SITE INFORMATION AND CORRESPONDENCE_FILE 1

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' M LEEDSH ILL-HERKENHOFF, INC. In April 1988 a site investigation was conducted by others to determine the presence or absence of petroleum hydrocarbon soil contamination at this site. A soil boring was installed by others in the center of the previous excavation. The boring TB1 was drilled to a total depth of 40 feet with soil samples collected at depths of 2 feet, 5 feet, and at 5- foot intervals thereafter. With the aid of an on-site organic vapor detector, samples collected from 2, 10 and 15 feet were selected for laboratory analysis. These samples were analyzed for total petroleum hydrocarbon (TPH) as both gasoline and diesel. These results are summarized on Table 1 and the laboratory certificates are also enclosed. The representative soil samples tested by others showed the near surface presence of residual TPH as gasoline from a depth of 2 to 3 feet. All other soil analysis from boring TB1 showed non detectable levels of TPH as both gasoline and diesel. In an effort to remediate the site, based on this analytical data and the original tank removal permit, soils were excavated to a depth of approximately 4 feet and stock piled on site. The existing excavation and 100 cubic yard soil stockpile are the results of this remediation attempt by others. CONCLUSION AND RECOMMENDATIONS As presented on Table 1, the residual petroleum hydrocarbons in the existing soil stockpile and the barrels containing soil are almost all below minimum detection limits. These extremely low residual levels are well below concentrations which would pose a threat to groundwater resources in the area/Soil samples from the excavation below a depth of four feet also show non detectable levels of petroleum hydrocarbons. LH therefore recommends and requests San Joaquin Local Health District approval for disposal of this on site stockpile material as a non hazardous material. LH further proposes to backfill the existing on site excavation with this stockpiled material to eliminate the existing physical hazard within the fenced property. The fill will be compacted to prevent erosion and settling. Leedshill-Herkenhoff believes these proposed actions at this site are appropriate and requests written concurrence from the San Joaquin Local Health District. If you have any questions, please contact Mike Tognolini, Dick Brunner, or me at 415/243-9980. Sincerely Q�gFESSJp�,� S. Nq lF 0.J V 7Y, Gerry S. Nakano, P.E. LU Vice President cc No. 29 2" Enclosure cc: Jeane Zolezzi, Neumiller & Beardslee `�f3Fal�c Thomas Peltier, CRWQCB Don Roek, Roek Brothers Construction 9832-12.rb/293(m)