Middlesex Sampling Plant

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The Middlesex Sampling Plant is located in the Borough of Middlesex, New Jersey, in Middlesex County, approximately 56 kilometers (35 miles) northeast of Trenton and 42 kilometers (26 miles) southwest of Newark. The 3.9 hectare (9.6 acre) site is bordered on the east by residential properties on Mountain Avenue, on the south by William Street, and on the north by the Lehigh Valley Railroad line.

LOCALITY MAP

FACILITY MISSION

The Manhattan Engineer District established the sampling plant in 1943 to sample, store, and ship uranium, thorium, and beryllium ores. Manhattan Engineer District operations at the site ceased in 1955, but the Atomic Energy Commission later used the site for storage and limited sampling of thorium residues. All Atomic Energy Commission activities at the site ended in 1967. Onsite structures were decontaminated to levels acceptable at the time.

SITE MAP

From 1969 to 1979, the site was a training center for the U.S. Marine Corps. In 1980, it was returned to the Department of Energy, as the Atomic Energy Commission's successor agency, and designated for cleanup under FUSRAP.

Today, the Department of Energy monitors and maintains the site, which includes two soil storage piles containing approximately 51,000 cubic meters (66,300 cubic yards) of material; an office building; an old boiler house; and the former process building, which is used as an archive facility for radiological media samples. Addition of approximately 17,000 cubic meters (22,000 cubic yards) of building materials and in situ soil and asphalt brings the total site waste volume to an estimated 68,000 cubic meters (89,000 cubic yards).

The Department of Energy stores material from past area cleanups at the site in two piles. The larger pile, which was constructed in 1981, contains approximately 27,000 cubic meters (35,100 cubic yards) of radioactively contaminated soil and debris (low-level waste) generated during residential cleanups. The second pile, built between 1984 and 1986, contains approximately 24,000 cubic meters (31,200 cubic yards) of waste from cleanup of the Middlesex Municipal Landfill. In addition to radioactive constituents, the landfill pile also contains metals such as lead and cadmium.

FUTURE USE

Future use of the property will depend on the final remedy chosen for the site. The Department of Energy is considering treatment, capping in place, or excavation and transportation of materials to an offsite disposal facility. This estimate assumes that the final remedy will involve excavation and onsite capping of soils, with controlled access including long-term monitoring and maintenance.

ENVIRONMENTAL RESTORATION

Environmental restoration activities at the site are designed to identify and evaluate contaminated areas through surveying and sampling, to devise cleanup strategies, and to conduct cleanups as needed. Activities will focus on site grounds; four onsite buildings; two soil storage piles created during past cleanup of area properties, including the Middlesex Municipal Landfill; and a drainage ditch that exits on the southern end of the site.

All activities are coordinated with key regulators, including Environmental Protection Agency Region II, the New Jersey Department of Environmental Protection, and the local health department. Environmental documentation for the remaining actions to be taken at the Middlesex Sampling Plant will include an engineering evaluation/cost analysis and will incorporate National Environmental Policy Act values.

Material within the storage piles is contained by synthetic coverings that are sealed, secured around the edges, and fastened with helical anchors. The cover on the oldest pile, which was created during cleanup of nearby residential and commercial properties in 1981, was replaced in 1992. Asphalt, concrete, or grass covers contaminated soils on the site grounds. A settling basin at the site outfall allows sediments to precipitate out of water before it exits the site. A concrete berm surrounding the piles directs runoff water into drains that feed the settling basin.

Major Environmental Restoration Activity Milestones

TASK	COMPLETION DATE Fiscal Year
Assessment (Engineering Evaluation/Cost Analysis with Action Memorandum)	1998
Remedial Action	2003
Transfer Site to Grand Junction Projects Office Long-Term Surveillance and Monitoring Program	2004

ASSESSMENT

Several radiological investigations have been conducted at the Middlesex Sampling Plant. In 1967, after initial decontamination and before the Atomic Energy Commission released it, the site was surveyed and determined to be suitable for release according to the standards then in effect. When the site was resurveyed in 1976, the results identified contamination above relevant guidelines both onsite and offsite. The Department of Energy conducted cleanup of offsite residential properties in 1980 and 1981 and cleaned up the Middlesex Municipal Landfill between 1984 and 1986. A third radiological survey was conducted in 1983 to prepare for an engineering evaluation for future cleanup of the site in its entirety.

In 1991, the New Jersey Department of Environmental Protection requested a study to determine the nature and levels of radioactive and chemical contamination in the storage piles and in situ soils. This state agency selected and approved a systematic sampling approach for the investigation; samples were collected in a manner that ensured representativeness of the contained waste. Composite samples were analyzed to determine average activity levels of uranium­238, radium­226, and thorium­232 in the storage pile material. Both the vicinity property pile and the landfill pile were analyzed for Resource Conservation and Recovery Act characteristics and toxicity characteristics leaching procedure constituents. The tests indicated that the piles do not contain Resource Conservation and Recovery Act hazardous waste; however, samples from the landfill pile exceeded the regulatory limit for lead, and two samples exceeded the regulatory limit for cadmium.

In 1990 and 1991, the Department of Energy conducted an intensive phased sediment investigation in and along the drainage ditch exiting the southern end of the site. It supplemented this investigation with limited sampling in 1992. During soil sampling along the bank, the guideline of five picocuries per gram above background was exceeded in only one sample [collected 0.9 meter (three feet) from the outfall]; however, sediment samples showed elevated activity downstream for a distance of nearly 60 meters (200 feet) from the outfall.

The Department must address approximately 68,000 cubic meters (89,000 cubic yards) of material for the site to comply with guidelines. This estimate includes approximately 13,000 cubic meters (17,000 cubic yards) of asphalt/gravel and soil from the grounds, 3,650 cubic meters (4,775 cubic yards) from dismantlement of the boiler house and process building, and 51,300 cubic meters (67,000 cubic yards) of material stored onsite. In addition, the Department of Energy must decontaminate parts of the garage and the office building.

Since 1980, the Department has conducted quarterly environmental monitoring activities to measure radioactive constituents in ground water and surface water, radon in the air (building interiors and outdoors), and external gamma radiation. In 1990, metals were added to the quarterly analyses of ground water and surface water. In 1991, the Department initiated analyses for volatile and semivolatile organic compounds, and conducted a radiological investigation of the storage piles and site soils in conjunction with testing for chemical constituents. The drainage ditch exiting the southern border of the site was sampled for radioactive contaminants in 1990, 1991, and 1992.

In 1992, the Department modified the ground-water monitoring program. It reduced the number of wells sampled, and changed the sampling frequency from quarterly to annually. In mid­1994, all but one of the existing wells were plugged and abandoned, and seven new monitoring wells were installed. The Department replaced the wells because (1) the older wells were unreliable, (2) well installation technology has improved, (3) standards have become more stringent, and (4) specific depths need to be reached for monitoring.

Through the environmental monitoring program, the Department monitors and periodically samples air, ground water, and soil to detect any above-background contamination associated with the site. An annual report compiles and interprets the monitoring and sampling data from the previous year. During activities such as pile removal, building dismantlement, or ditch excavation, the Department conducts additional monitoring to ensure that no contaminants are spread as a result of the work.

REMEDIAL ACTION

Required actions that have been completed include removing contamination from residential and commercial properties in 1980 and 1981, removing contamination from the Middlesex Municipal Landfill in 1984 and 1986, storing these materials at the site, conducting environmental monitoring, and performing surveillance and maintenance. After removal actions were conducted, the Department restored the vicinity properties to their original condition.

The drainage ditch that exits the site contains isolated spots of elevated radioactivity along the ditch line. The Department of Energy currently plans to clean up these spots under a Comprehensive Environmental Response, Compensation, and Liability Act removal action, using heavy equipment and general construction/excavation protocols. The removal will probably require construction of a haul road along the ditch line as a transportation route back to the existing storage piles onsite.

The Department will plan the cleanup of the site storage piles and grounds through an Engineering Evaluation/Cost Analysis. It is evaluating many options for the final site remedy, including capping in place with cover, removal and offsite disposal, and partial removal with some onsite disposal.

The scenario used for the Baseline Environmental Management Report cost estimate assumes excavation and onsite capping of the contaminated soils. The cost estimate also includes decontamination of two buildings (garage and administration building) and demolition of two additional buildings (process building and boiler house). The total waste volume assumed for the cost estimate is 68,000 cubic meters (89,000 cubic yards). The Department will transfer long-term surveillance and maintenance to the Grand Junction Projects Office in FY 2004.

FUNDING ESTIMATE

The following table presents estimated funding information for the Middlesex site.