ToxFAQs™ for Strontium
Spanish: Estroncio
CAS#: 7440-24-6
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This fact sheet answers the most frequently asked health questions about strontium. For more information, call the ATSDR Information Center at 1-800-232-4636. This fact sheet is one in a series of summaries about hazardous substances and their health effects. It is important you understand this information 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.
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.
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.
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.
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.
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.
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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.
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 doctor's office collects
and sends samples to a special lab for testing, or you must
go to the lab for testing.
Has the federal government made recommendations to protect human health?
EPA has set a limit of 4000 micrograms strontium per liter of drinking water (4000µg/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.
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.
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Where can I get more information?
If you have questions or concerns, please contact your community or state health or environmental quality department or:
For more information, contact:
Agency for Toxic Substances and Disease Registry
Office of Innovation and Analytics, Toxicology Section
4770 Buford Highway
Chamblee, GA 30341-3717
Phone: 1-800-CDC-INFO 888-232-6348 (TTY)
Email: Contact CDC-INFO
ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.