Determination of natural uranium and thorium levels in environmental matrices surrounding uranium mining sites via ICP-MS

Abstract This study quantified natural uranium and thorium concentrations in environmental matrices surrounding a uranium mining area in Brazil and evaluated the distribution of uranium and thorium radionuclides in ores, waters, and soils from the Cachoeira and Engenho mines. Distinct geochemical signatures were observed between the mines, with lower uranium-to-thorium ratios at Engenho. While thorium levels in ores were lower than commonly reported, elevated concentrations in aqueous samples suggest strong geological and hydrological controls. Agricultural soils showed moderately enhanced thorium, indicating limited mining influence.