Long-term impacts on estuarine benthic assemblages 4.2 years after a mine tailing spill in SE Brazil

Coppo, G. C.; Gabriel, F. A.; Mazzuco, A. C. A.; Queiroz, H. M.; Barcellos, D.; Ferreira, T. O.; Bernardino, A. F.

doi:10.1101/2023.08.25.554820

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bioRxiv · 10.1101/2023.08.25.554820

Long-term impacts on estuarine benthic assemblages 4.2 years after a mine tailing spill in SE Brazil

Coppo, G. C.·Gabriel, F. A.·Mazzuco, A. C. A.·Queiroz, H. M.·Barcellos, D.·Ferreira, T. O.·Bernardino, A. F.

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Abstract

The Rio Doce estuary was critically impacted in 2015 by the worlds largest mining tailing spill, with still unclear long-term effects. Here we present a long-term (2015 to 2020) assessment of estuarine benthic assemblages, where Annelida and Mollusca were dominant (52.6% and 26.3%, respectively). Our results demonstrated that the density and richness of benthic taxa decreased in response to an increase in potentially toxic elements concentrations, suggesting a chronic pollution effect that lasted for at least 4.2 years in the estuary. Our data demonstrated that despite the decline in sediment potentially toxic elements concentration over time, there was a continued low habitat quality for the benthic fauna characterized by a reduction of 96% on macroinvertebrate density and 48% on species richness. The long-term impacts on benthic macrofauna highlight that water quality levels can misguide impact assessment programs, and reveal that mine tailings impacts persist for many years in estuarine ecosystems.

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Coppo, G. C., Gabriel, F. A., Mazzuco, A. C. A., Queiroz, H. M., Barcellos, D., Ferreira, T. O., Bernardino, A. F.. 2023-08-27. Long-term impacts on estuarine benthic assemblages 4.2 years after a mine tailing spill in SE Brazil. https://doi.org/10.1101/2023.08.25.554820

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