Actinides
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Ostrowski 1980). Some bacteria strains (S. levorice) may adsorb relatively high
amounts of U from water, at pH 3.5 (Tsuruta 2004).
Rainwaters collected in Sweden during 1999 contain U at an average value of
0.0022 μg/L, within the range of 0.0008–0.0054 μg/L. Its wet deposition in Sweden
was 0.021 g/ha/yr (Eriksson 2001a). Annual deposition of U on soils of the agricultural region of Croatia is estimated to be 3.1 Bq/m 2 for 235 U and 67 Bq/m 2 for 238 U
(USGS 2011).
58.3.4 AIR
The mean uranium concentration in air of Europe is estimated to be 0.002 ng/m 3 and
increases up to about 0.5 ng/m 3 above the urban regions (Reimann and de Caritat
1998). Elevated amounts of U in air are associated mainly with coal combustion and
nuclear power plants, and are considered the most important risk to the environment and health. Volcanic eruptions are significant sources of U in the atmosphere.
Its contents in aerial dust in some industrial regions vary from <2 up to about 10 mg/kg
(Manecki and Skowroński vide Kabata-Pendias 2011). Limit values given by the
Agency for Toxic Substances and Disease Registry (ATSDR 2011) are 50 μg/m 3 for
soluble U compounds and 250 μg/m 3 for its insoluble compounds.
Mosses collected during the last century from the Central Barents region contain
U up to 0.45 mg/kg, whereas its content in mosses from Norway was up to 0.89 mg/kg
(Steinnes et al. vide Caritat et al. 2001).
58.3.5 PLANTS
Uranium contents in vegetable plants vary within the range (rounded) of 0.0014–
0.0025 mg/kg fresh weight (FW) and are higher than in fruits, 0.0004–0.0011 mg/kg
FW (Shtangeeva 2008). The mean U content in winter wheat grain is 0.0001 mg/kg
(Eriksson 2001a).
Among various native plants grown in the polluted area of the Northern Europe (Kola
Pennisula), U content was <0.005 mg/kg in crowberry (E. nigrum) and 0.034 mg/kg
in moss (H. splendens) (Reimann et al. 2001). Forest mushrooms (grown in Spain) may
contain elevated amounts of U, up to 2.0 mg/kg (Campos et al. 2012). Uranium contents
of pumpkin seed oil vary, depending on its geographic origin (median value, in mg/kg):
0.08 in Austria, 0.13 in Russia, and 0.42 in China (Bandoniene et al. 2013).
In regions with U ores, the contents of this element in some herbs increase up to the
range of 0.1–1 mg/kg (Kovalevskyj and Kovalevskaja 2010). Uranium content of netted
chain fern (W. areolata) from contaminated soil was 44 mg/kg, whereas its content of
this plant grown in greenhouse was 6.4 mg/kg. Use of this plant for phytoremediation
has been considered (Knox et al. 2008).
58.3.6 HUMANS
The total body burden of U in humans is 40 μg, of which 40% is in the muscles,
20% in the skeleton, 10% in the blood, 4% in the lungs, 1% in the liver, and 0.3% in
the kidney (WHO 2005b). However, there are also other estimations: the adult body