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Mr Mike Infurna Page 2 • groundwater in C Zone well MW1D was 49 39 feet btoc Since previously measured on August 29, 2005, water levels rose an average of 9 07 feet in the A Zone wells, 9 05 feet in the B Zone wells, and 9 18 feet in the C Zone well Water level data are summarized in Table 1 Monitoring well locations are shown on Figure 2 Field data sheets are included in Attachment A Groundwater elevation was determined in each well by subtracting the depth to groundwater measurement from the respective surveyed wellhead elevation On December 28, 2005, the potentiometric surface of the A Zone wells ranged from 29 95 feet to 30 03 feet below mean sea level (MSL) The potentiometrzc surface of the B Zone wells ranged from 29 97 feet to 30 14 feet below MSL The potentiometrnc surface in C Zone well MW1D was 29 93 feet below MSL Due to the complexity of the well depth/potentiometric surface relationship, groundwater gradient was interpreted in several ways Figure 3 interprets the gradient using data from the A and B Zone wells together Indicated flow is predominantly toward the southwest at a gradient that ranges from approximately 0 0005 ft/ft to 0 0012 ft/ft Potentiometric surface maps utilizing data from the A and B Zones separately are depicted on Figures 4 and 5, respectively Flow in the A Zone is interpreted to be toward the southeast and flow in the B zone is interpreted to be toward the southwest, both at a gradient of approximately 0 001 ft/ft Groundwater Sampling On December 28 2005, the site wells were purged and sampled Well UHMW7 was not sampled • during the fourth quarter During purging, temperature, pH and electrical conductivity parameters were measured Purging continued until these parameters had stabilized A minimum of three well casing volumes was purged from each well Purge water was contained in appropriately labeled DOT-approved 55-gallon drums Purge logs are included in Attachment A Groundwater samples were collected after adequate groundwater recovery Samples were collected in sealed, preserved VOAs and stored in an ice chest refrigerated to a temperature of approximately 4° C Samples were delivered under chain of custody protocol to Argon Laboratories (ELAP #2359) Sample analysis consisted of gasoline oxygenate additives, 1,2-DCA and EDB using EPA Method 8260B, BTEX using EPA Method 8021B, and TPHg using modified EPA Method 8015M GROUNDWATER ANALYTICAL RESULTS TPHg and BTEX compounds were not detected in the samples collected from wells MW5, MW6, MW7 and MW1D TPHg was detected in the samples collected from the remaining site wells at concentrations ranging from 180 parts per billion (ppb) in MW3 to 55,000 ppb in MW1 Benzene and xylenes were not detected to well MW3, and benzene was not detected in well MW4 Benzene was detected in wells MW1 and MW2 at concentrations of 4,900 ppb and 520 ppb, respectively Analytical results are summarized in Table 2 Attachment B contains laboratory reports and chain of custody documentation • EDB was not detected in any well The gasoline additive 1,2-DCA was not detected in wells G\GROUNDZEIHARRYS1Reports\QMR1200514QM2005a doc