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Atrazine
Atrazine
Atrazine
Atrazine
Atrazine
Names
Preferred IUPAC name
6-Chloro-N2-ethyl-N4-(propan-2-yl)-1,3,5-triazine-2,4-diamine
Other names
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
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.016.017 Edit this at Wikidata
KEGG
UNII
  • InChI=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) checkY
    Key: MXWJVTOOROXGIU-UHFFFAOYSA-N checkY
  • 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)
    Key: MXWJVTOOROXGIU-UHFFFAOYAJ
  • Clc1nc(nc(n1)NC(C)C)NCC
Properties
C8H14ClN5
Molar mass 215.69 g·mol−1
Appearance Colorless solid
Density 1.187 g/cm3
Melting point 175 °C (347 °F; 448 K)
Boiling point 200 °C (392 °F; 473 K) decomposes[1]
7 mg/100 mL
Hazards
Flash point Noncombustible[1]
NIOSH (US health exposure limits):
PEL (Permissible)
 None[1]
REL (Recommended)
 TWA 5 mg/m3[1]
IDLH (Immediate danger)
 N.D.[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Atrazine (/ˈætrəziːn/ A-trə-zeen) is a chlorinated herbicide of the triazine class.[2] It is used to prevent pre-emergence broadleaf weeds in crops such as maize (corn),[3] soybean[3] and sugarcane and on turf, such as golf courses and residential lawns. Its use significantly increases crop yields.[4] It is one of the most widely used herbicides in the United States,[2] Canada,[5] and Australia.[6] Its use is controversial and highly regulated.

As of 2001, atrazine was the most common pesticide found in drinking water in the U.S.[7]: 44 

Uses

[edit]

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.[6] In the United States as of 2014, atrazine was the second-most widely used herbicide after glyphosate,[8] with 76 million pounds (34 thousand metric tons) of it applied each year,[9][10] nearly identical to its usage in 1974, of 76.8 million pounds.[11]

Atrazine has a dramatic positive impact on crop yields. Corn yields has been estimated to increase from 1% to 8%.[4][12] In another study looking at combined data from 236 university corn field trials from 1986 to 2005, atrazine treatments showed an average increase of 5.7 US bushels per acre (0.50 m3/ha) (~400 kilograms per hectare (360 lb/acre)) than alternative herbicide treatments.[13] 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.[14]

Chemistry and biochemistry

[edit]

Atrazine was invented in 1958 in the Geigy laboratories as the second of a series of 1,3,5-triazines.[15]

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.[16]

Atrazine has been found to act as an agonist of the G protein-coupled estrogen receptor 1.[17] Atrazine has been shown to bind covalently to (chemically react with) a large number of mammalian proteins.[18]


Degradation

[edit]
Biodegradation - atrazine chlorohydrolase pathway
Atrazine chlorohydrolase pathway

Atrazine remains in soil for a matter of months (although in some soils can persist to at least four years)[19] 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).[19] Atrazine rapidly degrades in the presence of reduced iron-bearing soil clays, such as ferruginous smectites.[20]

Irradiation with 254 nm (ultraviolet light) degrades atrazine.[21]

Biodegradation

[edit]

Atrazine biodegradation occur by two pathways:

  1. 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.
  2. 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.[22]

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,[23] [24][25]

The genes for enzymes AtzA-C are highly conserved in atrazine-degrading organisms.[26] The insertion elements flanking each gene suggest that they are involved in the assembly of this specialized catabolic pathway.[22]

Toxicology

[edit]

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.[27]

Atrazine use in the U.S. in 2019

Cancer

[edit]

In 2025, IARC updated the classification of atrazine to be "probably carcinogenic to humans" (Group 2A).[28] 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".[29]

General reproductive health

[edit]

Studies suggest it is an endocrine disruptor, an agent that can alter the natural hormonal system.[19]

Some studies have been complicated by poor reproducibility[30] conflicts of interest,[31] and accusations of retribution.[8][32]

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".[33] 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".[34]

Atrazine may affect reproduction of minnows.[35]

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).[36]

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.[37]

Aquatic impacts and regulation

[edit]

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.[38]

Because it is pervasive in run-off, its impact on aquatic life has been scrutinized.[39] 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.[40] Atrazine has a negative impact on aquatic life.[41]

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.[42] APVMA responded to Hayes' 2010 published paper,[43] that his findings "do not provide sufficient evidence to justify a reconsideration of current regulations which are based on a very extensive dataset."[42]

Regulatory action

[edit]

Its use was banned in the European Union in 2004.[44][45]

In Canada, the PMRA allowed the product's registration unchanged in 2015. For context, the EU's ban was based on a pollutant level of 0.1 μg/L and the U.S. drinking water standard is 3 μg/L, the Canadian standard is 2.32 μg/L.[46]

[edit]

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.[8][47][48]

See also

[edit]

References

[edit]
  1. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0043". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ a b "Ingredients Used in Pesticide Products-Atrazine". US Environmental Protection Agency. Archived from the original on 2022-05-06. Retrieved 2021-08-08.
  3. ^ a b "Water Info : What's In My Water?: Atrazine". DrinkTap.org. Archived from the original on 1 January 2018.
  4. ^ a b Ackerman, Frank (2007). "The economics of atrazine" (PDF). International Journal of Occupational and Environmental Health. 13 (4): 437–445. doi:10.1179/oeh.2007.13.4.437. PMID 18085057. S2CID 2655422. Archived (PDF) from the original on 2011-06-22. Retrieved 2010-11-28.
  5. ^ "Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Atrazine". Health Canada. 1 November 2011. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  6. ^ a b "Chemical Review: Atrazine". Australian Pesticides and Veterinary Medicines Authority. 2014-05-28. Archived from the original on 2015-02-11. Retrieved 2015-02-11.
  7. ^ Gilliom RJ et al. US Geological Survey The Quality of Our Nation's Waters: Pesticides in the Nation's Streams and Ground Water, 1992–2001 Archived 2013-11-26 at the Wayback Machine March 2006, Revised February 15, 2007
  8. ^ a b c "A Valuable Reputation: Tyrone Hayes said that a chemical was harmful, its maker pursued him" Archived 2014-07-02 at the Wayback Machine by Rachel Aviv, The New Yorker, 10 February 2014
  9. ^ Walsh, Edward (2003-02-01). "EPA Stops Short of Banning Herbicide". Washington Post. pp. A14. Archived from the original on 2022-03-15. Retrieved 2007-04-27.
  10. ^ "Restricted Use Products (RUP) Report: Six Month Summary List". Environmental Protection Agency. Archived from the original on 11 January 2010. Retrieved 1 December 2009.
  11. ^ "Pesticide Usage Survey of Agricultural, Governmental, and Industrial Sectors in the United States, 1974". epa.gov. EPA. 1977.
  12. ^ Swanton, Clarence J; Gulden, Robert H; Chandler, Kevin (2017). "BioOne Online Journals - A Rationale for Atrazine Stewardship in Corn". Weed Science. 55: 75–81. doi:10.1614/WS-06-104.1. S2CID 86209323.
  13. ^ Fawcett, Richard S. "Twenty Years of University Corn Yield Data: With and Without Atrazine Archived 2009-05-14 at the Wayback Machine", North Central Weed Science Society Archived March 5, 2014, at the Wayback Machine, 2008
  14. ^ Mitchell, P. D (2014). "Market-level assessment of the economic benefits of atrazine in the United States". Pest Management Science. 70 (11): 1684–1696. doi:10.1002/ps.3703. PMC 4282455. PMID 24318916.
  15. ^ Wolfgang Krämer (2007). Modern Crop Protection Compounds, Volume 1. Wiley-VCH. ISBN 978-3-527-31496-6.[permanent dead link] (dead link 22 June 2022)
  16. ^ Appleby, Arnold P.; Müller, Franz; Carpy, Serge (2001). "Weed Control". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a28_165. ISBN 978-3-527-30673-2.
  17. ^ Prossnitz, Eric R.; Barton, Matthias (May 2014). "Estrogen biology: New insights into GPER function and clinical opportunities". Molecular and Cellular Endocrinology. 389 (1–2): 71–83. doi:10.1016/j.mce.2014.02.002. PMC 4040308. PMID 24530924.
  18. ^ Dooley, G. P.; Reardon, K. F.; Prenni, J. E.; Tjalkens, R. B.; Legare, M. E.; Foradori, C. D.; Tessari, J. E.; Hanneman, W. H. (April 2008). "Proteomic Analysis of Diaminochlorotriazine Adducts in Wister Rat Pituitary Glands and LβT2 Rat Pituitary Cells". Chemical Research in Toxicology. 21 (4): 844–851. doi:10.1021/tx700386f. PMID 18370413.
  19. ^ a b c Atrazine: Chemical Summary. Toxicity and Exposure Assessment for Children's Health (PDF) (Report). U.S. Environmental Protection Agency. 2007-04-24. Archived from the original (PDF) on 2012-03-16.
  20. ^ Xu J, Stucki JW, Wu J, Kostka J, Sims GK (2001). "Fate of atrazine and alachlor in redox-treated ferruginous smectite". Environmental Toxicology and Chemistry. 20 (12): 2717–2724. doi:10.1002/etc.5620201210. PMID 11764154. S2CID 24221011.
  21. ^ Felix de Lima et al, "Photolytic Degradation of Herbicide Atrazine by Radiation Ultraviolet (UVC): An Application of Green Chemistry" Archived 2018-05-02 at the Wayback Machine, Chemical Science International Journal 17(3): 1-10, 2016
  22. ^ a b Wackett, L. P.; Sadowsky, M. J.; Martinez, B.; Shapir, N. (January 2002). "Biodegradation of atrazine and related s-triazine compounds: from enzymes to field studies". Applied Microbiology and Biotechnology. 58 (1): 39–45. doi:10.1007/s00253-001-0862-y. PMID 11831474. S2CID 2998290.
  23. ^ Crawford JJ, Sims GK, Mulvaney RL, Radosevich M (1998). "Biodegradation of atrazine under denitrifying conditions". Appl. Microbiol. Biotechnol. 49 (5): 618–623. doi:10.1007/s002530051223. PMID 9650260. S2CID 5126687.
  24. ^ Bichat, F.; G.K. Sims; R.L. Mulvaney (1999). "Microbial utilization of heterocyclic nitrogen from atrazine". Soil Science Society of America Journal. 63 (1): 100–110. Bibcode:1999SSASJ..63..100B. doi:10.2136/sssaj1999.03615995006300010016x.
  25. ^ Ralebitso TK, Senior E, van Verseveld HW (2002). "Microbial aspects of atrazine degradation in natural environments". Biodegradation. 13 (1): 11–19. doi:10.1023/A:1016329628618. PMID 12222950. S2CID 21098999. Archived from the original on 2022-03-15. Retrieved 2019-10-29.
  26. ^ Cai B, Han Y, Liu B, Ren Y, Jiang S (2003). "Isolation and characterization of an atrazine-degrading bacterium from industrial wastewater in China". Letters in Applied Microbiology. 36 (5): 272–276. doi:10.1046/j.1472-765X.2003.01307.x. PMID 12680937. S2CID 8003165.
  27. ^ Pesticide Information Profile: Atrazine Archived 2022-04-01 at the Wayback Machine, 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.
  28. ^ "IARC Monographs evaluation of the carcinogenicity of atrazine, alachlor, and vinclozolin". IARC. November 21, 2025. Retrieved 14 December 2025.
  29. ^ Beane Freeman, Laura E. (2011) Atrazine and Cancer Incidence Among Pesticide Applicators in the Agricultural Health Study (1994–2007) Archived 2012-03-28 at the Wayback Machine. Environmental Health Perspectives.
  30. ^ Renner, Rebecca (May 2008). "Atrazine Effects in Xenopus Aren't Reproducible". Environmental Science & Technology. 42 (10): 3491–3493. Bibcode:2008EnST...42.3491R. doi:10.1021/es087113j. PMID 18546678.
  31. ^ Rohr, Jason R. (2021). "The Atrazine Saga and its Importance to the Future of Toxicology, Science, and Environmental and Human Health". Environmental Toxicology and Chemistry. 40 (6): 1544–1558. Bibcode:2021EnvTC..40.1544R. doi:10.1002/etc.5037. PMID 33999476.
  32. ^ Duhigg, Charles (August 22, 2009). "Debating How Much Weed Killer Is Safe in Your Water Glass". The New York Times. Archived from the original on 2018-11-07. Retrieved 2015-05-02.
  33. ^ Atrazine Updates: Amphibians Archived 2015-09-30 at the Wayback Machine, April 2010, EPA.
  34. ^ Kloas, Werner; Lutz, Ilka; Springer, Timothy; Krueger, Henry; Wolf, Jeff; Holden, Larry; Hosmer, Alan (February 2009). "Does Atrazine Influence Larval Development and Sexual Differentiation in Xenopus laevis?". Toxicological Sciences. 107 (2): 376–384. doi:10.1093/toxsci/kfn232. PMC 2639758. PMID 19008211.
  35. ^ Tillitt DE, Papoulias DM, Whyte JJ, Richter CA (2010). "Atrazine reduces reproduction in fathead minnow (Pimephales promelas)". Aquat. Toxicol. 99 (2): 149–59. Bibcode:2010AqTox..99..149T. doi:10.1016/j.aquatox.2010.04.011. PMID 20471700. Archived from the original on 2022-03-15. Retrieved 2020-09-01.
  36. ^ "Chemical Hazards in Drinking Water - Atrazine" (PDF). Archived (PDF) from the original on 2022-03-15. Retrieved 2015-02-08.
  37. ^ Goodman, M; Mandel, J. S.; Desesso, J. M.; Scialli, A. R. (2014). "Atrazine and pregnancy outcomes: A systematic review of epidemiologic evidence". Birth Defects Research Part B: Developmental and Reproductive Toxicology. 101 (3): 215–36. doi:10.1002/bdrb.21101. PMC 4265844. PMID 24797711.
  38. ^ "Public Health Statement for Atrazine". Agency for Toxic Substances and Disease Registry.
  39. ^ Graymore, M.; Stagnitti, F.; Allinson, G. (2001). "Impacts of atrazine in aquatic ecosystems". Environment International. 26 (7–8): 483–495. Bibcode:2001EnInt..26..483G. doi:10.1016/s0160-4120(01)00031-9. PMID 11485216.
  40. ^ "How the EPA is Ignoring Atrazine Contamination in Surface and Drinking Water in the Central United States" (PDF). Natural Resources Defense Council. The New York Times. August 2009. Archived (PDF) from the original on 2022-04-17. Retrieved 2010-12-19.
  41. ^ Wang, Shoumeng; Yang, Yang; Li, Dongzhi; Xie, Lanfen; Wu, Yanbing; Li, Guangling (2024). "Current Research Status, Opportunities, and Future Challenges of Nine Representative Persistent Herbicides". Journal of Agricultural and Food Chemistry. 72 (40): 21959–21972. Bibcode:2024JAFC...7221959W. doi:10.1021/acs.jafc.4c04537. PMID 39331366.
  42. ^ a b Chemicals in the News: Atrazine, Australian Pesticides and Veterinary Medicines Authority, Original June 30, 2010, Archived by Internet Archive July 4, 2010
  43. ^ Hayes, TB; Khoury, V; Narayan, A; Nazir, M; Park, A; Brown, T; Adame, L; Chan, E; et al. (2010). "Atrazine induces complete feminization and chemical castration in male African clawed frogs (Xenopus laevis)". Proceedings of the National Academy of Sciences of the United States of America. 107 (10): 4612–7. Bibcode:2010PNAS..107.4612H. doi:10.1073/pnas.0909519107. PMC 2842049. PMID 20194757.
  44. ^ European Commission. 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) Archived 15 March 2022 at the Wayback Machine
  45. ^ name=NYT2004>Danny Hakimfeb for the New York Times. February 23, 2015. A Pesticide Banned, or Not, Underscores Trans-Atlantic Trade Sensitivities Archived 2016-12-23 at the Wayback Machine
  46. ^ "Re-evaluation Note REV2017-09, Special Review Decision: Atrazine". Pest Management Regulatory Agency. 31 March 2017. Archived from the original on 5 November 2022. Retrieved 5 November 2022.
  47. ^ City of Greenville v. Syngenta Crop Protection, Inc., and Syngenta AG Case No. 3:10-cv-00188-JPG-PMF Archived 2021-05-06 at the Wayback Machine, accessed August 23, 2013
  48. ^ Clare Howard for Environmental Health News. June 17, 2013 Special Report: Syngenta's campaign to protect atrazine, discredit critics. Archived 2014-03-30 at the Wayback Machine
[edit]
  • Atrazine- PubChem(National library of medicine) - atrazine
  • Atrazine Fact Sheet - National Pesticide Information Center - Atrazine Fact Sheet
  • Atrazine - CDC - NIOSH Pocket Guide to Chemical Hazards
  • Atrazine in the Pesticide Properties DataBase (PPDB)