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Upon recovery, a portion of the soil sample is placed into a plastic bag and sealed for later <br /> screening with a photo ionization detector (PID) Another portion of the soil sample is used for <br />' classification and description <br /> The soil sample is collected, labeled, and handled according to the Quality Assurance Plan A <br /> geologist from ENSR continuously logs (if required) each borehole using the Soil Classification <br />' Method Section during advancement and constantly checks soil samples for indications of first <br /> recognizable occurrence of groundwater <br />' Soil Classification <br />' As the samples are obtained in the field, they are classified by the geologist in accordance with <br /> the Unified Soil Classification System (USCS) Representative portions of the samples are <br /> retained for further examination and for verification of the field classification Logs of the borings <br />' indicating the depth and identification of the various strata, and pertinent information regarding <br /> the method of maintaining and advancing the borehole are made <br /> Soil Sample Screening <br /> A portion of the soil sample from each sample tube is placed in a resealable plastic bag After <br /> 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 are screened with a flame ionization <br />' detector or photo ionization detector The sample bag is opened, and the detector probe <br /> immediately placed within the headspace of the bag The highest observed reading is recorded <br /> This number provides a relative comparison of the volatile organic compounds concentration <br />' with the soil samples but is not quantitative The field readings are recorded on the boring logs <br /> WELL DEVELOPMENT <br />' This section describes the field and analytical procedures to be followed by ENSR throughout <br /> the investigation <br /> General Well Development Procedures <br />' The water level and well depth is measured with a water level indicator and written on the well <br /> development record This information is used to calculate the volume of standing water (i e , the <br />' well volume)within the well <br /> Drilling fluids such as mud or water, if used during the drilling and well installation process, are <br /> removed during the well development procedure It is recommended that a minimum of 1 5 <br /> times the volume of added fluid be removed from the well during development Drilling muds <br /> are initially flushed from the drilling casing during the well installation procedure with water <br /> e added during the flushing process If the quantity of added fluid is not known or could not be <br /> reasonably estimated, removal of a minimum of 10 well volumes of water is recommended <br /> during the development procedure <br />