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Site Background Information - Grewal's Market Page 5 of 6 I • August 2007 - A vapor intrusion investigation was conducted at the site by advancing two soil-vapor borings (P-13 and P-14) to five feet bsg. Laboratory analysis of soil-vapor samples did not detect any constituents of concern. Analytical. results of soil-vapor samples are summarized in Table A2. Results of the August j 2.007 investigation were reported in AGE-prepared Soil Vapor Investigation Report, dated 10 December 2007. • April 2008 - Three CPT soil borings (P-15, P-15B and P16) were advanced to maximum depths of 100 feet bsg to assess the off-site lateral and the vertical extent of petroleum-impact and to-identify potential hydrogeologic units. Based on CPT data, AGE interpreted the CPT data to identify the vadose zone (0 to 40 feet) and four potential hydrogeologic units informally identified as Hydrogeologic Units 1, 2, 3 and 4 at depths between 45 to 63 feet bsg, 63 to 72 feet bsg, 72 to 80 feet bsg and 80 to 95 feet bsg, respectively. Laboratory analysis of the P156-65 to 75 foot grab water sample detected TPH-g at a concentration of 800 pg/l. No other contaminants of concern were detected. Analytical results of grab water samples are summarized in'Table Al. A report of findings (Cone Penetrometer Testing Site Investigation - Second Quarter 2008, dated 14 October 2008) was submitted by AGE to the SJCEHD SOIL PROPERTIES Based on vertical soil profiles in soil-boring logs acquired to date during site assessment activities, a very stiff to hard,fine grained sandy SILT was.generally encountered at depths ' between 10 feet and 25 feet bsg, between 40 feet and 50 feet bsg and between 60 feet and 65 feet bsg. A medium dense to dense, silty fine SAND was generally encountered at depths between 25 feet and 40 feet bsg, between 50 feet and 60 feet bsg and at depths greater than 65 feet bsg. Permeability and porosity characteristics were tested at 35 feet bsg and at 55 feet bsg in soil samples collected at the site in February 2002 (Quarterly Report_ First Quarter 2002, dated 17 July 2002). Analysis of the 35 foot soil sample reported an average permeability in a clayey sand (lower vadose zone) at 3.0 x 10-6 cm/s,.'porosity at 40 percent and moisture at 23 percent. Analysis of the 55 foot soil sample reported an average permeability in a silty clay with sand (upper hydrogeologic unit 1) at 6.0 x 10-6 cm/s, porosity at 49 percent and.moisture at 34 percent. Physicochemical & microbial characteristics were tested .at 40 feet bsg in a soil sample collected at the site in February 2002 (Quarterly Report-First Quarter 2002, dated 17 July 2002). Analysis of the 40 foot soil sample reported the general microbial enumeration was 9.9 x 105 CFU (colony forming units) per gram, and hydrocarbon degrading microorganisms were present at 1.2 x 105 CFU, or approximately 12.12 percent of the Advanced CeoEnviranmental,Inc.