Record of Decision System (RODS)
DOVER AIR FORCE BASE
|Site Name:||DOVER AIR FORCE BASE|
|City & State:||DOVER DE 19901|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
|Contaminant:||Metals, PAH, PCBs, Pesticides, VOC|
Please note that the text in this document summarizes the Record of Decision for the purposes of facilitating searching and retrieving key text on the ROD. It is not the officially approved abstract drafted by the EPA Regional offices. Once EPA Headquarters receives the official abstract, this text will be replaced.
Dover Air Force Base (DAFB) is located in Kent County, Delaware, 3.5 miles southeast of the city of Dover and is bounded to the southwest by the St. Jones River. DAFB comprises approximately 4,000 acres of land, including annexes, easements, and leased property. The surrounding area is primarily cropland and wetlands.
DAFB began operation in December 1941. Since then, various military services have operated out of DAFB. The current host organization is the 436th Airlift Wing. Its mission is to provide global airlift capability, including transport of cargo, troops, equipment, and relief supplies.
Wastes generated by DAFB are directly related to activities supporting the various aircraft that have been stationed at the base over the years. DAFB was listed on the National Priorities List (NPL) in 1989.
OU1 addresses the contaminated soil and structures for the Fire Training Area 03 (FT03). OU6 addresses the groundwater at FT03 (see description of FT03 under OU6). A Record of Decision (ROD) was completed for OU1 in September 1990.
OU3 is the Oil/Water Separator at Building 918 (Site OT 40). Site OT 40 is located in the northeastern portion of DAFB. It was installed in 1959 to service Hangers 918 and 922 and is still in use. The hangars currently house heavy equipment for maintenance shops. Historically, these buildings were aircraft maintenance facilities. One of the two RODs completed in March 1995 addressed OU3.
OU4 is the Underground Storage Tank (UST) at Building 124 (Site WP 32). It is located in the southeastern portion of the industrial section of DAFB. It is a 1,000-gallon UST that received waste oil from the automobile hobby shop. The tank began receiving oil in 1969. In 1991, responsibility for disposal of the tank contents was transferred to the Defense Reutilization and Marketing Office (DRMO). Use of the tank continued until mid-1991, when an aboveground tank was installed to hold the waste oil. One of the two RODs completed in March 1995 addressed OU4.
OU5 is the Lindane Source Area of Area 6. A lindane groundwater plume emanates from the Paint Washout Area (Site SS59). Lindane is a nonvolatile pesticide compound. The lindane source is believed to reside in the subsurface soils of the open store yard in the Paint Washout Area. An interim remedial action for OU5 was presented in one of the four RODs issued in September 1995.
FT03 is 2 to 3 acres in size and is located in the northeast portion of DAFB. This site is the most recent location of fire training exercises at DAFB and was used between 1970 and 1989. Waste oils and non-specification fuels were ignited twice weekly for fire training activities. The controlled burn was contained within an area constructed of a 12-inch soil and gravel berm. A 2,000-gallon UST north of the training pit was used to store fuels for the training exercises. OU6 is the groundwater at FT03. One of the three RODs completed in September 1997 addressed OU6.
Landfill 18 (LF-18) is located within Area 9 of the South Management Unit. The South Management Unit s one of four Management Units into which the Base has been divided. Area 9, one of three associated areas identified in the South Management Unit, extends from approximately US Route 113 to the Golf Course Tributary and the Base boundary. LF18 is the site of a former landfill that underlies the DAFB golf course and is next to the Base boundary along the southern edge of Area 9. A ROD was completed in September 1996 that addressed LF-18.
Landfill 13 (LF13) is the location of an inactive surface landfill located in the eastern portion of the Base. The approximately 8-acre site is covered with small trees and underbrush and has a gravel road down the center. The area surrounding LF13 was delineated as a wetland, and portions are densely forested.
LF13 was used in the 1960s for the disposal of smallquantities of general refuse and large quantities of construction rubble. From the late 1960s to the early 1990s, the site primarily received construction rubble. Buried metal was indicated by ground-penetrating radar. The dumping of rubble over the edge of the site, with subsequent covering and grading of the slope, created a 15- to 20-foot mound on the former lowlands as the landfill was advanced toward the base boundary. At present, this site is inactive and is partially covered with lumber and construction rubble such as concrete, metal, scraps, and cans.
One of the three RODs completed in September 1997 addressed the soil and groundwater in LF13.
OU9 is comprised of Liquid Waste Disposal Area 14 (WP14) and Landfill 15 (LF15). WP14 is the site of a liquid waste disposal trench located in the northeast portion of the Base. WP14 was used in the 1950s for the disposal of waste solvents, hydraulic fluids, waste oils, and other liquid wastes. After disposal activities ended at this site, probably in the early 1960s, the trench was filled with 3 to 4 feet of local soil and seeded with grass. LF15 is the location of a former trenched landfill located 200 feet east of WP14. During the 1960s, this 2-acre area was reportedly used for the disposal of general refuse and small quantities of industrial shop wastes. When disposal activities ceased at an unknown date, the site was covered with several feet of local soil and seeded. One of the three RODs completed in September 1997 addresses the groundwater at WP14 and LF15.
OU10 is Target Area 1 of Area 6. Area 6 is defined by the associated of chlorinated solvents in groundwater forming a plume in the Columbian Aquifer. Target Area 1 is one of the four areas in Area 6 where shallow groundwater (i.e., the top ten feet of the Columbian Aquifer) contains chlorinated solvent plumes. Target Area 1 originates at the Paint Washout Area (SS59) and extends south approximately 800 feet between 8th and 9th Streets. Target Area 1 is approximately 5.2 acres in size. An interim remedial action for OU10 was presented in one of the four RODs issued in September 1995.
OU11 is Target Area 2 of Area 6. Area 6 is defined by the associated of chlorinated solvents in groundwater forming a plume in the Columbian Aquifer. Target Area 2 is one of the four areas in Area 6 where shallow groundwater (i.e., the top ten feet of the Columbian Aquifer) contains chlorinated solvent plumes. Target Area 2 originates in the vicinity of the Civil Engineering (CE) Shops and extends south about 1,500 feet. Target Area 2 is approximately 13.1 acres in size. An interim remedial action for OU11 was presented in one of the four RODs issued in September 1995.
OU12 is Target Area 3 of Area 6. Area 6 is defined by the associated of chlorinated solvents in groundwater forming a plume in the Columbian Aquifer. Target Area 3 is one of the four areas in Area 6 where shallow groundwater (i.e., the top ten feet of the Columbian Aquifer) contains chlorinated solvent plumes. Target Area 3 originates near Building 719 and extends south about 800 feet where it joins Target Area 1. The past release of trichloroethene (TCE) from the dip tanks is a suspected source of the contamination. Another suspected source is two former USTs that were removed in 1992 from the northeast side of Building 719. Target Area 3 is approximately 3.7 acres in size. An interim remedial action for OU12 was presented in one of the four RODs issued in September 1995.
OU14 is comprised of the Liquid Waste Disposal Area 21 (WP21) and the Industrial Waste Basins (IWBs). WP21is located within the West Management Unit (WMU), one of four management units into which the Base has been divided. DAFB owned and operated two surface impoundments that received hazardous waste from 1963 until 1984. The former impoundments, known as Site WP21, are located in the western portion of DAFB. WP21 covers approximately 192,000 square feet and is secured by a locked chain-link fence. The treatment system at WP21 was initially built in 163 to receive wastes from the engine overhaul shop (Building 719). In 1968, the system was expanded to accept waste from other facilities (Building 724-metal plating shop and Building 582-wash racks). The IWBs were the primary liquid receiving basins prior to treatment through oil/water separators. A ROD was completed in May 1998 that addressed the contaminated soil in WP21 and the beneath the IWBs.
The excavation, off-site treatment and disposal alternative shall consist of excavating and transporting the Volatile Organic Compounds (VOC) contaminated soils from the Liquid Waste Disposal Area 21 (WP21) site to an off-site, licensed treatment and disposal facility. The treatment option shall use thermal desorption to drive off the volatile contaminants from the soil. Off-gases and particulates shall be captured and/or destroyed. Treated residuals shall be disposed into a liscensed landfill. The tasks to be performed during this alternative shall include: 1) removal of the Industrial Waste Basins (IWBs), Oil/Water Separators (OWSs), a lift station, and associated piping; 2) removal of contaminted soils associated with these structures; 3) treatment of contaminated soil through thermal desorption; 4) disposal of treated soil at a licensed landfill as daily cover material; 5) removal of the WP21 soil cap; and 6) restoration of the site to a usable condition.
The contaminated soils from the IWBs and OWSs shall be excavated to the water table, estimated to be 12 feet below ground surface. The excavated soil shall be packaged for bulk shipment and transported by tractor trailer rig to the thermal desorption treatment facility. The treated residuals shall be disposed at a licensed landfill as daily cover material. The total volume of soil in the area to be excavated is estimated at 2600 cubic yards. This includes soil volume from the WP21 cap. An excess 1500 cubic yards of clean soil will be stockpiled/disposed on the Base. The time for all tasks to be completed under this alternative is estimated to be three months.
Captial Cost: $653,725
Annual O&M Cost: $0
Present Worth: $653,725
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