Picloram (Ref: X 159868)

Picloram (Ref: X 159868)	Last updated: 26/02/2021
(Also known as: piclorame; picloram acid)

GENERAL INFORMATION

Description

A persistent herbicide for the control of broad-leaved weeds on non-crop and utility areas

Example pests controlled

Woody plants; Brush; Broad-leaved weeds including leafy spurge, knapweeds, thistles, toadflax, birdsfood trefoil and hoary cress. Will not control crucifers

Example applications

OSR; Non-cropped areas; Rangeland

Efficacy & activity

Availability status

Current

Introduction & key dates

1963

UK regulatory status

UK COPR regulatory status

Approved

Date COPR inclusion expires

31/12/2024

UK LERAP status

None

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Poland/Czech republic

Date EC 1107/2009 inclusion expires

31/12/2021

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
✓			✓		✓	✓	✓	✓

Also used in

Australia

Chemical structure

Isomerism

Chemical formula

C₆H₃Cl₃N₂O₂

Canonical SMILES

C1(=C(C(=NC(=C1Cl)Cl)C(=O)O)Cl)N

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

NQQVFXUMIDALNH-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C6H3Cl3N2O2/c7-1-3(10)2(8)5(9)11-4(1)6(12)13/h(H2,10,11)(H,12,13)

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance group

Pyridine compound

Minimum active substance purity

920 g kg⁻¹

Known relevant impurities

EU dossier - hexachlorobenzene 0.005%, sulphuric acid 0.9%

Substance origin

Synthetic

Mode of action

Selective, systemic absorbed by roots and leaves and translocated. Synthetic auxin.

CAS RN

1918-02-1

EC number

217-636-1

CIPAC number

174

US EPA chemical code

005101

PubChem CID

15965

Molecular mass

241.46

PIN (Preferred Identification Name)

IUPAC name

4-amino-3,5,6-trichloropyridine-2-carboxylic acid

CAS name

4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid

Other status information

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

Light brown to tan coloured solid

Related substances & organisms

clopyralid

2,4-D

dicamba

fluroxypyr

Formulations

Property

Value

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

Galera
Tordone 22K
Tordone 101
Grazon P+D
Amdon

Example products using this active

AgriGuard
Dow AgroSciences
Nomix Environ
Pan Agriculture

Formulation and application details

Usually suppled as a liquid concentrate or as granules

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

560

High

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

n-Heptane

105

Xylene

23900

Acetone

19100

Methanol

Melting point (°C)

174

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

179

Flashpoint (°C)

Not expected to self ignite; Not highly flammable

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

1.20 X 10^-02

Calculated

Log P

-1.92

Low

Bulk density (g ml⁻¹)

1.81

Dissociation constant pKa) at 25 °C

2.3

Strong acid

Vapour pressure at 20 °C (mPa)

8.0 X 10^-05

Low volatility

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

3.0 X 10^-07

Non-volatile

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

Unbuffered pH4.42 solution: 223nm = 28900
Acidic solution: 223nm = 28700, 293nm = 2100
Basic solution: 223nm = 30400, 293nm = 2100

Surface tension (mN m⁻¹)

72.0

at 20°C

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

82.8

Moderately persistent

DT₅₀ (lab at 20 °C)

57.6

Moderately persistent

DT₅₀ (field)

33.7

Moderately persistent

DT₉₀ (lab at 20 °C)

156

Persistent

DT₉₀ (field)

112.1

DT₅₀ modelling endpoint

Note

EU dossier Lab studies DT₅₀ range 5.2-292 days (normalised), DT₉₀ range 16.7-982.1 days; Field studies DT₅₀ range 20-49 days, DT₉₀ range 67-163 days

Dissipation rate RL₅₀ on plant matrix

Value

7.7

Note

Grass blades, n=1

Dissipation rate RL₅₀ on and in plant matrix

Value

8.0

Note

OSR leaves, n=1

Aqueous photolysis DT₅₀ (days) at pH 7

Value

2.0

Moderately fast

Note

DT₅₀: 3.5 days sterile water , 2 days natural water both in summer sunlight 40 deg N and pH 5

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

Value

Stable

Note

Stable pH 5 to pH 9, at 25 °C

Water-sediment DT₅₀ (days)

196.1

Slow

Water phase only DT₅₀ (days)

80.8

Stable

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d

Very mobile

K_oc

Notes and range

Freundlich

K_f

0.14

Very mobile

K_foc

7.22

¹/_n

0.773

Notes and range

EU dossier K_f range 0.04-0.73 mL g⁻¹, K_foc range 0.31-20.3 mL g⁻¹, ¹/_n range 0.44-1.52, Soils=14

pH sensitivity

Yes - soils pH >5 show lower adsorption

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

4.80

Calculated

High leachability

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

Value

1.99 X 10⁰⁰

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Very mobile

Calculated

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Metabolising enzymes

4-amino-3,5-dichloro-6-hydroxypicolinic acid

6-OH picloram

Plant

4-amino-2,3,5-trichloropyridine (Ref: K-041160)

PYR

Plant

oxamic acid

Water (Photolysis)

3-oxo-beta-alanine

Water (Photolysis)

aminopyralid (Ref: XDE 750)

Water; Sediment

ECOTOXICOLOGY

Property

Value

Source; quality score; and other information

Interpretation

Bio-concentration factor

BCF (l kg⁻¹)

Whole fish

Low potential

CT₅₀ (days)

Not available

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

4012

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat 2 year

(ppm diet)

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

> 1000

Rat Reproductive NOAEL

Low

Birds - Acute LD₅₀ (mg kg⁻¹)

> 1944

Anas platyrhynchos

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5620 mg kg feed⁻¹

Colinus virginianus

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

Colinus virginianus

Moderate

Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

8.8

Oncorhynchus mykiss

Moderate

Fish - Chronic 21 day NOEC (mg l⁻¹)

0.55

Oncorhynchus mykiss

Moderate

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

44.2

Daphnia magna

Moderate

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

6.79

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)

100

Chironomus riparius

Low

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

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

102

Lemna gibba

Low

Non-target plants

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

60.2

Pseudokirchneriella subcapitata

Low

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)

> 100

Apis mellifera

Low

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

> 74

Apis mellifera

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)

> 4475

Eisenia foetida

Low

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

0.167

Eisenia foetida 56 days

Moderate

Other soil macro-organisms

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Other arthropod (1)

LR₅₀ g ha⁻¹

23.45

Aphidius rhopalosiphi

% Effect

Other arthropod (2)

LR₅₀ g ha⁻¹

23.45

Typhlodromus pyri

% Effect

Soil micro-organisms

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)

4012

Rat

Low

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 0.035

Rat 4 hr (whole body)

Other Mammal toxicity endpoints

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

0.3

Rabbit SF=100

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

0.3

Rabbit 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)

0.3

Rabbit SF=100

Dermal penetration studies (%)

0.1-10.0

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

No unacceptable risks to operators or other workers identified

MRLs

European

EU MRL pesticide database

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

0.1

EU Dir 89/778/EC limit; Calc MAC=900 µg l⁻¹

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

No data found

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Slightly toxic
IARC Group 3 carcinogen; USEPA - some evidence to suggest not a human carcinogen

Handling issues

Property

Value and interpretation

General

Prevent generation of dust
Not oxidising or explosive
IMDG Transport Code is usually 9

CLP classification 2013

Health: H302, H312, H319, H332, H335
Environment: H400, H410, H412

EC Risk Classification

N - Dangerous for the environment: R51, R53

EC Safety Classification

S60, S61

WHO Classification

U (Unlikely to present an acute hazard)

UN Number

Usually 3082

Waste disposal & packaging

Packaging Group III (minor danger)

TRANSLATIONS

Language

Name

English

picloram

French

piclorame

German

Picloram

Danish

picloram

Italian

picloram

Spanish

picloram

Greek

Polish

pikloram

Swedish

pikloram

Hungarian

Dutch

Record last updated:	26/02/2021
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