In the context of the Doce river (Southeast Brazil) Fundão dam disaster in 2015, we monitored the changes in concentrations of metal(loid)s in water and sediment and their particulate and dissolved partitioning over time. Samples were collected before, during, and after the mine tailings arrival to the Doce river estuary (pre-impact: 12, 10, 3 and 1 day; acute stage: tailing day – TD and 1 day after – DA; chronic stage: 3 months and 1 year post-disaster). Our results show that metal(loid) concentrations significantly increased with time after the disaster and changed their chemical partitioning in the water. 35.2 mg Fe L−1 and 14.4 mg Al L−1 were observed in the total (unfiltered) water during the acute stage, while aqueous Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn concentrations all exceeded both Brazilian and international safe levels for water quality. The Al, Fe and Pb partitioning coefficient log (Kd) decrease in the acute stage could be related to the high colloid content in the tailings. We continued to observe high concentrations for Al, Ba, Cd, Cr, Cu, Fe, V and Zn mainly in the particulate fraction during the chronic stage. Furthermore, the Doce river estuary had been previously contaminated by As, Ba, Cr, Cu, Mn, Ni and Pb, with a further increase in sediment through the tailing release (e.g. 9-fold increase for Cr, from 3.61 ± 2.19 μg g−1 in the pre-impact to 32.16 ± 20.94 μg·g−1 in the chronic stage). Doce river sediments and original tailing samples were similar in metal(loid) composition for Al, As, Cd, Cr, Cu, Fe, V and Zn. As a result, these elements could be used as geochemical markers of the Fundão tailings and considering other key parameters to define a baseline for monitoring the impacts of this environmental disaster.
Bibliographical noteFunding Information:
The authors are grateful to Instituto Chico Mendes de Biodiversidade (ICMBio) for supporting the sampling surveys and LabPosseidon at Federal University of Espírito Santo (Brazil) for providing salinity and temperature data for the 3 months post-disaster survey. We are also thankful to the Brazilian Federal Police, Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis (IBAMA) and Instituto Estadual de Meio Ambiente e Recursos Hídricos (IEMA) for providing original tailing samples. LEOG is supported by a PELD-HCES scholarship. AFB was supported by FAPES , CAPES and CNPq grants N 77683544/2017 and 301161/2017–8 .
- Geochemical marker
- Metal(loid)s contamination
- Mine tailing disaster
- Samarco, Brazil