Conceptual Site Model - Argonne National Laboratory

WVDP Phase 1 CSAPA.4.3.4Process Building SpillsPotentially Affected Media:Potentially Affected WMAs:surface soil, subsurface soil, groundwater1, 2, 3, 4, 5, 6 (North Plateau Groundwater Plume)Additional spills and other forms of less significant releases were likely to have occurred in theimmediate vicinity of the Process Building. An example of these includes Resin Pit spills in thearea east of the Fuel Receiving and Storage Building. These spills were associated withmaintenance of the spent nuclear fuel pool water filtration system (DOE 2009 Table 2-17). Thesereleases likely have contributed to the North Plateau Groundwater Plume.A.4.3.5Sewage Treatment System ContaminationPotentially Affected Media:Potentially Affected WMAs:subsurface soil, groundwater, sediment1, 6, 12 South (Erdman Brook)Historically, the Process Building was connected to the Old Sewage Treatment Plant (in WMA 6)via an underground wastewater line. A 1970 to 1971 investigation of unexpected tritium andgross beta contamination in Erdman Brook led to the discovery of contamination in the sanitarysewer system. It was discovered that the underground wastewater line had failed near thesouthwest side of the Process Building. The resultant leak allowed contaminated groundwater inthe area to enter the Old Sewage Treatment Plant. An estimated 0.5 Ci gross beta and 0.05 Ci ofSr-90 was released. The Old Sewage Treatment Plant and its outfall drainage were contaminatedto 1 mR/h, with effluent concentrations subsiding after the leak was repaired. Affected outfallswere located in WMA 6 with eventual discharge to Erdman Brook (in WMA 12 South)(DOE 2009 Table 2-17; DOE 2010 Section 3.11.5).In addition, during the 1960s and 1970s, the Old Sewage Treatment Plant experienced severalcontamination events, some of which were expressed as radioactivity increases in the treatedeffluent. The Old Sewage Treatment Plant outfall drainage extends approximately 650 feet southof a culvert near the Old Warehouse (also in WMA 6), and flows into the first culvert under therailroad tracks on the South Plateau (in WMA 6), and then to Erdman Brook (in WMA 6 andWMA 12 South).Rev. 1 A-7