Waste Allocation Simulation Models: A State-of-the-Art Review (Journal Version)

摘要

The waste load allocation process for toxic chemicals requires a different approach than that used for conventional pollutants. Present waste load allocations for toxicants generally rely on simple dilution calculations for low stream flow conditions. The paper examines the new water quality criteria for toxicants and the modeling strategies used to implement the criteria. The new criteria specify an acute threshold concentration and a chronic-no-effect concentration for each toxicant as well as tolerable durations and frequencies of exposure at or above the two concentrations. Methods for using steady-state and dynamic models to derive waste load allocations based on the new criteria are reviewed. Physical, chemical, and biological processes affecting toxicants in the mixing zone and far-field regimes of streams are summarized.