ARCHIVED REPORTS_XR0004860 - Laserfiche WebLink

Home Browse Search

,j Q . Quik Stop Market No 121 CCI Project No 12118-2 Page 2 was noted in well RW-1 Each well was purged of stagnant water prior to the collection of a sample It should be noted that the water table was at approximately the same level as that reported during the January 2002 sample round Many of the thirteen wells were found to have 5 to7 feet of water Monitoring well MW-8 was found to have approximately 4 feet of measurable water this quarter Normal field measurements, including pH, conductivity, and water temperature, were periodically recorded during the purging process A sample was collected when these parameters stabilized to within 10% of each other After the groundwater was purged from each well, the groundwater samples were (a) collected with a clean disposable bailer, (b) transferred to appropriate laboratory-supplied bottles, ( c) labeled, (d) logged on a chain-of- custody form, and (e) placed in a chilled ice chest for transportation to a state-certified laboratory Monitoring well purge data are summarized in data Table 1 Laboratory Analysis The groundwater samples were submitted to STL San Francisco (STL), a state-certified laboratory located in Pleasanton, California, for chemical analysis The laboratory employed • methods approved by the California Regional Water Quality Control Board (CRWQCB) and the EPA The groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg) and benzene, toluene, ethylbenzene and total xylenes (BTEX), using 8015M and 8021B Test Methods and fuel oxygenates including methyl tertiary butyl ether(MTBE), using EPA Prep Method 5030B and EPA Test Method 8260B Summary of Laboratory Results Five of the ten shallow groundwater monitoring wells (A-aquifer) were sampled and found to be impacted with petroleum hydrocarbons or MTBE Monitoring well MW-1, located on the northwest side of the site (Figure 2), near the intersection of Union Road and West Louise Avenue, and monitoring well MW-2, also located on the north side of the site, were both reported to be free of detectable TPHg/BTEX and MTBE compounds Monitoring well MW-3, located on the southeast side of the property, was reported to contain detectable TPHg, at 46,000 micrograms per liter(ug/L), no detectable BTEX compounds, and MTBE at a concentration of 49,000 ug/L Recovery well RW-l, located near the east side of the fuel tanks, was also reported to have detectable TPHg, at 130,000 ug/L and no detectable BTEX compounds RW-1 was also reported to have 180,000 uglL MTBE Monitoring well MW-4, screened from 33 to 43 feet in the A-aquifer, was reported to be free of detectable TPHg and BTEX compounds and reported to contain 15 ug/L MTBE Monitoring well MW-5, located on the southwest side of the site, was reported was also reported to be free of detectable TPHg and BTEX compounds but contained 30 ug/L MTBE Monitoring wells MW-I, MW-7, MW-8 MW-11 and MW-12 were all reported to be free of detectable petroleum hydrocarbons this quarter