The U.S. Environmental Protection Agency (EPA) issued a record of decision (ROD) in 2001 (EPA, 2001) directing remediation of the site via multiple remedies. A pump-and-treat (P&T) system was constructed in 2003 - 2004, and began operation in 2005. In 2006, the EPA issued an explanation of significant differences (ESD) (EPA, 2006), which …show more content…
The information presented in the 2013 MNA evaluation confirmed the findings of the 2005 MNA evaluation that TCE contamination in the eastern-downgradient portion of the TCE plume and not captured by the P&T system would naturally attenuate to concentrations below the 5 micrograms per liter (µg/L) remedial goal specified in the ROD before the plume reaches the groundwater use restriction boundary. The 2013 report also concluded that site-related TCE present in the central and western-upgradient portions of the plume will also naturally attenuate below the 5 µg/L remedial goal, even if the P&T system is shut …show more content…
· Cease P&T operations by decommissioning the air stripper treatment plant and the extraction and injection wells.
The groundwater use restriction and groundwater monitoring and reporting components of the current remedy are unchanged. Groundwater monitoring will provide the information necessary to confirm the effectiveness of MNA as a sitewide remedy.
The groundwater remedy presented in this ROD amendment addresses the remaining portions of the site-related TCE plume by monitoring the groundwater to verify that contaminant of concern concentrations are reduced, through natural attenuation, to concentrations below the remedial goals specified in the ROD, before reaching the groundwater use restriction boundary.
The primary outcome of this ROD amendment is restoration of the aquifer to its highest beneficial use, within a timeframe that is reasonable based on expectations of current and future groundwater use.
Statutory