A geo-referenced aquatic exposure prediction methodology for ‘down-the-drain’ chemicals1

Abstract

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, including their spatial and temporal variability and uncertainty. It results in statistical frequency distributions of predicted environmental concentrations (PEC). A hybrid stochastic/deterministic simulation approach is used. Steady-state deterministic models, which describe chemical 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 surface waters), and treatment (on-site treatment, waste water treatment plants). In the river model, chemical transport and conversion in main rivers is simulated.