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B-20 Remedial Investigation Report for Former Open Burn/Open Detonation Area
Section 1 - Introduction
This report describes the field methods, results, conclusions, and recommendations of the remedial investigation (RI) conducted in November and December 1994 at the B-20 former open burn/open detonation (OB/OD) area at Camp Stanley Storage Activity (CSSA) in Boerne, Texas. This work was performed by Parsons Engineering Science (Parsons ES), previously Engineering-Science, Inc. (ES), under contract to Armstrong Laboratory/OEB at Brooks Air Force Base (AFB), Texas.
Closure of the B-20 former OB/OD area is being conducted in compliance with a Compliance Order sent to CSSA on June 30, 1993. The U.S. Environmental Protection Agency (EPA), Region VI, Resource Conservation and Recovery Act (RCRA) Enforcement, Texas Section, issued this compliance order which required that CSSA immediately cease operation of the unit and prepare a closure plan for the unit in accordance with the applicable regulations. The compliance order required that the B-20 closure plan comply with federal and state regulations (40 Code of Federal Regulations (CFR) 265 Subpart G and Title 30 Texas Administrative Code (TAC) Chapter 335 Subchapter S, respectively) for closure of hazardous waste management units.
Parsons ES was contracted by Armstrong Laboratory/OEB to perform investigations at waste management units (WMUs) at CSSA under contract number F33615-89-D-4003,delivery order 126. Work performed under delivery order 126 is defined in the statement of work (SOW) dated September 30, 1993, and the SOW modification dated June 22, 1994. The SOW and the modification are presented in Appendix A.
1.4 - Investigation Objectives and Scope
The goals of this RI are to assess the effect of past waste disposal actions on the environment and to recommend a standard to be applied for site closure. Specific objectives include:
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Determination of the extent and type of unexploded ordnance (UXO) at the site, |
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Assessment of the nature and extent of soil contamination, |
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Assessment of the nature and extent of surface water and sediment contamination, and |
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Recommendation of a closure standard under 30 TAC 335 Subchapter S. |
The scope of this investigation, as presented in the "Partial Facility Closure Plan, B-20 Detonation Area, Camp Stanley Storage Activity"(ES, 1994a),consisted of the following tasks:
Conduct sweep of entire site for UXO.
Examine historical aerial photographs to determine past site uses.
Perform surface geophysical surveys at each site crater.
Drill soil borings for collection of subsurface soil/rock samples.
Collect groundwater grab samples from any borings in which groundwater is encountered.
Collect judgmental surface soil samples from within designated craters, as well as from kick-out zones outside of those craters, and from locations at which there is a high probability for contamination (based on site observations).
Collect systematic surface soil samples at approximate 250-foot intervals across the site.
Collect background samples on CSSA lands of three soil types found at the B-20 site.
Perform data validation using EPA level 3 criteria.
Survey the coordinates of soil borings, surface soil sample locations, sediment sample locations, and surface water sample locations.
Survey site boundaries and site features, including craters, ponds, and cleared access routes.
Perform statistical analysis of background metals levels to determine 95% upper tolerance limits (UTLs).
Evaluate nature and extent of soil, surface water, and sediment contamination.
Section 1 is this introduction describing the purpose of this report, the laws that govern this investigation, the contract authorization, and the objectives and scope of the work.
Section 2 describes the background of CSSA and the B-20 site, including the environmental setting and land use. It also summarizes results of a previous investigation performed at the site in January and February 1994.
Section 3 describes the application of RCRA closure guidance and the Texas Natural Resource Conservation Commission (TNRCC) risk reduction standards towards closure of the B-20 site.
Section 4 describes the investigation methodologies and activities. Section 5 presents investigation results, and Section 6 presents the conclusions.
Section 7 describes closure options and the activities that must be conducted at the site to prepare it for closure, using four closure scenarios (standard 1, standard 2, standard 3, and a combination). Section 8 lists references.