ARCHIVED REPORTS_XR0007262 - Laserfiche WebLink

Home Browse Search

Mr Mike lnfurna Page 2 MW1D was 52 58 btoc 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 March 18, the potentiometric surface of the A Zone wells ranged from 33 03 feet to 33 09 feet below mean sea level (MSL) The potentiometric surface of the B Zone wells ranged from 33 03 feet to 33 14 feet below MSL The potentiometric surface in C Zone well MW1D was 33 12 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 south-southwest at a gradient of approximately 0 0006 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 toward the east and southeast at a gradient of approximately 0 001 ft/ft while flow in the B Zone is toward the southwest at approximately 0 0004 ft/ft Groundwater Sampling On March 18 and 19, 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 Purgewater 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 MWS and MW7 TPHg was detected in the samples from the rest of the wells at concentrations ranging from 85 to 93,000 parts per billion (ppb) Benzene levels in these wells ranged from c 0 5 ppb in MW3 to 10,000 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 MW1D, MW3, and MW7 1,2- DCA was detected in each of the other wells at concentrations ranging from 2 7 ppb (MW5) to 770 ppb (MW1) No other oxygenates or additives were detected Analytical results for oxygenates and additives are summarized in Table 3 Attachment B contains laboratory reports and chain of custody documentation 11GZA—FSIVOL-11DATAIGROUNDZEIHARRYSIReports\QMR11QM2004a doe