Heavy Metals – Definition, Natural and Anthropogenic Sources of Releasing into Ecosystems, Toxicity, and Removal Methods – An Overview Study

The constant discharge of large quantities of toxic substances due to human activities has led to a global environmental issue. Numerous industrial sectors’ effluents, which include coal-based power plants, mineral extraction activities, electroplating processes, as well as battery manufacturing, release metallic ions towards different ecosystems, such as Cadmium (Cd), Mercury (Hg), and Chromium (Cr). Heavy metals pose a significant danger to living organisms, humans, and environments because of their properties, mainly severe toxicity, and strong accumulation ability. Metallic ions are not subject to breakdown towards final components when contrasted with organic contaminants, which are significantly impacted by biochemical and chemical decomposition. Consequently, eliminating these elements has been regarded as a significant task within the water treatment sector. The purpose of this article is to analyze the literature related to heavy metals in terms of different issues. The heavy metals expression is explained. The natural sources and human activities responsible for releasing metallic ions into the environment are comprehensively discussed. In addition, heavy metals toxicity and potential risks to humans and different ecosystems are included. Various approaches for removing heavy metals from industrial wastewater, along with their associated advantages and drawbacks, are further evaluated.