Datensammlung zur Strahlenbelastung
Units
|
SI-Unit |
Old Unit - Comment |
| Activity |
Bequerel (Bq) |
Curie (1 Ci = 3.7 1010Bq) |
| Radiation Dose |
Roentgen (R) |
1 R is the amount of gamma or x-rays
required to produce ions resulting in a charge of 0.000258
coulombs/kilogram of air under standard conditions.
1 R is the amount of radiation that
produces 1 coulomb
of ions in 1 cm3 of dry air at zero degrees celsius at standard
atmospheric pressure.
1 R of gamma radiation exposure
results in about 1 rad of
absorbed dose. |
| Absorbed Dose |
Gray (Gy) = 1 Joule/kg |
1 rad = 0.01 Gy |
| Equivalent Dose |
Sievert (Sv) = Gy x Q
(Q = quality factor, dose factor) |
1 rem = 0.01 Sv (100 mrem/mSv
oder 1 mrem/(10 µSv))
(1 mrem = 10 µSv)
roentgen equivalen
man
For gamma rays and beta particles,
1 rad of exposure results in 1 rem of dose (Q = 1).
Radionuclides
Notice of Data Availability Technical Support Document, USEPA, March
2000 (local
link)
Dose equivalent means the
product of the absorbed dose from ionizing radiation and such factors (among
them Q) which account
-
for differences in biological effectiveness
due to the type of radiation and
-
its distribution in the body as specified
by the International Commission on Radiological Units and Measurements
(ICRU) (40 CFR 141.2).
|
| Dosisfaktor |
Sv/(Bq incorporated)
dose equivalent (Sv) = dose factor
x Bq incorporated
activity (Bq) deposited in an organ
depends on intake pathway. Sv in an organ is a function of Bq deposited
in that organ. Dose factor depends on intake pathway, because Bq deposited
varies with intake pathway. |
Radionuclides
Notice of Data Availability Technical Support Document, USEPA, March
2000
Effective dose equivalent
(EDE) means the sum of the products of
-
the dose equivalents in individual organs
and
-
the organ weighting factor (USEPA, 1991).
Sum of all organ weighting factors = 1.
....
EPA knew that partial body irradiation
was common for ingested radionuclides since they are, like radium, largely
deposited in a particular organ.
In such cases, EPA acknowledged
that the risk per millirem varies depending on the radiosensitivity of
the organs at risk.
For example (thyroid exposure compared
with whole body exposure):
EPA estimated that cancers due to
the thyroid gland receiving 4 mrem per year continuously ranged
from about 0.2 to 0.5 per year per million exposed persons (averaged
over all age groups).
Fatality due to thyroid cancer varies
with age, from nearly zero for children and young adults to about 20 percent
of the incidence for persons well past middle age.
EPA noted (therefore) that estimated
fatalities from thyroid exposure were at least five times less than that
from whole body exposure. |
Q = 1, for beta particles
and all electromagnetic radiation (gamma rays and x-rays);
Q = 10, for neutrons from spontaneous
fission and protons; and
Q = 20, for alpha particles and
fission fragments.
Primordial radionuclides are left over
from when the world and the universe was created. They are typically long
lived, with half-lives often on the order of hundreds of millions of years.
Radionuclides that exist for more than 30 half-lives are not measurable.
The progeny or decay products of the long lived radionuclides are also
in this heading. Here is some basic information on some common primordial
radionuclides:
Primordial nuclides
| Nuclide |
Symbol |
Half-life |
Natural Activity |
| Uranium 235 |
235U |
7.04 x 108
yr |
0.72% of all natural uranium |
| Uranium 238 |
238U |
4.47 x 109
yr |
99.2745% of all natural uranium;
0.5 to 4.7 ppm total uranium in the common rock types |
| Thorium 232 |
232Th |
1.41 x 1010
yr |
1.6 to 20 ppm in the common rock
types with a crustal average of 10.7 ppm |
| Radium 226 |
226Ra |
1.60 x 103
yr |
0.42 pCi/g (16 Bq/kg) in limestone
and 1.3 pCi/g (48 Bq/kg) in igneous rock |
| Radon 222 |
222Rn |
3.82 days |
Noble Gas; annual average air concentrations
range in the US from 0.016 pCi/L (0.6 Bq/m3) to 0.75 pCi/L (28
Bq/m3) |
| Potassium 40 |
40K |
1.28 x 109
yr |
soil - 1-30 pCi/g (0.037-1.1 Bq/g) |
Some nuclides like 232Th
have several members of its decay chain. You can roughly follow the chain
starting with 232Th
232Th --> 228Ra
--> 228Ac --> 228Th --> 224Ra -->
220Rn
--> 216Po -->
212Pb --> 212Bi --> 212Po
--> 208Pb (stable)
Some other primordial radionuclides
are 50V,
87Rb,
113Cd,
115In,
123Te,
138La,
142Ce,
144Nd,
147Sm,
152Gd,
174Hf,
176Lu,
187Re,
190Pt,
192Pt,
209Bi.
Nuclear Data
United
States Geological Survey Digital maps of estimated potassium, equivalent
uranium-238, equivalent thorium-232 concentrations for the conterminous
U.S.
Russ
Brown:
Potassium-40 content of the body
can be obtained from its natural abundance of 0.0117% of potassium and
calculating the specific activity of natural potassium (30.5 Bg/g) using
the half life (1.28 x 109 y). The potassium content of the body is 0.2%,
so for a 70 kg man the amount of 40-K
will
be about 4.26 kBq.
14C content of the body is based
on the fact that one 14C atom exists in nature for every 1,000,000,000,000
12C atoms in living material. Using a half life of 5730 y, one obtains
a specific activity of 0.19Bq/g of carbon. As carbon is 23 percent of the
body weight, the body content of 14-C for a 70 kg man would be about
3.08
kBq.
(Rn-222 decay
scheme)
(Actinium
Series)
Bundesinstitut für
Strahlenschutz: Radon
in Bodenluft
Tab. 22.2: Radonkonzentrationen
in Wohnhäusern der Bundesländer
(Stand der Messungen: 1999)
| Bundesland |
Anzahl Wohngebäude in Tausend |
Medianwert in Bq/m3 |
geschätzter Anteil in %
mit einer Belastung
>200 Bq/m3 |
geschätzter Anteil in %
mit einer Belastung
>400 Bq/m3 |
| Baden-Württemberg |
1 831,8 a) |
38 |
2,9 |
0,6 |
| Bayern |
2 218,8 a) |
41 |
3,3 |
1,2 |
| Berlin |
265,8 a)b) |
27 |
0,3 |
0 |
| Brandenburg |
472,6 b) |
26 |
0 |
0 |
| Bremen |
121,1 a) |
30 |
0 |
0 |
| Hamburg |
207,2 a) |
27 |
0,2 |
0 |
| Hessen |
1 102,8 a) |
40 |
1 |
0,2 |
| Mecklenburg-Vorpommern |
294,6 b) |
39 |
> 0 1) |
> 0 1) |
| Niedersachsen |
1 577,1 a) |
32 |
0,8 |
0,1 |
| Nordrhein-Westfalen |
2 976,9 a) |
35 |
0,6 |
0,2 |
| Rheinland-Pfalz |
884,1 a) |
51 |
2,3 |
0,4 |
| Saarland |
261,5 a) |
46 |
1,8 |
0,4 |
| Sachsen |
692,9 b) |
47 |
6,5 |
2 |
| Sachsen-Anhalt |
502,6 b) |
34 |
0,8 |
> 0 1) |
| Schleswig-Holstein |
576,5 a) |
36 |
1,1 |
> 0 1) |
| Thüringen |
462,1 b) |
54 |
3,9 |
0,7 |
a) Gebäude- und Wohnungszählung
vom 25. Mai 1987
b) Gebäude- und Wohnungszählung
1995
1)aufgrund der Erfahrungen
über die regionale Verteilung des Radonpotentials im Untergrund ggf.
tatsächlicher Prozentsatz höher als die über den aus Stichproben
ermittelten Ergebnisse.
Quelle:
Bundesamt
für Strahlenschutz [22-6]
EPA Radon
Risk Comparison Charts
| RADON RISK IF YOU SMOKE |
| Radon Level |
If 1,000 people who smoked
were exposed to this level over a lifetime... |
The risk of cancer from
radon exposure compares to... |
WHAT TO DO:
Stop smoking and... |
| 20 pCi/L |
About 135 people could get lung cancer |
100 times the risk of drowning |
Fix your home |
| 10 pCi/L |
About 71 people could get lung cancer |
100 times the risk of dying in a home fire |
Fix your home |
| 8 pCi/L |
About 57 people could get lung cancer |
|
Fix your home |
| 4 pCi/L |
About 29 people could get lung cancer |
100 times the risk of dying in an airplane crash |
Fix your home |
| 2 pCi/L |
About 15 people could get lung cancer |
2 times the risk of dying in a car crash |
Consider fixing between 2 and 4 pCi/L |
1.3 pCi/L
= 48 Bq/m3 |
About 9 people could get lung cancer |
(Average indoor radon level) |
(Reducing radon levels below 2 pCi/L is difficult.) |
0.4 pCi/L
= 15 Bq/m3 |
About 3 people could get lung cancer |
(Average outdoor radon level) |
(Reducing radon levels below 2 pCi/L is difficult.) |
| Note: If you are a former smoker, your risk may
be lower. |
| RADON RISK IF YOU HAVE NEVER SMOKED |
| Radon Level |
If 1,000 people who never
smoked were exposed to this level over a lifetime... |
The risk of cancer from
radon exposure compares to... |
WHAT TO DO: |
| 20 pCi/L |
About 8 people could get lung cancer |
The risk of being killed in a violent crime |
Fix your home |
| 10 pCi/L |
About 4 people could get lung cancer |
|
Fix your home |
| 8 pCi/L |
About 3 people could get lung cancer |
10 times the risk of dying in an airplane crash |
Fix your home |
| 4 pCi/L |
About 2 people could get lung cancer |
The risk of drowning |
Fix your home |
| 2 pCi/L |
About 1 person could get lung cancer |
The risk of dying in a home fire |
Consider fixing between 2 and 4 pCi/L |
1.3 pCi/L
= 48 Bq/m3 |
Less than 1 person could get lung cancer |
(Average indoor radon level) |
(Reducing radon levels below 2 pCi/L is difficult.) |
0.4 pCi/L
= 15 Bq/m3 |
Less than 1 person could get lung cancer |
(Average outdoor radon level) |
(Reducing radon levels below 2 pCi/L is difficult.) |
| Note: If you are a former smoker, your risk may be
higher. |
Radon
Frequently Asked Questions
Cosmic radiation permeates all of space,
the source being primarily outside of our solar system. The radiation is
in many forms, from high speed heavy particles to high energy photons and
muons. The upper atmosphere interacts with many of the cosmic radiations,
and produces radioactive nuclides. They can have long half-lives, but the
majority have shorter half-lives than the primordial nuclides. Here is
an table with some common cosmogenic nuclides:
Cosmogenic Nuclides
| Nuclide |
Symbol |
Half-life |
Source |
Natural Activity |
| Carbon 14 |
14C |
5730 yr |
Cosmic-ray interactions, 14N(n,p)14C; |
6 pCi/g (0.22 Bq/g) in organic material |
| Tritium 3 |
3H |
12.3 yr |
Cosmic-ray interactions with N and
O; spallation from cosmic-rays,
6Li(n,alpha)3H |
0.032 pCi/kg (1.2 x 10-3
Bq/kg) |
| Beryllium 7 |
7Be |
53.28 days |
Cosmic-ray interactions with N and
O; |
0.27 pCi/kg (0.01 Bq/kg) |
Some other cosmogenic radionuclides
are 10Be,
26Al,
36Cl,
80Kr,
14C,
32Si,
39Ar,
22Na,
35S,
37Ar,
33P,
32P,
38Mg,
24Na,
38S,
31Si,
18F,
39Cl,
38Cl,
34mCl.
You are made up of chemicals, and it
should be of no surprise that some of them are radionuclides, many of which
you ingest daily in your water and food. Here are the estimated concentrations
of radionuclides calculated for a 70,000 gram adult based ICRP 30 data:
Natural Radioactivity in Your Body
|
Nuclide
|
Total Mass of Nuclide
Found in the Body
|
Total Activity of Nuclide
Found in the Body
|
Daily Intake of Nuclides
|
|
Uranium
|
90 µg
|
30 pCi (1.1 Bq)
|
1.9 µg
|
|
Thorium
|
30 µg
|
3 pCi (0.11 Bq)
|
3 µg
|
|
Potassium 40
|
17 mg
|
120 nCi (4.4 kBq)
|
0.39 mg
|
|
Radium
|
31 pg
|
30 pCi (1.1 Bq)
|
2.3 pg
|
|
Carbon 14
|
95 µg
|
0.4 µCi (15 kBq)
|
1.8 µg
|
|
Tritium
|
0.06 pg
|
0.6 nCi (23 Bq)
|
0.003 pg
|
|
Polonium
|
0.2 pg
|
1 nCi (37 Bq)
|
~0.6 µg
|
The average annual dose equivalent from
the internal deposited radionuclides is given in the entry Internal
in table Radiation Doses
to the US Pop.
Population Dose
Average
Annual Population Dose:
-
3.6 mSv/a (360 mrem/a), of this dose
-
0.2 mSv/a (20 mrem/a) being due to K-40.
Cosmic
Radiation:
-
From cosmic radiation (high energy g-rays,
Q
= 1) in the U.S. the average person will receive a dose of 27 mrem per
year and this roughly doubles
every 6,000 foot increase in elevation.
-
in the Northeastern US: 4
µR/hr = 35 mR/a
-
at 15,000 feet: 20
µR/hr = 175 mR/a
-
at 55,000 feet: 300
µR/hr = 2630 mR/a
-
at sea level: 26 mrem/a
-
in Denver (2000 m): 50 mrem/a
Effektive Dosis durch ionisierende Strahlung
im Jahr 1999:
Mittlere Effektive Dosis ca. 4,5 mSv
Quelle: Bundesamt für Strahlenschutz;
eigene
Zusammenstellung, Januar 2001
|
Strahlungsart
|
Gesamtbevölkerung
|
Berufliche
Strahlenexposition
gemittelt über
ca. 334 000 Personen
|
| Natürliche Strahlenquellen |
|
|
| Kosmische Strahlung |
0,3 mSv |
|
| Nahrung |
0,3 mSv |
|
| Inhalation von Radon und seinen
Zerfallsprodukten |
1,4 mSv |
|
| Terrestrische Strahlung |
0,4 mSv |
|
|
|
|
| Künstliche Strahlenquellen |
|
|
| Reaktorunfall Tschernobyl |
0.02 mSv |
|
| Atombomben-Fallout |
0.01 mSv |
|
| Forschung,Technik,Haushalt |
0,01 mSv |
|
| Kerntechnische Anlagen |
0,01 mSv |
0.17 mSv |
| Medizin |
2.00 mSv |
|
Tab. III.4 S. 25 aus: Umweltradioaktivität
und Strahlenbelastung im Jahr 2001,
Bundestagsdrucksache 14/9995,
Zugeleitet mit Schreiben des Bundesministeriums
für Umwelt, Naturschutz und Reaktorsicherheit vom 30. September 2002,
Bundesamt für Strahlenschutz
Princeton
Univeristy:
Radiation
Doses to the U.S. Population (NCRP
93)
| Radiation source |
Average annual whole body
dose (millirem/year)
|
Natural: Cosmic
(cosmic + terrestrial + radon
in Pittsburgh = 10 mR/a) |
29 |
|
Terrestrial |
29 |
|
Radon |
200 |
| Internal
(K-40, C-14, etc.) |
40 |
| Manmade: Diagnostic
x-ray |
39 |
|
Nuclear Medicine |
14 |
|
Consumer Products |
11 |
All others (fallout, air
travel, occupational, etc.) |
2 |
|
Average annual total |
360 millirem/year
|
Average doses from some common
activities
| Activity |
Typical Dose |
| Smoking |
280 millirem/year |
Using radioactive materials
in a Princeton University
lab |
<10 millirem/year |
| Dental x-ray |
10 millirem per x-ray |
| Chest x-ray |
8 millirem per x-ray |
| Drinking water |
5 millirem/year |
| Cross country round trip by air |
5 millirem per trip |
| Coal Burning power plant |
0.165 millirem/year |
"Epidemiological studies have not demonstrated
adverse health effects in individuals exposed to small doses (less than
10 rem) delivered in a period of many years."
....
Thus, the highest dose that will
normally be tolerated before control is definitely instituted is in the
range of a few tens of millisieverts (a few rems)although this may
be tolerated in successive years.
This covers:
· The permanent relocation
of people following an accident is recommended to avert a
dose of 1 Sv (100 rem) in a lifetime,
which corresponds to some 10s of mSv (several rem) in the first year,
· The occupational dose limit
of 20 mSv (2 rem) in a year,
· The upper (justified) action
level for radon in homes (10 mSv (1 rem) per year),
· A CT scan (~few 10s of
mSv (some few rems)), and
· The lower level of averted
dose above which evacuation is recommended after an
accident (50 mSv = 5 rem).
While these levels of dose to the
individual can hardly be called unacceptable, they are
levels at which questions should
be asked as to whether the dose and associated fatal risk which
will be of the order of 10-3
, or 1 in 1000 (per year), can be avoided by some sort of action. That
action may
be disruptive, or, as in the case
of a CT scan, be simply to question whether the required
information can be obtained by another
means involving lower dose.
Controllable doses should not generally
exceed this level and actual or potential doses
approaching this level would only
be allowed if the individual receives a benefit or the doses
cannot be reduced or prevented without
significant disruption to lifestyle.
At levels of controllable dose of
the order of a few millisieverts (a few 100 mrem) per year, the exposures
should not be of great concern from
the point of view of an individual’s health. Natural
background radiation is about
2-3 mSv (200 - 300 mrem) in a year, and even if radon exposures are excluded,
the figure is 1-2 mSv (100 - 200 mrem).
The exposures covered would be:
· the lower level of optimized
range for radon intervention (3 mSv),
· the lower level for simple
countermeasures (sheltering, KI) in an accident (5 mSv),
· the existing dose limit
for members of the pubic (1 mSv), and
· simple diagnostic x-ray
examinations ( 1 mSv)
Steps may be taken to reduce these
exposures, or to prevent them, particularly if the individual
receives no benefit. Thus from a
controllable dose of a few millisieverts upwards it becomes
increasingly desirable to reduce
or prevent the dose depending both on the practicability of doing
so and whether the individual is
deriving any tangible benefit from the exposure, e.g.. Annual
occupational exposures or medical
examination doses. The associated levels of fatal risk would
be 10-4, 1 in 10,000 (per year).
Doses that are below the millisievert
(100 mrem) level are also relevant in the control of exposures. In
connection with manmade uses of
radiation, the Commission has set the maximum dose from a
single new source to a member of
the public at 0.3 mSv a year. The associated level of fatal
cancer risk is about 10-5 per
year. This level of dose is about 10% of total natural background
dose and is also of the same order
as to variation in background radiation (excluding the radon
contribution) over much of the world.
A level of risk of death of 10
-6 per year is commonly regarded as trivial and the corresponding annual
dose of about 10-20 mSv
(1 - 2 mrem) has been used to set exemption
criteria for the Basic Safety Standards. At this level of dose there should
be no need to consider protection of the individual.
(local
link)
In setting the Max. Conc. Limits
for man-made beta and photon emitters, EPA used cancer risk estimates from
the BEIR I report for the U.S. population in the year 1967 (NAS, 1972).
For an exposed group having the same age distribution as the U.S. 1967
population, the BEIR I report indicated that the individual risk of a fatal
cancer from a lifetime total body dose rate of 4 mrem per year ranged from
about 0.4 to 2 x 10-6 per year depending on whether an absolute or relative
risk model was used. Using best estimates from both models for fatal cancer,
EPA believed that an individual risk of
-
0.8 x 10-6 per year resulting
from a 4 mrem annual total body dose
was a reasonable estimate of the annual
risk from a lifetime ingestion of drinking water.
(local
link)
Somatic effect means a health
effect on an exposed body. With regard to ionizing radiation,
somatic effects mainly refer to
cancers and leukemias (USEPA, 1981).
Stochastic effects means effects
for which the probability of occurrence is proportional to dose,
but not the severity of effect,
and it is assumed that there is no threshold below which they do not
occur (WHO, 1993).
Non-stochastic describes effects
whose severity is a function of dose; for these, a threshold may
occur. Examples of non-stochastic
somatic effects are cataract induction, nonmalignant damage
to the skin, hematological deficiencies,
and impairment of fertility (NIH, 1994). Non-stochastic
may also be referred to as deterministic
effects.
Stochastic means random events
leading to effects whose probability of occurrence in a exposed
population (rather than severity
in an affected individual) is a direct function of dose; these effects
are commonly regarded as having
no threshold; heredity effects are regarded as being stochastic;
some somatic effects, especially
carcinogens, are regarded as being stochastic (NIH, 1994).
version; May 27, 2006
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