Fenthion (Ref: OMS 2)

Fenthion (Ref: OMS 2)	Last updated: 23/08/2024
(Also known as: MPP; ENT 25540; Bayer 29493; S-1752; BAY 29493; DMTP)

SUMMARY

Fenthion is an insecticide for sucking and chewing pests. It has a low water solubility but is generally highly soluble in organic solvents. It is volatile and is not expected to leach to groundwater. Its persistence in soil and water systems depends on local conditions. It is moderately toxic to mammals and a cholinesterase inhibitor. Fenthion is highly toxic to birds and honeybees and has a high to moderate toxicity to most aquatic species and earthworms.

GENERAL INFORMATION

Description

A organophosphate insecticide used in veterinary medicine for external parasite control

Availability status

Current

Introduction & key dates

1960, first reported & introduced

Examples of veterinary uses

Used to to control lice, fleas, ticks, flies and other external parasites

Examples of species treated

Cattle; Pigs; Dogs

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

None

Chemical formula

C₁₀H₁₅O₃PS₂

Canonical SMILES

CC1=C(C=CC(=C1)OP(=S)(OC)OC)SC

Isomeric SMILES

International Chemical Identifier key (InChIKey)

PNVJTZOFSHSLTO-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C10H15O3PS2/c1-8-7-9(5-6-10(8)16-4)13-14(15,11-2)12-3/h5-7H,1-4H3

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Insecticide, Antiparasitic

Substance groups

Organophosphate insecticide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Contact, stomach and respiratory action. Acetylcholinesterase (AchE) inhibitor.

Molecular targets

[Cholinesterase, Inhibitor]

CAS RN

55-38-9

EC number

200-231-9

CIPAC number

US EPA chemical code

053301

PubChem CID

3346

CLP index number

015-048-00-8

Therapeutic Class

Antiparasitic products, insecticides & repellents: Ectoparasiticides

ATCvet Code

QP53BB02

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

278.33

PIN (Preferred Identification Name)

O,O-dimethyl O-[3-methyl-4-(methylsulfanyl)phenyl] phosphorothioate

IUPAC name

O,O-dimethyl O-4-methylthio-m-tolyl phosphorothioate

CAS name

O,O-dimethyl O-(3-methyl-4-(methylthio)phenyl) phosphorothioate

Other status information

Severe Marine Pollutant; Evidence of use in third world countries; Chemical subject to PIC regulations; Highly toxic to birds

Relevant Environmental Water Quality Standards

Physical state

Colourless oily liquid

Related substances & organisms

fenthion-ethyl

fenthion sulfone

fenthion sulfoxide

Formulations

Property

Product

Manufacturer

Authorisation Route

Legal Class (GB/UK)

Example products (past and present) using this active

Formulation and application details

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

4.2

Low

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

100000

Hexane

250000

Toluene

250000

Dichloromethane

250000

Isopropanol

Melting point (°C)

7.5

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

170

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

6.92 X 10⁰⁴

Calculated

Log P

4.84

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

1.25

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

0.37

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)

2.40 X 10^-02

Non-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)

Refractive Index

Environmental release

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

Non-persistent

DT₅₀ (lab at 20 °C)

Moderately persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Data variable DT₅₀ ranges 1(aerobic) - 34 days

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

0.4

Fast

Note

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

Value

Stable

Note

Water-sediment DT₅₀ (days)

Moderately fast

Water 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)

Slightly mobile

K_oc (mL g⁻¹)

1500

Notes and range

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.26

Calculated

Low leachability

Bio-concentration factor

BCF (l kg⁻¹)

154

Whole body (Other literature Log BCF range 1.0-2.3 ())

Threshold for concern

CT₅₀ (days)

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

fenthion sulfone

fenthion sulfoxide (Ref: BAY S 2281)

Known groundwater metabolites

None

Other known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

586

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat 2 yr

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

7.2

Colinus virginianus

High

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

375

Eisenia foetida

Moderate

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

Soil micro-organisms

Nitrogen mineralisation: >25% effect
Carbon mineralisation: No significant adverse effect

Dose: 10 uL/kg soil 20 °C

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)

> 0.308

Apis mellifera

High

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)

0.8

Oncorhynchus mykiss

Moderate

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

0.12

Pimephales promelas 30 day

Moderate

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

4.25

Danio rerio EC₅₀ Embryo

Moderate

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

0.0057

Daphnia magna

High

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

0.000013

Daphnia magna

High

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

0.0015

Ceriodaphnia dubia

High

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

0.00018

Americamysis bahia

High

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

0.0078

Chironomus salinarius 24 hr

High

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)

1.79

Scenedesmus subspicatus

Moderate

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

> 0.3

Pseudokirchneriella subcapitata 48 hr

Moderate

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)

586

Rat

Moderate

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

1680

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

1.2

Rat

Other Mammal toxicity endpoints

Intraperitoneal LD₅₀ = 260 mg kg⁻¹

Rat

Intravenous LD₅₀ = 320 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)

0.01

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 (%)

Dangerous Substances Directive 76/464

List I; List II

Exposure Routes

Public

Occupational

Ingestion main poisoning route

Mammalian dose elimination route and rate

Excreted in the faeces and urine almost completely after 3days

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

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Harmful in contact with skin or if inhaled or swallowed
May harm central nervous, cardiovascular, and respiratory systems
Suspected of causing genetic defects

Handling issues

Property

Value and interpretation

General

IMDG Transport Hazard Class 6.1

CLP classification 2013

Health: H302, H312, H331, H341
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

UN3018

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

fenthion

French

fenthion

German

Fenthion

Danish

fenthion

Italian

fention

Spanish

fention

Greek

fenthion

Polish

fention

Swedish

Hungarian

fention

Dutch

fenthion

Norwegian

Record last updated:	23/08/2024
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