REMOVAL_1992 - Laserfiche WebLink

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sand and the native soil beneath each sample location over an area as shown in Figure 3. The final grade anticipated after overexcavation of these two sample locations is as follows: Location Final Grade 02-N 16 ' bgs 03-E 18 ' bgs The soil excavated from each area will be stockpiled separately and the locations noted on our stockpile location map. 3 .2 SOIL SAMPLING The native soil remaining in each overexcavated area will be sampled by bringing a full bucket of the remaining soil to the surface with the excavator and driving a brass tube into the bucket load of soil. The ends of each brass tube will be covered with foil and capped, the tube will be labelled, and the sample will be stored in an ice chest at 40° F. Samples will be delivered to a state-certified laboratory for analysis of TPH-Diesel and BTEX. Representative samples of the stockpiled soil will be collected and analyzed in a similar fashion, except that the excavator will not be required for sample collection. 3 .3 WATER SAMPLING The rainwater pumped out of the open excavation will be sampled by collecting four discrete one liter samples from different locations in the storage tank, including one sample from the bottom drain valve. One representative composite sample will then be prepared by combining equal portions from each of these discrete samples. The composite sample will be stored in an ice chest at 40° F until it is received by the state-certified laboratory for analysis of TPH-Diesel and BTEX. 3 .4 SOIL REMEDIATION The stockpiled soil containing TPH-Diesel at concentrations less than 100 ppm and no detectable concentrations of BTEX will be used in backfilling the excavated area as described in Section 3.5. Soil which cannot be used as backfill material will be handled in one of two ways, based on the concentrations of TPH-Diesel and/or BTEX present as well as the volume of soil in this category. Any stockpiles of soil which can be accepted by Forward Landfill for use as cover will be transported directly to the landfill on 20-cubic yard end dump trucks. Soil which contains significant concentrations of TPH-Diesel or BTEX and cannot be landfilled directly will be treated by bioremediation prior to landfilling. The specific approach for bioremediation (on-site vs. off-site at Forward Landfill) and the process to be used will be presented to the San Joaquin County Environmental Health Department in an amendment to this work plan once this information is developed.