ContaminantDB: Paraquat dichloride

Identification Taxonomy Biological Properties Physical Properties Toxicity Profile Spectra Concentrations Links References Targets (4)XML

Record Information

Version

1.0

Creation Date

2009-06-03 21:56:02 UTC

Update Date

2026-04-05 19:07:57 UTC

Accession Number

CHEM000721

Identification

Common Name

Paraquat dichloride

Class

Small Molecule

Description

Paraquat dichloride is a constituent of numerous proprietary herbicides. A large majority (93%) of fatalities from paraquat poisoning are cases of intentional self-administration, ie, suicides. In third world countries, paraquat is a major suicide agent. For instance, in Samoa from 1979-2001, 70% of suicides were by Paraquat poisoning. In Southern Trinidad from 1996-1997, 76% of suicides were by paraquat. However, independent bodies have studied paraquat in this use. Jenny Pronczuk de Garbino, stated: no lung or other injury in marijuana users has ever been attributed to paraquat contamination. Also a United States Environmental Protection Agency manual states: … toxic effects caused by this mechanism have been either very rare or nonexistent. Most paraquat that contaminates marijuana is pyrolyzed during smoking to dipyridyl, which is a product of combustion of the leaf material itself (including marijuana) and presents little toxic hazard. Paraquat is the trade name for N,N -dimethyl-4,4 -bipyridinium dichloride, one of the most widely used herbicides in the world. Paraquat, a viologen, is quick-acting and non-selective, killing green plant tissue on contact. It is also toxic to human beings when swallowed. Paraquat is used as a quaternary ammonium herbicide; one of the most widely used herbicides in the world. It is quick-acting, non-selective, and kills green plant tissue on contact. It is redistributed within the plant but does not harm mature bark. Being a herbicide, paraquat protects crops by controlling a wide range of annual and certain perennial weeds that reduce crop yield and quality by competing with the crop for water, nutrients, and light. Pure paraquat ingested is highly toxic to mammals and humans potentially leading to acute respiratory distress syndrome (ARDS), and there are no specific antidotes. However, fuller's earth or activated charcoal is an effective treatment, if taken in time. Death may occur up to 30 days after ingestion. Diluted paraquat used for spraying is less so, thus the greatest risk of accidental poisoning is during mixing and loading Paraquat for use.

Contaminant Sources

Clean Air Act Chemicals
FooDB Chemicals
HPV EPA Chemicals
T3DB toxins

Contaminant Type

Aromatic Hydrocarbon
Food Toxin
Herbicide
Lachrymator
Metabolite
Organic Compound
Pesticide
Synthetic Compound

Chemical Structure

MOL SDF PDB SMILES InChI

Synonyms

Value	Source
1,1'-Dimethyl-4,4'-bipyridinium	ChEBI
1,1'-Dimethyl-4,4'-bipyridyldiylium	ChEBI
Dimethyl viologen	ChEBI
Methyl viologen ion(2+)	ChEBI
N,N'-dimethyl-4,4'-bipyridinium	ChEBI
N,N'-dimethyl-4,4'-bipyridinium dication	ChEBI
Paraquat dication	ChEBI
Paraquat ion	ChEBI
Gramoxone	HMDB
Viologen, methyl	HMDB
Paragreen a	HMDB
Methyl viologen	HMDB

Chemical Formula

C₁₂H₁₄Cl₂N₂

Average Molecular Mass

257.159 g/mol

Monoisotopic Mass

256.053 g/mol

CAS Registry Number

1910-42-5

IUPAC Name

1,1'-dimethyl-[4,4'-bipyridine]-1,1'-diium

Traditional Name

starfire

SMILES

[Cl-].[Cl-].C[N+]1=CC=C(C=C1)C1=CC=[N+](C)C=C1

InChI Identifier

InChI=1S/C12H14N2.2ClH/c1-13-7-3-11(4-8-13)12-5-9-14(2)10-6-12;;/h3-10H,1-2H3;2*1H/q+2;;/p-2

InChI Key

FIKAKWIAUPDISJ-UHFFFAOYSA-L

Chemical Taxonomy

Description

belongs to the class of organic compounds known as bipyridines and oligopyridines. These are organic compounds containing two pyridine rings linked to each other.

Kingdom

Organic compounds

Super Class

Organoheterocyclic compounds

Class

Pyridines and derivatives

Sub Class

Bipyridines and oligopyridines

Direct Parent

Bipyridines and oligopyridines

Alternative Parents

Substituents

Bipyridine
4,4p-bipyridinium
N-methylpyridinium
Pyridinium
Heteroaromatic compound
Azacycle
Organic nitrogen compound
Organopnictogen compound
Hydrocarbon derivative
Organonitrogen compound
Organic cation
Aromatic heteromonocyclic compound

Molecular Framework

Aromatic heteromonocyclic compounds

External Descriptors

organic cation (CHEBI:34905 )
Bipyridinium herbicides (C14701 )
a small molecule (CPD0-2336 )

Biological Properties

Status

Detected and Not Quantified

Origin

Exogenous

Cellular Locations

Cytoplasm
Extracellular
Membrane

Biofluid Locations

Not Available

Tissue Locations

Not Available

Pathways

Not Available

Applications

Biological Roles

photosystem-I inhibitor

Chemical Roles

photosystem-I inhibitor

Physical Properties

State

Solid

Appearance

Off-white powder (6).

Experimental Properties

Property	Value
Melting Point	>400°C
Boiling Point	Not Available
Solubility	700 mg/mL at 20°C

Predicted Properties

Property	Value	Source
Water Solubility	0.00016 g/L	ALOGPS
logP	-4.2	ALOGPS
logP	-6.7	ChemAxon
logS	-6.2	ALOGPS
Physiological Charge	2	ChemAxon
Hydrogen Acceptor Count	0	ChemAxon
Hydrogen Donor Count	0	ChemAxon
Polar Surface Area	7.76 Å²	ChemAxon
Rotatable Bond Count	1	ChemAxon
Refractivity	59.19 m³·mol⁻¹	ChemAxon
Polarizability	22 Å³	ChemAxon
Number of Rings	2	ChemAxon
Bioavailability	1	ChemAxon
Rule of Five	Yes	ChemAxon
Ghose Filter	No	ChemAxon
Veber's Rule	Yes	ChemAxon
MDDR-like Rule	No	ChemAxon

Spectra

Spectrum Type	Description	Splash Key	View
Predicted LC-MS/MS	Predicted LC-MS/MS Spectrum - 10V, Positive	splash10-000i-0900000000-8e105da1b5a413b7cded	Spectrum
Predicted LC-MS/MS	Predicted LC-MS/MS Spectrum - 20V, Positive	splash10-000i-0900000000-ef5d5e61533df6c42e3e	Spectrum
Predicted LC-MS/MS	Predicted LC-MS/MS Spectrum - 40V, Positive	splash10-00yr-3900000000-42168478ffe7524d8662	Spectrum
Predicted LC-MS/MS	Predicted LC-MS/MS Spectrum - 10V, Negative	splash10-000i-0900000000-26e90595decaaf33fd6f	Spectrum
Predicted LC-MS/MS	Predicted LC-MS/MS Spectrum - 20V, Negative	splash10-000i-0900000000-85b4cce5855b8138989f	Spectrum
Predicted LC-MS/MS	Predicted LC-MS/MS Spectrum - 40V, Negative	splash10-00n0-1900000000-db10deb753c3a3973cc9	Spectrum
1D NMR	1H NMR Spectrum	Not Available	Spectrum
1D NMR	13C NMR Spectrum	Not Available	Spectrum

Toxicity Profile

Route of Exposure

Inhalation (9) ; oral (9) ; eye contat (9) ; dermal (9)

Mechanism of Toxicity

The mechanisms of the toxic effects of paraquat are largely the result of a metabolically catalyzed single electron oxidation reduction reaction, resulting in depletion of cellular NADPH and the generation of potentially toxic forms of oxygen such as the superoxide radical (3). Recent studies have demonstrated paraquat cytotoxicity occurs in the mitochondria and particularly in mitochondrial-rich tissues. The mitochondrial NADH-dependent PQ reductase containing a voltage-dependent anion channel 1 (VDAC1) appears to be largely responsible for paraquat cytotoxicity. When mitochondria are incubated with NADH and paraquat, the superoxide anion is produced, and the mitochondria rupture. Ruptured mitochondria lead to rapid cell death (4).

Metabolism

Paraquat is poorly absorbed after oral exposure. It is not metabolized but is reduced to an unstable free radical which is then re-oxidized to reform the cation and produce a superoxide anion. It is excreted moslty in the urine,and in small fraction also in the feces (2, 7).

Toxicity Values

LD50: 150 mg/kg (Oral, Rat) (7) LD50: >480 mg/kg (Dermal, Rabbit) (7)

Lethal Dose

35 mg/kg

Carcinogenicity (IARC Classification)

No indication of carcinogenicity to humans (not listed by IARC).

Uses/Sources

Paraquat is used as a quaternary ammonium herbicide; one of the most widely used herbicides in the world. It is also often used in science to catalyze the formation of reactive oxygen species (ROS). (6).

Minimum Risk Level

Not Available

Health Effects

It can cause temporary damage to nails and if swalloed, may cause nose bleeding. Long term exposures to paraquat would most likely cause lung and eye damage. Some suspect a possible link to a greater incidence of Parkinson's disease. Pancreatitis may develop in some cases of acute. Paraquat is caustic to the oral, esophageal, and gastric mucosa (8, 1, 6).

Symptoms

Eye or skin irritation; hypotension may develop after large ingestion; epistaxis and sore throat may develop after inhalation. Nausea, vomiting, diarrhea, and abdominal pain are common (8).

Treatment

In case of oral exposure, administer charcoal as a slurry. Consider after ingestion of a potentially life-threatening amount of poison if it can be performed soon after ingestion. The treatment is symptomatic and supportive. In case of eye exposure, irrigate exposed eyes with copious amounts of room temperature water for at least 15 minutes. In case of dermal exposure, remove contaminated clothing and jewellery. Wash the skin, including hair and nails, vigorously; do repeated soap washings. Discard contaminated clothing. (8)

Concentrations

Not Available

External Links

DrugBank ID

Not Available

HMDB ID

HMDB0033121

FooDB ID

FDB011120

Phenol Explorer ID

Not Available

KNApSAcK ID