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Diesel Impacted Soil Removal Report May 2010 California Army National Guard Armory Lodi, CA 3.0 DESCRIPTION OF REMOVAL ACTIVITIES The following discussion summarizes activities related to subsurface clearance,pre-characterization sampling, diesel fuel impacted soil excavation and disposal, confirmation sampling, and site restoration. All activities were performed in substantial accordance with procedures outlined in the December 2009 Workplan. 3.1 SITE CLEARANCE On January 28,2010, OTIE coordinated clearance from underground utilities in the immediate vicinity of the diesel spill using Precision Locating(Precision), a California-licensed underground utilities-locating contractor. The purpose of this procedure was to ensure clearance from underground utility lines (e.g., water, sewer,telecommunications, cable television, electric, gas, etc.)that might be impacted by either pre-characterization sampling activities or by excavation activities to be performed subsequent to pre- characterizing soils in the area. In accordance with California law,the proposed excavation area was properly marked prior to notifying Underground Service Alert(USA) about proposed subsurface excavation activities. Following USA notification,Precision performed a geophysical survey of the pre-characterization and proposed excavation area footprint.No subsurface utilities were identified in the immediate area of the proposed excavation area footprint by either USA or Precision. Photographs documenting site clearance activities are presented with the photographic log in Appendix B. 3.2 PRE-CHARACTERIZATION SAMPLING On January 28,2010, following underground utilities clearance as described above, OTIE collected nine pre-characterization soil samples at depths ranging from 12 to 40 inches below ground surface (bgs). The approximate locations of these samples (LODI-SO-01 through LODI-SO-09) are shown in Figure 3 (Appendix A). The locations for these samples were based on visual inspection and field judgment of impacted soils. The objective of the sampling effort was to determine an accurate estimate of vertical and lateral extent of impacts so that the volume of soils requiring excavation could be quantified. OTIE collected soil samples from within the visibly stained area and up to 2 feet beyond the visible edges of that area using a hand auger which was decontaminated prior to collection of each sample. Soil samples were placed into sterile glass containers,preserved in accordance with analytical methodology protocols, and submitted under chain-of-custody documentation to Curtis &Tompkins, Ltd. (C&T), an analytical laboratory having California Environmental Laboratory Accreditation Program(ELAP) and USACE ELAP certifications. C&T analyzed the samples for extractable petroleum hydrocarbons, or Total Petroleum Hydrocarbons as Diesel Fuel(TPH-D)by gas chromatography(GC)using United States Environmental Protection Agency(EPA)Method 8015B. Consistent with the strategy in the Workplan, a threshold of 100 milligrams per kilogram(mg/kg)was used as a cleanup goal for TPH-D. Although not strictly applicable to this site,this threshold has historically been used in relation to the California Leaking Underground Fuel Tank(LUFT)protocol for managing and remediating LUFT sites and represented a reasonable point of reference concentration for comparison of results. In accordance with this strategy, soil shown via pre-characterization sampling to exceed the 100 mg/kg threshold would be excavated and disposed. Photographs and field notes documenting pre-characterization sampling activities are presented in Appendices B and C,respectively. Pre-characterization sampling results are presented in tabular form in Section 4.1.