Brazilian Mining Dam Collapse: Molecular Networking–Guided Metabolomics Reveals Species-Specific Plant Detox

In November 2015, a catastrophic environmental disaster struck the state of Minas Gerais, Brazil, which was caused by the collapse of the Fundão dam. Over 40 million m³ of metal-rich mining waste, containing iron, arsenic, mercury, cadmium, and manganese, contaminated more than 650 km of the Doce River basin, causing severe degradation of terrestrial and aquatic ecosystems. While immediate effects included widespread destruction of local habitats, including indigenous settlements, some endemic plant species exhibited remarkable resilience, adapting their metabolism to tolerate extreme exposure to toxic mining waste. Using an untargeted liquid chromatography-tandem mass spectrometry (LC-MSⁿ) metabolomics workflow integrated with multivariate analysis and molecular networking, we profiled metabolic changes in two medicinal plants, <i>Vernonanthura polyanthes</i> (Asteraceae) and <i>Piper aduncum</i> (Piperaceae). Our results showed that exposure to toxic mining waste elicited species-specific responses, with plants triggering biosynthetic pathways that enhanced production of peptides, especially glutathione and lysine-acetylated derivatives, for <i>V. polyanthes</i>, and phenylpropanoids, especially <i>O</i>-methylated <i>C</i>-glycosylated flavonoids, for <i>P. aduncum</i>. These shifts are consistent with defense mechanisms involving metal chelation and redox buffering, whereby glutathione-based peptides and flavonoids mitigate metal toxicity and oxidative stress in plant tissues. Overall, these findings shed light on the mechanisms of plant response under extreme environmental disturbance, providing insights into how metabolic adaptations contribute to ecological stabilization and plant recovery.