Details

Autor(en) / Beteiligte

• Aguiar, Valquíria Maria de Carvalho
• Neto, José Antônio Baptista
• Quaresma, Valéria da Silva
• Bastos, Alex Cardoso
• Athayde, João Pedro Moreno de

Titel

Bioavailability and ecological risks of trace metals in bottom sediments from Doce river continental shelf before and after the biggest environmental disaster in Brazil: The collapse of the Fundão dam

Ist Teil von

• Journal of environmental management, 2020-10, Vol.272, p.111086-111086, Article 111086

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The present study deals with bioavailability of trace metals in the Doce river continental shelf, southeast of Brazil. The bottom sediments of the study area were firstly sampled a few weeks before the biggest environmental disaster of Brazil, the collapse of the Fundão dam in November of 2015. The disaster released around 40 Mm3 of iron ore tailings into Doce river basin and an estimate of 10 Mm3 reached the river delta, having the adjacent continental shelf as the final destination. One year and a half later, on April of 2017, the continental shelf was sampled again. A total of 48 stations were evaluated concerning concentrations of trace metals (Zn, Cu, Pb, Ni, Cr) and other ancillary variables before and after the accident. Trace metals were determined through fractionation in order to assess mobility and establish the ecological risk through RAC index. Before the accident, trace metals mobility was Pb > Ni > Cu > Zn > Cr, with Pb Cu, Ni and posing high ecological risk (RAC>30%) in many stations. Differences in concentrations of metal from pre to post accident were significant, and the increase of trace metals was observed. The mobility order after the accident changed to: Cu > Pb > Ni > Zn > Cr. Metal fractionation showed remarkable changes after the accident, with elements such as Cu, Ni and Zn highly associated with reducible fractions originated from the tailings composition. Despite the decrease of RAC to medium risk after the accident in most stations, the bioavilability of Cu, Pb, Ni and Zn increased as show by their higher accumulation in the bioavailable fractions. •Fundão dam collapsed in 2015 releasing 40 Mm3 of mining tailings in Doce river basin.•Lead (Pb), nickel (Ni), copper (Cu), chromium (Cr), zinc (Zn) were fractionated.•Pb, Ni, Cu, Cr and Zn were evaluated concerning bioavailability in sediments.•Before the accident mobility was Pb > Ni > Cu > Zn > Cr posing high ecological risk .•After the accident mobility was Cu > Pb > Ni > Zn > Cr and fractionation changed remarkably.