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13 November 2018 <br />AGE Project No. 18-4357 <br />Page 3 of 11 <br />AdvancedGeo <br />Environmental <br />n <br />Following review of the data collected, the SJCEHD directed that soil samples previously <br />collected at 5 feet bsg from S7, S8, S9, and S11 be analyzed to further the assessment. <br />The SJCEHD conveyed this directive in a telephone call with AGE staff on <br />24 October 2018. Soil samples were previously collected from S7, S8, S9, and S11 on <br />14 August 2018, and therefore were past laboratory holding time for TPH analyses. On <br />01 November 2018, AGE mobilized to the site to collect new soil samples from S7, S8, <br />S9, and S11. Soil borings were advanced in the locations of S7, S8, S9, and S11 using a <br />4 -inch diameter hand auger to collect soil samples from 5 feet bsg. The sampling was <br />observed by the SJCEHD. <br />Two areas were excavated (Main Excavation Area and S6 Excavation Area) to remove <br />impacted soil based on: 1) the general location of soil sample S-1 previously collected by <br />the SJCEHD, 2) the location identified by the property owner as having previously <br />identified impacted soil, and 3) impacted soil encountered during the investigation. The <br />remaining locations were potholed (S5 through S11) and hand -augured (S7, S8, S9, S11 <br />and S12) for soil sample collection to define the lateral and vertical extent of impacted <br />soil. The following is a description of the remediated and investigated areas. <br />• The Main Excavation Area consisted of an area of approximately 36 square feet <br />to a total depth of approximately five feet below surface grade (bsg). Following the <br />excavation, confirmation soil samples were collected from each sidewall at a depth <br />of four feet bsg (SW -S, SW -N, SW -W, and SW -E) and from the base of the <br />excavation at five feet bsg (B-5) to confirm impacted soil had been removed. Soil <br />from the excavation was stockpiled next to the excavation and a soil sample was <br />collected for waste characterization (SP -1). <br />• During excavation/potholing of S6, impacted soil was encountered at two feet bsg <br />(S6-2) based on field evidence. Hydrocarbon -like odor and staining was observed, <br />and organic vapor was detected at a concentration of 40 parts per million by <br />volume (ppmv) utilizing an organic vapor meter (OVM) equipped with a <br />photoionization detector (PID; Mini Rae 3000). The excavation area surrounding <br />S6 was expanded to remove impacted soil and was designated as the S6 <br />Excavation Area. An additional area of approximately 36 square feet was <br />excavated to approximately two feet bsg surrounding the S6 sample location. <br />Confirmation soil samples were collected from each sidewall at a depth of two feet <br />bsg (S6SW-S, S6SW-N, S6SW-W, and S6SW-E) and from the base of the <br />excavation at two feet bsg (S613-2) to confirm impacted soil had been removed. <br />Soil from the excavation was stockpiled on-site and two soil samples were <br />collected and then composited by the laboratory for waste characterization (SP- <br />2/SP-3). Additionally, the center of the excavation was extended to five feet bsg to <br />collect sample S6-5 for vertical delineation. <br />• Locations S5 through S11 were potholed on 14 August 2018 and location S12 was <br />hand -augured on 31 August 2018 to approximately five feet bsg to collect soil <br />samples at two feet and five feet bsg to define the lateral and vertical extent of <br />impacted soil; and on 01 November 2018, locations S7, S8, S9, and S11 were <br />