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_ a — Pal <br /> tt <br /> A <br /> F <br /> YX <br /> Ted Knowles <br /> February 6, 1969 <br /> 202/799-5027.04 <br /> below grade. The samples will be obtained using25-inch <br /> a . 0.A. <br /> split-spoon sampler, lined with three 2--inch diameter by 6-inch <br /> tst <br /> long brass sample tubes. The sampler will be driven 18 inches <br /> ahead of the augers at each sample point. Each sample will then <br /> } be field screened by visual observation and with a photo- <br /> ionization detector (PTD) . The collected samples will be sealed, <br /> k capped, and placed on ice in an insulated cooler. Field-screened <br /> samples that show potential contamination- urination will be delivered to an <br /> f; <br /> p° analytical laboratory accompanied by a Chain-of-Custody manifest. <br /> (> The purpose of these samples is not only to obtain additional <br /> information about the extent and concentrations of hydrocarbons in <br /> soil, but to confirm subsurface soil condition3 (lithology) . <br /> Samples submitted for laboratory analysis will be analyzed for TPH <br /> F! as gasoline and BTEK by modified EPA Method 5030/8015/8020. Soils <br /> Y F4 <br /> generated during the drilll,ng process will be stored on site in <br /> �Pt rd AOT approved drums for disposal ata later date. <br /> }., <br /> r <br /> Four vapor extraction wells will be installed within the soil <br /> to <br /> borings✓ 'd �a g . provide access for long-term air sampling. Approxi- <br /> mately 35 feet of. 4-inch diameter PVC well screen (0.020-inch <br /> L machine slotted) , and approximately 10 feet of blank casing to <br /> surface will be used for construction of the four vapor extraction 4 <br /> �t <br /> wells. The total depth of yells will ba approximately .45 feet: <br /> The annulus will bt, filled with a. sand pack composed of washed #2 <br /> t <br /> Lonestar Lapis Lustre sand extending from the bottom of the <br /> hart ;� borings to a point approxImatel.y 2 feet above the screened <br /> interval. The wells will then be finished with a bentonite seal <br /> ;n and sand-cement. <br /> grout to surface. Each well head will be mani- _ <br /> folded into a central vacuum unit by..trenching and piping from <br /> t <br /> each well to the treatment compound, The well heads and as- <br /> soclated hardware would be set .below grade within a traffic-rated <br /> rc <br /> } ' street vault (Figure <br /> r� x: 19 <br />