ARCHIVED REPORTS_XR0012019 - Laserfiche WebLink

Home Browse Search

i Ms Margaret Lagono ' Page 2 of 5 • ' Water levels at the site fell approximately 1 68 feet since last monitored in May 2001 The potentiometnc surface was above the top of the screened intervals in all wells except monitoring wells MW2, MW13 and MW14 and vapor wells VW2, VW5 and VW6 Groundwater flowed in ' an easterly direction, and the average gradient was approximately 0 004 feet per foot A groundwater gradient map generated using the monitoring data from all site wells is shown on ' Figure 2 Groundwater monitoring data are summarized in Table 1 Monitoring logs are included in Attachment A ' On August 29, 2001 through August 30, 2001, a Ground Zero technician collected groundwater samples from groundwater monitoring wells monitoring wells MW1 through MWS, MW7, MW8, MW9, MW 12 and MW 14 and vapor wells VW 1 and VW3 A minimum of three well casing ' volumes was purged from each well prior to sampling During the purging process, physical parameters (pH, conductivity, and temperature) were monitored in each well and allowed to stabilize before collecting groundwater samples Samples were collected after a minimum of 80% ' recovery of initial depth to groundwater measurements Purge water was contained in labeled 55- gallon drums approved by the Department of Transportation (DOT), which are stored onsite within a secured area Purge logs are included in Attachment A I ' Samples collected for analysis were placed in an iced cooler and transported under chain of • custody to Argon Laboratories (FLAP #2359) Analysis consisted of gasoline oxygenates, EDB, ' 1,2 DCA by EPA Method 8260, TPHg by EPA Method 8015 modified and BTEX by EPA Method 8020 ' GROUNDWATER ANALYTICAL RESULTS Groundwater Monitoring Wells ' TPHg was detected in all sampled wells except MW7, MW9 and MW 12, and benzene was detected in all sampled wells except MW1, MW7, MW9 and MW12 Concentrations of TPHg and BTEX decreased in each well relative to the concentrations present during the previous ' sampling event Overall, the extent of the plume of groundwater contamination associated with the onsite release is stable and concentrations are decreasing TPHg and BTEX concentrations ' are summarized in Table 2 Attachment B contains laboratory reports and chain of custody documentation Graphs depicting TPHg and benzene concentrations over time are included in Attachment C ' MTBE was detected in wells located along the southern portion of the property (MW3, MW4, MW7, MW 12 and MW 14), and in well MW9 located offsite along the north side of Market ' Street These wells are affected by offsite releases EDB was not detected in any monitoring wells sampled, however, 1,2 DCA was present in monitoring wells MW2 and MW 12 Analytical results for gasoline oxygenates, EDB and 1,2 DCA are summarized in Table 3 Attachment B contains laboratory reports and chain of custody documentation � ' rwklgmr<3QM2W1