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DATE August 14,2003
<br /> QUARTERLY GROUNDWATER MONITORING REPORT—SECOND QUARTER 2003
<br /> 1 Facility Former E-Z Serve No 100878 Site Address 1012 West Yosemite Avenue,Manteca,California
<br /> ResponsibleP /Contact Person RPMS CA I Jeff Burke,Project Manager
<br /> Consultor Co /Contact Person ATC Associates Inc /Todd Hafner,Project Manager 209 579-2221
<br /> ATC Project No 54 25827 2512
<br /> Re ulato A enc /File No I County of San Joaquin,Environmental Health Division/ 1452
<br /> ' WORK PERFORMED THIS QUARTER [April 1,2003—June 30,2003]
<br /> 1 Performed second quarter groundwater monitoring and sampling
<br /> 2 Prepared second quarter groundwater monitoring report
<br /> ' WORK PROPOSED FOR NEXT QUARTER [July 1,2003—September 30,20031
<br /> 1 Perform third quarter groundwater monitoring and sampling
<br /> 2 Submit third quarter groundwater monitoring report
<br /> Current Phase of Project Assessment Assessment,Remediation,etc
<br /> Frequency of Sampling uarterl (Quarterly,etc
<br /> Frequency of Monitoring Quarterly (Monthly,etc
<br /> '
<br /> Liquid Phase Hydrocarbons Present On Site No Yes/No
<br /> Cumulative PSH Recovered to Date Unknown Gallons
<br /> FSH Recovered This Quarter None Gallons
<br /> Pure Water Removed This Quarter 135 Gallons
<br /> ' Permits for Discharge None DPES,POTW,etc
<br /> Current Remediation Techniques None SUES,PSH Recovery)
<br /> Approximate Depth to Groundwater 16 62 to 18 28 Measured Feet
<br /> Groundwater Gradient 0 0027 ft/ft (Magnitude)
<br /> Groundwater Flow Direction North Direction
<br /> ' Discussion On May 30, 2003, ATC Associates Inc (ATC) personnel gauged eight groundwater monitoring wells (Figures 1 and 2)
<br /> Depth to groundwater ranged between 16 62(MW-7)to 18 28(MW-3)feet below ground surface(bgs) The calculated hydraulic gradient
<br /> is approximately 0 0027 ft/ft towards the north(Figure 2) No measurable phase-separated hydrocarbons(PSH)were recorded during this
<br /> monitoring event Groundwater elevations and contours are illustrated on Figure 2 and groundwater monitoring data are presented in Table
<br /> I
<br /> On May 30, 2003, ATC collected groundwater samples from monitoring wells MW-1 through MW-8 using the sampling procedures
<br /> described in Appendix A Field logs are also included in Appendix A Groundwater samples collected were analyzed for total petroleum
<br /> hydrocarbons quantified as gasoline (TPHg)by EPA Method 8015B, benzene, toluene, ethylbenzene, and total xylenes (BTEX)by EPA
<br /> Method 8021B, as well as fuel oxygenates and additives methyl tert-butyl ether(MTBE), di-isopropyl ether(DIPE), ethyl tert-butyl ether
<br /> (ETBE),tert-amyl methyl ether(TAME),tert-butyl alcohol(TBA), 1,2-dichloroethane(1,2-DCA), 1,2-dibromoethane(EBS),ethanol,and
<br /> methanol by EPA Method 8260B TPHg concentrations above the laboratory-reported method detection limit of 50 micrograms per liter
<br /> ' (pg/L)were reported in three of the eight wells sampled in the second quarter The highest TPHg concentration was detected in the sample
<br /> collected from MW-5 at a concentration of 3,600 pg/L Benzene was detected at concentrations of 0 8 lig/L and 5 0 pg/L in the
<br /> groundwater samples collected from MW-2 and MW-5, respectively MTBE was detected at a concentration of 2 7 pg/L in the
<br /> groundwater sample collected from MW-6 D1PE, ETBE, TAME, TBA, I,2-DCA, EDB, ethanol, and methanol concentrations were
<br /> ' reported below their respective laboratory reporting limits in all of samples collected from the eight monitoring wells TPHg,benzene,and
<br /> MTBE concentrations are illustrated on Figure 2 and historic groundwater analytical results are presented in Table 1 Groundwater
<br /> analytical results'for fuel oxygenate and additives are presented in Table 2 Hydrographs of groundwater elevations and analytical data are
<br /> attached in Appendix B and laboratory analytical results and chain-of-custody documentation are attached in Appendix C
<br /> I I
<br /> Recommendations Recent historical groundwater quality data indicate impact to groundwater is minor None of the requested analytes,
<br /> were detected at or above'regulatory levels in any of the groundwater samples collected on May 30,2003,with the exception of the
<br /> ' groundwater sample collected from MW-5 Benzene was detected in this sample at a concentration of 5 0 pg/L Historical groundwater
<br /> quality data indicate trends of reduced petroleum hydrocarbon concentrations in groundwater samples collected from the monitoring kells,
<br /> which suggests natural attenuation has occurred and is continuing Petroleum hydrocarbon constituents have'not been detected in samples !1
<br /> collected from MW-3,MW-4,MW-7;and MW-8 for'at least alcouple of years ATC recommends the site be considered for closure Until
<br /> the San Joaquin County Environmental Health De artment has made a determination as to whether the site should be considered for {{'
<br /> t ,
<br /> 2"d Quarter 2003 Groundivater Report EZ SERVE #100878 ' ATC Associates`lne !
<br /> 'I S lEnviromenial125827\251MantecalReportsTZ878(2003 Q2 GW Rpt)doc ATC Protect No 54 25827'25112 I
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