Mesotrione (Ref: ZA 1296)

Mesotrione (Ref: ZA 1296)	Last updated: 18/02/2021
(Not known by any other names)

GENERAL INFORMATION

Description

A pre-emergence and post-emergence herbicide used to control some grass and broad-leaved weeds mainly in maize crops

Example pests controlled

Broad-leaved weeds including velvet leaf, cocklebur, pigweeds, sunflower and nightshades

Example applications

Maize; Sweetcorn; Flax; Asparagus; Fruit including cranberry, blueberry, rhubarb

Efficacy & activity

Availability status

Current

Introduction & key dates

2001

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/05/2032

UK LERAP status

Buffer probably required in UK - see product label

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

UK/Belgium

Date EC 1107/2009 inclusion expires

31/05/2032

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

Chemical structure

Isomerism

None

Chemical formula

C₁₄H₁₃NO₇S

Canonical SMILES

CS(=O)(=O)C1=CC(=C(C=C1)C(=O)C2C(=O)CCCC2=O)[N+](=O)[O-]

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

KPUREKXXPHOJQT-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C14H13NO7S/c1-23(21,22)8-5-6-9(10(7-8)15(19)20)14(18)13-11(16)3-2-4-12(13)17/h5-7,13H,2-4H2,1H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance group

Triketone

Minimum active substance purity

930 g kg⁻¹

Known relevant impurities

EU dossier (2016) - 1-cyano-6-(methylsulfonyl)-7-nitro-9H-xanthen-9-one <2 mg kg⁻¹; 6-(methylsulfonyl)-9-oxo-9H-xanthene-1- carbonitrile <2 g kg⁻¹; 1,2-dichloroethane <1 g kg⁻¹

Substance origin

Synthetic

Mode of action

Selective, absorbed by roots and translocated. Bleaching: inhibition of 4-hydroxyphenyl-pyruvate-dioxygenase.

CAS RN

104206-82-8

EC number

609-064-00

CIPAC number

625

US EPA chemical code

122990

PubChem CID

175967

Molecular mass

339.32

PIN (Preferred Identification Name)

IUPAC name

2-(4-mesyl-2-nitrobenzoyl)cyclohexane-1,3-dione

CAS name

2-(4-(methylsulfonyl)-2-nitrobenzoyl)-1,3-cyclohexanedione

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

Physical state

Yellow to tan coloured solid

Related substances & organisms

terbuthylazine

Formulations

Property

Value

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

Calaris
Callisto
Marvel

Example products using this active

Greencrop
Syngenta
Chemsource

Formulation and application details

Often supplied as a soluble concentrate 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)

1500

High

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

93300

Acetone

18600

Ethyl acetate

3100

Toluene

1600

Xylene

Melting point (°C)

165.3

Boiling point (°C)

Decomposese before boiling

Degradation point (°C)

166

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

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

1.29 X 10⁰⁰

Calculated

Log P

0.11

Low

Bulk density (g ml⁻¹)

1.49

Dissociation constant pKa) at 25 °C

3.12

Weak acid

Vapour pressure at 20 °C (mPa)

5.70 X 10^-03

Low volatility

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

5.10 X 10^-07

Non-volatile

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

256nm = 22400, no maxima >290 nm

Surface tension (mN m⁻¹)

61.5

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

19.6

Non-persistent

DT₅₀ (lab at 20 °C)

19.6

Non-persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

46.0

Moderately persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier (2016) lab studies DT₅₀ range 4.0-44.3 days, DT₉₀ range 14.3-78.9 days, Soils=19; Field study DT₅₀ range 3-7 days, DT₉₀ range 36-78 days; Other sources: DT₅₀ 10 days (DW4)

Dissipation rate RL₅₀ on plant matrix

Value

Note

Dissipation rate RL₅₀ on and in plant matrix

Value

3.2

Note

Published literature RL₅₀ range 3.0-4.5 days, maize, various matrices, n=5

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Stable

Note

DT₅₀ 81-88 days at 40 deg N, 89-97 days at 50 deg N, both summer conditions

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

Value

Stable

Note

Stable pH 5 to pH 9 at 25 °C

Water-sediment DT₅₀ (days)

5.2

Fast

Water phase only DT₅₀ (days)

5.3

Moderately fast

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

1.62

Moderately mobile

K_oc

122

Notes and range

Literature data: K_d range 0.13-5.0 mL g⁻¹, K_oc range 15-390 mL g⁻¹, soils=15; Other data: K_oc: 390 mL g⁻¹ (DW3)

Freundlich

K_f

0.89

Moderately mobile

K_foc

83.3

¹/_n

0.940

Notes and range

EU dossier (2016) K_f range 0.16-6.16 mL g⁻¹, K_foc range 14-354 mL g⁻¹, Soils=10

pH sensitivity

Sorption decreases as pH increases.

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.45

Calculated

Low leachability

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

Value

4.13 X 10^-03

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

4-methylsulfonyl-2-nitrobenzoic acid

Soil

0.572

Minor fraction, Relevant

2-amino-4-methylsulfonylbenzoic acid

Soil

0.097

Minor fraction, Relevant

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

0.24

Rat

High

(ppm diet)

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

0.3

Rat Reproductive NOAEL

High

Birds - Acute LD₅₀ (mg kg⁻¹)

> 3776

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5200 mg kg feed⁻¹

Colinus virginianus

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

20.6

Anas platyrhynchos NOEL

Moderate

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

> 120

Lepomis macrochirus

Low

Fish - Chronic 21 day NOEC (mg l⁻¹)

12.5

Oncorhynchus mykiss 35 day

Low

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

> 622

Daphnia magna

Low

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

180

Daphnia magna

Low

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)

180

Chironomus riparius

Low

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

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

0.022

Lemna minor

Moderate

Non-target plants

0.833

Lactuca sativa
Vegetative vigour, ER₅₀
g ha⁻¹

13.8

Lactuca sativa
Seedling emergence, ER₅₀
g ha⁻¹

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

3.5

Raphidocelis subcapitata

Moderate

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

Honeybees (Apis spp.)

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

> 100

Apis mellifera

Low

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

> 11

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)

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 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)

> 2000

Eisenia foetida

Low

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

10.85

Eisenia foetida

Moderate

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

50.54

Folsomia candida

Other arthropod (1)

LR₅₀ g ha⁻¹

93.1

=
Typhlodromus pyri

% Effect

Other arthropod (2)

LR₅₀ g ha⁻¹

43.6

=
Aphidius rhopalosiphi

% Effect

3 / -9.3

Mortality / Parasitism [Dose: 0.2 kg ha⁻¹]
Aphidius rhopalosiphi adult

Soil micro-organisms

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

Dose: 0.4 kg ha⁻¹ 28 days

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)

> 5000

Rat

Low

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 4.75

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

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

0.01

Mouse SF=200

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

0.02

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

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

0.005

Mouse SF=400

Dermal penetration studies (%)

0.24-0.48

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

No unacceptable risks to operators or other workers identified

MRLs

European

EU MRL pesticide database

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

General human health issues

May damage the corneal opacity

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising

CLP classification 2013

Environment: H400, H410

EC Risk Classification

N - Dangerous for the environment: R50, R53

EC Safety Classification

S60, S61

WHO Classification

NL (Not listed)

UN Number

Usually 3077

Waste disposal & packaging

TRANSLATIONS

Language

Name

English

mesotrione

French

mesotrione

German

Mesotrione

Danish

mesotrion

Italian

mesotrione

Spanish

mesotriona

Greek

mesotrione

Polish

mezotrion

Swedish

mesotrion

Hungarian

mezotrion

Dutch

mesotrione

Record last updated:	18/02/2021
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