Plant availability of uranium in contaminated soil from Crucea Mine (Romania)

International audienceA study of uranium distribution in soils and plants was conducted over the Crucea area (northern Romania). The elements most susceptible to HNO3 extraction (more than 65%) are cobalt, copper, nickel, lead, and zinc; less extractable are elements such as barium, chromium, strontium, and vanadium. Uranium and thorium show a relatively high percentage of extraction, e.g., 50.7 and 55.7%, respectively. Generally, high correlation coefficients exist between total and partial extractions. The highest correlation coefficients (r > 0.90) are for uranium, cobalt, copper, nickel, lead, and zinc. Analyses of the forest vegetation indicated that, in general, uranium is preferentially concentrated in the roots, followed by the twigs and leaves. Higher values of uranium content in plant samples from Crucea ore deposit area may be correlated with higher uranium contents in the soil and rock samples from this area. The study indicates that fir Abies alba has higher uptake of uranium than any other vegetation species present in this area