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Norflurazon (Ref: H 52143)
Last updated: 24/02/2021
(Also known as: norflurazone; H 9789; monometflurazon)

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; Possible 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
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
                 
Also used in
Also used in
Australia
Chemical structure
Isomerism
-
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 group
Pyridazinone
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
8233
US EPA chemical code
105801
PubChem CID
33775
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 Classification (HRAC)
F1
Herbicide Resistance Classification (WSSA)
12
Insecticide Resistance Classification (IRAC)
Not applicable
Fungicide Resistance Classification (FRAC)
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
  • Zorial
  • Solicam
  • Evital
  • Predict
Example products using this active
  • Sandoz
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 (click here )
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
Bulk density (g ml⁻¹)
1.45
Q2 Q = Miscellaneous internet resources
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
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
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 on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ 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)
- - -
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
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 -
Key metabolites
Metabolite
Formation medium
Estimated maximum occurrence fraction
1107/2009 relevancy
desmethyl norflurazon
Soil - -
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
Bio-concentration factor
BCF (l kg⁻¹)
28
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Whole fish
Low potential
CT₅₀ (days)
Not available -
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 year
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)
- - -
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
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
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
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
1.0
P3 P = Other governments and regulators
3 = Unverified data of known source
Daphnia magna
Moderate
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 (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 (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Lemna gibba
Moderate
Non-target plants
- - -
- - -
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 governments and regulators
4 = Verified data
Chlamydomonas reinhardtii
Moderate
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 (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
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
-
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)
- - -
Other soil macro-organisms
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Other arthropod (1)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
Other arthropod (2)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
Soil micro-organisms
- - -
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)
0.02
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
-
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 
Notes
-
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
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
USEPA - possible human carcinogen
Handling issues
Property
Value and interpretation
General
No information available
CLP classification 2013
Environment: H400, H410
EC Risk Classification
Xn - Harmful: R22
Xi - Irritant: R36/38
EC Safety Classification
-
WHO Classification
U (Unlikely to present an acute hazard)
UN Number
-
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
norflurazon
French
norflurazon
German
Norflurazon
Danish
norflurazon
Italian
norflurazon
Spanish
norflurazona
Greek
-
Polish
norflurazon
Swedish
-
Hungarian
-
Dutch
-

Record last updated: 24/02/2021
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