SITE INFORMATION AND CORRESPONDENCE

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r page 2, 1207 Aurora Street JJW considered five remediation alternatives, three active and two passive, for treatment of the contaminated groundwater at this site. The active methods include air sparging, groundwater extraction and ozone injection. After review of the projected costs of each alternative, JJW has recommended the use of an ozone injection system. In correspondence dated August 6, 2002 SJCIEHD requested that geological cross- sections of the site be prepared and included in the current work plan. In order for SJCIEHD to fully evaluate JJW's proposal, a site conceptual model (SCM) must be presented that justifies the proposed work, both in text and visually through updated geologic cross-sections and maps. The vertical and lateral extent of both impacted media should be demonstrated. An addendum to the work plan must be submitted that includes the following items. 1. Cross-sectional diagrams to comprehensively depict the site subsurface Iithology, contaminant distribution and potential preferential migration pathways. 2. Work plan for the installation of the ozone injection wells. -`3:- Estimated hydrocarbon mass sorbed to soil in the vadose zone and in-the-•-- saturated zone. 4. Estimated dissolved hydrocarbon mass. 5. Estimated hydrocarbon mass(es) that will effectively be addressed by the proposed remedial alternatives. An evaluation of the soil contamination must be completed and included in the addendum, along with JJW's recommendation for mitigating it. Upon receipt of the site conceptual model, SJCIEHD will complete the evaluation of the proposed scope of work. Please submit the SCM by December 9, 2002. In the quarterly groundwater monitoring reports JJW has recommended that monitoring well MW-3 be properly destroyed. This well, which is located on the north side of Jackson Ave., cross to up gradient of the groundwater flow direction, was damaged during construction activities. JJW has determined that the well has been damaged beyond repair. At this time, SJCIEHD will not require that the well be replaced, but notes that changes in site conditions may require a replacement well at a later date. A work plan for the proper destruction of the well will be required. Submit the work plan to SJCIEHD by December 9, 2002. If you have any questions or comments please call Lori Duncan at (209) 468-0337. Donna Heran, REHS, Director Environmental Health Department Lori Duncan, Senior REHS Nuel C. Henderson, Jr., R. G. LOP/Site Mitigation Unit IV LOP/Site Mitigation Unit IV cc: -Marty Hartzell, CVRWQCB Mark Jerpbak, JJW