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On March 16, 2000, SJCEHD requested that the vertical and lateral extent of the
<br /> documented contamination be further evaluated, and additional monitor wells be installed.
<br /> JJW submitted a workplan and a workplan addendum on May 12, 2000, and July 31, 2000, in
<br /> L- response to the SJCEHD directive. The workplan outlined the additional site assessment,
<br /> monitor well installation, and replacement of the compromised monitor well MW-7 required by
<br /> SJCEHD. SJCEHD approved the workplan on August 30, 2000.
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<br /> JJW completed direct push water sampling and analysis on April 6, 2001 to evaluate the site
<br /> for monitor well placement.
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<br /> On May 2, 3, and 4, 2001, a soil boring with interval water sampling (SB2), and four additional
<br /> monitoring wells (MW-9 to MW-12) were installed. MW-7 was abandoned and replaced by
<br /> ` MW-7A.
<br /> Monitor well MW-3 was damaged in 2002 due to construction activities at the adjoining
<br /> business and could no longer be sampled. After approval from SJCEHD, MW-3 was abandoned by overdrilling and grouting with cement from the bottom, using tremie pipe, to
<br /> the surface on October 8, 2004.
<br /> �- In September and October, 2004, twenty sparge points, ranging in depth from 37 feet bgs to
<br /> 130 feet bgs, were installed at twelve locations in and around the petroleum hydrocarbon
<br /> contamination plume. In November and December, 2004, the sparge points were plumbed to
<br /> �.. an ozone generating system installed at the subject site. Ozone sparging was initiated on
<br /> December 1, 2004.
<br /> ,., The SJCEHD recommended, in a letter dated March 18, 2008, modifying the sampling
<br /> regimen of groundwater monitoring wells MW-4, MW-6, MW-9, MW-10, and MW-12 to
<br /> annual sampling events from the current quarterly sampling schedule, and on March 9, 2009
<br /> changing the remaining wells to a semi-annual sampling schedule.
<br /> 3.0 SEMI-ANNUAL GROUNDWATER MONITORING
<br /> 3.1 Groundwater Sampling Activities
<br /> JJW Geosciences, Inc. (JJW) conducted groundwater monitoring and sampling activities on
<br /> June 23, 2009. All eleven groundwater monitor wells were sampled for this event. The five
<br /> monitoring wells on the annual sampling schedule were last sampled the during the second
<br /> +- quarter, 2008, sampling event. Prior to purging, and sampling the monitor wells, JJW
<br /> measured and recorded the depth to static groundwater in all eleven groundwater monitor
<br /> wells. We present current groundwater depths, and groundwater gradient and flow directions
<br /> �. in Table I and on figure 3.
<br /> Following water depth measurements, we utilized a Grundfos pump and a 12 volt DC pump
<br /> �. to purge the groundwater monitoring wells until at least two or more of the readings for
<br /> temperature, pH, conductivity, and oxidation-reduction potential (ORP) approximately
<br /> stabilized or three well volumes were purged or the wells were completely dewatered. The
<br /> purged water was placed in 55-gallon drums and stored on site awaiting future disposal at an
<br /> approved facility. The Grundfos and DC pumps were decontaminated by washing in Alconox
<br /> solution and rinsed in potable water, between each use.
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<br /> L. 2 JJW GEOSCIENCES Inc.
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