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r Mr. Harlin Knoll/San Joaquin County Environmental Health Division September 3, 2002 Page 2 On the day of sampling,the RAB Geologist will lead a "tail gate" safety meeting with the drilling contractor to review details of the Health & Safety Plan. Concrete cutting will be performed as necessary. All field sampling equipment will be clearted with a biodegradable detergent and triple rinsed with tap water prior to use. Soil Sampling The mobile GeoProbe sampling rig will be first positio ed over the marked location of B1 shown on Figure 2. Dual-tube sampling will be used to collec continuous undisturbed soil samples over four-foot drive intervals. Soil samples will be sub-sampled from the drive tube at depths of 13- 14', 18-19',and 23-24' (five-foot depth intervals beginiling at the bottom of the tank pit). Should diesel continue to be detected, probing will continiv e to a depth of 28-29' or stop at first groundwater. This information will be used to guide the sampling depth and TPHd testing in probes B2, B3 and B4. The soils will be logged by a Registered Geologist according to the Unified Soil Classification System (ASTM-2488 visual). A photoionization d tector will be used to test soils for the presence of volatile organic compounds. The soil sam les will be capped, labeled and placed in an ice-chest in preparation for transport under chain-)f-custody to McCampbcll Laboratory, a State Certified Laboratory located in Pacheco, Califoriii a. Groundwater Grab Sample At location B4, the groundwater down-gradient side o the release, the probing may continue to 29'to open the hole to groundwater. The depth of stan ling groundwater will be measured with a sounding meter. The sampling configuration will then be changed to collect a grab sample of groundwater through a temporary 1-inch diameter SCH 40 PVC casing with 0.020 machine slot. Groundwater is estimated to occur at a depth of about 2 ' bgs. 'The groundwater will be collected with a pre-cleaned mini-bailer and carefully poured into laboratory-supplied acidified 40 ml vials for volatile organic compounds and fuel oxygenates. Amber liter bottles will be used to collect groundwater for diesel analysis. The groundwater grab samples will be capped, labeled and placed in an ice-chest in preparation for transport under chain-of-custody to McCampbell Laboratory, a State Certified Laboratory located in Pacl eco, California. Backfill and Surface Restoration The probe holes will be filled by tremic, which will bc raised in increments as Portland Cement with bentonite is pumped to the base of the probe hole. The ground surface will be restored in a like-condition. Disposal Excess soil cuttings, sampling and cementing materials will be stockpiled onsite in a labeled steel drum pending disposal. Laboratory Analysis McCampbell laboratory will be requested to analyze the selected soil and water samples for Total Petroleum Hydrocarbons as diesel (TPHd) according to EPA Method 8015m and aromatic hydrocarbons benzene,toluene, ethylbenzene and xylen s (BTEX) and the fuel oxygenates (TBA, 1 I