A risk assessment tool to provide predictive modeling spatially and temporally to assess changes in the contaminant concentrations of aquatic organisms over time following remedial actions or other management alternatives at sediment sites. Improves the predictive capacity associated with spatially-explicit bioaccumulation models during risk assessments. Specifically, simulates fish foraging behavior over GIS-defined spatially-variable sediment and water exposure concentrations using a dynamic (time-varying) mathematical framework; allows direct linkages to ecological assessments of impacts to fish populations; supports risk assessments for fish consumers (either human or ecological) or direct risks to fish; allows users to control spatial patterns of contaminant concentrations (e.g., through remediation alternatives, maintenance dredging, and so on).