Determinação da qualidade da água de um rio tropical Sob a perspectiva do uso do solo e cobertura vegetal

Abstract

Water plays a fundamental role in the economic development of a nation and is essential to the life of all living beings. Anthropic activities, such as land use and occupation, cause changes in water quality values. In this study, we evaluated the spatial and seasonal variability of physical, chemical, biological and microbiological parameters, as well as possible relationships between land use patterns and vegetation cover in Rio dos Frades, south Bahia, northeast Brazil. The selected versions were compared with the standards established by Environment National Council - CONAMA Resolution No. 357/2005. It was observed that the parameters dissolved oxygen, pH and biochemical oxygen demand were in disagreement with values established by the legislation, downstream of the urban areas of Guaratinga and Itabela municipalities. With the aid allowed, if the selected parameters affect the distinct behavior for each dry and rainy period, in which the nitrogen series correlate with the rainy period while the turbidity is with the dry period. With the help of tools from a Geographic Information System (GIS), a basin delimitation and a supervised classification of land use and vegetation cover were performed, revealing a strong anthropic pressure suffered by the river, mainly caused by agriculture