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'''Mercury''' is a [[Chemistry:Chemical element|chemical element]]; it has [[Chemistry:Symbol|symbol]] '''Hg''' and [[Physics:Atomic number|atomic number]] 80. It is also known as '''quicksilver''' and was formerly named '''hydrargyrum''' ({{IPAc-en|h|aɪ|ˈ|d|r|ɑr|dʒ|ər|ə|m}} {{respell|hy|DRAR|jər|əm}}) from the Greek words ''hydor'' (water) and ''argyros'' (silver).<ref name="etym">{{Cite web |title=Definition of hydrargyrum {{!}} Dictionary.com |url=https://www.dictionary.com/browse/hydrargyrum |access-date=2022-12-22 |archive-url=https://web.archive.org/web/20140812203929/http://dictionary.reference.com/browse/hydrargyrum |archive-date=12 August 2014}} ''Random House Webster's Unabridged Dictionary''.</ref> A [[Chemistry:Heavy metals|heavy]], silvery d-block element, mercury is the only metallic element that is known to be liquid at [[Standard temperature and pressure|standard temperature and pressure]]; the only other element that is liquid under these conditions is the [[Chemistry:Halogen|halogen]] [[Chemistry:Bromine|bromine]], though metals such as [[Chemistry:Caesium|caesium]],<!--Fr is not completely certain--> [[Chemistry:Gallium|gallium]], and [[Chemistry:Rubidium|rubidium]] melt just above [[Physics:Room temperature|room temperature]].

Mercury occurs in deposits throughout the world mostly as [[Chemistry:Cinnabar|cinnabar]] (mercuric sulfide). The red pigment [[Chemistry:Vermilion|vermilion]] is obtained by grinding natural cinnabar or synthetic mercuric sulfide. Exposure to mercury and mercury-containing organic compounds is toxic to the [[Biology:Nervous system|nervous system]], [[Biology:Immune system|immune system]] and kidneys of humans and other animals; [[Medicine:Mercury poisoning|mercury poisoning]] can result from exposure to water-soluble forms of mercury (such as mercuric chloride or [[Chemistry:Methylmercury|methylmercury]]) either directly or through mechanisms of biomagnification.

Mercury is used in [[Physics:Thermometer|thermometer]]s, [[Engineering:Barometer|barometer]]s, manometers, [[Engineering:Sphygmomanometer|sphygmomanometer]]s, float valves, [[Chemistry:Mercury switch|mercury switch]]es, [[Chemistry:Mercury relay|mercury relay]]s, [[Physics:Fluorescent lamp|fluorescent lamp]]s and other devices, although concerns about the element's toxicity have led to the phasing out of such mercury-containing instruments.<ref>{{cite web|url=http://www.epa.gov/mercury/|title=What is EPA doing about mercury air emissions?|publisher=United States Environmental Protection Agency (EPA)|access-date=1 May 2007|url-status=live|archive-url=https://web.archive.org/web/20070208013531/http://www.epa.gov/mercury/|archive-date=8 February 2007}}</ref> It remains in use in scientific research applications and in [[Chemistry:Amalgam (dentistry)|amalgam]] for [[Medicine:Dental restoration|dental restoration]] in some locales. It is also used in fluorescent lighting. Electricity passed through mercury vapor in a fluorescent lamp produces short-wave ultraviolet light, which then causes the phosphor in the tube to fluoresce, making visible light.

{{toclimit|3}}

==Properties==

===Physical properties===
[[File:Pound-coin-floating-in-mercury.jpg|thumb|left|An old<ref name="BBCnewpound">{{cite news|title=New 12-sided pound coin to enter circulation in March|url=https://www.bbc.co.uk/news/uk-38480180|access-date=2 January 2017|work=BBC News|date=1 January 2017}}</ref> pound coin (density ~7.6&nbsp;g/cm<sup>3</sup>) floats on mercury due to the combination of the buoyant force and surface tension.]]
Mercury is a heavy, silvery-white metal that is liquid at room temperature. Compared to other metals, it is a poor conductor of heat, but a fair conductor of electricity.<ref name="CRC">{{cite web|last=Hammond |first=C. R. |url=http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/elements.pdf |title=The Elements |archive-url=https://web.archive.org/web/20080626181434/http://www-d0.fnal.gov/hardware/cal/lvps_info/engineering/elements.pdf |archive-date=26 June 2008}} in {{RubberBible86th}}</ref>

It has a [[Physics:Freezing point|freezing point]] of −38.83&nbsp;°C and a [[Physics:Boiling point|boiling point]] of 356.73&nbsp;°C,<ref name="Norrby">{{cite journal |author=Norrby, L.J. |title=Why is mercury liquid? Or, why do relativistic effects not get into chemistry textbooks?| journal=Journal of Chemical Education |volume=68 |issue=2 |page=110 |date=1991 |doi=10.1021/ed068p110 |s2cid=96003717 |bibcode=1991JChEd..68..110N}}</ref><ref>{{cite web| url=http://antoine.frostburg.edu/chem/senese/101/periodic/faq/why-is-mercury-liquid.shtml| title=Why is mercury a liquid at STP?| access-date=1 May 2007| publisher=General Chemistry Online at Frostburg State University| author=Senese, F| archive-url=https://web.archive.org/web/20070404210838/http://antoine.frostburg.edu/chem/senese/101/periodic/faq/why-is-mercury-liquid.shtml| archive-date=4 April 2007| url-status=live}}</ref><ref>{{RubberBible86th|pages=4.125–4.126}}</ref> both the lowest of any stable metal, although preliminary experiments on [[Chemistry:Copernicium|copernicium]] and [[Chemistry:Flerovium|flerovium]] have indicated that they have even lower boiling points.<ref>{{Cite web |title=Dynamic Periodic Table|url=http://www.ptable.com/#Property/State|access-date=22 November 2016|url-status=live |website=www.ptable.com |archive-url=https://web.archive.org/web/20161120061736/http://www.ptable.com/#Property/State|archive-date=20 November 2016}}</ref> This effect is due to [[Chemistry:Lanthanide contraction|lanthanide contraction]] and [[Chemistry:Relativistic quantum chemistry|relativistic contraction]] reducing the radius of the outermost electrons, and thus weakening the metallic bonding in mercury.<ref name="Norrby"/> Upon freezing, the volume of mercury decreases by 3.59% and its density changes from 13.69&nbsp;g/cm<sup>3</sup> when liquid to 14.184&nbsp;g/cm<sup>3</sup> when solid. The coefficient of volume expansion is 181.59 × 10<sup>−6</sup> at 0&nbsp;°C, 181.71 × 10<sup>−6</sup> at 20&nbsp;°C and 182.50 × 10<sup>−6</sup> at 100&nbsp;°C (per&nbsp;°C). Solid mercury is malleable and ductile and can be cut with a knife.<ref>{{cite book|author=Simons, E. N. |title=Guide to Uncommon Metals|date=1968|publisher=Frederick Muller|page=111}}</ref>

Table of thermal and physical properties of liquid mercury:<ref>{{Cite book |last=Holman |first=Jack P. |title=Heat Transfer |publisher=cGraw-Hill Companies, Inc. |year=2002 |isbn=978-0-07-240655-9 |edition=9th |location=New York, NY |pages=600–606 |language=en}}</ref><ref>{{Cite book |last=Incropera |first=Frank P. |title=Fundamentals of Heat and Mass Transfer |publisher=John Wiley and Sons, Inc. |year=2007 |isbn=978-0-471-45728-2 |edition=6th |location=Hoboken, NJ |pages=941–950 |language=en |url=https://books.google.com/books?id=_P9QAAAAMAAJ}}</ref>
{|class="wikitable mw-collapsible mw-collapsed"
|Temperature (°C)
|Density (kg/m^3)
|Specific heat (kJ/kg K)
|Kinematic viscosity (m^2/s)
|Conductivity (W/m K)
|Thermal diffusivity (m^2/s)
|Prandtl Number
|Bulk modulus (K^-1)
|-
|0
|13628.22
|0.1403
|1.24E-07
|8.2
|4.30E-06
|0.0288
|0.000181
|-
|20
|13579.04
|0.1394
|1.14E-07
|8.69
|4.61E-06
|0.0249
|0.000181
|-
|50
|13505.84
|0.1386
|1.04E-07
|9.4
|5.02E-06
|0.0207
|0.000181
|-
|100
|13384.58
|0.1373
|9.28E-08
|10.51
|5.72E-06
|0.0162
|0.000181
|-
|150
|13264.28
|0.1365
|8.53E-08
|11.49
|6.35E-06
|0.0134
|0.000181
|-
|200
|13144.94
|0.157
|8.02E-08
|12.34
|6.91E-06
|0.0116
|0.000181
|-
|250
|13025.6
|0.1357
|7.65E-08
|13.07
|7.41E-06
|0.0103
|0.000183
|-
|315.5
|12847
|0.134
|6.73E-08
|14.02
|8.15E-06
|0.0083
|0.000186
|}

===Chemical properties===
Mercury does not react with most acids, such as dilute [[Chemistry:Sulfuric acid|sulfuric acid]], although [[Chemistry:Oxidizing acid|oxidizing acid]]s such as concentrated sulfuric acid and [[Chemistry:Nitric acid|nitric acid]] or [[Chemistry:Aqua regia|aqua regia]] dissolve it to give sulfate, [[Chemistry:Mercury(II) nitrate|nitrate]], and [[Chemistry:Mercury(II) chloride|chloride]]. Like silver, mercury reacts with atmospheric [[Chemistry:Hydrogen sulfide|hydrogen sulfide]]. Mercury reacts with solid sulfur flakes, which are used in mercury spill kits to absorb mercury (spill kits also use [[Physics:Activated carbon|activated carbon]] and powdered zinc).<ref name="Greenwood" />

====Amalgams====
[[File:Mercury discharge tube.jpg|thumb|left|Mercury-discharge spectral calibration lamp]]
Mercury dissolves many metals such as [[Chemistry:Gold|gold]] and [[Chemistry:Silver|silver]] to form [[Chemistry:Amalgam|amalgams]]. [[Chemistry:Iron|Iron]] is an exception, and iron flasks have traditionally been used to transport the material.<ref>{{Cite web |last=Swackhamer |first=Barry |date=26 November 2011 |title=Mercury Storage Vault |url=https://www.hmdb.org/m.asp?m=49858 |access-date=11 December 2023 |website=The Historic Marker Database}}</ref> Several other first row transition metals with the exception of [[Chemistry:Manganese|manganese]], [[Chemistry:Copper|copper]] and [[Chemistry:Zinc|zinc]] are also resistant in forming amalgams. Other elements that do not readily form amalgams with mercury include [[Chemistry:Platinum|platinum]].<ref>{{cite book |author=Gmelin, Leopold |title=Hand book of chemistry |url=https://books.google.com/books?id=1AI5AAAAMAAJ&pg=PA128 |access-date=30 December 2012|date=1852|publisher=Cavendish Society |pages=103 (Na), 110 (W), 122 (Zn), 128 (Fe), 247 (Au), 338 (Pt)|url-status=live|archive-url=https://web.archive.org/web/20130509033751/http://books.google.com/books?id=1AI5AAAAMAAJ&pg=PA128|archive-date=9 May 2013}}</ref><ref>{{cite book |last=Soratur|first=S. H.|title=Essentials of Dental Materials |url=https://books.google.com/books?id=-U5ztAEACAAJ|date=2002|publisher=Jaypee Brothers Publishers |isbn=978-81-7179-989-3|page=14}}</ref> [[Chemistry:Sodium amalgam|Sodium amalgam]] is a common reducing agent in [[Chemistry:Organic synthesis|organic synthesis]], and is also used in high-pressure sodium lamps.

Mercury readily combines with [[Chemistry:Aluminium|aluminium]] to form a [[Chemistry:Aluminium amalgam|mercury-aluminium amalgam]] when the two pure metals come into contact. Since the amalgam destroys the [[Chemistry:Aluminium oxide|aluminium oxide]] layer which protects metallic aluminium from oxidizing in-depth (as in iron [[Chemistry:Rust|rust]]ing), even small amounts of mercury can seriously corrode aluminium. For this reason, mercury is not allowed aboard an aircraft under most circumstances because of the risk of it forming an amalgam with exposed aluminium parts in the aircraft.<ref name="CorrAl">{{cite book |author=Vargel, C. |author2=Jacques, M. |author3=Schmidt, M. P.| title=Corrosion of Aluminium| date=2004| isbn=978-0-08-044495-6 |publisher=Elsevier |url=https://books.google.com/books?id=NAABS5KrVDYC&pg=PA158 |page=158}}</ref>

[[Physics:Liquid metal embrittlement#Mercury embrittlement|Mercury embrittlement]] is the most common type of liquid metal embrittlement, as mercury is a natural component of some [[Earth:Petroleum reservoir|hydrocarbon reservoirs]] and will come into contact with petroleum processing equipment under normal conditions.<ref>{{cite conference|title=Mercury Liquid Metal Embrittlement Of Alloys For Oil And Gas Production And Processing|url=https://onepetro.org/NACECORR/proceedings-abstract/CORR10/All-CORR10/NACE-10294/126967|first1=Raymundo|last1=Case|first2=Dale R.|last2=McIntyre|date=14 March 2010}}</ref>

===Isotopes===
{{Main|Physics:Isotopes of mercury}}
There are seven stable [[Physics:Isotope|isotope]]s of mercury, with {{chem|202|Hg}} being the most abundant (29.86%). The longest-lived radioisotopes are {{chem|194|Hg}} with a [[Physics:Half-life|half-life]] of 444 years, and {{chem|203|Hg}} with a half-life of 46.612 days. Most of the remaining radioisotopes have half-lives that are less than a day. {{chem|206|Hg}} occurs naturally in tiny traces as an intermediate decay product of {{chem|238|U}}. {{chem|199|Hg}} and {{chem|201|Hg}} are the most often studied [[Physics:Nuclear magnetic resonance|NMR]]-active nuclei, having spins of {{frac|2}} and {{frac|3|2}} respectively.<ref name="CRC" />

==Etymology==
[[File:Mercury symbol (fixed width).svg|thumb|upright=0.55|The symbol for [[Astronomy:Mercury (planet)|the planet Mercury]] (☿) has been used since ancient times to represent the element]]
"Hg" is the modern [[Chemistry:Chemical symbol|chemical symbol]] for mercury. It is an abbreviation of {{lang|la|hydrargyrum}}, a [[Social:Romanization of Greek|romanized]] form of the [[Social:Ancient Greek|ancient Greek]] name for mercury, {{lang|grc|ὑδράργυρος}} ({{transliteration|grc|hydrargyros}}). {{transliteration|grc|Hydrargyros}} is a Greek compound word meaning "water-silver", from {{lang|grc|ὑδρ}}- ({{transliteration|grc|hydr}}-), the root of {{lang|grc|ὕδωρ}} ({{transliteration|grc|hydor}}) "water", and {{lang|grc|ἄργυρος}} ({{transliteration|grc|argyros}}) "silver".<ref name="etym" /> Like the English name quicksilver ("living-silver"), this name was due to mercury's liquid and shiny properties.<ref>{{cite book|url=http://www.websters1913.com/words/Quicksilver|title=Webster's Revised Unabridged Dictionary
|location   = Springfield, Mass.
|publisher  = G. & C. Merriam
|year       = 1913
|accessdate = 27 December 2023
|oclc       = 800618302}}</ref>

The modern English name "mercury" comes from the planet [[Astronomy:Mercury (planet)|Mercury]]. In medieval [[Philosophy:Alchemy|alchemy]], the seven known metals—quicksilver, [[Chemistry:Gold|gold]], [[Chemistry:Silver|silver]], [[Chemistry:Copper|copper]], [[Chemistry:Iron|iron]], [[Chemistry:Lead|lead]], and [[Chemistry:Tin|tin]]—were associated with the seven planets. Quicksilver was associated with the fastest planet, which had been named after the Roman god [[Religion:Mercury (mythology)|Mercury]], who was associated with speed and mobility. The astrological symbol for the planet became one of the [[Unsolved:Alchemical symbol|alchemical symbol]]s for the metal, and "Mercury" became an alternative name for the metal. Mercury is the only metal for which the alchemical planetary name survives, as it was decided it was preferable to "quicksilver" as a chemical name.<ref name="Stillman" /><ref>Maurice Crosland (2004) ''Historical Studies in the Language of Chemistry''</ref>

==History==
Mercury was found in Egyptian tombs that date from 1500 BC;<ref>{{cite web|title=Mercury and the environment — Basic facts|publisher=Environment Canada, Federal Government of Canada|date=2004|url=http://www.ec.gc.ca/mercure-mercury/default.asp?lang=En&n=9A4397AD-1|access-date=27 March 2008|url-status=live|archive-url=https://web.archive.org/web/20110916172302/http://www.ec.gc.ca/mercure-mercury/default.asp?lang=En&n=9A4397AD-1|archive-date=16 September 2011}}</ref> [[Chemistry:Cinnabar|cinnabar]], the most common natural source of mercury, has been in use since the Neolithic Age.<ref>{{cite journal |last1=Martín Gil |first1=J. |last2=Martín Gil |first2=F. J. |last3=Delibes de Castro |first3=G. |last4=Zapatero Magdaleno |first4=P. |last5=Sarabia Herrero |first5=F. J. |year=1995 |title=The first known use of vermillion |journal=Experientia |volume=51 |issue=8 |pages=759–761 |doi=10.1007/BF01922425 |issn=0014-4754 |pmid=7649232 |s2cid=21900879}}</ref>

In {{wipe|China}} and [[Place:Tibet|Tibet]], mercury use was thought to prolong life, heal fractures, and maintain generally good health, although it is now known that exposure to mercury vapor leads to serious adverse health effects.<ref>{{cite web|title=Mercury — Element of the ancients |publisher=Center for Environmental Health Sciences, [[Organization:Dartmouth College|Dartmouth College]] |url=http://www.dartmouth.edu/~toxmetal/mercury/history.html |access-date=9 April 2012|url-status=live|archive-url=https://web.archive.org/web/20121202092915/http://www.dartmouth.edu/~toxmetal/mercury/history.html|archive-date=2 December 2012}}</ref> The first emperor of a unified China, Qín Shǐ Huáng Dì—allegedly buried in a tomb that contained rivers of flowing mercury on a model of the land he ruled, representative of the rivers of China—was reportedly killed by drinking a mercury and powdered [[Chemistry:Jade|jade]] mixture formulated by Qin alchemists intended as an elixir of immortality.<ref>{{cite web|title=Qin Shihuang|publisher=Ministry of Culture, People's Republic of China|date=2003 |url=http://www.chinaculture.org/gb/en_aboutchina/2003-09/24/content_22854.htm|access-date=27 March 2008|archive-url=https://web.archive.org/web/20080704151150/http://www.chinaculture.org/gb/en_aboutchina/2003-09/24/content_22854.htm|archive-date=4 July 2008}}</ref><ref name="wright">{{cite book|title=The History of China|date=2001|author=Wright, David Curtis |publisher=Greenwood Publishing Group|isbn=978-0-313-30940-3 |url=https://archive.org/details/historyofchina00wrig/page/49 |page=49|url-access=registration}}</ref> Khumarawayh ibn Ahmad ibn Tulun, the second Tulunid ruler of Egypt (r. 884–896), known for his extravagance and profligacy, reportedly built a basin filled with mercury, on which he would lie on top of air-filled cushions and be rocked to sleep.<ref>{{cite encyclopedia |title=Khumārawaih |first=Moritz |last=Sobernheim |encyclopedia=E.J. Brill's first encyclopaedia of Islam, 1913–1936, Volume IV: 'Itk–Kwaṭṭa |editor-first=Martijn Theodoor |editor-last=Houtsma |publisher=BRILL |location=Leiden |year=1987 |isbn=978-90-04-08265-6 |url=https://books.google.com/books?id=7CP7fYghBFQC&pg=PA973 |page=973 |url-status=live |archive-date=3 June 2016 |archive-url= https://web.archive.org/web/20160603004305/https://books.google.com/books?id=7CP7fYghBFQC&pg=PA973#v=onepage&q&f=false}}</ref>

In November 2014 "large quantities" of mercury were discovered in a chamber 60 feet below the 1800-year-old pyramid known as the "Temple of the Feathered Serpent," "the third largest pyramid of [[Astronomy:Teotihuacan|Teotihuacan]]," Mexico along with "jade statues, jaguar remains, a box filled with carved shells and rubber balls".<ref name="Yuhas">{{Cite news |last=Yuhas |first=Alan |title=Liquid mercury found under Mexican pyramid could lead to king's tomb |url=https://www.theguardian.com/world/2015/apr/24/liquid-mercury-mexican-pyramid-teotihuacan |date=24 April 2015 |newspaper=The Guardian |language=en-GB |issn=0261-3077 |access-date=22 November 2016 |url-status=live |archive-url=https://web.archive.org/web/20161201200540/https://www.theguardian.com/world/2015/apr/24/liquid-mercury-mexican-pyramid-teotihuacan |archive-date=1 December 2016}}</ref>

[[Biography:Aristotle|Aristotle]] recounts that Daedalus made a wooden statue of Venus move by pouring quicksilver in its interior.<ref>{{cite book |last=Hicks |first=R. D. |year=1907 |title=Aristotle De Anima |chapter=Chapter 3 |place=Cambridge |publisher=Cambridge University Press |url=https://archive.org/details/aristotledeanima005947mbp/page/n7/mode/2up}} [https://archive.org/stream/aristotledeanima005947mbp/aristotledeanima005947mbp_djvu.txt Text]</ref> In [[Religion:Greek mythology|Greek mythology]] Daedalus gave the appearance of voice in his statues using quicksilver. The {{wipe|Ancient Greece}} used [[Chemistry:Cinnabar|cinnabar]] (mercury sulfide) in ointments; the ancient Egyptians and the Romans used it in cosmetics. In Lamanai, once a major city of the Maya civilization, a pool of mercury was found under a marker in a Mesoamerican ballcourt.<ref>{{cite journal |last=Pendergast |first=David M. |title=Ancient maya mercury |journal=Science |volume=217 |issue=4559 |pages=533–535 |date=6 August 1982 |bibcode=1982Sci...217..533P |doi=10.1126/science.217.4559.533 |pmid=17820542 |s2cid=39473822}}</ref><ref>{{cite web |title=Lamanai |url=http://www.guidetobelize.info/en/maya/belize-mayan-lamanai-guide.shtml |access-date=17 June 2011 |url-status=live |archive-url=https://web.archive.org/web/20110611124757/http://www.guidetobelize.info/en/maya/belize-mayan-lamanai-guide.shtml |archive-date=11 June 2011}}</ref> By 500 BC mercury was used to make [[Chemistry:Amalgam|amalgams]] (Medieval Latin ''amalgama'', "alloy of mercury") with other metals.<ref>{{cite book |url=https://books.google.com/books?id=DIWEi5Hg93gC&pg=PA120 |page=120|title=Jewelrymaking through history |author=Hesse, R W |publisher=Greenwood Publishing Group|date=2007|isbn=978-0-313-33507-5}}</ref>

[[Philosophy:Alchemy|Alchemists]] thought of mercury as the First Matter from which all metals were formed. They believed that different metals could be produced by varying the quality and quantity of [[Chemistry:Sulfur|sulfur]] contained within the mercury. The purest of these was gold, and mercury was called for in attempts at the [[Chemistry:Chrysopoeia|transmutation]] of base (or impure) metals into gold, which was the goal of many alchemists.<ref name="Stillman">{{cite book|title = Story of Alchemy and Early Chemistry|author = Stillman, J. M.|publisher = Kessinger Publishing|date = 2003|isbn = 978-0-7661-3230-6|pages = 7–9|oclc = 233637688}}</ref>

The mines in Almadén (Spain), [[Earth:Monte Amiata|Monte Amiata]] (Italy), and Idrija (now Slovenia) dominated mercury production from the opening of the mine in Almadén 2500 years ago, until new deposits were found at the end of the 19th century.<ref name="MercHz">{{cite book|title =Mercury hazards to living organisms|author= Eisler, R.| publisher = CRC Press|date = 2006|isbn = 978-0-8493-9212-2|url = https://books.google.com/books?id=gqc8wUvsI8cC}}</ref>

==Occurrence==
Mercury is an extremely rare element in Earth's [[Earth:Crust (geology)|crust]], having an average crustal abundance by mass of only 0.08 parts per million (ppm).<ref>{{cite book |url=https://books.google.com/books?id=GerdDmwMTLkC&pg=PA265 |page=265|title=Geomicrobiology|author=Ehrlich, H. L. |author2=Newman, D. K.|publisher=CRC Press| date=2008|isbn=978-0-8493-7906-2}}</ref> Because it does not blend [[Chemistry:Geochemistry|geochemically]] with those elements that constitute the majority of the crustal mass, mercury ores can be extraordinarily concentrated considering the element's abundance in ordinary rock. The richest mercury ores contain up to 2.5% mercury by mass, and even the leanest concentrated deposits are at least 0.1% mercury (12,000 times average crustal abundance). It is found either as a [[Chemistry:Native metal|native metal]] (rare) or in [[Chemistry:Cinnabar|cinnabar]], metacinnabar, [[Chemistry:Sphalerite|sphalerite]], [[Chemistry:Corderoite|corderoite]], [[Chemistry:Livingstonite|livingstonite]] and other [[Earth:Mineral|mineral]]s, with cinnabar (HgS) being the most common ore.<ref>{{cite journal|title=Mercury from mineral deposits and potential environmental impact |journal=Environmental Geology |volume=43|issue=3|pages=326–338 |author=Rytuba, James J|year=2003 |doi=10.1007/s00254-002-0629-5 |s2cid=127179672}}</ref><ref name="metacinnabar">{{Cite web |url=https://www.mindat.org/min-2670.html |title=Metacinnabar |website=Mindat.org |access-date=2023-11-16}}</ref> Mercury ores often occur in hot springs or other [[Earth:Volcano|volcanic]] regions.<ref>{{cite web|access-date=7 July 2009|title=Mercury Recycling in the United States in 2000 |publisher=USGS |url-status=live |url=http://pubs.usgs.gov/circ/c1196u/Circ_1196_U.pdf|archive-url=https://web.archive.org/web/20090326135650/http://pubs.usgs.gov/circ/c1196u/Circ_1196_U.pdf|archive-date=26 March 2009}}</ref>

Beginning in 1558, with the invention of the [[Chemistry:Patio process|patio process]] to extract silver from ore using mercury, mercury became an essential resource in the economy of Spain and its American colonies. Mercury was used to extract silver from the lucrative mines in New Spain and Peru. Initially, the Spanish Crown's mines in Almadén in Southern Spain supplied all the mercury for the colonies.<ref>{{cite book |author=Burkholder, M.|author2=Johnson, L.|name-list-style=amp|title=Colonial Latin America|publisher=Oxford University Press|date= 2008 |pages=157–159|isbn=978-0-19-504542-0}}</ref> Mercury deposits were discovered in the New World, and more than 100,000 tons of mercury were mined from the region of Huancavelica, Peru, over the course of three centuries following the discovery of deposits there in 1563. The patio process and later [[Chemistry:Pan amalgamation|pan amalgamation]] process continued to create great demand for mercury to treat silver ores until the late 19th century.<ref>{{cite book|url=https://books.google.com/books?id=a4hPCX2XWDIC&pg=PA33|page=33|title=Domestic Architecture and Power |author=Jamieson, R W|publisher=Springer|date=2000|isbn=978-0-306-46176-7}}</ref>

[[File:Mercury-27128.jpg|thumb|Native mercury with cinnabar, Socrates mine, Sonoma County, California. Cinnabar sometimes alters to native mercury in the oxidized zone of mercury deposits.]]
Former mines in Italy, the United States and Mexico, which once produced a large proportion of the world supply, have now been completely mined out or, in the case of Slovenia (Idrija) and Spain (Almadén), shut down due to the fall of the price of mercury. Nevada's McDermitt Mine, the last mercury mine in the United States, closed in 1992. The price of mercury has been highly volatile over the years and in 2006 was $650 per 76-pound (34.46&nbsp;kg) [[Physics:Flask (unit)|flask]].<ref name="brooks_usgs">{{cite web |url=http://minerals.usgs.gov/minerals/pubs/commodity/mercury/mercumcs07.pdf|title=Mercury|author=Brooks, W. E.|date=2007|publisher=U.S. Geological Survey|access-date=30 May 2008|url-status=live|archive-url=https://web.archive.org/web/20080527203059/http://minerals.usgs.gov/minerals/pubs/commodity/mercury/mercumcs07.pdf|archive-date=27 May 2008}}</ref>

Mercury is extracted by heating cinnabar in a current of air and condensing the vapor. The equation for this extraction is:
:HgS + O<sub>2</sub> → Hg + SO<sub>2</sub>

[[File:HgProductionPrice.png|thumb|Evolution of mercury price (U.S.) and production (worldwide)]]
In 2020, China was the top producer of mercury, providing 88% of the world output (2200 out of 2500 tonnes), followed by Tajikistan (178 t), Russia (50 t) and Mexico (32 t).<ref name="Anon. t636">{{cite web | title=World Mineral Production | url=https://nora.nerc.ac.uk/id/eprint/534464/1/WMP_2016_2020.pdf | pages=48 | access-date=22 Nov 2023}}</ref>

Because of the high toxicity of mercury, both the mining of cinnabar and refining for mercury are hazardous and historic causes of mercury poisoning.<ref>{{cite web |url=http://act.credoaction.com/campaign/thanks_mercury/?rc=fb_share1 |title=Thank President Obama and Administrator Jackson for protecting us from toxic mercury |archive-url=https://web.archive.org/web/20120501171523/http://act.credoaction.com/campaign/thanks_mercury/?rc=fb_share1 |archive-date=1 May 2012 |website=Act.credoaction.com |date=21 December 2011 |access-date=30 December 2012}}</ref> In China, prison labor was used by a private mining company as recently as the 1950s to develop new cinnabar mines. Thousands of prisoners were used by the Luo Xi mining company to establish new tunnels.<ref name="GREEN" /> Worker health in functioning mines is at high risk.

A newspaper claimed that an unidentified [[Social:European Union|European Union]] directive calling for energy-efficient lightbulbs to be made mandatory by 2012 encouraged China to re-open cinnabar mines to obtain the mercury required for CFL bulb manufacture. Environmental dangers have been a concern, particularly in the southern cities of Foshan and Guangzhou, and in Guizhou province in the southwest.<ref name="GREEN">{{cite news|author=Sheridan, M.|title='Green' Lightbulbs Poison Workers: hundreds of factory staff are being made ill by mercury used in bulbs destined for the West|date=3 May 2009 |url=http://www.timesonline.co.uk/tol/news/world/asia/article6211261.ece|publisher=The Sunday Times (of London, UK) |archive-url=https://web.archive.org/web/20090517122911/http://www.timesonline.co.uk/tol/news/world/asia/article6211261.ece |archive-date=17 May 2009|url-status=live}}</ref>

Abandoned mercury mine processing sites often contain very hazardous waste piles of roasted cinnabar calcines. Water run-off from such sites is a recognized source of ecological damage. Former mercury mines may be suited for constructive re-use; for example, in 1976 Santa Clara County, California purchased the historic Almaden Quicksilver Mine and created a county park on the site, after conducting extensive safety and environmental analysis of the property.<ref>{{cite book |author=Boulland M |date=2006 |title=New Almaden |url=https://books.google.com/books?id=C6N03Lww1YsC&pg=PA8 |page=8|publisher=Arcadia Publishing|isbn=978-0-7385-3131-1}}</ref>

==Chemistry==
All known mercury compounds exhibit one of two positive oxidation states: I and II.  Experiments have failed to unequivocally demonstrate any higher oxidation states: both the claimed 1976 electrosynthesis of an unstable Hg(III) species and 2007 cryogenic isolation of HgF<sub>4</sub> have disputed interpretations and remain difficult (if not impossible) to reproduce.<ref>For a general overview, see {{Cite journal|last1=Riedel |first1=S. |last2=Kaupp |first2=M. |doi=10.1016/j.ccr.2008.07.014 |title=The Highest Oxidation States of the Transition Metal Elements |journal=Coordination Chemistry Reviews |volume=253 |issue=5–6 |pages=606–624 |year=2009}}<p>The claimed 1976 synthesis is {{cite journal |last1=Deming |first1=Richard L. |last2=Allred |first2=A. L. |last3=Dahl |first3=Alan R. |last4=Herlinger |first4=Albert W. |last5=Kestner |first5=Mark O. |title=Tripositive mercury. Low temperature electrochemical oxidation of 1,4,8,11-tetraazacyclotetradecanemercury(II) tetrafluoroborate |journal=Journal of the American Chemical Society |date=July 1976 |volume=98 |issue=14 |pages=4132–4137 |doi=10.1021/ja00430a020 |postscript=; }} but note that Reidel & Kaupp cite more recent work arguing that the [[Chemistry:Cyclam|cyclam]] ligand is instead oxidized.</p><p>The claimed 2007 isolation is {{cite journal |author=Xuefang Wang |first2=Lester |last2=Andrews |first3=Sebastian |last3=Riedel |first4=Martin |last4=Kaupp |title=Mercury Is a Transition Metal: The First Experimental Evidence for HgF<sub>4</sub> |journal=Angew. Chem. Int. Ed. |date=2007 |volume=46 |issue=44 |pages=8371–8375 |doi=10.1002/anie.200703710 |pmid=17899620 |postscript=,}} but the spectral identifications are disputed in {{Cite journal |title=Mercury-fluorine interactions: a matrix isolation investigation of Hg⋯F<sub>2</sub>, HgF<sub>2</sub> and HgF<sub>4</sub> in argon matrices |last1=Rooms |first1=J. F. |last2=Wilson |first2=A. V. |last3=Harvey |first3=I. |last4=Bridgeman |first4=A. J. |last5=Young |first5=N. A. |journal=Phys Chem Chem Phys |year=2008 |volume=10 |issue=31 |pages=4594–605 |doi=10.1039/b805608k |pmid=18665309 |bibcode=2008PCCP...10.4594R}}</p></ref>

===Compounds of mercury(I)===
Unlike its lighter neighbors, cadmium and zinc, mercury usually forms simple stable compounds with metal-metal bonds. Most mercury(I) compounds are diamagnetic and feature the dimeric cation, Hg{{su|b=2|p=2+}}. Stable derivatives include the chloride and nitrate. Treatment of Hg(I) compounds complexation with strong ligands such as sulfide, cyanide, etc. and induces disproportionation to {{chem|Hg|2+}} and elemental mercury.<ref name="henderson">{{cite book| title=Main group chemistry| author=Henderson, W.| location=Great Britain| publisher=Royal Society of Chemistry| date=2000| isbn=978-0-85404-617-1| url=https://books.google.com/books?id=twdXz1jfVOsC&pg=PA162| page=162| url-status=live| archive-url=https://web.archive.org/web/20160513101559/https://books.google.com/books?id=twdXz1jfVOsC&pg=PA162| archive-date=13 May 2016}}</ref> [[Chemistry:Mercury(I) chloride|Mercury(I) chloride]], a colorless solid also known as [[Chemistry:Calomel|calomel]], is really the compound with the formula Hg<sub>2</sub>Cl<sub>2</sub>, with the connectivity Cl-Hg-Hg-Cl. It reacts with chlorine to give mercuric chloride, which resists further oxidation. [[Chemistry:Mercury(I) hydride|Mercury(I) hydride]], a colorless gas, has the formula HgH, containing no Hg-Hg bond; however, the gas has only ever been observed as isolated molecules.<ref>{{cite journal|doi=10.1063/1.1676373|title=Hyperfine Interaction, Chemical Bonding, and Isotope Effect in ZnH, CdH, and HgH Molecules|year=1971|last1=Knight|first1=Lon B.|journal=The Journal of Chemical Physics|volume=55|issue=5|pages=2061–2070|bibcode=1971JChPh..55.2061K}}</ref>

Indicative of its tendency to bond to itself, mercury forms [[Physics:Mercury polycations|mercury polycations]], which consist of linear chains of mercury centers, capped with a positive charge. One example is {{chem|Hg|3|2+|(AsF|6|-|)}}{{su|b=2}}.<ref>{{Cite journal| last1=Brown| first1=I. D.| last2=Gillespie| first2=R. J.| last3=Morgan| first3=K. R.| last4=Tun| first4=Z.| last5=Ummat| first5=P. K.| title=Preparation and crystal structure of mercury hexafluoroniobate ({{chem|Hg|3|NbF|6}}) and mercury hexafluorotantalate ({{chem|Hg|3|TaF|6}}): mercury layer compounds| journal=Inorganic Chemistry| volume=23| issue=26| pages=4506–4508| year=1984| doi=10.1021/ic00194a020}}</ref>

===Compounds of mercury(II)===
Mercury(II) is the most common oxidation state and is the main one in nature as well. All four mercuric halides are known and have been demonstrated to form linear [[Physics:Coordination geometry|coordination geometry]], despite mercury's tendency to form [[Physics:Tetrahedral molecular geometry|tetrahedral molecular geometry]] with other ligands. This behavior is similar to the [[Chemistry:Silver|Ag<sup>+</sup>]] ion. The best known mercury halide is [[Chemistry:Mercury(II) chloride|mercury(II) chloride]], an easily sublimating white solid.<ref name=EB1911>{{cite EB1911 |wstitle=Corrosive Sublimate |volume=7 |page=197}}</ref>

[[Chemistry:Mercury(II) oxide|Mercury(II) oxide]], the main [[Chemistry:Oxide|oxide]] of mercury, arises when the metal is exposed to air for long periods at elevated temperatures. It reverts to the elements upon heating near 400&nbsp;°C, as was demonstrated by [[Biography:Joseph Priestley|Joseph Priestley]] in an early synthesis of pure [[Chemistry:Oxygen|oxygen]].<ref name="Greenwood">{{Greenwood&Earnshaw2nd}}</ref> Hydroxides of mercury are poorly characterized, as attempted isolation studies of [[Chemistry:Mercury(II) hydroxide|mercury(II) hydroxide]] have yielded mercury oxide instead.<ref>{{cite journal |doi=10.1002/hlca.19580410411|title=Monomolekular gelöstes Quecksilberhydroxyd und seine Basizität|year=1958|last1=Anderegg|first1=G.|last2=Schwarzenbach|first2=G.|last3=Padmoyo|first3=M.|last4=Borg|first4=Ö. F.|journal=Helvetica Chimica Acta|volume=41|issue=4|pages=988–996}}</ref>

Being a soft metal, mercury forms very stable derivatives with the heavier chalcogens. Preeminent is [[Chemistry:Mercury(II) sulfide|mercury(II) sulfide]], HgS, which occurs in nature as the ore [[Chemistry:Cinnabar|cinnabar]] and is the brilliant pigment [[Chemistry:Vermilion|vermilion]]. Like ZnS, HgS crystallizes in two [[Physics:Polymorphism (materials science)|forms]], the reddish cubic form and the black zinc blende form.<ref name="CRC" /> The latter sometimes occurs naturally as metacinnabar.<ref name="metacinnabar"/> Mercury(II) selenide (HgSe) and mercury(II) telluride (HgTe) are also known, these as well as various derivatives, e.g. [[Physics:Mercury cadmium telluride|mercury cadmium telluride]] and [[Physics:Mercury zinc telluride|mercury zinc telluride]] being semiconductors useful as [[Physics:Infrared detector|infrared detector]] materials.<ref>{{cite book |url=https://books.google.com/books?id=4b3WLgomvd0C&pg=PA507 |page=507|title=Infrared detectors |author=Rogalski, A|publisher=CRC Press|date=2000|isbn=978-90-5699-203-3}}</ref>

Mercury(II) salts form a variety of complex derivatives with [[Chemistry:Ammonia|ammonia]]. These include Millon's base (Hg<sub>2</sub>N<sup>+</sup>), the one-dimensional polymer (salts of {{chem|HgNH|2|+}}){{su|b=n}}), and "fusible white precipitate" or [Hg(NH<sub>3</sub>)<sub>2</sub>]Cl<sub>2</sub>. Known as Nessler's reagent, [[Chemistry:Potassium tetraiodomercurate(II)|potassium tetraiodomercurate(II)]] ({{chem|HgI|4|2-}}) is still occasionally used to test for ammonia owing to its tendency to form the deeply colored iodide salt of Millon's base.<ref>{{VogelQualitative5th|page=319}}
</ref>

[[Chemistry:Mercury(II) fulminate|Mercury fulminate]] is a detonator widely used in explosives.<ref name="CRC" />

===Organomercury compounds===
Organic mercury [[Chemistry:Chemical compound|compounds]] are historically important but are of little industrial value in the western world. Mercury(II) salts are a rare example of simple metal complexes that react directly with aromatic rings. Organomercury compounds are always divalent and usually two-coordinate and linear geometry. Unlike organocadmium and organozinc compounds, organomercury compounds do not react with water. They usually have the formula HgR<sub>2</sub>, which are often volatile, or HgRX, which are often solids, where R is [[Chemistry:Aryl|aryl]] or [[Chemistry:Alkyl|alkyl]] and X is usually halide or acetate. [[Chemistry:Methylmercury|Methylmercury]], a generic term for compounds with the formula CH<sub>3</sub>HgX, is a dangerous family of compounds that are often found in polluted water.<ref name="methylHg">{{cite book |url=https://books.google.com/books?id=BPvWJbBMd7wC |title=Toxicological effects of methylmercury |author1=Committee on the Toxicological Effects of Methylmercury |author2=Board on Environmental Studies and Toxicology |author3=Commission on Life Sciences |author4=National Research Council |publisher=National Academies Press |date=2000 |isbn=978-0-309-07140-6}}</ref> They arise by a process known as biomethylation.

==Applications==
[[File:Maximum thermometer close up 2.JPG|thumb|right|The bulb of a [[Chemistry:Mercury-in-glass thermometer|mercury-in-glass thermometer]]]]
Mercury is used primarily for the manufacture of industrial chemicals or for electrical and electronic applications. It is used in some [[Engineering:Liquid-in-glass thermometer|liquid-in-glass thermometer]]s, especially those used to measure high temperatures. A still increasing amount is used as gaseous mercury in fluorescent lamps, while most of the other applications are slowly being phased out due to health and safety regulations. In some applications, mercury is replaced with less toxic but considerably more expensive [[Chemistry:Galinstan|Galinstan]] [[Chemistry:Alloy|alloy]].<ref>{{cite journal |doi=10.1007/s00216-005-0069-7 |date=November 2005 |author=Surmann, P |author2=Zeyat, H |title=Voltammetric analysis using a self-renewable non-mercury electrode |volume=383 |issue=6 |pages=1009–13 |pmid=16228199 |journal=Analytical and Bioanalytical Chemistry |s2cid=22732411}}</ref>

===Medicine===
{{see also|Amalgam (dentistry)}}[[File:Amalgam.jpg|thumb|right|Amalgam filling]]
====Historical and folk====
Mercury and its compounds have been used in medicine, although they are much less common today than they once were, now that the toxic effects of mercury and its compounds are more widely understood. An example of the early therapeutic application of mercury of was published in 1787 by James Lind.<ref>{{Cite journal|last=Lind|first=J|date=1787|title=An Account of the Efficacy of Mercury in the Cure of Inflammatory Diseases, and the Dysentery|journal=The London Medical Journal|volume=8|issue=Pt 1|pages=43–56|issn=0952-4177|pmc=5545546 |pmid=29139904}}</ref>

The first edition of the Merck's Manual (1899) featured many then-medically relevant mercuric compounds, such as [[Chemistry:Mercuric amidochloride|mercury-ammonium chloride]], [[Chemistry:Mercury(I) iodide|yellow mercury proto-iodide]], [[Chemistry:Mercury(I) chloride|calomel]], and [[Chemistry:Mercury(II) chloride|mercuric chloride]], among others.<ref>{{cite book|title=Merck's Manual 1899 |edition=1st |url=http://www.gutenberg.org/ebooks/41697|access-date=16 June 2013|url-status=live|archive-url=https://web.archive.org/web/20130824150245/http://www.gutenberg.org/ebooks/41697|archive-date=24 August 2013}}</ref>

Mercury in the form of one of its common ores, cinnabar, is used in various traditional medicines, especially in [[Medicine:Traditional Chinese medicine|traditional Chinese medicine]]. Review of its safety has found that cinnabar can lead to significant mercury intoxication when heated, consumed in overdose, or taken long term, and can have adverse effects at therapeutic doses, though effects from therapeutic doses are typically reversible. Although this form of mercury appears to be less toxic than other forms, its use in traditional Chinese medicine has not yet been justified, as the therapeutic basis for the use of cinnabar is not clear.<ref>{{cite journal |author=Liu J |author2= Shi JZ |author3=Yu LM |author4=Goyer RA |author5=Waalkes MP |title=Mercury in traditional medicines: is cinnabar toxicologically similar to common mercurials? |journal=Exp. Biol. Med. (Maywood) |volume=233 |issue=7 |pages=810–7 |date=2008 |pmid=18445765 |pmc=2755212 |doi=10.3181/0712-MR-336 }}</ref>

[[Chemistry:Mercury(I) chloride|Mercury(I) chloride]] (also known as calomel or mercurous chloride) has been used in [[Medicine:Traditional medicine|traditional medicine]] as a [[Chemistry:Diuretic|diuretic]], topical [[Chemistry:Disinfectant|disinfectant]], and [[Chemistry:Laxative|laxative]]. [[Chemistry:Mercury(II) chloride|Mercury(II) chloride]] (also known as mercuric chloride or corrosive sublimate) was once used to treat [[Medicine:Syphilis|syphilis]] (along with other mercury compounds), although it is so toxic that sometimes the symptoms of its toxicity were confused with those of the syphilis it was believed to treat.<ref>{{cite news |vauthors=Pimple KD, Pedroni JA, Berdon V |date=9 July 2002 |url=http://www.indiana.edu/~poynter/sas/lb/syphilis.html |title=Syphilis in history |publisher=Poynter Center for the Study of Ethics and American Institutions at Indiana University-Bloomington |access-date=17 April 2005 |archive-url=https://web.archive.org/web/20050216215916/http://www.indiana.edu/~poynter/sas/lb/syphilis.html |archive-date=16 February 2005 }}</ref> It is also used as a disinfectant. [[Chemistry:Blue mass|Blue mass]], a pill or syrup in which mercury is the main ingredient, was prescribed throughout the 19th century for numerous conditions including constipation, depression, child-bearing and toothaches.<ref name="lincoln">{{cite news |title= Did Mercury in "Little Blue Pills" Make Abraham Lincoln Erratic? |author= Mayell, H. |url= http://news.nationalgeographic.com/news/2001/07/0717_lincoln.html |work= [[Organization:National Geographic Society|National Geographic News]] |date= 17 July 2007 |access-date= 15 June 2008 |url-status=dead |archive-url= https://web.archive.org/web/20080522125650/http://news.nationalgeographic.com/news/2001/07/0717_lincoln.html |archive-date= 22 May 2008}}</ref> In the early 20th century, mercury was administered to children yearly as a laxative and dewormer, and it was used in teething powders for infants. The mercury-containing organohalide [[Chemistry:Merbromin|merbromin]] (sometimes sold as Mercurochrome) is still widely used but has been banned in some countries, such as the U.S.<ref>{{cite web |url=http://www.straightdope.com/columns/read/2518/what-happened-to-mercurochrome |access-date=7 July 2009 |title=What happened to Mercurochrome? |date=23 July 2004 |url-status=live |archive-url=https://web.archive.org/web/20090411060622/http://www.straightdope.com/columns/read/2518/what-happened-to-mercurochrome |archive-date=11 April 2009}}</ref>

====Contemporary====
Mercury is an ingredient in [[Chemistry:Amalgam (dentistry)|dental amalgams]].<ref>{{cite web |title=Dental Amalgam Fillings |url=https://www.fda.gov/medical-devices/dental-devices/dental-amalgam-fillings |date=2020-09-29 |publisher=U.S. Food and Drug Administration (FDA) |location=Silver Spring, MD}}</ref>

[[Chemistry:Thiomersal|Thiomersal]] (called ''Thimerosal'' in the United States) is an [[Chemistry:Organic compound|organic compound]] used as a [[Chemistry:Preservative|preservative]] in [[Biology:Vaccine|vaccine]]s, although this use is in decline.<ref name="FDA thimerosal">{{cite web |url=https://www.fda.gov/Cber/vaccine/thimerosal.htm |title=Thimerosal in Vaccines |publisher=[[Organization:Food and Drug Administration|Food and Drug Administration]] / Center for Biologics Evaluation and Research |date=6 September 2007 |access-date=1 October 2007 |archive-url=https://web.archive.org/web/20070929105040/https://www.fda.gov/Cber/vaccine/thimerosal.htm |archive-date=29 September 2007}}</ref> Although it was [[Chemistry:Thiomersal controversy|widely speculated]] that this mercury-based preservative could cause or trigger [[Medicine:Autism|autism]] in children, no evidence supports any such link.<ref>{{cite journal |journal=Pediatrics |date=2004 |volume=114 |title=Thimerosal-containing vaccines and autistic spectrum disorder: a critical review of published original data |vauthors=Parker SK, Schwartz B, Todd J, Pickering LK |doi=10.1542/peds.2004-0434 |pmid=15342856|issue=3 |pages=793–804 |citeseerx=10.1.1.327.363 |s2cid=1752023}}<br/>Erratum: {{cite journal |pmid=15630018 |doi=10.1542/peds.2004-2402 |volume=115 |title=Thimerosal-containing vaccines and autistic spectrum disorder: a critical review of published original data |date=January 2005 |journal=Pediatrics |page=200 |vauthors=Parker SK, Todd J, Schwartz B, Pickering LK| issue=1 |s2cid=26700143}}</ref> Nevertheless, thiomersal has been removed from, or reduced to trace amounts in all U.S. vaccines recommended for children 6 years of age and under, with the exception of the inactivated influenza vaccine.<ref name="FDA thimerosal"/> [[Chemistry:Merbromin|Merbromin]] (Mercurochrome), another mercury compound, is a topical antiseptic used for minor cuts and scrapes in some countries. Today, the use of mercury in medicine has greatly declined in all respects, especially in developed countries.<ref>{{Cite web |date=30 April 2009 |title=Quantitative and Qualitative Analysis of Mercury Compounds in the List |url=https://www.fda.gov/RegulatoryInformation/LawsEnforcedbyFDA/SignificantAmendmentstotheFDCAct/FDAMA/ucm100219.htm |website=Federal Food, Drug, and Cosmetic Act (FD&C Act) |publisher=U.S. Food and Drug Administration}}</ref>

Mercury is still used in some [[Chemistry:Mercurial diuretic|diuretics]], although substitutes such as [[Chemistry:Thiazide|thiazides]] now exist for most therapeutic uses.<ref name="Chlorothiazide p.222">{{cite journal|vauthors=Beyer KH|date=September 1993|title=Chlorothiazide. How the thiazides evolved as antihypertensive therapy|journal=Hypertension|volume=22|issue=3|pages=388–91|doi=10.1161/01.hyp.22.3.388|pmid=8349332|doi-access=free}}</ref>  In 2003, mercury compounds were found in some [[Medicine:Over-the-counter drug|over-the-counter drug]]s, including topical antiseptics, stimulant laxatives, diaper-rash [[Medicine:Ointment|ointment]], eye drops, and [[Medicine:Nasal spray|nasal spray]]s. The [[Organization:Food and Drug Administration|FDA]] has "inadequate data to establish general recognition of the safety and effectiveness" of the mercury ingredients in these products.<ref>{{cite web |url=http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=310.545&SearchTerm=mercury|title=Title 21—Food and Drugs Chapter I—Food and Drug Administration Department of Health and Human Services Subchapter D—Drugs for Human Use Code of federal regulations |publisher=United States Food and Drug Administration|access-date=1 May 2007|url-status=live|archive-url=https://web.archive.org/web/20070313135424/http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=310.545&SearchTerm=mercury|archive-date=13 March 2007}}</ref>

===Production of chlorine and caustic soda===
[[Chemistry:Chlorine|Chlorine]] is produced from [[Chemistry:Sodium chloride|sodium chloride]] (common salt, NaCl) using [[Chemistry:Electrolysis|electrolysis]] to separate the metallic [[Chemistry:Sodium|sodium]] from the chlorine gas. Usually the salt is dissolved in water to produce a brine. By-products of any such [[Physics:Chloralkali process|chloralkali process]] are hydrogen (H<sub>2</sub>) and [[Chemistry:Sodium hydroxide|sodium hydroxide]] (NaOH), which is commonly called caustic soda or [[Chemistry:Lye|lye]]. By far the largest use of mercury<ref>{{cite journal|title=The CRB Commodity Yearbook (annual)|journal= The CRB Commodity Yearbook|date= 2000|page=173|issn=1076-2906}}</ref><ref name="USEPA">{{cite web|url=http://www.epa.gov/nrmrl/pubs/600r02104/600r02104chap3.pdf|author=Leopold, B. R.|date=2002|title=Chapter 3: Manufacturing Processes Involving Mercury. ''Use and Release of Mercury in the United States''|publisher=National Risk Management Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Cincinnati, Ohio|access-date=1 May 2007 |archive-url = https://web.archive.org/web/20070621093346/http://www.epa.gov/nrmrl/pubs/600r02104/600r02104chap3.pdf |archive-date = 21 June 2007}}</ref> in the late 20th century was in the mercury cell process (also called the Castner-Kellner process) where metallic sodium is formed as an [[Chemistry:Amalgam|amalgam]] at a [[Physics:Cathode|cathode]] made from mercury; this sodium is then reacted with water to produce sodium hydroxide.<ref>{{cite web|url=http://www.eurochlor.org/animations/mercury-cell.asp| title=Chlorine Online Diagram of mercury cell process| publisher=Euro Chlor| access-date=15 September 2006| archive-url=https://web.archive.org/web/20060902010053/http://www.eurochlor.org/animations/mercury-cell.asp <!--Added by H3llBot-->| archive-date=2 September 2006}}</ref> Many of the industrial mercury releases of the 20th century came from this process, although modern plants claim to be safe in this regard.<ref name="USEPA" /> From the 1960s onward, the majority of industrial plants moved away from mercury cell processes towards [[Chemistry:Sodium hydroxide#Production|diaphragm cell technologies]] to produce chlorine, though 11% of the chlorine made in the United States was still produced with the mercury cell method as of 2005.<ref>{{Cite book|date=2005|chapter-url=https://link.springer.com/chapter/10.1007/0-306-48624-5_2|title=Handbook of Chlor-Alkali Technology |chapter=History of the Chlor-Alkali Industry |pages=17–36|editor-last=O'Brien|editor-first=Thomas F.|place=Boston, MA|publisher=Springer |language=en|doi=10.1007/0-306-48624-5_2|isbn=978-0-306-48624-1|access-date=2020-10-05|editor2-last=Bommaraju|editor2-first=Tilak V.|editor3-last=Hine|editor3-first=Fumio}}</ref>

===Laboratory uses===
====Thermometers====
[[Chemistry:Mercury-in-glass thermometer|Thermometers]] containing mercury were invented in the early 18th century by [[Biography:Daniel Gabriel Fahrenheit|Daniel Gabriel Fahrenheit]], though earlier attempts at making temperature-measuring instruments filled with quicksilver had been described in the 1650s.<ref name="middleton">{{Cite book |last=Middleton |first=W. E. K. |url=http://archive.org/details/thermometer0000unse |title=A history of the thermometer and its use in meteorology |publisher=Johns Hopkins Press|year=1966|isbn=9780801871535}}</ref>{{rp|23}} Fahrenheit's mercury thermometer was based off an earlier design that used alcohol rather than mercury; the mercury thermometer was significantly more accurate than those using alcohol.<ref>Grigull, Ulrich (1966). ''Fahrenheit, a Pioneer of Exact Thermometry''. (The Proceedings of the 8th International Heat Transfer Conference, San Francisco, 1966, Vol. 1, pp. 9–18.)</ref> From the early 21st century onwards, the use of mercury thermometers has been declining, and mercury-containing instruments have been banned in many jurisdictions following the 1998 Protocol on Heavy Metals.<ref>{{cite web|url=http://www.unece.org/env/lrtap/hm_h1.html|title=Protocol on Heavy Metals|publisher=UNECE |access-date=10 August 2014}}</ref><ref>{{cite news|title = Mercury Reduction Act of 2003|url = https://openlibrary.org/b/OL17617678M|access-date = 6 June 2009|publisher = United States. Congress. Senate. Committee on Environment and Public Works}}</ref> Modern alternatives to mercury thermometers include [[Engineering:Resistance thermometer|resistance thermometer]]s, [[Physics:Thermocouple|thermocouple]]s, and [[Engineering:Thermistor|thermistor]] sensors that output to a digital display.<ref>{{cite web|title=Mercury Thermometer Alternatives: Hg Alternatives|publisher=National Institute of Standards and Technology|website=nist.gov|url=https://www.nist.gov/pml/mercury-thermometer-alternatives/mercury-thermometer-alternatives-hg-alternatives|date= 29 November 2021|access-date=22 December 2023}}</ref>

====Mirrors====
Some [[Astronomy:Meridian circle#Structure|transit telescopes]] use a basin of mercury to form a flat and absolutely horizontal mirror, useful in determining an absolute vertical or perpendicular reference. Concave horizontal parabolic mirrors may be formed by rotating liquid mercury on a disk, the parabolic form of the liquid thus formed reflecting and focusing incident light. Such [[Astronomy:Liquid-mirror telescope|liquid-mirror telescope]]s are cheaper than conventional large mirror telescopes by up to a factor of 100, but the mirror cannot be tilted and always points straight up.<ref>{{cite web|archive-url=https://web.archive.org/web/20030818233315/http://www.govertschilling.nl/artikelen/science/030314_sc.htm|url=http://www.govertschilling.nl/artikelen/science/030314_sc.htm|title=Liquid-mirror telescope set to give stargazing a new spin|date=14 March 2003|archive-date=18 August 2003|publisher=Govert Schilling|access-date=11 October 2008}}</ref><ref>{{cite journal |author=Gibson, B. K. |date=1991 |title=Liquid Mirror Telescopes: History |journal=Journal of the Royal Astronomical Society of Canada |volume=85 |page=158 |bibcode=1991JRASC..85..158G}}</ref><ref>{{cite web|access-date=24 June 2011|url=http://wood.phy.ulaval.ca/index.php/Rotating_Liquid_Mirrors|title=Laval University Liquid mirrors and adaptive optics group|archive-url=https://web.archive.org/web/20110918101521/http://wood.phy.ulaval.ca/index.php/Rotating_Liquid_Mirrors|archive-date=18 September 2011}}</ref>

====Electrochemistry====
Liquid mercury is part of a popular secondary reference [[Physics:Electrode|electrode]] (called the [[Chemistry:Mercury(I) chloride|calomel electrode]]) in [[Chemistry:Electrochemistry|electrochemistry]] as an alternative to the [[Physics:Standard hydrogen electrode|standard hydrogen electrode]]. The calomel electrode is used to work out the [[Chemistry:Electrode potential|electrode potential]] of half cells.<ref>{{cite book|url=https://books.google.com/books?id=M5pOAAAAIAAJ&pg=PA175|page=175|title=Physiological monitoring and instrument diagnosis in perinatal and neonatal medicine|author=Brans, Y W|author2=Hay W W|publisher=CUP Archive|date= 1995|isbn=978-0-521-41951-2}}</ref> The [[Chemistry:Triple point|triple point]] of mercury, −38.8344&nbsp;°C, is a fixed point used as a temperature standard for the International Temperature Scale (ITS-90).<ref name="CRC" />

====Polarography and crystallography====
In [[Physics:Polarography|polarography]], both the [[Physics:Dropping mercury electrode|dropping mercury electrode]]<ref>{{Cite book
| publisher = Elsevier Science
| isbn = 978-0-444-51958-0
| last = Zoski
| first = Cynthia G.
| title = Handbook of Electrochemistry
| date = 7 February 2007
}}</ref> and the [[Physics:Hanging mercury drop electrode|hanging mercury drop electrode]]<ref>{{Cite book
| edition = 2nd
| publisher = CRC
| isbn = 978-0-8247-9445-3
| last1 = Kissinger
| first1 = Peter
| first2 = William R. | last2 = Heineman
| title = Laboratory Techniques in Electroanalytical Chemistry, Second Edition, Revised and Expanded
| date = 23 January 1996
}}</ref> use elemental mercury. This use allows a new uncontaminated electrode to be available for each measurement or each new experiment.

Mercury-containing compounds are also of use in the field of [[Biology:Structural biology|structural biology]]. Mercuric compounds such as [[Chemistry:Mercury(II) chloride|mercury(II) chloride]] or [[Chemistry:Potassium tetraiodomercurate(II)|potassium tetraiodomercurate(II)]] can be added to [[Biology:Protein crystallization|protein crystals]] in an effort to create heavy atom derivatives that can be used to solve the [[Phase problem|phase problem]] in [[Physics:X-ray crystallography|X-ray crystallography]] via isomorphous replacement or [[Physics:Anomalous scattering|anomalous scattering]] methods.<ref>{{Cite journal |last1=Pike |first1=Ashley C. W. |last2=Garman |first2=Elspeth F. |last3=Krojer |first3=Tobias |last4=von Delft |first4=Frank |last5=Carpenter |first5=Elisabeth P. |date=2016-03-01 |title=An overview of heavy-atom derivatization of protein crystals |journal=Acta Crystallographica. Section D, Structural Biology |volume=72 |issue=Pt 3 |pages=303–318 |doi=10.1107/S2059798316000401 |issn=2059-7983 |pmc=4784662 |pmid=26960118|bibcode=2016AcCrD..72..303P }}</ref>

===Niche uses===
Gaseous mercury is used in [[Physics:Mercury-vapor lamp|mercury-vapor lamp]]s and some "neon sign" type advertising signs and [[Physics:Fluorescent lamp|fluorescent lamp]]s. Those low-pressure lamps emit very spectrally narrow lines, which are traditionally used in optical spectroscopy for calibration of spectral position. Commercial calibration lamps are sold for this purpose; reflecting a fluorescent ceiling light into a spectrometer is a common calibration practice.<ref>{{cite book|title = A guide to the use and calibration of detector array equipment| author = Hopkinson, G. R.| author2 = Goodman, T. M.| author3 = Prince, S. R.| publisher = SPIE Press| date = 2004| page = 125| isbn = 978-0-8194-5532-1| bibcode = 2004gucd.book.....H}}</ref> Gaseous mercury is also found in some electron tubes, including ignitrons, thyratrons, and mercury arc rectifiers.<ref>{{cite book|author=Howatson A H|title=An Introduction to Gas Discharges|isbn=978-0-08-020575-5|publisher=Pergamon Press|location= Oxford|date= 1965|chapter=Chapter 8}}</ref> It is also used in specialist medical care lamps for skin tanning and disinfection.<ref>{{cite book|url=https://books.google.com/books?id=-_9lhR_z6j8C&pg=PA104|page=104|title=Transformation of human diploid fibroblasts|author=Milo G E|author2=Casto B C|publisher=CRC Press|date=1990|isbn=978-0-8493-4956-0}}</ref> Gaseous mercury is added to [[Physics:Cold cathode|cold cathode]] [[Chemistry:Argon|argon]]-filled lamps to increase the [[Physics:Ionization|ionization]] and [[Physics:Electrical conductivity|electrical conductivity]]. An argon-filled lamp without mercury will have dull spots and will fail to light correctly. Lighting containing mercury can be bombarded/oven pumped only once. When added to [[Chemistry:Neon|neon]] filled tubes, inconsistent red and blue spots are produced in the light emissions until the initial burning-in process is completed; eventually it will light a consistent dull off-blue color.<ref>{{cite book| page = 363| title= Phosphor handbook| author = Shionoya, S.| publisher = CRC Press| date = 1999| isbn = 978-0-8493-7560-6}}</ref>

<gallery widths="230" heights="160">
File:Germicidal UV discharge tube glow rotate.jpg|The deep violet glow of a mercury vapor discharge in a [[Physics:Germicidal lamp|germicidal lamp]], whose spectrum is rich in invisible ultraviolet radiation.
File:Mercuryvaporlamp.jpg|Skin tanner containing a low-pressure mercury vapor lamp and two infrared lamps, which act both as light source and [[Physics:Electrical ballast|electrical ballast]]
File:Leuchtstofflampen-chtaube050409.jpg|Assorted types of fluorescent lamps.
File:Deep Space Atomic Clock-DSAC.jpg|The miniaturized [[Physics:Deep Space Atomic Clock|Deep Space Atomic Clock]] is a linear ion-trap-based mercury ion clock, designed for precise and real-time radio navigation in deep space.
</gallery>

The [[Physics:Deep Space Atomic Clock|Deep Space Atomic Clock]] (DSAC) under development by the [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]] utilises mercury in a linear ion-trap-based clock. The novel use of mercury permits the creation of compact atomic clocks with low energy requirements ideal for space probes and Mars missions.<ref>{{cite journal|year=2016|volume=63|issue=7|pages=1034–1043|journal=IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control|title=Mercury Ion Clock for a NASA Technology Demonstration Mission|doi=10.1109/TUFFC.2016.2543738|pmid=27019481|author=Robert L. Tjoelker|bibcode=2016ITUFF..63.1034T|s2cid=3245467|display-authors=0}}</ref>

====Skin whitening====
Mercury is effective as an active ingredient in skin whitening compounds used to depigment skin.<ref>{{cite journal |last1=Mohammed |first1=Terry |last2=Mohammed |first2=Elisabeth |last3=Bascombe |first3=Shermel |title=The evaluation of total mercury and arsenic in skin bleaching creams commonly used in Trinidad and Tobago and their potential risk to the people of the Caribbean |journal=Journal of Public Health Research |date=9 October 2017 |volume=6 |issue=3 |page=1097 |doi=10.4081/jphr.2017.1097 |pmid=29291194 |pmc=5736993 }}</ref>   The Minamata Convention on Mercury limits the concentration of mercury in such whiteners to 1 part per million.  However, as of 2022, many commercially sold whitener products continue to exceed that limit, and are considered toxic.<ref>Meera Senthilingam, "Skin whitening creams containing high levels of mercury continue to be sold on the world's biggest e-commerce sites, new report finds", 9 March 2022, CNN https://www.cnn.com/2022/03/09/world/zmwg-skin-whitening-creams-mercury-ecommerce-sites-intl-cmd/index.html</ref>

===Firearms===
[[Chemistry:Mercury(II) fulminate|Mercury(II) fulminate]] is a primary explosive, which has mainly been used as a primer of a [[Engineering:Cartridge (firearms)|cartridge]] in firearms throughout the 19th and 20th centuries.<ref name=wisniak>{{cite journal | last=Wisniak | first=Jaime | title=Edward Charles Howard. Explosives, meteorites, and sugar | journal=Educación Química | publisher=Universidad Nacional Autonoma de Mexico | volume=23 | issue=2 | year=2012 |language=en| issn=0187-893X | doi=10.1016/s0187-893x(17)30114-3 | pages=230–239| doi-access=free }}</ref>

===Historic uses===
[[File:Mercury Switch without housing.jpg|thumb|A single-pole, single-throw (SPST) mercury switch]]

[[File:Barometer mercury column hg.jpg|thumb|upright|Mercury manometer to measure pressure]]

Many historic applications made use of the peculiar physical properties of mercury, especially as a dense liquid and a liquid metal:
* Quantities of liquid mercury ranging from {{convert|90|to|600|g|oz}} have been recovered from elite Maya tombs (100–700&nbsp;AD)<ref name="Yuhas" /> or ritual caches at six sites. This mercury may have been used in bowls as [[Engineering:Mirrors in Mesoamerican culture|mirrors]] for divinatory purposes. Five of these date to the Classic Period of Maya civilization (c. 250–900) but one example predated this.<ref>{{cite journal |last1=Healy |first1=Paul F. |first2=Marc G. |last2=Blainey |date=2011 |title=Ancient Maya Mosaic Mirrors: Function, Symbolism, And Meaning |journal=Ancient Mesoamerica |issue=2 |pages=229–244 (241) |doi=10.1017/S0956536111000241 |volume=22 |s2cid=162282151}}</ref>
* In Islamic Spain, it was used for filling decorative pools. Later, the American artist Alexander Calder built a [[Chemistry:Mercury fountain|mercury fountain]] for the Spanish Pavilion at the 1937 World Exhibition in Paris. The fountain is now on display at the Fundació Joan Miró in [[Place:Barcelona|Barcelona]].<ref>{{cite book |url=https://books.google.com/books?id=pgUfSrD4gzQC&pg=PA10 |page=10 |title=Mercury |author=Lew K. |publisher=The Rosen Publishing Group |date=2008 |isbn=978-1-4042-1780-5}}</ref>
* The [[Physics:Fresnel lens|Fresnel lens]]es of old lighthouses used to float and rotate in a bath of mercury which acted like a bearing.<ref>{{cite book |url=https://books.google.com/books?id=oY8nG-6B6v0C&pg=PA29 |page=29 |title=Lighthouses |publisher=Osprey Publishing |date=2003 |isbn=978-0-7478-0556-4 |author=Pearson L. F.}}</ref>
* Mercury [[Engineering:Sphygmomanometer|sphygmomanometer]]s, [[Engineering:Barometer|barometer]]s, diffusion pumps, [[Chemistry:Mercury coulometer|coulometers]], and many other laboratory instruments took advantage of mercury's properties as a very dense, opaque liquid with a nearly linear thermal expansion.<ref>{{cite book |url=https://books.google.com/books?id=G8QyI1Nf0VQC&pg=PA251 |page=251 |title=AIEEE Chemistry |author=Ramanathan E. |publisher=Sura Books |isbn=978-81-7254-293-1}}</ref>
* As an electrically conductive liquid, it was used in [[Chemistry:Mercury switch|mercury switch]]es (including [[Engineering:Light switch#Mercury switch|home mercury light switches]] installed prior to 1970), tilt switches used in old fire detectors and in some home thermostats.<ref>{{cite book |url=https://books.google.com/books?id=cxPEiSXh44cC&pg=PA260 |page=260 |title=Electrical Installations |author=Shelton, C. |publisher=Nelson Thornes |date=2004 |isbn=978-0-7487-7979-6}}</ref>
* Owing to its acoustic properties, mercury was used as the propagation medium in [[Delay-line memory#Mercury delay lines|delay-line memory]] devices used in early digital computers of the mid-20th century, such as the SEAC computer.<ref>{{cite journal|journal=Proceedings of the IRE|first=J. P.|last=Eckert|title=A Survey of Digital Computer Memory Systems|date=October 1953|volume=41|issue=10 |pages=1393–1406 |doi=10.1109/JRPROC.1953.274316}}</ref>
* In 1911, [[Biography:Heike Kamerlingh Onnes|Heike Kamerlingh Onnes]] discovered [[Physics:Superconductivity|superconductivity]] through the cooling of mercury below 4 kelvin shortly after the discovery and production of [[Chemistry:Liquid helium|liquid helium]].<ref>{{Cite web |last1=van Delft |first1=Dirk |last2=Kes |first2=Peter |date=2010-09-01 |title=The discovery of superconductivity |url=https://pubs.aip.org/physicstoday/article/63/9/38/386608/The-discovery-of-superconductivityA-century-ago |url-status=live |archive-url=https://web.archive.org/web/20231114035120/https://pubs.aip.org/physicstoday/article/63/9/38/386608/The-discovery-of-superconductivityA-century-ago |archive-date=2023-11-14 |access-date=2023-12-06 |website=Physics Today}}</ref> Its superconductive properties were later determined to be unusual compared to other later-discovered superconductors, such as the more popular niobium alloys.<ref>{{Cite journal |last1=Tresca |first1=Cesare |last2=Profeta |first2=Gianni |last3=Marini |first3=Giovanni |last4=Bachelet |first4=Giovanni B. |last5=Sanna |first5=Antonio |last6=Calandra |first6=Matteo |last7=Boeri |first7=Lilia |date=2022-11-03 |title=Why mercury is a superconductor |url=https://link.aps.org/doi/10.1103/PhysRevB.106.L180501 |journal=Physical Review B |language=en |volume=106 |issue=18 |doi=10.1103/PhysRevB.106.L180501 |arxiv=2111.13867 |bibcode=2022PhRvB.106r0501T |issn=2469-9950|hdl=11573/1659661 |s2cid=244715089 |hdl-access=free }}</ref><ref>{{cite journal |author=Berlincourt |first1=T. G. |last2=Hake |first2=R. R. |name-list-style=amp |date=1962 |title=Pulsed-Magnetic-Field Studies of Superconducting Transition Metal Alloys at High and Low Current Densities |journal=Bulletin of the American Physical Society |volume=II-7 |page=408}}</ref>
* Experimental mercury vapor turbines were installed to increase the efficiency of fossil-fuel electrical power plants.<ref>{{cite journal |url=https://books.google.com/books?id=9ycDAAAAMBAJ&pg=PA40 |page=40 |title=Popular Science |journal=The Popular Science Monthly |date=1931 |volume=118 |number=3 |issn=0161-7370 |publisher=Bonnier Corporation}}</ref> The South Meadow power plant in Hartford, CT employed mercury as its [[Physics:Working fluid|working fluid]], in a binary configuration with a secondary water circuit, for a number of years starting in the late 1920s in a drive to improve plant efficiency. Several other plants were built, including the Schiller Station in Portsmouth, NH, which went online in 1950. The idea did not catch on industry-wide due to the weight and toxicity of mercury, as well as the advent of [[Physics:Supercritical fluid|supercritical]] steam plants in later years.<ref>{{cite book |url=https://books.google.com/books?id=FigDAAAAMBAJ&pg=PA22 |title=Cheaper Power from Quicksilver |author=Mueller, Grover C. |date=September 1929 |publisher=Popular Science}}</ref><ref>{{cite web |url= http://www.aqpl43.dsl.pipex.com/MUSEUM/POWER/mercury/mercury.htm |date=13 November 2008 |work=Museum of Retro Technology |title=Mercury as a Working Fluid |archive-url=https://web.archive.org/web/20110221034317/http://www.aqpl43.dsl.pipex.com/MUSEUM/POWER/mercury/mercury.htm |archive-date=21 February 2011}}</ref>
* Similarly, liquid mercury was used as a [[Physics:Coolant|coolant]] for some [[Physics:Nuclear reactor|nuclear reactor]]s; however, [[Chemistry:Sodium|sodium]] is proposed for reactors cooled with liquid metal, because the high density of mercury requires much more energy to circulate as coolant.<ref>{{cite book |url=https://books.google.com/books?id=2KYVftKE9NUC&pg=PA64 |page=64 |title=Introduction to Nuclear Power |author=James Collier |author2=Geoffrey F. Hewitt |publisher=Taylor & Francis |date=1987 |isbn=978-1-56032-682-3}}</ref>
* Mercury was a propellant for early ion engines in [[Engineering:Electrically powered spacecraft propulsion|electric space propulsion]] systems. Advantages were mercury's high molecular weight, low ionization energy, low dual-ionization energy, high liquid density and liquid storability at [[Physics:Room temperature|room temperature]]. Disadvantages were concerns regarding environmental impact associated with ground testing and concerns about eventual cooling and condensation of some of the propellant on the spacecraft in long-duration operations. The first spaceflight to use electric propulsion was a mercury-fueled ion thruster developed at NASA Glenn Research Center and flown on the Space Electric Rocket Test "[[Engineering:SERT-1|SERT-1]]" spacecraft launched by [[Organization:NASA|NASA]] at its [[Organization:Wallops Flight Facility|Wallops Flight Facility]] in 1964. The SERT-1 flight was followed up by the SERT-2 flight in 1970. Mercury and [[Chemistry:Caesium|caesium]] were preferred propellants for ion engines until Hughes Research Laboratory performed studies finding [[Chemistry:Xenon|xenon]] gas to be a suitable replacement. Xenon is now the preferred propellant for ion engines, as it has a high molecular weight, little or no reactivity due to its [[Chemistry:Noble gas|noble gas]] nature, and high liquid density under mild cryogenic storage.<ref>{{cite web |publisher=NASA |access-date=7 July 2009 |url=http://www.nasa.gov/centers/glenn/about/history/ds1.html |title=Glenn Contributions to Deep Space 1 |date=21 May 2008 |url-status=live |archive-url=https://web.archive.org/web/20091001110901/http://www.nasa.gov/centers/glenn/about/history/ds1.html |archive-date=1 October 2009}}</ref><ref>{{cite encyclopedia |encyclopedia=The Internet Encyclopedia of Science |publisher=David Darling |access-date=7 July 2009 |url= http://www.daviddarling.info/encyclopedia/E/electricprop.html |title=Electric space propulsion |url-status=live |archive-url=https://web.archive.org/web/20090530080218/http://www.daviddarling.info/encyclopedia/E/electricprop.html |archive-date=30 May 2009}}</ref>

Other applications made use of the chemical properties of mercury:
* The [[Chemistry:Mercury battery|mercury battery]] is a non-rechargeable [[Chemistry:Electrochemical cell|electrochemical battery]], a [[Physics:Primary cell|primary cell]], that was common in the middle of the 20th century. It was used in a wide variety of applications and was available in various sizes, particularly button sizes. Its constant voltage output and long shelf life gave it a niche use for camera light meters and hearing aids. The mercury cell was effectively banned in most countries in the 1990s due to concerns about the mercury contaminating landfills.<ref>{{cite web |title=IMERC Fact Sheet: Mercury Use in Batteries| url=http://www.newmoa.org/prevention/mercury/imerc/factsheets/batteries.cfm |publisher=Northeast Waste Management Officials' Association |access-date=20 June 2013| date=January 2010 |archive-url=https://web.archive.org/web/20121129031541/http://www.newmoa.org/prevention/mercury/imerc/factsheets/batteries.cfm |archive-date=29 November 2012}}</ref>
* Mercury was used for preserving wood, developing [[Chemistry:Daguerreotype|daguerreotype]]s, [[Chemistry:Mercury silvering|silvering mirrors]],<ref>{{Citation|title=Mercury Silvering |url=//www.thebritishmuseum.ac.uk/science/text/treasure/sr-treasure-merc-t.html |accessdate=2010-02-12 |postscript=. |url-status=dead |archiveurl=https://web.archive.org/web/20050304114237/http://www.thebritishmuseum.ac.uk/science/text/treasure/sr-treasure-merc-t.html |archivedate=March 4, 2005 }}</ref> [[Engineering:Anti-fouling paint|anti-fouling paint]]s,<ref>{{cite web|archive-url=https://web.archive.org/web/20070310132413/http://openchemist.net/chemistry/show.php?id=analytical&story=env001|archive-date=10 March 2007|url-status=dead|url=http://openchemist.net/chemistry/show.php?id=analytical&story=env001|website=Open Chemist|title=Organotin Compounds in the Environment}}</ref> [[Biology:Herbicide|herbicide]]s,<ref>{{cite journal|journal=Residue Reviews|title=Use and residues of mercury compounds in agriculture|first=N. A.|last=Smart|date=1968 |pages=1–36 |doi=10.1007/978-1-4615-8437-7_1|pmid=4875698 |isbn=978-1-4615-8439-1 }}</ref> interior latex paint, handheld maze games, cleaning, and road leveling devices in cars. Mercury compounds have been used in [[Chemistry:Antiseptic|antiseptic]]s, laxatives, [[Chemistry:Antidepressant|antidepressant]]s, and in [[Medicine:Syphilis|antisyphilitics]].<ref name="lincoln" /> Mercury has been replaced with safer compounds in most, if not all, of these applications.
* It was allegedly used by allied spies to sabotage Luftwaffe planes: a mercury paste was applied to bare [[Chemistry:Aluminium|aluminium]], causing the metal to rapidly [[Chemistry:Corrosion|corrode]]; this would cause structural failures.<ref name="Gray">{{cite web| author=Gray, T.| title=The Amazing Rusting Aluminum| publisher=Popular Science| date=22 September 2004| url=http://www.popsci.com/scitech/article/2004-09/amazing-rusting-aluminum| access-date=7 July 2009| archive-url=https://web.archive.org/web/20090720053255/http://www.popsci.com/scitech/article/2004-09/amazing-rusting-aluminum| archive-date=20 July 2009| url-status=live}}</ref>
* Mercury was once used as a gun barrel bore cleaner.<ref>{{cite book |last=Francis |first=G. W. |title=Chemical Experiments |publisher=D. Francis |date=1849 |page=62 |url=https://archive.org/details/chemicalexperim01frangoog}}</ref><ref>{{cite book |author=Castles, W. T. |author2=Kimball, V. F. |title=Firearms and Their Use |publisher=Kessinger Publishing |date=2005 |page=104 |isbn=978-1-4179-8957-7}}</ref>
* From the mid-18th to the mid-19th centuries, a process called "carroting" was used in the making of felt hats. Animal skins were rinsed in an orange solution (the term "carroting" arose from this color) of the mercury compound mercuric nitrate, Hg(NO<sub>3</sub>)<sub>2</sub>·2H<sub>2</sub>O.<ref>{{cite book |title=Concise Inorganic Chemistry |author=Lee, J. D. |publisher=Wiley-Blackwell |date=1999 |isbn=978-0-632-05293-6}}</ref> This process separated the fur from the pelt and matted it together. This solution and the vapors it produced were highly toxic. The United States Public Health Service banned the use of mercury in the felt industry in December 1941. The psychological symptoms associated with mercury poisoning inspired the phrase "mad as a hatter". [[Biography:Lewis Carroll|Lewis Carroll]]'s "Mad Hatter" in his book ''Alice's Adventures in Wonderland'' was a play on words based on the older phrase, but the character himself does not exhibit symptoms of mercury poisoning.<ref>{{cite journal |journal=Br. Med. J. (Clin. Res. Ed.) |date=1983 |volume=287 |page=1961 |title=Did the Mad Hatter have mercury poisoning? |author=Waldron, H. A. |pmid=6418283 |doi=10.1136/bmj.287.6409.1961 |issue=6409 |pmc=1550196}}</ref><!--<ref>https://www.jstor.org/stable/139669</ref>-->
* Historically, mercury was used extensively in [[Engineering:Hydraulic mining|hydraulic gold mining]] in order to help the gold to sink through the flowing water-gravel mixture. Thin gold particles may form mercury-gold amalgam and therefore increase the gold recovery rates.<ref name="CRC" /> Large-scale use of mercury stopped in the 1960s. However, mercury is still used in small scale, often clandestine, gold prospecting. It is estimated that 45,000 metric tons of mercury used in California for [[Earth:Placer mining|placer mining]] have not been recovered.<ref>{{cite web |url=http://pubs.usgs.gov/fs/2005/3014/ |title=Mercury Contamination from Historical Gold Mining in California |access-date=26 February 2008 |author=Alpers, C. N. |author2=Hunerlach, M. P. |author3=May, J. Y. |author4=Hothem, R. L. |publisher=U.S. Geological Survey |url-status=live |archive-url=https://web.archive.org/web/20080222034946/http://pubs.usgs.gov/fs/2005/3014/ |archive-date=22 February 2008}}</ref> Mercury was also used in silver mining to extract the metal from ore through the [[Chemistry:Patio process|patio process]].<ref>{{cite web |url=http://corrosion-doctors.org/Elements-Toxic/Mercury-amalgamation.htm |website=Corrosion Doctors |title=Mercury amalgamation |access-date=7 July 2009 |url-status=live| archive-url=https://web.archive.org/web/20090519051437/http://corrosion-doctors.org/Elements-Toxic/Mercury-amalgamation.htm |archive-date=19 May 2009 }}</ref>

==Toxicity and safety==
{{Chembox

| Name = Mercury
| container_only = yes
|Section7={{Chembox Hazards
| ExternalSDS =
| GHSPictograms = {{GHS06}}{{GHS08}}{{GHS09}}
| GHSSignalWord = Danger
| HPhrases = {{H-phrases|330|360D|372|410}}
| PPhrases = {{P-phrases|201|260|273|280|304|340|310|308|313|391|403|233}}<ref>{{Cite web|url=https://www.sigmaaldrich.com/catalog/product/aldrich/294594|title=Mercury 294594|website=Sigma-Aldrich}}</ref>
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 0
| NFPA-S = 
| NFPA_ref = 
 }}
}}
Mercury can be absorbed through the skin and mucous membranes and mercury vapors can be inhaled, so containers of mercury are securely sealed to avoid spills and evaporation. Heating of mercury, or of compounds of mercury that may decompose when heated, should be carried out with adequate ventilation in order to minimize exposure to mercury vapor. The most toxic forms of mercury are its organic compounds, such as [[Chemistry:Dimethylmercury|dimethylmercury]] and [[Chemistry:Methylmercury|methylmercury]]. Mercury can cause both chronic and acute poisoning.<ref name="acutepoisoning">{{cite journal|author=McFarland, RB |author2=Reigel, H|name-list-style=amp|journal=J. Occup. Med. |date=1978 |volume=20|issue=8|pages=532–4 |doi=10.1097/00043764-197808000-00003 |title=Chronic Mercury Poisoning from a Single Brief Exposure|pmid=690736}}</ref><ref name="chronicpoisoning" >{{EHC-ref |id=001 |name=Mercury |date=1976 |isbn=92-4-154061-3}}</ref>

===Releases in the environment===
[[File:Mercury in Ice Core Upper Fremont Glacier.svg|thumb|right|Amount of atmospheric mercury deposited at Wyoming's Upper Fremont Glacier over the last 270 years]]

Preindustrial deposition rates of mercury from the atmosphere may be about 4&nbsp;ng per 1 L of ice deposited. Volcanic eruptions and related natural sources are responsible for approximately half of atmospheric mercury emissions.<ref>{{cite web |url=http://toxics.usgs.gov/pubs/FS-051-02/|title=Glacial Ice Cores Reveal A Record of Natural and Anthropogenic Atmospheric Mercury Deposition for the Last 270 Years |publisher=United States Geological Survey (USGS)|access-date=1 May 2007|url-status=live|archive-url=https://web.archive.org/web/20070704010753/http://toxics.usgs.gov/pubs/FS-051-02/|archive-date=4 July 2007}}</ref>

Atmospheric mercury contamination in outdoor urban air at the start of the 21st century was measured at 0.01–0.02&nbsp;μg/m<sup>3</sup>. A 2001 study measured mercury levels in 12 indoor sites chosen to represent a cross-section of building types, locations and ages in the New York area. This study found mercury concentrations significantly elevated over outdoor concentrations, at a range of 0.0065&nbsp;– 0.523&nbsp;μg/m<sup>3</sup>. The average was 0.069&nbsp;μg/m<sup>3</sup>.<ref>{{cite web |date=May 2003 |publisher=Northeast Waste Management Officials' Association  |url=http://www.newmoa.org/prevention/mercury/MercuryIndoor.pdf |access-date=7 July 2009 |title=Indoor Air Mercury|archive-url=https://web.archive.org/web/20090325210734/http://www.newmoa.org/prevention/mercury/MercuryIndoor.pdf|archive-date=25 March 2009}}</ref>

Half of mercury emissions are attributed to mankind. The sources can be divided into the following estimated percentages:<ref name="Pacyna"/>
* 65% from stationary combustion, of which coal-fired power plants are the largest aggregate source (40% of U.S. mercury emissions in 1999). This includes power plants fueled with gas where the mercury has not been removed. Emissions from coal combustion are between one and two orders of magnitude higher than emissions from oil combustion, depending on the country.<ref name="Pacyna" />
* 11% from gold production. The three largest point sources for mercury emissions in the U.S. are the three largest gold mines. Hydrogeochemical release of mercury from gold-mine tailings has been accounted as a significant source of atmospheric mercury in eastern Canada.<ref>{{cite journal |doi=10.1021/es048962j |pmid=15819225 |title=Determination of Mercury Evasion in a Contaminated Headwater Stream |date=2005 |last1=Maprani |first1=Antu C. |journal=Environmental Science & Technology |volume=39 |issue=6 |pages=1679–87 |last2=Al |first2=Tom A. |last3=MacQuarrie |first3=Kerry T. |last4=Dalziel |first4=John A. |last5=Shaw |first5=Sean A. |last6=Yeats |first6=Phillip A. |bibcode=2005EnST...39.1679M}}</ref>
* 6.8% from [[Chemistry:Non-ferrous metal|non-ferrous metal]] production, typically smelters.
* 6.4% from cement production.
* 3.0% from waste disposal, including municipal and hazardous waste, crematoria, and [[Engineering:Sewage sludge|sewage sludge]] incineration.
* 3.0% from caustic soda production.
* 1.4% from [[Chemistry:Pig iron|pig iron]] and steel production.
* 1.1% from mercury production, mainly for batteries.
* 2.0% from other sources.
The above percentages are estimates of the global human-caused mercury emissions in 2000, excluding biomass burning, an important source in some regions.<ref name="Pacyna">{{cite journal |journal= Atmos Environ |date=2006 |volume=40 |issue=22 |page=4048|title= Global anthropogenic mercury emission inventory for 2000 |author= Pacyna E G |author2= Pacyna J M |author3= Steenhuisen F |author4= Wilson S |doi=10.1016/j.atmosenv.2006.03.041|bibcode = 2006AtmEn..40.4048P }}</ref>

A serious industrial disaster was the dumping of waste mercury compounds into Minamata Bay, Japan, between 1932 and 1968. It is estimated that over 3,000 people suffered various deformities, severe mercury poisoning symptoms or death from what became known as Minamata disease.<ref name="auto1">{{cite web|url=http://www.env.go.jp/en/chemi/hs/minamata2002/|title=Minamata Disease The History and Measures|publisher=Ministry of the Environment, Government of Japan|access-date=7 July 2009|url-status=live|archive-url=https://web.archive.org/web/20090624205922/http://www.env.go.jp/en/chemi/hs/minamata2002/|archive-date=24 June 2009}}</ref><ref name="auto">{{cite journal |author=Dennis Normile |title=In Minamata, Mercury Still Divides |journal=Science |volume=341 |issue=6153 |pages=1446–7 |date=27 September 2013 |doi=10.1126/science.341.6153.1446 |bibcode=2013Sci...341.1446N |pmid=24072902}}</ref>

China is estimated to produce 50% of the mercury emissions, most of which result from the production of [[Chemistry:Vinyl chloride|vinyl chloride]].<ref name="Pagliaro 2016">{{Cite journal|last1=Ciriminna|first1=Rosaria|last2=Falletta|first2=Ermelinda|last3=Della Pina|first3=Cristina|last4=Teles|first4=Joaquim Henrique|last5=Pagliaro|first5=Mario|date=2016|title=Industrial Applications of Gold Catalysis|journal=Angewandte Chemie International Edition|volume=55|issue=46|pages=1433–7851|doi=10.1002/anie.201604656|pmid=27624999 |hdl=2434/463818|s2cid=28730917 |hdl-access=free}}</ref>
<!--
Artificial lakes, or [[Earth:Reservoir|reservoir]]s, may be contaminated with mercury due to the absorption by the water of mercury from submerged trees and soil.
For example, Williston Lake in northern British Columbia, created by the damming of the Peace River in 1968, is still sufficiently contaminated with mercury that it is inadvisable to consume fish from the lake.<ref>{{cite web |url=https://www.cbc.ca/news/canada/british-columbia/west-moberly-first-nations-concerned-about-mercury-contamination-in-fish-1.3070702 |title=West Moberly First Nations concerned about mercury contamination in fish |last=Meissner |first=Dirk |agency=The Canadian Press |work=CBC News |date=12 May 2015 |access-date=20 July 2021 }}</ref><ref>{{cite web |url=http://a100.gov.bc.ca/appsdata/acat/documents/r54457/CO94394_FinalReport-FIsh_Mercury_Investigation-Az_1531852633378_1851380586.pdf |title=Williston-Dinosaur Watershed Fish Mercury Investigation: 2017 Report |publisher=Fish and Wildlife Compensation Program, Peace Region |date= June 2018 |access-date=20 July 2021 }}</ref> [[Earth:Permafrost|Permafrost]] soils have accumulated mercury through atmospheric deposition,<ref>{{cite journal |last1=Schuster |first1=Paul |last2=Schaefer |first2=Kevin |last3=Aiken |first3=George |last4=Antweiler |first4=Ronald |last5=Dewild |first5=John |last6=Gryziec |first6=Joshua |last7=Gusmeroli |first7=Alessio |last8=Hugelius |first8=Gustaf |last9=Jafarov |first9=Elchin |last10=Krabbenhoft |first10=David |last11=Liu |first11=Lin |last12=Herman-Mercer |first12=Nicole |last13=Mu |first13=Cuicui |last14=Roth |first14=David |last15=Schaefer |first15=Tim |last16=Streigl |first16=Robert |last17=Wickland |first17=Kim |last18=Zhang |first18=Tingjun |display-authors=5| title=Permafrost Stores a Globally Significant Amount of Mercury |journal=Geophysical Research Letters |date=2018 |volume=45 |issue=3 |pages=1463–1471 |doi=10.1002/2017GL075571 |bibcode=2018GeoRL..45.1463S |doi-access=free }}</ref> and permafrost thaw in [[Physics:Cryosphere|cryospheric]] regions is also a mechanism of mercury release into lakes, rivers, and [[Earth:Wetland|wetland]]s.<ref>{{cite journal |last1=St. Pierre |first1=Kyra A. |last2=Zolkos |first2=Scott |last3=Shakil |first3=Sarah |last4=Tank |first4=Suzanne E. |last5=St. Louis |first5=Vincent L. |last6=Kokelj |first6=Steven V. |title=Unprecedented Increases in Total and Methyl Mercury Concentrations Downstream of Retrogressive Thaw Slumps in the Western Canadian Arctic |journal=Environmental Science & Technology |date=18 December 2018 |volume=52 |issue=24 |pages=14099–14109 |doi=10.1021/acs.est.8b05348 |pmid=30474969 |bibcode=2018EnST...5214099S |s2cid=53745081 }}</ref><ref>{{cite journal |last1=Ci |first1=Zhijia |last2=Peng |first2=Fei |last3=Xue |first3=Xian |last4=Zhang |first4=Xiaoshan |title=Permafrost Thaw Dominates Mercury Emission in Tibetan Thermokarst Ponds |journal=Environmental Science & Technology |date=5 May 2020 |volume=54 |issue=9 |pages=5456–5466 |doi=10.1021/acs.est.9b06712 |pmid=32294379 |bibcode=2020EnST...54.5456C |s2cid=215793015 }}</ref>

Historically, one of the largest releases was from the Colex plant, a [[Physics:Isotopes of lithium|lithium isotope]] separation plant at Oak Ridge, Tennessee. The plant operated in the 1950s and 1960s. Records are incomplete and unclear, but government commissions have estimated that some two million pounds of mercury are unaccounted for.<ref>{{cite web|publisher = United States Department of Energy|title = Introduction|url = http://www.hss.energy.gov/healthsafety/ohre/new/findingaids/epidemiologic/oakridge1/intro.html|archive-url = https://web.archive.org/web/20070708173535/http://www.hss.energy.gov/healthsafety/ohre/new/findingaids/epidemiologic/oakridge1/intro.html |archive-date = 8 July 2007}}</ref>
-->

[[File:Joss paper burning on the street, Tai Po, Hong Kong, 2023.webm|thumb|upright=0.85|Joss paper burning on the street, a common tradition practiced in Asia, Hong Kong, 2023]]
Mercury also enters into the environment through the improper disposal of mercury-containing products.<ref>{{cite web |url=http://www.epa.gov/epaoswer/non-hw/reduce/epr/products/mercury.htm|title=Mercury-containing Products|publisher=United States Environmental Protection Agency (EPA)|access-date=1 May 2007|url-status=live|archive-url=https://web.archive.org/web/20070212061414/http://www.epa.gov/epaoswer/non-hw/reduce/epr/products/mercury.htm|archive-date=12 February 2007}}</ref> Due to health concerns (see below), [[Social:Waste management|toxics use reduction]] efforts are cutting back or eliminating mercury in such products. For example, the amount of mercury sold in thermostats in the United States decreased from 14.5 tons in 2004 to 3.9 tons in 2007.<ref>{{cite web |url=http://www.newmoa.org/prevention/mercury/imerc/factsheets/thermostats.pdf |title=IMERC Fact Sheet: Mercury Use in Thermostats |archive-url=https://web.archive.org/web/20120617061326/http://www.newmoa.org/prevention/mercury/imerc/factsheets/thermostats.pdf |archive-date=17 June 2012 |date=January 2010 |publisher=Northeast Waste Management Officials' Association}}</ref>

The tobacco plant readily absorbs and accumulates [[Chemistry:Heavy metals|heavy metals]] such as mercury from the surrounding soil into its leaves. These are subsequently inhaled during [[Chemistry:Tobacco smoking|tobacco smoking]].<ref>{{cite journal |pmc=3586865 |year=2012 |last1=Pourkhabbaz |first1=A. |title=Investigation of Toxic Metals in the Tobacco of Different Iranian Cigarette Brands and Related Health Issues |journal=Iranian Journal of Basic Medical Sciences |volume=15 |issue=1 |pages=636–644 |last2=Pourkhabbaz |first2=H. |pmid=23493960}}</ref> While mercury is a constituent of [[Chemistry:Tobacco smoke|tobacco smoke]],<ref>{{cite journal |last1=Talhout |first1=Reinskje |last2=Schulz |first2=Thomas |last3=Florek |first3=Ewa |last4=Van Benthem |first4=Jan |last5=Wester |first5=Piet |last6=Opperhuizen |first6=Antoon |title=Hazardous Compounds in Tobacco Smoke |journal=International Journal of Environmental Research and Public Health |volume=8 |issue=12 |year=2011 |pages=613–628 |issn=1660-4601 |doi=10.3390/ijerph8020613 |pmid=21556207 |pmc=3084482 |doi-access=free}}</ref> studies have largely failed to discover a significant correlation between smoking and Hg uptake by humans compared to sources such as occupational exposure, fish consumption, and amalgam tooth fillings.<ref>{{cite journal |vauthors=Bernhard D, Rossmann A, Wick G |year=2005| title=Metals in Cigarette Smoke |journal=IUBMB Life |volume=57 |issue=12| pages=805–809 |doi=10.1080/15216540500459667 |pmid=16393783 |s2cid=35694266| doi-access=free}}</ref>

A less well-known source of mercury is the burning of [[Biology:Joss paper|joss paper]],<ref>{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/S0045653516313716 |title=How incense and joss paper burning during the worship activities influences ambient mercury concentrations in indoor and outdoor environments of an Asian temple?|year=2017 |doi=10.1016/j.chemosphere.2016.09.159 |last1=Shen |first1=Huazhen |last2=Tsai |first2=Cheng-Mou |last3=Yuan |first3=Chung-Shin |last4=Jen |first4=Yi-Hsiu |last5=Ie |first5=Iau-Ren |journal=Chemosphere |volume=167 |pages=530–540 |pmid=27764746 |bibcode=2017Chmsp.167..530S }}</ref> which is a common tradition practiced in Asia, including China,<ref>{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/S026974912200121X |title=Large contribution from worship activities to the atmospheric soot particles in northwest China|year=2022 |doi=10.1016/j.envpol.2022.118907 |last1=Lin |first1=Chunshui |last2=Huang |first2=Ru-Jin |last3=Duan |first3=Jing |last4=Zhong |first4=Haobin |last5=Xu |first5=Wei |last6=Wu |first6=Yunfei |last7=Zhang |first7=Renjian |journal=Environmental Pollution |volume=299 |page=118907 |pmid=35091017 |s2cid=246355499 }}</ref> Vietnam, Hong Kong, Thailand, Taiwan and Malaysia.<ref>{{cite web | url=https://www.researchgate.net/publication/233885602 | title=Parkinson's disease in occupational exposure to joss paper, a report of two cases}}</ref>

====Spill cleanup====

Mercury spills pose an immediate threat to people handling the material, in addition to being an environmental hazard if the material is not contained properly. This is of particular concern for visible mercury, or mercury in liquid state, as its unusual appearance and behavior for a metal makes it an [[Social:Attractive nuisance doctrine|attractive nuisance]] to the uninformed.<ref>{{cite journal|last=Azziz-Baumgartner |first=E |author-last2=Luber |author-first2=G|author-last3= Schurz-Rogers |author-first3=H|author-last4= Backer|author-first4= L|author-last5= Belson |author-first5=M|author-last6= Kieszak |author-first6=S|author-last7= Caldwell |author-first7=K|author-last8= Lee |author-first8=B|author-last9=
Jones|author-first9= R|date= 2007|title= Exposure assessment of a mercury spill in a Nevada school -- 2004|journal=Clin Toxicol|volume= 45|issue= 4|pages= 391–395|doi=10.1080/15563650601031569 |pmid=17486480 |s2cid=33770481 }}</ref> Procedures have been developed to contain mercury spills, as well as recommendations on appropriate responses based on the conditions of a spill.<ref>{{cite web|url=http://www.epa.gov/mercury/spills/index.htm|title=Mercury: Spills, Disposal and Site Cleanup|publisher=Environmental Protection Agency|access-date=11 August 2007|url-status=live|archive-url=https://web.archive.org/web/20080513130136/http://epa.gov/mercury/spills/index.htm|archive-date=13 May 2008}}</ref><ref>{{cite web|url=https://www.atsdr.cdc.gov/emergency_response/Action_Levels_for_Elemental_Mercury_Spills_2012.pdf|website=www.atsdr.cdc.gov|title=Action Levels for Elemental Mercury Spills|date=22 March 2012}}</ref> Tracking liquid mercury away from the site of a spill is a major concern in liquid mercury spills; regulations emphasize containment of the visible mercury as the first course of action, followed by monitoring of mercury vapors and vapor cleanup. Several products are sold as mercury spill [[Chemistry:Adsorption|adsorbents]], ranging from metal salts to polymers and [[Chemistry:Zeolite|zeolite]]s.<ref>{{cite journal|doi=10.1007/s11356-015-5880-x|title=Removal of mercury by adsorption: a review|journal=Environmental Science and Pollution Research|date=1 December 2015|last1=Yu|first1=Jin-Gang|first2= Bao-Yu |last2=Yue|first3= Xiong-Wei|last3= Wu|first4= Qi|last4= Liu|first5= Fei-Peng|last5= Jiao|first6= Xin-Yu|last6= Jiang |first7= Xiao-Qing|last7= Chen|volume=23|issue=6 |pages=5056–5076|s2cid=28365564 }}</ref>

===Sediment contamination===

Sediments within large urban-industrial estuaries act as an important sink for point source and diffuse mercury pollution within [[Earth:Drainage basin|catchments]].<ref name="VaneBeriro2015">{{cite journal |last1=Vane |first1=C.H. |last2=Beriro |first2=D.J. |last3=Turner |first3=G.H. |title=Rise and fall of mercury (Hg) pollution in sediment cores of the Thames Estuary, London, UK |journal=Earth and Environmental Science Transactions of the Royal Society of Edinburgh |volume=105|issue=4|year=2015|pages=285–296 |issn=1755-6910 |doi=10.1017/S1755691015000158|doi-access=free}}</ref> A 2015 study of foreshore sediments from the Thames estuary measured total mercury at 0.01 to 12.07&nbsp;mg/kg with mean of 2.10&nbsp;mg/kg and median of 0.85&nbsp;mg/kg (n=351).<ref name="VaneBeriro2015" /> The highest mercury concentrations were shown to occur in and around the city of [[Place:London|London]] in association with fine grain muds and high total organic carbon content.<ref name="VaneBeriro2015" /> The strong affinity of mercury for carbon rich sediments has also been observed in salt marsh sediments of the River Mersey, with a mean concentration of 2&nbsp;mg/kg, up to 5&nbsp;mg/kg.<ref name="VaneJones2009">{{cite journal |last1=Vane |first1=C.H. |last2=Jones |first2=D.G. |last3=Lister |first3=T.R. |title=Mercury contamination in surface sediments and sediment cores of the Mersey Estuary, UK |journal=Marine Pollution Bulletin |volume=58 |issue=6 |year=2009 |pages=940–946 |issn=0025-326X |doi=10.1016/j.marpolbul.2009.03.006 |pmid=19356771 |bibcode=2009MarPB..58..940V |url=http://nora.nerc.ac.uk/id/eprint/7405/1/Vane_et_al__2009_Mersey_Hg_9_3_09.pdf}}</ref> These concentrations are far higher than those in the salt marsh river creek sediments of New Jersey and [[Earth:Mangrove|mangrove]]s of Southern China, which exhibit low mercury concentrations of about 0.2&nbsp;mg/kg.<ref name="VaneHarrison2008">{{cite journal |last1=Vane |first1=C.H. |last2=Harrison |first2=I. |last3=Kim |first3=A.W. |last4=Moss-Hayes |first4=V. |last5=Vickers |first5=B.P. |last6=Horton |first6=B.P. |title=Status of organic pollutants in surface sediments of Barnegat Bay-Little Egg Harbor Estuary, New Jersey, USA |journal=Marine Pollution Bulletin |volume=56 |issue=10 |year=2008 |pages=1802–1808 |issn=0025-326X |doi=10.1016/j.marpolbul.2008.07.004 |pmid=18715597 |bibcode=2008MarPB..56.1802V |url=http://nora.nerc.ac.uk/id/eprint/4452/1/Vane_MPB_2008_for_NORA__2_.pdf}}</ref><ref name="VaneHarrison2009">{{cite journal |last1=Vane |first1=C.H. |last2=Harrison |first2=I. |last3=Kim |first3=A.W. |last4=Moss-Hayes |first4=V. |last5=Vickers |first5=B.P. |last6=Hong |first6=K. |title=Organic and metal contamination in surface mangrove sediments of South China |journal=Marine Pollution Bulletin |volume=58 |issue=1 |year=2009 |pages=134–144 |issn=0025-326X |doi=10.1016/j.marpolbul.2008.09.024 |pmid=18990413 |bibcode=2009MarPB..58..134V |url=http://nora.nerc.ac.uk/id/eprint/5547/1/Vane_et_al.%2C_2009.pdf}}</ref>

===Occupational exposure===
[[File:EPA workers clean up residential mercury spill (3986684199).jpg|thumb|EPA workers clean up residential mercury spill in 2004]]
Due to the health effects of mercury exposure, industrial and commercial uses are regulated in many countries. The [[Organization:World Health Organization|World Health Organization]],<ref>{{cite web|url=https://www.who.int/news-room/fact-sheets/detail/mercury-and-health|title=Mercury and health|website=World Health Organization|date=31 March 2017|access-date=22 December 2023}}</ref> [[Organization:Occupational Safety and Health Administration|OSHA]], and [[Organization:National Institute for Occupational Safety and Health|NIOSH]] all treat mercury as an occupational hazard; both OSHA and NIOSH, among other regulatory agencies, have established specific occupational exposure limits on the element and its derivative compounds in liquid and vapor form.<ref>{{cite web|url=https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TABLEZ2|publisher=Occupational Safety and Health Administration|title=1910.1000 TABLE Z-2|date=23 June 2006|access-date=22 December 2023}}</ref><ref>{{cite web|url=https://www.cdc.gov/niosh/npg/npgd0383.html|publisher=The National Institute for Occupational Safety and Health|website=Centers for Disease Control and Prevention|title=Mercury compounds [except (organo) alkyls] (as Hg)|date=30 October 2019|access-date=22 December 2023}}</ref> Environmental releases and disposal of mercury are regulated in the U.S. primarily by the United States Environmental Protection Agency.

===Fish===
{{Main|Chemistry:Mercury in fish}}
[[Biology:Fish|Fish]] and shellfish have a natural tendency to concentrate mercury in their bodies, often in the form of [[Chemistry:Methylmercury|methylmercury]], a highly toxic organic compound of mercury. Species of fish that are high on the food chain, such as [[Biology:Shark|shark]], [[Biology:Swordfish|swordfish]], [[Biology:King mackerel|king mackerel]], [[Biology:Bluefin tuna|bluefin tuna]], albacore tuna, and [[Biology:Tilefish|tilefish]] contain higher concentrations of mercury than others. Because mercury and methylmercury are fat soluble, they primarily accumulate in the viscera, although they are also found throughout the muscle tissue.<ref>{{cite journal |last1=Cocoros |first1=Glenn |last2=Cahn |first2=Phyllis H. |last3=Siler |first3=William |title=Mercury concentrations in fish, plankton and water from three Western Atlantic estuaries |journal=Journal of Fish Biology |date=November 1973 |volume=5 |issue=6 |pages=641–647 |doi=10.1111/j.1095-8649.1973.tb04500.x |bibcode=1973JFBio...5..641C }}</ref> Mercury presence in fish muscles can be studied using non-lethal muscle [[Medicine:Biopsy|biopsies]].<ref>{{Cite web|date=2015-09-30|title=How We Do Things at IISD-ELA: Collecting a fish muscle biopsy|url=https://www.iisd.org/library/how-we-do-things-iisd-ela-collecting-fish-muscle-biopsy|access-date=2020-07-07|website=IISD|language=en}}</ref> Mercury present in prey fish accumulates in the predator that consumes them. Since fish are less efficient at depurating than accumulating methylmercury, methylmercury concentrations in the fish tissue increase over time. Thus species that are high on the food chain amass body burdens of mercury that can be ten times higher than the species they consume. This process is called biomagnification. [[Medicine:Mercury poisoning|Mercury poisoning]] happened this way in Minamata, {{wipe|Japan}}, now called Minamata disease.<ref name="auto1"/><ref name="auto"/>

===Cosmetics===
Some facial creams contain dangerous levels of mercury. Most contain comparatively non-toxic inorganic mercury, but products containing highly toxic organic mercury have been encountered.<ref>{{cite web |url=https://arstechnica.com/science/2019/12/the-horrifying-case-of-organic-mercury-poisoning-from-tainted-skin-cream/ |title=Woman had 524x the normal level of mercury in her blood from skin cream use |last=Mole |first=Beth |website=ArsTechnica |date=20 December 2019 |access-date=20 July 2021}}</ref><ref>{{cite journal |url=https://www.cdc.gov/mmwr/volumes/68/wr/mm6850a4.htm |title=Notes from the Field: Methylmercury Toxicity from a Skin Lightening Cream Obtained from Mexico — California, 2019 |journal=Morbidity and Mortality Weekly Report |vauthors=Mudan, Anita, Copan L, Wang R, et al. |date=20 December 2019 |volume=68 |number=50 |pages=1166–1167 |doi=10.15585/mmwr.mm6850a4|pmid=31856147 |pmc=6936160 }}</ref> {{wipe|New York City}} residents have been found to be exposed to significant levels of inorganic mercury compounds through the use of skin care products.<ref>{{cite journal|author=McKelvey W|author2=Jeffery N|author3=Clark N|author4=Kass D|author5=Parsons PJ. 2010|title=Population-Based Inorganic Mercury Biomonitoring and the Identification of Skin Care Products as a Source of Exposure in New York City| journal=Environ Health Perspect |volume=119|issue=2|date= 2011|doi=10.1289/ehp.1002396|pages=203–9|pmid=20923743|pmc=3040607}}</ref>

===Effects and symptoms of mercury poisoning===
{{Main|Medicine:Mercury poisoning}}
Toxic effects include damage to the brain, kidneys and lungs. Mercury poisoning can result in several diseases, including [[Medicine:Acrodynia|acrodynia]] (pink disease), Hunter-Russell syndrome, and Minamata disease. 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. Case–control studies have shown effects such as tremors, impaired cognitive skills, and sleep disturbance in workers with chronic exposure to mercury vapor even at low concentrations in the range 0.7–42&nbsp;μg/m<sup>3</sup>.<ref name="ngim">{{cite journal |title=Chronic neurobehavioral effects of elemental mercury in dentists |pmid=1463679 |journal=British Journal of Industrial Medicine|volume=49 |issue=11| date=1992 |author1=Ngim, CH |author2=Foo, SC |author3=Boey, KW |author4=Keyaratnam, J |pmc=1039326 |pages=782–90 |doi=10.1136/oem.49.11.782}}</ref><ref name="liang">{{cite journal |title=Psychological effects of low exposure to mercury vapor: Application of computer-administered neurobehavioral evaluation system |journal=Environmental Research |volume=60 |issue=2| doi=10.1006/enrs.1993.1040 |date=1993 |pmid=8472661 |last1=Liang |first1=Y. X. |last2=Sun |first2=R. K. |last3=Sun |first3=Y. |last4=Chen |first4=Z. Q. |last5=Li |first5=L. H. |bibcode=1993ER.....60..320L |pages=320–7}}</ref> 

A study has shown that acute exposure (4–8 hours) to calculated elemental mercury levels of 1.1 to 44&nbsp;mg/m<sup>3</sup> resulted in chest pain, dyspnea, cough, [[Medicine:Hemoptysis|hemoptysis]], impairment of pulmonary function, and evidence of interstitial [[Medicine:Pneumonitis|pneumonitis]].<ref name="acutepoisoning" /> Acute exposure to mercury vapor has been shown to result in profound central nervous system effects, including psychotic reactions characterized by delirium, hallucinations, and suicidal tendency. Occupational exposure has resulted in broad-ranging functional disturbance, including [[Medicine:Erethism|erethism]], irritability, excitability, excessive shyness, and insomnia. With continuing exposure, a fine tremor develops and may escalate to violent muscular spasms. Tremor initially involves the hands and later spreads to the eyelids, lips, and tongue. Long-term, low-level exposure has been associated with more subtle symptoms of erethism, including fatigue, irritability, loss of memory, vivid dreams and depression.<ref name="chronicpoisoning" /><ref>{{EHC-ref |id=118 |name=Inorganic mercury |date=1991 |isbn=92-4-157118-7}}</ref>

===Treatment===
Research on the treatment of mercury poisoning is limited. Currently available drugs for acute mercurial poisoning include chelators N-acetyl-D, L-[[Chemistry:Penicillamine|penicillamine]] (NAP), British Anti-Lewisite (BAL), 2,3-dimercapto-1-propanesulfonic acid (DMPS), and [[Chemistry:Dimercaptosuccinic acid|dimercaptosuccinic acid]] (DMSA). In one small study including 11 construction workers exposed to elemental mercury, patients were treated with DMSA and NAP.<ref name=Bluhm>{{cite journal|last1=Bluhm |first1=RE |journal=Hum Exp Toxicol |date=1992 |volume=11 |issue=3 |title=Elemental Mercury Vapour Toxicity, Treatment, and Prognosis After Acute, Intensive Exposure in Chloralkali Plant Workers. Part I: History, Neuropsychological Findings and Chelator effects |last2=Bobbitt |first2=RG |last3=Welch |first3=LW |last4=Wood |first4=AJJ |last5=Bonfiglio |first5=JF |last6=Sarzen |first6=C |last7=Heath |first7=AJ |last8=Branch |first8=RA |pages=201–10 |pmid=1352115 |doi=10.1177/096032719201100308 |bibcode=1992HETox..11..201B |s2cid=43524794}}</ref> [[Unsolved:Chelation therapy|Chelation therapy]] with both drugs resulted in the mobilization of a small fraction of the total estimated body mercury. DMSA was able to increase the excretion of mercury to a greater extent than NAP.<ref name=Bluhm/>

==Regulations==

===International===
140 countries agreed in the Minamata Convention on Mercury by the [[Organization:United Nations Environment Programme|United Nations Environment Programme]] (UNEP) to prevent mercury vapor emissions.<ref>{{cite web |url=http://www.unep.org/newscentre/Default.aspx?DocumentID=2702&ArticleID=9373&l=en |title=Minamata Convention Agreed by Nations |publisher=United Nations Environment Program |access-date=19 January 2013 |url-status=live |archive-url=https://web.archive.org/web/20130130192928/http://www.unep.org/NewsCentre/default.aspx?DocumentID=2702&ArticleID=9373&l=en |archive-date=30 January 2013}}</ref> The convention was signed on 10 October 2013.<ref>{{Cite web|url=https://www.un.org/apps/news/story.asp?NewsID=43963&Cr=mercury&Cr1=#.UPt4ikfdP5M|title=UN News&nbsp;— Governments at UN forum agree on legally-binding treaty to curb mercury pollution|last=Section|first=United Nations News Service|date=19 January 2013|website=UN News Service Section|access-date=22 November 2016|url-status=live|archive-url=https://web.archive.org/web/20161016131029/http://www.un.org/apps/news/story.asp?NewsID=43963&Cr=mercury&Cr1=#.UPt4ikfdP5M|archive-date=16 October 2016}}</ref>

===United States===
In the United States, the Environmental Protection Agency is charged with regulating and managing mercury contamination. Several laws give the EPA this authority, including the Clean Air Act, the Clean Water Act, the [[Social:Resource Conservation and Recovery Act|Resource Conservation and Recovery Act]], and the Safe Drinking Water Act. Additionally, the Mercury-Containing and Rechargeable Battery Management Act, passed in 1996, phases out the use of mercury in batteries, and provides for the efficient and cost-effective disposal of many types of used batteries.<ref name="epa regs">{{cite web |url=http://www.epa.gov/mercury/regs.htm |title=Mercury: Laws and regulations|date=16 April 2008|publisher=United States Environmental Protection Agency|access-date=30 May 2008 |url-status=live|archive-url=https://web.archive.org/web/20080513123415/http://epa.gov/mercury/regs.htm|archive-date=13 May 2008}}</ref> North America contributed approximately 11% of the total global anthropogenic mercury emissions in 1995.<ref>{{cite web |url=http://www.ijc.org/php/publications/html/12br/english/report/chemical/rme.html|title=Reductions in Mercury Emissions|publisher=[[Organization:International Joint Commission|International Joint Commission]] on the Great Lakes |archive-url=https://web.archive.org/web/20080828060223/http://www.ijc.org/php/publications/html/12br/english/report/chemical/rme.html|archive-date=28 August 2008|access-date=21 July 2008}}</ref>

The United States Clean Air Act, passed in 1990, put mercury on a list of toxic pollutants that need to be controlled to the greatest possible extent. Thus, industries that release high concentrations of mercury into the environment agreed to install maximum achievable control technologies (MACT). In March 2005, the EPA promulgated a regulation<ref>{{cite web |url=http://www.epa.gov/air/mercuryrule/|title=Clean Air Mercury Rule|publisher=United States Environmental Protection Agency (EPA)|access-date=1 May 2007|url-status=live|archive-url=https://web.archive.org/web/20070630045554/http://www.epa.gov/air/mercuryrule/|archive-date=30 June 2007}}</ref> that added power plants to the list of sources that should be controlled and instituted a national [[Earth:Emissions trading|cap and trade]] system. States were given until November 2006 to impose stricter controls, but after a legal challenge from several states, the regulations were struck down by a federal appeals court on 8 February 2008. The rule was deemed not sufficient to protect the health of persons living near coal-fired power plants, given the negative effects documented in the EPA Study Report to Congress of 1998.<ref name="nj vs epa">{{cite news|url=http://pacer.cadc.uscourts.gov/docs/common/opinions/200802/05-1097a.pdf|title=State of New Jersey et al., Petitioners vs. Environmental Protection Agency (Case No. 05-1097)|publisher=United States Court of Appeals for the District of Columbia Circuit. Argued 6 December 2007, Decided 8 February 2008|access-date=30 May 2008|url-status=live|archive-url=https://web.archive.org/web/20110203021258/http://pacer.cadc.uscourts.gov/docs/common/opinions/200802/05-1097a.pdf|archive-date=3 February 2011}}</ref> However newer data published in 2015 showed that after introduction of the stricter controls mercury declined sharply, indicating that the Clean Air Act had its intended impact.<ref>{{cite journal |vauthors=Castro MS, Sherwell J |year=2015 |title=Effectiveness of Emission Controls to Reduce the Atmospheric Concentrations of Mercury |journal=Environmental Science & Technology |volume=49 |issue=24| pages=14000–14007 |doi=10.1021/acs.est.5b03576 |pmid=26606506 |bibcode=2015EnST...4914000C}}</ref>

The EPA announced new rules for coal-fired power plants on 22 December 2011.<ref>{{cite news |url=https://www.bostonglobe.com/news/nation/2011/12/22/oldest-dirtiest-power-plants-told-clean/mORfVS1jUOOlXuTPIRQKbL/story.html |title=Oldest, dirtiest power plants told to clean up|date=22 December 2011|newspaper=Boston Globe|access-date=2 January 2012|url-status=live|archive-url=https://web.archive.org/web/20140714151501/http://www.bostonglobe.com/news/nation/2011/12/22/oldest-dirtiest-power-plants-told-clean/mORfVS1jUOOlXuTPIRQKbL/story.html|archive-date=14 July 2014}}</ref> Cement kilns that burn hazardous waste are held to a looser standard than are standard hazardous waste incinerators in the United States, and as a result are a disproportionate source of mercury pollution.<ref>{{cite news|url=https://www.npr.org/2011/11/10/142183546/epa-regulations-give-kilns-permission-to-pollute|title=EPA Regulations Give Kilns Permission To Pollute|author=Howard Berkes|agency=NPR|date=10 November 2011|access-date=2 January 2012|url-status=live|archive-url=https://web.archive.org/web/20111117112612/http://www.npr.org/2011/11/10/142183546/epa-regulations-give-kilns-permission-to-pollute |archive-date=17 November 2011}}</ref>

===European Union===
In the [[Social:European Union|European Union]], the directive on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment (see [[Chemistry:Restriction of Hazardous Substances Directive|RoHS]]) bans mercury from certain electrical and electronic products, and limits the amount of mercury in other products to less than 1000 [[Parts per million|ppm]].<ref name="eu regs">{{cite web|url=http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2003:037:0019:0023:EN:PDF |title=Directive 2002/95/EC on the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment|date=27 January 2003}} Article 4 Paragraph 1. e.g. "Member States shall ensure that, from July 1, 2006, new electrical and electronic equipment put on the market does not contain lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) or polybrominated diphenyl ethers (PBDE)."</ref> There are restrictions for mercury concentration in packaging (the limit is 100 ppm for sum of mercury, [[Chemistry:Lead|lead]], [[Chemistry:Hexavalent chromium|hexavalent chromium]] and [[Chemistry:Cadmium|cadmium]]) and batteries (the limit is 5 ppm).<ref>{{cite web|url=http://www.eiatrack.org/s/1785|title=Mercury compounds in European Union|date=2007|publisher=EIA Track|access-date=30 May 2008|archive-url=https://web.archive.org/web/20080428065154/http://www.eiatrack.org/s/1785|archive-date=28 April 2008}}</ref> In July 2007, the European Union also banned mercury in non-electrical measuring devices, such as [[Physics:Thermometer|thermometer]]s and [[Engineering:Barometer|barometer]]s. The ban applies to new devices only, and contains exemptions for the health care sector and a two-year grace period for manufacturers of barometers.<ref name="eu reuters">{{cite news|url=https://www.reuters.com/article/environmentNews/idUSL0988544920070710|title=EU bans mercury in barometers, thermometers|author=Jones H.|date=10 July 2007|publisher=Reuters|access-date=12 September 2017|url-status=live|archive-url=https://web.archive.org/web/20090103193545/http://www.reuters.com/article/environmentNews/idUSL0988544920070710|archive-date=3 January 2009}}</ref> 

===Scandinavia===
{{wipe|Norway}} enacted a total ban on the use of mercury in the manufacturing and import/export of mercury products, effective 1 January 2008.<ref name="norway">{{cite news |url=http://www.eubusiness.com/news-eu/1198237627.85 |title=Norway to ban mercury|date=21 December 2007|publisher=EU Business|access-date=30 May 2008 |archive-url = https://web.archive.org/web/20080121173517/http://www.eubusiness.com/news-eu/1198237627.85 |archive-date = 21 January 2008}}</ref> In 2002, several lakes in Norway were found to have a poor state of mercury pollution, with an excess of 1&nbsp;μg/g of mercury in their sediment.<ref name="environment norway">{{cite journal |doi=10.1016/j.scitotenv.2005.09.059 |date=2006 |title=Atmospheric mercury in Norway: contributions from different sources |volume=368 |issue=1 |pages=3–9 |pmid=16310836 |journal=The Science of the Total Environment|author1=Berg, T |author2=Fjeld, E |author3=Steinnes, E |bibcode=2006ScTEn.368....3B}}</ref> In 2008, Norway's Minister of Environment Development Erik Solheim said: "Mercury is among the most dangerous environmental toxins. Satisfactory alternatives to Hg in products are available, and it is therefore fitting to induce a ban."<ref>{{cite report |last1=Edlich |first1=Richard F |last2=Rhoads |first2=Samantha K. |last3=Cantrell |first3=Holly S. |last4=Azavedo |first4=Sabrina M. |last5=Newkirk |first5=Anthony T. |title=Banning Mercury Amalgam in the United States |location=USA |publisher=[[Organization:Food and Drug Administration|Food and Drug Administration]] |url=https://www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials/medicaldevices/medicaldevicesadvisorycommittee/dentalproductspanel/ucm236379.pdf |archive-url=https://web.archive.org/web/20131101215237/https://www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials/medicaldevices/medicaldevicesadvisorycommittee/dentalproductspanel/ucm236379.pdf |archive-date=1 November 2013}}</ref> Products containing mercury were banned in Sweden in 2009,<ref>{{Cite web|url=http://www.thelocal.se/20090114/16892 |title=Sweden to ban mercury |work=The Local |date=14 January 2009 |access-date=22 November 2016 |url-status=live |archive-url=https://web.archive.org/web/20160828040807/http://www.thelocal.se/20090114/16892 |archive-date=28 August 2016}}</ref><ref>{{Cite web |url=http://www.thelocal.se/20120421/40396 |title=Sweden may be forced to lift ban on mercury |work=The Local |date=21 April 2012 |access-date=22 November 2016 |url-status=live |archive-url=https://web.archive.org/web/20160828101154/http://www.thelocal.se/20120421/40396 |archive-date=28 August 2016}}</ref> while elemental mercury has been banned from manufacture and use in all but a few applications (such as certain energy-saving light sources and amalgam dental fillings) in Denmark since 2008.<ref>{{cite web|url=https://www2.mst.dk/Udgiv/publications/2014/01/978-87-93026-98-8.pdf|title=Survey of mercury and mercury compounds |website=Miljøstyrelsen |date=2014|access-date=21 December 2023}}</ref>

==See also==
* [[Earth:Mercury pollution in the ocean|Mercury pollution in the ocean]]
* [[Chemistry:Red mercury|Red mercury]]
* [[Physics:COLEX process|COLEX process]] (isotopic separation)

== References ==

{{reflist | colwidth=30em | refs =

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{{cite book
 | url                = http://nora.nerc.ac.uk/id/eprint/8224/1/WMP2001-2005.pdf
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 | author-first       = L. E.
 | author-last2       = Brown
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 | author-last4       = Lusty
 | author-first4      = P. A. J.
 | author-last5       = Idoine
 | author-first5      = N. E.
 | date               = 2007
 | title              = World mineral production: 2001–05
 | location           = Keyworth, Nottingham, UK
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 | access-date        = 2019-02-20
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==Further reading==
*{{Cite book |last=Johnston |first=Andrew Scott |url=https://books.google.com/books?id=_ZK-AwAAQBAJ |title=Mercury and the Making of California: Mining, Landscape, and Race, 1840–1890 |date=15 September 2013 |publisher=University Press of Colorado |others=TotalBoox, TBX |isbn=978-1-4571-8399-7 |oclc=969039240}}

==External links==
{{commons}}
* [http://www.rsc.org/chemistryworld/podcast/element.asp Chemistry in its element podcast] (MP3) from the [[Organization:Royal Society of Chemistry|Royal Society of Chemistry]]'s Chemistry World: [http://www.rsc.org/images/CIIE_Mercury_48kbps_tcm18-133983.mp3 Mercury]
* [http://www.periodicvideos.com/videos/080.htm Mercury] at ''The Periodic Table of Videos'' (University of Nottingham)
* [https://www.cdc.gov/niosh/topics/mercury/ Centers for Disease Control and Prevention&nbsp;– Mercury Topic]
* [http://www.epa.gov/ostwater/fishadvice/advice.html EPA fish consumption guidelines]
* [http://www.theodoregray.com/PeriodicTable/Elements/080/index.s7.html Hg 80 Mercury]
* [https://www.inchem.org/documents/icsc/icsc/eics0056.htm Material Safety Data Sheet – Mercury ICSC 0056]
* [http://eu.oceana.org/en/our-work/mercury/overview Stopping Pollution: Mercury] – Oceana
* [http://www.nrdc.org/health/effects/mercury/index.asp Natural Resources Defense Council (NRDC): Mercury Contamination in Fish guide] – NRDC
* [http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@rn+@rel+7439-97-6 NLM Hazardous Substances Databank – Mercury]
* [http://news.bbc.co.uk/earth/hi/earth_news/newsid_9243000/9243902.stm BBC – Earth News – Mercury "turns" wetland birds such as ibises homosexual]
* [https://purl.fdlp.gov/GPO/gpo41802 Changing Patterns in the Use, Recycling, and Material Substitution of Mercury in the United States] United States Geological Survey
* [http://www.impmc.jussieu.fr/%7Eayrinhac/documents/Hg_data.pdf Thermodynamical data on liquid mercury.]

{{Periodic table (navbox)}}
{{Mercury compounds}}

{{DEFAULTSORT:Mercury}}
[[Category:Mercury (element)| ]]
[[Category:Chemical elements]]
[[Category:Coolants]]
[[Category:Endocrine disruptors]]
[[Category:Native element minerals]]
[[Category:Neurotoxins]]
[[Category:Nuclear reactor coolants]]
[[Category:Transition metals]]

{{Sourceattribution|Mercury (element)}}