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Mr. James Barton September 3, 2008 Page 3 of 4 The water samples were decanted into the appropriate containers, placed in an ice chest cooled to a temperature of approximately 4° Centigrade and submitted to Argon Laboratory (ELAP No. 2359) under chain of custody protocol for analysis. The sample from MW3 was analyzed for TPHg, TPHd, TPHk and TPHmo using EPA Method 8015M; for BTEX by EPA Method 8021B; and for fuel oxygenates and additives by EPA Method 8260B. As per EHD directive, samples from wells MWI, MW2 and MW4 were analyzed only for TPHg, TPHmo, BTEX, oxygenates and additives since TPHd and TPHk were not detected in the sample from MW3. 3.0 GROUNDWATER ANALYTICAL RESULTS No petroleum hydrocarbons or gasoline additives were detected above method detection limits in groundwater samples collected from any site well, except well MW3. Well MW3 contained TPHmo at a concentration of 520 micrograms per liter (µg/L), TPHg at 460 µg/L, benzene at 8.2 µg/L, toluene at 2.4 µg/L, ethylbenzene at 5.8 µg/L,xylenes at 14 µg/L, MTBE at 0.6 n/L and 1,2-DCA at 1.6 gg/L. Groundwater analytical results are summarized in Table 2. Attachment B contains laboratory reports and chain of custody documentation. 4.0 CONCLUSIONS Although low levels of dissolved petroleum hydrocarbon constituents remain in well MW3, no petroleum hydrocarbon constituents have been detected in groundwater from any other site well. The removal of free-phase product from well MW3 through periodic bailing (September 2001 —April 2003), a passive hydrophobic skimmer (May 2003 — April 2005), and an active belt skimmer (April 2005 — May 2006) resulted in a considerable reduction of dissolved petroleum concentrations. Among the petroleum hydrocarbon constituents, only benzene (8.2 gg/L) and 1.2-DCA (1.6 µg/L) exceed their respective Maximum Contaminant Levels (MCLS) established by the Department of Health Services. The MCL for benzene is 1.0 µg/L and the MCL for 1,2-DCA is 0.5 µg/L. Ground Zero feels that the subject petroleum hydrocarbon leak case is a candidate for closure as a low- risk contamination case based upon the following: • Petroleum hydrocarbon constituents in groundwater have been reduced by 85% or more in the source area; • Benzene was detected at only 8.2 gg/L in groundwater collected from well MW3 in August 2008; 1,2-DCA was present in this well at a level of only 1.6pg/L and no other petroleum hydrocarbon constituent was present at a concentration above its respective MCL; • No petroleum hydrocarbon constituents have been detected in any other site well, an indication that the lateral extent of contamination associated with the waste oil release is limited to a small area near the former UST; • The vertical extent of contamination in soil has been defined. Soil samples collected at a depth of 30-31 feet were non-detect for all constituents of concern except for boring SB3 where all analytes were non-detect at a depth of 36 feet. G:\GROUNDZMGABBARD\reports\QMR\2008\3QM2008.doc