| picloram (Ref: X 159868) |
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Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home
GENERAL INFORMATION 
for picloram
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
EC Regulation 1107/2009 (repealing 91/414):
| Status | Approved |
| Dossier rapporteur/co-rapporteur | Poland/Czech republic |
| Date inclusion expires | 31/12/2018 |
| EU Candidate for substitution (CfS) | No |
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 |
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Also used in: Australia
General status:
| Pesticide type | Herbicide | |
| Substance group | Pyridine compound | |
| Minimum active substance purity | 920 g/kg | |
| 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 | |
| Isomerism | - | |
| Chemical formula | C6H3Cl3N2O2 | |
| SMILES | Clc1c(N)c(Cl)c(nc1Cl)C(=O)O | |
| 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) | |
| Structure diagram/image available? | Yes | |
| Molecular mass (g mol-1) | 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 | - | |
| 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 | Light brown to tan coloured solid | |
| Related substances & organisms | ||
Formulations:
| Property |
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| Example manufacturers & suppliers of products using this active now or historically |
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| Example products using this active |
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| UK LERAP status | None | |||
| Formulation and application details | Usually suppled as a liquid concentrate or as granules. | |||
ENVIRONMENTAL FATE
for picloram
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Solubility - In water at 20oC (mg l-1) | 560 | A5 | High | |
| Solubility - In organic solvents at 20oC (mg l-1) | 10 | A5 - n-Heptane | - | |
| 105 | A5 - Xylene | - | ||
| 23900 | A5 - Acetone | - | ||
| 19100 | A5 - Methanol | - | ||
| Melting point (oC) | 174 | A5 | - | |
| Boiling point (oC) | Decomposes before boiling | A5 | - | |
| Degradation point (oC) | 179 | A5 | - | |
| Flashpoint (oC) | Not expected to self ignite; Not highly flammable | A5 | - | |
| Octanol-water partition coefficient at pH 7, 20oC | P | 1.20 X 10-02 | Calculated | - |
| Log P | -1.92 | A5 | Low | |
| Bulk density (g ml-1)/Specific gravity | 1.81 | Q2 | - | |
| Dissociation constant (pKa) at 25oC | 2.3 | A5 | - | |
| Note: Strong acid | ||||
| Vapour pressure at 25oC (mPa) | 8.0 X 10-05 | A5 | Low volatility | |
| Henry's law constant at 25oC (Pa m3 mol-1) | 3.0 X 10-07 | A5 | Non-volatile | |
GUS leaching potential index  |
6.03 | Calculated | High leachability | |
| SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate |
Value | 1.17 X 10+01 | Calculated | - |
| Note | - | |||
| Potential for particle bound transport index |
- | Calculated | Medium | |
| 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 | A5 | - | |
| Surface tension (mN m-1) | 72.0 | A5 at 20oC | - | |
Degradation:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
General biodegradability | - |
| Soil degradation (days) (aerobic) | DT50 (typical) | 82.8 | A5 | Moderately persistent |
| DT50 (lab at 20oC) | 82.8 | A5 | Moderately persistent | |
| DT50 (field) | 36 | A4 | Moderately persistent | |
| DT90 (lab at 20oC) | 318 | A5 | - | |
| DT90 (field) | 120 | A5 | - | |
| DT50 modelling endpoint | - | - | - | |
| Note | EU dossier Lab studies DT50 range 5.2-292 days, 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 | R3 | - |
| Note | Grass blades, n=1 | |||
| Dissipation rate RL50 on and in plant matrix | Value | 8.0 | R3 | - |
| Note | OSR leaves, n=1 | |||
| Aqueous photolysis DT50 (days) at pH 7 | Value | 2.0 | A5 | 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 20oC and pH 7 | Value | Stable | A5 | - |
| Note | Stable pH 5 to pH 9, at 25 degC | |||
| Water-sediment DT50 (days) | 196.1 | A5 | Slow | |
| Water phase only DT50 (days) | 80.8 | A5 | Stable | |
Soil adsorption and mobility:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Linear | Kd | - | DW3 | Very mobile |
| Koc | 13 | |||
| Notes and range | - | |||
| Freundlich | Kf | 0.14 | A5 | Very mobile |
| Kfoc | 7.22 | |||
| 1/n | 0.773 | |||
| Notes and range | EU dossier Kf range 0.04-0.73 mL/g, Kfoc range 0.31-20.3 mL/g, 1/n range 0.44-1.52, Soils=14 | |||
| pH sensitivity | Yes - soils pH >5 show lower adsorption | |||
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 | - | - |
| oxamic acid | - | Water (Photolysis) | - | - |
| 3-oxo-beta-alanine | - | Water (Photolysis) | - | - |
| 4-amino-2,3,5-trichloropyridine (Ref: K-041160) |
PYR | Plant | - | - |
| aminopyralid (Ref: XDE 750) Note: A5 |
- | Water; Sediment | - | - |
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Bio-concentration factor | BCF (l kg-1) | 74 | F4 Whole fish | Low potential |
| CT50 (days) | Not available | - | ||
| Mammals - Acute oral LD50 (mg kg-1) | 4012 | A5 Rat | Low | |
| Mammals - Short term dietary NOEL | (mg kg-1) | - | L2 Rat, 2 year | - |
| (ppm diet) | 20 | - | ||
| Birds - Acute LD50 (mg kg-1) | > 1944 | A5 Anas platyrhynchos | Moderate | |
| Birds - Short term dietary (LC50/LD50) | > 5620 mg kg feed-1 | A5 Colinus virginianus | - | |
| Fish - Acute 96 hour LC50 (mg l-1) | 8.8 | A5 Oncorhynchus mykiss | Moderate | |
| Fish - Chronic 21 day NOEC (mg l-1) | 0.55 | A5 Oncorhynchus mykiss | Moderate | |
| Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) | 44.2 | A5 Daphnia magna | Moderate | |
| Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) | 6.79 | A5 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 | 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) | 102 | A5 Lemna gibba | Low | |
| Non-target plants | - | - | - | |
| - | - | - | ||
| Algae - Acute 72 hour EC50, growth (mg l-1) | 60.2 | A5 Pseudokirchneriella subcapitata | Low | |
| Algae - Chronic 96 hour NOEC, growth (mg l-1) | - | - | - | |
| Honeybees | Contact acute 48 hour LD50 (μg bee-1) | > 100 | A5 | Low |
| Oral acute 48 hour LD50 (μg bee-1) | > 74 | A5 | Moderate | |
| Unknown mode acute 48 hour LD50 (μg bee-1) | - | - | - | |
| Earthworms - Acute 14 day LC50 (mg kg-1) | > 4475 | A5 Eisenia foetida | Low | |
| Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) | 0.167 | A5 Eisenia foetida, 56 days | Moderate | |
| Other soil macro-organisms - e.g. Collembola | LR50 / EC50 / NOEC / % Effect | - | - | - |
| Other arthropod (1) | LR50 g ha-1 | 23.45 | A5 Aphidius rhopalosiphi | - |
| % Effect | - | - | - | |
| Other arthropod (2) | LR50 g ha-1 | 23.45 | A5 Typhlodromus pyri | - |
| % Effect | - | - | - | |
| Soil micro-organisms | - | - | - | |
| Mesocosm study data | NOEAEC mg l-1 | - | - | - |
| NOEAEC mg l-1 | - | - | - | |
HUMAN HEALTH AND PROTECTION
for picloram
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) | 4012 | A5 Rat | Low | |
| Mammals - Dermal LD50 (mg kg-1 body weight) | > 2000 | A5 Rat | - | |
| Mammals - Inhalation LC50 (mg l-1) | > 0.035 | A5 Rat, 4 hr (whole body) | - | |
| Other Mammal toxicity endpoints | - | - | ||
| ADI - Acceptable Daily Intake (mg kg-1bw day-1) | 0.3 | A5 Rabbit, SF=100 | - | |
| ARfD - Acute Reference Dose (mg kg-1bw day-1) | 0.3 | A5 Rabbit, SF=100 | - | |
| AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) | 0.3 | A5 Rabbit, SF=100 | - | |
| Dermal penetration studies (%) | 0.1-10.0 | A5 concentration dependent | - | |
| Dangerous Substances Directive 76/464 | - | - | - | |
| Exposure Limits | [LT TWA 8hr: 10 mg/m3], [ST 15 mins: 20 mg/m3] | MEL UK HSE | - | |
| Exposure Routes | Public | No unacceptable risks to bystanders identified | ||
| Occupational | No unacceptable risks to operators or other workers identified | |||
| European MRLs | Click here for the EU MRL pesticide database | |||
| Drinking Water MAC (μg l-1) | 0.1 | EU Dir 89/778/EC limit; Calc MAC=900 μg l-1; A5 | - | |
Health issues:
| Carcinogen | Mutagen | Endocrine disrupter | Reproduction / development effects | Cholinesterase inhibitor | Neurotoxicant | |||
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| Respiratory tract irritant | Skin irritant | Skin sensitiser | Eye irritant | Phototoxicant | ||||
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| General human health issues | Slightly toxic IARC Group 3 carcinogen; USEPA - some evidence to suggest not a human carcinogen |
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: 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 generation of dust Not oxidising or explosive IMDG Transport Code is usually 9 |
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| CLP classification 2013 | None allocated at this time | |||
| EC Risk Classification |
N - Dangerous for the environment: R51, R53 | |||
| EC Safety Classification |
S60, S61 | |||
| WHO Classification | U | - | Unlikely to present an acute hazard | |
| US EPA Classification (formulation) | I | - | Danger - Highly toxic | |
| UN Number | Usually 3082 | |||
| Waste disposal & packaging |
Packaging Group III (minor danger) | |||
| Language | Name |
| English | picloram |
| French | piclorame |
| German | Picloram |
| Danish | picloram |
| Italian | picloram |
| Spanish | picloram |
| Greek | - |
| Slovenian | pikloram |
| Polish | pikloram |
| Swedish | pikloram |
| Hungarian | - |
| Dutch | - |
Record last updated: Tuesday 20 March 2018
Contact: aeru@herts.ac.uk