[SWMU Bldg. 43]

SWMU Building 43

RL53 Work Plan Addendum

Soils: Tarrant Association, gently undulating

Known: Building 43 is an inactive makeshift ammunition demolition facility used to burn miscellaneous solid waste and ammunition. The area adjacent to Building 43 is covered with molten metal and spent ammunition.

Previous Investigations: Soil gas survey performed in area around Building 43 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 building is only about 20 by 25 ft., the interval was not adequate to characterize the Building 43 site. In addition, a visual inspection was conducted by UXO trained technicians in September 1997 for UXO clearance. Using magnetometers, they located several spent small caliber cartridges and projectiles and a small number of spent fuses. No live ordnance was located on the surface, and none is thought to be buried in this area. Figure Bldg 43-1 is a site map of Bldg. 43.

Data Needs: Analytical data from surface and subsurface soils.

Rationale for Analytical Program: Based on prior usage at the site as a makeshift ammunition demolition facility to burn ammunition, chemicals of potential concern include 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. SVOCs and VOCs are not included at this site since evidence at the site includes molten metal and spent ammunition.

Closure Activities: The following field activities will be performed to gather data for closure of SWMU Building 43.

SWMU Building 43 Field Effort 2

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

  2. Three Surface soil samples will be collected for site characterization and analyzed for SVOCs.

  3. Six soil borings will be drilled to characterize the subsurface soils surrounding the building. Three soil samples will be collected from each boring; one at the surface, one near the middle of the boring and one at the total depth. The total depth of each boring will be approximately 20 feet or until bedrock is encountered. Each sample will be analyzed for VOCs, explosives, and metals.

  4. Water is not expected to be encountered at the site. However, if water is discovered in any of the soil borings, all borings will be sampled and potentially completed as groundwater monitoring wells as detailed in Section 2.4.1 of the Work Plan Overview. Groundwater will be sampled, where contamination is present, and each sample will be analyzed for VOCs, explosives, and metals identified in the soil samples.

  5. If necessary, soil beneath the building will also be excavated after coordination with the State Historical Preservation Office. Soil surrounding the building may be excavated.

  6. The excavated soil will be sampled for characterization for disposal purposes. Samples will be collected at a rate of one per 50 cu. yds.

  7. To determine if the excavated bottom meets RRS1 criteria, three samples will be collected from the bottom of the area surrounding Building 43 along with one sample collected from each sidewall. All samples will be analyzed for contaminant(s) of concern identified from surface and subsurface investigation efforts.

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

  9. 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 state closure requirements. If the site does not meet RRS1 closure requirements, a technical report describing the results of the investigation and recommended additional investigation and/or remediation will be prepared.