Artisanal mining is intensely carried out in developing countries, including Brazil and especially in the Amazon. 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 cassiterite and monazite artisanal mining areas in the southeastern Amazon, as well as to understand the dynamics of this risk over time after exploitation. A total of 35 samples of wastes classified as overburden and tailings in active areas, as well as in areas deactivated for one and ten years were collected. 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 (< 1) in all studied areas. The results indicate that artisanal mining of cassiterite and monazite has the potential to promote contamination and enrichment by REEs.

Perovskite solar cells (PSCs) are emerging photovoltaic (PV) technologies capable of matching power conversion efficiencies (PCEs) of current PV technologies in the market at lower manufacturing costs, making perovskite solar modules (PSMs) cost competitive if manufactured at scale and perform with minimal degradation. PSCs with the highest PCEs, to date, are lead halide perovskites. Lead presents potential environmental and human health risks if PSMs are to be commercialized, as the lead in PSMs are more soluble in water compared to other PV technologies. Therefore, prior to commercialization of PSMs, it is important to highlight, identify, and establish the potential environmental and human health risks of PSMs as well as develop methods for assessing the potential risks. Here, we identify and discuss a variety of international standards, U.S. regulations, and permits applicable to PSM deployment that relate to the potential environmental and human health risks associated with PSMs. The potential risks for lead and other hazardous material exposures to humans and the environment are outlined which include water quality, air quality, human health, wildlife, land use, and soil contamination, followed by examples of how developers of other PV technologies have navigated human health and environmental risks previously. Potential experimentation, methodology, and research efforts are proposed to elucidate and characterize potential lead leaching risks and concerns pertaining to fires, in-field module damage, and sampling and leach testing of PSMs at end of life. Lastly, lower technology readiness level solutions to mitigate lead leaching, currently being explored for PSMs, are discussed. PSMs have the potential to become a cost competitive PV technology for the solar industry and taking steps toward understanding, identifying, and creating solutions to mitigate potential environmental and human health risks will aid in improving their commercial viability.