DISTRIBUTION OF ISOTOPIC URANIUM IN BACCHARIS SALICIFOLIA COLLECTED IN A URANIUM´S RICH SOIL

It is well known that plants are excellent indicators of soil pollution. The objective of the study was to assess the behavior of isotopic uranium in Baccharis salicifolia. This plant is not directly involved in the human food chain; however, the information concerning the concentration levels and translocation of uranium contributed to understand the transfer mechanisms from plants to the human diet. The concentration of U-isotopes was determined by liquid scintillation, using a portable detector TRIATHLER, HIDEX OY. The plant sample was divided in root, stem, and leaves. Once separated, the samples were washed with distilled water to remove any trace of sediment or soil particles. Afterwards the samples were dried and calcined previously to radiochemical process used to isolate the uranium. The concentration average obtained in root, stem, and leaf were 19.0 Bq·Kg^-1, 20.7 Bq·Kg^-1, and 25.2 Bq·Kg^-1, respectively. The uranium concentration was higher in leaf than in stem and root. Uranium absorption by the plant is the same for ²³⁸U and ²³⁴U.