Investigação hidrogeoquimica do processo de salinização aplicada ao sistema aquífero Dunas-Pecém, Ceará

Abstract

This work was carried out in the Pecém / Ceará district in the coastal region of the municipality of São Gonçalo do Amarante where a set of 36 tubular wells belonging to the Ceará Water Resources Management Company (COGERH) was installed; distributed in four batteries, for use in public supply. The studied area is inserted in the so-called Polígono das Secas, an area of the State that presents a rainfall regime marked by extreme irregularity of rains, both in time and space. The methodology to identify the characteristics of the studied aquifer under the aspect of recharge, salinization processes and water quality in the initial conditions of battery operation were: hydrochemical, isotopic measures and statistical techniques. The analysis of the results of the measurements made it possible to identify: i) characteristics of a coastal aquifer with marine contribution; ii) free aquifer conditions with fast recharge due to events of greater intensity; iii) effect of the evaporation process changing the salinity of the waters; iv) anthropic action in the aquifer; v) spatial variation revealing two groups of water and vi) quality of water for human consumption. The predominance of sodium chloride type water shows the contribution of sea water, through marine aerosols carried from the atmosphere during the rainy season. PH measurements reveal acidic waters and most hydrochemical data show waters chemically suitable for human consumption, although in some cases a slight effect of anthropic action was detected by the presence of ammonium and nitrate.