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I
<br /> 11�.rman& ]ie,lLn 4 Maruta - Scumd QutrtLr 1998 Groundwater Monuonng
<br /> Augu%t 11 1998
<br /> IPage 7
<br /> groundwater Samples collected froin the nortilLm portion of tilt. %1tc and that further in1Vest1gatlon was necessary
<br /> to evaluate the extent of soil and groundwater contanimation
<br /> IBased on the results of the Gcoprobe investigation, ( ondor rCLOrnmended that monitor wells be installed at the
<br /> site to 11lvc5t1pate and monitor the lateral extent of the gasoline and dlc,scl eontarnmation plume In the
<br /> groundwater On 1�eptembcr 10, 1997 Condor m5talled lour monitor wells at the site file Repoit - 4cldaional
<br /> '5011 cruel Ojowitliialei hnc%figalton dated Uccembcr 1 1, 1997, vrati prepared by ( ondor to describe the
<br /> lrivc,tigaticin results
<br /> I PfI-G, 13 rrx constituclits, M 1131- tertiary butanol and tertiary amyl methyl ether ( FAME) were detected in
<br /> tiomc. of the boil and groundwater san{ple5 collected during the, investigation Groundwater cicvation data
<br /> indicated that groundwater flow at the site was probably controlled by the very aetive island drainage pumping
<br /> system adjacent to the, site Ilie above, retcrenced report recommended quarterly groundwater monitoring,
<br /> surfact water sampling and Rist. Based C Orrcctive Action (RBC'A) to further characterize the trite and to
<br /> evaluate, options for rt.medlation or site closure
<br /> In a telephune conversation on March 23, 1998, Mr Ronald Rowe of the. San Joaquin County Public IIealth
<br /> Services/Liivironmental Health Department (PHS/FHD) indicated that based on his review of the report dated
<br /> December It, 1997 (referenced above), he was requesting that quarterly groundwater monitoring continue at the
<br /> site I-urthermore, he requested that a work plan be prepared for cmnduaing quarterly surface water sampling
<br /> i and additional mvc stigation of the gasoline oxygcnateladditive plume to the cast of monitor well MW-2 Condor
<br /> subsequently prepared the 1Voik Plan Additionul Sod unci (,i undivulei lnievtrgution / .Swfuce [Vuler
<br /> Sumphnir dated May 27, 1998 In a faxed note dated June 1, 1998, Mr Rowe approved the work plan with the
<br /> stipulation that a work plan addendum be prepared describing installation of additional borings to those proposed
<br /> in the work plan and grab Sampling of the. 11crman & Ilclen's Marina drinking water source Condor
<br /> subsequently prepared the 111ork Plan 4dtlend nn, dated July 9, 1998 In a tax dated July 27, 1998, Mr Ron
<br /> Rowc approved the %Mork plan addendum adding that both the facility pre-treated drinking water and the post-
<br /> treatment water should be sampled and analyzed by appropriate methods A comprehensive site background is
<br /> included in Appendix B
<br /> r3 SECOND (QUARTER, 1998, GROUNDWATER MONITORING
<br /> 3.1 FIELD METHODOLOGY
<br /> On June 26, 1998, Condor personnel were on site to conduct quarterly groundwater monitoring activities The
<br /> monitoring activities included measurement of water levels in the site monitor wells and at surface water
<br /> measurement stations and the collection of groundwater samples from the monitor wells All field equipment
<br /> I was decontaminated in the field with a solution of laboratory-grade, non-phosphate detergent and hydrocarbon-
<br /> free water and rinsed with hydrocarbon-free water prior to use in each well All field instruments were calibrated
<br /> to the manufacturer's recommended standards The water level in each well was measured to the nearest 0 01
<br /> foot with a battery-operated, flat-tape, water-level meter A new, disposable, polyethylene bailer was lowered
<br /> into each well to collect a field-inspection sample The bailer sample was inspected for floating product, sheen,
<br /> discoloration and/or odor Floating product was not observed in any of the monitor wells during the groundwater
<br /> sampling! A slight petroleum hydrocarbon odor was noted in the groundwater sample collected from monitor
<br /> well MW-2
<br /> The purging and sampling sequence for the monitor wells was MW-1, MW-3, MW-2, and MW-4 The wells
<br /> were purged with a C,rundfos Readiflo II submersible pump For the purpose of evaluating intrinsic
<br /> bioremediation, various parameters were monitored during the purging of each well, including dissolved oxygen,
<br /> reduction-oxidation potential, pH, electrical conductivity, and temperature I he purge water was discharged to
<br /> %&I 0_0�'
<br /> t� CONDOR
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