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9722-9FB - Investigations of Hazardous Waste at Hanford CERCLA Sites
Problem - The U.S. Department of Energy's (USDOE) Hanford Nuclear Reservation was designed and operated to produce plutonium for nuclear weapons. As a result of plutonium processing, and operation of 9 nuclear reactors, large volumes of liquid wastes have been generated and discharged to the ground. These wastes include a wide variety of radionuclides, organic, and inorganic chemicals contained in over 1,400 waste storage, disposal, and overspill sites. The USDOE operates a long-term ground-water monitoring program for selected radionuclide and inorganic constituents, and sampling has detected hazardous constituents in excess of EPA (U.S. Environmental Protection Agency) maximum contaminant levels. The Hanford site has been organized to 78 operable units, and the cleanup of each unit entails a detailed site characterization study to determine the nature and extent of contamination. EPA has oversight responsibility for the remediation and has requested the USGS to provide technical assistance.
Objectives - The objective of the work is to technically review and evaluate various USDOE work plans, data collection activities, and interpretive reports related to the hydrology, geology. and ecology at Hanford CERCLA (Comprehensive Environmental Response Compensation and Liability Act) sites.
Relevance and Benefits - The USGS provides technical assistance to EPA-Hanford in the form of document reviews and interpretations of technical issues. This arrangement provides EPA with access to the USGS' wealth of technical knowledge of the geology and hydrology of the Hanford Site and surrounding areas. It also provides EPA with unbiased technical advise on critical issues related to their regulatory decisions at Hanford.
Approach - As requested by EPA, the USGS will participate in planning meetings with representatives of the EPA, USDOE, and their contractors to discuss scientific approaches for addressing site characterization and ecological risk assessment needs. The USGS will review and comment on technical documents related to characterization and remediation, concentrating on sections pertaining to geologic and hydrologic characterization and ecological risk. The USGS will meet with representatives of the EPA, USDOE, and their contractors to discuss and resolve disputes on the technical approach and execution of the investigations. The USGS will provide technical assistance related to issues of site-wide modeling, and other activities as requested by EPA.
WA348 - Estimation of Natural Recharge at the Hanford Nuclear Reservation Using a Chloride Mass Balance and Chlorine 36 Isopotic Tracer - Completed FY1995
Problem - The USGS is conducting a hydrologic investigation of natural recharge at the Hanford Nuclear Reservation using chloride mass balance and chlorine 36 isotopic tracer techniques. To date, we have successfully measured the chloride and moisture content of ten soil profiles. Four profiles are from fine-grained soils with a grass and deep-rooted sagebrush vegetative cover, and six profiles are from sand and gravel soils with deep-rooted sagebrush. Samples from an additional three profiles from sandy soils with shallow-rooted grasses are presently being analyzed in the laboratory. The chloride mass balance from these soil cores has confirmed the study hypotheses that recharge is variable under differing soil and vegetation associations. To date, extracts of chloride have been collected from two of the fine-grained profiles and these extracts have been sent to the laboratory for analysis of 36 Cl. No chloride extracts have been collected from the coarse-grained sediment profiles. Chloride is extracted from only the fine-grained fraction of the cores, and the analyses of the chloride content and particle-size distribution revealed that the chloride content of these cores was insufficient to provide an adequate amount of extractable chloride for 36 Cl analyses. Therefore additional cores will need to be collected for analyses of 36 Cl in coarse-grained soils.
Objectives - The objective of the tracer study in FY 1992 is to finalize recharge estimates for the targeted areas of the Hanford site.
Approach - Two sil cores will be collected in areas on the Hanford site with coarse soils during the first quarter of FY 1992. One core will be collected north of 200 West Area from a sandy-gravelly soil with mature deep-rooted sagebrush and an anticipated depth to water of about 200 ft. The second core will be collected at the grass site from a uniform sandy soil with shallow-rooted grasses and an anticipated depth to water of about 40-50 ft. The particle-size distribution and chloride content data previously measured during the first phase of sampling will be used to determine the volume of material to be collected from each of these cores. The moisture and chloride content of the soil profiles will be measured and chloride will be extracted from discrete intervals in each soil core. Approximately ten extracts from the grass site profile and 15 extracts from the 200 West Area profile will be reserved to fill in data gaps that may result from the first round of 36 Cl analyses. The results of the 36 Cl analyses will be used to calculate the ratio of chloride input derived from wet fall and dry fall to finalize the calculation of recharge from the chloride mass balance. The 36 Cl analyses will also provide an independent estimate of recharge, and the recharge estimates from both of these methods will be compared to recharge measured from the Hanford site lysimeters.
WA282 - Basalt Waste Isolation Coordination - Completed FY1990
Problem - The Nuclear Regulatory Commission (NRC) is concerned about the potential shortcomings in the Site Characterization Report presently being prepared by Rockwell-Hanford Operations for evaluating the feasibility of burying high-level nuclear waste at the Hanford Reservation. The Nuclear Regulatory Commission believes that the hydrologic investigative work conducted by Rockwell needs more interaction with Battelle Pacific NW Laboratory and the U.S. Geological Survey (USGS). Rockwell's interpretation of the groundwater flow system varies significantly from views held by both Battelle and the Survey.
Objectives - To determine those differences that exist between Rockwell-Hanford Operations, Battelle Pacific NW Laboratory, and the Geological Survey concerning conceptualization and modeling of the groundwater flow system of the Columbia Plateau and the Pasco basin, and to attempt to resolve those differences.
Approach - The USGS shall participate with the other concerned parties in a task force whose purpose is to resolve differences in the conceptualization and definition of the groundwater flow system of the Pasco basin, and carry out computer and laboratory analyses and related studies as necessary for a complete analysis of the problem areas.