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s�. a. I !i {I! ' err r n p.mn' ' f ,F•- _ ',;�{ i d-� 14 h it I'" !I _ - I I t I L,;I �. :I ' •{ -II ' 14 r'•f f Iad.TS IL s I V ' 'Y It I I•!I.1. , ' ,i •h � I-,. '�N� i �1 ps, N F F s �I'{' i, I •S•I I' .I�' k I ! Y ' ; I 21yApnl 2003 ' {. y. AGE-NC Project No: 95-01114 r U1 R rPag. 2 Of 5;1, 2.2. COLLECTION AND ANALYSIS OF GROUND'WATER SAMPLES Ground water'samples.were collected from.the purged wells using new.disposable bailers following " recovery of at least 80% of the pre-purge casing water voluriiem . Imediately upon retrieval, the samples were transferred into 40-m1 EPA-approved volatile organic analysis(VOA)vials containing 0.5 ml ofhydrochlonc acid(18%)as a sample preservative, and were properly-labeled.The samples .' . , were transportcd.,irl, a' chilled' cantairier under chain-of-custody' to Cal Tech Environmental,A • : . • ' .:. Laboratories, Inc (CTEL), a.State'of California Department of Health Services (DHS) certified • laboratory=iri Paramount, California: The samples were anal yzed for•: Volatile organic compounds (VOCs); specifically benzene, toluene, ethylbenzene and xylenes' (BTEX) ,and 'the fuel'additives ethylene dibromide (EDB) 1,2-dichloroethane (1,2-DCA),icrtiarybutanol(TBA),,di-isopropyl ether(DIPE),ethyl"tert butyl,ether(ETBE), r ", tert'amyl,methyl'ether (TAME), and methyl tertiary butyl ether (MTBE) by EPA Method . ' 8260B; and" Total, etroieum hydrocarbons quantified as Stoddard solvents (T-PH-ss) by EPA Method . p , 8015 Modified. 3.0. FINDINGS i Ground water flow direction and gradient were inferred from the fieid'data.The current distribution of dissolved petroleum hydrocarbons'and dissolved chlorinated hydrocarbons was assessed from, " t laboratoryanalytical results of the soil and ground water sam les. ., Yt � P. . . . .- 3.1. GROUND WATER GRADIENT AND DIRECTION U . During the January 2003 groundwater monitoring event,the depth to.ground,water at the site ranged 'from 24.89 to 26.41 feet below the tops of the well casings.The ground water elevation ranged from 16.39 to'.17.18 feet below mean sea level'(MSL). The ground water flow direction was toward the ; northeast from well MW-5 toward well MW-10,with a gradient of approximately'0.0019 feet/feet. Ground water elevation data are summarized in Table 1'.The contoured ground-water,elevation for the ground watermonitoring event is depictedin Figure.3. .Wells MW-1 through MW-5 were screened between 30-or 34 and 50 feet bsg;wells MW-6 through'' MW-10 were screened between 20 or 25 and 45 or'50 feet bsg: The ground water level was more ' than,10 feet above the tops of the screened intervals of wells MW-1 and MW-2,almost 6 feet above thetops of the screened intervals ofwells MW-3R,MW-4 and MW_51 and at the tops of the, ,• ; IM - • Advanced GmEnoir n eaffilf Inc.