Remediation of mercury-contaminated soils and sediments using biochar: a critical review

Abstract The transformation of mercury (Hg) into the more toxic and bioaccumulative form methylmercury (MeHg) in soils sediments can lead to biomagnification MeHg through food chain, which poses ecological health risks. In last decade, biochar application, an situ remediation technique, has been shown be effective mitigating risks from Hg sediments. However, uncertainties associated with use its underlying mechanisms remain. Here, we summarize recent studies on effects advantages amendment related biogeochemistry bioavailability systematically analyze progress made understanding responsible for reductions bioaccumulation. existing literature indicates (1) that application decreases mobility inorganic (2) reduce accumulation crops but a complex effect net production. this review, two main mechanisms, direct mechanism (e.g., Hg-biochar binding) indirect biochar-impacted sulfur cycling thus Hg-soil binding), explain reduction by based interactions among biochar, soil under redox conditions are highlighted. Furthermore, problems treat Hg-contaminated sediments, such as appropriate dose long-term effectiveness discussed. Further research involving laboratory tests field applications is necessary obtain mechanistic role reducing diverse types varying develop completely green sustainable biochar-based functional materials Hg-related