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Diclofop (Ref: AE F021079)
(Also known as: diclofop acid; diclofop free acid; HOE 021079)
SUMMARY
Diclofop is a grass herbicide which is usually used as the methyl variant. It is highly soluble in water and is not considered to be volatile. It is not normally environmentally persistent. Diclofop is moderately toxic to mammals via the oral route. Its toxicity to biodiversity tends to be moderate to low.
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
Moderate alert:
Moderately persistent; GUS: Transition state; Drainflow: Moderately mobile
Ecotoxicity
Moderate alert:
Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate
Human health
Moderate alert:
Mammals acute toxicity: Moderate; Possible Carcinogen; Possible Reproduction/development effects
GENERAL INFORMATION
Description
Post-emergence herbicide usually used as the methyl variant. Also a pesticide transformation product
Example pests controlled
Wild oats; Crowsfoot grass; Annual ryegrass; Common barbgrass
Example applications
Vegetables including brassicas, beans, carrots, peas, parsnips, onions; Sugarbeet; Cereals including barley, wheat; Oilseed rape; Potatoes
Efficacy & activity
-
Availability status
Current
Introduction & key dates
circa 1982
UK regulatory status
UK COPR regulatory status
Approved
Date COPR inclusion expires
31/05/2026
UK LERAP status
None
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Approved
Dossier rapporteur/co-rapporteur
Portugal/France
Date EC 1107/2009 inclusion expires
31/05/2023
EU Candidate for substitution (CfS)
Yes - low ADI / ARfD / AOEL
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
-
Chemical structure
Isomerism
A chiral molecule. Substance is racemic.
Chemical formula
C₁₅H₁₂Cl₂O₄
Canonical SMILES
CC(C(=O)O)OC1=CC=C(C=C1)OC2=C(C=C(C=C2)Cl)Cl
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
OOLBCHYXZDXLDS-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C15H12Cl2O4/c1-9(15(18)19)20-11-3-5-12(6-4-11)21-14-7-2-10(16)8-13(14)17/h2-9H,1H3,(H,18,19)
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
diclofop-methyl Variant
General status
Pesticide type
Herbicide, Metabolite
Metabolite Type
Soil
Substance groups
Aryloxyphenoxypropionate herbicide
Minimum active substance purity
930 g kg⁻¹
Known relevant impurities
EU dossier - None declared
Substance origin
Synthetic
Mode of action
Selective, absorbed by leaves and inhibits fatty acid synthesis. Inhibition of acetyl CoA carboxylase (ACCase)
CAS RN
40843-25-2
EC number
No data found
CIPAC number
358
US EPA chemical code
110902
PubChem CID
38687
CLP index number
607-165-00-3
Molecular mass
327.16
PIN (Preferred Identification Name)
rac-(2R)-2-[4-(2,4-dichlorophenoxy)phenoxy]propanoic acid
IUPAC name
(RS)-2-[4-(2,4-dichlorophenoxy)phenoxy]propionic acid
CAS name
2-[4-(2,4-dichlorophenoxy)phenoxy]propanoic acid
Other status information
-
Relevant Environmental Water Quality Standards
-
Herbicide Resistance Classification (HRAC)
A
Herbicide Resistance Classification (WSSA)
1
Insecticide Resistance Classification (IRAC)
Not applicable
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
-
Physical state
Pale yellow solid
Related substances & organisms
Can be a metabolite of:
Parent
Formation medium
Estimated maximum occurrence fraction
1107/2009 relevancy
diclofop-methyl Soil 0.87 Major fraction
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Bayer CropScience
  • Bayer Environmental
Example products using this active
  • Hoe-Grass
  • Hoelon 3EC
  • Illoxan
  • One-shot
Formulation and application details
Usually supplied as an emulsion that is mixed with water and used as a spray
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
122700
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
 High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
- - -
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
4.07 X 1001 Calculated -
Log P
1.61
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)
1.4
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Dissociation constant pKa) at 25 °C
3.43
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Weak acid
Vapour pressure at 20 °C (mPa)
2.5 X 10-03
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 )
5 = Verified data used for regulatory purposes
 Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
- - -
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)
24
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
 Non-persistent
DT₅₀ (lab at 20 °C)
23.9
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
 Non-persistent
DT₅₀ (field)
35.2
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
 Moderately persistent
DT₉₀ (lab at 20 °C)
84.7
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
 Moderately persistent
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
EU dossier lab studies DT₅₀ range 5.1-74.0 days, DT₉₀ range 23.3-246 days, Field studies DT₅₀ range 25.7-52.2 days ; General literature DT₅₀ range 10 days (sand) - 30 days (sandy clay)
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
- - -
Note
-
Water-sediment DT₅₀ (days)
58.3
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
 Moderately fast
Water phase only DT₅₀ (days)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
- - -
Koc
-
Notes and range
-
Freundlich
Kf
6.3
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
 Moderately mobile
Kfoc
289
1/n
0.882
Notes and range
EU dossier kf range 0.76-13.54 mL g⁻¹, kfoc range 148-505.5 mL g⁻¹, 1/n range 0.819-0.913, Soils=6
pH sensitivity
Yes
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
2.38 Calculated Transition state
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
1.24 X 10-01 Calculated -
Note
-
Potential for particle bound transport index
Low Calculated -
Potential for loss via drain flow
Moderately mobile Calculated -
Bio-concentration factor
BCF (l kg⁻¹)
Low risk
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
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)
> 586
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat		 Moderate
Mammals - Short term dietary NOEL
(mg kg⁻¹)
- - -
(ppm diet)
- -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
> 10000
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Phasianidae		 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)
> 500
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
Eisenia foetida corr		 Moderate
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
50
A3 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 )
3 = Unverified data of known source
Eisenia foetida corr		 Moderate
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)
> 100
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
as methyl variant		 Low
Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)
> 131
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
as methyl variant		 Low
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 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
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
> 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 )
5 = Verified data used for regulatory purposes
Oncorhynchus mykiss		 Low
Fish - Chronic 21 day NOEC (mg l⁻¹)
16.0
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 )
5 = Verified data used for regulatory purposes
Oncorhynchus mykiss		 Low
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
48
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
Daphnia magna		 Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
0.0156
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
Daphnia magna		 Moderate
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)
10
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
Chironomus riparius		 Moderate
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)
10.4
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
Pseudokirchneriella subcapitata		 Low
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)
> 586
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat		 Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
- - -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
0.001
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
 -
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
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 )
5 = Verified data used for regulatory purposes
 -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)
- - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)
0.003
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
 -
Dermal penetration studies (%)
- - -
Dangerous Substances Directive 76/464
- - -
Exposure Routes
Public
-
Occupational
Readily absorbed through the gastrointestinal tract
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
A0 A = Chromosome aberration (EFSA database)
0 = No data
;
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
;
E3 E = Unspecified genotoxicity type (miscellaneous data source)
3 = Negative
 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
No data found
?Possibly, status not identified
?Possibly, status not identified
Eye irritant Phototoxicant  
No data found No data found  
General human health issues
Kidney and liver toxicant
Handling issues
Property
Value and interpretation
General
Not explosive or oxidising
CLP classification 2013
Health: H302, H317
Environment: H400, H410
WHO Classification
III (Slightly hazardous)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
diclofop
French
-
German
-
Danish
-
Italian
-
Spanish
-
Greek
-
Polish
dichlofop
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-
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