Laserfiche WebLink
Soil Excavation Summary Report, August 28, 2014 <br />Combined Support Maintenance Shop, <br />California Army National Guard 14 <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 />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 />• San Francisco Regional Water Quality Control Boards, Environmental Screening Levels <br />(ESLs); and <br />• US EPA Region 9, Regional Screening Levels. <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 />