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Area of Concern 51

RFI Work Plan Addendum

Soils: Brackett soils and Krum Complex.

Known: The site consists of a large area in the southeast corner of East Pasture, located east of RMU-1. AOC 51 also contains SWMU B-9 and AOC-44, and is approximately 72 acres in size.

Previous Investigations: During cedar clearing activities at the site, UXO items were observed. Under RL33, discovered UXO items were removed in February and April 1997.

Data Needs: Map, geophysical survey and analytical data (VOCs, SVOCs, explosives, and metals) for surface soils.

Rationale for Analytical Program: Based on prior discovery and removal of UXO items, chemicals of potential concern include VOCs, SVOCs, metals and explosives. Metals (arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel and zinc) are included due to the metallic nature of the waste. Ammunition may include explosives residue therefore, an analysis for explosives will be conducted. VOCs analysis is included in the analytical program to detect typical contaminants associated with a disposal area. SVOCs are included at this site since waste burning may have occurred.

Closure Activities: The following activities constitute an initial investigation of the area of concern 51. This work will be completed as part of the requirements under the RCRA 3008(h) Order, but it is not currently included in any delivery order.

  1. Field map AOC 51 as described in Section 2.4.1 of the Work Plan Overview.

  2. Sweep the surface for UXO to identify and remove any remaining UXO items. 

  3. Remove any vegetation necessary to complete field activities listed below. If any potential UXO is observed during field activities, work will cease until UXO specialists are brought on site to identify and remove UXO.

  4. Conduct a geophysical survey, as described in Section 2.4.1 of the Work Plan Overview, of the mapped site to identify any anomalies. A ground penetrating radar (GPR) device and an EM-31 instrument will be used to complete the geophysical survey. The locations of four of the corners of the survey points will be recorded using a GPS unit. Analysis of the EM data will follow field activities.

  5. If the survey information indicates an anomaly is present, complete 15 soil borings to characterize the subsurface soils surrounding the anomaly. Two soil samples will be collected from each boring. The total depth of each boring will be approximately 10 feet. Each sample will be analyzed for VOCs, SVOCs, explosives, and metals. QA/QC samples will be collected as described in Section 2.4 of the FSP.

  6. Water is not expected to be encountered in the borings at the site. However, if water is discovered in any of the soil borings, all borings will be sampled and may be completed as groundwater monitoring wells as described in Section 2.4.1 of the Work Plan Overview. Groundwater will be sampled, where present, and each sample will be analyzed for VOCs, SVOCs, explosives and metals. QA/QC samples will be collected as described in Section 2.4 of the FSP.

  7. IDW will be handled as specified in the FSP.

  8. If the results of the above work indicate that the site can be closed under RRS1 without any further investigation and/or remediation, a technical/closure report will be prepared and submitted in accordance with TNRCC closure requirements. If the site does not meet RRS1 requirements, a technical report describing the results of the investigation and recommended additional investigation and/or remediation will be prepared.