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IQUARTERLY GROUNDWATER MONITORING REPORT • FIRST QUARTER, 2000 ' Herman. & Helen's Marina Venice Island Ferry Stockton, CA April 20,2000 r1 INTRODUCTION On March 17, 2000, C ondor I~arth Iechnologies, Ini- (Condor) conducted quarterly groundwater and surface water monitoring at HLrinan & Helen's Marina located at Venice Island Ferry in Stockton, California (Figures 1 and 2, Appendix A) rhe work described in this report was conducted in accordance with sampling procedures included in the Work Plan - 'donator Well Installation and the Work Plan Addendum, prepared by Condor and dated May 30, 1997, and July 9, 1998, respectively I he work plan was conditionally approved by Mr Ronald Rowe of the San Joaquin County Public Health Services/Environmental Health Department (PHS/F HD) in correspondence dated July 8, 1997 The work plan addendum was approved by Mr Rowe in correspondence dated July 27, 1998 The first quarter, 2000, monitoring described in this report is the tenth quarterly groundwater monitoring event and the seventh surface water sampling event to be conducted at the site This report was prepared at the request of Mr David Smith of Herman& Helen's Manna The groundwater and surface water samples collected during the first quarter, 2000 monitoring event were laboratory analyzed for benzene, toluene, ethyl benzene and total xylenes (BTEX), total petroleum hydrocarbons quantified as gasoline ( IPII-G), and selected gasoline oxygenates/additives This report includes site background information a summary of the current monitoring event (including a description of the sampling and laboratory analytical results), and a summary with conclusions 2 SITE BACKGROUND On October 30, 1991, Warren E Gomes Excavating, Inc , of Rio Vista, California, excavated and removed three underground storage tanks (USTs) from the site (Figure 2, Appendix A) The USTs (TKI, TK2, and TK3) contained gasoline and diesel fuel A small hole was found on the lower fill end of TK3 (diesel tank) Petroleum staining and odors were noted in the soil beneath the former locations of the USTs Six soil samples were collected by Condor from the UST excavation at depths of 9 to 12 feet below the ground surface I,aboratory analyses indicated elevated concentrations of TPH-G, BTEX, and total extractable petroleum hydrocarbons quantified as diesel (TEPH) in the soil samples On August 22, 1995, three hydropunch borings were drilled at the site Gasoline odors were noted in each borehole Laboratory analyses indicated concentrations of TPH-G and BTEX in the soil and groundwater I samples analyzed from each borehole Based on the results of the August 1995, investigation, Condor recommended additional investigation be conducted to evaluate the extent of the hydrocarbon plume On August 29, 1996, five Geoprobe boreholes were installed at the site The results of the laboratory analyses indicated that elevated concentrations of TPH-G, BTEX, and methyl tertiary butyl ether (MTBE) were present in soil and groundwater samples collected from the northern portion of the site and that further investigation was necessary to evaluate the extent of soil and groundwater contamination IBased on the results of the Geoprobe investigation, Condor recommended that monitor wells be installed at the site to investigate and monitor the lateral extent of the gasoline and diesel contamination plume in the groundwater On September 10, 1997, Condor installed four monitor wells at the site The Report - Additional 1 � �� CONDOR