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2.5 Additional Soil and Groundwater Imestiigation ' Seven ground1water monitoring wells had previozzly been installed on or near the site The wells were insdalled to depths of 55 feet At the 6nie of installation, groundwater depth was approximately 42 feet Subsequently,groundwate'rdepth fell below 55 feet and all "e Ils mere dry. On June 13 atad 14, 1994, four soil borings w ere drilled at the site Borings MW-8 and MW- 9 were advanced to depths of 75 feet and completed as groundwater monitoring wells Borings CB-1 and CB-2 were advanced to a depth of 65 feet and backfilled with Portland cement Hydrocarbon odors were noted in samples frorrm boring CB-1 at depths from 20 feet to 45 feet and in baring CB-2 at depths from 35 feet to 45 feet Oiganic vapors were detected by the PID at concentrations up to 564 ppm (CB2-35) No hydrocarbon odors or organic vapors were detected in borings MW-8 or MW-9 no pelroleurn hydrocarbons %Here detected in the samples analyzed from MW-8 or MW-9 I Petroleum hydrocarbons were detected in bonne CB-1 at depths of 20 feet and 35 feet and in boring CB-2 at depths from 30 feet to 40 fejt No benzene was detected in any of the samples analyzed T�,tio soil samples were also analyzed for total lead Lead was detected in samples C131-15 and CBI-20 at concentrations of 12 ppm and 9 ppm, respectively On June 16, 1994, quaiteily gioundx%atej monitoying was Iesunied at the site The depth-to- water was measured in NNW-S, 111W-9 and EW-3 and the ��ells N%eie purged and sampled Groundwater oiadient was calculated to be 0 0024 ft/ft diiected N SO' E Toluene and xylenes were detected in the sample: fioni %IW-9 at concentiations of 0 52 ppb and 2 9 ppb respectively No other petroleum hydiocaibons %%ere detected in any of the samples Groundwater at the site dropped an avei age of 2_07 feet betmeen June and September 1994 and then rose an average of 0 25 feet bets een September and October 1994 Groundwater ' gradient was calculated to be 0 0004S ft/ft directed due south during the September monitoring T1re giadrent during the October irmnitoiing «as calculated to be 0 0013 ft/ft directed N 56° E The September giadrent is significant]), more shallow than previous ' monitorings, and represents a 100 degree change in flow direction The October monitoring shows a ieturin to previous flow direction and gradient No petroleum hydrocarbons «tele detected in any of the samples collected during -lie September 1994 monrtoirng 3.0 PROCEDURES 3.1 Monitoring g Well Pur a Procedures On December, 12, 1994, groundwater depths in monitoring wells MVV-8, MW-9 and EW-1 1 13-6s-IAu4t k—enoa 1- 5 Ga-w ey QA7A2 9411 l