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(VYAT4L <br /> A S S O C I A T E S I N C <br /> t ' <br /> field geologist will be present to log all drill cuttings and soil samples. Each soil sample will be <br /> field screened with a Photoionization Detection (PID) meter or similar instrument and at least two <br /> samples from each of the two borings, based on field observations (i.e. odor, discoloration, PID <br /> readings), will be placed in a cooler with ice and submitted for laboratory analysis. <br /> Placement of Borings and Wells <br /> To evaluate the lateral extent of impacted soil and groundwater, one boring will be located <br /> southwest of well MW1 and one boring will be located south-southeast of well MW1. The <br /> groundwater flow direction is to the northeast. Proposed boring locations are shown on Figure 2. <br /> Because we are trying to define the horizontal extent of impacted soil and groundwater, if <br /> impacted soil is encountered during the advancement of the initial soil borings, the borings will be <br /> terminated and grouted to the surface. ATC will then "step out" further southwest or south-. <br /> southeast and advance another soil boring(s) until clean soil and groundwater are encountered. <br /> Groundwater Monitoring Wells Construction Details <br /> The borings will be completed as groundwater monitoring wells. The monitoring wells will be <br /> constructed of 2-inch inside diameter schedule 40 PVC well screen and casing. A 0.020-inch well <br /> screen slot and #2112 mesh sand pack will be used. Neat cement will be used to sea] the wells in <br /> accordance with California Well Standards (December 1981). 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. Proposed well construction details <br /> are shown on Figure 3. The top of casing of the new wellheads will be surveyed and tied into the <br /> existing groundwater monitoring wells to assess groundwater gradient and flow direction. All <br /> drill 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), total petroleum hydrocarbons as diesel (TPHd, EPA Method 8015), benzene, toluene, <br /> ethylbenzene, and xylenes (BTEX, EPA Method 8020), and oxygenate fuel additives''(EPA <br /> Method 8260). <br /> Well Development and Groundwater Sam lin <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, MW4 and MW5, will be <br /> developed using surge and bail techniques.until the produced water is relatively sediment free. <br /> Prior to the collection of groundwater samples, a minimum of three well volumes (casing and sand <br /> pack) will be purged. Temperature, PH, water elevation, and electric conductivity will be <br /> wAI3099Veportslwkpwelii,doe 3 <br />