Hidden Lane Landfill
Current Site Information
EPA Region 3 (Mid-Atlantic)45470 Persimmon Lane
Sterling, Loudoun County, VA 20165
EPA ID# VAD980829030
10th Congressional District
Last Update: February 2015
Other NamesLoudoun Dump
Current Site Status
EPA completed the Remedial Investigation at the Hidden Lane Landfill Site in January 2015.
EPA is currently conducting a Treatability Study at the Site to determine the effectiveness of treating the TCE-contaminated groundwater in placed or “in-situ.” EPA expects results from this study later this year.
EPA conducted sampling for possible vapor intrusion at the Site during January and February 2015 to determine if TCE was entering buildings from the subsurface as a gas. EPA expects final results on those samples sometime this spring.
Site DescriptionThe Hidden Lane Landfill was a 25-acre privately owned and operated disposal facility north of Virginia Route 7 between the Broad Run Farms and Countryside communities. It is immediately adjacent to the floodplain of the Potomac River. Starting in 1971 the facility accepted a variety of solid wastes including construction and demolition wastes, land clearing wastes and other items such as appliances, tires, paper, and cardboard. The county closed down the facility in 1984, pursuant to a local court decision the year before. The Hidden Lane Landfill had been named by county and state health officials as the likely source of the degreasing solvent trichloroethylene, first detected in drinking water wells of some homes in the Broad Run Farms subdivision just west of the landfill in 1989.
Site ResponsibilityThe Loudoun County Department of Health and the Virginia Department of Environmental Quality have been the key agencies addressing the contamination issues at the site up until now. Since the site has been added to the National Priorities List, the EPA has taken the lead and continues to work with these other agencies at resolving the environmental and health risks at the site.
NPL Listing HistoryOn September 19, 2007 the EPA proposed to add the site to the NPL. The Site was listed on the NPL on March 19, 2008.
Threats and ContaminantsThe contaminant of the concern at the site is trichloroethylene (TCE).
Contaminant descriptions and risk factors are available from the Agency for Toxic Substances and Disease Registry, an arm of the CDC.
The Loudoun County Department of Health collected 67 samples from private wells in the Broad Run Farms area, searching for trichloroethylene (TCE) and other contaminants. The community to the east, Countryside, was not sampled because the homes in that subdivision use public drinking water. Data results indicated that 22 homes had TCE in their private wells; of those,16 were above safe drinking water levels. Funds from the Virginia Environmental Emergency Fund were used to install a total of 26 whole house carbon filtration units for homes that had detectable levels of TCE in their wells. The DEQ also performed more than two years of operation and maintenance on the filtration units, including several rounds of sampling to ensure that the units are working properly. EPA assumed responsibility for these systems from VDEQ on July 1, 2008 and has offered support for several other property owners who chose to install such systems on their own. EPA continues to test these systems quarterly and maintain them to ensure they are operating properly.
EPA began conducting the remedial investigation at the Site in December 2008 with sampling and maintenance of the landfill gas monitoring system. No significant detections of landfill gas have been recorded since sampling began.
Initial field work for the groundwater investigation began in January 2009. The first stage of monitoring well drilling and installation was completed in late Spring 2009. EPA completed its first round of surface water sampling in early Summer 2009 and two rounds of groundwater (well) sampling in late 2009. EPA evaluated those results and concluded that a series of nine deeper monitoring wells needed to be installed to 350 feet below ground surface (bgs) to better characterize the groundwater contamination. EPA began installing those deeper wells in late summer 2010 and completed the work, including sampling and analysis, in 2011.
As a result, EPA believes it has a much better picture of the location of the TCE-contaminated groundwater plume, but still needs to confirm the depth and direction of the plume below ground. To accomplish this, EPA began deepening three of the nine wells installed in 2010-2011 to a depth of 500 feet bgs in January 2012 and finished that work this summer. EPA has confirmed that the plume moves generally north from the Landfill in the direction of the Potomac River.
EPA completed the human health risk assessment at the Site in 2013. EPA is currently finalizing the ecological risk assessment and has begun developing remedial alternatives to be evaluated during the Feasibility Study. EPA will use this information to develop a cleanup approach in 2014