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FO 00 . FOURTH QUARTER,2 2 GROUNDWATER MONITORING REPORT AND ADDITIONAL ASSESSMENT REPORT JAMAR OIL DISTRIBUTION MARCH 2003 The groundwater samples were analyzed for TPH G and TPH D using EPA Method 8015 Modified and for BTEX, 1,2-DCA, EDB and the fuel oxygenates DIPE, ETBE, MTBE, TAME, and TBA using EPA Method 8260B The analyses were conducted by SunStar Laboratones Inc , a California State certified laboratory, in accordance with state guidelines and EPA protocol SUMMARY Fourth Quarter 2002 Groundwater Flow and Gradient Based on depth to groundwater measurements taken on December 19, 2002, the depths to groundwater range from 63 99 feet below ground surface (bgs) ,n monitoring well MW-1 to 64 42 feet bgs in MW- 4 All groundwater elevations were measured to the nearest 0 01-foot relative to the surveyed top of casing elevation The elevations are based on the survey conducted by JPCA on August 30, 2000 The survey on August 30, 2000 was completed by setting the corner of the cement sidewalk on the southeastern corner of the store as the . benchmark with an assumed elevation of 30 feet above mean sea level(MSL) Based on the surveyed casing elevations and the measured depth to water on December 19, 2002, the groundwater elevations range from-3 5 72 feet in MW-5 to -3 5 91 feet in MW-4 The direction of groundwater flow has been calculated to be trendinguth-southe t with a relatively flat hydraulic gradient of approximately 0 0008-feet/foot acro the si Calculated groundwater elevations are summanzed in Table 1, and shown on Figure 5 Fourth Quarter 2002 Groundwater Analytical Results TPH G was detected in samples from monitoring wells MW-1 and MW-4 this quarter at concentrations of 2,800 rrucrograms per Mer(pg/l) and 1,000 µg11, respectively TPH G was ND in MW-2, MW-3 and MW-5 TPH D was not detected in any of the wells this quarter Benzene was detected in samples from wells MW-1 through MW-4 at concentrations ranging from 38,000 pg/l, in the sample from MW-1, to 90 µg/1 in the sample from MW-3 Toluene was detected in samples collected from MW-1, MW-2, and MW-4 at 160 µg/l, 6 0 gg/l and 11 pg/l, respectively Ethylbenzene was detected in the sample collected from MW-1 at 51 µg/1 Total xylenes were detected in samples collected from MW-1, MW-3 and MW-4 at 136 µg/1, 5 4 µg/1 and 35 µg/1, respectively MTBE was detected in samples from MW-1 and MW-4 at concentrations of 190,000 pg/l, and 150 pg/l, respectively Tertiary butyl alcohol (TBA)was detected in the sample collected from MW-I at 440 µg/1 DIPE, ETBE, and TAME were non-detect in all samples taken this quarter a