ITHACA, N.Y. -- Although Cornell University's former low-level radiation disposal site (RDS) in Lansing does not pose unacceptable health risks, the New York State Department of Environmental Conservation (DEC) has announced a final, $10 million strategy for cleaning up the site.

The state plan, known as a record of decision, calls for constructing an underground clay wall around the waste area, injecting cement grout into fractured rock to isolate the most highly contaminated groundwater and using recovery wells to remove paradioxane, the main contaminant at the site, from the groundwater.

"The clean-up plan addresses the disposal area itself and groundwater contamination extending about 400 feet southwest of the site to Snyder Road," says Donna Connery, project manager for Cornell's Environmental Compliance Office. "Groundwater contaminated by paradioxane that already has left the site will be removed from a series of recovery wells, constructed in 2001 for this purpose along Snyder Road. The groundwater will then be treated at the existing treatment plant now being used for Cornell's former chemical disposal site (CDS).

"These strategies should effectively isolate the waste from the environment and minimize further movement of contaminants in the groundwater," Connery says.

The DEC's record of decision, which spells out the rationale for the final plan and includes the alternatives considered and responses to public comments, is available for public review in Ithaca at Tompkins County Public Library and Cornell's Environmental Compliance Office, Pine Tree Road, and in Lansing at Lansing Village Hall.

Between 1956 and 1978, research materials containing low-level radioactivity were buried, in accordance with state and federal regulations in force at that time, in Cornell's two-acre RDS, north of Ithaca Tompkins Regional Airport. Studies of the site and monitoring have been under way since 1984. In 1996, an impermeable cap was installed over the site to reduce penetration by surface water. Last year, the DEC discussed the clean-up plan for the RDS at public meetings, in newsletters and news articles. The agency also held a formal 60-day public comment period.

Paradioxane, a solvent that was used in radiation experiments, is of particular concern because it has migrated from the site, Connery says. A new ultraviolet oxidation system at the treatment plant will be used to treat the water and remove the paradioxane.

Construction of the groundwater recovery system was completed in 2001, with construction of the barrier walls around the disposal area to follow after regulatory approval of the design. Operation of the RDS groundwater recovery and treatment system is expected to start this year and continue for about 20 years, with ongoing monitoring.

Related World Wide Web sites: The following site provides additional information on this news release.

o RDS : http://eco.pdc.cornell.edu/DSCdefault.html .

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