Fluroxypyr (Ref: DOW 43304-H)

Fluroxypyr (Ref: DOW 43304-H)	Last updated: 19/12/2024
(Also known as: fluroxypyr acid)

SUMMARY

Fluroxypyr is a post-emergence herbicide used to control economically important broad-leaved weeds. It is highly soluble in water and has a low volatility. It tends not to be persistent in soil or water-sediment systems. There is little potential for it to leach to groundwater. No significant risks to human health have been identified other than some indication it may be a neurotoxin and oral mammalian toxicity is low. Toxicity to biodiversity is low to moderate.

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 chronic ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Bees acute oral ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health High alert: Neurotoxicant

GENERAL INFORMATION

Description

A post-emergence herbicide used to control economically important broad-leaved weeds

Example pests controlled

Annual and perennial broad-leaved weeds including kochia, lespedeza and dogfennel; Woody brush

Example applications

Rangeland; Permanent pasture; Non-crop areas; Cereals including wheat, corn; Orchards; Vineyards

Efficacy & activity

Availability status

Current

Introduction & key dates

1983, first reported; 1985, first introduced UK

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

31/12/2029

GB LERAP status

Check label - may vary with formulation

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Sweden/Slovenia

Date EC 1107/2009 inclusion expires

31/12/2024

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

USA, Morocco

Chemical structure

Isomerism

None - fluroxypyr is not itself isomeric but the meptyl ester has a pair of enantiomers.

Chemical formula

C₇H₅Cl₂FN₂O₃

Canonical SMILES

C(C(=O)O)OC1=NC(=C(C(=C1Cl)N)Cl)F

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

MEFQWPUMEMWTJP-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C7H5Cl2FN2O3/c8-3-5(11)4(9)7(12-6(3)10)15-1-2(13)14/h1H2,(H2,11,12)(H,13,14)

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
fluroxypyr	-

General status

Pesticide type

Herbicide

Substance groups

Pyridine herbicide

Minimum active substance purity

950 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Foliar uptake causing auxin-type response. Synthetic auxin.

CAS RN

69377-81-7

EC number

614-957-2

CIPAC number

431

US EPA chemical code

128968

PubChem CID

50465

CLP index number

607-255-00-2

Molecular mass

255.03

PIN (Preferred Identification Name)

IUPAC name

4-amino-3,5-dichloro-6-fluoro-2-pyridyloxyacetic acid

CAS name

((4-amino-3,5-dichloro-6-fluoro-2-pyridinyl)oxy)acetic acid

Other status information

Marine pollutant

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

White crystalline solid

Related substances & organisms

fluroxypyr-meptyl

Formulations

Property

Value

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

AgriGuard
Dow AgroSciences
DuPont
Nufarm UK
Makhteshim-Agan

Example products using this active

Bastion T
Cabadex
Doxstar
Forefront
Galaxy
GL184
Starane
Tomahawk

Formulation and application details

Often supplied as an emulsion concentrate that is mixed with water and applied as a spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

6500

High

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

Hexane

35000

Methanol

300

Xylene

9200

Acetone

Melting point (°C)

232.5

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

360

Flashpoint (°C)

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

1.10 X 10⁰⁰

Calculated

Log P

0.04

Low

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data

Density (g ml⁻¹)

1.09

Dissociation constant pKa) at 25 °C

2.94

at 25°C

Strong acid

Vapour pressure at 20 °C (mPa)

3.8 X 10^-06

Low volatility

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

1.69 X 10^-10

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

pH 1.28: 210nm = 48780
pH 10.1: 211nm = 48030
pH 12.6: 218nm = 25980

Surface tension (mN m⁻¹)

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)

Non-persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

2.4

Non-persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

Data for MHE variant used. EU dossier lab studies DT₅₀ range 0.5-1.8 days (normalised); DT₉₀ range 1.0-6.0 days; Other studies: DT₅₀ 3-55 days (lab), 34-70 (field)

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

5.5

Note

Rice, whole plant, n=1

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Stable

Note

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

Value

223

Persistent

Note

Stable pH 4 to pH 7, DT₅₀ 3.2 days at pH 9

Water-sediment DT₅₀ (days)

34.7

Moderately fast

Water phase only DT₅₀ (days)

10.5

Moderately fast

Sediment 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)

1.20

Mobile

K_foc (mL g⁻¹)

¹/_n

0.93

Notes and range

EU dossier (2011) kf range 0.11-1.90 mL g⁻¹, K_foc range 51-81 mL g⁻¹, ¹/_n range 0.88-0.92, Soils=4

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.03

Calculated

Low leachability

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

Value

2.33 X 10^-03

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

13.35

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)

62.1

Whole fish

Low potential

CT₅₀ (days)

Not available

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

4-amino-3,5-dichloro-6-fluoro-2-pyridinol

Major fraction

4-amino-3,5-dichloro-6-fluoro-2-pirydynil-2-methoxypyridine

Major fraction

Known groundwater metabolites

Metabolite

EC SANCO/221/2000 relevancy

ADI (mg kg⁻¹ bodyweight day⁻¹)

WHO drinking water guidance value (μg L⁻¹ day⁻¹)

4-amino-3,5-dichloro-6-fluoro-2-pyridinol

Relevancy unknown

4-amino-3,5-dichloro-6-fluoro-2-pirydynil-2-methoxypyridine

Relevancy unknown

Other known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 2000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

> 80

Mice

High

(ppm diet)

> 200

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

500

Unknown species Reproductive NOAEL

Low

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2000

Anas platyrhynchos

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5000 ppm

Anas platyrhynchos

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

40.1

Anas platyrhynchos

Moderate

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

> 64.8

Eisenia foetida

Moderate

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

3.05

Eisenia foetida 56 day

Moderate

Soil micro-organisms

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

Dose: 2 kg ha⁻¹

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)

37.1

Apis mellifera

Moderate

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

Chronic

Notes

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

234.2

Aphidius rhopalosiphi Adult as the meptyl ester

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

> 396.0

Typhlodromus pyri Adult as the meptyl ester

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)

14.3

Lepomis macrochirus

Moderate

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 magna

Low

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)

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)

12.3

Lemna gibba

Low

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

49.8

Pseudokirchneriella subcapitata

Low

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

Unknown species

Low

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)

> 2000

Rat

Low

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 1.0

Rat 4 hr

Other Mammal toxicity endpoints

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

0.8

Rat SF=100

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)

0.8

Dermal penetration studies (%)

4.0-22

concentration dependent

Dangerous Substances Directive 76/464

List II

Exposure Routes

Public

Occupational

Occupational exposure to fluroxypyr may occur through inhalation and dermal contact

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

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

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
IMDG Transport Hazard Class 9

CLP classification 2013

Environment: H412

WHO Classification

U (Unlikely to present an acute hazard)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

fluroxypyr

French

fluroxypyr

German

Fluroxypyr

Danish

fluroxypyr

Italian

fluroxipir

Spanish

fluroxipir

Greek

fluroxypyr

Polish

fluroksypyr

Swedish

fluroxipyr

Hungarian

fluroxipir

Dutch

fluroxypyr

Norwegian

Record last updated:	19/12/2024
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