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i Hr.rrnaD& IIL[Cn s Manna-1-irst Quarter 1999 Groundwater Monitorutg April 15 1999 Page 2 TPH-G RTEX e.an5tituents, MTBE tertiary butanol, and tertiary amyl methyl ether (1 AME) were detected in some of the soil and groundwater samples collected during the investigation Groundwater elevation data indicated that groundwater flow at the site was probably controlled by the very active island drainage pumping system adjacent to the site The above referenced report recommended quarterly groundwater monitoring, surface water sampling, and Risk Based Corrective Action (RBCA) to further characterize the site and to evaluate options for remediation or site closure In a telephone, conversation on March 23, 1998 Mr Ronald Rowe of the San Joaquin County Public Health Services/Environmental Health Department (PIIS/EHD) indicated that, based on his review of the report dated December 1 1 1997 (referenced above), lie was requesting that quarterly groundwater monitoring continue at the site Furthermore, lie requested that a work pian be prepared for conducting quarterly surface water sampling and additional investigation of the gasoline oxygenate/additive plume to the east of monitor well MW-2 Condor subsequently prepared the Work Plan — 4dditronal Soil and Groundwater InvestigationlSurface Water Sampling dated May 27, 1998 In a faxed note dated June 1, 1998, Mr Rowe approved the work plan with the stipulation that a work 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 Ron 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 October 1, 1998, a Condor 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 On December 30, 1998, Condor again conducted quarterly surface water sampling as part of the fourth quarter, 1998, monitoring The installation and sampling of the soil borings described by the above referenced Work Plan and Work Plan Addendum is pending receipt of site access authorization from off-site property owners A comprehensive site background is included in Appendix B 3. FIRST QUARTER, 1999,GROUNDWATER MONITORING 3 1 FIELD METHODOLOGY On March 26, 1999, a Condor representative was on site to conduct quarterly groundwater monitoring activities The monitoring activities included measurement of water levels in the site monitor wells and at surface water measurement stations and the collection of groundwater samples from the monitor wells All field equipment ' was decontaminated in the field with a solution of laboratory-grade, non-phosphate detergent and hydrocarbon- free water and rinsed with hydrocarbon-free water prior to use in each well All field instruments were calibrated to the manufacturer's recommended standards The water level in each well was measured to the nearest 0 01 foot with a battery-operated, flat-tape, water-level meter A new, disposable, polyethylene bailer was lowered into each well to collect a field-inspection sample The bailer sample was inspected for floating product, sheen, discoloration and/or odor Floating product or sheens were not observed in the groundwater removed from any of the monitor wells during the groundwater sampling Petroleum hydrocarbon odors were not noted in the groundwater samples collected from the four monitor wells The purging and sampling sequence for the monitor wells was MW-1, MW-3, MW-2, and MW-4 Each well was purged with a new, disposable, polyethylene bailer until three well-casing volumes of water had been removed and the electrical conductivity, pH, and temperature of the water had stabilized The purge water was discharged to 55-gallon drums and left on site to await disposal Groundwater Monitoring Field Forms are included in Appendix C A groundwater sample was collected from each well by filling a new, disposable, polyethylene bailer with groundwater and transferring the groundwater to two 40-milliliter glass vials fitted with Teflon-lined The 4F% 4%Nft It, CONDOR