Introduction: Metals in Health and Environment

Abstract

Metals occupy a unique and often paradoxical position at the interface between human health and the environment. Essential metals such as iron, zinc, copper, magnesium, and molybdenum are indispensable for numerous biological processes, yet their deficiency or excess can lead to serious health consequences. In contrast, toxic metals including lead, mercury, cadmium, and arsenic can cause severe neurological, renal, cardiovascular, and carcinogenic effects, even at very low concentrations. Their persistence in the environment, together with bioaccumulation and biomagnification, further amplifies their impact on ecosystems and human populations. This introductory chapter presents the “good, the bad, and the ugly” of metals, providing an overview of their essential biological functions, toxicological effects, environmental contamination, and long-term ecological consequences. It also highlights recent advances in metal detection, quantification, remediation, and therapeutic intervention, including chemosensors, biosensors, nanotechnology, bioremediation, phytomining, chelation therapy, metallomics, gene editing, and artificial intelligence. Together, these approaches illustrate the need for an integrated and multidisciplinary strategy to maximize the beneficial roles of metals while minimizing their adverse effects on human health and the environment.