Global mercury pollution biogeochemical transformations, ecological consequences, human health risks, and remediation...

Mercury (Hg) is a persistent and highly toxic pollutant that poses significant threats to ecosystems and human health. Its long-range transport, bioaccumulation, biomagnification, and complex environmental cycling amplify these risks. This review provides a comprehensive overview of mercury's sources, transformations, impacts, health risks, remediation strategies, and regulatory frameworks. Mercury enters the environment from natural sources, such as volcanic eruptions, rock weathering, forest fires, and ocean emissions, as well as from anthropogenic sources, such as coal combustion, mining, industrial discharge, and waste incineration. After release, mercury undergoes various physical, chemical, and biological transformations, including the microbial conversion of inorganic mercury to methylmercury, its most toxic and bioaccumulative form. It accumulates in aquatic organisms and biomagnifies through food webs, causing reproductive toxicity, growth inhibition, behavioral changes, and biodiversity loss. Human exposure primarily occurs through consumption of contaminated fish or water, occupational activities, or inhalation of mercury vapor, leading to neurotoxicity, kidney damage, developmental disorders, and immune dysfunction. Remediation strategies, involving physical, chemical, biological, and nanotechnology-based approaches, aim to remove or immobilize mercury. Effective pollution control requires sustainable remediation, monitoring, stringent regulations, and international cooperation through agreements such as the Minamata Convention on Mercury.