Estudo comparativo de métodos analíticos utilizados na determinação de nitrato em águas subterrâneas

Abstract

With the strong surface water resources shortage, the exploitation of underground water resources is increasing. With this, the occurrence of contamination of these Springs is increasingly noticeable and disturbing, because it brings in serious health risks who depends on this type of source for consumption. Considered as inorganic contaminant more common in groundwater, the nitrate ion due to your high stability, solubility and mobility in water is highly recurrent in groundwater resources and is one of the parameters of water potability prepared by the Ordinance of the Ministry of health MS Nº 2914/2011 and CONAMA resolution N° 396/2008. Determination of nitrate in groundwater is given with the use of various analytical techniques, being the most used spectrophotometry. This technique adds number analytical methods as the method of reducing cadmium-copper column and what uses the salt sodium salicylate. Aimed to compare such methods to verify the sensitivity of each method. With the analysis of a small sample of well water, highly discrepant results were obtained using the methods already mentioned. The discrepancy observed is supposedly justified by the limitation of the analytical equipment, checking on erroneous data in the quantification of the analyte in the sample. From the method of reducing cadmium column, examine samples with nitrate content above the maximum value allowed by the order of the provisions of Ministry of health MS No. 2914/2011 and CONAMA resolution N° 396/2008, precludes the use of this water, because otherwise, risks of the development of diseases such as cancer and metahemoglobinemia. From the data presented may still conclude the greater sensitivity of the method advocated by the brazilian legislation for the determination of water quality, when compared to the sodium salicylate method.