Dr. F. Gobas
School of Resource and Environmental Management
Simon Fraser University
Burnaby British Colombia
Canada, V7K 1S6
Phone: +1 604-291-5928
Fax : +1 604-291-4968
EcoFate is designed to assess the cumulative impact of chemical inputs in terms of contaminant concentrations in water, sediment and biota of an entire ecosystem and to interpret these concentrations in terms of exceedance of environmental criteria and standards, potential for toxic effects in biota of the ecosystem and risks to human beings exposed to contaminated fish products or contaminated water.
EcoFate consists of a combination of an environmental fate, food-web bioaccumulation, toxicological hazard, and human health risk assessment model, which are integrated to directly relate chemical emissions to concentrations, toxic effects and human health risks. Each of the models is based on best available knowledge of the mechanisms of chemical distribution, toxicity and risk. The assessments can be done on a time-dependent and time-independent (i.e. steady-state) basis.
The model is based on the numerical solution of a set differential equations, each representing the flux of the chemical in each environmenal compartment as a function of the kinetic rate constants for chemical transport and transformation. Important parameters for using the model include (1) data regarding the configuration of the ecosystem (dimensions, flow, temperature, resuspension and sedimentation rates), (2) the weights, lipid contents and feeding preferences of aquatic organisms and (3) the octanol-water partition coefficient, the dissociation constant and the Henry's Law Constant of the chemical substance. The model contains various algorithms to derive feeding rates, gill ventilations rates in fish, uptake and elimination rate constants of organic chemicals in giota, volatilization rate constants, biovailability and others.
The main purpose of EcoFate is to investigate whether existing or planned chemical emissions can be expected to pose an ecological or human health risk, meet environmental quality standards or criteria and to identify the “assimilative capacity” of ecosystems for chemical substances in terms of maximum daily loadings.