MCPA-thioethyl

MCPA-thioethyl	Last updated: 12/01/2021
(Also known as: phenolthiol)

GENERAL INFORMATION

Description

A herbicide for control of annual and perennial broad-leaved weeds.

Example pests controlled

Annual and perennial broad-leaved weeds including Charlock, Wild radish, Dandylion, Capeweed, Fat hen and Hedge mustards

Example applications

Wheat; Oats; Tritical; Rye; Establish gras

Efficacy & activity

Availability status

Current

Introduction & key dates

1973

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/10/2024

UK LERAP status

None

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Poland/Netherlands

Date EC 1107/2009 inclusion expires

31/10/2021

EU Candidate for substitution (CfS)

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
✓	✓	✓	✓	✓	✓	✓	✓	✓

Also used in

Chemical structure

Isomerism

Chemical formula

C₁₁H₁₃ClO₂S

Canonical SMILES

CCSC(=O)COC1=C(C=C(C=C1)Cl)C

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

AZFKQCNGMSSWDS-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C11H13ClO2S/c1-3-15-11(13)7-14-10-5-4-9(12)6-8(10)2/h4-6H,3,7H2,1-2H3

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
MCPA	Derivative

General status

Pesticide type

Herbicide

Substance group

Aryloxyalkanoic acid

Minimum active substance purity

920 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Selective, systemic with translocation. Synthetic auxin.

CAS RN

25319-90-8

EC number

246-831-4

CIPAC number

8205

US EPA chemical code

431500

PubChem CID

32876

Molecular mass

244.74

PIN (Preferred Identification Name)

S-ethyl (4-chloro-2-methylphenoxy)ethanethioate

IUPAC name

S-ethyl 4-chloro-o-tolyloxythioacetate

CAS name

S-ethyl (4-chloro-2-methylphenoxy)ethanethioate

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Classification (HRAC)

Herbicide Resistance Classification (WSSA)

Insecticide Resistance Classification (IRAC)

Not applicable

Fungicide Resistance Classification (FRAC)

Not applicable

Examples of recorded resistance

Physical state

Solid

Formulations

Property

Value

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

Example products using this active

Formulation and application details

Often supplied as soluble concentrate that is mixed with water and used as a spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

2.28

Low

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

1000000

Acetone

144000

Methanol

1000000

Ethyl acetate

1000000

Xylene

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

2.82 X 10⁰⁴

Calculated

Log P

4.45

High

Bulk density (g ml⁻¹)

1.291

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

0.13

Low volatility

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

0.2102

Moderately volatile

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

No absorption >290nm

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

4.4

Non-persistent

DT₅₀ (lab at 20 °C)

4.4

Non-persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Dissipation rate RL₅₀ on plant matrix

Value

Note

Dissipation rate RL₅₀ on and in plant matrix

Value

Note

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Moderately fast

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

Mobile

K_oc

Notes and range

EU dossier value for MCPA

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

1.37

Calculated

Low leachability

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

Value

3.58 X 10^-03

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Mobile

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

MCPA (Ref: BAS 009H)

Soil

0.66

Major fraction, Relevant

2-methyl-4-chlorophenol

Soil

0.198

Major fraction, Relevant

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

450

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)

> 400

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

> 1040 mg kg feed⁻¹

Colinus virginianus

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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

0.3

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

0.2

Salmo gairneri

Moderate

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

0.58

Daphnia magna

Moderate

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

0.009

Daphnia magna

High

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)

Non-target plants

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

> 2.3

Scenedemus subspicatus

Moderate

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)

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

> 100

as formulation

Low

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)

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 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)

140.5

Moderate

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

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

Soil micro-organisms

Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect

Dose: 1.224 kg ha⁻¹ 28 days

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)

450

Rat

Moderate

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

5000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.044

Rat 4 hr

Other Mammal toxicity endpoints

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

0.013

Rat SF=100

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

0.15

Rabbit SF=100

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

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

0.04

Rat SF=100

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

List II as MCPA

Exposure Routes

Public

Occupational

European MRLs

EU MRL pesticide database

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

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

Highly toxic

Handling issues

Property

Value and interpretation

General

Not explosive

CLP classification 2013

Health: H302
Environment: H400, H410

EC Risk Classification

Xn - Harmful: R22, R41
Xi - Irritant: R38

EC Safety Classification

S2, S26, S37, S39

WHO Classification

II (Moderately hazardous)

UN Number

Waste disposal & packaging

TRANSLATIONS

Language

Name

English

MCPA-thioethyl

French

German

Danish

Italian

Spanish

Greek

Polish

MCPA tioetyl

Swedish

Hungarian

Dutch

Record last updated:	12/01/2021
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