High levels of radioactive tritium found in Pembroke landfill
MARTIN MITTELSTAEDT – ENVIRONMENT REPORTER – December 26, 2007
The Ministry of Environment has found elevated levels of radioactive tritium in ground water at the municipal dump serving Pembroke, Ont., and several other nearby Ottawa River valley communities.
The dump, the Alice and Fraser Township Landfill, is not licensed to receive radioactive waste, and it is not known exactly how tritium, used to make glow-in-the-dark lights, among other products, and nuclear weapons, got into the dump.
But the discovery, made earlier in December, is being played down by the ministry because the amount of radioactivity was well below Ontario’s drinking-water limit.
Ministry spokesperson Kate Jordan said the Pembroke finding wasn’t high enough to warrant further action. “While there was tritium in the ground water at the site, [it was] well below our ministry standards,” she said. “We don’t feel that they pose a risk to the community or to the environment.”
The highest level – 1,000 Becquerel/Litre – is one seventh Ontario’s drinking water standard. One Becquerel is a radioactive disintegration per second.
But Ontario’s limit is lax by international standards and is currently under review by the government. The reading would have exceeded by wide margins California’s goal of having no more than 15 Bq/L, and Europe’s of having no more than 100 Bq/L, in water supplies.
California’s strict limit is based on the amount of tritium consumed over a lifetime that would cause no significant health risk, which it defined as one extra cancer in a million exposed people. Based on the California risk calculation, Ontario’s limit deems acceptable about 466 extra cancer cases.
The ministry testing is believed to be the first in Canada to find elevated amounts of tritium, a radioactive form of hydrogen, at a municipal landfill, and was prompted by a request from an environmental group in the community, located about 150 kilometres northwest of Ottawa.
“If these levels were found in any other jurisdiction there would be an immediate investigation. Ontario Ministry of Environment staff are using permissive and outdated provincial tritium standards as an excuse to avoid action,” contended Ole Hendrickson, a spokesman for Concerned Citizens of Renfrew County, the local group, in a statement.
Elevated amounts of tritium have also been found at dumps in both the United States and the United Kingdom in water that collects under landfills, known technically as leachate. Studies in those countries suggest the radioactivity is coming from the disposal of glow-in-the-dark signs, such as emergency-exit lights used in buildings, and products such as luminous watch paints. A group of U.S. researchers warned earlier this year that landfill workers exposed to construction debris may be at high risk of tritium exposure due to releases from the signs.
The only other testing in Ontario, at a landfill near Waterloo by the ministry in 2004, found low amounts of tritium around 10 Bq/L to 20 Bq/L. Some tritium is produced by natural processes and rain contains about 2 Bq/L.
Although the ministry doesn’t know precisely how the dump water got its radioactivity, Ms. Jordan said the source may have been glow-in-the-dark products.
In response to written questions, the Canadian Nuclear Safety Commission, the federal atomic watchdog, said it believes glow-in-the-dark signs caused the contamination. Canadian nuclear regulations allow the radioactive signs to be tossed into landfills, provided certain limits on their radioactive content are met.
Mr. Hendrickson said he is not aware of efforts by the CNSC to see if discarded signs meet the regulatory conditions and the watchdog wasn’t immediately able to confirm or deny his statement. More at Globe and Mail…
The Waster: The presence of tritium in UK landfills has been known about for more than 10 years and is well documented.