The Paducah Sun
Thursday, August 19, 2004
Toxic runoff ditch cleanup completed early, on budget
The $8 million cleanup of the gaseous diffusion plant's North-South Diversion Ditch was started last September.
By Joe Walker
Thursday, August 19, 2004
Contractors have cleaned up a ditch that for decades was a catchall for contaminated runoff and a place that some former workers say was a regular dump site for barrels of toxic, radioactive waste at the Paducah Gaseous Diffusion Plant.
The $8 million job was completed Tuesday, five months ahead of schedule and within budget, according to the Department of Energy. Since last September, more than 23,000 tons of soil were removed from a half-mile stretch of the North-South Diversion Ditch, which runs two miles from inside the plant fence to the north section of federal land at Little Bayou Creek.
Excavation had been delayed for more than two years because of disputes over what to do with the contaminated soil and the new accelerated-cleanup plan proposed by DOE. The problems were resolved a year ago when DOE and state and federal environmental regulators signed the agreement. The ditch work is the first project completed under the new plan, which has been challenged in court by some plant neighbors.
"This is a triumph of cooperation with our regulators," said Bill Murphie, DOE Paducah project manager.
The ditch was contaminated with wastewater pumped into the ditch for 40 years from a central building called C-400, where machinery and equipment were cleansed of hazardous chemicals and radioactive materials. In 1995, DOE began treating wastewater from the building and pumping it around the ditch to stop the spread of contaminants.
Although the sediment mainly contained uranium, heavy metals and polychlorinated biphenyls (PCBs), there were traces of most hazardous substances involved with the uranium enrichment process, including highly radioactive plutonium, neptunium and technetium, and trichloroethylene (TCE), a now-banned toxic degreaser.
During cleanup, the old soil bed of the ditch was removed in 85 segments, at a rate of about 300 tons per day. The ditch was sampled for contaminants before excavation began, and the soil was also monitored as it was removed. Samples were split with state regulators for independent analysis, verifying DOE results.
Murphie said tests showed such tiny amounts of radionuclides and TCE that the soil could be safely buried in a government landfill north of the plant. The excavated soil was replaced with a layer of clay and clean soil, and the area reseeded.
DOE is working with regulatory agencies on a sampling plan for the remaining 1-mile segment and other plant ditches to determine if other cleanup is needed, Murphie said.
In early 2000, northern portions of the ditch near Ogden Landing Road were sampled amid a Justice Department probe into a federal whistleblower lawsuit by three plant employees alleging the plant secretly contaminated workers and the public.
The Justice Department has since joined the case, involving allegations by some former workers that drums of contaminated material were dumped into the ditch for many years.
The ditch also was a focal point of major groundwater contamination discovered in 1998. After a few residential wells north of the plant were found to have traces of TCE and technetium, the government paid to provide municipal water to more than 100 homes.
Years of environmental investigation have pinpointed the cleaning building as a chief source of pollution of the 10-billion-gallon aquifer that extends to the Ohio River.
To help cut off that source, the Energy Department plans to heat the ground far below the surface and vacuum out vaporized contamination for carbon-filter or oxidation treatment.