SITE INFORMATION AND CORRESPONDENCE

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I r 17, Messrs Trommer and Llr 19 June 2008 Preliminary Five-Year Review Letters. Page 4 of 7 Various Sites recommendation. A site conceptual model (SCM) has been received, upon its review the EHD will direct a feasibility study be conducted and reported. 1817 Fresno Avenue, S. • The CUF concurs with the EHD that a limited linvestigation be conducted to confirm the extent of impacted groundwater toward the east; an investigation has been conducted and a report of findings is pending. The EHD will review the report after, its submittal and will issue appropriate directives based on the findings. 4407 Waterloo Road, E. • CUF concurs with the EHD directive to implement active remediation (SVE) and recommends evaluation of in situ air sparging (IAS) as a means of achieving WQOs more rapidly. The EHD will direct assessment of groundwater remediation technologies.The SVE wells are installed and system operation is"pending. 8200 Highway 99 l CUF concurs with the EHD that the existing remediation system should continue in operatioin. A new extraction well is online that has dropped the water table enough to dry up extraction well EW-2. 2085 Fremont Street, E. • The CUF recommended that the EHD direct assessment of remedial technologies and implement active remediation to achieve WQOs in a timely manner. The EHD agrees with these recommendations and has so directed the RP. A feasibility study has been received and EHD]review is pending. 1207 Aurora Street • The CUF recommends site closure consideration, the EHD believes the site may be ready for closure consideration toward the end of the year; the ozone injection system has recently been put back online, after a non-operational period, and includes some new deeper injection wells to address a lingering presence of 1,2-DCA. 1022 Highway 99 The CUF recommends the EHD direct assessment of remedial technologies to address TPH-g, TPH-d, fuel oxygenates and implement remediation without delay. The EHD does not agree at this time; new''�data from recent borings has been acquired, which when received and reviewed may tie a significant portion of the contamination on the site to the above ground storage tank system; if so, the site will be referred to the CVRWQCB for regulatory.oversight. 620 Charter Way, W. i The CUF recommends the EHD direct the RP to monitor the recently installed monitoring wells for a full hydrologic cycle prior to assessing the need to conduct active remediation; the EHD agrees with this recommendation. j 5-Year Review Comment Letter 061908.doc I�