Uranium and thorium contents in bottled mineral waters

Thirty-four types of mineral waters bottled in Japan and 42 types of foreign mineral waters were analyzed especially for U and Th by ICP-MS. Japanese bottled waters exhibited rather low U concentrations below its detection limit of 2 ng/L up to 1.3 μ g/L. They are all below the Japanese water standard for U concentration. Foreign bottles showed a wide range of U contents up to 16 μ g/L and smaller Th contents up to 30 ng/L. Apparently, some foreign mineral waters contained a large amount of U exceeding the Japanese water standard. In spite of this, such mineral waters may be used as a readily-available uranium (and thorium) sample solution. Other various aquatic samples such as rainwater, lake water, river water, and tap water were also analyzed for U and Th. In Japan, U concentrations are of the order of several to several tens of ng/L for various samples in general, which is in accordance with those of bottled mineral waters. Uranium concentrations may be used as a key for environmental monitoring, as exemplified by water of Ashida River, Hiroshima Prefecture. (author)