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C\TATC <br /> A S S O C I A T E S I N C <br /> located in the immediate vicinity of boring FPB-2, which contained free product; one boring will <br /> be located approximately five feet north of boring SB4; and one boring will be located <br /> approximately five feet west of boring S136. 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, traffic <br /> rated wellhead labeled "monitoring well" will be concreted over each well. Proposed well <br /> construction details are shown on Figure 3. The top of casing of the new wellheads and all <br /> existing wells will be surveyed to assess groundwater gradient and flow direction. All drill <br /> cuttings will be stored on site in 55-gallon drums pending laboratory results. <br /> Sample Analysis <br /> Selected soil samples, at least two from each boring, will be immediately placed on ice and <br /> delivered under chain-of-custody documentation to a State-certified laboratory for analysis. <br /> Samples will be analyzed for total petroleum hydrocarbons as gasoline (TPHg, EPA Method <br /> �-- 8015), benzene, toluene, ethylbenzene, and xylenes (BTEX, EPA Method 8020), and oxygenate <br /> 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, six 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 /> w:\17861\repotls\wkpweLdoc 3 <br />