Chlorotoluron (Ref: C 2242)

Chlorotoluron (Ref: C 2242)	Last updated: 13/11/2024
(Also known as: chlortoluron; CTU)

SUMMARY

Chloroturon is a commonly used urea herbicide. It is moderately soluble in water, volatile with a high potential for leaching to groundwater. It is moderately persistent in soil but tends not to be persistent in water due to rapid aqueous photolysis. Chloroturon has a low mammalian toxicity but may bioaccumulate. Whilst it is non-toxic to honeybees it is moderately toxic to birds, earthworms and most aquatic organisms.

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 High alert: Birds chronic ecotoxicity: High	Human health Moderate alert: Mammals chronic toxicity: Moderate; Possible Carcinogen; Endocrine disrupter; Reproduction/development effects

GENERAL INFORMATION

Description

A contact and residual urea herbicide used to control broad-leaved weeds and grasses

Example pests controlled

Annual meadow grass; Black-grass; Nightshade; bindweed; Chickweed; Fat hen; Marigold; Speedwells; Knotgrass; Hemp-nettle; Dead-nettle; Common poppy; Mayweed

Example applications

Cereals including wheat, barley, rye, triticale; Potatoes; Maize; Vegetables including onions, carrot, parsnip; Fruit including blackcurrant, apples, pears, chrries, strawberry, gooseberry

Efficacy & activity

Efficacy established from field trials and extensive global use.

Availability status

Current

Introduction & key dates

1994, introduced

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

31/10/2027

GB LERAP status

Crop over 5m, Crop over 5m DRT - See Authorisation for Crop LERAP Details

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Belgium/France

Date EC 1107/2009 inclusion expires

15/08/2026

EU Candidate for substitution (CfS)

Yes - two 'Persistent-Bioaccumulative-Toxic' criteria

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

C₁₀H₁₃ClN₂O

Canonical SMILES

CC1=C(C=C(C=C1)NC(=O)N(C)C)Cl

Isomeric SMILES

International Chemical Identifier key (InChIKey)

JXCGFZXSOMJFOA-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C10H13ClN2O/c1-7-4-5-8(6-9(7)11)12-10(14)13(2)3/h4-6H,1-3H3,(H,12,14)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
chlorotoluron	-

General status

Pesticide type

Herbicide

Substance groups

Urea herbicide; Phenylurea herbicide

Minimum active substance purity

975 g kg⁻¹

Known relevant impurities

EU dossier - None publically declared

Substance origin

Synthetic

Mode of action

Selective, non-systemic absorbed by roots and foliage. Acts by the inhibition of photosynthetic electron transport.

CAS RN

15545-48-9

EC number

239-592-2

CIPAC number

217

US EPA chemical code

216500

PubChem CID

27375

CLP index number

616-105-00-5

Molecular mass

212.68

PIN (Preferred Identification Name)

N'-(3-chloro-4-methylphenyl)-N,N-dimethylurea

IUPAC name

3-(3-chloro-p-tolyl)-1,1-dimethylurea

CAS name

N'-(3-chloro-4-methylphenyl)-N,N-dimethylurea

Other status information

Marine Pollutant; Potential groundwater contaminant

Relevant Environmental Water Quality Standards

UK Environment Agency non-statutory standard for the protection of aquatic life: freshwater and saltwater annual average 2.0 µg l⁻¹, Freshwater max acceptable conc 20.0 µg l⁻¹

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

Alopecurus myosuroides

Physical state

Colourless crystals

Formulations

Property

Value

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

Clayton
Headland
Makhteshim-Agan
Nufarm UK

Example products using this active

Tolerate
Alpha Chlortoluron 500
Tolugan
Tolugan Extra
Dicurane

Formulation and application details

Usually supplied as a soluble concentrate or wettable granules that are 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)

76.0

Moderate

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

63000

Methanol

47000

Acetone

1600

Xylene

20000

Ethyl acetate

Melting point (°C)

148.05

Boiling point (°C)

292.2

Degradation point (°C)

Flashpoint (°C)

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

3.16 X 10⁰²

Calculated

Log P

2.5

Low

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data based on LogP

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

No dissociation

Vapour pressure at 20 °C (mPa)

0.008

Low volatility

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

9.07 X 10^-07

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Two absorption maxima at 241nm and 280nm. No absorption maximum between 340nm and 750nm

Surface tension (mN m⁻¹)

67.79

at 20 °C 99.9%

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Not readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

33.5

Moderately persistent

DT₅₀ (lab at 20 °C)

33.5

Moderately persistent

DT₅₀ (field)

12.5

Non-persistent

DT₉₀ (lab at 20 °C)

260

Persistent

DT₉₀ (field)

224

DT₅₀ modelling endpoint

33.5

(geometric mean)

Note

EU 2021 RAR: Lab studies DT₅₀ (normalised) range 10.3=144 days; DT₉₀ (measured) range 40.2-796 days, Soils=8; Field studies DT₅₀ (normalised) range 9.7-17.2 days, DT₉₀ (measured) range 145.6-346.1 days, Soils=5

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 at all environmentally pHs

Water-sediment DT₅₀ (days)

308.3

Slow

Water phase only DT₅₀ (days)

44.4

Stable

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)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

1.3

Moderately mobile

K_foc (mL g⁻¹)

147.22

¹/_n

0.877

Notes and range

EU 2021 RAR: K_f range 0.78-2.74 mL g⁻¹, K_foc range 121.4-177.1 mL g⁻¹, ¹/_n range 0.827-0.930, Soils=4

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.01

Calculated

Transition state

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

Value

4.78 X 10^-02

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

6.6

Calculated using the Atkinson method. Assumed 1.6E+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

desmethyl chlorotoluron (Ref: CGA 16339)

Major fraction

0.208

chlorotoluron benzoic acid (Ref: CGA 151400)

Minor fraction

0.08

Known groundwater metabolites

Metabolite

EC SANCO/221/2000 relevancy

ADI (mg kg⁻¹ bodyweight day⁻¹)

WHO drinking water guidance value (μg L⁻¹ day⁻¹)

chlorotoluron benzoic acid (Ref: CGA 151400)

Not relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Didesmethyl chlorotoluron (Ref: CGA 16340)

Surface water; Sediment

Desmethyl chlorotoluron benzoic acid (Ref: CGA 15139)

Surface water; Sediment

Didesmethyl chlorotoluron benzoic acid (Ref: CGA 14119)

Surface water

Hydroxydeschlorotoluron

Surface water

3-chloro-4-methylaniline

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)

> 5

Rat 2 yr

High

(ppm diet)

> 100

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

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

272

Coturnix japonica

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

> 2150 mg kg feed⁻¹

Coturnix japonica

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

9.6

Coturnix japonica

High

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

> 500

Eisenia foetida corr

Moderate

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

31.25

Eisenia foetida corr

Moderate

Soil micro-organisms

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

Dose: 3.5 kg ha⁻¹; 83 Day

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

195

folsomia candida

Non-target plants

Honeybees (Apis spp.)

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

> 200.2

Apis mellifera

Low

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

> 100.1

Apis mellifera

Low

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

Chronic as 10-day LDD₅₀ µg bee⁻¹ day⁻¹

21.18

Apis mellifera

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) as Mortality LR₅₀ g ha⁻¹

2.45

Chrysoperla carnea

Beneficial insects (Parasitic wasps) as Mortality LD₅₀ g ha⁻¹

2.45

Aphidius rhopalosiphi

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

2.45

Typhlodromus pyri

Beneficial insects (Ground beetles) as Mortality LR₅₀ g ha⁻¹

2.45

Poecilus cupreus

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

7.7

Oncorhynchus mykiss

Moderate

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

0.4

Oncorhynchus mykiss

Moderate

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

6.17

Danio rerio Embryo

Moderate

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

Daphnia magna

Moderate

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

11.2

Daphnia magna

Low

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)

0.038

Lemna gibba

Moderate

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

0.082

Pseudokirchneriella subcapitata

Moderate

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

> 0.8

Pseudokirchneriella subcapitata

Moderate

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves – LOEC (mg l⁻¹)

15.0

Crassostrea gigas

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)

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 5.3

Rat (nose only)

Other Mammal toxicity endpoints

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

0.04

Rat SF=100

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

None allocated

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

None allocated

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

0.215

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Acceptable risk to bystanders for proposed uses

Occupational

Acceptable risk to operators and other workers for proposed uses

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Non-statutory WHO drinking water guideline 0.03 mg l⁻¹

UK EA QS database 2018

Drinking Water MAC (μg l⁻¹)

Mammalian dose elimination route and rate

Excreted mainly in the urine (60-80%)

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

Kidney and liver tumors have been observed in Mouse at high doses - WHO
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: H351, H361d
Environment: H400, H410

WHO Classification

U (Unlikely to present an acute hazard)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

chlorotoluron

French

chlortoluron

German

Chlortoluron

Danish

chlorotoluron

Italian

clorotoluron

Spanish

clortoluron

Greek

chlorotoluron

Polish

chlorotoluron

Swedish

Hungarian

chlortoluron

Dutch

chloortoluron

Norwegian

Record last updated:	13/11/2024
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