Has the Rio Doce "time bomb" been defused? Using a weight-of-evidence approach to determine sediment quality

Second Fundão Dam Rupture Science Meeting: Updating the science

The second Fundão Dam Rupture Science Meeting was held in Ouro Preto, Minas Gerais, Brazil, on 21 and 22 September 2022. A total of 100 delegates attended the meeting, which featured high-quality oral presentations and posters over the two days and lively discussions of the science presented. The meeting resulted in nine papers being published in this special series. In the discussion, it was commented that the first meeting had been more a meeting of competitive perspectives but that the second meeting featured a more collaborative sharing of knowledge. Also, there had been substantial improvement in ways to deal with the lack of pre-event data and account for other stressors in the system, and as a result, stronger conclusions regarding the recovery rates of the system were able to be made. Importantly, there was no evidence for a feasible "time bomb" of a future catastrophic release of contaminants, but it was agreed that different scenarios continue to be researched. Integr Environ Assess Manag 2024;20:70-73. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Long-term impacts on estuarine benthic assemblages (2015-2020) after a mine tailing spill in SE Brazil

The Rio Doce estuary was critically impacted in 2015 by the world's largest mining tailing spill, with still unclear long-term effects on the aquatic biota. Here we present a long-term (2015 to 2020) assessment of estuarine benthic assemblages, where we demonstrate that despite a decline in the absolute concentrations of potentially toxic elements; sediment contamination is still above pre-impact conditions. The presence of these contaminants is likely responsible for a continued low habitat quality for the benthic fauna, characterized by a reduction of 96 % of the macroinvertebrate density and persistent change in the benthic assemblage composition. Our study supports previous work indicating the long-term nature of pollution impacts in estuaries, and demonstrate that although water quality levels were quickly adequate under regulatory terms, they largely lack significance to the overall ecosystem health assessment, as they are not related to the recovery of bottom- dwelling assemblages in estuarine ecosystems.