Vulnerabilidade aquífera e risco de contaminação da água subterrânea em meio urbano

Abstract

In urban areas, groundwater contamination is linked to high pression of urban use land; for this, applied restrictive politics of use land that promote groundwater conservation are necessary. The present article aims to evaluate the risk of water qua-lity contamination, developing a risk Index to Groundwater Contamination (IRCAS) applied to aquifers in urban environ-ment in the municipality of Fortaleza, Ceará, Brazil. The construction of the IRCAS was carried out from the GOD aquifer vulnerability methodology, adding the Environmental Sanitation Index (ISA), calculated by census sector based on 2010 census data of the Instituto Brasileiro de Geografia e Estatística (IBGE). The data were managed in the Information System Geographic (GIS), and validated from groundwater samples analyzed for nitrate (N-NO3-) concentrations. The IRCAS sho-wed that areas near to the coast presented a higher risk due to the high vulnerability of the aquifer represented by the Dunes Aquifer Systems, associated with areas of low sanitary quality. The main risk factor was the sanitary sewage. Highest concentrations of nitrate (24.4 – 40 mg/L) in 83% of these wells are associated to high risk zones.