Ethephon

Ethephon	Last updated: 22/08/2024
(Also known as: chlorethephon; 2-CEPA; 2-chloroethylphosphonic acid)

SUMMARY

Ethephon, which is also known as chlorethephon and 2-CEPA, is a plant growth regulator which is approved for use in the UK and the EU. It is highly soluble in water and many organic solvents. It is not considered persistent in soils but can be in water bodies under certain conditions. Based on its physico-chemical parameters, ethephon is not expected to leach to groundwater. It’s ecotoxicity is considered low to moderate for most species. There are concerns regarding its toxicity to humans being moderately toxic via the oral route, an acetyl cholinesterase inhibitor, neurotoxin and irritant.

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 Moderate alert: Drainflow: Slightly mobile; Potential for particle bound transport: Medium	Ecotoxicity Moderate alert: Birds acute ecotoxicity: Moderate; Birds chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate	Human health High alert: Acetyl cholinesterase inhibitor; Neurotoxicant

GENERAL INFORMATION

Description

A plant growth regulator with a range of uses including the prevention of lodging in cereals and promotion of pre-harvest ripening of fruit.

Example pests controlled

Lodging

Example applications

Cereals; Fruit including pineapples, bush fruit; Coffee; Ornamentals; Tobacco; Rubber

Efficacy & activity

Efficiacy demonstrated from long-term field use

Availability status

Current

Introduction & key dates

circa 1982, introduced

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

31/07/2029

GB LERAP status

None

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Netherlands/Poland

Date EC 1107/2009 inclusion expires

31/01/2039

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, USA

Chemical structure

Isomerism

None

Chemical formula

C₂H₆ClO₃P

Canonical SMILES

C(CCl)P(=O)(O)O

Isomeric SMILES

None

International Chemical Identifier key (InChIKey)

UDPGUMQDCGORJQ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C2H6ClO3P/c3-1-2-7(4,5)6/h1-2H2,(H2,4,5,6)

2D structure diagram/image available?

Yes

General status

Pesticide type

Plant Growth Regulator

Substance groups

Ethylene emitter

Minimum active substance purity

910 g kg⁻¹

Known relevant impurities

EU dossier - 1,2-dichloroethane; MEPHA

Substance origin

Synthetic

Mode of action

Systemic, translocates. Ethylene producer.

CAS RN

16672-87-0

EC number

240-718-3

CIPAC number

373

US EPA chemical code

099801

PubChem CID

27982

CLP index number

015-154-00-4

Molecular mass

144.49

PIN (Preferred Identification Name)

(2-chloroethyl)phosphonic acid

IUPAC name

2-chloroethylphosphonic acid

CAS name

(2-chloroethyl)phosphonic acid

Other status information

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Not applicable

Herbicide Resistance Class (WSSA MoA class)

Not applicable

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

White crystals

Related substances & organisms

chlormequat chloride

mepiquat chloride

Formulations

Property

Value

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

BASF
Bayer CropScience
Kingtai Chemicals
Globachem
Union Carbide
Cotton Growers Services Pty Ltd
ADAMA Australia Pty Ltd

Example products using this active

Cerone
Cyclade
Sypex
Terpal
Upgrade
Forgrow
Florel
CGS Prep 900 Growth Regulator
Promote Plus 900 Growth Regulator

Formulation and application details

Often supplied as a liquid concentrate for dilution and use as a foliar spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

1000000

High

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

300

n-Heptane

600000

Methanol

600000

Acetone

600000

Ethyl acetate

Melting point (°C)

73.3

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

110

Flashpoint (°C)

111

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

1.29 X 10^-02

Calculated

Log P

-1.89

Low

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data

Density (g ml⁻¹)

1.65

Dissociation constant pKa) at 25 °C

2.82

pKa(2) 7.21

Vapour pressure at 20 °C (mPa)

4.5 X 10^-02

Low volatility

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

6.5 X 10^-09

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

No absorption 225-800nm, 200nm=25

Surface tension (mN m⁻¹)

98.5

at 20°C

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

13.1

Non-persistent

DT₅₀ (lab at 20 °C)

13.1

Non-persistent

DT₅₀ (field)

13.5

Non-persistent

DT₉₀ (lab at 20 °C)

71.0

Moderately persistent

DT₉₀ (field)

60.9

DT₅₀ modelling endpoint

Note

EU 2017 dossier lab studies range 2.7-57.8 days, DT₉₀ range 11.7-289 days, Soils=7; field studies DT₅₀ range 4.7-28.4 days, DT₉₀ range 24.2-105.2 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

40.4

Stable

Note

DT₅₀ 29.4 days in the light, 51.4 days in the dark

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

Value

2.5

Non-persistent

Note

pH sensitive: 99.1 days at pH 5, 1.4 days at pH 9, 20 °C

Water-sediment DT₅₀ (days)

2.8

Fast

Water phase only DT₅₀ (days)

2.4

Moderately fast

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)

29.9

Slightly mobile

K_foc (mL g⁻¹)

2540

¹/_n

0.992

Notes and range

EU dossier K_f range 2.37-57.33 mL g⁻¹, K_foc range 608-4078 mL g⁻¹, ¹/_n range 0.977-1.007, Soils=5

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.67

Calculated

Low leachability

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

Value

1.11 X 10^-02

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Slightly mobile

Calculated

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

244.8

Calculated using the Atkinson method

Substance of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

No data

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

ethylene gas

Aerobic

2-hydroxy ethyl phosphonic acid

Photolysis

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)

1564

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Mice

High

(ppm diet)

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

133

Rat NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

764

Colinus virginianus

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

> 450 mg kg bw⁻¹ day⁻¹

Colinus virginianus

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

88.0

Anas platyrhynchos NOAEL

Moderate

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

> 165.4

Eisenia foetida

Moderate

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

>= 200

Eisenia foetida 56 day

Low

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

> 410

Folsomia candida

Non-target plants

134

Cucumber
Vegetative vigour, ER₅₀
as g ha⁻¹

187

Mustard
Seedling emergence, ER₅₀
as g ha⁻¹

Honeybees (Apis spp.)

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

> 100

Apis mellifera

Low

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

> 116.5

Apis mellifera

Low

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

Chronic as 10-day LC₅₀ µg bee⁻¹ day⁻¹

> 40.46

Apis mellifera

Bumblebees (Bombus spp.)

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

> 100

Bombus terrestris

Low

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

> 167

Bombus terrestris

Low

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) as Mortality LR₅₀ g ha⁻¹

> 726

Chrysoperla carnea

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

465

Aphidius rhopalosiphi

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

> 726

Typhlodromus pyri

Beneficial insects (Ground beetles) as Mortality LR₅₀ g ha⁻¹

> 726

Poecilus cupreus

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

> 100

Cyprinus carpio

Low

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

Pimephales promelas 34 day

Low

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

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

90.4

Daphnia magna

Moderate

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

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)

> 89

Chironomus tentans 48 hr

Moderate

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)

1.5

Lemna gibba

Moderate

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

> 2.86

Navicula pelliculosa

Moderate

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

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

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)

1564

Rat

Moderate

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

983

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

3.26

Rat 4 hr (whole body)

Other Mammal toxicity endpoints

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

0.03

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

0.05

Human SF=10

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

1.7

Rat SF=300

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

0.03

Dermal penetration studies (%)

1.0-5.0

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

Risk acceptable with PPE/PPC

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

Mainly urinary excretion (~60%), some faecal loss (4-7%) and loss via exhaled ethylene

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

Eye irritant

Phototoxicant

No data found

General human health issues

May cause cardiac abnormalities

Handling issues

Property

Value and interpretation

General

Corrosive
Not explosive or oxidising
Hygroscopic
IMDG Transport Hazard Class 6.1

CLP classification 2013

Health: H302, H311, H314, H332
Environment: H411

WHO Classification

III (Slightly hazardous)

UN Number

UN2928

Waste disposal & packaging

Packaging Group II (moderate danger)

Shelf-life, storage, stability and reactivity

Chemically stable under standard ambient conditions

TRANSLATIONS

Language

Name

English

ethephon

French

ethephon

German

Ethephon

Danish

ethephon

Italian

etefon

Spanish

etefon

Greek

ethephon

Polish

etefon

Swedish

etefon

Hungarian

etefon

Dutch

ethefon

Norwegian

etefon

Record last updated:	22/08/2024
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