Defenuron (Ref: IPO 4328)-Pesticide database

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Defenuron (Ref: IPO 4328)

(Also known as: NSC 10989)

Defenuron is an obsolete herbicide. It is highly soluble in water and is non-volatile. It has a low toxicity to fish. It is not highly toxic to mammals if ingested.

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
	Ecotoxicity Low alert: Fish acute ecotoxicity: Low Warning: Significant data are missing	Human health Low alert Warning: Significant data are missing

GENERAL INFORMATION

An obsolete herbicide that was used to control weeds in a range of crops

Example pests controlled

Example applications

Potatoes; Cereals; Maize; Vines; Fruits; Sunflowers; Peas; Vines; Forestry

Efficacy & activity

Availability status

Considered obsolete but may be available in some countries

Introduction & key dates

UK regulatory status

UK COPR regulatory status

Date COPR inclusion expires

UK LERAP status

No UK approval for use

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Dossier rapporteur/co-rapporteur

Date EC 1107/2009 inclusion expires

EU Candidate for substitution (CfS)

Listed in EU database

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

Chemical structure

Chemical formula

C₈H₁₀N₂O

Canonical SMILES

CNC(=O)NC1=CC=CC=C1

Isomeric SMILES

International Chemical Identifier key (InChIKey)

SQBHGDSDVWCPHN-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C8H10N2O/c1-9-8(11)10-7-5-3-2-4-6-7/h2-6H,1H3,(H2,9,10,11)

2D structure diagram/image available?

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
defenuron	-

Substance groups

Urea herbicide; Phenylurea herbicide

Minimum active substance purity

Known relevant impurities

Substance origin

Photosyntheis inhibition, active via leaves and roots

US EPA chemical code

CLP index number

PIN (Preferred Identification Name)

1-methyl-3-phenylurea

1-methyl-3-phenylurea

N-phenyl-N-methylurea

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Classification (HRAC)

Herbicide Resistance Classification (WSSA)

Insecticide Resistance Classification (IRAC)

Fungicide Resistance Classification (FRAC)

Examples of recorded resistance

Colourless crystalline solid

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

Example products using this active

Obsolete - not thought to be commercially available for crop protection applications

Formulation and application details

Was usually supplied as a wettable powder

ENVIRONMENTAL FATE

Source; quality score; and other information

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

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

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

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

Methylene chloride

Melting point (°C)

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

Boiling point (°C)

Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source

Degradation point (°C)

Flashpoint (°C)

Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source

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

V2 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
2 = Unverified data of unknown source

Fat solubility of residues

Density (g ml⁻¹)

Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

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

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

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

Surface tension (mN m⁻¹)

Source; quality score; and other information

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Dissipation rate RL₅₀ on plant matrix

Dissipation rate RL₅₀ on and in plant matrix

Aqueous photolysis DT₅₀ (days) at pH 7

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

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Soil adsorption and mobility

Source; quality score; and other information

Notes and range

Notes and range

Source; quality score; and other information

GUS leaching potential index

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

Cannot be calculated

Potential for particle bound transport index

Potential for loss via drain flow

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Known metabolites

None

Terrestrial ecotoxicology

Source; quality score; and other information

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

Mammals - Short term dietary NOEL

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

Birds - Acute LD₅₀ (mg kg⁻¹)

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

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

Soil micro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Honeybees (Apis 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)

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 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)

Beneficial insects (Predatory mites)

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Source; quality score; and other information

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

Poecilia reticulata

Fish - Chronic 21 day NOEC (mg l⁻¹)

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

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)

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

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

Mesocosm study data

NOEAEC mg l⁻¹

NOEAEC mg l⁻¹

HUMAN HEALTH AND PROTECTION

Source; quality score; and other information

Threshold of Toxicological Concern (Cramer Class)

High (class III)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source

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

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

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

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

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

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

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

EU MRL pesticide database

GB MRL Register

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Mammalian dose elimination route and rate

Specific human health issues

Endocrine disruptor

A0 A = Chromosome aberration (EFSA database)
0 = No data

B0 B = DNA damage/repair (EFSA database)
0 = No data

C0 C = Gene mutation (EFSA database)
0 = No data

D0 D = Genome mutation (EFSA database)
0 = No data

E2 E = Unspecified genotoxicity type (miscellaneous data source)
2 = Mixed/ambiguous results

Reproduction / development effects

Acetyl cholinesterase inhibitor

XNo, known not to cause a problem

Respiratory tract irritant

Skin sensitiser

General human health issues

No further information available

Handling issues

Value and interpretation

No information available

CLP classification 2013

WHO Classification

Not classified: Obsolete

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

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