Accumulation of radioiodine from aqueous solution by hydroponically cultivated sunflower (Helianthus annuus L.)

The suitability of sunflower plants (Helianthus annuus L.) for the phytoremediation of soils and waters contaminated with radioactive iodine was tested following the I-125 uptake from a hydroponic medium and translocation during 32-day cultivation. The plants accumulated about 26% of the applied activity in case of combination of I-125 (1.3 MBq) and 0.1 mM (KI)-I-127 ("carrier I-125") and 47% when only I-125 (1.3 MBq, "non-carrier I-125") was added. When hydroponic medium was changed for the fresh one every 4 days, the plants accumulated up to 59% of starting activity of non-carrier I-125. The I-125 distribution within the plant was followed using autoradiography. At low iodine level (non-carrier I-125) the radionuclide was localized mainly in the roots. At high iodine concentrations (carrier I-125) it was found mainly in the upper part of sunflower plants. All iodine removed from the liquid medium was found in the plant body., Volatilization of iodine (in the form of 10 or volatile organic compounds) apparently did not occur during accumulation and translocation. The achieved results indicate that sunflower can be used for phytoremediation of radioactive iodine, even if it is not its hyperaccumulator. (c) 2005 Elsevier B.V. All rights reserved.