“Why is it so dangerous?”

RADON GASShamail Ahmed

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PREVIEW

• Statistics and Motivation

• Radioactivity

• Chemistry of Radon

• Sources, transport mechanism and distribution of Radon

• Toxicity, DNA Damage and Cell death

• Detection and Mitigation

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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.

• Biggest cause of lungs cancer after Smoking.

• Almost everyone is exposed to some extent.

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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).

λ < 0.01 nm

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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).

Speed 6% of c 98% of c 100% of c

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IMPORTANT TERMINOLGIES AND UNITS

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

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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.

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

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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).

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.

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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).

After Produced

Moves through small pores between soil and rocks by

“Alpha Recoil” and “Mechanical Flow of air and water”

Alpha Recoil??

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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).

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”

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RADON TOXICITY

Radon (2008) Available at: http://www.toxipedia.org/display/toxipedia/Radon (Accessed: 5 November 2016).

“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

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DNA DAMAGE

Radon (2008) Available at: http://www.toxipedia.org/display/toxipedia/Radon (Accessed: 5 November 2016).

Linear Energy Transfer (LET)

Alpha particles are ionizedand slow

Their efficiency of energy transfer is high

Genomic change is high

DNA damageand Occasional cell death

“The transfer of energy per unit of path length of the ionizing particle or the action of radiation per matter”

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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.

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 constant2. Number of DSB per dose increases and reparability decreases

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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).

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

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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).

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”

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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).

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

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RADON DETECTION: LONG TERM

Radon 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“

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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)

SealingEvaluationInstalling of airborne

radon reduction system

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Life Cycle

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DIRECT AND INDIRECT ACTIONS

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SMOKING + RADON

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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).

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BRAGG’S CURVE & PEAK

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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).

• 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).

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ACTION LEVEL

WHO (no date) Radon. Available at: http://www.who.int/ionizing_radiation/env/Radon_Info_sheet.pdf (Accessed: 12 December 2016).