clopyralid ** clopyralid-olamine ** Dowco 290 ** clopyralid acid ** 3,6-dichloropicolinic acid ** DCP ** Translations

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SUMMARY

A herbicide currently approved for use in the EU. It has a high aqueous solubility, is volatile and, based on its chemical properties, there is a high risk of it leaching to groundwater. It can be persistent in both soil and water systems depending upon conditions. It has a low mammalian toxicity and is not expected to bioaccumulate. It is an irritant. It is moderately toxic to birds, fish, aquatic invertebrates, honeybees and earthworms. It has a low toxicity to aquatic plants and algae.

GENERAL INFORMATION
for clopyralid

Description: A herbicide for a post-emergence control of many broad-leaved weeds in a range of crops

Example pests controlled: Broadleaved weeds generally; Capeweed; Volunteer peas; Thistles; Prickly lettuce; Knapweed; Volunteer vetch; Cape ivy

Example applications: Cereals including wheat, barley, oats, triticale; Turf; Ornamentals; Non-cropped and fallow land; Industrial situations

Efficacy & activity: Research supports the effectiveness of clopyralid to control a wide range of broadleaved weeds

Availability status: Current

Introduction & key dates: 1977, France

EC Regulation 1107/2009 (repealing 91/414):

Status	Approved
Dossier rapporteur/co-rapporteur	Finland/Poland
Date inclusion expires	30/04/2019
EU Candidate for substitution (CfS)	No
Listed in EU database	Yes

Approved for use () or known to be used () in the following European countries:

AT

BE

BG

CY

CZ

DE

DK

EE

EL

ES

FI

FR

HR

HU

IE

IT

LT

LU

LV

MT

NL

PL

PT

RO

SE

SI

SK

UK

Also used in: Australia, USA

Chemical structure:

Isomerism	-
Chemical formula	C6H3Cl2NO2
Canonical SMILES	C1=CC(=NC(=C1Cl)C(=O)O)Cl
Isomeric SMILES	No data
International Chemical Identifier key (InChIKey)	HUBANNPOLNYSAD-UHFFFAOYSA-N
International Chemical Identifier (InChI)	InChI=1S/C6H3Cl2NO2/c7-3-1-2-4(8)9-5(3)6(10)11/h1-2H,(H,10,11)
2D structure diagram/image available?	Yes

General status:

Pesticide type	Herbicide
Substance group	Pyridine compound
Minimum active substance purity	950 g/kg
Known relevant impurities	EU dossier - None declared
Substance origin	Synthetic
Mode of action	Selective, systemic, absorbed through leaves and roots. Synthetic auxin.
CAS RN	1702-17-6
EC number	216-935-4
CIPAC number	455
US EPA chemical code	117401
PubChem CID	15553
Molecular mass (g mol-1)	192.0
PIN (Preferred Identification Name)	3,6-dichloropyridine-2-carboxylic acid
IUPAC name	3,6-dichloropyridine-2-carboxylic acid
CAS name	3,6-dichloro-2-pyridinecarboxylic acid
Other status information	PAN Listed as Highly Hazardous Chemical; Potential groundwater contaminant
Relevant Environmental Water Quality Standards	-
Herbicide Resistance Classification (HRAC)	O
Herbicide Resistance Classification (WSSA)	4
Insecticide Resistance Classification (IRAC)	Not applicable
Fungicide Resistance Classification (FRAC)	Not applicable
Examples of recorded resistance	-
Physical state	Cream to white coloured crystals
Related substances & organisms	2,4-D MCPA diflufenican florasulam picloram triclopyr

Formulations:

Property	Value
Example manufacturers & suppliers of products using this active now or historically	AgriGuard Dow AgroSciences Teliton
Example products using this active	Esteem Galera Grazon 90 Stinger Lontrel Dowco 290
UK LERAP status	None
Formulation and application details	Usually supplied as a soluble concentrate, wettable powder or emulsifiable concentrate.

ENVIRONMENTAL FATE
for clopyralid

Property		Value	Source/Quality Score/Other Information	Interpretation
Solubility - In water at 20oC (mg l-1)		7850	A5	High
Solubility - In organic solvents at 20oC (mg l-1)		250000	A5 - Acetone	-
		102000	A5 - Ethyl acetate	-
		4600	A5 - Xylene	-
		6000	A5 - n-Hexane	-
Melting point (oC)		149.6	A5	-
Boiling point (oC)		Decomposes before boiling	A5	-
Degradation point (oC)		164	A5	-
Flashpoint (oC)		Not expected to self ignite; Not highly flammable	A5	-
Octanol-water partition coefficient at pH 7, 20oC	P	2.34 X 10-03	Calculated	-
	Log P	-2.63	A5	Low
Bulk density (g ml-1)/Specific gravity		1.76	A5	-
Dissociation constant (pKa) at 25oC		2.01	A5	-
		Note: Strong acid
Vapour pressure at 20oC (mPa)		1.36 X 10-09	A5	Low volatility
Henry's law constant at 25oC (Pa m3 mol-1)		1.80 X 10-11	A5	Non-volatile
GUS leaching potential index		4.51	Calculated	High leachability
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate	Value	1.04 X 10+00	Calculated	-
	Note	-
Potential for particle bound transport index		-	Calculated	Low
Maximum UV-vis absorption L mol-1 cm-1		Neutral solution: Maxima at 220nm, 280nm : 22100nm, 9200nm & 4790nm; [Acidic solution: Maxima at 202nm, 225nm, 281nm : 16200nm, 8890nm & 3800nm; [Basic solution: Maxima at 220nm, 279nm : 9300nm, 5030nm	A5	-
Surface tension (mN m-1)		71.5	A5 at 20 oC	-

Degradation:

Property		Value	Source/Quality Score/Other Information	Interpretation
General biodegradability		Not readily biodegradable
Soil degradation (days) (aerobic)	DT50 (typical)	23.2	A5	Non-persistent
	DT50 (lab at 20oC)	23.2	A5	Non-persistent
	DT50 (field)	8.2	A5	Non-persistent
	DT90 (lab at 20oC)	82.6	A5	-
	DT90 (field)	49.5	A5	-
	DT50 modelling endpoint	23.7	A5 representative of field studies	-
	Note	EU 2017 dossier lab studies DT50 range 4.9-64.6 days, DT90 range 16.2-214.6 days, Soils=10; field studies DT50 range 2.0-13.5 days, DT90 range 12.1-78.7 days; Other sources: DT50 40 days (R3)
Dissipation rate RL50 on plant matrix	Value	-	-	-
	Note	-
Dissipation rate RL50 on and in plant matrix	Value	5.4	R4	-
	Note	Published literature RL50 range 4.3-6.7 days, 3 field crops, various matrices, n=3
Aqueous photolysis DT50 (days) at pH 7	Value	271	A5	Stable
	Note	Not significant degradation route
Aqueous hydrolysis DT50 (days) at 20oC and pH 7	Value	Stable	A5	-
	Note	Stable pH 4 to pH 9, 50 degC
Water-sediment DT50 (days)		-	-	-
Water phase only DT50 (days)		148	A5	Stable

Soil adsorption and mobility:

Property		Value	Source/Quality Score/Other Information	Interpretation
Linear	Kd	0.071	A5	Very mobile
	Koc	5.0
	Notes and range	EU dossier Kd range 0.032-0.151, Koc range 3.43-7.34 mL/g, Soils=5
Freundlich	Kf	-	-	-
	Kfoc	-
	1/n	-
	Notes and range	-
pH sensitivity		Limited evidence of decreasing adsorption with increasing pH

ECOTOXICOLOGY
for clopyralid

Property		Value	Source/Quality Score/Other Information	Interpretation
Bio-concentration factor	BCF (l kg-1)	1	A5 Lepomis macrochirus	Low potential
	CT50 (days)	0.1		-
Mammals - Acute oral LD50 (mg kg-1)		> 5000	A5 Rat	Low
Mammals - Short term dietary NOEL	(mg kg-1)	> 15	L2 Rat, 2 year	High
	(ppm diet)	> 150		-
Birds - Acute LD50 (mg kg-1)		1465	A5 Anas platyrhynchos	Moderate
Birds - Short term dietary (LC50/LD50)		> 1033 mg kg bw-1 day-1	A5 Colinus virginianus	-
Fish - Acute 96 hour LC50 (mg l-1)		> 99.9	A5 Oncorhynchus mykiss	Moderate
Fish - Chronic 21 day NOEC (mg l-1)		10.8	A4 Pimephales promelas	Low
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1)		> 99	A5 Daphnia magna	Moderate
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1)		17	A5 Daphnia magna	Low
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)		50.0	A5 Chironomus riparius	Low
Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg-1)		-	-	-
Aquatic plants - Acute 7 day EC50, biomass (mg l-1)		89	A5 Lemna gibba	Low
Non-target plants		-	-	-
		-	-	-
Algae - Acute 72 hour EC50, growth (mg l-1)		30.5	A5 Raphidocelis subcapitata	Low
Algae - Chronic 96 hour NOEC, growth (mg l-1)		17	Q1 Unknown species	Low
Honeybees	Contact acute 48 hour LD50 (μg bee-1)	> 98.1	A5 Apis mellifera	Moderate
	Oral acute 48 hour LD50 (μg bee-1)	> 100	A5 Apis mellifera	Low
	Unknown mode acute 48 hour LD50 (μg bee-1)	-	-	-
Earthworms - Acute 14 day LC50 (mg kg-1)		> 1000	A5 Eisenia foetida	Low
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1)		>= 1.97	A5 Eisenia foetida	Moderate
Other soil macro-organisms - e.g. Collembola	LR50 / EC50 / NOEC / % Effect	-	-	-
Other arthropod (1)	LR50 g ha-1	2000	as mL/ha A5 Aphidius rhopalosiphi	-
	% Effect	0 90	Mortality Fecundity Dose: 0.2 kg ha-1 A5 Aphidius rhopalosiphi, adult	-
Other arthropod (2)	LR50 g ha-1	2000	as mL/ha A5 Typhlodromus pyri	-
	% Effect	5.9 27.7	Mortality Fecundity Dose: 0.2 kg ha-1 A5 Typhlodromus pyri, protonymph	-
Soil micro-organisms		Nitrogen mineralisation: No significant adverse effect Carbon mineralisation: No significant adverse effect	A5 Dose: 5 x field rate	-
Mesocosm study data	NOEAEC mg l-1	-	-	-
	NOEAEC mg l-1	-	-	-

HUMAN HEALTH AND PROTECTION
for clopyralid

General:

Property		Value	Source/Quality Score/Other Information	Interpretation
Threshold of Toxicological Concern (Cramer Class)		High (class III)	-	-
Mammals - Acute oral LD50 (mg kg-1)		> 5000	A5 Rat	Low
Mammals - Dermal LD50 (mg kg-1 body weight)		> 5000	A5 Rat	-
Mammals - Inhalation LC50 (mg l-1)		> 1.0	A5 Rat (nose only)	-
Other Mammal toxicity endpoints		-		-
ADI - Acceptable Daily Intake (mg kg-1bw day-1)		0.15	A5 Rat, SF=100	-
ARfD - Acute Reference Dose (mg kg-1bw day-1)		None allocated	A5	-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1)		-	-	-
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1)		0.15	A5	-
Dermal penetration studies (%)		25-75	A5 concentration dependent	-
Dangerous Substances Directive 76/464		-	-	-
Exposure Limits		-	-	-
Exposure Routes	Public	Minimal risk of dietary exposure
	Occupational	Risk of exposure acceptable under label recommendations for use for personal protection clothing and equipment
European MRLs		Click here for the EU MRL pesticide database
Drinking Water Standards		-	-	-
Drinking Water MAC (μg l-1)		-	-	-

Health issues:

Carcinogen	Mutagen	Endocrine disrupter	Reproduction / development effects	Cholinesterase inhibitor	Neurotoxicant
Respiratory tract irritant	Skin irritant	Skin sensitiser	Eye irritant	Phototoxicant
		-		-
General human health issues		Possible liver and kidney toxicant

: Yes, known to cause a problem
: No, known not to cause a problem
: Possibly, status not identified
- : No data found

Handling issues:

Property		Value	Source/Quality Score/Other Information	Interpretation
General		Prevent release of dust Not explosive or oxidising
CLP classification 2013		Health: H318
EC Risk Classification		Xn - Harmful: R41
EC Safety Classification		S2, S26, S39
WHO Classification		III	-	Slightly hazardous
US EPA Classification (formulation)		IV	-	Caution - Not acutely toxic
UN Number		Usually 3077
Waste disposal & packaging		Packaging Group III (minor danger)

TRANSLATIONS
for clopyralid

Language	Name
English	clopyralid
French	clopyralid
German	Clopyralid
Danish	clopyralid
Italian	clopiralid
Spanish	clopiralida
Greek	clopyralid
Slovenian	klopiralid
Polish	chlopyralid
Swedish	klopyralid
Hungarian	klopiralid
Dutch	clopyralid

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Record last updated: Thursday 23 August 2018
Contact: aeru@herts.ac.uk