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(ZLIARTF RI,Y GROUNDWATER MONITORING, REPORT
<br /> SECOND QUARTER, 1999
<br /> Herman & Helen's Marina
<br /> Venice Island Ferry
<br /> Stockton,('A
<br /> August 20, 1999
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<br /> 1 INTRODU( TION
<br /> On JunL 30, 1999 ( ondor I arth I LL hnologies Inc (( ondor) conducted quarterly groundwater and surface water
<br /> monitoring at Herman & Helen's Marina located at Venlee island I-crry in Stockton, Californma (figures I and 2,
<br /> Appendix A) 1 ht «ork described in this report N4as conducted in aeeordancc, with sampling procedures included
<br /> in the. If 01-k 1'1u11 - 110111101- 1'Vail M%fallalion and the II'm k Plug Ackle1ulum, prepared by C ondor and dated May
<br /> 30, 1997, and July 9 1998, respectively The N4ork plan Naas conditionally approved by Mr Ronald Rowe of the
<br /> San Joaquin C ounty Public Health SLrvices/EnN,uonmental Health Department (PHS/EHD) in correspondence
<br /> dated July 8, 1997 The work plan addtndum was approved by Mr Rowe in correspondence dated July 27, 1998
<br /> The Second quarter, 1999 monitoring described in this report is the seventh quarterly groundwater monitoring
<br /> event and the fourth surface water sampling event to be conducted at the site This report was prepared at the
<br />' request of Mr David Smith of]legman & lielcn s Marina
<br /> I aboratory analyses of the groundwater and surface water samples included benzene, toluene, ethyl ben/ene and
<br /> total xylenes (B rFX) total petroleum hydrocarbons quantified as gasoline ( 11111-G) and selected gasoline
<br /> oxygenatL1,'addi1i.es Ihis report includes a site history, a summary of the current monitoring, client (including a
<br /> description of the sampling and laboratory analytical results), and a summary with conclusions
<br />' 2. SITE BACKGROUND
<br /> On October 30, 1991, Warren L Gomes 1 xcavating, Inc , of Rio Vista, California, excavated and removed three
<br />' underground storage tanks (USTs) from the site (Figure 2, Appendix A) The USTs (TKI, TK2, and TK3)
<br /> contained gasoline and diesel fuel A small hole was found on the lower fill end of TK3 (diesel tank) Petroleum
<br /> staining and odors N�Lre noted in the soil beneath the former locations of the USTs Six soil samples were
<br />' collected by Condor from the UST excavation at depths of 9 to 12 feet below the ground surface Laboratory
<br /> analyses indicated elevated concentrations of 1 PI I-G, B I LX, and total extractable petroleum hydrocarbons
<br /> quantified as diesel (TI PH) in the soil samples
<br /> IOn August 22, 1995, three hydropunch borings were drilled at the site Gasoline odors were noted in each
<br /> borehole Laboratory analyses indicated concentrations of rPH-Cl 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, BTEX, and methyl tertiary butyl ether (MTBE) were present in soil acid
<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 latc,ral extent of the gasoline and diesel contamination plume in the
<br /> groundwater On September 10 1997, ( ondor installed four monitor wells at the site The Repot t - Additional
<br /> Swl and (,i oundii utel 1ni etiligalwn dated December 11, 1997 was prc,parc.d by Condor to d(,sQWK the
<br /> investigation results lu—w
<br />' 4i CONDOR
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