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germanium ← arsenic → selenium
P
↑
As
↓
Sb
Appearance
metallic grey
250px
General properties
Name, symbol, number arsenic, As, 33
Pronunciation /ˈɑrsənɪk/ ARS-ə-nik,
also /ɑrˈsɛnɪk/ ar-SEN-ik when attributive
Element category metalloid
Group, period, block 15, 4, p
Standard atomic weight 74.92160(2) g·mol−1
Electron configuration [Ar] 4s2 3d10 4p3
Electrons per shell 2, 8, 18, 5 (Image)
Physical properties
Phase solid
Density (near r.t.) 5.727 g·cm−3
Liquid density at m.p. 5.22 g·cm−3
Sublimation point 887 K, 615 °C, 1139 °F
Triple point 1090 K (817°C), 3628 [1] kPa
Critical point 1673 K, ? MPa
Heat of fusion (grey) 24.44 kJ·mol−1
Heat of vaporization  ? 34.76 kJ·mol−1
Specific heat capacity (25 °C) 24.64 J·mol−1·K−1
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 553 596 646 706 781 874
Atomic properties
Oxidation states 5, 3, 2, 1,[2] -3
(mildly acidic oxide)
Electronegativity 2.18 (Pauling scale)
Ionization energies
(more) 		1st: 947.0 kJ·mol−1
2nd: 1798 kJ·mol−1
3rd: 2735 kJ·mol−1
Atomic radius 119 pm
Covalent radius 119±4 pm
Van der Waals radius 185 pm
Miscellanea
Crystal structure rhombohedral
Magnetic ordering diamagnetic[3]
Electrical resistivity (20 °C) 333 nΩ·m
Thermal conductivity (300 K) 50.2 W·m−1·K−1
Young's modulus 8 GPa
Bulk modulus 22 GPa
Mohs hardness 3.5
Brinell hardness 1440 MPa
CAS registry number 7440-38-2
Most stable isotopes
Main article: Isotopes of arsenic
iso NA half-life DM DE (MeV) DP
73As syn 80.3 d ε - 73Ge
γ 0.05D, 0.01D, e -
74As syn 17.78 d ε - 74Ge
β+ 0.941 74Ge
γ 0.595, 0.634 -
β− 1.35, 0.717 74Se
75As 100% 75As is stable with 42 neutrons

Arsenic (11px /ˈɑrsənɪk/ ARS-ə-nik, also /ɑrˈsɛnɪk/ ar-SEN-ik when attributive) is the chemical element that has the symbol As, atomic number 33 and atomic mass 74.92. Arsenic was first documented by Albertus Magnus in 1250.[4] Arsenic is a notoriously poisonous metalloid. It can exists in various allotropes, although only the grey form is important in a technical sense. Arsenic occurs in many minerals, mainly associated with sulfur and metals. Arsenic and its compounds are mainly used as an alloying agent for lead batteries, but historically it was widely used as pesticides, herbicides, insecticides, but these applications are declining.[5] The occurrence of arsenic in drinking water is problematic in some parts of the world.

Characteristics

Physical characteristics

The most common allotrope of arsenic is grey arsenic. It adopts a layered structure, a ruffled analogue of graphite, consisting of many interlocked six-membered rings. Each atom is bound to three other atoms in the layer and is coordinated by each 3 arsenic atoms in the upper and lower layer. This relatively close packing leads to a high density of 5.73 g/cm3.[6] It is a semiconductor and is soft (mohs scale = 3.5).

Allotropes

File:White phosphrous molecule.jpg
Structure of yellow arsenic As4 and white phosphorus P4

Like phosphorus, arsenic exhibits allotropy, although only the gray allotrope is important under normal conditions. The three most common allotropes are metallic grey, yellow and black arsenic.[7]Yellow arsenic (As4) is soft and waxy, somewhat similar to P4. Both have four atoms arranged in a tetrahedral structure in which each atom is bound to each of the other three atoms by a single bond. This unstable allotrope, being molecular, is the most volatile, least dense, and most toxic. Yellow arsenic is produced by rapid cooling of arsenic vapour, for example with liquid nitrogen. It is rapidly transformed into the grey arsenic by light. The yellow form has a density of 1.97 g/cm3.[6]

Black arsenic is similar in structure to red phosphorus.[6] Three metalloidal forms of arsenic, each with a different structure, are found free in nature (the minerals arsenic sensu stricto and the much rarer arsenolamprite and pararsenolamprite).

Chemical properties

When heated in air, arsenic oxidizes to arsenic trioxide; the fumes from this reaction have an odour resembling garlic. This odour can be detected on striking arsenide minerals such as arsenopyrite with a hammer. Arsenic (and some arsenic compounds) sublimes upon heating at atmospheric pressure, converting directly to a gaseous form without an intervening liquid state. The liquid state appears at 20 atmospheres and above, which explains why the melting point is higher than the boiling point.[6]

Isotopes

Main article: Isotopes of arsenic

Naturally occurring arsenic is composed of one stable isotope, 75As.[8] As of 2003, at least 33 radioisotopes have also been synthesized, ranging in atomic mass from 60 to 92. The most stable of these is 73As with a half-life of 80.3 days. Isotopes that are lighter than the stable 75As tend to decay by β+ decay, and those that are heavier tend to decay by β- decay, with some exceptions.

At least 10 nuclear isomers have been described, ranging in atomic mass from 66 to 84. The most stable of arsenic's isomers is 68mAs with a half-life of 111 seconds.[8]

Occurrence

See also: Arsenide minerals and Arsenate minerals
File:Native arsenic.jpg
A large sample of native arsenic.
Minerals with the formula MAsS and MAs2 (M = Fe, Ni, Co) are the dominant commercial sources of arsenic together with realgar and native As. An illustrative mineral is Arsenopyrite (FeAsS), which is structurally related to iron pyrite.
File:Mineraly.sk - realgar.jpg
Realgar
. Otherwise many minor As-containing minerals are known.

In addition to the inorganic forms mentioned above, arsenic also occurs in various organic forms in the environment.[9]

Other naturally occurring pathways of exposure include volcanic ash, weathering of the arsenic-containing mineral and ores as well as groundwater. It is also found in food, water, soil and air.[10] The most common pathway of exposure for humans is ingestion, and the predominant source of arsenic in our diet is through seafood.[11]

Production

File:World Arsenic Production 2006.svg
Arsenic output in 2006[12]

In 2005, China was the top producer of white arsenic with almost 50% world share, followed by Chile, Peru and Morocco, reports the British Geological Survey and the United States Geological Survey.[12] Most operations in the US and Europe closed for environmental reasons. The arsenic is recovered mainly as a side product from the purification of copper. Arsenic is part of the smelter dust from copper, gold, and lead smelters.[13]

On roasting in air of arsenopyrite, arsenic sublimes as arsenic(III) oxide leaving iron oxides,[9] while roasting without air results in the production of metallic arsenic. Further purification from sulfur and other chalcogens is achieved by sublimation in vacuum or in a hydrogen atmosphere or by distillation from molten lead-arsenic mixture.[14]

Compounds of arsenic

See also Category: Arsenic compounds Arsenic compounds resemble in some respects those of phosphorus, which occupies the same group (column) of the periodic table. Arsenic is less commonly observed in the pentavalent state, however. The most common oxidation states for arsenic are −3 (arsenides, such as alloy-like intermetallic compounds, +3 in arsenates(III) (arsenites) and most organoarsenic compounds). Arsenic also bonds readily to itself as seen in the square As3−4 ions in the mineral skutterudite. In the +3 oxidation state, arsenic is typically pyramindal, owing to the influence of the lone pair of electrons.

Oxides

Arsenic forms colourless, odourless, crystalline oxides As2O3 ("white arsenic") and As2O5 which are hygroscopic and readily soluble in water to form acidic solutions. Arsenic(V) acid is a weak acid. Its salts are called (arsenates, e.g. Paris Green, calcium arsenate, and lead hydrogen arsenate. The latter three have been used as agricultural insecticides and poisons. The protonation steps between the arsenate and arsenic acid are similar to those between phosphate and phosphoric acid. However, arsenite and arsenous acid contain arsenic bonded to three oxygen and not hydrogen atoms, in contrast to phosphite and phosphorous acid (more accurately termed 'phosphonic acid'), which contains a non-acidic P-H bond. Arsenous acid is genuinely tribasic, whereas phosphonic acid is not.

Sulfides and related derivatives

A broad variety of sulfur compounds of arsenic are known. Orpiment (As2S3, As2S3) and realgar (As4S4, As4S4) are somewhat abundant and were formerly used as painting pigments. Other sulfides include As4S3 and and As4S10. Arsenic has a formal oxidation state of +2 in As4S4]], which features As-As bonds so that the total covalency of As is still in fact three.[15]

Halides

The trifloride, trichloride, tribromide, and triiodide of arsenic(III) are well known, whereas only AsF5 is the main pentahalide. Arsenic pentafluoride is stable at room temperature, whereas the pentachloride is only stable below −50 °C.[6]

Alloys

Arsenic is used as group 5 element as components of the III-V semiconductors. Gallium arsenide, indium arsenide and aluminium arsenide are used as semiconductor materials. The valence electron count of GaAs is the same as a pair of Si atoms but the band structure is completely different, which results distinct bulk properties. Other arsenic alloys include cadmium arsenide, gallium arsenide.

Organoarsenic compounds

Main article: organoarsenic chemistry
File:Trimethylarsine-2D.png
Trimethylarsine

A large variety of organoarsenic compounds are known. Many were initially prepared for use in chemical warfare during World War I. Representative compounds have the formulae R3-xAsClx (where R = alkyl and aryl, and x = 0,1,2). Cacodylic acid which is of historic and practical interest, arises from the methylation of arsenic trioxide, a reaction that has no analogy in phosphorus chemistry.

History

The word arsenic was borrowed from the Syriac word ܠܐ ܙܐܦܢܝܐ (al) zarniqa [16] and the Persian word زرنيخ Zarnikh, meaning "yellow orpiment", into Greek as arsenikon (Αρσενικόν). It is also related to the similar Greek word arsenikos (Αρσενικός), meaning "masculine" or "potent". The word was adopted in Latin arsenicum and Old French arsenic, from which the English word arsenic is derived.[16] Arsenic sulfides (orpiment, realgar) and oxides have been known and used since ancient times.[17] Zosimos (circa 300 AD) describes roasting sandarach (realgar) to obtain cloud of arsenic (arsenious oxide) which he then reduces to metallic arsenic.[18] As the symptoms of arsenic poisoning were somewhat ill-defined, it was frequently used for murder until the advent of the Marsh test, a sensitive chemical test for its presence. (Another less sensitive but more general test is the Reinsch test.) Owing to its use by the ruling class to murder one another and its potency and discreetness, arsenic has been called the Poison of Kings and the King of Poisons.[19]

During the Bronze Age, arsenic was often included in bronze, which made the alloy harder (so-called "arsenical bronze"). Albertus Magnus (Albert the Great, 1193–1280) is believed to have been the first to isolate the element in 1250 by heating soap together with arsenic trisulfide.[4] In 1649, Johann Schröder published two ways of preparing arsenic.

File:Arsenic alchemical symbol.svg
Alchemical symbol for arsenic

Cadet's fuming liquid (impure cacodyl), often claimed as the first synthetic organometallic compound, was synthesized in 1760 by Louis Claude Cadet de Gassicourt by the reaction of potassium acetate with arsenic trioxide.[20]

In the Victorian era, "arsenic" ("white arsenic" trioxide) was mixed with vinegar and chalk and eaten by women to improve the complexion of their faces, making their skin paler to show they did not work in the fields. Arsenic was also rubbed into the faces and arms of women to "improve their complexion". The accidental use of arsenic in the adulteration of foodstuffs led to the Bradford sweet poisoning in 1858, which resulted in approximately 20 deaths.[21]

Applications

The largest application of arsenic is for alloying with copper and especially lead. Lead used in automotive batteries is strengthened by the presence of a few percent of arsenic.

Wood preservation

The toxicity of arsenic to insects, bacteria, and fungi led to its use as a wood preservative.[22] In the 1950s a process of treating wood with chromated copper arsenate (also known as CCA or Tanalith) was invented, and for decades this treatment was the most extensive industrial use of arsenic. Due to an increased understanding of arsenic's high level of toxicity, most countries banned the use of CCA in consumer products. The European Union and United States led this ban, beginning in 2004.[23][24]

File:Roxarsone.png
Roxarsone is a widely used and controversial arsenic compound that is used as a nutritional supplement for chickens.

Medical use

During the 18th, 19th, and 20th centuries, a number of arsenic compounds have been used as medicines, including arsphenamine (by Paul Ehrlich) and arsenic trioxide (by Thomas Fowler). Arsphenamine as well as Neosalvarsan was indicated for syphilis and trypanosomiasis, but has been superseded by modern antibiotics. Arsenic trioxide has been used in a variety of ways over the past 500 years, but most commonly in the treatment of cancer. The US Food and Drug Administration in 2000 approved this compound for the treatment of patients with acute promyelocytic leukemia that is resistant to ATRA.[25] It was also used as Fowler's solution in psoriasis.[26] Recently new research has been done in locating tumours using arsenic-74 (a positron emitter). The advantages of using this isotope instead of the previously used iodine-124 is that the signal in the PET scan is clearer as the body tends to transport iodine to the thyroid gland producing a lot of noise.[27]

Pigments

Copper acetoarsenite was used as a green pigment known under many names, including 'Paris Green' and 'Emerald Green'. It caused numerous arsenic poisonings. Scheele's Green, a copper arsenate, was used in the 19th century as a colouring agent in sweets.[28]

Military

After World War I, the United States built up a stockpile of 20000tons of lewisite(ClCH=CHAsCl2), a chemical weapon that is a vesicant (blister agent) and lung irritant. The stockpile was neutralized with bleach and dumped into the Gulf of Mexico after the 1950s.[29] During the Vietnam War the United States used Agent Blue, a mixture of sodium cacodylate) and its acid form, as one of the rainbow herbicides to deprive the Vietnamese of valuable crops.

Other uses

Biological role

File:ArsenobetainePIC.svg
Arsenobetaine

The similarity between arsenic and phosphorus is so great that arsenic will partly substitute for phosphorus in biochemical reactions. However, in subtoxic doses, soluble arsenic compounds act as stimulants, and were once popular in small doses as medicine by people in the mid 18th century.[6]

Some species of bacteria obtain their energy by oxidizing various fuels while reducing arsenate to arsenite. The enzymes involved are known as arsenate reductases (Arr).

In 2008, bacteria were discovered that employ a version of photosynthesis in the absence of oxygen with arsenites as electron donors, producing arsenates (just like ordinary photosynthesis uses water as electron donor, producing molecular oxygen). Researchers conjecture that historically these photosynthesizing organisms produced the arsenates that allowed the arsenate-reducing bacteria to thrive. One strain PHS-1 has been isolated and is related to the γ-Proteobacterium Ectothiorhodospira shaposhnikovii. The mechanism is unknown, but an encoded Arr enzyme may function in reverse to its known homologues.[36]

Arsenic has been linked to epigenetic changes which are heritable changes in gene expression that occur without changes in DNA sequence and include DNA methylation, histone modification and RNA interference. Toxic levels of arsenic cause significant DNA hypermethylation of tumour suppressor genes p16 and p53 thus increasing risk of carcinogenesis. These epigenetic events have been observed in in vitro studies with human kidney cells and in vivo tests with rat liver cells and peripheral blood leukocytes in humans.[37] Inductive coupled plasma mass spectrometry (ICP-MS) is used to detect precise levels of intracellular of arsenic and its other bases involved in epigenetic modification of DNA.[38] Studies investigating arsenic as an epigenetic factor will help in developing precise biomarkers of exposure and susceptibility.

The Chinese brake fern (Pteris vittata), hyperaccumulates arsenic present in the soil into its leaves and has a proposed use in phytoremediation.[39]

Biomethylation of arsenic

Inorganic arsenic and its compounds, upon entering the food chain, are progressively metabolised to less toxic forms of arsenic through a process of methylation. For example, the mold Scopulariopsis brevicaulis produce significant amounts of trimethylarsine if inorganic arsenic is present.[40] The organic compound arsenobetaine is found in some marine foods such as fish and algae, and also in mushrooms in larger concentrations. The average person's intake is about 10–50 µg/day. Values about 1000 µg are not unusual following consumption of fish or mushrooms. But there is little danger in eating fish because this arsenic compound is nearly non-toxic.[41]

Biochemical basis of arsenic toxicity

The high affinity of arsenic(III) oxides for thiols is usually assigned as the cause of the high toxicity. Thiols in the form of cysteine residues, are situated at the active sites of many important enzymes.[5]

Environmental issues

Arsenic in drinking water

Main article: Arsenic contamination of groundwater

Widespread arsenic contamination of groundwater has led to a massive epidemic of arsenic poisoning in Bangladesh[42] and neighbouring countries. Presently 42 major incidents around the world have been reported on groundwater arsenic contamination. It is estimated that approximately 57 million people are drinking groundwater with arsenic concentrations elevated above the World Health Organization's standard of 10 parts per billion. However, a study of cancer rates in Taiwan[43] suggested that significant increases in cancer mortality appear only at levels above 150 parts per billion. The arsenic in the groundwater is of natural origin, and is released from the sediment into the groundwater owing to the anoxic conditions of the subsurface. This groundwater began to be used after local and western NGOs and the Bangladeshi government undertook a massive shallow tube well drinking-water program in the late twentieth century. This program was designed to prevent drinking of bacterially contaminated surface waters, but failed to test for arsenic in the groundwater. Many other countries and districts in South East Asia, such as Vietnam, Cambodia, and China have geological environments conducive to generation of high-arsenic groundwaters. Arsenicosis was reported in Nakhon Si Thammarat, Thailand in 1987, and the dissolved arsenic in the Chao Phraya River is suspected of containing high levels of naturally occurring arsenic, but has not been a public health problem owing to the use of bottled water.[44]

In the United States, arsenic is most commonly found in the ground waters of the southwest.[45] Parts of New England, Michigan, Wisconsin, Minnesota and the Dakotas are also known to have significant[clarification needed] concentrations of arsenic in ground water. Increased levels of skin cancer have been associated with arsenic exposure in Wisconsin, even at levels below the 10 part per billion drinking water standard.[46] According to a recent film funded by the US Superfund, millions of private wells have unknown arsenic levels, and in some areas of the US, over 20% of wells may contain levels that exceed established limits.[47]

Low-level exposure to arsenic at concentrations found commonly in US drinking water compromises the initial immune response to H1N1 or swine flu infection according to NIEHS-supported scientists. The study, conducted in laboratory mice, suggests that people exposed to arsenic in their drinking water may be at increased risk for more serious illness or death in response to infection from the virus.[48]

Epidemiological evidence from Chile shows a dose dependent connection between chronic arsenic exposure and various forms of cancer, particularly when other risk factors, such as cigarette smoking, are present. These effects have been demonstrated to persist below 50 parts per billion.[49]

Analyzing multiple epidemiological studies on inorganic arsenic exposure suggests a small but measurable risk increase for bladder cancer at 10 parts per billion.[50] According to Peter Ravenscroft of the Department of Geography at the University of Cambridge,[51] roughly 80 million people worldwide consume between 10 and 50 parts per billion arsenic in their drinking water. If they all consumed exactly 10 parts per billion arsenic in their drinking water, the previously cited multiple epidemiological study analysis would predict an additional 2,000 cases of bladder cancer alone. This represents a clear underestimate of the overall impact, since it does not include lung or skin cancer, and explicitly underestimates the exposure. Those exposed to levels of arsenic above the current WHO standard should weigh the costs and benefits of arsenic remediation.

Early (1973) evaluations of the removal of dissolved arsenic by drinking water treatment processes demonstrated that arsenic is very effectively removed by co-precipitation with either iron or aluminum oxides. The use of iron as a coagulant, in particular, was found to remove arsenic with efficiencies exceeding 90%.[52][53] Several adsorptive media systems have been approved for point-of-service use in a study funded by the United States Environmental Protection Agency (U.S.EPA) and the National Science Foundation (NSF). A team of European and Indian scientists and engineers have set up six arsenic treatment plants in West Bengal based on in-situ remediation method (SAR Technology). This technology does not use any chemicals and arsenic is left as an insoluble form (+5 state) in the subterranean zone by recharging aerated water into the aquifer and thus developing an oxidation zone to support arsenic oxidizing micro-organisms. This process does not produce any waste stream or sludge and is relatively cheap.[54]

Magnetic separations of arsenic at very low magnetic field gradients have been demonstrated in point-of-use water purification with high-surface-area and monodisperse magnetite (Fe3O4) nanocrystals. Using the high specific surface area of Fe3O4 nanocrystals the mass of waste associated with arsenic removal from water has been dramatically reduced.[55]

Epidemiological studies have suggested a correlation between chronic consumption of drinking water contaminated with arsenic and the incidence of all leading causes of mortality. The literature provides reason to believe arsenic exposure is causative in the pathogenesis of diabetes.

Wood preservation in the US

As of 2002, US-based industries consumed 19,600 metric tons of arsenic. 90% of this was used for treatment of wood with CCA. In 2007, 50% of the 5,280 metric tons of consumption was still used for this purpose.[13][56] In the United States, the use of arsenic in consumer products was discontinued for residential and general consumer construction on December 31, 2003 and alternative chemicals are now used, such as Alkaline Copper Quaternary, borates, copper azole, cyproconazole, and propiconazole.[57]

Although discontinued, this application is also one of the most concern to the general public. The vast majority of older pressure-treated wood was treated with CCA. CCA lumber is still in widespread use in many countries, and was heavily used during the latter half of the 20th century as a structural and outdoor building material. Although the use of CCA lumber was banned in many areas after studies showed that arsenic could leach out of the wood into the surrounding soil (from playground equipment, for instance), a risk is also presented by the burning of older CCA timber. The direct or indirect ingestion of wood ash from burnt CCA lumber has caused fatalities in animals and serious poisonings in humans; the lethal human dose is approximately 20 grams of ash. Scrap CCA lumber from construction and demolition sites may be inadvertently used in commercial and domestic fires. Protocols for safe disposal of CCA lumber do not exist evenly throughout the world; there is also concern in some quarters about the widespread landfill disposal of such timber.

Mapping of industrial releases in the US

One tool that maps releases of arsenic to particular locations in the United States[58] and also provides additional information about such releases is TOXMAP. TOXMAP is a Geographic Information System (GIS) from the Division of Specialized Information Services of the United States National Library of Medicine (NLM) that uses maps of the United States to help users visually explore data from the United States Environmental Protection Agency's (EPA) Toxics Release Inventory and Superfund Basic Research Programs. TOXMAP is a resource funded by the US Federal Government. TOXMAP's chemical and environmental health information is taken from NLM's Toxicology Data Network (TOXNET)[59] and PubMed, and from other authoritative sources.

Safety

Main articles: Arsenic poisoning and Arsenic toxicity
80px

Arsenic and many of its compounds are especially potent poisons. Arsenic disrupts ATP production through several mechanisms. At the level of the citric acid cycle, arsenic inhibits lipoic acid which is a cofactor for pyruvate dehydrogenase; and by competing with phosphate it uncouples oxidative phosphorylation, thus inhibiting energy-linked reduction of NAD+, mitochondrial respiration, and ATP synthesis. Hydrogen peroxide production is also increased, which might form reactive oxygen species and oxidative stress. These metabolic interferences lead to death from multi-system organ failure, probably from necrotic cell death, not apoptosis. A post mortem reveals brick red coloured mucosa, owing to severe haemorrhage. Although arsenic causes toxicity, it can also play a protective role.[60]

Elemental arsenic and arsenic compounds are classified as "toxic" and "dangerous for the environment" in the European Union under directive 67/548/EEC. The International Agency for Research on Cancer (IARC) recognizes arsenic and arsenic compounds as group 1 carcinogens, and the EU lists arsenic trioxide, arsenic pentoxide and arsenate salts as category 1 carcinogens.

Arsenic is known to cause arsenicosis owing to its manifestation in drinking water, “the most common species being arsenate [HAsO42- ; As(V)] and arsenite [H3AsO3 ; As(III)]”. The ability of arsenic to undergo redox conversion between As(III) and As(V) makes its availability in the environment more abundant. According to Croal, Gralnick, Malasarn, and Newman, “[the] understanding [of] what stimulates As(III) oxidation and/or limits As(V) reduction is relevant for bioremediation of contaminated sites (Croal). The study of chemolithoautotrophic As(III) oxidizers and the heterotrophic As(V) reducers can help the understanding of the oxidation and/or reduction of arsenic.[61]

Treatment of chronic arsenic poisoning is easily accomplished. British anti-lewisite (dimercaprol) is prescribed in dosages of 5 mg/kg up to 300 mg each 4 hours for the first day. Then administer the same dosage each 6 hours for the second day. Then prescribe this dosage each 8 hours for eight additional days.[62] However the Agency for Toxic Substances and Disease Registry (ATSDR) states that the long term effects of arsenic exposure cannot be predicted.[11] Blood, urine, hair and nails may be tested for arsenic, however these tests cannot foresee possible health outcomes due to the exposure.[11] Excretion occurs in the urine and long term exposure to arsenic has been linked to bladder and kidney cancer in addition to cancer of the liver, prostate, skin, lungs and nasal cavity.[63]

Occupational exposure

Occupational exposure and arsenic poisoning may occur in persons working in industries involving the use of inorganic arsenic and its compounds, such as wood preservation, glass production, nonferrous metal alloys, and electronic semiconductor manufacturing. Inorganic arsenic is also found in coke oven emissions associated with the smelter industry.[64]

See also

References

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External links

 Periodic table
H   He
Li Be   B C N O F Ne
Na Mg   Al Si P S Cl Ar
K Ca   Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr   Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Rf Db Sg Bh Hs Mt Ds Rg Cn Uut Uuq Uup Uuh Uus Uuo
Alkali metals Alkaline earth metals Lanthanides Actinides Transition metals Other metals Metalloids Other nonmetals Halogens Noble gases
Large version 

af:Arseen ar:زرنيخ az:Arsen bn:আর্সেনিক be:Мыш'як bs:Arsen bg:Арсен ca:Arsènic cs:Arsen co:Arsenicu cy:Arsenig da:Arsen de:Arsen et:Arseen el:Αρσενικό (χημικό στοιχείο) es:Arsénico eo:Arseno eu:Artseniko fa:آرسنیک fr:Arsenic fur:Arsenic ga:Arsanaic gv:Arsnick gl:Arsénico hak:Sṳ̂n xal:Цанхорн ko:비소 hy:Մկնդեղ hi:आर्सेनिक hr:Arsen io:Arseno id:Arsen is:Arsen it:Arsenico he:ארסן jv:Arsenik pam:Arsenic sw:Asenia kv:Еджыд из ht:Asenik la:Arsenicum lv:Arsēns lb:Arsen lt:Arsenas lij:Arscenigo jbo:arseniko hu:Arzén ml:ആർസെനിക് mr:आर्सेनिक ms:Arsenik nl:Arseen ja:ヒ素 no:Arsen nn:Arsen oc:Arsenic uz:Margimush pnb:آرسینک nds:Arsen pl:Arsen pt:Arsênio ro:Arsen qu:Arsiniku ru:Мышьяк sc:Arsènicu stq:Arsen sq:Arseniku scn:Arsenicu simple:Arsenic sk:Arzén sl:Arzen sr:Арсен sh:Arsenik fi:Arseeni sv:Arsenik tl:Arseniko ta:ஆர்சனிக் th:สารหนู tg:Арсен tr:Arsenik uk:Арсен ur:زرنیخ ug:ئارسېن vi:Asen war:Arsenic yo:Arsenic zh-yue:砷

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  1. ↑ Gokcen, N. A (1989). "The As (arsenic) system". Bull. Alloy Phase Diagrams. 10: 11–22. doi:10.1007/BF02882166. 
  2. ↑ Ellis, Bobby D. (2004). "Stabilized Arsenic(I) Iodide: A Ready Source of Arsenic Iodide Fragments and a Useful Reagent for the Generation of Clusters". Inorganic Chemistry. 43: 5981. doi:10.1021/ic049281s.  |first2= missing |last2= in Authors list (help)
  3. ↑ editor-in-chief, David R. Lide. (2000). "Magnetic susceptibility of the elements and inorganic compounds". Handbook of Chemistry and Physics (PDF) (81 ed.). CRC press. ISBN 0849304814. 
  4. ↑ 4.0 4.1 Emsley, John (2001). Nature's Building Blocks: An A-Z Guide to the Elements. Oxford: Oxford University Press. pp. 43,513,529. ISBN 0-19-850341-5. 
  5. ↑ 5.0 5.1 Sabina C. Grund, Kunibert Hanusch, Hans Uwe Wolf "Arsenic and Arsenic Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, VCH-Wiley, 2008, Weinheim.doi:10.1002/14356007.a03_113.pub2
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  7. ↑ Norman, Nicholas C (1998). Chemistry of Arsenic, Antimony and Bismuth. Springer. p. 50. ISBN 9780751403893. 
  8. ↑ 8.0 8.1 Georges, Audi (2003). "The NUBASE Evaluation of Nuclear and Decay Properties". Nuclear Physics A. Atomic Mass Data Center. 729: 3–128. doi:10.1016/j.nuclphysa.2003.11.001. 
  9. ↑ 9.0 9.1 Lua error in package.lua at line 80: module 'Module:Citation/CS1/Suggestions' not found.
  10. ↑ "Case Studies in Environmental Medicine (CSEM) Arsenic Toxicity Exposure Pathways" (PDF). Agency for Toxic Substances & Disease Registry. Retrieved 2010-05-15. 
  11. ↑ 11.0 11.1 11.2 The Agency for Toxic Substances and Disease Registry (2009). Retrieved at http://www.atsdr.cdc.gov/
  12. ↑ 12.0 12.1 Brooks, William E. "Mineral Commodity Summaries 2007: Arsenic" (PDF). United States Geological Survey. Retrieved 2008-11-25. 
  13. ↑ 13.0 13.1 Brooks, William E. "Minerals Yearbook 2007: Arsenic" (PDF). United States Geological Survey. Retrieved 2008-11-08. 
  14. ↑ Whelan, J. M.; Struthers, J. D.; Ditzenberger, J. A. (1960). "Separation of Sulfur, Selenium, and Tellurium from Arsenic". Journal of the Electrochemical Society. 107 (12): 982–985. doi:10.1149/1.2427585. 
  15. ↑ "Arsenic: arsenic(II) sulfide compound data". WebElements.com. Retrieved 2007-12-10. 
  16. ↑ 16.0 16.1 "arsenic". Online Etymology Dictionary. Retrieved 2010-05-15. 
  17. ↑ Bentley, Ronald; Chasteen, Thomas G. (2002). "Arsenic Curiosa and Humanity" (PDF). The Chemical Educator. 7 (2): 51. doi:10.1007/s00897020539a. 
  18. ↑ Holmyard John Eric (2007). Makers of Chemistry. Read Books. ISBN 1406732753. 
  19. ↑ Vahidnia, A.; Van Der Voet, G. B.; De Wolff, F. A. (2007). "Arsenic neurotoxicity - a review". Human & experimental toxicology. 26 (10): 823–32. doi:10.1177/0960327107084539. PMID 18025055. 
  20. ↑ Seyferth, Dietmar (2001). "Cadet's Fuming Arsenical Liquid and the Cacodyl Compounds of Bunsen". Organometallics. 20 (8): 1488–1498. doi:10.1021/om0101947. 
  21. ↑ Turner, Alan (1999). "Viewpoint: the story so far: An overview of developments in UK food regulation and associated advisory committees" (PDF). British Food Journal. 101 (4): 274–283. doi:10.1108/00070709910272141. 
  22. ↑ Rahman FA, Allan DL, Rosen CJ, Sadowsky MJ. "Arsenic availability from chromated copper arsenate (CCA)-treated wood" J Environ Qual. 2004 Jan-Feb;33(1):173-80. pmid = 14964372 }}
  23. ↑ Lichtfouse, Eric (2004). "Electrodialytical Removal of Cu, Cr and As from Threaded Wood". In Lichtfouse, Eric; Schwarzbauer, Jan; Robert, Didier. Environmental Chemistry: Green Chemistry and Pollutants in Ecosystems. Berlin: Springer. ISBN 9783540228608. 
  24. ↑ Mandal, Badal Kumar; Suzuki, K. T. (2002). "Arsenic round the world: a review". Talanta. 58 (1): 201–235. doi:10.1016/S0039-9140(02)00268-0. PMID 18968746. 
  25. ↑ Antman, Karen H. (2001). "The History of Arsenic Trioxide in Cancer Therapy". The oncologist. 6 (Suppl 2): 1–2. doi:10.1634/theoncologist.6-suppl_2-1. PMID 11331433. 
  26. ↑ Huet, P. M.; Guillaume, E.; Cote, J.; Légaré, A.; Lavoie, P.; Viallet, A. (1975). "Noncirrhotic presinusoidal portal hypertension associated with chronic arsenical intoxication". Gastroenterology (Free full text). 68' (5 Pt 1): 1270–1277. PMID 1126603. 
  27. ↑ Jennewein, Marc; Lewis, M. A.; Zhao, D.; Tsyganov, E.; Slavine, N.; He, J.; Watkins, L.; Kodibagkar, V. D.; O'Kelly, S. (2008). "Vascular Imaging of Solid Tumors in Rats with a Radioactive Arsenic-Labeled Antibody that Binds Exposed Phosphatidylserine". Journal of Clinical Cancer (Free full text). 14 (5): 1377–1385. doi:10.1158/1078-0432.CCR-07-1516. PMID 18316558. 
  28. ↑ Timbrell, John (2005). "Butter Yellow and Scheele's Green". The Poison Paradox: Chemicals as Friends and Foes. Oxford University Press. ISBN 9780192804952. 
  29. ↑ "Blister Agents". Code Red - Weapons of Mass Destruction. Retrieved 2010-05-15. 
  30. ↑ Peryea F. J. 1998. Historical use of lead arsenate insecticides, resulting in soil contamination and implications for soil remediation. Proceedings, 16th World Congress of Soil Science, Montpellier, France. 20–26. Aug. Available online: http://soils.tfrec.wsu.edu/leadhistory.htm
  31. ↑ Nachman, Keeve E; Graham, Jay P.; Price, Lance B.; Silbergeld, Ellen K. (2005). "Arsenic: A Roadblock to Potential Animal Waste Management Solutions". Environmental Health Perspective. 113 (9): 1123–1124. doi:10.1289/ehp.7834. 
  32. ↑ "section 5.3, pg. 310" (PDF). Agency for Toxic Substances and Disease Registry. 
  33. ↑ Jones, F. T. (2007). "A Broad View of Arsenic". Poultry Science. 86 (1): 2–14. PMID 17179408. 
  34. ↑ Guruswamy, Sivaraman (1999). "XIV. Ammunition". Engineering Properties and Applications of Lead Alloys. CRC Press. pp. 569–570. ISBN 9780824782474. 
  35. ↑ "Arsenic Supply Demand and the Environment". Pollution technology review 214: Mercury and arsenic wastes: removal, recovery, treatment, and disposal. William Andrew. 1993. p. 68. ISBN 9780815513261. 
  36. ↑ Kulp, T. R; Hoeft, S. E.; Asao, M.; Madigan, M. T.; Hollibaugh, J. T.; Fisher, J. C.; Stolz, J. F.; Culbertson, C. W.; Miller, L. G. (2008). "Arsenic(III) fuels anoxygenic photosynthesis in hot spring biofilms from Mono Lake, California". Science. 321 (5891): 967–970. doi:10.1126/science.1160799. PMID 18703741. Lay summary – Chemistry World, 15 August 2008. 
  37. ↑ Baccarelli, A.; Bollati, V. (2009). "Epigenetics and environmental chemicals". Current opinion in Pediatrics. 21 (2): 243–251. doi:10.1097/MOP.0b013e32832925cc. PMID 19663042. 
  38. ↑ Nicholis, I.; Curis, E.; Deschamps, P.; Bénazeth, S. (2009). "Arsenite medicinal use, metabolism, pharmacokinetics and monitoring in human hair". Biochimie. 91 (10): 12601267. doi:10.1016/j.biochi.2009.06.003. PMID 19527769. 
  39. ↑ Lombi, E.; Zhao, F. J.; Fuhrmann, M.; Ma, L. Q.; McGrath, S. P. (2002). "Arsenic Distribution and Speciation in the Fronds of the Hyperaccumulator Pteris vittata". New Phytologist. 156 (2): 195–203. doi:10.1046/j.1469-8137.2002.00512.x.  edit
  40. ↑ Bentley, Ronald; Chasteen, TG (2002). "Microbial Methylation of Metalloids: Arsenic, Antimony, and Bismuth" (Free full text). Microbiology and Molecular Biology Reviews. 66 (2): 250–271. doi:10.1128/MMBR.66.2.250-271.2002. PMC 120786 Freely accessible. PMID 12040126. 
  41. ↑ Cullen, William R; Reimer, Kenneth J. (1989). "Arsenic speciation in the environment". Chemical Reviews. 89 (4): 713–764. doi:10.1021/cr00094a002. 
  42. ↑ Meharg, Andrew (2005). Venomous Earth - How Arsenic Caused The World's Worst Mass Poisoning. Macmillan Science. ISBN 9781403944993. 
  43. ↑ Lamm, S. H.; Engel, A.; Penn, C. A.; Chen, R.; Feinleib, M. (2006). "Arsenic cancer risk confounder in southwest Taiwan data set". Environ. Health Perspect. 114 (7): 1077–82. doi:10.1289/ehp.8704. PMC 1513326 Freely accessible. PMID 16835062. 
  44. ↑ Kohnhorst, Andrew; Laird, Allan; Prayad, Pokethitiyoke; Suthida, Anyapo (2002). "Groundwater arsenic in central Thailand" (PDF). 28th WEDC Conference Calcutta. Retrieved 2009-01-29. 
  45. ↑ "Arsenic in Drinking Water: 3. Occurrence in U.S. Waters" (PDF). Retrieved 2010-05-15. 
  46. ↑ Knobeloch, L. M.; Zierold, K. M.; Anderson, H. A. (2006). "Association of arsenic-contaminated drinking-water with prevalence of skin cancer in Wisconsin's Fox River Valley". J. Health Popul Nutr (Free full text). 24 (2): 206–13. PMID 17195561. 
  47. ↑ "In Small Doses". 
  48. ↑ Courtney, D; Ely, Kenneth H.; Enelow, Richard I.; Hamilton, Joshua W. (2009). "Low Dose Arsenic Compromises the Immune Response to Influenza A Infection in vivo". Environmental Health Perspectives. 117 (9): 1441–7. doi:10.1289/ehp.0900911. PMC 2737023 Freely accessible. PMID 19750111.  More than one of |magazine= and |journal= specified (help)
  49. ↑ Ferreccio, C.; Sancha, A. M. (2006). "Arsenic exposure and its impact on health in Chile". J Health Popul Nutr (Free full text). 24 (2): 164–75. PMID 17195557. 
  50. ↑ Chu, H. A.; Crawford-Brown, D. J. (2006). "Inorganic arsenic in drinking water and bladder cancer: a meta-analysis for dose-response assessment". Int. J. Environ. Res. Public Health (Free full text). 3 (4): 316–22. doi:10.3390/ijerph2006030039. PMID 17159272. 
  51. ↑ "Arsenic in drinking water seen as threat - USATODAY.com". USA Today. 2007-08-30. Retrieved 2008-01-01. 
  52. ↑ Gulledge, John H.; O'Connor, John T. (1973). "Removal of Arsenic (V) from Water by Adsorption on Aluminum and Ferric Hydroxides". J. American Water Works Assn. 65 (8): 548–552. 
  53. ↑ O'Connor, J. T.; O'Connor, T. L. "Arsenic in Drinking Water: 4. Removal Methods" (PDF). 
  54. ↑ "In situ arsenic treatment". Retrieved 2010-05-13. 
  55. ↑ Yavuz, Cafer T; Mayo, J. T.; Yu, W. W.; Prakash, A.; Falkner, J. C.; Yean, S.; Cong, L.; Shipley, H. J.; Kan, A. (2005). "Low-Field Magnetic Separation of Monodisperse Fe3O4 Nanocrystals". Science. 314 (5801): 964–967. doi:10.1126/science.1131475. PMID 17095696. 
  56. ↑ Reese, Jr, Robert G. "Commodity Summaries 2002: Arsenic" (PDF). United States Geological Survey. Retrieved 2008-11-08. 
  57. ↑ "Chromated Copper Arsenate (CCA)". US Environmental Protection Agency. 
  58. ↑ "TRI Releases Map". Toxmap.nlm.nih.gov. Retrieved 2010-03-23. 
  59. ↑ TOXNET - Databases on toxicology, hazardous chemicals, environmental health, and toxic releases
  60. ↑ Klaassen, Curtis; Watkins, John (2003). Casarett and Doull's Essentials of Toxicology. McGraw-Hill. p. 512. ISBN 978-0071389143. 
  61. ↑ Croal, Laura R.; Gralnick, Jeffrey A.; Malasarn, Davin; Newman, Dianne K. (2004). "The Genetics of Geochemisty". Annual Review of Genetics. 38: 175–206. doi:10.1146/annurev.genet.38.072902.091138. PMID 15568975. 
  62. ↑ The Psychiatric, Psychogenic ans Somatopsychic Disorders Handbook. New Hyde Park, NY: Medical Examination Publishing Co. 1978. pp. 81–82. 
  63. ↑ The Tox Guide for Arsenic (2007). The Agency for Toxic Substances and Disease Registry.Retrieved at http://www.atsdr.cdc.gov/toxguides/toxguide-2.pdf?id=21&tid=3and long
  64. ↑ "OSHA Arsenic". United States Occupational Safety and Health Administration. Retrieved 2007-10-08. 
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