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Creologaal rech4ks Inc Page 5 0 Quarter 2001 Groundwater Monitoring Report Project No 5072 January 17, 2002 ' The results and detection limits for the above analyses are listed in Table 3 of Appendix A Y PP ' while the lab analytical results are presented in Appendix B As required under A132886, the laboratory data was submitted electronically to GeoTracker on December 28, 2001 - confirmation number 9838526189 2.0 FINDINGS AND DISCUSSION The results of the groundwater sample analyses indicate the following • Wells MW-1, MW-2 and MW-3 remain free of detectable contamination • MW-4, MW-5 and MW-9 have significant BTEX and TPH-G contamination • MW-6 and MW-8 have minor TPH-G or BTEX contamination • Water table well MW-7 did not contain contaminant concentrations above the laboratory limits This well previously contained 13 - 15 ug/l MTBE for the two events completed ' since the well was installed in May 2001 • Water table well MW-10 did not contain contaminant concentrations above the laboratory limits It contained 1 8 ug/l xylenes for the previous September event This is the third event completed since it was installed in May 2001 and the well had previously been non-detect for contaminants on June 1, 2001 o Deep well MW-109 contained minor BTEX, TPH-G and MTBE contamination for the third consecutive event A reduction in contaminant concentrations from the first sampling event was noted, however additional monitoring is needed to conclude that it is a drilling artifact • Figures 5 and 6 indicate a previously inverse relationship between groundwater elevation and contaminant concentrations in wells MW-9 and MW-5, respectively These two parameters have demonstrated parallel slopes for recent events In Figure 5, the inverse trend was consistent for well MW-9 for the first four monitoring events, but since the March 2001 event the relationship has been parallel • Figure 7 indicates an inconsistent relationship between groundwater elevation and contaminant concentrations in well MW-6 The relationship has been direct for the last two events In Figure 6, the inverse trend was constant for MW-5 for the first five monitoring events, but since the January 2001 event the relationship has been parallel o Wells MW-4, MW-5 and MW-9 contained 58, 560 and 800 ug/l 1,2 DCA, respectively for the previous event These wells did not contain 1,2 DCA for this event above detection limits It is noted that these wells contain elevated levels of TPH-G and therefore detection limits for 1,2 DCA were elevated 9 Well MW-5 and MW-9 contained 7 and 88-ug/l ethanol, respectively