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v • Some minor changes to this approach were made during the field sampling and in consultation with the SJC EHD representative as the work proceeded as noted below 1.0 Field Methods - Exploratory Barings and Field Modifications Four exploratory bonngs were drilled at the locations shown on Figure 1 Drilling permits were secured from SJC EM, and a subsurface utility clearance was performed prior to doing the fieldwork The boreholes were drilled with hollowstem auger truck mounted drilling equipment All drilling equipment and sampling tools were cleaned pnor to arriving, and before leaving the site The sampler was advanced collecting soil samples at five-foot intervals in each borehole. Soil samples retained for chemical analysis were contained from the liners at depths of suspected or obvious contaminant gsence Once retrieved and dissembled, the soil filled brass liner was removed and the ends wNe sealed with Teflon paper or foil and plastic endcaps, labeled, logged onto sham-of- custody forms and placed on crushed ice in a chilled ice chest The boreholes were logged usmg the Unified Soil Classification System under the supervision of a registered geologist Additional lithologic information was collected to describe the subsurface geology Soil samples will be collected for analysis at five-foot intervals, at intervals of obvious contamination and possibly at stratigraphic features of interest Upon completion of the borehole drilling and collection of soil samples, depth to groundwater measurements and water samples, the boreholes were sealed per the pemnit requirements by backfilling with cement grout mixed the SJC EHD specification,placed from the bottom to top of each borchole with a trernte prpe Driff soil • cuttings,decontamination and grout water were labeled and drummed and placed on-site at a client- designated lientdesignated storage location 1.1 F eld Modifications to Work Plan Wright had initially attempted to sample the site using a Geoprobe drilling rig However the presence of a -relatively thick, cemented soil horizon caused GecrProbe refusal -so a hollowstem auger drill was used to drill the borings Due to the cemented soil, continuous sampling was not practical so five-foot interval sampling was substituted Reconnaissance soil vapor measurements were to have taken with a portable organic vapor Photoionization Detector (PID), however the PID was not delivered to the site in time for drilling. Wright searched for field indicators of contaminants (stains and odor) in each soil sample and in drill cuttings Boring B-4 was moved mward toward the tank pit dine the presence cif a naturra-1 gas hire that utility -marlong; had only partially marked The boring location movement was discussed and approved in consultation with the SJC EHD representative 2.0 Field Methods—Reconnaissance Groundwater Sampling A groundwater sample was collected from each borehole A brief summary of the sampling procedure follows Each borehole was advan the aquifer and temporarily cased for sampling Depth to groundwater measurements made to the nearest one-one hundredth of one foot, and also checked for the presence of separate phase product The water entering the borehole was sampled using a clean haul line and PVC disposable bailer, and carefully poured into the appropriate laboratory prepared contemner with rmmmurn cavitation Each wager sample was labeled,logged onto a chain-of-custody form, and placed in a chilled ice chest for transport to the . laboratory Page 2 of 6