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<br /> »�r9��20.November-1998 3 ' , , ' •,,' , ; 4 ,? t , .� 4 y t,j ` .,: y , ,F }' r l4'A'.''r.
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<br /> ojedtNo. 95-0124 -
<br /> ,F -AGE NC.,Pr
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<br /> S G NI F - ,. .1 f I. I i' ' ' i 1�•''.
<br /> 12.2 �LOLL-ECTION`OF.GROUND�WATER SAMPLES
<br /> I f
<br /> Dunn .both sampling events
<br /> g p g. ground water samples were:collected `from each'' well:using,new
<br /> ii disposable baileis. Ground water samples were'collected directly nfollowing the purging of each well
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<br /> in an attempt to sample while the'recharge water was within the screened interval of the moriitoring7
<br /> we-,
<br /> ` r .s I1S. _I .I r- , .. . - '. r'' •' ', t r' t i i l ,
<br /> 4mrnediately;upon retneval,,the samples were transferred into 40=rill'EPA=approved"VOA'vials;' r
<br /> # containing 0S In of hydrochloric acid,(18%)'as a.sample preservative,' and'were-`labeled: The '
<br /> ' samples were transported iri a chilled'containerunder:chain:Of-custody.to McCampbell Analytjcal, ,
<br /> -Inc.,-(IvIAI)a state-certified laboratory�in.Pacheco,California. Samples were,analyzed iri accordance'
<br /> i i � with •' ' . - ; . . , _.,.V�. -• ,,; ',f•:
<br /> Ia
<br /> EPA,Method,801.541 for total petroleum hydrocarbons quantified as Stoddard solvents(TPH-.' r
<br /> ^ `ss),° j i
<br /> EPA Method 8020 for volatile aromatics x '
<br /> (benzene;toluene, ethylbenzene and total xylenes:
<br /> BTEX) and
<br /> • EP,A.Method'8010•for volatile halocarbons (chloririated.hydrocarbons):
<br /> 3.U. FINDINGS
<br /> 3:1. .GROILND'WATER GRADIENT AND DIRECTION
<br /> The groundwater elevations were calculated by subtracting the measured depth to groundwater
<br /> from the•surveyed casing elevations{Table l). Ground water'elevations were plotted:and"contoured tr
<br /> on a scaled site•map:
<br /> The average relative ground water elevaiion'at the site increased approximately 4.5 feet between the
<br /> 4'
<br /> •December 1'997-and ihe.March I998-sampiingevents:During the March 1998 sampling,,theldepth
<br /> . ,
<br /> to ground water at the site' 'ranged from 23.17 to 24:41 feet beiow,tops of ihe'.we11 casings.. aY '
<br /> During the July 1998 said liri the depth to-ground water at the site ran ed from 21'.681to 22:39 feet
<br /> P g, g
<br /> below cops ofae well casings: The average-relative.ground-water elevation"at the site increased
<br /> approximately 1.6 feet since the the March and Jul •19
<br /> = Y. 98 sampling event
<br /> a r 1, .hq . . , r -• _' • '• '. "" �::: •-- .' . ',; '', .• ? , .. '.+ r.i' ��,
<br /> Theacreened intervals in wells MW-f and MW-2 lie between 34 and 54 feet bsg, and the.screened
<br /> intervals in wells MW-3R,MW-4 and MW75 lie between 0-and SO feet bsg,`thus,groundwater is 3 ;.
<br /> �F r I Ar Yanmd.GeoEavirorimenial,In G
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