THORIUM, URANIUM AND PLUTONIUM ISOTOPES IN THE ARKANSAS RIVER

Radiochemical measurements of the concentrations of thorium, uranium and plutonium isotopes were carried out for the samples of Arkansas River collected at six locations in the states of Colorado and Oklahoma. The uranium to thorium ratios in the river samples were found to be highly variable and generally much greater than the ratios found in soils and in rainwater. An attempt has been made to determine the apparent230Th ages (or the times which elapsed since the last major disruption of the radioactive equilibria) from the observed230Th/232Th and234U/232Th ratios in the water samples.