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M' . 3.0 RESULTS 3.1 Depth to Groundwater and Groundwater Flow Direction The depth to groundwater on June 9 was approximately 30 feet below grade (Table 1,) This depth is approximately 3 feet more than in April, and 2 5 feet greater than a year ago Using the 3-point method to contour these values yields a groundwater elevation (piezometric surface) map with a uniform gradient of 0 0049 ft/ft sloping to the southeast (Figure 3) Except in the first quarter of 2003 and the first quarter of 2004, flow has consistently been to the southeast 3.2 Laboratory Results Because it is the least contaminated, well JLM-4 is the first well to be purged and sampled each quarter, in order to avoid the possibility of cross-contamination from one of the other wells Therefore, any detection of hydrocarbons in this well should be representative of true conditions Total Petroleum Hydrocarbon and BTEX concentrations continue to be below the detection limit in JLM-4, but 1,2-DCA has been present at low concentrations (1-3 ppb) in most quarters (Table 2) The gasoline oxygenate MTBE was first detected in the well in the fourth quarter of 2003, and has now been detected for three consecutive quarters TBA was first detected in the first quarter of 2004, and it was again detected this quarter(46 ppb) In addition, DIPS was detected for the first time at a concentration of 1 ppb Hence, the data from this quarter apparently confirm the suggestion in the First Quarter 2004 Report that gasoline oxygenates have migrated to this well since the third quarter of 2003 Oxygenate and lead scavenger concentrations in JLM-3 and JLM-5 again remained constant this quarter In JLM-3, the TPH-g concentration declined and the TPH-d concentration rose In addition, both benzene and ethylbenzene dropped below the detection limit In JLM-5,the TPH-g and TPH-d concentrations were slightly higher than last quarter, but the differences are not statistically significant The biggest change was in ethylbenzene, which dropped from 120 ppb to less than 0 5 ppb 4.0 CONCLUSIONS AND RECOMMENDATIONS In the Fourth Quarter 2003 Monitoring Report we observed that concentrations have declined in both JLM-3 and JLM-5 over time, this is illustrated in Figure 4 The declines have not been steady, but the trend lines shown indicate that there has been some reduction in the concentrations of TPH-g and BTEX Gasoline oxygenates and lead scavengers, however, have remained largely unchanged throughout the past two years In contrast, there has been a recent rise in oxygenate concentrations in JLM-4 Because there has been no corresponding change (decline) in the oxygenate concentrations in JLM-3 and JLM-5, the increases in JLM-4 could not be due to migration of oxygenate compounds away from JLM-3 and JLM-5 toward JLM-4 Instead, the data show rather clearly that the plume of oxygenates (and all other hydrocarbons) is stable in the vicinity of JLM-3 and JLM-5 Therefore, the increase in oxygenate concentrations in JLM-4 is more likely due to desorption from soil in the immediate vicinity of JLM-4 Hydrocarbon 3