ARCHIVED REPORTS_XR0006759 - Laserfiche WebLink

Home Browse Search

Fourth Quarter 2000 Monitoring and Sampling Report 2 7-Eleven Inc Store#21756 853 E Yosemite Avenue Manteca,CA December 28 2000 Monitoring Well Sampling and Analytical Results On October 17, 2000, groundwater samples were collected from the three monitoring wells Dissolved oxygen (DO) concentrations were measured in the three wells prior to sampling The groundwater samples were collected using disposable bailers Groundwater samples were placed in analysts-specific containers with analysts-specific preservative The samples were then sealed using Teflon septum caps, labeled with the fob identification number, the sample number, date, time, and type of laboratory analysis required The samples were stored on ice and transported with a chain-of-custody record to a state- certified laboratory Groundwater samples were analyzed for BTEX, MTBE, and TPH-G using EPA methods 8021/modified 8015 and for the oxygenates MTBE, TBA, DIPE, ETBE, and TAME using EPA method 8260 Dissolved oxygen readings ranged from 0 5 mg/L to 0 7 mg/L. (Table 1) Laboratory analytical results for groundwater samples collected on October 17, 2000 are summarized in Table 1 and histoncal results are summarized in Table 2 Dissolved benzene concentrations were below the reporting limit of 0 5 micrograms per liter (Ng/L) and TPH-G below 100 pg/L in wells MW-2 and MW- 3, concentrations of benzene and TPH-G were reported in MW-1 at 3 1 and 810 ug/L, respectively The • highest dissolved MTBE concentration was detected in downgradient well, MW-1 at 3,200 pg/L The other oxygenates were not reported above detection limits in any of the wells sampled during the fourth quarter 2000 The laboratory analytical reports for the groundwater samples are Included in Attachment 4 Well Search As mentioned in previous quarterly reports, a well search database for public water supply wells located within one mile of the site indicates that the nearest well is an active municipal well located 1,987 feet downgradient of the site, it is 155 feet deep, with top of screen at approximately 65 feet below grade Purge Water Transportation and Disposal Approximately 7 gallons of purge water generated during this quarterly monitoring and sampling event was stored in 55-gallon Department of Transportation (DOT)- approved drum pending characterization and proper disposal by a licensed waste hauling company