Laserfiche WebLink
J <br /> - 2 _ 21 June 2001 <br /> Former Town and County Chevron <br /> 13336 Highway 88 East,Lockeford <br /> maximum depth of 120 feet on the subject property and converted to monitoring wells. TPHg,benzene, and <br /> toluene were identified in soils down to 36 feet, and low concentrations of toluene were identified in soils down <br /> to 99 feet,the total depth of soil sampling. <br /> The three monitoring wells were purged and sampled on 10 March 2001. The only contaminant identified in <br /> groundwater was toluene in MW-2 at 5 4g/1. MtBE and other oxygenates were non-detect at appropriate <br /> detection limits. The depth to water was measured at 81 feet below ground surface. <br /> GeoSoly recommends continued sampling of the three monitoring wells to determine contaminant trends. Board <br /> and County staff discussed the results and recommendations of the Investigation Report, and agree with your <br /> recommendations. Therefore,please complete the next quarterly monitoring and sampling event by <br /> 30 June 2001, and submit the second quarter monitoring report by 15 August 2001. All groundwater samples <br /> must be analyzed for TPHg by EPA Method 8015M, for BTEX by EPA Method 8020 or 8260B, and for MtBE, <br /> TBA,DIPE,ETBE,TAME, 1,2=dichloroethane, and ethylene dibromide by EPA Method 8260B. Some <br /> laboratories can run a complete suite of petroleum constituents and fuel additives by EPA Method 8260B, <br /> thereby saving considerable cost. <br /> Until investigation and cleanup activities are complete and the site receives a No Further Action Required letter, <br /> Chevron must submit quarterly status reports to the County and Regional Board. These reports must include <br /> results of groundwater monitoring, and be prepared as presented in enclosed Appendix A to the Tri-Regional <br /> Recommendations. <br /> Also, a revised mass balance estimate must be submitted in the second quarter status report. We reviewed the <br /> mass balance estimate submitted with the Soil Boring Report, and determined that you incorrectly converted <br /> milligrams to kilograms. The result of this error has overestimated the contaminant mass in soil by 1,000 times. <br /> The relevance of estimating the contaminant mass in soil is to determine the potential for soil contamination to <br /> impact groundwater. In this case,your estimate of 67,812 kilograms of TPHg(or 22,950 gallons) shows a very <br /> high potential for soil contamination to impact groundwater. <br /> Once the County.and Board staffs review future quarterly status reports,we can determine.if additional corrective - <br /> actions are needed. Please contact Jeffrey Wong at San Joaquin County Environmental Health Division at least <br /> two business days prior to any site work or sampling. If you have any questions,please call Jeffrey Wong at <br /> (209)468-0335, or me at(916) 255-3115. <br /> Marry rtzell <br /> Associate Engineering Geologist <br /> Attachment <br /> cc: Mr.Mark Owens,UST Cleanup Fund, State Water Resources Control Board, Sacramento <br /> Mr. Jeffrey Wong, San Joaquin County Environmental Health Division, Stockton <br /> Mr.Frank Goldman, GeoSoly LLC, Sonoma <br />