The end use recommendations for the Upper East Fork Poplar Creek Watershed were approved on May 7, 1998. The signed recommendations and an end use map are presented on page 43, page 44, and page 45

The Upper East Fork Poplar Creek watershed (see Figure 4.4), which includes the main Y-12 Plant area, is located between Pine Ridge and Chestnut Ridge. The headwaters of Upper East Fork Poplar Creek are near the S-3 Ponds. When the Y-12 Plant was built, the creek was rerouted through storm drains and its original tributaries were backfilled.

The original mission of the Y-12 Plant was to produce enriched uranium by an electromagnetic process. Y-12's current missions include stockpile stewardship for uranium and lithium materials; drawdown and disposition of special nuclear materials; and other complementary missions. Y-12 will continue to be used by DOE’s Defense Programs into the 21st century. Many of these activities are classified as national security issues by the federal government. Thus, the reuse of this part of theY-12 Plant for other purposes is not likely.

Currently, the DOE Defense Programs office "owns" about 5 million square feet of the total 7 million square feet of floor space at the 800 acre Y-12 Plant. Over the next 10 years, Defense Programs intends to surplus 1.3 million square feet, most of which is located in the high security area.

More than 70 sources of contamination lie within the Upper East Fork Poplar Creek watershed. The area contains an almost continuous nitrate- and uranium-238 contaminated groundwater plume, which originates from the S-3 Ponds and other sources within the plant. This plume, located deep in bedrock (300 to 400 feet), has migrated 400 feet down and 4000 feet laterally from its sources. It also contains other radionuclides and metals. Because of their mobility and the acidic environment, the nitrates and uranium extend into the central plant area, but other contaminants are fairly localized.

A carbon tetrachloride-contaminated groundwater plume exists in the east end of the Plant and extends off site under the Union Valley Industrial Park. The source of this plume is unknown; however, carbon tetrachloride was used in large amounts from 1943 to 1946 in processing source material for the electromagnetic separation process.

Three monitoring stations (8, 17, and the North/South Pipe) are used to measure mercury releases to Upper East Fork Poplar Creek. Over time, mercury levels have steadily decreased in the creek. The highest concentrations of contaminants are seen during rainy months. Mercury from historic releases is also a contaminant in soils.

Over time, two ponds have been used to handle contaminated surface water exiting the Y-12 Plant to the east prior to entering Lower East Fork Poplar Creek. These ponds concentrated mercury and other contaminants in sediments. The first of these, New Hope Pond, was closed under RCRA but may still be contributing to groundwater contamination. The replacement, Lake Reality, is still in operation.

Chestnut Ridge lies south of the Y-12 Plant and extends to the northern edge of Bethel Valley Road. This area consists of more than 2,000 acres and has as many as five different watersheds, all draining south into the Clinch River.

Chestnut Ridge contains a variety of disposal sites that are regulated by CERCLA or RCRA (or both), depending on the type of contamination.

CERCLA sites include the United Nuclear Corporation site, the Filled Coal Ash Pond, Rogers Quarry, the Chestnut Ridge Borrow Area Waste Pile, the Mercury-Contaminated Gully Soil Pile, the Criticality Testing Facility, and the Uranium Oxide Vaults. These sites contain a wide variety of contaminants including nitrate contaminated sludges fixed in cement, arsenic, copper, lead, zinc, mercury, uranium, and fly ash. All of these sites are being addressed under CERCLA; several are closed and many have Records of Decision.

RCRA/CERCLA integrated units on Chestnut Ridge include the Chestnut Ridge Security Pits, the Kerr Hollow Quarry site, and the Chestnut Ridge Sediment Disposal Basin. Contaminants in these sites include cadmium, chromium, lead, nickel, mercury, uranium, carbon tetrachloride, and chloroform.

RCRA Regulated Units in Chestnut Ridge include the East Chestnut Ridge Waste Pile, and the Contaminated Soils Storage Area and Storm Sewer Sediment Drying Facility which contain mercury, uranium, and PCBs.

Several industrial landfills are also located on Chestnut Ridge. The Class 2 (industrial) permitted facilities include Landfills II, IV, and V. Landfill II was closed in 1996. Landfill IV is still active and has a 72-year remaining life. Class 4 (construction/demolition) permitted facilities include Landfills VI and VII. Landfill VII has a 5-year remaining life. Landfill VII has not received any waste.

Members believed that the reuse of the Y-12 Plant following remediation could provide a significant benefit to the local economy. Concerns were raised about what types of future industrial use should occur at the facility. The EUWG wanted to avoid harm to workers and resources from both future DOE activities and new industries. Members believed new industries moving into the Y-12 Plant should not pose an unacceptable risk to human health or the environment. Special concerns were expressed regarding the nearby Scarboro and Woodland communities.

Two alternatives were evaluated for the Y-12 Plant: controlled industrial and uncontrolled commercial/industrial. Uncontrolled industrial would require removal of about 4 million cubic yards of soil, with costs ranging from $700 million to $3 billion. The Group noted that the eastern area of the Y-12 Plant has only a few areas requiring remediation. The central plant area would require more extensive remediation to allow for an uncontrolled industrial end use, while end uses in the west would be limited by national security considerations.

Members recognized that New Hope Pond is a RCRA-closed area, but does not meet the criteria for uncontrolled industrial and that residual contamination may continue to contribute to groundwater contamination. The Group decided to include New Hope Pond in the recommendation, but recognize that it will require continued federal government control and may have limited use.

In dealing with groundwater issues, members agreed that the federal government should maintain responsibility for groundwater. Many members believed the recommendation should state that groundwater contamination sources be contained, since contaminants are currently moving off site under privately owned land. Overall, members believed treatment options could not make groundwater in the Y-12 Plant area suitable for use in the foreseeable future. Although members realized the challenge this presents, it was felt that DOE should do whatever it can to minimize the spread of the off-site Union Valley groundwater plume. This groundwater plume restricts the use of nearby uncontaminated water because of concerns that such use will alter the contaminated groundwater flow. Members agreed that DOE should control groundwater to allow for unrestricted use of off-site uncontaminated groundwater.

Many members were also concerned with the quality of surface water since Upper East Fork Poplar Creek feeds Lower East Fork Poplar Creek. At present, the water quality is maintained in part by augmenting flow with water pumped from the Clinch River. EUWG members believe water quality in Upper East Fork Poplar Creek must be maintained so that Lower East Fork Poplar Creek is safe for commercial and residential uses.

The EUWG felt that the DOE Defense Programs national security facilities should eventually be consolidated within the security fence in the west end of the Y-12 Plant, and only those DOE missions that could co-exist with non-DOE activities and private industry remain in the eastern area. Current plans show that the majority of floor square footage now planned for surplus lies within the security area and not in relatively uncontaminated areas. Many ORNL missions and operations that support Defense Programs will remain outside the security fence in the eastern plant area. When Defense Programs finally vacates the western area, it also should be released for controlled industrial end use, which allows for use by private industry.

Recognizing that DOE’s Defense Programs will continue to use the site for the foreseeable future, members believe it is important that ongoing efforts to clean up soils, sources, and releases continue no matter which DOE program is responsible for the facility. Releases within the high security area also need to be addressed.

Members believed Chestnut Ridge was within the Group’s scope, since it is a contaminated area. Because nothing can be placed on closed hazardous waste landfills, most of the land in Chestnut Ridge cannot be used for other purposes.

As a result of the discussions on Upper East Fork Poplar Creek, two new Community Guidelines were developed: (1) DOE should not abandon buildings in place, and (2) the need for future tenants to ensure the protection of workers’ health, the public and the environment.

• One member felt that because the Remedial Investigation did not fully characterize contaminated groundwater plumes, DOE’s ability to make a remedial decision would be limited.
• Some concerns were expressed that DOE will not be able to deal with contamination at Y- 12 without removing buildings. Mercury is present inside and under some building foundations.