Discarded green-glowing signs, containing radioactive tritium, contaminate landfill water here and across state. Experts say levels don’t pose health threat.
By Ad Crable
Updated Feb 19, 2007 15:58
After all, new regulations required all landfills to monitor incoming trucks for any radioactive material.
The origin, they found to their surprise, was exit signs.
At three of the four landfills here, and at more than half the 54 solid waste landfills in the state, the levels of tritium in water flowing from the landfills exceeded what is allowed in drinking water.
Above-normal levels of tritium were found at the county’s Frey Farm Landfill in Manor Township; the Lanchester Landfill on the Lancaster-Chester border; the Conestoga Landfill on the Lancaster-Berks border; and the Milton Grove Demolition and Tire Recycling Center near Mount Joy.
All but the Frey Farm Landfill had tritium in leachate — the water that flows down through waste — at levels exceeding drinking water standards.
That water is discharged into such waterways as the Conestoga River, Susquehanna River and Little Chickies Creek.
State Department of Environmental Protection officials emphasize that the levels of tritium found do not pose a health threat to residents here or anywhere else in Pennsylvania because the tritium is vastly diluted before reaching any drinking-water intakes.
“It truly would be a fraction” of original levels, says DEP spokesman Ron Ruman.
Three-page letters to head off public alarm were recently sent by the DEP to local officials whose municipalities host the landfills.
But the DEP wants to keep tritium out of landfills. So they searched for the source of the radioactive gas, at high levels a cancer-causing agent normally associated with the production of nuclear energy.
Tritium gas is typically used in the green exit signs placed in many buildings so that the signs continue to glow in case of a power failure. Red-lettered exit signs do not contain tritium.
State and federal laws require that unused exit signs be sent back to the manufacturer, where the tritium is removed and recycled, or taken to one of the two low-level radioactive waste landfills in the United States.
But the reality is that many, perhaps most, of these exit signs get thrown out with the trash or taken to landfills when old buildings are demolished, the DEP says.
When the signs reach landfills and are broken, the gas quickly finds its way into water that flows through landfills.
Radiation monitoring at the landfills does not detect the incoming signs because they give off beta radiation, which the detectors don’t pick up, Ruman said.
Federal drinking-water standards allow up to 20,000 picocuries per liter of tritium. At the Conestoga Landfill, collected leachate had nine times the maximum level allowed — the highest of any landfill in the state.
At Milton Grove, in Mount Joy Township, one sample found 29,300 picocuries. At Lanchester, the highest level was 30,900.
At Frey Farm, the highest level found was 6,540. Leachate there is pumped to the nearby Lancaster Area Sewer Authority treatment plant and discharged into Dry Run, a tributary of the Susquehanna.
Manor Township supervisors recently received a letter from the DEP about the tritium finding at Frey Farm.
Supervisor John May said he was relieved that drinking water sources do not seem to be affected.
“There’s no way to remediate this, apparently,” he said. “I guess the idea is to stop the practice of throwing them away indiscriminately.”
The DEP has appealed to the U.S. Nuclear Regulatory Commission to do a better job of labeling and informing the public about the proper disposal of exit signs containing tritium.
In addition, the DEP is now requiring the 54 landfills to begin testing for tritium in leachate.
Tritium has had a high profile in the news lately. Unreported tritium leaks at three nuclear plants in Illinois prompted the state attorney general to sue Exelon Corp. over groundwater contamination.
Exelon launched a fleet-wide search for tritium leaks, including at its Three Mile Island and Peach Bottom nuclear plants.
A leak of tritium into groundwater at TMI occurred last summer, but levels never exceeded drinking-water standards and didn’t reach the Susquehanna, Exelon officials said.
