STUDY OF THE VULNERABILITY TO CONTAMINATION OF A CRYSTALLINE AQUIFER SYSTEM IN THE MUNICIPALITY OF VÁRZEA ALEGRE-CE

Abstract

Throughout the history of humanity, water has been considered the basis for the establishment of civilizations in the territory, a source for the maintenance of life and raw material for various activities, a place of shelter and reproduction for various species of living beings, a reason for conflicts, a currency for use and exchange, among many other aspects. This paper deals with a case study that aims to analyze the vulnerability to contamination of a crystalline aquifer system in the municipality of Várzea Alegre, in the State of Ceará. Through a field visit, environmental impact assessment and application of the GOD methodology, the natural vulnerability of the aquifer was assessed based on the analysis of the area of the springs located in Sitio Riacho Verde, in the rural area of the Várzea Alegre. Regarding the uses of water from the springs, the ecological use for the maintenance of the species of the habitat present in the area was predominant. Regarding the environmental impacts present in the springs, the following were identified: absence or degradation of vegetation in the permanent preservation area (APP); deforestation and burning in the recharge areas of the springs; lack of protection and easy access to the springs; and changes in the color and odor of the water. The degree of preservation varied from poor to reasonable. Regarding vulnerability, the contamination of the aquifer in the spring area was insignificant or negligible, the potential for contaminant load was reduced or non-existent, and the risk of groundwater contamination was Grade I according to the Foster (2003) classification. In order to mitigate the impacts identified in the springs, it was recommended to clean and maintain the water outcrop areas, fence the entire radius of the APP and reforest it with native species; recover degraded areas in the aquifer system recharge area and control the use of the areas in order to avoid future impacts.