MONTREAL

The Canadian government has ordered a halt to the disposal of liquid waste from Atomic Energy of Canada's main nuclear research site, following protests from environmental groups provoked by details of leaks of radioactive waste water.

According to Canada's Atomic Energy Control Board (AECB), tritium levels in the leaks at Chalk River, Ontario, are well within regulatory standards and are not a danger to public health — despite the fact that some of the waste has entered the Ottawa River, whose waters are used for drinking.

The situation echoes that at Brookhaven National Laboratory, New York, whose director resigned and whose long-time contractor was sacked following tritium leaks (see Nature 387, 114; 114> 1997). In both cases, government action seems to have been prompted by public concern rather than by evidence of a clear danger.

The leakage, which has taken place over a 20-year period, was from uranium fuel storage bays for the now inoperative NRX research reactor, and put thousands of litres daily into the river. Atomic Energy of Canada Ltd (AECL) made studies over the years and reported them in annual reports to the AECB but did not otherwise go public with them.

The warden (the senior elected official) of Renfrew County, where the Chalk River plant is situated, has complained that his council was never told of the leak. Others who feel the council should have been informed include Lynn Jones of nearby Pembroke, who uncovered the extent of the leak via a request filed under Canada's ‘access to information’ law.

AECL points out that it reported the leak in publicly available annual reports, as it was required to do, but did not want to alarm the public unnecessarily by further disclosures.

Two more leaks were revealed later, in pipes carrying water from routine drainage of reactor liquids into a gravel-filled pit on AECL property. The AECB says that the total amount of tritium in the leaks corresponds to only 0.01 per cent of the legally permissible limits on releases from the site.

Public concern about the leaks is linked to an offer by the nearby town of Deep River, which has since been dropped, to accept radioactively contaminated soil for storage at Chalk River. The soil is from a uranium processing plant near Port Hope, Ontario. Opponents of the plan questioned whether Chalk River is capable of storing the soil if it cannot adequately control its own waste.

Robert Potvin, an AECB spokesman, admits that AECL “should have been a little more open to local communities”.