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Soil Excavation Summary Report, August 28,2014 <br /> ' Combined Support Maintenance Shop, 14 <br /> California Army National Guard <br /> Due to the vertical extent of impacted soil on the northern portion of the excavation, more soil <br /> ' was required to be excavated than anticipated. Based on conversations with Captain Kinney <br /> in the field, he recalled the spill may have originated on the northern portion of the excavation <br /> and migrated in a southern direction due to the slope of the ground surface. This information <br /> ' is consistent with the soil staining pattern observed during excavation activities. <br /> Per the request of Ms. McCartney, SJCEHD Inspector, two soil confirmation samples were <br /> collected using direct grab methods and transferred into pre-cleaned amber glass jars <br /> ' provided by the analytical laboratory. The first and second soil confirmation samples were <br /> collected from the southeast and southwest portion of the excavation floor, respectfully. <br /> ' Soil confirmation samples were submitted to BC Laboratories Inc., a California State Certified <br /> Laboratory, under chain-of-custody protocol, for analysis of: <br /> ' Total Petroleum Hydrocarbons as Jet Fuel (TPH-Jet) by Environmental Protection Agency <br /> (EPA) Method 8015; and <br /> • Polycyclic Aromatic Hydrocarbons (PAHs) by EPA Method 8270 Selective Ion Monitoring <br /> ' (SIM). <br /> TPH-Jet is a middle distillate fuel (e.g. jet fuel, diesel, kerosene) that primarily contains PAHs. <br /> 1 ECM's original proposal stated that semi-volatile organic compound (SVOC) analysis would <br /> be performed. However, SVOCs are a group of compounds that include PAHs, pesticides, <br /> herbicides, polychlorinated biphenyls, phthalates (generally founds in plastics), among other <br /> ' compounds. Since TPH-Jet primarily contains PAHs, SVOC analysis was not warranted. As a <br /> result, ECM selected PAH analysis by EPA Method 8270 Selective Ion Monitoring (SIM). SIM <br /> analysis was selected to allow for lower detection limits required to meet the regulatory <br /> ' screening levels. <br /> Detectable concentrations of TPH-Jet and PAHs were compared to the following regulatory <br /> screening levels (Industrial land use was assumed for all screening levels): <br /> ' <br /> • San Francisco Regional Water Quality Control Boards, Environmental Screening Levels <br /> (FSCs); and <br /> ' • US EPA Region 9, Regional Screening Lev <br /> Currently, <br /> S h <br /> ' Currently, ESLs and RSLs for TPH-Jet do not exist. Since TPH-Jet is a middle distillate, <br /> compounds within the middle distillate category were selected as surrogate screening levels. <br /> As a result, TPH as diesel (TPHd) and the TPH aliphatic medium were selected for the ESL and <br /> RSL, respectfully. Both these compounds fall within the middle distillates range and are <br /> ' comparable to TPH-Jet. <br /> 2.5 Site Backfill, Compaction, and Restoration <br /> ' On June 30, 2014, approximately 14 cubic yards of clean backfill material and 2 cubic yards of <br /> gravel were brought onsite by Allen's Loam Sand and Soil, located in Stockton California. The <br /> ' excavation was backfilled in approximately 6-inch lifts and the soil was compacted using the <br /> backhoe bucket or the wheels of the excavator (Attachment A- Pictures 3 and 4). Gravel was <br /> placed at grade to complete the backfill and restoration (Attachment A- Pictures 5 and 6). <br /> 1 <br />