Fluorine cycle: Difference between revisions

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Fluorine cycle: F fluxes^[1] are in Tg/yr and reservoir data^[2] is in mg/kg. The major mechanisms that mobilize fluorine are chemical and mechanical weathering of rocks. Major anthropogenic sources also include industrial chemicals and fertilizers, brick manufacturing, and groundwater extraction. Fluorine is primarily carried by rivers to the oceans, where it can have a residence time of about 500,000 years. Fluorine can be removed from the ocean by deposition of terrigenous or authigenic sediments, or subduction of the oceanic lithosphere.

The fluorine cycle is the series of biogeochemical processes through which fluorine moves through the lithosphere, hydrosphere, atmosphere, and biosphere. Fluorine originates from the Earth’s crust, and its cycling between various sources and sinks is modulated by a variety of natural and anthropogenic processes.

Overview

Fluorine is the thirteenth most abundant element on Earth and the 24th most abundant element in the universe. It is the most electronegative element and it is highly reactive. Thus, it is rarely found in its elemental state, although elemental fluorine has been identified in certain geochemical contexts.^[3] Instead, it is most frequently found in ionic compounds (e.g. HF, CaF₂).

The major mechanisms that mobilize fluorine are chemical and mechanical weathering of rocks. Major anthropogenic sources include industrial chemicals and fertilizers, brick manufacturing, and groundwater extraction. Fluorine is primarily carried by rivers to the oceans, where it has a residence time of about 500,000 years. Fluorine can be removed from the ocean by deposition of terrigenous or authigenic sediments, or subduction of the oceanic lithosphere.

Lithosphere

The vast majority of the Earth's fluorine is found in the crust, where it is primarily found in hydroxysilicate minerals.^[3] Levels of fluorine in igneous rocks vary greatly, and are influenced by the fluorine contents of magma. Likewise, altered oceanic crust exhibits large variability in fluorine; serpentinization zones contain elevated levels of fluorine.^[4] Many details concerning the exact mineralogy and distribution of fluorine in the crust are poorly understood, particularly fluorine's abundance in metamorphic rocks, in the mantle, and in the core.^[1]

Fluorine can be liberated from its crustal reservoirs via natural processes (such as weathering, erosion, and volcanic activity) or anthropogenic processes, such as phosphate rock processing, coal combustion, and brick-making. Anthropogenic contributions to the fluorine cycle are significant, with anthropogenic emissions contributing about 55% of global fluorine inputs.^[1]

Hydrosphere

Fluorine can dissolve into waters as the anion fluoride, where is abundance depends on local abundance within the surrounding rocks. This is in contrast to other halogen abundances, which tend to reflect the abundance of other local halogens, rather than the local rock composition.^[4] Dissolved fluoride is present found in low abundances in surface runoff in rainwater and rivers, and higher concentrations (74 micromolar) in seawater. Fluorine can also enter surface waters via volcanic plumes.^[4]

Atmosphere

Fluorine can enter the atmosphere via volcanic activity and other geothermal emissions,^[5] as well as via biomass burning and wind-blown dust plumes.^[3] Additionally, it can come from a wide variety of anthropogenic sources, including coal combustion, brick-making, uranium processing, chemical manufacturing, aluminum production, glass etching, and the microelectronics/semiconductor industry. Fluorine can also enter the atmosphere as a product of reactions between anthropogenically-generated atmospheric chemicals (for example, uranium fluoride).^[5] Furthermore, fluorine is a component in chlorofluorocarbon gases (CFCs), which were mass-produced throughout the 20th century until the detrimental effects associated with their breakdown into highly reactive chlorine and chlorine oxide species were better understood.^[6] The majority of contemporary studies on atmospheric fluorine focus on hydrogen fluoride (HF) in the troposphere, due to HF gas’s toxicity and high reactivity.^[5]

Fluorine can be removed from the atmosphere via “wet” deposition, by precipitating out of rain, dew, fog, or cloud droplets, or via “dry” deposition, which refers to any processes that do not involve liquid water, such as adherence to surface materials as driven by atmospheric turbulence. HF can also be removed from the atmosphere via photochemical reactions in the stratosphere.^[5]

Biosphere

Fluorine is an important element for biological systems. From a mammalian health perspective, it is notable as a component of fluorapatite, a key mineral in the teeth of humans that have been exposed to fluorine, as well as shark and fish teeth.^[4] In soil, fluorine can act as a source for biological systems and a sink for atmospheric processes, as atmospheric fluorine can leach to considerable depths.^[3]

References

^ ^a ^b ^c Schlesinger, W.H.; Klein, E.M.; Vengosh, A. (2020). "Global Biogeochemical Cycle of Fluorine". Global Biogeochemical Cycles. 34 (12): e06722. Bibcode:2020GBioC..3406722S. doi:10.1029/2020gb006722. ISSN 0886-6236. S2CID 226336384.
^ Rudnick, R.L.; Gao, S. (2003), "Composition of the Continental Crust", Treatise on Geochemistry, 3, Elsevier: 659, Bibcode:2003TrGeo...3....1R, doi:10.1016/b0-08-043751-6/03016-4, ISBN 978-0-08-043751-4
^ ^a ^b ^c ^d Fuge, R. (2019). "Fluorine in the environment, a review of its sources and geochemistry". Applied Geochemistry. 100: 393–406. Bibcode:2019ApGC..100..393F. doi:10.1016/j.apgeochem.2018.12.016. S2CID 133909303.
^ ^a ^b ^c ^d Koga, K.T.; Rose-Koga, E.F. (2018). "Fluorine in the Earth and the solar system, where does it come from and can it be found?". Comptes Rendus Chimie. 21 (8): 749–756. doi:10.1016/j.crci.2018.02.002.
^ ^a ^b ^c ^d Cheng, M.-D. (2018). "Atmospheric chemistry of hydrogen fluoride". Journal of Atmospheric Chemistry. 75 (1): 1–16. Bibcode:2018JAtC...75....1C. doi:10.1007/s10874-017-9359-7. ISSN 1573-0662. OSTI 1399939. S2CID 100201001.
^ Crutzen, P.J. (2006). "Introduction to "Fluorine and the Environment"". Advances in Fluorine Science. 1: xv–xvii. doi:10.1016/S1872-0358(06)01011-6. ISBN 9780444528117. ISSN 1872-0358.

[:0-1] Schlesinger, W.H.; Klein, E.M.; Vengosh, A. (2020). "Global Biogeochemical Cycle of Fluorine". Global Biogeochemical Cycles. 34 (12): e06722. Bibcode:2020GBioC..3406722S. doi:10.1029/2020gb006722. ISSN 0886-6236. S2CID 226336384.

[:4-2] Rudnick, R.L.; Gao, S. (2003), "Composition of the Continental Crust", Treatise on Geochemistry, 3, Elsevier: 659, Bibcode:2003TrGeo...3....1R, doi:10.1016/b0-08-043751-6/03016-4, ISBN 978-0-08-043751-4

[:1-3] Fuge, R. (2019). "Fluorine in the environment, a review of its sources and geochemistry". Applied Geochemistry. 100: 393–406. Bibcode:2019ApGC..100..393F. doi:10.1016/j.apgeochem.2018.12.016. S2CID 133909303.

[:2-4] Koga, K.T.; Rose-Koga, E.F. (2018). "Fluorine in the Earth and the solar system, where does it come from and can it be found?". Comptes Rendus Chimie. 21 (8): 749–756. doi:10.1016/j.crci.2018.02.002.

[:3-5] Cheng, M.-D. (2018). "Atmospheric chemistry of hydrogen fluoride". Journal of Atmospheric Chemistry. 75 (1): 1–16. Bibcode:2018JAtC...75....1C. doi:10.1007/s10874-017-9359-7. ISSN 1573-0662. OSTI 1399939. S2CID 100201001.

[6] Crutzen, P.J. (2006). "Introduction to "Fluorine and the Environment"". Advances in Fluorine Science. 1: xv–xvii. doi:10.1016/S1872-0358(06)01011-6. ISBN 9780444528117. ISSN 1872-0358.

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@@ Line 1: / Line 1: @@
+{{Short description|Biogeochemical cycle}}
-{{dashboard.wikiedu.org sandbox}}
+[[File:FluorineCycleWikiMcKaig.png|thumb|upright=2|Fluorine cycle: F fluxes<ref name=":0" /> are in Tg/yr and reservoir data<ref name=":4">{{Citation|last1=Rudnick|first1=R.L.|title=Composition of the Continental Crust|date=2003 | url=https://linkinghub.elsevier.com/retrieve/pii/B0080437516030164| journal=Treatise on Geochemistry| volume=3| page=659| publisher=Elsevier| language=en| bibcode=2003TrGeo...3....1R| doi=10.1016/b0-08-043751-6/03016-4| isbn=978-0-08-043751-4| access-date=| last2=Gao| first2=S.}}</ref> is in mg/kg. The major mechanisms that mobilize fluorine are chemical and mechanical weathering of rocks. Major anthropogenic sources also include industrial chemicals and fertilizers, brick manufacturing, and groundwater extraction. Fluorine is primarily carried by rivers to the oceans, where it can have a residence time of about 500,000 years. Fluorine can be removed from the ocean by deposition of terrigenous or authigenic sediments, or subduction of the oceanic lithosphere.]]
+The '''fluorine cycle''' is the series of biogeochemical processes through which [[fluorine]] moves through the [[lithosphere]], [[hydrosphere]], [[atmosphere]], and [[biosphere]]. Fluorine originates from the Earth’s crust, and its cycling between various sources and sinks is modulated by a variety of natural and anthropogenic processes.
-==Fluorine Cycle==
-The fluorine (F) cycle is the series of biogeochemical processes through which fluorine moves through the lithosphere, hydrosphere, atmosphere, and biosphere.
+==Overview==
-Fluorine is the 13th most abundant element on Earth and the 24th most abundant element in the universe. It the most electronegative element and it is highly reactive. Thus, it is rarely found in its elemental state (although elemental fluorine has been identified in certain geochemical contexts)<ref> Fuge, R. (2019) Fluorine in the environment, a review of its sources and geochemistry. ''Applied Geochemistry''. DOI: 10.1016/j.apgeochem.2018.12.016 </ref>.' Fluorine can be liberated from its crustal reservoirs via natural processes (such as weathering, erosion, and volcanic activity) or anthropogenic processes, such as phosphate rock processing, coal combustion, and brick-making. Anthropogenic contributions to the fluorine cycle are highly prominent, with anthropogenic emissions contributing about 55% of total F inputs<ref> Schlesinger, W.H., Klein, E.M. (2020) Global Biogeochemical Cycle of Fluorine. ''American Geophysical Union''. DOI: 10.1029/2020GB006722 </ref>.
+Fluorine is the thirteenth most abundant element on Earth and the 24th most abundant element in the universe. It is the most electronegative element and it is highly reactive. Thus, it is rarely found in its elemental state, although elemental fluorine has been identified in certain geochemical contexts.<ref name=":1">{{Cite journal|last=Fuge|first=R.|date=2019|title=Fluorine in the environment, a review of its sources and geochemistry|url=https://linkinghub.elsevier.com/retrieve/pii/S0883292718303676|journal=Applied Geochemistry|language=en|volume=100|pages=393–406|doi=10.1016/j.apgeochem.2018.12.016|bibcode=2019ApGC..100..393F|s2cid=133909303}}</ref> Instead, it is most frequently found in ionic compounds (e.g. HF, CaF<sub>2</sub>).
+The major mechanisms that mobilize fluorine are chemical and mechanical [[weathering]] of rocks. Major anthropogenic sources include industrial chemicals and fertilizers, brick manufacturing, and groundwater extraction. Fluorine is primarily carried by rivers to the oceans, where it has a residence time of about 500,000 years. Fluorine can be removed from the ocean by deposition of terrigenous or [[Authigenesis|authigenic]] sediments, or [[subduction]] of the oceanic lithosphere.
-The vast majority of the Earth's fluorine is found in the crust, where it is primarily found in hydroxysilicate minerals<ref> Fuge, R. (2019) Fluorine in the environment, a review of its sources and geochemistry. ''Applied Geochemistry''. DOI: 10.1016/j.apgeochem.2018.12.016 </ref>. However, other details concerning the exact mineralogy and distribution of fluorine in the crust are poorly understood, particularly F's abundance in metamorphic rocks and in the mantle. Additionally, fluorine transfer between surface waters and crustal rocks is not well-constrained<ref> Koga, K.T., Rose-Koga, E.F (2018) Fluorine in the Earth and the solar system, where does it come from and can it be found? ''Comptes Rendus Chimie''. DOI: 10.1016/j.crci.2018.02.002 </ref>.'
+== Lithosphere ==
-How does fluorine move?
+{{biogeochemical cycle sidebar|other}}
+The vast majority of the Earth's fluorine is found in the [[Crust (geology)|crust]], where it is primarily found in hydroxysilicate minerals.<ref name=":1" /> Levels of fluorine in [[Igneous rock|igneous rocks]] vary greatly, and are influenced by the  fluorine contents of magma. Likewise, altered [[oceanic crust]] exhibits large variability in fluorine; [[serpentinization]] zones contain elevated levels of fluorine.<ref name=":2">{{Cite journal|last1=Koga|first1=K.T.|last2=Rose-Koga|first2=E.F.|date=2018|title=Fluorine in the Earth and the solar system, where does it come from and can it be found?|journal=Comptes Rendus Chimie|language=en|volume=21|issue=8|pages=749–756|doi=10.1016/j.crci.2018.02.002|doi-access=free}}</ref> Many details concerning the exact mineralogy and distribution of fluorine in the crust are poorly understood, particularly fluorine's abundance in [[Metamorphic rock|metamorphic rocks]], in the mantle, and in the core.<ref name=":0">{{Cite journal|last1=Schlesinger|first1=W.H.|last2=Klein|first2=E.M.|last3=Vengosh|first3=A.|date=2020|title=Global Biogeochemical Cycle of Fluorine|url=http://dx.doi.org/10.1029/2020gb006722|journal=Global Biogeochemical Cycles|volume=34|issue=12|pages=e06722|doi=10.1029/2020gb006722|bibcode=2020GBioC..3406722S|s2cid=226336384|issn=0886-6236}}</ref>
-what is fluorine important for?
+Fluorine can be liberated from its crustal reservoirs via natural processes (such as [[weathering]], [[erosion]], and [[volcanic activity]]) or anthropogenic processes, such as phosphate rock processing, coal combustion, and [[brick-making]]. Anthropogenic contributions to the fluorine cycle are significant, with anthropogenic emissions contributing about 55% of global fluorine inputs.<ref name=":0" />
-[[File:Fluorine cycle draft2.png|thumb|Fluorine cycle: F fluxes<ref> Schlesinger, W.H., Klein, E.M. (2020) Global Biogeochemical Cycle of Fluorine. ''American Geophysical Union''. DOI: 10.1029/2020GB006722 </ref> are in Tg/yr,
-reservoir data<ref> Rudnick, R.L. and Gao, S. (2014) Composition of the continental crust. ''Treatise on Geochemistry: 2nd Edition''. DOI: 10.1016/B0-08-043751-6/03016-4 </ref> is in mg/kg. The major mechanisms that mobilize fluorine are chemical and mechanical weathering of rocks. Major anthropogenic sources also include industrial chemicals and fertilizers, brick manufacturing, and groundwater extraction. Fluorine is primarily carried by rivers to the oceans, where it can have a residence time of about 500,000 years. Fluorine can be removed from the ocean by deposition of terrigenous or authigenic sediments, or subduction of the oceanic lithosphere.]]
-== Article Evaluation ==
+== Hydrosphere ==
+Fluorine can dissolve into waters as the anion [[fluoride]], where is abundance depends on local abundance within the surrounding rocks. This is in contrast to other [[halogen]] abundances, which tend to reflect the abundance of other local halogens, rather than the local rock composition.<ref name=":2" /> Dissolved [[fluoride]] is present found in low abundances in [[surface runoff]] in rainwater and rivers, and higher concentrations (74 [[micromolar]]) in seawater. Fluorine can also enter surface waters via volcanic plumes.<ref name=":2" />
-=== Oxygen Cycle ===
-==== Content ====
-Overall, this article contains lots of useful information about the oxygen cycle, and is corroborated by many references. The majority of the sources were published within the last 20 years, and the important information generally appears up to date. Complex concepts are explained well. A wide variety of related topics are linked to their respective Wikipedia articles (e.g. biogeochemical transitions, silicate minerals, and the Great Oxygenation Event). This article could be improved by adding more general details: for example, the relationship between atmospheric oxygen and ozone is briefly mentioned, but more discussion of the impacts of ozone depletion could be interesting. Additionally, there are some instances of poor sentence structure, grammatical errors, and run-on sentences, which sometimes impact readability.
-==== Tone ====
+== Atmosphere ==
+Fluorine can enter the atmosphere via volcanic activity and other geothermal emissions,<ref name=":3">{{Cite journal|last=Cheng|first=M.-D.|date=2018|title=Atmospheric chemistry of hydrogen fluoride|url=https://doi.org/10.1007/s10874-017-9359-7|journal=Journal of Atmospheric Chemistry|language=en|volume=75|issue=1|pages=1–16|doi=10.1007/s10874-017-9359-7|bibcode=2018JAtC...75....1C|osti=1399939|s2cid=100201001|issn=1573-0662}}</ref> as well as via biomass burning and wind-blown dust plumes.<ref name=":1" /> Additionally, it can come from a wide variety of anthropogenic sources, including coal combustion, brick-making, uranium processing, chemical manufacturing, aluminum production, glass etching, and the microelectronics/[[semiconductor]] industry. Fluorine can also enter the atmosphere as a product of reactions between anthropogenically-generated atmospheric chemicals (for example, [[uranium fluoride]]).<ref name=":3" /> Furthermore, fluorine is a component in [[chlorofluorocarbon]] gases (CFCs), which were mass-produced throughout the 20th century until the detrimental effects associated with their breakdown into highly reactive [[chlorine]] and [[chlorine oxide]] species were better understood.<ref>{{Cite journal|last=Crutzen|first=P.J.|date=2006|title=Introduction to "Fluorine and the Environment"|url=https://www.sciencedirect.com/science/article/pii/S1872035806010116|journal=Advances in Fluorine Science|language=en|volume=1|pages=xv–xvii|doi=10.1016/S1872-0358(06)01011-6|isbn=9780444528117|issn=1872-0358}}</ref> The majority of contemporary studies on atmospheric fluorine focus on hydrogen fluoride (HF) in the troposphere, due to HF gas’s toxicity and high reactivity.<ref name=":3" />
-Overall, the article has a neutral, unbiased tone. However, there is a claim in the "Capacities and fluxes" section that many organizations misrepresent the level of oceanic oxygen production. The only information supporting this claim comes from a single source that is over 40 years old.
+Fluorine can be removed from the atmosphere via “wet” deposition, by precipitating out of rain, dew, fog, or cloud droplets, or via “dry” deposition, which refers to any processes that do not involve liquid water, such as adherence to surface materials as driven by atmospheric turbulence. HF can also be removed from the atmosphere via [[Photochemistry|photochemical]] reactions in the [[stratosphere]].<ref name=":3" />
-==== Sources ====
-The checked citations all worked, and the sources generally support the claims made in the article. However, there are many instances where facts are not backed up by referenced sources (notably the sections on sources/sinks and ozone). Most of the cited sources are from reputable scientific journals, so the articles have been subjected to peer-review processes and are presumably reasonably neutral and well-founded. However, this also means that most of these pieces are behind paywalls, so readers without subscription services or institutional access will not be able to access the full texts of many of these sources.
-==== Figure ====
+== Biosphere ==
+Fluorine is an important element for biological systems. From a mammalian health perspective, it is notable as a component of [[fluorapatite]], a key mineral in the teeth of humans that have been exposed to fluorine, as well as shark and fish teeth.<ref name=":2" /> In soil, fluorine can act as a source for biological systems and a sink for atmospheric processes, as atmospheric fluorine can leach to considerable depths.<ref name=":1" />
-The figure is visually interesting, well-designed, and high resolution. The arrows portray the flow of oxygen between the atmosphere and the the terrestrial biosphere, marine biosphere, and lithosphere. However, the depiction of the loss of hydrogen gas from space and its relevance to the oxygen cycle is confusing.
+== References ==
+<references />
-=== Selenium Cycle ===
-==== Content ====
-Everything included in this article is relevant to the selenium cycle; however, there are many areas that could use additional development. For example, the introduction states that selenium can be metabolized by a wide variety of bacteria, fungi, and plant species, and an example of a terrestrial plant is provided. However, the only sub-topic of the article focuses on selenium cycling in aquatic systems. The article only cites 3 sources, the newest of which was published in 1999. More sources overall, and more recent sources, should be incorporated into this article. Complex ideas are generally explained well, but there are some instances of jargon (e.g. seleniferous soils, valence, benthic invertebrates) that would benefit from further explanation. Additionally, the article does link to some other Wikipedia articles, but there are definitely other topics that could be linked to their respective articles.
-==== Tone ====
-The tone of the article is neutral, and no heavily biased claims are made. Viewpoints from the environmental sustainability community are missing, which is especially conspicuous because two of the three cited sources focus on the detrimental role of selenium as a bioaccumulating contaminant, which is not mentioned in the article.
+[[Category:Fluorine]]
-==== Sources ====
+[[Category:Biogeochemical cycle]]
-All of the links work, and the cited facts generally do appear in the original sources. The sources come from scientific journals and government reports, so are likely reliable. However, more sources and more up-to-date information would benefit this article. Additionally, many stated facts are not linked to sources.
-=== Mercury Cycle ===
-==== Content ====
-Everything in this article is relevant to the topic of mercury cycling, and related articles are linked throughout the piece. A lot of complicated jargon is used, but these topics are generally explained or linked to an explanatory article. The primary and secondary sources of mercury are discussed in detail, and an overview of its sinks is also given. Mercury's ecological and health impacts are touched on, and well-documented within the references section, but a more detailed discussion within the article itself would be valid. The information is generally up-to-date, with most sources being less than 10 years old and all sources being less than 20 years old.
-==== Tone ====
-The tone of the article is neutral and well-balanced, including primarily perspectives in Earth systems science, and some perspectives from ecology, sustainability, and health (although more discussion of mercury's relevance to these topics would be useful).
-==== Sources ====
-This article cites sources from a wide variety of origins, including scientific publications, the World Health Organization, and ecological and sustainability organizations. Facts are linked to relevant references, with some facts even being linked to multiple references. All of the checked sources link to the correct article, and the claims that they back up are valid.
-=References=