ASTM D6239-03

Standard Test Method for Uranium in Drinking Water by High-Resolution Alpha-Liquid-Scintillation Spectrometry

SIGNIFICANCE AND USE
This test method is a fast, cost-effective method that can yield limited isotopic activity levels for  238U and  234U, as well as total uranium activity. Although  232U is incorporated as a tracer, uranium recoveries for this test measured during the developmental work on this test method were usually between 95 and 105%.
The high-resolution alpha-liquid-scintillation spectrometer offers a constant 99.6 ± 0.1 % counting efficiency and instrument backgrounds as low as 0.001 counts per minute (cpm) over a 4 to 7 MeV energy range according to McDowell and McDowell (2). Count rates for extractive scintillator blanks and reagent blanks usually range from 0.01 cpm to 0.1 cpm.
SCOPE
1.1 This test method covers determining the total soluble uranium activity in drinking water in the range of 0.037 Bq/L (1 pCi/L) or greater by selective solvent extraction and high-resolution alpha-liquid-scintillation spectrometry. The energy resolution obtainable with this technique also allows estimation of the  238U to 234U activity ratio.
1.2 This test method was tested successfully with reagent water and drinking water. It is the user's responsibility to ensure the validity of this test method for waters of untested matrices.
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see Section 9.

General Information

• Status: Historical
• Publication Date: 09-Jun-2003
• Technical Committee: D19 - Water
• Drafting Committee: D19.04 - Methods of Radiochemical Analysis

Relations

• Replaces: ASTM D6239-02 - Standard Test Method for Uranium in Drinking Water by High-Resolution Alpha-Liquid-Scintillation Spectrometry
• Effective Date: 10-Jun-2003
• Replaced By: ASTM D6239-03e1 - Standard Test Method for Uranium in Drinking Water by High-Resolution Alpha-Liquid-Scintillation Spectrometry
• Effective Date: 10-Jun-2003

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D6239–03
Standard Test Method for
Uranium in Drinking Water by High-Resolution Alpha-Liquid-
1
Scintillation Spectrometry
This standard is issued under the fixed designation D6239; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.1 Fordefinitionsoftermsusedinthistestmethod,refer
to Terminology D1129. For terms not included in this refer-
1.1 This test method covers determining the total soluble
3
ence, refer to other published glossaries (1)
uranium activity in drinking water in the range of 0.037 Bq/L
(1 pCi/L) or greater by selective solvent extraction and
4. Summary of Test Method
high-resolutionalpha-liquid-scintillationspectrometry.Theen-
4.1 This test method is based on solvent extraction technol-
ergy resolution obtainable with this technique also allows
238 234 ogy to isolate and concentrate uranium in drinking water for
estimation of the Uto U activity ratio.
counting via a high-resolution alpha-liquid-scintillation spec-
1.2 This test method was tested successfully with reagent
trometer.
water and drinking water. It is the user’s responsibility to
4.2 To determine total uranium, as well as limited isotopic
ensure the validity of this test method for waters of untested
238 234
uranium ( U and U) by activity in drinking water, a
matrices.
232
200–mL acidified water sample is first spiked with Uasan
1.3 The values stated in SI units are to be regarded as
isotopic tracer, boiled briefly to remove radon, and evaporated
standard. The values given in parentheses are for information
until less than 50 mL remain. The solution is then made
only.
approximately 0.01 M in diethylenetriaminepentaacetic acid
1.4 This standard does not purport to address all of the
(DTPA) and the pH is adjusted to between 2.5 and 3.0. The
safety concerns, if any, associated with its use. It is the
sample is transferred to a separatory funnel and equilibrated
responsibility of the user of this standard to establish appro-
with 1.50 mL of an extractive scintillator containing a dialkyl
priate safety and health practices and determine the applica-
phosphoric acid extracting agent. Under these conditions only
bility of regulatory limitations prior to use. For specific hazard
uraniumisquantitativelytransferredtotheorganicphasewhile
statements, see Section 9.
the extraction of undesired ions is masked by the presence of
2. Referenced Documents DTPA. Following phase separation, 1.00 mL of the organic
2
phase is sparged with dry argon gas to remove oxygen, a
2.1 ASTM Standards:
chemical quench agent, and counted on a high-resolution
D1129 Terminology Relating to Water
alpha-liquid-scintillation spectrometer and multichannel ana-
D1193 Specifications for Reagent Water
lyzer (MCA).
D2777 Practice for Determination of Precision and Bias of
4.3 The alpha spectrum of a sample that contains natural
Applicable Methods of Committee D19 on Water
232
uranium and that is analyzed with an internal U tracer will
D3370 PracticesforSamplingWaterfromClosedConduits
appear similar to the spectrum in Fig. 1. An approximate
D3648 Practices for the Measurement of Radioactivity
238
resolution of 250 keV FWHM for U (4.2 MeV) allows
238 234 232
3. Terminology
resolution and analysis of the U, U, and U energy
spectrum peaks when their activities are of the same order of
3.1 Definitions:
235
magnitude.Resolutionofthe U(4.4MeV)alphapeakisnot
possible, but its activity, which accounts for approximately
1
This test method is under the jurisdiction ofASTM Committee D19 on Water 2.2% of the total natural uranium activity, is included in the
238 234
andisthedirectresponsibilityofSubcommitteeD19.04onMethodsofRadiochemi-
totaluraniumactivitycalculatedwhenthe Uand Upeaks
cal Analysis. 238 234
are in the region of interest (ROI). When the U and U
Current edition approved June 10, 2003. Published August 2003. Originally
235
peaks are integrated separately, a portion of the U activity
approved in 1998. Last previous edition approved in 2002 as D 6239–02.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on The boldface numbers in parenthesis refer to the list of references at the end of
the ASTM website. the text.
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D6239–03
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solution. Sulfate ion (SO ) did not interfere with the extrac-
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tionofuraniumat
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