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r y i Supplemental Investigation Report BP Oil Site No 11193 CAM B R I A Stockton, California October 13, 2000 Pumping Data To further evaluate this well, pumping data and analytical results were requested from Caltrans Sayed Hashemyan and Jim Morino of Caltrans were contacted but could not provide pumping or analytical data for the well Mr Hashemyan indicated during a May 24, 2000 conversation that a turbine pump in the well had been replaced by a submersible pump Andy Stephens of Stephens Construction indicated during a July 26, 2000 conversation that the submersible pump was set at the bottom of the well During a September 20, 2000 telephone conversation, Mr Stevens indicated that the Caltrans well had been destroyed Well Sampling On May 24, 2000, a groundwater sample was collected directly from the hose bib of the Caltrans well after running water through a hose attached to the hose bib for approximately 20 minutes, as requested by Carol Oz of the SJCEHD Generally, three casing volumes are purged from a groundwater well prior to sampling, however, based on the well diameter, the static depth to water of approximately 22 feet and a submersible pump intake depth of 340 feet bgs (10 feet above the total well depth of 350 feet),three casing volumes in the case of the Caltrans well would be over 4,000 gallons The samples collected are likely representative of a mixture of the standing water in the well casing and the formation around the screen interval Sayed Hashemyan of Caltrans and Carol . Oz observed sampling activities The sample was collected and analyzed for TPHg using Modified EPA Method 8015 and for BTEX,MTBE, TAME,DIPE, ETBE and TBA using EPA Method 8260 by Pace Analytical results are summarized on Table 3 and the analytical report is included in Appendix F No TPHg, BTEX, MTBE, TAME, DIPE or ETBE was reported in the groundwater sample TBA was reported at 11 Rg/l, with a method detection limit of 10 Rgll Sampling attempts on June 13 and July 24, 2000 were not successful because the submersible pump was not operable On June 13, 2000, the depth to water was approximately 22 feet bgs in the Caltrans well Upon removal,light oil was present on the water level indicator used for this measurement The oil on the water surface is likely due to operation of the previously installed turbine pump A second sample was collected from the Caltrans well on July 28, 2000 Bob Highfield of Stephens Construction observed the sampling activities Sample collection procedures were consistent with the previous sampling event, and the sample was analyzed for TPHg using modified EPA Method 8015 and BTEX, MTBE, TAME, DIPE, ETBE and TBA using EPA Method 8260 by Pace (see Table 3 and Appendix F) No BTEX, MTBE,TAME, DIPE, ETBE or TBA, and 270 pg/l TPHg were reported in this groundwater sample Pace noted that the hydrocarbons reported did not fit the TPHg profile 11