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2,4-D (Ref: L 208)
** 2,4 PA ** 2,4-dichlorophenoxyacetic acid ** aqualin ** hedonal ** Translations

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SUMMARY

2,4-D is a selective, systemic herbicide approved for use in the EU and used for the control of broad-leaved weeds. It is highly soluble in water, volatile and has a low potential to leach to groundwater based on its chemical properties. It is non-persistent in soil but may persist in aquatic systems under certain conditions. It is moderately toxic to mammals but should not bioaccumulate. It may have negeative effects on reproduction, development and is considered to be a neurotoxin and an irritant. It is moderately toxic to birds and most aquatic species as well as honeybees and earthworms.

GENERAL INFORMATION Click here for an explantaion of the general chemical status information
for 2,4-D

Description: A translocated phenoxy herbicide for use in cereals, grass and amenity use. Can also be a pesticide transformation product

Example pests controlled: Broad-leaved weeds, Evasive weeds in aquatic situations

Example applications: Turf grass & pastures; Non-cropping situations; Amenity sites; Orchards; Cereals including barley, wheat and oats; Lucerne

Efficacy & activity: -

Availability status: Current

Introduction & key dates: circa 1950

EC Regulation 1107/2009 (repealing 91/414):
Status Approved
Dossier rapporteur/co-rapporteur Greece/Poland
Date inclusion expires 31/12/2030
EU Candidate for substitution (CfS) No
Listed in EU database Yes

Approved for use () or known to be used () in the following European countries: Click to access a note on the approvals information on this site

AT

BE

BG

CY

CZ

DE

DK

EE

EL

ES

FI

FR

HR

HU

IE

IT

LT

LU

LV

MT

NL

PL

PT

RO

SE

SI

SK

UK

Also used in: Australia, USA

Chemical structure: Click here for further information on the general chemical status information used on this site
Isomerism None
Chemical formula C8H6Cl2O3
Canonical SMILES C1=CC(=C(C=C1Cl)Cl)OCC(=O)O
Isomeric SMILES No data
International Chemical Identifier key (InChIKey) OVSKIKFHRZPJSS-UHFFFAOYSA-N
International Chemical Identifier (InChI) InChI=1S/C8H6Cl2O3/c9-5-1-2-7(6(10)3-5)13-4-8(11)12/h1-3H,4H2,(H,11,12)
2D structure diagram/image available? Yes

General status: Click here for further information on the general chemical status information used on this site
Pesticide type Herbicide, Plant growth regulator, Metabolite
Metabolite Type Soil
Substance group Alkylchlorophenoxy
Minimum active substance purity 960 g/kg
Known relevant impurities EU dossier - dioxins & furans; 2,4-dichlorophenol
Substance origin Synthetic
Mode of action Selective, systemic, absorbed through roots and increases biosynthesis and production of ethylene causing uncontrolled cell division and so damages vascular tissue. Synthetic auxin.
CAS RN 94-75-7
EC number 202-361-1
CIPAC number 1
US EPA chemical code 030001
PubChem CID 1486
Molecular mass (g mol-1) 221.04
PIN (Preferred Identification Name) (2,4-dichlorophenoxy)acetic acid
IUPAC name (2,4-dichlorophenoxy)acetic acid
CAS name (2,4-dichlorophenoxy)acetic acid
Other status information Potential groundwater contaminant
Relevant Environmental Water Quality Standards UK statutory standard for protection of aquatic life for inland, coastal & territorial surface waters as annual average: 40 ug/L
Herbicide Resistance Classification (HRAC) O
Herbicide Resistance Classification (WSSA) 4
Insecticide Resistance Classification (IRAC) Not applicable
Fungicide Resistance Classification (FRAC) Not applicable
Examples of recorded resistance Limnocharis flava
Limnophila erecta
Papaver rhoeas
Sisymbrium orientale
Physical state White powdery solid
Related substances & organisms

Can be a metabolite of:
Parent Formation medium Estimated maximum occurrence fraction 1107/2009 relevancy Click here for further information on 1107/2009 relevancy
2,4-DB Soil   0.261   Major fraction, Relevancy unknown
2,4-D-dimethylammonium     -
2,4-DEP Soil     -

Formulations:
Property Click here for information on the general product and branding information used on this site Value
Example manufacturers & suppliers of products using this active now or historically
  • AgriChem
  • Dow AgroSciences
  • Headland
  • Nufarm
  • Vitax
Example products using this active
  • Depitox
  • Esteem
  • Weed B Gone
  • Killex
  • Junction
  • Tordon 101
  • Herboxone
  • Polo
  • Staff 500
  • DMA SL
UK LERAP status None
Formulation and application details Often supplied as a soluble concentrate which is mixed with water and applied as a spray.


ENVIRONMENTAL FATE

for 2,4-D

Property Click here for information on the parameters used to describe environmental fate on this site Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with fate data Interpretation Click here for information on the way in which we interpret environmental fate data
Solubility - In water at 20oC (mg l-1) 24300 A5 High
Solubility - In organic solvents at 20oC (mg l-1) 6400 A5 - Toluene -
212000 A5 - Acetone -
810000 A5 - Methanol -
8000 A5 - Dichloromethane -
Melting point (oC) 138.7 A5 -
Boiling point (oC) 273.0 A5 -
Degradation point (oC) 200 A4 -
Flashpoint (oC) Not expected to self ignite; Not highly flammable] A5 -
Octanol-water partition coefficient at pH 7, 20oC P 1.51 X 10-01 Calculated -
Log P -0.82 A5 Low
Bulk density (g ml-1)/Specific gravity 1.57 B5 -
Dissociation constant (pKa) at 25oC 3.40 A5 -
Note: Strong acid
Vapour pressure at 20oC (mPa) 0.009 A5 Low volatility
Henry's law constant at 25oC (Pa m3 mol-1) 4.0 X 10-06 A4 Non-volatile
GUS leaching potential index Click here for a note on the limitations of the GUS index 1.69 Calculated Low leachability
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate Click here for a note on the limitations of the SCI-GROW index Value 3.88 X 10-03 Calculated -
Note -
Potential for particle bound transport index Click here for a note on the limitations of the potential for particle bound transport index - Calculated Low
Maximum UV-vis absorption L mol-1 cm-1 pH 1.16: 227nm=7344.4, 228nm=1448.9
pH 7.0: 228nm=8815.6, 283nm=1940
pH 11.3: 229nm=8984.5nm, 283nm=1977.5
A5 -
Surface tension (mN m-1) 70.5 A5 -

Degradation:
Property Click here for information on the parameters used to describe substance degradation Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with degradation data Interpretation Click here for information on the way in which we interpret substance degradation data
General biodegradability -
Soil degradation (days) (aerobic) DT50 (typical) 4.4 A5 Non-persistent
DT50 (lab at 20oC) 4.4 A5 Non-persistent
DT50 (field) 28.8 A5 Non-persistent
DT90 (lab at 20oC) 47.9 A5 -
DT90 (field) 96.3 A5 -
DT50 modelling endpoint - - -
Note EU dossier lab studies DT50 range 1.2-94.6 days, DT90 range 5.4-195.56 days; Field studies DT50 range 22-38 days, DT90 range 74-127 days; Other sources: 1.7-13.1 days (R3)
Dissipation rate RL50 on plant matrix Value 2.2 R4 -
Note Published literature RL50 range 1.1-3.0 days, 3 field crops, various matrices, n=3
Dissipation rate RL50 on and in plant matrix Value 12.7 R4 -
Note Published literature RL50 range 1.1-24.8 days, 3 field crops, various matrices, n=5
Aqueous photolysis DT50 (days) at pH 7 Value 38 A5 Stable
Note -
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value Stable A5 -
Note Stable between pH 5 to pH 9
Water-sediment DT50 (days) 18.2 A5 Fast
Water phase only DT50 (days) 7.7 A5 Moderately fast

Soil adsorption and mobility:
Property Click here for information on the parameters used to describe substance adsorption and mobility Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with adsorption and mobility data Interpretation Click here for information on the way in which we interpret substance adsorption and mobility
Linear Kd 0.70 A5 Mobile
Koc 39.3
Notes and range EU dossier Kd range 0.32-1.22 mL/g, Koc range 23-68 mL/g, Soils=7; Other literature multiple studies Kd range 1.59-1.88 mL/g, Koc range 31-275 mL/g (R4)
Freundlich Kf 0.45 A5 Mobile
Kfoc 24
1/n 0.83
Notes and range EU dossier Kf range 0.19-0.83 mL/g, Kfoc range 12-42 mL/g, 1/n range 0.78-0.90, Soils=7; Other literature multiple studies Kf range 0.003-8.7 mL/g, Kfoc range 0.15-875 mL/g, 1/n range 0.35-1.59, Soils = 18
pH sensitivity No

Key metabolites:
Metabolite Formation medium Estimated maximum occurrence fraction 1107/2009 relevancy Click here for further information on 1107/2009 relevancy
2,4-dichlorophenol This metabolite may cause environmental pollution, click here for further information Soil   0.380   Relevant; Major fraction
2,4-dichloro-1-methoxybenzene This metabolite may cause environmental pollution, click here for further information Soil   0.150   Relevant; Major fraction
4-chlorophenol This metabolite may cause environmental pollution, click here for further information Soil   0.330   Relevant; Major fraction

Other known metabolites:
Metabolite name and reference Aliases Formation medium / Rate Estimated maximum occurrence fraction Metabolising enzymes
1,2,4-benzenetriol - Water (photolysis) - -
2-ethylhexyl (2,4-dichlorophenoxy)acetate 2,4-D 2-EHE - - -
(2,5-dichloro-4-hydroxyphenoxy)acetic acid 4-OH-2,5-D Plant - -
(4-chlorophenoxy)acetic acid - - - -
(2,4-dichloro-5-hydroxyphenoxy)acetic acid 5-OH-2,4-D Plant - -
(2,3-dichloro-4-hydroxyphenoxy)acetic acid 4-OH-2,3-D Plant - -


ECOTOXICOLOGY

for 2,4-D

Property Click here for information on the parameters used to describe substance ecotoxicology Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with ecotoxicology data Interpretation Click here for information on the way in which we interpret substance ecotoxicology
Bio-concentration factor BCF (l kg-1) 10 A5 (Whole fish) Low potential
CT50 (days) Not available -
Mammals - Acute oral LD50 (mg kg-1) > 300 A5 Rat Moderate
Mammals - Short term dietary NOEL (mg kg-1) 60 A5 Rat High
(ppm diet) - -
Birds - Acute LD50 (mg kg-1) > 500 A5 Colinus virginianus Moderate
Birds - Short term dietary (LC50/LD50) > 5620 mg kg-1 A4 Colinus virginianus -
Fish - Acute 96 hour LC50 (mg l-1) 100 A4 Pimephales promelas Moderate
Fish - Chronic 21 day NOEC (mg l-1) 27.2 J3 Oryzias latipes, 28 day Low
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) 134.2 A5 Daphnia magna Low
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) 46.2 A5 Daphnia magna Low
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) 2.7 A5 Lemna gibba Moderate
Non-target plants 19 A5 Lettuce
Vegetative vigour, ER50
as g/ha
-
27 A5 Lettuce
Seedling emergence, ER50
as g/ha
-
Algae - Acute 72 hour EC50, growth (mg l-1) 24.2 A5 Raphidocelis subcapitata Low
Algae - Chronic 96 hour NOEC, growth (mg l-1) 100 J4 Chlorella vulgaris Low
Honeybees Contact acute 48 hour LD50 (μg bee-1) > 100 A5 Low
Oral acute 48 hour LD50 (μg bee-1) 94 A5 Moderate
Unknown mode acute 48 hour LD50 (μg bee-1) - - -
Earthworms - Acute 14 day LC50 (mg kg-1) 350 A5 Eisenia foetida Moderate
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) - - -
Other soil macro-organisms - e.g. Collembola LR50 / EC50 / NOEC / % Effect - - -
Other arthropod (1) LR50 g ha-1 3000 >
A5 Typhlodromus pyri
-
% Effect 7.5
-13.2
Mortality
Beneficial capacity
Dose: 3.0 kg ha-1
A5 Aphidius rhopalosiphi
-
Other arthropod (2) LR50 g ha-1 3000 >
A5 Aphidius rhopalosiphi
-
% Effect 5.3
-6.2
Mortality
Beneficial capacity
Dose: 3.0 kg ha-1
A5 Typhlodromus pyri
-
Soil micro-organisms Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect
A5
Dose: 3 mg kg-1, 28 days
-
Mesocosm study data NOEAEC mg l-1 - - -
NOEAEC mg l-1 - - -


HUMAN HEALTH AND PROTECTION

for 2,4-D

General:
Property Click here for information on the parameters used to describe human health and protection issues Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with human health and protection data Interpretation Click here for information on the way in which we interpret human health and protection data
Threshold of Toxicological Concern (Cramer Class) Click here for a note on the limitations of the Cramer class High (class III) - -
Mammals - Acute oral LD50 (mg kg-1) > 300 A5 Rat Moderate
Mammals - Dermal LD50 (mg kg-1 body weight) > 2000 A5 Rat -
Mammals - Inhalation LC50 (mg l-1) > 1.79 A5 Rat, 4hr (whole body) -
Other Mammal toxicity endpoints - -
ADI - Acceptable Daily Intake (mg kg-1bw day-1) 0.05 A5 Rat, SF=100 -
ARfD - Acute Reference Dose (mg kg-1bw day-1) None allocated A5 Rat -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) - - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) 0.15 A4 Rat, SF=100 -
Dermal penetration studies (%) 0.1-4.0 A5 concentration dependent -
Dangerous Substances Directive 76/464 - - -
Exposure Limits [UK LT TWA 8 hr: 10 mg/m3], [UK STEL 15 mins: 20 mg/m3] UK EA QS database, 2018 -
Exposure Routes Public Small risk of dermal exposure from contact with sprayed vegetation
No risk to consumers via acute residue
Occupational Moderate risk of inhalation and dermal exposure depending on personal protection clothing and equipment utilised
European MRLs Click here for the EU MRL pesticide database
Drinking Water Standards Non-statutory WHO drinking water guideline 0.03 mg/L UK EA QS database, 2018 -
Drinking Water MAC (μg l-1) 70.0 F4 (For USA - EPA drinking water regulations) -

Health issues:
Carcinogen Mutagen Endocrine disrupter Reproduction / development effects Cholinesterase inhibitor Neurotoxicant

Respiratory tract irritant Skin irritant Skin sensitiser Eye irritant Phototoxicant

-

-

General human health issues Excessive doses may affect digestive systems
Possible liver and kidney toxicant
Endocrine issues - Synergistic androgenic effects when combined with testosterone

: Yes, known to cause a problem
: No, known not to cause a problem
: Possibly, status not identified
- : No data found

Handling issues:
Property Click here for information on the parameters used to describe substance handling issues Value Source/Quality Score/Other Information Click here for information on the primary data sources used to populate this database with data on handling issues Interpretation Click here for information on the way in which we interpret data on handling issues
General Click here for a description of the International Maritime Dangerous Goods (IMDG) codes Corrosive to metals
IMDG Transport Code is usually 9 or 6.1
Not explosive or oxidising
CLP classification 2013 Health: H302, H317, H318, H335
Environment: H412
EC Risk Classification Click here to view information omn the EU risk phrases Xn - Harmful: R22, R41, R43
Xi - Irritant: R37
N - Dangerous for the environment: R52, R53
EC Safety Classification Click here to view information omn the EU safety phrases S2, S24/25, S26, S46, S61, S36/37/39
WHO Classification II - Moderately hazardous
US EPA Classification (formulation) II - III - -
UN Number Usually 3082 or 3077
Waste disposal & packaging Click here for a description of UN packaging marks Dispose of in accordance with local regulations
Packaging Group III (minor danger)


TRANSLATIONS

for 2,4-D

Language Name
English 2,4-D
French 2,4-D
German 2,4-D
Danish 2,4-D
Italian 2,4-D
Spanish 2,4-D
Greek -
Slovenian 2,4-D
Polish 2,4-D
Swedish 2,4-D
Hungarian 2,4-D
Dutch 2,4-D

Record last updated: Thursday 23 August 2018
Contact: aeru@herts.ac.uk
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