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SWMU B-33 Closure Report
Section 3 - Closure Certification
3.1 - Conclusions and Recommendations
SWMU B‑33 includes pipe bedding material near Building 45. The bedding consisted of sand and intermixed projectiles from weapons testing operations. During initial investigations, sand and spent projectiles were uncovered in areas along the piping, especially toward the south end of the pipe location. Sand and spent ammunition jackets were also present at the surface where the water supply pipe entered Building 45. In 1997, contaminated backfill materials were excavated and disposed of in accordance with applicable regulations. Then the area was backfilled and graded. At that time, a small amount of contaminated bedding material still remained near the foundation of Building 45. Excavation of the remaining contaminated bedding material occurred in March 2004, and a total of 18 CY of waste and sand material was removed from the site.
Analytical results for SWMU B‑33 from the 1997 RFI sampling indicated that soils met RRS1 criteria for metals and explosives. However, the analytical results for SWMU B‑33 bedrock (Glen Rose Limestone) indicated that the metals barium, chromium, nickel, zinc, cadmium, and lead exceeded RRS1 standards, in at least one sample. Although some of the bedrock samples collected for the RFI Report exceeded RRS1 criteria, no additional sampling in the bedrock was performed at SWMU B-33 because field observations made during the boring program indicated that limestone was interbedded with marl, and this material is more comparable to CSSA soils rather than the Glen Rose Limestone. Therefore, the background concentrations for soils may be a more appropriate standard of comparison. The reported concentrations of barium, chromium, nickel, zinc, cadmium, and lead are all below established RRS1 soils values, and concentrations for all but one of these samples were below the Texas-specific median background values. The nickel concentration reported at 10.1 mg/kg in sample RW‑B33‑SB03 (12 to 12.5 feet) only exceeds the Texas-specific median background concentration by 0.1 mg/kg and is still well below the soil background level of 35.5 mg/kg.
Metals concentrations were reported at levels below background concentrations for confirmation soil samples collected as part of the closure activities. Therefore, based on the confirmation sampling results and the discussion presented above, it is recommended that SWMU B‑33 be closed under RRS1.
3.2 - Evaluation of Data Quality Objectives Attainment
Overall DQOs for the investigations at CSSA are provided in Volume 1-1 behind the RFI Addendum tab (Section 11 of the Work Plan Overview). A detailed list of DQOs for SWMU B‑33, along with an evaluation of whether each DQO has been attained, is provided in Appendix B. As described in Section 1, the main objectives of the SWMU B‑33 investigation was to determine if the site meets TCEQ requirements for RRS1 closure and to meet requirements of the 3008(h) Administrative Consent Order.
All data generated during the SWMU B-33 investigation were reviewed to confirm conformance with the AFCEE Quality Assurance Program Plan (QAPP); the data verification report is included in Appendix C. All data flagged with “F”, and “M” are considered useable for site characterization purposes. Although several results are flagged with an “M”, these results are considered useable because the matrix interference is minimal and does not significantly affect the sample results.
Partial Facility Closure Certification
Solid Waste Management Unit B-33
Department of the Army
Camp Stanley Storage Activity
Boerne, Texas
I certify that the above-described closure was performed under my direction, in accordance with the work plan and 30 TAC §335 Subpart S, and as described in this report, and that, to the best of my knowledge and belief, said closure has been successfully accomplished.
Jason D. Shirley
LTC Jason D. Shirley
Installation Manager, Camp Stanley Storage Activity
Date
Kirk W. Lawson
Kirk W. Lawson, P.E.
State of Texas #79204
Parsons
Date