Radium
ATSDR Public Health Statement, December 1990
This Statement was prepared to give you information about radium and
to emphasize the human health effects that may result from exposure to
it. The Environmental Protection Agency (EPA) has identified 1,177
sites on its National Priorities List (NPL). Radium has been found
above background levels at 18 of these sites. However, we do not know
how many of the 1,177 NPL sites have been evaluated for radium. As
EPA evaluates more sites, the number of sites at which radium is found
above background levels may change. The information is important for
you because radium may cause harmful health effects and because these
sites are potential or actual sources of human exposure to radium.
When a radioactive chemical is released from a large area, such as an
industrial plant, or from a container, such as a drum or bottle, it
enters the environment as a radioactive chemical emission. This
emission, which is also called a release, does not always lead to
exposure. You can be exposed to a radioactive chemical when you come
into contact with that chemical alone or with a substance that
contains it. You may be exposed to it in the environment by
breathing, eating, or drinking substances containing the radioactive
chemical or from skin contact with it. Exposure can also occur by
being near radioactive chemicals at concentrations that are found at
hazardous waste sites or industrial accidents.
If you are exposed to a hazardous substance such as radium, several
factors will determine whether harmful health effects will occur and
what the type and severity of those health effects will be. These
factors include the dose (how much), the duration (how long), the
route or pathway by which you are exposed (breathing, eating,
drinking, or skin contact), the other chemicals to which you are
exposed, and your individual characteristics such as age, sex,
nutritional status, family traits, life style, and state of health.
What is radium?
Radium is a naturally-occurring silvery white radioactive metal that
can exist in several forms called isotopes. It is formed when uranium
and thorium (two other natural radioactive substances) decay (break
down) in the environment. Radium has been found at very low levels in
soil, water, rocks, coal, plants, and food. For example, a typical
amount might be one picogram of radium per gram of soil or rock. This
would be about one part of radium in one trillion (1,000,000,000,000)
parts of soil or rock. These levels are not expected to change with
time.
Some of the radiation from radium is constantly being released into
the environment. It is this release of radiation that causes concern
about the safety of radium and all other radioactive substances. Each
isotope of radium releases radiation at its own rate. One isotope,
radium-224 for example, releases half of its radiation in about three
and a half days; whereas another isotope, radium-226, releases half of
its radiation in about 1,600 years.
When radium decays it divides into two parts. One part is called
radiation, and the second part is called a daughter. The daughter,
like radium, is not stable; and it also divides into radiation and
another daughter. The dividing continues until a stable,
nonradioactive daughter is formed. During the decay process, alpha,
beta, and gamma radiations are released. Alpha particles can travel
only a short distance and cannot travel through your skin. Beta
particles can penetrate through your skin, but they cannot go all the
way through your body. Gamma radiation, however, can go all the way
through your body. Thus, there are several types of decay products
that result from radium decay.
How might I be exposed to radium?
Because radium is present, usually at very low levels, in the
surrounding environment, you are always exposed to it and to the small
amounts of radiation that it releases to its surroundings. You may be
exposed to higher levels of radium if you live in an area where it is
released into the air from the burning of coal or other fuels, or if
your drinking water is taken from a source that is high in natural
radium, such as a deep well, or from a source near a radioactive waste
disposal site.
Levels of radium in public drinking water are usually less than one
picocurie per liter of water (about one quart), although higher levels
(more than 5 picocuries per liter) have been found. A picocurie (pCi)
is a very small amount of radioactivity, and it is associated with
about a trillionth of a gram (a picogram) of radium. (There are
approximately 28 grams in an ounce.) No information is available
about the amounts of radium that are generally present in food and
air. You may also be exposed to higher levels of radium if you work
in a uranium mine or in a plant that processes uranium ores.
How can radium enter and leave my body?
Radium can enter the body when it is breathed in or swallowed. It is
not known if it can be taken in through the skin. If you breathe
radium into your lungs, some may remain there for months; but it will
gradually enter the blood stream and be carried to all parts of the
body, especially the bones. For months after exposure, very small
amounts leave the body daily through the feces and urine.
If radium is swallowed in water or with food, most of it (about 80%)
will promptly leave the body in the feces. The other 20% will enter
the bloodstream and be carried to all parts of the body, especially
the bones. Some of this radium will then be excreted in the feces and
urine on a daily basis.
How can radium affect my health?
The Environmental Protection Agency (EPA) has determined that radium
is a human carcinogen. There is no clear evidence that long-term
exposure to radium at the levels that are normally present in the
environment (for example, 1 pCi of radium per gram of soil) is likely
to result in harmful health effects. However, exposure to higher
levels of radium over a long period of time may result in harmful
effects including anemia, cataracts, fractured teeth, cancer
(especially bone cancer), and death. Some of these effects may take
years to develop and are mostly due to gamma radiation. Radium gives
off gamma radiation, which can travel fairly long distances through
air. Therefore, just being near radium at the high levels that may be
found at some hazardous waste sites may be dangerous to your
health.
What levels of exposure have resulted in harmful health effects?
Radium has been shown to cause adverse health effects such as anemia,
cataracts, fractured teeth, cancer and death. As shown in Tables 1-1, 1-2, 1-3, and 1-4,
the relationship between the amount of radium that you are exposed to
and the amount of time necessary to produce these effects is not
known. Although there is some uncertainty as to how much exposure to
radium increases your chances of developing a harmful health effect,
the greater the total amount of your exposure to radium, the more
likely you are to develop one of these diseases.
Is there a medical test to determine whether I have been exposed
to radium?
There are few medical tests to determine if you have
been exposed to radium. There is a urine test to determine if you
have been exposed to a source of radioactivity such as radium. There
is also a test to measure the amount of radon, a breakdown product of
radium, when it is exhaled. These tests require special equipment and
cannot be done in a doctor's office. Another test can measure the
total amount of radioactivity in the body; however, this test is not
used except in special cases of high exposure.
What recommendations has the federal government made to protect human health?
EPA regulates the amount of radium in drinking water so that it will
not contain more than 5 pCi of combined radium-226 and radium-228 per
liter of water. The amount of radioactivity from all sources that is
allowed in drinking water and the amount that workers may be exposed
to in nuclear plants is regulated.