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Natural Uranium and Thorium Distributions in Podzolized Soils and Native Blueberry
Author(s) -
Morton L. S.,
Evans C. V.,
Estes G. O.
Publication year - 2002
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2002.1550
Subject(s) - bioavailability , cycling , soil water , vaccinium , thorium , radionuclide , chemistry , environmental chemistry , uranium , nuclide , plant tissue , botany , biology , ecology , bioinformatics , materials science , physics , archaeology , quantum mechanics , metallurgy , history
ABSTRACT Plant uptake of radionuclides is one of many vectors for introduction of contaminants into the human food chain. Thus, it is critical to understand soil–plant relationships that control nuclide bioavailability. Our objectives in this study were to (i) determine the extent of U and Th uptake and cycling by blueberry ( Vaccinium pallidum Aiton) in native habitat and (ii) identify the soil properties and processes that contribute most to U and Th bioavailability in this system. We collected composite samples of plant leaves and stems, and samples from surface (AE) horizons and from the upper part of the Bs horizon at two sites. Concentration ratios (CRs) for U and Th were calculated for all plant tissues, using both the AE and Bs horizons as the base. Soil concentrations of U ranged from 16 to 25 μg g −1 , with a mean of 21.1 μg g −1 Soil concentrations of Th ranged from 14 to 97 μg g −1 , with a mean of 41.8 μg g −1 Mean U concentrations were 8.65 × 10 −3 μg g −1 in leaf tissue, and 7.95 × 10 −3 μg g −1 in stem tissue. Mean Th concentrations were 1.59 × 10 −1 μg g −1 in leaf tissue, and 9.10 × 10 −2 μg g −1 in stem tissue. Blueberry plants are cycling both U and Th in this system, with Th cycling occurring to a greater extent than U. In addition, Th was translocated preferentially to plant leaves while U concentrations showed little preferential translocation. Uranium uptake, however, seemed more sensitive than Th uptake to soil properties.