Metobromuron (Ref: C 3216)

Metobromuron (Ref: C 3216)	Last updated: 13/06/2024
(Also known as: monobromuron; metbromuron; metobromurone)

SUMMARY

Metobromuron is a pre-emergence herbicide. It is moderately soluble in water, is quite volatile and there is a moderate risk that it may leach to groundwater. It is moderately persistent in soil systems and may also be persistent in water bodies, depending upon conditions. It has a low mammalian toxicity but has a high potential to bioaccumulate. It is classified as an irritant. It is moderately toxic to birds and most aquatic organisms and earthworms but it is not considered toxic to honeybees.

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: GUS: Transition state; Drainflow: Moderately mobile	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Birds chronic ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate	Human health High alert: Carcinogen

GENERAL INFORMATION

Description

A herbicide used pre-emergence and applied to soil surface for the control weeds and grasses

Example pests controlled

Broad-leaved weeds including chickweed, black bindweed, charlock, fat hen, knotgrass, field pansy; Grasses including annual meadow grass, coskspur grass, foxtails

Example applications

Sunflowers; Potatoes; Tomatoes; Soybeans; Tobacco

Efficacy & activity

Availability status

Current

Introduction & key dates

circa 1965, introduced

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/12/2024

UK LERAP status

None

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

France

Date EC 1107/2009 inclusion expires

31/12/2024

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
✓	✓	✓	✓	✓	✓	✓	✓	✓

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

Morocco

Chemical structure

Isomerism

None

Chemical formula

C₉H₁₁BrN₂O₂

Canonical SMILES

CN(C(=O)NC1=CC=C(C=C1)Br)OC

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

WLFDQEVORAMCIM-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C9H11BrN2O2/c1-12(14-2)9(13)11-8-5-3-7(10)4-6-8/h3-6H,1-2H3,(H,11,13)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
metobromuron	-

General status

Pesticide type

Herbicide

Substance groups

Urea herbicide; Phenylurea herbicide; Organobromide compound

Minimum active substance purity

978 g kg⁻¹

Known relevant impurities

EU dossier - none declared

Substance origin

Synthetic

Mode of action

Photosynthetic electron transport inhibitor at the photosystem II.

CAS RN

3060-89-7

EC number

221-301-5

CIPAC number

168

US EPA chemical code

035901

PubChem CID

18290

CLP index number

No data found

Molecular mass

259.10

PIN (Preferred Identification Name)

IUPAC name

3-(4-bromophenyl)-1-methoxy-1-methylurea

CAS name

N'-(4-bromophenyl)-N-methoxy-N-methylurea

Other status information

Possible groundwater pollutant; PAN listed Highly Hazardous Chemical

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Herbicide Resistance Class (WSSA MoA class)

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

Colourless to pale yellow crystals with a musty odour

Formulations

Property

Value

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

Belchim
Ciba-Geigy
BASF
Makhteshim Agan

Example products using this active

Metobromuron 500 SC
Patoran
Pattonex
Praxim

Formulation and application details

Usually supplied as a wettable powder or suspension concentrate

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

328

Moderate

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

500000

Acetone

10000

Hexane

250000

Methanol

250000

Ethyl acetate

Melting point (°C)

95.6

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

173.2

Flashpoint (°C)

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

3.02 X 10⁰²

Calculated

Log P

2.48

Low

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data

Density (g ml⁻¹)

1.52

Dissociation constant pKa) at 25 °C

12.0

Vapour pressure at 20 °C (mPa)

0.144

Low volatility. If applied directly to plants, drift is a concern & mitigation is advisable

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

1.1 X 10^-04

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Surface tension (mN m⁻¹)

72.2

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

34.3

Moderately persistent

DT₅₀ (lab at 20 °C)

34.3

Moderately persistent

DT₅₀ (field)

22.4

Non-persistent

DT₉₀ (lab at 20 °C)

112

Persistent

DT₉₀ (field)

141

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ range 24.6-49.7 days, DT₉₀ range 81.3-165.1 days; Field studies DT₅₀ range 5.4-64.5 days; Other sources: DT₅₀ 24-43 days (R3)

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

Note

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Stable

Note

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

Value

170

Persistent

Note

Water-sediment DT₅₀ (days)

33.8

Moderately fast

Water phase only DT₅₀ (days)

16.2

Slow

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

Moderately mobile

K_oc (mL g⁻¹)

197

Notes and range

Freundlich

K_f (mL g⁻¹)

3.87

Moderately mobile

K_foc (mL g⁻¹)

160

¹/_n

0.89

Notes and range

EU dossier K_f range 2.30-7.82 mL g⁻¹, K_foc range 122-199 mL g⁻¹, ¹/_n range 0.84-0.93, soils=5

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.42

Calculated

Transition state

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

Value

1.14 X 10^-01

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk

18.24

Calculated using the Atkinson method. Assumed 1.5E+06 OH/cm³, 12 hr

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

No data

Known soil metabolites

Metabolite

Major/Minor fraction

$Click here for further information on Major/Minor fraction$

Estimated maximum occurrence fraction

Notes

desmethoxy-metobromuron (Ref: CGA 18236)

Major fraction

0.051

Known groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

4-bromophenylurea (Ref: CGA 18237)

metobromuron metabolite R3

Plant

1-methoxy-1-methyl-3-phenylurea (Ref: HHAC-022)

metobromuron metabolite R6

3-(4-hydroxyphenul)-1-methoxy-1-methylurea (Ref: HHAC-063)

metobromuron metabolite R10

1-(4-hydroxyphenyl)-3-methylurea (Ref: HHAC-065)

metobromuron metabolite R11

1-methyl-3-phenylurea

metobromuron metabolite R9

3-hydroxy-4-bromoaniline (Ref: CGA 14118)

4-hydroxy-5-bromoaniline (Ref: CGA 14120)

3-(4-hydroxyphenyl)-1-hydroxy-1-methylurea (Ref: CGA 14652)

4-bromoaniline

metobromuron metabolite R4

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 10000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat 2 yr

(ppm diet)

250

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

> 16.03

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

1429

Coturnix japonica

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

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

21.6

Colinus virginianus NOEL

Moderate

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

233

Eisenia foetida corr

Moderate

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

Soil micro-organisms

Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect

Dose: 65.9 mg kg⁻¹ soil 84 Day

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

23.66

Folsomia candida corr

Non-target plants

0.77

Lycopersicon esculentum
Vegetative vigour, mortality, EC₅₀
as L product ha⁻¹

> 7.5

Allium cepa
Seedling emergence, EC₅₀
as L product ha⁻¹

Honeybees (Apis spp.)

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

> 200

Apis mellifera

Low

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

119.1

Apis mellifera

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) as Mortality LR₅₀ g ha⁻¹

> 4098

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹

51.2

Typhlodromus pyri

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

43.0

Oncorhynchus mykiss

Moderate

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

0.25

Pimephales promelas

Moderate

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

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

44.1

Daphnia magna

Moderate

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

>= 10

Daphnia magna

Moderate

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (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)

0.31

Lemna gibba

Moderate

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

0.63

Scenedesmus subspicatus

Moderate

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

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)

> 10000

Rat

Low

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

3000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 1.6

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

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

0.008

Mouse SF=100

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

0.3

Rat SF=300

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

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

0.016

Dog SF=100

Dermal penetration studies (%)

0.5-6.3

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Very low risk for proposed uses

Occupational

Low risk for proposed uses

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

GB MRL expected to deviate from the EU MRL in mid-2023

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

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

Possible blood, spleen and bone marrow toxicant
Possible allergen

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H302, H332, H317, H373
Environment: H410

WHO Classification

III (Slightly hazardous)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

metobromuron

French

metobromuron

German

Metobromuron

Danish

metobromuron

Italian

bromuro di metile

Spanish

bromuro de metilo

Greek

Polish

metobromuron

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	13/06/2024
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