Ethoxyquin

Ethoxyquin	Last updated: 14/09/2023
(Also known as: ethoxyquine; polyethoxyquinoline; PEQ)

SUMMARY

Ethoxyquin is a fungicide used for post-harvest control of scald and other diseases in top fruit. It is moderately soluble in water and miscible with many organic solvents. Ethoxyquin is not volatile. No information is available regarding persistence in soil or water. It is moderately toxic to mammals, fish and aquatic invertebrates. The substance is also moderately toxic to humans and is a recognised irritant. No chronic health impacts have been identified.

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: Drainflow: Slightly mobile Warning: Significant data are missing	Ecotoxicity Moderate alert: Fish acute ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate	Human health Moderate alert: Mammals acute toxicity: Moderate Warning: Significant data are missing

GENERAL INFORMATION

Description

Ethoxyquin is a synthetic chemical preservative used in animal feeds in particular it may be used to retard oxidation and rancidity of feedstuffs, fats, vitamins and carotenoids.

Availability status

Current

Introduction & key dates

circa 1990

Examples of species treated

Poultry, Pigs

Chemical structure

Isomerism

None

Chemical formula

C₁₄H₁₉NO

Canonical SMILES

CCOC1=CC2=C(C=C1)NC(C=C2C)(C)C

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

DECIPOUIJURFOJ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C14H19NO/c1-5-16-11-6-7-13-12(8-11)10(2)9-14(3,4)15-13/h6-9,15H,5H2,1-4H3

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Preservative, Feed additive

Other constituent type

Antioxidant

Substance groups

Quinoline fungicide

Minimum active substance purity

950 g kg⁻¹

Known relevant impurities

EU dossier - p-phenetidine 0.75 g kg⁻¹

Substance origin

Synthetic

Mode of action

Anti-oxidant effecting plant growth

Molecular targets

CAS RN

91-53-2

EC number

202-075-7

CIPAC number

517

US EPA chemical code

055501

PubChem CID

3293

CLP index number

613-014-00-2

ATCvet Code

Not listed

Therapeutic Class

None

Controlled Drug?

Regulation 37/2010 MRL Classification

No data

Molecular mass

217.34

PIN (Preferred Identification Name)

6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline

IUPAC name

1,2-dihydro-2,2,4-trimethylquinolin-6-yl ethyl ether

CAS name

6-ethoxy-1,2-dihydro-2,2,4-trimethylquinoline

Other status information

Chemical subject to PIC regulations; Should not be used on Red Delicious, Golden Delicious or late picked Winesap apples as may reduce quality

Relevant Environmental Water Quality Standards

Physical state

Yellow to brown coloured viscous liquid

Formulations

Property

Product

Manufacturer

Authorisation Route

UK Legal Class

Example products using this active

None identified

No UK authorisation for use with animals

Not applicable

Formulation and application details

Usually formulated as an emulsifiable concentrate

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

60.0

at 25 °C

Moderate

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

Miscible

n-Heptane

Miscible

Methanol

Miscible

Acetone

Miscible

Ethyl acetate

Melting point (°C)

< -20

Boiling point (°C)

150

Degradation point (°C)

150

Flashpoint (°C)

150

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

2.45 X 10⁰³

Calculated

Log P

3.39

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

1.03

Dissociation constant pKa) at 25 °C

4.56

@ 22degC

Vapour pressure at 20 °C (mPa)

0.346

at 25 °C

Low volatility

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

4.43 X 10^-02

at 25 °C

Non-volatile

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

Neutral solution: 350nm = 2450, 228nm = 24300
Acidic solution: 299nm = 1680, 259nm = 6450, 224nm = 24600
Basic solution: 350nm = 2460, 228nm = 250000

Surface tension (mN m⁻¹)

58.5

Refractive Index

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

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

Value

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

Slightly mobile

K_oc

3208

Notes and range

Estimated

Freundlich

K_f

K_foc

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

CT₅₀ (days)

Not available

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

methylethoxyquin

MEQ

Plant

dihydroethoxyquin

DHEQ

Plant

dihydromethylethoxyquin

DHMEQ

Plant

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

1726

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

2417

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 1505 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)

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

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Honeybees (Apis 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)

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

Chronic

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)

Beneficial insects (Predatory mites)

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

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

Daphnia magna

Moderate

Aquatic invertebrates - Chronic 21 day NOEC (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)

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

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

6.1

Pseudokirchneriella subcapitata

Low

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)

1726

Rat

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 1.97

Rat 4 hr (whole body)

Other Mammal toxicity endpoints

Intraperitoneal LD₅₀ = 200 mg kg⁻¹

Mouse

Intravenous LD₅₀ = 178 mg kg⁻¹

Mouse

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

None allocated

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

None allocated

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

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

None allocated

Dermal penetration studies (%)

100

default

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

Mammalian dose elimination route and rate

Rapidly excreted unchanged in urine and faeces of mammals

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

No data found

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

May cause dermatitis, probable sensitiser
Possible liver and kidney toxicant

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising

CLP classification 2013

Health: H302

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

ethoxyquin

French

ethoxyquine

German

Ethoxyquin

Danish

ethoxyquin

Italian

etossichina

Spanish

etoxiquina

Greek

Polish

etoksychina

Swedish

Hungarian

etoxiquin

Dutch

ethoxychin

Norwegian

Record last updated:	14/09/2023
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