SITE INFORMATION AND CORRESPONDENCE

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• y Gealogicalrecknicsliu. Page J.M.Equipment Project 507.2 October 20,2003 In April 1999, responsibility for the adjacent independent trucking facility monitoring wells MW-1, MW-2, MW 3, MW-8 and MW-9 were transferred to J. M. Equipment. GTI also completed site inve tigation work which included the installation of three additional monitoring wells, two hand borings to 15 feet below grade surface (bgs); three soil borings advanced to 30 feetbgs, and one deep boring to 70 feet bgs. The three new wells, MW-4 through MW-6, and ive existing wells have been monitored quarterly since January 2000. In an effort to define the lateral extent of petroleum hydrocarbons, three soil borings; MW-7, MW-10 and SB-6 re advanced in May 2001. The borings were located approximately 200 feet southwest, 50 feet northwest and 100 feet west of, respectively, the former UST location. To define t ie vertical extent of petroleum hydrocarbons, one soil boring, MW-109 was also advanced to 80 feet bgs in the location of the former UST. Borings MW-7,MW-10 and MW-109 were converted into monitoring wells. The data indicates that a significant gasoline plume is pre 3ent in groundwater at the site. GTI submitted our S ptember 20, 2002 "In-Situ Remediation" Feasibility Study to the San Joaquin County Pub ic Health Department/Environmental Health Division (SJC PHS/EHD) for approval. GTI pr posed the preparation of a work plan for a small scale in-situ oxidation pilot test. The pilo test would include injecting hydrogen peroxide and ozone into the subsurface utilizing dvo to three small diameter injection wells located within five to ten feet of an existing mon toring well. The peroxide and ozone would combine to form the hydroxyl radical, wh ch would then break down the BETX and TPH in the groundwater and capillary zone at the ite. On September 30, 2(02, SIC PHS/EHD staff called GTI regarding the feasibility study plan. They requested that ve provide case history data to show that in-situ injection of hydrogen peroxide has worke on other similar sites. Our January 15, 2003 "Addendum — In-Situ Remediation Feasibi ity Study" included the requested information and the SJC PHS/EHD approved the study and directed that a detailed work plan be submitted in their March 20, 2003 letter correspcndence. GTI submitted our June 10, 2003 "Pilot Test for In-Situ Remediation" work vlan to the SIC PHS/EHD for approval. The SJC PHS/EHD approved the work plan in the", September 10, 2003 letter correspondence. Proposed Direction f Project GTI proposes per rming an in-situ oxidation pilot test to remediate the residual contaminants at the site. The results of the pilot test will be used to design a full scale treatment system (if i iecessary). The remedial work it Lcludes the following: 1. Drilling and inlalling three monitoring V diameter monitoring wells adjacent to existing monitor'ig well MW-9 (proposed peroxide injection well). 2. Perform 8 cycles of in situ remediation by injection of hydrogen peroxide as described in the work plan. 3. Bimonthly moni ring of new monitoring wells to determine system effectiveness. 4. A remedial effectiveness evaluation report will be prepared with recommendations for full scale remediation of the site. 5. Four quarterly gmundwater monitoring events will be performed during the year. 6. Four quarterly m nitoring reports will be completed for each monitoring event.