Pethoxamid (Ref: ASU 96 520H)

Pethoxamid (Ref: ASU 96 520H)	Last updated: 24/07/2024
(Also known as: pethoxamide; TKC 94)

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 Moderate alert: GUS: Transition state; Drainflow: Moderately mobile	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health Moderate alert: Mammals acute toxicity: Moderate; Reproduction/development effects

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, introduced

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

30/11/2033

UK LERAP status

No data

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
			✓	✓	✓		✓	✓

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

C₁₆H₂₂ClNO₂

Canonical SMILES

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

Isomeric SMILES

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 groups

Chloroacetamide herbicide; Amide herbicide

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 very long chain fatty acids (VLCFA, inhibition of cell division)

CAS RN

106700-29-2

EC number

600-765-6

CIPAC number

665

US EPA chemical code

PubChem CID

6450826

CLP index number

616-145-00-3

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 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

Off-white crystalline solid

Formulations

Property

Value

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

Example products using this active

Successor

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

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data - obsrrvations from metabolism studies demonstrate residues do not accumilate in fat

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. 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)

1.18 X 10^-03

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

2.3

24 hr

Volatilisation is not considered critical for air pollution

From soil surface

1.4

24 hr

Volatilisation is not considered critical for air pollution

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 (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

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

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)

Worse case field value

K_oc (mL g⁻¹)

Notes and range

22.2

Freundlich

K_f (mL g⁻¹)

4.4

Moderately mobile

K_foc (mL g⁻¹)

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

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

1.2

Calculated using the Atkinson method. Assumed 1.6E+05 OH/cm³, 12 hr

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

No data

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

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

Major fraction

0.112

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

Minor fraction

0.09

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

Minor fraction

0.09

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

Minor fraction

0.088

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)

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

Relevant

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

Relevant

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

Relevant

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

Relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

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-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

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

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

983

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat 2 yr

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)

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

316

Eisenia foetida

Moderate

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

0.8

Eisenia foetida corr

Moderate

Soil micro-organisms

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

Dose: 12 kg ha⁻¹

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

35.6

Folsomia candida corr

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

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)

Chronic as 10-day LDD₅₀ µg bee⁻¹ day⁻¹

31.6

Apis mellifera

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 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

> 1204

Chrysoperla carnea

Beneficial insects (Parasitic wasps) as % Mortality at 1.2 kg ha⁻¹

100

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as % Mortality at 1.2 kg ha⁻¹

100

Typhlodromus pyri Protonymph

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

> 1204

Poecilus cupreus

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

2.2

Oncorhynchus mykiss

Moderate

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

1.1

Oncorhynchus mykiss 28 day

Moderate

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

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

Daphnia magna

Moderate

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

2.8

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)

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

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

> 149

Pseudokirchneriella subcapitata

Low

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

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Mammalian dose elimination route and rate

Extensively metabolised. >90% excreted within 96 hrs - approx 60% via faeces & 35% via urine

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

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

pethoxamid

French

German

Pethoxamid

Danish

pethoxamid

Italian

Spanish

Greek

Polish

petoksamid

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	24/07/2024
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