EPA-600/4-75-008 (Revised)
March 1976
Environmental Monitoring Series
INTERIM RADIOCHEMICAL METHODOLOGY
FOR DRINKING WATER
Environmental Monitoring and Support Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati. Ohio 45268
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into five series. These five broad
categories were established to facilitate further development and application of
environmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL MONITORING series.
This series describes research conducted to develop new or improved methods
and instrumentation for the identification and quantification of environmental
pollutants at the lowest conceivably significant concentrations. It also includes
studies to determine the ambient concentrations of pollutants in the environment
and/or the variance of pollutants as a function of time or meteorological factors.
This document is available to the public through the NatiorH Technical Informa-
tion Service. Springfield, Virginia 22161.
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EPA-600/4-75-008(Revised)
March 1976
INTERIM RADIOCHEMICAL METHODOLOGY FOR DRINKING WATER
by
Herman L. Krieger
Radiochemistry § Nuclear Engineering Branch
Environmental Monitoring and Support Laboratory
Cincinnati, Ohio 45268
Program Element No. 2FH120/1HA327
Prepared for
Office of Radiation Programs
U.S. Environmental Protection Agency
Washington, D.C, 20460
U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Environmental Monitoring and
Support Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Mention of trade names or commercial products does not
constitute endorsement or recommendation for use.
11
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FOREWORD
Environmental measurements are required to determine the quality of
ambient waters and the character of waste effluents. The Environmental
Monitoring and Support Laboratory-Cincinnati conducts research to:
• Develop and evaluate techniques to measure the presence
and concentration of pollutants in water, wastewater,
bottom sediments, and solid waste.
• Investigate methods for the concentration, recovery, and
identification of viruses, bacteria, and other micro-
biological organisms in water. Conduct studies to de-
termine the responses of aquatic organisms to water
quality.
• Develop and maintain a quality assurance program to assure
standardization and quality control of systems used for
monitoring water and wastewater.
The Proposed Interim Drinking Water Regulations describe the
maximum contaminant levels for a variety of pollutants in drinking
water. This manual, which was compiled by the Radiochemistry and
Nuclear Engineering Branch, EMSL-Cincinnati, provides interim analyt-
ical methodology for the monitoring of radionuclides in drinking water.
In detail, it describes those radioanalytical procedures which meet the
needs of laboratories having responsibility for monitoring of municipal
water supplies. It is anticipated that the radioanalytical methods
described herein will either be superseded by, or established as, EPA
Reference Methods prior to the promulgation of the Final Primary Drinking
Water Regulations.
This effort has been supported by the Office of Radiation Programs,
U. S. Environmental Protection Agency, Washington, D. C.
Dwight G. Ballinger
Director
Environmental Monitoring and Support Laboratory
Cincinnati
111
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ABSTRACT
Interim radiochemical procedures have been compiled in a laboratory
manual for use in the analysis ,o£ gross alpha^activity, gross beta activity,
134/137Cs, 13IIf 226/228Raj 89/90Sr> 3H and ?0K in drinking water> ^ese
methods possess the necessary sensitivity for achieving the maximum con-
taminant levels recommended by the U. S. Environmental Protection Agency in
its Interim Primary Drinking Water Regulations. The method capabilities
and minimum detection levels have been determined by replicate testing.
This revised edition considers these procedures as "interim" until they
are either superseded by, or established as, EPA Reference Methods prior to
the promulgation of the Final Primary Drinking Water Regulations.
IV
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PREFACE
The U. S. Environmental Protection Agency (EPA), is publishing Proposed
Interim Primary Drinking Water Regulations for Radioactivity under the Safe
Drinking Water Act, PL 93-523, which propose maximum contaminant levels
limiting the concentrations of natural and man-made radioactivity in drinking
water supplies and set forth the proposed monitoring requirements.
Recognizing the need for a collection of analytical methods that can be
used for measuring each of these radionuclides in drinking water, the
Radiochemistry and Nuclear Engineering Branch of the Environmental Monitoring
and Support Laboratory, EPA, has sought to bring methods, from a variety of
sources, together in a single volume for the convenience of those analysts
and technicians having responsibility for the analysis of drinking water
supplies.
As will be evident from the Method Capabilities section of the manual,
Appendix A, the sensitivity of each of the procedures is more than adequate
for the proposed limiting concentrations. This compilation includes single-
operator-tested procedures that have the required sensitivity for drinking
water guidelines. They have been selected from a number of radiochemical
methodology collections,(1~5) and have been prepared so they can be utilized
for routine analysis. Several of them have already been published as
"standard reference methods" by recognized standard-setting organizations
such as ASTM and APHA. Factors considered in selecting these procedures for
inclusion in this laboratory manual were procedure time and method capabilities.
In those cases where modifications were deemed essential, additional steps
such as scavenging or other purification techniques have been included in the
procedures. (See Appendix A.)
Drinking water is normally collected at "grab" sampling points and
should not be acidified until the start of the analysis, if so indicated.
Radiochemical analysis should be performed immediately upon receipt of
sample, especially for •" I so that radioactive decay losses are minimized.
When quarterly composites are set aside for future analyses, the samples
should be acidified with 1 ml 16 N^ HN03 per liter to minimize losses caused
by adsorption on container wall. Preparation of reagents is described in
Appendix B, and sources of supply in Appendix C.
Revisions or additions to these methods are solicited.
References:
1. Krieger, H. L. and S. Gold. Procedures for Radiochemical Analysis of
Nuclear Reactor Aqueous Solutions. EPA-R4-73-014, National Environmental
Research Center, U. S. Environmental Protection Agency, Cincinnati, Ohio
(May 1973).
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2. 1972 Book of ASTM Standards, Part 23. American Society for Testing
and Materials, Philadelphia, Pa. (1972).
3. Harley, J. H. Manual of Standard Procedures. USAEC Rept. HASL-300
(1972).
4. Nuclear Science Series, USAEC Rept. NAS-NS-3001 to NAS-NS-3111 (1965).
5. Standard Methods for the Examination of Water and Waste Water, 13th ed.
American Public Health Association, Washington, D. C. (1971).
VI
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CONTENTS
Page
Foreword ................................
Abstract ................................ iv
Preface ................................ v
Figures ................................ viii
Acknowledgment ............................. ix
Gross Alpha and Beta Radioactivity in Drinking Water .......... 1
Radioactive Cesium in Drinking Water .................. 4
Radioactive Iodine in Drinking Water
Precipitation Method ....................... 6
Distillation Method ........................ 9
Radium- 226 in Drinking Water
Alpha-Emitting Radium Isotopes - Precipitation Method ....... 13
Radon Emanation Technique ..................... 16
Radium- 2 28 in Drinking Water
Sequential Method Radium-228/Radium-226 .............. 24
Alpha-Emitting Radium Isotopes by Precipitation .......... 26
Radium-226 by Radon Emanation ................... 27
Radioactive Strontium in Drinking Water ................ 29
Tritium in Drinking Water ....................... 34
Potassium-40 in Drinking Water ..................... 38
Appendices
A. Method Capabilities ...................... 41
B. Reagent Preparation ...................... 42
C. Sources of Supply ....................... 47
VII
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FIGURES
Page
1. Generalized Gross Alpha and Gross Beta Self-Absorption Curves ... 2
2. Distillation Apparatus for Iodine Analysis 11
3. Radon Emanation Apparatus with Scintillation Cell 17
4. A Typical Radon Bubbler 18
5. The Growth of Radon-222 from Radium-226 20
6. A Typical Scintillation Cell for Radon Counting 21
7. Distillation Apparatus for Tritium Analysis 35
Vlll
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ACKNOWLEDGMENT
The Radiochemistry £ Nuclear Engineering Branch (R£NEB) of the Environ-
mental Monitoring and Support Laboratory, EPA, was requested to prepare
this manual by the end of fiscal year 75. It is one task milestone in the
Research Objective Achievement Plan of the Office of Research and Develop-
ment, and is intended for interim use by agencies responsible for monitoring
drinking water for radioactive contamination. George W. Frishkorn, Mrs. Betty
Jacobs, and Mrs. Eleanor Martin, R§NEB, were responsible for the thorough
testing of these procedures and for recommending modifications so that they
satisfy the limiting concentrations of the standard. Editorial comments
and suggestions for improvement in the clarity of the manual were submitted
by Dr. Bernd Kahn, Environmental Resources Center, Georgia Institute of
Technology, Atlanta, Georgia and Mr. Robert Lieberman, Eastern Environmental
Radiation Laboratory, Montgomery, Alabama..
Their assistance is gratefully acknowledged.
IX
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GROSS ALPHA AND BETA RADIOACTIVITY IN DRINKING WATER
Principle of Method
A drinking water sample is evaporated to a small volume, transferred
to a counting dish, and counted for gross alpha or gross beta activity.
Procedure Time
Evaporation time, 1 to 2 hours for eight 250-ml samples.
Reagents and Supplies
Planchets, stainless steel.
Procedure
1. Transfer 100 to 500 ml drinking water sample (Note 1) to a beaker and evap-
orate to a small volume on a hot plate.
2. Slurry residue to a tared stainless-steel planchet using a rubber police-
man and as little water as possible.
3. Dry under infra-red lamps, cool, weigh, and store in desiccator.
4. Alpha and beta count (Note 2).
Calculation
Calculate the concentration, D, of the gross activity (alpha and/or beta)
in picocuries per liter as follows:
D =
2.22 x EVW
where:
C = net count rate, counts/minute,
E = counter efficiency, alpha or beta (Note 3),
V = milliliters of sample used,
W = self-absorption factor (determined from solids concentration), and
2.22 = conversion factor from disintegrations/minute to picocuries.
Notes:
1. The specified volume of drinking water to be evaporated will be a function
of its hardness and solids concentration. Self-absorption factors for
the solids .present in these volumes have to be determined to correct for
losses due to self-absorption. In any event, the maximum sample thick-
ness should be less than 5 mg/cm2. (See Fig. 1.)
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Sample Thickness, mg/cm2
Figure 1. Generalized Gross Alpha and Gross Beta Self-Absorption Curves
4.0
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2. The same planchet can be counted for alpha and beta activities in desig-
nated instruments provided their counting chambers are capable of handling
the same size planchet.
3. It is recommended that NBS-calibrated standards be used for ascertaining
instrument efficiencies. A weightless deposit of 238^ for Q an(j a pOint
source from a standard solution of 137Cs for 0 are suggested. Source
of supply is: Standard Reference Materials Catalog, NBS Publication 260,
U. S. Department of Commerce (1974). Standards should also be prepared
in the geometry and weight ranges to be encountered in these gross
analyses.
Literature
Standard Methods for the Examination of Water and Waste Water, 13th ed.
American Public Health Association, Washington, D. C. (1971).
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RADIOACTIVE CESIUM IN DRINKING WATER
Principle of Method
Cesium carrier is added to the aqueous sample. The cesium is collected
as the phosphomolybdate and purified as Cs2PtCl£ for counting.
Procedure Time
Four samples in 5 hours.
Reagents
Ammonium phosphomolybdate, (NH4)3PMoi204o: prepared reagent
Calcium chloride, CaCl2: 3 M
Cesium carrier: 10 mg/ml
Chloroplatinic acid, H2PtCl6.6H20: 0.1 M
Ethanol, C2H5OH: 95%
Hydrochloric acid, HC1: 12 N (cone.), 6 N, 1 N
Sodium hydroxide, NaOH: 6 N^
Procedure
1. To a 1000-ml drinking water sample, add 1.0 ml cesium carrier and enough
12 N HC1 to make the solution -0.1 N HC1.
2. Slowly add 1 gram (NH.) PMo120.0 and stir ^or 30 minutes» using a magnetic
stirrer. Allow precipitate to settle for at least 4 hours, and discard
supernatant.
3. Slurry precipitate into a centrifuge tube. Centrifuge and discard
supernatant.
4. Wash precipitate with 20 ml 1 N^HCl, and discard wash solution.
5. Dissolve precipitate by dropwise addition of 3 to 5 ml 6 N NaOH. Heat
over a flame for several minutes to remove ammonium ions. (Moist pH
paper turns green as long as NH vapors are evolved.) Dilute to 20 ml
O
with water.
6. Add 10 ml 3 M CaCl and adjust to pH 7 with 6 N HC1 to precipitate
2
CaMoO.. Stir, centrifuge, and filter supernatant through Whatman #41
filter paper (or equivalent) into a 50-ml centrifuge tube.
7. Wash the precipitate remaining in the centrifuge tube with 10 ml water;
' filter through the same filter paper, and combine the wash with filtrate.
4
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Discard filter paper.
8. Add 2 ml 0.1 M H-PtCl. and 5 ml ethanol. Cool and stir in ice bath for
— Z 0
10 minutes.
9. Transfer with water to a tared glass-fiber filter. Wash with successive
portions of water, 1 N_HC1, and ethanol.
10. Dry, cool, weigh, mount, and beta count.
Calculation
Calculate the concentration, D, of the cesium activity in picocuries
per liter as follows:
D =
2.22 x EVR
where:
C = net count rate, counts/minute,
E = counter efficiency,
V = liters of sample used,
R = fractional chemical yield, and
2.22 = conversion factor from disintegrations/minute to picocuries.
Literature:
Finston, H. L., and M. T. Kinsley. The Radiochemistry of Cesium. AEC
Rept. NAS-NS-3035 (1961).
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RADIOACTIVE IODINE IN DRINKING WATER
Precipitation Method
Principle of Method
lodate carrier is added to an acidified sample of drinking water and,
after reduction with Na2S03 to iodide, the 131j ^s precipitated with
AgN03. The precipitate is dissolved and purified with zinc powder and sul-
furic acid, and the solution is reprecipitated as PdI2 for counting.
Procedure Time
Eight samples in 6 hours.
Reagents
Ammonium hydroxide, NH4OH: 6 N_
Ethanol, C2H5OH: 95%
Hydrochloric acid, HC1: 6 N^
lodate carrier, (103): 10 mg/ml
Nitric acid, HN03: 16 N^ (cone.)
Palladium chloride, PdCl2: 0.2 M
Silver nitrate, AgNOs: 0.1 M
Sodium sulfite, Na2S03: 1 M_ (freshly prepared)
Sulfuric acid, H2S04: 2 N
Zinc, powder: reagent grade
Procedure
1. To a 2000-ml drinking water sample, add 15 ml 16 N_HNO_ and 1.0 ml iodate
(10 ) carrier. Mix well.
O
2. Add 4 ml freshly prepared 1 M Na2SO_ and stir for 30 minutes.
3. Add 20 ml 0.1 M AgNO , stir for 1 hour and settle for another hour.
J
4. Decant and discard as much as possible of the supernatant. Filter the
remainder through a glass-fiber filter and discard filtrate.
5. Transfer the filter to a centrifuge tube and slurry with 10 ml water.
Add 1 gram zinc powder and 2 ml 2 N H2SO , and stir frequently for at
least 30 minutes.
6. Filter, with vacuum, through a fine-fritted glass funnel and collect
filtrate in an Erlenmeyer flask. Use a few ml water to wash both
residue and filter and add the wash to filtrate in the flask. Discard
residue.
7. Add 2 ml 6 N HC1 to the filtrate and heat. Add 1 ml 0.2 M PdCl and
—
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digest for at least 5 minutes. Centrifuge and discard supernatant.
8. Dissolve the precipitate in 5 ml 6 N^ NH OH and heat in boiling water bath.
Filter through a glass-fiber filter and collect filtrate^in a centrifuge
tube. Discard filter and residue.
9. Neutralize the filtrate with 6 N^HC1, add 2 ml additional, and heat in a
water bath. Add 1 ml 0.2 M PdCl2 to reprecipitate PdI2 and digest for
10 minutes. Cool slightly.
10. Transfer to a tared glass-fiber filter with water (Note 1). Wash
successively with 5 ml portions of water and ethanol.
11. Dry to constant weight at <100 C, mount, and beta count (Note 2).
-Calculation
Calculate the concentration, D, of the iodine activity in picocuries per
liter as follows:
D =
2.22 x EVR x A
where:
C = net count rate, counts/minute (c/m),
E = counter efficiency,
V = liters of sample used,
R = fractional chemical yield,
A = decay correction for I'lj (tj/2 = 8.06 d), and
2.22 = conversion factor from disintegrations/minute to picocuries.
Notes:
1. Ordinarily, the final Pdl2 precipitate is collected on a glass-fiber
filter and counted in a G-M system where the natural background is about
0.8 c/ra. Glass-fiber filters add about 0.5 c/m to the background so that
the Pdl2 counted this way will have about a 1.3 c/m background and a
counting efficiency of 35%. However, if the precipitate is collected on
a 0.8-y membrane filter, and dried for 30 minutes at 70°C, it is possible
to count the Pdl2 in a beta-gamma coincidence scintillation system where
the background coincidence count is less than 0.1 c/m and the counting
efficiency is greater than 40% (see Brauer et al. reference).
2. Confirmation of half-life of 131I and indication of purity of the
analysis can be made by recounting the planchet in approximately 1 week.
Literature:
Brauer, F..P., J. H. Kaye, and R. E. Connaly. X-ray and 6-y Coinci-
dence Spectrometry Applied to Radiochemical Analysis of Environmental
Samples. Advances in Chemistry Series, No. 93, Radionuclides in the
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Environment, pp. 231-253. American Chemical Society (1970).
Kleinberg, J., and G. A. Cowan. The Radiochemistry of Fluorine, Chlorine,
Bromine and Iodine. AEG Rept. NAS-NS-3005 (I960).
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RADIOACTIVE IODINE IN DRINKING WATER
Distillation Method
Principle of Method
Iodine carrier is added to a drinking water sample, which is acidified
to effect volatilization of iodine when distilled into a caustic solution.
The distillate is acidified and the iodine is extracted into CCl^. After
back extraction, the iodine is purified as Agl or Pdl2 for counting.
Procedure Time
Two samples in 6 hours.
Reagents
Ammonium hydroxide, Nf^OH: 15 N^ (cone.)
Carbon tetrachloride, CC14
Diethyl ether, (^2%)20: anhydrous
Ethanol, C2H5OH: 95%
Iodide carrier: 20 mg/ml.
Nitric acid, HN03: 16 N_ (cone.), 4 N_, 0.2 N^
Silver nitrate, AgN03: 0.1 M
Sodium bisulfite, NaHS03: 1 M
Sodium hydroxide, NaOH: 0.5 N^
Sodium nitrite, NaN02' 1 M_
Sulfuric acid, H2S04: 12 N^
Tartaric acid, C4H606: 50%
Procedure
1. To a 2000-ml drinking water sample in a 3-liter round-bottom flask, add
15 ml 50% C H 0 and 1.0 ml iodide carrier. Mix well, cautiously add
4 D D
25 ml cold 16 N^ HNO_, and close the distillation apparatus (Fig. 2)
(Note 1).
2. Connect an air line to the inlet, adjust the flow rate to about 2
bubbles/second, then distill for at least 15 minutes into 15 ml 0.5 N^
NaOH. Cool and transfer the NaOH solution to a 60-ml separatory funnel.
Discard the solution in the round-bottom flask.
3. Adjust the distillate solution to slightly acid with 1 ml 12 N_H SO
and oxidize with 1 ml 1 M NaNO . Add 10 ml CC1 and shake for 1 to 2
minutes. Draw off organic layer into a clean 60-ml separatory funnel
containing 2 ml 1 M NaHSO_.
4. Add 5 ml CC1 and 1 ml 1 M NaNO to the original separatory funnel
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containing the aqueous layer and shake for 2 minutes. Combine the
organic fraction with that in the separator/ funnel in step 3.
5. Repeat step 4 and discard the aqueous layer.
6. Shake separatory funnel thoroughly until CC1. layer is decolorized;
allow phases to separate and transfer aqueous layer to a centrifuge tube.
7. Add 2 ml 1 M NaHSO to separatory funnel which has the CC1 and shake for
O ^r
several minutes. When the phases separate, combine this aqueous layer
with that in centrifuge tube from step 6.
8. Add 1 ml water to separatory funnel and shake for several minutes. When
the phases separate, add aqueous layer to the same centrifuge tube.
Discard organic layer. (Note 2).
9. To the combined aqueous fractions, add 2 ml 0.1 M^ AgNO plus 4 ml HNO,.
Stir for 1 minute then allow to stand 30 minutes at room temperature to
coagulate silver iodide. Centrifuge at high speed for 10 minutes.
Carefully decant and discard supernatant.
10. Pipet 5 ml 15 N^ NH OH into the centrifuge tube and stir thoroughly for
several minutes. Heat carefully while stirring until boiling begins.
Centrifuge at high speed for 10 minutes. Carefully decant and discard
supernatant.
11. Slurry precipitate in 10 ml water, add 1 ml 4 N HNO , stir and immedi-
ately transfer precipitate to tared glass-fiber filter. Filter slowly
at first to prevent loss.
12. Wash precipitate on filter successively with 20 ml 0.2 N^ HNO,, 20 ml
ethanol and 20 ml diethyl ether. Let dry with suction at least
10 minutes. Store in desiccator.
13. Weigh, mount, and store in light-tight container until ready to beta
count.
Calculation
Calculate the concentration, D, of the iodine activity in picocuries
per liter as follows:
D =
2.22 x EVR x A
where:
C = net count rate, counts/minute,
10
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18/9 Socket
20/40 § Joint
3000ml Flask
Still
Delivery
Tube
Figure 2. Distillation Apparatus for Iodine Analysis
11
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E = counter efficiency,
V = liters of sample used,
R = fractional chemical yield,
A = decay correction for 131i (t\/2 - 8.06 d), and
2.22 = conversion factor from disintegrations/minute to picocuries.
Notes:
1. A distillation apparatus such as shown in Figure 2 or equivalent can be
used: a round-bottom flask fitted with a ground-glass joint that allows
for a source of air to be bubbled into the .sample and that has a delivery
tube on the other end extending into a caustic trap.
2. An alternate method, whereby the iodide is precipitated as Pdl2> provides
a means for measuring radioiodine with less interference from chlorides.
The procedure, after step 8, would then be:
a. To the combined aqueous fractions, add 2 ml 6 N_ HC1 and heat. Add
2 ml 0.2 M PdCl2 and digest for at least 5 minutes. Centrifuge and
discard supernatant.
b. Transfer to a tared glass-fiber filter with water. Wash twice with
5-ml portions of water and ethanol.
c. Dry to constant weight at 70 to 90°C, mount, and beta count.
Literature:
1972 Book of ASTM Standards, Part 23. American Society for Testing and
Materials, Philadelphia, Pa. D 2334-68 (1972).
12
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ALPHA-EMITTING RADIUM ISOTOPES IN DRINKING WATER
Precipitation Method
Principle of Method
The radium in the drinking water sample is coprecipitated with barium as
the sulfate and purified by reprecipitation from EDTA solution. The BaS04
precipitate containing 226Ra, 224Ra and 223Ra is counted for alpha activity.
Procedure Time
One sample in 6 hours; four samples in 8 hours.
Reagents
Acetic acid, CH3COOH: 17.4 N_ (glacial)
Ammonium hydroxide, NF^OH: 15 N_ (cone.), 2 N_
Barium carrier: 16 mg/ml
Citric acid, C6H807.H20: 1 M
EDTA reagent: prepared reagent
Indicator, methyl orange: 0.1%
Lead carrier: 15 mg/ml
Sulfuric acid, H2S04: 18 N
Sodium hydroxide, NaOH: 6 N_
Procedure
1. To a 1000-ml drinking water sample, add 5 ml 1 M C,H00 .H 0, 2.5 ml 15 N
— D o / 2
NH OH, 1 ml lead carrier, and 2.0 ml barium carrier.
2. Heat the solution to boiling and add 10 drops of methyl orange indicator.
3. Add, with stirring, 18 N_ H_SO to a permanent pink color and then 0.5 ml
in excess.
*
4. Digest 5 to 10 minutes and let the mixed BaSO -PbSO precipitate settle
overnight. Decant and discard supernatant.
5. Transfer the precipitate to a centrifuge tube with a minimum amount of
water. Centrifuge and discard supernatant.
6. Dissolve the precipitate by adding 15 ml EDTA reagent; heat in a water
bath until clear. If not entirely clear, continue heating and add a
few drops of 6 N^ NaOH.
7. Add 2 ml 17.4 N CH COOH dropwise and digest 5 to 10 minutes (Note 1).
Centrifuge, discard the supernatant, and record tints (Note 2).
8. Wash the B.aSO precipitate containing the radium with 15 ml 2 N^ NH OH.
Centrifuge and discard wash.
13
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9. Wash the BaS04 precipitate with 10 ml water, centrifuge, and discard wash.
10. Transfer the precipitate to a tared stainless-steel planchet with a
minimum of water, and dry under infra-red lamps (Note 3).
11. Cool, weigh, and store in desiccator.
12. Determine the alpha activity in an internal proportional counter (Note 4),
Calculation
Calculate the concentration, D, of the 226Ra activity (which would
include any 22^Ra and 223Ra that is present) in picocuries per liter as
follows:
D =
2.22 x EVR x IW
where:
C = net count rate, counts/minute,
E = counter efficiency for alpha counting,
V = liters of sample used,
R = fractional chemical yield,
I = ingrowth factor (Note 5),
W - self-absorption factor, and
2.22 = conversion factor from disintegrations/minute to picocuries.
Notes:
This volume of acetic acid gives a pH of about 4.5 and is sufficient to
destroy the Ba-EDTA, but not the Pb-EDTA, complex.
At this step of the procedure, radon (and daughters) grows into the
precipitate.
Drying should be rapid but not too vigorous to minimize loss of 222Rn
that has already grown into the precipitate.
Alpha self-absorption losses for 226Ra in an internal proportional
counter as a function of sample thickness are:
Sample thickness, Relative efficiency losses,
mg/cm2 %
0.0 0.00
0.31 0.04
0.95 0.06
1.26 0.12
1.55 0.14
1.90 0.19
1.97 0.20
2.20 0.22
2.65 0.30
3.14 0.37
14
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Although this procedure utilizes an internal proportional counter to deter-
mine alpha activity, it can be modified so that the final precipitate
(step 9) is filtered on tared Whatman #42 filter paper, dried, weighed, and
covered with an alpha phosphor and Mylar. After storing for 30 days, the
226fta in the sample can be determined with an alpha scintillation counter.
5. The ingrowth factor can be calculated from Kirby's data (see Kirby, H. W.
reference). Some of these alpha activities from initially pure 226ga
during the first 240 hours are:
Hours Ingrowth factor
0 1.0000
1 1.0160
2 1.0363
3 1.0580
4 1.0798
5 1.1021
6 1.1238
24 1.4892
48 1.9054
72 2.2525
96 2.5422
120 2.7838
144 2.9853
192 3.2939
240 3.5086
Literature:
Goldin, A. S. Determination of Dissolved Radium. Anal. Chem. 33,
406-409 (March 1961).
Harley, J. H.7 ed. Manual of Standard Procedures, USAEC Rept. HASL 300
(1972).
Kirby, H. W. Decay and Growth Tables for the Naturally Occurring
Radioactive Series. Anal. Chem. 26, 1063-1071 (1954).
15
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RADIUM-226 IN DRINKING WATF.R
Radon Emanation Technique
Principle of Method
The radium in the drinking water sample is concentrated and separated
by coprecipitation with barium as the sulfate. The precipitate is dissolved
in EDTA reagents, placed in a sealed bubbler, and stored for ingrowth of
222Rn.
Procedure Time
Four samples in 8 hours.
Equipment
Radon Emanation Apparatus with Scintillation Cell (Pig- 3).
Reagents
Ammonium hydroxide, NH4OH: 15 N (cone.)
Ascarite: drying reagent, 8-20 mesh
Barium carrier: 16 mg/ml
EDTA reagent: 0.25 M
Helium gas
Hydrochloric acid, HC1: 12 N_ (cone.)
Magnesium perchlorate, Mg(C104)2: reagent grade
Sulfuric acid, H2S04: 18 N_, 0.1 N
Standard radium-226 solution: 50 pCi/ml
Procedure
1. To a 1000-ml drinking water sample, add 20 ml 12 N^ HC1 and 2.0 ml barium
carrier and heat to boiling.
2. Cautiously and with vigorous stirring, add 20 ml 18 N H2S04. Digest 5
to 10 minutes and let precipitate settle overnight. Decant and discard
supernatant.
3. Slurry the precipitate and transfer to a centrifuge tube with a minimum
amount of 0.1 N H2S04. Centrifuge and discard supernatant. Wash twice
with 0.1 N_ H2S04 and discard washes.
4. Add 20 ml EDTA reagent, 2 drops 15 N_NH4OH and heat in a water bath until
the precipitate dissolves (Note 1).
5. Transfer the solution to a radon bubbler (Fig. 4). Open both the upper
and lower stopcocks and de-emanate the solution by slowly passing helium
gas through the bubbler for about 20 minutes.
16
-------
-Scintillation Cell
\J
Manometer, I I/2mm, 1.0.
Capillary T-Tube
Thermometer Capillary
Anhydrous Magnesium Perchlorate
Ascarite (8-20 mesh)
Aged Air From Compressed
Air Regulator
Radon Bubbler
Mercury Reservoir
Figure 3. Radon Emanation Apparatus with Scintillation Cell
17
-------
7mm O.D.
Corning No. 2
or Equivalent
Bubble Trap
7 mm 1.0.
Rigidity Brace
7mm Capillary Tubing
M/2 mm I.D.
Fritted Gloss Disc
10-15 micron pores
Volume to be kept
at minimum
Figure 4. A Typical Radon Bubbler (emanation tube)
18
-------
6. Close the two stopcocks, and record time. Store the solution for 4 to
O O *^
8 days for ingrowth of Rn (Pig- 5).
7. At the end of the storage period, fill the upper half of an absorption
tube with magnesium perchlorate and the lower half with Ascarite (Note 2),
Attach the tube to the radon bubbler and then attach the evacuated
scintillation cell (Fig. 6) to the tube.
8. Open the stopcock on the cell and check the assembly for leaks. Gradually
open the outlet stopcock on the bubbler, and when the stopcock is fully
open and no further significant bubbling takes place, close the stop-
cock.
9. Adjust the helium gas pressure so that the gas flows at slightly above
atmospheric pressure.
10. Connect the hose to the bubbler inlet and gradually open the inlet
stopcock using the bubbling as a guide. When the stopcock can be fully
opened without a significant amount of bubbling, the bubbler is
essentially at atmospheric pressure again.
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.
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, disconnect the
tubing from the bubbler inlet and close the inlet and outlet stopcocks
of the cell and bubbler, and record time. This the beginning of Rn
222
decay and ingrowth of Rn daughters.
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 Rn (Note 3).
Calculation
yj (L
Calculate the concentration, D, of the Ra activity in picocuries per
liter as follows:
Xt
n C 1 1
D = x r— x —rr— x
2.22 EV 1-e-^l e
19
-------
N)
O
1.0
0.9
0.8
0.7
CT
^0.5
° 0.4
| 0.3
o
o
£0.2
O.I
0.0
0
10
Days
15
20
Figure 5. The Growth of Radon-222 from Radium-226
-------
67mm
90mm
Phosphor
^Coated
Clear Silica
Window
Corning No. 2
or Equivalent
Brass Collar
Kovar Metal
£J 50 mm
Figure 6. A Typical Scintillation Cell for Radon Counting
21
-------
where:
C = net count rate, counts/minute (Note 4),
E = calibration constant for the de-emanation system and the scintillation
cell in counts per minute/disintegrations per minute of 222Rn (Note 5),
V = volume of sample in liters,
t-^ = the elapsed time in days between the first and second de-emanations
(steps 6 and 12) and X is the decay constant of 222Rn (0.181 d-1),
t2 = the time interval between the second de-emanation and counting and X
is the decay constant of 222Rn (0.00755 hr"1), and
tj = the counting time in minutes and X is the decay constant of 222Rn
(1.26 x 10-4 min'1).
Notes:
1. The volume of these bubblers is usually greater than 20 ml allowing for
at least a 1 cm air space between the bubbler and the stopper. In those
instances where the solution volume exceeds the capacity of the bubbler,
it will be necessary to continue the boiling in the water bath until the
volume is reduced.
2. For minimizing corrections that would be required in subsequent calcula-
tions, the voids above the bubbler must be kept very small. Capillary
tubing should be used whenever possible, and the drying tube volume with
the Ascarite and magnesium perchlorate must be kept to a minimum. A
typical system consists of a drying tube 10 cm x 1.0 cm (I.D.), with
each of the drying agents occupying 4 cm and being separated by small
glass wool plugs. The column can be reused several times before the
chemicals need to be replaced.
3. After each analysis, flush the cell three times by evacuation 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.
4. Before each analysis, the scintillation cell should be evacuated, filled
with helium and counted to ascertain the cell background.
5. The calibration constant, E, is determined as follows:
a. Place 50 pCi of the 22^Ra standard solution in a bubbler (50 pCi
of 226Ra will produce about 6 pCi 222Rn in 18 hours). Attach the
bubbler to the assembly as shown in Fig. 3.
b. With the scintillation cell disconnected, bubble helium gas through
the solution for 20 minutes.
c. Close both stopcocks on the bubbler to establish zero time for
ingrowth of 2"Rn. Set aside for approximately 18 hours.
d. Evacuate the scintillation cell and attach to the column and
bubbler.
e. Proceed with steps 8-13, Radon Emanation Technique, p. 19.
f. The calibration constant, E, is determined from the 226Ra activity
in the bubbler and the ingrowth time of 222Rn by the equation:
22
-------
A (l-e~Atl)(e~At2)
where:
C = net count rate, counts/minute,
A = activity of 226Ra in the bubbler (d/m),
t, = ingrowth time of 222Rn in hours,
t2 = decay time of 222Rn ^n hours occurring between de-emanation and
counting, and
X = decay constant of 222Rn, 0.00755 hour'1.
The calibration constant, E, includes the de-emanation efficiency of the
system, the counting efficiency of the cell, and the alpha activity contri-
buted by 218p0 and 214pO) which will be in equilibrium with 222Rn when the
sample is counted 4 hours after the de-emanation. A 100-minute counting
time will be sufficient for the standard and will eliminate the need to
correct for decay of 222Rn, which occurs during counting.
The bubbler used for the 22^Ra standardization should not be used for
sample analysis. It should be set aside to be retained for future calibra-
tions. Each scintillation cell should be calibrated periodically with the
22fy*a standard to ensure instrument quality control.
Literature:
Blanchard, R. L. Uranium Decay Series Disequilibrium in Age Determina-
tion of Marine Calcium Carbonates. Doctoral Thesis, Washington
University, St. Louis, Mo. (June 1963).
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).
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).
23
-------
RADIUM-228 IN DRINKING WATER
Sequential Method Radium-228/Radium-226 '
Principle of Method
The 22°Ra an(j 22&Ra in tne drinking water sample are concentrated and
separated by coprecipitation with barium and lead as sulfates and purified
by EDTA-chelation. After 36-hour ingrowth of actinium-228 from radium-228,
the 228^c is carried on yttrium oxalate, purified and beta counted. The
radium-226 in the supernatant is either precipitated as the sulfate, purified
and alpha counted (see step 20) > or is transferred to a radon bubbler and
determined by emanation (see step 27).
Procedure Time
Two samples in 12 hours.
Reagents
Acetic acid, HC2H302: 17.4 N^ (glacial)
Acetone, (CH3)2CO: anhydrous
Ammonium hydroxide, NH^OH: 15 N^ (cone.)
Ammonium oxalate, (NH4) 2C204. ^2®'- ^%
Ammonium sulfate, (NH4)2S04: 200 mg/ml
Ammonium sulfide, (NH4)2S: 2%
Barium carrier: 16 mg/ml
Citric acid, C^H807 .H20: 1 M
EDTA reagent: 0.25 M
Ethanol, C2H50H: 95%
Indicator, methyl orange: 0.1%
Lead carrier: 15 mg/ml, 1.5 mg/ml
Nitric acid, HN03: 16 N (cone.), 6 N, 1 N
Sodium hydroxide, NaOH: 18 N_, 10 N, 1 N_
Strontium-yttrium mixed carrier: 0.9 mg/ml Sr+2_o.9 mg/ml Y'1"3
Sulfuric acid, H2S04: 18 N^
Yttrium carrier: 18 mg/ml, 9 mg/ml
Procedure
1. For each liter of drinking water, add 5 ml 1 M C H O-.H 0 and a few drops
DO' £
methyl orange indicator. The solution should be red (Note 1).
2. Add 10 ml lead carrier (15 mg/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.
3. Add 15 N_ NH^OH until a definite yellow color is obtained, then add a
few drops excess. Precipitate lead and barium sulfates by adding 18 N^
24
-------
H SO until the red color reappears, then add 0,25 ml excess. Add 5 ml
(NH ) SO (200 mg/ml) for each liter of sample. Stir frequently and
keep at a temperature of about 90 C for 30 minutes.
4. Cool slightly, then filter with suction through a 47-mm metricel
membrane filter (GA-6,0.45 y-pore size). Make a quantitative transfer
of precipitate to the filter by rinsing last particles out of beaker
with a strong jet of water.
5. Carefully place filter with precipitate in the bottom of a 250 ml beaker.
Add about 10 ml 16 N^ HNO, and heat gently until the filter completely
dissolves. Transfer the precipitate with the aid of more 16 N_ HNO
~ O
into a polypropylene centrifuge tube. Centrifuge and discard
supernatant.
6. Wash the precipitate with 15 ml 16 N HNO_, centrifuge, and discard
o
supernatant.
7. Repeat step 6.
8. Add 25 ml EDTA reagent, heat in a hot water bath, and stir well. Add a
few drops 10 N_ NaOH if the precipitate does not readily dissolve.
9. Add 1 ml strontium-yttrium mixed carrier and stir thoroughly. Add a
few drops 10 N_ NaOH if any precipitate forms.
10. Add 1 ml (NH ) SO (200 rag/ml) and stir thoroughly. Add 17.4 N
HC.H 0 until barium sulfate precipitates, then add 2 ml excess. Digest
£* J £,
in a hot water bath until precipitate settles. Centrifuge and discard
supernatant.
11. Add 20 ml EDTA reagent, heat in a hot water bath, and stir until precipi-
tate dissolves. Repeat steps 9 and 10. (Note time of last barium
228
sulfate precipitation; this is the beginning of the Ac ingrowth time.)
12. Dissolve the precipitate in 20 ml EDTA reagent as before, then add 1.0 ml
yttrium carrier (? mg/ml) and 1 ml lead carrier (1.5 mg/ml). If any
precipitate forms, dissolve by adding a few drops 10 N_ NaOH. Cap the
polypropylene tube and age at least 36 hours.
13. Add 0.3 ml (NH ) S and stir well. Add 10 N_ NaOH dropwise with vigorous
stirring until lead sulfide precipitates, then add 10 drops excess. Stir
intermittently for about 10 minutes. Centrifuge and decant supernatant
into a clean tube.
14. Add 1 ml lead carrier (1.5 mg/ml), 0.1 ml (NH.) S, and a few drops 10 N
25
-------
NaOH. Repeat precipitation of lead sulfide as before. Centrifuge and
filter supernatant through Whatman #42 filter paper into a clean tube.
Wash filter with a few ml water. Discard residue.
15. Add 5 ml 18 N^NaOH (make at least 2 normal in OH~). Stir well and
digest in a hot water bath until yttrium hydroxide coagulates. Centri-
fuge and decant supernatant into a beaker. Cover beaker and save
supernatant for Ra analysis, step 20 or 27. (Note time of yttrium
228
hydroxide precipitation; this is the end of the Ac ingrowth time and
228
beginning of Ac decay time.)
16. Dissolve the precipitate in 2 ml 6 N^HNO . Heat and stir in a hot water
O
bath about 5 minutes. Add 5 ml water and reprecipitate yttrium hydroxide
with 3 ml 10 N^ NaOH. Heat and stir in a hot water bath until precipitate
coagulates. Centrifuge and discard supernatant.
17. Dissolve precipitate with 1 ml 1 N_ HNO, and heat in hot water bath a
few minutes. Dilute to 5 ml and add 2 ml 5% (NH ) C 0 .H 0. Heat to
^r £, £• ^ £
coagulate, centrifuge and discard supernatant.
18. Add 10 ml water, 6 drops 1 N HN03 and 6 drops 5% (NH^C^.^O. Heat
and stir in a hot water bath a few minutes. Centrifuge and discard
supernatant.
19. 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 (Note 2).
Alpha-Emitting Radium Isotopes By Precipitation
20. To the supernatant from step 15, add 4 ml 16 f£ HNO and 2 ml (NH ) SO
(200 mg/ml), stirring well after each addition. Add 17.4 N^HC?H 0
until barium sulfate precipitates, then add 2 ml excess. Digest on a
hot plate until precipitate settles. Centrifuge and discard supernatant.
21. Add 20 ml EDTA reagent, heat in a hot water bath, and stir until
precipitate dissolves. Add a few drops 10 N^ NaOH if precipitate does
not readily dissolve
22. Add 1 ml strontium-yttrium mixed carrier, and 1 ml lead carrier
(1.5 mg/ml); stir thoroughly. Add a few drops 10 N^NaOH if any precipi-
tate forms.
23. Add 1 ml (NH4)2S04 (200 mg/ml) and stir thoroughly. Add 17.4 N^
26
-------
until barium sulfate precipitates, then add 2 ml excess. Digest in a
hot water bath until precipitate settles. Centrifuge and discard
supernatant.
24. Wash precipitate with 10 ml water. Centrifuge and discard supernatant.
25. Transfer precipitate to a tared stainless-steel planchet with a minimum
amount of water. Dry under an infra-red lamp and weigh (Note 3).
26. Count immediately in an alpha proportional counter.
Radium-226 - By Radon Emanation
27. To the supernatant from step 15, proceed with steps 20 to 25. Care-
fully transfer barium sulfate from planchet with the aid of a rubber
policeman and 14 ml EDTA reagent into a small beaker. Add a few drops
10 N^ NaOH and heat to dissolve. Cool and transfer to a radon bubbler
(Figure 4), rinsing beaker with another ml EDTA reagent, and proceed with
Radium-226 in Drinking Water - Radon Emanation Technique, page 16, step 5,
Calculation for 228Ra
Calculate the concentration, D, of 228Ra in picocuries per liter as
follows:
C Xt2
D = ^ x <•
2.22 x EVR (1-e Xt2)*
where:
C = average net count rate, counts/minute,
E = counter efficiency, for 228Ac,
V = liters of sample used,
R = fractional chemical yield of yttrium carrier (step 19) multiplied by
fractional chemical yield of barium carrier (step 25),
2.22 = conversion factor from disintegrations/minute to picocuries,
X = the decay constant for 228Ac (0.001884 min-1),
tj = the time interval (in minutes) between the first yttrium hydroxide
precipitation in step 15 and the start of the counting time,
t2 = the time interval of counting in minutes, and
ts = the ingrowth time of 228Ac in minutes measured from the last barium
sulfate precipitation in step 11 to the first yttrium hydroxide
precipitation in step 15.
,,_ -Xt2-« is a factor to correct the average count rate to count rate at
beginning of counting time.
27
-------
Calculation for Alpha-Emitting Radium Activity
a) by precipitation, refer to Alpha-Emitting Radium Isotopes in Drinking Water
Precipitation Method, page 14, b) by radon emanation, refer to Radium-226
in Drinking Water Radon Emanation Technique, page 19.
Notes:
1. At the time of sample collection add 2 ml 16 N^ HN03 for each liter of
water.
2. If the 226Ra analysis is not desired, complete step 20 and then steps
24 and 25 to obtain the fractional barium yield for calculating 228Ra
activity.
3. If after sufficient beta decay of the actinium fraction, it is determined
that there is no Ra in the sample, then the 226Ra fraction may be
alpha counted directly. If 228Ra is present, then the 226Ra must be
determined by radon emanation.
Literature:
Johnson, J. 0. Determination of Radium-228 in Natural Waters. Radio-
chemical Analysis of Water, Geological Survey Water - Supply Paper
1696-G., U. S. Govt. Printing Office, Washington, D. C. (1971).
28
-------
RADIOACTIVE STRONTIUM IN DRINKING WATER
Principle of Method
Strontium carrier is added to the drinking water sample, collected as
the soluble carbonate, and separated from most of the calcium as the nitrate.
Impurities are removed by an hydroxide scavenge. After the barium is
removed as the chromate, the strontium is purified as SrC03 for counting.
Procedure Time
Four samples in 6 hours.
Reagents
Ammonium acetate -buffer, (CH3COOH-CH3COONH4): pHS.O
Ammonium hydroxide, NH40H: 15 N_ (cone.), 6 N_
Barium carrier: 16 mg/ml
Ethanol, C2H5OH: 95%
Hydrochloric acid, HC1: 1 N^
Indicator, methyl red: 0.1%
Iron chloride, FeCl3: 0.1 M_
Nitric acid, HN03: 16 N (cone.), 6 N_, 1 N^
Oxalic acid, ^0204: saturated
Sodium carbonate, Na2C03: 1.5 M
Sodium chromate, Na2Cr04: 0.5 M
Sodium hydroxide, NaOH: 6 N^
Strontium carrier: 20 mg/ml
Yttrium carrier: 10 mg/ml
Procedure
1. To a 1000-ml drinking water sample, add 1.0 ml strontium carrier and 1 ml
barium carrier.
2. Make basic with 5 to 10 ml 6 N^ NaOH and heat to boiling.
3. Add 5 ml 1.5 M Na CO , stir, and digest until SrCO coagulates, cool,
z, o o
centrifuge, and discard supernatant.
4. Wash precipitate with 15 ml water and discard wash solution.
5. Dissolve precipitate with 1 ml 6 N^ HNO .
o
6. Add 25 ml 16 N^ HNO,, stir, and cool in an ice bath 5 minutes.
7- Centrifuge, discard supernatant, and let drain a few minutes (Note 1).
8. Dissolve precipitate with 10 ml water and add 0.5 ml 0.1 M_ FeCl .
* O
9. Heat to near boiling in water bath and add 6 N^ NH.OH dropwise until
Fe(OH)3 precipitates.
29
-------
10. Cool, centrifuge, and transfer supernatant to a clean centrifuge tube.
Discard precipitate. Note time of last precipitation; this is the
beginning of yttrium ingrowth. (Complete steps 11 through 18 without
90
delay to minimize ingrowth of Y.)
11. Add 3 drops methyl red indicator, and adjust pH to near 5 with a few
drops 1 N_HC1. (Color change is from yellow to red.)
12. Add 5 ml ammonium acetate buffer solution and heat in water bath.
13. Slowly add 1 ml 0.5 M Na CrO . Stir, heat, and centrifuge. Transfer
supernatant to a clean centrifuge tube; discard residue.
14. Add 2 ml 15 N^ NH OH to the supernatant, heat in water bath, and slowly
add, with stirring, 5 ml 1.5 M Na CO . Digest until precipitation is
Z o
complete, cool, centrifuge, and discard supernatant.
15. Dissolve precipitate with 5 ml 1 N_ HC1, add 10 ml water, and repeat
step 14.
16. Wash the strontium carbonate precipitate with 20 ml water, and discard
wash solution.
17. Slurry the precipitate with minimum of water and transfer to a tared
stainless-steel planchet. Dry under infra-red lamps.
18. Cool, weigh, and beta count immediately (Note 2).
Calculation
Calculate the concentration, D, of the strontium activity in picocuries
per liter as follows:
D =
2.22 x EVR
where :
C = net count rate, counts /minute,
E = counter efficiency,
V = liters of sample used,
R = fractional chemical yield, and
2.22 = conversion factor from disintegrations/minute to picocuries.
Notes:
If the drinking water samples contain much CaC03 (hardness), it will be
necessary to repeat steps 5, 6, and 7 until it is all eliminated from
the Sr(NC>3)2 precipitate.
The counting result, immediately ascertained, represents the total
strontium activity (90Sr + 89Sr) plus an insignificant fraction of the
30
-------
90Y that has grown in from the separated 90Sr. To determine the 89Sr
and 90sr with a greater precision, the planchet should be stored at
least 2 weeks so that the 90Sr-90Y activity will be in equilibrium.
At this point, steps 19-39 are performed on the precipitate to separate
the yttrium from the strontium and determine the ™Sr activity.
90
19. After the period for Y 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 1 N_ HNOj. Dissolve the
precipitate in the tube with sufficient 1 N_ HNO , and dilute with water
to 10 ml.
20. Add 1.0 ml yttrium carrier and stir.
21. Boil to expel dissolved carbon dioxide; cool to room temperature.
22. Replace in water bath and make basic with 2 to 3 ml 15 N_ NH OH. Stir
and digest until the yttrium hydroxide precipitation is complete.
23. Cool, centrifuge, and decant supernatant into a 100-ml beaker. Note
ti'me of last precipitation; this is the end of 9^Y ingrowth and the
beginning of Y decay.
24. Dissolve precipitate in 1 ml 1 N_ HNO, and dilute with water to 10 ml.
25. Reprecipitate yttrium by dropwise addition of 15 N_ NH OH.
26. Centrifuge and combine supernatant with solution in the 100-ml beaker
(step 23).
27. Repeat steps 24, 25, and 26. Save the combined supernatant solutions in
the beaker for strontium activity and gravimetric yield determination,
step 35 (Note 3).
28. Add 2 ml 1 N HNO, to the Y(OH)_ precipitate from step 26 and dissolve.
— 6 3
Dilute to 5 ml with water. Filter through Whatman #42 filter paper and
collect filtrate in a centrifuge tube.
29. Slowly add 5 ml saturated H C 0 , with stirring, and digest in hot-water
bath for 10 minutes.
30. Cool in an ice bath to room temperature.
31. Centrifuge and discard supernatant.
32. Wash precipitate twice with 10 ml hot water. Centrifuge and discard
wash solutions.
33. Filter the yttrium oxalate on a tared glass-fiber filter. Wash with
hot water and ethanol.
31
-------
90
34. Dry, cool, weigh, mount, and beta count the Y immediately.
35. Warm the combined supernatant solution from step 21 - add 5 ml 1.5 M
Na2CO , and digest for 10 minutes.
36. Cool, centrifuge, and discard supernatant.
37. Wash the SrCO with 15 ml water and discard wash solution.
38. Slurry with a few ml water and transfer quantitatively to a tared
stainless-steel planchet. Dry under infra-red lamps.
39. Cool, weigh, and beta count immediately.
Calculation
Calculate the concentration of 89gr and 90Sr in picocuries per liter
as follows:
, 90.., / , ,, c/m
1. Y c/m (corrected) =
A x BI x C
90 . 90V , , . ,. D
Sr c/m = Y c/m (corrected) x =•
Qfl
90V , Y c/m (corrected) x G x B2
Y c/m = £_
89C . ,D 90C , 90V , . 1
Src/m= (R - Sr c/m - Y c/m) p-
900 .. .. 90Y c/m (corrected)
Sr activity = 2.22 xEIV
8Q
89C .. .. Sr c/m
Sr activity =
2.22 x HIV
where :
A = decay factor for Y from step 23 to counting time,
Bj = ingrowth factor of 9^Y from time of strontium purification to yttrium
separation,
B2 = ingrowth factor of 90y from time of yttrium separation to time of total
strontium count,
C = fractional chemical yield for yttrium,
D = 9°Sr efficiency for counter in which radiostrontium is counted,
E = 90y efficiency for counter in which 90y is counted,
F = decay factor for 89Sr from sample collection to counting time,
G = 90y efficiency for counter in which radiostrontium is counted,
H = 89sr efficiency for counter in which radiostrontium is counted,
I = fractional chemical yield for strontium,
R = observed count rate of total radiostrontium fraction (steps 18 or 39),
V = liters of sample used, and
2.22 = conversion factor from disintegrations/minute to picocuries.
32
-------
Note:
3. Steps 35-39 are a repeat of the strontium carbonate precipitation to
determine chemical yield after the yttrium has been removed. The beta
activity should be comparable to that obtained previously for the
precipitate from step 18. It is a more accurate result, however, since
the only correction that need be made is that for the ingrowth of ^Oy
from the time of yttrium separation (step 27) to the time of the total
strontium count.
Literature:
Douglas, G. S., ed. Radioassay Procedures for Environmental Samples,
Environmental Health Series, USDHEW Rept. 999-RH-27, National Center
for Radiological Health, Rockville, Md. 10852 fJan. 1967).
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)..
33
-------
TRITIUM IN DRINKING WATER
Principle of Method
The aqueous sample is distilled to dryness to effect quantitative trans-
fer of tritium to the distillate and to remove interfering radionuclides and
quenching materials. A portion of the distillate is mixed with scintillation
solution and counted in a liquid scintillation spectrometer. Standard
tritium and background samples are prepared and counted alternately to nullify
errors produced by aging of the scintillation medium or instrument drift.
Procedure Time
Four samples in 2 hours.
Reagents
Scintillation solution: prepared reagent
Tritium, ^H: standard tracer solution
Procedure
1. Distill the drinking water sample (50 ml or less) to dryness (Fig. 7)
and collect the distillate in a centrifuge tube (Note 1).
2. Transfer 16 ml scintillation solution to a 25-ml scintillation vial.
3. Add 4 ml sample distillate to the scintillation vial, cap tightly,
and^ shake until thoroughly mixed.
4. Prepare a background sample consisting of 4 ml water of minimal tritium
concentration and 16 ml scintillation solution in same manner as sample.
5. Prepare a standard consisting of 16 ml scintillation solution and 4 ml
water, which contains a standard concentration of tritium activity in
same manner as sample.
6. Dark-adapt and cool sample, background, and standard solutions in
instrument freezer to prepare for counting (Note 2).
7. In normal counting operation, tritium is counted with a window setting
where the figure of merit is at maximum (Note 3). The high voltage is
set to obtain the peak counting efficiency in the window.
To confirm the purity and identify the tritium activity the following
steps are necessary:
8. Determine the count rate for each sample, background and standard. Three
successive results which are within 2 sigma of each other, ensure that
34
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50-ml
CENTRIFUGE TUBE
IN HOLDER
100 - ml
DISTILLING
FLASK
J
Figure 7. Distillation Apparatus for Tritium Analysis
-------
the vials have been dark adapted.
9. With a 2-channel spectrometer, one window is set to give the best figure
of merit and the other is set as an impurity screen. The ratios of the
activity for the H standard and for the distilled samples should be
the same at the two window settings. If not, the samples must be
redistilled to remove interfering ionizing radiations and prepared
again for counting.
Calculation
Calculate the concentration, D, of the tritium activity in picocuries
per liter as follows:
D = C x 1000
2.22 x EV
where:
C = net count rate, counts/minute,
E = efficiency for measuring ^H in liquid scintillation spectrometer,
V = milliliters of sample used,
2.22 = conversion factor from disintegrations/minute to picocuries.
Calculate the efficiency, E, for measuring ^H in the liquid scintillation
spectrometer as follows:
-I
where:
Y = counts/minute determined by counting standard tritium sample (step 5)
at the optimum instrument settings, and
S = standard tritium activity (disintegrations per minute/ml) as rated by
NBS or equivalent, corrected for decay.
Calculate the decay correction for the tritium activity as follows:
A=A e-0.693t/T
o
where:
A = activity at time t,
AQ = activity at time of collection or from the date the standard was rated,
e = base of natural logarithms,
t = elapsed time from collection or from the date the standard was rated,
and
T = half life of tritium (12.3 years).
36
-------
Notes:
As a general rule, all samples should be distilled to dryness for
quantitative recovery of tritium and to remove interfering radionuclides.
Iodine-131 in aqueous samples can be eliminated by adding stable iodine
and AgNOg to the flask before the distillation.
The freezer temperature must be maintained above 2°C or, in time, the
solution will begin to solidify. If an ambient temperature liquid
scintillation spectrometer is employed, the vial must be dark-adapted,
usually 24 to 48 hours, before counting begins.
Figure of Merit = f (Efficiency)2
6 B (Background)
Literature:
Butler, F. E. Determination of Tritium in Water and Urine. Anal. Chem.
33, 409-414 (1961).
37
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POTASSIUM-40 IN DRINKING WATER (Note 1)
Principle of Method
Total potassium in drinking water is determined by one of several
methods--atomic absorption, flame photometry, or colorimetry. From the
determination of mg/1 total potassium present, the concentration of 4(^K can
be calculated.
Preparation of Standards
Stock Solution: Dissolve 0.1907 g of KC1 (analytical reagent grade),
dried at 110°C, in deionized distilled water and
make up to 1 liter.
1 ml = 0.10 mg K (100 mg/1).
Prepare dilutions of the stock solution to be used as calibration
standards at the time of analysis.
General Instrumental Parameters for Atomic Absorption (Note 2)
Potassium hollow cathode lamp
Wavelength: 766.6 nm
Fuel: Acetylene
Oxidant: Air
Type of flame: Slightly oxidizing
Procedure
1. For determining total potassium, the drinking water sample is acidified
with 1:1 redistilled HNO, to a pH of 2 at the time of collection. The
sample is not filtered before processing.
2. Transfer a representative aliquot of the drinking water sample (50 to
100 ml) to a Griffin beaker and add 3 ml of concentrated redistilled
HNO . Place the beaker on a hot plate and evaporate to dryness cautious-
O
ly, making certain that the sample does not boil. Cool the beaker and
add another 3 ml portion of concentrated redistilled HNO . Cover the
beaker with a watch glass and return to the hot plate. Increase the
temperature of the hot plate so that a gentle reflux action occurs.
Continue heating, adding additional acid as necessary, until the
digestion is complete (generally indicated by a light colored residue).
Add sufficient distilled 1:1 HC1 and again warm the beaker to dissolve
the residue.
38
-------
3. Wash down the beaker walls and watch glass with distilled water and
filter the sample to remove silicates and other insoluble material that
could clog the atomizer. Adjust the volume to some predetermined value
based on the expected potassium concentration. The sample is now ready
for analysis (Notes 3 and 4).
Calculation
Calculate the concentration, D, of 40j( in drinking water in picocuries
per liter as follows:
K x 1.883
2.22
where:
K = concentration of potassium in mg/1 of sample,
1.883 = disintegration/minute for each mg potassium,
2.22 = conversion factor from disintegrations/minute to picocuries.
Notes:
1. This technique(1) is presented for those interested in calculating the
4^K in drinking water. All that is required is that total potassium
be determined in any manner available, and from this value, the radio-
active potassium value can be calculated.
2. The Osram potassium vapor-discharge lamp may also be used in the Perkin-
Elmer 303. In this case, the current should be 350 ma or the optimum
operating current.
a. Sodium may interfere if present at much higher levels than the
potassium. This effect can be compensated by approximately
matching the sodium content of the potassium standards with that
of the sample.
b. Potassium absorption is enhanced in the presence of Na, Li, and Cs,
especially in a high-temperature flame. This enhancement effect
of sodium can be eliminated by changing the burner height and the
type of flame used. The burner assembly is set approximately
0.05 cm below the optical light path so that the optical light
path is sliced at the bottom by the burner head. A fuel-rich
flame is used.
c. The 404.4 nm line may also be used. This line has a sensitivity
of 5 mg/1 for 1% absorption.
d. To cover the range of potassium values normally observed in
surface waters (0.1 to 20 mg/1), it is suggested that the burner
be rotated 75°.
3. Flame photometric or colorimetric methods^) may be used if atomic
absorption instruments are not available.
39
-------
4. The precision and accuracy of the technique was determined at the
Methods Development and Quality Assurance Research Laboratory (MDQARL).
Using distilled water samples at concentrations of 1.6 and 6.3 mg/1,
the standard deviations were +^0.2 and +_ 0.5, respectively. Recoveries
at these levels were 103% and 102%. With an optimum concentration range
between 0.1 and 2 mg/1 and with the use of a wavelength of 766.5 nm, the
sensitivity was 0.04 mg/1 and the detection limit was 0.005 mg/1.
References:
1. Methods for Chemical Analysis of Water and Wastes, p. 143. Methods
Development and Quality Assurance Research Laboratory, National Environ-
mental Research Center-Cincinnati, EPA-625/6-74-003 (1974).
2. Standard Methods for the Examination of Water and Waste Water, 13th ed.
pp. 283-285. American Public Health Association, Washington, D. C.
(1971).
40
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APPENDIX A
METHOD CAPABILITIES
METHOD CAPABILITIES*
Gross beta activity
Gross alpha activity
134
Cs
137
Cs
131
I
Radium-precipitation
276
Ra-Rn emanation
228
Ra
89
Sr
9°Sr
Tritium
Sample
Volume
100- ml
250 ml
500 ml
100 ml
250 ml
500 ml
1000 ml
1000 ml
2000 ml
2000 ml
1000 ml
2000 ml
1000 ml
1000 ml
4 ml
8 ml
Parameter
Counting
Efficiency %
39
41
31
34
32
40
70
40
42
33
30
23
2a MDL pCi/1
Instrument
Background
1.0 c/m
0.2
1.2
1.2
1.0
0.5
0.03
1.5
1.2
1.2
9.0
9.5
1000 min
count
1.2
0.5
0.3
0.5
0.2
0.1
0.2
0.2
0.1
0.04
0.01
0.06
0.3
0.1
150
70
60 min
count
4
1.8
1.0
1.8
0.8
0.5
0.6
0.5
0.3
0.15
0.04
0.3
0.9
0.5
500
300
With these parameters, the procedures in this manual can obtain the
corresponding minimum detection levels (MDL), assuming good chemical yield
recovery. The calculations were made with data from replicate testing of
these procedures. Variability in instrument background is a significant
factor in the determination of these values. The levels reported above can
be further reduced by the use of larger samples for analysis and better
instrument shielding.
41
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APPENDIX B
REAGENT PREPARATION
Distilled or deionized water should be used to prepare all reagents
requiring water as the solvent.
I. Carrier solutions - These solutions, prepared as the specific ion, are to
be filtered and standardized before use in chemical yield determinations.
Reagent blanks should be prepared in the appropriate geometry with
approximate final precipitate weight to ascertain instrument plus reagent
background.
Ba - 16 mg/ml. Dissolve 2.846 grams Bad .2H 0 in water, add 0.5 ml
16 N^ HNO,, and dilute to 100 ml with water.
Cs - 10 mg/ml. Dissolve 1.267 grams CsCl in water and dilute to 100 ml.
I~ - 20 mg/ml. Dissolve 2.616 grams KI in water, add 2 drops Na SO ,
and dilute to 100 ml. Store in dark flask.
10 - 10 mg/ml. Dissolve 1.685 grams KIO in water and dilute to 100 ml.
Store in dark flask.
Pb 15 mg/ml. Dissolve 2.397 grams Pb(NO ) in water, add 0.5 ml 16 N_
O £,
HNO , and dilute to 100 ml with water.
Pb++ - 1.5 mg/ml. Dilute 10.0 ml Pb(NO ) (15 mg/ml) to 100 ml with
O ^
water.
Sr - 20 mg/ml. Dissolve 4.831 grams Sr(NO ) in water and dilute to
O ^
100 ml.
Y - 18 mg/ml. Add 22.85 grams Y 0 to an Erlenmeyer flask containing
£ O
20 ml water. Heat to boiling and continue stirring
with a magnetic stirring hot plate while adding 16 IV
HNO in small amounts. Usually about 30 ml 16 N_
HNO, is necessary to dissolve the Y 0 . Small additions
J & *)
of water may be required to replace that lost by
evaporation. After total dissolution add 70 ml 16 N_
HNO and dilute to 1 liter with water.
Y+3 - 10 mg/ml. Dissolve 43.1 grams Y(N03)3-6H20 in 800 ml water, add
5 ml 6 IV HN0*' and dilute to 1 liter.
Sr++- Y+3 (mixed carrier) - (0.9 mg/ml Sr+2 and -0.9 mg/ml Y*3).
+3
Solution A - Dilute 10.0 ml yttrium carrier Y -(18 mg/ml) to 100-ml.
42
-------
Solution B - Dissolve 0.4348 grams Sr(NO ) in water and dilute to
100 ml. Combine Solutions A and B and label.
II. Acids and Inorganic Reagents
Ammonium acetate buffer, (CH COOH-CH COONH ) : pH 5.0. Mix 100 ml
1.5 N CH_COOH and 100 ml 3 M CH.COONH . .
— 3 — 3 4
Acetic acid, CH COOH, 17.4 N_: This is the concentrated (glacial) reagent;
sp. gr. 1.06, 99.5%.
Acetic acid, CH COOH, 1.5 N_: Dilute 86 ml glacial (17.4 N) acetic acid
O
to 800 ml with water and dilute to 1 liter.
Ammonium acetate, CH.COONH , 3 M: Dissolve 231 grams CH,COONH. in 600 ml
_ 5 _ 4 _ — J 4
water and dilute to 1 liter.
Ammonium hydroxide, NH OH, 15 N_: This is the concentrated reagent;
sp. gr. 0.9, 50%.
Ammonium hydroxide, 6 N: Add 400 ml 15 N NH OH to 400 ml water and
dilute to 1 liter.
Ammonium hydroxide, 2 N^: Dilute 100 ml 6 N_ NH OH to 300 ml with water.
Ammonium oxalate, (NH ) C 0 , 5%: Dissolve 25 grams (NH4)2C204 in water
and dilute to 500 ml.
Ammonium phosphomolybdate (prepared reagent) : Dissolve 100 grams of
molybdic acid (85% MoOs) in a mixture of 240 ml of water and 140 ml
15 N_ NH4OH. When solution is complete, filter and add 60 ml of 16 N_
HN03- Mix 400 ml of 16 N HN03 and 960 ml of water. Allow both solutions
to cool to room temperature. With constant stirring, add the ammonium
molybdate solution to the nitric acid solution. Allow to stand for
24 hours. Filter through Whatman #42 filter paper. Discard the
insoluble material.
Collect the filtrates in a 3-liter beaker and heat to 50° to 55°C.
Remove from heating unit. It is important that the solution not be
heated above 55°C to avoid contamination of the precipitate with molybdic
anhydride. Add 25 grams of NaH2P04 dissolved in 100 ml of water to the
ammonium molybdate solution. Stir occasionally for 15 minutes and allow
the precipitate to settle (approximately 30 minutes). Filter through
Whatman #42 filter paper. Wash the precipitate with 1% potassium
nitrate and finally with water. Dry the precipitate and paper at 100°C
for 3 to 4 hours. Transfer the (NH4)3(PMo^2°4o^ solid to a weighing
bottle, and store in a desiccator.
Ammonium sulfate, 200 mg/ml : Dissolve 20 grams (NH4)2S04 in a minimum
of water and dilute to 100 ml.
Ammonium sulfide, 2%: Dilute 10 ml (NH4)2S, (20-24%), to 100 ml with
water.
43
-------
Calcium chloride, 3 M:- Dissolve 330 grams CaCl2 in water and dilute to
1 liter.
Chloroplatinic acid, 0.1 M: Dissolve 51.8 grams H2PtCl6.6H20 in water
and dilute to 1 liter.
Citric acid, 1 Nl: Dissolve 19.2 grams CgHgOy in water and dilute to
100 ml.
Helium, gas
Hydrochloric acid, HC1, 12 N: This is the concentrated reagent;
sp. gr. 1.19, 37%.
Hydrochloric acid, 6 N: Add 500 ml 12 N HC1 to 400 ml water and dilute
to 1 liter.
Hydrochloric acid, 4 N: Add 333 ml 12 N HC1 to 500 ml water and dilute
to 1 liter.
Hydrochloric acid, 2 N: Dilute 333 ml 6 N HC1 to 1 liter with water.
Hydrochloric acid, 1 N: Dilute 250 ml 4 N HC1 to 1 liter with water.
Hydrofluoric acid, HF, 48% (~ 30 N): This is the concentrated reagent;
sp. gr. 1.15.
Iron chloride, 0.1 M: Dissolve 27 grams FeCl3.6H20 in water plus 2 ml
12 N_ HC1 and dilute to 1 liter.
Magnesium perchlorate, Mg(C104)2: reagent grade.
Nitric acid, HNO,, 16 N_: This is the concentrated reagent; sp. gr. 1.42,
~"~
70%.
Nitric acid, 6 N: Cautiously add 395 ml 16 N^ HN03 to 600 ml water and
dilute to 1 liter.
Nitric acid, 4 N: Cautiously add 250 ml 16 N HNC>3 to 700 ml water and
dilute to 1 liter.
Nitric acid, 1 N: Add 62 ml 16 N_ to HN03 to 900 ml water and dilute to
1 liter.
Nitric acid, 0.2 N_: Add 12.5 ml 16 N HN03 to 900 ml water and dilute
to 1 liter.
Oxalic acid, saturated: Dissolve 150 grains H2C2C>4 in 1 liter boiling
water.
Palladium chloride, 0.2 M: Dilute 118 ml 5% PdCl2 to 167 ml with 2 N HC1.
Phosphoric acid, H PO , 85% (44 N) : This is the concentrated reagent; -
O *r
sp. gr. 1.69.
44
-------
Silver nitrate, 0.1 M: Dissolve 17 grams AgN03 in water and dilute to
1 liter. Store in dark flask.
Sodium bisulfite, 1 M: Dissolve 5.2 grams NaHSOs in water and dilute to
50 ml. Prepare only in small quantities.
Sodium carbonate, 1.5 M: Dissolve 160 grams Na2CC>3 in 600 ml water and
dilute to 1 liter.
Sodium chromate, 0.5 M: Dissolve 171.1 grams Na2Cr04.10H20 in 400 ml
water and dilute to 1 liter.
Sodium hydroxide, 18 N: Dissolve 720 grams NaOH in 500 ml water and
dilute to 1 liter.
Sodium hydroxide, 10 N: Dissolve 400 grams NaOH in 500 ml water and
dilute to 1 liter.
Sodium hydroxide, 6 N: Dissolve 240 grams NaOH in 800 ml water and dilute
to 1 liter.
Sodium hydroxide, 1 N_: Dilute 100 ml 10 N_ NaOH to 1 liter with water.
Sodium hydroxide, 0.5 N: Dilute 50 ml 6 N NaOH to 600 ml with water.
Sodium nitrite, 1 M: Dissolve 69 grams NaN02 in water and dilute to
1 liter.
Sodium sulfite, 1 M: Dissolve 5 grams Na2S03 in 40 ml water. Prepare
fresh reagent every week.
Sulfuric acid, ^804, 36 14: This is the concentrated reagent; sp. gr.
1.84, 95-98%.
Sulfuric acid, 18 N^: Cautiously add, with stirring, 500 ml 36 N ^804 to
400 ml water and dilute to 1 liter.
Sulfuric acid, 12 14: Cautiously add, with stirring, 333 ml 36 I4_ H2S04
to 500 ml water and dilute to 1 liter.
Sulfuric acid, 9 N_: Cautiously add, with stirring, 250 ml 36 N_ ^804 to
600 ml water and dilute to 1 liter.
Sulfuric acid, 2 N_: Dilute 100 ml 12 N H2S04 to 600 ml with water.
Sulfuric acid, 0.1 J4_: Dilute 50 ml 2 N^ H2S04 to 1 liter with water.
Zinc, powder; Reagent grade.
45
-------
Ill . Organic reagents
Acetone, (CI^^CO, anhydrous
Ascarite, granular, 8 to 20 mesh
Carbon tetrachloride, CC1.
Diethyl ether, HO, anhydrous
EDTA reagent: Dissolve 20 grains NaOH in about 750 ml water, heat, and
slowly add 93 grams Na2CiQH1408N2-2H2° (disodium ethylenedinitriloacetate
dihydrate) while stirring. After the salt is in solution, filter through
coarse filter paper and dilute to 1 liter. This solution is - 0.25 M.
Ethanol, C2H5OH, 95%
Scintillation solution*: (If prepared in the presence of daylight or
fluorescent light, store in dark place 2 days before use.)
Dissolve 120 grams naphthalene, 0.05 grams 1,4-di (2-(5-phenyloxazolyl)
benzene) (POPOP) , and 4 grams 2, 5-diphenyloxazole (PPO) , in 1 liter of
p-dioxane. Store in an amber-colored bottle. Scintillation grade
reagents are recommended to ensure sample stability.
Tartaric acid, 50%: Dissolve 50 grams C^gOg in water and dilute to
100 ml.
IV. Indicators
Methyl red, 0.1%: Dissolve 0.1 grams methyl red indicator in 100 ml
ethanol.
Methyl orange, 0.1%: Dissolve 0.1 grams methyl orange indicator in
100 ml water.
* Commercially prepared scintillation solutions are available from several
supply houses, and can be substituted for this prepared stock solution.
46
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APPENDIX C
SOURCES OF SUPPLY
Glass-fiber filter paper:
Reeve Angel
9 Bridewell Place
Clifton, N. J.
Specification: 2.8 cm Grade 934 AH
Liquid scintillation vials:
Packard Instrument Co.
2200 Warrenville Rd.
Downers Grove, 111. 60515
Catalog #6001075 Polyethylene vial 20 ml, w/22 mm screw cap
Membrane filters:
Gelman Instrument Co.
Ann Arbor, Mich. 48106
Specification: Metricel, A-6, 47 mm, 0.45 y
Mylar film:
Cadillac Plastics
3818 Red Bank Rd.
Cincinnati, Ohio 45227
Specification: 0.0005 inch thick
Plastic rings and discs:
Control Molding Corporation
84 Granite Ave.
Staten Island, N. Y. 10303
Catalog #J-356 1-inch dia (natural color) nylon type 6/6
Polypropylene centrifuge tube:
Dynalab Corp.
P. 0. Box 112
Rochester, N. Y. 14601
Catalog #3103-0050 134 x 28.7 mm O.D. Closure #29C
Radon counter:
Randam Electronics,'Inc. Johnson Laboratories, Inc.
3091 Shadycrest Drive 3 Industry Lane
Cincinnati, Ohio 45236 Cockeysville, Md. 21030
Specifications: Bias network, detector circuits, 6 digit decade
counter. External high voltage supply and 2-inch
photomultiplier tubes.
47
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Radon emanation bubblers and associated glassware; These can be fabricated
by local glass companies with the specifications from Figures 3 and 4.
Scintillation cell:
Johnson Laboratories, Inc.
3 Industry Lane
Cockeysville, Md. 21030
Specifications: according to Figure 6.
Stainless-steel planchets:
Hruden Laboratory Products
P. 0. Box 1802
Ann Arbor, Mich. 48106
Catalog #75750 2 x 0.018 x 1/4 inches.
Teflon filter holder:
Atomic Products Corp.
Center Moriches, N. Y. 11934
48
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/4-75-008(Revised)
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
INTERIM RADIOCHEMICAL METHODOLOGY FOR DRINKING WATER
5. REPORT DATE
March 1976
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Herman L. Krieger
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Radiochemistry § Nuclear Engineering Branch
Environmental Monitoring and Support Laboratory
Cincinnati, Ohio 45268
10. PROGRAM ELEMENT NO. 2FH120
f1HA327 rRDAP 24-AAK: Task 005
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Research and Development and
Office of Radiation Programs
U.S. Environmental Protection Agency
Washington, D.C. 20460
13. TYPE OF REPORT AND PERIOD COVERED
In-house
14. SPONSORING AGENCY CODE
EPA-ORD
15. SUPPLEMENTARY NOTES
This report, a revision of EPA-600/4-75-008, September 1975, is an "interim manual"
until superseded.
16. ABSTRACT
A laboratory manual of radiochemical procedures has been compiled and edited for use
in the analysis of specific radionuclides in drinking water--nuclides for which the
U. S. Environmental Protection Agency has recommended maximum contaminant levels in
its Interim Drinking Water Regulations. In addition to gross activity analyses, the
procedures for 134/137Cs, 131:, 226/228Raj 89/90Sr, 3H and 40K were evaluated by
replicate testing to determine the method capabilities and minimum detection levels.
The results, which indicate that the sensitivity of these procedures is greater than
the present required limits, are given in the Appendix. Also appended is information
on reagent preparation and suggested sources for purchasing special equipment.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Chemical analysis
Potable water
Quality control
Radioactive contaminants
Radiochemistry
Maximum contaminant level
Minimum detection level
Procedures
Radiochemical analysis
13B
8. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
59
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
•fr U. S. GOVERNMENT PRINTING OFFICE: 1976-657-695/5'i20 Region No. 5-11
49
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