Arsenic Poisoning Symptoms & Signs
Arsenic poisoning is caused by exposure to the element arsenic. Arsenic can be present in a metallic state in three forms (yellow, black, and gray) and in ionic forms. Arsenic is considered to be a heavy metal, and arsenic toxicity shares some similarities with poisonings by other heavy metals. Arsenic is used to manufacture weed killers and insecticides.
Signs and symptoms of arsenic poisoning include
- abdominal pain,
- dark urine, and
What is arsenic?
Arsenic is a grey-appearing chemical element (atomic number 33, symbol As in
the periodic table) also termed a metalloid. Arsenic can exist in a metallic
state in three forms (yellow, black, and gray; with gray predominating) and in
ionic forms. Arsenic is considered to be a heavy metal, and arsenic toxicity
shares some features with poisonings by other heavy metals. Historically,
arsenic has been used as a medicinal agent, a pigment, a pesticide, and an agent
with intent to harm (use with criminal intent). Up until 2003, arsenic (in the
form of chromated copper arsenate) was used in the US as a treatment to prevent
insect infestation of wood used in building. In 2003 the use of this compound
was banned by the US Environmental Protection Agency.
Arsenic is mixed with
copper or lead to strengthen alloys containing these materials. Arsenic and some
of its compounds react with proteins, mainly the thiol portions, and uncouples
the process of oxidative phosphorylation, thus inactivating most cellular
functions. Consequently, arsenic and some of the substances it combines with are
deadly poisons to most biologic systems, except for a few bacterial species.
Arsenic is used in making insecticides and weed killers. Arsenic is also thought
to be carcinogenic, meaning that it has the potential to
can be found as a contaminant in food and water sources. Shellfish and other
seafood, as well as fruits, vegetables, and rice; are the foods most commonly
contaminated. Arsenic poisoning typically occurs as a result of industrial
exposure, from contaminated wine or illegally distilled spirits, or in cases of
What's Inside Your Drinking Water?
What is inorganic arsenic?
Inorganic arsenic is metallic or a metalloid element that forms a number of poisonous compounds. In industry, it can be found in a gaseous form termed arsine gas that is very toxic when inhaled. Inorganic arsenic is found in nature at low levels mostly compounded with oxygen, chlorine, and sulfur. These are called inorganic arsenic compounds. Inorganic arsenic compounds are much more poisonous to most biologic systems (animals, plants, humans) than organic arsenic (see below). Inorganic arsenic occurs in nature in the soil, copper and lead ore deposits, and water, but usually in low concentrations. However, it can become more concentrated when industrial processes use it to make wood preservatives, metal compounds, or organic arsenic-containing compounds such as insecticides, weed killers, and other compounds. If such compounds are burned, inorganic arsenic can be released into the air and later settle on the ground or in water and either remain in the inorganic form or combine with organic material.
What is organic arsenic?
Organic arsenic is any compound that is made from a chemical combination of
the element arsenic with any organic compound (compounds containing a large
amount of carbon). These are often termed arsenical organic compounds. Most
frequently organic arsenic is a component used in making insecticides and weed
killers and other compounds. Organic arsenic usually is not poisonous to humans
but may be poisonous to humans in high concentrations. In general, organic
arsenic is usually far less poisonous than inorganic arsenic.
What are the symptoms of arsenic poisoning?
People can be exposed to arsenic by inhaling it, by consuming contaminated
foods, water, or beverages, or by skin contact. We are normally exposed to trace
amounts of arsenic in the air and water, and in foods. People may be exposed to
higher levels if they live near industrial areas that currently or formerly
contained arsenic compounds. Areas with known high concentrations of arsenic in
the drinking water are also associated with greater exposure.
Acute or immediate symptoms of a toxic level of exposure to arsenic may
include the following:
Long-term exposures to arsenic lower than toxic levels can lead to skin
changes (darkening or discoloration, redness, swelling and hyperkeratosis (skin
bumps that resemble corns or warts). Whitish lines (Mees' lines) may appear in
the fingernails. Both sensory and motor nerve defects can develop. Additionally,
liver and kidney function may be affected.
Arsenic exposure over the long-term has also been associated with the
development of certain cancers, and arsenic has been classified as a carcinogen
by the Environmental Protection Agency (EPA). Studies of people in parts of
Southeast Asia and South America where there has been a high level of arsenic in
the drinking water have reported an increased risk of developing cancers of the
skin. Organic arsenic compounds are not as toxic as
inorganic compounds and are not believed to be linked to cancer.
How is arsenic poisoning diagnosed?
The history of the patient is very important as exposures are most often from
industrial accidents so other people (coworkers, rescue personnel) may be
exposed and not realize they may have some risk also. People exposed to toxic
levels of arsenic may have breath and urine that smells like garlic as a clue to
their diagnosis. Most doctors that suspect arsenic (or other metal or metalloid
poisonings) will request lab studies such as
blood cell counts and
serum electrolytes such as calcium and magnesium; if there is evidence of hemolysis
(blood cell destruction), a type and screening for a potential blood transfusion
There are rapid urine "spot" tests available to diagnose elevated
levels of arsenic, but they usually don't distinguish between organic and
inorganic arsenic. The patient's blood and urine will be sent for analysis for
arsenic; a result of > 50 micrograms/L is considered elevated, but acute toxic
exposures may result in levels 5 to 100 times or more than those which are
considered "elevated." A speciation test (determines levels of inorganic versus
organic arsenic) is required in all cases in which total urine arsenic is
elevated since inorganic arsenic is so toxic.
Electrocardiograms (ECG, EKG) and
nerve conduction tests
are often done in any type of suspected arsenic exposure. Tests for other toxins
or toxic overdoses (for example, Tylenol ingestion) may also be done.
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How is arsenic poisoning treated?
Acute toxic inorganic arsenic exposure and arsine gas exposure can rapidly result in death, and there are only a few ways to possibly save the patient's life. Hemodialysis can remove arsenic from the bloodstream, but only before it binds to the tissues so there is only a short time window for this treatment to work. Similarly, arsine binds to and causes rapid destruction of red blood cells, so blood transfusions and exchange transfusions may help the patient. In addition, if the arsenic was ingested, stomach or bowel irrigation may be attempted, but there is no good data to indicate these will be successful. Consultation with a nephrologist and a toxicologist as soon as possible is recommended; other consultants may need to be called (hematologist, psychiatrist, or others).
Chelation therapy (the use of drugs that selectively bind and effectively inactivate substances) is usually begun quickly through an intravenous line. The drug and the bound arsenic is then excreted through the urine. The chelation drug of choice is Dimercaprol (also termed BAL in oil); Succimer (DMSA) has also been used successfully, and Dimerval (DMPS) may also work as a chelator, but it is not readily available in the US.
What is the prognosis (outcome) of arsenic poisoning?
If the patient survives an acute toxic exposure, most will develop some
degree of nerve damage to the peripheral nerves (sensory and motor
disturbances); many survivors may have cardiac, liver, renal, and skin problems;
the prognosis is fair to poor. Chronic poisoning and organic arsenic exposure
have better outcomes with fewer and less severe problems.
In what foods (rice), products (apple juice), or liquids (water) is arsenic found, where it is used, and what are safe limits?
People may be exposed through work in a metal foundry, mining, glass production, the semiconductor industry, in criminal attempts at murder by poisoning, suicide attempts, and as a biological warfare agent.
- Arsenic has been found to contaminate such common items as wine, glues, and pigments.
- Arsenic is commonly found in many foods both in its relatively nontoxic organic form, and also in the more toxic inorganic form. Consequently, such foods need to be tested for both inorganic and organic arsenic levels.
- Arsenic has been reported in milk and dairy products, beef, pork, poultry, and cereal.
- Arsenic is also often found in rice, representing a potentially serious source of exposure in certain at-risk populations (especially children).
- Many water sources in the world have high levels of arsenic in them, both due to normal arsenic leaching out of the ground and from mining and industrial waste.
Recent examples of concerns about arsenic have surfaced because of its presence in apple juice. In most studies, various sources of apple juice tested by government and consumer labs have found that most (over 95% tested) contain a very small amount of arsenic (less than 10 parts per billion) and are safe to drink (in contrast to a TV show that raised alarms about consuming apple juice). However, the FDA qualified their findings by indicating in July 2013, new standards would apply and any juice that contained 10 or more parts per billion (the same level set for safe groundwater) would not be permitted to be sold in the US. This is lower than the previous approved level of less than 23 parts per billion approved in 2008. Nonetheless, other groups suggest that only juice containing less than 3 parts per billion be FDA approved.
Two other sources of arsenic, especially of some concern for children, is arsenic in groundwater and subsequently, in rice that is grown in such groundwater. Rice is a common food for children but to date, there are no regulations about the levels of arsenic that are considered safe for consumption. The FDA and the EPA are currently collecting data to make a recommendation about safe levels but many groups are pushing the FDA to act soon. The groups claim some private laboratories have detected that a single adult serving of some commercially available rice can give about 1.5 times the amount of permissible arsenic in one liter of water (under 10 parts per billion), so action on permissible arsenic levels should be done quickly. In 2013, the CDC recommends only about 2 cups of cooked rice per individual (adult) per week.
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Medically Reviewed on 7/31/2020
Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care
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