Environmental, ecotoxicological, and human health impacts of a major tailings dam collapse: a systematic review of current knowledge and research gaps

of iron ore tailings and ranking among the world's worst mining disasters. This systematic review synthesizes the current knowledge and identifies research gaps. Selected articles (n = 102) were organized into four thematic axes: Physicochemical and mineralogical characterization of the tailings; Environmental contamination; Ecological and ecotoxicological effects; and Human health impacts. The tailings are mainly ferruginous, composed of quartz and iron oxides/hydroxides. Half of contamination-focused studies (i.e. 37) investigated associations between measured environmental parameters and the dam collapse, with 36 reporting at least partial correlations with the released tailings. Despite this reported correlation, several studies also indicate additional contamination sources and/or other influencing factors (e.g., seasonality). In situ ecotoxicological studies have focused mainly on fish, while ex situ studies have covered a wider range of aquatic and terrestrial organisms. Human health investigations have reported physical and mental health impacts across different population groups. Despite the efforts, major trends and gaps remain: an overemphasis on abiotic compartments; limited field-based assessments of biotic responses, assessment of soil recovery and trace-element trophic transfer; insufficient evaluation of metal accumulation in fish for subsistence consumption; absence of long-term ecological monitoring studies, and an almost complete absence of studies on atmospheric contamination by resuspended tailings. Overall, available evidence indicates severe but gradually diminishing impacts, highlighting the need for integrated, multi-compartmental, and long-term studies to support restoration, risk assessment, and the protection of life in the Paraopeba River Basin.