The most significant human-made source of radiation in the Irish marine environment is low-level liquid radioactive waste discharged from the Sellafield site on the north-west coast of England. For this reason, the EPA’s marine monitoring programme is focused on the east coast of Ireland.
The EPA marine monitoring programme involves the collection of seawater, seaweed, sediment, fish and shellfish from around the coast of Ireland. These samples are analysed for a variety of radionuclides in the EPA’s Radiation Monitoring laboratory in Dublin.
The following table shows the current sampling locations, samples types and radionuclides measured.
| Location | Frequency | Sample Types | Radionuclides Measured |
|---|---|---|---|
| Carlingford |
Quarterly Annually |
Mussels, oysters Winkles |
Cs-137 and other gamma emitting radionuclides. Tc-99, Pu-238, Pu-239, 240 and Am-241 (annual composite sample) |
| Ballagan/ Greenore | Bimonthly |
Sediment, seaweed Seawater |
Cs-137 and other gamma emitting radionuclides. Tc-99 (seaweed only) Cs-137 |
| Clogherhead | Quarterly |
Fish, prawns, lobster |
Cs-137 and other gamma emitting radionuclides. Tc-99, Pu-238, Pu-239, 240 and Am-241 (annual composite sample) |
| Kilmore Quay | Annually | Fish |
Cs-137 and other gamma emitting radionuclides |
| Killybegs | Annually | Fish |
Cs-137 and other gamma emitting radionuclides |
| Woodstown | Biennially |
Seawater Seaweed, sediment |
Cs-137 Cs-137 and other gamma emitting radionuclides |
| Galway | Biennially |
Seawater Seaweed, sediment |
Cs-137 Cs-137 and other gamma emitting radionuclides |
Offshore seawater samples are also collected annually by the Naval Service at six sites in the Irish Sea and analysed by the EPA for Cs-137.
The EPA’s marine monitoring programme shows that radionuclide concentrations from human-made sources are very low. The human-made radionuclide of greatest significance from the point of view of radiation dose is caesium-137 (Cs-137). Levels of Cs-137 in the Irish Sea have decreased steadily since the 1990s in line with decreased discharges from Sellafield as shown in the following chart (select ≡ and "view in full screen").
The radiation dose from human-made radioactivity to a member of the Irish public from consuming large amounts of seafood is significantly lower than that from natural radioactivity (such as polonium-210 and lead-210) and is much less than 1% of the total radiation dose received from all sources of radiation (both natural and human-made).
Results from our marine monitoring programme are available to download below.
