Mercury in Municipal Sewage and Sewage Sludge.

Wide occurrence of mercury species, including the highly toxic and readily bioaccumulative methylmercury (MeHg), in municipal sewage (MS) and sewage sludge (SS) has been evidenced in recent studies. Considering that vast amounts of MS and SS are produced globally each year and the majority of MS is discharged into aqueous environments, i.e., the main sites for MeHg bioaccumulation, special attention should be paid on the source and environmental behaviors of sewage-borne and sludge-borne mercury species. This review aims to summarize the findings on the occurrence of mercury species in MS and SS, their transport and transformation in MS treatment plants, as well as their fate and environmental implications.