Phytoremediation of radiocesium-contaminated soil in the vicinity of Chernobyl, Ukraine

Remediation of soil contaminated with Cs-137 remains one of the most challenging tasks after the Chernobyl 1986 accident. The objectives of this research were to (1) identify extractants that may be used to solubilize Cs-137 in soil solution, (2) study the effect of soil amendments on Cs-137 accumulation by plants, and (3) evaluate the applicability of phytoextraction for environmental restoration of soil contaminated with Cs-137. Th, availability of Cs-137 to the plants in Chernobyl soil was limited, because this radionuclide was tightly bound to exchange sites of sail particles or incorporated into the crystalline structure of primary and secondary minerals. Out of 20 soil amendments tested to increase Cs-137 desorption/solubility in the soil, ammonium salts were found to be the most practical soil amendment that can potentially increase Cs-137 bioavailability. Among the screened plants, Amaranth cultivars had the highest Cs-137 accumulation. Three sequential crops of Indian mustard grown in one vegetation season at the experimental plot resulted in a small decrease of Cs-137 specific activity within the tap 15 cm of soil. Further improvements are necessary to make phytoremediation technology a feasible option for restoration of Cs-137-contaminated territories.