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• 4 <br /> Appendix A - Site Background Information <br /> Former Fisco Warehouse <br /> Page 3 of 7 <br /> Hydrostrati graphic Unit 3 (HU3)extends from 96 feet bsg to and possibly beyond 134 feet bsg. Silt <br /> and clay are the dominant soil type in the interval, though sand is present. The interval is <br /> characterized by pore pressure variations from moderate to high pressures. <br /> Hydrostrati graphic units are depicted in cross sectional views A-A' and B-B'. <br /> PREVIOUS SUBSURFACE INVESTIGATION <br /> On 18 September 1997,five soil probe borings (B1 through 135)were advanced at the site to assess <br /> the lateral and vertical extents of petroleum-impacted soil.Total petroleum hydrocarbons quantified <br /> as gasoline (TPH-g) were detected in samples from Bi, B3, and B5 at concentrations as high as <br /> 14,000 mg/kg.Benzene was detected in only one sample(B 1-40),at a concentration of 0.042 mg/kg. <br /> Toluene,ethylbenzene,and xylenes were detected in samples from B 1,B3,and B5 at concentrations <br /> as high as 1,600 mg/kg(xylenes in 135-25). TPH-d was detected in samples from B 1,B3, and B5 at <br /> concentrations as high as 12,000 mg/kg (133-10 and B3-15). None of the samples analyzed from <br /> borings B2 or B4 contained detectable concentrations of TPH-g, TPH-d, volatile aromatic <br /> compounds benzene, toluene, ethylbenzene, and xylenes (BTEX), or methyl tertiary-butyl ether <br /> (MTBE). <br /> From 22 to 24 February 2000, four soil borings (MW-1 through MW-3 and 136) were advanced at <br /> the site. TPH-g was detected in nine of the 16 soil samples analyzed at concentrations as high as <br /> 6,700 mg/kg;TPH-d was detected in seven of the 16 soil samples analyzed at concentrations as high <br /> as 5,800 mg/kg. Benzene was detected in four of the 16 samples at concentrations as high as <br /> 0.027 mg/kg. Toluene, ethylbenzene, and xylenes were detected in eleven of the 16 samples at <br /> concentrations as high as 370 mg/kg. MTBE was not detected in any samples analyzed. Petroleum <br /> hydrocarbons were not detected in five of the 16 soil samples analyzed. <br /> In February 2001, four pilot soil borings were advanced at the site. Pilot borings MW-4 through <br /> MW-7 were completed as groundwater monitoring wells using two-inch diameter PVC casings with <br /> 0.020-inch slotted screens installed from approximately 60 feet to 40 feet bsg and with blank casing <br /> extending to the surface. A total of 16 soil samples were analyzed for TPH-g, TPH-d, BTEX, <br /> 1,2-dibromoethane(EDB), 1,2-dichloroethane(1,2-DCA),and the suite of five fuel additives.None <br /> of the analytes were detected at or above laboratory reporting limits in the soil sample analysis. <br /> On 10 and 11 January 2002, three soil boring (CPT-1, CPT-2, and CPT-3) were advanced on-site <br /> utilizing CPT technology to model the geologic and hydrogeologic framework and to assess potential <br /> dissolved petroleum migration pathways beneath the site. Soil borings CPT-1, CPT-2, and CPT-3 <br /> were advanced vertically to total depths of 96 feet bsg, 134 feet bsg, and 125 feet bsg, respectively, <br /> utilizing a 25-ton truck-mounted CPT drill rig equipped with 1.50-inch diameter hollow-stem rods. <br /> Advanced GeoEnvironmental,Inc <br />