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' Mr Kyle Christie Project 0805-146 01 December 16, 1994 ' Page 2 1'0 monitoring well MW-2 Fecal and total coliform bacteria were not detected in the sample collected ' from well MW-3 In January 1993, RESNA observed drill of seven soil borings and the installation of two ' groundwater`� onitoring wells and four✓Vapor extraction wells Results of this assessment were reported in RESNA's first quarter 1993 status report (RESNA, June 9, 1993, Report 31009-7) Analytical data indicated that hydrocarbons present in soil below 26 feet and in groundwater were ' probably from an off-site source Therefore, ARCO requested that an investigation of soil and groundwater be performed off site and upgradier� o�f the ARCO station to evaluate whether hydrocarbons were present upgradient of the site !¢1cac��Cku�co+� In October 1 93, RESNA observed drilling of two soil bonngs and the installation of two ' groundwater monitoring wells (MW-6 and MW-7) Analytical data indicated that residual and dissolved hydrocarbons are present in wells MW-6 and MW-7 (RESNA, February 15, 1994, Report 31009-9) GROUNDWATER MONITORING THIRD QUARTER 1994 Groundwater Technology, Inc , (GTI) of Concord, California, was contracted by ARCO to conduct the field work at the site, GTI subsequently forwarded their field notes and the laboratory reports to ' EMCON Field work included measuring depths to water and collecting groundwater samples for subjective and laboratory analyses EMCON used these data to evaluate the direction and gradient of groundwater flow beneath the site ' On September 26 1994, a technician from GTI measured depths to water and collected groundwater samples from wells MW-1 through MW-7 for subjective and laboratory analyses Floating rodu or product sheen was no notedsri samples from the wells (see Table 1) The wellhead elevations of the site monitoring wells were previously surveyed by Tom O Morrow Inc The surveyed elevations and the depth to groundwater measurements, summarized in Table 1, were used to evaluate the potentiometric surface beneath the site The direction of groundwater flow on September 26, 1994, wa rtheast with a hydraulic gradient of�� as shown on Figure 2 The gradient is consistent with pervious data Groundwater elevations have decreased approximately 123 feet since the last sampling event (June 1994) ' Groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPHG) using Environmental Protection Agency (EPA) Methods 5030/8015 and benzene, toluene, ethylbenzene and ' total xylenes (BTEX) using EPA Methods 5030/8020 prescribed by the state of California Samples were also analyzed for halogenated vo organic compounds (HVOCs) using EPA Methods 5030/ , and the samples from we MW-2 were analyzed for TOG using Standard ' Methods (SM) 5520C and 5520F These samples were analyzed at National Environmental Testing, SA(/PJM80M8051460 WS-94 PAs 2