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messages from her we are assuming she is going t1 send a <br /> more formal letter. <br /> 10. Finally, she stated that we have always had the option <br /> to backfill the excavation at any time. <br /> In evaluating the conversation between Ms. Ratliff and myself. I <br /> feel that San Joaquin County Health does not wish us to utlize the <br /> excavation as a vapor extraction area. They would prefer to have <br /> us backfill the exca-ation, no matter what the cost increase to <br /> Wickland Oil Company this will create. They (San Joaquin County <br /> Health) want the full extent of ground water contamination <br /> outlined, prior to any other activity concerning this site and <br /> feel that we are in violation due to our not being able to obtain <br /> permission for the placement and sampling of the offsite monitor <br /> well. <br /> WORK PLAN <br /> Soil samples of the tank excavation and near by monitor wells <br /> indicate that gasoline range hydrocarbons extent to the 30 foot <br /> depth beneath the southeastern half of the excavation. Benzene <br /> levels obtained from the sampling of the excavation with a hand <br /> auger-sampler show that the highest benzene level is 12 ppm at the <br /> 20 foot level and drops to 0.64 parts per million at the 25 foot <br /> depth. All contaminants seem to be below detection limits at the <br /> ifs foot depth. Since San Joaquin County Health as hesxta,it about <br /> pre-plac..ng a vapor extraction well within the excavation and the <br /> . classification of the excavated soil shows this material to be non <br /> hazardous, we are proposing the following: <br /> To use an excavator and clean out and excavate the cavity to as <br /> deep as practical, and/or were field screening show it to be <br /> clean. Obtain soil samples of the sidewalls and base of the <br /> excavation for certified laboratory analysis. This excavating <br /> will produce approximately 100 cubic yards of soil. The excavated <br /> soil will immediately be place upon and covered with polyethylene <br /> liners. The ambient air surronding the excavation will be <br /> monitored with a portable PTD and if ambient conditions exceed 100 <br /> ppm vapor as gasoline, the excavating will cease until conditions <br /> improve, before continueing the excavating. Ti�r © f. ,, ­i� <br /> wij1V�" ea�Oi a bbd} fo'r.chomital dhalysis. jAll samples wall be <br /> preserved, labeled, and chain of cdstody hand delivered to <br /> Chemtech Laboratories for analysis using EPA methods 8015 and 8020 <br /> with 5030 extraction. <br /> Overexcavation of the product dispensing is-.and is not practL al <br /> due to the overhanging canopy. To remediate the gasoline range <br /> contaminated soil beneath the pump island, four vapor recovery <br /> wells will be hand augered with a 7" diameter auger to the 20 foot <br /> depth. A 1" diameter machine slotted (0.02" ) , schedule 40 PVC <br /> pipe will be installed into the augered hole and then backfilled <br /> with 1/4" pea gravel as a sand pack. The vapor extraction wells <br /> will be manifold with 2" PVC pipe to a common treatment area, and <br /> 3 <br />