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Ms. Margaret Lagorio,SJCEHD January 5,2005 <br /> Work Plan for Additional Site Assessment and Project No. 2033-15600-01 <br /> Evaluation of Remedial Alternatives <br /> Joe's Truck Plaza,Lathrop,California <br /> Page 8 <br /> butyl ether (ETBE), di-isopropyl ether (DIPE), TBA, 1,2-dichloroethane (1,2-DCA), <br /> 1,2-dibromoethane (EDB), methanol, and ethanol by USEPA Method SW8260B. <br /> Task 4: Evaluation of Remedial Alternatives <br /> Ozone injection will be evaluated as a remedial option for this site. A minimum of two <br /> soil and two groundwater samples for chemical analysis and possible bench-scale testing <br /> will be collected during the assessment activities proposed above. These samples will be <br /> analyzed for CAM 17 metals (including Cr6+) and general minerals, as required by the <br /> Regional Water Quality Control Board (RWQCB). A toxicologist/chemist will evaluate <br /> the analytical data to ascertain if metals or minerals of concern are present at levels <br /> favorable for adverse reactions. If the toxicologis's/chemist's report concludes that <br /> metals or minerals of concern are not present at levels favorable for adverse reactions, <br /> Stratus will propose a pilot study be performed. Results of these analyses, the <br /> toxicologist's/chemist's conclusions, and Stratus' recommendations regarding pilot <br /> testing will be submitted in a separate report <br /> Air sparging does not appear to be a viable remedial alternative applicable to the site <br /> conditions. MTBE is hydrophilic, and will not easily or efficiently be stripped from the <br /> groundwater by in situ air bubbling. In addition, Sands A and B, in which air sparge <br /> wells would be set, are not thick enough for efficient air sparge operation. The shallow <br /> depth to water beneath this site does not leave enough vadose zone to install an effective <br /> vapor extraction well network that would also be required to capture sparged air. Ozone <br /> injection appears to be a more efficient means of introducing oxygen into the <br /> groundwater (for chemical reaction and stimulation of possible biodegredation). For <br /> these reasons, Stratus is not recommending a pilot study of air sparging at this time. <br /> Previous feasibility testing at the site has established that DPE is technically viable as a <br /> groundwater extraction tool, given the site conditions. Stratus will also evaluate the <br /> efficiency of groundwater pumping as a remedial option. A temporary groundwater <br /> extraction and treatment system will be installed at the site, and will operate as an interim <br /> remedial system. This interim system will extract impacted groundwater from existing <br /> wells MWO-1X, MW-2, and MW-3. Details regarding installation of this temporary <br /> system will be included in an Interim Remedial Action Plan (IRAP). <br /> Task 5: Data Evaluation and Report Preparation <br /> After completing the soil boring and well installation activities, and receipt of all <br /> associated analytical laboratory results, Stratus will prepare a report summarizing the <br /> findings. The report will summarize work conducted to date and present the findings of <br /> the additional assessment. The report may include groundwater flow and gradient maps, <br /> K:Uoe's Truck Plaza\Work PlansUoes workplan 010505.doc <br />