ASTM D4785-00a

Standard Test Method for Low-Level Iodine-131 in Water

SIGNIFICANCE AND USE
This test method was developed for measuring low levels of iodine-131 in water. The results of the test may be used to determine if the concentration of iodine-131 in the sample exceeds the regulatory statutes for drinking water. With a suitable counting technique, sample size, and counting time, a detection limit of less than 0.037 Bq/L (1 pCi/L) is attainable by gamma-ray spectroscopy.
SCOPE
1.1 This test method covers the quantification of low levels of iodine-131 in water by means of chemical separation and counting with a high-resolution gamma ray detector. Iodine is chemically separated from a 4-L water sample using ion exchange and solvent extraction and is then precipitated as cuprous iodide for counting.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information purposes only.
1.3  This standard does not purport to address all of the safety problems, 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 Note 2, Note 3, Note 8, and Section 9.

General Information

• Status: Historical
• Publication Date: 09-Jul-2000
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: D19 - Water
• Drafting Committee: D19.04 - Methods of Radiochemical Analysis

Relations

• Replaced By: ASTM D4785-08 - Standard Test Method for Low-Level Analysis of Iodine Radioisotopes in Water
• Effective Date: 01-Apr-2008

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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:D4785–00a
Standard Test Method for
1
Low-Level Iodine-131 in Water
This standard is issued under the fixed designation D4785; 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 the radioactive iodide. Hydroxylamine hydrochloride and so-
dium bisulfite are added to convert all the iodine to iodide
1.1 This test method covers the quantification of low levels
which is then removed by anion exchange. Subsequent elution
of iodine-131 in water by means of chemical separation and
of the iodide followed by oxidation-reduction yields elemental
counting with a high-resolution gamma ray detector. Iodine is
iodine. The elemental iodine is purified by solvent extraction,
chemically separated from a 4-L water sample using ion
reduced to iodide, and precipitated as cuprous iodide. The
exchange and solvent extraction and is then precipitated as
chemical yield is determined from the recovery of the iodide
cuprous iodide for counting.
carrier.
1.2 The values stated in SI units are to be regarded as
standard. The values given in parentheses are provided for
5. Significance and Use
information purposes only.
5.1 This test method was developed for measuring low
1.3 This standard does not purport to address all of the
levels of iodine-131 in water. The results of the test may be
safety concerns, if any, associated with its use. It is the
used to determine if the concentration of iodine-131 in the
responsibility of the user of this standard to establish appro-
sampleexceedstheregulatorystatutesfordrinkingwater.With
priate safety and health practices and determine the applica-
a suitable counting technique, sample size, and counting time,
bility of regulatory limitations prior to use. For specific hazard
adetectionlimitoflessthan0.037Bq/L(1pCi/L)isattainable
statements, see Note 2, Note 3, Note 8, and Section 9.
by gamma-ray spectroscopy.
2. Referenced Documents
6. Interferences
2.1 ASTM Standards:
2 6.1 Stable iodine in the sample will interfere with the
D1129 Terminology Relating to Water
2 chemical yield determination. One milligram of iodine would
D1193 Specification for Reagent Water
produce a bias of about −4%.
D2777 Practice for Determination of Precision and Bias of
2
Applicable Test Methods of Committee D-19 on Water
7. Apparatus
D3370 Practices for Sampling Water from Closed Con-
2 7.1 Analytical Balance, readable to 0.1 mg.
duits
1
3 7.2 Flexible Polyvinyl Chloride (PVC) Tubing,6.35mm( ⁄4
D3648 Practices for Measurement of Radioactivity
in.) outside diameter, 1-m length.
D3649 Practice for High-Resolution Gamma-Ray Spec-
3 7.3 Gamma-Ray Spectrometry System—high resolution us-
trometry of Water
ing a high-purity germanium or lithium-drifted germanium
3. Terminology detector (see Practice D3649).
7.4 Glass Fiber Filter Paper, 11.5-cm diameter.
3.1 Definitions—For definitions of terms used in this test
7.5 Ion Exchange Column, glass tube, 35 6 2-mm inside
method, refer to Terminology D1129.
diameter, 150-mm length, fitted with No. 8 one-hole stoppers
4. Summary of Test Method and perforated disk.
7.6 Membrane Filters, 0.4 or 0.45-µm pore size, 25-mm
4.1 Sodium iodide is added as a carrier prior to performing
diameter, with suitable filter holder and vacuum filter flask.
any chemical separations. The samples undergo an oxidation-
7.7 Peristaltic Tubing Pump, variable speed, fitted with
reduction process to ensure exchange between the carrier and
vinyl or silicone tubing.
7.8 pH Meter.
1
This test method is under the jurisdiction ofASTM Committee D19 on Water
7.9 Sintered Glass Filter, Buchner funnel, 150-mL size,
andisthedirectresponsibilityofSubcommitteeD19.04onMethodsofRadiochemi-
medium or coarse porosity with suitable one-hole stopper and
cal Analysis.
vacuum filter flask.
Current edition approved July 10, 2000. Published October 2000. Originally
7.10 Vacuum Desiccator.
published as D4785–88. Last previous edition D 4785–00.
2
Annual Book of ASTM Standards, Vol 11.01.
3
Annual Book of ASTM Standards, Vol 11.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D4785–00a
7.11 Vortex Mixer. 8.15 Sodium Bisulfite Solution (2 M)—Dissolve 104.06 g
of NaHSO in approximately 300 mL of water in a 500-mL
3
volumetric flask and dilute to volume.
8. Reagents and Materials
8.16 Sodium Chloride Solution (1 M)—Dissolve 58.45 g of
8.1 Purity of Reagents—Reagent grade chemicals shall be
NaCl in approximately 500 mL of water in a 1000 mL
used in all tests. Unless otherwise indicated, it is intended that
v
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