Introduction - Elements of Environmental Engineering: Thermodynamics and Kinetics - page 6

TABLE 1.2
Descriptions of a Few Multimedia Fate and Transport Models that are
Currently in Use
Model Acronym Description

CalTOX A fugacity-based model to assist the California Environmental Protection

Agency to estimate chemical fate and human exposure in the vicinity of
hazardous waste sites

ChemCAN A steady-state fugacity-based model developed for Health Canada to

predict a chemical's fate in any of the 24 regions of Canada

HAZCHEM A fugacity-based model developed as a regional scale model for the

European Union Member States

SimpleBOX Developed by RIVM, the Netherlands, it uses the classical concentration

concept to compute mass balances

Source: The multi-media fate model: A vital tool for predicting the fate of chemicals, SETAC Press,
1995.

from the groundwater aquifer. Indirect exposure results, for example, from ingestion
of contaminated fish from a lake that has received a pollutant discharge via the soil
pathway. Coupling the toxicology with a multimedia fate and transport model thus
provides a powerful tool to estimate the risk potential for both humans and the biota.
Risk assessment is typically divided into the assessment of cancer and noncancer
health effects. Animal toxicology studies or human epidemiological data are used to
establish a unit risk level for cancer.A dose-response model then relates the response
to the dosage to which the subjects are exposed. Most cancer dose-response models
conservatively assume a no-threshold model, so that the risk is extrapolated from high
to low dosages assuming that there is some response at any dosage above zero.

Air pathway

Source

Lake

Receptors

Soil pathway

Groundwater pathway

FIGURE 1.3 Environmental risks and exposure pathways.