Azamethiphos (Ref: GCA 18809)

Azamethiphos (Ref: GCA 18809)	Last updated: 01/09/2023
(Also known as: OMS 1825)

SUMMARY

Azamethiphos is an organophosphate used as an insecticide and as an antiparasitic agent for veterinary use. It is highly soluble in water, volatile and not expected to leach to groundwater. Not a great deal is known about its environmental persistence. It is moderately toxic to mammals and not expected to bioaccumulate. It is a mutagen, neurotoxicant and an acetyl cholinesterase inhibitor. Azamethiphos is highly toxic to birds and aquatic invertebrates and moderately toxic to fish.

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 High alert: Drainflow: Mobile Warning: Significant data are missing	Ecotoxicity High alert: Birds acute ecotoxicity: High; Daphnia acute ecotoxicity: High; Bees acute oral ecotoxicity: High	Human health High alert: Genotoxic; Acetyl cholinesterase inhibitor; Neurotoxicant

GENERAL INFORMATION

Description

Used in fish farming to control external parasites on Atlantic Salmon and for parasite control on other animals

Availability status

Current

Introduction & key dates

1970

Examples of species treated

Salmon; Dogs; cats

Chemical structure

Isomerism

None

Chemical formula

C₉H₁₀ClN₂O₅PS

Canonical SMILES

COP(=O)(OC)SCN1C2=NC=C(C=C2OC1=O)Cl

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

VNKBTWQZTQIWDV-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C9H10ClN2O5PS/c1-15-18(14,16-2)19-5-12-8-7(17-9(12)13)3-6(10)4-11-8/h3-4H,5H2,1-2H3

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Antiparasitic

Substance groups

Organophosphate insecticide; Organothiophosphate insecticide

Minimum active substance purity

>95%

Known relevant impurities

Substance origin

Synthetic

Mode of action

Contact and stomach action, rapid knockdown. Acetylcholinesterase (AChE) inhibitor.

Molecular targets

[Cholinesterase, inhibitor]

CAS RN

35575-96-3

EC number

252-626-0

CIPAC number

None allocated

US EPA chemical code

129101

PubChem CID

71482

CLP index number

No data found

ATCvet Code

QP53AF17

Therapeutic Class

Antiparasitic products, insecticides & repellents: Ecoparasiticides, insecticides & repellents

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: Salmonidae)

Molecular mass

324.68

PIN (Preferred Identification Name)

S-[(6-chloro-2-oxo-1,3-oxazolo[4,5-b]pyridin-3(2H)-yl)methyl] O,O-dimethyl phosphorothioate

IUPAC name

S-6-chloro-2,3-dihydro-2-oxo-1,3-oxazolo[4,5-b]pyridin-3-ylmethyl O,O-dimethyl phosphorothioate

CAS name

S-[(6-chloro-2-oxooxazolo[4,5-b]pyridin-3(2H)-yl)methyl] O,O-dimethyl phosphorothioate

Other status information

PAN Bad Actor Chemical

Relevant Environmental Water Quality Standards

UK non-statutory standard for protection of freshwater and saltwater aquatic life 0.02 µg l⁻¹ as annual average, 0.05 as max acceptable conc.

Physical state

Colourless to grey cystalline solid

Formulations

Property

Product

Manufacturer

Authorisation Route

UK Legal Class

Example products using this active

Salmosan Powder for Suspension for Fish Treatment

Fish Vet Group

UK National authorisation

Prescription only medicine to be authorised by a veterinarian (POM-V)

Formulation and application details

Often supplied as a wettable powders, direct use bait formulations and as bath additives

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

1100

High

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

610000

Dichloromethane

130000

Benzene

100000

Methanol

5800

n-Octanol

Melting point (°C)

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

Flashpoint (°C)

150

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

1.12 X 10⁰¹

Calculated

Log P

1.05

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.6

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

0.0049

Low volatility

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

1.45 X 10^-06

Non-volatile

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

Surface tension (mN m⁻¹)

Refractive Index

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

0.25

Non-persistent

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Best available data, Industry data DT₅₀ in loamy sand circa 6 hours (E3)

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

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

Value

Non-persistent

Note

pH sensitive ranging from 33 days at pH 5 to 4.3 hrs at pH 9

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

Mobile

K_oc

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

-1.57

Calculated

Low leachability

Bio-concentration factor

BCF (l kg⁻¹)

1.56

Estimated

Low potential

CT₅₀ (days)

Not available

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

1180

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

High

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 30.2

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)

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)

10.0

Apis mellifera

Moderate

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

0.1

Apis mellifera

High

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)

> 0.115

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

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

0.00067

Daphnia magna

High

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)

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)

1180

Rat

Moderate

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

2150

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 0.56

Rat

Other Mammal toxicity endpoints

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

0.025

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

List I; List II

Exposure Routes

Public

Occupational

Mammalian dose elimination route and rate

For rats azamethiphos is excreted via faeces, urine & in expelled air. For fish adsorption after topical application is slow and low. Excretion is rapid in all species.

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

Mutagenic potential

Handling issues

Property

Value and interpretation

General

IMDG Transport Hazard Class 6.1

CLP classification 2013

Health: H302, H317, H332
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

UN2783

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

azamethiphos

French

azametiphos

German

Azamethiphos

Danish

azamethiphos

Italian

azametifos

Spanish

azametifos

Greek

Polish

azametifos

Swedish

azametifos

Hungarian

Dutch

azamethifos

Norwegian

Record last updated:	01/09/2023
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