Manganese: The overlooked contaminant in the world largest mine tailings dam collapse

Autor(es)

Queiroz, Hermano M. ^[1] ; Ying, Samantha C. ^{[2, 3]} ; Abernathy, Macon ^[3] ; Barcellos, Diego ^[1] ; Gabriel, Fabricio A. ^[4] ; Otero, Xose L. ^[5] ; Nobrega, Gabriel N. ^[6] ; Bernardino, Angelo F. ^[4] ; Ferreira, Tiago O. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo ESALQ USP, Luiz de Queiroz Coll Agr, Ave Padua Dias 11, BR-13418900 Piracicaba, SP - Brazil

^[2] Univ Calif Riverside, Dept Environm Sci, Riverside, CA 92521 - USA

^[3] Univ Calif Riverside, Environm Toxicol Grad Program, Riverside, CA 92521 - USA

^[4] Univ Fed Espirito Santo, Dept Oceanog, Grp Ecol Benton, BR-29075910 Vitoria, ES - Brazil

^[5] Univ Santiago Compostela, Fac Biol, CRETUS, Dept Edaphol & Agr Chem, Campus Sur, Santiago De Compostela 15782 - Spain

^[6] Fed Fluminense Univ, Dept Geochem, Grad Program Earth Sci Geochem, Niteroi, RJ - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Environment International; v. 146, JAN 2021.
• Citações Web of Science: 0

Resumo

Manganese (Mn) is an abundant element in terrestrial and coastal ecosystems and an essential micronutrient in the metabolic processes of plants and animals. Mn is generally not considered a potentially toxic element due to its low content in both soil and water. However, in coastal ecosystems, the Mn dynamic (commonly associated with the Fe cycle) is mostly controlled by redox processes. Here, we assessed the potential contamination of the Rio Doce estuary (SE Brazil) by Mn after the world's largest mine tailings dam collapse, potentially resulting in chronic exposure to local wildlife and humans. Estuarine soils, water, and fish were collected and analyzed seven days after the arrival of the tailings in 2015 and again two years after the dam collapse in 2017. Using a suite of solid-phase analyses including X-ray absorption spectroscopy and sequential extractions, our results indicated that a large quantity of Mn-II arrived in the estuary in 2015 bound to Fe oxyhydroxides. Over time, dissolved Mn and Fe were released from soils when Fe-III oxyhydroxides underwent reductive dissolution. Due to seasonal redox oscillations, both Fe and Mn were then re-oxidized to Fe-III, Mn-III, and Mn-IV and re-precipitated as poorly crystalline Fe oxyhydroxides and poorly crystalline Mn oxides. In 2017, redox conditions (Eh: -47 +/- 83 mV; pH: 6.7 +/- 0.5) favorable to both Fe and Mn reduction led to an increase (similar to 880%) of dissolved Mn (average for 2015: 66 +/- 130 mu g L-1; 2017: 582 +/- 626 mu g L-1) in water and a decrease (similar to 75%, 2015: 547 +/- 498 mg kg(-1); 2017: 135 +/- 80 mg kg(-1)) in the total Mn content in soils. The crystalline Fe oxyhydroxides content significantly decreased while the fraction of poorly ordered Fe oxides increased in the soils limiting the role of Fe in Mn retention. The high concentration of dissolved Mn found within the estuary two years after the arrival of mine tailings indicates a possible chronic contamination scenario, which is supported by the high levels of Mn in two species of fish living in the estuary. Our work suggests a high risk to estuarine biota and human health due to the rapid Fe and Mn biogeochemical dynamic within the impacted estuary. (AU)

• Processo FAPESP: 18/08408-2 - Estudos comparativos de transformações minerais de nanopartículas de óxidos de ferro em solos e sedimentos afetados por rejeitos de mineração e seus impactos na mobilização e fixação de metais pesados em dois ambientes redox contrastantes
• Beneficiário: Tiago Osório Ferreira
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 18/04259-2 - Biogeoquímica de ferro e seu controle sobre a dinâmica de metais traço nos solos do estuário do Rio Doce após o "desastre de Mariana"
• Beneficiário: Hermano Melo Queiroz
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 19/19987-6 - Solos e plantas do estuário do Rio Doce e seu controle sobre a biogeoquímica de ferro e metais em resposta ao desastre de Mariana (MG)
• Beneficiário: Tiago Osório Ferreira
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 19/17413-2 - Processos redox controlando a dinâmica de metais associados a óxidos de Fe no sedimentos do estuário do rio Doce após o desastre de Mariana
• Beneficiário: Hermano Melo Queiroz
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 19/02855-0 - Flutuações redox, dinâmica de ferro e metais em solos do estuário do Rio Doce após o "desastre de Mariana (MG)": uma abordagem experimental
• Beneficiário: Diego Barcellos
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado