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er _ <br /> ARCADIS Ms. Lisa Medina <br /> June 22, 2012 <br /> will involve measuring approximately 30 grams from a relatively undisturbed soil <br /> sample and placing this sample in a sealed container(zip-lock bag). The bag will be <br /> warmed in the sun for approximately 20 minutes, then the head space within the bag <br /> will be tested for total organic vapor, measured in parts per million. The PID results <br /> will be recorded on the field boring logs. <br /> Although PID measurements are useful for indicating relative levels of impact, the <br /> measurements cannot be used to evaluate hydrocarbon levels with the confidence of <br /> laboratory results. Therefore, soil samples will be collected from the sampler for <br /> laboratory analysis based on PID measurements and/or visual characteristics <br /> (i.e. staining, odors, sheen). Select soil samples will be collected in brass, stainless <br /> steel or plastic liners, capped with Teflon®squares and plastic end caps and sealed <br /> in zip-lock bags. The samples will be placed on ice, cooled to approximately 4 <br /> degrees Celsius(°C), and transported to a State of California certified laboratory <br /> under chain-of-custody documentation. The soil samples will be analyzed for the <br /> following constituents: <br /> • Total petroleum hydrocarbons quantified as gasoline range organics <br /> (TPH-GRO [C6-C12D by United States Environmental Protection Agency <br /> (USEPA) Method 80158 modified <br /> • Benzene, toluene, ethylbenzene, and total xylenes (BTEX)by USEPA <br /> Method 8260B <br /> • Methyl tertiary butyl ether(MTBE)and 1,2-dichloroethane(1,2-DCA) by <br /> USEPA Method 8260B <br /> Down-hole drilling and sampling equipment will be steam-cleaned following the <br /> completion of each soil boring. Down-hole equipment will be washed in a tri-sodium <br /> phosphate or Alconox solution between samples. <br /> 4.5.3 Well Installation Construction <br /> Upon completion of the soil boring, the extraction well and monitoring point will be <br /> constructed using 4-inch OD Schedule 40 polyvinyl chloride(PVC)casing with the <br /> anticipated screen intervals specified above. A 2/16 sand filter pack will be placed in <br /> the boring annular space from the bottom of the borehole to approximately 2 feet <br /> above the screen interval, followed by approximately 2 feet of transition sand (1C), <br /> overlain by 100-percent neat cement grout to the surface. Transition sand is being <br /> Page: <br /> G VycgffNVBRLPtO58515 D9iva,WbWM Rea\SVE plWbpwkpeALF.f 1'NY!]EP-SVERWTMWR6 5/9 <br />