RN-222 CONCENTRATIONS AND VARIATIONS IN UNCONFINED GROUNDWATER

Vertical distributions of concentration increase in unconfined groundwater were clearly obtained in summer rather than in winter due to the stability of water density, although the spatial distributions of concentration were observed in a restricted area. The continuous extraction of groundwater causes pronounced increase of the concentration, thus it was necessary to drain more than 1 m**3 of water to get the representative concentration, which coincides with that of deep groundwater of the same geology. The concentration diluted by the precipitation recovers to the former level within a week. Refs.