Ioxynil octanoate

Ioxynil octanoate	Last updated: 15/02/2021
(Not known by any other names)

GENERAL INFORMATION

Description

A herbicide used for post-emergence control of various broad-leaved weeds

Example pests controlled

Annual broad-leaved weeds

Example applications

Cereals; Onions; Leeks; Garlic; Shallots; Flax; Sugarcane; Forage grasses; Lawns & turf

Efficacy & activity

Availability status

Current

Introduction & key dates

circa 1966

UK regulatory status

UK COPR regulatory status

Not approved

Date COPR inclusion expires

Expired

UK LERAP status

Not applicable

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

France

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

Australia

Chemical structure

Isomerism

Chemical formula

C₁₅H₁₇I₂NO₂

Canonical SMILES

CCCCCCCC(=O)OC1=C(C=C(C=C1I)C#N)I

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

QBEXFUOWUYCXNI-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C15H17I2NO2/c1-2-3-4-5-6-7-14(19)20-15-12(16)8-11(10-18)9-13(15)17/h8-9H,2-7H2,1H3

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance group

Hydroxybenzonitrile

Minimum active substance purity

920 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Selective, systemic with contact action. Photosynthetic electron transport inhibitor at the photosystem II.

CAS RN

3861-47-0

EC number

223-375-4

CIPAC number

US EPA chemical code

PubChem CID

19730

Molecular mass

497.1

PIN (Preferred Identification Name)

4-cyano-2,6-diiodophenyl octanoate

IUPAC name

4-cyano-2,6-diiodophenyl octanoate

CAS name

4-cyano-2,6-diiodophenyl octanoate

Other status information

Marine Pollutant

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

Fine white powder

Related substances & organisms

ioxynil

solvent naphtha

bromoxynil

ioxynil lithium

ioxynil sodium

Formulations

Property

Value

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

Alpha Briotril 24/16
Briotril Plus 19/19
Oxytril CM
Stellox

Example products using this active

Bayer CropScience
Makhteshim-Agan
NuFarm

Formulation and application details

Often supplied as a emulsifiable 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)

0.03

Low

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

1000000

Acetone

1000000

Ethyl acetate

111800

Methanol

1000000

Xylene

Melting point (°C)

56.6

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

240

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

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

1.00 X 10⁰⁶

Calculated

Log P

6.0

High

Bulk density (g ml⁻¹)

1.81

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

0.00009

Low volatility

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

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

227nm = 29738, 295nm = 1099

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)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ range 3-10days

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

6.9

Moderately fast

Note

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

Value

Non-persistent

Note

pH and temperature sensitive: stable at pH 4 and pH 5 both at 22-25 °C, DT₅₀ 6 days at pH 7 and 22 °C, 52 days at pH 7 and 25 °C, 16 days at pH 9 and 22 °C, 5.3 days pH 9 and 25 °C

Water-sediment DT₅₀ (days)

3.3

Fast

Water phase only DT₅₀ (days)

0.67

Fast

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

K_oc

Notes and range

Freundlich

K_f

3.94

Moderately mobile

K_foc

289

¹/_n

0.81

Notes and range

EU dossier K_f range 0.66-9.44 mL g⁻¹, K_foc range 64-786 mL g⁻¹, ¹/_n range 0.52-0.91

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.30

Calculated

Low leachability

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

Value

9.79 X 10^-03

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

Key metabolites

Metabolite

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

ioxynil (Ref: ACP 63-303)

Soil

0.526

Major fraction, Relevant

3,5-di-iodo-4-hydroxybenzamide

Major fraction, Relevant

3,5-di-iodo-4-hydroxybenzoic acid

Soil

Major fraction, Relevant

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

188

Whole fish

Threshold for concern

CT₅₀ (days)

Not available

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

165

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)

677

Coturnix japonica

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

2563 mg kg feed⁻¹

Coturnix japonica

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

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

0.043

Unknown species

High

Fish - Chronic 21 day NOEC (mg l⁻¹)

0.021

Unknown species

Moderate

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

0.011

Daphnia magna

High

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

0.010

Daphnia magna

Moderate

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)

0.01

Chironomus riparius

Moderate

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic plants - Acute 7 day EC₅₀, biomass (mg l⁻¹)

0.017

Lemna gibba

Moderate

Non-target plants

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

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

Honeybees (Apis 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)

> 3.27

Moderate

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)

> 60

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

55.6

Mortality [Dose: 0.625 kg ha⁻¹]
Aphidius rhopalosiphi adult

Other arthropod (2)

LR₅₀ g ha⁻¹

% Effect

98.7

Mortality [Dose: 0.625 kg ha⁻¹]
Typhlodromus pyri protonymph

Soil micro-organisms

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

Dose: 2.94 mg ioxynil octanoate/kg soil

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)

165

Rat

Moderate

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

4.36

Rat

Other Mammal toxicity endpoints

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

0.005

Rat SF=100

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

0.04

Rat SF=100

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

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

0.01

Rat SF=100

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

MRLs

European

EU MRL pesticide database

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

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

No data found

General human health issues

Possible thyroid toxicant

Handling issues

Property

Value and interpretation

General

IMDG Transport Code is usually 6.1

CLP classification 2013

Health: H301, H317, H319
Environment: H410

EC Risk Classification

Reproduction risk category 3: R63
T - Toxic: R25
Xn - Harmful: R43
Xi - Irritant: R36
N - Dangerous for the environment: R50, R53

EC Safety Classification

S1/2, S26, S36/37, S45, S60, S61

WHO Classification

II (Moderately hazardous)

UN Number

Usually 2588

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

Language

Name

English

ioxynil octanoate

French

German

Danish

Italian

Spanish

Greek

Polish

Swedish

ioxinil oktansyraester

Hungarian

Dutch

Record last updated:	15/02/2021
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