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Soils: Krum Complex.
Known: The site consists of suspected 155-mm shells containing mustard gas that were buried and detonated in 1942. Located in the area between Well 16 and SWMU B-3, southeast of Well 16.
Previous Investigations (Updated): On 15 May 1958, field efforts were conducted to assist in the detection and disposal of any remaining shells and chemical warfare agents (CWA). The area was decontaminated for possible residual mustard using calcium hypochlorite (bleach). On 23 May, a certificate was signed by the Technical Escort Unit head stating that to the best of his knowledge all suspected 155-mm mustard filled rounds and resultant scrap metal buried in July 1942 were recovered, destroyed and decontaminated.
Under Order 71, Parsons ES reviewed the 1957 and 1962 aerial photographs in 1992 and 1993.
Under Order 67, a geophysical survey was conducted in May 1995 at all "open" areas within a 2,000-foot radius of Well 16. No anomalies were found in this area, labeled southeast Well 16 at the time, and is now included as AOC 36.
In June and July 1995, twenty-nine soil gas survey samples were collected and analyzed for chlorinated and aromatic volatile organics. PCE (28 ug/L), TCE (0.98 ug/L) and DCE (8.2 ug/L) were detected in this area. In November 1995, an additional 10 soil gas survey samples were collected. Carbon tetrachloride, PCE, TCE and DCE were detected.
Under RL33, the site was identified as a mustard gas burial site on the 1942 map of CSSA. On 18 February 1997, the site was surveyed and an area of approximately one acre was marked for further investigation. Interviews with two former CSSA personnel were conducted, and they identified the general area within which the mustard gas shells had been buried.
On 26 February 1997, a Forester Ferex (Mk-26) magnetometer sweep of the former surveyed areas and the area identified by the former CSSA personnel. UXO items were segregated in the area for future disposal by UXB personnel, and metal items that were free from explosives were placed in a roll-off container for recycling.
In June 1997, areas with noted anomalies (observed during the magnetometer sweep) were excavated for buried UXO and mustard gas shells. Excavated soils were sifted during these operations. No mustard gas shells or evidence of mustard gas shells were identified throughout the site. Schonstadt GA-52B Locators were used during excavation activities to verify removal of anomalies.
On 18 March 1999, the final investigation report for field activities at this site was submitted to the TNRCC for review. On 19 July 1999, TNRCC concurrence with the closure report was granted. No further actions with regard to mustard gas are required for this site.
Data Needs: Analytical data (VOCs – TCE, PCE, and DCE) for surface soils.
Rationale for Analytical Program: Based on the site’s vicinity to well 16 and previous investigations at the site, chemicals of potential concern include VOCs, (TCE, PCE, and DCE). Metals, explosives, and SVOCs are not included due to the results of geophysical surveys completed in the area.
Closure Activities: The following activities constitute an initial investigation of AOC 36. This work will be completed as part of the requirements under the RCRA 3008(h) Order under AETC delivery order 5068.
Collect ten surface grab samples to a maximum depth of 2 feet to characterize surface soils surrounding the area. The surface samples will be collected in a grid-like fashion, and will biased toward the soil gas survey points with the highest PCE readings. Figure AOC36-1 depicts the proposed locations for the surface samples. This work is being performed in conjunction with sampling efforts at AOCs 38, 39, and 40. Each sample will be analyzed for VOCs – TCE, PCE, and DCE. QA/QC samples will be collected as described in Section 2.4 of the FSP.
Handle IDW as specified in the FSP.
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.