Impacts of the Urbanization Process on Water Quality of Brazilian Savanna Rivers: The Case of Preto River in Formosa, Goiás State, Brazil

The release of domestic sewage in water resources is a practical feature of the urbanization process, and this action causes changes that may impair the environmental balance and the water quality for several uses. The aim of this study was to evaluate the influence of urbanization on the surface water quality of the Preto River throughout the town of Formosa, Goiás, Brazil. Samples were collected at five points along the river, spatially distributed from one side to the other of the town of Formosa, from May to October of 2012. Data were subjected to descriptive statistics, as well as variance and cluster analysis. Point P2, the first point after the city, showed the worst water quality indicators, mainly with respect to the total and fecal coliform parameters, as well as nitrate concentrations. These results may be related to the fact that this point is located on the outskirts of the town, an area under urbanization and with problems of sanitation, including absence of sewage collection and treatment. The data observed in this monitoring present a public health concern because the water body is used for bathing, mainly in parts of Feia Lagoon. The excess of nutrients is a strong indicator of water eutrophication and should alert decision-makers to the need for preservation policies.