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Project No. S80s0406-Q2 September 30, '1994 Page 2 the site by Texaco in 1919. Although excavated soil was reportedly aerated for several months after the tanks were removed, no soil sampling or analytical test results were reported. /Petroleum hydrocarbon soil.impacts at the site were initially reported by Uriah Incorporated in. �fi April 1991,at depths between 15 and 20 feet below the existing ground surface )in boring SB-3 located near the reported location of the former Texaco USTs. Uriah subsequently performed eight Additional borings (SB-4 through SB-11) and converted three of the borings into groundwater monitoring wells(MW-1,MW-2 and MW-3)at the locations depicted on Figure 2. Uriah reported. the presence of residual total petroleum hydrocarbons as gasoline(TPHg)and diesel(TPHd)in soil.. between the depths of approximately 15 and 35 feet bgs and:detected the,presence ofTPH&methyl. tert-butly ether(MTBE, a gasoline additive) and halogenated volatile organic compounds in the groundwater at:a depth of approximately 55 feet bgs. Uriah:and EP1l+I Techtnologies installed one vapor extraction well in the vicinity:of Emoting FB-11 which had the highest detected, TPHg sand TPHd concentrations of:11,000 and %400-m . respexvely: Boring EB-11 and the vapor extraction well are located near the reported Dation af` the former. Tesco U.M.as clepieted ort Figure 2. A vapor extraction system was ted at the a site between Jutta 1093 and March 1994 and reportedly removed approximately 3,333 dsof gasoline. Ceocon maksured the relative groundwaterelevations in the onsite Mofi toflr g wells MW.I,11i W-2 mY generally encountered between the depths 60 nd 1M'W 3 on J 1d 27,.1994. Groundwater was ener 55-and 57 feet bgs with a calculated hydraulic gradient of 0.002 +d pggd I tl ,s_,_ontltwesf The m g wed were sampled on July 1, 1.994. TPHg as gasoline was detected;at a concentration of 64 ug/L,in mw. 'MTBE and PCE were rreported,in each well at concentrations between 2.1 and 150 ug/I,- and 1.9 and 12 ug/4 respectively. Geocon excavated five t ant nu us c r exploratory borings(GEI.I through QB 5)within the pari lag lot area of the Aeon' . 13 a AIM..1994. Soil samples obtained from borfi*GB-I,. CB-3 and: GB-5 indicated the presence o at maaci�mum reported concentrations between 1,60 and 3,100. mg/i4between depths of approximat feet ka, TPHd concen�s were rerted between 3.4 and X50 mg/Kg in boringa GB-1 and GB-3 at depths between 1S and 32.5 feet... _ � bgs. Noitdeteetod vancentirations of the target compounds were reported for soil samples obtained from borings OB-2.and OB4. A summary of the historical soil a: d groundwater analytical results are presented on the attached Tables 1,II:and IV A summary of the historical reported groundwater elevation data is presented on the attached;Table III, The TPHg soil impacts appear to be bounded on the northwest,west and southern site boundaries by borings GB4, 1113-7, EB4 and:EB-6 as depicted on Figure 2.. The: vertical distribution ofthesoil.impacts encountered generally extend between depths of�W 45 feet PULSE The purpose of the:scope of services presented herein is to further delineate the latetutand v extent of residual TPH.ia sorl and,groundwater at the site and within the:adjacent public streets to