Bromoxynil butanoate

Bromoxynil butanoate	Last updated: 12/01/2021
(Also known as: bromoxynil butyrate)

SUMMARY

A widely used herbicide approved for use in the EU. It has a low aqueous solubility and a low volatility. There is a low potential for leaching to groundwater based on its chemical properties. It is not expected to be persistent in soil or water systems. It is moderately toxic via the oral route to mammals, is an endocrine distrupting chemical and a skin sensitiser. It is highly toxic to fish but less so to other aquatic and terresitial biodiversity.

GENERAL INFORMATION

Description

An HBN herbicide used for post-emergence control of annual broad-leaved weeds

Example pests controlled

Ragweed; Smartweed; Nightshade; Kochia; Wild mustard

Example applications

Alfalfa; Garlic; Corn; Sorghum; Cereals including wheat, barley; Turf; Non-cropped areas including rights-of-way, pathways

Efficacy & activity

Efficiacy proven from prolonged use in the EU and from experimental studies

Availability status

Current

Introduction & key dates

circa 1980

UK regulatory status

UK COPR regulatory status

Phasing out

Date COPR inclusion expires

Expired

UK LERAP status

Buffer probably required in UK - see product label

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

France/Germany

Date EC 1107/2009 inclusion expires

31/07/2021

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

Australia, Latin America, USA

Chemical structure

Isomerism

None

Chemical formula

C₁₁H₉Br₂NO₂

Canonical SMILES

CCCC(=O)OC1=C(C=C(C=C1Br)C#N)Br

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

PGMZYNZXIYOOHJ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C11H9Br2NO2/c1-2-3-10(15)16-11-8(12)4-7(6-14)5-9(11)13/h4-5H,2-3H2,1H3

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
bromoxynil	Parent

General status

Pesticide type

Herbicide

Substance group

Hydroxybenzonitrile

Minimum active substance purity

967 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Select contact action with some systemic activity. Inhibits photosynthesis (photosystem II).

CAS RN

3861-41-4

EC number

223-374-9

CIPAC number

87.403

US EPA chemical code

PubChem CID

62526

Molecular mass

347.0

PIN (Preferred Identification Name)

2,6-dibromo-4-cyanophenyl butanoate

IUPAC name

2,6-dibromo-4-cyanophenyl butyrate

CAS name

2,6-dibromo-4-cyanophenyl butanoate

Other status information

Marine Pollutant; PAN listed Highly Hazardous Chemical

Relevant Environmental Water Quality Standards

Herbicide Resistance Classification (HRAC)

Herbicide Resistance Classification (WSSA)

Insecticide Resistance Classification (IRAC)

Not applicable

Fungicide Resistance Classification (FRAC)

Not applicable

Examples of recorded resistance

Physical state

Light beige coloured powdery solid

Formulations

Property

Value

Example manufacturers & suppliers of products using this active now or historically

Example products using this active

Formulation and application details

Spray application

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

5.4

Low

Solubility - In organic solvents at 20 °C (mg l⁻¹)

70000

Ethanol

23000

n-Hexane

600000

Toluene

600000

Acetone

Melting point (°C)

Boiling point (°C)

353

Degradation point (°C)

320

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

Octanol-water partition coefficient at pH 7, 20 °C

7.24 X 10⁰³

Calculated

Log P

3.86

High

Bulk density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

0.28

Low volatility

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

1.80 X 10^-02

Non-volatile

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

In methanol: 213nm= 48122, 283nm=723, 294nm=633

Surface tension (mN m⁻¹)

68.60

at 20 °C 97.6%

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

0.58

Non-persistent

DT₅₀ (lab at 20 °C)

0.58

Non-persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

1.99

Non-persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU 2017 dossier lab studies DT₅₀ range 0.5-0.67 days, DT₉₀ range 1.69-2.29 days, Soils =2

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

0.12

Fast

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

Moderately persistent

Note

DT₅₀: pH 4: 44 days; pH 9: 1.1 days

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

K_oc

Notes and range

Freundlich

K_f

K_foc

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate

Value

Cannot be calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

bromoxynil (Ref: ENT 20852)

Soil

0.379

Major fraction, Relevant

3,5-di-bromo-4-hydroxybenzamide

Soil

0.150

Major fraction, Relevant

3,5-di-bromo-4-hydroxybenzoic acid

Soil

0.057

Major fraction, Relevant

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

116

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)

420

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

0.032

Oncorhynchus mykiss

High

Fish - Chronic 21 day NOEC (mg l⁻¹)

0.008

Pimephales promelas

High

Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

0.208

Daphnia magna

Moderate

Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

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)

0.15

Lemna gibba

Moderate

Non-target plants

Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)

0.75

Navicula pelliculosa 96 hr

Moderate

Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

199

Apis mellifera unknown test duration

Low

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

76.4

Apis mellifera unknown test duration

Moderate

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

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)

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

2.3

Eisenia foetida EC10 corr

Moderate

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

125

Folsomia candida

Other arthropod (1)

LR₅₀ g ha⁻¹

% Effect

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

Soil micro-organisms

Nitrogen mineralisation: Low, transient effect

Dose: 2.57 mg kg⁻¹ 28 days

Mesocosm study data

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)

116

Rat

Moderate

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

1.217

Rat

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

0.01

Mouse 18 mnths SF=100

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

0.04

SF=100

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

0.01

Dog SF=100

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Minimal risk from dietary exposure
Risk assessment indicates ARfD would not normally be execeeded

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

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

Possible liver toxicant

Handling issues

Property

Value and interpretation

General

IMDG Transport Code is usually 6.1
Not explosive or oxidising

CLP classification 2013

Health: H301, H317, H319, H332, H360d
Environment: H400, H410

EC Risk Classification

Reproduction risk category 3: R63
Xn - Harmful: R20/22, R43
N - Dangerous for the environment: R50, R53

EC Safety Classification

S2, S36/37, S46, S60, S61

WHO Classification

II (Moderately hazardous)

UN Number

Usually 2558

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

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Name

English

bromoxynil butanoate

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Record last updated:	12/01/2021
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