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' Soil in the next sample tube (where available) should was to describe the lithology and measure volatile organic compound (VOC)concentrations Approximately half of the sample from the sample tube was removed and placed in a resealable ' plastic bag The plastic bag was set aside to allow VOCs, if present, to accumulate in the headspace above the sampled soil The headspace was then sampled using a portable photo-ionization detector(PID) The PID probe was inserted through a hole made in the plastic bag and the highest measurement encountered recorded on the boring log • Soil and wastewater generated during the field activities was contained in 55-gallon United Nations approved drums Well Construction Procedures • The monitoring wells were constructed of flush pointed, threaded, 2-inch I D , Schedule 40 polyvinyl chloride (PVC) casing The well casing was delivered to the 1 site in factory plastic wrap The casing had rubber or Teflon O-ring gaskets at the joints • The slotted interval consists of 0 020-inch machined slots The filter pack consists of#3 Monterey Sand The slot size and filter pack had been selected with the intent to minimize the amount of native lithologic and filter pack material entering the monitoring well • A bottom screw cap was placed on the bottom of the casing A 10 foot length of slotted casing was joined to the bottom screw cap The screened interval was set so that no more than 10 feet or no less than 7 feet of well screen is within the water-bearing zone Blank casing was used to construct the remainder of the well During placement of the filter pack, the well was suspended in the augers The augers were lifted 2 to 4 feet and the sand filter pack poured into the annulus The 1 augers were then slowly lifted with sand filter pack placed "continuously" until the sand is approximately 2 feet above the top of the screen The well was swabbed following placement of sand with a surge block Swabbing was conducted over the screened interval of the well casing, beginning at the bottom of the well Swabbing was conducted at least twice over the entire length of the well screen • An approximately 1 to 2 foot thick zone of bentonite was placed above the sand filter pack • The annulus above the bentonite was grouted with a cement slurry placed by tremmie if significant water is present in the boring The cement grout should extend to a depth of approximately 1 foot below the ground surface 1 N lrancfp]1ProjectslProjects1880104011a101101Assessment and Interim Remedial Report doe ' B-2