Hydroponic uptake studies were conducted to evaluate the uptake and translocation of 99Tc, 133Cs (stable analog for 137Cs), 237Np, and 238U into established and seedling Andropogon virginicus specimens under controlled laboratory conditions. Plant specimens were grown in analyte-spiked Hoagland nutrient solution for 24 h, 3 d, and 5 d. Translocation to shoots was greatest for 99Tc and 133Cs, likely due to their analogous nature to plant nutrients, while 238U (and 237Np to a lesser extent) predominantly partitioned to root tissue with less extensive translocation to the shoots. Plant age contributed significantly to differences in concentration ratios for all nuclides in shoot tissues (p ≤ 0.024), with higher concentration ratios for seedling specimens. Additionally, duration of exposure was associated with significant differences in concentration ratios of 133Cs and 99Tc for seedlings (p = 0.007 and p = 0.030, respectively) while plant part (root or shoot) was associated with significant differences in concentration ratios of established plants (p < 0.001 for both nuclides). Statistically significant increases in radionuclide uptake in seedling specimens relative to established plants under controlled conditions suggests that, in addition to geochemical factors, plant life stage of wild grasses may also be an important factor influencing radionuclide transport in the natural environment.
1Department of Environmental Engineering and Earth Science, Clemson University, 342 Computer Ct., Anderson, SC 29625;
2Department of Plant and Environmental Science, 111 Biosystems Research Complex (BRC), Clemson University, Clemson, SC 29634.
The authors declare no conflicts of interest.
For correspondence contact: Dawn A. Montgomery, Department of Environmental Engineering and Earth Science, Clemson University, 342 Computer Ct., Anderson, SC 29625, or email at email@example.com.
(Manuscript accepted 28 December 2017)
Mrs. Dawn Montgomery is a third year PhD student studying Environmental Engineering and Earth Science with emphasis on Environmental Health Physics and Radioecology at Clemson University. Her current research is focused on plant uptake of various radioactive contaminants and the associated roll that plants have on the transport of those contaminants in the environment. Additionally, she is interested in dosimetric modeling of non-human biota and has developed several phantoms for the grass species used in her uptake experiments and stylized phantoms for an adult duck and a duckling.