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�t <br /> t <br /> Case Closure Summary Page 2 <br /> Leaking Underground Fuel Storage Tank Program <br /> III Release and Site Characterization Information(continued) <br /> Maximum Documented Contaminant Concentrations - -Before and After Cleanup <br /> Contaminant Soil (ppm) Water (ppm) Contaminant Soil (ppm) Water (ppm) <br /> Before After Before After Before After Before After <br /> TPH(Gas) 140 140 2.7 <0,050 Xylene 0.04 0.04 0,034 X0.0005 <br /> ITPH (Diesel) NA 3000 0.081 0.051 Ethylbenzene 0.02 0.02 0.0218 X0.0005 <br /> Benzene 0.01 0.01 0.0045 X0.0005 Oil &Grease NA NA NA NA <br /> Toluene ° 0.04 0.04 0.0021 <0.0005 Heavy Metals NA NA NA NA <br /> MTB 11.7 1.7 77.0 .0061 <br /> Comment!:Jhe before soil concentrations are from boring SB10-2 at 11 feet on 817/89, except MTBE which is from CPT1 <br /> at 20 feet in 12101. The after soil concentrations are the same as the before since the areas did not'have soil remediation, <br /> except the'TPH-diesel result which is from D2 collected 3 feet below a dispenser in 3104. The laboratory noted the diesel <br /> result does not meet the laboratory standard for diesel. Previous TPH concentrations not matching the laboratory standard <br /> were identifietl as Stoddard solvent or paint thinner. The before and after groundwater concentrations are from MW-1A the <br /> most contaminated, down-gradient data point. Neither 1,2 DCA nor EDB have been detected in soil or groundwater <br /> samples'analyzed. 400 cubic yards of soil were excavated and 206,500 gallons of water were extracted during interim <br /> remediation at this site. Groundwater contaminant concentrations have declined over time. Compliance with the Public <br /> Participation requirements in Section 2728 of the California Code of Regulations has been met. <br /> IV. Closure <br /> Does completed corrective action protect existing beneficial uses per the Regional Board Basin Plan? Yes <br /> Does completed corrective action protect potential beneficial uses per the Regional Board Basin Plan?Yes <br /> Does corrective action protect public health for current land use? Yes <br /> Site management requirements: NA <br /> Should corrective action be reviewed if land use changes? Yes <br /> MonitoringNapor wells decommissioned: Yes Number Decommissioned: 3 Number retained: 0 <br /> List enforcement actions taken: NOR'sent to RP <br /> List enforcement actions rescinded: NA <br /> V. Local Agency Representative Data <br /> Name: Donna Heran, REHS Title: Director <br /> Signature: � � �} Date: —vi- <br /> VI. <br /> ate: r f 7 � i- <br /> L � <br /> VI. Central Valley Regional Water Quality Control Board R8 Notification <br /> Date Submitted to RB: Response Date: 01/24/08 <br /> RB Staff: J. Barton Response: Concurrence <br /> Title: Eng. Geologist <br /> VII. Additional Comments, Data, etc. <br /> This document and the related CASE CLOSURE LETTER, Shall be retained by the lead agency as part of the official <br /> site file.: <br />