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h ,r 13 April 1998 AGE-NC Project No 95-0143 Page 3 of 4 ppb Styrene was detected in MW-9 at a concentration of 54 ppb, below the MCL of 100 ppb BTE&X were detected by EPA Method 8260 at concentrations similar to EPA Method 602 Eight additional constituents without established drinking water standards were detected by EPA Method 8260 in samples collected during the February 1998 monitoring event (Table 3) Petroleum hydrocarbons were not detected in the samples collected from MW-10, MW-15, MW-16 or MW-17 Free product was not encountered in any of the wells on the site Analytical results of ground water samples are summarized on Tables 2 and 3 The laboratory report (MAI Laboratory I D Nos 85664 - 85672) and chain-of-custody for nns ai e included in Appendix B 40 SUMMARY/CONCLUSIONS Based upon data collected from the site, AGE concludes • Ground water elevation increased an average of nearly three feet between November 1997 and February 1998 The nnfened ground water flow direction remains toNvards the north to • northeast at the site • Petroleum hydrocarbons were not detected in wells MW-10, MW-15, MW-16 and MW-17, defining the lateral extent of impacted gi ound water towai d the south east and north • TPH-g, BTE&X, 1,2-DCA, sec-butylbenzene, isopropylbenzene and naphthalene were detected in the sample collected from MW-14 during the February 1998 monitoring event Detection of these constituent innay indicate the leading edge of a hydl ocai bon plume 11 is not clear weather the constituents detected in MW-14 originate from thy; subject property or from the Crystal Cieam and Butter Company site, located immediately vvest of the subject pr Opel ty • Free product was not encountered at the site during the February monitorijig event Howevei, ground water is above the screened interval in MW-3 which could prevent the detection of free product, if present • Monitoring wells MW-3 and MW-9 ale the most intensely impacted wells despite also having the thickest saturated zone above the well screens • Between November 1997 and February 1998, petroleu ri hydrocarbon concentrations remained generally stable at the site In general, hydrocarbon concentrations have followed a fluctuating, poorly defined trend since quarterly monitoring began Adiance(/GroEmironmental,Inc