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Advancing the Ecological Assessment Process for Pesticides

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Why Revise the Assessment Process?

Provide Agency regulators with:

  1. Answers to risk management questions which could not be quantitatively addressed in the past, and

  2. Improved risk characterizations, focusing on magnitude, probability, and certainty of predictions.

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What Are The Risk Management Questions?

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How Did We Go About It?

Formed ECOFRAM (Ecological Committee on FIFRA Risk Assessment Methods), a stakeholder workgroup, in 1997.

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What Happened Next?

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What Does This Assessment Scheme Look Like?

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What About Moving Between the Levels?

Guidance will be developed for when to move to higher levels

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Where Are We Now?

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What Does The Aquatic Model Look Like?

Aquatic Organisms and Endpoints

Spatial Scale

Acute Risk

Chronic Risk

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What About the Aquatic Results for Acute Risk?

Screening Level I assessment provides an acute risk quotient of 0.83 for daphnia and 5.2 for pink shrimp. What does this mean? The Level II assessment provides estimates of acute risk in terms of magnitude and probability and uncertainty in the risk estimates can be included. On average the pesticide is expected to reach surface water concentrations that result in 11% mortality of an exposed Daphnia population, confidence limits 2 - 27% mortality. Infrequently (one year out of twenty, 95th percentile), Daphnia would be expected to incur ∼ 41% mortality (5 - 89%). Nineteen out of twenty years (5th percentile) the pesticide is expected to reach surface water concentrations that will result in 94% mortality of exposed pink shrimp, 95% confidence limits of 86 - 99% mortality.

ProbabilityDaphnia Pink Shrimp
5th percentile 2 (<1-7)94 (86-99)
Median 7 (1-22)98 (92-100)
Mean 11 (2-27)96 (89-98)
95th percentile 41 (5-89)100 (99-100)

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What Does the Terrestrial Model Look Like?

Effects Model

Uses distributions based on the dose/response curve to estimate and address


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What About the Terrestrial Results?

95% probability that red-wing mortality will be greater than 9 out of 20 individuals (45% mortality) There is a 5% probability that mortality will be greater than 80%.

cumulative probability graph of red-wing blackbird mortality

Red-Winged Blackbird Mortality

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What Do the Regulators Say About the Models and Results?

General Comments

Comments Related to Decision-making

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What Else Have We Been Doing?

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What Are the Next Steps?

Next Steps
  • Finish Level II models
  • Develop training materials
  • Hold training
  • Participate in peer review
  • Implementation

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OPP EFED Implementation Team


Ingrid Sunzenauer, M.S.

Aquatic Team

Donna Randall, M.S. (Lead)
Dirk Young, Ph.D.

Terrestrial Team

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

EFED Technology Teams

Other Team Members

Tim Barry, Sc.D. (Office of the Administrator)
Stephanie Irene, Ph.D.
Douglas Urban, M.S.

Former Team Members

Kathryn Gallagher, Ph.D.
Les Touart, Ph.D.
Jim Lin, Ph.D.

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