Estudo da contaminação por Nitrato e Coliformes nas águas subterrâneas na sede de Mucupia, distrito de Inhassunge

Abstract

The Mucupia Administrative Post, capital of the Inhassunge District, has a local population that has only one type of supply system, which is through tubular wells and shallow wells, without sewage collection system, using the in situ sanitation system. The present work consists of a study of the evaluation of the level of contamination by nitrate and coliforms in groundwater by in situ sanitation system in the region. 17 wells (9 tubular and 8 cacimbas) were registered in the area, but water samples were collected in 10 wells (6 tubular and 4 shallow) for the analysis of contamination parameters. The concentrations of nitrate and ammonium were determined by a portable photometer, for bacteriological analysis the bacterial counting method was used through the use of Petrifilm plates. The highest nitrate concentration was 12 mg / L, where 60% of the waters of the wells sampled showed levels of evidence of nitrate contamination. The bacteriological analyzes carried out in the wells indicated higher contamination by fecal coliforms in the shallow wells (55%) in relation to the tubular wells (45%), in relation to contamination by E. coli were found in high numbers in the shallow wells (81%) in relation to tubular wells (19%). The results of ammonium, pH and temperature did not reach maximum values established by MISAU (2004). It was concluded that the wells did not present high concentrations of nitrate, the shallow wells were the most affected by the presence of bacteria of the coliform group, therefore, to minimize the contamination of the groundwater, it is recommended to establish construction of water exploration wells, as well as cesspits and latrines, the implementation of alternative sewage treatment systems and it is also recommended to guide the populations in the region to disinfect the water.