Information on Hazardous Substance Releases Within the 1100 Area.

摘要

The Hanford 1100 Area National Priorities List (NPL) site (Figure 1) consists of four operable units (OU): 1100-EM-l, 1100-EM-2,1100-EM-3, and 1 lOO-IU-l. Each OU is designated with a three-part code: the first part indicates the NPL site affiliation; the second part describes the OU type (equipment maintenance [EM] and isolated unit [IU]); and the third part is the number specific to the OU. -The 1100 Area was listed on the NPL (54 FR 41015, Oct. 4,1989), based on the proximity of the 1100-EM-l, 1100-EM-2, and 1100-EM-3 OUs to groundwater wells that supply drinking water to the City of Richland (DOE-RL 1995b). The 1100-EM-l, 1100-EM-2, and 1100-EM-3 are located in the southern-most portion of the Hanford Site; these OUs contain the central warehousing, vehicle maintenance, and transportation distribution center for the entire Hanford Site. The 1100-IU-l is located within the Fitzner-Eberhardt Arid Lands Ecology Reserve (ALE) on the northeastern slope of Rattlesnake Mountain, approximately 24 km west of the 1100 Area (EPA 1993). The closest surface water bodies to the 1100 Area are the Columbia and Yakima Rivers. These rivers are approximately 1,200 and 6,500 m, respectively, from the 1100 Area. Available floodplain information indicates that the 1100-EM-2,1100-EM-3, and 1100-IU-l are not located within the limits of the Columbia and Yakima River flood plains (DOE-RL 1992c). The 1100-EM-l was designated the highest priority among the Hanford Site 1100 Area OUs because of the potential for contamination at the Antifreeze Tank Site and the Battery Acid Pit and their proximity to the North Richland well field. Remedial Investigation/ Feasibility Study (RI/FS) activities at the 1100-EM-l were initiated in 1989, and a Phase I REFS was completed in August 1990. A baseline risk assessment was conducted as part of the RI/FS to evaluate current and potential effects of the 1100-EM-l contaminants on human health and the environment (DOE-RL 1992b). In the fall of 1992, the U.S. Environmental Protection Agency (EPA), U.S. Department of Energy, Richland Operations Office (RL), and the Washington State Department of Ecology (Ecology) accelerated the study and. evaluation of the three other OUs so that all remedial actions in the 1100 Area could proceed as a single project.