Immediate and long-term impacts of one of the worst mining tailing dam failure worldwide (Bento Rodrigues, Minas Gerais, Brazil)

https://doi.org/10.1016/j.scitotenv.2020.143697Get rights and content

Highlights

  • The Fundão dam failure is one of the largest environmental disasters in the world.

  • Immediately the tailings were mainly transported as suspended particulate matter.

  • After 6 months, with the deposition, the metal levels increased in the sediment.

  • Water and sediment induced negative biological and toxicogenetic effects.

  • This joint of abiotic and biotic indicators can direct other monitoring programs.

Abstract

The rupture of Fundão Dam is considered one of the largest environmental disasters in Brazilian history and one of the largest in the world involving tailings dams. The present study analyzed the changes in metal concentrations in the dissolved, suspended particulate matter (SPM) and sediment in the period just after (15 days) and six months after the dam rupture, together with the biological and cytogenotoxic effects, from the collapse site until the Doce River mouth in the Atlantic Ocean. After the dam rupture, the tailings were mainly transported as SPM. After six months, with the deposition, there was a decrease in metal concentrations in dissolved and SPM and increased levels were observed in the sediment. Cr, Ni, Cd and Hg levels in sediment were higher than the threshold effects level (TEL/NOAA), especially six months after the dam rupture. The water induced immediate negative biological effects at different levels of the trophic chain, together with Al, Fe, Mn and Zn accumulation in fish muscle. Both water and sediment also showed cytotoxic, genotoxic and mutagenic effects. These data demonstrate the importance of long-term monitoring with abiotic and biotic parameters to clarify the impacts of mining tailings and can help to direct future monitoring programs.

Introduction

Mining activity produces intense changes in the landscape to recover valuable minerals. The process involves extraction of large amounts of rock and soil, with intensive use of water, resulting in release of effluents such as tailings (Schoenberger, 2016). The material hydraulically retained by tailings dams is usually composed of fine particulate matter with greater weight (ICOLD, 2001). The volume and chemical characteristics of the tailings released by dam failure (particularly with potentially toxic metals) damage the whole affected area, including soils, rivers, plants, associated biota and local human populations (Burritt and Christ, 2018).

On November 2015, the rupture of Fundão Dam, located in southeastern Brazil, initially released at least 34 million m3 of iron ore mining residue, which flowed for more than 650 km through the Gualaxo do Norte, Carmo and Doce rivers until reach the Atlantic Ocean (IBAMA, 2015; Carmo et al., 2017) (Supplementary Video). Efforts were made to retain the remaining 16 million m3 in the tailings pond, but a considerable part also reached the sea. The volume of material released and resulting damage made this event the largest environmental disaster in Brazilian history, and one of the largest in the world involving tailings dams (Aires et al., 2018; Almeida et al., 2018; Burritt and Christ, 2018).

The volume of tailings led to an immediate increase in water turbidity, contamination of riverside soils, loss of native vegetation, including remnants of Atlantic Forest (a hotspot of biodiversity) and other places legally classified as “permanent protection areas” (Aires et al., 2018; Omachi et al., 2018). The damages were severe to water, sediment and associated fauna of the river courses, as well as the estuarine, coastal and marine environments (IBAMA, 2015; Carmo et al., 2017). Besides environmental damages, the social impacts were also severe, with the death of 19 people, pollution of the water supply, evacuation of the riverside population, restrictions on fishing activities and other water uses (such as irrigation), socioeconomic losses and sense of danger and helplessness among the affected population (IBAMA, 2015; Carmo et al., 2017; Hatje et al., 2017). Nowadays, the population is still fearful of the contamination risk due to the lack of transparency of the mining company and public environmental agencies.

The flow of tailings released not only the characteristic elements from the ore, predominantly Fe (45,200 ± 2850 mg·kg−1) and Mn (433 ± 110 mg·kg−1), but also toxic metals as Cr (63.9 ± 15.1 mg·kg−1), Pb (20.2 ± 4.6 mg·kg−1) (Queiroz et al., 2018), Hg (~75 ng·g−1), As (~719.07 ng·g−1) (Segura et al., 2016) and even the rare earth metals La (~414.57 ng·g−1) and Sc (~609.30 ng·g−1) (Segura et al., 2016). Despite efforts to quantify and monitor the impacts of the disaster on inland and coastal ecosystems, many uncertainties remain more than four years after the dam rupture. The initial impact of the tailings as source of metals was demonstrated, but the fluctuations in metal levels with time have not been confirmed yet and the long-term effects are not clearly described. This material was eventually deposited in riverside soils and river bottom sediments, which can be absorbed by organisms of the local food chain.

Among the biological consequences of tailings release are changes in microbial communities (Cordeiro et al., 2019), algae physiology (Costa et al., 2019), benthic macrofauna (Oliveira Gomes et al., 2017) and larval fish assemblages (Bonecker et al., 2019), beyond alteration in liver morphology of the fish species (Weber et al., 2020). However, some of these studies are restricted to marine or estuarine areas or only cover restricted areas of the Doce River. Considering the magnitude of the accident, there are still few studies reporting the immediate and long-term impacts of the tailings release on biological organisms. Therefore, there is still a need to evaluate the impacts along the affect area, including evaluation of the metal accumulation in the biota, to enable inferences about the continuing risks to the human population.

Toxicological tests using different indicator organisms are an important tool for water quality monitoring. The use of species with distinct position level can help to assess the impacts along the food chain. Genetic toxicity bioassays are also recommended to monitor the quality of impacted areas, because they shed light on the action of compounds with cytotoxic, genotoxic and/or mutagenic properties, like heavy metals. Nevertheless, only a few studies have focused on the biological and cytogenotoxic potential the compartments of the Doce River after the iron ore tailings release. Moreover, many of the studies were restricted to one or two sampling sites (Gomes et al., 2019; Quadra et al., 2019). Therefore, considering the dimensions of the disaster and its potential impacts on exposed organisms and human populations, it is important to investigate the biological and cytogenetic impact of the tailings in the Doce River as a function of time and distance from the dam.

The present study investigated the changes in metal concentrations in the dissolved, suspended particulate matter and sediment in the period just after (15 days) and six months after the rupture of the tailings dam, together with the biological and cytogenetic effects of the tailings, from the collapse site until the mouth of the Doce River at the Atlantic Ocean. These data are important to understand the metal dynamics along time and the long-term biological impacts of this massive accident, to support actions to restore and protect the Doce River watershed and similar impacted areas worldwide.

Section snippets

Study area and sampling

Fundão Dam belongs to the Germano mining complex, in the Bento Rodrigues district located in the municipality of Mariana in Minas Gerais State, southeastern Brazil. The dam was storing some 50 million m3 of iron ore tailings, of which at least 34 million m3 was released directly into the Doce River basin (Supplementary Video). On November 5, 2015, with the dam rupture, the tailings reached the Santarém Dam just in downstream, then flowed through the Gualaxo do Norte River until reaching the

Elements in the dissolved and suspended particulate matter

With the dam rupture (sampling 1), the tailings released were mainly transported as SPM, raising the turbidity levels (Table 1). After the dam rupture (sampling 1–15 days) the SPM showed the predominance of Fe (mean value: 121.7 mg·L−1), Cr (mean value: 91.05 mg·L−1), Al (mean value: 64.60 mg·L−1), Cu (mean value: 24.92 mg·L−1), Pb (mean value: 20.84 mg·L−1), Cd (mean value: 14.10 mg·L−1), together with the rare earth metals La (mean value: 184.99 mg·L−1), Y (mean value: 74.24 mg·L−1), Gd (mean

Discussion

After the dam rupture, the fine particulate matter of the tailings induced an increase in turbidity levels and metal distribution along the whole course of the Doce River until the Atlantic Ocean. Therefore, the SPM was a relevant environmental matrix for the dispersion of metals along the river until its mouth (Hatje et al., 2017). The present study demonstrates that in the long term (six months after the rupture), the SPM settled as bottom sediment, increasing the metal levels together with

Conclusions

The present study demonstrated the immediate and long-term (after six months) impact of the Fundão tailings dam rupture on metal concentration together with the biological and toxicogenic potential of the water (with large amount of SPM) and sediment. Suspended particulate matter was an important geochemical support for metal transport just after the rupture, and with time this material was transported to the mouth and into the ocean, or underwent precipitation by oxy and hydro colloidal iron

CRediT authorship contribution statement

Cristiane dos Santos Vergilio: Conceptualization, Investigation, Resources, Writing - original draft, Writing - review & editing, Visualization, Supervision, Project administration. Diego Lacerda: Writing - review & editing, Formal analysis, Data curation, Visualization. Tatiana da Silva Souza: Investigation, Methodology, Supervision. Braulio Cherene Vaz de Oliveira: Methodology, Validation, Data curation. Vinicius Sartori Fioresi: Methodology. Victor Ventura de Souza: Methodology. Giovana da

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

The authors are grateful for the support from the Laboratório de Ciências Ambientais (LCA) and to the Programa de Pós-Graduação em Ecologia e Recursos Naturais from the Universidade Estadual do Norte Fluminense Darcy Ribeiro, the Laboratório de Morfologia Animal, the Laboratório de Ecotoxicologia (LABTOX) and the Laboratório de Estudos em Ciências Ambientais (LECA) from the Universidade Federal do Espírito Santo – Campus Alegre for use of the infrastructure. The authors thank the financial

References (42)

  • K.S.S. Oliveira et al.

    Temporal variability in the suspended sediment load and streamflow of the Doce River

    J. S. Am. Earth Sci.

    (2017)
  • C.Y. Omachi et al.

    Atlantic Forest loss caused by the world´ s largest tailings dam collapse (Fundão dam, Mariana, Brazil)

    Remote. Sens. App. Soc. Environ.

    (2018)
  • G.R. Quadra et al.

    Far-reaching cytogenotoxic effects of mine waste from the Fundão dam disaster in Brazil

    Chemosphere

    (2019)
  • V.S. Quaresma et al.

    The effects of a tailing dam failure on the sedimentation of the eastern Brazilian inner shelf

    Continental Shelf Research

    (2020)
  • H.M. Queiroz et al.

    The Samarco mine tailing disaster: a possible time-bomb for heavy metals contamination?

    Science of the Total Environment

    (2018)
  • S.M. Sakan et al.

    Assessment of heavy metal pollutants accumulation in the Tisza river sediments

    J. Environ. Manag.

    (2009)
  • E. Schoenberger

    Environmentally sustainable mining: the case of tailings storage facilities

    Res. Policy

    (2016)
  • F.R. Segura et al.

    Potential risks of the residue from Samarco’s mine dam burst (bento Rodrigues, Brazil)

    Environ. Pollut.

    (2016)
  • A.A. Weber et al.

    Effects of metal contamination on liver in two fish species from a highly impacted neotropical river: a case study of the Fundão dam, Brazil

    Ecotoxicol. Environ. Saf.

    (2020)
  • ABNT

    ABNT NBR 12713:2016 - Ecotoxicologia aquática - Toxicidade aguda - Método de ensaio com Daphnia spp (Crustacea, Cladocera) 27

    (2016)
  • ABNT

    ABNT NBR 15088:2016 - Ecotoxicologia aquática - Toxicidade aguda - Método de ensaio com peixes (Cyprinidae)

    (2016)
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