Radiation in the Environment L. Griffeth1, A. Orr1,

Radiation in the Environment L. Griffeth1, A. Orr1,

Radiation in the Environment
L. Griffeth1, A. Orr1, W. Splain1, J. Kelley1, D. Dasher2, S. Read2, and D. Barnes1
(1) University of Alaska Fairbanks, Fairbanks, Alaska 99775,
(2) Department of Environmental Conservation, Fairbanks, Alaska.
http://www.ims.uaf.edu/NEWNET/

RADIATION. For many, the word conjures up frightening images, such as
Chernobyl, Hiroshima, and deadly cancers. In reality, radiation surrounds us and most
forms do not cause us harm. It is in the foods we eat and the air we breathe. We touch
it, play with it, use it. On warm sunny days, we bask in it. It has the potential to
destroy lives but it is also used to save lives. What is Radiation, really?
Radiation is the transmission of energy in the form of light, or radiant heat from a body as it undergoes
internal changes. Radiation comes in many forms that fall into two categories, ionizing radiation and nonionizing radiation.
Types of Radiation:
Ionizing Radiation is a particle or wave high enough in energy to eject a charged particle from an
atom, in a process called ionization. There are many forms of ionizing
radiation with varying levels of energy and penetration potential
(Fig.1). The most common are alpha particles, beta particles,
gamma rays, and x-rays.
Alpha particles are helium nuclei. These are highly ionizing
particles that are emitted from the nucleus during the
decaying process of some radioactive elements. They are not
very penetrating and are usually stopped by as little as a
dead layer of skin. Nevertheless, if ingested or inhaled, alpha
particles can be very damaging, even deadly.
Beta particles are highly ionizing electrons, which are
[Fig. 1] A visual comparison of the penetration
emitted from the nucleus of some radioactive elements
potentials of different forms of ionizing radiation.
during the decaying process. These are more penetrating
Source: http://www.uic.com.au/
than the alpha particles and can usually be stopped by a layer
clothing.
However, if inhaled or ingested,
of
they can be very damaging and deadly.
There are many different units used to measure radiation.
Gamma rays are high energy waves in
However, the internationally preferred units are the International
the electromagnetic spectrum with no
System of Units (SI).
charge or mass. Along with beta and
The Gray (Gy) is used as a measurement of how much
alpha particles, they are emitted from the
radiation is absorbed by a body.
nuclei of some elements undergoing a
1 Gray = 1 Joule per kg of material
decaying process. Gamma rays are
The Sievert (Sv) is used as a measurement of not only the
highly penetrating and are only stopped
amount of radiation that is absorbed by a given body but it also
by several feet of concrete or lead,
takes into account quality (Q) of the radiation that is absorbed.
making gamma rays potentially more
For example, exposure to 1 Sievert of alpha radiation is more
harmful than the previous forms of
damaging than exposure to 1 Sievert of beta radiation in any
ionizing radiation.
given amount of time. Highly damaging radiation has a high
Non-Ionizing Radiation includes forms of
value for Q.
radiation such as ultraviolet light, visible
1 Sievert = 1 Gray * Q
light, infrared, microwaves, and radio waves.
The Becquerel (Bq) is used to measure radioactivity or the
The focus of this paper will be on ionizing
decaying of radioactive material.
radiation. Sources of Radiation
1 Becquerel = 1 disintegration per second.
**Disintegration is the transformation an element undergoes. For
Although radiation is present
example, Uranium-238 decays to Thorium-234 through alpha
everywhere and in everything, not all
emission.
radiation is normal for a given area. Normal
Common Unit Prefixes
Unit Conversions
radiation or background radiation is defined
-6
-11 Curie (Ci)
2.7
x
10
micro
()
10
1Bq
as the dose of radiation an individual is
milli (m)
10-3
1 Sv
100 REM*
subjected to in their daily environment,
whether man-made or naturally occurring.
kilo (k)
103
1 Gy
100 RAD**
Sources for background radiation are
mega (M)
106
1 Coulomb/kg
1 Roentgen (R)
dependent on factors such as elevation,
*Roentgen Equivalent Man, **Radiation Absorbed Dose
proximity to radiation emitting facilities, and
geologic makeup of area.
Non-background radiation is anything
above the normal radiation in a given area.
Examples are smoking, cancer treatments,
x-rays, and traveling in an aircraft (due to
increase in elevation).
Fallout from a nuclear explosion is
considered non-background radiation. Since
some of the radioactive material from
nuclear fallout have lengthy half-lives, over
time it becomes a part of background
radiation within a given environment.
[Fig.2] Right: Various Sources of Radiation.
As shown, common radioactive elements
such as potassium-40 are abundant not only
within the human body but in the foods we
eat. Source: www.uic.com.au, www.nei.org,
and "Radiation in the Environment" by ADEC.

*Indicates one of several types of radioactive elements used for medical purposes.

Radiation in Alaska has existed and
fluctuated since the earth first formed
billions of years ago. The sources that
have contributed to this pool of
radiation are both natural and manmade.
Radon-222 is a naturally occurring
gas. It is a type of radioactive
element that is produced as Uranium
(an unstable element) undergoes a
decaying process to a more stable
element. These types of elements are
abundant in areas containing granitic
rock. Areas in Alaska where this
occurs are:
Seward Peninsula
Eagle Creek (Death Valley)
Purcell Mountain
A harbor near Point Hope was to be
[Fig.4] Map showing geographic locations of places mentioned
constructed using nuclear explosives.
in the poster. Source: ADEC
Although the idea was dismissed, a
hydrological study was conducted shortly thereafter (1963). The study involved the spreading of small
amounts of radioactive tracer material (Cesium-137, 1.11 x 108 Bq), which was to be removed
immediately after the study. Instead, the material was left at location and buried. In 1993, the frozen
earth containing remnants of the tracer material was removed upon its discovery and disposed of
properly.
Three underground nuclear tests (in Table below) were conducted on Amchitka Island.
Project Year Est. Yield Depth (m)
Purpose
Longshot 1965
80kt
716
Seismic Testing
Milrow 1969
1 Mt
1220
Seismic Calibration
Cannikin 1971
5 Mt
1790
Device Testing
A nuclear power plant was constructed (1961) and operated at Fort Greely until 1971. The majority
of the material and parts were removed and disposed of, while the rest was buried on site and
encased in concrete until 1997 when a a leakage was detected. Cleanup and decommissioning of the
nuclearplant is still being done by the U.S. Army.
power
Bilibino, in the Russian far east, is the closest nuclear reactor to Alaska,
making it a potential threat. As with many of Russias nuclear power
plants, Bilibino uses old nuclear reactors. Should this plant suffer the
same fate as Chernobyl, a radioactive cloud could pass over Alaska with
potential for accumulation in the environment and subsistence food
supply.

What can we do about radiation? Radiation is everywhere. As a
community we must educate ourselves so we can make the right choices
regarding risk. To do this we should:
Know the sources, doses, and types of radiation in our surroundings.
Know how to protect ourselves adequately from unnecessary radiation
by monitoring the background radiation levels. This can be accomplished
by:
Operating small monitoring devices which can be purchased to
monitor radon levels in homes.
Maintaining long-term monitoring sites at the community level
(Fig.5).
Establishing a baseline level for gamma radiation to alert the
community about sudden increases in radiation should it occur.
[Fig.5] NEWNET
If exposure is unavoidable, individuals must:
(Neighborhood Environmental
Use appropriate protection.
Watch NETwork), uses these
Distance themselves from source.
towers to gather radiation and
Limit time of exposure to source.
meteorological data. This
References:
tower is located in Barrow.
1. http://www.epa.gov (2000)
2. http://www.nei.org (2001)
3. http://newnet.lanl.gov (2000)
Acknowledgements:
4. http://www.uic.com.au (2000)
This project is a collaborative effort
5. U.S. Department of Energy,
between the Battelle- Pacific Northwest
Office of Environmental
National Laboratory (PNNL), the Los
Alamos National Laboratory (LANL), the
Restoration and Waste
Alaska Department of Environmental
Management. (1991), Radiation
Conservation (ADEC), and the University
in the Environment.
of Alaska Fairbanks (UAF). We thank the
6. Hanson, W.C. and D.H. Dasher.
US Geologic Survey and the UAF
(1998), Radioactivity in Alaska.
Geology Department for their support.
[Fig.3] Radiation Source Distribution.
7. Shapiro, J. (1990), Radiation
We appreciate the support of the UAF
Other category includes source types such
chapter of American Indian Science and
Protection: A Guide for Scientists
as nuclear power, fallout, and food
Engineering Society (AISES).
and Physicians, Harvard
packaging.
University Press.
April 2001

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