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0 LFR a • 1 <br /> An area exhibiting product and staining of granular backfill soils was observed in the utility trench , <br /> for the relief line to above ground tank S-6, and hand excavation to the depth of groundwater , <br /> proceeded along this line from the vicinity of the transmix pump to the firewall (Figure 3). <br /> Although much of the soil column within the area of visibly stained surface soil shown on Figure 2 ' <br /> did not exhibit evidence of staining by fresh product from the back-pressure valve release, product <br /> floating on groundwater was encountered within the borings completed within this area. Therefore, <br /> hand excavation of soil to the depth of groundwater was performed to allow for additional floating ' <br /> product recovery. Hand excavation of soil continued, based on product observations in <br /> exploratory borings, until no evidence of product or significant soil staining was observed, or until <br /> further excavation could not be performed without compromising the integrity of operational ' <br /> equipment within the manifold area. The resulting excavation was approximately 23-feet wide by <br /> 70-feet long, and is shown on Figure 3. <br /> Excavated soil and gravel was placed in properly labeled 20-yard covered roll-off soil bins for ' <br /> subsequent characterization. <br /> Approximately 189 tons of gravel and soil excavated during the response activities were placed in , <br /> a total of sixteen 20-yard covered roll-off soil bins and temporarily stored onsite. These materials <br /> were characterized, as described below, and disposed of at Forward Landfill in Manteca, ' <br /> California by KMEP under appropriate manifests. <br /> Waste Characterization Soil Sampling Activities ' <br /> Six soil samples were collected on July 26 and August 1, 2006 from the 20-yard covered roll-off <br /> soil bins. The soil samples were collected in labeled brass sleeves, double bagged, and placed in ' <br /> an ice-chilled cooler. <br /> The soil samples were submitted to Alpha and analyzed for TPH-diesel range organics (TPH- t <br /> DRO) and TPH-gasoline range organics (TPH-GRO) using EPA Method 8015 Modified as well as <br /> benzene, toluene, ethylbenzene, and total xylenes (BTEX compounds) and the fuel oxygenates <br /> methyl tertiary-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tertiary butyl ether (ETBE), <br /> tertiary amyl methyl ether (TAME), tertiary butyl alcohol (TBA), methanol, and ethanol using <br /> EPA Method 826013, <br /> Confirmation Soil and Groundwater Sampling Activities t <br /> Confirmation sampling activities were conducted at the completion of soil excavation activities to t <br /> assess for the presence of residual petroleum hydrocarbons in soil and groundwater within the <br /> manifold area related to the back-pressure valve release. , <br /> The soil sampling activities included the collection of confirmation soil samples at 17 locations <br /> from within the footprint of the excavation (Figure 3, SS-1 through SS-17). One soil sample was ' <br /> collected from each location approximately midway between the bottom of the excavation and the <br /> t <br /> 4 ' <br />