Introduction to ModelMakerIntroduction 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 ModelMakerCurve fitting with ModelMaker

0

20

40

60

80

100

Time

Co

nce

ntra

tion

(%)

DT50 DT90

0

20

40

60

80

100

0 20 40 60 80 100 120 140 160

Days after application

% o

f app

lied

radi

oact

ivity

Parent Metabolite

Model constructionModel construction

Compartment

Flow

Model componentsModel components

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

Represents the movement of the quantity from one compartment to another

Parent in soil

Metabolite in soil

Parent Metabolite

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

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

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 changeduring the simulation

kparent degradation rate constant for the parent in soil

M0 initial amount of the parent compound

ffM formation fraction

Initial conditions and parametersInitial conditions and parameters

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compartment flow

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