Laserfiche WebLink
Wm. J. Hunter & Associates <br /> "i <br /> CONCLUSIONS: <br /> 1. The vertical limits of soil & groundwater contamination have been well delineated. <br /> 2. Minor soil contamination exists beneath the southeast corner of the office& shop <br /> building, and possibly to the north along the driveway on the east side of the building. <br /> 3. The highest levels of groundwater contaminants have been measured in MW-1, which is <br /> located closest to, and downgradient from, the removed UST's. There has been a steady <br /> decrease in the levels of all contaminants since April, 1998. <br /> 4. The water table has fluctuated from an average depth of 6.39' bgl to 9.12'bgl, and has <br /> always been below the tops of the well screens, which are at 5' below grade. The <br /> hydraulic gradient has been consistently to the north/northwest <br /> 5. MTBE has not been detected in any well since the February, 1999 sampling event. <br /> RECOMMENDATIONS: <br /> Based upon the evidence obtained to date, additional investigative work is not justified, and <br /> Swe again recommend the installation of ORC material in MW-1 to reduce contamination to <br /> minimum levels. Air-sparging/soil vapor extraction is not feaible because of the shallow <br /> water table, and additional soil cannot be excavated due to the proximity of the building, an <br /> electrical transformer, and a large California Water Service water line which traverses the site <br /> in the middle of the driveway on the east side of the building.. We do not believe that <br /> additional monitoring is justified without a plan to Mitigate the remaining contamination. <br /> Until we receive instructions from your staff, we will put the wells on a semi-annual sampling <br /> schedule. We have requested a response to our proposal in the two previous reports, but <br /> have yet to receive a reply. The owners are anxious to proceed with whatever additional <br /> work is required by the County EHD in order to obtain site closure. <br /> We ask that you and your staff review the work done to date at this site, and provide <br /> guidance on hat work is required in order to obtain site closure. <br /> si D GE010 <br /> ba�Uey <br /> Hunter&Associates <br /> ",h J.. <br /> Wholesale Drug Co. ��r,.n u.ur! <br /> Mark List, RWQCB <br /> aFCM\-�< <br /> 2 <br />