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<br /> QlJARTERLY GROUNDWATER MONITORING REPORT
<br /> FOURTH QUARTER, 1998
<br /> Herman & Helen's Marina
<br /> Venice island Ferry
<br /> Stockton, CA
<br /> February 7, 1999
<br />' 1 INTRODIK"7 ION
<br /> On December 30, 1998, ( ondor Larth I echnoIOgle',, Ire (C ondor) conducted quarterly groundwater and surface,
<br /> water monitoring at Herman Rc Helen's Marina located at Venice Island Ferry in Stockton, California (Figures 1
<br /> and 2, Appendix A) I hc, work described in this report was conducted in accordance with sampling procedures
<br /> included in [folk Plan - Alonttor We// Installation and Work Plan Iddendum, prepared by Condor and dated
<br /> I May 30, 1997, and July 9, 1998, respectixely the work plan "as conditionally approved by Mr Ronald Rowe
<br /> of the San Joaquin County Public I lealth Sen ices/Lnvlronmc,ntal l lealth Department (PHS/F'HD) in
<br /> correspondence dated July 8, 1997 The, work plan addendum was approved by Mr Rowe in correspondence
<br /> dated July 27, 1998 1 he fourth quarter, 1998, monitoring described in this report is the fifth quarterly
<br /> groundwater monitoring event and the second surface water sampling event to be conducted at the site This
<br /> report was prepared at the request of Mr David Smith of Herman & Helen's Marina
<br /> Laboratory analytic.~ of the groundwater and surface water samp[cs included benzene, toluene, ethyl benzene and
<br /> total xylenes (BTI-X), total petroleum hydrocarbons quantified as gasohnc (FPI1-6), and ,elected gasoline
<br /> oxygenatesladditivLs Phis report includes a ,Etc. history, a summary of the current monitoring event (including a
<br /> description of the trampling and laboratory analytical results), and summary/conclusions
<br /> 2 SITE, BACKGROUND
<br /> On October 30, 1991, Wai ren I Gomes Excavating, Inc , of Rio Vista, C aliforma, excavated and removed three
<br /> underground storage tanks (USTs) from the site (Figure 2, Appendix A) The USTs (TK I, `1 K2, and TK3)
<br /> contained gasoline and diesel fuel A small hole Aas found on the lower fill end of TK3 (diesel tank) Petroleum
<br /> staining and odors were noted in the soil beneath the former locations of the USTs Six soil samples were
<br /> collected by Condor from the t1ST excavation at depths of 9 to 12 feet below the ground surface Laboratory
<br /> analyses indicated elevated concentrations of "I PH-G, BTEX, and total extractable petroleum hydrocarbons
<br /> quantified as diesel (TEPII) in the soil samples
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<br /> On August 22, 1995, three hydropunch borings were drilled at the site Gasoline odors were noted in each
<br /> borehole Laboratory analyses indicated concentrations of TPI1-G and BTEX in the soil and groundwater
<br /> samples analyzed from each borehole Based on the results of the August 1995, investigation, Condor
<br /> recommended additional investigation be conducted to evaluate the extent of the hydrocarbon plume On August
<br /> 29, 1996, five Geoprobe boreholes were installed at the site The results of the laboratory analyses indicated that
<br /> elevated concentrations of TPH-G, B7 EX, and methyl tertiary butyl ether (MTBE) were present in soil and
<br /> groundwater samples collected from the northern portion of the site and that further investigation was necessary
<br /> to evaluate the extent of soil and groundwater contamination
<br /> Based on the results of the Geoprobe investigation, Condor recommended that monitor wells be installed at the
<br />' site to investigate and monitor the lateral extent of the gasoline and diesel contamination plume in the
<br /> groundwater On September 10, 1997, Condor installed four monitor wells at the site The Report - Additional
<br /> Sod and Oroundwater Invevhgation, dated December ll, 1997, was prepared by Condor to describe the
<br /> investigation results
<br /> �, CONDOR
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