Dredging operations technical support program: Summary of a workshop on interpreting bioaccumulation data collected during regulatory evaluations of dredged material

Dredged material disposal contributes significantly to contaminant bioaccumulation. However, it is costly and difficult to test bioaccumulation. Regulatory guidance uses two approaches for bioaccumulation testing. The first involves comparing the level of bioaccumulation of a contaminant to a numerical effect limit. When the level of the contaminant exceeds the numerical limit, the contaminant is stated to have an unacceptable adverse effect. The second method compares animals exposed to a reference sediment to the animal exposed to the contaminant. If bioaccumulation in the exposed animals exceeds that of the reference animals, then further testing is performed on subjective factors. This subjective data cannot be applied to the decision-making process. Because of this interpretation problem, a workshop was held in order to discover more effective regulatory guidance.