ASTM D7939-15
Standard Test Method for Rapid Radiochemical Determination of Americium-241 in Water

Standard No.

ASTM D7939-15

Release Date

2015

Published By

American Society for Testing and Materials (ASTM)

Latest

ASTM D7939-15

Scope

5.1 This test method is considered a rapid method when compared to other classical methods for the determination of ²⁴¹Am in aqueous solutions. During the method validation of this method, a test batch of fourteen test samples plus quality control samples was chemically processed in ~7.5 hours. Additional time for counting the samples depends on the measurement quality objectives.

5.2 This test method is specific for Americium-241 (²⁴¹Am) in drinking water and other aqueous samples. However, if any isotopes of curium are present in the sample, they will be carried with americium during the analytical separation process and will be observed in the final alpha spectrum.

5.3 This test method is capable of achieving a required method uncertainty for ²⁴¹Am of 0.070 Bq/L at an analytical action level of 0.555 Bq/L. This test method is capable of achieving a required relative method uncertainty, φ_MR, 13 % above 0.555 Bq/L. This test method is capable of achieving a “required” minimum detectable concentration (MDC) of 0.055 Bq/L.

5.4 To attain these stated measurement quality objectives (MQOs), a sample volume of approximately 200 mL and count time of at least 1 to 3 hours are recommended. The sample turnaround time and throughput may vary based on additional project MQOs, the time for analysis of the final counting form, and initial sample volume. This test method should be validated before use following the protocols provided in Method Validation Guide for Qualifying Methods Used by Radiological Laboratories Participating in Incident Response Activities.4

5.5 This test method is intended to be used for water samples that are similar in composition to drinking water. This method was evaluated following the guidance presented for “Level E Method Validation: Adapted or Newly Developed Methods, Including Rapid Methods” in Method Validation Guide for Qualifying Methods Used by Radiological Laboratories Participating in Incident Response Activities and Chapter 6 of MARLAP, 2004.3 Multi-radionuclide analysis using sequential separation may be possible using this test method in conjunction with other rapid methods.

1.1 This test method is specifically for Americium-241 (²⁴¹Am) in drinking water and other aqueous samples. However, if any isotopes of curium are present in the sample, they will be carried with americium during the analytical separation process and will be observed in the final alpha spectrum. The presence of ²⁴³Am in the water sample will bias the results obtained by this test method.

1.2 This test method is applicable to samples in which radioactive contamination is from either known or unknown origins. If any filtration of the sample is performed before starting the analysis, those solids should be analyzed separately. The results from the analysis of these solids should be reported separately (as a suspended activity concentration for the water volume filtered) but identified with the filtrate results.

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ASTM D7939-15 Referenced Document

• ASTM C1163 Standard Test Method for Mounting Actinides for Alpha Spectrometry Using Neodymium Fluoride
• ASTM C1284 Standard Practice for Electrodeposition of the Actinides for Alpha Spectrometry
• ASTM D1129 Standard Terminology Relating to Water
• ASTM D1193 Standard Specification for Reagent Water
• ASTM D3370 Standard Practices for Sampling Water from Closed Conduits
• ASTM D4448 Standard Guide for Sampling Ground-Water Monitoring Wells
• ASTM D5847 Standard Practice for Writing Quality Control Specifications for Standard Test Methods for Water Analysis
• ASTM D6001 Standard Guide for Direct-Push Water Sampling for Geoenvironmental Investigations
• ASTM D7282 Standard Practice for Setup, Calibration, and Quality Control of Instruments Used for Radioactivity Measurements

ASTM D7939-15 history

• 2015 ASTM D7939-15 Standard Test Method for Rapid Radiochemical Determination of Americium-241 in Water