Pethoxamid (Ref: ASU 96 520H)

Pethoxamid (Ref: ASU 96 520H)	Last updated: 26/02/2021
(Also known as: pethoxamide; TKC 94)

GENERAL INFORMATION

Description

A pre-emergence and early post-emergence herbicide to control some grass and broad-leaved weeds

Example pests controlled

Foxtail; Crabgrass; Barnyardgass; Ladysthumb; Bindweed; Pigweed; Common lambsquarter

Example applications

Corn; Winter OSR; Soybeans; Peas and beans; Tobacco

Efficacy & activity

Substances has been evaulated via field trials and has been in usefor many years

Availability status

Current

Introduction & key dates

2002

UK regulatory status

UK COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

UK LERAP status

Not applicable

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Austria/Czech Republic

Date EC 1107/2009 inclusion expires

30/11/2033

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

Chemical structure

Isomerism

Chemical formula

C₁₆H₂₂ClNO₂

Canonical SMILES

CCOCCN(C(=O)CCl)C(=C(C)C)C1=CC=CC=C1

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

CSWIKHNSBZVWNQ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C16H22ClNO2/c1-4-20-11-10-18(15(19)12-17)16(13(2)3)14-8-6-5-7-9-14/h5-9H,4,10-12H2,1-3H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance group

Chloroacetamide

Minimum active substance purity

945 g kg⁻¹

Known relevant impurities

EU dossier - Toluene <3.0 g kg⁻¹

Substance origin

Synthetic

Mode of action

Systemic, absorbed by roots and young shoots. Inhibition of VLCFA (inhibition of cell division).

CAS RN

106700-29-2

EC number

CIPAC number

665

US EPA chemical code

PubChem CID

6450826

Molecular mass

295.81

PIN (Preferred Identification Name)

2-chloro-N-(2-ethoxyethyl)-N-(2-methyl-1-phenylprop-1-en-1-yl)acetamide

IUPAC name

2-chloro-N-(2-ethoxyethyl)-N-(2-methyl-1-phenylprop-1-enyl)acetamide

CAS name

2-chloro-N-(2-ethoxyethyl)-N-(2-methyl-1-phenyl-1-propenyl)acetamide

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

Off-white crystalline solid

Formulations

Property

Value

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

Successor

Example products using this active

Formulation and application details

Usually formulated as an emulsifiable concentrate for use as a foliar spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

400

Moderate

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

117000

n-Heptane

250000

n-Hexane

250000

Methanol

250000

Ethyl acetate

Melting point (°C)

37.5

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

200

Flashpoint (°C)

299

Auto-flammability

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

9.12 X 10⁰²

Calculated

Log P

2.96

at pH 5

Moderate

Bulk density (g ml⁻¹)

1.19

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

2.8

Low volatility

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

1.18 X 10^-03

Non-volatile

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

Acidic: 242nm=12100, Neutral: 243nm=12200, Basic: 243nm=12200

Surface tension (mN m⁻¹)

53.0

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Not readily biodegradeable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

6.3

Non-persistent

DT₅₀ (lab at 20 °C)

6.3

Non-persistent

DT₅₀ (field)

14.8

Non-persistent

DT₉₀ (lab at 20 °C)

20.9

Non-persistent

DT₉₀ (field)

84.9

DT₅₀ modelling endpoint

Note

EU 2016 RAR dossier lab studies DT₅₀ range 5.5-8.1 days, DT₉₀ range 18.2-27.0 days, Soils=4; Field studies range 7.3-22.2 days, DT₉₀ range 73.7-96.0 days, Soils=2

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

Slow

Note

DT₅₀ 49 days, natural sunlight, 40 deg N, 12 hrs daylight.

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

Value

Stable

Note

Stable pH 4 to pH 9

Water-sediment DT₅₀ (days)

9.5

Fast

Water phase only DT₅₀ (days)

8.0

Moderately fast

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

Worse case field value

K_oc

Notes and range

22.2

Freundlich

K_f

4.4

Moderately mobile

K_foc

211

¹/_n

0.89

Notes and range

EU 2016 RAR dossier K_f range 1.12-9.15 mL g⁻¹, K_foc range 187-241 mL g⁻¹, No ¹/_n range 0.87-0.91, Soils=4

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.96

Calculated

Transition state

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

Value

5.21 X 10^-02

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

N-(2-ethoxyethyl)-N-(2-methyl-1-phenyl-1-propenyl)-2-sulfoacetamide

Soil

0.112

Major fraction, Relevant

N-(2-ethoxyethyl)-N-((1Z)-3-hydroxy-2-methyl-1-phenylprop-1-en-1-yl)-2-sulfanylacetamide

Soil

0.009

Minor fraction, relevant

2-(N-(2-Methyl-1-phenylprop-1-en-1-yl)-2-sulfoacetamido)acetic acid

Soil

0.009

Minor fraction, relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

3-[N-(2-ethoxyethyl)-N-(2-methyl-1-phenyl-1-propenyl)-carbamoylmethylthio]-D,L-lactic acid

pethoxamid metabolite MET-41; TKC-94-S-lactic acid

Plant

3-[N-(2-ethoxyethyl)-N-(2-methyl-1-phenyl-1-propenyl)-carbamoylmethylsulfinyl]-D,L lactic acid

pethoxamid metabolite MET-50; TKC-94-SO-lactic acid

Plant

3-N-(2-ethoxyethyl)-N-(2-methyl-1-phenyl-1-propenyl)-carbamoyl-methylthio]-2-(1-alpha-D-glucopyranosyloxy)propionic acid

pethoxamid metabolite MET-58; TKC-94-S-lactic glucoside

Plant

S-[N-(2-ethoxyethyl)-N-(2-methyl-1-phenyl-1-propenyl)-carbamoyl-methyl]-D,L-cystein

pethoxamid metabolite MET-30; TKC-94 cystein

Plant

N-(2-amino-4-carboxybutanoic-4-yl)-S-[N-(2-ethoxyethyl)-N-(2-methyl-1-phenyl-1-propenyl)-carbamoyl-methyl]-D,L-cystein

TKC-94-g-glutamyl cystein

Plant

N-(2-ethoxyethyl)-N-(2-methyl-1-phenyl-1-propenyl)-2-(2-aminopropion-3-yl)sulfinylacetamide

pethoxamid metabolite MET-49; TKC-94-SO-cystein

Plant

N-(2-carboxyacetyl)-S-[N-(2-ethoxyethyl)-N-(2-methyl-1-phenyl-1-propenyl)carbamoyl-methyl]-D,L-cystein

pethoxamid metabolite MET-47; TKC-94-N-malonyl cystein

Plant

N-(2-ethoxyethyl)-2-sulfinyl-N-(2-methyl-1-phenyl-1-propenyl)-acetamide

TKC-94-thiol

Plant

N-(2-ethoxyethyl)-2-mercapto-N-(2-methyl-1-phenyl-1-propenyl)-acetamide

pethoxamid metabolite MET-43; TKC-94-thiol

Plant

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

983

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat 2 year

High

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

1578

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

1200 mg kg bw⁻¹ day⁻¹

Colinus virginianus

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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

2.2

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

1.1

Oncorhynchus mykiss 28 day

Moderate

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

Daphnia magna

Moderate

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

2.8

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)

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

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

0.0247

Lemna gibba

Moderate

Non-target plants

0.425

Lolium perenne
Vegetative vigour, ER₅₀
As g product ha⁻¹

0.592

Lolium perenne
Seedling emergence, ER₅₀
As g product ha⁻¹

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

> 149

Pseudokirchneriella subcapitata

Low

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)

> 200

Apis mellifera

Low

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

> 200

Apis mellifera

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)

> 200

Bombus terrestris

Low

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

> 201

Bombus terrestris

Low

Mason bees (Osmia spp.)

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

> 200

Osmia bicornis

Low

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)

316

Eisenia foetida

Moderate

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

8.0

Eisenia foetida

Moderate

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Other arthropod (1)

LR₅₀ g ha⁻¹

% Effect

100

Mortality [Dose: 1.2 kg/ka]
Aphidius rhopalosiphi imagine

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

100

Mortality [Dose: 1.2 kg ha⁻¹]
Typhlodromus pyri protonymph

Soil micro-organisms

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

Dose: 12 kg ha⁻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)

983

Rat

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 4.16

Rat 4 hr (whole body)

Other Mammal toxicity endpoints

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

0.01

Rat SF=100

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

0.08

Rat SF=100

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

0.08

Rat SF=100

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

0.02

Dog 1 year SF=100

Dermal penetration studies (%)

2-8

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Minimal risk from dietary exposure
Risk assessment indicates ARfD would not normally be execeeded

Occupational

Risk of operator exposure where protective equipment is not used - PPE/PPC advised

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

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

General human health issues

Possible liver & thyroid toxicant

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
Auto-flammability @ 299 DegC

CLP classification 2013

Health: H302, H317
Environment: H400, H410

EC Risk Classification

Xn - Harmful: R22, R43
N - Dangerous for the environment: R50, R53

EC Safety Classification

S2, S24, S37, S46, S60, S61

WHO Classification

NL (Not listed)

UN Number

Waste disposal & packaging

TRANSLATIONS

Language

Name

English

pethoxamid

French

German

Pethoxamid

Danish

pethoxamid

Italian

Spanish

Greek

Polish

petoksamid

Swedish

Hungarian

Dutch

Record last updated:	26/02/2021
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