Long-term contamination of the Rio Doce estuary as a result of Brazil's largest environmental disaster

Author(s)

Gabriel, Fabricio A. ^[1] ; Ferreira, Amanda D. ^[2] ; Queiroz, Hermano M. ^[2] ; Vasconcelos, Ana Luisa S. ^[2] ; Ferreira, Tiago O. ^[2] ; Bernardino, Angelo F. ^[1]

Affiliation

^[1] Univ Fed Espirito Santo UFES, Dept Oceanog & Ecol, Grp Ecol Benton, Av Fernando Ferrari 514, BR-29075910 Vitoria, ES - Brazil

^[2] Univ Sao Paulo ESALQ USP, Dept Ciencia Solo, Escola Super Agr Luiz Queiroz, Alameda Palmeiras Agron, BR-13418900 Piracicaba, SP - Brazil

• Document type: Journal article
• Source: PERSPECTIVES IN ECOLOGY AND CONSERVATION; v. 19, n. 4, p. 417-428, OCT-DEC 2021.
• Web of Science Citations: 3

Abstract

The Rio Doce basin in SE Brazil was critically impacted in November 2015 by the spillage of millions of tons of mining waste. In the Rio Doce estuary, the tailings removed nearly 30% of estuarine benthic species and rapidly increased sediment contamination by metal(loid)s. Short-term impact assessments from 2015 to 2017 revealed severe ecological effects in the estuary linked to the deposited tailings, but the long-term patterns of contamination and their ecological risks are yet unclear. We analyzed the contamination and ecological risks of metal(loid) in the Rio Doce estuary up to 4.2 years after the short-term impacts in 2015. We found that 4.2 years after the impact, As, Cr, Cu, and Ni concentrations were still above the threshold effect levels of toxicity, while Cd and Pb exceeded probable effect levels. Although the concentrations of contaminants often show a stable temporal trend, sedimentary metal(loid) contents after the impact were continuously above the background values for the Rio Doce estuary. The ecological risk analysis suggested that sediment metal(loid) concentrations are high enough to cause adverse biological effects, supporting the hypothesis that there is chronic contamination of the estuarine ecosystem in the longterm. Our data suggests that without recovering actions, the Rio Doce estuary will likely be a sink of contaminants from the upper river basin. However, this capacity is limited due to the sensibility of Fe oxyhydroxides to reductive dissolution and metal(loid) release, leading to risks to the aquatic biota with potentially negative consequences to human health for decades to come. (C) 2021 Associacao Brasileira de Ciencia Ecol ogica e Conservacao. Published by Elsevier B.V. (AU)

• FAPESP's process: 18/04259-2 - Iron biogeochemistry and its control on dynamics of trace metals in the soils of Doce River estuary after the "Mariana disaster"
• Grantee: Hermano Melo Queiroz
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 19/14800-5 - Estuarine plants and their control in metals biogeochemistry in soils impacted by the `Mariana disaster´
• Grantee: Amanda Duim Ferreira
• Support Opportunities: Scholarships in Brazil - Doctorate