Norflurazon (Ref: H 52143)	Last updated: 05/02/2024
(Also known as: norflurazone; H 9789; monometflurazon)

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SUMMARY

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: Fish acute ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate	Human health Moderate alert: Possible Carcinogen; Reproduction/development effects

GENERAL INFORMATION

Description	A pre-emergence herbicide used to control germinating weeds in various cropping, non-agricultural and industrial situations
Example pests controlled	Grasses; Sedges; Broad-leaved weeds
Example applications	Fruit; Vegetables; Nuts; Cotton; Peanuts; Soybeans
Efficacy & activity	-
Availability status	Current
Introduction & key dates	1968, introduced

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
Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries	ISIceland NONorway

Additional information

Also used in	Australia

Chemical structure

Isomerism	None
Chemical formula	C₁₂H₉ClF₃N₃O
Canonical SMILES	CNC1=C(C(=O)N(N=C1)C2=CC=CC(=C2)C(F)(F)F)Cl
Isomeric SMILES	No data
International Chemical Identifier key (InChIKey)	NVGOPFQZYCNLDU-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C12H9ClF3N3O/c1-17-9-6-18-19(11(20)10(9)13)8-4-2-3-7(5-8)12(14,15)16/h2-6,17H,1H3
2D structure diagram/image available?	Yes

General status

Pesticide type	Herbicide
Substance groups	Pyridazinone herbicide
Minimum active substance purity	-
Known relevant impurities	-
Substance origin	Synthetic
Mode of action	Selective, absorbed by roots and translocated. Bleaching: inhibition of carotenoid biosynthesis.
CAS RN	27314-13-2
EC number	248-397-1
CIPAC number	None allocated
US EPA chemical code	105801
PubChem CID	33775
CLP index number	No data found
Molecular mass	303.7
PIN (Preferred Identification Name)	-
IUPAC name	4-chloro-5-methylamino-2-(α,α,α-trifluoro-m-tolyl)pyridazin-3(2H)-one
CAS name	4-chloro-5-(methylamino)-2-(3-(trifluoromethyl)phenyl)-3(2H)-pyridazinone
Other status information	Potential groundwater contaminant
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Class (HRAC MoA class)	F1
Herbicide Resistance Class (WSSA MoA class)	12
Insecticide Resistance Class (IRAC MoA class)	Not applicable
Fungicide Resistance Class (FRAC MOA class)	Not applicable
Examples of recorded resistance	-
Physical state	White to greyish-brown crystalline powder

Formulations

Property	Value
Example manufacturers & suppliers of products using this active now or historically	Sandoz
Example products using this active	Zorial Solicam Evital Predict
Formulation and application details	Available in a variety of formulations including wettable powders, flowable concentrates and granules

ENVIRONMENTAL FATE

Property		Value	Source; quality score; and other information	Interpretation
Solubility - In water at 20 °C (mg l⁻¹)		34	H4 H = The US ARS pesticide properties database. Dataset is no longer available. 4 = Verified data	Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)		142000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Ethanol	-
		50000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Acetone	-
		2500	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Xylene	-
Melting point (°C)		177	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	2.82 X 1002	Calculated	-
	Log P	2.45	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Low
Fat solubility of residues	Solubility	-	-	-
	Data type	-	-	-
Density (g ml⁻¹)		1.45	Q2 Q = Miscellaneous data from online sources 2 = Unverified data of unknown source	-
Dissociation constant pKa) at 25 °C		Not applicable	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	-
		No dissociation
Vapour pressure at 20 °C (mPa)		3.86 X 10-03	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)		3.50 X 10-05	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Non-volatile
Volatilisation as max % of applied dose lost	From plant surface	-	-	-
	From soil surface	-	-	-
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)	90	W4 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available. 4 = Verified data	Moderately persistent
	DT₅₀ (lab at 20 °C)	-	-	-
	DT₅₀ (field)	225	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source	Persistent
	DT₉₀ (lab at 20 °C)	-	-	-
	DT₉₀ (field)	-	-	-
	DT₅₀ modelling endpoint	-	-	-
	Note	Literature field studies DT₅₀ range 3-9 months USA
Dissipation rate RL₅₀ (days) on plant matrix	Value	-	-	-
	Note	-
Dissipation rate RL₅₀ (days) on and in plant matrix	Value	12.4	R4 R = Peer reviewed scientific publications 4 = Verified data	-
	Note	Published literature RL₅₀ range 9.0-15.9 days, 2 field crops, various matrices, n=2
Aqueous photolysis DT₅₀ (days) at pH 7	Value	-	-	-
	Note	-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7	Value	-	-	-
	Note	-
Water-sediment DT₅₀ (days)		-	-	-
Water phase only DT₅₀ (days)		-	-	-
Air degradation		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.

Soil adsorption and mobility

Property		Value	Source; quality score; and other information	Interpretation
Linear	Kd	-	W3 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available. 3 = Unverified data of known source	Slightly mobile
	Koc	700
	Notes and range	-
Freundlich	Kf	10.7	R4 R = Peer reviewed scientific publications 4 = Verified data	Moderately mobile
	Kfoc	295
	1/n	1.303
	Notes and range	Literature data: Kf range 0.35-93.02 mL g⁻¹, Kfoc range 42-578 mL g⁻¹, 1/n range 0.87-1.64, Soils=17
pH sensitivity		-

Fate indices

Property		Value	Source; quality score; and other information	Interpretation
GUS leaching potential index		3.60	Calculated	High leachability
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate	Value	7.68 X 10-01	Calculated	-
	Note	-
Potential for particle bound transport index		Medium	Calculated	-
Potential for loss via drain flow		Slightly mobile	Calculated	-
Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk		-	-	-
Bio-concentration factor	BCF (l kg⁻¹)	28	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 ) 4 = Verified data Whole fish	Low potential
	CT₅₀ (days)	Not available		-

Known soil metabolites

Metabolite	Major/Minor fraction	Estimated maximum occurrence fraction	Notes
desmethyl norflurazon	-	-	-

Known groundwater metabolites

None

Other known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property		Value	Source; quality score; and other information	Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)		> 5000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat	Low
Mammals - Short term dietary NOEL	(mg kg⁻¹)	19	L2 L = Pesticide manuals and hard copy reference books / other sources 2 = Unverified data of unknown source Rat 2 yr	High
	(ppm diet)	-		-
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)		-	-	-
Birds - Acute LD₅₀ (mg kg⁻¹)		> 2150	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Anas platyrhynchos	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)		1000	L3 L = Pesticide manuals and hard copy reference books / other sources 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)	> 236	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 ) 4 = Verified data Apis mellifera	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)	235	L2 L = Pesticide manuals and hard copy reference books / other sources 2 = Unverified data of unknown source	Low
	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 bee species (1)	Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)	-	-	-
	Mode of exposure	-
Other bee species (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
Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		> 8.1	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Oncorhynchus mykiss	Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)		-	-	-
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)		-	-	-
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		> 15	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Daphnia magna	Moderate
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)		1.0	P3 P = Other non-EU, UK or US Governments and Regulators 3 = Unverified data of known source Daphnia magna	Moderate
Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)		-	-	-
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)		> 2.29	F3 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 ) 3 = Unverified data of known source Americamysis bahia	Moderate
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)		0.086	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 ) 4 = Verified data Lemna gibba	Moderate
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)		> 0.0176	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Raphidocelis subcapitata	Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)		> 0.38	P4 P = Other non-EU, UK or US Governments and Regulators 4 = Verified data Chlamydomonas reinhardtii	Moderate
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)		> 5000	L3 L = Pesticide manuals and hard copy reference books / other sources 3 = Unverified data of known source Rat	Low
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)		5000	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)		-	-	-
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 ?Possibly, status not identified A3 A = Chromosome aberration (EFSA database) 3 = Negative ; B0 B = DNA damage/repair (EFSA database) 0 = No data ; C0 C = Gene mutation (EFSA database) 0 = No data ; 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 ?Possibly, status not identified XNo, known not to cause a problem XNo, known not to cause a problem Respiratory tract irritant Skin irritant Skin sensitiser XNo, known not to cause a problem ✓Yes, known to cause a problem XNo, known not to cause a problem Eye irritant Phototoxicant   ✓Yes, known to cause a problem No data found
General human health issues		Possible liver toxicant Harmful if swallowed US EPA - possible human carcinogen

Handling issues

Property	Value and interpretation
General	No information available
CLP classification 2013	Environment: H400, H410
WHO Classification	U (Unlikely to present an acute hazard)
UN Number	-
Waste disposal & packaging	-
Shelf-life, storage, stability and reactivity	-

TRANSLATIONS

Language	Name
English	norflurazon
French	norflurazon
German	Norflurazon
Danish	norflurazon
Italian	norflurazon
Spanish	norflurazona
Greek	-
Polish	norflurazon
Swedish	-
Hungarian	-
Dutch	-
Norwegian	-

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Record last updated:	05/02/2024
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