ARCHIVED REPORTS_XR0010461 - Laserfiche WebLink

Home Browse Search

r YA v T C A S S O C I A T E S I N C levels ranged from 69 92 to 74 63 feet below the tops of the well casing elevations The water level data were used to develop the groundwater elevation contour map (Figure 4) Assuming horizontal isotropic conditions, groundwater flow in the uppermost aquifer beneath the site on May 23, 2003 varied across the site, but in general, the flow was southeasterly The average hydraulic gradient was calculated to be 0 03 ft/ft or approximately 139 ft/mile A summary of groundwater monitoring data is presented in Table 1 ANALYTICAL RESULTS The groundwater samples collected from wells MW1, MW2, MW4, MW6, and MW9 and contained detectable concentrations of TPHg and BTEX constituents The groundwater samples collected from MW5 contained detectable concentrations of TPHg but contained no THPd or BTEX The groundwater samples collected from wells MW3, MW8, the on-site domestic well and Phillips domestic well contained no detectable concentrations of TPHg, TPHd, or BTEX The groundwater sample collected from well MW6 contained the highest concentration of MTBE The groundwater samples from wells MW 1 and MW5 contained detectable concentrations of MTBE The groundwater samples collected from wells MW2, MW3, MW4, MW8, and MW9 contained no detectable concentrations of MTBE although the reporting limits from MW2 were elevated due to dilution factors The groundwater samples from wells MW1, MW3, MW5, MW6, and MW9 contained detectable concentrations of 1,2-DCA The groundwater samples from MWI and MW6 contained detectable concentrations of TBA The groundwater samples collected from wells MW2, MW4, MW8, MW 10, the onsite domestic well and Phillips domestic well did not contain detectable concentrations of ETBE, DIPE, TAME, 1,2-DCA, and EDB Analytical results of groundwater samples are summarized in Table 2 and laboratory data sheets are contained in Attachment 2 ADDITIONAL SITE ACTIVITIES On June 25, 2003, ATC personnel attempted to remove the obstruction from well MW10 ATC probed the obstruction with a metal rod in an attempt to clear the obstruction ATC also infected clean,water in to the well with a garden hose These efforts were unable to clear the obstruction CONCLUSIONS The highest concentrations of TPHg and BTEX were detected in the groundwater sample from well MW2 The highest concentrations of MTBE and 1,2-DCA were detected in MW6 The direction of groundwater flow is to the southeast S lEnviromental1252911reportsl2QR-2003 doc 3