Driving factors and health risks of spatiotemporal variations of heavy metal pollution in groundwater of pyrite mining areas in the middle and upper reaches of the Yangtze River in China

Groundwater heavy metal contamination from mining activities is a major concern, yet driving mechanisms and health risk differences caused by spatiotemporal variability remain unclear. This study investigated a typical pyrite mining area in middle and upper reaches of the Yangtze River in China, collecting 354 shallow groundwater samples during the 2023 wet and dry seasons to assess driving factors and health risk of nine heavy metals (Fe, Mn, Cu, Zn, Hg, As, Cd, Pb, Se) at spatiotemporal variability. Results showed most heavy metal concentrations were significantly higher in the dry season. Fe had the highest average concentration (41.04 mg/L), and Hg showed the most intense fluctuations. This seasonal difference exhibited a clear distance-attenuation effect: dry-season enrichment was pronounced in near-mine zones (