Development of a cumulative risk assessment for the Idaho National Engineering Laboratory`s waste area group 2

In 1989, the Idaho National Engineering Laboratory (INEL) was added to the Environmental Protection Agency`s (EPA) National Priorities List of Superfund sites. A Federal Facility Agreement and Consent Order (FFA/CO) for the INEL was signed by the Department of Energy, Idaho Operations Office (DOE-ID), EPA, and the State of Idaho in December 1991. The goal of this agreement is to ensure that potential or actual INEL releases of hazardous substances to the environment are thoroughly investigated in accordance with the National Contingency Plan (NCP) and that appropriate response actions are taken as necessary to protect human health and the environment. The Test Reactor Area (TRA) is included as Waste Area Group (WAG) 2 of ten INEL WAGs identified in the FFA/CO. WAG 2 consists of 13 operable units (OUs) which include pits, tanks, rubble piles, ponds, cooling towers, wells, french drains, perched water and spill areas. OU 2-13 is the Comprehensive Remedial Investigation/Feasibility Study (RI/FS) for WAG 2. The study presented here is a preliminary evaluation of the comprehensive risk for WAG-2. This investigation will be used as the basis of the WAG-2 comprehensive baseline risk assessment (BRA), and it will serve as a model for other INEL comprehensive risk assessments. The WAG-2 preliminary risk evaluation consisted of two broad phases. These phases were (1) a site and contaminant screening that was intended to support the identification of COPCs and risk assessment data gaps, and (2) an exposure pathway analysis that evaluated the comprehensive human health risks associated with WAG-2. The primary purposes of the investigation were to screen WAG-2 release sites and contaminants, and to identify risk assessment data gaps, so the investigation will be referred to as the WAG-2 Screening and Data Gap Analysis (SDGA) for the remainder of this report