Estudo da qualidade da água para fins de consumo humano na localidade de Goba, Distrito de Namaacha, província de Maputo

Abstract

The town of Goba, located in the south of Maputo province, has the Umbelúzi River as its main source of water for human consumption. In addition to the Umbelúzi River, the communities have resorted to using groundwater from boreholes and artisanal wells, which are generally unprotected and of unknown quality. The general objective of this study is to assess the quality of water for human consumption from the main water supply sources in the town of Goba. To carry out the study, groundwater and surface water samples were collected during two campaigns, one in the dry season and the other in the rainy season, and physical-chemical and microbiological parameters were analysed. The results of this study showed that all samples presented at least one parameter above the maximum admissible values ​​(MAVs) established by Mozambican legislation for human consumption. The water wells in the Goba area suffer from salinization problems, due to their high levels and above the VMAs for electrical conductivity (EC), total dissolved solids (TDS), Cl - . On the other hand, the waters of the Umbelúzi River were shown to be unfit for consumption due to their parameters such as turbidity, total hardness, NO 3- , SO 42- and organic matter (OM) above the VMAs, requiring treatment. However, the Goba water treatment plant (ETAG) proved to be inefficient in removing contaminants from the water, with an increase in the levels of turbidity (1.37%), TDS (1.51%), Cl - (177.38%), NO 3- (32.75%) and total Fe (76.47%). Additionally, most samples have aggressiveness index (AI) values ​​between 10 and 12, being classified as moderately aggressive, and Langelier saturation index (LSI) values ​​lower than 0, which shows a corrosive tendency. In general, water from Goba’s water sources is undrinkable and unfit for human consumption, being severely affected by the natural dissolution of minerals from the area’s geological formations, as well as by runoff from agricultural land, rainwater, malfunctioning septic systems and open defecation. Based on the results, corrective and monitoring actions are necessary to resolve the discrepancies in the water’s sanitary conditions.(TRADUÇÃO NOSSA)