1. Radiation in Everyday Life – an Irish Perspective
L. Currivan1, C. O’Connor1, N. Cunningham1, K. Kelleher1, S. Long1, M. Lewis2, P. McGinnity1, V. Smith1, C. McMahon1
1Radiological Protection Institute of Ireland, 3 Clonskeagh Square, Dublin 14, Ireland
2Mater Misericordiae University Hospital, Eccles St, Dublin , Ireland
Introduction
During the period 2005 to 2008, a study to assess the radiation doses received by the Irish population was carried out by RPII. This study was published in 2008 as the ‘Radiation Doses Received by the Irish Population’ report. In 2013 and 2014 this assessment was updated and focussed on a number of areas which have been identified as either liable to have changed in the interim period (e.g., medical doses) or for which there had been a lack of Irish data for use in the previous assessment (e.g., natural radioactivity in foodstuffs).
Approach
The assessment considered the following sources of radiation exposure/dose pathways:
Exposure to external radiation (including cosmic radiation at sea level and gamma dose from natural and artificial radioactivity in soils);
Exposure to cosmic radiation due to air travel;
Exposure to radon in homes;
Exposure to thoron from building materials;
Exposure to natural and artificial radioactivity in the diet;
Exposure to natural and artificial radioactivity at work;
Medical exposure of patients.
The following new data will be included in the new report that were not available in 2008:
Results from a new RPII study on radioactivity in the Irish diet, including measurements of the radioisotopes lead-210 and radium-226 in food.
Data from a more comprehensive study to measure thoron and its decay products in Irish homes.
A more detailed evaluation of medical exposures based on comprehensive surveys by the Irish Health Service Executive (HSE) which included a wider range of procedures in modalities such as CT, Interventional, General X-ray and Nuclear Medicine.
Results
The estimated average annual dose in Ireland from all sources of radiation of 4,037 µSv is consistent with the value of 3,950 µSv which was estimated in the previous assessment.
The average annual doses estimated in this study and those reported in 2008 for each exposure pathway are summarised in Table 1 and illustrated in Figure 1.
The same data are presented in Figure 2 as a percentage of the total average annual dose. Overall, natural radiation pathways account for 86% (3,480 µSv) of all radiation exposures in Ireland and the bulk of the remainder is due to diagnostic medical exposure of patients. Other artificial sources make a very small contribution to the average annual dose.
The slight increase in the total average annual dose observed (2%) is mainly due to the increase in the estimate of the average annual dose from thoron (increase from 280 µSv in 2008 to the current value of 350 µSv). This is as a result of using more recent and updated dose conversion coefficients, rather than resulting from increased thoron levels. The estimated doses from exposure to radioactivity contained in food and from radon in above ground workplaces also increased slightly. These increases are primarily due to the availability of additional or more comprehensive data than in 2008.
Figure 1. Estimated average annual doses in Ireland (µSv)
Table 1. Comparison of average annual doses in Ireland (µSv) from 2008
and 2014 studies
Figure 2. Distribution of average annual radiation doses in Ireland
Exposure pathway
2008
2014
Cosmic radiation
345
343
Gamma radiation in the environment
310
301
Radon in homes
2050
1995
Thoron in homes
280
350
Radioactivity in food
240
267
Occupational exposures (including radon in workplaces)
185
235
Medical exposures
540
546
TOTAL
3950
4037