Vol. 5, Issue 2, Part A (2023)

Exposure to heavy metals continues to be a major global health concern, affecting biological systems in ways that go well beyond short-term toxicity. According to recent studies, metals like lead, cadmium, arsenic, and mercury leave long-lasting "epigenetic footprints" on the genome, changing chromatin structure, histone modifications, DNA methylation, and non-coding RNA activity. These disturbances, which ultimately change gene expression and disease vulnerability over the lifespan, are intimately linked to oxidative stress, compromised one-carbon metabolism, mitochondrial instability, and modified cellular signalling. In order to understand how heavy metals alter the epigenome and assess the consequences for human health, this paper summarises mechanistic, experimental, and population-level data. Additionally, it tackles methodological issues such as batch effects, cell-type heterogeneity, and obstacles in demonstrating causality that hamper the interpretation of epigenetic data. The article concludes by discussing how exposure assessment, public health surveillance, and environmental justice programs may benefit from epigenetic insights, providing avenues for more effective and equitable preventive measures.