Mercury in the environment: Biogeochemical transformation, ecological impacts, human risks, and remediation...

Mercury (Hg), a pervasive environmental pollutant, poses a significant threat to ecosystems and human health due to its complex biogeochemical transformations. Emitted from both natural sources and anthropogenic activities, Hg undergoes atmospheric transport, deposition, and intricate chemical conversions, including microbial methylation, which produces the highly toxic methylmercury (MeHg). This bioavailable form of Hg accumulates in aquatic food webs, leading to biomagnification and severe ecological consequences. The environmental fate of Hg is governed by dynamic interactions between abiotic and biotic factors, including redox conditions, microbial activity, and organic matter composition. Aquatic ecosystems, particularly wetlands and estuaries, serve as hotspots for Hg methylation, exacerbating the risk of bioaccumulation in fish and, consequently, human exposure through seafood consumption. Chronic Hg toxicity in humans is linked to neurodevelopmental disorders, cardiovascular diseases, and immunotoxicity, posing serious public health challenges. Addressing Hg contamination requires an integrated approach, combining advanced remediation strategies such as phytoremediation, bioremediation, sorbent-based technologies, and nano-engineered materials. Regulatory frameworks like the Minamata Convention play a crucial role in mitigating Hg emissions, but novel interdisciplinary solutions are imperative to reduce Hg persistence in the environment. This review explores the intricate pathways of Hg transformation, its cascading effects on biodiversity and human health, and cutting-edge remediation strategies. Understanding these complex dynamics is essential for developing sustainable mitigation measures, ensuring ecological balance, and safeguarding public health in the face of increasing environmental Hg burdens.