FRACIONAMENTO ISOTÓPICO DA ÁGUA DO SOLO DURANTE 0 PROCESSO DE EVAPORAÇÃO, EM PRESENÇA DE LENÇOL FREÁTICO

Abstract

This experiment was conducted with columns of soil, constitued by alluvion sediment keeping a phreatic watertable at a depth of 40 cm and constant water supply, and its objective was to check the water behaviour as to its deuterium and oxigem content when moving from the lower layers to the upper layers. and consequent loss to the atmosphere through evaporation. It was noted that the existing D and 18 O content in the water forming the phreativ watertable practically does not vary with this process. In addition to the observations on soil columns, soil water from the Brasilian northeastern region was collected and analysed. The phreatic watertable at the collecting site lay at a depth of about 40-50 cm. Preliminarily, it was noted that these results apparently indicate an excess evaporation, and are also consistent with those obtained by other investigators, who proposed the use of stable isotopes to study problems related to salinization of water in this region. The data now obtained are highly promising, but further studies on the region are required, taking up a determined region and correlating other data involved in the hydrological cicle.