Public Health Statement for Tin
Spanish: Estaño
CAS#: 7440-31-5
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This Public Health Statement is the summary chapter from the Toxicological Profile for Tin. It is one in a series of Public Health Statements about hazardous substances and their health effects. A shorter version, the ToxFAQsTM, is also available. 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. For more information, call the ATSDR Information Center at 1-800-232-4636.
This public health statement tells you about tin and tin compounds and the effects of exposure to them.
The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites are then placed on the National Priorities List (NPL) and are targeted for long-term federal clean-up activities. Tin and organotin compounds have been found in at least 214 and 8, respectively, of the 1,662 current or former NPL sites. Although the total number of NPL sites evaluated for these substances is not known, the possibility exists that the number of sites at which tin and organotin compounds are found may increase in the future as more sites are evaluated. This information is important because these sites may be sources of exposure and exposure to these substances may harm you.
When a substance is released either from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment. Such a release does not always lead to exposure. You can be exposed to a substance only when you come in contact with it. You may be exposed by breathing, eating, or drinking the substance, or by skin contact.
If you are exposed to tin and tin compounds, many factors will determine whether you will be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with them. You must also consider any other chemicals you are exposed to and your age, sex, diet, family traits, lifestyle, and state of health.
What are tin and tin compounds?
Tin is a soft, white, silvery metal that is insoluble in water. Tin metal is used to line cans for food, beverages, and aerosols. It is present in brass, bronze, pewter, and some soldering materials.
Tin is a metal that can combine with other chemicals to form various compounds. When tin is combined with chlorine, sulfur, or oxygen, it is called an inorganic tin compound. Inorganic tin compounds are found in small amounts in the earth's crust. They are also present in toothpaste, perfumes, soaps, coloring agents, food additives, and dyes.
Tin also can combine with carbon to form organotin compounds. These compounds are used in making plastics, food packages, plastic pipes, pesticides, paints, wood preservatives, and rodent (rats and mice) repellants.
There can be tin metal as well as inorganic and organic tin compounds in the air, water, and soil near places where they are naturally present in the rocks, mined, manufactured, or used. In general, organic tin compounds are from human-made sources and do not occur naturally in the environment. The time each tin compound stays in air, water, or soil differs from compound to compound.
What happens to tin and tin compounds when they enter the environment?
Tin is a component of many soils. Tin may be released in dusts from wind storms, roads, and farming activities. Gases, dusts, and fumes containing tin may be released from smelting and refining processes, burning of waste, and burning of fossil fuels (coal or oil). Particles in the air containing tin may be transported by wind or washed out of the air by rain or snow. Tin binds to soils and to sediments in water and is generally regarded as being relatively immobile in the environment. Tin cannot be destroyed in the environment. It can only change its form or become attached or separated from particles in soil, sediment, and water.
Organic tin compounds stick to soil,
sediment, and particles in water. Organic tin compounds can
be degraded (by exposure to sunlight and by bacteria) into
inorganic tin compounds. In water, organic tin compounds are
mostly attached to particles in water. Organic tin compounds
may also settle out of the water into sediments and may remain
unchanged for years. Organic tin compounds may be taken up
into the tissues of animals that live in water containing
these compounds.
How might I be exposed to tin and tin compounds?
Tin is present in the air, water, soil,
and landfills and is a normal part of many plants and animals
that live on land and in water. Tin is also present in the
tissues of your body. There is no evidence that tin is an
essential element for humans.
Since tin is naturally found in soils,
it will be found in small amounts in foods. Tin concentrations
of vegetables, fruits and fruit juices, nuts, dairy products,
meat, fish, poultry, eggs, beverages, and other foods not
packaged in metal cans are generally less than 2 parts per
million (ppm) (1 ppm = 1 part of tin in a million parts of
food by weight). Tin concentrations in pastas and breads have
been reported to range from less than 0.003 to 0.03 ppm. You
can be exposed to tin when you eat food or drink juice or
other liquids from tin-lined cans. Canned food from lacquered
tin-lined cans contains less than 25 ppm of tin since the
lacquer prevents the food from reacting with the tin. Food
from unlacquered tin-lined cans contains up to 100 ppm of
tin since the reaction of the food with the can causes some
of the tin to dissolve in the contents of the can. Greater
than 90% of tin-lined cans used for food today are lacquered.
Only light colored fruit and fruit juices are packed in unlacquered
tin-lined cans, since tin helps maintain the color of the
fruit. Tin concentrations in food also increase if food is
stored in opened cans. Stannous fluoride, a tin-containing
compound, is added to toothpaste.
You can also be exposed to higher-than-normal
levels of tin if you work in a factory that makes or uses
tin. Because tin compounds have many uses, you can be exposed
by breathing in tin dusts or fumes or getting tin compounds
on your skin. Tin compounds can also be spilled accidentally.
If you live near a hazardous waste site, you could be exposed
by breathing dusts, touching materials, or drinking water
contaminated with tin.
Humans are usually exposed to tin at
far less than 1 ppm from air and water. The amounts in air
and water near hazardous waste sites could be higher.
Young children sometimes eat soil during
play. While most soil contains about 1 ppm tin, some soils
may contain as much as 200 ppm tin. Assuming that children
eat 200 mg of soil per day, exposure to tin from eating soil
would be low.
You may be exposed to organic tin compounds
(mainly butyltin compounds) by eating seafood from coastal
waters or from contact with household products that contain
organotin compounds, (polyurethane, plastic polymers, and
silicon-coated baking parchment paper). Organic tin compounds
have been detected in drinking water in Canada where pipes
made of polyvinyl chloride (PVC), which contain organic tin
compounds, are used in the distribution of drinking water.
How can tin and tin compounds enter and leave my body?
Tin can enter your body when you eat
contaminated food or drink contaminated water, when you touch
or eat soil that has tin in it, or when you breathe tin-containing
fumes or dusts. Tin compounds can enter your body from nearby
hazardous waste sites by exposure to contaminated air, water,
and soil. When you eat tin in your food, very little leaves
the gastrointestinal tract and gets into your bloodstream.
Most tin travels through the intestines and leaves your body
in the feces. Some leaves your body in the urine. If you breathe
air containing tin dust or fumes, some of the tin could be
trapped in your lungs, but this does not affect your breathing
if it is a small amount. If you swallow some metallic tin
particles, they will leave your body in the feces. Very little
tin can enter the body through unbroken skin. Your body can
rid itself of most inorganic tin in weeks, but some can stay
in your body for 2-3 months. Inorganic tin compounds leave
your body very quickly; most are gone within a day. Very small
amounts of tin stay in some tissues of your body, like the
bones, for longer periods of time.
How can tin and tin compounds affect my health?
Scientists use many tests to protect
the public from harmful effects of toxic chemicals and to
find ways for treating persons who have been harmed.
One way to learn whether a chemical will
harm people is to determine how the body absorbs, uses, and
releases the chemical. For some chemicals, animal testing
may be necessary. Animal testing may also help identify health
effects such as cancer or birth defects. Without laboratory
animals, scientists would lose a basic method for getting
information needed to make wise decisions that protect public
health. Scientists have the responsibility to treat research
animals with care and compassion. Scientists must comply with
strict animal care guidelines because laws today protect the welfare of research animals.
Because inorganic tin compounds usually
enter and leave your body rapidly after you breathe or eat
them, they do not usually cause harmful effects. However,
humans who swallowed large amounts of inorganic tin in research
studies suffered stomachaches, anemia, and liver and kidney
problems. Studies with inorganic tin in animals have shown
similar effects to those observed in humans. There is no evidence
that inorganic tin compounds affect reproductive functions,
produce birth defects, or cause genetic changes. Inorganic
tin compounds are not known to cause cancer.
Inhalation (breathing in), oral (eating
or drinking), or dermal exposure (skin contact) to some organotin
compounds has been shown to cause harmful effects in humans,
but the main effect will depend on the particular organotin
compound. There have been reports of skin and eye irritation,
respiratory irritation, gastrointestinal effects, and neurological
problems in humans exposed for a short period of time to high
amounts of certain organotin compounds. Some neurological
problems have persisted for years after the poisoning occurred.
Lethal cases have been reported following ingestion of very
high amounts. Studies in animals have shown that certain organotins
mainly affect the immune system, but a different type primarily
affects the nervous system. Yet, there are some organotins
that exhibit very low toxicity. Exposure of pregnant rats
and mice to some organotin compounds has reduced fertility
and caused stillbirth, but scientists still are not sure whether
this occurs only with doses that are also toxic to the mother.
Some animal studies also suggested that reproductive organs
of males may be affected. There are no studies of cancer in
humans exposed to organotin compounds. Studies of a few organotins
in animals suggest that some organotin compounds can produce
cancer. On the basis of no data in humans and questionable
data from a study in rats, EPA has determined that one specific
organotin, tributyltin oxide, is not classifiable as to human
carcinogenicity; that is, it is not known whether or not it causes cancer in humans.
How can tin and tin compounds affect children?
This section discusses potential health
effects in humans from exposures during the period from conception
to maturity at 18 years of age.
Children can be exposed to tin compounds
(inorganic or organic) in the same manner as adults: through
the diet or by contact with contaminated soil at or near hazardous
waste sites where these compounds are found. Some children
eat significant amounts of dirt (a behavior called pica),
which may lead to increased exposure if the soil is contaminated.
In addition, children can be exposed if family members work
with tin compounds and bring home tin residues in their clothing
or tools.
There are no studies on health effects
in children exposed to tin compounds. However, it is reasonable
to assume that children would exhibit the same type of health
effects observed in exposed adults. We do not know whether
children are more susceptible to the effects of exposure to
tin and tin compounds than adults. There are no reports of
adverse developmental effects in humans exposed to tin or
its compounds, or of inorganic tin in animals. Studies in
animals have shown that organotin compounds can cross the
placenta and reach the fetus. Exposure of rodents to some
organotins during pregnancy has produced birth defects in
the newborn animals. The results of several studies suggest
that this may occur only at high exposure levels that cause
maternal toxicity, but further research is needed to clarify
this issue. One study found that rats whose mothers were exposed
to tributyltin during pregnancy showed altered performance
in some neurological tests conducted when they were young
adults. Another study, also with tributyltin, found that exposure
during gestation, lactation, and post-lactation affected some
developmental landmarks in female rats. There are no reports
of tin or tin compounds in human breast milk, and there is
no direct evidence in animals of transfer of these compounds
to the young through nursing.
How can families reduce the risk of exposure to tin and tin compounds?
If your doctor finds that you have been
exposed to substantial amounts of tin and tin compounds, ask
whether your children might also have been exposed. Your doctor
might need to ask your state health department to investigate.
Children living near waste sites containing
tin and tin compounds are likely to be exposed to higher than
normal environmental levels of tin through breathing, touching
soil, and eating contaminated soil. You should discourage
your children from eating dirt. Make sure they wash their
hands frequently and before eating. Discourage your children
from putting their hands in their mouths. Some toothpastes
and other dental products contain stannous fluoride, a tin
containing compound. Children should be watched carefully
when using these products and should not swallow these products.
Because tin is naturally found in the
environment at low levels, we cannot avoid being exposed to
it. The major route of exposure to tin is from eating or drinking
canned products. Reducing the amount of canned products you
eat or drink may reduce your exposure to tin. Since tin concentrations
in food increase if food is stored in opened cans, you can
reduce your exposure by storing unused portions of canned
foods in a separate container. You may be exposed to organic
tin compounds by eating seafood from areas that may be contaminated
with organic tin compounds or from contact with household
products that contain organotin compounds (polyurethane, plastic
polymers, and silicon-coated baking parchment paper). Reducing
the amount of seafood that you eat from areas that may be
contaminated with organic tin compounds and reducing contact
with household products that contain organic tin compounds
may reduce your exposure to organic tin compounds. If you
are accidentally exposed to large amounts of tin or tin compounds,
consult a physician immediately.
Is there a medical test to determine whether I have been exposed
to tin and tin compounds?
There are tests to measure tin and organotin compounds in
your blood, urine, feces, and body tissues. Normally, small
amounts of tin are found in the body because of the daily
exposure to small amounts in the food. Therefore, the available
tests cannot tell you when you were exposed or the exact amount
of tin to which you were exposed, but can help determine if
you were exposed to an amount of tin or tin compounds unusually
high in the near past. This information can be used to locate
the source of exposure.
Tests for tin and related compounds are not routinely performed
at a doctor's office because they require special equipment,
but the doctor can take samples and send them to a testing
laboratory.
What recommendations has the federal government made to protect human health?
The federal government develops regulations
and recommendations to protect public health. Regulations
can be enforced by law. The EPA, the Occupational Safety and
Health Administration (OSHA), and the Food and Drug Administration
(FDA) are some federal agencies that develop regulations for
toxic substances. Recommendations provide valuable guidelines
to protect public health, but cannot be enforced by law. The
Agency for Toxic Substances and Disease Registry (ATSDR) and
the National Institute for Occupational Safety and Health
(NIOSH) are two federal organizations that develop recommendations
for toxic substances.
Regulations and recommendations can be
expressed as "not-to-exceed" levels, that is, levels
of a toxic substance in air, water, soil, or food that do
not exceed a critical value that is usually based on levels
that affect animals; they are then adjusted to levels that
will help protect humans. Sometimes these not-to-exceed levels
differ among federal organizations because they used different
exposure times (an 8-hour workday or a 24-hour day), different
animal studies, or other factors.
Recommendations and regulations are also
updated periodically as more information becomes available.
For the most current information, check with the federal agency
or organization that provides it. Some regulations and recommendations
for tin and tin compounds include the following:
Several government agencies and the Congress
have acted to protect human health by regulating tin compounds.
The EPA has limited the use of certain organotin compounds
in paints. OSHA has established workplace exposure limits
of 0.1 milligrams per cubic meter of air (mg/m3) for organotin
compounds and 2 mg/m3 for inorganic tin compounds, except
oxides. NIOSH recommends workplace exposure limits of 2 mg/m3
for inorganic tin compounds, except for tin oxides, and 0.1
mg/m3 for organotins, except tricyclohexyltin hydroxide. NIOSH
states that a concentration of tricyclohexyltin hydroxide
of 25 mg/m3 should be considered as immediately dangerous
to life or health. The FDA regulates the use of some organic
tin compounds in coatings and plastic food packaging. The
FDA also has set limits for the use of tin, as stannous chloride,
as an additive for food.
References
Agency for Toxic Substances and Disease Registry (ATSDR).
2005. Toxicological profile for
Tin. Atlanta, GA: U.S. Department of Health and Human Services,
Public Health Service.
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
Division of Toxicology and Human Health Sciences
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.