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14 August 2003 AGE-NC Project No. 01-0865 Page 3 of 6 All of the proposed soil borings with the exception of the boring near MW-5 will be advanced to the extent of contamination as determined by the presence of volatile organic compounds using an organic vapor monitor (OVM) equipped with a photo-ionization detector (PID: Thermo Environmental 580b, 10.0 eV, calibrated to isobutylene)to the maximum recoverable depth of the Geoprobe,optimally around 50-feet to 60-feet below surface grade(bsg).The boring proposed near MW-5 will be limited to 25 feet bsg. During the boring operation, soil samples will be collected continuouslybeginning at surface grade.Field procedures for advancement ofborings and collection of soil samples are presented in Section 4.2. Selected soil samples from each probe boring will be submitted for laboratory analysis. The soil samples will be selected for analysis by using a combination of 1) the relative OVM readings in a boring,higher readings and zones with radical changes in consecutive samples(increase or decrease) will have sampling preference and 2)samples within differing lithologies(e.g.peat verses silt).The number of samples analyzed per boring will depend on the soil borings total depth, but will be a minimum of every 15 feet and include the soil sample collected at total depth. The selected soil samples will be analyzed by a State of California Department of Health Services (DHS)-certified laboratory for the following constituents: • Total petroleum hydrocarbons quantified as gasoline and diesel(TPH-g and TPH-d)by EPA Method 8015 Modified; • Benzene, toluene, ethylbenzene and total xylenes (BTEX) fuel additives including methyl tertiary butyl ether(MTBE), tertiary-butyl alcohol (TBA), di-isopropyl ether(DIPE), ethyl tertiary-butyl ether(ETBE),tertiary-amyl methyl ether(TAME)ethylene dibromide(EDB) and 1,2-dichloroethane (1,2-DCA)by EPA Method 8260b; and • MTBE by EPA Method 1311 (TCLP). 3.3. GRAB GROUND WATER SAMPLE COLLECTION AND ANALYSIS First encountered ground water `grab' ground water samples will be collected from each boring during the boring process using a Geoprobe water sampling assembly. Samples will be collected into 40-m1 volatile organic analysis (VOA) vials with 0.5 ml 18% hydrochloric acid as a sample preservative and 1-liter amber bottles as appropriate for the required analyses; ground water sample collection procedures are presented in Section 4.3. Ground water samples will be analyzed by a DHS-certified laboratory for: • TPH-g and TPH-d by EPA Method 8015 Modified; Advanced GeoEnvironmenlal,Inc.