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C A M B R I A �I THIRD QUARTER 2002 GROUNDWATER MONITORING Blaine gauged and sampled the site wells and prepared a summary table of field gauging data and laboratory analytical results The pre-existing wells were sampled on August 23, 2002 and the new wells were sampled on September 27, 2002 Cambria compiled the additional constituents and oxygenates (Table 2)prepared a groundwater contour/chemacal concentration map(Figure 2) utilizing the gauging data collected September 27, 2002 from all site wells The new wells were not used for contouring as they were installed in a line which does not allow for triangulation needed for creating groundwater contours We plan to coordinate future sampling events with the ARCO site across West Charter Way, which has deep screened wells also With groundwater elevation data from their deep screened wells we will be able to contour the deep groundwater zones Blaine's report,presenting the laboratory report, is included as Appendix D CONCLUSIONS The goal of this investigation was to install wells to monitor deeper groundwater zones beneath the site where hydrocarbons had previously been detected Six wells were installed to monitor . groundwater at approximately 70 to 80 fbg and 110 to 120 fbg We compared the groundwater sampling results of the newly installed wells with the grab groundwater sample data collected at similar depths from previous investigations at this site These data are shown on Figure 3 The groundwater analytical data from the newly installed wells correlates well with the grab groundwater sample data collected from soil borings drilled during previous investigations As was evident from previous investigation results, the concentration of hydrocarbons detected in the new wells declines with depth The concentration of hydrocarbons in the 110 to 120 fbg screened wells is lower than the concentrations of the corresponding 70 to 80 fbg screened wells We evaluated groundwater elevation data from shallow wells and deeply screened wells (above table) and it appears that there is a downward vertical gradient beneath this site The wells with deep screened intervals have groundwater elevations that are lower than the wells with shallow screens 1399 6