Bromoxynil (Ref: ENT 20852)

Bromoxynil (Ref: ENT 20852)	Last updated: 12/01/2021
(Also known as: butil chlorofos; bromotril; bromoxynil phenol)

SUMMARY

A widely used herbicide approved for use in the EU. It has a high aqueous solubility and is not considered to be volatile. The potential for leaching to groundwater is considered low, and it is not expected to be persistent in soil or water systems. It is highly toxic to mammals, is an endocrine distrupter and may cause negative reproduction or development effects. It is moderately toxic to most aquatic and terrestrial biodviersity. The main exceptions are a low toxicity to algae and honeybees by the contact route (not the oral route).

GENERAL INFORMATION

Description

An HBN herbicide used for post-emergence control of annual broad-leaved weeds. it is also a pesticide transformation product

Example pests controlled

Pigweed; Mayweed; Knotweed; Shepherd's purse; Goosefoot; Morning glory; Dwarf marigold; Stinkweed; Cocklebur; Wild radish

Example applications

Cereals including wheat, barley, oats; Lucerne; Corn; Sorghum; Onions; Flax; Mint; Turf; Non-crop land

Efficacy & activity

Proved as effective by extensive use over a prolonged period and via field experiments

Availability status

Current

Introduction & key dates

1963, first reported.

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

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

Australia

Chemical structure

Isomerism

None

Chemical formula

C₇H₃Br₂NO

Canonical SMILES

C1=C(C=C(C(=C1Br)O)Br)C#N

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

UPMXNNIRAGDFEH-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C7H3Br2NO/c8-5-1-4(3-10)2-6(9)7(5)11/h1-2,11H

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
bromoxynil	-

General status

Pesticide type

Herbicide, Metabolite

Metabolite Type

Soil

Substance group

Hydroxybenzonitrile

Minimum active substance purity

970 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

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

CAS RN

1689-84-5

EC number

216-882-7

CIPAC number

US EPA chemical code

035301

PubChem CID

15531

Molecular mass

276.9

PIN (Preferred Identification Name)

3,5-dibromo-4-hydroxybenzonitrile

IUPAC name

3,5-dibromo-4-hydroxybenzonitrile

CAS name

3,5-dibromo-4-hydroxybenzonitrile

Other status information

Marine Pollutant; PAN listed Highly Hazardous Chemical

Relevant Environmental Water Quality Standards

UK Environment Agency non-statutory standard for the protection of aquatic life: freshwater and saltwater annual average 100 µg l⁻¹; max acceptable conc: 1000 µg l⁻¹

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

Clear to white crystalline solid

Related substances & organisms

diflufenican

ioxynil

ethofumesate

mecoprop-P

prosulfuron

terbuthylazine

Can be a metabolite of:

Parent

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

bromoxynil octanoate

Soil

0.446

Major fraction, Relevant

bromoxynil heptanoate

Soil

0.317

Major fraction, Relevant

bromoxynil butanoate

Soil

0.379

Major fraction, Relevant

Formulations

Property

Value

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

Emblem
Brominex
Chipco Buctril
Brominal Plus

Example products using this active

Barclay
Nufarm
Dow AgroSciences

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)

38000

High

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

186000

Acetone

80500

Methanol

46700

n-Octanol

51100

Acetonitrile

Melting point (°C)

190.5

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

270

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

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

1.86 X 10⁰⁰

Calculated

Log P

0.27

Low

Bulk density (g ml⁻¹)

1.63

Dissociation constant pKa) at 25 °C

3.86

Weak acid

Vapour pressure at 20 °C (mPa)

0.12

Low volatility

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

8.7 X 10^-07

Non-volatile

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

In methanol: 221.2nm = 30343, 286.8nm = 18302, 295.0nm=16215

Surface tension (mN m⁻¹)

73.0

at 20 °C 90%

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

1.04

Non-persistent

DT₅₀ (lab at 20 °C)

1.04

Non-persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

5.16

Non-persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU 2017 dossier lab studies DT₅₀ range 0.15-4.42 days, DT₉₀ range 0.60-24.17 days, Soils=17; Other sources: field studies from literature (R3), generally DT₅₀ 7-10 days (Q3)

Dissipation rate RL₅₀ on plant matrix

Value

Note

Dissipation rate RL₅₀ on and in plant matrix

Value

2.2

Note

Published literature RL₅₀ range 1.1-3.2 days, 2 field crops, various matrices, n=2

Aqueous photolysis DT₅₀ (days) at pH 7

Value

0.5

Fast

Note

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

Value

Stable

Note

Water-sediment DT₅₀ (days)

Fast

Water phase only DT₅₀ (days)

Moderately fast

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

Moderately mobile

K_oc

302

Notes and range

Freundlich

K_f

2.84

Moderately mobile

K_foc

127.2

¹/_n

0.98

Notes and range

EU 2017 dossier kf range 0.8-5.9 mL g⁻¹; K_foc range 57-256 mL g⁻¹; ¹/_n range 0.937-1.009, Soils=5

pH sensitivity

Yes - lower mobility at low pH

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.71

Calculated

Low leachability

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

Value

1.80 X 10^-02

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

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

Soil

0.348

Major fraction, Relevant

3,5-di-bromo-4-hydroxybenzamide

Soil

0.216

Major fraction, Relevant

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

130

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

16.6

Rat 2 year

High

(ppm diet)

100

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

> 17.75

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

217

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

1380 mg kg feed⁻¹

Anas platyrhynchos

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

15.9

Anas platyrhynchos NOAEL

Moderate

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

29.2

Lepomis macrochirus

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

2.0

Oncorhynchus mykiss

Moderate

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

12.5

Daphnia magna

Moderate

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

3.1

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)

0.033

Lemna gibba

Moderate

Non-target plants

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

0.12

Navicula pelliculosa 72 hour

Moderate

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

3.13

Green algae population study

Low

Honeybees (Apis spp.)

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

150

Apis mellifera

Low

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

10.9

Apis mellifera

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)

> 100

Bombus terrestris

Low

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)

Eisenia foetida

Moderate

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

4.5

Eisenia foetida

Moderate

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Folsomia candida

Other arthropod (1)

LR₅₀ g ha⁻¹

% Effect

17.9 / -23.6

Mortality / Parasitism [Dose: 0.45 kg ha⁻¹]
Aphidius rhopalosiphi adults

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

Mortality [Dose: 0.45 kg ha⁻¹]
Typhlodromus pyri

Soil micro-organisms

Nitrogen mineralisation: Low, transient effect
Carbon mineralisation: Low, transient effect

Dose: 3.73 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)

130

Rat

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.15

Rat

Other Mammal toxicity endpoints

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

0.03

Dog SF=100

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

0.013

Rat SF=300

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

0.013

Rat SF=300

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

0.003

Dog SF=100

Dermal penetration studies (%)

3.5

Dangerous Substances Directive 76/464

Exposure Routes

Public

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

Occupational

Low risk from registered uses with PPE/PPC, High risk without PPE/PPC

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

General human health issues

USEPA - possible human carcinogen
Possible liver and thyroid 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, H330, H360d
Environment: H400, H410

EC Risk Classification

Reproduction risk category 3: R63
T+ - Very toxic: R26
T - Toxic: R25
Xn - Harmful: R43
N - Dangerous for the environment: R50, R53

EC Safety Classification

S1/2, S27/28, S36/37, S45, S60, S61, S63

WHO Classification

II (Moderately hazardous)

UN Number

2588

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

Language

Name

English

bromoxynil

French

bromoxynil

German

Bromoxynil

Danish

bromoxynil

Italian

bromoxinil

Spanish

bromoxinil

Greek

bromoxynil

Polish

bromoksynil

Swedish

Hungarian

bromoxynil

Dutch

bromoxynil

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