Análise da salinidade, nitrato, nitrito, amónia e os microrganismos biológicos das águas superficiais da bacia hidrográfica do rio Licuar e sua interferência nas condições sócio ambientais do distrito de Nicoadala, Zambézia.

Abstract

The general objective of this work was to analyze the salinity, nitrate, nitrite, ammonia and biological microorganisms of the surface waters of the Licuar river basin and their interference in the socio-environmental conditions of the district of Nicoadala, Zambézia. To carry out this work it was necessary to use several instruments such as GPS, Polyethylene bottles (500ml), Labels, Pen, Transparent tape, Hydrogen Peroxide, Toilet paper, Ice cubes, Coleman, Multiparameters, Secchi disk, Plate of Petrifilm and Greenhouse, for the collection and analysis of samples. Parameters such as temperature, salinity, pH and turbidity were analyzed in situ, that is, directly in the river. For biological microorganisms such as fecal coliforms, thermotolerants and chemicals such as nitrate, nitrite and ammonia, they were analyzed at the Águas da Região Centro (AdRC) laboratory in Quelimane. After analysis, the results indicated that, at all points there was no presence of fecal coliforms, for total coliforms, at point 1 it was 5 MPN/100ml, point 2 was 4 MPN/100ml, 12 MPN/100ml at the point 3 and in point 4 it was 10 MPN/100ml. For E. Coli, the results were, at point 1 it was 2 MPN/100ml, at point 2 it was 1 MPN/100ml, at point 3 it was 6 MPN/100ml and at point 4 it was 3 MPN/100ml. For the data immediately measured, such as temperature, the following results were indicated at points 1, 2, 3 and 4: 24.4 ºC, 25.8 ºC, 23.7 ºC and 27.2 ºC respectively. The salinity indicated at point 1, 2.1‰, at point 2 it was 0.09‰ and 0‰ at points 3 and 4. Dissolved oxygen at point 1 was 180.1, at point 2 it was 186.3, at point 3 it was 150.2 and at point 4 it was 183.7% saturation. For pH and transparency, at point 1 it was 7.22 and 70 cm, at point 2 it was 6.67 and 25 cm, at point 3 it was 8.21 and 65 cm and at point 4 8, 61 and 65 cm respectively. For nitrate, nitrite and ammonium, at point 1 it was 2.8 mg/l, 0.027 mg/l and 0 mg/l, at point 2 it was 2 mg/l, 0.053 mg/l and 0.01 mg/l, at point 3 was 2.7 mg/l, 0.049 mg/l and 0.04 mg/l and in point 4 it was 1.7 mg/l, 0.064 mg/l and 0.22 mg/l respectively. In summary, it is concluded that the levels of total coliforms and Escherichia coli were above the maximum value recommended by the WHO and there was no presence of fecal coliforms. The water in the Licuar river basin has very low salinity, making the water completely fresh. Parameters such as nitrate, nitrite and ammonium were within water potability standards, as they were below the maximum limit recommended by the WHO.