September 2003 |
ToxFAQs™ |
for |
Zinc |
(Cinc) |
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This fact sheet answers the most frequently
asked health questions about zinc. 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.
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HIGHLIGHTS: Zinc is a naturally
occurring element. Exposure to high levels of zinc occurs
mostly from eating food, drinking water, or breathing
workplace air that is contaminated. Low levels of zinc
are essential for maintaining good health. Exposure to
large amounts of zinc can be harmful. It can cause stomach
cramps, anemia, and changes in cholesterol levels. Zinc
has been found in at least 953 of the 1,636 National Priority
List sites identified by the Environmental Protection
Agency (EPA). |
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What
is zinc? |
Zinc is one of the most common elements
in the earth's crust. It is found in air, soil, and water,
and is present in all foods. Pure zinc is a bluish-white shiny
metal.
Zinc has many commercial uses as coatings
to prevent rust, in dry cell batteries, and mixed with other
metals to make alloys like brass, and bronze. A zinc and copper
alloy is used to make pennies in the United States.
Zinc combines with other elements to
form zinc compounds. Common zinc compounds found at hazardous
waste sites include zinc chloride, zinc oxide, zinc sulfate,
and zinc sulfide. Zinc compounds are widely used in industry
to make paint, rubber, dyes, wood preservatives, and ointments.
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What
happens to zinc when it enters the environment? |
- Some is released into the environment by natural processes,
but most comes from human activities like mining, steel
production, coal burning, and burning of waste.
- It attaches to soil, sediments, and dust particles in
the air.
- Rain and snow remove zinc dust particles from the air.
- Depending on the type of soil, some zinc compounds can
move into the groundwater and into lakes, streams, and rivers.
- Most of the zinc in soil stays bound to soil particles
and does not dissolve in water.
- It builds up in fish and other organisms, but it does
not build up in plants.
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How
might I be exposed to zinc? |
- Ingesting small amounts present in your food and water.
- Drinking contaminated water or a beverage that has been
stored in metal containers or flows through pipes that have
been coated with zinc to resist rust.
- Eating too many dietary supplements that contain zinc.
- Working on any of the following jobs: construction, painting,
automobile mechanics, mining, smelting, and welding; manufacture
of brass, bronze, or other zinc-containing alloys; manufacture
of galvanized metals; and manufacture of machine parts,
rubber, paint, linoleum, oilcloths, batteries, some kind
of glass, ceramics, and dyes.
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How
can zinc affect my health? |
Zinc is an essential element in our diet.
Too little zinc can cause problems, but too much zinc is also
harmful.
Harmful effects generally begin at levels
10-15 times higher than the amount needed for good health.
Large doses taken by mouth even for a short time can cause
stomach cramps, nausea, and vomiting. Taken longer, it can
cause anemia and decrease the levels of your good cholesterol.
We do not know if high levels of zinc affect reproduction
in humans. Rats that were fed large amounts of zinc became
infertile.
Inhaling large amounts of zinc (as dusts
or fumes) can cause a specific short-term disease called metal
fume fever. We do not know the long-term effects of breathing
high levels of zinc.
Putting low levels of certain zinc compounds
on the skin of rabbits, guinea pigs, and mice caused skin
irritation. Skin irritation will probably occur in people.
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How
likely is zinc to cause cancer? |
The Department of Health and Human Services
(DHHS) and the International Agency for Research on Cancer
(IARC) have not classified zinc for carcinogenicity. Based
on incomplete information from human and animal studies, the
EPA has determined that zinc is not classifiable as to its
human carcinogenicity.
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How
can zinc affect children? |
Zinc is essential for proper growth and
development of young children. It is likely that children
exposed to very high levels of zinc will have similar effects
as adults. We do not know whether children are more susceptible
to the effects of excessive intake of zinc than the adults.
We do not know if excess zinc can cause
developmental effects in humans. Animal studies have found
increases in deaths and decreased weight in the offsprings
after ingesting very high amounts of zinc.
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How
can families reduce the risks of exposure to zinc? |
- Children living near waste sites that contain zinc may
be exposed to higher levels of zinc through breathing contaminated
air, drinking contaminated drinking water, touching or eating
contaminated soil.
- Discourage your children from eating soil or putting their
hands in their mouths and teach them to wash their hands
frequently and before eating.
- If you use medicines or vitamin supplements containing
zinc, make sure you use them appropriately and keep them
out of the reach of children.
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Is
there a medical test to determine whether I've been exposed
to zinc? |
There are tests available to measure
zinc in your blood, urine, hair, saliva, and feces. These
tests are not usually done in the doctor's office because
they require special equipment. High levels of zinc in the
feces can mean high recent zinc exposure. High levels of zinc
in the blood can mean high zinc consumption and/or high exposure.
Tests to measure zinc in hair may provide information on long-term
zinc exposure; however, the relationship between levels in
your hair and the amount of zinc you were exposed to is not
clear.
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Has
the federal government made recommendations to protect human
health? |
The EPA recommends that drinking water
should contain no more than 5 milligrams per liter of water
(5 mg/L) because of taste. The EPA requires that any release
of 1,000 pounds (or in some cases 5,000 pounds) be reported
to the agency.
To protect workers, the Occupational
Safety and Health Administration (OSHA) has set an average
limit of 1 mg/m³ for zinc chloride fumes and 5 mg/m³
for zinc oxide (dusts and fumes) in workplace air during an
8-hour workday, 40-hour workweek.
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References |
Agency for Toxic Substances and Disease
Registry (ATSDR). 2003. Toxicological Profile for Zinc (Draft
for Public Comment). Atlanta, GA: U.S. Department of Public
Health and Human Services, Public Health Service.
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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:
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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
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