Comparative Analysis of Metals in Seafood from Rio Doce Coastal Areas and Regional Fish Markets

Abstract

On November 5, 2015, the Fundão Dam breached (the “Event”), releasing water, tailings, dam construction material, and debris to downstream watercourses. Over 20 million cubic meters of fine particles from the tailings, as well as scoured soil and sediments, reached the Rio Doce estuary and surrounding marine area 17 days later. Fishing was banned by the Federal Court of Espírito Santo in February 2016. The fishing ban area included the coastal area near the mouth of the Rio Doce and seaward to a depth of 25 meters, south to Barra do Riacho, and north to Degredo Beach. In June 2019, the Brazilian health agency, Anvisa, published a risk assessment for fish consumption which recommended daily consumption limits for fish of 200 grams for adults and 50 grams for children for both continental and coastal areas of the Rio Doce basin. Comparative analyses were performed between metal concentrations in marine fish and crustaceans collected in the banned fishing area to reference areas and commercialized seafood markets along the Brazilian coast. The results reveal that metals detected in seafood tissue collected in the fishing ban area are not significantly different than other reference areas or from commercially available seafood. This result indicates that elevated metal concentrations in seafood are a regional problem, unrelated to the Event. Higher concentrations of metals in fish in reference areas outside of the fishing ban area as well as in commercial seafood markets demonstrates that the risk management approach of a localized fishing ban is ineffective for reducing risk to the population related to seafood consumption.