Bensulfuron (Ref: IN R9419)

Bensulfuron (Ref: IN R9419)	Last updated: 28/07/2025
(Also known as: free acid bensulfuron-methyl)

SUMMARY

Bensulfuron is a herbicide normally used as the methyl variant. It is not expected to be persistent in soil and as it is considered moderately mobile there are some risks of leaching to groundwater. Based on its physico-chemical properties there may also be a risk of bio-concentration. Its is moderately toxic to aquatic plants and to earthworms.

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 Moderate alert: Fish acute ecotoxicity: Moderate; Bees acute oral ecotoxicity: Moderate	Human health Moderate alert: Reproduction/development effects

GENERAL INFORMATION

Description

A pyrimidinylsulfonylurea herbicide used to control annual and perennial weeds and sedges. Usually used as the methyl variant. Pesticide transformation product.

Example pests controlled

Pigweed; Chickweed; Wild mustard; Stinkgrass; Barnyardgrass; Rice flatsedge; Dwarf umbrella grass; Nut-grass; Creeping water primrose

Example applications

Cereals especially wheat; Rice

Efficacy & activity

Availability status

Current

Introduction & key dates

1985, introduced

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

31/10/2031

GB LERAP status

No UK approval for use as a plant protection agent

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Italy/Spain

Date EC 1107/2009 inclusion expires

15/08/2026

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

C₁₅H₁₆N₄O₇S

Canonical SMILES

COC1=CC(=NC(=N1)NC(=O)NS(=O)(=O)CC2=CC=CC=C2C(=O)O)OC

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

PPWBRCCBKOWDNB-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C15H16N4O7S/c1-25-11-7-12(26-2)17-14(16-11)18-15(22)19-27(23,24)8-9-5-3-4-6-10(9)13(20)21/h3-7H,8H2,1-2H3,(H,20,21)(H2,16,17,18,19,22)

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide; Metabolite

Metabolite Type

Soil; Surface water; Sediment; Groundwater

Substance groups

Sulfonylurea herbicide; Pyrimidinylsulfonylurea herbicide

Minimum active substance purity

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Selective, systemic action being absorbed through foliage and roots. Inhibits plant amino acid synthesis - acetohydroxyacid synthase AHAS

CAS RN

99283-01-9

EC number

874-914-0

CIPAC number

502

US EPA chemical code

Not listed

PubChem CID

107828

CLP index number

607-178-00-4

Molecular mass

396.38

PIN (Preferred Identification Name)

2-({[(4,6-dimethoxypyrimidin-2-yl)carbamoyl]sulfamoyl}methyl)benzoic acid

IUPAC name

α-[(4,6-dimethoxypyrimidin-2-ylcarbamoyl)sulfamoyl]-o-toluic acid

CAS name

2-[[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]methyl]benzoic acid

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

Physical state

Related substances & organisms

bensulfuron-methyl

Formulations

Property

Value

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

DuPont

Example products using this active

Formulation and application details

Usually formulated as the methyl variant

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

as methyl variant

Moderate

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

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

6.17 X 10⁰⁰

Calculated

Log P

0.79

as methyl variant

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.52

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

4.99 X 10^-03

as methyl variant

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

Not readily biodegrdable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

27.8

Non-persistent

DT₅₀ (lab at 20 °C)

27.8

Non-persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

129.3

Persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU 2022 dossier lab studies DT₅₀ (normalised) range 21.4-74.6 days, DT₉₀ (measured) range 26.8-277 days, Soils=1

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

Note

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

Value

Note

Water-sediment DT₅₀ (days)

5.2

Fast

Water phase only DT₅₀ (days)

8.0

Moderately fast

Sediment phase only DT₅₀ (days)

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)

8.8

Moderately mobile

K_foc (mL g⁻¹)

226

¹/_n

0.9

Notes and range

EU dossier K_f range 0.3-17.4 mL g⁻¹, K_foc range 28-580 mL g⁻¹, ¹/_n range 0.89-0.93, Soils=5

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.38

Calculated

Transition state

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

Value

1.16 X 10^-01

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

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

methyl 2-({[(4-hydroxy-6-methoxypyrimidin-2-yl)carbamoyl]sulfamoyl}methyl)benzoate (Ref: IN-F7880)

Minor fraction

0.043

methyl 2-(sulfamoylmethyl)benzoate (Ref: IN-N5297)

Major fraction

0.210

2-((aminosulfonyl)methyl)benzoic acid (Ref: IN D1R84)

Major fraction

0.182

2-amino-4,6-dimethoxypyrimidine (Ref: AE-F092944)

Major fraction

0.460

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)

methyl 2-(sulfamoylmethyl)benzoate (Ref: IN-N5297)

Relevancy unknown

(4,6-dimethoxypyrimidin-2-yl)urea (Ref: IN-T5831)

Relevancy unknown

{[(4,6-dimethoxypyrimidin-2-yl)carbamoyl]sulfamoyl}acetic acid (Ref: IN-DAT97)

Relevancy unknown

Other known metabolites

None

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)

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2510

Anas platyrhynchos as methyl variant

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

> 1000

Eisenia foetida

Low

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

230

Eisenia andrei as mg ha⁻¹

Low

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

> 60

3 plant species tested as methyl variant

Seedling emergence ER₅₀ (g ha⁻¹)

> 60

3 plant species tested as methyl variant

Honeybees (Apis spp.)

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

> 100

Apis mellifera as methyl variant

Low

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

> 51.4

Apis mellifera as methyl variant

Moderate

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

Chronic

Notes

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, Std lab test

> 600

Aphidius rhopalosiphi as methyl variant

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹, Std lab test

> 600

Typhlodromus pyri Adult as methyl variant

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)

> 66

Oncorhynchus mykiss as methyl variant

Moderate

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

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

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

130

Daphnia magna as methyl variant

Low

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

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 (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹) (ErC₅₀, Static)

7.61

Lemna gibba

Moderate

Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)

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

26.4

Pseudokirchneriella subcapitata

Low

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

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

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)

2000

Rat as methyl variant

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

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

0.2

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)

0.12

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

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

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Possible liver toxicant

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: H317
Environment: H411

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

bensulfuron

French

bensulfuron

German

Bensulfuron

Danish

bensulfuron

Italian

bensulfuron

Spanish

bensulfuron

Greek

Polish

bensulfuron

Swedish

Hungarian

benszulforon

Dutch

Norwegian

Record last updated:	28/07/2025
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