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Mr Chuck Carmel . August 15, 1994 Page 2 Prior to sampling, the wells were purged of a minimum of three well volumes or until evacuated using a centrifugal pump or bailer After purging, each well was sampled using a Teflon bailer that was steam-cleaned between uses All groundwater samples were analyzed for total petroleum hydrocarbons as gasoline (TPH-G), and for benzene, toluene, ethylbenzene, and xylenes (BTEX) by U S Environmental Protection Agency (EPA) Method 503018020, and 8015 Modified Groundwater data sheets and the chain-of-custody form are included in Exhibit A GTI's groundwater sampling protocol is included as Attachment A in Exhibit A Results The general groundwater flow beneath the site on February 17, 1994, was to the northwest under an average hydraulic gradient of 0 002 (Figure 1) A summary of depth-to-water measurements and calculated groundwater elevations is presented in Table 1 Table 2 lists past and present groundwater flow directions and hydraulic gradients for this site Analytical results of groundwater samples are summarized in Table 3 The complete laboratory report for the sampling event is presented in Exhibit A Figure 2 shows TPH-G and BTEX concentrations for this sampling event Benzene concentrations ranged from nondetectabie in several wells to 200 micrograms per liter (µg/1) in ATR-3 TPH-G concentrations ranged from nondetectable in several wells to 1,900 µg/1 in well ATR-3 The detection limits for benzene, toluene, and ethylbenzene are 0 3 µg/1, for xylenes is 0 5 pg/l, and for TPH-G is 50 pg/l Approximately 0 14 feet of free product was measured in ATR-8 Discussion Water level elevations increased an average of 0 39 feet across the site since October 27, 1993 The water level in ATR-8 rose 1 13 feet since October 27, 1993 The northwesterly groundwater flow direction and the hydraulic gradient (0 002) are consistent with previously reported data One or more of the BTEX constituents were detected in the samples from wells ATR-1, 2, 9, 10, 11, and 12 at concentrations less than or equal to 1 µg/1 This is the fust quarter that BTEX have been identified in samples from these wells, with the exception of 0 7 pg/l xylenes in ATR-9 last quarter However, the trip blank also contained low levels of toluene Use or disclosure of data contained on this sheet is subject to the restriction specified at the beginning of this document 1264\REP0RTS11ST944QTR RPT