Laserfiche WebLink
Fourth Quarter 2001 Monitoring and Sampling Report 2 <br /> 7-Eleven, Inc,Store#21756 853 E Yosemite Avenue,Manteca,CA December 13,2001 <br /> Monitoring Well Sampling and Analytical Results <br /> ' The groundwater samples were collected using disposable bailers Groundwater samples wereP laced in <br /> ' analysis-specific containers with analysts-specific preservative The samples were then sealed using Teflon <br /> septum caps, labeled with the job identification number,the sample number,date,time, and type of <br /> laboratory analysis required The samples were stored on ice and transported with a chain-of-custody <br /> record to a state-certified laboratory Groundwater samples were analyzed for BTEX,MTBE, and TPH-G <br /> ' using EPA methods 8021/modified 8015 and for the oxygenates MTBE, TBA, DIPE, ETBE, and TAME <br /> using EPA method 8260 <br /> ' Dissolved oxygen (DO) concentrations were measured in the three wells prior to sampling Dissolved <br /> oxygen readings ranged from 1 5 milligram per liter(mg/L)to 3 0, indicating aerobic conditions (Table 1) <br /> ' Quarterly analytical results are summarized in Table 1 and historical results are summarized in Table 2 <br /> Dissolved benzene was detected only in well MW-1 at a concentration of 7 1 microgram per liter (ug/L) <br /> ' Dissolved TPM-G levels ranged between non-detectable (wells MW-2 and MW-3) and 600 ug/L(well <br /> MW-1) Dissolved MTBE concentrations ranged between 11 ug/L (well MW-2) and 120 ug/L(well <br /> MW-1) The other oxygenates were not reported above detection limits in any of the wells sampled The <br /> laboratory analytical reports for the groundwater samples are included in Attachment 4 <br /> Sensitive Receptors <br /> ' As mentioned in previous quarterly reports, a well search database for public water supply wells located <br /> ' within one mile of the site indicates that the nearest well is an active municipal well located 1,987 feet <br /> downgradient of the site, it is 155 feet deep,with top of screen at approximately 65 feet below grade <br /> Purge Water Transportation and Disposal <br /> ' Purge water generated during this quarterly monitoring and sampling event was stored in 55-gallon <br /> Department of Transportation (DOT) -approved drums pending characterization and proper disposal by a <br /> licensed waste hauling company <br />