-------
fully opened without a significant amount of bubbling, the bubbler
is essentially at atmospheric pressure.again.
8.11 Open the outlet stopcock very slightly and allow bubbling to
proceed at a rate, determined by experience, such that 15 to 20
minutes are required to complete de-emanation.
8.12 Toward the end of the de-emanation, when the vacuum is no longer
effective, gradually increase the helium gas pressure. When the
system is at atmospheric pressure, shut off the helium gas, dis-
connect the tubing from the bubbler inlet and close the inlet and
outlet stopcocks of the cell and bubbler, and record time. This is
the beginning of radon-222 decay and ingrowth of radon-222
daughters.
8.13 Store the scintillation cell for at least 4 hours to ensure
equilibrium between radon and radon daughters. Count the alpha
scintillations from the cell in a radon counter with a light-tight
enclosure that protects the photomultiplier tube. Record the
counting time to correct for the decay of radon-222.
Note: After each analysis, flush the cell three times by evacua-
tion and filling with helium, and store filled with helium
at atmospheric pressure. This procedure removes radon from
the cell and prevents the build-up of radon daughter
products. Before each analysis, the scintillation cell
should be evacuated, filled with helium and counted to
ascertain the cell background.
9. Calculations
9.1 Calculate the radium-226 concentration, D, in picocuries per liter
as follows:
D =
where:
1
1
2.22 EV
C = net count rate, cpm,
E = calibration constant for the de-emanation system and the
scintillation cell in counts per minute/disintegrations per
minute of radon-222, (see 9.2),
V = liters of sample used,
l = the elapsed time in days between the first and second
de-emanations (steps 8.6 and 8.12) and X is the decay constant
of radon-222 (0.181 d-1),
2 = the time interval in hours between the second de-emanation
and counting and X is the decay constant of radon-222
(0.00755 hr-1),
46
-------
*3 = the counting time in minutes and A is the decay constant of
radon-222 (1.26 x 10"4 rain-1 )r and
2.22 = conversion factor from dpm/pCi.
9.2 The calibration constant, E, is determined by the following equation:
A
(e"At2)
where:
C = net count rate, cpm,
A = activity of radium-226 in the bubbler (dpm),
tl = ingrowth time of radon-222 in hours,
^2 = decay time of radon-222 in hours occurring between
de-emanation and counting, and
* = decay constant of radon-222, (0.00755 hour'1).
10. Precision and Accuracy
A number of laboratories which participate in the EPA, EMSL-Las Vegas
intercomparison program for radium-226 in water used this method in their
analyses of water samples received in that program for the period 4/78
through 12/78. Five intercomparison studies for radium-226 in water were
conducted during that period. Two of the five studies were "Performance
Studies" in which the sample contained other radionuclides. In the other
three studies the samples contained only radium-226, radium-228 and their
decay products. The radium-226 concentrations in the test samples for
the five studies ranged from 3.7 to 9.2 pCi/1, all low level, which
should relate well to drinking water supplies. Data from those five
studies were used for this precision and accuracy evaluation of the
method.
10.1 The number of laboratories that participated in the five studies
(labs that were called and indicated that they used this method)
ranged from 12 to 17 laboratories per study. The results from one
laboratory in one study was rejected as an "outlier" as determined
by the T test (ASTM Standards, Part 31, page 15, 1978). All labora-
tories reported triplicate analyses for each study (one test sample
per study). The total number of analyses for the five studies was
207 of which 174 were acceptable results (within 3 sigma of the
known value, 1 sigma being 15% of the known value). This calculates
to be 84% acceptability of results as determined by this method.
10.2 A statistical evaluation of the data from the five studies was made
according to the methods of Youden(4) and Steiner(S). The
coefficient of variation for within-laboratory error ranged from
6.4% to 19% with an average of 10.2% for the five studies. The
coefficient of variation for systematic error between laboratories
ranged from 14% to 18% with an average of 16.2% for the five
studies. The coefficient of variation for the total error between
laboratories based on a single analysis ranged from 16% to 26% with
47
-------
an average of 19.4% for the five studies. A comparison of the grand
average values with the known values in a test for systematic error
in a method gave a value for one of the studies higher than the
critical value, indicating a bias (low) for the method. However,
values for the other four studies were well below the critical
values, indicating no bias for the method.
Bibliography
1. Blanchard, R. L. Uranium Decay Series Disequilibrium in Age Determina-
tion of Marine Calcium Carbonates. Doctoral Thesis, Washington
University, St. Louis, Mo, (June 1963).
2. Ferri, E., P. J. Magno, and L. R. Setter. Radionuclide Analysis of Large
Numbers of Food and Water Samples. U. S. Department of Health,
Education, and Welfare, Public Health Service Publication No. 999-RH-17
(1965).
3. Rushing, D. E. The Analysis of Effluents and Environmental Samples from
Uranium Mills and of Biological Samples for Uranium, Radium and Polonium.
SM/41-44, Symposium on Radiological Health and Safety, Vienna., Austria
(August 1963).
4. Youden, W. J. "Statistical Techniques for Collaborative Tests,,"
Statistical Manual of the AOAC Association of Official Analytical
Chemists, Washington, D.C. 1975.
5. Steiner, E. H. "Planning and Analysis of Results of Collaborative
Tests." Statistical Manual of the AOAC, Association of Official
Analytical Chemists, Washington, D.C. 1975.
48
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SECTION 8
RADIUM-228 IN DRINKING WATER
METHOD 904.0
1. Scope and Application
1.1 This method covers the measurement of radium-228 in drinking water
and, if desired, the determination of radium-226 on the same
sample. The Interim Primary Drinking Water regulations state that
if the alpha screening test reveals a gross alpha activity above 5
pCi/1, a radium-226 analysis must also be performed. If the level
of radium-226 is above 3 pCi/1, the sample must also be measured
for radium-228.
1.2 This technique is devised so that the beta activity from
actinium-228 which is produced by decay of radium-228, can be
determined and related to the radium-228 that is present in the
sample.
1.3 To quantify actinium-228 and thus determine radium-228, the
efficiency of the beta counter for measuring the very short
half-lived actinium-228 (avg. beta energy-0.404 keV) is to be
calibrated with a beta source of comparable average beta energy.
2. Summary of Method
2.1 The radium in the drinking water sample is collected by
coprecipitation with barium and lead sulfate, and purified by
reprecipitation from EDTA solution. Both radium-226 and radium-228
are collected in this manner. After a 36-hour ingrowth of
actinium-228 from radium-228, the actinium-228 is carried on
yttrium oxalate, purified and beta counted. If radium-226 is also
desired, the activity in the supernate can be reserved for method
903.1 by coprecipitation on barium sulfate, dissolving in EDTA and
storing for ingrowth in a sealed radon bubbler.
3. Sample Handling and Preservation - (see Sec. 3, Method 900.0)
4. Interferences
4.1 As evidenced from the results of the performance studies, the
presence of strontium-90 in the water sample gives a positive bias
to the radium-228 activity measured.
49
-------
4.2 As in the case of method 903.0, excess barium in the drinking water
sample might result in a falsely high chemical yield.
5. Apparatus - See Appendix D for details and specifications
5.1 Gas-flow proportional counting system. (Low-background beta < 3
cpm).
5.2 Electric hot plate
5.3 Centrifuge
5.4 Membrane filters, metricel 47mm
5.5 Drying lamp
5.6 Glassware
5.7 Stainless steel counting planchets
5.8 Analytical balance
6. Reagents
6.1 Distilled or deionized water.
6.2 Acetic acid, 17.4N; glacial CI^COOH (cone.), sp. gr. 1.05, 99.8%
6.3 Ammonium hydroxide, 15^: NlfyOH (cone.), sp. gr. 0.90, 56.6%.
6.4 Ammonium oxalate, 5%: Dissolve 5g (NH4)2C204.H20 in
water and dilute to 100 ml.
6.5 Ammonium sulfate, 200 mg/ml: Dissolve 20g (NH4)2S04 in water
and dilute to 100 ml.
6.6 Ammonium sulfide, 2%: Dilute 10 ml (NH^S, (20-24%), to 100
ml with water.
6.7 Barium carrier, 16 mg/ml, standardized: (see Sec. 6, Method 903.0).
6.8 Citric acid, W: Dissolve 19.2g CeHsOy.h^O in water and
dilute to 100 ml.
6.9 EDTA reagent, basic (0.25M): Dissolve 20g NaOH in 750 ml water,
heat and slowly add 93g dTsodium ethylenedinitriloacetate
dihydrate, (Na2C-]oHi408N2-2H2°) while stirring. After
the salt is in solution, filter through coarse filter paper and
dilute to 1 liter.
50
-------
6.10 Lead carrier, 15 mg/ml: Dissolve 2.397g Pb(N03)2 in water, add
0.5 ml 16^ HNOs and dilute to 100 ml with water.
6.11 Lead carrier, 1.5 rag/ml: Dilute 10 ml lead carrier, (15 mg/ml), to
100 ml with water.
6.12 Methyl orange indicator, 0.1%: Dissolve O.lg methyl orange
indicator in 100 ml water.
6.13 Nitric acid, 16H: HNOs (cone.), sp. gr. 1.42, 70.4%.
6.14 Nitric acid, 6N_: Mix 3 volumes 16IN HN03 (cone.) with 5 volumes
of water.
6.15 Nitric acid, 1H: Mix 1 volume 6f[ HNOs with 5 volumes of water.
6.16 Sodium hydroxide, 18N: Dissolve 72g NaOH in water and dilute to
100 ml.
6.17 Sodium hydroxide,
100 ml.
Dissolve 40g NaOH in water and dilute to
6.18 Strontium carrier, 10 mg/ml: Dissolve 24.16 g Sr(N03)2 in
water and dilute to 1 liter.
6.19 Sulfuric acid, 18N_: Cautiously mix 1 volume 36!N ^04 (cone.)
with 1 volume of water.
6.20 Yttrium carrier 18 mg/ml: Add 22.85g \2®3 to an Erlenmeyer
flask containing 20 ml water. Heat to boiling and continue
stirring with a magnetic stirring hot plate while adding 16N^ HN03
in small amounts. Usually about 30 ml 16N^ HN03 is necessary to
dissolve the Y203. Small additions of water may be required to
replace that lost by evaporation. After total dissolution add 70.
ml 16N^ HN03 and dilute to 1 liter with water.
6.21 Yttrium carrier, 9 mg/ml: Dilute 50 ml yttrium carrier, (18
mg/ml), to 100 ml with water.
6.22 Strontium-yttrium mixed carrier, 0.9 mg/ml Sr+2 -0.9 mg/ml Y+3;
a. Solution A: Dilute 10.0 ml yttrium carrier, (18 mg/ml), to
100 ml.
b. Solution B: Dissolve 0.4348g Sr(N03)2 in water and dilute
to 100 ml.
Combine Solutions A and B and label.
51
-------
7. Calibrations
7.1 Counter efficiency: It is not practical to calibrate the beta
counter with actinium-228, since its' half-life is only six hours.
Standard strontium-89 (t-|/2 = 51d) may be substituted.
Strontium-89 has an average beta energy of 0.589 KeV, while the
average beta energy for actinium-228 is 0.404 KeV. A standard
strontium-89 tracer solution can be used 'to determine beta
efficiencies over a range of precipitate weights on the stainless
steel planchet.
7.2 If radium-226 analyses are also required, see Sec. 7, Method 903.1
8, Procedure 0)
8.1 For each liter of drinking water, add 5 ml 1IM
and few drops methyl orange indicator. The solution should be red.
Note: At the time of sample collection add 2 ml 16N[ HMOs for
each liter of water.
8.2 Add 10 ml lead carrier (15 mg/ml), 2 ml strontium carrier (10
rug/ml) 2.0 ml barium carrier (16 mg/ml), and 1 ml yttrium carrier
(18 mg/ml); stir well. Heat to incipient boiling and maintain at
this temperature for 30 minutes.
8.3 Add 15|[ NlfyOH until a definite yellow color is obtained, then add
a few drops excess. Precipitate lead and barium sulfates by adding
18IN HgS04 until the red color reappears, then add 0.25 ml
excess. Add 5 ml (NH4)2S04 (200 mg/ml) for each liter of
sample. Stir frequently and keep at a temperature of about 90°C
for 30 minutes.
8.4 Cool slightly, then filter with suction through a 47-mm metricel
membrane filter (GA-6,0.45 u-pore size). Make a quantitative
transfer of precipitate to the filter by rinsing last particles out
of beaker with a strong jet of water..
8.5 Carefully place filter with precipitate in the bottom of a 250 ml
beaker. Add about 10 ml 16N[ HN03 and heat gently until the
filter completely dissolves. Transfer the precipitate into a
polypropylene centrifuge tube with additional 16]^ HMOs .
Centrifuge and discard supernate.
8.6 Wash the precipitate with 15 ml 16N/HN03, centrifuge, and discard
supernate.
8.7 Repeat step 8.6.
8.8 Add 25 ml basic EDTA reagent, heat in a hot water bath, and stir
well. Add a few drops 10N_ NaOH if the precipitate does mot readily
dissolve.
52
-------
8.9 Add 1 ml strontium-yttrium mixed carrier and stir thoroughly.
a few drops 1(M NaOH if any precipitate forms.
Add
8.10 Add 1 ml (NH4)2$Q4 (2QO mg/ml) and stir thoroughly. Add
17 A^ CHaCOOH until barium sulfate precipitates, then add 2 ml
excess. Digest in a hot water bath until precipitate settles.
Centrifuge and discard supernate.
8.11 Add 20 ml basic EDTA reagent, heat in a hot water bath, and stir
until precipitate dissolves. Repeat steps 8.9 and 8.10. (Note
time of last barium sulfate precipitation; this is the beginning of
the actinium-228 ingrowth time.)
8.12 Dissolve the precipitate in 20 ml basic EDTA reagent as before,
then add 1.0 ml yttrium carrier (9 mg/ml) and 1 ml lead .carrier
(1.5 mg/ml). If any precipitate forms, dissolve by adding a few
drops 10IN NaOH. Cap the polypropylene tube and age at least 36
hours.
8.13 Add 0.3 ml (NH^S and stir well. Add ION. NaOH dropwise with
vigorous stirring until lead sulfide precipitates, then add 10
drops excess. Stir intermittently for about 10 minutes. Centri-
fuge and decant supernate into a clean tube.
8.14 Add 1 ml lead carrier (1.5 mg/ml), 0.1 ml (NH4)2S, and a few
drops 10r*[ NaOH. Repeat precipitation of lead sulfide as before.
Centrifuge and filter supernate through Whatman #42 filter paper
into a clean tube. Wash filter with a few ml water. Discard
residue.
8.15 Add 5 ml 18jt NaOH, stir well and digest in a hot water bath until
yttrium hydroxide coagulates. Centrifuge and decant supernate into
a beaker. Save for barium yield determination, step 8.20 (Note
time of yttrium hydroxide precipitation; this is the end of the
actinium-228 ingrowth time and beginning of actinium-228 decay
time.)
8.16 Dissolve the precipitate in 2 ml 6j^ HN03. Heat and stir in a hot
water bath about 5 minutes. Add 5 ml water and reprecipitate
yttrium hydroxide with 3 ml ION NaOH. Heat and stir in a hot water
bath until precipitate coagulates. Centrifuge and discard
supernate.
8.17 Dissolve precipitate with 1 ml lj^ HN03 and heat in hot water bath
a few minutes. Dilute to 5 ml and add 2 ml 5%
(NH4)2C204.H20. Heat to coagulate, centrifuge and
discard supernate.
8.18 Add 10 ml water, 6 drops IN^ HNOs and 6 drops 5%
(NH4)2C204.H20. Heat and stir in a hot water bath a few
minutes. Centrifuge and discard supernate.
53
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8.19 To determine yttrium yield, transfer quantitatively to a tared
stainless steel planchet with a minimum amount of water. Dry under
an infra-red lamp to a constant weight and count in a
low-background beta counter.
8.20 To the supernate from step 8.15, add 4 ml 16J^ HMOs and 2 ml
(NH4)2S04 (200 mg/ml), stirring well after each addition,
Add 17.W CHsCOOH until barium sulfate precipitates, then add 2
ml excess. Digest on a hot plate until precipitate settles.
Centrifuge and discard supernate.
8.21 Add 20 ml basic EDTA reagent, heat in a hot water bath, and stir
until precipitate dissolves. Add a few drops 10f[ NaOH if
precipitate does not readily dissolve.
8.22 Add 1 ml (1^4)2804 (200 mg/ml) and stir thoroughly. Add
17.4N^ CHsCOOH until barium sulfate precipitates, then add 2 ml
excess. Digest in a hot water bath until precipitate settles.
Centrifuge and discard supernate.
8.23 Wash precipitate with 10 ml water. Centrifuge and discard
supernate.
8.24 Transfer precipitate to a tared stainless steel planchet with a
minumum amount of water. Dry under an infra-red lamp and weigh for
barium yield determination.
9. Calculation
9.1 Calculate the radium-228 concentration, D, in picocuries per liter
as follows:
C x t0
D
x
1
x
1
2.22 x EVR
(l-e~xt2> (l-e'At3)
where:
C =
E =
V =
R =
2.22 s
X =
average net count rate, cpm,
counter efficiency, for actinium-228, or comparable 'beta
energy nuclide
liters of sample used,
fractional chemical yield of yttrium carrier (step 8.19)
multiplied by fractional chemical yield of barium carrier
(step 8.24),
conversion factor from disintegrations/minute to picocuries,
the decay constant for actinium-228 (0.001884 min-1),
(l-e"U2
is a factor to correct the average count rate to
count rate at beginning of counting time.
54
-------
tl = the time interval (in minutes) between the first yttrium
hydroxide precipitation in step 8.15 and the start of the
counting time,
*2 = the time interval of counting in minutes, and
*3 = the ingrowth time of actinium-228 in minutes measured from the
last barium sulfate precipitation in step 8.11 to the first
yttrium hydroxide precipitation in step 8.15.
10. Precision and Accuracy
10.1 In a single laboratory evaluation, an EMSL-Las Vegas Performance
Sample was analyzed in replicate for radium-228. The known value
of the water sample was 12.7 ± 1.9 pCi per liter. The grand
average reported by 33 laboratories was 17.1 ± 8.8 pCi per liter
indicating a positive bias reflecting the presence of other beta
emitters in the sample.
The result of the nine replicate analyses for radium-228 expressed
in pCi/1 were:
16.5
16.5
15.5
16.1
16.4
16.7
16.6
16.6
16.8
The average and standard deviation of the method was 16.4 ± 0.4
pCi/1.
The accuracy of the method based on the known value was +29%.
The accuracy of the method based on the reported grand average was
-4%.
The precision of the method was ±2.5%.
10.2 A number of laboratories which participate in the EPA, EMSL-Las
Vegas intercomparison program for radium-228 in water used this
method in their analyses of water samples received in that program
for the period 9/78 to 6/79. During that period five studies for
radium-228 in water were conducted. Three of the studies were
crosscheck samples which contained only radium-228 and radium-226
in water. The other two studies were performance (blind) samples
which contained other radionuclides, including strontium-90. Data
from the five studies were used for this precision and accuracy
statement of the method. However, data from the two types of
studies (crosscheck and performance) are treated separately because
there appears to be a bias in the performance sample studies.
The number of laboratories used for this data ranged from 8 to 15
laboratories per study. All laboratories reported triplicate
analyses for each study (one test sample per study). The total
number of analyses for the three cross check studies was 78, of
which 60 were acceptable results (within 3 sigma of the known
value, 1 sigma being 15% of the known value). This calculates to
55
-------
10.3
be 77% acceptability of results as determined by this method. The
total number of analyses for the two performance studies was 72, of
which 36 were acceptable for a 50% acceptability of results.
A statistical evaluation of the three cross check studies and the
two performance studies was done according to the methods of
Youden(2) and Steinen3). The coefficient of variation for
within-laboratory error was 15%, 19%, and 18% for the three cross
check studies; and was 21% for the two performance studies. The
coefficient of variation for systematic error between laboratories
was 23%, 23%, and 21% for the three cross check studies; and was
23% and 25% for the two performance studies. The coefficient of
variation for the total error between laboratories based on a
single analysis was 28%, 29%, and 28% for the three crosscheck
studies; and was 31% and 27% for the two performance studies.
A comparison of the grand average values with the known values in a
test for systematic error in a method gave a value for one of the
cross check studies higher than the critical value, indicating a
bias (low) for the method. However, values for the other two
crosscheck studies were well below the critical values, indicating
no bias for the method. On the other hand, when the same test was
applied to the data from the two performance studies, a high bias
was indicated for both studies (see Sec. 10.3 below).
Test for Method Bias
Study
Crosscheck
9/78
12/78
3/79
Performance
10/78
4/79
R(pCi/l)
20.8
8.9
13.6
5.4
6.2
x (pCi/1)
17.0
8.6
12.6
6.8
10.7
Calculated
t
2.56
0.43
1.05
3.01
5.00
Critical
t
2.32
2.23
2.32
2.15
2.28
This is a standard t-test with (n-1) degrees of freedom
t = (x-R) Vn~
S..
56
-------
where:
x = mean value of reported averages
R = known value
n = number of reported averages
Sx = standard deviation for the set of n reported averages.
Although the addition of man-made radionuclides to the performance
samples may be creating samples that are somewhat unreal it is desirable
that an approved EPA reference method for radium-228 in drinking water would
not be biased by those radionuclides.
The radium-228 concentrations in the test samples for the three
crosschecks and two performance studies are given in the above table (the R
values). These are all relatively low level and should relate well to
drinking water supplies.
References
3.
Johnson, J.O. Determirtaton of Radium-228 in Natural Waters.
Radiochemical Analysis of Water, Geological Survey Water - Supply Paper
1696-6., U.S. Govt. Printing Office, Washington, D.C. (1971).
Youden, W. J. "Statistical Techniques for Collaborative Test,"
Statistical Manual of the AOAC, Association of Official Analytical
Chemists, Washington, D.C. (1975).
Steiner, E.H. "Planning and Analysis of Results of Collaborative Tests,"
Statistical Manual of the AOAC, Association of Official Analytical
Chemists, Washington, D.C. (1975).
57
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SECTION 9
RADIOACTIVE STRONTIUM IN DRINKING HATER
Method 905.0
1. Scope and Application
1.1 This method covers the measurement of total strontium and soluble
strontium-89 and strontium-90 in drinking water. Some naturally
insoluble (and probably suspended) forms of strontium-89 and
strontium-90 would also be; measured by this method when samples of
such drinking water supplies are acid-preserved before analysis.
1.2 The Drinking Water Regulations under the Safe Drinking Water Act
set maximum contaminant concentrations for radionuclides in drink
ing water based on a 2 liter per day drinking water intake using
the 168 hour data listed in Handbook 69, National Bureau of Stand-
ards. The maximum contaminant concentration for strontium-89 and
strontium-90 are 80 pCi/1 and 8 pCi/1, respectively, the critical
organ being bone marrow. If other radionuclides are also present
in the drinking water, the sum of their annual dose equivalent must
not exceed 4 mrem per year. The Regulations also give a required
sensitivity of measurement which is defined in terms of a detection
limit. The required detection limits given for strontium-89 and
strontium-90 are 10 pCi/1 and 2 pCi/1, respectively. Appendix C
has equations for calculating the counting time necessary to meet
the required detection limit.
2. Summary of Method
2.1 Stable strontium carrier is added to the drinking water sample and
strontium-89 and strontium-90 are precipitated from the solution as
insoluble carbonates. Interferences from calcium and some radionu-
clides are removed by one or more precipitations of the strontium
carrier as strontium nitrate. Barium and radium are removed as the
chromate. The yttrium-90 daughter of strontium-90 is removed by a
hydroxide precipitation step and the separated combined
strontium-89 and strontium-90 are counted for beta particle activ-
ity. The counting result; immediately ascertained, represents the
total strontium activity (strontium-90 + strontium-89) plus an
insignificant fraction of the yttrium-90 that has grown into the
separated strontium-90. The yttrium-90 daughter grows in again and
is then separated with stable yttrium carrier as hydroxide and
finally precipitated as oxalate and beta counted. The strontium-90
concentration is determined by the yttrium-90 activity and the
strontium-89 concentration is then determined by difference.
58
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2.2 Counting efficiency data must be obtained with standard
strontium-89, strontium-90, :and yttrium-90 activities. These data
are used to make corrections since strontium-89, strontium-90, and
yttrium-90 emit beta particles with different energies.
3. Sample Handling and Preservation
3.1 It is recommended that samples be preserved with acid at the time
of collection. For preservation, sufficient acid should be added
to make the sample pH < 2.
3.2 The Drinking Water Regulations allow for the option of quarterly
compositing for an annual analysis or averaging the analyses of
four quarterly samples. It is especially recommended to preserve
composited samples.
3.3 It is recommended that no less than one liter size samples be
collected for analysis.
4. Interferences
4.1 Radioactive barium and radium will be carried down with radioactive
strontium as carbonate. This method includes steps to separate
strontium from barium and radium.
4.2 Samples that naturally contain significant amounts of stable
strontium will cause errors in the recovery of the added strontium
carrier. Blank samples to which no strontium carrier is added
should be run to determine natural strontium content. Hard waters
contain calcium which precipitates with the strontium in the
initial carbonate precipitation. If not separated, the calcium
will cause errors in the recovery of the strontium carrier.
Repeated precipitations with 16N^ HNOa (cone.) will eliminate this
interference.
5. Apparatus - See Appendix D for details and specifications.
5.1 Low background beta counting system (< 3 cpm background on the beta
voltage plateau is recommended).
5.2 Centrifuge and 50 ml centrifuge tubes
5.3 Drying oven
5.4 Hot water bath
5.5 Electric hot plate
5.6 Analytical balance
5.7 pH meter
59
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5.8 Desiccator, aluminum and/or glass
5.9 Stainless steel planchets9 2-inch diameter by 1/4-inch deep
5.10 Sintered-glass (fine) crucibles
5.11 Plastic ring and disc mounts
5.12 Mylar film
5.13 Teflon filter holder
5.14 Drying lamps
5.15 Glassware
6. Reagents
6.1 Distilled or deionized water is to be used, and all chemicals
should be of "reagent-grade" or equivalent whenever they are
commercially available.
6.2 Strontium carrier (10 mg/ml): Dissolve 24.16g Sr(N03)2 in water
and dilute to 1 liter in a volumetric flask with water. Mix
thoroughly.
Standardization: (In triplicate).
Carefully pipet 10.0-ml portions of the strontium carrier
solution into separate 50-ml centrifuge tubes. Add 1 ml 6N_
NaOH and heat in a water bath. Slowly, and with stirring, add
15 ml of 2N N32C03 solution (see sodium carbonate solution
below) ancTcontinue digesting for 15 to 20 minutes. Allow to
cool and filter the SrCOs precipitate through a tared
sintered-glass (fine) crucible. Wash the precipitate and the
crucible walls'with three 5-ml portions of distilled water
adjusted to pH 8 with 6J^ NltyOH, and with three 5-ml portions
of acetone. Dry the crucible for 30 minutes in a 105°C
oven. Cool the crucibles in a desiccator and weigh.
mg of SrCOg x 0.5935
Strontium, mg/ml =
10 ml
6.3 Yttrium carrier (10 mg/ml): Dissolve 43g Y(N03)3.6H20 in
water plus 5 ml 16]^ HMOs (cone.) and dilute to 1 liter in a
volumetric flask with water. Mix thoroughly.
60
-------
Standardization: (In triplicate).
Carefully pipet 10.0-ml portions of the yttrium carrier
solution into separate 50-ml centrifuge tubes. Add 30 ml
saturated (Nlty)20304.HgO to each centrifuge tube and
stir. Digest in a hot water bath (near boiling) for 30
minutes. Cool in an ice bath. Filter the precipitate onto a
Whatman #42 filter paper, then ignite in a tared crucible at
800°C for 1 hour to convert the oxalate to the oxide. Cool
and weigh the crucible and calculate the yttrium concentration
from the following equations.
Y/Y203
yttrium, mg/ml =
= 2 x 88.92/225.84 = 0.7875
mg of Y2°3 x 0.7875
10 ml
6.4 Acetic acid, 5.8J^: Mix 1 volume 17.4^ CHsCOOH (glacial) with 2
volumes of water.
6.5 Acetone,
: anhydrous.
6.6 Ammonium acetate buffer: Dissolve 154g NH4C2Hs02 in 800 ml
of water, add 57 ml 17. 4N^ COCOON (glacial), adjust the mixture
to pH 5.5 using COCOON or WtyOH. Dilute to 1 liter.
6.7 Ammonium hydroxide, 15j^: NftyOH (cone.), sp. gr. 0.90, 56.6%.
6.8 Ammonium hydroxide, 6IN: Mix 2 volumes 15£ NfyOH (cone.) with 3
volumes of water.
6.9 Ammonium hydroxide, O.INk Mix 1 volume 15j^ NfyOH (cone.) with
150 volumes of water.
6.10 Ammonium oxalate, saturated: Into 100 ml boiling water,
dissolve lOg (Nfy) 2C2°4- I-^O. Cool.
6.11 Barium carrier, (10 mg/ml): Dissolve 19.Og Ba(N03)2 in water
and dilute to 1 liter with water.
6.12 Hydrochloric acid, 6N; Mix 1 volume 12j\[ HC1 (cone.) with 1 volume
of water.
6.13 Methyl red indicator, 0.1%: Dissolve O.lg of methyl red in 100 ml
ethanol.
6.14 Nitric acid, 16N: HN03 (cone.) sp. gr. 1.42, 70.4%.
6.15 Nitric acid, 6N,: Mix 3 volumes 16N HN03 (cone.) with 5 volumes of
water.
61
-------
6.16 Nitric acid, IN; Mix 1 volume 6N_
with 5 volumes of water.
6.17 Phenolphthalein indicator, 1%: Dissolve Ig phenolphthalein in
50 ml ethanol and add 50 ml water.
6.18 Sodium carbonate, 2N; Dissolve 124g Na2C03.H20 (or io6g
in water and dilute to 1 liter with water.
6.19 Sodium chromate, 0.5M: Dissolve 117g N 32004. 4H20 in water
and dilute to 1 liter with water.
6.20 Sodium hydroxide, 6j^: Dissolve 240g NaOH in water and dilute to 1
liter with water.
6.21 Wetting agent solution: e.g. Photo-Flo, Eastman Kodak Co.
7. Calibrations
7.1 Counting Efficiencies - Separate counting efficiencies should be
determined for strontium-89 and strontium-90 using known amounts of
the respective radioactive standards and 20.0 mg of strontium
carrier, precipitated as carbonate and counted. A strontium-90
precipitate is prepared after separation of the yttrium-90 daughter
by the following procedure. Add a known amount of strontium-90
standard, in the order of 1000 disintegrations per minute (dpm),
and 20 mg of strontium carrier to a 50-ml centrifuge tube, add 20
ml of water and proceed as in steps 8.9 through 8.11. Then for the
yttrium-90 counting efficiency, continue with steps 8.12 through
8.16.
7.2 Sources of supply: For strontium-go-yttrium-go, the National
Bureau of Standards, Washington, DC offers a standard solution (SRM
4234) as listed in their latest catalog #260.
For strontium-89, Amersham Radiochemicals, Arlington Heights,
Illinois, offers a standardized aqueous solution essentially free
from strontium-90. This item is listed as SMZ.64 in their latest
catalog.
Standard sources of strontium-89 and strontium-90 are also
available from the Quality Assurance Division, U.S. Environmental
Protection, EMSL-Las Vegas.
8. Procedure
8.1 Transfer 1-liter water sample aliquots to 2-liter beakers. Add 2.0
ml each of strontium and barium carrier solutions to each sample
and blank beakers. Heat the samples to boiling and add 6'N NaOH
while stirring, to the phenolphthalein end point (red color), and
add 50 ml 2N^ Na2C03 solution. Continue heating to near boiling
for 1 hour with occasional stirring. Then set the beakers aside
for at least 2 hours, allowing the carbonate precipitate to settle.
62
-------
8.2 Decant most of the clear supernate and discard it. With the
remainder of the supernate",and necessary water washes (adjusted to
pH 8 with 6N^ NH40H), quantitatively transfer the precipitate to a
50-ml centrifuge tube. Centrifuge and discard the supernate. This
precipitate will contain the strontium and barium carriers.
8.3 Dissolve the precipitate by the dropwise addition of 4 ml 16N^
HN03.
8.4 Add 20 ml 16N^ HMOs to the centrifuge tube, cool in an ice bath
and stir. Centrifuge and discard the supernate which will contain
a significant fraction of the calcium present in the sample.
8.5 Add 20 ml 16_N HN03 to the centrifuge tube, cool in an ice bath
and stir. Centrifuge and discard supernate.
Note; If drinking water samples contain much calcium
(hardness), it will be necessary to repeat step 8.5.
8.6 Dissolve the strontium and barium nitrate precipitate in 25 ml
water, add 2 drops methyl red indicator, neutralize to yellow color
with 6N[ NH40H, then adjust the pH back to red color by adding
5.8N_ CHsCOOH dropwise.
8.7 Add 5 ml ammonium acetate buffer solution, and heat in a hot water
bath. Add, with stirring, 2 ml 0.5N[ Na2Cr04 and digest in the
hot water bath for 15 minutes. Cool the reaction mixture and
centrifuge. Transfer the supernate to a clean 50-ml centrifuge
tube, and discard the barium chromate residue.
Note: This residue can be saved if radioactive barium, radium,
or lead analysis is desired.
8.8 To the buffered chromate supernate add 2 ml 15N^ NhtyOH and heat in
a hot water bath. Add 5 ml 2]^ Na2C03 solution and digest for
15 minutes. Cool, centrifuge, and discard the supernate.
Note: In the next step, the strontium-89 and strontium-90 are
separated from yttrium-90 with a yttrium carrier scavenge
to start a specific ingrowth period and to get a separate
radiostrontium count in the following steps.
8.9 Add a few drops 16N[ HMOs to the carbonate precipitate, then add
25 ml water and 1 ml yttrium carrier. Add 1 drop of wetting agent
solution (such as "Photo-Flo," an Eastman Kodak Company film
processing product) and 5 ml 15N^ NlfyOH. Heat in a hot water bath
for 15 minutes with occasional stirring. Centrifuge and transfer
the supernate to a clean 50-ml centrifuge tube. Wash the yttrium
hydroxide precipitate with 5 ml water, centrifuge and add this wash
to the supernate. Note the time of'this yttrium hydroxide
precipitation which marks the beginning of the yttrium-90 ingrowth
period. From this point on it is important to proceed without
63
-------
delay to the final separation and count of the strontium-89 and
strontium-90 activity to minimize ingrowth of yttrium-90.
Note
Concentrated IWtyOH sometimes contains COg in solution
which will cause precipitation of some of the strontium
carrier in this step. If low carrier recoveries are
obtained in step 8.11, then for subsequent strontium
analyses, anhydrous NH3 gas may be substituted for
concentrated NH40H in step 8.9 by bubbling NHs gas in
the sample solution until the phenolphthalein end point
is reached, and then 5 minutes more. The same precaution
might be taken in step 8.14 to prevent carrydown of the
strontium-90 as the carbonate precipitate in that step.
8.10 Add 5 ml 2IN Na2C03 to the supernate from step 8.9, heat in a
hot water bath for about 10 minutes, centrifuge and discard the
supernate.
8.11 Slurry the strontium carbonate precipitate with a few ml water and
transfer quantitatively to a tared glass fiber filter. Wash the
precipitate with three 10-ml portions of water adjusted to pH 8
with NH40H, then with three 10-ml portions of acetone. During
filtration and washes of the strontium carbonate, minimize the time
of air flow through the filter to avoid collection of radon
daughters. Dry the filter at 105°C for 10 minutes, then weigh,
mount and count (within 2 hours). This count gives the total of
strontium-89 and strontium-90 activities, plus the ingrown
yttrium-90. Note the time of this count as it must be corrected
for yttrium-90 ingrowth (time between steps 8.9 and 8.11).
Note A: An alternative to step 8.11 involves the collection and
counting of the strontium carbonate precipitate on a
tared stainless steel planchet. 'For this, the approach
is as follows:
1. Slurry the strontium carbonate precipitate with a
few ml water and transfer quantitatively to a tared
stainless steel planchet. Dry under infrared lamp.
2. Cool, weigh, and beta count (within 2 hours).
Note B: The calculation of the total strontium activity D, in the
sample at this point in time can be made as fo'llows:
D =
where:
2.22 x EVR
C = net count rate, cpm,
E = counter efficiency, for strontium-90
V = liters of sample used,
64
-------
R = fractional chemical yield, and
2.22 = conversion factor from dpm/pCi.
$trontium-90 (By Yttrium-90)
8.12 After counting the strontium carbonate for strontium-89 and
strontium-90 activity, store the filter or the planchet for a
measured period of ingrowth, then proceed with the following steps
for yttrium-90 separation. A 2-week or longer ingrowth period is
recommended for samples with very low strontium-90 activity. Step
8.9 was the beginning of this ingrowth period.
8.13 Undo the mylar covering from the nylon ring and disc, and transfer
the filter to a small funnel which has been placed to drain into a
50 ml centrifuge tube. Dissolve the strontium precipitate by
carefully wetting the filter with 5 ml of 6j^ HMOs. Wet the
filter with 2.0 ml yttrium carrier. Rinse the strontium and
yttrium into the centrifuge tube by washing the filter with four
5-ml portions of IN HMOs- Remove the funnel from the centrifuge
tube, discard the Filter, and add 1 drop of wetting agent solution
to the centrifuge tube. Swirl the tube to mix the contents
thoroughly.
Note; In the case of the stainless steel planchet:
1. After the period for yttrium-90 ingrowth, slurry the
precipitate on the planchet with 2 ml water and transfer
to a centrifuge tube with the aid of a rubber policeman.
To make the transfer quantitative, wash the residue from
the planchet with a small -amount of IN HN03. Dissolve
the precipitate in the tube with sufficient IN^
and dilute with water to 10 ml.
2. Add 2.0 ml yttrium carrier and stir.
3. Boil to expel dissolved carbon dioxide; cool to room
temperature.
8.14 Precipitate the yttrium as hydroxide by adding 10 ml 15]^ NlfyOH to
the centrifuge tube, stirring and heating for 10 minutes in a hot
water bath. Cool, centrifuge and decant supernate into a 100-ml
beaker. Note time of last precipitation; this is the end of
yttrium-90 ingrowth and the beginning of yttrium-90 decay.
8.15 Dissolve precipitate in 1 ml 1J^ HN03 and dilute with water to 10
ml.
8.16 Reprecipitate yttrium by dropwise addition of 15N^ NH40H.
8.17 Centrifuge and combine supernate with solution in the 100-ml beaker
(step 8.14).
65
-------
8.18 Repeat steps 8.15, and 8.]6. Save the combined supernates in the
beaker for strontium gravimetric yield determination, step 8.22.
Note: Steps 8.22 to 8.25 are a repeat of the strontium carbonate
precipitation to determine chemical yield after the yttrium
has been removed.
8.19 Dissolve the precipitate in 15 ml water containing 2 ml 6N^ HC1.
Precipitate the yttrium as oxalate by adding 20 ml saturated
(NH4)2C204 and heating for 30 minutes in a hot water bath
(near boiling). Cool in an ice bath and then filter the yttrium
oxalate onto a Whatman #42 filter (4.25 cm diameter). Wash the
precipitate with three 5-ml portions of water, then with three 5-ml
portions of acetone. Air dry the filter for about 1 hour.
Note: A pH of 1.7-1.9 in the solution from which yttrium oxalate
is being precipitated is necessary to get a uniform 9H20
hydrate precipitate. This is necessary if the analyst
prefers and is going to weigh the yttrium oxalate for
chemical yield. Also, the analyst may then prefer to use a
tared glass fiber filter instead of a Whatman #42 paper
filter. The filter plus oxalate precipitate is weighed to
determine chemical yield (recovery). See note following 9.1
for calculations. If this procedure is followed, step 8.21
can be eliminated.
8.20 Mount filter on a plastic ring and disc, and count for yttrium-90
activity. Record the time,of the counting for decay correction
(time between 8.14 and count time).
8.21 Undo the mylar covering, and transfer the filter to a tared
crucible. Ignite at 800°G for 1 hour in a muffle furnace to
convert the oxalate to the oxide. Cool and weigh the crucible.
Determine the yttrium recovery (see Section 9.1).
8.22 Warm the combined supernates from step 8.14, add 5 ml 2N_
N32C03, and digest for 10 minutes. Cool, centrifuge, and
discard supernate.
8.23 Wash the SrCOs with 15 ml water and discard wash solution.
8.24 Slurry with a few ml water and transfer quantitatively to a tared
stainless-steel planchet. Dry under infrared lamps.
8.25 Cool and weigh the planchet. Determine the strontium recovery (see
Section 9.1).
9. Calculations
9.1 Chemical yields for strontium and yttrium
66
-------
mg SrC03 recovered
a = Yield factor for Sr = mg Sr carrier added (as carbonate)
20.0 mg of strontium is equivalent to 33.7 mg
mg Y0 recovered
b = Yield factor for Y = mg Y carrier added (as oxide)
20.0 mg of yttrium is equivalent to 25.4 mg of Y^.
Note: If chemical yield is to be determined from the yttrium
oxalate precipitate the following calculations are used.
mg Y2(C204)3.9H20
b = yield factor for Y = mg Y carrier added (as oxalate)
20.0 mg of yttrium is equivalent to 67.9 mg of yttrium oxalate,
9.2 Calculations for Activities at Equilibrium Conditions:
Indicated cpm values are net cpm (reagent blank, including
background, subtracted).
90
Y cpm
90Y dpm = abefi
90Sr dpm
90Sr cpm = 90Y dpm x c
Total 89,90$r Cpm = total cpm (SrCOs) - ingrown 90Y cpm
Ingrown 90Y cpm = 90Sr cpm x e x g
total Sr cpm - 90Sr cpm - 90Sr dpm x e x g
89Sr cpm = a
89Sr dpm = 89Sr cpm
d
PCi/liter =
90
89Sr pCi/liter = ^|F
where:
67
-------
c = strontium-90 counting efficiency,
d = strontium-89 counting efficiency,
e = yttrium-90 counting efficiency,
f s yttrium-90 decay factor,
g s yttrium-90 ingrowth factor, for unwanted yttrium-90 in total
strontium-89, strontium-90 count,
h = strontium-89 decay factor,
V == volume of sample analyzed, in liters,
i = yttrium-90 ingrowth factor for strontium-90 by yttrium-90
determination, and
2.22 = conversion factor from dpm/pCi.
Error associated with the results of the analysis should also be
reported. See Section 10 for error and statistical calculations, for
yttrium-90 decay and ingrowth'factors, and for strontium-89 decay
factors.
10. Calculation Factors
10.1 Error and Statistical Calculations - Because of the random nature
of radioactivity disintegrations, there is an error associated with
any measured count of these disintegrations. The variability of
any measurement is indicated by the standard deviation. The
standard deviation in the counting rate, (R). is determined by the
following equation:
0(R) -
0 +
B
'1
1/2
where:
R =
B =
t2 =
Let a(R-j) = DI
gross count rate
counting time for the gross count
background count rate
counting time for the background count
= standard deviation for the count of total
strontium-89 and strontium-90 (from SrCO^
precipitate, which includes the unwanted ingrown
yttrium-90).
Let <*(Rg) = D2 = standard deviation for the yttrium-90 count for
strontium-90 determination
The counting errors, E, for a given sample for the strontium-89 and
strontium-90 determinations expressed in pCi/liter are shown as
follows:
For 90sr, E =
For 89sr, E =
1.96 -D,
1000
2.22xabefiV
1.96 x 1000
2.22 x adV
(D/ +
c + e x g
befi j
1/2
68
-------
where:
1.96 = 95% confidence factor
1000 = ml/liter
2.22 = conversion factor from disintegrations/minute to picocuries
a = strontium recovery factor
b = yttrium recovery factor
c = strontium-90 counting efficiency
d = strontium-89 counting efficiency
e = yttrium-90 counting efficiency
f = yttrium-90 decay factor
g = ingrowth factor for unwanted yttrium-90 in total
radiostrontium count
i = ingrowth factor for yttrium-90 for strontium-90 determination
These were derived by applying propagation of error theory to the
expressions in Section 9.3.
The standard deviations of a number of experimental analyses or
observations is determined by:
S =
n
I
1=1
- x)2/n -
1/2
where:
x-j = activity (pCi/liter) of a given sample
X = mean activity (pCi/liter) of a series of analyses
n = the number of replicate analyses
69
-------
10.2 Yttrium-90 Decay and Ingrowth Factors (0-71 Hours)
t(hr) e-xt l-e~xt t(hr) e-^ 1-e-^t t(hr)
45.0
45.5
46.0
46.5
47.0
47.5
48.0
48.5
49.0
49.5
50.0
50.5
51.0
' 51.5
52.0
52.5
53.0
53.5
54.0
54.5
55.0
55.5
56.0
56.5
57.0
57.5
58.0
58.5
59.0
59.5
60.0
60.5
61.0
61.5
62.0
62.5
63.0
64.0
65.0
66.0
67.0
68.0
69.0
70.0
71.0
e"
""At
'"j — Q™"
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5'
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0
16.5
17.0
17.5
18.0
18.5
19.0
19.5
20.0
20.5
21.0
21.5
22.0
1.0000
.9940
.9893
.9839
.9786
.9734
.9681
.9629
.9577
.9526
.9474
.9423
.9373
.9322
.9272
.9222
.9172
.9123
.9074
.9025
.8976
.8928
.8880
.8832
.8785
.8737
.8690
.8644
.8597
.8551
.8505
.8459
.8413
.8468
.8323
.8278
.8234
.8189
.8145
.8101
.8058
.8014
.7971
.7928
.7885
.0000
.0054
.0107
.0161
.0214
.0266
.0319
.0371
.0423
.0474
.0526
.0577
.0627
.0678
.0728
.0778
.0828
.0877
.0926
.0975
.1024
.1072
.1120
.1168
.1215
.1263
.1310
.1356
.1403
.1449
.1495
.1541
.1587
.1632
.1677
.1722
.1766
.1811
.1855
.1899
.1942
.1986
.2029
.2072
.2115
22.5
23.0
23.5
24.0
24.5
25.0
25.5
26.0
26.5
27.0
27.5
28.0
28.5
29.0
29.5
30.0
30.5
31.0
31.5
32.0
32.5
33.0
33.5
34.0
34.5
35.0
35.5
36.0
36.5
37.0
37.5
38.0
38.5
39.0
39.5
40.0
40.5
41.0
41.5
42.0
42.5
43.0
43.5
44.0
44.5
.7843
.7801
.7759
.7717
.7676
.7634
.7593
.7552
.7512
.7471
.7431
.7391
.7351
.7311
.7272
.7233
.7194
.7155
.7117
.7078
.7040
.7002
.6965
.6927
.6890
.6853
.6816
.6779
.6743
.6706
.6670
.6634
.6599
.6563
.5428
.6493
.6458
.6423
.6388
.6354
.6320
.6286
.6252
.6219
.6185
.2157
.2199
.2241
.2283
.2324
.2366
.2407
.2448
.2488
.2529
.2569
.2609
.2549
.2689
.2728
.2767
.2806
.2845
.2883
.2922
.2960
.2998
.3035
.3073
.3110
.3147
.3184
.3221
.3257
.3294
.3330
.3366
.3401
.3437
.3472
.3507
.3542
.3577
.3612
.3646
.3680
.3714
.3748
.3781
.3815
.6151
.6118
. 6085
.6053
.6020
.5988
. 5955
.5923
.5891
.5860
.5828
.5797
.5766
.5735
.5704
.5673
.5642
.5612
.5582
.5552
.5522
.5492
.5462
.5433
.5404
.5375
.5346
.5317
.5288
.5260
.5232
.5203
.5175
.5148
.5092
.5092
.5065
.5010
.,4957
.4903
.4851
.4799
.4747
,.4696
.4646
.3849
.3882
.3915
.3947
.3980
.4012
.4045
.4077
.4109
.4140
.4172
.4203
.4234
.4265
.4296
.4327
.4358
.4388
.4418
.4448
.4478
.4508
.4538
.4567
.4596
.4625
.4654
.4683
.4712
.4740
.4768
.4797
.4825
.4852
.4880
.4908
.4935
.4990
.5043
.5097
.5149
.5201
.5253
.5304
.5354
70
-------
10.3 Yttrium-90 Ingrowth Factors (0-27 days)
t(days) l-e-^t t(days) 1-e-xt
t(days)
l-e-At
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
2.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
4.50
4.75
5.00
5.25
5.50
5.75
6.00
6.25
6.50
6.75
7.00
7.25
7.50
7.75
8.00
8.25
8.50
8.75
.0000
.0627
.1215
.1766
.2283
.2767
.3221
.3646
.4045
.4418
.4768
.5097
.5404
.5692
.5963
.6216
.6453
.6676
.6884
.7080
.7263
.7435
.7596
.7746
.7888
.8020
.8145
.8261
.8370
.8472
.8568
.8658
.8742
.8820
.8896
.8864
9.00
9.25
9.50
9.75
10.00
10.25
10.50
10.75
11.00
11.25
11.50
11.75
12.00
12.25
12.50
12.75
13.00
13.25
13.50
13.75
14.00
14.25
14.50
14.75
15.00
15.25
15.50
15.75
16.00
16.25
16.50
16.75
17.00
17.25
17.50
17.75
.9029
.9090
.9147
.9201
.9251
.9298
.9342
.9384
.9422
.9458
.9492
.9524
.9554
.9582
.9608
.9633
.9656
.9678
.9697
.9716
.9734
.9751
.9766
.9781
.9795
.9808
.9820
.9831
.9842
.9852
.9861
.9870
.9878
.9886
.9893
.9900
18.00
18.25
18.50
18.75
19.00
19.25
19.50
19.75
20.00
20.25
20.50
20.75
21.00
21.25
21.50
21.75
22.00
22.25
22.50
22.75
23.00
23.25
23.50
23.75
24.00
24.25
24.50
24.75
25.00
25.25
25.50
25.75
26.00
26.25
26.50
26.75
27.00
.9906
.9912
.9917
.9922
.9927
.9932
.9936
.9940
.9944
.9948
.9951
.9954
.9957
.9959
.9962
.9964
.9967
.9969
.9971
.9973
.9974
.9976
.9977
.9979
.9980
.9981
.9982
.9984
.9985
.9986
.9987
.9987
.9988
.9989
.9990
.9990
.9991
71
-------
10.4 Strontium-89 Decay Factors (0-59.5 days) (t 1/2 = 51 days)
t(days) e-Xt t(days) e-Xt t(days) e"'Xt
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0
16.5
17.0
17.5
18.0
18.5
19.0
19.5
1.0000
.9932
.9865
.9798
.9732
.9668
.9601
.9536
.9471
.9407
.9344
.9280
.9217
.9155
.9093
.9031
.8970
.8909
.8849
.8789
.8729
.8670
.8612
.8553
.8495
.8438
.8381
.8324
.8268
.8212
.8156
.8101
.8046
.7991
.7938
.7883
.7881
.7778
.7725
.7672
20.0
20.5
21.0
21.5
22.0
22.5
23.0
23.5
24.0
24.5
25.0
25.5
26.0
26.5
27.0
27.5
28.0
28.5
29.0
29.5
30.0
30.5
31.0
31.5
32.0
32.5
33.0
33.5
34.0
34.5
35.0
35.5
36.0
36.5
37.0
37.5
38.0
38.5
39.0
39.5
.7620
.7569
.7518
.7568
.7416
.7366
.7317
.7267
.7218
.7169
.7120
.7072
.7023
.6977
.6930
.6882
.6836
.6790
.6742
.6699
.6651
.6608
.6562
.6519
.6473
.6430
.6388
.6342
.6300
.6259
.6215
.6172
.6131
.6090
.6050
.6009
.5968
.5928
.5888
.5848
40.0
40.5
41.0
41.5
42.0
42.5
43.0
.5808
.5769
.5730
.5690
.5652
.5613
.5575
43.5
44.0
44.5
45.0
45.5
46.0
46.5
47.0
47.5
48.0
48.5
49.0
49.5
50.0
50.5
51.0
51.5
52.0
52.5
53.0
53.5
54.0
54.5
55.0
55.5
56.0
56.5
57.0
57.5
58.0
58.5
59.0
59.5
.5539
.5500
.5462
.5427
.5380
.5352
.5318
.5280
.5245
.5210
.5175
.5140
.5105
.5070
.5035
.5000
.4967
.4933
.4900
.4868
.4834
.4801
.4769
.4734
.4702
.4671
.4640
.4608
.4578
.4547
.4513
.4484
.4454
72
-------
11. Precision and Accuracy
11.1 In a single operator test of the method, two sets of five water
samples containing known amounts of strontium-89, strontium-90s
were analyzed for those radionuclides. The average recovery of
added strontium-90 was 95 and 94 percent for the two sets of
samples at a precision of 3 and 5 percent at the 95 percent
confidence level.
11.2 In a collaborative test of the method with 13 laboratories
participating, three samples containing known amounts of
strontium-89 and strontium-90 were analyzed (Samples A, B and C).
11.3 The data of two laboratories for all three samples for
'strontium-90 were rejected because their scores in the ranked
results of the laboratory averages were outside the acceptable
range for 13 laboratories and 3 samples.
11.4 The coefficients of variation for the three samples ranged from
11.3% for 1000 pCi/1 concentrations to 57% for 10 pCi/1
concentrations. i
11.5 The coefficients of variation for the combined within-laboratory
precision for strontium-90 in the three samples ranged from 13.6%
for 1000 pCi/1 concentrations to 23% for 10 pCi/1 concentrations.
11.6 The coefficients of variation for the precision of the method
between laboratories for strontium-89 in the three samples ranged
from 20% for 1000 pCi/1 concentrations to 43% for 10 pCi/1
concentrations.
11.7 The coefficients of variation for the precision of the method
between laboratories for strontium-90 in the samples ranged from
15% for 1000 pCi/1 concentrations to 44% for 10 pCi/1
concentrations.
11.8 The coefficients of variation for the total error between
laboratories based on a single analysis for strontium-89 in the
three samples ranged from 23% for 1000 pCi/1 concentrations to 71%
for 10 pCi/1 concentrations.
11.9 The coefficients of variation for the total error between
laboratories based on a single analysis for strontium-90 in the
three samples ranged from 17% for 1000 pCi/1 concentrations to 46%
for 10 pCi/1 concentrations.
11.10 In the statistical test to detect method bias, no significant bias
was shown in the analysis of the three samples for strontium-89.
In the analysis of the three samples for strontium-90, sample C
(1000 pCi/1 concentration) showed a low bias but not seriously.
73
-------
11.11 The strontium-89 analysis of samples A, B, and C deviated from the
known values by the factor 1.49, 1.01, and 1.03, respectively.
The strontium-90 analysis of samples A, B, and C deviated from the
known values by the factors 1.00, 0.899, and 0.820, respectively.
Bibliography
1. EPA Drinking Water Regulations, Federal Register, Vol. 41, No. 133,
Friday July 9, 1976, Part 141.
2. American Public Health Association. Standard Methods for the
Examination of Water and Wastewater, 13th Edition, Washington, D.C. 1971.
3. American Society for Testing and Materials. 1976 Annual Book of ASTM
Standards, Part 31, Philadelphia, PA.
4. Dixon, W.J., and F. J. Massey, Jr. Introduction to Statistical
Analysis, McGraw-Hill, 1969.
5. HASL-300, Health and Safety Laboratory, ERD, 376 Hudson Street, New
York, New York 10014.
6. Steiner, E.H., 1975. Planning and Analysis for Results of Collaborative
Tests, Statistical Manual of the AOAC, Association of Official
Analytical Chemists, Washington, D. C.
7. Youden, W. J. 1969. Precision Measurements and Calibration. H. H. Ku,
editor. National Bureau of Standards, Special Publication 300, Vol. 1.
8. Youden, W. J. 1975. Statistical Techniques for Collaborative Tests.
Statistical Manual of the AOAC. Association of Official Analytical
Chemists, Washington, D. C.
9. Douglas, 6. S., ed. Radioassay Procedures for Environmental Samples,
Environmental Health Series, USDHEW Rept. 999-RH-27, National Center for
Radiological Health, Rockville, Md. 10852 (Jan. 1967).
10. Hahn, R.B., and C. P. Straub. "Determination of Radioactive Strontium
and Barium in Water." J. Am. Water Works Assoc. 47 (4) 335-340 (April
1955)
11. Goldin, A. S., R. J. Velten and G. W. Frishkorn, "Determination of
Radioactive Strontium," Anal. Chem. 31, 1490 (1959).
74
-------
SECTION 10
TRITIUM IN DRINKING WATER
METHOD 906.0
1. Scope and Application
1.1 This method covers the measurement of tritium (as T20 or HTO) in
a sample of drinking water by liquid scintillation spectrometry.
This technique assures the identification of tritium in drinking
water at a concentration fifty-fold lower than promulgated in the
Safe Drinking Water Act, PL 93-523.
1.2 The maximum contaminant level for tritium in drinking water as
given in the National Interim Primary Drinking Water Regulations
(NIPDWR) is 20,000 pCi/1. The NIPDWR list a required detection
limit for tritium in drinking water of 1000 pCi/1 or 1 pCi/ml,
meaning that drinking water supplies, where required, should be
monitored for tritium at a sensitivity of 1 pCi/ml. In Appendix C,
the use of equation (3) will determine the necessary counting time
required to meet the sensitivity for drinking water monitoring.
t .
1.3 By counting standard tritium and background samples at the same
time as the prepared drinking water samples, the results and the
behavior of the liquid scintillation spectrometer can be routinely
monitored.
2. Summary of Method
2.1 A 100 ml aliquot of a drinking water sample is treated with a small
amount of sodium hydroxide and potassium permanganate, then is
distilled, and a specified fraction of the distillate is collected
for tritium analysis. The alkaline treatment prevents other radio-
nuclides such as radioiodine and radiocarbon from distilling over
with the tritium. Some drinking water supplies will contain trace
quantities of organic compounds (especially surface water sources
that contain fish and other life). The permanganate treatment
oxidizes trace organics in the sample aliquot which could distill
over and cause quenching interferences. A middle fraction of the
distillate is collected for tritium analysis because the early and
late fractions are more apt to contain interfering materials for
the liquid scintillation counting process.
2.2 The collected distillate fraction is thoroughly mixed and a portion
is mixed with liquid scintillator solution, and after dark
75
-------
adapting, is counted in the liquid scintillation counting system
for tritium beta particle activity.
2.3 The scintillator solution, mixed with the radioactive sample, is
excited by beta particles and emits light pulses by a molecular
de-excitation process. The number of pulses per unit time is
proportional to the quantity of activity present. Multiple solutes
are used in the scintillator to provide the best combination of
wavelength and pulse height for this application. The pulses are
detected by two photomultiplier tubes connected in coincidence and
converted to electric signals. The amplified pulses are recorded
and the count rate is measured. The efficiency of the system can
be determined by use of prepared tritiated water standards having
the same density and color as the sample.
3. Sample Handling and Preservation
3.1 The drinking water sample should be collected in its natural state,
and should not be acidified. Since tritium in drinking water is
very much apt to be in the form of T20 or HTO there is no need
for special handling or preservation.
4. Interferences
4.1 Tritium in background water is an interference. Slightly elevated
levels are present in surface waters so deep well sources for
background water should be used.
4.2 All fluors should be checked for excitation under lighting
conditions being used and if necessary they should be exposed only
to red light. Dioxane-base scintiHaters exposed to fluorescent
lighting should be dark-adapted for 24 hours. Toluene-or
xylene-base scintiHaters exposed to fluorescent lighting should be
dark-adapted for a minimum of 1 hour. ;
4.3 The use of plastic vials may cause build-up of static charge and
give erratic results.
5. Apparatus - See Appendix D for details and specifications.
5.1 Coincidence-type liquid scintillation spectrometer.
5.2 Liquid scintillation vials: Low-potassium glass is recommended.
Polyethylene vials may be used when dioxane liquid scintillator
solution is used.
5.3 Distillation apparatus: For aqueous distillation: 250-m'l and
1000-ml round bottom pyrex flasks, connecting side arm adapter
(such as Corning part #9060), condenser, graduated cylinder,
boiling chips, and heating mantle.
76
-------
6. Reagents
6.1 Reagents for distillation treatment: sodium hydroxide pellets and
potassium permanganate. (ACS - reagent grade)
*
6.2 Background water with tritium activity below the minimum detectable
activity (most deep well waters are low in tritium content).
6.3 Scintillator solutions:
6.3.1 Solution G liquid scintillator solution: Dissolve 18g
scintillation-grade PRO (2,5-diphenyloxazole) and 3.6g
scintillation-grade BIS-MSB p-bis(o-methy1styryl)benzene
in 2 liters of spectroquality p-xylene. Add 1 liter Triton
N-101 detergent (Rohm & Haas) to the p-xylene scintillator
solution. Dissolve 50g SXS (sodium xylene sulfonate) in 100
ml distilled water and add this solution to the p-xylene
scintillator-Triton solution. Mix thoroughly. Store the
solution in a dark (amber) bottle. The organic solvent
evaporates slowly through the wall of the polyethylene
vials. For this reason counting samples should be completed
within 3 days after preparation.
6.3.2 Detergent-type liquid scintillator solutions are available
as commercial preparations. They are also prepared with
aromatic hydrocarbon solvents and should therefore, when
used with plastic vials, be counted within 3 days for the
reason stated above. (See Representative Sources of
Laboratory Supplies, Appendix E)
6.3.3 Dioxane liquid scintillator solution: Dissolve 4g
scintillation-grade PRO (2,5-diphenyloxazole), O.OSg
scintillation-grade POPOP l,4-bis(5-phenyloxazolyl-2-yl)
benzene , and 120g naphthalene in 1 liter of spectroquality
1,4-dioxane. Store the solution in a dark (amber) bottle.
This solution can be used with glass or polyethylene vials.
7. Calibrations
7.1 Determination of Recovery and Counting Efficiency Factors - (See
calculations, Sec. 9.2 and 9.3)
7.1.1 Into a 1-liter volumetric flask, pipette a tritium standard
solution containing approximately 1000 disintegrations per
minute (dpm) per m.l and dilute to volume using low level
tritium background raw water (undistilled) and standard
tritium activity. Label this solution "Raw Water Tritium
Standard Solution." For tritium background determinations,
distill approximately 600 ml of water, obtained from the
same raw water source as above (without tritium activity
added). Using the distillate and standard tritium activity,
77
-------
7.1.2
7.1.3
prepare a tritium standard solution in a 500-ml volumetric
flask containing the same specific activity as the "Raw
Water Tritium Standard Solution." Label this solution
"Distilled Water Tritium Standard Solution."
Aqueous permanganate distillation:
To a 100-ml aliquot of the "Raw Water Tritium Standard
Solution" in a 250-ml distillation flask, add 0.5g sodium
hydroxide, O.lg potassium permanganate, and a boiling chip.
Proceed according to the procedure described in section
8.1. Discard the first 10 ml and collect 50 ml of the dis-
tillate for analysis. Mix well. Repeat the distillation
with two more 100-ml aliquots for triplicate analyses.
For liquid scintillation counting:
Prepare 3 aliquots of the "Raw Water Tritium Standard
Solution" distillate (from step 7.1.2), 3 aliquots of the
"Distilled Water Tritium Standard Solution;" and 3 aliquots
of the distilled raw water (for background). Mix 4 ml water
with 16 ml of the dioxane scintillator solution or 8 ml
water with 12 ml of a detergent-type scintillator solution
in a liquid scintillator vial (glass vials should be used
for detergent-type scintillator solutions). Shake well and
dark-adapt the vials overnight. Count each vial in a liquid
scintillation counter long enough to meet the required
detection limit (1 pCi/ml) or longer (see Appendix C for
calculating required counting time).
8. Procedure
8.1 Add 0.5g sodium hydroxide and O.lg potassium permanganate to a
100-ml aliquot of the sample in a 250-ml distillation flask. Add a
boiling chip to the flask. Connect a side arm adapter and a
condenser to the outlet of the flask, and insert a graduated
cylinder at the outlet of the condenser (Fig. 5). Heat the sample
to boiling to distill, and discard the first 10 ml of distillate as
a separate fraction. (It is important that the first;10-ml
fraction for samples and standards alike be discarded, since there
is a gradient in the tritium concentration of the distillate).
Collect the next 50-ml of distillate for tritium analysis and mix
thoroughly.
8.2 Mix 4 ml of the distillate with 16 ml of the dioxane liquid
scintillator or 8 ml of the distillate with 12-ml of a
detergent-type scintillator solution in a liquid scintillation vial.
8.3 Prepare background and standard tritium water solutions for
counting, using the same amount of water and the same scintillator
as used in the preparation of samples. Use low tritium background
distilled water for these preparations (distillate of most deep
well water sources is acceptable, but each source should be checked
for tritium activity before using).
78
-------
r—
ea
c
(O
•»J
•I—
s_
03
H3
Q-
O.
ro
C
O
CO
Q
OJ
S-
-3
79
-------
8.4 Dark-adapt all samples, backgrounds, and standards. Count the
samples, backgrounds, and standards at least long enough to meet
the required detection limit (1 pCi/ml) for the sample (see
Appendix C for calculating required time).
Note: In normal counting operation, tritium is counted with a
window setting where the figure of merit is at maximum.
Figure of Merit =
(Efficiency)'
(Background)
9. Calculations
9.1 Calculate the tritium concentration, A, in picocuries per liter as
follows:
A =
where:
( C - B ) x 1000
2.22 x E x V x F
C = sample count rate, cpm,
B - background count rate, cpm,
E = counting efficiency, as determined in Sec. 9.2,
V = volume of the sample aliquot in ml,
F = recovery factor, as determined in Sec. 9.3
2.22 ~ conversion factor for dpm/pCi.
9.2 Determine the counting efficiency, E, as follows:
c D - B
E _ ^
where:
D = distilled water standard count rate, cpm,
B = background count rate, cpm, and
6 = activity of distilled water standrd (dpm)
9.3 Calculate the recovery correction factor, F, as follows:
L - B
F =
E x M
where:
L = raw water standard distillate count rate, cpm,
B = background count rate, cpm,
E - counting efficiency, as determined in Sec. 9.2, and
M = activity of raw water .standard (before distillation), dpm.
80
-------
10. Precision and Accuracy
10.1 In an inter!aboratory collaborative test of the method three water
samples were analyzed for tritium by 25 laboratories. The three
water samples were prepared by spiking tap water with measured
amounts of tritiated water of known concentrations.
10.2 The data from three laboratories for the three water samples were
rejected from the statistical analysis because their scores in the
ranked results of the laboratory averages were outside the
acceptable range for 25 laboratories and 3 samples.
10.3 The coefficients of variation for the combined within-laboratory
precision for the three samples ranged from 2.1 to 5.2 percent.
10.4 The coefficients of variation for the precision of the method
between laboratories for the three samples ranged from 21.0 to 28.8
percent.
10.5 The coefficients of variation for the total error between
laboratories based on a single analysis for the three samples
ranged from 21.3 to 29.2 percent.
10.6 In the statistical test to detect method bias, the method showed no
bias for tritium concentrations at the 7 pCi/ml level to a small
bias on the low side for concentrations at the 300 pCi/ml level
(average analytical value about 9 percent lower than the known
value).
81
-------
Bibliography
1. Standard Methods for the Examination of Water and Wastewater, 14th
Edition, American Public Health Association, Washington, D.D., 1976
2. Moghissi, A.A., E.W. Bretthauer, and E.H. Compton, "Separation of Water
from Biological and Environmental Samples for Tritium Analysis," Anal.
Chem., 45:1565, 1973
3. EPA Drinking Water Regulations, Federal Register, Vol. 41, No. 133,
Friday, July 9, 1976, Title 40, Part 141. (See Appendix B in the
Reference Method for Gross Alpha and Gross Beta).
4. Chase, G.D., and J.L. Rabinowitz, Principles of Radioisotope
Methodology, Burgess Publishing Co., Minneapolis, Minnesota, 1967.
5. Bush, E.T., "General applicability of the Channels Ratio Method of
Measuring Liquid Scintillation Counting Efficiencies," Anal. Chem.,
35:1024, 1963
6. 1978 Annual Book of ASTM Standards, Part 31, American Society for
Testing and Materials, Philadelphia, Pennsylvania.
7. Youden, W.J., 1975 "Statistical Techniques for Collaborative Tests,"
Statistical Manual of the AOAC, Association of Official Analytical
Chemists, Washington, D.C. '•
8. Steiner, E.H. 1975. "Planning and Analysis of Results of Collaborative
Tests," Statistical Manual of the AOAC, Association of Official
Analytical Chemists, Washington, D. C.
9. Youden, W. J. 1969. Precision Measurements and Calibration, H.H. Ku,
Editor. National Bureau of Standards, Special Publication 300, Vol. 1.
10. Dixon, W.J. and F.J. Massey, Jr. Introduction to Statistical Analysis,
McGraw-Hill, 1969. ;"
11. Precision, Measurements and Calibration, Statistical Concepts and
Procedures, U.S. Department of Commerce, NBS, Spec. Pub. 300, 1:349-354.
12. Friedlander, G., J.W. Kennedy, and J. Miller, Nuclear and
Radiochemistry, John Wiley and Sons, Inc., New York, New York, 1964.
13. Sodd, V.J., and K.L. Scholz, "Analysis of Tritium in Water; A
Collaborative Study," J. Assoc. Offie. Anal. Chem. 52:1, 1969.
82
-------
SECTION 11
ACTINIDE ELEMENTS IN DRINKING WATER -
THORIUM, URANIUM, NEPTUNIUM, PLUTONIUM, AMERICIUM AND CURIUM
METHOD 907.0
1. Scope and Application
1.1 This method covers the determination of soluble actinide elements
by means of coprecipitation, various chemical separation techniques
and alpha counting. These elements are coprecipitated on ferric
hydroxide, chemically separated by coprecipitation on bismuth phos-
phate and subsequent solvent extraction, and prepared for alpha
counting by coprecipitation on lanthanum fluoride. Alpha counting
can be made by use of an internal proportional counter or,
scintillation counting using zinc sulfide discs. Suspended matter
when present as in the case of raw water supplies, is removed by
filtration prior to analyses.
1.2 Alpha counting techniques such as internal proportional counting or
zinc sulfide scintillation counting preclude the use of internal
tracer yield measurement. This method has been so designed that
chemical yield as determined by tracer measurements has exceeded
85%. Application of this yield factor would result in a maximum
15% bias in the accuracy of the measurement, providing an
overestimated value which is conservative when compared to a
maximum concentration level. Good laboratory techniques must be
followed to consistently achieve these high recoveries.
2. Summary of Method
2.1 The actinide elements are concentrated by coprecipitation on ferric
hydroxide. The ferric hydroxide is dissolved and thorium, neptun-
ium, plutonium, americium and curium, are coprecipitated on bismuth
phosphate, leaving uranium in solution for subsequent solvent
extraction using trioctylphosphine oxide (TOPO). The bismuth phos-
phate is dissolved in strong hydrochloric acid and plutonium and
neptunium are extracted in tri-isooctylamine (TIOA). The thorium
is separated from americium and curium by extraction with TOPO.
All separated and purified elements are coprecipitated on lanthanum
fluoride and alpha counted. Figure 6 illustrates the general
procedural separations.
83
-------
Sample (Acidified)
Fe((
(Th.U.Np,
BiP04 (Th,
Aqu
(Th,A
Aqu
Dryn
H(
La
H
Fe+3,NaOH
"*• Ollpei lldldlll
DH)3
Pu.Am.Cm)
HNO3,Bi+3,70°C,H3PO4
Mp.Pu.Am.Cm,)
HCI,H202,TIOA
'" "**' Oiganic (Np.Pu)
1HCI,NH4I
*
Aqueous (Pu)
Dryness
HCI
eous La
m.Cm) Hll „
*- Superr
TOPO 1 (Disc
Alpha Count
.,..._., j,, Organic (Th)
sous 1 H2SO4
} * O
ess Aqueous (Th)
:| 1 Dryness.HC
"3
F T
LaF3 Alpha
(Discard)
+2
— *- Fe ,(U)
1 TOPO
|> ~ "*" Oi ganic (U)
Aqueous 1 NH OH, (NH,)9CO.,
HCI,La+3,TiCI3,HF
l_i/~»i
...... » ' — 9»- Gupeinalaiil
Ml" LaF3 (Discard)
Alpha Count (U)
ard)
Aqueous
Dryness,HCI,La+3,KF
LaF3 Alpha Count (Np)
rganic (Discard)
,La+3,HF
•*• Supernatant (Discard)
Count (Th)
i"*"3 /nio/^oK/^N
LaF3
Alpha Count (Am.Cm)
Figure 6. Generalized chemical procedure (for actinide elements)
84
-------
3. Significance and Use
3.1 The National Interim Primary Drinking Water Regulation has estab-
lished a Maximum Contaminant Level (MCL) equivalent to an annual
dose of 4 mrem per year. This dose equivalent applies only to
man-made beta and photon emitters. There are no specific maximum
contaminant levels for alpha emitters other than radium-226.
However, in the absence of specific MCL for each of the actinides,
the limit of 15 pCi/1 for gross alpha activity may be inferred.
Maximum Concentration Levels (MCL)
Element
Isotope Critical Organ MPC,yCi/cc MCL,pCi/l
Neptunium
Plutonium
Americium
Curium
237
238
239
240
241
242
243
244
Bone
Bone
Bone
Bone
Kidney
61 Tract
Bone
Bone
3x10-5
5xlO-5
5x10-5
5x10-5
4x10-5
2x10-4
5x10-5
7x10-5
15
15
15
15
15
15
15
15
3.2 This method was developed for the sequential analysis of these
elements from a single sample. The method is responsive to the
requirements of drinking water monitoring as well as being time
responsive and economical.
4. Interferences
4.1 Carbonate and bicarbonate ions interfere in the complete coprecipi-
tation of uranium on ferric hydroxide by forming soluble uranium
complexes. The sample must be boiled or purged with nitrogen gas
under acid conditions to expel carbon dioxide gas from solution.
4.2 Ammonium ions interfere in the complete coprecipitation of neptun-
ium on ferric hydroxide. The use of sodium hydroxide to adjust the
alkalinity results in complete recovery of neptunium. A freshly
prepared solution of sodium hydroxide is recommended as carbon
dioxide is easily absorbed from the air, and will interfere in the
uranium analysis.
4.3 Chelating agents, whether present from natural sources or from
industrial processes, will interfere to varying extent by totally
or partially complexing these actinide elements. When chelating
agents are known to be present in drinking water supplies, the
85
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analyst should resort to alternate methods such as cbprecipitation
from acid solutions.
5. Apparatus - See Appendix D for, Details and Specifications
5.1 Alpha Particle Counter, consisting of either a proportional detec-
tor or a scintillation detector.
5.2 Stainless steel counting planchets
5.3 Plastic ring and disc mounts.
5.4 Filtering Apparatus
5.4.1 Millipore Filter for 47 mm and 25 mm diameter filters.
5.5 Alpha Sensitive Phosphors
5.6 Centrifuge.
5.7 Silica Columns - 2.5 cm I-.D. X 20 cm. Fit one end with rubber
stopper containing an 8 mm O.D. glass tube. Place a wire screen on
the inside of the tube. The filtering column is composed of 3 mm
paper pulp layer, 25 cm^ of silica sand, and covering plug of
glass wool. The top of the column is fitted with a rubber stopper
containing an 8 mm O.D. glass tube. In usage, the column is filled
with water and the top fastened to the siphon tube and the bottom
to the vacuum chamber.
5.8 Glassware
6. Reagents
6.1 Purity of Reagents - Reagent grade chemicals shall be used in all
tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the committee on
analytical reagents of the American Chemical Society. Other grades
may be used provided it is first ascertained that the reagent is
ofsufficiently high purity to permit its use without lessening the
accuracy of the determination.
6.1.1 Purity of Water - Unless otherwise indicated, reference to
water shall be understood to mean conforming to ASTM
Specifications D 1193, Type III.
6.1.2 Radioactive Purity - Radioactive purity shall be such that
the measured radioactivity of blank samples does not exceed
1 cpm.
6.2 Acetone, (CH3)2CO, anhydrous.
6.3 Ammonium hydroxide, 15N[: NffyOH (cone.), sp. gr. 0.9, 56.6%.
86
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6.4
6.5
6.6
6.7
6.8
6.9
Ammonium hydroxide, 1.0N:, Mix 1 volume 15N NH/jOH (cone.) with 14
volumes of water.
Ammonium hydroxide - Ammonium carbonate solution: Dissolve 1.92g
(NH4)2C03 in 100 ml 1.0N NH40H. This solution is 1M in
ammonium hydroxide and 0.2!^ in ammonium carbonate.
Ascorbic Acid,
reagent grade.
Bismuth carrier, (10 mg Bi+3/ml): Dissolve 5.8g
Bi(N03)3.5H20 in 250 ml of Q.5N HN03.
Ethanol, 95%: C2HsOH.
Ferric nitrate carrier, (25 mg Fe+3/ml): Dissolve 50. 4g
Fe(N03)3- 9H20 in 500 ml of 0.5JY HN03.
6.10 Hydrochloric acid, 12N^ HC1 (cone.), sp gr 1.19, 37.2%
6.11 Hydrochloric acid, 8NI: Mix 2 volumes of 12f^ HC1 (cone.) with 1
volume of water.
6.12 Hydrochloric acid - ammonium iodide solution: Dissolve 720 mg
NH4l in 100 ml 8N, HC1. This solution is 8N. in HC1 and 0.05M in
NH^I (Prepare fresh each time) .
6.13 Hydrochloric acid - hydrofluoric acid solution: Mix 8 volumes of
8N^ HC1 with 1 volume of 0.8j^ HF and 7 volumes of water. This
solution is 4N in HC1 and 0.05J^ in HF. Store in plastic bottle.
6.14 Hydrofluoric acid, 29H: HF (cone.), sp. gr. 1.18, 49.0%.
6.15 Hydrofluoric acid, 0.8N; Mix 1 volume of HF (cone.), 49.0% with 35
volumes of water. Store in plastic bottle.
6.16 Hydrogen peroxide, 30%: H202, 30% assay.
6.17 Lanthanum nitrate, (1.0 mg La+3/ml): Dissolve 3.11g
La(N03)3.6H20 in one liter of 0.1N. HMOs.
6.18 Nitric acid, 16N: HMOs (cone.), sp. gr. 1.42, 70.4%.
6.19 Nitric acid, 8N^: Mix 1 volume of 16N^ HN03 (cone.) with 1 volume
of water.
6.20 Nitric acid, IN; Mix 1 volume of 16IN HN03 (cone.) with 15
volumes of water.
6.21 Nitric acid, 0.25N; Mix 1 volume IN^ HN03 with 3 volumes of water.
6.22 Nitrogen, gas. C.P.
87
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6.23 Phenolphthalein indicator (5 g/1): Dissolve 0.5g phenolphthalein
in 50 ml ethanol (95%) and dilute to 100 ml with water.
6.24 Phosphoric acid, UN; Mix 1 volume of 44j^ 1^04 (cone.)
(sp.gr. 1.70) with 3 volumes of water.
6.25 Silica sand - granular, 80-120 mesh.
6.26 Sodium hydrogen sulfate - isulfuric acid solution: Dissolve lOg
NaHS04 in 100 ml of water and then carefully add 100 ml of 361N
H2S04 (cone.) while stirring. This solution contains 5g
NaHS04 per 100 ml of 18N[ H2S04.
6.27 Sodium hydroxide, 6N;. Dissolve 48g NaOH pellets in 125 ml of
water. Cool and dilute to 200 ml with water. (Prepare fresh as
NaOH will absorb C0£ from the air and interfere with the uranium
analysis).
6.28 Sodium hydroxide, O.IN^ - Dissolve 4g NaOH pellets in 800 ml water
in a one liter volumetric flask and dilute to volume. Standardize
against potassium acid phthalate.
6.29 Sulfuric acid, 36N:
(cone.), sp. gr. 1.84, 96.0%.
6.30 Sulfuric acid, 0.6IN: Mix 1 volume of 36J^ H2S04 (cone.) with 59
volumes of water.
6.31 Titanium trichloride,
20%
6.32 Triisooctylamine (TIOA) (1+9): Mix 1 volume of TIOA with 9 volumes
of xylene. Wash this reagent twice with 0.5N HN03 and once with
water at a phase ratio of 2 volumes of TIOA and 1 volume acid and
water, respectively.
6.33 Tri-octyl phosphine oxide (TOPO) (0.1M) • Dissolve 19. 3g TOPO in 500
ml heptane.
7. Sample Handling and Preservation -.(See Sec. 3, Method 900.0)
7.1 Collect the samples in accordance with ASTM D 3370, Standard
Practices for Sampling Water.
7.2 To ensure continued solubility of the sample constituents, adjust
the pH of the sample to ^ 2 with 1IN
7.3 If the sample is taken from a raw water supply, it must be filtered
as soon as possible after collection to minimize adsorption of the
soluble constituents onto the suspended matter, and then acidified
to maintain their solubilities.
88
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8. Procedure
8.1 Coprecipitation
8.1.1
8.1.2
8.1.3
8.1.4
8.1.5
8.1.6
8.1.7
8.1.8
8.1.9
Measure a volume of finished drinking water or filtered raw
water from 1 to 15 liters into an appropriately sized
container. Acidify with 161^ HNOa (cone.) at a rate of 5
ml per liter and mix.
Add ferric nitrate solution at a rate of 1 ml per liter for
the first 6 liters and 0.5 ml per liter thereafter, and mix.
Add 10 drops of the phenolphthalein indicator and if sample
volume is small (< 4 liters), heat to boiling with stirring
to remove carbon dioxide. If sample volume is large
( > 4 liters), purge the solution with nitrogen gas for 30
minutes at a purge rate to simulate a rolling boil. (A
glass fritted filter stick is recommended to disperse the
gas stream).
Add sufficient 6N NaOH until alkaline to phenolphthalein.
Continue the stirring or nitrogen gas purge for 30
minutes. Remove stirring bar or nitrogen purge system, and
allow the precipitate to settle for 1 hour.
With gentle vacuum, siphon and filter the cleared supernate
through the silica column, being careful not to disturb the
precipitate.
Collect the settled precipitate in a 250 ml centrifuge
bottle centrifuge and discard the supernate.
Add 100 ml IN^ HNOa to the precipitating vessel to
dissolve any remaining ferric hydroxide.
Pass this solution slowly through the silica column to
dissolve any filtered ferric hydroxide.
Add this acid effluent to the 250 ml centrifuge bottle
containing the bulk of the ferric hydroxide.
8.1.10 Warm to effect solution, cool, and estimate volume.
8.1.11 Transfer T.O ml of the solution to a 125 ml Erlenmeyer
flask containing 25 ml of water and 3 drops phenolphthalein.
8.1.12 Titrate with the standardized 0.1 N^ NaOH solution to the
phenolphathalein end point and determine the normality of
the solution.
8.1.13 Dilute remaining solution with water until the acid
concentration is Q.25N in HMOs. If solution is less than
89
-------
400 ml, add sufficient 0.25]^ HNOs to bring to 400 ml
volume. Filter through a 47 mm 0.45 y millipore filter to
remove any silica fines. Discard filter.
8.1.14 Add 5 ml bismuth carrier, and sufficient ascorbic acid to
concentration of 0.2% and mix.
8.1.15 Heat to 7QQC and while stirring, add 4 ml 11N_ HsPO^
8.1.16 Remove from heat and agitate slowly for 30 minutes. Remove
stirring bar and allow to settle.
8.1.17 Filter precipitate on a 47 mm diameter Millipore filter
(0.45 u) and wash twice with 10 ml 0.25j^ HNOs. Save both
the filtrate and precipitate.
8.2 Uranium Analysis
8.2.1
Transfer the filtrate from Step 8.1.17 to a one-liter
separatory funnel. Rinse the container with a minimum of
0.25N[ HNOs, adding rinsings to the separatory funnel.
8.2.2
Increase the HNOs concentration to IN^ by adding
sufficient 8N HNO.
8.2.3 Add trioctylphosphine oxide solution (TOPO) equal to 1/10
the aqueous volume and extract by shaking vigorously for
four minutes.
8.2.4 Allow the phases to separate for 10 minutes. Drain the
aqueous phase into a- beaker and the organic phase into a
125 ml separatory funnel.
8.2.5 Transfer the aqueous phase back to the one-liter separatory
funnel and add TOPO solution equal to 1/20 of the aqueous
volume. Extract by shaking vigorously for 4 minutes.
8.2.6 Allow the phases to separate for ten minutes. Discard the
aqueous phase and transfer the organic phase into the 125
ml separatory funnel.
8.2.7 Wash the combined organic phases with 15 ml IN^ HNOs,
discarding the wash solution.
8.2.8 Add 25 ml ammonium hydroxide-ammonium carbonate solution
and carefully shake, relieving the evolved C02 gas.
Shake vigorously for 2 minutes.
8.2.9 Allow the phases to separate for 10 minutes and drain the •
aqueous phase into a 100 ml beaker.
8.2.10 Repeat steps 8.2.8 and 8.2.9, discarding the organic phase.
90 !
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8.2.11 Cover the beaker with a ribbed watch glass and evaporate
to dryness over moderate heat.
8.2.12 Remove from heat and add 5 ml 16N. HN03 and 1 ml 5%
NaHS04 and slowly evaporate to dryness.
8.2.13 Place in muffle furnace and heat to 500°C to remove all
organics. Cool and continue with Section 8.6.
8.3 Plutonium and Neptunium Analysis
8.3.1 Transfer the membrane filter containing the precipitate
(Step 8.1.17) to a 40 ml centrifuge tube.
8.3.2 Add 20 ml 8N HC1 and dissolve precipitate.
8.3.3 Add 5 drops of 30% hydrogen peroxide, and heat in a water
bath until effervescence ceases, using occasional stirring.
8.3.4 Cool and transfer the solution to a 125 ml separatory
funnel. Wash the centrifuge tube twice with 15 ml 8N HC1,
and add the washings to the separatory funnel.
8.3.5 Add 25 ml tri-isooctylamine solution (TIOA) and shake
vigorously for 2 minutes.
8.3.6 Allow the phases to separate and drain the aqueous phase
8.3.7
8.3.8
8.3.9
into a second 125 ml separatory funnel .
Wash the organic phase by shaking with 10 ml
HC1.
Allow the phases to separate and combine the wash into the
second separatory funnel. Retain this aqueous phase for
further analyses. (Section 8.4)
Add 10 ml hydrochloric acid - ammonium iodide solution to
the organic phase and shake for 2 minutes.
8.3.10 Allow the phases to separate and drain the aqueous phase
into a 30 ml beaker.
8.3.11 Repeat steps 8.3.9 and 8.3.10.
8.3.12 Add 1 ml of the acidified NaHS04 solution and evaporate
the combined aqueous solutions to dryness. Place in muffle
furnace and heat to 500°C to remove organics. Save for
Plutonium mounting and counting. (Section 8.6.)
8.3.13 Add 10 ml of the hydrochloric acid - hydrofluoric acid
solution to the organic phase and shake for 2 minutes.
91
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8.3.14 Allow the phases to separate and drain the aqueous phase
into a 30 ml beaker.
8.3.15 Repeat steps 8.3.13 and 8.3.14.
8.3.16 Add 1 ml of the acidified NaHSCty solution and evaporate
the combined aqueous solutions to dryness. Place in muffle
furnace and heat to 500°C to remove organics. Save for
neptunium mounting and counting. (Section 8.6.)
8.4 Thorium, Americium and Curium Analyses
8.4.1 To the aqueous phase resulting from step 8.3.8, add 20 ml
TOPO and shake for 3 minutes.
8.4.2 Allow the phases to separate and drain aqueous phase into a
125 ml separatory funnel.
8.4.3 Wash the organic phase by shaking with 10 ml 8j^ HC1, adding
the wash to the 125 ml separatory funnel. Save the aqueous
phase for further analyses. (Section 8.5)
8.4.4 Add 20 ml 0.6IN H2S04 to the organic phase and shake for
2 minutes.
8.4.5 Allow the phases to separate and drain the aqueous phase
into a 50 ml beaker.
8.4.6 Repeat steps 8.4.4 and 8.4.5 and discard organic phase.
8.4.7 Add 1 ml of the acidified NaHS04 solution and evaporate
combined acid extracts to dryness. . Place in"muffle furnace
and heat to 500°C to remove organics. Save for sample
mounting and counting. (Section 8.6).
8.5 Americium and Curium
8.5.1 To the solution remaining from step 8.4.3, add 20 ml
heptane.
8.5.2 Extract by shaking for 1 minute and allow the phases to
separate.
8.5.3 Drain the aqueous phase into a 100 ml beaker.
8.5.4 Wash the organic phase by shaking with 10 ml water.
8.5.5 Combine the water wash into the 100 ml beaker. Discard the
organic layer.
8.5.6 Evaporate the contents of the 100 ml beaker to dryness.
92
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8.5.7 Place beaker in a 500°C muffle furnace for one hour.
8.5.8 Remove from furnace, cool and save for sample preparation
and counting. (Section 8.6.)
8.6 Sample Mounting (Lanthanum fluoride coprecipitation) ,
8.6.1 To all separated.and purified fractions remaining from
steps 8.2.13, 8.3.12, 8.3.16, 8.4.7, and 8.5.8, add 1 ml
12_N HC1 (cone.).
8.6.2 Dilute to 10 ml and add 1.0 ml lanthanum carrier solution
and for uranium analyses only, add 0.2 ml 20% TiCl3.
8.6.3 Add 0.5 ml HF (cone.), stir well and allow to stand for 30
minutes.
8.6.4 Filter through a 25 mm diameter millipore filter (0.2y pore
size).
8.6.5 Wash one time each with 10 ml portions of water and ethanol.
8.6.6 Prepare for sample counting. (Section 8.7.)
8.7 Sample Counting
8.7.1 Internal proportional counting or scintillation counting as
described in Sections 5.1.1 and 5.1.2.
8.7.1.1 Transfer the nucleopore filter to the center of a
stainless steel disc of appropriate diameter,
previously treated with a thin coating of rubber
cement and containing one drop each of acetone
and ethanol.
8.7.1.2 Allow the excess acetone and ethanol to evaporate.
8.7.1.3 Dry and alpha count.
8.7.2 Scintillation counting assembly as described in Section
5.1.4.
8.7.2.1 Carefully center the nucleopore filter on a
plastic disc, lightly coated with rubber cement.
8.7.2.2 Cover with an alpha sensitive phosphor djsc by
. placing the sensitized side in direct contact
with the sample filter.
8.7.2.3 Place a sheet of mylar film over entire disc and
retain in place with the plastic ring. Trim away
excess mylar.
93
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8.7.2.4 Place the mounted sample on the photomultiplier
tube with the mylar cover in direct contact with
the tube.
8.7.2.5 Alpha count.
9. Calibration
9.1 General guidance information may be found in ASTM D 3648, Standard
Practices for the Measurement of Radioactivity.
9.2 Counting standards to calibrate instrumental response to alpha
particles are prepared from calibrated standards which are NBS
certified or traceable to NBS certification.
9.3 Chemical preparation of counting standards must follow the same
procedures as prescribed in Section 8.6 and 8.7.
9.4 Counter efficiency, E, is then determined by counting the
calibration source for sufficient time to minimize counting error
and is expressed as:
E =
D - B
G
where:
D = observed count rate, cpm,
B = background count rate, cpm, and
G = activity of calibration source, dpm.
10. Calculation
10.1 The results of analysis, A, are expressed in picocuries per
liter. This unit is useful for direct comparison to the maximum
concentration level as determined from the National Interim Primary
Drinking Water Regulations.
A =
D - B
E x 2.22 x 0.85 x V
where:
D = observed count rate, cpm,
B = background count rate,- cpm,
E = counter efficiency
2.22*= conversion factor for dpm/pCi
0.85 = chemical yield, and
V = sample volume in liters
94
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11. Precision and Accuracy
11.1 The U.S. Environmental Monitoring Systems Laboratory in Las Vegas,
Nevada, is in the process of conducting a single laboratory study
to determine the accuracy and precision of this test procedure.
Bibliography
1. Carl T. Bishop, et. al. "Tentative Method for the Determination of
Plutonium-239 and Plutonium-238 in Water," MLM-MU-76-69-0002, Sept. 1976.
2. G. A. Burney and R. M. Harbour, "Radiochemistry of Neptunium,"
NAS-NS-3060, Dec. 1974.
3. George H. Coleman, "Radiochemistry of Plutonium," NAS-NS-3058, Sept.
1965.
4. James E. Grindler, "Radiochemistry of Uranium," NAS-NS-3050, March 1962.
5. E. K. Hyde, "Radiochemistry of Thorium," NAS-NS-3004, January 1960.
6. H. L. Krieger and B. Jacobs, "Analysis of Radioactive Contaminants in
By-Products from Coal-Fired Power Plant Operations," EPA-600/4-78-039,
July 1978.
7. Fletcher L. Moore, "Liquid-Liquid Extraction with High-Molecular-Weight
Amines," NAS-NS-3101, December 1960.
8. R. A. Pennamen and T. K. Keenan, "Radiochemistry of Americium and
Curium, " NAS-NS-3006, January 1960.
9. T. G. Scott and S. A. Reynolds, "Determination of Plutonium in
Environmental Samples. Part II. Procedures." Radiochem. Radioanal.
Letters, Vol. 23, p. 275 fl. (1975).
10. J. C. White and W. J. Ross, "Separations by Solvent Extraction with
Tri-n-octylphosphine Oxide," NAS-NS-3102, February 1961.
11. 1979 Annual Book of ASTM Standards, Part 31, American Society for
Testing and Materials, Philadelphia, Pa. (1979).
12. R. Lieberman and A.A. Moghissi, "Coprecipitation Techniques for Alpha
Spectroscopic Determination of Uranium, Thorium and Plutonium," Health
Physics, 15, 359 (1968).
95
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SECTION 12
URANIUM IN DRINKING WATER -
RADIOCHEMICAL METHOD
METHOD 908.0
1. Scope and Application
1.1 This method covers the measurement of total uranium alpha particle
activity in drinking water. Most drinking water sources,
especially ground water sources, contain soluble carbonates and
bicarbonates which complex and keep uranium in the water in
solution.
1.2 Uranium isotopic abundances in drinking water sources are apt to be
present in ratios different from the ratios in the deposits from
which the uranium entered the water sources. The two predominant
natural alpha emitting isotopes of uranium are uranium-234 and
uranium-238. Uranium-238 is the predominant mass abundant isotope;
greater than 99% compared to about 0.006% for uranium-234,,
However, uranium-234 has a specific activity for alpha particle
emission that is 1.8 x 10^ times greater than that of
uranium-238. For an equilibrium condition, the activity of the
uranium-234 is equal to that of the uranium-238. Therefore, the
uranium mass concentration in water is not related to the alpha
particle activity of the water.
1.3 The Drinking Water Regulations under the Safe Drinking Water Act,
PL 93-523, require a measurement of uranium for drinking water
samples that have a gross alpha activity greater than 15 pCi/1. A
mass uranium concentration measurement of a water samp,le cannot be
converted to uranium alpha activity without first analyzing for
isotopic abundances. Therefore, a method such as this one is
needed to determine the total uranium alpha activity of the sample,
without doing an isotopic uranium analysis.
2. Summary of Method
2.1 The water'sample is made acid by adding HC1 and the sample is
boiled to eliminate carbonate and bicarbonate ions. Uranium is
coprecipitated with ferric hydroxide and separated from the
sample. The uranium is then separated from other radionuclides
which were carried down with the ferric hydroxide by dissolving the
hydroxide precipitate in 8N HC1, putting the solution through an
96
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anion exchange column, washing the column with 8^ HC1, and finally
eluting the uranium with O.vlN/HCl. The uranium eluate is evapo-
rated and the uranium chemical form is converted to nitrate. The
residue is transferred to "a stainless steel planchet, dried,
flamed, and counted for alpha particle activity.
2.2 Uranium recovery is determined with blank samples spiked with known
amounts of uranium and taken through the procedure as a regular
sample.
2.3 Counting efficiency is determined by transferring measured aliquots
of an uranium standard to a planchet, diluting with 6-8 ml of a
1 mg/ml HI03 solution in 4j\[ HN03, evaporating to dryness,
flaming the planchet, and counting in an alpha counter.
3. Sample Handling and Preservation.
3.1 Although carbonate ions in a water sample will help to keep uranium
in solution, the addition of extra carbonate or bicarbonate ions to
the sample as a preservative is not recommended because an
increased carbonate concentration in the sample may cause some
precipitation. Therefore, it is recommended that samples be
preserved with HC1 to pH 2 at the time of collection.
3.2 A sample size of at least 1 liter should be collected for uranium
analysis.
4. Interferences
4.1 The only alpha-emitting radionuclide that may come through the
chemistry and cause interference would be protactinium-231.
However, protactinium-231 results from the decay of uranium-235, a
low abundance natural isotope of uranium, and would therefore cause
only a very small interference.
4.2 Since uranium is a naturally occuring radionuclide, reagents must
be checked for uranium contamination by analyzing a complete
reagent blank by the same procedure as used for the samples.
5. Apparatus - See Appendix D for details and specifications
5.1 Gas-flow proportional counting system or
5.2 Scintillation detection system
5.3 Glassware
5.4 Electric hot plate
5.5 Ion exchange column: approximately 13 mm (i.d.) x 150 mm long with
a 100 ml reservoir.
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5.6 Stainless steel counting planchets, 2 inch diameter by 1/4 inch
deep.
5.7 Millipore filter apparatus, 47 mm.
Reagents
6.1 All chemicals should be of reagent grade or equivalent whenever
they are commercially available.
6.2 Ammonium hydroxide, 6N: Mix 2 volumes 15]^ NlfyOH (cone.) with 3
volumes of water (carTJonate-free.)
6.3 Anion exchange resin - Strongly basic, styrene, quaternary ammonium
salt, 4% cross! inked, 100-200 mesh, chloride form (such as Dowex
1x4, or equivalent).
6.4 Ferric chloride carrier, 20 mg Fe+3/ml: Dissolve 9.6g of
FeCls.6H20 in 100 ml of 0.5 H HC1.
6.5 Hydriodic acid: HI (cone.), sp. gr. 1.5, 47%.
6.6 Hydrochloric acid, 12N: HC1 (cone.), sp. gr. 1.19, 37.2%.
6.7 Hydrochloric acid, 8H: Mix 2 volumes 12f^ HC1 (cone.) with 1 volume
of water.
6.8 Hydrochloric acid, 6j^: Mix 1 volume 12^ HC1 (cone.) with 1 volume
of water.
6.9 Hydrochloric acid, 0.1N_: - Mix 1 volume 0.5j^ HC1 with: 4 volumes of
water.
6.10 lodic acid, 1 mg/ml: Dissolve 100 mg HI03 in 100 ml 4N^
6.11 Nitric acid, 16N.: HNOs (cone.), sp. gr. 1.42, 70.4%.
6.12 Nitric acid, 4N^: Mix 1 volume 16N^
water.
6.13 Sodium hydrogen sulfite,
(cone.) with 3 volumes of
6.14 Sodium hydrogen sulfite, 1% in HC1: Dissolve Ig NaHSOs in 100 ml
6]|HC1.
Calibrations
7.1 Determine a counting efficiency (E), for a known amount of standard
uranium (about 1000 dpm) evaporated from a 6-8 ml volume of a 1
mg/ml HI03 solution in a 2 inch diameter stainless steel
planchet. If the standard solution is an HC1 solution, then
aliquot portions of that solution must be converted to
98
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nitrate/ HN03 solutions, eliminating all chloride ions from the
solutions. This can be done by three successive evaporations after
adding 5 ml portions of 16N HN03 to aliquot portions of the
standard in small beakers "("avoiding dry baking of the evaporated
residue). The final solutions of the standard aliquots are made by
adding 2 ml 4IN HMOs solution to the third evaporated residues.
Transfer the uranium standard aliquot solutions to 2 inch diameter
stainless steel planchets.
Complete the transfer by rinsing the beakers two times with 2 ml
portions of 4j^ HN03 and evaporate to dryness. Flame the
planchets and count for at least 50 minutes for alpha particle
activity. A reagent blank should be run along with the standard
aliquots and should be alpha counted.
Efficiency, cpm/dpm,(E) =
where:
A - B
A = gross cpm for standard
B = cpm for instrument background
C = dpm of standard used.
7.2 A uranium recovery factor R, is determined by the following
procedure: Spike one liter tap water samples with aliquots of
uranium standard solution (500-1000 dpm per sample). Take these
spiked samples and a tap water blank through the entire procedure
and count the separated and evaporated uranium for alpha particle
activity.
Recovery factor, (R) =
where:
(F - B)
CE
C = dpm of uranium standard added
F = gross cpm of spiked sample
B = cpm of reagent blank
E = efficiency factor, cpm/dpm
8. Procedure
8.1 Measure the volume of approximately one liter of the water sample
to be analyzed.
8.1.2 If the sample has not been acidified, add 5 ml 12j^ HC1. and
1 ml ferric chloride carrier.
8.1.3 Mix the sample completely and use pH paper to check the
hydrogen-ion concentration. If the pH is > 1, add 12f^ HC1
until it reaches this value.
99
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8.1.4 Cover with a watch glass and heat the water sample to
boiling for 20 minutes.
8.1.5 The pH must be checked again after boiling and if it is > 1,
HC1 must be added to bring the pH back to 1.
8.1.6 While the sample is still boiling gently add 6N_ NH/jOH to
the sample from a polyethylene squeeze bottle with the
bottle delivery tube inserted between the watch glass and
the pouring lip of the beaker. The boiling action of the
sample provides sufficient stirring action. Add 6N NlfyOH
until turbidity persists while boiling continues; Then add
an additional 10 ml, (estimated addition from the squeeze
bottle).
8.1.7 Continue to boil the sample for 10 minutes more; then set it
aside for 30 minutes to cool and settle.
8.1.8 After the sample has settled sufficiently, decant and filter
the supernate through a 47 mm 0.45 micron membrane filter,
using the larger millipore filtering apparatus.
8.1.9 Slurry the remaining precipitate, transfer to the filtering
apparatus and filter with suction.
8.1.10 Place the filtering apparatus over a clean 250 ml filtering
flask, add 25 ml 8j^ HC1 to dissolve precipitate, and filter
the solution.
8.1.11 Add another 25 ml 8j^ HC1 to wash the filter, and then filter.
8.1.12 Transfer solution to the 100 ml reservoir of the ion
exchange column.
8.1.13 Rinse the side arm filtering flask twice with 25 ml portions
of SN^HCl. Combine in the ion exchange reservoir.
8.2 Anion Exchange Separation
8.2.1 Prepare the column by slurrying the anion exchange resin
with 8t^ HC1 and pouring it onto a column of about 13 mm
inside diameter. The height of the resin bed should be
about 80 mm.
8.2.2 Pass the sample solution through the anion exchange resin
column at a flow rate not to exceed 5 ml/min.
*
8.2.3 After the sample has passed through the column, eTute the
iron (and plutonium if present) with 6 column volumes of 8f[
HC1 containing 1 ml 47% HI per 9 ml of 8H HC1 (freshly
prepared).
100
-------
8.2.4 Wash the column with an additional two column volumes of 8N
HC1.
; ."'. , \
8.2.5 Elute the uranium with six column volumes of O.lj^ HC1.
8.2.6 Evaporate the acid eluate to near dryness and convert the
residue salts to nitrates by three successive treatments
with 5 ml portions of 161^ HN03, evaporating to near
dryness each time.
8.2.7 Dissolve the residue (may be very little visible residue) in
2 ml 4N^ HN03.
8.2.8 Transfer the residue solution, using a Pasteur pipet, to a
marked planchet, and complete the transfer by rinsing the
sample beaker three times with 2 ml portions of W HN03.
8.2.9 Evaporate the contents in the planchet to dryness, flame to
remove traces of HI03, cool, and count for alpha particle
activity.
8.3 Column Regeneration
8.3.1 Pass three column volumes of 1% NaHSOs in 6j^ HC1 through
the column.
8.3.2 Pass six column volumes of 6_N HC1 through the column.
8.3.3 Pass three column volumes of water through the column.
8.3.4 Pass six column volumes of 8N^ HC1 through the column to
equilibrate and ready the resin for the next set of samples.
9. Calculations
Uranium alpha activity, pCi/1
where:
(S - B) x 1000
2.22 x E R V
S = gross cpm for sample
B = cpm of reagent blank
V = volume of sample used, ml
E = efficiency, cpm/dpm
R = recovery factor
2.22 = conversion factor for dpm/pCi
10. Precision and Accuracy
In a single laboratory test of this method, a stock uranium solution was
prepared using tap water and spiked with an NBS uranium standard. The
calculated concentration was 26.7 pCi/1. This stock solution was
acidified with HC1 as a preservative. Nine 1-liter aliquots were
101
-------
withdrawn and the procedure tested. Individual results were 22.4, 22.5,
24.0, 25.9, 26.9, 26.5, 24.6, 25.7 and 23.9 pCi/1. The average
concentration was 24.7 pCi/1 with a standard 'deviation of 1.7 pCi/1.
From these data, the method shows a negative 7.4% bias and a precision
of _+ 6.7% without the correction of the recovery factor.
References
Bishop, C. T., et.al. "Radiometric Method for the Determination of
Uranium in Water," EPA 600/7-79-093, EMSL-LV, April 1979.
Edwards, K. W. "Isotopic Analysis of Uranium in Natural Waters by Alpha
.Spectrometry," Radiochemical Analysis of Water, Geological Survey Water
- Supply Paper 1696-F, U.S. Government Printing Office,
Washington, D.C., 1968.
102
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SECTION 13
URANIUM IN DRINKING WATER -
FLUOROMETR1C METHOD
METHOD 908.1
1. Scope and Application
1.1
1.2
The method covers the determination of soluble uranium in waters at
concentrations greater than 0.1 yg/1. There is no upper limit,
since waters whose uranium concentrations exceed the upper limit of
the measurement range need only be diluted to be within this range.
Uranium is present in surface and ground waters at concentrations
generally less than 20 yg/1. This method is applicable for the
monitoring of water discharges from industries related to the
uranium fuel cycle. Since the method measures the mass of uranium,
it is applicable to the assessment of chemical toxicity. The
method can be indirectly used for the assessment of radiation
effects if the isotopic composition is known or measured.
2. Summary of Method
Uranium is concentrated by coprecipitation with aluminum
phosphate. The aluminum phosphate is dissolved in dilute nitric
acid containing magnesium nitrate as a salting agent and the
coprecipitated uranium is extracted into ethyl acetate. After the
ethyl acetate is removed by evaporation, the extracted residue is
dissolved in nitric acid and diluted to volume in a small
volumetric flask. Aliquots are transferred to each of two fusion
dishes and dried. To one dish is added a known mass of uranium
(0.1 yg) and dried. Flux containing sodium fluoride is added to
each of the dishes, fused at a prescribed temperature, cooled and
read in a fluorometer. The use of the standard addition technique
corrects for any interference that may coextract with uranium.
Interferences
3.1 The fluorescence of uranium in a fluoride matrix can be quenched or
enhanced by either cations or anions. When uranium is present in
low concentration (less than 20 yg/1) these interferences can be
eliminated by the coprecipitation of uranium on aluminum phosphate
and subsequent uranium extraction into ethyl acetate.
103
-------
3.2 Carbonate ions form soluble uranium complexes which prevent the
coprecipitation on aluminum phosphate. Carbonates are removed by
acidification and expelled from solution as volatile carbon dioxide.
4. Apparatus - See Appendix D for details and specifications
4.1 Fluorometer, Jarrell-Ash or equivalent.
4.2 Dish forming die, Cat. No. 26100, Fisher'Scientific
4.3 Fusion dish blanks - Gold or Platinum 0.015" thickness x 0.75"
diameter.
4.4 Muffle furnace - controlled temperature.
4.5 Micro!iter pipette - 100 yl.
4.6 Glassware
5. Reagents
5.1 Purity of Reagents - Reagent grade chemicals shall be used in all
tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the committee on
analytical reagents of the American Chemical Society. Other grades
may be used provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
accuracy of the determination.
5.2 Purity of Water. Unless otherwise indicated, reference to water
shall be understood to mean conforming to ASTM Specification D
1193, Type III.
5.3 Aluminum nitrate, 0.08M: Dissolve 15g A1(N03)3.9H20 in 500
ml of water.
5.4 Ammonium hydroxide, 15N; NH40H (cone.) sp.gr. 0.90, 56.6%.
5.5 Diammonium hydrogen phosphate 0.11M:' Dissolve 7.26g
in 500 ml water.
, 45.5 parts
5.8 Magnesium nitrate, 3.5M: Dissolve 449g
Mg(N03)2.6HeO in 350 ml water containing 32 ml 16N^ HMOs.
Warm if necessary to dissolve. Cool and dilute to 500 ml.
5.9 Nitric acid, 16N; HNOs (cone.), sp. gr. 1.42, 70.4%.
5.6 Ethyl acetate, CHsCOOCgHs, reagent grade
5.7 Flux: Mix together 9 parts NaF, 45.5 parts
by weight in a ball mill.
104
-------
5*10 Nitric acid, 0.1N; Mix 1 volume 16N HNOs (cone.) with 159 volumes
of water.
5.11 Phenolphthalein (5g/l): Dissolve 0.5g phenolphthalein in 50 ml
ethanol (95%) and dilute to 100 ml with water.
5.12 Sodium thiosulfate, Na2$20s: crystal
5.13 Uranium standard stock solution. 1000 pg/ml. Weigh out 0.1179g
UgOs into a 100 ml beaker and dissolve in 10 ml 1J^ HNOs,
warming on a hot plate as required. Transfer to a 100 ml
volumetric flask with water and dilute to volume.
5.14 Uranium standard solution, 10 yg/1. Transfer 5.0 ml of the 1000
ug/1 uranium solution to a 500 ml volumetric flask and dilute to
volume with O.lh
5.15 Uranium standard solution, 1 yg/1. Transfer 10.0 ml of. the 10 yg/1
uranium solution to a 100 ml volumetric flask and dilute to volume
with 0.1N HNOs.
5.16 Uranium standard solution, 0.1 yg/1: Transfer 10.0 ml of the 1.0
yg/1 uranium solution to a 100 ml volumetric flask and dilute to
volume with 0.1IN HNOs.
6. Procedure
6.1 Direct Analysis (Samples greater than 20 yg/1).
6.1.1 Transfer two 100 yl aliquots of the filtered sample to each
of two gold dishes and evaporate to dryness under heat lamps.
6.1.2 To one of the gold dishes add 100 yl of a uranium standard
(0.1 yg/ml for samples 20-400 yg/1 or 1.0 yg/ml for samples
greater than 400 yg/1).
6.1.3 Evaporate to dryness under a heat lamp.
6.1.4 Using a balance sensitive to at least one milligram, weigh
out 400 +4 mg flux into each of the two gold dishes.
6.1.5 Prepare a blank flux sample by weighing out 400 + 4 mg flux
into a clean gold dish.
6.1.6 Place the three gold dishes into a stainless steel support
and place in a preheated muffle furnace at 625°C for 15
minutes.
6.1.7 Remove from furnace and cool in a desiccator for 30 minutes.
6.1.8 Read in a fluorometer as directed in Section 7.0.
105
-------
6.2 Coprecipitation (Samples less than 20 ug/1).
6.2.1 Measure a 1 liter aliquot of filtered water into a 1500 ml
beaker.
6.2.2 Acidify with 2 ml 16N HN03 (This may be omitted if sample
was previously acidified for preservation). [
6.2.3 Add 5 ml each of the aluminum nitrate and diammonium
hydrogen phosphate solutions and mix.
6.2.4 If sample was chlorinated as in the case of a drinking water
sample, add one crystal of sodium thiosulfate and stir.
6.2.5 Heat to near boiling to expel dissolved carbon dioxide gas.
6.2.6 Add 5 drops of phenolphthalein indicator and neutralize to
the pink end point using 15]^ NltyOH.
6.2.7 Lower the heat and digest sample for 30 minutes.
6.2.8 Remove from heat, cool, and settle for one hour.
6.2.9 Decant and filter the clarified supernate through a 47 mm
glass fiber filter, transferring the settled precipitate at
the very end.
6.2.10 Wash beaker and filter with small portions of water.
6.2.11 Fold filter into thirds (similar to the folding of a letter)
and transfer to a 50 ml screw cap centrifuge tube.
Note: If some of the precipitate remains on the inside
edges of the filtering apparatus gently wipe with
the folded filter before transferring to the
centrifuge tube.
6.2.12 Add 15 ml 3.5M Mg(NOs)2.6H20 to the centrifuge tube to
dissolve the aluminum phosphate.
6.2.13 Add 10 ml ethyl acetate, securely cap the tube and mix
thoroughly for one minute using a vortex mixer,
6.2.14 Centrifuge at 2000 rpm for 5 minutes.
6.2.15 Using a Pasteur transfer pipette, transfer about 9 ml of the
top layer (ethyl acetate) to a 30 ml beaker.
6.2.16 Repeat steps 6.2.13 to 6.2.15 two more times.
6.2.17 Slowly evaporate the combined ethyl acetate fractions to
dryness.
106
-------
6.2.18 Add 1 ml 161^ HMOs and dissolve residue.
v ....; "
6.2.19 Using the same Pasteur pipette, transfer the nitric acid to
a 5 ml volumetric flask.
6.2.20 Add 1 ml of water to the beaker, wash down the sides of the
beaker using the pipet, and transfer to the 5 ml volumetric
flask.
6.2.21 Repeat 6.2.20 two more times.
6.2.22 Gently mix, cool, dilute to volume with water, and shake
thoroughly.
6.2.23 Proceed with steps 6.1.1 through 6.1.8, using the 1.0 yg/ml
uranium standard.
7. Fluorometric Determination
7.1 Place the gold dish containing the sample plus the uranium spike
into the fluorometer.
7.2 Following the manufacturer's suggested technique, adjust the
voltage to maximize the reading such as full scale deflection.
7.3 Remove the spiked sample, insert the background sample and adjust
the null voltage to read zero.
7.4 Repeat steps 7.2 and 7.3 until no'more voltage adjustments are
required.
7.5 Insert the gold dish containing the sample only and record the
output. •
8. Calculations
8.1 The results of the analysis are expressed in micrograms per liter
and are calculated as follows:
Uranium, pg/1 =
where:
5
R
L • R
b
s ~
ss
X
Rb
- RS
V
1
J
X
Rs = Reading of the sample
Rb = Reading of the blank
Rss = Reading of the spiked sample
a = Mass of the uranium spike, ug
b = Aliquot size of the concentrate, ml
V = Initial sample size in liters
5 = Volume of the volumetric flask, ml
107
-------
8.2 In the case where the uranium concentration is greater than 20 yg/1
and no concentration procedure is performed, the factors "5" and
"b" of the above equation are deleted.
9. Precision and Accuracy
9.1 Precision •>
9.1.1 The single laboratory precision of the method was evaluated
by replicate analyses of a spiked uranium sample at the 10
ug/1 concentrltion. The standard deviation is calculated
from the equation:
S =
N - 1
1/2
where:
N
= summation of the squares of the
individual results
= square of the summation of the individual
results ,
= number of results
9.1.2 The coefficient of variation (CV) is calculated from the
equation.
100 S
CV =
X
where:
S = standard deviation from the above equation
X = mean value of the individual results
9.1.3 Using the above equations, the coefficient of variation has
been estimated as _+ 15%.
9.2 Accuracy or Bias
9.2.1 The single laboratory accuracy of the method was evaluated
over the uranium concentration range of 1-10 yg/'L The
percent accuracy was calculated from the equation::
% Accuracy =
10°
Xt
108
-------
where:
Xf = determined value of individual sample
Xt = known value of the sample
9.2.2 The average percent accuracy, A, is calculated from the
equation:
% Accuracy
N
where:
9.2.3
£% Accuracy = Summation of the individual
accuracy determination
N = number of determinations
The single laboratory evaluation of the average percent
accuracy is estimated to be + 104%.
References
1. Barker, F.B., et al., "Determination of Uranium in Natural Waters,"
Geol. Survey Water Supply Paper, 1696-C (1965).
2. Blanchard, R., "Uranium Decay Series Disequilibrium in Age Determination
of Marine Calcium Carbonates," Ph.D. Thesis, Washington University, St.
Louis, Mo. June 1963.
3. Edward, K.W., "Isotopic Analysis of Uranium in Natural Waters by Alpha
Spectroscopy," Geological Survey Water Supply Paper 1696-F, (1968).
4. Grimaldi, F.S., et al., "Collected Papers on Methods of Analysis for
Uranium and Thorium," Geological Survey Bulletin 1006, (1954).
109
-------
APPENDIX A
METHOD CAPABILITIES
PRECISION AND ACCURACY SUMMARY
Method
#
900.0
900.0
900.1
901.0
902.0
903.0
903.1
904.0
905.0
906.0
907.0
pCi/1
Drinking Type Minimum
Water of Detectable %
Procedure Testing! Level2 Precision
(3-Sigma)
Gross Alpha
Gross Beta
Gross Radium
Screen
Cesium
Iodine
Alpha Emitting
Radium Isotopes
Radium-226
Radium-228
Strontium
Tritium
Actinides
(Tentative)
C 1.0
C 0.5
R 0.25
R . 1.0
C 1.0
C 0.5
C 0.5
R 1.0
C 1.0
R 0.5
C 0.5
C 300
U
no
15
8
10
4
2,
5
15
15
30
5
15
25
_
• %
Coefficient
Variation %
Bias
±12 ±10
•± 5 ±5
± 5 ±10
± 5 ±15
± 4 ±10
±25 ±30
±10 ±20
: ±30 ±5
±20 ± 5
±5 ±5
, ±20 ± 5
±5 ±5
_
-------
Drinking Type
Method Water of
# Procedure . Testing!
pCi/1,
Minimum
Detectable %
Level2 Precision
(3-$igma)
Coefficient
Variation %
Bias
908.0 Uranium- R
Radiochemical
908.1 Uranium- R
Fluorometry
1.0
1.0
±10
±15
± 8
± 5
0) C = results of collaborative test study
R - results of single-lab replicate test study
U = results are forthcoming
Based on 1000 ml sample and 100 min counting time unless otherwise
designated in the procedure.
Ill
-------
APPENDIX B
ERROR AND STATISTICAL CALCULATIONS
Radioactivity determinations include analytical and counting errors. In the
collaborative testing for each method, estimated standard deviations were
reported which included both analytical and counting errors. The total
error can only be determined when a large number of samples are analyzed.
In order to have an estimate of the variation in a single analysis, a
counting error is calculated. For an analysis of a single sample, this
calculation will ensure that the counting error contribution to the total
error is relatively small.
Because of the random nature of radioactive disintegrations there is an
error associated with any measured count of these disintegrations. The
variability of any measurement is indicated by the standard deviation. The
standard deviation Sn, of the net counting rate, is determined by the
following equation:
1/2
(1)
where:
R0 =
t! -
B =
t2 =
gross count rate
counting time for the gross count
background count rate
counting time for the background count
The counting error (CE) for a given sample expressed in pCi/1 and at
the 95% confidence level is shown by:
CE-
1.96 Sn x 1000
2.22 E VF
(2)
where:
1.96 = 95% confidence factor
2.22 = conversion factor from dpm/pCi,
112
-------
E = efficiency factor, cpm/dpm
V - volume of the aliquot analyzed, in ml
F = recovery factor
The best estimate of standard deviation of a number of experimental analyses
or observations, (S0)> is determined by:
- x)2/(n -
1/2
(3)
where:
x-j
x
n
activity (pCi/ml) of a given sample
mean activity (pCi/ml) of a series of analyses
the number replicate analyses
113
-------
APPENDIX C
DETERMINATION OF COUNTING TIME
FOR REQUIRED SENSITIVITY
This is the information and equations to be used for the determination of
required counting times to meet the required sensitivities (detection
limits) as given in the National Interim Primary Drinking Water Regulations
(NIPDWR) (July 9, 1976) Section 141.25(c), and to be used in the monitoring
for radionuclfdes under the Nuclear Regulatory Commission (NRC) and the
Department of Energy (DOE) programs.
Three methods of calculation are provided: The first method is based on the
definition of sensitivity in terms of detection limit in the NIPDWR. The
second method is based on the lower limit of detection "LLD" as given in
HASL-300, part D-08, and is recommended by the NRC and DOE. The second
method includes a preselected percent chance of a false positive result for
a sample having no activity (a) as well as a preselected per cent of confi-
dence of detecting activity (1-3). In the NIPDWR the 1-3 is given as 0.95
or 95% confidence. An a = 0.05 and 1-3 = 0.95 have been selected for the
second method below. The third method is similar to the second method but
based on approximations to the first method.
Method I
From the definition of sensitivity (detection limit) in the NIPDWR, at a
precision of ± 100% at the 95% confidence level, the net count rate (N)
would be:
N
1.96
(1)
Also, the standard deviation, (Sn) of the net count rate, (N), can be
calculated from Equation 1 (Appendix B).
R
B
1/2
(2)
where:
R0 = gross count rate = net count rate (N) plus the background
count rate (B)
t] and t2 = the counting times for the gross count and back-
ground count respectively.
114
-------
Equating equations (1) and (2):
N = 1.96
R0 + B
1/2
(3)
This can be further simplified by setting R0 = N + B.
When sample radioactivity count rate is near the detector background count
rate (as with drinking water and other environmental type samples), then the
sample counting time and the detector background counting time should be
about equal.
If the sample counting time (t-]) is equal to the background counting time
(t2), and R0 = N + B, then equation (3) can be simplified to:
Solving for t,:
N = 1.96
N + 2B
'1
1/2
t, = 3.84 N + 7.68B
I /i
(4)
(5)
Example 1
Assume a water supply has a total dissolved solids, (TDS) of 80 mg/250 ml
(320 mg/1), the counting system has a counting efficiency of 6.00% (0.0600
cpm/dpm) for 24'Am alpha particles emitted from a 2-inch diameter dish
containing 80 mg of water solids, and an alpha background of 0.05 cpm. How.
long must a 80 mg/250 ml aliquot (evaporated) be counted to meet the
required 3 pCi/1 sensitivity?
For the assumptions given the net counting rate (N) would be:
N = Sensitivity x volume x efficiency x 2.22
N = (3 pCi/1) (0.25 1) (0.06 cpm/dpm) (2.22 dpm/pCi)
N = 0.0999 cpm
Then substituting N = 0.0999 and B = 0.05 into equation (5) gives a required
counting time of:
t] = 3.84 (0.0999) + 7.68 (0.05) = 77 min.
(0.0999)2
Example 2
Assume a water supply has a TDS of 80 mg/100 ml (800 mg/1) and the same
counting efficiency and alpha background as above. What counting time will be
115
-------
required for the 3 pCi/1 sensitivity?
For the assumptions given the net counting rate (N) would be:
N = (3 pCi/1) (0.1 1) (0.060 cpm/dpm) (2.22 dpm/pCi)
N s 0.040 cpm
Then substituting N s 0.040 and B = 0.05 into equation (5) gives a required
counting time of:
'1
3.84 (0.040) +7.68 (0.05) B 336
(0.040)2
Method II
From HASL-300* the LLD may be approximated as LLD 2? (K« + Kg)S0
where:
(1)
Ka = the value for the percentile of the standardized normal
variate corresponding to the preselected risk for concluding
falsely that activity is present (a),
KB s the corresponding value for the predetermined degree of
confidence for detecting the presence of activity (1-6), and
S0 s the estimated standard error for the net sample activity
If the values of a and e are set at the same level and if the gross activity
and background activity are close, the following approximation may be made:
(S2gross -f S* )1/2= (2 S2h)1/2 = Sh .(2)
1/2
bkg
SQ
Then, equation (1) becomes
LLD
= 1.414
(2)
= 2K SQ * 2K (1.414Sb)
LLD = 2.828K $
(3)
The values for K for common ct's are:
„ 1 R
Ct IP
2.828K
0.01
0.02
0.05-
0.10
0.16
0.50
0.99
0.98
0.95
0.90
0.84
0.50
2.377
2.054
1.645
1.282
1.000
0
6.59
5.81
4.66
3.63
2.83
0
Harley, 0. H., ed. EML Procedures Manual» HASL-300, Env. Meas. Lab.,
U.S.DOE, New York, NY (1972)
116
-------
In the equation LLD = 2.83KSb, $5 = (Bkg count) V2 and the Bkg
count = Bkg count rate x counting time (Bt)
Sb = (Bt)V2
LLD = 2.828K-Sb = 2.828 K-(Bt)V2
N = LLD = Sample net count rate
Set N = LLD = 2.828K -(Bt)
t
1/2
and solve for t:
Nt = 2.828K (Bt)V2
t (N2t - (2.828)2|<2B) = 0.
Use the positive root for t:
t = (2.828)2K2B
(4)
(5)
(6)
(7)
(8)
(9)
For a = 0.05 and 1-g = 0.95, K =1.645, using equation (9), we get:
t = (4.66)2 B = 21.71 B
'"""? ~f~
then using the data for the same examples for Method I, the
following results are obtained for Method II:
Example 1
Alpha background (B) = 0.05 cpm
Sample net count rate should be (N) = 0.0999 cpm for a required
sensitivity or detection limit of 3 pCi/1.
then: t = 21.71 (0.05) = 1.09 = 109 min.
(0.0999)'
0.01
Example 2
Alpha background (B) = 0.05 cpm
Sample net count rate should be (N) =
0.040 cpm
117
-------
then:
t =
21.71 (0.05)
(0.040)2
1.09 = 678 min.
0.0016
Method III
The definition of LLD from HASL-300 uses the approximation that the sample
counting time and the background counting time are the same. A second
approximation considers that the net count is very small or very close to
zero. If these two approximations are also used with the EPA definition, we
then would have:
LLD = N = 1.96 Iff = 1.96->/2~ fl~ = 2.77 Sb
LLD = N = 2.77 Sb
This definition is the approximation of the EPA definition converted to the
HASL-300 form (equation 5)
LLD = 2.828K • Sb
If we set 2.77 Sb = 2.828K Sb :
Then K = 0.98
This gives LLD = 2.828 • 0.98 Sb = 2.77 Sb
for K = 0.98, this is equivalent to an a, of 16% and 1-g of 84%.
Therefore, the table shows 2.77 Sb values for time, since this is the
HASL-300 approximation of the EPA definition.
The table gives values of t for:
_ (2.828)2 (0.98)2 B
t =
7.681B
N2
Example 1
Alpha background (B) = 0.05 cpm
Sample net count rate should be (N) = 0.0999 cpm for a required
sensitivity or detection limit of 3 pCi/1.
then
Example 2
4- _
7.681 (0.05)
(0.0999)2
0.384
0.01
= 38.4 min.
Alpha background (B) = 0.05 cpm
Sample net count rate should be (N) = 0.040 cpm
then
7.681 (0.05)
(0.040)2
0.384
0.0016
= 240 min.
118
-------
The next several tables contain compilations of required counting
times for several conditions in order to attain a specified
sensitivity. These tables only indicate the required counting times
for an arbitrary set of conditions. In a laboratory, for a real set
of conditions, when the required counting time becomes excessive
(>1000 min), it is recommended that a new counting system or a larger
sample or a combination of both, be used.
119
-------
REQUIRED COUNTING TIMES FOR SENSITIVITY OF
1 PCI/LITER
BKGD
C P M
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
BKGD
C P M
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
BKGD
C P M
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
BKGD
G P M
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
REQ NET
C P M
0.04
0.18
0.36
0.07
0.36
0.71
0.11
0.53
1.07
REQ NET
C P M
0.04
0.18
0.36
0.07
0.36
0.71
0.11
0.53
1.07
REQ NET
C P M
0.04
0.18
0.36
0.07
0.36
0.71.
0.11
0.53
1.07
REQ NET
C P M
0.04
0.18
0.36
0.07
0.36
0.71
0.11
0.53
1.07
EPA
T, MIN
412.6
33.8
13.9
130.2
13.9
6.2
69.9
8.6
3.9
EPA
T, MIN
717.1
46.0
16.9
206.3
16.9
6.9
103.7
9,9
4.3
EPA
T, MIN
6197.9
265.2
71.7
1576.5
71.7
20.6
712.7
34.3
10.4
EPA
T, MIN
61005.3
2457.5
619.8
15278.4
619.8
157.7
6802.4
277.9
71.3
4.66 S
T, MIN
860.6
34.4
8.6
215.1
8. 6
: 2.2
95.6
3.8
i 1«°
4.66 S
T, MIN
1721.2
68 . 8
17.2
430. 3
17.2
4.3
191.2
7.6
1.9
4.66 S
T, MIN
17211.8
688.5
172.1
4303.0
172.1
43.0
1912.4
76.5
19.1
4.66 S
T, MIN
172118.1
6884.7
1721.2
43029.5
1721.2
430.3
19124.2
765.0
191.2
120
-------
REQUIRED COUNTING TIMES FOR SENSITIVITY OF
2 PCI/LITER ;-
BKGD
C P M
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
BKGD
C P M
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
BKGD
C P M
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
BKGD
C P M
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
REQ NET
C P M
0.07
0.36
0.71
0.14
0.71
1.42
0.21
1.07
2.13
REQ NET
C P M
0.07
0.36
0.71
0.14
0.71
1.42
0.21
1.07
2.13
REQ NET
C P M
0.07
0.36
0.71
0.14
0.71
1.42
0.21
1.07
2.13
REQ NET
C P M
0.07
0.36
0.71
0.14
0.71
1.42
0.21
1.07
2.13
EPA
T, MIN
130.S2
13.9
6.2
46.1
6.2
2.9
26.5
3.9
1.9
EPA
. T, MIN
• ""
206.3
16.9
6.9
65.1
6.9
3.1
34.9
4.3
2.0
EPA
T, MIN
1576.5
71.7
20.6
407.6
20.6
6.5
187.2
10.4
3.5
EPA
T, MIN
15278.4
619.8
157.7
3833.1
157.7
40.8
1709.6
71.3
18.7
4.66 S
T, MIN
215.1
8.6
2.2
53.8
2.2
0.5
23.9
1.0
0.2
4.66 S
T, MIN
430.3
17.2
4.3
107.6
4.3
1.1
47.8
1.9
0.5
4.66 S
T, MIN
4303.0
172.1
43.0
1075.7
43.0
10.8
478.1
19.1
4.8
4.66 S
T, MIN
43029.5
1721.2
430.3
10757.4
430.3
107.6
4781.1
191.2
47.8
121
-------
REQUIRED COUNTING TIMES FOR SENSITIVITY OF
3 PCI/LITER
BKGD
C P M
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
BKGD
C P M
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
BKGD
C P M
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
BKGD
C P M
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
COUNTNG
EFF, %
16 '
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48 "
48
48
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
. 1000
SAMPLE
SIZE; ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100-
500
1000
100
500
1000
100
500
1000
REQ NET
C P M
0.11
0.53
1.07
0.21
1.07
2.13
0.32
1.60
3.20
REQ NET
C P M
o.ii
0.53
1.07
0.21
1.07
2.13
0.32
1.60
3.20
REQ NET
C P M
0.11
0.53
1.07
0.21
1.07
2.13
0.32
1.60
3.20
REQ NET
C P M
0.11
0.53
1.07
0.21
1.07
2.13
0.32
1.60
3.20
EPA
T, MIN
69.9
8.6
3.9
26.5
3.9
1.9
15.8
2.6
1.2
EPA
T, MIN
103.7
9.9
4.3
34.9
4.3
2.0
19.5
2.7
1.3
EPA
T, MIN
712.7
34.3
10.4
187.2
10.4
3.5
87.2
5.4
2.0
EPA
T, MIN
6802.4
277.9
71.3
1709.6
71.3
18.7
763.8
32.5
8.7
4.66 IS
T, .MIN
95.6
3.8
1.0
23.9
' 1.0
0.2
10.6
0.4
1 O.I
4.66 8
T, MIN
191.2
7.6
1.9
47.8
1.9
0.5
;21.2
: 0.8
0.2
4.66 !3
T,' MIN
1912.4
76.5
19.1
478. 1
•19.1
4.8
212, 5
8.5
. 2.1.
4.66 £3
T, MIN
19124.2
765.0
191.2
4781.1
191.2
47.8
. 21-24.9
85.0
•21.2
122
-------
REQUIRED COUNTING TIMES FOR SENSITIVITY OF
4 PCI/LITER
BKGD
C P M
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
BKGD
C P M
0.10
0.10
0.10
,0.10
0.10
0.10
0.10
0.10
0.10
BKGD
C P M
1.00
1.00
1.00
1.00
1.00
1.00
i.oq
1.00
1.00
BKGD
C P M
10.00
10.0Q
10.00
10.00
10.00
10.00
10.00
10.00
io.oo
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
SAMPLE"
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
100Q
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
ioo
500
1000
100
500
1000
100
50Q
1000
REQ NET
C P M
0.14
0.71
1.42
0.28
1.42
2.84
0.43
2.13
4.26
REQ NET
C P M
0.14
0.71
1.42
0.28
1.42
2.84
0,43
2.13
4.26
REQ NET.
C P M
0.14
0.71
1.42
0.28
1.42
2.84
0.43
2.13
4.26
REQ NET
C P M
0.14
0. 71
1.42
0.28
1.42
2.84
0.43
2.13
4.26
EPA
T, MIN
46.1
6.2
2.9
18.3
2.9
1.4
11.1
1.9
0.9
EPA
T, MIN
65.1
6.9
3.1
23.0
3.1
1.4
13.2
2.0
0.9
EPA
T, MIN
407.6
20.6
6.5
108.7
6.5
2.3
51.3
3.5
1.3
EPA
T, MIN
3833. 1
157.7
40.8
965.0
40.8
10.9
431.9
18.7
5.1
4.66 S
T, MIN
53.8
2.2
0.5
13.4
0.5
0.1
6.0
0.2
0.1
4.66 S
T, MIN
107.6
4.3
1.1
26.9
1.1
0.3
12.0
0.5
0.1
4.66 S
T, MIN
1075.7
43.0
io;s
268.9
10.8
2.7
119.5
4.8
1.2
4.66 S
T, MIN
10757.4
430. 3
107.6
2689.3
107.6
26.9
1195.3
47.8
12.0
123
-------
REQUIRED COUNTING TIMES FOR SENSITIVITY OF
10 PCI/LITER
BKGD
C P M
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
0.05
BKGD
C P M
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
0.10
BKGD
C P M
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
BKGD
C P M
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
10.00
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
COUNTNG
EFF, %
16
16
16
32
32
32
48
48
48
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
SAMPLE
SIZE, ML
100
500
1000
100
500
1000
100
500
1000
REQ NET
C P M
0.36
1.78
3.55
0.71
3.55
7.10
1.07
5.33
10.66
REQ NET
C P M
0.36
1.78
3.55
0.71
3.55
7.10
1.07
5.33
10.66
REQ NET
C P M
0.36
1.78
3.55
0.71
3.55
7.10
1.07
5.33
10.66
REQ NET
C P M
0.36
1.78
3.55
0.71
3.55
7.10
1.07
5.33
10.66
124
EPA
T, MIN
13.9
2.3
1.1
6.2
1.1
0.5
3.9
0.7
0.4
EPA
T, MIN
16.9
2.4
1.1
6.9
1.1
0.6
4.3
0.7
0.4
EPA
T, MIN
71.7
4.6
1.7
20.6
1.7
0.7
10.4
1.0
0.4
EPA
T, MIN
619.8
26.5
7.2
157.7
7.2
2.1
71.3
3.4
i.o
4.66 S
T, MIN
8.6
0.3
0.1
2.2
0.1
0.0
1.0
0.0
i 0.0
4.66 S
T, MIN
17.2
0.7
0.2
4.3
0.2
0.0'
1.9
0.1
0.0
4.66 S
T, MIN
172.1
6.9
1.7
43.0
1.7
0.4
19.1
0.8
0.2
4.66 S
T, MIN
1721.2
68.8
17.2
430.3
17.2
4.3
191.2
7.6
1.9
-------
APPENDIX D
. LABORATORY APPARATUS SPECIFICATIONS
Gas-flow proportional counting system: A gas-flow proportional counting
system may be used for the measurement of gross alpha and gross beta
activities. The detector may be either a "windowless" (internal propor-
tional counter) or a "thin window" type. A minimum shielding equivalent
to 5 cm of lead should surround the detector. A cosmic (guard) detector
operated in anticoincidence with the main sample detector will convert
this system to a low-background beta counter (< 3 cpm). The system
shall be such that the sensitivity of the radioanalysis of water samples
will meet or exceed the requirements of the drinking water promulgated
standards. The instrument should have a lengthy voltage plateau for
detecting alpha or beta radioactivity plus a sealer consisting of a
register, power supply, amd amplifier.
Scintillator detector system: For measurement of alpha activities a
scintillation system designed for alpha counting may be substituted for
the gas-flow proportional counter described. In such a system, a Mylar
disc coated with a phosphor (silver-activated zinc sulfide) is placed
directly on the sample or on the face of a photomultiplier tube,
enclosed within a light-tight container, along with the appropriate
electronics (high voltage supply, amplifier, timer, and sealer).
Gamma spectrometer systems: Either a sodium iodide (Nal(Tl)) crystal or
a solid state lithium drifted germanium (Ge(Li)) detector used in con-
junction with a multichannel analyzer is required if the laboratory is
to be certified for analyses of photon emitters from man-made radio-
nuclides.
If a sodium iodide detector is used, a 10 cm X 10 cm Nal cylindrical
crystal is recommended, although, a 7.5 cm X 7.5 cm crystal is satisfac-
tory. The detector must be shielded with a minimum of 10 cm of iron or
equivalent. It is recommended that the distance from the center of the
detector to any part of the shield should not be less than 30 cm. The
multichannel analyzer, in addition to appropriate electronics, should
contain a memory of not less than 200 channels.
A system with a lithium drifted germanium (Ge(Li) detector may be used
for measurement of these photon emitters if the efficiency of the
detector is suc,h that the sensitivity of the system meets the minimum
detectable activity requirements.
125
-------
4.
Beta/Gamma coincidence scintillation system. Since iodine-131 has a
distinctive beta-gamma decay chain and a high enough beta-particle
energy to be efficiently detected, a beta/gamma coincidence technique
can be employed for quantification. A system of high-resolution
detectors and multichannel analyzers results in very low background.
Liquid scintillation spectrometer counting system. The measurement of
low-energy beta emitters such as tritium or carbon-14 can be best
determined by liquid scintillation counting. These instruments use an
organic phosphor as the primary detector. This organic phosphor is
combined with the sample in an appropriate solvent that achieves a
uniform dispersion. The counting system normally uses two multiplier
phototubes in coincidence, thus providing a lower background. In order
to minimize detectable radioactivity, scintillation-grade organic
phosphors and solvents, and low-potassium scintillation vials are used.
Scintillation cell system: For the specific measurement of radium-226 by
the radon emanation method, a scintillation system designed to accept
scintillation flasks ("Lucas cells") shall be used. The system consists
of a light-tight enclosure capable of accepting the scintillation
flasks, a detector (phototube), and the appropriate electronics (high
voltage supply amplifier timers and sealers). The flasks (cells)
required for this measurement may either be purchased from commercial
suppliers or constructed according to published specifications.
Radon emanation apparatus:
consists of:
This specialized glassware apparatus
Radon bubbler - Figure 2.
Scintillation cell - Figure 3.
The glassware can be fabricated by a competent glassblower, and the
scintillation cell can be purchased from specified companies.
8. Fluorometer: An instrument to measure the fluorescence of a fused disc
of a uranium compound exposed to ultraviolet light. The response to
this excitation is proportional to the concentration of uranium in the
drinking water sample. One of the specifications of the fluorometer is
that it should be able to measure 0.0005 jag of uranium or less.
9. Analytical balance: Minimum scale readability, 0.1 mg.
10. Centrifuge:
10.1 General purpose table-top model with a maximum speed of at least
3,000 rpm and a loading option of 4 x 50 ml.
10.2 Floor model with a maximum speed of 2,000 rpm and a loading option
of 4 x 250 ml centrifuge bottles.
11. pH meter: Accuracy, ±0.5 units. Scale readability, ±0.1 units.
Instrument may be either line/bench or battery/portable.
126
-------
12. Electric hot plate: This instrument should have a built-in stirrer, and
st.epless temperature controlsvwhich can-be changed as heating
requirements may demand.
13. Drying oven: The gravity convection type is recommended, having
thermostatic controls to maintain desired temperature.
14. Mylar film: As a covering for precipitates to protect them during
counting and storage, the thickness suggested is 0.0005 inches, in rolls
of 1-1/2 inch width.
15. Stainless steel counting planchets: These should be fabricated from
uniform surface density stainless steel and capable of withstanding
nitric acid and heat treatment. The planchets should be flat, have a
raised wall to contain the sample being evaporated and should be of the
size determined by the inside diameter of the detector.
16. Drying lamps: As a minimum, these should consist of 250 watt infrared
lamps with built-in reflectors that can be mounted on porcelain support
stands.
17. Teflon filter holder: A"fabricated device for filtering precipitates
prior to mounting. These teflon units are to be made in dimensions
compatible with the size of the plastic ring and disc mounts.
18. Plastic ring and disc mounts: These are plastic units molded of nylon
in dimensions compatible with the size of the counting chamber of the
counting instrument.
19. Desiccator:
Aluminum models, normally used for plastic ring and disc planchets.
Glass models, capable of holding a vacuum, and large enough to hold
dried S.S. planchets until ready for counting.
20. Glassware: Borosilicate type glass. All glassware should meet Federal
specifications. Beakers, 250 ml larger are required for specific
analyses.
21. Glass fiber filters: These are type A-E, 47 mm in diameter.
22. Membrane filters: Metricel, 47 mm GA-6, 0.45 \i size.
23. Alpha sensitive phosphors - alpha phosphor disc, 24 mm ASP-4.
127
-------
APPENDIX E
REPRESENTATIVE SOURCES OF LABORATORY SUPPLIES
Counting planchets
"a) Stainless steel
Coy Laboratory Products
P. 0. Box 1108
Ann Arbor, Mich. 48106
(313) 663-1320
Specifications: Catalog #75750 2 x 0.018 x 0.25 inches
b) Plastic ring and disc mounts Control Molding Corp.
84 Granite Avenue
Staten Island, N. Y. 10303
(212) 442-8733
Specifications: Catalog #«J-356, 1" dia (natural) nylon type 6/6
Glass-fiber filter paper Reeve-Angel
Whatman, Inc.
9 Bridewell Place
Clifton, N.J. 07014
(201) 777-4825
(201) 773-5800
Specifications: Grade 934AH, 2.8 cm
Electrodeposition apparatus Sargent-Welch Scientific Co.
10400 Taconic Terrace
Cincinnati, Ohio 45215
(513) 771-3850
Specifications: Catalog #5-29465, Sargent-Slomin model
Membrane filters
Metricel, GA-6, 0.45u 25 mm and 47 mm
Gelman Instrument Company
600 S. Wagner Road
Ann Arbor, Mich. 48106
(313) 665-0651
Catalog #60173
Fisher Scientific
585 Alpha Drive
Pittsburg, Pa. 15238
(412 781-3400
Catalog #9-730-20
Mylar film
Retail quantities can be obtained from local distributors:
Specifications: 0.0005" (0.5mil) thick. Manufactured only
by E.I. DuPont de Nemours.
128
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6. Phosphors, alpha sensitive
Specifications:
W. B. Johnson & Associates,
Research Park
Montville, N. J. 07045
(201) 334-9222
Catalog #ASP-4, 24 mm disc
Inc.
7.._ Polypropylene centrifuge tube Nalgene Labware
Retail quantities available from local distributors
Specifications: 134 mm x 28.7 mm O.D., Nalge #3100
50 ml Tube closure 29C, Nalge #04085
8. Radon emanation bubblers
These and associated glassware can be fabricated by local glass
companies with the specifications from Figures 3 and 4.
9. Scintillation solutions (commercial)
Packard Instruments Company
2200 Warrenvilie Road
Downers Grove, 111. 60515
(312) 969-6000
Instagel
Isolab, Inc.
Drawer 4350
Akron, Ohio 44321
(216) 825-4528
Scintisol Complete
Fisher Scientific Co.
717 Forbes Road
Pittsburgh, Pa. 15219
(412) 562-8300
Scintiverse "Scintidiox"
Beckman Instruments Inc.
2500 Harbor Blvd.
Fullerton, Calif. 92634
(714) 871-4848
Ready-Solv MP
New England Nuclear
549 Albany Street
Boston, Mass. 02118
(617) 482-9595
Aquasol
Mallinckrodt, Inc.
Science Products Division
P. 0. Box 5439
St. Louis, Mo. 63147
(314) 895-0123
Handifluor
J. T. Baker Chemical Co.
222 Red School Lane
Phillipsburg, N. «J. 08865
(201) 859-2151
"Scintrex"
10. Scintillation vials
Specifications:
Catalog #6001075
Polyethylene or low potassium glass
20 ml capacity 22 mm screw cap
Packard Instrument Company
2200 Warrenville Rd.
Downers Grove, 111. 60515
(312) 969-6000
129
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Catalog NEF #938
Catalog #966350
11. Teflon filter holder
New England Nuclear
549 Albany Street
Boston, Mass. 02118
(617) 482-9595
Beckman Instrument Company
Campus Drive at Jamboree Blvd.
P. 0. Box C-19600
Irvine, Calif. 92713
(714) 833-0751
Atomic Products Corporation
Center Moriches, N. Y. 11934
(516) 878-1074
Fluorulon Laboratories
Box 305
Caldwell, N. J. 07006
130
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APPENDIX F
REPRESENTATIVE SOURCES OF LABORATORY COUNTING INSTRUMENTS
Gas Flow Proportional Counting Systems: The range of prices for a
complete system is from $3000 - $10,000.
1. Canberra Industries
45 Gracey Avenue
Meriden, Conn. 06450
(203) 238-2351
2. Nuclear Measurements Co.
24 N. Arlington Avenue
Indianapolis, Ind. 46218
(317) 546-2415
3. Tracer Analytic
1842 Brummel Drive
Elk Grove Village, 111. 60007
(312) 364-9100
6.
Beckman Instruments, Inc.
2500 Harbor Boulevard
Fullerton, Calif. 92634
(714) 871-4848
LND, Inc.
3230 Lawson Boulevard
Oceanside, N. Y. 11572
(516) OR-8-6141
Baird-Atomic, Inc.
125 Middlesex Turnpike
Bedford, Mass. 01730
(617) 276-6000
II. Liquid Scintillation Spectrometer Counting Systems: Depending upon
what accessories are wanted, the price will range from $15,000 -
$30,000.
1.
2.
3.
Packard Instrument Co.
2200 Warrenville Road
Downers Grove, 111. 60616
(312) 969-6000
Beckman Instruments, Inc.
2500 Harbor Boulevard
Fullerton, Calif. 92634
(714) 871-4848
Tracor Analytic
1842 Brummel Drive
Elk Grove Village,
(312) 364-9100
111. 60007
131
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Ill,
IV.
Scintillation Cell (Radon-Emanation) Counting Systems: At the
present time one complete unit will be about $2500.
Specifications:
Bias network, detector circuits, 6 digit
decade counter. External high voltage
supply and 2-inch photomultiplier tubes.
2.
Randam Electronics, Inc. 4.
3091 Shadycrest Drive
Cincinnati, Ohio 45239
(513) 522-3322
Johnson Laboratories,Inc. 5.
Three Industry Lane
Cockeysville, Md. 21030
(301) 666-9500
Eberline Instrument Corp.
Airport Road, P.O. Box 2108
Santa Fe, N. M. 87501
(505) 471-3232
Ludlum Measurements Corp., Inc.
501 Oak Street
Sweetwater, Texas 79556
(915) 235-5494
Ortec, Inc.
100 Midland Road
Oak Ridge, Tenn.
(615) 482-4411
37830
Gamma Spectrometer Counting Systems: From the simplest system to
one completely automated and including computer capabilities, the
prices will range from $6,000 - $50,000.
1. Canberra Industries 5.
45 Gracey Avenue
Meriden, Conn. 06450
(203) 238-2351
2. Packard Instrument Co. 6.
2000 Warrenvilie Rd.
Downers Grove, 111. 60515
(312) 969-6000
3. Edax International, Inc. 7.
P. 0. Box 135
Prairie View, 111. 60069
(312) 634-3870
Ortec, Inc.
100 Midland Road
Oak Ridge, Tenn. 37830
(615) 482-4411
8.
Nuclear Data, Inc.
Golf and Meacham Road
Schaumberg, 111. 60172
(312) 884-3600
Nuclear Enterprises, Ltd.
935 Terminal Way
San Carlos, Calif. 94070
(415) 593-1455
Bicron Corp.
12345 Kinsman Rd.
Newbury, Ohio 44065
(216) 564-2251
Tracer Northern, Inc.
2551 W. Beltline Hwy.
Middleton, Wise. 53562
(608) 836-6511
132
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/4-8Q-032
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
"Prescribed Procedures for Measurementiof Radioactivity
in Drinking Water"
5. REPORT DATE
August 1980
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO
Herman L. Krieger and Earl L. Whittaker
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
Radiological Methods Section
Physical and Chemical Methods Branch
Environmental Monitoring and Support Laboratory
Cincinnati, Ohio 45268
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Environmental Monitoring and Support Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
In-house
14. SPONSORING AGENCY CODE
EPA/600/06
15. SUPPLEMENTARY NOTES
This report is an update of the "Interim Manual," EPA-600/4-75-008, March 1976
16. ABSTRACT
Appropriate radiochemical procedures have been compiled in a laboratory manual
131 US??fi/??R6 ansqyqnS of.9ross a1Pha activity, gross beta activity, 134/137Cs,
•n, ' Ji * Ra' Sr' H' Uran1um» and the actinide elements, in drinking water.
These .methods possess the necessary sensitivity for achieving the maximum contaminant
levels recommended by the U.S. Environmental Protection Agency in its Interim Primary
Drinking Water Regulations. The method capabilities and minimum detection levels
,nH6. i6ierYdet?rmin?d ^y replicate testing, by an internal quality assurance proqram
and collaborate test studies specifically designed for these nuclides. program'
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN. ENDED TERMS
c. COSATI Field/Group
^adiochemistry
ladioactive pollutants
Potable water
luality control
JRadiochemical analysis
Methodology
Maximum contaminant level
Minimum detection level
13B
8. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThisReport)'
Unclassified
21. NO. OF PAGES
143
20. SECURITY CLASS (Thispage)
Unclassified
22. PRICE
' EPA Form 2220-1 (9-73)
133
U.S. GOVEBNMENT PRINTING OFFICE: 1980-657-165/0060
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