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2,4-DB (Ref: ENT 8538)
** hedonal ** trinoxol ** Translations

Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home

SUMMARY

2,4-DB is a post-emergence herbicide that has approval for use in the EU. It is highly soluble in water and most organic solvents. It is relatively volatile but it may leach to groundwater under certain conditions. It is not persistent in soil systems but may tend to be persistent in aquatic systems. It is moderately toxic to mammals and there is some concern regarding its potential for bioaccumulation. It is moderately toxic to birds, earthworms, honeybees and most aquatic organisms.

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

Description: A herbicide used for post-emergence control of many annual and perennial broad-leaved weeds

Example pests controlled: Broad-leaved weeds including bindweed, thistles, docks, nettles, mallow, pigweed, plantain; Brush

Example applications: Wheat; Barley; Maize; Sorghum; Rice; Grassland: Lawns and turf areas; Aquatic situations; Non-cropped areas including roadsides, railways and utilities rights of way.

Efficacy & activity: -

Availability status: Current

Introduction & key dates: 1942, first identified; 1944 first marketed

EC Regulation 1107/2009 (repealing 91/414):
Status Approved
Dossier rapporteur/co-rapporteur Belgium/Greece
Date inclusion expires 31/10/2032
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 C10H10Cl2O3
Canonical SMILES CNC.C1=CC(=C(C=C1Cl)Cl)OCCCC(=O)O
Isomeric SMILES No data
International Chemical Identifier key (InChIKey) YIVXMZJTEQBPQO-UHFFFAOYSA-N
International Chemical Identifier (InChI) InChI=1S/C10H10Cl2O3/c11-7-3-4-9(8(12)6-7)15-5-1-2-10(13)14/h3-4,6H,1-2,5H2,(H,13,14)
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
Substance group Aryloxyalkanoic acid
Minimum active substance purity 940 g/kg
Known relevant impurities EU dossier 2016 - dibenzo-p-dioxins; polychlorinated dibenzofurans
Substance origin Synthetic
Mode of action Selective, systemic. Synthetic auxin causing stem and leaf malformations leading to death.
CAS RN 94-82-6
EC number 202-366-9
CIPAC number 83
US EPA chemical code 030801
PubChem CID 1489
Molecular mass (g mol-1) 249.09
PIN (Preferred Identification Name) 4-(2,4-dichlorophenoxy)butanoic acid
IUPAC name 4-(2,4-dichlorophenoxy)butyric acid
CAS name 4-(2,4-dichlorophenoxy)butanoic acid
Other status information -
Relevant Environmental Water Quality Standards -
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 -
Physical state White crystals whith faint phenolic odour
Related substances & organisms

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
  • United Phosphorus
  • Headland
Example products using this active
  • Butoxone
  • Butyrac
  • Cedar
  • DB Straight
  • Embutone
  • Venceweed
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-DB

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) 4385 A5 High
Solubility - In organic solvents at 20oC (mg l-1) 185200 A5 - Acetone -
113800 A5 - Methanol -
90700 A5 - Ethyl acetate -
10500 A5 - Xylene -
Melting point (oC) 119 A5 -
Boiling point (oC) Decomposes before boiling A5 -
Degradation point (oC) 270 A5 -
Flashpoint (oC) Not expected to self ignite; Not highly flammable A5 -
Octanol-water partition coefficient at pH 7, 20oC P 1.66 X 1001 Calculated -
Log P 1.22 A5 Low
Bulk density (g ml-1)/Specific gravity 1.46 A5 -
Dissociation constant (pKa) at 25oC 4.1 A5 -
Note: Weak acid
Vapour pressure at 20oC (mPa) 9.0 X 10-04 A5 Low volatility
Henry's law constant at 25oC (Pa m3 mol-1) 4.6 X 10-06 A5 Non-volatile
GUS leaching potential index Click here for a note on the limitations of the GUS index 0.64 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 1.59 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 Neutral sol: 230 nm= 9820, 284nm = 2260, 291nm = 1790 A5 -
Surface tension (mN m-1) 71.0 A5 99.1% w/ww -

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) 2.87 A5 Non-persistent
DT50 (lab at 20oC) 2.87 A5 Non-persistent
DT50 (field) 15.6 A5 Non-persistent
DT90 (lab at 20oC) 5.7 A5 -
DT90 (field) - - -
DT50 modelling endpoint - - -
Note 2016 EU Dossier lab studies DT50 range 1.2-25.1 days, DT90 range 6.2-75 days, Soils=5; 2002 EU dossier lab studies DT50 range 1-2 days, DT90 range 4-7.3 days; field studies DT50 7.2-24 days (warm conditions)
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 17.2 A5 Slow
Note Variable with pH: 6.3 days at pH 5, 6.9 days at pH 9
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value Stable A5 -
Note Stable between pH 5 and pH 9
Water-sediment DT50 (days) 17 A5 Fast
Water phase only DT50 (days) 12.5 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 - A5 Moderately mobile
Koc 224
Notes and range Other sources: 440 mL/g (DW4)
Freundlich Kf 6.03 A5 Moderately mobile
Kfoc 392.9
1/n 0.80
Notes and range EU 2016 dossier Kf range 0.46-18.3 mL/g, Kfoc range 37.8-1306 mL/g, 1/n range 0.65-0.95, Soils=7
pH sensitivity Adsorption decreases with increasing pH

Key metabolites:
Metabolite Formation medium Estimated maximum occurrence fraction 1107/2009 relevancy Click here for further information on 1107/2009 relevancy
2,4-D (Ref: L 208) This metabolite may cause environmental pollution, click here for further information Soil   0.261   Major fraction, Relevancy unknown
2,4-dichlorophenol This metabolite may cause environmental pollution, click here for further information Soil   0.112   Major fraction, Relevancy unknown

Other known metabolites:
Metabolite name and reference Aliases Formation medium / Rate Estimated maximum occurrence fraction Metabolising enzymes
2,3,7,8-tetrachlorodibenzo[b,e]{1,4]dioxine TCDD - - -
N-[4-(2,4-dichlorophenoxy)butanoyl]glycine 2,4-DB glycine - - -
4-(2,5-dichloro-4-hydroxyphenoxy)butanoic acid 2,5-Cl-4-HPBA - - -
(2,4-dichloro-6-hydroxyphenoxy)acteic acid 2,4-Cl-6-HPAA - - -
methyl 4-(2,4-dichlorophenoxy)butanoate 2,4-DB-methyl ester - - -
(4-chlorophenoxy)acetic acid
(Ref: )
Note: Major fraction, Relevancy unknown
4-CPA - - -


ECOTOXICOLOGY

for 2,4-DB

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) 175 Q3 May bioaccumulate but low risk due to usage Threshold for concern
CT50 (days) Not available -
Mammals - Acute oral LD50 (mg kg-1) 1470 A5 Rat Moderate
Mammals - Short term dietary NOEL (mg kg-1) 43 A4 Rat, 28 day High
(ppm diet) 300 -
Birds - Acute LD50 (mg kg-1) 1545 A5 Colinus virginianus Moderate
Birds - Short term dietary (LC50/LD50) > 5000 mg kg-1 A5 Colinus virginianus -
Fish - Acute 96 hour LC50 (mg l-1) 3.5 A5 Oncorhynchus mykiss Moderate
Fish - Chronic 21 day NOEC (mg l-1) 63.4 A5 Pimephales promelas, 32 day Low
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) 25 A5 Daphnia magna Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) 3 A5 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) - - -
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg-1) - - -
Aquatic plants - Acute 7 day EC50, biomass (mg l-1) 68.8 A4 Lemna minor, 7 day Low
Non-target plants - - -
- - -
Algae - Acute 72 hour EC50, growth (mg l-1) > 1.1 A4 Raphidocelis subcapitata, 120 hour Moderate
Algae - Chronic 96 hour NOEC, growth (mg l-1) 67.9 A4 Unknown species Low
Honeybees Contact acute 48 hour LD50 (μg bee-1) - - -
Oral acute 48 hour LD50 (μg bee-1) > 100 A5 Low
Unknown mode acute 48 hour LD50 (μg bee-1) - - -
Earthworms - Acute 14 day LC50 (mg kg-1) > 1000 A5 Eisenia foetida Low
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 - - -
% Effect 3.0 Mortality
Dose: 1.8 kg ha-1
A5 Aphidius rhopalosiphi
-
Other arthropod (2) LR50 g ha-1 - - -
% Effect 13 Reduction in eggs
Dose: 1.8 Kg ha-1
A5 Typhlodromus pyri
-
Soil micro-organisms Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect
A5
Dose: 1.8 kg ha-1
-
Mesocosm study data NOEAEC mg l-1 - - -
NOEAEC mg l-1 - - -


HUMAN HEALTH AND PROTECTION

for 2,4-DB

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) 1470 A5 Rat Moderate
Mammals - Dermal LD50 (mg kg-1 body weight) > 2000 A5 Rat -
Mammals - Inhalation LC50 (mg l-1) > 2.3 A5 Rat, 4 hr (whole body) -
Other Mammal toxicity endpoints - -
ADI - Acceptable Daily Intake (mg kg-1bw day-1) 0.02 A5 -
ARfD - Acute Reference Dose (mg kg-1bw day-1) None allocated A5 -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) - - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) 0.08 A4 Dog, 1 year, SF=100 -
Dermal penetration studies (%) 1.1 A5 -
Dangerous Substances Directive 76/464 - - -
Exposure Limits - - -
Exposure Routes Public Unlikely via food or water,
Source: US EPA/EU
No risk to consumers via acute residue
Occupational Possible dermal or inhalation exposure during mixing/loading,
Source: US EPA
European MRLs Click here for the EU MRL pesticide database
Drinking Water Standards Non-statutory WHO drinking water guideline 0.09 mg/L UK EA QS database, 2018 -
Drinking Water MAC (μg l-1) - - -

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 Possible kidney toxicant

: 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 IMDG Transport Code is usually 9
Not explosive or oxidising
CLP classification 2013 Health: H302
Environment: H411
EC Risk Classification Click here to view information omn the EU risk phrases Xn - Harmful: R22
N - Dangerous for the environment: R51, R53
EC Safety Classification Click here to view information omn the EU safety phrases S2, S25, S46, S61, S29
WHO Classification III - Slightly hazardous
US EPA Classification (formulation) III - Caution - Slightly toxic
UN Number Usually 3077
Waste disposal & packaging Click here for a description of UN packaging marks Packaging Group III (minor danger)


TRANSLATIONS

for 2,4-DB

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

Record last updated: Tuesday 30 October 2018
Contact: aeru@herts.ac.uk