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t d , DISCUSSION In the uppermost portion of the water-bearing zone, petroleum hydrocarbons were detected in the samples collected from wells MW-1 through MW-7 The highest TPHG concentration (32,000 µg/L) was detected in the sample collected from well MW-6, and the highest benzene concentration (6,900 pg/L) was detected in the sample collected from well MW-3 Benzene (5 8 and 4 9 µgfL, respectively) were detected in the samples collected from both mid-depth wells MW-1 B and MW-8B Benzene (10 and 120 µg/L, respectively), was also detected in the samples collected from deepest screened wells MW-1C and MW-8C MTBE was detected in the samples collected wells MW-1 (29 µg/L), MW-8B (1 1 µg/L), and MW-8C (1 3 µg/L) 1,2-DCA was detected in the samples collected from wells MW-1, MW-1B, MW-1 C, MW-2, MW-8, and MW-8B at concentrations dust above laboratory reporting limits Concentrations of petroleum hydrocarbons and fuel additives detected during the first quarter 2002 sampling event are generally consistent with previous analytical results The groundwater flow direction for February 14, 2002 was calculated to be towards the east-southeast at an average gradient of 0 0026 ft/ft Groundwater elevations in the monitoring wells increased approximately 1 0 to 1 6 feet since the previous sampling event (December 2001) ATTACHMENTS • Table 1 Groundwater Monitoring Data • Table 2 Groundwater Analytical Results for Oxygenates • Table 3 Historical Groundwater Flow Direction and Gradient • Figure 1 Site Location Map • Figure 2 Groundwater Elevation Contour Map (First Quarter 2002) • Figure 3 Groundwater Analytical Summary Map (First Quarter 2002) Appendix A Field Data Sheets • Appendix B Sampling and Analysis Procedures • Appendix C Certified Analytical Reports and Chain-of-Custody Records • P 1ARCO121681QTRLY\20021Arco_2168_1 Q02 doc Delta