Environmental Analysis Tools - Environmental Impact Analysis: Process and Methods - page 266

Initial problem formulation
including ecological endpoints

Risk but extent
uncertain

Screening level exposure estimate and risk
characterization

Signif icant and
extensive risk

Revised & detailed problem
formulation

No elevated
risk

Detailed ecological investigation
design and implementation

Exposure
characterization

Efects
characterization

Risk
characterization

Input to remediation decisions

FIGURE 7.1
An ecological risk assessment process summary. ( Adapted from U.S. EPA. 1997. Ecological
risk assessment guidance for Superfund: Process for designing and conducting ecological risk
assessments: EPA 540-R-97-006; U.S. EPA. 1998. Guidelines for Ecological Risk Assessment: EPA
630-R-95-002F; Maughan, J.T. 1993. Ecological Assessment of Hazardous Waste Sites . New York:
Van Nostrand Reinhold.)

Determine
stress levels
causing effects

Develop
conceptual
model

Risk
characterization

Determine
exposure
levels

Stressor
Pathway

Receptor

FIGURE 7.2
A simplified ecological risk assessment process.