Post-Closure Monitoring Report for Corrective Action Unit 342: Area 23 Mercury Fire Training Pit, Nevada Test Site, Nevada, Calendar Years 2000-2001
This biennial soil gas monitoring report provides an analysis and summary of site inspections and soil gas monitoring data obtained at the Area 23 Mercury Fire Training Pit site, located in Area 23 of the Nevada Test Site, Nye County, Nevada, during the calendar years December 1999--December 2001 monitoring period. This site is identified in the Federal Facility Agreement and Consent Order (FFACO, 1996) as Corrective Action Site (CAS) 23-56-01 and is the only CAS assigned to Corrective Action Unit 342. Inspections of the Area 23 Mercury Fire Training pit site are conducted to determine and document the physical condition of the site, monitoring well, and any unusual conditions that could impact the proper operation of the unit closure. Physical inspections of the closure were completed semiannually and indicated that the site is in good condition with no significant findings noted. The objective of the soil gas monitoring program is to determine if the remaining petroleum hydrocarbons beneath the above-ground storage tank area are undergoing natural biodegradation. Comparing initial conditions to those of the first biennial soil gas monitoring event indicate a general increase in concentration of organic analytes, although this trend is not strong. There has been a decrease in the amount of carbon dioxide, with the percentage of nitrogen and oxygen about the same. The increase in organic analytes indicates that mixing of the atmosphere with the air in the monitoring well is occurring. Changes in atmospheric pressure will drive air both in and out of the monitoring well. The change in carbon dioxide in the opposite direction possibly indicates a change in biological parameters between the sampling events. The sampling and analysis of future samples should be consistent with the methods already used. This includes sampling at the same time of year, but not immediately after a significant meteorological event. This means the results to date are not conclusive. Monitoring needs to be continued to make an effective evaluation.
- Research Organization:
- Bechtel Nevada Corporation (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC08-96NV11718
- OSTI ID:
- 799772
- Report Number(s):
- DOE/NV-816; TRN: US200222%%486
- Resource Relation:
- Other Information: Uploaded from BNC CD received 9/2002; PBD: 1 Apr 2002
- Country of Publication:
- United States
- Language:
- English
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