| paraquat (Ref: PP 148) |
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Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home
GENERAL INFORMATION 
for paraquat
Description: A herbicide used to control common weeds in a wide range of agricultural and amenity situations
Example pests controlled: Broad-leaved weeds including cocksfoot; Grasses including wild oats, Yorkshire fog grass, ryegrass, fescue
Example applications: Rice; Lucerne; Beans & peas; Hops; Vineyards; Potaoes; Non-cropped areas such as roadways, paths
Efficacy & activity: -
Availability status: Current
Introduction & key dates: 1962
EC Regulation 1107/2009 (repealing 91/414):
| Status | Not approved |
| Dossier rapporteur/co-rapporteur | UK |
| Date inclusion expires | Expired |
| EU Candidate for substitution (CfS) | - |
| 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 |
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Also used in: Australia, USA, Canada, Mexico, Brazil, Japan, India, China, Indonesia, Thailand, New Zealand
Chemical structure:
| Isomerism | - |
| Chemical formula | C12H14N2 |
| Canonical SMILES | C[N+]1=CC=C(C=C1)C2=CC=[N+](C=C2)C |
| Isomeric SMILES | No data |
| International Chemical Identifier key (InChIKey) | INFDPOAKFNIJBF-UHFFFAOYSA-N |
| International Chemical Identifier (InChI) | InChI=1S/C12H14N2/c1-13-7-3-11(4-8-13)12-5-9-14(2)10-6-12/h3-10H,1-2H3/q+2 |
| 2D structure diagram/image available? | Yes |
General status:
| Pesticide type | Herbicide | |
| Substance group | Bipyridylium | |
| Minimum active substance purity | - | |
| Known relevant impurities | EU dossier - free 4,4¢-bipyridyl | |
| Substance origin | Synthetic | |
| Mode of action | Broad-spectrum, non-residual activity with contact and some desiccant action. Photosystem I (electron transport) inhibitor. | |
| CAS RN | 4685-14-7 | |
| EC number | 217-615-7 | |
| CIPAC number | 56 | |
| US EPA chemical code | - | |
| PubChem CID | 15939 | |
| Molecular mass (g mol-1) | 186.25 | |
| PIN (Preferred Identification Name) | - | |
| IUPAC name | 1,1'-dimethyl-4,4'-bipyridinium | |
| CAS name | 1,1'-dimethyl-4,4'-bipyridinium | |
| Other status information | PAN Dirty Dozen; Chemical subject to PIC regulations | |
| Relevant Environmental Water Quality Standards | - | |
| Herbicide Resistance Classification (HRAC) | D | |
| Herbicide Resistance Classification (WSSA) | 22 | |
| Insecticide Resistance Classification (IRAC) | Not applicable | |
| Fungicide Resistance Classification (FRAC) | Not applicable | |
| Examples of recorded resistance | Lolium rigidum | |
| Physical state | Colourless to pale yellow crystalline solid | |
| Related substances & organisms | ||
Formulations:
| Property |
Value | |||
| 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 | Often supplied as a soluble concentrate that is mixed with water and used as a spray. | |||
ENVIRONMENTAL FATE
for paraquat
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Solubility - In water at 20oC (mg l-1) | 620000 | A5 | High | |
| Solubility - In organic solvents at 20oC (mg l-1) | 143000 | A5 - Methanol | - | |
| 100 | A5 - Acetone | - | ||
| 100 | A5 - Toluene | - | ||
| 100 | A5 - Hexane | - | ||
| Melting point (oC) | - | - | - | |
| Boiling point (oC) | - | - | - | |
| Degradation point (oC) | - | - | - | |
| Flashpoint (oC) | - | - | - | |
| Octanol-water partition coefficient at pH 7, 20oC | P | 3.16 X 10-05 | Calculated | - |
| Log P | -4.5 | A5 | Low | |
| Bulk density (g ml-1)/Specific gravity | 1.5 | A5 | - | |
| Dissociation constant (pKa) at 25oC | Not applicable | A5 | - | |
| Note: No dissociation | ||||
| Vapour pressure at 20oC (mPa) | 0.01 | A3 | Low volatility | |
| Henry's law constant at 25oC (Pa m3 mol-1) | 4.00 X 10-12 | A5 | Non-volatile | |
GUS leaching potential index  |
-7.40 | Calculated | Low leachability | |
| SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate |
Value | 5.35 X 10-03 | Calculated | - |
| Note | Estimated concentrations of chemicals with Koc values greater than 9995 ml g-1 are beyond the scope of the regression data used in SCI-GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI-GROW | |||
| Potential for particle bound transport index |
- | Calculated | High | |
| Maximum UV-vis absorption L mol-1 cm-1 | 290nm | A5 | - | |
| Surface tension (mN m-1) | - | - | - | |
Degradation:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
General biodegradability | - |
| Soil degradation (days) (aerobic) | DT50 (typical) | 3000 | A5 | Very persistent |
| DT50 (lab at 20oC) | 5000 | Y3 | Very persistent | |
| DT50 (field) | 2800 | A5 | Very persistent | |
| DT90 (lab at 20oC) | - | - | - | |
| DT90 (field) | - | - | - | |
| DT50 modelling endpoint | - | - | - | |
| Note | Field studies DT50 range 7-8 years (UK) | |||
| 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 | Stable | A5 | - |
| Note | - | |||
| Aqueous hydrolysis DT50 (days) at 20oC and pH 7 | Value | Stable | A5 | - |
| Note | Stable pH 5 to pH 9, 30 days at 25 and 40 degC | |||
| Water-sediment DT50 (days) | Stable | Q2 | - | |
| Water phase only DT50 (days) | 10 | Q2 | Moderately fast | |
Soil adsorption and mobility:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Linear | Kd | - | A3 | Non-mobile |
| Koc | 1000000 | |||
| Notes and range | - | |||
| Freundlich | Kf | - | - | - |
| Kfoc | - | |||
| 1/n | - | |||
| Notes and range | - | |||
| pH sensitivity | - | |||
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| Bio-concentration factor | BCF (l kg-1) | Low risk | A5 Based on LogP < 3 | Low potential |
| CT50 (days) | - | - | ||
| Mammals - Acute oral LD50 (mg kg-1) | 110 | G4 Rat | Moderate | |
| Mammals - Short term dietary NOEL | (mg kg-1) | - | A5 Rat | - |
| (ppm diet) | > 100 | - | ||
| Birds - Acute LD50 (mg kg-1) | 35 | A4 Unknown species | High | |
| Birds - Short term dietary (LC50/LD50) | 698 mg kg feed-1 | A4 unknown species | - | |
| Fish - Acute 96 hour LC50 (mg l-1) | 19 | A5 Oncorhynchus mykiss | Moderate | |
| Fish - Chronic 21 day NOEC (mg l-1) | - | - | - | |
| Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) | 4.4 | A5 Daphnia magna | Moderate | |
| Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) | 0.12 | 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) | 0.367 | A5 Chironomus riparius | Moderate | |
| Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg-1) | > 100 | A5 Chironomus riparius | Low | |
| Aquatic plants - Acute 7 day EC50, biomass (mg l-1) | 0.037 | A5 Lemna gibba | Moderate | |
| Non-target plants | - | - | - | |
| - | - | - | ||
| Algae - Acute 72 hour EC50, growth (mg l-1) | 0.00023 | A5 Raphidocelis subcapitata | High | |
| 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) | 9.26 | A5 | Moderate |
| Oral acute LD50 (worst case from 24 , 48 and 72 hour values - μg bee-1) | > 9.06 | A5 | 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) | > 1000 | A5 Eisenia foetida | Low | |
| Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) | - | - | - | |
| Other soil macro-organisms - e.g. Collembola | LR50 / EC50 / NOEC / % Effect | - | - | - |
| Other arthropod (1) | LR50 g ha-1 | - | - | - |
| % Effect | 0 | Mortality Dose: 0.01 kg ha-1 A5 Pardosa spp., adult |
- | |
| Other arthropod (2) | LR50 g ha-1 | - | - | - |
| % Effect | 0 | Mortality Dose: 0.01 kg ha-1 A5 Aleochara bilineata, adult |
- | |
| Soil micro-organisms | Nitrogen mineralisation: No significant adverse effect Carbon mineralisation: No significant adverse effect |
A5 Dose: 720 kg ha-1, 1 year |
- | |
| Mesocosm study data | NOEAEC mg l-1 | - | - | - |
| NOEAEC mg l-1 | - | - | - | |
HUMAN HEALTH AND PROTECTION
for paraquat
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) | 110 | G4 Rat | Moderate | |
| Mammals - Dermal LD50 (mg kg-1 body weight) | > 200 | A4 Rat | - | |
| Mammals - Inhalation LC50 (mg l-1) | 0.6 | A5 Rat | - | |
| Other Mammal toxicity endpoints | - | - | ||
| ADI - Acceptable Daily Intake (mg kg-1bw day-1) | 0.004 | A5 Dog, SF=100 | - | |
| ARfD - Acute Reference Dose (mg kg-1bw day-1) | 0.005 | A5 Dog, SF=100 | - | |
| AAOEL - Acute Acceptable Operator Exposure Level (mg kg-1 bw day-1) | - | - | - | |
| AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) | 0.0004 | A5 Dog, 90 day, SF=100 | - | |
| Dermal penetration studies (%) | 0.5 | A5 | - | |
| Dangerous Substances Directive 76/464 | [No unacceptable risks to bystanders identified] | - | - | |
| Exposure Routes | Public | No unacceptable risks to operators or other workers identified | ||
| Occupational | - | |||
| European MRLs | Click here for the EU MRL pesticide database | |||
| Drinking Water Standards | - | - | - | |
| Drinking Water MAC (μg l-1) | - | - | - | |
Health issues:
| Carcinogen | Genotoxic | Endocrine disrupter | Reproduction / development effects | Cholinesterase inhibitor | Neurotoxicant | |||
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A0; B0; C0; D0; E1 |
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| Respiratory tract irritant | Skin irritant | Skin sensitiser | Eye irritant | Phototoxicant | ||||
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| General human health issues | Potential liver, kidney, stomach, intestine and respiratory system toxicant | |||||||
| Key: Genotoxicity A: Chromosome aberration (EFSA database) B: DNA damage/repair (EFSA database) C: Gene mutation (EFSA database) D: Genome mutation (EFSA database) E: Unspecified genotoxicity type (miscellaneous data source) 0: No data 1: Positive 2: Mixed/ambiguous results 3: Negative |
Key: Other : Yes, known to cause a problem  : No, known not to cause a problem  : Possibly, status not identified - : No data found |
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Handling issues:
| Property |
Value | Source/Quality Score/Other Information |
Interpretation |
|
| General |
Not explosive or oxidising IMDG Transport Code is usually 6.1 |
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| CLP classification 2013 | Health: H301, H311, H315, H319, H330, H335, H372 Environment: H400, H410 |
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| EC Risk Classification |
T+ - Very toxic: R26 T - Toxic: R24/25, R48/25 Xi - Irritant: R36/37/38 N - Dangerous for the environment: R50, R53 |
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| EC Safety Classification |
S1/2, S22, S28, S36/37/39, S45, S60, S61 | |||
| WHO Classification | II | - | Moderately hazardous | |
| UN Number | 2781 | |||
| Waste disposal & packaging |
Packaging Group II (medium danger) | |||
| Language | Name |
| English | paraquat |
| French | paraquat |
| German | Paraquat |
| Danish | paraquat |
| Italian | paraquat |
| Spanish | paracuat |
| Greek | - |
| Slovenian | parakvat |
| Polish | parakwat |
| Swedish | - |
| Hungarian | - |
| Dutch | - |
Record last updated: Thursday 24 May 2018
Contact: aeru@herts.ac.uk