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DAMES & MOORE A PROFESSIONAL LIMITED PARTNERSHIP <br /> Pacific Gas&Eled Wc Co. <br /> Page 3 <br /> PURPOSE AND SCOPE OF WORK <br /> The purpose of our work was.to evaluate subsurface hydrocarbons is subsoil at the subject property. <br /> This was proposed to have been accomplished in two ways Initially,it was proposed to obtain soil samples from the <br /> 4 bottom of the over-excavated tank pit for chemical analyses.In-the,event sampled soils analyses report persistent <br /> levels of detectable petroleum hydrocarbons above regulatory action levels,a more-detailedinvestigation of <br /> subsurface hydrocarbons by commencing a pro-active Problem Assessment Report study wouldbe conducted. <br /> The initial phase of our site work,was limited to obtained soil samples,chemical analyses of soil samples obtained, <br /> and preparation of this written report. <br /> 1 <br /> TECHNICAL APPROACH <br /> Based upon review of previous soil sampling and_`chemical analyses at the subject property.and published data <br /> # regarding local geologic and hydrologic conditions;Dames&Moore proposed additional soil be excavated from the <br /> previous tank removal pit.Soil samples obtained from the limits.of the excavation were chemically analyzed to <br /> detectthepresence and concentrations of petroleum hydrocarbons as referenced`to:gasoline,and for the presence of <br /> lead.Our,preliminary data regarding depth to groundwater.in the vicinity of the subject property suggests <br /> groundwater currently occurs at an approximate depth of 60 feet below the surface grade. Since the results of <br /> chemical analyses from samples obtained in native soils beneath.the tank's were reported at significantly lower <br /> concentrations than the stockpiled overburden soils sampled,we surmised the concentrations of hydrocarbons reported <br /> suggest overfill spillage,rather than a tank-leak situation. <br /> FIELD OBSERVATION AND SAMPLING <br /> On November 4,1991,a Dames':&:Moore geologist visited the subject property to observe the excavation in the tank <br /> removal it and obtain soil`sam les at the depths,locations and frequency speed by the San Joaquin County <br /> i <br /> pit, P _ P <br /> Environmental Health Department(SJCEHD)representative present at the site.Mr.Harlan.Knoll of the SJCEHD directed <br /> PG&E Stockton Service Center <br /> 1 00160-290-042 <br />