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a Undisturbed soil samples were collected every 5-feet as drilling progressed for lithologic and hydrogeologic description and for possible chemical analysis. The samples were collected by driving a split-barrel sampler lined with 6-inch diameter brass tubes using repeated blows from a 140-1b hammer dropped 30-inches. Selective soil samples were immediately trimmed, sealed with Teflon tape and plastic end caps, labeled, and stored on ice for transport to Kiff under chain of custody. Soil from the remaining tubes was described by the site geologist using the USCS and was screened for volatile compounds using an OVM. The soil was screened by emptying soil from one of the sample tubes into a plastic bag. The bag was then sealed and placed in the sun f o r approximately 10 minutes. After the volatile compounds were allowed to volatilize, the OVM measured the vapor in the bag through a small hole punched in the bag. OVM readings are used as a screening tool only, since the procedures are not as rigorous as those used in the laboratory. The OVM readings are listed on the boring logs presented in Appendix D. Drilling equipment was cleaned with a TSP solution between sampling intervals to prevent potential cross-contamination. 6.3.2 Air Sparge Well Construction Air sparge well AS-I was constructed within the hollow stem augers using 2-inch diameter flush-threaded, schedule 40, 0.020-inch slotted PVC well screen and blank casing. The well was screened between 14 and 16-feet bgs to allow for the injection of air at the very bottom of the water- bearing zone. The well casing was lowered through the augers and #2/12 filter pack sand was placed in the annular space between the well casing and the borehole from the bottom of the boring to 1.5-foot above the screened interval. A 2-foot thick layer of bentonite pellets were placed on top of the sand pack. Cement was used to fill the annular space between the bentonite layer and the surface to prevent surface water- from infiltrating into the well. The well head is protected with a locking well plug beneath an at-grade, traffic-rated well box. Well construction details are shown on the boring log in Appendix D. 6.4 —Nanor Extraction_ Well InstaIa iDD ASE installed vapor extraction wells VE-I and VE-2 to conduct a vapor extraction test. Details o{ the well construction are presented below. 774 West Grant Line Road CAP — January 2002 -10-