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Mr. Jeffrey Wong April 28, 2005 Page 2 of 4 ground surface elevation at the site is approximately 47 feet above sea level. The depth to groundwater beneath the site, as measured in a groundwater monitoring well just southwest of the gasoline UST, is approximately 47.3 feet below ground surface (bgs). Regional groundwater flow beneath the site is southerly. PROCEDURES Resources Jim Thorpe Oil conducted the excavation to remove impacted soil beneath the north end of the former gasoline UST on March 31, 2005. Joe Vasquez, a Ground Zero geologist, supervised excavation activities and sample collection under the direction of John Lane, CA Registered Geologist 6795. Mr. Harlin Knoll of EHD conducted a site inspection and observed sampling activities on March 31, 2005. Groundwater sampling was conducted by Anthony Scoma, an experienced Ground Zero technician on April 7, 2005. Mr. Jeffrey Wong of EHD conducted a site inspection and witnessed the groundwater sampling on April 7,2005. Argon Laboratories (DHS Certification #2359) conducted the laboratory analyses. More detail on site activities is provided below. Soil Excavation and Sampling Contaminated soil excavation and confirmation sampling occurred on March 31, 2005. Not counting clean overburden (pea gravel), approximately 30 cubic yards of soil was excavated by Thorpe. The dimensions of the excavation measured approximately 20 feet by 20 feet, and up to 18 feet deep. Evidence of contamination was noted in the northwestern portion of the excavation at depths between approximately 15.5 and 17 feet bgs. Photoionization detector(PID) readings ranged from 17-70 ppm at those locations. Excavation continued west and north, and to a depth of approximately 18 feet in the center of the excavation until PID readings decreased to less than 1.5 ppm. The excavated material was stockpiled on asphalt and covered by visqueen plastic pending characterization. Field procedures and field notes for excavation activities are included in Attachment B. Confirmation Soil Sampling Confirmation samples were collected from the excavation floor at a depth of approximately 18 feet bgs and from the south, east, west, and north sidewalls at depths of approximately 16, 15.5, 16.4, and 16.7 feet bgs, respectively. A 4-tube composite sample was collected from the stockpiled soil. Sample locations are shown on field notes (Attachment B, page B-4). The samples collected from the excavation were submitted under chain of custody to Argon Laboratories for analysis of G:\GROUNDZEUADIFire\excsum.doc