Potential health risks from radioactive contamination of saltmarshes in NW England

The present study focuses on the detection of Sellafield-derived 137Cs and 241Am in contaminated saltmarshes from North-West England, UK, with a view to assessing the radiological impacts from radioactivity stored within the sediment record. The surface activities from these radionuclides were found in the range between 73 and 851 Bq kg−1 whereas peak activities ranging from 383 to 12690 Bq kg−1 were found below the surface of the upper marsh at a depth of approximately 5-20 cm. Potential radioactive exposure to humans from these highly active radionuclides comes mainly from direct exposure and resuspended dust inhalation for different saltmarsh users, which may be exacerbated by the remobilisation of radionuclides resulting from saltmarsh erosion. The total annual minimum, maximum and 'best estimate' doses ranging from 11 to 972 μSv y−1, fall below the ICRP-recommended annual dose limit, but the highest estimated total effective dose (972 μSv y−1) for a marsh user falls within 97% of the recommended dose limit and the highest 'best estimate' total annual doses of 110 and 307 μSv y−1 for Dee estuary and Biggar marshes, respectively, are almost 3 and 4 times higher than the estimated doses that are based on existing surface activities.