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(YVATC <br /> A S S O C I A T E S I N C <br /> well will be located near soil boring SB6, one boring will be located near soil boring SB3, and one <br /> boring will be located near soil boring SB5. The estimated groundwater flow direction is to the <br /> northeast. Proposed well locations are shown on Figure 2. <br /> Groundwater Monitoring Wells Construction Details <br /> The three soil borings will be completed as groundwater monitoring wells. The monitoring wells <br /> will be constructed of 2-inch inside diameter schedule 40 PVC well screen and casing. A 0.020- <br /> inch well screen slot and#2/12 mesh sand pack will be used. Neat cement will be used to seal the <br /> wells in accordance with California Well Standards (December 1981). To protect the integrity of <br /> the 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. Proposed well construction details <br /> are shown on Figure 3. The top of casing of the new wellheads will be surveyed to assess <br /> groundwater gradient and flow direction. All drill cuttings will be stored on site in 55-gallon <br /> drums pending laboratory results. <br /> 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 total <br /> petroleum hydrocarbons as gasoline (TPHg, EPA Method 8015), benzene, toluene, ethylbenzene, <br /> �.. and xylenes (BTEX, EPA Method 8020), and oxygenate fuel additives(EPA Method 8260). <br /> Well Development and Groundwater Sampling <br /> Measurement of depth to water in all wells will be completed to evaluate the direction and <br /> magnitude of the groundwater gradient beneath the site. The new 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 (casing and sand pack) will <br /> be purged. Temperature, pH, 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 /> for TPHg, BTEX, and oxygenate fuel additives. Purge water will be stored in 55-gallon drums <br /> approved for hazardous liquid storage pending laboratory analysis. <br /> Report Preparation <br /> Upon completion of the well installation and development activities, a summary report will be <br /> prepared for submittal to PHS/EHD. The report will include a description of all field activities, <br /> laboratory analytical results, and well/boring logs. <br /> wA14981\reportc\wkpwel.doc 3 <br />