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•� Apci128, 1995 95-1104802 80 Hinaman Trust Attention Mr David Chinchen Subject REPORT - Preliminary Subsurface Investigation 2409 East Main Street Stockton, California Page 3 the boreholes Soil cuttings were placed into three 55 gallon DO T drums, labeled, and temporarily stored near the eastern margin of the site Subsurface Conditions Fill materials encountered during drilling included clayey soil and concrete rubble The concrete rubble was encountered within the former UST area, below clayey fill material at a depth of 2 to 3 feet below ground surface (bgs) Clayey fill was identified in the pump island (3 feet bgs) and hydraulic lift areas (7 5 feet bgs) The native soil at the site consists of moderate brown, damp, moderately plastic clay Six boreholes were drilled in the former UST area in an attempt to collect native soil samples from below the former UST locations (proposed depth of 12 to 13 feet) MARK was not able to collect these samples from the proposed depth due to the presence of concrete in the backfill material The concrete prevented drilling beyond a depth of 2 to 3 feet Because of this limitation only two soil samples were collected Sample B2 was collected from a depth of approximately 3 feet in the southern portion of the former UST area PID readings [110 parts per million (ppm)] and a gasoline odor were noted during the collection of sample B2 Sample BI-G was collected from a depth of 13 feet, in native soil on the south side of the former UST location after encountering multiple drilling refusals (shown on Drawing 2) 1 in the concrete rubble fill materials The sample depth and Iocation were chosen to characterize native soil conditions at a depth below and adjacent to the former USTs Soil cuttings from the remaining boreholes had PID readings generally ranging from 17 to 7 3 ppm These samples did not appear impacted with petroleum hydrocarbons and the PID readings are probably indicative of background soil conditions ' Groundwater was not encountered during drilling at any of the locations investigated The depth to groundwater at the site is estimated to be deeper than 50 feet bgs Laborato1y Anal cal Results i The soil sample analytical results, including sample depth and location are summarized in Table 1 Samples from the waste oil tank area and from the hydraulic lift area were analyzed I