Estado trófico da Bacia Hidrográfica dos afluentes mineiros do Rio Verde Grande

Abstract

This study aimed to assess the quality of the water in relation to the level of trophy, as well as whether the spatio-temporal variation influences the states of trophy in which the affluent miners of the Rio Verde Grande Basin fall. In this study, data from 20 monitoring stations, located in the Juramento, Mosquito, Gorutuba, Serra Branca, Ribeira do Ouro, Caititu, Verde Grande, Arapoim and Rio dos Vieiras rivers were compiled. The Trophic State Index (TSI), a calculation tool that uses the variables of the parameters chlorophyll-a and total phosphorus, was used to determine the evolution of water quality regarding nutrient enrichment and its effect related to the excessive growth of algae. Sampling was carried out in the months of March, June, September and December 2018 by the Instituto Mineiro de Gestão das Águas. Through the classification of the TSI, it is concluded that the watersheds of the basin present different degrees of trophy throughout the year, and monitoring stations of the same watercourse do not present similarity in trophic classification. In addition, there is no direct influence of the temporal variations in the TSI values. The rivers Mosquito, Gorutuba (station VG009), Verde Grande (stations SFJ16, VG001, VG004 and SFH21) and Rio dos Vieiras had the worst trophic indices in the Rio Verde Grande Basin, indicating that the basin is significantly impacted by the release of domestic and industrial effluents such as dairy, slaughterhouse and textile industries.