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} . <br /> y-I GASCO Oil Company December 11, 1990 <br /> t Quote No. 811 SG(Revised) Page 2-1 <br /> 1 SECTION 2 <br /> SCQ ' RK <br /> Exceltech understands that the followingwork has s been accomp]is5ed at the site (Figura <br /> Background <br /> L On November 14, 1989, one 8,000-gallon unk'mded gasoline tank, two 5,000-gallon <br /> unleaded gasoline tanks, and one 5,000-gallon super unleaded gasoline tank were <br /> ^� removed and replaced.during general site renovation. Eight soil samples were <br /> taken, two from each tank excavation, and analyzed for total petroleum <br /> hydrocarbons (TPH) and benzene, toluene, ethyl benzene, and total xylene isomers <br /> 1 (BTEX). Concentrations of TPH ranged from 1.9 to 3,600 parts per million <br /> (Ppm). <br /> 2. The excavation was backfiIIed with its original soil and soil from the new ta.k <br /> excavation. <br /> 3. In anticipation of additional plume delineation activities and the need for a vapor- <br /> extraction system, GASCO installed eight 2-foot-diameter utility holes at the <br /> l approximate locations shown on Figure 1, Each utility hole has a 2-inch-diameter <br /> steel pipe buried between the hole and an area previously selected by GA.ICO ns <br /> appropriate for a vapor and groundwater Esea.trrtent system. <br /> 4. On December 19, 1989, an electromagnetic induction survey was conducted on the <br /> site to aid in investigating the areal extent of the plume and to assist in locating <br /> groundwater monitoring wells. <br /> 3 1 <br /> . 5. On January 26, 1990, three round , <br /> Figure I), developed, and sampled in accordance twith regulatory <br /> were installed {see <br /> g atory gi;adelrnes. Sail <br /> samples collected at 5-foot intervals during the boring were tested for(he presence <br /> � of petroleum hydrocarbons as gasoline, In addition, boring BIM-1 was tested for <br /> BTEX at 15 feet. Results of laboratory analysis of the soil and groundwater <br /> samples are presented in Tables 1 and 2. Currently, all three monitoring wells are <br /> � dry because of a dropping groundwater table, <br /> Work Plan <br /> 6' Exceltech proposes to insta!1 four groundwater monitoring Lorin <br /> wells in <br /> an <br /> attempt fI em t to define <br /> the P <br /> extent of soil and <br /> � groundwater contamination at the site. It is anticipated that <br /> groundwater is at an approximate depth of 60 to 65 feet. We propose to construct the <br />