Clomazone (Ref: FMC 57020)

Clomazone (Ref: FMC 57020)	Last updated: 12/01/2021
(Also known as: dimethazone; fenoxan )

GENERAL INFORMATION

Description

Used for the control of broad-leaved weeds and grasses in a range of crops

Example pests controlled

Nightshade; Pigweed; Potato weed; Fathen; Hogweed; Wild radish; Staggerweed

Example applications

Cotton; Vegetables including peas, potatoes, sweet potatoes, green beans, navy beans; Curcubits; Tobacco; Rice; Oilseed rape

Efficacy & activity

Efficiacy demonstrated through field trials and extensive use.

Availability status

Current

Introduction & key dates

circa 1985

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/10/2024

UK LERAP status

None

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Denmark/Germany

Date EC 1107/2009 inclusion expires

31/10/2021

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, USA

Chemical structure

Isomerism

Chemical formula

C₁₂H₁₄ClNO₂

Canonical SMILES

CC1(CON(C1=O)CC2=CC=CC=C2Cl)C

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

KIEDNEWSYUYDSN-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C12H14ClNO2/c1-12(2)8-16-14(11(12)15)7-9-5-3-4-6-10(9)13/h3-6H,7-8H2,1-2H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance group

Isoxazolidinone

Minimum active substance purity

960 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Selective, absorbed by roots and shoots. Inhibition of lycopene cyclase.

CAS RN

81777-89-1

EC number

CIPAC number

509

US EPA chemical code

125401

PubChem CID

54778

Molecular mass

239.7

PIN (Preferred Identification Name)

2-[(2-chlorophenyl)methyl]-4,4-dimethyl-1,2-oxazolidin-3-one

IUPAC name

2-(2-chlorobenzyl)-4,4-dimethyl-1,2-oxazolidin-3-one

CAS name

2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Classification (HRAC)

Herbicide Resistance Classification (WSSA)

Insecticide Resistance Classification (IRAC)

Not applicable

Fungicide Resistance Classification (FRAC)

Not applicable

Examples of recorded resistance

Lolium rigidum

Physical state

Pale straw coloured liquid

Formulations

Property

Value

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

Centium 36 CS
Command
Gamit
Clone

Example products using this active

Belchim
Greencrop
FMC Corp
Agriguard

Formulation and application details

Often available as a capsule suspension that is mixed with water and used as a spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

1212

High

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

250000

Acetone

955000

Dichloromethane

161800

n-Heptane

969000

Methanol

Melting point (°C)

33.9

Boiling point (°C)

281.7

Degradation point (°C)

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

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

3.80 X 10⁰²

Calculated

Log P

2.58

Low

Bulk density (g ml⁻¹)

1.19

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

27.0

Highly volatile

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

5.9 X 10^-03

Non-volatile

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

Neutral pH: 195.5nm=28437.1, 210nm=14539.4
Acid pH: 201.5nm=15338.4, 210nm=14406.2
Basic pH; 197.5=24091.1, 210nm=14551.5

Surface tension (mN m⁻¹)

45.98

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

22.6

Non-persistent

DT₅₀ (lab at 20 °C)

22.6

Non-persistent

DT₅₀ (field)

27.3

Non-persistent

DT₉₀ (lab at 20 °C)

135.3

Persistent

DT₉₀ (field)

262

DT₅₀ modelling endpoint

Note

EU 2018 dossier lab studies DT₅₀ (normalised) range 6.3-145.7 days,DT₉₀ range 32.3-617 days, Soils=28; field studies DT₅₀ (normalised) range: 9.3-195 days, DT₉₀ range 65.4-645 days,Soils=19

Dissipation rate RL₅₀ on plant matrix

Value

Note

Dissipation rate RL₅₀ 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 pH 5 to pH 9, 25 °C

Water-sediment DT₅₀ (days)

Moderately fast

Water phase only DT₅₀ (days)

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

Moderately mobile

K_oc

300

Notes and range

Freundlich

K_f

2.08

Moderately mobile

K_foc

128.3

¹/_n

0.90

Notes and range

EU 2018 dossier K_f range 0.45-4.04 mL g⁻¹, K_foc range 33-317 mL g⁻¹, ¹/_n range 0.81-0.99, Soils=20

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.72

Calculated

Transition state

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

Value

1.79 X 10^-01

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

(N-((2-chlorobenzyl))-3-hydroxy-2,2-dimethylpropanamide) (Ref: FMC 653167)

Soil

0.250

Major fraction, Relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

N-[(2-chlorobenzyl)]-2-methyl propanamide (Ref: FMC 55657)

Water; Water/sediment

isoxazolidine (Ref: FMC 57091)

Plant

5-keto-clomazone

Plant

hydroxy-clomazone

Plant

hydroymethyl clomazone

Plant

hydroxy-2-chlorobenzyl alcohol

Plant

2-chlorobenzoic acid

Plant

2-chlorobenzyl alcohol (Ref: FMC 61569)

OCB-alcohol

Plant

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

Whole fish

Low potential

CT₅₀ (days)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

754

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

13.3

Rat

High

(ppm diet)

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

314

Rat Reproductive NOAEL

Low

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2224

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5620 ppm

Colinus virginianus

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

76.5

Colinius virginianus NOEC

Moderate

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

14.4

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

2.30

Oncorhynchus mykiss

Moderate

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

12.7

Daphnia magna

Moderate

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

2.2

Daphnia magna

Moderate

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

0.53

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)

60.5

Chironomus riparius

Moderate

Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)

34.0

Lemna gibba

Low

Non-target plants

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

0.136

Navicula pelliculosa 120 hour

Moderate

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

0.05

Navicula pelliculosa 120 hour

Moderate

Honeybees (Apis spp.)

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

> 89.5

Apis mellifera

Moderate

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

> 76.33

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)

> 968

Bombus terrestris

Low

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

> 968

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 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 corr

Moderate

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

> 0.8

Eisenia foetida

Moderate

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

11.3

Folsomia candida

Other arthropod (1)

LR₅₀ g ha⁻¹

120

>
Typhlodromus pyri

% Effect

5 / 0

Mortality / Fecundity [Dose: 0.32 kg ha⁻¹]
Aphidius rhopalosiphi

Other arthropod (2)

LR₅₀ g ha⁻¹

120

.
Aphidius rhopalosiphi

% Effect

4.3 / 29.1

Mortality / Fecundity [Dose: 0.32 kg ha⁻¹]
Typhlodromus pyri

Soil micro-organisms

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

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)

754

Rat

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

4.3

Rat 4 hr (whole body)

Other Mammal toxicity endpoints

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

0.12

Dog SF=100

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

2.5

Rat SF=100

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

2.5

Rat SF=100

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

0.12

Dog SF=100

Dermal penetration studies (%)

25-75

concentration dependant

Dangerous Substances Directive 76/464

Exposure Routes

Public

Minor risk to residents and bystanders considering expected patterns of use

Occupational

PPE/PPC advised

European MRLs

EU MRL pesticide database

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Moderately toxic
Possible liver toxicant

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Code is usually 6.1

CLP classification 2013

Health: H302, H312, H315, H319, H332
Environment: H400, H410, H411, H412

EC Risk Classification

Xn - Harmful: R20/22,N - Dangerous for the environment: R50/53

EC Safety Classification

WHO Classification

II (Moderately hazardous)

UN Number

Usually 2902

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

Language

Name

English

clomazone

French

clomazone

German

Clomazone

Danish

clomazone

Italian

clomazone

Spanish

clomazona

Greek

Polish

chlomazon

Swedish

klomazon

Hungarian

klomazon

Dutch

clomazone

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