Pendimethalin (Ref: AC 92553)

Pendimethalin (Ref: AC 92553)	Last updated: 25/07/2024
(Also known as: pendimethaline; penoxalin; phenoxalin)

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: Persistent; Potential for particle bound transport: High	Ecotoxicity High alert: Fish chronic ecotoxicity: High	Human health High alert: Reproduction/development effects

GENERAL INFORMATION

Description

A herbicide used to control most annual grasses and common weeds in cereals, fruit and vegetables

Example pests controlled

Annual grasses including Barnyardgrass, goosegrass, crab grass, signal grass and common buffalo grass; Annual broad-leaved weeds including pigweed, goosefoot and purslane

Example applications

Wheat & other small grain cereals; Corn; Soybeans; Maize; Fruit; Vegetables including beans & peas, carrots; Turf & lawns; Potatoes; Vineyards; Peanuts

Efficacy & activity

Availability status

Current

Introduction & key dates

1974, first reported

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

30/11/2028

GB LERAP status

Check label - may vary with formulation

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Netherlands/Spain

Date EC 1107/2009 inclusion expires

30/11/2024

EU Candidate for substitution (CfS)

Yes - two 'Persistent-Bioaccumulative-Toxic' criteria

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

Australia, USA, Morocco

Chemical structure

Isomerism

None

Chemical formula

C₁₃H₁₉N₃O₄

Canonical SMILES

CCC(CC)NC1=C(C=C(C(=C1[N+](=O)[O-])C)C)[N+](=O)[O-]

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

CHIFOSRWCNZCFN-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C13H19N3O4/c1-5-10(6-2)14-12-11(15(17)18)7-8(3)9(4)13(12)16(19)20/h7,10,14H,5-6H2,1-4H3

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
pendimethalin	-

General status

Pesticide type

Herbicide

Substance groups

Dinitroaniline herbicide

Minimum active substance purity

900 g kg⁻¹

Known relevant impurities

EU dossier - 1.2-dichloroethane <= 1 g kg⁻¹; Nitroso-pendimethaline < 0.045 g kg⁻¹

Substance origin

Synthetic

Mode of action

Selective, absorbed by roots and leaves. Inhibition of mitosis and cell division. Microtubule assembly inhibition.

CAS RN

40487-42-1

EC number

254-938-2

CIPAC number

357

US EPA chemical code

108501

PubChem CID

38479

CLP index number

609-042-00-X

Molecular mass

281.31

PIN (Preferred Identification Name)

IUPAC name

N-(1-ethylpropyl)-2,6-dinitro-3,4-xylidine

CAS name

N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine

Other status information

Relevant Environmental Water Quality Standards

UK Environment Agency non-statutory standard for the protection of aquatic life in fresh surface water and salt water: 1.5 µg l⁻¹ as annual average, 6 µg l⁻¹ as max acceptable conc.

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

Alopecurus myosuroides

Physical state

Orange yellow crystalline solid

Formulations

Property

Value

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

AgriGuard
BASF
Greencrop
Headland
Standon
Makhteshim-Agan
BOC Sciences

Example products using this active

Blazer
Bunker
Claymore
PDM 330 EC
PicoMax
Picona
PicoPro, Stomp
PicoStomp
Pendimethalin 330 EC
Trump

Formulation and application details

Often supplied as an emulsifiable or emulsion 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)

0.33

Low

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

49000

n-Hexane

800000

Xylene

800000

Acetone

66100

n-Octanol

Melting point (°C)

Boiling point (°C)

246

Degradation point (°C)

246

Decomposition begins on boiling

Flashpoint (°C)

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

2.51 X 10⁰⁵

Calculated

Log P

5.4

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

1.17

Dissociation constant pKa) at 25 °C

2.8

Strong acid

Vapour pressure at 20 °C (mPa)

3.34

Low volatility. If applied directly to plants or soil, drift is a concern & mitigation is advisable

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

1.27

at 25 °C

Moderately volatile

Volatilisation as max % of applied dose lost

From plant surface

24 hr

Volatilisation is not considered critical for air pollution

From soil surface

24 hr

Volatilisation is not considered critical for air pollution

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

238nm = 28775, 425nm = 5490

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

182.3

Persistent

DT₅₀ (lab at 20 °C)

182.3

Persistent

DT₅₀ (field)

100.6

Persistent

DT₉₀ (lab at 20 °C)

658.6

Very persistent

DT₉₀ (field)

423.2

DT₅₀ modelling endpoint

Note

EU dossier (2016) lab studies DT₅₀ range 97-270 days, DT₉₀ range 331.5-1002 days, Soils=5; Field studies DT₅₀ range 39.8-187 days, Dt90 range 144-582 days, Soils=18

Dissipation rate RL₅₀ (days) on plant matrix

Value

12.0

Note

Kentucky bluegrass thatch, n=1

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

8.0

Note

Published literature RL₅₀ range 5.4-16.0 days, 5 field crops, various matrices, n=7

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Slow

Note

DT₅₀ 7 days in June, 94 days Dec. under environmentally relevant conditions. DT₅₀ 21 days for continuous irradiation.

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

Value

Stable

Note

Stable pH 4 to pH 9

Water-sediment DT₅₀ (days)

Fast

Water phase only DT₅₀ (days)

Moderately fast

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

[Malt: 873 days @ 20-22 DegC, dark conditions; Field study]

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

228

Non-mobile

K_oc (mL g⁻¹)

17491

Notes and range

EU dossier (2016) K_d range 120-677 mL g⁻¹; K_oc range 10241-36604 mL g⁻¹; Soils=9; Other sources Log K_oc 4.13 at 25 °C (R3)

Freundlich

K_f (mL g⁻¹)

220.1

Non-mobile

K_foc (mL g⁻¹)

13792

¹/_n

0.954

Notes and range

EU dossier (2016) K_f range 110.5-510.2 mL g⁻¹; K_foc range 8942-27578 mL g⁻¹; ¹/_n range 0.919-0.980; Soils = 9

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

-0.28

Calculated

Low leachability

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

Value

5.35 X 10^-03

Calculated

Note

Estimated concentrations of chemicals with Koc values greater than 9995 ml g⁻¹ are beyond the scope of the regression data used in SCI-GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI-GROW

Potential for particle bound transport index

High

Calculated

Potential for loss via drain flow

Non-mobile

Calculated

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

4.2

Calculated using the Atkinson method. Assumed 1.5E+06 OH/cm³, 12 hr

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

5100

Whole fish

High potential

CT₅₀ (days)

5.1

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

2-methyl-3,5-dinitro-4-(pentan-3ylamino)benzoic acid (Ref: M455H001)

Minor fraction

0.069

4,5-dimethyl-3-nitro-N-(pentan-3-yl)benzene1,2-diamine (Ref: M455H033)

Major fraction

0.259

Anaerobic

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)

2-methyl-3,5-dinitro-4-(pentan-3ylamino)benzoic acid (Ref: M455H001)

Relevant

4,5-dimethyl-3-nitro-N-(pentan-3-yl)benzene1,2-diamine (Ref: M455H033)

Relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

4,5-dimethyl-3-nitro-N-(pentan-3-yl)benzene1,2-diamine

M455H033

Water

0.259

1-(1-ethylpropyl)-5,6-dimethyl-7-nitro-1H-benzimidazole

M455H029

Water

7-amino-5-methyl-1-(pentan-3-yl)-1H-benzimidazole-6-carboxylic acid

M455H017-1

Animal

7-amino-4-methyl-1-(pentan-3-yl)-1H-benzimidazole-5-carboxylic acid

M455H017-2

Animal

3-((3,4-dimethyl-2,6-dinitrophenyl)amino)pentan-1-ol

M455H019-1

Rat

3-((3,4-dimethyl-2,6-dinitrophenyl)amino)pentan-2-ol

M455H019-2

Rat

(2-methyl-3,5-dinitro-4-(pentan-3-ylamino)phenyl)methanol

M455H025

Rat; Plant

3-hydroxy-6-methyl-2,4-dinitrobenzylhexopyranoside

M455H030

Plant

4-(hydroxymethyl)-3-methyl-2,6-dinitrophenolate

Animal

4-((1-hydroxypentan-3-yl)amino)-2-methyl-3,5-dintrobenzoic acid

M455H047

Animal

4-((1-carboxybutan-2-yl)amino)-2-methyl-3,5-dintrobenzoic acid

M455H050

Animal

2-methyl-3,50dinitro-4-(((2-(sulfooxy)pentan-3-yl)amino)benzoic acid

M455H056

Animal

3-((4-hydroxymethyl)-3-methyl-2,6-dinitrophenyl)amino)pentan-2-ol

M455H066

Animal

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

4665

Mouse

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

(ppm diet)

> 500

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

150

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

1421

Anas platyrhynchos

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

4187 mg kg feed⁻¹

Colinus virginianus

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

17.5

Anas platyrhynchos NOEL

Moderate

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

> 1000

Eisenia foetida

Low

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

33.45

Eisenia foetida

Moderate

Soil micro-organisms

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

Dose: 11.2 kg ha⁻¹

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

193

Folsomia candida

Non-target plants

543

Ryegrass
Seedling emergence, ER₅₀
as g ha⁻¹

402

Tomato
Seedling emergence, 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

Moderate

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

> 101.2

Apis mellifera

Low

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

Chronic as 10-day LC₅₀ µg bee⁻¹ day⁻¹

> 96.5

Apis mellifera

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) as Mortality LR₅₀ g ha⁻¹

> 4000

Chrysoperla carnea

Beneficial insects (Parasitic wasps) as Mortality LR₅₀ g ha⁻¹

1200

Aphidius rhopalosiphi

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

> 4000

Typhlodromus pyri

Beneficial insects (Ground beetles) as Mortality LR₅₀ g ha⁻¹

> 2400

Poecilus cupreus

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

0.196

Oncorhynchus mykiss

Moderate

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

0.006

Pimephales promelas

High

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

11.98

Danio rerio EC₅₀ Embryo

Moderate

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

0.147

Daphnia magna

Moderate

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

0.0145

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)

2.27

Chironomus riparius 48 hr EC₅₀

Moderate

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

0.082

Chironomus riparius 30 day

Moderate

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

227.3

Chironomus riparius

Low

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

0.022

Lemna gibba

Moderate

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

0.004

Selenastrum capricornutum

High

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

0.003

Pseudokirchneriella subcapitata

Moderate

Mesocosm study data

NOEAEC mg l⁻¹

0.0011

Aquatic community

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)

4665

Mouse

Low

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

5000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 6.73

Rat 4 hr (nose only liquid aerosol)

Other Mammal toxicity endpoints

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

0.125

Dog SF=100

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

0.3

Rabbit SF=100

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

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

0.17

Rabbit SF=175

Dermal penetration studies (%)

0.4-33%

concentration & forumalation dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

PPE/PPC recommended

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Non-statutory WHO drinking water guideline 0.02 mg l⁻¹

UK EA QS database 2018

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

Harmful if swallowed
Thyroid & liver toxicant
Bioaccumulates
US EPA - possible human carcinogen

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: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Limited shelf-life

TRANSLATIONS

Language

Name

English

pendimethalin

French

pendimethaline

German

Pendimethalin

Danish

pendimethalin

Italian

pendimetalin

Spanish

pendimetalina

Greek

Polish

pendimetalina

Swedish

pendimetalin

Hungarian

pendimetalin

Dutch

pendimethalin

Norwegian

Record last updated:	25/07/2024
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