[Home]

[Closure Report] [Next Section]

SWMU O-1 Interim/Stabilization Measures and Partial Facility Closure Report

Section 3 - Conclusions

3.1 - Conclusions

The Texas RRR, codified in 30 TAC §335 Subpart S, establish comprehensive, risk-based standards for closure/remediation of soils, groundwater, surface water, and air contamination problems. Three alternate levels of environmental remediation referred to as RRS1, RRS2, and RRS3 are allowed. For each RRS, the rules outline relevant requirements for site characterization, media cleanup levels, verification sampling and testing, project documentation, and deed recordation.

After review of site data (discussed in Section 1) and the TNRCC RRR for closure of waste management units, CSSA decided the most appropriate closure of SWMU O-1 was under the strictest standard—RRS1 (30 TAC §335.554). This standard requires that the site be closed following removal or decontamination of waste, waste residues, and contaminated operation system components and demonstration of attainment of cleanup levels. If closure requirements under RRS1 are attained and approved by the TNRCC Executive Director, then the owner is released from deed recordation requirement.

For COCs, cleanup levels for environmental media must correspond to either background levels or the PQLs. If the PQLs are greater than background level, the PQLs rather than the background level shall be used as the cleanup level. For the closure criteria of SWMU O-1, CSSA adopted the AFCEE QAPP RLs as the PQLs for meeting the specified requirements of the RRS1 closure standard. Parsons ES requested, on behalf of CSSA, use of the CSSA/AFCEE RLs by letter dated July 12, 1999 and TNRCC approved use of the RLs for investigations and closures by letter dated October 5, 1999. These letters are in the CSSA Environmental Encyclopedia (Volume 1-1, Correspondence with Regulatory Agencies). The order of constituent analysis precision is first the MDLs, then RLs, and then PQLs. Thus, RLs have lower concentrations than PQLs, and are more conservative, i.e., environmentally protective, than PQLs.

Since the COCs for SWMU O-1 are VOCs and metals cadmium and chromium, the cleanup levels should be the RLs for the VOCs and background levels as established for the Tarrant soils located at CSSA. Background levels were established in 1996, see the CSSA Environmental Encyclopedia (Volume 2, Background Metals Levels). However, because fraudulent and invalid data from the laboratory was utilized in establishing these background data, new background data was generated. CSSA background metals levels are currently pending regulatory approval..

CSSA is seeking a partial facility closure of the surface soil zone located within the boundaries of SWMU O-1. The underlying limestone and the groundwater bearing zones are not included as part of this partial facility closure. The limestone/groundwater zone will be addressed when a final remedy solution is available for these operable units.

Analytical results and the IM removal actions have resulted in no volatile hydrocarbons being present above RL concentrations at SWMU O-1 nor metals above background levels; therefore, RRS1 has been attained. CSSA therefore requests TNRCC approval of a partial facility closure of the surface soils at SWMU O-1 under RRS1.

Specified IM actions were accomplished through removal of all soil‑based contaminants at the site and construction of a low-permeability soil cover over the area of the former soil contamination. The cover will serve to prevent infiltration of precipitation into and through the bedrock and groundwater which remain contaminated, thereby serving to mitigate, control, abate, and minimize spread of contamination in the groundwater below.

3.2 - Certification

Partial Facility Closure Certification

Solid Waste Management Unit SWMU O-1

Department of the Army

Camp Stanley Storage Activity

Boerne, Texas

I certify that closure of surface soils at SWMU O‑1 was performed under my direction, in accordance with the Work Plan and as described in this report, and that to the best of my knowledge and belief, said closure has been successfully accomplished in accordance with 30 TAC §335.554.

[Next Section]