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T__ Ripona Market Quarterly Groundwater Sampling Report July 2002 Page: 2 table was present approximately 1 foot feet lower than in the July 2001 monitoring event A hydrograph of the groundwater elevations at the Ripona Market site is presented in Figure 6 Groundwater flow direction July 19, 2002 was North 86 East with a gradient of 0 008 ft/ft The potentiometnc surface and groundwater flow direction are shown on Figure 2 Site Map / Groundwater Flow This is a shift in groundwater flow and gradient from North 41 East / 0 02 ftlft observed in July 2001 but similar the July 2000 flow of North 80 East/ 0 009 Groundwater Elevations 7-19-02 Well Collar Elevation DTW GW Elevation MW-1 6958 2471 4487 MW-2 7001 2513 4488 MW-3 70 2535 4465 The analytical laboratory reported non-detectable concentrations of all contaminates in all of the wells except for MTBE, which was detected in two of the samples Groundwater chemistry for the July 2002 event is presented in Figure 3 MTBE was reported at a concentration of 23,280 ug/l in well MW2, an increase of 20,000 ug/l over the July 2002 . monitoring event MTBE was also reported in well MW3 at a concentration of 3 9 ug/l, a slight decrease from the July 2001 monitoring event MTBE distribution for the July 2002 event is shown in Figure 4 Methanol was not detected in any of the wells and does not appear to be present at the site The absence of all petroleum hydrocarbons and aromatic compounds suggests that the contaminants are being preferentially reduced through natural attenuation The dissolved oxygen distribution shows extremely low concentrations (2 0 — 3 0 mg/l) the vicinity of the MTBE and previous petroleum hydrocarbon contamination in comparison to the high concentrations detected in well MW 1 (8 4 mg/1) The reduced oxygen in the source area is indicative of biologic activity and suggests that active contaminate reduction is taking place Laborato Groundwater Sample Results Petroleum Compounds 07-19-2002 Sample I D Gasoline I Benzene I Toluene E-Benzene I Xylenes I MTBE I t-Butanol I TAME I METH 02 MW-1 <05 <0 3 <0 3 <0 3 <0 6 <1 0 <20 <1 0 <5 0 84 MW-2 <05 <0 3 <0 3 <0 3 <0 6 23280 113 10 <5 0 32 MW-3 <05 <0 3 <0 3 <0 3 <0 6 39 <20 <1 0 <5 0 2 0 ND=Non Detect NA=Not Analyzed Mg/L for gasoline&Methanol µg/L for BTEX,MTBE,and 8260 Oxygenated Compounds Gasoline, gasoline constituents, and methanol were not detected in any of the three • monitoring wells MTBE was detected in two wells at concentrations that exceed