Approximately 325 million cu m of sediment are dredged annually for navigation purposes in the United States. Of this, 46 million cu m are disposed of annually in the ocean. Decisions regarding the ocean disposal of dredged material result, in large part, from bioassessment-based estimates of contaminant exposure and ecological impacts. Predictions of impacts for an individual dredging project are estimated from laboratory determinations of the magnitude, bioavailability, bioaccumulation, and hazards (toxicity) of dredged material contaminants. Disposal site management of individual and multiple dredging projects requires monitoring for contaminant transport, availability and accumulation in biota, and the hazards to ecologically and commercially important populations. Because of their importance, suites of bioassessment methods representing several levels of biological organization have been proposed for predicting and assessing the hazards resulting from the ocean disposal of dredged material.