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fir I Mr Martin Harris March 22, 2000 . Page 2 of 5 February 5, 1999 Soil samples collected beneath the tank contained ethylbenzene and total xylenes at levels exceeding the respective laboratory detection limits No groundwater was encountered dunng UST removal Analytical results of soil samples collected beneath the former UST are summarized in Table 1 Soil sample locations are shown on Figure 2 2.2 Investigations Undertaken In accordance with the approved workplan dated December 3, 1999, a total of three soil bonngs were advanced at the site to investigate the extent of residual soil contamination and the potential threat to shallow groundwater beneath the site Bonng SBI was located five feet north of the former UST location, boring S132 was located approximately 15 feet north of SBI, and boring SB3 was located 15 feet west-southwest of the former tank pit Soil bonng locations are depicted on Figure 2 3.0 INVESTIGATIVE PROCEDURES On December 17, 1999, Sean Garvey of Ground Zero arrived at the site to supervise dnlling and sampling activities Ms Lon Duncan of San Joaquin County Public PHS/EHD conducted a site inspection and observed field activities Fisch advanced the bonngs under the supervision of field geologist Sean Garvey, and project . manager John Lane, a California Registered Geologist, to explore the lateral extent of residual contamination and the potential threat to shallow groundwater beneath the site The bonngs were advanced to a depth of approximately 26 feet below ground surface (bgs) Fisch utilized a truck mounted Geoprobe 5400 direct push rig to advance the bonngs and collect soil samples Soil samples were collected at 5-foot intervals using a 1 -3/4 inch diameter by 24-inch long core sampler The sampler was lined with clear acetate sleeves, affording soil identification and subjective evaluation for contamination A flame ionization detector (FID) was used to monitor the presence of volatile organic compounds in the soil Three soil samples from each boring were sealed, labeled, and immediately placed in an iced cooler for transport to a state-certified analytical laboratory Soil samples were selected based on observations and field screening results "Grab" groundwater samples were collected from bonngs SB 1 and SB2 by driving a core sampler to the desired depth before exposing the screen to the formation Groundwater was extracted through PTFE tubing inserted into the rods to the bottom of the sampler, and transferred directly into appropnate labeled glass containers The containers were then sealed, and placed into a cooled ice chest for transport to Argon Laboratones The completed bonngs were backfilled to the ground surface with neat cement grout through the drilling rods No soil cuttings were generated All down-hole dnlling and sampling equipment was decontaminated by washing with a laboratory grade detergent and rinsing with water Rinseate collected from decontamination procedures was disposed of by Fisch • RESULTS OF INVESTIGATION datalgroundze\tufiboylreportsrsubsursum doc