Siduron

Siduron	Last updated: 09/03/2021
(Not known by any other names)

SUMMARY

Siduron is a selective pre-emergence herbicide without EU regulatory approval for use. It has a low aqueous solubility, is volatile and, based on its chemical properties, it is moderately mobile with has a high potential to leach to groundwater. It is persistent in both soil and water systems. It has a relatively low mammalian toxicity and would not be expected to bioaccumulate. It is classified as an irritant. It is not highly toxic to birds, is moderately toxic to fish, algae and honey bees.

GENERAL INFORMATION

Description

A pre-emergence herbicide used to control Digitaria spp. and other grass weeds used mainly for non-agricultural applications

Example pests controlled

Crabgrass; Downy brome; Foxtail; bentgrass; Fescue; Ryegrass; Canarygrass

Example applications

Golf courses; Sports fields; Sod farms and grass seed production; Roadsides; Parks

Efficacy & activity

Availability status

Current

Introduction & key dates

1994

UK regulatory status

UK COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

UK LERAP status

No UK approval for use

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Not applicable

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

Also used in

Australia

Chemical structure

Isomerism

A chiral molecule. The technical material is an isomeric mixture of the cis-and trans-isomers.

Chemical formula

C₁₄H₂₀N₂O

Canonical SMILES

CC1CCCCC1NC(=O)NC2=CC=CC=C2

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

JXVIIQLNUPXOII-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C14H20N2O/c1-11-7-5-6-10-13(11)16-14(17)15-12-8-3-2-4-9-12/h2-4,8-9,11,13H,5-7,10H2,1H3,(H2,15,16,17)

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance group

Phenylurea

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Selective, absorbed by roots and translocated. Photosynthetic electron transport inhibitor at the photosystem II.

CAS RN

1982-49-6

EC number

217-844-2

CIPAC number

321

US EPA chemical code

035509

PubChem CID

16116

Molecular mass

232.32

PIN (Preferred Identification Name)

N-(2-methylcyclohexyl)-N'-phenylurea

IUPAC name

1-(2-methylcyclohexyl)-3-phenylurea

CAS name

N-(2-methylcyclohexyl)-N'-phenylurea

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

Colourless, odourless crystals

Formulations

Property

Value

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

Tupersan

Example products using this active

Gowan Co.
Raschig

Formulation and application details

Usually formulated as a wettable powder and applied as a pre-emergence treatment to bare soil. It may also be formulated as a mixture with fertilisers.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

22.3

Low

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

Melting point (°C)

136

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

2.70 X 10⁰⁰

Calculated

Log P

0.431

Low

Bulk density (g ml⁻¹)

1.08

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

5.30 X 10^-04

Low volatility

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

6.80 X 10^-06

Non-volatile

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)

135

Persistent

DT₅₀ (lab at 20 °C)

Moderately persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Best available data

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

290

Stable

Note

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

Value

Stable

Note

Water-sediment DT₅₀ (days)

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

420

Notes and range

Freundlich

K_f

K_foc

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.69

Calculated

Transition state

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

Value

2.11 X 10^-01

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

methylcyclohexylurea

Soil

Not assessed under 91/414 or 1107/2009

methylcyclohexylamine

Soil

Not assessed under 91/414 or 1107/2009

phenylurea (Ref: IN-B5685)

Soil

0.170

Not assessed under 91/414 or 1107/2009

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

Estimated

Low potential

CT₅₀ (days)

Not available

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 7500

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat 2 year

(ppm diet)

500

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 10000

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

8.1

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

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

> 13.7

Daphnia magna

Moderate

Aquatic invertebrates - Chronic 21 day NOEC (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)

Non-target plants

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

> 0.25

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)

120

Low

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

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)

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

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Other arthropod (1)

LR₅₀ g ha⁻¹

% Effect

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

Soil micro-organisms

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)

> 7500

Rat

Low

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

5500

Rabbit

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 5.8

Rat

Other Mammal toxicity endpoints

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

0.14

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

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

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

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

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

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

No further information available

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

Health: H315, H319
Environment: H410, H412

EC Risk Classification

Xi - Irritant: R36/37/38
N - Dangerous for the environment: R52/53

EC Safety Classification

S26, S61

WHO Classification

U (Unlikely to present an acute hazard)

UN Number

Waste disposal & packaging

TRANSLATIONS

Language

Name

English

siduron

French

siduron

German

Siduron

Danish

siduron

Italian

siduron

Spanish

siduron

Greek

Polish

siduron

Swedish

Hungarian

Dutch

Record last updated:	09/03/2021
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