title: Uranium isotopes in well water samples as drinking sources in some settlements around the Semipalatinsk Nuclear Test Site, Kazakhstan.
abstract: Radiochemical results of U isotopes (234U,235U and238U) and their activity ratios are reported for well waters as local sources of drinking waters collected from the ten settlements around the Semipalatinsk Nuclear Test Site (SNTS), Kazakhstan. The results show that238U varies widely from 3.6 to 356 mBq/L (0.3-28.7 μg/L), with a factor of about 100. The238U concentrations in some water samples from Dolon, Tailan, Sarzhal and Karaul settlements are comparable to or higher than the World Health Organization's restrictive proposed guideline of 15 μg (U)/L. The234U/238U activity ratios in the measured water samples are higher than 1, and vary between 1.1 and 7.9, being mostly from 1.5 to 3. The measured235U/238U activity ratios are around 0.046, indicating that U in these well waters is of natural origin. It is probable that the elevated concentration of238U found in some settlements around the SNTS is not due to the close-in fallout from nuclear explosions at the SNTS, but rather to the intensive weathering of rocks including U there. The calculated effective doses to adults resulting from consumption of the investigated waters are in the range 1.0-18.7 μSv/y. Those doses are lower than WHO and IAEA reference value (100 μSv/y) for drinking water.
authors.affiliation: Low Level Radioactivity Laboratory, K-INET, Kanazawa University, Wake, Nomi-shi, Ishikawa 923-1224 Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Low Level Radioactivity Laboratory, K-INET, Kanazawa University, Wake, Nomi-shi, Ishikawa 923-1224 Japan.
authors.forename: Junpei
authors.initials: J
authors.lastname: Tomita
authors.affiliation: Faculty of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526 Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Sakaguchi
authors.affiliation: Institute of Environmental Sciences, Rokkasho-mura, Aomori, 039-3212 Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Ohtsuka
authors.affiliation: International Radiation Information Center, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, 734-5883 Japan.
authors.forename: Masaharu
authors.initials: M
authors.lastname: Hoshi
authors.affiliation: Kazakh Scientific Research Institute for Radiation Medicine and Ecology, Semipalatinsk, The Kazakhstan Republic.
authors.forename: Kazbek N
authors.initials: KN
authors.lastname: Apsalikov
keywords: Annual effective dose; Kazakhstan; Semipalatinsk nuclear test site; Uranium isotopes; Well waters