Abstract
An attempt was made to apply Mn-impregnated acrylic fiber to the collection of small amounts of Raisotopes in natural waters. The Mn compound incorporated in this material was estimated to be KMn8O16⋅xH2O, which occurred naturally in Japan as cryptomelane. Collection by the Mn-impregnated acrylic fiber was effective in the pH region higher than 4 and the collecting efficiency was dependent on the temperature of water.
Radium concentrations observed at the upper stream of Tamagawa River tended to increase after rainfalls. The observed rises in Ra concentrations suggested that the rainfalls forced the stored water in the subsurface layer of the ground to discharge into the river water system.
