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1 <br />' Quality Assurance Plan Water generated during the monitoring event is disposed of <br /> according to the accepted regulatory method pertaining to the site <br /> 1 � <br /> SOIL VAPOR SAMPLING <br />' Soil Vapor Extraction wells are purged using a vacuum pump until a minimum of three well <br /> volumes of air has been removed Purge volumes are calculated based on the volume of <br />' the tubing making up the sample line If three well volumes cannot be removed or if the <br /> well screen is submerged samples are not collected The air sample is collected in a <br /> Summa Canister, labeled and handled according to the Quality Assurance Plan <br /> LOCATING UNDERGROUND UTILTITIES <br /> Prior to commencement of any work conducted below surface grade, the location of the <br /> borings is marked with white paint as required by law An underground locating service <br /> such as Underground Service Alert (USA) is contacted The locating company contacts <br /> the owners of the various utilities in the vicinity of the site to mark the locations of their <br /> underground utilities <br /> • DRILLING AND SOIL SAMPLING <br />' Hollow Stem Auger Soil Borings <br /> Soil borings and soil sampling are performed under the direction of an ENSR geologist <br />' The soil borings are advanced using a truck mounted hollow-stem auger drill rig <br /> To reduce the chances of cross-contamination between boreholes, all down hole drilling <br />' equipment is steam-cleaned between each boring To reduce cross-contamination <br /> between samples, the split-spoon sampler is washed in soap solution and double rinsed <br />' between each sampling event <br /> Sod sampling beyond 5 feet bgs is conducted in accordance with ASTM 1586-84 Using <br /> this procedure, a 2-inch outside diameter split spoon sampler or a 2 inch msiria rhameter <br /> California -type sampler is driven into the soil by a 140-pound weight falling 30 inches <br /> After an initial set of 6 inches, the number of blows required to drive the sampler an <br /> additional 12 inches is known as penetration resistance, or the "N" value The N value is <br /> used as an empirical measure of the relative density of cohesionless sods and the <br /> consistency of cohesive soils <br /> I <br />