| Abstract
| - The stability of metal sulfides to oxidation in seawaterwas investigated in short-term (24 h) resuspensionexperiments using natural sediments and synthetic metalsulfide phases. Using acid volatile sulfide (AVS) measurements, ZnS, PbS, and CdS phases were shown to beresistant to oxidation. The AVS in resuspended, highlyanoxic, contaminated sediments was rapidly oxidized with<6% remaining after 24 h. This was inconsistent withtheir high particulate lead and zinc content, which shouldstabilize sulfide against oxidation, suggesting that alarge proportion of these metals (73−95%) were nonsulfidephases. When zinc was added to the sediments in asoluble ionic form, ZnS was quantitatively formed; however,lead and zinc solid phases, equilibrated with the sedimentsfor several months, exhibited varying degrees of sulfideformation (10−76%). The results were consistent with therapid formation of metal sulfide coatings that armor theparticles against further sulfidization. It appears that reactivesulfide phases play a limited role in controlling thespeciation of many metals entering sulfide-rich sedimentaryenvironments. The initial form of the metals may be ofgreater importance.
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