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BTEX analytes by EPA Method 602. Appropriate chain-of-custody Procedures were adhered to at all times during sample procurement and handling. The samples were extracted and =" analyzed within the lifespan limits set forth by EPA guidelines for the specified analyses. Samples of the surface waters in Fourteen-Mile Slough to the west of MW-6 were collected on January 13, 1995. The sampling methodology was similar to that utilized when sampling �`A monitoring wells, except that a bailer was not used. The geologist filled the containers directly r-- from the shore of the slough, just upgradient of MW-6 (see Figure 3F). Care was taken to ensure that no air space existed in the hand-filled vials by inverting, tapping, and checking for bubbles. Each container was properly labeled in the field and refrigerated for transport to Sherwood Labs in Hilmar for TPH-g by EPA Method 503018015-mod; TRPH-d analysis by EPA Method 351018015-mod; and BTEX analytes by EPA Method 602. Appropriate chain-of-custody procedures were adhered to at all times during sample procurement and handling. The samples 7:. were extracted and analyzed within the lifespan limits set forth by EPA guidelines for the specified analyses. Analytical Results r:A Ground-water samples collected from the three wells were received at Sherwood Labs on September 19 and December 16, 1994. The surface water sample was received at the laboratory on January 13, 1995. The analytical results have revealed wholly nondetectable concentrations of TRPH-d analytes and nondetectable results for TPH-g and BTEX analytes in samples collected from wells MW-4 and MW-5 on all sampling occasions. The results of the analyses of the samples collected from MW-6 indicate that the ground water underlying that vicinity remains impacted with TPH-g and benzene analytes above the Maximum Contaminant Levels (MCLS) set by the California Department of Health Services. It should be noted that TPH-g and benzene concentrations had declined on September 19 but had returned on December 15 to near their initial levels of June 20. The analytical results for these sampling activities are summarized _j in Table 3. The Sherwood Labs analytical reports and chain-of-custody are included as " - Appendix endix B. 4: 1. I ! `1 W.W. Irmn, Inc. Project No. 33016.04 r January 1995 g J C-;