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F <br /> Upon entry into the County's Local Oversight Program and your approval of the <br /> remediation workplan, site cleanup was initiated on September 30, 1991. <br /> As soil was removed from the area near the south end of the former' tank <br /> excavation, grab samples were screened with a photoionization detector to <br /> determine whether or not hydrocarbon contamination was indicated. At a depth of <br /> approximately 16.5 feet, a small amount of contamination was removed from the ` t <br /> excavation and stockpiled separately from the soils which did not appear ,to be <br /> contaminated. Next, the area near the southern end of the former pump island was <br /> overexcavated until field instrumentation no longer indicated the preseri'ce of <br /> hydrocarbon contamination. The final excavation extended to a depth of <br /> approximately 14.5 feet. Figure 1 - Site Plan in the enclosed consultant's <br /> report identifies the approximate locations of the remedial excavations. <br /> At your direction, soil samples were collected from the floor of each excavation, <br /> the west sidewall of the tank pit excavation, and the north side wall of the pump <br /> island excavation. TPH was indicated at 0.5 ppm in the sample collected from the <br /> bottom of the former tank excavation; however, it was not present at detectable } <br /> concentrations in any of the other samples. Traces of toluene were indicated in <br /> all of the samples at concentrations less than recommended cleanup guidelines. <br /> Table 2 in the attached consultant's report summarizes the analytical results. <br /> Remediation activities generated approximately 50 cubic yards of slightly <br /> contaminated soil. All soil was stockpiled on plastic sheeting on a slightly <br /> elevated portion of the property and covered with additional sheeting to prevent <br /> runoff. Two composite samples collected from the stockpile indicated the <br /> presence of 0.77 ppm and 33 ppm TPH. At this time, the soil is being profiled <br /> for acceptance into Forward Landfill. I will contact you when a removal date has <br /> been scheduled. <br /> b <br /> With your approval, all soil which did not appear to be contaminated was used to <br /> backfill the excavations. Imported backfill was used to replace the volume of <br /> contaminated soil removed during remedial activities. <br /> With the exception of disposal of the soil stockpile, it is my understanding that <br /> no additional cleanup efforts will be required at this site. If this information <br /> satisfies your concerns regarding the subject property, please indicate your <br /> concurrence with our findings in your written reply. If you have any further <br /> questions regarding these matters, please feel free to phone me at (206):` 286- <br /> 4495. If I am not available, Fred Proby may be able to answer any questions that <br /> you may have. �kk <br /> • 1 <br /> Sincerely,,, <br /> Anastasia E. Duarte <br /> Environmental Toxicologist }} <br /> 1 <br /> Enclosure <br /> a <br /> cc: Ms. Beth Thayer <br /> California Regional Water Quality Control Board <br /> aed/dec91/4026A t6 <br />