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■�L'I��`i11 N� <br /> 3.0 GROUNDWATER SAMPLING <br /> The following sections describe the groundwater sample collection, groundwater <br /> laboratory analytical results, and waste storage and disposal Samples were collected according <br /> to the sampling and analysis plan submitted in Versar S Site Investigation Workplan, dated <br /> August 2, 1995, and workplan addendum, dated May 10 1996 <br /> 31 Groundwater Sample Collection <br /> On May 29, 1996, groundwater samples were collected from the three groundwater <br /> monitoring wells at the Site Prior to purging and sampling. groundwater levels in monitoring <br /> wells MW-1, MW-2, and MW-3 were recorded at 42 57 42 60, and 42 31 feet bgs, respectively <br /> Before sampling, each well was purged of approximately three casing volumes of water and the <br /> water was allowed to recover to at least 80 percent of its pre-purge level Data collected prior to <br />' and during purging and sampling were recorded on monitoring well purge tables included as <br /> Appendix A <br /> Samples were collected, placed in containers, preserved, and analyzed within the time <br /> constraints consistent with applicable regulatory agency requirements Samples were tracked <br /> using Versar's chain-of-custody forms The sampling team maintained custody of the samples <br /> from the time of collection until submittal to the laboratory <br /> 32 Groundwater Sample Analytical Results <br /> Three groundwater samples were collected and submitted for laboratory analysis for <br /> 1 TPH-D, TPH-G, BTEX, methyl tert-butyl ether (MTBE), and TPH-JP4 to Excelchem <br /> Environmental Labs, California certification #2119 <br /> TPH-D, TPH-G, BTEX, MTBE and TPH-JP4 were not detected above laboratory <br /> detection limits in the groundwater samples collected from MW-1 and MW-3 TPH-D and TPH- <br /> i JP4 were not detected in the groundwater samples collected from MW-2, however the detection <br /> limit for TPH-JP4 was 300 micrograms per liter (µg/l} instead of S l because of the <br /> laboratory methodology During the next sampling event, the detection limit for TPH-JP4 will <br /> be 50 µg/1 Concentrations of benzene at 0 76 p.g/l, xylenes at 0 76 µg11, TPH-G at 149 pg/l, and <br /> MTBE at 149 ug/l were detected in the groundwater sample collected from MW-2 Laboratory <br />' analytical results are summarized in Table 2, Appendix B contains a copy of the laboratory <br /> analytical report <br /> 1 <br />' P 0SAIST0CKT0N1337200 M STQTR RPT 6 <br />