Inhibition of Mercury Methylation by Iron Sulfides in an Anoxic Sediment

Inhibition of mercury (Hg) methylation by iron sulfides in anoxic sediment is investigated. The moisture content of wet iron sulfide (FeS) is determined by weight change after drying under nitrogen (N sub(2)) flow. The amendment of commercial iron sulfide (CIS) or synthesized (Syn)-FeS into sediment slurries can greatly inhibit the formation of methylmercury (MeHg) probably by the reduction of bioavailable neutral mercury complexes via formation of charged Hg(II)-polysulfide complexes. The effectiveness of the CIS indicates that other species of iron sulfides can also work effectively in the inhibition of Hg(II) methylation. The results show that the oxidation of FeS does not significantly reduce its effectiveness regarding the inhibition of Hg(II) methylation.