Plant Uptake of Radioactive Elements from Soils Contaminated by Uranium Mining Industry in Buhovo, Bulgaria

The aim of the present study was to determine the degree of accumulation in certain agricultural plants of uranium from soil collected from the bowl of Buhovo tailing pond near former uranium processing plant “Metallurg” in Bulgaria. The measured specific activities of uranium isotopes in soil were: 238U - 2489 Bq/kg, 235U - 117 Bq/kg and 234U - 2107 Bq/kg. Vessel vegetation trials were carried out with three varieties of barley (F-173, F-210, „Veslets”), triticale, chard, sorrel, arugula and maize on the collected soil. The highest soil to plant transfer coefficients were determined in leafy greens (238U: 2,53.10-3 - 5,97.10-3 ; 235U: 2,56.10-3 - 6,07.10-3 ; 234U : 2,96.10 -3 - 6,06.10-3 ), lower in cereals (238U: 1,32.10-3 - 1,99.10-3 ; 235U: 1,50.10-3 - 2,09.10-3 ; 234U : 1.57.10-3 - 2.49.10-3 ) and the lowest in maize (238U: 0.50.10-3; 235U: 0.56.10-3 ; 234U: 0.59.10-3). For leafy plants, the transfer factors for arugula and chard were up to three times higher than those for sorrel. Comparing different barley varieties, up to 50% lower accumulation was found in barley F173 than in other varieties tested.