NUKLEONIKA 2010, 55(2):187-193

 


POLONIUM (210Po) AND URANIUM (234U, 238U) IN WATER, PHOSPHOGYPSUM AND THEIR BIOACCUMULATION IN PLANTS AROUND PHOSPHOGYPSUM WASTE HEAP AT WIŚLINKA (NOTHERN POLAND)



Bogdan Skwarzec, Alicja Boryło, Alicja Kosińska, Sylwia Radzajewska

Faculty of Chemistry, University of Gdańsk, 18/19 Sobieskiego Str., 80-952 Gdańsk, Poland

The principal sources of polonium and uranium radionuclides the Wiślinka area waste dump are phosphorites and phosphogypsum produced by the Phosphoric Fertilizers Industry of Gdańsk. The values of uranium and polonium concentration in water with immediate surroundings of waste heap are considerably higher than in the waters of the Martwa Wisła river. The activity ratio 234U/238U is approximately about one in the phosphogypsum (0.97±0.06 and 0.99±0.04) and in the water of a retention reservoir and a pumping station (0.92±0.01 and 0.99±0.04), while in the water from the Martwa Wisła river is slightly higher than one (1.00±0.07 and 1.06±0.02). The leaching process of uranium and polonium from the phosphogypsum waste heap is responsible for the maximum uranium concentration (1097±6 µg·dm–3 and 1177±6 µg·dm–3) and the high 210Po concentration (131.4±0.9 mBq·dm–3 and 165.7±1.4 mBq·dm–3) in the retention reservoir. The major source of polonium and uranium in plants are wet and dry atmospheric falls gathering soil and air dust from the phosphogypsum waste dump and root system. The highest uranium and polonium concentrations were found in older part of grasses (yellow oatgrass, meadow foxtail, moneywort), exposed to atmospheric falls for a long time. The maximum concentrations of 210Po were characterized for samples of plant root collected at the retention reservoir (150.50±4.97 and 108.55±3.95 Bq·kg–1 dry mass). Polonium and uranium concentrations in water samples of the Martwa Wisła river are relatively low in comparison with the value in the retention reservoir and pumping station near the phosphogypsum waste heap. This suggests that the radionuclides could be leached from the dumping site to the surrounding environment.

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