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FIRST QUARTER,2003 GROUNDWATER MONITORING REPORT JAMAR OIL DISTRIBUTION NNE 2003 Toluene was detected in samples collected from MW-1 MW-2, MW-3 and MW-4 at 1,700 gg/l, 63 gg/l, 55 gg/l and 56 gg/l, respectively. Ethylbenzene was detected in the samples collected from MW-1, MW-2, MW-3 and MW-4 at 250 gg/l, 14 gg/l, 10 gg/l and 6.1 gg/l, respectively. Total xylenes were detected in samples collected from MW-1, MW-2, MW-3 and MW-4 at 610 gg/l, 49.4 gg/l, 86 gg/1 and 210 gg/l, respectively. MTBE was detected in samples from wells MW-1 through MW-5 at concentrations of 150,000 gg/l, 180 gg/l, 59 Vg/l, 7,800 gg/l, and 2.4 µg/1, respectively. Tertiary butyl alcohol(TBA) was detected in the sample collected from MW-1 at 3,700 µg/1. DIPE, ETBE, and TAME were ND in all samples taken this quarter. 1,2 DCA was detected in samples from wells MW-1,MW-2 and MW-4 at 2,100 gg/l, 89 gg/l and 210 gg/l. Groundwater analytical data are summarized in Table 2 and shown on Figure 6. Copies of the laboratory reports with COC documentation are included in Appendix B. CONCLUSIONS . The majority of constituent concentrations in the groundwater increased this quarter, however, the concentrations were generally lower than historical levels. The CPT/geopbove investigation has further defined the downgradient extent of MTBE-impacted groundwater. SCHEDULE The next quarterly monitoring event is scheduled for June 2003. The First Quarter 2003 Monitoring Report will be submitted by July 31, 2003. GHH is currently investigating the availability of a limited access drill rig to drill and complete the new monitoring wells. Because both the locations are in the sidewalk on either side of Main Street, and there are overhead lines running along both sides of the street, a limited access drill rig will be required. GHH will install these new wells as well as the groundwater extraction well upon regulatory approval. The two monitoring well clusters (MW-6 and MW-7) and the on-site extraction well proposed by GHH have received regulatory approval and will be installed in May 2003. GHH will also perform a sensitive receptor survey of all nearby water supply wells and those within 2,000-feet of the site, as well as surface water sources and other sensitive receptors in accordance with . Section 2654(b)(2), Article 5, Chapter 16, Division 3, Title 23 of the California Code of Regulations. 5