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ENVIRONMENTAL HEALTH DEPARTMENT <br /> 'SAN JOAQUIN COUNTY <br /> Uirii Snpen-isors <br /> Donna K.Heron,R.E.H.S. <br /> 304 East Weber Avenue,Third Floor Carl Dorgnnn,R.E.H.S. <br /> Dlreefor t+4ike Huggins,R.E.H.S.,R.D.I. <br /> +u Olson,rt.F.Hs. Stockton,California 95202-2708 <br /> �;• Douglas W.Wilson,R.E.H.S. <br /> • �q �p Pr-ograrn dlrinagei' Tele])ItOne: (209)4G$-3420 Nlargaret Logorio.R.E.H.S. <br /> t+FdR`� Laurie+l.C09011.1,R.E.N.S• Robert McClellon,R.E.H.S. <br /> Program brarrar er rax: (209)464-0138 <br /> black Darcclloti,R.E.H.S. <br /> FEB 14 2005 <br /> KEN HILLIARD KENDALL YOUNG <br /> 7-ELEVEN INC YLY LLC <br /> PO BOX 711 720 YORK STREET <br /> DALLAS TX 75221-0711 SAN FRANCISCO CA 94110 <br /> RE: 7-Eieven Store#32262 SITE CODE: 1505 <br /> 2360 Grant Line Road <br /> Tracy CA 95376 <br /> San Joaquin County Environmental Health Department(SJCIEHD)has begun review of Results <br /> of Site Assessment Remedial FeasiWity Testing and Site Conceptual Model(Report)dated <br /> September 30,2004, prepared on your behalf by Secor International Incorporated (SECOR)and <br /> has the following comments. <br /> The Report includes documentation of the continued assessment of the lateral and vertical extent <br /> of the petroleum hydrocarbon contamination in soil and groundwater, feasibility testing of two <br /> remedial alternatives• and a site conceptual_model(SCM). <br /> The site assessment discussed in the Report included the advancement of two cone <br /> penetrometer test(CPT)borings for investigation of the vertical extent of contamination, and the <br /> installation of three additional shallow monitoring wells for investigation of the lateral extent of <br /> contamination. Two discrete grab groundwater samples were collected at each CPT location. <br /> The sample collected from the onsite CPT-1 at 60 feet below surface grade(bsg)was reported to <br /> contain 69 micrograms per liter(pgll)total petroleum hydrocarbons (TPH)as gasoline,and 0.74 <br /> µg11 methyl tertiary butyl ether(MtBE). SECOR noted that the chromatogram appeared to <br /> indicate that this detection of TPHg was actually 2-ethyl-1-hexanol, a compound which is not a <br /> typical constituent of gasoline or diesel fuel. SECOR states that this compound is commonly <br /> associated with pipe dope. However,the chromatogram was not included in the report for <br /> SJCIEHD review,and research has indicated that this compound has been used as a fuel <br /> additive (Phillips 66 Superclean unleaded fuel additive), though it is most commonly used in <br /> consumer building and furnishing products, and in pesticides. Please provide to SJCIEHD a copy <br /> of the chromatogram, as well as documentatlon of which pipe dope product lists this compound <br /> as an ingredient,and an explanation of how SECOR considers it to be likely that pipe dope is the <br /> source of the detected contamination. <br /> Three shallow monitoring wells, MW-7,MW-8 and MW-9 were installed to investigate the lateral <br /> extent of the shallow groundwater plume in the cross-and down-gradient directions. These wells <br /> were developed and sampled on July 30,2004. Analytical results indicate that the lateral extent <br /> of the shallow plume has not been defined. The well located furthest down gradient, MW-8, <br /> contained 210 µgA MtBE. In addition,increasing concentrations of MtBE in well MW-2 indicate <br /> that further Investigation must be done to define the lateral extent of the plume towards the west. <br /> 17FEB <br /> `' Zfi T 1 v 2005 <br /> �Y>;r*rra■r.rerar■arxraaru <br />