The Corps of Engineers conducted an extensive soil investigation to determine the nature and extent of soil contamination within the Spring Valley Formerly Used Defense Site. As part of this effort 1,632 residential, federal/District of Columbia, and commercial properties/lots were sampled for arsenic.  The Corps of Engineers identified 178 properties/lots that required cleanup. The primary method of cleanup was through excavation of the arsenic‐contaminated soil.

As of February 2016, all properties in Spring Valley identified by the Corps for arsenic removal have now been remediated.

The Corps of Engineers conducted an investigation from 2004 to 2014 to determine to what extent American University Experiment Station-related activities may have impacted the groundwater within the Formerly Used Defense Site. The investigation involved the installation of monitoring wells and the collection of samples from the wells and additional surface water locations. To date, the Corps of Engineers has installed 53 wells and collected a number of surface water samples.

Perchlorate has been detected at levels above the EPA interim drinking water health advisory of 15 parts per billion (ppb) at two locations in the project area, with a highest detection level of 146 ppb identified on American University’s campus. As a reminder, Spring Valley groundwater is not currently used as a drinking water source, but for comparison purposes, groundwater contaminant concentrations are compared to drinking water standards and advisories established by the EPA. The Corps of Engineers is currently working on the Groundwater Remedial Investigation Report (RI). Once the team obtains Partner consensus and approval, the Groundwater RI report will be finalized and available to the public on this public webpage and the Information Repository at the Tenley-Friendship Branch Library, 4450 Wisconsin Ave. N.W., Washington, D.C.

The Corps of Engineers, in conjunction with the U.S. Environmental Protection Agency and District Department of the Environment, identified 101 residential properties with an increased likelihood of containing buried ordnance items. The Corps of Engineers safely completed this process at all identified residential properties as of December 2011, with the exception of one property where the Corps of Engineers was denied access by the property owner.

In addition to residential properties, the partners identified a 62‐acre area in the Dalecarlia Woods that was a former down range impact area. This ordnance investigation was safely completed in December 2011.

The Corps of Engineers identified and removed munitions and debris from four burial pits and several debris fields containing more than 1,000 ordnance items, including rounds filled with chemical agent. Two of the burial pits were located at 4801 Glenbrook Road and were investigated and cleaned up between March 1999 and March 2000.

A third burial pit straddled the area between 4801 and 4825 Glenbrook Road N.W.  The Corps of Engineers determined that the most thorough cleanup alternative for 4825 Glenbrook Road was to remove the house and clean it up to residential standards, providing for unrestricted future use of the property.  For more information on the 4825 Glenbrook Road project click here.