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i <br /> ENVIRON6ENTAL HEALTH b EPARTMENT <br /> aQU k SAN JOAQUIN COUNTY <br /> UF�6'0-4 <br /> Program Coordinators <br /> Donna K. Heran, R.E.H.S. <br /> Director304 East Weber Avenue,Third Floor Carl Borgman,R.E.H.S. <br /> Laurie A. Cotulla,R.E.H.S. Stockton,California 95202-2708 Mike Huggins, R.E.H.S., R_D.I. <br /> Assistant Director Margaret Lagorio, R.E.H.S. <br /> Telephone: (209)468-3420 <br /> Robert McClellon, R.E.H.S. <br /> Fax: (209)464-0138 Jeff Carruesco, R.E.H.S. <br /> Website:www.sjgov.org/ehd/ Kasey Foley, R.E.H.S. <br /> JOHN PESTANA Q-TIP TRUST CCT 12 2006 <br /> DONALD PETERSON <br /> PO BOX 672 <br /> t <br /> MANTECA CA 95336 <br /> Re: Former Reeve's Exxon Site Code: 1397 <br /> 2360 East Street RO#: 200 <br /> Tracy, CA 95376 SWRCB-CUF#: 3484 <br /> The San Joaquin County Environmental Health Department (EHD) has received and reviewed <br /> Investigation Summary Report/Site Conceptual Model (the ISR/SCM) dated June 30, 2006 as <br /> prepared by Ground Zero Analysis, Inc. (GZAI)on your behalf, and the EHD comments as follows: <br /> The ISR/SCM covers the additional subsurface investigation directed by EHD that was conducted July <br /> 19, 2005 by advancement of five push point type soil borings, "SB-12D" and "SB-13D" and "SB-14" to <br /> "S13-16". Laboratory analytical results for soil samples collected from the five soil borings demonstrated <br /> that only SB-14, located just north of the former waste oil underground storage tank (UST) penetrated <br /> soil impacted by petroleum hydrocarbons at significant concentrations. Total petroleum hydrocarbons <br /> as hydraulic oil (TPH-ho) at 16,000 milligrams per kilogram (mg/kg) was detected at 10 feet below <br /> ground surface ('bgs) in SB-14, which also contained total oil and grease (TOG) at 20,000 mg/kg, and <br /> low concentrations of TPH as gasoline (TPH-g) and benzene, toluene, ethylbenzene and total xylenes <br /> (BTEX). The deeper soil sample in SB-14 at 15' bgs did not contain detectable concentrations of any <br /> of these constituents. <br /> From the data developed from this and previous site investigations, GZAI concluded: <br /> • Gasoline contamination extends beneath and down-gradient of the former product lines; <br /> • Gasoline contamination occurs in the vicinity of and down-gradient of the USTs formerly on the <br /> property; <br /> • Hydraulic oil impacts the subsurface in the vicinity of the former waste oil UST; and <br /> • A zone of commingled contamination occurs at the north end of the property where gasoline <br /> origination from the former on-site USTs mixes with longer-chain hydrocarbons inferred to <br /> have been released from a pipeline north of the site. <br /> Based on the findings and conclusions presented in the ISR/SCM, GZAI recommended that no <br /> additional investigation be conducted in the down-gradient direction (north) due to the commingling of <br /> the subject site plume and an inferred release from the pipeline north of the site. <br /> The EHD concurs with the interpretation that gasoline fuel has impacted soil and groundwater in the <br /> immediate areas of, and in the down:gradient direction from, the former product lines and the former <br /> USTs, and that hydraulic oil has impacted the subsurface in the vicinity of the former waster oil LIST. <br /> The EHD does not concur at this time with the interpretation of commingling of contaminants released <br />