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Monitoring Well Installation Report Quik Stop No 121 Page 7 horizon becomes more granular, consisting of sand to approximately 19 feet, with the exception of a three foot clay lense between 14 and 17 feet in MW-3 (see cross-section Figure 3) Between 17 and 22 feet, a sandy silt to silt was encountered, followed by a silty clay between 22 and 25 feet Groundwater was encountered at approximately 15 to 18 feet during the course of the investigation CCI submitted a total of 9 soil samples for analysis of petroleum hydrocarbons The laboratory reported all 9 soil samples to be free of detectable TPHg and BTEX compounds The 9 soil samples were reported to contain detectable concentrations of MTBE, as high as 88 ug/kg The MTBE contamination was detected throughout the soil column in the three wells, from a depth of 5 feet in MW-2 to 20 feet in both MW-1 and MW-3 Laboratory analyses of groundwater samples collected from a total of three on-site wells were reported to have low levels of petroleum hydrocarbons but no detectable concentrations of any fuel oxygenates During the sampling of the monitoring wells(MW-1,MW-2 and MW-3), no petroleum odors were noted in the purge water Groundwater measurements taken in the three monitoring wells on April 3 0, 1999 indicated that depth-to-water ranged from approximately 13 24 to 14 02 feet below the top of the well casings Groundwater contours indicated the groundwater surface to be essentially flat, with a very slight gradient to the northeast, at an approximate gradient of 0 01 feet/foot(Figure 4) The difference in water elevation among the three wells is only 2 tenth of a foot Using the water level measurements from the well development on April 26, 1999 also produces a very flat groundwater gradient to the northeast Conclusion and Recommendation Based on the laboratory data collected during the investigation, it appears the groundwater has been slightly impacted with low levels of petroluem hydrocarbons at the subject site No fuel oxygenates were detected in the samples from the three wells With a relativley flat groundwater gradient at the subject site,the low levels of groundwater contamination detected in the three wells appears to be localized It appears that a majority of the soil and groundwater contamination discovered during the removal of the fuel tanks in March 1998 have substantially dissipated over time CCI recommends that quarterly groundwater monitoring be initiated at the site to monitor groundwater contaminant levels at the site and to monitor the groundwater flow direction over time No further investigation is recommended at this time Reporting Requirements Quik Stop Markets should forward a copy of this report to the following agency in a timely manner