Laserfiche WebLink
' 7.0 DISCUSSION <br /> ' Groundwater was encountered in all 3 aquifers during drilling. The installation of a double- <br /> cased well prevents influence from the A- and B-aquifers on the water quality of the C-aquifer <br /> ' well. <br /> ' The groundwater sample from monitoring well C1 contained no laboratory detectable <br /> concentrations of trichloroethene. TCE has been detected in the C-aquifer in groundwater <br /> samples from the 517C monitoring well, adjacent to the railroad tracks to the east of the subject <br /> ' site, at concentrations ranging from 5 to 13 micrograms per liter (ug/1). These monitoring wells <br /> are owned and being monitored by the Sharpe army depot. <br /> ' The detected concentration oftrichloroethene (3 ug/L) in the monitoring well development water <br /> is below the laboratory reporting limit of 5 ug/L. The detected presence of TCE in the <br /> ' development water has several possible explanations. The laboratory result may be in error, <br /> as the small quantity detected is below the laboratory reporting limit of 5 ug/I. Residual drilling <br /> mud in the well, which was removed from the well during development, could have been <br /> contamination from the overlying aquifers. <br /> ' The sands from the drilling fluid were disposed at Rancho Los Lobos Landfill in San Ardo, <br /> California. The development and purge groundwater was discharged to the onsite storm water <br /> containment pond after permission was received from Mr. James Taylor at the Regional Water <br /> ' Quality Control Board. <br /> ' 8.0 RECOMMENDATIONS <br /> TRC recommends that the groundwater be sampled on a quarterly, or other regular basis, to <br /> ' determine if contamination from the Sharpe army depot has migrated and impacted the <br /> groundwater quality at the site. <br /> 1 <br /> 1 <br /> ' 14744003.013 5 <br /> TRC <br />