Laserfiche WebLink
of the aquifer materials, and shallow hydraulic gradient in the vicinity of the site, <br /> ' there appears to have been no migration of the contaminant plume away from the <br /> Langston property. <br /> ' 7 Since the areal extent of the hydrocarbon contamination in theg roundwater has not <br /> been found, additional drilling and monitoring would be required for complete <br /> ' definition <br /> ' Because of the potential for off-site contamination, and the location of several public and <br /> private water production wells within a 1/2-mile radius of the site, Murray & Associates, <br /> recommends the immediate removal and on-site treatment of the near-surface <br /> contaminated soil, the removal and disposal of the remaining piping associated with the <br /> former underground tanks, and the installation, development and sampling of two <br /> additional groundwater monitoring wells to thoroughly define the lateral extent of the <br /> ' groundwater contamination <br /> A program for the treatment of the contaminated groundwater should be postponed until <br /> the additional monitoring wells have been installed, the lateral extent of groundwater <br /> 1 contamination defined, and the contaminated soil removed. It is recommended however, <br /> that monitoring of water levels, and contaminant concentrations in the existing wells be <br /> implemented on a monthly/bimonthly basis to monitor potential changes in the direction <br /> of groundwater flow, and to evaluate the potential for off-site migration of the contaminant <br /> plume Finally, it is recommended that if migration of the contaminant plume reached the <br />' property boundaries, a groundwater extraction well be installed to capture the leading ading edge <br /> of the plume to prevent further migration <br /> Specifically this program should include <br /> 1 Groundwater level measurements on a monthly basis, with sampling of the four <br /> existing groundwater monitoring wells and analysis of water samples collected for <br /> BTEX and TPH-g on a bimonthly basis for a period of six months, or until <br /> groundwater remediation is complete <br /> 5 <br />