Artisanal mining of monazite and cassiterite in the Amazon: Potential risks of rare earth elements for the environment and human health

Abstract

Abstract A artisanal mining is applied on a large scale in developing countries, and in the Amazon region, the scenario is no different. This method of mineral exploration generally does not employ mitigation techniques for potential damages and can lead to various environmental problems and risks to human health. The objectives of this study were to quantify the concentrations of Rare Earth Elements (REEs) and estimate the environmental and human health risks in artisanal mining areas for cassiterite and monazite in the Amazon region, as well as to understand the dynamics of this risk over time after exploitation. A total of 32 samples of waste classified as sterile and mining reject in active areas, as well as in areas deactivated for one and ten years, were collected. Soil samples were also collected in a forest area considered as a reference site. The concentrations of REEs were quantified using alkaline fusion and ICP-MS. The results were used to calculate pollution indices and environmental and human health risks. REEs showed higher concentrations in anthropized areas. Pollution and environmental risk levels were higher in areas deactivated for one year, with considerable contamination factors for Gd and Sm and significant to extreme enrichment factors for Sc. Human health risks were low in all studied areas. The results indicate that artisanal mining of cassiterite and monazite has the potential for contamination and enrichment by REEs.