Introduction

The Office of Environmental Policy and Assistance (EH-41) provides policy guidance and technical assistance on hazardous and mixed waste issues and environmental restoration at Department of Energy (DOE) facilities. CERCLA and RCRA programs require risk assessments to be conducted at many DOE sites to determine potential impacts to public health and the environment. In order to develop risk assessment data quality objectives (DQOs), observational approach decisions, and contaminant sampling design specifications, the environmental restoration project team frequently uses a Site Conceptual Exposure Model (SCEM).

The SCEM includes a visual presentation of site exposure conditions that relates the source of contamination to human and ecological receptors. Based on the SCEM, a data collection strategy is developed to prioritize field sampling activities and reduce uncertainty in risk characterization (e.g., contaminant release/transport mechanisms, receptor profiles, etc.). The SCEM also provides sufficient information to develop a strategy for early response actions to address exposure pathways that are considered complete and may pose an imminent risk to public health.

DOE environmental restoration program managers (ERPMs) need the ability to develop SCEMs that promptly generate a range of "what-if" scenarios to respond to questions regarding site exposure conditions and data collection programs. The SCEM Builder provides a friendly graphical environment that considerably shortens the time required to generate SCEM diagrams and associated documentation.