Madam, - According to your Editorial of July 12th, the "fundamental matter of whether nuclear energy is justified must be distinguished from the Sellafield plant's efficiency and whether it illegally pollutes the Irish Sea".
The argument about the pollution of the Irish Sea is one that is used frequently by those opposed to nuclear power. By asserting that the Irish Sea is the most radioactively polluted ocean in the world they presumably wish to imply that our health is gravely at risk. They contend that this pollution originates from the Sellafield plant, is serious and constitutes one of the main reasons for taking legal action to close the plant.
Let us examine the actual extent of this so-called radioactive pollution. Like all the oceans, the Irish Sea contains naturally occurring radioactive material, mostly uranium and radioactive isotopes derived from it, such as radium, radon and polonium. The amounts of additional radioactivity discharged from sources such as Sellafield, other industries and hospitals are trivial in comparison with the natural and unavoidable radioactive substances already in the sea.
Nevertheless, because of public concern, the Radiological Protection Institute of Ireland (RPII) monitors the Irish Sea for radioactivity. Seafood provides the only significant pathway to humans from the discharged radioactivity.
The RPII estimates that a heavy consumer of sea food (about a half-pound per day) receives an annual dose of less than 2 microsieverts from Sellafield discharges. This is about 1 per cent of the 148 microsieverts received from naturally occurring radioactivity in the same seafood. In order to help the reader appreciate the size of this dose, a flight from Dublin to London incurs a dose of about 3 microsieverts. Also, the average annual dose to a member of the Irish public from all sources is about 3,620 microsieverts.
Even in the unlikely event of everybody in the country eating a half-pound of seafood from the Irish Sea every day of the year, the dose would not cause a discernable health hazard. Moreover, future doses are likely to be lower because of the gradual and continuing reduction in the discharges to the Irish Sea from Sellafield, in accordance with a number of international conventions and agreements, notably the Convention for the Protection of the Marine Environment of the North East Atlantic (OSPAR).
It is therefore evident that discharges of radioactive material into the Irish Sea cause no more than trivial radiation exposure; bearing in mind the legal maxim De minimis non curat lex ("the law doesn't concern itself with trifles"), we believe that convincing judges that the Sellafield discharges are illegal will be impossible. - Yours, etc,
DAVID SOWBY,
Knocksinna Crescent,
Dublin 18;
FRANK TURVEY,
Church Road,
Greystones,
Co Wicklow.