Diuron (Ref: DPX 14740)

Diuron (Ref: DPX 14740)	Last updated: 15/03/2024
(Also known as: dichlorfenidim)

SUMMARY

Diuron is a pre-emergence herbicide. It has a low aqueous solubility, a low volatility and may, under certain conditions, leach to groundwater. It may be moderately persistent in soil systems and may also persist in water. It is moderately toxic to mammals and is classified as an irritant. It is moderately toxic to birds, earthworms, most aquatic species but is slightly more toxic to algae. It has a low toxicity 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 High alert: Persistent	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Bees acute oral ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health High alert: Endocrine disrupter

GENERAL INFORMATION

Description

A pre-emergence residual herbicide for total control of weeds and mosses in a variety of agricultural and non-agricultural situations

Example pests controlled

Bermudagrass; Fathen; Pigweed; Charlock; Sowthistle; Wild radish; Wild turnip; Capeweed; Deadnettles; Poppies; Barnyard grass

Example applications

Vegetables including asparagus, peas, pulses; Fruit including bananas, pineapples, grapes; Cotton; Lucerne; Lupins; Sugarcane; Cereals including wheat, barley, oats, triticale; Tea; Ornamentals including tulips, daffodils, iris

Efficacy & activity

Efficiacy fully demonstratedvia field trials and through extensive use.

Availability status

Current

Introduction & key dates

circa 1951, introduced

UK regulatory status

UK COPR regulatory status

Not approved

Date COPR inclusion expires

Expired

UK LERAP status

No UK approval for use

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Germany/Denmark

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

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

Australia, USA

Chemical structure

Isomerism

None

Chemical formula

C₉H₁₀Cl₂N₂O

Canonical SMILES

CN(C)C(=O)NC1=CC(=C(C=C1)Cl)Cl

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

XMTQQYYKAHVGBJ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C9H10Cl2N2O/c1-13(2)9(14)12-6-3-4-7(10)8(11)5-6/h3-5H,1-2H3,(H,12,14)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
diuron	-

General status

Pesticide type

Herbicide

Substance groups

Phenylurea herbicide; Urea herbicide

Minimum active substance purity

970 g kg⁻¹

Known relevant impurities

EU dossier - 3,4-dichloroaniline; 2,4,3',4'-tetrachloroazoxybenzene; 3,4,3',4'-tetratchloroazobenzene

Substance origin

Synthetic

Mode of action

Systemic, absorbed via roots, acts by strongly inhibiting photosynthesis

CAS RN

330-54-1

EC number

206-354-4

CIPAC number

100

US EPA chemical code

035505

PubChem CID

3120

CLP index number

006-015-00-9

Molecular mass

233.09

PIN (Preferred Identification Name)

N'-(3,4-dichlorophenyl)-N,N-dimethylurea

IUPAC name

3-(3,4-dichlorophenyl)-1,1-dimethylurea

CAS name

N'-(3,4-dichlorophenyl)-N,N-dimethylurea

Other status information

WFD priority substance; Potential groundwater contaminant; Possible drinking water contaminant

Relevant Environmental Water Quality Standards

EU Directive 2008/105/EC EQS surface waters: annual average 0.2 µg l⁻¹; max measured 1.8 µg l⁻¹
UK Environment Agency non-statutory standard for the protection of aquatic life in freshwater and saltwater: 2 µg l⁻¹ as annual average; Freshwater 20 µg l⁻¹ as max acceptable conc.

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

Off-white powder

Formulations

Property

Value

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

Bayer Environ
Headland
Makhteshim-Agan
Nomix Environ
Nufarm
CropSure Pty Ltd

Example products using this active

Divide
Diurex
Freeway
Karmex
Diuron 900DF
Diuron 80% SC
CropSure Diuron 900WG

Formulation and application details

Often supplied as a soluble concentrate or wettable powder that is mixed with water and applied as a spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

35.6

ar 35 °C

Low

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

1470

o-Xylene

47200

Acetone

19000

Ethyl acetate

14400

1,2-Dichloroethane

Melting point (°C)

157.2

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

330

Flashpoint (°C)

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

7.41 X 10⁰²

Calculated

Log P

2.87

Moderate

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data

Density (g ml⁻¹)

1.5

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

1.15 X 10^-03

Low volatility

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

2.00 X 10^-06

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Neutral pH: 210nm=29414, 248nm=18516, 290nm=1002
Acidic pH: 211nm=29433, 248nm=18697
Basic pH: 220nm=21465, 248nm=16935

Surface tension (mN m⁻¹)

72.1

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Not readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

146.6

Persistent

DT₅₀ (lab at 20 °C)

146.6

Persistent

DT₅₀ (field)

229

Persistent

DT₉₀ (lab at 20 °C)

516.1

Very persistent

DT₉₀ (field)

2000

DT₅₀ modelling endpoint

116.5

normalised geometric mean of lab studies dark aerobic conditions

Note

EU dossier 2018 lab studies DT₅₀ range 27.3-472 days, DT₉₀ range 90.8-1570 days, soils=7; field studies DT₅₀ range 54-792 days, DT₉₀ range 180 - >10,000 days, Soils=6 days, 7 soils

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

Stable

Note

Stable pH 4 to pH 9

Water-sediment DT₅₀ (days)

Moderately fast

Water phase only DT₅₀ (days)

8.8

Moderately fast

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.

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

12.8

Slightly mobile

K_oc

680

Notes and range

EU 2018 dossier K_d range 7.7-20.4 mL g⁻¹, K_oc range 543-956 mL g⁻¹; Other sources: K_oc = 238-1750 mL g⁻¹, Soils=10

Freundlich

K_f

7.0

Slightly mobile

K_foc

757

¹/_n

0.75

Notes and range

EU 2018 dossier kf range 4.48-12.52 mL g⁻¹, K_foc range 293-504 mL g⁻¹, ¹/_n range 0.67-0.89, Soils=5; Other sources: K_foc range 293-909 mL g⁻¹, Soils=14

pH sensitivity

None

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.65

Calculated

Transition state

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

Value

2.05 X 10^-01

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

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

23.59

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)

9.45

Whole body

Low potential

CT₅₀ (days)

Not available

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

1-(3,4-dichlorophenyl)-3-methylurea

Major fraction

0.330

3,4-dichlorophenyl urea

Major fraction

0.245

3,4-dichloroaniline

Minor fraction

0.02

N'-(3-chlorophenyl)-N,Ndimethylurea (Ref: mCPDMU)

Minor fraction

Known groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

N'-(3-chlorophenyl)-N,Ndimethylurea

mCPDMU

Surface water

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 2000

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)

Birds - Acute LD₅₀ (mg kg⁻¹)

1104

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

1730 mg kg feed⁻¹

Colinus virginianus

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

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

> 798

Eisenia foetida

Moderate

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

15.78

Eisenia foetida corr

Moderate

Soil micro-organisms

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

Dose: 4 kg ha⁻¹

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

22.35

Folsomia candida

Non-target plants

4.15

Lycopersicom esulentum
Vegetative vigour, ER₅₀
as g ha⁻¹

136

Lycopersicom esulentum
Seedling emergence, ER₅₀
as g ha⁻¹

Honeybees (Apis spp.)

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

> 101.7

Apis mellifera

Low

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

> 86.75

Apis mellifera

Moderate

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

Chronic as 10-day LC₅₀ µg bee⁻¹ day⁻¹

> 30.51

Apis mellifera

Bumblebees (Bombus spp.)

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

> 500

Bombus terrestris

Low

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

> 445.8

Bombus terrestris

Low

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 at dose 5 kg ha⁻¹

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as % Mortality at dose 5 kg ha⁻¹

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)

> 4.1

Oncorhynchus mykiss

Moderate

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

0.41

Oncorhynchus mykiss 28 day

Moderate

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

6.98

Danio rerio Embryo

Moderate

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

5.7

Daphnia magna

Moderate

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

0.096

Daphnia magna

Moderate

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

> 0.9

Ceriodaphnia dubia

Moderate

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

1.1

Americamysis bahia

Moderate

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)

0.0183

Lemna gibba

Moderate

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

0.0027

Scenedesmus quadricauda

High

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)

> 2000

Rat

Low

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

5000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 0.26 / 7.1

Rat (aerosol/dust)

Other Mammal toxicity endpoints

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

0.007

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

0.016

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

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

0.007

Dermal penetration studies (%)

0.5-7.0

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Risks to bystanders and residents estimated to be low considering current use profile

Occupational

Risks of exposure identified via modelling - PPE/PPC essential

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Mammalian dose elimination route and rate

Rapid and extensive as metabolites mainly via urine (68-87%).

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

Possible blood, kidney, bladder, spleen and liver toxicant
Endocrine issues - Inhibition of androgens action
US EPA - likely human carcinogen; CLP data - suspected carcinogen

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Hazard Class 9
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H302, H351, H373
Environment: H400, H410

WHO Classification

III (Slightly hazardous)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Chemically stable under standard ambient conditions

TRANSLATIONS

Language

Name

English

diuron

French

diuron

German

Diuron

Danish

diuron

Italian

diuron

Spanish

diuron

Greek

diuron

Polish

diuron

Swedish

Hungarian

diuron

Dutch

diuron

Norwegian

Record last updated:	15/03/2024
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