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detected in KF-2 was MTBE, at a concentration of 0.97 ppb. Lead was not detected in any of the wells. After rising during the fourth quarter of 2001, TPH-g and BTEX concentrations in KF-3 resumed their decline, and concentrations of all analytes were at least 50% lower than in the fourth quarter. The TPH-g concentration of 280 ppb and the benzene concentration of 39 ppb represent 99% declines from their peak concentrations in August of 1997. The MTBE concentration of 66 ppb suggests that the previously reported concentration of 140 ppb in November was excessive, due to the inaccuracy of EPA method 8020. Examination of Table 2 illustrates that two out of three times, analysis by method 8020 has yielded a result that is 2-4 times greater than that detected using the more accurate method 8260. Tertiary-amyl-methyl ether (TAME) and tertiary-butanol (TBA) were also detected in KF-3, at concentrations of 0.51 and 28 ppb. This is the first time that the laboratory has achieved reporting limits of 2 ppb and 100 ppb, respectively, and consequently this is the first time these hydrocarbons have been detected. After falling below the reporting limits in the fourth quarter of 2001, concentrations of some analytes increased in KF-5 during the first quarter of 2002. Gasoline was detected at 190 ppb, benzene was detected at 41 ppb, and xylene was detected at 0.65 ppb. In addition, MTBE, TBA, and 1,2-DCA were also detected at relatively low concentrations in this well. Benzene concentrations are plotted against time in Figure 5 for those wells in which it has been detected. The maximum concentration limit (MCL) for benzene (1 ppb) is also shown for reference. Concentrations in the three original. wells (KF-1, 2, and 3) were greater than 1,000 ppb when monitoring began in late 1994 and remained'high through 1997, but began falling in early 1998. This fall was coincident•with a rise in the water table (Table 1). Concentrations rose again in early 1999, but have since fallen in two of the three wells to below the reporting limit. During that time, the depth to groundwater oscillated between 6 and I1 feet below grade, and the decline in hydrocarbon concentrations did not correlate with the changes in water depth. 4.4 Hydrocarbon Plume Maps As requested by PHS/EHD, the February 2002 laboratory data from the Chevron site were obtained from Gettler-Ryan, and contour maps of TPH-g, total BTEX, and MTBE were constructed (Figures 6-8). The TPH-g and Total BTEX snaps depict two partially separated plumes, centered in the vicinity of Chevrons MW-1 and MW-4, with a less-contaminated area in the center of that site between these "hot spots". The plume around MW-1 is larger than that around MW-4, and extends east of the site under Franklin Street and encroaches on the southwestern corner of the Kwikee site. There is a strong eastward concentration gradient, and concentrations decrease rapidly east of MW_ 1, as illustrated in Figure 9. The map of MTBE is somewhat different. MTBE was not detected in MW-4 at the Chevron site, because interference from other hydrocarbons masked its presence and the detection limit was 5