Prohexadione

Prohexadione	Last updated: 31/10/2024
(Also known as: DOCHC)

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 Moderate alert: Drainflow: Moderately mobile	Ecotoxicity Low alert: Birds acute ecotoxicity: Low; Fish acute ecotoxicity: Low; Fish chronic ecotoxicity: Low; Daphnia acute ecotoxicity: Low; Daphnia chronic ecotoxicity: Low; Bees acute contact ecotoxicity: Low; Bees acute oral ecotoxicity: Low; Earthworms acute ecotoxicity: Low	Human health High alert: Reproduction/development effects; Acetyl cholinesterase inhibitor

GENERAL INFORMATION

Description

A plant growth regulator used as an anti-lodging agent in small-grain cereals and to reduce vegetative growth in other crops

Example pests controlled

Growth

Example applications

Cereals including barley, oats and wheat; Turf; Apples; Pears; Peanuts

Efficacy & activity

Availability status

Current

Introduction & key dates

1994, introduced

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/12/2031

UK LERAP status

None

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

France/Ireland

Date EC 1107/2009 inclusion expires

31/05/2026

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

None

Chemical formula

C₁₀H₁₂O₅

Canonical SMILES

CCC(=O)C1C(=O)CC(CC1=O)C(=O)O

Isomeric SMILES

International Chemical Identifier key (InChIKey)

BUCOQPHDYUOJSI-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C10H12O5/c1-2-6(11)9-7(12)3-5(10(14)15)4-8(9)13/h5,9H,2-4H2,1H3,(H,14,15)

2D structure diagram/image available?

Yes

General status

Pesticide type

Plant Growth Regulator

Substance groups

Unclassified pesticide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Growth retardent. Gibberellin biosynthesis inhibitor.

CAS RN

88805-35-0

EC number

618-212-2

CIPAC number

567

US EPA chemical code

112600

PubChem CID

184900

CLP index number

No data found

Molecular mass

250.26

PIN (Preferred Identification Name)

3,5-dioxo-4-propanoylcyclohexane-1-carboxylic acid

IUPAC name

3,5-dioxo-4-propionylcyclohexanecarboxylic acid

CAS name

3,5-dioxo-4-(1-oxopropyl)cyclohexanecarboxylic 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 powder

Related substances & organisms

prohexadione-calcium

Formulations

Property

Value

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

BASF
Standon Chemicals

Example products using this active

Regalis
Medax Top (as calcium salt)
Canopy
Standon Midget

Formulation and application details

Often supplied as a wettable granules or as soluble concentrate that are 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)

786

High

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

0.01

Ethyl acetate

0.038

Acetone

0.003

Hexane

1.11

Methanol

Melting point (°C)

360

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

1.26 X 10^-03

Calculated

Log P

-2.9

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.46

Dissociation constant pKa) at 25 °C

5.15

Weak acid

Vapour pressure at 20 °C (mPa)

1.33 X 10^-02

Low volatility

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

1.92 X 10^-05

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 >290nm;Neutral solution: 273nm = 15400

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

0.7

Non-persistent

DT₅₀ (lab at 20 °C)

0.69

Non-persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

4.15

Non-persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ range 0.2-2.9 days (normalised), DT₉₀ range 0.7-39 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

DT₅₀ 6.3 days natural water, 2.7 days distilled water

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

Value

Moderately persistent

Note

pH sensitive: pH4 = 2.5 days, pH5 = 3.2 days, pH7 = 66 days, pH9 = Stable all at 25 °C

Water-sediment DT₅₀ (days)

1.8

Fast

Water phase only DT₅₀ (days)

1.8

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)

5.09

Moderately mobile

K_foc (mL g⁻¹)

204.5

¹/_n

1.0

Notes and range

EU dossier K_f range 0.49-10.12 mL g⁻¹, K_foc range 82.17-307 mL g⁻¹, ¹/_n range 0.93-1.04, Soils=4

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.76

Calculated

Low leachability

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

Value

3.21 X 10^-02

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

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

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

despropionyl prohexadione (Ref: KI5376)

Major fraction

0.152

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)

> 5000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

93.9

Rat 2 yr

High

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2000

Anas platyrhynchos

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 1214 mg kg bw⁻¹ day⁻¹

Colinus virginianus

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

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

> 1000

Eisenia foetida

Low

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

Soil micro-organisms

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

Dose: 0.69 mg kg⁻¹ 28 Day

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

> 1.5

Avena sativa Allium cepa Brassica napus
Vegetative vigour, ER₅₀
as L product ha⁻¹ (Regalis: Conc 100g kg⁻¹)

> 1.5

Avena sativa Allium cepa Brassica napus
Seeding emergence, ER₅₀
as L product ha⁻¹ (Regalis: Conc 100g kg⁻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)

> 100

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) as Mortality LR₅₀ g ha⁻¹

> 250

Aphidius rhopalosiphi as calcium variant

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

> 375

Typhlodromus pyri as calcium variant

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)

> 100

Oncorhynchus mykiss

Low

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

100

Oncorhynchus mykiss

Low

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

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

> 100

Daphnia carinata

Low

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

100

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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)

> 1.2

Lemna gibba

Moderate

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

> 100

Pseudokirchneriella subcapitata

Low

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

Intermediate (class II)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 4.21

Rat

Other Mammal toxicity endpoints

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

0.2

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)

0.35

Dermal penetration studies (%)

10-30

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks identified

Occupational

No unacceptable risks identified

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

GB MRL amended July 2021

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Mammalian dose elimination route and rate

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

Possible kidney toxicant

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H317

WHO Classification

Not listed (Not listed)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

prohexadione

French

prohexadione

German

Prohexadion

Danish

prohexadion

Italian

proesadione

Spanish

prohexadiona

Greek

Polish

proheksadion

Swedish

prohexadion

Hungarian

prohexadion

Dutch

Norwegian

Record last updated:	31/10/2024
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