SITE INFORMATION AND CORRESPONDENCE

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Endich Estate c/o Alice Endich 26 February 2009 101 S.Wilson Way Page 2 of 2 that your plume is impacting the southern portion of the Roek Construction site. The Arco site is remediating groundwater impacted by the release from their UST system through ozone injection; the Roek Construction site will soon reinitiate SVE to remediate impacted soil and is under directive by the EHD to remediate groundwater impacted by the release from their former UST system; it is likely that the remediation efforts on the Arco and Roek Construction sites could be compromised by the uncontrolled migration of impacted groundwater from your site; therefore, the EHD must direct you to reinitiate operation of the SVE and GWE systems on your site. The EHD is aware of the financial difficulties faced by you and many other responsible parties at this time and will do what it can to ease the burden as much as possible while still properly managing your plume of impacted groundwater. For the EHD to approve suspension of the SVE and/or GWE systems, you must show that the plume of impacted groundwater is being properly managed and is not significantly impacting the other two sites. To do this, submit a site conceptual model (SCM) demonstrating plume delineation and behavior (defined, undefined, stable, declining, migrating, etc), the risk exposures, the plume response to the remediation systems, and the probable plume response to the non-operation of the remediation systems. If your plume will still impact the adjacent sites, an alternative plan for managing the plume should be put forward. What is needed is a plan to effectively manage the hazards and risks posed by your release with the resources available in the current economic environment. Until submission to, and approval by the EHD of such an SCM and alternative plume management plan, your site must be under active remediation. The EHD has reviewed the proposed monitoring/sampling schedule for your site; as your site has been undergoing active remediation and has had an unauthorized shutdown of the remediation systems, it is not a candidate for annual sampling of all monitoring wells; if anything, the current, more frequent sampling regimen has increased importance for the evaluation of the plume response to the shutdowns. However, review of the sampling results to date appears to show the following modifications may be made without significant impairment of monitoring the impacted groundwater: • Semi-annual sampling — MW-4, MW-6B, MW-6C, MW-7B, MW-7C, VW-1C, VW-2A, and VW-3A; • Annual sampling — MW-1, MW-2, MW-3, MW-5, MW-6A, MW-7A and MW-8; and • Biennial sampling — MW-6D, MW-6E, MW-7D and MW-7E. Further reduction of the sampling frequency may be possible after the remediation systems are put back into operation or the plume behavior without remediation is well understood. Your questions and comments should be directed to Nuel Henderson at (209) 468-3436, or by mail (address on the letterhead). Sincerely, Nuel C. Henderson, Jr., PG Margare aft gorio, RENS Engineering Geologist Program Coordinator C: Tim Cuellar—AGE—837 Shaw Road, Stockton, CA 95215 James Barton, PG - CVRWQCB - 11020 Sun Center Dr. #200, Rancho Cordova, CA 95670 101 S.Wilson Way/Directive Letter 0209.doc