Post-Closure Inspection and Monitoring Report for Corrective Action Unit 342: Area 23 Mercury Fire Training Pit, Nevada Test Site, Nevada
This report provides a summary and analysis of visual site inspections and soil gas sampling results for Corrective Action Unit (CAU) 342, Area 23 Mercury Fire Training Pit. CAU 342 is identified in the Federal Facility Agreement and Consent Order of 1996 and consists of Corrective Action Site 23-56-01, Former Mercury Fire Training Pit. This report covers calendar years 2004 and 2005. Visual site inspections were conducted on May 20 and November 14, 2004, and May 17 and November 15, 2005. No significant findings were observed during these inspections. The site was in good condition, and no repair activities were required. Soil gas samples were collected on November 29, 2005, for analysis of volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs), and samples were collected on December 1, 2005, for analysis of base gases. Base gas concentrations in the monitoring well show a high concentration of carbon dioxide and a low concentration of oxygen, which is an indication of biodegradation of total petroleum hydrocarbons (TPH) in the soil. Results for VOCs and SVOCs are unchanged, with VOCs below or near laboratory method detection limits and no SVOCs detected above laboratory method detection limits. Post-closure monitoring was required for six years after closure of the site. Therefore, since 2005 was the sixth year of monitoring, the effectiveness of natural attenuation of the TPH-impacted soil by biodegradation was evaluated. The base gas concentrations indicate that biodegradation of TPH in the soil is occurring; therefore, it is recommended that monitoring be discontinued. Visual site inspections should continue to be performed biannually to ensure that the signs are in place and readable and that the use restriction has been maintained. The results of the site inspections will be documented in a letter report and submitted annually.
- Research Organization:
- National Security Technologies, LLC (NSTec), Mercury, NV (United States)
- Sponsoring Organization:
- USDOE - National Nuclear Security Administration (NNSA)
- DOE Contract Number:
- DE-AC52-06NA25946
- OSTI ID:
- 917995
- Report Number(s):
- DOE/NV-1151; DOE/NV/25946-023; DOE/NV/11718-1259; TRN: US0805200
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
01 COAL, LIGNITE, AND PEAT
BIODEGRADATION
CARBON DIOXIDE
CLOSURES
MERCURY
MONITORING
NATURAL ATTENUATION
NEVADA
NEVADA TEST SITE
ORGANIC COMPOUNDS
TRAINING
CAU 342
Post-Closure Inspection and Monitoring Report
2004 - 2005