Spatial variation in the vulnerability of Norwegian Arctic counties to radiocaesium deposition.

Under the Arctic Monitoring and Assessment Programme (AMAP), studies have been undertaken to compare potential fluxes of radiocaesium via important food products. The results for three Norwegian Arctic counties are presented in this paper. The comparative importance of different foodstuffs in contributing to collective dose varies spatially due to differing rates of production and transfer. Although reindeer meat is an important contributor to the radiocaesium flux following a nuclear release, other food products such as cow milk and lamb have been identified as potentially important. Assuming an even deposition following a nuclear release the radiocaesium flux was estimated to be highest for reindeer meat in Finnmark and Troms, whereas cow milk gave the highest flux in Nordland. The total number, geographical distribution and diet composition of indigenous peoples within different Arctic regions is an important factor affecting individual and collective doses arising from a nuclear release. Finnmark has been shown to be the most vulnerable of the three counties because it has the highest flux of radiocaesium and the largest number of indigenous people. The potential contribution of foodstuffs which are known to readily accumulate radiocaesium needs further consideration, in particular, mushrooms, freshwater fish and berries.

Absorption of radiocaesium by sheep after ingestion of contaminated soils.

The absorption of 137Cs by sheep following ingestion of contaminated soil was studied using an established dual isotope method. Two agricultural soils were studied: an alluvial gley contaminated by discharges to the sea from the Sellafield Reprocessing Plant, and a lowland organic soil that had been artificially contaminated. Values of the true absorption coefficient of radiocaesium of 0.19 +/- 0.03 and 0.03 +/- 0.01, respectively, were obtained for these soils. This implies that availability of soil-associated radiocaesium for uptake following ingestion is up to about 20% of that when the activity is incorporated in vegetation. These results have been compared to estimates of availability made using an in-vitro approach described previously and found to be in good agreement. However, comparison with in-vitro data obtained for an upland peat indicated that absorption from some upland organic soils could be greater than from the lowland organic soil.