A review of rare earth elements in waste disposal: Release mechanisms, environmental behaviors and risks
Zhunan Xiong, Shun Li, Siyu Wang, Jing Wang, Lingqing Wang, Tao Liang
Abstract
The extensive extraction and use of rare earth elements (REEs) have generated significant REE-containing waste. However, the release behaviors and migration pathways of REEs during waste disposal remain insufficiently explored. This study examines the four main categories of REE-containing waste—industrial, medical, electronic, and municipal solid waste (MSW)—providing a comprehensive analysis of their characteristics, disposal practices, and the mechanisms driving REE release and migration. Traditional waste management methods, such as landfilling and incineration, prove ineffective in recovering REE resources and cause release risks. Notably, gadolinium (Gd) anomalies from Gd-based contrast agents (GBCAs) have been detected in global water bodies, groundwater, and even drinking water. Incineration and e-waste dismantling elevate REE levels in soil and increase atmospheric concentrations in particulates and aerosols. Exogenous REEs pose ecological and toxicological risks, including bioaccumulation, oxidative stress, and metabolic disruption in animals, as well as dose-dependent effects on plant growth and nutrient uptake. Human health risks are particularly pronounced among workers in e-waste dismantling, with documented cases of anemia and hormonal imbalances. REEs from sources like GBCAs can enter the food chain via aquatic organisms, algae, and plants, leading to long-term human accumulation and associated health effects. This study emphasizes the need for improved recycling of REE-containing waste, better monitoring of impacts, and further research on REE ecotoxicology and bioavailability.