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Fust Quarter 2006 Quarterly Groundwater Monitoring Report 4 Raymond investment Corporation,Stockton,CA Page 2 of 4 samples), and water quality field parameters No sheen was noted in either well, a moderate hydrocarbon •) odor was noted in monitoring well MW-2 Field observations are included on the Groundwater Monitoring Field Forms, attached GROUNDWATER ELEVATIONS AND GRADIENT -The average groundwater elevation in the monitoring wells was -17 39 feet, an increase of 1 79 feet since the previous sampling event conducted on November 18, 2005 The estimated groundwater gradient for _,,y the Site was 0 0055 ft/ft_to the east-northeast-and is shown on Figure 3„attached _Monitoring well groundwater elevation data are presented in Table 1, below Historic groundwater elevation data are F presented in Table A, attached Table 1 Groundwater Elevation Data (March 9, 2006) Well I.D. TOC Screened Depth to Groundwater Elevation' Interval (b s) Groundwater Elevation2 MW-1 1635 32-47 3364 -1729 T MW-2 1652 _ 32-47 3392 -1740 r- MW-3R 15 78 32-47 3327 -1749 11 } 5 'TOC Elevation referenced to NAVD88 vertical datum 2Groundwater Elevation Elevations are measured from the top of the well casings and are referenced to the benchmark indicated above All measurements are m feet LABORATORY ANALYTICAL RESULTS Ms McCartney of the SJCEHD approved the removal of total petroleum hydrocarbons quantified as kerosene (TEPH-K) and motor oil (TPH-MO), methanol, ethanol, tertiary-butyl alcohol (TBA), di- isopropyl ether (DIPE), tertiary-amyl methyl ether (TAME), ethyl tertiary-butyl ether (ETBE), 1,2- dichloroethane (1,2-DCA), and 1,2-dibromoethane (EDB) from the analytical list of compounds for the three monitoring wells in her letter dated February 22, 2006 As mentioned above, Ms McCartney also recommended reducing sampling of monitoring well MW-3R from quarterly to annually Groundwater samples collected from MW-1 and MW-2 were analyzed for benzene, toluene, ethyl benzene, and total xylenes (BTEX) and methyl tertiary-butyl ether (MTBE) by EPA Method 8260B, and for total petroleum hydrocarbons quantified as gasoline (TPH-G) and total extractable petroleum hydrocarbons quantified as diesel (TEPH-D) by EPA Method 8015M Groundwater samples were analyzed by Argon Laboratories, Inc of Ceres, California The current groundwater sample laboratory analytical results are presented in Table 2, on the following page Historic groundwater monitoring data are presented in Table A, attached _ • �� CONDOR