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�' ic..sty �.1 .- a�. { 1 13 ,July 1992 (GeoAudit CV 55-59 E2-1.32) Page 3 of 8 Samples arere transmitted to WEST laboratories for analysis. All samples were analyzed for the presence of heating oil in accordance with EPA method 8015 modified for diesel. Selected samples were also analyzed for the presence of volatile hydrocarbons (BTEX compounds) in accordance with method 8o20. The required detection limits for TPH were obtained, but high levels of motor oil and a diesel contamination interfered With the detection of BTE&X � compounds, raising the detection limit from the require 50.005 mg/kg to I mg/kg in SB-1 and SB-2 and to 0.05 mg/kg he chain-of-custody documents are attached to this report. 3.3 SUBSURFACE STRATIGRAPHY Figures 3 and 4 illustrate the shallow stratigraphy at the site. tions ishown in Fiure 2- All The location of these cross sec senetrated very similar borings are relatively close together and p materials. From the surface to a depth of e-10feet, most boorted penetrated medium yellow-brown to dark-brown, generally fine-grained to very fine-grained top eofSa��f' A thin grave ew borings, an 1-sand-clay lens was present near the top representsnbackfill retmaterial. inma clay few samples. orclay clasts were also observedauger Boring SB-4 and borings SB-6 through SB-8 penetrated a thin bed of brown silt from about 10 to 12 feet. This bed is present at SB- milar bed is approximately the same depth in SB-1 and bad was not g and a sreco nized in present in SB-5 at about 5-7 feet. This a.i SB3, but this may be due to the fact that only a 5-inch sampTeniy _ obtained because of sampling problrms. The silt bed is app somewhat consolidated, causing drilling rates to decrease through this interval. From about 12 to 18 feet, all borings penetrated medium to light- brawn or light yellow-bro wn fine to medium-grained sand. This bed was locally oxidized to reddish-brown. Coarse-grained, gray, unweathered granitic sand is present at a depth of approximately 18 feet. This sand is very well sorted and much coarser grained than the overlying units. Barings 58-2, SB-3, SB-5, and SB--7 recovered light yellow-brown silt at a depth of 25 feet; the deepest boring, SB_7, was_st .11_ n this bed at the total depth of 30 feet.