Radon "Why is it so Dangerous?"
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Radon gas is the second leading cause of lung cancer after smoking. It is a colorless, odorless, naturally occurring radioactive gas that forms from the decay of uranium in soil and rocks. High levels of radon exposure can damage lung tissue and lead to lung cancer through DNA damage and cell death caused by its radioactive decay, which produces alpha particles. The main methods for detecting radon involve measuring its decay products over either short or long periods of time. Mitigation strategies aim to prevent radon from entering homes through sealing and ventilation techniques.
Radon "Why is it so Dangerous?"
- 1. “Why is it so dangerous?” RADON GAS Shamail Ahmed
- 2. PREVIEW • Statistics and Motivation • Radioactivity • Chemistry of Radon • Sources, transport mechanism and distribution of Radon • Toxicity, DNA Damage and Cell death • Detection and Mitigation 2
- 3. MOTIVATION & STATISTICS 1. Radon, C.I. (2015) Radon facts and myths to keep your home and family save. Available at: http://www.centraliaradon.com/radon-facts-and-myths/ (Accessed: 5 November 2016). 2. EPA, U. and ORIA (2016) Health risk of radon. Available at: https://www.epa.gov/radon/health-risk-radon (Accessed: 5 November 2016). 3. Stoker, S.H. (2008) General, organic, and biological chemistry, 5th edition. 5th edn. Boston, MA, United States: Brooks/Cole Cengage Learning. 3 • Biggest cause of lungs cancer after Smoking. • Almost everyone is exposed to some extent.
- 4. RADIOACTIVITY & RADIOACTIVE RADIATIONS 1. Power, N., Physics, R. and Dosimeter, P. (2016) Radioactive decay - nuclear power. Available at: http://www.nuclear-power.net/nuclear-power/reactor-physics/atomic- nuclear-physics/radioactive-decay/ (Accessed: 5 November 2016). 2. Bennett, L. (2012) Nuclear chemistry. Available at: http://edtech2.boisestate.edu/lindabennett1/502/nuclear%20chemistry/types%20of%20decay.html (Accessed: 5 November 2016). 4 λ < 0.01 nm
- 5. PROPERTIES OF RADIOACTIVE RADIATIONS 1. Pearson, N. (2016) Nuclear decay definition. Available at: http://chemistry.tutorvista.com/nuclear-chemistry/nuclear-decay.html (Accessed: 5 November 2016). 5 Speed 6% of c 98% of c 100% of c
- 6. IMPORTANT TERMINOLGIES AND UNITS 6 One Decay Process Half-Life When N/No=1/2 1 picoCurie = 0.037 becquerel 1 Ci = 3.7 × 10¹⁰ decays per second Other Decay Processes include, Chain of ‘n’ numbers of decays, parallel decay etc. 1 pCi/L = 37 Bq/cub. meter
- 7. CHEMISTRY OF RADON 1. Inc, T.F.S. (2016) XPS interpretation of radon. Available at: http://xpssimplified.com/elements/radon.php (Accessed: 5 November 2016). 2. Habashi, F. (ed.) (1997) Handbook of extractive metallurgy. Weinheim, Toronto: Wiley-VCH Verlag GmbH. 7 Transuranium Element Features Properties Remarks Density 9.73 g/L at 1 atm Densest elemental gas and second densest gas overall Physical Properties Odorless, tasteless & invisible gas Only elemental radioactive gas Solubility High solubility in air - Melting & Boiling Point 202 K & 211.5 K - Crystal Structure FCC - Isotopes 7 With masses between 199-226 222Rn-Half-Life 3.82 days Alpha-emitter
- 8. SOURCES OF RADON 1. Habashi, F. (ed.) (1997) Handbook of extractive metallurgy. Weinheim, Toronto: Wiley-VCH Verlag GmbH. 2. Radon (2008) Available at: http://www.toxipedia.org/display/toxipedia/Radon (Accessed: 5 November 2016). 8 Rocks and soils containing high concentration of uranium, such as phosphate, granite and pitchblende are some natural sources of RADON GAS. “Some elements in this life cycle reaction also emits β and γ-particles in addition to α-particles” Last stable product is “Pb” which is also carcinogenic.
- 9. TRANSPORT MECHANISMS 1. Radon (2008) Available at: http://www.toxipedia.org/display/toxipedia/Radon (Accessed: 5 November 2016). 2. Alpha recoil (no date) Available at: http://www.toxipedia.org/display/toxipedia/alpha+recoil (Accessed: 20 November 2016). 9 After Produced Moves through small pores between soil and rocks by “Alpha Recoil” and “Mechanical Flow of air and water” Alpha Recoil??
- 10. RADON ABSORPTION AND DISTRIBUTION 1. Surgery, U.C. (no date) Bronchus / bronchi / bronchioles. Available at: http://www.cts.usc.edu/zglossary-bronchus.html (Accessed: 20 November 2016). 2. Radon (2008) Available at: http://www.toxipedia.org/display/toxipedia/Radon (Accessed: 5 November 2016). 10 Charged ions attached to aerosolized particles. After being inhaled attached to Respiratory tracts. Particularly, Bronchi origination site for most lungs cancers. “Low Solubility in body fluids Uniform Distribution”
- 11. RADON TOXICITY Radon (2008) Available at: http://www.toxipedia.org/display/toxipedia/Radon (Accessed: 5 November 2016). 11 “Health Concerns Arises because of chronic exposure above 4 pCi/L” It gives no warning, • No acute or sub-acute health effects • No irritating effects Primary Health Effect Lungs Cancer
- 12. DNA DAMAGE Radon (2008) Available at: http://www.toxipedia.org/display/toxipedia/Radon (Accessed: 5 November 2016). 12 Linear Energy Transfer (LET) Alpha particles are ionized and slow Their efficiency of energy transfer is high Genomic change is high DNA damage and Occasional cell death “The transfer of energy per unit of path length of the ionizing particle or the action of radiation per matter”
- 13. MECHANISM OF DNA DAMAGE 1. Singh, V. (2011) LET, RBE & OER. Available at: http://www.slideshare.net/vandana_rt/let-rbe-oer-dr-vandana (Accessed: 24 November 2016). 2. Urushibara, A., Shikazono, N., Watanabe, R., Fujii, K., O’Neill, P. and Yokoya, A. (2006) ‘DNA damage induced by the direct effect of he ion particles’, Radiation Protection Dosimetry, 122(1-4), pp. 163–165. doi: 10.1093/rpd/ncl425. 13 2.5 MeV α-particles 166 keV/μm “100 keV/μm is about optimal for biological effect to start taking place as the diameter of DNA’s radius matches the average ionizing events” As the LET value increases, 1. Number of SSB per dose remains more or less constant 2. Number of DSB per dose increases and reparability decreases
- 14. CELL DEATH Singh, V. (2011) LET, RBE & OER. Available at: http://www.slideshare.net/vandana_rt/let-rbe-oer-dr-vandana (Accessed: 24 November 2016). 14 RAD or GRAY (Gy) Energy absorbed per unit mass of tissue Absorbed dose Equal doses for different type of radiations are not equal because LETs are different
- 15. DETECTION METHODS SlidePlayer (2016) Presentation on theme: ‘RADON 1/ 60 © copyright training 4 today 2000 Published by Envirowin software LLC WELCOME RADON CUSTOMIZED ENVIRONMENTAL TRAINING.’— presentation transcript: Available at: http://slideplayer.com/slide/5915998/ (Accessed: 20 November 2016). 15 1. Activated Charcoal Adsorption 2. Alpha Track Detection 3. Unfiltered Track Detection 4. Charcoal Liquid Scintillation 5. Continuous Radon Monitoring 6. Electrect Ion Chamber 7. Grab Radon-Charcoal-Activated 8. Grab Radon-Pump-Collapsible-Bag 9. Grab Radon-Scintillation Cell “If we can’t quantify it then we can’t control it”
- 16. RADON DETECTION: SHORT TERM Radon group - University of Ioannina (no date) Available at: http://omega.physics.uoi.gr/radon/English/Instrumentation.htm (Accessed: 27 November 2016). 16 Alpha tracks on PADC or CR-39 “Alpha Track Detection Solid State Nuclear tracks Detectors (SSNTDs) “ Polyallyl diglycol carbonate (PADC) alpha damage tracksPADC etching microscopy C12H18O7
- 17. RADON DETECTION: LONG TERM 17Radon group - University of Ioannina (no date) Available at: http://omega.physics.uoi.gr/radon/English/Instrumentation.htm (Accessed: 27 November 2016). A schematic diagram of the chamber; Electrect Ion Chamber “Electrect Ion Chamber Continuous and long term measurements“
- 18. MITIGATION (No Date) Available at: http://www.a-and-r-radon-mitigation.com/wp-content/uploads/2014/05/reducing-radon.jpg (Accessed: 27 November 2016) 18 SealingEvaluation Installing of airborne radon reduction system
- 19. 19
- 20. Life Cycle 20
- 21. DIRECT AND INDIRECT ACTIONS 21
- 23. LET CALCULATION; BETHE EQUATION MIT-Lectures (no date) Available at: https://ocw.mit.edu/courses/nuclear-engineering/22-55j-principles-of-radiation-interactions-fall-2004/lecture-notes/energy_depos_hcp.pdf (Accessed: 5 December 2016). 23
- 24. BRAGG’S CURVE & PEAK 24
- 25. BELT OF STABILITY LibreTexts, C. (2013) Nuclear stability and magic numbers. Available at: http://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Nuclear_Chemistry/Nuclear_Stability_and_Magic_Numbers (Accessed: 5 December 2016). 25 • Above the atomic number of 83 are only unstable radioactive elements. • Stable nuclei with atomic numbers up to about 20 have an N:Z ratio of about 1:1 (solid line).
- 26. ACTION LEVEL 26WHO (no date) Radon. Available at: http://www.who.int/ionizing_radiation/env/Radon_Info_sheet.pdf (Accessed: 12 December 2016).
Editor's Notes
- #2: Shamail Ahmed
- #4: roentgen equivalent in man CGS unit of equivalent dose, effective dose, and committed dose. One rem carries with it a 0.055% chance of eventually developing cancer
- #6: Speed 6% of c 98% of c 100% of c
- #7: When N/No
- #8: Transuranium Element, p-block element. Radioactive Elements (38) These elements are radioactive. They either have no stable naturally occurring isotope, or else are entirely artificial (all artificial elements have no stable isotopes).
- #9: Radon is continually being formed in soil and released to air
- #10: Alpha recoil is defined as the process by which an atom (radon) recoils in the opposite direction from the path of particle ejection following the radioactive decay of its parent atom (#UMN).
- #11: The airways of the lungs. When a person takes in a breath of air, the air travels through the nose or mouth, into the larynx, then into the trachea, which is the main passageway into the lungs. The trachea divides into a right and left main bronchus. Each major bronchus then subdivides into smaller airway passages referred to as bronchi. As the airway passages make their way out to the lung tissue, the passages become smaller and are referred to as bronchioles. Eventually the bronchioles terminate into small collections of air sacs known as alveoli, which is where the actual exchange of CO2 and Oxygen occur.
- #13: Additionally, the alpha particle is able to transverse cell nuclei in a linear pattern and deposit energy in a fashion known as Linear Energy Transfer (LET). This refers to the energy transferred per unit of path traveled by the ionizing particle (#University of Minnesota, 2008). Since Alpha Particles travel short distances and are slow, their efficiency in transferring energy and affecting genomic change is very high, as reflected by their LET. Once deposited, this energy causes DNA alterations, cell cycle stress, and occasional cell death (#NetLibrary).
- #14: All the agents that cause cancer somehow changes the DNA and are called mutagens. In this case clustered damage.
- #17: The basis of SSNTDs is that charged particles damage the detector within nanometers along the track in such a way that the track can be etched many times faster than the undamaged material. For a given type of particle, the length of the track gives the energy of the particle. The charge can be determined from the etch rate of the track compared to that of the bulk. If the particles enter the surface at normal incidence, the pits are circular; otherwise the ellipticity and orientation of the elliptical pit mouth indicate the direction of incidence.
- #18: detector consists of an electrically charged dielectric material that produces a strong electrostatic field inside a small chamber. Radon gas is allowed to diffuse inside the chamber and the ions produced upon its decay are attracted to the electrets surface, thus causing a decrease in its charge. After proper calibration and by measuring the surface potential both before and after the exposure, the radon flux can be calculated.