Polycyclic aromatic hydrocarbons in estuarine sediments as a consequence of the mine tailings remobilization and transport in the Rio Doce basin

The Fundão dam failure in 2015 severely impaired the economy, the lives of riverine communities, and the aquatic ecosystems of the Rio Doce basin in southeast Brazil. Several contaminants, including polycyclic aromatic hydrocarbons (PAHs), were transported downstream, deposited in the estuary, and r...

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Bibliographic Details
Published in:Integrated environmental assessment and management 2024-01, Vol.20 (1), p.169-178
Main Authors: Silva, Cesar A., Zacché, Danillo S., Lehrback, Bethânia D., Cagnin, Renata C., Costa, Eduardo S., Longhini, Cybelle M., Bernardino, Angelo F., Sá, Fabian, Neto, Renato R.
Format: Article
Language:English
Subjects:
Aquatic ecosystems
Aromatic compounds
Aromatic hydrocarbons
Benthos
Biomass burning
Brackishwater environment
Brazil
Classification (sedimentation)
Contaminants
Contamination
Dam failure
Ecological effects
Ecosystem
Environmental Monitoring - methods
Environmental risk
Estuaries
Estuarine dynamics
Estuarine sediment
Fossil fuels
Geologic Sediments
Mine tailings
Mine wastes
Mining tailings
Polycyclic aromatic hydrocarbons
Polycyclic Aromatic Hydrocarbons - analysis
Rio Doce
Samarco
Sediment
Sediments
Tailings
Water Pollutants, Chemical - analysis
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Summary:The Fundão dam failure in 2015 severely impaired the economy, the lives of riverine communities, and the aquatic ecosystems of the Rio Doce basin in southeast Brazil. Several contaminants, including polycyclic aromatic hydrocarbons (PAHs), were transported downstream, deposited in the estuary, and released into the Atlantic Ocean. The high concentration of PAHs in estuarine sediments may pose ecological risks and deleterious effects to benthic organisms, so here we aimed at determining the source and fate of these compounds before and after the tailings’ arrival. The mean concentration of the analyzed Σ16PAHs increased from 34.05 µg kg−1 in the prefailure period to 751.77 µg kg−1 one year after the arrival of the tailing. The classification of the sediment quality changed from low to moderate contamination. Our results suggest that there was PAHs remobilization by mine tailings along the Rio Doce basin. The target analytes exhibited mostly a pyrolytic profile from fossil fuel and biomass burning. In addition to other contaminants deposited in the estuary after the arrival of the tailings, this study revealed that the profile change of PAHs in the estuary region is a consequence of the mud's erosive power. Integr Environ Assess Manag 2024;20:169–178. © 2023 SETAC Key Points One year after the tailings arrived at the mouth, the average concentration of polycyclic aromatic hydrocarbons (PAHs) in the estuary increased 20 times. Sediment quality changed significantly from low to moderate and/or high contamination. The sources that contributed to the input of PAHs also changed over time, at first characterized by burning fossil fuels prior to arrival and transitioning to a mixed pyrolytic profile after the tailings arrived at the river's mouth. The compounds carried by the mud appear to be trapped in the estuary, creating a source of chronic contamination for the mouth and adjacent coastal areas.
ISSN:1551-3777
1551-3793
DOI:10.1002/ieam.4831