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SWMU B-26 Delisting Report
Section 2 - Delisting Activities
With the goal of site closure under RRS1, the SWMU B‑26 RFI Report (Parsons, 2002) recommended excavation of a test pit to investigate a geophysical anomaly located in the northwest portion of the site. If waste material was encountered, it was recommended the waste be characterized and disposed, and confirmation sampling should be performed to verify all waste and waste residue was removed. After field activities were completed, the soil piles at the site were to be re-graded back into the trench and the entire site leveled out.
A test pit was excavated in December 2003 to determine if buried waste was present in the northwest portion of the site, at the location of a geophysical anomaly. During this excavation, between 8 and 10 cubic yards of soil were excavated from the site. The recovered waste material that accounted for the geophysical anomaly, a single small piece of tin, was removed from the test pit area. After excavation, the soil was replaced into the test pit. Since no waste was discovered during the excavation, the site does not qualify as a SWMU and confirmation sampling was not warranted. All excavation activities were conducted by Eagle Construction and Environmental Services, Inc. of San Antonio, Texas, with oversight by a Parsons Field Team Leader.
2.2 - Soil Mound Sampling
On December 18, 2003, two samples were collected from the soil piles at either end of the SWMU B‑26 trench (one sample from each pile). These samples were collected to confirm that the mounded material was not associated with waste management activities.
The samples were analyzed by APPL, Inc. (Fresno, California) for arsenic, barium, chromium, copper, nickel, zinc by method SW6010B, lead by method SW7421B, cadmium by method SW7131A, and mercury by method SW7471A. Since VOCs or SVOCs, with the exception of a common laboratory contaminant bis(2-ethylhexyl)phthalate, were not detected during the RFI, the soil mound samples were not analyzed for these compounds. All results for each sample were below established background levels and are presented in Table B26-3. After it was confirmed that the soil pile samples met RRS1 criteria, the piles were leveled into the trench at B‑26 (Figure B26-10).