Superfund Radiation Fact Sheet
What is Superfund? The Superfund program is administered by U.S. Environmental
Protection Agency (EPA) in cooperation with state and tribal governments. It allows
EPA to clean up hazardous waste sites and to force responsible parties to perform
cleanups or reimburse the government for cleanups led by EPA.
For a variety of reasons, hazardous
commercial and industrial wastes were
mismanaged and may pose unacceptable
risks to human health and the
environment. This waste was dumped on
the ground or in waterways, left out in
the open, or otherwise improperly
managed. As a result, thousands of
hazardous waste sites were created
throughout the United States. These
hazardous waste sites commonly include
manufacturing facilities, processing
plants, landfills, and mining sites.
Superfund was established in 1980 by an
act of Congress, giving EPA the funds and
authority to clean up polluted sites
Goals of SuDerfund:
•	Protect human health and the
environment by cleaning up
polluted sites
•	Involve communities in the
Superfund process
•	Make responsible parties pay for
work performed at Superfund
sites
..
Superfund is the informal name for the
Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA).
In 1980, Congress enacted CERCLA in
response to growing concerns over the
health and environmental risks posed by
hazardous waste sites. This law was
enacted in the wake of the discovery of
chemically contaminated toxic waste
dumps such as Love Canal and Valley of
the Drums in the 1970s.
Some Superfund sites contain radioactive
contamination. This document was
developed by EPA to answer questions
about radiation hazards and how EPA
assesses health risks from potential
exposure to radioactive contamination at
Superfund sites.
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What are atoms?
To understand radiation and
radioactivity, it is important to
understand atoms.
Atoms are the very small particles that
make up our bodies and everything
around us. Atoms consist of a central
nucleus made up of protons and
neutrons. Protons are positively charged,
while neutrons have no charge. Electrons
have a negative charge and orbit (or go
around) the nucleus. Most atoms are
neutral, which means they have the same
number of protons and electrons. Atoms
that are not neutral are called ions.
Atomic Structure
Neutron
Proton
Electron
An atom consists of a central nucleus (made
of protons and neutrons) orbited by
electrons
An element is a specific type of atom. All
atoms of an element have the same
number of protons. For example, all
atoms of oxygen have eight protons,
while all uranium atoms have 92 protons.
It is possible for atoms of the same
element to have different numbers of
neutrons. These various forms are called
isotopes. For example, while all atoms of
oxygen have eight protons, isotopes of
oxygen can have from four to 16
neutrons.
What is Radiation?
Radiation is energy that travels in the
form of waves or high-speed particles.
There are two types of radiation:
•	Non-ionizing radiation is low energy.
It includes radio waves, microwaves,
and visible light. Non-ionizing
radiation can generate heat, but it
does not have enough energy to
remove electrons from atoms.
•	Ionizing radiation is high energy. It
can remove tightly bound electrons
from an atom. Ionizing radiation can
be harmful to humans by damaging
living tissue and increasing cancer risk.
X-rays are a familiar form of ionizing
radiation.
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Common Types of Radiation
non-ionizing	ionizing
extremely
low
frequency
radio	infrared -£, ultraviolet
—>
x-ray
non-thermal
induces lov;
currents
microwave
<	H
thermal
optical
induces high
excitefl
currents
clcctrom
heating
photon

chemica

effects
gamma rays
broken bonds
damages
DNA
Static power
field line
AM FM radio mir.rowavo Ml'h: lann.-ng
radio TV oven lamp bootn
medical
x-rays
In this fact sheet, the term "radiation"
will mean ionizing radiation.
What is Rodioactivitv?
Some isotopes of certain atoms are
unstable. When these unstable atoms
release ionizing radiation in the form of
waves or particles, it is called
radioactivity. A radioactive atom is called
a radionuclide. When a radionuclide
emits (gives off) radiation, it is said to
decay. There are three main types of
radiation given off when a radionuclide
decays:
• Alpha particles are heavy, relatively
slow moving, particles. They can be
blocked by a piece of paper or by skin.
However, radionuclides that give off
alpha particles can be very harmful if
they enter your body in other ways
such as through the air, food, or water
because your internal organs are not
protected by skin.
Beta particles are light weight,
relatively fast moving particles. They
can be blocked by a thin piece of
metal or wood. Beta particles can
penetrate (pass through) the outer
layer of skin and cause radiation
burns. Like alpha particles, beta
particles can damage your health if
they enter your body.
Gamma rays are waves of pure energy
that often accompany beta and alpha
particles. Gamma rays can pass
through the body and damage internal
organs. A thick wall of metal or
concrete is needed to absorb gamma
radiation.
Radiation Penetrating Power
Alpha"
Beta
Gamma
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AAA
A/\y\
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Ionizing Radiation Found at Superfund Sites

Alpha Particles
Beta Particles
sO
Gamma Rays j



#

• Two protons and two
• Made up of an electron
• Pure energy traveling

neutrons bound together
ejected from nucleus
at the speed of light

into a single particle
• Fast moving, low mass
• Often accompanies
Description
• Heaviest and slowest
particle
the emission of alpha

moving type of ionizing
• Negatively charged
or beta particles

radiation

• Has no rest mass and

• Positively charged

no charge

• HIGH
• MODERATE
• LOW

• Interacts strongly with
• Interact less strongly
• Since they have no
Ionizing
surrounding material
than alpha particles but
mass and no charge,
Daiiia k
• Very energetic
more strongly than
gamma rays interact
rower

gamma rays with
with matter less than


surrounding material
alpha and beta



particles

• LOW
• MODERATE
• HIGH

• Travels no more than a
• Able to travel several
• Able to travel

few centimeters in air
meters through air
hundreds of meters
Penetrating
• Can be stopped by a sheet
• Can be stopped by a
through air
Power
of paper
thin layer of metal or
• Can be stopped by a

• Unable to penetrate skin
plastic
thick concrete wall


• Can penetrate outer
• Able to pass through


layers of skin
the human body

• No health effects from
• Can cause skin burns
• Can cause harm from

external exposure since
from external exposure
external exposure

they are unable to
• Harmful if taken into
• Can pass into the
Human
penetrate skin
the body (though not
body and cause
Health
• Very harmful if alpha-
usually as harmful as
internal radiation
Effects
emitting radionuclide is
alpha particles)
exposure
taken into the body by



ingestion/ breathing, or



through an open wound


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What happens to radionuclides as
&
fftey decay?
As radionuclides decay, they become new
elements called daughter products,
which are also known as decay products.
These daughter products may or may not
be radioactive themselves. If a daughter
product is aiso radioactive, it in turn will
decay to form a different daughter
product. This process will continue until a
stable, nonradioactive product is formed.
The radioactive decay of a radionuclide
and all of its daughters is known as a
decay chain.
What is half-life?
The rate a radionuclide decays is its half-
life. Half-life is defined as the amount of
time it takes for half of the amount of a
substance to emit radiation and change
to a different substance. Radionuclide
half-iives can be very long or very short.
For example, uranium-238 has a half-life
of 4.5 billion years, while carbon-11 has a
half-life of only a few minutes.
How is radioactivity measured?
Radioactivity is measured by the activity
of a material. The activity is the number
of radionuclides that decay each second.
EPA often uses a unit called a curie to
measure activity. One curie is 37 billion
decays per second. This unit is too large
to use at most Superfund sites to assess
radiation risk, so EPA usually uses a unit
called a picocurie. One picocurie is equal
to one trillionth of a curie, or about 2.2
radionuclide decays per minute.
EPA measures radioactive contamination
by the number of picocuries measured in
a specific amount of contaminated
material. Soil contamination, for
example, is measured in picocuries per
gram.
Why are radionuclides harmful to
human health?
The human body is made up of atoms.
When radionuclides decay, they release
alpha, beta, and gamma radiation. This
radiation can break the bonds between
the atoms, damaging living tissue and
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DNA. Usually, our bodies can repair this
type of damage, but sometimes there
may be too much damage to repair. This
damage to living tissue and DNA can lead
to cancer or other health effects. The risk
of cancer increases as exposure to
radiation increases.
How can you be exposed to harmful
radiation?
Radionuclides cause the most harm when
they are inside of the body. There are
three ways to be exposed to
radionuclides:
• Inhalation - Breathing contaminated
vapors, dust particles, or radon gas.
•	Ingestion - Eating contaminated food,
drinking contaminated water, or
accidentally ingesting small amounts
of contaminated dust or soil,
•	External - Radiation emitting out from
a source such as radioactively
contaminated soil or object, and then
penetrating from outside of the body.
How is radiation exposure
measured?
Under most situations, radiation
exposure is measured in dose. Dose is
related to the amount of radiation
absorbed by a person's body. The unit for
radiation dose that EPA uses is the
millirem. Millirem relates the absorbed
dose of radiation to the amount of
biological damage from the radiation.
However, radiation exposure at
Superfund sites is measured by cancer
risk. All radionuclides can cause cancer,
and the cancer risk increases as exposure
increases. Not all radiation has the same
biological effect, even when the absorbed
dose is the same, however. Therefore,
EPA's use of cancer risk accounts for the
different types of radiation as well as its
effects on different parts of the body.
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How does EPA calculate risks to
human health from radiation
exposure at Suoerfund sites?
EPA assesses the health effects of
radiation by calculating excess cancer risk
posed by radioactive contamination.
Excess cancer risk is the additional
probability that a person exposed to the
contamination will develop cancer over a
lifetime.
EPA considers excess cancer risk to be
any risk above the protective range. The
protective range is a probability that a
person exposed to radioactive and
chemical contaminants will have between
a one in ten thousand and a one in a
million chance of developing cancer,
known as the 10"4 to 10"6 cancer risk
range.
It is important to note that, even in the
protective range, most people will have
less of a chance of developing cancer
than these numbers indicate. EPA uses
assumptions about exposure levels that
are higher than most people's actual
exposure.
EPA may also calculate health risk from
radiation exposure in dose per year,
measured in millirem per year. Some
regulations at Superfund sites are based
on what EPA has calculated to be
acceptable dose limits per year.
What is background radiation?
Radiation is everywhere in our
environment. The average person in the
United States receives a radiation
exposure of approximately 620 millirems
per year from both natural and man-
made sources. For examples of radiation
in our environment, see the chart
"Relative Doses from Radiation Sources"
on page 9. These examples include
cosmic radiation from space, medical
procedures, radiation found naturally in
the soil and water, and indoor radon.
However, at Superfund sites, EPA is
comparing radioactive pollution at the
site with background radiation of the
same radionuclides where the pollution
occurs, such as in the soil and water.
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Some Common Ways to be Exposed to
Radionuclides at Contaminated Sites
Residential Soil Exposure
Breathing in Dust
Particles External
Exposure
Eating Fruits and
Vegetables
Incidental Soil
estion
Agricultural Soil Exposure
Breathing in Dust	Eating Fruits and
Particles	Consuming Vegetables
Fatinn Fi«?h Pork> Beef,
External c^,1 ken and and Milk	Incidental Soil
Ingestion

Soil to Ground Water Exposure
Drinking Water
Well
m
Leaching
Tap Water Exposure
Breathing in Vapors

Drinking Water

M
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RELATIVE DOSES FROM RADIATION SOURCES
Millirem Doses
Radon in average home
200 millirem
(annual)
Diagnostic radiology
50 millirem
(annual)
Mammogram
30 millirem
(single procedure)
Cosmic radioactivity
27 millirem
(annual)
Chest x-ray
4 millirem
(single procedure)
Mil

M
iiiii
Gastrointestinal series
1,400 millirem
(single procedure)
Cosmic radiation living
in Denver
50 millirem
(annual)
Natural radioactivity
in the body
40 millirem
(annual)
Terrestrial radioactivity
28 millirem
(annual)
Cosmic radiation living
at sea level
24 millirem (annual)
Living near a nuclear
power station
< 1 millirem on average
(annual)
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What if I want More Information?
If you would like to learn more about
EPA's Superfund program, you may want
to read the document "This is Superfund:
A Community Guide to EPA's Superfund
Program," available online at:
http://www.epa.gov/superfund/commun
itv/todav/pdfs/TIS%20FINAL%209.13.11.
pdf
If you have questions about this
document, you can contact Stuart Walker
of EPA by e-mail at
walker.stuart(5>epa.gov or by telephone
at (703) 603-8748.
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