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J hti � , r I •. ' I i II I t File No.2070.2 191kcembcr 1991 Page 6 i pumping test, the pump was slopped and the pumped well was allowed to recharge. A computerized data logger was used to continuously record the recharge level in the purnping well. A handheld groundwater probe was used to measure the recharge in the obsmaron wells, 1.0 RES';]LTS QF INVEST►GAT QN 3.1 Subsurface Soil Profile Extrapolation of data obtained dur.in,:; the advancement of soil borings 90-1 and 90-2 enabled an interpretation of the subsurface soil p:ofile to be determined. Figure 7 illustrates a lithologic cross section for the areas near the 1987 tank excavations. According to the lithologic cross section, clay. and silt comprise the majority of the .-mbsurface soil Fn the vicinity of the 1987 tank excavations. Several discontinuous and "pinched-ou;' Ienses of sand also exist in the vicinity of the 1987 tank excavations. This corresponds closely'A subsurface condHons ,ioted in the boring logs for the entire area of this investigation. 3.2 Local Groundwater Well Influence "Survey We conducted a research survey of groundwater wells located within 2,000 feet of the Rainho Bakery to determine their possible influent, on the subject property wells. According to documents on file with the State of California Department of Water Resources, three wells existed within a 2,000 feet radius of the Rainbo Bakery a,�, the time of our investigation. All three wells were located south of the subject property (see j`ibllre 8). Well A was installed to a depth of 217 feet in 1960 for irrigation purl3�ses. Well B w4:'Installed to a depth of 220 feet in 1963 for irrigation purposes, Well C was installed to a depth r,f 84 feet in 1949 for irrigation purposes. According to this s=ey, IIlta two wells id"losest proximity to the subject property are both pumping from a deep agpif'er approximately 220 feet below the surface and subsequently approximately 450 feet deeper than the Rainbo Bakery wells. Although we could not identify the screened interval of these weds from the well log documents, we feel that these wells,under normal pumping conditions, should not influenco the Rainbo Bakery wells. Well C, while shallow enough to potentially influence the Rainbo Bakery we!ls,appears to be far enough away so as to minimally influence the s•lbject proparty wells under normal pumping conditions. 3.3 Soil Analytical Laboratory Results, Soil sLmples obtained from the Rainbr: Bakery site were analyzed for the presence of total petroleum hydrocarbons (TPH); aromatic volatile organics (AVO's) and lead as ped recommendations in the 'Tri-Regional guidelines published by the Regional Water Quality Control Board. Table I summarizes the analytical laboratory results for this soil samples obtained at the subject property, Figurt; 9 illustrates the lozations where the soil samples were obtained and their '~ corresponding contaminant concentrations. Copies of the anal)lical laboratory results for the soil samples are included a,1 Appendix Vill. ANDERSON I; CONSULTING 2A, Gnoup 1