Pages: 9
Replaces: ASTM D4785- 08(2013)e1
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 limits for drinking water. With suitable counting techniques, sample size, and counting time, a detection limit of less than 0.037 Bq/L (1 pCi/L) is attainable by gamma-ray spectrometry.
This test method is intended for 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. The test method was tested according to Practice D2777 using only ¹³¹I. The user of this test method is responsible for determining applicability, bias, and precision for the measurement of other iodine radioisotopes.