SITE INFORMATION AND CORRESPONDENCE FILE 1

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N FILE � PUBLIC HtALTH `SERVIC7PS ,oPQ�'�N SAN JOAQUIN COUNTY a ?� ENVIRONMENTAL HEALTH DIVISION Karen Furst, M.D., M.P.H., Health Officer a 304 East Weber Avenue, Third Floor • Stockton, CA 95202 2091468-3420 SEP 15 2000 GEORGE AND MEI TERANISHI 1600 WEST DURHAM FERRY RD TRACY CA 95376 Re: George's Service Site Code: 1550 1600 West Durham Ferry Rd. Tracy, CA 95376 On June 20,2000,your consultant,Geological Technics, submitted a work plan for the above referenced site to the San Joaquin County Public Health Services Environmental Health Division(PHS/EHD) for review. PHSIEHD subsequently disapproved of the work plan because it lacked specific information and data to support conclusions presented in the plan regarding remedial alternatives proposed for the site. PHSIEHD informed you in a letter dated July 3, 2000,that further information would be necessary prior to approval of the remedial alternatives work plan. Moreover, in a letter dated May 5,2000 and submitted to you several weeks prior to the submittal of the June 20 work plan,PHSIEHD specifically outlined the information that would be needed in the work plan before approval would be provided. Additionally, PHSIEHD staff met with you and your consultant on location at the site on July 24, 2000 to discuss corrective action requirements. To further ensure that the appropriate and necessary elements were included in the new work plan the consultant was encouraged by PHSIEHD to review documentation for an Air Sparging and Soil Vapor Extraction(ASISVE)technique that is being successfully utilized at a nearby site with similar lithology. PHSIEHD provided the file for the nearby site for the consultant's review. PHSIEHD received and reviewed a revised Remedial Alternative Feasibility Study Work Plan(Work Plan) dated August 17,2000 prepared by Geological Technics for the above referenced site. The preferred remedial alternative,as stated in the work plan, is excavation of contaminated soil instead of ASISVE. However,PHSIEHD conditionally approves the Work Plan in the interest of facilitating corrective action at the site. Specific data to support contaminated soil removal in lieu of soil vapor extraction and air sparging for this site will be necessary. The following conditions must be met prior to scheduling the work: 1. Prior to employing source removal as a remedial method,calculations for groundwater velocity at the site and the time frame calculated for the contaminant plume to contact the nearest receptor must be provided to PHSIEHD. Calculations must begin at the time of the original contaminant release. If the time frame for contaminant plume travel to the nearest receptor is less than one year,the more aggressive ASISVE remedial method must be employed at this site. 2. Soil and groundwater mass balance calculations for the contaminant volume currently estimated to be in place at this site must be provided to PHSIEHD,as well as mass balance calculations for the amount of soil and water contaminants proposed to be removed by excavation and attenuation. Pre-treatment contaminant concentrations and the post-treatment contaminant concentration goals must be clearly stated. 3. Confirmation of contaminant mass balance concentrations in the contaminated soil removed from the site and the mass contaminant concentrations that will be left in place must be submitted in a post- excavation report. A report evaluating the soil excavation and saWling work must be submitted to PHSIEHD within 60 days of the excavation work- a re ort of findings for the source reduction and attenuation remedial method must be submitted within 60 dasof the fourthuarterl roundwater- monitorin event following the excavation work. A Division of San Joaquin County Health Care Services