As many as 50 military bases and numerous civilian sites in Britain could have been contaminated with radioactive waste, says a government scientist. Ron Brown, from the Ministry of Defence's radiological protection service in Portsmouth (DRPS), warns that much of the contamination from old radium facilities is still to be uncovered.
Brown, a health physicist, has been overseeing the clean-up of one of the worst polluted military bases over the last five years. The MoD is spending two and a half million pounds digging up and disposing of large volumes of radioactive soil from RAF Carlisle, a former military equipment depot on the outskirts of the northern English city.
The contamination was discovered by accident in 1992, says Brown. Someone was walking across a patch of ground with a radiation monitor switched on and it suddenly started clicking quickly. Surveys later revealed that large areas of the 150-hectare site contained radium 226, which was used before 1960 to luminise paint for aircraft dials.
In the 1940s and 1950s RAF Carlisle incinerated thousands of luminous dials from old planes in accordance the "bash, bury or burn" disposal policy of the time. Unfortunately, says Brown, the radioactive ash from the incinerators was used to landscape the site.
As a result all seven sections of the base, four of which are linked by public roads, were contaminated. Brown says the ash was also used to pack in the bottom of fence posts around the site boundary. Hotspots of radioactivity up to 250,000 becquerels were found where unburnt dials had been left on the ground, he discloses. Such levels would be harmful inside the body, he says, and outside could burn the skin in hours.
Since 1992 scientists at DRPS have analysed up to 10,000 soil samples from RAF Carlisle and produced 30 reports. About 300 cubic metres of soil containing more than four becquerels a gram of radium 226 have been classified as radioactive waste and transported to the low-level waste dump run by British Nuclear Fuels at Drigg in Cumbria. Perhaps twice the volume of less radioactive soil has been tipped on nearby industrial waste sites.
The MoD expects the clean-up to be completed this year and intends to put the site up for sale. Local newspapers have reported an excess rate of cancer in the nearby village of Etterby, but ministry officials say there is no reason to connect that to RAF Carlisle.
Other sites in Britain known to have been contaminated with radium include a housing estate at Dalgety Bay in Fife and a military base at Ditton Park near Slough. Last month Britain's new environment minister, Michael Meacher, promised to clean up old radioactive waste dumps "as quickly as we can".