ARCHIVED REPORTS XR0007668 - Laserfiche WebLink

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' Firestone Service Center 400 North El Dorado, Stockton, California February 2, 1994 Soil Remediation Plan —2072.01 Page 4 of 6 completed during assessment activities, will be utilized as a monitoring point Four additional well points will be advanced The proposed monitoring point locations and screened intervals are shown on Figure 2 Soil gas analysis for TVPH by EPA Method TO-14 will be completed at each monitoring point immediately after installation Monitoring points indicating significant initial soil gas concentrations will be monitored periodically thereafter ' Those wells exhibiting non-detect or insignificant readings will not be further evaluated for volatile hydrocarbons A soil sample will be obtained for TVPH analysis during installation of monitoring point M 3 to enhance delineation to the east Once the system is started, the vacuum will be monitored at each monitoring point to verify the radius of influence In addition, soil gas concentrations and the flow rate will also be measured at the unit discharge, prior to carbon filtration The extracted vapor samples will be analyzed for TVPH by EPA Method TO-14 at system start up and periodically thereafter to establish a trend in vapor contaminant concentration Intermediate soil gas monitoring will be performed utilizing a PID The data will be utilized to determine when site closure is appropriate Initial off-gas VOC and moisture concentrations will be measured at system startup Based on these measurements, the estimated mass of VOCs and water extracted over time will be calculated This mass/time calculation will be compared to the carbon canister adsorption specifications to establish necessary off-gas ' monitoring frequency Appropriate off-gas monitoring will ensure against VOC breakthrough within the carbon adsorption treatment process ' Air discharge, after carbon filtration, will be monitored with a PID to verify sufficient treatment If PID readings indicate a possible breakthrough, the system will be turned off Vapor extraction monitoring will be performed for two days after system startup Based on the data collected, system performance will be evaluated to determine ' the frequency of future monitoring Monitoring frequency may be reduced to a weekly, brweekly, or monthly event, or as required by the air permit Initially, air inlet wells will not be utilized Although the concrete and asphalt surfacing creates a relatively impervious cover over the area to be remediated, it is anticipated that there is sufficient vapor permeability for operation of the VES During system operation, monitoring data will be evaluated to determine if air inlet wells are needed If necessary, air inlet wells will be installed Some of the monitoring points may also be utilized as passive air inlet wells, as appropriate RYAN-MURPHY. INCORPORATED Denvw EawkonmeaW Constracboa M111111 =t Los Angelm