L (see Step 9.4). The Safe
Drinking Water Act Maximum Contaminant Level (MCL) for 32P is 30 pCi/L.
1.5. The sample turnaround time and throughput may vary based on additional project
MQOs, the time for analysis of the final sample test source, and initial sample volume.
The method must be validated prior to use following the protocols provided in Method
Validation Guide for Qualifying Methods Used by Radiological Laboratories
Participating in Incident Response Activities (See Reference 16.1).
1.6. The method is intended to be used for water samples that are similar in composition to
drinking water or surface water. The rapid 32P method was evaluated following the
guidance presented for "Level E Method Validation: Adapted or Newly Developed
Methods, Including Rapid Methods" in Method Validation Guide for Qualifying
Methods Used by Radiological Laboratories Participating in Incident Response
Activities (see Reference 16.1) and Chapter 6 of Multi-Agency Radiological Laboratory
Analytical Protocols Manual (MARLAP 2004, Reference 16.2). The matrix used for
the determination of 32P was drinking water from Atlanta, GA.
^9
1.7. The method is applicable to the determination of soluble P. The method is not
applicable to the determination of 32P in highly insoluble particulate matter possibly
present in water samples contaminated as a result of a radiological dispersion device
(RDD) event. The source of such materials may be brachytherapy sources encased in a
Ti-Ni casing. The proprietary nature of the chemical form of these sources makes it
difficult to establish a chemical analysis method. Suffice it to say that the acid digestion
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Phosphorous-32 in Water: Rapid Method for High Activity Samples
steps used in this method would be insufficient to dissolve such sources. This also
means that they would not be available for intake and accumulation in the body. For
this reason, the water sample is filtered first. The filtered residue should be retained for
subsequent analysis.
2. Summary of Method
2.1. A 100 mL water sample is filtered and phosphate carrier is added. The solution is passed
through a cation exchange resin and then a Diphonix® resin to remove interferences
from cation radionuclides. The eluent is treated with a mixture of 10 mL of 30 % H2O2
and 10 mL of concentrated nitric acid, reduced in volume, by heating, to approximately
2 to 5 mL, and quantitatively transferred to a LSC vial for counting. The Cerenkov
photons from the 32P beta (1710 keV, Emax) decay are detected using a calibrated liquid
scintillation counter (LSC). Following counting of the sample, an aliquant of the final
solution is used for yield determination by the inductively coupled plasma-atomic
emission spectrometry (ICP-AES) method.
3. Definitions, Abbreviations, and Acronyms
3.1. Analytical Protocol Specifications (APS). The output of a directed planning process that
contains the project's analytical data needs and requirements in an organized, concise
form.
3.2. Analytical Action Level (AAL). The term "analytical action level" is used to denote the
value of a quantity that will cause the decisionmaker to choose one of the alternative
actions.
3.3. Analytical Decision Level (ADL). The analytical decision level refers to the value that is
less than the AAL and is based on the acceptable error rate and the required method
uncertainty.
3.4. Discrete Radioactive Particles (DRPs or Hot Particles). Paniculate matter in a sample of
any matrix where a high concentration of radioactive material is contained in a tiny
particle (diameter is in the micro-meter range).
3.5. Figure of Merit (FOM). The figure of merit is a measure of the response to the analyte
by the instrument relative to the background. The FOM is the square of the detector
efficiency divided by the background count rate, both measured in the same region of
the spectrum.
3.6. Liquid Scintillation Counter or Counting (LSC). A beta spectrometer used to measure
Cerenkov radiations.
3.7. Multi-Agency Radiological Laboratory Analytical Protocols Manual (see Reference
16.2).
3.8. Measurement Quality Objective (MQO). MQOs are the analytical data requirements of
the data quality objectives and are either project or program specific. They can be
quantitative or qualitative. MQOs serve as measurement performance criteria or
objectives of the analytical process.
3.9. Radiological Dispersal Device (ROD), i.e., a "dirty bomb." This is an unconventional
weapon constructed to distribute radioactive material(s) into the environment either by
incorporating them into a conventional bomb or by using sprays, canisters, or manual
dispersal.
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3.10. Region of interest (ROI). The region of interest is that part of the spectrum for a
particular analyte or group of analytes where it is expected that the instrument will have
the most analytically favorable response. The ROI is user selected, often by using the
FOM calculation for different regions of the spectrum.
3.11. Required Method Uncertainty (MMR). The required method uncertainty is a target value
for the individual measurement uncertainties and is an estimate of uncertainty (of
measurement) before the sample is actually measured. The required method uncertainty
is applicable at or below an AAL.
3.12. Required Relative Method Uncertainty ($JMR). The required relative method uncertainty
is the MMR divided by the AAL and typically expressed as a percentage. It is applicable
above the AAL.
3.13. Sample Test Source (STS). This is the final form of the sample that is used for nuclear
counting. This form is usually specific for the nuclear counting technique used in the
method, such as a solid deposited on a filter for alpha spectrometry analysis.
4. Interferences
4.1. Radiological: Cerenkov counting measures photons generated by high energy beta
particles passing through the final test solution regardless of the radionuclide. The
threshold beta particle energy that can produce Cerenkov radiation with a counting
1 "29
efficiency of-6% is ~ 900 keV. Therefore, radionuclides other than P in the final
test sample solution having maximum beta emissions greater than 900 keV would
likely cause measurable interferences and bias results high. Below 900 keV, the
efficiency for Cerenkov counting decreases significantly. Table 17.1 lists some other
radionuclides that have sufficient high-energy beta emissions to be counted efficiently
by Cerenkov counting. This method provides a technique for the chemical purification
of phosphorous from these other potential radionuclides (e.g., fission products, 40K and
decay products of the natural occurring series) having sufficient beta energies to
produce Cerenkov radiations. Although it is unlikely that these radionuclides would
accompany 32P in a ROD, it is important that the method discriminate against them in
the final sample test source. Radiological interferences in the final sample test source
can be evaluated by counting the test source solution approximately 7 days from the
first count, and also by examining the energy distribution in the liquid scintillation
spectrum. The second count should produce a net count rate that is ~ 71% of the count
rate of the first test source measurement. Inferences also may be detected by examining
the energy distribution in the individual sample spectra and comparing it to the
expected, interference-free spectrum.
4.2. Non-Radiological: High levels of phosphates (>0.1 mg/L) in the water are accounted for
by the relative yielding technique used in this rapid method. If suspended solids are
observed or known to exist in the sample, the sample should be filtered through a 0.45-
um filter before proceeding with the method.
5. Safety
5.1. General
1 See Section 4.5.1 of NCRP Report No. 58, reference 16.7). A state-of-the art liquid scintillation counter may have
a better response to the Cerenkov radiation and provide higher detector efficiencies than those stated in the
reference.
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5.1.1. Refer to your 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. Hot Particles (DRPs)
5.2.1.1. Hot particles will be small, on the order of 1 mm or less. Typically,
DRPs are not evenly distributed in the media and their radiation
emissions are not uniform in all directions (anisotropic). Filtration
using a 0.45-um (or finer) filter will minimize the presence of these
particles.
5.2.1.2. 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, causing contamination.
5.2.1.3. Filter media should be individually surveyed for the presence of these
particles and this information should be reported with the final sample
results.
5.2.2. For samples with detectable activity concentrations of this radionuclide, labware
should be used only once due to potential for cross contamination.
5.3. Procedure-Specific Non-Radiological Hazards
• None
6. Equipment and Supplies
6.1. Analytical balance with a 0.001-g readability or better.
6.2. Toploader balance with a 0.1-g readability
6.3. Beakers, Pyrex® - 250, 400 mL
6.4. Hot plate, or other suitable device for reducing sample volume
6.5. Glass stirring rods
6.6. Graduated cylinders - 25, 50, 100, 250, 1,000 mL
6.7. Pipettes, volumetric / automatic: assorted volumes down to the microliter range.
6.8. Scintillation vials - 22 mL glass
NOTE: It has been demonstrated that plastic vials yield a higher efficiency for Cerenkov counting
than do glass vials.
6.9. Volumetric flasks - 25, 100, 200, 500, 1,000 mL.
6.10. Detector capable of measuring Cerenkov radiation - Liquid scintillation counter
6.11. Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES)
7. Reagents and Standards
NOTES: All reagents are American Chemical Society (ACS) reagent grade or equivalent unless otherwise
specified.
Unless otherwise indicated, all references to laboratory water should be understood to mean
ASTM D1193 Type I Reagent water (see Reference 16.3).
7.1. Cation exchange resin: DOWEX 50WX8 50-100 mesh, lOmL
7.2. Diphonix® resin (Eichrom): 100-200 mesh, 2.0 mL
7.3. Hydrogen peroxide (H2O2): (30%)
7.4. Demineralized water (DM)
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7.5. Carrier solution: Commercially available TCP standard for phosphorus diluted tol.OO
mg/mL P, or an approximate 10 mg/mL P solution prepared from Na3PO4»12H2O
standardized using the ICP-AES and diluted to 1.00 mg/mL P.
7.6. Nitric acid (HNOs): concentrated (16 M). Note: HNOs can degrade forming colored
contaminants (nitric oxides) which will interfere with Cerenkov counting. A new bottle
of HNOs free of color contaminants should be used.
7.6.1. Nitric acid (HNO3): 2 M; dilute 250 mL of concentrated HNO3 to 500 mL with
DM. Cool and dilute to 1,000 mL with DM.
8. Sample Collection, Preservation, and Storage
8.1. Collect a 1 liter sample in the field in a suitable container.
8.2. No sample preservation is required if sample is delivered to the laboratory within 3 days
of sampling date/time.
8.3. If the dissolved concentration of 32P is sought, the insoluble fraction must be removed by
filtration before preserving with acid.
8.4. If the sample is to be held for more than 3 days, concentrated HNOs shall be added to
achieve a pH < 2.
9. Quality Control
9.1. Batch quality control results shall be evaluated and meet applicable analytical protocol
specifications (APS) prior to release of unqualified data. In the absence of project-
defined APS or a project-specific quality assurance project plan (QAPP), the quality
control sample acceptance criteria defined in the laboratory quality manual and
procedures shall be used to determine acceptable performance for this method.
9.1.1. A laboratory control sample (LCS) shall be run with each batch of samples. The
concentration of the LCS shall be at or near the action level or level of interest
for the project.
9.1.2. One method blank shall be run with each batch of samples. The laboratory
blank should consist of laboratory water.
9.1.3. One laboratory duplicate shall be run with each batch of samples. The
laboratory duplicate is prepared by removing an aliquant from the original
sample container.
9.1.4. A matrix spike sample may be included as a batch quality control sample if
there is concern that matrix interferences may compromise chemical yield
measurements or overall data quality.
9.2. This method is capable of achieving a WMR of 150 pCi/L at or below an action level of
12,000 pCi/L.
9.3. This method is capable of achieving a ^MR 13% above 12,000 pCi/L. This may be
adjusted if the event specific MQOs are different.
9.4. This method is capable of achieving a required minimum detectable concentration
(MDC) of 3 pCi/L, provided that a minimum sample size of 500 mL is used and a count
time of at least 100 min is performed.
10. Calibration and Standardization
10.1. Initially set up the liquid scintillation spectrometer according to the manufacturer's
recommendations. The energy range of the spectrometry system should be capable of
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measuring in the region of interest (ROI) between 30 and 2,000 keV. Go to Step 10.3 to
establish the 32P ROI energy window that will be used to analyze 15-mL samples of a
2-M HNOs sample test source.
10.2. Conduct a final set up of the Liquid Scintillation Spectrometer for use to count samples
according to ASTM Standard Practice D7282, Section 9.4, "Liquid Scintillation
Counting Initial Instrument Set-up" (see Reference 16.5). Continuing Instrument
Quality Control Testing shall be performed according to ASTM Standard Practice
D7282, Section 25, Quality Control for the Liquid Scintillation Counter
10.3. Liquid Scintillation Counter Region-of-Interest Setup
10.3.1. The normal photomultiplier high voltage and amplifier gain settings used for
liquid scintillation counting (LSC) are satisfactory for Cerenkov counting. In
modern LS counters, the beta/Cerenkov radiation interactions in the test
sample generate photons detected by photomultiplier tubes (PMT). The PMT
in turn converts the detected photon energy voltage pulse which is amplified
and transferred to an analysis component of the counter. The voltage pulses
are separated by voltage height and digitally converted into an energy
spectrum through the use of a multichannel analyzer. The resulting energy
spectrum is divided into energy channels; the number of energy channels
covers the maximum beta particle or Cerenkov energy of interest (e.g., 4000
channels for 0 to 2,000 keV). For most applications, a ROI of the spectrum is
selected for a given radionuclide. Because of the relatively lower number of
photons generated and the lower photon-to-electron generation ratio compared
to LSC, the maximum beta energy needed for most practical Cerenkov
counting is about 1,000 keV, although radionuclides having lower maximum
beta energies can be measured.2 The Cerenkov counting efficiency for 32P
(Pmax = 1710 keV) is expected to be ~ 55%.
10.3.2. In a similar manner for LSC instrument set up, the ROI to be used for the
17
qualitative and quantitative determination of a P must be established prior to
instrument calibration and radionuclide quantification. The figure of merit
(FOM; efficiency2/background) concept shall be used to determine the most
advantageous 32P ROI. Once established, the ROI must be maintained during
on
the operation of instrument. A quality control chart using a Sr/Y source
should be used to ensure the ROI counting efficiency of the instrument has not
changed and the 32P ROI has not shifted.
10.3.3. The same LSC setting, LS vial type, sample volume, and acidic concentration
must be maintained during the establishment of the ROI and instrument
17
calibrations for P and instrument background.
10.3.4. The volume to the shoulder of the LSC vial is very reproducible. Using this as
a volumetric measure for the standards and samples saves time, sample
handling, and reduces potential for cross-contamination. Each laboratory
should measure this volume gravimetrically on their own. Typically, this
measurement shows a variability of less than 2%.
See Section 4.5.1 of NCRP Report No. 58, Reference 16.7. Radionuclides with lower beta maximum energies can
be measured, but efficiencies are quite low.
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10.3.5. Set the lower level discriminator of the LSC instrument to eliminate excessive
noise signals that give rise to low-energy counts. This setting will vary
depending on the instrument manufacturer.
10.4. 32P Region of Interest Determination
10.4.1. Count a 32P background vial containing 15.0 mL of 2 M HNO3 for 400
minutes. Label the vial and spectrum as 32PeKG and electronically save the
spectrum.
10.4.2. Use the 32P spectrum generated from the LSC Calibration (Step 10.3.2), set
the upper ROI channel to the end point channel of the 32P energy distribution,
32PEPC- Sum the number of counts from channel 10 to 32PEpc and divide by the
19
counting time. Note this as Pgcpmi •
10.4.3. Using the 32PeKG spectrum from the background sample vial, sum the number
of counts from channel 10 to 32PEPc and divide by the counting time. Note this
32n
as -TBKGcpml
10.4.4. Calculate the relative FOM value as:
32P _ 32p f/32p
gcpm; 1BKGcpm1/ / 1 BKGcpmj
Record this as the 32P mu value.
10.4.5. In a stepwise manner, gradually increase the lower channel included in the
19 19
ROI and sum the counts in a new ROI (e.g., channel 20 to PEPC) for the P
19 19 19 19
and PBKG spectra. Calculate P gcpni2, PBKGcpm2 and PpoM2- Continue
19
decreasing the ROI by incrementing the lower channel by 10 and calculate P
cpmi; 32PBKGcPmi and 32PFOM; values.
19
10.4.6. Review the PFOM values and select the ROI with the highest FOM value.
19
Record the ROI as the P ROI and use this window when calibrating the unit
19
for P detector efficiency as provided in Equation 1 .
10.5. 32P Region-of-Interest Counting Efficiency
10.5.1. Using the 32PBKG spectrum obtained in Step 10.4.1, calculate the background
count rate in the 32PRoi.
10.5.2. Prepare a calibration source by adding an appropriate amount of traceable 32P
concentration (at least 1,000 dpm) in a 5 mL solution of 8 M HNOs. Bring the
final solution volume to 15.0 mL with DM water. Note the reference time and
date of preparation and reference concentration (dpm) in the sample.
10.5.3. Count the 2P vial to obtain at least 10,000 counts in the same ROI energy
window optimized for 32P as determined in Step 10.4.6.
10.5.4. Calculate the 32P ROI fractional detection efficiency using the following
equations:
e__(R,-R^DC
ACxVxDF ( '
where
DF = Q-*™^-V 3
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DC= p-?° (4)
(l-e-V-^))
s = detection efficiency for 32P
19
Rs = gross P ROI count rate (cpm) for the working calibration source
Rb = count rate (cpm) of the background subtraction sample in the 32P
ROI
AC = concentration (dpm/volume or mass) of the 32P standard solution as
of its reference date
V = amount (volume or mass) of the standard solution added
DF = correction factor for decay of the standard from its reference date
through the measurement of the vial
DC = correction factor for decay during counting
Ap.32 = decay constant for 32P, 3.375x 1CT5 min"1
to = reference date and time for the 32P standard
t\ = date and time of the start of the Cerenkov counting measurement for
19
the P standard
tc = counting time in minutes
11. Procedure
11.1. Water Sample Preparation
11.1.1. As required, filter enough sample volume through a 0.45-um filter to provide
at least 200 mL for radiochemical analysis and sufficient volume for ICP-AES
analysis.
NOTES: A volume of at least 500 mL will be necessary to achieve a detection limit of 3
pCi/L. If the 3 pCi/L LLD is to be achieved in subsequent steps:
A sample volume of 500 mL should be used.
All additions of chemical volumes should be scaled up by a factor of 5.
11.1.2. Transfer 150 mL of the filtered sample to an appropriate container.
11.1.3. If not acidified in the field, add sufficient concentrated HNOs to the sample to
reach a pH of less than 2.0. This usually requires about 0.3 mL of HNOs per
150 mL of sample.
11.1.4. Add 1.0 mL of the 1.00 mg/mL phosphorous carrier solution to the beaker and
swirl to mix.
11.1.5. Use an aliquant of the sample to determine the phosphorus concentration in
|ig/mL by ICP-AES. Record the concentration as Pconcr
11.1.6. Prepare a 10-mL cation exchange column in tandem with a 2 mL Diphonix®
column.
11.1.7. Pass about 20 mL of the sample solution through the tandem column
arrangement and discard the eluate.
NOTES: This volume is sufficient to equilibrate the columns with the sample solution.
The flow rate through the columns may be controlled using devices such as a
vacuum box or peristaltic pump. The flow rate should not exceed about 5
mL/minute.
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11.1.8. Pass the remaining sample solution through the columns and collect the eluate
in an appropriate container.
11.1.9. Measure a known volume (approximately 100 mL) of the sample which has
passed through the columns into a 250 mL beaker for performing evaporation
and digestion on a hot plate.
11.1.10. Add 10 mL of 30% H2O2 and 10 mL of concentrated nitric acid.
11.1.11. Bring the solution to near boiling and reduce the volume to between 2 and 5
mL.
1 1.2. Preparation of the sample test source
1 1 .2. 1 . Transfer the solution to a liquid scintillation vial and rinse the beaker three
times with 5-mL aliquants of 2-M nitric acid.
1 1 .2.2. Bring the level in the liquid scintillation vial to the shoulder of the vial (refer
to Step 10.3.4), cap, and invert several times to mix.
1 1.2.3. Count the liquid scintillation vial for a period of time sufficient to achieve a
WMnof 150pCi/L.
11.2.4. After counting the sample test source, remove an aliquant and determine the
phosphorous concentration (|ig/mL) by ICP-AES. Record the concentration as
12. Data Analysis and Calculations
12.1. Equation for determination of final result, combined standard uncertainty, and chemical
yield (if requested):
The activity concentration of an analyte and its combined standard uncertainty are
calculated using the following equations:
12.1.1. The 32P activity concentration (AC) is calculated as follows:
where:
AC= .
2.22xsxYxVxDF
(7)
(l-e^p-32(y)
and where:
R& = gross count rate for the sample (cpm) in 32P ROI
Rb = background count rate (cpm) 32P ROI
s = efficiency of the detector for 32P ROI
7 = fractional chemical yield for phosphorous
V = volume of the sample aliquant (L)
DF = correction factor for decay of the sample from its
reference date until the start of the 32P count
DC = correction factor for decay during counting
Ap.32 = decay constant for 32P, 3.375x 10~5 min"1
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to = reference date and time for the sample
t\ = date and start time of counting the sample
Note: the differential time t\ - to must be in minutes
tc = counting time in minutes
Note: The elapsed time between the sample count and the reference date must be
calculated using the same time units as the decay constant
12. 1 .2. The standard counting uncertainty of the phosphorous activity concentration,
wcc, is calculated as follows:
*. tb
cc 2.22 xsxYxVxDF
where:
4 = duration of the sample count (min), and
tb = duration of the background subtraction count (min).
12.1.3. The combined standard uncertainty (CSU) for the 32P activity concentration,
uc(ACp-32)-, is calculated as follows:
uc(ACP.32) = Ju2c + AC2 x !—^- + -
\ I £ 1 y J
where:
w(Y) = standard uncertainty of fractional chemical yield for phosphorous,
z/(V) = standard uncertainty of the volume of the sample aliquant (L), and
u(s) = standard uncertainty of the 32P ROI detector efficiency, s.
12.1.4. If the critical level concentration (Sc) or the minimum detectable
concentration (MDC) are requested (at an error rate of 5%), they can be
calculated using the following equations:3
0.4x --1 +0.677x 1 + - +1.645x
t x2.22xsxYxVxDF
:DC
(10)
3 The formulations for the critical level and minimum detectable concentration are based on the Stapleton
Approximation as recommended in MARLAP Sections 20A.2.2, Equation 20.54, and 20A.3.2, Equation 20.74,
respectively. The formulations presented assume a = 0.05, /? = 0.05 (with zi_a = Zj.p = 1.645), and d = 0.4.
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MDC =
2.71x1 1 + -?- | + 3.29x |^s x 1 + -
:DC
t x2.22xsxYxVxDF
(11)
12.2. Chemical Yield for Phosphorous
12.2.1. Calculate the chemical yield for phosphorous using the information gathered
in Steps 11.1.5 and 11.2.4.
The chemical yield of the carrier (7p) and its standard uncertainty u(Yp) can
be calculated using the following equations:
YP = y- (12)
where:
PI = (Pconcj in |ig/mL - refer to Step 11.1.5) x (sample volume used
in procedure in mL - refer to Step 11.1.9)
NOTE: Pt is the mass of P (jig) prior to performing procedure
PY = (Pconc2 in |ig/mL - refer to Step 11.2.4) x (volume of solution in
LCS vial in mL - refer to Step 10.3.4)
NOTES: Pt is the mass of P (fig) added as carrier
PY is the mass of P (fig) recovered after completing procedure.
and:
w(7p)~0.02 (is)
Because the yield determination is a relative comparison using the same ICP-AES
instrument, the uncertainty budget is related to the precision of the measurements, which is
estimated at 2% (assumes that all volumetric dilutions are much less that 2% and thus
contribute negligibly).
12.3. Results Reporting
12.3.1. The following items should be reported for each result: sample ID, volume of
sample used, carrier yield and its uncertainty, and Cerenkov counting efficiency
and its uncertainty.
12.3.2. The following items should be reported for each result:
12.3.2.1. Result in scientific notation ± combined standard uncertainty, critical
level, and MDC.
12.3.2.2. If solid material was filtered from the solution and analyzed
separately, the results of that analysis should be reported separately as
pCi/L of the original volume from which the solids were filtered if no
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other guidance is provided on reporting of results for the solids. For
example:
32P for Sample 12-1-99:
Filtrate Result: 12.8 ± 1.5 pCi/L
Filtered Residue Result: 2.5 ± 0.3 pCi/L
13. Method Performance
13.1. Method validation results are to be reported as an attachment.
13.1.1. Expected turnaround time per batch of 14 samples plus QC, assuming
microprecipitations for the whole batch are performed simultaneously:
13.1.1.1. For an analysis of a 100-mL sample aliquant, sample preparation, ion
exchange, digestion and evaporation should take ~ 5.5 h.
13.1.1.2. Final test source sample preparation for Cerenkov counting takes
-Sminutes.
13.1.2. A 100 minute counting time is sufficient to meet the MQOs listed in 9.2 and
9.4, assuming detector efficiency of- 0.35 and chemical yield of at least 0.9.
Longer counting time may be necessary to meet these MQOs if the yield is
lower.
13.1.3. Data should be ready for reduction between 8.5 and 10.5 h after beginning of
analysis.
14. Pollution Prevention: This method utilizes a Diphonix® resin (-10 mL) and a cation resin
(-10 mL). The removal of uranium, thorium, and TRU elements using the extraction column
results in the elimination of solvent extraction and other multiple step precipitation and ion
exchange techniques.
15. Waste Management
15.1. Types of waste generated per sample analyzed
15.1.1. Two mL of Diphonix® resin and 10 mL of cation exchange resins are generated
per sample. If a TRU column is used to remove transuranics, this is -2 mL.
15.1.2. Approximately 20 mL of acidic waste from the final sample tests source are
generated
15.1.3. Unless processed further, the TRU resin may contain isotopes of uranium,
neptunium, and thorium, if any of these were present in the sample originally.
15.2. Evaluate all waste streams according to disposal requirements by applicable
regulations.
16. References
16.1. 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 and
www.epa.gov/erln/radiation.html.
16.2. Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP).
2004. EPA 402-B-1304 04-001 A, July. Volume I, Chapters 6, 7, 20, Glossary;
11/17/2011 12 Revision 0
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Phosphorous-32 in Water: Rapid Method for High Activity Samples
Volume II and Volume III, Appendix G. Available at:
www.epa.gov/radiation/marlap/links.html.
16.3. ASTM Dl 193, "Standard Specification for Reagent Water" ASTM Book of
Standards 11.01, current version, ASTM International, West Conshohocken, PA.
Available at: www.astm.org/Standards/Dl 193.htm.
16.4. National Council on Radiation Protection and Measurements (NCRP). 1985. Report
No. 58, A Handbook of Radioactivity Measurements Procedures., Second Edition.
Available from www.ncrponline.org/Publications/Publications.html.
16.5. 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. Available at:
www.astm.org/Standards/D7282.htm.
16.6. Colle, R. 1999. "Chemical Digestion and Radionuclidic Assay of TiNi-Encapsulated
32P Intravascular Brachytherapy Sources" Applied Radiation and Isotopes, 50, 811-
833.
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Phosphorous-32 in Water: Rapid Method for High Activity Samples
17. Tables, Diagrams, Flow Charts, and Validation Data
17.1. Table 17.1, Beta Particle Energy and Abundance
Including major radiation emissions from all radionuclides separated.
Radionuclide
32p
33p
Half-Life
(days)
14.262
25.34
>,
(min"1)
3.374xlO~5
1.899xlO~5
Abundance
1.00
1.00
Energy (keV)
Maximum
Average
1710
695
249
76.4
Potential Radiological Interferences
90Sr(90Y)
89Sr
106Ru (106Rh)
140Ba(140La)
4oK
137Cs
124Sb
110mAg
l.OSxlO4
50.5
373
12.75
4.55x10"
1.103xl04
60.2
250
4.58xlO~8
9.53xlO~6
1.29xlO~6
3.77xlO~5
1.06xlO~15
4.38xlO~8
8.0x10^
1.93xlO~6
1.00
1.00
0.79
0.20
0.89
0.053
0.232
0.0129
2280
934
1495
584
3541
1508
1679
630
1311
560
1176
416
2302
918
2892
1199
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Phosphorous-32 in Water: Rapid Method for High Activity Samples
17.2. Spectra
17.2.1. Spectrum4 of Mixture of 32P and 33P
32p
° 2345 1Q1 2343 1Q2 £341 \ Q3 2
E/keV
17.2.2. Spectrum of Processed Sample
Total Counts vs. Channel
3000
2500
20CO
» 1500 ffl
I
o
1000
500
:15-'. ,: I 20
:.30- '
-500
Channel #
4 From "Chemical Digestion and Radionuclidic Assay of TiNi-Encapsulated 32P Intravascular Brachytherapy
Sources," Reference 16.10.
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15
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Phosphorous-32 in Water: Rapid Method for High Activity Samples
17.3. Decay Scheme
100 %
Ep max = 249 keV
100 %
ER max= 1710 keV
32S
Stable
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Validation of Rapid Radiochemical Method for Americium-241 on Air Filters
17.4. Flow Chart for Separation with Timeline
Sample preparation (Steps 11.1.1-11.1.3)
Filter, acidify, and aliquant for sample and native
phosphorous analysis
(
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