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'—' Geological Ted uacsJKc. Page 2 GeoProbe Installation Report Cardoza(Louise) Project No. 1135.2 June 15,2004 Irrigation District, identified a water main running through the proposed borehole location area. The locations were adjusted to avoid the water main. The GeoProbe system advances a coring tool with a pneumatic hammer to a selected depth. Upon reaching that depth the coring tool is opened and advanced further to fill the core barrel. The soil sample enters an acetate cylinder contained in the coring tool. Upon filling, the coring tool is pulled from the hole and the cylinder is removed. The cylinder is then cut and the selected interval is capped with Teflon end caps and placed on ice for shipment to the laboratory. The remainder is used for geologic logging. Monitoring well permits were secured from the San Joaquin County Public Health Services/Environmental Health Department (SJC PHS/EHD). The local regulatory agency was notified 48 hours prior to commencing work. The boreholes were filled with a neat cement grout under the supervision of SJC PHS/EHD staff. 2.1.1 Soil Sampling Procedure Soil samples were collected for geological and laboratory evaluation at five-foot intervals from ground surface to total depth. A boring log providing sediment description using the USCS and field observations was maintained by a professional geologist working under the supervision of a registered geologist. Soil samples were collected in 2.0-inch acetate cylinders. All soil samples were sealed with end caps, labeled, and placed in a cooler at 4° Celsius for transport to the laboratory following Chain of Custody protocol. An OVM was used to screen the soil samples. Details on the geology encountered during the completion of the soil sampling as well as the field observations are included in Section 3.2, Geology and Field Observations. 2.1.2 Soil Sample Laboratory Analyses Soil Three soil samples from each borehole (including one from the capillary fringe) were `r submitted to Sequoia Analytical of Sacramento, California (State Certified Laboratory #1624) for the following analysis: • Benzene, toluene, ethylbenzene and xylene(BTEX)by EPA method 8020. • Gasoline range petroleum hydrocarbons (TPH-G)by EPA method 5030/8015(m). • Gasoline oxygenates (MTBE, DIPE, ETBE, TAME and TBA)by EPA method 8260. • 1,2 DCA& EDB by EPA method 8260. A chain of custody was completed for all samples submitted and tracked to ensure sample .r integrity. 2.2 Groundwater Sampling To investigate the presence of gasoline-range petroleum hydrocarbons in the groundwater at this site, grab groundwater samples were obtained from each borehole. V & W Drilling staff used 3/8" tubing and ball check valves to lift the water samples to the surface. The samples were carefully poured from the tubing into VOA vials. The VOA vials were capped, inverted, tapped, and checked for headspace bubbles. Some trace headspace (bubbles) was noted in the VOAs as groundwater mineral constituents effervesced when