SITE INFORMATION AND CORRESPONDENCE

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sem. Case Closure Summary Page i12 Legg Underground Fuel Storage Tank ProgrU III Release and Site Characterization Information continued Maximum Documented Contaminant Concentrations -- Before and After Clir eanup Contaminant Soil Before Soil Water Water Contaminant soil Soil Water Water 11(ppm) After Before After Before After Before After (Ppm) r (0'P' (ppm) <002 TPH(Gas) 1,900 41.0 30.6 <.050 MTBE <0.5 <0.005 .0125 ---- Benzene 0.075 <0.005 .02 <.0005 Lead 40.5 15 Toluene 7.3 <0.005 1.4 <.0005 EDB 0:0041 4.002 Ethylbenzene 18 <0.005 .484 4.0005 1,2-DCA ' w'k ____ ---- 4.002 Xylene 120 <0.005 6.06 <.0005 TEPH i 5000 I k I� "Soil Before" levels are from MW1 at 10.5 feet in February 1999, except TEPH which is diesel contamination in the soil sample collected at 3 feet along the fill line at the time of the tank pull in 1990. "Water Before" levels are from August 1997 grab water sample from a boring, except MTBE which is from MW 1 in February11999. "Soil After"levels are from the monitoring wells installed in February 2001. "Water After" levels are from jthe monitoring wells on 3/4/02. i Results of soil samples from subsequent investigations of the both diesel UST and the remote fill line in August 1997 were all no : detect. Only MW-1 groundwater samples had minor levels of BTEX contamination between 1999 and 2000. Results of groundwater samples from all five wells have fallen to non-detect levels over the`last 4 quarterly monitoring events in 2001 and 2002. Investigation showed minimal impact to soil and groundwater. Beneficial uses of groundwater are protected, now and in the future. IV. Closure i Does completed corrective action protect existing beneficial uses per the,Regional Board Basin Plan? Yes Does completed corrective action protect potential beneficial uses per the Regional Board Basin Plan? Yes Does corrective action protect public health for current land use? Yes ,p Site management requirements: none I Should corrective action be reviewed if land use changes? Yes Monitoring wells decommissioned: No Number Decommissioned: 0 Number retained: 5 List enforcement actions taken: NOR sent : List enforcement actions rescinded: None P ` V. Local Agency Representative Data ' � ilE Name: Margaret Lagorio Title: Supervising REHS/Site Mitigation/LOP Unit IV Signature: Date: p ;l VI. Central Valley Regional Water Quality Control Board (RB) Notification - Date Submitted to RB: November 6, 2002 Response Date: 1 RB Staff: Marty Hartzell Response: I Title: Assoc Eng Geologist i VII. Additional Comments,Data, etc. -g - Destruction of MW-1 to MW-5 must occur prior to final closure. This document and the related CASE CLOSURE LETTER,Shall be retained by the lead agency as part of the official site file. (08/24/93) Exhibit N Page 2 of 2 I`