Soil-plant interaction in the Doce River Estuary: a dendrochemical approach and the dynamics of potentially toxic elements in soil affected by mine tailings

Abstract

In 2015, the Fundão Dam - owned by the mining company Samarco - broke down, pouring 60 million m3 of iron mine tailings into the Doce River. This is considered the worst accident in the mineral sector in history and the biggest environmental accident in Brazil, known as "Mariana Disaster". Pollutants impacted soil quality, estuarine benthic assemblies, water quality along the Doce River, causing severe ecological and social damage. There is a great controversy regarding the contamination of the areas affected by the tailings of the "Mariana Disaster" by Potentially Toxic Elements (PTE). To clarify this controversy, dendrochemical analyzes on tree growth rings can be used for the retrospective assessment of environmental changes, functioning as natural proxies of environmental conditions. Furthermore, environmental quality can be studied through the ability of living organisms to accumulate chemical elements, being considered as "biomonitors". The objective of the present project will be to elucidate and clarify the existing controversy about the contamination of the Doce River Estuary, using the dendrochemical analysis, carrying out an assessment of the environmental condition and the presence of PTE in the Doce River Estuary in the pre and post environmental catastrophe conditions. In addition, we intend to understand and monitor the condition of soil contamination through chemical analysis of tree tissues and their relationship with the soil of the estuary. (AU)