Guidance for Conducting Risk Assessments and Related Risk ...

• document the magnitude of risk and the primary causes of that risk, and
• define Remedial Goal Options (RGOs).
Note: During the preparation of the baseline human health risk assessment, newly acquired data will be
incorporated in the watershed database and the modified data set will again be compared to risk-based
PRGs. This comparison may result in the identification of early actions (including removals and interim
actions) in order to reduce risks and/or accelerate the clean-up process.
Figure 2
Scoping Workshop
Site Characterization
Establish Remedial
Goal Options (RGOs)
Figure 4
2.2.3 Feasibility Study
Early Action
(e.g. removal,
interim action
The Project Scoping Workshop and Risk Assessment
• compile existing data,
• develop a conceptual site model,
• develop risk-based PRGs and screen data to identify early,
actions and chemicals of potential concern,
• develop RI/FS data quality objectives,
• focus additional sampling and anlaysis efforts of chemicals of
potential concern, and
• provide justification for no further action.
Site Characterization and Risk Assessment
• help determine whether additional response action is necessary,
• provide evaluations of the effectiveness of actions (where appropriate),
• document the magnitude of risk and the primary causes of that risk, and
• define uncertainties.
No Further
Action
Remedial Goal Options and Risk Assessment
• incorporate results of baseline risk assessment,
• calculate RGOs for contaminants of concern by media, using site-specific exposure parameters, &
• identify ARARs.
Figure 3. Site characterization and risk assessment
The selection of an appropriate remedial action begins with a screening of potential alternatives
during the initial scoping workshop. This is conducted prior to the development of the RI work plan
(Fig. 4). The preliminary screening of alternatives is refined as more information becomes available and
the results of the baseline ecological and human health risk assessments determine the chemicals and
pathways of concern. During the selection of remedial actions, short-term and long-term risks must be
considered. The analysis of short-term risks focuses on the potential adverse effects on human health and
the environment from implementation of the remedial action. The analysis of long-term risks focuses on
the risk that will remain after remedial action has been taken (this level of remaining risk is termed
residual risk). These analyses may be either qualitative or quantitative, depending on site conditions. For
more information, refer to page 14 of Risk Assessment Guidance for Superfund, Part C (EPA 1991b).
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