Fate of incorporated metals during mackinawite oxidation in sea water

Oxidation of mackinawite can occur at the water-sediment interface when anoxic sediment is disrupted into the oxic water column. During this process, pollutant metals and As that have become incorporated into the pyrite precursor could change oxidation states and become mobile in the water column. Mackinawite oxidation in aerated sea water was measured in laboratory experiments. Synthesized mackinawite oxidized readily with most sulfide reacting within 5 h when exposed to light and 8 h when kept in the dark. A batch of the synthetic mackinawite doped with several metals and As was then placed in filtered sea water and aerated. The filtrates and particulates were collected at various times to analyze both for trace metals and As. Most metals and As were found to remain in the particulate phase. But Cd was found to be unique as a measurable portion did partition into the filtrate.