RL53 Project, May 2000

Soils: Tarrant Association (gently undulating).

Known: B-10 was thought to be an ammunition disposal area. In August 1997, UXO technicians delineated the area with magnetometers and excavated four test pits across the area to visually inspect the buried material. The test pits revealed buried banding material only.

Previous Investigations: Soil gas survey performed in area around B-10 as part of investigation into potential presence of chlorinated volatile organics between SWMUs B-3 and B-4. As the grid was spaced every 100 ft, and the B-10 trench area is only about 20 by 25 ft, the interval was not adequate to characterize the B-10 site. As mentioned above UXO technicians delineated the landfill area and placed four test pits across the area to visually inspect the buried material. The buried material consisted of metal debris (empty ammunition cans and banding). No UXO items were found. Figure B10-1 is a site map of SWMU B-10.

Data Needs: Additional mapping of the site, collection of surface and subsurface soil samples, excavation of banding material for disposal, placement of three soil borings for surface and subsurface characterization.

Closure Activities: The following activities were completed in an initial investigation of solid waste management unit B-10.

1. Historical records were reviewed as described in Section 2.4.1.

2. A field map has been completed as described in Section 2.4.1, although a more complete map will be produced during the second field effort.

3. Soil gas samples have been collected as described in Section 2.4.1. and analyzed for trichloroethene, tetrachloroethene, cis- and trans-1,2-dichloroethene and the BTEX compounds (as outlined in the FSP). Results of the soil gas survey indicate SWMU B-10 is not a source of VOC contamination.

4. In August 1997, UXO technicians delineated buried material with magnetometers and placed four test pits across the area to visually inspect the buried contents.

The following field activities will be performed to gather additional data for closure of SWMU B-10 in 1999.

1. Notify TNRCC of intent to perform work on the site.

2. The buried contents in the B-10 area will be excavated, characterized, and where appropriate, recycled and/or disposed of properly.

3. The excavated soil and associated material will be sampled for characterization for disposal purposes. Samples will be collected at a rate of one per 200 yd³. Metal debris will be segregated and recycled. Clean soil will be used as backfill for the site.

4. To determine if the excavated area meets RRS1 criteria, four side wasll samples and three bottom samples will be collected from excavated area and analyzed for the contaminants of concern identified through characterization efforts.

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

6. If the results of the above work indicate that the site can be closed under RRS1 without any further remediation, a technical/closure report will be prepared in accordance with TNRCC closure requirements.