ARCHIVED REPORTS_XR0005656 - Laserfiche WebLink

Home Browse Search

Mr Jeff Wong Page 2 of 4 MW 1 since August 16, 2001 Attachment A contains copies of field logs related to product monitoring and removal 2.2 Liquid Waste Disposal American Valley Waste Oil removed and transported approximately 370 gallons of purged groundwater that was previously removed from site wells and temporarily stored on site In addition, approximately 130 gallons of product/water mixture that was removed from well MW1 was also transported off-site for disposal Attachment B contains copies of the waste manifest and load tickets that document liquid waste disposal 2.3 Groundwater Monitoring and Sampling A Ground Zero technician monitored water levels in all site wells and collected samples from monitoring wells MW2 through MW913 on December 11 and 12, 2002 No sample was collected from well MW1 due to the presence of free product Groundwater elevations were calculated by measuring the depth to groundwater in each well and subtracting the measured depth from the respective well head elevation The measured depth to groundwater below the tops of the well casings (btoc) ranged from 64 10 feet in well MW1 to 65 O1 feet in well MW5 (completed at approximately 2 25 feet above ground • surface) Groundwater elevations at the site ranged from 32 23 feet (MW2) to 32 57 feet (MW9B) below mean sea level Groundwater Ievels in shallow monitoring wells MW1 through MW8 rose an average of 0 73 feet between September 12, 2002 and December 11, 2002 The groundwater level in well MW913, which was completed in a deeper aquifer, rose 0 91 feet during the same period Table 2 summarizes groundwater elevations in site monitoring wells Shallow groundwater beneath the site generally flowed to the north-northeast on December 11, 2002, although an apparent groundwater depression was present in near well MW3 The average groundwater gradient south of well MW3 was 0 003 (approximately 16 feet per mile) Figure 2 presents a potentiometric surface map generated using the December 11, 2002 monitoring data An experienced Ground Zero technician purged at least three well casing volumes of water from monitoring wells MW2 through MW9B prior to sampling the wells The technician measured the water's temperature, pH and electrical conductivity during the purging process and collected samples after the physical parameters stabilized and water levels in the wells recovered to at least 80% of their pre-purged levels Purged groundwater was contained in appropriately labeled DOT-approved 55-gallon drums in accordance with 49 CFR part 172 and 40 CFR part 262 Groundwater samples collected from the monitoring wells were delivered under chain of custody protocol to Argon Laboratories (ELAP #2359) for analysis Attachment C contains copies of field data sheets and purge logs for December 11 and 12, 2002 G NDataIGROUNDZEITULEBLTRG1Rcports\QMRWQM2002 doc