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n <br /> Mr Kyle Christie Project 0805-144 02 <br /> November 21, 1995 <br /> � Page 2 <br /> GROUNDWATER MONITORING. THIRD QUARTER 1995 <br /> EMCON was contracted by ARCO to monitor the groundwater in the monitoring wells <br /> previously installed at the site Field work included measuring depths to groundwater and <br /> collecting groundwater samples for subjective and laboratory analyses EMCON used these data <br /> to evaluate the gradient and direction of groundwater flow beneath the site <br /> On August 11, 1995, a technician from EMCON took water level measurements and collected <br /> groundwater samples from monitoring wells MW-1 through MW-4 for subjective and laboratory <br /> analyses The technician did not observe floating product or product sheen on samples collected <br /> from the wells (see Table 1) Sampling and analysis procedures are presented in Appendix A <br /> The surveyed elevations of the top of casing and the depth-to-groundwater measurements (see <br /> Table 1) were used to evaluate the potentnometnc surface beneath the site On August 11, 1995, <br /> the direction of groundwater flow was toward the northwest with a gradient of approximately <br /> 0 01 (see Figure 3) The direction of groundwater flow is consistent with previous sampling <br /> events Groundwater elevation decreased approximately 0 62 foot from the previous sampling <br /> event (May 1995) <br /> Groundwater samples from each well were analyzed for total petroleum hydrocarbons as gasoline <br /> (TPHG), and benzene, toluene, ethylbenzene, and total xylenes (BTEX) using California <br /> Department of Health Services LUFT Method and Environmental Protection Agency Method <br /> 5030/8020, respectively The samples were analyzed at Columbia Analytical Services, Inc , in San <br /> Jose, California- The results of analyses are summarized in Table 1 Copies of the chain-of- <br /> custody <br /> hain-ofcustody records and laboratory analysis reports are presented in Appendix B Results of analyses <br /> indicated TPHG and BTEX concentrations were below laboratory detection limits in groundwater <br /> samples collected from wells MW-1 through MW-4 <br /> ACTIVITIES PERFORMED DURING THE THIRD QUARTER <br /> • EMCON performed quarterly groundwater sampling <br /> • EMCON compiled and evaluated groundwater monitoring data <br /> ANTICIPATED WORK <br /> • ARCO will continue to perform quarterly groundwater monitoring The next sampling <br /> event is tentatively scheduled for November 1995 <br /> SA"�PJW8oSAg0514402CS-9Spas i <br />