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AI) I Environtnentel Assessment Report 2 • Chevron U S A Products Com an , 575 Wast Grantitne Road Tracy, CA June 29, 1995 drums Sod and drums were temporanly stored on site pending removal and disposal by Integrated Wastestream Management, Inc , of Milpitas,CA 2.3 Soil Sampling Sod samples were collected from boreholes MW-1, MW-2, MW-3 and MW-4 at 5-foot intervals during drilling, beginning at approximately 6 5 feet BGS Samples were collected using a 2 5-inch 0 D split-spoon sampler, lined with three 2-inch-diameter by 6-4nch-long brass sample tubes The sampler was driven 18 inches ahead of the augers at each sample point Sod samples were field screened for hydrocarbon vapors using a photo-ionization detector(PID) Sod encountered was logged using the Unified Sod Classification System by a Groundwater Technology field geologist working under the supervision of a California registered geologist(Appendix B) One sample tube from each 5-foot interval was sealed, labeled and placed on ice in an insulated container for transport under chain-of-custody manifest to Sequoia Analytical (Sequoia), a California state-certified analytical laboratory in Sacramento Sod samples collected at the 6 0-foot(6 5-foot for boring MW-3) and 11 5-foot depths from the borings were submitted for laboratory analysis Samples were analyzed for benzene,toluene, ethylbenzene i and total xylenes (BTEX), and total petroleum hydrocarbons-as-gasoline (TPH-G), using U S Environmental Protection Agency(EPA)methods 5030/8024/modified 8015 Samples from the • 6 0-and 11 5-foot depths from bonngs MW-1 and MW-4 were also analyzed for total hydrocarbons-as- diesel (TPH-D)via EPA methods 3550/8015 In addition to the above analyses, samples from the 6 0- and 11 5-foot depths from boring MW-1 were analyzed for total oil and grease via standard method 5520 C&F,for semi-volatile organics via EPA method 8270, and for the metals cadmium, chromium, lead, nickel and zinc A composite of sod stockpile samples was analyzed for BTEX,TPH-G,TPH-D, and total oil and grease using the methods described above 24 Groundwater Monitoring Well Installation and Development A groundwater monitoring well was installed in each of bonngs MWA,MW-2, MW-3 and MW-4 on May 2, 1995 The mondonng wells were constructed of 2-inch-diameter schedule 40 PVC blank casing and 0 020-inch slot well screen with flush threads Well screen was installed at a depth of 5 to 20 feet BGS in each well A#3-sand filter pack was installed in the annulus from the bottom of each borehole to 1 5 feet above the top of the well screen, followed by a well seal consisting of a 1 5-foot thick bentonite layer overlain by neat cement(grout) to ground surface Each well was secured by a locking expandable well cap and fitted wrth a traffic-rated well box set in concrete Details of well construction are presented on the drilling log (Appendix B) Figure 1 shows the location of wells relative to former relevant station structures • 013SEAR APTIChv-112) ❑❑`� QRC& WATER