Fenitrothion

Description

Fenitrothion is a selective acaricide and contact insecticide of low ovicidal properties. It is a brown to yellow liquid with a characteristic odour. Fenitrothion belongs to the organophosphate family of insecticides. It acts by inhibiting cholinesterase, thus it is an effective pesticide against a wide range of pests such as chewing, penetrating, and sucking insect pests. These pests include locusts, coffee leaf miners, wheat bugs, rice stem borers, grain weevils, and grain beetles on orchard fruits, cereals, cotton, forests, and vegetables. Fenitrothion is also an effective household insecticide as well as vector control agent for malaria.

History

Both Bayer Leverkusen and Sumitomo Chemical Company introduced Fenitrothion in 1959. Fenitrothion has minimal toxicity as compared to parathion, albeit with a range of insecticidal activity that is very similar. Fenitrothion is marketed in emulsifiable concentrate, dust, fogging concentrate, flowable, wettable powder formulations, and oil-based liquid spray.

Toxicity Effects

Acute Toxicity
Fenitrothion has acute toxicity to mammals, which is normally considered to be low. However, tests done on rats with doses considerably higher than those of applied for parathion reveal typical symptoms of acute poisoning. It also reduced the energy of birds in acute doses. Acute toxicity reported for a human female was a TDIo of 800 mg/kg.
Chronic Toxicity
In humans, chronic symptoms include fatigue, general malaise, headache, anorexia, and loss of memory, thirst, cramps, loss of weight, tremors, and muscular weakness. Half of the fenitrothion minimally effective dose changed the thyroid structure of a freshwater murrel.

Description

Fenitrothion is a volatile brownish-yellow oil.Molecular weight=277.25; Boiling point=(decomposes)at 140C; Freezing/Melting point=0.28C; Vapor pressure=5.3 3 10 2=mbar at 20C; Flash point=157C. HazardIdentification (based on NFPA-704 M Rating System):Health 3, Flammability 1, Reactivity 0. Insoluble in water.

Chemical Properties

Clear Yellow Oil

Chemical Properties

Fenitrothion is a volatile brownish-yellow oil.

Chemical Properties

Pure fenitrothion is a yellowish brown liquid with an unpleasant odor. It is insoluble in water, but readily soluble in common organic solvents, such as acetone, alcohol, benzene, chlorinated hydrocarbons, dichloromethane, 2-propanol, toluene, in ethers, methanol, and xylene. It decomposes explosively. Fenitrothion is a contact insecticide and a selective acaricide of low ovicidal properties. Fenitrothion is effective against a wide range of pests, namely, penetrating, chewing, and sucking insect pests (coffee leaf-miners, locusts, rice stem borers, wheat bugs, fl our beetles, grain beetles, grain weevils) on cereals, cotton, orchard fruits, rice, vegetables, and forests. It may also be used as a fl y, mosquito, and cockroach residual contact spray for farms and public health programs. Fenitrothion is also effective against household insects and all nuisance insects. WHO confi rmed its effectiveness as a vector control agent for malaria. It is extensively used in other countries, including Japan, where parathion has been banned. Occupational workers are exposed to fenitrothion during mixing, loading/transportation, and fi eld applications.

Uses

Fenitrothion is used to control sucking, chewing and boring insects in cereals, soft fruit, tropical fruit, vines, sugar cane, vegetables, turf and forestry. It is also used as a public health insecticide for the control of flies, cockroaches and mosquitoes. Other uses are for the control of stored product pests and locusts.

Uses

Insecticide.

Definition

ChEBI: An organic thiophosphate that is O,O-dimethyl O-phenyl phosphorothioate substituted by a methyl group at position 3 and a nitro group at position 4.

General Description

Brownish-yellow oil. Used as a selective acaricide and a contact and stomach insecticide against chewing and sucking insects on rice, orchard fruits, vegetables, cereals, cotton and forest. Also used against flies, mosquitoes, and cockroaches.

Reactivity Profile

Organophosphates, such as Fenitrothion, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides.

Hazard

Cholinesterase inhibitor, use may be restricted.

Health Hazard

Fenitrothion is toxic to animals and humans. After prolonged periods of exposures to high concentrations of fenitrothion, occupational workers show poisoning. The symptoms include, but are not limited to, general malaise, fatigue, headache, loss of memory and ability to concentrate, anorexia, nausea, thirst, loss of weight, cramps, muscular weakness, and tremors, and at suffi ciently high dosage produce typical cholinergic poisoning. The formulation product, sumithion 50EC, causes delayed neurotoxicity in adult rats, as well as humans.

Health Hazard

Fenitrothion is an organophosphate insecticide. It is a highly toxic cholinesterase inhibitor, that acts on the nervous system. Does not cause delayed neurotoxicity and contact produces little irritation.

Fire Hazard

When heated to decomposition, Fenitrothion emits very toxic fumes of oxides of nitrogen, phosphorus and sulfur. Decomposition at 212-284F produces a mixture of organophosphorus polymers. Unstable in alkaline media. Stable for 2 years if stored at 68-77F. Do not store above 104F.

Flammability and Explosibility

Not classified

Agricultural Uses

Insecticide, Acaracide: Not approved for use in EU countries. Registered for use in the U.S. This is a selective acaricide and a contact and stomach insecticide. Fenitrothion is a contact insecticide and selective acaricide of low ovicidal properties. It is considered an acetylcholinesterase inhibitor. Fenitrothion is effective against a wide range of pests, i.e. penetrating, chewing and sucking insect pests (coffee leafminers, locusts, rice stem borers, wheat bugs, flour beetles, grain beetles, grain weevils) on cereals, cotton, orchard fruits, rice, vegetables, and forests. It may also be used as a fly, mosquito, and cockroach residual contact spray for farms and public health programs. Fenitrothion is also effective against household insects and all of the nuisance insects listed by the World Health Organization. Its effectiveness as a vector control agent for malaria is confirmed by the World Health Organization. Fenitrothion is non-systemic, and non-persistent. Fenitrothion was introduced in 1959 by both Sumitomo Chemical Company and Bayer Leverkusen and later by American Cyanamid Company. Fenitrothion is far less toxic than parathion with a range of insecticidal activity that is very similar and is similar enough in structure to be produced in the same factories. The difference in precursor chemicals might make it somewhat more expensive, but it is heavily used in other countries, including Japan, where parathion has been banned. Fenitrothion comes in dust, emulsifiable concentrate, flowable, fogging concentrate, granules, ULV, oil-based liquid spray, and wettable powder formultaions. It is compatible with other neutral insecticides.

Trade name

ACCOTHION®; ACEOTHION®; AGRIA 1050®; AGRIYA 1050®; AGROTHION®; AMERICAN CYANAMID CL-47,300®; ARBOGAL®; BAY 41831®; BAYER 41831®; BAYER S 5660®; CEKUTROTHION®; CL 47300®; CP47114®; CYFEN®; CYTEL®; CYTEN®; DICATHION®; DICOFEN®; DYBAR®; EI 47300®; FALITHION®; FENITEX®; FENITOX®; FENSTAN®; FOLETHION®; FOLITHION®; H-35-F 87 (BVM)®; 8057HC®; KALEIT®; KEEN SUPERKILL ANT AND ROACH EXTERMINATOR®; KILLGERM TETRACIDE INSECTICIDAL SPRAY®; KOTION®; MEP (PESTICIDE)®; METATHION®; METATHIONE®; METATION®; MICROMITE®; MONSANTO CP 47114®; NITROPHOS®; NOVATHION®; NUVAND®; NUVANOL®; OLEOSUMIFENE®; OMS 43®; OVADOFOS®; PENNWALT C-4852; PESTROY®; S 112A®; S 5660®; SMT®; SUMITHION®[C]; TURBAIR GRAIN STORAGE INSECTICIDE®; VERTHION®

Safety Profile

Poison by ingestion, inhalation, intravenous, and intraperitoneal routes. Moderately toxic by skin contact, intratracheal, and subcutaneous routes. Human systemic effects: coma, diarrhea, dyspnea, gastrointestinal changes, hypermodtty, nausea or vomiting, respiratory depression. Mutation data reported. When heated to decomposition it emits very toxic fumes of NOx, POx, and sox

Potential Exposure

A potential danger to those involved in the manufacture, formulation, and application of this insecticide. It is a selective acaricide; and a contact and stomach insecticide. Used to control chewing and sucking insects on rice, orchard fruit; vegetables, cereals, cotton, and in forests. Also protects against flies, mosquitoes, and cockroaches

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Speed in removing material from skinis of extreme importance. Shampoo hair promptly if contaminated. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, beginrescue breathing (using universal precautions, includingresuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Effects may be delayed. Keep victim under medicalobservation.

Metabolic pathway

Fenitrothion is a non-systemic insecticide, the biotransformations and environmental fate of which have been intensively studied and reviewed. Metabolism has been studied in mammals (including humans), birds, fish, crustacea, molluscs, insects, algae, plants and soil. The major routes of biotransformation involve desulfuration to the oxon analogue (fenitrooxon) and hydrolysis to give dimethyl phosphate, O,O-dimethyl phosphorothioate and 3-methyl-4-nitrophenol. Demethylation to give desmethylfenitrothion and its decomposition products, reduction of the nitro group and oxidation of the ring methyl group also occur. Demethylation via glutathione-S-methyl transferases in the liver is a particularly important mechanism in mammals. Reduction of the nitro group to an amino group is important in anaerobic soils and ruminants but this has also been shown to occur in rats, rabbits and humans where it is presumably carried out by bacteria in the gut. Oxidation of the 3-methyl group to hydroxymethyl and carboxylate has been shown to be a degradative route in birds. The major routes of phase II metabolism involve conjugation of 3-methyl-4-nitrophenol to the glucoside in plants and insects, to the sulfate ester in birds and the sulfate ester and glucuronide in mammals.

Metabolism

The main biotransformation routes involve oxidative desulfuration to the oxon and dearylation to give dimethyl hydrogen phosphate, O,O-dimethyl hydrogen phosphorothioate and 3-methyl-4-nitrophenol. Demethylation dependent on glutathion-S-alkyl transferase is particularly important in mammals.Oxidation of the 3-methyl group to hydroxymethyl and then carboxyl group is also a degradative route. Reduction of the nitro group to an amino group occurs in anaerobic soils and ruminants. The DT₅₀ in soils under upland and submerged conditions were 12–28 and 4–20 d, respectively.

storage

Color Code—Blue: Health Hazard/Poison: Store ina secure poison location. Prior to working with this chemicalyou should be trained on its proper handling and storage.Prior to working with this chemical you should be trained onits proper handling and storage. Store in tightly closed containers in a cool, well-ventilated area away from oxidizers.Where possible, automatically pump liquid from drums orother storage containers to process containers.

Shipping

UN3017 Organophosphorus pesticides, liquid, toxic, flammable, flash point not ,23C, Hazard class: 6.1; Labels: 6.1-Poisonous materials, 3-Flammable liquid. UN2810 Toxic liquids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required

Toxicity evaluation

The acute oral LD₅₀ values in mammals range from 330 mg/kg in rats to 1850 mg/kg in the guineapig. Inhalation LC50 (4 h) for rats is >1.2 mg/L air. NOEL (2 y) for rats and mice is 10 mg/kg diet (0.5 mg/kg/d). ADI is 5 μg/kg b.w.

Degradation

Fenitrothion is relatively stable to hydrolysis under normal conditions (PM). Mikami et al. (1985) reported the hydrolysis of fenitrothion between pH 5 and 10. Below pH 7 hydrolysis occurred by a pH-independent mechanism and above pH 9 by a base-catalysed process. At intermediate pH values both mechanisms were operative. The major mechanism below pH 8 was demethylation to give desmethylfenitrothion and above pH 9, cleavage of the P-O-aryl bond gave 3-methyl-4-nitrophenol.

Incompatibilities

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases,strong acids, oxoacids, epoxides. Strong oxidizers may cause release of toxic phosphorus oxides. Organophosphates, in the presence of strong reducing agents such as hydrides, may form highly toxic and flammable phosphine gas. Keep away from alkaline materials

Waste Disposal

Incineration (for large amounts); alkaline hydrolysis and landfill (for small amounts). In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.