RADIATION AHD HEALTH HAZARDS

PROTECTION AGAINST IONIZING RADIATION

Mgr. Alexandra Filová, PhD.

alexandra.filova@fmed.uniba.sk

Effects of Radiation on People

• One sievert (Sv) is a large dose

• 10 Sv - Risk of death within days or weeks

• 1 Sv - Risk of cancer later in life

• 100 mSV - Risk of cancer later in life

• 50 mSv - Threshold limit values (TLV) for annual dose

for radiation workers in any one year

HALF LIFE T½ = Time of decreasing the activity of

radionuclide into half

14C = T½ = 5730 years 90Sr = T½ = 28.8 years 131I = T½ = 8.4 days 217Rn = T½ = 10-3 sec. 222Rn = T½ = 3.8 days

LCSR - accidental release of IR, irradiation of persons or release into

the atmosphere

Radiation accident Radiation disorder

(incident)

Loss of control under sources of ionizing

radiation

LCSR

Radiation disorder (incident)

LCSR, unplanned irradiation of citizens, breaking the

rules of radiation protection, on the level under the

radiation limits

Radiation accident

LCSR, irradiation of citizens on the workplace with

sources of IR on the limit level or higher, results in

exceeding the limits and workers` irradiation

LCSR, results in the release of radioactive substances or

ionizing radiation into the environment and countermeasures

for public protection are needed

Radiation breakdown

(major, serious accident)

Nuclear breakdown

(major, serious accident)

Loss of control under nuclear reactor, results in release of

radioactive substances or ionizing radiation into the

environment and countermeasures for public protection are

needed

INES The international nuclear and radiological event scale

Zz. 35/2012

The Situation at Fukushima (11 March 2011)

• earthquake of magnitude 9 hit the

nuclear power plant Fukushima I and II.

on the east coast of Japan, Okuma

• 3rd highest magnitude in the world

Chile 1960: 9.5;

Sumatra 2004: 9,2

• Tsunami height:

15 m Fukushima

21 m Tomioka

43 m Onagawa

The Situation at Fukushima (11 March 2011)

- a major earthquake on caused a 15-metre tsunami to strike the

Fukushima Daiichi nuclear power plant on Japan's Tohoku coast,

disabling the power supply and heat sinks, thereby triggered a

nuclear accident.

Without cooling water, the cores of units 1, 2 and 3 overheated and

largely melted in the first three days. Hydrogen generated by this

high-temperature process caused explosions in the upper service

floors of reactor buildings at units 1 and 3. Unit 4 had not been

operating, but was affected by a hydrogen explosion. All four reactors

were written off. Two other reactors at the plant were not involved in

the accident.

The Situation at Fukushima (11 March 2011)

- the major accident was rated at Level 7 on the International Nuclear

Event Scale due to high radioactive releases to air in the first few

days.

-The bulk of releases occurred with the explosions, while a leak of

contaminated water to sea continued for two months.

-Further releases of radioactivity to the air were brought to

insignificant levels before the end of 2011, although much

radioactivity remains dispersed on the ground in the surrounding area

Effects on people

- significant amount of radioactivity was released, but

prompt evacuation from the immediate area made sure

that no member of the public received enough exposure

to cause harm

- about 160,000 people were evacuated from their homes

and only in 2012 were some allowed limited return

Chernobyl (26. 4. 1986) – a reactor exploded at the

Chernobyl nuclear power station, resulting in extensive global

contamination through the release of radioactive gases

More than 116, 000 people were evacuated and 31 died (1

immediately and 30 from acute radiation sickness) – 28 firemen

Activity release to the atmosphere was dispersed around the globe,

caesium - 137 – 7x1016 Bq was released, iodine-131 was the second

most important element. Radionuclides were found in many foods

over a period of months in many countries

First signals about escape of radionuclides abroad detected by

Sweden 27.4.1986. Strike of personnel of monitoring stations in

Finland.

Chernobyl nuclear reactor was determined by American satellite

receivers.

There was a mild south-east wind and radioactive substances

circulated - higher - west part of USSR- to Finland and to Sweden.

30. April the direction of wind changed and the air circulated from

north-east to Czechoslovakia.

Watch video about radioactive cloud: https://www.youtube.com/watch?v=5jMDMgOAWhI&feature=youtu.be

Slovakia:

First signals about contaminated air were detected from northeast- in

the night from 29. - 30. April at control measurements in nuclear power

plants, then weaker flow of contaminated air from 3.- 5. May

Institute of Hygiene and Epidemiology in Prague

Research Institute of Hygiene in Bratislava

Nuclear Power Plant Research Institute (VUJE)

Slovak Hydrometeorological Institute – SHMI

30. April - 8. May - daily meetings of Governmental commission for

outbreaks.

In our region - 30. 4. and 1. 5. 1986 volume activity of 131I in the

air was the highest

(30% iodine in the form of aerosol, 35 % elementary in the gaseous

form and 35 % organ binded), the content of radionuclides in milk and

dairy products was controlled in 25 selected dairies.

Activity of 131I in milk in dairies after 15.5.1986 did not exceed the action limit level Bq/l.

• Milk with higher content of 131I - sheep milk.

• Shepherds and herdsman received potassium iodine to protect thyroid.

• It was recommended to consume the supplies of desiccated and condensed milk.

Simple

impairment

30 - 40 %

Combined

impairment

(65 - 70 %)

The distribution of damage from nuclear explosion

radiation 15 - 20%

burns 15 - 20 %

injuries < 5%

burns +

radiation 40%

burns+

injuries+

radiation 20%

injuries+

radiation 5 %

injuries +

burns 5 %

Areas of endanger

In the areas near nuclear power stations in Slovak republic - in the

shape of a circle with diameter

25 km in the area

Jaslovské Bohunice

20 km in the area

Mochovce.

Citizen warning

Warning signals :

• general endanger – two minutes rolling tone

of sirens as at endanger or at emergency

situation

End of endanger – a two-minute standing-tone of sirens without repetition, supplemented by spoken

information through mass media

Zz. 47 / 2012

Plan of health protection of citizens from accidental release

of radioactive substances

According to special requirements and emergency plan

the phase of endanger,

the early phase,

the intermediate phase,

the recovery phase.

Some advices in case of radioactive accident

(What to do, when something happens)

1. Take shelter in basements, dwellings, buildings. Make all crevices and

cracks tight (turn off ventilation and air conditioning equipment).

2. Take the iodine preparations (tablets of KI). Keep the dosage.

3. Turn off the gas.

4. Do not disconnect the electricity (think about the food in refrigerators and

freezers).

5. Common foodstuff put into cupboards, boxes (protect from radioactive

contamination).

6. Make supply of drinking water in bottles and vessels. Make them safe

against radioactive contamination.

7. Do not let pets outside. Those having been outdoors do not let into the flat or

house. Farming animals close in stables and sheds providing them with food and

water for several days.

8. Do not go outside without a reason. If you are forced to leave the shelter

protect respiratory ways (handkerchief or towel) and protect body surface with

plastic.

9. Prepare all necessary things (documents, medicaments, incl. iodine tablets,

food, drinking water, jewelry) for evacuation.

10. Respect mayor, police and other organs

11. Children in schools and kindergartens are evacuated by them.

12. Follow news in the media.

12. Do not use telephone unnecessarily.

13. Be kind and respect all other citizens.

Good interpersonal relations help to solve critical situation

WHEN AND HOW TO USE POTASSIUM IODINE

After announcement of radiation or nuclear breakdown and on appeal citizens use

potassium iodine tablets in dosages:

- Newborns until 1 month 1/4 tbl. = 16 mg

- Suckling and children till 3 years 1/2 tbl. = 32 mg

- Children 3 -12 years 1 tbl. = 65 mg

- Children over 12 years and adults 2 tbl. = 130 mg

Usage of higher dosages doesn`t increase the protective effect!

The exception are persons susceptible to iodine remedies and treated for thyroid disorders

Residents in protected zones should pick up iodine preparation in

urban or municipal offices.

At the work-place the employer provides the iodine preparations.

Potassium iodide blocks radioactive iodine (I-131) from absorption

by thyroid

Radioactive waste disposal

Since the year 2000, the use of superficial National Radioactive

Waste Disposal, which is about 2 km northwest of the nuclear

power plant Mochovce.

it consists of 80 boxes, to each 90 fiber-concrete containers could be placed

the capacity is sufficient to 7200 containers, there would be, however, 35

thousand needed

at the end of the year 2009, in the national repository was 2,175 containers,

their average weight was 8,606 kg

Dose equivalent HT /equivalent dose

Different biological effects of different types of radiation.

It is the averaged absorbed dose in tissue or organ

multiplied by a radiation weighting factor - quality factor

(in the table)

Radiation weighting factor wR:

- is a dimensionless coefficient used for weighting the dose absorbed by tissue, or organ - expresses a different biological effect of different type of ionizing radiation

!!! Note: in 2018 a new Act no. 87/2018 Coll. on radiation protection =

currently valid limits and weighting factors are in the presentation.

Type of radiation Radiation weighting factor, quality factor

WR

Photons 1

Electrons, muons (all energies) 1

Protons and charged pions 2

Alpha particles,

fission fragments, heavy ions 20

RADIATION WEIGHTING FACTORS

Effective dose E

is the sum of exposures received by a tissue obtained by

multiplying the dose equivalent HT by a tissue specific weighting

factor for each radiation type or source.

(WT _in the table).

Tissue specific weighting factor wT

is a dimensionless coefficient used for weighting the equivalent dose in tissue or organ

TISSUE SPECIFIC WEIGHTING FACTORS

Tissue, organ Tissue specific weighting factor WT

Red bone marrow 0.12

Lungs 0.12

Colon 0.12

Stomach 0.12

Breast 0.12

Remainder tissues 0.12

Gonads 0.08

Esophagus 0.04

Urinary bladder 0.04

Liver 0.04

Thyroid 0.04

Bone surface 0.01

Salivary glands 0.01

Brain 0.01

Wholebody total 1.00

………. ………….. …………. ……….

……………………………….…….. ………... ……. …..

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .

…... …... …… …. .…...… ……... ……… ……… ……… ……. ……. ……. ……. ……. …...

gonads

0.05 Sv

lungs

0.1 Sv

0.08 . 0.05

0.004 Sv

0.012 Sv

0.12 . 0.1

0.016

T

T

T HW

Tissue specific weighting factor

Adverse health effects of radiation

1. Deterministic (non-stochastic, treshold) effects - result in large part

to the killing/multifunction of cells following high doses

- are related directly to the absorbed radiation dose and the severity of

the effect increases as the dose increases.

A deterministic effect typically has a threshold (of the order of magnitude

of 0.1 Gy or higher) below which the effect does not occur.

Deterministic effects are based on tissue damage.

2. Stochastic effects, mutation or malignant transformation

of 1 or more cells

- are chance events, with the probability of the effect increasing with

dose, but the severity of the effect is independent of the dose

received.

- Stochastic effects are assumed to have no threshold.

- Primarily cancer risk.

IMMEDIATE AND LATE EFFECTS OF RADIATION

EXPOSURE

Immediate effects Late effects

Somatic Genetic

NON STOCHASTIC STOCHASTIC

Fetal impairment

cancer genetic

effects

acute

radiation

syndrome

acute local

impairment

late

impairments

other than

cancer

PRINCIPLES OF RADIOLOGICAL PROTECTION

• JUSTIFICATION (no practice shall be adopted unless its

induction produces a positive net benefit)

• OPTIMIZATION (all exposures shall be kept as low as

reasonably achievable, with economic and social factors

being taken into account)

• LIMITATION (the dose equivalent to individuals shall not

exceed the limits recommended for the appropriate

circumstances by the Commission)

Protection standards

Primary limits - Dose limits for workers and public

Secondary limits

Derived limits

Reference levels registration (evidence) 1/10 NPD, examination (examine) 3/10 NPD

•intervention (start action)

Organs and tissues Worker (mSv/year)

Public and pupils

under 16 years of

age (mSv/year)

Students aged 16 to

18 years

Whole body irrad.

(effective dose) 20 mSv 1 mSv 6 mSv

Eye lens (equivalent

dose) 20 mSv 15 mSv 15 mSv

Skin - aver. cm2

(equivalent dose) 500 mSv 50 mSv 150 mSv

Hands - forearm

Legs - ankle

(equivalent dose)

500 mSv - 150 mSv

Special irradiation (life-saving activities) not more than effective dose 250 mSv

DOSE LIMITS FOR WORKERS

AND PUBLIC

In the occupational environment the exposure of workers is controlled by

personal dosimeters

Measurement of personal doses - Department of Personal Dosimetry - metrological

workplace in Bratislava,

- TLD (termoluminiscence dosimeters)

- OSL dosimeters (optically stimulated luminiscence) in

Žilina

Film dosimetry (FD)

Historic method - shows a relatively accurate results, but at the cost of a complicated and

challenging process of evaluation. This process is difficult to automate and thus exclude the

possibility of errors in the evaluation due to the human factor. In the world the film dosimetry

has been waived for several years and in the future the further development is unlikely.

Termoluminiscence (TLD)

Method, which began to replace film dosimetry as the first and still has been used in many countries for personal

dosimetry. Its advantage over film dosimetry is the possibility of automatic evaluation of dosimeters and also lower

sensitivity to external influences, the disadvantage remains a complicated method of assessment.

In some areas (such as finger dosimetry) has still the irreplaceable role.

Optically stimulated luminiscence (OSL)

The method that in the course of the last ten years has replaced by FD and TLD worldwide, and its advantages

(highly resistant dosimeter, quick and easy evaluation) designate it to be the integral personal dosimetry for the

future.

Neutron dosimetry (ND)

To measure the external neutron irradiation Neutrak trace detectors have been used, which are placed in the

standard tray used in the whole-body OSL dosimeter.

Measurement takes place during a defined period and then is evaluated in the form of burns and counting the

holes.

Termoluminiscence dosimeter (TLD)

Every TL dosimeter is a special and unique integral detector, integrating “information on

dose” permanently, without possibility to be “switched off” when the person is not exposed

to the source of ionizing radiation, because during this time the dosimeter records the

doses of ionizing radiation from the natural environment.

The life of TL dosimeter is more than 500 evaluation cycles, i.e. cca 80 years provided, it

is handled with care

The TL dosimeter consists of several parts:

• Holder of dosimeter. The holder is specially adjusted so that it simulates various

layers of human tissue on the principle of different filtration, and enables in this

manner to determine the personal dose equivalent in various depths of the tissue.

• Dosimetry card or chip (so called doseclip). The chip contains the

thermoluminescence material sensitive to ionizing radiation that is closed in

vacuum between two transparent teflon foils.

OSL dosimeter

The principle of OSL dosimeters is similar to the principle in TLD

dosimeters, the difference is in the way of the crystal stimulation.

In TLD dosimeters it is heating and in OSL dosimeters it is LED light.

Stimulation of irradiated OSL material (crystal Al2O3: C) with the green

light from the LED diode has resulted in the emitting

of a blue light, the intensity of which is proportional

to the radiation dose.

Finger dosimeter and wrist dosimeter

Radioactivity in the environment

Radon risk

Sours of natural radiation

Cosmic radiation

consist of galactic cosmic rays

the dose doubles approximately

every 1,500 m altitude

Radiation from soil

case by 40K (potassium40 is one of the most widespread radionuclides in countryside)

Radiation from water

dissolving of minerals and rocks

in sea waters the content of radionuclides is higher than in inland waters

Radiation from atmosphere – caused mainly by 222Rn and its daughters

Natural and artificial ionizing radiation

Radon 42 %

Gamma terrestrial radiation

and construction materials

15 %

Other

1 %

Medical

performances

20 %

Consumer products 8 %

Cosmic radiation

13 %

Other (1 %) - occupational 0.3 %, nuclear fallout 0,3 %

Average radiation exposure from all sources (annual effective dose =3.0 mSv)

Source: UNSCEAR, 2008, Report to the General Assembly

0.60 mSv/year

Medical exposure 0.60 mSv

Occupational exposure 0.005 mSv

Nuclear testing 0.005 mSv

Nuclear industry less than 0.0002 mSv

Chernobyl less than 0.002 mSv

Worldwide annual exposure from artificial sources

Worldwide annual exposure from natural sources

2.4 mSv/year

Radon 1.26 mSv

Terrestrial 0.48 mSv

Ingestion 0.29 mSv

Cosmic radiation 0.39 mSv

RADON

• natural inert radioactive gas

• odorless, colorless, chemically non-reactiv gas

• is produced by decay of uranium - radium - radon

• one of the major natural sources of radioactive isotopes on earth

Radon has three radioisotopes

actinon (219Rn)

thoron (220Rn)

radon (222Rn)

Radon 222Rn half life 3.82 days

Decay daughters

218Po 214Pb

214Bi 214Po

210Pb

Meteorologic and geologic factors modifying radon concentrations

Radon concentration

in soil

Air

pressure

Temperature

Humidity

Downfall

Speed and wind

direction

Radon in soil

Soil properties

Tectonic disorders

(earthquake, volcano)

Level of underwater

Meteorology Geology

Radon daughters

corpuscular characteristics

(characteristics of metal atoms)

Particles

in the air easily interact with liquid and solid particles

Create

Radioactive aerosol with particles of size from 1 – 10 μm.

They are breaking and radiate and radiation

The decay ends as non active lead.

Important and strong radiotoxic alfa emitters.

The risk of lung cancer is proportional to dose, that lung epithel cells get

after irradiation from radon.

Radon was classified as A group carcinogen.

The synergic effect of radon and smoking exposure.

Radon and daughters are everywhere.

The highest activities are especially in closed spaces, indoor air.

houses

mines

caves

The most important population exposure is from indoor

air in closed ground objects

Houses

Industrial objects

Administrative houses

Social institutions

Chimney effect

• Work especially during the whole heating season

• efficiency is determined by the size of the difference in internal and external temperatures

Radon penetrates buildings from the subsoil:

• diffusion

• flow through non-insulated – floor

– cracks

– holes in foundations and floor

– sewerage

The radon concentration in the indoor atmosphere is also influenced by

meteorological conditions (temperature, humidity, barometric pressure,

wind speed) and seasons.

Therefore, maximum concentrations are achieved in winter months and at

least in summer (differences are 2-5 times).

Measurement of volumetric radon activity in soil air

A – sampling tube D – suction head F - Lucas G – device for measuring volumetric

B – cut-stick E – syringe scintilation activity of radon

C – lost tip (JANETT) chamber H – control panel of the apparatus

I – probe device

J – circular transducer scintilation

chambers

Procedure for determining the volumetric activity of radon in soil air

permeability of the subsoils in the building lot

- volumetric activity of radon in soil gas provides a set of measurements of at least 15 samples taken from different locations of the depth of 0.8 m

- in the assessment area greater than 800 m2 sampling carried out in the network 10 x 10 m at a future built-up area and the nearest place

in the case of higher volumetric radon actiivity – in the network 5 x 5 m

Radon enters the home from the soil beneath the foundation,

well water used for domestic supply can also be the source

Building materials – brick, concrete do produce radon

The main source of high indoor levels is the ground

ground building materials

soil

Indoor radon concentrations in OECD countries Worldwide average 39

Indoor Radon Levels (Bq/m3)

Country OECD Arithmetic mean Geometric mean Geometric standard deviation

Australia 11 8 2.1

Austria 99 15 NA

Belgium 48 38 2.0

Canada 28 11 3.9

Czech Republic 140 44 2.1

Denmark 59 39 2.2

Finland 120 84 2.1

France 89 53 2.0

Germany 49 37 2.0

Greece 55 44 2.4

Hungary 82 62 2.1

Iceland 10 NA NA

Ireland 89 57 2.4

Italy 70 52 2.1

Japan 16 13 1.8

Luxembourg 110 70 2.0

Mexico 140 90 NA

Netherlands 23 18 1.6

New Zealand 22 20 NA

Norway 89 40 NA

Poland 49 31 2.3

Portugal 62 45 2.2

Republic of Korea 53 43 1.8

Slovakia 87 41 2.2

Darby S et al. Radon in homes and risk of lung

cancer: collaborative analysis of individual data

from 13 European case-control studies. BMJ.

2005

Lung cancer risk, radon, smoking

0

20

40

60

80

100

120

140

750 370 300 150 75 50 15

Wholelife exposure to

radon in 1000 smokers

Wholelife exposure to

radon in 1000

nonsmokers

Number of lung

cancer cases

Radon concentration in Bq/m3

8 4 3 2 1

1 1

RAMON - RADON MONITOR 2.2

Electronic radon detector, long-term monitoring, short-term measurements,

reliably monitors indoor spaces for radon gas

The average annual effective dose of citizens from radon and daughters

inhalation in houses according to districts in SR

Problems of radon occupational exposure and household exposure

- important

complex national radon programmes

to lower the exposure

The average activity of radon is different in different countries

10 - 100 Bq.m-3 (average 40 Bq.m-3).

From the measurements in 54 Slovak towns – the number of reference

surfaces classified into the

low, medium and high radon risk is the ratio

51 : 46 : 3 %

The relatively highest percentages of surfaces classified into medium and high

radon risk are in the urban areas

Bánovce nad Bebravou, Bytča, Pezinok, Poprad, Púchov, Šaľa, Topoľčany, Zlaté Moravce a Žilina.

The most favorable situation was measured in

Holíč, Skalica, Vranov nad Topľou,

where 100% of the reference areas were in the category of low radon risk

Derived intervention level to reduce the content of natural radionuclides

in construction products is mass activity of 226Ra

120 Bq.kg-1

- 370 Bq.kg-1 in construction material for building indoor houses

- 3700 Bq. Kg-1 in construction material to build houses for certain stay

longer than 1000 hours during calendar year

Monitoring in construction materials

The maximum allowable equivalent of 226Ra activity is:

PROTECTION AND PREVENTION

The best approach is to prevent entering from ground by drawing radon laden

air from under the floor and discharge it to the atmosphere. A small sump, duct,

fan should be installed, gaps in floor should be closed for best results.

Underground ventilation and antiradon detailing.

Measurement is always required to determine whether a particular home is

adversely affected by radon.

ICRP guidelines – 200 Bq.m-3 for new housing

400 Bq.m-3 at 50 percent equilibrium for existing houses

WHO proposes a reference level of 100 Bq/m3 to minimize health hazards due

to indoor radon exposure. However, if this level cannot be reached under the

prevailing country-specific conditions, the chosen reference level should not

exceed 300 Bq/m3 which represents approximately 10 mSv per year according

to recent calculations by the ICRP

https://www.youtube.com/watch?v=3QXSkXHDZgU

Radioactive Waste - The Journey to Disposal