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r. Mr Kyle Christie Project 0805-142 003 April 27, 1995 Page 2 GROUNDWATER MONITORING: FIRST QUARTER 1995 EMCON was contracted by ARCO to conduct the field work at the site 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 February 12, 1995, a technician from EMCON measured depths to water and collected groundwater samples from wells MW-1 through MW-3 for subjective and laboratory analyses Floating product or product sheen was not noted in samples from the wells (see Table 1) Field Procedures are presented in Attachment A The well head elevations of the monitoring wells at the site were previously surveyed by Tom O Morrow The surveyed elevations and the depth to groundwater measurements (summarized in Table 1) were used to evaluate the potentiometric surface beneath the site The groundwater flow direction on February 12, 1995, was to the south with a hydraulic gradient of 0 002 (see Figure 3) Groundwater elevation data are presented on Figure 3 and in Table 1 Groundwater elevations increased approximately 1 40 feet from the previous sampling event (December 1994) Groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPHG), total petroleum hydrocarbons as diesel (TPHD) using Environmental Protection Agency (EPA) Method 5030/DHS LUFT, total oil and grease (TOG) using EPA Method 5520 B and F, and benzene, toluene, ethylbenzene, and total xylene (BTEX) isomers using EPA Methods 5030/8020 These samples were analyzed at Columbia Analytical Services, Inc , in San Jose, California The results of analyses are summarized in Table 1 Copies of the laboratory analysis reports are presented in Attachment B TPHG concentrations were detected in all wells, concentrations ranged from 130 parts per billion ([ppb] well MW-2) to 290 ppb (well MW-1) Concentrations of benzene were not detected at laboratory detection hrruts in all wells TOG was not detected in groundwater samples collected from all wells TPHD was detected in well MW-1 at a concentration of 526 ppb, but was not detected at laboratory detection limits in the other wells TPHG and benzene concentrations are shown on Figure 2 ACTIVITIES PERFORMED DURING THE FIRST QUARTER Miguel Guerrero (property owner west of the site) was contacted in March 1995 by an EMCON representative regarding the access agreement form sent to lum on October 24, 1994, and January 25, 1995, for the installation of one vapor extraction well on his property However, EMCON has not received the signed SAC1N 1PJ010805108051420 3AL-941dms I I