SITE INFORMATION AND CORRESPONDENCE_FILE 1

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was washed with trisodium phosphate detergent and then rinsed with deionized water. The drilling equipment was steam cleaned before each borehole was drilled. The boreholes were completed as ground-water monitoring wells with PVC screen ( 4-inch diameter, 0 . 020 inch slot, Schedule 40 ) from approximately 10 feet above to 10 feet below the static ` water level . The lithology of the boreholes and construction details of the wells are shown in Appendix A. From the top of the screen to ground surface, the casing was completed with PVC Schedule 40 blank pipe with threaded joints. Each well casing r was equipped with a threaded plug on the bottom and a slip cap at the top. The annular space from the bottom to approximately 2 feet above the screen was filled with #3 Monterey clean sand. The sand pack was sealed with one to three feet of hydrated ben- tonite pellets, and a surface seal was created with a neat cement grout to just below ground surface. Each well was secured with a frame lock and a watertight cover, both set in concrete. The well cover can be opened only with a special wrench. A tag with pertinent information about the well was placed in each well box. The new wells were located and surveyed using the top of casing of MW4 as a datum--approximately 8 . 13 feet above mean sea level from previous surveying. 2 . 2 WELL DEVELOPMENT AND WATER SAMPLING After completion, the wells were purged and developed with a 3- inch PVC bailer by removal of 3 to S volumes of standing water. After purging, both the existing and the new wells were sampled. Samples were collected with a clean Teflon bailer rinsed with deionized water. First, three bailer volumes were discharged, and then the fourth was poured into the container in such a way that no air bubbles were entrapped. The samples were collected in 40-m1 vials with hydrochloric acid ( HCL) as preservative to be analyzed for benzene, toluene, xylenes, and ethylbenzene, and in e20/73942 3