1 / 47

Polonium-210 and Lead-210 in the Terrestrial Environment :

Polonium-210 and Lead-210 in the Terrestrial Environment :. Polonium-210 and Lead-210 in the Terrestrial environment: A historical review. Bertil R.R. Persson 1 , Elis Holm 2.

juana
Télécharger la présentation

Polonium-210 and Lead-210 in the Terrestrial Environment :

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Polonium-210 and Lead-210 in the Terrestrial Environment:

  2. Polonium-210 and Lead-210 in the Terrestrial environment:A historical review.Bertil R.R. Persson 1, Elis Holm2 1Medical Radiation Physics, Lund University, SE 22185 Lund, Sweden2Norwegian Radiation Protection Authority, Østerås, Norway

  3. Natural origin of 210Po and 210Pb in the terrestrial environment 238U >234Th>234Pa>234U>230Th>226Ra>222Rn> Radon-222 originates from the decay of uranium-238 in the earth´s crust anddiffuses from soil to the atmosphere where it´s concentration decreases monotony by height. With a half-life of 3.82 d 222Rn decays to the short lived radon daughters: >218Po (RaA 3.10min)>214Pb (RaB 26.8 min) >214Bi (RaC 19.9 min)>214Po(RaC´164.3 µs). These decay products attach to airborne particles which deposit as dry and wet deposition on the earth´s surface. 218Po (RaA 3.10 min) is in radioactive equilibrium with 222Rn at about 5 m above surface and 214Pb(RaB 26.8 min) >214Bi (RaC 19.9 min)>214Po(RaC´164.3 µs) is in radioactive equilibrium with 222Rn at about 50 m. The concentration of the long lived decay products; 214Po> 210Pb ( RaD 22.20 a)>210Bi (RaE 5.01 d) > 210Po(RaF 138.4 d) >206Pb(stable)

  4. Deposition of 210Pb 210Po 222Rn in air Other release 210Pb 210Bi 210Po 218Po 214Pb 214Bi 214Po 222Rn 226Ra 230Th 234U 234Pa 234Th 238U Plants, Lichen, moss Soil / Water Animals Inhalation and dietary intake

  5. 218Po RnA 214Pb RnB 214Bi RnC 214Po RnC´ 7-2 Bq/m3 600 µBq/m3 210Pb RnD 210Bi RnE 210Po RnF 30 µBq/m3 Jacobi Biophysik l, 175--188 (i963)

  6. Atmospheric fallout of 210Po and 210Pb 218Po>214Pb>214Bi>214Po> 222Rn(3.82d) 210Pb(22.3 a)>210Bi(5 d) >210Po(140d) Residence time 5 -15 d Dry deposition and Wet deposition 238U decay chain 234Th>234Pa>234U>230Th>226Ra

  7. a) Harwell; b) Brotherswater; c) Miilford Haven; d) Lochnagar; e) Esthwaite; f) Liverpool

  8. Appleby: Frank Oldfield Special Issue: Fallout radionuclide dating

  9. 210Po and 210Pb in soil N. Karunakara et al. / J. Environ. Radioactivity 51 (2000) 349}362

  10. 210Po and 210Pbi n soil Data from [N. Karunakara et al. / J. Environ. Radioactivity 51 (2000) 349}362].

  11. 210Po is very immobile in soil and it is mostly • irreversibly sorbed on clay and organic colloids. • The amount of 210Po contained in the top layer of • uncultivated soil can be correlated with the amount • of precipitation • [N. Karunakara et al. / J. Environ. Radioactivity 51 (2000) 349}362]. • There is a close correlation between the 210Po • levels of soil and its organic substance . • [N. Karunakara et al. / J. Environ. Radioactivity 51 (2000) 349}362]. • 210Po activity values change depend on soil type • and texture.

  12. 210Po and 210Po in soil Clay particles < 0.002 mm Silt particles 0,002 - 0.06 mm Sand particles 0.06 - 2 mm Gravel particles 2 - 60 mm S. Akyil et al. / Journal of Hazardous Materials 157 (2008) 328–334

  13. S. Akyil et al. / Journal of Hazardous Materials 157 (2008) 328–334

  14. Median Bq /g Mean 50 Bq /g

  15. S. Akyil et al. / Journal of Hazardous Materials 157 (2008) 328–334

  16. 210Po and 210Pb in ground water

  17. 210Pb - 210Po in vegetation Uptake of radionuclides from soil to plant is characterized using a transfer factor (TF); TF is the ratio of radionuclide activity concentration per unit mass concentrations (Bq / kg) of plant (Cplant ) and soil (Csoil ) respectively. TF = Cplant / Csoil

  18. From experimental measurements of the transfer factor of the plant Spartinu densiflora in the Odiel march in Spain the following non-linear relationship was found for 210Po: TF = 2.456 [Csoil] -0.663 (R. Perianez and A. MartinezAguirre, 1997).

  19. Tobacco is aged for a period of 1 - 2 years between harvest and manufacture of Cigarettes . Tobacco is often fertilized with apatite which contains 210Pb and 210Po

  20. 210Po and 210Pb in tobacco a(USA)(T. C. Tso et al., 1964); b(USA)(T. C. Tso et al., 1966); c(NZ,USA)(L. P. Gregory, 1965); d(A. C. Peres and G. Hiromoto, 2002); e(Greece)(A. Savidou et al., 2006); f(Pakistan) (S. N. A. Tahir and A. S. Alaamer, 2008)

  21. 2.5 nSv/mBq if inhaled 210Po in smoke inhaled from a cigarette 10 ± 6 mBq 13±8 mBq 210Po per cigarette. Due to the different tobacco-burning temperatures of smoking (between 500 and 700ºC), 210Po sublime more or less into the smoke which is inhaled by the smoker (Martell, 1975). The fraction of 210Po contents of the ash 4 – 65% the filter <2% The level 210Po inhaled from each specific brand should be declared on the cigarette package.

  22. Former Surgeon General C. Everett Koop said on national television that radioactivity contained in tobacco leaves is probably responsible for most tobacco-related cancer. (National Center for Atmospheric Research, 1964; American Lung Assn.; Dr. Joseph R. DiFranza, U. of Mass. Medical Center; Reader’s Digest, March 1986; Surg. Gen. C. Everett Koop, 1990.)

  23. Polonium kills ??

  24. 210Po and 210Pb in mosses Mosses such as Polytrichum and Sphagnum have no uptake from soil but are occasionally submerged with surface water. Beard mosses Alectoria, however, might be contaminated by re-suspension from soil. Various moss samples were collected 1979-1980 around Lilljuhatten in Sweden. The min and max level of 210Po in Polytrichum was 300-960 Bq/kg dw, in Sphagnum 185-700 Bq/kg dw and in Alectoria 570-640 Bq/kg (E. Holm et al., 1981). 570-640 Bq/kg 300-960 Bq/kg dw Polytrichum commune Sphagnum girgensohnii 

  25. Peatlands or mires are wetland ecosystems that are characterised by the accumulation of organic matter, which is produced and deposited at a greater rate than it is decomposed, leading to the formation of peat Over 90% of peatlands are in the temperate and cold belt in the Northern Hemisphere. The remaining area is concentrated in tropical and sub-tropical latitudes, much of it under forest.

  26. 210Po and 210Pb in peat B. Holynska et al.The Science of the Total Environment 218(1998)239]248

  27. Stable lead mg /kg Depth / cm

  28. Persson , Holm and Lidén. OIKOS 25: 140-147. Copenhagen 1974

  29. 210Po and 210Pb in communities of lichen (Cladonia alpestris)

  30. Radiolead (210Pb) and stable lead in the lichen Cladonia alpestris OIKOS 25: 140-147. Copenhagen 1974

  31. a)(P. V. Ramzaev et al., 1969); b)(B. R. Persson, 1972); c)(Blanchar.R.l and J. B. Moore, 1970) ; d)(Z. Jaworowski, 1969); e)(R. B. Holtzman, 1966); f)(P. Kauranen and J. K. Miettinen, 1969); g)(Blanchar.Rl and J. B. Moore, 1969); h)(C. R. Hill, 1965); i)(P. Kauranen et al., 1971); j)(R. B. Holtzman, 1966); k)(P. Kauranen et al., 1971); l)(R. B. Holtzman and F. H. Ilcewicz, 1971); m)(L. Skuterud et al., 2005); n)(A. Ugur et al., 2004).

  32. 210Po and 210Pb in the food chain lichen-reindeer and man Lichen - reindeer - man 210Pb 240 Bq/kg d.w. 0,030 Bq/kg w.w. 0.070 Bq / kg w.w. 210Po 200 7 0.5

  33. 210Pb in reindeer bone

  34. 210Po and 210Pb in the food chain lichen-reindeer and man Mattsson and Persson 1971 EUR 4800

  35. Summary

  36. For the future 210Po research: European network of sampling stations for Rain - Peat core : Measurements of 7Be- 210Pb / 210Po and trace elements annually each quarter 210Po declaration on cigarette package? More studies on the effect of 210Po in smoking man Development of low temperature smoking with low 210Po content in the smoke More studies and modelling of the food chain: lichen - reindeer - man

  37. The End Thank you for Your attention

More Related