Editing Arsenic (section)

=== Agricultural ===
[[File:Roxarsone.png|thumb|[[Roxarsone]] is a controversial arsenic compound used as a feed ingredient for chickens.]]

The toxicity of arsenic to insects, bacteria, and fungi led to its use as a [[wood preservative]].<ref>{{cite journal |doi = 10.2134/jeq2004.0173 |last1 = Rahman |first1 = F. A. |last2 = Allan |first2 = D. L. |last3 = Rosen |first3 = C. J. |last4 = Sadowsky |first4 = M. J. |title = Arsenic availability from chromated copper arsenate (CCA)-treated wood |journal = Journal of Environmental Quality |volume = 33 |issue = 1 |pages = 173–180 |date = 2004 |pmid = 14964372}}</ref> In the 1930s, a process of treating wood with [[chromated copper arsenate]] (also known as CCA or [[Tanalith]]) was invented, and for decades, this treatment was the most extensive industrial use of arsenic. An increased appreciation of the toxicity of arsenic led to a ban of CCA in consumer products in 2004, initiated by the European Union and United States.<ref>{{cite book|title = Environmental Chemistry: Green Chemistry and Pollutants in Ecosystems|editor = Lichtfouse, Eric|editor2 = Schwarzbauer, Jan|editor3 = Robert, Didier|date = 2004|isbn = 978-3-540-22860-8|chapter-url = https://books.google.com/books?id=IDGLh_cWAIwC|chapter = Electrodialytical Removal of Cu, Cr and As from Threaded Wood|first = Eric|last = Lichtfouse |publisher = Springer|location = Berlin}}</ref><ref name="round">{{cite journal|journal = Talanta|volume = 58|issue = 1|date = 2002|pages = 201–235|doi = 10.1016/S0039-9140(02)00268-0|title = Arsenic round the world: a review|first1 = Badal Kumar|last1 = Mandal|pmid = 18968746|last2 = Suzuki|first2 = K. T.}}</ref> However, CCA remains in heavy use in other countries (such as on Malaysian rubber plantations).<ref name = Ullmann />

Arsenic was also used in various agricultural insecticides and poisons. For example, [[lead hydrogen arsenate]] was a common insecticide on [[fruit tree]]s,<ref>{{cite conference|last = Peryea|first = F. J.|title = Historical use of lead arsenate insecticides, resulting in soil contamination and implications for soil remediation|conference = 16th World Congress of Soil Science|place = Montpellier, France|date = 20–26 August 1998|url = http://soils.tfrec.wsu.edu/leadhistory.htm|url-status = dead|archive-url = https://web.archive.org/web/20081207174027/http://soils.tfrec.wsu.edu/leadhistory.htm|archive-date = 7 December 2008}}</ref> but contact with the compound sometimes resulted in brain damage among those working the sprayers. In the second half of the 20th century, [[monosodium methyl arsenate]] (MSMA) and [[disodium methyl arsenate]] (DSMA) – less toxic organic forms of arsenic – replaced lead arsenate in agriculture. These organic arsenicals were in turn phased out in the United States by 2013 in all agricultural activities except cotton farming.<ref name="Federal Register">{{cite web |title=Organic Arsenicals; Notice of Receipt of Requests to Voluntarily Cancel or to Amend to Terminate Uses of Certain Pesticide Registrations |url=https://www.govinfo.gov/content/pkg/FR-2009-07-08/html/E9-16054.htm |website=Federal Register |publisher=Government Printing Office |access-date=18 July 2023}}</ref><ref>{{cite web |title=Monosodium Methanearsonate (MSMA), an Organic Arsenical |date=22 April 2015 |url=https://www.epa.gov/ingredients-used-pesticide-products/monosodium-methanearsonate-msma-organic-arsenical |publisher=Environmental Protection Agency |access-date=18 July 2023}}</ref>

The biogeochemistry of arsenic is complex and includes various adsorption and desorption processes. The toxicity of arsenic is connected to its solubility and is affected by pH. Arsenite ({{chem2|AsO3(3-)}}) is more soluble than arsenate ({{chem2|AsO4(3-)}}) and is more toxic; however, at a lower pH, arsenate becomes more mobile and toxic. It was found that addition of sulfur, phosphorus, and iron oxides to high-arsenite soils greatly reduces arsenic phytotoxicity.<ref>{{Cite web|url=https://www.crcpress.com/Trace-Elements-in-Soils-and-Plants-Third-Edition/Kabata-Pendias/p/book/9780849315756|title=Trace Elements in Soils and Plants, Third Edition|website=CRC Press|access-date=2016-08-02|archive-url=https://web.archive.org/web/20160821154852/https://www.crcpress.com/Trace-Elements-in-Soils-and-Plants-Third-Edition/Kabata-Pendias/p/book/9780849315756|archive-date=21 August 2016|url-status = dead}}</ref>

Arsenic is used as a feed additive in [[Poultry farming|poultry]] and [[Pig farming|swine production]], in particular it was used in the U.S. until 2015 to increase weight gain, improve [[feed conversion ratio|feed efficiency]], and prevent disease.<ref>{{cite journal|journal = Environmental Health Perspectives|date = 2005|volume = 113|issue = 9|pages = 1123–1124|doi = 10.1289/ehp.7834|pmid = 16140615|pmc = 1280389|title = Arsenic: A Roadblock to Potential Animal Waste Management Solutions|first1 = Keeve E.|last1 = Nachman|last2 = Graham|first2 = Jay P.|last3 = Price|first3 = Lance B.|last4 = Silbergeld|first4 = Ellen K.| bibcode=2005EnvHP.113.1123N }}</ref><ref>{{cite web |url=http://www.atsdr.cdc.gov/toxprofiles/tp2-c5.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.atsdr.cdc.gov/toxprofiles/tp2-c5.pdf |archive-date=2022-10-09 |url-status=live |title=Arsenic |at=Section 5.3, p. 310 |publisher=Agency for Toxic Substances and Disease Registry }}</ref> An example is [[roxarsone]], which had been used as a [[broiler]] starter by about 70% of U.S. broiler growers.<ref>{{cite journal|title =A Broad View of Arsenic|date = 2007|volume = 86|pages = 2–14|journal = Poultry Science|first = F. T.|last =Jones|pmid =17179408|issue =1|doi=10.1093/ps/86.1.2|doi-access =free}}</ref> In 2011, Alpharma, a subsidiary of Pfizer Inc., which produces roxarsone, voluntarily suspended sales of the drug in response to studies showing elevated levels of inorganic arsenic, a carcinogen, in treated chickens.<ref name="FDAQ&A">{{cite web |author=Staff |title=Questions and Answers Regarding 3-Nitro (Roxarsone) |url=https://www.fda.gov/AnimalVeterinary/SafetyHealth/ProductSafetyInformation/ucm258313.htm |date=8 June 2011 |publisher=[[U.S. Food and Drug Administration]] |access-date=2012-09-21 }}</ref> A successor to Alpharma, [[Zoetis]], continued to sell [[nitarsone]] until 2015, primarily for use in turkeys.<ref name="FDAQ&A" />