Hidden River Contamination from Critical-Metal Mining Demands Proactive Monitoring and Forecasting

Thallium (Tl) is a toxic metal. Its contamination in aquatic ecosystems is likely to intensify in the upcoming decades. Exploding demand for Li, rare earths, Co, Ni and Cu is pushing mining into various Tl-enriched ores/deposits. Every new battery, wind-turbine and power line therefore may carry a hidden Tl footprint that conventional lime-dosing treatment fails to retain. Thus, the low-carbon transition may turn Tl into an unexpected river contaminant. Field-to-lab experiments reveal that Tl⁺ mimics K⁺ in fish gills and algal cells, inducing oxidative stress, and Na⁺/K⁺-ATPase collapse at very low concentrations. These impacts may induce a series of alterations at the physiological, biochemical, and genomic expression levels. These disruptions can, in turn, undermine the survival and demographic structure of these organisms, ultimately posing risks to human beings via complex trophic networks. Given the urgency of this situation, it is therefore suggested that Tl should be incorporated into routine river-health monitoring in mining-impacted basins and propose a cost-effective proxy-screening and forecasting protocol.