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ATC Associates Inc. <br /> M&TC <br /> 1117 Lone Palm Avenue,Suite 201 <br /> Modesto,California 95351 <br /> 209-579-2221 <br /> fax:209-579-2225 <br /> AS $ 0CIATE $ INC. <br /> boring will be advanced to approximately 80 feet bgs. Previous subsurface investigation <br /> activities using CPT methods have indicated three potential water bearing zones, each separated <br /> by clay or silty clay. ATC will generally be targeting the intermediate water bearing zone <br /> previously identified between 35 and 45 feet bgs and the deeper water bearing zone identified <br /> between 65 and 75 feet bgs. Actual targeted water bearing zones will be based on the CPT <br /> sounding log provided during the proposed drilling activities. <br /> After the subsurface materials have been characterized and evaluated, a field geologist will select Soo'JS <br /> sample depths for collecting discrete groundwater samples. For each discrete sample, a direct -t1µ <br /> push Hydropunch boring will be advanced adjacent to the initial CPT boring and a groundwater <br /> sample will be collected from the selected deeper water bearing zone. Following the collection j <br /> r <br /> of groundwater samples, the boring will be grouted to the surface with a neat cement slurry .� .. •� � <br /> mixture using a tremmie pipe. ATC estimates a minimum of two groundwater samples will be (Irl <br /> collected from the boring after evaluating the CPT log for potential water bearing zonestx <br /> separated by suspected overlying aquitard and/or significant clay layers. <br /> Groundwater samples will be collected using Hydropunch° type groundwater sampling system. <br /> The system includes an expendable drive point attached to poly vinyl chloride (PVC) or stainless <br /> steel filter screen threaded onto the leading end of the direct push rods. While the sampler is <br /> advanced, O-ring seals and the expendable drive point will provide a watertight system to ensure <br /> sample integrity. <br /> When the Hydropunch® type groundwater sampling system has been advanced to the desired <br /> depth, the expendable drive point is held in place by the surrounding soil while the direct push <br /> rods are retracted. Once retracted, up to 60-inches of PVC or stainless steel filter screen with slot <br /> sizes of 0.010 inches will be exposed allowing for groundwater infiltration. A stainless steel <br /> bailer will be lowered inside the hollow push rods until it is immersed in groundwater. <br /> Following soil characterization and groundwater sample collection, the boring will be backfilled <br /> with neat cement grout to the ground surface. Drill cuttings, if any, will be stored on-site in 55- <br /> gallon drums pending laboratory results. <br /> Sample Analyses <br /> Selected soil and groundwater samples collected during the advancement of the soil borings will <br /> be submitted under chain-of-custody procedures to a California State-certified analytical <br /> laboratory. The soil and groundwater samples will be analyzed for total petroleum hydrocarbons <br /> as gasoline (TPHg) or gasoline range organics (GRO) utilizing EPA Method 8015B; and <br /> benzene, toluene, ethylbenzene, and total xylenes (BTEX), methyl tertiary butyl ether (MTBE), <br /> tertiary butyl ether(TBA), and tertiary amyl ether(TAME) utilizing EPA Method 8260B. <br /> SA\Environmenta1\25847\37 Tracy\Reports\Response 2009 Aug.doc 6 <br />