Naphthalene

Naphthalene	Last updated: 29/08/2024
(Also known as: tar camphor; naphthaline; moth balls)

SUMMARY

Naphthalene is only used for non-food applications. Slightly toxic if ingested but more serious effects may be seen if inhaled. It is considered a skin and eye irritant. It is also thought to be carcinogenic. Little is known about its environmental fate mainly because its usage patterns would minimise its release. Data suggests that it would be rapidly lost from the soil by evaporation, volatilization, and biodegradation. Non-toxic to birds and earthworms. It is moderately toxic to aquatic species but exposure is unlikely. No data for the risk posed to honeybees has 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: GUS: Transition state; Drainflow: Slightly mobile; Potential for particle bound transport: Medium Warning: Significant data are missing	Ecotoxicity Moderate alert: Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate	Human health High alert: Neurotoxicant

GENERAL INFORMATION

Description

A largely obsolete insecticide once used as a moth repellant for the protection of textiles and as an animal repellant against nuisance vertebrate pests. It is also a constituent of some inert product additives.

Example pests controlled

Moths

Example applications

Non-cropped situations; Wool clothing and textiles

Efficacy & activity

Appearance and life cycle

Availability status

Considered obsolete but may be available in some countries

Introduction & key dates

1948, first registered as a pestcide USA

Taxonomic classification

GB regulatory status

GB COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

GB LERAP status

No UK approval for use as a pesticide

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Not applicable

Date EC 1107/2009 inclusion expires

Not applicable

EU Candidate for substitution (CfS)

Not applicable

Listed in EU database

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

Known to be also used in the following countries

Chemical structure

Isomerism

None

Chemical formula

C₁₀H₈

Canonical SMILES

C1=CC=C2C=CC=CC2=C1

Isomeric SMILES

International Chemical Identifier key (InChIKey)

UFWIBTONFRDIAS-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C10H8/c1-2-6-10-8-4-3-7-9(10)5-1/h1-8H

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
naphthalene	-

General status

Biopesticide type

Semiochemical, Other substance

Other bioactivity & uses

Constituent of some solvents

Substance groups

Fumigant pesticide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Repellent action caused by strong odour, DNA damage response

Substance source

Substance production

Uses

Target pests

Target host

Farming system suitability

CAS RN

91-20-3

EC number

202-049-5

CIPAC number

613-139-00-2

US EPA chemical code

055801

PubChem CID

931

CLP index number

613-139-00-2

Molecular mass

128.17

PIN (Preferred Identification Name)

naphthalene

IUPAC name

naphthalene

CAS name

naphthalene

Other status information

Prohibited in Europe since 2008; WFD priority substance

Relevant Environmental Water Quality Standards

EU Directive 2008/105/EC EQS Inland surface waters: 2.4 µg l⁻¹; other surface waters 1.2 µg l⁻¹ as annual average

Herbicide Resistance Class (HRAC MoA class)

Not applicable

Herbicide Resistance Class (WSSA MoA class)

Not applicable

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

White crystalline flaky solid

Related substances & organisms

1-methylnaphthalene

2-methylnaphthalene

Formulations

Property

Product

Manufacturer

Example products

Formulation and application details

Was usually supplied as pellets, granules or flakes and applied by hand

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

31.0

at 25 °C

Low

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

285000

Benzene

77000

Methanol

500000

Chloroform

Melting point (°C)

81.2

Boiling point (°C)

218

Degradation point (°C)

Flashpoint (°C)

(closed cup)

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

1.95 X 10⁰³

Calculated

Log P

3.29

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.14

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

6500

Highly volatile. 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)

2.78 X 10⁰¹

Moderately volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

Moderately persistent

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Literature data reports DT₅₀'s of around 80 days unless the soil is contaminated with polycyclic aromatic hydrocarbons which will facilitate much quicker degradation rates.

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

Stable

Note

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

Value

Stable

Note

Water-sediment DT₅₀ (days)

Stable

Water phase only DT₅₀ (days)

Stable

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)

Slightly mobile

K_oc (mL g⁻¹)

750

Notes and range

Literature states K_oc values range 200-1470 ml/g

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

cis-1,2-dihydroxy-1,2-dihydronaphthalene

1,2-dihydroxy-naphthalene

2-hydroxchromene-2-carboxylate

HCCA

trans-o-hydroxy-benzylidenpyruvate

tHBPA

salicyladehyde

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 2200

Rat

Low

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)

> 5620

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

> 2730

Eisenia foetida

Low

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

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

> 0.11

Oncorhynchus mykiss

Moderate

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

> 0.67

Oncorhynchus kisutch 40 day

Moderate

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

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

> 15.0

Daphnia magna

Moderate

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

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)

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

> 25.0

Pseudokirchneriella subcapitata

Low

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

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves – Acute EC₅₀ development (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)

> 2200

Rat

Low

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

2500

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 0.34

Rat 1 hr

Other Mammal toxicity endpoints

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

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

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

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

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

Exposure may occur via inhalation, skin absorption, ingestion, skin and/or eye contact

Mammalian dose elimination route and rate

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

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

Blood toxicant at high doses
Liver toxicant
May cause hemolytic anemia
IARC Group 2B carcinogen; CLP data - suspected carcinogen; US NTP - suspected carcinogen; OSHA - Anticipated human carcinogen

Handling issues

Property

Value and interpretation

General

Flammable

CLP classification 2013

Health: H302, H351
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

naphthalene

French

naphtalene

German

Danish

Italian

Spanish

Greek

Polish

naftalen

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	29/08/2024
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