Pendimethalin (Ref: AC 92553)

Pendimethalin (Ref: AC 92553)	Last updated: 21/10/2020
(Also known as: pendimethaline; penoxalin; phenoxalin)

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

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/08/2024

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

Netherlands/Spain

Date EC 1107/2009 inclusion expires

31/08/2024

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
✓	✓	✓	✓	✓	✓		✓	✓

Also used in

Australia, USA

Chemical structure

Isomerism

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 group

Dinitroaniline

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

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 Classification (HRAC)

Herbicide Resistance Classification (WSSA)

Insecticide Resistance Classification (IRAC)

Not applicable

Fungicide Resistance Classification (FRAC)

Not applicable

Examples of recorded resistance

Alopecurus myosuroides

Physical state

Orange yellow crystalline solid

Related substances & organisms

solvent naphtha

flufenacet

imazamox

picolinafen

trifluralin

isoproturon

Formulations

Property

Value

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

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

Example products using this active

AgriGuard
BASF
Greencrop
Headland
Standon
Makhteshim-Agan

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)

Not expected to self ignite; Not highly flammable

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

2.51 X 10⁰⁵

Calculated

Log P

5.4

High

Bulk 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

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

1.27

at 25 °C

Moderately volatile

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 on plant matrix

Value

12.0

Note

Kentucky bluegrass thatch, n=1

Dissipation rate RL₅₀ 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

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

228

Non-mobile

K_oc

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

220.1

Non-mobile

K_foc

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

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

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

Soil

0.069

Minor fraction; Relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

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

M455H033

Soil (anaerobic); 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

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

5100

Whole fish

High potential

CT₅₀ (days)

5.1

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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

0.196

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

0.006

Pimephales promelas

High

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

0.147

Daphnia magna

Moderate

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

0.0145

Daphnia magna

Moderate

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)

0.082

Chironomus riparius 30 day

Moderate

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

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

0.022

Lemna gibba

Moderate

Non-target plants

543

Ryegrass
Seedling emergence, ER₅₀
as g ha⁻¹

402

Tomato
Seedling emergence, ER₅₀
as g ha⁻¹

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

Honeybees (Apis spp.)

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

100

Apis meliifera

Moderate

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

> 101.2

Apis meliifera

Low

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)

> 1000

Eisenia foetida

Low

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

33.45

Eisenia foetida

Moderate

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

193

Folsomia candida

Other arthropod (1)

LR₅₀ g ha⁻¹

1200

=
Typhlodromus pyri

% Effect

100

Mortality [Dose: 3.2 kg ha⁻¹]
Aphidius rhopalosiphi adult

Other arthropod (2)

LR₅₀ g ha⁻¹

4000

>
Aphidius rhopalosiphi

% Effect

Mortality [Dose: 3.2 kg ha⁻¹]
Typhlodromus pyri protonymph

Soil micro-organisms

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

Dose: 11.2 kg ha⁻¹

Mesocosm study data

NOEAEC mg l⁻¹

0.0011

Aquatic community

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)

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

European MRLs

EU MRL pesticide database

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)

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
USEPA - possible human carcinogen

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Code is variable depending upon product, often either 3 or 9

CLP classification 2013

Health: H317
Environment: H400, H410

EC Risk Classification

Xn - Harmful: R43
N - Dangerous for the environment: R50, R53

EC Safety Classification

S2, S22, S29, S37, S60, S61

WHO Classification

II (Moderately hazardous)

UN Number

Variable with product, usually 1993 or 3082

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

Language

Name

English

pendimethalin

French

pendimethaline

German

Pendimethalin

Danish

pendimethalin

Italian

pendimetalin

Spanish

pendimetalina

Greek

Polish

pendimetalina

Swedish

pendimetalin

Hungarian

pendimetalin

Dutch

pendimethalin

Record last updated:	21/10/2020
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