Climate change - mediated atmospheric ²¹⁰Po and ²¹⁰Pb distribution: How significant can it be for the inhalation dose to humans?

Abstract

The concentration of ²¹⁰Po and ²¹⁰Pb in vegetation, and their transfer from soil to vegetation and via aerosol deposited on foliage are well established. The available data show significantly higher levels of these radionuclides in ash from forest fires and aerosols downwind from industrial sites. The climate change-induced hot and dry conditions promote the spread of forest fires, which burn huge areas. On average, over 10 million hectares are reportedly lost annually. Large-scale forest fires and fossil-fuel and coal-operated Power and Desalination Plants are very likely to result in the dispersion of ²¹⁰Pb and ²¹⁰Po into the regional aerosol; such an effect has already been observed due to fires in Ukraine, Belarus, and Russia, which have led to the dispersion of ¹³⁷Cs over large parts of Europe. We have measured elevated levels in Kuwait, and similar observations have been reported from Portugal. The higher levels of ²¹⁰Po in PM_2.5 raise a serious concern about an increased inhalation dose humans could receive. Our estimate shows that humans in areas affected by forest fires might receive a dose equivalent to 2 µSv d^-1, which is significantly higher than 0.099 µSv d^-1, the dose a person gets from smoking a packet of cigarettes daily. We propose that size-fractionated aerosol sampling should be taken up in regions affected by forest fires and industrial activities that add ²¹⁰Po to the atmosphere in order to obtain a robust inhalation dose assessment and issue informed advisories to the public.

Keywords

Forest fires / ²¹⁰Po / ²¹⁰Pb / size-fractionated aerosol / inhalation / dose / PM_2.5

References

[1] Baskaran M. Radon: a tracer for geological, geophysical and geochemical studies. Springer Cham; 2016. p. 260.

[2] Długosz-Lisiecka M.Excess of ²¹⁰polonium activity in the surface urban atmosphere. Part (1) fluctuation of the ²¹⁰Po excess in the air.Environ Sci Process Impacts2015;17:458-64

[3] Długosz-Lisiecka M.The sources and fate of ²¹⁰Po in the urban air: A review.Environ Int2016;94:325-30

[4] UNSCEAR report. Sources, effects and risks of ionizing radiation. Available from: https://www.unscear.org/unscear/en/publications/1988.html [Last accessed on 27 Dec 2023]

[5] Poet SE,Martell EA.Lead 210, bismuth 210, and polonium 210 in the atmosphere: Accurate ratio measurement and application to aerosol residence time determination.J Geophys Res1972;77:6515-27

[6] Papastefanou C.Mean residence times of atmospheric aerosols in the boundary layer as determined from 210Bi/210Pb activity ratios.J Aerosol Sci1991;22:927-31

[7] Peirson DH,Spicer GS. Lead-210 and polonium-210 in the atmosphere. Available from: http://www.gammaexplorer.com/wp-content/uploads/2014/03/9381-31656-1-PB.pdf [Last accessed on 27 Dec 2023]

[8] Nevissi A,Kuroda PK.Long-lived radon daughters as atmospheric radioactive tracers.Health Phys1974;27:181-8

[9] Semertzidou P,Appleby PG.Atmospheric residence time of ²¹⁰Pb determined from the activity ratios with its daughter radionuclides ²¹⁰Bi and ²¹⁰Po.J Environ Radioactiv2016;160:42-53

[10] Baskaran M.Po-210 and Pb-210 as atmospheric tracers and global atmospheric Pb-210 fallout: a review.J Environ Radioact2011;102:500-13

[11] Carvalho FP.Origins and concentrations of ²²²Rn, ²¹⁰Pb, ²¹⁰Bi and ²¹⁰Po in the surface air at Lisbon, Portugal, at the Atlantic edge of the European continental landmass.Atmospheric Environment1995;29:1809-19

[12] Ram K.Atmospheric ²¹⁰Pb, ²¹⁰Po and ²¹⁰Po/²¹⁰Pb activity ratio in urban aerosols: temporal variability and impact of biomass burning emission.Tellus B: Chemical and Physical Meteorology2012;64:17513

[13] Yi Y,Liu G.Atmospheric deposition fluxes of ⁷Be, ²¹⁰Pb and ²¹⁰Po at Xiamen, China.J Radioanal Nucl Chem2007;273:157-62

[14] Carvalho FP,Malta M.Vegetation fires and release of radioactivity into the air.WIT Trans Biomed Health2011;15:3-9.

[15] Carvalho FP,Malta M. Exposure to forest fires, radioactivity and health risks. 8th International Symposium on Occupational Safety and Hygiene (SHO); 2012 126-130. Available from: https://hero.epa.gov/hero/index.cfm/reference/details/reference_id/2648989 [Last accessed on 22 Dec 2023]

[16] Uddin S,Behbehani M.²¹⁰Po in the environment: reassessment of dose to humans.Sustainability2023;15:1674

[17] Carvalho FP,Malta M.Exposure to radionuclides in smoke from vegetation fires.Sci Total Environ2014;472:421-4

[18] Behbehani M,Uddin S.Enhanced polonium concentrations in aerosols from the gulf oil producing region and the role of microorganisms.Int J Environ Res Public Health2021;18:13309 PMCID:PMC8705287

[19] Behbehani M,Baskaran M.²¹⁰Po concentration in different size fractions of aerosol likely contribution from industrial sources.J Environ Radioact2020;222:106323

[20] UNSCEAR. Sources and effects of ionizing radiation. Available from: https://www.unscear.org/unscear/en/publications/2008_1.html [Last accessed on 22 Dec 2023]

[21] Eckerman K,Menzel H.ICRP publication 119: compendium of dose coefficients based on ICRP publication 60.Ann ICRP2013;42:1-130

[22] Evangeliou N,Cozic A,Møller AP.Wildfires in chernobyl-contaminated forests and risks to the population and the environment: a new nuclear disaster about to happen?.Environ Int2014;73:346-58

[23] Bae MS,Lee KY,Kim YJ.Long-range transport of biomass burning emissions based on organic molecular markers and carbonaceous thermal distribution.Sci Total Environ2014;466-467:56-66

[24] MacCarthy J,Tyukavina S,Harris N. The latest data confirms: forest fires are getting worse. Available from: https://www.wri.org/insights/global-trends-forest-fires [Last accessed on 22 Dec 2023]

[25] Kim G,Jang J,Hwang DW.Evidence for anthropogenic ²¹⁰Po in the urban atmosphere of Seoul, Korea.Environ Sci Technol2005;39:1519-22

[26] Tadmor J.Radioactivity from coal-fired power plants: a review.J Environ Radioactiv1986;4:177-204

[27] Długosz-Lisiecka M.Excess of polonium-210 activity in the surface urban atmosphere. Part 2: origin of ²¹⁰Po excess.Environ Sci Process Impacts2015;17:465-70

[28] Suzuki T,Nakayama N,Ohta K.Measurement of the ²¹⁰Po/²¹⁰Pb activity ratio in size fractionated aerosols from the coast of the Japan sea.Atmospheric Environment1999;33:2285-8

[29] Behbehani M. Atmospheric concentrations of ²¹⁰Pb, ²¹⁰Bi and ²¹⁰Po in Kuwait. Available from: http://kdrviewer.kisr.edu.kw/BookViewer/?book_id=7205&keyword=Atmospheric%20Concentrations%20of%20210Pb,%20210Bi%20and%20210Po%20in%20Kuwait [Last accessed on 22 Dec 2023]

[30] Carvalho FP. Tobacco smoking, indoor exposure and the lung radioactivity. Proceedings of the SHO2009: International Symposium on Occupational Safety and Hygiene; Guimaraes, Portugal. 5–6 February 2009; pp. 131–135.

[31] Uddin S,Fowler SW,Dupont S.Assessment of loss of ²¹⁰Po from fish and shrimp by cooking and its effect on dose estimates to humans ingesting seafood.J Environ Radioact2019;205-6:1-6

[32] Carvalho FP.Polonium in cigarette smoke and radiation exposure of lungs.Czech J Phys2006;56:D697-703

[33] Uddin S,Fowler SW.Aerosols as vectors for contaminants: a perspective based on outdoor aerosol data from Kuwait.Atmosphere2023;14:470

[34] Carvalho FP,Malta M.Radioanalytical assessment of environmental contamination around non-remediated uranium mining legacy site and radium mobility.J Radioanal Nucl Chem2014;299:119-25.

[35] Church T,Baskaran M.Intercalibration studies of ²¹⁰Po and ²¹⁰Pb in dissolved and particulate seawater samples.2012;10:776-89

[36] Du J,Baskaran M,Huang D.Temporal variations of atmospheric depositional fluxes of ⁷Be and ²¹⁰Pb over 8 years (2006-2013) at Shanghai, China, and synthesis of global fallout data.JGR Atmospheres2015;120:4323-39

[37] Simon SL.The plant/soil concentration ratio for calcium, radium, lead, and polonium: Evidence for non-linearity with reference to substrate concentration.J Environ Radioactiv1987;5:123-42

[38] Ibrahim S.Plant accumulation and plant/soil concentration ratios of 210Pb and 210Po at various sites within a uranium mining and milling operation.Environ Exp Bot1987;27:203-13

[39] Whicker FW. Radioecology: nuclear energy and environment. Available from: https://inis.iaea.org/Search/searchsinglerecord.aspx?recordsFor=SingleRecord&RN=15009266 [Last accessed on 22 Dec 2023]

[40] Behbehani M,Al-Rashed Z. Atmospheric concentration of 210-Pb, 210-Bi, and 210-Po in Kuwait. Available from: https://www.researchgate.net/publication/343480947_Atmospheric_Concentration_of_210Pb_210Bi_and_210Po_in_Kuwait [Last accessed on 22 Dec 2023]

[41] Behbehani M,Habibi N. ²¹⁰Po in ultrafine aerosol particles and its likelihood to mutate the microbial community. http://kdrviewer.kisr.edu.kw/BookViewer/?book_id=8484&keyword=? [Last accessed on 22 Dec 2023]

[42] Wallneri G.Distribution of ²¹²Pb, ²¹⁴Pb and ²¹⁰Pb with its daughter products on aerosol fractions from Vienna and Badgastein (Austria)..Radiochimica Acta2001;89:791-8