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December 9 t998 ERI 227903 w02 dormer Unocal Servtce station 5098,Stockton California surface to total depth Samples anticipated to analyzed by the laboratory in the sample closest to to first the vadose zone/saturated zone interface and the historical osed borings) Additional samplese for (anticipated to approximately 64 feet in most of the p P or hotoionization detector (FID) potential analytical analysis may be selected based on visual staining pfrom eadAnalyses for oxygenated compounds will be performed on select near theeformeresource of readings.s g the two borings proposed on the Former Unocal Service property h drocarbons (see item 3 below) Consecutive soil samples collected at 5-Undergroundinter-vats Fuel Tank n- Y hydrocarbons and oxygenated compounds at Leaking detect for petroleum by LUFT} manual guideline detection limits will be used for supporting vertical delineation cone unions Dunt also requested the groundwater samples collectedprotection Agency (EPA) Method 8260 om the groundwater monitoring ells The County for oxygenated compounds utilizing U S Environmental Pro gr sampling event of Unocal recently performed these analyses as part of the quarterly g of wells at this site The results are provided in Attach ox t Because compounds, and given the existing samples collected near former potential sources did not eto Unocal', use °f oxygenated compounds fact that the tanks were removed n July 1985 (i e ° P in California), no further analyses of groundwater for oxygenated compounds will be performed This a roach was confirmed in a personal communication with Mr Mike Infurna of the County on PP December 7, 1998 Item 3 - Additional Soil Borings n In response to the request for " additional soil 1n�orm.ertion north of Unocal property This 1Thas PrpNp rty2is currently P additional soil borings have been proposed ee the dline owned by Stone Brothers and an access agreement heldrilling program and an updatede required to perform onsite Plate2 is activities Borings B1 and B2 have been added to ed in Attachment E The borings will be drilled using Gana$analysis 11 hollow performed ats5-foot included _ sampling of the borings for lithologte and potential laboratory pat ly Boris intervals from the surface to the total depth of the boring ( tIcl to e evident at 60efeet andewill Borings may be drilled below 64 feet if he presence ohydrocarbonsof cate the presence continue until at least two consecutive samples do vt°sual sitalntng, or PID read ngsoin excess of 50 hydrocarbons using field observations (1 e , o oxygenated compounds using s per mil by volume) or antil an aquitard is encountered,hwhichever yg the shallowest dept part p Laboratory analyses of selected soil samples will lnclu e EPA Method 8260 After each boring has been drilled and sampled, the boring will be backfilled with a cement bentonite grout Item 4 - Location of Fells MW20S and MW20D � ��ur}n5fl✓i►Cr�aCl'iii"ieili As stated i;, the -o.intyIs co ,crit lettcr, he City of Stockton Public December 3, in Department (the City) has indicated that M`N20 Jason Ender oand nf the cannotbeQnnstalled in their permitting P proposed location In a personal communication with Mr lane, On 98 ERI was informed that a location near the sideweasle area, onsIn tare too close too her existing 19ting wells Robinhaod Drive would be app Th roved by the City on the Montgomery Ward site to provide pertinent data to enable evaluation of dissolvedERI will ards Therefore, hydrocarbons between the former Unocal discreet Montgomery es from select depths utilizing a Y utilize direct push technology and collect discre groundwater robe (or similar) technology in the original to of MW245 and MW24D now designate geo P