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51 tx Soil and Groundwater Investigation Page 2 Former Dolly Madison Facility Project No 2002-1426-02 October 27, 2000 zone Analytical results of groundwater indicated dissolved hydrocarbons were detected in monitoring wells MW-1 and MW-2 (EMCON, August 4, 1997) TPHG was detected in monitoring wells MW-1 and MW-2 at concentrations of 18,000 parts per billion (ppb) and 220 ppb, respectively Benzene was detected in monitoring wells MW-1 and MW-2 at concentrations of 4,400 and 33 ppb, respectively In the vicinity of the Site are a former ARCO Service Station, a Chevron Service Station, a Texaco Service Station, The Transmission Shop, and a former Colombo Bakery facility, all of which have or previously had UST's Based on data collected from subsurface investigations performed at these sites, residual and dissolved hydrocarbons � have been detected beneath these facilities, and a co-mingled plume of dissolved petroleum hydrocarbons exists beneath the intersection of Charter Way and Lincoln Street Data gathered from the former Colombo Bakery facility and the Texaco Station suggest that hydrocarbon impact extends greater than 100 feet bgs It is our understanding that the groundwater flow direction near the intersection has generally been toward the east and northeast SITE INVESTIGATION ACTIVITIES . The purpose of this investigation was to evaluate the vertical extent of petroleum hydrocarbons beneath the site To accomplish this objective, Stratus initiated the following activities • Advanced two (2) Cone Penetration Test (CPT) soil borings (CPT-1B-4 and CPT-2B-5) south of the existing building in the vicinity of the former UST location to a depth of 120 feet bgs, and • Advanced four (4) direct push soil borings, two directly adjacent to each CPT boring, to collect soil and groundwater samples Prior to initiating field activities, permits to advance the soil borings were obtained from PHS/EHD Soil borings were marked and Underground Service Alert (USA) was contacted 48 hours prior to work activities PHS/EHD was subsequently notified of the work schedule On May 26 and May 30, 2000, a Stratus geologist monitored Gregg Drilling & Testing, Inc of Martinez, California advance the soil borings All work was performed under the direction of a California Registered Geologist CPT soil borings were advanced at two locations (CPT-1B-4 and CPT-2B-5) to obtain a continuous log of the subsurface lithology (see Figure 2) The logs were subsequently used to decide soil and groundwater sampling depths CPT-1/B-4 was located adjacent to B1/VW-1 and close to the former UST tank cavity CPT-2B-5 was located near B3/MW-2, east (downgradlent) of the former UST location The total depth of each CPT boring was approximately 120 feet bgs P V B C\Stockton%Reports\lBC Soil and Groundwater report Oct 2000 doe STRATUS