Análise das concentrações de nitrato em águas superficiais e subterrâneas em área de atividade mineira no município de Caçapava do Sul – RS

Abstract

Nitrate is the most important inorganic contaminant in groundwater originating mainly from four sources: application of manure, fertilizers and inorganic with nitrogen; Soil cultivation; Human sewage; And naturally occurring atmospheric deposition. Due to anthropogenic actions its determination has increased in the last decades and the maximum values allowed for drinking water have been established for the regulators in the function of some diseases that are attributed to the consumption of water with the high concentration of nitrate, especially the Infant methemoglobinemia. Another source that may be associated with a nitrate contamination is an explosive substance that contains nitrogen in its composition and is widely used in mining for the process of dismantling rocks. Although the main sources of nitrate contamination are associated with animal excrement; Nitrogen fertilizers; Soil cultivation; And domestic effluents, a mining activity can also represent a source of contamination. This activity is present in the region, being responsible for about 80% of the limestone rock powder (it is not what is certain) produced in Rio Grande do Sul. This work presents as analyzes carried out in five points of the study area with the objective of To verify an influence of the mining activity on the nitrate concentrations of the waters of the region. Sampling consisted of the collection of two samples of well water and three samples of water from streams located in the municipality of Caçapava do Sul, RS. Physico-chemical analyzes were also carried out according to ABNT and Standart Methods for the Examination of Water and Wastewater, 21ª Ed (2005). The results were done based on resolutions nº 357/2005 and 396/2008 (CONAMA) and parameters for the water quality of the Ministry of Health resolution nº 2914/2011.