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19 July 2000 . AGE-NC Project No 96-0232 Page 8 of 29 • in Second Zone Upper q Rocky's U er Zone and Second Aquifer Zone samples from boring P16 at concentrations from as high as 280 µg/1 in Second Zone to as low as 6 µg/1 in Secondary Aquifer Zone in samples P16-53 to 56 and P16-87 to 90 TBA was detected in Second Zone sample P16-37 to 40 at a concentration of 6 µg/1 Ethanol was detected in four samples collected from P17 Ethanol was detected as high as 27 µg/l from sample P17-80 to 83 (Secondary Aquifer Zone) Ethanol was detected as deep as Primary Aquifer Zone at a concentration of 20 µgll in P17 MTBE was detected in Second Zone sample P17-55 to 58 at a concentration of 150µg/1 MTBE was detected at depths of the Secondary Aquifer Zone in sample P17-80 to 83 at a concentration of 4 9 ,ug/1 TBA was detected in sample P17-111 to 114 (Primary Aquifer Zone) at a concentration of 7 1 µg/l Analytical results of ground water samples are summarized in Table 6 The laboratory reports and chain-of-custody forms are presented in Appendix D 5.0 INSTALLATION OF MULTI-LEVEL MONITORING WELLS iOn 02 through 10 May 2000, multi-level monitoring wells MW-8 through MW-13 were installed by West-Hazmat Drilling Corp Monitoring well MW-8 was installed approximately between 40 to • 50 feet northeast of ground water monitoring well MW-4 to characterize lithology, ground water gradient, potential contaminant migration pathways and to assess the vertical extent of MTBE-impacted ground water north of the former UST system The location of multi-level well MW-8 is illustrated in Figure 2 A generalized design of multi-level monitoring well MW-8 is presented in Figure 17 Based on laboratory results of soil and ground water samples and field data collected from on- and off-site, multi-level monitoring well MW-8 was designed utilizing three separate screen intervals, 40-60 feet bsg (Second Zone), 95-105 feet bsg (Secondary Aquifer Zone), and 130-150 feet bsg (Primary Aquifer Zone) The First Zone was already covered in the area by MW-4 On 03 May 2000, West-Hazmat Drilling Corp attempted to install multi-level monitoring well MW-9 Installation of MW-9 was unsuccessful due to lithologic conditions The pilot boring was properly destroyed by backfilling from total depth to surface grade with portland cement On 04 May 2000, monitoring well MW-9 was re-installed approximately 3 feet away from the original location, near the southwest corner of the property, to characterize lithology, ground water gradient, potential contaminant migration pathways and to assess the vertical extent of MTBE-impacted ground water west of the former UST system The location of multi-level well . MW-9 is illustrated in Figure 2 A generalized design of multi-level monitoring well MW-9 is presented in Figure 18 Advanced GcoEmironmental,Inc