April 2004 |
ToxFAQs™ |
for |
Strontium |
(Estroncio) |
|
|
|
This fact sheet answers the most frequently
asked health questions about strontium. For more information,
you may call the ATSDR Information Center at 1-888-422-8737.
This fact sheet is one in a series of summaries about hazardous
substances and their health effects. This information is important
because this substance may harm you. The effects of exposure
to any hazardous substance depend on the dose, the duration,
how you are exposed, personal traits and habits, and whether
other chemicals are present.
|
|
HIGHLIGHTS: Exposure to stable
or radioactive strontium occurs from ingesting contaminated
food or drinking water or breathing contaminated air.
In children, high levels of stable strontium can impair
bone growth. High levels of radioactive strontium can
cause anemia or cancer. Strontium has been found in at
least 102 of the 1,636 National Priority List sites identified
by the Environmental Protection Agency. |
|
|
What
is strontium? |
Strontium is a naturally occurring element
found in rocks, soil, dust, coal, and oil. Naturally occurring
strontium is not radioactive and is either referred to as
stable strontium or strontium. Strontium in the environment
exists in four stable isotopes, 84Sr (read as strontium eighty-four),
86Sr, 87Sr, 88Sr.
Strontium compounds are used in making
ceramics and glass products, pyrotechnics, paint pigments,
fluorescent lights, and medicines.
Strontium can also exist as several radioactive
isotopes; the most common is 90Sr. 90Sr is formed in nuclear
reactors or during the explosion of nuclear weapons. Radioactive
strontium generates beta particles as it decays. One of the
radioactive properties of strontium is half-life, or the time
it takes for half of the isotope to give off its radiation
and change into another substance. The half-life of 90Sr is
29 years.
|
back to top |
|
What
happens to strontium when it enters the environment? |
- In air, strontium is present as dust, which eventually
settles over land and water.
- Some strontium compounds dissolve in water.
- Some strontium compounds in soil can dissolve in water
and move deeper in the soil to underground water.
- Radioactive decay and decontamination are the only ways
of decreasing the amount of 90Sr in the environment.
|
back to top |
|
How
might I be exposed to strontium? |
- You can be exposed to low levels of stable strontium
and radioactive strontium by breathing air, eating food,
or drinking water.
- Food and drinking water are the largest sources of exposure
to strontium.
- You can be exposed to radioactive strontium if you eat
food that was grown in contaminated soil, or if you come
near a source of radioactive strontium.
|
back to top |
|
How
can strontium affect my health? |
Exposure to low levels of stable strontium
has not been shown to affect adult health, but may harm children
(see following section).
Breathing or ingesting low levels of
radioactive strontium have not been shown to affect health.
High levels of radioactive strontium can damage bone marrow
and cause anemia and prevent the blood from clotting properly.
|
back to top |
|
How
likely is strontium to cause cancer? |
The only stable strontium compound that
may cause cancer is strontium chromate, but this is due to
chromium not strontium.
Exposure to high levels of radioactive
strontium may cause cancer. Leukemia has been seen in humans
exposed to relatively large amounts of radioactive strontium.
Leukemia and cancers of the bone, nose, lung, and skin have
also been seen in laboratory animals.
The International Agency for Research
on Cancer (IARC) has determined that radioactive strontium
is a human carcinogen.
|
back to top |
|
How
can strontium affect children? |
We do not know if exposure to strontium
will result in birth defects or other developmental effects
in people. Birth defects have been observed in animals exposed
to radioactive strontium.
Exposure to high levels of stable strontium
can result in impaired bone growth in children.
Children may be more susceptible than
adults to the harmful effects of radioactive strontium.
|
back to top |
|
How
can families reduce the risk of exposure to strontium? |
Having a balanced diet with sufficient
amounts of vitamin D, calcium, and protein will reduce the
amount of strontium that is absorbed.
|
back to top |
|
Is
there a medical test to show whether I've been exposed to strontium? |
All people have small amounts of stable
strontium in their bodies. There are tests to measure the
level of strontium in blood, hair, feces, and urine. These
tests are most useful for people exposed to high levels. These
tests cannot determine the exact levels of strontium you may
have been exposed to or predict how the levels in your tissues
will affect your health.
Two types of tests are available for
radioactive strontium. One is to see if you have been exposed
to a large dose of radiation, and the other is to see if strontium
is in your body. The first looks for changes in blood cell
counts or in your chromosomes that occur at 3 to 5 times the
annual occupational dose limit. It cannot tell if the radiation
came from strontium. The second type of test involves examining
your blood, feces, saliva, urine, teeth, and even your entire
body. It is to see if strontium is being excreted from your
body, is in your teeth, or remains inside your body at levels
that are higher than normal. The doctors office collects
and sends samples to a special lab for testing, or you must
go to the lab for testing.
|
back to top |
|
Has
the federal government made recommendations to protect human
health? |
EPA has set a limit of 4000 micrograms
strontium per liter of drinking water (4000 µg/L).
EPA has set a limit of 8 picocurie 90Sr
per liter of drinking water.
The Nuclear Regulatory Commission has
set limits for radioactive strontium in workplace air for
a 40-hour work week of 6x10-8 microcurie per milliliter (µCi/mL)
for 89Sr and 8x10-9 µCi/mL for 90Sr. EPA has set an
average annual drinking water limit of 20 picocuries per liter
(pCi/L) for 89Sr and 8 pCi/L for 90Sr so the public radiation
dose will not exceed 4 millirem.
|
back to top |
|
References |
Agency for Toxic Substances and Disease
Registry (ATSDR). 2004. Toxicological
Profile for strontium. Atlanta, GA: U.S. Department of
Health and Human Services, Public Health Service.
|
back to top |
|
Where can I get
more information? |
ATSDR can tell you where to find occupational
and environmental health clinics. Their specialists can recognize,
evaluate, and treat illnesses resulting from exposure to hazardous
substances. You can also contact your community or state health
or environmental quality department if you have any more questions
or concerns. For more information, contact:
|
Agency for Toxic Substances and Disease Registry
Division of Toxicology
1600 Clifton Road NE, Mailstop F-32
Atlanta, GA 30333
Phone: 1-888-42-ATSDR (1-888-422-8737)
FAX: (770)-488-4178
Email: ATSDRIC@cdc.gov
|
back to top |
|