The increasing use of neodymium (Nd) in high-tech industries, particularly in electronics, renewable energy, and other advanced technologies, raises concerns about their accumulation in soils and potential long-term ecological impacts. As demand for these rare earth elements grows, understanding their environmental fate and behavior is crucial. This study assesses the bioavailability, ecotoxicological effects, and enzymatic responses in three soils with contrasting properties, each contaminated with varying concentrations of Nd, to provide a comprehensive understanding of their potential toxic or beneficial effects on soils and resident organisms. Additionally, it explores the biogeochemical cycles of these elements within the technosphere and their possible biological roles. The results will help to indicate if Nd, as a representative technology-critical element, is bioavailable, and therefore accessible for biological uptake. If so, we expect that high concentrations of these elements, due to increased use, could induce stress responses in soil organisms, potentially disrupting vital metabolic pathways and contributing to a decline in soil health. Our findings will help elucidate whether Nd, despite offering technological benefits, might present ecological challenges if its environmental footprint is left unmanaged. Overall, this study underscores the importance of understanding the behavior of Nd in soil systems—not only to mitigate its potential ecological risks but also to inform future guidelines for sustainable industrial use of these technology-critical elements.