Recent environmental tritium levels in Japan Pt. 2

Tritium concentrations were analyzed for coastal seawater and lake water collected from various places in Japan. Low tritium concentrations were observed in coastal seawater of small islands which was attributed to short residence time of the groudwater in such small islands. Tritium concentrations in lake water showed significant variations. It was revealed that the size of the lake and its drainage area were the dominant factors controlling the tritium concentrations in lakes. (author)