This report provides an interpretation of analytical results for dioxins and furans in water, biofilm, sediment, invertebrates, and fish samples collected on the Athabasca and Peace Rivers in 1992. The analysis focused on the partitioning, fate, and bioaccumulation of the two compounds having the greatest potential to accumulate in animal tissue, namely 2,3,7,8-tetrachloro dibenzo-p-dioxin and 2,3,7,8-tetrachloro dibenzofuran, in order to assist in the assessment of ecosystem health and long-term effects. The report compares the levels of these compounds found upstream and downstream from pulp and paper mills, and compares the detected levels to the limits recommended under the Canadian Environmental Quality Guidelines (for sediment and water) and Health Canada guidelines (for fish tissue).