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r r1.• 1 - r 4 11 ; ,1 '. } 1 f SP1 T !x `!� `.f I . 40 Dec' bdr 2`001 • ''' �' AGE NC Project No 12 COLLECTION,OFJGROUND WATER-SAMPLES Ground water;sainples were:collected from each well`using new:disposabie bailers `Gr`oun water: samples`wer�collected following-the purging ofA e wells,and recovery ofaat least 80%0 of the pre- 4 purge casing water,volume •Immediately,upon retrieval, the:samples were, ransferred into 40-m1' EPA=approved-VOALvials,contaning 0:5 ml ofhydrochloricacid.(18%) as a sample preservative; t' ,and were,labeled.'The;samp leg.were transported in'a chilled corifainer under chain=of-cusfody to IcCampbell Analytical.Inc.'(VICAI)•a State'of California Department of Health Services(DHS) certified'laboratory(#1644):'Samples-were arialyzed for: Total- etroleum li drocarbons,.' uantified as; asoline and'stoddard`solvents (TPH-g/ss) by, EPA,Method,801'5 Modified; - Volatile aromatic,'compoW ds -'benzene,"toluene, ethylbenzene and xylene (BTEX) with methyl tertiary.butyl ether(MTBE)by EPA Method 8020; and" „Volatile organic compounds(VOCs) -'specifically fuel additives methanol;ethanol;ethylene ' dibromide (EDB), 1,2-dichloxoethane{1,2-DCA),' tertiary butanol (TBA);di-isopropyl ether '(DIPE); ethyl tert butyl gther (ETRE); tent amyl'methyl ether (TAME), and.confirmation of I. MTBE by.EPA Method 8.260.Modifled. ' 3.0. FINDINGS , '. Ground water-flow direction. and .gradient. were calculated from the 'field data.` The,current` r distribution of dissolved petroleum, hydrocarbons and dissolved'chlormated hydrocarbons.,was, assessed from laboratory analytical reslilts!`of the,soil,and ground water samples. GROUND WATER GRADIENT AND DIRECTION _ 1 ';The,ground water elevations'were calculated:by subtracting the measured depth to ground water frain thesurveyed,casing elevations,.(Table.i):-Groundwater elevations werc'plotted and'contoured on- ' a scaled site map. During the October 2001 ground-water monitoring event,-the depth to groundwater at the•.site''ranged' 24" to.25.45 •feet below tops of, well casings. The groul.nd water gradient`.and_flow direction•wds northeast across the.siteAunng the October 2001 monitoring event.Ground water flow. { drrection`vaned from northwest to northeast,the greatest gradient was approximately 0.002'generahy 'f ' xtoward'the.riorthwest'-frorn' well IVMW-.1; toward .well N4W.-6. Ground ivate'r``elevationfldata'`are "I, 4dvanced GeuEnvironsnental,[nc.