| Imazamox ammonium |
![]() Last updated: 01/03/2026 |
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(Not known by any other names) |
| SUMMARY |
| Hazard alerts |
The following Pesticide Hazard Tricolour (PHT) alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement. The alerts for Highly Hazardous Pesticides (HHPs) are based on applying the FAO/WHO (Type 1) and the PAN (Type II) criteria to PPDB data. Further details on the HHP indicators are given in the tables below. Neither the PHT nor the HHP hazard alerts take account of usage patterns or exposure, thus they do not represent risk.
| PHT: Environmental fate | PHT: Ecotoxicity | PHT: Human health | Highly Hazardous Pesticide |
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A post-emergence herbicide used to control weeds including those in aquatic situations | |
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Grass and broadleaved weeds; Common reed (Phragmites australis); Flowering rush (Butomus umbellatus); Curly-leaf pond weed (Potamogeton crispus) | |
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Aquatic situations; Edible legumes; Soybeans; Alfalfa; Sunflowers; Winter OSR | |
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| GB regulatory status |
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Approved | ||
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31/01/2029 | ||
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Check label - may vary with formulation |
| EC Regulation 1107/2009 (repealing 91/414) |
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Approved (as imazamox) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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France/Italy | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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30/06/2027 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Yes - two 'Persistent-Bioaccumulative-Toxic' criteria | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Yes | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Additional information |
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Australia; Morocco; Japan |
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| Chemical structure |
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The core molecule, imazamox exhibits optical isomerism due to a single chiral centre located at the 4-position of the imidazolinone ring, resulting in a pair of enantiomers: (R)-imazamox and (S)-imazamox. Commercially available imazamox, including its ammonium salt, is supplied as a racemic mixture. The ammonium cation (NH₄⁺) in the salt form pairs with the deprotonated carboxylate group of imazamox, but it does not introduce additional chirality or alter the stereogenic centre in the organic anion; thus, the isomerism remains identical to that of the parent acid. | |
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C₁₅H₂₂N₄O₄ | |
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InChI=1S/C15H19N3O4.H3N/c1-8(2)15(3)14(21)17-12(18-15)11-10(13(19)20)5-9(6-16-11)7-22-4;/h5-6,8H,7H2,1-4H3,(H,19,20)(H,17,18,21);1H3 | |
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GNZZHGJSMCDMBU-UHFFFAOYSA-N | |
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Yes |
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| Common Name | Relationship | Link |
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| imazamox ammonium | R-isomer | ![]() |
| imazamox ammonium | - | ![]() |
| General status |
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Herbicide | ||||||||||||||
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Imidazolinone herbicide | ||||||||||||||
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Synthetic | ||||||||||||||
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Contact and residual activity. Inhibits plant amino acid synthesis - acetohydroxyacid synthase AHAS. | ||||||||||||||
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247057-22-3 | ||||||||||||||
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rac-ammonium 5-(methoxymethyl)-2-[(4R)-4-methyl-5-oxo-4-(propan-2-yl)-4,5-dihydro-1H-imidazol-2-yl]pyridine-3-carboxylate | ||||||||||||||
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ammonium 2-[(RS)-4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl]-5-methoxymethylnicotinate | ||||||||||||||
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ammonium 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-(methoxymethyl)-3-pyridinecarboxylate | ||||||||||||||
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Not applicable | ||||||||||||||
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Not applicable | ||||||||||||||
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Avena fatua, Lolium rigidum, Amaranthus retroflexus | ||||||||||||||
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| Commercial |
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Current | |||
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2001, imazamox introduced | |||
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Usually supplied as a liquid concentrate | |||
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The industrial synthesis of imazamox begins with the construction of its imidazolinone core, typically through condensation reactions involving pyridine carboxylic acid derivatives and imidazolinone intermediates. The process includes key steps such as cyclization to form the heterocyclic ring and selective substitution to introduce functional groups that enhance herbicidal activity. The resulting imazamox acid is then converted to the more soluble ammonium salt form by reacting it with ammonia or ammonium hydroxide in an aqueous medium, typically under controlled conditions to achieve complete neutralisation of the carboxylic acid group (pKa-relevant deprotonation), yielding the ammonium imazamox salt. | |||
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Insoluble | A4 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 4 = Verified data |
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Regulatory data | A4 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 4 = Verified data |
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| Degradation |
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As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below. | ||||||||||
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| Fate indices |
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Cannot be calculated | - | - | |||||||||||||||||||||||||
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| Known soil metabolites |
None
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None
| Other known metabolites |
None
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| Terrestrial ecotoxicology |
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> 5000 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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> 1068 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat 2-yr as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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> 1846 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Colinus virginianus as imazamox5 = Verified data used for regulatory purposes |
Moderate | ||||||||
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> 1934 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Anas platyrhynchos as imazamox5 = Verified data used for regulatory purposes |
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209.4 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Colinus virginianus NOAEL as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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> 901 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Eisenia foetida as imazamox5 = Verified data used for regulatory purposes |
Moderate | ||||||||
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5.85 | A4 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Eisenia foetida as imazamox4 = Verified data |
Moderate | ||||||||
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Nitrogen mineralisation: No significant adverse effect Carbon mineralisation: No significant adverse effect |
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) 5 = Verified data used for regulatory purposes Dose: 0.15 kg imazamox/ha |
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4.74 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Folsomia candida as imazamox5 = Verified data used for regulatory purposes |
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> 58 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Apis mellifera as imazamox5 = Verified data used for regulatory purposes |
Moderate | |||||||
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> 40 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Apis mellifera as imazamox5 = Verified data used for regulatory purposes |
Moderate | ||||||||
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> 437.5 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Aphidius rhopalosiphi as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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> 335 | A4 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Typhlodromus pyri as imazamox4 = Verified data |
Low | ||||||||
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> 335 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Poecilus cupreus as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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| Aquatic ecotoxicology |
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> 122 | F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment ) Oncorhynchus mykiss as imazamox4 = Verified data |
Low | ||||||||
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0.03 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Lemna gibba as imazamox5 = Verified data used for regulatory purposes |
Moderate | ||||||||
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> 100 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Myriophyllum aquaticum as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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28.1 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Raphidocelis subcapitata as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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5.1 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Raphidocelis subcapitata as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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| Regulatory Threshold Levels (RTLs) |
Note: These RTLs have been calculated using the regulatory approach used in the European Union and based on ecotoxocity values in the PPDB.
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213.6 | Worst case of acute and chronic mammals | |||
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41.88 | Worst case of acute and chronic birds | |||
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1.17 | Worst case of acute and chronic earthworms | |||
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No data | No data for non-target plants vegetative vigour and seedling emergence | |||
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0.8 | Worst case of contact and oral honeybees | |||
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167.5 | Worst case of parasitic wasps and predatory mites | |||
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1.22 | Worst case of temperate acute and chronic fish | |||
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No data | No data for temperate acute and chronic aquatic invertebrates | |||
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0.003 | Worst case of free-floating plants, rooted plants, acute and chronic algae |
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| General |
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High (class III) | - | - | ||||||||
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> 5000 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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> 1068 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat 2-yr as imazamox5 = Verified data used for regulatory purposes |
Low | ||||||||
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> 4000 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) Rat as imazamox5 = Verified data used for regulatory purposes |
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3.0 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) as imazamox5 = Verified data used for regulatory purposes |
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3.0 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) as imazamox5 = Verified data used for regulatory purposes |
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2.25 | A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications ) as imazamox5 = Verified data used for regulatory purposes |
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No unacceptable risks to bystanders identified | |||||||||
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No unacceptable risks to operators or other workers indentified | ||||||||||
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No further information available | ||||||||||||||||||||||||||||
| Handling issues |
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Prevent generation of mists Not explosive or oxidising IMDG Transport Hazard Class 9 Not expected to auto-ignite; Not highly flammable |
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Environment: H400, H410 | |||
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III (Slightly hazardous) | |||
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UN3077 | |||
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Packaging Group III (minor danger) | |||
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imazamox ammonium | ||
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| Record last updated: | 01/03/2026 |
| Contact: | aeru@herts.ac.uk |
| Please cite as: | Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242 |
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