Atrazine

{{Short description|Herbicide}} {{Chembox | Watchedfields = changed | verifiedrevid = 443663905 | ImageFile_Ref = {{chemboximage|correct|??}} | ImageFile = AtrazineVector.svg | ImageName = Atrazine | ImageFile1 = Atrazine-3D-balls.png | ImageName1 = Atrazine | PIN = 6-Chloro-''N''2-ethyl-''N''4-(propan-2-yl)-1,3,5-triazine-2,4-diamine | OtherNames = Atrazine 1-Chloro-3-ethylamino-5-isopropylamino-2,4,6-triazine 2-Chloro-4-ethylamino-6-isopropylamino-''s''-triazine 6-Chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine |Section1={{Chembox Identifiers | ChEBI_Ref = {{ebicite|correct|EBI}} | ChEBI = 15930 | DrugBank_Ref = {{drugbankcite|correct|drugbank}} | DrugBank = DB07392 | SMILES = Clc1nc(nc(n1)NC(C)C)NCC | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 2169 | PubChem = 2256 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = QJA9M5H4IM | KEGG_Ref = {{keggcite|correct|kegg}} | KEGG = C06551 | InChI = 1/C8H14ClN5/c1-4-10-7-12-6(9)13-8(14-7)11-5(2)3/h5H,4H2,1-3H3,(H2,10,11,12,13,14) | InChIKey = MXWJVTOOROXGIU-UHFFFAOYAJ | ChEMBL_Ref = {{ebicite|correct|EBI}} | ChEMBL = 15063 | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C8H14ClN5/c1-4-10-7-12-6(9)13-8(14-7)11-5(2)3/h5H,4H2,1-3H3,(H2,10,11,12,13,14) | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = MXWJVTOOROXGIU-UHFFFAOYSA-N | CASNo_Ref = {{cascite|correct|CAS}} | CASNo = 1912-24-9 | RTECS = }} |Section2={{Chembox Properties | C=8 | H=14 | Cl=1 | N=5 | Appearance = Colorless solid | Density = 1.187 g/cm3 | Solubility = 7 mg/100 mL | MeltingPtC = 175 | BoilingPtC = 200 | BoilingPt_notes = decomposes<ref name=PGCH/> | pKa = | pKb = | Viscosity = }} |Section3={{Chembox Structure | MolShape = | Coordination = | CrystalStruct = | Dipole = }} |Section7={{Chembox Hazards | ExternalSDS = | MainHazards = | FlashPt = Noncombustible | FlashPt_ref = <ref name=PGCH/> | PEL = None<ref name=PGCH>{{PGCH|0043}}</ref> | REL = TWA 5 mg/m3<ref name=PGCH/> | IDLH = N.D.<ref name=PGCH/> }} |Section8={{Chembox Related | OtherAnions = | OtherCations = | OtherCompounds = }} }}

'''Atrazine''' ({{IPAc-en||ˈ|æ|t|r|ə|z|iː|n}} {{respell|A|trə|zeen}}) is a chlorinated herbicide of the triazine class.<ref name=EPAatrazine>{{cite news|url=https://www.epa.gov/ingredients-used-pesticide-products/atrazine|title=Ingredients Used in Pesticide Products-Atrazine|work=US Environmental Protection Agency|access-date=2021-08-08|archive-date=2022-05-06|archive-url=https://web.archive.org/web/20220506084754/https://www.epa.gov/ingredients-used-pesticide-products/atrazine|url-status=live}}</ref> It is used to prevent pre-emergence broadleaf weeds in crops such as maize (corn),<ref name="DrinkTap.org"/> soybean<ref name="DrinkTap.org">{{cite news |title=Water Info: What's In My Water?: Atrazine |url=https://drinktap.org/Water-Info/Whats-in-My-Water/Atrazine |publisher=DrinkTap.org |archive-url=https://web.archive.org/web/20180101024239/https://drinktap.org/Water-Info/Whats-in-My-Water/Atrazine |archive-date=1 January 2018}}</ref> and sugarcane, and also in turf landscaping, such as golf courses and residential lawns. Its use significantly increases crop yields.<ref name=Ackerman2007/> Atrazine is one of the most widely used herbicides in the United States,<ref name=EPAatrazine /> Canada,<ref name=:can>{{cite news |title=Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Atrazine |url=https://www.canada.ca/en/health-canada/services/publications/healthy-living/guidelines-canadian-drinking-water-quality-guideline-technical-document-atrazine.html |publisher=Health Canada |date=1 November 2011 |access-date=5 November 2022 |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105184514/https://www.canada.ca/en/health-canada/services/publications/healthy-living/guidelines-canadian-drinking-water-quality-guideline-technical-document-atrazine.html |url-status=live }}</ref> Australia,<ref name="APVMAmain">{{cite web|url=http://apvma.gov.au/node/12371|title=Chemical Review: Atrazine|publisher=Australian Pesticides and Veterinary Medicines Authority|access-date=2015-02-11|date=2014-05-28|archive-date=2015-02-11|archive-url=https://web.archive.org/web/20150211172609/http://apvma.gov.au/node/12371|url-status=live}}</ref> and Brazil,<ref>{{Cite journal |last=Brovini |first=Emília Marques |last2=de Deus |first2=Beatriz Corrêa Thomé |last3=Vilas-Boas |first3=Jéssica Andrade |last4=Quadra |first4=Gabrielle Rabelo |last5=Carvalho |first5=Luana |last6=Mendonça |first6=Raquel Fernandes |last7=Pereira |first7=Renata de Oliveira |last8=Cardoso |first8=Simone Jaqueline |date=2021-06-01 |title=Three-bestseller pesticides in Brazil: Freshwater concentrations and potential environmental risks |url=https://www.sciencedirect.com/science/article/pii/S0048969720382875 |journal=Science of the Total Environment |volume=771 |article-number=144754 |doi=10.1016/j.scitotenv.2020.144754 |issn=0048-9697|url-access=subscription }}</ref> but has been banned in other countries including in the European Union and the Gulf Cooperation Council.<ref>{{Cite web |last=والزراعة |first=وزارة البيئة والمياه |title=قائمة المبيدات المحظورة و المقيدة {{!}} وكالة الزراعة |url=https://www.mewa.gov.sa/ar/Ministry/Agencies/AgencyofAgriculture/Topics/Pages/oldblock.aspx |access-date=2026-01-21 |website=وزارة البيئة والمياه والزراعة |language=ar-SA}}</ref> Its use is controversial and highly regulated.

{{As of|2001}}, atrazine was the most common pesticide found in drinking water in the U.S.<ref name=USGS>Gilliom RJ et al. US Geological Survey [https://pubs.usgs.gov/circ/2005/1291/pdf/circ1291_chapter4.pdf The Quality of Our Nation's Waters: Pesticides in the Nation's Streams and Ground Water, 1992–2001] {{Webarchive|url=https://web.archive.org/web/20131126164946/http://pubs.usgs.gov/circ/2005/1291/pdf/circ1291_chapter4.pdf |date=2013-11-26 }} March 2006, Revised February 15, 2007</ref>{{rp|44}}

==Uses== Atrazine is an herbicide that is used to stop pre- and post-emergence broadleaf and grassy weeds in crops such as sorghum, maize, sugarcane, lupins, pine, and eucalypt plantations, and triazine-tolerant canola.<ref name="APVMAmain"/> In the United States as of 2014, atrazine was the second-most widely used herbicide after glyphosate,<ref name=yorker/> with {{convert|76|e6lb|e3MT|abbr=off}} of it applied each year,<ref>{{cite news | last = Walsh | first = Edward | title = EPA Stops Short of Banning Herbicide | url = http://www.waterconserve.org/shared/reader/welcome.aspx?linkid=19803 | pages = A14 | newspaper = Washington Post | date = 2003-02-01 | access-date = 2007-04-27 | archive-date = 2022-03-15 | archive-url = https://web.archive.org/web/20220315165734/http://www.waterconserve.org/shared/reader/welcome.aspx?linkid=19803 }}</ref><ref name=rupr>{{cite web|title=Restricted Use Products (RUP) Report: Six Month Summary List |publisher=Environmental Protection Agency |url=http://www.epa.gov/opprd001/rup/rup6mols.htm |access-date=1 December 2009 |archive-url=https://web.archive.org/web/20100111030314/http://www.epa.gov/opprd001/rup/rup6mols.htm |archive-date=11 January 2010 }}</ref> nearly identical to its usage in 1974, of 76.8 million pounds.<ref>{{cite web |title=Pesticide Usage Survey of Agricultural, Governmental, and Industrial Sectors in the United States, 1974 |url=https://nepis.epa.gov/Exe/ZyPURL.cgi?Dockey=91012P4O.txt |website=epa.gov |publisher=EPA |date=1977}}</ref>

Atrazine has a dramatic positive impact on crop yields. Corn yields has been estimated to increase from 1% to 8%.<ref name=Ackerman2007>{{Cite journal | author = Ackerman, Frank | title = The economics of atrazine | journal = International Journal of Occupational and Environmental Health | volume = 13 | issue = 4 | pages = 437–445 | year = 2007 | pmid = 18085057 | url = http://ase.tufts.edu/gdae/Pubs/rp/EconAtrazine.pdf | doi = 10.1179/oeh.2007.13.4.437 | s2cid = 2655422 | author-link = Frank Ackerman | access-date = 2010-11-28 | archive-date = 2011-06-22 | archive-url = https://web.archive.org/web/20110622114756/http://ase.tufts.edu/gdae/Pubs/rp/EconAtrazine.pdf | url-status = live }}</ref><ref>{{cite journal |title=BioOne Online Journals - A Rationale for Atrazine Stewardship in Corn |doi=10.1614/WS-06-104.1 |volume=55 |journal=Weed Science|pages=75–81|year = 2017|last1 = Swanton|first1 = Clarence J|last2= Gulden|first2= Robert H|last3= Chandler|first3= Kevin|s2cid=86209323 }}</ref> In another study looking at combined data from 236 university corn field trials from 1986 to 2005, atrazine treatments showed an average increase of {{Convert|5.7|USbu/acre}} (~{{Convert|400|kg/ha}}) than alternative herbicide treatments.<ref name=NCWSS>Fawcett, Richard S. "[http://www.ncwss.org/proceed/2008/abstracts/137.pdf Twenty Years of University Corn Yield Data: With and Without Atrazine] {{Webarchive|url=https://web.archive.org/web/20090514160003/http://www.ncwss.org/proceed/2008/abstracts/137.pdf |date=2009-05-14 }}", [http://www.ncwss.org/about.php North Central Weed Science Society] {{webarchive|url=https://web.archive.org/web/20140305163756/http://www.ncwss.org/about.php |date=March 5, 2014 }}, 2008</ref> Effects on sorghum yields have been estimated to be as high as 20%, owing in part to the absence of alternative weed control products that can be used on sorghum.<ref>{{cite journal |title=Market-level assessment of the economic benefits of atrazine in the United States | doi=10.1002/ps.3703 | pmid=24318916 |volume=70 | issue=11 |journal=Pest Management Science|pages=1684–1696|pmc=4282455|year = 2014|last1 = Mitchell|first1 = P. D}}</ref>

==Chemistry and biochemistry== Atrazine was invented in 1958 in the Geigy laboratories as the second of a series of 1,3,5-triazines.<ref>{{cite book|url=https://books.google.com/books?id=CdBpwokWL08C&pg=PA360|title=Modern Crop Protection Compounds, Volume 1|author=Wolfgang Krämer|year=2007|publisher=Wiley-VCH|isbn=978-3-527-31496-6}}{{Dead link|date=April 2023 |bot=InternetArchiveBot |fix-attempted=yes }} (dead link 22 June 2022)</ref>

Atrazine is prepared from cyanuric chloride, which is treated sequentially with ethylamine and isopropylamine. Like other triazine herbicides, atrazine functions by binding to the plastoquinone-binding protein in photosystem II, which animals lack. Plant death results from starvation and oxidative damage caused by breakdown in the electron transport process. Oxidative damage is accelerated at high light intensity.<ref>{{Cite encyclopedia | last1 = Appleby | first1 = Arnold P. | last2 = Müller | first2 = Franz | last3 = Carpy | first3 = Serge | doi = 10.1002/14356007.a28_165 | encyclopedia = Ullmann's Encyclopedia of Industrial Chemistry | year = 2001 | isbn = 978-3-527-30673-2 | chapter = Weed Control }}</ref>

Atrazine has been found to act as an agonist of the G protein-coupled estrogen receptor 1.<ref name="ProssnitzBarton2014">{{cite journal |last1=Prossnitz |first1=Eric R. |last2=Barton |first2=Matthias |title=Estrogen biology: New insights into GPER function and clinical opportunities |journal=Molecular and Cellular Endocrinology|date=May 2014 |volume=389 |issue=1–2 |pages=71–83 |doi=10.1016/j.mce.2014.02.002 |pmid=24530924 |pmc=4040308 }}</ref> Atrazine has been shown to bind covalently to (chemically react with) a large number of mammalian proteins.<ref>{{cite journal |last1=Dooley |first1=G. P. |last2=Reardon |first2=K. F. |last3=Prenni |first3=J. E. |last4=Tjalkens |first4=R. B. |last5=Legare |first5=M. E. |last6=Foradori |first6=C. D. |last7=Tessari |first7=J. E. |last8=Hanneman |first8=W. H. |title=Proteomic Analysis of Diaminochlorotriazine Adducts in Wister Rat Pituitary Glands and LβT2 Rat Pituitary Cells |journal=Chemical Research in Toxicology|date=April 2008 |volume=21 |issue=4 |pages=844–851 |doi=10.1021/tx700386f |pmid=18370413 }}</ref>

==Degradation== [[File:Pathway Atrazine degradation.svg|thumb|300px|right|Atrazine chlorohydrolase pathway|alt=Biodegradation - atrazine chlorohydrolase pathway]] Atrazine remains in soil for a matter of months (although in some soils can persist to at least four years)<ref name=AtrazineChemSummEPA/> and can migrate from soil to groundwater; once in groundwater, it degrades slowly. The low rates of biodegradation are attributed to atrazine's low solubility. It has been detected in groundwater at high levels in some regions of the U.S. where it is used on some crops and turf. The U.S. Environmental Protection Agency expresses concern regarding contamination of surface waters (lakes, rivers, and streams).<ref name=AtrazineChemSummEPA /> Atrazine rapidly degrades in the presence of reduced iron-bearing soil clays, such as ferruginous smectites.<ref>{{cite journal |vauthors=Xu J, Stucki JW, Wu J, Kostka J, Sims GK | year = 2001 | title = Fate of atrazine and alachlor in redox-treated ferruginous smectite | journal = Environmental Toxicology and Chemistry | volume = 20 | pages = 2717–2724 | doi = 10.1002/etc.5620201210 | issue = 12| pmid = 11764154 | s2cid = 24221011 }}</ref>

Irradiation with 254 nm (ultraviolet light) degrades atrazine.<ref name=fdel>[https://www.researchgate.net/profile/Francisco_Pereira20/publication/310843049_Photolytic_Degradation_of_Herbicide_Atrazine_by_Radiation_Ultraviolet_UVC_An_Application_of_Green_Chemistry/links/5839959a08aef00f3bfbba30/Photolytic-Degradation-of-Herbicide-Atrazine-by-Radiation-Ultraviolet-UVC-An-Application-of-Green-Chemistry.pdf Felix de Lima et al, "Photolytic Degradation of Herbicide Atrazine by Radiation Ultraviolet (UVC): An Application of Green Chemistry"] {{Webarchive|url=https://web.archive.org/web/20180502140748/https://www.researchgate.net/profile/Francisco_Pereira20/publication/310843049_Photolytic_Degradation_of_Herbicide_Atrazine_by_Radiation_Ultraviolet_UVC_An_Application_of_Green_Chemistry/links/5839959a08aef00f3bfbba30/Photolytic-Degradation-of-Herbicide-Atrazine-by-Radiation-Ultraviolet-UVC-An-Application-of-Green-Chemistry.pdf |date=2018-05-02 }}, Chemical Science International Journal 17(3): 1-10, 2016</ref>

===Biodegradation=== Atrazine biodegradation occur by two pathways:

# Hydrolysis of the C-Cl bond is followed by the ethyl and isopropyl groups, catalyzed by the hydrolase enzymes called AtzA, AtzB, and AtzC. The end product of this process is cyanuric acid, itself unstable with respect to ammonia and carbon dioxide. The best characterized organisms that use this pathway are of ''Pseudomonas'' sp. strain ADP. # Dealkylation of the amino groups gives 2-chloro-4-hydroxy-6-amino-1,3,5-triazine, the degradation of which is unknown. This path also occurs in ''Pseudomonas'' species, as well as a number of bacteria.<ref name="wackett">{{cite journal |last1=Wackett |first1=L. P. |last2=Sadowsky |first2=M. J. |last3=Martinez |first3=B. |last4=Shapir |title=Biodegradation of atrazine and related s-triazine compounds: from enzymes to field studies |journal=Applied Microbiology and Biotechnology |volume=58 |issue=1 |pages=39–45 |date=January 2002 |pmid=11831474 |doi= 10.1007/s00253-001-0862-y |first4=N.|s2cid=2998290 }}</ref>

A common pathway for atrazine degradation involves the intermediate cyanuric acid, which can serve as a nitrogen source for aerobic microorganisms. Some aerobic atrazine degraders have been shown to use the compound for growth under anoxia in the presence of nitrate as an electron acceptor,<ref>{{cite journal |vauthors=Crawford JJ, Sims GK, Mulvaney RL, Radosevich M | year = 1998 | title = Biodegradation of atrazine under denitrifying conditions | journal = Appl. Microbiol. Biotechnol. | volume = 49 | pages = 618–623 | doi = 10.1007/s002530051223 | pmid = 9650260 | issue = 5| s2cid = 5126687 }}</ref><ref>{{cite journal |author1=Bichat, F. |author2=G.K. Sims |author3=R.L. Mulvaney | year = 1999 | title = Microbial utilization of heterocyclic nitrogen from atrazine | journal = Soil Science Society of America Journal | volume = 63 | issue = 1 | pages = 100–110 | doi = 10.2136/sssaj1999.03615995006300010016x| bibcode = 1999SSASJ..63..100B }}</ref><ref>{{cite journal | vauthors = Ralebitso TK, Senior E, van Verseveld HW | year = 2002 | title = Microbial aspects of atrazine degradation in natural environments | journal = Biodegradation | volume = 13 | issue = 1 | pages = 11–19 | doi = 10.1023/A:1016329628618 | pmid = 12222950 | s2cid = 21098999 | url = https://research.tees.ac.uk/en/publications/c8197257-2338-4626-8ca5-73f70b276b73 | access-date = 2019-10-29 | archive-date = 2022-03-15 | archive-url = https://web.archive.org/web/20220315165609/https://research.tees.ac.uk/en/publications/microbial-aspects-of-atrazine-degradation-in-natural-environments | url-status = live }}</ref>

The genes for enzymes AtzA-C are highly conserved in atrazine-degrading organisms.<ref>{{cite journal |vauthors=Cai B, Han Y, Liu B, Ren Y, Jiang S | year = 2003 | title = Isolation and characterization of an atrazine-degrading bacterium from industrial wastewater in China | journal = Letters in Applied Microbiology | volume = 36 | pages = 272–276 | doi = 10.1046/j.1472-765X.2003.01307.x | pmid=12680937 | issue = 5| s2cid = 8003165 }}</ref> The insertion elements flanking each gene suggest that they are involved in the assembly of this specialized catabolic pathway.<ref name="wackett"/>

==Toxicology== According to Extension Toxicology Network in the U.S., "The oral median Lethal Dose or {{LD50}} for atrazine is 3090 mg/kg in rats, 1750 mg/kg in mice, 750 mg/kg in rabbits, and 1000 mg/kg in hamsters. The dermal LD50 in rabbits is 7500 mg/kg. The 1-hour inhalation LC50 is greater than 0.7 mg/L in rats. The 4-hour inhalation LC50 is 5.2 mg/L in rats." The maximum contaminant level is 0.003 mg/L and the reference dose is 0.035 mg/kg/day.<ref>[http://extoxnet.orst.edu/pips/atrazine.htm Pesticide Information Profile: Atrazine] {{Webarchive|url=https://web.archive.org/web/20220401033349/http://extoxnet.orst.edu/pips/atrazine.htm |date=2022-04-01 }}, Extension Toxicology Network (Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho, and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University), June 1996.</ref> thumb|Atrazine use in the U.S. in 2019

===Cancer=== In 2025, IARC updated the classification of atrazine to be "probably carcinogenic to humans" (Group 2A).<ref name="iarc25">{{cite web |title=IARC Monographs evaluation of the carcinogenicity of atrazine, alachlor, and vinclozolin |url=https://www.iarc.who.int/news-events/iarc-monographs-evaluation-of-the-carcinogenicity-of-atrazine-alachlor-and-vinclozolin/ |publisher=IARC |access-date=14 December 2025 |date=November 21, 2025}}</ref> A 2011 study that tracked 57,310 licensed American pesticide applicators over 13 years concluded that "there was no consistent evidence of an association between atrazine use and any cancer site".<ref name=EHP2011>Beane Freeman, Laura E. (2011) ''[http://ehp03.niehs.nih.gov/article/fetchArticle.action;jsessionid=16CAEF820312206AF426693F83851464?articleURI=info:doi/10.1289/ehp.1103561 Atrazine and Cancer Incidence Among Pesticide Applicators in the Agricultural Health Study (1994–2007)] {{Webarchive|url=https://web.archive.org/web/20120328114218/http://ehp03.niehs.nih.gov/article/fetchArticle.action;jsessionid=16CAEF820312206AF426693F83851464?articleURI=info%3Adoi%2F10.1289%2Fehp.1103561 |date=2012-03-28 }}.'' Environmental Health Perspectives.</ref>

===General reproductive health=== Studies suggest it is an endocrine disruptor, an agent that can alter the natural hormonal system.<ref name=AtrazineChemSummEPA>{{Cite report|date=2007-04-24 |title=Atrazine: Chemical Summary. Toxicity and Exposure Assessment for Children's Health |url=http://www.epa.gov/teach/chem_summ/Atrazine_summary.pdf |publisher=U.S. Environmental Protection Agency |archive-url=https://web.archive.org/web/20120316130312/http://www.epa.gov/teach/chem_summ/Atrazine_summary.pdf |archive-date=2012-03-16 }}</ref>

Some studies have been complicated by poor reproducibility<ref>{{cite journal |last1=Renner |first1=Rebecca |title=Atrazine Effects in Xenopus Aren't Reproducible |journal=Environmental Science & Technology |date=May 2008 |volume=42 |issue=10 |pages=3491–3493 |doi=10.1021/es087113j |pmid=18546678 |bibcode=2008EnST...42.3491R |doi-access=free }}</ref> conflicts of interest,<ref>{{cite journal |last1=Rohr |first1=Jason R. |title=The Atrazine Saga and its Importance to the Future of Toxicology, Science, and Environmental and Human Health |journal=Environmental Toxicology and Chemistry |year=2021 |volume=40 |issue=6 |pages=1544–1558 |doi=10.1002/etc.5037 |pmid=33999476 |bibcode=2021EnvTC..40.1544R |url=https://setac.onlinelibrary.wiley.com/doi/full/10.1002/etc.5037 |url-access=subscription }}</ref> and accusations of retribution.<ref name=yorker>{{cite magazine|url=http://www.newyorker.com/reporting/2014/02/10/140210fa_fact_aviv?currentPage=all|title=A Valuable Reputation: Tyrone Hayes said that a chemical was harmful, its maker pursued him|archive-url=https://web.archive.org/web/20140702091502/http://www.newyorker.com/reporting/2014/02/10/140210fa_fact_aviv?currentPage=all|archive-date=2014-07-02|first=Rachel|last= Aviv|work=The New Yorker|date=10 February 2014}}</ref><ref name="NYT">{{cite news|url=https://www.nytimes.com/2009/08/23/us/23water.html?_r=1&hp=&pagewanted=all|title=Debating How Much Weed Killer Is Safe in Your Water Glass|last=Duhigg|first=Charles|date=August 22, 2009|work=The New York Times|access-date=2015-05-02|archive-date=2018-11-07|archive-url=https://web.archive.org/web/20181107104048/https://www.nytimes.com/2009/08/23/us/23water.html?_r=1&hp=&pagewanted=all|url-status=live}}</ref>

The U.S. EPA's Scientific Advisory Panel examined relevant studies and concluded in 2010, "atrazine does not adversely affect amphibian gonadal development based on a review of laboratory and field studies".<ref name=EPAUpdateAmphib>[http://www.epa.gov/pesticides/reregistration/atrazine/atrazine_update.htm#amphibian Atrazine Updates: Amphibians] {{Webarchive|url=https://web.archive.org/web/20150930062846/http://www.epa.gov/pesticides/reregistration/atrazine/atrazine_update.htm#amphibian |date=2015-09-30 }}, April 2010, EPA.</ref> It recommended proper study design for further investigation. As required by the EPA, two experiments were conducted under Good Laboratory Practices (GLP) and were inspected by EPA and German regulatory authorities, concluding 2009 that "long-term exposure of larval ''X. laevis'' to atrazine at concentrations ranging from 0.01 to 100 μg/L does not affect growth, larval development, or sexual differentiation".<ref>{{cite journal |last1=Kloas |first1=Werner |last2=Lutz |first2=Ilka |last3=Springer |first3=Timothy |last4=Krueger |first4=Henry |last5=Wolf |first5=Jeff |last6=Holden |first6=Larry |last7=Hosmer |first7=Alan |title=Does Atrazine Influence Larval Development and Sexual Differentiation in Xenopus laevis? |journal=Toxicological Sciences |date=February 2009 |volume=107 |issue=2 |pages=376–384 |doi=10.1093/toxsci/kfn232 |pmid=19008211 |pmc=2639758 }}</ref>

Atrazine may affect reproduction of minnows.<ref name=TillittFish>{{cite journal |vauthors=Tillitt DE, Papoulias DM, Whyte JJ, Richter CA |title=Atrazine reduces reproduction in fathead minnow (Pimephales promelas) |journal=Aquat. Toxicol. |volume=99 |issue=2 |pages=149–59 |year=2010 |pmid=20471700 |doi=10.1016/j.aquatox.2010.04.011 |bibcode=2010AqTox..99..149T |url=https://zenodo.org/record/1258744 |access-date=2020-09-01 |archive-date=2022-03-15 |archive-url=https://web.archive.org/web/20220315165735/https://zenodo.org/record/1258744 |url-status=live }}</ref>

A 2011 review of the mammalian reproductive toxicology of atrazine jointly conducted by the World Health Organization and the Food and Agriculture Organization of the United Nations concluded that atrazine was not teratogenic. Reproductive effects in rats and rabbits were only seen at doses that were toxic to the mother. Observed adverse effects in rats included fetal resorption in rates (at doses ≥50 mg/kg per day), delays in sexual development in female rats (at doses ≥30 mg/kg per day), and decreased birth weight (at doses ≥3.6 mg/kg per day).<ref>{{cite web |url=https://www.who.int/water_sanitation_health/dwq/chemicals/antrazine.pdf?ua=1 |title=Chemical Hazards in Drinking Water - Atrazine |access-date=2015-02-08 |archive-date=2022-03-15 |archive-url=https://web.archive.org/web/20220315165558/https://www.who.int/water_sanitation_health/dwq/chemicals/antrazine.pdf?ua=1 |url-status=live }}</ref>

A 2014 systematic review, funded by atrazine manufacturer Syngenta, assessed its relation to reproductive health problems. The authors concluded that the quality of most studies was poor and without good quality data, the results were difficult to assess, though it was noted that no single category of negative pregnancy outcome was found consistently across studies. The authors concluded that a causal link between atrazine and adverse pregnancy outcomes was not warranted due to the poor quality of the data and the lack of robust findings across studies. Syngenta was not involved in the design, collection, management, analysis, or interpretation of the data and did not participate in the preparation of the manuscript.<ref>{{Cite journal | pmid = 24797711 | pmc = 4265844 | year = 2014 | last1 = Goodman | first1 = M | title = Atrazine and pregnancy outcomes: A systematic review of epidemiologic evidence | journal = Birth Defects Research Part B: Developmental and Reproductive Toxicology | volume = 101 | issue = 3 | pages = 215–36 | last2 = Mandel | first2 = J. S. | last3 = Desesso | first3 = J. M. | last4 = Scialli | first4 = A. R. | doi = 10.1002/bdrb.21101 }}</ref>

===Aquatic impacts and regulation=== According to the U.S. EPA, the maximum allowable atrazine concentration in drinking water is 3 μg/L. This level was established in 2011 and remains in place in 2025.<ref>{{cite web |title=Public Health Statement for Atrazine |url=https://wwwn.cdc.gov/TSP/PHS/PHS.aspx?phsid=336&toxid=59 |website=Agency for Toxic Substances and Disease Registry}}</ref>

Because it is pervasive in run-off, its impact on aquatic life has been scrutinized.<ref>{{cite journal |last1=Graymore |first1=M. |last2=Stagnitti |first2=F. |last3=Allinson |first3=G. |title=Impacts of atrazine in aquatic ecosystems |journal=Environment International |date=2001 |volume=26 |issue=7–8 |pages=483–495 |doi=10.1016/s0160-4120(01)00031-9 |pmid=11485216 |bibcode=2001EnInt..26..483G }}</ref> A Natural Resources Defense Council report from 2009 said that the EPA is ignoring atrazine contamination in surface and drinking water in the central United States.<ref name="NRDC, Poisoning the Well">{{cite news | url=http://graphics8.nytimes.com/packages/pdf/us/NRDC-Atrazine-report.pdf?scp=2&sq=atrazine&st=cse | work=Natural Resources Defense Council | publisher=The New York Times | title=How the EPA is Ignoring Atrazine Contamination in Surface and Drinking Water in the Central United States | date=August 2009 | access-date=2010-12-19 | archive-date=2022-04-17 | archive-url=https://web.archive.org/web/20220417140446/https://graphics8.nytimes.com/packages/pdf/us/NRDC-Atrazine-report.pdf?scp=2&sq=atrazine&st=cse | url-status=live }}</ref> Atrazine has a negative impact on aquatic life.<ref name=Wang>{{cite journal |last1=Wang |first1=Shoumeng |last2=Yang |first2=Yang |last3=Li |first3=Dongzhi |last4=Xie |first4=Lanfen |last5=Wu |first5=Yanbing |last6=Li |first6=Guangling |title=Current Research Status, Opportunities, and Future Challenges of Nine Representative Persistent Herbicides |journal=Journal of Agricultural and Food Chemistry |date=2024 |volume=72 |issue=40 |pages=21959–21972 |doi=10.1021/acs.jafc.4c04537 |pmid=39331366 |bibcode=2024JAFC...7221959W }}</ref>

In 2010, the Australian Pesticides and Veterinary Medicines Authority (APVMA) tentatively concluded that environmental atrazine "at existing levels of exposure" was not affecting amphibian populations in Australia consistent with the 2007 U.S. EPA findings.<ref name="apvma2010">[https://web.archive.org/web/20100704154517/http://www.apvma.gov.au/news_media/chemicals/atrazine.php Chemicals in the News: Atrazine], Australian Pesticides and Veterinary Medicines Authority, Original June 30, 2010, Archived by Internet Archive July 4, 2010</ref> APVMA responded to Hayes' 2010 published paper,<ref>{{cite journal | pmid = 20194757 | year = 2010 | last1 = Hayes | first1 = TB | last2 = Khoury | first2 = V | last3 = Narayan | first3 = A | last4 = Nazir | first4 = M | last5 = Park | first5 = A | last6 = Brown | first6 = T | last7 = Adame | first7 = L | last8 = Chan | first8 = E | last9 = Buchholz | first9 = D | last10 = Stueve | first10 = T. | last11 = Gallipeau | first11 = S. | title = Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis) | volume = 107 | issue = 10 | pages = 4612–7 | doi = 10.1073/pnas.0909519107 | pmc = 2842049 | journal = Proceedings of the National Academy of Sciences of the United States of America| display-authors = 8 | bibcode = 2010PNAS..107.4612H | doi-access = free }}</ref> that his findings "do not provide sufficient evidence to justify a reconsideration of current regulations which are based on a very extensive dataset".<ref name="apvma2010" />

==Regulatory action==

Its use was banned in the European Union in 2004.<ref name=EUban>European Commission. [http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=uriserv:OJ.L_.2004.078.01.0053.01.ENG 2004/248/EC: Commission Decision of 10 March 2004 concerning the non-inclusion of atrazine in Annex I to Council Directive 91/414/EEC and the withdrawal of authorisations for plant protection products containing this active substance (Text with EEA relevance) (notified under document number C(2004) 731)] {{Webarchive|url=https://web.archive.org/web/20220315165754/https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=uriserv:OJ.L_.2004.078.01.0053.01.ENG |date=15 March 2022 }}</ref><ref>Danny Hakimfeb for the New York Times. February 23, 2015. [https://www.nytimes.com/2015/02/24/business/international/a-pesticide-banned-or-not-underscores-trans-atlantic-trade-sensitivities.html?_r=0 A Pesticide Banned, or Not, Underscores Trans-Atlantic Trade Sensitivities] {{Webarchive|url=https://web.archive.org/web/20161223091121/http://www.nytimes.com/2015/02/24/business/international/a-pesticide-banned-or-not-underscores-trans-atlantic-trade-sensitivities.html?_r=0 |date=2016-12-23 }}</ref>

In Canada, the PMRA allowed the product's registration to remain unchanged in 2015. For context, the EU's ban was based on a maximum acceptable pollutant level of 0.1 μg/L. The U.S. drinking water standard is 3 μg/L; the Canadian standard is 5 μg/L.<ref name="PMRA17">{{cite news |title=Re-evaluation Note REV2017-09, Special Review Decision: Atrazine |url=https://www.canada.ca/en/health-canada/services/consumer-product-safety/reports-publications/pesticides-pest-management/decisions-updates/reevaluation-note/2017/atrazine-rev-2017-09.html |publisher=Pest Management Regulatory Agency |date=31 March 2017 |access-date=5 November 2022 |archive-date=5 November 2022 |archive-url=https://web.archive.org/web/20221105192643/https://www.canada.ca/en/health-canada/services/consumer-product-safety/reports-publications/pesticides-pest-management/decisions-updates/reevaluation-note/2017/atrazine-rev-2017-09.html |url-status=live }}</ref>

==Legal actions== In 2012, Syngenta, an atrazine manufacturer, was the defendant in a class-action lawsuit concerning the levels of atrazine in human water supplies. Syngenta agreed to pay $105 million to reimburse more than one thousand water systems for "the cost of filtering atrazine from drinking water". The company denied all wrongdoing.<ref name=yorker/><ref>[http://www.atrazinesettlement.com/ City of Greenville v. Syngenta Crop Protection, Inc., and Syngenta AG Case No. 3:10-cv-00188-JPG-PMF] {{Webarchive|url=https://web.archive.org/web/20210506104414/http://atrazinesettlement.com/ |date=2021-05-06 }}, accessed August 23, 2013</ref><ref>Clare Howard for Environmental Health News. June 17, 2013 [http://www.environmentalhealthnews.org/ehs/news/2013/atrazine Special Report: Syngenta's campaign to protect atrazine, discredit critics.] {{Webarchive|url=https://web.archive.org/web/20140330221647/http://www.environmentalhealthnews.org/ehs/news/2013/atrazine |date=2014-03-30 }}</ref>

==References== {{Reflist|colwidth=35em}}

==External links== * [https://pubchem.ncbi.nlm.nih.gov/compound/Atrazine Atrazine]- PubChem(National library of medicine) - atrazine * [http://npic.orst.edu/factsheets/atrazine.html Atrazine Fact Sheet] - National Pesticide Information Center - Atrazine Fact Sheet * [https://www.cdc.gov/niosh/npg/npgd0043.html Atrazine] - CDC - NIOSH Pocket Guide to Chemical Hazards * {{PPDB|43}}

Category:Endocrine disruptors Category:GPER agonists Category:Herbicides Category:Triazines Category:Chloroarenes Category:Suspected teratogens Category:Xenoestrogens Category:Isopropylamino compounds Category:Group 5 herbicides Category:IARC Group 2A carcinogens