ARCHIVED REPORTS XR0008207 - Laserfiche WebLink

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B Soil samples were obtained from the borings by hand augersng a 614 diameter hole then obtaining the sample by hand driving a 2"x6" sterile brass sleeve that has been inserted into a barrel sampler attached to rod extensions and a slam bar. The auger and sampler were cleaned with trisodium phosphate and clean water rinse, prior to and between sampling/augering. Upon obtaining the soil sample the sleeve is withdrawn from the sample barrel and the uncovered ends are screened with the HNU-PID, then sealed with aluminum foil, plastic end caps, then sealed with dunk tape, labeled, put into a zip lock freezer bag, and placed upon dry ice in a cooler for preservation. The chain of custody was filled out prior to leaving the site and the samples were hand delivered to ChemTech Laboratories (state of California Cert. # 359) . SOIL REMEDIATION Further demolition of the station would not be cost effective and will not take place. In order to remediate the site of the gasoline range hydrocarbons found in the soil beneath the pump island and tank excavation, limited overexcavation and the placement of a vapor extraction system is proposed. OVEREXCAVATION soil samples of the tank excavation and nearby monitor wells indicate that gasoline range hydrocarbons extent to the 30ltfoo net ath the depth besoutheastern half of the excavation. proposed bene excavator and overexcavate this area to the 30 use an foot depth or as deep as practical. Then to use the water drilling rig and auger a 36" diameter hole to ground water and nd install a vapor recovery well, see FIGURES 7A, 7B, and 7C. The sidewalls and the base of the overexcavaton and Versadrilled hole will be sampled for chemical analysis. The overaxcavation and augering will produce approximately 150 cubic yards of contaminated soil. This soil will be sampled for chemical analysis. All samples will be preserved, labeled, and ch-al- of custody hand delivered to Cheattech Laboratories for analysis using EPA methods 8015 and 8020 with 5030 extraction. The excavated soil will be covered with polyethylene liners. Previous classification of excavated soil for this site shows that this soil can be handled as non hazardous waste. overexcavation of the product dispensing island is not practical due to the overhanging canopy. To remediate the gasoline range contaminated soil beneath the pump island, four vapor recovery wells will be hand augered with a 7" diameter auger to the 20 foot 7A. A 1" diameter machine slotted (0.02" ) , depth, see FIGURE schedule 40 PVC pipe will be installed into the augered hole and then backfilled with 1/4" pea gravel as a sand pack. The vapor extraction wells will be manifold with 2" PVC pipe to a common treatment area, and secured with water tight traffic boxes, see FIGURES 7B AND 7C. The vapor extraction well within the tank excavation will constructed with 4" diameter schedule Oil PVC and can be utlized for ground water remediation if found necessary, 3