Mercury poisoning is a disease caused by exposure to
mercuryMercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
or its
compoundsA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
. Mercury (chemical symbol Hg) is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses. Its zero
oxidation stateIn chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
HgMercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
0 exists as vapor or as liquid metal, its mercurous state Hg
+ exists as inorganic salts, and its mercuric state Hg
2+ may form either inorganic salts or
organomercuryOrganomercury refers to the group of organometallic compounds that contain mercury. Typically the Hg-C bond is stable toward air and moisture but sensitive to light. Important organomercury compounds are the methylmercury cation, CH3Hg+; ethylmercury cation, C2H5Hg+; dimethylmercury, 2Hg,...
compounds; the three groups vary in effects. Toxic effects include damage to the brain, kidney, and lungs. Mercury poisoning can result in several diseases, including acrodynia (pink disease), Hunter-Russell syndrome, and
Minamata disease', sometimes referred to as , is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death...
.
Symptoms typically include sensory impairment (vision, hearing, speech), disturbed sensation and a lack of coordination. The type and degree of symptoms exhibited depend upon the individual toxin, the dose, and the method and duration of exposure.
Signs and symptoms
Common symptoms of mercury poisoning include
peripheral neuropathyPeripheral neuropathy is the term for damage to nerves of the peripheral nervous system, which may be caused either by diseases of or trauma to the nerve or the side-effects of systemic illness....
(presenting as
paresthesiaParesthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
or itching, burning or
painPain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...
), skin discoloration (pink cheeks, fingertips and toes), swelling, and
desquamationDesquamation , also called skin peeling, is the shedding of the outermost membrane or layer of a tissue, such as the skin.-Skin:Normal, nonpathologic desquamation of the skin occurs when keratinocytes, after moving apically over about 14 days, are individually shed unnoticeably...
(shedding of skin).
Mercury is thought to inactivate S-adenosyl-methionine, which is necessary for catecholamine
catabolismCatabolism is the set of metabolic pathways that break down molecules into smaller units and release energy. In catabolism, large molecules such as polysaccharides, lipids, nucleic acids and proteins are broken down into smaller units such as monosaccharides, fatty acids, nucleotides, and amino...
by
catechol-o-methyl transferaseCatechol-O-methyltransferase is one of several enzymes that degrade catecholamines such as dopamine, epinephrine, and norepinephrine. In humans, catechol-O-methyltransferase protein is encoded by the COMT gene...
. Due to the body's inability to degrade catecholamines (e.g.
EpinephrineEpinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...
) a person suffering from mercury poisoning may experience profuse sweating,
tachycardiaTachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...
(persistently faster-than-normal heart beat), increased salivation, and
hypertensionHypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
(high blood pressure).
Affected children may show red
cheekCheeks constitute the area of the face below the eyes and between the nose and the left or right ear. They may also be referred to as jowls. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve...
s,
noseThe visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...
and lips, loss of
hairHair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....
, teeth, and
nailsA nail is a horn-like envelope covering the dorsal aspect of the terminal phalanges of fingers and toes in humans, most non-human primates, and a few other mammals. Nails are similar to claws, which are found on numerous other animals....
, transient rashes,
hypotoniaHypotonia is a state of low muscle tone , often involving reduced muscle strength. Hypotonia is not a specific medical disorder, but a potential manifestation of many different diseases and disorders that affect motor nerve control by the brain or muscle strength...
(muscle weakness), and increased sensitivity to light. Other symptoms may include
kidneyThe kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
dysfunction (e.g.
Fanconi syndromeFalconi syndrome is a disease of the proximal renal tubules of the kidney in which glucose, amino acids, uric acid, phosphate and bicarbonate are passed into the urine, instead of being reabsorbed. Fanconi syndrome affects the proximal tubule, which is the first part of the tubule to process fluid...
) or neuropsychiatric symptoms such as emotional lability,
memoryIn psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
impairment, or
insomniaInsomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
.
Thus, the clinical presentation may resemble
pheochromocytomaA pheochromocytoma or phaeochromocytoma is a neuroendocrine tumor of the medulla of the adrenal glands , or extra-adrenal chromaffin tissue that failed to involute after birth and secretes excessive amounts of catecholamines, usually noradrenaline , and adrenaline to a lesser extent...
or
Kawasaki diseaseKawasaki disease , also known as Kawasaki syndrome, lymph node syndrome and mucocutaneous lymph node syndrome, is an autoimmune disease in which the medium-sized blood vessels throughout the body become inflamed. It is largely seen in children under five years of age...
.
An example of
desquamationDesquamation , also called skin peeling, is the shedding of the outermost membrane or layer of a tissue, such as the skin.-Skin:Normal, nonpathologic desquamation of the skin occurs when keratinocytes, after moving apically over about 14 days, are individually shed unnoticeably...
of the hand of a child with severe mercury poisoning acquired by handling elemental mercury is
this photograph in Horowitz,
et al. (2002).
Causes
The
consumption of fishFish and shellfish concentrate mercury in their bodies, often in the form of methylmercury, a highly toxic organic compound of mercury. Fish products have been shown to contain varying amounts of heavy metals, particularly mercury and fat-soluble pollutants from water pollution...
is by far the most significant source of ingestion-related mercury exposure in humans and animals, although plants and livestock also contain mercury due to
bioaccumulationBioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost...
of mercury from soil, water and atmosphere, and due to
biomagnificationBiomagnification, also known as bioamplification or biological magnification, is the increase in concentration of a substance that occurs in a food chain as a consequence of:* Persistence...
by ingesting other mercury-containing organisms. Exposure to mercury can occur from breathing contaminated air, from eating foods that have acquired mercury residues during processing, from exposure to mercury vapor in mercury amalgam dental restorations, and from improper use or disposal of mercury and mercury-containing objects, for example, after spills of elemental mercury or improper disposal of
fluorescent lampA fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful...
s.
Consumption of whale and dolphin meat, as is the practice in
JapanJapan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
, is a source of high levels of mercury poisoning. Tetsuya Endo, a professor at the Health Sciences University of Hokkaido, has tested whale meat purchased in the whaling town of Taiji and found mercury levels that are more than 20 times acceptable Japanese standards.
Human-generated sources such as coal plants emit approximately half of atmospheric mercury, with natural sources such as
volcano2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
es responsible for the remainder. An estimated two-thirds of human-generated mercury comes from stationary combustion, mostly of
coalCoal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...
. Other important human-generated sources include
gold productionGold mining is the removal of gold from the ground. There are several techniques and processes by which gold may be extracted from the earth.-History:...
,
non-ferrous metalIn metallurgy, a non-ferrous metal is a metal that is not ferrous, that is, any metal, including alloys, that does not contain iron in appreciable amounts...
production,
cementIn the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...
production, waste disposal, human crematoria, caustic soda production,
pig ironPig iron is the intermediate product of smelting iron ore with a high-carbon fuel such as coke, usually with limestone as a flux. Charcoal and anthracite have also been used as fuel...
and
steelSteel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
production, mercury production (mostly for batteries), and biomass burning.
Small independent gold mining operation workers are at higher risk of mercury poisoning because of crude processing methods. Such is the danger for the
galamseyA galamsey is a local artisanal gold miner in Ghana, West Africa; such workers are known as orpailleurs in neighboring francophone nations. Galamseys are people who do gold mining independent of mining companies, digging small workings by hand.-Background:Generally the galamseys can dig only to a...
in Ghana and similar workers known as
orpailleurs in neighboring
francophoneThe adjective francophone means French-speaking, typically as primary language, whether referring to individuals, groups, or places. Often, the word is used as a noun to describe a natively French-speaking person....
countries. While there are no official government estimates of the labor force, observers believe 20,000-50,000 work as galamseys in Ghana, a figure that includes many women, who work as porters.
Mercury and many of its chemical compounds, especially
organomercuryOrganomercury refers to the group of organometallic compounds that contain mercury. Typically the Hg-C bond is stable toward air and moisture but sensitive to light. Important organomercury compounds are the methylmercury cation, CH3Hg+; ethylmercury cation, C2H5Hg+; dimethylmercury, 2Hg,...
compounds, can also be readily absorbed through direct contact with bare, or in some cases (such as dimethylmercury) insufficiently protected, skin. Mercury and its compounds are commonly used in chemical laboratories, hospitals, dental clinics, and facilities involved in the production of items such as fluorescent light bulbs, batteries, and explosives.
Mechanism
Mercury is such a highly reactive toxic agent that it is difficult to identify its specific mechanism of damage, and much remains unknown about the mechanism. It damages the
central nervous systemThe central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
,
endocrine systemIn physiology, the endocrine system is a system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body. The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts. It derives from the Greek words "endo"...
,
kidneyThe kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s, and other organs, and adversely affects the mouth, gums, and teeth. Exposure over long periods of time or heavy exposure to mercury vapor can result in brain damage and ultimately death. Mercury and its compounds are particularly toxic to
fetusA fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...
es and infants. Women who have been exposed to mercury in pregnancy have sometimes given birth to children with serious birth defects (see
Minamata disease', sometimes referred to as , is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death...
).
Mercury exposure in young children can have severe neurological consequences, preventing nerve sheaths from forming properly. Mercury inhibits the formation of
myelinMyelin is a dielectric material that forms a layer, the myelin sheath, usually around only the axon of a neuron. It is essential for the proper functioning of the nervous system. Myelin is an outgrowth of a type of glial cell. The production of the myelin sheath is called myelination...
.
There is some evidence that mercury poisoning may predispose to Young's syndrome (men with
bronchiectasisBronchiectasis is a disease state defined by localized, irreversible dilation of part of the bronchial tree caused by destruction of the muscle and elastic tissue. It is classified as an obstructive lung disease, along with emphysema, bronchitis, asthma, and cystic fibrosis...
and low sperm count).
Mercury poisoning's effects partially depend on whether it has been caused by exposure to elemental mercury, inorganic mercury compounds (as salts), or organomercury compounds.
Elemental mercury
QuicksilverMercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
(liquid metallic mercury) is poorly absorbed by ingestion and skin contact. It is hazardous due to its potential to release mercury vapor. Animal data indicate that less than 0.01% of ingested mercury is absorbed through the intact
gastrointestinal tractThe human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
; though it may not be true for individuals suffering from
ileusIleus is a disruption of the normal propulsive ability of the gastrointestinal tract.Ileus is commonly defined simply as bowel obstruction. However, authoritative sources define it as decreased motor activity of the GI tract due to non-mechanical causes...
. Cases of systemic toxicity from accidental swallowing are rare, and attempted suicide via intravenous injection does not appear to result in systemic toxicity. Though not studied quantitatively, the physical properties of liquid elemental mercury limit its absorption through intact skin and in light of its very low absorption rate from the gastrointestinal tract, skin absorption would not be high. Some mercury vapor is absorbed dermally but uptake by this route is only approximately 1% of that by inhalation.
In humans, approximately 80% of inhaled mercury vapor is absorbed via the
respiratory tractIn humans the respiratory tract is the part of the anatomy involved with the process of respiration.The respiratory tract is divided into 3 segments:*Upper respiratory tract: nose and nasal passages, paranasal sinuses, and throat or pharynx...
, where it enters the
circulatory systemThe circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...
and is distributed throughout the body. Chronic exposure by inhalation, even at low concentrations in the range 0.7–42 μg/m
3, has been shown in case control studies to cause effects such as tremors, impaired cognitive skills, and sleep disturbance in workers.
Acute inhalation of high concentrations causes a wide variety of cognitive, personality, sensory, and motor disturbances. The most prominent symptoms include tremors (initially affecting the hands and sometimes spreading to other parts of the body), emotional lability (characterized by irritability, excessive shyness, confidence loss, and nervousness),
insomniaInsomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
,
memory lossMemory loss can be partial or total and it is normal when it comes with aging. Sudden memory loss is usually a result of brain trauma and it may be permanent or temporary. When it is caused by medical conditions such as Alzheimers, the memory loss is gradual and tends to be permanent.Brain trauma...
, neuromuscular changes (weakness, muscle atrophy, muscle twitching), headaches,
polyneuropathyPolyneuropathy is a neurological disorder that occurs when many peripheral nerves throughout the body malfunction simultaneously. It may be acute and appear without warning, or chronic and develop gradually over a longer period of time. Many polyneuropathies have both motor and sensory...
(paresthesia, stocking-glove sensory loss, hyperactive tendon reflexes, slowed sensory and motor nerve conduction velocities), and performance deficits in tests of cognitive function.
Inorganic mercury compounds
Mercury occurs inorganically as salts such as
mercury(II) chlorideMercury chloride or mercuric chloride , is the chemical compound with the formula HgCl2. This white crystalline solid is a laboratory reagent and a molecular compound. It is no longer used for medicinal purposes Mercury(II) chloride or mercuric chloride (formerly corrosive sublimate), is the...
. Mercury salts affect primarily the gastro-intestinal tract and the
kidneyThe kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s, and can cause severe kidney damage; however, as they cannot cross the
blood-brain barrierThe blood–brain barrier is a separation of circulating blood and the brain extracellular fluid in the central nervous system . It occurs along all capillaries and consists of tight junctions around the capillaries that do not exist in normal circulation. Endothelial cells restrict the diffusion...
easily, mercury salts inflict little neurological damage without continuous or heavy exposure. As two
oxidation stateIn chemistry, the oxidation state is an indicator of the degree of oxidation of an atom in a chemical compound. The formal oxidation state is the hypothetical charge that an atom would have if all bonds to atoms of different elements were 100% ionic. Oxidation states are typically represented by...
s of mercury form salts (Hg
+ and Hg
2+), mercury salts occur in both mercury(I) (or mercurous) and mercury(II) (mercuric) forms. Mercury(II) salts are usually more toxic than their mercury(I) counterparts because their
solubilitySolubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...
in water is greater; thus, they are more readily absorbed from the gastrointestinal tract.
Mercuric cyanide
Mercuric cyanide (also known as Mercury (II) cyanide), Hg(CN)
2, is a particularly toxic mercury compound. If ingested, both life-threatening mercury and
cyanide poisoningCyanide poisoning occurs when a living organism is exposed to a compound that produces cyanide ions when dissolved in water. Common poisonous cyanide compounds include hydrogen cyanide gas and the crystalline solids potassium cyanide and sodium cyanide...
can occur. Hg(CN)
2 can enter the body via inhalation,
ingestionIngestion is the consumption of a substance by an organism. In animals, it normally is accomplished by taking in the substance through the mouth into the gastrointestinal tract, such as through eating or drinking...
, or passage through the
skin-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...
. Inhalation of mercuric cyanide
irritatesIrritation or exacerbation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant...
the
throatIn vertebrate anatomy, the throat is the anterior part of the neck, in front of the vertebral column. It consists of the pharynx and larynx...
and air passages. Heating or contact of Hg(CN)
2 with acid or acid mist releases toxic mercury and cyanide vapors that can cause
bronchitisAcute bronchitis is an inflammation of the large bronchi in the lungs that is usually caused by viruses or bacteria and may last several days or weeks. Characteristic symptoms include cough, sputum production, and shortness of breath and wheezing related to the obstruction of the inflamed airways...
with cough and phlegm and/or
lungThe human lungs are the organs of respiration in humans. Humans have two lungs, with the left being divided into two lobes and the right into three lobes. Together, the lungs contain approximately of airways and 300 to 500 million alveoli, having a total surface area of about in...
tissue irritation. Contact with
eyeThe human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
s can cause
burnA burn is an injury to flesh caused by heat, electricity, chemicals, light, radiation, or friction.Burn may also refer to:*Combustion*Burn , type of watercourses so named in Scotland and north-eastern England...
s and brown stains in the eyes, and long-time exposure can affect the
peripheral vision Peripheral vision is a part of vision that occurs outside the very center of gaze. There is a broad set of non-central points in the field of view that is included in the notion of peripheral vision...
. Contact with skin can cause skin
allergyAn Allergy is a hypersensitivity disorder of the immune system. Allergic reactions occur when a person's immune system reacts to normally harmless substances in the environment. A substance that causes a reaction is called an allergen. These reactions are acquired, predictable, and rapid...
, irritation, and gray skin color.
Chronic exposure to trace amounts of the compound can lead to mercury buildup in the body over time; it may take months or even years for the body to eliminate excess mercury. Overexposure to mercuric cyanide can lead to
kidney damageNephrotoxicity is a poisonous effect of some substances, both toxic chemicals and medication, on the kidneys. There are various forms of toxicity. Nephrotoxicity should not be confused with the fact that some medications have a predominantly renal excretion and need their dose adjusted for the...
and/or mercury poisoning, leading to 'shakes' (ex: shaky handwriting),
irritabilityIrritability is an excessive response to stimuli. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli; It is usually used to refer to anger or frustration....
, sore
gumsThe gingiva , or gums, consists of the mucosal tissue that lies over the mandible and maxilla inside the mouth.-General description:...
, increased
salivaSaliva , referred to in various contexts as spit, spittle, drivel, drool, or slobber, is the watery substance produced in the mouths of humans and most other animals. Saliva is a component of oral fluid. In mammals, saliva is produced in and secreted from the three pairs of major salivary glands,...
, metallic taste, loss of
appetiteThe appetite is the desire to eat food, felt as hunger. Appetite exists in all higher life-forms, and serves to regulate adequate energy intake to maintain metabolic needs. It is regulated by a close interplay between the digestive tract, adipose tissue and the brain. Decreased desire to eat is...
,
memoryIn psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing memory....
loss,
personalityPersonality type refers to the psychological classification of different types of individuals. Personality types are sometimes distinguished from personality traits, with the latter embodying a smaller grouping of behavioral tendencies. Types are sometimes said to involve qualitative differences...
changes, and
brain damage"Brain damage" or "brain injury" is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors...
. Exposure to large doses at one time can lead to sudden death.
Mercuric cyanide has not been tested on its ability to cause reproductive damage. Although inorganic mercury compounds (such as Hg(CN)
2) have not been shown to be human
teratogensTeratology is the study of abnormalities of physiological development. It is often thought of as the study of human birth defects, but it is much broader than that, taking in other non-birth developmental stages, including puberty; and other non-human life forms, including plants.- Etymology :The...
, they should be handled with care as they are known to damage developing
embryoAn embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s and decrease
fertilityFertility is the natural capability of producing offsprings. As a measure, "fertility rate" is the number of children born per couple, person or population. Fertility differs from fecundity, which is defined as the potential for reproduction...
in men and women.
According to one study, two people exhibited symptoms of cyanide poisoning within hours after ingesting mercuric cyanide or mercury oxycyanide, Hg(CN)
2•HgO, in
suicideSuicide is the act of intentionally causing one's own death. Suicide is often committed out of despair or attributed to some underlying mental disorder, such as depression, bipolar disorder, schizophrenia, alcoholism, or drug abuse...
attempts. The toxicity of Hg(CN)
2 is commonly assumed to arise almost exclusively from mercury poisoning; however, the patient who ingested mercury oxycyanide died after 5 hours of cyanide poisoning before any mercury poisoning symptoms were observed. The patient who ingested Hg(CN)
2 initially showed symptoms of acute cyanide poisoning, which were brought under control, and later showed signs of mercury poisoning before recovering. It is thought that the degree to which cyanide poisoning occurs is related to whether cyanide ions are released in the
stomachThe stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
, which depends on factors such as the amount ingested, stomach acidity, and volume of stomach contents. Given that Hg(CN)
2 molecules remain undissociated in pure water and in
basicFor the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...
solutions, it makes sense that dissociation would increase with increasing acidity. High stomach acidity thus helps cyanide ions to become more
bioavailableIn pharmacology, bioavailability is a subcategory of absorption and is used to describe the fraction of an administered dose of unchanged drug that reaches the systemic circulation, one of the principal pharmacokinetic properties of drugs. By definition, when a medication is administered...
, increasing the likelihood of cyanide poisoning.
Mercury cyanide was used in two murders in New York in 1898. The perpetrator, Roland B. Molineux, sent poisoned medicines to his victims through the
US mailThe United States Postal Service is an independent agency of the United States government responsible for providing postal service in the United States...
. The first victim, Henry Barnett, died of mercury poisoning twelve days after taking the poison. The second victim, Catherine Adams, died of cyanide poisoning within 30 minutes of taking the poison. As in the suicide cases, the difference between the two cases may be attributed to differences in the acidities of the solutions containing the poison, or to differences in the acidities of the victims' stomachs.
The drug NAP (n-acetyl penicillamine) has been used to treat mercury poisoning with limited success.
Organic mercury compounds
Compounds of mercury tend to be much more toxic than the element itself, and organic compounds of mercury are often extremely toxic and have been implicated in causing
brain"Brain damage" or "brain injury" is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors...
and
liver damageHepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...
. The most dangerous mercury compound,
dimethylmercuryDimethylmercury is an organomercury compound. This colorless liquid is one of the strongest known neurotoxins. It is described as having a slightly sweet smell, although inhaling enough vapor to detect its odor would be hazardous....
, is so toxic that even a few microliters spilled on the skin, or even a latex glove, can cause death.
MethylmercuryMethylmercury is an organometallic cation with the formula . It is a bioaccumulative environmental toxicant.-Structure:...
is the major source of organic mercury for all individuals. It works its way up the
food chainA food web depicts feeding connections in an ecological community. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs...
through
bioaccumulationBioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost...
in the environment, reaching high concentrations among populations of some species. Larger species of fish, such as
tunaTuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...
or
swordfishSwordfish , also known as broadbill in some countries, are large, highly migratory, predatory fish characterized by a long, flat bill. They are a popular sport fish of the billfish category, though elusive. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood...
, are usually of greater concern than smaller species. The U.S.
Food and Drug AdministrationThe Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
(FDA) and the U.S.
Environmental Protection AgencyThe U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
(EPA) advise women of child-bearing age, nursing mothers, and young children to completely avoid
swordfishSwordfish , also known as broadbill in some countries, are large, highly migratory, predatory fish characterized by a long, flat bill. They are a popular sport fish of the billfish category, though elusive. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood...
,
sharkSharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
,
king mackerelThe king mackerel is a migratory species of mackerel of the western Atlantic Ocean and Gulf of Mexico. It is an important species to both the commercial and recreational fishing industries.-Description:...
and
tilefishTilefishes, also known as blanquillo, are mostly small perciform marine fish comprising the family Malacanthidae.They are usually found in sandy areas, especially near coral reefs....
from the Gulf of Mexico, (Golden Tilefish from the Mid- and North-Atlantic present no risk), to limit consumption of
albacore ("white") tunaThe albacore, Thunnus alalunga, is a type of tuna in the family Scombridae. This species is also called albacore fish, albacore tuna, albicore, longfin, albies, pigfish, tombo ahi, binnaga, Pacific albacore, German bonito , longfin tuna, longfin tunny, or even just tuna...
to no more than 6 oz (170.1 g) per week, and of all other fish and shellfish to no more than 12 oz (340.2 g) per week. A 2006 review, conducted by Dr. Dariush Mozaffarian and Dr. Eric B. Rimm, of the risks and benefits of fish consumption found that for adults the benefits of one to two servings of fish per week outweigh the risks, even (except for a few fish species) for women of childbearing age, and that avoidance of fish consumption could result in significant excess
coronary heart diseaseCoronary artery disease is the end result of the accumulation of atheromatous plaques within the walls of the coronary arteries that supply the myocardium with oxygen and nutrients. It is sometimes also called coronary heart disease...
deaths and suboptimal
neural developmentNeural development comprises the processes that generate, shape, and reshape the nervous system, from the earliest stages of embryogenesis to the final years of life. The study of neural development aims to describe the cellular basis of brain development and to address the underlying mechanisms...
in children. (Dr. Rimm has reported in the past that he has received payment or honoraria for presentations about food and diets from both the Culinary Institute of America and the International Chefs Association, among others.)
There is a long latent period between exposure to methylmercury and the appearance of symptoms in adult poisoning cases. The longest recorded latent period is five months after a single exposure, in the Dartmouth case (see History); other latent periods in the range of weeks to months have also been reported. No explanation for this long latent period is known. When the first symptom appears, typically
paresthesiaParesthesia , spelled "paraesthesia" in British English, is a sensation of tingling, burning, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
(a tingling or numbness in the skin), it is followed rapidly by more severe effects, sometimes ending in
comaIn medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
and death. The toxic damage appears to be determined by the peak value of mercury, not the length of the exposure.
EthylmercuryEthylmercury is a cation composed of an ethyl group bound to a mercury centre; its chemical formula is C2H5Hg+...
is a breakdown product of the antibacteriological agent ethylmercurithiosalicylate, which has been used as a topical antiseptic and a vaccine preservative (further discussed under Thiomersal below). Its characteristics have not been studied as extensively as those of methylmercury. It is cleared from the blood much more rapidly, with a half-life of 7 to 10 days, and it is metabolized much more quickly than methylmercury. It is presumed not to have methylmercury's ability to cross the
blood-brain barrierThe blood–brain barrier is a separation of circulating blood and the brain extracellular fluid in the central nervous system . It occurs along all capillaries and consists of tight junctions around the capillaries that do not exist in normal circulation. Endothelial cells restrict the diffusion...
via a transporter, but instead relies on simple diffusion to enter the brain.
Other exposure sources of organic mercury include phenylmercuric acetate and phenylmercuric nitrate. These were used in indoor latex paints for their anti-mildew properties, but were removed in 1990 because of cases of toxicity.
Diagnosis
Diagnosis of elemental or inorganic mercury poisoning involves determining the history of exposure, physical findings, and an elevated body burden of mercury. Although whole-blood mercury concentrations are typically less than 6 μg/L, diets rich in fish can result in blood mercury concentrations higher than 200 μg/L; it is not that useful to measure these levels for suspected cases of elemental or inorganic poisoning because of mercury's short half-life in the blood. If the exposure is chronic, urine levels can be obtained; 24-hour collections are more reliable than spot collections. It is difficult or impossible to interpret urine samples of patients undergoing
chelation therapyChelation therapy is the administration of chelating agents to remove heavy metals from the body. For the most common forms of heavy metal intoxication—those involving lead, arsenic or mercury—the standard of care in the United States dictates the use of dimercaptosuccinic acid...
, as the therapy itself increases mercury levels in the samples.
Diagnosis of organic mercury poisoning differs in that whole-blood or hair analysis is more reliable than urinary mercury levels.
Prevention
Mercury poisoning can be prevented (or minimized) by eliminating or reducing exposure to mercury and mercury compounds. To that end, many governments and private groups have made efforts to regulate heavily the use of mercury, or to issue advisories about its use.
For example, the export from the
European UnionThe European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
of mercury and some mercury compounds has been prohibited since 2010-03-15.
The variability among regulations and advisories is at times confusing for the lay person as well as scientists.
| Country |
Regulating agency |
Regulated activity |
Medium |
Type of mercury compound |
Type of limit |
Limit |
| US |
Occupational Safety and Health AdministrationThe United States Occupational Safety and Health Administration is an agency of the United States Department of Labor. It was created by Congress of the United States under the Occupational Safety and Health Act, signed by President Richard M. Nixon, on December 29, 1970...
|
occupational exposure |
air |
elemental mercury |
Ceiling (not to exceed) |
0.1 mg/m³ |
| US |
Occupational Safety and Health Administration |
occupational exposure |
air |
organic mercury |
Ceiling (not to exceed) |
0.05 mg/m³ |
| US |
Food and Drug Administration |
drinking |
water |
inorganic mercury |
Maximum allowable concentration |
2 ppb In science and engineering, the parts-per notation is a set of pseudo units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement...
(0.002 mg/L) |
| US |
Food and Drug Administration |
eating |
sea food |
methylmercury |
Maximum allowable concentration |
1 ppm In science and engineering, the parts-per notation is a set of pseudo units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they are pure numbers with no associated units of measurement...
(1 mg/L) |
| US |
Environmental Protection AgencyThe U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
|
drinking |
water |
inorganic mercury |
Maximum contaminant level |
2 ppb (0.002 mg/L) |
The United States Environmental Protection Agency (EPA) issued recommendations in 2004 regarding exposure to
mercury in fishFish and shellfish concentrate mercury in their bodies, often in the form of methylmercury, a highly toxic organic compound of mercury. Fish products have been shown to contain varying amounts of heavy metals, particularly mercury and fat-soluble pollutants from water pollution...
and shellfish. The EPA also developed the "Fish Kids" awareness campaign for children and young adults on account of the greater impact of mercury exposure to that population.
Treatment
Identifying and removing the source of the mercury is crucial. Decontamination requires removal of clothes, washing skin with soap and water, and flushing the eyes with saline solution as needed. Inorganic ingestion such as mercuric chloride should be approached as the ingestion of any other serious caustic. Immediate
chelation therapyChelation therapy is the administration of chelating agents to remove heavy metals from the body. For the most common forms of heavy metal intoxication—those involving lead, arsenic or mercury—the standard of care in the United States dictates the use of dimercaptosuccinic acid...
is the
standard of careIn tort law, the standard of care is the degree of prudence and caution required of an individual who is under a duty of care.The requirements of the standard are closely dependent on circumstances. Whether the standard of care has been breached is determined by the trier of fact, and is usually...
for a patient showing symptoms of severe mercury poisoning or the laboratory evidence of a large total mercury load.
Chelation therapyChelation therapy is the administration of chelating agents to remove heavy metals from the body. For the most common forms of heavy metal intoxication—those involving lead, arsenic or mercury—the standard of care in the United States dictates the use of dimercaptosuccinic acid...
for acute inorganic mercury poisoning can be done with DMSA,
2,3-dimercapto-1-propanesulfonic acid2,3-Dimercapto-1-propanesulfonic acid and its sodium salt are chelating agents that form complexes with various heavy metals. They are related to dimercaprol, which is another chelating agent....
(DMPS), D-penicillamine (DPCN), or
dimercaprolDimercaprol or British anti-Lewisite , is a compound developed by British biochemists at Oxford University during World War II. It was developed secretly as an antidote for lewisite, the now-obsolete arsenic-based chemical warfare agent. Today, it is used medically in treatment of arsenic,...
(BAL). Only DMSA is FDA-approved for use in children for treating mercury poisoning. However, several studies found no clear clinical benefit from DMSA treatment for poisoning due to mercury vapor. No chelator for methylmercury or ethylmercury is approved by the FDA; DMSA is the most frequently used for severe methylmercury poisoning, as it is given orally, has fewer side-effects, and has been found to be superior to BAL, DPCN, and DMPS. Alpha-lipoic acid (ALA) has been shown to be protective against acute mercury poisoning in several mammalian species when it is given soon after exposure; correct dosage is required, as inappropriate dosages increase toxicity. Although it has been hypothesized that frequent low dosages of ALA may have potential as a mercury chelator, studies in rats have been contradictory.
GlutathioneGlutathione is a tripeptide that contains an unusual peptide linkage between the amine group of cysteine and the carboxyl group of the glutamate side-chain...
and N-acetylcysteine (NAC) are recommended by some physicians, but have been shown to increase mercury concentrations in the kidneys and the brain. Experimental findings have demonstrated an interaction between
seleniumSelenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
and methylmercury, but epidemiological studies have found little evidence that selenium helps to protect against the adverse effects of methylmercury.
Even if the patient has no symptoms or documented history of mercury exposure, a minority of physicians (predominantly those in
alternative medicineAlternative medicine is any healing practice, "that does not fall within the realm of conventional medicine." It is based on historical or cultural traditions, rather than on scientific evidence....
) use chelation to "rid" the body of mercury, which they believe to cause neurological and other disorders. A common practice is to challenge the patient's body with a chelation agent, collect urine samples, and then use laboratory reports to diagnose the patient with toxic levels of mercury; often no pre-chelation urine sample is collected for comparison. The patient is then advised to undergo further chelation. No scientific data supports the claim that the mercury in vaccines causes autism or its symptoms, and there is no scientific support for chelation therapy as a treatment for autism.
Chelation therapy can be hazardous if administered incorrectly. In August 2005, an incorrect form of EDTA used for chelation therapy resulted in hypocalcemia, causing
cardiac arrestCardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...
that killed a five-year-old autistic boy.
Prognosis
Many of the toxic effects of mercury are partially or wholly reversible, either through specific therapy or through natural elimination of the metal after exposure has been discontinued. However, heavy or prolonged exposure can do irreversible damage, in particular in fetuses, infants, and young children. Young's syndrome is believed to be a long term consequence of early childhood mercury poisoning. Mercuric chloride may cause cancer as it has caused increases in several types of tumors in rats and mice, while methyl mercury has caused kidney tumors in male rats. The EPA has classified mercuric chloride and methyl mercury as possible human carcinogens (ATSDR, EPA)
Detection in biological fluids
Mercury may be measured in blood or urine to confirm a diagnosis of poisoning in hospitalized victims or to assist in the forensic investigation in a case of fatal overdosage. Some analytical techniques are capable of distinguishing organic from inorganic forms of the metal. The concentrations in both fluids tend to reach high levels early after exposure to inorganic forms, while lower but very persistent levels are observed following exposure to elemental or organic mercury. Chelation therapy can cause a transient elevation of urine mercury levels.
History
- The first emperor of unified China, Qin Shi Huang
Qin Shi Huang , personal name Ying Zheng , was king of the Chinese State of Qin from 246 BC to 221 BC during the Warring States Period. He became the first emperor of a unified China in 221 BC...
, it is reported, died of ingesting mercury pills that were intended to give him eternal life.
- The phrase mad as a hatter
"Mad as a hatter" is a colloquial phrase used in conversation to refer to a crazy person. In 18th and 19th century England mercury was used in the production of felt, which was used in the manufacturing of hats common of the time...
is likely a reference to mercury poisoning, as mercury-based compounds were once used in the manufacture of felt hatsFelt is a non-woven cloth that is produced by matting, condensing and pressing woollen fibres. While some types of felt are very soft, some are tough enough to form construction materials. Felt can be of any colour, and made into any shape or size....
in the 18th and 19th century. (The Mad HatterHatta, the Hatter is a fictional character in Lewis Carroll's Alice's Adventures in Wonderland and the story's sequel, Through the Looking-Glass. He is often referred to as the Mad Hatter, though this term was never used by Carroll...
character of Alice in Wonderland was, it is presumed, inspired by an eccentric furniture dealer named Theophilus CarterTheophilus Carter was an eccentric British inventor and furniture dealer most famous for his combination of an alarm clock and a bed, and thought to be an inspiration for the illustration by Sir John Tenniel of Lewis Carroll's characters the Mad Hatter in Alice's Adventures in Wonderland and Hatta...
. Carter was not a victim of mad hatter diseaseMad hatter disease describes the symptoms of mercury poisoning, specifically its effect on the nervous system. These include paraesthesias, vision and hearing impairment, slurred speech, anxiety, hallucinations, irritability, depression, lack of coordination, and tremors. The condition was...
although Lewis Carrol would have been familiar with the phenomenon of dementia that occurred among hatters.)
- In 1810, two British ships, HMS Triumph
HMS Triumph was a 74-gun third rate ship of the line of the Royal Navy, launched on 3 March 1764 at Woolwich.In 1797, she took part in the Battle of Camperdown, and in 1805 Triumph was part of Admiral Calder's fleet at the Battle of Cape Finisterre....
and HMS Phipps, salvaged a large load of elemental mercury from a wrecked Spanish vessel near Cadiz, Spain. The bladders containing the mercury soon ruptured. The element spread about the ships in liquid and vapor forms. The sailors presented with neurologic compromises: tremor, paralysis, and excessive salivation as well as tooth loss, skin problems, and pulmonary complaints. In 1823 William Burnet, MD published a report on the effects of Mercurial vapor. The Triumph’s surgeon, Henry Plowman, had concluded that the ailments had arisen from inhaling the mercurialized atmosphere. His treatment was to order the lower deck gun ports to be opened, when it was safe to do so; sleeping on the orlop was forbidden; and no men slept in the lower deck if they were at all symptomatic. Windsails were set to channel fresh air into the lower decks day and night.
- For years, including the early part of his presidency, Abraham Lincoln
Abraham Lincoln was the 16th President of the United States, serving from March 1861 until his assassination in April 1865. He successfully led his country through a great constitutional, military and moral crisis – the American Civil War – preserving the Union, while ending slavery, and...
took a common medicine of his time called "blue massBlue mass was the name of a medicine prescribed, made, and sold in the United States in the 19th century.-Description:Blue mass was recommended as a remedy for such widely varied complaints as tuberculosis, constipation, toothache, parasitic infestations, and the pains of childbirth...
," which contained significant amounts of mercury.
- On September 5, 1920, silent movie actress Olive Thomas
Olive Thomas was an American silent film actress and model. She is best remembered for her marriage to Jack Pickford and her death.-Early life:...
ingested mercury capsules dissolved in an alcoholic solution at the Hotel Ritz in Paris. There is still controversy over whether it was suicide, or whether she consumed the external preparation by mistake. Her husband, Jack PickfordJack Pickford was a Canadian-born American actor. He was best known for his tabloid lifestyle, marriage to the top starlets of his day, and being of the famous Pickford acting family.-Early life:...
(the brother of Mary PickfordMary Pickford was a Canadian-born motion picture actress, co-founder of the film studio United Artists and one of the original 36 founders of the Academy of Motion Picture Arts and Sciences...
), had syphilisSyphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis...
, and the mercury was used as a treatment of the venereal disease at the time. She died a few days later at the American Hospital in Neuilly.
- An early scientific study of mercury poisoning was in 1923–6 by the German inorganic chemist, Alfred Stock
Alfred Stock was a German inorganic chemist. He did pioneering research on the hydrides of boron and silicon, coordination chemistry, mercury, and mercury poisoning...
, who himself became poisoned, together with his colleagues, by breathing mercury vapor that was being released by his laboratory equipment—diffusion pumpDiffusion pumps use a high speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the exhaust. Presented in 1915 by Wolfgang Gaede and using mercury vapor, they were the first type of high vacuum pumps operating in the regime of free molecular flow,...
s, float valves, and manometers—all of which contained mercury, and also from mercury that had been accidentally spilt and remained in cracks in the linoleumLinoleum is a floor covering made from renewable materials such as solidified linseed oil , pine rosin, ground cork dust, wood flour, and mineral fillers such as calcium carbonate, most commonly on a burlap or canvas backing; pigments are often added to the materials.The finest linoleum floors,...
floor covering. He published a number of papers on mercury poisoning, founded a committee in Berlin to study cases of possible mercury poisoning, and introduced the term micromercurialism.
- The term Hunter-Russell syndrome derives from a study of mercury poisoning among workers in a seed packing factory in Norwich
Norwich is a city in England. It is the regional administrative centre and county town of Norfolk. During the 11th century, Norwich was the largest city in England after London, and one of the most important places in the kingdom...
, England in the late 1930s who breathed methylmercuryMethylmercury is an organometallic cation with the formula . It is a bioaccumulative environmental toxicant.-Structure:...
that was being used as a seed disinfectant and preservative.
- Outbreaks of methylmercury
Methylmercury is an organometallic cation with the formula . It is a bioaccumulative environmental toxicant.-Structure:...
poisoning occurred in several places in Japan during the 1950s due to industrial discharges of mercury into rivers and coastal waters. The best-known instances were in Minamatais a city located in Kumamoto prefecture, Japan. It is on the west coast of Kyūshū. The city was founded on April 1, 1949.As of 2008, the city has an estimated population of 27,856 and the density of 171 persons per km²...
and Niigais a prefecture of Japan located on the island of Honshū on the coast of the Sea of Japan. The capital is the city of Niigata. The name "Niigata" literally means "new lagoon".- History :...
. In Minamata alone, more than 600 people died due to what became known as Minamata disease', sometimes referred to as , is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death...
. More than 21,000 people filed claims with the Japanese government, of which almost 3000 became certified as having the disease. In 22 documented cases, pregnant women who consumed contaminated fish showed mild or no symptoms but gave birth to infants with severe developmental disabilities.
- Widespread mercury poisoning occurred in rural Iraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....
in 1971-1972, when grain treated with a methylmercury-based fungicideFungicides are chemical compounds or biological organisms used to kill or inhibit fungi or fungal spores. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality and profit. Fungicides are used both in agriculture and to fight fungal infections in animals...
that was intended for planting only was used by the rural population to make bread, causing at least 6530 cases of mercury poisoning and at least 459 deaths (see Basra poison grain disasterThe 1971 Iraq poison grain disaster was a mass methylmercury poisoning incident that began in late 1971. Grain treated with a methylmercury fungicide and never intended for human consumption was imported into Iraq as seed grain from Mexico and the United States...
).
- On August 14, 1996, Karen Wetterhahn
Karen Wetterhahn was a well-known professor of chemistry at Dartmouth College, New Hampshire, who specialized in toxic metal exposure. She made national headlines when mercury poisoning claimed her life at the age of 48 due to accidental exposure to the organic mercury compound dimethylmercury...
, a chemistry professor working at Dartmouth CollegeDartmouth College is a private, Ivy League university in Hanover, New Hampshire, United States. The institution comprises a liberal arts college, Dartmouth Medical School, Thayer School of Engineering, and the Tuck School of Business, as well as 19 graduate programs in the arts and sciences...
, spilled a small amount of dimethylmercuryDimethylmercury is an organomercury compound. This colorless liquid is one of the strongest known neurotoxins. It is described as having a slightly sweet smell, although inhaling enough vapor to detect its odor would be hazardous....
on her latex glove. She began experiencing the symptoms of mercury poisoning five months later and, despite aggressive chelation therapyChelation therapy is the administration of chelating agents to remove heavy metals from the body. For the most common forms of heavy metal intoxication—those involving lead, arsenic or mercury—the standard of care in the United States dictates the use of dimercaptosuccinic acid...
, died a few months later from brain malfunctionEncephalopathy means disorder or disease of the brain. In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of global brain dysfunction; this syndrome can be caused by many different illnesses.-Terminology:...
due to mercury intoxication.
- In April 2000, Alan Chmurny attempted to kill a former employee, Marta Bradley, by pouring mercury into the ventilation
Ventilating is the process of "changing" or replacing air in any space to provide high indoor air quality...
system of her car.
- On March 19, 2008, Tony Winnett, 55, inhaled mercury vapors while trying to extract gold from computer parts (by using liquid mercury to separate gold from the rest of the alloy), and died ten days later. His Oklahoma residence became so contaminated that it had to be gutted.
- In December 2008, actor Jeremy Piven
Jeremy Samuel Piven is an American film producer and actor best known for his role as Ari Gold in the television series Entourage for which he has won three Emmy Awards as well as several other nominations for Best Supporting Actor....
was diagnosed with hydrargyria resulting from eating sushi twice a day for twenty years.
- Actress Daphne Zuniga
Daphne Eurydice Zuniga is an American actress known for her roles as Jo Reynolds on the Fox primetime soap Melrose Place, as Victoria Davis on The CW teen drama One Tree Hill and as Princess Vespa in Spaceballs.-Early life:...
diagnosed with mercury poisoning for eating sushi four times a week.
Infantile acrodynia
Infantile acrodynia (also known as "calomel disease", "erythredemic polyneuropathy", and "pink disease") is a type of mercury poisoning in children characterized by pain and pink discoloration of the hands and feet. The word is derived from the
GreekGreek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
, where άκρο means
end (as in: upper
extremityA limb is a jointed, or prehensile , appendage of the human or other animal body....
) and οδυνη means
pain. Also known as pink disease, Swift disease, Feer disease, Selter disease, erythroderma, erythroderma polyneuritis, dermatopolyneuritis, trophodermatoneurose, erythema arthricum epidemicum, vegetativ neurose, and vegetativ encephalit. These terms describe different aspects of the syndrome. Acrodynia was relatively commonplace among children in the first half of the 20th century. At first, the cause of the acrodynia
epidemicIn epidemiology, an epidemic , occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience...
among infants and young children was unknown; however, mercury poisoning, primarily from calomel in teething powders, began to be widely accepted as its cause in the 1950s and 60s. The prevalence of acrodynia decreased greatly after calomel was excluded from most teething powders in 1954.
Acrodynia is difficult to diagnose, "it is most often postulated that the etiology of this syndrome is an idiosyncratic hypersensitivity reaction to mercury because of the lack of correlation with mercury levels, many of the symptoms resemble recognized mercury poisoning."
Medical procedures
Because elemental mercury often passes through the GI tract without being absorbed, it was used medically for various purposes until the dangers of mercury poisoning became known. For example, elemental mercury was used to mechanically clear intestinal obstructions (due to its great weight and fluidity), and it was a key ingredient in various medicines throughout history, such as
blue massBlue mass was the name of a medicine prescribed, made, and sold in the United States in the 19th century.-Description:Blue mass was recommended as a remedy for such widely varied complaints as tuberculosis, constipation, toothache, parasitic infestations, and the pains of childbirth...
. The toxic effects often were either not noticed at all or so subtle or generic that they were attributed to other causes and were not recognized as poisoning caused by mercury. While the usage of mercury in medicine has declined, mercury-containing compounds are still used medically in vaccines and dental amalgam, both of which have been the subject of controversy regarding their potential for mercury poisoning.
Thiomersal
The mercury-based preservative
thiomersalThiomersal , and commonly known in the US as thimerosal, is an organomercury compound. This compound is a well established antiseptic and antifungal agent....
(commonly called
thimerosal in the U.S.) has been added to vaccines since the 1930s to prevent their deterioration. Its use in vaccines has been hypothesized as a cause of
autisticAutism is a disorder of neural development characterized by impaired social interaction and communication, and by restricted and repetitive behavior. These signs all begin before a child is three years old. Autism affects information processing in the brain by altering how nerve cells and their...
behaviors. This hypothesis is controversial, as much evidence suggests that the cause of autism is about 90% genetic. The hypothesis has not been confirmed by reliable studies. However, organizations such as the
American Academy of PediatricsThe American Academy of Pediatrics is the major professional association of pediatricians in the United States. The AAP was founded in 1930 by 35 pediatricians to address pediatric healthcare standards. It currently has 60,000 members in primary care and sub-specialist areas...
have recommended that the use of thiomersal be reduced as a precautionary measure. With the exception of some flu vaccines, it is no longer used as a preservative in routinely recommended childhood vaccines in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
; it is still in limited use as a preservative in multi-dose flu and tetanus vaccines and a few other non-childhood vaccines.
Dental amalgam
Dental amalgamAmalgam is an alloy containing mercury. The term is commonly used for the amalgam employed as material for dental fillings, which consists of mercury , silver , tin , copper , and other trace metals...
, an alloy of about 50 percent elemental mercury, was first introduced in France in the early 19th century. Chosen for its cost-effective durability, this amalgam is a source of very low-level exposure to mercury vapour and generates an enormous amount of controversy. Although the vast majority of patients with amalgam fillings are exposed to levels too low to pose a risk to health, many patients (i.e., those in the upper 99.9 percentile) exhibit urine test results that are comparable to the maximum allowable legal limits for long-term workplace (occupational) safety.
Nonetheless, in the United States the
National Institutes of HealthThe National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...
has stated that amalgam fillings pose no personal health risk, and that replacement by non-amalgam fillings is not indicated. In Scandinavia, amalgam fillings are banned due to concerns over public health and environmental pollution.
In 2002, Maths Berlin, Professor Emeritus of Environmental Medicine and chair of the 1991 World Health Organization Task Group on Environmental Health Criteria for Inorganic Mercury, published an overview and assessment of the scientific literature published between November 1997 and 2002 as part of a special investigation for the Swedish Government on amalgam-related health issues. The report concluded: "With reference to the fact that mercury is a multipotent toxin with effects on several levels of the biochemical dynamics of the cell, amalgam must be considered to be an unsuitable material for dental restoration."
Cosmetics
Some
skin whiteningSkin whitening, skin lightening and skin bleaching refers to the practice of using chemical substances in an attempt to lighten skin tone or provide an even skin complexion by lessening the concentration of melanin...
products contain the toxic chemical mercury(II) chloride as the active ingredient. When applied, the chemical readily absorbs through the skin into the bloodstream. The use of
mercuryMercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
in cosmetics is illegal in the United States. However, cosmetics containing mercury are often illegally imported. Following a certified case of mercury poisoning resulting from the use of an imported skin whitening product, the United States Food and Drug Administration warned against the use of such products. Symptoms of mercury poisoning have resulted from the use of various mercury-containing cosmetic products. The use of skin whitening products is especially popular amongst Asian women. In Hong Kong in 2002, two products were discovered to contain between 9,000 to 60,000 times the recommended dose.
Fluorescent lamps
Fluorescent lampA fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful...
s contain mercury released when bulbs are broken. Mercury in bulbs is typically present as either elemental mercury liquid, vapor, or both, since the liquid evaporates at ambient temperature. When broken indoors, bulbs may emit sufficient mercury vapor to present health concerns, and the U.S. Environmental Protection Agency recommends evacuating and airing out a room for at least 15 minutes after breaking a fluorescent light bulb. Breakage of multiple bulbs presents a greater concern. A 1987 report described a 23-month-old toddler who suffered
anorexiaAnorexia is the decreased sensation of appetite...
, weight loss, irritability, profuse sweating, and peeling and redness of fingers and toes. This case of acrodynia was traced to exposure of mercury from a carton of 8-foot fluorescent light bulbs that had broken in a potting shed adjacent to the main nursery. The glass was cleaned up and discarded, but the child often used the area for play.
Assassination
Mercury has been used at various times to assassinate people. In 2008, Russian lawyer
Karinna MoskalenkoKarinna Akopovna Moskalenko , is Russia’s leading human rights lawyer, defending, amongst others, Mikhail Khodorkovsky, Garry Kasparov and Alexander Litvinenko...
claimed to have been poisoned by mercury left in her car, while in 2010 journalists
Viktor KalashnikovViktor Kalashnikov is a Russian freelance journalist and a former KGB colonel. In the autumn of 2010, he and his wife were treated in hospital in Germany for mercury poisoning in what they said had been an attempt on their lives by Russia's FSB, the successor to the KGB...
and
Marina KalashnikovaMarina Kalashnikova is a Russian historian and freelance journalist. In 2010 she and her ex-KGB agent husband were treated in hospital in Germany for mercury poisoning in what they have said was an attempt on their life by Russia's FSB, the successor to the KGB...
accused Russia's FSB of trying to poison them.
See also
- Diagnosis Mercury: Money, Politics and Poison
Diagnosis Mercury: Money, Politics and Poison is a 2008 book by Jane Hightower. The book explains that mercury is a poison and that the majority of mercury in the environment comes from coal-fired power plants. But the book is mainly concerned with human exposure from the eating of large predatory...
- Erethism
Erethism or erethism mercurialis is a symptom complex of mercury poisoning, presenting with excessive shyness, timidity and social phobia. This was common among hat makers of old England who used mercury to stabilize the wool in a process called felting...
- Got Mercury?
Got Mercury? is a public awareness campaign about mercury levels in seafood. It is sponsored by the Sea Turtle Restoration Project and its parent organization, the Turtle Island Restoration Network...
- Lead poisoning
Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems...
- Mercury vacuum
A mercury vacuum is a vacuum cleaner specifically designed to collect mercury, for instance to clean up spills of the element.-See also:* Mercury poisoning, a disease caused by exposure to the element mercury or its toxic compounds...
- Mercury-containing and Rechargeable Battery Management Act
In the United States, the Mercury-Containing and Rechargeable Battery Management Act was signed into law on May 13, 1996...