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C A M B R I A Site Investigation* Five groundwater monitoring wells (MW-2 through MW-6) are proposed at the locations shown on Figure 2 The exploratory bonngs will be drilled using hollow-stem auger equipment and the bonngs will be converted to groundwater monitoring wells The purpose of the wells is to further assess the extent of impacted soils and groundwater previously identified in the vicinity of the USTs and the northwestern product dispensers Well MW-2 is proposed near the USTs and MW-3 is proposed adjacent to the northwestern dispenser These wells are located near potential source areas, and will assess the vertical extent of petroleum hydrocarbons and fuel oxygenates in soil Proposed wells MW4 through MW-6 are placed to investigate the lateral extent of petroleum constituents in soil and groundwater beneath the site First encountered groundwater, based on the October 2001 investigation, is approximately 60 fbg A Cambria geologist will supervise the drilling and describe encountered soils using the Unified Soil Classification System and Munsell Soil Color Charts Soil samples from the borings will be collected at five-foot intervals for lithologic description and possible chemical analyses Soil samples will be screened in the field for organic vapors using a photo-ionization detector (PID) Exploratory boring logs will be prepared for each of the wells PID measurements will be recorded on the boring logs Soil samples designated for chemical analysis will be retained in stainless steel or brass sample tubes The tubes will be covered on both ends with Teflon sheets and plastic end caps Soil samples will be labeled, entered onto a chain-of-custody record and placed into a cooler with ice for transport to a State of California certified laboratory for analyses The wells will be completed using four-inch diameter Schedule 40 PVC casing Each well screen interval will be approximately five feet above and ten feet below first encountered groundwater The sandpack will be placed two feet above the top of the well screen followed by a two-foot thick bentonite seal and cement grout to grade Actual well construction details will be based on field conditions at the time of drilling The wells will be secured with a locking cap under a traffic-rated well box A licensed surveyor will survey wellhead elevations relative to mean sea level and the well locations relative to latitude and longitude At this time, Cambria is not proposing interim remediation because it has not been demonstrated that there are "persistent concentrations of MTBE over 10,000 ppb" at this site as discussed in Step 3 of the State Water Resources Control Board Guidelines for Investigation and Cleanup of MTBE and Other Oxygenates (March 30, 2000) Data collected from the proposed monitoring wells will assist us in evaluating the need for interim remediation at this site 0953 3 ' ` I