MONTGOMERY, PA (AP) Glow-in-the-dark exit signs that once lit the way to safety in hospitals and other buildings appear to be seeping elevated levels of radioactive tritium into several landfills across the state after having been tossed into the trash.
The signs, typically thrown out after a construction project, can break, releasing the once-contained tritium into the watery mix of landfill residue eventually released into rivers and streams.
The good news? You can still drink the water. A state study concluded that the murky fluid known as leachate is so sufficiently treated and diluted after oozing out of a landfill that tritium levels fall far below dangerous levels before entering a drinking water supply.
Still, state environmental officials have ordered landfills to start regularly testing for tritium as a precaution. Approximately 60,000 signs containing tritium are in use in Pennsylvania, according to federal estimates.
“Although DEP has concluded there is no immediate or long-term threat to the public, we do believe that long-term monitoring and reporting is appropriate,’ Thomas Fidler, deputy secretary of the Department of Environmental Protection (DEP) said in a letter to municipalities close to the 54 active landfills tested.
“There are no other known sources of tritium in industrial or consumer products that would cause these levels of tritium in leachate,” Fidler wrote.
Tritium is a radioactive form of hydrogen, and exposure to it is not uncommon; for instance it can be released naturally through cosmic radiation, though at very low doses, said Barry Ganong, a chemistry professor of Mansfield University.
“In water, it’s not a lot of harm even if you ingested a little bit,” Ganong said. “You need a fairly large dose to be too concerned about it.”
Tritium is more concentrated in water used in nuclear reactors. Studies have shown long-term exposure to tritium can lead to cancer and birth defects.
At the Lycoming County-owned landfill in Montgomery, the DEP measured tritium levels in the leachate last fall at 48,200 picocuries per liter, more than twice the 20,000 picocuries per liter limit set by the federal Environmental Protection Agency for drinking water to be deemed safe.
But people usually don’t drink water straight out of landfills. At Montgomery, leachate gets funneled from the stinky decomposing trash mounds to a dark, bubbly pool where it gets treated before being piped to another facility for a second treatment.
The treated water is then released into the Susquehanna River. At that point, the tritium gets diluted to less than 1 percent of 20,000 picocuries per liter, well below the EPA’s safe drinking limit, the DEP said.
“It’s so small, it’s not affecting anything,” said R. Stephen Tucker, director of the Lycoming County-operated landfill in Montgomery.
Most of the tested landfills had tritium, and more than 20 samples showed contamination beyond safe drinking water standards, the DEP found.
The Conestoga Landfill in New Morgan, Berks County, had the highest tritium contamination, more than nine times above the unsafe line. But the DEP said the tritium was diluted to less than 1 percent of 20,000 picocuries per liter just before water entered the New Morgan drinking supply.
“So minor, it’s not considered a problem,” Carolyn Williams, borough manager, said.
The signs in question contain tritium sealed and contained inside glass tubes arranged in the word “exit.” The signs, which may have warning labels, don’t require electricity to be lit, proving valuable in case of a power outage.
The Nuclear Regulatory Commission oversees licensing. Regulations say the signs must be disposed either by returning them to the manufacturer or dropping them off at one of two low-level nuclear waste facilities in Barnwell, SC, or Hanford, WA.
But part of the problem is that many people may not be aware Spokesman Ron Ruman said.
The state’s tritium testing began in 2004. That same year, landfills also began state-mandated testing for other radioactivity, with trucks passing through a radiation monitor before entering the landfill.
The Lycoming landfill takes deliveries from approximately 230 trucks a day, though the radiation detector typically finds suspicious readings only approximately eight times a year, Tucker said. Radiation from an exit sign hidden in a load of trash likely wouldn’t be found because of the low dosage.
The state’s separate leachate tests can detect tritium. Layers of tough plastic, clay and other linings around a landfill typically prevent leachate from seeping into groundwater and funnel it into treatment facilities.
Ruman said the NRC ultimately holds responsibility over what happens to the tritium exit signs, and the federal agency should conduct more outreach.
The NRC said current regulations are more than sufficient and that it has recently installed requirements that would improve awareness of how signs should be disposed properly.
“The incidents of mishandling, loss or breakage that have occurred constitute a low potential risk to public health and safety,” Jack Strosnider, director of the NRC’s nuclear material safety office, said in a letter to Fidler.
The state doesn’t plan to test closed landfills. “We don’t see any particular issues there,” Ruman said. “We want to try to keep this out in the future.”