The U.S. Army Corps of Engineers (USACE), Baltimore District is studying ways to improve the property formerly used by the Department of Defense in the 1950s, previously known as the Manassas Air Force Communications Facility (MAFCF). The area is now the southern portion of the Prince William County Public Schools property located in Independent Hill, VA. USACE is initiating a remedial design (RD) for remedial action (RA) to cleanup groundwater contamination associated with past military activity (see Site History below).
In August 2013, USACE completed a risk assessment to determine if remaining contaminants from past government use posed any hazards. The assessment showed there are no risks from site contaminants to students and staff in the northern part of the site where the Independence Nontraditional School is located (presentation slide 11).
However, elevated concentrations of contaminants (presentation slide 12) were detected in groundwater in the southern portion of the site. It is important to clarify this groundwater is not used for drinking water and there is no direct pathway between the public and the contaminated groundwater. This groundwater contamination could affect construction workers under very specific circumstances. A worker would have to spend four hours a day, 125 days a year, for a year working in a very confined trench to potentially experience any health risks.
USACE conducted a supplemental site characterization from 2015 to 2018 to help outline the best course of action to clean up the remaining groundwater contamination in the southern part of the site. Using the results from this investigation, USACE developed remedial alternatives to remediate the groundwater at MAFCF (presentation slide 14).
USACE, in coordination with the Virginia Department of Environmental Quality, will treat the contaminated groundwater to reduce future risks. This is to be done through a combination of in situ chemical oxidation (ISCO) and in situ enhanced bioremediation (ISEB) to address the contamination in the groundwater. This is to be completed by injecting materials into the groundwater that will treat the contamination. Within nested/flush mounted groundwater wells onsite, ISCO would be used to treat the source areas by injecting chemical oxidants into the bulk of the contamination. ISEB would subsequently be used to treat groundwater contamination further away from the source area by injecting natural materials to promote environmental conditions necessary for biodegradation of contaminants.