Preface: Heavy metal(loid)s at mining & metallurgical sites: Fate, risk and remediation

The contamination of heavy metal(loid)s at mining & metallurgical sites has been a major environmental challenge worldwide [1].Typically, large amounts of metal(loid)s-bearing wastes are generated at these sites, such as smelting slag, combustion residues, mine tailings, wastewater, and exhaust gas [2].Due to their high mobility in the environment, the released heavy metal(loid)s can easily enter the soil and water environment, posing long-term and widespread threats to ecological and human health [3].In addition to active mining and smelting sites, there has been a substantial increase in abandoned contaminated sites in the last several decades due to rapid industrialization and mounting environmental regulations, which need to be remediated urgently.Numerous studies have shown that soil and groundwater around smelting sites are heavily contaminated with heavy metal(loid)s, with common contaminants including lead, Znic, arsenic, cadmium, chromium, copper, mercury, and nickel [4,5].To mitigate the environmental and health impacts, great efforts have been devoted to the research and development of cost-effective remediation technologies.Typically, remediation strategies have been categorized into physical, chemical, and biological approaches as well as combinations thereof [6].