Introduction to ModelMaker

Sabine Beulke, CSL, York, UK FOCUS Work Group on Degradation Kinetics

Estimating Persistence and Degradation Kinetics from Environmental Fate Studies in EU Registration

Brussels, 26-27 January 2005

Curve fitting with ModelMaker

100 80 60 40 20 0 DT50 DT90 Time 100 80 Parent Metabolite 60 40 20 0 0 20 40 60 80 100 120 140 160 Days after application

Model construction

Model components Compartment

Part of the system with defined boundaries which can store the quantity of interest (e.g. a pesticide) Parent in soil Metabolite in soil

Flow

Represents the movement of the quantity from one compartment to another

Change of quantity in compartment with time dCompartment / dt = + Flows in - Flows out

Parent  Metabolite

Variable

Quantity which is a function of other model components or a function of an independent variable (e.g. time) DT50 as a function of other model parameters

Initial conditions and parameters For each compartment, the starting point (quantity present at the beginning of the simulation) must be defined

Parent: 100% applied radioactivity Metabolite: zero

Parameters are constants which do not change during the simulation k parent degradation rate constant for the parent in soil M 0 initial amount of the parent compound ffM formation fraction

ModelMaker toolbar run model optimise model create graph create table add and define parameters compartment variable flow