Acephate

Acephate	Last updated: 08/08/2021
(Also known as: orthene)

SUMMARY

Acephate is an organophosphate insecticide that is used to control sucking and chewing pests. It is highly soluble in water and most organic solvents, and is volatile. It is not expected to leach to groundwater. Whilst it is mobile, it tends not to be persistence in soil or aquatic systems. It is moderately toxic to mammals and has a low potential for bioaccumulation. Acephate is also a recognised irritant. It is has a moderate to low toxicity to birds, honeybees, earthworms and most aquatic organisms.

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: Moderately mobile	Ecotoxicity High alert: Bees acute oral ecotoxicity: High	Human health High alert: Endocrine distrupter; Acetyl cholinesterase inhibitor; Neurotoxicant

GENERAL INFORMATION

Description

An organophosphate insecticide used normally as a foliar spray to control chewing and sucking insects

Example pests controlled

Aphids; Leaf miners; Lepidopterous larvae; Sawflies; Thrips, Ants

Example applications

Fruit; Vegetables; Potatoes; Sugarbeet; Vines; Rice; Hops; Ornamentals; Greenhouse crops including peppers, cucumbers

Efficacy & activity

Availability status

Current

Introduction & key dates

circa 1970

UK regulatory status

UK COPR regulatory status

Not approved

Date COPR inclusion expires

Expired

UK LERAP status

No UK approval for use

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Italy

Date EC 1107/2009 inclusion expires

Expired

EU Candidate for substitution (CfS)

Not applicable

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

Additional information

Also used in

Australia, USA

Chemical structure

Isomerism

Chiral, existing in the S- and R-forms

Chemical formula

C₄H₁₀NO₃PS

Canonical SMILES

CC(=O)NP(=O)(OC)SC

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

YASYVMFAVPKPKE-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C4H10NO3PS/c1-4(6)5-9(7,8-2)10-3/h1-3H3,(H,5,6,7)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
acephate	-

General status

Pesticide type

Insecticide

Substance group

Organophosphate

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Broad-spectrum, contact and ingestion systemic action. Weak acetylcholinesterase (AChE) inhibitor.

CAS RN

30560-19-1

EC number

250-241-2

CIPAC number

338

US EPA chemical code

103301

PubChem CID

1982

Molecular mass

183.17

PIN (Preferred Identification Name)

(E)-(O,S-dimethyl acetylphosphoramidothioate)

IUPAC name

(RS)-N-[methoxy(methylthio)phosphinoyl]acetamide

CAS name

O,S-dimethyl acetylphosphoramidothioate

Other status information

Potential groundwater contaminant; Chemical subject to PIC regulations

Relevant Environmental Water Quality Standards

Herbicide Resistance Classification (HRAC)

Not applicable

Herbicide Resistance Classification (WSSA)

Not applicable

Insecticide Resistance Classification (IRAC)

Fungicide Resistance Classification (FRAC)

Not applicable

Examples of recorded resistance

Adoxophyes orana,Aphis gossypii, Myzus persicae, Phorodon humuli, Trialeurodes vaporariorum, Lygus lineolaris, plus others

Physical state

Colourless/white solid

Related substances & organisms

chlorpyrifos

imidacloprid

Formulations

Property

Value

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

Cheminova
King Tech Corp
United Phorsporus
Valent
Chevron

Example products using this active

Tornado
Ortril
Cekucefate
Sunphate
Orthene
Ortran
Acephate
Acephate 50 Fire Ant Insecticide

Formulation and application details

Usually supplied as a soluble powder or granules.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

790000

High

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

151000

Acetone

100000

Ethanol

35000

Ethyl acetate

100

Hexane

Melting point (°C)

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

Flashpoint (°C)

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

1.41 X 10^-01

Calculated

Log P

-0.85

Low

Bulk density (g ml⁻¹)

1.35

Dissociation constant pKa) at 25 °C

8.35

Weak acid

Vapour pressure at 20 °C (mPa)

0.226

Low volatility

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

5.15 X 10^-08

Non-volatile

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)

Non-persistent

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Best available data

Dissipation rate RL₅₀ on plant matrix

Value

4.8

Note

Published literature RL₅₀ range 0.7-8.5 days, 8 field & undercover grown crops, various matrices, n=11

Dissipation rate RL₅₀ on and in plant matrix

Value

5.8

Note

Published literature RL₅₀ range 1.0-12.4 days, 12 field & undercover grown crops, various matrices, n=19

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Moderately fast

Note

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

Value

Moderately persistent

Note

Hydrolysis data applies for pH range 5-7

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

1.6

Moderately mobile

K_oc

302

Notes and range

Literature data: K_d range 0.54-4.98 mL g⁻¹, K_oc range 24.4-545 mL g⁻¹, Soils = 19

Freundlich

K_f

0.21

Mobile

K_foc

40.3

¹/_n

1.81

Notes and range

Literature data: K_f range 0.01-0.90 mL g⁻¹, K_foc range 1.9-188 mL g⁻¹, 1.n range 1.43-2.08, Soils = 19

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.14

Calculated

Low leachability

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

Value

2.54 X 10^-03

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

methamidophos (Ref: ENT 27396)

Soil

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

0.03

Low potential

CT₅₀ (days)

Not available

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

945

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

0.25

Rat

High

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

350

Anas platyrhynchos

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

110

Oncorhynchus mykiss

Low

Fish - Chronic 21 day NOEC (mg l⁻¹)

4.7

Galaxias maculatus 20 day

Moderate

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

67.2

Daphnia magna

Moderate

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

Daphnia magna

Low

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

7.3

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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)

Non-target plants

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

980

Unknown species

Low

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

Honeybees (Apis spp.)

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

1.78

Apis mellifera

Moderate

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

> 0.23

Apis mellifera

High

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

Bumblebees (Bombus spp.)

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

3.99

Bombus terrestris 72 hr

Moderate

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

7.37

Bombus terrestris 72 hr

Moderate

Literature LD₅₀ varies 3.93-135.5 µg bee⁻¹ depending on test duration 24-72 hrs

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 pollinators (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other pollinators (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

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

> 22974

Low

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

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Other arthropod (1)

LR₅₀ g ha⁻¹

% Effect

Harmful

Parasitoids

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

Soil micro-organisms

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)

945

Rat

Moderate

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

10000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

15.0

Rat

Other Mammal toxicity endpoints

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

0.03

JMPR 2005

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

0.1

JMPR 2005

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

Dermal route highest risk
Minimal risk of dietary exposure
Small risk of exposure in food and water from metabolite methamidophos
Source: US EPA

Occupational

Possible exposure via inhalation and dermal contact
Source: US EPA

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

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

USEPA - possible human carcinogen
Endocrine issues - Disruption of hormone expression in the hypothalamus

Handling issues

Property

Value and interpretation

General

IMDG Transport Code is 6.1

CLP classification 2013

Health: H302

EC Risk Classification

Xn - Harmful: R22

EC Safety Classification

S2, S36

WHO Classification

II (Moderately hazardous)

UN Number

Active 2783, liquid products usually 3018

Waste disposal & packaging

TRANSLATIONS

Language

Name

English

acephate

French

acéphate

German

Acephat

Danish

acephat

Italian

acefate

Spanish

acefato

Greek

Polish

acefat

Swedish

Hungarian

acefat

Dutch

Record last updated:	08/08/2021
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