# ECOFRAM: Aquatic Risk Assessment

Jeffrey Giddings

Springborn Laboratories Inc.

Paul Hendley

Zeneca Ag Products.

**On this Page**

- Risk Quotient Equation
- Probabilistic Risk Characterization
- Exposure Distribution
- Exposure Analysis
- Probability of Exceeding LC50
- Probability of Mortality
- Extrapolation to Population Effect
- Another Endpoint: the PR50
- Probability of Population Decline
- Distribution of Species Sensitivity
- Probability of Affecting Species
- Pulsed Exposure
- Assessing Effects of Pulsed Exposures
- Other Components of Effects Analysis
- Outstanding Issues
- Summary of Tools for Effects Assessment
- Risk Assessment Process

## Risk Quotient = Exposure Concentration / Effect Concentration

## Probabilistic Risk Characterization

## Exposure Distribution

## Exposure Analysis

*Step 1:*Deterministic; edge of field/pond, worst case (GENEEC)*Step 2:*Probabilistic; more chemical information; variation with weather, region, receiving water type (PRZM/EXAMS)*Step 3:*Probabilistic; landscape and watershed factors

## Probability of Exceeding LC50

## Probability of Mortality

## Extrapolation to Population Effect

## Another Endpoint: the PR50

## Probability of Population Decline

## Distribution of Species Sensitivity

## Probability of Affecting Species

## Pulsed Exposure

## Assessing Effects of Pulsed Exposures

Time-to-event analysis

Laboratory toxicity tests simulating simplified pulses

Uptake / depuration models linked to critical body residue data

## Other Components of Effects Analysis

Chronic toxicity

Reproductive effects

Sediment exposure

Behavioral endpoints

## Outstanding Issues

Overall ecosystem damage

extrapolation from populations to ecosystems

microcosms and mesocosms provide insight

Mixtures, multiple stressors

## Summary of Tools for Effects Assessment

Time-to-Event Analysis

Pulsed Exposures

Population Models

Sensitivity Distributions

Sediment Toxicity Evaluation

Chronic Toxicity Tests

Mesocosms and Microcosms

Behavioral Toxicity Tests