Efeitos do uso e ocupação do solo nas águas subterrâneas a sudeste do município de Fortaleza – Ceará

Abstract

We attempted this work to investigate the relationship between the use and occupation, with respect to aspects of occupancy rate, soil sealing and agricultural activities, and the characterization of the local sewage at concentrations of nitrogenous compounds in groundwater in four continuous subbasins, located in a peripheral area in the southeast of the city of Fortaleza - CE. Was held image classification object-oriented in order to extract the occupancy rates for each census tract, such procedure was performed with the help of Geographic Information System - GIS tool also used to assess the health situation in the area study was based on data from the 2000 census and 2010 the Brazilian Institute of Geography and Statistics - IBGE. Wells registration update was performed, consisting 64 wells, of which 24 samples were collected for Total Solids measures Dissolved - STD and pH, and conducting Ammonia analysis (N-NH 3 +), nitrite (NO2) and nitrate ( NO3-N). It was observed waterproofing levels above allow for law beyond precarious situation of sanitation, which has as main feature the use of septic tanks and rudimentary. It was noticed that the highest occupancy rates are related to the precarious sanitary conditions, and the sub-standard settlements have the most unsanitary conditions. Such a condition attributed to high occupancy rates and the highest densities of septic and rudimentary tanks, acting as areas nitrate contamination sources, featuring a kind of diffuse contamination that occurs from the effluent entering the sub-saturated layer of the unconfined aquifer allowing oxidation which results in consequent nitrate contamination, especially in areas interfluvial higher water table.