A Scottish beach has been cordoned off as a "contaminated land" by environmental-protection authorities following discovery of "radioactive particles" there, thought to result from Ministry of Defence activities in the past. Former UK Prime Minister Gordon Brown has seen fit to write to the Defence secretary, urging the MoD to act. Surely this is a very serious business?
Well no, absolutely not: the so-called "contamination" which has been found at Dalgety Bay is insignificant as beach pollution goes. You would create a similar "hazard" by throwing a few thousand completely legal luminous watches into the sea there. You could keep the most radioactive "particle" yet found in your home forever in complete safety. You'd surely be ill-advised to build sandcastles in your swimming costume there and then fail to have a shower reasonably soon afterwards – say, within a few months – and it would be quite foolish to eat the sand or or seaweed or rocks – but that's true of every beach in the UK.
Going for a walk or a swim on the beach at Dalgety Bay is pretty much risk-free: and yet we learn that the Scottish Environmental Protection Agency (SEPA) has actually seen fit to cordon off parts of the beach, and considers that if nothing is done it may have to be placed permanently off limits.
Well, this is all because small bits of stuff containing radium have been found on the beach there since 1990. They have generally shown insignificant activity levels, but now SEPA says it has found three with higher activities: 3.6 MegaBecquerels, 4.5 MBq and one – described as an "extremely high in-field reading" – measured at 76 MBq.
So just how dangerous is this?
Well, for context it is perfectly legal to make and sell in the UK a luminous wristwatch containing up to 0.01 MBq of Radium-226, the substance in question. (In fact most of the danger comes from decay products – so-called "daughter isotopes" – which build up and remain present in a lump of radium as it slowly decays away, not the radium itself, but hazard assessments allow for this.) Thus the frightfully dangerous particles found at Dalgety are equivalent to finding a few hundred luminous watches lying about, or in one case, quite likely a freak reading, a few thousand of them.
Supposing you had picked up that 76-MBq particle and taken it home with you, perhaps keeping it on your mantelpiece as a souvenir. Supposing you have a very tiny home and you never go out, you might remain around 2m from it. That would cause you to sustain a calculated dose rate of 0.00329 millisievert per hour, assuming that your home has no walls as well. Your annual dose rate would be 28 millisievert. In fact, as you are not a mad hermit who lives in a tiny cave, it would be much less – well within safety limits, much, much less than nuclear powerplant workers or residents of various naturally radioactive areas around the world routinely sustain. This is an insignificant issue: and if you merely had a few of the ordinary several-MBq bits lying about, even more so.
The fact is, you could go and camp on the beach at Dalgety Bay for life and you'd be fine (well, as far as radiological hazards were concerned).
But wait: radiation danger gets a lot worse the closer you are to the source. What if you got one of these particles stuck to you? What if you ingested one somehow? Why, SEPA says:
If the sources were to be exposed through erosion and mobilisation over the winter period, they would pose a risk to the Dalgety Bay community ...
If someone comes into contact with one of the radioactive items found at Dalgety Bay they may be affected in several ways. Skin contact may cause radiation burns, breathing in radioactive material may cause damage to the lungs and respiratory tract and ingesting radioactive material may cause damage to the stomach and digestive system. In addition, exposure to radioactivity may cause an increased risk of the person developing cancer.
This is all quite true: the key is the repeated use of the word "may". Anything at all "may" happen. About the only thing which is actually plausible, however, is that you might get some Dalgety Bay sand or mud on your skin which might contain a bit of old radium big enough to have a noticeably high activity rate. SEPA have asked for a proper assessment of this danger, and here it is in pdf.
In short, the health consequences, again, are minimal:
A ‘Significant’ Ra-226 source ... can give a contribution to effective dose in about 1 hour of ~ 0.4 milliSievert ... These evaluations of contribution to effective dose need to be treated with care because of all the provisos regarding the role of alpha radiation in skin cancer induction [ie, alpha rays have not been shown to induce skin cancer as they can hardly penetrate the outer layers].
Provided you take a shower within a few weeks or otherwise get the particle off you, you'll be fine. You might suffer "radiation burns" – anything might happen – but probably not. Nobody knows as it has never happened. Even if you did get burned, the thing to remember about a radiation burn is it is just a burn. People get radiation burns on beaches all the time, from that enormous radioactive nuclear furnace in the sky, the Sun. The additional hazard on Dalgety Bay beach from radium will be tiny by comparison.
Yes, you could harm yourself by eating such particles: but again the hazards of eating sand or dirt are in themselves more likely to do you damage. As for breathing the stuff in, radium and its decay products are heavy stuff: a particle small and light enough to float on air currents will have a tiny activity level.
No: This whole thing is tosh, resulting plainly and simply from the modern hysteria over the dangers of radiation and the modern principle that such dangers – unlike other dangers – must by law be kept As Low As Reasonably Achievable (ALARA). "Reasonably Achievable" here means that the MoD is being expected to come and dig up huge areas of land and move all that dirt away to somewhere else, in order to remove a minuscule, imperceptible danger.
The presence of the water in Dalgety Bay, the tides coming in and out, the Sun in the sky overhead, cars driving down the road and the domestic appliances in the houses round about all pose a hugely greater danger to the local inhabitants than the "radioactive contamination" there. But nobody is saying that the bay must be drained, that a huge sunshield should be erected over the town, that cars or domestic appliances should be banned or incredibly heavily regulated – because they aren't "radiological".
You can tell that it's a modern hysteria, this, because the radium on the beach doesn't come from old nuclear weapons or reactors or something. It comes from instrument dials on old aircraft, destroyed by burning and landfilled there long ago. The aircrews who flew those planes happily sat for ages within inches of all these particles, collected together in a mass in the form of luminous paint, and never cared a jot.
Modern fearmongers at SEPA – and local MP Gordon Brown – might care to take note of their example, and realise just how pathetic it makes them look. ®