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Mr Mike Infurna Page 2 groundwater in C Zone well MW11) was 63 51 feet btoc Since previously measured on June 9, 2004 water levels fell an average of 4 38 feet in the A zone wells, 6 86 feet in the B zone wells, and 6 88 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 August 30, 2004, the potentiometric surface of the A Zone wells ranged from 39 95 feet to 44 02 feet below mean sea level (MSL) The potentiometric surface of the B Zone wells ranged from 43 86 feet to 44 17 feet below MSL The potentiometric surface in C Zone well MW11) was 44 05 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 Flow is toward the west-southwest at a gradient of approximately 0 09 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 west-southwest at a gradient of approximately 0 14 ft/ft while flow in the B Zone is toward the west-northwest at approximately 0 001 ft/ft Groundwater Sampling On August 30 and 31, 2004, the site wells were purged and sampled 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, except wells 3 and 4, which went dry The samples had to be taken from the first bailer pulled 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 8015B GROUNDWATER ANALYTICAL RESULTS TPHg and BTEX compounds were not detected in the samples from wells MW5, MW7 and MW1D TPHg was detected in the samples from the rest of the wells at concentrations ranging from 430 parts per billion (ppb) in MW3 to 92,000 ppb in MW1 Benzene levels in these wells ranged from <0 5 ppb in MW3 to 12,000 ppb in well MW1 Analytical results are summarized in Table 2 Attachment B contains laboratory reports and chain of custody documentation Gasoline oxygenates and additives were not detected in wells MW3 and MW7 1,2-DCA was detected in each of the other wells at concentrations ranging from 4 7 ppb in MW5 to 2,300 ppb \\GZA_FSIVOL 11DATA1GROUNDZEIHARRYS\Reports\QMR1200413QM2004a doc