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Y <br /> C A M B R I A <br /> Cambria researched the subject site at the State Water Resources Control. Board's Geotracker <br /> website. According to information provided on the website, there are no public water wells <br /> estimated to be near the subject site.F w <br /> No other sensitive receptors were identified. The locations of the wells identified during this <br /> survey are shown on Figure 1 and the known details for these wells are included in Table 4. i <br /> CONCLUSIONS <br /> The purpose of this investigation was to;further assess the lateral and vertical extent of gasoline <br /> constituents in soil and groundwater beneath the site. Three monitoring wells were installed and <br /> -one CPT boring was drilled as part of this investigation. <br /> The investigation findings indicate that no TPHg or benzene are present in soil or groundwater <br /> beneath the site. Only MTBE was detected in some of the soil samples collected during this <br /> investigation. These detections of MTBE were in saturated soil samples and are likely the result <br /> of horizontal migration of impacted groundwater rather than the result of vertical migration from <br /> vadose soils. The highest levels of MTBE in soil were detected in soil,samples from MW-6 <br /> which is located downgradient of well.MW-1. Well MW-1 has contained the highest levels of <br /> MTBE in groundwater to date at this site. <br /> Soil samples from deep boring SBA contained MTBE at depths of 20, 30, 60, 80, and 86 fbg,_ <br /> however water samples from SB-1 collected at 52, .72, and 82 fbg did not contain MTBE. It is <br /> possible that the MTBE detected in the soil samples does not accurately reflect soil condition at <br /> depth. The soil samples were collected all from the same CPT boring where impacted shallow <br /> groundwater could:have been introduced to the deeper sediments during the sampling process. <br /> However, the grab groundwater samples were collected from three separate borings in order to <br /> minimize cross contamination. We believe the grab groundwater data more accurately represents <br /> condition at depth beneath the site than the soil data does. <br /> Based on the above data and analysis we believe the vertical and lateral extent of gasoline <br /> constituents in soil is defined at the site. <br /> Cambria will evaluate the groundwater sampling data from the new and existing wells in the <br /> second quarter 2005 groundwater monitoring report to be issued during June 2005 to determine <br /> the status of lateral delineation of the plume. <br /> 1661 7 <br />