Naturally occurring radionuclides (NOR) and rare earth elements (REE) in soil and cereals in a high background area, Fen complex, Norway.

Some areas of the world have high natural background levels of naturally occurring radionuclides (NOR) and/or rare earth elements (REE). With high background radiation risk, knowledge about, for example, uptake by crops is required in the process of assessing radiation doses to humans. In the Fen complex, in Norway, underlying bedrock has elevated levels of both NOR and REE. In Mining hill where these bedrocks surface and there are also legacy mines, soils also have high background levels. Most of Fen complex is, however, covered by thick Holocene deposits but some of its agricultural soils are situated near the areas of surfacing carbonatite bedrock and legacy mines. We assess whether there has been any influence on the levels in the agricultural soils within the Fen complex from the areas with high NOR and REE soil background. We also determine uptake from soils by cereals into grain or grain with hull, and present concentration ratios (CR) for NOR and REE in this high background area. In particular, the REE CRs are an important augmentation to existing sparse datasets. We furthermore assess whether uptake can be biased by any soil particles adhering to cereal grain or grain with hull. We investigate whether washing (or not washing) and use of different acids for dissolution may affect ICP-MS results on common elements. We also address soil mass in cereal samples using Scandium and Titanium as tracers for soil particles and assess the potential magnitude of bias CR.