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5 4.0 SUMMARY OF RESULTS ' A summary of the analytical results from current and past well sampling is presented in Table 1. Based on the water-level data for May 22, 2001, ATC has interpreted the groundwater gradient and flow direction for the upper aquifer as shown on Figure 3. In the upper aquifer (monitoring wells MW-5, MW-6, and MW-7), the groundwater elevation increased from the previous .� quarter an average of 0.73 feet, ranging from 0.068 feet in monitoring well MW-7 to 0.76 feet in monitoring well MW-6. The apparent groundwater flow direction in the upper aquifer was southeasterly at a gradient of approximately 0.0056 (Figure 3). Based on the water-Ievel data for May 22, 2001 (Table 1), ATC has interpreted the groundwater gradient and flow direction for the lower aquifer as shown on Figure 4. In the lower aquifer (monitoring wells MW-1R, MW-2, MW-3, MW-4 and MW-8), the groundwater level increased from the previous quarter an average of 0.56 feet, ranging from 0.81 feet in monitoring wells MW-2 and MW-3 to 0.77 in MW-1 but decreased by 0.35 feet in monitoring well MW-8. The apparent groundwater flow direction in the lower aquifer was generally easterly to southeasterly at a gradient of approximately 0.003 (Figure 4). As part of the construction activities for widening West Hammer Lane, the casing of MW-8 was cut and the well box lowered by V&W Drilling on August 11, 2000. The monitoring well was resurveyed by Morrow Surveying on May 22, 2001. The report is presented in Appendix D. The groundwater elevation for MW-8 this quarter and the previous quarter are presented in Table 1. Laboratory analysis of the water samples collected on May 22, 2001 indicate that TPH-G, BTEX, and MTBE were not detected in groundwater samples collected from MW-3 and MW4 in the local lower aquifer. Low concentrations of TPH-G and BTEX were detected in the off-site well MW-8 for the first time since this well was first monitored on December 9, 1999. In the local upper aquifer, TPH-G, BTEX, and MTBE were not detected in groundwater samples collected from MW-6 and MW-7. TPH-G was detected in groundwater samples collected from MW-1R and MW-2 in the lower aquifer and MW-5 in the upper aquifer. BTEX was not detected in any of the well samples with the exception of low concentrations of BTEX in MW-8. Analytical results of fuel oxygenate compounds by USEPA Method 8260 indicate that MTBE was detected in the groundwater samples obtained from monitoring wells MW-1R at a t 20M Fourth Quarter Omwdw tra Monilodng Report i J:%1n Pr09-1QLaXS MPQS 13ZREPORZSS200 I ti2ndQtM i rpt dm