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0 <br /> • <br />' split-spoon sampler will be cleaned with phosphate-free soap and rinsed with water following each <br /> sample collection Soil cuttings generated during drilling operations will be placed on and covered <br /> with visqueen or in 55-galoon DOT drums on site until laboratory results are obtained and proper <br />' methods of disposal have been approved <br /> 3 0 SOIL SAMPLE SCREENING <br /> After the vapors in the soil samples are allowed to equilibrate with the air in the headspace of the <br /> plastic bags, the organic vapors within the headspace will be screened with a PID or flame <br /> ionization detector equipped with a 10 6 eV lamp calibrated to isobutylene The sample bag will <br />' be opened and the detector probe immediately placed within the headspace of the bag The <br /> highest observed reading will be recorded This number provides a relative comparison of the <br /> petroleum hydrocarbon concentration with the soil samples but is not quantitative The field <br />' readings will be recorded on the boring logs <br /> The soil samples will be selected for laboratory analysis on the basis of organic vapor screening <br />' results and field observations Selected soil samples will be submitted to a state certified <br /> laboratory for analysis of benzene, toluene, ethylbenzene, and total xylenes (BTEX) using EPA <br /> Method 8021 B, total petroleum hydrocarbons as gasoline (TPHg) concentrations using EPA <br /> Method 8015 Modified, and oxygenate compounds using EPA Method 82608 <br />' 4.0 WELL CONSTRUCTION <br />' 4.1 Monitoring Well Filter Pack and Slot Size Selection <br /> The filter pack material of each well will be selected to permit the development of a zone of <br />' higher hydraulic conductivity adjacent to the well screen, but not allow piping of the <br /> finer-grained formation materials into the well The slot size of the monitoring well screen will <br />' be selected such that it will retain a minimum of 95 percent of the filter pack material <br /> 4 2 Monitorma Well Development <br /> After the monitoring wells are installed, each well will be developed either prior to emplacement of <br />' the bentonite seal and cement grout, or after a period of 72 hours to allow the grout seals to cure <br /> Development will be performed using a surge block and submersible pump until the water <br /> produced will be relatively sediment-free All water produced from the wells during development <br /> will be placed in drums on site for later disposal <br />