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Mr Ron Rowe Proposal 22613-100 002 • January 30, 1998 Page 2 diesel (TPHD), and benzene were below laboratory detection limits The approximate UST locations relative to site structures are shown on Figure 2 In the vicinity of the subject property is a former ARCO Service Station, a Chevron Service Station, a Texaco Service Station, a former Colombo bakery, and a former Dolly Madison facility, which all previously or currently have USTs Based on data collected from subsurface investigations performed at the former ARCO Service Station, Chevron Station, and Texaco Station (located at the corners of Charter Way and Lincoln Street), residual and dissolved hydrocarbons have been detected beneath these facilities, and a commingled plume exists beneath Charter Way and Lincoln Street. Between September 17 and October 11, 1996, EMCON observed the drilling of six soil borings (B-1R through B-6R) One soil boring was converted to monitoring well MW-1R, three soil borings were converted to dual completion vapor extraction wells VW-1 through VW-3, and one soil boring was converted to a single vapor extraction well VW-4 (EMCON, Preliminary Investigation and Evaluation Report, February 5, 1997) The results of this investigation indicated the following ® The majority of residual hydrocarbons were detected in the vicinity of the former USTs and dispenser islands. Residual hydrocarbons were detected in each boring, except from soil samples collected from boring B-6R The highest concentrations were detected approximately 10 feet below ground surface (bgs) near the former USTs (TPHG detected at 11,000 parts per million [ppm] in boring B4R) Total oil and grease was detected in the soil sample collected near the former UST cavity (located near the building) at a concentration of 10,000 ppm Polychlonnated bi-phenyls, TPHD, and chlorinated hydrocarbons were below laboratory detection limits in all soil samples analyzed from soil borings B-2R and B-6R a Groundwater was encountered at approximately 31 to 38 feet bgs On September 30, 1996, static groundwater was measured at 26 44 feet bgs in monitoring well MW-1R Groundwater elevation is consistent with groundwater elevations measured at adjacent properties o TPHG, benzene, toluene, ethylbenzene, and total xylene (BTEX) isomers, and methyl tert-butyl ether (MTBE) compounds were detected in monitoring well MW-1R. TPHG and benzene were detected at concentrations of 33,000 parts per billion (ppb) and 1,400 ppb, respectively MTBE was detected at a concentration of 550 ppb • SAC,N\P72\2613\2.6131000 2A$-984baccus 3