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Geologual7ecknccs Inc Page 2 Soil Gas Survey Report Project No 701 2 July 23, 2002 ' 1.0 SOIL GAS SURVEY Ms Julie Hedegard of Manteca, executor of the estate that owns the property west of the Ted Peters property, was contacted for permission to access the property to perform the survey Permission was received on May 9, 2002 A passive soil gas survey (SGS) was performed on the northwestern portion of the Ted Peters property and the Hedegard Property from May 23 through June 13, 2002 The methodology and results are outlined as follows 1.1 Method Soil gas modules, called "GORE-S ORBERS", manufactured by W L Gore & Associates, were used at this site - see Figure 2 for grid location The GORE-SORBER consists of a hollow insertion/retrieval cord made of GORE-TEX ePTFE Inside the cord are smaller, hollow ePTFE tubes filled with carbon and resin absorbent material The soil vapors travel through the insertionlretneval cord and into the absorbent material while water and soil particles are excluded The individual modules are inserted into a 1-inch diameter 36-inch deep hole, then the hole is plugged with a cork and the module is left in the ground for approximately two weeks At the end of this period the module is then retrieved, placed back in its sample container and shipped to the W L Gore Laboratories in Elkton, Maryland Upon receiving the ' modules, the laboratory checks them in and then stores them in the freezer until the analysis is ready to be performed Typical analysis is by gas chromatography/mass spectroscopy A report is then issued by Gore that includes a site map upon which the chemical constituents ' of concern have been contoured The Gore report and maps are included in Appendix A On May 23, 2002, Joseph Angulo of GTI and Don Light of Del Tech mobilized to the site ' A grid was laid out on five transect lines with 20 sample points and an approximate spacing of 50 feet between modules One inch diameter, 36-inch deep holes were drilled with a roto hammer and the modules were inserted A total of 20 modules were inserted, 2 modules ' were not used and served as trip blanks Care was taken to eliminate the possibility of cross contamination between holes The following quality assurance practices were used ' • The drill bit was washed in water with Alconox and then double rinsed with clean water between the drilling of each hole ' • Clean disposable nitrile gloves were worn when washing and handling the drill bit • Clean disposable nitrile gloves were worn for the installation and removal of each module 1