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Chevron U S A , Inc January 7, 1992 <br /> 02320 1978 Page <br /> ' sample analyses are summarized by Dames & Moore in a Preliminary Report, dated August 31, <br /> 1989 (Appendix B) <br /> II <br /> Because the groundwater did not contain dissolved hydrocarbons, and the sod was <br /> ' generally impacted only above the depths of approximately 21 feet, Dames & Moore prepared a <br /> workplan for the remediation of soil The plan was approved by SJCPHS <br /> 1 3 3 SOIL REMEDIATION,JANUARY - MARCH 1990 <br /> In a workplan dated September 15, 1989, Dames & Moore proposed excavating the upper <br /> ' 20 feet of contaminated sod in discrete areas of the three previously existing dispenser islands <br /> The excavated petroleum contaminated soil was to be spread in lifts and aerated The aerated sod <br /> ' was to be composite sampled and chemically analyzed for the presence of hydrocarbons <br /> CRWQCB-CVR suggested that the treated soil be used to backfill the excavations <br /> ' Soil remediation by excavation began on January 22, 1990, and continued through March <br /> 19, 1990 The excavation was deepened to 30 feet BGS, and broadened in the vicinity of <br /> dispenser island 3 (DI-3) after field screening indicated a larger than anticipated extent of <br /> hydrocarbon-impacted soil The excavation was extended in all directions to the limits of <br /> ' hydrocarbons detected by field screening and confirmed by laboratory analyses The excavation <br /> activities ceased March 19, 1991, and aeration of soils commenced on March 20, 1991 The <br /> details of excavation activities and results of chemical analyses of sods are presented in a copy of <br /> Dames & Moore's Soil Remediation report, dated August 7, 1990 (Appendix C) <br /> ' The excavated sod was separated into "clean" and "darty" stockpiles using field screening <br /> ' techniques The clean soil was backfilled during the excavation period The stockpiled dirty soil <br /> was spread over plastic and aerated until no hydrocarbons were indicated by a photoionization <br /> ' detector (PID) The stockpiled, treated soil was sampled, the samples were composited and <br /> chemically analyzed <br /> ' During the first several months of aeration, sods were spread in approximately 12-inch-thick <br /> lifts over plastic and left in place until no hydrocarbons were detected with a PID To accelerate <br /> and improve the efficiency of sod treatment, the procedure was modified to include five days of <br /> tilling of each lift of hydrocarbon-impacted sod <br /> DDI"' GROUNDWATER <br /> HWY99FR RPT OL01 TECHNOLOGY INC <br />