武蔵野台地の地下水中の^<234>U/^<238>U比

概要

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Concentrations of ^<234>U and ^<238>U in the groundwater samples from Musashino-daichi, western Tokyo have been measured by alpha-spectrometry. Observed range of ^<234>U and ^<238>U concentrations were about 0.2-3.5 and 0.3-9.3 dpm/100l, respectively, with the ^<234>U/ ^<238>U activity ratios of 1.4-5.0 The presence of excess ^<234>U, together with the observed linear correlation with ^<238>U concentrations, indicates both excess ^<234>U and ^<238>U have been supplied by source materials which are uniform with respect to the ability of supplying recoilgenic ^<234>U and ^<238>U into the groundwaters. High tritium concentrations in many of the samples (Tanaka, 1983) indicate the groundwater samples were composed of two distinct water components: one with fairly long age of contact with U containing minerals (orders of 1000 yrs or more) and one with fairly short tritium age (less than about 30 yrs).
日本地球化学会の論文
1983-12-25