Mecoprop (Ref: RD 4593)

Mecoprop (Ref: RD 4593)	Last updated: 18/02/2021
(Also known as: MCPP; mechlorprop; CMPP; mecoprop acid)

GENERAL INFORMATION

Description

A post-emergence herbicide used to control broad-leaved weeds on non-crop areas

Example pests controlled

Cleavers; Chickweed; Plantains; Clover; Ground ivy; Dandelions

Example applications

Turf including lawns, sports fields; Commercial sod production; Drainage ditches; Rights-of-way

Efficacy & activity

Availability status

Current

Introduction & key dates

circa 1956

UK regulatory status

UK COPR regulatory status

Not approved

Date COPR inclusion expires

Not applicable

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

Denmark

Date EC 1107/2009 inclusion expires

Not applicable

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

Australia, USA

Chemical structure

Isomerism

Technical mecoprop is chiral and an isomeric mixture of enantiomers of which only one form, the D+ isomer is herbicidally active and which is contained in the racemate in equal proportion to the L- form.

Chemical formula

C₁₀H₁₁ClO₃

Canonical SMILES

CC1=C(C=CC(=C1)Cl)OC(C)C(=O)O

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

WNTGYJSOUMFZEP-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C10H11ClO3/c1-6-5-8(11)3-4-9(6)14-7(2)10(12)13/h3-5,7H,1-2H3,(H,12,13)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
mecoprop	Unstated isomer

General status

Pesticide type

Herbicide

Substance group

Aryloxyalkanoic acid

Minimum active substance purity

930 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Selective, systemic, absorbed by leaves with translocation. Synthetic auxin.

CAS RN

7085-19-0

Alternative/old CAS RN

93-65-2

EC number

202-264-4

CIPAC number

US EPA chemical code

031501

PubChem CID

7153

Molecular mass

214.65

PIN (Preferred Identification Name)

IUPAC name

(RS)-2-(4-chloro-o-tolyloxy)propionic acid

CAS name

2-(4-chloro-2-methylphenoxy)propanoic acid

Other status information

Potential groundwater contaminant

Relevant Environmental Water Quality Standards

UK statutory standard for surface water quality: ‘Good’ for freshwater, transitional and coastal waters 20 µg l⁻¹

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

White to light brown crystalline solid

Formulations

Property

Value

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

Iso-Cornox
MecoPex
Propal
Mepro
Methoxone

Example products using this active

Nufarm
BASF
FBC
Rhone-Poulenc
Universal Crop Protection

Formulation and application details

Usually supplied as a liquid concentrate or as an emulsifiable concentrate

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

250000

High

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

4110

n-Heptane

126000

Xylene

1000000

Methanol

469000

Ethyl acetate

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

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

6.46 X 10^-01

Calculated

Log P

-0.19

Low

Bulk density (g ml⁻¹)

1.37

Dissociation constant pKa) at 25 °C

3.11

Weak acid

Vapour pressure at 20 °C (mPa)

1.6

Low volatility

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

2.20 X 10^-04

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)

8.2

Non-persistent

DT₅₀ (lab at 20 °C)

8.2

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

3.8

Note

Published literature RL₅₀ range 3.0-4.7 days, 2 field crops, various matrices, n=2

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Stable

Note

pH sensitive: DT₅₀ 42 days at pH 5, 44 days at pH 7, 32 days at pH 9

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

Value

Stable

Note

Stable pH 5 to pH 9 up to 70 °C, 8 days

Water-sediment DT₅₀ (days)

Moderately fast

Water phase only DT₅₀ (days)

Stable

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

Mobile

K_oc

Notes and range

Freundlich

K_f

0.41

Mobile

K_foc

¹/_n

Notes and range

EU dossier K_f range 0.2-0.69 mL g⁻¹, K_foc range 20-43 mL g⁻¹, Soils=4

pH sensitivity

Adsorption higher at lower pH

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.29

Calculated

Transition state

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

Value

2.90 X 10^-02

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

2-methyl-4-chlorophenol

Soil

0.035

Minor fraction, Relevancy unknown

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

Low potential

CT₅₀ (days)

1.1

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

1166

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

11.4

Rat

High

(ppm diet)

150

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 500

Anas platyrhynchos

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

5000 mg kg feed⁻¹

Anas platyrhynchos

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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

240

Unknown species

Low

Fish - Chronic 21 day NOEC (mg l⁻¹)

109

Oncorhynchus mykiss

Low

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

> 200

Daphnia magna

Low

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

22.0

Daphnia magna

Low

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)

40.2

Unknown species

Low

Non-target plants

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

237

Unknown species

Low

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

Unknown species

Low

Honeybees (Apis spp.)

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

> 100

Low

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

> 100

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)

988

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

-28

Mortality [Dose: 3.36 g ha⁻¹]
Carabus nemoralis

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

Beneficial effect [Dose: 3.36 g ha⁻¹]
Philonthus marginatus

Soil micro-organisms

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

Dose: 33.6 kg ha⁻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)

1166

Rat

Moderate

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

4000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

12.5

Rat (nose only)

Other Mammal toxicity endpoints

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

0.01

Rat SF=100

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

None allocated

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 90 day SF=100

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

List II

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

No unacceptable risks to operators or other workers identified

MRLs

European

EU MRL pesticide database

Notes

Drinking Water Standards

Non-statutory WHO drinking water guideline 0.01 mg l⁻¹

UK EA QS database 2018

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

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

No further information available

Handling issues

Property

Value and interpretation

General

Hydrogen Chloride (HCl), and phosgene may be formed in a fire
IMDG Transport Code is usually 6.1

CLP classification 2013

Health: H302, H315, H318
Environment: H400, H410

EC Risk Classification

Xn - Harmful: R22, R41
Xi - Irritant: R38
N - Dangerous for the environment: R50, R53

EC Safety Classification

S2, S13, S26, S37/39, S60, S61

WHO Classification

II (Moderately hazardous)

UN Number

Usualy 2811

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

Language

Name

English

mecoprop

French

mecoprop

German

Mecoprop

Danish

mechlorprop

Italian

mecoprop

Spanish

mecoprop

Greek

mecoprop

Polish

mekoprop

Swedish

mekoprop

Hungarian

mecoprop

Dutch

mecoprop

Record last updated:	18/02/2021
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