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Working To Restore Nature 3.1.1 Work Description ' Monitoring wells MW-1, VW-1, VW-2s, vW-2d, VW-4, VW-5s, VW-5d, and PZ-1 were used during the VET. Wells VW-2s and VW-5s are screened from a depth of about 10 feet bsg to maximum depths at or less than 30 feet below grade. Wells MW-1, VW-1, VW-2d and PZ-1 are screened in depth intervals of 35 to 55 feet bsg, 15 to 30 feet bsg, 34 to 41 feet bsg, and 40 to 60 feet bsg, respectively. The wellhead vacuum, air velocity, organic vapor concentration, temperature, and observed vacuum influence of the observation wells were measured and recorded every 15 or 30 minutes ' during the tests The distances between the extraction wells and the observation wells are listed in Table 2B, Vapor Extraction Test Monitoring Data, January 18, 1994 Influent vapor samples were collected at 1-hour intervals. An effluent vapor sample was also collected to estimate the efficiency of the I C engine i� The vapor samples were analyzed at Sequoia Analytical Inc. in Sacramento, California (Hazardous Waste Testing Laboratory Certificate No 1624), for benzene, toluene, ethylbenzene, ' and total xylene isomers by modified Environmental Protection Agency (EPA) Method 8020 and for total petroleum hydrocarbons reported as gasoline(TPHg)using modified EPA Method 8015. RESNA followed chain-of-custody protocol throughout field and laboratory procedures. Copies of the Chain of Custody Records and results of laboratory analyses of the vapor samples are ' attached The results of laboratory analyses for the vapor samples are summarized in Table 2 ' 3.1.2 Results ' The VET conducted on vapor extraction well VW-1 had an applied vacuum ranging from 17 to 2.7 inches of water (inches H20), and air flow rates ranging from approximately 52 to 87 ' actual cubic feet per minute (acfm) Response vacuums were recorded for each of the 38009-8138009-8 FRP 6 1