Dichlorprop-P-etexyl (Ref: CA2134)

Dichlorprop-P-etexyl (Ref: CA2134)	Last updated: 29/08/2024
(Also known as: 2,4-DP EHE; dichlorprop-P 2-EHE; dichlorprop-P 2-ethylyhexyl ester)

SUMMARY

Dichlorprop-P 2-ethylyhexyl ester is a herbicide and plant growth regulator. It has a low aqueous solubility and a low volatility. It is not expected to be persistent in soil systems but may be persistent in aquatic systems depending on local conditions. It has a moderate toxicity to bds and aquatic species but is less toxic to honeybees. Dichlorprop-P 2-ethylyhexyl ester is moderately toxic to mammals via the oral route. It is also a reproduction/developmental toxin and a skin sensitiser.

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: Drainflow: Mobile	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate	Human health High alert: Reproduction/development effects

GENERAL INFORMATION

Description

An ester of dichlorprop-P, mainly used as a plant growth regulator for citrus

Example pests controlled

Fruit size; Anti-drop

Example applications

Oranges; Lemons; Grapefruit; Mandarins

Efficacy & activity

Extensive historic use has demonstrated its effectiveness

Availability status

Current

Introduction & key dates

1987, introduced

GB regulatory status

GB COPR regulatory status

Approved (as dichloprop-P)

Date COPR inclusion expires

30/04/2029

GB LERAP status

None

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved (as dichloprop-P)

Dossier rapporteur/co-rapporteur

Ireland/Poland

Date EC 1107/2009 inclusion expires

15/03/2025

EU Candidate for substitution (CfS)

Listed in EU database

Yes (as dichlorprop-P)

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

Chemical structure

Isomerism

The R-enantiomer of dichlorprop-etexyl

Chemical formula

C₁₇H₂₄Cl₂O₃

Canonical SMILES

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

Isomeric SMILES

CCCCC(CC)COC(=O)[C@@H](C)OC1=C(C=C(C=C1)Cl)Cl

International Chemical Identifier key (InChIKey)

CEEDFYRUPAWDOU-PZORYLMUSA-N

International Chemical Identifier (InChI)

InChI=1S/C17H24Cl2O3/c1-4-6-7-13(5-2)11-21-17(20)12(3)22-16-9-8-14(18)10-15(16)19/h8-10,12-13H,4-7,11H2,1-3H3/t12-,13?/m1/s1

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide, Plant Growth Regulator

Substance groups

Aryloxyalkanoic acid herbicide; Phenoxypropionic herbicde; Auxin PGR

Minimum active substance purity

920 g kg⁻¹

Known relevant impurities

EU dossier: 2,4-dichlorophenol <3.0 g kg⁻¹; Dioxins & furans <0.01 mg kg⁻¹

Substance origin

Synthetic

Mode of action

Selective, systemic, absorbed by leaves and translocates to roots.

CAS RN

865363-39-9

EC number

682-532-9

CIPAC number

476

US EPA chemical code

PubChem CID

24843409

CLP index number

No data found

Molecular mass

347.3

PIN (Preferred Identification Name)

IUPAC name

(2RS)-2-ethylhexyl (2R)-2-(2,4-dichlorophenoxy)propionate

CAS name

2-ethylhexyl (2R)-2-(2,4-dichlorophenoxy)propanoate

Other status information

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

Colourless to pale yellow liquid

Related substances & organisms

dichlorprop-P

dichlorprop-P-diethylammonium

dichlorprop-P-potassium

dichlorprop-P-sodium

Formulations

Property

Value

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

Example products using this active

Formulation and application details

Usually supplied as an emulsifiable concentrate applied as a high volume spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

0.17

Low

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

250000

n-Heptane

250000

p-Xylene

250000

Acetone

250000

Methanol

Melting point (°C)

Boiling point (°C)

300

Degradation point (°C)

Flashpoint (°C)

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

6.46 X 10⁰³

Calculated

Log P

3.81

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

0.54

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

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

1.1

Moderately volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Neutral pH: 230nm=9130, 285nm=1950, 293nm=1680
Acid pH: 230nm=8920, 285nm=1940, 293nm=1670
Basic pH: 230nm=8950, 285nm=1930, 292nm=1660

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

1.1

Non-persistent

DT₅₀ (lab at 20 °C)

1.1

Non-persistent

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

6.6

Non-persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

1.69

Worse case

Note

EU 2017 dossier lab studies DT₅₀ range 0.76-1.69 days, DT₉₀ range 2.5-5.6 days, Soils=4

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

Unstable

Note

Expected to rapidly convert to dichlorprop-P

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

Value

120

Persistent

Note

Unstable at pH 9

Water-sediment DT₅₀ (days)

Water 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)

Mobile

K_foc (mL g⁻¹)

35.96

¹/_n

0.799

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.10

Calculated

Low leachability

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

Value

9.66 X 10^-04

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

23.23

Calculated using the Atkinson method. Assumed 0.5E+06 OH/cm³, 24 hr

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Known soil metabolites

Metabolite

Major/Minor fraction

$Click here for further information on Major/Minor fraction$

Estimated maximum occurrence fraction

Notes

dichlorprop-P (Ref: BAS 044H)

Major fraction

0.916

Known groundwater metabolites

None

Other known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 824

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)

1010

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

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

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Honeybees (Apis spp.)

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

> 180

Apis mellifera

Low

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

> 178.1

Apis mellifera

Low

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

Chronic

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)

Beneficial insects (Parasitic wasps)

Beneficial insects (Predatory mites)

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)

10.2

Oncorhynchus mykiss

Moderate

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

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

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

> 1.5

Daphnia magna

Moderate

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

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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)

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

6.7

Selenastrum capricornutum

Moderate

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

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves – Acute EC₅₀ development (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)

> 824

Rat

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

4.1

Rat 4 hr

Other Mammal toxicity endpoints

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

0.06

Mouse SF=100

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

0.2

Rat SF=100

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

0.2

Rat SF=100

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

0.08

Rat SF=100

Dermal penetration studies (%)

19-45

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Negligible risk to bystanders

Occupational

PPE/PPC recommended to reduce exposure risk

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

Extensive absorption, rapid excretion mainly via urine

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

General human health issues

Highly toxic
Possible kidney, liver & blood toxicant
May cause allergic skin reaction

Handling issues

Property

Value and interpretation

General

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

CLP classification 2013

Health: H302, H315, H317

WHO Classification

Not listed (Not listed)

UN Number

UN3077

Waste disposal & packaging

Packaging Group II (moderate danger)

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

dichlorprop-P-etexyl

French

German

Danish

Italian

Spanish

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	29/08/2024
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