Napropamide (Ref: R 7465)

Napropamide (Ref: R 7465)	Last updated: 30/04/2025
(Not known by any other names)

SUMMARY

Napropamide is a widely used herbicide. It has a low mammalian toxicity but is is a known skin and eye irritant. It is moderately soluble in water, and is quite volatile. It is moderately persistent in soil systems and data suggests that under certain conditions it may be persistent in water. It has a low toxicity to birds but is moderately toxic to most aquatic species, honeybees and earthworms.

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: Moderately persistent; GUS: Transition state; Drainflow: Slightly mobile; Potential for particle bound transport: Medium	Ecotoxicity Moderate alert: Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health Moderate alert: Mammals chronic toxicity: Moderate; Reproduction/development effects

GENERAL INFORMATION

Description

A soil applied herbicide for pre-emergence control of weeds in a range of crops including oilseed rape, fruit and woody ornamentals

Example pests controlled

Annual grasses; Broadleaved weeds

Example applications

Vegetables, Fruit tree and bushes; Vines; Tobacco; Olives; Sunflowers; Turf; Oilseed rape; Ornamentals

Efficacy & activity

Availability status

Current

Introduction & key dates

circa 1970, introduced

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

31/12/2031

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

Solvenia/Hungary

Date EC 1107/2009 inclusion expires

31/03/2027

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

Australia

Chemical structure

Isomerism

A chiral molecule. The technical material is a racemate composed of equimolar amounts of (S)- and (R)-napropamide.

Chemical formula

C₁₇H₂₁NO₂

Canonical SMILES

CCN(CC)C(=O)C(C)OC1=CC=CC2=CC=CC=C21

Isomeric SMILES

International Chemical Identifier key (InChIKey)

WXZVAROIGSFCFJ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C17H21NO2/c1-4-18(5-2)17(19)13(3)20-16-12-8-10-14-9-6-7-11-15(14)16/h6-13H,4-5H2,1-3H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance groups

Amide herbicide

Minimum active substance purity

930 g kg⁻¹

Known relevant impurities

EU dossier - toluene <0.14%

Substance origin

Synthetic

Mode of action

Selective, systemic, absorbed through roots and translocated. Acts by preventing root cell elongation and so disrupting growth. Inhibition of very long chain fatty acids (VLCFA, inhibition of cell division)

CAS RN

15299-99-7

EC number

239-333-3

CIPAC number

271

US EPA chemical code

103001

PubChem CID

27189

CLP index number

No data found

Molecular mass

271.36

PIN (Preferred Identification Name)

IUPAC name

(RS)-N,N-diethyl-2-(1-naphthyloxy)propionamide

CAS name

N,N-diethyl-2-(1-naphthalenyloxy)propanamide

Other status information

Potential groundwater contaminant; PAN listed Highly Hazardous Chemical

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

White crystals to light brown solid depending on purity

Related substances & organisms

napropamide-M

Formulations

Property

Value

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

AgriGuard
United Phosphorus
Globalchem
Stauffer

Example products using this active

Devrinol 45F
Jouster
Naprop

Formulation and application details

Usually supplied as a suspension concentrate, emulsifiable concentrate, wettable powder or ganules

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

63.12

Moderate

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

250000

Acetone

10000

n-Heptane

250000

Ethyl acetate

250000

Dichloromethane

Melting point (°C)

74.5

Boiling point (°C)

77.4

Degradation point (°C)

316.7

Flashpoint (°C)

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

1.62 X 10^-01

Calculated

Log P

-0.79

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.18

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

0.167

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

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

7.18 X 10^-03

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

In toluene in methanol: 210nm=146.4
In toluene in HCl: 210nm=146.7
In toluene in NaOH: 210nm=5.388, 290nm=0.344

Surface tension (mN m⁻¹)

59.96

at 20 °C 99.23%

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Not readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

166

Persistent

DT₅₀ (lab at 20 °C)

166

Persistent

DT₅₀ (field)

Moderately persistent

DT₉₀ (lab at 20 °C)

895

Very persistent

DT₉₀ (field)

290

DT₅₀ modelling endpoint

Note

EU 2025 dossier lab studies DT₅₀ (normalised) range 26.8-420 days, DT₉₀ (measured) range 88.9-1790 days, Soils=9; Field studies DT₅₀ (normalised) range 9.03-150 days, DT₉₀ (measured) range 72.4-428 days, Soils=-6; Other sources: 8-12 weeks (R3)

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

1.5

Moderately fast

Note

Mid-European conditions

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

Value

Stable

Note

Stable pH 5 to pH 7, 25 and 40 °C

Water-sediment DT₅₀ (days)

284

Slow

Water phase only DT₅₀ (days)

12.2

Moderately fast

Sediment phase only DT₅₀ (days)

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)

21.5

Slightly mobile

K_oc (mL g⁻¹)

839

Notes and range

EU 2025 dossier K_d range 6.87-47.4 mL g⁻¹, K_oc range 435-1609 mL g⁻¹, Soils=5

Freundlich

K_f (mL g⁻¹)

9.18

Slightly mobile

K_foc (mL g⁻¹)

584

¹/_n

0.88

Notes and range

EU 2025 dossier K_f range 2.0-44.6 mL g⁻¹, K_foc range 320-1590 mL g⁻¹, ¹/_n range 0.72-0.94, Soils=10

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.29

Calculated

Transition state

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

Value

1.20 X 10^-01

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

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

0.552

Calculated using the Atkinson method

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

Low potential

CT₅₀ (days)

Not available

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

alpha-naphthoxy propionic acid

Minor fraction

0.01

Known groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

2,2'-(4,4'-dihydroxy-1,1'-binaphthalene-3,3'-diyl)bis(N,N-diethylpropanamide)

dimer

a=Surface water (photolysis); b=Sediment

a=0.09

2-methylnaphtho[1,2-b]furan-3(2H)-one

MNF

a=Surface water (photolysis); b=Sediment

a=0.15

N,N-diethyl-2-(4-hydroxynaphthalen-1-yl)propanamide

hydroxy napropamide isomer 1

a=Surface water (photolysis); b=Sediment

a=0.20

N-ethylethanamine

diethylamine

a=Surface water (photolysis); b=Sediment

a=0.26

N,N-diethyl-2-(1-hydroxynaphthalen-2-yl)propanamide

hydroxy napropamide isomer 2

a=Surface water (photolysis); b=Sediment

a=0.27

[4-glucuronyl-(N,N-diethyl-2-(1-naphthoxy)) propionamide]

4-OGlu-NPAM

Rat (Urine, Faeces)

N-{[4-(1-carboxyethoxy)naphthalen-1-yl]oxy}glutamic acid

4-OGlu-NOPA

Rat (Urine, Faeces)

naphthalene-1,4-dione

Plant

2-hydroxynaphthalene-1,4-dione

HNQ

Plant

benzene-1,2-dicarboxylic acid

Plant

1-naphthol

Plant

N-({4-[(1-amino-1-oxopropan-2-yl)oxy]naphthalen-1-yl}oxy)glutamic acid

4-OGlu-NOPAM

Rat (Urine, Faeces)

[4-glucuronyl-(N-ethyl-2-(1-naphthoxy)) propionamide]

4-OGlu-DE-NPAM

Rat (Urine, Faeces)

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

High

(ppm diet)

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

> 100

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2250

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 7200 mg kg feed⁻¹

Anas platyrhynchos

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

309

Colinus virginianus NOAEL

Low

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

282.0

Eisenia foetida corr

Moderate

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

16.3

Eisenia foetida

Moderate

Soil micro-organisms

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

Dose: 15.9 mg ha⁻¹ 42 days

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

309

Folsomia candida

Non-target plants

180

Soybean
Vegetative vigour, ER₅₀
as g ha⁻¹

> 8820

Onion Radish
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

Low

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

> 100

Apis mellifera

Low

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

Chronic

Notes

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)

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

> 4500

Aphidius rhopalosiphi

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

> 4500

Typhlodromus pyri

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

13.0

Lepomis macrochirus

Moderate

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

1.1

Salmo gairdneri

Moderate

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

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

14.3

Daphnia magna

Moderate

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

22.4

Daphnia magna

Low

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

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

4.2

Americamysis bahia

Moderate

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 (free-floating, growth) - Acute 7 day EC₅₀, biomass (mg l⁻¹)

0.16

Lemna gibba

Moderate

Aquatic plants (rooted, growth) - Acute 14 day EC₅₀, biomass (mg l⁻¹)

2.03

Myriophyllum spicatum

Moderate

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

4.15

Pseudokirchneriella subcapitata

Moderate

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

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves – Acute EC₅₀ Mortality (mg l⁻¹)

1.4

Crassostrea virginica

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)

> 5000

Rat

Low

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 5.1

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

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

0.3

Rat SF=100

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

1.1

Rat SF=100

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

1.1

Rat SF=100

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

0.3

Rat SF=100

Dermal penetration studies (%)

0.7-13.4

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Risk to bystanders acceptable for proposed uses

Occupational

Risks identified for operators - 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

Rapid and extensive - approx 90% within 72 hrs excreted mainly via urine (35-64%), faeces (39-53%)

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

No data found

General human health issues

Possible spleen, liver and kidney toxicant

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

WHO Classification

U (Unlikely to present an acute hazard)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Stable and non-reactive under normal conditions of use, storage and transport

TRANSLATIONS

Language

Name

English

napropamide

French

napropamide

German

Napropamid

Danish

napropamid

Italian

napropamide

Spanish

napropamida

Greek

Polish

napropamid

Swedish

napropamid

Hungarian

napropamid

Dutch

Norwegian

Record last updated:	30/04/2025
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