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April 16, 1992 - Initial groundwater measuring and sampling of <br /> the three wells revealed that BTEX, TPH-G, & TPH-D were below <br /> detection limits Hydraulic gradient to the west <br /> May 30, 1996 - One soil boring was advanced to 801bgl in the spot <br /> where the two UST' s had been, it ' s location is shown on PLATE I . <br /> Laboratory analyses revealed significant levels of TPH as diesel <br /> & gasoline in most of the samples, benzene & toluene were below <br /> detection levels, but minor amounts of ethylbenzene & xylene were <br /> measured in some of the samples Refer to the report titled <br /> °INTERIM INVESTIGATION REPORT MARCI ' S DIESEL SERVICE " dated <br /> August 17, 1996 prepared by Lush Geosciences for details of that <br /> work <br /> October 10, 1996 - MW-1 was purged & sampled by Del-Tech Geo- <br /> technical Support Services Results were as follows benzene - <br /> ND, toluene - ND, ethylbenzene - ND, & xylene - 1 3 ug/L. MTBE & <br /> TEPH were ND, and TPHg was not anlyzed However, due to an <br /> unknown reason, a minor amount of contamination was detected in <br /> the baler blank, and it was decided to resample the well <br /> . November 27, 1996 - MW-1 was again sampled by Del-Tech, the <br /> results showed benzene - ND, toluene - ND, ethylbenzene - 0 .4 <br /> ug/L, xylene - 0 . 8 ug/L, and TPHg - 222 ug/L TEPH was ND, and <br /> MTBE was not identified <br /> PROPOSED WORKPLAN <br /> NOTE All field operations will be supervised by properly <br /> licensed personel, and witnessed as required by a representative <br /> of the San Joaquin Co EHD. <br /> 1 Move in properly licensed auger rig & crew on the location <br /> shown on PLATE I for monitoring well ##4 Equipment to include <br /> sufficient clean 10" OD hollow stem augers to complete well <br /> without additional decontamination Sampling equipment to <br /> consist of two (2) California modified split-spoon core barrels <br /> designed to hold 2" or 2 1/2 " OD metal sleeves <br /> 2 Soil samples to be taken at 10 ' intervals from 10 ' bgl to the <br /> capillary fringe, which is estimated to be between 65 ' and 80 ' <br /> bgl <br /> 3 . Upon reaching groundwater, a weighted tape or electronic <br /> device will be run to verify water level After wasting 10-15 <br /> minutes, the level will be checked again San Joaquin County EHD <br /> personel will be notified prior to completing well <br /> 3 <br />