Spatial–temporal variations of metals and arsenic in sediments from the Doce River after the Fundão Dam rupture and their bioaccumulation in Corbicula fluminea

Abstract

The rupture of the Fundão dam in Brazil released tons of mining tailings into the Doce River Basin (DRB). This investigation aimed to determine the bioaccumulation of metals in soft tissues of the bivalve Corbicula fluminea exposed to sediments collected in the DRB in four periods (just after, 1, 3, and 3.5 years after the dam rupture). In the exposure bioassays, the concentrations of Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in sediments and bivalve soft tissues were quantified. The concentration of some elements (As, Cd, Mn, and Al) in sediments exceeded the federal limits or regional backgrounds at some sampling sites, but their concentrations tended to decrease over time. However, higher concentrations of many elements were detected in the winter of 2019. Several elements were detected in C. fluminea soft tissues, but the bioaccumulation factors were generally low or not related to those elements associated with the ore tailings, evidencing that the bioavailability of metals to bivalves, in laboratory conditions, was limited. Integr Environ Assess Manag 2023;00:1–12. © 2023 SETAC

Second Fundão Dam Rupture Science Meeting: Updating the science

“…We learned that water quality, when compared with relevant controls (tributaries), had improved and that more than six years after the incident had returned to within catchment norms for the parameters being monitored (Wild et al, 2023). We learned that upon exposure of sediment-dwelling organisms to impacted sediments, there was very little change in bioaccumulation of metals or metalloids under the control of the geochemistry of the iron oxyhydroxides that made up the bulk of the tailings (de Figueiredo Eufrasio Pauly et al, 2023) and, in the Rio Doce catchment, workers need to be mindful that the substances being considered might have sources other than the tailings (Kananizadeh et al, 2023). We noted that we should remember that the tributaries make the river, and we have to be mindful of what is carried by those tributary catchments, too (Wild et al, 2023).…”