Climate and anthropogenic activities control the concentrations of copper, zinc, cadmium and chromium in global inland waters

Abstract

Pollution by heavy metals (Cu, Zn, Cd, Cr) in global inland waters poses significant threats to freshwater biodiversity and ecosystem function, yet the global patterns and drivers of heavy metals remain poorly explored. Here, assessing using 11,573 data points collected from 514 peer-reviewed publications, key advances include: (1) quantification of median concentrations in global inland waters (Cu: 8.38, Zn: 30.00, Cd: 0.53, and Cr: 7.00 μg L−1), providing global-scale reference values to contextualize local water quality assessments; (2) anthropogenic activities, temperature, actual evapotranspiration, precipitation and runoff dominantly control the concentrations of heavy metals in inland waters, and (3) global heavy metal pollution hotspots were established, revealing significantly elevated concentrations in West and South Asia and Africa, followed by South America. Our study provides a comprehensive analysis of inland water for Cu, Zn, Cd, and Cr, offering a scientific foundation for targeting pollution control in vulnerable regions under climate change.