Contaminant Models for Surface Water

CE-QUAL-ICM is typically applied for conventional water quality issues such as eutrophication. A companion version, referred to as ICM/TOXI, has been developed for simulating transport and fate of contaminants such as organic chemicals and trace metals. ICM/TOXI models particulate and dissolved chemicals in the water column and bottom sediments, thus providing chemical exposure concentrations necessary for risk assessment. The toxicant routines for this model were obtained from EPA's WASP model. ICM/TOXI can be applied in a multi-dimensional fashion and requires externally supplied hydrodynamics like CE-QUAL-ICM. ICM/TOXI will be released to the public sometime in 1997.

A PC-based screening-level contaminant fate model, RECOVERY, is available for estimating long-term chemical concentrations in surface waters and their bottom sediments resulting from contaminant loadings and/or contaminated sediments. RECOVERY is a user-friendly, interactive PC model that can be rapidly applied with minimum input data requirements. The physical representation of a system by RECOVERY consists of a well-mixed (zero-dimensional) water column underlain by a vertically stratified sediment column consisting of multiple layers. The model allows the user to rapidly evaluate recovery scenarios for contaminated sediments and to test various response actions, such as capping with clean sediments.

The PREWet model, which is discussed under the page "Wetland Water Quality Models," can also be used to estimate the removal of contaminants (organic chemicals and trace metals) by wetlands or other surface water. PREWet is an analytical, screening-level model with the assumptions of steady-state conditions and either a fully mixed water column or one-dimensional, longitudinally varying concentrations. The sediment bed is treated as a single compartment.