paraquat

H290 (100%): May be corrosive to metals [Warning Corrosive to Metals]

H301+H311 (100%): Toxic if swallowed or in contact with skin [Danger Acute toxicity, oral; acute toxicity, dermal]

H301 (100%): Toxic if swallowed [Danger Acute toxicity, oral]

H311 (100%): Toxic in contact with skin [Danger Acute toxicity, dermal]

H315 (100%): Causes skin irritation [Warning Skin corrosion/irritation]

H319 (100%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H330 (100%): Fatal if inhaled [Danger Acute toxicity, inhalation]

H335 (100%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

H372 (100%): Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

H400 (100%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

H410 (100%): Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

P234, P260, P261, P262, P264, P264+P265, P270, P271, P273, P280, P284, P301+P316, P302+P352, P304+P340, P305+P351+P338, P316, P319, P320, P321, P330, P332+P317, P337+P317, P361+P364, P362+P364, P390, P391, P403+P233, P405, P406, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 28 reports by companies from 1 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

H301: Toxic if swallowed [Danger Acute toxicity, oral]

H311: Toxic in contact with skin [Danger Acute toxicity, dermal]

H314: Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]

H318: Causes serious eye damage [Danger Serious eye damage/eye irritation]

H330: Fatal if inhaled [Danger Acute toxicity, inhalation]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

P260, P262, P264, P264+P265, P270, P271, P280, P284, P301+P316, P301+P330+P331, P302+P352, P302+P361+P354, P304+P340, P305+P354+P338, P308+P316, P316, P317, P319, P320, P321, P330, P361+P364, P363, P403+P233, P405, and P501 (click each P-code to see the statement)

P264, P270, P301+P316, P321, P330, P405, and P501 (click each P-code to see the statement)

Procedures for bipyridilium pesticides are as follows: Small fires: dry chemical, carbon dioxide, water spray, or foam. Large fires: water spray, fog, or foam. Move container from fire area if you can do so without risk. Fight fire from maximum distance. Dike fire control water for later disposal; do not scatter the material. Poisonous gases are produced in fire. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Notify local health and fire officials and pollution control agencies. Containers may explode in fire. From a secure, explosion-proof location, use water spray to cool exposed containers. If cooling streams are ineffective (venting sound increases in volume and pitch, tank discolors or shows any signs of deforming), withdraw immediately to a secure position.

If involved in a fire, control with dry powder or alcohol-resistant foam ... Protective clothing and self-contained breathing apparatus should be worn, to avoid skin contamination and the breathing of toxic fumes. Confine the use of water spray to the cooling of unaffected stock, thus avoiding the accumulation of polluted run-off from the site.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Avoid exposure by the use of appropriate protective clothing, gloves, and goggles or masks. Keep spectators away from leaking or spilled product and prevent smoking, and the use of naked flames, in the immediate vicinity ... Prevent liquid from spreading to other cargo, vegetation, or waterways by containing it with the most readily available barrier material, e.g., earth or sand. Absorb spilled liquid and cover contaminated areas with earth, lime, sand, or other absorbent material; sweep up and place in a secure container for subsequent safe disposal. Spillage: Avoid exposure by the use of appropriate protective clothing and face-shield. Empty any product remaining in damaged or leaking containers into a clean empty drum and label. Absorb spillage with lime, damp sawdust, sand, or earth and dispose of safely ... If spillage is large, contain it by building a barrier of earth or sandbags. Decontaminate empty, damaged, or leaking containers with a 10% sodium carbonate solution, added at the rate of at least 1 L per 20 L drum. Puncture or crush containers to prevent reuse.

If paraquat is spilled, ... ventilate area of spill. Collect spilled material in the most convenient and safe manner and deposit in sealed containers for reclamation. Liquid containing paraquat should be absorbed in vermiculite, dry sand, earth, or a similar material.

SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Paraquat is rapidly inactivated in soil. It is also inactivated by anionic surfactants. Therefore an effective and environmentally safe disposal method would be to mix the product with ordinary household detergent and bury the mixture in clay soil.

If incineration facilities are unavailable for a particular organic or metallo-organic pesticide (except organic mercury, lead, cadmium, and arsenic compounds), additional disposal methods include, soil injection, chemical degradation, burial (in a designated landfill), or well injection. However, persons considering the chemical degradation method should contact EPA's Regional Administrator ... prior to attempting disposal, while the well injection method should only be considered after all reasonable alternative measures have been explored and found to be less satisfactory in terms of environmental protection. If the above approved disposal methods are unavailable, temporary storage of organic and metallo-organic pesticides (except organic mercury, lead, cadmium and arsenic compounds), may be undertaken. /Organic or metallo-organic pesticide/

For more Disposal Methods (Complete) data for Paraquat (7 total), please visit the HSDB record page.

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

SRP: Contaminated protective clothing should be segregated in a manner such that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. The completeness of the cleaning procedures should be considered before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at the end of shift, but should remain at employee's place of work for cleaning.

Entry Restrictions. For sole-active-ingredient end-use products that contain paraquat the product labeling must be revised to adopt the entry restrictions set forth in this section. Any conflicting entry restrictions on the current labeling must be removed. For multiple-active-ingredient end-use products that contain paraquat the entry restrictions set forth in this section must be compared to the entry restrictions on the current labeling and the more protective must be retained. A specific time period in hours or days is considered more protective than "sprays have dried" or "dusts have settled."

The /USEPA/ is establishing the following entry restrictions for non-Worker Protection Standard occupational uses of paraquat end-use products: Do not enter or allow others to enter the treated area until sprays have dried.

For more Preventive Measures (Complete) data for Paraquat (8 total), please visit the HSDB record page.

This chemical is inactivated by inert clays and anionic surfactants. Store in tightly closed containers in a cool, well-ventilated area away from oxidizers, alkylaryl-sulfonate wetting agents, light. Where possible, automatically pump material from drums or other storage containers to process containers. Sources of ignition such as smoking and open flames are prohibited where this chemical is handled, used, or stored. Metal containers involving the transfer of this chemical should be grounded and bonded. Use only non-sparking tools and equipment, especially when opening and closing containers of this chemical. Wherever this chemical is used, handled, manufactured, or stored, use explosion-proof electrical equipment and fittings.

Store technical material and formulations away from heat, under lock and key, and out of reach of children, animals, and unauthorized personnel. Store in an area designated for pesticide storage, preferably without drains. Store away from foodstuffs and animal feed.

The compound is currently at the Holding Status AEGLs which have been reviewed by the NAC/AEGL Committee and are on hold due to insufficient data to develop AEGL values.

AEGLs Status: Holding

0.15 [mg/m3]

0.25 [mg/m3]

1.5 [mg/m3]

0.1 mg/m³ (resp)

0.5 [mg/m3], respirable dust

0.5 mg/m³ (resp dust)

1 mg/cu m /Paraquat dichloride/

0.05 [mg/m3], inhalable particulate matter, as the cation

8 hr Time Weighted Avg (TWA): 0.5 mg/cu m; 0.1 mg/cu m, respirable fraction.

Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded. /Paraquat, incl respirable fraction/

Tolerances are established for residues of the desiccant, defoliant, and herbicide paraquat (1,1'-dimethyl-4,4'-bipyridinium-ion) derived from application of either the bis(methyl sulfate) or the dichloride salt (both calculated as the cation) in or on the following food commodities:[Table#3457]

Tolerances with regional registration as defined in section 180.1(n), are established for residues of the pesticide paraquat (1,1'-dimethyl-4,4' bipyridinium ion) derived from application of either the bis(methyl sulfate) or the dichloride salt (both calculated as the cation) in or on the following food commodities:[Table#3458]

Wear appropriate personal protective equipment to prevent skin contact. /Paraquat dichloride/

Wear appropiate eye protection to prevent eye contact. /Paraquat dichloride/

Facilities for quickly drenching the body should be provided within the immediate work area for emergency use where there is a possibility of exposure. (Note: It is intended that these facilities provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.) /Paraquat dichloride/

The following minimum (baseline) PPE /are required by the USEPA/ for all occupational uses of paraquat end-use products:Mixers and loaders must wear: long-sleeved shirt and long pants, chemical-resistant gloves, shoes plus socks, chemical-resistant apron, face shield. Although there is no direct evidence that occupational handlers have ever ingested a lethal amount of paraquat from a splash or spill, the requirement for a face shield for all mixers and loaders reflects the /USEPA's/ particular concern about accidental swallowing in case of a spill or splash back.

For more Personal Protective Equipment (PPE) (Complete) data for Paraquat (10 total), please visit the HSDB record page.

Yellow, odorless solid; [HSDB] Technical grade is a dark red solution; [CHEMINFO] Commercially available as an aqueous solution with surfactants; [ACGIH]

[herbicide] [Note: Paraquat may also be found commercially as a methyl sulfate

Yellow solid

Off-white powder

...a liquid in various strengths... The form marketed in the U.S. has a blue dye to keep it from being confused with beverages, a sharp odor to serve as a warning, and an agent to cause vomiting if someone drinks it.

Yellow-white hygroscopic powder

Odorless

Boiling point (760 mm Hg): Decomposes at 175-180 °C (347-356 °F)

decomposes

Colorless crystals; mp: 300 °C (decomposes); very soluble in water, slightly soluble in lower alcohols. Insoluble in hydrocarbons. Hydrolyzed by alkali. Inactivated by inert clays and anionic surfactants; corrosive to metal; non-volatile /Paraquat dichloride/

A solid. MP: 300 °C (approximate decomposition) /Paraquat dimethyl sulfate/

572 °F (decomposes)

In water, 6.2X10+5 mg/L at 20 °C

Practically insoluble in organic solvents.

1.24 @ 20°C

0.0000001 [mmHg]

VP: Approximately 0 mm at 20 °C

Vapor pressure of salts is very low, below 1X10-7 mm Hg /Paraquat salts/

<7.5X10-8 mm Hg at 25 °C

<0.0000001 mmHg

log Kow = -4.22 at pH 7.4

Paraquat is stable in acid or neutral solutions, but is readily hydrolyzed by alkali.

When heated to decomposition it emits toxic fumes of /nitric oxides/.

Paraquat is corrosive to metals.

Colorless crystalline solid. Stable except under alkaline conditions. No measurable vapor pressure. Dcomposes at approximately 300 °C. Sparingly soluble in lower alcohols; insoluble in hydrocarbons /Paraquat dichloride/

Conversion factors: 1 mg/kg = 131 ppm; 1 ppm = 7.61 mg/cu m

White crystalline solid /Paraquat dichloride & di(methyl sulfate) salts/

Dark red solution /Technical paraquat/

MP: decomposes at 340 °C; log Kow = -4.50 (20 °C); Density: 1.24-1.26 at 20 °C; Sollubility: In water, 6.2X10+5 mg/L at 25 °C; VP: less than 7.5X10-8 mm Hg (25 °C) /Paraquat dichloride/

Yellow solid. Very air-senstive needles from MeOH/Me2CO. MW 257.18. Insoluble in nonpolar solvents /Paraquat dichloride/

Colorless hygroscopic crystals or white to yellow hygroscopic crystalline powder. Water solution of paraquat chloride is dark red. MP: 175-180 °C, BP: 300 °C (decomposes), density: 1.25. Solubility in water: 70 g/100 mL at 20 °C /Paraquat dihydride/

Yellow solid. /Paraquat bismethyl sulfide/

Carcinogens

Potential endocrine disrupting compound

Pesticide -> EPA IRIS

Herbicides

Active substance -> EU Pesticides database: Not approved

Pesticides -> Herbicides, Bipyridyl

Strong oxidizers, alkylaryl-sulfonate wetting agents [Note: Corrosive to metals. Decomposes in presence of ultraviolet light.] /Paraquat dichloride/

Strong bases

IDENTIFICATION AND USE: Paraquat is available as an odorless yellow solid, or off-white powder. The form marketed in the U.S. is a liquid with a blue dye added to keep it from being confused with beverages, a sharp odor to serve as a warning, and an agent to cause vomiting if someone drinks it. The U.S. Environmental Protection Agency classifies paraquat as "restricted use", so it can only be used by licensed applicators. It is used globally as a non-selective herbicide that kills all green plant tissue it contacts, especially grasses and weeds. It has been used for desiccation of seed crops; weed control in orchards; defoliation and desiccation of cotton; as a harvest aid in soybeans, sugarcane, guar, and sunflowers; and for killing dormant alfalfa and clover, potato vines, and marijuana plants. HUMAN EXPOSURE: Dermal exposure to paraquat usually results in minor skin or eye irritation. Rarely, with heavier exposures resulting from misuse, more serious effects may occur such as blistered or ulcerated skin, loss of fingernails, skin burns, and ulcers of the mouth, nosebleeds, and protracted or even permanent blindness. Several human deaths from ingestion or subcutaneous injection of paraquat have been reported, gradually developing lethal lung damage usually in 3 weeks (progressive fibrosis). It has been estimated that a lethal dose in man is about 14 mL of a 40% solution of paraquat. The symptoms of poisoning include burning of the mouth and throat, nausea and vomiting, respiratory distress, and transient effects on the kidneys, heart, and nervous system. In a study of 30 workers spraying paraquat over a 12 week period, approximately 50% of them had minor irritation of the eyes or nose; 1 worker had an episode of epistaxis. Of 296 spray operators with skin exposure described as gross and prolonged, 55 had damaged fingernails, the most common lesion was transverse white bands of discoloration, but loss of nail surface, transverse ridging, gross deformity of the nail plate, and loss of nails also occurred. Paraquat dichloride was weakly positive in human lymphocytes in culture cytogenetic assay, with and without metabolic activation. ANIMAL STUDIES: Two groups of rats were given a single ip dose of paraquat at 15 mg/kg. Three hr after injection, rats exhibited an uncoordinated gait and/or widely splayed limbs consistent with neurologic impairment. All paraquat-treated rats died within 42 to 96 hr. Toxicity included anorexia, adipsia, diarrhea, hyperpnea, dyspnea, and tachycardia, necrosis of liver, kidney, and GI tract with primary lesions in lungs. Paraquat provoked overt motor impairment (reduced home-cage activity and impaired vertical climbing) and signs of anxiety-like behavior (reduced open field exploration) in wild-type but not interferon-gamma (IFN-gamma) knockout mice. Correspondingly, paraquat promoted somewhat divergent variations in neurochemical activity among wild-type and IFN-gamma null mice at brain sites important for both motor (striatum) and co-morbid affective pathologies (dorsal hippocampus, medial prefrontal cortex, and locus coeruleus). In addition, the herbicide influenced serotonergic and noradrenergic activity within the dorsal hippocampus and medial prefrontal cortex; and elevated noradrenergic activity within the locus coeruleus. Paraquat has been found to have minimal to no genotoxic activity when evaluated in a variety of in vitro and in vivo test systems. In in vitro studies producing weakly positive results, paraquat genotoxicity was accompanied by high cytotoxicity. ECOTOXICITY STUDIES: Effects of the herbicide paraquat were assessed on the green freshwater alga Chlamydomonas reinhardtii. Paraquat concentrations above 0.25 uM induce toxic effects in C. reinhardtii, reflected in a significantly reduced growth rate and cell concentration with a corresponding median effective concentration (EC50) value of 0.26 uM. With increasing paraquat concentrations, an increase in cell volume was registered as well as an increase in reactive oxygen species. Several genes involved in oxidative stress defense mechanisms, such as L-ascorbate peroxidase, glutaredoxin, and a possible glutathione-S-transferase were differentially expressed. Signs of acute intoxication: Polydipsia, regurgitation, swallowing, ataxia, imbalance, wing-drop, hyporeactivity, slowness, asthenia, sitting, running and falling, and possible miosis occurred in birds exposed to paraquat. Polydipsia and regurgitation appeared as soon as 9 min and other signs of intoxication appeared 3 hr after treatment. Mortalities usually occurred between 3 and 20 hr after treatment. Remission took up to 12 days. Paraquat was found to provoke pseudo-feminization of the males during in vivo tests, where eggs were sprayed with 0.4-1.4% aqueous solution of paraquat, and in vitro tests were conducted on cultures prepared 8.5-9 days after the start of the incubation.

Paraquat

Respiratory

4.5 x 10 ^-3 mg/kg-day

CLASSIFICATION: C; possible human carcinogen. BASIS FOR CLASSIFICATION: Paraquat produced squamous cell carcinoma, an uncommon tumor, in the head region in both sexes of Fischer 344 rats. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: Limited. /Based on former classification system/

Chemical: PARAQUAT

Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.

Nephrotoxin - The chemical is potentially toxic to the kidneys in the occupational setting.

Dermatotoxin - Skin burns.

Toxic Pneumonitis - Inflammation of the lungs induced by inhalation of metal fumes or toxic gases and vapors.

Fibrogenic - Inducing tissue injury and fibrosis (scarring).

ACGIH Carcinogen - Not Classifiable.

... High dose (>40 mg paraquat ion/ kg bw = 20 mL of 20-24% concentrate): toxicity is much more severe and death occurs early (24-48 hr) from multiple organ failure. ...

Toxic concentration in blood is 0.85 mg% (8.5 ug/mL); lethal concentration in blood is 3.5 mg% (35.0 ug/mL).

Lethal concentration in blood is 3.5 mg% (35.0 ug/mL).

It has been estimated that a lethal dose in man is about 14 mL of a 40% solution of paraquat.

The minimum lethal dose of paraquat is stated to be about 35 mg/kg body weight for human beings.

LD50 Rat male oral 344 mg/kg /Paraquat dichloride/

LD50 Rale female oral 283 mg/kg /Paraquat dichloride/

LD50 Rat (female) oral 112 mg/kg bw (95% confidence interval: 104-122 mg/kg) /dose quoted as paraquat ion/ /from table/

LD50 Rat (Sprague-Dawley male) oral 223 mg/kg bw (95% confidence interval: 199-259 mg/kg) /Paraquat dichloride, purity >98%/ /from table/

For more Non-Human Toxicity Values (Complete) data for Paraquat (45 total), please visit the HSDB record page.

As a result of nuclear power plants accidents such as Chernobyl or Fukushima, some people were exposed to external and internal ionizing radiation (IR). Human brain is highly sensitive to IR during fetal and postnatal period when the molecular processes are not completely finished. Various studies have shown that exposure to low doses of IR causes a higher incidence of cognitive impairment. On the other hand, in industrialized countries, people are daily exposed to a number of toxicant pollutants. Exposure to environmental chemicals, such as paraquat (PQ), may potentiate the toxic effects induced by radiation on brain development. In this study, we evaluated the cognitive effects of concomitant exposure to low doses of internal radiation ((137)Cs) and PQ during neonatal brain development. At the postnatal day 10 (PND10), two groups of mice (C57BL/6J) were exposed to (137)Cs (4000 and 8000 Bq/kg) and/or PQ (7 mg/kg). To investigate the spontaneous behavior, learning, memory capacities and anxiety, behavioral tests were conducted in the offspring at two months of age. The results showed that cognitive functions were not significantly affected when (137)Cs or PQ were administered alone. However, alterations in the working memory and anxiety were detected in mice exposed to (137)Cs combined with PQ.

Superoxide dismutase (SOD), glutathione, and d-propranolol were evaluated for their ability to protect against paraquat dichloride toxicity in rats. SOD significantly prolonged and increased survival of exposed rats.

Female adult beagles (9-14 kg) were continuously infused with 2.5% or 5.0% taurine (into the radial vein at a rate of 0.85 mL/kg/min for 2 hr) 1 min prior to the injection of paraquat (20 mg/kg sc). Other female beagles were infused with either glycine (40 mM/dL) or 0.9% saline solution prior to paraquat challenge. Pharmacokinetic studies revealed that taurine infusion increased the blood concentration of paraquat and reduced the net content in the kidney and to a lesser extent, in the lung. The excretion of paraquat into the urine was unaltered by taurine infusion. All four beagles infused with 5.0% taurine and injected with 20 mg/kg of paraquat showed a stable condition with tail up and flicking during the infusion, whereas all control dogs given saline or glycine were vomiting and the tail was down between the legs. The infusion of 2.5% taurine had protective effects to a lesser extent against these symptoms. Urinary vol in beagles infused with 5.0% taurine and injected with paraquat was 4 times greater than that in animals given saline and the paraquat injection. The tissue/blood ratio of paraquat in beagles infused with taurine before paraquat injection was sharply reduced compared to dogs infused with saline solution or glycine.

The time required for niacin treated rats to reach 50% mortality increased from 60 to 120 hr and the death rate decreased from 75 to 55%. Niacin prevents a decrease of cellular adenine dinucleotide during paraquat poisoning as has been demonstrated in bacteria.

For more Interactions (Complete) data for Paraquat (25 total), please visit the HSDB record page.

Do not administer supplemental oxygen until the patient develops severe hypoxemia. High concentrations of oxygen in the lung increase the injury induced by paraquat and possibly by diquat as well. There may be some advantage in placing the patient in a moderately hypoxic environment, i.e., 15%-16% oxygen, although the benefit of this treatment has not been established empirically in human poisonings. Inhalation of nitric oxide has been suggested as a method to maintain tissue oxygenation at low inspired oxygen concentrations but is of unproven efficacy. When the lung injury is so far advanced that there is no expectation of recovery, oxygen may be given to relieve air hunger. /Paraquat and Diquat/

Combined glucocorticoids and cyclophosphamide pulse therapy showed promising results in moderate-to-severe paraquat poisonings to reduce life-threatening respiratory complications. Its benefit has been observed when given early in the course of poisoning; however, whether its delayed administration remains beneficial is unknown ... A 23-year-old male ... ingested 70 mL of a commercialized concentrate formulation with 20% w/v paraquat in a suicide attempt. Within 24 hr from paraquat ingestion, he presented most of the indicators of poor outcome, including gastritis, early renal dysfunction, dark blue urine colorimetric dithionite test, and marked plasma paraquat concentrations (0.56 ug/mL at 13 hr, and 0.41 ug/mL at 24 hr after ingestion). The patient received early gastrointestinal decontamination and aggressive supportive treatments. However, due to a rapidly progressive severe pulmonary infection, glucocorticoids and cyclophosphamide were delayed until day 14. Interestingly, /the/ patient survived with mild respiratory sequelae despite poor initial prognosis. This observation suggests the potential benefit of immunosuppressive pulse therapy, even if administered 14 days after paraquat ingestion, and highlights the role of paraquat-induced alveolitis in the development of fibrosis.

Forty two reports containing sufficient information of paraquat poisoned patients were evaluated. These reports, from 35 patients reported in the literature and 7 new cases, were chosen for the following reasons: the timed plasma paraquat concentrations were known, patient outcome was known, and details of hemoperfusion were available. In some cases, hemodialysis was also performed. The plasma paraquat concentrations and the specific times post-ingestion were plotted on a contour graph that predicts the probability of survival. Comparison of the predicted probability of survival versus the actual outcome showed that hemoperfusion, single or repeated, did not affect patient survival. None of the patients whose initial plasma concentrations were greater than 3 mg/L paraquat survived, regardless of the time after ingestion that the concentrations were measured, and despite hemoperfusion. Therefore, such patients might not be considered for hemoperfusion because of their uniformly bad prognosis, despite the procedure being used, and because of the morbidity, discomfort and cost associated with it.

Herbicide poisoning is most common method of suicide in India and it is associated with high morbidity and mortality. Among different herbicidal poisonings the most predominantly found poisonings are paraquat and glyphosate. These compounds are highly toxic and their poisonings require proper management techniques. High fatality is seen in these cases which are mainly due to its inherent toxicity and lack of effective treatment. Common symptoms of these poisonings includes gastrointestinal corrosive effects with mouth and throat, epigastric pain and dysphagia, acid-base imbalance, pulmonary edema, shock and arrhythmia. Long term health effects include pulmonary fibrosis, renal failure, hepatic failure, heart failure, multi-organ failure or death. No proven antidote exists for these poisonings. So the treatment is mainly supportive. Initially gastric lavage or whole-gut irrigation using adsorbents such as Fuller's earth, bentonite or activated charcoal is recommended. In case of renal failure hemodialysis or hemoperfusion may be considered. However novel approaches like treatment with N-acetylcysteine, vitamin C, vitamin E, cyclophosphamide may also be helpful /herbicide poisoning/

For more Antidote and Emergency Treatment (Complete) data for Paraquat (35 total), please visit the HSDB record page.

Recommended medical surveillance: Initial medical examinations: A complete history and physical examination /is recommended/. Examination of the eyes, respiratory system, heart, liver, and kidneys should be stressed. The skin should be examined for evidence of chronic disorders. A 14 in x 17 in chest roentgenogram, FVC and FEV (1 sec), urinalysis ... specific gravity, albumin, glucose, and a microscopic on centrifuged sediment, and liver function tests /should be performed/. The aforementioned medical examinations should be repeated on an annual basis.

/SIGNS AND SYMPTOMS/ Dermal exposure to paraquat usually results in minor skin or eye irritation. Rarely, with heavier exposures resulting from misuse, more serious effects may occur such as blistered or ulcerated skin, loss of fingernails, skin burns, ulcers of the mouth, nosebleeds, and protracted or even permanent blindness. These more serious effects typically result when protective clothing is not worn, skin has abrasions or open cuts, and/or when extensive exposure is allowed to persist without washing. The label currently warns against these hazards. Heavy, prolonged dermal exposure, as from a leaking knapsack type of sprayer, can result in severe poisoning and, rarely, even death. Six such deaths have been reported outside of the United States when workers failed to follow label requirements for proper hygiene.

/SIGNS AND SYMPTOMS/ Low dose (<20 mg paraquat ion/kg bwi = 10 mL of a 20-24% concentrate): patients are often asymptomatic or may develop vomiting or diarrhea. Complete recovery occurs but there may be a transient impairment of lung function tests. Moderate dose (20-40 mg paraquat ion/kg bw = 10 to 20 mL of 20-24% concentrate): initially renal and hepatic dysfunction are common. Mucosal damage may become apparent with sloughing of the mucous membranes in the mouth. Dyspnea may develop after a few days in the more severe cases. By about 10 days crepitations and radiological signs of lung damage usually develop. Renal function often returns to normal at this stage. Massive pulmonary fibrosis manifested by progressive dyspnea may cause death between 2-4 weeks after ingestion. High dose (>40 mg paraquat ion/ kg bw = 20 mL of 20-24% concentrate): toxicity is much more severe and death occurs early (24-48 hr) from multiple organ failure. The initial gastrointestinal symptoms are similar but very severe with considerable fluid loss. Renal failure, cardiac arrythmias, coma, convulsions, esophageal perforation, and death soon follow.

/SIGNS AND SYMPTOMS/ Paraquat is not volatile but most liquid paraquat formulations contain an unpleasant 'stenching agent' which may occasionally cause feelings of nausea or headaches. In typical spray applications the droplets are too large to be inhaled into the lungs. Inhalation of paraquat can result in a sore nose and throat as well as possible nose bleeds but there are no reports of serious systemic toxicity from inhalation. Contact of the nasal mucosa with fingers contaminated with the concentrate may also cause nose bleeds.

/SIGNS AND SYMPTOMS/ Concentrated paraquat splashes may cause severe eye irritation which may result in extensive loss of superficial areas of the corneal and conjunctival epithelium; ulcerated areas are at risk from secondary infection. Corneal edema may persist for up to 3 to 4 weeks with temporary blurring of vision.

For more Human Toxicity Excerpts (Complete) data for Paraquat (61 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ Despite a high toxicity, paraquat is one of the most widely used herbicides in the world. Our study evaluated the effect of paraquat exposure on antioxidant response and locomotion activity in Drosophila melanogaster. We examined the enzymatic activity of superoxide dismutase (SOD) and catalase, and the transcript levels of both enzymes. Flies were exposed to a wide range of paraquat concentrations (0.25 uM to 25 mM) for 12 hr. SOD, at both transcript and enzymatic levels, revealed a biphasic dose-response curve with the peak at 2.5 uM paraquat. A similar dose-response curve was observed at transcript levels of catalase. Males revealed higher susceptibility to paraquat exposure, displaying higher lethality, increased levels of SOD activity, and increased peroxide levels than in females. We found that the exposure of females to 2.5 uM paraquat leads to an increase in locomotion activity. Because susceptibility to paraquat was enhanced by mating, the study supports the hypothesis of elevation of stress sensitivity as a physiological cost of reproduction.

/LABORATORY ANIMALS: Acute Exposure/ AIMS: Paraquat Poisoning (PQ) can cause illness and death, and its main causes of mortality are acute respiratory failure and lung fibrosis. Early recognition of this condition and early treatment are vital. Thus, it is of importance to target the key genes controlling pathogenesis in the early stage of PQ. MAIN METHODS: C57BL/6 mice were used for Paraquat intragastric administration as a model of PQ. Following a gene chip-based screening, the change of gene expression in the lung was further validated by bioinformatic analyses, co-expression network construction and real-time RT-PCR, Western blot and immunofluorescence assays. KEY FINDINGS: 2287 genes with differential expression were identified at the very early stage of PQ. From these, 76 genes that were linked to mitochondrion function were further pursued. Among these genes, PSTK was a phosphorylase kinase which serves a protective role in oxidative stress lung damage. PSTK was the central gene in a 30-gene network that is important for mitochondrial complex I assembly, mitochondrial apoptosis and mitochondrial fatty acid beta-oxidation, suggesting that they could conceivably be related to the pathogenesis of PQ induced lung damage. Lastly, we confirmed that PSTK was lowered in rodent lungs following PQ. SIGNIFICANCE: PSTK emerges as a central gene in a network of mitochondrial function genes in PQ exposed mice. The functional role of PSTK in PQ induced lung injury warrants further examination.

LD50; Species: Anas platyrhynchos (Mallard) oral 199 mg/kg (95% confidence limit 144-276 mg/kg)

LD50; Species: Anas platyrhynchos (Mallard) percutaneous 600 mg/kg (95% confidence limit 424-848 mg/kg)

LC50; Species: Coturnix japonica (Japanese quail) juvenile 14 days post-hatch; diet 948 ppm for 5 days (95% confidence interval: 768-1168 ppm)

LD50; Species: Drosophila melanogaster (Fruit fly) age 5 days, wild type Oregon-R-strain; environmental exposure route 20 mM for 48 hr

For more Ecotoxicity Values (Complete) data for Paraquat (42 total), please visit the HSDB record page.

/BIRDS and MAMMALS/ Adult male bobwhite quail (Colinus virginianus) were fed a diet containing 0, 25 or 100 ppm paraquat dichloride. After 60 days on treated diets, discrimination learning was evaluated with acquisition and reversal tests. The three groups performed similarly on these tests. Dose-related histopathological lesions were not found in liver, kidney or lung tissues. /paraquat dichloride/

/BIRDS and MAMMALS/ Signs of /acute/ intoxication: Polydipsia, regurgitation, swallowing, ataxia, imbalance, wing-drop, hyporeactivity, slowness, asthenia, sitting, running and falling, and possible miosis. Polydipsia and regurgitation appeared as soon as 9 min and other signs of intoxication appeared 3 hr after treatment. Mortalities usually occurred between 3 and 20 hr after treatment; however, one bird died between 1 and 2 days after treatment. Remission took up to 12 days.

/BIRDS and MAMMALS/ The calculated percutaneous LD50 for 10 to 11 month old mallard drakes (n = 8) after a 24 hr dermal foot exposure is 600 mg/kg. Signs observed after dermal treatment included lacrimation, wings spread, using wings to aid pedestrian locomotion, and wing shivers. Mortalities occurred between 5.5 and 21.5 hr after the initiation of treatment. Remission took up to 5 days. When the percutaneous LD50 is compared with the acute oral LD50, paraquat dichloride appears to have a moderate degree of dermal hazard in mallards. /Paraquat dichloride/

/BIRDS and MAMMALS/ The action of paraquat on the urogenital tract in chicken and quail embryos was studied in vivo and in vitro. In in vivo tests, eggs were sprayed with 0.4-1.4% aqueous solution of paraquat, while in vitro tests were conducted on cultures prepared 8.5-9 days after the start of the incubation. Paraquat was found to provoke pseudo-feminization of the males. The testes presented intersexual phenomena, and the regression of the muellerian ducts was inhibited. Considerable reduction of the gonocytes in both male and female embryos, indicative of a reduction of the reproductive function, was observed. Sex- and species-specific differences in the susceptibility to paraquat were demonstrated in in vitro tests.

For more Ecotoxicity Excerpts (Complete) data for Paraquat (21 total), please visit the HSDB record page.

Paraquat's production may result in its release to the environment through various waste streams; its use as a restricted use broad spectrum herbicide will result in its direct release to the environment. If released to air, a vapor pressure of <7.5X10-8 mm Hg at 25 °C indicates paraquat will exist solely in the particulate phase in the atmosphere. Particulate-phase paraquat will be removed from the atmosphere by wet and dry deposition. Paraquat does not contain chromophores that absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight. If released to soil, paraquat is expected to have no mobility based upon reported Koc values of 15,473-1,000,000. Field studies and soil column leaching studies have demonstrated that paraquat does not leach under environmental conditions. Volatilization from moist soil surfaces is not expected based upon an estimated Henry's Law constant of <3.0X10-14 atm-cu m/mole. Paraquat is not expected to volatilize from dry soil surfaces based upon its vapor pressure. The biodegradation of paraquat is very slow when strongly adsorbed to clay or organic matters in soils because it becomes unavailable. When not in the absorbed-state, paraquat will biodegrade. Some photodegradation may occur on plant leaves or soil surfaces exposed to sunlight. Field dissipation half-lives in soil are reported as 99-4747 days. If released into water, paraquat is expected to adsorb to suspended solids and sediment based upon the reported Koc values. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. Reported BCFs of 0.05-6.9 suggest bioconcentration in aquatic organisms is low. Hydrolysis and direct photolysis in water are not expected based upon laboratory studies. Occupational exposure to paraquat may occur through inhalation and dermal contact with this compound at workplaces where paraquat is produced or used. However, the respiratory exposure to paraquat was found to be negligible compared to dermal exposure during field spraying of the herbicide. Monitoring and use data indicate that the general population may be exposed to paraquat via ingestion of food contaminated with paraquat. (SRC)

Paraquat does not occur naturally(1).

Paraquat's production may result in its release to the environment through various waste streams; its use as a restricted use broad spectrum herbicide(1) will result in its direct release to the environment(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values of 15,473-1,000,000(2-7), indicate that paraquat is expected to be immobile in soil(SRC). These values along with field studies and soil column leaching studies have demonstrated that paraquat is strongly adsorbed to soil constituents and does not leach under environmental conditions(8-10). Volatilization of paraquat from moist soil surfaces is not expected(SRC) given an estimated Henry's Law constant of <3.0X10-14 atm-cu m/mole(SRC), based upon its vapor pressure, <7.5X10-8 mm Hg(11), and water solubility, 6.2X10+5 mg/L(11). Paraquat is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(11). The biodegradation of paraquat is very slow because it strongly adsorbs to clay or organic matters in soils making paraquat unavailable to biodegrade(12). When not in the adsorbed-state, paraquat biodegrades(13-15). Some photodegradation may occur on plant leaves or soil surfaces exposed to sunlight(11-12). Field degradation half-lives in soil are reported as 99-4747 days(7,16-17).

AQUATIC FATE: Based on a classification scheme(1), reported Koc values of 15,473-1,000,000(2-7), indicate that paraquat is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(8) based upon an estimated Henry's Law constant of <3.0X10-14 atm-cu m/mole(SRC), derived from its vapor pressure, <7.5X10-8 mm Hg(9), and water solubility, 6.2X10+5 mg/L(9). Paraquat does not undergo hydrolysis based on tests conducted at pH 5, 7 and 9(10). According to a classification scheme(11), BCFs of 0.05-6.9 reported in rainbow trout, green sunfish, bluegill and channel catfish(12-13), suggest bioconcentration in aquatic organisms is low(SRC). Paraquat present in solution in the unabsorbed state may biodegrade easily in water(14). But when paraquat is adsorbed to clay or organic matter in water, biodegradation will be very slow(14-15). Paraquat will be completely removed from most surface waters in 8-12 days due to sorption to suspended solids and sediment in water; after being fixed to sediment and suspended solids, the disappearance of paraquat is slow(7).

FIELD STUDY: Paraquat resides are removed rapidly from water by adsorption on aquatic weeds and by strong adsorption to bottom mud. Decaying weeds also transport paraquat to bottom mud(1).

Table: Paraquat Concn in 2 Trials [Table#3462]

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), paraquat, which has a vapor pressure of <7.5X10-8 mm Hg at 25 °C(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase paraquat may be removed from the air by wet and dry deposition(SRC). Paraquat does not contain chromophores that absorb at wavelengths >290 nm(3) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

AEROBIC: Using microbial cultures extracted from two sandy loam soils, degradation of bioavailable (14)C paraquat was examined over a 20-36 day incubation period in the absence of light under aerobic conditions; 50% mineralization to (14)CO2 was observed within three weeks(1). Paraquat, sorbed to three plant residues (rice straw, dropwort, and Chinese milk vetch), was found to be degraded by natural microbial populations associated with the plants and/or soil under laboratory conditions(2). Degradation rates were higher under aerobic conditions than under anaerobic conditions(2). Paraquat sorbed to rice straw and placed on soil surfaces for a 60-day incubation period degraded more than 40% of applied paraquat (virtually no degradation in sterile controls), but when mixed and incorporated into soil, very little degradation occurred(2). Using bacteria from a banana farm soil, enriched cultures of three isolates, and a 21-day incubation period, paraquat recovered was 40% in unsterile soil and about 90% in sterile soil at initial concentrations of 100 mg/kg(3). Biodegradation half-lives for paraquat in sandy loam (course sand 54.8%, fine sand 31.6%, silt 22.5%, clay 10.0%, organic carbon 1.3%, pH 6.7) and muck (course sand 0.9%, fine sand 3.8%, silt 27.5%, clay 32.5%, organic carbon 30.5%, pH 4.7) were 839.2-1072 and 405.1-650.9 days, respectively; loam and muck samples were acquired from Malaysian agricultural areas(4). Reported microbiological degradation was possible only for a short time following the application of paraquat to soil(5). Once adsorbed on to clay materials, the paraquat was inaccessible to microorganisms(5). Microbial degradation of paraquat in the field is relatively slow(5).

AEROBIC: Although pure cultures of microorganisms biodegrade the herbicide in solution, paraquat bound to particulate matter or soil may biodegrade with difficulty or not at all(1). Paraquat present in solution in the unabsorbed state may biodegrade easily in water(1). But when paraquat is adsorbed to clay or organic matter in water, as for example, happens during biological sewage treatment, it may not biodegrade even after prolonged exposure(1-2). Similarly, biodegradation of paraquat strongly adsorbed to clay and organic matters in soil will not be important(1). In a calcareous soil, 13% of added paraquat degraded to CO2 after 54 days of incubation(3). Applied paraquat resided in the top one cm of sandy loam soil, when incubated at 25 °C for up to 16 months, there was no evidence of chemical or microbiological degradation(4).

ANAEROBIC: Biodegradation half-lives for paraquat in muck (course sand 0.9%, fine sand 3.8%, silt 27.5%, clay 32.5%, organic carbon 30.5%, pH 4.7) were 2289-3652 days under anaerobic conditions, muck samples were acquired from Malaysian agricultural areas(1).

PURE CULTURE: Several pure cultures of microorganisms degrade paraquat(1-6). Under aerobic conditions, biodegradation may proceed by the initial formation of 1-methyl-4,4'-bipyridylium ion, followed by 4-carboxy-1-methylpyridinium ion. Under anaerobic conditions, pure cultures of microorganisms may reduce paraquat, but no further degradation is observed(2-3). A few pure cultures of microorganisms can further metabolize the carboxylic compound to CO2, formate and succinate(2,4-5).

Paraquat dichloride did not hydrolyze in aqueous solution (91 ppm) at pH 5, 7 and 9 when incubated at 25 or 40 °C(1). Paraquat dichloride (at 299 ppm) did not photodegrade when continuously irradiated with a xenon arc lamp for 32 days at 25 °C(1). Very little photodegradation was observed when paraquat solutions were exposed to sunlight(2). However, when paraquat is adsorbed on a surface, such as plant leaves and soil, the broadening of light absorption peak maximum from 275 nm to longer wavelengths occurs, this will allow absorption of sufficient solar radiation of wavelengths >290 nm to initiate photodegradation(2). The photodegradation products of paraquat are 4-carboxy-1-methylpyridium ion and methylamine(2-3). (14)C Paraquat dichloride, applied to maize, tomato and broad-bean plants, photodegraded after 100 days with break down products of 4-carboxyl-1-methyl-(14)C-pyridylium chloride and methylamine-(14)C-hydrochloride(4). Paraquat dichloride did not photodegrade when mixed with sterile soil and exposed to natural sunlight for 85 weeks(1). Photochemical degradation of soil-bound paraquat by solar radiation is expected to be limited on soil surface, since penetration of light below the soil surface does not occur(2).

BCFs of 0.05-1.21 were reported for paraquat in rainbow trout (Salmo gairdneri), green sunfish (Lepomis cyanellus), bluegill (Lepomis macrochirus) and channel catfish (Ictalurus punctatus) after exposure for 30 days in ponds(1). The bioconcentration factor of paraquat in channel catfish (Ictalurus punctatus) was 2-6.9 in the digestive tract which was higher than any other tissues or organs(2). According to a classification scheme(3), these BCFs suggest bioconcentration in aquatic organisms is low(SRC). BCFs of <1.9 and <0.2-0.3 were reported for paraquat dichloride using carp (Cyprinus carpio) which were exposed to 0.2 and 2 mg/L over a 6-week period(4). Water snails collected from 2 ditches, 12 weeks after treatment of the waters with 1 mg/L of paraquat were found to contain 0.43 mg herbicide/kg(5).

Koc values for paraquat in various soil have been reported to be 15,473-1,000,000(1-6). According to a classification scheme(7), these Koc values suggest that paraquat is expected to be immobile in soil. Both soil thin layer chromatographic and soil leaching studies also show that paraquat will be almost immobile in soil and no significant leaching of paraquat from soil will occur(8-9). However, some leaching of paraquat may occur under conditions that are favorable for soil colloid formation (eg, with water of low electrolytic conductivity)(10). In such cases, passage of soil colloids containing adsorbed paraquat through soil pores may account for the transport of paraquat(10). Paraquat is strongly adsorbed from aquatic phase to suspended solids and sediments in water(11). Fifteen computer models (based on LEACHM and various experimental parameters) were applied to the Morgan Creek watershed (Chesapeake Bay area) and predicted that 0.00% of applied paraquat would be leached to groundwater(5).

Double positively charged paraquat cation may react with clay minerals in soil by forming complexes with the negatively charged sites on the clay minerals(1-3). Paraquat may also be adsorbed in soil by forming complexes with humic and fulvic materials present in soil(3-5). Therefore, adsorption of paraquat to soil will generally increase with the increase in clay and organic content of soil(SRC).

Paraquat was found to have high Freundlich adsorption distribution coefficients (28.7 and 1419) using Malaysian muck and sandy loam soils, respectively, that correspond to Koc values of 2207 and 4652(1); desorption studies observed negligible paraquat desorption from the muck soil and very low desorption from the sandy loam (0-0.42%)(1); soil column leaching studies found that paraquat leaching was not evident in either the sandy loam or muck soil(1). Using a dialysis technique to measure sorption and desorption to humic acid fractions extracted from soil, paraquat was rapidly adsorbed (nearly complete in 2-4 hours) with no to very low desorption over a 24-hr period(2). In sorption-desorption studies using two vineyard soils from Spain, paraquat exhibited very strong adsorption (Kd partition coefficient of 106-1280) with very small desorption(3). Paraquat has a very low soil leaching potential (5 on a scale of 100) and has a low groundwater contamination potential rating with respect to North Carolina soils and groundwaters(4). A soil column leaching study using a surface layer fine sand soil (1.3% organic carbon) and a subsurface layer fine sand (0.1% organic carbon) found a surface layer Koc of 24,441 with very slow desorption in both soils(5).

The Henry's Law constant for paraquat is estimated as <3.0X10-14 atm-cu m/mole(SRC) derived from its vapor pressure, <7.5X10-8 mm Hg(1), and water solubility, 6.2X10+5 mg/L(1). This Henry's Law constant indicates that paraquat is expected to be essentially nonvolatile from water and moist soil surfaces(2). In closed photodegradation tests using aqueous paraquat dichloride solutions over a 32-day period, no paraquat volatiles were detected(3). Paraquat is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

GROUNDWATER: Paraquat was not detected (detection limit not reported) in 358 wells in Wisconsin up to the date of June 1984(1). Paraquat was detected in one of fourteen samples of well water from Suffolk County, NY, but subsequent resampling of the same well water failed to show any paraquat(2). In a nationwide survey, paraquat was not detected in 843 groundwater samples collected from 813 wells(3). Paraquat was detected in two of 237 farm and private wells in Ontario, Canada at 11-100 and 1001-10,000 ug/L, respectively, following above ground spills(4).

DRINKING WATER: Maximum paraquat concentrations of 74 ug/L have been detected in source drinking water collected from the Sacramento-San Joaquin Delta water (sampling dates, ranges and detection limits not reported)(1).

SURFACE WATER: Paraquat was detected in a farm pond in Ontario, Canada at a concentration 70 ug/L following a spill(1). Three days after treatment with 2.2 kg paraquat/ha, the concentration in the water used to flood the treated ditches was <0.01 mg/L, and paraquat residues in the ditch water were 0.002-0.034 mg/L in samples taken 3-5 days after foliar applications(2).

SOIL: In multiple spray trials, paraquat residues in soil varied from 22 to 58 mg/kg(1).

SOURCE DOMINATED: During a 31-day sampling period between Sept and Nov 1987 in Fresno, CA, ambient paraquat concentrations were measured at four sites in a county experiencing field applications of the defoliant(1); ambient paraquat levels were all <0.022 ug/cu m(1). Mature cotton fields sprayed with paraquat at a rate of 0.94 kg/ha had average air concentrations of 4.31 and 10.7 ug/cu m downwind of application to <50 ng/cu m at 400 meters away in the same direction(2); downwind samples taken 2-4 hr after spraying contained 1-10% of the amount dispersed, after 5-7 hr, no paraquat was detectable in the air(2).

In tests on sunflower seeds treated with 0.25 or 0.5 kg paraquat/ha, residues of up to 0.9 mg/kg were found in the whole seed, up to 1.2 mg/kg in sunflower meal, and no residue in the oil(1). Paraquat was detected at 0.05 mg/kg in potatoes treated with paraquat as a desiccant, there was no change after the potatoes had been boiled(1). Paraquat was not detected (detection limit 0.02 mg/kg) in 40 composite vegetable samples from Ontario, Canada collected 1980-1985(2). Paraquat was detected in <2% of raw and processed food commodities analyzed under a regulatory monitoring program run 1978-1986 by The Food and Drug Administration(3-4). Commodities included: fruits, vegetables, grains, milk, dairy products, seafood and a variety of processed foods(3-4).

Paraquat residues detected in food crops 3-21 days after desiccation(1).[Table#3466]

Four days after application of paraquat to pond weeds at 1 mg/L, 25 mg/kg was detected on the plants(1). Paraquat residues in cotton 10 days after dessication at 0.55 kg/ha were: cotton as picked (including trash and balls) 2.00 mg/kg; ginned seed 0.18 mg/kg; mechanically reginned seed 0.08 mg/kg; acid delinated seed 0.05 mg/kg; lint cotton 3.00 mg/kg; trash 3.70 mg/kg; hulls 0.13 mg/kg; meal 0.02 mg/kg(1). Paraquat, used to eradicate marijuana plants, had residual levels of up to 461 mg/kg in treated plants(1).

Paraquat residues detected on standing cotton plant leaves was as follows: <0.01 ppm two days before treatment, 13.1 ppm two days after treatment and 8.2 ppm 6 days after treatment(1). Residues detected on lint (open bolls) was as follows: 0.01 ppm two days before treatment, 22.1 ppm two days after treatment and 3.8 ppm 6 days after treatment(1). Residues detected on seeds (open bolls) was as follows: 0.02 ppm two days before treatment, 0.06 ppm two days after treatment and 0.06 ppm 6 days after treatment(1). Paraquat residues in cotton gin waste ranged from 2.7-5.8 ppm 49 to 171 days after treatment(1). Paraquat residues in harvested seed cotton lint stored in field under tarps was 7.15 ppm 18 days after treatment and 4.85 ppm 49 days after treatment(1); residues in linter seeds was 0.25 ppm 18 days after treatment and 0.18 ppm 49 days after treatment(1).

The amount of paraquat present in airborne dust was found to range from 0.0004 to 0.001 mg/cu m(1).

Occupational exposure to paraquat may occur through inhalation and dermal contact with this compound at workplaces where paraquat is produced or used. During aerial application of paraquat to cotton in California, the dermal exposures were: flagger, 0.1-2.39 mg/hr; mixer/loader, 0.18-0.20 mg/hr; pilot, 0.05-0.26 mg/hr(1). The respiratory exposure was negligible compared to dermal exposure(1). The highest breathing zone concentration for paraquat was 26.3 ug/cu m for a flagger(1). During boom application of paraquat with tractors in tomato fields, the maximum dermal exposure of 168.6 mg/hr occurred for operators of regular tractors and a minimum of 18.4 mg/hr for operators of high clearance tractor(2). The respiratory exposure was found to be <0.1% of the dermal exposure(2). Paraquat aerosol concentration (total airborne) ranged up to 0.55 mg/cu m in the work situation, depending on the method of spraying(3). In Malaysian rubber plantations, exposure is likely to be greater than in most other situations(3). Weed control is required continuously for 10 months of the year, and the herbicide is applied by knapsack sprayers during the entire working day, 6 days a week. The high temperature and humidity together with the light clothing of the sprayers increased the potential risk of dermal exposure(3). Monitoring and use data indicate that the general population may be exposed to paraquat via ingestion of food contaminated with paraquat(SRC).

The concentration of paraquat in urine of hand-operated knapsack sprayers in Malaysian rubber plantations ranged from less than 0.01 mg/L to 0.32 mg/L during continuous spray period. Fourteen days following post-spraying, the urinary paraquat concentration was undetectable (less than 0.01 mg/L) for all sprayers(1).

SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Paraquat is rapidly inactivated in soil. It is also inactivated by anionic surfactants. Therefore an effective and environmentally safe disposal method would be to mix the product with ordinary household detergent and bury the mixture in clay soil.

If incineration facilities are unavailable for a particular organic or metallo-organic pesticide (except organic mercury, lead, cadmium, and arsenic compounds), additional disposal methods include, soil injection, chemical degradation, burial (in a designated landfill), or well injection. However, persons considering the chemical degradation method should contact EPA's Regional Administrator ... prior to attempting disposal, while the well injection method should only be considered after all reasonable alternative measures have been explored and found to be less satisfactory in terms of environmental protection. If the above approved disposal methods are unavailable, temporary storage of organic and metallo-organic pesticides (except organic mercury, lead, cadmium and arsenic compounds), may be undertaken. /Organic or metallo-organic pesticide/

For more Disposal Methods (Complete) data for Paraquat (7 total), please visit the HSDB record page.

/GUIDE 131 FLAMMABLE LIQUIDS - TOXIC/ Fire or Explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion and poison hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. /Bipyridilium pesticide, liquid, flammable, poisonous; Bipyridilium pesticide, liquid, flammable, toxic; Bipyridilium pesticide, liquid, poisonous, flammable; Bipyridilium pesticide, liquid, toxic, flammable/

/GUIDE 131 FLAMMABLE LIQUIDS - TOXIC/ Health: TOXIC; may be fatal if inhaled, ingested or absorbed through skin. Inhalation or contact with some of these materials will irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution. /Bipyridilium pesticide, liquid, flammable, poisonous; Bipyridilium pesticide, liquid, flammable, toxic; Bipyridilium pesticide, liquid, poisonous, flammable; Bipyridilium pesticide, liquid, toxic, flammable/

/GUIDE 131 FLAMMABLE LIQUIDS - TOXIC/ Public Safety: CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number listed on the inside back cover. As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering. /Bipyridilium pesticide, liquid, flammable, poisonous; Bipyridilium pesticide, liquid, flammable, toxic; Bipyridilium pesticide, liquid, poisonous, flammable; Bipyridilium pesticide, liquid, toxic, flammable/

/GUIDE 131 FLAMMABLE LIQUIDS - TOXIC/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible. /Bipyridilium pesticide, liquid, flammable, poisonous; Bipyridilium pesticide, liquid, flammable, toxic; Bipyridilium pesticide, liquid, poisonous, flammable; Bipyridilium pesticide, liquid, toxic, flammable/

For more DOT Emergency Guidelines (Complete) data for Paraquat (16 total), please visit the HSDB record page.

UN 2781: Bipyridilium pesticides, solid, toxic

UN 2782; Bipyridilium pesticides, liquid, flammable, toxic, flash point less than 23 °C

UN 3015; Bipyridilium pesticides, liquid, toxic, flammable, flash point not less than 23 °C

UN 3016; Bipyridilium pesticides, liquid, toxic

For more Shipping Name/ Number DOT/UN/NA/IMO (Complete) data for Paraquat (8 total), please visit the HSDB record page.

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials. /Bipyridilium pesticide, solid, toxic; Bipyridilium pesticide, liquid, flammable, toxic, flashpoint less than 23 °C; Bipyridilium pesticide, liquid, toxic, flammable, flashpoint 23 °C or more; Bipyridilium pesticide, liquid, toxic/

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article. /Bipyridilium pesticide, solid, toxic; Bipyridilium pesticide, liquid, flammable, toxic, flashpoint less than 23 °C; Bipyridilium pesticide, liquid, toxic, flammable, flashpoint not less than 23 °C; Bipyridilium pesticide, liquid, toxic/