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AOC 54 Final Closure Report
Section 2 - Closure Activities
The initial intent of current work at AOC-54 was to conduct a Resource Conservation and Recovery Act (RCRA) Facility Investigation (RFI). No samples had previously been collected at the site. Surface soil samples for metals and pH analyses were planned for this current phase of work.
A large metal plate was identified at the site prior to collecting the surface soil samples, and it was decided to remove the plate prior to sampling. On November 19, 2003, the large metal plate was removed and recycled. Subsequently, on December 29, 2003, five surface soil samples were collected and analyzed for pH and barium, chromium, copper, nickel, and zinc (SW6010B), arsenic (SW7060A), cadmium (SW7131A), lead (SW7421), and mercury (SW7471A).
Nickel was detected at a concentration of 53.9 mg/kg in sample AOC54-SW01, which exceeds the background concentration of 35.5 mg/kg. Lead exceeded background (84.5 mg/kg) in samples AOC54-BOT01 (87.96 mg/kg) and AOC54‑SW01 (191.49 mg/kg); therefore, those areas were over excavated in February 2004. Sample locations are shown in Figure AOC54-6.
Approximately 31 cubic yards of soil were excavated on February 27, 2004 from the areas associated with the original AOC54-BOT01 and AOC54-SW01 sampling locations. Photographs of the excavation event are shown in Figure AOC54-5. No obvious waste residue nor odors were observed during excavation activities. Following excavation, these areas were resampled as AOC54-BOT02 and AOC54-SW05 on March 18, 2004. The March 2004 results for those two sample areas indicate acceptable concentrations of lead and nickel (below background levels). Table AOC54-1 presents all confirmation sampling results and appropriate soil comparison criteria.
Excavated soil was stockpiled onsite so the material could be characterized for disposal. Disposal of the waste was conducted on June 1, 2004, under waste profile CG-25591 C‑13. Waste manifests and copies of characterization sampling results are provided in Appendix A. Toxicity characteristic leaching procedure (TCLP) results from the stockpiled waste indicated the material met non-hazardous Class 2 criteria, so the waste was disposed at Waste Management’s Covel Gardens Landfill.
Figure AOC54-5 - Excavation Photographs
Scraping of the site surface during initial excavation, picture taken facing southeast. February 27, 2004
Initial excavation activities, picture taken facing northwest. February 27, 2004
Soil excavation. February 27, 2004