ASTM D4785 - 08(2013)e1

    Standard Test Method for Low-Level Analysis of Iodine Radioisotopes in Water

    Active Standard ASTM D4785 | Developed by Subcommittee: D19.04

    Book of Standards Volume: 11.02


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    Significance and Use

    5.1 This test method was developed for measuring low levels of radioactive iodine in water. The results of the test may be used to determine if the concentration of several radioisotopes of iodine 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. This method was tested for 131I . Other iodine radioisotopes should behave in an identical manner in this procedure. However, other iodine radioisotopes have not been tested according to Practice D2777. The user of this method is responsible for determining applicability, bias, and precision for the measurement of other iodine radioisotopes using this method.

    5.2 This procedure addresses the analysis of iodine radioisotopes with half-lives greater than 2 hours, which include  121I,  123I,  124I,  125I,  126I,  129I,  130I,  131I,  132I,   133I, and  135I.

    1. Scope

    1.1 This test method covers the quantification of low levels of radioactive iodine 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 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 8.17, 8.18, 8.19, Section 9, and 13.2.11.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D1129 Terminology Relating to Water

    D1193 Specification for Reagent Water

    D2777 Practice for Determination of Precision and Bias of Applicable Test Methods of Committee D19 on Water

    D3370 Practices for Sampling Water from Closed Conduits

    D3648 Practices for the Measurement of Radioactivity

    D3649 Practice for High-Resolution Gamma-Ray Spectrometry of Water

    D3856 Guide for Management Systems in Laboratories Engaged in Analysis of Water

    D5847 Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis


    ICS Code

    ICS Number Code 13.060.50 (Examination of water for chemical substances)

    UNSPSC Code

    UNSPSC Code 41113405(Gamma counters)


    DOI: 10.1520/D4785

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