A series of lab aeration experiments was conducted in batch reactors to investigate the effects of aeration of sediment on the sulfide content of sediment and on the partitioning of cadmium, a model toxic metal, to the sediment. Aeration of sediment results in rapid decrease of the AVS. We studied the sediment characteristics for aeration periods of approximately a month. During this time, the concentrations of dissolved metals increased by 200 to 400% or more, relative to the concentrations present at the beginning of the test. The concentrations of metals associated with AVS and with pyrite become increasingly more important in the binding of cadmium. Following the aeration, more than 50% of the cadmium was associated with the extractable iron and manganese components of the sediment. Overall, the binding capacity of the sediments for cadmium decreased after aeration.