ARCHIVED REPORTS XR0003386 - Laserfiche WebLink

Home Browse Search

Second Quarter 2001 Monitoring and Sampling Report 2 7-Eleven,tnc,Store#14117,2725 Country Club Boulevard,Stockton,CA July g,2001 1 Monitoring Well Sampling and Analytical Results ' Before sampling, at least four well-casing volumes of water was removed from each well The groundwater samples were collected using disposable bailers Groundwater samples were placed in 40- milliliter glass vials,which were acidified with hydrochloric acid to preserve the samples The samples were then sealed using Teflon septum caps, labeled with the fob identification number,the sample number, date, time, and type of laboratory analysts required The samples were stored on ice and transported with a ' chain-of-custody record to a state-certified laboratory for analysis The groundwater samples were analyzed for BTEX, MTBE and TPH-G using Environmental Protection Agency(EPA) methods 8021 B/modified 8015, and for oxygenates MTBE,TBA, DIPE, ETRE, and TAME using EPA method 8260B ' The analytical results for groundwater samples are summarized in Table 1 Dissolved benzene, TPH-G, and MTBE concentrations ranged up to 370 micrograms per liter(pg/L),6,200 pg/L and 10,000 pg/L, respectively Highest MTBE levels were reported in well MW-2 located In the underground storage tank pit ' (UST) area,whereas highest benzene concentrations were detected in well MW-3 located downgradient from the pump island The laboratory analytical reports for the groundwater samples are included in Attachment 4 Dissolved oxygen data taken from the monitoring wells indicate generally anaerobic conditions,with dissolved oxygen levels at or near 1 milligrams per liter(mg/L) (Table 1) There are no known public water supply wells located within one mile downgradient or crossgradient from the site ' Purge Water Transportation and Disposal ' All purge water generated during this quarterly monitoring and sampling event was stored in 55-gallon Department of Transportation (DOT)-approved drums pending characterization and proper disposal Waste disposal documentation will be forwarded once received i ' 14117Qt2 RPT