SITE INFORMATION AND CORRESPONDENCE

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v %woe page 2, 7500 Eleventh St. The business located across Chrisman Ave. from the subject site, C & 8 Equipment, address 7474 W. Eleventh St., is currently an underground tank site on the PHSIEHD Contaminated Site List. Monitoring wells have been installed at this site, one of them within 75-feet of the proposed MW-5. Groundwater gradient at this site has been consistently evaluated as flowing to the north-northwest. A copy of the site map showing the location of the existing monitoring wells and copies of the most current soil and groundwater analytical data are included for your information. For beginning site investigative purposes, the information from 7474 W. Eleventh St. can be used as an indication of lateral contaminant definition to the east of the subject site. Another contaminated site, Fayette Manufacturing, is located at 7675 W. Eleventh St., which is across the street to the northwest from the subject site. Groundwater gradient at this site has also been noted as flowing to the north-northwest. PHSIEHD feels that sufficient groundwater gradient information exists to indicate that it is unlikely that contamination from the subject site has migrated across the intersection of Eleventh St. and Chrisman Road to the northeast. It is the understanding of PHSIEHD that the proposed geoprobe soil borings will be advanced to depth until the retrieved soil samples appear upon observation to be free of petroleum hydrocarbon contamination. Should this prove to be impractical due to the limitations of the geoprobe technology, the work pian states that borings to depth for vertical definition will be completed with hollow-stem augers during placement of monitoring wells. Please note that depending upon the anticipated depth of the monitoring wells, such borings may require back filling with neat cement grout prior to setting a well casing. The geoprobe work will be considered the initial phase of site investigative work. Once all the information obtained from the geoprobe borings is evaluated, which will include both soil and groundwater analytical data, the practical locations for the groundwater monitoring wells will be determined. Initial consideration is that they will be placed to surround the outer limits of the aqueous plume for lateral definition and near the center of the plume for contaminant concentration and vertical definition. It is understood from the work plan that the proposed wells will be built to encounter first groundwater, to a maximum depth of 20 feet below surface grade (bsg). The need for deeper, discretely screened wells can be determined following determination of the vertical contaminant profile and subsurface Ethology. Please note that it is the recommendation of PHSIEHD that all wells be surge-blocked following installation of the filter pack and prior to placement of the bentonite plug. The work plan states that following the completion of the site characterization, a Corrective Action Plan (CAP) will be prepared. To comply with the California Underground Storage Tank Regulations, Title 23, Division 3, Chapter 16, Article 11, Section 2725, the CAP shall include a feasibility study that evaluates at least two remediation alternatives. The alternatives will be evaluated for cost effectiveness and for their potential to remedy the documented contamination. Reference is made in the work plan to the SJCHCSA. Please have your consultant inform PHSIEHD to whom this refers. All work performed at this site shall be done under the approval and inspection of PHSIEHD. Please note that at least 48 hours notice to PHS/EHD is required prior to any scheduled field mobilization_