Potential health risks from radioactive contamination of saltmarshes in NW England.

The present study focuses on the detection of Sellafield-derived (137)Cs and (241)Am 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.

Luminescence quartz dating of lime mortars. A first research approach.

Lime mortars mixed with sand are well suited for connecting structural materials, like stones and bricks, due to the mechanical properties this material exhibits. Their extensive use in architectural and decorative works during the last 4000 years motivated the introduction of the 'Luminescence clock' for age determination of mortars. The same principles as for quartz optically stimulated luminescence (OSL) dating of sediments were applied for age estimation of a mortar fragment removed from a Byzantine church monument dated by archaeological means to 1050-1100 years ago (the first half of the 10th century). The OSL from the quartz was monitored under blue light stimulation and UV detection, using a single-aliquot-regenerative-dose protocol. The quartz-OSL dating of the mortar resulted in 870 +/- 230 a. TL polymineral fine grain dating was also performed on a brick fragment which was connected to the mortar, resulting in a TL age of 1095 +/- 190 a.