DETERMINATION OF CESIUM, RUBIDIUM AND SCANDIUM IN BIOLOGICAL AND ENVIRONMENTAL MATERIALS BY NEUTRON-ACTIVATION ANALYSIS

A simple method for the determination of cesium, rubidium and scandium in soil, vegetation and animal tissues by neutron activation analysis has been developed and evaluated. The methodology was designed to ena ble the comparison of fallout radiocesium from Chernobyl with stable e lements in radioecological studies. Sample materials are dried and hom ogenized, and aliquots are irradiated, in sealed polyethylene vials (c a. 0.5 cm3), for 7 hours at a reactor flux of ca. 3 . 10(12) n . cm-2. s-1. The activation products of interest have long half-lives, and ar e analyzed by high resolution gamma-spectrometry after a cooling time of at least 12 days. The practical lower limits for determination of C s, Rb and Sc are 3, 7 and 0.13 mug . kg-1 for soils and 10, 20, 0.4 mu g . kg-1 for biological materials, respectively. Measurement of scandi um levels in vegetation allows a straightforward correction to be made for soil contamination. Various applications to soil-grass-animal eco systems are described.