Methodology used for a laboratory determination of relative contributions of water, sediment and food chain routes of uptake for 2,3,7,8-TCDD bioaccumulation by lake trout in Lake Ontario

A long-term laboratory exposure of lake trout to Lake Ontario sediment and smelt (food chain) provided comprehensive bioaccumulation relationships for 2,3,7,8-TCDD. The laboratory exposure was designed to investigate the rates of TCDD uptake via water, sediment, and food under simulated Lake Ontario conditions. Innovative methods of preparing sediment, dosing sediment, preparing food and feeding the fish were developed. Results indicated that bioaccumulation of 2,3,7,8-TCDD occurs primarily through the food chain and secondarily through contact with contaminated sediment. The water exposure route, even under simulated equilibrium conditions, and low suspended solids concentrations did not appear to make a significant contribution to 2,3,7,8-TCDD bioaccumulation.