Soil to plant transfer of 238U 226Ra and 232Th on a uranium mining-impacted soil from southeastern China

Both soil and plant samples of nine different plant species grown in soils from southeastern China contaminated with uranium mine tailings were analyzed for the plant uptake and translocation of U-238, Ra-226 and Th-232. Substantial differences were observed in the soil-plant transfer factor (TF) among these radionuclides and plant species. Lupine (Lupinus albus) exhibited the highest uptake of U-238 (TF value of 3.7 x 10(-2)), while Chinese mustard (Brassica chinensis) had the least (0.5 x 10(-2)). However, in the case of Ra-226 and Th-232, the highest TFs were observed for white clover (Trifolium pratense) (3.4 x 10(-2)) and ryegrass (Lolium perenne) (2.1 x 10(-3)), respectively. Th-232 in the tailings/soil mixture was less available for plant uptake than Ra-226 or U-238 and this was especially evident for Chinese mustard and corn (Zea mays). The root/shoot (R/S) ratios obtained for different plants and radionuclides shown that Indian mustard had the smallest R/S ratios for both Ra-226 (5.3 +/- 1.2) and Th-212 (5.3 +/- 1.7), while the smallest R/S ratio for U-238 was observed in clover (2.8 +/- 0.9). (c) 2005 Elsevier Ltd. All rights reserved.