A synthesis on the spread of the tailing plumes resulting from the Fundão dam collapse along the Brazilian coast: integrating evidence from multiple sources

Abstract

The rupture of the Fundão Dam, on November 5, 2015, released 40–60 million cubic meters of iron ore tailings, causing the most severe environmental disaster in Brazil's history. At the Atlantic Ocean, the tailings formed extensive sediment plumes that spread into coastal and offshore environments, threatening important marine ecosystems. Numerous studies have sought to assess the spatial extent of these plumes using diverse methodologies, including aerial surveys, satellite imagery, numerical modelling, and geochemical analyses, with differences in spatial coverage and analytical focus leading to varying conclusions. Here, we conducted a comprehensive synthesis on the spread of Fundão Dam tailing plumes along the Brazilian coast. Assessing 20 documents, including technical reports and peer-reviewed articles, we synthesized evidence over the inferred limits of high- and low-intensity plumes and the temporal coverage, stemming from different methodologies. Some consistent findings were identified (i) plume dispersion occurred predominantly southward, driven by winds and oceanic currents, with high-intensity plumes affecting protected areas near the Doce River mouth; (ii) plume extent varied seasonally due to river discharge; and (iii) wind reversal events promoted northward expansion, likely reaching the Abrolhos Bank. Through evidence aggregation, we found strong support for plume presence along 500 km of coastline, encompassing the entire Espírito Santo coast and parts of northern Rio de Janeiro and southern Bahia. By synthesizing multiple lines of evidence, this review strengthens conclusions regarding the drivers and spatial spread of plumes while reducing biases and limitations linked to each methodology.