Influence of soil structure on the "Fvapproach" applied to238U and226Ra.
The soil-to-plant transfer factors were determined in a granitic area for the two long-lived uranium series radionuclides238U and226Ra. With the aim to identify a physical fraction of soil whose concentration correlates linearly with the plant concentration, the soil compartment was analyzed in various stages. An initial study identified the soil compartments as being either bulk soil or its labile fraction. The bulk soil was subsequently divided into three granulometric fractions consisting of: coarse sand, fine sand, and silt and clay. The soil-to-plant transfer of radionuclides for each of these three texture fractions was analyzed. Lastly, the labile fraction was extracted from each textural part, and the activity concentration of the radionuclides238U and226Ra was measured. In order to assess the influence of soil texture on the soil-to-plant transfer process, we sought to identify possible correlations between the activity concentration in the plant compartment and those found in the different fractions within each soil compartment. The results showed that the soil-to-plant transfer process for uranium and radium depends on soil grain size, where the results for uranium showed a linear relationship between the activity concentration of uranium in the plant and the fine soil fraction. In contrast, a linear relation between the activity concentration of radium in the plant and the soil coarse-sand fraction was observed. Additionally, the presence of phosphate and calcium in the soil of all of the compartments studied affected the soil-to-plant transfer of uranium and radium, respectively.
Grupo de Radiactividad Natural, Universidad de Extremadura, 06071 Badajoz, Spain.
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Blanco Rodríguez
Grupo de Radiactividad Natural, Universidad de Extremadura, 06071 Badajoz, Spain. Electronic address: fvt@unex.es.
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Vera Tomé
Laboratorio de Radiaciones Ionizantes, Universidad de Salamanca, 37008 Salamanca, Spain.
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Lozano
D019659:Asteraceae / Q000378:metabolism; D007887:Fabaceae / Q000378:metabolism; D010944:Plants / Q000378:metabolism* / Q000528:radiation effects; D006109:Poaceae / Q000378:metabolism; D011883:Radium / Q000032:analysis* / Q000378:metabolism; D012822:Silicon Dioxide / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D012990:Soil Pollutants, Radioactive / Q000009:adverse effects / Q000032:analysis* / Q000378:metabolism; D014501:Uranium / Q000032:analysis* / Q000378:metabolism
D012987:Soil; D012990:Soil Pollutants, Radioactive; C007886:granite; D014501:Uranium; D012822:Silicon Dioxide; D011883:Radium
Availability; Radium; Soil-to-plant transfer; Textural fractions; Uranium