Efeito crônico do rompimento da barragem do Fundão sobre a dinâmica espaço/temporal da qualidade da água do rio Doce

Abstract

In 2015, the biggest environmental disaster in Brazil occurred, in which approximately 43 million cubic meters of ore tailings from the Fundão dam reached hundreds of kilometers from the entire Doce river channel to its mouth in Espírito Santo, causing several environmental and social impacts. One of the aspects of the vulnerability of this event was the water quality, given that in the first days of the disaster, changes in several parameters and animal mortality were detected. However, the long-term effects are still not well elucidated. Therefore, the objective of this study is to answer whether the dam rupture chronically altered the quality of the water affected by the tailings. To carry out this investigation, the GAMLSS model was used, a method little explored in aquatic data. We evaluated the dynamics of the Doce River, analyzing the relationship between the values of water quality parameters, the seasonal variation of these parameters, and the effect of the distance from the dam between the periods before and after the disaster. In our work, we showed that the effects of the dam collapse remain chronically in the impacted watercourse. The values of the physical-chemical parameters evaluated jointly or seasonally. In turn, the relationship between water quality and distance from the dam was not observed. The prolonged effect possibly has as its main cause the exposure in the water column of the tailings fraction that was deposited in the river sediment. The GAMLSS model proved to be adequate in the analysis of time series of water quality, adjusting well to the data, being a promising approach for future studies in the context of increasing changes in water courses.