SITE INFORMATION AND CORRESPONDENCE_FILE 1

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December 19, 1986 Harding Lawson Associates 4167,154.02 Exxon Company, U.S.A. Mr. Kent Sanderson Page 3 used the data to evaluate the vertical extent of hydrocarbons. Soils were removed to an approximate total depth of 20 to 21 feet below grade, which was the maximum capability of the backhoe equipment provided by AEMC. Ground water was observed in the excavation at this depth. Seven soil samples (EX-1 through EX-7) and one ground-water sample (GW-1) were collected on September 23, 1986 from the deepened excavation floor. Soil was brought to the surface by means of a backhoe bucket and sampled using an Alconox-cleaned stainless steel tube. After the cuter 3 inches of exposed soil had been removed, the sample tube was filled completely, capped with aluminum foil and a plastic slip cap at each end, sealed with tape, labeled, and stored on ice until delivery under chain of custody to a state-certified laboratory. Each of the seven soil samples were ana- lyzed for total petroleum hydrocarbons (TPH) using a gasoline standard to a detection limit of 10 parts per million (prm) and for benzene, toluene, and xylene (BTX) to a detection limit of 0.05 ppm by EPA Method 602. All samples were analyzed by Analytical Science Associates (ASA) of Emeryville, California. Ground-water sample GW-1 was collected stainless steel bailer and was decanted from within the excavation using ainto two laboratory-prepared volatile organic analysis vials, filled completely to eliminate any void space, capped with a Teflon-lined cap, labeled, and stored on ice until delivery to ASA the same day. Sample GW-1 was analyzed for TM using a gasoline standard to a detection limit of 50 parts per billion (ppb) and for BTX. to a detection limit of 1 ppb using EpA Method 602. Ms. Laurie Cottulla of the S7CLHD was present ming the roil excavation and sampling. Soil Aeration and Sampling procedures A total of 300 cubic yards of excavated soils were aerated on site between September 9, and November 21, 1986 in accordance with the requirements of the S7CAPD. Prior to aeration, stockpiled soils were vapor-surveyed using an OVA at a minimum, of 12 locations per 50 cubic yards of soil. Vapor survey locations were recorded on a field map and vapor readings were tabulated. Soil samples were collected from 18 inches below the exposed stockpile surface at the four "worst casept locations for each 50 cubic yards and were comoosited. The six composited samples were ana- lyzed by ASA for TPH using a gasoline standard. An Alccnox-cleaned stainless steel tube was advanced into the soil and comp cted until c letely filled, carcec3 with altsninum foil and plastic slip caps, sealed with tape, labeled, and stored cn ioe until delivery under cl^ain of custody to ASA.