[Home] [Master Table of Contents]

[Table of Contents]

AOC 39 RFI/Closure Report

Section 3 - Conclusions and Recommendations

3.1 - Conclusions

There are no records indicating that AOC 39 was ever used for waste disposal nor are there any surface indications of waste or trenches. A geophysical survey was conducted in 1995 on AOC 39, in which the site was referred to as “Well 16 West.” Two EM geophysical anomalies were detected in that geophysical survey. 

The locations of these anomalies correspond to locations of abandoned livestock supply wells CS-B and CS-C. The 1995 soil gas survey results obtained during investigation of the area west of well CS-16 (now designated AOC 39), indicated low levels of PCE in seven of nine samples. Additional surface soil samples were collected from depths of up to two feet in January 2000 to evaluate the occurrence of chlorinated hydrocarbons in the soil gas plume in the vicinity of well CS-16. No VOCs were detected in the five surface soil samples collected at the site.

3.2 - Evaluation of Data Quality Objectives Attainment

Overall data quality objectives (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 AOC 39, along with an evaluation of whether each DQO has been attained, is provided in Appendix C. As described in Section 1, the main objectives of the AOC 39 investigation are to determine if the site meets TNRCC requirements for RRS1 closure and to meet requirements of the 3008(h) Administrative Consent Order.

All data generated during the AOC 39 investigation were reviewed to confirm conformance with the AFCEE QAPP. Approval of the data packages by AFCEE was obtained on May 22, 2000. The data verification report is included in Appendix B. All data are considered usable for site characterization and closure purposes. 

3.3 - Recommendations

Closure under RRS1 is recommended for AOC 39. Although low levels of chlorinated hydrocarbons were detected in soil gas samples collected at the site in 1995, surface soil samples indicate that these analytes are not detectable in surface soil. The soil gas concentrations detected at AOC 39 are part of a larger soil gas plume in the vicinity of Well CS-16, originating at the most likely source areas SWMU B-3 and SWMU O-1. Investigation does not indicate that a VOC release has occurred at AOC 39. The 1995 EM geophysical survey indicated the presence of two unexplained anomalies. These anomalies correspond with the locations of abandoned livestock water supply wells, which were found during research associated with the Offsite Well Survey Report (Parsons, 2001c).

3.4 - Certification

Partial Facility Closure Certification

Area of Concern 39

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.