ARCHIVED REPORTS XR0009854 - Laserfiche WebLink

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Groundwater was encountered at about 10-feet below grade A limited area of the excavation was advanced below groundwater occurrence Sod samples were collected from the excavation sidewalls and bottom, and soil stockpile by pressing a clean brass liner into the soil to a depth of about one foot, completely filling the liner Sample locations and approval was discussed with a representative of the PHS-EHD The liner was removed, sealed, labeled, logged onto a chain-of-custody forms and packed in a chilled ice chest for transport to the laboratory Soil was logged using the Unified Soil Classification System under the supervision of a registered geologist using the attached Sampling Protocol Approximately 505 15 tons of soil was properly removed to Altamont Landfill in Livermore, CA, a Class 11 waste disposal facility (see References) Upon completion of the excavation work, the excavation was backfilled to within four feet of ground surface with approximately 270 ton of 314" crushed rock The backfill work was then finished with 181 tons of a Class 11 backfill material to within 3 inches of the ground surface, compacted and the surface was repaved with asphalt Subsurface Conditions Exploratory soil borings were advanced on-site by previous investigators at the locations shown on Figure 1 The site is underlain by clayey soils, which locally contain thin fine grained sand laminae Clayey sand and silty sand beds occur at depths of about 8-feet and appear relatively thin and discontinuous These are underlain by clay strata below 14- to 16-feet deep These same shallow strata were observed during excavation Groundwater was encountered at depths of about 10-feet, and water appeared to be unconfined Data collected from existing groundwater monitoring wells has shown that the shallow groundwater historically flows in a northerly direction (see Figure 1) Chemical Analysis and Results Nine soil samples were analyzed at a State certified analytical laboratory Selected samples were tested for the following, Total Petroleum hydrocarbons as Gasoline (TPHG), Total Petroleum Hydrocarbons as Diesel (TPHD), Benzene (B), Toluene (T) , Ethylbenzene (E), Xylene (X), and Lead using EPA Methods 3550, 351018015, 5520, 8020 and 6000 The analytical reports are attached and results are listed below i n Table 1 Page 2