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.APR 2$ '98 02:50PM SMITH/ATC ASSOCIATES P.3 ' <br /> 'y I <br /> r <br /> obtained during the remediation and construction activities will help determine the location of the <br /> monitoring wells. <br /> The borings will be advanced to depths of approximately 30 feet using. a hollow stem auger <br /> equipped drill rig. Drift will be conducted by a State-licensed (C57) drilling company. Afield <br /> geologist will..be present to log drill cuttings and soil samples. Descriptions of soil types <br /> encountered and sample collection intervals will be recordtd on boringlwe111ogs. Soil samples <br /> will be collected at five=foot intervals or at changes in lithology, field screened with a PID, and <br /> selected soil samples from each of the three borings will be submitted for laboratory analysis. All <br /> drill cuttings will• be encapsulated with visqueen plastic and stored on site ponding laboratory <br /> results. <br /> • - ,�,,,YeN Con�rn�ction . <br /> The borings will be completed as groundwater moi.itoring wells. The monitoring wells will be <br /> - ' constructed o£'2-inch or 4-inch inside diameter schedule 40 PVC well- screen and casing. A <br /> 0.020-inch well screen slot and No. 8 SRI supreme sand pack will be used.• The well scieen will <br /> be placed at a depth of 5 feet above and 15 feet below the water table to allow for fluctuations: <br /> The sandpack will be placed to a depth of two feet above the,top of screen. Bentonite pellets, <br /> two feet in thickness,will be placed on top of the sand. Neat cement will be used to seal the wells <br /> in accordance With California Well Standards (December I981). To protect the integrity of the <br /> wells, locking, water-tight well plugs will be installed on each well and a water-tight wellhead <br /> •. labeled "monitoring well" will be concreted over each well. The top of casing of the new <br /> woWieads will be surveyed to assess groundwater gradient and flow direction. <br /> Rail-Sample Analysis <br /> Selected soil samples will be immediately placed on ice and delivered under chain-of-custody <br /> documentation-to a State-certified laboratory for analysis. Samples will be analyzed for TPHd <br /> and TPHg using EPA Method 8015 modified, $TEX using EPA Method 8020, and oxygenate <br /> Ebel-additives using EPA Method.8260. <br /> Well-Wyclummmusad GrundwaterSara lln <br /> Measurement of depth to water in all wells will be completed to evaluate the direction and <br /> rnagnitude of tine-groundwater gradient beneath the'site. The now wells will be developed using <br /> surge and bail techniques until the produced water is relatively sediment free. Prior to the <br /> ' collection of groundwater samples, a minimum of three well volumes (cuing and sand pack) will <br /> h6 purged. Temperature, pK water elevation, and electric conductivity Will,be measured and <br /> allowed to stabilize. Water samples will be collected using disposable bailers, one dedicated to <br /> . each well. <br /> Groundwater samples collected from all monitoring wells will be submitted using chain-of- <br /> custody record to a State-certified laboratory. Groundwater samples, three total, will be analyzed <br /> fvr TPHd, TPH& BTEX, and oxygenate fuel additives. Purge.water will be stored in 55-gallon <br /> drums approved for hazardous liquid storage pending laboratory analysis. <br /> isA822541wpadda d.doc 2 <br />