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07/ 16/ 1999 14 : 04 209-579-2225 MODESTO ATC PAGE 06 <br /> 5 <br /> C/A <br /> Groundwater Sampler will be threaded onto the leading end of the Geoprobe when the <br /> groundwater is encountered. While the sampler is advanced, O-ring seals and an expendable <br /> drive point will provide a watertight system to ensure sample integrity. <br /> When the tool has been advanced to the desired depth, extension rods will be sent downhole to <br /> brace the bottom of the sample screen as the tool casing is retracted. When the casing is <br /> retracted, up to 414nches of screen with slot sizes of 0.004 inches will be exposed. Teflon <br /> tubing with a check valve attached to one end will be inserted down the casing until it is <br /> I <br /> mmersed in groundwater. Water will then be pumped through the tubing and to the ground <br /> surface by oscillating the tubing up and down. <br /> Following soil and groundwater sample collection, the borings will be backfilled with neat <br /> cement grout to the ground surface. All drill cuttings, if any, will be stored on-site in a 5-gallon <br /> container pending laboratory results. <br /> Samnle Anslysis <br /> Selected samples will be immediately placed on ice and delivered under chain-of-custody <br /> documentation to Sequoia Analytical (ELAP 41210), a State-certified laboratory, for analysis. <br /> Soil samples will be analyzed for total petroleum hydrocarbons as gasoline (TPHg) and total <br /> petroleum hydrocarbons as diesel (TPHd) using EPA Method 8015 modified and benzene, <br /> toluene, ethylbenzene, and xylenes (BTEX) using EPA Method 8020. Groundwater samples will <br /> be analyzed for TPHg, TPHd, BTEX, and oxygenate fuel additives using EPA Method 8260. <br /> Report Preparation <br /> Upon completion of all field activities, a summary report will be prepared for submittal to <br /> PHS/EHD. ATC will prepare a report that will include a description of all field activities, <br /> laboratory analytical results, boring logs, and recommendations. <br /> i <br /> All work described in this workplan will be performed under the direction of a California <br /> Registered Professional Engineer. A completed Site Safety Plan (SSP) is contained in <br /> Attachment I and a Quality Control/Quality Assurance Plan is contained in Attachment 2. All <br /> field work will be completed in accordance with these plans. <br /> Projected Sehedule <br /> Once PHS/EHD approval of this workplan has been received, ATC will obtain the necessary <br /> i permit from the Reclamation District, and schedule drilling activities. It is anticipated the <br /> drilling will be completed in one day and drilling has been tentatively scheduled for September <br /> 1998. ATC will notify PHS/EHD at least 48 hours prior to beginning any field activities. The <br /> summary report will be submitted to PHS/EHD approximately four to five weeks after the <br /> completion of field activities. <br /> w:k62514tnpoe1sAwkp.dae 4 <br /> I.I <br />