WATER QUALITY AND LAND COVER CHANGE IN THE PAST 25 YEARS IN MINAS GERAIS, BRAZIL

Código

XXV-SBRH0314

Autores

Danieli Mara Ferreira, PAULO RÓGENES MONTEIRO PONTES, Rosane Barbosa Lopes Cavalcante, Raquel Fernandes Mendonça

Tema

STE17 - METODOLOGIAS DE AVALIAÇÃO DA QUALIDADE AMBIENTAL EM ÁGUAS SUPERFICIAIS

Resumo

The analysis of water quality data in rivers have an essential role in understanding and managing environmental health within watersheds. This study presents a comprehensive analysis of the long-term water quality spatial and temporal trends in the rivers of Minas Gerais, Brazil, from 1997 to 2022. For this aim, we use data from 675 water quality stations monitored by the Minas Gerais Institute for Water Management (IGAM). The study focuses on evaluating the risk of exceeding the established limits for class 2, as defined by the guidelines in CONAMA 357/2005. The analysis includes parameters related to organic matter, nutrients, and metals, which are related to aspects such as agriculture runoff, urban and mining activities, and vegetation cover. The results indicate an overall decrease in the risk of threshold transgressions for most water quality parameters over the past 25 years, suggesting improved control of point and diffuse sources in the State, with the dissolved iron being the main exception. Despite, the study has some caveats, such as irregular samples in term of temporal intervals and spatial coverage, besides the lack of simultaneous flow measurements. The study also indicates that higher concentrations of the analyzed parameters are related to areas with intense urbanization and mining activities. In this context, the exploratory analysis can serve as a supporting tool for planning and managing the water resources in Minas Gerais.