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05 January 2018 AdvraneedGeo <br /> AGE Project No. 14-3154 F n vi rca n rY7 e n to I <br /> Page 3 of 9 <br /> Native soil consisted generally of tan, brown- to dark-brown silts and sands were <br /> encountered between surface grade and approximately 15 feet below surface grade (bsg) <br /> and groundwater is currently observed at depths between approximately 12 to 14 feet <br /> bsg. <br /> Soil samples and grab groundwater samples were collected from the soil borings and <br /> trenches. Soil samples were analyzed for California Title 22 Metals (CAM 17), volatile <br /> organic compounds (VOCs), polychlorinated bi-phenols (PCBs), polynuclear aromatic <br /> hydrocarbon (PNA), polycyclic aromatic hydrocarbons (PAH) or semi-volatile organic <br /> compounds (SVOCs), dioxin and furan, and total petroleum hydrocarbons (TPH). <br /> Analytical results of all soil and groundwater samples (including all lab reports) detected <br /> in trench and boring samples were summarized in the tables provided in the Site <br /> Assessment Summary Report, dated 21 December 2017. <br /> Most grab and monitoring well groundwater samples collected from the site have <br /> demonstrated no direct impact to the water quality or no significant impact to the shallow <br /> groundwater. A grab groundwater sample collected from trench T64, located within the <br /> North Waste Cell, initially demonstrated low concentrations of petroleum hydrocarbons <br /> (TPH-diesel) in the shallow groundwater below the buried waste (Figure 3). No detections <br /> of petroleum hydrocarbons were reported in subsequent grab groundwater samples <br /> collected within the base of the same waste cell (North Waste Cell). <br /> One groundwater sample (AB26-W) collected within the former waste/glass handling area <br /> had a detection of dioxin and furan. Octachlorodibenzo-p-dioxin (OCDD) was detected at <br /> a concentration of 141 picograms per liter(pg/1) or parts per trillion (ppt). The International <br /> toxic equivalency factor for OCDD to 2,3,7,8-Tetrachlorodibenzodioxin (2,3,7,8-TCDD) is <br /> 0.001. Therefore, a toxic equivalency quotient (TEQ) of 0.141 pg/1 was detected. The <br /> detection of OCDD (TEQ) did not exceed and was significantly below the drinking water <br /> quality standard (maximum contaminant level: MCL) of 0.00003 micrograms per liter or <br /> 30 pg/I for 2,3,7,8-TCDD. The two other grab groundwater samples (AB27-W and AB28- <br /> W) collected within the former waste/glass handling area did not have detections. <br /> Additionally, dioxin and furans were not detected above the reporting limits in the <br /> groundwater samples collected from wells W-0 (within the North Waste Cell), W-1 R and <br /> W-2. <br /> Based on soil samples collected in the former glass management area and waste cell <br /> areas, no adverse impact was apparent in the operations of glass waste handling/burial. <br /> None of the metal concentrations (TTLC —Total Threshold Limit Concentration) detected <br /> exceed hazardous waste criteria. Additional analysis of the stockpiled soil/waste and in- <br /> situ soil for soluble metals (STLC — Soluble Threshold Limit Concentration) did not reflect <br /> hazardous waste concentrations. Concentrations of metals detected in samples collected <br /> from spoils removed from trenches T1 through T23 (S labeled series of samples) and the <br /> South Waste Cell spoils pile (S46, S58 and S59)were below the May 2016 Environmental <br /> Protection Agency (EPA) Region 9 Screening Levels for industrial soil (RSLs). Total <br /> metals concentrations were consistently low. Soluble metals concentrations were <br />