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CONTRIBUIÇÃO AO ESTUDO ISOTÓPICO E QUÍMICO DOS AQÜÍFEROS DA REGIÃO DE FRECHEIRINHA-CEARÁ

1982; Sociedade Brasileira de Geologia; Volume: 12; Issue: 4 Linguagem: Inglês

10.25249/0375-7536.1982124546552

2177-4382

HAROLDO BARBOSA DE SIQUEIRA, JOAQUIM RAUL TORQUATO, MARLÚCIA FREITAS SANTIAGO, HORST FRISCHKORN,

Groundwater and Isotope Geochemistry

The isotopic and chemical characteristics of the aquifers in the area o f Frecheirinha (State of Ceara) have been analyzed. In an area of 3,000 square kilometers three aquifers have been identified: one in the east with an age of about 5,000 years; one in the West of 2,500 years; and a central one of about 1,000 years. Except for the region east of Aprazível, the aquifers are of the unconfined type with decreasing age during the rainy season. Oxygen-18 measurements show that during the rainy season the piezometric level rises until reaching the surface. Thus the flow-water is a mixture of rainwater with stored under-groundwater. During the dry season flow-water is exclusively phreatic. Chemical analysis shows all waters (except for samples 1, 2 and 3) are potable. During the rainy season, however, the chemical composition is strongly affected by a washout of deposited aerosols and fertilizers in the Serra da Ibiapaba causing a substantial increase in sodium, chloride and sulfates.