A leading nuclear expert has said Caithness beach must be closely monitored after a radioactive fragment was found washed up onshore.
Dr John Large, who has advised on governments around the world, said the tiny particle found on Sandside beach was probably discharged into the sea decades ago and could threaten local communities.
The particle from Dounreay, which was the 275th discovered since the discovery of the first in 1984, contains radioactive americium and can have severe effects on the human body if ingested.
Dr Large said: “The trouble is that 20 or 30 or so years later it has turned up on a beach. If it reaches the surface – which is quite possible given natural disturbance by the tide etc – and gets dried out it can become airborne, thus threatening local communities. It is alarming.
“Of course it is serious. There’s not a lot you can do either – because finding these particles is a random process, you cannot predict where they are.
“Monitoring needs to be stepped up because there is a real risk these particles could end up in areas of population.”
A spokeswoman for Dounreay said: “Addressing the legacy of radioactive particles in the marine environment around Dounreay is an important part of the site’s decommissioning programme. The particle monitoring regime for external beaches has been carried out for many years and is reported on our website.”
Sand sized fragments were released into the sea from Dounreay in the 1960s and 1970s, with work to recover the particles completed between 1990s and 2012.