Imazosulfuron (Ref: TH 913)

Imazosulfuron (Ref: TH 913)	Last updated: 21/08/2024
(Also known as: URA-09800-H-0-WG)

SUMMARY

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: Potential for particle bound transport: High	Ecotoxicity Moderate alert: Birds chronic ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Bees acute oral ecotoxicity: Moderate	Human health Moderate alert: Mammals chronic toxicity: Moderate; Reproduction/development effects

GENERAL INFORMATION

Description

A herbicide used to control most annual and perennial broad-leaved weeds in rice and some other crops

Example pests controlled

Sedges including yellow nutsedge, Hemp sesbania, Broad-leaved weeds

Example applications

Turf; Rice; Tomatoes; Peppers; Cereals including wheat, barley, rye and triticale

Efficacy & activity

Availability status

Current

Introduction & key dates

1994, introduced

UK regulatory status

UK COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

UK LERAP status

No UK approval for use as a pesticide

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Slovenia/Finland

Date EC 1107/2009 inclusion expires

Not applicable

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

Chemical structure

Isomerism

None

Chemical formula

C₁₄H₁₃ClN₆O₅S

Canonical SMILES

COC1=CC(=NC(=N1)NC(=O)NS(=O)(=O)C2=C(N=C3N2C=CC=C3)Cl)OC

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

NAGRVUXEKKZNHT-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C14H13ClN6O5S/c1-25-9-7-10(26-2)18-13(17-9)19-14(22)20-27(23,24)12-11(15)16-8-5-3-4-6-21(8)12/h3-7H,1-2H3,(H2,17,18,19,20,22)

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance groups

Sulfonylurea herbicide; Pyrimidylsulfonylurea herbicide

Minimum active substance purity

>93%, 980 g kg⁻¹

Known relevant impurities

EC RAR 2016: None declared

Substance origin

Synthetic

Mode of action

Inhibits plant growth, absorbed through roots and translocated throughout the plant. Inhibits plant amino acid synthesis - acetohydroxyacid synthase AHAS

CAS RN

122548-33-8

EC number

602-788-7

CIPAC number

590

US EPA chemical code

118602

PubChem CID

92433

CLP index number

No data found

Molecular mass

412.83

PIN (Preferred Identification Name)

IUPAC name

1-(2-chloroimidazo[1,2-a]pyridin-3-ylsulfonyl)-3-(4,6-dimethoxypyrimidin-2-yl)urea

CAS name

2-chloro-N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]imidazo[1,2-a]pyridine-3-sulfonamide

Other status information

Relevant Environmental Water Quality Standards

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

Lindernia dubia

Physical state

Whte crystalline powder

Formulations

Property

Value

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

Sumitomo Chemical Co. Ltd.

Example products using this active

Takeoff
League
Imazosulfuron 50 WG

Formulation and application details

Available as water dispersible granules or as a suspension concentrate

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

429.0

Moderate

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

2200

Ethyl acetate

4479

Acetone

400

Xylene

12745

Dichloromethane

Melting point (°C)

183.5

Boiling point (°C)

198

Degradation point (°C)

195

Flashpoint (°C)

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

8.51 X 10^-01

Calculated

Log P

-0.07

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.53

Dissociation constant pKa) at 25 °C

0.30

pKa(II)=3.94; Strong acid

Vapour pressure at 20 °C (mPa)

3.5 X 10^-03

Low volatility

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

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

57.31

Moderately persistent

DT₅₀ (lab at 20 °C)

57.31

Moderately persistent

DT₅₀ (field)

Moderately persistent

DT₉₀ (lab at 20 °C)

600

Very persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Lab studies DT₅₀ range 21-75 days, field study range 21-91 days (Germany)

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

3.1

Moderately fast

Note

pH 4 DT₅₀=8.5 days

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

Value

Stable

Note

pH 4: DT₅₀ 7.0 days; Stable at pH 9 DT₅₀ > 1 year

Water-sediment DT₅₀ (days)

120

Slow

Water phase only DT₅₀ (days)

257

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)

3.36

Slightly mobile

K_foc (mL g⁻¹)

1415

¹/_n

0.93

Notes and range

EU dossier K_f range 0.76-4.49 mL g⁻¹, K_foc range 76-4490 mL g⁻¹, ¹/_n range 0.86-1.02, Soils=5; RAR 2016 K_foc 135-428 mL g⁻¹, ¹/_n 0.78-0.89, Soils=5

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.48

Calculated

Low leachability

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

Value

3.91 X 10^-02

Calculated

Note

Potential for particle bound transport index

High

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

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

1.248

Calculated using the Atkinson method

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)

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

1-(2-chloroimidazol(1,2-a)pyridine-3-yl-sulfonyl)-3-(4-hydroxy-6-methoxypyrimidin-2-yl)urea

Major fraction

0.127

2-chloroimidazol(1,2-a)pyridine-3-sulfonamide

Major fraction

0.258

N-(((amino(imino)methyl)amino)carbonyl)-2-chloroimidazo(1,2-a)pyridine-3-sulfonamide

Minor fraction

0.056

2-amino-4,6-dimethoxypyrimidine

2-amino-4-hydroxy-6-methoxypyrimidine

Minor fraction

0.056

Anaerobic

(4,6-dimethoxypyridine-2-yl)aminocarbonylsulfamic acid

Anaerobic

4,6-dimethoxy-2-ureidopyrimidine

Photolysis

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)

1-(2-chloroimidazol(1,2-a)pyridine-3-yl-sulfonyl)-3-(4-hydroxy-6-methoxypyrimidin-2-yl)urea

Relevancy unknown

2-chloroimidazol(1,2-a)pyridine-3-sulfonamide

Relevancy unknown

2-amino-4,6-dimethoxypyrimidine

Relevancy unknown

4,6-dimethoxy-2-ureidopyrimidine

Relevancy unknown

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

2-amino-4,6-dimethoxypyrimidine

ADPM

Rat; Water

2-cyano-4,6-dimethoxypyrimidne

CDPM

Water (photolysis)

1(2-chloroimidazol(1,2-a)pyridine-3-yl-sulfonyl)-3-(4-hydroxy-5,6-dimethoxypyrimidine-2-yl)urea

HDS

Rat

1(2-chloroimidazol(1,2-a)pyridine-3-yl-sulfonyl)-3-(5-hydroxy-4,6-dimethoxypyrimidine-2-yl)urea

IHDU

Rat

2-(2-imino-1,2-dihydropyridin-1-yl)oxalic acid

IHOA

Water (photolysis)

(4,6-dimethoxypyridine-2-yl)aminocarbonylsulfamic acid

SDPM

Water (photoylsis)

4,6-dimethoxy-2-ureidopyrimidine

UDPM

Rat; Water (photolysis)

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

106

Rat 2 yr

Moderate

(ppm diet)

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

77.8

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2250

Anas platyrhynchos

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

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

< 25

Anas platyrhynchos NOED

Moderate

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

> 1000

Eisenia foetida

Low

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

500

Eisenia foetida

Low

Soil micro-organisms

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

Dose: 25 mg kg⁻¹ soil 56 Day

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

> 1000

Folsomia candida

Non-target plants

> 500

Avena sativa
Seedling emergence, ER₅₀
as g ha⁻¹

> 50

Avena sativa
Vegetative vigour, ER₅₀
as g ha⁻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)

> 41.6

Apis mellifera

Moderate

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

Chronic

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) as Mortality LR₅₀ g ha⁻¹

> 50

Aphidius rhopalosiphi

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

> 50

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)

> 100

Oncorhynchus mykiss

Low

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

2.9

Pimephales promelas 32 day

Moderate

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

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

> 91

Daphnia magna

Moderate

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

1.2

Daphnia magna

Moderate

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)

0.49

Chironomus riparius

Moderate

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

3.0

Chironomus riparius

Moderate

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

0.00075

Lemna gibba

High

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

0.69

Pseudokirchneriella subcapitata

Moderate

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)

> 5000

Rat

Low

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 2.12

Rat (nose only)

Other Mammal toxicity endpoints

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

0.75

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

None allocated

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

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

0.53

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

[Low risk when used as prescribed]

Exposure Routes

Public

Negligible risk when used as prescribed

Occupational

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

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 liver & thyroid toxicant

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Environment: H400, H410

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

imazosulfuron

French

imazosulfuron

German

Imazosulfuron

Danish

imazosulfuron

Italian

imazosulfuron

Spanish

imazosulfuron

Greek

Polish

imazosulfuron

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	21/08/2024
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