Dichlorprop (Ref: RD 406)

Dichlorprop (Ref: RD 406)	Last updated: 11/01/2021
(Also known as: 2,4-DP)

SUMMARY

Dichlorprop is a post-emergence, selective herbicide that does not have regulatory approval for use in the EU. It has a moderate aqueous solubility and is volatile. Its data suggests it is not persistent in soils but may persist in some water systems. It is moderately toxic to. Dichlorprop has a moderate to low toxicity to most aquatic organisms.

GENERAL INFORMATION

Description

A herbicide for post-emergence control of annual and perennial broad-leaved weeds and some brush species

Example pests controlled

Canada thistle; Cocklebur; Ragweeds; Pigweed; Shepherd's purse; Stinkweed; Lambsquarter; Goosefoot; Wild mustard

Example applications

Cereals including wheat, barley; Non-crop situations including right-of-way, commercial and industrial sites

Efficacy & activity

Availability status

Current

Introduction & key dates

1961

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

Not applicable

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

Also used in

Chemical structure

Isomerism

Chiral with S- and R- enantiomers

Chemical formula

C₉H₈Cl₂O₃

Canonical SMILES

CC(C(=O)O)OC1=C(C=C(C=C1)Cl)Cl

Isomeric SMILES

Clc1cc(Cl)ccc1OC(C(=O)O)C

International Chemical Identifier key (InChIKey)

MZHCENGPTKEIGP-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C9H8Cl2O3/c1-5(9(12)13)14-8-3-2-6(10)4-7(8)11/h2-5H,1H3,(H,12,13)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
dichlorprop	-

General status

Pesticide type

Herbicide

Substance group

Aryloxyalkanoic acid

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Selective, systemic, absorbed through leaves and translocates to roots. Synthetic auxin causing stem and leaf malformations leading to death.

CAS RN

120-36-5

Alternative/old CAS RN

7547-66-2

EC number

204-390-5

CIPAC number

US EPA chemical code

031401

PubChem CID

8427

Molecular mass

235.06

PIN (Preferred Identification Name)

rac-(2R)-2-(2,4-dichlorophenoxy)propanoic acid

IUPAC name

(RS)-2-(2,4-dichlorophenoxy)propionic acid

CAS name

2-(2,4-dichlorophenoxy)propanoic acid

Other status information

Potential groundwater contaminant

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

Colourless crystals

Formulations

Property

Value

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

Weedone 170
Hedonal DP
Hormatox
Polyclene
Seritox
Polymore

Example products using this active

Headland Agrochemicals
FBC
Bayer
Universal Crop Protection

Formulation and application details

Often supplied as an emulsifiable concentrate or as an emulsion.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

350

Moderate

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

689000

Ethyl acetate

1265000

Acetone

3030

Hexane

61200

Toluene

Melting point (°C)

117

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

204

(open cup)

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

1.95 X 10⁰²

Calculated

Log P

2.29

Low

Bulk density (g ml⁻¹)

1.42

Dissociation constant pKa) at 25 °C

Strong acid

Vapour pressure at 20 °C (mPa)

0.01

Low volatility

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

8.80 X 10^-06

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)

Non-persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Other sources: DT₅₀ 21-25 days (R3)

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

Note

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

Value

Stable

Note

Water-sediment DT₅₀ (days)

Fast

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

Other sources: 12.0-170 mL g⁻¹ (R3)

Freundlich

K_f

0.77

Mobile

K_foc

41.2

¹/_n

0.87

Notes and range

K_f range 0.67-0.86 mL g⁻¹, K_foc range 34.4-47.9 mL g⁻¹, ¹/_n range 0.86-0.88, Soils=2

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.39

Calculated

Transition state

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

Value

5.07 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

2,4-dichlorophenol

Soil

Minor fraction; Relevant

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

Estimated

Low potential

CT₅₀ (days)

Not available

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

825

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

(ppm diet)

> 5

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

Birds - Acute LD₅₀ (mg kg⁻¹)

504

Coturnix japonica

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)

> 0.5

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

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

> 100

Daphnia magna

Low

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)

Non-target plants

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

1100

Pseudokirchneriella subcapitata

Low

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

180

Unknown species

Low

Honeybees (Apis spp.)

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

Moderate

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

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)

1000

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

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)

825

Rat

Moderate

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

1400

Mouse

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.65

Rat

Other Mammal toxicity endpoints

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

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 II

Exposure Routes

Public

Low risk to Europeans as no longer approved for use

Occupational

Low risk to Europeans as no longer approved for use

European MRLs

EU MRL pesticide database

Drinking Water Standards

Non-statutory WHO drinking water guideline 0.1 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

; ; ; ;

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

No further information available

Handling issues

Property

Value and interpretation

General

No information available

CLP classification 2013

Health: H302, H312, H315, H318

EC Risk Classification

Xn - Harmful: R21/22, R41
Xi - Irritant: R38

EC Safety Classification

S2, S22, S36/37

WHO Classification

II (Moderately hazardous)

UN Number

Waste disposal & packaging

TRANSLATIONS

Language

Name

English

dichlorprop

French

dichlorprop

German

Dichlorprop

Danish

dichlorprop

Italian

diclorprop

Spanish

diclorprop

Greek

dichlorprop

Polish

dichlorprop

Swedish

Hungarian

dichlorprop

Dutch

dichloorprop

Record last updated:	11/01/2021
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