Biochemical response and metals bioaccumulation in planktonic communities from marine areas impacted by the Fundao mine dam rupture (southeast Brazil)

The rupture of the Fundao dam (Mariana, MG, southeast Brazil) released a huge flood of mine tailings to Doce river basin and its adjacent coastal area, in November 2015. This catastrophic event exposed aquatic communities to metal contamination related to mine tailings, but its biological effects are still poorly understood. This study investigates how biochemical response related to metal exposure vary between locations and seasons during the years of 2018-2020, in planktonic communities (micro and mesoplankton). Marine microplankton collected in sectors in front and south of the Doce river mouth presented the highest lipid peroxidation (LPO) and induc-tion of metallothioneins (MT). Mesoplankton collected in sectors in front and north of the Doce river mouth pre-sented highest LPO, while MT in this size class did not respond to a clear spatial pattern. Our results showed that metals affected biomarkers in a non-linear pattern and highlighted the complex relationship between metals, biochemical parameters, and seasonality. The variation in biochemical biomarkers indicates physiological stress related to metals, once sectors contaminated by metals, especially Fe, Mn and Cd, presented stronger biochemical responses. Comparison of metal levels with bioaccumulation data collected before the impact indicates Fe, Cd, Cr and Cu more than 2-fold higher after disaster in sectors closer to the river. Literature showed that these sectors present zooplanktonic assemblages with lower biomass and biodiversity, suggesting that the opportunistic species that thrives in the area are also under biochemical stress, but possibly relies on repair or defense mechanisms. The physiological stress detected by this study is possibly related to the mine tailings, considering the metals that stood out and the proximity with the Doce river mouth. This suggests that the impacts related to the failure of Fundao dam are still affecting the marine planktonic community even three to four years after the environmental disaster. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the variation in biochemical response related to metal exposure among planktonic communities (micro and mesoplankton) in different locations and seasons from 2018-2020. The results showed that metals affected biomarkers in a non-linear pattern, indicating physiological stress related to metal contamination, especially in sectors contaminated by Fe, Mn, and Cd. The study highlights the complex relationship between metals, biochemical parameters, and seasonality in the marine planktonic community impacted by the Fundao dam rupture.