The use of radioactive tracers in sedimentation research

Abstract

The transport of sediment was investigated using radioisotopes to ‘tag’ individual sand particles. Scandium 46, a γ emitter with an 85-day half-life, was employed. The techniques developed for tagging sand particles and the resistance of these tagged sand grains to abrasion and leaching are presented. The method allowed the experimenter to vary the specific activity of the sand particle as desired. Individual sand particles, about 0.4 to 0.5 mm in diameter, have been prepared with an activity of 2 milliroentgens per hour, or more, with no changes in the physical properties of the sand. The attenuation of the Sc46 emissions have been evaluated differentially and integrally with a γ-scintillation spectrometer. The use of a γ-scintillation technique has proved very satisfactory for laboratory studies, including transport studies in flumes. The preliminary field studies indicate that the prepared sand particles perform satisfactorily as tracers for sediment movement.