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AETC Work Plan Addendum

Soils: Krum complex.

Known (Updated February 2001): The site consists of an area with rust-colored material consisting of suspected nickel penetrate at ground surface. It is located south of SWMUs B-29 and B-30 along the path of a gravel road, and is approximately 0.5 acres in size. As many as seventeen distinct areas of nickel penetrate were identified during the initial site visit in which the site was mapped (Figure AOC50-1). Samples of the waste material were collected and found to be non-hazardous by TCLP criteria.

Spent munitions and potential UXO were discovered at the site in January 2000. Surface vegetation was cleared from the site in February 2000 and the Army removed munitions-type surface debris. An area of potential subsurface disturbance was identified by CSSA personnel at the southern edge of AOC 50.

Previous Investigations: Site was located on 5 March 1996 during previous field efforts.

Data Needs (Updated February 2001): Map and analytical data (VOCs, explosives, and metals) for surface soils.

Rationale for Analytical Program: Based on the rust colored material consisting of suspected nickel penetrate at the ground surface, the chemicals of potential concern include metals. Metals (arsenic, barium, cadmium, chromium, copper, lead, mercury, nickel and zinc) are included due to the metallic nature of the waste. The presence of VOCs and explosives will also be analyzed with the advent of additional waste types discovered in January 2000.

Original Scope of Work (May 2000): The following activities constitute an initial investigation of AOC 50. This work will be completed as part of the requirements under the RCRA 3008(h) Order under AETC delivery order 5068.

  1. Field map AOC 50 as described in Section 2.4.1 of the Work Plan Overview.

  2. Excavate up to 100 cubic yards of suspected nickel penetrate and underlying soils from the surface. Visible suspected nickel penetrate fragments will be collected and segregated prior to the over-excavation of surface soils. Collect four confirmation soil samples to an approximate depth of 2 feet. The samples will be biased toward any observed soil contamination remaining after excavation activities are complete. Each sample will be analyzed for metals. QA/QC samples will be collected as described in Section 2.4 of the FSP.

  3. IDW will be handled as specified in the DO 5068 FSP Addendum.

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

Revised Scope of Work (August 2000): This revised scope of work provides allowances for a geophysical survey, additional excavation volume, sampling, waste characterization, and as well as providing UXO avoidance by a qualified subcontractor. The SOW was revised on August 2, 2000, and is reflected in this version of the work plan.

  1. Up to a one-acre geophysical survey will be completed along the southern margin of the site in the vicinity of a potential subsurface disturbance (Figure AOC50-2). The geophysical survey will be conducted as described in Section 2.4.1 of the Work Plan Overview. A ground penetrating radar (GPR) device and an EM-31 instrument will be used to complete the geophysical survey. The locations of four of the corners of the survey points will be recorded using a GPS unit.

  2. A geophysical reconnaissance survey will be conducted over the extent of the IM excavation area using an EM-31 only (Figure AOC50-2). The purpose of this sweep will to tentatively identify areas where nickel penetrate are located, and if any other disturbances are present within the planned excavation limits. Analysis of the EM data will be completed prior to the initiation of IM excavation activities.

  3. A UXO subcontractor will be present to assist in the direction of the excavation activities. The subcontractor will sweep the area of excavation, flag potential targets or hazards, and provide support to complete the task. Finds of the EM-31 reconnaissance survey will aid in identifying target locations.

  4. Excavate up to 175 cubic yards of suspected nickel penetrate and underlying soils from the surface. Figure AOC50-1 outlines the general area in which nickel penetrate has been observed. Visible suspected nickel penetrate fragments may be collected and segregated prior to the over-excavation of surface soils if the wastes can be accepted by a recycling facility. On average, up to three inches of soil may be excavated from the entire 0.5-acre site. The over-excavation depth may vary, as long as no more than 175 cubic yards of total soils and waste are removed.

  5. Collect ten confirmation soil samples to an approximate depth of 2 feet. The samples will be biased toward any observed soil contamination remaining after excavation activities are complete. Each sample will be analyzed for metals, VOCs, and explosives. In addition, nine TCLP samples of the nickel penetrate will be collected and analyzed for metals, VOCs and total explosives for disposal purposes.

  6. If any anomalies are found within the target area during the geophysical survey, slit trenches in the surface disturbance areas can be completed during the IM excavation. These trenches will aid in identifying if waste is present, and if so, what type of waste. If any TCLP analyses are available from the nickel penetrate excavation, these may be substituted for environmental characterization.

  7. QA/QC samples will be collected as described in Section 2.4 of the FSP.

  8. IDW will be handled as specified in the DO 5068 FSP Addendum.

  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 TNRCC closure requirements. If the site does not meet RRS1 requirements, a technical report describing the results of the investigation and recommended additional investigation and/or remediation will be prepared. (The overall objective is to collect sufficient data to determine if the site can be closed; and if possible, to close it. Initially, RRS1 for the closure will be used. If closure to RRS1 is not viable, then the data will be compared to TRRPS for an acceptable closure. Clean closures using RRS1 standards will be obtained whenever technically and economically possible.)

Figure AOC50-1

Figure AOC50-2