Sources, pathways, and environmental impacts of heavy metal contamination in aquatic systems: a comprehensive review

Abstract

Heavy metal contamination in aquatic environments has emerged as a critical environmental concern due to its persistence, toxicity, and bioaccumulative potential. This review comprehensively examines the sources, pathways, and environmental impacts of heavy metals in aquatic systems. Both natural sources, such as weathering of rocks, volcanic eruptions, and geothermal activities, and anthropogenic sources, including industrial effluents, agricultural runoff, mining activities, urban discharge, and atmospheric deposition, are explored. The complex pathways of metal transfer involving water-sediment interactions, bioaccumulation in aquatic organisms, and metal transport through food chains are discussed, with emphasis on the dynamic interplay between environmental conditions and metal speciation. The environmental consequences of heavy metal contamination, such as water quality degradation, sediment toxicity, impacts on aquatic life, and associated human health risks, are highlighted. Case studies from various regions, including the Niger Delta in Nigeria, Yangtze River in China, and the Great Lakes in the USA, illustrate the global scale of the problem. This review underscores the urgent need for effective pollution control measures, regulatory frameworks, and remediation strategies to safeguard aquatic ecosystems and public health