Water quality. Determination of radionuclides

A procedure is standardized for the routine determination of the gross beta activity in water. The sample in a platinum dish is evaporated to dryness on a water bath, and the residue is transferred into a pre-annealed and weighed crucible by means of cotton wetted with dilute HNO3, dried, annealed at 350 degC for 1 hour, and weighed. The annealing residue is ground in an agate mortar, formed into a uniform layer on a measuring dish, and stored in a dessicator prior to measurement. The beta activity is measured with a proportional, Geiger-Mueller or scintillation counter. A reference sample constituted by KCl with natural abundances of K isotopes and an empty dish (background) are measured likewise. (P.A.)