Dimefuron (Ref: RP 23465)	Last updated: 15/01/2023
(Not known by any other names)

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SUMMARY

Dimefuron is a herbicide used for the control of annual broad-leaved weeds. It has a low aqueous solubility and a low volatility. It may be persistent in soil and aquatic systems depending on local conditions. Based on its physico-chemical properties it has potential to leach to groundwater. It is highly toxic to algae, moderately toxic to earthworms but appears to be less toxic to other oransisms for which data is available. Dimefuron has a low oral mammalian toxicity.

Data alerts

The following 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.

Environmental fate	Ecotoxicity	Human health
Environmental fate High alert: Persistent; GUS: High leachability	Ecotoxicity Moderate alert: Earthworms acute ecotoxicity: Moderate	Human health Low alert Warning: Significant data are missing

GENERAL INFORMATION

Description	A herbicide applied pre- and post-emergence to control annual broad-leaved weeds
Example pests controlled	Chickweed; Scented mayweed; Charlock
Example applications	Legumes including peas, beans; Lucerne; Oilseed rape; Cruciferous vegetables
Efficacy & activity	-
Availability status	-
Introduction & key dates	circa 1975

UK regulatory status

UK COPR regulatory status	Not approved
Date COPR inclusion expires	Expired
UK LERAP status	No UK approval for use

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status	Not approved
Dossier rapporteur/co-rapporteur	Not applicable
Date EC 1107/2009 inclusion expires	Expired
EU Candidate for substitution (CfS)	-
Listed in EU database	Yes
Approved for use (✓) under EC 1107/2009 in the following EU Member States	ATAustria BEBelgium BGBulgaria CYCyprus CZCzech Republic DEGermany DKDenmark EEEstonia ELGreece                   ESSpain FIFinland FRFrance HRCroatia HUHungary IEIreland ITItaly LTLithuania LULuxembourg                   LVLatvia MTMalta NLNetherlands PLPoland PTPortugal RORomania SESweden SISlovenia SKSlovakia

Additional information

Also used in	-

Chemical structure

Isomerism	None
Chemical formula	C₁₅H₁₉ClN₄O₃
Canonical SMILES	CC(C)(C)C1=NN(C(=O)O1)C2=C(C=C(C=C2)NC(=O)N(C)C)Cl
Isomeric SMILES	No data
International Chemical Identifier key (InChIKey)	DHWRNDJOGMTCPB-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C15H19ClN4O3/c1-15(2,3)12-18-20(14(22)23-12)11-7-6-9(8-10(11)16)17-13(21)19(4)5/h6-8H,1-5H3,(H,17,21)
2D structure diagram/image available?	Yes

General status

Pesticide type	Herbicide
Substance groups	Oxadiazolone herbicide; Phenylurea herbicide
Minimum active substance purity	-
Known relevant impurities	-
Substance origin	Synthetic
Mode of action	Selective, absorbed mainly through the roots. Photosystem II inhibitor.
CAS RN	34205-21-5
EC number	251-879-4
CIPAC number	279
US EPA chemical code	-
PubChem CID	91612
CLP index number	No data found
Molecular mass	338.79
PIN (Preferred Identification Name)	N'-[4-(5-tert-butyl-2-oxo-1,3,4-oxadiazol-3(2H)-yl)-3-chlorophenyl]-N,N-dimethylurea
IUPAC name	3-[4-(5-tert-butyl-2,3-dihydro-2-oxo-1,3,4-oxadiazol-3-yl)-3-chlorophenyl]-1,1-dimethylurea
CAS name	N'-[3-chloro-4-[5-(1,1-dimethylethyl)-2-oxo-1,3,4-oxadiazol-3(2H)-yl]phenyl]-N,N-dimethylurea
Other status information	PAN Listed as Highly Hazardous Chemical
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Classification (HRAC)	C2
Herbicide Resistance Classification (WSSA)	7
Insecticide Resistance Classification (IRAC)	Not applicable
Fungicide Resistance Classification (FRAC)	Not applicable
Examples of recorded resistance	-
Physical state	Colourless crystals

Formulations

Property	Value
Example manufacturers & suppliers of products using this active now or historically	-
Example products using this active	Pradone
Formulation and application details	-

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C (mg l⁻¹)		16	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes	Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)		-	-	-
Melting point (°C)		193	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
Boiling point (°C)		-	-	-
Degradation point (°C)		-	-	-
Flashpoint (°C)		-	-	-
Octanol-water partition coefficient at pH 7, 20 °C	P	3.24 X 1002	Calculated	-
	Log P	2.51	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes	Low
Fat solubility of residues	Solubility	-	-	-
	Data type	-	-	-
Density (g ml⁻¹)		1.3	Q2 Q = Miscellaneous internet resources 2 = Unverified data of unknown source	-
Dissociation constant pKa) at 25 °C		Not applicable	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes	-
		No dissociation
Vapour pressure at 20 °C (mPa)		0.01	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes	Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		2.12 X 10-03	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Non-volatile
Maximum UV-vis absorption L mol⁻¹ cm⁻¹		-	-	-
Surface tension (mN m⁻¹)		-	-	-

Degradation

Property		Value	Source; quality score; and other information	Interpretation
General biodegradability		-
Soil degradation (days) (aerobic)	DT₅₀ (typical)	65	B4 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 4 = Verified data	Moderately persistent
	DT₅₀ (lab at 20 °C)	129	B4 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 4 = Verified data	Persistent
	DT₅₀ (field)	-	-	-
	DT₉₀ (lab at 20 °C)	-	-	-
	DT₉₀ (field)	-	-	-
	DT₅₀ modelling endpoint	-	-	-
	Note	Lab studies DT₅₀ range 100-203 days
Dissipation rate RL₅₀ on plant matrix	Value	-	-	-
	Note	-
Dissipation rate RL₅₀ on and in plant matrix	Value	-	-	-
	Note	-
Aqueous photolysis DT₅₀ (days) at pH 7	Value	-	-	-
	Note	-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7	Value	226	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes	Persistent
	Note	-
Water-sediment DT₅₀ (days)		97	Q3 Q = Miscellaneous internet resources 3 = Unverified data of known source	Moderately fast
Water phase only DT₅₀ (days)		82	Q3 Q = Miscellaneous internet resources 3 = Unverified data of known source	Stable

Soil adsorption and mobility

Property		Value	Source; quality score; and other information	Interpretation
Linear	Kd	-	-	-
	Koc	-
	Notes and range	-
Freundlich	Kf	2.54	B4 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 4 = Verified data	Moderately mobile
	Kfoc	206
	1/n	0.91
	Notes and range	-
pH sensitivity		-

Fate indices

Property		Value	Source; quality score; and other information	Interpretation
GUS leaching potential index		3.56	Calculated	High leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate	Value	7.07 X 10-01	Calculated	-
	Note	-
Potential for particle bound transport index		Medium	Calculated	-
Potential for loss via drain flow		Moderately mobile	Calculated	-
Bio-concentration factor	BCF (l kg⁻¹)	Low risk	Q3 Q = Miscellaneous internet resources 3 = Unverified data of known source Based on LogP < 3	Low risk
	CT₅₀ (days)	-		-

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property		Value	Source; quality score; and other information	Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		> 2000	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes Rat	Low
Mammals - Short term dietary NOEL	(mg kg⁻¹)	15.5	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes Rat	High
	(ppm diet)	250		-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Birds - Acute LD₅₀ (mg kg⁻¹)		3350	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes Colinus virginianus	Low
Birds - Short term dietary (LC₅₀/LD₅₀)		-	-	-
Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)		300	Q3 Q = Miscellaneous internet resources 3 = Unverified data of known source	Moderate
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)		-	-	-
Soil micro-organisms		-	-	-
Collembola	Acute LC₅₀ (mg kg⁻¹)	-	-	-
	Chronic NOEC (mg kg⁻¹)	-	-	-
Non-target plants		-	-	-
		-	-	-
Honeybees (Apis spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	500	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes	Low
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
	Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
	Chronic	-	-	-
Bumblebees (Bombus spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
		-
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
		-
Mason bees (Osmia spp.)	Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
	Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)	-	-	-
Other pollinators (1)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Other pollinators (2)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Beneficial insects (Ladybirds)		-	-	-
Beneficial insects (Lacewings)		-	-	-
Beneficial insects (Parasitic wasps)		-	-	-
Beneficial insects (Predatory mites)		-	-	-
Beneficial insects (Ground beetles)		-	-	-

Aquatic ecotoxicology

Property		Value	Source; quality score; and other information	Interpretation
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		1000	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes Lepomis macrochirus	Low
Fish - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		575	K3 K = Research datasets, e.g. Pandora, Demetra 3 = Unverified data of known source Unknown species	Low
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)		-	-	-
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)		-	-	-
Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)		-	-	-
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)		0.008	K2 K = Research datasets, e.g. Pandora, Demetra 2 = Unverified data of unknown source Unknown species	High
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)		-	-	-
Mesocosm study data	NOEAEC mg l⁻¹	-	-	-
	NOEAEC mg l⁻¹	-	-	-

HUMAN HEALTH AND PROTECTION

General

Property		Value	Source; quality score; and other information	Interpretation
Threshold of Toxicological Concern (Cramer Class)		High (class III)	-	-
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		> 2000	B5 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 5 = Verified data used for regulatory purposes Rat	Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)		2000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat	-
Mammals - Inhalation LC₅₀ (mg l⁻¹)		-	-	-
Other Mammal toxicity endpoints		-	-	-
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)		0.07	B4 B = UK CRD and ACP evaluation documents / and other Defra (UK) documents (click here ) 4 = Verified data UK ACP 1999	-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)		-	-	-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)		-	-	-
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)		-	-	-
Dermal penetration studies (%)		-	-	-
Dangerous Substances Directive 76/464		-	-	-
Exposure Routes	Public	-
	Occupational	-
MRLs	European	EU MRL pesticide database
	Great Britain	GB MRL Register
	Notes	-
Drinking Water Standards		-	-	-
Drinking Water MAC (μg l⁻¹)		-	-	-
Mammalian dose elimination route and rate		-	-	-

Health issues

Specific human health issues		Carcinogen Genotoxic Endocrine disruptor No data found A3 A = Chromosome aberration (EFSA database) 3 = Negative ; B3 B = DNA damage/repair (EFSA database) 3 = Negative ; C3 C = Gene mutation (EFSA database) 3 = Negative ; D0 D = Genome mutation (EFSA database) 0 = No data ; E0 E = Unspecified genotoxicity type (miscellaneous data source) 0 = No data No data found Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant No data found XNo, known not to cause a problem No data found Respiratory tract irritant Skin irritant Skin sensitiser No data found No data found No data found Eye irritant Phototoxicant   No data found No data found
General human health issues		No further information avilable

Handling issues

Property	Value and interpretation
General	No information avilable
CLP classification 2013	Health: H302
WHO Classification	III (Slightly hazardous)
UN Number	-
Waste disposal & packaging	-

TRANSLATIONS

Language	Name
English	dimefuron
French	diméfuron
German	Dimefuron
Danish	dimefuron
Italian	dimefuron
Spanish	dimefuron
Greek	-
Polish	dimefuron
Swedish	-
Hungarian	-
Dutch	-

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Record last updated:	15/01/2023
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