Evaluation of the variation of ²²⁶Ra and Ca uptake by plant and their relationship

Abstract

The transfer of 226Ra from soil to plant has been studied for wild trees and grasses to identify the site-and the plant-s~ecific variability in relation to the transfer of Ca. Twelve species of plants and soils were sampled from three different forests and one flood plain in Okayama, Japan. The concentrations of 226Ra in plant varied about 60 times by species and sites, while those in soil were not different significantly among sites. The transfer factors defmed as~e concentration ratio of 226Ra between plant and soil were linearly correlated with that of Ca, implying that~he abI1~ty of Ca uptake b~plant r~f1ect the ability of 226Ra uptake. The Ca concentrations in plant showed spe~le~-.speclfic value and vaned 22 tImes. The range of transfer factor (plant/soil) for Ca increased by the vanablhty of the Ca concentration in soil among sites. These results suggest that the wide variability of 226Ra concentration in plant can be ascribed to both the differences in plant and soil factors of Ca concentration. K1!YWORDS

Fe, Mn and 238U Accumulations in Phragmites australis Naturally Growing at the Mill Tailings Pond; Iron Plaque Formation Possibly Related to Root-Endophytic Bacteria Producing Siderophores

“…ex Steud. have been found to grow naturally [9]. P. australis, a wetland plant, is distributed globally, especially in Asia and Europe, from cold temperate regions to hot humid tropical wetlands [6,10].…”

“…P. australis forms vertical and horizontal rhizomes and develops aerenchyma to transport atmospheric oxygen to the roots [11,12]. In addition, P. australis has been reported to be used in artificial wetlands to treat metal wastewater because it accumulates heavy metals and radionuclides in roots [6,7,9,13,14]. Generally, plants accumulating high concentrations of metals should have metal-tolerance mechanisms because such high concentrations cause toxicity to plants [15].…”