The overall levels of radioactivity in the Irish marine environment continue to fall, but the individual contribution of one radioactive substance is rising according to the latest study released by the Radiological Protection Institute of Ireland.
The study measures radiation from all sources, but indicates that radioactive discharges from the Sellafield nuclear reprocessing plant in Cumbria continue to be the overwhelming source of contamination of the Irish Sea.
The report details the results of fish, shellfish, water, sediment and seaweed sampling around the Irish coastline for 1996-97.
The data show that "the radiation doses to Irish people continue to fall slightly each year and do not pose a significant health risk", according to RPII deputy chief executive, Mr John D. Cunningham.
While it was "safe to continue eating fish and shellfish from the Irish Sea and enjoying the amenities of our seas", Mr Cunningham repeated the institute's contention that any contamination of the marine environment due to an installation from which Ireland derived no benefit remained "highly objectionable from an Irish viewpoint".
He also highlighted the rising levels of the radioactive element, technetium-99. Levels of this substance were increasing, but it made only a small contribution to the overall exposures to those eating fish or shellfish from the Irish Sea.
"Nevertheless, the increased concentrations are not acceptable and the discharges should be substantially reduced and eliminated," Mr Cunningham said. "The target of discharges close to zero should be achieved as soon as possible."
A heavy consumer of seafood from the Irish Sea from the most contaminated waters off our coasts could be exposed to 1.4 microsieverts of radiation based on the 1997 figures. This represents less than 1 per cent of the annual average dose of 3,000 microsieverts received from all sources of radiation. The 1996 figure was 1.6 microsieverts.
In the early 1980s this dose would have stood at about 70 microsieverts. The contribution from technetium-99 in 1997 stood at about 15 per cent of the total exposure with the radionuclide caesium-137 making up the bulk of the remaining 65 per cent.
