A GEO-REFERENCED AQUATIC EXPOSURE PREDICTION METHODOLOGY FOR DOWN-THE-DRAIN CHEMICALS

A geo-referenced simulation methodology for the prediction of aquatic exposure to individual 'down-the-drain' chemicals (consumer chemicals which mainly enter the environment via the domestic waste water route, e.g. detergents) is presented. This method uses real-world data, incl uding their spatial and temporal variability and uncertainty. It resul ts in statistical frequency distributions of predicted environmental c oncentrations (PEG). A hybrid stochastic/deterministic simulation appr oach is used. Steady-state deterministic models, which describe chemic al fate, form the system's core. A stochastic (Monte Carlo) simulation is applied on top of this. In the (deterministic) waste water pathway model, all processes which occur in the waste water drainage area of a discharge point are considered: emission, transport (sewers, small s urface waters), and treatment (on-site treatment, waste water treatmen t plants). In the river model, chemical transport and conversion in ma in rivers is simulated. (C) 1997 IAWQ. Published by Elsevier Science L td.