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l I1 Z 111 d Interim Remediation Plan and Second Quarter 2001 Groundwater Monitoring Report a, Moore Petroleum Bulk Plant,5491 F Street,Banta,California Page 5 On March 27, 2001, a round of groundwater levels was collected manually from recovery well RW-2 and monitoring wells MW-3,MW-8, MW-9, and MW-12 before the test began. The transducers were turned on at 10:00 AM and the pumping test initiated at 10:15 PM. The pressure transducers recorded water levels at 5-minute intervals. Additional groundwater levels were collected manually from recovery well RW-2. The pump operated for 48-hours during the test. The pressure transducers continued to collect data for approximately 90-minutes after the pump was turned off. i' All manual groundwater elevations were measured to the nearest 0.01 foot, referenced to the surveyed top-of-casing elevations, and performed according to the Apex Standard Operating Procedures (SOP) included as Appendix B. Groundwater level measurements collected manually from recovery well RW-2 during the pumping test are summarized in Table 1. Manual groundwater elevations collected from the monitoring well containing the pressure transducers were calibrated into the pressure transducer data to reflect actual groundwater elevations. Groundwater elevation data from the data loggers are presented in graphical and tabular format in t Appendix C. A complete round (with the exception of well MW-6) of groundwater levels was also collected on March 29, 2001 at 9:00 AM to determine the hydrologic control imposed by '. dewatering the former tank basin area during the pumping test (Table 2). Groundwater SamylinjZ and Analysis E Apex personnel collected groundwater samples from recovery well RW-2 at 1:15 PM on March 27, 2001 and at 10:00 AM on March 29, 2001 at the conclusion of the test. The samples were submitted, under chain-of=custody,to CLS Labs of Rancho Cordova, California, a state-certified analytical laboratory. All samples were collected according to the Apex SOP. Analytical results are for TPHg, and as diesel (THPd); benzene,toluene, ethylbenzen:e, and total xylenes:(BTEX) by EPA Method 8020; and di-isopropyl ether(DIPE), ethyl tertiary butyl ether(ETBE), methyl- tert-butyl ether(MTBE), tertiary amyl methyl ether(TAME), and tertiary butyl alcohol (TBA), collectively the `five oxygenates' by EPA Method 8260 are summarized in Table 3. The # laboratory analytical reports and chain-of-custody forms are'included as Appendix D. ;All detected constituents have been converted into pounds removed based on the analytical results and the volume of groundwater removed during the pumping test. The total pounds of gasoline 1' constituents removed during the pumping test are summarized in Table 4. 1 Pumping Test Results t � Figure 3 is a groundwater contour map of the shallow water=bearing zone on April 5, 2001 under static conditions. Based on the Figure 3 potentiometric surface map, groundwater beneath the site flows in a northeasterly direction at an approximate hydraulic'gradient of 0.0075 ft/ft under natural conditions. Figure 4 illustrates the potentiometric surface under pumping conditions 1 collected during the final minutes of the 48-hour pumping test. As shown on Figure 4, I. groundwater flow near well MW-12 was not influenced during the pumping test. 3