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29 November 2001 - <br /> r AGE-NC Project No 95-0111 <br /> • Page 4 of 4 <br />' • The northerly ground water flow direction inferred from, data collected during this <br /> monitoring event is consistent with ground water flow directions determined during past <br />' morutonng events at the site <br /> • TPH-d was detected in the ground water samples collected from wells MW-4 and MW-5 at <br />' concentrations of 2,700 µg/1 and 1,100 µg/1, respectively TPH-d concentrations increased <br /> in the sample from MW-4 and decreased in the sample collected from MW-5 compared to <br /> the previous sampling event <br />' • MTBE was detected in samples from four wells(MW-1,MW-2,MW-7 and MW-8)with the <br /> highest concentration (17 µg/1) occurring immediately down-gradient and slightly oblique <br /> to the UST facility (MW-1) MTBE concentrations, with the exception of the sample <br />' collected from MW-1,are below the State of California primary maximum contaminant level <br /> (MCL)of 13 µg/1 A map illustrating the approximate extent of TPH-d-and MTBE-impacted <br /> ground water is depicted on Figure 4 <br /> • The laboratory results of the microbiological analysis indicate low to moderate populations <br /> of organisms capable of gasoline and diesel metabolism However, nutrient concentrations <br />' are at moderate to high levels for ongoing bioremediation <br /> 4 <br /> lie 5.0. RECOMMENDATIONS <br />' - Based on the findings of this investigation, AGE recommends <br /> • Continued quarterly ground water monitoring of the wells on-site The next monitoring event <br />' should be scheduled for December 2001 <br /> • Analysis of ground water samples for 1,2-dichloroethane and ethylene dibromide <br /> 6.0. LIMITATIONS <br /> Our professional services were performed using that degree of care and skill ordinarily exercised by <br /> environmental consultants practicing in this or similar localities The findings were based upon <br />' analytical results provided by an independent laboratory Evaluations of the geologic/hydrogeologrc <br /> conditions at the site for the purpose of this investigation were made from a limited number of <br /> available data points (i a ground water monitoring well samples) and subsurface conditions may <br />' vary away from these data points No other warranty, expressed or implied, is made as to the <br /> professional recommendations contained in this report <br /> r <br /> Advanced GeoEnvironmentai Inc <br /> s <br /> t <br /> I <br />