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Addtkianal Soil and Groundwater investtgatton Report Canepa's Cas W aahjuly 12 2004 Page 8 SULTS April 13, 2.004 S 4 SUMM��DISCUSSI�N OF RE tiese the subsurface soil lithology nal soil and groundwater investigation actIv Lenz t the site from es Condor conducted addltio through April 19, 2004 The Li ose of the work was to furtherextents hydrocarbon ear of the site by CPT rtiethods, to further investigate the e�rtog hydrocaabonlconiam nation m soil five contamination in �oundwater, and to define the vertical ext both on-and off-site, and the installation red at the site The investigation activities included the installation the presumed source a airs (CPT3 through CpT7), les ranging in $epth from additional CPT near boring p to collect soil same of one soil boring ($2) near the former UST's to attempt approximately 82 5 to 115 5 feet bgs s from this and the S011 behavior type classification tog relatively Based on the results of the seven CPT boxing al, there appears to be a anon, the soils beneath and to the nartmaon�t s� re dominated y s P CPT irtvesttg with a variable sand co p and sandy/silty, horizons, heterogeneous mixtures of silt and clay aver-age between the depths of slight increase in the sand component from west to east across the Site Sandy to 1_50 Bich appear et 74 to 85 feet, 102 and 125 feet, and timpede ede thef vertical eet w P ear to be relatively laterally extensive across the site, occur on 26 to 35 feet, 52 to 60 ° which would be expecte approximately rich horizons, occur on average between approximately 35 to 45 feet, 60 to 70 feet, 8 to Significant laterally extensive clay- migration of contaminants, 100 feet, and 127 to 137 feet approximately 46 feet bgs in 1984 when mitral monitoring 23 feet bgs Since 2000, the water levels have declined to Historic groundwater levels steadily rose from app MW3 are screened from began,to peak levels in 2Q00 at approximately wells MWthrough through roxirriately 27 feet bgs Monitoring h MW7 are screened from present levels at app and monitoring wells MW4 ttuoug 45 – 65 feet bgs s have approximately s The taps of screen intervals in all oh�� first relatively gyey horizon approximately 40 – 60 feet bgs wells are screened throng trration of contaminants m been submerged since 1995 would The monitoring oring well to impede the vertical rn" 35 to 45 feet bgs) the underlying relatively sandy horizon and well into the second ( oundwater, and in some cases, through relatively clayey horizon alts of Che two soil samples collected Boring B2 soil samples were collected from saturated horizons well below the current water table near analytical re est sample present in the deep the presumed contaminant source rr leuin li drocarbon constituents are p Y Te near from boring B2 indicate that P However, contaminant concentrations at that depth boring from 105 ■ collected (approximately 97 5 feet bgs) le collected from the CpT7 hydrop similar to the oundwater camp very method detection limits The gr hydrocarbon constituent concentrations etr°leum Y suggesting that the contaminants in the soil to 109 feet contained p le at 97 5 feet bgs, concentrations detected in the soil sarnPle at 97 Ser component rather than residual contaminants in the sample were dissolved nant concentrations one to two til the sa $2 at SZ 5 feet b onto, e �o arni tle�ollected between 75 and 80 et soil The otl sarnple ollected oundwater camp ed in CpT7 souridtn9 at nude greater than the corresp°ndin horizon logg 6V_ � orders of mage suggesting t a t e c ay bgs in the.��ydropunch boring, eding the vertical migrath°n of contaminants in 5ot1 an ificantly imp B2 Based on approximately 87 feet bgs is sign to he TBE was not detected in either of the soil samples collected from boring groundwater M these results, further Investigation of the vertical extent of soli contamination does not appear necessary les Indicate that relatively elevated dro unch groundwater same The laboratory analytical results of the by p constituents are present at depths well belor first encountered group wa er gasoline co + concentrations of CONDOR AM f %41? — -