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Hydrocarbons were detected only in samples JL-P-13�and JL-P=15' Both of these samples were collected on the west wall, where further excavation would have risked undermining the service station building A TPH concentration of 9 mg/kg (ppm) was detected in JLP-135 which was collected from the caliche-cemented clay bed (unit 5) This bed appears to have served as a "sponge" that absorbed much of the gasoline and prevented significant downward migration into underlying units This was evident, for example, during excavation of the south wall, where PID readings of >1300 ppm were recorded at a depth of 18 feet near the top of unit 5 but readings of <200 ppm were recorded near the base of this unit at a depth of 26 feet On the north wall, readings dropped from >1900 ppm at 18 feet to 265 ppm at 20 5 feet in this unit Below a depth of 26 feet, no PID readings exceeded 50 ppm anywhere in the excavation Sample JL-P-15,was collected at a depth of 12 5 feet near the top of unit 4 or base of unit 2 The high TPH concentration (4200 ppm) probably represents "ponding" of gasoline above the less-permeable clay of unit 5 Of the BTEX components, only the less volatile ethylbenzene and xylene were detected, the absence of benzene and toluene suggests that the lighter fractions have been lost due to weathering No contaminants were detected in the water sample from the domestic well 7.0 DISPOSAL OF EXCAVATED SAIL 7.1 Procedures , Prior to the start of excavation, Elite N set up an on-site dispatching office to oversee the transport of the excavated soil to REMCO's disposal facility in Richmond, California When a truck arrived for loading it was logged in, and the driver was given a manifest and bill of lading After being logged 11i, weighed, and unloaded at REMCO, the truck returned to the site and the driver delivered the scale ticket to the dispatcher and was again logged in This procedure made it possible to keep an accurate record of the transport time and tonnage of each load A total of 198 ,truck loads were transported by Bob Evans Trucking According to REMCO's measurements, 4,155 tons of soil were received This amounts to an average of 21 tons per load 7.2 Volume of Excavated Soil The volume of soil that was removed and disposed of can be calculated by two methods To calculate the volume based on the weight of soil received by REMCO, it is necessary to estimate the volume of a ton of soil In general, the weight of a cubic yard of soil vanes between 1 ton for dry sand to 1 5 tons for wet clay Based on the thickness of the various stratigraphic units (Figures 6-8), the sand clay ratio of the excavated soil was approximately 3 1 Therefore, we estimate that one cubic yard of excavated soil weighed approximately 1 1 tons The volume of transported soil can be-calculated as follows 6