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SOW <br /> 3 SOIL ASSESSMENT <br /> To assess the presence of petroleum hydrocarbons in the soil and potential lateral and <br /> vertical migration, soil samples were collected from three borings drilled around each of <br /> the waste oii tank excavations. The!--cations of the excavations and soil borings are shown <br /> on PIate 2, Site Plan. <br /> A pipe was exposed in the 1000-gallon tank excavation upon completion of the tank <br /> n removal. It was thought that the pipe was a discharge line from the tire shop, and the <br /> county requested additional sampling of this line. Prior to drilling the soil borings,the pipe <br /> was uncovered and shown to be a vent pipe running up the side of tho building. <br /> The San Joaquin County Department of Government <br /> Bu-!dings does not know the location <br /> or path of the former discharge fine which may be entirely under the building. The <br /> discharge pipe was not apparent in the excavation. If there was a discharge line, it may . <br /> have been removed during the original tank removal. <br /> Additional assessment of the soil in the vicinity of a discharge line can riot be conducted <br /> C,v because the existence and location of such a line is not known. <br /> 3.1 DRILLING AND SAMPLING PROCEDURES <br /> On November 1 through 3, 1989, soil borings B-1 through B-6 were drilled at the site. <br /> Borings B-1 through B-3 were drilled 2 to 10 feet radially away from the edge of the 1000 <br /> i° gallon w,Ste oil tank excavation(Plate 3). Borings B-4 through B-6 were drilled in the area <br /> of the 500-gallon waste oil tank excavation (Plate 4). Boring B-4 was drilled through the <br /> center of the backfilled excavation, while B-5 and B-6 were drilled approximately 3 feet <br /> west and 3 feet east of the excavation,respectively. <br /> als frnm.the ground surface to the termination <br /> Soil samples were collected at 5-foot intery <br /> each boring, except for boring B-1, which was continuous core drilled and logged <br /> depth of <br /> to ground water, The borings at the 1000-gallon tank excavation were advanced to depths <br /> -- -- - - ---ranging-from-41 5--to-59-feet,-and-the--borings--at--tile-500-gallon-.tank-excavationwere-.---,_—_____--- _ _ ---------__---- <br /> `` advanced to a depth of 21.5 feet. <br /> 241-89-2196 3 <br />