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Soil samples collected from MW3 contained very low levels of benzene, toluene, xylenes, and total petroleum hydrocarbons. Soil samples from MW4 and MWS contained nondetectable levels of these fuel constituents. 2.3 INSTALLATION OF MONITORING WELLS Monitoring wells MW1 , MW2, and MW3 were completed with nominal 2- inch PVC casing; Wells MW4 and MWS, with 4-inch casing. Screened casing was installed from 30 to 70 feet below the ground surface. The screened intervals "were packed with sand, and the filter pack was sealed with a layer of bentonite pellets. A neat cement grout seal was pumped into the remaining annular space from the j bentonite seal to the surface. The well tops were completed with i traffic boxes set in concrete. The wells are ,further secured i with locking well. caps and padlocks. Vhe completion details of each well" are illustrated in the boring logs (see Appendix A) . ^� 2 4. SAMPLING AND ANALYSIS OF GROUNDWATER i .,„. wells MW1 and MW2 were first sampled on , 13 November 1985, and MW3 was -first sampled. on 13 November 1986 (Table 3 ). Wells MW4 and 4W5_"were first sampled on. 26 .June 1987, and wells MW1 ; t+iw2, and MW3 were resampled. These samples were collected and submitted for analysis by GTI- " The monitoring wells were developed. with hand bailing methods: and then .sampled with a clean Teflon bailer. All. samples were handled and submitted to analytical laboratories. according to'.GTI's., standard operating procedures (GTI 1986b) In _February EA_ began_ .samp_l.ing ..water from all of the muni- toting wells on a quarterly basis (Table 3 ) _ EA employed .its t .. standardrocedure p for sasu.,J.ing monitoring wells at the site- Before sampling, 3-5 casing volumes of water were purged from each well, using PVC bailers. . The .equipment used in purging the ji wells was thoroughly cleaned with .trisodium phosphate detergent e25/71050/8-89 /t 8 i