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i <br /> • <br /> ATTACHMENT A <br /> FIELD PROCEDURES (CONTINUED) <br /> Chevron Service Station 9-1452, 334 East Main Street, Ripon, California <br /> Well Destruction <br /> Monitonng wells MW-1, MW-2, and MW-3, upon approval from SJPHS and the RWQCB, <br /> will be destroyed by pressure grouting from the bottom up, and then dulling out the top five <br /> feet of each well The wells will have the well boxes removed and will be finished to surface <br /> grade with cement <br /> Soil Cuttings and Rinsate Water <br /> Soil cuttings generated during dulling operations will be temporarily stored onsite and <br /> covered with plastic sheeting pending charactenzation and disposal Chevron's disposal <br /> contractor will remove soil cuttings to an appropnate disposal facility Water generated <br /> during steam cleaning will be temporarily stored in DOT-approved 55-gallon drums pending <br /> transport by Chevron's disposal contractor to an appropnate disposal or treatment facility <br /> Soil cuttings and rinsate water drums will be temporarily stored onsite for approximately 4 to <br /> 8 weeks <br /> Organic Vapor Procedures <br /> Soil samples collected continuously dunng drilling will be analyzed in the field for ionizable <br /> organic compounds using a photo-ionization detector(PID) with a 10 2 eV lamp or a flame <br /> ionization detector(FED) The test procedure will involve measuring approximately 30 <br /> grams from an undisturbed soil sample, placing this sub-sample in a sealed container (either <br /> a zip-lock bag or a mason jar) The container will be warned for approximately 20 minutes <br /> (in the sun), then the head-space within will be tested for total organic vapor, measured in <br /> parts per million as benzene (ppmv; volume/volume) The instrument will be calibrated prior <br /> to drilling using a 100-ppm isobutylene standard (in air) and a sensitivity factor of 55, which <br /> relates the photo-ionization potential of benzene to that of isobutylene at 100 ppm The <br /> results of the field-testing will be noted on the boring logs PID and FID readings are useful <br /> for indicating relative levels of contamination, but cannot be used to evaluate hydrocarbon <br /> levels with the confidence of laboratory analyses <br /> • <br /> 2 <br />