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15 June 2016 <br />AGE Project No. 14-3154 <br />Page 3 of 5 <br /> <br />Advanced GeoEnvironmental, Inc. <br /> <br /> <br /> <br /> <br />A total of eight soil samples were collected within noted soil depressions or low areas. Six <br />samples were collected at six to eight inches bsg of the depression (ABSP1A-ABSP2C). <br />Additionally, two deeper soil samples were later collected at the location of ABSP2B, at <br />depths of 1.5 feet and 3 feet bsg of the base of the depression. <br /> <br />A total of four shallow soil samples collected from these areas indicated minor detections <br />of PCBs (Aroclor 1254 only). The depth of each of the samples is approximately 8 to 10 <br />feet below the natural land grade and therefore are not shallow soils. Additionally, the <br />Department of Toxic Substance Control HHRA Note 3 (May 2015) listed screening levels <br />for general PCBs at 0.78 mg/kg which is greater than all the soil sample detections. <br /> <br />Soil stockpile pile samples from the glass management area (S series) with detections of <br />metals, were below the California Human Health Screening Level (CHHSL) <br />concentrations and consistently detected low total metals concentrations. Soluble metals <br />concentrations were generally low or typical for background concentrations on <br />commercial land. <br /> <br /> <br />WASTE REMEDIATON <br /> <br />During the initial investigation of the former PNA site, the majority of the trenches (T1 to <br />T23) demonstrated minor amounts of residual glass present within native soils. Trenches <br />established within the stabilized cover area T1 to T23 (July 2015) produced minor glass <br />waste and mostly clean native soil. In August 2015 waste was transported to Forward <br />Landfill in Manteca, CA for disposal. Approximately 297 tons of waste glass, minor <br />garbage and cover soils were disposed. <br /> <br />At the direction of State of California – CalRecycle, a limited ground penetrating radar <br />survey (GPR August 2015) initially indicated limited amounts of buried glass across the <br />area of T1 to T23. A secondary GPR and magnetometer survey conducted at the <br />southwest boundary of the property and off-site, indicated the presence of buried glass <br />and ancillary metals across two cells, generally limited near the southwestern portion of <br />the investigation. <br /> <br />A set of trenches (later in August and throughout early September 2015) at the southwest <br />boundary of the property (south cell T46, T48, T50, T58 and T59 and north cell T64, T65, <br />T70) evaluated and also demonstrated a differing thickness (topology) of the potentially <br />buried waste. The waste strata over native soil ranged from 18 inches at trench T46 to <br />10 feet deep at trench T58 (south waste cell) and to 13 feet deep at trench T65 (north <br />waste cell) areas. <br /> <br />Two waste cells of approximately 2,000 square feet of area each (30 to 35 feet north- <br />south to soil and 65-70 feet east-west) had demonstrated some waste glass and debris, <br />with a variable thickness. The southern cell was approximately eight feet deep and the <br />northern cell was approximately thirteen feet thick.