Mecoprop-P (Ref: BAS 037H)

Mecoprop-P (Ref: BAS 037H)	Last updated: 20/05/2025
(Also known as: CMPP-P; MCPP-P; mechlorprop-P; RP 591066)

SUMMARY

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: GUS: High leachability; Drainflow: Mobile	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Birds chronic ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Bees acute contact ecotoxicity: Moderate; Bees acute oral ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health High alert: Mammals chronic toxicity: High; Reproduction/development effects

GENERAL INFORMATION

Description

A herbicide for post-emergence control of broadleaved weeds in grass and winter cereals

Example pests controlled

Cleavers; Chickweed; Clover; Plantains; Ground ivy; Knotweed; Bluegrasses; Bent grass

Example applications

Lawns; Sports fields; Golf courses; Fairways; Cereals including wheat, barley, oats, triticale

Efficacy & activity

Well established herbicide used across the Europe for broad leaved weed control for many years.

Availability status

Current

Introduction & key dates

1987, registered Germany

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

31/12/2027

GB LERAP status

None

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Ireland

Date EC 1107/2009 inclusion expires

15/10/2027

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
✓		✓	✓	✓			✓	✓

Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries

ISIceland	NONorway
✓	✓

Additional information

Also used in

Australia

Chemical structure

Isomerism

Mecoprop-P is the herbicidally active D+ isomer of chiral mecoprop.

Chemical formula

C₁₀H₁₁ClO₃

Canonical SMILES

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

Isomeric SMILES

CC1=C(C=CC(=C1)Cl)O[C@H](C)C(=O)O

International Chemical Identifier key (InChIKey)

WNTGYJSOUMFZEP-SSDOTTSWSA-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)/t7-/m1/s1

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
mecoprop	Isomer mix

General status

Pesticide type

Herbicide

Substance groups

Phenoxypropionic herbicide

Minimum active substance purity

890 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Selective, systemic, absorbed through leaves and translocated to roots. Synthetic auxin.

CAS RN

16484-77-8

EC number

240-539-0

CIPAC number

475

US EPA chemical code

129046

PubChem CID

185588

CLP index number

607-434-00-5

Molecular mass

214.65

PIN (Preferred Identification Name)

IUPAC name

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

CAS name

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

Other status information

Potential groundwater contaminant

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Herbicide Resistance Class (WSSA MoA class)

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

White to light brown crystalline solid

Related substances & organisms

mecoprop-P dimethylammonium

mecoprop-P etexyl

mecoprop-P potassium

mecoprop-P isobutyl

Formulations

Property

Value

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

BASF
Belchim
Certis
Headland
Nufarm
Scotts

Example products using this active

Compitox Plus
Di-Farmon R
Foundation
Optica
Prompt
Relay P
Duplosan
Mecoprop-P K600

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)

250000

High

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

250000

Acetone

250000

Ethyl acetate

250000

Methanol

250000

Dichloromethane

Melting point (°C)

93.5

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

240

Flashpoint (°C)

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

6.46 X 10^-01

Calculated

Log P

-0.19

Low

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data

Density (g ml⁻¹)

1.31

Dissociation constant pKa) at 25 °C

3.7

Weak acid

Vapour pressure at 20 °C (mPa)

1.40

at 25 °C

Low volatility. If applied directly to plants or soil, drift is a concern & mitigation is advisable

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

1.7 X 10^-04

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

0.1

Volatilisation is not considered critical for air pollution

From soil surface

1.0

Volatilisation is not considered critical for air pollution

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

Neutral soln: 229nm=9530, 280nm=1470, 285nm=1290, no absorption above 400nm
Acid soln: 227nm=8860, 279nm=1340, 284 nm=1770, no absorption above 400nm
Alkaline soln: 229nm=9520, 280nm=1560, 289nm=1360, no absorption above 400nm

Surface tension (mN m⁻¹)

at 20 °C 99.8%

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

5.24

Non-persistent

DT₅₀ (lab at 20 °C)

5.24

Non-persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

25.5

Non-persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ (normalised) range 4.0-8.2 days, DT₉₀ (measured) range 19.9-33.6 days, Soils=4; Other field studies: DT₅₀ 5-17 days

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) 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

Stable

Note

Stable pH 5 to pH 9 at 25 & 70 °C

Water-sediment DT₅₀ (days)

141

Slow

Water phase only DT₅₀ (days)

Stable

Sediment 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)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

1.54

Mobile

K_foc (mL g⁻¹)

59.8

¹/_n

0.85

Notes and range

EU 2016 RAR dossier K_f range 0.3-4.5 mL g⁻¹, K_foc range 12-167 mL g⁻¹, ¹/_n range 0.66-1.01, Soils=10

pH sensitivity

Adsorption higher at lower pH

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.94

Calculated

High leachability

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

Value

2.07 X 10^-01

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Mobile

Calculated

Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk

Calculated using the Atkinson method. Assumed 5.0 E+06 OH/cm³, 24 hr

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

Low potential

CT₅₀ (days)

1.1

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

hydroxymethyl-mecoprop-P

HMCPP

Plant; Rat

carboxymecoprop-P

CCPP

Plant; Rat

o-cresol

2-methylphenol

Water (photolysis); Sediment

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

431

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

> 20

Mice

High

(ppm diet)

> 100

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

Rat Reproductive NOAEL

High

Birds - Acute LD₅₀ (mg kg⁻¹)

> 500

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5600 mg kg feed⁻¹

Unknown species

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

70.9

Coturnix japonica NOAEL

Moderate

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

> 988

Eisenia foetida

Moderate

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

10.8

Eisenia foetida

Moderate

Soil micro-organisms

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

Dose: 33.6 kg ha⁻¹

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

52.9

Folsomia candida

Non-target plants

Honeybees (Apis spp.)

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

> 83.0

Apis mellifera

Moderate

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

> 83.0

Apis mellifera

Moderate

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

Chronic as 10-day LDD₅₀ µg bee⁻¹ day⁻¹

89.3

Apis mellifera

Notes

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)

2.8% Mortality at dose 876 g ha⁻¹

Chrysoperla carnea

Beneficial insects (Parasitic wasps) as Mortality LR₅₀ g ha⁻¹

447.6

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹

> 1468

Typhlodromus pyri

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)

> 93

Oncorhynchus mykiss

Moderate

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

> 50

Oncorhynchus mykiss

Low

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

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

> 91

Daphnia magna

Moderate

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

22.7

Daphnia magna

Low

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (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 (free-floating, growth) - Acute 7 day EC₅₀, biomass (mg l⁻¹)

1.6

Lemna gibba

Moderate

Aquatic plants (rooted, growth) - Acute 14 day EC₅₀, biomass (mg l⁻¹)

0.0027

Myriophyllum spicatum

High

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

16.2

Unknown species

Low

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

Unknown species

Low

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves – Acute EC₅₀ (mg l⁻¹)

78.8

Crassostrea gigas Embryo

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)

431

Rat

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 2.13

Rat 4 hr (whole body)

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)

0.2 Rabbit, SF=100

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

0.2

Rabbit

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

0.04

Dog SF=100

Dermal penetration studies (%)

3-9

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

No unacceptable risks to operators or other workers using PPE/PPC identified

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Mammalian dose elimination route and rate

Largely lost as parent with minimal metabolism. Rapid elimination via urine usually within 48 hrs.

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

General human health issues

Possible kidney & liver toxicant
US EPA - weak evidence to suggest possible human carcinogen

Handling issues

Property

Value and interpretation

General

Prevent generation of mists
Not explosive or oxidising
IMDG Transport Hazard Class 9
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H361, H302, H318
Environment: H411

WHO Classification

II (Moderately hazardous)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Chemically stable under standard ambient conditions

TRANSLATIONS

Language

Name

English

mecoprop-P

French

mecoprop-P

German

Mecoprop-P

Danish

mechlorprop-P

Italian

mecoprop-P

Spanish

mecoprop-P

Greek

mecoprop-P

Polish

mekoprop-P

Swedish

mekoprop-P

Hungarian

mecoprop-P

Dutch

mecoprop-P

Norwegian

mekoprop-P

Record last updated:	20/05/2025
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