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i liLnnin Bc HLIYn , Vi inu rhird QunrrLr 2000 {,roundwater Monironng (Xt0be7 S7 2000 i P,« • Soul and hli c stivution dated DLLetnbet 1 1 1997 \ras prepared by Condor to describe thy, iinvestigation ILsUlts 11'1141 13 11 h L0t1stitLILIIts M 11-11 tertiary butanol and tcrtiary amyl methyl ether ( I AML-) ',A Lre deteeted in some cif the soil and groundwater Samples collected during the investigation Groundwater elevation data i indicated that groundwater flow at the, site kivas probably controlled by the very active Island drainage pumping system adjacent to the site Ihr. above rc,terenced report recommended quarterly groundwater monitoring surfaee water trampling and Risk Based Corrc.ctive ALtion (RBCA) to furihLr characterrzL the tine and to ievaluate options for remediation or site closure i In a telephone, conversation on 'March 23, 1998, Mr Ronald Rowe of the San Joaquin County Public Health Services/1 nvironn ital Health Department (PHS/1 HD) indicated that, based on his review of the report dated December 1 1 1997 (ieterenced above) lie was requesting that quarterly groundwater monitoring continue at the site Furthermore lie requested that a work plan be prepared for conducting quarterly surface water sampling iand additional investigation of the gasoline oxygenate/additive plume to the east of monitor well MW-2 Condor subsequently prepared the Work Plan Additional.Sod and Groundwater InvestigationlSurface Water ''amphng, dated May 27, 1998 In a fax dated June 1, 1998, Mr Rowe approved the work plan with the stipulation that a iwork plan addendum be prepared describing installation of additional borings to those proposed in the work plan and grab sampling of the Herman & Helen's Marina drinking water source Condor subsequently prepared the Work Plan Addendum dated July 9, 1998 In a fax dated July 27, 1998, Mr Rowe approved the work plan ' addendum adding that both the facility pre-treated drinking water and the post-treatment water should be sampled and analyzed by appropriate methods On OLtober 1 1998 a Condoi representative was on site to conduct quarterly surface water sampling activities and collect a sample of the marina's pre-treated and treated drinking water from the facility s water treatment system From December 1998, through Juni~ 2000, Condor conducted quarterly groundwatei and surface water isampling In a letter dated June 30, 2000, Mr Rowe directed the submittal of a work plan amendment to modify the scope i of work proposed in the above referenced woi k plan and work plan addendum According to Mr Rowe, the work plan amendment was to describe vertical characterization of the potential MTBE plume and be submitted by August 1 2000 In addition, Mi Rowe required that a report of the work be submitted by September 1 2000 ' C ondor subsequently prepared the status Repo t and Addendum to the Work Plan, dated July 24 2000 Mr Rowe approved the woik plan amendment in a tax dated August 3, 2000 1n a telephone e,onvc.isation with Mr Rowe on August 3 2000 Condor requested that the submittal date for the report of findings be extended to I October 6, 2000 Mi Rowe verbally concurred with the extension and requested that Condor prepare a letter to document the conversation Condor followed up with a letter dated August 3, 2000 The installation and sampling of the soil borings described by the Work Plan, Work Plan Addendum, and Work Plan Amendment Soil were conducted at the site between September 1 1 and September 13, 2000 Direct push (Geoprobe), hand auger and hollow-stern auger techniques were used to advance 13 borings at the site (Borings DP-1 through DP-9 SP-1, and HP-1 through HP-3) for the purpose of collecting soil and groundwater samples The ic.sults of the investigation weic described in the Sod and Groundtiiater Investigation and Semali c Receptor Surrey Report, dated Octobei 2, 2000 The results of the investigation generally indicated that the MTBE plume to the east of the site appears to be significantly influenced by the surface water drainage and pumping to the east and south of the site Relatively low concentrations of MTBF, however, were present in groundwater beyond the • drainage ditch to the east of the site The sensitive receptor survey did not indicate any readily identifiable sensitive receptors within a radius of 2,000-feet around the site (other than the surface water bodies adjacent to the site) Based on the results of the investigation, Condor recommended additional investigation to confirm the t� CONDOR