Phytoextraction of uranium and thorium by native trees in a contaminated wetland
The phytoremediation potential of native trees in a U and Th contaminated wetland was examined. Based on measurements of the annual biomass of leaves and their contaminant concentrations, we estimated the reduction in soil contamination over time. Significant differences among tree species were found, with tupelo (<Emphasis Type=”Italic”>Nyssa sylvatica</Emphasis>) and sweetgum (<Emphasis Type=”Italic”>Liquidambar styraciflua</Emphasis>) having a significantly greater capacity to remove U and Th from the soil than the other tree species. More U was phytoextracted than Th from the site. Phytoextraction rate constants were developed and revealed that although U and Th phytoextraction was exceptionally high at the site, an order of magnitude greater than predicted, the community of native trees would lower the soil inventory of <Superscript>238</Superscript>U and <Superscript>232</Superscript> Th by only 1% over the next 100 years.
KeywordsUranium Thorium Phytoremediation Native Tree Contaminant Concentration
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