GEOCHEMICAL INVESTIGATIONS OF SALINIZED GROUNDWATER USING ENVIRONMENTAL ISOTOPES

Abstract

Geochemical investigations of salinized groundwater in Motooka area, west of Fukuoka City, Japan were carried out. The measured tritium concentrations in the shallow groundwater system are higher than those of the deeper groundwater system. From the results of hydrogen-oxygen isotope ratio plotting on the mixing line of meteoric water and seawater, it was inferred that the deeper groundwater is affected by seawater. ¹⁴C isotope dating of a shell that was collected at the depth of approximately 2m from the core samples of B2 indicated the age of about 2000 years. Accordingly, the salinized groundwater in this area was assumed to be originally below the sea bottom. Further, it was found that the geochemical properties of salinized groundwater should be utilized as the index of the environmental isotopes as well as characterization of the water quality using Piper diagram.