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CAMBRIA HYDROCARBON DISTRIBUTION IN GROUNDWATER Cambna collected groundwater samples from boring CPT-1 at approximate depth intervals of 35-39 fbg, 50-54 fbg, 74-78 fbg, 82-86 fbg, 104-108, and 111-114 fbg No TPHg, BTEX, or lead scavengers were detected in groundwater samples from boring CPT-1 MTBE was detected in groundwater samples from every depth interval in boring CPT-1 at concentrations ranging from 12 to 81 Parts per billion (ppb) TBA was detected in the groundwater sample collected from 111-114 fbg at a concentration of 51 fbg No other fuel oxygenates were detected from boring CPT-1 TPHd was detected in groundwater samples from boring CPT-1 at concentrations ranging from 140 to 340 ppb The laboratory noted that the hydrocarbons reported as diesel do not exhibit a typical diesel chromatographic pattern Therefore these results may be anomalous The groundwater chemical analytical data are summarized on Table 3 and shown on Figure 2 The certified analytical report is presented in Appendix B . CONCLUSIONS One exploratory soil boring (CPT-1) was drilled dunng this investigation to assess the vertical extent of impacted soil and groundwater beneath the site Soil sampling analytical results from boring CPT-1 indicate the vertical extent of gasoline and diesel constituents in the soil beneath the site is defined as no gasoline or diesel constituents were detected below 10 fbg TPHd was detected in groundwater samples collected from boring CPT-1, however, the laboratory noted that the hydrocarbons reported as diesel do not exhibit a typical diesel chromatographic pattern Therefore,these results may be anomalous Additionally, the concentration of TPHd and MTBE detected in every groundwater sample from boring CPT-1 is relatively the same Since the concentrations remain relatively constant as the sample depth increases, this suggests that there may have been mixing of shallow impacted groundwater with deeper zone groundwater during drilling and/or sampling activities We have seen similar anomalies at other sites where we have performed vertical extent investigations in, or near, the source area where shallow groundwater is impacted with gasoline constituents The former water supply well (RW) at this site was located approximately 18 feet away from . boring CPT-1 (Figure 2) Prior to properly destroying well RW we collected a groundwater 0813 5