Nuclear Energy for New Europe 2009

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No: 1011

Conference: Nuclear Energy for New Europe 2009

Title: Natural radionuclides in milk from the vicinity of a former uranium mine

Theme: Radiation and Environment

Author(s): Marko Štrok, Borut Smodiš

Contact : Marko Štrok

E-mail: marko.strok@ijs.si

Address: Institut "Jožef Stefan" O2
1001 Ljubljana

Country: Slovenia

Four milk samples were collected from farms in the vicinity of former uranium mine Žirovski vrh and one from reference location. In the milk samples, 238U, 234U, 226Ra, 210Pb and 210Po were determined.
Samples were evaporated to dryness. For the analysis of uranium and 226Ra, samples were ashed at 650 °C. Then 232U and 133Ba tracers were added in order to determine chemical recovery. After that, samples were digested with HNO3, HCl and H2O2, evaporated to dryness and dissolved in diluted HNO3. H2SO4 and Pb were added in order to precipitate Ra from the solution. After centrifugation, solution was decanted and stored for subsequent uranium separation. The precipitate was dissolved with NaOH and EDTA. After the dissolution, Ba ions, pH indicator, acetic acid, Na2SO4 and BaSO4 were added in order to microprecipitate Ra as Ba(Ra)SO4. Counting source was prepared by filtrating Ra microprecipitate through a 0.1 µm filter. Uranium was separated from other radionuclides on UTEVA separation column and microprecipitated with NdF3. Counting source was prepared by filtrating through a 0.1 µm filter. For the analysis of 210Pb and 210Po, 209Po and Pb tracers were added to the dried samples to determine chemical recovery. Then the samples were digested with HNO3, HCl and H2O2. Residue remaining after the digestion was filtered away and the solution was evaporated to dryness and dissolved in 2 M HCl. 210Pb and 210Po were separated on Sr separation resins. The counting source for 210Pb was prepared by precipitating Pb with addition of H2SO4. 210Po was spontaneously deposited on a Cu disc. Uranium, 226Ra and 210Po were measured by alpha spectrometric system equipped with PIPS (passivated implanted planar silicon) detectors and 210Pb by a gas flow proportional counter.
Activity concentrations varied from 0.0011 – 0.021 Bq/kg fresh weight for 238U, 0.0025 – 0.012 Bq/kg fresh weight for 234U, 0.011 – 0.013 Bq/kg fresh weight for 226Ra, 0.044 – 0.060 Bq/kg fresh weight for 210Pb and 0.031 – 0.065 Bq/kg fresh weight for 210Po.
In conclusion, analytical problems encountered in radiochemical determinations are discussed and effective ingestion doses for different population groups assessed.

No:	1011
Conference:	Nuclear Energy for New Europe 2009
Title:	Natural radionuclides in milk from the vicinity of a former uranium mine
Theme:	Radiation and Environment
Author(s):	Marko Štrok, Borut Smodiš
Contact :	Marko Štrok
E-mail:	marko.strok@ijs.si
Address:	Institut "Jožef Stefan" O2 1001 Ljubljana
Country:	Slovenia

Four milk samples were collected from farms in the vicinity of former uranium mine Žirovski vrh and one from reference location. In the milk samples, 238U, 234U, 226Ra, 210Pb and 210Po were determined. Samples were evaporated to dryness. For the analysis of uranium and 226Ra, samples were ashed at 650 °C. Then 232U and 133Ba tracers were added in order to determine chemical recovery. After that, samples were digested with HNO3, HCl and H2O2, evaporated to dryness and dissolved in diluted HNO3. H2SO4 and Pb were added in order to precipitate Ra from the solution. After centrifugation, solution was decanted and stored for subsequent uranium separation. The precipitate was dissolved with NaOH and EDTA. After the dissolution, Ba ions, pH indicator, acetic acid, Na2SO4 and BaSO4 were added in order to microprecipitate Ra as Ba(Ra)SO4. Counting source was prepared by filtrating Ra microprecipitate through a 0.1 µm filter. Uranium was separated from other radionuclides on UTEVA separation column and microprecipitated with NdF3. Counting source was prepared by filtrating through a 0.1 µm filter. For the analysis of 210Pb and 210Po, 209Po and Pb tracers were added to the dried samples to determine chemical recovery. Then the samples were digested with HNO3, HCl and H2O2. Residue remaining after the digestion was filtered away and the solution was evaporated to dryness and dissolved in 2 M HCl. 210Pb and 210Po were separated on Sr separation resins. The counting source for 210Pb was prepared by precipitating Pb with addition of H2SO4. 210Po was spontaneously deposited on a Cu disc. Uranium, 226Ra and 210Po were measured by alpha spectrometric system equipped with PIPS (passivated implanted planar silicon) detectors and 210Pb by a gas flow proportional counter. Activity concentrations varied from 0.0011 – 0.021 Bq/kg fresh weight for 238U, 0.0025 – 0.012 Bq/kg fresh weight for 234U, 0.011 – 0.013 Bq/kg fresh weight for 226Ra, 0.044 – 0.060 Bq/kg fresh weight for 210Pb and 0.031 – 0.065 Bq/kg fresh weight for 210Po. In conclusion, analytical problems encountered in radiochemical determinations are discussed and effective ingestion doses for different population groups assessed.