Direct measurement of U-238 in natural waters by ICP-MS

The fundamental experiments and analysis of environmental samples were studied in this work by direct measurement of U-238 in natural water using ICP-MS. The results proved that if a sample was collected and immediately filtered on site and adjusted to about 2% nitric acid, the value was not changed for six days. However, the effects of the large concentration of matrix elements in the sample must be considered. This direct measurement method of U-238 using ICP-MS can determine many samples in a short time with high sensitivity. This method can use in case of necessity. Three kinds of inland water samples were collected in Tokai-mura (Ibaraki), Kumagaya-shi (Saitama) and Rokkasho-mura (Aomori). The concentrations of U-238 in the above samples were from several to 160 ppt. However, U-238 of inland water of Sinkiang in China was from 100 to 53100 ppt, very higher value than Japan. (S.Y.)