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Evolution of OPP's Terrestrial Investigation Model
Software and Programming to Meet Technical/Regulatory Challenges

Edward Odenkirchen, Ph.D.
Environmental Fate and Effects Division
Office of Pesticide Programs
USEPA

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Background : Terrestrial Investigation Model (TIM 1.0)

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TIM 1.0: Why Excel and Crystal Ball?

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2001 SAP Recommendations

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The complex was to get even more complex . . .

flow diagram of inputs and processes in the conceptual model with additions highlighted between old and new

The complex was to get even more complex . . .

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Changes for New Model

Model Component TIM 1.0 TIM 2.0
Drinking water Mean daily value from PRZM and variance from field data on puddles Model of field puddles
Monte Carlo
Inhalation None Vapor and droplet phase;
potency factor
Dermal None Direct deposition and incidental contact with foliage; potency factor
Use of treatment area over daily activity Set once / individual; even distribution of feeding activity Hourly Time Steps with Monte Carlo sampling; bimodal distribution of activity
Repetition of daily activity pattern Constant Markov chain
Tolerance level Probability of death interpolated for individual modeled dose Tolerance set for individuals, time to death (if any) tracked

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Model Changes and Their Effects on TIM 1.0 Environment

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Selecting a New Programming Environment: Criteria

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Approach Taken for TIM 2.0

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TIM 2.0

graphic depicting processes of user input, model calculations and graphical outputs

TIM 2.0

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The TIM 2.0 User Interface

computer interface screen; enter data step highlighted

The TIM 2.0 User Interface

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Application Method and Rate and Site Properties

computer interface screen; application method and rate along with site properties are highlighted

Application Method and Rate and Site Properties

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Chemical Properties

computer interface screen;  chemical properties highlighted

Chemical Properties

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Exposure Parameters

computer interface screen;  inhalation and dermal exposure parameters highlighted

Exposure Parameters

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Puddle Parameters and Generic Species Selection

computer interface screen; rainfall and generic species selection are highlighted

Puddle Parameters and Generic Species Selection

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Toxicological Data

computer interface screen;  toxicological data  highlighted

Toxicological Data

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Run Model and Display Results

computer interface screen;  highlights on buttons to run model and display results

Run Model and Display Results

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Excel Interface Options

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Excel Input and C-core Program Flexibility

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Excel Input and C-core Program Limitations

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Next Steps

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Web Site

http://www.epa.gov/pesticides/ecosystem/index.htm

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EPA Implementation Team

Chair
Ingrid Sunzenauer, M.S.

Aquatic Team
Donna Randall, M.S. (Lead)

Terrestrial Team
Ed Fite, M.S. (Lead)
Ed Odenkirchen, Ph.D.

Additional Supporting Team Members
Tim Barry, Sc.D. (EPA Office of the Administrator)
Dirk Young, Ph.D.
Douglas Urban, M.S.
Stephanie Irene, Ph.D.

Former Team Members
Kathryn Gallagher, Ph.D. (Former Lead, Aquatics)

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